A first principle approach for clover detector

Science.gov (United States)

Kshetri, R.

2012-08-01

A simple model based on probability flow arguments has been presented for understanding the clover germanium detector. Using basic concepts of absorption and scattering of gamma-rays, the operation of the clover detector has been described in terms of six probability amplitudes and a parameter. Instead of using an empirical method or simulation, this work presents the first attempt to calculate the peak-to-total and peak-to-background ratios of the clover detector using experimental data of relative single crystal efficiency and addback factor as an input. A unique feature of our approach is that these ratios could be calculated for energies where their direct measurement is impossible due to absence of a radioactive source having single monoenergetic gamma-ray of that energy. Results for four gamma-ray energies (Eγ = 1.408, 3.907, 7.029 and 10.430 MeV) have been discussed. Agreement between experimental data and analysis results has been observed. The present approach could describe clover-type detectors as well. As an example, the nine element detector has been considered. We have demonstrated that our formalism can describe both finite and infinite interactions of γ-rays with the clover crystals. The work presented in this paper follows similar philosophy as presented in a recent paper (R. Kshetri, JInst 2012 7 P04008), which deals with modeling of encapsulated type composite detectors like miniball, cluster and SPI (Spectrometer for INTEGRAL satellite).

A first principle approach for clover detector

International Nuclear Information System (INIS)

Kshetri, R

2012-01-01

A simple model based on probability flow arguments has been presented for understanding the clover germanium detector. Using basic concepts of absorption and scattering of gamma-rays, the operation of the clover detector has been described in terms of six probability amplitudes and a parameter. Instead of using an empirical method or simulation, this work presents the first attempt to calculate the peak-to-total and peak-to-background ratios of the clover detector using experimental data of relative single crystal efficiency and addback factor as an input. A unique feature of our approach is that these ratios could be calculated for energies where their direct measurement is impossible due to absence of a radioactive source having single monoenergetic gamma-ray of that energy. Results for four gamma-ray energies (E γ = 1.408, 3.907, 7.029 and 10.430 MeV) have been discussed. Agreement between experimental data and analysis results has been observed. The present approach could describe clover-type detectors as well. As an example, the nine element detector has been considered. We have demonstrated that our formalism can describe both finite and infinite interactions of γ-rays with the clover crystals. The work presented in this paper follows similar philosophy as presented in a recent paper (R. Kshetri, JInst 2012 7 P04008), which deals with modeling of encapsulated type composite detectors like miniball, cluster and SPI (Spectrometer for INTEGRAL satellite).

Wilson flow and scale setting from lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Bornyakov, V.G. [Institute for High Energy Physics, Protvino (Russian Federation); Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Far Eastern Federal Univ., Vladivostok (Russian Federation). School of Biomedicine; Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Hudspith, R. [York Univ., Toronto, ON (Canada). Dept. of Mathematics and Statistics; Collaboration: QCDSF-UKQCD Collaboration; and others

2015-08-15

We give a determination of the phenomenological value of the Wilson (or gradient) flow scales t{sub 0} and w{sub 0} for 2+1 flavours of dynamical quarks. The simulations are performed keeping the average quark mass constant, which allows the approach to the physical point to be made in a controlled manner. O(a) improved clover fermions are used and together with four lattice spacings this allows the continuum extrapolation to be taken.

Impact on Clover-Grass Yield from Wheel Load and Tyre Pressure

DEFF Research Database (Denmark)

Green, Ole; Jørgensen, Rasmus Nyholm; Sørensen, Claus Aage Grøn

2009-01-01

Traffic intensities have been shown to have a negative influence on the yield of grass and clover. A full scale grass-clover field trial was established to estimate the effect on clover-grass yields as a function of different wheel loads and tire pressures. The trial comprised 16 different traffi...

The H dibaryon on the lattice

Energy Technology Data Exchange (ETDEWEB)

Wetzorke, I. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Karsch, F. [Bielefeld Univ. (Germany). Fakultaet fuer Physik

2002-08-01

We present our final results for the mass of the six quark flavor singlet state (J{sup P}=0{sup +}, S=-2) called H dibaryon, which would be the lightest possible strangelet in the context of strange quark matter. The calculations are performed in quenched QCD on (8-24){sup 3} x 30 lattices with the (1,2) Symanzik improved gauge action and the clover fermion action. Furthermore the fuzzing technique for the fermion fields and smearing of the gauge fields is applied in order to enhance the overlap with the ground state. Depending on the lattice size we observe an H mass slightly above or comparable with the {lambda}{lambda} threshold for strong decay. Therefore a bound H dibaryon state seemed to be ruled out by our simulation. (orig.)

The H dibaryon on the lattice

Energy Technology Data Exchange (ETDEWEB)

Wetzorke, I.; Karsch, F

2003-05-01

We present our final results for the mass of the six quark flavor singlet state (J{sup P} = 0{sup +}, S = -2) called H dibaryon, which would be the lightest possible strangelet in the context of strange quark matter. The calculations are performed in quenched QCD on (8 - 24){sup 3} x 30 lattices with the (1,2) Symanzik improved gauge action and the clover fermion action. Furthermore the fuzzing technique for the fermion fields and smearing of the gauge fields is applied in order to enhance the overlap with the ground state. Depending on the lattice size we observe an H mass slightly above or comparable with the AA threshold for strong decay. Therefore a bound H dibaryon state seemed to be ruled out by our simulation.

Sources of N2O in organic grass-clover pastures

OpenAIRE

Ambus, P.

2002-01-01

Organic farming practises, and in particular dairy production systems based on grass-clover pastures are becoming increasingly abundant within Danish agriculture. Grass-clover pastures may provide a mitigation option to reduce grassland nitrous oxide (N2O) emissions (Velthof et al. 1998). The objectives of this work was to examine the relationship between N2O emissions and transformations of inorganic N in organically managed grass-clover pastures of different ages. Results from the projec...

Application of various technological processes in red clover seed processing

OpenAIRE

Đokić, Dragoslav; Stanisavljević, Rade; Terzić, Dragan; Marković, Jordan; Radivojević, Gordana; Anđelković, Bojan; Barać, Saša

2012-01-01

This paper presents the results of the processing of natural red clover seed on the processing equipment using different technological methods. Red clover seed, for the establishment and crop utilization, must be of high purity, germination, and high genetic values. These requirements are achieved by processing, or removing impurities and poor quality seeds. Red clover seed processing involves a number of operations, of which the most important are: cleaning, packaging, labeling and storage. ...

Perturbative determination of c{sub sw} for plaquette and Symanzik gauge action and stout link clover fermions

Energy Technology Data Exchange (ETDEWEB)

Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics; Perlt, H.; Schiller, A. [Leipzig Univ. (Germany). Inst. fuer Theoretische Physik; Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Division, Dept. of Mathematical Sicences; Schierholz, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

2008-06-15

Using plaquette and Symanzik improved gauge action and stout link clover fermions we determine the improvement coefficient c{sub SW} in one-loop lattice perturbation theory from the off-shell quark-quark-gluon three-point function. In addition, we compute the coefficients needed for the most general form of quark field improvement and present the one-loop result for the critical hopping parameter {kappa}{sub c}. We discuss mean field improvement for c{sub SW} and {kappa}{sub c} and the choice of the mean field coupling for the actions we have considered. (orig.)

Scattering phase shift for elastic two pion scattering and the rho resonance in lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Gutzwiller, Simone

2012-10-08

In this thesis we use lattice QCD to compute scattering phase shifts for elastic two-pion scattering in the isospin I=1 channel. Using Luescher's formalism, we derive the scattering phase shifts for different total momenta of the two-pion system in a non-rest frame. Furthermore we analyse the symmetries of the non-rest frame lattices and construct 2-pion and rho operators transforming in accordance with these symmetries. The data was collected for a 32{sup 3} x 64 and a 40{sup 3} x 64 lattice with N{sub f}=2 clover improved Wilson fermions at a pion mass around 290 MeV and a lattice spacing of about 0.072 fm.

Scattering phase shift for elastic two pion scattering and the rho resonance in lattice QCD

International Nuclear Information System (INIS)

Gutzwiller, Simone

2012-01-01

In this thesis we use lattice QCD to compute scattering phase shifts for elastic two-pion scattering in the isospin I=1 channel. Using Luescher's formalism, we derive the scattering phase shifts for different total momenta of the two-pion system in a non-rest frame. Furthermore we analyse the symmetries of the non-rest frame lattices and construct 2-pion and rho operators transforming in accordance with these symmetries. The data was collected for a 32 3 x 64 and a 40 3 x 64 lattice with N f =2 clover improved Wilson fermions at a pion mass around 290 MeV and a lattice spacing of about 0.072 fm.

A first look at maximally twisted mass lattice QCD calculations at the physical point

International Nuclear Information System (INIS)

Abdel-Rehim, A.

2013-11-01

In this contribution, a first look at simulations using maximally twisted mass Wilson fermions at the physical point is presented. A lattice action including clover and twisted mass terms is presented and the Monte Carlo histories of one run with two mass-degenerate flavours at a single lattice spacing are shown. Measurements from the light and heavy-light pseudoscalar sectors are compared to previous N f =2 results and their phenomenological values. Finally, the strategy for extending simulations to N f =2+1+1 is outlined.

Specific activity isolation and determination of radioactive Estrogenic Substances in White Clover

International Nuclear Information System (INIS)

Pupiales T, G.; Mejia M, G.

1986-01-01

Due to high number of leguminous that exhibit estrogenic activity, subterranean clover between others, which causes infertility in sheep that eat it. It has been considered that white clover (Trifolium repens, variety Ladino, is an specie of low estrogenic activity, however at Bogota City (Colombia) it has high estrogenic activity and may cause reduction in the dairy cattle fertility. Research done in the IAN (today Ingeominas) over this clover variety, showed that the radioactivity substances presents in the white clover have high activity for stradiol, affecting organs from mouse females; Isoflavonoids from vegetables have an anabolism and utero tropic action; estrogenic activity of clover leaves, was exponentially proportional to the amount of ultraviolet radioactivity, falling upon plants during leaves development stage

Coherent-potential approximation for the lattice vibrations of mixed III-V crystals

International Nuclear Information System (INIS)

Kleinert, P.

1984-01-01

The coherent-potential approximation (CPA) is applied to the lattice dynamics of some III-V mixed crystals. The calculations are based on an eleven-parameter rigid-ion model (RIM 11). Explicit results are reported for the one-mode system In/sub 1-c/Ga/sub c/P and the two mixed-mode crystals In/sub 1-c/Ga/sub c/Sb and GaSb/sub 1-c/As/sub c/. Both, the reflectivity spectra and the composition dependence of vibrations at the GAMMA and X points are compared with existing experimental data. Force-constant changes are considered by the virtual-crystal approximation (VCA). The CPA theory is uniquely successful for III-V mixed-mode systems, which appear to switch from one-mode to two-mode behaviour. (author)

Lattice study of finite volume effect in HVP for muon g-2

Directory of Open Access Journals (Sweden)

Izubuchi Taku

2018-01-01

Full Text Available We study the finite volume effect of the hadronic vacuum polarization contribution to muon g-2, aμhvp,in lattice QCD by comparison with two different volumes, L4 = (5.44 and (8.14 fm4, at physical pion. We perform the lattice computation of highly precise vector-vector current correlator with optimized AMA technique on Nf = 2 + 1 PACS gauge configurations in Wilson-clover fermion and stout smeared gluon action at one lattice cut-off, a−1 = 2.33 GeV. We compare two integrals of aμhvp, momentum integral and time-slice summation, on the lattice and numerically show that the different size of finite volume effect appears between two methods. We also discuss the effect of backward-state propagation into the result of aμhvp with the different boundary condition. Our model-independent study suggest that the lattice computation at physical pion is important for correct estimate of finite volume and other lattice systematics in aμhvp.

Lattice study of finite volume effect in HVP for muon g-2

Science.gov (United States)

Izubuchi, Taku; Kuramashi, Yoshinobu; Lehner, Christoph; Shintani, Eigo

2018-03-01

We study the finite volume effect of the hadronic vacuum polarization contribution to muon g-2, aμhvp, in lattice QCD by comparison with two different volumes, L4 = (5.4)4 and (8.1)4 fm4, at physical pion. We perform the lattice computation of highly precise vector-vector current correlator with optimized AMA technique on Nf = 2 + 1 PACS gauge configurations in Wilson-clover fermion and stout smeared gluon action at one lattice cut-off, a-1 = 2.33 GeV. We compare two integrals of aμhvp, momentum integral and time-slice summation, on the lattice and numerically show that the different size of finite volume effect appears between two methods. We also discuss the effect of backward-state propagation into the result of aμhvp with the different boundary condition. Our model-independent study suggest that the lattice computation at physical pion is important for correct estimate of finite volume and other lattice systematics in aμhvp.

Fate in Soil of Flavonoids Released from White Clover (Trifolium repens L.)

DEFF Research Database (Denmark)

Carlsen, Sandra C. K.; Pedersen, Hans A.; Spliid, Niels H.

2012-01-01

the presence in soil of bioactive secondary metabolites from clover has received limited attention. In this paper we examine for the first time the release of flavonoids both from field-grown white clover and from soil-incorporated white clover plants of flavonoids, as analyzed by LC-MS/MS. The dominant...... flavonoid aglycones were formononetin, medicarpin, and kaempferol. Soil-incorporated white clover plants generated high concentrations of the glycosides kaempferol-Rha-Xyl-Gal and quercetin-Xyl-Gal. Substantial amounts of kaempferol persisted in the soil for days while the other compounds were degraded...

Reduction in clover-grass yield caused by different traffic intensities

DEFF Research Database (Denmark)

Green, Ole; Jørgensen, Rasmus Nyholm; Kristensen, Kristian

Different traffic intensities have been shown to have a negative influence on the yield of grass and clover. A full scale grass-clover field trial was established to estimate the effect on clover-grass yields as a function of different wheel loads and tire pressures. The trial comprised 16...... close to the north, south and east border of the field. No significant interactions were found between the timing of crop and soil damage as affected by wheel load and tire pressure. However, at specific times, there was a significant effect of wheel load and secondary by the tire pressure. At all...... measurement times, the yield was lower using a wheel load of 4745 kg than for a wheel load of 2865 kg.     Key words (for Electronic Reference Library) Traffic intensities, tire load/pressure, clover/grass, yield loss, ...

A first look at maximally twisted mass lattice QCD calculations at the physical point

Energy Technology Data Exchange (ETDEWEB)

Abdel-Rehim, A. [The Cyprus Institute, Nicosia (Cyprus). CaSToRC; Boucaud, P. [Paris XI Univ., Orsay (France). Laboratoire de Physique Theorique; Carrasco, N. [Valencia-CSIC Univ. (Spain). Dept. de Fisica Teorica; IFIC, Valencia (Spain); and others

2013-11-15

In this contribution, a first look at simulations using maximally twisted mass Wilson fermions at the physical point is presented. A lattice action including clover and twisted mass terms is presented and the Monte Carlo histories of one run with two mass-degenerate flavours at a single lattice spacing are shown. Measurements from the light and heavy-light pseudoscalar sectors are compared to previous N{sub f}=2 results and their phenomenological values. Finally, the strategy for extending simulations to N{sub f}=2+1+1 is outlined.

Algorithms for Disconnected Diagrams in Lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Gambhir, Arjun Singh [College of William and Mary, Williamsburg, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Stathopoulos, Andreas [College of William and Mary, Williamsburg, VA (United States); Orginos, Konstantinos [College of William and Mary, Williamsburg, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Yoon, Boram [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gupta, Rajan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Syritsyn, Sergey [Stony Brook Univ., NY (United States)

2016-11-01

Computing disconnected diagrams in Lattice QCD (operator insertion in a quark loop) entails the computationally demanding problem of taking the trace of the all to all quark propagator. We first outline the basic algorithm used to compute a quark loop as well as improvements to this method. Then, we motivate and introduce an algorithm based on the synergy between hierarchical probing and singular value deflation. We present results for the chiral condensate using a 2+1-flavor clover ensemble and compare estimates of the nucleon charges with the basic algorithm.

Nucleon wave function from lattice QCD

International Nuclear Information System (INIS)

Warkentin, Nikolaus

2008-04-01

In this work we develop a systematic approach to calculate moments of leading-twist and next-to-leading twist baryon distribution amplitudes within lattice QCD. Using two flavours of dynamical clover fermions we determine low moments of nucleon distribution amplitudes as well as constants relevant for proton decay calculations in grand unified theories. The deviations of the leading-twist nucleon distribution amplitude from its asymptotic form, which we obtain, are less pronounced than sometimes claimed in the literature. The results are applied within the light cone sum rule approach to calculate nucleon form factors that are compared with recent experimental data. (orig.)

Nucleon wave function from lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Warkentin, Nikolaus

2008-04-15

In this work we develop a systematic approach to calculate moments of leading-twist and next-to-leading twist baryon distribution amplitudes within lattice QCD. Using two flavours of dynamical clover fermions we determine low moments of nucleon distribution amplitudes as well as constants relevant for proton decay calculations in grand unified theories. The deviations of the leading-twist nucleon distribution amplitude from its asymptotic form, which we obtain, are less pronounced than sometimes claimed in the literature. The results are applied within the light cone sum rule approach to calculate nucleon form factors that are compared with recent experimental data. (orig.)

Clover, Red (Trifolium pretense)

Science.gov (United States)

Genetic modification of plants by the insertion of transgenes can be a powerful experimental approach to answer basic questions about gene product function. This technology can also be used to make improved crop varieties for use in the field. To apply this powerful tool to red clover, an important ...

Estimating grass-clover ratio variations caused by traffic intensities using image analysis

DEFF Research Database (Denmark)

Jørgensen, Rasmus Nyholm; Sørensen, Claus Grøn; Green, Ole

Grass and especially clover have a negative yield response as a function of  traffic intensity.  Conventional grass-clover production for silage have high traffic intensity due to fertilizing with slurry, cutting the grass, rolling the grass into swaths, and collecting and chopping the grass...... to fulfill the aim [1]http://www.ruralni.gov.uk/index/publications/press_articles/dairy-2/role-of-clover.htm...

In situ carbon and nitrogen dynamics in ryegrass-clover mixtures

DEFF Research Database (Denmark)

Rasmussen, J.; Eriksen, J.; Jensen, Erik Steen

2007-01-01

=9). 15N-enriched compounds were not detected in percolating pore water, which may be caused by either dilution from irrigation or low availability of leachable N compounds. 14C was found solely as 14CO2 in the pore water indicating that dissolved organic carbon (DOC) did not originate from fresh......Carbon (C) and nitrogen (N) dynamics in a third production year ryegrass–clover mixture were investigated in the field. Cylinders (diameter 29.7 cm) were installed to depths of 20, 40 and 60 cm and equipped with suction cups to collect percolating pore water. Ryegrass and clover leaves were cross......-labelled with 14C- and 15N-enriched urea and the fate of the two tracers was studied for 3 months during summer. Transfer of 14C occurred mainly from ryegrass to clover, whereas the largest transfer of 15N was in the opposite direction. The average transfer of N from clover was 40% (SE±3.1, n=9) of N in ryegrass...

Potential for yield in red clover (Trifolium pratense L. varieties

Directory of Open Access Journals (Sweden)

Vasiljević Sanja

2010-01-01

Full Text Available Red clover (Trifolium pratense L. is botanically a perennial, although it often behaves as a biennial. The crop usually lives 2 to 3 seasons in most clover-growing regions of the world and is generally conceded to be lacking in persistence. The objective of this investigation was to analyze the production potential and persistence of domestic and imported red clover varieties. Experiments were conducted at Rimski Šančevi Experiment Field during the period 2004-2006. The experimental materials were six varieties (K-17, Kolubara, Una, Viola, Start, Nike which were analyzed for the most important production characteristics: yield of green mass, dry matter yield and persistence. .

Elastic I=3 /2 p -wave nucleon-pion scattering amplitude and the Δ (1232) resonance from Nf=2+1 lattice QCD

DEFF Research Database (Denmark)

Andersen, Christian Walther; Bulava, John; Hörz, Ben

2018-01-01

We present the first direct determination of meson-baryon resonance parameters from a scattering amplitude calculated using lattice QCD. In particular, we calculate the elastic I=3/2, p-wave nucleon-pion amplitude on a single ensemble of Nf=2+1 Wilson-clover fermions with mπ=280 MeV and mK=460 Me......V. At these quark masses, the Δ(1232) resonance pole is found close to the N-π threshold and a Breit-Wigner fit to the amplitude gives gΔNπBW=19.0(4.7) in agreement with phenomenological determinations.......We present the first direct determination of meson-baryon resonance parameters from a scattering amplitude calculated using lattice QCD. In particular, we calculate the elastic I=3/2, p-wave nucleon-pion amplitude on a single ensemble of Nf=2+1 Wilson-clover fermions with mπ=280 MeV and mK=460 Me...

Nucleon distribution apmlitudes and proton decay matrix elements on the lattice

Energy Technology Data Exchange (ETDEWEB)

Braun, Vladimir M.; Goeckeler, Meinulf [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Horsley, Roger [Edinburgh Univ. (GB). School of Physics] (and others)

2008-11-15

Baryon distribution amplitudes (DAs) are crucial for the theory of hard exclusive reactions. We present a calculation of the first few moments of the leading-twist nucleon DA within lattice QCD. In addition we deal with the normalization of the next-to-leading (twist-four) DAs. The matrix elements determining the latter quantities are also responsible for proton decay in Grand Unified Theories. Our lattice evaluation makes use of gauge field configurations generated with two flavors of clover fermions. The relevant operators are renormalized nonperturbatively with the final results given in the MS scheme. We find that the deviation of the leading-twist nucleon DA from its asymptotic form is less pronounced than sometimes claimed in the literature. (orig.)

Leaching of cyanogenic glucosides and cyanide from white clover green manure

DEFF Research Database (Denmark)

Bjarnholt, Nanna; Lægdsmand, Mette; Hansen, Hans Chr. Bruun

2008-01-01

Use of crops for green manure as a substitute for chemical fertilizers and pesticides is an important approach towards more sustainable agricultural practices. Green manure from white clover is rich in nitrogen but white clover also produces the cyanogenic glucosides (CGs) linamarin...... and lotaustralin; CGs release toxic hydrogen cyanide (HCN) upon hydrolysis which may be utilized for pest control. We demonstrate that applying CGs in the form of a liquid extract of white clover to large columns of intact agricultural soils can result in leaching of toxic cyanide species to a depth of at least 1...

Lattice renormalisation of O(a) improved heavy-light operators

International Nuclear Information System (INIS)

Blossier, B.

2007-05-01

Analytical expressions and numerical values of renormalisation constants of O(a) improved heavy-light currents are given at 1-loop order of perturbation theory in the framework of Heavy Quark Effective Theory: the heavy quark is described by the HYP action and the light quark is described either with the Clover or the Neuberger action. These factors are relevant to extract from a lattice computation the decay constants f B , f B S and the set of bag parameters B i associated with B- anti B mixing phenomenology in the Standard Model and beyond. (orig.)

Estimating the content of clover and grass in the sward using a consumer camera and image processing

DEFF Research Database (Denmark)

Mortensen, Anders Krogh; Karstoft, Henrik; Søegaard, Karen

the dry matter ratio of clover and grass in clover grass fields from sparse close up images. First, the light conditions is determined, which is used for selecting model parameters to estimate the coverage of both clover and grass. Next, the clover and grass coverage are transformed to give the dry matter...

Cumulative effects of white clover residues on the changes in soil ...

African Journals Online (AJOL)

White clover grows naturally all over the Himalayan regions including the hilly areas of the state of Azad Jammu and Kashmir (AJK), Pakistan. This study was conducted to investigate the effects of white clover residues alone or in combination with phosphorus (P) fertilizer on maize (Zea mays L.) yield, nutrient uptake and ...

Linyphiid spider populations in sustainable wheat‐clover bi‐cropping compared to conventional wheat‐growing practice

DEFF Research Database (Denmark)

Gravesen, Eigil Vestergaard

2008-01-01

Linyphiid web densities in wheat-clover bi-crop systems where winter wheat was grown in an under-storey of white clover were compared with web densities estimated in conventional wheat-growing systems. The web densities in the wheat-clover bi-crop systems were on average between 200 and 250 webs ...

Does white clover (Trifolium repens abundance in temperate pastures determine Sitona obsoletus (Coleoptera: Curculionidae larval populations?

Directory of Open Access Journals (Sweden)

Mark Richard McNeill

2016-09-01

Full Text Available To determine if host plant abundance determined the size of clover root weevil (CRW Sitona obsoletus larval populations, a study was conducted over four years in plots sown in ryegrass (Lolium perenne (cv. Nui sown at either 6 or 30 kg/ha and white clover (Trifolium repens sown at a uniform rate of 8 kg/ha. This provided a range of % white clover content to investigate CRW population establishment and impacts on white clover survival. Larval sampling was carried out in spring (October when larval densities are near their spring peak at Lincoln (Canterbury, New Zealand with % clover measured in autumn (April and spring (September of each year. Overall, mean larval densities measured in spring 2012, 2013, 2014 and 2015 were 310, 38, 59 and 31 larvae m-2, respectively. There was a significant decline in larval populations between 2012 and 2013, but spring populations were relatively uniform thereafter. The mean % white clover measured in autumns of 2012 to 2015 was 17, 10, 3 and 11%, respectively. In comparison, mean spring % white clover from 2012 to 2015, averaged c. 5% each year. Analysis relating spring (October larval populations to % white clover measured in each plot in autumn (April found the 2012 larval population to be statistically significantly larger in the ryegrass 6 kg/ha plots than 30 kg/ha plots. Thereafter, sowing rate had no significant effect on larval populations. From 2013 to 2015, spring larval populations had a negative relationship with the previous autumn % white clover with the relationship highly significant for the 2014 data. When CRW larval populations in spring 2013 to 2015 were predicted from the 2013 to 2015 autumn % white clover, respectively, based on their positive relationship in 2012, the predicted densities were substantially larger than those observed. Conversely, when 2015 spring larval data and % clover was regressed against 2012-2014 larval populations, observed densities tended to be higher than predicted

Does White Clover (Trifolium repens) Abundance in Temperate Pastures Determine Sitona obsoletus (Coleoptera: Curculionidae) Larval Populations?

Science.gov (United States)

McNeill, Mark R; van Koten, Chikako; Cave, Vanessa M; Chapman, David; Hodgson, Hamish

2016-01-01

To determine if host plant abundance determined the size of clover root weevil (CRW) Sitona obsoletus larval populations, a study was conducted over 4 years in plots sown in ryegrass ( Lolium perenne ) (cv. Nui) sown at either 6 or 30 kg/ha and white clover ( Trifolium repens ) sown at a uniform rate of 8 kg/ha. This provided a range of % white clover content to investigate CRW population establishment and impacts on white clover survival. Larval sampling was carried out in spring (October) when larval densities are near their spring peak at Lincoln (Canterbury, New Zealand) with % clover measured in autumn (April) and spring (September) of each year. Overall, mean larval densities measured in spring 2012-2015 were 310, 38, 59, and 31 larvae m -2 , respectively. There was a significant decline in larval populations between 2012 and 2013, but spring populations were relatively uniform thereafter. The mean % white clover measured in autumns of 2012 to 2015 was 17, 10, 3, and 11%, respectively. In comparison, mean spring % white clover from 2012 to 2015, averaged c. 5% each year. Analysis relating spring (October) larval populations to % white clover measured in each plot in autumn (April) found the 2012 larval population to be statistically significantly larger in the ryegrass 6 kg/ha plots than 30 kg/ha plots. Thereafter, sowing rate had no significant effect on larval populations. From 2013 to 2015, spring larval populations had a negative relationship with the previous autumn % white clover with the relationship highly significant for the 2014 data. When CRW larval populations in spring 2013 to 2015 were predicted from the 2013 to 2015 autumn % white clover, respectively, based on their positive relationship in 2012, the predicted densities were substantially larger than those observed. Conversely, when 2015 spring larval data and % clover was regressed against 2012-2014 larval populations, observed densities tended to be higher than predicted, but the numbers

Estimation of the Botanical Composition of Clover-Grass Leys from RGB Images Using Data Simulation and Fully Convolutional Neural Networks

Science.gov (United States)

Steen, Kim Arild; Green, Ole; Karstoft, Henrik

2017-01-01

Optimal fertilization of clover-grass fields relies on knowledge of the clover and grass fractions. This study shows how knowledge can be obtained by analyzing images collected in fields automatically. A fully convolutional neural network was trained to create a pixel-wise classification of clover, grass, and weeds in red, green, and blue (RGB) images of clover-grass mixtures. The estimated clover fractions of the dry matter from the images were found to be highly correlated with the real clover fractions of the dry matter, making this a cheap and non-destructive way of monitoring clover-grass fields. The network was trained solely on simulated top-down images of clover-grass fields. This enables the network to distinguish clover, grass, and weed pixels in real images. The use of simulated images for training reduces the manual labor to a few hours, as compared to more than 3000 h when all the real images are annotated for training. The network was tested on images with varied clover/grass ratios and achieved an overall pixel classification accuracy of 83.4%, while estimating the dry matter clover fraction with a standard deviation of 7.8%. PMID:29258215

Assessment of nickel bioavailability through chemical extractants and red clover (Trifolium pratense L.) in an amended soil: Related changes in various parameters of red clover.

Science.gov (United States)

Shahbaz, Ali Khan; Iqbal, Muhammad; Jabbar, Abdul; Hussain, Sabir; Ibrahim, Muhammad

2018-03-01

Application of immobilizing agents may efficiently reduce the bioavailability of nickel (Ni) in the soil. Here we report the effect of biochar (BC), gravel sludge (GS) and zeolite (ZE) as a sole treatment and their combinations on the bioavailability of Ni after their application into a Ni-polluted soil. The bioavailability of Ni after the application of immobilizing agents was assessed through an indicator plant (red clover) and chemical indicators of bioavailability like soil water extract (SWE), DTPA and Ca(NO 3 ) 2 extracts. Additionally, the effects of Ni bioavailability and immobilizing agents on the growth, physiological and biochemical attributes of red clover were also observed. Application of ZE significantly reduced Ni concentrations in all chemical extracts compared to rest of the treatments. Similarly, the combined application of BC and ZE (BC+ ZE) significantly reduced Ni concentrations, reactive oxygen species (ROS) whereas, significant enhancement in the growth, physiological and biochemical attributes along with an improvement in antioxidant defence machinery of red clover plant, compared to rest of the treatments, were observed. Furthermore, BC+ ZE treatment significantly reduced bioconcentration factor (BCF) and bioaccumulation factor (BAF) of Ni in red clover, compared to rest of the treatments. The Ni concentrations in red clover leaves individually reflected a good correlation with Ni concentrations in the extracts (SWE at R 2 =0.79, DTPA extract at R 2 =0.84 and Ca(NO 3 ) 2 extracts at R 2 =0.86). Our results indicate that combined application of ZE and BC can significantly reduce the Ni bioavailability in the soil while in parallel improve the antioxidant defence mechanism in plants. Copyright © 2017 Elsevier Inc. All rights reserved.

Modelling interactions in grass-clover mixtures

NARCIS (Netherlands)

Nassiri Mahallati, M.

1998-01-01

The study described in this thesis focuses on a quantitative understanding of the complex interactions in binary mixtures of perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) under cutting. The first part of the study describes the dynamics of growth, production

Spectroscopy of doubly and triply-charmed baryons from lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Padmanath, M. [Tata Institute; Edwards, Robert G. [JLAB; Mathur, Nilmani [Tata Institute; Peardon, Michael [Trinity College, Dublin

2013-11-01

We present the ground and excited state spectra of doubly and triply-charmed baryons by using lattice QCD with dynamical clover fermions. A large set of baryonic operators that respect the symmetries of the lattice and are obtained after subduction from their continuum analogues are utilized. Using novel computational techniques correlation functions of these operators are generated and the variational method is exploited to extract excited states. The lattice spectra that we obtain have baryonic states with well-defined total spins up to 7/2 and the low lying states remarkably resemble the expectations of quantum numbers from SU(6) Ⓧ O(3) symmetry. Various energy splittings between the extracted states, including splittings due to hyperfine as well as spin-orbit coupling, are considered and those are also compared against similar energy splittings at other quark masses. Using those splittings for doubly-charmed baryons, and taking input of experimental Bc meson mass, we predict the mass splittings of B*c-Bc to be about 80 ± 8 MeV and mΩccb=8050±10 MeV.

Transformation kinetics of corn and clover residues in mineral substrates of different composition

Science.gov (United States)

Pinskii, D. L.; Maltseva, A. N.; Zolotareva, B. N.; Dmitrieva, E. D.

2017-06-01

Mineralization kinetics of corn and clover residues in quartz sand, loam, sand + 15% bentonite, and sand + 30% kaolinite have been studied. A scheme has been proposed for the transformation of plant residues in mineral substrates. Kinetic parameters of mineralization have been calculated with the use of a first-order two-term exponential polynomial. It has been shown that the share of labile organic carbon pool in the clover biomass is higher (57-63%) than in the corn biomass (47-49%), which is related to the biochemical composition of plant residues. The mineralization constants of clover residues generally significantly exceed those of corn because of the stronger stabilization of the decomposition products of corn residues. The turnover time of the labile clover pool (4-9 days) in all substrates and that of the labile corn pool (8-10 days) in sands and substrates containing kaolinites and bentonite are typical for organic acids, amino acids, and simple sugars. In the loamy substrate, the turnover time of labile corn pool is about 46 days due to the stronger stabilization of components of the labile pool containing large amounts of organic acids. The turnover time of the stable clover pool (0.95 years) is significantly lower than that of the stable corn pool (1.60 years) and largely corresponds to the turnover time of plant biomass.

Determination of lattice parameters, strain state and composition in semipolar III-nitrides using high resolution X-ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Frentrup, Martin, E-mail: frentrup@physik.tu-berlin.de; Wernicke, Tim; Stellmach, Joachim; Kneissl, Michael [Institute of Solid State Physics, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin (Germany); Hatui, Nirupam; Bhattacharya, Arnab [Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India)

2013-12-07

In group-III-nitride heterostructures with semipolar or nonpolar crystal orientation, anisotropic lattice and thermal mismatch with the buffer or substrate lead to a complex distortion of the unit cells, e.g., by shearing of the lattice. This makes an accurate determination of lattice parameters, composition, and strain state under assumption of the hexagonal symmetry impossible. In this work, we present a procedure to accurately determine the lattice constants, strain state, and composition of semipolar heterostructures using high resolution X-ray diffraction. An analysis of the unit cell distortion shows that four independent lattice parameters are sufficient to describe this distortion. Assuming only small deviations from an ideal hexagonal structure, a linear expression for the interplanar distances d{sub hkl} is derived. It is used to determine the lattice parameters from high resolution X-ray diffraction 2ϑ-ω-scans of multiple on- and off-axis reflections via a weighted least-square fit. The strain and composition of ternary alloys are then evaluated by transforming the elastic parameters (using Hooke's law) from the natural crystal-fixed coordinate system to a layer-based system, given by the in-plane directions and the growth direction. We illustrate our procedure taking an example of (112{sup ¯}2) Al{sub κ}Ga{sub 1−κ}N epilayers with Al-contents over the entire composition range. We separately identify the in-plane and out-of-plane strains and discuss origins for the observed anisotropy.

Inexpensive chirality on the lattice

International Nuclear Information System (INIS)

Kamleh, W.; Williams, A.G.; Adams, D.

2000-01-01

Full text: Implementing lattice fermions that resemble as closely as possible continuum fermions is one of the main goals of the theoretical physics community. Aside from a lack of infinitely powerful computers, one of the main impediments to this is the Nielsen-Ninomiya No-Go theorem for chirality on the lattice. One of the consequences of this theorem is that exact chiral symmetry and a lack of fermion doublers cannot be simultaneously satisfied for fermions on the lattice. In the commonly used Wilson fermion formulation, chiral symmetry is explicitly sacrificed on the lattice to avoid fermion doubling. Recently, an alternative has come forward, namely, the Ginsparg-Wilson relation and one of its solutions, the Overlap fermion. The Ginsparg-Wilson relation is a statement of lattice-deformed chirality. The Overlap-Dirac operator is a member of the family of solutions of the Ginsparg-Wilson relation. In recent times, Overlap fermions have been of great interest to the community due to their excellent chiral properties. However, they are significantly more expensive to implement than Wilson fermions. This expense is primarily due to the fact that the Overlap implementation requires an evaluation of the sign function for the Wilson-Dirac operator. The sign function is approximated by a high order rational polynomial function, but this approximation is poor close to the origin. The less near-zero modes that the Wilson- Dirac operator possesses, the cheaper the Overlap operator will be to implement. A means of improving the eigenvalue properties of the Wilson-Dirac operator by the addition of a so-called 'Clover' term is put forward. Numerical results are given that demonstrate this improvement. The Nielsen-Ninomiya no-go theorem and chirality on the lattice are reviewed. The general form of solutions of the Ginsparg-Wilson relation are given, and the Overlap solution is discussed. Properties of the Overlap-Dirac operator are given, including locality and analytic

A New NPGS Special Collection: Norman L. Taylor University of Kentucky Clover Collection

Science.gov (United States)

Dr. Norman L. Taylor was a world renowned Professor and clover breeder in the Department of Plant and Soil Sciences at the University of Kentucky for 48 years. Following retirement in 2001, he continued working on clovers up until his death in 2010. Dr. Taylor’s entire career was devoted to enhancin...

ππ P-wave resonant scattering from lattice QCD

Directory of Open Access Journals (Sweden)

Paul Srijit

2018-01-01

Full Text Available We present a high-statistics analysis of the ρ resonance in ππ scattering, using 2 + 1 flavors of clover fermions at a pion mass of approximately 320 MeV and a lattice size of approximately 3:6 fm. The computation of the two-point functions are carried out using combinations of forward, sequential, and stochastic propagators. For the extraction of the ρ-resonance parameters, we compare different fit methods and demonstrate their consistency. For the ππ scattering phase shift, we consider different Breit-Wigner parametrizations and also investigate possible nonresonant contributions. We find that the minimal Breit-Wigner model is suffcient to describe our data, and obtain amρ = 0:4609(16stat(14sys and gρππ = 5:69(13stat(16sys. In our comparison with other lattice QCD results, we consider the dimensionless ratios amρ/amN and amπ/amN to avoid scale setting ambiguities.

ππ P-wave resonant scattering from lattice QCD

Science.gov (United States)

Paul, Srijit; Alexandrou, Constantia; Leskovec, Luka; Meinel, Stefan; Negele, John W.; Petschlies, Marcus; Pochinsky, Andrew; Rendon Suzuki, Jesus Gumaro; Syritsyn, Sergey

2018-03-01

We present a high-statistics analysis of the ρ resonance in ππ scattering, using 2 + 1 flavors of clover fermions at a pion mass of approximately 320 MeV and a lattice size of approximately 3:6 fm. The computation of the two-point functions are carried out using combinations of forward, sequential, and stochastic propagators. For the extraction of the ρ-resonance parameters, we compare different fit methods and demonstrate their consistency. For the ππ scattering phase shift, we consider different Breit-Wigner parametrizations and also investigate possible nonresonant contributions. We find that the minimal Breit-Wigner model is suffcient to describe our data, and obtain amρ = 0:4609(16)stat(14)sys and gρππ = 5:69(13)stat(16)sys. In our comparison with other lattice QCD results, we consider the dimensionless ratios amρ/amN and amπ/amN to avoid scale setting ambiguities.

N transfer in three species grass-clover mixtures with chicory, ribwort plantain or caraway

DEFF Research Database (Denmark)

Dhamala, Nawa Raj; Rasmussen, Jim; Carlsson, Georg

2017-01-01

Background and aimsThere is substantial evidence that legume-derived Nitrogen (N) is transferred to neighboring non-legumes in grassland mixtures. However, there is sparse information about how deep rooted non-legume forage herbs (forbs) influence N transfer in multi-species grasslands. Methodology......Red clover (Trifolium pretense L.) was grown together with perennial ryegrass (Lolium perenne L.) and one of three forb species: chicory (Cichorium intybus L.), ribwort plantain (Plantago lanceolata L.) or caraway (Carum carvi L.) in a field experiment. During the first year after the establishment, red...... clover leaves were labeled with 15N-urea to determine the N transfer from red clover to companion ryegrass and forbs. ResultsOn an annual basis, up to 15 % of red clover N was transferred to the companion ryegrass and forbs, but predominantly to the grass. The forb species did not differ in their ability...

The Clover detector

Energy Technology Data Exchange (ETDEWEB)

Beck, F A; Byrski, Th; Durien, D; Duchene, G; France, G de; Kharraja, B; Wei, L [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Butler, P; Jones, G; Jones, P [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Hannachi, F [Daresbury Lab. (United Kingdom)

1992-08-01

The EUROGAM Phase I device is almost running for experiments and new technical developments are in progress for its second phase. For example, a composite Ge detector should enable: a very large photopeak efficiency with good energy and timing resolutions; and, the covering, with Ge, of a large portion of 4{pi}-Str. The Clover detector, proposed by the CRN, Strasbourg, is one of this new generation of Ge detectors. It is currently developed in France by the EUROGAM collaboration. The design, the technical characteristics of the counter and the first results of the prototype tests are discussed in this contribution. (author). 1 ref., 2 tabs., 2 refs.

Inclusion of caraway in the ryegrass-red clover mixture modifies soil microbial community composition

DEFF Research Database (Denmark)

Cong, Wenfeng; Jing, Jingying; Søegaard, Karen

-containing grass-clover mixtures may potentially affect soil microbial community structure, biomass and associated ecosystem functions, but it is yet to be elucidated. We hypothesized that inclusion of plantain in the grass-clover mixture would enhance soil microbial biomas and functions through its high biomass...

Multicolor (UV-IR) Photodetectors Based on Lattice-Matched 6.1 A II/VI and III/V Semiconductors

Science.gov (United States)

2015-08-27

copyright information. 13. SUPPLEMENTARY NOTES. Enter information not included elsewhere such as: prepared in cooperation with; translation of; report...II-VI heterojunctions such as multi-color photodetectors and solar cells [2]. Mixing lattice-matched II-VI and III-V semiconductors could be an...at 77 K, further silicon oxide surface passivation can be done to suppress the surface leakage [10] in the future work. Figure 10 The dark I-V

Production of N2O in grass-clover pastures

International Nuclear Information System (INIS)

Carter, M.S.

2005-09-01

Agricultural soils are known to be a considerable source of the strong greenhouse gas nitrous oxide (N 2 O), and in soil N 2 O is mainly produced by nitrifying and denitrifying bacteria. In Denmark, grass-clover pastures are an important component of the cropping system in organic as well as conventional dairy farming, and on a European scale grass-clover mixtures represent a large part of the grazed grasslands. Biological dinitrogen (N 2 ) fixation in clover provides a major N input to these systems, but knowledge is sparse regarding the amount of fixed N 2 lost from the grasslands as N2O. Furthermore, urine patches deposited by grazing cattle are known to be hot-spots of N 2 O emission, but the mechanisms involved in the N 2 O production in urine-affected soil are very complex and not well understood. The aim of this Ph.D. project was to increase the knowledge of the biological and physical-chemical mechanisms, which control the production of N2O in grazed grass-clover pastures. Three experimental studies were conducted with the objectives of: 1: assessing the contribution of recently fixed N 2 as a source of N 2 O. 2: examining the link between N 2 O emission and carbon mineralization in urine patches. 3: investigating the effect of urine on the rates and N 2 O loss ratios of nitrification and denitrification, and evaluating the impact of the chemical conditions that arise in urine affected soil. The results revealed that only 3.2 ± 0.5 ppm of the recently fixed N 2 was emitted as N2O on a daily basis. Thus, recently fixed N released via easily degradable clover residues appears to be a minor source of N2O. Furthermore, increased N 2 O emission following urine application at rates up to 5.5 g N m -2 was not caused by enhanced denitrification stimulated by labile compounds released from scorched plant roots. Finally, the increase of soil pH and ammonium following urine application led to raised nitrification rate, which appeared to be the most important factor

Effect of fertilizer type on cadmium and fluorine concentrations in clover herbage

International Nuclear Information System (INIS)

McLaughlin, M.J.

2002-01-01

This study investigated whether changing phosphatic fertilizer type affects the accumulation of cadmium (Cd) and fluorine (F) in pasture herbage. North Carolina phosphate rock and partially acidulated fertilizers derived from this rock generally have higher Cd and F concentrations compared to single superphosphate currently manufactured in Australia. Clover herbage from sites of the National Reactive Phosphate Rock (RPR) trial was collected and analysed for concentrations of Cd (11 sites) and F (4 sites). A comparison was made between pastures fertilized with 4 rates of single superphosphate, North Carolina phosphate rock, and partially acidulated phosphate rock having Cd concentrations of 283, 481, and 420 mg Cd/kg P respectively, and 170, 271, and 274 g F/kg P respectively. One site used Hemrawein (Egypt) phosphate rock (HRP) having a Cd and F concentration of 78 mg Cd/kg P and 256 g F/kg P respectively. To help identify differences in herbage Cd concentrations between sites, unfertilised soils from each site were analyzed for total and extractable Cd contents. At one site Cd concentrations in bulk herbage (clover, grasses and weeds) were related to infestation of the pasture by capeweed (Arctotheca calendula L. Levyns). There were no significant differences between F in herbage from plots fertilized with single superphosphate, partially acidulated phosphate rock or North Carolina phosphate rock, or between sites. Concentrations of F in herbage were low, generally less than 10 mg F /kg. However, there were large differences in Cd concentrations in herbage between sites, while differences between fertilizer treatments were small in comparison. The site differences were only weakly related to total or extractable (0.01 mol/L CaCl 2 ) Cd concentrations in soil. Significant differences in Cd concentrations in clover due to fertilizer type were found at 5 sites. North Carolina phosphate rock treatments had significantly higher Cd concentrations in clover compared to

Novel fat-link fermion actions for lattice QCD

International Nuclear Information System (INIS)

Zanotti, J.; Bilson-Thompson, S.; Bonnet, F.; Leinweber, D.; Melnitchouk, W.; Williams, A.

2000-01-01

Full text: We are currently exploring new ideas for lattice fermion actions. Naive implementations of fermion actions encounter the well known fermion-doubling problem. In order to solve this problem, Wilson introduced an irrelevant (energy) dimension-five operator (the so-called Wilson term) which explicitly breaks chiral symmetry. The scaling properties of this Wilson action can be improved by introducing any number of irrelevant operators of increasing dimension which also vanish in the continuum limit. In this manner, one can improve fermion actions at finite 'a' by combining operators to eliminate O(a) and perhaps O(a 2 ) errors etc. A popular formulation of a lattice fermion action that achieves this is the Clover action which removes the O(a) error introduced by the Wilson term by introducing an additional irrelevant dimension-five operator. The Clover action can be O(a) improved to all orders in the strong coupling 'g'. While the Clover action displays excellent scaling, it is responsible for revealing the exceptional configuration problem where the quark propagator encounters singular behaviour particularly as the quark mass becomes small. Moreover, its free dispersion relation between energy and momentum is unchanged from the standard Wilson action dispersion and shows a continuum like behaviour only for relatively small momenta [F. X. Lee and D. B. Leinweber, Phys. Rev. D59, 074504 (1999), hep-lat/9711044]. Finally, significant chiral symmetry breaking is apparent as the renormalised quark mass differs significantly from the bare mass of the theory. Hence we propose a different approach to fermion action improvement. One in which the additive renormalisations become small while expressing good chiral behaviour. This can be achieved through the consideration of 'fat-link' fermion actions [T. DeGrand (the MILC collaboration, Phys. Rev. D60, 094501 (1999)]. Fat links are created by averaging or smearing links on the lattice with their nearest neighbours in

Effects of clover density on N2O emissions and plant-soil N transfers in a fertilised upland pasture

DEFF Research Database (Denmark)

Klumpp, Katja; Bloor, Juliette M. G.; Ambus, Per

2011-01-01

regression analysis revealed that water-filled pore space (WFPS) and clover dry mass were the main factors driving cumulative N2O emissions in the high clover treatment, whereas variation in cumulated N2O emissions in the low clover treatment was best explained by WFPS and grass mass. We hypothesize...

The ρ-meson light-cone distribution amplitudes from lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Braun, Vladimir M.; Bruns, Peter C.; Collins, Sara [Institut für Theoretische Physik, Universität Regensburg,Universitätsstraße 31, 93040 Regensburg (Germany); Gracey, John A. [Theoretical Physics Division, Department of Mathematical Sciences, University of Liverpool, P.O. Box 147, Liverpool, L69 3BX (United Kingdom); Gruber, Michael; Göckeler, Meinulf; Hutzler, Fabian; Pérez-Rubio, Paula; Schäfer, Andreas; Söldner, Wolfgang [Institut für Theoretische Physik, Universität Regensburg,Universitätsstraße 31, 93040 Regensburg (Germany); Sternbeck, André [Theoretisch-Physikalisches Institut, Friedrich-Schiller-Universität Jena,Max-Wien-Platz 1, 07743 Jena (Germany); Wein, Philipp [Institut für Theoretische Physik, Universität Regensburg,Universitätsstraße 31, 93040 Regensburg (Germany)

2017-04-13

We present the results of a lattice study of the normalization constants and second moments of the light-cone distribution amplitudes of longitudinally and transversely polarized ρ mesons. The calculation is performed using two flavors of dynamical clover fermions at lattice spacings between 0.060 fm and 0.081 fm, different lattice volumes up to m{sub π}L=6.7 and pion masses down to m{sub π}=150 MeV. Bare lattice results are renormalized non-perturbatively using a variant of the RI{sup ′}-MOM scheme and converted to the (MS)-bar scheme. The necessary conversion coefficients, which are not available in the literature, are calculated. The chiral extrapolation for the relevant decay constants is worked out in detail. We obtain for the ratio of the tensor and vector coupling constants f{sub ρ}{sup T}/f{sub ρ}=0.629(8) and the values of the second Gegenbauer moments a{sub 2}{sup ∥}=0.132(27) and a{sub 2}{sup ⊥}=0.101(22) at the scale μ=2 GeV for the longitudinally and transversely polarized ρ mesons, respectively. The errors include the statistical uncertainty and estimates of the systematics arising from renormalization. Discretization errors cannot be estimated reliably and are not included. In this calculation the possibility of ρ→ππ decay at the smaller pion masses is not taken into account.

Genetic variability of isoflavones in the USDA red clover core collection

Directory of Open Access Journals (Sweden)

Graziele P. Ramos

2012-11-01

Full Text Available Red clover is one of the most utilized forage in agriculture and contains many of the isoflavones known for their human health benefits. The objectives of this study were: i to quantify, using HPLC analysis, isoflavones in 77 accessions from the USDA core collection and a Brazilian line; ii to verify possible relationships depending on their origin, improvement status or maturity type and; iii to verify the seasonal variation. The isoflavone mean contents were 29.27 µg g-1 of dry material for daidzein, 163.69 µg g-1 for genistein, 11353.29 µg g-1 for formononetin and 6568.8 µg g-1 for biochanin A. Clustering was mainly influenced by the total amount of isoflavones and partially due to maturity type, improvement status and geographic origin. The seasonal evaluation demonstrated an increase of concentration during winter, and decrease during spring. These results highlighted accessions that can be used to develop new varieties with low or high isoflavones concentration.

Towards the confirmation of QCD on the lattice. Improved actions and algorithms

International Nuclear Information System (INIS)

Krieg, Stefan F.

2009-01-01

Lattice Quantum Chromodynamics has made tremendous progress over the last decade. New and improved simulation algorithms and lattice actions enable simulations of the theory with unprecedented accuracy. In the first part of this thesis, novel simulation algorithms for dynamical overlap fermions are presented. The generic Hybrid Monte Carlo algorithm is adapted to treat the singularity in the Molecular Dynamics force, to increase the tunneling rate between different topological sectors and to improve the overall volume scaling of the combined algorithm. With this new method, simulations with dynamical overlap fermions can reach smaller lattice spacings, larger volumes, smaller quark masses, and therefore higher precision than had previously been possible. The second part of this thesis is focused on a large scale simulation aiming to compute the light hadron mass spectrum. This simulation is based on a tree-level Symanzik improved gauge and tree-level improved stout-smeared Wilson clover action. The efficiency of the combination of this action and the improved simulation algorithms used allows to completely control all systematic errors. Therefore, this simulation provides a highly accurate ab initio calculation of the masses of the light hadrons, such as the proton, responsible for 95% of the mass of the visible universe, and confirms Lattice QCD in the light hadron sector. (orig.)

Towards the confirmation of QCD on the lattice. Improved actions and algorithms

Energy Technology Data Exchange (ETDEWEB)

Krieg, Stefan F.

2009-07-01

Lattice Quantum Chromodynamics has made tremendous progress over the last decade. New and improved simulation algorithms and lattice actions enable simulations of the theory with unprecedented accuracy. In the first part of this thesis, novel simulation algorithms for dynamical overlap fermions are presented. The generic Hybrid Monte Carlo algorithm is adapted to treat the singularity in the Molecular Dynamics force, to increase the tunneling rate between different topological sectors and to improve the overall volume scaling of the combined algorithm. With this new method, simulations with dynamical overlap fermions can reach smaller lattice spacings, larger volumes, smaller quark masses, and therefore higher precision than had previously been possible. The second part of this thesis is focused on a large scale simulation aiming to compute the light hadron mass spectrum. This simulation is based on a tree-level Symanzik improved gauge and tree-level improved stout-smeared Wilson clover action. The efficiency of the combination of this action and the improved simulation algorithms used allows to completely control all systematic errors. Therefore, this simulation provides a highly accurate ab initio calculation of the masses of the light hadrons, such as the proton, responsible for 95% of the mass of the visible universe, and confirms Lattice QCD in the light hadron sector. (orig.)

7 CFR 202.44 - Proceedings under section 305(b) to determine whether foreign alfalfa or red clover seed is not...

Science.gov (United States)

2010-01-01

... foreign alfalfa or red clover seed is not adapted for general agricultural use in the United States. 202... Proceedings under section 305(b) to determine whether foreign alfalfa or red clover seed is not adapted for... for the purpose of determining whether seed of alfalfa or red clover from any foreign country or...

Association of phytoplasmas and viruses with malformed clovers

Czech Academy of Sciences Publication Activity Database

Fránová, Jana; Paltrinieri, S.; Botti, S.; Šimková, Marie; Bertaccini, A.

2004-01-01

Roč. 49, č. 5 (2004), s. 617-624 ISSN 0015-5632 R&D Projects: GA AV ČR IBS5051014 Institutional research plan: CEZ:AV0Z5051902 Keywords : mycoplasma-like organismus * viruses * clovers * classification Subject RIV: EE - Microbiology, Virology Impact factor: 1.034, year: 2004

Nitrogen fertilization of grass/clover swards under cutting or grazing by dairy cows

DEFF Research Database (Denmark)

Søegaard, Karen

2009-01-01

farms over a period of three years. Nitrogen was applied at four rates (0, 75, 150, and 225 kg N year-1) with cutting or grazing regime in Year 1 and Year 2, after establishment. A spring-only application of 150 kg N was compared with four applications during the season, which was the fertilization...... affected. The results indicate different possibilities for strategic fertilization both at farm and field level, and in swards with a high clover content it demonstrates how the clover content can be used as a buffer both for maximizing the N-response and for manipulating the production profile.......Intensively managed perennial ryegrass/white clover (Lolium perenne L. and Trifolium repens L.) swards receive relatively high levels of fertilizer N, and high N surpluses can subsequently be found. The N-fertilization effects on growth, yield, and herbage quality were therefore examined on three...

PERSISTENCE ASSESSMENT OF RED CLOVER (Trifolium pratense L. IN TÂRGOVISTE PLAIN

Directory of Open Access Journals (Sweden)

D. DUNEA

2008-05-01

Full Text Available Since the most important deficiency of forage stands is the inability to maintain adequate legume participation in mixture, it is the purpose of this paper to examine persistence in red clover in Târgoviste Plain eco-climatic conditions, together with the factors that affect it. Six red clover cultivars (Napoca-Tetra, Dacia Tetra, Vesna – tetraploids; Flora, Roxana, Start – diploids and one white clover diploid cultivar (Karina were used in pure culture and in mixture (50:50 with hybrid ryegrass (Zefir – tetraploid in a randomized block design with three replicates. Ground cover assessment in early spring was a suggestive indicator of the stand persistence to define the stability and sustainability boundaries of a reliable intensive system. In the beginning of the third year of cropping, ground cover was 54.33% for tetraploid cultivars (CV = 43.25%, and 67% for diploid cultivars (CV = 6.83% in pure stands. Same ground cover average of 27% was established both for tetraploid cultivars (CV = 36.47%, and for diploid cultivars (CV = 16.97% in mixtures with hybrid ryegrass.

Effects of Titanium Dioxide Nanoparticles on Red Clover and Its Rhizobial Symbiont.

Science.gov (United States)

Moll, Janine; Okupnik, Annette; Gogos, Alexander; Knauer, Katja; Bucheli, Thomas D; van der Heijden, Marcel G A; Widmer, Franco

2016-01-01

Titanium dioxide nanoparticles (TiO2 NPs) are in consideration to be used in plant protection products. Before these products can be placed on the market, ecotoxicological tests have to be performed. In this study, the nitrogen fixing bacterium Rhizobium trifolii and red clover were exposed to two TiO2 NPs, i.e., P25, E171 and a non-nanomaterial TiO2. Growth of both organisms individually and their symbiotic root nodulation were investigated in liquid and hydroponic systems. While 23 and 18 mg l-1 of E171 and non-nanomaterial TiO2 decreased the growth rate of R. trifolii by 43 and 23% respectively, P25 did not cause effects. Shoot length of red clover decreased between 41 and 62% for all tested TiO2 NPs. In 21% of the TiO2 NP treated plants, no nodules were found. At high concentrations certain TiO2 NPs impaired R. trifolii as well as red clover growth and their symbiosis in the hydroponic systems.

Effects of Titanium Dioxide Nanoparticles on Red Clover and Its Rhizobial Symbiont.

Directory of Open Access Journals (Sweden)

Janine Moll

Full Text Available Titanium dioxide nanoparticles (TiO2 NPs are in consideration to be used in plant protection products. Before these products can be placed on the market, ecotoxicological tests have to be performed. In this study, the nitrogen fixing bacterium Rhizobium trifolii and red clover were exposed to two TiO2 NPs, i.e., P25, E171 and a non-nanomaterial TiO2. Growth of both organisms individually and their symbiotic root nodulation were investigated in liquid and hydroponic systems. While 23 and 18 mg l-1 of E171 and non-nanomaterial TiO2 decreased the growth rate of R. trifolii by 43 and 23% respectively, P25 did not cause effects. Shoot length of red clover decreased between 41 and 62% for all tested TiO2 NPs. In 21% of the TiO2 NP treated plants, no nodules were found. At high concentrations certain TiO2 NPs impaired R. trifolii as well as red clover growth and their symbiosis in the hydroponic systems.

Electric Dipole Moment of the Neutron from 2+1 Flavor Lattice QCD.

Science.gov (United States)

Guo, F-K; Horsley, R; Meissner, U-G; Nakamura, Y; Perlt, H; Rakow, P E L; Schierholz, G; Schiller, A; Zanotti, J M

2015-08-07

We compute the electric dipole moment d(n) of the neutron from a fully dynamical simulation of lattice QCD with 2+1 flavors of clover fermions and nonvanishing θ term. The latter is rotated into a pseudoscalar density in the fermionic action using the axial anomaly. To make the action real, the vacuum angle θ is taken to be purely imaginary. The physical value of dd(n) is obtained by analytic continuation. We find d(n)=-3.9(2)(9)×10(-16) θ  e cm, which, when combined with the experimental limit on d(n), leads to the upper bound |θ|≲7.4×10(-11).

Genetic variation of white clover ( Trifolium repens L.) collections ...

African Journals Online (AJOL)

amplified polymorphic DNA (RAPD) and simple sequence repeat (SSR) to investigate the genetic relationships among white clover germplasms of China, and four commercial cultivars were included for a comparison. The results revealed that the populations showed diverse morphological traits, RAPD and SSR patterns.

Production of N{sub 2}O in grass-clover pastures

Energy Technology Data Exchange (ETDEWEB)

Carter, M.S.

2005-09-01

Agricultural soils are known to be a considerable source of the strong greenhouse gas nitrous oxide (N{sub 2}O), and in soil N{sub 2}O is mainly produced by nitrifying and denitrifying bacteria. In Denmark, grass-clover pastures are an important component of the cropping system in organic as well as conventional dairy farming, and on a European scale grass-clover mixtures represent a large part of the grazed grasslands. Biological dinitrogen (N{sub 2}) fixation in clover provides a major N input to these systems, but knowledge is sparse regarding the amount of fixed N{sub 2} lost from the grasslands as N2O. Furthermore, urine patches deposited by grazing cattle are known to be hot-spots of N{sub 2}O emission, but the mechanisms involved in the N{sub 2}O production in urine-affected soil are very complex and not well understood. The aim of this Ph.D. project was to increase the knowledge of the biological and physical-chemical mechanisms, which control the production of N2O in grazed grass-clover pastures. Three experimental studies were conducted with the objectives of: 1: assessing the contribution of recently fixed N{sub 2} as a source of N{sub 2}O. 2: examining the link between N{sub 2}O emission and carbon mineralization in urine patches. 3: investigating the effect of urine on the rates and N{sub 2}O loss ratios of nitrification and denitrification, and evaluating the impact of the chemical conditions that arise in urine affected soil. The results revealed that only 3.2 {+-} 0.5 ppm of the recently fixed N{sub 2} was emitted as N2O on a daily basis. Thus, recently fixed N released via easily degradable clover residues appears to be a minor source of N2O. Furthermore, increased N{sub 2}O emission following urine application at rates up to 5.5 g N m{sup -2} was not caused by enhanced denitrification stimulated by labile compounds released from scorched plant roots. Finally, the increase of soil pH and ammonium following urine application led to raised

Soil properties and clover establishment six years after surface application of calcium-rich by-products

Energy Technology Data Exchange (ETDEWEB)

Ritchey, K.D.; Belesky, D.P.; Halvorson, J.J. [USDA ARS, Beaver, WV (US). Appalachian Farming Systems Research Center

2004-12-01

Calcium-rich soil amendments can improve plant growth by supplying Ca and reducing detrimental effects of soil acidity, but solubility and neutralizing capacity of Ca sources vary. Our objectives were to evaluate effects of calcitic dolomite and several coal combustion by-products on soil properties at various depths 6 yr after surface application and their influence on grass-clover herbage accumulation. Calcium and Mg soil amendments were surface-applied to an acidic grassland in 1993, and orchardgrass (Dactylis glomerata L.) and tall fescue (Lolium arundinaceum (Schreb.) Darbyshire) were oversown in 1994. In 1998, amendment treatment plots were split to accommodate sod seeding with red clover (Trifolium pratense L.) or white clover (T. repens L.) as well as a nonseeded control. No N fertilizer was applied after sod seeding. Six years after amendment application, reductions in soil Al and Mn and increases in Ca and pH from 4654 kg ha{sup -1} calcitic dolomite, 15 000 kg ha{sup -1} fluidized bed combustion residue, or 526 kg ha{sup -1} MgO amendment were greatest in the surface 2.5 cm while rates of gypsum as high as 32 000 kg ha{sup -1} left little residual effect except for decreases in Mg. Percentage clover in the sward tripled as pH increased from 4.3 to 5.0 while herbage mass increased 75% as clover percentage increased. Herbage mass was generally more closely correlated with properties of soil samples collected from the surface 2.5 cm than from deeper samples.

Effects of field characteristics on abundance of bumblebees (Bombus spp.) and seed yield in red clover fields

DEFF Research Database (Denmark)

Wermuth, Kirsten Haugaard; Dupont, Yoko L.

2010-01-01

Red clover is a key floral ressource for bumblebees (Bombus spp.).We here investigate variation within and among red clover fields in species richness and abundance of Bombus spp. in addition to Apis mellifera. Bumblebee individuals were grouped into the following functional groups, based on castes...

Lattice calculation of heavy-light decay constants with two flavors of dynamical quarks

International Nuclear Information System (INIS)

Bernard, C.; Datta, S.; DeGrand, T.; DeTar, C.; Gottlieb, Steven; Heller, Urs M.; McNeile, C.; Orginos, K.; Sugar, R.; Toussaint, D.

2002-01-01

We present results for f B , f B s , f D , f D s and their ratios in the presence of two flavors of light sea quarks (N f =2). We use Wilson light valence quarks and Wilson and static heavy valence quarks; the sea quarks are simulated with staggered fermions. Additional quenched simulations with nonperturbatively improved clover fermions allow us to improve our control of the continuum extrapolation. For our central values the masses of the sea quarks are not extrapolated to the physical u, d masses; that is, the central values are ''partially quenched.'' A calculation using 'fat-link clover' valence fermions is also discussed but is not included in our final results. We find, for example, f B =190(7)( -17 +24 )( -2 +11 )( -0 +8 ) MeV, f B s /f B =1.16(1)(2)(2)( -0 +4 ), f D s =241(5)( -26 +27 )( -4 +9 )( -0 +5 ) MeV, and f B /f D s =0.79(2)( -4 +5 )(3)( -0 +5 ), where in each case the first error is statistical and the remaining three are systematic: the error within the partially quenched N f =2 approximation, the error due to the missing strange sea quark and to partial quenching, and an estimate of the effects of chiral logarithms at small quark mass. The last error, though quite significant in decay constant ratios, appears to be smaller than has been recently suggested by Kronfeld and Ryan, and Yamada. We emphasize, however, that as in other lattice computations to date, the lattice u,d quark masses are not very light and chiral log effects may not be fully under control

Effects of grass-clover management and cover crops on nitrogen cycling and nitrous oxide emissions in a stockless organic crop rotation

DEFF Research Database (Denmark)

Brozyna, Michal Adam; Petersen, Søren O; Chirinda, Ngoni

2013-01-01

Nitrogen (N) supply in stockless organic farming may be improved through use of grass-clover for anaerobic digestion, producing biogas and digested manure for use as fertilizer in the crop rotation. We studied the effects of grass-clover management on N cycling, nitrous oxide (N2O) emissions...... in the rotation (spring barley, potato and winter wheat); actual digestion of grass-clover cuttings was not possible, instead digested pig manure was used as substitute for digested grass-clover. Nitrous oxide fluxes were monitored between April 2008 and May 2009. In general, application of digested manure had...

Phyto-oestrogens in herbage and milk from cows grazing whiteclover, red clover, lucerne or chicory-rich pastures

DEFF Research Database (Denmark)

Andersen, C; Nielsen, T S; Purup, S

2009-01-01

A grazing experiment was carried out to study the concentration of phyto-oestrogens in herbage for cattle and in milk during two periods (May and June). Forty-eight Danish Holstein cows were divided into four groups with four treatment diets; white clover, red clover, lucerne and chicory-rich pas...

Non-perturbative renormalization of left-left four-fermion operators in quenched lattice QCD

CERN Document Server

Guagnelli, M; Peña, C; Sint, S; Vladikas, A

2006-01-01

We define a family of Schroedinger Functional renormalization schemes for the four-quark multiplicatively renormalizable operators of the $\\Delta F = 1$ and $\\Delta F = 2$ effective weak Hamiltonians. Using the lattice regularization with quenched Wilson quarks, we compute non-perturbatively the renormalization group running of these operators in the continuum limit in a large range of renormalization scales. Continuum limit extrapolations are well controlled thanks to the implementation of two fermionic actions (Wilson and Clover). The ratio of the renormalization group invariant operator to its renormalized counterpart at a low energy scale, as well as the renormalization constant at this scale, is obtained for all schemes.

Improving Resilience of Northern Field Crop Systems Using Inter-Seeded Red Clover: A Review

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William Deen

2013-02-01

Full Text Available In light of the environmental challenges ahead, resilience of the most abundant field crop production systems must be improved to guarantee yield stability with more efficient use of nitrogen inputs, soil and water resources. Along with genetic and agronomic innovations, diversification of northern agro-ecosystems using inter-seeded legumes provides further opportunities to improve land management practices that sustain crop yields and their resilience to biotic and abiotic stresses. Benefits of legume cover crops have been known for decades and red clover (Trifolium pratense is one of the most common and beneficial when frost-seeded under winter wheat in advance of maize in a rotation. However, its use has been declining mostly due to the use of synthetic fertilizers and herbicides, concerns over competition with the main crop and the inability to fully capture red clover benefits due to difficulties in the persistence of uniform stands. In this manuscript, we first review the environmental, agronomic, rotational and economical benefits associated with inter-seeded red clover. Red clover adaptation to a wide array of common wheat-based rotations, its potential to mitigate the effects of land degradation in a changing climate and its integration into sustainable food production systems are discussed. We then identify areas of research with significant potential to impact cropping system profitability and sustainability.

Preliminary research on amino acid composition and nutritional value of clover proteins

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L. Kłyszejko-Stefanowicz

2015-06-01

Full Text Available The amino acid composition and nutritional value of 5 clover varieties including 3 Polish ones ('Gloria', 'Hruszowska', 'Skrzeszowicka' and 2 of foreign origin ('Rotra' and 'Violetta' were investigated. No significant differences in the total protein content (19.2–20.0% of dry matter as well as in qualitative amino acid composition were found among the clover varieties under examination. EAA index (Essential amino acid index calculated according to Oser for 'Gloria' and 'Hruszowska' showed the highest nutritional value was – 40. The lowest value of EAA index was found for 'Violetta' cvar. – 32, intermediate values however for Rotra and Skrzeszowicka was 37 and 36.

Analysis of the effects of pair production for the suppressed clover detector

International Nuclear Information System (INIS)

Kshetri, R.

2014-01-01

Full energy peak, single escape peak and double escape peak areas have been extracted for an escape suppressed clover detector. Results have been obtained for the single crystal and addback modes of operation as well as the active and passive suppression cases at several gamma energies. We have compared the ratio of single escape peak areas in addback mode with that of single crystal mode to study if the single escape peak gains or loses counts due to addback mode. Detailed analysis has been performed for quantifying the advantages of using addback mode and active suppression. Comparison is made for different types of clover detectors with different volumes

Molecular evolution of the Li/li chemical defence polymorphism in white clover (Trifolium repens L.).

Science.gov (United States)

Olsen, K M; Sutherland, B L; Small, L L

2007-10-01

White clover (Trifolium repens) is naturally polymorphic for cyanogenesis (hydrogen cyanide release following tissue damage). The ecological factors favouring cyanogenic and acyanogenic plants have been examined in numerous studies over the last half century, making this one of the best-documented examples of an adaptive polymorphism in plants. White clover cyanogenesis is controlled by two, independently segregating Mendelian genes: Ac/ac controls the presence/absence of cyanogenic glucosides; and Li/li controls the presence/absence of their hydrolysing enzyme, linamarase. In this study, we examine the molecular evolution and population genetics of Li as it relates to the cyanogenesis polymorphism. We report here that Li exists as a single-copy gene in plants possessing linamarase activity, and that the absence of enzyme activity in li/li plants is correlated with the absence of much or all of the gene from the white clover genome. Consistent with this finding, we confirm by reverse transcription-polymerase chain reaction that Li gene expression is absent in plants lacking enzyme activity. In a molecular population genetic analysis of Li and three unlinked genes using a worldwide sample of clover plants, we find an absence of nucleotide variation and statistically significant deviations from neutrality at Li; these findings are consistent with recent positive directional selection at this cyanogenesis locus.

White clover fractions as protein source for monogastrics - Dry matter digestibility and Protein Digestibility-Corrected Amino Acid Scores

DEFF Research Database (Denmark)

Stødkilde, Lene; Damborg, Vinni K; Jørgensen, Henry

2018-01-01

BACKGROUND: The aim was to evaluate white clover as an alternative protein source for monogastrics. White clover plant and leaves were processed using a screw-press resulting in a solid pulp and a juice from which protein was acid-precipitated. The chemical composition of all fractions...... was determined and digestibility of dry matter (DM) and protein was assessed in an experiment with growing rats. RESULTS: Protein concentrates were produced with crude protein (CP) content of 451 g/kg DM and 530 g/kg DM for white clover plant and leaves, respectively and a pulp with CP content of 313 and 374 g...

Genetic variation of white clover (Trifolium repens L.) collections ...

African Journals Online (AJOL)

STORAGESEVER

2010-05-24

May 24, 2010 ... incompatibility mechanism of disomic inheritance (Thomas,. 1987). In essence ..... Badr A, Sayed-Ahmed H, El-Shanshouri A, Watson LE (2002). Ancestors of white ... Caradus JR, Woodfield DR (1997). World checklist of ... within a natural population of white clover (Trifolium repense L). J. Ecol. 73: 615-624 ...

Growth of bermudagrass with white clover or nitrogen fertilizer

Science.gov (United States)

White clover (Trifolium repens) var ‘Durana’ was oversown into established bermudagrass (Cynodon dactylon) in 2009. Soil analysis indicated potassium (K) was low and potash at 112 and 336 kg/ha was added as main plots. Nitrogen as ammonium nitrate or an ammonium sulfate/urea blend was added as 0, 34...

Lattice site location of electrical dopant impurities in group-III nitrides

CERN Document Server

Amorim, Lígia; Temst, Kristiaan; Wahl, Ulrich

Dopants are impurities introduced in semiconductors in small quantities to tailor the material characteristics, the effects of which depend on the exact site the dopant occupies in the crystal lattice. The lattice location of impurities is, thus, crucial for the overall understanding of the semiconductor characteristics. In general, several techniques can be used to investigate the lattice site of an impurity, the most accurate and dedicated being emission channeling. However, a characteristic of this technique is that it requires the implantation of radioactive probes, usually created and accelerated in a radioactive ion beam facility. In some cases, emission channeling might however be the only technique capable to investigate the lattice sites occupied by the impurity atoms, provided an appropriate isotope for this technique can be used. For instance, the use of other methods such as Rutherford backscattering spectrometry, perturbed angular correlations, Mössbauer spectroscopy and extended X-ray absorptio...

Nitrogen transfer via VA mycorrhiza hyphae link between roots of red clover

International Nuclear Information System (INIS)

Zhang Junling; Li Xiaolin; Yang Zhifu

1997-01-01

Five compartments with a air gap was designed to examine underground N transfer via VAM hyphae link between roots of red clover. 15 N was injected into the root compartment for donor plant 4 weeks after planting. Plants were harvested 6 weeks afterwards. The experiment had four treatments: two N levels (receiver root compartment); mycorrhiza and non-mycorrhiza treatment (B compartment), and each with four replicates. It was demonstrated that there was no significant difference in 15 N abundance in receiver red clover regardless of the inoculation of mycorrhiza fungi and nitrogen fertilization. Both shoot and root dry weight of receiver plants were not affected too, however, plant P and N nutrient status got better under this condition

Cleaning the Soil from Zinc Using Red Clovers “Arimaičiai”

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Audronė Mikalajūnė

2011-02-01

Full Text Available Zinc as a nutrition element is required to plants in small quantities to maintain normal functions of metabolism mechanisms. Our work analyses the efficiency of red clovers “Arimaičiai” for cleaning zinc from the soil contaminated with zinc under laboratory conditions. Seeds were sown in three differently polluted soils: clean soil, once contaminated with zinc and periodically contaminated with zinc soil. Zinc concentration in one time contaminated soil was 45 mg/kg. After 6 months of phytoremediation, the remained zinc concentration in the soil was 3 times lower comparing with the initial concentration. It was also determined that under such conditions, the uptake of red clovers made approximately 65% of zinc. Permanent soil contamination with zinc increased concentration before phytoremediation up to 80 mg/kg. After 6 months of phytoremediation, zinc concentration was determined to be 1.9 times lower. Otherwise, the soil was permanently contaminated with larger zinc quantities and after application of which reached 300 mg/kg. In this case, following half a year of phytoremediation, zinc concentration in the soil was 1.7 times lower comparing with the initial concentration after contamination. It was determined that the uptake of red clovers made approximately 17% of zinc.Article in Lithuanian

Kinetics and optimization of red clover pulp drying

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A. A. Shevtsov

2013-01-01

Full Text Available The kinetics of the drying process conducted with bagasse red clover on an experimental dry¬er superheated steam at atmospheric pressure in the active hydrodynamic regimes were study¬ing. The rational intervals of parameter changes were obtained. The problem of optimization, which allowed allocating the optimum range of variation of the input factors according to three criteria through compromise was solved.

Salt tolerance in red clover (Trifolium pratense L.) seedlings

African Journals Online (AJOL)

Jane

2011-08-15

Aug 15, 2011 ... This study was conducted to investigate the effect of salt stress on germination of 28 red clover. (Trifolium pratense ... tolerance with the aim of improving crop plants (Zhu,. 2001) or soil .... The interaction of salinity and population in terms of PI ... in shoot growth is probably due to hormonal signals generated ...

The electric dipole moment of the neutron from 2+1 flavor lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Guo, F.K. [Bonn Univ. (Germany). Helmholtz Inst. fuer Strahlen- und Kernphysik; Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Meissner, U.G. [Bonn Univ. (Germany). Helmholtz Inst. fuer Strahlen- und Kernphysik; Forschungszentrum Juelich GmbH (Germany). Inst. for Advanced Simulation; Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Forschungszentrum Juelich (Germany). Center for Hadron Physics; Juelich Aachen Research Alliance (Germany). JARA-FAME and JARA-HPC; Nakamura, Y. [RIKEN Advanced Institute for Computational Science, Kobe (Japan); Perlt, H.; Schiller, A. [Leipzig Univ. (Germany). Inst. fuer Theoretische Physik; Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Div.; Schierholz, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Zanotti, J.M. [Adelaide Univ. (Australia). CSSM, Dept. of Physics

2015-02-15

We compute the electric dipole moment d{sub n} of the neutron from a fully dynamical simulation of lattice QCD with 2+1 flavors of clover fermions and nonvanishing theta term. The latter is rotated into the pseudoscalar density in the fermionic action using the axial anomaly. To make the action real, the vacuum angle θ is taken to be purely imaginary. The physical value of d{sub n} is obtained by analytic continuation. We find d{sub n}=-3.8(2)(9) x 10{sup -16} θ e cm, which, when combined with the experimental limit on d{sub n}, leads to the upper bound vertical stroke θ vertical stroke

S/sub n/ analysis of the TRX metal lattices with ENDF/B version III data

International Nuclear Information System (INIS)

Wheeler, F.J.

1975-01-01

Two critical assemblies, designated as thermal-reactor benchmarks TRX-1 and TRX-2 for ENDF/B data testing, were analyzed using the one-dimensional S/sub n/-theory code SCAMP. The two assemblies were simple lattices of aluminum-clad, uranium-metal fuel rods in triangular arrays with D 2 O as moderator and reflector. The fuel was low-enriched (1.3 percent 235 U), 0.387-inch in diameter and had an active height of 48 inches. The volume ratio of water to uranium was 2.35 for the TRX-1 lattice and 4.02 for TRX-2. Full-core S/sub n/ calculations based on Version III data were performed for these assemblies and the results obtained were compared with the measured values of the multiplication factors, the ratio of epithermal-to-thermal neutron capture in 238 U, the ratio of epithermal-to-thermal fission in 235 U, the ratio of 238 U fission to 235 U fission, and the ratio of capture in 238 U to fission in 235 U. Reaction rates were obtained from a central region of the full-core problems. Multigroup cross sections for the reactor calculation were obtained from S/sub n/ cell calculations with resonance self-shielding calculated using the RABBLE treatment. The results of the analyses are generally consistent with results obtained by other investigators

Estimating impact on clover-grass yield caused by traffic intensities

DEFF Research Database (Denmark)

Jørgensen, R N; Green, Ole; Kristensen, Kristian

2009-01-01

Steer and a 15 m3 Kimadan slurry tanker on two axels, was used to perform the simulated traffic treatment on the parcels. The different traffic intensities are combinations of different tire pressure (1,0 and 2,5 bar), tire load (3000 and 6000 kg), time of year and number of passes (variating from 0 to 8...... components must be determined.   The objective of this paper was to measure yield affects on clover-grass as a consequence of different traffic intensities. The experiments were carried out in the context of a full scale field trial. A 14 hectare full scale grass-clover field trial with 24 different traffic......). The harvesting procedure was preformed with a Haldrup plot harvester modified with RTK-GPS. This paper shows the initial results from measuring the yield affects References M.A. Hamza, M.A.; Anderson, W.K 2005. Soil compaction in cropping systems: A review of the nature, causes and possible solutionsRaper , R...

Lattice QCD production on commodity clusters at Fermilab

International Nuclear Information System (INIS)

Holmgren, D.

2003-01-01

We describe the construction and results to date of Fermilab's three Myrinet-networked lattice QCD production clusters (an 80-node dual Pentium III cluster, a 48-node dual Xeon cluster, and a 128-node dual Xeon cluster). We examine a number of aspects of performance of the MILC lattice QCD code running on these clusters

Joseph Clover and the cobra: a tale of snake envenomation and attempted resuscitation with bellows in London, 1852.

Science.gov (United States)

Ball, C

2010-07-01

The Industrial Revolution saw the creation of many new jobs, but probably none more curious than that of zookeeper. The London Zoological Gardens, established for members in 1828, was opened to the general public in 1847. In 1852 the "Head Keeper in the Serpent Room", Edward Horatio Girling, spent a night farewelling a friend departing for Australia. He arrived at work in an inebriated state and was bitten on the face by a cobra that he was handling in a less than sensible manner. He was taken by cab to University College Hospital where he was resuscitated by a number of doctors, including Joseph Clover then the resident medical officer to the hospital and later to become the leading anaesthetist in London. Clover recorded this event in his diary along with the resuscitation method used. The patient eventually died but his treatment created a flurry of correspondence in the medical and lay press. Interestingly, the attempted resuscitation was with bellows, which had been abandoned by the Royal Humane Society twenty years earlier Clover records other cases of resuscitation with bellows at University College Hospital during his time as a resident medical officer there (1848 to 1853). There is a casebook belonging to Joseph Clover in the Geoffrey Kaye Museum, in Melbourne. This story is one of the many interesting stories uncovered during a study of this book and Clover's other personal papers.

Assessment of dietary ratios of red clover and corn silages on milk production and milk quality in dairy cows.

Science.gov (United States)

Moorby, J M; Ellis, N M; Davies, D R

2016-10-01

Twenty-four multiparous Holstein-Friesian dairy cows were used in a replicated 3×3 Latin square changeover design experiment to test the effects of changing from corn (Zea mays) silage to red clover (Trifolium pratense) silage in graded proportions on feed intakes, milk production, and whole-body N and P partitioning. Three dietary treatments with ad libitum access to 1 of 3 forage mixtures plus a standard allowance of 4kg/d dairy concentrates were offered. The 3 treatment forage mixtures were, on a dry matter (DM) basis: (1) R10: 90% corn silage and 10% red clover silage, (2) R50: 50% corn silage and 50% red clover silage, and (3) R90: 10% corn silage and 90% red clover silage. In each of 3 experimental periods, there were 21d for adaptation to diets, and 7d for measurements. Diet crude protein intakes increased, and starch intakes decreased, as the silage mixture changed from 90% corn to 90% red clover, although the highest forage DM intakes and milk yields were achieved on diet R50. Although milk fat yields were unaffected by diet, milk protein yields were highest with the R 0250 diet. Whole-body partitioning of N was measured in a subset of cows (n=9), and both the daily amount and proportion of N consumed that was excreted in feces and urine increased as the proportion of red clover silage in the diet increased. However, the apparent efficiency of utilization of feed N for milk protein production decreased from 0.33g/g for diet R10 to 0.25g/g for diet R90. The urinary excretion of purine derivatives (sum of allantoin and uric acid) tended to increase, suggesting greater flow of microbial protein from the rumen, as the proportion of red clover silage in the diet increased, and urinary creatinine excretion was affected by diet. Fecal shedding of E. coli was not affected by dietary treatment. In conclusion, even though microbial protein flow may have been greatest from the R 0450 diet, optimum feed intakes and milk yields were achieved on a diet that contained a

Cool-season annual pastures with clovers to supplement wintering beef cows nursing calves

Directory of Open Access Journals (Sweden)

Gunter Stacey A

2012-07-01

Full Text Available Abstract In December of 3 years, 87 beef cows with nursing calves (594 ± 9.8 kg; calving season, September to November at side were stratified by body condition score, body weight, cow age, and calf gender and divided randomly into 6 groups assigned to 1 of 6 cool-season annual pastures (0.45 ha/cow that had been interseeded into a dormant common bermudagrass (Cynodon dactylon [L.] Pers./bahiagrass (Paspalum notatum Flugge sod. Pastures contained 1 of the following 3 seeding mixtures (2 pastures/mixture: 1 wheat (Triticum aestivum L. and ryegrass (Lolium multiflorum Lam., WRG, 2 wheat and ryegrass plus red clover (Trifolium pretense L., WRR, or 3 wheat and ryegrass plus white (Trifolium repens L. and crimson clovers (Trifolium incarnatum L., WRW. All groups had ad libitum access to grass hay (12% crude protein; 58% total digestible nutrients. The second week in December, cow estrous cycles were synchronized and artificially inseminated. In late December, a bull was placed with each group for 60-d. Data were analyzed with an analysis of variance using a mixed model containing treatment as the fixed effect and year as the random effect. Body weight and condition scores did not differ (P ≥ 0.27 among cows between February and June. Calf birth weights or average daily gain did not differ (P ≥ 0.17 among treatments; however, calves grazing pastures with clovers did tend (P = 0.06 to weigh more than calves grazing grass only. Weaning weight per cow exposed to a bull was greater (P = 0.02 for WRR and WRW than WRG. Cows grazing winter-annual pastures containing clovers tended to wean more calf body weight per cow exposed to a bull than cows grazing the grass only pastures.

Inhibitory potential of pure isoflavonoids, red clover, and alfalfa extracts on hemoglobin glycosylation

Directory of Open Access Journals (Sweden)

Mohsen Hosseini

2015-03-01

Full Text Available BACKGROUND: Non-enzymatic glycosylation of hemoglobin is complications of diabetes. Antioxidant system imbalance can result in the emergence of free radicals’ destructive effects in the long-term. Red clover (Trifolium pratense L. and alfalfa (Medicago sativa L. contain isoflavonoids and have antioxidant activity. This experimental study evaluated the inhibitory activity of pure isoflavonoids (daidzein and genistein, red clover and alfalfa extracts on hemoglobin glycosylation. METHODS: This study was performed in Iran. Stock solution of hydroalcoholic extracts of red clover and alfalfa in concentrations of 1 and 10 g/100 ml and stock solution of daidzein and genistein in concentrations of 250 ng, 500 ng, 25 µg and 250 µg/100 ml were prepared as case groups. Control group was without hydroalcoholic extracts of plants and pure isoflavonoids. All experiments were performed in triplicate. Hemoglobin was prepared and antioxidant activities were investigated to estimate degree of nonenzymatic hemoglobin glycosylation. RESULTS: There was no significantly difference between used extracts (extract of red clover and alfalfa and control of the hemoglobin glycosylation but using daidzein (P = 0.046, 0.029 and 0.021, respectively and genistein (P = 0.034, 0.036 and 0.028 significantly inhibited (P < 0.050 this reaction in 25 µg/100 ml, 250 and 500 ng/100 ml concentrations when compared to control. in 25 µg/100 ml, 250 ng and 500 ng/100 ml concentrations percentage of inhibition were 32, 80 and 74.5% respectively with used of daidzein and were 21, 83 and 76% respectively with consumption of genistein. CONCLUSION: According to decrease of glycation of hemoglobin with isoflavonoids, two used plant in this study containing isoflavonoid may be useful on diabetes.   

Enchytraeids as indicator of soil quality in temporary organic grass-clover leys under contrasting management

DEFF Research Database (Denmark)

Maraldo, Kristine; Schmelz, Rüdiger; Larsen, Thomas

2015-01-01

One objective in organic farming is to sustain the quality of the soil resource. Because enchytraeids are an important soil faunal component, they stand as bioindicators of soil quality. We tested this candidature in a field experiment on loamy sand soil with 1- and 4-year old grass-clover leys...... interactions among soil physical, chemical and biological properties suggest that enchytraeid abundance is not a feasible stand-alone indicator of management impacts on soil quality in temporary grass-clover leys but may candidate as one of several biological key parameters in more comprehensive soil quality...

A survey of the invertebrates feeding on living clover roots (Trifolium repens L.) using 32P as a radiotracer

International Nuclear Information System (INIS)

Baylis, J.P.; Cherrett, J.M.; Ford, J.B.

1986-01-01

Clover roots were labelled in the field with 32 P and the radioactive soil fauna were detected by autoradiography. The animals which consumed labelled clover roots were, in order of importance, earthworms (Aporrectodea longa, A. caliginosa and Lumbricus rubellus), weevil larvae, dipteran larvae (Bibio marci) and a few Collembola (family: Entomobryidae). (author)

Results for the η' mass from two-flavour lattice QCD

International Nuclear Information System (INIS)

Lesk, V.I.; Aoki, S.; Burkhalter, R.; Fukugita, M.; Ishikawa, K.I.; Ishizuka, N.; Iwasaki, Y.; Kanay, K.; Kaneko, T.; Kuramashi, Y.; Okawa, M.; Taniguchi, Y.; Ukawa, A.; Umeda, T.; Yoshie, T.

2003-01-01

We present results for the mass of the η' meson for two-flavor lattice QCD in the continuum limit, calculated on the CP-PACS computer, using an RG-improved gauge action and clover fermion action with tadpole-improved c sw . Measurements are made at three couplings corresponding to a ∼ 0.22, 0.16, 0.11 fm for four quark masses corresponding to m π /m ρ ∼ 0.8, 0.75, 0.7, 0.6. The two-loop diagrams are evaluated using a noisy source method. Quark smearing for both one- and two- loop diagrams is successfully applied to obtain ground state signals in the η' channel. We obtain m η' =0.960(87) -0.286 +0.036 in the continuum limit, where the second error represents the systematic uncertainty coming from varying the functional form for chiral and continuum extrapolations

White clover fractions as protein source for monogastrics: dry matter digestibility and protein digestibility-corrected amino acid scores.

Science.gov (United States)

Stødkilde, Lene; Damborg, Vinni K; Jørgensen, Henry; Laerke, Helle N; Jensen, Søren K

2018-05-01

The present study aimed to evaluate the use of white clover as an alternative protein source for monogastrics. White clover plant and leaves were processed using a screw-press resulting in a solid pulp and a juice from which protein was acid-precipitated. The chemical composition of all fractions was determined and digestibility of dry matter (DM) and protein was assessed in an experiment with growing rats. Protein concentrates were produced with crude protein (CP) contents of 451 g kg -1 and 530 g kg -1 DM for white clover plant and leaves, respectively, and a pulp with CP contents of 313 and 374 g kg -1 DM from plant and leaves, respectively. The amino acid composition ranged from 4.72 to 6.49 g per 16 g of nitrogen (N) for lysine, 1.82-2.6 g per 16 g N for methionine and cysteine, and 3.66-5.24 g per 16 g N for threonine. True faecal digestibility of protein varied from 0.81 to 0.88, whereas DM digestibility was in the range 0.72-0.80. Methionine and cysteine were found to be limiting in all fractions, regardless of the reference group used. A high digestibility of white clover protein was found irrespective of the physical fractionation. Together with a well-balanced amino acid composition, this makes white clover a promising protein source for monogastrics. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Investigation of Amino Acids As Herbicides for Control of Orobanche minor Parasitism in Red Clover.

Science.gov (United States)

Fernández-Aparicio, Mónica; Bernard, Alexandre; Falchetto, Laurent; Marget, Pascal; Chauvel, Bruno; Steinberg, Christian; Morris, Cindy E; Gibot-Leclerc, Stephanie; Boari, Angela; Vurro, Maurizio; Bohan, David A; Sands, David C; Reboud, Xavier

2017-01-01

Certain amino acids induce inhibitory effects in plant growth due to feedback inhibition of metabolic pathways. The inhibition patterns depend on plant species and the plant developmental stage. Those amino acids with inhibitory action on specific weeds could be utilized as herbicides, however, their use for weed control has not been put into practice. Orobanche minor is a weed that parasitizes red clover. O. minor germination is stimulated by clover root exudates. The subsequent seedling is an obligated parasite that must attach quickly to the clover root to withdraw its nutrients. Early development of O. minor is vulnerable to amino acid inhibition and therefore, a series of in vitro , rhizotron, and field experiments were conducted to investigate the potential of amino acids to inhibit O. minor parasitism. In in vitro experiments it was found that among a collection of 20 protein amino acids, lysine, methionine and tryptophan strongly interfere with O. minor early development. Field research confirmed their inhibitory effect but revealed that methionine was more effective than lysine and tryptophan, and that two successive methionine applications at 308 and 543 growing degree days inhibited O. minor emergence in red clover up to 67%. We investigated additional effects with potential to influence the practical use of amino acids against broomrape weeds, whether the herbicidal effect may be reversible by other amino acids exuded by host plants or may be amplified by inducing host resistance barriers against O. minor penetration. This paper suggests that amino acids may have the potential to be integrated into biorational programs of broomrape management.

Investigation of Amino Acids As Herbicides for Control of Orobanche minor Parasitism in Red Clover

Directory of Open Access Journals (Sweden)

Mónica Fernández-Aparicio

2017-05-01

Full Text Available Certain amino acids induce inhibitory effects in plant growth due to feedback inhibition of metabolic pathways. The inhibition patterns depend on plant species and the plant developmental stage. Those amino acids with inhibitory action on specific weeds could be utilized as herbicides, however, their use for weed control has not been put into practice. Orobanche minor is a weed that parasitizes red clover. O. minor germination is stimulated by clover root exudates. The subsequent seedling is an obligated parasite that must attach quickly to the clover root to withdraw its nutrients. Early development of O. minor is vulnerable to amino acid inhibition and therefore, a series of in vitro, rhizotron, and field experiments were conducted to investigate the potential of amino acids to inhibit O. minor parasitism. In in vitro experiments it was found that among a collection of 20 protein amino acids, lysine, methionine and tryptophan strongly interfere with O. minor early development. Field research confirmed their inhibitory effect but revealed that methionine was more effective than lysine and tryptophan, and that two successive methionine applications at 308 and 543 growing degree days inhibited O. minor emergence in red clover up to 67%. We investigated additional effects with potential to influence the practical use of amino acids against broomrape weeds, whether the herbicidal effect may be reversible by other amino acids exuded by host plants or may be amplified by inducing host resistance barriers against O. minor penetration. This paper suggests that amino acids may have the potential to be integrated into biorational programs of broomrape management.

Genetic variations between two ecotypes of Egyptian clover by inter ...

African Journals Online (AJOL)

Aghomotsegin

2015-06-10

Jun 10, 2015 ... Four Egyptian clover (Trifolium alexandrinum L) cultivars representing two ecotypes were used in the present study. Fahl cultivar is prevalent in whole Egypt and is good for single cut as it has poor regeneration ability, whereas Serw1, Giza6 and Gemmiza1 give 5-6 cuts of good fodder. Techniques based ...

Relationship between nitrogen cycling and nitrous oxide emission in grass-clover pasture

OpenAIRE

Ambus, P.

2005-01-01

The paper reports on a work assessing the relationship between gross N transformations in grass-clover soils and emissions of nitrous oxide. By this manner, the source strength of the biogenic processes responsible for nitrous oxide production is evaluated.

Phenotypic and genetic characterization of wildland collections of western and Searls prairie clovers for rangeland revegetation in the western USA

Science.gov (United States)

Kishor Bhattarai

2010-01-01

Western prairie clover [Dalea ornata (Douglas ex Hook.) Eaton & J. Wright] is a perennial legume that occurs in the northern Great Basin, Snake River Basin, and southern Columbia Plateau, whereas Searls prairie clover [Dalea searlsiae (A. Gray) Barneby], also a perennial legume, occurs in the southern Great Basin and surrounding areas. Understanding the genetic and...

Influence of arbuscular mycorrhizae on biomass production and nitrogen fixation of berseem clover plants subjected to water stress.

Directory of Open Access Journals (Sweden)

Sergio Saia

Full Text Available Several studies, performed mainly in pots, have shown that arbuscular mycorrhizal symbiosis can mitigate the negative effects of water stress on plant growth. No information is available about the effects of arbuscular mycorrhizal symbiosis on berseem clover growth and nitrogen (N fixation under conditions of water shortage. A field experiment was conducted in a hilly area of inner Sicily, Italy, to determine whether symbiosis with AM fungi can mitigate the detrimental effects of drought stress (which in the Mediterranean often occurs during the late period of the growing season on forage yield and symbiotic N2 fixation of berseem clover. Soil was either left under water stress (i.e., rain-fed conditions or the crop was well-watered. Mycorrhization treatments consisted of inoculation of berseem clover seeds with arbuscular mycorrhizal spores or suppression of arbuscular mycorrhizal symbiosis by means of fungicide treatments. Nitrogen biological fixation was assessed using the 15N-isotope dilution technique. Arbuscular mycorrhizal symbiosis was able to mitigate the negative effect of water stress on berseem clover grown in a typical semiarid Mediterranean environment. In fact, under water stress conditions, arbuscular mycorrhizal symbiosis resulted in increases in total biomass, N content, and N fixation, whereas no effect of crop mycorrhization was observed in the well-watered treatment.

Influence of arbuscular mycorrhizae on biomass production and nitrogen fixation of berseem clover plants subjected to water stress.

Science.gov (United States)

Saia, Sergio; Amato, Gaetano; Frenda, Alfonso Salvatore; Giambalvo, Dario; Ruisi, Paolo

2014-01-01

Several studies, performed mainly in pots, have shown that arbuscular mycorrhizal symbiosis can mitigate the negative effects of water stress on plant growth. No information is available about the effects of arbuscular mycorrhizal symbiosis on berseem clover growth and nitrogen (N) fixation under conditions of water shortage. A field experiment was conducted in a hilly area of inner Sicily, Italy, to determine whether symbiosis with AM fungi can mitigate the detrimental effects of drought stress (which in the Mediterranean often occurs during the late period of the growing season) on forage yield and symbiotic N2 fixation of berseem clover. Soil was either left under water stress (i.e., rain-fed conditions) or the crop was well-watered. Mycorrhization treatments consisted of inoculation of berseem clover seeds with arbuscular mycorrhizal spores or suppression of arbuscular mycorrhizal symbiosis by means of fungicide treatments. Nitrogen biological fixation was assessed using the 15N-isotope dilution technique. Arbuscular mycorrhizal symbiosis was able to mitigate the negative effect of water stress on berseem clover grown in a typical semiarid Mediterranean environment. In fact, under water stress conditions, arbuscular mycorrhizal symbiosis resulted in increases in total biomass, N content, and N fixation, whereas no effect of crop mycorrhization was observed in the well-watered treatment.

Assessment of Protective Effect of Some Modern Agrochemicals against Ozone-Induced Stress in Sensitive Clover and Tobacco Cultivars

OpenAIRE

Blum, Oleg; Didyk, Nataliya; Pavluchenko, Nataliya; Godzik, Barbara

2011-01-01

Some modern agrochemicals with antioxidant potential were tested for their protective effect against ozone injury using clover and tobacco ozone-sensitive cultivars as model plants subjected to ambient ozone at two sites (Kyiv city in Ukraine and Szarów village in Poland). All used agrochemicals showed partial protective effects against ozone injury on clover and tobacco. Conducted studies confirmed the effectiveness of modern fungicides belonging to strobilurin group as protectants of sensit...

Crystallization and preliminary X-ray diffraction analysis of red clover necrotic mosaic virus

International Nuclear Information System (INIS)

Martin, Stanton L.; Guenther, Richard H.; Sit, Tim L.; Swartz, Paul D.; Meilleur, Flora; Lommel, Steven A.; Rose, Robert B.

2010-01-01

Virions of red clover necrotic mosaic virus have been purified and crystallized. The space group was determined to be I23, with unit-cell parameter a = 377.8 Å. The crystals diffracted to 4 Å resolution. Red clover necrotic mosaic virus (RCNMV) is a species that belongs to the Tombusviridae family of plant viruses with a T = 3 icosahedral capsid. RCNMV virions were purified and were crystallized for X-ray analysis using the hanging-drop vapor-diffusion method. Self-rotation functions and systematic absences identified the space group as I23, with two virions in the unit cell. The crystals diffracted to better than 4 Å resolution but were very radiation-sensitive, causing rapid decay of the high-resolution reflections. The data were processed to 6 Å in the analysis presented here

Cumulative effects of white clover residues on the changes in soil ...

African Journals Online (AJOL)

STORAGESEVER

2009-05-18

May 18, 2009 ... The residual effects of white clover on soil properties indicated a significant increase in saturation percentage (17–23%) and .... determined by leaching the soil with KCl followed by extraction of ...... accumulation, and oil quality of French basil. ... of the Final Workshop of the Farming System Integrated Pest.

Effect of red clover on the microbial transformation of phenanthrene and octadecane in the soil

Science.gov (United States)

Nazarov, A. V.; Shestakova, E. A.; Anan'yina, L. N.

2017-08-01

The influence of red clover ( Trifolium pratense L.) plants on the decomposition of phenanthrene and octadecane in the soil has been studied. Effect of plant root mass on the abundance of hydrocarbondegrading bacteria, the composition of their communities, and the degradation of hydrocarbons in the soil has been revealed. Changes in the taxonomic composition of hydrocarbon-degrading bacteria under the effect of red clover are characterized by an increase in the abundance of species from the genera Acinetobacter, Kaistia, Novosphingobium, Pseudomonas, and Xanthomonas. A positive effect of the studied microbial-plant association on the degradation of octadecane and especially phenanthrene in the soil has been revealed.

Transcription of Biotic Stress Associated Genes in White Clover (Trifolium repens L.) Differs in Response to Cyst and Root-Knot Nematode Infection.

Science.gov (United States)

Islam, Afsana; Mercer, Chris F; Leung, Susanna; Dijkwel, Paul P; McManus, Michael T

2015-01-01

The transcription of four members of the Kunitz proteinase inhibitor (KPI) gene family of white clover (Trifolium repens L.), designated as Tr-KPI1, Tr-KPI2, Tr-KPI4 and Tr-KPI5, was investigated at both local infection (roots) and systemic (leaf tissue) sites in white clover in response to infection with the clover root knot nematode (CRKN) Meloidogyne trifoliophila and the clover cyst nematode (CCN) Heterodera trifolii. Invasion by the CRKN resulted in a significant decrease in transcript abundance of Tr-KPI4 locally at both 4 days post-infection (dpi) and at 8 dpi, and an increase in transcription of Tr-KPI1 systemically at 8 dpi. In contrast, an increase in transcript abundance of all four Tr-KPI genes locally at 4 and 8 dpi, and an increase of Tr-KPI1, Tr-KPI2, and Tr-KPI5 at 8 dpi systemically was observed in response to infection with the CCN. Challenge of a resistant (R) genotype and a susceptible (S) genotype of white clover with the CCN revealed a significant increase in transcript abundance of all four Tr-KPI genes locally in the R genotype, while an increase in abundance of only Tr-KPI1, Tr-KPI2, and Tr-KPI5 was observed in the S genotype, and only at 4 dpi. The transcript abundance of a member of the1-AMINOCYCLOPROPANE-1-CARBOXYLATE (ACC) SYNTHASE gene family from white clover (Tr-ACS1) was significantly down-regulated locally in response to CRKN infection at 4 and 8 dpi and at 4 dpi, systemically, while abundance increased locally and systemically at 8 dpi in response to CCN challenge. Conversely, the abundance of the jasmonic acid (JA) signalling gene, CORONATINE-INSENSITIVE PROTEIN 1 from white clover (Tr-COI1) increased significantly at 8 dpi locally in response to CRKN infection, but decreased at 8 dpi in response to CCN infection. The significance of this differential regulation of transcription is discussed with respect to differences in infection strategy of the two nematode species.

Effect of Plant Density on Growth Characteristics and Yield of Summer Savory (Satureja hortensis L. and Persian Clover (Trifolium resupinatum L. Intercropping

Directory of Open Access Journals (Sweden)

f Hassanzadeh Aval

2012-02-01

Full Text Available Abstract In order to evaluate intercropping of summer savory (Satureja hortensis L. and Persian clover (Trifolium resupinatum L., an experiment was conducted in the Agricultural Research Station of Ferdowsi University of Mashhad in 2004 growing season. Treatments were sole cropping of Persian clover (eight rows, double-row intercropping of Persian clover and summer savory with 27, 40 and 80 plants.m-2 (eight rows and sole cropping of summer savory with 27, 40 and 80 plants m-2 (eight rows. For this purpose a complete randomized block design with 4 replications was used. Shoot and stem percentage of summer savory in sole crop treatments were significantly higher than in intercrop. In sole crop treatments, these parameters decreased by increasing plant density, in contrast to the intercrop. Leaf percentage and leaf and flower to stem ratio of summer savory in sole crop treatments were significantly lower than in intercrop. In sole crop treatments, these parameters were increased by increasing plant density, in contrast to intercrop. Effect of different treatments on essential oil percentage of summer savory was not significant. In sole cropping of Persian clover treatment, dry weight of vegetative organs and stem percentage of Persian clover in the first harvest, was lower than other treatments. By decreasing plant density these parameters were decreased in intercropping. In the second and third harvests a reversed pattern was observed. The highest Area Time Equivalent Ratio was obtained in intercropping of persian clover and summer savory with 27 plants.m-2. Keywords: Intercropping, Plant density, Satureja hortensis, Trifolium resupinatum, Essential oil percentage, Area Time Equivalent Ratio

Analysis of the soil food web structure under grass and grass clover

NARCIS (Netherlands)

Eekeren, van N.J.M.; Smeding, F.W.; Vries, de F.T.; Bloem, J.

2006-01-01

The below ground biodiversity of soil organisms plays an important role in the functioning of the the soil ecosystem, and consequently the above ground plant production. The objective of this study is to investigate the effect of grass or grass-clover in combination with fertilisation on the soil

Effects of titanium dioxide nanoparticles on red clover and its rhizobial symbiont

NARCIS (Netherlands)

Moll, Janine; Okupnik, Annette; Gogos, Alexander; Knauer, Katja; Bucheli, Thomas D.; Van Der Heijden, Marcel G A; Widmer, Franco

2016-01-01

Titanium dioxide nanoparticles (TiO2 NPs) are in consideration to be used in plant protection products. Before these products can be placed on the market, ecotoxicological tests have to be performed. In this study, the nitrogen fixing bacterium Rhizobium trifolii and red clover were exposed to two

Characterisation of a compton suppressed clover detector for high energy gamma rays (5 MeV ≤ E ≤ 11 MeV)

International Nuclear Information System (INIS)

Saha Sarkar, M.; Kshetri, Ritesh; Raut, Rajarshi; Mukherjee, A.; Goswami, A.; Ray, S.; Basu, P.; Majumder, H.; Bhattacharya, S.; Dasmahapatra, B.; Sinha, Mandira; Ray, Maitreyee

2004-01-01

The Clover detectors in their add back mode have been seen to be excellent tools for detecting high energy gamma rays (≥ 2 MeV). Recently studies were carried out on the characteristics of a Compton suppressed Clover germanium detector up to 5 MeV using a radioactive 66 Ga (T 1/2 =9.41 h) source for the first time

Towards integrated pest management in red clover seed production.

Science.gov (United States)

Lundin, Ola; Rundlöf, Maj; Smith, Henrik G; Bommarco, Riccardo

2012-10-01

The development of integrated pest management is hampered by lack of information on how insect pest abundances relate to yield losses, and how pests are affected by control measures. In this study, we develop integrated pest management tactics for Apion spp. weevils (Coleoptera: Brentidae) in seed production of red clover, Trifolium pratense L. We tested a method to forecast pest damage, quantified the relationship between pest abundance and yield, and evaluated chemical and biological pest control in 29 Swedish red clover fields in 2008 and 2011. Pest inflorescence abundance, which had a highly negative effect on yield, could be predicted with pan trap catches of adult pests. In 2008, chemical control with typically one application of pyrethroids was ineffective both in decreasing pest abundances and in increasing yields. In 2011, when chemical control included applications of the neonicotinoid thiacloprid, pest abundances decreased and yields increased considerably in treated field zones. A post hoc analysis indicated that using pyrethroids in addition to thiacloprid was largely redundant. Infestation rates by parasitoids was higher and reached average levels of around 40% in insecticide treated field zones in 2011, which is a level of interest for biological pest control. Based on the data presented, an economic threshold for chemical control is developed, and guidelines are provided on minimum effective chemical pest control.

Forbs enhance productivity of unfertilised grass-clover leys and support low-carbon bioenergy

DEFF Research Database (Denmark)

Cong, Wen-Feng; Jing, Jingying; Rasmussen, Jim

2017-01-01

Intensively managed grasslands are dominated by highly productive grass-clover mixtures. Increasing crop diversity by inclusion of competitive forbs may enhance biomass production and sustainable biofuel production. Here we examined if one or all of three forbs (chicory, Cichorium intybus L.; car...

Accelerating Lattice QCD Multigrid on GPUs Using Fine-Grained Parallelization

Energy Technology Data Exchange (ETDEWEB)

Clark, M. A. [NVIDIA Corp., Santa Clara; Joó, Bálint [Jefferson Lab; Strelchenko, Alexei [Fermilab; Cheng, Michael [Boston U., Ctr. Comp. Sci.; Gambhir, Arjun [William-Mary Coll.; Brower, Richard [Boston U.

2016-12-22

The past decade has witnessed a dramatic acceleration of lattice quantum chromodynamics calculations in nuclear and particle physics. This has been due to both significant progress in accelerating the iterative linear solvers using multi-grid algorithms, and due to the throughput improvements brought by GPUs. Deploying hierarchical algorithms optimally on GPUs is non-trivial owing to the lack of parallelism on the coarse grids, and as such, these advances have not proved multiplicative. Using the QUDA library, we demonstrate that by exposing all sources of parallelism that the underlying stencil problem possesses, and through appropriate mapping of this parallelism to the GPU architecture, we can achieve high efficiency even for the coarsest of grids. Results are presented for the Wilson-Clover discretization, where we demonstrate up to 10x speedup over present state-of-the-art GPU-accelerated methods on Titan. Finally, we look to the future, and consider the software implications of our findings.

Modelling Gene Flow between Fields of White Clover with Honeybees as Pollen Vectors

DEFF Research Database (Denmark)

Løjtnant, Christina; Boelt, Birte; Clausen, Sabine Karin

2012-01-01

The portion-dilution model is a parametric restatement of the conventional view of animal pollination; it predicts the level of pollinator-mediated gene dispersal. In this study, the model was applied to white clover (Trifolium repens) and its most frequent pollinator, the honeybee (Apis mellifera......). One of the three parameters in the portion-dilution model is the mean number of flowers a pollinator visits in one foraging bout. An alternative method to estimate this parameter was developed that was not depending on pollinator hive-seeking behaviour. The new estimation method, based on nectar......% with an estimated 95% percentile of 70%. The results show that the European Union threshold limit of 0.9% GM admixture for food and feed will likely be exceeded at times and especially organic farmers that do not accept GM admixture and often have clover and clover–grass fields might face challenges with admixture...

Effects of field characteristics on abundance of bumblebees (Bombus spp.) and seed yield in red clover fields

DEFF Research Database (Denmark)

Wermuth, Kirsten Haugaard; Dupont, Yoko L.

2010-01-01

Red clover is a key floral ressource for bumblebees (Bombus spp.).We here investigate variation within and among red clover fields in species richness and abundance of Bombus spp. in addition to Apis mellifera. Bumblebee individuals were grouped into the following functional groups, based on castes...... and tongue length: (1) all queens, (2) all workers, (3) short-tongued workers and (4) long-tongued workers. In 14 study fields, no spatial or diurnal within-field differences were found in abundances of bee groups. However, seasonal differences were detected. On average 6.3±0.6 Bombus spp. were observed...

Environmental Impact Research Program: White Clover (Trifolium repens). Section 7.3.5, US Army Corps of Engineers Wildlife Resources Management Manual.

Science.gov (United States)

1986-07-01

types where they are common (Kohn and Mooty 1971). Rumen analyses of white-tailed deer in Montana showed that forbs comprised 80% of summer samples...frequency of occurrence in deer rumens collected from January through March in the Northern Black Hills. Bluegrass- white clover meadows are also...CAUTIONS AND LIMITATIONS White clover, like most legumes, occasionally causes bloat in animals, particularly cattle and sheep that have overfilled

Effects of oil sands effluent on cattail and clover: photosynthesis and the level of stress proteins

Energy Technology Data Exchange (ETDEWEB)

Crowe, A.U.; Han, B.; Kermode, A.R.; Bendell-Young, L.I.; Plant, A.L. [Simon Fraser University, Burnaby (Canada). Dept. of Biological Sciences

2001-07-01

The oil sands industry located in northeastern Alberta, Canada, generates large volumes of effluent characterized by a high level of dissolved ions and naphthenic acids. The dikes used to store the effluent seep, creating wetlands which are subsequently invaded by obligate wetland flora such as cattail (Typha latifolia L.). The appearance of these wetlands prompted the oil sands industry to consider wetlands as part of their reclamation strategy. However, to ensure long-term viability of such wetlands, the response of the flora to the industrial effluent needed to be determined. To this end, apparent photosynthesis (APS), the level of ribulose-1,5-bisphosphate carboxylase (RuBisCo) large subunit, dehydrin-related polypeptides, and protein disulphide isomerase (PDI) were evaluated in cattail and alsike clover plants (Trifolium hybridum L.) exposed to the oil sands effluent. APS measured in plants impacted by oil sands effluent was significantly higher than that of plants in the non-impacted off-site location. Among the on-site locations, plants growing in the natural wetlands site had higher APS compared to all other sites. The level of RuBisCo was not increased in cattail or clover growing in effluent-contaminated sites indicating that enhanced photosynthesis was not due to greater levels of this enzyme. Dehydrin-related polypeptides were detected only in the roots of cattail and were absent in clover. The polypeptide profile was altered in cattail exposed to oil sands effluent indicating that they were responding to an osmotic stress. The level of PDI was unaffected in the leaves of cattail regardless of the nature of the effluent to which they were exposed. Overall, the data indicate that cattail and clover are adapted to the oil sands effluent, although further studies are needed to assess their long-term ability to survive in the presence of this anthropogenic stress. (Author)

The "clover technique" as a novel approach for correction of post-traumatic tricuspid regurgitation.

Science.gov (United States)

Alfieri, O; De Bonis, M; Lapenna, E; Agricola, E; Quarti, A; Maisano, F

2003-07-01

To describe a novel technique, named "clover," to correct complex post-traumatic tricuspid valve lesions. Five patients with severe post-traumatic tricuspid insufficiency underwent valve reconstruction with the clover technique, a new surgical approach that consists of stitching together the middle point of the free edges of the tricuspid leaflets, producing a clover-shaped valve. The mechanism of tricuspid regurgitation was complex in all patients, and right ventricular function was always moderately to severely depressed. An echocardiographic study was performed after cardiopulmonary bypass, at discharge, and at follow-up. Cardiopulmonary bypass time was 32 +/- 6.3 minutes and crossclamp time was 23 +/- 7.4. There was no hospital mortality or morbidity. Intraoperative transesophageal and predischarge transthoracic echocardiography showed perfect results in all patients. No late deaths occurred. At the latest follow-up, extending to 14.2 months (mean 11.3; median 12.4), all patients were asymptomatic (New York Heart Association class I) with trivial (2 patients) or no residual regurgitation (3 patients) on 2-dimensional echocardiogram. No transvalvular gradient was revealed in any patient. A significant reduction of the right ventricular end-diastolic dimensions was noted as well (from 54 +/- 7.1 mm to 40 +/- 7.5 mm, P tricuspid valve repair in case of severe traumatic tricuspid valve insufficiency, leading to very satisfactory mid-term results even in the presence of complex lesions or dilatation and deterioration of the right ventricle.

Honeybees tolerate cyanogenic glucosides from clover nectar and flowers

DEFF Research Database (Denmark)

Lecocq, Antoine; Green, Amelia Ann; Pinheiro de Castro, Érika Cristina

2018-01-01

Honeybees (Apis mellifera) pollinate flowers and collect nectar from many important crops. White clover (Trifolium repens) is widely grown as a temperate forage crop, and requires honeybee pollination for seed set. In this study, using a quantitative LC-MS (Liquid Chromatography-Mass Spectrometry...... indicates that plant secondary metabolites found in nectar may protect pollinators from disease or predators. In a laboratory survival study with chronic feeding of secondary metabolites, we show that honeybees can ingest the cyanogenic glucosides linamarin and amygdalin at naturally occurring...

NUTRITIVE VALUES OF SOME ANNUAL CLOVERS (Trifolium sp. AT DIFFERENT GROWTH STAGES

Directory of Open Access Journals (Sweden)

A TEKELI

2006-05-01

Full Text Available This study was conducted between the years of 2001-2002 in the experimental area and laboratory of Field Crops Department of Agriculture Faculty in Trakya University, Tekirdağ (Turkey. Five different clovers [Persian (Trifolium resupinatum L. var. majus Boiss., Mediterranean (T. spumosum L., narrow-leaved (T. angustifolium L., hedgehog (T. echinatum M. Bieb. and lappa (T. lappaceum L. clovers] were used. Each plot consisted of 8 rows with a length of 5 m. Row spacing of 30 cm and sowing rate of 10 kg ha-1 were used. Sowing times were on 2.25.2001 and on 2.28.2002. Plots were not irrigated and fertilized after sown and harvest. One cut was taken in both years at 4 growing stages such as pre-bud, pre-bloom, 50% bloom and full-bloom. The central 1 m-2 sections was cut at ground level for dry matter. Approximately 500g samples were dried at 55 °C for 24 hours and stored for one day at room temperature then found dry matter. Crude protein (% was determined by Kjeldahl method.

The performance of a white clover-based dairy system in comparison with a grass/fertiliser-N system. II. Animal production, economics and environment

NARCIS (Netherlands)

Schils, R.L.M.; Boxem, T.; Jagtenberg, C.J.; Verboom, M.C.

2000-01-01

The performance of a white clover based dairy system in comparison with a grass/fertiliser-N system was studied during three years. Both systems had 59 cows, plus young stock, on an area of 40.6 ha for grass/clover and 34.4 ha for grass/fertiliser-N. During the grazing season, the cows in both

Searls prairie clover (Dalea searlsiae) for rangeland revegetation: Phenotypic and genetic evaluations

Science.gov (United States)

Kishor Bhattarai; Shaun Bushman; Douglas A. Johnson; John G. Carman

2011-01-01

Few North American legumes are available for use in rangeland revegetation in the western USA, but Searls prairie clover [Dalea searlsiae (A. Gray) Barneby] is one that holds promise. Commercial-scale seed production of this species could address the issues of unreliable seed availability and high seed costs associated with its wildland seed collection. To evaluate its...

Nucleon electromagnetic form factors using lattice simulations at the physical point

International Nuclear Information System (INIS)

Alexandrou, C.; Cyprus Univ., Nicosia; Constantinou, M.; Hadjiyiannakou, K.; Kallidonis, C.; Koutsou, G.; Jansen, K.; Vaquero Aviles-Casco, A.

2017-01-01

We present results for the nucleon electromagnetic form factors using an ensemble of maximally twisted mass clover-improved fermions with pion mass of about 130 MeV. We use multiple sink-source separations and three analysis methods to probe ground-state dominance. We evaluate both the connected and disconnected contributions to the nucleon matrix elements. We find that the disconnected quark loop contributions to the isoscalar matrix elements are small giving an upper bound of up to 2% of the connected and smaller than its statistical error. We present results for the isovector and isoscalar electric and magnetic Sachs form factors and the corresponding proton and neutron form factors. By fitting the momentum dependence of the form factors to a dipole form or to the z-expansion we extract the nucleon electric and magnetic radii, as well as, the magnetic moment. We compare our results to experiment as well as to other recent lattice QCD calculations.

Nucleon electromagnetic form factors using lattice simulations at the physical point

Energy Technology Data Exchange (ETDEWEB)

Alexandrou, C. [The Cyprus Institute, Nicosia (Cyprus). Computation-based Science and Technology Research Center; Cyprus Univ., Nicosia (Cyprus). Dept. of Physics; Constantinou, M. [Temple Univ., Philadelphia, PA (United States). Dept. of Physics; Hadjiyiannakou, K.; Kallidonis, C.; Koutsou, G. [The Cyprus Institute, Nicosia (Cyprus). Computation-based Science and Technology Research Center; Jansen, K. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Vaquero Aviles-Casco, A. [Utah Univ., Salt Lake City, UT (United States). Dept. of Physics and Astronomy

2017-09-20

We present results for the nucleon electromagnetic form factors using an ensemble of maximally twisted mass clover-improved fermions with pion mass of about 130 MeV. We use multiple sink-source separations and three analysis methods to probe ground-state dominance. We evaluate both the connected and disconnected contributions to the nucleon matrix elements. We find that the disconnected quark loop contributions to the isoscalar matrix elements are small giving an upper bound of up to 2% of the connected and smaller than its statistical error. We present results for the isovector and isoscalar electric and magnetic Sachs form factors and the corresponding proton and neutron form factors. By fitting the momentum dependence of the form factors to a dipole form or to the z-expansion we extract the nucleon electric and magnetic radii, as well as, the magnetic moment. We compare our results to experiment as well as to other recent lattice QCD calculations.

Microbial protein synthesis, digestion and lactation responses of cows to grass or grass-red clover silage diet supplemented with barley or oats

Directory of Open Access Journals (Sweden)

A. VANHATALO

2008-12-01

Full Text Available The study was conducted to evaluate effects of silage type (grass-red clover vs. pure grass and grain supplement (oats vs. barley on rumen fermentation, post-ruminal nutrient flows, diet digestion and milk production. Four primiparous Finnish Ayrshire cows fitted with cannulae in the rumen and duodenum were used in a 4 × 4 Latin square experiment with four 28-d experimental periods and 2 × 2 factorial arrangements of treatments. Using red clover-containing (40% silage rather than pure grass silage had minor effects on rumen fermentation or diet digestion but increased non-ammonia nitrogen (N flow in terms of increased flows of microbial and dietary N entering to the small intestine. This was reflected as a reduced ruminal N degradability on grass-red clover diets. Furthermore, grass-red clover diets in comparison to grass silage diets increased milk lactose concentration and yields of milk, protein and lactose. Feeding oats in replacement for barley had minor effects on rumen fermentation or post-ruminal non-ammonia N flows but reduced digestibility of organic matter and neutral detergent fibre in the diet. Using oats rather than barley increased yields of milk and lactose but reduced milk protein concentration. Oats also increased proportions of C18:0 and C18:1 in milk fat and reduced those of C10:0 to C16:0. It is concluded that inclusion of red clover and replacement of barley with oats in grass silage based diets have beneficial effects in dairy cow production.;

Cytoskeleton-amyloplast interactions in sweet clover

Science.gov (United States)

Guikema, J. A.; Hilaire, E.; Odom, W. R.; Spooner, B. S. (Principal Investigator)

1993-01-01

The distribution of organelles within columella cells of sweet clover was examined by transmission electron microscopy following growth under static or clinorotating conditions. A developmentally conditioned polarity was observed, with a proximal location of the nucleus and a distal accumulation of the endoplasmic reticulum. This polarity was insensitive to clinorotation. In contrast, clinorotation altered the location of amyloplasts. Application of cytoskeletal poisons (colchicine, cytochalasin D, taxol, and phalloidin), especially during clinorotation, had interesting effects on the maintenance of columella cell polarity, with a profound effect on the extent, location, and structure of the endoplasmic reticulum. The site of cytoskeletal interactions with sedimenting amyloplasts is thought to be the amyloplast envelope. An envelope fraction, having over 17 polypeptides, was isolated using immobilized antibody technology, and will provide a means of assessing the role of specific peptides in cytoskeleton/amyloplast interactions.

Biochar application rate affects biological nitrogen fixation in red clover conditional on potassium availability

NARCIS (Netherlands)

Mia, S.; van Groeningen, J.W.; Van de Voorde, T.F.J.; Oram, N.J.; Bezemer, T.M.; Mommer, Liesje; Jeffery, S.

2014-01-01

Increased biological nitrogen fixation (BNF) by legumes has been reported following biochar application to soils, but the mechanisms behind this phenomenon remain poorly elucidated. We investigated the effects of different biochar application rates on BNF in red clover (Trifolium pratense L.). Red

Phenotypic and genetic characterization of western prairie clover collections from the western USA

Science.gov (United States)

Kishor Bhattarai; B. Shaun Bushman; Douglas A. Johnson; John G. Carman

2010-01-01

Few North American legumes are available for rangeland revegetation in the semiarid western United States. Western prairie clover (Dalea ornata [Douglas ex Hook.] Eaton & J. Wright) is a perennial legume with desirable forage characteristics and is distributed in the northern Great Basin, Snake River Basin, and southern Columbia Plateau. Understanding the...

Relationships between Nitrate and Oxygen Supply in Symbiotic Nitrogen Fixation by White Clover

DEFF Research Database (Denmark)

Minchin, F. R.; Ines Minguez, M.; Sheedy, J. E.

1986-01-01

Exposure of mature, nodulated plants of white clover (Trifolium repens) cv. Blanca to 330 mg dm−3 NO3-N for 8 d caused nitrogenase activity per plant to decrease by 80%. Total nodulated root respiration was not significantly affected but analysis of its components showed an 81% decrease in nitrog...

Models for coolant void reactivity evaluation in Candu Generation II and III+

International Nuclear Information System (INIS)

Popov, Alexi V.; Chambon, Richard P.; Le Tellier, Romain; Marleau, Guy; Hebert, Alain

2008-01-01

In the simulation of large-break loss-of-coolant accidents, homogenised cross-sections from trans- port calculations are used. These are usually computed in single cells or lattices representative for an infinite repeated pattern. Large coolant accidents in Candu, however, usually exhibit a checkerboard pattern of cooled and voided channels represented by lattices. It is reasonable, therefore, that homogenised cross-sections be produced in assemblies of lattices. This allows simulating the checkerboard voiding pat- tern and more realistically reproducing the lattice boundary conditions. The result is better simulation of the accident and more precise evaluation of coolant-void reactivity. For the present study, homogenised cross-sections are generated in a 2x2 heterogeneous assembly of four lattices for Generation II and III+ Candu designs. Results of reactivity calculations with the reactor code are compared to those using the traditional method. The difference is significant for Generation III+ Candu. (authors)

Early interspecific interference in the wheat/faba bean (Triticum aestivum/ Vicia faba ssp. minor and rapeseed/squarrosum clover (Brassica napus var. oleifera/Trifolium squarrosum intercrops

Directory of Open Access Journals (Sweden)

Paolo Benincasa

2012-04-01

Full Text Available Most of research on intercrops evaluate performances and interference between species on the basis of final yield, while little knowledge is available on the interference in early stages and at the root level, at least for cultivated intercrops. In fact, in the few studies on this subject species are often combined minding at experimental needs (e.g. common substrate, temperature and water requirements, easy root separation more than at their actual use in the farm. The present work evaluates interspecific interference during early developmental stages for two intercrops of agricultural interest: soft wheat-faba bean and rapeseed-squarrosum clover. Improving this knowledge would help intercrop growth modelling and rational cultivation. The experiments were carried out on soft wheat (Triticum aestivum, faba bean (Vicia faba var. minor, rapeseed (Brassica napus var. oleifera and squarrosum clover (Trifolium squarrosum, germinated and grown until 32 days after sowing (DAS as one-species stands or as wheat/faba bean and rapeseed/squarrosum clover intercrops, with different densities and proportions for the two species in each couple. Germination was studied in controlled-temperature chamber, plantlet growth was studied on pots in the greenhouse. During germination no interspecific interference was observed for both wheat/faba bean and rapeseed/squarrosum clover intercrops. During plantlet growth, interspecific interference occurred in both intercrops causing variations in whole plant and root dry matter accumulation. In the wheat/faba bean intercrop each species suffered from the competitive effect of the companion species and faba bean was the dominant species when present in lower proportion than wheat. The unexpectedly high aggressivity of faba bean may be explained either with the greater seed size that could have represented an initial advantage within the short duration of the experiment or with the competition towards wheat for substrate N

Effects of feeding level and NDF content of grass-clover silages on chewing activity, fecal particle size and NDF digestibility in dairy heifers

DEFF Research Database (Denmark)

Schulze, Anne-Katrine Skovsted; Weisbjerg, Martin Riis; Nørgaard, Peder

2014-01-01

intake (PRumination time per kg DM intake (Pcontents (Prumination with greater...... NDF content (Prumination time increased with greater NDF content (Pcontent (P...The objective of this study was to assess effects of feed intake and NDF content of highly digestible grass-clover silage on chewing behavior, fecal particle size distribution and apparent digestibility in restrictively fed heifers. Four grass-clover silages (Lolium perenne, Trifolium pratense...

Medium-term response of microbial community to rhizodeposits of white clover and ryegrass and tracing of active processes induced by 13C and 15N labelled exudates

DEFF Research Database (Denmark)

Kusliene, Gedrime; Rasmussen, Jim; Kuzyakov, Yakov

2014-01-01

and actinomycetes was unaffected by plant species, but pool of Gram-negative and Gram-positive bacteria was greater under white clover at the 10 percent significance level. In the short term, microorganisms more actively utilised fresh exudates (13C-labelled) of ryegrass than of white clover. We expected ryegrass...... microbial groups in soil under white clover (Trifolium repens L.) and ryegrass (Lolium perenne L.) following leaf-labelling with 13C-bicarbonate and 15N-urea. In this way microbial N and 15N and the composition of PLFAs reflect the medium-term (two months) response of microorganisms to rhizodeposits......, whereas the 13C-label of the PLFAs reflects the short-term (one week) utilisation of root exudates following labelling of shoots. In the medium term, microbial biomass N and 15N were greater under the ryegrass, whereas total PLFA was higher under white clover. The relative abundance of fungi...

Estimating legume N-2 fixation in grass-clover mixtures of a grazed organic cropping system using two N-15 methods

DEFF Research Database (Denmark)

Vinther, F.P.; Jensen, E.S.

2000-01-01

The input of Nitrogen (N) through symbiotic N-2 fixation (SNF) in grass-clover mixtures was determined in an organic cropping. system for grazing during 3 years. The mixture of perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) was established by undersowing in spring...... barley (Hordeum vulgare L.) and maintained subsequently for two production years. Dinitrogen fixation was determined using the N-15 isotope dilution techniques and two labelling procedures. Using either pre-labelling of the soil with immobilisation of the N-15 by addition of a carbon source before...

FLIC-overlap fermions and topology

International Nuclear Information System (INIS)

Kamleh, W.; Kusterer, D.J.; Leinweber, D.B.; Williams, A.G.

2003-01-01

APE smearing the links in the irrelevant operators of clover fermions (Fat-Link Irrelevant Clover (FLIC) fermions) provides significant improvement in the condition number of the Hermitian-Dirac operator and gives rise to a factor of two savings in computing the overlap operator. This report investigates the effects of using a highly-improved definition of the lattice field-strength tensor F μν in the fermion action, made possible through the use of APE-smeared fat links in the construction of the irrelevant operators. Spurious double-zero crossings in the spectral flow of the Hermitian-Wilson Dirac operator associated with lattice artifacts at the scale of the lattice spacing are removed with FLIC fermions composed with an O(α 4 )-improved lattice field strength tensor. Hence, FLIC-Overlap fermions provide an additional benefit to the overlap formalism: a correct realization of topology in the fermion sector on the lattice

Determination of toxicity limiting values of Zn, Cu, and Pb for oat and red clover

Energy Technology Data Exchange (ETDEWEB)

Hodenberg, A V; Finck, A

1975-01-01

Toxicity limiting values of Zn, Cu and Pb are determined in order to investigate the causes of growth damages in certain fields. Since the true toxicity limit is difficult to estimate, a somewhat higher content is called the toxicity limiting value resulting after the subtraction of a significant yield difference. The pot experiments with increasing fertilization of Zn, Cu and Pb in soil cultures gave the following results. For Zn, the toxicity limit is 410 ppm in oats at the beginning of tilling. In red clover six weeks of age, it is only 290 ppm of Zn and therefore much lower. For Cu, the toxicity limit is 20 ppm in oats at the beginning of tilling and 18 ppm in six weeks old red clover. For Pb, a toxic effect could be observed above 50 ppm, but this does not seem to be the true limit because of disturbing salt effects.

Sexual polyploidization in red clover Poliploidização sexual em trevo vermelho

Directory of Open Access Journals (Sweden)

Carine Simioni

2006-02-01

Full Text Available Because sexual polyploidization broadens genetic basis and supply plant breeders with more variability for the selection process, it can be useful in red clover breeding. This paper reports results of three crossing cycles, starting from a parental generation of tetraploid red clover plants (female parent, and diploids from the Quiñiqueli cultivar, selected for production of more than 1% of giant pollen grains (male parent aiming to obtain tetraploid plants to be used in red clover breeding programs. Crosses in the next generations were performed by mutual cross-pollinations. Chromosome number chimerism and high pollen sterility were detected in F1, F2 and F3, but there was a trend towards increasing seed production and seed viability along the generations, probably due to successful competition between fertile and sterile gametes. The identification of fertile triploids, as well as their recurrent formation along the generations, indicates that triploid block is not complete in red clover, and that triploids may be successfully used as a bridge for the production of sexual polyploids.Porque a poliploidização sexual amplia a base genética e proporciona aos melhoristas maior variabilidade para o processo de seleção, ela pode ser uma ferramenta útil ao melhoramento de trevo vermelho. Com o objetivo de obter plantas tetraplóides que possam ser utilizadas em programas de melhoramento de trevo vermelho, este trabalho relata resultados de três ciclos de cruzamentos, partindo de uma população parental de plantas tetraplóides de trevo vermelho, como genitores femininos, e de diplóides da cultivar Quiñiqueli, selecionados para produção de mais de 1% de grãos de pólen gigantes, como genitores masculinos. Nas outras gerações, os cruzamentos foram realizados por polinizações cruzadas mútuas. Quimerismo para número cromossômico e alta esterilidade de pólen foram detectados em F1 , F2 e F3, mas houve uma tendência para aumento da

Biological activity of clovers - free radical scavenging ability and antioxidant action of six Trifolium species.

Science.gov (United States)

Kolodziejczyk-Czepas, Joanna; Nowak, Pawel; Kowalska, Iwona; Stochmal, Anna

2014-10-01

Clovers were chosen on the basis of traditional medicine recommendations, agricultural value, or available information on their promising chemical profiles. This study evaluates and compares free radical scavenging and antioxidant properties of six clover species: Trifolium alexandrinum L. (Leguminosae), Trifolium fragiferum L., Trifolium hybridum L., Trifolium incarnatum L., Trifolium resupinatum var. majus Boiss., and Trifolium resupinatum var. resupinatum L. Free radical scavenging activity of the extracts (1.5-50 µg/ml) was estimated by reduction of 1,1-diphenyl-2-picrylhydrazyl (DPPH(•)) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic) acid (ABTS(•)) radicals. The Trifolium extract effects on total antioxidant capacity of blood plasma were determined by the reduction of ABTS(•+) and DPPH(•) radicals, as well as with the use of the ferric reducing ability of plasma (FRAP) assay. The UPLC analysis of chemical profiles of the examined extracts showed the presence of three or four groups of phenolic substances, including phenolic acids, clovamides, isoflavones, and other flavonoids. The measurements of free radical scavenging and ferric reducing ability of the examined clover extracts revealed the strongest effect for T. alexandrinum. Furthermore, antioxidant activity assays in human plasma have shown protective effects of all extracts against peroxynitrite-induced reduction of total antioxidant capacity. Trifolium plants may be a rich source of bioactive substances with antioxidant properties. The examined extracts displayed free radical scavenging action and partly protected blood plasma against peroxynitrite-induced oxidative stress; however, the beneficial effects of T. alexandrinum and T. incarnatum seem to be slightly higher.

Effect of aditive supplementation to ensiled red clover on voluntary intake, digestibility and N balance

Directory of Open Access Journals (Sweden)

Marina Vranić

2009-06-01

Full Text Available The objective of this study was to determine effect of additive supplementation to red clover silage on ad libitum intake of fresh silage and dry matter (DM, in vivo digestibility of DM, organic matter (OM, OM in DM (D-value, crude protein (CP and nitrogen (N balance. Red clover was harvested at 60% bloom stage. It was ensiled into round bales without an additive (CD and with an additive supplementation (CDA in the amount of 2 L t-1 fresh material. Statistically lower (P<0.001 DM content was recorded in CD (405 g kg-1 fresh sample in comparison with CDA (665 g ST kg-1 fresh sample. Statistically higher CP content (P<0.001 was recorded in CD (127 g kg-1 ST in comparison with CDA (110 g SP kg-1 ST. CD had lower pH (P<0.001 (4.9 in comparison with CDA (5.2. No differences were recorded in NH3 between treatments. Ad libitum intake of fresh silage and silage DM was higher (P<0.001 and P<0.01, respectively in CD in comparison with CDA. Digestibility of DM, OM, CP, D-value and N balance were not different between treatments. It was concluded that the positive effect of additive supplementation to red clover silage on chemical composition, ad libitum intake, digestibility and N balance was not recorded due to applied ensiling technology as additive can improve feeding value of roughage, but it is not a replacement for good management practices.

The beneficial effect of dual inoculation of vesicular-arbuscular mycorrhizae + rhizobium on growth of white clover

Directory of Open Access Journals (Sweden)

Lin, XG.

1993-01-01

Full Text Available Investigation on the effect of phosphorus on vesicular-arbuscular mycorrhizal infection, and dual inoculation of vesicular-arbuscular mycorrhizae + rhizobium on growth of white clover under field microplots and pot experiments was conducted on fluvo-aquic soils of semi-arid region in north China. The results showed that 60 kg P205 ha in form of superphosphate was the most favorable phosphorus level for vesicular-arbuscular mycorrhizal infection ; mycorrhizal infection, nodulation, dry weight of shoots and roots, total uptake of nitrogen, phosphorus and other elements, the final yields and recovery of phosphorus of white clover were significantly increased by vesicular-arbuscular mycorrhizal inoculation and dual inoculation with vesicular-arbuscular mycorrhizal fungi and rhizobium. The highest response of inoculation was obtained by adding fertilizer phosphorus at the level of 60 kg P205 ha in form of superphosphate.

A cluster-bethe-lattice approach to spin-waves in dilute ferromagnets

International Nuclear Information System (INIS)

Salzberg, J.B.; Silva, C.E.T.G. da; Falicov, L.M.

1975-01-01

The spin-wave spectra of a dilute ferromagnet within the cluster-bethe-lattice approximation is studied. Short range order effects for the alloy are included. A study of finite size clusters connected at their edges to Bethe lattices of the same coordination number allows one to determine:(i) the stability condition for the magnetic system; (ii) the continuum spin-wave local density of states and (iii) the existence of localized states below and above the continuum states

Effect of Pseudomonas fluorescens and pyoverdine on the phytoextraction of cesium by red clover in soil pots and hydroponics.

Science.gov (United States)

Hazotte, Alice; Péron, Olivier; Gaudin, Pierre; Abdelouas, Abdesselam; Lebeau, Thierry

2018-05-12

With the aim of improving the phytoextraction rate of cesium (Cs), the effect of Pseudomonas fluorescens ATCC 17400 and its siderophore pyoverdine (PVD) on the uptake of Cs by red clover was studied in soil pots. This work also provides a mechanistic understanding of the Cs-bacteria (or PVD)-illite-plant interactions by using a simplified experimental design, i.e., hydroponics with either Cs in solution or Cs-spiked illite in suspension. For soil spiked with 11.2 mmol kg -1 (1480 mg kg -1 ) of Cs, 0.43% of total Cs was taken up by red clover in 12 days (119 μmol g -1 (16 mg g -1 ) of Cs dry matter in roots and 40 μmol g -1 (5 mg g -1 ) in shoots). In hydroponics with Cs in solution (0.1 mmol L -1 or 13 mg L -1 ), 75% of Cs was taken up vs. only 0.86% with Cs-spiked illite suspension. P. fluorescens and PVD did not increase Cs concentrations in aboveground parts and roots of red clover and even decreased them. The damaging effect of PVD on red clover growth was demonstrated with the biomass yielding 66% of the control in soil pots (and 100% mortality after 12 days of exposition) and only 56% in hydroponics (78% with illite in suspension). Nonetheless, PVD and, to a lesser extent, P. fluorescens increased the translocation factor up to a factor of 2.8. This study clearly showed a direct damaging effect of PVD and to a lower extent the retention of Cs by biofilm covering both the roots and illite, both resulting in the lower phytoextraction efficiency.

Performance comparison for modes of operation and suppression cases of the clover detector

International Nuclear Information System (INIS)

Kshetri, R

2014-01-01

Peak-to-total ratios have been extracted for a segmented clover detector for various modes of operation and suppression cases. Based on absorption and scattering of gamma-rays, a formalism has been presented for quantifying the advantages of using addback mode and active suppression. Further investigations have been performed to find if the reduction of background counts is caused more by active suppression or by addback process

Towards an optimal sampling strategy for assessing genetic variation within and among white clover (Trifolium repens L. cultivars using AFLP

Directory of Open Access Journals (Sweden)

Khosro Mehdi Khanlou

2011-01-01

Full Text Available Cost reduction in plant breeding and conservation programs depends largely on correctly defining the minimal sample size required for the trustworthy assessment of intra- and inter-cultivar genetic variation. White clover, an important pasture legume, was chosen for studying this aspect. In clonal plants, such as the aforementioned, an appropriate sampling scheme eliminates the redundant analysis of identical genotypes. The aim was to define an optimal sampling strategy, i.e., the minimum sample size and appropriate sampling scheme for white clover cultivars, by using AFLP data (283 loci from three popular types. A grid-based sampling scheme, with an interplant distance of at least 40 cm, was sufficient to avoid any excess in replicates. Simulations revealed that the number of samples substantially influenced genetic diversity parameters. When using less than 15 per cultivar, the expected heterozygosity (He and Shannon diversity index (I were greatly underestimated, whereas with 20, more than 95% of total intra-cultivar genetic variation was covered. Based on AMOVA, a 20-cultivar sample was apparently sufficient to accurately quantify individual genetic structuring. The recommended sampling strategy facilitates the efficient characterization of diversity in white clover, for both conservation and exploitation.

Nucleon form factors and structure functions from Nf=2 Clover fermions

International Nuclear Information System (INIS)

Collins, S.; Goeckeler, M.; Haegler, P.

2010-12-01

We give an update on our ongoing efforts to compute the nucleon's form factors and moments of structure functions using N f =2 flavours of non-perturbatively improved Clover fermions. We focus on new results obtained on gauge configurations where the pseudo-scalar meson mass is in the range of 170-270 MeV. We compare our results with various estimates obtained from chiral effective theories since we have some overlap with the quark mass region where results from such theories are believed to be applicable. (orig.)

Arbuscular mycorrhiza enhanced arsenic resistance of both white clover (Trifolium repens Linn.) and ryegrass (Lolium perenne L.) plants in an arsenic-contaminated soil

Energy Technology Data Exchange (ETDEWEB)

Dong Yan; Zhu Yongguan [Department of Soil Environmental Science, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China); Smith, F. Andrew [Soil and Land Systems, School of Earth and Environmental Sciences, Waite Campus, University of Adelaide, Adelaide, SA 5005 (Australia); Wang Youshan [Institute of Plant Nutrition and Resources, Beijing Academy of Agriculture and Forestry, Beijing 100089 (China); Chen Baodong [Department of Soil Environmental Science, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China)], E-mail: bdchen@rcees.ac.cn

2008-09-15

In a compartmented cultivation system, white clover (Trifolium repens Linn.) and ryegrass (Lolium perenne L.), with their roots freely intermingled, or separated by 37 {mu}m nylon mesh or plastic board, were grown together in an arsenic (As) contaminated soil. The influence of AM inoculation on plant growth, As uptake, phosphorus (P) nutrition, and plant competitions were investigated. Results showed that both plant species highly depended on mycorrhizas for surviving the As contamination. Mycorrhizal inoculation substantially improved plant P nutrition, and in contrast markedly decreased root to shoot As translocation and shoot As concentrations. It also showed that mycorrhizas affected the competition between the two co-existing plant species, preferentially benefiting the clover plants in term of nutrient acquisition and biomass production. Based on the present study, the role of AM fungi in plant adaptation to As contamination, and their potential use for ecological restoration of As contaminated soils are discussed. - Both white clover and ryegrass highly depend on the mycorrhizal associations for surviving heavy arsenic contamination.

Arbuscular mycorrhiza enhanced arsenic resistance of both white clover (Trifolium repens Linn.) and ryegrass (Lolium perenne L.) plants in an arsenic-contaminated soil

International Nuclear Information System (INIS)

Dong Yan; Zhu Yongguan; Smith, F. Andrew; Wang Youshan; Chen Baodong

2008-01-01

In a compartmented cultivation system, white clover (Trifolium repens Linn.) and ryegrass (Lolium perenne L.), with their roots freely intermingled, or separated by 37 μm nylon mesh or plastic board, were grown together in an arsenic (As) contaminated soil. The influence of AM inoculation on plant growth, As uptake, phosphorus (P) nutrition, and plant competitions were investigated. Results showed that both plant species highly depended on mycorrhizas for surviving the As contamination. Mycorrhizal inoculation substantially improved plant P nutrition, and in contrast markedly decreased root to shoot As translocation and shoot As concentrations. It also showed that mycorrhizas affected the competition between the two co-existing plant species, preferentially benefiting the clover plants in term of nutrient acquisition and biomass production. Based on the present study, the role of AM fungi in plant adaptation to As contamination, and their potential use for ecological restoration of As contaminated soils are discussed. - Both white clover and ryegrass highly depend on the mycorrhizal associations for surviving heavy arsenic contamination

Environmental life cycle assessments of producing maize, grass-clover, ryegrass and winter wheat straw for biorefinery

DEFF Research Database (Denmark)

Parajuli, Ranjan; Kristensen, Ib Sillebak; Knudsen, Marie Trydeman

2017-01-01

The aim of this study is to assess the potential environmental impacts of producing maize, grass-clover, ryegrass, and straw from winter wheat as biomass feedstocks for biorefinery. The Life Cycle Assessment (LCA) method included the following impact categories: Global Warming Potential (GWP100),...

Optimization of a protocol for direct organogenesis of red clover (Trifolium pratense L. meristems for breeding purposes

Directory of Open Access Journals (Sweden)

JUAN C CARRILLO

2004-01-01

Full Text Available A series of experiments were carried out in order to optimize a protocol for the direct organogenesis of Chilean red clover germplasm. A range of cultivars were used to analyze the effect of explant source (crown or stem meristems of vegetative plants, culture media and plant growth regulators. Our findings showed that stem meristems were easier to obtain, presented lower levels of contamination and a better development than crown meristems. The L2 medium showed better results than B5 and MS media for the cultivars and experimental lines studied. L2 medium supplemented with 0.003 mg/l of 4-amino-3,5,6-trichloropicolinic acid and 1.0 mg/l of 6-benzylaminopurine gave consistently better results and will be applied in our breeding program to propagate, maintain and eliminate viruses from elite red clover clones.

Cleaning the Soil from Zinc Using Red Clovers “Arimaičiai”

OpenAIRE

Audronė Mikalajūnė; Giedrė Jasulaitytė

2011-01-01

Zinc as a nutrition element is required to plants in small quantities to maintain normal functions of metabolism mechanisms. Our work analyses the efficiency of red clovers “Arimaičiai” for cleaning zinc from the soil contaminated with zinc under laboratory conditions. Seeds were sown in three differently polluted soils: clean soil, once contaminated with zinc and periodically contaminated with zinc soil. Zinc concentration in one time contaminated soil was 45 mg/kg. After 6 months of phytore...

Biologically fixed N2 as a source for N2O production in a grass–clover mixture, measured by 15N2 (erratum i vol. 74 p. 203)

DEFF Research Database (Denmark)

Carter, Mette Sustmann; Ambus, P.

2006-01-01

The contribution of biologically fixed dinitrogen (N-2) to the nitrous oxide (N2O) production in grasslands is unknown. To assess the contribution of recently fixed N-2 as a source of N2O and the transfer of fixed N from clover to companion grass, mixtures of white clover and perennial ryegrass...

Symmetry of semi-reduced lattices.

Science.gov (United States)

Stróż, Kazimierz

2015-05-01

The main result of this work is extension of the famous characterization of Bravais lattices according to their metrical, algebraic and geometric properties onto a wide class of primitive lattices (including Buerger-reduced, nearly Buerger-reduced and a substantial part of Delaunay-reduced) related to low-restricted semi-reduced descriptions (s.r.d.'s). While the `geometric' operations in Bravais lattices map the basis vectors into themselves, the `arithmetic' operators in s.r.d. transform the basis vectors into cell vectors (basis vectors, face or space diagonals) and are represented by matrices from the set {\\bb V} of all 960 matrices with the determinant ±1 and elements {0, ±1} of the matrix powers. A lattice is in s.r.d. if the moduli of off-diagonal elements in both the metric tensors M and M(-1) are smaller than corresponding diagonal elements sharing the same column or row. Such lattices are split into 379 s.r.d. types relative to the arithmetic holohedries. Metrical criteria for each type do not need to be explicitly given but may be modelled as linear derivatives {\\bb M}(p,q,r), where {\\bb M} denotes the set of 39 highest-symmetry metric tensors, and p,q,r describe changes of appropriate interplanar distances. A sole filtering of {\\bb V} according to an experimental s.r.d. metric and subsequent geometric interpretation of the filtered matrices lead to mathematically stable and rich information on the Bravais-lattice symmetry and deviations from the exact symmetry. The emphasis on the crystallographic features of lattices was obtained by shifting the focus (i) from analysis of a lattice metric to analysis of symmetry matrices [Himes & Mighell (1987). Acta Cryst. A43, 375-384], (ii) from the isometric approach and invariant subspaces to the orthogonality concept {some ideas in Le Page [J. Appl. Cryst. (1982), 15, 255-259]} and splitting indices [Stróż (2011). Acta Cryst. A67, 421-429] and (iii) from fixed cell transformations to transformations

Assessment of Protective Effect of Some Modern Agrochemicals against Ozone-Induced Stress in Sensitive Clover and Tobacco Cultivars.

Science.gov (United States)

Blum, Oleg; Didyk, Nataliya; Pavluchenko, Nataliya; Godzik, Barbara

2011-01-01

Some modern agrochemicals with antioxidant potential were tested for their protective effect against ozone injury using clover and tobacco ozone-sensitive cultivars as model plants subjected to ambient ozone at two sites (Kyiv city in Ukraine and Szarów village in Poland). All used agrochemicals showed partial protective effects against ozone injury on clover and tobacco. Conducted studies confirmed the effectiveness of modern fungicides belonging to strobilurin group as protectants of sensitive crops against ozone damage. The effectiveness of new growth regulators "Emistym C" and "Agrostymulin" was showed for the first time. Out of the studied agrochemicals, fungicide "Strobi" and natural growth regulator "Emistym C" demonstrated the best protective effects. These agrochemicals present promise for further studies of their possible utilization for enhancement of ozone tolerance of sensitive crops.

Effects of soil properties and P fertilizers on trace element uptake of red clover in a pot experiment

International Nuclear Information System (INIS)

Osztoics, E.; Bujtas, K.

1999-01-01

The impacts of superphosphate and Algerian phosphate rock and their various application rates on soil pH and on the availability of trace elements by red clover were studied in a pot experiment on several types of acidic soils from the Carpathian basin. The differences among the soils' original pH and texture, and those differences in soil pH, which resulted from the application of different P forms and rotes were reflected in the Mn, Ni, Al, Co, Sr, Cd and Cr contents of red clover. Plant concentrations of those elements were smaller on the slightly acidic than on the strongly and extremely strongly acidic soils. Elemental concentrations were generally higher when there was less time between two cuts, and decreased in the later cuts. Refs. 11 (author)

Meat goat kids finished on alfalfa, red clover, or orchardgrass pastures: Carcass merit and meat quality

Science.gov (United States)

This experiment was conducted in 2005-2007 to evaluate carcass and meat quality parameters when meat goat kids were finished on alfalfa (Medicago sativa L; ALF); red clover (Trifolium pretense L.; RCG); or orchardgrass (Dactylis glomerata L; OGR) pastures. Final shrunk body weights were similar whe...

Does introduction of clover in an agricultural grassland affect the food base and functional diversity of Collembola?

NARCIS (Netherlands)

Annibale, D' Alessandra; Sechi, Valentina; Larsen, Thomas; Christensen, Søren; Krogh, Paul Henning; Eriksen, Jørgen

2017-01-01

Introduction of legumes (i.e. white clover) in agricultural grasslands is a common practice to improve yields, but how this affects soil fauna populations, particularly mesofauna, is still poorly understood. We investigated taxonomical and functional differences of Collembola communities between

Isolation of Burkholderia cepacia JB12 from lead- and cadmium-contaminated soil and its potential in promoting phytoremediation with tall fescue and red clover.

Science.gov (United States)

Jin, Zhong Min; Sha, Wei; Zhang, Yan Fu; Zhao, Jing; Ji, Hongyang

2013-07-01

Phytoremediation combined with suitable microorganisms and biodegradable chelating agents can be a means of reclaiming lands contaminated by toxic heavy metals. We investigated the ability of a lead- and cadmium-resistant bacterial strain (JB12) and the biodegradable chelator ethylenediamine-N,N'-disuccinic acid (EDDS) to improve absorption of these metals from soil by tall fescue and red clover. Strain JB12 was isolated from contaminated soil samples, analysed for lead and cadmium resistance, and identified as Burkholderia cepacia. Tall fescue and red clover were grown in pots to which we added JB12, (S,S)-EDDS, combined JB12 and EDDS, or water only. Compared with untreated plants, the biomass of plants treated with JB12 was significantly increased. Concentrations of lead and cadmium in JB12-treated plants increased significantly, with few exceptions. Plants treated with EDDS responded variably, but in those treated with combined EDDS and JB12, heavy metal concentrations increased significantly in tall fescue and in the aboveground parts of red clover. We conclude that JB12 is resistant to lead and cadmium. Its application to the soil improved the net uptake of these heavy metals by experimental plants. The potential for viable phytoremediation of lead- and cadmium-polluted soils with tall fescue and red clover combined with JB12 was further enhanced by the addition of EDDS.

Morphological traits and yield of red clover (Trifolium pratense L. genotypes with varying inflorescence length

Directory of Open Access Journals (Sweden)

Tadeusz Zając

2013-12-01

Full Text Available Two red clover breeding strains with elongated flower heads, developed by one of the authors (H.Góral, were studied for forage and seed yield and compared to the standard cultivar 'Nike'. In addition, six morphological shoot traits were measured and their interrelations were computed. The leaf area index (LAI of successive cuts in two harvest years was determined on the basis of shoot density and leaf area of individual shoots. All three genotypes exhibited a high leaf area on shoots and a very high forage productivity. Among the morphological traits only shoot height could be a good selective criterion because it is easily measured, is significantly associated with shoot weight and shoot leaf area and its variation is low. Both strains, particularly the one with longer inflorescences belong to short-lived red clover forms giving satis factory forage and seed yields in the first harvest year. Depending on the strain the number of seeds per elongated inflorescence in the first harvest year was higher by 92 and 42% compared to that of a standard cultivar.

Evaluation of physical structure value in spring-harvested grass/clover silage and hay fed to heifers

DEFF Research Database (Denmark)

Schulze, A.K.S.; Nørgaard, P.; Byskov, M.V.

2015-01-01

The physical structure value of conserved grass/clover forages of spring harvest was evaluated by assessing effects of harvest time, conservation method, iNDF/NDF ratio and NDF intake (NDFI) per kg BW on chewing activity and fecal particle size in dairy heifers. A mixed sward consisting of ryegrass...

Dinitrogen fixation in white clover grown in pure stand and mixture with ryegrass estimated by the immobilized 15N isotope dilution method

DEFF Research Database (Denmark)

Jørgensen, F.V.; Jensen, E.S.; Schjørring, J.K.

1999-01-01

Dinitrogen fixation in white clover (Trifolium repens L.) grown in pure stand and mixture with perennial ryegrass (Lolium perenne L.) was determined in the field using N-15 isotope dilution and harvest of the shoots. The apparent transfer of clover N to perennial ryegrass was simultaneously...... assessed. The soil was labelled either by immobilizing N-15 in organic matter prior to establishment of the sward or by using the conventional labelling procedure in which N-15 fertilizer is added after sward establishment. Immobilization of N-15 in the soil organic matter has not previously been used...

Metabolisable protein supply to lactating dairy cows increased with increasing dry matter concentration in grass-clover silage

DEFF Research Database (Denmark)

Johansen, Marianne; Hellwing, Anne Louise Frydendahl; Lund, Peter

2017-01-01

The aim of this experiment was to study the effect of increased dry matter (DM) concentration in grass-clover silage, obtained by extending the pre-wilting period before ensiling, on the amount of metabolisable protein (MP) supplied to lactating dairy cows. Spring growth and first regrowth of grass...... and faeces, respectively, were collected over 94 h to cover the diurnal variation, pooled, and subsequently analysed. Rumen fluid was collected in same sampling procedure. To estimate the duodenal flow of microbial protein, microbes were isolated from the rumen and analysed for amino acids (AA) and purines...... flow of AA. The higher duodenal flow of AA derived from a lower rumen degradation of feed protein and a tendency towards a higher microbial synthesis in the rumen. Fibre digestibility and CH4 production were not affected by silage DM concentration. In conclusion, MP concentration in grass-clover silage...

Lattice strain accompanying the colossal magnetoresistance effect in EuB6.

Science.gov (United States)

Manna, Rudra Sekhar; Das, Pintu; de Souza, Mariano; Schnelle, Frank; Lang, Michael; Müller, Jens; von Molnár, Stephan; Fisk, Zachary

2014-08-08

The coupling of magnetic and electronic degrees of freedom to the crystal lattice in the ferromagnetic semimetal EuB(6), which exhibits a complex ferromagnetic order and a colossal magnetoresistance effect, is studied by high-resolution thermal expansion and magnetostriction experiments. EuB(6) may be viewed as a model system, where pure magnetism-tuned transport and the response of the crystal lattice can be studied in a comparatively simple environment, i.e., not influenced by strong crystal-electric field effects and Jahn-Teller distortions. We find a very large lattice response, quantified by (i) the magnetic Grüneisen parameter, (ii) the spontaneous strain when entering the ferromagnetic region, and (iii) the magnetostriction in the paramagnetic temperature regime. Our analysis reveals that a significant part of the lattice effects originates in the magnetically driven delocalization of charge carriers, consistent with the scenario of percolating magnetic polarons. A strong effect of the formation and dynamics of local magnetic clusters on the lattice parameters is suggested to be a general feature of colossal magnetoresistance materials.

Effect of Mycorrhizal Fungi and Trifluralin Herbicide on Emergence, Growth and Root Colonization of Clover (Trifolium repens L.

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Hassan Shahgholi

2016-09-01

Full Text Available Introduction: Herbicides, despite of their control of weeds, have the potential to affect sensitive crops in rotation and also beneficial non-targeted soil microbes including vesicular arbuscular mycorrhiza (VAM fungi (6. AM fungi can increase the growth of crops through increasing uptake of phosphorus and insoluble micronutrients, and indirectly by improving soil quality parameters (30. However, several authors have reported different effects of herbicides on VAM symbiosis, which ranges from no adverse effects to slightly or highly toxic effects (6. Pesticides have also been reported to stimulate colonization of plant roots by AM fungi (27. Therefore, the objective of this study was to investigate the interaction effects of mycorrhizal fungi and Trifluralin herbicide on the growth and root colonization of clover. Materials and Methods: A factorial experiment was arranged in randomized complete block design with three replicates at the College of Agricultural, University of Shahrood during 2012. Treatments were included three levels of mycorrhiza inoculation, M1: non mycorrhiza (control, M2: Glommus mosseae and M3: Glommus intraradices and herbicide treatments were included four levels of Trifluralin(T1: 0, T2: 1000, T3: 1500 and T4: 2000 ml ha-1. In mycorrhizal treatments, 20 g inoculums were thoroughly mixed with soil. Seeds of clover (Trifolium repens L. were sown in the pots maintained near the field in order to provide normal environmental conditions. Seedlings were thinned to two plants per pot at three leaf stages. At the time of harvesting, the emergence and growth characteristics of clover and root colonization was also registered. Statistical analyses of data were performed with statistical software MSTATC. Significant differences between means refer to the probability level of 0.05 calculated by LSD test. Results and Discussion: The results showed that emergence, uniformity (EU values decreased and time to 10% (D10 and 90% (D90 of

Changes in the spore numbers of AM fungi and in AM colonisation of roots of clovers and grasses on a peat-muck soil with respect to mineral fertilization

International Nuclear Information System (INIS)

Kowalska, T. K.; Kwiatkowaska, E.

2016-01-01

A 4-year plot experiment was conducted to determine the dynamics of changes in the spore density of arbuscular mycorrhizal fungi (AMF) and of the degree of endomycorrhizal colonisation of roots of clovers and meadow grasses on an organic peat-muck soil in a post-marshy habitat, taking into account the effect of mineral fertilisation (NPK). The experimental object comprised four plots that represented the fertilisation treatments, sown with white clover (Trifolium repens L.), red clover (Trifolium pratense L.), smooth meadow-grass (Poa pratensis L.), and a mix of grasses composed of perennial ryegrass (Lolium perenne L.), meadow fescue (Festuca pratensis Huds.), smooth meadow-grass (Poa pratensis L.), and cocksfoot (Dactylis glomerata L.). Analogous sowing was performed on control (non-fertilised) plots. It was found that spores of AMF occurred in 100 percent of the samples of the soil studied, and the average total number of AMF spores isolated from soil under the particular plant combinations was high and amounted to 1858 spores (range from 1392 to 2443) in 100 g of air-dried soil. The percentage share of the clover and grass roots colonised by indigenous endomycorrhizal fungi was very low and varied from 0 to 46 (average from 4.1 percent to 12.2 percent). No correlation was found between the spore numbers of AMF in the soil and the degree of mycorrhized roots of the clovers and grasses. Mineral fertilisation stimulated the sporulation of AM fungi but had no effect on root colonisation by these fungi. (author)

Short-term residual N unaffected by forbs in grass-clover mixtures

DEFF Research Database (Denmark)

Dhamala, Nawa Raj; Rasmussen, Jim; Cong, Wenfeng

2017-01-01

We determined the effect on residual nitrogen (N) of including forbs (chicory, ribwort plantain and caraway) in perennial ryegrass-red clover mixtures. Although soil N inputs during the grassland phase differed markedly between mixtures, in a pot experiment we found no differences...... in the potentially mineralizable N of the soil or in the dry matter production and N content of the spring barley test crop. The fertilizer value of the grassland mixtures corresponded to 10 g N/m2, irrespective of forb inclusion. Thus, the inclusion of nonlegume forbs did not negatively affect short-term residual N...

On Traveling Waves in Lattices: The Case of Riccati Lattices

Science.gov (United States)

Dimitrova, Zlatinka

2012-09-01

The method of simplest equation is applied for analysis of a class of lattices described by differential-difference equations that admit traveling-wave solutions constructed on the basis of the solution of the Riccati equation. We denote such lattices as Riccati lattices. We search for Riccati lattices within two classes of lattices: generalized Lotka-Volterra lattices and generalized Holling lattices. We show that from the class of generalized Lotka-Volterra lattices only the Wadati lattice belongs to the class of Riccati lattices. Opposite to this many lattices from the Holling class are Riccati lattices. We construct exact traveling wave solutions on the basis of the solution of Riccati equation for three members of the class of generalized Holling lattices.

LATTICE: an interactive lattice computer code

International Nuclear Information System (INIS)

Staples, J.

1976-10-01

LATTICE is a computer code which enables an interactive user to calculate the functions of a synchrotron lattice. This program satisfies the requirements at LBL for a simple interactive lattice program by borrowing ideas from both TRANSPORT and SYNCH. A fitting routine is included

Nitrate leaching in maize after cultivation of differently managed grass-clover leys on coarse sand in Denmark

DEFF Research Database (Denmark)

Hansen, Elly Møller; Eriksen, Jørgen

2016-01-01

When grass-clover leys have been ploughed nitrate leaching may increase. However, management of leys before or after ploughing may affect the leaching risk. We examined the effect of cultivating a six year ley, which the last two years had been treated differently (grazing only; spring cut follow...

Effect of maturity and conservation of grass/clover on digestibility and rumen pH in heifers

DEFF Research Database (Denmark)

Koch, A.S.; Nørgaard, P.; Weisbjerg, Martin Riis

2013-01-01

The study aimed to evaluate effects of maturity and conservation of primary growth grass/clover on apparent digestibility and rumen pH. Two batches of mixed ryegrass, red and white clover harvested in 2009 on May 9 and 25 were conserved as either silage or hay. The forages early silage (ES) and hay...... (EH), and late silage (LS) and hay (LH) had DM contents of 45, 84, 25 and 83%, and NDF contents of 32, 44, 42 and 50% of DM, respectively. Forages were fed as sole feed to four Jersey heifers of 435±30 kg BW in a 4×4 Latin square experiment. Feeding level was 90% of individual ad libitum intake......, divided in two daily meals at 0800 and 1530 h. Potentially digestible NDF (DNDF) was determined after 288 h in situ. Apparent digestibility of OM and NDF was estimated using Cr3O2 as marker. Rumen fluid pH in the medial and ventral rumen was measured with 1 h intervals from 0730 to 1530 h. Data...

Bicarbonate as tracer for plant assimilated C and homogeneity of 14C and 15N distribution in ryegrass and white clover tissue by alternative labeling approaches

DEFF Research Database (Denmark)

Rasmussen, Jim; Kusliene, Gedrime; Jacobsen, Ole Stig

2013-01-01

that 15N also had a heterogeneous distribution (up to two orders of magnitude). Conclusion Bicarbonate can efficiently be used to introduce 14C or 13C into plant via the leaf-labeling method. Both 14C and 15N showed heterogeneous distribution in the plant, although the distribution of 15N was more even......Aims: Application of carbon (C) and nitrogen (N) isotopes is an essential tool to study C and N flows in plant-soil-microorganisms systems. When targeting single plants in a community the tracers need to be added via e.g., leaf-labeling or stem-feeding approaches. In this study we: (i) investigated...... if bicarbonate can be used to introduce 14C (or 13C) into white clover and ryegrass, and (ii) compared the patterns of 14C and 15N allocation in white clover and ryegrass to evaluate the homogeneity of tracer distribution after two alternative labeling approaches. Methods Perennial ryegrass and white clover were...

Effect of harvest time of red and white clover silage on chewing activity and particle size distribution in boli, rumen content and faeces in cows.

Science.gov (United States)

Kornfelt, L F; Nørgaard, P; Weisbjerg, M R

2013-06-01

The study examined the effects of harvest time of red and white clover silage on eating and ruminating activity and particle size distribution in feed boli, rumen content and faeces in cows. The clover crops were harvested at two stages of growth and ensiled in bales. Red clover crops had 36% and 45% NDF in dry matter (DM) at early (ER) and late (LR) harvest, respectively, and the white clover crops had 19% and 29% NDF in DM at the early (EW) and late (LW) harvest, respectively. The silages were fed restrictively (80% of ad libitum intake) twice daily to four rumen cannulated non-lactating Jersey cows (588 ± 52 kg) in a 4 × 4 Latin square design. Jaw movements (JM) were recorded for 96 h continuously. Swallowed boli, rumen mat, rumen fluid and faeces samples were collected, washed in nylon bags (0.01 mm pore size) and freeze-dried before dry sieving through 4.750, 2.360, 1.000, 0.500, 0.212 and 0.106 mm into seven fractions. The length (PL) and width (PW) values of rumen and faeces particles within each fraction were measured by use of image analysis. The eating activity (min/kg DM intake; P rumen mat (P rumen fluid (P rumen mat and faeces, but only one peak (mode 1) for PL values. There was no difference in the mean and mode 1 PW and PL value in rumen mat between the four treatments. The mean PL, mode PL, mode 2 PW and mean PW in faeces were highest for LR (P rumen mat and faeces particles are most likely related to the leaves and the stems/petioles. In conclusion, the mean total chewing activity per kg DM was lowest for the white clover silage and increased for both silages due to later harvest time. The mean particle size in boli was smallest for LR, whereas the mean PL and PW in faeces were highest for the LR.

Uptake and Distribution of Added Selenite and Selenate by Barley and Red Clover as Influenced by Sulphur

DEFF Research Database (Denmark)

Nielsen, Gunnar Gissel

1973-01-01

The uptake of added Se from selenite and selenate by barley and red clover was investigated in a pot experiment. Much more of selenate than of selenite was taken up but the Se concentrations in the plants declined more with time when selenate was the source. Increasing sulphate addition to the soil...

B-meson decay constants from 2+1-flavor lattice QCD with domain-wall light quarks and relativistic heavy quarks

Energy Technology Data Exchange (ETDEWEB)

Christ, Norman H. [Columbia Univ., New York, NY (United States); Flynn, Jonathan M. [Univ. of Southampton, Southampton (United Kingdom); Izubuchi, Taku [Brookhaven National Lab. (BNL), Upton, NY (United States); Kawanai, Taichi [RIKEN, Wako (Japan); Brookhaven National Lab. (BNL), Upton, NY (United States); Lehner, Christoph [Brookhaven National Lab. (BNL), Upton, NY (United States); Soni, Amarjit [Brookhaven National Lab. (BNL), Upton, NY (United States); Van de Water, Ruth S. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Witzel, Oliver [Boston Univ., Boston, MA (United States)

2015-03-10

We calculate the B-meson decay constants f_B, f_Bs, and their ratio in unquenched lattice QCD using domain-wall light quarks and relativistic b-quarks. We use gauge-field ensembles generated by the RBC and UKQCD collaborations using the domain-wall fermion action and Iwasaki gauge action with three flavors of light dynamical quarks. We analyze data at two lattice spacings of a ≈ 0.11, 0.086 fm with unitary pion masses as light as M_π ≈ 290 MeV; this enables us to control the extrapolation to the physical light-quark masses and continuum. For the b-quarks we use the anisotropic clover action with the relativistic heavy-quark interpretation, such that discretization errors from the heavy-quark action are of the same size as from the light-quark sector. We renormalize the lattice heavy-light axial-vector current using a mostly nonperturbative method in which we compute the bulk of the matching factor nonperturbatively, with a small correction, that is close to unity, in lattice perturbation theory. We also improve the lattice heavy-light current through O(α_sa). We extrapolate our results to the physical light-quark masses and continuum using SU(2) heavy-meson chiral perturbation theory, and provide a complete systematic error budget. We obtain f_B⁰ = 196.2(15.7) MeV, f_B⁺ = 195.4(15.8) MeV, f_Bs = 235.4(12.2) MeV, f_Bs/f_B⁰ = 1.193(59), and f_Bs/f_B⁺ = 1.220(82), where the errors are statistical and total systematic added in quadrature. In addition, these results are in good agreement with other published results and provide an important independent cross check of other three-flavor determinations of B-meson decay constants using staggered light quarks.

Lattice QCD

International Nuclear Information System (INIS)

Hasenfratz, P.

1983-01-01

The author presents a general introduction to lattice gauge theories and discusses non-perturbative methods in the gauge sector. He then shows how the lattice works in obtaining the string tension in SU(2). Lattice QCD at finite physical temperature is discussed. Universality tests in SU(2) lattice QCD are presented. SU(3) pure gauge theory is briefly dealt with. Finally, fermions on the lattice are considered. (Auth.)

Effect of microgravity on stress ethylene and carbon dioxide production in sweet clover (Melilotus alba L.)

Science.gov (United States)

Gallegos, Gregory L.; Odom, William R.; Guikema, James A.

1995-01-01

The study of higher plant growth and development in the microgravity (micro-g) environment continues to be a challenge. This is in part a result of the available flight qualified hardware with restrictive closed gas environments. This point is underscored by considering that gas exchange of seedlings grown in microgravity may be further limited owing to a thicker layer of water wicked onto the roots and to the absence of convective mixing. We hypothesized that seedlings grown under such conditions will experience greater hypoxia in microgravity than at Earth gravity, and thus produce greater stress ethylene. We compared flight and ground samples of sweet clover seedlings grown in the Fluid Processing Apparatus (FPA) during STS-57 and found them to contain extremely high levels of carbon dioxide (CO2) and stress ethylene. There were time dependent increases for both gases, and seedling growth was greatly inhibited. We repeated these experiments aboard STS-60 using modified chambers which increased, by fifty fold, the air available to the developing seedlings. Sweet clover seed germination and subsequent seedling growth to eight days within the FPA modified with a gas permeable membrane is not compromised by the microgravity environment.

Forage production in mixed grazing systems of elephant grass with arrowleaf clover or forage peanut

Directory of Open Access Journals (Sweden)

Daiane Cristine Seibt

Full Text Available ABSTRACT Most dairy production systems are pasture-based, usually consisting of sole grass species. This system facilitates pasture management, but results in high production costs, mainly because of nitrogen fertilizers. An alternative to making forage systems more sustainable is to introduce legumes into the pasture. Mixed pastures allow better forage distribution over time and reduce fertilization costs. Thus, the objective of this study was to evaluate, throughout the year, three forage systems (FS: FS1 (control - elephant grass (EG, ryegrass (RG, and spontaneous species (SS; FS2 - EG + RG + SS + arrowleaf clover; and FS3 - EG + RG + SS + forage peanut. Elephant grass was planted in rows spaced 4 m apart. Ryegrass was sown between the EG lines, in the winter. Arrowleaf clover was sown according to the respective treatments and forage peanut was preserved. Evaluation was carried out using Holstein cows. The experiment was arranged in a completely randomized design, with three treatments (FS, and three repetitions (paddocks with repeated measurements (grazing cycles. Forage mass achieved 3.46, 3.80, and 3.91 t ha-1 for the treatments FS1, FS2 and FS3, respectively. The forage systems intercropped with legumes produced the best results.

Simulating QCD at the physical point with Nf=2 Wilson twisted mass fermions at maximal twist

International Nuclear Information System (INIS)

Abdel-Rehim, A.; Alexandrou, C.; Cyprus Univ. Nicosia; Burger, F.

2015-12-01

We present simulations of QCD using N f =2 dynamical Wilson twisted mass lattice QCD with physical value of the pion mass and at one value of the lattice spacing. Such simulations at a∼0.09 fm became possible by adding the clover term to the action. While O(a) improvement is still guaranteed by Wilson twisted mass fermions at maximal twist, the introduction of the clover term reduces O(a 2 ) cutoff effects related to isospin symmetry breaking. We give results for a set of phenomenologically interesting observables like pseudo-scalar masses and decay constants, quark masses and the anomalous magnetic moments of leptons. We mostly find remarkably good agreement with phenomenology, even though we cannot take the continuum and thermodynamic limits.

Probing the dynamic response of antivortex, interstitial and trapped vortex lattices on magnetic periodic pinning potentials

International Nuclear Information System (INIS)

Gomez, A; Gonzalez, E M; Vicent, J L; Gilbert, D A; Liu Kai; Milošević, M V

2013-01-01

The dynamics of the pinned vortex, antivortex and interstitial vortex have been studied in superconducting/magnetic hybrids consisting of arrays of Co/Pd multilayer nanodots embedded in Nb films. The magnetic nanodots show out-of-plane magnetization at the remanent state. This magnetic state allows for superconducting vortex lattices of different types in an applied homogeneous magnetic field. We experimentally and theoretically show three such lattices: (i) a lattice containing only antivortices; (ii) a vortex lattice entirely pinned on the dots; and (iii) a vortex lattice with pinned and interstitial vortices. Between the flux creep (low vortex velocity) and the free flux flow (high vortex velocity) regimes the interaction between the magnetic array and the vortex lattice governs the vortex dynamics, which in turn enables distinguishing experimentally the type of vortex lattice which governs the dissipation. We show that the vortex lattice with interstitial vortices has the highest onset velocity where the lattice becomes ordered, whereas the pinned vortex lattice has the smallest onset velocity. Further, for this system, we directly estimate that the external force needed to depin vortices is 60% larger than the one needed to depin antivortices; therefore we are able to decouple the antivortex–vortex motion. (paper)

A note on the effects of paddock size on the white clover content of swards grazed by sheep

NARCIS (Netherlands)

Wolf, de P.L.; Schulte, R.P.O.; Lantinga, E.A.

2004-01-01

The maintenance of a high white clover content in mixed swards under sheep grazing has been a challenge to date. This paper presents the results of an experiment in which the effect of the length of a grazing period on the botanical composition of a mixed sward was studied. Paddocks ranging in size

Fatty acid composition of ruminal digesta and longissimus muscle from lambs fed silage mixtures including red clover, sainfoin, and timothy.

Science.gov (United States)

Campidonico, L; Toral, P G; Priolo, A; Luciano, G; Valenti, B; Hervás, G; Frutos, P; Copani, G; Ginane, C; Niderkorn, V

2016-04-01

This work investigated the effects of feeding silage mixtures of a plant containing polyphenol oxidase (PPO; red clover [; RC]), a plant containing tannins (sainfoin [; SF]), and a grass species not containing these compounds (timothy [; T]) on ruminal and intramuscular (i.m.) fatty acids of lambs. Forty 4-mo-old castrated male Romane lambs, divided into 5 groups, received 1 of the following silages: 1) T (100%), 2) a binary mixture of timothy and tannin-containing sainfoin ( cv. Perly; 50:50 [T-SF]), 3) a binary mixture of timothy and PPO-containing red clover ( cv. Mervius; 50:50 [T-RC]), 4) a ternary mixture of timothy, sainfoin, and red clover containing both tannins and PPO (50:25:25, respectively [T-SF-RC]), and 5) a binary mixture of tannin-containing sainfoin and PPO-containing red clover (50:50 [SF-RC]). In the rumen digesta, the partial or total replacement of T with forage legumes was associated with greater concentrations of PUFA ( forage legumes in the silage favored the accumulation of 18:3 -3 ( Forage legumes decreased the -11 18:1 to 30% of T in rumen digesta ( Forage legumes decreased the total concentration of branched-chain fatty acids in the rumen digesta (on average, -28%; comparison with T. The dietary treatment tended to affect the proportion of MUFA ( = 0.081) and of PUFA ( = 0.079) in the i.m. fat of the LM, respectively, at the highest and lowest numerical value in the T group. The sum of -3 fatty acids was less in the T and T-SF groups compared with the mixture of legumes without T (SF-RC; comparison with lambs given T-RC, T-SF-RC, and SF-RC. Rumenic acid (-9 -11 CLA) was detected at a greater percentage in the LM from the animals fed the T silage compared with animals fed the T-SF-RC treatment ( = 0.004). Contrarily, -9 -12 -15 18:3 was found at a greater concentration in the muscle from lambs in the SF-RC treatment compared with lambs in the other treatments ( forage for growing lambs in terms of i.m. fatty acid composition.

New uses of clover-grass mixtures in the structure of fodder crops on arable land

Directory of Open Access Journals (Sweden)

Jiří Sláma

2010-01-01

Full Text Available The use of clover-grasses in the structure of fodder crops grown on arable soil, especially those with intergeneric hybrids as the main component part, could avert the negative current trend, i.e. further decreasing the area of perennial fodder plants or fodder crops as a whole on arable soil. They have an irreplaceable role in crop sequences and in preserving the cultural character of the countryside, above all due to the fact that they improve soil fertility and microbial life in the soil and that they have an excellent pre-produce value, and, at the same time, they are applied in various farming systems (both conventional and ecological and in various climatic conditions, and agricultural businesses are well equipped for growing, harvesting and storing them. In the Czech Republic, the area of fodder crops grown on arable soil was decreased from 1,019.9 thousand hectares to mere 396.7 thousand hectares between 1980 and 2009, which is 15.6 % of the total area of arable soil whereas perennial fodder plants only take up 8.5 %. Fodder from clover crops and clover-grass growths on arable soil are one of the main resources of voluminous fodder for dairy cows. Most of this fodder is preserved through a fermentation process (silages, hay storage; a smaller part is fed as fresh fodder, or serves for production of hay. Silages made with perennial fodder plants are the most important source of both proteins and other nutrients for ruminants, especially for high-yielding milch cows. The basis of fodder production systems are the conservative elements of the landscape area (geomorphology in combination with the progressive elements (weather conditions, plants and human labour and relict ones, the representative of which is the soil. The fodder production systems in Europe are divided into five main fodder production zones. From this point of view, the areas where short-term clover-grass mixtures are grown on arable soil could be classed with Zone 4, i

Lattice-induced nonadiabatic frequency shifts in optical lattice clocks

International Nuclear Information System (INIS)

Beloy, K.

2010-01-01

We consider the frequency shift in optical lattice clocks which arises from the coupling of the electronic motion to the atomic motion within the lattice. For the simplest of three-dimensional lattice geometries this coupling is shown to affect only clocks based on blue-detuned lattices. We have estimated the size of this shift for the prospective strontium lattice clock operating at the 390-nm blue-detuned magic wavelength. The resulting fractional frequency shift is found to be on the order of 10 -18 and is largely overshadowed by the electric quadrupole shift. For lattice clocks based on more complex geometries or other atomic systems, this shift could potentially be a limiting factor in clock accuracy.

Quantitative historical change in bumblebee (Bombus spp. assemblages of red clover fields.

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Yoko L Dupont

Full Text Available BACKGROUND: Flower visiting insects provide a vitally important pollination service for many crops and wild plants. Recent decline of pollinating insects due to anthropogenic modification of habitats and climate, in particular from 1950's onwards, is a major and widespread concern. However, few studies document the extent of declines in species diversity, and no studies have previously quantified local abundance declines. We here make a quantitative assessment of recent historical changes in bumblebee assemblages by comparing contemporary and historical survey data. METHODOLOGY/PRINCIPAL FINDINGS: We take advantage of detailed, quantitative historical survey data from the 1930's on bumblebee (Bombus spp. abundances and species composition in red clover (Trifolium pratense fields, an important floral resource and an attractant of all bumblebee species. We used the historical survey data as a pre-industrialization baseline, and repeated the same sampling protocol at nearly the same localities at present, hence setting up a historical experiment. We detected historical changes in abundances (bees/m(2 of both workers (the "pollinatory units" and queens (effective population size, in addition to species composition. In particular, long-tongued bumblebee species showed consistent and dramatic declines in species richness and abundances throughout the flowering season of red clover, while short-tongued species were largely unaffected. Of 12 Bombus species observed in the 1930's, five species were not observed at present. The latter were all long-tongued, late-emerging species. CONCLUSIONS/SIGNIFICANCE: Because bumblebees are important pollinators, historical changes in local bumblebee assemblages are expected to severely affect plant reproduction, in particular long-tubed species, which are pollinated by long-tongued bumblebees.

Effect of digestibility of grass-clover silage and concentrate to forage ratio on methane emission from dairy cows

DEFF Research Database (Denmark)

Hellwing, Anne Louise Frydendahl; Weisbjerg, Martin Riis

and D, respectively. TMR forage DM consisted of 2/3 of one of the respective grass-clover silages and 1/3 maize silage, and concentrate (soya meal and wheat) proportion of DM was 20% (low) or 50% (high). Methane emissions from the cows were measured 20-22 hours in one of four chambers working after...

The influence of phosphorus deficiency on growth and nitrogen fixation of white clover plants

OpenAIRE

Høgh-Jensen, Dr Henning; Schjoerring, Dr Jan K.; Soussana, Dr Jean-Francois

2002-01-01

The effects of P deficiency on growth, N2‐fixation and photosynthesis in white clover (Trifolium repens L.) plants were investigated using three contrasting relative addition rates of P, or following abrupt withdrawal of the P supply. Responses to a constant below‐optimum P supply rate consisted of a decline in N2‐fixation per unit root weight and a small reduction in the efficiency with which electrons were allocated to the reduction of N2 in nodules. Abrupt removal of P arrested nodule grow...

B-Parameters of 4-Fermion Operators from Lattice QCD

International Nuclear Information System (INIS)

Gupta, Rajan

1997-07-01

This talk summarizes the status of the calculations of B K , B 7 , B 8 , and B s , done in collaboration with T. Bhattacharya, C. Kilcup, and S. Sharpe. Results for staggered, Wilson, and Clover fermions are presented

Nuclear analysis of the experimental VHTR fuel lattice

International Nuclear Information System (INIS)

Doi, Takeshi; Shindo, Ryuiti; Hirano, Mitsumasa; Takano, Makoto

1984-11-01

Nuclear properties of a fuel lattice in the experimental VHTR core were analyzed with DELIGHT-6 and SRAC codes. Analytical results by both codes were compared by using various calculational model. The nuclear parameters were analyzed, such as a multiplication factor of a fuel lattice and it's variation with burnup, a temperature effect on reactivity, an effect of double-heterogeniety in a resonance absorption calculation, a resonance integral of 238 U and a reactivity worth of burnable poison. From these analyses, following results were obtained. Firstly, on calculational models, 1) Effect of double-heterogeniety in the resonance absorption calculation for Mark-III fuel element, causing a decrease of about 5.5 barns in the resonance integral and an increase of about 2.6 %ΔK in the infinite multiplication factor, 2) The heterogeneous calculation with the collision probability method resulted in about 0.6 %ΔK higher the multiplication factor of fuel lattice than that with the point model, 3) The reactivity worth of burnable poison rod by a multi-region model is about 20 % less than that by a 2-region model at an initial state of burnup and it's variation with burnup are fairly different, Secondly, on comparison between the results by DELIGHT-6 and SRAC, 4) The nuclear parameters obtained with both codes agreed well, Lastly, on the improvement in DELIGHT-6, 5) Consideration of the neutron spectrum shielding effect in the resonance effective cross section calculation caused a decrease of about 2.4 %ΔK in the multiplication factor of fuel lattice, 6) The lattice multiplication factor increased about 0.5 %ΔK by introducing lambda-parameters for the non-resonant nuclie. (J.P.N.)

A study of the wet deposit and foliar uptake of iodine and strontium on rye-grass and clover

International Nuclear Information System (INIS)

Angeletti, Livio; Levi, Emilio; Commission of the European Communities, Ispra

1977-12-01

Foliar uptake of iodine and strontium by rye-grass and clover was studied as a function of aspersion intensities. At the same time, the contribution of root sorption to foliar uptake was measured. The effective half-lives of radionuclides of standing and harvested grass were also determined together with their uptake under the action of demineralized water aspersion [fr

Lattice strings

International Nuclear Information System (INIS)

Thorn, C.B.

1988-01-01

The possibility of studying non-perturbative effects in string theory using a world sheet lattice is discussed. The light-cone lattice string model of Giles and Thorn is studied numerically to assess the accuracy of ''coarse lattice'' approximations. For free strings a 5 by 15 lattice seems sufficient to obtain better than 10% accuracy for the bosonic string tachyon mass squared. In addition a crude lattice model simulating string like interactions is studied to find out how easily a coarse lattice calculation can pick out effects such as bound states which would qualitatively alter the spectrum of the free theory. The role of the critical dimension in obtaining a finite continuum limit is discussed. Instead of the ''gaussian'' lattice model one could use one of the vertex models, whose continuum limit is the same as a gaussian model on a torus of any radius. Indeed, any critical 2 dimensional statistical system will have a stringy continuum limit in the absence of string interactions. 8 refs., 1 fig. , 9 tabs

Mössbauer investigations to characterize Fe lattice sites in sheet silicates and Peru Basin deep-sea sediments

Science.gov (United States)

Lougear, André; König, Iris; Trautwein, Alfred X.; Suess, Erwin

A procedure to classify different Fe lattice sites, i.e., OH-group geometries, in the clay mineral content of deep-sea sediments was developed using Mössbauer spectroscopy at low temperature (77 K). This speciation is of interest with regard to the redox behavior, reactivity and color of marine sediments, since substantial iron redox transitions (associated with sediment color change) have been documented for the structural sheet silicate iron. Lattice site classification was achieved for the Fe(II) fraction, all of which is structural clay Fe(II) in the sediments under investigation. Whereas the major part of the Fe(III) is structural clay iron as well, there is a small Fe(III) fraction in oxide minerals. Therefore, further elaboration of the procedure would be required to also achieve lattice site classification for the Fe(III) fraction. Analysis of the Mössbauer spectra is based on computer fits, the input parameters of which were derived from a separate study of Fe(II)-rich pure chlorites. The procedure of classification is qualified to investigate, e.g., in laboratory experiments, the site-specific reaction rates and the effects on sediment color of iron redox transitions in the sheet silicate content of sediments. The new skills were successfully applied in environmental impact studies on the mining of polymetallic nodules from the Peru Basin deep-sea floor.

Systematic construction of spin liquids on the square lattice from tensor networks with SU(2) symmetry

Science.gov (United States)

Mambrini, Matthieu; Orús, Román; Poilblanc, Didier

2016-11-01

We elaborate a simple classification scheme of all rank-5 SU(2) spin rotational symmetric tensors according to (i) the onsite physical spin S , (ii) the local Hilbert space V⊗4 of the four virtual (composite) spins attached to each site, and (iii) the irreducible representations of the C4 v point group of the square lattice. We apply our scheme to draw a complete list of all SU(2)-symmetric translationally and rotationally invariant projected entangled pair states (PEPS) with bond dimension D ≤6 . All known SU(2)-symmetric PEPS on the square lattice are recovered and simple generalizations are provided in some cases. More generally, to each of our symmetry class can be associated a (D -1 )-dimensional manifold of spin liquids (potentially) preserving lattice symmetries and defined in terms of D -independent tensors of a given bond dimension D . In addition, generic (low-dimensional) families of PEPS explicitly breaking either (i) particular point-group lattice symmetries (lattice nematics) or (ii) time-reversal symmetry (chiral spin liquids) or (iii) SU(2) spin rotation symmetry down to U(1 ) (spin nematics or Néel antiferromagnets) can also be constructed. We apply this framework to search for new topological chiral spin liquids characterized by well-defined chiral edge modes, as revealed by their entanglement spectrum. In particular, we show how the symmetrization of a double-layer PEPS leads to a chiral topological state with a gapless edge described by a SU (2) 2 Wess-Zumino-Witten model.

Microbial biomass, microbial diversity, soil carbon storage, and stability after incubation of soil from grass-clover pastures of different age

DEFF Research Database (Denmark)

Müller-Stöver, Dorette Sophie; Hauggaard-Nielsen, Henrik; Eriksen, Jørgen

2012-01-01

A laboratory incubation study with clover grass pasture soils of seven different ages (0, 1, 2, 3, 4, 5, and 16 production years) was carried out to determine initial soil carbon (C) and nitrogen (N) stocks and potentials for greenhouse gas emissions (N2O and CO2). Compared with the soil from...... the recently established pasture, an increase of total soil C and N was observed along with pasture age. Greenhouse gas emissions were low and not significantly different among the soils from younger pastures (0-5 years), but especially N2O emissions increased markedly in the soil from 16-year-old grass......-clover. Low emissions might mainly be due to an early C limitation occurring in the soils from younger pastures, which was also corroborated by decreasing levels of cold water-extractable C and early shifts within the microbial community. However, higher emissions from the old pasture soil were offset by its...

Electronic structure and lattice properties of metastable III-(N,V) semiconductor systems; Elektronische Struktur und Kristallgittereigenschaften von metastabilen III-(N,V)-Halbleitersystemen

Energy Technology Data Exchange (ETDEWEB)

Guengerich, M.

2007-12-18

This thesis gives an overview of these influences for Ga-V semiconductors (V=P,As,Sb). Lattice vibrations of the ternary alloys Ga(N,P), Ga(N,As) und Ga(N,Sb) are studied and analyzed with respect to the local binding of the N atoms in the host lattices. For the first time, pressure coefficients of the extended host phonons as well as of the N local vibrational modes in Ga(N,As) und Ga(N,P) are determined by Raman spectroscopy under hydrostatic pressure. The relationship between the force constant of the Ga-N bond and the bond length is determined. A central aspect of the thesis is the concentration dependence of optical transitions in Ga(N,P) and Ga(N,As), studied by spectroscopic methods. The impurity levels in both materials are determined by the spatial statistics of the N atoms. (orig.)

The beneficial effect of dual inoculation of vesicular-arbuscular mycorrhizae + rhizobium on growth of white clover

OpenAIRE

Lin, XG.; Hao, WY.; Wu, TH.

1993-01-01

Investigation on the effect of phosphorus on vesicular-arbuscular mycorrhizal infection, and dual inoculation of vesicular-arbuscular mycorrhizae + rhizobium on growth of white clover under field microplots and pot experiments was conducted on fluvo-aquic soils of semi-arid region in north China. The results showed that 60 kg P205 ha in form of superphosphate was the most favorable phosphorus level for vesicular-arbuscular mycorrhizal infection ; mycorrhizal infection, nodulation, dry weight ...

Identification of an extensive gene cluster among a family of PPOs in Trifolium pratense L. (red clover using a large insert BAC library

Directory of Open Access Journals (Sweden)

Thomas Ann

2009-07-01

Full Text Available Abstract Background Polyphenol oxidase (PPO activity in plants is a trait with potential economic, agricultural and environmental impact. In relation to the food industry, PPO-induced browning causes unacceptable discolouration in fruit and vegetables: from an agriculture perspective, PPO can protect plants against pathogens and environmental stress, improve ruminant growth by increasing nitrogen absorption and decreasing nitrogen loss to the environment through the animal's urine. The high PPO legume, red clover, has a significant economic and environmental role in sustaining low-input organic and conventional farms. Molecular markers for a range of important agricultural traits are being developed for red clover and improved knowledge of PPO genes and their structure will facilitate molecular breeding. Results A bacterial artificial chromosome (BAC library comprising 26,016 BAC clones with an average 135 Kb insert size, was constructed from Trifolium pratense L. (red clover, a diploid legume with a haploid genome size of 440–637 Mb. Library coverage of 6–8 genome equivalents ensured good representation of genes: the library was screened for polyphenol oxidase (PPO genes. Two single copy PPO genes, PPO4 and PPO5, were identified to add to a family of three, previously reported, paralogous genes (PPO1–PPO3. Multiple PPO1 copies were identified and characterised revealing a subfamily comprising three variants PPO1/2, PPO1/4 and PPO1/5. Six PPO genes clustered within the genome: four separate BAC clones could be assembled onto a predicted 190–510 Kb single BAC contig. Conclusion A PPO gene family in red clover resides as a cluster of at least 6 genes. Three of these genes have high homology, suggesting a more recent evolutionary event. This PPO cluster covers a longer region of the genome than clusters detected in rice or previously reported in tomato. Full-length coding sequences from PPO4, PPO5, PPO1/5 and PPO1/4 will facilitate

Amino acid profile of metabolisable protein in lactating dairy cows is affected by dry matter concentration in grass-clover silage

DEFF Research Database (Denmark)

Johansen, Marianne; Lund, Peter; Weisbjerg, Martin Riis

2018-01-01

Our previous study showed that supply of metabolisable protein (MP) to lactating dairy cows increased with increasing dry matter (DM) concentration in grass-clover silage. The aim of this study was to examine how amino acid (AA) profile of MP was affected by silage DM concentration. Eight grass-c...

The clover technique for the treatment of complex tricuspid valve insufficiency: midterm clinical and echocardiographic results in 66 patients.

Science.gov (United States)

Lapenna, Elisabetta; De Bonis, Michele; Verzini, Alessandro; La Canna, Giovanni; Ferrara, David; Calabrese, Maria Chiara; Taramasso, Maurizio; Alfieri, Ottavio

2010-06-01

This study assesses the results of the 'clover technique' (suturing together the middle point of the free edges of the tricuspid leaflets) for the treatment of tricuspid regurgitation (TR) due to severe prolapse or tethering. From 2001, 66 patients with severe TR due to prolapsing or tethered leaflets underwent 'clover repair'. Annuloplasty was associated in 64 patients (97%). The aetiology of TR was degenerative in 52 cases (79%), post-traumatic in eight (12%) and secondary to dilated cardiomyopathy (DCM) in six (9%). The main mechanism of TR was prolapse/flail of one leaflet in 15 patients (23%), of two leaflets in 31 (47%) and of all three leaflets in 14 (21%). The remaining six patients (9%) presented with severe leaflets' tethering. Four deaths (6%) occurred during hospitalisation and one patient died 3.6 years after surgery. Survival was 91 + or - 4.1% at 5 years. Follow-up of the 62 hospital survivors was 100% complete (mean length 3.5 + or - 1.6 years, range 13 months-7.1 years). At the last echocardiogram, no or mild TR was detected in 55 (88.7%) patients, moderate (2+/4+) in six (9.6%) and severe (4+/4+) in one patient (1.6%). Mean tricuspid valve area and gradient were 4.3 + or - 0.6 cm(2) and 2.8 + or -1.4 mmHg. In six patients, stress echocardiography was performed and no signs of tricuspid stenosis were detected. At the multivariable analysis, the degree of TR at hospital discharge was identified as the only predictor of TR > or = 2+ at follow-up. Midterm clinical and echocardiographic results confirm the role of the 'clover technique' in the surgical treatment of TR due to lesions, which are unlikely to be effectively treatable by annuloplasty alone. Copyright 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

Forage fiber effects on particle size reduction, ruminal stratification, and selective retention in heifers fed highly digestible grass/clover silages.

Science.gov (United States)

Schulze, A K S; Weisbjerg, M R; Storm, A C; Nørgaard, P

2014-06-01

The objective of this study was to investigate the effect of NDF content in highly digestible grass/clover silage on particle size reduction, ruminal stratification, and selective retention in dairy heifers. The reduction in particle size from feed to feces was evaluated and related to feed intake, chewing activity, and apparent digestibility. Four grass/clover harvests (Mixtures of Lolium perenne, Trifolium pratense, and Trifolium repens) were performed from early May to late August at different maturities, at different regrowth stages, and with different clover proportions, resulting in silages with NDF contents of 312, 360, 371, and 446 g/kg DM, respectively, and decreasing NDF digestibility with greater NDF content. Four rumen-fistulated dairy heifers were fed silage at 90% of ad libitum level as the only feed source in a 4 × 4 Latin square design. Silage, ingested feed boluses, medial and ventral ruminal digesta, and feces samples were washed with neutral detergent in nylon bags of 10-μm pore size, freeze dried, and divided into small (1 mm) particles by dry-sieving. Chewing activity, rumen pool size, and apparent digestibility were measured. Intake of NDF increased linearly from 2.3 to 2.8 kg/d with greater NDF content of forages (P = 0.01), but silages were exposed to similar eating time (P = 0.55) and rumination time per kg NDF (P = 0.35). No linear effect of NDF content was found on proportion of LP in ingested feed boluses (P = 0.31), medial rumen digesta (P = 0.95), ventral rumen digesta (P = 0.84), and feces (P = 0.09). Greater proportions of DM (P ruminal digesta compared with ventral rumen, and differences in DM proportion increased with greater NDF content (P = 0.02). Particle size distributions were similar for digesta from the medial and ventral rumen regardless of NDF content of the silages (P > 0.13). The LP proportion was >30% of particles in the ventral and medial rumen, whereas in the feces, the LP proportion was content of the silages

78 FR 22425 - Designation of Areas for Air Quality Planning Purposes; State of Nevada; Total Suspended Particulate

Science.gov (United States)

2013-04-16

... Valley, Fernley Area, Mason Valley, and Clovers Area. EPA is taking this action under the Clean Air Act... Reese Valley, Fernley Area, Mason Valley, and Clovers Area III. Final Action and Request for Comment IV... Reese Valley (HA 59), Gabbs Valley (HA 122), Fernley Area (HA 76), Truckee Meadows (HA 87), Mason Valley...

Generalized isothermic lattices

International Nuclear Information System (INIS)

Doliwa, Adam

2007-01-01

We study multi-dimensional quadrilateral lattices satisfying simultaneously two integrable constraints: a quadratic constraint and the projective Moutard constraint. When the lattice is two dimensional and the quadric under consideration is the Moebius sphere one obtains, after the stereographic projection, the discrete isothermic surfaces defined by Bobenko and Pinkall by an algebraic constraint imposed on the (complex) cross-ratio of the circular lattice. We derive the analogous condition for our generalized isothermic lattices using Steiner's projective structure of conics, and we present basic geometric constructions which encode integrability of the lattice. In particular, we introduce the Darboux transformation of the generalized isothermic lattice and we derive the corresponding Bianchi permutability principle. Finally, we study two-dimensional generalized isothermic lattices, in particular geometry of their initial boundary value problem

Elimination of spurious lattice fermion solutions and noncompact lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Lee, T.D.

1997-09-22

It is well known that the Dirac equation on a discrete hyper-cubic lattice in D dimension has 2{sup D} degenerate solutions. The usual method of removing these spurious solutions encounters difficulties with chiral symmetry when the lattice spacing l {ne} 0, as exemplified by the persistent problem of the pion mass. On the other hand, we recall that in any crystal in nature, all the electrons do move in a lattice and satisfy the Dirac equation; yet there is not a single physical result that has ever been entangled with a spurious fermion solution. Therefore it should not be difficult to eliminate these unphysical elements. On a discrete lattice, particle hop from point to point, whereas in a real crystal the lattice structure in embedded in a continuum and electrons move continuously from lattice cell to lattice cell. In a discrete system, the lattice functions are defined only on individual points (or links as in the case of gauge fields). However, in a crystal the electron state vector is represented by the Bloch wave functions which are continuous functions in {rvec {gamma}}, and herein lies one of the essential differences.

Perovskites A/sub 2/sup(II)Bsub(0. 5)sup(I)Bsub(0. 5)sup(III)Wsup(VI)O/sub 6/

Energy Technology Data Exchange (ETDEWEB)

Roller, H; Kemmler-Sack, S [Tuebingen Univ. (Germany, F.R.). Inst. fuer Chemie

1978-05-01

Compounds of type A/sub 2/sup(II)Bsub(0.5)sup(I)Bsub(0.5)sup(III)Wsup(VI)O/sub 6/ can be obtained with Asup(II) = Ba; Bsup(I) = Li, Na and Bsup(III) = La, Nd, Sm, Gd, Y, In, Sc just as with Asup(II) = Sr; Bsup(I) = Li and Bsup(III) = La, Nd, Sm, Gd, Y, In (all cubic ordered perovskites). For the cubic perovskites Sr/sub 2/Nasub(0.5)Lasub(0.5)WO/sub 6/ and Sr/sub 2/Nasub(0.5)Ndsub(0.5)WO/sub 6/ additional superlattice reflections are observed (a approximately equal to 16.4 A). The compounds Sr/sub 2/Nasub(0.5)Bsub(0.5)sup(III)WO/sub 6/ crystallize with Bsup(III) = Sm, Gd in a monoclinic and with Bsup(III) = Y, In in a rhombic distorted perovskite lattice. For the perovskites with A = Sr - dependent on ionic radii of the B ions - two different lattice types are present.

Lattice fermions

Energy Technology Data Exchange (ETDEWEB)

Randjbar-Daemi, S

1995-12-01

The so-called doubling problem in the lattice description of fermions led to a proof that under certain circumstances chiral gauge theories cannot be defined on the lattice. This is called the no-go theorem. It implies that if {Gamma}/sub/A is defined on a lattice then its infrared limit, which should correspond to the quantum description of the classical action for the slowly varying fields on lattice scale, is inevitably a vector like theory. In particular, if not circumvented, the no-go theorem implies that there is no lattice formulation of the Standard Weinberg-Salam theory or SU(5) GUT, even though the fermions belong to anomaly-free representations of the gauge group. This talk aims to explain one possible attempt at bypassing the no-go theorem. 20 refs.

Lattice fermions

International Nuclear Information System (INIS)

Randjbar-Daemi, S.

1995-12-01

The so-called doubling problem in the lattice description of fermions led to a proof that under certain circumstances chiral gauge theories cannot be defined on the lattice. This is called the no-go theorem. It implies that if Γ/sub/A is defined on a lattice then its infrared limit, which should correspond to the quantum description of the classical action for the slowly varying fields on lattice scale, is inevitably a vector like theory. In particular, if not circumvented, the no-go theorem implies that there is no lattice formulation of the Standard Weinberg-Salam theory or SU(5) GUT, even though the fermions belong to anomaly-free representations of the gauge group. This talk aims to explain one possible attempt at bypassing the no-go theorem. 20 refs

Report on the intercomparison run IAEA-156 radionuclides in clover

International Nuclear Information System (INIS)

Strachnov, V.; Valkovic, V.; Dekner, R.

1991-01-01

This report contains the results of the intercomparison IAEA-156 on the determination of radionuclides in clover. Initially participants were requested to determine the levels of 134 Cs, 137 Cs, 40 K, 90 Sr and invited to provide data for other radionuclides. The participants included 46 laboratories located in 25 countries, and statistical evaluation of their data yield recommended values for these four radionuclides. Additional radionuclides reported were 210 Pb, 239 Pu and 125 Sb; however, insufficient data exists to statistically determine recommended values for these radionuclides. The following are the recommended values, with confidence intervals, for the most frequently measured radionuclides (reference date: 1 August 1986): 134 Cs 132.1 Bq/kg (126.4-137.7); 137 Cs 264 Bq/kg (254-274); 40 K 657 Bq/kg (637-676); 90 Sr 14.8 Bq/kg (13.4-16.3). Figs and tabs

Breeding biologies, pollinators and seed beetles of two prairie-clovers, Dalea ornata and D. searlsiae (Fabaceae: Amorpheae), from the Intermountain West USA

Science.gov (United States)

Two prairie-clovers, Dalea ornata and D. searlsiae, are perennial forbs that flower during early summer throughout the Colombia Plateau and Great Basin of the western USA, respectively. Their seed is desirable for use in rangeland restoration. We experimentally characterized the breeding biologies ...

Utilization of kura clover-reed canarygrass silage versus alfalfa silage by lactating dairy cows.

Science.gov (United States)

Kammes, K L; Heemink, G B H; Albrecht, K A; Combs, D K

2008-08-01

The mixture of kura clover (Trifolium ambiguum M. Bieb.) and reed canarygrass (Phalaris arundinacea L.) has proven to be extremely persistent in the northern United States, but information about dairy cow performance on this mixture is lacking. Twenty lactating Holstein cows were used in a crossover design to compare dry matter (DM) intake and milk production from diets containing kura clover-reed canarygrass silage (KRS) or alfalfa (Medicago sativa L.) silage (AS). Forages were cut, wilted, ensiled in horizontal plastic bags, and allowed to ferment for at least 50 d before beginning the feeding experiment. The KRS was approximately 40% kura clover and 60% reed canarygrass. Treatments were total mixed rations formulated with either 57% of total DM from 1) AS or 2) KRS. Experimental periods were 28 d, with the first 14 d for diet adaptation and the last 14 d for measurement of intake and milk production. The neutral detergent fiber (NDF) concentrations of AS and KRS were 37.3 and 47.3%, respectively. The fermentation analyses indicated that both silages underwent a restricted fermentation, producing primarily lactic acid and some acetic acid. Dry matter intake (24.2 vs. 22.8 kg) and 4% fat-corrected milk (32.8 vs. 30.9 kg) were significantly higher for cows fed AS than for cows fed KRS. Cows consumed less NDF (6.7 vs. 8.0 kg) and less digestible NDF (3.0 vs. 4.4 kg) when fed AS diets compared with KRS diets, but the pool of ruminally undegraded NDF was similar (3.7 kg) between diets. Cows produced 1.5 kg of milk/kg of DM consumed regardless of the diet, indicating that digestible NDF of KRS was utilized with similar efficiency as the cell wall constituents of AS, but the intake of cows fed KRS may have been limited by rumen fill. Milk fat concentration tended to be higher for cows fed AS, but the milk true protein concentration and yields of fat and protein did not differ by treatment. Milk urea nitrogen content was higher when cows consumed AS (16.4 mg/ d

Lattice gauge theory

International Nuclear Information System (INIS)

Mack, G.

1982-01-01

After a description of a pure Yang-Mills theory on a lattice, the author considers a three-dimensional pure U(1) lattice gauge theory. Thereafter he discusses the exact relation between lattice gauge theories with the gauge groups SU(2) and SO(3). Finally he presents Monte Carlo data on phase transitions in SU(2) and SO(3) lattice gauge models. (HSI)

Climate Clever Clovers: New Paradigm to Reduce the Environmental Footprint of Ruminants by Breeding Low Methanogenic Forages Utilizing Haplotype Variation

Directory of Open Access Journals (Sweden)

Parwinder Kaur

2017-09-01

Full Text Available Mitigating methane production by ruminants is a significant challenge to global livestock production. This research offers a new paradigm to reduce methane emissions from ruminants by breeding climate-clever clovers. We demonstrate wide genetic diversity for the trait methanogenic potential in Australia’s key pasture legume, subterranean clover (Trifolium subterraneum L.. In a bi-parental population the broadsense heritability in methanogenic potential was moderate (H2 = 0.4 and allelic variation in a region of Chr 8 accounted for 7.8% of phenotypic variation. In a genome-wide association study we identified four loci controlling methanogenic potential assessed by an in vitro fermentation system. Significantly, the discovery of a single nucleotide polymorphism (SNP on Chr 5 in a defined haplotype block with an upstream putative candidate gene from a plant peroxidase-like superfamily (TSub_g18548 and a downstream lectin receptor protein kinase (TSub_g18549 provides valuable candidates for an assay for this complex trait. In this way haplotype variation can be tracked to breed pastures with reduced methanogenic potential. Of the quantitative trait loci candidates, the DNA-damage-repair/toleration DRT100-like protein (TSub_g26967, linked to avoid the severity of DNA damage induced by secondary metabolites, is considered central to enteric methane production, as are disease resistance (TSub_g26971, TSub_g26972, and TSub_g18549 and ribonuclease proteins (TSub_g26974, TSub_g26975. These proteins are good pointers to elucidate the genetic basis of in vitro microbial fermentability and enteric methanogenic potential in subterranean clover. The genes identified allow the design of a suite of markers for marker-assisted selection to reduce rumen methane emission in selected pasture legumes. We demonstrate the feasibility of a plant breeding approach without compromising animal productivity to mitigate enteric methane emissions, which is one of the most

Effect of toasting field beans and of grass-clover

DEFF Research Database (Denmark)

Mogensen, Lisbeth; Vestergaard, Jannie Steensig; Fretté, Xavier

2010-01-01

The effect of toasting field beans and of grass-clover: maize silage ratio on milk production, milk composition and the sensory quality of the milk was investigated in a 2   2 factorial experiment. Toasting of field beans resulted in lower milk contents of both fat (44.2 versus 46.1 g/kg, P = 0.......02) and protein (33.5 versus 34.2 g/kg, P = 0.008), whereas milk production, urea and somatic cell contents were unaffected compared with the untreated field beans. Increasing the proportion of maize silage (from 9 to 21% of DM) in the ration decreased the content of urea in milk (P = 0.002), whereas milk......-β-carotene (P = 0.04) and β-carotene (P = 0.05). Toasting of field beans compared with untreated field beans did not affect the milk content of carotenoids and had only small effects on fatty acid composition. Regarding the sensory quality, the four treatments resulted in milk being characterized...

From lattice Hamiltonians to tunable band structures by lithographic design

Science.gov (United States)

Tadjine, Athmane; Allan, Guy; Delerue, Christophe

2016-08-01

Recently, new materials exhibiting exotic band structures characterized by Dirac cones, nontrivial flat bands, and band crossing points have been proposed on the basis of effective two-dimensional lattice Hamiltonians. Here, we show using atomistic tight-binding calculations that these theoretical predictions could be experimentally realized in the conduction band of superlattices nanolithographed in III-V and II-VI semiconductor ultrathin films. The lithographed patterns consist of periodic lattices of etched cylindrical holes that form potential barriers for the electrons in the quantum well. In the case of honeycomb lattices, the conduction minibands of the resulting artificial graphene host several Dirac cones and nontrivial flat bands. Similar features, but organized in different ways, in energy or in k -space are found in kagome, distorted honeycomb, and Lieb superlattices. Dirac cones extending over tens of meV could be obtained in superlattices with reasonable sizes of the lithographic patterns, for instance in InAs/AlSb heterostructures. Bilayer artificial graphene could be also realized by lithography of a double quantum-well heterostructure. These new materials should be interesting for the experimental exploration of Dirac-based quantum systems, for both fundamental and applied physics.

Effects of forest management on running buffalo clover (Trifolium stoloniferum Muhl. Ex A. Eaton) distribution and abundance in the Fernow Experimental Forest

Science.gov (United States)

J.Q. Burkhart; J.R. Rentch; T.M. Schuler

2013-01-01

Identifying habitat preferences of species of concern is fundamental to the practice of conservation, but disturbances and other environmental processes can substantially affect suitability. Trifolium stoloniferum, or running buffalo clover, is a federally endangered plant species that occurs on the Fernow Experimental Forest in West Virginia....

Annual maize and perennial grass-clover strip cropping for increased resource use efficiency and productivity using organic farming practice as a model

DEFF Research Database (Denmark)

Hauggaard-Nielsen, Henrik; Johansen, Anders; Carter, Mette Sustmann

2013-01-01

A cropping system was designed to fulfill the increasing demand for biomass for food and energy without decreasing long term soil fertility. A field experiment was carried out including alternating strips of annual maize (Zea mays L.) and perennial ryegrass (Lolium perenne L.) – clover (Trifolium...

Measured and simulated performance of Compton-suppressed TIGRESS HPGe clover detectors

Science.gov (United States)

Schumaker, M. A.; Hackman, G.; Pearson, C. J.; Svensson, C. E.; Andreoiu, C.; Andreyev, A.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Boston, A. J.; Chakrawarthy, R. S.; Churchman, R.; Drake, T. E.; Finlay, P.; Garrett, P. E.; Grinyer, G. F.; Hyland, B.; Jones, B.; Maharaj, R.; Morton, A. C.; Phillips, A. A.; Sarazin, F.; Scraggs, H. C.; Smith, M. B.; Valiente-Dobón, J. J.; Waddington, J. C.; Watters, L. M.

2007-01-01

Tests of the performance of a 32-fold segmented HPGe clover detector coupled to a 20-fold segmented Compton-suppression shield, which form a prototype element of the TRIUMF-ISAC Gamma-Ray Escape-Suppressed Spectrometer (TIGRESS), have been made. Peak-to-total ratios and relative efficiencies have been measured for a variety of γ-ray energies. These measurements were used to validate a GEANT4 simulation of the TIGRESS detectors, which was then used to create a simulation of the full 12-detector array. Predictions of the expected performance of TIGRESS are presented. These predictions indicate that TIGRESS will be capable, for single 1 MeV γ rays, of absolute detection efficiencies of 17% and 9.4%, and peak-to-total ratios of 54% and 61% for the "high-efficiency" and "optimized peak-to-total" configurations of the array, respectively.

Area of Lattice Polygons

Science.gov (United States)

Scott, Paul

2006-01-01

A lattice is a (rectangular) grid of points, usually pictured as occurring at the intersections of two orthogonal sets of parallel, equally spaced lines. Polygons that have lattice points as vertices are called lattice polygons. It is clear that lattice polygons come in various shapes and sizes. A very small lattice triangle may cover just 3…

Calculating lattice thermal conductivity: a synopsis

Science.gov (United States)

Fugallo, Giorgia; Colombo, Luciano

2018-04-01

We provide a tutorial introduction to the modern theoretical and computational schemes available to calculate the lattice thermal conductivity in a crystalline dielectric material. While some important topics in thermal transport will not be covered (including thermal boundary resistance, electronic thermal conduction, and thermal rectification), we aim at: (i) framing the calculation of thermal conductivity within the general non-equilibrium thermodynamics theory of transport coefficients, (ii) presenting the microscopic theory of thermal conduction based on the phonon picture and the Boltzmann transport equation, and (iii) outlining the molecular dynamics schemes to calculate heat transport. A comparative and critical addressing of the merits and drawbacks of each approach will be discussed as well.

Electrical properties of dislocations in III-Nitrides

Energy Technology Data Exchange (ETDEWEB)

Cavalcoli, D.; Minj, A.; Pandey, S.; Cavallini, A. [Physics and Astronomy Dept. University of Bologna, Italy viale C Berti Pichat 6/II, Bologna (Italy)

2014-02-21

Research on GaN, AlN, InN (III-N) and their alloys is achieving new heights due their high potential applications in photonics and electronics. III-N semiconductors are mostly grown epitaxially on sapphire, and due to the large lattice mismatch and the differences in the thermal expansion coefficients, the structures usually contain many threading dislocations (TDs). While their structural properties have been widely investigated, their electrical characteristics and their role in the transport properties of the devices are still debated. In the present contribution we will show conductive AFM studies of TDs in GaN and Al/In GaN ternary alloys to evidence the role of strain, different surface polarity and composition on their electrical properties. Local I-V curves measured at TDs allowed us to clarify their role in the macroscopic electrical properties (leakage current, mobilities) of III-N based devices. Samples obtained by different growers (AIXTRON, III-V Lab) were studied. The comparison between the results obtained in the different alloys allowed us to understand the role of In and Al on the TDs electrical properties.

Electrical properties of dislocations in III-Nitrides

Science.gov (United States)

Cavalcoli, D.; Minj, A.; Pandey, S.; Cavallini, A.

2014-02-01

Research on GaN, AlN, InN (III-N) and their alloys is achieving new heights due their high potential applications in photonics and electronics. III-N semiconductors are mostly grown epitaxially on sapphire, and due to the large lattice mismatch and the differences in the thermal expansion coefficients, the structures usually contain many threading dislocations (TDs). While their structural properties have been widely investigated, their electrical characteristics and their role in the transport properties of the devices are still debated. In the present contribution we will show conductive AFM studies of TDs in GaN and Al/In GaN ternary alloys to evidence the role of strain, different surface polarity and composition on their electrical properties. Local I-V curves measured at TDs allowed us to clarify their role in the macroscopic electrical properties (leakage current, mobilities) of III-N based devices. Samples obtained by different growers (AIXTRON, III-V Lab) were studied. The comparison between the results obtained in the different alloys allowed us to understand the role of In and Al on the TDs electrical properties.

Negative-Parity Baryon Masses Using O(a)-improved Fermion Action

Energy Technology Data Exchange (ETDEWEB)

M. Gockeler; R. Horsley; D. Pleiter; P.E.L. Rakow; G. Schierholz; C.M. Maynard; D.G. Richards

2001-06-01

We present a calculation of the mass of the lowest-lying negative-parity J=1/2{sup {minus}} state in quenched QCD. Results are obtained using a non-perturbatively {Omicron}(a)-improved clover fermion action, and a splitting found between the masses of the nucleon, and its parity partner. The calculation is performed on two lattice volumes, and at three lattice spacings, enabling a study of both finite-volume and finite lattice-spacing uncertainties. A comparison is made with results obtained using the unimproved Wilson fermion action.

Negative-parity baryon masses using an Ο(α)-improved fermion action

International Nuclear Information System (INIS)

Goeckeler, M.; Rakow, P.E.L.; Maynard, C.M.; Richards, D.G.; Old Dominion Univ., Norfolk, VA

2001-06-01

We present a calculation of the mass of the lowest-lying negative-parity J = 1/2 - state in quenched QCD. Results are obtained using a non-perturbatively O(a)-improved clover fermion action, and a splitting is found between the masses of the nucleon, and its parity partner. The calculation is performed on two lattice volumes and at three lattice spacings, enabling a study of both finite-volume and finite lattice-spacing uncertainties. A comparison is made with results obtained using the unimproved Wilson fermion action. (orig.)

Masses and decay constants of the Ds0 *(2317 ) and Ds 1(2460 ) from Nf=2 lattice QCD close to the physical point

Science.gov (United States)

Bali, Gunnar S.; Collins, Sara; Cox, Antonio; Schäfer, Andreas; RQCD Collaboration

2017-10-01

We perform a high statistics study of the JP=0+ and 1+ charmed-strange mesons, Ds0 *(2317 ) and Ds 1(2460 ), respectively. The effects of the nearby D K and D*K thresholds are taken into account by employing the corresponding four-quark operators. Six ensembles with Nf=2 nonperturbatively O (a ) improved clover Wilson sea quarks at a =0.07 fm are employed, covering different spatial volumes and pion masses: linear lattice extents L /a =24 , 32, 40, 64, equivalent to 1.7 fm to 4.5 fm, are realized for mπ=290 MeV and L /a =48 , 64 or 3.4 fm and 4.5 fm for an almost physical pion mass of 150 MeV. Through a phase shift analysis and the effective range approximation we determine the scattering lengths, couplings to the thresholds and the infinite-volume masses. Differences relative to the experimental values are observed for these masses, however, this is likely to be due to discretization effects as spin-averaged quantities and splittings are reasonably compatible with experiment. We also compute the weak decay constants of the scalar and axialvector and find fV0+=114 (2 )(0 )(+5 )(10 ) MeV and fA1+=194 (3 )(4 )(+5 )(10 ) MeV , where the errors are due to statistics, renormalization, finite-volume and lattice spacing effects.

Distribution of radionuclides in leaf-stem biomass of lupine and clover under production of protein concentrates

International Nuclear Information System (INIS)

Novikov, Yu.F.; Lobach, G.A.; Buzenko, T.A.; Zaretskaya, T.P.

1993-01-01

The basic regularities of radionuclide distribution between the obtained products have been studied using the fractionation of lupine and clover phytomass as an example. The content of radionuclides in protein concentrates has been shown to be strongly related to the crop species. A scheme and a regime of the fractionation of leaf-stem lupine biomass contaminated with cesium radioisotopes and strontium-90 which ensured the minimizing of their residual content in protein-vitaminic and protein concentrates have been selected with due accout of experimental data

The Growth Rate and Efficiency of Rumen Microbial Protein Digestion of Red Clover Silage (Trifolium pratense cv. Sabatron)

International Nuclear Information System (INIS)

Asih Kurniawati

2004-01-01

(Trifolium pratense cv. Sabatron). Red clover silage supplemented with different level of carbohydrates has been examined using the in-vitro gas production technique. Cumulative gas production, hydro.gen sulfite production, and ammonia was followed and used as indicators of microbial growth rate and extent of protein degradation. Microbial nitrogen production, VFA, and efficiency microbial production was used as indicator of nitrogen use efficiency. 15 N was used as a microbial marker to estimate the amount of nitrogen incorporation into microbial protein. Supplementation of Red clover with increasing 5 levels; 0 g; 0.625 g; 0.15 g; 0.225 g and 0.3 g of maize starch led to graded increase in microbial growth and protein degradation. This was reflected in the increasing gas production and the accumulation of hydrogen sulfite. Diurnal change in ammonia production reflected the microbial utilization of ammonia for protein synthesis. Protein microbe (P<0.001) as VFA (P<0.001) increased due to carbohydrate addition as well as utilization of nitrogen (P<0.001). There was also the efficiency of nitrogen utilization which increased significantly. This result suggested that energy supply can increased efficiency of nitrogen use in the rumen and may reduce nitrogen losses into the environment. (author)

Forage mass and the nutritive value of pastures mixed with forage peanut and red clover

Directory of Open Access Journals (Sweden)

Ricardo Lima de Azevedo Junior

2012-04-01

Full Text Available The objective of this research was to estimate three pasture-based systems mixed with elephantgrass + spontaneous growth species, annual ryegrass, for pasture-based system 1; elephantgrass + spontaneous growth species + forage peanut, for pasture-based system 2; and elephantgrass + spontaneous growth species + annual ryegrass + red clover, for pasture-based system 3. Elephantgrass was planted in rows 4 m apart from each other. During the cool-season, annual ryegrass was sown in the alleys between the rows of elephantgrass; forage peanut and red clover were sown in the alleys between the elephantgrass according to the respective treatment. The experimental design was totally randomized in the three treatments (pasture-based systems, two replicates (paddocks in completely split-plot time (grazing cycles. Holstein cows receiving 5.5 kg-daily complementary concentrate feed were used in the evaluation. Pre-grazing forage mass, botanical composition and stocking rate were evaluated. Samples of simulated grazing were collected to analyze organic matter (OM, neutral detergent fiber (NDF, crude protein (CP and organic matter in situ digestibility (OMISD. Nine grazing cycles were performed during the experimental period (341 days. The average dry matter values for pre-grazing and stocking rate were 3.34; 3.46; 3.79 t/ha, and 3.28; 3.34; 3.60 AU/ha for each respective pasture-based system. Similar results were observed between the pasture-based systems for OM, NDF, CP and OMISD. Considering forage mass, stocking rate and nutritive value, the pasture-based system intercropped with forage legumes presented better performance.

New integrable lattice hierarchies

International Nuclear Information System (INIS)

Pickering, Andrew; Zhu Zuonong

2006-01-01

In this Letter we give a new integrable four-field lattice hierarchy, associated to a new discrete spectral problem. We obtain our hierarchy as the compatibility condition of this spectral problem and an associated equation, constructed herein, for the time-evolution of eigenfunctions. We consider reductions of our hierarchy, which also of course admit discrete zero curvature representations, in detail. We find that our hierarchy includes many well-known integrable hierarchies as special cases, including the Toda lattice hierarchy, the modified Toda lattice hierarchy, the relativistic Toda lattice hierarchy, and the Volterra lattice hierarchy. We also obtain here a new integrable two-field lattice hierarchy, to which we give the name of Suris lattice hierarchy, since the first equation of this hierarchy has previously been given by Suris. The Hamiltonian structure of the Suris lattice hierarchy is obtained by means of a trace identity formula

Lattice Symmetry and Identification-The Fundamental Role of Reduced Cells in Materials Characterization.

Science.gov (United States)

Mighell, A D

2001-01-01

In theory, physical crystals can be represented by idealized mathematical lattices. Under appropriate conditions, these representations can be used for a variety of purposes such as identifying, classifying, and understanding the physical properties of materials. Critical to these applications is the ability to construct a unique representation of the lattice. The vital link that enabled this theory to be realized in practice was provided by the 1970 paper on the determination of reduced cells. This seminal paper led to a mathematical approach to lattice analysis initially based on systematic reduction procedures and the use of standard cells. Subsequently, the process evolved to a matrix approach based on group theory and linear algebra that offered a more abstract and powerful way to look at lattices and their properties. Application of the reduced cell to both database work and laboratory research at NIST was immediately successful. Currently, this cell and/or procedures based on reduction are widely and routinely used by the general scientific community: (i) for calculating standard cells for the reporting of crystalline materials, (ii) for classifying materials, (iii) in crystallographic database work (iv) in routine x-ray and neutron diffractometry, and (v) in general crystallographic research. Especially important is its use in symmetry determination and in identification. The focus herein is on the role of the reduced cell in lattice symmetry determination.

Lattice gauge theories

International Nuclear Information System (INIS)

Creutz, M.

1983-04-01

In the last few years lattice gauge theory has become the primary tool for the study of nonperturbative phenomena in gauge theories. The lattice serves as an ultraviolet cutoff, rendering the theory well defined and amenable to numerical and analytical work. Of course, as with any cutoff, at the end of a calculation one must consider the limit of vanishing lattice spacing in order to draw conclusions on the physical continuum limit theory. The lattice has the advantage over other regulators that it is not tied to the Feynman expansion. This opens the possibility of other approximation schemes than conventional perturbation theory. Thus Wilson used a high temperature expansion to demonstrate confinement in the strong coupling limit. Monte Carlo simulations have dominated the research in lattice gauge theory for the last four years, giving first principle calculations of nonperturbative parameters characterizing the continuum limit. Some of the recent results with lattice calculations are reviewed

Convection-diffusion lattice Boltzmann scheme for irregular lattices

NARCIS (Netherlands)

Sman, van der R.G.M.; Ernst, M.H.

2000-01-01

In this paper, a lattice Boltzmann (LB) scheme for convection diffusion on irregular lattices is presented, which is free of any interpolation or coarse graining step. The scheme is derived using the axioma that the velocity moments of the equilibrium distribution equal those of the

Multiscale structural characterizations of mixed U(iv)-An(iii) oxalates (An(iii) = Pu or Am) combining XAS and XRD measurements.

Science.gov (United States)

Arab-Chapelet, B; Martin, P M; Costenoble, S; Delahaye, T; Scheinost, A C; Grandjean, S; Abraham, F

2016-04-28

Mixed actinide(III,IV) oxalates of the general formula M2.2UAn(C2O4)5·nH2O (An = Pu or Am and M = H3O(+) and N2H5(+)) have been quantitatively precipitated by oxalic precipitation in nitric acid medium (yield >99%). Thorough multiscale structural characterization using XRD and XAS measurements confirmed the existence of mixed actinide oxalate solid solutions. The XANES analysis confirmed that the oxidation states of the metallic cations, tetravalent for uranium and trivalent for plutonium and americium, are maintained during the precipitation step. EXAFS measurements show that the local environments around U(+IV), Pu(+III) and Am(+III) are comparable, and the actinides are surrounded by ten oxygen atoms from five bidentate oxalate anions. The mean metal-oxygen distances obtained by XAS measurements are in agreement with those calculated from XRD lattice parameters.

Characterisation of a Compton suppressed Clover detector for high energy gamma rays (=<11MeV)

International Nuclear Information System (INIS)

Saha Sarkar, M.; Kshetri, Ritesh; Raut, Rajarshi; Mukherjee, A.; Sinha, Mandira; Ray, Maitreyi; Goswami, A.; Roy, Subinit; Basu, P.; Majumder, H.; Bhattacharya, S.; Dasmahapatra, B.

2006-01-01

Gamma ray spectra of two (p,γ) resonances have been utilised for the characterisation of the Clover detector at energies beyond 5MeV. Apart from the efficiency and the resolution of the detector, the shapes of the full energy peaks as well as the nature of the escape peaks which are also very crucial at higher energies have been analysed with special attention. Proper gain matching in software have checked deterioration in the energy resolution and distortion in the peak shape due to addback. The addback factors show sharp increasing trend even at energies around 11MeV

Characterisation of a Compton suppressed Clover detector for high energy gamma rays (=<11MeV)

Energy Technology Data Exchange (ETDEWEB)

Saha Sarkar, M. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India)]. E-mail: maitrayee.sahasarkar@saha.ac.in; Kshetri, Ritesh [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India); Raut, Rajarshi [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India); Mukherjee, A. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India); Sinha, Mandira [Gurudas College, Narkeldanga, Kolkata-700054 (India); Ray, Maitreyi [Behala College, Parnashree, Kolkata-700060 (India); Goswami, A. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India); Roy, Subinit [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India); Basu, P. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India); Majumder, H. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India); Bhattacharya, S. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India); Dasmahapatra, B. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700064 (India)

2006-01-01

Gamma ray spectra of two (p,{gamma}) resonances have been utilised for the characterisation of the Clover detector at energies beyond 5MeV. Apart from the efficiency and the resolution of the detector, the shapes of the full energy peaks as well as the nature of the escape peaks which are also very crucial at higher energies have been analysed with special attention. Proper gain matching in software have checked deterioration in the energy resolution and distortion in the peak shape due to addback. The addback factors show sharp increasing trend even at energies around 11MeV.

Phase transitions in cooperative coinfections: Simulation results for networks and lattices

Science.gov (United States)

Grassberger, Peter; Chen, Li; Ghanbarnejad, Fakhteh; Cai, Weiran

2016-04-01

We study the spreading of two mutually cooperative diseases on different network topologies, and with two microscopic realizations, both of which are stochastic versions of a susceptible-infected-removed type model studied by us recently in mean field approximation. There it had been found that cooperativity can lead to first order transitions from spreading to extinction. However, due to the rapid mixing implied by the mean field assumption, first order transitions required nonzero initial densities of sick individuals. For the stochastic model studied here the results depend strongly on the underlying network. First order transitions are found when there are few short but many long loops: (i) No first order transitions exist on trees and on 2-d lattices with local contacts. (ii) They do exist on Erdős-Rényi (ER) networks, on d -dimensional lattices with d ≥4 , and on 2-d lattices with sufficiently long-ranged contacts. (iii) On 3-d lattices with local contacts the results depend on the microscopic details of the implementation. (iv) While single infected seeds can always lead to infinite epidemics on regular lattices, on ER networks one sometimes needs finite initial densities of infected nodes. (v) In all cases the first order transitions are actually "hybrid"; i.e., they display also power law scaling usually associated with second order transitions. On regular lattices, our model can also be interpreted as the growth of an interface due to cooperative attachment of two species of particles. Critically pinned interfaces in this model seem to be in different universality classes than standard critically pinned interfaces in models with forbidden overhangs. Finally, the detailed results mentioned above hold only when both diseases propagate along the same network of links. If they use different links, results can be rather different in detail, but are similar overall.

Biochanin A (an isoflavone produced by red clover) promotes weight gain of steers grazed in mixed grass pastures and fed dried-distillers grains

Science.gov (United States)

Biochanin A (BCA) is an isoflavone produced by red clover (Trifloium pratense L.) that can inhibit hyper-ammonia producing bacteria (HAB) to reduce deamination in the rumen and increase the feed amino acids available for gastric digestion. An in vitro experiment was conducted to evaluate the effect...

Lattices with unique complements

CERN Document Server

Saliĭ, V N

1988-01-01

The class of uniquely complemented lattices properly contains all Boolean lattices. However, no explicit example of a non-Boolean lattice of this class has been found. In addition, the question of whether this class contains any complete non-Boolean lattices remains unanswered. This book focuses on these classical problems of lattice theory and the various attempts to solve them. Requiring no specialized knowledge, the book is directed at researchers and students interested in general algebra and mathematical logic.

Further Evidence for an unstable H-Dibaryon ?

International Nuclear Information System (INIS)

Wetzorke, I.; Karsch, F.; Laermann, E.

2000-01-01

We present preliminary results for the mass of the 6q flavor-singlet state (J P = 0 + , S = -2) called H-dibaryon, calculated in quenched QCD on 16 3 x30 and 243x30 lattices with improved gauge and fermion actions (Symanzik improvement, Clover action). For both lattice sizes we applied the fuzzing technique to enhance the overlap with the ground state. We observe a H-mass above the ΛΛ-threshold for strong decay. The difference in mass, mH - 2 mλ , increases with increasing lattice size

Further Evidence for an unstable H-Dibaryon ?

Energy Technology Data Exchange (ETDEWEB)

Wetzorke, I.; Karsch, F.; Laermann, E

2000-03-01

We present preliminary results for the mass of the 6q flavor-singlet state (J{sup P} = 0{sup +}, S = -2) called H-dibaryon, calculated in quenched QCD on 16{sup 3}x30 and 243x30 lattices with improved gauge and fermion actions (Symanzik improvement, Clover action). For both lattice sizes we applied the fuzzing technique to enhance the overlap with the ground state. We observe a H-mass above the {lambda}{lambda}-threshold for strong decay. The difference in mass, mH - 2{sub m{lambda}}, increases with increasing lattice size.

The Lattice-Valued Turing Machines and the Lattice-Valued Type 0 Grammars

Directory of Open Access Journals (Sweden)

Juan Tang

2014-01-01

Full Text Available Purpose. The purpose of this paper is to study a class of the natural languages called the lattice-valued phrase structure languages, which can be generated by the lattice-valued type 0 grammars and recognized by the lattice-valued Turing machines. Design/Methodology/Approach. From the characteristic of natural language, this paper puts forward a new concept of the l-valued Turing machine. It can be used to characterize recognition, natural language processing, and dynamic characteristics. Findings. The mechanisms of both the generation of grammars for the lattice-valued type 0 grammar and the dynamic transformation of the lattice-valued Turing machines were given. Originality/Value. This paper gives a new approach to study a class of natural languages by using lattice-valued logic theory.

Local non-Calderbank-Shor-Steane quantum error-correcting code on a three-dimensional lattice

International Nuclear Information System (INIS)

Kim, Isaac H.

2011-01-01

We present a family of non-Calderbank-Shor-Steane quantum error-correcting code consisting of geometrically local stabilizer generators on a 3D lattice. We study the Hamiltonian constructed from ferromagnetic interaction of overcomplete set of local stabilizer generators. The degenerate ground state of the system is characterized by a quantum error-correcting code whose number of encoded qubits are equal to the second Betti number of the manifold. These models (i) have solely local interactions; (ii) admit a strong-weak duality relation with an Ising model on a dual lattice; (iii) have topological order in the ground state, some of which survive at finite temperature; and (iv) behave as classical memory at finite temperature.

Local non-Calderbank-Shor-Steane quantum error-correcting code on a three-dimensional lattice

Science.gov (United States)

Kim, Isaac H.

2011-05-01

We present a family of non-Calderbank-Shor-Steane quantum error-correcting code consisting of geometrically local stabilizer generators on a 3D lattice. We study the Hamiltonian constructed from ferromagnetic interaction of overcomplete set of local stabilizer generators. The degenerate ground state of the system is characterized by a quantum error-correcting code whose number of encoded qubits are equal to the second Betti number of the manifold. These models (i) have solely local interactions; (ii) admit a strong-weak duality relation with an Ising model on a dual lattice; (iii) have topological order in the ground state, some of which survive at finite temperature; and (iv) behave as classical memory at finite temperature.

Additive lattice kirigami.

Science.gov (United States)

Castle, Toen; Sussman, Daniel M; Tanis, Michael; Kamien, Randall D

2016-09-01

Kirigami uses bending, folding, cutting, and pasting to create complex three-dimensional (3D) structures from a flat sheet. In the case of lattice kirigami, this cutting and rejoining introduces defects into an underlying 2D lattice in the form of points of nonzero Gaussian curvature. A set of simple rules was previously used to generate a wide variety of stepped structures; we now pare back these rules to their minimum. This allows us to describe a set of techniques that unify a wide variety of cut-and-paste actions under the rubric of lattice kirigami, including adding new material and rejoining material across arbitrary cuts in the sheet. We also explore the use of more complex lattices and the different structures that consequently arise. Regardless of the choice of lattice, creating complex structures may require multiple overlapping kirigami cuts, where subsequent cuts are not performed on a locally flat lattice. Our additive kirigami method describes such cuts, providing a simple methodology and a set of techniques to build a huge variety of complex 3D shapes.

The effects of PPO activity on the proteome of ingested red clover and implications for improving the nutrition of grazing cattle.

Science.gov (United States)

Hart, E H; Onime, L A; Davies, T E; Morphew, R M; Kingston-Smith, A H

2016-06-01

Increasing the rumen-stable protein content of feed would lead to improved nitrogen utilisation in cattle, and less nitrogenous waste. Red clover (Trifolium pratense L.) is a high protein ruminant feed containing high polyphenol oxidase (PPO) activity. PPO mediated protein-quinone binding has been linked to protecting plant proteins from proteolysis. To explore the mechanism underlying the effect of PPO on protein protection in fresh forage feeds, proteomic components of feed down-boli produced from wild-type red clover and a low PPO mutant, at point of ingestion and after 4h in vitro incubation with rumen inoculum were analysed. Significant differences in proteomic profiles between wild-type and mutant red clover were determined after 4h incubation, with over 50% less spots in mutant than wild-type proteomes, indicating decreased proteolysis in the latter. Protein identifications revealed preferentially retained proteins localised within the chloroplast, suggesting that PPO mediated protection in the wild-type operates due to the proximity of target proteins to the enzyme and substrates, either diffusing into this compartment from the vacuole or are present in the chloroplast. This increased understanding of protein targets of PPO indicates that wider exploitation of the trait could contribute to increased protein use efficiency in grazing cattle. One of the main challenges for sustainable livestock farming is improving capture of dietary nitrogen by ruminants. Typically up to 70% of ingested protein-N is excreted representing a loss of productivity potential and a serious environmental problem in terms of nitrogenous pollution of lands and water. Identification of key characteristics of rumen-protected protein will deliver target traits for selection in forage breeding programmes. The chloroplastic enzyme PPO catalyzes the oxidation of phenols to quinones, which react with protein. Little is currently known about the intracellular protein targets of the products

Nitrous oxide emissions from clover in the Mediterranean environment

Directory of Open Access Journals (Sweden)

Iride Volpi

2016-06-01

Full Text Available Introducing nitrogen N2-fixing crops into cereal-based crop rotations reduces N-fertiliser use and may mitigate soil emissions of nitrous oxide (N2O. However, the effect of the cultivation of N2-fixing crops on N2O emissions is still not well understood. N2O from N2-fixing crops can be emitted in two ways: during biological N2 fixation itself and when legume residues are returned to the soil. A field trial was carried out on clover (Trifolium squarrosum Savi to test the role of leguminous crops on N2O emissions in the Mediterranean environment. Monitoring was performed from December 2013 to September 2014. Cumulated N-N2O fluxes were calculated for the growing season (Phase 1 and the post-harvest period (Phase 2 in order to assess the importance of each phase. Our results did not show statistically significant differences between the two phases in term of contribution to the total cumulative N-N2O emissions, in fact Phase 1 and Phase 2 accounted respectively for 43 and 57% of the total.

Finite-lattice-spacing corrections to masses and g factors on a lattice

International Nuclear Information System (INIS)

Roskies, R.; Wu, J.C.

1986-01-01

We suggest an alternative method for extracting masses and g factors from lattice calculations. Our method takes account of more of the infrared and ultraviolet lattice effects. It leads to more reasonable results in simulations of QED on a lattice

Lattices for laymen: a non-specialist's introduction to lattice gauge theory

International Nuclear Information System (INIS)

Callaway, D.J.E.

1985-01-01

The review on lattice gauge theory is based upon a series of lectures given to the Materials Science and Technology Division at Argonne National Laboratory. Firstly the structure of gauge theories in the continuum is discussed. Then the lattice formulation of these theories is presented, including quantum electrodynamics and non-abelian lattice gauge theories. (U.K.)

Lattice QCD on fine lattices

Energy Technology Data Exchange (ETDEWEB)

Schaefer, Stefan [DESY (Germany). Neumann Inst. for Computing

2016-11-01

These configurations are currently in use in many on-going projects carried out by researchers throughout Europe. In particular this data will serve as an essential input into the computation of the coupling constant of QCD, where some of the simulations are still on-going. But also projects computing the masses of hadrons and investigating their structure are underway as well as activities in the physics of heavy quarks. As this initial project of gauge field generation has been successful, it is worthwhile to extend the currently available ensembles with further points in parameter space. These will allow to further study and control systematic effects like the ones introduced by the finite volume, the non-physical quark masses and the finite lattice spacing. In particular certain compromises have still been made in the region where pion masses and lattice spacing are both small. This is because physical pion masses require larger lattices to keep the effects of the finite volume under control. At light pion masses, a precise control of the continuum extrapolation is therefore difficult, but certainly a main goal of future simulations. To reach this goal, algorithmic developments as well as faster hardware will be needed.

Instanton dominance of topological charge fluctuations in QCD?

International Nuclear Information System (INIS)

Hip, I.; Lippert, Th.; Schilling, K.; Schroers, W.; Neff, H.

2002-01-01

We consider the local chirality of near-zero eigenvectors from Wilson-Dirac and clover improved Wilson-Dirac lattice operators as proposed recently by Horvath et al. We study finer lattices and repair for the loss of orthogonality due to the non-normality of the Wilson-Dirac matrix. As a result we do see a clear double peak structure on lattices with resolutions higher than 0.1 fm. We find that the lattice artifacts can be considerably reduced by exploiting the biorthogonal system of left and right eigenvectors. We conclude that the dominance of instantons in topological charge fluctuations is not ruled out by local chirality measurements

Response of irradiated Egyptian clover (Trifolium alexandrinum L.) to water stress

International Nuclear Information System (INIS)

Hamideldin, N; Hussein, O.S

2009-01-01

Egyptian clover (Trifolium alexandrinum L.) is one of the main leguminous forage crops in Egypt. Gamma rays represent one of the important physical activators for growth and productivity. The seed were irradiated using three doses of gamma radiation (100,200 and 300 Gy) and two levels of irrigation (10 and 20 days) after germination. Gamma radiation treatments stimulated growth criteria in normal irrigation treatment, while drought irrigation treatment stunted these criteria. The most significant dose was 100 Gy, which stimulated growth criteria, chlorophylls a , b, total chlorophyll and carotenoids in both irrigation treatments used and growth hormones under drought condition. Drought stress and gamma irradiation increase amino acid content and caused change in band concentration of esterase and peroxidase isozyme .Also, 13 protein bands appeared only in treated plant with 100 Gy under drought condition. It could be concluded that the low dose (100 Gy) of gamma irradiation release the effect of drought stress.

Disconnected quark loop contributions to nucleon observables using Nf=2 twisted clover fermions at the physical value of the light quark mass

International Nuclear Information System (INIS)

Abdel-Rehim, Abdou; Kallidonis, Christos; Koutsou, Giannis

2015-11-01

We compute the disconnected quark loops contributions entering the determination of nucleon observables, by using a N f =2 ensemble of twisted mass fermions with a clover term at a pion mass m π =133 MeV. We employ exact deflation and implement all calculations in GPUs, enabling us to achieve large statistics and a good signal.

On singularities of lattice varieties

OpenAIRE

Mukherjee, Himadri

2013-01-01

Toric varieties associated with distributive lattices arise as a fibre of a flat degeneration of a Schubert variety in a minuscule. The singular locus of these varieties has been studied by various authors. In this article we prove that the number of diamonds incident on a lattice point $\\a$ in a product of chain lattices is more than or equal to the codimension of the lattice. Using this we also show that the lattice varieties associated with product of chain lattices is smooth.

Irradiation-induced displacement of Ag atoms from lattice sites in an Al-0.2% Mg-0.1% Ag crystal

International Nuclear Information System (INIS)

Swanson, M.L.; Howe, L.M.; Quenneville, A.F.

1976-01-01

In irradiated alloys of Al containing approximately 0.1 at% Ag, the backscattering - channelling method shows that Al-Ag dumbells are created by the trapping of Al interstitial atoms at Ag solute atoms. The present results demonstrate that the addition of 0.2 at% Mg to such irradiated alloys retards not only the formation of Al-Ag dumbells during annealing from 30 to 100 K but also their annihilation during annealing from 180 to 240 K. Al interstitials are released from Mg traps at 100 to 160 K, causing further trapping at Ag atoms. Approximately 70% of the Ag atoms return to lattice sites at approximately 200 K (stage III) (compared with 100% in the Al-0.1% Ag alloys) and the remainder return to lattice sites at approximately 260 K. These results favour migration of Al-Ag dumbells rather than vacancies during stage III annealing. (author)

Crystal structures of fac-trichloridotris(trimethylphosphane-κPrhodium(III monohydrate and fac-trichloridotris(trimethylphosphane-κPrhodium(III methanol hemisolvate: rhodium structures that are isotypic with their iridium analogs

Directory of Open Access Journals (Sweden)

Joseph S. Merola

2015-02-01

Full Text Available The crystal structures of two solvates of fac-trichloridotris(trimethylphosphane-κPrhodium(III are reported, i.e. one with water in the crystal lattice, fac-[RhCl3(Me3P3]·H2O, and one with methanol in the crystal lattice, fac-[RhCl3(Me3P3]·0.5CH3OH. These rhodium compounds exhibit distorted octahedral coordination spheres at the metal and are isotypic with the analogous iridium compounds previously reported by us [Merola et al. (2013. Polyhedron, 54, 67–73]. Comparison is made between the rhodium and iridium compounds, highlighting their isostructural relationships.

Ozone and Water Stress: Effects on the Behaviour of Two White Clover Biotypes

Directory of Open Access Journals (Sweden)

Massimo Fagnano

Full Text Available ozone pollution, water stress, stomata conductance, ozone uptake, clover, OTC.Ozone is a strong oxidizing pollutant which derives by alteration of the photolytic NOx cycle and it accumulates in the troposphere spreading in rural areas and therefore determining injuries on natural vegetation and crops. Since its penetration occurs mainly through stomata, all factors which alter plant-atmosphere relations could be able to modify plant response to ozone. Interaction between ozone and water stress in Mediterranean environment was studied on ozone resistant and sensitive biotypes of white clover, which were grown in charcoal filtered and notfiltered Open Top Chambers in factorial combination with different levels of water supply. Measurements of biomass, leaf area and stomatal conductance were made during the growth period. Ozone injuries were estimated as not-filtered/filtered OTC yield ratio; the stomatal flux of ozone was estimated multiplying stomata conductance x diffusivity ratio between ozone and water vapour (0.613 x ozone hourly concentrations. The hourly values of ozone uptake were cumulated throughout the cropping periods of the two years. In the sensitive biotype, water stress reduced yield losses due to ozone from 38% to 22%, as well as yield losses due to water stress were reduced by the presence of ozone from 43% to 29%, while no interaction between ozone and water stress was observed in the resistant biotype. Biomass yield losses of the sensitive biotype were strictly correlated to cumulated ozone uptake (R2 = 0.99, while biomass yield losses of the resistant biotype were not affected by the ozone fluxes variations created by the treatments. Flux based models could better estimate yield losses due to ozone in Mediterranean environments in which other stresses could be contemporary present; therefore, the new European directives might replace the actual thresholds based

Progress in simulations with twisted mass fermions at the physical point

International Nuclear Information System (INIS)

Abdel-Rehim, A.

2014-11-01

In this contribution, results from N f =2 lattice QCD simulations at one lattice spacing using twisted mass fermions with a clover term at the physical pion mass are presented. The mass splitting between charged and neutral pions (including the disconnected contribution) is shown to be around 20(20) MeV. Further, a first measurement using the clover twisted mass action of the average momentum fraction of the pion is given. Finally, an analysis of pseudoscalar meson masses and decay constants is presented involving linear interpolations in strange and charm quark masses. Matching to meson mass ratios allows the calculation of quark mass ratios: μ s /μ l =27.63(13), μ c /μ l =339.6(2.2) and μ c /μ s =12.29(10). From this mass matching the quantities f K =153.9(7.5) MeV, f D =219(11) MeV, f D s =255(12) MeV and M D s =1894(93) MeV are determined without the application of finite volume or discretization artefact corrections and with errors dominated by a preliminary estimate of the lattice spacing.

Design and fabrication of 4π Clover Detector Array Assembly for gamma-spectroscopy studies using thermal neutrons

International Nuclear Information System (INIS)

Kumar, Manish; Kamble, S.R.; Chaudhari, A.T.; Sabharwal, T.P.; Pathak, Kavindra; Prasad, N.K.; Kinage, L.A.; Biswas, D.C.; Bhagwat, P.V.

2017-01-01

Nuclear spectroscopy has been studied earlier from the measurement of prompt gamma rays produced in reactions with thermal neutrons from CIRUS reactor. For studying the prompt γ-spectroscopy using thermal neutrons from Dhruva Reactor, BARC, the development of a dedicated beam line (R-3001) is in progress. In this beam line a detector assembly consisting of Clover Ge detectors will be used. This experimental setup will be utilized to investigate nuclear structure using prompt (n,γ) reactions and also to study the spectroscopy of neutron-rich fission-fragment nuclei

The combined effect of fertiliser nitrogen and phosphorus on herbage yield and change in soil nutrients of a grass/clover and grass-only sward

NARCIS (Netherlands)

Schils, R.L.M.; Snijders, P.J.M.

2004-01-01

The combined effect of reduced nitrogen ( N ) and phosphorus ( P ) application on the production of grass- only and grass/ clover swards was studied in a five- year cutting experiment on a marine clay soil, established on newly sown swards. Furthermore, changes in soil N, P and carbon ( C ) were

Reactor lattice codes

International Nuclear Information System (INIS)

Kulikowska, T.

2001-01-01

The description of reactor lattice codes is carried out on the example of the WIMSD-5B code. The WIMS code in its various version is the most recognised lattice code. It is used in all parts of the world for calculations of research and power reactors. The version WIMSD-5B is distributed free of charge by NEA Data Bank. The description of its main features given in the present lecture follows the aspects defined previously for lattice calculations in the lecture on Reactor Lattice Transport Calculations. The spatial models are described, and the approach to the energy treatment is given. Finally the specific algorithm applied in fuel depletion calculations is outlined. (author)

Lattice topology dictates photon statistics.

Science.gov (United States)

Kondakci, H Esat; Abouraddy, Ayman F; Saleh, Bahaa E A

2017-08-21

Propagation of coherent light through a disordered network is accompanied by randomization and possible conversion into thermal light. Here, we show that network topology plays a decisive role in determining the statistics of the emerging field if the underlying lattice is endowed with chiral symmetry. In such lattices, eigenmode pairs come in skew-symmetric pairs with oppositely signed eigenvalues. By examining one-dimensional arrays of randomly coupled waveguides arranged on linear and ring topologies, we are led to a remarkable prediction: the field circularity and the photon statistics in ring lattices are dictated by its parity while the same quantities are insensitive to the parity of a linear lattice. For a ring lattice, adding or subtracting a single lattice site can switch the photon statistics from super-thermal to sub-thermal, or vice versa. This behavior is understood by examining the real and imaginary fields on a lattice exhibiting chiral symmetry, which form two strands that interleave along the lattice sites. These strands can be fully braided around an even-sited ring lattice thereby producing super-thermal photon statistics, while an odd-sited lattice is incommensurate with such an arrangement and the statistics become sub-thermal.

Void lattices

International Nuclear Information System (INIS)

Chadderton, L.T.; Johnson, E.; Wohlenberg, T.

1976-01-01

Void lattices in metals apparently owe their stability to elastically anisotropic interactions. An ordered array of voids on the anion sublattice in fluorite does not fit so neatly into this scheme of things. Crowdions may play a part in the formation of the void lattice, and stability may derive from other sources. (Auth.)

Lattice theory for nonspecialists

International Nuclear Information System (INIS)

Hari Dass, N.D.

1984-01-01

These lectures were delivered as part of the academic training programme at the NIKHEF-H. These lectures were intended primarily for experimentalists, and theorists not specializing in lattice methods. The goal was to present the essential spirit behind the lattice approach and consequently the author has concentrated mostly on issues of principle rather than on presenting a large amount of detail. In particular, the author emphasizes the deep theoretical infra-structure that has made lattice studies meaningful. At the same time, he has avoided the use of heavy formalisms as they tend to obscure the basic issues for people trying to approach this subject for the first time. The essential ideas are illustrated with elementary soluble examples not involving complicated mathematics. The following subjects are discussed: three ways of solving the harmonic oscillator problem; latticization; gauge fields on a lattice; QCD observables; how to solve lattice theories. (Auth.)

Comparison of buckwheat, red clover, and purple tansy as potential surrogate plants for use in semi-field pesticide risk assessments with Bombus impatiens

Directory of Open Access Journals (Sweden)

Angela E. Gradish

2016-07-01

Full Text Available Background. Bumble bees (Bombus spp. are important wild and managed pollinators. There is increased interest in incorporating data on bumble bees into risk assessments for pesticides, but standardized methods for assessing hazards of pesticides in semi-field and field settings have not yet been established for bumble bees. During semi-field studies, colonies are caged with pesticide-treated flowering surrogate plants, which must be attractive to foragers to ensure colony exposure to the test compound, and must produce an ample nectar and pollen to sustain colonies during testing. However, it is not known which plant(s are suitable for use in semi-field studies with bumble bees. Materials and Methods. We compared B. impatiens foraging activity and colony development on small plots of flowering buckwheat (Fagopyrum esculentum, var. common, red clover (Trifolium pratense, and purple tansy (Phacelia tanacetifolia under semi-field conditions to assess their suitability as surrogate plants for pesticide risk assessment studies with bumble bees. We also compared the growth characteristics and input requirements of each plant type. Results. All three plant types generally established and grew well. Red clover and purple tansy experienced significant weed pressure and/or insect pest damage. In contrast, pest pressure was extremely low in buckwheat. Overall, B. impatiens foraging activity was significantly greater on buckwheat plots than red clover or purple tansy, but plant type had no effect on number of individuals produced per colony or colony weight. Discussion. Because of the consistently high foraging activity and successful colony development observed on buckwheat plots, combined with its favourable growth characteristics and low maintenance requirements, we recommend buckwheat as a surrogate plant for use in semi-field pesticide toxicity assessments with B. impatiens.

Forage Quantity and Quality of Berseem Clover (Trifolium ‎alexandrinum L. as Affected by Uses of Pseudomonas putida ‎Strains and Phophorus Fertilizer in the Second Crop

Directory of Open Access Journals (Sweden)

Mohammad Hossein Ansari

2017-05-01

Full Text Available Effects of phosphate fertilizer and pseudomonas putida strains on the quantity and quality of forage of berseem clover as a second crop was studied in a factorial field experiment using randomized complete block design with three replications at Fooman, Guilan province, Iran. Treatments consisted of phosphate fertilizer with three levels (0, 75 and 150 kg/ha as triple super phosphate and Pseudomonas putida strains with four levels (M21, M5, M168 and control. The results showed that use of phosphate fertilizers increased the soil pH during growing season while bacterial inoculation adjusted soil pH. The bacterial inoculation increased amount of crude protein, digestible protein, acidic and alkaline phosphatase activity compared to non-inoculated treatment, but it decreased crude fiber of the forage. Clover forage yield, protein yield and phosphorus content of foliage also were influenced by the interaction of bacterial strains and phosphate fertilizer. The highest forage and protein yield were obtained by using strain M5+150 kg P ha-1. Significant increases in forage and protein yield were found to be 16.49% and 8.01%, respectively, as compared with non-inoculated treatment. Based on the result of this experiment, application of 150 kg P ha-1 and Pseudomonas putida strain M5 inoculation can be used to obtain highest forage yield and quality of berseem clover as second crop in the experimental site.

The effect of additives in silages of pure timothy and timothy mixed with red clover on chemical composition and in vitro rumen fermentation characteristics

NARCIS (Netherlands)

Hetta, M.; Cone, J.W.; Gustavsson, A.M.; Martinsson, K.

2003-01-01

The aim was to compare the effects of additives on direct cut silages of pure timothy and timothy mixed with tetraploid red clover. First and second growth cuts were ensiled during three consecutive years, 1994, 1995 and 1996, either without any additive or with the addition of formic acid, or

MEETING: Lattice 88

Energy Technology Data Exchange (ETDEWEB)

Mackenzie, Paul

1989-03-15

The forty-year dream of understanding the properties of the strongly interacting particles from first principles is now approaching reality. Quantum chromodynamics (QCD - the field theory of the quark and gluon constituents of strongly interacting particles) was initially handicapped by the severe limitations of the conventional (perturbation) approach in this picture, but Ken Wilson's inventions of lattice gauge theory and renormalization group methods opened new doors, making calculations of masses and other particle properties possible. Lattice gauge theory became a major industry around 1980, when Monte Carlo methods were introduced, and the first prototype calculations yielded qualitatively reasonable results. The promising developments over the past year were highlighted at the 1988 Symposium on Lattice Field Theory - Lattice 88 - held at Fermilab.

MEETING: Lattice 88

International Nuclear Information System (INIS)

Mackenzie, Paul

1989-01-01

The forty-year dream of understanding the properties of the strongly interacting particles from first principles is now approaching reality. Quantum chromodynamics (QCD - the field theory of the quark and gluon constituents of strongly interacting particles) was initially handicapped by the severe limitations of the conventional (perturbation) approach in this picture, but Ken Wilson's inventions of lattice gauge theory and renormalization group methods opened new doors, making calculations of masses and other particle properties possible. Lattice gauge theory became a major industry around 1980, when Monte Carlo methods were introduced, and the first prototype calculations yielded qualitatively reasonable results. The promising developments over the past year were highlighted at the 1988 Symposium on Lattice Field Theory - Lattice 88 - held at Fermilab

Twisted mass lattice QCD

International Nuclear Information System (INIS)

Shindler, A.

2007-07-01

I review the theoretical foundations, properties as well as the simulation results obtained so far of a variant of the Wilson lattice QCD formulation: Wilson twisted mass lattice QCD. Emphasis is put on the discretization errors and on the effects of these discretization errors on the phase structure for Wilson-like fermions in the chiral limit. The possibility to use in lattice simulations different lattice actions for sea and valence quarks to ease the renormalization patterns of phenomenologically relevant local operators, is also discussed. (orig.)

Twisted mass lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Shindler, A. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

2007-07-15

I review the theoretical foundations, properties as well as the simulation results obtained so far of a variant of the Wilson lattice QCD formulation: Wilson twisted mass lattice QCD. Emphasis is put on the discretization errors and on the effects of these discretization errors on the phase structure for Wilson-like fermions in the chiral limit. The possibility to use in lattice simulations different lattice actions for sea and valence quarks to ease the renormalization patterns of phenomenologically relevant local operators, is also discussed. (orig.)

Current quantization and fractal hierarchy in a driven repulsive lattice gas.

Science.gov (United States)

Rotondo, Pietro; Sellerio, Alessandro Luigi; Glorioso, Pietro; Caracciolo, Sergio; Cosentino Lagomarsino, Marco; Gherardi, Marco

2017-11-01

Driven lattice gases are widely regarded as the paradigm of collective phenomena out of equilibrium. While such models are usually studied with nearest-neighbor interactions, many empirical driven systems are dominated by slowly decaying interactions such as dipole-dipole and Van der Waals forces. Motivated by this gap, we study the nonequilibrium stationary state of a driven lattice gas with slow-decayed repulsive interactions at zero temperature. By numerical and analytical calculations of the particle current as a function of the density and of the driving field, we identify (i) an abrupt breakdown transition between insulating and conducting states, (ii) current quantization into discrete phases where a finite current flows with infinite differential resistivity, and (iii) a fractal hierarchy of excitations, related to the Farey sequences of number theory. We argue that the origin of these effects is the competition between scales, which also causes the counterintuitive phenomenon that crystalline states can melt by increasing the density.

Current quantization and fractal hierarchy in a driven repulsive lattice gas

Science.gov (United States)

Rotondo, Pietro; Sellerio, Alessandro Luigi; Glorioso, Pietro; Caracciolo, Sergio; Cosentino Lagomarsino, Marco; Gherardi, Marco

2017-11-01

Driven lattice gases are widely regarded as the paradigm of collective phenomena out of equilibrium. While such models are usually studied with nearest-neighbor interactions, many empirical driven systems are dominated by slowly decaying interactions such as dipole-dipole and Van der Waals forces. Motivated by this gap, we study the nonequilibrium stationary state of a driven lattice gas with slow-decayed repulsive interactions at zero temperature. By numerical and analytical calculations of the particle current as a function of the density and of the driving field, we identify (i) an abrupt breakdown transition between insulating and conducting states, (ii) current quantization into discrete phases where a finite current flows with infinite differential resistivity, and (iii) a fractal hierarchy of excitations, related to the Farey sequences of number theory. We argue that the origin of these effects is the competition between scales, which also causes the counterintuitive phenomenon that crystalline states can melt by increasing the density.

Lattice regularized chiral perturbation theory

International Nuclear Information System (INIS)

Borasoy, Bugra; Lewis, Randy; Ouimet, Pierre-Philippe A.

2004-01-01

Chiral perturbation theory can be defined and regularized on a spacetime lattice. A few motivations are discussed here, and an explicit lattice Lagrangian is reviewed. A particular aspect of the connection between lattice chiral perturbation theory and lattice QCD is explored through a study of the Wess-Zumino-Witten term

Supersymmetric lattices

International Nuclear Information System (INIS)

Catterall, Simon

2013-01-01

Discretization of supersymmetric theories is an old problem in lattice field theory. It has resisted solution until quite recently when new ideas drawn from orbifold constructions and topological field theory have been brought to bear on the question. The result has been the creation of a new class of lattice gauge theory in which the lattice action is invariant under one or more supersymmetries. The resultant theories are local and free of doublers and in the case of Yang-Mills theories also possess exact gauge invariance. In principle they form the basis for a truly non-perturbative definition of the continuum supersymmetric field theory. In this talk these ideas are reviewed with particular emphasis being placed on N = 4 super Yang-Mills theory.

Vortex lattices in layered superconductors

International Nuclear Information System (INIS)

Prokic, V.; Davidovic, D.; Dobrosavljevic-Grujic, L.

1995-01-01

We study vortex lattices in a superconductor--normal-metal superlattice in a parallel magnetic field. Distorted lattices, resulting from the shear deformations along the layers, are found to be unstable. Under field variation, nonequilibrium configurations undergo an infinite sequence of continuous transitions, typical for soft lattices. The equilibrium vortex arrangement is always a lattice of isocell triangles, without shear

Mixed-valent perovskites of the type Ba/sub 3/Bsup(III)PtRuO/sub 9/

Energy Technology Data Exchange (ETDEWEB)

Kemmler-Sack, S; Ehmann, A; Herrmann, M [Tuebingen Univ. (Germany, F.R.). Lehrstuhl fuer Anorganische Chemie 2

1981-08-01

Compounds of type Ba/sub 3/Bsup(III)PtRuO/sub 9/ - with a mean oxydation state of the noble metals of +4.5 - crystallize with Bsup(III) = Gd-Lu, Y in a variant of hexagonal BaTiO/sub 3/ type with ordered cationic distribution. Intensity calculations on powder data of Ba/sub 3/YPtRuO/sub 9/ (a = 5.88/sub 8/; c = 14.7/sub 0/ A) gave in the space group P6/sub 3//mmc (sequence (hcc)/sub 2/) a refined, intensity related R' value of 5.9%. With Bsup(III) = Eu the lattice is monoclinic and for Bsup(III) = Sm, Nd, La triclinic distorted.

Development of III-Sb metamorphic DBR membranes on InP for vertical cavity laser applications

Science.gov (United States)

Addamane, S. J.; Mansoori, A.; Renteria, E. J.; Dawson, N.; Shima, D. M.; Rotter, T. J.; Hains, C. P.; Dawson, L. R.; Balakrishnan, G.

2016-04-01

Sb-based metamorphic DBR membranes are developed for InP-based vertical cavity laser applications. The reflectivity of the metamorphic DBR membrane is compared to the reflectivity of a lattice-matched DBR to characterize the optical quality of the DBR membrane. The metamorphic interface between InP and the III-antimonides is found to degrade the reflectivity of the DBR. Therefore, the growth temperature for the metamorphic DBR is optimized in order to obtain highly reflective (>99.8%) III-Sb thin-film membranes.

Short-term effects of a dung pat on N₂ fixation and total N uptake in a perennial ryegrass/white clover mixture

DEFF Research Database (Denmark)

Jørgensen, F.V.; Jensen, E.S.

1997-01-01

The short-term effects of a simulated cattle dung pat on N-2 fixation and total uptake of N in a perennial ryegrass/white clover mixture was studied in a container experiment using sheep faeces mixed with water to a DM content of 13%. We used a new N-15 cross-labelling technique to determine...

Reactor lattice codes

International Nuclear Information System (INIS)

Kulikowska, T.

1999-01-01

The present lecture has a main goal to show how the transport lattice calculations are realised in a standard computer code. This is illustrated on the example of the WIMSD code, belonging to the most popular tools for reactor calculations. Most of the approaches discussed here can be easily modified to any other lattice code. The description of the code assumes the basic knowledge of reactor lattice, on the level given in the lecture on 'Reactor lattice transport calculations'. For more advanced explanation of the WIMSD code the reader is directed to the detailed descriptions of the code cited in References. The discussion of the methods and models included in the code is followed by the generally used homogenisation procedure and several numerical examples of discrepancies in calculated multiplication factors based on different sources of library data. (author)

Kunitz Proteinase Inhibitors Limit Water Stress Responses in White Clover (Trifolium repens L.) Plants.

Science.gov (United States)

Islam, Afsana; Leung, Susanna; Nikmatullah, Aluh; Dijkwel, Paul P; McManus, Michael T

2017-01-01

The response of plants to water deficiency or drought is a complex process, the perception of which is triggered at the molecular level before any visible morphological responses are detected. It was found that different groups of plant proteinase inhibitors (PIs) are induced and play an active role during abiotic stress conditions such as drought. Our previous work with the white clover ( Trifolium repens L.) Kunitz Proteinase Inhibitor ( Tr-KPI ) gene family showed that Tr-KPIs are differentially regulated to ontogenetic and biotic stress associated cues and that, at least some members of this gene family may be required to maintain cellular homeostasis. Altered cellular homeostasis may also affect abiotic stress responses and therefore, we aimed to understand if distinct Tr-PKI members function during drought stress. First, the expression level of three Tr-KPI genes, Tr-KPI1 , Tr-KPI2 , and Tr-KPI5 , was measured in two cultivars and one white clover ecotype with differing capacity to tolerate drought. The expression of Tr-KPI1 and Tr-KPI5 increased in response to water deficiency and this was exaggerated when the plants were treated with a previous period of water deficiency. In contrast, proline accumulation and increased expression of Tr-NCED1 , a gene encoding a protein involved in ABA biosynthesis, was delayed in plants that experienced a previous drought period. RNAi knock-down of Tr-KPI1 and Tr-KPI5 resulted in increased proline accumulation in leaf tissue of plants grown under both well-watered and water-deficit conditions. In addition, increased expression of genes involved in ethylene biosynthesis was found. The data suggests that Tr-KPIs , particularly Tr-KPI5 , have an explicit function during water limitation. The results also imply that the Tr-KPI family has different in planta proteinase targets and that the functions of this protein family are not solely restricted to one of storage proteins or in response to biotic stress.

Kunitz Proteinase Inhibitors Limit Water Stress Responses in White Clover (Trifolium repens L. Plants

Directory of Open Access Journals (Sweden)

Afsana Islam

2017-10-01

Full Text Available The response of plants to water deficiency or drought is a complex process, the perception of which is triggered at the molecular level before any visible morphological responses are detected. It was found that different groups of plant proteinase inhibitors (PIs are induced and play an active role during abiotic stress conditions such as drought. Our previous work with the white clover (Trifolium repens L. Kunitz Proteinase Inhibitor (Tr-KPI gene family showed that Tr-KPIs are differentially regulated to ontogenetic and biotic stress associated cues and that, at least some members of this gene family may be required to maintain cellular homeostasis. Altered cellular homeostasis may also affect abiotic stress responses and therefore, we aimed to understand if distinct Tr-PKI members function during drought stress. First, the expression level of three Tr-KPI genes, Tr-KPI1, Tr-KPI2, and Tr-KPI5, was measured in two cultivars and one white clover ecotype with differing capacity to tolerate drought. The expression of Tr-KPI1 and Tr-KPI5 increased in response to water deficiency and this was exaggerated when the plants were treated with a previous period of water deficiency. In contrast, proline accumulation and increased expression of Tr-NCED1, a gene encoding a protein involved in ABA biosynthesis, was delayed in plants that experienced a previous drought period. RNAi knock-down of Tr-KPI1 and Tr-KPI5 resulted in increased proline accumulation in leaf tissue of plants grown under both well-watered and water-deficit conditions. In addition, increased expression of genes involved in ethylene biosynthesis was found. The data suggests that Tr-KPIs, particularly Tr-KPI5, have an explicit function during water limitation. The results also imply that the Tr-KPI family has different in planta proteinase targets and that the functions of this protein family are not solely restricted to one of storage proteins or in response to biotic stress.

Toward lattice fractional vector calculus

International Nuclear Information System (INIS)

Tarasov, Vasily E

2014-01-01

An analog of fractional vector calculus for physical lattice models is suggested. We use an approach based on the models of three-dimensional lattices with long-range inter-particle interactions. The lattice analogs of fractional partial derivatives are represented by kernels of lattice long-range interactions, where the Fourier series transformations of these kernels have a power-law form with respect to wave vector components. In the continuum limit, these lattice partial derivatives give derivatives of non-integer order with respect to coordinates. In the three-dimensional description of the non-local continuum, the fractional differential operators have the form of fractional partial derivatives of the Riesz type. As examples of the applications of the suggested lattice fractional vector calculus, we give lattice models with long-range interactions for the fractional Maxwell equations of non-local continuous media and for the fractional generalization of the Mindlin and Aifantis continuum models of gradient elasticity. (papers)

Toward lattice fractional vector calculus

Science.gov (United States)

Tarasov, Vasily E.

2014-09-01

An analog of fractional vector calculus for physical lattice models is suggested. We use an approach based on the models of three-dimensional lattices with long-range inter-particle interactions. The lattice analogs of fractional partial derivatives are represented by kernels of lattice long-range interactions, where the Fourier series transformations of these kernels have a power-law form with respect to wave vector components. In the continuum limit, these lattice partial derivatives give derivatives of non-integer order with respect to coordinates. In the three-dimensional description of the non-local continuum, the fractional differential operators have the form of fractional partial derivatives of the Riesz type. As examples of the applications of the suggested lattice fractional vector calculus, we give lattice models with long-range interactions for the fractional Maxwell equations of non-local continuous media and for the fractional generalization of the Mindlin and Aifantis continuum models of gradient elasticity.

Lattice gas cellular automata and lattice Boltzmann models an introduction

CERN Document Server

Wolf-Gladrow, Dieter A

2000-01-01

Lattice-gas cellular automata (LGCA) and lattice Boltzmann models (LBM) are relatively new and promising methods for the numerical solution of nonlinear partial differential equations. The book provides an introduction for graduate students and researchers. Working knowledge of calculus is required and experience in PDEs and fluid dynamics is recommended. Some peculiarities of cellular automata are outlined in Chapter 2. The properties of various LGCA and special coding techniques are discussed in Chapter 3. Concepts from statistical mechanics (Chapter 4) provide the necessary theoretical background for LGCA and LBM. The properties of lattice Boltzmann models and a method for their construction are presented in Chapter 5.

Anomalous microstructural changes in III-nitrides under ion bombardment

International Nuclear Information System (INIS)

Kucheyev, S.O.; Williams, J.S.; Jagadish, C.

2002-01-01

Full text: Group-III nitrides (GaN, AlGaN, and InGaN) are currently a 'hot topic' in the physics and material research community due to very important technological applications of these materials in (opto)electronics. In the fabrication of III-nitride-based devices, ion bombardment represents a very attractive processing tool. However, ion-beam-produced lattice disorder and its undesirable consequences limit technological applications of ion implantation. Hence, studies of ion-beam-damage processes in Ill-nitrides are not only physically interesting but also technologically important. In this study, wurtzite GaN, AlGaN, and InGaN films exposed to ion bombardment under a wide range of irradiation conditions are studied by a combination of transmission electron microscopy (TEM), environmental scanning electron microscopy (ESEM), energy dispersive x-ray spectrometry (EDS), atomic force microscopy (AFM), cathodoluminescence (CL), and Rutherford backscattering/channeling (RBS/C) spectrometry. Results show that, unlike the situation for mature semiconductors such as Si and GaAs, Ill-nitrides exhibit a range of intriguing behavior involving extreme microstructural changes under ion bombardment. In this presentation, the following aspects are discussed: (i) formation of lattice defects during ion bombardment, (ii) ion-beam-induced phase transformations, (iii) ion-beam-produced stoichiometric imbalance and associated material decomposition, and (iv) an application of charging phenomena during ESEM imaging for studies of electrical isolation in GaN by MeV light ion irradiation. Emphasis is given to the (powerful) application of electron microscopy techniques for the understanding of physical processes occurring in Ill-nitrides under ion bombardment. Copyright (2002) Australian Society for Electron Microscopy Inc

Disconnected quark loop contributions to nucleon observables using N{sub f}=2 twisted clover fermions at the physical value of the light quark mass

Energy Technology Data Exchange (ETDEWEB)

Abdel-Rehim, Abdou; Kallidonis, Christos; Koutsou, Giannis [Cyprus Institute, Nicosia (Cyprus). Computation-based Science and Technology Research Center; Alexandrou, Constantia; Constantinou, Martha; Hadjiyiannakou, Kyriakos [Cyprus Institute, Nicosia (Cyprus). Computation-based Science and Technology Research Center; Cyprus Univ. (Cyprus). Dept. of Physics; Jansen, Karl [DESY Zeuthen (Germany). NIC; Aviles-Casco, Alejandro Vaquero [INFN Sezione di Milano-Bicocca, Milano (Italy)

2015-11-15

We compute the disconnected quark loops contributions entering the determination of nucleon observables, by using a N{sub f}=2 ensemble of twisted mass fermions with a clover term at a pion mass m{sub π}=133 MeV. We employ exact deflation and implement all calculations in GPUs, enabling us to achieve large statistics and a good signal.

Lattice degeneracies of geometric fermions

International Nuclear Information System (INIS)

Raszillier, H.

1983-05-01

We give the minimal numbers of degrees of freedom carried by geometric fermions on all lattices of maximal symmetries in d = 2, 3, and 4 dimensions. These numbers are lattice dependent, but in the (free) continuum limit, part of the degrees of freedom have to escape to infinity by a Wilson mechanism built in, and 2sup(d) survive for any lattice. On self-reciprocal lattices we compare the minimal numbers of degrees of freedom of geometric fermions with the minimal numbers of naive fermions on these lattices and argue that these numbers are equal. (orig.)

Hydrographs Showing Groundwater Level Changes for Selected Wells in the Chambers-Clover Creek Watershed and Vicinity, Pierce County, Washington

Science.gov (United States)

Justin, G.B.; Julich, R.; Payne, K.L.

2009-01-01

Selected groundwater level hydrographs for the Chambers-Clover Creek watershed (CCCW) and vicinity, Washington, are presented in an interactive web-based map to illustrate changes in groundwater levels in and near the CCCW on a monthly and seasonal basis. Hydrographs are linked to points corresponding to the well location on an interactive map of the study area. Groundwater level data and well information from Federal, State, and local agencies were obtained from the U.S. Geological Survey National Water Information System (NWIS), Groundwater Site Inventory (GWSI) System.

Lattice gauge theory using parallel processors

International Nuclear Information System (INIS)

Lee, T.D.; Chou, K.C.; Zichichi, A.

1987-01-01

The book's contents include: Lattice Gauge Theory Lectures: Introduction and Current Fermion Simulations; Monte Carlo Algorithms for Lattice Gauge Theory; Specialized Computers for Lattice Gauge Theory; Lattice Gauge Theory at Finite Temperature: A Monte Carlo Study; Computational Method - An Elementary Introduction to the Langevin Equation, Present Status of Numerical Quantum Chromodynamics; Random Lattice Field Theory; The GF11 Processor and Compiler; and The APE Computer and First Physics Results; Columbia Supercomputer Project: Parallel Supercomputer for Lattice QCD; Statistical and Systematic Errors in Numerical Simulations; Monte Carlo Simulation for LGT and Programming Techniques on the Columbia Supercomputer; Food for Thought: Five Lectures on Lattice Gauge Theory

Lattice degeneracies of fermions

International Nuclear Information System (INIS)

Raszillier, H.

1983-10-01

We present a detailed description of the minimal degeneracies of geometric (Kaehler) fermions on all the lattices of maximal symmetries in n = 1, ..., 4 dimensions. We also determine the isolated orbits of the maximal symmetry groups, which are related to the minimal numbers of ''naive'' fermions on the reciprocals of these lattices. It turns out that on the self-reciprocal lattices the minimal numbers of naive fermions are equal to the minimal numbers of degrees of freedom of geometric fermions. The description we give relies on the close connection of the maximal lattice symmetry groups with (affine) Weyl groups of root systems of (semi-) simple Lie algebras. (orig.)

Critical thickness for the formation of misfit dislocations originating from prismatic slip in semipolar and nonpolar III-nitride heterostructures

KAUST Repository

Smirnov, A. M.; Young, E. C.; Bougrov, V. E.; Speck, J. S.; Romanov, A. E.

2016-01-01

We calculate the critical thickness for misfit dislocation (MD) formation in lattice mismatched semipolar and nonpolar III-nitride wurtzite semiconductor layers for the case of MDs originated from prismatic slip (PSMDs). It has been shown

Twisted 3D N=4 supersymmetric YM on deformed A{sub 3}{sup *} lattice

Energy Technology Data Exchange (ETDEWEB)

Saidi, El Hassan [Lab of High Energy Physics, Modeling and Simulations, Faculty of Science, University Mohamed V-Agdal, Morocco and Centre of Physics and Mathematics, CPM, Rabat (Morocco)

2014-01-15

We study a class of twisted 3D N=4 supersymmetric Yang-Mills (SYM) theory on particular 3-dimensional lattice L{sub 3D} formally denoted as L{sub 3D}{sup su{sub 3}×u{sub 1}} and given by non-trivial fibration L{sub 1D}{sup u{sub 1}}×L{sub 2D}{sup su{sub 3}} with base L{sub 2D}{sup su{sub 3}}=A{sub 2}{sup *}, the weight lattice of SU(3). We first, develop the twisted 3D N=4 SYM in continuum by using superspace method where the scalar supercharge Q is manifestly exhibited. Then, we show how to engineer the 3D lattice L{sub 3D}{sup su{sub 3}×u{sub 1}} that host this theory. After that we build the lattice action S{sub latt} invariant under the following three points: (i) U(N) gauge invariance, (ii) BRST symmetry, (iii) the S{sub 3} point group symmetry of L{sub 3D}{sup su{sub 3}×u{sub 1}}. Other features such as reduction to twisted 2D supersymmetry with 8 supercharges living on L{sub 2D}≡L{sub 2D}{sup su{sub 2}×u{sub 1}}, the extension to twisted maximal 5D SYM with 16 supercharges on lattice L{sub 5D}≡L{sub 5D}{sup su{sub 4}×u{sub 1}} as well as the relation with known results are also given.

Geometry of lattice field theory

International Nuclear Information System (INIS)

Honan, T.J.

1986-01-01

Using some tools of algebraic topology, a general formalism for lattice field theory is presented. The lattice is taken to be a simplicial complex that is also a manifold and is referred to as a simplicial manifold. The fields on this lattice are cochains, that are called lattice forms to emphasize the connections with differential forms in the continuum. This connection provides a new bridge between lattice and continuum field theory. A metric can be put onto this simplicial manifold by assigning lengths to every link or I-simplex of the lattice. Regge calculus is a way of defining general relativity on this lattice. A geometric discussion of Regge calculus is presented. The Regge action, which is a discrete form of the Hilbert action, is derived from the Hilbert action using distribution valued forms. This is a new derivation that emphasizes the underlying geometry. Kramers-Wannier duality in statistical mechanics is discussed in this general setting. Nonlinear field theories, which include gauge theories and nonlinear sigma models are discussed in the continuum and then are put onto a lattice. The main new result here is the generalization to curved spacetime, which consists of making the theory compatible with Regge calculus

Representation theory of lattice current algebras

International Nuclear Information System (INIS)

Alekseev, A.Yu.; Eidgenoessische Technische Hochschule, Zurich; Faddeev, L.D.; Froehlich, L.D.; Schomerus, V.; Kyoto Univ.

1996-04-01

Lattice current algebras were introduced as a regularization of the left-and right moving degrees of freedom in the WZNW model. They provide examples of lattice theories with a local quantum symmetry U q (G). Their representation theory is studied in detail. In particular, we construct all irreducible representations along with a lattice analogue of the fusion product for representations of the lattice current algebra. It is shown that for an arbitrary number of lattice sites, the representation categories of the lattice current algebras agree with their continuum counterparts. (orig.)

Oxygen perovskites with pentavalent ruthenium A/sub 2/sup(II)Bsup(III)Rusup(V)O/sub 6/ with Asup(II) = Ba, Sr

Energy Technology Data Exchange (ETDEWEB)

Bader, H; Kemmler-Sack, S [Tuebingen Univ. (Germany, F.R.). Lehrstuhl fuer Anorganische Chemie 2

1980-07-01

The perovskites Ba/sub 2/Bsup(III)Rusup(V)O/sub 6/ with Bsup(III) = La, Nd, Sm, Eu, Gd, Dy, Y are cubic (Bsup(III) = La: a = 8.54 A; Y: a = 8.33 A) with a partial order for Bsup(III) and Rusup(V). The Sc compound, Ba/sub 2/ScRuO/sub 6/, has a hexagonal 6L structure (a = 5.79 A; c = 14.22 A; sequence (hcc)/sub 2/). The lattice of the Sr perovskites, Sr/sub 2/Bsup(III)Rusup(V)O/sub 6/, with Bsup(III) = Eu, Gd, Dy, Y is rhombic distorted. The IR and FIR spectra are discussed.

ISABELLE lattice

International Nuclear Information System (INIS)

Smith, L.

1975-01-01

An analysis is given of a number of variants of the basic lattice of the planned ISABELLE storage rings. The variants were formed by removing cells from the normal part of the lattice and juggling the lengths of magnets, cells, and insertions in order to maintain a rational relation of circumference to that of the AGS and approximately the same dispersion. Special insertions, correction windings, and the working line with nonlinear resonances are discussed

Perovskites Ba/sub 2/Bsub(1/2)sup(I)Bsub(1/2)sup(III)Tesup(VI)O/sub 6/

Energy Technology Data Exchange (ETDEWEB)

Roller, H; Kemmler-Sack, S [Tuebingen Univ. (Germany, F.R.). Lehrstuhl fuer Anorganische Chemie 2

1980-07-01

Compounds of composition Ba/sub 2/Bsub(1/2)sup(I)Bsub(1/2)sup(III)Tesup(VI)O/sub 6/ with Bsup(I) = Li, Na; Bsup(III) = La, Pr, Nd, Sm, Eu, Gd, Tb, Ho, Yb, Y, In, Sc crystallize in a cubic 1:1 ordered perovskite structure. The vibrational spectroscopic investigations show, that more species of TeO/sub 6/ octahedra are present in the lattice.

Introduction to lattice gauge theory

International Nuclear Information System (INIS)

Gupta, R.

1987-01-01

The lattice formulation of Quantum Field Theory (QFT) can be exploited in many ways. We can derive the lattice Feynman rules and carry out weak coupling perturbation expansions. The lattice then serves as a manifestly gauge invariant regularization scheme, albeit one that is more complicated than standard continuum schemes. Strong coupling expansions: these give us useful qualitative information, but unfortunately no hard numbers. The lattice theory is amenable to numerical simulations by which one calculates the long distance properties of a strongly interacting theory from first principles. The observables are measured as a function of the bare coupling g and a gauge invariant cut-off ≅ 1/α, where α is the lattice spacing. The continuum (physical) behavior is recovered in the limit α → 0, at which point the lattice artifacts go to zero. This is the more powerful use of lattice formulation, so in these lectures the author focuses on setting up the theory for the purpose of numerical simulations to get hard numbers. The numerical techniques used in Lattice Gauge Theories have their roots in statistical mechanics, so it is important to develop an intuition for the interconnection between quantum mechanics and statistical mechanics. This will be the emphasis of the first lecture. In the second lecture, the author reviews the essential ingredients of formulating QCD on the lattice and discusses scaling and the continuum limit. In the last lecture the author summarizes the status of some of the main results. He also mentions the bottlenecks and possible directions for research. 88 refs

Crystal structures of fac-tri?chlorido?tris?(tri?methyl?phosphane-?P)rhodium(III) monohydrate and fac-tri?chlorido?tris?(tri?methyl?phosphane-?P)rhodium(III) methanol hemisolvate: rhodium structures that are isotypic with their iridium analogs

OpenAIRE

Merola, Joseph S.; Franks, Marion A.

2015-01-01

The crystal structures of two solvates of fac-tri-chlorido-tris-(tri-methyl-phosphane-κP)rhodium(III) are reported, i.e. one with water in the crystal lattice, fac-[RhCl3(Me3P)3]·H2O, and one with methanol in the crystal lattice, fac-[RhCl3(Me3P)3]·0.5CH3OH. These rhodium compounds exhibit distorted octahedral coordination spheres at the metal and are isotypic with the analogous iridium compounds previously reported by us [Merola et al. (2013 ▶). Polyhedron, 54, 67-73]. Comparison is made bet...

Equilibrium statistical mechanics of lattice models

CERN Document Server

Lavis, David A

2015-01-01

Most interesting and difficult problems in equilibrium statistical mechanics concern models which exhibit phase transitions. For graduate students and more experienced researchers this book provides an invaluable reference source of approximate and exact solutions for a comprehensive range of such models. Part I contains background material on classical thermodynamics and statistical mechanics, together with a classification and survey of lattice models. The geometry of phase transitions is described and scaling theory is used to introduce critical exponents and scaling laws. An introduction is given to finite-size scaling, conformal invariance and Schramm—Loewner evolution. Part II contains accounts of classical mean-field methods. The parallels between Landau expansions and catastrophe theory are discussed and Ginzburg—Landau theory is introduced. The extension of mean-field theory to higher-orders is explored using the Kikuchi—Hijmans—De Boer hierarchy of approximations. In Part III the use of alge...

Basis reduction for layered lattices

NARCIS (Netherlands)

Torreão Dassen, Erwin

2011-01-01

We develop the theory of layered Euclidean spaces and layered lattices. We present algorithms to compute both Gram-Schmidt and reduced bases in this generalized setting. A layered lattice can be seen as lattices where certain directions have infinite weight. It can also be

Basis reduction for layered lattices

NARCIS (Netherlands)

E.L. Torreão Dassen (Erwin)

2011-01-01

htmlabstractWe develop the theory of layered Euclidean spaces and layered lattices. With this new theory certain problems that usually are solved by using classical lattices with a "weighting" gain a new, more natural form. Using the layered lattice basis reduction algorithms introduced here these

Lattice-Based Revocable Certificateless Signature

Directory of Open Access Journals (Sweden)

Ying-Hao Hung

2017-10-01

Full Text Available Certificateless signatures (CLS are noticeable because they may resolve the key escrow problem in ID-based signatures and break away the management problem regarding certificate in conventional signatures. However, the security of the mostly previous CLS schemes relies on the difficulty of solving discrete logarithm or large integer factorization problems. These two problems would be solved by quantum computers in the future so that the signature schemes based on them will also become insecure. For post-quantum cryptography, lattice-based cryptography is significant due to its efficiency and security. However, no study on addressing the revocation problem in the existing lattice-based CLS schemes is presented. In this paper, we focus on the revocation issue and present the first revocable CLS (RCLS scheme over lattices. Based on the short integer solution (SIS assumption over lattices, the proposed lattice-based RCLS scheme is shown to be existential unforgeability against adaptive chosen message attacks. By performance analysis and comparisons, the proposed lattice-based RCLS scheme is better than the previously proposed lattice-based CLS scheme, in terms of private key size, signature length and the revocation mechanism.

Lattice Higgs models

International Nuclear Information System (INIS)

Jersak, J.

1986-01-01

This year has brought a sudden interest in lattice Higgs models. After five years of only modest activity we now have many new results obtained both by analytic and Monte Carlo methods. This talk is a review of the present state of lattice Higgs models with particular emphasis on the recent development

Nuclear lattice simulations

Directory of Open Access Journals (Sweden)

Epelbaum E.

2010-04-01

Full Text Available We review recent progress on nuclear lattice simulations using chiral effective field theory. We discuss lattice results for dilute neutron matter at next-to-leading order, three-body forces at next-to-next-toleading order, isospin-breaking and Coulomb effects, and the binding energy of light nuclei.

Magnetic states, correlation effects and metal-insulator transition in FCC lattice

Science.gov (United States)

Timirgazin, M. A.; Igoshev, P. A.; Arzhnikov, A. K.; Irkhin, V. Yu

2016-12-01

The ground-state magnetic phase diagram (including collinear and spiral states) of the single-band Hubbard model for the face-centered cubic lattice and related metal-insulator transition (MIT) are investigated within the slave-boson approach by Kotliar and Ruckenstein. The correlation-induced electron spectrum narrowing and a comparison with a generalized Hartree-Fock approximation allow one to estimate the strength of correlation effects. This, as well as the MIT scenario, depends dramatically on the ratio of the next-nearest and nearest electron hopping integrals {{t}\\prime}/t . In contrast with metallic state, possessing substantial band narrowing, insulator one is only weakly correlated. The magnetic (Slater) scenario of MIT is found to be superior over the Mott one. Unlike simple and body-centered cubic lattices, MIT is the first order transition (discontinuous) for most {{t}\\prime}/t . The insulator state is type-II or type-III antiferromagnet, and the metallic state is spin-spiral, collinear antiferromagnet or paramagnet depending on {{t}\\prime}/t . The picture of magnetic ordering is compared with that in the standard localized-electron (Heisenberg) model.

The role of diffusion measurements in the study of crystal lattice defects

Energy Technology Data Exchange (ETDEWEB)

Kidson, G V

1965-07-15

Measurements of atomic mobility in solids are frequently of direct interest to those concerned with the design, development and utilization of materials in engineering. Increasing attention, however, is currently devoted to an under standing of such properties in terms of the occurrence and nature of point and line defects in the crystals. This paper reviews some recent diffusion studies conducted at C.R,N.L. that provide, in addition to data of interest in nuclear technology, a means of gaining some insight into the more fundamental nature of the lattice defects occurring in the materials. The systems discussed are (i) self diffusion in the high temperature phase of pure zirconium (ii) solute diffusion in lead and (iii) interdiffusion of aluminum and zirconium The unusual and at present incompletely understood results described in (i) are briefly reviewed. Evidence is given to suggest that diffusion occurs either through a dense dislocation network produced as a result of a martensitic phase transformation, or, alternatively, by excess vacancies introduced into the crystal by impurities. In (ii) the extraordinarily rapid diffusion of noble metal solutes in high purity lead single crystals will be discussed n terms of the state of solution of the solute atoms. It will be shown that their diffusion behaviour can be understood by assuming that a fraction f{sub i} of the dissolved solute atoms occupy interstitial sites, The measured diffusion coefficient D{sub m} is related to the interstitial diffusion coefficient by D{sub m} = f{sub i} D{sub i}. In (iii) the formation and rapid growth of single intermetallic compound ZrAl{sub 3} in the diffusion zone formed between pure zirconium and pure aluminum is described and the diffusion mechanism is interpreted in terms of the structure of the compound lattice. The results indicate that ZrAl{sub 3} forms a defect lattice, leading to the relatively rapid migration of aluminum atoms. (author)

Computing the writhe on lattices

International Nuclear Information System (INIS)

Laing, C; Sumners, D W

2006-01-01

Given a polygonal closed curve on a lattice or space group, we describe a method for computing the writhe of the curve as the average of weighted projected writhing numbers of the polygon in a few directions. These directions are determined by the lattice geometry, the weights are determined by areas of regions on the unit 2-sphere, and the regions are formed by the tangent indicatrix to the polygonal curve. We give a new formula for the writhe of polygons on the face centred cubic lattice and prove that the writhe of polygons on the body centred cubic lattice, the hexagonal simple lattice, and the diamond space group is always a rational number, and discuss applications to ring polymers

Hyper-lattice algebraic model for data warehousing

CERN Document Server

Sen, Soumya; Chaki, Nabendu

2016-01-01

This book presents Hyper-lattice, a new algebraic model for partially ordered sets, and an alternative to lattice. The authors analyze some of the shortcomings of conventional lattice structure and propose a novel algebraic structure in the form of Hyper-lattice to overcome problems with lattice. They establish how Hyper-lattice supports dynamic insertion of elements in a partial order set with a partial hierarchy between the set members. The authors present the characteristics and the different properties, showing how propositions and lemmas formalize Hyper-lattice as a new algebraic structure.

An overview of lattice QCD

International Nuclear Information System (INIS)

Woloshyn, R.M.

1988-03-01

The basic concepts of the Lagrangian formulation of lattice field theory are discussed. The Wilson and staggered schemes for dealing with fermions on the lattice are described. Some recent results for hadron masses and vector and axial vector current matrix elements in lattice QCD are reviewed. (Author) (118 refs., 16 figs.)

Resistance of red clover (Trifolium pratense) to the root parasitic plant Orobanche minor is activated by salicylate but not by jasmonate.

Science.gov (United States)

Kusumoto, Dai; Goldwasser, Yaakov; Xie, Xiaonan; Yoneyama, Kaori; Takeuchi, Yasutomo; Yoneyama, Koichi

2007-09-01

Obligate root holoparasites of the genus Orobanche attack dicotyledonous crops and cause severe losses in many parts of the world. Chemical induction of plant defence systems such as systemic acquired resistance was proposed to be an available strategy to control the root parasite, but the detailed mechanisms involved have not been clarified. The aim of this study was to elucidate the effects of salicylic acid (SA), jasmonic acid (JA) and their analogues on resistance of red clover to Orobanche parasitism. Roots of red clover grown in plastic chambers were applied with SA, S-methyl benzo[1,2,3]thiadiazole-7-carbothioate (BTH), methyl jasmonate (MeJA) and n-propyl dihydrojasmonate (PDJ), and then were inoculated with O. minor seeds. Attachments of the parasite were observed after 5 weeks. SA and BTH, inducers of SA-mediated defences, significantly reduced the number of established parasites by more than 75 %. By contrast, MeJA and PDJ, inducers of JA-mediated defences, did not affect parasitism. The reduction in the number of established parasites by SA and BTH was due to the inhibited elongation of O. minor radicles and the activation of defence responses in the host root including lignification of the endodermis. These results suggest that SA-induced resistance, but not JA-induced resistance, is effective in inhibiting Orobanche parasitism and that the resistance is expressed by the host root both externally and internally.

Hadron structure from lattice QCD

International Nuclear Information System (INIS)

Schaefer, Andreas

2008-01-01

Some elements and current developments of lattice QCD are reviewed, with special emphasis on hadron structure observables. In principle, high precision experimental and lattice data provide nowadays a very detailled picture of the internal structure of hadrons. However, to relate both, a very good controle of perturbative QCD is needed in many cases. Finally chiral perturbation theory is extremely helpful to boost the precision of lattice calculations. The mutual need and benefit of all four elements: experiment, lattice QCD, perturbative QCD and chiral perturbation theory is the main topic of this review

Lattice formulations of reggeon interactions

International Nuclear Information System (INIS)

Brower, R.C.; Ellis, J.; Savit, R.; Zinn-Justin, J.

1976-01-01

A class of lattice analogues to reggeon field theory is examined. First the transition from a continuum to a lattice field theory is discussed, emphasizing the necessity of a Wick rotation and the consideration of symmetry properties. Next the theory is transformed to a discrete system with two spins at each lattice site, and the problems of the triple-reggeon interaction and the reggeon energy gap are discussed. It is pointed out that transferring the theory from the continuum to a lattice necesarily introduces new relevant operators not normally present in reggeon field theory. (Auth.)

Irreversible stochastic processes on lattices

International Nuclear Information System (INIS)

Nord, R.S.

1986-01-01

Models for irreversible random or cooperative filling of lattices are required to describe many processes in chemistry and physics. Since the filling is assumed to be irreversible, even the stationary, saturation state is not in equilibrium. The kinetics and statistics of these processes are described by recasting the master equations in infinite hierarchical form. Solutions can be obtained by implementing various techniques: refinements in these solution techniques are presented. Programs considered include random dimer, trimer, and tetramer filling of 2D lattices, random dimer filling of a cubic lattice, competitive filling of two or more species, and the effect of a random distribution of inactive sites on the filling. Also considered is monomer filling of a linear lattice with nearest neighbor cooperative effects and solve for the exact cluster-size distribution for cluster sizes up to the asymptotic regime. Additionally, a technique is developed to directly determine the asymptotic properties of the cluster size distribution. Finally cluster growth is considered via irreversible aggregation involving random walkers. In particular, explicit results are provided for the large-lattice-size asymptotic behavior of trapping probabilities and average walk lengths for a single walker on a lattice with multiple traps. Procedures for exact calculation of these quantities on finite lattices are also developed

Effects of Seeding Density and Nitrogen Fertilizer on the Productivity of Egyptian Clover

Directory of Open Access Journals (Sweden)

Jwan G. Rafaat

2013-11-01

Full Text Available The study was carried out to show the effect of different levels of nitrogen fertilizer 0, 20, 40 and 60 kg urea/ha, and two seeding rates 15 and 30 kg/ha. The study was conducted at Bakrajo research field during the winter season 2011-2012 to some growth characteristics of Egyptian clover, such as plant height, dry leaf weight percent, dry stem weight percent, leave stem ratio, fresh yield t/ha, dry yield t/ha and dry matter percent. The experiment was designed as (R.C.B.D. The results can be summarized as follow; significant differences were observed between all three cuts, and the third cut was superior in almost characters especially in the forage yield. The application of 40 and 60 kg urea gave maximum yield. Using 15 kg seeds/ha showed superior value due to fresh yield in compare to 30 kg for all cutting, while the dry yield responded non-significantly to seeding rates.

Non-Abelian vortex lattices

Science.gov (United States)

Tallarita, Gianni; Peterson, Adam

2018-04-01

We perform a numerical study of the phase diagram of the model proposed in [M. Shifman, Phys. Rev. D 87, 025025 (2013)., 10.1103/PhysRevD.87.025025], which is a simple model containing non-Abelian vortices. As per the case of Abrikosov vortices, we map out a region of parameter space in which the system prefers the formation of vortices in ordered lattice structures. These are generalizations of Abrikosov vortex lattices with extra orientational moduli in the vortex cores. At sufficiently large lattice spacing the low energy theory is described by a sum of C P (1 ) theories, each located on a vortex site. As the lattice spacing becomes smaller, when the self-interaction of the orientational field becomes relevant, only an overall rotation in internal space survives.

Ordered perovskites with cationic vacancies. 4. Compounds of type Ba/sub 6/B/sub 2/sup(III)vacantTe/sub 3/sup(VI)O/sub 18/

Energy Technology Data Exchange (ETDEWEB)

Schittenhelm, H J; Kemmler-Sack, S [Tuebingen Univ. (Germany, F.R.). Lehrstuhl fuer Anorganische Chemie 2

1979-07-01

Compounds of the composition Ba/sub 6/B(III)/sub 2/vacantTe(VI)/sub 3/O/sub 18/ equivalent to Ba/sub 2/Ba(III)sub(2/3)vacantsub(1/3)Te(VI)O/sub 6/, with B(III) = Pr, Nd, Sm-Lu, Y crystallize with a cubic perovskite lattice. The cell parameters diminish as the size of B(III) falls (B(III) = Pr: a = 8.52 A; Lu: a = 8.33 A). In contrast to the corresponding perovskites with U(VI) and W(VI) no polymorphism is observed.

Superspace approach to lattice supersymmetry

International Nuclear Information System (INIS)

Kostelecky, V.A.; Rabin, J.M.

1984-01-01

We construct a cubic lattice of discrete points in superspace, as well as a discrete subgroup of the supersymmetry group which maps this ''superlattice'' into itself. We discuss the connection between this structure and previous versions of lattice supersymmetry. Our approach clarifies the mathematical problems of formulating supersymmetric lattice field theories and suggests new methods for attacking them

Dynamical lattice theory

International Nuclear Information System (INIS)

Chodos, A.

1978-01-01

A version of lattice gauge theory is presented in which the shape of the lattice is not assumed at the outset but is a consequence of the dynamics. Other related features which are not specified a priori include the internal and space-time symmetry groups and the dimensionality of space-time. The theory possesses a much larger invariance group than the usual gauge group on a lattice, and has associated with it an integer k 0 analogous to the topological quantum numer of quantum chromodynamics. Families of semiclassical solutions are found which are labeled by k 0 and a second integer x, but the analysis is not carried far enough to determine which space-time and internal symmetry groups characterize the lowest-lying states of the theory

A status report of the QCDSF N{sub f}=2+1 project

Energy Technology Data Exchange (ETDEWEB)

Goeckeler, Meinulf [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Horsley, Roger [Edinburgh Univ. (United Kingdom). School of Physics; Nakamura, Yoshifumi [DESY, Zeuthen (DE). John von Neumann Institute NIC] (and others)

2007-12-20

We report about on-going simulations of N{sub f}=2+1 lattice QCD. We use a tadpole improved Symanzik gauge action and stout link smeared Wilson fermions with a clover term. We employ the Hasenbusch trick for the degenerate u- and d-quarks, and the RHMC algorithm for the simulation of the strange quark. (orig.)

Rational solutions of the discrete time Toda lattice and the alternate discrete Painleve II equation

International Nuclear Information System (INIS)

Common, Alan K; Hone, Andrew N W

2008-01-01

The Yablonskii-Vorob'ev polynomials y n (t), which are defined by a second-order bilinear differential-difference equation, provide rational solutions of the Toda lattice. They are also polynomial tau-functions for the rational solutions of the second Painleve equation (P II ). Here we define two-variable polynomials Y n (t, h) on a lattice with spacing h, by considering rational solutions of the discrete time Toda lattice as introduced by Suris. These polynomials are shown to have many properties that are analogous to those of the Yablonskii-Vorob'ev polynomials, to which they reduce when h = 0. They also provide rational solutions for a particular discretization of P II , namely the so-called alternate discrete P II , and this connection leads to an expression in terms of the Umemura polynomials for the third Painleve equation (P III ). It is shown that the Baecklund transformation for the alternate discrete Painleve equation is a symplectic map, and the shift in time is also symplectic. Finally we present a Lax pair for the alternate discrete P II , which recovers Jimbo and Miwa's Lax pair for P II in the continuum limit h → 0

Observation of electron polarization above 80% in photoemission from strained III-V compounds

International Nuclear Information System (INIS)

Garwin, E.L.; Maruyama, T.; Prepost, R.; Zapalac, G.H.

1992-02-01

Spin-polarized electron photoemission has been investigated for strained III--V compounds; (1) strained In x Ga 1-x As epitaxially grown on a GaAs substrate, and (2) strained GaAs grown on a GaAs 1-x P x buffer layer. The lattice mismatched heterostructure results in a highly strained epitaxial layer, and electron spin polarization as high as 90% has been observed

Computing nucleon EDM on a lattice

Science.gov (United States)

Abramczyk, Michael; Aoki, Sinya; Blum, Tom; Izubuchi, Taku; Ohki, Hiroshi; Syritsyn, Sergey

2018-03-01

I will discuss briefly recent changes in the methodology of computing the baryon EDM on a lattice. The associated correction substantially reduces presently existing lattice values for the proton and neutron theta-induced EDMs, so that even the most precise previous lattice results become consistent with zero. On one hand, this change removes previous disagreements between these lattice results and the phenomenological estimates of the nucleon EDM. On the other hand, the nucleon EDM becomes much harder to compute on a lattice. In addition, I will review the progress in computing quark chromo-EDM-induced nucleon EDM using chiral quark action.

Computing nucleon EDM on a lattice

Energy Technology Data Exchange (ETDEWEB)

Abramczyk, Michael; Izubuchi, Taku

2017-06-18

I will discuss briefly recent changes in the methodology of computing the baryon EDM on a lattice. The associated correction substantially reduces presently existing lattice values for the proton and neutron theta-induced EDMs, so that even the most precise previous lattice results become consistent with zero. On one hand, this change removes previous disagreements between these lattice results and the phenomenological estimates of the nucleon EDM. On the other hand, the nucleon EDM becomes much harder to compute on a lattice. In addition, I will review the progress in computing quark chromo-EDM-induced nucleon EDM using chiral quark action.

Cold collisions in dissipative optical lattices

International Nuclear Information System (INIS)

Piilo, J; Suominen, K-A

2005-01-01

The invention of laser cooling methods for neutral atoms allows optical and magnetic trapping of cold atomic clouds in the temperature regime below 1 mK. In the past, light-assisted cold collisions between laser cooled atoms have been widely studied in magneto-optical atom traps (MOTs). We describe here theoretical studies of dynamical interactions, specifically cold collisions, between atoms trapped in near-resonant, dissipative optical lattices. The extension of collision studies to the regime of optical lattices introduces several complicating factors. For the lattice studies, one has to account for the internal substates of atoms, position-dependent matter-light coupling, and position-dependent couplings between the atoms, in addition to the spontaneous decay of electronically excited atomic states. The developed one-dimensional quantum-mechanical model combines atomic cooling and collision dynamics in a single framework. The model is based on Monte Carlo wavefunction simulations and is applied when the lattice-creating lasers have frequencies both below (red-detuned lattice) and above (blue-detuned lattice) the atomic resonance frequency. It turns out that the radiative heating mechanism affects the dynamics of atomic cloud in a red-detuned lattice in a way that is not directly expected from the MOT studies. The optical lattice and position-dependent light-matter coupling introduces selectivity of collision partners. The atoms which are most mobile and energetic are strongly favoured to participate in collisions, and are more often ejected from the lattice, than the slow ones in the laser parameter region selected for study. Consequently, the atoms remaining in the lattice have a smaller average kinetic energy per atom than in the case of non-interacting atoms. For blue-detuned lattices, we study how optical shielding emerges as a natural part of the lattice and look for ways to optimize the effect. We find that the cooling and shielding dynamics do not mix

Topological magnon bands in ferromagnetic star lattice

International Nuclear Information System (INIS)

Owerre, S A

2017-01-01

The experimental observation of topological magnon bands and thermal Hall effect in a kagomé lattice ferromagnet Cu(1–3, bdc) has inspired the search for topological magnon effects in various insulating ferromagnets that lack an inversion center allowing a Dzyaloshinskii–Moriya (DM) spin–orbit interaction. The star lattice (also known as the decorated honeycomb lattice) ferromagnet is an ideal candidate for this purpose because it is a variant of the kagomé lattice with additional links that connect the up-pointing and down-pointing triangles. This gives rise to twice the unit cell of the kagomé lattice, and hence more interesting topological magnon effects. In particular, the triangular bridges on the star lattice can be coupled either ferromagnetically or antiferromagnetically which is not possible on the kagomé lattice ferromagnets. Here, we study DM-induced topological magnon bands, chiral edge modes, and thermal magnon Hall effect on the star lattice ferromagnet in different parameter regimes. The star lattice can also be visualized as the parent material from which topological magnon bands can be realized for the kagomé and honeycomb lattices in some limiting cases. (paper)

Topological magnon bands in ferromagnetic star lattice.

Science.gov (United States)

Owerre, S A

2017-05-10

The experimental observation of topological magnon bands and thermal Hall effect in a kagomé lattice ferromagnet Cu(1-3, bdc) has inspired the search for topological magnon effects in various insulating ferromagnets that lack an inversion center allowing a Dzyaloshinskii-Moriya (DM) spin-orbit interaction. The star lattice (also known as the decorated honeycomb lattice) ferromagnet is an ideal candidate for this purpose because it is a variant of the kagomé lattice with additional links that connect the up-pointing and down-pointing triangles. This gives rise to twice the unit cell of the kagomé lattice, and hence more interesting topological magnon effects. In particular, the triangular bridges on the star lattice can be coupled either ferromagnetically or antiferromagnetically which is not possible on the kagomé lattice ferromagnets. Here, we study DM-induced topological magnon bands, chiral edge modes, and thermal magnon Hall effect on the star lattice ferromagnet in different parameter regimes. The star lattice can also be visualized as the parent material from which topological magnon bands can be realized for the kagomé and honeycomb lattices in some limiting cases.

Introduction to lattice gauge theories

International Nuclear Information System (INIS)

La Cock, P.

1988-03-01

A general introduction to Lattice Gauge Theory (LGT) is given. The theory is discussed from first principles to facilitate an understanding of the techniques used in LGT. These include lattice formalism, gauge invariance, fermions on the lattice, group theory and integration, strong coupling methods and mean field techniques. A review of quantum chromodynamics on the lattice at finite temperature and density is also given. Monte Carlo results and analytical methods are discussed. An attempt has been made to include most relevant data up to the end of 1987, and to update some earlier reviews existing on the subject. 224 refs., 33 figs., 14 tabs

Angles in hyperbolic lattices

DEFF Research Database (Denmark)

Risager, Morten S.; Södergren, Carl Anders

2017-01-01

It is well known that the angles in a lattice acting on hyperbolic n -space become equidistributed. In this paper we determine a formula for the pair correlation density for angles in such hyperbolic lattices. Using this formula we determine, among other things, the asymptotic behavior of the den......It is well known that the angles in a lattice acting on hyperbolic n -space become equidistributed. In this paper we determine a formula for the pair correlation density for angles in such hyperbolic lattices. Using this formula we determine, among other things, the asymptotic behavior...... of the density function in both the small and large variable limits. This extends earlier results by Boca, Pasol, Popa and Zaharescu and Kelmer and Kontorovich in dimension 2 to general dimension n . Our proofs use the decay of matrix coefficients together with a number of careful estimates, and lead...

Working Group Report: Lattice Field Theory

Energy Technology Data Exchange (ETDEWEB)

Blum, T.; et al.,

2013-10-22

This is the report of the Computing Frontier working group on Lattice Field Theory prepared for the proceedings of the 2013 Community Summer Study ("Snowmass"). We present the future computing needs and plans of the U.S. lattice gauge theory community and argue that continued support of the U.S. (and worldwide) lattice-QCD effort is essential to fully capitalize on the enormous investment in the high-energy physics experimental program. We first summarize the dramatic progress of numerical lattice-QCD simulations in the past decade, with some emphasis on calculations carried out under the auspices of the U.S. Lattice-QCD Collaboration, and describe a broad program of lattice-QCD calculations that will be relevant for future experiments at the intensity and energy frontiers. We then present details of the computational hardware and software resources needed to undertake these calculations.

Ising antiferromagnet on the Archimedean lattices

Science.gov (United States)

Yu, Unjong

2015-06-01

Geometric frustration effects were studied systematically with the Ising antiferromagnet on the 11 Archimedean lattices using the Monte Carlo methods. The Wang-Landau algorithm for static properties (specific heat and residual entropy) and the Metropolis algorithm for a freezing order parameter were adopted. The exact residual entropy was also found. Based on the degree of frustration and dynamic properties, ground states of them were determined. The Shastry-Sutherland lattice and the trellis lattice are weakly frustrated and have two- and one-dimensional long-range-ordered ground states, respectively. The bounce, maple-leaf, and star lattices have the spin ice phase. The spin liquid phase appears in the triangular and kagome lattices.

Statistical hydrodynamics of lattice-gas automata

OpenAIRE

Grosfils, Patrick; Boon, Jean-Pierre; Brito López, Ricardo; Ernst, M. H.

1993-01-01

We investigate the space and time behavior of spontaneous thermohydrodynamic fluctuations in a simple fluid modeled by a lattice-gas automaton and develop the statistical-mechanical theory of thermal lattice gases to compute the dynamical structure factor, i.e., the power spectrum of the density correlation function. A comparative analysis of the theoretical predictions with our lattice gas simulations is presented. The main results are (i) the spectral function of the lattice-gas fluctuation...

On the performance of 1-level LDPC lattices

OpenAIRE

Sadeghi, Mohammad-Reza; Sakzad, Amin

2013-01-01

The low-density parity-check (LDPC) lattices perform very well in high dimensions under generalized min-sum iterative decoding algorithm. In this work we focus on 1-level LDPC lattices. We show that these lattices are the same as lattices constructed based on Construction A and low-density lattice-code (LDLC) lattices. In spite of having slightly lower coding gain, 1-level regular LDPC lattices have remarkable performances. The lower complexity nature of the decoding algorithm for these type ...

Spatial classification with fuzzy lattice reasoning

NARCIS (Netherlands)

Mavridis, Constantinos; Athanasiadis, I.N.

2017-01-01

This work extends the Fuzzy Lattice Reasoning (FLR) Classifier to manage spatial attributes, and spatial relationships. Specifically, we concentrate on spatial entities, as countries, cities, or states. Lattice Theory requires the elements of a Lattice to be partially ordered. To match such

Fuel lattice design using heuristics and new strategies

Energy Technology Data Exchange (ETDEWEB)

Ortiz S, J. J.; Castillo M, J. A.; Torres V, M.; Perusquia del Cueto, R. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Pelta, D. A. [ETS Ingenieria Informatica y Telecomunicaciones, Universidad de Granada, Daniel Saucedo Aranda s/n, 18071 Granada (Spain); Campos S, Y., E-mail: juanjose.ortiz@inin.gob.m [IPN, Escuela Superior de Fisica y Matematicas, Unidad Profesional Adolfo Lopez Mateos, Edif. 9, 07738 Mexico D. F. (Mexico)

2010-10-15

This work show some results of the fuel lattice design in BWRs when some allocation pin rod rules are not taking into account. Heuristics techniques like Path Re linking and Greedy to design fuel lattices were used. The scope of this work is to search about how do classical rules in design fuel lattices affect the heuristics techniques results and the fuel lattice quality. The fuel lattices quality is measured by Power Peaking Factor and Infinite Multiplication Factor at the beginning of the fuel lattice life. CASMO-4 code to calculate these parameters was used. The analyzed rules are the following: pin rods with lowest uranium enrichment are only allocated in the fuel lattice corner, and pin rods with gadolinium cannot allocated in the fuel lattice edge. Fuel lattices with and without gadolinium in the main diagonal were studied. Some fuel lattices were simulated in an equilibrium cycle fuel reload, using Simulate-3 to verify their performance. So, the effective multiplication factor and thermal limits can be verified. The obtained results show a good performance in some fuel lattices designed, even thought, the knowing rules were not implemented. A fuel lattice performance and fuel lattice design characteristics analysis was made. To the realized tests, a dell workstation was used, under Li nux platform. (Author)

Fuel lattice design using heuristics and new strategies

International Nuclear Information System (INIS)

Ortiz S, J. J.; Castillo M, J. A.; Torres V, M.; Perusquia del Cueto, R.; Pelta, D. A.; Campos S, Y.

2010-10-01

This work show some results of the fuel lattice design in BWRs when some allocation pin rod rules are not taking into account. Heuristics techniques like Path Re linking and Greedy to design fuel lattices were used. The scope of this work is to search about how do classical rules in design fuel lattices affect the heuristics techniques results and the fuel lattice quality. The fuel lattices quality is measured by Power Peaking Factor and Infinite Multiplication Factor at the beginning of the fuel lattice life. CASMO-4 code to calculate these parameters was used. The analyzed rules are the following: pin rods with lowest uranium enrichment are only allocated in the fuel lattice corner, and pin rods with gadolinium cannot allocated in the fuel lattice edge. Fuel lattices with and without gadolinium in the main diagonal were studied. Some fuel lattices were simulated in an equilibrium cycle fuel reload, using Simulate-3 to verify their performance. So, the effective multiplication factor and thermal limits can be verified. The obtained results show a good performance in some fuel lattices designed, even thought, the knowing rules were not implemented. A fuel lattice performance and fuel lattice design characteristics analysis was made. To the realized tests, a dell workstation was used, under Li nux platform. (Author)

Pion parton distribution functions from lattice QCD

International Nuclear Information System (INIS)

Wetzorke, I.; Jansen, K.; Shindler, A.; Palombi, F.

2003-09-01

We report on recent results for the pion matrix element of the twist-2 operator corresponding to the average momentum of non-singlet quark densities. For the first time finite volume effects of this matrix element are investigated and come out to be surprisingly large. We use standard Wilson and non-perturbatively improved clover actions in order to control better the extrapolation to the continuum limit. Moreover, we compute, fully non-perturbatively, the renormalization group invariant matrix element, which allows a comparison with experimental results in a broad range of energy scales. Finally, we discuss the remaining uncertainties, the extrapolation to the chiral limit and the quenched approximation. (orig.)

Quantum transport in d -dimensional lattices

International Nuclear Information System (INIS)

Manzano, Daniel; Chuang, Chern; Cao, Jianshu

2016-01-01

We show that both fermionic and bosonic uniform d -dimensional lattices can be reduced to a set of independent one-dimensional chains. This reduction leads to the expression for ballistic energy fluxes in uniform fermionic and bosonic lattices. By the use of the Jordan–Wigner transformation we can extend our analysis to spin lattices, proving the coexistence of both ballistic and non-ballistic subspaces in any dimension and for any system size. We then relate the nature of transport to the number of excitations in the homogeneous spin lattice, indicating that a single excitation always propagates ballistically and that the non-ballistic behaviour of uniform spin lattices is a consequence of the interaction between different excitations. (paper)

Embedded Lattice and Properties of Gram Matrix

Directory of Open Access Journals (Sweden)

Futa Yuichi

2017-03-01

Full Text Available In this article, we formalize in Mizar [14] the definition of embedding of lattice and its properties. We formally define an inner product on an embedded module. We also formalize properties of Gram matrix. We formally prove that an inverse of Gram matrix for a rational lattice exists. Lattice of Z-module is necessary for lattice problems, LLL (Lenstra, Lenstra and Lov´asz base reduction algorithm [16] and cryptographic systems with lattice [17].

Transmission Electron Microscope Measures Lattice Parameters

Science.gov (United States)

Pike, William T.

1996-01-01

Convergent-beam microdiffraction (CBM) in thermionic-emission transmission electron microscope (TEM) is technique for measuring lattice parameters of nanometer-sized specimens of crystalline materials. Lattice parameters determined by use of CBM accurate to within few parts in thousand. Technique developed especially for use in quantifying lattice parameters, and thus strains, in epitaxial mismatched-crystal-lattice multilayer structures in multiple-quantum-well and other advanced semiconductor electronic devices. Ability to determine strains in indivdual layers contributes to understanding of novel electronic behaviors of devices.

Lattice vibrations in α-boron

International Nuclear Information System (INIS)

Richter, W.

1976-01-01

α-rhombohedral boron is the simplest boron modification, with only 12 atoms per unit cell. The boron atoms are arranged in B 12 icosahedra, which are centered at the lattice points of a primitive rhombohedral lattice. The icosahedra are slightly deformed, as the five-fold symmetry of the ideal icosahedron is incompatible with any crystal structure. The lattice dynamics of α-boron are discussed in terms of the model developed by Weber and Thorpe. (Auth.)

Galilean invariant lattice Boltzmann scheme for natural convection on square and rectangular lattices

NARCIS (Netherlands)

Sman, van der R.G.M.

2006-01-01

In this paper we present lattice Boltzmann (LB) schemes for convection diffusion coupled to fluid flow on two-dimensional rectangular lattices. Via inverse Chapman-Enskog analysis of LB schemes including source terms, we show that for consistency with physics it is required that the moments of the

A comparison of measurements on PuO{sub 2}-UO{sub 2} fuelled graphite lattices with calculations using the ARGOSY method

Energy Technology Data Exchange (ETDEWEB)

King, D C [General Reactor Physics Division, Atomic Energy Establishment, Winfrith, Dorchester, Dorset (United Kingdom)

1966-01-15

The predictions of the ARGOSY method of calculation are compared with buckling and reaction rate measurements on graphite lattices containing plutonium enriched oxide cluster fuels. Most of the measurements were obtained on one lattice pitch giving a graphite-to-fuel volume ratio similar to that in the Windscale A.G.R. Apart from a reduction of 10% in the values of the capture and fission resonance integrals (4eV to 10KeV) of all nuclides the method as coded in ARGOSY III uses basic nuclear data. It is shown in this report that the buckling predictions of ARGOSY III at room temperature are in agreement with the experimentally determined values within approximately the experimental error, i.e. equivalent to {+-}0.5% in reactivity. When systematic errors are removed, however, a linear trend with the fraction of fissions occurring in Pu 239 is evident; the calculated reactivity being (0.6 {+-} 0.3)% low for zero Pu239 content and (0.6 + 0.3)% high for fuel with 80% of fission occurring in Pu 239. The experimentally determined change of buckling between 20 and 390 deg C is predicted to within the experimental error, i,e. equivalent to {+-} 0.7 mn/deg C. Reaction rate ratios and radial power distributions at all temperatures are predicted well by ARGOSY III. (author)

INL Results for Phases I and III of the OECD/NEA MHTGR-350 Benchmark

Energy Technology Data Exchange (ETDEWEB)

Gerhard Strydom; Javier Ortensi; Sonat Sen; Hans Hammer

2013-09-01

The Idaho National Laboratory (INL) Very High Temperature Reactor (VHTR) Technology Development Office (TDO) Methods Core Simulation group led the construction of the Organization for Economic Cooperation and Development (OECD) Modular High Temperature Reactor (MHTGR) 350 MW benchmark for comparing and evaluating prismatic VHTR analysis codes. The benchmark is sponsored by the OECD's Nuclear Energy Agency (NEA), and the project will yield a set of reference steady-state, transient, and lattice depletion problems that can be used by the Department of Energy (DOE), the Nuclear Regulatory Commission (NRC), and vendors to assess their code suits. The Methods group is responsible for defining the benchmark specifications, leading the data collection and comparison activities, and chairing the annual technical workshops. This report summarizes the latest INL results for Phase I (steady state) and Phase III (lattice depletion) of the benchmark. The INSTANT, Pronghorn and RattleSnake codes were used for the standalone core neutronics modeling of Exercise 1, and the results obtained from these codes are compared in Section 4. Exercise 2 of Phase I requires the standalone steady-state thermal fluids modeling of the MHTGR-350 design, and the results for the systems code RELAP5-3D are discussed in Section 5. The coupled neutronics and thermal fluids steady-state solution for Exercise 3 are reported in Section 6, utilizing the newly developed Parallel and Highly Innovative Simulation for INL Code System (PHISICS)/RELAP5-3D code suit. Finally, the lattice depletion models and results obtained for Phase III are compared in Section 7. The MHTGR-350 benchmark proved to be a challenging simulation set of problems to model accurately, and even with the simplifications introduced in the benchmark specification this activity is an important step in the code-to-code verification of modern prismatic VHTR codes. A final OECD/NEA comparison report will compare the Phase I and III

Elastic lattice in an incommensurate background

International Nuclear Information System (INIS)

Dickman, R.; Chudnovsky, E.M.

1995-01-01

We study a harmonic triangular lattice, which relaxes in the presence of an incommensurate short-wavelength potential. Monte Carlo simulations reveal that the elastic lattice exhibits only short-ranged translational correlations, despite the absence of defects in either lattice. Extended orientational order, however, persists in the presence of the background. Translational correlation lengths exhibit approximate power-law dependence upon cooling rate and background strength. Our results may be relevant to Wigner crystals, atomic monolayers on crystals surfaces, and flux-line and magnetic bubble lattices

Lattice gravity near the continuum limit

International Nuclear Information System (INIS)

Feinberg, G.; Friedberg, R.; Lee, T.D.; Ren, H.C.

1984-01-01

We prove that the lattice gravity always approaches the usual continuum limit when the link length l -> 0, provided that certain general boundary conditions are satisfied. This result holds for any lattice, regular or irregular. Furthermore, for a given lattice, the deviation from its continuum limit can be expressed as a power series in l 2 . General formulas for such a perturbative calculation are given, together with a number of illustrative examples, including the graviton propagator. The lattice gravity satisfies all the invariance properties of Einstein's theory of general relativity. In addition, it is symmetric under a new class of transformations that are absent in the usual continuum theory. The possibility that the lattice theory (with a nonzero l) may be more fundamental is discussed. (orig.)

Lattices for the TRIUMF KAON factory

International Nuclear Information System (INIS)

Servranckx, R.V.; Craddock, M.K.

1989-09-01

Separated-function racetrack lattices have been developed for the KAON Factory accelerators that have more flexibility than the old circular lattices. The arcs of the large rings have a regular FODO structure with a superimposed six-fold symmetric modulation of the betafunction in order to raise γ t to infinity. Straight sections with zero dispersion are provided for rf cavities and fast injection and extraction, and with controlled dispersion for H - injection and slow extraction. For the small rings, sixfold symmetric circular lattices with high γ t are retained. In the Accumulator lattice, a straight section with double waist and controlled η function allows for H - injection and phase-space painting. The ion-optical properties of the lattices and the results from tracking studies are discussed

Immunogold Labelling to Localize Polyphenol Oxidase (PPO) During Wilting of Red Clover Leaf Tissue and the Effect of Removing Cellular Matrices on PPO Protection of Glycerol-Based Lipid in the Rumen

Science.gov (United States)

The enzyme polyphenol oxidase (PPO) reduces the extent of proteolysis and lipolysis within red clover fed to ruminants. PPO catalyses the conversion of phenols to quinones which can react with nucleophilic cellular constituents (e.g. proteins), forming protein-phenol complexes that may reduce protei...

Proportional crosstalk correction for the segmented clover at iThemba LABS

International Nuclear Information System (INIS)

Bucher, T D; Noncolela, S P; Lawrie, E A; Dinoko, T R S; Easton, J L; Erasmus, N; Lawrie, J J; Mthembu, S H; Mtshali, W X; Shirinda, O; Orce, J N

2017-01-01

Reaching new depths in nuclear structure investigations requires new experimental equipment and new techniques of data analysis. The modern γ -ray spectrometers, like AGATA and GRETINA are now built of new-generation segmented germanium detectors. These most advanced detectors are able to reconstruct the trajectory of a γ -ray inside the detector. These are powerful detectors, but they need careful characterization, since their output signals are more complex. For instance for each γ -ray interaction that occurs in a segment of such a detector additional output signals (called proportional crosstalk), falsely appearing as an independent (often negative) energy depositions, are registered on the non-interacting segments. A failure to implement crosstalk correction results in incorrectly measured energies on the segments for two- and higher-fold events. It affects all experiments which rely on the recorded segment energies. Furthermore incorrectly recorded energies on the segments cause a failure to reconstruct the γ -ray trajectories using Compton scattering analysis. The proportional crosstalk for the iThemba LABS segmented clover was measured and a crosstalk correction was successfully implemented. The measured crosstalk-corrected energies show good agreement with the true γ -ray energies independent on the number of hit segments and an improved energy resolution for the segment sum energy was obtained. (paper)

Permutohedral Lattice CNNs

OpenAIRE

Kiefel, Martin; Jampani, Varun; Gehler, Peter V.

2014-01-01

This paper presents a convolutional layer that is able to process sparse input features. As an example, for image recognition problems this allows an efficient filtering of signals that do not lie on a dense grid (like pixel position), but of more general features (such as color values). The presented algorithm makes use of the permutohedral lattice data structure. The permutohedral lattice was introduced to efficiently implement a bilateral filter, a commonly used image processing operation....

Stability of mutualisms in a lattice gas system of two species

Directory of Open Access Journals (Sweden)

Yuanshi Wang

2015-01-01

Full Text Available This article considers mutualisms in a lattice gas system of two species. The species are mutualistic since each one can provide resources to the other. They are also competitive since they compete for empty sites on the same lattice. The mutualisms are assumed to have a saturated response, and the intraspecific competition is considered because of self-limitation. The mutualism system is characterized by differential equations, which are derived from reactions on lattice and are extension of a previous model. Global stability analysis demonstrates that (i When neither species can survive alone, they can coexist if mutualisms between them are strong and population densities are large, which exhibits the Allee effect in obligate mutualism; (ii When one species can survive alone but the other cannot, the latter one will survive if the mutualistic effect from the former is strong. Even if the effect is intermediate, the latter species can survive by strengthening its mutualistic effect on the former and enhancing its population density; (iii When either species can survive alone, a weak mutualism will lead to extinction of one species. When in coexistence, intermediate strength of mutualism is shown to be beneficial under certain parameter range, while over- or under- mutualism is not good. Furthermore, extremely strong/weak mutualism is exhibited to result in extinction of one/both species. While seven typical dynamics are displayed by numerical simulation in a previous work, they are proved in this work and the eighth one is exhibited. Numerical simul ations validate and extend our conclusions.

Interactions of Eu(III) with biogenic CaCO{sub 3} studied with TRLFS

Energy Technology Data Exchange (ETDEWEB)

Johnstone, Erik V.; Schmidt, Moritz [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Div. Surface Processes; Cherkouk, Andrea [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Div. Biogeochemistry

2016-07-01

The interactions of Eu(III) with CaCO{sub 3} arising from biogenic origin was investigated by Time-Resolved Laser-Induced Fluorescence Spectroscopy (TRLFS). Biologically-induced precipitation via ureolysis was studied with the bacteria Sporosarcina pasteurii in the presence of Eu(III). Biomineralization occurred forming mixed phases of vaterite and calcite after one day that transformed over two weeks to pure calcite. Eu(III) was quantitatively removed from solution during mineral formation. TRLFS results show that after one day the Eu{sup 3+} is located in the vaterite phase. After one week, the Eu{sup 3+} was found primarily in the vaterite, despite calcite now being the predominant mineral, and a transition species was also formed. In the calcite two incorporated Eu{sup 3+} species were present: one substitutes at the Ca{sup 2+} site in the crystal lattice and the other is speculated to be associated with the organicmineral matrix.

On the hierarchical lattices approximation of Bravais lattices: Specific heat and correlation length

International Nuclear Information System (INIS)

Tsallis, C.

1984-01-01

Certain types of real-space renormalization groups (which essentially approximate Bravais lattices through hierarchical ones) do not preserve standard thermodynamic convexity properties. It is pointed out that this serious defect is not intrinsic to any real-space renormalization. It can be avoided if form-invariance (under uniform translation of the energy scale) of the equation connecting the Bravais lattice (which is intended to study) to the hierarchical one (which approximates it) is demanded. In addition to that expressions for the critical exponentes ν and α corresponding to hierarchical lattices are analysed; these are consistent with Melrose recent analysis of the fractal intrinsic dimensionality. (Author) [pt

Use of some inorganic and organic compounds as decontaminants for cobalt-60 and caesium-134 by clover plant grown on Inshas sandy soil

Energy Technology Data Exchange (ETDEWEB)

Abdel Sabour, M.F.; El-Naggar, H.A.; Soliman, S.M. (Atomic Energy Establishment, Cairo (Egypt). Nuclear Chemistry Dept.)

1991-01-01

Outdoor lysimeter experiments were carried out to elucidate the effect of 4 inorganic and 3 organic salts on {sup 60}Co and {sup 134}Cs uptake and dry matter yield of three cuts of clover in the soils of Inshas. A new concept was proposed for assessing the difference in capacity of soil to supply radionuclides to plants as affected by applied inorganic or organic compounds. A relation of plant tissue radionuclide content with time can be expressed in an exponential equation with corresponding regression coefficients. When the same plant species is grown on the same soil differing only in the applied compounds (e.g. Fe-EDDHA, Fe-DTPA, Fe-OAC, Fe(COO){sub 2}, Al(OH){sub 3}, Ca(H{sub 2}PO{sub 4}){sub 2}, Fe{sub 2}O{sub 3}) the derived equation will change. Differences of either Co or Cs accumulation with time between control and any other treatment were evaluated. The data also show that Fe-DTPA is preferred for {sup 60}Co as enhancing compound for plant uptake (for decontamination use), compared with other applied salts, on the other hand, any tested salts did not significantly effect {sup 134}Cs taken by clover. It was also found that more than 70% of the total cobalt uptake was accumulated in the roots which indicate that Co is less mobile in plants than Cs. (orig.).

Use of some inorganic and organic compounds as decontaminants for cobalt-60 and caesium-134 by clover plant grown on Inshas sandy soil

International Nuclear Information System (INIS)

Abdel Sabour, M.F.; El-Naggar, H.A.; Soliman, S.M.

1991-01-01

Outdoor lysimeter experiments were carried out to elucidate the effect of 4 inorganic and 3 organic salts on 60 Co and 134 Cs uptake and dry matter yield of three cuts of clover in the soils of Inshas. A new concept was proposed for assessing the difference in capacity of soil to supply radionuclides to plants as affected by applied inorganic or organic compounds. A relation of plant tissue radionuclide content with time can be expressed in an exponential equation with corresponding regression coefficients. When the same plant species is grown on the same soil differing only in the applied compounds (e.g. Fe-EDDHA, Fe-DTPA, Fe-OAC, Fe(COO) 2 , Al(OH) 3 , Ca(H 2 PO 4 ) 2 , Fe 2 O 3 ) the derived equation will change. Differences of either Co or Cs accumulation with time between control and any other treatment were evaluated. The data also show that Fe-DTPA is preferred for 60 Co as enhancing compound for plant uptake (for decontamination use), compared with other applied salts, on the other hand, any tested salts did not significantly effect 134 Cs taken by clover. It was also found that more than 70% of the total cobalt uptake was accumulated in the roots which indicate that Co is less mobile in plants than Cs. (orig.) [de

Aliasing modes in the lattice Schwinger model

International Nuclear Information System (INIS)

Campos, Rafael G.; Tututi, Eduardo S.

2007-01-01

We study the Schwinger model on a lattice consisting of zeros of the Hermite polynomials that incorporates a lattice derivative and a discrete Fourier transform with many properties. Such a lattice produces a Klein-Gordon equation for the boson field and the exact value of the mass in the asymptotic limit if the boundaries are not taken into account. On the contrary, if the lattice is considered with boundaries new modes appear due to aliasing effects. In the continuum limit, however, this lattice yields also a Klein-Gordon equation with a reduced mass

Reaction of cocksfoot (Dactylis glomerata L. in grass-clover mixture on N fertilization and grazing

Directory of Open Access Journals (Sweden)

Marcela Andreata-Koren

2009-09-01

Full Text Available Grazing is the most common way of using a hill and mountain areas because of their specific agro-ecological conditions. Cocksfoot is a grass with high productivity and quality, and it is very good for sowing in the sward for grazing. Because of its good adaptability to different growing conditions, especially in very dry and cold areas, it is excellent in relation to some other good grasses, which can not be raised in such areas. The aim of the experiment was to determine effect of N application (0-N0 and 150 kg ha-1 year-1-N150 and rotational grazing by cattle (C and sheep (S, and their interaction on the cocksfoot sown in a mixture of smooth-stalked meadow grass (Poa pratensis L. and white clover (Trifolium repens L. in hill mountain areas. In a three-year average, the application of 150 kg ha-1 N had significant impact on cocksfoot population density (number of tillers m-2, and it was 51.4 % higher than the recorded one before grazing (P<0.05 and 42.2 % higher after grazing (P<0.01 in comparison to N0. The application of 150 kg ha-1 N resulted in significantly higher cocksfoot dry matter (DM yield for 38.6 % (P<0.01 and 15.3 % higher cocksfoot share in the total mixture in relation to N0 (P<0.01. Grazing management and grazing management interaction with N rate did not significantly affect the population density of individual years. However, in the three-year average, grazing management significantly affected cocksfoot DM (P<0.01 and its percentage in the total DM mixture (P<0.01. Cattle grazing resulted in 9.9 % higher cocksfoot DM yield and 15.2 % higher cocksfoot percentage in pasture. Interaction of grazing management and N-level had significant influence on the percentage of cocksfoot DM in grass-clover mixture. On cattle grazed areas fertilized with 150 kg ha-1 N, the percentage of cocksfoot DM was the highest (74. 07%, while the lowest percentage of cocksfoot DM was recorded on the sheep grazed areas without N (55.12%.

Manganese(III) Formate: A Three-Dimensional Framework That Traps Carbon Dioxide Molecules.

Science.gov (United States)

Cornia, Andrea; Caneschi, Andrea; Dapporto, Paolo; Fabretti, Antonio C; Gatteschi, Dante; Malavasi, Wanda; Sangregorio, Claudio; Sessoli, Roberta

1999-06-14

Carbon dioxide, formic acid, and water molecules are trapped in the crystal lattice of manganese(III) formate (see 1), which was obtained by reducing permanganate with formic acid. Each CO 2 guest molecule exhibits four C-H⋅⋅⋅O-C-O interactions with the three-dimensional host framework of Mn(HCOO) 3 units. Compound 1 undergoes an antiferromagnetic phase transition at 27 K. © 1999 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.

Racetrack lattices for the TRIUMF KAON factory

International Nuclear Information System (INIS)

Servranckx, R.V.; Wienands, U.; Craddock, M.K.; Rees, G.H.

1989-03-01

Separated-function racetrack lattices have been developed for the KAON Factory accelerators that have more flexibility than the old circular lattices. Straight sections with zero dispersion are provided for rf cavities and fast injection and extraction, and with controlled dispersion for H - injection and slow extraction. In addition the new lattices have fewer depolarizing resonances than the old circular lattices

Localized structures in Kagome lattices

Energy Technology Data Exchange (ETDEWEB)

Saxena, Avadh B [Los Alamos National Laboratory; Bishop, Alan R [Los Alamos National Laboratory; Law, K J H [UNIV OF MASSACHUSETTS; Kevrekidis, P G [UNIV OF MASSACHUSETTS

2009-01-01

We investigate the existence and stability of gap vortices and multi-pole gap solitons in a Kagome lattice with a defocusing nonlinearity both in a discrete case and in a continuum one with periodic external modulation. In particular, predictions are made based on expansion around a simple and analytically tractable anti-continuum (zero coupling) limit. These predictions are then confirmed for a continuum model of an optically-induced Kagome lattice in a photorefractive crystal obtained by a continuous transformation of a honeycomb lattice.

Lattice-Like Total Perfect Codes

Directory of Open Access Journals (Sweden)

Araujo Carlos

2014-02-01

Full Text Available A contribution is made to the classification of lattice-like total perfect codes in integer lattices Λn via pairs (G, Φ formed by abelian groups G and homomorphisms Φ: Zn → G. A conjecture is posed that the cited contribution covers all possible cases. A related conjecture on the unfinished work on open problems on lattice-like perfect dominating sets in Λn with induced components that are parallel paths of length > 1 is posed as well.

Lattice gauge theories

International Nuclear Information System (INIS)

Petronzio, R.

1992-01-01

Lattice gauge theories are about fifteen years old and I will report on the present status of the field without making the elementary introduction that can be found in the proceedings of the last two conferences. The talk covers briefly the following subjects: the determination of α s , the status of spectroscopy, heavy quark physics and in particular the calculation of their hadronic weak matrix elements, high temperature QCD, non perturbative Higgs bounds, chiral theories on the lattice and induced theories

Program LATTICE for Calculation of Parameters of Targets with Heterogeneous (Lattice) Structure

CERN Document Server

Bznuni, S A; Soloviev, A G; Sosnin, A N

2002-01-01

Program LATTICE, with which help it is possible to describe lattice structure for the program complex CASCAD, is created in the C++ language. It is shown that for model-based electronuclear system on a basis of molten salt reactor with graphite moderator at transition from homogeneous structure to heterogeneous at preservation of a chemical compound there is a growth of k_{eff} by approximately 6 %.

Unquenched lattice upsilon spectroscopy

International Nuclear Information System (INIS)

Marcantonio, L.M.

2001-03-01

A non-relativistic effective theory of QCD (NRQCD) is used in calculations of the upsilon spectrum. Simultaneous multi-correlation fitting routines are used to yield lattice channel energies and amplitudes. The lattice configurations used were both dynamical, with two flavours of sea quarks included in the action; and quenched, with no sea quarks. These configurations were generated by the UKQCD collaboration. The dynamical configurations used were ''matched'', having the same lattice spacing, but differing in the sea quark mass. Thus, it was possible to analyse trends of observables with sea quark mass, in the certainty that the trend isn't partially due to varying lattice spacing. The lattice spacing used for spectroscopy was derived from the lattice 1 1 P 1 - 1 3 S 1 splitting. On each set of configurations two lattice bare b quark masses were used, giving kinetic masses bracketing the physical Υ mass. The only quantity showing a strong dependence on these masses was the hyperfine splitting, so it was interpolated to the real Υ mass. The radial and orbital splittings gave good agreement with experiment. The hyperfine splitting results showed a clear signal for unquenching and the dynamical hyperfine splitting results were extrapolated to a physical sea quark mass. This result, combined with the quenched result yielded a value for the hyperfine splitting at n f = 3, predicting an η b mass of 9.517(4) GeV. The NRQCD technique for obtaining a value of the strong coupling constant in the M-barS-bar scheme was followed. Using quenched and dynamical results a value was extrapolated to n f = 3. Employing a three loop beta function to run the coupling, with suitable matching conditions at heavy quark thresholds, the final result was obtained for n f = 5 at a scale equal to the Z boson mass. This result was α(5)/MS(Mz)=0.110(4). Two methods for finding the mass of the b quark in the MS scheme were employed. The results of both methods agree within error but the

Light-cone distribution amplitudes of the baryon octet

International Nuclear Information System (INIS)

Bali, Gunnar S.; Braun, Vladimir M.; Göckeler, Meinulf; Gruber, Michael; Hutzler, Fabian; Schäfer, Andreas; Schiel, Rainer W.; Simeth, Jakob; Söldner, Wolfgang; Sternbeck, Andre; Wein, Philipp

2016-01-01

We present results of the first ab initio lattice QCD calculation of the normalization constants and first moments of the leading twist distribution amplitudes of the full baryon octet, corresponding to the small transverse distance limit of the associated S-wave light-cone wave functions. The P-wave (higher twist) normalization constants are evaluated as well. The calculation is done using N_f=2+1 flavors of dynamical (clover) fermions on lattices of different volumes and pion masses down to 222 MeV. Significant SU(3) flavor symmetry violation effects in the shape of the distribution amplitudes are observed.

Light-cone distribution amplitudes of the baryon octet

Energy Technology Data Exchange (ETDEWEB)

Bali, Gunnar S. [Institut für Theoretische Physik, Universität Regensburg,Universitätsstraße 31, D-93040 Regensburg (Germany); Department of Theoretical Physics, Tata Institute of Fundamental Research,Homi Bhabha Road, Mumbai 400005 (India); Braun, Vladimir M.; Göckeler, Meinulf; Gruber, Michael; Hutzler, Fabian; Schäfer, Andreas; Schiel, Rainer W.; Simeth, Jakob; Söldner, Wolfgang [Institut für Theoretische Physik, Universität Regensburg,Universitätsstraße 31, D-93040 Regensburg (Germany); Sternbeck, Andre [Theoretisch-Physikalisches Institut, Friedrich-Schiller-Universität Jena,Max-Wien-Platz 1, D-07743 Jena (Germany); Wein, Philipp [Institut für Theoretische Physik, Universität Regensburg,Universitätsstraße 31, D-93040 Regensburg (Germany)

2016-02-10

We present results of the first ab initio lattice QCD calculation of the normalization constants and first moments of the leading twist distribution amplitudes of the full baryon octet, corresponding to the small transverse distance limit of the associated S-wave light-cone wave functions. The P-wave (higher twist) normalization constants are evaluated as well. The calculation is done using N{sub f}=2+1 flavors of dynamical (clover) fermions on lattices of different volumes and pion masses down to 222 MeV. Significant SU(3) flavor symmetry violation effects in the shape of the distribution amplitudes are observed.

Spatiotemporal complexity in coupled map lattices

International Nuclear Information System (INIS)

Kaneko, Kunihiko

1986-01-01

Some spatiotemporal patterns of couple map lattices are presented. The chaotic kink-like motions are shown for the phase motion of the coupled circle lattices. An extension of the couple map lattice approach to Hamiltonian dynamics is briefly reported. An attempt to characterize the high-dimensional attractor by the extension of the correlation dimension is discussed. (author)

Gauge theories on a small lattice

International Nuclear Information System (INIS)

Robson, D.; Webber, D.M.

1980-01-01

We present exact solutions to U(1), SU(2), and SU(3) lattice gauge theories on a Kogut-Susskind lattice consisting of a single plaquette. We demonstrate precise equivalence between the U(1) theory and the harmonic oscillator on an infinite one-dimensional lattice, and between the SU(N) theory and an N-fermion Schroedinger equation. (orig.)

Lattice Methods for Quantum Chromodynamics

CERN Document Server

DeGrand, Thomas

2006-01-01

Numerical simulation of lattice-regulated QCD has become an important source of information about strong interactions. In the last few years there has been an explosion of techniques for performing ever more accurate studies on the properties of strongly interacting particles. Lattice predictions directly impact many areas of particle and nuclear physics theory and phenomenology. This book provides a thorough introduction to the specialized techniques needed to carry out numerical simulations of QCD: a description of lattice discretizations of fermions and gauge fields, methods for actually do

Lattice degeneration of the retina and retinal detachment.

Science.gov (United States)

Semes, L P

1992-01-01

Lattice retinal degeneration is considered the most significant peripheral retinal disorder potentially predisposing to retinal breaks and retinal detachment. Lattice degeneration affects the vitreous and inner retinal layers with secondary changes as deep as the retinal pigment epithelium and perhaps the choriocapillaris. Variations in clinical appearance are the rule; geographically, lattice lesions favor the vertical meridians between the equator and the ora serrata. Lattice degeneration begins early in life and has been reported in sequential generations of the same family. Along with its customary bilateral occurrence, lattice shares other characteristics of a dystrophy. The association between the vitreous and retina in lattice lesions may be responsible for the majority of lattice-induced retinal detachments. The tumultuous event of posterior vitreous separation in the presence of abnormally strong vitreoretinal adherence is the trigger for a retinal tear that, in turn, may lead to retinal detachment. Although retinal holes in young patients with lattice degeneration may play a role in the evolution of retinal detachment, the clinical course of lattice degeneration seems to be one of dormancy rather than of progressive change. This discussion outlines the pathophysiology of lattice retinal degeneration and the relationship of pathophysiology to clinical presentation. The epidemiology of lattice degeneration is summarized, as are the possible precursors to retinal detachment. A clinical characterization of the natural history of lattice degeneration is offered, and interventions for complications are described. To conclude, management strategies from a primary-care standpoint are reviewed.

Lattice site occupation of insoluble impurity atoms in aluminium after implantation and irradiation

International Nuclear Information System (INIS)

Kloska, M.K.

1987-03-01

Several elements, whose atoms are oversized and insoluble in aluminium, were implanted in aluminium single crystals at different temperatures. The substitutional fraction and the lattice site location were determined using the ion-channeling technique. The substitutional fractions obtained by in situ analyses are strongly dependent on the implantation temperature. At implantation and analysis temperatures below the temperature of stage III the substitutional fraction is significant larger than at temperatures above. With increasing heat of solution the substitutional fraction decreases for all implantation temperatures. The nonsubstitutional component consists of impurity atom-vacancy complexes. These complexes are formed in the cooling phase of the cascade. At temperatures above the temperature of stage III additional free mobile vacancies were captured by the impurity atoms. The capture radius is correlated with the heat of solution and the size mismatch energy. The results constitute for the first time an experimental confirmation of molecular dynamics calculations of cascade evolution. (orig./BHO)

Comparing the results of lattice and off-lattice simulations for the melt of nonconcatenated rings

International Nuclear Information System (INIS)

Halverson, Jonathan D; Kremer, Kurt; Grosberg, Alexander Y

2013-01-01

To study the conformational properties of unknotted and nonconcatenated ring polymers in the melt, we present a detailed qualitative and quantitative comparison of simulation data obtained by molecular dynamics simulation using an off-lattice bead-spring model and by Monte Carlo simulation using a lattice model. We observe excellent, and sometimes even unexpectedly good, agreement between the off-lattice and lattice results for many quantities measured including the gyration radii of the ring polymers, gyration radii of their subchains, contact probabilities, surface characteristics, number of contacts between subchains, and the static structure factors of the rings and their subchains. These results are, in part, put in contrast to Moore curves, and the open, linear polymer counterparts. While our analysis is extensive, our understanding of the ring melt conformations is still rather preliminary. (paper)

Discrete Lattice effect of various forcing methods of body force on immersed Boundary-Lattice Boltzmann method

Energy Technology Data Exchange (ETDEWEB)

Son, Sung Wan; Ha, Man Yeong; Yoon, Hyun Sik [Pusan National University, Busan (Korea, Republic of); Jeong, Hae Kwon [POSCO, Pohang (Korea, Republic of); Balachandar, S. [University of Florida, Florida (United States)

2013-02-15

We investigate the discrete lattice effect of various forcing methods in the lattice Boltzmann method (LBM) to include the body force obtained from the immersed boundary method (IBM). In the immersed boundary lattice Boltzmann method (IB-LBM), the LBM needs a forcing method to involve the body force on a forcing point near the immersed boundary that is calculated by IBM. The proper forcing method in LBM is derived to include the body force, which appears to resolve problems such as multiphase flow, non-ideal gas behavior, etc. Many researchers have adopted different forcing methods in LBM to involve the body force from IBM, even when they solved similar problems. However, it is necessary to evaluate the discrete lattice effect, which originates from different forcing methods in LBM, to include the effect of the body force from IBM on the results. Consequently, in this study, a rigorous analysis of the discrete lattice effect for different forcing methods in IB-LBM is performed by solving various problems.

Discrete Lattice effect of various forcing methods of body force on immersed Boundary-Lattice Boltzmann method

International Nuclear Information System (INIS)

Son, Sung Wan; Ha, Man Yeong; Yoon, Hyun Sik; Jeong, Hae Kwon; Balachandar, S.

2013-01-01

We investigate the discrete lattice effect of various forcing methods in the lattice Boltzmann method (LBM) to include the body force obtained from the immersed boundary method (IBM). In the immersed boundary lattice Boltzmann method (IB-LBM), the LBM needs a forcing method to involve the body force on a forcing point near the immersed boundary that is calculated by IBM. The proper forcing method in LBM is derived to include the body force, which appears to resolve problems such as multiphase flow, non-ideal gas behavior, etc. Many researchers have adopted different forcing methods in LBM to involve the body force from IBM, even when they solved similar problems. However, it is necessary to evaluate the discrete lattice effect, which originates from different forcing methods in LBM, to include the effect of the body force from IBM on the results. Consequently, in this study, a rigorous analysis of the discrete lattice effect for different forcing methods in IB-LBM is performed by solving various problems.

EPRI-LATTICE: a multigroup neutron transport code for light water reactor lattice physics calculations

International Nuclear Information System (INIS)

Jones, D.B.

1986-01-01

EPRI-LATTICE is a multigroup neutron transport computer code for the analysis of light water reactor fuel assemblies. It can solve the two-dimensional neutron transport problem by two distinct methods: (a) the method of collision probabilities and (b) the method of discrete ordinates. The code was developed by S. Levy Inc. as an account of work sponsored by the Electric Power Research Institute (EPRI). The collision probabilities calculation in EPRI-LATTICE (L-CP) is based on the same methodology that exists in the lattice codes CPM-2 and EPRI-CPM. Certain extensions have been made to the data representations of the CPM programs to improve the overall accuracy of the calculation. The important extensions include unique representations of scattering matrices and fission fractions (chi) for each composition in the problem. A new capability specifically developed for the EPRI-LATTICE code is a discrete ordinates methodology. The discrete ordinates calculation in EPRI-LATTICE (L-SN) is based on the discrete S/sub n/ methodology that exists in the TWODANT program. In contrast to TWODANT, which utilizes synthetic diffusion acceleration and supports multiple geometries, only the transport equations are solved by L-SN and only the data representations for the two-dimensional geometry are treated

Electric Dipole Moment Results from lattice QCD

Science.gov (United States)

Dragos, Jack; Luu, Thomas; Shindler, Andrea; de Vries, Jordy

2018-03-01

We utilize the gradient flow to define and calculate electric dipole moments induced by the strong QCD θ-term and the dimension-6 Weinberg operator. The gradient flow is a promising tool to simplify the renormalization pattern of local operators. The results of the nucleon electric dipole moments are calculated on PACS-CS gauge fields (available from the ILDG) using Nf = 2+1, of discrete size 323×64 and spacing a ≃ 0.09 fm. These gauge fields use a renormalization-group improved gauge action and a nonperturbatively O(a) improved clover quark action at β = 1.90, with cSW = 1.715. The calculation is performed at pion masses of mπ ≃ 411, 701 MeV.

Commensurability effects in holographic homogeneous lattices

International Nuclear Information System (INIS)

Andrade, Tomas; Krikun, Alexander

2016-01-01

An interesting application of the gauge/gravity duality to condensed matter physics is the description of a lattice via breaking translational invariance on the gravity side. By making use of global symmetries, it is possible to do so without scarifying homogeneity of the pertinent bulk solutions, which we thus term as “homogeneous holographic lattices.' Due to their technical simplicity, these configurations have received a great deal of attention in the last few years and have been shown to correctly describe momentum relaxation and hence (finite) DC conductivities. However, it is not clear whether they are able to capture other lattice effects which are of interest in condensed matter. In this paper we investigate this question focusing our attention on the phenomenon of commensurability, which arises when the lattice scale is tuned to be equal to (an integer multiple of) another momentum scale in the system. We do so by studying the formation of spatially modulated phases in various models of homogeneous holographic lattices. Our results indicate that the onset of the instability is controlled by the near horizon geometry, which for insulating solutions does carry information about the lattice. However, we observe no sharp connection between the characteristic momentum of the broken phase and the lattice pitch, which calls into question the applicability of these models to the physics of commensurability.

Lattice QCD. A critical status report

Energy Technology Data Exchange (ETDEWEB)

Jansen, Karl

2008-10-15

The substantial progress that has been achieved in lattice QCD in the last years is pointed out. I compare the simulation cost and systematic effects of several lattice QCD formulations and discuss a number of topics such as lattice spacing scaling, applications of chiral perturbation theory, non-perturbative renormalization and finite volume effects. Additionally, the importance of demonstrating universality is emphasized. (orig.)

Lattice QCD. A critical status report

International Nuclear Information System (INIS)

Jansen, Karl

2008-10-01

The substantial progress that has been achieved in lattice QCD in the last years is pointed out. I compare the simulation cost and systematic effects of several lattice QCD formulations and discuss a number of topics such as lattice spacing scaling, applications of chiral perturbation theory, non-perturbative renormalization and finite volume effects. Additionally, the importance of demonstrating universality is emphasized. (orig.)

Nitrato-complexes of Y(III), La(III), Ce(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III), Dy(III) and Ho(III) with 2-(2'-pyridyl) benzimidazole

Energy Technology Data Exchange (ETDEWEB)

Mishra, A; Singh, M P; Singh, V K

1982-05-01

The nitrato-complexes, (Y(PyBzH)/sub 2/(NO/sub 3/)/sub 2/)NO/sub 3/.H/sub 2/O and Nd, Sm, Gd, Tb, Dy, Ho ; n=1-3, m=0-0.5 ; PyBzh=2-(2 -pyridyl)benzimidazole) are formed on interaction of the ligand with metal nitrates in ethanol. The electrical conductance values (116-129 ohm/sup -1/cm/sup 2/mol/sup -1/) suggest 1:1 electrolyte-nature of the complexes. Magnetic moment values of Ce(2.53 B.M.), Pr(3.62 B.M.), Nd(3.52 B.M.), Sm(1.70 B.M.), Gd(8.06 B.M.), Tb(9.44 B.M.), Dy(10.56 B.M.) and Ho(10.51 B.M.) in the complexes confirm the positive state of the metals. Infrared evidences are obtained for the existance of both coordinated (C/sub 2/v) and uncoordinated (D/sub 3/h) nitrate groups. Electronic absorption spectra of Pr(III)-, Nd(III)-, Sm(III)-, Tb(III)-, Dy(III)- and Ho(III)-complexes have been analysed in the light of LSJ terms.

Nitrato-complexes of Y(III), La(III), Ce(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III), Dy(III) and Ho(III) with 2-(2'-pyridyl) benzimidazole

International Nuclear Information System (INIS)

Mishra, A.; Singh, M.P.; Singh, V.K.

1982-01-01

The nitrato-complexes, [Y(PyBzH) 2 (NO 3 ) 2 ]NO 3 .H 2 O and Nd, Sm, Gd, Tb, Dy, Ho ; n=1-3, m=0-0.5 ; PyBzh=2-(2 -pyridyl)benzimidazole] are formed on interaction of the ligand with metal nitrates in ethanol. The electrical conductance values (116-129 ohm -1 cm 2 mol -1 ) suggest 1:1 electrolyte-nature of the complexes. Magnetic moment values of Ce(2.53 B.M.), Pr(3.62 B.M.), Nd(3.52 B.M.), Sm(1.70 B.M.), Gd(8.06 B.M.), Tb(9.44 B.M.), Dy(10.56 B.M.) and Ho(10.51 B.M.) in the complexes confirm the terpositive state of the metals. Infrared evidences are obtained for the existance of both coordinated (C 2 v) and uncoordinated (D 3 h) nitrate groups. Electronic absorption spectra of Pr(III)-, Nd(III)-, Sm(III)-, Tb(III)-, Dy(III)- and Ho(III)-complexes have been analysed in the light of LSJ terms. (author)

More on random-lattice fermions

International Nuclear Information System (INIS)

Kieu, T.D.; Institute for Advanced Study, Princeton, NJ; Markham, J.F.; Paranavitane, C.B.

1995-01-01

The lattice fermion determinants, in a given background gauge field, are evaluated for two different kinds of random lattices and compared to those of naive and wilson fermions in the continuum limit. While the fermion doubling is confirmed on one kind of lattices, there is positive evidence that it may be absent for the other, at least for vector interactions in two dimensions. Combined with previous studies, arbitrary randomness by itself is shown to be not a sufficient condition to remove the fermion doublers. 8 refs., 3 figs

Lattice sums then and now

CERN Document Server

Borwein, J M; McPhedran, R C

2013-01-01

The study of lattice sums began when early investigators wanted to go from mechanical properties of crystals to the properties of the atoms and ions from which they were built (the literature of Madelung's constant). A parallel literature was built around the optical properties of regular lattices of atoms (initiated by Lord Rayleigh, Lorentz and Lorenz). For over a century many famous scientists and mathematicians have delved into the properties of lattices, sometimes unwittingly duplicating the work of their predecessors. Here, at last, is a comprehensive overview of the substantial body of

Exogenous Application of GABA Improves PEG-Induced Drought Tolerance Positively Associated with GABA-Shunt, Polyamines, and Proline Metabolism in White Clover.

Science.gov (United States)

Yong, Bin; Xie, Huan; Li, Zhou; Li, Ya-Ping; Zhang, Yan; Nie, Gang; Zhang, Xin-Quan; Ma, Xiao; Huang, Lin-Kai; Yan, Yan-Hong; Peng, Yan

2017-01-01

In order to investigate the physiological effects of exogenous γ-aminobutyric acid (GABA) on drought tolerance in white clover (Trifolium repens), GABA shunt, polyamines (PAs), and proline (Pro) metabolism were examined after plants pretreated with or without GABA (8 mM) and then exposed to water or 15% PEG-induced drought stress in growth chamber. In this study, exogenous application of GABA effectively alleviated drought-induced damage in leaves, as reflected by significantly higher relative water content, lower electrolyte leakage, lipid peroxidation, and leaf wilt. Exogenous GABA further promoted drought-induced increases in GABA transaminase and alpha ketone glutarate dehydrogenase activities, but inhibited glutamate decarboxylase activity under both control and drought conditions, resulting in an increase in endogenous glutamate (Glu) and GABA content. Besides, exogenous GABA could well accelerated PAs synthesis and suppressed PAs catabolism, which lead to the extremely enhanced different types of PAs content (free Put and Spd, insoluble bound Spd and Spm, soluble conjugated Spd and Spm, and total Put, Spd and Spm) under drought stress. In addition, exogenous GABA application further activated drought-induced Δ 1 -pyrroline-5-carboxylate synthetase and proline dehydrogenase activities, but suppressed drought-facilitated ornithine -δ-amino transferase activities, leading to a higher Pro accumulation and metabolism in GABA-pretreated plants in the middle and last period of drought. The results suggested that increased endogenous GABA by exogenous GABA treatment could improve drought tolerance of white clover associated with a positive regulation in the GABA-shunt, PAs and Pro metabolism.

Red clover-derived isoflavones and mammographic breast density: a double-blind, randomized, placebo-controlled trial [ISRCTN42940165

International Nuclear Information System (INIS)

Atkinson, Charlotte; Warren, Ruth ML; Sala, Evis; Dowsett, Mitch; Dunning, Alison M; Healey, Catherine S; Runswick, Shirley; Day, Nicholas E; Bingham, Sheila A

2004-01-01

Isoflavones are hypothesized to protect against breast cancer, but it is not clear whether they act as oestrogens or anti-oestrogens in breast tissue. Our aim was to determine the effects of taking a red clover-derived isoflavone supplement daily for 1 year on mammographic breast density. Effects on oestradiol, follicle-stimulating hormone (FSH), luteinizing hormone (LH), lymphocyte tyrosine kinase activity and menopausal symptoms were also assessed. A total of 205 women (age range 49–65 years) with Wolfe P2 or DY mammographic breast patterns were randomly assigned to receive either a red clover-derived isoflavone tablet (26 mg biochanin A, 16 mg formononetin, 1 mg genistein and 0.5 mg daidzein) or placebo. Change in mammographic breast density, serum oestradiol, FSH, LH, menopausal symptoms and lymphocyte tyrosine kinase activity from baseline to 12 months were assessed. A total of 177 women completed the trial. Mammographic breast density decreased in both groups but the difference between the treatment and placebo was not statistically significant. There was a significant interaction between treatment group and oestrogen receptor (ESR1) PvuII polymorphism for the change in estimated percentage breast density (mean ± standard deviation): TT isoflavone 1.4 ± 12.3% and TT placebo -9.6 ± 14.2%; CT isoflavone -5.2 ± 12.0% and CT placebo -2.8 ± 10.3%; and CC isoflavone -3.4 ± 9.7% and CC placebo -1.1 ± 9.5%. There were no statistically significant treatment effects on oestradiol, FSH, or LH (assessed only in postmenopausal women), or on lymphocyte tyrosine kinase activity. Baseline levels of menopausal symptoms were low, and there were no statistically significant treatment effects on frequency of hot flushes or other menopausal symptoms. In contrast to studies showing that conventional hormone replacement therapies increase mammographic breast density, the isoflavone supplement did not increase mammographic breast density in this population of women

LATTICE/hor ellipsis/a beam transport program

International Nuclear Information System (INIS)

Staples, J.

1987-06-01

LATTICE is a computer program that calculates the first order characteristics of synchrotrons and beam transport systems. The program uses matrix algebra to calculate the propagation of the betatron (Twiss) parameters along a beam line. The program draws on ideas from several older programs, notably Transport and Synch, adds many new ones and incorporates them into an interactive, user-friendly program. LATTICE will calculate the matched functions of a synchrotron lattice and display them in a number of ways, including a high resolution Tektronix graphics display. An optimizer is included to adjust selected element parameters so the beam meets a set of constraints. LATTICE is a first order program, but the effect of sextupoles on the chromaticity of a synchrotron lattice is included, and the optimizer will set the sextupole strengths for zero chromaticity. The program will also calculate the characteristics of beam transport systems. In this mode, the beam parameters, defined at the start of the transport line, are propagated through to the end. LATTICE has two distinct modes: the lattice mode which finds the matched functions of a synchrotron, and the transport mode which propagates a predefined beam through a beam line. However, each mode can be used for either type of problem: the transport mode may be used to calculate an insertion for a synchrotron lattice, and the lattice mode may be used to calculate the characteristics of a long periodic beam transport system

Elemental analysis and nutritional value of edible Trifolium (clover) species.

Science.gov (United States)

Gounden, Thaveshan; Moodley, Roshila; Jonnalagadda, Sreekantha B

2018-04-30

Trifolium species, commonly known as clover species, have a cosmopolitan distribution and, as such, are used in many different traditional systems of medicine and consumed by many communities all over the world. In this study, the elemental distribution and nutritional value of five edible Trifolium species, namely, Trifolium africanum, Trifolium burchellianum, Trifolium repens, Trifolium dubium and Trifolium pratense were investigated to evaluate the potential of these plant species to alleviate malnutrition, thereby contributing toward the fight against food insecurity. Trifolium species were found to be a rich alternate source of essential nutrients with concentrations of elements being in decreasing order of Ca > Mg > Fe > Mn > Zn > Se > Cu > Cr > Pb > Ni > Co > Cd > As and with adequate levels of lipids (4.2 to 8.6%), proteins (35.1 to 45.4%) and carbohydrates (26.7 to 47.0%). Trifolium species were found to be rich in Se (contributing greater than 516% toward its RDA) with T. dubium having a concentration of 0.53 mg 10 g -1 , dry mass, which is higher than Brazil nuts. T. pratense was found to be the most suitable species for human consumption due to it having low levels of toxic metals (As, Cd and Pb) while being rich in macro- and micro-elements, especially Fe (7.84 mg 10 g -1 , dry mass) and Se (0.36 mg 10 g -1 , dry mass).

Comparison of breeding methods for forage yield in red clover

Directory of Open Access Journals (Sweden)

Libor Jalůvka

2009-01-01

Full Text Available Three methods of red clover (Trifolium pratense L. breeding for forage yield in two harvest years on locations in Bredelokke (Denmark, Hladké Životice (Czech Republic and Les Alleuds (France were compared. Three types of 46 candivars1, developed by A recurrent selection in subsequent generations (37 candivars, divided into early and late group, B polycross progenies (4 candivars and C ge­no-phe­no­ty­pic selection (5 candivars were compared. The trials were sown in 2005 and cut three times in 2006 and 2007; their evaluation is based primarily on total yield of dry matter. The candivars developed by polycross and geno-phenotypic selections gave significantly higher yields than candivars from the recurrent selection. However, the candivars developed by the methods B and C did not differ significantly. The candivars developed by these progressive methods were suitable for higher yielding and drier environment in Hladké Životice (where was the highest yield level even if averaged annual precipitation were lower by 73 and 113 mm in comparison to other locations, respectively; here was ave­ra­ge yield higher by 19 and 13% for B and C in comparison to A method. Highly significant interaction of the candivars with locations was found. It can be concluded that varieties specifically aimed to different locations by the methods B and C should be bred; also the parental entries should be selected there.

Manipulation and quantification of microtubule lattice integrity

Directory of Open Access Journals (Sweden)

Taylor A. Reid

2017-08-01

Full Text Available Microtubules are structural polymers that participate in a wide range of cellular functions. The addition and loss of tubulin subunits allows the microtubule to grow and shorten, as well as to develop and repair defects and gaps in its cylindrical lattice. These lattice defects act to modulate the interactions of microtubules with molecular motors and other microtubule-associated proteins. Therefore, tools to control and measure microtubule lattice structure will be invaluable for developing a quantitative understanding of how the structural state of the microtubule lattice may regulate its interactions with other proteins. In this work, we manipulated the lattice integrity of in vitro microtubules to create pools of microtubules with common nucleotide states, but with variations in structural states. We then developed a series of novel semi-automated analysis tools for both fluorescence and electron microscopy experiments to quantify the type and severity of alterations in microtubule lattice integrity. These techniques will enable new investigations that explore the role of microtubule lattice structure in interactions with microtubule-associated proteins.

3D Metallic Lattices for Accelerator Applications

CERN Document Server

Shapiro, Michael A; Sirigiri, Jagadishwar R; Temkin, Richard J

2005-01-01

We present the results of research on 3D metallic lattices operating at microwave frequencies for application in (1) accelerator structures with higher order mode suppression, (2) Smith-Purcell radiation beam diagnostics, and (3) polaritonic materials for laser acceleration. Electromagnetic waves in a 3D simple cubic lattice formed by metal wires are calculated using HFSS. The bulk modes in the lattice are determined using single cell calculations with different phase advances in all three directions. The Brillouin diagram for the bulk modes is presented and indicates the absence of band gaps in simple lattices except the band below the cutoff. Lattices with thin wires as well as with thick wires have been analyzed. The Brillouin diagram also indicates the presence of low frequency 3D plasmon mode as well as the two degenerate photon modes analogous to those in a 2D lattice. Surface modes for a semi-infinite cubic lattice are modeled as a stack of cells with different phase advances in the two directions alon...

Strong dynamics and lattice gauge theory

Science.gov (United States)

Schaich, David

In this dissertation I use lattice gauge theory to study models of electroweak symmetry breaking that involve new strong dynamics. Electroweak symmetry breaking (EWSB) is the process by which elementary particles acquire mass. First proposed in the 1960s, this process has been clearly established by experiments, and can now be considered a law of nature. However, the physics underlying EWSB is still unknown, and understanding it remains a central challenge in particle physics today. A natural possibility is that EWSB is driven by the dynamics of some new, strongly-interacting force. Strong interactions invalidate the standard analytical approach of perturbation theory, making these models difficult to study. Lattice gauge theory is the premier method for obtaining quantitatively-reliable, nonperturbative predictions from strongly-interacting theories. In this approach, we replace spacetime by a regular, finite grid of discrete sites connected by links. The fields and interactions described by the theory are likewise discretized, and defined on the lattice so that we recover the original theory in continuous spacetime on an infinitely large lattice with sites infinitesimally close together. The finite number of degrees of freedom in the discretized system lets us simulate the lattice theory using high-performance computing. Lattice gauge theory has long been applied to quantum chromodynamics, the theory of strong nuclear interactions. Using lattice gauge theory to study dynamical EWSB, as I do in this dissertation, is a new and exciting application of these methods. Of particular interest is non-perturbative lattice calculation of the electroweak S parameter. Experimentally S ≈ -0.15(10), which tightly constrains dynamical EWSB. On the lattice, I extract S from the momentum-dependence of vector and axial-vector current correlators. I created and applied computer programs to calculate these correlators and analyze them to determine S. I also calculated the masses

Heavy water critical experiments on plutonium lattice

International Nuclear Information System (INIS)

Miyawaki, Yoshio; Shiba, Kiminori

1975-06-01

This report is the summary of physics study on plutonium lattice made in Heavy Water Critical Experiment Section of PNC. By using Deuterium Critical Assembly, physics study on plutonium lattice has been carried out since 1972. Experiments on following items were performed in a core having 22.5 cm square lattice pitch. (1) Material buckling (2) Lattice parameters (3) Local power distribution factor (4) Gross flux distribution in two region core (5) Control rod worth. Experimental results were compared with theoretical ones calculated by METHUSELAH II code. It is concluded from this study that calculation by METHUSELAH II code has acceptable accuracy in the prediction on plutonium lattice. (author)

Vitreous in lattice degeneration of retina.

Science.gov (United States)

Foos, R Y; Simons, K B

1984-05-01

A localized pocket of missing vitreous invariably overlies lattice degeneration of the retina. Subjects with lattice also have a higher rate of rhegmatogenous retinal detachment, which is usually a complication of retinal tears. The latter are in turn a result of alterations in the central vitreous--that is, synchysis senilis leading to posterior vitreous detachment. In order to determine if there is either an association or a deleterious interaction between the local and central lesions of the vitreous in eyes with lattice, a comparison was made in autopsy eyes with and without lattice the degree of synchysis and rate of vitreous detachment. Results show no association between the local and central vitreous lesions, indicating that a higher rate of vitreous detachment is not the basis for the higher rate of retinal detachment in eyes with lattice. Also, there was no suggestion of deleterious interaction between the local and central vitreous lesions, either through vitreodonesis as a basis for precocious vitreous detachment, or through a greater degree of synchysis as a basis for interconnection of local and central lacunae (which could extend the localized retinal detachment in eyes with holes in lattice degeneration).

END FIELD EFFECTS IN BEND ONLY COOLING LATTICES

International Nuclear Information System (INIS)

BEERG, J.S.; KIRK, H.; GARREN, A.

2003-01-01

Cooling lattices consisting only of bends (using either rotated pole faces or gradient dipoles to achieve focusing) often require large apertures and short magnets. One expects the effect of end fields to be significant in this case. In this paper we explore the effect of adding end fields to a working lattice design that originally lacked them. The paper describes the process of correcting the lattice design for the added end fields so as to maintain desirable lattice characteristics. It then compares the properties of the lattice with end fields relative to the lattice without them

On diffeomorphism invariance for lattice theories

International Nuclear Information System (INIS)

Corichi, A.; Zapata, J.

1997-01-01

We consider the role of the diffeomorphism constraint in the quantization of lattice formulations of diffeomorphism invariant theories of connections. It has been argued that in working with abstract lattices one automatically takes care of the diffeomorphism constraint in the quantum theory. We use two systems in order to show that imposing the diffeomorphism constraint is imperative to obtain a physically acceptable quantum theory. First, we consider 2+1 gravity where an exact lattice formulation is available. Next, general theories of connections for compact gauge groups are treated, where the quantum theories are known - for both the continuum and the lattice - and can be compared. (orig.)

Hexagonal perovskites with cationic vacancies. 3. Structure determination on compounds of type Ba/sub 2/Bsub(1/3)sup(III)vacantsub(2/3)Resup(VII)O/sub 6/

Energy Technology Data Exchange (ETDEWEB)

Kemmler-Sack, S; Wischert, W; Treiber, U [Tuebingen Univ. (Germany, F.R.). Inst. fuer Chemie

1978-09-01

Compounds of type Ba/sub 2/Bsub(1/3)sup(III)vacantsub(2/3)Resup(VII)O/sub 6/ with Bsup(III) = rare earth, Y, Sc. In belong to the group of hexagonal perovskite stacking polytypes. For Bsup(III) = Gd, Y structure determinations with powder data have been performed. The refined R' factors are 9.11% for Ba/sub 2/Gdsub(1/3)vacantsub(2/3)ReO/sub 6/ and 12.07% for Ba/sub 2/Ysub(1/3)vacantsub(2/3)ReO/sub 6/. The structure represents a rhombohedral 12 L type (space group R3m) with the sequence hhcchhcchhcc. The lattice contains groups of three octahedra connected by common faces which are linked together by a single octahedron via common vertices. In the block of three face-sharing octahedra the central octahedral lattice site is vacant and the two outer positions are occupied by the rhenium atoms. According to this distribution direct contact of occupied face-sharing octahedra is absent.

Exact Lattice Supersymmetry

Energy Technology Data Exchange (ETDEWEB)

Catterall, Simon; Kaplan, David B.; Unsal, Mithat

2009-03-31

We provide an introduction to recent lattice formulations of supersymmetric theories which are invariant under one or more real supersymmetries at nonzero lattice spacing. These include the especially interesting case of N = 4 SYM in four dimensions. We discuss approaches based both on twisted supersymmetry and orbifold-deconstruction techniques and show their equivalence in the case of gauge theories. The presence of an exact supersymmetry reduces and in some cases eliminates the need for fine tuning to achieve a continuum limit invariant under the full supersymmetry of the target theory. We discuss open problems.

Experimental generation of optical coherence lattices

Energy Technology Data Exchange (ETDEWEB)

Chen, Yahong; Cai, Yangjian, E-mail: serpo@dal.ca, E-mail: yangjiancai@suda.edu.cn [College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou 215006 (China); Ponomarenko, Sergey A., E-mail: serpo@dal.ca, E-mail: yangjiancai@suda.edu.cn [Department of Electrical and Computer Engineering, Dalhousie University, Halifax, Nova Scotia B3J 2X4 (Canada)

2016-08-08

We report experimental generation and measurement of recently introduced optical coherence lattices. The presented optical coherence lattice realization technique hinges on a superposition of mutually uncorrelated partially coherent Schell-model beams with tailored coherence properties. We show theoretically that information can be encoded into and, in principle, recovered from the lattice degree of coherence. Our results can find applications to image transmission and optical encryption.

Rhizobium leguminosarum bv. trifolii rosR is required for interaction with clover, biofilm formation and adaptation to the environment

Directory of Open Access Journals (Sweden)

Piersiak Tomasz

2010-11-01

Full Text Available Abstract Background Rhizobium leguminosarum bv. trifolii is a symbiotic nitrogen-fixing bacterium that elicits nodules on roots of host plants Trifolium spp. Bacterial surface polysaccharides are crucial for establishment of a successful symbiosis with legumes that form indeterminate-type nodules, such as Trifolium, Pisum, Vicia, and Medicago spp. and aid the bacterium in withstanding osmotic and other environmental stresses. Recently, the R. leguminosarum bv. trifolii RosR regulatory protein which controls exopolysaccharide production has been identified and characterized. Results In this work, we extend our earlier studies to the characterization of rosR mutants which exhibit pleiotropic phenotypes. The mutants produce three times less exopolysaccharide than the wild type, and the low-molecular-weight fraction in that polymer is greatly reduced. Mutation in rosR also results in quantitative alterations in the polysaccharide constituent of lipopolysaccharide. The rosR mutants are more sensitive to surface-active detergents, antibiotics of the beta-lactam group and some osmolytes, indicating changes in the bacterial membranes. In addition, the rosR mutants exhibit significant decrease in motility and form a biofilm on plastic surfaces, which differs significantly in depth, architecture, and bacterial viability from that of the wild type. The most striking effect of rosR mutation is the considerably decreased attachment and colonization of root hairs, indicating that the mutation affects the first stage of the invasion process. Infection threads initiate at a drastically reduced rate and frequently abort before they reach the base of root hairs. Although these mutants form nodules on clover, they are unable to fix nitrogen and are outcompeted by the wild type in mixed inoculations, demonstrating that functional rosR is important for competitive nodulation. Conclusions This report demonstrates the significant role RosR regulatory protein plays in

Does introduction of clover in an agricultural grassland affect the food base and functional diversity of Collembola?

DEFF Research Database (Denmark)

D'Annibale, Alessandra; Sechi, Valentina; Larsen, Thomas

2017-01-01

plots with either perennial ryegrass (Lolium perenne L.), whiteclover (Trifolium repens L.) or a mixture of both in a Danish agricultural grassland 6 and 14 months after establishing the leys (September and May, respectively). Diet preferences were investigated via stable isotope analyses (SIA...... in the white clover than ryegrass plots. Changes in taxa specific density and traits distribution as a response to the C:N ratio of plant material, suggest that plant material quality was the main factor affecting the collembolan community,especially when comparing the two sampling occasions. Functional...... richness decreased under conditions of low quality material. In contrast to our hypothesis, population densities did not increase under mixture treatment and functional richness decreased. Our results suggest that habitat changes, via different plant composition, can affect some functional groups, having...

APS-U LATTICE DESIGN FOR OFF-AXIS ACCUMULATION

Energy Technology Data Exchange (ETDEWEB)

Sun, Yipeng; Borland, M.; Lindberg, R.; Sajaev, V.

2017-06-25

A 67-pm hybrid-seven-bend achromat (H7BA) lattice is being proposed for a future Advanced Photon Source (APS) multi-bend-achromat (MBA) upgrade project. This lattice design pushes for smaller emittance and requires use of a swap-out (on-axis) injection scheme due to limited dynamic acceptance. Alternate lattice design work has also been performed for the APS upgrade to achieve better beam dynamics performance than the nominal APS MBA lattice, in order to allow off-axis accumulation. Two such alternate H7BA lattice designs, which target a still-low emittance of 90 pm, are discussed in detail in this paper. Although the single-particle-dynamics performance is good, simulations of collective effects indicate that surprising difficulty would be expected accumulating high single-bunch charge in this lattice. The brightness of the 90-pm lattice is also a factor of two lower than the 67-pm H7BA lattice.

Report of the workshop on realistic SSC lattices

International Nuclear Information System (INIS)

1985-10-01

A workshop was held at the SSC Central Design Group from May 29 to June 4, 1985, on topics relating to the lattice of the SSC. The workshop marked a shift of emphasis from the investigation of simplified test lattices to the development of a realistic lattice suitable for the conceptual design report. The first day of the workshop was taken up by reviews of accelerator system requirements, of the reference design solutions for these requirements, of lattice work following the reference design, and of plans for the workshop. The work was divided among four working groups. The first, chaired by David Douglas, concerned the arcs of regular cells. The second group, which studied the utility insertions, was chaired by Beat Leemann. The third group, under David E. Johnson, concerned itself with the experimental insertions, dispersion suppressors, and phase trombones. The fourth group, responsible for global lattice considerations and the design of a new realistic lattice example, was led by Ernest Courant. The papers resulting from this workshop are roughly divided into three sets: those relating to specific lattice components, to complete lattices, and to other topics. Among the salient accomplishments of the workshop were additions to and optimization of lattice components, especially those relating to lattices using 1-in-1 magnets, either horizontally or vertically separated, and the design of complete lattice examples. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database

Lattice location of diffused Zn atoms in GaAs and InP single crystals

International Nuclear Information System (INIS)

Chan, L.Y.; Yu, K.M.; Ben-Tzur, M.; Haller, E.E.; Jaklevic, J.M.; Walukiewicz, W.; Hanson, C.M.

1991-01-01

We have investigated the saturation phenomenon of the free carrier concentration in p-type GaAs and InP single crystals doped by zinc diffusion. The free hole saturation occurs at 10 20 cm -3 for GaAs, but the maximum concentration for InP appears at mid 10 18 cm -3 . The difference in the saturation hole concentrations for these materials is investigated by studying the incorporation and the lattice location of the impurity zinc, an acceptor when located on a group III atom site. Zinc is diffused into the III-V wafers in a sealed quartz ampoule. Particle-induced x-ray emission with ion-channeling techniques are employed to determine the exact lattice location of the zinc atoms. We have found that over 90% of all zinc atoms occupy Ga sites in the diffused GaAs samples, while for the InP case, the zinc substitutionality is dependent on the cooling rate of the sample after high-temperature diffusion. For the slowly cooled sample, a large fraction (∼90%) of the zinc atoms form random precipitates of Zn 3 P 2 and elemental Zn. However, when rapidly cooled only 60% of the zinc forms such precipitates while the rest occupies specific sites in the InP. We analyze our results in terms of the amphoteric native defect model. We show that the difference in the electrical activity of the Zn atoms in GaAs and InP is a consequence of the different location of the Fermi level stabilization energy in these two materials

Coupled matter-wave solitons in optical lattices

Science.gov (United States)

Golam Ali, Sk; Talukdar, B.

2009-06-01

We make use of a potential model to study the dynamics of two coupled matter-wave or Bose-Einstein condensate (BEC) solitons loaded in optical lattices. With separate attention to linear and nonlinear lattices we find some remarkable differences for response of the system to effects of these lattices. As opposed to the case of linear optical lattice (LOL), the nonlinear lattice (NOL) can be used to control the mutual interaction between the two solitons. For a given lattice wave number k, the effective potentials in which the two solitons move are such that the well (Veff(NOL)), resulting from the juxtaposition of soliton interaction and nonlinear lattice potential, is deeper than the corresponding well Veff(LOL). But these effective potentials have opposite k dependence in the sense that the depth of Veff(LOL) increases as k increases and that of Veff(NOL) decreases for higher k values. We verify that the effectiveness of optical lattices to regulate the motion of the coupled solitons depends sensitively on the initial locations of the motionless solitons as well as values of the lattice wave number. For both LOL and NOL the two solitons meet each other due to mutual interaction if their initial locations are taken within the potential wells with the difference that the solitons in the NOL approach each other rather rapidly and take roughly half the time to meet as compared with the time needed for such coalescence in the LOL. In the NOL, the soliton profiles can move freely and respond to the lattice periodicity when the separation between their initial locations are as twice as that needed for a similar free movement in the LOL. We observe that, in both cases, slow tuning of the optical lattices by varying k with respect to a time parameter τ drags the oscillatory solitons apart to take them to different locations. In our potential model the oscillatory solitons appear to propagate undistorted. But a fully numerical calculation indicates that during evolution

Coupled matter-wave solitons in optical lattices

International Nuclear Information System (INIS)

Golam Ali, Sk; Talukdar, B.

2009-01-01

We make use of a potential model to study the dynamics of two coupled matter-wave or Bose-Einstein condensate (BEC) solitons loaded in optical lattices. With separate attention to linear and nonlinear lattices we find some remarkable differences for response of the system to effects of these lattices. As opposed to the case of linear optical lattice (LOL), the nonlinear lattice (NOL) can be used to control the mutual interaction between the two solitons. For a given lattice wave number k, the effective potentials in which the two solitons move are such that the well (V eff (NOL)), resulting from the juxtaposition of soliton interaction and nonlinear lattice potential, is deeper than the corresponding well V eff (LOL). But these effective potentials have opposite k dependence in the sense that the depth of V eff (LOL) increases as k increases and that of V eff (NOL) decreases for higher k values. We verify that the effectiveness of optical lattices to regulate the motion of the coupled solitons depends sensitively on the initial locations of the motionless solitons as well as values of the lattice wave number. For both LOL and NOL the two solitons meet each other due to mutual interaction if their initial locations are taken within the potential wells with the difference that the solitons in the NOL approach each other rather rapidly and take roughly half the time to meet as compared with the time needed for such coalescence in the LOL. In the NOL, the soliton profiles can move freely and respond to the lattice periodicity when the separation between their initial locations are as twice as that needed for a similar free movement in the LOL. We observe that, in both cases, slow tuning of the optical lattices by varying k with respect to a time parameter τ drags the oscillatory solitons apart to take them to different locations. In our potential model the oscillatory solitons appear to propagate undistorted. But a fully numerical calculation indicates that during

Design of the SPEAR 3 magnet lattice

International Nuclear Information System (INIS)

Corbett, J.; Limborg, C.; Nosochkov, Y.; Safranek, J.

1998-01-01

The SPEAR 3 Upgrade Project seeks to replace the present 160 nm-rad FODO lattice with an 18 nm-rad double bend achromat (DBA) lattice. The new lattice must conform to the layout of the SPEAR racetrack tunnel and service the existing photon beamlines. Working within these constraints, the authors designed a lattice with 18 achromatic cells and 3 GeV beam energy. This paper reports on design of the main DBA cells, design of the matching cells leading into the 6.5 m racetrack straights, and simulation of the dynamic aperture. The new lattice has gradient dipoles, conventional quadrupoles, and provides horizontal dynamic aperture to ± 20 mm with conservative magnetic multipole errors

Efficient LBM visual simulation on face-centered cubic lattices.

Science.gov (United States)

Petkov, Kaloian; Qiu, Feng; Fan, Zhe; Kaufman, Arie E; Mueller, Klaus

2009-01-01

The Lattice Boltzmann method (LBM) for visual simulation of fluid flow generally employs cubic Cartesian (CC) lattices such as the D3Q13 and D3Q19 lattices for the particle transport. However, the CC lattices lead to suboptimal representation of the simulation space. We introduce the face-centered cubic (FCC) lattice, fD3Q13, for LBM simulations. Compared to the CC lattices, the fD3Q13 lattice creates a more isotropic sampling of the simulation domain and its single lattice speed (i.e., link length) simplifies the computations and data storage. Furthermore, the fD3Q13 lattice can be decomposed into two independent interleaved lattices, one of which can be discarded, which doubles the simulation speed. The resulting LBM simulation can be efficiently mapped to the GPU, further increasing the computational performance. We show the numerical advantages of the FCC lattice on channeled flow in 2D and the flow-past-a-sphere benchmark in 3D. In both cases, the comparison is against the corresponding CC lattices using the analytical solutions for the systems as well as velocity field visualizations. We also demonstrate the performance advantages of the fD3Q13 lattice for interactive simulation and rendering of hot smoke in an urban environment using thermal LBM.

Instantons and topological charge in lattice gauge theory

International Nuclear Information System (INIS)

Iwasaki, Y.; Yoshie, T.

1983-01-01

The existence of instantons on the lattice in SU(2) lattice gauge theory is investigated for various lattice actions with loops of up to six lattice spacings. Instantons exist only for the actions where short range fluctuations are suppressed. A formula for topological properties of the solutions are examined. (orig.)

Supersymmetry on a space-time lattice

International Nuclear Information System (INIS)

Kaestner, Tobias

2008-01-01

In this thesis the WZ model in one and two dimensions has been thoroughly investigated. With the help of the Nicolai map it was possible to construct supersymmetrically improved lattice actions that preserve one of several supersymmetries. For the WZ model in one dimension SLAC fermions were utilized for the first time leading to a near-perfect elimination of lattice artifacts. In addition the lattice superpotential does not get modified which in two dimensions becomes important when further (discrete) symmetries of the continuum action are considered. For Wilson fermions two new improvements have been suggested and were shown to yield far better results than standard Wilson fermions concerning lattice artifacts. In the one-dimensional theory Ward Identities were studied.However, supersymmetry violations due to broken supersymmetry could only be detected at coarse lattices and very strong couplings. For the two-dimensional models a detailed analysis of supersymmetric improvement terms was given, both for Wilson and SLAC fermions. (orig.)

Supersymmetry on a space-time lattice

Energy Technology Data Exchange (ETDEWEB)

Kaestner, Tobias

2008-10-28

In this thesis the WZ model in one and two dimensions has been thoroughly investigated. With the help of the Nicolai map it was possible to construct supersymmetrically improved lattice actions that preserve one of several supersymmetries. For the WZ model in one dimension SLAC fermions were utilized for the first time leading to a near-perfect elimination of lattice artifacts. In addition the lattice superpotential does not get modified which in two dimensions becomes important when further (discrete) symmetries of the continuum action are considered. For Wilson fermions two new improvements have been suggested and were shown to yield far better results than standard Wilson fermions concerning lattice artifacts. In the one-dimensional theory Ward Identities were studied.However, supersymmetry violations due to broken supersymmetry could only be detected at coarse lattices and very strong couplings. For the two-dimensional models a detailed analysis of supersymmetric improvement terms was given, both for Wilson and SLAC fermions. (orig.)

Synthesizing lattice structures in phase space

International Nuclear Information System (INIS)

Guo, Lingzhen; Marthaler, Michael

2016-01-01

In one dimensional systems, it is possible to create periodic structures in phase space through driving, which is called phase space crystals (Guo et al 2013 Phys. Rev. Lett. 111 205303). This is possible even if for particles trapped in a potential without periodicity. In this paper we discuss ultracold atoms in a driven optical lattice, which is a realization of such a phase space crystals. The corresponding lattice structure in phase space is complex and contains rich physics. A phase space lattice differs fundamentally from a lattice in real space, because its coordinate system, i.e., phase space, has a noncommutative geometry, which naturally provides an artificial gauge (magnetic) field. We study the behavior of the quasienergy band structure and investigate the dissipative dynamics. Synthesizing lattice structures in phase space provides a new platform to simulate the condensed matter phenomena and study the intriguing phenomena of driven systems far away from equilibrium. (paper)

Graphene antidot lattice waveguides

DEFF Research Database (Denmark)

Pedersen, Jesper Goor; Gunst, Tue; Markussen, Troels

2012-01-01

We introduce graphene antidot lattice waveguides: nanostructured graphene where a region of pristine graphene is sandwiched between regions of graphene antidot lattices. The band gaps in the surrounding antidot lattices enable localized states to emerge in the central waveguide region. We model...... the waveguides via a position-dependent mass term in the Dirac approximation of graphene and arrive at analytical results for the dispersion relation and spinor eigenstates of the localized waveguide modes. To include atomistic details we also use a tight-binding model, which is in excellent agreement...... with the analytical results. The waveguides resemble graphene nanoribbons, but without the particular properties of ribbons that emerge due to the details of the edge. We show that electrons can be guided through kinks without additional resistance and that transport through the waveguides is robust against...

Multispeed models in off-lattice Boltzmann simulations

NARCIS (Netherlands)

Bardow, A.; Karlin, I.V.; Gusev, A.A.

2008-01-01

The lattice Boltzmann method is a highly promising approach to the simulation of complex flows. Here, we realize recently proposed multispeed lattice Boltzmann models [S. Chikatamarla et al., Phys. Rev. Lett. 97 190601 (2006)] by exploiting the flexibility offered by off-lattice Boltzmann methods.

Lattice QCD: Status and Prospect

International Nuclear Information System (INIS)

Ukawa, Akira

2006-01-01

A brief review is given of the current status and near-future prospect of lattice QCD studies of the Standard Model. After summarizing a bit of history, we describe current attempts toward inclusion of dynamical up, down and strange quarks. Recent results on the light hadron mass spectrum as well as those on the heavy quark quantities are described. Recent work on lattice pentaquark search is summarized. We touch upon the PACS-CS Project for building our next machine for lattice QCD, and conclude with a summary of computer situation and the physics possibilities over the next several years

The growth of minicircle networks on regular lattices

International Nuclear Information System (INIS)

Diao, Y; Hinson, K; Arsuaga, J

2012-01-01

The mitochondrial DNA of trypanosomes is organized into a network of topologically linked minicircles. In order to investigate how key topological properties of the network change with minicircle density, the authors introduced, in an earlier study, a mathematical model in which randomly oriented minicircles were placed on the vertices of the simple square lattice. Using this model, the authors rigorously showed that when the density of minicircles increases, percolation clusters form. For higher densities, these percolation clusters are the backbones for networks of minicircles that saturate the entire lattice. An important relevant question is whether these findings are generally true. That is, whether these results are independent of the choice of the lattices on which the model is based. In this paper, we study two additional lattices (namely the honeycomb and the triangular lattices). These regular lattices are selected because they have been proposed for trypanosomes before and after replication. We compare our findings with our earlier results on the square lattice and show that the mathematical statements derived for the square lattice can be extended to these other lattices qualitatively. This finding suggests the universality of these properties. Furthermore, we performed a numerical study which provided data that are consistent with our theoretical analysis, and showed that the effect of the choice of lattices on the key network topological characteristics is rather small. (paper)

An integrable coupling family of Merola-Ragnisco-Tu lattice systems, its Hamiltonian structure and related nonisospectral integrable lattice family

Energy Technology Data Exchange (ETDEWEB)

Xu Xixiang, E-mail: xu_xixiang@hotmail.co [College of Science, Shandong University of Science and Technology, Qingdao, 266510 (China)

2010-01-04

An integrable coupling family of Merola-Ragnisco-Tu lattice systems is derived from a four-by-four matrix spectral problem. The Hamiltonian structure of the resulting integrable coupling family is established by the discrete variational identity. Each lattice system in the resulting integrable coupling family is proved to be integrable discrete Hamiltonian system in Liouville sense. Ultimately, a nonisospectral integrable lattice family associated with the resulting integrable lattice family is constructed through discrete zero curvature representation.

An integrable coupling family of Merola-Ragnisco-Tu lattice systems, its Hamiltonian structure and related nonisospectral integrable lattice family

International Nuclear Information System (INIS)

Xu Xixiang

2010-01-01

An integrable coupling family of Merola-Ragnisco-Tu lattice systems is derived from a four-by-four matrix spectral problem. The Hamiltonian structure of the resulting integrable coupling family is established by the discrete variational identity. Each lattice system in the resulting integrable coupling family is proved to be integrable discrete Hamiltonian system in Liouville sense. Ultimately, a nonisospectral integrable lattice family associated with the resulting integrable lattice family is constructed through discrete zero curvature representation.

Arbitrary spin fermions on the lattice

International Nuclear Information System (INIS)

Bullinaria, J.A.

1985-01-01

Lattice actions are constructed for free Dirac and Majorana fermions of arbitrary (half-integer) spin various extensions of the spin 1/2 Kogut-Susskind, Kaehler and Wilson formalisms. In each case, the spectrum degeneracy and preservation of gauge invariance is analysed, and the equivalence or non-equivalence to previously constructed actions is determined. The Kogut-Susskind and lattice Kaehler actions are then written explicitly in terms of spinors to demonstrate how the degenerate fermions couple on the lattice and how the original spinorial actions are recovered (or to recovered) in the continuum limit. Both degenerate and non-degenerate mass terms are dealt with and the various U(1) invariances of the lattice actions are pointed out

An Active Lattice Model in a Bayesian Framework

DEFF Research Database (Denmark)

Carstensen, Jens Michael

1996-01-01

A Markov Random Field is used as a structural model of a deformable rectangular lattice. When used as a template prior in a Bayesian framework this model is powerful for making inferences about lattice structures in images. The model assigns maximum probability to the perfect regular lattice...... by penalizing deviations in alignment and lattice node distance. The Markov random field represents prior knowledge about the lattice structure, and through an observation model that incorporates the visual appearance of the nodes, we can simulate realizations from the posterior distribution. A maximum...... a posteriori (MAP) estimate, found by simulated annealing, is used as the reconstructed lattice. The model was developed as a central part of an algorithm for automatic analylsis of genetic experiments, positioned in a lattice structure by a robot. The algorithm has been successfully applied to many images...

Thermodynamics of lattice QCD with 2 sextet quarks on Nt=8 lattices

International Nuclear Information System (INIS)

Kogut, J. B.; Sinclair, D. K.

2011-01-01

We continue our lattice simulations of QCD with 2 flavors of color-sextet quarks as a model for conformal or walking technicolor. A 2-loop perturbative calculation of the β function which describes the evolution of this theory's running coupling constant predicts that it has a second zero at a finite coupling. This nontrivial zero would be an infrared stable fixed point, in which case the theory with massless quarks would be a conformal field theory. However, if the interaction between quarks and antiquarks becomes strong enough that a chiral condensate forms before this IR fixed point is reached, the theory is QCD-like with spontaneously broken chiral symmetry and confinement. However, the presence of the nearby IR fixed point means that there is a range of couplings for which the running coupling evolves very slowly, i.e. it ''walks.'' We are simulating the lattice version of this theory with staggered quarks at finite temperature, studying the changes in couplings at the deconfinement and chiral-symmetry restoring transitions as the temporal extent (N t ) of the lattice, measured in lattice units, is increased. Our earlier results on lattices with N t =4, 6 show both transitions move to weaker couplings as N t increases consistent with walking behavior. In this paper we extend these calculations to N t =8. Although both transitions again move to weaker couplings, the change in the coupling at the chiral transition from N t =6 to N t =8 is appreciably smaller than that from N t =4 to N t =6. This indicates that at N t =4, 6 we are seeing strong-coupling effects and that we will need results from N t >8 to determine if the chiral-transition coupling approaches zero as N t →∞, as needed for the theory to walk.

Lattice calculation of nonleptonic charm decays

International Nuclear Information System (INIS)

Simone, J.N.

1991-11-01

The decays of charmed mesons into two body nonleptonic final states are investigated. Weak interaction amplitudes of interest in these decays are extracted from lattice four-point correlation functions using a effective weak Hamiltonian including effects to order G f in the weak interactions yet containing effects to all orders in the strong interactions. The lattice calculation allows a quantitative examination of non-spectator processes in charm decays helping to elucidate the role of effects such as color coherence, final state interactions and the importance of the so called weak annihilation process. For D → Kπ, we find that the non-spectator weak annihilation diagram is not small, and we interpret this as evidence for large final state interactions. Moreover, there is indications of a resonance in the isospin 1/2 channel to which the weak annihilation process contributes exclusively. Findings from the lattice calculation are compared to results from the continuum vacuum saturation approximation and amplitudes are examined within the framework of the 1/N expansion. Factorization and the vacuum saturation approximation are tested for lattice amplitudes by comparing amplitudes extracted from lattice four-point functions with the same amplitude extracted from products of two-point and three-point lattice correlation functions arising out of factorization and vacuum saturation

Disconnected Diagrams in Lattice QCD

Science.gov (United States)

Gambhir, Arjun Singh

In this work, we present state-of-the-art numerical methods and their applications for computing a particular class of observables using lattice quantum chromodynamics (Lattice QCD), a discretized version of the fundamental theory of quarks and gluons. These observables require calculating so called "disconnected diagrams" and are important for understanding many aspects of hadron structure, such as the strange content of the proton. We begin by introducing the reader to the key concepts of Lattice QCD and rigorously define the meaning of disconnected diagrams through an example of the Wick contractions of the nucleon. Subsequently, the calculation of observables requiring disconnected diagrams is posed as the computationally challenging problem of finding the trace of the inverse of an incredibly large, sparse matrix. This is followed by a brief primer of numerical sparse matrix techniques that overviews broadly used methods in Lattice QCD and builds the background for the novel algorithm presented in this work. We then introduce singular value deflation as a method to improve convergence of trace estimation and analyze its effects on matrices from a variety of fields, including chemical transport modeling, magnetohydrodynamics, and QCD. Finally, we apply this method to compute observables such as the strange axial charge of the proton and strange sigma terms in light nuclei. The work in this thesis is innovative for four reasons. First, we analyze the effects of deflation with a model that makes qualitative predictions about its effectiveness, taking only the singular value spectrum as input, and compare deflated variance with different types of trace estimator noise. Second, the synergy between probing methods and deflation is investigated both experimentally and theoretically. Third, we use the synergistic combination of deflation and a graph coloring algorithm known as hierarchical probing to conduct a lattice calculation of light disconnected matrix elements

Disconnected Diagrams in Lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Gambhir, Arjun [College of William and Mary, Williamsburg, VA (United States)

2017-08-01

In this work, we present state-of-the-art numerical methods and their applications for computing a particular class of observables using lattice quantum chromodynamics (Lattice QCD), a discretized version of the fundamental theory of quarks and gluons. These observables require calculating so called \\disconnected diagrams" and are important for understanding many aspects of hadron structure, such as the strange content of the proton. We begin by introducing the reader to the key concepts of Lattice QCD and rigorously define the meaning of disconnected diagrams through an example of the Wick contractions of the nucleon. Subsequently, the calculation of observables requiring disconnected diagrams is posed as the computationally challenging problem of finding the trace of the inverse of an incredibly large, sparse matrix. This is followed by a brief primer of numerical sparse matrix techniques that overviews broadly used methods in Lattice QCD and builds the background for the novel algorithm presented in this work. We then introduce singular value deflation as a method to improve convergence of trace estimation and analyze its effects on matrices from a variety of fields, including chemical transport modeling, magnetohydrodynamics, and QCD. Finally, we apply this method to compute observables such as the strange axial charge of the proton and strange sigma terms in light nuclei. The work in this thesis is innovative for four reasons. First, we analyze the effects of deflation with a model that makes qualitative predictions about its effectiveness, taking only the singular value spectrum as input, and compare deflated variance with different types of trace estimator noise. Second, the synergy between probing methods and deflation is investigated both experimentally and theoretically. Third, we use the synergistic combination of deflation and a graph coloring algorithm known as hierarchical probing to conduct a lattice calculation of light disconnected matrix elements

A study of the red clover extract trinovin by ESR HPLC/MS and UVS

International Nuclear Information System (INIS)

Troup, G.; Hutton, D.; Hunter, C.; Hewitt, D.; Mulinacci, N.; Romani, A.; Pinelli, P.; Mancini, P.

1999-01-01

Full text: Trinovin is an extract of red clover, recently released on the dietary supplement market. It is recommended for 'Men's Health', because it contains the phenolics (isoflavones) genistein, biochanin, daidzein and formononetin, said to act as 'phytoestrogens', and is therefore a possible help in prostate gland problems. An Electron Spin Resonance (ESR) study (∼9.1Ghz, room temperature) revealed at least 3 different free radical lines, one with hyperfine structure, consistent with the listed molecules. Accordingly, HPLC/DAD (High Performance Liquid Chromatography/Diode Array Detector) and HPLC/Mass Spectroscopy analyses were performed in order to evaluate the quali-quantitative contents of flavonoidic compounds. The HPLC profile shows two main isoflavones and another three compounds, one of them being a quercetin glycoside. The quercetin glycosides are flavonoidic derivatives abundant in plant materials and present in wine. We can therefore say: even if the phytoestrogen properties claimed for Trinovin turn out to be less than hoped for, the antioxidants contained are very powerful, and so possibly helpful in protection against many diseases, including cancers, atherosclerosis, diabetic retinal bleeding, and non-alcoholic dementia

Remarks on lattice gauge models

International Nuclear Information System (INIS)

Grosse, H.

1981-01-01

The author reports a study of the phase structure of lattice gauge models where one takes as a gauge group a non-abelian discrete subgroup of SU(3). In addition he comments on a lattice action proposed recently by Manton and observes that it violates a positivity property. (Auth.)

Technological development for super-high efficiency solar cells. Technological development for crystalline compound solar cells (high-efficiency III-V tandem solar cells); Chokokoritsu taiyo denchi no gijutsu kaihatsu. Kessho kagobutsu taiyo denchi no gijutsu kaihatsu (III-V zoku kagobutsu handotai taiyo denchi no gijutsu kaihatsu)

Energy Technology Data Exchange (ETDEWEB)

Tatsuta, M [New Energy and Industrial Technology Development Organization, Tokyo (Japan)

1994-12-01

This paper reports the study results on technological development of III-V compound semiconductor solar cells in fiscal 1994. (1) On development of epitaxial growth technology of lattice mismatching systems, the optimum structure of InGaAs strain intermediate layers was studied for reducing a dislocation density by lattice mismatching of GaAs layer grown on Si substrate and difference in thermal expansion coefficient. The effect of strain layer on dislocation reduction was found only at 250dyne/cm in strain energy. Growth of GaAs layers on the Si substrate treated by hydrofluoric acid at low temperature was attempted by MBE method. As a dislocation distribution was controlled by laying different atoms at hetero-interface, the dislocation density of growing layer surfaces decreased by concentration of dislocation at hetero-interface. (2) On development of high-efficiency tandem cell structure, tunnel junction characteristics, cell formation process and optimum design method of lattice matching tandem cells were studied, while thin film cell formation was basically studied for lattice mismatching tandem cells. 45 figs., 8 tabs.

Clar sextets in square graphene antidot lattices

DEFF Research Database (Denmark)

Petersen, Rene; Pedersen, Thomas Garm; Jauho, Antti-Pekka

2011-01-01

A periodic array of holes transforms graphene from a semimetal into a semiconductor with a band gap tuneable by varying the parameters of the lattice. In earlier work only hexagonal lattices have been treated. Using atomistic models we here investigate the size of the band gap of a square lattice...

Electric Dipole Moment Results from lattice QCD

Directory of Open Access Journals (Sweden)

Dragos Jack

2018-01-01

Full Text Available We utilize the gradient flow to define and calculate electric dipole moments induced by the strong QCD θ-term and the dimension-6 Weinberg operator. The gradient flow is a promising tool to simplify the renormalization pattern of local operators. The results of the nucleon electric dipole moments are calculated on PACS-CS gauge fields (available from the ILDG using Nf = 2+1, of discrete size 323×64 and spacing a ≃ 0.09 fm. These gauge fields use a renormalization-group improved gauge action and a nonperturbatively O(a improved clover quark action at β = 1.90, with cSW = 1.715. The calculation is performed at pion masses of mπ ≃ 411, 701 MeV.

Meat goat kids finished on alfalfa, red clover or orchardgrass pastures: carcass merit and meat quality.

Science.gov (United States)

Turner, K E; Cassida, K A; Zerby, H N

2014-12-01

This experiment was conducted in 2005-2007 to evaluate carcass and chevon (goat meat) quality parameters when meat-goat kids (n=72) were finished on alfalfa (Medicago sativa L; ALF); red clover (Trifolium pratense L.; RCG); or orchardgrass (Dactylis glomerata L.; OGR) pastures. Carcass conformation score was greater (P=0.08) when meat-goat kids were finished on ALF compared to OGR with RCG intermediate. Chevon meat samples from goats finished on the three pasture treatments did not differ in ash, intramuscular fat, or crude protein content or in concentrations of omega6 and omega3 fatty acids, or the omega6 to omega3 ratio. Goats finished on OGR had higher (Pmeat-goat kids finished on ALF, RCG, or ORG produced desirable carcass weights for most niche markets in the USA. Chevon is a low-fat meat option with high desirable fatty acids for human diets. Published by Elsevier Ltd.

Polish Yellow Sweet Clover (Melilotus officinalis L. Honey, Chromatographic Fingerprints, and Chemical Markers

Directory of Open Access Journals (Sweden)

Izabela Jasicka-Misiak

2017-01-01

Full Text Available A case study of Polish Melilotus officinalis honey was presented for the first time. Gas chromatography–mass spectrometry (GC-MS (after steam distillation, Soxhlet extraction, ultrasonic solvent extraction, and solid phase extraction (SPE and targeted high performance liquid chromatography with a photodiode array detector (HPLC-PAD were applied to determine the characteristic components of honey. While ubiquitous in most honeys, carbohydrates, terpene derivatives, and phenylacetic acid dominated in the Soxhlet extracts (25.54% and in the application of SPE (13.04%. In addition, lumichrome (1.85% was found, and may be considered as a marker of this honey. Due to the presence of these compounds, Polish yellow sweet clover honey is similar to French lavender honeys. The major compounds determined in the methanolic extract were (+-catechine (39.7% and gallic acid (up to 30%, which can be regarded as specific chemical markers of the botanical origin of melilot honey. With respect to total phenolic and flavonoid contents, 1,1-diphenyl-2-picrylhydrazyl (DPPH assays were determined spectrophotometrically. The honey exhibited a moderate antioxidant activity, typical for light honeys, which correlates well with its phenolic and flavonoid composition.

Toda lattice field theories, discrete W algebras, Toda lattice hierarchies and quantum groups

International Nuclear Information System (INIS)

Bonora, L.; Colatto, L.P.; Constantinidis, C.P.

1996-05-01

In analogy with the Liouville case, we study the sl 3 Toda theory on the lattice and define the relevant quadratic algebra and out of it we recover the discrete W 3 algebra. We define an integrable system with respect to the latter and establish the relation with the Toda lattice hierarchy. We compute the relevant continuum limits. Finally we find the quantum version of the quadratic algebra. (author). 16 refs

High spatial variation in population size and symbiotic performance of Rhizobium leguminosarum bv. trifolii with white clover in New Zealand pasture soils

Science.gov (United States)

Tillard, Guyléne; van Ham, Robert; Ballard, Ross; Farquharson, Elizabeth; Gerard, Emily; Geurts, Rene; Brown, Matthew; Ridgway, Hayley; O’Callaghan, Maureen

2018-01-01

Biological nitrogen fixation through the legume-rhizobia symbiosis is important for sustainable pastoral production. In New Zealand, the most widespread and valuable symbiosis occurs between white clover (Trifolium repens L.) and Rhizobium leguminosarum bv. trifolii (Rlt). As variation in the population size (determined by most probable number assays; MPN) and effectiveness of N-fixation (symbiotic potential; SP) of Rlt in soils may affect white clover performance, the extent in variation in these properties was examined at three different spatial scales: (1) From 26 sites across New Zealand, (2) at farm-wide scale, and (3) within single fields. Overall, Rlt populations ranged from 95 to >1 x 108 per g soil, with variation similar at the three spatial scales assessed. For almost all samples, there was no relationship between rhizobia population size and ability of the population to fix N during legume symbiosis (SP). When compared with the commercial inoculant strain, the SP of soils ranged between 14 to 143% efficacy. The N-fixing ability of rhizobia populations varied more between samples collected from within a single hill country field (0.8 ha) than between 26 samples collected from diverse locations across New Zealand. Correlations between SP and calcium and aluminium content were found in all sites, except within a dairy farm field. Given the general lack of association between SP and MPN, and high spatial variability of SP at single field scale, provision of advice for treating legume seed with rhizobia based on field-average MPN counts needs to be carefully considered. PMID:29489845

Polarization response of RHIC electron lens lattices

Directory of Open Access Journals (Sweden)

V. H. Ranjbar

2016-10-01

Full Text Available Depolarization response for a system of two orthogonal snakes at irrational tunes is studied in depth using lattice independent spin integration. In particular we consider the effect of overlapping spin resonances in this system, to understand the impact of phase, tune, relative location and threshold strengths of the spin resonances. These results are benchmarked and compared to two dimensional direct tracking results for the RHIC e-lens lattice and the standard lattice. Finally we consider the effect of longitudinal motion via chromatic scans using direct six dimensional lattice tracking.

Advancements in simulations of lattice quantum chromodynamics

International Nuclear Information System (INIS)

Lippert, T.

2008-01-01

An introduction to lattice QCD with emphasis on advanced fermion formulations and their simulation is given. In particular, overlap fermions will be presented, a quite novel fermionic discretization scheme that is able to exactly preserve chiral symmetry on the lattice. I will discuss efficiencies of state-of-the-art algorithms on highly scalable supercomputers and I will show that, due to many algorithmic improvements, overlap simulations will soon become feasible for realistic physical lattice sizes. Finally I am going to sketch the status of some current large scale lattice QCD simulations. (author)

Polarization response of RHIC electron lens lattices

International Nuclear Information System (INIS)

Ranjbar, V. H.; Méot, F.; Bai, M.; Abell, D. T.; Meiser, D.

2016-01-01

Depolarization response for a system of two orthogonal snakes at irrational tunes is studied in depth using lattice independent spin integration. Particularly, we consider the effect of overlapping spin resonances in this system, to understand the impact of phase, tune, relative location and threshold strengths of the spin resonances. Furthermore, these results are benchmarked and compared to two dimensional direct tracking results for the RHIC e-lens lattice and the standard lattice. We then consider the effect of longitudinal motion via chromatic scans using direct six dimensional lattice tracking.

Lattice defects in LPE InP-InGaAsP-InGaAs structure epitaxial layers on InP substrates

International Nuclear Information System (INIS)

Ishida, K.; Matsumoto, Y.; Taguchi, K.

1982-01-01

Lattice defects generated during LPE growth of InP-InGaAsP-InGaAs structure epitaxial layers on InP substrates are studied. Two different kinds of dislocations are observed at the two interfaces of the epitaxial layers; at the InP-InGaAsP interface, misfit dislocations are generated in the InP layer by carry over of InGaAsP melt into the InP one and at the InGaAs-InP interface, V-shaped dislocations are generated in the InGaAs layer. It is shown that the critical amount of lattice mismatch to suppress generation of misfit dislocations in InP is about two times smaller than that of other III-V compound semiconductors. Conditions to suppress the generation of these dislocations are clarified. (author)

Remarks on lattice gauge models

International Nuclear Information System (INIS)

Grosse, H.

1981-01-01

The author reports on a study of the phase structure of lattice gauge models where one takes as a gauge group a non-abelian discrete subgroup of SU(3). In addition he comments on a lattice action proposed recently by Manton (1980) and observes that it violates a positivity property. (Auth.)

Lattice Automata for Control of Self-Reconfigurable Robots

DEFF Research Database (Denmark)

Støy, Kasper

2015-01-01

are extreme versatility and robustness. The organisation of self-reconfigurable robots in a lattice structure and the emphasis on local communication between modules mean that lattice automata are a useful basis for control of self-reconfigurable robots. However, there are significant differences which arise...... mainly from the physical nature of self-reconfigurable robots as opposed to the virtual nature of lattice automata. The problems resulting from these differences are mutual exclusion, handling motion constraints of modules, and unrealistic assumption about global, spatial orientation. Despite...... these problems the self-reconfigurable robot community has successfully applied lattice automata to simple control problems. However, for more complex problems hybrid solutions based on lattice automata and distributed algorithms are used. Hence, lattice automata have shown to have potential for the control...

Locally Sensitive Lattice-Valued Possibilistic Entropy Functions

Czech Academy of Sciences Publication Activity Database

Kramosil, Ivan

2008-01-01

Roč. 18, č. 6 (2008), s. 469-488 ISSN 1210-0552 R&D Projects: GA AV ČR IAA100300503 Institutional research plan: CEZ:AV0Z10300504 Keywords : complete lattice * chained lattice * lattice-valued possibilistic distribution * possibilistic expected value Subject RIV: BA - General Mathematics Impact factor: 0.395, year: 2008

Bromido(1,4,7,10,13-pentaazacyclohexadecanecobalt(III dibromide dihydrate

Directory of Open Access Journals (Sweden)

Tsutomu Kurisaki

2013-04-01

Full Text Available The title salt, [CoBr(C11H27N5]Br2·2H2O, contains a complex cation with mirror symmetry and two Br− counter-anions that are likewise located on the mirror plane. The central CoIII atom of the complex cation has one Br− ion in an axial position, one N atom of the pentadentate macrocyclic ligand in the other axial position and four N atoms of the ligand in equatorial positions, defining a distorted octahedral coordination geometry. The macrocyclic ligand is coordinated to the CoIII atom within a 5, 6, 5 arrangement of chelate rings in the equatorial plane of the four N atoms. Due to symmetry, the configuration of the chiral N atoms is 1RS, 4SR, 10RS, 13SR. In the crystal, N—H...Br, O—H...Br and N—H...O hydrogen bonds between the complex cation, anions and lattice water molecules generate a three-dimensional network.

Interstructure Lattices and Types of Peano Arithmetic

Science.gov (United States)

Abdul-Quader, Athar

The collection of elementary substructures of a model of PA forms a lattice, and is referred to as the substructure lattice of the model. In this thesis, we study substructure and interstructure lattices of models of PA. We apply techniques used in studying these lattices to other problems in the model theory of PA. In Chapter 2, we study a problem that had its origin in Simpson ([Sim74]), who used arithmetic forcing to show that every countable model of PA has an expansion to PA* that is pointwise definable. Enayat ([Ena88]) later showed that there are 2N0 models with the property that every expansion to PA* is pointwise definable. In this Chapter, we use techniques involved in representations of lattices to show that there is a model of PA with this property which contains an infinite descending chain of elementary cuts. In Chapter 3, we study the question of when subsets can be coded in elementary end extensions with prescribed interstructure lattices. This problem originated in Gaifman [Gai76], who showed that every model of PA has a conservative, minimal elementary end extension. That is, every model of PA has a minimal elementary end extension which codes only definable sets. Kossak and Paris [KP92] showed that if a model is countable and a subset X can be coded in any elementary end extension, then it can be coded in a minimal extension. Schmerl ([Sch14] and [Sch15]) extended this work by considering which collections of sets can be the sets coded in a minimal elementary end extension. In this Chapter, we extend this work to other lattices. We study two questions: given a countable model M, which sets can be coded in an elementary end extension such that the interstructure lattice is some prescribed finite distributive lattice; and, given an arbitrary model M, which sets can be coded in an elementary end extension whose interstructure lattice is a finite Boolean algebra?

New methods for indexing multi-lattice diffraction data

International Nuclear Information System (INIS)

Gildea, Richard J.; Waterman, David G.; Parkhurst, James M.; Axford, Danny; Sutton, Geoff; Stuart, David I.; Sauter, Nicholas K.; Evans, Gwyndaf; Winter, Graeme

2014-01-01

A new indexing method is presented which is capable of indexing multiple crystal lattices from narrow wedges of data. The efficacy of this method is demonstrated with both semi-synthetic multi-lattice data and real multi-lattice data recorded from microcrystals of ∼1 µm in size. A new indexing method is presented which is capable of indexing multiple crystal lattices from narrow wedges of diffraction data. The method takes advantage of a simplification of Fourier transform-based methods that is applicable when the unit-cell dimensions are known a priori. The efficacy of this method is demonstrated with both semi-synthetic multi-lattice data and real multi-lattice data recorded from crystals of ∼1 µm in size, where it is shown that up to six lattices can be successfully indexed and subsequently integrated from a 1° wedge of data. Analysis is presented which shows that improvements in data-quality indicators can be obtained through accurate identification and rejection of overlapping reflections prior to scaling

Light Hadron Spectroscopy on course lattices with

CERN Document Server

Lee, F

1999-01-01

The masses and dispersions of light hadrons are calculated in lattice QCD using an O(a sup 2) tadpole-improved gluon action and an O(a sup 2) tadpole-improved next-nearest-neighbor fermion action originally proposed by Hamber and Wu. Two lattices of constant volume with lattice spacings of approximately 0.40 fm and 0.24 fm are considered. The results reveal some scaling violations at the coarser lattice spacing on the order of 5%. At the finer lattice spacing, the nucleon to rho mass ratio reproduces state-of-the-art results using unimproved actions. Good dispersion and rotational invariance up to momenta of pa approx = 1 are also found. The relative merit of alternative choices for improvement operators is assessed through close comparisons with other plaquette-based tadpole-improved actions.

Lattice-Valued Possibilistic Entropy Measure

Czech Academy of Sciences Publication Activity Database

Kramosil, Ivan

2008-01-01

Roč. 16, č. 6 (2008), s. 829-846 ISSN 0218-4885 R&D Projects: GA AV ČR IAA100300503 Institutional research plan: CEZ:AV0Z10300504 Keywords : complete lattice * lattice-valued possibilistic distribution * entropy measure * product of possibilistic distribution Subject RIV: BA - General Mathematics Impact factor: 1.000, year: 2008

Changes During Growth in Cell Wall Components of Berseem Clover Under Different Cutting Treatments in a Mediterranean Region

Directory of Open Access Journals (Sweden)

Giuditta De Santis

2007-09-01

Full Text Available Forage digestibility of berseem clover (Trifolium Alexandrinum L. is influenced by plant cell wall composition. This study was conducted to evaluate the effects of different cutting treatments on cell-wall components of the herbage and plant fractions in two Mediterranean berseem genotypes during growth and to examine the relationship between digestibility and cell wall components in these plant fractions. Cutting treatments were initiated at sixth internode elongation (A and early flowering (B and there was an uncut control treatment (C. Spring growth of genotypes of Egyptian (cv. Giza 10 and Italian (cv. Sacromonte origins was harvested in each of two years beginning 196 days after sowing and thereafter every 6 days (twelve harvests in total to measure cell wall components. Neutral detergent fibre (NDF, acid detergent fibre (ADF and acid detergent lignin (ADL concentrations were determined for leaf, stem, and total forage of each cultivar at each harvest. Without defoliation, NDF, ADF and ADL concentrations of herbage increased linearly to a maximum of 528, 375 and 84 g kg-1 DM, respectively, by 220 days after planting, when plant height reached maximum values, then plateaued until 257 days after planting. Plant parts differed in cell-wall concentration, with stems being of higher fibre components than leaves, in the two cutting treatments. Herbage and plant fraction fibre concentrations were negatively correlated with digestibility for all cutting treatments. Defoliation induced a reduction in fibre concentrations and plant height, although a rapid regrowth was observed after cutting, in both treatments A and B. However, delaying defoliation to the early flowering stage (B increased fibre components concentrations both at cutting time and during the growing season and significantly reduced the regrowth height. Conversely, plants cut at the sixth internode elongation (treatment A showed lower concentrations of fibre fractions than initiating

SSC lattice database and graphical interface

International Nuclear Information System (INIS)

Trahern, C.G.; Zhou, J.

1991-11-01

When completed the Superconducting Super Collider will be the world's largest accelerator complex. In order to build this system on schedule, the use of database technologies will be essential. In this paper we discuss one of the database efforts underway at the SSC, the lattice database. The SSC lattice database provides a centralized source for the design of each major component of the accelerator complex. This includes the two collider rings, the High Energy Booster, Medium Energy Booster, Low Energy Booster, and the LINAC as well as transfer and test beam lines. These designs have been created using a menagerie of programs such as SYNCH, DIMAD, MAD, TRANSPORT, MAGIC, TRACE3D AND TEAPOT. However, once a design has been completed, it is entered into a uniform database schema in the database system. In this paper we discuss the reasons for creating the lattice database and its implementation via the commercial database system SYBASE. Each lattice in the lattice database is composed of a set of tables whose data structure can describe any of the SSC accelerator lattices. In order to allow the user community access to the databases, a programmatic interface known as dbsf (for database to several formats) has been written. Dbsf creates ascii input files appropriate to the above mentioned accelerator design programs. In addition it has a binary dataset output using the Self Describing Standard data discipline provided with the Integrated Scientific Tool Kit software tools. Finally we discuss the graphical interfaces to the lattice database. The primary interface, known as OZ, is a simulation environment as well as a database browser

Three-wave electron vortex lattices for measuring nanofields.

Science.gov (United States)

Dwyer, C; Boothroyd, C B; Chang, S L Y; Dunin-Borkowski, R E

2015-01-01

It is demonstrated how an electron-optical arrangement consisting of two electron biprisms can be used to generate three-wave vortex lattices with effective lattice spacings between 0.1 and 1 nm. The presence of vortices in these lattices was verified by using a third biprism to perform direct phase measurements via off-axis electron holography. The use of three-wave lattices for nanoscale electromagnetic field measurements via vortex interferometry is discussed, including the accuracy of vortex position measurements and the interpretation of three-wave vortex lattices in the presence of partial spatial coherence. Copyright © 2014 Elsevier B.V. All rights reserved.

Fractional Quantum Field Theory: From Lattice to Continuum

Directory of Open Access Journals (Sweden)

Vasily E. Tarasov

2014-01-01

Full Text Available An approach to formulate fractional field theories on unbounded lattice space-time is suggested. A fractional-order analog of the lattice quantum field theories is considered. Lattice analogs of the fractional-order 4-dimensional differential operators are proposed. We prove that continuum limit of the suggested lattice field theory gives a fractional field theory for the continuum 4-dimensional space-time. The fractional field equations, which are derived from equations for lattice space-time with long-range properties of power-law type, contain the Riesz type derivatives on noninteger orders with respect to space-time coordinates.

Nucleon structure from lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Dinter, Simon

2012-11-13

In this thesis we compute within lattice QCD observables related to the structure of the nucleon. One part of this thesis is concerned with moments of parton distribution functions (PDFs). Those moments are essential elements for the understanding of nucleon structure and can be extracted from a global analysis of deep inelastic scattering experiments. On the theoretical side they can be computed non-perturbatively by means of lattice QCD. However, since the time lattice calculations of moments of PDFs are available, there is a tension between these lattice calculations and the results from a global analysis of experimental data. We examine whether systematic effects are responsible for this tension, and study particularly intensively the effects of excited states by a dedicated high precision computation. Moreover, we carry out a first computation with four dynamical flavors. Another aspect of this thesis is a feasibility study of a lattice QCD computation of the scalar quark content of the nucleon, which is an important element in the cross-section of a heavy particle with the nucleon mediated by a scalar particle (e.g. Higgs particle) and can therefore have an impact on Dark Matter searches. Existing lattice QCD calculations of this quantity usually have a large error and thus a low significance for phenomenological applications. We use a variance-reduction technique for quark-disconnected diagrams to obtain a precise result. Furthermore, we introduce a new stochastic method for the calculation of connected 3-point correlation functions, which are needed to compute nucleon structure observables, as an alternative to the usual sequential propagator method. In an explorative study we check whether this new method is competitive to the standard one. We use Wilson twisted mass fermions at maximal twist in all our calculations, such that all observables considered here have only O(a{sup 2}) discretization effects.

Nucleon structure from lattice QCD

International Nuclear Information System (INIS)

Dinter, Simon

2012-01-01

In this thesis we compute within lattice QCD observables related to the structure of the nucleon. One part of this thesis is concerned with moments of parton distribution functions (PDFs). Those moments are essential elements for the understanding of nucleon structure and can be extracted from a global analysis of deep inelastic scattering experiments. On the theoretical side they can be computed non-perturbatively by means of lattice QCD. However, since the time lattice calculations of moments of PDFs are available, there is a tension between these lattice calculations and the results from a global analysis of experimental data. We examine whether systematic effects are responsible for this tension, and study particularly intensively the effects of excited states by a dedicated high precision computation. Moreover, we carry out a first computation with four dynamical flavors. Another aspect of this thesis is a feasibility study of a lattice QCD computation of the scalar quark content of the nucleon, which is an important element in the cross-section of a heavy particle with the nucleon mediated by a scalar particle (e.g. Higgs particle) and can therefore have an impact on Dark Matter searches. Existing lattice QCD calculations of this quantity usually have a large error and thus a low significance for phenomenological applications. We use a variance-reduction technique for quark-disconnected diagrams to obtain a precise result. Furthermore, we introduce a new stochastic method for the calculation of connected 3-point correlation functions, which are needed to compute nucleon structure observables, as an alternative to the usual sequential propagator method. In an explorative study we check whether this new method is competitive to the standard one. We use Wilson twisted mass fermions at maximal twist in all our calculations, such that all observables considered here have only O(a 2 ) discretization effects.

Flavor extrapolation in lattice QCD

International Nuclear Information System (INIS)

Duffy, W.C.

1984-01-01

Explicit calculation of the effect of virtual quark-antiquark pairs in lattice QCD has eluded researchers. To include their effect explicitly one must calculate the determinant of the fermion-fermion coupling matrix. Owing to the large number of sites in a continuum limit size lattice, direct evaluation of this term requires an unrealistic amount of computer time. The effect of the virtual pairs can be approximated by ignoring this term and adjusting lattice couplings to reproduce experimental results. This procedure is called the valence approximation since it ignores all but the minimal number of quarks needed to describe hadrons. In this work the effect of the quark-antiquark pairs has been incorporated in a theory with an effective negative number of quark flavors contributing to the closed loops. Various particle masses and decay constants have been calculated for this theory and for one with no virtual pairs. The author attempts to extrapolate results towards positive numbers of quark flavors. The results show approximate agreement with experimental measurements and demonstrate the smoothness of lattice expectations in the number of quark flavors

Synthesis of spatially variant lattices.

Science.gov (United States)

Rumpf, Raymond C; Pazos, Javier

2012-07-02

It is often desired to functionally grade and/or spatially vary a periodic structure like a photonic crystal or metamaterial, yet no general method for doing this has been offered in the literature. A straightforward procedure is described here that allows many properties of the lattice to be spatially varied at the same time while producing a final lattice that is still smooth and continuous. Properties include unit cell orientation, lattice spacing, fill fraction, and more. This adds many degrees of freedom to a design such as spatially varying the orientation to exploit directional phenomena. The method is not a coordinate transformation technique so it can more easily produce complicated and arbitrary spatial variance. To demonstrate, the algorithm is used to synthesize a spatially variant self-collimating photonic crystal to flow a Gaussian beam around a 90° bend. The performance of the structure was confirmed through simulation and it showed virtually no scattering around the bend that would have arisen if the lattice had defects or discontinuities.

Carbon-13 magnetic relaxation rates or iron (III) complexes of some biogenic amines and parent compounds in aqueous solutions

International Nuclear Information System (INIS)

Lai, A.; Monduzzi, M.; Saba, G.

1980-01-01

Spin-lattice relaxation rates (R 1 ) from naturally occuring C-13 F.T. N.M.R. spectra of some catecholamines and parent compounds with Iron(III) at pD = 4 were determined in order to elucidate the molecular mechanism underlying their association in aqueous solutions. Complexation was observed only for catecholic ligands. The R 1 values were used to calculate iron-carbon scaled distances, and two complexation models were proposed where the catecholic function binds Fe(III) in the first and second coordination spheres respectively. The latter case was shown to be the consistent with the molecular geometries. (orig.)

A lattice approach to spinorial quantum gravity

Science.gov (United States)

Renteln, Paul; Smolin, Lee

1989-01-01

A new lattice regularization of quantum general relativity based on Ashtekar's reformulation of Hamiltonian general relativity is presented. In this form, quantum states of the gravitational field are represented within the physical Hilbert space of a Kogut-Susskind lattice gauge theory. The gauge field of the theory is a complexified SU(2) connection which is the gravitational connection for left-handed spinor fields. The physical states of the gravitational field are those which are annihilated by additional constraints which correspond to the four constraints of general relativity. Lattice versions of these constraints are constructed. Those corresponding to the three-dimensional diffeomorphism generators move states associated with Wilson loops around on the lattice. The lattice Hamiltonian constraint has a simple form, and a correspondingly simple interpretation: it is an operator which cuts and joins Wilson loops at points of intersection.

BInGaN alloys nearly lattice-matched to GaN for high-power high-efficiency visible LEDs

Science.gov (United States)

Williams, Logan; Kioupakis, Emmanouil

2017-11-01

InGaN-based visible light-emitting diodes (LEDs) find commercial applications for solid-state lighting and displays, but lattice mismatch limits the thickness of InGaN quantum wells that can be grown on GaN with high crystalline quality. Since narrower wells operate at a higher carrier density for a given current density, they increase the fraction of carriers lost to Auger recombination and lower the efficiency. The incorporation of boron, a smaller group-III element, into InGaN alloys is a promising method to eliminate the lattice mismatch and realize high-power, high-efficiency visible LEDs with thick active regions. In this work, we apply predictive calculations based on hybrid density functional theory to investigate the thermodynamic, structural, and electronic properties of BInGaN alloys. Our results show that BInGaN alloys with a B:In ratio of 2:3 are better lattice matched to GaN compared to InGaN and, for indium fractions less than 0.2, nearly lattice matched. Deviations from Vegard's law appear as bowing of the in-plane lattice constant with respect to composition. Our thermodynamics calculations demonstrate that the solubility of boron is higher in InGaN than in pure GaN. Varying the Ga mole fraction while keeping the B:In ratio constant enables the adjustment of the (direct) gap in the 1.75-3.39 eV range, which covers the entire visible spectrum. Holes are strongly localized in non-bonded N 2p states caused by local bond planarization near boron atoms. Our results indicate that BInGaN alloys are promising for fabricating nitride heterostructures with thick active regions for high-power, high-efficiency LEDs.

Vortex-Peierls States in Optical Lattices

International Nuclear Information System (INIS)

Burkov, A.A.; Demler, Eugene

2006-01-01

We show that vortices, induced in cold atom superfluids in optical lattices, may order in a novel vortex-Peierls ground state. In such a state vortices do not form a simple lattice but arrange themselves in clusters, within which the vortices are partially delocalized, tunneling between classically degenerate configurations. We demonstrate that this exotic quantum many-body state is selected by an order-from-disorder mechanism for a special combination of the vortex filling and lattice geometry that has a macroscopic number of classically degenerate ground states

The η' meson from lattice QCD

International Nuclear Information System (INIS)

Jansen, K.; Michael, C.; Urbach, C.

2008-04-01

We study the flavour singlet pseudoscalar mesons from first principles using lattice QCD. With N f =2 flavours of light quark, this is the so-called η 2 meson and we discuss the phenomenological status of this. Using maximally twisted-mass lattice QCD, we extract the mass of the η 2 meson at two values of the lattice spacing for lighter quarks than previously discussed in the literature. We are able to estimate the mass value in the limit of light quarks with their physical masses. (orig.)

Lattice polytopes in coding theory

Directory of Open Access Journals (Sweden)

Ivan Soprunov

2015-05-01

Full Text Available In this paper we discuss combinatorial questions about lattice polytopes motivated by recent results on minimum distance estimation for toric codes. We also include a new inductive bound for the minimum distance of generalized toric codes. As an application, we give new formulas for the minimum distance of generalized toric codes for special lattice point configurations.

Homogenization theory in reactor lattices

International Nuclear Information System (INIS)

Benoist, P.

1986-02-01

The purpose of the theory of homogenization of reactor lattices is to determine, by the mean of transport theory, the constants of a homogeneous medium equivalent to a given lattice, which allows to treat the reactor as a whole by diffusion theory. In this note, the problem is presented by laying emphasis on simplicity, as far as possible [fr

Hamiltonian approach to the lattice massive Schwinger model

International Nuclear Information System (INIS)

Sidorov, A.V.; Zastavenko, L.G.

1996-01-01

The authors consider the limit e 2 /m 2 much-lt 1 of the lattice massive Schwinger model, i.e., the lattice massive QED in two space-time dimensions, up to lowest order in the effective coupling constant e 2 /m 2 . Here, m is the fermion mass parameter and e is the electron charge. They compare their lattice QED model with the analogous continuous space and lattice space models, (CSM and LSM), which do not take account of the zero momentum mode, z.m.m., of the vector potential. The difference is that (due to extra z.m.m. degree of freedom) to every eigenstate of the CSM and LSM there corresponds a family of eigenstates of the authors lattice QED with the parameter λ. They restrict their consideration to small values of the parameter λ. Then, the energies of the particle states of their lattice QED and LSM do coincide (in their approximation). In the infinite periodicity length limit the Hamiltonian of the authors lattice QED (as well as the Hamiltonian of the LSM) possesses two different Hilbert spaces of eigenfunctions. Thus, in this limit the authors lattice QED model (as well as LSM) describes something like two connected, but different, worlds

The coupled cluster theory of quantum lattice systems

International Nuclear Information System (INIS)

Bishop, R.; Xian, Yang

1994-01-01

The coupled cluster method is widely recognized nowadays as providing an ab initio method of great versatility, power, and accuracy for handling in a fully microscopic and systematic way the correlations between particles in quantum many-body systems. The number of successful applications made to date within both chemistry and physics is impressive. In this article, the authors review recent extensions of the method which now provide a unifying framework for also dealing with strongly interacting infinite quantum lattice systems described by a Hamiltonian. Such systems include both spin-lattice models (such as the anisotropic Heisenberg or XXZ model) exhibiting interesting magnetic properties, and electron lattice models (such as the tJ and Hubbard models), where the spins or fermions are localized on the sites of a regular lattice; as well as lattice gauge theories [such as the Abelian U(1) model of quantum electrodynamics and non-Abelian SU(n) models]. Illustrative results are given for both the XXZ spin lattice model and U(1) lattice gauge theory

Relationships between lattice energies of inorganic ionic solids

Science.gov (United States)

Kaya, Savaş

2018-06-01

Lattice energy, which is a measure of the stabilities of inorganic ionic solids, is the energy required to decompose a solid into its constituent independent gaseous ions. In the present work, the relationships between lattice energies of many diatomic and triatomic inorganic ionic solids are revealed and a simple rule that can be used for the prediction of the lattice energies of inorganic ionic solids is introduced. According to this rule, the lattice energy of an AB molecule can be predicted with the help of the lattice energies of AX, BY and XY molecules in agreement with the experimental data. This rule is valid for not only diatomic molecules but also triatomic molecules. The lattice energy equations proposed in this rule provides compatible results with previously published lattice energy equations by Jenkins, Kaya, Born-Lande, Born-Mayer, Kapustinskii and Reddy. For a large set of tested molecules, calculated percent standard deviation values considering experimental data and the results of the equations proposed in this work are in general between %1-2%.

Bulk diffusion in a kinetically constrained lattice gas

Science.gov (United States)

Arita, Chikashi; Krapivsky, P. L.; Mallick, Kirone

2018-03-01

In the hydrodynamic regime, the evolution of a stochastic lattice gas with symmetric hopping rules is described by a diffusion equation with density-dependent diffusion coefficient encapsulating all microscopic details of the dynamics. This diffusion coefficient is, in principle, determined by a Green-Kubo formula. In practice, even when the equilibrium properties of a lattice gas are analytically known, the diffusion coefficient cannot be computed except when a lattice gas additionally satisfies the gradient condition. We develop a procedure to systematically obtain analytical approximations for the diffusion coefficient for non-gradient lattice gases with known equilibrium. The method relies on a variational formula found by Varadhan and Spohn which is a version of the Green-Kubo formula particularly suitable for diffusive lattice gases. Restricting the variational formula to finite-dimensional sub-spaces allows one to perform the minimization and gives upper bounds for the diffusion coefficient. We apply this approach to a kinetically constrained non-gradient lattice gas in two dimensions, viz. to the Kob-Andersen model on the square lattice.

On techniques of ATR lattice computation

International Nuclear Information System (INIS)

1997-08-01

Lattice computation is to compute the average nuclear constants of unit fuel lattice which are required for computing core nuclear characteristics such as core power distribution and reactivity characteristics. The main nuclear constants are infinite multiplying rate, neutron movement area, cross section for diffusion computation, local power distribution and isotope composition. As for the lattice computation code, WIMS-ATR is used, which is based on the WIMS-D code developed in U.K., and for the purpose of heightening the accuracy of analysis, which was improved by adding heavy water scattering cross section considering the temperature dependence by Honeck model. For the computation of the neutron absorption by control rods, LOIEL BLUE code is used. The extrapolation distance of neutron flux on control rod surfaces is computed by using THERMOS and DTF codes, and the lattice constants of adjoining lattices are computed by using the WIMS-ATR code. As for the WIMS-ATR code, the computation flow and nuclear data library, and as for the LOIEL BLUE code, the computation flow are explained. The local power distribution in fuel assemblies determined by the WIMS-ATR code was verified with the measured data, and the results are reported. (K.I.)

Full CKM matrix with lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Okamoto, Masataka; /Fermilab

2004-12-01

The authors show that it is now possible to fully determine the CKM matrix, for the first time, using lattice QCD. |V{sub cd}|, |V{sub cs}|, |V{sub ub}|, |V{sub cb}| and |V{sub us}| are, respectively, directly determined with the lattice results for form factors of semileptonic D {yields} {pi}lv, D {yields} Klv, B {yields} {pi}lv, B {yields} Dlv and K {yields} {pi}lv decays. The error from the quenched approximation is removed by using the MILC unquenced lattice gauge configurations, where the effect of u, d and s quarks is included. The error from the ''chiral'' extrapolation (m{sub l} {yields} m{sub ud}) is greatly reduced by using improved staggered quarks. The accuracy is comparable to that of the Particle Data Group averages. In addition, |V{sub ud}|, |V{sub ts}|, |V{sub ts}| and |V{sub td}| are determined by using unitarity of the CKM matrix and the experimental result for sin (2{beta}). In this way, they obtain all 9 CKM matrix elements, where the only theoretical input is lattice QCD. They also obtain all the Wolfenstein parameters, for the first time, using lattice QCD.

Topology optimization and lattice Boltzmann methods

DEFF Research Database (Denmark)

Nørgaard, Sebastian Arlund

This thesis demonstrates the application of the lattice Boltzmann method for topology optimization problems. Specifically, the focus is on problems in which time-dependent flow dynamics have significant impact on the performance of the devices to be optimized. The thesis introduces new topology...... a discrete adjoint approach. To handle the complexity of the discrete adjoint approach more easily, a method for computing it based on automatic differentiation is introduced, which can be adapted to any lattice Boltzmann type method. For example, while it is derived in the context of an isothermal lattice...... Boltzmann model, it is shown that the method can be easily extended to a thermal model as well. Finally, the predicted behavior of an optimized design is compared to the equiva-lent prediction from a commercial finite element solver. It is found that the weakly compressible nature of the lattice Boltzmann...

Bidirectional Fano Algorithm for Lattice Coded MIMO Channels

KAUST Repository

Al-Quwaiee, Hessa

2013-01-01

channel model. Channel codes based on lattices are preferred due to three facts: lattice codes have simple structure, the code can achieve the limits of the channel, and they can be decoded efficiently using lattice decoders which can be considered

Lattice solitons in Bose-Einstein condensates

International Nuclear Information System (INIS)

Efremidis, Nikolaos K.; Christodoulides, Demetrios N.

2003-01-01

We systematically study the properties of lattice solitons in Bose-Einstein condensates with either attractive or repulsive atom interactions. This is done, by exactly solving the mean-field Gross-Pitaevskii equation in the presence of a periodic potential. We find new families of lattice soliton solutions that are characterized by the position of the energy eigenvalue within the associated band structure. These include lattice solitons in condensates with either attractive or repulsive atom interactions that exist in finite or semi-infinite gaps, as well as nonlinear modes that exhibit atomic population cutoffs

Optical lattice on an atom chip

DEFF Research Database (Denmark)

Gallego, D.; Hofferberth, S.; Schumm, Thorsten

2009-01-01

Optical dipole traps and atom chips are two very powerful tools for the quantum manipulation of neutral atoms. We demonstrate that both methods can be combined by creating an optical lattice potential on an atom chip. A red-detuned laser beam is retroreflected using the atom chip surface as a high......-quality mirror, generating a vertical array of purely optical oblate traps. We transfer thermal atoms from the chip into the lattice and observe cooling into the two-dimensional regime. Using a chip-generated Bose-Einstein condensate, we demonstrate coherent Bloch oscillations in the lattice....

How to Share a Lattice Trapdoor

DEFF Research Database (Denmark)

Bendlin, Rikke; Peikert, Chris; Krehbiel, Sara

2013-01-01

We develop secure threshold protocols for two important operations in lattice cryptography, namely, generating a hard lattice Λ together with a "strong" trapdoor, and sampling from a discrete Gaussian distribution over a desired coset of Λ using the trapdoor. These are the central operations...... delegation, which is used in lattice-based hierarchical IBE schemes. Our work therefore directly transfers all these systems to the threshold setting. Our protocols provide information-theoretic (i.e., statistical) security against adaptive corruptions in the UC framework, and they are robust against up to ℓ...

Electronic properties of graphene antidot lattices

DEFF Research Database (Denmark)

Fürst, Joachim Alexander; Pedersen, Jesper Goor; Flindt, C.

2009-01-01

Graphene antidot lattices constitute a novel class of nano-engineered graphene devices with controllable electronic and optical properties. An antidot lattice consists of a periodic array of holes that causes a band gap to open up around the Fermi level, turning graphene from a semimetal...... into a semiconductor. We calculate the electronic band structure of graphene antidot lattices using three numerical approaches with different levels of computational complexity, efficiency and accuracy. Fast finite-element solutions of the Dirac equation capture qualitative features of the band structure, while full...

Synthetic magnetic fluxes on the honeycomb lattice

Energy Technology Data Exchange (ETDEWEB)

Gorecka, Agnieszka [Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore); Gremaud, Benoit [Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore); Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Laboratoire Kastler Brossel, Ecole Normale Superieure, CNRS, UPMC, 4 Place Jussieu, FR-75005 Paris (France); Miniatura, Christian [Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore); Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Institut Non Lineaire de Nice, UMR 6618, UNS, CNRS, 1361 Route des Lucioles, FR-06560 Valbonne (France); Institute of Advanced Studies, Nanyang Technological university, 60 Nanyang View, Singapore 639673 (Singapore)

2011-08-15

We devise experimental schemes that are able to mimic uniform and staggered magnetic fluxes acting on ultracold two-electron atoms, such as ytterbium atoms, propagating in a honeycomb lattice. The atoms are first trapped into two independent state-selective triangular lattices and then further exposed to a suitable configuration of resonant Raman laser beams. These beams induce hops between the two triangular lattices and make atoms move in a honeycomb lattice. Atoms traveling around each unit cell of this honeycomb lattice pick up a nonzero phase. In the uniform case, the artificial magnetic flux sustained by each cell can reach about two flux quanta, thereby realizing a cold-atom analog of the Harper model with its notorious Hofstadter's butterfly structure. Different condensed-matter phenomena such as the relativistic integer and fractional quantum Hall effects, as observed in graphene samples, could be targeted with this scheme.

Robots and lattice automata

CERN Document Server

Adamatzky, Andrew

2015-01-01

The book gives a comprehensive overview of the state-of-the-art research and engineering in theory and application of Lattice Automata in design and control of autonomous Robots. Automata and robots share the same notional meaning. Automata (originated from the latinization of the Greek word “αυτόματον”) as self-operating autonomous machines invented from ancient years can be easily considered the first steps of robotic-like efforts. Automata are mathematical models of Robots and also they are integral parts of robotic control systems. A Lattice Automaton is a regular array or a collective of finite state machines, or automata. The Automata update their states by the same rules depending on states of their immediate neighbours. In the context of this book, Lattice Automata are used in developing modular reconfigurable robotic systems, path planning and map exploration for robots, as robot controllers, synchronisation of robot collectives, robot vision, parallel robotic actuators. All chapters are...

Internal space decimation for lattice gauge theories

International Nuclear Information System (INIS)

Flyvbjerg, H.

1984-01-01

By a systematic decimation of internal space lattice gauge theories with continuous symmetry groups are mapped into effective lattice gauge theories with finite symmetry groups. The decimation of internal space makes a larger lattice tractable with the same computational resources. In this sense the method is an alternative to Wilson's and Symanzik's programs of improved actions. As an illustrative test of the method U(1) is decimated to Z(N) and the results compared with Monte Carlo data for Z(4)- and Z(5)-invariant lattice gauge theories. The result of decimating SU(3) to its 1080-element crystal-group-like subgroup is given and discussed. (orig.)

Anomalous diffusion in a dynamical optical lattice

Science.gov (United States)

Zheng, Wei; Cooper, Nigel R.

2018-02-01

Motivated by experimental progress in strongly coupled atom-photon systems in optical cavities, we study theoretically the quantum dynamics of atoms coupled to a one-dimensional dynamical optical lattice. The dynamical lattice is chosen to have a period that is incommensurate with that of an underlying static lattice, leading to a dynamical version of the Aubry-André model which can cause localization of single-particle wave functions. We show that atomic wave packets in this dynamical lattice generically spread via anomalous diffusion, which can be tuned between superdiffusive and subdiffusive regimes. This anomalous diffusion arises from an interplay between Anderson localization and quantum fluctuations of the cavity field.

Testing the holographic principle using lattice simulations

Directory of Open Access Journals (Sweden)

Jha Raghav G.

2018-01-01

Full Text Available The lattice studies of maximally supersymmetric Yang-Mills (MSYM theory at strong coupling and large N is important for verifying gauge/gravity duality. Due to the progress made in the last decade, based on ideas from topological twisting and orbifolding, it is now possible to study these theories on the lattice while preserving an exact supersymmetry on the lattice. We present some results from the lattice studies of two-dimensional MSYM which is related to Type II supergravity. Our results agree with the thermodynamics of different black hole phases on the gravity side and the phase transition (Gregory–Laflamme between them.

Phenomenology of Polymorphism, III: p, TDiagram and Stability of Piracetam Polymorphs

Science.gov (United States)

Céolin, R.; Agafonov, V.; Louër, D.; Dzyabchenko, V. A.; Toscani, S.; Cense, J. M.

1996-02-01

The nootropic drug Piracetam is known to crystallize in three phases. In order to obtain their stability hierarchy from sublimation pressure inequalities, the drawing of a topologicalp,Tdiagram was attempted. For such a purpose and also for quality control, crystallographic and thermodynamic data were required. Powder X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) were used. Molecular energy calculations were performed. Phase I melts at 426 K (ΔfusH(I) = +180 J·g-1). Phase II transforms into Phase I at 399 K (Δ(II→I)H= +24 J·g-1). Phase III transforms into phase I at 392 K (Δ(III→I)H= +28 J·g-1) or melts at 412 K (ΔfusH(III) = +210 J·g-1). Thep,Tdiagram shows that phase I is stable at higher temperature and phase II at lower temperature, like phase III, which is stable under high pressure. At room temperature, phase II is the more stable form, and phase I the less stable one. This agrees with the spontaneous I → II transformation observed at 298 K within a few hours, and with lattice energies, calculated previously. Molecular energy calculations and crystal structure comparison show how intermolecular hydrogen bonds and H-bonded dimers, in phases II and III, may stabilize conformations higher in energy than those of the isolated molecule and of phase I.

Evaluation of physical structure value in spring-harvested grass/clover silage and hay fed to heifers

DEFF Research Database (Denmark)

Schulze, A.K.S.; Nørgaard, P.; Byskov, M.V.

2015-01-01

The physical structure value of conserved grass/clover forages of spring harvest was evaluated by assessing effects of harvest time, conservation method, iNDF/NDF ratio and NDF intake (NDFI) per kg BW on chewing activity and fecal particle size in dairy heifers. A mixed sward consisting of ryegrass...... of 315, 436, 414 and 503 g/kg DM, respectively. Forages were fed as sole feed to four Jersey heifers of 435±30 kg BW in a 4×4 Latin square experiment. Feeding level was 90% of individual ad libitum intake, divided equally across two daily meals offered at 0800 and 1530 h. Chewing activity was estimated...... from recorded jaw movements (JM) oscillations continuously logged for 96 h and summarized per 24 h as mean effective rumination time and eating time. Eating behavior was further observed during four 20-min test meals. Weight proportion of large feces particles (>1.0 mm) and geometric mean fecal...

Recursive evaluation of space-time lattice Green's functions

International Nuclear Information System (INIS)

De Hon, Bastiaan P; Arnold, John M

2012-01-01

Up to a multiplicative constant, the lattice Green's function (LGF) as defined in condensed matter physics and lattice statistical mechanics is equivalent to the Z-domain counterpart of the finite-difference time-domain Green's function (GF) on a lattice. Expansion of a well-known integral representation for the LGF on a ν-dimensional hyper-cubic lattice in powers of Z −1 and application of the Chu–Vandermonde identity results in ν − 1 nested finite-sum representations for discrete space-time GFs. Due to severe numerical cancellations, these nested finite sums are of little practical use. For ν = 2, the finite sum may be evaluated in closed form in terms of a generalized hypergeometric function. For special lattice points, that representation simplifies considerably, while on the other hand the finite-difference stencil may be used to derive single-lattice-point second-order recurrence schemes for generating 2D discrete space-time GF time sequences on the fly. For arbitrary symbolic lattice points, Zeilberger's algorithm produces a third-order recurrence operator with polynomial coefficients of the sixth degree. The corresponding recurrence scheme constitutes the most efficient numerical method for the majority of lattice points, in spite of the fact that for explicit numeric lattice points the associated third-order recurrence operator is not the minimum recurrence operator. As regards the asymptotic bounds for the possible solutions to the recurrence scheme, Perron's theorem precludes factorial or exponential growth. Along horizontal lattices directions, rapid initial growth does occur, but poses no problems in augmented dynamic-range fixed precision arithmetic. By analysing long-distance wave propagation along a horizontal lattice direction, we have concluded that the chirp-up oscillations of the discrete space-time GF are the root cause of grid dispersion anisotropy. With each factor of ten increase in the lattice distance, one would have to roughly

Lattice formulation of a two-dimensional topological field theory

International Nuclear Information System (INIS)

Ohta, Kazutoshi; Takimi, Tomohisa

2007-01-01

We investigate an integrable property and the observables of 2-dimensional N=(4,4) topological field theory defined on a discrete lattice by using the 'orbifolding' and 'deconstruction' methods. We show that our lattice model is integrable and, for this reason, the partition function reduces to matrix integrals of scalar fields on the lattice sites. We elucidate meaningful differences between a discrete lattice and a differentiable manifold. This is important for studying topological quantities on a lattice. We also propose a new construction of N=(2,2) supersymmetric lattice theory, which is realized through a suitable truncation of scalar fields from the N=(4,4) theory. (author)

Temperature-dependent errors in nuclear lattice simulations

International Nuclear Information System (INIS)

Lee, Dean; Thomson, Richard

2007-01-01

We study the temperature dependence of discretization errors in nuclear lattice simulations. We find that for systems with strong attractive interactions the predominant error arises from the breaking of Galilean invariance. We propose a local 'well-tempered' lattice action which eliminates much of this error. The well-tempered action can be readily implemented in lattice simulations for nuclear systems as well as cold atomic Fermi systems

Random elements on lattices: Review and statistical applications

Science.gov (United States)

Potocký, Rastislav; Villarroel, Claudia Navarro; Sepúlveda, Maritza; Luna, Guillermo; Stehlík, Milan

2017-07-01

We discuss important contributions to random elements on lattices. We relate to both algebraic and probabilistic properties. Several applications and concepts are discussed, e.g. positive dependence, Random walks and distributions on lattices, Super-lattices, learning. The application to Chilean Ecology is given.