Showing papers by "Oklahoma State University–Stillwater published in 2006"

Insights into social insects from the genome of the honeybee Apis mellifera

Abstract: Here we report the genome sequence of the honeybee Apis mellifera, a key model for social behaviour and essential to global ecology through pollination. Compared with other sequenced insect genomes, the A. mellifera genome has high A+T and CpG contents, lacks major transposon families, evolves more slowly, and is more similar to vertebrates for circadian rhythm, RNA interference and DNA methylation genes, among others. Furthermore, A. mellifera has fewer genes for innate immunity, detoxification enzymes, cuticle-forming proteins and gustatory receptors, more genes for odorant receptors, and novel genes for nectar and pollen utilization, consistent with its ecology and social organization. Compared to Drosophila, genes in early developmental pathways differ in Apis, whereas similarities exist for functions that differ markedly, such as sex determination, brain function and behaviour. Population genetics suggests a novel African origin for the species A. mellifera and insights into whether Africanized bees spread throughout the New World via hybridization or displacement.

Immune pathways and defence mechanisms in honey bees Apis mellifera

Abstract: Social insects are able to mount both group-level and individual defences against pathogens. Here we focus on individual defences, by presenting a genome-wide analysis of immunity in a social insect, the honey bee Apis mellifera. We present honey bee models for each of four signalling pathways associated with immunity, identifying plausible orthologues for nearly all predicted pathway members. When compared to the sequenced Drosophila and Anopheles genomes, honey bees possess roughly one-third as many genes in 17 gene families implicated in insect immunity. We suggest that an implied reduction in immune flexibility in bees reflects either the strength of social barriers to disease, or a tendency for bees to be attacked by a limited set of highly coevolved pathogens.

Identity, Intended Image, Construed Image, and Reputation: An Interdisciplinary Framework and Suggested Terminology

Abstract: Many scholars across various academic disciplines are investigating the following questions: What do individuals know or believe about an organization? How does a focal organization (and/or other interested entity) develop, use, and/or change this information? and How do individuals respond to what they know or believe about an organization? Cross-disciplinary research that centers on these questions is desirable and could be enhanced if researchers identify and develop consistent terminology for framing these questions. The authors work toward that end by identifying four central ‘viewpoints’ of an organization and proposing labels to represent each of these viewpoints:identity, intended image, construed image, andreputation.

Direct Ink Writing of Three‐Dimensional Ceramic Structures

Abstract: The ability to pattern ceramic materials in three dimensions (3D) is critical for structural, functional, and biomedical applications. One facile approach is direct ink writing (DIW), in which 3D structures are built layer-by-layer through the deposition of colloidal- or polymer-based inks. This approach allows one to design and rapidly fabricate ceramic materials in complex 3D shapes without the need for expensive tooling, dies, or lithographic masks. In this feature article, we present both droplet- and filament-based DIW techniques. We focus on the various ink designs and their corresponding rheological behavior, ink deposition mechanics, potential shapes and the toolpaths required, and representative examples of 3D ceramic structures assembled by each technique. The opportunities and challenges associated with DIW are also highlighted.

Should heterogeneity be the basis for conservation? Grassland bird response to fire and grazing.

Abstract: In tallgrass prairie, disturbances such as grazing and fire can generate patchiness across the landscape, contributing to a shifting mosaic that presumably enhances biodiversity. Grassland birds evolved within the context of this shifting mosaic, with some species restricted to one or two patch types created under spatially and temporally distinct disturbance regimes. Thus, management-driven reductions in heterogeneity may be partly responsible for declines in numbers of grassland birds. We experimentally altered spatial heterogeneity of vegetation structure within a tallgrass prairie by varying the spatial and temporal extent of fire and by allowing grazing animals to move freely among burned and unburned patches (patch treatment). We contrasted this disturbance regime with traditional agricultural management of the region that promotes homogeneity (traditional treatment). We monitored grassland bird abundance during the breeding seasons of 2001-2003 to determine the influence of altered spatial heterogeneity on the grassland bird community. Focal disturbances of patch burning and grazing that shifted through the landscape over several years resulted in a more heterogeneous pattern of vegetation than uniform application of fire and grazing. Greater spatial heterogeneity in vegetation provided greater variability in the grassland bird community. Some bird species occurred in greatest abundance within focally disturbed patches, while others occurred in relatively undisturbed patches in our patch treatment. Henslow's Sparrow, a declining species, occurred only within the patch treatment. Upland Sandpiper and some other species were more abundant on recently disturbed patches within the same treatment. The patch burn treatment created the entire gradient of vegetation structure required to maintain a suite of grassland bird species that differ in habitat preferences. Our study demonstrated that increasing spatial and temporal heterogeneity of disturbance in grasslands increases variability in vegetation structure that results in greater variability at higher trophic levels. Thus, management that creates a shifting mosaic using spatially and temporally discrete disturbances in grasslands can be a useful tool in conservation. In the case of North American tallgrass prairie, discrete fires that capitalize on preferential grazing behavior of large ungulates promote a shifting mosaic of habitat types that maintain biodiversity and agricultural productivity.

Does Hedging Affect Firm Value? Evidence from the US Airline Industry

Abstract: Does hedging add value to the firm, and if so, is the source of the added value consistent with hedging theory? We investigate jet fuel hedging behavior of firms in the US airline industry during 1992–2003 to examine whether such hedging is a source of value for these companies. We illustrate that the investment and financing climate in the airline industry conforms well to the theoretical framework of Froot, Scharfstein, and Stein (1993). In general, airline industry investment opportunities correlate positively with jet fuel costs, while higher fuel costs are consistent with lower cash flow. Given that jet fuel costs are hedgeable, airlines with a desire for expansion may find value in hedging future purchases of jet fuel. Our results show that jet fuel hedging is positively related to airline firm value. The coefficients on the hedging variables in our regression analysis suggest that the “hedging premium” is greater than the 5% documented in Allayannis and Weston (2001), and might be as large as 10%. We find that the positive relation between hedging and value increases in capital investment, and that most of the hedging premium is attributable to the interaction of hedging with investment. This result is consistent with the assertion that the principal benefit of jet fuel hedging by airlines comes from reduction of underinvestment costs.

A multilevel integration of personality, climate, self-regulation, and performance

Abstract: The purpose of this multilevel study was to test whether regulatory focus mechanisms (promotion focus and prevention focus; Higgins, 1997, American Psychologist, 52, 1280–1300; Higgins, 2000, American Psychologist, 55, 1217–1230) can help explain how group safety climate and individual differences in Conscientiousness relate to individual productivity and safety performance. Results, based on a sample of 254 employees from 50 work groups, showed that safety climate and conscientiousness predicted promotion and prevention regulatory focus, which in turn mediated the relationships of safety climate and Conscientiousness with supervisor ratings of productivity and safety performance. Implications for theory and research on climate, motivation, and performance and avenues for future research are discussed.

Predictors of Relationship Quality and Relationship Outcomes in Luxury Restaurants

Abstract: This study examines the relationships among elements of relationship management activities (predictors), relationship quality (a mediating construct), and relationship outcomes (commitment, loyalty, and word of mouth). Despite much research focusing on relationship quality, some central questions concerning the relationship among the three constructs have not been fully explored. A conceptual model was developed and tested to examine the mediating effect of relationship quality on the relationship between the seven relationship management activities and the three relationship outcomes. Structural equation analyses on the data collected from a survey of 887 dinner patrons at 21 luxury restaurants show that relationship quality is the primary mediating construct between relationship management activities and relationship outcomes. The effective use of a relationship management strategy may increase customer commitment, spread positive word of mouth, and generate loyalty. The findings of this study provide r...

In-Season Prediction of Corn Grain Yield Potential Using Normalized Difference Vegetation Index

Abstract: Drastic increases in the cost of N fertilizer and increased public scrutiny have encouraged development and implementation of improved N management practices. This study evaluated the relationship between corn (Zea mays L.) grain yield and early season normalized difference vegetation index (NDVI) sensor readings using the GreenSeeker sensor. The relationships between grain yield and several predictor variables were determined using linear and nonlinear regression analysis. Categorizing NDVI measurement by leaf stage indicated that growth stagewas criticalfor predictinggrain yield potential. Poor exponential relationships existed between NDVI from early sensor measurements (V6–V7 leaf stage) and grain yield. By the V8 stage, a strong relationship (R 2 5 0.77) was achieved between NDVI and grain yield. Later sensor measurements (V9 and later) failed to distinguish variation in green biomass as a result of canopy closure. Normalizing the NDVI with GDD (growing degree days) did not significantly improve yield potential prediction (R 2 5 0.73), but broadened the yield potential prediction equation to include temperature and allowed for adaptation into various climates. Sensor measurements at the range of 800 to 1000 GDD resulted in a significant exponential relationship between grain yield and NDVI (R 2 5 0.76) similar to the V8 leaf stage categorization. Categorizing NDVI by GDD (800–1000 GDD) extended the sensing time by two additional leaf stages (V7–V9) to allow a practical window of opportunity for sidedress N applications. This study showed that yield potential in corn could be accurately predicted in season with NDVI measured with the GreenSeeker sensor.

Premarital education, marital quality, and marital stability: findings from a large, random household survey.

Abstract: One of the limitations of experimental studies on the effectiveness of premarital education is the reliance on samples of mostly White, middle-class couples. In contrast, although survey methods allow only weak inferences about causal relations, representative surveys can yield important information about use and estimated effects across a diverse population. Using a large random survey of 4 middle American states, the authors found that participation in premarital education was associated with higher levels of satisfaction and commitment in marriage and lower levels of conflict-and also reduced odds of divorce. These estimated effects were robust across race, income (including among the poor), and education levels, which suggests that participation in premarital education is generally beneficial for a wide range of couples.

Predicting box-office success of motion pictures with neural networks

Abstract: Predicting box-office receipts of a particular motion picture has intrigued many scholars and industry leaders as a difficult and challenging problem. In this study, the use of neural networks in predicting the financial performance of a movie at the box-office before its theatrical release is explored. In our model, the forecasting problem is converted into a classification problem-rather than forecasting the point estimate of box-office receipts, a movie based on its box-office receipts in one of nine categories is classified, ranging from a 'flop' to a 'blockbuster.' Because our model is designed to predict the expected revenue range of a movie before its theatrical release, it can be used as a powerful decision aid by studios, distributors, and exhibitors. Our prediction results is presented using two performance measures: average percent success rate of classifying a movie's success exactly, or within one class of its actual performance. Comparison of our neural network to models proposed in the recent literature as well as other statistical techniques using a 10-fold cross validation methodology shows that the neural networks do a much better job of predicting in this setting.

Fertilization and Nitrogen Balance in a Wheat–Maize Rotation System in North China

Abstract: Over N fertilization is a common problem for the winter wheat (Triticum aestivum L.)-summer maize (Zea mays L.) rotation system in the North China Plain. A field experiment which included control (no N), conventional N (Con. N) fertilization, and optimized N (N min ) fertilization treatments, was conducted from 1999 to 2003 near Beijing, China. Soil nitrate (NO 3 ) dynamics were measured and N balance was calculated for the period of the eight successive cropping seasons. Soil NO 3 -N in the 0- to 90-cm profile for the Con. N treatment ranged from 157 to 700 kg ha -1 during the eight successive cropping seasons, much greater than those in the no N and optimized N treatments. Large amounts of soil NO 3 -N were detected in the 90- to 200-cm layer under the conventional N fertilization treatment, especially in the summer maize season. For the N min treatment, the total amount of N applied was 511 kg N ha -1 in the eight successive crops as compared with 2400 kg N ha -1 of the Con. N treatment. Grain yields were not different between the fertilized treatments except for maize in 2003. Soil NO 3 -N in the root zone under conditions of optimized N fertilization was maintained at a relatively low level as compared with the Con. N treatment, therefore dramatically decreasing NO 3 -N movement to deeper soil profile. This study indicates that soil NO 3 movement out of the effective crop root zone is an important pathway of N losses in this winter wheat-summer maize rotation system in the North China Plain and the optimized N fertilization by an improved N min method shows high potential of reducing N-leaching losses.

Faster lizards sire more offspring: sexual selection on whole-animal performance

Abstract: Sexual selection operates by acting on variation in mating success. However, since selection acts on whole-organism manifestations (i.e., performance) of underlying morphological traits, tests for phenotypic effects of sexual selection should consider whole-animal performance as a substrate for sexual selection. Previous studies have revealed positive relationships between performance and survival, that is, natural selection, but none have explicitly tested whether performance may influence reproductive success (through more matings), that is, sexual selection. Performance predicts dominance in some species, implying the effects of sexual selection, but how it does so has not been established, nor is it certain whether performance might be a by-product of selection for something else, for example, elevated circulating testosterone levels. We investigated the potential for sexual selection on sprint speed performance in collared lizards (Crotaphytus collaris), considering the potential mediating effects of circulating hormone levels. Among territorial, adult male collared lizards, only sprint speed significantly predicted territory area and number of offspring sired as determined by genetic paternity analysis. Body size, head size, and hind limb length had no effect. Neither plasma testosterone levels nor corticosterone levels correlated with sprint speed, territory area, or number of offspring sired. Thus, our results provide a direct link between whole-animal performance and reproductive success, suggesting that intrasexual selection can act directly on sprint speed performance and drive the evolution of underlying morphological traits.

Chemical, Physical, and Mechanical Characterization of Isocyanate Cross-linked Amine-Modified Silica Aerogels

Abstract: We describe a new mechanically strong lightweight porous composite material obtained by encapsulating the skeletal framework of amine-modified silica aerogels with polyurea. The conformal polymer coating preserves the mesoporous structure of the underlying silica framework and the thermal conductivity remains low at 0.041 plus or minus 0.001 W m(sup -1 K(sup -1). The potential of the new cross-linked silica aerogels for load-carrying applications was determined through characterization of their mechanical behavior under compression, three-point bending, and dynamic mechanical analysis (DMA). A primary glass transition temperature of 130 C was identified through DMA. At room temperature, results indicate a hyperfoam behavior where in compression cross-linked aerogels are linearly elastic under small strains (less than 4%) and then exhibit yield behavior (until 40% strain), followed by densification and inelastic hardening. At room temperature the compressive Young's modulus and the Poisson's ratio were determined to be 129 plus or minus 8 MPa and 0.18, respectively, while the strain at ultimate failure is 77% and the average specific compressive stress at ultimate failure is 3.89 x 10(exp 5) N m kg(sup -1). The specific flexural strength is 2.16 x 10(exp 4) N m kg(sup -1). Effects on the compressive behavior of strain rate and low temperature were also evaluated.

Do CEO Stock Options Prevent or Promote Fraudulent Financial Reporting

Abstract: We contrast the conventional view that CEO stock options aid corporate governance by reducing moral hazard with the proposal that CEO stock options may subvert sound corporate governance. Views wer...

Electronic Customer Relationship Management

Abstract: Electronic customer relationship management (eCRM) has become the latest paradigm in the world of customer relationship management. Recent business surveys suggest that up to 50 per cent of such implementations do not yield measurable returns on investment. A secondary analysis of 13 case studies suggests that many of these limited success implementations can be attributed to usability and resistance factors. The objective of this paper is to review the general usability and resistance principles in order to build an integrative framework for analyzing eCRM case studies. The conclusions suggest that if organizations want to get the most from their eCRM implementations they need to revisit the general principles of usability and resistance and apply them thoroughly and consistently.

A Self Adaptive Penalty Function Based Algorithm for Constrained Optimization

Abstract: This paper proposes a self adaptive penalty function for solving constrained optimization problems using genetic algorithms. In the proposed method, a new fitness value, called distance value, in the normalized fitness-constraint violation space, and two penalty values are applied to infeasible individuals so that the algorithm would be able to identify the best infeasible individuals in the current population. The method aims to encourage infeasible individuals with low objective function value and low constraint violation. The number of feasible individuals in the population is used to guide the search process either toward finding more feasible solutions or toward finding the optimum solution. The proposed method is simple to implement and does not need parameter tuning. The performance of the algorithm is tested on 13 benchmark functions in the literature. The results show that the approach is able to find very good solutions comparable to other state-of-the-art designs. Furthermore, it is able to find feasible solutions in every run for all of the benchmark functions.

Spectral Reflectance to Estimate Genetic Variation for In-Season Biomass, Leaf Chlorophyll, and Canopy Temperature in Wheat

Abstract: Spectral indices as a selection tool in plant breeding could improve genetic gains for different important traits. The objectives of this study were to assess the potential of using spectral reflectance indices (SRI) to estimate genetic variation for in-season biomass production, leaf chlorophyll, and canopy temperature (CT) in wheat (Triticum aestivum L.) under irrigated conditions. Three field experiments, GHIST (15 CIMMYT globally adapted historic genotypes), RILs1 (25 recombinant inbred lines [RILs]), and RILs2 (36 RILs) were conducted under irrigated conditions at the CIMMYT research station in northwest Mexico in three different years. Five SRI were evaluated to differentiate genotypes for biomass production. In general, genotypic variation for all the indices was significant. Near infrared radiation (NIR)–basedindicesgavethehighestlevelsofassociationwithbiomass production and the higher associations were observed at heading and grainfilling, rather than at booting. Overall, NIR-based indices were more consistent and differentiated biomass more effectively compared to the other indices. Indices based on ratio of reflection spectra cor

Quantitative trait loci for yield and related traits in the wheat population Ning7840 x Clark.

Abstract: Grain yield and associated agronomic traits are important factors in wheat (Triticum aestivum L.) improvement. Knowledge regarding the number, genomic location, and effect of quantitative trait loci (QTL) would facilitate marker-assisted selection and the development of cultivars with desirable characteristics. Our objectives were to identify QTLs directly and indirectly affecting grain yield expression. A population of 132 F12 recombinant inbred lines (RILs) was derived by single-seed descent from a cross between the Chinese facultative wheat Ning7840 and the US soft red winter wheat Clark. Phenotypic data were collected for 15 yield and other agronomic traits in the RILs and parental lines from three locations in Oklahoma from 2001 to 2003. Twenty-nine linkage groups, consisting of 363 AFLP and 47 SSR markers, were identified. Using composite interval mapping (CIM) analysis, 10, 16, 30, and 14 QTLs were detected for yield, yield components, plant adaptation (shattering and lodging resistance, heading date, and plant height), and spike morphology traits, respectively. The QTL effects ranged from 7 to 23%. Marker alleles from Clark were associated with a positive effect for the majority of QTLs for yield and yield components, but gene dispersion was the rule rather than the exception for this RIL population. Often, QTLs were detected in proximal positions for different traits. Consistent, co-localized QTLs were identified in linkage groups 1AL, 1B, 4B, 5A, 6A, and 7A, and less consistent but unique QTLs were identified on 2BL, 2BS, 2DL, and 6B. Results of this study provide a benchmark for future efforts on QTL identification for yield traits.

An Entrepreneur's Guide to the Venture Capital Galaxy

Abstract: Executive Overview This article provides a foundation for an understanding of the dynamics of venture capital from the entrepreneur's point of view. An important aspect of understanding venture capital involves the different sources of risk capital for the entrepreneur, i.e., (classic) venture capitalists (VCs), business angels, and corporate venture capitalists. Furthermore, whatever source of risk capital entrepreneurs choose, they have to take into account the different phases of the investment cycle, i.e., the pre-investment, post-investment, and exit phases. We discuss some of the key issues of which entrepreneurs need to be aware when dealing with venture capitalists during each of these three investment phases. Furthermore, we provide hands-on advice to help entrepreneurs maximize the value of their relationship with VCs throughout the investment cycle, and we point to trouble spots which can endanger value creation. For instance, in the pre-investment phase, the challenges of finding an (adequate)...

Strategies for development of vaccines for control of ixodid tick species.

Abstract: SUMMARY Ticks are distributed worldwide and impact human and animal health, as well as food animal production. Control of ticks has been primarily by application of acaricides, which has resulted in selection of resistant ticks and environmental pollution. Vaccines have been shown to be a feasible tick control method that offers a cost-effective, environmentally friendly alternative to chemical control. However, identification of tick-protective antigens remains the limiting step in vaccine development. Tick antigens exposed naturally to the host during tick feeding and those concealed have both shown promise as candidate vaccine antigens. Development of vaccines against multiple tick species may be possible using highly conserved tick-protective antigens or by antigens showing immune cross-reaction to different tick species. Vaccines made from a combination of key protective antigens may greatly enhance vaccine efficacy. Preliminary studies have suggested the possibility of vaccine strategies directed toward both tick control and the blocking of pathogen transmission. Characterization of the tick genomes will have a great impact on the discovery of new protective antigens. The future of research directed toward tick vaccine development is exciting because of new and emerging technologies for gene discovery, and vaccine formulation and delivery.

Neighborhood Disadvantage, Parent–Child Conflict, Neighborhood Peer Relationships, and Early Antisocial Behavior Problem Trajectories

Abstract: This study examined relations among neighborhood disadvantage, parent–child conflict, deviant peer involvement in the neighborhood, and early-starting antisocial trajectories Antisocial group patterns were identified in 218 low-income boys followed from ages 5 to 11, and neighborhood and family variables were evaluated as predictors in early and middle childhood Four trajectory groups emerged: one increasing pattern that corresponded with developmental theories of early-starting antisocial behavior; one with initially high and decreasing problems over time; and two low antisocial groups Parent–child conflict and neighborhood disadvantage were significantly associated with trajectory patterns, with youth in the 2 higher antisocial behavior groups characterized by more neighborhood problems and parent–child conflict than other groups The results suggest that in early childhood, neighborhood disadvantage and family conflict place children at risk for early-starting trajectories, and that involvement with deviant peers in the neighborhood takes on an increasingly important role in patterns of antisocial behavior over middle childhood

Positive and negative adjustment and social support of sexual assault survivors.

Abstract: The roles of positive (i.e., growth) and negative (i.e., posttraumatic stress symptoms and general symptomatology) adjustment following adult sexual assault experience(s) were examined using a standardized definition of abuse. These reactions were explored in association with positive and negative support from formal and informal providers. Finally, using standardized measures, the collective impact of positive and negative support, formal and informal support were investigated in predicting positive and negative psychological adjustment. Both forms of informal support were found to be associated with positive outcomes. Only negative informal support was associated with posttraumatic stress symptoms. First responders should consider whether support resources are appropriate to victims' needs.

Lower Bounds for an Integral Involving Fractional Laplacians and the Generalized Navier-Stokes Equations in Besov Spaces

Abstract: When estimating solutions of dissipative partial differential equations in L p -related spaces, we often need lower bounds for an integral involving the dissipative term. If the dissipative term is given by the usual Laplacian −Δ, lower bounds can be derived through integration by parts and embedding inequalities. However, when the Laplacian is replaced by the fractional Laplacian (−Δ) α , the approach of integration by parts no longer applies. In this paper, we obtain lower bounds for the integral involving (−Δ) α by combining pointwise inequalities for (−Δ) α with Bernstein's inequalities for fractional derivatives. As an application of these lower bounds, we establish the existence and uniqueness of solutions to the generalized Navier-Stokes equations in Besov spaces. The generalized Navier-Stokes equations are the equations resulting from replacing −Δ in the Navier-Stokes equations by (−Δ) α .