Showing papers by "Pennsylvania State University published in 2009"

Understanding biophysicochemical interactions at the nano–bio interface

Abstract: Rapid growth in nanotechnology is increasing the likelihood of engineered nanomaterials coming into contact with humans and the environment. Nanoparticles interacting with proteins, membranes, cells, DNA and organelles establish a series of nanoparticle/biological interfaces that depend on colloidal forces as well as dynamic biophysicochemical interactions. These interactions lead to the formation of protein coronas, particle wrapping, intracellular uptake and biocatalytic processes that could have biocompatible or bioadverse outcomes. For their part, the biomolecules may induce phase transformations, free energy releases, restructuring and dissolution at the nanomaterial surface. Probing these various interfaces allows the development of predictive relationships between structure and activity that are determined by nanomaterial properties such as size, shape, surface chemistry, roughness and surface coatings. This knowledge is important from the perspective of safe use of nanomaterials.

The Seventh Data Release of the Sloan Digital Sky Survey

Abstract: This paper describes the Seventh Data Release of the Sloan Digital Sky Survey (SDSS), marking the completion of the original goals of the SDSS and the end of the phase known as SDSS-II. It includes 11,663 deg^2 of imaging data, with most of the ~2000 deg^2 increment over the previous data release lying in regions of low Galactic latitude. The catalog contains five-band photometry for 357 million distinct objects. The survey also includes repeat photometry on a 120° long, 2°.5 wide stripe along the celestial equator in the Southern Galactic Cap, with some regions covered by as many as 90 individual imaging runs. We include a co-addition of the best of these data, going roughly 2 mag fainter than the main survey over 250 deg^2. The survey has completed spectroscopy over 9380 deg^2; the spectroscopy is now complete over a large contiguous area of the Northern Galactic Cap, closing the gap that was present in previous data releases. There are over 1.6 million spectra in total, including 930,000 galaxies, 120,000 quasars, and 460,000 stars. The data release includes improved stellar photometry at low Galactic latitude. The astrometry has all been recalibrated with the second version of the USNO CCD Astrograph Catalog, reducing the rms statistical errors at the bright end to 45 milliarcseconds per coordinate. We further quantify a systematic error in bright galaxy photometry due to poor sky determination; this problem is less severe than previously reported for the majority of galaxies. Finally, we describe a series of improvements to the spectroscopic reductions, including better flat fielding and improved wavelength calibration at the blue end, better processing of objects with extremely strong narrow emission lines, and an improved determination of stellar metallicities.

Missing data analysis: making it work in the real world.

Abstract: This review presents a practical summary of the missing data literature, including a sketch of missing data theory and descriptions of normalmodel multiple imputation (MI) and maximum likelihood methods. Practical missing data analysis issues are discussed, most notably the inclusion of auxiliary variables for improving power and reducing bias. Solutions are given for missing data challenges such as handling longitudinal, categorical, and clustered data with normal-model MI; including interactions in the missing data model; and handling large numbers of variables. The discussion of attrition and nonignorable missingness emphasizes the need for longitudinal diagnostics and for reducing the uncertainty about the missing data mechanism under attrition. Strategies suggested for reducing attrition bias include using auxiliary variables, collecting follow-up data on a sample of those initially missing, and collecting data on intent to drop out. Suggestions are given for moving forward with research on missing data and attrition.

Latent Class and Latent Transition Analysis: With Applications in the Social, Behavioral, and Health Sciences

Abstract: List of Figures. List of Tables. Acknowledgments. Acronyms. Part I Fundamentals. 1. General Introduction. 1.1 Overview. 1.2 Conceptual foundation and brief history of the latent class model. 1.3 Why select a categorical latent variable approach? 1.4 Scope of this book. 1.5 Empirical example of LCA: Adolescent delinquency. 1.6 Empirical example of LTA: Adolescent delinquency. 1.7 About this book. 1.8 The examples in this book. 1.9 Software. 1.10 Additional resources: The book's web site. 1.11 Suggested supplemental readings. 1.12 Points to remember. 1.13 What's next. 2. The latent class model. 2.1 Overview. 2.2 Empirical example: Pubertal development. 2.3 The role of item-response probabilities to label the latent classes in the pubertal development example. 2.4 Empirical example: Health risk behaviors. 2.5 LCA: Model and notation. 2.6 Suggested supplemental readings. 2.7 Points to remember. 2.8 What's next. 3. The relation between the latent variable and its indicators. 3.1 Overview. 3.2 The latent class measurement model. 3.3 Homogeneity and latent class separation. 3.4 The precision with which the observed variables measure the latent variable. 3.5 Expressing the degree of uncertainty: Mean posterior probabilities and entropy. 3.6 Points to remember. 3.7 What's next. 4. Parameter estimation and model selection. 4.1 Overview. 4.2 Maximum Likelihood estimation. 4.3 Model fit and model selection. 4.4 Finding the ML solution. 4.5 Empirical example of using many starting values. 4.6 Empirical examples of selecting the number of latent classes. 4.7 More about parameter restrictions. 4.8 Standard errors. 4.9 Suggested supplemental readings. 4.10 Points to remember. 4.11 What's next. Part II Advanced LCA. 5. Multiple-group LCA. 5.1 Overview. 5.2 Introduction. 5.3 Multiple-group LCA: Model and notation. 5.4 Computing the number of parameters estimated. 5.5 Expressing group differences in the LCA model. 5.6 Measurement invariance. 5.7 Establishing whether the number of latent classes is identical across groups. 5.8 Establishing invariance of item-response probabilities across groups. 5.9 Interpretation when measurement invariance does not hold. 5.10 Strategies when measurement invariance does not hold. 5.11 Significant differences and important differences. 5.12 Testing equivalence of latent class prevalences across groups. 5.13 Suggested supplemental readings. 5.14 Points to remember. 5.15 What's next. 6. LCA with Covariates. 6.1 Overview. 6.2 Empirical example: Positive health behaviors. 6.3 Preparing to conduct LCA with covariates. 6.4 LCA with covariates: Model and notation. 6.5 Hypothesis testing in LCA with covariates. 6.6 Interpretation of the intercepts and regression coefficients. 6.7 Empirical examples of LCA with a single covariate. 6.8 Empirical example of multiple covariates and interaction terms. 6.9 Multiple-group LCA with covariates: Model and notation. 6.10 Grouping variable or covariate? 6.11 Use of a Bayesian prior to stabilize estimation. 6.12 Binomial logistic regression. 6.13 Suggested supplemental readings. 6.14 Points to remember. 6.15 What's next. Part III Latent Class Models for Longitudinal Data. 7. RMLCA and LTA. 7.1 Overview. 7.2 RMLCA. 7.3 LTA. 7.4 LTA model parameters. 7.5 LTA: Model and notation. 7.6 Degrees of freedom associated with latent transition models. 7.7 Empirical example: Adolescent depression. 7.8 Empirical example: Dating and sexual risk behavior. 7.9 Interpreting what a latent transition model reveals about change. 7.10 Parameter restrictions in LTA. 7.11 Testing the hypotheses of measurement invariance across times. 7.12 Testing the hypotheses about change between times. 7.13 Relation between RMLCA and LTA. 7.14 Invariance of the transition probability matrix. 7.15 Suggested supplemental readings. 7.16 Points to remember. 7.17 What's next. 8. Multiple-Group LTA and LTA with Covariates. 8.1 Overview. 8.2 LTA with a grouping variable. 8.3 Multiple-group LTA: Model and notation. 8.4 Computing the number of parameters estimated in multiple-group latent transition models. 8.5 Hypothesis tests concerning group differences: General consideration. 8.6 Overall hypothesis tests about group differences in LTA. 8.7 Testing the hypothesis of equality of latent status prevalences. 8.8 Testing the hypothesis of equality of transition probabilities. 8.9 Incorporating covariates in LTA. 8.10 LTA with covariates: Model and notation. 8.11 Hypothesis testing in LTA with covariates. 8.12 Including both a grouping variable and a covariate in LTA. 8.13 Binomial logistic regression. 8.14 The relation between multiple-group LTA and LTA with a covariate. 8.15 Suggested supplemental readings. 8.16 Points to remember. Topic Index. Author Index.

Exoelectrogenic bacteria that power microbial fuel cells

Abstract: The use of microbial fuel cells to generate electrical current is increasingly being seen as a viable source of renewable energy production In this Progress article, Bruce Logan highlights recent advances in our understanding of the mechanisms used by exoelectrogenic bacteria to generate electrical current and the important factors to consider in microbial fuel cell design There has been an increase in recent years in the number of reports of microorganisms that can generate electrical current in microbial fuel cells Although many new strains have been identified, few strains individually produce power densities as high as strains from mixed communities Enriched anodic biofilms have generated power densities as high as 69 W per m2 (projected anode area), and therefore are approaching theoretical limits To understand bacterial versatility in mechanisms used for current generation, this Progress article explores the underlying reasons for exocellular electron transfer, including cellular respiration and possible cell–cell communication

Metabolomic profiles delineate potential role for sarcosine in prostate cancer progression

Abstract: Multiple, complex molecular events characterize cancer development and progression. Deciphering the molecular networks that distinguish organ-confined disease from metastatic disease may lead to the identification of critical biomarkers for cancer invasion and disease aggressiveness. Although gene and protein expression have been extensively profiled in human tumours, little is known about the global metabolomic alterations that characterize neoplastic progression. Using a combination of high-throughput liquid-and-gas-chromatography-based mass spectrometry, we profiled more than 1,126 metabolites across 262 clinical samples related to prostate cancer (42 tissues and 110 each of urine and plasma). These unbiased metabolomic profiles were able to distinguish benign prostate, clinically localized prostate cancer and metastatic disease. Sarcosine, an N-methyl derivative of the amino acid glycine, was identified as a differential metabolite that was highly increased during prostate cancer progression to metastasis and can be detected non-invasively in urine. Sarcosine levels were also increased in invasive prostate cancer cell lines relative to benign prostate epithelial cells. Knockdown of glycine-N-methyl transferase, the enzyme that generates sarcosine from glycine, attenuated prostate cancer invasion. Addition of exogenous sarcosine or knockdown of the enzyme that leads to sarcosine degradation, sarcosine dehydrogenase, induced an invasive phenotype in benign prostate epithelial cells. Androgen receptor and the ERG gene fusion product coordinately regulate components of the sarcosine pathway. Here, by profiling the metabolomic alterations of prostate cancer progression, we reveal sarcosine as a potentially important metabolic intermediary of cancer cell invasion and aggressivity.

Global Signatures and Dynamical Origins of the Little Ice Age and Medieval Climate Anomaly

Abstract: Global temperatures are known to have varied over the past 1500 years, but the spatial patterns have remained poorly defined. We used a global climate proxy network to reconstruct surface temperature patterns over this interval. The Medieval period is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally. This period is marked by a tendency for La Nina-like conditions in the tropical Pacific. The coldest temperatures of the Little Ice Age are observed over the interval 1400 to 1700 C.E., with greatest cooling over the extratropical Northern Hemisphere continents. The patterns of temperature change imply dynamical responses of climate to natural radiative forcing changes involving El Nino and the North Atlantic Oscillation-Arctic Oscillation.

The role of dynamic conformational ensembles in biomolecular recognition

Abstract: Molecular recognition is central to all biological processes. For the past 50 years, Koshland's 'induced fit' hypothesis has been the textbook explanation for molecular recognition events. However, recent experimental evidence supports an alternative mechanism. 'Conformational selection' postulates that all protein conformations pre-exist, and the ligand selects the most favored conformation. Following binding the ensemble undergoes a population shift, redistributing the conformational states. Both conformational selection and induced fit appear to play roles. Following binding by a primary conformational selection event, optimization of side chain and backbone interactions is likely to proceed by an induced fit mechanism. Conformational selection has been observed for protein-ligand, protein-protein, protein-DNA, protein-RNA and RNA-ligand interactions. These data support a new molecular recognition paradigm for processes as diverse as signaling, catalysis, gene regulation and protein aggregation in disease, which has the potential to significantly impact our views and strategies in drug design, biomolecular engineering and molecular evolution.

Methods and results of an automatic analysis of a complete sample of Swift-XRT observations of GRBs

Abstract: We present a homogeneous X-ray analysis of all 318 gamma-ray bursts detected by the X-ray telescope (XRT) on the Swift satellite up to 2008 July 23; this represents the largest sample of X-ray GRB data published to date. In Sections 2-3, we detail the methods which the Swift-XRT team has developed to produce the enhanced positions, light curves, hardness ratios and spectra presented in this paper. Software using these methods continues to create such products for all new GRBs observed by the Swift-XRT. We also detail web-based tools allowing users to create these products for any object observed by the XRT, not just GRBs. In Sections 4-6, we present the results of our analysis of GRBs, including probability distribution functions of the temporal and spectral properties of the sample. We demonstrate evidence for a consistent underlying behaviour which can produce a range of light-curve morphologies, and attempt to interpret this behaviour in the framework of external forward shock emission. We find several difficulties, in particular that reconciliation of our data with the forward shock model requires energy injection to continue for days to weeks.

Widespread increase of tree mortality rates in the western United States

Abstract: Persistent changes in tree mortality rates can alter forest structure, composition, and ecosystem services such as carbon sequestration. Our analyses of longitudinal data from unmanaged old forests in the western United States showed that background (noncatastrophic) mortality rates have increased rapidly in recent decades, with doubling periods ranging from 17 to 29 years among regions. Increases were also pervasive across elevations, tree sizes, dominant genera, and past fire histories. Forest density and basal area declined slightly, which suggests that increasing mortality was not caused by endogenous increases in competition. Because mortality increased in small trees, the overall increase in mortality rates cannot be attributed solely to aging of large trees. Regional warming and consequent increases in water deficits are likely contributors to the increases in tree mortality rates.

The Clinical Course of Advanced Dementia

Abstract: BACKGROUND Dementia is a leading cause of death in the United States but is underrecognized as a terminal illness. The clinical course of nursing home residents with advanced dementia has not been well described. METHODS We followed 323 nursing home residents with advanced dementia and their health care proxies for 18 months in 22 nursing homes. Data were collected to characterize the residents' survival, clinical complications, symptoms, and treatments and to determine the proxies' understanding of the residents' prognosis and the clinical complications expected in patients with advanced dementia. RESULTS Over a period of 18 months, 54.8% of the residents died. The probability of pneumonia was 41.1%; a febrile episode, 52.6%; and an eating problem, 85.8%. After adjustment for age, sex, and disease duration, the 6-month mortality rate for residents who had pneumonia was 46.7%; a febrile episode, 44.5%; and an eating problem, 38.6%. Distressing symptoms, including dyspnea (46.0%) and pain (39.1%), were common. In the last 3 months of life, 40.7% of residents underwent at least one burdensome intervention (hospitalization, emergency room visit, parenteral therapy, or tube feeding). Residents whose proxies had an understanding of the poor prognosis and clinical complications expected in advanced dementia were much less likely to have burdensome interventions in the last 3 months of life than were residents whose proxies did not have this understanding (adjusted odds ratio, 0.12; 95% confidence interval, 0.04 to 0.37). CONCLUSIONS Pneumonia, febrile episodes, and eating problems are frequent complications in patients with advanced dementia, and these complications are associated with high 6-month mortality rates. Distressing symptoms and burdensome interventions are also common among such patients. Patients with health care proxies who have an understanding of the prognosis and clinical course are likely to receive less aggressive care near the end of life.

OR FORUM---The Evolution of Closed-Loop Supply Chain Research

Abstract: The purpose of this paper is to introduce the reader to the field of closed-loop supply chains with a strong business perspective, i.e., we focus on profitable value recovery from returned products. It recounts the evolution of research in this growing area over the past 15 years, during which it developed from a narrow, technically focused niche area to a fully recognized subfield of supply chain management. We use five phases to paint an encompassing view of this evolutionary process for the reader to understand past achievements and potential future operations research opportunities.

Histone hypercitrullination mediates chromatin decondensation and neutrophil extracellular trap formation

Abstract: Peripheral blood neutrophils form highly decondensed chromatin structures, termed neutrophil extracellular traps (NETs), that have been implicated in innate immune response to bacterial infection. Neutrophils express high levels of peptidylarginine deiminase 4 (PAD4), which catalyzes histone citrullination. However, whether PAD4 or histone citrullination plays a role in chromatin structure in neutrophils is unclear. In this study, we show that the hypercitrullination of histones by PAD4 mediates chromatin decondensation. Histone hypercitrullination is detected on highly decondensed chromatin in HL-60 granulocytes and blood neutrophils. The inhibition of PAD4 decreases histone hypercitrullination and the formation of NET-like structures, whereas PAD4 treatment of HL-60 cells facilitates these processes. The loss of heterochromatin and multilobular nuclear structures is detected in HL-60 granulocytes after PAD4 activation. Importantly, citrullination of biochemically defined avian nucleosome arrays inhibits their compaction by the linker histone H5 to form higher order chromatin structures. Together, these results suggest that histone hypercitrullination has important functions in chromatin decondensation in granulocytes/neutrophils.

Ecological Dynamics Across the Arctic Associated with Recent Climate Change

Abstract: At the close of the Fourth International Polar Year, we take stock of the ecological consequences of recent climate change in the Arctic, focusing on effects at population, community, and ecosystem scales. Despite the buffering effect of landscape heterogeneity, Arctic ecosystems and the trophic relationships that structure them have been severely perturbed. These rapid changes may be a bellwether of changes to come at lower latitudes and have the potential to affect ecosystem services related to natural resources, food production, climate regulation, and cultural integrity. We highlight areas of ecological research that deserve priority as the Arctic continues to warm.

Colony Collapse Disorder: A Descriptive Study

Abstract: Background: Over the last two winters, there have been large-scale, unexplained losses of managed honey bee (Apis mellifera L.) colonies in the United States. In the absence of a known cause, this syndrome was named Colony Collapse Disorder (CCD) because the main trait was a rapid loss of adult worker bees. We initiated a descriptive epizootiological study in order to better characterize CCD and compare risk factor exposure between populations afflicted by and not afflicted by CCD. Methods and Principal Findings: Of 61 quantified variables (including adult bee physiology, pathogen loads, and pesticide levels), no single measure emerged as a most-likely cause of CCD. Bees in CCD colonies had higher pathogen loads and were co-infected with a greater number of pathogens than control populations, suggesting either an increased exposure to pathogens or a reduced resistance of bees toward pathogens. Levels of the synthetic acaricide coumaphos (used by beekeepers to control the parasitic mite Varroa destructor) were higher in control colonies than CCD-affected colonies. Conclusions/Significance: This is the first comprehensive survey of CCD-affected bee populations that suggests CCD involves an interaction between pathogens and other stress factors. We present evidence that this condition is contagious or the result of exposure to a common risk factor. Potentially important areas for future hypothesis-driven research, including the possible legacy effect of mite parasitism and the role of honey bee resistance to pesticides, are highlighted.

SEGUE: A SPECTROSCOPIC SURVEY OF 240,000 STARS WITH g = 14-20

Abstract: The Sloan Extension for Galactic Understanding and Exploration (SEGUE) Survey obtained {approx}240,000 moderate-resolution (R {approx} 1800) spectra from 3900 {angstrom} to 9000 {angstrom} of fainter Milky Way stars (14.0 10 per resolution element, stellar atmospheric parameters are estimated, including metallicity, surface gravity, and effective temperature. SEGUE obtained 3500 deg{sup 2} of additional ugriz imaging (primarily at low Galactic latitudes) providing precise multicolor photometry ({sigma}(g, r, i) {approx} 2%), ({sigma}(u, z) {approx} 3%) and astrometry ({approx}0.1) for spectroscopic target selection. The stellar spectra, imaging data, and derived parameter catalogs for this survey are publicly available as part of Sloan Digital Sky Survey Data Release 7.

Security and Privacy Challenges in the Smart Grid

Abstract: Global electrical grids are verging on the largest technological transformation since the introduction of electricity into the home. The antiquated infrastructure that delivers power to our homes and businesses is being replaced with a collection of digital systems called the smart grid. This grid is the modernization of the existing electrical system that enhances customers' and utilities' ability to monitor, control, and predict energy use.

mixtools: An R Package for Analyzing Finite Mixture Models

Abstract: The mixtools package for R provides a set of functions for analyzing a variety of nite mixture models. These functions include both traditional methods, such as EM algorithms for univariate and multivariate normal mixtures, and newer methods that reect some recent research in nite mixture models. In the latter category, mixtools provides algorithms for estimating parameters in a wide range of dierent mixture-of-regression contexts, in multinomial mixtures such as those arising from discretizing continuous multivariate data, in nonparametric situations where the multivariate component densities are completely unspecied, and in semiparametric situations such as a univariate location mixture of symmetric but otherwise unspecied densities. Many of the algorithms of the mixtools package are EM algorithms or are based on EM-like ideas, so this article includes an overview of EM algorithms for nite mixture models.

Polyploidy and angiosperm diversification

Abstract: Polyploidy has long been recognized as a major force in angiosperm evolution. Recent genomic investigations not only indicate that polyploidy is ubiquitous among angiosperms, but also suggest several ancient genome-doubling events. These include ancient whole genome duplication (WGD) events in basal angiosperm lineages, as well as a proposed paleohexaploid event that may have occurred close to the eudicot divergence. However, there is currently no evidence for WGD in Amborella, the putative sister species to other extant angiosperms. The question is no longer "What proportion of angiosperms are polyploid?", but "How many episodes of polyploidy characterize any given lineage?" New algorithms provide promise that ancestral genomes can be reconstructed for deep divergences (e.g., it may be possible to reconstruct the ancestral eudicot or even the ancestral angiosperm genome). Comparisons of diversification rates suggest that genome doubling may have led to a dramatic increase in species richness in several angiosperm lineages, including Poaceae, Solanaceae, Fabaceae, and Brassicaceae. However, additional genomic studies are needed to pinpoint the exact phylogenetic placement of the ancient polyploidy events within these lineages and to determine when novel genes resulting from polyploidy have enabled adaptive radiations.

A Strain-Driven Morphotropic Phase Boundary in BiFeO3

Abstract: Piezoelectric materials, which convert mechanical to electrical energy and vice versa, are typically characterized by the intimate coexistence of two phases across a morphotropic phase boundary. Electrically switching one to the other yields large electromechanical coupling coefficients. Driven by global environmental concerns, there is currently a strong push to discover practical lead-free piezoelectrics for device engineering. Using a combination of epitaxial growth techniques in conjunction with theoretical approaches, we show the formation of a morphotropic phase boundary through epitaxial constraint in lead-free piezoelectric bismuth ferrite (BiFeO3) films. Electric field-dependent studies show that a tetragonal-like phase can be reversibly converted into a rhombohedral-like phase, accompanied by measurable displacements of the surface, making this new lead-free system of interest for probe-based data storage and actuator applications.

Nucleosome positioning and gene regulation: advances through genomics

Abstract: Knowing the precise locations of nucleosomes in a genome is key to understanding how genes are regulated. Recent 'next generation' ChIP-chip and ChIP-Seq technologies have accelerated our understanding of the basic principles of chromatin organization. Here we discuss what high-resolution genome-wide maps of nucleosome positions have taught us about how nucleosome positioning demarcates promoter regions and transcriptional start sites, and how the composition and structure of promoter nucleosomes facilitate or inhibit transcription. A detailed picture is starting to emerge of how diverse factors, including underlying DNA sequences and chromatin remodelling complexes, influence nucleosome positioning.

Direct Biological Conversion of Electrical Current into Methane by Electromethanogenesis

Abstract: New sustainable methods are needed to produce renewable energy carriers that can be stored and used for transportation, heating, or chemical production. Here we demonstrate that methane can directly be produced using a biocathode containing methanogens in electrochemical systems (abiotic anode) or microbial electrolysis cells (MECs; biotic anode) by a process called electromethanogenesis. At a set potential of less than −0.7 V (vs Ag/AgCl), carbon dioxide was reduced to methane using a two-chamber electrochemical reactor containing an abiotic anode, a biocathode, and no precious metal catalysts. At −1.0 V, the current capture efficiency was 96%. Electrochemical measurements made using linear sweep voltammetry showed that the biocathode substantially increased current densities compared to a plain carbon cathode where only small amounts of hydrogen gas could be produced. Both increased current densities and very small hydrogen production rates by a plain cathode therefore support a mechanism of methane pro...

On lightweight mobile phone application certification

Abstract: Users have begun downloading an increasingly large number of mobile phone applications in response to advancements in handsets and wireless networks. The increased number of applications results in a greater chance of installing Trojans and similar malware. In this paper, we propose the Kirin security service for Android, which performs lightweight certification of applications to mitigate malware at install time. Kirin certification uses security rules, which are templates designed to conservatively match undesirable properties in security configuration bundled with applications. We use a variant of security requirements engineering techniques to perform an in-depth security analysis of Android to produce a set of rules that match malware characteristics. In a sample of 311 of the most popular applications downloaded from the official Android Market, Kirin and our rules found 5 applications that implement dangerous functionality and therefore should be installed with extreme caution. Upon close inspection, another five applications asserted dangerous rights, but were within the scope of reasonable functional needs. These results indicate that security configuration bundled with Android applications provides practical means of detecting malware.

Initial Construction and Validation of the Pathological Narcissism Inventory

Abstract: The construct of narcissism is inconsistently defined across clinical theory, social-personality psychology, and psychiatric diagnosis. Two problems were identified that impede integration of research and clinical findings regarding narcissistic personality pathology: (a) ambiguity regarding the assessment of pathological narcissism vs. normal narcissism and (b) insufficient scope of existing narcissism measures. Four studies are presented documenting the initial derivation and validation of the Pathological Narcissism Inventory (PNI). The PNI is a 52-item self-report measure assessing 7 dimensions of pathological narcissism spanning problems with narcissistic grandiosity (Entitlement Rage, Exploitativeness, Grandiose Fantasy, Self-sacrificing Self-enhancement) and narcissistic vulnerability (Contingent Self-esteem, Hiding the Self, Devaluing). The PNI structure was validated via confirmatory factor analysis. The PNI correlated negatively with self-esteem and empathy, and positively with shame, interpersonal distress, aggression, and borderline personality organization. Grandiose PNI scales were associated with vindictive, domineering, intrusive, and overly-nurturant interpersonal problems, and vulnerable PNI scales were associated with cold, socially avoidant, and exploitable interpersonal problems. In a small clinical sample, PNI scales exhibited significant associations with parasuicidal behavior, suicide attempts, homicidal ideation, and several aspects of psychotherapy utilization.

High-Rate Solar Photocatalytic Conversion of CO2 and Water Vapor to Hydrocarbon Fuels

Abstract: Efficient solar conversion of carbon dioxide and water vapor to methane and other hydrocarbons is achieved using nitrogen-doped titania nanotube arrays, with a wall thickness low enough to facilitate effective carrier transfer to the adsorbing species, surface-loaded with nanodimensional islands of cocatalysts platinum and/or copper. All experiments are conducted in outdoor sunlight at University Park, PA. Intermediate reaction products, hydrogen and carbon monoxide, are also detected with their relative concentrations underlying hydrocarbon production rates and dependent upon the nature of the cocatalysts on the nanotube array surface. Using outdoor global AM 1.5 sunlight, 100 mW/cm(2), a hydrocarbon production rate of 111 ppm cm(-2) h(-1), or approximately 160 microL/(g h), is obtained when the nanotube array samples are loaded with both Cu and Pt nanoparticles. This rate of CO(2) to hydrocarbon production obtained under outdoor sunlight is at least 20 times higher than previous published reports, which were conducted under laboratory conditions using UV illumination.

How and why people Twitter: the role that micro-blogging plays in informal communication at work

Abstract: Micro-blogs, a relatively new phenomenon, provide a new communication channel for people to broadcast information that they likely would not share otherwise using existing channels (e.g., email, phone, IM, or weblogs). Micro-blogging has become popu-lar quite quickly, raising its potential for serving as a new informal communication medium at work, providing a variety of impacts on collaborative work (e.g., enhancing information sharing, building common ground, and sustaining a feeling of connectedness among colleagues). This exploratory research project is aimed at gaining an in-depth understanding of how and why people use Twitter - a popular micro-blogging tool - and exploring micro-blog's poten-tial impacts on informal communication at work.