Showing papers by "University of Nebraska–Lincoln published in 2007"

Positive psychological capital: measurement and relationship with performance and satisfaction

Abstract: Two studies were conducted to analyze how hope, resilience, optimism, and efficacy individually and as a composite higher-order factor predicted work performance and satisfaction. Results from Study 1 provided psychometric support for a new survey measure designed to assess each of these 4 facets, as well as a composite factor. Study 2 results indicated a significant positive relationship regarding the composite of these 4 facets with performance and satisfaction. Results from Study 2 also indicated that the composite factor may be a better predictor of performance and satisfaction than the 4 individual facets. Limitations and practical implications conclude the article.

The Chlamydomonas Genome Reveals the Evolution of Key Animal and Plant Functions

Abstract: Chlamydomonas reinhardtii is a unicellular green alga whose lineage diverged from land plants over 1 billion years ago. It is a model system for studying chloroplast-based photosynthesis, as well as the structure, assembly, and function of eukaryotic flagella (cilia), which were inherited from the common ancestor of plants and animals, but lost in land plants. We sequenced the approximately 120-megabase nuclear genome of Chlamydomonas and performed comparative phylogenomic analyses, identifying genes encoding uncharacterized proteins that are likely associated with the function and biogenesis of chloroplasts or eukaryotic flagella. Analyses of the Chlamydomonas genome advance our understanding of the ancestral eukaryotic cell, reveal previously unknown genes associated with photosynthetic and flagellar functions, and establish links between ciliopathy and the composition and function of flagella.

Qualitative Research Designs: Selection and Implementation

Abstract: Counseling psychologists face many approaches from which to choose when they conduct a qualitative research study. This article focuses on the processes of selecting, contrasting, and implementing five different qualitative approaches. Based on an extended example related to test interpretation by counselors, clients, and communities, this article provides a detailed discussion about five qualitative approaches— narrative research; case study research; grounded theory; phenomenology; and participatory action research—as alternative qualitative procedures useful in understanding test interpretation. For each approach, the authors offer perspectives about historical origins, definition, variants, and the procedures of research.

Complexity Leadership Theory: Shifting leadership from the industrial age to the knowledge era !

Abstract: According to Hitt (1998), “we are on the precipice of an epoch,” in the midst of a new economic age, in which twenty-first century organizations are facing a complex competitive landscape driven largely by globalization and the technological revolution. This new age is about an economy where knowledge is a core commodity and the rapid production of knowledge and innovation is critical to organizational survival (Bettis and Hitt, 1995; Boisot, 1998). Consistent with these changes, much discussion is taking place in the management literature regarding challenges facing organizations in a transitioning world (Barkema et al., 2002; Bettis and Hitt, 1995; Child and McGrath, 2001).

CMS physics technical design report, volume II: Physics performance

Abstract: CMS is a general purpose experiment, designed to study the physics of pp collisions at 14 TeV at the Large Hadron Collider (LHC). It currently involves more than 2000 physicists from more than 150 institutes and 37 countries. The LHC will provide extraordinary opportunities for particle physics based on its unprecedented collision energy and luminosity when it begins operation in 2007. The principal aim of this report is to present the strategy of CMS to explore the rich physics programme offered by the LHC. This volume demonstrates the physics capability of the CMS experiment. The prime goals of CMS are to explore physics at the TeV scale and to study the mechanism of electroweak symmetry breaking--through the discovery of the Higgs particle or otherwise. To carry out this task, CMS must be prepared to search for new particles, such as the Higgs boson or supersymmetric partners of the Standard Model particles, from the start-up of the LHC since new physics at the TeV scale may manifest itself with modest data samples of the order of a few fb−1 or less. The analysis tools that have been developed are applied to study in great detail and with all the methodology of performing an analysis on CMS data specific benchmark processes upon which to gauge the performance of CMS. These processes cover several Higgs boson decay channels, the production and decay of new particles such as Z' and supersymmetric particles, Bs production and processes in heavy ion collisions. The simulation of these benchmark processes includes subtle effects such as possible detector miscalibration and misalignment. Besides these benchmark processes, the physics reach of CMS is studied for a large number of signatures arising in the Standard Model and also in theories beyond the Standard Model for integrated luminosities ranging from 1 fb−1 to 30 fb−1. The Standard Model processes include QCD, B-physics, diffraction, detailed studies of the top quark properties, and electroweak physics topics such as the W and Z0 boson properties. The production and decay of the Higgs particle is studied for many observable decays, and the precision with which the Higgs boson properties can be derived is determined. About ten different supersymmetry benchmark points are analysed using full simulation. The CMS discovery reach is evaluated in the SUSY parameter space covering a large variety of decay signatures. Furthermore, the discovery reach for a plethora of alternative models for new physics is explored, notably extra dimensions, new vector boson high mass states, little Higgs models, technicolour and others. Methods to discriminate between models have been investigated. This report is organized as follows. Chapter 1, the Introduction, describes the context of this document. Chapters 2-6 describe examples of full analyses, with photons, electrons, muons, jets, missing ET, B-mesons and τ's, and for quarkonia in heavy ion collisions. Chapters 7-15 describe the physics reach for Standard Model processes, Higgs discovery and searches for new physics beyond the Standard Model

Correlation of the highest-energy cosmic rays with nearby extragalactic objects.

Abstract: Using data collected at the Pierre Auger Observatory during the past 3.7 years, we demonstrate that there is a correlation between the arrival directions of cosmic rays with energy above {approx} 6 x 10{sup 19} eV and the positions of active galactic nuclei (AGN) lying within {approx} 75 Mpc. We reject the hypothesis of an isotropic distribution of these cosmic rays at over 99% confidence level from a prescribed a priori test. The correlation we observe is compatible with the hypothesis that the highest energy particles originate from nearby extragalactic sources whose flux has not been significantly reduced by interaction with the cosmic background radiation. AGN or objects having a similar spatial distribution are possible sources.

Promoting more integrative strategies for leadership theory-building.

Abstract: The agenda for theory and research in the field of leadership studies has evolved over the last 100 years from focuses on the internal dispositions associated with effective leaders to broader inquiries that include emphases on the cognitions, attributes, behaviors, and contexts in which leaders and followers are dynamically embedded and interact over time. Leadership theory and research has reached a point in its development at which it needs to move to the next level of integration--considering the dynamic interplay between leaders and followers, taking into account the prior, current, and emerging context--for continued progress to be made in advancing both the science and practice of leadership.

Modified dmo enzyme and methods of its use

Abstract: The invention provides a modified variant of dicamba monooxygenase (DMO). The invention relates to the unexpected finding that cells expressing this DMO exhibit high levels of tolerance to the herbicide dicamba. Compositions comprising DMO-encoding nucleic acids and methods of use are provided.

CRISPR recognition tool (CRT): a tool for automatic detection of clustered regularly interspaced palindromic repeats.

Abstract: Clustered Regularly Interspaced Palindromic Repeats (CRISPRs) are a novel type of direct repeat found in a wide range of bacteria and archaea. CRISPRs are beginning to attract attention because of their proposed mechanism; that is, defending their hosts against invading extrachromosomal elements such as viruses. Existing repeat detection tools do a poor job of identifying CRISPRs due to the presence of unique spacer sequences separating the repeats. In this study, a new tool, CRT, is introduced that rapidly and accurately identifies CRISPRs in large DNA strings, such as genomes and metagenomes. CRT was compared to CRISPR detection tools, Patscan and Pilercr. In terms of correctness, CRT was shown to be very reliable, demonstrating significant improvements over Patscan for measures precision, recall and quality. When compared to Pilercr, CRT showed improved performance for recall and quality. In terms of speed, CRT proved to be a huge improvement over Patscan. Both CRT and Pilercr were comparable in speed, however CRT was faster for genomes containing large numbers of repeats. In this paper a new tool was introduced for the automatic detection of CRISPR elements. This tool, CRT, showed some important improvements over current techniques for CRISPR identification. CRT's approach to detecting repetitive sequences is straightforward. It uses a simple sequential scan of a DNA sequence and detects repeats directly without any major conversion or preprocessing of the input. This leads to a program that is easy to describe and understand; yet it is very accurate, fast and memory efficient, being O(n) in space and O(nm/l) in time.

The cost of reproduction: the devil in the details

Abstract: The cost of reproduction is of fundamental importance in life-history evolution. However, our understanding of its mechanistic basis has been limited by a lack of detailed functional information at all biological levels. Here, we identify, evaluate and integrate recent studies in five areas examining the proximate mechanisms underlying the cost of reproduction. Rather than being alternate explanations, hormonal regulation and intermediary metabolism act in concert and have an overarching influence in shaping the cost of reproduction. Immune function is compromised by reproduction, as is resistance to environmental stress. These studies not only provide new information about mechanisms that comprise 'the cost', but also hint at an underlying evolutionarily conserved causal mechanism.

Acculturative stress, social support, and coping: relations to psychological adjustment among Mexican American college students.

Abstract: This study examined the relations between acculturative stress and psychological functioning, as well as the protective role of social support and coping style, in a sample of 148 Mexican American college students (67% female, 33% male; mean age = 2305 years, SD = 333) In bivariate analyses, acculturative stress was associated with higher levels of anxiety and depressive symptoms Moreover, active coping was associated with better adjustment (lower depression), whereas avoidant coping predicted poorer adjustment (higher levels of depression and anxiety) Tests of interaction effects indicated that parental support and active coping buffered the effects of high acculturative stress on anxiety symptoms and depressive symptoms In addition, peer support moderated the relation between acculturative stress and anxiety symptoms Implications for reducing the effects of acculturative stress among Mexican American college students are discussed

Understanding the complex impacts of drought: A key to enhancing drought mitigation and preparedness

Abstract: Recent droughts in the United States have highlighted the nation’s current and increasing vulnerability to this natural hazard. Drought-related impacts are also becoming more complex, as illustrated by the rapidly rising impacts in sectors such as recreation and tourism, energy, and transportation. Environmental and social consequences are also of increasing importance. Conflicts between water users and disputes between political entities on transboundary water issues are a reflection of the need for improved documentation of the consequences of extended periods of water shortage. Unfortunately, no national drought impact database exists and drought impact statistics are not routinely compiled at the state, regional, or national level. Without this information, it is an arduous task to convince policy and other decision makers of the need for additional investments in drought monitoring and prediction, mitigation, and preparedness. The National Drought Mitigation Center at the University of Nebraska-Lincoln is addressing this problem by creating a web-based Drought Impact Reporter (DIR) that has the following primary functions: (1) to create a database archive of drought impacts information; (2) to provide an interactive map delivery system that is efficient and user-oriented; (3) to build links with governmental agencies, non-governmental organizations, university research groups and extension programs, and others, including the public, in order to provide timely impact reports to ensure a comprehensive collection of drought impacts across all potential sectors and scales; and (4) to foster a continual process of user feedback, evaluation, assessment, and dissemination of drought impacts. The Drought Impact Reporter was launched in July 2005 and is available on the NDMC’s web site (http://drought.unl.edu).

A five‐year analysis of MODIS NDVI and NDWI for grassland drought assessment over the central Great Plains of the United States

Abstract: Received 18 December 2006; revised 16 February 2007; accepted 28 February 2007; published 27 March 2007. [1] A five-year (2001–2005) history of moderate resolution imaging spectroradiometer (MODIS) normalized difference vegetation index (NDVI) and normalized difference water index (NDWI) data was analyzed for grassland drought assessment within the central United States, specifically for the Flint Hills of Kansas and Oklahoma. Initial results show strong relationships among NDVI, NDWI, and drought conditions. During the summer over the Tallgrass Prairie National Preserve, the average NDVI and NDWI were consistently lower (NDVI 0.6 and NDWI>0.4). NDWI values exhibited a quicker response to drought conditions than NDVI. Analysis revealed that combining information from visible, near infrared, and short wave infrared channels improved sensitivity to drought severity. The proposed normalized difference drought index (NDDI) had a stronger response to summer drought conditions than a simple difference between NDVI and NDWI, and is therefore a more sensitive indicator of drought in grasslands than NDVI alone.Citation: Gu, Y., J. F. Brown, J. P. Verdin, and B. Wardlow (2007), A five-year analysis of MODIS NDVI and NDWI for grassland drought assessment over the central Great Plains of the United States, Geophys. Res. Lett., 34, L06407, doi:10.1029/ 2006GL029127.

The Treatment for Adolescents with Depression Study (TADS): Long-term effectiveness and safety outcomes

Abstract: CONTEXT: The Treatment for Adolescents With Depression Study evaluates the effectiveness of fluoxetine hydrochloride therapy, cognitive behavior therapy (CBT), and their combination in adolescents with major depressive disorder. OBJECTIVE: To report effectiveness outcomes across 36 weeks of randomized treatment. DESIGN AND SETTING: Randomized, controlled trial conducted in 13 academic and community sites in the United States. Cognitive behavior and combination therapies were not masked, whereas administration of placebo and fluoxetine was double-blind through 12 weeks, after which treatments were unblinded. Patients assigned to placebo were treated openly after week 12, and the placebo group is not included in these analyses by design. PARTICIPANTS: Three hundred twenty-seven patients aged 12 to 17 years with a primary DSM-IV diagnosis of major depressive disorder. INTERVENTIONS: All treatments were administered per protocol. MAIN OUTCOME MEASURES: The primary dependent measures rated blind to treatment status by an independent evaluator were the Children's Depression Rating Scale-Revised total score and the response rate, defined as a Clinical Global Impressions-Improvement score of much or very much improved. RESULTS: Intention-to-treat analyses on the Children's Depression Rating Scale-Revised identified a significant time x treatment interaction (P Language: en

Audit Quality and Properties of Analyst Earnings Forecasts

Abstract: Under the assumption that audit quality relates positively to unobservable financial reporting reliability, we investigate whether audit quality is associated with the predictability of accounting earnings by focusing on analyst earnings forecast properties. The evidence shows that analysts' earnings forecast accuracy is higher and the forecast dispersion is smaller for firms audited by a Big Five auditor. We further find that auditor industry specialization is associated with higher forecast accuracy and less forecast dispersion in the non-Big Five auditor sample but not in the Big Five auditor sample. Overall, our results suggest that high quality audit provided by Big Five auditors and industry specialist non-Big Five auditors is associated with better forecasting performance by analysts.

CO2-Forced Climate and Vegetation Instability During Late Paleozoic Deglaciation

Abstract: The late Paleozoic deglaciation is the vegetated Earth9s only recorded icehouse-to-greenhouse transition, yet the climate dynamics remain enigmatic. By using the stable isotopic compositions of soil-formed minerals, fossil-plant matter, and shallow-water brachiopods, we estimated atmospheric partial pressure of carbon dioxide (pCO2) and tropical marine surface temperatures during this climate transition. Comparison to southern Gondwanan glacial records documents covariance between inferred shifts in pCO2, temperature, and ice volume consistent with greenhouse gas forcing of climate. Major restructuring of paleotropical flora in western Euramerica occurred in step with climate and pCO2 shifts, illustrating the biotic impact associated with past CO2-forced turnover to a permanent ice-free world.

Approximating variance of demographic parameters using the delta method: a reference for avian biologists

Abstract: Avian biologists routinely estimate sampling variance for parameter estimates such as daily nest survival, fecundity, annual survival, and density However, many biologists are not certain of methods to derive sampling variance for parameters when survival rates change temporal scales Similar methods are needed to obtain sampling variance when biologists combine parameter estimates to calculate an indirect demographic parameter, such as population growth rate The delta method is a useful technique for approximating sampling variance when the desired demographic parameter is a function of at least one other demographic parameter However, the delta method is rarely taught in most graduate-level biology or ecology courses, and application of this method may be discouraged by seemingly daunting formulas in reference books Here, I provide five examples of sampling variance approximations for common situations encountered by avian ecologists, with step-by-step explanations of the equations involved

CMS physics technical design report: Addendum on high density QCD with heavy ions

Abstract: This report presents the capabilities of the CMS experiment to explore the rich heavy-ion physics programme offered by the CERN Large Hadron Collider (LHC). The collisions of lead nuclei at energies , will probe quark and gluon matter at unprecedented values of energy density. The prime goal of this research is to study the fundamental theory of the strong interaction ? Quantum Chromodynamics (QCD) ? in extreme conditions of temperature, density and parton momentum fraction (low-x).This report covers in detail the potential of CMS to carry out a series of representative Pb-Pb measurements. These include bulk observables, (charged hadron multiplicity, low pT inclusive hadron identified spectra and elliptic flow) which provide information on the collective properties of the system, as well as perturbative probes such as quarkonia, heavy-quarks, jets and high pT hadrons which yield tomographic information of the hottest and densest phases of the reaction.

A practical approach to phylogenomics: the phylogeny of ray-finned fish (Actinopterygii) as a case study.

Abstract: Molecular systematics occupies one of the central stages in biology in the genomic era, ushered in by unprecedented progress in DNA technology. The inference of organismal phylogeny is now based on many independent genetic loci, a widely accepted approach to assemble the tree of life. Surprisingly, this approach is hindered by lack of appropriate nuclear gene markers for many taxonomic groups especially at high taxonomic level, partially due to the lack of tools for efficiently developing new phylogenetic makers. We report here a genome-comparison strategy to identifying nuclear gene markers for phylogenetic inference and apply it to the ray-finned fishes – the largest vertebrate clade in need of phylogenetic resolution. A total of 154 candidate molecular markers – relatively well conserved, putatively single-copy gene fragments with long, uninterrupted exons – were obtained by comparing whole genome sequences of two model organisms, Danio rerio and Takifugu rubripes. Experimental tests of 15 of these (randomly picked) markers on 36 taxa (representing two-thirds of the ray-finned fish orders) demonstrate the feasibility of amplifying by PCR and directly sequencing most of these candidates from whole genomic DNA in a vast diversity of fish species. Preliminary phylogenetic analyses of sequence data obtained for 14 taxa and 10 markers (total of 7,872 bp for each species) are encouraging, suggesting that the markers obtained will make significant contributions to future fish phylogenetic studies. We present a practical approach that systematically compares whole genome sequences to identify single-copy nuclear gene markers for inferring phylogeny. Our method is an improvement over traditional approaches (e.g., manually picking genes for testing) because it uses genomic information and automates the process to identify large numbers of candidate makers. This approach is shown here to be successful for fishes, but also could be applied to other groups of organisms for which two or more complete genome sequences exist, which has important implications for assembling the tree of life.

A type III effector ADP-ribosylates RNA-binding proteins and quells plant immunity

Abstract: The bacterial plant pathogen Pseudomonas syringae injects effector proteins into host cells through a type III protein secretion system to cause disease. The enzymatic activities of most of P. syringae effectors and their targets remain obscure. Here we show that the type III effector HopU1 is a mono-ADP-ribosyltransferase (ADP-RT). HopU1 suppresses plant innate immunity in a manner dependent on its ADP-RT active site. The HopU1 substrates in Arabidopsis thaliana extracts were RNA-binding proteins that possess RNA-recognition motifs (RRMs). A. thaliana knockout lines defective in the glycine-rich RNA-binding protein GRP7 (also known as AtGRP7), a HopU1 substrate, were more susceptible than wild-type plants to P. syringae. The ADP-ribosylation of GRP7 by HopU1 required two arginines within the RRM, indicating that this modification may interfere with GRP7's ability to bind RNA. Our results suggest a pathogenic strategy where the ADP-ribosylation of RNA-binding proteins quells host immunity by affecting RNA metabolism and the plant defence transcriptome.

A soybean transcript map: gene distribution, haplotype and single-nucleotide polymorphism analysis.

Abstract: The first genetic transcript map of the soybean genome was created by mapping one SNP in each of 1141 genes in one or more of three recombinant inbred line mapping populations, thus providing a picture of the distribution of genic sequences across the mapped portion of the genome Single-nucleotide polymorphisms (SNPs) were discovered via the resequencing of sequence-tagged sites (STSs) developed from expressed sequence tag (EST) sequence From an initial set of 9459 polymerase chain reaction primer sets designed to a diverse set of genes, 4240 STSs were amplified and sequenced in each of six diverse soybean genotypes In the resulting 244 Mbp of aligned sequence, a total of 5551 SNPs were discovered, including 4712 single-base changes and 839 indels for an average nucleotide diversity of θ = 0000997 The analysis of the observed genetic distances between adjacent genes vs the theoretical distribution based upon the assumption of a random distribution of genes across the 20 soybean linkage groups clearly indicated that genes were clustered Of the 1141 genes, 291 mapped to 72 of the 112 gaps of 5–10 cM in the preexisting simple sequence repeat (SSR)-based map, while 111 genes mapped in 19 of the 26 gaps >10 cM The addition of 1141 sequence-based genic markers to the soybean genome map will provide an important resource to soybean geneticists for quantitative trait locus discovery and map-based cloning, as well as to soybean breeders who increasingly depend upon marker-assisted selection in cultivar improvement