Phase field modeling of electrochemistry II: Kinetics

The kinetic behavior of a phase field model of electrochemistry is explored for advancing (electrodeposition) and receding (electrodissolution) conditions in one dimension. We described the equilibrium behavior of this model in [J. E. Guyer, W. J. Boettinger, J.A. Warren, and G. B. McFadden, ``Phase field modeling of electrochemistry I: Equilibrium'', cond-mat/0308173]. We examine the relationship between the parameters of the phase field method and the more typical parameters of electrochemistry. We demonstrate ohmic conduction in the electrode and ionic conduction in the electrolyte. We find that, despite making simple, linear dynamic postulates, we obtain the nonlinear relationship between current and overpotential predicted by the classical ``Butler-Volmer'' equation and observed in electrochemical experiments. The charge distribution in the interfacial double layer changes with the passage of current and, at sufficiently high currents, we find that the diffusion limited deposition of a more noble cation leads to alloy deposition with less noble species.Comment: v3: To be published in Phys. Rev. E v2: Attempt to work around turnpage bug. Replaced color Fig. 4a with grayscale 13 pages, 7 figures in 10 files, REVTeX 4, SIunits.sty, follows cond-mat/030817

Auswirkungen von PEN, einem Extrakt aus der Biomasse von Penicillium chrysogenum, auf Pathogene und Pflanzen

Der Ersatz von Kupfer und anderen Pestiziden ist eine der dringlichen Aufgaben der Forschung im biologischen Landbau. Beim direkten Pflanzenschutz stehen fungizid wirkende Substanzen, Biocontrol-Organismen und Pflanzenstärkungsmittel zur Diskussion. Das Konzept der Pflanzenstärkung ist seit langem im biologischen Landbau bekannt. Beispielsweise werden Kompostextrakte, Brennesselextrakte, aber auch kommerzialisierte Produkte aus Reynoutria sachalinensis oder Backpulver eingesetzt. Unter den Resistenzinduktoren (Elicitoren) sind vor allem diejenigen von grossem Interesse, die Resistenz gegen Pathogene auslösen, die ansonsten mit Kupfer bekämpft werden (Tamm, 2000). Der Dünger Agro Biosol (Biochemie GmbH, A-Kundl) weist nebst einer Düngerwirkung auch krankheitsvermindernde Eigenschaften auf. Dies legen Beobachtungen nahe, die bereits in den achtziger Jahren auf Grasflächen gemacht wurden, die mit Fusarium nivale befallen waren. Das aus der Penicillinproduktion gewonnene Trockenmycel ist frei von Penicillin. Agro Biosol enthält 6 % Gesamtstickstoff, 1 % Gesamtphosphor, 1 % Kali, sowie Spurenelemente und Vitamine (Naschberger, pers. Mitteilung). In der Schweiz ist Agro Biosol als Dünger im biologischen Landbau zugelassen (Tamm, Maurer & Alföldi, 2000). E. Mösinger (Sandoz Agro, CH - Witterswil) führte erste Versuche über die krankheitsunterdrückende Wirkung von Agro Biosol durch. Dazu wurde ein Extrakt des Trockenmycels von P. chrysogenum hergestellt, der die Kurzbezeichnung ‚PEN’ erhielt. Diese Untersuchungen von Mösinger und Mitarbeitern wiesen darauf hin, dass PEN an Tomaten und Gurken Resistenz induzieren kann. Ab 1997 wurde das Thema am FiBL weiterverfolgt. Mit den vorliegenden Untersuchungen wurden die Teilziele angestrebt (i) Verifizieren und Charakterisieren der resistenzinduzierenden Eigenschaften von PEN, (ii) Abklären des Potentials für eine Weiterentwicklung von PEN als kommerzialisierbaren Resistenzinduktor und (iii) Charakterisierung der phytotoxischen Eigenschaften von PEN als Ausgangspunkt für die Optimierung von Agro Biosol. Fazit: PEN, der Extrakt von Penicillium chrysogenum, kann bei zahlreichen Wirt- Pathogen-Systemen den Krankheitsbefall markant reduzieren. Dies ist insbesondere bei Krankheitserregern von Interesse, die ansonsten mit biotauglichen Produkten nur schwer kontrollierbar sind. Das Ausgangsmaterial wird als biotauglich eingeschätzt und steht in genügenden Mengen in konstanter Qualität zur Verfügung. Dies sind günstige Voraussetzungen, um einen neuartigen Resistenzinduktor für den biologischen Anbau bis zur Praxisreife zu entwickeln. PEN kann allerdings phytotoxische Effekte auslösen, die eine Praxisanwendung als Resistenzinduktor vorerst ausschliessen. Unsere Forschung hat gegenwärtig zwei Stossrichtungen. Einerseits werden die Effekte von PEN auf die Pflanzenphysiologie untersucht und die involvierten Stoffwechselprozesse detailliert abgeklärt. Andererseits suchen wir nach den aktiven Prinzipien, die für Resistenzinduktion und Phytotoxizität verantwortlich sind

G74-100 Feeding High Moisture Corn

In recent years the use of high moisture grain has become more popular due to the increased costs of handling and dry feed grains. For cattle feeders in particular, storing grains as high moisture is one practice that can improve their competitive position and reduce costs. Using high moisture grains allows greater opportunity to design a system that will minimize harvest, storage and feed processing costs. Grains such as sorghum and wheat have been stored as high moisture, but corn is the principal high moisture grain stored. High moisture corn can be processed and stored as whole shelled corn, ground shelled corn or ground ear corn. When deciding whether to dry or store high moisture corn, consider the following advantages and disadvantages

G74-100 Feeding High Moisture Corn

In recent years the use of high moisture grain has become more popular due to the increased costs of handling and dry feed grains. For cattle feeders in particular, storing grains as high moisture is one practice that can improve their competitive position and reduce costs. Using high moisture grains allows greater opportunity to design a system that will minimize harvest, storage and feed processing costs. Grains such as sorghum and wheat have been stored as high moisture, but corn is the principal high moisture grain stored. High moisture corn can be processed and stored as whole shelled corn, ground shelled corn or ground ear corn. When deciding whether to dry or store high moisture corn, consider the following advantages and disadvantages

A Survey of Laboratory Programs for First Year Medical Students

Basic science courses offered to freshmen medical students have been traditionally taught by didactic presentations and laboratory work. Various factors have prompted many departments to either markedly reduce the time allotted for the traditional, but more vulnerable, laboratory phase of these courses or drastically alter the content of the laboratory programs. Information concerning the desirability for such changes is incomplete and no evaluation has been developed to determine the effectiveness of change. Before beginning any further alterations in the laboratory programs at the Medical College of Virginia, it seemed desirable to determine anew what we wish to teach in the laboratory. This problem was approached in part by surveying the attitudes of other anatomy, biochemistry, and physiology departments

Annual Summary of Vital Statistics-2000

The birth rate in 2000 (preliminary data)was 14.8 births per 1000 population, an increase of 2% from 1999 (14.5). The fertility rate, births per 1000 women aged 15 to 44 years, increased 3% to 67.6 in 2000, compared with 65.9 in 1999. The 2000 increases in births and the fertility rate were the third consecutive yearly increases, the largest in many years, halting the steady decline in the number of births and fertility rates in the 1990s. Fertility rates for total white, non-Hispanic white, black, and Native American women each increased about 2% in 2000. The fertility rate for black women, which declined 19% from 1990 to 1996, has changed little since 1996. The rate for Hispanic women rose 4% in 2000 to reach the highest level since 1993. Birth rates for women 30 years or older continued to increase. The proportion of births to unmarried women remained about the same at one third, but the number of births rose 3%. The birth rate for teen mothers declined again for the ninth consecutive year. The use of timely prenatal care (83.2%) remained unchanged in 2000, and was essentially unchanged for non-Hispanic white (88.5%), black (74.2%), and Hispanic (74.4%) mothers. The number and rate of multiple births continued their dramatic rise, but all of the increase was confined to twins; for the first time in more than a decade, the number of triplet and higher-order multiple births declined (4%) between 1998 and 1999 (multiple birth information is not available in preliminary 2000 data). The overall increases in multiple births account, in part, for the lack of improvement in the percentage of low birth weight (LBW) births. LBW remained at 7.6% in 2000. The infant mortality rate (IMR) dropped to 6.9 per 1000 live births (preliminary data) in 2000 (the rate was 7.1 in 1999). The ratio of the IMR among black infants to that for white infants was 2.5 in 2000, the same as in 1999. Racial differences in infant mortality remain a major public health concern. The role of low birth weight in infant mortality remains a major issue. Among all of the states, Utah and Maine had the lowest IMRs. State-bystate differences in IMR reflect racial composition, the percentage LBW, and birth weight-specific neonatal mortality rates for each state. The United States continues to rank poorly in international comparisons of infant mortality. Expectation of life at birth reached a record high of 76.9 years for all gender and race groups combined. Death rates in the United States continue to decline. The age-adjusted death rate for suicide declined 4% between 1999 and 2000; homicide declined 7%. Death rates for children 19 years of age or less declined for 3 of the 5 leading causes in 2000; cancer and suicide levels did not change for children as a group. A large proportion of childhood deaths, however, continue to occur as a result of preventable injuries

Evaluation of smoking-specific and generic quality of life measures in current and former smokers in Germany and the United States

BACKGROUND: Health-related quality of life (QOL) surveys include generic measures that enable comparisons across conditions and measures that focus more specifically on one disease or condition. We evaluated the psychometric properties of German- and English-language versions of survey scales representing both types of measures in samples of current and former smokers. METHODS: TQOLITv1 integrates new measures of smoking-specific symptoms and QOL impact attributed to smoking with generic SF-36 Health Survey measures. For purposes of evaluation, cross-sectional data were analyzed for two independent samples. Disease-free (otherwise healthy) adults ages 23-55 used a tablet to complete surveys in a clinical trial in Germany (125 current and 54 former smokers). Online general population surveys were completed in the US by otherwise healthy current and former smokers (N = 149 and 110, respectively). Evaluations included psychometric tests of assumptions underlying scale construction and scoring, score distributions, and reliability. Tests of validity included cross-sectional correlations and analyses of variance based on a conceptual framework and hypotheses for groups differing in self-reported smoking behavior (current versus former smoker, cigarettes per day (CPD)) and severity of smoking symptoms in both samples and, in the German trial only, clinical parameters of biomarkers of exposure. RESULTS: Tests of scaling assumptions and internal consistency reliability (alpha = 0.71-0.79) of the smoking-specific measures were satisfactory, although ceiling effects attenuated correlations for former smokers in both samples. Correlational evidence supporting validity of smoking-specific symptom and impact measures included their substantial inter-correlation and higher correlations (than generic measures) with smoking behavior (favoring former over current groups) and CPD in both samples. In the German trial, both smoking-specific measures correlated significantly (p \u3c 0.05) with all four biomarkers. QOL impact attributed to smoking correlated with the SF-36 mental but not physical summary measures in both samples. CONCLUSIONS: German- and English-language TQOLITv1 surveys have comparable and satisfactory psychometric properties. Cross-sectional tests, including correlations with four biomarkers, support the validity of the new smoking-specific measures for use in studies of otherwise healthy smokers. Smoking-specific measures consistently performed better than generic QOL measures in all tests of validity