Monopoles and the Emergence of Black Hole Entropy

One of the remarkable features of black holes is that they possess a thermodynamic description, even though they do not appear to be statistical systems. We use self-gravitating magnetic monopole solutions as tools for understanding the emergence of this description as one goes from an ordinary spacetime to one containing a black hole. We describe how causally distinct regions emerge as a monopole solution develops a horizon. We define an entropy that is naturally associated with these regions and that has a clear connection with the Hawking-Bekenstein entropy in the critical black hole limit.Comment: 6 pages, one figure RevTe

Bulk Current Injection Testing of Close Proximity Cable Current Return, 1kHz to 1 MHz

This paper presents the results of an experiment examining the percentage of current that returns on adjacent wires or through a surrounding cable shield rather than through a shared conducting chassis. Simulation and measurement data are compared from 1 kHz 1 MHz for seven common cable configurations. The phenomenon is important to understand, because minimizing the return current path is vital in developing systems with low radiated emissions

Exploration and exploitation in the presence of network externalities

This paper examines the conditions under which exploration of a new, incompatible technologyis conducive to firm growth in the presence of network externalities. In particular, this studyis motivated bythe divergent evolutions of the PC and the workstation markets in response to a new technology: reduced instruction set computing (RISC). In the PC market, Intel has developed new microprocessors bymaintaining compatibilitywith the established architecture, whereas it was radicallyr eplaced byRISC in the workstation market. History indicates that unlike the PC market, the workstation market consisted of a large number of power users, who are less sensitive to compatibilitythan ordinaryusers. Our numerical analysis indicates that the exploration of a new, incompatible technologyis more likelyto increase the chance of firm growth when there are a substantial number of power users or when a new technologyis introduced before an established technologytakes off. (; ; ;

The integrin alpha 6 beta 4 is a laminin receptor

In this study, the putative laminin receptor function of the alpha 6 beta 4 integrin was assessed. For this purpose, we used a human cell line, referred to as clone A, that was derived from a highly invasive, colon adenocarcinoma. This cell line, which expresses the alpha 6 beta 4 integrin, adheres to the E8 and not to the P1 fragment of laminin. The adhesion of clone A cells to laminin is extremely rapid with half-maximal adhesion observed at 5 min after plating. Adhesion to laminin is blocked by GoH3, and alpha 6 specific antibody (60% inhibition), as well as by A9, a beta 4 specific antibody (30% inhibition). Most importantly, we demonstrate that alpha 6 beta 4 binds specifically to laminin-Sepharose columns in the presence of either Mg2+ or Mn2+ and it is eluted from these columns with EDTA but not with NaCl. The alpha 6 beta 4 integrin does not bind to collagen-Sepharose, but the alpha 2 beta 1 integrin does bind. Clone A cells do not express alpha 6 beta 1 as evidenced by the following observations: (a) no beta 1 integrin is detected in beta 1 immunoblots of GoH3 immunoprecipitates; and (b) no alpha 6 beta 1 integrin is seen in GoH3 immunoprecipitates of clone A extracts that had been immunodepleted of all beta 4 containing integrin using the A9 antibody. These data establish that laminin is a ligand for the alpha 6 beta 4 integrin and that this integrin can function as a laminin receptor independently of alpha 6 beta 1

Meningococcal Disease in Patients With Human Immunodeficiency Virus Infection: A Review of Cases Reported Through Active Surveillance in the United States, 2000-2008.

BackgroundAlthough human immunodeficiency virus (HIV) infection is an established risk factor for several bacterial infections, the association between HIV infection and meningococcal disease remains unclear.MethodsExpanded chart reviews were completed on persons with meningococcal disease and HIV infection reported from 2000 through 2008 from 9 US sites participating in an active population-based surveillance system for meningococcal disease. The incidence of meningococcal disease among patients meeting Centers for Disease Control and Prevention acquired immune deficiency syndrome (AIDS) surveillance criteria was estimated using data from the National HIV Surveillance System for the participating sites.ResultsThirty-three cases of meningococcal disease in individuals with HIV infection were reported from participating sites, representing 2.0% of all reported meningococcal disease cases. Most (75.8%) persons with HIV infection were adult males aged 25 to 64 years old. Among all meningococcal disease cases aged 25 to 64 years old, case fatality ratios were similar among HIV-infected and HIV-uninfected persons (13.3% vs 10.6%; P = .6). The cumulative, mean incidence of meningococcal disease among patients aged 25 to 64 years old with HIV infection ever classified as AIDS was 3.5 cases per 100000 person years (95% confidence interval [CI], 2.1-5.6), compared with 0.3 cases per 100000 person years (95% CI, 0.3-0.3) for persons of the same age group not reported to have AIDS (relative risk = 12.9; 95% CI, 7.9-20.9).ConclusionsIndividuals with HIV infection meeting the AIDS surveillance case definition have a higher incidence of meningococcal disease compared with the general adult population

Gravitational Properties of Monopole Spacetimes Near the Black Hole Threshold

Although nonsingular spacetimes and those containing black holes are qualitatively quite different, there are continuous families of configurations that connect the two. In this paper we use self-gravitating monopole solutions as tools for investigating the transition between these two types of spacetimes. We show how causally distinct regions emerge as the black hole limit is achieved, even though the measurements made by an external observer vary continuously. We find that near-critical solutions have a naturally defined entropy, despite the absence of a true horizon, and that this has a clear connection with the Hawking-Bekenstein entropy. We find that certain classes of near-critical solutions display naked black hole behavior, although they are not truly black holes at all. Finally, we present a numerical simulation illustrating how an incident pulse of matter can induce the dynamical collapse of a monopole into an extremal black hole. We discuss the implications of this process for the third law of black hole thermodynamics.Comment: 23 pages, 4 figures RevTe

The Lantern Vol. 26, No. 2, Spring 1958

• The Wise Man • Of Men and Lobsters • The Painting • The Ghost of Moon Mountain • Song for the Atomic Age • Opus I • Stillnesshttps://digitalcommons.ursinus.edu/lantern/1074/thumbnail.jp

Invasive Haemophilus influenzae Disease in Adults ≥65 Years, United States, 2011.

BackgroundSince the introduction of the Haemophilus influenzae serotype b vaccine, H influenzae epidemiology has shifted. In the United States, the largest burden of disease is now in adults aged ≥65 years. However, few data exist on risk factors for disease severity and outcome in this age group.MethodsA retrospective case-series review of invasive H influenzae infections in patients aged ≥65 years was conducted for hospitalized cases reported to Active Bacterial Core surveillance in 2011.ResultsThere were 299 hospitalized cases included in the analysis. The majority of cases were caused by nontypeable H influenzae, and the overall case fatality ratio (CFR) was 19.5%. Three or more underlying conditions were present in 63% of cases; 94% of cases had at least 1. Patients with chronic heart conditions (congestive heart failure, coronary artery disease, and/or atrial fibrillation) (odds ratio [OR], 3.27; 95% confidence interval [CI], 1.65-6.46), patients from private residences (OR, 8.75; 95% CI, 2.13-35.95), and patients who were not resuscitate status (OR, 2.72; 95% CI, 1.31-5.66) were more likely to be admitted to the intensive care unit (ICU). Intensive care unit admission (OR, 3.75; 95% CI, 1.71-8.22) and do not resuscitate status (OR, 12.94; 95% CI, 4.84-34.55) were significantly associated with death.ConclusionsWithin this age group, burden of disease and CFR both increased significantly as age increased. Using ICU admission as a proxy for disease severity, our findings suggest several conditions increased risk of disease severity and patients with severe disease were more likely to die. Further research is needed to determine the most effective approach to prevent H influenzae disease and mortality in older adults