A rule-based functional-structural model of rice considering source and sink functions

As a first step towards a generic genotype-phenotype model of rice, we present here a model of the growth and morphology of rice in combination with ecophysiological processes using the technique of functional-structural plant modelling (FSPM) and the interactive modelling platform GroIMP along with the graph-based Relational Growth Grammar formalism. The model constitutes a simple yet functionally coherent phenotype model of rice, consisting of a set of morphogenetic RGG rules describing an “average” developmental course and final morphology, partially linking yield traits to processes (tiller and grain number, stem length, grain filling rate, grain weight)

Public sector reforms, privatisation and regimes of control in a Chinese enterprise

The Chinese economic reform has recently become a major focus of attention around the world. The underlying rationale for the Chinese government's privatisation and public sector reforms is the view that reformed state enterprises and privately managed firms will demonstrate superior management control and better performance, and hence encourage economic growth and employment. There are very few intensive case studies published in English journals studying whether firms privatised in China have reversed previous losses and introduced better management controls, leading to increased investment, productivity, and overall organizational effectiveness and efficiency. The researchers do not seek to deny the control problems of Chinese SOEs, but question the consequences of the new controls installed during the post-privatisation period. The paper also reveals a declining tendency in employment; altered distributions of wealth ? especially to the state ? and labour, and a lack of improvements in the accountability of privatised companies. Overall, the paper argues, the aims of reform policies in China, including better control, increased profitability and an improved working life for Chinese people, have not materialized. The paper calls for more research on the above issues in the Chinese context

Techniques of replica symmetry breaking and the storage problem of the McCulloch-Pitts neuron

In this article the framework for Parisi's spontaneous replica symmetry breaking is reviewed, and subsequently applied to the example of the statistical mechanical description of the storage properties of a McCulloch-Pitts neuron. The technical details are reviewed extensively, with regard to the wide range of systems where the method may be applied. Parisi's partial differential equation and related differential equations are discussed, and a Green function technique introduced for the calculation of replica averages, the key to determining the averages of physical quantities. The ensuing graph rules involve only tree graphs, as appropriate for a mean-field-like model. The lowest order Ward-Takahashi identity is recovered analytically and is shown to lead to the Goldstone modes in continuous replica symmetry breaking phases. The need for a replica symmetry breaking theory in the storage problem of the neuron has arisen due to the thermodynamical instability of formerly given solutions. Variational forms for the neuron's free energy are derived in terms of the order parameter function x(q), for different prior distribution of synapses. Analytically in the high temperature limit and numerically in generic cases various phases are identified, among them one similar to the Parisi phase in the Sherrington-Kirkpatrick model. Extensive quantities like the error per pattern change slightly with respect to the known unstable solutions, but there is a significant difference in the distribution of non-extensive quantities like the synaptic overlaps and the pattern storage stability parameter. A simulation result is also reviewed and compared to the prediction of the theory.Comment: 103 Latex pages (with REVTeX 3.0), including 15 figures (ps, epsi, eepic), accepted for Physics Report

Identification of rice chromosome segment substitution line Z322-1-10 and mapping QTLs for agronomic traits from the F₃ population

Chromosome segment substitution lines (CSSLs) are powerful tools to combine naturally occurring genetic variants with favorable alleles in the same genetic backgrounds of elite cultivars. An elite CSSL Z322-1-10 was identified from advanced backcrosses between a japonica cultivar Nipponbare and an elite indica restorer Xihui 18 by SSR marker-assisted selection (MAS). The Z322-1-10 line carries five substitution segments distributed on chromosomes 1, 2, 5, 6 and 10 with an average length of 4.80 Mb. Spikilets per panicle, 1000-grain weight, grain length in the Z322-1-10 line are significantly higher than those in Nipponbare. Quantitative trait loci (QTLs) were identified and mapped for nine agronomic traits in an F3 population derived from the cross between Nipponbare and Z322-1-10 using the restricted maximum likelihood (REML) method in the HPMIXED procedure of SAS. We detected 13 QTLs whose effect ranging from 2.45% to 44.17% in terms of phenotypic variance explained. Of the 13 loci detected, three are major QTL (qGL1, qGW5-1 and qRLW5-1) and they explain 34.68%, 44.17% and 33.05% of the phenotypic variance. The qGL1 locus controls grain length with a typical Mendelian dominance inheritance of 3:1 ratio for long grain to short grain. The already cloned QTL qGW5-1 is linked with a minor QTL for grain width qGW5-2 (13.01%) in the same substitution segment. Similarly, the previously reported qRLW5-1 is also linked with a minor QTL qRLW5-2. Not only the study is important for fine mapping and cloning of the gene qGL1, but also has a great potential for molecular breeding

Hopping Conduction in Disordered Carbon Nanotubes

We report electrical transport measurements on individual disordered carbon nanotubes, grown catalytically in a nanoporous anodic aluminum oxide template. In both as-grown and annealed types of nanotubes, the low-field conductance shows as exp[-(T_{0}/T)^{1/2}] dependence on temperature T, suggesting that hopping conduction is the dominant transport mechanism, albeit with different disorder-related coefficients T_{0}. The field dependence of low-temperature conductance behaves an exp[-(xi_{0}/xi)^{1/2}] with high electric field xi at sufficiently low T. Finally, both annealed and unannealed nanotubes exhibit weak positive magnetoresistance at low T = 1.7 K. Comparison with theory indicates that our data are best explained by Coulomb-gap variable range hopping conduction and permits the extraction of disorder-dependent localization length and dielectric constant.Comment: 10 pages, 5 figure

Recurrence and Polya number of general one-dimensional random walks

The recurrence properties of random walks can be characterized by P\'{o}lya number, i.e., the probability that the walker has returned to the origin at least once. In this paper, we consider recurrence properties for a general 1D random walk on a line, in which at each time step the walker can move to the left or right with probabilities $l$ and $r$, or remain at the same position with probability $o$ ($l+r+o=1$). We calculate P\'{o}lya number $P$ of this model and find a simple expression for $P$ as, $P=1-\Delta$, where $\Delta$ is the absolute difference of $l$ and $r$ ($\Delta=|l-r|$). We prove this rigorous expression by the method of creative telescoping, and our result suggests that the walk is recurrent if and only if the left-moving probability $l$ equals to the right-moving probability $r$.Comment: 3 page short pape

The Influence of Solar Flares on the Lower Solar Atmosphere: Evidence from the Na D Absorption Line Measured by GOLF/SOHO

Solar flares presumably have an impact on the deepest layers of the solar atmosphere and yet the observational evidence for such an impact is scarce. Using ten years of measurements of the Na D$_{1}$ and Na D$_2$ Fraunhofer lines, measured by GOLF onboard SOHO, we show that this photospheric line is indeed affected by flares. The effect of individual flares is hidden by solar oscillations, but a statistical analysis based on conditional averaging reveals a clear signature. Although GOLF can only probe one single wavelength at a time, we show that both wings of the Na line can nevertheless be compared. The varying line asymmetry can be interpreted as an upward plasma motion from the lower solar atmosphere during the peak of the flare, followed by a downward motion.Comment: 13 pages, 7 figure

Density functional theory of phase coexistence in weakly polydisperse fluids

The recently proposed universal relations between the moments of the polydispersity distributions of a phase-separated weakly polydisperse system are analyzed in detail using the numerical results obtained by solving a simple density functional theory of a polydisperse fluid. It is shown that universal properties are the exception rather than the rule.Comment: 10 pages, 2 figures, to appear in PR

Constitutive Equations and Processing Maps for 49MnVS3 Non-Quenched and Tempered Steel

Flow stress variations of 49MnVS3 non-quenched and tempered steel are studied in isothermal compression tests on a Gleeble-1500D thermal simulated test machine at a deformation temperatures of 950, 1000, 1150, and 1200° C, and strain rates of 0.1, 1, 5, and 10 s⁻¹, with obtaining the strain hardening exponent n and deformation activation energy Q of the alloy. Thus, the constitutive equations and processing maps of compression flow behavior for 49MnVS3 non-quenched and tempered steel at high temperatures are established. It shows that the peak stress is shownto significantly reduced with a decrease in the strain rate and increase in deformation temperature when the alloy deforms at high temperature, and the deformation activation energy is 350.98 kJ/mol. When the true strain of 49MnVS3 non-quenched and microalloyed steel high-temperature deformation is 0.5, the optimum process parameters of the alloy are determined to be 1150–1200° C for the deformation temperature and 2–10 s⁻¹ for the strain rate, based on the criterion that the process parameters of higher power dissipation efficiency values should be chosen in the dynamic recrystallization region as the best processing technology.Изменение напряжения течения незакаленной и закаленной стали 49MnVS3 исследовали путем проведения испытаний на изотермическое сжатие на установке Gleeble-1500D, моделирующей высокотемпературные условия, при температурах деформации 950, 1000, 1150, 1200° C и скоростях деформации 0,1; 1; 5 и 10 c⁻¹ с показателем степени деформационного упрочнения n и значением энергии активации деформации сплава Q. Установлены определяющие уравнения и схемы обработки компрессионного режима течения для незакаленной и закаленной стали 49MnVS3 при высокой температуре. Анализ уравнений показал, что максимальное значение напряжения значительно уменьшается при снижении скорости деформации и повышении температуры деформации, если сплав подвергается деформации при высокой температуре, а значение энергии активации деформации составляет 350,98 кДж/моль. Если значения истинной деформации незакаленной стали 49MnVS3 и высокотемпературной деформации микролегированной стали составляют 0,5, то оптимальные параметры процесса обработки сплава определяются при температуре деформирования 1150…1200° C и скорости деформации 2…10 c⁻¹ на основе критерия, который способствует отбору параметров с более высокой эффективностью рассеивания мощности в области динамической рекристаллизации в качестве оптимальной технологии обработки.Зміну напруження течії незагартованої і загартованої сталі 49MnVS3 досліджували шляхом проведення випробувань на ізотермічний стиск на установці Gleeble-1500D, що моделює високотемпературні умови, за температур деформації 950, 1000, 1150, 1200° C та швидкості деформації 0,1; 1; 5 і 10 c⁻¹ із показником степеня деформаційного зміцнення n і значенням енергії активації деформації сплаву Q. Установлено визначальні рівняння і схеми обробки компресійного режиму течії для незагартованої і загартованої сталі 49MnVS3 за високої температури. Аналіз рівнянь показав, що максимальне значення напруження значно зменшується зі зниженням швидкості деформації і підвищенні температури деформації, якщо сплав зазнає деформації за високої температури, а значення енергії активації деформації дорівнює 350,98 кДж/моль. Якщо значення істинної деформації незагартованої сталі 49MnVS3 і високотемпературної деформації мікролегованої сталі дорівнюють 0,5, то оптимальні параметри процесу обробки сплаву визначаються за температури деформування 1150...1200° C і швидкості деформації 2...10 c⁻¹ на основі критерію, який сприяє відбору параметрів із більш високою ефективністю розсіяння потужності в області динамічної рекристалізації як оптимальної технології обробки

Exact Results on Potts Model Partition Functions in a Generalized External Field and Weighted-Set Graph Colorings

We present exact results on the partition function of the $q$-state Potts model on various families of graphs $G$ in a generalized external magnetic field that favors or disfavors spin values in a subset $I_s = \{1,...,s\}$ of the total set of possible spin values, $Z(G,q,s,v,w)$, where $v$ and $w$ are temperature- and field-dependent Boltzmann variables. We remark on differences in thermodynamic behavior between our model with a generalized external magnetic field and the Potts model with a conventional magnetic field that favors or disfavors a single spin value. Exact results are also given for the interesting special case of the zero-temperature Potts antiferromagnet, corresponding to a set-weighted chromatic polynomial $Ph(G,q,s,w)$ that counts the number of colorings of the vertices of $G$ subject to the condition that colors of adjacent vertices are different, with a weighting $w$ that favors or disfavors colors in the interval $I_s$. We derive powerful new upper and lower bounds on $Z(G,q,s,v,w)$ for the ferromagnetic case in terms of zero-field Potts partition functions with certain transformed arguments. We also prove general inequalities for $Z(G,q,s,v,w)$ on different families of tree graphs. As part of our analysis, we elucidate how the field-dependent Potts partition function and weighted-set chromatic polynomial distinguish, respectively, between Tutte-equivalent and chromatically equivalent pairs of graphs.Comment: 39 pages, 1 figur