The Quality of Open Source Production: Zealots and Good Samaritans in the Case of Wikipedia

New forms of production based in electronic technology, such as open-source and open-content production, convert private commodities (typically software) into essentially public goods. A number of studies find that, like in other collective goods, incentives for reputation and group identity motivate contributions to open source goods, thereby overcoming the social dilemma inherent in producing such goods. In this paper we examine how contributor motivations affect the quality of contributions to the open-content online encyclopedia Wikipedia. We find that quality is associated with contributor motivations, but in a surprisingly inconsistent way. Registered users\u27 quality increases with more contributions, consistent with the idea of participants motivated by reputation and commitment to the Wikipedia community. Surprisingly, however, we find the highest quality from the vast numbers of anonymous Good Samaritans who contribute only once. Our findings that Good Samaritans as well as committed zealots contribute high quality content to Wikipedia suggest that it is the quantity as well as the quality of contributors that positively affects the quality of open source production

Proposal for a low cost close air support aircraft for the year 2000: The Raptor

The Raptor is a proposed low cost Close Air Support (CAS) aircraft for the U.S. Military. The Raptor incorporates a 'cranked arrow' wing planform, and uses canards instead of a traditional horizontal tail. The Raptor is designed to be capable of responsive delivery of effective ordnance in close proximity to friendly ground forces during the day, night, and 'under the weather' conditions. Details are presented of the Raptor's mission, configuration, performance, stability and control, ground support, manufacturing, and overall cost to permit engineering evaluation of the proposed design. A description of the design process and analysis methods used is also provided

Beneath the beard : do facial morphometrics influence the strength of judgments of men's beardedness?

This study was supported by a University of Queensland Postdoctoral Research Fellowship awarded to BJWD.Converging evidence suggests men's beards, like many androgen-dependent masculine secondary sexual traits, communicate masculinity and dominance intra-sexually while effects of men's beardedness on attractiveness ratings are more equivocal. Beards may enhance perceived masculinity and dominance via amplifying aspects of underlying craniofacial masculinity, particularly the size of the lower face and jaw. Here we tested these predictions across two studies. In Study 1, we tested how three facial metrics - objectively measured craniofacial masculinity, facial-width-to-height ratio (fWHR), and jaw size - calculated while clean-shaven impacted on ratings of attractiveness, masculinity and dominance of 37 men photographed when clean-shaven and with full beards. Results showed that beards exerted significant and positive effects on masculinity, dominance and to a lesser extent attractiveness. However, fWHR did not significantly interact with beardedness to influence the directions of any of the ratings, and while some linear and nonlinear interactions were significant between objective craniofacial masculinity and beardedness as well as between jaw size and beardedness, they tended to be subtle and dwarfed by the large main effect of beardedness on perceptual ratings. In Study 2, we measured ratings of attractiveness, masculinity and dominance for composite clean-shaven and bearded stimuli experimentally manipulated in facial shape to represent ±50% the shape of a beard, essentially manipulating the size of the lower face and jaw of the stimuli. We found a strong main effect whereby bearded stimuli enhanced dominance and masculinity ratings over clean-shaven stimuli. Increasing the size of the lower face and jaw augmented ratings of masculinity and dominance in clean-shaven stimuli but did not exert strong effects within bearded stimuli. Attractiveness ratings were highest for bearded faces with smaller jaws followed by bearded and clean-shaven faces with larger jaws and lowest for clean-shaven faces with small jaws. Taken together, our findings suggest that beards exert main effects on masculinity and dominance possibly by amplifying male typical facial shape. Attractiveness ratings of facial hair may reflect a compromise between overly dominant looking faces with larger jaws and the additive effects beardedness has on these ratings.PostprintPeer reviewe

Overview of Game and Content Design for a Mobile Game that Will Prepare Students in Calculus and Physics Prerequisites to the Engineering Curriculum

As part of a research project which assists veterans as they exit the military, complete engineering degrees, and enter the workforce as engineering professionals, a range of serious games for Science, Technology, Engineering, and Mathematics (STEM) education is under development. The current focus of this development is CAPTIVATE, a serious game to assist student veterans in mastering the calculus and physics skills that are necessary prerequisites to the main engineering curriculum. Building on the development and lessons learned from MAVEN, a game developed previously to help student veterans master precalculus skills, the design and initial implementation for CAPTIVATE involves careful consideration regarding game and instructional design. Many of the positive aspects from the design of MAVEN will be implemented in CAPTIVATE. First, the overall framework developed for MAVEN will be reused in CAPTIVATE. This modular framework involves both a model and process that combine game, instructional, and software design in a way that supports adaptability throughout the design and development cycle. Additionally by embedding concepts in game play similar to well-known board games such as Battleship, computer games such as Minesweeper, and console or mobile games such as Guitar Hero, students will use their calculus and physics skills to complete tasks in a familiar environment. In addition, the game itself will consist of a series of sub-games each focusing on a topic that students traditionally struggle to understand. Furthermore, students will be offered access to learning resources and assessed regularly as they progress through the game. CAPTIVATE will also overcome some shortcomings from the previous development. While MAVEN was developed for desktop deployment, CAPTIVATE is targeted for deployment on a variety of mobile device including Apple and Android phones and tablets to engage students in interactive games that support their endeavor to build a solid foundation in mathematics and science topics. Additionally by creating games that are short and easily accessible, students will be able to engage with the material at a time and place convenient for them. The development of CAPTIVATE supports student veterans as they transition from the military to engineering degree programs and helps to accelerate them through their STEM prerequisite courses

Measurement of Position Acuity in Strabismus and Amblyopia: Specificity of the Vernier VEP Paradigm

PURPOSE. An objective measure of positional acuity is desirable in the nonverbal clinical population. This study was conducted to investigate the specificity of the vernier VEP as a measure of positional acuity, evaluating the potential confound of asymmetric motion responses that may be present in some groups of patients. These motion responses could masquerade as position-specific responses, since they occur at the same response frequency as the vernier-related response. METHODS. Twelve observers with early-onset esotropia (EOE), 30 children with untreated amblyopia, and 15 control children underwent swept vernier VEP acuity testing accompanied by a swept motion control stimulus. The control condition was used to detect the presence of artifactual responses not related to position sensitivity. The patients with EOE were selected for high levels of motion asymmetry as documented with oscillating gratings presented monocularly. As a measure of motion confound (penetration), the proportion of first-harmonic responses recorded in the control condition was determined. RESULTS. The penetration rate in the vernier condition in each study group (EOE: 0.93%; amblyopes: 4.26%; normal subjects: 2.40%) and the entire group (2.85%) was acceptably low. The level of penetration was not significantly influenced by the presence of amblyopia. CONCLUSIONS. The vernier VEP paradigm, when applied in the manner described, can be interpreted as a measure of position sensitivity. The presence of motion asymmetry or untreated amblyopia does not affect the validity of vernier measurements made. (Invest Ophthalmol Vis Sci. 2005;46:4563-4570) DOI: 10.1167/iovs.05-0792 I t is well-known, on the one hand, that grating acuity systematically underestimates optotype acuity losses in amblyopia. 1-7 On the other hand, losses on vernier acuity more closely match the loss of optotype acuity than do losses on grating acuity. Visual evoked potentials (VEPs) provide another means of assessing visual function in nonverbal subjects. VEPs specific to vernier offsets have been measured in several studies. The steady state vernier VEP 26 -29 involves the periodic introduction and withdrawal of vernier offsets in a high-contrast square-wave grating target 26 A difficulty in applying the steady state vernier VEP in clinical populations is the possible presence of motion responses that are not symmetric. A clear example of asymmetric motion VEP responses occurs in patients with early-onset esotropia (EOE) in which the monocular response to rapidly oscillating gratings is dominated by odd-harmonic components that reflect the asymmetry of motion processing. 30 -35 A similar asymmetry is found in the monocular response of normal infants. This evidence suggests that a horizontally oriented carrier grating with vertically introduced vernier offsets offers a better choice of stimulus design. In this study, we examine the levels of motion contamination and confound of the steady state vernier VEP by recordings of patients with early-onset esotropia who first had a high level of motion asymmetry docuFrom th

A Glass Polyalkenoate Cement Carrier for Bone Morphogenetic Proteins

This work considers a glass polyalkenoate cement (GPC)-based carrier for the effective delivery of bone morphogenetic proteins (BMPs) at an implantation site. A 0.12 CaO–0.04 SrO–0.36 ZnO–0.48 SiO2 based glass and poly(acrylic acid) (PAA, Mw 213,000) were employed for the fabrication of the GPC. The media used for the water source in the GPC reaction was altered to produce a series of GPCs. The GPC liquid media was either 100 % distilled water with additions of albumin at 0, 2, 5 and 8 wt% of the glass content, 100 % formulation buffer (IFB), and 100 % BMP (150 µg rhBMP-2/ml IFB). Rheological properties, compressive strength, ion release profiles and BMP release were evaluated. Working times (Tw) of the formulated GPCs significantly increased with the addition of 2 % albumin and remained constant with further increases in albumin content or IFB solutions. Setting time (Ts) experienced an increase with 2 and 5 % albumin content, but a decrease with 8 % albumin. Changing the liquid source to IFB containing 5 % albumin had no significant effect on Ts compared to the 8 % albumin-containing BT101. Replacing the albumin with IFB/BMP-2 did not significantly affect Tw. However, Ts increased for the BT101_BMP-2 containing GPCs, compared to all other samples. The compressive strength evaluated 1 day post cement mixing was not affected significantly by the incorporation of BMPs, but the ion release did increase from the cements, particularly for Zn and Sr. The GPCs released BMP after the first day, which decreased in content during the following 6 days. This study has proven that BMPs can be immobilized into GPCs and may result in novel materials for clinical applications

Coupling electron capture dissociation and the modified Kendrick mass defect for sequencing of a poly(2-ethyl-2-oxazoline) polymer

With increasing focus on the structural elucidation of polymers, advanced tandem mass spectrometry techniques will play a crucial role in the characterization of these compounds. In this contribution, synthesis and analysis of methyl initiated and xan-thate terminated poly (2-ethyl-2-oxazoline) using Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry was achieved. Electron capture dissociation (ECD) produced full end group characterization as well as back bone fragmentation including complete sequence coverage of the polymer. A method of fragment ion characterization is also presented with the use of the high resolution modified Kendrick mass defect plots as a means of grouping fragments from the same fragmentation pathways together. This type of data processing is applicable to all tandem mass spectrometry techniques for polymer analysis but is made more effective with high mass accuracy methods. ECD FT-ICR MS demonstrates its promising role as a structural characterization technique for polyoxazoline species

Geodetic Strain Analysis Tool

A geodetic software analysis tool enables the user to analyze 2D crustal strain from geodetic ground motion, and create models of crustal deformation using a graphical interface. Users can use any geodetic measurements of ground motion and derive the 2D crustal strain interactively. This software also provides a forward-modeling tool that calculates a geodetic velocity and strain field for a given fault model, and lets the user compare the modeled strain field with the strain field obtained from the user s data. Users may change parameters on-the-fly and obtain a real-time recalculation of the resulting strain field. Four data products are computed: maximum shear, dilatation, shear angle, and principal components. The current view and data dependencies are processed first. The remaining data products and views are then computed in a round-robin fashion to anticipate view changes. When an analysis or display parameter is changed, the affected data products and views are invalidated and progressively re-displayed as available. This software is designed to facilitate the derivation of the strain fields from the GPS and strain meter data that sample it to facilitate the understanding of the strengths and weaknesses of the strain field derivation from continuous GPS (CGPS) and other geodetic data from a variety of tectonic settings, to converge on the "best practices" strain derivation strategy for the Solid Earth Science ESDR System (SESES) project given the CGPS station distribution in the western U.S., and to provide SESES users with a scientific and educational tool to explore the strain field on their own with user-defined parameters

Topological Constraint Theory Analysis of Rigidity Transition in Highly Coordinate Amorphous Hydrogenated Boron Carbide

Topological constraint theory (TCT) has revealed itself to be a powerful tool in interpreting the behaviors of amorphous solids. The theory predicts a transition between a “rigid” overconstrained network and a “floppy” underconstrained network as a function of connectivity or average coordination number, 〈r〉. The predicted results have been shown experimentally for various glassy materials, the majority of these being based on 4-fold-coordinate networks such as chalcogenide and oxide glasses. Here, we demonstrate the broader applicability of topological constraint theory to uniquely coordinated amorphous hydrogenated boron carbide (a-BC:H), based on 6-fold-coordinate boron atoms arranged into partially hydrogenated interconnected 12-vertex icosahedra. We have produced a substantial set of plasma-enhanced chemical vapor deposited a-BC:H films with a large range of densities and network coordination, and demonstrate a clear threshold in Young\u27s modulus as a function of 〈r〉, ascribed to a rigidity transition. We investigate constraint counting strategies in this material and show that by treating icosahedra as “superatoms,” a rigidity transition is observed within the range of the theoretically predicted 〈r〉c value of 2.4 for covalent solids with bond-stretching and bond-bending forces. This experimental data set for a-BC:H is unique in that it represents a uniform change in connectivity with 〈r〉 and demonstrates a distinct rigidity transition with data points both above and below the transition threshold. Finally, we discuss how TCT can be applied to explain and optimize mechanical and dielectric properties in a-BC:H and related materials in the context of microelectronics applications

Securing Information Technology in Healthcare

Information technology (IT) has great potential to improve healthcare quality while also improving efficiency, and thus has been a major focus of recent healthcare reform efforts. However, developing, deploying and using IT that is both secure and genuinely effective in the complex clinical, organizational and economic environment of healthcare is a significant challenge. Further, it is imperative that we better understand the privacy concerns of patients and providers, as well as the ability of current technologies, policies, and laws to adequately protect privacy. The Securing Information Technology in Healthcare (SITH) workshops were created to provide a forum to discuss security and privacy for experts from a broad range of perspectives, from officers at large healthcare companies, startups and nonprofits, to physicians, researchers and policy makers