The effect of thermal diffusion on the formation of interface resistance on oxide-coated cathodes.

Thesis (M.A.)--Boston UniversityThe goal of this investigation is to determine many of the factors which contribute to cathode interface resistance formation in a commercial type twin triode and to analyze these factors quantitatively by well known chemical and physical methods, However, since the vacuum tube represents such a complex system it is necessary to introduce this problem by reference to early history and many of the parameters associated with vacuum tube manufacture. With reference to historical introduction, the electron theory of metals, with special emphasis on the role which work function plays, is discussed. [TRUNCATED

Late-time Structure of the Bunch-Davies De Sitter Wavefunction

We examine the late time behavior of the Bunch-Davies wavefunction for interacting light fields in a de Sitter background. We use perturbative techniques developed in the framework of AdS/CFT, and analytically continue to compute tree and loop level contributions to the Bunch-Davies wavefunction. We consider self-interacting scalars of general mass, but focus especially on the massless and conformally coupled cases. We show that certain contributions grow logarithmically in conformal time both at tree and loop level. We also consider gauge fields and gravitons. The four-dimensional Fefferman-Graham expansion of classical asymptotically de Sitter solutions is used to show that the wavefunction contains no logarithmic growth in the pure graviton sector at tree level. Finally, assuming a holographic relation between the wavefunction and the partition function of a conformal field theory, we interpret the logarithmic growths in the language of conformal field theory.Comment: 41 pages, 1 figure, minor typos fixed, journal references adde

Desperately Seeking IS Curriculum Relevance: Teaching Information Systems in a Cross-Functional Context

The information systems academic community has been searching for an effective response to the steep decline in enrollment in IS programs. Researchers have identified the design of the introductory IS course as a critical opportunity for increasing student interest in the IS field. In this paper we describe our experience redesigning an introductory IS course in the context of a semester long cross-functional product development project for college juniors. By including practitioners in the design process, we identified four areas to be addressed to increase the career relevance of the course and used this agenda to develop new content which tied the IS course more closely to the semester project, especially in the area of online marketing

Web Services: Enabling Dynamic Business Networks

A Dynamic Business Network is a distinct system of participants (customers, suppliers, complimentors, competitors, service providers) that use the network to achieve customer satisfaction and profitability and where participants and relationships evolve over time. However, unpredictability and rapid change in a Dynamic Business Network creates a significant challenge in implementing and supporting business application software. Traditional information systems implementation methods require an a priori design and are built for a particular purpose for use over an extended period of time. Loosely coupled business networks change interrelationships between nodes both quickly and frequently, thus providing little or no notice for planning, implementing, or changing the supporting applications. The dynamic sourcing capabilities of the emerging Web Services framework provide a key to enabling these complex eco-systems. We explore the strategic and technological dimensions of Web Services and describe how they can be used to support dynamic business networks

Differentiating lymphovascular invasion from retraction artifact on histological specimen of breast carcinoma and their implications on prognosis.

On a pathological specimen of breast cancer cells, retraction artifact during histological processing mimics true lymphovascular invasion (LVI). The accurate determination of the presence or absence of LVI is a factor in determining risk of having a positive sentinel node, or having additional positive axillary nodes after a positive sentinel node biopsy in women with early-stage breast cancer. The determination of nodal risk influences the decision of the treating physicians as to whether a sentinel node biopsy or completion axillary dissection is necessary. On slide preparation, ideal factors favoring true LVI include: a definite endothelial lining, with endothelial nuclei that seem to protrude into the lymphatic space; invasion in one lymphatic vessel (LV) lumen with nearby cancer glands that have minimal or no retraction; a tumor embolus in a LV clear lumen with outside nearby tumor bulk; a tumor embolus that is different in shape than its surrounding clear LV space; and a positive stain for fibrin, CD31, or CD34 on tumor embolus periphery

407-3 Glutathione Peroxidase Prevents the Inactivation of Nitric Oxide and Restores the Inhibition of Platelet Function by S-Nitrosothiols

The interaction of nitric oxide (NO) with reactive oxygen species in the vasculature can inactivate NO leading to potentially adverse vascular consequences. Glutathione peroxidases (GSH-Px), a family of antioxidant enzymes present at reduced concentrations in plasma and platelets of patients with coronary artery disease, catalyze the reduction of hydrogen peroxide and lipid hydroperoxides (LOOH) by glutathione. Given the role of LOOH in platelet eicosanoid metabolism and their presence in atherosclerotic plaque, we investigated the effect of GSH-Px on the inhibition of platelet function by the naturally occurring NO donor, S-nitroso-glutathione (SNO-Glu). Subthreshold inhibitory concentrations of SNO-Glu were added to platelet-rich plasma, and aggregation was induced by arachidonate. The addition of GSHPx (0.2–20U/ml) to this system led to a dose-dependent inhibition of platelet aggregation with an IC50= 0.6U/ml GSH-Px (p < 0.05 by ANOVA). Superoxide dismutase (0.1–200U/ml), catalase (0.1–200U/ml), or GSH-Px without SNO-Glu did not alter platelet aggregation responses. The addi ion of GSH-Px to a subthreshold inhibitory concentration of sodium nitroprusside also did not affect platelet aggregation responses. LOOH increased platelet aggregation in the presence of SNO-Glu, an effect reversed by GSH-Px. Levels of cGMP were measured after platelets were incubated with SNO-Glu, exogenous LOOH, and GSH-Px. SNO-Glu alone increased cGMP levels, and this effect was attenuated by LOOH but restored by the addition of GSH-Px. GSH-Px activity was equivalent with either SNO-Glu or glutathione as cosubstrate. Incubation of SNO-Glu with GSH-Px led to a 48.5% decrease in the concentration of SNO-Glu as determined by HPLC-electrochemical detection. Incubation of SNO-Glu with albumin in the presence of GSH-Px led to increased formation of S-nitroso-albumin, a prevalent reservoir of EDRF in plasma. These results show that GSH-Px, at physiologically relevant concentrations, has a potent effect on NO-induced inhibition of platelet aggregation and that this enzyme may have two functions: (i) metabolism of LOOH, thereby preventing its inactivation of NO; and (ii) metabolism of SNO-Glu, thereby liberating NO and/or supporting further transnitrosation reactions These findings suggest that GSH-Px, in addition to its antioxidant functions, regulates the availability of NO in the vasculature and possibly alters plateletdependent thrombotic events

Where did the votes go? Reassessing American party realignments via vote transfers between major parties from 1860 to 2008

Political scientists have long debated theories of electoral party realignments. In this paper, we apply ecological inference methods to statistically analyze the transfer of votes within counties in US presidential elections since 1860. Through this analysis we are able to identify the major periods of party realignment in US history and the counties where these shifts took place. As a result, we are able to provide new insights into American electoral history, and provide strong evidence that the 2008 presidential election did not represent a realigning election as the phrase is generally understood