Showing papers by "Purdue University published in 1997"

The psychology of attitudes.

Abstract: This is the only truly comprehensive advanced level textbook in the past 20 years designed for courses in the pscyhology of attitudes and related studies in attitude measurement, social cognition. Written by two of the most distinguished scholars in the field, its comprehensive coverage of classic and modern research and theory is unsurpassed.

Toward a stewardship theory of management

Abstract: Recent thinking about top management has been influenced by alternative models of man.1 Economic approaches to governance such as agency theory tend to assume some form of homo-economicus, which depict subordinates as individualistic, opportunistic, and self-serving. Alternatively, sociological and psychological approaches to governance such as stewardship theory depict subordinates as collectivists, pro-organizational, and trustworthy. Through this research, we attempt to reconcile the differences between these assumptions by proposing a model based upon the subordinate's psychological attributes and the organization's situational characteristics.

Electronic Transport in Mesoscopic Systems

Abstract: 1. Preliminary concepts 2. Conductance from transmission 3. Transmission function, S-matrix and Green's functions 4. Quantum Hall effect 5. Localisation and fluctuations 6. Double-barrier tunnelling 7. Optical analogies 8. Non-equilibrium Green's function formalism.

Children with Specific Language Impairment

Abstract: Part 1 Foundations: introduction characterizing the language deficit - basic concepts. Part 2 Describing the data - linguistic and nonlinguistic findings: the language characteristics of SLI - a detailed look at English SLI across languages evidence from nonlinguistic cognitive tasks auditory processing and speech perception. Part 3 Nature and nurture: the genetics and neurobiology of SLI the linguistic and communicative environment. Part 4 Clinical issues: problems of differential diagnosis the nature and efficiency of treatment. Part 5 SLI as a deficit in linguistic knowledge SLI as a limitation in general processing capacity SLI as a processing deficit in specific mechanisms. Part 6 Conclusions: why study SLI revisited.

Media Framing of a Civil Liberties Conflict and Its Effect on Tolerance

Abstract: public controversy. In the present research, we examine how local television news outlets framed a specific, dramatic event: a demonstration and rally by the Ku Klux Klan (KKK) in a small Ohio city. We explore the effect of alternative news frames for this event on tolerance for KKK activities. We also test contrasting hypotheses about how viewers psychologically process news frames, and how such frames ultimately affect viewers' thoughts about political controversies.

Chemistry and uses of pectin--a review.

Abstract: Pectin is an important polysaccharide with applications in foods, Pharmaceuticals, and a number of other industries. Its importance in the food sector lies in its ability to form gel in the presence of Ca2+ ions or a solute at low pH. Although the exact mechanism of gel formation is not clear, significant progress has been made in this direction. Depending on the pectin, coordinate bonding with Ca2+ ions or hydrogen bonding and hydrophobic interactions are involved in gel formation. In low‐methoxyl pectin, gelation results from ionic linkage via calcium bridges between two carboxyl groups belonging to two different chains in close contact with each other. In high‐methoxyl pectin, the cross‐linking of pectin molecules involves a combination of hydrogen bonds and hydrophobic interactions between the molecules. A number of factors—pH, presence of other solutes, molecular size, degree of methoxylation, number and arrangement of side chains, and charge density on the molecule— influence the gelation o...

The Development and Validation of the Children’s Hope Scale

Abstract: Assuming that children are goal-oriented, it is suggested that their thoughts are related to two components--agency and pathways. Agency thoughts reflect the perception that children can initiate and sustain action toward a desired goal; pathways thoughts reflect the children's perceived capability to produce routes to those goals. Hope reflects the combination of agentic and pathways thinking toward goals. A six-item dispositional self-report index called the Children's Hope Scale is introduced and validated for use with children ages 8-16. Results suggest that the scale evidence internal consistency, and is relatively stable over retesting. Additionally, the scale exhibits convergent, discriminant, and incremental validity. Limitations and uses of the scale are discussed.

Commercial bank net interest margins, default risk, interest-rate risk, and off-balance sheet banking

Abstract: This paper tests the hypothesis that banks with more risky loans and higher interest-rate risk exposure would select loan and deposit rates to achieve higher net interest margins. Call Report data for different size classes of banks for 1989–1993 show that the net interest margins of commercial banks reflect both default and interest-rate risk premia. The net interest margins of money-center banks are affected by default risk, but not by interest rate risk, which is consistent with their greater concentration in short-term assets and off-balance sheet (OBS) hedging instruments. By contrast, (super-) regional banking firms are sensitive to interest-rate risk but not to default risk. The data show that OBS activities promote a more diversified, margins-generating asset base than deposit- or equity-financing, and that cross-sectional differences in interest-rate risk and liquidity risk are related to differences in OBS exposure.

Bcl-x(L) forms an ion channel in synthetic lipid membranes.

Abstract: Bcl-2-related proteins are critical regulators of cell survival that are localized to the outer mitochondrial, outer nuclear and endoplasmic reticulum membranes. Despite their physiological importance, the biochemical function of Bcl-2-related proteins has remained elusive. The three-dimensional structure of Bcl-xL, an inhibitor of apoptosis, was recently shown to be similar to the structures of the pore-forming domains of bacterial toxins. A key feature of these pore-forming domains is the ability to form ion channels in biological membranes. Here we demonstrate that Bcl-xL shares this functional feature. Like the bacterial toxins, Bcl-xL can insert into either synthetic lipid vesicles or planar lipid bilayers and form an ion-conducting channel. This channel is pH-sensitive and becomes cation-selective at physiological pH. The ion-conducting channel(s) formed by Bcl-xL display multiple conductance states that have identical ion selectivity. Together, these data suggest that Bcl-xL may maintain cell survival by regulating the permeability of the intracellular membranes to which it is distributed.

Rings, Modules, and Algebras in Stable Homotopy Theory

Abstract: Introduction Prologue: the category of ${\mathbb L}$-spectra Structured ring and module spectra The homotopy theory of $R$-modules The algebraic theory of $R$-modules $R$-ring spectra and the specialization to $MU$ Algebraic $K$-theory of $S$-algebras $R$-algebras and topological model categories Bousfield localizations of $R$-modules and algebras Topological Hochschild homology and cohomology Some basic constructions on spectra Spaces of linear isometries and technical theorems The monadic bar construction Epilogue: The category of ${\mathbb L}$-spectra under $S$ Appendix A. Twisted half-smash products and function spectra Bibliography Index.

Social Origins of Self-Regulatory Competence

Abstract: This article reviews the social origins of students' development of self-regulatory skill with special emphasis on observational learning through modeling A social cognitive perspective on self-regulation is presented In this view, students' academic competence develops initially from social sources of academic skill and subsequently shifts to self sources in a series of 4 levels: observational, imitative, self-controlled, and self-regulated The effects of models on observers depend in part on perceptions of self-efficacy, or beliefs about one's capabilities to learn or perform designated behaviors Research on social influences is reviewed, and includes factors such as cognitive modeling, coping and mastery models, self-modeling, learning goals, and progress feedback Related theoretical perspectives are discussed along with suggestions for future research

Reliable multicast transport protocol (RMTP)

Abstract: This paper presents the design, implementation, and performance of a reliable multicast transport protocol (RMTP). The RMTP is based on a hierarchical structure in which receivers are grouped into local regions or domains and in each domain there is a special receiver called a designated receiver (DR) which is responsible for sending acknowledgments periodically to the sender, for processing acknowledgment from receivers in its domain, and for retransmitting lost packets to the corresponding receivers. Since lost packets are recovered by local retransmissions as opposed to retransmissions from the original sender, end-to-end latency is significantly reduced, and the overall throughput is improved as well. Also, since only the DRs send their acknowledgments to the sender, instead of all receivers sending their acknowledgments to the sender, a single acknowledgment is generated per local region, and this prevents acknowledgment implosion. Receivers in RMTP send their acknowledgments to the DRs periodically, thereby simplifying error recovery. In addition, lost packets are recovered by selective repeat retransmissions, leading to improved throughput at the cost of minimal additional buffering at the receivers. This paper also describes the implementation of RMTP and its performance on the Internet.

Low Cost Attacks on Tamper Resistant Devices

Abstract: There has been considerable recent interest in the level of tamper resistance that can be provided by low cost devices such as smart-cards. It is known that such devices can be reverse engineered using chip testing equipment, but a state of the art semiconductor laboratory costs millions of dollars. In this paper, we describe a number of attacks that can be mounted by opponents with much shallower pockets.

Current-Voltage Characteristics of Self-Assembled Monolayers by Scanning Tunneling Microscopy

Abstract: This paper presents a comparison of the theoretical and experimental current-voltage (I-V) characteristics of a self-assembled monolayer of $\ensuremath{\alpha},{\ensuremath{\alpha}}^{\ensuremath{'}}\ensuremath{-}\mathrm{x}\mathrm{y}\mathrm{l}\mathrm{y}\mathrm{l}$ dithiol molecules on a gold substrate measured with a scanning tunneling microscope probe. Good quantitative agreement is obtained with the tip-molecule distance as the only ``fitting parameter.'' Several other thiol-coupled molecules that we have studied also show similar agreement. The conceptual picture presented in this paper could be useful for the interpretation of I-V measurements on molecular monolayers in general.

The size distribution of droplets in the exhaled breath of healthy human subjects.

Abstract: Droplets carried in exhaled breath may carry microorganisms capable of transmitting disease over both short and long distances. The size distribution of such droplets will influence the type of organisms that may be carried as well as strategies for controlling airborne infection. The aim of this study was to characterize the size distribution of droplets exhaled by healthy individuals. Exhaled droplets from human subjects performing four respiratory actions (mouth breathing, nose breathing, coughing, talking) were measured by both an optical particle counter (OPC) and an analytical transmission electron microscope (AEM). The OPC indicated a preponderance of particles less than 1 mu, although larger particles were also found. Measurements with the AEM confirmed the existence of larger sized droplets in the exhaled breath. In general, coughing produced the largest droplet concentrations and nose breathing the least, although considerable intersubject variability was observed.

Identification of extractable growth factors from small intestinal submucosa.

Abstract: When implanted as a biomaterial for tissue replacement, selected submucosal layers of porcine small intestine induce site-specific tissue remodeling. Small intestinal submucosa (SIS), as isolated, is primarily an acellular extracellular matrix mater~al. In an attempt to discover the components of small intestinal submucosa which are able to induce this tissue remodeling, the material was extracted and extracts were tested for the ability to stimulate Swiss 3T3 fibroblasts to synthesize DNA and proliferate. Each oi the iour different extracts of small intestinal submucosa had measurablecell-stimulating activity when analyzed in both a whole cell proliferation assay (alamarBlue dye reduction) and a DNA synthesis assay (('HI-thymidine incorporation). Proteins extracted from SIS with 2 M urea induced activity profiles in the two assays which were very similar to the activity profiles of basic fibroblast growth factor (FGF-2) in the assays. As well, the changes in cell morphology in response to the extracted proteins mimicked the changes induced by FGF-2. Neutralization experiments with specific antibodies to this growth factor confirmed the presence of FGF-2 and indicated that it was responsible for 60% oi the fibroblast-stimulating activity of the urea extract oi small intestinal submucosa. Western blot analvsis with a monoclonal antibody specific for FGF-2 detected a reactive doublet at approximately 19 kDa and further confirmed the presence oi FGF-2. Cell stimulat~ng activity oi proteins extracted irom SIS with 4 M guanidine was neutralized by an antibody specific ior transforming growth factor P CTCFB). Changes in the morphology oi the fibroblasts exposed to this extract were nearly identical to changes induced by TGFB. Although no reactive protein band was detected at 25 kDa in nonreduced western blot analysis, several bands were reactive at higher molecular weight. The identity of this TGFf3-related component of small intestinal submucosa is unknown. Identification of FGF-2 and TGFp-related activities in SIS, two growth tactors known to significantly affect critical processes oi tissue development and difierentiation, provides the opportunity to further elucidate the mechanisms by which this extracellu- larmatrix biomaterial modulates wound healing and tissueremodeling. J. Cell. Biochem. 67:478491,1997. Q 1997wik+~. ~nc

Analysis of a denial of service attack on TCP

Abstract: The paper analyzes a network based denial of service attack for IP (Internet Protocol) based networks. It is popularly called SYN flooding. It works by an attacker sending many TCP (Transmission Control Protocol) connection requests with spoofed source addresses to a victim's machine. Each request causes the targeted host to instantiate data structures out of a limited pool of resources. Once the target host's resources are exhausted, no more incoming TCP connections can be established, thus denying further legitimate access. The paper contributes a detailed analysis of the SYN flooding attack and a discussion of existing and proposed countermeasures. Furthermore, we introduce a new solution approach, explain its design, and evaluate its performance. Our approach offers protection against SYN flooding for all hosts connected to the same local area network, independent of their operating system or networking stack implementation. It is highly portable, configurable, extensible, and requires neither special hardware, nor modifications in routers or protected end systems.

Elementary scattering theory of the Si MOSFET

Abstract: A simple one-flux scattering theory of the silicon MOSFET is introduced. Current-voltage (I-V) characteristics are expressed in terms of scattering parameters rather than a mobility. For long-channel transistors, the results reduce to conventional drift-diffusion theory, but they also apply to devices in which the channel length is comparable to or even shorter than the mean-free-path. The results indicate that for very short channels the transconductance is limited by carrier injection from the source. The theory also indicates that evaluation of the drain current in short-channel MOSFETs is a near-equilibrium transport problem, even though the channel electric field is large in magnitude and varies rapidly in space.

Casting Antimicrobial Packaging Films and Measuring Their Physical Properties and Antimicrobial Activity

Abstract: Antimicrobial film was extruded using LDPE resins and potassium sorbate powder; its tensile properties, transparency and antimicrobial activity were measured to examine the adaptability as a packaging material. The tensile properties were not affected significantly by the incorporation of potassium sorbate to 3% (w/w) in the film. However, transparency of the film decreased as the concentration of potassium sorbate increased. The antimicrobial film decreased the growth rate and maximum growth of yeast, and extended the lag period before mold growth was apparent. Therefore, it can prevent or reduce the rate of microbial spoilage in low viscosity liquids and on the contacted surface area of solid food products and thus may prolong the shelf life of food products when it is used as a packaging material.

Quantifying urban forest structure, function, and value: the Chicago Urban Forest Climate Project

Abstract: This paper is a review of research in Chicago that linked analyses of vegetation structure with forest functions and values. During 1991, the regions trees removed an estimated 5575 metric tons of air pollutants, providing air cleansing worth 9.2 million. Each year they sequester an estimated 315 800 metric tons of carbon. Increasing tree cover 10% or planting about three trees per building lot saves annual heating and cooling costs by an estimated 50 to 90 per dwelling unit because of increased shade, lower summertime air temperatures, and reduced neighborhood wind speeds once the trees mature. The net present value of the services trees provide is estimated as 402 per planted tree. The present value of long-term benefits is more than twice the present value of costs.

New Pedagogy and New Content: The Case of Statistics

Abstract: Summary Statistical education now takes place in a new social context. It is influenced by a movement to reform the teaching of the mathematical sciences in general. At the same time, the changing nature of our discipline demands revised content for introductory instruction, and technology strongly influences both what we teach and how we teach. The case for substantial change in statistics instruction is built on strong synergies between content, pedagogy, and technology. Statisticians who teach beginners should become more familiar with research on teaching and learning and with changes in educational technology. The spirit of contemporary introductions to statistics should be very different from the traditional emphasis on lectures and on probability and inference.

Quick Response in Manufacturer-Retailer Channels

Abstract: Quick Response QR is a movement in the apparel industry to shorten lead time. Under QR, the retailer has the ability to adjust orders based on better demand information. We study how a manufacturer-retailer channel impacts choices of production and marketing variables under QR in the apparel industry. Specifically, we build formal models of the inventory decisions of manufacturers and retailers both before and after QR. Our models allow us to address who wins and who loses under QR, and suggest actions such as service level, wholesale price and volume commitments that can be used to make QR profitable for both members of the channel, i.e., Pareto improving. Detailed discussions with a major retailer, and information from industry sources provide supporting evidence for the structure and conclusions of the model.

Modern Compiler Implementation in Java

Abstract: From the Publisher: The first part of the book, Fundamentals of Compilation, is suitable for a one-semester first course in compiler design. The second part, Advanced Topics, which includes the compilation of object-oriented and functional languages, garbage collection, loop optimization, SSA form, instruction scheduling, optimization for cache-memory hierarchies, can be used for a second-semester or graduate course.

Method and apparatus using vagal stimulation for control of ventricular rate during atrial fibrillation

Abstract: A closed-loop variable frequency vagal stimulation apparatus for control of ventricular rate during atrial fibrillation. In one embodiment the apparatus includes a stimulator applied to the left vagus nerve and a proportional controller programmed to automatically and continuously adjust the vagal stimulation frequency proportionally as a function of the difference between actual and desired ventricular excitation rates. In a second embodiment the apparatus includes a vagal nerve stimulator and a controller which automatically adjusts the vagal stimulation frequency as a function of the difference between ventricular excitation rate and arterial pulse rate in order to eliminate or minimize pulse deficit.

The Pto kinase conferring resistance to tomato bacterial speck disease interacts with proteins that bind a cis-element of pathogenesis-related genes

Abstract: In tomato, the Pto kinase confers resistance to bacterial speck disease by recognizing the expression of a corresponding avirulence gene, avrPto, in the pathogen Pseudomonas syringae pv. tomato. Using the yeast two-hybrid system, we have identified three genes, Pti4, Pti5 and Pti6, that encode proteins that physically interact with the Pto kinase. Pti4/5/6 each encode a protein with characteristics that are typical of transcription factors and are similar to the tobacco ethylene-responsive element-binding proteins (EREBPs). Using a gel mobility-shift assay, we demonstrate that, similarly to EREBPs, Pti4/5/6 specifically recognize and bind to a DNA sequence that is present in the promoter region of a large number of genes encoding ‘pathogenesis-related’ (PR) proteins. Expression of several PR genes and a tobacco EREBP gene is specifically enhanced upon Pto–avrPto recognition in tobacco. These observations establish a direct connection between a disease resistance gene and the specific activation of plant defense genes.