Insiders Behaving Badly

This column goes beyond previous insider analyses to identify a framework for a taxonomy of insider threats including both malicious and inadvertent actions by insiders that put organizations or their resources at some risk. The framework includes factors reflecting the organization, the individual, the information technology system, and the environment.     

The moderating impact of sex on the equity–satisfaction relationship: A field study.

Explored whether males' satisfaction with an exchange relationship is more dependent on the equity of that relationship, relative to females'. 26 male and 25 female members of 1 of 3 business lead and referral clubs (1 all female, 1 primarily male, and 1 approximately equal in males and females) rated their own and others' inputs and outcomes into the exchange relationship, as well as their satisfaction with the relationship. Results indicate that satisfaction was lower in a negatively inequitable than equitable relationship and slightly lower in an equitable than positively inequitable relationship. As predicted, the relationship of equity and satisfaction was considerably more pronounced for male than female club members. Further analyses revealed that the equity-satisfaction relationship was especially (a) pronounced for males in the primarily male group and (b) weak for females in an all-female group. The latter findings suggest that the salience of the equity norm may be a joint function of the sex of both members of an exchange relationship. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

External and internal electrostatic potentials of cholinesterase models

The electrostatic potentials for the three-dimensional structures of cholinesterases from various species were calculated, using the Delphi algorithm, on the basis of the Poisson–Boltzmann equation. We used structures for Torpedo californica and mouse acetylcholinesterase, and built homology models of the human, Bungarus fasciatus, and Drosophila melanogaster acetylcholinesterases and human butyrylcholinesterase. All these structures reveal a negative external surface potential, in the area around the entrance to the active-site gorge, that becomes more negative as the rim of the gorge is approached. Moreover, in all cases, the potential becomes increasingly more negative along the central axis running down the gorge, and is largest at the base of the gorge, near the active site. Ten key acidic residues conserved in the sequence alignments of AChE from various species, both in the surface area near the entrance of the active-site gorge and at its base, appear to be primarily responsible for these potentials. The potentials are highly correlated among the structures examined, down to sequence identities as low as 35%. This indicates that they are a conserved property of the cholinesterase family, could serve to attract the positively charged substrate into and down the gorge to the active site, and may play other roles important for cholinesterase function.     

Networks for sorting multitonic sequences

Lee and Batcher have designed networks that efficiently merge k separately provided sorted sequences of known lengths totalling n. We show that the design is still possible, and in fact easier to describe, if we do not make use of the lengths, or even the directions of monotonicity, of the individual sequences—the sequences can be provided in a single undelimited concatenation of length n. The depth of the simplest resulting network to sort sequences that are “k-tonic” and of length n is , generalizing Batcher's 1968 results for the extreme values of k (k=2 corresponding to merging, and k=n/2 corresponding to general sorting).The exposition is self-contained and can serve even as an introduction to sorting networks and Batcher's results.     

New bounds on the number of frictionless fingers requied to immobilize

Using a novel second-order mobility theory that was recently developed by the authors, this article develops new lower bounds on the number of frictionless fingers required to immobilize generic planar objects. We show that any generic smooth or polygonal planar object can be immobilized with three convex fingers or fixtures that have sufficiently flat curvature. Further, if it is possible to specify the fingertip curvature, then any generic smooth or polygonal object can be immobilized with two, possibly concave, fingers. © 1995 John Wiley & Sons, Inc.     

Percutaneous Absorption Enhancement by Nonionic Surfactants

The influence of nonionic surfactants (polysorbates) on hydrocortisone penetration through hairless mouse skin in vitro has been determined. Permeation was quite slow from purely aqueous media containing surfactants following finite dose application. However, if the vehicle contained high propylene glycol concentrations (40% or more), inclusion of a surfactant increased permeation rate significantly. Similar effects were noted following application of a large donor volume (infinite dose). Synergism was attributed to enhancement of surfactant absorption by the stratum corneum leading to changes in skin barrier resistance. With vehicles containing a surfactant, penetration was higher after finite dose application due to compositional changes within the vehicle.     

Interactive quadrangulation with Reeb atlases and connectivity textures

Creating high-quality quad meshes from triangulated surfaces is a highly nontrivial task that necessitates consideration of various application specific metrics of quality. In our work, we follow the premise that automatic reconstruction techniques may not generate outputs meeting all the subjective quality expectations of the user. Instead, we put the user at the center of the process by providing a flexible, interactive approach to quadrangulation design. By combining scalar field topology and combinatorial connectivity techniques, we present a new framework, following a coarse to fine design philosophy, which allows for explicit control of the subjective quality criteria on the output quad mesh, at interactive rates. Our quadrangulation framework uses the new notion of Reeb atlas editing, to define with a small amount of interactions a coarse quadrangulation of the model, capturing the main features of the shape, with user prescribed extraordinary vertices and alignment. Fine grain tuning is easily achieved with the notion of connectivity texturing, which allows for additional extraordinary vertices specification and explicit feature alignment, to capture the high-frequency geometries. Experiments demonstrate the interactivity and flexibility of our approach, as well as its ability to generate quad meshes of arbitrary resolution with high-quality statistics, while meeting the user’s own subjective requirements.     

Injection molding shrinkage of PP: Experimental progress

Injection molding shrinkage deals with dimensional differences between a molded part and the cavity. By adding an array of orthogonal marks into a mold, local shrinkage values may be obtained by comparing dimensions of this array with dimensions of the array replicated on the surface of the parts. A profilograph is employed to obtain dimensional measurements, in the parallel to flow direction and in the cross flow direction. A sensitivity analysis is conducted to determine aspects of shrinkage evaluation causing uncertainty on the results. Prominent sources of uncertainty found are mark straightness defect and part warpage. Uncertainty on shrinkage is evaluated to 0.00025 mm/mm for a distance between the marks of 6.350 mm. Shrinkages have been evaluated locally for molded plates. Different distribution forms were observed for parallel to flow and cross flow shrinkage. Important anisotropy is also observed. The effects of holding pressure and injection velocity on shrinkages have been evaluated using a 2³ factorial design of experiment for three locations on the plates. Finally, shrinkages for three mold geometries have been compared: constant thickness plate, variable in thickness symmetrical plate, and variable in thickness asymmetrical plate. Variable in thickness plates showed the importance of solidification dynamics on final shrinkages. POLYM. ENG. SCI., 46:1275–1283, 2006. © 2006 Society of Plastics Engineers     

A review of the unique features of HDL apoproteins

The human plasma high density lipoproteins (HDL) are a heterogeneous ensemble of five proteins associated with both neutral and polar lipids. The sequences of all five proteins are known. ApoA-I and apoA-II are the major protein components; apoC-I, apoC-II and apoC-III are the minor protein components. All these apoproteins spontaneously recombine with phospholipids to give stable lipid-protein complexes and freely exchange between the two major HDL subclasses, HDL₂ and HDL₃. In addition, ApoC-I, apoC-II, and apoC-III exchange between HDL and very low density lipoproteins. Furthermore, certain HDL apoproteins are activators for plasma enzymes that are important in lipid metabolism. ApoA-I and apoC-I activate lecithin/cholesterol acyltransferase; apoC-II is an activator of lipoprotein lipase. The regions of apoC-I and apoC-II that are involved in the activation of these enzymes have been localized with synthetic peptides. Studies of synthetic and native fragments of apoA-II, apoC-I, apoC-II, and apoC-III as well as model lipid-binding peptides have identified specific regions with structural features common to lipid-binding proteins. These special properties, which include helical potential, sequences with a critical amphipathic length, and high hydrophobicity of the nonpolar side of the amphipathic helix, are the determinants of HDL structure and metabolism.     

Approximate similarity search for online multimedia services on distributed CPU–GPU platforms

Similarity search in high-dimensional spaces is a pivotal operation for several database applications, including online content-based multimedia services. With the increasing popularity of multimedia applications, these services are facing new challenges regarding (1) the very large and growing volumes of data to be indexed/searched and (2) the necessity of reducing the response times as observed by end-users. In addition, the nature of the interactions between users and online services creates fluctuating query request rates throughout execution, which requires a similarity search engine to adapt to better use the computation platform and minimize response times. In this work, we address these challenges with Hypercurves, a flexible framework for answering approximate k-nearest neighbor (kNN) queries for very large multimedia databases. Hypercurves executes in hybrid CPU–GPU environments and is able to attain massive query-processing rates through the cooperative use of these devices. Hypercurves also changes its CPU–GPU task partitioning dynamically according to the observed load, aiming for optimal response times. In our empirical evaluation, dynamic task partitioning reduced query response times by approximately 50 % compared to the best static task partition. Due to a probabilistic proof of equivalence to the sequential kNN algorithm, the CPU–GPU execution of Hypercurves in distributed (multi-node) environments can be aggressively optimized, attaining superlinear scalability while still guaranteeing, with high probability, results at least as good as those from the sequential algorithm.