bluuebunny/crossref_metadata_2025 huggingface dataset:
Manipulation of large molecules by low temperature STM
Authors: Moresco Francesca , Joachim Christian , Rieder Karl Heinz
Published: March 2004

The possibilities offered by low‐temperature scanning tunnelling microscopy to perform controlled manipulation of single atoms and small molecules and to build structures at the atomic scale have been extended recently to the manipulation of specially designed organic molecules. In this article, some recent applications of the manipulation techniques to large complex molecules are reviewed. Single porphyrin‐based molecules deposited on copper substrates have been manipulated by means of their interaction with the microscope tip. Manipulation of the molecules on Cu(211) offers the possibility to modify selective their internal conformation, realizing the principle of a conformational molecular switch. In a constant height mode of manipulation, the tunnelling current recorded during the process contains detailed information on the internal mechanics of the molecule when guided by the microscope tip. Copyright © 2004 John Wiley & Sons, Ltd.
Lorentz‐force‐induced excitation of cantilevers for oscillation‐mode scanning probe microscopy
Authors: Enders O. , Korte F. , Kolb H.‐A.
Published: March 2004

In the field of scanning probe microscopy, imaging modes with oscillating cantilevers are used to image soft samples with high resolution. The tapping mode is most frequently realized by a vibrating chip‐holder, which is coupled to the cantilever chip to excite the cantilever acoustically. A new promising approach is a direct excitation of a V‐shaped cantilever by a Lorentz force acting on the V‐shaped cantilever. The Lorentz force is generated by an alternating current flowing through the cantilever while being placed in a static magnetic field. Here we show an appropriate method, to microstructure the reflective coating of commercial cantilever chips for a current flow through the cantilever, that is based on a laser system. The laser microstructuring method allows chips to be processed without changing the mechanical properties of the cantilever itself, leading to excellent dynamic properties of the vibrating cantilever. Because the cantilever is excited directly, no peripheral resonances except the eigen‐resonance of the cantilever were apparent in the frequency spectrum. For a current of high amplitude at a static magnetic field of low intensity it is observed that the bimetal properties of the cantilever cause an additional thermal excitation. The results show that commercial cantilevers can be microstructured to implement this new excitation method for a frequency spectrum with a high‐quality factor of oscillation. Copyright © 2004 John Wiley & Sons, Ltd.
Nanomanipulation of single DNA molecules and its applications
Authors: Hu J. , Zhang Y. , Li B. , Gao H. B. , Hartmann U. , Li M. Q.
Published: March 2004

In this short review paper we briefly introduce recent results from our research work on the manipulation of single biological molecules deposited on the surface of mica by using scanning force microscopes: results of a cooperation between the Shanghai joint group and the University of Saarland on the manipulation of single DNA molecules and some possible applications based on single molecule manipulation and structural characterization. These results emanate from the Shanghai research teams in studying DNA molecular combing, cutting, pushing and pick‐up. Future prospects are briefly outlined. Copyright © 2004 John Wiley & Sons, Ltd.
Carrier density and confined polaron effects in the photoluminescence of fresh and oxidized porous silicon
Authors: Zou Bingsuo , Dai Jiahua , Xie Sishen
Published: March 2004

In this report the temperature‐dependent photoluminescence spectra, Fourier transform infrared (FTIR) spectra and time‐resolved FTIR spectra of freshly prepared porous silicon and oxidized porous silicon are examined. The experimental results indicate that there is a gradual transformation of electronic states with ageing in air, because ageing led to the surface oxidation and size reduction of Si nanostructures. This surface variation from hydrogen to oxygen during ageing leads to a red shift of the emissions. A clear quantum‐confinement effect exists for both H‐ and O‐capped porous silicon but the emissions in O‐capped porous silicon show clear polaronic nature. The photoinduced polaron is evidenced by the time‐resolved FTIR results. A reversible H‐detrapping process in silicon wafer occurs with temperature, which influences the conduction of silicon wafer and the photoluminescence of as‐prepared porous silicon due to the carrier density changes. Copyright © 2004 John Wiley & Sons, Ltd.
Characterization of delta‐doped B/Si multilayers by low‐energy secondary ion mass spectrometry
Authors: Liu R. , Wee A. T. S. , Shen D. H. , Takenaka Hisataka
Published: March 2004

Achieving a high depth resolution (of the order of 1 nm) is critical in the semiconductor industry today, and various methods have been developed to optimize depth resolution. Well characterized reference materials are also important in accurate quantitative analysis of doping profiles. International Standard Organization (ISO)/Technique Commission (TC201)/Surface Chemical Analysis (SC6‐SIMS) committees are engaged in the development of the international standardization of depth profiling of dopants in silicon using secondary ion mass spectrometry (SIMS). In this paper, the low‐energy primary ion O2+is employed in SIMS depth profiling of BN delta‐doped Si samples grown by magnetron sputtering to achieve high depth resolution and minimize the surface roughening. The11B+and30Si+yields were monitored in the depth profiles. Profiling using a 0.5 keV energy O2+beam is complicated by the early onset of surface roughening. The effects of oxygen flooding and sample rotation, used to suppress surface roughening, are also investigated. For analysis of the topography of the samples an atomic force microscope has been used. Copyright © 2004 John Wiley & Sons, Ltd.
Microstructures of magnetic nanoscale metallic multilayer and granular alloys with GMR effects
Authors: Lai Wuyan
Published: March 2004

Among the magnetic metallic multilayer and granular alloys displaying a giant magnetoresistance effect are a wide variety of inhomogeneous magnetic nanostructures. The two characteristic length scales in these systems—spin‐dependent electron mean free path and exchange coupling—vary from a few tens of nanometres to interatomic distances. Advanced methods for the characterization of surface and interface structures have been applied: x‐ray diffraction with a synchrotron radiation source; high‐resolution electron microscopy; field ion microscopy with an atom probe, etc. Some major achievements of research performed mainly at the Institute of Physics, Beijing, are reviewed with an emphasis on the roles of the interface structure and local morphology of nanoscale structures. For example, the structure of the nano‐oxide layers and its physical mechanism in an advanced specular giant magnetoresistance spin valve are characterized. The morphology of the nanoscaled granules has been determined directly in a CuCo granular alloy with giant magnetoresistance effects. The columnar crystallites in the multilayers, which is a very general phenomenon, were confirmed. Copyright © 2004 John Wiley & Sons, Ltd.
Surface smoothing of single‐crystal diamond by high‐speed cluster impacts with and without reactive erosion
Authors: Krämer Ralf , Yamaguchi Yasutaka , Gspann Jürgen
Published: March 2004

The smoothness of cluster‐eroded surfaces of natural and synthetic diamond (Monodite) is compared after erosion with high‐speed CO2 as well as Ar cluster beams. The reactive accelerated cluster erosion (RACE) of the single‐crystal diamond substrates using CO2 clusters leads to a fourfold larger root‐mean‐square roughness than the erosion with non‐reactive Ar clusters. On the other hand, the erosion rate observed with the accelerated Ar clusters is lower by about the same factor than that observed with the accelerated CO2 clusters. Molecular dynamics calculations reveal corresponding differences already in the simulations of single cluster impacts. Copyright © 2004 John Wiley & Sons, Ltd.
Magnetic clusters and cluster agglomerations analysed by scanning force microscopy
Authors: von Blanckenhagen P. , Chao M. , Gröger R. , Koch Th. , Schimmel Th.
Published: March 2004

Magnetic and non‐magnetic clusters were studied with a scanning force microscope (SFM) equipped with a magnetic tip and a small electromagnet installed at the sample position. The clusters were deposited on freshly cleaved mica surfaces. Heights and diameters of the clusters were determined by analysis of SFM height images. The mean diameter/height ratios show strong differences for the three kind of clusters investigated, however the results are mainly determined by the precisely measured cluster heights. The tip‐sample interaction was analysed by application of the force‐volume mode of operation of the SFM. The comparison of the interaction measured at room temprature on top of different sized cluster agglomerations at different magnetic fields and on the bare substrate surface yielded information on the magnetic state of the cluster systems. Results for magnetic Fe‐ and γ‐Fe2O3 clusters were compared with results for non‐magnetic ZrO2 clusters. The direct influence of the magnetic field at the sample position on the position of the magnetized tip and of the sample temperature increase due to the magnet current on the SFM results are analyzed and separated experimentally by adjusting appropriate parameters and by subtracting data taken with different parameters.

Agglomerations of Fe clusters behaved like systems of soft magnets at temperatures below the blocking temperatures of the systems, whereas those of γ‐Fe2O3 clusters showed superparamagnetic behaviour.

The results of this studies indicate that by enable a controlled variation of the sample temprature magnetic phase transitions of cluster systems could be explored in situ as a function of the size of agglomerations by application of scanning probe microscopy. Copyright © 2004 John Wiley & Sons, Ltd.
Mesoscopic phase transition of nanostructured materials: construction of computer experimental systems and synthesis and control of functional properties
Authors: Yamazaki Yoshitake , Gleiter Herbert , Lu Kunquan , Ou‐Yang Zhong‐can , Zhu Xing
Published: March 2004

Mesoscopic phase transitions and critical behaviour of nanostructured materials are discussed, together with the design of computer experimental systems and the synthesis and control of functional properties. The systems considered here have either two or three‐dimensional structural, magnetic or fractured character with nanometre‐sized grains and interfaces. The interactions are taken into account up to the third nearest neighbour by means of Lennard–Jones‐like potentials. The following problems are studied; how to investigate nanostructured materials, how to compute the metastable mesoscopic behaviour, and how to construct suitable computer experimental systems by Monte‐Carlo methods. The data obtained are reported in the form of fundamental theoretical and computational results of non‐equilibrium, local nanostructural properties. Copyright © 2004 John Wiley & Sons, Ltd.
Controlled structuring of mica surfaces with the tip of an atomic force microscope by mechanically induced local etching
Authors: Müller Matthias , Fiedler Thomas , Gröger Roland , Koch Thomas , Walheim Stefan , Obermair Christian , Schimmel Thomas
Published: March 2004

We demonstrate the controlled and reproducible structuring of surfaces of muscovite mica with the tip of an atomic force microscope operated in contact mode under ambient conditions. By repeated scanning of the tip along a predefined pattern on a cleaved mica surface at forces between 100 nN and 4 µN, mechanically induced etching was observed on the atomic scale. Using silicon nitride tips, no tip wear was observed during structuring. No debris was found on the surface as a result of the structuring process, indicating the atomic‐scale nature of the wear process. Line widths down to 3 nm were achieved, while at the same time patterns on a wide range of length scales between 5 nm and 100 µ m were generated reproducibly. The results can be explained by abrasive wear on the atomic scale due to sliding friction. The experiments allow the study of tribochemistry and abrasive wear on the atomic and molecular scale. At the same time, they represent an approach for high‐precision structuring of surfaces within a wide range of length scales. Copyright © 2004 John Wiley & Sons, Ltd.
Experiences implementing efficient Java thread serialization, mobility and persistence
Authors: Bouchenak S. , Hagimont D. , Krakowiak S. , De Palma N. , Boyer F.
Published: March 2004

Today, mobility and persistence are important aspects of distributed computing. They have many fields of use such as load balancing, fault tolerance and dynamic reconfiguration of applications. In this context, Java provides many useful mechanisms for the mobility of code via dynamic class loading, and the mobility or persistence of data via object serialization. However, Java does not provide any mechanism for the mobility/persistence of computation (i.e. threads).

We designed and implemented a new mechanism, calledJava thread serialization, that is used to build thread mobility or thread persistence. Therefore, a running Java thread can, at an arbitrary state of its execution, migrate to a remote machine where it resumes its execution, or be checkpointed on disk for possible subsequent recovery. With our services, migrating a thread is simply performed by the call of ourgoprimitive, and checkpointing/recovering a thread is performed by the call of ourstoreandloadprimitives.

Several projects have recently addressed the issue of Java thread serialization, e.g. Sumatra, Wasp, JavaGo, Brakes, JavaGoX, Merpati. Some of them have attempted to minimize the overhead incurred by the thread serialization mechanism on thread performance, but none of them has been able to completely avoid this overhead.

We propose a generic Java thread serialization mechanism that does not impose any performance overhead on serialized threads. This is achieved thanks to the use of type inference and dynamic de‐optimization techniques. In this paper, we describe the design and implementation details of our thread serialization prototype in Sun Microsystems' JDK. We report on experiments conducted with our prototype, present a comparative performance evaluation of the main thread serialization techniques, and confirm the elimination of the performance overhead with our thread serialization mechanism. Copyright © 2003 John Wiley & Sons, Ltd.
Evaluation and optimization of method calls in Java
Authors: Bellotti Francesco , Berta Riccardo , De Gloria Alessandro
Published: March 2004

Recent advances in Virtual Machine's technology have led to the diffusion of Java execution environments which provide performance levels comparable to those of traditional languages such as C/C++ and Fortran. This paper's focus is on method calls, a well researched area of compilers' optimization. In particular, we evaluate the impact on the performance of the Java virtual call mechanism and the advantages which can be obtained through the inlining optimization. Moreover, we propose a new heuristic methodology which allows us to consider whole sequences of methods for the inlining decision and not only simple couples of caller–callee methods.

The proposed methodology operates at bytecode level and is applicable only to the calls that can be resolved at compile time. Thus, we execute a devirtualization algorithm before the inlining decision, in order to enlarge the basis for the optimization.

We made empirical measures on three major platforms (Unix, Windows and Linux) by using the SPEC JVM98 benchmark suite. Results reveal an average performance improvement of 1.9% with devirtualization and 5.5% with inlining. We discuss the different behaviour of single benchmarks and virtual machines, arguing that dynamic compilers are not yet able to fully exploit the wider scope for intra‐procedural optimization offered by eliminating the calls. Finally, we show that taking into consideration whole sequences of calls—instead of single calls—is effective only on a few benchmarks where hotspots of execution involve cycles of nested methods. Copyright © 2003 John Wiley & Sons, Ltd.
Prospects for interregional correlations using Wisconsin and Holocene aridity episodes, northern Gulf of Mexico coastal plain
Authors: Otvos Ervin G.
Published: March 2004

Luminescence dating of extensive dune fields and associated eolian sandsheets provided a chronology of recently recognized Pleistocene and early Holocene dry climate episodes in the currently humid warm temperate northern–northeastern Gulf of Mexico region. Scattered parabolic dunes and clusters of intersecting parabolic dunes, along with elongated shore-transverse and shore-parallel dunes, developed. These landforms occur in a 390-km-long and 2- to 3-km-wide, semicontinuous belt in southeast Alabama and northwestern Florida. Dune elevations reach ± 22 m. Sangamon coastal barrier sectors were the primary source of the eolian sand. Deflation was coeval with early Wisconsin to mid-Holocene marine low sea-levels and associated distant shorelines. Early Holocene dune dates were synchronous, with indications of a hypsithermal dry interval in southeast Louisiana, the Yucatan, and the south Atlantic seaboard. Overlapping with dry episodes in Yucatan and the High Plains, Texas dunes and Louisiana and Texas prairie mounds, especially in the southwest Texas coast still dominated by dry climate, suggests intervals of early to late Holocene drought. The dates provide the basis for identifying and correlating Wisconsin, early, and late Holocene climate phases between currently semiarid and humid, coastal and interior areas. They contribute to future studies, including interregional paleoclimate modeling. Although Pleistocene coastal eolian deposition coincided with glaciation in the northern interior and with cooler temperatures of a reduced Gulf of Mexico, Holocene aridity phases may have been related to major variations in the position of high-pressure cells, storm tracks, and branches of the jet stream, and even to prolonged La Niña conditions.
Holocene hydrographical changes of the eastern Laptev Sea (Siberian Arctic) recorded in δ18O profiles of bivalve shells
Authors: Mueller-Lupp Thomas , Bauch Henning A. , Erlenkeuser Helmut
Published: March 2004

Oxygen isotope profiles along the growth axis of fossil bivalve shells of Macoma calcarea were established to reconstruct hydrographical changes in the eastern Laptev Sea since 8400 cal yr B.P. The variability of the oxygen isotopes (δ18O) in the individual records is mainly attributed to variations in the salinity of bottom waters in the Laptev Sea with a modern ratio of 0.50‰/salinity. The high-resolution δ18O profiles exhibit distinct and annual cycles from which the seasonal and annual salinity variations at the investigated site can be reconstructed. Based on the modern analogue approach oxygen isotope profiles of radiocarbon-dated bivalve shells from a sediment core located northeast of the Lena Delta provide seasonal and subdecadal insights into past hydrological conditions and their relation to the Holocene transgressional history of the Laptev Sea shelf. Under the assumption that the modern relationship between δ18Ow and salinity has been constant throughout the time, the δ18O of an 8400-cal-yr-old bivalves would suggest that bottom-water salinity was reduced and the temperature was slightly warmer, both suggesting a stronger mixture of riverine water to the bottom water. Reconstruction of the inundation history of the Laptev Sea shelf indicates local sea level ∼27 m below present at this time and a closer proximity of the site to the coastline and the Lena River mouth. Due to continuing sea level rise and a southward retreat of the river mouth, bottom-water salinity increased at 7200 cal yr B.P. along with an increase in seasonal variability. Conditions comparable to the modern hydrography were achieved by 3800 cal yr B.P.
Timing and intensity of groundwater movement during Egyptian Sahara pluvial periods by U-series analysis of secondary U in ores and carbonates
Authors: Osmond J.K. , Dabous Adel A.
Published: March 2004

Wet climatic episodes are known to have prevailed in the Egyptian Sahara several times during the late Quaternary, most recently during the Holocene 8000 yr ago. Earlier wet episodes have been recognized as having occurred during the past 300,000 yr and have been dated by U-series methods in speleothems and in lake travertines. We show here that the times of enhanced groundwater movement can also be determined by 230Th/234U dating of secondary U in ores of uranium, iron, and phosphate. We also present evidence that such acceleration of groundwater movements is indicated by relatively low 234U/238U activity ratios in the secondary uranium. Our new data show that pluvial periods in Egypt occurred during marine oxygen isotope stages 4, 5, 6, and 7 and therefore are consistent with the view that the wet episodes are the results of migration of the tropical monsoonal belt driven primarily by the 23,000-yr precession cycle of the Milankovich curve, modulated by the 100,000-yr eccentricity cycle.
Direct quantification of the rupture force of single hyaluronan/hyaluronan binding protein bonds
Authors: Liu Xuhui , Sun Jian Q. , Heggeness Michael H. , Yeh Ming-Long , Luo Zong-Ping
Published: March 2004

The non‐covalent bond between aggrecan and hyaluronan is critical for maintaining the normal structure and function of the extracellular matrix in articular cartilage. The failure of this bond can cause the loss of aggrecan and destruction of the extracellular matrix of articular cartilage. In this study, the rupture force of the single bond between hyaluronan and hyaluronan binding protein – the complex of the hyaluronan binding region of aggrecan and link protein – was directly measured with a nanomechanical testing system as 40±11 pN. The results were compared to a theoretical prediction based on a smart version of the Monte Carlo simulation.
Effect of salt and osmotic stress upon expression of the ethylene receptor ETR1 in Arabidopsis thaliana
Authors: Zhao Xue-Chu , Schaller G.Eric
Published: March 2004

In hormone perception, varying the concentrations of hormone, receptor, or downstream signaling elements can modulate signal transduction. Previous research has demonstrated that ethylene biosynthesis in plants is regulated by abiotic factors. Here we report that exposure of Arabidopsis plants to NaCl reduced expression of the ethylene receptor ETR1. The change in gene expression was reflected at the protein level based on immunoblot analysis. Further analysis supports a general effect of osmotic stress upon the expression level of ETR1. The reduction in ETR1 levels should cause increased sensitivity of the plant to ethylene. These results suggest that plant responses to abiotic stress are modulated by changes in the expression level of ethylene receptors.
The membrane topology of EmrE – a small multidrug transporter from Escherichia coli
Authors: Ninio Shira , Elbaz Yael , Schuldiner Shimon
Published: March 2004

EmrE is a multidrug transporter from Escherichia coli that belongs to the Smr family of small multidrug transporters. The secondary structure of EmrE consists of a four helical bundle, as judged by different techniques. EmrE has been extensively characterized; nevertheless, the membrane topology of EmrE has not been determined yet. Previous work with a homologous Smr protein provided partial information of the membrane topology, however the location of the carboxy‐terminus remained inconclusive. In this work we probed the membrane topology of EmrE, focusing on the carboxy‐terminus of the protein, using two independent approaches. Our results support a secondary structure where the carboxy‐terminus faces the cytoplasm, while the first loop faces the periplasm.
Mutation accumulation and the effect of copia insertions in Drosophila melanogaster
Authors: HOULE DAVID , NUZHDIN SERGEY V.
Published: March 2004

Repeated efforts to estimate the genomic deleterious mutation rate per generation (U) in Drosophila melanogaster have yielded inconsistent estimates ranging from 0·01 to nearly 1. We carried out a mutation-accumulation experiment with a cryopreserved control population in hopes of resolving some of the uncertainties raised by these estimates. Mutation accumulation (MA) was carried out by brother–sister mating of 150 sublines derived from two inbred lines. Fitness was measured under conditions chosen to mimic the ancestral laboratory environment of these genotypes. We monitored the insertions of a transposable element, copia, that proved to accumulate at the unusually high rate of 0·24 per genome per generation in one of our MA lines. Mutational variance in fitness increased at a rate consistent with previous studies, yielding a mutational coefficient of variation greater than 3%. The performance of the cryopreserved control relative to the MA lines was inconsistent, so estimates of mutation rate by the Bateman–Mukai method are suspect. Taken at face value, these data suggest a modest decline in fitness of about 0·3% per generation. The element number of copia was a significant predictor of fitness within generations; on average, insertions caused a 0·76% loss in fitness, although the confidence limits on this estimate are wide.
An improved formulation of marker heterozygosity in recurrent selection and backcross schemes
Authors: LUO Z. W. , MA L.
Published: March 2004

This report presents a theoretical formulation for predicting heterozygosity of a putative marker locus linked to two quantitative trait loci (QTL) in a recurrent selection and backcross (RSB) scheme. Since the heterozygosity at any given marker locus maintained in such a breeding programme reflects its map location relative to QTL, the present study develops the theoretical analysis of the QTL mapping method that recently appeared in the literature. The formulae take into account selection, recombination and finite population size during the multiple-generation breeding scheme. The single-marker and two-QTL model was compared numerically with the model involving two linked marker loci and two QTL. Without recombination interference, the two models predict the same expected heterozygosity at the linked marker loci, indicating that the model is valid for predicting marker heterozygosity maintained at any loci in an RSB breeding scheme. The formulation is demonstrated numerically for several RSB schemes and its implications in developing a likelihood-based statistical framework for modeling the RSB experiments are discussed.
Population subdivision and the Hudson–Kreitman–Aguade test: testing for deviations from the neutral model in organelle genomes
Authors: INGVARSSON PÄR K.
Published: March 2004

The Hudson–Kreitman–Aguade (HKA) test is based on the prediction from the neutral theory that levels of polymorphism within a species and the divergence between two closely related species should be correlated. Population subdivision has been shown to alter both the amounts of polymorphism segregating within species and the rate of divergence between species, meaning that genomic regions with different population structures also differ in their divergence to polymorphism ratios. Population subdivision may hence hamper the utility of the HKA test for detecting deviations from the standard neutral model, especially for organelle genomes that often have different patterns of population structure compared with nuclear genes. In this paper, I show that population subdivision inflates the number of instances where the HKA test detects deviations from the neutral model. Using coalescent simulations I show that this bias is most apparent when population subdivision is strong and differs substantially between the loci included. However, if divergence time is large and population structure substantial even changes in the levels of polymorphism and divergence associated with differences in the effective population size between two loci is enough to substantially alter the number of significant outcomes of the HKA test. A dataset on cytoplasmic diversity in Silene vulgaris and S. latifolia (Ingvarsson & Taylor, 2002) is also reanalysed. The previous study had shown a marked excess of intraspecific polymorphism in both species. However, when effects of population subdivision were removed, ad hoc, levels of intraspecific polymorphism were no longer significantly different from neutral expectations, suggesting that population subdivision contributed to the observed excess of intraspecific polymorphism seen in both species of Silene.
Isolation and characterization of dinucleotide repeat microsatellites in Drosophila ananassae
Authors: SCHUG M. D. , REGULSKI E. E. , PEARCE A. , SMITH S. G.
Published: March 2004

Drosophila ananassae is a cosmopolitan species with a geographic range throughout most of the tropical and subtropical regions of the world. Previous studies of DNA sequence polymorphism in three genes has shown evidence of selection affecting broad expanses of the genome in regions with low rates of recombination in geographically local populations in and around India. The studies suggest that extensive physical and genetic maps based on molecular markers, and detailed studies of population structure may provide insight into the degree to which natural selection affects DNA sequence polymorphism across broad regions of chromosomes. We have isolated 85 dinucleotide repeat microsatellite sequences and developed assay conditions for genotyping using PCR. The dinucleotide repeats we isolated are shorter, on average, than those isolated in many other Drosophila species. Levels of genetic variation are high, comparable to Drosophila melanogaster. The levels of variation indicate the effective population size of an Indonesian population of D. ananassae is 58692 (infinite allele model) and 217284 (stepwise mutation model), similar to estimates of effective population size for D. melanogaster calculated using dinucleotide repeat microsatellites. The data also show that the Indonesian population is in a rapid expansion phase. Cross-species amplification of the microsatellites in 11 species from the Ananassae, Elegans, Eugracilis and Ficusphila subgroups indicates that the loci may be useful for studies of the sister species, D. pallidosa, but will have limited use for more distantly related species.
Predicting Zn and Cu status in cereals – potential for a multiple regression model using soil parameters
Authors: LOMBNÆS P. , SINGH B. R.
Published: March 2004

Prediction of micronutrient deficiency normally involves soil extraction tests and correlations between soil extractable micronutrients and their concentration in plant tissues. The present study reports that the inclusion of soil properties in addition to soil extraction data represents a powerful tool for improving models for a simple determination of phytoavailable Zn and Cu. Soil and plant samples were collected in spring 2000 from 19 cereal fields in Central and Southeast Norway at sites with known micronutrient deficiency. Based on the sample information, the model approach used stepwise regression, applying actual plant Zn and Cu concentration as the response, and soil extractable Zn/Cu and physico-chemical properties of the soil as model predictors. A model involving citric acid extractable Zn coupled with selected soil properties could predict the concentration of Zn in plant tissues of barley and oats grown under field conditions with a significantly high precision (R2=0·96, P<0·001). The soil parameters included in the model, and their importance for phytoavailability of Zn, were in the order: citric acid extractable Zn>clay content>total Zn>pH>total C>total N. Inclusion of DTPA extractable Zn in the model, rather than citric acid, resulted in a slightly lower precision in the prediction of phytoavailable Zn (R2=0·86, P<0·001). A corresponding model for phytoavailable Cu, determined by DTPA and soil parameters, gave less precise prediction (R2=0·59, P<0·01). DTPA was more suitable for predicting phytoavailable Cu than citric acid. Plant Mn concentration could not be correlated to any of the extracting agents.
Effects of grain position on the panicle on starch biosynthetic enzyme activity in developing grains of rice cultivar Tainung 67 and its NaN3-induced mutant
Authors: JENG T. L. , WANG C. S. , CHEN C. L. , SUNG J. M.
Published: March 2004

The content of starch and the activities of enzymes involved in starch biosynthesis were examined in developing grains of field grown rice (Oryza sativa L.) plants. Enzyme activities were monitored throughout the grain filling period of cultivar Tainung 67 and its NaN3-induced mutant SA419. The activities of most of the grain enzymes involved in starch biosynthesis increased and reached their maxima during the initial period of grain development, then gradually declined towards the later stages of grain filling. Both Tainung 67 and SA419 showed different starch and amylose accumulation patterns in different grain positions. In cultivar Tainung 67, reduced activities of grain enzymes involved in starch biosynthesis, particularly during the early phase of grain filling, were related to the decreased starch accumulation for the grains located on proximal secondary branches as compared with the grains located on distal primary branches. The decreased amylose contents in the grains of Tainung 67 located on proximal secondary branches were attributable to their lower granule bound starch synthase and starch debranching enzyme activities at early and mid phases of grain filling. In mutant SA419, no significant changes were observed in the activities of grain enzymes involved in sucrose to starch conversion between the grains located on distal primary and proximal secondary branches of the panicle. As a result, grain setting position was found to have little effect on the contents of starch and amylose for these developing grains located on different branches. Thus, the mutant SA419 did have some agronomic and physiological traits that were superior to its wild type cultivar Tainung 67.
Phenology and growth response to irrigation and sowing date of Kabuli chickpea (Cicer arietinum L.) in a cool-temperate subhumid climate
Authors: ANWAR M. RAJIN , McKENZIE B. A. , HILL G. D.
Published: March 2004

The photothermal response of three Kabuli chickpea (Cicer arietinum L.) cultivars, at different growth stages, to eight irrigation treatments in 1998/99 and four irrigation treatments in 1999/2000 was studied on a Wakanui silt loam soil in Canterbury, New Zealand (43°38S, 172°30E). The rate of development from emergence to flowering (e-f) and sowing to harvest maturity were strongly and positively associated (R2=0·87, P<0·001) with mean temperature during those periods. All phenological stages considered (sowing to emergence, e-f, flowering to podding, podding to physiological maturity and physiological maturity to harvest maturity) depended upon accumulated thermal time (Tt) above a base temperature (Tb) of 1 °C.

An accurate prediction of time of flowering was made based on an accumulated mean Tt requirement of 629 °Cdays from e-f (R2=0·91, P<0·001). Fully irrigated crops had higher maximum dry matter accumulation (maxDM; 1093 g/m2), duration of exponential growth (DUR; 99 days), weighted mean absolute growth rate (WMAGR; 12·2 g/m2 per day) and maximum crop growth rate (MGR; 17·1 g/m2 per day). In 1998/99 the positive response of maxDM and MGR depended on a significant (P<0·01) interaction between irrigation and sowing date. The maxDM during the season was highly correlated with DUR and MGR (R2=0·79 and 0·65). It is concluded that to maximize chickpea biological yield in the dry season of the cool-temperate subhumid climate of Canterbury, irrigation should extend across all phenological stages.
Water-use efficiency and the effect of water deficits on crop growth and yield of Kabuli chickpea (Cicer arietinum L.) in a cool-temperate subhumid climate
Authors: ANWAR M. RAJIN , McKENZIE B. A. , HILL G. D.
Published: March 2004

The present study was conducted from 1998 to 2000, to evaluate seasonal water use and soil-water extraction by Kabuli chickpea (Cicer arietinum L.). The response of three cultivars to eight irrigation treatments in 1998/99 and four irrigation treatments in 1999/2000 at different growth stages was studied on a Wakanui silt loam soil in Canterbury, New Zealand. Evapotranspiration was measured with a neutron moisture meter and water use efficiency (WUE) was examined at crop maturity. Water use was about 426 mm for the fully irrigated treatment and at least 175 mm for the non-irrigated plants. There was a significant correlation (P<0·001) between water use and biomass yield (R2=0·80) and water use and seed yield (R2=0·75). There were also highly significant (P<0·001) interacting effects of irrigation, sowing date and cultivar on WUE and the trend was similar to that for seed yield. The estimated WUE ranged from 22–29 kg DM/ha per mm and 10–13 kg seed yield/ha per mm water use.

The three chickpea cultivars were capable of drawing water from depths greater than 60 cm. However, most of the water use (0·49–0·93 mm/10 cm soil layer per day) came from the top 0–30 cm, where most of the active roots were concentrated. The study has shown that using actual evapotranspiration and water-use efficiency, the biomass yield and seed yield of Kabuli chickpeas can be accurately predicted in Canterbury. Soil water shortage has been identified as a major constraint to increasing chickpea production. Drought was quantified using the concept of maximum potential soil moisture deficit (Dpmax) calculated from climate data. Drought responses of yield, phenology, radiation use efficiency and yield components were determined, and were highly correlated with Dpmax. The maximum potential soil moisture deficit increased from about 62 mm (irrigated throughout) to about 358 mm (dryland plots). Chickpea yield, intercepted radiation and the number of pods per plant decreased linearly as the Dpmax increased. Penman's irrigation model accurately described the response of yield to drought. The limiting deficit for this type of soil was c. 165 and 84 mm for the November and December sowings in 1998/99 and 170 mm in 1999/2000. Beyond these limiting deficits, yield declined linearly with maximum potential soil moisture deficits of up to 358 mm. There was little evidence to support the idea of a moisture sensitive period in these Kabuli chickpea cultivars. Yield was increased by irrigating at any stage of crop development, provided that the water was needed as determined by the potential soil moisture deficit and sowing early in the season.
The genetic control of flag leaf length in normal and late sown durum wheat
Authors: SHARMA S. N. , SAIN R. S. , SHARMA R. K.
Published: March 2004

Parental, F1, F2, BC1, BC2, BC11, BC12, BC21, BC22, BC1 self-pollinated and BC2 self-pollinated generations of three crosses involving six cultivars of durum wheat (Triticum turgidum var. durum) were studied for flag leaf length under normal and late sown environments to analyse the nature of gene effects. For most crosses the 10-parameter model was the best descriptor of the data to account for the variability in generation means of this trait but in cross HI 8062×JNK-4W-128 the 6-parameter model was the best (normal sown) while in cross Raj 911×DWL 5002 the 3-parameter model was the best (late sown). Of the epistatic interactions, dominance×dominance (l) and dominance×dominance×dominance (z) played significantly greater roles in controlling the inheritance of this trait. Absolute totals of non-fixable gene effects were much higher than the fixable gene effects in all the crosses in both the environments, indicating the greater roles of non-additive effects in controlling the inheritance of flag leaf length in durum wheat cultivars. Significant partial dominance was observed frequently in most of the crosses. Significant heterosis was attributed to combined effects of dominance×dominance (l), additive×additive×dominance (x) and dominance×dominance×dominance (z) epistatic interactions in the cross Cocorit 71×A-9-30-1 under late sown environment. Biparental mating and/or diallel selective mating, which exploit both fixable and non-fixable components, have been suggested for the improvement of this trait in durum wheat cultivars.
Effect of nitrogen, seed rate and plant growth regulator (chlormequat chloride) on the grain quality of oats (Avena sativa)
Authors: BROWNE R. A. , WHITE E. M. , BURKE J. I.
Published: March 2004

The physical parameters of oats of prime importance in determining milling quality are kernel content, the content of free kernels, hullability and screenings. In addition to screenings, hectolitre weight is used in the commercial trading of grain as an indicator of quality due to the absence of suitable methods, for commercial use, for determining the parameters that are closely related to milling quality. The effects of nitrogen (0–200 kg/ha), seed rate (200 and 300 seeds/m2) and plant growth regulator, chlormequat chloride, on grain quality were investigated at two locations, in one spring and three autumn sown experiments, in 1997/98 and 1998/99. Yields increased at higher rates of nitrogen and at the higher seed rate but were not significantly affected by chlormequat chloride. The effects of nitrogen rate and seed rate on kernel content were inconsistent but overall there was a small reduction at the higher nitrogen and higher seed rates and where chlormequat chloride was applied. In general, free kernels were reduced at the higher rates of nitrogen, at the higher seed rate and where chlormequat chloride was applied. Hullability improved at higher rates of nitrogen but was poorer at the higher seed rate and with chlormequat chloride. Screenings increased and hectolitre weight declined at the higher rates of nitrogen, the higher seed rate and with chlormequat chloride. The decline in hectolitre weight due to treatments within each experiment in general was associated with reductions in kernel content, content of free kernels and an increase in screenings. However, variation in hectolitre weight did not reflect variation in kernel content, free kernels and screenings between experiments. Overall, the changes in quality due to nitrogen rate, seed rate and chlormequat chloride were small compared with differences between varieties.
Effect of several germination conditions on total P, phytate P, phytase, acid phosphatase activities and inositol phosphate esters in spring and winter wheat
Authors: CENTENO C. , VIVEROS A. , BRENES A. , LOZANO A. , DE LA CUADRA C.
Published: March 2004

Changes in the wheat phosphatases (phytase-Phy and acid phosphatase-AcPh) and the degradation of their substrates (inositol phosphates esters) during seed germination have been examined in two studies. Germinated grains with high phytate degrading enzymes are of potential interest in the improvement of phosphorus availability in monogastric animals. In the first study, the seeds were soaked for 1 and 14 h and germinated for 3 and 5 days with and without the addition of gibberellic acid (GA3). In the second study, the seeds were soaked for 1 h and germinated for 1, 3 and 5 days with GA3. Phytase (up to 1800 and 1573 U/kg) and acid phosphatase (up to 13 115 and 10 154 U/g) activities and IP6 (6·96 and 7·67 mg/g), IP5 (0·40 and 0·60 mg/g) and IP4 (0·04 and 0·04 mg/g) were detected in ungerminated spring and winter wheat, respectively. The germination process caused a significant increase of Phy and AcPh activities in spring (up to 275 and 235%) and winter wheat (up to 250 and 329%) and a reduction in the phytate phosphorus content (up to 35 and 64%, respectively). Phytate phosphorus content was affected in both spring and winter wheat by the soaking time. Finally, during the course of germination, IP6 and IP5 were more rapidly degraded in winter wheat (62 and 62%) than in spring wheat (32 and 29%), and IP4 was only a short-living intermediate, which was increased during hydrolysis and degraded to IP3. In conclusion, the germination process caused a significant increase of Phy and AcPh in spring and winter wheat, which was accompanied with a significant reduction of phytate phosphorus content and an increase in the content of lower inositol phosphates.
Yield and P uptake by rice and wheat grown in a sequence as influenced by phosphate fertilization with diammonium phosphate and Mussoorie rock phosphate with or without crop residues and phosphate solubilizing bacteria
Authors: SHARMA S. N. , PRASAD R.
Published: March 2004

The field experiments were carried out at the Indian Agricultural Research Institute, New Delhi during 1996–97 to 1998–99 to study the effect of phosphate solubilizing bacteria (PSB) and incorporation of wheat and rice residue on the relative efficiency of diammonium phosphate (DAP) and Mussoorie rock phosphate (MRP) in three cycles of rice–wheat cropping system. Application of MRP had no significant effect on grain and straw yield and P uptake by rice and wheat; however, when it was inoculated with PSB, it increased grain and straw yields as well as P uptake of both rice and wheat. Efficiency of MRP+PSB was further increased when rice and wheat residues were incorporated and this practice made MRP on a par with DAP. Available P in soil after three cycles of rice–wheat cropping was more after MRP+PSB and incorporation of rice and wheat residues than after DAP. The results of the present study, therefore, indicate that low grade rock phosphate such as MRP can be advantageously utilized in rice–wheat cropping system when applied with PSB inoculation and incorporation of rice and wheat residues.
Abnormalities in growth, development and physiological responses to biotic and abiotic stress in potato (Solanum tuberosum) transformed with Arabidopsis ETR1
Authors: HAINES M. M. , SHIEL P. J. , FELLMAN J. K. , BERGER P. H.
Published: March 2004

Sprouted potato tubers lose nutritional value, and their increased content of reducing sugar renders them unsuitable for the french fry and chipping industries. Thus, tuber sprouting in storage is a primary concern of the potato industry, and is currently controlled by application of chemical sprout suppressants. Such suppressants are subject to widespread regulation by governmental agencies. The present study was initiated to investigate the role of the plant hormone ethylene in potato (Solanum tuberosum L.) tuber dormancy release. To this end, potato cv. ‘Russet Burbank’ was transformed with ETR1, an ethylene receptor gene from Arabidopsis. The resulting clones were genetically characterized to verify integration and expression of the ETR1 mRNA and protein. Transgenic clones showed developmental and morphologic changes in plant and tuber, and differing responses to environmental stress and pathogen attack relative to untransformed controls. Lengthening of dormancy was also observed in ETR1 antisense clones stored at 4 °C. Transgenic potato clones treated with solutions of silver thiosulfate (STS), an ethylene action inhibitor, showed restoration of normal plant morphology, while controls were unaffected. These results demonstrate the pleiotrophic effects of ethylene in potato, and identify a need for additional studies on the relationship between ethylene and tuber dormancy.
The Trading of Unlimited Liability Bank Shares in Nineteenth-Century Ireland: The Bagehot Hypothesis
Authors: HICKSON CHARLES R. , TURNER JOHN D.
Published: March 2004

In the mid-1820s, banks became the first businesses in Great Britain and Ireland to be allowed to form freely on an unlimited liability joint-stock basis. Walter Bagehot warned that their shares would ultimately be owned by widows, orphans, and other impecunious individuals. Another hypothesis is that the governing bodies of these banks, constrained by special legal restrictions on share trading, acted effectively to prevent such shares being transferred to the less wealthy. We test both conjectures using the archives of an Irish joint-stock bank. The results do not support Bagehot's hypothesis.