Showing papers by "Georgia State University published in 2013"

Planetary Candidates Observed by Kepler. III. Analysis of the First 16 Months of Data

Abstract: New transiting planet candidates are identified in 16 months (2009 May-2010 September) of data from the Kepler spacecraft. Nearly 5000 periodic transit-like signals are vetted against astrophysical and instrumental false positives yielding 1108 viable new planet candidates, bringing the total count up to over 2300. Improved vetting metrics are employed, contributing to higher catalog reliability. Most notable is the noise-weighted robust averaging of multi-quarter photo-center offsets derived from difference image analysis that identifies likely background eclipsing binaries. Twenty-two months of photometry are used for the purpose of characterizing each of the candidates. Ephemerides (transit epoch, T_0, and orbital period, P) are tabulated as well as the products of light curve modeling: reduced radius (R_P/R_★), reduced semimajor axis (d/R_★), and impact parameter (b). The largest fractional increases are seen for the smallest planet candidates (201% for candidates smaller than 2 R_⊕ compared to 53% for candidates larger than 2 R_⊕) and those at longer orbital periods (124% for candidates outside of 50 day orbits versus 86% for candidates inside of 50 day orbits). The gains are larger than expected from increasing the observing window from 13 months (Quarters 1-5) to 16 months (Quarters 1-6) even in regions of parameter space where one would have expected the previous catalogs to be complete. Analyses of planet frequencies based on previous catalogs will be affected by such incompleteness. The fraction of all planet candidate host stars with multiple candidates has grown from 17% to 20%, and the paucity of short-period giant planets in multiple systems is still evident. The progression toward smaller planets at longer orbital periods with each new catalog release suggests that Earth-size planets in the habitable zone are forthcoming if, indeed, such planets are abundant.

The Low-luminosity End of the Radius-Luminosity Relationship for Active Galactic Nuclei

Abstract: We present an updated and revised analysis of the relationship between the H{beta} broad-line region (BLR) radius and the luminosity of the active galactic nucleus (AGN). Specifically, we have carried out two-dimensional surface brightness decompositions of the host galaxies of nine new AGNs imaged with the Hubble Space Telescope Wide Field Camera 3. The surface brightness decompositions allow us to create ''AGN-free'' images of the galaxies, from which we measure the starlight contribution to the optical luminosity measured through the ground-based spectroscopic aperture. We also incorporate 20 new reverberation-mapping measurements of the H{beta} time lag, which is assumed to yield the average H{beta} BLR radius. The final sample includes 41 AGNs covering four orders of magnitude in luminosity. The additions and updates incorporated here primarily affect the low-luminosity end of the R{sub BLR}-L relationship. The best fit to the relationship using a Bayesian analysis finds a slope of {alpha}= 0.533{sup +0.035}{sub -0.033}, consistent with previous work and with simple photoionization arguments. Only two AGNs appear to be outliers from the relationship, but both of them have monitoring light curves that raise doubt regarding the accuracy of their reported time lags. The scatter around the relationship is found to be 0.19more » {+-} 0.02 dex, but would be decreased to 0.13 dex by the removal of these two suspect measurements. A large fraction of the remaining scatter in the relationship is likely due to the inaccurate distances to the AGN host galaxies. Our results help support the possibility that the R{sub BLR}-L relationship could potentially be used to turn the BLRs of AGNs into standardizable candles. This would allow the cosmological expansion of the universe to be probed by a separate population of objects, and over a larger range of redshifts.« less

From resilience to resourcefulness: A critique of resilience policy and activism

Abstract: This paper provides a theoretical and political critique of how the concept of resilience has been applied to places. It is based upon three main points. First, the ecological concept of resilience...

Information Systems Success: The Quest for the Independent Variables

Abstract: In 1992, DeLone and McLean suggested that the dependent variable for information systems (IS) research is IS Success. Their research resulted in the widely cited DeLone and McLean (D&M) IS Success Model, in which System Quality, Information Quality, Use, User Satisfaction, Individual Impact, and Organizational Impact are distinct, but related dimensions of IS success. Since the original IS Success Model was published, research has developed a better understanding of IS success. Meanwhile, comprehensive and integrative research on the variables that influence IS success has been lacking. Therefore, we examine the literature on the independent variables that affect IS success. After examining over 600 articles, we focused our attention on integrating the findings of over 140 studies. In this research, we identify 43 specific variables posited to influence the different dimensions of IS success, and we organize these success factors into five categories based on the Leavitt Diamond of Organizational Change: ...

Cultural humility: measuring openness to culturally diverse clients.

Abstract: Building on recent theory stressing multicultural orientation, as well as the development of virtues and dispositions associated with multicultural values, we introduce the construct of cultural humility, defined as having an interpersonal stance that is other-oriented rather than self-focused, characterized by respect and lack of superiority toward an individual's cultural background and experience. In 4 studies, we provide evidence for the estimated reliability and construct validity of a client-rated measure of a therapist's cultural humility, and we demonstrate that client perceptions of their therapist's cultural humility are positively associated with developing a strong working alliance. Furthermore, client perceptions of their therapist's cultural humility were positively associated with improvement in therapy, and this relationship was mediated by a strong working alliance. We consider implications for research, practice, and training.

Optical-field-induced current in dielectrics

Abstract: Exposing a fused silica sample to a strong, waveform-controlled, few-cycle optical field increases the dielectric’s optical conductivity by more than 18 orders of magnitude in less than 1 femtosecond, allowing electric currents to be driven, directed and switched by the instantaneous light field. Two studies published in this issue highlight the potential for ultrafast signal manipulation in dielectrics using optical fields. When it comes to electrical signal processing, semiconductors have become the materials of choice. However, insulators such as dielectrics could be attractive alternatives: they have a fast response in principle, but usually have extremely low conductivity at low electric fields and break down in large fields. The electronic properties of dielectrics can be controlled with few-cycle laser pulses that permit damage-free exposure of dielectrics to high electric fields. Agustin Schiffrin et al. demonstrate that strong optical laser fields with controlled few-cycle waveforms can reversibly transform a dielectric insulator into a conductor within the optical period (within one femtosecond). Martin Schultze et al. address the crucial issue of ultrafast reversibility, demonstrating that the dielectric can be repeatedly switched 'on' and 'off' with light fields, without degradation. The time it takes to switch on and off electric current determines the rate at which signals can be processed and sampled in modern information technology1,2,3,4. Field-effect transistors1,2,3,5,6 are able to control currents at frequencies of the order of or higher than 100 gigahertz, but electric interconnects may hamper progress towards reaching the terahertz (1012 hertz) range. All-optical injection of currents through interfering photoexcitation pathways7,8,9,10 or photoconductive switching of terahertz transients11,12,13,14,15,16 has made it possible to control electric current on a subpicosecond timescale in semiconductors. Insulators have been deemed unsuitable for both methods, because of the need for either ultraviolet light or strong fields, which induce slow damage or ultrafast breakdown17,18,19,20, respectively. Here we report the feasibility of electric signal manipulation in a dielectric. A few-cycle optical waveform reversibly increases—free from breakdown—the a.c. conductivity of amorphous silicon dioxide (fused silica) by more than 18 orders of magnitude within 1 femtosecond, allowing electric currents to be driven, directed and switched by the instantaneous light field. Our work opens the way to extending electronic signal processing and high-speed metrology into the petahertz (1015 hertz) domain.

Controlling dielectrics with the electric field of light

Abstract: The ultrafast reversibility of changes to the electronic structure and electric polarizability of a dielectric with the electric field of a laser pulse, demonstrated here, offers the potential for petahertz-bandwidth optical signal manipulation. Two studies published in this issue highlight the potential for ultrafast signal manipulation in dielectrics using optical fields. When it comes to electrical signal processing, semiconductors have become the materials of choice. However, insulators such as dielectrics could be attractive alternatives: they have a fast response in principle, but usually have extremely low conductivity at low electric fields and break down in large fields. The electronic properties of dielectrics can be controlled with few-cycle laser pulses that permit damage-free exposure of dielectrics to high electric fields. Agustin Schiffrin et al. demonstrate that strong optical laser fields with controlled few-cycle waveforms can reversibly transform a dielectric insulator into a conductor within the optical period (within one femtosecond). Martin Schultze et al. address the crucial issue of ultrafast reversibility, demonstrating that the dielectric can be repeatedly switched 'on' and 'off' with light fields, without degradation. The control of the electric and optical properties of semiconductors with microwave fields forms the basis of modern electronics, information processing and optical communications. The extension of such control to optical frequencies calls for wideband materials such as dielectrics, which require strong electric fields to alter their physical properties1,2,3,4,5. Few-cycle laser pulses permit damage-free exposure of dielectrics to electric fields of several volts per angstrom6 and significant modifications in their electronic system6,7,8,9,10,11,12,13. Fields of such strength and temporal confinement can turn a dielectric from an insulating state to a conducting state within the optical period14. However, to extend electric signal control and processing to light frequencies depends on the feasibility of reversing these effects approximately as fast as they can be induced. Here we study the underlying electron processes with sub-femtosecond solid-state spectroscopy, which reveals the feasibility of manipulating the electronic structure and electric polarizability of a dielectric reversibly with the electric field of light. We irradiate a dielectric (fused silica) with a waveform-controlled near-infrared few-cycle light field of several volts per angstrom and probe changes in extreme-ultraviolet absorptivity and near-infrared reflectivity on a timescale of approximately a hundred attoseconds to a few femtoseconds. The field-induced changes follow, in a highly nonlinear fashion, the turn-on and turn-off behaviour of the driving field, in agreement with the predictions of a quantum mechanical model. The ultrafast reversibility of the effects implies that the physical properties of a dielectric can be controlled with the electric field of light, offering the potential for petahertz-bandwidth signal manipulation.

Targeted zwitterionic near-infrared fluorophores for improved optical imaging

Abstract: The signal-to-background ratio (SBR) is the key determinant of sensitivity, detectability and linearity in optical imaging. As signal strength is often constrained by fundamental limits, background reduction becomes an important approach for improving the SBR. We recently reported that a zwitterionic near-infrared (NIR) fluorophore, ZW800-1, exhibits low background. Here we show that this fluorophore provides a much-improved SBR when targeted to cancer cells or proteins by conjugation with a cyclic RGD peptide, fibrinogen or antibodies. ZW800-1 outperforms the commercially available NIR fluorophores IRDye800-CW and Cy5.5 in vitro for immunocytometry, histopathology and immunoblotting and in vivo for image-guided surgery. In tumor model systems, a tumor-to-background ratio of 17.2 is achieved at 4 h after injection of ZW800-1 conjugated to cRGD compared to ratios of 5.1 with IRDye800-CW and 2.7 with Cy5.5. Our results suggest that introducing zwitterionic properties into targeted fluorophores may be a general strategy for improving the SBR in diagnostic and therapeutic applications.

Investigating the Structure and Meaning of Public Service Motivation across Populations: Developing an International Instrument and Addressing Issues of Measurement Invariance

Abstract: The growth in international research on public service motivation (PSM) raises a number of important questions about the degree to which the theory and research developed in one country can contribute to our understanding of PSM in other counties. To help address this issue, this study revisits the conceptual and operational definitions of PSM to address weaknesses previously noted in the literature. Although some important steps have been taken to both improve and internationalize the PSM scale, this work has been done incrementally. In contrast, this study takes a more systematic and comprehensive approach by combining the efforts of international PSM scholars to develop and then test a revised measurement instrument for PSM in 12 countries. Although the resulting four dimensional 16-item measure of PSM reported here provides a better theoretical and empirical foundation for the measurement of PSM, our results suggest that the exact meaning and scaling of PSM dimensions are likely to differ across cultures and languages. These results raise serious concerns regarding the ability to develop a single universal scale of PSM, or making direct comparisons of PSM across countries. Its earlier versions were delivered at the Annual Conference of the European Group for Public Administration, Toulouse, France, September 8–10, 2010, and at the 11th National Public Management Research Conference at Syracuse University, Syracuse, NY, June 2–4, 2011. Address correspondence to the author at smook@

Banking Deregulation and Innovation

Abstract: We document empirical support for a key micro-level channel --- innovation by young, private firms --- through which financial sector deregulation affects economic growth. We find that intrastate banking deregulation, which increased the local market power of banks, decreased the level and risk of innovation by young, private firms. In contrast, interstate banking deregulation, which decreased the local market power of banks, increased the level and risk of innovation by young, private firms. These contrasting effects on innovation also translated into contrasting effects on economic growth. Our study suggests that the nature of financial sector deregulation crucially affects its potential benefits to the real economy.

The effectiveness of intervention programs for perpetrators and victims of intimate partner violence.

Abstract: ion of Data Four of the authors (CE, CM, RS, & KW) abstracted all study data. All study information and results were checked and confirmed by a senior author (CE or CM).

Language and literacy development of deaf and hard-of-hearing children: successes and challenges.

Abstract: Childhood hearing loss presents challenges to language development, especially spoken language In this article, we review existing literature on deaf and hard-of-hearing (DHH) children's patterns and trajectories of language as well as development of theory of mind and literacy Individual trajectories vary significantly, reflecting access to early identification/intervention, advanced technologies (eg, cochlear implants), and perceptually accessible language models DHH children develop sign language in a similar manner as hearing children develop spoken language, provided they are in a language-rich environment This occurs naturally for DHH children of deaf parents, who constitute 5% of the deaf population For DHH children of hearing parents, sign language development depends on the age that they are exposed to a perceptually accessible 1st language as well as the richness of input Most DHH children are born to hearing families who have spoken language as a goal, and such development is now feasible for many children Some DHH children develop spoken language in bilingual (sign-spoken language) contexts For the majority of DHH children, spoken language development occurs in either auditory-only contexts or with sign supports Although developmental trajectories of DHH children with hearing parents have improved with early identification and appropriate interventions, the majority of children are still delayed compared with hearing children These DHH children show particular weaknesses in the development of grammar Language deficits and differences have cascading effects in language-related areas of development, such as theory of mind and literacy development

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 to examine 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 prosocial messages or technical information alone. Moreover, our data suggest that 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 nonpecuniary strategies.

Stellar diameters and temperatures. iii. main-sequence a, f, g, and k stars: additional high-precision measurements and empirical relations

Abstract: Based on CHARA Array measurements, we present the angular diameters of 23 nearby, main-sequence stars, ranging from spectral types A7 to K0, 5 of which are exoplanet host stars. We derive linear radii, effective temperatures, and absolute luminosities of the stars using Hipparcos parallaxes and measured bolometric fluxes. The new data are combined with previously published values to create an Angular Diameter Anthology of measured angular diameters to main-sequence stars (luminosity classes V and IV). This compilation consists of 125 stars with diameter uncertainties of less than 5%, ranging in spectral types from A to M. The large quantity of empirical data is used to derive color-temperature relations to an assortment of color indices in the Johnson (BVR_(J)I_(J)JHK), Cousins (R_(C)I_(C)), Kron (R_(K)I_(K)), Sloan (griz), and WISE (W_(3)W_(4)) photometric systems. These relations have an average standard deviation of ~3% and are valid for stars with spectral types A0-M4. To derive even more accurate relations for Sun-like stars, we also determined these temperature relations omitting early-type stars (T_eff > 6750 K) that may have biased luminosity estimates because of rapid rotation; for this subset the dispersion is only ~2.5%. We find effective temperatures in agreement within a couple of percent for the interferometrically characterized sample of main-sequence stars compared to those derived via the infrared flux method and spectroscopic analysis.

Determining inclinations of active galactic nuclei via their narrow-line region kinematics. i. observational results*

Abstract: Active galactic nuclei (AGNs) are axisymmetric systems to first order; their observed properties are likely strong functions of inclination with respect to our line of sight (LOS). However, except for a few special cases, the specific inclinations of individual AGNs are unknown. We have developed a promising technique for determining the inclinations of nearby AGNs by mapping the kinematics of their narrow-line regions (NLRs), which are often easily resolved with Hubble Space Telescope [O III] imaging and long-slit spectra from the Space Telescope Imaging Spectrograph. Our studies indicate that NLR kinematics dominated by radial outflow can be fit with simple biconical outflow models that can be used to determine the inclination of the bicone axis, and hence the obscuring torus, with respect to our LOS. We present NLR analysis of 53 Seyfert galaxies and the resulting inclinations from models of 17 individual AGNs with clear signatures of biconical outflows. Our model results agree with the unified model in that Seyfert 1 AGNs have NLRs inclined further toward our LOS than Seyfert 2 AGNs. Knowing the inclinations of these AGN NLRs, and thus their accretion disk and/or torus axes, will allow us to determine how their observed properties vary as a function of polar angle. We find no correlation between the inclinations of the AGN NLRs and the disks of their host galaxies, indicating that the orientation of the gas in the torus is independent of that of the host disk.

Quadrupole anisotropy in dihadron azimuthal correlations in central d+Au collisions at √sNN=200 GeV

Abstract: The PHENIX collaboration at the Relativistic Heavy Ion Collider (RHIC) reports measurements of azimuthal dihadron correlations near midrapidity in d + Au collisions at root s(NN) = 200 GeV. These measurements complement recent analyses by experiments at the Large Hadron Collider (LHC) involving central p + Pb collisions at root s(NN) = 5.02 TeV, which have indicated strong anisotropic long-range correlations in angular distributions of hadron pairs. The origin of these anisotropies is currently unknown. Various competing explanations include parton saturation and hydrodynamic flow. We observe qualitatively similar, but larger, anisotropies in d + Au collisions at RHIC compared to those seen in p + Pb collisions at the LHC. The larger extracted upsilon(2) values in d + Au are consistent with expectations from hydrodynamic calculations owing to the larger expected initial-state eccentricity compared with that from p + Pb collisions. When both are divided by an estimate of the initial-state eccentricity the scaled anisotropies follow a common trend with multiplicity that may extend to heavy ion data at RHIC and the LHC, where the anisotropies are widely thought to arise from hydrodynamic flow.

Defining Social Enterprise Across Different Contexts A Conceptual Framework Based on Institutional Factors

Abstract: Over the past several decades the concept of social enterprise has grown dramatically in many regions of the world. Defined as the use of nongovernmental, market-based approaches to address social issues, social enterprise often provides a ‘business’ source of revenue for many types of socially oriented organizations and activities.1 However, within these broad parameters, world regions have come to identify different definitions and concepts with the social enterprise movement in their areas (Kerlin, 2006). This variation has also resulted in considerable debate among researchers and practitioners on how to define the concept (Mair et al., 2006; Light, 2008). To address these difficulties, this research draws on the theory of historical institutionalism to advance understanding of how context influences the development of social enterprise as well as to propose a preliminary conceptual framework for social enterprise that spans regional differences in the term.

Virtual reality exposure therapy for social anxiety disorder: a randomized controlled trial.

Abstract: Objective This is the first randomized trial comparing virtual reality exposure therapy to in vivo exposure for social anxiety disorder. Method Participants with a principal diagnosis of social anxiety disorder who identified public speaking as their primary fear (N = 97) were recruited from the community, resulting in an ethnically diverse sample (M age = 39 years) of mostly women (62%). Participants were randomly assigned to and completed 8 sessions of manualized virtual reality exposure therapy, exposure group therapy, or wait list. Standardized self-report measures were collected at pretreatment, posttreatment, and 12-month follow-up, and process measures were collected during treatment. A standardized speech task was delivered at pre- and posttreatment, and diagnostic status was reassessed at 3-month follow-up. Results Analysis of covariance showed that, relative to wait list, people completing either active treatment significantly improved on all but one measure (length of speech for exposure group therapy and self-reported fear of negative evaluation for virtual reality exposure therapy). At 12-month follow-up, people showed significant improvement from pretreatment on all measures. There were no differences between the active treatments on any process or outcome measure at any time, nor differences on achieving partial or full remission. Conclusion Virtual reality exposure therapy is effective for treating social fears, and improvement is maintained for 1 year. Virtual reality exposure therapy is equally effective as exposure group therapy; further research with a larger sample is needed, however, to better control and statistically test differences between the treatments.

Motivational Differences Across Post-Acceptance Information System Usage Behaviors: An Investigation in the Business Intelligence Systems Context

Abstract: We identify two post-acceptance information system (IS) usage behaviors related to how employees leverage implemented systems. Routine use (RTN) refers to employees' using IS in a routine and standardized manner to support their work, and innovative use (INV) describes employees' discovering new ways to use IS to support their work. We use motivation theory as the overarching perspective to explain RTN and INV and appropriate the rich intrinsic motivation (RIM) concept from social psychology to propose a conceptualization of RIM toward IS use, which includes intrinsic motivation toward accomplishment (IMap), intrinsic motivation to know (IMkw), and intrinsic motivation to experience stimulation (IMst). We also consider the influence of perceived usefulness (PU)—a representative surrogate construct of extrinsic motivation toward IS use—on RTN and INV. We theorize the relative impacts of the RIM constructs and PU on RTN and INV and the role of personal innovativeness with IT (PIIT) in moderating the RIM con...

Stellar velocity dispersion measurements in high-luminosity quasar hosts and implications for the agn black hole mass scale

Abstract: We present new stellar velocity dispersion measurements for four luminous quasars with the Near-Infrared Integral Field Spectrometer instrument and the ALTAIR laser guide star adaptive optics system on the Gemini North 8 m telescope. Stellar velocity dispersion measurements and measurements of the supermassive black hole (BH) masses in luminous quasars are necessary to investigate the coevolution of BHs and galaxies, trace the details of accretion, and probe the nature of feedback. We find that higher-luminosity quasars with higher-mass BHs are not offset with respect to the M BH-σ* relation exhibited by lower-luminosity active galactic nuclei (AGNs) with lower-mass BHs, nor do we see correlations with galaxy morphology. As part of this analysis, we have recalculated the virial products for the entire sample of reverberation-mapped AGNs and used these data to redetermine the mean virial factor f that places the reverberation data on the quiescent M BH-σ* relation. With our updated measurements and new additions to the AGN sample, we obtain f = 4.31 ± 1.05, which is slightly lower than, but consistent with, most previous determinations.

The structure of the broad-line region in active galactic nuclei. I. Reconstructed velocity-delay maps

Abstract: We present velocity-resolved reverberation results for five active galactic nuclei. We recovered velocity-delay maps using the maximum entropy method for four objects: Mrk 335, Mrk 1501, 3C?120, and PG?2130+099. For the fifth, Mrk 6, we were only able to measure mean time delays in different velocity bins of the H? emission line. The four velocity-delay maps show unique dynamical signatures for each object. For 3C?120, the Balmer lines show kinematic signatures consistent with both an inclined disk and infalling gas, but the He II??4686 emission line is suggestive only of inflow. The Balmer lines in Mrk 335, Mrk 1501, and PG?2130+099 show signs of infalling gas, but the He II emission in Mrk 335 is consistent with an inclined disk. We also see tentative evidence of combined virial motion and infalling gas from the velocity-binned analysis of Mrk 6. The maps for 3C?120 and Mrk 335 are two of the most clearly defined velocity-delay maps to date. These maps constitute a large increase in the number of objects for which we have resolved velocity-delay maps and provide evidence supporting the reliability of reverberation-based black hole mass measurements.

Large-Scale Use of the Modified Checklist for Autism in Low-Risk Toddlers

Abstract: OBJECTIVE: The purpose of the study was to examine use of the Modified Checklist for Autism in Toddlers (M-CHAT) as an autism-specific screening instrument in a large, geographically diverse pediatrics-based sample. METHODS: The M-CHAT and the M-CHAT Follow-Up (M-CHAT/F) were used to screen 18 989 toddlers at pediatric well-child visits in 2 US geographic regions. Pediatricians directly referred children to ascertain potential missed screening cases. Screen-positive children received the M-CHAT/F; children who continued to screen positive after the M-CHAT/F received a diagnostic evaluation. RESULTS: Results indicated that 54% of children who screened positive on the M-CHAT and M-CHAT/F presented with an autism spectrum disorder (ASD), and 98% presented with clinically significant developmental concerns warranting intervention. An M-CHAT total score cutoff of ≥3 identifies nearly all screen-positive cases, and for ease of scoring the use of only the M-CHAT total score cutoff is recommended. An M-CHAT total score of 7 serves as an appropriate clinical cutoff, and providers can bypass the M-CHAT/F and refer immediately to evaluation and intervention if a child obtains a score of ≥7. CONCLUSIONS: This study provides empirical support for the utility of population screening for ASD with the use of the M-CHAT in a primary care setting. Results suggest that the M-CHAT continues to be an effective screening instrument for ASD when the 2-step screening process is used. The M-CHAT is widely used at pediatric offices, and this study provides updated results to facilitate use and scoring of the M-CHAT by clinical providers.

Citizen, Customer, Partner: Rethinking the Place of the Public in Public Management

Abstract: Scholars and practitioners have long debated what role the public should play in public management. When members of the public interact with the administrative side of government, should they be treated as customers, as citizens, or in some other manner? This article takes as its premise that members of the public assume three principal roles relative to public management: as customers, as partners, and as citizens. After placing these roles in the context of the history of public administration, the article draws from recent research to recommend guidelines for how public managers can work effectively with the public in these several capacities.

b-SPECS+: Batch Verification for Secure Pseudonymous Authentication in VANET

Abstract: The security and privacy preservation issues are prerequisites for vehicular ad hoc networks. Recently, secure and privacy enhancing communication schemes (SPECS) was proposed and focused on intervehicle communications. SPECS provided a software-based solution to satisfy the privacy requirement and gave lower message overhead and higher successful rate than previous solutions in the message verification phase. SPECS also presented the first group communication protocol to allow vehicles to authenticate and securely communicate with others in a group of known vehicles. Unfortunately, we find out that SPECS is vulnerable to impersonation attack. SPECS has a flow such that a malicious vehicle can force arbitrary vehicles to broadcast fake messages to other vehicles or even a malicious vehicle in the group can counterfeit another group member to send fake messages securely among themselves. In this paper, we provide a secure scheme that can achieve the security and privacy requirements, and overcome the weaknesses of SPECS. Moreover, we show the efficiency merits of our scheme through performance evaluations in terms of verification delay and transmission overhead.