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The chiral light field has attracted great attention owing to its interaction with chiral matter. The generation of chiral light fields with rich structures has become crucial as it can expand application scenarios. Herein, we introduce a chiral optical vortex lattice. As a whole, the optical vortex lattice has a chiral intensity distribution, with each spiral arm having sub-vortices (chiral phase). By using an expansion factor to adjust the involute of a circular lattice, this helical optical vortex lattice can be continuously varied from a circular lattice. The chirality of intensity and phase can be controlled independently. Furthermore, the optical tweezers using the lattice demonstrate the capability of sub-vortices to manipulate particle movement, with the chiral intensity determining the trajectory of particle motion. As the lattice possesses both intensity and phase chirality, it may also find potential applications in tasks such as chiral structure microfabrication. [ABSTRACT FROM AUTHOR]

Nanocrystalline Cu2Cu1−xFexSnS4 (CCFTS) was prepared by a simple liquid-phase method. Physiochemical properties of the CCFTS powder as well as the CEs fabricated thereby were investigated using XRD, Raman spectroscopy, SEM, UV–Vis absorption, electrochemical impedance spectroscopy (EIS), etc. Conduction band shifts as well as the bandgap increases in the as-prepared CCFTS as a function of the Fe content were observed. For the dye-sensitized solar cells (DSSCs) with CCFTS counter electrodes (CEs), charge transfer impedance (Rct1) and short-circuit current (Jsc) were reduced by 64.54% and improved by 14.64%, respectively, compared with that with Fe-free Cu3SnS4 (CTS) CE. The enhancement of electron transfer through the CE/electrolyte interfaces stems from the optimal energy level alignment and the surface morphology tuned by the Fe alloying and hence improve the electrocatalytic activity of the CEs for the reduction from I3− to I−. As a consequence, photovoltaic conversion efficiency (PCE) of 6.95% was obtained which is 1.25 times that of the cell with Fe-free CTS CE. This work confirmed that element alloying into nanocrystalline transition metal compounds is effective for catalytic activity improvement. Material preparation reported herein is feasible, has high efficiency and low cost, and believed beneficial to high DSSCs development. [ABSTRACT FROM AUTHOR]

Unique wool-ball shaped nanocrystalline CoS was synthesized using solvothermal method in which dopamine (DA) was added as carbon source to combine with the CoS. The DA in situ polymerized and coated on the CoS particle surfaces during the solvothermal process. N, S co-doped carbon-encapsulated CoS(Co9S8) were achieved after a post carbonization. In the composites, CoS(Co9S8) nanocrystals and carbon are tightly bound and embedded into the amorphous carbon layer to form a spherical core–shell structure. Hybrid counter electrodes (CEs) fabricated with the product have good conductivity, dispersion and stability due to the synergetic effect between carbon and nanocrystalline CoS(Co9S8). Charge transfer through the CE/electrolyte interfaces is improved by dopamine-carbon combination. In the optimal case, PCE of 8.82% of the dye-sensitized solar cells (DSSCs) with the hybrid CEs was achieved, which is close to that of the cell with Pt (8.86%) CE, and is a 41.12% increase compared with that of CoS CE cell with the structure of photoanode/N719/electrolyte (I−/I3−)/CE. Moreover, stability of the cells with the composite CEs was greatly improved. The results demonstrate that the as-prepared composites are promising alternatives to Pt-CEs for high-performance DSSCs. The reported preparation method will guide further developments in highly efficient carbon-based catalysts for electrochemistry and energy related applications. [ABSTRACT FROM AUTHOR]

In order to explore the local corrosion mechanism of the riveted zone of aluminium-based skins under coating pre-damage, COMSOL Multiphysics was utilized to simulate a physico-chemical model with the laboratory test results of electrochemical parameters as boundary conditions. The time-domain variation of electrochemical behaviour parameters was analysed, and the dynamic corrosion characteristics in the riveted zone were revealed. Results show that after coating damage, with the simulation time going on from 0 day to 30 days, erosive ions continuously invade, and the corrosion reaction is gradually aggravated in the riveted zone, leading to a growth trend of the electrolytic electrode potential. At 30 days, the thickness of electrode deposits increases by 0.16 μm, and the electrolytic potential distribution ranges from 0.025 V to 0.028 V. By setting the electrolytic ion concentration in the coating pre-damage zone reasonably, the corrosion mechanism and morphology of the riveted zone of aluminium-based skins under different electrolyte concentrations can be explored, which can save laboratory check and verification time as well as improve work efficiency. [ABSTRACT FROM AUTHOR]

Pt counter electrodes (CEs) have been widely used in dye-sensitized solar cells (DSSCs) due to their high conductivity and electrocatalytic activity. However, industrialization of DSSCs is limited by shortcomings of Pt CEs such as being expensive, and weak corrosion resistance in electrolytes. Reported in this paper is two simple approaches to Pt-free Cu1.8S1−xSex CEs. Nanocrystalline Cu1.8S1−xSex CEs were fabricated via two processes, that is, a solvothermal process to Cu1.8S1−xSex powder followed by CE fabrication, and a solvothermal process and CE fabrication to Cu1.8S films followed by selenylation to Cu1.8S1−xSex CEs. Photoelectric conversion efficiencies (PCE) of 4.02% and 4.16% were achieved respectively by the as-fabricated Cu1.8S1−xSex CEs. Compared with the cells with Cu1.8S CEs fabricated by the same processes, increases of 19% and 45% were achieved, respectively. The PCE improvement comes from the enhancement of charge transfer at the CE/electrolyte interface induced by the selenylation of the CEs. [ABSTRACT FROM AUTHOR]

Self-amplified spontaneous emission in a free-electron laser has been proposed for the generation of very high brightness coherent x-rays. This process involves passing a high-energy, high-charge, short-pulse, low-energy-spread, and lowemittance electron beam through the periodic magnetic field of a long series of high-quality undulator magnets. The radiation produced grows exponentially in intensity until it reaches a saturation point. We report on the demonstration of self-amplified spontaneous emission gain, exponential growth, and saturation at visible (530 nanometers) and ultraviolet (385 nanometers) wavelengths. Good agreement between theory and simulation indicates that scaling to much shorter wavelengths may be possible. These results confirm the physics behind the self-amplified spontaneous emission process and forward the development of an operational x-ray free-electron laser., Generation of high-brightness (photon flux per frequency bandwidth per unit phase space volume) hard x-rays (photon energies greater than ~5 kev or wavelengths less than 2.5 A) has long been [...]

The hydrodynamic problem of the water entry of wedges with oblique velocity has been investigated numerically. The simulations of the interaction of the wedge and initial calm surface are carried out by solving the Reynolds-averaged Navier-Stokes equations (RANS). The overset mesh technique is introduced and the air-water interface is tracked using the method of Volume of Fluid (VOF). The water entries of wedges with various deadrise angles at different oblique velocities are simulated. A noticeable vortex flow and low pressure area on the leeward side of the wedge have been observed. The evolution of vortex and the pressure distribution over the wedge surface are analysed. The local vortex flow affects the local hydrodynamic pressure significantly. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Amblyopia or lazy eye is a common visual problem affecting children that cannot correct with lenses. Nitric oxide synthase (NOS) is a critical enzyme that regulates the activity of nitric oxide (NO), a key signaling molecule with multiple roles in many tissues. Among its many activities, NOS has been proposed to be required for normal eye development and altered NOS expression can lead to perturbations in eye development and vision. MATERIALS AND METHODS: To examine the potential role of neuronal NOS (nNOS) in vision loss, we generated a model of monocular deprivation amblyopia in rats. After suturing one eye, we examined several parameters of neural activity and nNOS expression in the retina 7, 14 and 28 days later. RESULTS: We found the rapid and progressive loss of neural activity in the retina of sutured eyes compared to non-treated and control eyes. The sutured eyes also showed decreased expression of nNOS at the protein and mRNA levels, indicating a strong correlation between nNOS expression and retina activity. CONCLUSIONS: These data suggest a potential role for nNOS activity in vision loss, opening potential avenues for therapeutic intervention. [ABSTRACT FROM AUTHOR]

The potato psyllid, Bactericera cockerelli (Sulc), vectors the pathogen "Canclidatus Liberibacter solanacearum" (Lso), causal agent of zebra chip disease of potato. Several cultivated and wild plants are reported to serve as alternate hosts for B. cockerelli and Lso, including silverleaf nightshade (SLN), a wild solanaceous woody perennial weed that occurs throughout Texas. Experiments were conducted in the laboratory to compare performance of Lso-infected and Lso-free B. cockerelli on SLN and potato. Results showed that host plants and Lso-infection significantly influenced the performance of B. cockerelli. Egg incubation and nymphal development of Lso-infected and Lso-free immatures were prolonged on SLN compared with potato indicating a host effect. Generally, Lso-infected B. cockerelli immatures developed faster on both SLN and potato, although significantly more Lso-free nymphs survived than nymphs that harbored the pathogen. Lso-free adults also lived longer and laid more eggs on potato than SLN. According to life table estimates, intrinsic and finite rates of increase of Lso-infected B. cockerelli were not significantly different from Lso-free individuals on potato and SLN. Analysis of the two factors revealed significant interaction effects between host and Lso and that development and reproduction of B. cockerelli is a function of both Lso-infection and host on which it fed. Results of this study suggests that Lso does not have a negative effect in the overall performance of B. cockerelli on both hosts and also demonstrated SLN to be an important alternative host that supports survival of Lsoinfected and Lso-free B. cockerelli populations. [ABSTRACT FROM AUTHOR]

OBJECTIVES: Ischemia/reperfusion (I/R) injury in the kidney during perioperative period remains the leading cause of acute renal failure. The purpose of this experimental study was to determine the role of dexmedetomidine (Dex) on renal I/R injury in rats. MATERIALS AND METHODS: Male Wistar rats, subjected to renal ischemia for 45 min, were either untreated or treated with dexmedetomidine 30 min prior to renal ischemia. A sham-operated group served as the control. Renal function [serum creatinine, blood urea nitrogen, serum Cystatin C and neutrophil gelatinase-associated lipocalin (NGAL)], histology, apoptosis and expression of the phosphorylations of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3) were assessed. RESULTS: The animals treated with dexmedetomidine improved renal functional recovery, especially reducing the level of serum Cystatin C and NGAL at early time after ischemia, attenuated histological lesions, reduced tubular epithelial apoptosis and inhibited the phosphorylation of JAK2 and its downstream molecule STAT3, contributing to ameliorating renal I/R injury. CONCLUSIONS: Our data suggest that antiapoptosis effect contributes to the renoprotection of dexmedetomidine, via inhibiting JAK2/STAT3 signaling pathway partially. [ABSTRACT FROM AUTHOR]

By integrating the interdigital structure into a conventional open-loop resonator, a compact mixed electric and magnetic coupling bandpass filter is designed and fabricated for the first time. Due to the high intensity inner coupling capacitor, which is generated by interdigital lines, not only did the size of the filter sharply decrease, but the electric field was strengthened. Therefore, by properly adjusting the ratio of electric and magnetic coupling, the transmission zeros very close to the passband is obtained readily. Based on mixed electric and magnetic coupling, a fourth-order bandpass filter with multiple transmission zeros is realized without requiring either a cross-coupled path or source-load coupling. For design purposes, the equivalent-circuit model is also derived and verified. Advantages of this filter include its miniaturized size of only 0.06λ0× 0.045λ0, its sharp cutoff slope, as well as the tiny discrepancies between simulation and measurement. [ABSTRACT FROM PUBLISHER]

C1/C2 organohalogens (organohalogens with one or two carbon atoms) can have significant environmental toxicity and ecological impact, such as carcinogenesis, ozone depletion and global warming. Natural halogenation processes have been identified for a wide range of natural organic matter, including soils, plant and animal debris, algae, and fungi. Yet, few have considered these organohalogens generated from the ubiquitous bacteria, one of the largest biomass pools on earth. Here, we report and confirm the formation of chloroform (CHCl3) dichloro-acetonitrile (CHCl2CN), chloral hydrate (CCl3CH(OH)2) and their brominated analogues by direct halogenation of seven strains of common bacteria and nine cellular monomers. Comparing different major C stocks during litter decomposition stages in terrestrial ecosystems, from plant litter, decomposed litter, to bacteria, we found increasing reactivity for nitrogenous organohalogen yield with decreasing C/N ratio. Our results raise the possibility that natural halogenation of bacteria represents a significant and overlooked contribution to global organohalogen burdens. As bacteria are decomposers that alter the C quality by transforming organic matter pools from high to low C/N ratio and constitute a large organic N pool, the bacterial activity is expected to affect the C, N, and halogen cycling through natural halogenation reactions. [ABSTRACT FROM AUTHOR]

C1/C2 organohalogens (organohalogens with one or two carbon atoms) can have significant environmental toxicity and ecological impact, such as carcinogenesis, ozone depletion and global warming. Natural halogenation processes have been identified for a wide range of natural organic matter, including soils, plant and animal debris, algae, and fungi. Yet, few have considered these organohalogens generated from the ubiquitous bacteria, one of the largest biomass pools on Earth. Here, we report and confirm the formation of chloroform (CHCl3) dichloro-acetonitrile (CHCl2CN), chloral hydrate (CCl3CH(OH)2) and their brominated analogues by direct halogenation of seven strains of common bacteria and nine cellular monomers. Comparing different major C stocks during litter decomposition stages in terrestrial ecosystems, from plant litter, decomposed litter, to bacteria, increasing reactivity for nitrogenous organohalogen yield was observed with decreasing C/N ratio. Our results raise the possibility that natural halogenation of bacteria represents a significant and overlooked contribution to global organohalogen burdens. As bacteria are decomposers that alter the C quality by transforming organic matter pools from high to low C/N ratio and constitute a large organic N pool, the bacterial activity is expected to affect the C, N, and halogen cycling through natural halogenation reactions. [ABSTRACT FROM AUTHOR]

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This paper mainly deals with the problem of target localization with unknown wall parameters for through-the-wall radar imaging (TWRI) applications. A novel approach is presented to correct the shift in target position due to the ambiguities of the wall parameters. This approach is based on imaging by using at least two assumed wall relative permittivities. For each assumed relative permittivity, a sequence of target images are obtained using different assumed wall thicknesses, and a linear trajectory is formed via Radon transform. The intersection of these linear trajectories corresponding to different assumed relative permittivities is the estimated target position. Besides, the estimated wall parameters are acquired to form the high-quality image. Simulation and experiment results show that the estimated target positions with the proposed approach are well consistent with the true target locations, and the high-quality images are generated with the estimated wall parameters. [ABSTRACT FROM AUTHOR]

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici, is the most devastating wheat disease in China. Although pathogens oversummering and overwintering in many regions of southwestern China have been studied, spore exchange among these regions is largely unknown. It is especially important to study the role of Sichuan, Yunnan, and Guizhou provinces in southwestern China in contributing to regional disease outbreaks in the major wheat-growing areas of China. Long-distance transport of P. striiformis f. sp. tritici urediniospores after oversummering and overwintering in Sichuan, Yunnan, and Guizhou was investigated using the HYSPLIT-4 model based on meteorological data. Results suggest that the pathogen spores can interchange frequently among Sichuan, Yunnan, and Guizhou in both spring and autumn. The sources of inoculum in Sichuan, Yunnan, and Guizhou have a high probability of impacting the epidemics in northern, northwestern, and southwestern China. In particular, disease epidemics in Guizhou can be affected not only by local inoculum but also by that from Yunnan in the spring. [ABSTRACT FROM AUTHOR]

Ten biological or ecological characteristics of pathogens/diseases were used to quantitatively describe 34 soybean (Glycine max) fungal diseases in the United States. These characteristics included optimal temperatures for disease development, host ranges, characteristics of disease cycle, and the pathogens' survival capacity. Gower's general similarity coefficients for pairs of diseases were determined and used in principal coordinate analysis (PCoA) to project the diseases into a two-dimensional space, in which significant patterns were identified for some of the characteristic variables, e.g., means of pathogen dispersal. Similarity coefficients indicated that soybean rust (Phakopsora pachyrhizi) resembled soybean downy mildew (Peronospora manshurica) and Leptosphaerulina leaf spot (Leptosphaerulina trifolii). Cluster analysis with multiscale bootstrapping identified two major clusters with high significance level (P > 0.95). In a loose cluster (P = 0.86), soybean rust was grouped with brown spot (Septoria glycines), frogeye leaf spot (Cercospora sojina), Phyllosticta leaf spot (Phyllosticta sojicola), purple seed stain (Cercospora kikuchii), downy mildew, and Leptosphaerulina leaf spot. Estimated soybean yield losses in the United States from 1996 to 2005 and the geographical distribution information of the diseases in this cluster implied that the potential geographical distribution range of soybean rust may include most U.S. soybean production regions and that yield losses would be light in the north but moderate in the south if environmental conditions are conducive. [ABSTRACT FROM AUTHOR]

In China, sandstorms play an important role in the long-range atmospheric transport and deposition of hexachlorobenzene (HCB). Concentrations of HCB in sandstorm depositions sampled from Beijing and the origination region were measured to reveal HCB levels during atmospheric transport. The results suggested a constant level of HCB during atmospheric transport. The values were close to environmental background values indicating that no potential source of HCB existed along the transport route. A tendency for HCB levels in Beijing to increase from north to east was also observed, which was probably due to the influence of wind speed and industrial zone distribution. [ABSTRACT FROM AUTHOR]

The effects of fluctuating soil temperature and water potential on sclerotial germination and apothecial production by Sclerotinia sclerotiorum were investigated in growth chamber experiments. In the temperature experiments, temperature fluctuations of 4, 8, 12, and 16°C around a median of 20°C, and a constant of 20°C, were tested. Daily temperature fluctuations of 8°C resulted in highest levels of sclerotial germination and apothecial production. The earliest appearance of apothecia occurred in the 8°C fluctuation treatment, 24 days after the start of the experiment. Sclerotia in the 12°C fluctuation treatment germinated last; its first sclerotium germinated 44 days after experiment initiation. For the soil water potential experiments, constant saturation (approximately -0.001 MPa) and three levels of soil water potential fluctuation from saturation—"low" (-0.03 to -0.04 MPa), "medium" (-0.06 to -0.07 MPa), and "high" (-0.09 to -0.1 MPa)—were tested. Constant saturation yielded the highest number of germinated sclerotia and apothecia. All soil water potential fluctuations were detrimental to sclerotial germination and apothecial production, with sclerotial germination under fluctuating moisture conditions less than a tenth of that occurring under constant saturation. The first sclerotium in the constant saturation treatment germinated in 35 days; however, 76 days were required in the high soil water potential fluctuation treatment. [ABSTRACT FROM AUTHOR]

This special report demonstrates the feasibility of long-term prediction of intercontinental dispersal of Phakopsora pachyrhizi spores, the causal agent of the devastating Asian soybean rust (SBR) that invaded the continental United States in 2004. The climate-dispersion integrated model system used for the prediction is the combination of the particle transport and dispersion model (HYSPLIT_4) with the regional climate prediction model (MM5). The integrated model system predicts the trajectory and concentration of P pachyrhizi spores based on three-dimensional wind advection and turbulent transport while incorporating simple viability criteria for aerial spores. The weather input of the model system is from a seasonal global climate prediction. The spore source strength and distribution were estimated from detected SBR disease severity and spread. The model system was applied to the known P. pachyrhizi spore dispersal between and within continents while focusing on the disease entry into the United States. Prediction validation using confirmed disease activity demonstrated that the model predicted the 2004 U.S. entry months in advance and reasonably forecast disease spread from the south coast states in the 2005 growing season. The model also simulated the dispersal from Africa to South America and from southern South America to Columbia across the equator. These validations indicate that the integrated model system, when furnished with detailed source distribution, can be a useful tool for P. pachyrhizi and possibly other airborne pathogen prediction. [ABSTRACT FROM AUTHOR]

Soybean rust, Phakopsora pachyrhizi, has been considered a threat to the production of the U.S. soybean, Glycine max. During the past decade, this disease gradually spread to Africa, South America, and recently to the United States. Previous soybean rust risk assessments with an assumption of availability of spores early in a season showed that weather conditions (dew and temperature) during a growing season, in general, are suitable for disease development in U.S. soybean-growing regions. Predicting the time of rust appearance in a field is critical to determining the destructive potential of rusts, including soybean rust. In this study, comparative epidemiology was used to assess likely rust incipient time in four locations within the U.S. Soybean Belt from south to north: Baton Rouge, LA; Charlotte, NC; Indianapolis, IN; and Minneapolis, MN. Temperature effects on the infection cycle of five rusts occurring in the Midwest were evaluated using a general disease model. The likely incipient times were examined with the modeling results. Among the rusts studied, early-appearing rusts had suitable conditions for development earlier in a season. However, a lag period of several weeks to more than 3 months was found from the time when conditions are suitable for a rust to develop or when hosts are available to the time when the rust was detected in fields. Length of the lag period differed among the rust species examined. If nature of long-distance dispersal is not significantly different among the rusts, implications of our study to the expected seasonal soybean rust incipience in fields lead to two possible scenarios: (i) average appearance time of soybean rust across the Soybean Belt should be somewhere between appearance times of common corn rust and southern corn rust, and (ii) with late appearance of the disease, late-planted soybean in the south has greater risk. [ABSTRACT FROM AUTHOR]

This article assesses the epidemic potential of soybean rust (Phakopsora pachyrhizi) in the United Slates. In the assessment, there are three critical components of uncertainty: (i) suitability of climate conditions in production areas for soybean rust epidemics; (ii) likelihood of establishment of the fungus in North America; and (iii) the seasonal dispersal potential of the pathogen from overwintering regions to major soybean production regions. Assessments on the first and second components suggest soybean rust epidemics are likely in the United States, and the certainty of the third component is yet to be determined. Comparison of epidemiological factors for soybean rust in soybean production regions between China and the United States shows a complicated picture with the United States having factors that both increase and decrease risk. Future investigation of risk components—incipience in the field and long-distance dispersal—is needed. [ABSTRACT FROM AUTHOR]

Soybean rust (Phakopsora pachyrhizi Sydow) has been known to occur in eastern Asia and Australia for decades. In recent years, the disease entered Africa and South America and has spread rapidly in these continents. It has become a concern to the U.S. soybean industry. To assess the threat of soybean rust, we used a modeling approach to determine the potential geographical zones where the fungus might overwinter and serve as source areas for seasonal epidemics. Long-term meteorological averages were used to assess the temperature stresses by using CLIMEX, and the dry stress with an algorithm developed in this study. Integration of stresses was used to predict the likelihood of survival of the rust in a defined location. Our results suggest that the new soybean rust invasions in Africa and South America occurred in the areas where the fungus might persist year-round. The main regions where rust has not been ~ported but might overwinter ate located in the western hemisphere, including northern South America, Central America, the Caribbean, Mexico, southern Texas, and Florida. Southeastern China and neighboring areas are suggested as the primary regions where initial spores for soybean rust epidemics in central China are produced. If the disease is to establish in the United States, it is likely to be restricted to parts of Florida and southern Texas during the winter in the frost-free areas or areas where the fungus could overcome short periods of below-freezing temperatures, Occurrence of rust epidemics within the U.S. soybean belt would depend on south-to-north dispersal of uredospores. [ABSTRACT FROM AUTHOR]

Presents a study that proposed a method for textile fabric three dimensional surface reconstruction using a photometric stereo method. Background of the photometric stereo method; Measurement of the wrinkle degree of the pattern; Analysis of the effectiveness of the method.

The development of new bone formation strategies offers tremendous therapeutic implications in a variety of musculoskeletal diseases. One approach involves harnessing the regenerative capacity of osteoprogenitor bone cells in combination with biomimetic scaffolds generated from appropriate scaffold matrices and osteoinductive factors. The aims of our study were to test the efficacy of two innovative osteoinductive agents: the osteoblast stimulating factor-1 (osf-1), an extracellular matrix-associated protein, and osteoinductive extracts of Saos-2 cells on human osteoprogenitor cells. Saos-2 extracted osteoinductive factors significantly stimulated alkaline phosphatase specific activity in basal and osteogenic conditions. Osf-1 significantly stimulated chemotaxis, total colony formation, alkaline phosphatase-positive colony formation, and alkaline phosphatase specific activity at concentrations as low as 10 pg/ml compared with control cultures. Osteoinductive factors present in Saos-2 cell extracts and osf-1 promoted adhesion, migration, expansion, and differentiation of human osteoprogenitor cells on 3-D scaffolds. The successful generation of 3-D biomimetic structures incorporating osf-1 or osteoinductive factors from Saos-2 cells indicates their potential for de novo bone formation that exploits cell-matrix interactions. [ABSTRACT FROM AUTHOR]

Historical data on wheat stem rust in the US and wheat leaf rust in Canada were analysed using a time-series approach to detect patterns in their long-term dynamics. Three sets of historical data were analysed, the first of which described the annual appearance of wheat-stem rust in six regions of the western Mississippi Basin from 1921 to 1961. Models developed from these data had significant autocorrelation components of AR(1) or AR(2), indicating that the date of disease appearance in 1 year was statistically related to the dates of appearance in the previous 1-2 years. The series of six regions were spatially significantly correlated with each other. Values of the cross-correlation coefficient increased from 0.20 to 0.83 as the distance between two regions decreased. The second data set represented relative diversity of physiological races of wheat stem rust from 1918 to 1982. Analysis suggested that a change in race diversity may occur in the US every 5-6 years based on AR(5) and AR(6) patterns. The third data set had two series on the phenotypes of leaf rust in the eastern and prairie regions of Canada. Analysis indicated that there was a 2-year autoregressive component AR(2) in each of these two time series. Analysis further suggested that the prairie population differed from the eastern population in having a 4-year moving average component, MA(4), in the majority of individual races. [ABSTRACT FROM AUTHOR]

Experiments were done in 1983, 1984 and 1985 in Beijing and Zhengzhou. People's Republic of China. to determine the relationship of yield components of wheat to the severity of yellow rust (Puccinia striiformis f.sp. tritici). Epidemics were manipulated by timing inoculation and fungicide applications. Disease, plant yield, number of ears per plant. number of grains per ear and 1000-grain weight were measured. Analysis indicated that there were interactions among the yield components. However, path coefficient analysis did not detect any statistically significant compensation and showed that there was a positive correlation among yield components The correlation coefficients between AUDPC (area under disease progress curve, accumulated to each growth stage) and each yield component increased gradually with growth stage, thus providing no evidence of a critical stage at which a yield component was most affected by disease. [ABSTRACT FROM AUTHOR]