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H2A.Xis an H2A variant histone in eukaryotes, unique for its ability to respond to DNA damage, initiating the DNA repair pathway.H2A.Xreplacement within the histone octamer is mediated by the FAcilitates Chromatin Transactions (FACT) complex, a key chromatin remodeler. FACT is required for DEMETER (DME)-mediated DNA demethylation at certain loci inArabidopsis thalianafemale gametophytes during reproduction, though it is not known how FACT targets DME sites. Here, we investigated whether H2AX is involved in DME- and FACT-mediated DNA demethylation during Arabidopsis reproduction. We show thath2a.xmutants are more sensitive to genotoxic stress, consistent with previous reports.H2A.Xfused to theGreen Fluorescent Protein (GFP)gene under theH2A.Xpromoter was highly expressed in newly developingArabidopsistissues, including in male and female gametophytes. We examined DNA methylation inh2a.xdeveloping seeds using whole genome bisulfite sequencing, and found that CG DNA methylation in the developing endosperm, but not the embryo, is decreased genome-wide inh2a.xmutants, predominately in transposons and intergenic DNA. Hypomethylated sites overlapped 62 % with canonical DME loci. These data indicate that H2A.X is not required for DME function, but is important for DNA methylation homeostasis in the unique chromatin environment ofArabidopsisendosperm.

The nonconventional yeast Issatchenkia orientalis can grow under highly acidic conditions and has been explored for production of various organic acids. However, its broader application is hampered by the lack of efficient genetic tools to enable sophisticated metabolic manipulations. We recently constructed an episomal plasmid based on the autonomously replicating sequence (ARS) from Saccharomyces cerevisiae (ScARS) in I. orientalis and developed a CRISPR/Cas9 system for multiplexed gene deletions. Here we report three additional genetic tools including: (1) identification of a 0.8kb centromere-like (CEN-L) sequence from the I. orientalis genome by using bioinformatics and functional screening; (2) discovery and characterization of a set of constitutive promoters and terminators under different culture conditions by using RNA-Seq analysis and a fluorescent reporter; and (3) development of a rapid and efficient in vivo DNA assembly method in I. orientalis, which exhibited ~100% fidelity when assembling a 7kb-plasmid from seven DNA fragments ranging from 0.7kb to 1.7kb. As proof of concept, we used these genetic tools to rapidly construct a functional xylose utilization pathway in I. orientalis.

Significance Plant gene imprinting (allele-specific chromatin modification) results in parent-of-origin–dependent expression in endosperm, a nutritive tissue essential for embryo viability. Imprinted genes function in species reproductive isolation by causing embryo abortion in crosses. We analyzed the evolution of rice gene imprinting using four cultivars spanning domestication and the divergence of two subspecies 9,000 and 300,000 y ago, respectively. Most imprinted genes are imprinted across cultivars and enriched in regulatory functions. However, approximately 10% of imprinted genes have lost or gained imprinting, often associated with stably inherited epigenetic and genetic variation, suggesting a role in rice diversification. Our results highlight the role of transposable elements and epigenetic variation in shaping heritable changes in gene expression during rice evolution., Parent-of-origin–dependent gene expression in mammals and flowering plants results from differing chromatin imprints (genomic imprinting) between maternally and paternally inherited alleles. Imprinted gene expression in the endosperm of seeds is associated with localized hypomethylation of maternally but not paternally inherited DNA, with certain small RNAs also displaying parent-of-origin–specific expression. To understand the evolution of imprinting mechanisms in Oryza sativa (rice), we analyzed imprinting divergence among four cultivars that span both japonica and indica subspecies: Nipponbare, Kitaake, 93-11, and IR64. Most imprinted genes are imprinted across cultivars and enriched for functions in chromatin and transcriptional regulation, development, and signaling. However, 4 to 11% of imprinted genes display divergent imprinting. Analyses of DNA methylation and small RNAs revealed that endosperm-specific 24-nt small RNA–producing loci show weak RNA-directed DNA methylation, frequently overlap genes, and are imprinted four times more often than genes. However, imprinting divergence most often correlated with local DNA methylation epimutations (9 of 17 assessable loci), which were largely stable within subspecies. Small insertion/deletion events and transposable element insertions accompanied 4 of the 9 locally epimutated loci and associated with imprinting divergence at another 4 of the remaining 8 loci. Correlating epigenetic and genetic variation occurred at key regulatory regions—the promoter and transcription start site of maternally biased genes, and the promoter and gene body of paternally biased genes. Our results reinforce models for the role of maternal-specific DNA hypomethylation in imprinting of both maternally and paternally biased genes, and highlight the role of transposition and epimutation in rice imprinting evolution.

Significance The chromatin remodeling activities of the FACT (facilitates chromatin transactions) complex are required for many cellular functions, including transcription, DNA replication, and repair. Here, we demonstrate that the two FACT subunits, SSRP1 and SPT16, are also required for genome-wide DNA demethylation and regulation of gene imprinting during Arabidopsis reproduction. Without FACT, Arabidopsis seeds undergo abnormal development and exhibit aberrant DNA hypermethylation, including at imprinting control region loci. We show that FACT associates with the DEMETER (DME) DNA demethylase, facilitating DNA demethylation at over half of DME’s targets, specifically those which reside in heterochromatin. These results provide insight into upstream events in the DNA demethylation pathway and reveal the importance of chromatin remodeling for DNA demethylation during Arabidopsis reproduction., The DEMETER (DME) DNA glycosylase catalyzes genome-wide DNA demethylation and is required for endosperm genomic imprinting and embryo viability. Targets of DME-mediated DNA demethylation reside in small, euchromatic, AT-rich transposons and at the boundaries of large transposons, but how DME interacts with these diverse chromatin states is unknown. The STRUCTURE SPECIFIC RECOGNITION PROTEIN 1 (SSRP1) subunit of the chromatin remodeler FACT (facilitates chromatin transactions), was previously shown to be involved in the DME-dependent regulation of genomic imprinting in Arabidopsis endosperm. Therefore, to investigate the interaction between DME and chromatin, we focused on the activity of the two FACT subunits, SSRP1 and SUPPRESSOR of TY16 (SPT16), during reproduction in Arabidopsis. We found that FACT colocalizes with nuclear DME in vivo, and that DME has two classes of target sites, the first being euchromatic and accessible to DME, but the second, representing over half of DME targets, requiring the action of FACT for DME-mediated DNA demethylation genome-wide. Our results show that the FACT-dependent DME targets are GC-rich heterochromatin domains with high nucleosome occupancy enriched with H3K9me2 and H3K27me1. Further, we demonstrate that heterochromatin-associated linker histone H1 specifically mediates the requirement for FACT at a subset of DME-target loci. Overall, our results demonstrate that FACT is required for DME targeting by facilitating its access to heterochromatin.

We present a spatialization of digital library content based on item similarity and an experiment which compares the performance of this spatialization relative to a simple list-based display. Items in the library are elementary school, middle school, and high school science and engineering learning resources. Spatialization and visualization are accomplished through two-dimensional interactive Sammon mapping of pairwise item similarities computed from the joint occurrence of word bigrams. The 65 science teachers participating in the experiment were asked to search the library for curricular items they would consider using as part of one or more teaching assignments. The results indicate that whereas the spatializations adequately capture the salient features of the library’s content and teachers actively use them, item retrieval rates, task-completion time, and perceived utility do not significantly differ from the semantically poorer but easier to comprehend and navigate list-based representations. These results put into question the usefulness of the rapidly increasing supply of information spatializations.

Nanocrystalline undoped LiNbO 3 and LiNbO 3 doped with x % Fe ( x =0.5, 1, 2, 3, 5) were synthesized via a combustion method. Fe-doped LiNbO 3 with a 1 mol% doping concentration exhibited a room-temperature ferromagnetism of 0.06 emu/g. There was an abrupt change in properties when the doping concentration of Fe reached 2 mol%, where the lattice contracted obviously and the saturation magnetization ( M s ) increased an order of magnitude to 0.275 emu/g; M s slightly increased to its maximum value of 1.18 emu/g when the doping concentration was further increased to 5 mol%. Raman spectra showed that the substitution of Li by Fe occurred at small doping concentrations and the substitution of Nb at the Nb site occurred at higher doping concentrations. The results suggest that Fe 3+ replaced Nb Li 4+ first and the weaker ferromagnetism is due to the minor fraction of Nb Li 4+ in LiNbO 3 . Then, Fe 3+ substituted Li + , resulting in large lattice distortion and much stronger spin coupling of Fe–Nb. Finally, the excess Fe 3+ started to replace Nb 5+ at the Nb sites, where the spin coupling of Fe–Nb is weaker than that at the Li site. An analysis of the experimental results suggests that the congruent Fe-doped LiNbO 3 is a promising room-temperature single-phase multiferroic material.

A scheduling problem involving discrete controllable processing times is considered.The objectives are to minimize some scheduling criteria.We develop polynomial time algorithms for the considered problems.We further consider the NP-hard problem of the makespan case.An integer programming and a heuristic are presented to solve the NP-hard problem. In a manufacturing or service system, the actual processing time of a job can be controlled by the amount of an indivisible resource allocated, such as workers or auxiliary facilities. In this paper, we consider unrelated parallel-machine scheduling problems with discrete controllable processing times. The processing time of a job is discretely controllable by the allocation of indivisible resources. The planner must make decisions on whether or how to allocate resources to jobs during the scheduling horizon to optimize the performance measures. The objective is to minimize the total cost including the cost measured by a standard criterion and the total processing cost. We first consider three scheduling criterions: the total completion time, the total machine load, and the total earliness and tardiness penalties. If the number of machines and the number of possible processing times are fixed, we develop polynomial time algorithms for the considered problems. We then consider the minimization problem of the makespan cost plus the total processing cost and present an integer programming method and a heuristic method to solve the studied problem.

The DEMETER (DME) DNA glycosylase catalyzes genome-wide DNA demethylation and is required for endosperm genomic imprinting and embryo viability. Targets of DME-mediated DNA demethylation reside in small, euchromatic, AT-rich transposons and at the boundaries of large transposons, but how DME interacts with these diverse chromatin states is unknown. The STRUCTURE SPECIFIC RECOGNITION PROTEIN 1 (SSRP1), subunit of the chromatin remodeler FAcilitates Chromatin Transactions (FACT), was previously shown to be involved in the DME-dependent regulation of genomic imprinting in Arabidopsis endosperm. Therefore, to investigate the interaction between DME and chromatin, we focused on the activity of the two FACT subunits, SSRP1 and SUPPRESSOR of TY16 (SPT16), during reproduction in Arabidopsis. We find that FACT co-localizes with nuclear DME in vivo, and that DME has two classes of target sites, the first being euchromatic and accessible to DME, but the second, representing over half of DME targets, requiring the action of FACT for DME-mediated DNA demethylation genome-wide. Our results show that the FACT-dependent DME targets are GC-rich heterochromatin domains with high nucleosome occupancy enriched with H3K9me2 and H3K27me1. Further, we demonstrate that heterochromatin-associated linker histone H1 specifically mediates the requirement for FACT at a subset of DME-target loci. Overall, our results demonstrate that FACT is required for DME targeting by facilitating its access to heterochromatin.

Cu–Al–O thin films were deposited on glass substrates by radio frequency (RF) sputtering using an Al–Cu mosaic target under various RF powers at room temperature. The RF power was set at 100, 200, 250, and 300 W and the oxygen partial pressure (O2/Ar+O2) was set at 10%. This study examined the crystal structure, electronic structure, valence state, and electrical resistivity properties of the CuAlO2 thin films as a function of RF power and growth rate. The Cu/Al atomic ratios when the RF power was set at 100, 200, 250, and 300 W were 0.9, 1, 1.1, and 0.9, respectively. As RF power increased, the crystal structure of the Cu–Al–O film changed from amorphous to crystallized CuAlO2. In addition, the results also show that the growth rate could influence the phase formation behavior. The lowest resistivity of the Cu–Al–O thin films obtained in this study was 1.9 kΩ-cm with 250 W at room temperature.

Cu–Al–O thin films are deposited on (0001) sapphire substrates by radio-frequency sputtering using an Al–Cu mosaic target. The Cu/Al atomic ratio of as-deposited Cu–Al–O films is measured to be 1.1. After deposition, the Cu–Al–O films are annealed at 600, 800, and 1000 °C, respectively, for 1 h in a N 2 atmosphere. The film crystal structure, electronic structure, valence band, and electrical properties are studied. The as-deposited films are amorphous and films annealed at 600 °C contain the crystallized CuO phase; the structure becomes crystallized CuAlO 2 after annealing at 800 °C and 1000 °C. The 800 °C annealed film grows along the (00 l ) plane. The crystallization decreases with the growth of the (012) and (018) planes for films annealed at 1000 °C. The resistivity values of the 800 °C and 1000 °C annealed films were measured as 1.07 Ω-cm and 864.01 Ω-cm, respectively. The lower resistivity of the 800 °C annealed film is attributed to preferred (00 l ) growth orientation and a reduction of the energy band gap.

Cytosine DNA methylation regulates the expression of eukaryotic genes and transposons. Methylation is copied by methyltransferases after DNA replication, which results in faithful transmission of methylation patterns during cell division and, at least in flowering plants, across generations. Transgenerational inheritance is mediated by a small group of cells that includes gametes and their progenitors. However, methylation is usually analyzed in somatic tissues that do not contribute to the next generation, and the mechanisms of transgenerational inheritance are inferred from such studies. To gain a better understanding of how DNA methylation is inherited, we analyzed purified Arabidopsis thaliana sperm and vegetative cells—the cell types that comprise pollen—with mutations in the DRM, CMT2, and CMT3 methyltransferases. We find that DNA methylation dependency on these enzymes is similar in sperm, vegetative cells, and somatic tissues, although DRM activity extends into heterochromatin in vegetative cells, likely reflecting transcription of heterochromatic transposons in this cell type. We also show that lack of histone H1, which elevates heterochromatic DNA methylation in somatic tissues, does not have this effect in pollen. Instead, levels of CG methylation in wild-type sperm and vegetative cells, as well as in wild-type microspores from which both pollen cell types originate, are substantially higher than in wild-type somatic tissues and similar to those of H1-depleted roots. Our results demonstrate that the mechanisms of methylation maintenance are similar between pollen and somatic cells, but the efficiency of CG methylation is higher in pollen, allowing methylation patterns to be accurately inherited across generations.

Multivariate monitoring techniques for serially correlated observations have been widely used in various applications. This study examines several issues that have arisen in relation to the statistical quality control for the vector autoregressive (VAR) model, using a Monte Carlo approach. Different versions of the Hotelling T2 statistic and control limits to monitor the VAR-type process for both Phase I and Phase II schemes can be specified for different sample sizes and configurations of the model. Our simulation study suggests that the Hotelling's T2 statistic can be tested against the χ2 critical values during Phase I, but should be tested against scaled F critical values during Phase II. An unbiased covariance estimate of residuals is also recommended during Phase II when sample size is typically small. By reanalyzing some real data examples, the authors offer new conclusions. Copyright © 2012 John Wiley & Sons, Ltd.

Estimating the means and standard deviations of environmental data remains a great challenge because a substantial percentage of observations lies below or above detection limits. The inadequacy of several common, ad hoc estimation procedures is clear; this study instead proposes a robust moment estimation procedure for environmental data with a one-sided detection limit. The procedure assumes that the tails of the underlying distribution of the (transformed) data are symmetric, and censoring only occurs on one side. Through an application of the Renyi representation theorem, it is possible to use observations from the other side to learn the shape of the distribution below the detection limit, without specifying any particular parametric model, and consequently, derive the moment estimates of the distribution. A simulation provides a comparison of estimation performance between the proposed procedure and several existing estimators, and several real-life samples offer a good illustration.

A discrepancy measure to assess model fitness against a nonparametric alternative is proposed. First, a Polya tree prior is constructed so that the centering distribution is the null. Second, the prior is updated in the light of data to obtain the posterior centering distribution as the alternative. Third, a Kullback-Leibler divergence type of test statistic is derived to assess the discrepancy between the two centering distributions. The properties of the test statistic are derived, and a power comparison with several well-known test statistics is conducted. The use of the test statistic is illustrated using network traffic data.

Copper aluminum oxide (Cu-Al-O) film was prepared by radio-frequency (RF) sputter method using a pure metal Cu target and a mosaic target with different relation between Al and Cu at room temperature, respectively. The effects of Al content on crystal structure, electrical conductivity, and optical transmittance were studied. The composition of the film was adjusted by placing various numbers of Cu disks on the Al target surface. The Al concentration in the films were measured as 0, 4.2, 6.8, and 20.5 at.%, respectively. As the Al content in the deposited films increased, the crystal structure changed from CuO to amorphous CuAlO 2 and the resistivity of the deposited films increased. The resistivity of Cu-Al-O films obtained in this study ranged from 0.5 Ω-cm to 4.8 MΩ. The increased resistivity can be attributed to the incorporated Al 3+ ions substituting the Cu 2+ ions, thus decreasing the hole concentration. The average optical transmittances in the visible range (400–800 nm) of the deposited films were measured as 20.1%, 33%, 43.9%, and 73.9 % and the related optical band gaps obtained from optical transmittances were 2.1, 2.6, 2.7, and 2.9 eV, respectively.

We investigate the magnet effect of price limits using transaction data from the Taiwan Stock Exchange. A logit model incorporates explanatory variables from microstructure literature and reveals that the conditional probability of a price increase (decrease) increases significantly when the price approaches the upper (lower) price limit, in support of the magnet effect. Our approach recognizes when the magnet effect starts to emerge and identifies possible determinants of magnet effect. The probability of information-based trading has a significant impact on the magnet effect for lower price limits.

A censored stochastic volatility model is developed to reconstruct a return series censored by price limits, one popular form of market stabilization mechanisms. When price limits are reached, the observed prices are truncated and the equilibrium prices are unobservable, which makes further financial analyses difficult. The model offers theoretically sound estimates of censored returns and is demonstrated via simulations to outperform existing approaches with respect to the estimates of model parameters, unconditional means, and standard deviations. The algorithm is applied to model stock and futures returns and results are consistent with the simulation outcomes.

We develop in this article a data-analytic method to forecast the severity of next record insured loss to property caused by natural catastrophic events. The method requires and employs the knowledge of an expert and accounts for uncertainty in parameter estimation. Both considerations are essential for the task at hand because the available data are typically scarce in extreme value analysis. In addition, we consider three-parameter Gamma priors for the parameter in the model and thus provide simple analytical solutions to several key elements of interest, such as the predictive moments of record value. As a result, the model enables practitioners to gain insights into the behavior of such predictive moments without concerning themselves with the computational issues that are often associated with a complex Bayesian analysis. A data set consisting of catastrophe losses occurring in the United States between 1990 and 1999 is analyzed, and the forecasts of next record loss are made under various prior assumptions. We demonstrate that the proposed method provides more reliable and theoretically sound forecasts, whereas the conditional mean approach, which does not account for either prior information or uncertainty in parameter estimation, may provide inadmissible forecasts.

The impact of research and development (R&D) on firm performance is generally agreed to be positive, but the nature and extent of this impact share little agreement in the previous research. Using an improved, time series, cross-sectional regression model that accounts for both contemporaneous and firm-specific serial correlation, as well as the feedback between firm profitability and investments, our study compares the rate of return from a dollar investment on R&D to a dollar investment on fixed assets in pharmaceutical and chemical industries. We find positive associations of R&D intensity and all variables of firm performance (net margin, operating margin, sales growth, and market value). We find that an investment in R&D earns an operating margin return much higher than the industry cost of capital. We also find that the effect of an investment in R&D on the firm's market value is about twice as much the effect of an investment in fixed assets. These findings have implications for corporate investment strategies, indicating that additional R&D investment is more likely to provide a firm with a unique and sustainable competitive advantage.

Despite its importance for marketing channels research, the effect of interdependence on channel outcome variables remains elusive because of the inconsistent manner in which it is operationalized and the analytical methods used to assess its impact. To address those gaps, the authors first review prior approaches and identify the sources of their limitations. Then, the authors use the response surface approach (RSA) and derive three managerial insights that can be garnered from its use. They apply RSA to industrial distributor-supplier relationships and contrast it with previous methods. The empirical study results suggest that distributors perceive differential effects of supplier dependence and distributor dependence on outcome variables. The authors elaborate on managerial and research implications of the RSA results.

Examination of the tail behavior of a distribution F that generates teletraffic measurements is an important first step toward building a network model that explains the link between heavy tails and long-range dependence exhibited in such data. When knowledge of the tail behavior of F is vague, the family of the generalized Pareto distributions (GPDs) can be used to approximate the tail probability of F, and the value of its shape parameter characterizes the tail behavior. To detect tail behavior of F between two host computers on a network, the estimation procedure must be carried out over all possible combinations of host computers, and thus, the performance of the estimator under repeated use becomes the primary concern. In this article, we evaluate the long-run performance of several existing estimation procedures and propose a Bayes estimator to overcome some of the shortcomings. The conditions in which the procedures perform well in the long run are reported, and a simple rule of thumb for choosing an appropriate estimator for the task of repeated estimation is recommended.

Fe-doped LiNbO3 synthesized by the combustion method to seek new multiferroic materials exhibits room-temperature ferromagnetism, as reported in our previous work [1]. In this work, the defect structure of congruent and Fe-doped LiNbO3 (0.57–3.3 mol %) powders was investigated in detail by several methods. The molar ratio of [Li]/([Li]+[Nb]) was determined by the Curie temperature (Tc) via DSC. Two peaks of Tc were observed due to phase splitting [2], and the phase at lower Tc disappears as the Fe doping concentration increases. The coexistence of two different oxidation states of Fe ions in LiNbO3 was probed by XPS and UV-Vis spectroscopy. The Raman spectra exhibit displacements along the c axis of Li and Nb ions, and a deformation of the NbO6 framework owing to Fe doping. Several doping models were applied in the Rietveld refinement of powder X-ray diffraction collected by synchrotron radiation. The fitting by the Nb vacancy model leads to an improbably distorted structure of congruent LiNbO3. In Fe-doped LiNbO3, we conjecture that Li and Nb vacancies coexist in the lattice structure; Fe+2/Fe+3 ions are substituted for Li ions at the regular Li site and may push the anti-site NbLi ion back to the regular Nb site.

Background Crop plants such as rice, maize and sorghum play economically-important roles as main sources of food, fuel, and animal feed. However, current genome annotations of crop plants still suffer false-positive predictions; a more comprehensive registry of alternative splicing (AS) events is also in demand. Comparative genomics of crop plants is largely unexplored. Results We performed a large-scale comparative analysis (ExonFinder) of the expressed sequence tag (EST) library from nine grass plants against three crop genomes (rice, maize, and sorghum) and identified 2,879 previously-unannotated exons (i.e., novel exons) in the three crops. We validated 81% of the tested exons by RT-PCR-sequencing, supporting the effectiveness of our in silico strategy. Evolutionary analysis reveals that the novel exons, comparing with their flanking annotated ones, are generally under weaker selection pressure at the protein level, but under stronger pressure at the RNA level, suggesting that most of the novel exons also represent novel alternatively spliced variants (ASVs). However, we also observed the consistency of evolutionary rates between certain novel exons and their flanking exons, which provided further evidence of their co-occurrence in the transcripts, suggesting that previously-annotated isoforms might be subject to erroneous predictions. Our validation showed that 54% of the tested genes expressed the newly-identified isoforms that contained the novel exons, rather than the previously-annotated isoforms that excluded them. The consistent results were steadily observed across cultivated (Oryza sativa and O. glaberrima) and wild (O. rufipogon and O. nivara) rice species, asserting the necessity of our curation of the crop genome annotations. Our comparative analyses also inferred the common ancestral transcriptome of grass plants and gain- and loss-of-ASV events. Conclusions We have reannotated the rice, maize, and sorghum genomes, and showed that evolutionary rates might serve as an indicator for determining whether the identified exons were alternatively spliced. This study not only presents an effective in silico strategy for the improvement of plant annotations, but also provides further insights into the role of AS events in the evolution and domestication of crop plants. ExonFinder and the novel exons/ASVs identified are publicly accessible at http://exonfinder.sourceforge.net/. Electronic supplementary material The online version of this article (doi:10.1186/s12870-015-0431-7) contains supplementary material, which is available to authorized users.

In this study, the tail probability of a class of distributions commonly used in assessing the severity of insurance losses was examined. Without specifying any particular distribution, the use of an algebraic functional form Cx(-alpha) to approximate the tail behavior of the distributions in the class was demonstrated. Norwegian fire insurance data were examined, and the algebraic functional form was applied to derive the expected loss of a reinsurance treaty that covers all losses exceeding a retention limit. It was shown that (1) the expected loss is insensitive to the parameter alpha for a high retention limit (e.g., a catastrophe treaty), and (2) with a low retention limit (e.g., a largest claim treaty), a reliable estimate of the parameter alpha and a sound judgment on the maximum potential loss of the treaty could provide useful and defensible summary statistics for pricing the treaty. Thus, when dealing with the losses of certain reinsurance treaties, it was concluded that knowledge of a specific probability distribution is not critical, and the summary statistics derived from the model are robust with respect to a large class of loss distributions.

A forecasting model of next record value proposed by Hill [1] assumes the underlying distribution F(x) is of an algebraic functional form with a shape parameter α for large x. That is, 1 − F(x) ≃Cx −α, for large x. In this article, we extend his model by incorporating a three-parameter Gamma prior of α to derive analytical solutions of the predictive distribution and moments of X given that X is a new record value. These closed-form formulas can be represented as ratios of moments of Gamma distributions. We apply the proposed model to a real-life data set that consists of the insured property losses of 33 catastrophes caused by tropical storms in the United States in 1995. The example illustrates the importance of incorporating prior experience and accounting for uncertainty in parameter estimation when forecasting record values. Both considerations are the main ingredients in the development of the proposed model.

Risk managers are often concerned about tail probabilities of asset return distributions, in particular the frequency and severity of extreme returns. In this article, we propose a model that integrates extreme value theory and point processes to model the frequency and severity of exchange rate returns. The proposed model is applied to daily spot exchange rate series and the parameters of interest, such as the tail index, the mean size and rate of occurrence of extreme returns, are estimated using maximum likelihood estimation. We study the impact of recent currency crises on the frequency and severity of the series and find that, during 1995–9, the frequency of extreme daily Japanese yen–US dollar spot exchange rate returns increases twofold, and the time duration of high volatility persists longer for the Japanese yen series than for the Swiss franc and Danish krone series. Copyright © 2001 John Wiley & Sons, Ltd.

The implementation of the Hill estimator, which estimates the heaviness of the tail of a distribution, requires a choice of the number of extreme observations in the tails, r from a sample of size n where 2 ≤ r + 1 ≤ n. This article is concerned with a robust procedure of choosing an optimal r. Thus, an estimation procedure, δ s , based on the idea of spacing statistics, H(r) is developed. The proposed decision rule for choosing r under the squared error loss is found to be a simple function of the sample size. The proposed rule is then illustrated across a wide range of data, including insurance claims, currency exchange rate returns, and city size.

SummaryNucleosome remodelers of the DDM1/Lsh family are required for DNA methylation of transposable elements, but the reason for this is unknown. How DDM1 interacts with other methylation pathways, such as small-RNA-directed DNA methylation (RdDM), which is thought to mediate plant asymmetric methylation through DRM enzymes, is also unclear. Here, we show that most asymmetric methylation is facilitated by DDM1 and mediated by the methyltransferase CMT2 separately from RdDM. We find that heterochromatic sequences preferentially require DDM1 for DNA methylation and that this preference depends on linker histone H1. RdDM is instead inhibited by heterochromatin and absolutely requires the nucleosome remodeler DRD1. Together, DDM1 and RdDM mediate nearly all transposon methylation and collaborate to repress transposition and regulate the methylation and expression of genes. Our results indicate that DDM1 provides DNA methyltransferases access to H1-containing heterochromatin to allow stable silencing of transposable elements in cooperation with the RdDM pathway.

Rare earth metals are used in semiconductors, solar cells and catalysts. This review focuses on the background of oxide metallurgy technologies, the chemical and physical properties of rare earth (RE) metals, the background of oxide metallurgy, the functions of RE metals in steelmaking, and the influences of RE metals on steel microstructures. Future prospects for RE metal applications in steelmaking are also presented.

A vector autoregressive (VAR) model has become a popular multivariate monitoring technique for serially correlated observations often observed in practice. In this article, we examine, via a Monte Carlo approach, the effect of a shift in the model parameter and the sample size in both Phase I and Phase II schemes on control chart statistics, namely, different versions of Hotelling's T2 when a VAR model is employed. The effects are reported and specific T 2 statistics under various sample sizes is recommended.

An electrically switchable diffraction grating (ESDG) based on cholesteric liquid crystal (CLC) filled into the cell with slit electrodes is demonstrated in this study. On one hand, with low voltage, the ESDG has high second order diffraction efficiency because of the alternating planar and fingerprint textures. With high voltage, on the other hand, the ESDG has high first order diffraction efficiency because of the alternating planar and homeotropic textures. The first and second order diffraction efficiencies of ESDG are electrically swapped. The maximum diffraction efficiency of the ESDG is approximately 32% at each grating mode.

VOx films were deposited by radio-frequency reactive magnetron sputtering from a vanadium target at room temperature. Local atomic and electronic structures of the films were then modified by thermal annealing. The oxidation state and structural and gasochromic properties of the films were elucidated by X-ray absorption spectroscopy. Analytical results indicate that the as-deposited VOx films were amorphous with mixed V(4+) and V(5+) valences. The amorphous VOx had a disordered and expanded lamellar structure resembling that of polymer-intercalated V2O5 gels. VOx films were crystallized into orthorhombic V2O5 at 300 °C, and the lamellar structure was eliminated at 400 °C. Additionally, the gasochromic reaction reduced the vanadium valence via intervalence transitions between V(5+) and V(3+). Moreover, removing the lamellar structure reduced the gasochromic rate, and the gasochromic reaction transformed the V2O5 crystalline phase irreversibly into an H1.43V2O5 phase. Based on the results of this study, amorphous VOx with a lamellar structure is recommended for use in H2 gas sensors.

NiO films were deposited by radio-frequency reactive magnetron sputtering from a NiO target. A decomposition reaction was found as the films annealed at 400 °C in vacuum. The decomposition increased with increasing annealing temperature and the non-stoichiometry of the film. The electronic and atomic structure of the annealed films were further investigated by X-ray absorption near-edge structure (XANES) spectroscopy, and extended X-ray absorption fine structure (EXAFS) spectroscopy. The results show the decomposition of sputtered NiO is attributed to excess vacancies that formed during sputtering, which destroyed the atomic bonds in the NiO crystalline. The EXAFS results indicate that there is a transition stage of surplus Ni ions filling anion sites at the beginning of the decomposition reaction. The surplus Ni ions act as a link between the central atom and the Ni in the second shell, which may be responsible for the filamentary conducting paths proposed in resistive random access memory (ReRAM).

The effective prioritization of quality requirements (QR) in collaborative product development is studied. The requirements for a quality product are often obtained by questioning and interviewing targeted customers. However, the targeted customers often are not able to clearly articulate and be specific on what constitute a quality product. Even for those clearly specified requirements, they may not be able to determine the relative importance. Moreover, concerns of the developer’s organization and the society, such as the company goals and priorities as well as environmental regulations, may not get necessary attention by customers. Hence, efforts to prioritize QR’s across all stakeholders in developing a quality product are necessary. Prior research has focused on developing a process of prioritizing QR’s. Although our proposed urn-scheme method in prioritizing QR’s may be considered yet another voting mechanism, it differs in two major directions. Firstly, the proposed method explicitly incorporates social dynamic factors such as interpersonal trust and trustworthiness into the voting process. These latent factors are quantified and measured allowing us to visualize their effects on individual stakeholder’s prioritization list. Secondly, with the most trusted stakeholders’ prioritization lists amplified and the least trusted stakeholders’ opinions down weighed, the final combined prioritization list, weighing over all individual lists, is the result of the direct voting and social dynamics, all quantified, and thus, relative importance of quality requirements can be derived. The most important requirements are typically viewed by most stakeholders as important and particularly so by the most trusted stakeholders. A discussion on possible voting results is given. Extension of the proposed method to cover issues such as power influence and conflicts as well as degree of consensus is also provided.Copyright © 2005 by ASME

When design decisions are made by a group of diverse stakeholders, the decision making process is affected by both technical and social dynamic factors and the design results are consequently a product of the joint influences. Though it is important, the role of social dynamic factors in design process is currently not well understood. In this work, our study is focused on a prioritising problem concerning understanding customer needs at the early stage, in particular, identifying Quality Requirements and their relative importance. We introduced one among many social dynamic factors, i.e. trust and investigated its role in the early stage design decision making of product development. Derived from the definition and principle forms of general trust, the trust concept used in the prioritising problem for our study is specified. The existing measurement scales used in social science are modified for measuring the trust in terms of trustworthiness.