Pointwise characteristic factors for the multiterm return times theorem

This paper is an update and extension of a result the authors first proved in 2003. The goal of this paper is to study factors which are known to be L^2-characteristic for certain nonconventional averages and prove that these factors are pointwise characteristic for the multidimensional return times averages.Comment: 31 pages Submitted and Accepted to ETDS Dan Rudolph Memorial Volume. This version is the final accepted copy and includes all of the revisions recommended by the referee

Untersuchung innen und außen berippter, rohrförmiger, gasgekühlter Brennelemente

Die vorliegende Arbeit liefert einen Beitrag zur Entwicklung eines rohrförmigen innen und außen gekühlten Brennelementes für den Reaktortyp Natururan/Graphit/Gas. An sieben hierfür geeigneten Hüllrohren mit Längs-, Quer- und Pfeilrippen wurden mittlere und örtliche Wärmeübergangszahlen und mittlere Druckverlustbeiwerte gemessen. Die Untersuchungen erfolgten bezüglich Kühlgas, Druck, Temperatur, Massenstrom und Heizleistung unter Reaktorbedingungenim Hochdruckgaskreislauf des Instituts für Reaktorbauelemente. Die Aufteilung des Kühlgasmassenstromes in einen turbulenten inneren und äußeren Teilstrom wurde theoretisch berechnet und experimentell überprüft. Zur Beurteilung der einzelnen Rippenformen wurden in einer Rechnung Wärmeleistung, Gebläseleistung, Uran-, Rippenrohr- und Gastemperatur für einen vereinfachten Reaktorkühlkanal mit Originalabmessungen bestimmt. Die höchste Wärmeleistung wird unter Einhaltung aller Grenzen erreicht, wenn das Uranrohr außen und innen mit Pfeilrippenrohren umhüllt wird. Eine nur 11 % geringere Wärmeleistung wird erzielt, wenn das Uranrohr innen mit einem Längsrippenrohr umhüllt wird. Berücksichtigt man, daß beim Längsrippenrohr die erforderliche Gebläseleistung niedriger und die Herstellungskosten bedeutend geringer sind als beim Pfeilrippenrohr, so erkennt man, daß auch Längsrippenrohre als Innenhüllrohre durchaus geeignet sind

Fabrication of bismuth nanowires with a silver nanocrystal shadowmask

We fabricated bismuth (Bi) nanowires with low energy electron beam lithography using silver (Ag) nanocrystal shadowmasks and a subsequent chlorine reactive ion etching. Submicron-size metal contacts on the single Bi nanowire were successfully prepared by in situ focused ion beam metal deposition for transport measurements. The temperature dependent resistance measurements on the 50 nm wide Bi nanowires showed that the resistance increased with decreasing temperature, which is characteristic of semiconductors and insulators

Quantitative microbiology: a basis for food safety.

Because microorganisms are easily dispersed, display physiologic diversity, and tolerate extreme conditions, they are ubiquitous and may contaminate and grow in many food products. The behavior of microbial populations in foods (growth, survival, or death) is determined by the properties of the food (e.g., water activity and pH) and the storage conditions (e.g., temperature, relative humidity, and atmosphere). The effect of these properties can be predicted by mathematical models derived from quantitative studies on microbial populations. Temperature abuse is a major factor contributing to foodborne disease; monitoring temperature history during food processing, distribution, and storage is a simple, effective means to reduce the incidence of food poisoning. Interpretation of temperature profiles by computer programs based on predictive models allows informed decisions on the shelf life and safety of foods. In- or on-package temperature indicators require further development to accurately predict microbial behavior. We suggest a basis for a "universal" temperature indicator. This article emphasizes the need to combine kinetic and probability approaches to modeling and suggests a method to define the bacterial growth/no growth interface. Advances in controlling foodborne pathogens depend on understanding the pathogens' physiologic responses to growth constraints, including constraints conferring increased survival capacity

New insights into the structure of nanoporous carbons from NMR, Raman, and pair distribution function analysis

The structural characterization of nanoporous carbons is a challenging task as they generally lack long-range order and can exhibit diverse local structures. Such characterization represents an important step toward understanding and improving the properties and functionality of porous carbons, yet few experimental techniques have been developed for this purpose. Here we demonstrate the application of nuclear magnetic resonance (NMR) spectroscopy and pair distribution function (PDF) analysis as new tools to probe the local structures of porous carbons, alongside more conventional Raman spectroscopy. Together, the PDFs and the Raman spectra allow the local chemical bonding to be probed, with the bonding becoming more ordered for carbide-derived carbons (CDCs) synthesized at higher temperatures. The ring currents induced in the NMR experiment (and thus the observed NMR chemical shifts for adsorbed species) are strongly dependent on the size of the aromatic carbon domains. We exploit this property and use computer simulations to show that the carbon domain size increases with the temperature used in the carbon synthesis. The techniques developed here are applicable to a wide range of porous carbons and offer new insights into the structures of CDCs (conventional and vacuum-annealed) and coconut shell-derived activated carbons

Religious faith and psychosocial adaptation among stroke patients in Kuwait: A mixed method study

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2012 Springer Science+Business Media.Religious faith is central to life for Muslim patients in Kuwait, so it may influence adaptation and rehabilitation. This study explored quantitative associations among religious faith, self-efficacy, and life satisfaction in 40 female stroke patients and explored the influence of religion within stroke rehabilitation through qualitative interviews with 12 health professionals. The quantitative measure of religious faith did not relate to life satisfaction or self-efficacy in stroke patients. However, the health professionals described religious coping as influencing adaptation post-stroke. Fatalistic beliefs were thought to have mixed influences on rehabilitation. Measuring religious faith among Muslims through a standardized scale is debated. The qualitative accounts suggest that religious beliefs need to be acknowledged in stroke rehabilitation in Kuwait

"It’s sort of reaffirmed to me that I'm not a monster, I'm not a terrible person": sex offenders’ movements toward desistance via peer-support roles in prison

Individuals incarcerated in prisons across the United Kingdom and abroad are able to volunteer for a variety of peer-support roles, which are characterized by prisoner-to-prisoner helping. Some research has found that such roles can represent turning points in the lives of those who have offended and encourage movements toward desistance. This proposed redemptive influence is argued to result from the prosocial behaviors that such roles appear to elicit in their holders. The present study aims to explore the mechanics of this claimed influence. While a limited amount of research has attempted this on a general offending population, no research has done so with a sample of sexual offenders. Given the intensive treatment programs involved in such contexts, and the requirements for sexual offenders to demonstrate reduced risk, the authors believe those serving time for sexual offenses represent an important sample on which to explore the potentially redemptive properties of peer-support roles. To this end, 13 peer supporters participated in semistructured interviews. Transcripts were analyzed using a phenomenologically oriented thematic analysis. Results suggest that sexual offenders who adopt peer-support roles are able to live up to desired selves by “doing good” in prison, “giving back,” and consequently resisting negative labels. These benefits have been theoretically linked with better reintegration outcomes for sexual offenders, who are publicly denigrated in the extreme and find it especially difficult to (re)integrate. Suggestions regarding the future utility of such schemes are offered

Quantitative Analysis of Culture Using Millions of Digitized Books

We constructed a corpus of digitized texts containing about 4% of all books ever printed. Analysis of this corpus enables us to investigate cultural trends quantitatively. We survey the vast terrain of ‘culturomics,’ focusing on linguistic and cultural phenomena that were reflected in the English language between 1800 and 2000. We show how this approach can provide insights about fields as diverse as lexicography, the evolution of grammar, collective memory, the adoption of technology, the pursuit of fame, censorship, and historical epidemiology. Culturomics extends the boundaries of rigorous quantitative inquiry to a wide array of new phenomena spanning the social sciences and the humanities.MathematicsPsycholog