Showing papers by "Georgia State University published in 2011"

Nanoplasmonics: past, present, and glimpse into future

Abstract: A review of nanoplasmonics is given. This includes fundamentals, nanolocalization of optical energy and hot spots, ultrafast nanoplasmonics and control of the spatiotemporal nanolocalization of optical fields, and quantum nanoplasmonics (spaser and gain-assisted plasmonics). This article reviews both fundamental theoretical ideas in nanoplasmonics and selected experimental developments. It is designed both for specialists in the field and general physics readership.

Is Market Orientation a Source of Sustainable Competitive Advantage or Simply the Cost of Competing

Abstract: The authors use panel data constructed from the responses of repeatedly surveyed top managers at 261 companies regarding their firm’s market orientation, along with objective performance measures, to investigate the influence of market orientation on performance for a nine-year period from 1997 to 2005. The authors measure market orientation in 1997, 2001, and 2005 and estimate it in the interval between these measurement periods. The analyses indicate that market orientation has a positive effect on business performance in both the short and the long run. However, the sustained advantage in business performance from having a market orientation is greater for the firms that are early to develop a market orientation. These firms also gain more in sales and profit than firms that are late in developing a market orientation. Firms that adopt a market orientation may also realize additional benefit in the form of a lift in sales and profit due to a carryover effect. Market orientation should have a more pronounced effect on a firm’s profit than sales because a market orientation focuses efforts on customer retention rather than on acquisition. Environmental turbulence and competitive intensity moderate the main effect of market orientation on business performance, but the moderating effects are greater in the 1990s than in the 2000s.

A fluorescent probe for fast and quantitative detection of hydrogen sulfide in blood

Abstract: Hydrogen sulfide (H2S), well known for its unpleasant rotten egg smell, was traditionally considered as a toxic gas. However, recent studies have demonstrated that hydrogen sulfide is an endogenously produced gaseous signaling compound (gasotransmitter) with importance on par with that of the other two known endogenous gasotransmitters, nitric oxide (NO)[1] and carbon monoxide (CO).[2] H2S has been recognized for mediating a wide range of physiological effects. Studies have shown that H2S can have an effect on the cardiovascular system[3] by acting as a K-ATP channel opener.[4] Several studies have shown the protective roles of H2S, in situations such as myocardial ischemia, most likely through a combination of antioxidant and anti-apoptotic signaling.[5] Further studies also showed that H2S may be a therapeutic benefit for the treatment of ischemia-induced heart failure.[6-7] It is also a modulator in the central nervous system,[8-10] respiratory system, gastrointestinal system, and endocrine system.[11] It seems that hydrogen sulfide exhibits almost all the beneficial effects of NO without generating the toxic reactive oxygen species (ROS). In contrast, it also acts as an anti-oxidant or scavenger of ROS. Furthermore, research has indicated that hydrogen sulfide level is related to diseases such as Down syndrome[12] and Alzheimer’s disease.[13] Therefore, recent years have seen a steady increase in the interest in understanding hydrogen sulfide ’s physiological and pathological functions.[11, 14-15] One significant limiting factor in studying hydrogen sulfide is the lack of sensors and agents that allow for its rapid and accurate detection. There have been literature methods using colorimetric,[16-18] electrochemical analysis[19-21] and gas chromatography.[22-23] However, hydrogen sulfide catabolism is known to be fast, which could result in continuous fluctuation in its concentration, leading to difficulties in accurate analysis of this important molecule. Current methods do not allow for fast, accurate, and real-time determinations. Literature reported endogenous sulfide concentrations vary substantially among publications with most publications suggesting that sulfide concentration in blood is in the 10-100 μM range.[24-29] There are other studies suggesting sulfide concentration being much lower than this.[30-31] Therefore, there is an urgent need for the development of new methods for the efficient detection of sulfide in biological systems.

Sequential analysis and observational methods for the behavioral sciences

Abstract: 1. Introduction to observational methods 2. Coding schemes and observational measurement 3. Recording observational data 4. Representing observational data 5. Observer agreement and Cohen's kappa 6. Kappas for point-by-point agreement 7. The intraclass correlation coefficient (ICC) for summary measures 8. Summary statistics for individual codes 9. Cell and summary statistics for contingency tables 10. Preparing for sequential and other analyses 11. Time-window and log-linear sequential analysis 12. Recurrence analysis and permutation tests.

Drugs that target dynamic microtubules: a new molecular perspective.

Abstract: Microtubules have long been considered an ideal target for anticancer drugs because of the essential role they play in mitosis, forming the dynamic spindle apparatus. As such, there is a wide variety of compounds currently in clinical use and in development that act as antimitotic agents by altering microtubule dynamics. Although these diverse molecules are known to affect microtubule dynamics upon binding to one of the three established drug domains (taxane, vinca alkaloid, or colchicine site), the exact mechanism by which each drug works is still an area of intense speculation and research. In this study, we review the effects of microtubule-binding chemotherapeutic agents from a new perspective, considering how their mode of binding induces conformational changes and alters biological function relative to the molecular vectors of microtubule assembly or disassembly. These “biological vectors” can thus be used as a spatiotemporal context to describe molecular mechanisms by which microtubule-targeting drugs work.

Predictors of Abusive Supervision: Supervisor Perceptions of Deep-Level Dissimilarity, Relationship Conflict, and Subordinate Performance

Abstract: The moral exclusion literature identifies three previously unexamined predictors of abusive supervision: supervisor perceptions of deep-level dissimilarity, relationship conflict, and subordinate performance. Invoking theory and research on workplace diversity, relationship conflict, and victim precipitation, we model the three predictors as associated with abusive supervision. Path-analytic tests using data collected from supervisor-subordinate dyads at two time points suggest that supervisor perceptions of relationship conflict and subordinate performance mediate the relationship between perceived deep-level dissimilarity and abusive supervision and that relationship conflict mediates that between perceived deep-level dissimilarity and abusive supervision when supervisors perceive subordinates as having low performance. Estimates suggest that more than 13 percent of working people in the United States become targets of abusive supervision, or nonphysical hostility perpetrated by employees’ immediate superiors (Schat, Frone, & Kelloway, 2006). Examples of behaviors that fall within the abusive supervision content domain include undermining, public denigration, and explosive outbursts (Tepper, 2007). Sustained exposure to abusive supervision is associated with serious negative outcomes for victims and employers, including psychological distress (Tepper, 2000), problem drinking (Bamberger & Bacharach, 2006), and aggression directed against a

The Cognitive Perspective in Entrepreneurship: An Agenda for Future Research

Abstract: Despite its many achievements, scholarship at the intersection of entrepreneurship and cognition has focused primarily on the consequences of what happens when an entrepreneur benefits from various cognitive characteristics, resources, or other dispositions. As such, cognitive research in entrepreneurship continues to suffer from narrow theoretical articulations and weak conceptual foundations that lessen its contribution to the managerial sciences. To address these issues, we draw from extant work on the nature and practice of cognitive research to develop a systematic approach to study entrepreneurship cognition. To further articulate this agenda, we assess the state of the field by content-analysing entrepreneurship cognition articles published between 1976 and 2008. We find that, although it has investigated many relevant variables, research on entrepreneurship cognition has failed to fully articulate key conceptual features of the cognitive perspective. Building on these observations, we propose concrete strategies and research questions to augment the contribution of entrepreneurship cognition research, and advance this research beyond its current focus on ‘cognitive consequences’. In particular, we illustrate the scholarly potential of disentangling the various antecedents of entrepreneurship cognition, of studying the process interactions between cognitive resources and mental representations, and of exploring the operation of entrepreneurship cognition across levels of analysis.

A study of the routing and spectrum allocation in spectrum-sliced Elastic Optical Path networks

Abstract: In OFDM-based optical networks, multiple subcarriers can be allocated to accommodate various size of traffic demands. By using the multi-carrier modulation technique, subcarriers for the same node-pair can be overlapping in the spectrum domain. Compared to the traditional wavelength routed networks (WRNs), the OFDM-based Spectrum-sliced Elastic Optical Path (SLICE) network has higher spectrum efficiency due to its finer granularity and frequency-resource saving. In this work, for the first time, we comprehensively study the routing and spectrum allocation (RSA) problem in the SLICE network. After proving the NP-hardness of the static RSA problem, we formulate the RSA problem using the Integer Linear Programming (ILP) formulations to optimally minimize the maximum number of sub-carriers required on any fiber of a SLICE network. We then analyze the lower/upper bounds for the sub-carrier number in a network with general or specific topology. We also propose two efficient algorithms, namely, balanced load spectrum allocation (BLSA) algorithm and shortest path with maximum spectrum reuse (SPSR) algorithm to minimize the required sub-carrier number in a SLICE network. The results show that the proposed algorithms can match the analysis and approximate the optimal solutions using the ILP model.

Using Non-Pecuniary Strategies to Influence Behavior: Evidence from a Large Scale Field Experiment

Abstract: Policymakers are increasingly using norm-based messages to influence individual decision-making. We partner with a metropolitan water utility to implement a natural field experiment examining the effect of such messages on residential water demand. The data, drawn from more than 100,000 households, indicate that social comparison messages had a greater influence on behavior than simple pro-social messages or technical information alone. Moreover, our data suggest social comparison messages are most effective among households identified as the least price sensitive: high-users. Yet the effectiveness of such messages wanes over time. Our results thus highlight important complementarities between pecuniary and non-pecuniary strategies.

Challenges and business models for mobile location-based services and advertising

Abstract: Mobile advertising will become more pervasive and profitable, but not before addressing key technical and business challenges.

Synthesis and In Vivo Fate of Zwitterionic Near-Infrared Fluorophores

Abstract: A longstanding problem in the field of image-guided surgery is the development of ideal near-infrared (NIR) fluorophores. The heptamethine NIR fluorophore indocyanine green (ICG) has been used extensively for image-guided surgery because of clinical availability and safety.[1-3] However, ICG is far from ideal because it exhibits high uptake in the liver, contaminates the gastrointestinal (GI) tract, provides moderate optical properties,[4] is unstable in aqueous media,[3,5] and is unable to conjugate covalently to targeting ligands.[2] Although several classes of novel molecules have been described,[6-13] none to date exhibit simultaneous low background binding, bifunctionality, excellent optical properties, low protein binding, and high serum stability. Although it is intuitive that physicochemical properties, i.e., positive/negative charge density, hydrophilicity/lipophilicity, and charge distribution, will impact in vivo performance, chemical structures that exhibit ideal characteristics have not yet been defined.

Tournament Incentives, Firm Risk, and Corporate Policies

Abstract: This paper tests the proposition that higher tournament incentives will result in greater risk taking by senior managers in order to increase their chance of promotion to the rank of CEO. Measuring tournament incentives as the pay gap between the CEO and the next layer of senior managers, we find a significantly positive relation between firm risk and tournament incentives. Further, we find that greater tournament incentives lead to higher R&D intensity, firm focus, and leverage but lower capital expenditures intensity. Our results support the hypothesis that option-like features of intra-organizational CEO promotion tournaments provide incentives to senior executives to increase firm risk by following riskier policies. Finally, the compensation levels and structures of executives of financial institutions have received a great deal of scrutiny after the financial crisis. In a separate examination of financial firms, we again find a significantly positive relation between firm risk and tournament incentives.

Conditions associated with protected area success in conservation and poverty reduction

Abstract: Protected areas are the dominant approach to protecting biodiversity and the supply of ecosystem services. Because these protected areas are often placed in regions with widespread poverty and because they can limit agricultural development and exploitation of natural resources, concerns have been raised about their potential to create or reinforce poverty traps. Previous studies suggest that the protected area systems in Costa Rica and Thailand, on average, reduced deforestation and alleviated poverty. We examine these results in more detail by characterizing the heterogeneity of responses to protection conditional on observable characteristics. We find no evidence that protected areas trap historically poorer areas in poverty. In fact, we find that poorer areas at baseline seem to have the greatest levels of poverty reduction as a result of protection. However, we do find that the spatial characteristics associated with the most poverty alleviation are not necessarily the characteristics associated with the most avoided deforestation. We show how an understanding of these spatially heterogeneous responses to protection can be used to generate suitability maps that identify locations in which both environmental and poverty alleviation goals are most likely to be achieved.

Strength in the face of adversity: Resilience strategies of transgender individuals.

Abstract: This phenomenological inquiry explored the lived experiences of resilience of 21 transgender individuals. Through individual semistructured interviews (3 interviews each with 5 participants) and 1 focus group interview (16 participants), the authors identified 5 common resiliency themes (evolving a self-generated definition of self, embracing self-worth, awareness of oppression, connection with a supportive community, and cultivating hope for the future) and 2 variant themes (social activism and being a positive role model for others). Future practice and research directions are discussed.

Heavy-quark production in p + p and energy loss and flow of heavy quarks in Au + Au collisions at √sNN=200 GeV

Abstract: Transverse momentum spectra of electrons (p(T)(e)) from semileptonic weak decays of heavy-flavor mesons in the range of 0.3 < p(T)(e) < 9.0 GeV/c have been measured at midrapidity (|y| < 0.35) by the PHENIX experiment at the Relativistic Heavy Ion Collider in p + p and Au + Au collisions at root s(NN) = 200 GeV. In addition, the azimuthal anisotropy parameter v(2) has been measured for 0.3 < p(T)(e) < 5.0 GeV/c in Au + Au collisions. The substantial modification in the p(T)(e) spectra in Au + Au compared with p + p collisions as well as the nonzero v(2) indicate substantial interactions and flow of heavy quarks in traversing the produced medium. Comparisons of these observables with detailed theoretical calculations can be used to identify the nature of these interactions and to quantify their extent.

Measurement of neutral mesons in p+p collisions at √s=200GeV and scaling properties of hadron production

Abstract: The PHENIX experiment at the Relativistic Heavy Ion Collider has measured the invariant differential cross section for production of K-S(0), omega, eta', and phi mesons in p + p collisions at root s 200 GeV. Measurements of omega and phi production in different decay channels give consistent results. New results for the omega are in agreement with previously published data and extend the measured p(T) coverage. The spectral shapes of all hadron transverse momentum distributions measured by PHENIX are well described by a Tsallis distribution functional form with only two parameters, n and T, determining the high-p(T) and characterizing the low-p(T) regions of the spectra, respectively. The values of these parameters are very similar for all analyzed meson spectra, but with a lower parameter T extracted for protons. The integrated invariant cross sections calculated from the fitted distributions are found to be consistent with existing measurements and with statistical model predictions.

Measurements of higher order flow harmonics in Au+Au collisions at √sNN=200GeV

Abstract: Flow coefficients nu(n) for n = 2, 3, 4, characterizing the anisotropic collective flow in Au + Au collisions at root s(NN) = 200 GeV, are measured relative to event planes Psi(n), determined at large rapidity We report nu(n) as a function of transverse momentum and collision centrality, and study the correlations among the event planes of different order n The nu(n) are well described by hydrodynamic models which employ a Glauber Monte Carlo initial state geometry with fluctuations, providing additional constraining power on the interplay between initial conditions and the effects of viscosity as the system evolves This new constraint can serve to improve the precision of the extracted shear viscosity to entropy density ratio eta/s

Identified charged hadron production in p + p collisions at √ s = 200 and 62.4 GeV

Abstract: Transverse momentum distributions and yields for pi(+/-), K-+/-, p, and (p) over bar in p + p collisions at root s = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC). These data provide important baseline spectra for comparisons with identified particle spectra in heavy ion collisions at RHIC. We present the inverse slope parameter T-inv, mean transverse momentum , and yield per unit rapidity dN/dy at each energy, and compare them to other measurements at different root s in p + p and p + (p) over bar collisions. We also present the scaling properties such as m(T) scaling and x(T) scaling on the p(T) spectra between different energies. To discuss the mechanism of the particle production in p + p collisions, the measured spectra are compared to next-to-leading-order or next-to-leading-logarithmic perturbative quantum chromodynamics calculations.

Framing, Motivated Reasoning, and Opinions About Emergent Technologies

Abstract: How do individuals form opinions about new technologies? What role does factual information play? We address these questions by incorporating 2 dynamics, typically ignored in extant work: information competition and over-time processes. We present results from experiments on 2 technologies: carbon-nanotubes and genetically modified foods. We find that factual information is of limited utility—it does not have a greater impact than other background factors (e.g., values), it adds little power to newly provided arguments/frames (e.g., compared to arguments lacking facts), and it is perceived in biased ways once individuals form clear initial opinions (e.g., motivated reasoning). Our results provide insight into how individuals form opinions over time, and bring together literatures on information, framing, and motivated reasoning.

Firm-Specific Assets, Multinationality, and Financial Performance: A Meta-analytic Review and Theoretical Integration

Abstract: Through a meta-analysis of 120 independent samples reported in 111 studies, we test the predictions of internalization theory in the context of the multinationality-performance relationship. Findin...

Addiction as an Attachment Disorder

Abstract: Chapter 1 Foreword Chapter 2 Addiction as an Attachment Disorder Chapter 3 Substance Abuse as a Consequence of and Solution for Impaired Attachment Relationships Chapter 4 Attachment Theory: Implications for Treatment Chapter 5 Addiction: An Attempt at Self-Repair that Fails Chapter 6 Neurophysiology and Attachment Chapter 7 Avoidant Society: Cultural Roots of Impaired Attachment Chapter 8 Rules for Effective Treatment: An Attachment Perspective Chapter 9 Early Treatment: Creating the Capacity for Attachment Chapter 10 Late-Stage Treatment Issues Chapter 11 Attachment and Group Therapy Chapter 12 Attachment and the Therapeutic Alliance Chapter 13 Addiction and Attachment-Oriented Therapy: Long-Term Implications Chapter 14 Conclusions Chapter 15 References

Estimation of alternative splicing isoform frequencies from RNA-Seq data

Abstract: Massively parallel whole transcriptome sequencing, commonly referred as RNA-Seq, is quickly becoming the technology of choice for gene expression profiling. However, due to the short read length delivered by current sequencing technologies, estimation of expression levels for alternative splicing gene isoforms remains challenging. In this paper we present a novel expectation-maximization algorithm for inference of isoform- and gene-specific expression levels from RNA-Seq data. Our algorithm, referred to as IsoEM, is based on disambiguating information provided by the distribution of insert sizes generated during sequencing library preparation, and takes advantage of base quality scores, strand and read pairing information when available. The open source Java implementation of IsoEM is freely available at http://dna.engr.uconn.edu/software/IsoEM/ . Empirical experiments on both synthetic and real RNA-Seq datasets show that IsoEM has scalable running time and outperforms existing methods of isoform and gene expression level estimation. Simulation experiments confirm previous findings that, for a fixed sequencing cost, using reads longer than 25-36 bases does not necessarily lead to better accuracy for estimating expression levels of annotated isoforms and genes.

EXPLORING THE LOW-MASS END OF THE M BH-σ* RELATION WITH ACTIVE GALAXIES

Abstract: We present new measurements of stellar velocity dispersions, using spectra obtained with the Keck Echellette Spectrograph and Imager (ESI) and the Magellan Echellette (MagE), for 76 Seyfert 1 galaxies from the recent catalog of Greene and Ho. These objects were selected from the Sloan Digital Sky Survey (SDSS) to have estimated black hole (BH) masses below 2 x 10{sup 6} M{sub sun}. Combining our results with previous ESI observations of similar objects, we obtain an expanded sample of 93 galaxies and examine the relation between BH mass and velocity dispersion (the M{sub BH}-{sigma}{sub *} relation) for active galaxies with low BH masses. The low-mass active galaxies tend to follow the extrapolation of the M{sub BH}-{sigma}{sub *} relation of inactive galaxies. Including results for active galaxies of higher BH mass from the literature, we find a zero point {alpha} = 7.68 {+-} 0.08 and slope of {beta} = 3.32 {+-} 0.22 for the M{sub BH}-{sigma}{sub *} relation (in the form log M{sub BH} = {alpha} + {beta}log ({sigma}{sub *}/200 km s{sup -1})), with intrinsic scatter of 0.46 {+-} 0.03 dex. This result is consistent, within the uncertainties, with the slope of the M{sub BH}-{sigma}{sub *} relation for reverberation-mapped active galaxies withmore » BH masses from 10{sup 6} to 10{sup 9} M{sub sun}. For the subset of our sample having morphological information from Hubble Space Telescope images, we examine the slope of the M{sub BH}-{sigma}{sub *} relation separately for subsamples of barred and unbarred host galaxies, and find no significant evidence for a difference in slope. We do find a mild offset between low-inclination and high-inclination disk galaxies, such that more highly inclined galaxies tend to have larger {sigma}{sub *} at a given value of BH mass, presumably due to the contribution of disk rotation within the spectroscopic aperture. We also find that the velocity dispersion of the ionized gas, measured from narrow emission lines including [N II] {lambda}6583, [S II] {lambda}{lambda}6716, 6731, and the core of [O III] {lambda}5007 (with the blueshifted wing removed), trace the stellar velocity dispersion well for this large sample of low-mass Seyfert 1 galaxies.« less

Trajectories of emotional well-being in mothers of adolescents and adults with autism.

Abstract: Raising an adolescent or adult child with a developmental disability confers exceptional caregiving challenges on parents. We examined trajectories of 2 indicators of emotional well-being (depressive symptoms and anxiety) in a sample of primarily Caucasian mothers (N 379; Mage 51.22 years at Time 1) of adolescent and adult children with an autism spectrum disorder (ASD; Mage 21.91 years at Time 1, 73.2% male). We also investigated within-person associations of child context time-varying covariates (autism symptoms, behavior problems, residential status) and maternal context time-varying covariates (social support network size and stressful family events) with the trajectories of emotional well-being. Data were collected on 5 occasions across a 10-year period. Average patterns of stable (depressive symptoms) and improved (anxiety) emotional well-being were evident, and well-being trajectories were sensitive to fluctuations in both child and maternal context variables. On occasions when behavior problems were higher, depressive symptoms and anxiety were higher. On occasions after which the grown child moved out of the family home, anxiety was lower. Anxiety was higher on occasions when social support networks were smaller and when more stressful life events were experienced. These results have implications for midlife and aging families of children with an ASD and those who provide services to these families.

Maltodextrin-based imaging probes detect bacteria in vivo with high sensitivity and specificity.

Abstract: The in vivo optical detection of bacterial infections requires highly specific imaging probes with small affinity to mammalian tissue. It is now shown that fluorescent dyes that are conjugated to maltohexaose can be internalized rapidly via the bacteria-specific maltodextrin transport pathway, enabling the in vivo imaging of Escherichia coli down to 105 colony-forming units.

A Fast Hierarchical Clustering Algorithm for Functional Modules Discovery in Protein Interaction Networks

Abstract: As advances in the technologies of predicting protein interactions, huge data sets portrayed as networks have been available. Identification of functional modules from such networks is crucial for understanding principles of cellular organization and functions. However, protein interaction data produced by high-throughput experiments are generally associated with high false positives, which makes it difficult to identify functional modules accurately. In this paper, we propose a fast hierarchical clustering algorithm HC-PIN based on the local metric of edge clustering value which can be used both in the unweighted network and in the weighted network. The proposed algorithm HC-PIN is applied to the yeast protein interaction network, and the identified modules are validated by all the three types of Gene Ontology (GO) Terms: Biological Process, Molecular Function, and Cellular Component. The experimental results show that HC-PIN is not only robust to false positives, but also can discover the functional modules with low density. The identified modules are statistically significant in terms of three types of GO annotations. Moreover, HC-PIN can uncover the hierarchical organization of functional modules with the variation of its parameter's value, which is approximatively corresponding to the hierarchical structure of GO annotations. Compared to other previous competing algorithms, our algorithm HC-PIN is faster and more accurate.