Vedøy, Tord F
2014-11-01
This study examined if temporal variations in daily cigarette smoking and never smoking among groups with different levels of education fit the pattern proposed by the theory of diffusion of innovations (TDI), while taking into account the separate effects of age, period and birth cohort (APC). Aggregated data from nationally representative interview surveys from Norway from 1976 to 2010 was used to calculate probabilities of smoking using an APC approach in which the period variable was normalized to pick up short term cyclical effects. Results showed that educational differences in smoking over time were more strongly determined by birth cohort membership than variations in smoking behavior across the life course. The probability of daily smoking decreased faster across cohorts among higher compared to lower educated. In contrast, the change in probability of never having smoked across cohorts was similar in the two education groups, but stronger among men compared to women. Moreover, educational differences in both daily and never smoking increased among early cohorts and leveled off among late cohorts. The results emphasizes the importance of birth cohort for social change and are consistent with TDI, which posits that smoking behavior diffuse through the social structure over time.
Spatial gender-age-period-cohort analysis of pancreatic cancer mortality in Spain (1990–2013)
Etxeberria, Jaione; Goicoa, Tomás; López-Abente, Gonzalo; Riebler, Andrea
2017-01-01
Recently, the interest in studying pancreatic cancer mortality has increased due to its high lethality. In this work a detailed analysis of pancreatic cancer mortality in Spanish provinces was performed using recent data. A set of multivariate spatial gender-age-period-cohort models was considered to look for potential candidates to analyze pancreatic cancer mortality rates. The selected model combines features of APC (age-period-cohort) models with disease mapping approaches. To ensure model identifiability sum-to-zero constraints were applied. A fully Bayesian approach based on integrated nested Laplace approximations (INLA) was considered for model fitting and inference. Sensitivity analyses were also conducted. In general, estimated average rates by age, cohort, and period are higher in males than in females. The higher differences according to age between males and females correspond to the age groups [65, 70), [70, 75), and [75, 80). Regarding the cohort, the greatest difference between men and women is observed for those born between the forties and the sixties. From there on, the younger the birth cohort is, the smaller the difference becomes. Some cohort differences are also identified by regions and age-groups. The spatial pattern indicates a North-South gradient of pancreatic cancer mortality in Spain, the provinces in the North being the ones with the highest effects on mortality during the studied period. Finally, the space-time evolution shows that the space pattern has changed little over time. PMID:28199327
Age-period-cohort analysis of hepatitis A incidence rates in Korea from 2002 to 2012
2016-01-01
OBJECTIVES This study aimed to evaluate the epidemiology of hepatitis A in Korea from 2002 to 2012 using age-period-cohort analyses. METHODS We used claims data from the Korean National Health Insurance Corporation for the entire population. Census data from 2010 were used as the standard population. The incidence of hepatitis A was assumed to have a Poisson distribution, and the models and effects were evaluated using the intrinsic estimator method, the likelihood ratio, and the Akaike information criterion. RESULTS The incidence of hepatitis A gradually increased until 2007 (from 17.55 to 35.72 per 100,000 population) and peaked in 2009 (177.47 per 100,000 population). The highest incidence was observed among 27-29-year-old individuals when we omitted data from 2005 to 2007. From 2005 to 2007, the peak incidence was observed among 24-26-year-old individuals, followed by 27-29-year-olds. The best model fits were observed when the age-period-cohort variables were all considered at the same time for males, females, and the whole population. CONCLUSIONS The incidence of hepatitis A exhibited significant age-period-cohort effects; its incidence peaked in 2009 and was especially high among Koreans 20-39 years of age. These epidemiological patterns may help predict when high incidence rates of hepatitis A may occur in developing countries during their socioeconomic development. PMID:27703127
The marriage boom and marriage bust in the United States: An age-period-cohort analysis.
Schellekens, Jona
2017-03-01
In the 1950s and 1960s there was an unprecedented marriage boom in the United States. This was followed in the 1970s by a marriage bust. Some argue that both phenomena are cohort effects, while others argue that they are period effects. The study reported here tested the major period and cohort theories of the marriage boom and bust, by estimating an age-period-cohort model of first marriage for the years 1925-79 using census microdata. The results of the analysis indicate that the marriage boom was mostly a period effect, although there were also cohort influences. More specifically, the hypothesis that the marriage boom was mostly a response to rising wages is shown to be consistent with the data. However, much of the marriage bust can be accounted for by unidentified cohort influences, at least until 1980.
Delaruelle, Katrijn; Buffel, Veerle; Bracke, Piet
2015-11-01
Researchers have recently been investigating the temporal variation in the educational gradient in health. While there is abundant literature concerning age trajectories, theoretical knowledge about cohort differences is relatively limited. Therefore, in analogy with the life course perspective, we introduce two contrasting cohort-specific hypotheses. The diminishing health returns hypothesis predicts a decrease in educational disparities in health across cohorts. By contrast, the cohort accretion hypothesis suggests that the education-health gap will be more pronounced among younger cohorts. To shed light on this, we perform a hierarchical age-period-cohort analysis (HAPC), using data from a subsample of individuals between 25 and 85 years of age (N = 232,573) from 32 countries in the European Social Survey (six waves: 2002-2012). The analysis leads to three important conclusions. First, we observe a widening health gap between different educational levels over the life course. Second, we find that these educational differences in the age trajectories of health seem to strengthen with each successive birth cohort. However, the two age-related effects disappear when we control for employment status, household income, and family characteristics. Last, when adjusting for these mediators, we reveal evidence to support the diminishing health returns hypothesis, implying that it is primarily the direct association between education and health that decreases across cohorts. This finding raises concerns about potential barriers to education being a vehicle for empowerment and the promotion of health.
A Web Tool for Age-Period-Cohort Analysis of Cancer Incidence and Mortality Rates
Rosenberg, Philip S.; Check, David P.; Anderson, William F.
2014-01-01
BACKGROUND Age-period-cohort (APC) analysis can inform registry-based studies of cancer incidence and mortality, but concerns about statistical identifiability and interpretability, as well as the learning curves of statistical software packages, have limited its uptake. METHODS We implemented a panel of easy-to-interpret estimable APC functions and corresponding Wald tests in R code that can be accessed through a user-friendly web tool. RESULTS Input data for the web tool consist of age-specific numbers of events and person-years over time, in the form of a rate matrix of paired columns. Output functions include model-based estimators of cross-sectional and longitudinal age-specific rates; period and cohort rate ratios that incorporate the overall annual percentage change (net drift); and estimators of the age-specific annual percentage change (local drifts). The web tool includes built-in examples for teaching and demonstration. User data can be input from a Microsoft Excel worksheet or by uploading a comma-separated-value (csv) file. Model outputs can be saved in a variety of formats including R and Excel. CONCLUSIONS APC methodology can now be carried out through a freely-available user-friendly web tool. The tool can be accessed at http://analysistools.nci.nih.gov/apc/. IMPACT The web tool can help cancer surveillance researchers make important discoveries about emerging cancer trends and patterns. PMID:25146089
An International Contrast of Rates of Placental Abruption: An Age-Period-Cohort Analysis
Ananth, Cande V.; Keyes, Katherine M.; Hamilton, Ava; Gissler, Mika; Wu, Chunsen; Liu, Shiliang; Luque-Fernandez, Miguel Angel; Skjærven, Rolv; Williams, Michelle A.; Tikkanen, Minna; Cnattingius, Sven
2015-01-01
Background Although rare, placental abruption is implicated in disproportionately high rates of perinatal morbidity and mortality. Understanding geographic and temporal variations may provide insights into possible amenable factors of abruption. We examined abruption frequencies by maternal age, delivery year, and maternal birth cohorts over three decades across seven countries. Methods Women that delivered in the US (n = 863,879; 1979–10), Canada (4 provinces, n = 5,407,463; 1982–11), Sweden (n = 3,266,742; 1978–10), Denmark (n = 1,773,895; 1978–08), Norway (n = 1,780,271, 1978–09), Finland (n = 1,411,867; 1987–10), and Spain (n = 6,151,508; 1999–12) were analyzed. Abruption diagnosis was based on ICD coding. Rates were modeled using Poisson regression within the framework of an age-period-cohort analysis, and multi-level models to examine the contribution of smoking in four countries. Results Abruption rates varied across the seven countries (3–10 per 1000), Maternal age showed a consistent J-shaped pattern with increased rates at the extremes of the age distribution. In comparison to births in 2000, births after 2000 in European countries had lower abruption rates; in the US there was an increase in rate up to 2000 and a plateau thereafter. No birth cohort effects were evident. Changes in smoking prevalence partially explained the period effect in the US (P = 0.01) and Sweden (P<0.01). Conclusions There is a strong maternal age effect on abruption. While the abruption rate has plateaued since 2000 in the US, all other countries show declining rates. These findings suggest considerable variation in abruption frequencies across countries; differences in the distribution of risk factors, especially smoking, may help guide policy to reduce abruption rates. PMID:26018653
Should Age-Period-Cohort Studies Return to the Methodologies of the 1970s?
Masters, Ryan K.; Yang, Y. Claire; Powers, Daniel A.; Zheng, Hui; Land, Kenneth C.
2015-01-01
Social scientists have recognized the importance of age-period-cohort (APC) models for half a century, but have spent much of this time mired in debates about the feasibility of APC methods. Recently, a new class of APC methods based on modern statistical knowledge has emerged, offering potential solutions. In 2009, Reither, Hauser and Yang used one of these new methods – hierarchical APC (HAPC) modeling – to study how birth cohorts may have contributed to the U.S. obesity epidemic. They found that recent birth cohorts experience higher odds of obesity than their predecessors, but that ubiquitous period-based changes are primarily responsible for the rising prevalence of obesity. Although these findings have been replicated elsewhere, recent commentaries by Bell and Jones call them into question – along with the new class of APC methods. Specifically, Bell and Jones claim that new APC methods do not adequately address model identification and suggest that “solid theory” is often sufficient to remove one of the three temporal dimensions from empirical consideration. They also present a series of simulation models that purportedly show how the HAPC models estimated by Reither et al. (2009) could have produced misleading results. However, these simulation models rest on assumptions that there were no period effects, and associations between period and cohort variables and the outcome were perfectly linear. Those are conditions under which APC models should never be used. Under more tenable assumptions, our own simulations show that HAPC methods perform well, both in recovering the main findings presented by Reither et al. (2009) and the results reported by Bell and Jones. We also respond to critiques about model identification and theoretically-imposed constraints, finding little pragmatic support for such arguments. We conclude by encouraging social scientists to move beyond the debates of the 1970s and toward a deeper appreciation for modern APC
Temporal Trends of Suicide Mortality in Mainland China: Results from the Age-Period-Cohort Framework
Wang, Zhenkun; Wang, Jinyao; Bao, Junzhe; Gao, Xudong; Yu, Chuanhua; Xiang, Huiyun
2016-01-01
The aim of this study is to explore the long-term trends of suicide mortality in China. We implemented the age-period-cohort (APC) framework, using data from the Global Burden of Disease Study 2013. Our results showed that the net drift of suicide mortality was −4.727% (95% CI: −4.821% to −4.634%) per year for men and −6.633% (95% CI: −6.751% to −6.515%) per year for women, and the local drift values were below 0 in all age groups (p < 0.01 for all) for both sexes during the period of 1994–2013. Longitudinal age curves indicated that, in the same birth cohort, suicide death risk increased rapidly to peak at the life stage of 20–24 years old and 15–24 years old for men and women, respectively, and then showed a decelerated decline, followed by a rise thereafter after 54 years old for men and a slight one after 69 years old for women. The estimated period and cohort RRs were found to show similar monotonic downward patterns (significantly with p < 0.01 for all) for both sexes, with more quickly decreasing for women than for men during the whole period. The decreasing trend of suicide was likely to be related to the economic rapid growth, improvements in health care, enhancement on the level of education, and increasing awareness of suicide among the public in China. In addition, fast urbanization and the effective control of pesticides and rodenticides might be the special reasons behind these trends we observed in this study. PMID:27527195
Trends in hip fracture rates in Canada: an age-period-cohort analysis.
Jean, Sonia; O'Donnell, Siobhan; Lagacé, Claudia; Walsh, Peter; Bancej, Christina; Brown, Jacques P; Morin, Suzanne; Papaioannou, Alexandra; Jaglal, Susan B; Leslie, William D
2013-06-01
Age-standardized rates of hip fracture in Canada declined during the period 1985 to 2005. We investigated whether this incidence pattern is explained by period effects, cohort effects, or both. All hospitalizations during the study period with primary diagnosis of hip fracture were identified. Age- and sex-specific hip fracture rates were calculated for nineteen 5-year age groups and four 5-year calendar periods, resulting in 20 birth cohorts. The effect of age, calendar period, and birth cohort on hip fracture rates was assessed using age-period-cohort models as proposed by Clayton and Schiffers. From 1985 to 2005, a total of 570,872 hospitalizations for hip fracture were identified. Age-standardized rates for hip fracture have progressively declined for females and males. The annual linear decrease in rates per 5-year period were 12% for females and 7% for males (both p < 0.0001). Significant birth cohort effects were also observed for both sexes (p < 0.0001). Cohorts born before 1950 had a higher risk of hip fracture, whereas those born after 1954 had a lower risk. After adjusting for age and constant annual linear change (drift term common to both period and cohort effects), we observed a significant nonlinear birth cohort effect for males (p = 0.0126) but not for females (p = 0.9960). In contrast, the nonlinear period effect, after adjustment for age and drift term, was significant for females (p = 0.0373) but not for males (p = 0.2515). For males, we observed no additional nonlinear period effect after adjusting for age and birth cohort, whereas for females, we observed no additional nonlinear birth cohort effect after adjusting for age and period. Although hip fracture rates decreased in both sexes, different factors may explain these changes. In addition to the constant annual linear decrease, nonlinear birth cohort effects were identified for males, and calendar period effects were identified for females as possible explanations.
Rousselière, Damien; Rousselière, Samira
2016-01-11
The study of European attitudes toward biotechnologies underlines a situation that is relatively contrasting in Europe. However, as different effects of time can influence the social attitudes (a life-cycle effect, a generational effect, and an exogenous temporal effect potentially affecting the entire population), an appropriate methodology should be used. To this end, age-period-cohort-country models have thus been estimated based on Eurobarometer data from 1991 onward. Applied to different data subsets, these models give similar results underlining the importance of the life-cycle effects as well as the heterogeneity of the link between political affiliation and biotechnologies attitudes across the European countries.
Age-Period-Cohort Analysis of 1990–2003 Incidence Time Trends of Childhood Diabetes in Italy
Bruno, Graziella; Maule, Milena; Merletti, Franco; Novelli, Giulia; Falorni, Alberto; Iannilli, Antonio; Iughetti, Lorenzo; Altobelli, Emma; d'Annunzio, Giuseppe; Piffer, Silvano; Pozzilli, Paolo; Iafusco, Dario; Songini, Marco; Roncarolo, Federico; Toni, Sonia; Carle, Flavia; Cherubini, Valentino
2010-01-01
OBJECTIVE To investigate age-period-cohort effects on the temporal trend of type 1 diabetes in children age 0–14 years in Italian registries. RESEARCH DESIGN AND METHODS This report is based on 5,180 incident cases in the period 1990–2003 from the Registry for Type 1 Diabetes Mellitus in Italy (RIDI). Multilevel (random intercept) Poisson regression models were used to model the effects of sex, age, calendar time, and birth cohorts on temporal trends, taking into account the registry-level variance component. RESULTS The incidence rate was 12.26 per 100,000 person-years and significantly higher in boys (13.13 [95% CI 12.66–13.62]) than in girls (11.35 [10.90–11.82]). Large geographical variations in incidence within Italy were evident; incidence was highest in Sardinia, intermediate in Central-Southern Italy, and high in Northern Italy, particularly in the Trento Province, where the incidence rate was 18.67 per 100,000 person-years. An increasing temporal trend was evident (2.94% per year [95% CI 2.22–3.67]). With respect to the calendar period 1990–1992, the incidence rates increased linearly by 15, 27, 35, and 40% in the following time periods (P for trend < 0.001). With respect to the 1987–1993 birth cohort, the incidence rate ratio increased approximately linearly from 0.63 (95% CI 0.54–0.73) in the 1975–1981 cohort to 1.38 (1.06–1.80) in the 1999–2003 cohort. The best model, however, included sex, age, and a linear time trend (drift). CONCLUSIONS Large geographical variations and an increasing temporal trend in diabetes incidence are evident among type 1 diabetic children in Italy. Age-period-cohort analysis shows that the variation over time has a linear component that cannot be ascribed to either the calendar period or the birth cohort. PMID:20566665
Wang, Jinyao; Bai, Zhiqiang; Wang, Zhenkun; Yu, Chuanhua
2016-11-17
Background: As one of the most common cancers in the female population, cervical cancer has ranked as the second most incident gynecological cancer in recent years, trailing only breast cancer. We aimed to assess and compare the secular trends in cervical cancer mortality in China and the United States and analyze the independent effects of chronological age, time period and birth cohort using age-period-cohort (APC) analysis. Methods: We performed an age-period-cohort analysis using the intrinsic estimator method to estimate the independent effects of age, time period, and birth cohort on cervical cancer mortality. We collected mortality data for China and the United States from the WHO Mortality Database and China Health Statistical Yearbook database. Results: We examined the general trends in cervical mortality rates in China and the United States during the periods 1988-2012 and 1953-2012, respectively. The age-standardized mortality rates (ASMRs) for cervical cancer in urban China, rural China and the U.S. showed a general decreasing trend during the observation period, except for urban China, which experienced a significant increase beginning in 2002. The mortality rates for cervical cancer in the three areas showed a general increasing trend with age, regardless of the period effect. Period effects declined steadily in both rural China (from 0.19 to -0.26) and the U.S. (from -0.20 to -0.43); however, a slight increasing trend was identified (from -0.25 to 0.33) in urban China, which indicated that the risk of mortality increased with time. Cohort effects peaked in the cohort born in 1911-1915 in both rural China and urban China, declined consistently in the cohort born before 1950, and then decreased again in the cohort born after 1976-1980. The cohort effect in the U.S. peaked in the birth cohort born in 1876-1880, then leveled off and slightly decreased in younger generations. Conclusions: Our study showed that in general, cervical cancer mortality rates
Wang, Jinyao; Bai, Zhiqiang; Wang, Zhenkun; Yu, Chuanhua
2016-01-01
Background: As one of the most common cancers in the female population, cervical cancer has ranked as the second most incident gynecological cancer in recent years, trailing only breast cancer. We aimed to assess and compare the secular trends in cervical cancer mortality in China and the United States and analyze the independent effects of chronological age, time period and birth cohort using age-period-cohort (APC) analysis. Methods: We performed an age-period-cohort analysis using the intrinsic estimator method to estimate the independent effects of age, time period, and birth cohort on cervical cancer mortality. We collected mortality data for China and the United States from the WHO Mortality Database and China Health Statistical Yearbook database. Results: We examined the general trends in cervical mortality rates in China and the United States during the periods 1988–2012 and 1953–2012, respectively. The age-standardized mortality rates (ASMRs) for cervical cancer in urban China, rural China and the U.S. showed a general decreasing trend during the observation period, except for urban China, which experienced a significant increase beginning in 2002. The mortality rates for cervical cancer in the three areas showed a general increasing trend with age, regardless of the period effect. Period effects declined steadily in both rural China (from 0.19 to −0.26) and the U.S. (from −0.20 to −0.43); however, a slight increasing trend was identified (from −0.25 to 0.33) in urban China, which indicated that the risk of mortality increased with time. Cohort effects peaked in the cohort born in 1911–1915 in both rural China and urban China, declined consistently in the cohort born before 1950, and then decreased again in the cohort born after 1976–1980. The cohort effect in the U.S. peaked in the birth cohort born in 1876–1880, then leveled off and slightly decreased in younger generations. Conclusions: Our study showed that in general, cervical cancer
Rughiniș, Cosima; Humă, Bogdana
2015-12-01
In this paper we argue that quantitative survey-based social research essentializes age, through specific rhetorical tools. We outline the device of 'socio-demographic variables' and we discuss its argumentative functions, looking at scientific survey-based analyses of adult scientific literacy, in the Public Understanding of Science research field. 'Socio-demographics' are virtually omnipresent in survey literature: they are, as a rule, used and discussed as bundles of independent variables, requiring little, if any, theoretical and measurement attention. 'Socio-demographics' are rhetorically effective through their common-sense richness of meaning and inferential power. We identify their main argumentation functions as 'structure building', 'pacification', and 'purification'. Socio-demographics are used to uphold causal vocabularies, supporting the transmutation of the descriptive statistical jargon of 'effects' and 'explained variance' into 'explanatory factors'. Age can also be studied statistically as a main variable of interest, through the age-period-cohort (APC) disambiguation technique. While this approach has generated interesting findings, it did not mitigate the reductionism that appears when treating age as a socio-demographic variable. By working with age as a 'socio-demographic variable', quantitative researchers convert it (inadvertently) into a quasi-biological feature, symmetrical, as regards analytical treatment, with pathogens in epidemiological research.
Tu, Yu-Kang; Krämer, Nicole; Lee, Wen-Chung
2012-07-01
In the analysis of trends in health outcomes, an ongoing issue is how to separate and estimate the effects of age, period, and cohort. As these 3 variables are perfectly collinear by definition, regression coefficients in a general linear model are not unique. In this tutorial, we review why identification is a problem, and how this problem may be tackled using partial least squares and principal components regression analyses. Both methods produce regression coefficients that fulfill the same collinearity constraint as the variables age, period, and cohort. We show that, because the constraint imposed by partial least squares and principal components regression is inherent in the mathematical relation among the 3 variables, this leads to more interpretable results. We use one dataset from a Taiwanese health-screening program to illustrate how to use partial least squares regression to analyze the trends in body heights with 3 continuous variables for age, period, and cohort. We then use another dataset of hepatocellular carcinoma mortality rates for Taiwanese men to illustrate how to use partial least squares regression to analyze tables with aggregated data. We use the second dataset to show the relation between the intrinsic estimator, a recently proposed method for the age-period-cohort analysis, and partial least squares regression. We also show that the inclusion of all indicator variables provides a more consistent approach. R code for our analyses is provided in the eAppendix.
Mortality of breast cancer in Taiwan, 1971-2010: temporal changes and an age-period-cohort analysis.
Ho, M-L; Hsiao, Y-H; Su, S-Y; Chou, M-C; Liaw, Y-P
2015-01-01
The current paper describes the age, period and cohort effects on breast cancer mortality in Taiwan. Female breast cancer mortality data were collected from the Taiwan death registries for 1971-2010. The annual percentage changes, age- standardised mortality rates (ASMR) and age-period-cohort model were calculated. The mortality rates increased with advancing age groups when fixing the period. The percentage change in the breast cancer mortality rate increased from 54.79% at aged 20-44 years, to 149.78% in those aged 45-64 years (between 1971-75 and 2006-10). The mortality rates in the 45-64 age group increased steadily from 1971 to 1975 and 2006-10. The 1951 birth cohorts (actual birth cohort; 1947-55) showed peak mortalities in both the 50-54 and 45-49 age groups. We found that the 1951 birth cohorts had the greatest mortality risk from breast cancer. This might be attributed to the DDT that was used in large amounts to prevent deaths from malaria in Taiwan. However, future researches require DDT data to evaluate the association between breast cancer and DDT use.
Gao, Xudong; Wang, Zhenkun; Kong, Chan; Yang, Fen; Wang, Ying; Tan, Xiaodong
2017-02-23
Background: Esophageal cancer is one of the most common cancers in rural China. The aim of this study was to describe the time trends of esophageal cancer mortality in rural China and to better elucidate the causes of these trends. Methods: The mortality data were obtained from the World Health Organization Mortality Database and the China Health Statistical Yearbook Database. The mortality data were analyzed with age-period-cohort (APC) analysis. Results: Our study indicates that the Age-Standardized Mortality Rates (ASMRs) in rural China generally decreased from 1989 to 2003, and thereafter increased until the year 2008 in both sexes. After 2008, the ASMRs decreased again. The results of APC analysis suggest that the general decrease in esophageal cancer mortality in rural China from 1989 to 2003 might be caused by the downtrend of the cohort effects and period effects, while the general increase in mortality from 2004 to 2008 might be caused by the uptrend of the period effects. The decrease in mortality after 2008 may be relevant to the Four Trillion RMB Investment Plan launched by the Chinese Government. Conclusions: The declining cohort effects were probably related to the improvement of socioeconomic status in childhood and the decreasing consumptions of alcohol drinking and smoking, while the trends of the period effects were relevant to the changes in the dietary pattern. Our findings may help predict future changes in esophageal cancer mortality.
Gao, Xudong; Wang, Zhenkun; Kong, Chan; Yang, Fen; Wang, Ying; Tan, Xiaodong
2017-01-01
Background: Esophageal cancer is one of the most common cancers in rural China. The aim of this study was to describe the time trends of esophageal cancer mortality in rural China and to better elucidate the causes of these trends. Methods: The mortality data were obtained from the World Health Organization Mortality Database and the China Health Statistical Yearbook Database. The mortality data were analyzed with age-period-cohort (APC) analysis. Results: Our study indicates that the Age-Standardized Mortality Rates (ASMRs) in rural China generally decreased from 1989 to 2003, and thereafter increased until the year 2008 in both sexes. After 2008, the ASMRs decreased again. The results of APC analysis suggest that the general decrease in esophageal cancer mortality in rural China from 1989 to 2003 might be caused by the downtrend of the cohort effects and period effects, while the general increase in mortality from 2004 to 2008 might be caused by the uptrend of the period effects. The decrease in mortality after 2008 may be relevant to the Four Trillion RMB Investment Plan launched by the Chinese Government. Conclusions: The declining cohort effects were probably related to the improvement of socioeconomic status in childhood and the decreasing consumptions of alcohol drinking and smoking, while the trends of the period effects were relevant to the changes in the dietary pattern. Our findings may help predict future changes in esophageal cancer mortality. PMID:28241504
Gill, Tiffany K.; Price, Kay; Warmington, Rosemary; Taylor, Anne W.
2016-01-01
Background The ongoing need for an availability of informal carers is taking on greater relevance as the global burden of disease transitions from acute fatal diseases to long term morbidity. Growing evidence suggests that extra burden on family carers may further impact on their health and ability to provide care. Important as it is to monitor the prevalence of those conditions which influence the burden of disease, it is also important to monitor the prevalence and health profiles of those who provide the informal care. The aim of this study was to demonstrate the prevalence and demographics of adult carers aged 15 and over in the state of South Australia over 20 years between 1994 and 2014. Methods Data from nine representative, cross-sectional population surveys, conducted in South Australia, Australia were used, (total N = 26,788 and n = 1,504 carers). The adjusted prevalence estimate of carers and their demographic characteristics were determined. So as to examine whether there were any generational effects on the prevalence of carers, an Age-Period Cohort (APC) analysis was undertaken. Results The prevalence estimates of carers increased during the two decades from 3.7% in 1994 to 6.7% by 2014. Large increases in the proportion of retired carers, those aged 70 years and over, those carers employed, and those with higher educational qualifications were observed. There were also larger proportions of respondents with a country of birth other than Australia, UK, Ireland and European counties. The APC analysis illustrated an increasing prevalence rate over each decade for carers aged 20–80 years, especially for those over the age of 60 years. Conclusions The results illustrate changing carer characteristics and carer prevalence estimates in South Australia as new generations of carers take on the caring role. There is a need to include questions regarding informal carers within ongoing mainstream population surveys, particularly at state levels, so as to plan
Gero, Krisztina; Eshak, Ehab S.; Ma, Enbo; Takahashi, Hideto; Noda, Hiroyuki; Iso, Hiroyasu
2015-01-01
Background The objective of this study was to examine long-term trends in rates of ischaemic heart disease (IHD) mortality, a leading cause of mortality in Hungary. The study examined the effects of age, period, and cohort on IHD mortality rates and compared mortality rates between the capital (Budapest) and non-capital counties. Methods Data on IHD deaths and population censuses were obtained from the Hungarian Central Statistical Office. Age-period-cohort analysis utilized nine age-group classes for ages 40 to 84 years, eight time periods from 1970 to 2009, and 16 birth cohorts from 1886 to 1969. Results Age-adjusted IHD mortality rates for men and for women generally increased from 1970 to 1993 and from 1980 to 1999, respectively, decreasing thereafter for both sexes. IHD mortality rates for men and for women from Budapest were lower from 1991 and from 1970, respectively, than corresponding rates in non-capital counties, with the difference increasing after 1999. Age had a more significant influence on mortality rates for women than for men. The period effect increased from 1972 to 1982 and decreased thereafter for men, while the period effect decreased consistently for women from 1972 to 2007. The decline in period effect for both sexes was larger for individuals from the capital than for those from non-capital counties. The cohort effect for both sexes declined from birth years 1890 to 1965, with a steeper decline for individuals from the capital than for those from non-capital counties. Conclusions The findings indicate a need for programs in Hungary for IHD prevention, especially for non-capital counties. PMID:25986153
Pesce, Giancarlo
2016-01-01
Chronic lower respiratory diseases (CLRDs) are a major cause of morbidity and mortality worldwide. The objectives of this study were to estimate the trends in CLRD mortality in Italy, and the specific contributions of age, time period and birth cohort in driving these trends. Population and cause-of-death data in Italy between 1979 and 2010 were collected from the World Health Organization website. Age-specific mortality rates for CLRDs, and effects for age, time period and birth cohort on mortality trends were estimated using age-period-cohort models. Chronic obstructive pulmonary disease (COPD) and chronic bronchitis represent nearly 98% of the deaths from CLRDs. Despite the overall number of deaths have been stable (in men) or increasing (in women), the age-standardised rates have been steadily decreasing from 1979 to 2010, passing from 104.3 to 55.4 per 100 000 person-years in men and from 32.2 to 19.6 per 100 000 person-years in women. The average relative annual decrease was -3.6% in men and -2.7% in women. Since the end of the 1990s, the decreasing trend of CLRD mortality has started to level off, in particular in women. The decrease in CLRD mortality rates has been more accentuated in more recent cohorts and in younger age groups. Both birth cohort and time period significantly affected the CLRD mortality rates, suggesting that changes in the spread of risk factors (smoking habits, early-life and occupational exposures) across different birth cohorts, as well as in advanced in healthcare and medical practice, may have played a major role in secular changes in COPD mortality rates in Italy.
Time trend and age-period-cohort effect on kidney cancer mortality in Europe, 1981–2000
Pérez-Farinós, Napoleón; López-Abente, Gonzalo; Pastor-Barriuso, Roberto
2006-01-01
Background The incorporation of diagnostic and therapeutic improvements, as well as the different smoking patterns, may have had an influence on the observed variability in renal cancer mortality across Europe. This study examined time trends in kidney cancer mortality in fourteen European countries during the last two decades of the 20th century. Methods Kidney cancer deaths and population estimates for each country during the period 1981–2000 were drawn from the World Health Organization Mortality Database. Age- and period-adjusted mortality rates, as well as annual percentage changes in age-adjusted mortality rates, were calculated for each country and geographical region. Log-linear Poisson models were also fitted to study the effect of age, death period, and birth cohort on kidney cancer mortality rates within each country. Results For men, the overall standardized kidney cancer mortality rates in the eastern, western, and northern European countries were 20, 25, and 53% higher than those for the southern European countries, respectively. However, age-adjusted mortality rates showed a significant annual decrease of -0.7% in the north of Europe, a moderate rise of 0.7% in the west, and substantial increases of 1.4% in the south and 2.0% in the east. This trend was similar among women, but with lower mortality rates. Age-period-cohort models showed three different birth-cohort patterns for both men and women: a decrease in mortality trend for those generations born after 1920 in the Nordic countries, a similar but lagged decline for cohorts born after 1930 in western and southern European countries, and a continuous increase throughout all birth cohorts in eastern Europe. Similar but more heterogeneous regional patterns were observed for period effects. Conclusion Kidney cancer mortality trends in Europe showed a clear north-south pattern, with high rates on a downward trend in the north, intermediate rates on a more marked rising trend in the east than in the
Yu, Ruby; Wong, Moses; Chang, Billy; Lai, Xin; Lum, C M; Auyeung, T W; Lee, Jenny; Tsoi, Kelvin; Lee, Ruby; Woo, Jean
2016-01-01
Background To examine the trends in activities of daily living (ADL) disability in older Chinese adults in Hong Kong between 2001 and 2012. Methods Using data from the Elderly Health Centres (EHCs) of the Department of Health comprising a total of 54 808 community-dwelling Chinese adults aged ≥65 years in 1 early cohort (1904–1917) and 10 3-year birth cohorts (1918–1920, 1921–1923, 1924–1926, 1927–1929, 1930–1932, 1933–1935, 1936–1938, 1939–1941, 1942–1944, 1945–1947), we examined trends in ADL disability by using age-period-cohort (APC) models. ADL disability was defined as being unable to perform at least 1 of 7 ADL activities (bathing, dressing, toileting, transferring, feeding, grooming, walking) independently. Cross-classified random-effects logistic regressions were performed for each of the APC trends with adjustment for age, period, cohort, sociodemographic, lifestyle, comorbidity and self-rated health. Results The mean age of the cohort was 70.9±4.7 (range 65–99) years. The prevalence rate of ADL disability was 1.6%. ADL disability increased with age (p<0.001) and the gradient of the increase was steeper in the older age groups. At the same age, women (1.7%) were more likely to report ADL disability than men (1.4%, p=0.001). For both genders, there was an increase in ADL disability between 2003 and 2012; adjustment for age, cohort and other covariates has diminished the trends observed among men. There was no cohort effect in ADL disability. Conclusions ADL disability in older adults has increased over the last decade. Further study is required to identify possible causes behind the disability trends. PMID:27979837
Classical approach in atomic physics
NASA Astrophysics Data System (ADS)
Solov'ev, E. A.
2011-12-01
The application of a classical approach to various quantum problems - the secular perturbation approach to quantization of a hydrogen atom in external fields and a helium atom, the adiabatic switching method for calculation of a semiclassical spectrum of a hydrogen atom in crossed electric and magnetic fields, a spontaneous decay of excited states of a hydrogen atom, Gutzwiller's approach to Stark problem, long-lived excited states of a helium atom discovered with the help of Poincaré section, inelastic transitions in slow and fast electron-atom and ion-atom collisions - is reviewed. Further, a classical representation in quantum theory is discussed. In this representation the quantum states are treated as an ensemble of classical states. This approach opens the way to an accurate description of the initial and final states in classical trajectory Monte Carlo (CTMC) method and a purely classical explanation of tunneling phenomenon. The general aspects of the structure of the semiclassical series such as renormgroup symmetry, criterion of accuracy and so on are reviewed as well.
Chauvel, Louis; Leist, Anja K.; Ponomarenko, Valentina
2016-01-01
Birth cohort effects in suicide rates are well established, but to date there is no methodological approach or framework to test the temporal stability of these effects. We use the APC-Detrended (APCD) model to robustly estimate intensity of cohort effects identifying non-linear trends (or ‘detrended’ fluctuations) in suicide rates. The new APC-Hysteresis (APCH) model tests temporal stability of cohort effects. Analysing suicide rates in 25 WHO countries (periods 1970–74 to 2005–09; ages 20–24 to 70–79) with the APCD method, we find that country-specific birth cohort membership plays an important role in suicide rates. Among 25 countries, we detect 12 nations that show deep contrasts among cohort-specific suicide rates including Italy, Australia and the United States. The APCH method shows that cohort fluctuations are not stable across the life course but decline in Spain, France and Australia, whereas they remain stable in Italy, the United Kingdom and the Netherlands. We discuss the Spanish case with elevated suicide mortality of cohorts born 1965–1975 which declines with age, and the opposite case of the United States, where the identified cohort effects of those born around 1960 increase smoothly, but statistically significant across the life course. PMID:27442027
Wang, Zhenkun; Bao, Junzhe; Yu, Chuanhua; Wang, Jinyao; Li, Chunhui
2015-12-04
To describe the temporal trends of breast cancer mortality in East Asia and to better understand the causes of these trends, we analyzed the independent effects of chronological age, time period and birth cohort on breast cancer mortality trends using age-period-cohort (APC) analysis. We chose three main countries in East Asia, namely China, South Korea, and Japan, which have reported death status to the WHO Mortality Database, and used the United States as a comparison population. Our study shows that in general, breast cancer mortality rates in females increased in all three East Asian countries throughout the study period. By APC analysis, we confirmed that there is, in fact, a difference in age-specific mortality rate patterns between the Eastern and the Western countries, which is presumably caused by the two-disease model. While the cause of the decrease from approximately the 1950s generation is still in question, we believe that increasing general awareness and improvements in the health-care system have made a significant contribution to it. Although the age and cohort effects are relatively strong, the period effect may be a more critical factor in the mortality trend, mainly reflecting the increase in exposures to carcinogens and behavioral risk factors.
Marinaccio, Alessandro; Montanaro, Fabio; Mastrantonio, Marina; Uccelli, Raffaella; Altavista, Pierluigi; Nesti, Massimo; Costantini, Adele Seniori; Gorini, Giuseppe
2005-05-20
Italy was the second main asbestos producer in Europe, after the Soviet Union, until the end of the 1980s, and raw asbestos was imported on a large scale until 1992. The Italian pattern of asbestos consumption lags on average about 10 years behind the United States, Australia, the United Kingdom and the Nordic countries. Measures to reduce exposure were introduced in the mid-1970s in some workplaces. In 1986, limitations were imposed on the use of crocidolite and in 1992 asbestos was definitively banned. We have used primary pleural cancer mortality figures (1970-1999) to predict mortality from mesothelioma among Italian men in the next 30 years by age-cohort-period models and by a model based on asbestos consumption figures. The pleural cancer/mesothelioma ratio and mesothelioma misdiagnosis in the past were taken into account in the analysis. Estimated risks of birth cohorts born after 1945 decrease less quickly in Italy than in other Western countries. The findings predict a peak with about 800 mesothelioma annual deaths in the period 2012-2024. Results estimated using age-period-cohort models were similar to those obtained from the asbestos consumption model.
Wang, Zhenkun; Bao, Junzhe; Yu, Chuanhua; Wang, Jinyao; Li, Chunhui
2015-01-01
To describe the temporal trends of breast cancer mortality in East Asia and to better understand the causes of these trends, we analyzed the independent effects of chronological age, time period and birth cohort on breast cancer mortality trends using age-period-cohort (APC) analysis. We chose three main countries in East Asia, namely China, South Korea, and Japan, which have reported death status to the WHO Mortality Database, and used the United States as a comparison population. Our study shows that in general, breast cancer mortality rates in females increased in all three East Asian countries throughout the study period. By APC analysis, we confirmed that there is, in fact, a difference in age-specific mortality rate patterns between the Eastern and the Western countries, which is presumably caused by the two-disease model. While the cause of the decrease from approximately the 1950s generation is still in question, we believe that increasing general awareness and improvements in the health-care system have made a significant contribution to it. Although the age and cohort effects are relatively strong, the period effect may be a more critical factor in the mortality trend, mainly reflecting the increase in exposures to carcinogens and behavioral risk factors. PMID:26690183
Kramer, Michael R; Valderrama, Amy L; Casper, Michele L
2015-08-15
Against the backdrop of late 20th century declines in heart disease mortality in the United States, race-specific rates diverged because of slower declines among blacks compared with whites. To characterize the temporal dynamics of emerging black-white racial disparities in heart disease mortality, we decomposed race-sex-specific trends in an age-period-cohort (APC) analysis of US mortality data for all diseases of the heart among adults aged ≥35 years from 1973 to 2010. The black-white gap was largest among adults aged 35-59 years (rate ratios ranged from 1.2 to 2.7 for men and from 2.3 to 4.0 for women) and widened with successive birth cohorts, particularly for men. APC model estimates suggested strong independent trends across generations ("cohort effects") but only modest period changes. Among men, cohort-specific black-white racial differences emerged in the 1920-1960 birth cohorts. The apparent strength of the cohort trends raises questions about life-course inequalities in the social and health environments experienced by blacks and whites which could have affected their biomedical and behavioral risk factors for heart disease. The APC results suggest that the genesis of racial disparities is neither static nor restricted to a single time scale such as age or period, and they support the importance of equity in life-course exposures for reducing racial disparities in heart disease.
Kerr, William C.; Greenfield, Thomas K.; Ye, Yu; Bond, Jason; Rehm, Jürgen
2012-01-01
Aims To estimate age-period-cohort models predicting alcohol volume, heavy drinking and beverage-specific alcohol volume in order to evaluate whether the 1976–1985 birth cohorts drink relatively heavily. Design Data from seven cross-sectional surveys of the US conducted between 1979 and 2010 were utilized in negative binomial generalized linear models of age, period and cohort effects predicting alcohol measures. Setting General population surveys of the US. Participants 36,432 US adults (aged 18 or older). Measurements Monthly number of alcohol drinks, beer, wine and spirits drinks and days drinking 5 or more drinks in the past year derived from beverage-specific graduated frequency questions. Findings Relative to the reference 1956–60 birth cohort, men in the 1976–1980 cohort for were found to consume more alcohol (Incidence rate ratio (IRR) =1.222: CI 1.07–1.39) and to have more 5+ days (IRR=1.365: CI 1.09–1.71) as were men in the 1980–85 cohort for volume (IRR=1.284: CI 1.10–1.50) and 5+ days (IRR=1.437: CI 1.09–1.89). For women, those in the 1980–85 cohort were found to have higher alcohol volume (IRR=1.299: CI 1.07–1.58) and more 5+ days (IRR=1.547: CI 1.01–2.36). Beverage-specific models found different age patterns of volume by beverage with a flat age pattern for both genders’ spirits and women’s wine, an increasing age pattern for men’s wine and a declining age pattern from the early 20’s for beer. Conclusions In the United States, men born between 1976 and 1985, and women born between 1981 and 1985 have higher alcohol consumption than in earlier or later years. PMID:22897662
Quantum approach to classical statistical mechanics.
Somma, R D; Batista, C D; Ortiz, G
2007-07-20
We present a new approach to study the thermodynamic properties of d-dimensional classical systems by reducing the problem to the computation of ground state properties of a d-dimensional quantum model. This classical-to-quantum mapping allows us to extend the scope of standard optimization methods by unifying them under a general framework. The quantum annealing method is naturally extended to simulate classical systems at finite temperatures. We derive the rates to assure convergence to the optimal thermodynamic state using the adiabatic theorem of quantum mechanics. For simulated and quantum annealing, we obtain the asymptotic rates of T(t) approximately (pN)/(k(B)logt) and gamma(t) approximately (Nt)(-c/N), for the temperature and magnetic field, respectively. Other annealing strategies are also discussed.
Anderson, R W G; Searson, D J
2015-02-01
A novel application of age-period-cohort methods are used to explain changes in vehicle based crash rates in New South Wales, Australia over the period 2003-2010. Models are developed using vehicle age, crash period and vehicle cohort to explain changes in the rate of single vehicle driver fatalities and injuries in vehicles less than 13 years of age. Large declines in risk are associated with vehicle cohorts built after about 1996. The decline in risk appears to have accelerated to 12 percent per vehicle cohort year for cohorts since 2004. Within each cohort, the risk of crashing appears to be a minimum at two years of age and increases as the vehicle ages beyond this. Period effects (i.e., other road safety measures) between 2003 and 2010 appear to have contributed to declines of up to about two percent per annum to the driver-fatality single vehicle crash rate, and possibly only negligible improvements to the driver-injury single vehicle crash rate. Vehicle improvements appear to have been responsible for a decline in per-vehicle crash risk of at least three percent per calendar year for both severity levels over the same period. Given the decline in risk associated with more recent vehicle cohorts and the dynamics of fleet turnover, continued declines in per-vehicle crash risk over coming years are almost certain.
Rediscovering the Classics: The Project Approach.
ERIC Educational Resources Information Center
Townsend, Ruth; Lubell, Marcia
Focusing on seven classics of literature that are most challenging for teachers and students, but which are also a part of the high school literary canon, this book shares ways to create a learner-centered classroom for the study of literature. For each of the seven classics, the book "walks teachers through" the teaching-learning…
Classical field approach to quantum weak measurements.
Dressel, Justin; Bliokh, Konstantin Y; Nori, Franco
2014-03-21
By generalizing the quantum weak measurement protocol to the case of quantum fields, we show that weak measurements probe an effective classical background field that describes the average field configuration in the spacetime region between pre- and postselection boundary conditions. The classical field is itself a weak value of the corresponding quantum field operator and satisfies equations of motion that extremize an effective action. Weak measurements perturb this effective action, producing measurable changes to the classical field dynamics. As such, weakly measured effects always correspond to an effective classical field. This general result explains why these effects appear to be robust for pre- and postselected ensembles, and why they can also be measured using classical field techniques that are not weak for individual excitations of the field.
An Approach to Teaching Classical Chinese Poetry.
ERIC Educational Resources Information Center
Hung, Ming-shui
1980-01-01
English translations can be used to teach classical Chinese poetry to students above the intermediate level who have a limited vocabulary. To overcome this deficiency, and to bridge the gap between vernacular and literary Chinese, several texts are suggested. Examples are given to show the benefit of English translations. (PJM)
NASA Astrophysics Data System (ADS)
Henner, Victor K.; Klots, Andrey; Belozerova, Tatyana
2016-12-01
Problems of interacting quantum magnetic moments become exponentially complex with increasing number of particles. As a result, classical equations are often used to model spin systems. In this paper we show that a classical spins based approach can be used to describe the phenomena essentially quantum in nature such as of the Pake doublet.
New Approaches to the Teaching of the Classics.
ERIC Educational Resources Information Center
Masciantonio, Rudolph, Ed.; Weislogel, Stephen, Ed.
This four-part report of the 1971-72 Classical Association of the Atlantic States Working Committee deals with the rationale for new approaches and curriculums for schools and colleges. Implications of the new approaches in teacher education are also teated. The major section treating new model curriculums and approaches includes discussion of:…
A Lagrangian approach to classical thermodynamics
NASA Astrophysics Data System (ADS)
Stokes, A.
2017-02-01
The specification of microstates of interacting dynamical systems is different in Lagrangian and Hamiltonian approaches whenever the interaction Lagrangian depends on generalised velocities. In almost all cases of physical interest however, velocity-dependent interaction Lagrangians do not couple velocities belonging to different subsystems. For these cases we define reduced system and bath Lagrangian macrostates, which like the underlying microstates differ from their Hamiltonian counterparts. We then derive exact first and second laws of thermodynamics without any modification of the original system and bath quantities. This approach yields manifestly gauge-invariant definitions of work and free energy, and a gauge-invariant Jarzynski equality is derived. The formalism is applied in deriving the thermodynamic laws for a material system within the radiation reservoir. The Lagrangian partition of the total energy is manifestly gauge-invariant and is in accordance with Poynting's theorem.
Systems versus Classical Approach to Warfare
2009-01-01
events at others. In sequencing and synchronizing the use of military and non - military sources of power, operational com- manders must have the ability...approach, regardless of their differences, essen- tially share the mechanistic or Newtonian view of warfare. They believe that the information age...nonlinear.45 The Newtonian view of the world is that of a giant machine. Everything runs smoothly, precisely, and predictably. Everything is measurable.46
Classical mechanics approach applied to analysis of genetic oscillators.
Vasylchenkova, Anastasiia; Mraz, Miha; Zimic, Nikolaj; Moskon, Miha
2016-04-05
Biological oscillators present a fundamental part of several regulatory mechanisms that control the response of various biological systems. Several analytical approaches for their analysis have been reported recently. They are, however, limited to only specific oscillator topologies and/or to giving only qualitative answers, i.e., is the dynamics of an oscillator given the parameter space oscillatory or not. Here we present a general analytical approach that can be applied to the analysis of biological oscillators. It relies on the projection of biological systems to classical mechanics systems. The approach is able to provide us with relatively accurate results in the meaning of type of behaviour system reflects (i.e. oscillatory or not) and periods of potential oscillations without the necessity to conduct expensive numerical simulations. We demonstrate and verify the proposed approach on three different implementations of amplified negative feedback oscillator.
Path integral approach to electron scattering in classical electromagnetic potential
NASA Astrophysics Data System (ADS)
Chuang, Xu; Feng, Feng; Ying-Jun, Li
2016-05-01
As is known to all, the electron scattering in classical electromagnetic potential is one of the most widespread applications of quantum theory. Nevertheless, many discussions about electron scattering are based upon single-particle Schrodinger equation or Dirac equation in quantum mechanics rather than the method of quantum field theory. In this paper, by using the path integral approach of quantum field theory, we perturbatively evaluate the scattering amplitude up to the second order for the electron scattering by the classical electromagnetic potential. The results we derive are convenient to apply to all sorts of potential forms. Furthermore, by means of the obtained results, we give explicit calculations for the one-dimensional electric potential. Project supported by the National Natural Science Foundation of China (Grant Nos. 11374360, 11405266, and 11505285) and the National Basic Research Program of China (Grant No. 2013CBA01504).
Revisiting a Constructive Classic: Wright's Physical Disability: A Psychosocial Approach
Dunn, Dana S.; Elliott, Timothy R.
2008-01-01
Beatrice A. Wright's (1960) classic book, Physical Disability: A Psychological Approach is a landmark publication in rehabilitation psychology. The authors believe that Division 22's forthcoming 50th anniversary, the results of a recent survey on essential readings in rehabilitation psychology, and a public critique concerning the relevance of individuating language in psychology are compelling reasons for revisiting the influence of Physical Disability. After discussing these catalysts, the authors review the book's history, scholarly impact, and link to positive disciplinary directions. The authors conclude by encouraging rehabilitation psychologists and other members of the discipline to (re)acquaint themselves with this important book and the timeless concepts it espouses. PMID:19079791
Spinor dipolar bose-einstein condensates: classical spin approach.
Takahashi, M; Ghosh, Sankalpa; Mizushima, T; Machida, K
2007-06-29
Bose-Einstein condensates which are dominated by magnetic dipole-dipole interaction are discussed under spinful situations. We treat the spin degrees of freedom as a classical spin vector, approaching from the large spin limit to obtain an effective minimal Hamiltonian. This is a version extended from a nonlinear sigma model. By solving the Gross-Pitaevskii equation, we find several novel spin textures where the mass density and spin density are strongly coupled, depending upon trap geometries due to the long-range and anisotropic natures of the dipole-dipole interaction.
Spinor Dipolar Bose-Einstein Condensates: Classical Spin Approach
Takahashi, M.; Mizushima, T.; Machida, K.; Ghosh, Sankalpa
2007-06-29
Bose-Einstein condensates which are dominated by magnetic dipole-dipole interaction are discussed under spinful situations. We treat the spin degrees of freedom as a classical spin vector, approaching from the large spin limit to obtain an effective minimal Hamiltonian. This is a version extended from a nonlinear sigma model. By solving the Gross-Pitaevskii equation, we find several novel spin textures where the mass density and spin density are strongly coupled, depending upon trap geometries due to the long-range and anisotropic natures of the dipole-dipole interaction.
Interpersonal trust: An age-period-cohort analysis revisited.
Clark, April K; Eisenstein, Marie A
2013-03-01
Building on the previous work of Robinson and Jackson(1), this study addresses the extent to which interpersonal trust in America is changing due to age, period, or cohort effects (APC). The importance of APC in explaining variations in trust stems from the understanding that the specific source of change can have important - albeit different and possibly, negative - consequences on society. Moreover, 3years after the previous study concluded, the country experienced the largest concerted terrorist attacks on US soil. Little is known about how the attacks affected the dynamics of interpersonal trust relative to the processes of birth, aging, and historical change - such an investigation has important implications for our understanding of the sources and consequences of interpersonal trust. Two analysis techniques for disentangling APC effects are used: constrained generalized linear models and intrinsic estimator models. The results show that while period effects are an important contributor to declining trust, the attacks exert little influence over one's decision to trust others. Also, the investigation provides further confirmation that trust in others has fallen dramatically in the US with the scarcity being led by individuals coming of age in the late 1940s, after which, trust falls with each successive cohort. If this trend continues, through the process of cohort replacement, we will become a society of "distrusters".
Pulse-noise approach for classical spin systems
NASA Astrophysics Data System (ADS)
Garanin, D. A.
2017-01-01
For systems of classical spins interacting with the bath via damping and thermal noise, an approach is suggested to replace the white noise by a pulse noise acting at regular time intervals Δ t , within which the system evolves conservatively. The method is working well in the typical case of a small dimensionless damping constant λ and allows a considerable speedup of computations by using high-order numerical integrators with a large time step δ t (up to a fraction of the precession period), while keeping δ t ≪Δ t to reduce the relative contribution of noise-related operations. In cases when precession can be discarded, δ t can be increased up to a fraction of the relaxation time ∝1 /λ that leads to a further speedup. This makes equilibration speed comparable with that of the Metropolis Monte Carlo method. The pulse-noise approach is tested on single-spin and multispin models.
Pulse-noise approach for classical spin systems.
Garanin, D A
2017-01-01
For systems of classical spins interacting with the bath via damping and thermal noise, an approach is suggested to replace the white noise by a pulse noise acting at regular time intervals Δt, within which the system evolves conservatively. The method is working well in the typical case of a small dimensionless damping constant λ and allows a considerable speedup of computations by using high-order numerical integrators with a large time step δt (up to a fraction of the precession period), while keeping δt≪Δt to reduce the relative contribution of noise-related operations. In cases when precession can be discarded, δt can be increased up to a fraction of the relaxation time ∝1/λ that leads to a further speedup. This makes equilibration speed comparable with that of the Metropolis Monte Carlo method. The pulse-noise approach is tested on single-spin and multispin models.
A "Classic Papers" Approach to Teaching Undergraduate Organometallic Chemistry
NASA Astrophysics Data System (ADS)
Duncan, Andrew P.; Johnson, Adam R.
2007-03-01
We have structured an upper-level undergraduate course in organometallic chemistry on a selection of "classic" publications in the field. This approach offers students a richly contextual introduction to many of the fundamental tenets of the discipline. After a brief introduction to the field led by the faculty, the students themselves are responsible for researching and presenting selected papers to their classmates for analysis and discussion. Beyond mastery of basic organometallic principles, course goals for the students include improved proficiency in using the primary chemical literature and increased experience and confidence in researching, preparing, and delivering an informative oral presentation in individual and collaborative settings. Student performance is assessed based on performance on open-ended, take-home exams, quality of presentations, and contribution to in-class discussions. Student end-of-term survey responses indicate that this class model is successful as an introduction to organometallic chemistry.
Classical and Modern Approaches Used for Viral Hepatitis Diagnosis
Heiat, Mohammad; Ranjbar, Reza; Alavian, Seyed Moayed
2014-01-01
Context: Viral hepatitis diagnosis is an important issue in the treatment procedure of this infection. Late diagnosis and delayed treatment of viral hepatitis infections can lead to irreversible liver damages and occurrence of liver cirrhosis and hepatocellular carcinoma. A variety of laboratory methods including old and new technologies are being applied to detect hepatitis viruses. Here we have tried to review, categorize, compare and illustrate the classical and modern approaches used for diagnosis of viral hepatitis. Evidence Acquisition: In order to achieve a comprehensive aspect in viral hepatitis detection methods, an extensive search using related keywords was done in major medical library and data were collected, categorized and summarized in different sections. Results: Analyzing of collected data resulted in the wrapping up the hepatitis virus detection methods in separate sections including 1) immunological methods such as enzyme immunoassay (EIA), radio-immunoassay (RIA) immuno-chromatographic assay (ICA), and immuno-chemiluminescence 2) molecular approaches including non-amplification and amplification based methods, and finally 3) advanced biosensors such as mass-sensitive, electrical, electrochemical and optical based biosensors and also new generation of detection methods. Conclusions: Detection procedures in the clinical laboratories possess a large diversity; each has their individual advantages and facilities' differences. PMID:24829586
Phosphoproteomics by mass spectrometry and classical protein chemistry approaches.
Salih, Erdjan
2005-01-01
The general fields of biological sciences have seen phenomenal transformations in the past two decades at the level of data acquisition, understanding biological processes, and technological developments. Those advances have been made partly because of the advent of molecular biology techniques (which led to genomics) coupled to the advances made in mass spectrometry (MS) to provide the current capabilities and developments in proteomics. However, our current knowledge that approximately 30,000 human genes may code for up to 1 million or more proteins disengage the interface between the genome sequence database algorithms and MS to generate a major interest in independent de novo MS/MS sequence determination. Significant progress has been made in this area through procedures to covalently modify peptide N- and C-terminal amino-acids by sulfonation and guanidination to permit rapid de novo sequence determination by MS/MS analysis. A number of strategies that have been developed to perform qualitative and quantitative proteomics range from 2D-gel electrophoresis, affinity tag reagents, and stable-isotope labeling. Those procedures, combined with MS/MS peptide sequence analysis at the subpicomole level, permit the rapid and effective identification and quantification of a large number of proteins within a given biological sample. The identification of proteins per se, however, is not always sufficient to interpret biological function because many of the naturally occurring proteins are post-translationally modified. One such modification is protein phosphorylation, which regulates a large array of cellular biochemical pathways of the biological system. Traditionally, the study of phosphoprotein structure-function relationships involved classical protein chemistry approaches that required protein purification, peptide mapping, and the identification of the phosphorylated peptide regions and sites by N-terminal sequence analysis. Recent advances made in mass
Modern versus Tradition: Are There Two Different Approaches to Reading of the Confucian Classics?
ERIC Educational Resources Information Center
Cheng, Chung-yi
2016-01-01
How to read the Confucian Classics today? Scholars with philosophical training usually emphasize that the philosophical approach, in comparison with the classicist and historical ones, is the best way to read the Confucian Classics, for it can dig out as much intellectual resources as possible from the classical texts in order to show their modern…
Dynamic scaling at classical phase transitions approached through nonequilibrium quenching
NASA Astrophysics Data System (ADS)
Liu, Cheng-Wei; Polkovnikov, Anatoli; Sandvik, Anders W.
2014-02-01
We use Monte Carlo simulations to demonstrate generic scaling aspects of classical phase transitions approached through a quench (or annealing) protocol where the temperature changes as a function of time with velocity v. Using a generalized Kibble-Zurek ansatz, we demonstrate dynamic scaling for different types of stochastic dynamics (Metropolis, Swendsen-Wang, and Wolff) on Ising models in two and higher dimensions. We show that there are dual scaling functions governing the dynamic scaling, which together describe the scaling behavior in the entire velocity range v ∈[0,∞). These functions have asymptotics corresponding to the adiabatic and diabatic limits, and close to these limits they are perturbative in v and 1/v, respectively. Away from their perturbative domains, both functions cross over into the same universal power-law scaling form governed by the static and dynamic critical exponents (as well as an exponent characterizing the quench protocol). As a by-product of the scaling studies, we obtain high-precision estimates of the dynamic exponent z for the two-dimensional Ising model subject to the three variants of Monte Carlo dynamics: for single-spin Metropolis updates zM=2.1767(5), for Swendsen-Wang multicluster updates zSW=0.297(3), and for Wolff single-cluster updates zW=0.30(2). For Wolff dynamics, we find an interesting behavior with a nonanalytic breakdown of the quasiadiabatic and diabatic scalings, instead of the generic smooth crossover described by a power law. We interpret this disconnect between the two scaling regimes as a dynamic phase transition of the Wolff algorithm, caused by an effective sudden loss of ergodicity at high velocity.
An Approach to Bridging Classical and Modern Drama
ERIC Educational Resources Information Center
Levitt, Paul M.
1973-01-01
Employing Oedipus Rex'' and The Birthday Party'' as examples, the author demonstrates that literary criticism should give careful attention to parallels in format and content in the study of classical and modern drama. (RB)
Laban Movement Analysis Approach to Classical Ballet Pedagogy
ERIC Educational Resources Information Center
Whittier, Cadence
2006-01-01
As a Certified Laban Movement Analyst and a classically trained ballet dancer, I consistently weave the Laban Movement Analysis/Bartenieff Fundamentals (LMA/BF) theories and philosophies into the ballet class. This integration assists in: (1) Identifying the qualitative movement elements both in the art of ballet and in the students' dancing…
A Synthetic Approach to the Transfer Matrix Method in Classical and Quantum Physics
ERIC Educational Resources Information Center
Pujol, O.; Perez, J. P.
2007-01-01
The aim of this paper is to propose a synthetic approach to the transfer matrix method in classical and quantum physics. This method is an efficient tool to deal with complicated physical systems of practical importance in geometrical light or charged particle optics, classical electronics, mechanics, electromagnetics and quantum physics. Teaching…
Guanidines: from classical approaches to efficient catalytic syntheses.
Alonso-Moreno, Carlos; Antiñolo, Antonio; Carrillo-Hermosilla, Fernando; Otero, Antonio
2014-05-21
From organosuperbases capable of base-catalyzing organic reactions, through versatile 'ligand-sets' for use in coordination chemistry, to fundamental entities in medicinal chemistry, guanidines are amongst the most interesting, attractive, valuable, and versatile organic molecules. Since the discovery of these compounds, synthetic chemists have developed new methodologies that are mainly based on multi-step and stoichiometric reactions. Despite the fact that these methodologies are still being used by the interested scientific and industrial communities, drawbacks such as the poor availability of precursors, low yields, and use and production of undesirable substances highlight the need for safe, simple and efficient syntheses of these entities. This review focuses on the metal-mediated catalytic addition of amines to carbodiimides as an atom-economical alternative to the classical synthesis.
Complex network approach to classifying classical piano compositions
NASA Astrophysics Data System (ADS)
Xin, Chen; Zhang, Huishu; Huang, Jiping
2016-10-01
Complex network has been regarded as a useful tool handling systems with vague interactions. Hence, numerous applications have arised. In this paper we construct complex networks for 770 classical piano compositions of Mozart, Beethoven and Chopin based on musical note pitches and lengths. We find prominent distinctions among network edges of different composers. Some stylized facts can be explained by such parameters of network structures and topologies. Further, we propose two classification methods for music styles and genres according to the discovered distinctions. These methods are easy to implement and the results are sound. This work suggests that complex network could be a decent way to analyze the characteristics of musical notes, since it could provide a deep view into understanding of the relationships among notes in musical compositions and evidence for classification of different composers, styles and genres of music.
Comparison of Classical and Lazy Approach in SCG Compiler
NASA Astrophysics Data System (ADS)
Jirák, Ota; Kolář, Dušan
2011-09-01
The existing parsing methods of scattered context grammar usually expand nonterminals deeply in the pushdown. This expansion is implemented by using either a linked list, or some kind of an auxiliary pushdown. This paper describes the parsing algorithm of an LL(1) scattered context grammar. The given algorithm merges two principles together. The first approach is a table-driven parsing method commonly used for parsing of the context-free grammars. The second is a delayed execution used in functional programming. The main part of this paper is a proof of equivalence between the common principle (the whole rule is applied at once) and our approach (execution of the rules is delayed). Therefore, this approach works with the pushdown top only. In the most cases, the second approach is faster than the first one. Finally, the future work is discussed.
Sum Rules, Classical and Quantum - A Pedagogical Approach
NASA Astrophysics Data System (ADS)
Karstens, William; Smith, David Y.
2014-03-01
Sum rules in the form of integrals over the response of a system to an external probe provide general analytical tools for both experiment and theory. For example, the celebrated f-sum rule gives a system's plasma frequency as an integral over the optical-dipole absorption spectrum regardless of the specific spectral distribution. Moreover, this rule underlies Smakula's equation for the number density of absorbers in a sample in terms of the area under their absorption bands. Commonly such rules are derived from quantum-mechanical commutation relations, but many are fundamentally classical (independent of ℏ) and so can be derived from more transparent mechanical models. We have exploited this to illustrate the fundamental role of inertia in the case of optical sum rules. Similar considerations apply to sum rules in many other branches of physics. Thus, the ``attenuation integral theorems'' of ac circuit theory reflect the ``inertial'' effect of Lenz's Law in inductors or the potential energy ``storage'' in capacitors. These considerations are closely related to the fact that the real and imaginary parts of a response function cannot be specified independently, a result that is encapsulated in the Kramers-Kronig relations. Supported in part by the US Department of Energy, Office of Nuclear Physics under contract DE-AC02-06CH11357.
Classic and contemporary approaches to modeling biochemical reactions
Chen, William W.; Niepel, Mario; Sorger, Peter K.
2010-01-01
Recent interest in modeling biochemical networks raises questions about the relationship between often complex mathematical models and familiar arithmetic concepts from classical enzymology, and also about connections between modeling and experimental data. This review addresses both topics by familiarizing readers with key concepts (and terminology) in the construction, validation, and application of deterministic biochemical models, with particular emphasis on a simple enzyme-catalyzed reaction. Networks of coupled ordinary differential equations (ODEs) are the natural language for describing enzyme kinetics in a mass action approximation. We illustrate this point by showing how the familiar Briggs-Haldane formulation of Michaelis-Menten kinetics derives from the outer (or quasi-steady-state) solution of a dynamical system of ODEs describing a simple reaction under special conditions. We discuss how parameters in the Michaelis-Menten approximation and in the underlying ODE network can be estimated from experimental data, with a special emphasis on the origins of uncertainty. Finally, we extrapolate from a simple reaction to complex models of multiprotein biochemical networks. The concepts described in this review, hitherto of interest primarily to practitioners, are likely to become important for a much broader community of cellular and molecular biologists attempting to understand the promise and challenges of “systems biology” as applied to biochemical mechanisms. PMID:20810646
A biplex approach to PageRank centrality: From classic to multiplex networks.
Pedroche, Francisco; Romance, Miguel; Criado, Regino
2016-06-01
In this paper, we present a new view of the PageRank algorithm inspired by multiplex networks. This new approach allows to introduce a new centrality measure for classic complex networks and a new proposal to extend the usual PageRank algorithm to multiplex networks. We give some analytical relations between these new approaches and the classic PageRank centrality measure, and we illustrate the new parameters presented by computing them on real underground networks.
A classical approach to the graph isomorphism problem using quantum walks
NASA Astrophysics Data System (ADS)
Douglas, Brendan L.; Wang, Jingbo B.
2008-02-01
Given the extensive application of classical random walks to classical algorithms in a variety of fields, their quantum analogue in quantum walks is expected to provide a fruitful source of quantum algorithms. So far, however, such algorithms have been scarce. In this work, we enumerate some important differences between quantum and classical walks, leading to their markedly different properties. We show that for many practical purposes, the implementation of quantum walks can be efficiently achieved using a classical computer. We then develop both classical and quantum graph isomorphism algorithms based on discrete-time quantum walks. We show that they are effective in identifying isomorphism classes of large databases of graphs, in particular groups of strongly regular graphs. We consider this approach to represent a promising candidate for an efficient solution to the graph isomorphism problem, and believe that similar methods employing quantum walks, or derivatives of these walks, may prove beneficial in constructing other algorithms for a variety of purposes.
General approach to quantum-classical hybrid systems and geometric forces.
Zhang, Qi; Wu, Biao
2006-11-10
We present a general theoretical framework for a hybrid system that is composed of a quantum subsystem and a classical subsystem. We approach such a system with a simple canonical transformation which is particularly effective when the quantum subsystem is dynamically much faster than the classical counterpart, which is commonly the case in hybrid systems. Moreover, this canonical transformation generates a vector potential which, on one hand, gives rise to the familiar Berry phase in the fast quantum dynamics and, on the other hand, yields a Lorentz-like geometric force in the slow classical dynamics.
1982-05-15
Data MM—*0 REPORT DOCUMENTATION PAGE f REPORT NUMBER T-465 a. OOVT ACCESSION NO 4. TITLE Cnd SuMlla) CLASSICAL AND BAYSIAN APPROACHES TO...IS. KEY WOROS (Contlmtm on nr«H •!*• II nxmmmmr mit immMr *r NMt • CHANGE POINT, BAYSIAN SEQUENTIAL DETECTION, SURVEY PAPER SO. ABSTRACT
Approaches to Leadership: Some Classic Examples and Recent Theory for Experiential Educators.
ERIC Educational Resources Information Center
Robinson, Tom
Using three classic heroes of literature to examine different approaches to leadership, this paper describes the leadership style of each character and then describes a modern counterpart to each style; each of the modern leaders is an educator and facilitator of experiential learning. Cervantes' Don Quixote ("Don Quixote") is used as an example…
Jumbo-Lucioni, Patricia P; Garber, Kathryn; Kiel, John; Baric, Ivo; Berry, Gerard T; Bosch, Annet; Burlina, Alberto; Chiesa, Ana; Pico, Maria Luz Couce; Estrada, Sylvia C; Henderson, Howard; Leslie, Nancy; Longo, Nicola; Morris, Andrew A M; Ramirez-Farias, Carlett; Schweitzer-Krantz, Susanne; Scheweitzer-Krantz, Susanne; Silao, Catherine Lynn T; Vela-Amieva, Marcela; Waisbren, Susan; Fridovich-Keil, Judith L
2012-11-01
Without intervention, classic galactosemia is a potentially fatal disorder in infancy. With the benefit of early diagnosis and dietary restriction of galactose, the acute sequelae of classic galactosemia can be prevented or reversed. However, despite early and lifelong dietary treatment, many galactosemic patients go on to experience serious long-term complications including cognitive disability, speech problems, neurological and/or movement disorders and, in girls and women, ovarian dysfunction. Further, there remains uncertainty surrounding what constitutes a 'best practice' for treating this disorder. To explore the extent and implications of this uncertainty, we conducted a small but global survey of healthcare providers who follow patients with classic galactosemia, seeking to compare established protocols for diagnosis, intervention, and follow-up, as well as the outcomes and outcome frequencies seen in the patient populations cared for by these providers. We received 13 survey responses representing five continents and 11 countries. Respondents underscored disparities in approaches to diagnosis, management and follow-up care. Notably, we saw no clear relationship between differing approaches to care and long-term outcomes in the populations studied. Negative outcomes occurred in the majority of cases regardless of when treatment was initiated, how tightly galactose intake was restricted, or how closely patients were monitored. We document here what is, to our knowledge, the first global comparison of healthcare approaches to classic galactosemia. These data reinforce the idea that there is currently no one best practice for treating patients with classic galactosemia, and underscore the need for more extensive and statistically powerful comparative studies to reveal potential positive or negative impacts of differing approaches.
Wang, Qian; Hammes-Schiffer, Sharon
2006-11-14
A hybrid quantum/classical path integral Monte Carlo (QC-PIMC) method for calculating the quantum free energy barrier for hydrogen transfer reactions in condensed phases is presented. In this approach, the classical potential of mean force along a collective reaction coordinate is calculated using umbrella sampling techniques in conjunction with molecular dynamics trajectories propagated according to a mapping potential. The quantum contribution is determined for each configuration along the classical trajectory with path integral Monte Carlo calculations in which the beads move according to an effective mapping potential. This type of path integral calculation does not utilize the centroid constraint and can lead to more efficient sampling of the relevant region of conformational space than free-particle path integral sampling. The QC-PIMC method is computationally practical for large systems because the path integral sampling for the quantum nuclei is performed separately from the classical molecular dynamics sampling of the entire system. The utility of the QC-PIMC method is illustrated by an application to hydride transfer in the enzyme dihydrofolate reductase. A comparison of this method to the quantized classical path and grid-based methods for this system is presented.
Kandaswamy, Krishna Kumar; Pugalenthi, Ganesan; Hartmann, Enno; Kalies, Kai-Uwe; Moeller, Steffen; Suganthan, P.N.; Martinetz, Thomas
2010-01-15
Eukaryotic protein secretion generally occurs via the classical secretory pathway that traverses the ER and Golgi apparatus. Secreted proteins usually contain a signal sequence with all the essential information required to target them for secretion. However, some proteins like fibroblast growth factors (FGF-1, FGF-2), interleukins (IL-1 alpha, IL-1 beta), galectins and thioredoxin are exported by an alternative pathway. This is known as leaderless or non-classical secretion and works without a signal sequence. Most computational methods for the identification of secretory proteins use the signal peptide as indicator and are therefore not able to identify substrates of non-classical secretion. In this work, we report a random forest method, SPRED, to identify secretory proteins from protein sequences irrespective of N-terminal signal peptides, thus allowing also correct classification of non-classical secretory proteins. Training was performed on a dataset containing 600 extracellular proteins and 600 cytoplasmic and/or nuclear proteins. The algorithm was tested on 180 extracellular proteins and 1380 cytoplasmic and/or nuclear proteins. We obtained 85.92% accuracy from training and 82.18% accuracy from testing. Since SPRED does not use N-terminal signals, it can detect non-classical secreted proteins by filtering those secreted proteins with an N-terminal signal by using SignalP. SPRED predicted 15 out of 19 experimentally verified non-classical secretory proteins. By scanning the entire human proteome we identified 566 protein sequences potentially undergoing non-classical secretion. The dataset and standalone version of the SPRED software is available at (http://www.inb.uni-luebeck.de/tools-demos/spred/spred).
Approaches to define the viral genetic basis of classical swine fever virus virulence.
Leifer, Immanuel; Ruggli, Nicolas; Blome, Sandra
2013-04-10
Classical swine fever (CSF), a highly contagious disease of pigs caused by the classical swine fever virus (CSFV), can lead to important economic losses in the pig industry. Numerous CSFV isolates with various degrees of virulence have been isolated worldwide, ranging from low virulent strains that do not result in any apparent clinical signs to highly virulent strains that cause a severe peracute hemorrhagic fever with nearly 100% mortality. Knowledge of the molecular determinants of CSFV virulence is an important issue for effective disease control and development of safe and effective marker vaccines. In this review, the latest studies in the field of CSFV virulence are discussed. The topic of virulence is addressed from different angles; nonconventional approaches like codon pair usage and quasispecies are considered. Future research approaches in the field of CSFV virulence are proposed.
Shakib, Farnaz; Hanna, Gabriel
2016-07-12
In this work, we derive a general mixed quantum-classical formula for calculating thermal proton-coupled electron-transfer (PCET) rate constants, starting from the time integral of the quantum flux-flux correlation function. This formula allows for the direct simulation of PCET reaction dynamics via the mixed quantum-classical Liouville approach. Owing to the general nature of the derivation, this formula does not rely on any prior mechanistic assumptions and can be applied across a wide range of electronic and protonic coupling regimes. To test the validity of this formula, we applied it to a reduced model of a condensed-phase PCET reaction. Good agreement with the numerically exact rate constant is obtained, demonstrating the accuracy of our formalism. We believe that this approach constitutes a solid foundation for future investigations of the rates and mechanisms of a wide range of PCET reactions.
Semenov, Alexander; Babikov, Dmitri
2015-05-21
An efficient and accurate mixed quantum/classical theory approach for computational treatment of inelastic scattering is extended to describe collision of an atom with a general asymmetric-top rotor polyatomic molecule. Quantum mechanics, employed to describe transitions between the internal states of the molecule, and classical mechanics, employed for description of scattering of the atom, are used in a self-consistent manner. Such calculations for rotational excitation of HCOOCH3 in collisions with He produce accurate results at scattering energies above 15 cm(-1), although resonances near threshold, below 5 cm(-1), cannot be reproduced. Importantly, the method remains computationally affordable at high scattering energies (here up to 1000 cm(-1)), which enables calculations for larger molecules and at higher collision energies than was possible previously with the standard full-quantum approach. Theoretical prediction of inelastic cross sections for a number of complex organic molecules observed in space becomes feasible using this new computational tool.
Homogeneous nucleation: classical formulas as asymptotic limits of the Cahn-Hilliard approach.
Parra, I E; Cordero-Gracia, M; Gómez, M
2007-02-07
Classical expressions for the critical cluster work of formation approximate the nonclassical expressions based in the density functional theory of capillarity for the limit of low supersaturation degrees. However, the ratio between classical and nonclassical expressions for nucleation rates grows as the supersaturation degree decreases. Here, with the aim to obtain simple and more accurate expressions that approximate the modern nucleation rate formulas, an asymptotic expansion of the Cahn-Hilliard expression of the critical work of formation is developed within the limit of low supersaturation. In such asymptotic expansion, terms up to third order are retained. The ratios between the corrected classical expressions and the nonclassical ones are now decreasing for supersaturation degrees tending to zero. However, the corrected approximate formulas are as difficult to handle as the exact Cahn-Hilliard expressions. When only the two first low-order terms of the asymptotic expansion are retained, a simpler corrected classical expression is obtained but it can only approximate nonclassical expressions up to order unity. Finally, using a Becker-Doring model of nucleation, the kinetic prefactor of the critical nuclei rate of formation is modeled consistently with the Cahn-Hilliard approach to the critical work of formation.
A Monte Carlo Resampling Approach for the Calculation of Hybrid Classical and Quantum Free Energies.
Cave-Ayland, Christopher; Skylaris, Chris-Kriton; Essex, Jonathan W
2017-02-14
Hybrid free energy methods allow estimation of free energy differences at the quantum mechanics (QM) level with high efficiency by performing sampling at the classical mechanics (MM) level. Various approaches to allow the calculation of QM corrections to classical free energies have been proposed. The single step free energy perturbation approach starts with a classically generated ensemble, a subset of structures of which are postprocessed to obtain QM energies for use with the Zwanzig equation. This gives an estimate of the free energy difference associated with the change from an MM to a QM Hamiltonian. Owing to the poor numerical properties of the Zwanzig equation, however, recent developments have produced alternative methods which aim to provide access to the properties of the true QM ensemble. Here we propose an approach based on the resampling of MM structural ensembles and application of a Monte Carlo acceptance test which in principle, can generate the exact QM ensemble or intermediate ensembles between the MM and QM states. We carry out a detailed comparison against the Zwanzig equation and recently proposed non-Boltzmann methods. As a test system we use a set of small molecule hydration free energies for which hybrid free energy calculations are performed at the semiempirical Density Functional Tight Binding level. Equivalent ensembles at this level of theory have also been generated allowing the reverse QM to MM perturbations to be performed along with a detailed analysis of the results. Additionally, a previously published nucleotide base pair data set simulated at the QM level using ab initio molecular dynamics is also considered. We provide a strong rationale for the use of the Monte Carlo Resampling and non-Boltzmann approaches by showing that configuration space overlaps can be estimated which provide useful diagnostic information regarding the accuracy of these hybrid approaches.
Validity of the semi-classical approach for calculation of the surface excitation parameter.
Da, B; Mao, S F; Ding, Z J
2011-10-05
The problem of surface plasmon excitation by moving charges has been elaborated by several different approaches, mainly based on dielectric response theory within either semi-classical or quantum mechanical frameworks. In this work, a comparison of the surface excitation effect between two different frameworks is made by calculation of the differential inverse inelastic mean free path (DIIMFP) and a Monte Carlo simulation of reflection electron energy loss spectroscopy (REELS) spectra. A semi-classical modeling of the interaction between electrons and a solid surface is based on analyzing the work done by moving electrons; the stopping power and inelastic cross section are derived with the induced potential. On the other hand, a quantum mechanical approach is based on derivation of the complex inhomogeneous self-energy of the electrons. The numerical calculation shows that the semi-classical model presents almost the same values of DIIMFP as by the quantum model except at the glancing condition. The simulation of REELS spectra for Ag and SiO(2) as well as a comparison with experimental spectra also confirms that a good agreement with the spectral shape is found among the two simulation results and the experimental data.
Müller-Putz, G R; Schwarz, A; Pereira, J; Ofner, P
2016-01-01
In this chapter, we give an overview of the Graz-BCI research, from the classic motor imagery detection to complex movement intentions decoding. We start by describing the classic motor imagery approach, its application in tetraplegic end users, and the significant improvements achieved using coadaptive brain-computer interfaces (BCIs). These strategies have the drawback of not mirroring the way one plans a movement. To achieve a more natural control-and to reduce the training time-the movements decoded by the BCI need to be closely related to the user's intention. Within this natural control, we focus on the kinematic level, where movement direction and hand position or velocity can be decoded from noninvasive recordings. First, we review movement execution decoding studies, where we describe the decoding algorithms, their performance, and associated features. Second, we describe the major findings in movement imagination decoding, where we emphasize the importance of estimating the sources of the discriminative features. Third, we introduce movement target decoding, which could allow the determination of the target without knowing the exact movement-by-movement details. Aside from the kinematic level, we also address the goal level, which contains relevant information on the upcoming action. Focusing on hand-object interaction and action context dependency, we discuss the possible impact of some recent neurophysiological findings in the future of BCI control. Ideally, the goal and the kinematic decoding would allow an appropriate matching of the BCI to the end users' needs, overcoming the limitations of the classic motor imagery approach.
Mottin, Stephane; Panasenko, Grigory; Ganesh, S Sivaji
2010-12-31
In biophotonics, the light absorption in a tissue is usually modeled by the Helmholtz equation with two constant parameters, the scattering coefficient and the absorption coefficient. This classic approximation of "haemoglobin diluted everywhere" (constant absorption coefficient) corresponds to the classical homogenization approach. The paper discusses the limitations of this approach. The scattering coefficient is supposed to be constant (equal to one) while the absorption coefficient is equal to zero everywhere except for a periodic set of thin parallel strips simulating the blood vessels, where it is a large parameter ω. The problem contains two other parameters which are small: ε, the ratio of the distance between the axes of vessels to the characteristic macroscopic size, and δ, the ratio of the thickness of thin vessels and the period. We construct asymptotic expansion in two cases: ε --> 0, ω --> ∞, δ --> 0, ωδ --> ∞, ε2ωδ --> 0 and ε --> 0, ω --> ∞, δ --> 0, ε2ωδ --> ∞, and and prove that in the first case the classical homogenization (averaging) of the differential equation is true while in the second case it is wrong. This result may be applied in the biomedical optics, for instance, in the modeling of the skin and cosmetics.
[A non-classical approach to medical practices: Michel Foucault and Actor-Network Theory].
Bińczyk, E
2001-01-01
The text presents an analysis of medical practices stemming from two sources: Michel Foucault's conception and the research of Annemarie Mol and John Law, representatives of a trend known as Actor-Network Theory. Both approaches reveal significant theoretical kinship: they can be successfully consigned to the framework of non-classical sociology of science. I initially refer to the cited conceptions as a version of non-classical sociology of medicine. The identity of non-classical sociology of medicine hinges on the fact that it undermines the possibility of objective definitions of disease, health and body. These are rather approached as variable social and historical phenomena, co-constituted by medical practices. To both Foucault and Mol the main object of interest was not medicine as such, but rather the network of medical practices. Mol and Law sketch a new theoretical perspective for the analysis of medical practices. They attempt to go beyond the dichotomous scheme of thinking about the human body as an object of medical research and the subject of private experience. Research on patients suffering blood-sugar deficiency provide the empirical background for the thesis of Actor-Network Theory representatives. Michel Foucault's conceptions are extremely critical of medical practices. The French researcher describes the processes of 'medicalising' Western society as the emergence of a new type of power. He attempts to sensitise the reader to the ethical dimension of the processes of medicalising society.
NASA Astrophysics Data System (ADS)
Santos, F. A. N.; da Silva, L. C. B.; Coutinho-Filho, M. D.
2017-01-01
We propose a topological approach suitable to establish a connection between thermodynamics and topology in the microcanonical ensemble. Indeed, we report on results that point to the possibility of describing interacting classical spin systems in the thermodynamic limit, including the occurrence of a phase transition, using topological arguments only. Our approach relies on Morse theory, through the determination of the critical points of the potential energy, which is the proper Morse function. Our main finding is that, in the context of the classical models studied, the Euler characteristic χ (E) embeds the necessary features for a correct description of several magnetic thermodynamic quantities of the systems, such as the magnetization, correlation function, susceptibility, and critical temperature. Despite the classical nature of the models, such quantities are those that do not violate the laws of thermodynamics (with the proviso that van der Waals loop states are mean field (MF) artifacts). We also discuss the subtle connection between our approach using the Euler entropy, defined by the logarithm of the modulus of χ (E) per site, and that using the Boltzmann microcanonical entropy. Moreover, the results suggest that the loss of regularity in the Morse function is associated with the occurrence of unstable and metastable thermodynamic solutions in the MF case. The reliability of our approach is tested in two exactly soluble systems: the infinite-range and the one-dimensional short-range XY models in the presence of a magnetic field. In particular, we confirm that the topological hypothesis holds for both the infinite-range ({{T}c}\
Galitski, Victor
2011-07-15
We propose a Lie-algebraic duality approach to analyze nonequilibrium evolution of closed dynamical systems and thermodynamics of interacting quantum lattice models (formulated in terms of Hubbard-Stratonovich dynamical systems). The first part of the paper utilizes a geometric Hilbert-space-invariant formulation of unitary time evolution, where a quantum Hamiltonian is viewed as a trajectory in an abstract Lie algebra, while the sought-after evolution operator is a trajectory in a dynamic group, generated by the algebra via exponentiation. The evolution operator is uniquely determined by the time-dependent dual generators that satisfy a system of differential equations, dubbed here dual Schroedinger-Bloch equations, which represent a viable alternative to the conventional Schroedinger formulation. These dual Schroedinger-Bloch equations are derived and analyzed on a number of specific examples. It is shown that deterministic dynamics of a closed classical dynamical system occurs as action of a symmetry group on a classical manifold and is driven by the same dual generators as in the corresponding quantum problem. This represents quantum-to-classical correspondence. In the second part of the paper, we further extend the Lie-algebraic approach to a wide class of interacting many-particle lattice models. A generalized Hubbard-Stratonovich transform is proposed and it is used to show that the thermodynamic partition function of a generic many-body quantum lattice model can be expressed in terms of traces of single-particle evolution operators governed by the dynamic Hubbard-Stratonovich fields. The corresponding Hubbard-Stratonovich dynamical systems are generally nonunitary, which yields a number of notable complications, including breakdown of the global exponential representation. Finally, we derive Hubbard-Stratonovich dynamical systems for the Bose-Hubbard model and a quantum spin model and use the Lie-algebraic approach to obtain new nonperturbative dual
ERIC Educational Resources Information Center
National Council of Teachers of English, Urbana, IL.
New approaches to the teaching of the classics are explored in this collection of articles written by high school, junior college, college, and university literature instructors. The seven articles in the first section of the book discuss linking the classics. Specific topics covered in the articles include using the works of William Golding as a…
Treatment of rheumatoid arthritis. New thoughts on the classic pyramid approach.
Schenkier, S; Golbus, J
1992-01-01
Treatment of rheumatoid arthritis can be quite challenging. Toxicity profiles of the various anti-inflammatory agents are often unacceptable, mainly because of gastrointestinal intolerance or bleeding. In addition, epidemiologic data suggest that rheumatoid arthritis is a disease with substantial morbidity and increased mortality. Consequently, newer trends in therapy involve earlier use of remittive agents as well as use of low-dose steroids. These modifications of the classic pyramid approach and the investigation of other methods may significantly influence the future of rheumatoid arthritis therapy and improve quality of life in those with the disease.
NASA Technical Reports Server (NTRS)
Bond, Wie
1991-01-01
The results of active control experiments performed for the Mini-Mast truss structure are presented. The primary research objectives were: (1) to develop active structural control concepts and/or techniques; (2) to verify the concept of robust non-minimum-phase compensation for a certain class of non-colocated structural control problems through ground experiments; (3) to verify a 'dipole' concept for persistent disturbance rejection control of flexible structures; and (4) to identify CSI (Control Structure Interaction) issues and areas of emphasis for the next generation of large flexible spacecraft. The classical SISO (Single Input and Single Output) control design approach was employed.
NASA Astrophysics Data System (ADS)
Guasch, Oriol; García, Carlos; Jové, Jordi; Artís, Pere
2013-05-01
Transmissibility functions have received renewed interest given the important role they play in operational modal analysis and operational transfer path analysis. However, transmissibilities can also be used in the framework of classical transmission path analysis. This avoids some of the problems associated to the latter, such as the measurement of operational loads, or the need to remove the active parts of the system to measure frequency response functions. The key of the transmissibility approach to classical transfer path analysis relies on the notion of direct or blocked transmissibilities, which can be computed from standard measurable transmissibilities. The response at any degree of freedom to a system external load can then be decomposed in terms of the remaining degrees of freedom responses and the system direct transmissibilities. Although the theory supporting this approach has been known for long, no experimental validation test has been reported to date. It is the purpose of this paper to provide such a test by applying the method to a simple mechanical system for which an analytical solution can be derived. For different configurations, it will be shown that direct transmissibilities computed from measured transmissibilities compare fairly well with analytical results. This opens the door to apply the method to more complex situations of practical interest with confidence.
Complementary approaches to diagnosing marine diseases: a union of the modern and the classic
Burge, Colleen A.; Friedman, Carolyn S.; Getchell, Rodman; House, Marcia; Mydlarz, Laura D.; Prager, Katherine C.; Renault, Tristan; Kiryu, Ikunari; Vega-Thurber, Rebecca
2016-01-01
Linking marine epizootics to a specific aetiology is notoriously difficult. Recent diagnostic successes show that marine disease diagnosis requires both modern, cutting-edge technology (e.g. metagenomics, quantitative real-time PCR) and more classic methods (e.g. transect surveys, histopathology and cell culture). Here, we discuss how this combination of traditional and modern approaches is necessary for rapid and accurate identification of marine diseases, and emphasize how sole reliance on any one technology or technique may lead disease investigations astray. We present diagnostic approaches at different scales, from the macro (environment, community, population and organismal scales) to the micro (tissue, organ, cell and genomic scales). We use disease case studies from a broad range of taxa to illustrate diagnostic successes from combining traditional and modern diagnostic methods. Finally, we recognize the need for increased capacity of centralized databases, networks, data repositories and contingency plans for diagnosis and management of marine disease. PMID:26880839
Modeling of delays in PKPD: classical approaches and a tutorial for delay differential equations.
Koch, Gilbert; Krzyzanski, Wojciech; Pérez-Ruixo, Juan Jose; Schropp, Johannes
2014-08-01
In pharmacokinetics/pharmacodynamics (PKPD) the measured response is often delayed relative to drug administration, individuals in a population have a certain lifespan until they maturate or the change of biomarkers does not immediately affects the primary endpoint. The classical approach in PKPD is to apply transit compartment models (TCM) based on ordinary differential equations to handle such delays. However, an alternative approach to deal with delays are delay differential equations (DDE). DDEs feature additional flexibility and properties, realize more complex dynamics and can complementary be used together with TCMs. We introduce several delay based PKPD models and investigate mathematical properties of general DDE based models, which serve as subunits in order to build larger PKPD models. Finally, we review current PKPD software with respect to the implementation of DDEs for PKPD analysis.
Complementary approaches to diagnosing marine diseases: a union of the modern and the classic
Burge, Colleen A.; Friedman, Carolyn S.; Getchell, Rodman G.; House, Marcia; Lafferty, Kevin D.; Mydlarz, Laura D.; Prager, Katherine C.; Sutherland, Kathryn P.; Renault, Tristan; Kiryu, Ikunari; Vega-Thurber, Rebecca
2016-01-01
Linking marine epizootics to a specific aetiology is notoriously difficult. Recent diagnostic successes show that marine disease diagnosis requires both modern, cutting-edge technology (e.g. metagenomics, quantitative real-time PCR) and more classic methods (e.g. transect surveys, histopathology and cell culture). Here, we discuss how this combination of traditional and modern approaches is necessary for rapid and accurate identification of marine diseases, and emphasize how sole reliance on any one technology or technique may lead disease investigations astray. We present diagnostic approaches at different scales, from the macro (environment, community, population and organismal scales) to the micro (tissue, organ, cell and genomic scales). We use disease case studies from a broad range of taxa to illustrate diagnostic successes from combining traditional and modern diagnostic methods. Finally, we recognize the need for increased capacity of centralized databases, networks, data repositories and contingency plans for diagnosis and management of marine disease.
NASA Astrophysics Data System (ADS)
Alam, Muhammad Ashraful; Khan, M. Ryyan
2016-10-01
Bifacial tandem cells promise to reduce three fundamental losses (i.e., above-bandgap, below bandgap, and the uncollected light between panels) inherent in classical single junction photovoltaic (PV) systems. The successive filtering of light through the bandgap cascade and the requirement of current continuity make optimization of tandem cells difficult and accessible only to numerical solution through computer modeling. The challenge is even more complicated for bifacial design. In this paper, we use an elegantly simple analytical approach to show that the essential physics of optimization is intuitively obvious, and deeply insightful results can be obtained with a few lines of algebra. This powerful approach reproduces, as special cases, all of the known results of conventional and bifacial tandem cells and highlights the asymptotic efficiency gain of these technologies.
Onisko, Agnieszka; Druzdzel, Marek J.; Austin, R. Marshall
2016-01-01
Background: Classical statistics is a well-established approach in the analysis of medical data. While the medical community seems to be familiar with the concept of a statistical analysis and its interpretation, the Bayesian approach, argued by many of its proponents to be superior to the classical frequentist approach, is still not well-recognized in the analysis of medical data. Aim: The goal of this study is to encourage data analysts to use the Bayesian approach, such as modeling with graphical probabilistic networks, as an insightful alternative to classical statistical analysis of medical data. Materials and Methods: This paper offers a comparison of two approaches to analysis of medical time series data: (1) classical statistical approach, such as the Kaplan–Meier estimator and the Cox proportional hazards regression model, and (2) dynamic Bayesian network modeling. Our comparison is based on time series cervical cancer screening data collected at Magee-Womens Hospital, University of Pittsburgh Medical Center over 10 years. Results: The main outcomes of our comparison are cervical cancer risk assessments produced by the three approaches. However, our analysis discusses also several aspects of the comparison, such as modeling assumptions, model building, dealing with incomplete data, individualized risk assessment, results interpretation, and model validation. Conclusion: Our study shows that the Bayesian approach is (1) much more flexible in terms of modeling effort, and (2) it offers an individualized risk assessment, which is more cumbersome for classical statistical approaches. PMID:28163973
Numerical study of chiral plasma instability within the classical statistical field theory approach
NASA Astrophysics Data System (ADS)
Buividovich, P. V.; Ulybyshev, M. V.
2016-07-01
We report on a numerical study of real-time dynamics of electromagnetically interacting chirally imbalanced lattice Dirac fermions within the classical statistical field theory approach. Namely, we perform exact simulations of the real-time quantum evolution of fermionic fields coupled to classical electromagnetic fields, which are in turn coupled to the vacuum expectation value of the fermionic electric current. We use Wilson-Dirac Hamiltonian for fermions, and noncompact action for the gauge field. In general, we observe that the backreaction of fermions on the electromagnetic field prevents the system from acquiring chirality imbalance. In the case of chirality pumping in parallel electric and magnetic fields, the electric field is screened by the produced on-shell fermions and the accumulation of chirality is hence stopped. In the case of evolution with initially present chirality imbalance, axial charge tends to transform to helicity of the electromagnetic field. By performing simulations on large lattices we show that in most cases this decay process is accompanied by the inverse cascade phenomenon, which transfers energy from short-wavelength to long-wavelength electromagnetic fields. In some simulations, however, we observe a very clear signature of inverse cascade for the helical magnetic fields that is not accompanied by the axial charge decay. This suggests that the relation between the inverse cascade and axial charge decay is not as straightforward as predicted by the simplest form of anomalous Maxwell equations.
The classical drug discovery approach to defining bioactive constituents of botanicals.
Kinghorn, A Douglas; Chai, Hee-byung; Sung, Chung Ki; Keller, William J
2011-01-01
In this review, several recently identified biologically active principles of selected botanical dietary supplement ingredients are described, and were isolated using classical phytochemical chromatographic methods, with various spectroscopic procedures used for their isolation and structure elucidation. A central component of such an approach is "activity-guided fractionation" to monitor the compound purification process. In vitro assays germane to cancer chemoprevention were used to facilitate the work performed. Bioactive compounds, including several new substances, were characterized from açai (Euterpe oleracea), baobab (Adansonia digitata), licorice (Glycyrrhiza glabra), mangosteen (Garcinia mangostana), and noni (Morinda citrifolia). Many of these compounds exhibited quite potent biological activity, but tended to be present in their plant of origin only at low concentration levels.
Non-Kolmogorovian Approach to the Context-Dependent Systems Breaking the Classical Probability Law
NASA Astrophysics Data System (ADS)
Asano, Masanari; Basieva, Irina; Khrennikov, Andrei; Ohya, Masanori; Yamato, Ichiro
2013-07-01
There exist several phenomena breaking the classical probability laws. The systems related to such phenomena are context-dependent, so that they are adaptive to other systems. In this paper, we present a new mathematical formalism to compute the joint probability distribution for two event-systems by using concepts of the adaptive dynamics and quantum information theory, e.g., quantum channels and liftings. In physics the basic example of the context-dependent phenomena is the famous double-slit experiment. Recently similar examples have been found in biological and psychological sciences. Our approach is an extension of traditional quantum probability theory, and it is general enough to describe aforementioned contextual phenomena outside of quantum physics.
A survey of existing and proposed classical and quantum approaches to the photon mass
NASA Astrophysics Data System (ADS)
Spavieri, G.; Quintero, J.; Gillies, G. T.; Rodríguez, M.
2011-02-01
Over the past twenty years, there have been several careful experimental, observational and phenomenological investigations aimed at searching for and establishing ever tighter bounds on the possible mass of the photon. There are many fascinating and paradoxical physical implications that would arise from the presence of even a very small value for it, and thus such searches have always been well motivated in terms of the new physics that would result. We provide a brief overview of the theoretical background and classical motivations for this work and the early tests of the exactness of Coulomb's law that underlie it. We then go on to address the modern situation, in which quantum physics approaches come to attention. Among them we focus especially on the implications that the Aharonov-Bohm and Aharonov-Casher class of effects have on searches for a photon mass. These arise in several different ways and can lead to experiments that might involve the interaction of magnetic dipoles, electric dipoles, or charged particles with suitable potentials. Still other quantum-based approaches employ measurements of the g-factor of the electron. Plausible target sensitivities for limits on the photon mass as sought by the various quantum approaches are in the range of 10-53 to 10-54 g. Possible experimental arrangements for the associated experiments are discussed. We close with an assessment of the state of the art and a prognosis for future work.
NASA Astrophysics Data System (ADS)
Mokshin, A. V.
2015-04-01
The concept of time correlation functions is a very convenient theoretical tool in describing relaxation processes in multiparticle systems because, on one hand, correlation functions are directly related to experimentally measured quantities (for example, intensities in spectroscopic studies and kinetic coefficients via the Kubo-Green relation) and, on the other hand, the concept is also applicable beyond the equilibrium case. We show that the formalism of memory functions and the method of recurrence relations allow formulating a self-consistent approach for describing relaxation processes in classical multiparticle systems without needing a priori approximations of time correlation functions by model dependences and with the satisfaction of sum rules and other physical conditions guaranteed. We also demonstrate that the approach can be used to treat the simplest relaxation scenarios and to develop microscopic theories of transport phenomena in liquids, the propagation of density fluctuations in equilibrium simple liquids, and structure relaxation in supercooled liquids. This approach generalizes the mode-coupling approximation in the Götze-Leutheusser realization and the Yulmetyev-Shurygin correlation approximations.
Lee, Sang-Bong
1993-09-01
Quantum manifestation of classical chaos has been one of the extensively studied subjects for more than a decade. Yet clear understanding of its nature still remains to be an open question partly due to the lack of a canonical definition of quantum chaos. The classical definition seems to be unsuitable in quantum mechanics partly because of the Heisenberg quantum uncertainty. In this regard, quantum chaos is somewhat misleading and needs to be clarified at the very fundamental level of physics. Since it is well known that quantum mechanics is more fundamental than classical mechanics, the quantum description of classically chaotic nature should be attainable in the limit of large quantum numbers. The focus of my research, therefore, lies on the correspondence principle for classically chaotic systems. The chaotic damped driven pendulum is mainly studied numerically using the split operator method that solves the time-dependent Schroedinger equation. For classically dissipative chaotic systems in which (multi)fractal strange attractors often emerge, several quantum dissipative mechanisms are also considered. For instance, Hoover`s and Kubo-Fox-Keizer`s approaches are studied with some computational analyses. But the notion of complex energy with non-Hermiticity is extensively applied. Moreover, the Wigner and Husimi distribution functions are examined with an equivalent classical distribution in phase-space, and dynamical properties of the wave packet in configuration and momentum spaces are also explored. The results indicate that quantum dynamics embraces classical dynamics although the classicalquantum correspondence fails to be observed in the classically chaotic regime. Even in the semi-classical limits, classically chaotic phenomena would eventually be suppressed by the quantum uncertainty.
Path-integral approach to 't Hooft's derivation of quantum physics from classical physics
Blasone, Massimo; Jizba, Petr; Kleinert, Hagen
2005-05-15
We present a path-integral formulation of 't Hooft's derivation of quantum physics from classical physics. The crucial ingredient of this formulation is Gozzi et al.'s supersymmetric path integral of classical mechanics. We quantize explicitly two simple classical systems: the planar mathematical pendulum and the Roessler dynamical system.
Materialism across the life span: An age-period-cohort analysis.
Jaspers, Esther D T; Pieters, Rik G M
2016-09-01
This research examined the development of materialism across the life span. Two initial studies revealed that (a) lay beliefs were that materialism declines with age and (b) previous research findings also implied a modest, negative relationship between age and materialism. Yet, previous research has considered age only as a linear control variable, thereby precluding the possibility of more intricate relationships between age and materialism. Moreover, prior studies have relied on cross-sectional data and thus confound age and cohort effects. To improve on this, the main study used longitudinal data from 8 waves spanning 9 years of over 4,200 individuals (16 to 90 years) to examine age effects on materialism while controlling for cohort and period effects. Using a multivariate multilevel latent growth model, it found that materialism followed a curvilinear trajectory across the life span, with the lowest levels at middle age and higher levels before and after that. Thus, in contrast to lay beliefs, materialism increased in older age. Moreover, age effects on materialism differed markedly between 3 core themes of materialism: acquisition centrality, possession-defined success, and acquisition as the pursuit of happiness. In particular, acquisition centrality and possession-defined success were higher at younger and older age. Independent of these age effects, older birth cohorts were oriented more toward possession-defined success, whereas younger birth cohorts were oriented more toward acquisition centrality. The economic downturn since 2008 led to a decrease in acquisition as the pursuit of happiness and in desires for personal growth, but to an increase in desires for achievement. (PsycINFO Database Record
Increasing incidence of thyroid cancer in Great Britain, 1976-2005: age-period-cohort analysis.
McNally, Richard J Q; Blakey, Karen; James, Peter W; Gomez Pozo, Basilio; Basta, Nermine O; Hale, Juliet
2012-08-01
Increases in the incidence of thyroid cancer have been previously reported. The purpose of the present study was to examine temporal trends in the incidence of primary thyroid cancer diagnosed in 0-49 year olds in parts of Great Britain during 1976-2005. Data on 4,337 cases of thyroid cancer were obtained from regional cancer registries. Age-standardized incidence rates (ASRs) were calculated. Negative binomial regression was used to examine effects of age, sex, drift (linear trend), non-linear period and non-linear cohort. The best fitting negative binomial regression model included age (P < 0.001), sex (P < 0.001) and drift (P < 0.001). Non-linear period (P = 0.648) and non-linear cohort (P = 0.788) were not statistically significant. For males aged 0-14, the ASR increased from 0.2 per million persons per year in 1976-1986 to 0.6 in 1997-2005. For males aged 15-29 and 30-49 the ASRs increased from 1.9 to 3.3 and from 7.4 to 12.7, respectively. For females aged 0-14, the corresponding ASR increased from 0.3 to 0.5. For females aged 15-29 and 30-49 the ASRs increased from 6.9 to 12.4 and from 21.2 to 42.3, respectively. For all age groups, there has been a linear increase in incidence of thyroid cancer, which has led to a doubling of the number of cases diagnosed over a twenty year span. The reasons for this increase are not well understood, but it is consistent with findings from other countries.
Classical convergence versus Zipf rank approach: Evidence from China's local-level data
NASA Astrophysics Data System (ADS)
Tang, Pan; Zhang, Ying; Baaquie, Belal E.; Podobnik, Boris
2016-02-01
This paper applies Zipf rank approach to measure how long it will take for the individual economy to reach the final state of equilibrium by using local-level data of China's urban areas. The indicators, the gross domestic product (GDP) per capita and the market capitalization (MCAP) per capita of 150 major cities in China are used for analyzing their convergence. Besides, the power law relationship is examined for GDP and MCAP. Our findings show that, compared to the classical approaches: β-convergence and σ-convergence, the Zipf ranking predicts that, in approximately 16 years, all the major cities in China will reach comparable values of GDP per capita. However, the MCAP per capita tends to follow the periodic fluctuation of the economic cycle, while the mean-log derivation (MLD) confirms the results of our study. Moreover, GDP per capita and MCAP per capita follow a power law with an average value of α = 0.41 which is higher than α = 0.38 obtained based on a large number of countries around the world.
NASA Technical Reports Server (NTRS)
Tsue, Yasuhiko
1994-01-01
A general framework for time-dependent variational approach in terms of squeezed coherent states is constructed with the aim of describing quantal systems by means of classical mechanics including higher order quantal effects with the aid of canonicity conditions developed in the time-dependent Hartree-Fock theory. The Maslov phase occurring in a semi-classical quantization rule is investigated in this framework. In the limit of a semi-classical approximation in this approach, it is definitely shown that the Maslov phase has a geometric nature analogous to the Berry phase. It is also indicated that this squeezed coherent state approach is a possible way to go beyond the usual WKB approximation.
Pelzer, Kenley M.; Vázquez-Mayagoitia, Álvaro; Ratcliff, Laura E.; ...
2017-01-01
Organic photovoltaics (OPVs) are a promising carbon-neutral energy conversion technology, with recent improvements pushing power conversion efficiencies over 10%. A major factor limiting OPV performance is inefficiency of charge transport in organic semiconducting materials (OSCs). Due to strong coupling with lattice degrees of freedom, the charges form polarons, localized quasi-particles comprised of charges dressed with phonons. These polarons can be conceptualized as pseudo-atoms with a greater effective mass than a bare charge. Here we propose that due to this increased mass, polarons can be modeled with Langevin molecular dynamics (LMD), a classical approach with a computational cost much lower thanmore » most quantum mechanical methods. Here we present LMD simulations of charge transfer between a pair of fullerene molecules, which commonly serve as electron acceptors in OSCs. We find transfer rates consistent with experimental measurements of charge mobility, suggesting that this method may provide quantitative predictions of efficiency when used to simulate materials on the device scale. Our approach also offers information that is not captured in the overall transfer rate or mobility: in the simulation data, we observe exactly when and why intermolecular transfer events occur. In addition, we demonstrate that these simulations can shed light on the properties of polarons in OSCs. In conclusion, much remains to be learned about these quasi-particles, and there are no widely accepted methods for calculating properties such as effective mass and friction. Lastly, our model offers a promising approach to exploring mass and friction as well as providing insight into the details of polaron transport in OSCs.« less
Pelzer, Kenley M.; Vázquez-Mayagoitia, Álvaro; Ratcliff, Laura E.; Tretiak, Sergei; Bair, Raymond A.; Gray, Stephen K.; Van Voorhis, Troy; Larsen, Ross E.; Darling, Seth B.
2017-01-01
Organic photovoltaics (OPVs) are a promising carbon-neutral energy conversion technology, with recent improvements pushing power conversion efficiencies over 10%. A major factor limiting OPV performance is inefficiency of charge transport in organic semiconducting materials (OSCs). Due to strong coupling with lattice degrees of freedom, the charges form polarons, localized quasi-particles comprised of charges dressed with phonons. These polarons can be conceptualized as pseudo-atoms with a greater effective mass than a bare charge. Here we propose that due to this increased mass, polarons can be modeled with Langevin molecular dynamics (LMD), a classical approach with a computational cost much lower than most quantum mechanical methods. Here we present LMD simulations of charge transfer between a pair of fullerene molecules, which commonly serve as electron acceptors in OSCs. We find transfer rates consistent with experimental measurements of charge mobility, suggesting that this method may provide quantitative predictions of efficiency when used to simulate materials on the device scale. Our approach also offers information that is not captured in the overall transfer rate or mobility: in the simulation data, we observe exactly when and why intermolecular transfer events occur. In addition, we demonstrate that these simulations can shed light on the properties of polarons in OSCs. In conclusion, much remains to be learned about these quasi-particles, and there are no widely accepted methods for calculating properties such as effective mass and friction. Lastly, our model offers a promising approach to exploring mass and friction as well as providing insight into the details of polaron transport in OSCs.
Schmiedt, Hanno; Schlemmer, Stephan; Yurchenko, Sergey N; Yachmenev, Andrey; Jensen, Per
2017-01-18
We report a new semi-classical method to compute highly excited rotational energy levels of an asymmetric-top molecule. The method forgoes the idea of a full quantum mechanical treatment of the ro-vibrational motion of the molecule. Instead, it employs a semi-classical Green's function approach to describe the rotational motion, while retaining a quantum mechanical description of the vibrations. Similar approaches have existed for some time, but the method proposed here has two novel features. First, inspired by the path integral method, periodic orbits in the phase space and tunneling paths are naturally obtained by means of molecular symmetry analysis. Second, the rigorous variational method is employed for the first time to describe the molecular vibrations. In addition, we present a new robust approach to generating rotational energy surfaces for vibrationally excited states; this is done in a fully quantum-mechanical, variational manner. The semi-classical approach of the present work is applied to calculating the energies of very highly excited rotational states and it reduces dramatically the computing time as well as the storage and memory requirements when compared to the fullly quantum-mechanical variational approach. Test calculations for excited states of SO2 yield semi-classical energies in very good agreement with the available experimental data and the results of fully quantum-mechanical calculations.
Schmiedt, Hanno; Schlemmer, Stephan; Yurchenko, Sergey N.; Yachmenev, Andrey
2017-01-01
We report a new semi-classical method to compute highly excited rotational energy levels of an asymmetric-top molecule. The method forgoes the idea of a full quantum mechanical treatment of the ro-vibrational motion of the molecule. Instead, it employs a semi-classical Green's function approach to describe the rotational motion, while retaining a quantum mechanical description of the vibrations. Similar approaches have existed for some time, but the method proposed here has two novel features. First, inspired by the path integral method, periodic orbits in the phase space and tunneling paths are naturally obtained by means of molecular symmetry analysis. Second, the rigorous variational method is employed for the first time to describe the molecular vibrations. In addition, we present a new robust approach to generating rotational energy surfaces for vibrationally excited states; this is done in a fully quantum-mechanical, variational manner. The semi-classical approach of the present work is applied to calculating the energies of very highly excited rotational states and it reduces dramatically the computing time as well as the storage and memory requirements when compared to the fullly quantum-mechanical variational approach. Test calculations for excited states of SO2 yield semi-classical energies in very good agreement with the available experimental data and the results of fully quantum-mechanical calculations. PMID:28000807
General Approach to Quantum Channel Impossibility by Local Operations and Classical Communication
NASA Astrophysics Data System (ADS)
Cohen, Scott M.
2017-01-01
We describe a general approach to proving the impossibility of implementing a quantum channel by local operations and classical communication (LOCC), even with an infinite number of rounds, and find that this can often be demonstrated by solving a set of linear equations. The method also allows one to design a LOCC protocol to implement the channel whenever such a protocol exists in any finite number of rounds. Perhaps surprisingly, the computational expense for analyzing LOCC channels is not much greater than that for LOCC measurements. We apply the method to several examples, two of which provide numerical evidence that the set of quantum channels that are not LOCC is not closed and that there exist channels that can be implemented by LOCC either in one round or in three rounds that are on the boundary of the set of all LOCC channels. Although every LOCC protocol must implement a separable quantum channel, it is a very difficult task to determine whether or not a given channel is separable. Fortunately, prior knowledge that the channel is separable is not required for application of our method.
Stott, Clifford; Drury, John
2016-04-01
This article explores the origins and ideology of classical crowd psychology, a body of theory reflected in contemporary popularised understandings such as of the 2011 English 'riots'. This article argues that during the nineteenth century, the crowd came to symbolise a fear of 'mass society' and that 'classical' crowd psychology was a product of these fears. Classical crowd psychology pathologised, reified and decontextualised the crowd, offering the ruling elites a perceived opportunity to control it. We contend that classical theory misrepresents crowd psychology and survives in contemporary understanding because it is ideological. We conclude by discussing how classical theory has been supplanted in academic contexts by an identity-based crowd psychology that restores the meaning to crowd action, replaces it in its social context and in so doing transforms theoretical understanding of 'riots' and the nature of the self.
ERIC Educational Resources Information Center
Wilson, Mark; Allen, Diane D.; Li, Jun Corser
2006-01-01
This paper compares the approach and resultant outcomes of item response models (IRMs) and classical test theory (CTT). First, it reviews basic ideas of CTT, and compares them to the ideas about using IRMs introduced in an earlier paper. It then applies a comparison scheme based on the AERA/APA/NCME "Standards for Educational and…
ERIC Educational Resources Information Center
García, Nuria Alonso; Caplan, Alison
2014-01-01
While there are a number of important critical pedagogies being proposed in the field of foreign language study, more attention should be given to providing concrete examples of how to apply these ideas in the classroom. This article offers a new approach to the textual analysis of literary classics through the keyword-based methodology originally…
Dynamically consistent method for mixed quantum-classical simulations: A semiclassical approach.
Antipov, Sergey V; Ye, Ziyu; Ananth, Nandini
2015-05-14
We introduce a new semiclassical (SC) framework, the Mixed Quantum-Classical Initial Value Representation (MQC-IVR), that can be tuned to reproduce existing quantum-limit and classical-limit SC approximations to quantum real-time correlation functions. Applying a modified Filinov transformation to a quantum-limit SC formulation leads to the association of a Filinov parameter with each degree of freedom in the system; varying this parameter from zero to infinity controls the extent of quantization of the corresponding mode. The resulting MQC-IVR expression provides a consistent dynamic framework for mixed quantum-classical simulations and we demonstrate its numerical accuracy in the calculation of real-time correlation functions for a model 1D system and a model 2D system over the full range of quantum- to classical-limit behaviors.
Dynamically consistent method for mixed quantum-classical simulations: A semiclassical approach
Antipov, Sergey V.; Ye, Ziyu; Ananth, Nandini
2015-05-14
We introduce a new semiclassical (SC) framework, the Mixed Quantum-Classical Initial Value Representation (MQC-IVR), that can be tuned to reproduce existing quantum-limit and classical-limit SC approximations to quantum real-time correlation functions. Applying a modified Filinov transformation to a quantum-limit SC formulation leads to the association of a Filinov parameter with each degree of freedom in the system; varying this parameter from zero to infinity controls the extent of quantization of the corresponding mode. The resulting MQC-IVR expression provides a consistent dynamic framework for mixed quantum-classical simulations and we demonstrate its numerical accuracy in the calculation of real-time correlation functions for a model 1D system and a model 2D system over the full range of quantum- to classical-limit behaviors.
Teaching Statistics Using Classic Psychology Research: An Activities-Based Approach
ERIC Educational Resources Information Center
Holmes, Karen Y.; Dodd, Brett A.
2012-01-01
In this article, we discuss a collection of active learning activities derived from classic psychology studies that illustrate the appropriate use of descriptive and inferential statistics. (Contains 2 tables.)
Extended hydrodynamic approach to quantum-classical nonequilibrium evolution. I. Theory.
Bousquet, David; Hughes, Keith H; Micha, David A; Burghardt, Irene
2011-02-14
A mixed quantum-classical formulation is developed for a quantum subsystem in strong interaction with an N-particle environment, to be treated as classical in the framework of a hydrodynamic representation. Starting from the quantum Liouville equation for the N-particle distribution and the corresponding reduced single-particle distribution, exact quantum hydrodynamic equations are obtained for the momentum moments of the single-particle distribution coupled to a discretized quantum subsystem. The quantum-classical limit is subsequently taken and the resulting hierarchy of equations is further approximated by various closure schemes. These include, in particular, (i) a Grad-Hermite-type closure, (ii) a Gaussian closure at the level of a quantum-classical local Maxwellian distribution, and (iii) a dynamical density functional theory approximation by which the hydrodynamic pressure term is replaced by a free energy functional derivative. The latter limit yields a mixed quantum-classical formulation which has previously been introduced by I. Burghardt and B. Bagchi, Chem. Phys. 134, 343 (2006).
The Bread and Butter of Classical Organizational Approaches: The Time-and-Motion Study
ERIC Educational Resources Information Center
Peterson, Dan W.
2007-01-01
The thought of learning about the principles of classical management and the machine metaphor of organizing can get many organizational communication students yawning just by seeing the subject in a syllabus. Abundant movie and television examples associated with the machine-like nature of workplace productivity are often used to demonstrate…
A unified approach to quantum and classical TTW systems based on factorizations
Celeghini, E.; Kuru, Ş.; Negro, J.; Olmo, M.A. del
2013-05-15
A unifying method based on factorization properties is introduced for finding symmetries of quantum and classical superintegrable systems using the example of the Tremblay–Turbiner–Winternitz (TTW) model. It is shown that the symmetries of the quantum system can be implemented in a natural way to its classical version. Besides, by this procedure we get also other type of constants of motion depending explicitly on time that allow to find directly the motion of the system whose corresponding trajectories coincide with those obtained previously by using its symmetries. -- Highlights: ► A unified method is given to find symmetries of classical and quantum systems. ► Ladder–shift operators and functions have analog expressions and relations. ► This method is applied to the TTW system to obtain its symmetries. ► For the classical cases a set of time dependent constants of motion are obtained. ► They allow us to find directly the motion and trajectories.
Quantum-classical correspondences for atomic operators: a positive P representation approach
NASA Astrophysics Data System (ADS)
You, L.; Cooper, J.; Zoller, P.
1995-10-01
We demonstrate the successful simulation of classical stochastic differential equations obtained from the positive P phase-space technique for two-level atoms pumped by a near-resonant laser. Numerical results for both the resonance fluorescence spectrum and the absorption spectrum are compared with the exact results. Copyright (c) 1995 Optical Society of America
Applying molecular-based approaches to classical biological control of weeds
Technology Transfer Automated Retrieval System (TEKTRAN)
Modern advances in molecular techniques are only recently being incorporated into programs for the classical biological control of weeds. Molecular analyses are able to elucidate information about target weeds that is critical to improving control success, such as taxonomic clarification, evidence o...
John Stirling and the Classical Approach to Style in 18th Century England.
ERIC Educational Resources Information Center
Moran, Michael G.
Most 18th-century rhetoricians viewed style as the expression of a writer's individual character and thought, placing little emphasis on the lists of figures common in many 17th-century rhetorics. John Stirling and others, however, continued the 17th-century tradition that reduced rhetoric largely to style and emphasized classical figures of…
Semi-classical approach to compute RABBITT traces in multi-dimensional complex field distributions.
Lucchini, M; Ludwig, A; Kasmi, L; Gallmann, L; Keller, U
2015-04-06
We present a semi-classical model to calculate RABBITT (Reconstruction of Attosecond Beating By Interference of Two-photon Transitions) traces in the presence of a reference infrared field with a complex two-dimensional (2D) spatial distribution. The evolution of the electron spectra as a function of the pump-probe delay is evaluated starting from the solution of the classical equation of motion and incorporating the quantum phase acquired by the electron during the interaction with the infrared field. The total response to an attosecond pulse train is then evaluated by a coherent sum of the contributions generated by each individual attosecond pulse in the train. The flexibility of this model makes it possible to calculate spectrograms from non-trivial 2D field distributions. After confirming the validity of the model in a simple 1D case, we extend the discussion to describe the probe-induced phase in photo-emission experiments on an ideal metallic surface.
NASA Astrophysics Data System (ADS)
McMillan, Ryan J.; Stella, Lorenzo; Grüning, Myrta
2016-09-01
We introduce a hybrid method for dielectric-metal composites that describes the dynamics of the metallic system classically while retaining a quantum description of the dielectric. The time-dependent dipole moment of the classical system is mimicked by the introduction of projected equations of motion (PEOM), and the coupling between the two systems is achieved through an effective dipole-dipole interaction. To benchmark this method, we model a test system (semiconducting quantum dot-metal nanoparticle hybrid). We begin by examining the energy absorption rate, showing agreement between the PEOM method and the analytical rotating wave approximation (RWA) solution. We then investigate population inversion and show that the PEOM method provides an accurate model for the interaction under ultrashort pulse excitation where the traditional RWA breaks down.
Herbers, Claudia R; Johnston, Karen; van der Vegt, Nico F A
2011-06-14
We present an automated and efficient method to develop force fields for molecule-surface interactions. A genetic algorithm (GA) is used to parameterise a classical force field so that the classical adsorption energy landscape of a molecule on a surface matches the corresponding landscape from density functional theory (DFT) calculations. The procedure performs a sophisticated search in the parameter phase space and converges very quickly. The method is capable of fitting a significant number of structures and corresponding adsorption energies. Water on a ZnO(0001) surface was chosen as a benchmark system but the method is implemented in a flexible way and can be applied to any system of interest. In the present case, pairwise Lennard Jones (LJ) and Coulomb potentials are used to describe the molecule-surface interactions. In the course of the fitting procedure, the LJ parameters are refined in order to reproduce the adsorption energy landscape. The classical model is capable of describing a wide range of energies, which is essential for a realistic description of a fluid-solid interface.
A Plasma Proteomic Approach in Rett Syndrome: Classical versus Preserved Speech Variant
Cortelazzo, Alessio; Guerranti, Roberto; De Felice, Claudio; Leoncini, Silvia; Landi, Claudia; Montomoli, Barbara; Sticozzi, Claudia; Ciccoli, Lucia; Hayek, Joussef
2013-01-01
Rett syndrome (RTT) is a progressive neurodevelopmental disorder mainly caused by mutations in the gene encoding the methyl-CpG-binding protein 2 (MeCP2). Although over 200 mutations types have been identified so far, nine of which the most frequent ones. A wide phenotypical heterogeneity is a well-known feature of the disease, with different clinical presentations, including the classical form and the preserved speech variant (PSV). Aim of the study was to unveil possible relationships between plasma proteome and phenotypic expression in two cases of familial RTT represented by two pairs of sisters, harbor the same MECP2 gene mutation while being dramatically discrepant in phenotype, that is, classical RTT versus PSV. Plasma proteome was analysed by 2-DE/MALDI-TOF MS. A significant overexpression of six proteins in the classical sisters was detected as compared to the PSV siblings. A total of five out of six (i.e., 83.3%) of the overexpressed proteins were well-known acute phase response (APR) proteins, including alpha-1-microglobulin, haptoglobin, fibrinogen beta chain, alpha-1-antitrypsin, and complement C3. Therefore, the examined RTT siblings pairs proved to be an important benchmark model to test the molecular basis of phenotypical expression variability and to identify potential therapeutic targets of the disease. PMID:24453418
A plasma proteomic approach in Rett syndrome: classical versus preserved speech variant.
Cortelazzo, Alessio; Guerranti, Roberto; De Felice, Claudio; Signorini, Cinzia; Leoncini, Silvia; Pecorelli, Alessandra; Landi, Claudia; Bini, Luca; Montomoli, Barbara; Sticozzi, Claudia; Ciccoli, Lucia; Valacchi, Giuseppe; Hayek, Joussef
2013-01-01
Rett syndrome (RTT) is a progressive neurodevelopmental disorder mainly caused by mutations in the gene encoding the methyl-CpG-binding protein 2 (MeCP2). Although over 200 mutations types have been identified so far, nine of which the most frequent ones. A wide phenotypical heterogeneity is a well-known feature of the disease, with different clinical presentations, including the classical form and the preserved speech variant (PSV). Aim of the study was to unveil possible relationships between plasma proteome and phenotypic expression in two cases of familial RTT represented by two pairs of sisters, harbor the same MECP2 gene mutation while being dramatically discrepant in phenotype, that is, classical RTT versus PSV. Plasma proteome was analysed by 2-DE/MALDI-TOF MS. A significant overexpression of six proteins in the classical sisters was detected as compared to the PSV siblings. A total of five out of six (i.e., 83.3%) of the overexpressed proteins were well-known acute phase response (APR) proteins, including alpha-1-microglobulin, haptoglobin, fibrinogen beta chain, alpha-1-antitrypsin, and complement C3. Therefore, the examined RTT siblings pairs proved to be an important benchmark model to test the molecular basis of phenotypical expression variability and to identify potential therapeutic targets of the disease.
Shakib, Farnaz A; Hanna, Gabriel
2014-07-28
The nonadiabatic dynamics of model proton-coupled electron transfer (PCET) reactions is investigated for the first time using a surface-hopping algorithm based on the solution of the mixed quantum-classical Liouville equation (QCLE). This method provides a rigorous treatment of quantum coherence/decoherence effects in the dynamics of mixed quantum-classical systems, which is lacking in the molecular dynamics with quantum transitions surface-hopping approach commonly used for simulating PCET reactions. Within this approach, the protonic and electronic coordinates are treated quantum mechanically and the solvent coordinate evolves classically on both single adiabatic surfaces and on coherently coupled pairs of adiabatic surfaces. Both concerted and sequential PCET reactions are studied in detail under various subsystem-bath coupling conditions and insights into the dynamical principles underlying PCET reactions are gained. Notably, an examination of the trajectories reveals that the system spends the majority of its time on the average of two coherently coupled adiabatic surfaces, during which a phase enters into the calculation of an observable. In general, the results of this paper demonstrate the applicability of QCLE-based surface-hopping dynamics to the study of PCET and emphasize the importance of mean surface evolution and decoherence effects in the calculation of PCET rate constants.
A Stochastic Foundation of the Approach to Equilibrium of Classical and Quantum Gases
NASA Astrophysics Data System (ADS)
Costantini, D.; Garibaldi, U.
The Ehrenfest urn model is one of the most instructive models in the whole of Physics. It was thought to give a qualitative account for notions like reversibility, periodicity and tendency to equilibrium. The model, often referred to as the Ehrenfest dog-flea model, is mentioned in almost every textbook of probability, stochastic processes and statistical physics. Ehrenfest's model must not be limited to classical particles, but it can be extended to quantum particles. We make this extention in a purely probabilistic way. We do not refer to notions like (in)distinguishability that, in our opinion, have an epistemological and physical status far from clear. For all types of particles, we deduce the equilibrium probabilities in a purely probabilistic way. To accomplish our goal, we start by considering a set of probability conditions. On this basis, we deduce the formulae of creation and destruction probabilities for classical particles, bosons and fermions. These enable the deduction of the transition probabilities we are interested in. Via the master equation, these transition probabilities enable us to derive the equilibrium distributions.
NASA Astrophysics Data System (ADS)
Castellanos, L.; Calás, H.; Ramos, A.
2010-01-01
In this paper, an approach for simplifying the experimental arrangement, needed to generate limited diffracting waves through annular ultrasonic arrays, is analyzed in terms mainly of the subsequent acoustic field. The main idea is to approximate the theoretical X-wave electrical excitations to rectangular driving signals in each array annulus, by means of the L2 curve criterion. The differences between theoretical X-wave signals and these approximate signals, related to real excitation effects, were minimized by using the transition times and amplitudes of the rectangular signals as fitting parameters. Acoustic field simulations, based on the impulse response technique, are applied for evaluating the agreement degree between both emitted ultrasonic fields, whit the calculated classical X wave and with the new approximation method proposed here for low-cost limited-diffraction wave generation. In addition, source vibration and ultrasonic field simulated signals were compared with those of the classic x wave under an exact driving, with the purpose of validating the method. The good agreement between the two vibration signals and resulting field distributions, obtained from the classical X wave excitations and those provided by the drastic simplification presented here, can be justified by the filtering effects induced by the transducer elements bands in frequency domain. These results suggest the possibility of achieving limited diffraction waves with relatively simple driving waveforms, which can be implemented with a moderate cost in analogical electronics.
Chandrasekhar limit: an elementary approach based on classical physics and quantum theory
NASA Astrophysics Data System (ADS)
Pinochet, Jorge; Van Sint Jan, Michael
2016-05-01
In a brief article published in 1931, Subrahmanyan Chandrasekhar made public an important astronomical discovery. In his article, the then young Indian astrophysicist introduced what is now known as the Chandrasekhar limit. This limit establishes the maximum mass of a stellar remnant beyond which the repulsion force between electrons due to the exclusion principle can no longer stop the gravitational collapse. In the present article, we create an elemental approximation to the Chandrasekhar limit, accessible to non-graduate science and engineering students. The article focuses especially on clarifying the origins of Chandrasekhar’s discovery and the underlying physical concepts. Throughout the article, only basic algebra is used as well as some general notions of classical physics and quantum theory.
A Unified Approach to Conformational Statistics of Classical Polymer and Polypeptide Models
Kim, Jin Seob; Chirikjian, Gregory S.
2010-01-01
We present a unified method to generate conformational statistics which can be applied to any of the classical discrete-chain polymer models. The proposed method employs the concepts of Fourier transform and generalized convolution for the group of rigid-body motions in order to obtain probability density functions of chain end-to-end distance. In this paper, we demonstrate the proposed method with three different cases: the freely-rotating model, independent energy model, and interdependent pairwise energy model (the last two are also well-known as the Rotational Isomeric State model). As for numerical examples, for simplicity, we assume homogeneous polymer chains. For the freely-rotating model, we verify the proposed method by comparing with well-known closed-form results for mean-squared end-to-end distance. In the interdependent pairwise energy case, we take polypeptide chains such as polyalanine and polyvaline as examples. PMID:20165562
Sequencing approach to analyze the role of quasispecies for classical swine fever.
Töpfer, Armin; Höper, Dirk; Blome, Sandra; Beer, Martin; Beerenwinkel, Niko; Ruggli, Nicolas; Leifer, Immanuel
2013-03-30
Classical swine fever virus (CSFV) is a positive-sense RNA virus with a high degree of genetic variability among isolates. High diversity is also found in virulence, with strains covering the complete spectrum from avirulent to highly virulent. The underlying genetic determinants are far from being understood. Since RNA polymerases of RNA viruses lack any proof-reading activity, different genome variations called haplotypes, occur during replication. A set of haplotypes is referred to as a viral quasispecies. Genetic variability can be a fitness advantage through facilitating of a more effective escape from the host immune response. In order to investigate the correlation of quasispecies composition and virulence in vivo, we analyzed next-generation sequencing data of CSFV isolates of varying virulence. Viral samples from pigs infected with the highly virulent isolates "Koslov" and "Brescia" showed higher quasispecies diversity and more nucleotide variability, compared to samples of pigs infected with low and moderately virulent isolates.
A new approach to the classical and quantum dynamics of branes
NASA Astrophysics Data System (ADS)
Pavšič, Matej
2016-07-01
It is shown that the Dirac-Nambu-Goto brane can be described as a point particle in an infinite-dimensional brane space with a particular metric. This suggests a generalization to brane spaces with arbitrary metric, including the “flat” metric. Then quantization of such a system is straightforward: it is just like quantization of a bunch of noninteracting particles. This leads us to a system of a continuous set of scalar fields. For a particular choice of the metric in the space of fields we find that the classical Dirac-Nambu-Goto brane theory arises as an effective theory of such an underlying quantum field theory. Quantization of branes is important for the brane world scenarios, and thus for “quantum gravity.”
Benassi, Filippo; Manca, Tullio; Ramelli, Andrea; Vezzani, Antonella; Nicolini, Francesco; Romano, Giorgio; Ricci, Matteo; Carino, Davide; Di Chicco, Maria Vincenza; Gherli, Tiziano
2016-01-01
Background The aim of our study is to compare the classical surgical tracheostomy (TT) technique with a modified surgical technique designed and created by the cardiothoracic surgery staff of our department to reduce surgical trauma and postoperative complications. This modified technique combines features of percutaneous TT and surgical TT avoiding the use of specialized tools, which are required in percutaneous TT. Methods From October 2008 to March 2014 we performed 67 tracheostomies using this New Modified Surgical Technique (NMST) and 56 TT with the Classical Surgical Technique (CST). We collected data about the early clinical complications, deaths TT-related, deaths due to other complications and the presence of late TT’s complications were performed by a telephone follow-up. SPSS software (IMB version 21) was used for the statistical analysis. Categorical data were treated with chi-square test and continuous data were treated with t-test for independent samples. Results NMST group had a significant lower number of early complications (P=0.005) compared to CST group (5 vs. 15). In-hospital mortality was significantly higher in CST group (18 deaths vs. 4 in NMST group, P=0.001) but we registered only one case of TT-related mortality in CST group (P=0.280). We did not note other differences between the two groups regarding short or mid-long term complications. Conclusions In our experience the NMST demonstrated to be easily safe and reproducible with an amount of early, mid- and long-term complications similar to the CST; furthermore the aesthetic results of the procedure appear similar to those of percutaneous TT. PMID:28149558
Niquet, Yann-Michel Nguyen, Viet-Hung; Duchemin, Ivan; Nier, Olivier; Rideau, Denis
2014-02-07
We discuss carrier mobilities in the quantum Non-Equilibrium Green's Functions (NEGF) framework. We introduce a method for the extraction of the mobility that is free from contact resistance contamination and with minimal needs for ensemble averages. We focus on silicon thin films as an illustration, although the method can be applied to various materials such as semiconductor nanowires or carbon nanostructures. We then introduce a new paradigm for the definition of the partial mobility μ{sub M} associated with a given elastic scattering mechanism “M,” taking phonons (PH) as a reference (μ{sub M}{sup −1}=μ{sub PH+M}{sup −1}−μ{sub PH}{sup −1}). We argue that this definition makes better sense in a quantum transport framework as it is free from long range interference effects that can appear in purely ballistic calculations. As a matter of fact, these mobilities satisfy Matthiessen's rule for three mechanisms [e.g., surface roughness (SR), remote Coulomb scattering (RCS) and phonons] much better than the usual, single mechanism calculations. We also discuss the problems raised by the long range spatial correlations in the RCS disorder. Finally, we compare semi-classical Kubo-Greenwood (KG) and quantum NEGF calculations. We show that KG and NEGF are in reasonable agreement for phonon and RCS, yet not for SR. We discuss the reasons for these discrepancies.
NASA Astrophysics Data System (ADS)
Niquet, Yann-Michel; Nguyen, Viet-Hung; Triozon, François; Duchemin, Ivan; Nier, Olivier; Rideau, Denis
2014-02-01
We discuss carrier mobilities in the quantum Non-Equilibrium Green's Functions (NEGF) framework. We introduce a method for the extraction of the mobility that is free from contact resistance contamination and with minimal needs for ensemble averages. We focus on silicon thin films as an illustration, although the method can be applied to various materials such as semiconductor nanowires or carbon nanostructures. We then introduce a new paradigm for the definition of the partial mobility μM associated with a given elastic scattering mechanism "M," taking phonons (PH) as a reference (μM-1=μPH+M-1-μPH-1). We argue that this definition makes better sense in a quantum transport framework as it is free from long range interference effects that can appear in purely ballistic calculations. As a matter of fact, these mobilities satisfy Matthiessen's rule for three mechanisms [e.g., surface roughness (SR), remote Coulomb scattering (RCS) and phonons] much better than the usual, single mechanism calculations. We also discuss the problems raised by the long range spatial correlations in the RCS disorder. Finally, we compare semi-classical Kubo-Greenwood (KG) and quantum NEGF calculations. We show that KG and NEGF are in reasonable agreement for phonon and RCS, yet not for SR. We discuss the reasons for these discrepancies.
Eyeblink classical conditioning and post-traumatic stress disorder - a model systems approach.
Schreurs, Bernard G; Burhans, Lauren B
2015-01-01
Not everyone exposed to trauma suffers flashbacks, bad dreams, numbing, fear, anxiety, sleeplessness, hyper-vigilance, hyperarousal, or an inability to cope, but those who do may suffer from post-traumatic stress disorder (PTSD). PTSD is a major physical and mental health problem for military personnel and civilians exposed to trauma. There is still debate about the incidence and prevalence of PTSD especially among the military, but for those who are diagnosed, behavioral therapy and drug treatment strategies have proven to be less than effective. A number of these treatment strategies are based on rodent fear conditioning research and are capable of treating only some of the symptoms because the extinction of fear does not deal with the various forms of hyper-vigilance and hyperarousal experienced by people with PTSD. To help address this problem, we have developed a preclinical eyeblink classical conditioning model of PTSD in which conditioning and hyperarousal can both be extinguished. We review this model and discuss findings showing that unpaired stimulus presentations can be effective in reducing levels of conditioning and hyperarousal even when unconditioned stimulus intensity is reduced to the point where it is barely capable of eliciting a response. These procedures have direct implications for the treatment of PTSD and could be implemented in a virtual reality environment.
Evans, Deborah J; Owlarn, Suthira; Tejada Romero, Belen; Chen, Chen; Aboobaker, A Aziz
2011-01-01
The current model of planarian anterior regeneration evokes the establishment of low levels of Wnt signalling at anterior wounds, promoting anterior polarity and subsequent elaboration of anterior fate through the action of the TALE class homeodomain PREP. The classical observation that decapitations positioned anteriorly will regenerate heads more rapidly than posteriorly positioned decapitations was among the first to lead to the proposal of gradients along an anteroposterior (AP) axis in a developmental context. An explicit understanding of this phenomenon is not included in the current model of anterior regeneration. This raises the question what the underlying molecular and cellular basis of this temporal gradient is, whether it can be explained by current models and whether understanding the gradient will shed light on regenerative events. Differences in anterior regeneration rate are established very early after amputation and this gradient is dependent on the activity of Hedgehog (Hh) signalling. Animals induced to produce two tails by either Smed-APC-1(RNAi) or Smed-ptc(RNAi) lose anterior fate but form previously described ectopic anterior brain structures. Later these animals form peri-pharyngeal brain structures, which in Smed-ptc(RNAi) grow out of the body establishing a new A/P axis. Combining double amputation and hydroxyurea treatment with RNAi experiments indicates that early ectopic brain structures are formed by uncommitted stem cells that have progressed through S-phase of the cell cycle at the time of amputation. Our results elaborate on the current simplistic model of both AP axis and brain regeneration. We find evidence of a gradient of hedgehog signalling that promotes posterior fate and temporarily inhibits anterior regeneration. Our data supports a model for anterior brain regeneration with distinct early and later phases of regeneration. Together these insights start to delineate the interplay between discrete existing, new, and then
Thermodynamic Perturbation Approach to Freezing of the Classical One-Component Plasma
NASA Astrophysics Data System (ADS)
Hasegawa, Masayuki
1995-11-01
Systematic investigations are made of the thermodynamic perturbationapproach to freezing, which has proved successful for systemsinteracting through soft-core or long-ranged potentials. The classicalone-component plasma (OCP) is taken as the extreme case of suchsystems and the investigations focus on the reference systems employedin this approach and on the approximation schemes used to treat thatsystem. It is confirmed that good results are obtained for thefreezing properties of the OCP if a system with repulsive,short-ranged potential is properly chosen as the reference system, andboth this system and the remaining part due to the long-rangeinteraction are separately treated by the modified weighted-densityapproximation (MWDA) using accurate input data. However, if we adoptthe hard spheres as the reference system in this approach and useeither the MWDA or the generalized effective-liquid approximation(GELA) for this system, we cannot get similar results unless we usethe input data in the Percus-Yevick (PY) approximation rather than thevirtually \\lq\\lqexact” ones. This unfavorable result throwsserious doubt on the usefulness of the hard spheres as the referencesystem.
Report on noninvasive prenatal testing: classical and alternative approaches.
Pantiukh, Kateryna S; Chekanov, Nikolay N; Zaigrin, Igor V; Zotov, Alexei M; Mazur, Alexander M; Prokhortchouk, Egor B
2016-01-01
Concerns of traditional prenatal aneuploidy testing methods, such as low accuracy of noninvasive and health risks associated with invasive procedures, were overcome with the introduction of novel noninvasive methods based on genetics (NIPT). These were rapidly adopted into clinical practice in many countries after a series of successful trials of various independent submethods. Here we present results of own NIPT trial carried out in Moscow, Russia. 1012 samples were subjected to the method aimed at measuring chromosome coverage by massive parallel sequencing. Two alternative approaches are ascertained: one based on maternal/fetal differential methylation and another based on allelic difference. While the former failed to provide stable results, the latter was found to be promising and worthy of conducting a large-scale trial. One critical point in any NIPT approach is the determination of fetal cell-free DNA fraction, which dictates the reliability of obtained results for a given sample. We show that two different chromosome Y representation measures-by real-time PCR and by whole-genome massive parallel sequencing-are practically interchangeable (r=0.94). We also propose a novel method based on maternal/fetal allelic difference which is applicable in pregnancies with fetuses of either sex. Even in its pilot form it correlates well with chromosome Y coverage estimates (r=0.74) and can be further improved by increasing the number of polymorphisms.
Bisi, A; Gobbi, S; Belluti, F; Rampa, A
2013-01-01
Cardiovascular disease represents the main cause of death worldwide. Novel therapies to reduce elevated blood pressure and treat resistant hypertension, to consequently reduce the associated cardiovascular risk factors, are still required. Among the different strategies commonly used in medicinal chemistry to develop new molecules, the synthesis of multitarget/hybrid compounds combining two or more pharmacophore groups targeting simultaneously selected factors involved in cardiovascular diseases, has gained increasing interest. This review will focus on the most recent literature on multifunctional cardiovascular drugs, paying particular attention on hybrid compounds bearing natural scaffolds, considering that compounds derived from medicinal extracts are generally appealing for the medicinal chemist as they often bear the so-called "privileged structures". Moreover, taking into account many excellent reviews dealing with multitarget cardiovascular drugs published in the last few years, mainly devoted to RAAS inhibition and/or NO donors hybrid drugs, herein the most significant results obtained and the benefits and limitations of these approaches will be highlighted.
NASA Astrophysics Data System (ADS)
Wishart, D. N.
2014-12-01
An integrated approach incorporating multicomponent and classical solute geothermometry was used to evaluate its utility to estimate the temperature of the Bath geothermal reservoir, a low-enthalpy system on the island of Jamaica. Reservoir temperatures were estimated from (1) empirical geothermometric equations; (2) simulations of solute geothermometers using SolGeo software; (3) computations of saturation indices [Log(Q/K)] of reservoir minerals from full chemically-analyzed thermal water samples over a temperature range of 25-220°C in PHREEQC; and (4) the Giggenbach Na-K-Mg geothermometer. A principal component analysis (PCA) shows strong, positive correlations between Na+, K+, and Mg2+ and is regarded as significant for these ions in their reliance as useful reservoir geoindicators. However, a negative correlation exists between Na+, K+, Mg2+ and silica (SiO2). The more realistic estimates of the geothermal reservoir temperature were provided by the Na-K and Na-K-Mg geothermometers, whereas the Na-K-Ca geothermometer overestimated reservoir temperatures. Estimated geotemperatures from silica-quartz geothermometers were the lowest. The discrepancy in estimated geotemperatures may be due to processes such as boiling, degassing, dilution, rock dissolution, and mixing during the ascent of geothermal fluids. Log (Q/K) curves cluster over a range of equilibrium temperatures closest to Na-K and Na-K-Mg geothermometers at 80-102°C. Reservoir temperatures estimated for the Bath geothermal system range between 79-118°C. Comparisons of the estimated geotemperatures using the integrated approach to geothermometry show a favorable agreement. Based on the results of this investigation, the integrated geothermometric approach provided a more reliable approach to reconstruct the fluid composition at depth and estimate the geothermal reservoir temperature.
NASA Astrophysics Data System (ADS)
Trahan, Corey J.; Wyatt, Robert E.
2003-10-01
Recently, Donoso and Martens described a method for evolving both classical and quantum phase-space distribution functions, W(q,p,t), that involves the propagation of an ensemble of correlated trajectories. The trajectories are linked into a unified whole by spatial and momentum derivatives of density dependent terms in the equations of motion. On each time step, these nonlocal terms were evaluated by fitting the density around each trajectory to an assumed functional form. In the present study, we develop a different trajectory method for propagating phase-space distribution functions. A hierarchy of coupled analytic equations of motion are derived for the q and p derivatives of the density and a truncated set of these are integrated along each trajectory concurrently with the equation of motion for the density. The advantage of this approach is that individual trajectories can be propagated, one at a time, and function fitting is not required to evaluate the nonlocal terms. Regional nonlocality can be incorporated at various levels of approximation to "dress" what would otherwise be "thin" locally propagating trajectories. This derivative propagation method is used to obtain trajectory solutions for the Klein-Kramers equation, the Husimi equation, and for a smoothed version of the Caldeira-Leggett equation derived by the Diosi. Trajectory solutions are obtained for the relaxation of an oscillator in contact with a thermal bath and for the decay of a metastable state.
NASA Astrophysics Data System (ADS)
Makino, Hironori; Minami, Nariyuki
2014-07-01
The theory of the quantal level statistics of a classically integrable system, developed by Makino et al. in order to investigate the non-Poissonian behaviors of level-spacing distribution (LSD) and level-number variance (LNV) [H. Makino and S. Tasaki, Phys. Rev. E 67, 066205 (2003); H. Makino and S. Tasaki, Prog. Theor. Phys. Suppl. 150, 376 (2003); H. Makino, N. Minami, and S. Tasaki, Phys. Rev. E 79, 036201 (2009); H. Makino and S. Tasaki, Prog. Theor. Phys. 114, 929 (2005)], is successfully extended to the study of the E(K,L) function, which constitutes a fundamental measure to determine most statistical observables of quantal levels in addition to LSD and LNV. In the theory of Makino et al., the eigenenergy level is regarded as a superposition of infinitely many components whose formation is supported by the Berry-Robnik approach in the far semiclassical limit [M. Robnik, Nonlinear Phenom. Complex Syst. 1, 1 (1998)]. We derive the limiting E(K,L) function in the limit of infinitely many components and elucidate its properties when energy levels show deviations from the Poisson statistics.
NASA Astrophysics Data System (ADS)
Rey, Angel M.; Román-Roy, Narciso; Salgado, Modesto
2005-05-01
The first aim of this paper is to extend the Skinner-Rusk formalism on classical mechanics for first-order field theories. The second is to generalize the definition and properties of the evolution K-operator on classical mechanics for first-order field theories using in both cases Günther's formalism (k-symplectic formalism).
Chen, Hanning; McMahon, J. M.; Ratner, Mark A.; Schatz, George C.
2010-09-02
A new multiscale computational methodology was developed to effectively incorporate the scattered electric field of a plasmonic nanoparticle into a quantum mechanical (QM) optical property calculation for a nearby dye molecule. For a given location of the dye molecule with respect to the nanoparticle, a frequency-dependent scattering response function was first determined by the classical electrodynamics (ED) finite-difference time-domain (FDTD) approach. Subsequently, the time-dependent scattered electric field at the dye molecule was calculated using the FDTD scattering response function through a multidimensional Fourier transform to reflect the effect of polarization of the nanoparticle on the local field at the molecule. Finally, a real-time time-dependent density function theory (RT-TDDFT) approach was employed to obtain a desired optical property (such as absorption cross section) of the dye molecule in the presence of the nanoparticle’s scattered electric field. Our hybrid QM/ED methodology was demonstrated by investigating the absorption spectrum of the N3 dye molecule and the Raman spectrum of pyridine, both of which were shown to be significantly enhanced by a 20 nm diameter silver sphere. In contrast to traditional quantum mechanical optical calculations in which the field at the molecule is entirely determined by intensity and polarization direction of the incident light, in this work we show that the light propagation direction as well as polarization and intensity are important to nanoparticle-bound dye molecule response. At no additional computation cost compared to conventional ED and QM calculations, this method provides a reliable way to couple the response of the dye molecule’s individual electrons to the collective dielectric response of the nanoparticle.
Dou, Wenjie; Subotnik, Joseph E
2016-01-14
A broadened classical master equation (BCME) is proposed for modeling nonadiabatic dynamics for molecules near metal surfaces over a wide range of parameter values and with arbitrary initial conditions. Compared with a standard classical master equation-which is valid in the limit of weak molecule-metal couplings-this BCME should be valid for both weak and strong molecule-metal couplings. (The BCME can be mapped to a Fokker-Planck equation that captures level broadening correctly.) Finally, our BCME can be solved with a simple surface hopping algorithm; numerical tests of equilibrium and dynamical observables look very promising.
ERIC Educational Resources Information Center
Clayman, Dee L.
1995-01-01
Appraises several databases devoted to classical literature. Thesaurus Linguae Graecae (TLG) contains the entire extant corpus of ancient Greek literature, including works on lexicography and historiography, extending into the 15th century. Other works awaiting completion are the Database of Classical Bibliography and a CD-ROM pictorial dictionary…
NASA Astrophysics Data System (ADS)
Torrielli, Alessandro
2016-08-01
We review some essential aspects of classically integrable systems. The detailed outline of the sections consists of: 1. Introduction and motivation, with historical remarks; 2. Liouville theorem and action-angle variables, with examples (harmonic oscillator, Kepler problem); 3. Algebraic tools: Lax pairs, monodromy and transfer matrices, classical r-matrices and exchange relations, non-ultralocal Poisson brackets, with examples (non-linear Schrödinger model, principal chiral field); 4. Features of classical r-matrices: Belavin-Drinfeld theorems, analyticity properties, and lift of the classical structures to quantum groups; 5. Classical inverse scattering method to solve integrable differential equations: soliton solutions, spectral properties and the Gel’fand-Levitan-Marchenko equation, with examples (KdV equation, Sine-Gordon model). Prepared for the Durham Young Researchers Integrability School, organised by the GATIS network. This is part of a collection of lecture notes.
Mavri, Janez; Liu, Hanbin; Olsson, Mats H M; Warshel, Arieh
2008-05-15
The ability of using wave function propagation approaches to simulate isotope effects in enzymes is explored, focusing on the large H/D kinetic isotope effect of soybean lipoxygenase-1 (SLO-1). The H/D kinetic isotope effect (KIE) is calculated as the ratio of the rate constants for hydrogen and deuterium transfer. The rate constants are calculated from the time course of the H and D nuclear wave functions. The propagations are done using one-dimensional proton potentials generated as sections from the full multidimensional surface of the reacting system in the protein. The sections are obtained during a classical empirical valence bond (EVB) molecular dynamics simulation of SLO-1. Since the propagations require an extremely long time for treating realistic activation barriers, it is essential to use an effective biasing approach. Thus, we develop here an approach that uses the classical quantum path (QCP) method to evaluate the quantum free energy change associated with the biasing potential. This approach provides an interesting alternative to full QCP simulations and to other current approaches for simulating isotope effects in proteins. In particular, this approach can be used to evaluate the quantum mechanical transmission factor or other dynamical effects, while still obtaining reliable quantized activation free energies due to the QCP correction.
NASA Astrophysics Data System (ADS)
Tran, H. N.; Dao, D. D.; Incerti, S.; Bernal, M. A.; Karamitros, M.; Nhan Hao, T. V.; Dang, T. M.; Francis, Z.
2016-01-01
In this work, we present a derivation of cross sections for single ionization and electron capture processes within the Classical Trajectory Monte Carlo (CTMC) approach. Specifically, we have used a potential stemming from an ab initio calculation in Green et al.'s framework to describe the dynamics of the water molecule system. Proposing a modified version of the Classical Over-Barrier (COB) potential, we have found that a cut-off of roughly 28 a.u. on the initial distance of the projectile produced a reasonable accuracy. A global agreement has been obtained in our calculations compared to experimental and other theoretical results for C6+ ion energies ranging from 10 keV/u to 10 MeV/u.
Classical and quantum field-theoretical approach to the non-linear q-Klein-Gordon equation
NASA Astrophysics Data System (ADS)
Plastino, A.; Rocca, M. C.
2016-11-01
In the wake of efforts made Nobre and Rego-Monteiro in EPL, 97 (2012) 41001 and J. Math. Phys., 54 (2913) 103302, we extend them here by developing the conventional Lagrangian treatment of a classical field theory (FT) to the q-Klein-Gordon equation advanced in Phys. Rev. Lett., 106 (2011) 140601 and J. Math. Phys., 54 (2913) 103302 by the same authors, and the quantum theory corresponding to q=\\frac {3} {2} . This makes it possible to generate a putative conjecture regarding black matter. Our theory reduces to the usual FT for q→ 1 .
NASA Astrophysics Data System (ADS)
Zhidkov, A.; Masuda, S.; Bulanov, S. S.; Koga, J.; Hosokai, T.; Kodama, R.
2014-05-01
Nonlinear cascade scattering of intense, tightly focused laser pulses by relativistic electrons is studied numerically in the classical approximation including radiation damping for the quantum parameter ⟨ℏωxray⟩/ɛ <1 and an arbitrary radiation parameter χ. The electron's energy loss, along with its being scattered to the side by the ponderomotive force, makes scattering in the vicinity of a high laser field nearly impossible at high electron energies. The use of a second, copropagating laser pulse as a booster is shown to partially solve this problem.
NASA Astrophysics Data System (ADS)
Arvind; Chaturvedi, S.; Mukunda, N.
2017-04-01
We examine a recent proposal to show the presence of nonlocal Pancharatnam type geometric phases in a quantum mechanical treatment of intensity interferometry measurements upon inclusion of polarizing elements in the setup. It is shown that a completely classical statistical treatment of such effects is adequate for practical purposes. Further we show that the phase angles that appear in the correlations, while at first sight appearing to resemble Pancharatnam phases in their mathematical structure, cannot actually be interpreted in that manner. We also describe a simpler Mach-Zehnder type setup where similar effects can be observed without use of the paraxial approximation.
NASA Astrophysics Data System (ADS)
Bode, Michael F.; Evans, Aneurin
2012-07-01
Preface; 1. Novae - a historical perspective Hilmar W. Duerbeck; 2. Properties of novae: an overview Brian Warner; 3. The evolution of nova-producing binary stars Icko Iben, Jr and Masayuki Y. Fujimoto; 4. Thermonuclear processes S. Starrfield, C. Iliadis and W. R. Hix; 5. Nova atmospheres and winds P. H. Hauschildt; 6. Observational mysteries and theoretical challenges Jordi Jose and Steven N. Shore; 7. Radio emission from novae E. R. Seaquist and M. F. Bode; 8. Infrared studies of classical novae Robert D. Gehrz; 9. Optical and ultraviolet evolution Steven N. Shore; 10. X-ray emission from classical novae in outburst Joachim Krautter; 11. Gamma-rays from classical novae Margarita Hernanz; 12. Resolved nova remnants T. J. O'Brien and M. F. Bode; 13. Dust and molecules in nova environments A. Evans and J. M. C. Rawlings; 14. Extragalactic novae Allen Shafter; Index.
Kastner, Michael
2011-03-01
The stationary points of the potential energy function V of the classical XY chain with power-law pair interactions (i.e., interactions decaying like r{-α} with the distance) are analyzed. For a class of "spinwave-type" stationary points, the asymptotic behavior of the Hessian determinant of V is computed analytically in the limit of large system size. The computation is based on the Toeplitz property of the Hessian and makes use of a Szegö-type theorem. The results serve to illustrate a recently discovered relation between phase transitions and the properties of stationary points of classical many-body potentials. In agreement with this relation, the exact phase transition potential energy of the model can be read off from the behavior of the Hessian determinant for exponents α between zero and one. For α between one and two, the phase transition is not manifest in the behavior of the determinant, and it might be necessary to consider larger classes of stationary points.
NASA Astrophysics Data System (ADS)
Oliynyk, Todd A.
2016-12-01
We introduce a new approach to analyzing the interaction between classical and quantum systems that is based on a limiting procedure applied to multi-particle Schrödinger equations. The limit equations obtained by this procedure, which we refer to as the classical-quantum limit, govern the interaction between classical and quantum systems, and they possess many desirable properties that are inherited in the limit from the multi-particle quantum system. As an application, we use the classical-quantum limit equations to identify the source of the non-local signalling that is known to occur in the classical-quantum hybrid scheme of Hall and Reginatto. We also derive the first order correction to the classical-quantum limit equation to obtain a fully consistent first order approximation to the Schrödinger equation that should be accurate for modeling the interaction between particles of disparate mass in the regime where the particles with the larger masses are effectively classical.
NASA Astrophysics Data System (ADS)
Chow, Tai L.
1995-05-01
Bring Classical Mechanics To Life With a Realistic Software Simulation! You can enhance the thorough coverage of Chow's Classical Mechanics with a hands-on, real-world experience! John Wiley & Sons, Inc. is proud to announce a new computer simulation for classical mechanics. Developed by the Consortium for Upper-Level Physics Software (CUPS), this simulation offers complex, often realistic calculations of models of various physical systems. Classical Mechanics Simulations (54881-2) is the perfect complement to Chow's text. Like all of the CUPS simulations, it is remarkably easy to use, yet sophisticated enough for explorations of new ideas. Other Important Features Include: * Six powerful simulations include: The Motion Generator, Rotation of Three-Dimensional Objects, Coupled Oscillators, Anharmonic Oscillators, Gravitational Orbits, and Collisions * Pascal source code for all programs is supplied and a number of exercises suggest specific ways the programs can be modified. * Simulations usually include graphical (often animated) displays. The entire CUPS simulation series consists of nine book/software simulations which comprise most of the undergraduate physics major's curriculum.
Hincak, Zdravka; Drmić-Hofman, Irena; Mihelić, Damir
2007-12-01
Theories about the first Indo-European migration are numerous. Significant contribution in attempt to resolve these theories is given by analysing skeletal material from two biggest prehistoric archaeological sites from N-E Croatia. Eight skeletons of Starcevo culture from sites "Nama" and "Hotel" at Vinkovci (6100-5500 BC) and seven skeletons of Vucedol culture from the site Vineyard Streim at Vucedol near Vukovar (3000-2500 BC) were analysed. Methods of classical anthropological analysis tried to distinguish the differences among members of both populations, while the methods of molecular genetics were used in defining possible genetic structure of both ancient populations. Established differences speak on the behalf of the theory of Maria Gimbutas about the first Indo-European migration with a cattle breeding population from the east around 3500 BC.
Viridi, S.; Kurniadi, R.; Waris, A.; Perkasa, Y. S.
2012-06-06
Molecular dynamics in 2-D accompanied by granular model provides an opportunity to investigate binding between nuclei particles and its properties that arises during collision in a fusion reaction. A fully classical approach is used to observe the influence of initial angle of nucleus orientation to the product yielded by the reaction. As an example, a simplest fusion reaction between {sub 1}H{sup 2} and {sub 1}H{sup 3} is observed. Several products of the fusion reaction have been obtained, even the unreported ones, including temporary {sub 2}He{sup 4} nucleus.
Sevryuk, Mikhail B.; Lombardi, Andrea; Aquilanti, Vincenzo
2005-09-15
Rigorous and complete definitions of two partitions and one expansion for the kinetic energy of a general N-particle classical system are given. Our recent work, which also provides examples of applications to the molecular dynamics of nanoaggregates, based on computer programs formulated on the basis of the theory presented here, is extended to cover arbitrary physical space dimensions. The partitions and the expansion are in terms of quantities conceived to be instantaneous phase-space invariants - a far-reaching generalization of integrals of the motion. These quantities are introduced setting out as starting points the position matrix Z of the system and the time derivative of Z. In the simplest case, the matrix Z contains the mass-scaled Cartesian coordinates of the N particles. From the position matrix, the kinematic rotations naturally arise through orthogonal transformations, as a concept 'dual' to the ordinary physical rotations. The physical meaning of each partition (expansion) term is clearly described and emphasized, and formulas for the various quantities are provided as well as inequalities among them. Proofs are presented making extensive use of the singular value decomposition (SVD) of matrices and of the signed SVD, an extended version overcoming possible singularities for particular values of N.
Li, Xin; Carravetta, Vincenzo; Li, Cui; Monti, Susanna; Rinkevicius, Zilvinas; Ågren, Hans
2016-07-12
Motivated by the growing importance of organometallic nanostructured materials and nanoparticles as microscopic devices for diagnostic and sensing applications, and by the recent considerable development in the simulation of such materials, we here choose a prototype system - para-nitroaniline (pNA) on gold nanoparticles - to demonstrate effective strategies for designing metal nanoparticles with organic conjugates from fundamental principles. We investigated the motion, adsorption mode, and physical chemistry properties of gold-pNA particles, increasing in size, through classical molecular dynamics (MD) simulations in connection with quantum chemistry (QC) calculations. We apply the quantum mechanics-capacitance molecular mechanics method [Z. Rinkevicius et al. J. Chem. Theory Comput. 2014, 10, 989] for calculations of the properties of the conjugate nanoparticles, where time dependent density functional theory is used for the QM part and a capacitance-polarizability parametrization of the MM part, where induced dipoles and charges by metallic charge transfer are considered. Dispersion and short-range repulsion forces are included as well. The scheme is applied to one- and two-photon absorption of gold-pNA clusters increasing in size toward the nanometer scale. Charge imaging of the surface introduces red-shifts both because of altered excitation energy dependence and variation of the relative intensity of the inherent states making up for the total band profile. For the smaller nanoparticles the difference in the crystal facets are important for the spectral outcome which is also influenced by the surrounding MM environment.
Getting into Classical Chinese
ERIC Educational Resources Information Center
Kent, George W.
1976-01-01
The world of classical Chinese is distant both in time and space from the world of the English-speaking American. The instructor must not, however, use a no-attention-to-meaning approach assuming some words are untranslateable or create confusion in discussing the nature of Chinese script. (CFM)
Saccà, Maria Ludovica; Fajardo, Carmen; Costa, Gonzalo; Lobo, Carmen; Nande, Mar; Martin, Margarita
2014-06-01
Nanosized zero-valent iron (nZVI) is a new option for the remediation of contaminated soil and groundwater, but the effect of nZVI on soil biota is mostly unknown. In this work, nanotoxicological studies were performed in vitro and in two different standard soils to assess the effect of nZVI on autochthonous soil organisms by integrating classical and molecular analysis. Standardised ecotoxicity testing methods using Caenorhabditis elegans were applied in vitro and in soil experiments and changes in microbial biodiversity and biomarker gene expression were used to assess the responses of the microbial community to nZVI. The classical tests conducted in soil ruled out a toxic impact of nZVI on the soil nematode C. elegans in the test soils. The molecular analysis applied to soil microorganisms, however, revealed significant changes in the expression of the proposed biomarkers of exposure. These changes were related not only to the nZVI treatment but also to the soil characteristics, highlighting the importance of considering the soil matrix on a case by case basis. Furthermore, due to the temporal shift between transcriptional responses and the development of the corresponding phenotype, the molecular approach could anticipate adverse effects on environmental biota.
Randomness: Quantum versus classical
NASA Astrophysics Data System (ADS)
Khrennikov, Andrei
2016-05-01
Recent tremendous development of quantum information theory has led to a number of quantum technological projects, e.g. quantum random generators. This development had stimulated a new wave of interest in quantum foundations. One of the most intriguing problems of quantum foundations is the elaboration of a consistent and commonly accepted interpretation of a quantum state. Closely related problem is the clarification of the notion of quantum randomness and its interrelation with classical randomness. In this short review, we shall discuss basics of classical theory of randomness (which by itself is very complex and characterized by diversity of approaches) and compare it with irreducible quantum randomness. We also discuss briefly “digital philosophy”, its role in physics (classical and quantum) and its coupling to the information interpretation of quantum mechanics (QM).
NASA Astrophysics Data System (ADS)
Jagiello, Karolina; Grzonkowska, Monika; Swirog, Marta; Ahmed, Lucky; Rasulev, Bakhtiyor; Avramopoulos, Aggelos; Papadopoulos, Manthos G.; Leszczynski, Jerzy; Puzyn, Tomasz
2016-09-01
In this contribution, the advantages and limitations of two computational techniques that can be used for the investigation of nanoparticles activity and toxicity: classic nano-QSAR (Quantitative Structure-Activity Relationships employed for nanomaterials) and 3D nano-QSAR (three-dimensional Quantitative Structure-Activity Relationships, such us Comparative Molecular Field Analysis, CoMFA/Comparative Molecular Similarity Indices Analysis, CoMSIA analysis employed for nanomaterials) have been briefly summarized. Both approaches were compared according to the selected criteria, including: efficiency, type of experimental data, class of nanomaterials, time required for calculations and computational cost, difficulties in the interpretation. Taking into account the advantages and limitations of each method, we provide the recommendations for nano-QSAR modellers and QSAR model users to be able to determine a proper and efficient methodology to investigate biological activity of nanoparticles in order to describe the underlying interactions in the most reliable and useful manner.
Delgado, João; Pollard, Simon; Snary, Emma; Black, Edgar; Prpich, George; Longhurst, Phil
2013-08-01
Exotic animal diseases (EADs) are characterized by their capacity to spread global distances, causing impacts on animal health and welfare with significant economic consequences. We offer a critique of current import risk analysis approaches employed in the EAD field, focusing on their capacity to assess complex systems at a policy level. To address the shortcomings identified, we propose a novel method providing a systematic analysis of the likelihood of a disease incursion, developed by reference to the multibarrier system employed for the United Kingdom. We apply the network model to a policy-level risk assessment of classical swine fever (CSF), a notifiable animal disease caused by the CSF virus. In doing so, we document and discuss a sequence of analyses that describe system vulnerabilities and reveal the critical control points (CCPs) for intervention, reducing the likelihood of U.K. pig herds being exposed to the CSF virus.
Capuani, Caroline; Rouquette, Jacques; Payré, Bruno; Moscovici, Jacques; Delisle, Marie Bernadette; Telmon, Norbert; Guilbeau-Frugier, Céline
2013-01-01
Characterization of sharp-force trauma on human bones can be extremely useful in providing information regarding the nature and context of death. Nevertheless, in the identification of weapons used to cause sharp-force trauma and analysis of bone wounds, challenging tasks still remain. Current analysis attempting to dissect bone wound characteristics varied quite a lot and mixed different criteria, thus leading sometimes to conflicting results. In this context, the aim of our study is to clarify qualitative aspects of cut marks induced by sharp weapons on human bones. For that purpose, we analyzed bone samples via an original approach based on bone autofluorescence with an epifluorescence macroscope and compared it to previous existing methods. In this study, we used bone sections from human clavicles on which three different kinds of lesions were manually implemented, using different weapons. The bone wounds were analyzed by three different methodologies, light microscopy, scanning electron microscopy (SEM), and micro-computed tomography, and were compared with epifluorescence macroscopy. We paid attention more significantly to the aspect of walls and floor of the kerf, so as to conclude on the nature and distinguish between weapons used. Among all technologies used in this study, the most precise and efficient methods were epifluorescence macroscopy and SEM. Nonetheless, epifluorescence macroscopy is faster, cheaper, and more accessible than SEM. More significantly, this technique, which has the potential to accurately document the nature of the damage, is nondestructive, and could thus be highly useful in forensic science as anthropology.
Spallone, Aldo; Vidal, Roberto V.; Gonzales, Justo G.
2010-01-01
Objective: Pituitary adenomas invading the cavernous sinus represent a therapeutic challenge. Those tumors have been traditionally treated with incomplete surgical removal, observation and/ or adjunctive medical therapy, and radiotherapy. In relatively recent years, some authors have suggested a main direct surgical approach to cavernous sinus (CS) with the aim of complete removal of the adenoma, either by a modified trans-sphenoidal route, using or not an endoscopy-assisted approach, or by a transcranial direct approach. The latter has the advantage of allowing direct exposure of the lesion with a view of the surgical field unhindered by important neurovascular structures. Materials and Methods: We report a technical modification of the classical epidural approach for CS adenoma removal. This was used in 14 patients. Surgical technique included a fronto-orbito-zygomatic craniotomy with extradural anterior clinoidectomy, and intradural approach to the Hakuba’s triangle for intracavernous dissection. The tumors were removed under direct vision. Results: Total macroscopical removal was achieved in all but one case. This patient required postoperative radiation therapy as well as adjuvant dopaminergic regime for achieving control of preoperatively increased hormonal values. No other case required radiotherapy. Hormonal and/ or clinical control was also achieved in all the remaining cases. Out of the remaining 13 cases, all appeared to be tumor free at an average postoperative observation at 78 months (34 to 90 months). Significant surgical sequels were detected in only 1 case (persistent 3rd nerve palsy and moderate hemiparesis). Conclusions: This experience, though limited, would suggest that the transcranial limited CS exposure through the Hakuba’s triangle may allow adequate removal of intracavernous pituitary adenomas with very good long-term results and acceptable complication rate. PMID:20847907
NASA Astrophysics Data System (ADS)
Boiselet, Aurelien; Scotti, Oona; Lyon-Caen, Hélène
2014-05-01
The Corinth rift, Greece, is one of the regions with highest strain rates in the Euro-Mediterranean area and as such it has long been identified as a site of major importance for earthquake studies in Europe (20 years of research by the Corinth Rift Laboratory and 4 years of in-depth studies by the ANR-SISCOR project). This enhanced knowledge, acquired in particular, in the western part of the Gulf of Corinth, an area about 50 by 40 km, between the city of Patras to the west and the city of Aigion to the east, provides an excellent opportunity to compare fault-based and classical seismotectonic approaches currently used in seismic hazard assessment studies. A homogeneous earthquake catalogue was first constructed for the Greek territory based on two existing earthquake catalogues available for Greece (National Observatory of Athens and Thessaloniki). In spite of numerous documented damaging earthquakes, only a limited amount of macroseismic intensity data points are available in the existing databases for the damaging earthquakes affecting the west Corinth rift region. A re-interpretation of the macroseismic intensity field for numerous events was thus conducted, following an in-depth analysis of existing and newly found documentation (for details see Rovida et al. EGU2014-6346). In parallel, the construction of a comprehensive database of all relevant geological, geodetical and geophysical information (available in the literature and recently collected within the ANR-SISCOR project), allowed proposing rupture geometries for the different fault-systems identified in the study region. The combination of the new earthquake parameters and the newly defined fault geometries, together with the existing published paleoseismic data, allowed proposing a suite of rupture scenarios including the activation of multiple fault segments. The methodology used to achieve this goal consisted in setting up a logic tree that reflected the opinion of all the members of the ANR
Morgan, Simeon J; Paolini, Antonio G
2012-06-06
Acute animal preparations have been used in research prospectively investigating electrode designs and stimulation techniques for integration into neural auditory prostheses, such as auditory brainstem implants and auditory midbrain implants. While acute experiments can give initial insight to the effectiveness of the implant, testing the chronically implanted and awake animals provides the advantage of examining the psychophysical properties of the sensations induced using implanted devices. Several techniques such as reward-based operant conditioning, conditioned avoidance, or classical fear conditioning have been used to provide behavioral confirmation of detection of a relevant stimulus attribute. Selection of a technique involves balancing aspects including time efficiency (often poor in reward-based approaches), the ability to test a plurality of stimulus attributes simultaneously (limited in conditioned avoidance), and measure reliability of repeated stimuli (a potential constraint when physiological measures are employed). Here, a classical fear conditioning behavioral method is presented which may be used to simultaneously test both detection of a stimulus, and discrimination between two stimuli. Heart-rate is used as a measure of fear response, which reduces or eliminates the requirement for time-consuming video coding for freeze behaviour or other such measures (although such measures could be included to provide convergent evidence). Animals were conditioned using these techniques in three 2-hour conditioning sessions, each providing 48 stimulus trials. Subsequent 48-trial testing sessions were then used to test for detection of each stimulus in presented pairs, and test discrimination between the member stimuli of each pair. This behavioral method is presented in the context of its utilisation in auditory prosthetic research. The implantation of electrocardiogram telemetry devices is shown. Subsequent implantation of brain electrodes into the Cochlear
Petrone, Alessio; Cerezo, Javier; Ferrer, Francisco J Avila; Donati, Greta; Improta, Roberto; Rega, Nadia; Santoro, Fabrizio
2015-05-28
We study the absorption and emission electronic spectra in an aqueous solution of N-methyl-6-oxyquinolinium betaine (MQ), an interesting dye characterized by a large change of polarity and H-bond ability between the ground (S0) and the excited (S1) states. To that end we compare alternative approaches based either on explicit solvent models and density functional theory (DFT)/molecular-mechanics (MM) calculations or on DFT calculations on clusters models embedded in a polarizable continuum (PCM). In the first approach (ClMD), the spectrum is computed according to the classical Franck-Condon principle, from the dispersion of the time-dependent (TD)-DFT vertical transitions at selected snapshots of molecular dynamics (MD) on the initial state. In the cluster model (Qst) the spectrum is simulated by computing the quantum vibronic structure, estimating the inhomogeneous broadening from state-specific TD-DFT/PCM solvent reorganization energies. While both approaches provide absorption and emission spectral shapes in nice agreement with experiment, the Stokes shift is perfectly reproduced by Qst calculations if S0 and S1 clusters are selected on the grounds of the MD trajectory. Furthermore, Qst spectra better fit the experimental line shape, mostly in absorption. Comparison of the predictions of the two approaches is very instructive: the positions of Qst and ClMD spectra are shifted due to the different solvent models and the ClMD spectra are narrower than the Qst ones, because MD underestimates the width of the vibrational density of states of the high-frequency modes coupled to the electronic transition. On the other hand, both Qst and ClMD approaches highlight that the solvent has multiple and potentially opposite effects on the spectral width, so that the broadening due to solute-solvent vibrations and electrostatic interaction with bulk solvent is (partially) counterbalanced by a narrowing of the contribution due to the solute vibrational modes. Qst analysis
What classicality? Decoherence and Bohr's classical concepts
NASA Astrophysics Data System (ADS)
Schlosshauer, Maximilian; Camilleri, Kristian
2011-03-01
Niels Bohr famously insisted on the indispensability of what he termed "classical concepts." In the context of the decoherence program, on the other hand, it has become fashionable to talk about the "dynamical emergence of classicality" from the quantum formalism alone. Does this mean that decoherence challenges Bohr's dictum—for example, that classical concepts do not need to be assumed but can be derived? In this paper we'll try to shed some light down the murky waters where formalism and philosophy cohabitate. To begin, we'll clarify the notion of classicality in the decoherence description. We'll then discuss Bohr's and Heisenberg's take on the quantum—classical problem and reflect on different meanings of the terms "classicality" and "classical concepts" in the writings of Bohr and his followers. This analysis will allow us to put forward some tentative suggestions for how we may better understand the relation between decoherence-induced classicality and Bohr's classical concepts.
Si, Wei; Wu, Chang-Qin
2015-07-14
We explore an instantaneous decoherence correction (IDC) approach for the decoherence and energy relaxation in the quantum-classical dynamics of charge transport in organic semiconducting crystals. These effects, originating from environmental fluctuations, are essential ingredients of the carrier dynamics. The IDC is carried out by measurement-like operations in the adiabatic representation. While decoherence is inherent in the IDC, energy relaxation is taken into account by considering the detailed balance through the introduction of energy-dependent reweighing factors, which could be either Boltzmann (IDC-BM) or Miller-Abrahams (IDC-MA) type. For a non-diagonal electron-phonon coupling model, it is shown that IDC tends to enhance diffusion while energy relaxation weakens this enhancement. As expected, both the IDC-BM and IDC-MA achieve a near-equilibrium distribution at finite temperatures in the diffusion process, while in the Ehrenfest dynamics the electronic system tends to infinite temperature limit. The resulting energy relaxation times with the two kinds of factors lie in different regimes and exhibit different dependences on temperature, decoherence time, and electron-phonon coupling strength, due to different dominant relaxation processes.
NASA Astrophysics Data System (ADS)
Daneshmand, R. N.; Tavassoly, M. K.
2015-05-01
Following the approach of Solano et al (2003 Phys. Rev. Lett. 90 027903) we propose a scheme for a generation of a few classes of entangled (nonlinear) coherent states. To achieve this purpose, the interaction of a spatially narrow collection of two-level atoms with a quantized field in a high-Q factor cavity in the presence of a strong-driving classical field is studied. We perform appropriate Hamiltonians describing the atom-field interaction by focusing on two particular forms of intensity-dependent functions which are directly related to su(1, 1) and su(2) Lie algebras. It is shown that the dynamical evolution of the considered systems can generate bipartite, tripartite (nonlinear) and more complicated entangled states corresponding to the mentioned groups depending on the number of atoms in the cavity. In the processes of the abovementioned generation schemes, even and odd nonlinear coherent states are produced. In the end, in a particular circumstance with the two-mode quantized field we can turn easily from Jaynes-Cummings to anti-Jaynes-Cummings interactions which brings us to the maximally entangled number state. Finally, to quantify the degree of entanglement of the produced states, the measures of von Neumann and linear entropies are applied.
Si, Wei; Wu, Chang-Qin
2015-07-14
We explore an instantaneous decoherence correction (IDC) approach for the decoherence and energy relaxation in the quantum-classical dynamics of charge transport in organic semiconducting crystals. These effects, originating from environmental fluctuations, are essential ingredients of the carrier dynamics. The IDC is carried out by measurement-like operations in the adiabatic representation. While decoherence is inherent in the IDC, energy relaxation is taken into account by considering the detailed balance through the introduction of energy-dependent reweighing factors, which could be either Boltzmann (IDC-BM) or Miller-Abrahams (IDC-MA) type. For a non-diagonal electron-phonon coupling model, it is shown that IDC tends to enhance diffusion while energy relaxation weakens this enhancement. As expected, both the IDC-BM and IDC-MA achieve a near-equilibrium distribution at finite temperatures in the diffusion process, while in the Ehrenfest dynamics the electronic system tends to infinite temperature limit. The resulting energy relaxation times with the two kinds of factors lie in different regimes and exhibit different dependences on temperature, decoherence time, and electron-phonon coupling strength, due to different dominant relaxation processes.
Reexamining the Quantum-Classical Relation
NASA Astrophysics Data System (ADS)
Bokulich, Alisa
2008-10-01
1. Intertheoretic relations: are imperialism and isolationism our only options?; 2. Heisenberg's closed theories and pluralistic realism; 3. Dirac's open theories and the reciprocal correspondence principle; 4. Bohr's generalization of classical mechanics; 5. Semiclassical mechanics: putting quantum flesh on classical bones; 6. Can classical structures explain quantum phenomena?; 7. A structural approach to intertheoretic relations; References; Index.
Shakib, Farnaz A.; Hanna, Gabriel
2016-01-14
In a previous study [F. A. Shakib and G. Hanna, J. Chem. Phys. 141, 044122 (2014)], we investigated a model proton-coupled electron transfer (PCET) reaction via the mixed quantum-classical Liouville (MQCL) approach and found that the trajectories spend the majority of their time on the mean of two coherently coupled adiabatic potential energy surfaces. This suggested a need for mean surface evolution to accurately simulate observables related to ultrafast PCET processes. In this study, we simulate the time-dependent populations of the three lowest adiabatic states in the ET-PT (i.e., electron transfer preceding proton transfer) version of the same PCET model via the MQCL approach and compare them to the exact quantum results and those obtained via the fewest switches surface hopping (FSSH) approach. We find that the MQCL population profiles are in good agreement with the exact quantum results and show a significant improvement over the FSSH results. All of the mean surfaces are shown to play a direct role in the dynamics of the state populations. Interestingly, our results indicate that the population transfer to the second-excited state can be mediated by dynamics on the mean of the ground and second-excited state surfaces, as part of a sequence of nonadiabatic transitions that bypasses the first-excited state surface altogether. This is made possible through nonadiabatic transitions between different mean surfaces, which is the manifestation of coherence transfer in MQCL dynamics. We also investigate the effect of the strength of the coupling between the proton/electron and the solvent coordinate on the state population dynamics. Drastic changes in the population dynamics are observed, which can be understood in terms of the changes in the potential energy surfaces and the nonadiabatic couplings. Finally, we investigate the state population dynamics in the PT-ET (i.e., proton transfer preceding electron transfer) and concerted versions of the model. The PT
Shakib, Farnaz A; Hanna, Gabriel
2016-01-14
In a previous study [F. A. Shakib and G. Hanna, J. Chem. Phys. 141, 044122 (2014)], we investigated a model proton-coupled electron transfer (PCET) reaction via the mixed quantum-classical Liouville (MQCL) approach and found that the trajectories spend the majority of their time on the mean of two coherently coupled adiabatic potential energy surfaces. This suggested a need for mean surface evolution to accurately simulate observables related to ultrafast PCET processes. In this study, we simulate the time-dependent populations of the three lowest adiabatic states in the ET-PT (i.e., electron transfer preceding proton transfer) version of the same PCET model via the MQCL approach and compare them to the exact quantum results and those obtained via the fewest switches surface hopping (FSSH) approach. We find that the MQCL population profiles are in good agreement with the exact quantum results and show a significant improvement over the FSSH results. All of the mean surfaces are shown to play a direct role in the dynamics of the state populations. Interestingly, our results indicate that the population transfer to the second-excited state can be mediated by dynamics on the mean of the ground and second-excited state surfaces, as part of a sequence of nonadiabatic transitions that bypasses the first-excited state surface altogether. This is made possible through nonadiabatic transitions between different mean surfaces, which is the manifestation of coherence transfer in MQCL dynamics. We also investigate the effect of the strength of the coupling between the proton/electron and the solvent coordinate on the state population dynamics. Drastic changes in the population dynamics are observed, which can be understood in terms of the changes in the potential energy surfaces and the nonadiabatic couplings. Finally, we investigate the state population dynamics in the PT-ET (i.e., proton transfer preceding electron transfer) and concerted versions of the model. The PT
Omanović, Dario; Pižeta, Ivanka; Vukosav, Petra; Kovács, Elza; Frančišković-Bilinski, Stanislav; Tamás, János
2015-04-01
The distribution and speciation of elements along a stream subjected to neutralised acid mine drainage (NAMD) effluent waters (Mátra Mountain, Hungary; Toka stream) were studied by a multi-methodological approach: dissolved and particulate fractions of elements were determined by HR-ICPMS, whereas speciation was carried out by DGT, supported by speciation modelling performed by Visual MINTEQ. Before the NAMD discharge, the Toka is considered as a pristine stream, with averages of dissolved concentrations of elements lower than world averages. A considerable increase of element concentrations caused by effluent water inflow is followed by a sharp or gradual concentration decrease. A large difference between total and dissolved concentrations was found for Fe, Al, Pb, Cu, Zn and As in effluent water and at the first downstream site, with high correlation factors between elements in particulate fraction, indicating their common behaviour, governed by the formation of ferri(hydr)oxides (co)precipitates. In-situ speciation by the DGT technique revealed that Zn, Cd, Ni, Co, Mn and U were predominantly present as a labile, potentially bioavailable fraction (>90%). The formation of strong complexes with dissolved organic matter (DOM) resulted in a relatively low DGT-labile concentration of Cu (42%), while low DGT-labile concentrations of Fe (5%) and Pb (12%) were presumably caused by their existence in colloidal (particulate) fraction which is not accessible to DGT. Except for Fe and Pb, a very good agreement between DGT-labile concentrations and those predicted by the applied speciation model was obtained, with an average correlation factor of 0.96. This study showed that the in-situ DGT technique in combination with model-predicted speciation and classical analysis of samples could provide a reasonable set of data for the assessment of the water quality status (WQS), as well as for the more general study of overall behaviour of the elements in natural waters subjected
Semi-classical Electrodynamics
NASA Astrophysics Data System (ADS)
Lestone, John
2016-03-01
Quantum electrodynamics is complex and its associated mathematics can appear overwhelming for those not trained in this field. We describe semi-classical approaches that can be used to obtain a more intuitive physical feel for several QED processes including electro-statics, Compton scattering, pair annihilation, the anomalous magnetic moment, and the Lamb shift, that could be taught easily to undergraduate students. Any physicist who brings their laptop to the talk will be able to build spread sheets in less than 10 minutes to calculate g/2 =1.001160 and a Lamb shift of 1057 MHz.
Primitive Ontology and the Classical World
NASA Astrophysics Data System (ADS)
Allori, Valia
In this chapter, I present the common structure of quantum theories with a primitive ontology (PO), and discuss in what sense the classical world emerges from quantum theories as understood in this framework. In addition, I argue that the PO approach is better at analyzing the classical limit than the rival wave function ontology approach or any other approach in which the classical world is non-reductively "emergent:" even if the classical limit within this framework needs to be fully developed, the difficulties are technical rather than conceptual, while this is not true for the alternatives.
Classical photometry of prefractal surfaces.
Shkuratov, Yuriy; Petrov, Dmitriy; Videen, Gorden
2003-11-01
Using the scale invariance of classical photometry, we develop an approach to finding the photometric function of prefractal structures that form a random topography. The photometric function of the prefractal surfaces is found as the general solution of the resulting differential equation in partial derivatives. The function depends on two parameters: the number of hierarchical levels of the prefractal structures and the roughness parameter of the single-level generation. As a limiting case, the approach includes our previous theory that considered fractoids.
NASA Astrophysics Data System (ADS)
Azadegan, B.; Wagner, W.
2015-01-01
We present a Mathematica package for simulation of spectral-angular distributions and energy spectra of planar channeling radiation of relativistic electrons and positrons channeled along major crystallographic planes of a diamond-structure or tungsten single crystal. The program is based on the classical theory of channeling radiation which has been successfully applied to study planar channeling of light charged particles at energies higher than 100 MeV. Continuous potentials for different planes of diamond, Si, Ge and W single crystals are calculated using the Doyle-Turner approximation to the atomic scattering factor and taking thermal vibrations of the crystal atoms into account. Numerical methods are applied to solve the classical one-dimensional equation of motion. The code is designed to calculate the trajectories, velocities and accelerations of electrons (positrons) channeled by the planar continuous potential. In the framework of classical electrodynamics, these data allow realistic simulations of spectral-angular distributions and energy spectra of planar channeling radiation. Since the generated output is quantitative, the results of calculation may be useful, e.g., for setup configuration and crystal alignment in channeling experiments, for the study of the dependence of channeling radiation on the input parameters of particle beams with respect to the crystal orientation, but also for the simulation of positron production by means of pair creation what is mandatory for the design of efficient positron sources necessary in high-energy and collider physics. Although the classical theory of channeling is well established for long time, there is no adequate library program for simulation of channeling radiation up to now, which is commonly available, sufficiently simple and effective to employ and, therefore, of benefit as for special investigations as for a quick overview of basic features of this type of radiation.
ERIC Educational Resources Information Center
Boyer, Timothy H.
1985-01-01
The classical vacuum of physics is not empty, but contains a distinctive pattern of electromagnetic fields. Discovery of the vacuum, thermal spectrum, classical electron theory, zero-point spectrum, and effects of acceleration are discussed. Connection between thermal radiation and the classical vacuum reveals unexpected unity in the laws of…
ERIC Educational Resources Information Center
Matthews, Dorothy, Ed.
1979-01-01
The eight articles in this bulletin suggest methods of introducing classical literature into the English curriculum. Article titles are: "Ideas for Teaching Classical Mythology"; "What Novels Should High School Students Read?"; "Enlivening the Classics for Live Students"; "Poetry in Performance: The Value of Song and Oral Interpretation in…
NASA Astrophysics Data System (ADS)
Miller, William H.; Cotton, Stephen J.
2016-08-01
It is pointed out that the classical phase space distribution in action-angle (a-a) variables obtained from a Wigner function depends on how the calculation is carried out: if one computes the standard Wigner function in Cartesian variables (p, x), and then replaces p and x by their expressions in terms of a-a variables, one obtains a different result than if the Wigner function is computed directly in terms of the a-a variables. Furthermore, the latter procedure gives a result more consistent with classical and semiclassical theory—e.g., by incorporating the Bohr-Sommerfeld quantization condition (quantum states defined by integer values of the action variable) as well as the Heisenberg correspondence principle for matrix elements of an operator between such states—and has also been shown to be more accurate when applied to electronically non-adiabatic applications as implemented within the recently developed symmetrical quasi-classical (SQC) Meyer-Miller (MM) approach. Moreover, use of the Wigner function (obtained directly) in a-a variables shows how our standard SQC/MM approach can be used to obtain off-diagonal elements of the electronic density matrix by processing in a different way the same set of trajectories already used (in the SQC/MM methodology) to obtain the diagonal elements.
Hermeneutic reading of classic texts.
Koskinen, Camilla A-L; Lindström, Unni Å
2013-09-01
The purpose of this article is to broaden the understandinfg of the hermeneutic reading of classic texts. The aim is to show how the choice of a specific scientific tradition in conjunction with a methodological approach creates the foundation that clarifies the actual realization of the reading. This hermeneutic reading of classic texts is inspired by Gadamer's notion that it is the researcher's own research tradition and a clearly formulated theoretical fundamental order that shape the researcher's attitude towards texts and create the starting point that guides all reading, uncovering and interpretation. The researcher's ethical position originates in a will to openness towards what is different in the text and which constantly sets the researcher's preunderstanding and research tradition in movement. It is the researcher's attitude towards the text that allows the text to address, touch and arouse wonder. Through a flexible, lingering and repeated reading of classic texts, what is different emerges with a timeless value. The reading of classic texts is an act that may rediscover and create understanding for essential dimensions and of human beings' reality on a deeper level. The hermeneutic reading of classic texts thus brings to light constantly new possibilities of uncovering for a new envisioning and interpretation for a new understanding of the essential concepts and phenomena within caring science.
New Classical and New Keynesian Macroeconomics.
ERIC Educational Resources Information Center
Vane, Howard; Snowdon, Brian
1992-01-01
Summarizes underlying tenets and policy implications of new classical and new Keynesian macroeconomics. Compares new approaches with orthodox Keynesian and monetarist schools of thought. Identifies the fundamental difference between new classical and new Keynesian models as the assumption regarding the speed of wage and price adjustment following…
Teaching the Classics in High School.
ERIC Educational Resources Information Center
Shelley, Anne Crout
1998-01-01
Discusses why the classics can be difficult to teach in high schools. Offers suggestions for making difficult literature more approachable for high school students by scaffolding students' engagement with classic texts; building background knowledge; developing vocabulary; facilitating the reading of the text; and through enrichment an extension.…
NASA Astrophysics Data System (ADS)
Leblond, J. B.; Mottet, G.; Devaux, J. C.
THE RESPONSE of phase-transforming steels to variations of the applied stress (i.e. the ∑-term of the classical plastic strain rate Ė cp defined in Part I) is studied both theoretically and numerically for ideal-plastic individual phases. It is found theoretically that though the stress-strain curve contains no elastic portion, it is nevertheless initially tangent to the elastic line with slope equal to Young's modulus. Moreover an explicit formula for the beginning of the curve is derived for medium or high proportions of the harder phase, and a simple upper bound is given for the ultimate stress (maximum Von Mises stress). The finite element simulation confirms and completes these results, especially concerning the ultimate stress whose discrepancy with the theoretical upper bound is found to be maximum for low proportions of the harder phase. Based on these results, a complete model is proposed for the ∑-term of the classical plastic strain rate Ė cp in the case of ideal-plastic phases.
Schimpchen, Jan; Skorski, Sabrina; Nopp, Stephan; Meyer, Tim
2016-01-01
The aim of this study was to investigate the occurrence of repeated sprinting bouts in elite football. Furthermore, the construct validity of current tests assessing repeated-sprint ability (RSA) was analysed using information of sprinting sequences as they actually occurred during match-play. Sprinting behaviour in official competition was analysed for 19 games of the German national team between August 2012 and June 2014. A sprinting threshold was individually calculated based on the peak velocity reached during in-game sprinting. Players performed 17.2 ± 3.9 sprints per game and during the entire 19 games a total of 35 bouts of repeated sprinting (a minimum of three consecutive sprints with a recovery duration <30 s separating efforts). This averages one bout of repeated sprinting per player every 463 min. No general decrement in maximal sprinting speed was observed during bouts with up to five consecutive sprints. Results of the present study question the importance of RSA as it is classically defined. They indicate that shorter accelerations are more important in game-specific situations which do not reach speeds necessary to qualify them as sprints. The construct validity of classic tests of RSA in football is not supported by these observations.
NASA Astrophysics Data System (ADS)
Abd El-Wahab, N. H.; Abdel Rady, A. S.; Osman, Abdel-Nasser A.; Salah, Ahmed
2015-10-01
In this paper, a model is introduced to investigate the interaction between a three-level atom and one-mode of the radiation field. The atomic motion and the classical homogenous gravitational field are taken into consideration. For this purpose, we first introduce a set of new atomic operators obeying an su(3) algebraic structure to derive an effective Hamiltonian for the system under consideration. By solving the Schrödinger equation in the interaction picture, the exact solution is given when the atom and the field are initially prepared in excited state and coherent state, respectively. The influences of the gravity parameter on the collapses-revivals phenomena, the atomic momentum diffusion, the Mandel Q-parameter, the normal squeezing phenomena and the coherent properties for the considered system are examined. It is found that the gravity parameter has important effects on the properties of these phenomena.
Branislav, Rajić; Milivoj, Dopsaj; Abella, Carlos Pablos; Deval, Vicente Caratalla; Siniša, Karišik
2013-01-01
Background: The aim of this study is to verify the effects of the combined and classic training of different isometric rates of force development (RFD) parameters of legs. Materials and Methods: Three groups of female athletes was tested: Experimental group (N = 12), classically trained group (N = 11), and control group (N = 20) of athletes. The isometric “standing leg extension” and “Rise on Toes” tests were conducted to evaluate the maximal force, time necessary time to reach it and the RFD analyzed at 100 ms, 180 ms, 250 ms from the onset, and 50-100% of its maximal result. Results: The maximal RFD of legs and calves are dominant explosive parameters. Special training enhanced the RFD of calves of GROUPSPEC at 100 ms (P = 0.05), at 180 ms (P = 0.039), at 250 ms (P = 0.039), at 50% of the Fmax (P = 0.031) and the Fmax (P = 0.05). Domination of GROUPSPEC toward GROUPCLASS and GROUPCONTROL is in case of legs at 100 ms (P = 0.04); at 180 ms (P = 0.04); at 250 ms (P = 0.00); at 50% of the Fmax (P = 0.01) and at the Fmax (P = 0.00); in case of calves at 100 ms (P = 0.07); 180 ms (P = 0.001); at 250 ms (P = 0.00); at 50% of the Fmax (P = 0.00) and at Fmax (P = 0.000). Conclusion: Dominant explosive factors are maximal RFD of leg extensors and calves, and legs at 250ms. Specific training enhanced explosiveness of calves of GROUPSPEC general and partial domination of GROUPSPEC by 87% over GROUPCLASS, and 35% over GROUPCONTROL. PMID:24497853
Absolutely classical spin states
NASA Astrophysics Data System (ADS)
Bohnet-Waldraff, F.; Giraud, O.; Braun, D.
2017-01-01
We introduce the concept of "absolutely classical" spin states, in analogy to absolutely separable states of bipartite quantum systems. Absolutely classical states are states that remain classical (i.e., a convex sum of projectors on coherent states of a spin j ) under any unitary transformation applied to them. We investigate the maximal size of the ball of absolutely classical states centered on the maximally mixed state and derive a lower bound for its radius as a function of the total spin quantum number. We also obtain a numerical estimate of this maximal radius and compare it to the case of absolutely separable states.
NASA Astrophysics Data System (ADS)
Gheorghiu, Vlad; de Oliveira, Marcos C.; Sanders, Barry C.
2015-07-01
Quantum discord is the quantitative difference between two alternative expressions for bipartite mutual information, given respectively in terms of two distinct definitions for the conditional entropy. By constructing a stochastic model of shared states, classical discord can be similarly defined, quantifying the presence of some stochasticity in the measurement process. Therefore, discord can generally be understood as a quantification of the system's state disturbance due to local measurements, be it quantum or classical. We establish an operational meaning of classical discord in the context of state merging with noisy measurement and thereby show the quantum-classical separation in terms of a negative conditional entropy.
ERIC Educational Resources Information Center
Hansen, James
1978-01-01
Sponsored by a consortium of 30 American universities, Rome's Intercollegiate Center for Classical Studies offers a year of study to American undergraduate classics majors. Instructors are also American and normally stay only a year; teaching assistants are always ex-students of the center. Extensive field trips are an important part of the…
NASA Technical Reports Server (NTRS)
Valley, Lois
1989-01-01
The SPS product, Classic-Ada, is a software tool that supports object-oriented Ada programming with powerful inheritance and dynamic binding. Object Oriented Design (OOD) is an easy, natural development paradigm, but it is not supported by Ada. Following the DOD Ada mandate, SPS developed Classic-Ada to provide a tool which supports OOD and implements code in Ada. It consists of a design language, a code generator and a toolset. As a design language, Classic-Ada supports the object-oriented principles of information hiding, data abstraction, dynamic binding, and inheritance. It also supports natural reuse and incremental development through inheritance, code factoring, and Ada, Classic-Ada, dynamic binding and static binding in the same program. Only nine new constructs were added to Ada to provide object-oriented design capabilities. The Classic-Ada code generator translates user application code into fully compliant, ready-to-run, standard Ada. The Classic-Ada toolset is fully supported by SPS and consists of an object generator, a builder, a dictionary manager, and a reporter. Demonstrations of Classic-Ada and the Classic-Ada Browser were given at the workshop.
Classical/Non‐classical Polyoxometalate Hybrids
Santiago‐Schübel, Beatrix; Willbold, Sabine; Heß, Volkmar
2016-01-01
Abstract Two polyanions [SeI V 2PdII 4WVI 14O56H]11− and [SeI V 4PdII 4WVI 28O108H12]12− are the first hybrid polyoxometalates in which classical (Group 5/6 metal based) and non‐classical (late transition‐metal based) polyoxometalate units are joined. Requiring no supporting groups, this co‐condensation of polyoxotungstate and isopolyoxopalladate constituents also provides a logical link between POM‐PdII coordination complexes and the young subclass of polyoxopalladates. Solid‐state, solution, and gas‐phase studies suggest interesting specific reactivities for these hybrids and point to several potential derivatives and functionalization strategies. PMID:27617918
Diagrammar in classical scalar field theory
Cattaruzza, E.; Gozzi, E.; Francisco Neto, A.
2011-09-15
In this paper we analyze perturbatively a g{phi}{sup 4}classical field theory with and without temperature. In order to do that, we make use of a path-integral approach developed some time ago for classical theories. It turns out that the diagrams appearing at the classical level are many more than at the quantum level due to the presence of extra auxiliary fields in the classical formalism. We shall show that a universal supersymmetry present in the classical path-integral mentioned above is responsible for the cancelation of various diagrams. The same supersymmetry allows the introduction of super-fields and super-diagrams which considerably simplify the calculations and make the classical perturbative calculations almost 'identical' formally to the quantum ones. Using the super-diagrams technique, we develop the classical perturbation theory up to third order. We conclude the paper with a perturbative check of the fluctuation-dissipation theorem. - Highlights: > We provide the Feynman diagrams of perturbation theory for a classical field theory. > We give a super-formalism which links the quantum diagrams to the classical ones. > We check perturbatively the fluctuation-dissipation theorem.
Innovation: the classic traps.
Kanter, Rosabeth Moss
2006-11-01
Never a fad, but always in or out of fashion, innovation gets rediscovered as a growth enabler every half dozen years. Too often, though, grand declarations about innovation are followed by mediocre execution that produces anemic results, and innovation groups are quietly disbanded in cost-cutting drives. Each managerial generation embarks on the same enthusiastic quest for the next new thing. And each generation faces the same vexing challenges- most of which stem from the tensions between protecting existing revenue streams critical to current success and supporting new concepts that may be crucial to future success. In this article, Harvard Business School professor Rosabeth Moss Kanter reflects on the four major waves of innovation enthusiasm she's observed over the past 25 years. She describes the classic mistakes companies make in innovation strategy, process, structure, and skills assessment, illustrating her points with a plethora of real-world examples--including AT&T Worldnet, Timberland, and Ocean Spray. A typical strategic blunder is when managers set their hurdles too high or limit the scope of their innovation efforts. Quaker Oats, for instance, was so busy in the 1990s making minor tweaks to its product formulas that it missed larger opportunities in distribution. A common process mistake is when managers strangle innovation efforts with the same rigid planning, budgeting, and reviewing approaches they use in their existing businesses--thereby discouraging people from adapting as circumstances warrant. Companies must be careful how they structure fledgling entities alongside existing ones, Kanter says, to avoid a clash of cultures and agendas--which Arrow Electronics experienced in its attempts to create an online venture. Finally, companies commonly undervalue and underinvest in the human side of innovation--for instance, promoting individuals out of innovation teams long before their efforts can pay off. Kanter offers practical advice for avoiding
A Classical Science Transformed.
ERIC Educational Resources Information Center
Kovalevsky, Jean
1979-01-01
Describes how satellites and other tools of space technology have transformed classical geodesy into the science of space geodynamics. The establishment and the activities of the French Center for Geodynamic and Astronomical Research Studies (CERGA) are also included. (HM)
NASA Astrophysics Data System (ADS)
Frimmer, Martin; Novotny, Lukas
2014-10-01
Coherent control of a quantum mechanical two-level system is at the heart of magnetic resonance imaging, quantum information processing, and quantum optics. Among the most prominent phenomena in quantum coherent control are Rabi oscillations, Ramsey fringes, and Hahn echoes. We demonstrate that these phenomena can be derived classically by use of a simple coupled-harmonic-oscillator model. The classical problem can be cast in a form that is formally equivalent to the quantum mechanical Bloch equations with the exception that the longitudinal and the transverse relaxation times (T1 and T2) are equal. The classical analysis is intuitive and well suited for familiarizing students with the basic concepts of quantum coherent control, while at the same time highlighting the fundamental differences between classical and quantum theories.
NASA Technical Reports Server (NTRS)
Horzela, Andrzej; Kapuscik, Edward
1993-01-01
An alternative picture of classical many body mechanics is proposed. In this picture particles possess individual kinematics but are deprived from individual dynamics. Dynamics exists only for the many particle system as a whole. The theory is complete and allows to determine the trajectories of each particle. It is proposed to use our picture as a classical prototype for a realistic theory of confined particles.
Automatic target recognition via classical detection theory
NASA Astrophysics Data System (ADS)
Morgan, Douglas R.
1995-07-01
Classical Bayesian detection and decision theory applies to arbitrary problems with underlying probabilistic models. When the models describe uncertainties in target type, pose, geometry, surround, scattering phenomena, sensor behavior, and feature extraction, then classical theory directly yields detailed model-based automatic target recognition (ATR) techniques. This paper reviews options and considerations arising under a general Bayesian framework for model- based ATR, including approaches to the major problems of acquiring probabilistic models and of carrying out the indicated Bayesian computations.
NASA Astrophysics Data System (ADS)
Mandrà, Salvatore; Zhu, Zheng; Wang, Wenlong; Perdomo-Ortiz, Alejandro; Katzgraber, Helmut G.
2016-08-01
To date, a conclusive detection of quantum speedup remains elusive. Recently, a team by Google Inc. [V. S. Denchev et al., Phys. Rev. X 6, 031015 (2016), 10.1103/PhysRevX.6.031015] proposed a weak-strong cluster model tailored to have tall and narrow energy barriers separating local minima, with the aim to highlight the value of finite-range tunneling. More precisely, results from quantum Monte Carlo simulations as well as the D-Wave 2X quantum annealer scale considerably better than state-of-the-art simulated annealing simulations. Moreover, the D-Wave 2X quantum annealer is ˜108 times faster than simulated annealing on conventional computer hardware for problems with approximately 103 variables. Here, an overview of different sequential, nontailored, as well as specialized tailored algorithms on the Google instances is given. We show that the quantum speedup is limited to sequential approaches and study the typical complexity of the benchmark problems using insights from the study of spin glasses.
NASA Astrophysics Data System (ADS)
Pollock, Steven
2013-04-01
At most universities, including the University of Colorado, upper-division physics courses are taught using a traditional lecture approach that does not make use of many of the instructional techniques that have been found to improve student learning at the introductory level. We are transforming several upper-division courses using principles of active engagement and learning theory, guided by the results of observations, interviews, and analysis of student work at CU and elsewhere. In this talk I outline these transformations, including the development of faculty consensus learning goals, clicker questions, tutorials, modified homeworks, and more. We present evidence of the effectiveness of these transformations relative to traditional courses, based on student grades, interviews, and through research-based assessments of student conceptual mastery and student attitudes. Our results suggest that many of the tools that have been effective in introductory courses are effective for our majors, and that further research is warranted in the upper-division environment. (See www.colorado.edu/sei/departments/physics.htm for materials)
ERIC Educational Resources Information Center
Huddleston, Gregory H.
1993-01-01
Describes one teacher's methods for introducing to secondary English students the concepts of Classicism and Romanticism in relation to pictures of gardens, architecture, music, and literary works. Outlines how the unit leads to a writing assignment based on collected responses over time. (HB)
Classical Mythology. Fourth Edition.
ERIC Educational Resources Information Center
Morford, Mark P. O.; Lenardon, Robert J.
Designed for students with little or no background in classical literature, this book introduces the Greek and Roman myths of creation, myths of the gods, Greek sagas and local legends, and presents contemporary theories about the myths. Drawing on Homer, Hesiod, Pindar, Vergil, and others, the book provides many translations and paraphrases of…
ERIC Educational Resources Information Center
Karolides, Nicholas J., Ed.
1983-01-01
The articles in this journal issue suggest techniques for classroom use of literature that has "withstood the test of time." The titles of the articles and their authors are as follows: (1) "The Storytelling Connection for the Classics" (Mary Ellen Martin); (2) "Elizabeth Bennet: A Liberated Woman" (Geneva Marking);…
ERIC Educational Resources Information Center
Lum, Lydia
2005-01-01
America's few Black classics professors have overcome contempt and criticism to contribute a unique perspective to the study of the ancient world. Dr. Patrice Rankine, an associate professor from Purdue University, has grown used to the irony. As one of the few Black classicists teaching at an American university, he has drawn plenty of skepticism…
ERIC Educational Resources Information Center
Camic, Charles
2008-01-01
They seem the perfect bookends for the social psychologist's collection of "classics" of the field. Two volumes, nearly identical in shape and weight and exactly a century old in 2008--each professing to usher "social psychology" into the world as they both place the hybrid expression square in their titles but then proceed to stake out the field…
Children's Classics. Fifth Edition.
ERIC Educational Resources Information Center
Jordan, Alice M.
"Children's Classics," a 1947 article by Alice M. Jordan reprinted from "The Horn Book Magazine," examines the dynamics and appeal of some of the most famous books for young readers, including "Alice in Wonderland,""The Wind in the Willows,""Robinson Crusoe," and "Andersen's Fairy Tales." Paul Hein's annotated bibliography, a revision of Jordan's…
ERIC Educational Resources Information Center
Tighe, Mary Ann; Avinger, Charles
1994-01-01
Describes young adult novels that may prove to be classics of the genre. Discusses "The "Chocolate War" by Robert Cormier, "The Outsiders" by S. E. Hinton, "The Witch of Blackbird Pond" by Elizabeth George Speare, and "On Fortune's Wheel" by Cynthia Voight. (HB)
Observations of classical cepheids
NASA Technical Reports Server (NTRS)
Pel, J. W.
1980-01-01
The observations of classical Cepheids are reviewed. The main progress that has been made is summarized and some of the problems yet to be solved are discussed. The problems include color excesses, calibration of color, duplicity, ultraviolet colors, temperature-color relations, mass discrepancies, and radius determination.
Classical Demonstration of Polarization.
ERIC Educational Resources Information Center
Bauman, Robert P.; Moore, Dennis R.
1980-01-01
Presents a classical demonstration of polarization for high school students. The initial state of this model, which demonstrates the important concepts of the optical and quantum problems, was developed during the 1973 summer program on lecture demonstration at the U.S. Naval Academy. (HM)
Classical galactosaemia revisited.
Bosch, Annet M
2006-08-01
Classical galactosaemia (McKusick 230400) is an: autosomal recessive disorder of galactose metabolism, caused by a deficiency of the enzyme galactose-1-phosphate uridyltransferase (GALT; EC 2.7.712). Most patients present in the neonatal period, after ingestion of galactose, with jaundice, hepatosplenomegaly, hepatocellular insufficiency, food intolerance, hypoglycaemia, renal tubular dysfunction, muscle hypotonia, sepsis and cataract. The gold standard for diagnosis of classical galactosaemia is measurement of GALT activity in erythrocytes. Gas-chromatographic determination of urinary sugars and sugar alcohols demonstrates elevated concentrations of galactose and galactitol. The only therapy for patients with classical galactosaemia is a galactose-restricted diet, and initially all galactose must be removed from the diet as soon as the diagnosis is suspected. After the neonatal period, a lactose-free diet is advised in most countries, without restriction of galactose-containing fruit and vegetables. In spite of the strict diet, long-term complications such as retarded mental development, verbal dyspraxia, motor abnormalities and hypergonadotrophic hypogonadism are frequently seen in patients with classical galactosaemia. It has been suggested that these complications may result from endogenous galactose synthesis or from abnormal galactosylation. Novel therapeutic strategies, aiming at the prevention of galactose 1-phosphate production, should be developed. In the meantime, the follow-up protocol for patients with GALT deficiency should focus on early detection, evaluation and, if possible, early intervention in problems of motor, speech and cognitive development.
Quantization of soluble classical constrained systems
Belhadi, Z.; Menas, F.; Bérard, A.; Mohrbach, H.
2014-12-15
The derivation of the brackets among coordinates and momenta for classical constrained systems is a necessary step toward their quantization. Here we present a new approach for the determination of the classical brackets which does neither require Dirac’s formalism nor the symplectic method of Faddeev and Jackiw. This approach is based on the computation of the brackets between the constants of integration of the exact solutions of the equations of motion. From them all brackets of the dynamical variables of the system can be deduced in a straightforward way.
Classical and Contemporary Approaches for Moral Development
ERIC Educational Resources Information Center
Cam, Zekeriya; Seydoogullari, Sedef; Cavdar, Duygu; Cok, Figen
2012-01-01
Most of the information in the moral development literature depends on Theories of Piaget and Kohlberg. The theoretical contribution by Gilligan and Turiel are not widely known and not much resource is available in Turkish. For this reason introducing and discussing the theories of Gilligan and Turiel and more comprehensive perspective for moral…
NASA Astrophysics Data System (ADS)
Iselin, F. Christoph
1997-02-01
Exchange of data and algorithms among accelerator physics programs is difficult because of unnecessary differences in input formats and internal data structures. To alleviate these problems a C++ class library called CLASSIC (Class Library for Accelerator System Simulation and Control) is being developed with the goal to provide standard building blocks for computer programs used in accelerator design. It includes modules for building accelerator lattice structures in computer memory using a standard input language, a graphical user interface, or a programmed algorithm. It also provides simulation algorithms. These can easily be replaced by modules which communicate with the control system of the accelerator. Exchange of both data and algorithm between different programs using the CLASSIC library should present no difficulty.
Moennig, V; Becher, P; Beer, M
2013-01-01
Classical swine fever is a serious and economically important transboundary disease threatening pig production globally. The infection may occur in backyard pigs, feral pig populations and domestic pigs. Whereas there are proven control strategies for the latter pig population, control in backyard pigs with poor biosecurity settings or in wild boar populations of high density still poses a problem in some parts of the world. Laboratory diagnostic methods, efficacious vaccines and contingency plans are in place in most industrialised countries. So far modified live vaccines (MLV) are still the first choice for rapid and reliable immune protection. Since antibodies elicited by conventional MLV cannot be distinguished from antibodies after natural infection, considerable efforts are put into the development of a live marker vaccine accompanied by a serological test. Nevertheless, some remaining gaps with respect to the diagnosis of and vaccination against classical swine fever have been identified.
Classical Vs. Superfluid Turbulence
NASA Astrophysics Data System (ADS)
Roche, P.-E.
2008-11-01
Thanks to a zero-viscosity, superfluids offer a unique testing ground for hydrodynamic models, in particular for turbulence ones. In Kolmogorov's turbulence model, viscosity is well known to damp the kinetic energy of the smallest eddies, and thus to introduce a cut-off at one end of the turbulent cascade. Significant differences between this ``classical'' turbulence and the turbulence of a superfluid are therefore expected, but --surprisingly- most experiments rather evidenced strong similarities. We will give an overview of a set of experiments designed to compare in details the classical versus superfluid turbulences, up to a record mass flow of superfluid (700g/s of He @ 1.6K). Then, we will focus on some unexpected vorticity measurements, which can be interpreted assuming that the superfluid vortices are passively advected by the largest scales of the flow, in contrast with the ``classical'' turbulence counterpart. Numerical simulations -based on regular DNS- will be presented to complete this interpretation. In collaboration with C. Barenghi, University of Newcastle; B. Castaing and E. Levèque, ENSL, Lyon; S. David, IEF, CNRS, Orsay; B. Rousset, SBT/CEA, Grenoble; and P. Tabeling, H. Willaime MMN, ESPCI, Paris.
Entanglement with classical fields
Lee, K.F.; Thomas, J.E.
2004-05-01
We experimentally demonstrate a simple classical-field optical heterodyne method which employs postselection to reproduce the polarization correlations of a four-particle entangled state. We give a heuristic argument relating this method to the measurement of multiple quantum fields by correlated homodyne detection. We suggest that using multiple classical fields and postselection, one can reproduce the polarization correlations obtained in quantum experiments which employ multiple single-photon sources and linear optics to prepare multiparticle entangled states. Our experimental scheme produces four spatially separated beams which are separately detected by mixing with four independent optical local oscillators (LO) of variable polarization. Analog multiplication of the four beat signals enables projection onto a four-particle polarization-state basis. Appropriate band pass filtering is used to produce a signal proportional to the projections of the maximally entangled four-field polarization state, H{sub 1})H{sub 2})H{sub 3})H{sub 4})+V{sub 1})V{sub 2})V{sub 3})V{sub 4}), onto the product of the four LO polarizations. Since the data from multiple observers is combined prior to postselection, this method does not constitute a test of nonlocality. However, we reproduce the polarization correlations of the 32 elements in the truth table from the quantum mechanical Greenberger-Horne-Zeilinger experiments on the violation of local realism. We also demonstrate a form of classical entanglement swapping in a four-particle basis.
Exchange potentials for semi-classical electrons.
Herzfeld, Judith; Ekesan, Solen
2016-11-09
Semi-classical electrons offer access to efficient and intuitive simulations of chemical reactions. As for any treatment of fermions, the greatest difficulty is in accounting for anti-symmetry effects. Semi-classical efforts to-date either reference Slater-determinants from ab initio treatments or adopt a heuristic approach inspired by density functional treatments. Here we revisit the problem with a combined approach. We conclude that semi-classical electrons need to reference a non-conventional wave function and find that (1) contrary to earlier suppositions, contributions from the electrostatic terms in the Hamiltonian are of similar magnitude to those from the kinetic terms and (2) the former point to a need to supplement pair potentials with 3-body potentials. The first result explains features of reported heuristic potentials, and the second provides a firm footing for extending the transferability of potentials across a wider range of elements and bonding scenarios.
Machian classical and semiclassical emergent time
NASA Astrophysics Data System (ADS)
Anderson, Edward
2014-01-01
Classical and semiclassical schemes are presented that are timeless at the primary level and recover time from Mach’s ‘time is to be abstracted from change’ principle at the emergent secondary level. The semiclassical scheme is a Machian variant of the semiclassical approach to the problem of time in quantum gravity. The classical scheme is Barbour’s, cast here explicitly as the classical precursor of the semiclassical approach. Thus the two schemes have been married up, as equally-Machian and necessarily distinct, since the latter’s timestandard is abstracted in part from quantum change. I provide perturbative schemes for these in which the timefunction is to be determined rather than assumed. This paper is useful modelling as regards the Halliwell-Hawking arena for the quantum origin of the inhomogeneous cosmological fluctuations.
Quantum and Classical Electrostatics Among Atoms
NASA Astrophysics Data System (ADS)
Doerr, T. P.; Obolensky, O. I.; Ogurtsov, A. Y.; Yu, Yi-Kuo
Quantum theory has been unquestionably successful at describing physics at the atomic scale. However, it becomes more difficult to apply as the system size grows. On the other hand, classical physics breaks down at sufficiently short length scales but is clearly correct at larger distances. The purpose of methods such as QM/MM is to gain the advantages of both quantum and classical regimes: quantum theory should provide accuracy at the shortest scales, and classical theory, with its somewhat more tractable computational demands, allows results to be computed for systems that would be inaccessible with a purely quantum approach. This strategy will be most effective when one knows with good accuracy the length scale at which quantum calculations are no longer necessary and classical calculations are sufficient. To this end, we have performed both classical and quantum calculations for systems comprising a small number of atoms for which experimental data is also available. The classical calculations are fully exact; the quantum calculations are at the MP4(SDTQ)/aug-cc-pV5Z and CCSD(T)/aug-cc-pV5Z levels. The precision of both sets of calculations along with the existence of experimental results allows us to draw conclusions about the range of utility of the respective calculations. This research was supported by the Intramural Research Program of the NIH, NLM and utilized the computational resources of the NIH HPC Biowulf cluster.
Hoffmann, Sabine; Rage, Estelle; Laurier, Dominique; Laroche, Pierre; Guihenneuc, Chantal; Ancelet, Sophie
2017-02-01
Many occupational cohort studies on underground miners have demonstrated that radon exposure is associated with an increased risk of lung cancer mortality. However, despite the deleterious consequences of exposure measurement error on statistical inference, these analyses traditionally do not account for exposure uncertainty. This might be due to the challenging nature of measurement error resulting from imperfect surrogate measures of radon exposure. Indeed, we are typically faced with exposure uncertainty in a time-varying exposure variable where both the type and the magnitude of error may depend on period of exposure. To address the challenge of accounting for multiplicative and heteroscedastic measurement error that may be of Berkson or classical nature, depending on the year of exposure, we opted for a Bayesian structural approach, which is arguably the most flexible method to account for uncertainty in exposure assessment. We assessed the association between occupational radon exposure and lung cancer mortality in the French cohort of uranium miners and found the impact of uncorrelated multiplicative measurement error to be of marginal importance. However, our findings indicate that the retrospective nature of exposure assessment that occurred in the earliest years of mining of this cohort as well as many other cohorts of underground miners might lead to an attenuation of the exposure-risk relationship. More research is needed to address further uncertainties in the calculation of lung dose, since this step will likely introduce important sources of shared uncertainty.
Un-renormalized classical electromagnetism
Ibison, Michael . E-mail: ibison@earthtech.org
2006-02-15
This paper follows in the tradition of direct-action versions of electromagnetism having the aim of avoiding a balance of infinities wherein a mechanical mass offsets an infinite electromagnetic mass so as to arrive at a finite observed value. However, the direct-action approach ultimately failed in that respect because its initial exclusion of self-action was later found to be untenable in the relativistic domain. Pursing the same end, this paper examines instead a version of electromagnetism wherein mechanical action is excluded and self-action is retained. It is shown that the resulting theory is effectively interacting due to the presence of infinite forces. A vehicle for the investigation is a pair of classical point charges in a positronium-like arrangement for which the orbits are found to be self-sustaining and naturally quantized.
GALK inhibitors for classic galactosemia.
Lai, Kent; Boxer, Matthew B; Marabotti, Anna
2014-06-01
Classic galactosemia is an inherited metabolic disease for which, at present, no therapy is available apart from galactose-restricted diet. However, the efficacy of the diet is questionable, since it is not able to prevent the insurgence of chronic complications later in life. In addition, it is possible that dietary restriction itself could induce negative side effects. Therefore, there is a need for an alternative therapeutic approach that can avert the manifestation of chronic complications in the patients. In this review, the authors describe the development of a novel class of pharmaceutical agents that target the production of a toxic metabolite, galactose-1-phosphate, considered as the main culprit for the cause of the complications, in the patients.
Decoherence, chaos, the quantum and the classical
Zurek, W.H.; Paz, J.P.
1994-04-01
The key ideas of the environment-induced decoherence approach are reviewed. Application of decoherence to the transition from quantum to classical in open quantum systems with chaotic classical analogs is described. The arrow of time is, in this context, a result of the information loss to the correlations with the environment. The asymptotic rate of entropy production (which is reached quickly, on the dynamical timescale) is independent of the details of the coupling of the quantum system to the environment, and is set by the Lyapunov exponents. We also briefly outline the existential interpretation of quantum mechanics, justifying the slogan ``No information without representation.``
Communication: quantum dynamics in classical spin baths.
Sergi, Alessandro
2013-07-21
A formalism for studying the dynamics of quantum systems embedded in classical spin baths is introduced. The theory is based on generalized antisymmetric brackets and predicts the presence of open-path off-diagonal geometric phases in the evolution of the density matrix. The weak coupling limit of the equation can be integrated by standard algorithms and provides a non-Markovian approach to the computer simulation of quantum systems in classical spin environments. It is expected that the theory and numerical schemes presented here have a wide applicability.
Fano Interference in Classical Oscillators
ERIC Educational Resources Information Center
Satpathy, S.; Roy, A.; Mohapatra, A.
2012-01-01
We seek to illustrate Fano interference in a classical coupled oscillator by using classical analogues of the atom-laser interaction. We present an analogy between the dressed state picture of coherent atom-laser interaction and a classical coupled oscillator. The Autler-Townes splitting due to the atom-laser interaction is analogous to the…
Classical Trajectories and Quantum Spectra
NASA Technical Reports Server (NTRS)
Mielnik, Bogdan; Reyes, Marco A.
1996-01-01
A classical model of the Schrodinger's wave packet is considered. The problem of finding the energy levels corresponds to a classical manipulation game. It leads to an approximate but non-perturbative method of finding the eigenvalues, exploring the bifurcations of classical trajectories. The role of squeezing turns out decisive in the generation of the discrete spectra.
Perspective: Quantum or classical coherence?
Miller, William H
2012-06-07
Some coherence effects in chemical dynamics are described correctly by classical mechanics, while others only appear in a quantum treatment--and when these are observed experimentally it is not always immediately obvious whether their origin is classical or quantum. Semiclassical theory provides a systematic way of adding quantum coherence to classical molecular dynamics and thus provides a useful way to distinguish between classical and quantum coherence. Several examples are discussed which illustrate both cases. Particularly interesting is the situation with electronically non-adiabatic processes, where sometimes whether the coherence effects are classical or quantum depends on what specific aspects of the process are observed.
Supersymmetry in classical mechanics
NASA Astrophysics Data System (ADS)
Suen, W. M.; Wong, C. W.; Young, K.
2000-06-01
The concept of supersymmetry extended to classical mechanics relates one-parameter families of Hamiltonians H( ξ, x, p)= p2+ V( ξ, x), such that the mapping from the phase space of H( ξ1, x, p) to that of H( ξ2, x, p) preserves time-evolution and conserves total energy; as a result, equal-energy periodic orbits in the two have the same period. While t-evolution is a contact transformation generated by H, ξ-evolution is a generalized contact transformation generated by a function K, and preserves phase volume except for a point sink (source) as ξ increases (decreases). Closed-form solutions of ξ-evolution include several well-known examples.
NASA Astrophysics Data System (ADS)
Boyer, T. H.
1985-08-01
The history of vacuum concepts is reviewed, noting that no way is known to physically produce a true void. Even at absolute zero, a pattern of electromagnetic wave fluctuations are still present. The fluctuations are called zero-point radiation (ZPR). To be invariant to Lorentz transformation, ZPR has a spectral intensity proportional to the cube of each frequency. ZPR does not change in response to compression and produces a force between objects that is inversely proportional to the 4th power of the separation distance. The ZPR scale value has been measured to be one-half of the Planck constant, and is the measure of the energy of a harmonic oscillator, such as the electron, in a vacuum. Finally, since gravitational accelerations always occur in the physical space, a minimum thermal radiation can also be found for the vacuum, implying that a fixed relationship exists between thermal radiation and the classical vacuum.
Supersymmetric classical cosmology
Escamilla-Rivera, Celia; Obregón, Octavio; Ureña-López, L. Arturo E-mail: octavio@fisica.ugto.mx
2010-12-01
In this work a supersymmetric cosmological model is analyzed in which we consider a general superfield action of a homogeneous scalar field supermultiplet interacting with the scale factor in a supersymmetric FRW model. There appear fermionic superpartners associated with both the scale factor and the scalar field, and classical equations of motion are obtained from the super-Wheeler-DeWitt equation through the usual WKB method. The resulting supersymmetric Einstein-Klein-Gordon equations contain extra radiation and stiff matter terms, and we study their solutions in flat space for different scalar field potentials. The solutions are compared to the standard case, in particular those corresponding to the exponential potential, and their implications for the dynamics of the early Universe are discussed in turn.
NASA Astrophysics Data System (ADS)
Sbisà, Fulvio
2015-01-01
The aim of these notes is to provide a self-contained review of why it is generically a problem when a solution of a theory possesses ghost fields among the perturbation modes. We define what a ghost field is and we show that its presence is associated with a classical instability whenever the ghost field interacts with standard fields. We then show that the instability is more severe at quantum level, and that perturbative ghosts can exist only in low energy effective theories. However, if we do not consider very ad hoc choices, compatibility with observational constraints implies that low energy effective ghosts can exist only at the price of giving up Lorentz invariance or locality above the cut-off, in which case the cut-off has to be much lower that the energy scales we currently probe in particle colliders. We also comment on the possible role of extra degrees of freedom which break Lorentz invariance spontaneously.
Nechansky, A; Szolar, O H J; Siegl, P; Zinoecker, I; Halanek, N; Wiederkum, S; Kircheis, R
2009-05-01
The fully humanized Lewis-Y carbohydrate specific monoclonal antibody (mAb) IGN311 is currently tested in a passive immunotherapy approach in a clinical phase I trail and therefore regulatory requirements demand qualified assays for product analysis. To demonstrate the functionality of its Fc-region, the capacity of IGN311 to mediate complement dependent cytotoxicity (CDC) against human breast cancer cells was evaluated. The "classical" radioactive method using chromium-51 and a FACS-based assay were established and qualified according to ICH guidelines. Parameters evaluated were specificity, response function, bias, repeatability (intra-day precision), intermediate precision (operator-time different), and linearity (assay range). In the course of a fully nested design, a four-parameter logistic equation was identified as appropriate calibration model for both methods. For the radioactive assay, the bias ranged from -6.1% to -3.6%. The intermediate precision for future means of duplicate measurements revealed values from 12.5% to 15.9% and the total error (beta-expectation tolerance interval) of the method was found to be <40%. For the FACS-based assay, the bias ranged from -8.3% to 0.6% and the intermediate precision for future means of duplicate measurements revealed values from 4.2% to 8.0%. The total error of the method was found to be <25%. The presented data demonstrate that the FACS-based CDC is more accurate than the radioactive assay. Also, the elimination of radioactivity and the 'real-time' counting of apoptotic cells further justifies the implementation of this method which was subsequently applied for testing the influence of storage at 4 degrees C and 25 degrees C ('stability testing') on the potency of IGN311 drug product. The obtained results demonstrate that the qualified functional assay represents a stability indicating test method.
Nonlinear atom interferometer surpasses classical precision limit.
Gross, C; Zibold, T; Nicklas, E; Estève, J; Oberthaler, M K
2010-04-22
Interference is fundamental to wave dynamics and quantum mechanics. The quantum wave properties of particles are exploited in metrology using atom interferometers, allowing for high-precision inertia measurements. Furthermore, the state-of-the-art time standard is based on an interferometric technique known as Ramsey spectroscopy. However, the precision of an interferometer is limited by classical statistics owing to the finite number of atoms used to deduce the quantity of interest. Here we show experimentally that the classical precision limit can be surpassed using nonlinear atom interferometry with a Bose-Einstein condensate. Controlled interactions between the atoms lead to non-classical entangled states within the interferometer; this represents an alternative approach to the use of non-classical input states. Extending quantum interferometry to the regime of large atom number, we find that phase sensitivity is enhanced by 15 per cent relative to that in an ideal classical measurement. Our nonlinear atomic beam splitter follows the 'one-axis-twisting' scheme and implements interaction control using a narrow Feshbach resonance. We perform noise tomography of the quantum state within the interferometer and detect coherent spin squeezing with a squeezing factor of -8.2 dB (refs 11-15). The results provide information on the many-particle quantum state, and imply the entanglement of 170 atoms.
Population structure of the Classic period Maya.
Scherer, Andrew K
2007-03-01
This study examines the population structure of Classic period (A.D. 250-900) Maya populations through analysis of odontometric variation of 827 skeletons from 12 archaeological sites in Mexico, Guatemala, Belize, and Honduras. The hypothesis that isolation by distance characterized Classic period Maya population structure is tested using Relethford and Blangero's (Hum Biol 62 (1990) 5-25) approach to R matrix analysis for quantitative traits. These results provide important biological data for understanding ancient Maya population history, particularly the effects of the competing Tikal and Calakmul hegemonies on patterns of lowland Maya site interaction. An overall F(ST) of 0.018 is found for the Maya area, indicating little among-group variation for the Classic Maya sites tested. Principal coordinates plots derived from the R matrix analysis show little regional patterning in the data, though the geographic outliers of Kaminaljuyu and a pooled Pacific Coast sample did not cluster with the lowland Maya sites. Mantel tests comparing the biological distance matrix to a geographic distance matrix found no association between genetic and geographic distance. In the Relethford-Blangero analysis, most sites possess negative or near-zero residuals, indicating minimal extraregional gene flow. The exceptions were Barton Ramie, Kaminaljuyu, and Seibal. A scaled R matrix analysis clarifies that genetic drift is a consideration for understanding Classic Maya population structure. All results indicate that isolation by distance does not describe Classic period Maya population structure.
Non-Classical Congenital Adrenal Hyperplasia in Childhood
Kurtoğlu, Selim; Hatipoğlu, Nihal
2017-01-01
Congenital adrenal hyperplasia (CAH) is classified as classical CAH and non-classical CAH (NCCAH). In the classical type, the most severe form comprises both salt-wasting and simple virilizing forms. In the non-classical form, diagnosis can be more confusing because the patient may remain asymptomatic or the condition may be associated with signs of androgen excess in the postnatal period or in the later stages of life. This review paper will include information on clinical findings, symptoms, diagnostic approaches, and treatment modules of NCCAH. PMID:27354284
Grassmannization of classical models
NASA Astrophysics Data System (ADS)
Pollet, Lode; Kiselev, Mikhail N.; Prokof'ev, Nikolay V.; Svistunov, Boris V.
2016-11-01
Applying Feynman diagrammatics to non-fermionic strongly correlated models with local constraints might seem generically impossible for two separate reasons: (i) the necessity to have a Gaussian (non-interacting) limit on top of which the perturbative diagrammatic expansion is generated by Wick’s theorem, and (ii) Dyson’s collapse argument implying that the expansion in powers of coupling constant is divergent. We show that for arbitrary classical lattice models both problems can be solved/circumvented by reformulating the high-temperature expansion (more generally, any discrete representation of the model) in terms of Grassmann integrals. Discrete variables residing on either links, plaquettes, or sites of the lattice are associated with the Grassmann variables in such a way that the partition function (as well as all correlation functions) of the original system and its Grassmann-field counterpart are identical. The expansion of the latter around its Gaussian point generates Feynman diagrams. Our work paves the way for studying lattice gauge theories by treating bosonic and fermionic degrees of freedom on equal footing.
Extended symmetrical classical electrodynamics.
Fedorov, A V; Kalashnikov, E G
2008-03-01
In this paper, we discuss a modification of classical electrodynamics in which "ordinary" point charges are absent. The modified equations contain additional terms describing the induced charges and currents. The densities of the induced charges and currents depend on the vector k and the vectors of the electromagnetic field, E and B . It is shown that the vectors E and B can be defined in terms of two four-potentials and the components of k are the components of a four-tensor of the third rank. The Lagrangian of the modified electrodynamics is defined. The conditions are derived at which only one four-potential determines the behavior of the electromagnetic field. It is also shown that static modified electrodynamics can describe the electromagnetic field in the inner region of an electric monopole. In the outer region of the electric monopole the electric field is governed by the Maxwell equations. It follows from boundary conditions at the interface between the inner and outer regions of the monopole that the vector k has a discrete spectrum. The electric and magnetic fields, energy, and angular momentum of the monopole are found for different eigenvalues of k .
Making Classical Conditioning Understandable through a Demonstration Technique.
ERIC Educational Resources Information Center
Gibb, Gerald D.
1983-01-01
One lemon, an assortment of other fruits and vegetables, a tennis ball, and a Galvanic Skin Response meter are needed to implement this approach to teaching about classical conditioning in introductory psychology courses. (RM)
NASA Technical Reports Server (NTRS)
2007-01-01
M51, whose name comes from being the 51st entry in Charles Messier's catalog, is considered to be one of the classic examples of a spiral galaxy. At a distance of about 30 million light-years from Earth, it is also one of the brightest spirals in the night sky. A composite image of M51, also known as the Whirlpool Galaxy, shows the majesty of its structure in a dramatic new way through several of NASA's orbiting observatories. X-ray data from NASA's Chandra X-ray Observatory reveals point-like sources (purple) that are black holes and neutron stars in binary star systems. Chandra also detects a diffuse glow of hot gas that permeates the space between the stars. Optical data from the Hubble Space Telescope (green) and infrared emission from the Spitzer Space Telescope (red) both highlight long lanes in the spiral arms that consist of stars and gas laced with dust. A view of M51 with the Galaxy Evolution Explorer telescope shows hot, young stars that produce lots of ultraviolet energy (blue).
The textbook spiral structure is thought be the result of an interaction M51 is experiencing with its close galactic neighbor, NGC 5195, which is seen just above. Some simulations suggest M51's sharp spiral shape was partially caused when NGC 5195 passed through its main disk about 500 million years ago. This gravitational tug of war may also have triggered an increased level of star formation in M51. The companion galaxy's pull would be inducing extra starbirth by compressing gas, jump-starting the process by which stars form.
Semi-classical methods in nuclear physics
NASA Astrophysics Data System (ADS)
Brink, David M.
These lecture notes present an introduction to some semi-classical techniques which have applications in nuclear physics. Topics discussed include the WKB method, approaches based on the Feynman path integral, the Gutzwiller trace formula for level density fluctuations and the Thomas-Fermi approximation and the Vlasov equation for many-body problems. There are applications to heavy ion fusion reactions, bremsstrahlung emission in alpha decay and nuclear response functions.
Pembrolizumab in classical Hodgkin's lymphoma.
Maly, Joseph; Alinari, Lapo
2016-09-01
Pembrolizumab is a humanized monoclonal antibody directed against programmed cell death protein 1 (PD-1), a key immune-inhibitory molecule expressed on T cells and implicated in CD4+ T-cell exhaustion and tumor immune-escape mechanisms. Classical Hodgkin's lymphoma (cHL) is a unique B-cell malignancy in the sense that malignant Reed-Sternberg (RS) cells represent a small percentage of cells within an extensive immune cell infiltrate. PD-1 ligands are upregulated on RS cells as a consequence of both chromosome 9p24.1 amplification and Epstein-Barr virus infection and by interacting with PD-1 promote an immune-suppressive effect. By augmenting antitumor immune response, pembrolizumab and nivolumab, another monoclonal antibody against PD-1, have shown significant activity in patients with relapsed/refractory cHL as well as an acceptable toxicity profile with immune-related adverse events that are generally manageable. In this review, we explore the rationale for targeting PD-1 in cHL, review the clinical trial results supporting the use of checkpoint inhibitors in this disease, and present future directions for investigation in which this approach may be used.
Dynamical Symmetries in Classical Mechanics
ERIC Educational Resources Information Center
Boozer, A. D.
2012-01-01
We show how symmetries of a classical dynamical system can be described in terms of operators that act on the state space for the system. We illustrate our results by considering a number of possible symmetries that a classical dynamical system might have, and for each symmetry we give examples of dynamical systems that do and do not possess that…
Operator Formulation of Classical Mechanics.
ERIC Educational Resources Information Center
Cohn, Jack
1980-01-01
Discusses the construction of an operator formulation of classical mechanics which is directly concerned with wave packets in configuration space and is more similar to that of convential quantum theory than other extant operator formulations of classical mechanics. (Author/HM)
Teaching and Demonstrating Classical Conditioning.
ERIC Educational Resources Information Center
Sparrow, John; Fernald, Peter
1989-01-01
Discusses classroom demonstrations of classical conditioning and notes tendencies to misrepresent Pavlov's procedures. Describes the design and construction of the conditioner that is used for demonstrating classical conditioning. Relates how students experience conditioning, generalization, extinction, discrimination, and spontaneous recovery.…
Fertility preservation in female classic galactosemia patients.
van Erven, Britt; Gubbels, Cynthia S; van Golde, Ron J; Dunselman, Gerard A; Derhaag, Josien G; de Wert, Guido; Geraedts, Joep P; Bosch, Annet M; Treacy, Eileen P; Welt, Corrine K; Berry, Gerard T; Rubio-Gozalbo, M Estela
2013-07-16
Almost every female classic galactosemia patient develops primary ovarian insufficiency (POI) as a diet-independent complication of the disease. This is a major concern for patients and their parents, and physicians are often asked about possible options to preserve fertility. Unfortunately, there are no recommendations on fertility preservation in this group. The unique pathophysiology of classic galactosemia with a severely reduced follicle pool at an early age requires an adjusted approach. In this article recommendations for physicians based on current knowledge concerning galactosemia and fertility preservation are made. Fertility preservation is only likely to be successful in very young prepubertal patients. In this group, cryopreservation of ovarian tissue is currently the only available technique. However, this technique is not ready for clinical application, it is considered experimental and reduces the ovarian reserve. Fertility preservation at an early age also raises ethical questions that should be taken into account. In addition, spontaneous conception despite POI is well described in classic galactosemia. The uncertainty surrounding fertility preservation and the significant chance of spontaneous pregnancy warrant counseling towards conservative application of these techniques. We propose that fertility preservation should only be offered with appropriate institutional research ethics approval to classic galactosemia girls at a young prepubertal age.
Classical Hamiltonian structures in wave packet dynamics
NASA Astrophysics Data System (ADS)
Gray, Stephen K.; Verosky, John M.
1994-04-01
The general, N state matrix representation of the time-dependent Schrödinger equation is equivalent to an N degree of freedom classical Hamiltonian system. We describe how classical mechanical methods and ideas can be applied towards understanding and modeling exact quantum dynamics. Two applications are presented. First, we illustrate how qualitative insights may be gained by treating the two state problem with a time-dependent coupling. In the case of periodic coupling, Poincaré surfaces of section are used to view the quantum dynamics, and features such as the Floquet modes take on interesting interpretations. The second application illustrates computational implications by showing how Liouville's theorem, or more generally the symplectic nature of classical Hamiltonian dynamics, provides a new perspective for carrying out numerical wave packet propagation. We show how certain simple and explicit symplectic integrators can be used to numerically propagate wave packets. The approach is illustrated with an application to the problem of a diatomic molecule interacting with a laser, although it and related approaches may be useful for describing a variety of problems.
Classical and quantum-mechanical state reconstruction
NASA Astrophysics Data System (ADS)
Khanna, F. C.; Mello, P. A.; Revzen, M.
2012-07-01
The aim of this paper is to present the subject of state reconstruction in classical and in quantum physics, a subject that deals with the experimentally acquired information that allows the determination of the physical state of a system. Our first purpose is to explain a method for retrieving a classical state in phase space, similar to that used in medical imaging known as computer-aided tomography. It is remarkable that this method can be taken over to quantum mechanics, where it leads to a description of the quantum state in terms of the Wigner function which, although it may take on negative values, plays the role of the probability density in phase space in classical physics. We then present another approach to quantum state reconstruction based on the notion of mutually unbiased bases—a notion of current research interest, for which we give explanatory remarks—and indicate the relation between these two approaches. Since the subject of state reconstruction is rarely considered at the level of textbooks, the presentation in this paper is aimed at graduate-level readers.
Quantum reduplication of classical solitons
NASA Astrophysics Data System (ADS)
Sveshnikov, Konstantin
1993-09-01
The possible existence of a series of quantum copies of classical soliton solutions is discussed, which do not exist when the effective Planck constant of the theory γ tends to zero. Within the conventional weak-coupling expansion in √ γ such non-classical solitons are O(√ γ) in energy and therefore lie in between the true classical solutions and elementary quantum excitations. Analytic results concerning the shape functions, masses and characteristic scales of such quantum excitations are given for soliton models of a self-interacting scalar field. Stability properties and quantization of fluctuations in the neighborhood of these configurations are also discussed in detail.
Classical and quantum Malus laws
NASA Astrophysics Data System (ADS)
Wódkiewicz, Krzysztof
1995-04-01
The classical and the quantum Malus laws for light and spin are discussed. It is shown that for spin 1/2, the quantum Malus law is equivalent in form to the classical Malus law provided the statistical average involves a quasidistribution function that can become negative. A generalization of Malus's law for arbitrary spin s is obtained in the form of a Feynman path-integral representation for the Malus amplitude. The classical limit of the Malus amplitude for s-->∞ is discussed.
Quantum localization of classical mechanics
NASA Astrophysics Data System (ADS)
Batalin, Igor A.; Lavrov, Peter M.
2016-07-01
Quantum localization of classical mechanics within the BRST-BFV and BV (or field-antifield) quantization methods are studied. It is shown that a special choice of gauge fixing functions (or BRST-BFV charge) together with the unitary limit leads to Hamiltonian localization in the path integral of the BRST-BFV formalism. In turn, we find that a special choice of gauge fixing functions being proportional to extremals of an initial non-degenerate classical action together with a very special solution of the classical master equation result in Lagrangian localization in the partition function of the BV formalism.
Experimental contextuality in classical light
Li, Tao; Zeng, Qiang; Song, Xinbing; Zhang, Xiangdong
2017-01-01
The Klyachko, Can, Binicioglu, and Shumovsky (KCBS) inequality is an important contextuality inequality in three-level system, which has been demonstrated experimentally by using quantum states. Using the path and polarization degrees of freedom of classical optics fields, we have constructed the classical trit (cetrit), tested the KCBS inequality and its geometrical form (Wright’s inequality) in this work. The projection measurement has been implemented, the clear violations of the KCBS inequality and its geometrical form have been observed. This means that the contextuality inequality, which is commonly used in test of the conflict between quantum theory and noncontextual realism, may be used as a quantitative tool in classical optical coherence to describe correlation characteristics of the classical fields. PMID:28291227
Classical Foundations: Leah Rochel Johnson
ERIC Educational Resources Information Center
Lum, Lydia
2005-01-01
This article discusses the accomplishments of Leah Rochel Johnson, Assistant Professor of Classics and Ancient Mediterranean Studies and History, Pennsylvania State University. It provides insight into her values and beliefs and testimony from those who work most closely with her.
Experimental contextuality in classical light
NASA Astrophysics Data System (ADS)
Li, Tao; Zeng, Qiang; Song, Xinbing; Zhang, Xiangdong
2017-03-01
The Klyachko, Can, Binicioglu, and Shumovsky (KCBS) inequality is an important contextuality inequality in three-level system, which has been demonstrated experimentally by using quantum states. Using the path and polarization degrees of freedom of classical optics fields, we have constructed the classical trit (cetrit), tested the KCBS inequality and its geometrical form (Wright’s inequality) in this work. The projection measurement has been implemented, the clear violations of the KCBS inequality and its geometrical form have been observed. This means that the contextuality inequality, which is commonly used in test of the conflict between quantum theory and noncontextual realism, may be used as a quantitative tool in classical optical coherence to describe correlation characteristics of the classical fields.
Quantum money with classical verification
Gavinsky, Dmitry
2014-12-04
We propose and construct a quantum money scheme that allows verification through classical communication with a bank. This is the first demonstration that a secure quantum money scheme exists that does not require quantum communication for coin verification. Our scheme is secure against adaptive adversaries - this property is not directly related to the possibility of classical verification, nevertheless none of the earlier quantum money constructions is known to possess it.
New Perspective on Classical Electromagnetism
2013-04-01
R. Feynman , R. Leighton, and M. Sands, The Feynman Lectures in Physics vol II (Addison-Wesley, Reading, MA, 1964). 6. W.K.H. Panofsky and M...of the basics of classical electromagnetism is provided by recognizing a previously overlooked law of induction as well as the physical reality of the...classical electromagnetism is provided by recognizing a previously overlooked law of induction as well as the physical reality of the vector potential
Classical theory of radiating strings
NASA Technical Reports Server (NTRS)
Copeland, Edmund J.; Haws, D.; Hindmarsh, M.
1990-01-01
The divergent part of the self force of a radiating string coupled to gravity, an antisymmetric tensor and a dilaton in four dimensions are calculated to first order in classical perturbation theory. While this divergence can be absorbed into a renormalization of the string tension, demanding that both it and the divergence in the energy momentum tensor vanish forces the string to have the couplings of compactified N = 1 D = 10 supergravity. In effect, supersymmetry cures the classical infinities.
Quantum money with classical verification
NASA Astrophysics Data System (ADS)
Gavinsky, Dmitry
2014-12-01
We propose and construct a quantum money scheme that allows verification through classical communication with a bank. This is the first demonstration that a secure quantum money scheme exists that does not require quantum communication for coin verification. Our scheme is secure against adaptive adversaries - this property is not directly related to the possibility of classical verification, nevertheless none of the earlier quantum money constructions is known to possess it.
Planck's radiation law: is a quantum-classical perspective possible?
NASA Astrophysics Data System (ADS)
Marrocco, Michele
2016-05-01
Planck's radiation law provides the solution to the blackbody problem that marks the decline of classical physics and the rise of the quantum theory of the radiation field. Here, we venture to suggest the possibility that classical physics might be equally suitable to deal with the blackbody problem. A classical version of the Planck's radiation law seems to be achievable if we learn from the quantum-classical correspondence between classical Mie theory and quantum-mechanical wave scattering from spherical scatterers (partial wave analysis). This correspondence designs a procedure for countable energy levels of the radiation trapped within the blackbody treated within the multipole approach of classical electrodynamics (in place of the customary and problematic expansion in terms of plane waves that give rise to the ultraviolet catastrophe). In turn, introducing the Boltzmann discretization of energy levels, the tools of classical thermodynamics and statistical theory become available for the task. On the other hand, the final result depends on a free parameter whose physical units are those of an action. Tuning this parameter on the value given by the Planck constant makes the classical result agree with the canonical Planck's radiation law.
Universal local symmetries and nonsuperposition in classical mechanics.
Gozzi, Ennio; Pagani, Carlo
2010-10-08
In the Hilbert space formulation of classical mechanics, pioneered by Koopman and von Neumann, there are potentially more observables than in the standard approach to classical mechanics. In this Letter, we show that actually many of those extra observables are not invariant under a set of universal local symmetries which appear once the Koopman and von Neumann formulation is extended to include the evolution of differential forms. Because of their noninvariance, those extra observables have to be removed. This removal makes the superposition of states in the Koopman and von Neumann formulation, and as a consequence also in classical mechanics, impossible.
NASA Astrophysics Data System (ADS)
Lacquaniti, Francesco; Ivanenko, Yuri P.; Zago, Myrka
2016-07-01
Starting from the classical concepts introduced by Sherrington [1] and considerably elaborated by Bernstein [2], much has been learned about motor synergies in the last several years. The contributions of the group funded by the European project ;The Hand Embodied; are remarkable in the field of biological and robotic control of the hand based on synergies, and they are reflected in this enjoyable review [3]. There, Santello et al. adopt Bernstein's definition of motor synergies as multiple elements working together towards a common goal, with the result that multiple degrees of freedom are controlled within a lower-dimensional space than the available number of dimensions.
NASA Astrophysics Data System (ADS)
Khrennikov, Andrei
2011-03-01
The idea that quantum randomness can be reduced to randomness of classical fields (fluctuating at time and space scales which are essentially finer than scales approachable in modern quantum experiments) is rather old. Various models have been proposed, e.g., stochastic electrodynamics or the semiclassical model. Recently a new model, so called prequantum classical statistical field theory (PCSFT), was developed. By this model a "quantum system" is just a label for (so to say "prequantum") classical random field. Quantum averages can be represented as classical field averages. Correlations between observables on subsystems of a composite system can be as well represented as classical correlations. In particular, it can be done for entangled systems. Creation of such classical field representation demystifies quantum entanglement. In this paper we show that quantum dynamics (given by Schrödinger's equation) of entangled systems can be represented as the stochastic dynamics of classical random fields. The "effect of entanglement" is produced by classical correlations which were present at the initial moment of time, cf. views of Albert Einstein.
Fundamental frequency from classical molecular dynamics.
Yamada, Tomonori; Aida, Misako
2015-02-07
We give a theoretical validation for calculating fundamental frequencies of a molecule from classical molecular dynamics (MD) when its anharmonicity is small enough to be treated by perturbation theory. We specifically give concrete answers to the following questions: (1) What is the appropriate initial condition of classical MD to calculate the fundamental frequency? (2) From that condition, how accurately can we extract fundamental frequencies of a molecule? (3) What is the benefit of using ab initio MD for frequency calculations? Our analytical approaches to those questions are classical and quantum normal form theories. As numerical examples we perform two types of MD to calculate fundamental frequencies of H2O with MP2/aug-cc-pVTZ: one is based on the quartic force field and the other one is direct ab initio MD, where the potential energies and the gradients are calculated on the fly. From those calculations, we show comparisons of the frequencies from MD with the post vibrational self-consistent field calculations, second- and fourth-order perturbation theories, and experiments. We also apply direct ab initio MD to frequency calculations of C-H vibrational modes of tetracene and naphthalene. We conclude that MD can give the same accuracy in fundamental frequency calculation as second-order perturbation theory but the computational cost is lower for large molecules.
Soliton splitting in quenched classical integrable systems
NASA Astrophysics Data System (ADS)
Gamayun, O.; Semenyakin, M.
2016-08-01
We take a soliton solution of a classical non-linear integrable equation and quench (suddenly change) its non-linearity parameter. For that we multiply the amplitude or the width of a soliton by a numerical factor η and take the obtained profile as a new initial condition. We find the values of η for which the post-quench solution consists of only a finite number of solitons. The parameters of these solitons are found explicitly. Our approach is based on solving the direct scattering problem analytically. We demonstrate how it works for Korteweg-de Vries, sine-Gordon and non-linear Schrödinger integrable equations.
Classical problems in computational aero-acoustics
NASA Technical Reports Server (NTRS)
Hardin, Jay C.
1996-01-01
In relation to the expected problems in the development of computational aeroacoustics (CAA), the preliminary applications were to classical problems where the known analytical solutions could be used to validate the numerical results. Such comparisons were used to overcome the numerical problems inherent in these calculations. Comparisons were made between the various numerical approaches to the problems such as direct simulations, acoustic analogies and acoustic/viscous splitting techniques. The aim was to demonstrate the applicability of CAA as a tool in the same class as computational fluid dynamics. The scattering problems that occur are considered and simple sources are discussed.
Liu, Shu-Zheng; Zhang, Fang; Quan, Pei-Liang; Lu, Jian-Bang; Liu, Zhi-Cai; Sun, Xi-Bin
2012-01-01
In recent decades, decreasing trends in esophageal cancer mortality have been observed across China. We here describe esophageal cancer mortality trends in Linzhou city, a high-incidence region of esophageal cancer in China, during 1988-2010 and make a esophageal cancer mortality projection in the period 2011-2020 using a Bayesian approach. Age standardized mortality rates were estimated by direct standardization to the World population structure in 1985. A Bayesian age-period-cohort (BAPC) analysis was carried out in order to investigate the effect of the age, period and birth cohort on esophageal cancer mortality in Linzhou during 1988-2010 and to estimate future trends for the period 2011-2020. Age-adjusted rates for men and women decreased from 1988 to 2005 and changed little thereafter. Risk increased from 30 years of age until the very elderly. Period effects showed little variation in risk throughout 1988-2010. In contrast, a cohort effect showed risk decreased greatly in later cohorts. Forecasting, based on BAPC modeling, resulted in a increasing burden of mortality and a decreasing age standardized mortality rate of esophageal cancer in Linzhou city. The decrease of esophageal cancer mortality risk since the 1930 cohort could be attributable to the improvements of social- economic environment and lifestyle. The standardized mortality rates of esophageal cancer should decrease continually. The effect of aging on the population could explain the increase in esophageal mortality projected for 2020.
Quantum remnants in the classical limit
NASA Astrophysics Data System (ADS)
Kowalski, A. M.; Plastino, A.
2016-09-01
We analyze here the common features of two dynamical regimes: a quantum and a classical one. We deal with a well known semi-classic system in its route towards the classical limit, together with its purely classic counterpart. We wish to ascertain i) whether some quantum remnants can be found in the classical limit and ii) the details of the quantum-classic transition. The so-called mutual information is the appropriate quantifier for this task. Additionally, we study the Bandt-Pompe's symbolic patterns that characterize dynamical time series (representative of the semi-classical system under scrutiny) in their evolution towards the classical limit.
Classical anomalies for spinning particles
NASA Astrophysics Data System (ADS)
Gamboa, Jorge; Plyushchay, Mikhail
1998-02-01
We discuss the phenomenon of classical anomaly. It is observed for 3D Berezin-Marinov (BM), Barducci-Casalbuoni-Lusanna (BCL) and Cortés-Plyushchay-Velázquez (CPV) pseudoclassical spin particle models. We show that quantum mechanically these different models correspond to the same P, T-invariant system of planar fermions, but the quantum system has global symmetries being not reproducible classically in full in any of the models. We demonstrate that the specific U(1) gauge symmetry characterized by the opposite coupling constants of spin s = + {1}/{2} and s = - {1}/{2} states has a natural classical analog in the CPV model but can be reproduced in the BM and BCL models in an obscure and rather artificial form. We also show that the BM and BCL models quantum mechanically are equivalent in any odd-dimensional space-time, but describe different quantum systems in even space-time dimensions.
From classical to quantum criticality
NASA Astrophysics Data System (ADS)
Podolsky, Daniel; Shimshoni, Efrat; Silvi, Pietro; Montangero, Simone; Calarco, Tommaso; Morigi, Giovanna; Fishman, Shmuel
2014-06-01
We study the crossover from classical to quantum phase transitions at zero temperature within the framework of ϕ4 theory. The classical transition at zero temperature can be described by the Landau theory, turning into a quantum Ising transition with the addition of quantum fluctuations. We perform a calculation of the transition line in the regime where the quantum fluctuations are weak. The calculation is based on a renormalization group analysis of the crossover between classical and quantum transitions, and is well controlled even for space-time dimensionality D below 4. In particular, for D =2 we obtain an analytic expression for the transition line which is valid for a wide range of parameters, as confirmed by numerical calculations based on the density matrix renormalization group. This behavior could be tested by measuring the phase diagram of the linear-zigzag instability in systems of trapped ions or repulsively interacting dipoles.
Entropy concepts in classical electrodynamics
NASA Astrophysics Data System (ADS)
Cole, Daniel C.
2002-11-01
Aspects of entropy and related thermodynamic analyses are discussed here that have been deduced in recent years in the area of classical electrodynamics. A motivating factor for most of this work has been an attempted theory of nature often called, "stochastic electrodynamics" (SED). This theory involves classical electrodynamics (Maxwell's equations plus the relativistic version of Newton's second law of motion for particles), but with the consideration that motion and fluctuations should not necessarily be assumed to reduce to zero at temperature T = 0. Both fairly subtle and rather blatant assumptions were often imposed in early thermodynamic analyses of electrodynamic systems that prevented the analyses from being sufficiently general to account for these "zero-point" properties, which hindered classical physics from being able to better account for quantum mechanical phenomena observed in nature. In turn, such thermodynamic considerations have helped motivate many of the key ideas of SED.
Optimum Onager: The Classical Mechanics of a Classical Siege Engine
ERIC Educational Resources Information Center
Denny, Mark
2009-01-01
The onager is a throwing weapon of classical antiquity, familiar to both the ancient Greeks and Romans. Here we analyze the dynamics of onager operation and derive the optimum angle for launching a projectile to its maximum range. There is plenty of scope for further considerations about increasing onager range, and so by thinking about how this…
Overview of Classical Swine Fever (Hog Cholera, Classical Swine fever)
Technology Transfer Automated Retrieval System (TEKTRAN)
Classical swine fever is a contagious often fatal disease of pigs clinically characterized by high body temperature, lethargy, yellowish diarrhea, vomits and purple skin discoloration of ears, lower abdomen and legs. It was first described in the early 19th century in the USA. Later, a condition i...
Quantum teleportation without classical channel
NASA Astrophysics Data System (ADS)
Al Amri, M.; Li, Zheng-Hong; Zubairy, M. Suhail
2016-11-01
For the first time, we show how quantum teleportation can be achieved without the assistance of classical channels. Our protocol does not need any pre-established entangled photon pairs beforehand. Just by utilizing quantum Zeno effect and couterfactual communication idea, we can achieve two goals; entangling a photon and an atom and also disentangling them by non-local interaction. Information is completely transferred from atom to photon with controllable disentanglement processes. More importantly, there is no need to confirm teleportation results via classical channels.
NASA Astrophysics Data System (ADS)
Kirkpatrick, K. A.
2003-05-01
A simple classical probabilistic system (a simple card game) classically exemplifies Aharonov and Vaidman's 'three-box 'paradox'' (1991 J. Phys. A: Math. Gen. 24 2315), implying that the three-box example is neither quantal nor a paradox and leaving one with less difficulty to busy the interpreters of quantum mechanics. An ambiguity in the usual expression of the retrodiction formula is shown to have misled Albert et al (1985 Phys. Rev. Lett. 54 5) to a result not, in fact, 'curious'; the discussion illustrates how to avoid this ambiguity.
Comparing classical and quantum equilibration
NASA Astrophysics Data System (ADS)
Malabarba, Artur S. L.; Farrelly, Terry; Short, Anthony J.
2016-09-01
By using a physically relevant and theory independent definition of measurement-based equilibration, we show quantitatively that equilibration is easier for quantum systems than for classical systems, in the situation where the initial state of the system is completely known (a pure state). This shows that quantum equilibration is a fundamental aspect of many quantum systems, while classical equilibration relies on experimental ignorance. When the state is not completely known (a mixed state), this framework also shows that quantum equilibration requires weaker conditions.
Sławuta, P; Glińska-Suchocka, K
2012-01-01
Classically, the acid-base balance (ABB) is described by the Henderson-Hasselbach equation, where the blood pH is a result of a metabolic components--the HCO3(-) concentration and a respiratory component--pCO2. The Stewart model assumes that the proper understanding of the organisms ABB is based on an analysis of: pCO2, Strong Ion difference (SID)--the difference strong cation and anion concentrations in the blood serum, and the Acid total (Atot)--the total concentration of nonvolatile weak acids. Right sided heart failure in dogs causes serious haemodynamic disorders in the form of peripheral stasis leading to formation of transudates in body cavities, which in turn causes ABB respiratory and metabolic disorders. The study was aimed at analysing the ABB parameters with the use of the classic method and the Stewart model in dogs with the right sided heart failure and a comparison of both methods for the purpose of their diagnostic and therapeutic utility. The study was conducted on 10 dogs with diagnosed right sided heart failure. Arterial and venous blood was drawn from the animals. Analysis of pH, pCO2 and HCO3(-) was performed from samples of arterial blood. Concentrations of Na+, K+, Cl(-), P(inorganic), albumins and lactate were determined from venous blood samples and values of Strong Ion difference of Na+, K+ and Cl(-) (SID3), Strong Ion difference of Na+, K+, Cl(-) and lactate (SID4), Atot, Strong Ion difference effective (SIDe) and Strong Ion Gap (SIG4) were calculated. The conclusions are as follows: 1) diagnosis of ABB disorders on the basis of the Stewart model showed metabolic alkalosis in all dogs examined, 2) in cases of circulatory system diseases, methodology based on the Stewart model should be applied for ABB disorder diagnosis, 3) if a diagnosis of ABB disorders is necessary, determination of pH, pCO2 and HCO3(-) as well as concentrations of albumins and P(inorganic) should be determined on a routine basis, 4) for ABB disorder diagnosis, the
2010-01-01
Background Patients-Reported Outcomes (PRO) are increasingly used in clinical and epidemiological research. Two main types of analytical strategies can be found for these data: classical test theory (CTT) based on the observed scores and models coming from Item Response Theory (IRT). However, whether IRT or CTT would be the most appropriate method to analyse PRO data remains unknown. The statistical properties of CTT and IRT, regarding power and corresponding effect sizes, were compared. Methods Two-group cross-sectional studies were simulated for the comparison of PRO data using IRT or CTT-based analysis. For IRT, different scenarios were investigated according to whether items or person parameters were assumed to be known, to a certain extent for item parameters, from good to poor precision, or unknown and therefore had to be estimated. The powers obtained with IRT or CTT were compared and parameters having the strongest impact on them were identified. Results When person parameters were assumed to be unknown and items parameters to be either known or not, the power achieved using IRT or CTT were similar and always lower than the expected power using the well-known sample size formula for normally distributed endpoints. The number of items had a substantial impact on power for both methods. Conclusion Without any missing data, IRT and CTT seem to provide comparable power. The classical sample size formula for CTT seems to be adequate under some conditions but is not appropriate for IRT. In IRT, it seems important to take account of the number of items to obtain an accurate formula. PMID:20338031
Classical Music as Enforced Utopia
ERIC Educational Resources Information Center
Leech-Wilkinson, Daniel
2016-01-01
In classical music composition, whatever thematic or harmonic conflicts may be engineered along the way, everything always turns out for the best. Similar utopian thinking underlies performance: performers see their job as faithfully carrying out their master's (the composer's) wishes. The more perfectly they represent them, the happier the…
Classical and molecular genetic mapping
Technology Transfer Automated Retrieval System (TEKTRAN)
A brief history of classical genetic mapping in soybean [Glycine max (L.) Merr.] is described. Detailed descriptions are given of the development of molecular genetic linkage maps based upon various types of DNA markers Like many plant and animal species, the first molecular map of soybean was bas...
Classics in Reading: A Survey.
ERIC Educational Resources Information Center
Froese, Victor
1982-01-01
Frank Smith and Kenneth Goodman were the most frequently cited authors; Bond and Dykstra's "The Cooperative Research Program in First Grade Reading Instruction" and Chall's "Learning to Read: The Great Debate" the most frequently cited works in a survey that asked graduate faculty in reading to name "classics" in reading research. (FL)
Teaching Classical Mechanics Using Smartphones
ERIC Educational Resources Information Center
Chevrier, Joel; Madani, Laya; Ledenmat, Simon; Bsiesy, Ahmad
2013-01-01
A number of articles published in this column have dealt with topics in classical mechanics. This note describes some additional examples employing a smartphone and the new software iMecaProf. Steve Jobs presented the iPhone as "perfect for gaming." Thanks to its microsensors connected in real time to the numerical world, physics…
Classical simulation of entangled states
NASA Astrophysics Data System (ADS)
Bharath, H. M.; Ravishankar, V.
2014-06-01
Characterization of nonclassicality or quantumness of a state is fundamental to foundations of quantum mechanics and quantum information. At the heart of the problem is the question whether there exist classical systems—howsoever complicated—that can mimic a given quantum state. Whilst this has been traditionally addressed through the violation of Bell inequality or nonseparability, we show that it is possible to go beyond them, by introducing the concept of classical simulation. Focusing on the two-qubit case, we show that, while for pure states, classical simulability is equivalent to existence of a local hidden variable (LHV) model, the conditions for simulability can be weaker for mixed states, demanding what we call only a generalized LHV description. Consequently, quantum states which defy a classical simulation—which we call exceptional—may require conditions which are more stringent than violation of Bell inequalities. We illustrate these features with a number of representative examples and discuss the underlying reasons, by employing fairly simple arguments.
Relative Clauses in Classical Nahuatl
ERIC Educational Resources Information Center
Langacker, Ronald W.
1975-01-01
Jane Rosenthal's paper on relative clauses in Classical Nahuatl is discussed, and it is argued that she misses an important generalization. An alternative analysis to a class of relative pronouns and new rules for the distribution of relative pronouns are proposed. (SC)
Vowel intelligibility in classical singing.
Gregg, Jean Westerman; Scherer, Ronald C
2006-06-01
Vowel intelligibility during singing is an important aspect of communication during performance. The intelligibility of isolated vowels sung by Western classically trained singers has been found to be relatively low, in fact, decreasing as pitch rises, and it is lower for women than for men. The lack of contextual cues significantly deteriorates vowel intelligibility. It was postulated in this study that the reduced intelligibility of isolated sung vowels may be partly from the vowels used by the singers in their daily vocalises. More specifically, if classically trained singers sang only a few American English vowels during their vocalises, their intelligibility for American English vowels would be less than for those classically trained singers who usually vocalize on most American English vowels. In this study, there were 21 subjects (15 women, 6 men), all Western classically trained performers as well as teachers of classical singing. They sang 11 words containing 11 different American English vowels, singing on two pitches a musical fifth apart. Subjects were divided into two groups, those who normally vocalize on 4, 5, or 6 vowels, and those who sing all 11 vowels during their daily vocalises. The sung words were cropped to isolate the vowels, and listening tapes were created. Two listening groups, four singing teachers and five speech-language pathologists, were asked to identify the vowels intended by the singers. Results suggest that singing fewer vowels during daily vocalises does not decrease intelligibility compared with singing the 11 American English vowels. Also, in general, vowel intelligibility was lower with the higher pitch, and vowels sung by the women were less intelligible than those sung by the men. Identification accuracy was about the same for the singing teacher listeners and the speech-language pathologist listeners except for the lower pitch, where the singing teachers were more accurate.
No return to classical reality
NASA Astrophysics Data System (ADS)
Jennings, David; Leifer, Matthew
2016-01-01
At a fundamental level, the classical picture of the world is dead, and has been dead now for almost a century. Pinning down exactly which quantum phenomena are responsible for this has proved to be a tricky and controversial question, but a lot of progress has been made in the past few decades. We now have a range of precise statements showing that whatever the ultimate laws of nature are, they cannot be classical. In this article, we review results on the fundamental phenomena of quantum theory that cannot be understood in classical terms. We proceed by first granting quite a broad notion of classicality, describe a range of quantum phenomena (such as randomness, discreteness, the indistinguishability of states, measurement-uncertainty, measurement-disturbance, complementarity, non-commutativity, interference, the no-cloning theorem and the collapse of the wave-packet) that do fall under its liberal scope, and then finally describe some aspects of quantum physics that can never admit a classical understanding - the intrinsically quantum mechanical aspects of nature. The most famous of these is Bell's theorem, but we also review two more recent results in this area. Firstly, Hardy's theorem shows that even a finite-dimensional quantum system must contain an infinite amount of information, and secondly, the Pusey-Barrett-Rudolph theorem shows that the wave function must be an objective property of an individual quantum system. Besides being of foundational interest, results of this sort now find surprising practical applications in areas such as quantum information science and the simulation of quantum systems.
Strong Analog Classical Simulation of Coherent Quantum Dynamics
NASA Astrophysics Data System (ADS)
Wang, Dong-Sheng
2017-02-01
A strong analog classical simulation of general quantum evolution is proposed, which serves as a novel scheme in quantum computation and simulation. The scheme employs the approach of geometric quantum mechanics and quantum informational technique of quantum tomography, which applies broadly to cases of mixed states, nonunitary evolution, and infinite dimensional systems. The simulation provides an intriguing classical picture to probe quantum phenomena, namely, a coherent quantum dynamics can be viewed as a globally constrained classical Hamiltonian dynamics of a collection of coupled particles or strings. Efficiency analysis reveals a fundamental difference between the locality in real space and locality in Hilbert space, the latter enables efficient strong analog classical simulations. Examples are also studied to highlight the differences and gaps among various simulation methods. Funding support from NSERC of Canada and a research fellowship at Department of Physics and Astronomy, University of British Columbia are acknowledged
Miller, William H.; Orel, Ann E.
1981-06-01
A classical interpretation of the Dirac–Van Vleck spin version of valence bond theory is used in this research to obtain a classical model for electronic degrees of freedom within the valence bond framework. The approach is illustrated by deriving the explicit forms of the classical Hamiltonians, involving electronic and heavy particle degrees of freedom, for the H–H_{2}, F–H_{2}, and O–H_{2} systems. It is also shown how the initial conditions for both electronic and heavy particle degrees of freedom are chosen to carry out a classical trajectory simulation of collision processes. In addition, the attractive feature of this model is that it is as easily applicable to electronically nonadiabatic processes as it is to adiabatic ones.
Classical Analog to Entanglement Reversibility
NASA Astrophysics Data System (ADS)
Chitambar, Eric; Fortescue, Ben; Hsieh, Min-Hsiu
2015-08-01
In this Letter we study the problem of secrecy reversibility. This asks when two honest parties can distill secret bits from some tripartite distribution pX Y Z and transform secret bits back into pX Y Z at equal rates using local operation and public communication. This is the classical analog to the well-studied problem of reversibly concentrating and diluting entanglement in a quantum state. We identify the structure of distributions possessing reversible secrecy when one of the honest parties holds a binary distribution, and it is possible that all reversible distributions have this form. These distributions are more general than what is obtained by simply constructing a classical analog to the family of quantum states known to have reversible entanglement. An indispensable tool used in our analysis is a conditional form of the Gács-Körner common information.
Invariants from classical field theory
Diaz, Rafael; Leal, Lorenzo
2008-06-15
We introduce a method that generates invariant functions from perturbative classical field theories depending on external parameters. By applying our methods to several field theories such as Abelian BF, Chern-Simons, and two-dimensional Yang-Mills theory, we obtain, respectively, the linking number for embedded submanifolds in compact varieties, the Gauss' and the second Milnor's invariant for links in S{sup 3}, and invariants under area-preserving diffeomorphisms for configurations of immersed planar curves.
Psoriasis: classical and emerging comorbidities*
de Oliveira, Maria de Fátima Santos Paim; Rocha, Bruno de Oliveira; Duarte, Gleison Vieira
2015-01-01
Psoriasis is a chronic inflammatory systemic disease. Evidence shows an association of psoriasis with arthritis, depression, inflammatory bowel disease and cardiovascular diseases. Recently, several other comorbid conditions have been proposed as related to the chronic inflammatory status of psoriasis. The understanding of these conditions and their treatments will certainly lead to better management of the disease. The present article aims to synthesize the knowledge in the literature about the classical and emerging comorbidities related to psoriasis. PMID:25672294
Quantum to classical randomness extractors
NASA Astrophysics Data System (ADS)
Wehner, Stephanie; Berta, Mario; Fawzi, Omar
2013-03-01
The goal of randomness extraction is to distill (almost) perfect randomness from a weak source of randomness. When the source yields a classical string X, many extractor constructions are known. Yet, when considering a physical randomness source, X is itself ultimately the result of a measurement on an underlying quantum system. When characterizing the power of a source to supply randomness it is hence a natural question to ask, how much classical randomness we can extract from a quantum system. To tackle this question we here introduce the notion of quantum-to-classical randomness extractors (QC-extractors). We identify an entropic quantity that determines exactly how much randomness can be obtained. Furthermore, we provide constructions of QC-extractors based on measurements in a full set of mutually unbiased bases (MUBs), and certain single qubit measurements. As the first application, we show that any QC-extractor gives rise to entropic uncertainty relations with respect to quantum side information. Such relations were previously only known for two measurements. As the second application, we resolve the central open question in the noisy-storage model [Wehner et al., PRL 100, 220502 (2008)] by linking security to the quantum capacity of the adversary's storage device.
Optimum Onager: The Classical Mechanics of a Classical Siege Engine
NASA Astrophysics Data System (ADS)
Denny, Mark
2009-12-01
The onager is a throwing weapon of classical antiquity, familiar to both the ancient Greeks and Romans. Here we analyze the dynamics of onager operation and derive the optimum angle for launching a projectile to its maximum range. There is plenty of scope for further considerations about increasing onager range, and so by thinking about how this machine might be improved, a student can gain insight beyond the equations of motion and can test hypotheses on readily available working models. Some of these performance improvements are considered in this paper.
Classical molecular dynamics simulation of electronically non-adiabatic processes.
Miller, William H; Cotton, Stephen J
2016-12-22
Both classical and quantum mechanics (as well as hybrids thereof, i.e., semiclassical approaches) find widespread use in simulating dynamical processes in molecular systems. For large chemical systems, however, which involve potential energy surfaces (PES) of general/arbitrary form, it is usually the case that only classical molecular dynamics (MD) approaches are feasible, and their use is thus ubiquitous nowadays, at least for chemical processes involving dynamics on a single PES (i.e., within a single Born-Oppenheimer electronic state). This paper reviews recent developments in an approach which extends standard classical MD methods to the treatment of electronically non-adiabatic processes, i.e., those that involve transitions between different electronic states. The approach treats nuclear and electronic degrees of freedom (DOF) equivalently (i.e., by classical mechanics, thereby retaining the simplicity of standard MD), and provides "quantization" of the electronic states through a symmetrical quasi-classical (SQC) windowing model. The approach is seen to be capable of treating extreme regimes of strong and weak coupling between the electronic states, as well as accurately describing coherence effects in the electronic DOF (including the de-coherence of such effects caused by coupling to the nuclear DOF). A survey of recent applications is presented to illustrate the performance of the approach. Also described is a newly developed variation on the original SQC model (found universally superior to the original) and a general extension of the SQC model to obtain the full electronic density matrix (at no additional cost/complexity).
The structure of the classical cosmological singularity
NASA Astrophysics Data System (ADS)
Tipler, Frank J.
The existence of an all-encompassing initial classical cosmological singularity is established: it is shown that if: (1) global hyperbolicity, (2) the timelike convergence condition, and (3) all past-directed nonspacelike geodesics start to reconverge within a compact region in the causal past of the present-day earth, then all timelike curves in the past have a finite proper time length less than a universal constant L. It is argued that an analogue of this predicted cosmological singularity should exist even when quantum effects are taken into account. In particular, in a closed Friedmann radiation-filled universe quantized via the ADM method, the R = 0 singularity still exists and influences wave packet evolution at all times. Furthermore, quantum effects can in most cases eliminate curvature singularities only by introducing singularities in the universal action; most classical closed universes have finite action if and only if they begin and end in curvature singularities. Finally, the two basic ways of studying the structure of cosmological singularities are reviewed: completion methods (e.g., the c-boundary construction), and approach methods (e.g., analyzing metric behavior in a synchronous coordinate system).
Classical versus Computer Algebra Methods in Elementary Geometry
ERIC Educational Resources Information Center
Pech, Pavel
2005-01-01
Computer algebra methods based on results of commutative algebra like Groebner bases of ideals and elimination of variables make it possible to solve complex, elementary and non elementary problems of geometry, which are difficult to solve using a classical approach. Computer algebra methods permit the proof of geometric theorems, automatic…
Classic Book Units for G/C/T Youngsters.
ERIC Educational Resources Information Center
Karges-Bone, Linda
1991-01-01
Use of classic book units with gifted elementary students is described as an interdisciplinary approach to stimulating student interest. Sample activities are offered from a unit on Mark Twain's "Huckleberry Finn," with linguistic, artistic-creative, scientific, mathematical, and socio-leadership activities, classified as application,…
E-Classical Fairy Tales: Multimedia Builder as a Tool
ERIC Educational Resources Information Center
Eteokleous, Nikleia; Ktoridou, Despo; Tsolakidis, Symeon
2011-01-01
The study examines pre-service teachers' experiences in delivering a traditional-classical fairy tale using the Multimedia Builder software, in other words an e-fairy tale. A case study approach was employed, collecting qualitative data through classroom observations and focus groups. The results focus on pre-service teachers' reactions, opinions,…
Poma, A B; Delle Site, L
2011-06-14
Adaptive resolution simulations for classical systems are currently made within a reasonably consistent theoretical framework. Recently we have extended this approach to the quantum-classical coupling by mapping the quantum nature of an atom onto a classical polymer ring representation within the path integral approach [Poma & Delle Site, Phys. Rev. Lett., 2010, 104, 250201]. In this way the process of interfacing adaptively a quantum representation to a classical one corresponds to the problem of interfacing two regions with a different number of effective "classical" degrees of freedom; thus the classical formulation of the adaptive algorithm applies straightforwardly to the quantum-classical problem. In this work we show the robustness of such an approach for a liquid of para-hydrogen at low temperature. This system represents a highly challenging conceptual and technical test for the adaptive approach due to the extreme thermodynamical conditions where quantum effects play a central role.
Classical Optics and its Applications
NASA Astrophysics Data System (ADS)
Mansuripur, Masud
2009-02-01
Preface; Introduction; 1. Abbe's sine condition; 2. Fourier optics; 3. Effect of polarization on diffraction in systems of high numerical aperture; 4. Gaussian beam optics; 5. Coherent and incoherent imaging; 6. First-order temporal coherence in classical optics; 7. The Van Cittert-Zernike theorem; 8. Partial polarization, Stokes parameters, and the Poincarè Sphere; 9. Second-order coherence and the Hanbury Brown - Twiss experiment; 10. What in the world are surface plasmons?; 11. Surface plasmon polaritons on metallic surfaces; 12. The Faraday effecy; 13. The magneto-optical Kerr effect; 14. The Sagnac interferometer; 15. Fabry-Perot etalons in polarized light; 16. The Ewald-Oseen extinction theorem; 17. Reciprocity in classical Linear optics; 18. Optical pulse compression; 19. The uncertainty principle in classical optics; 20. Omni-directional dielectric mirrors; 21. Optical vortices; 22. Geometric-optical rays, Poynting's vector, and field momenta; 23. Doppler shift, stellar aberration, and convection of light by moving Media; 24. Diffraction gratings; 25. Diffractive optical elements; 26. The talbot effect; 27. Some quirks of total internal reflection; 28. Evanescent coupling; 29. Internal and external conical refraction; 30. Transmission of light through small elliptical apertures; 31. The method of Fox and Li; 32. The beam propagation method; 33. Launching light into a Fiber; 34. The optics of demiconductor fiode Laser; 35. Michelson's dtellar interferometer; 36. Bracewell's interferometric telescope; 37. Scanning optical microscopy; 38. Zernike's method of phase contrast; 39. Polarization microscopy; 40. Nomarski's differential interference contrast microscope; 41. The Van Leeuwenhoek microscope; 42. Projection photolithography; 43. Interaction of light with subwavelength structures; 44 The Ronchi test; 45. The Shack-Hartmann Wavefront sensor; 46. Ellipsometry; 47. Holography and holographic interferometry; 48. Self-focusing in non-linear optical media; 49
Classical analog of quantum phase
Ord, G.N.
1992-07-01
A modified version of the Feynman relativistic chessboard model (FCM) is investigated in which the paths involved are spirals in the space-time. Portions of the paths in which the particle`s proper time is reversed are interpreted in terms of antiparticles. With this intepretation the particle-antiparticle field produced by such trajectories provides a classical analog of the phase associated with particle paths in the unmodified FCM. It is shwon that in the nonrelativistic limit the resulting kernel is the correct Dirac propagator and that particle-antiparticle symmetry is in this case responsible for quantum interference. 7 refs., 3 figs.
Superadditivity of classical capacity revisited
Pilyavets, Oleg V.; Karpov, Evgueni A.; Schäfer, Joachim
2014-12-04
We introduce new type of superadditivity for classical capacity of quantum channels, which involves the properties of channels’ environment. By imposing different restrictions on the total energy contained in channels’ environment we can consider different types of superadditivity. Using lossy bosonic and additive noise quantum channels as examples, we demonstrate that their capacities can be either additive or superadditive depending on the values of channels parameters. The parameters corresponding to transition between the additive and superadditive cases are related with recently found critical and supercritical parameters for Gaussian channels.
Classical dynamics on Snyder spacetime
NASA Astrophysics Data System (ADS)
Mignemi, S.
2015-04-01
We study the classical dynamics of a particle in Snyder spacetime, adopting the formalism of constrained Hamiltonian systems introduced by Dirac. We show that the motion of a particle in a scalar potential is deformed with respect to special relativity by terms of order βE2. A remarkable result is that in the relativistic Snyder model a consistent choice of the time variable must necessarily depend on the dynamics. This is a consequence of the nontrivial mixing between position and momentum coordinates intrinsic to the Snyder model.
Classics in Chemical Neuroscience: Haloperidol.
Tyler, Marshall W; Zaldivar-Diez, Josefa; Haggarty, Stephen J
2017-02-15
The discovery of haloperidol catalyzed a breakthrough in our understanding of the biochemical basis of schizophrenia, improved the treatment of psychosis, and facilitated deinstitutionalization. In doing so, it solidified the role for chemical neuroscience as a means to elucidate the molecular underpinnings of complex neuropsychiatric disorders. In this Review, we will cover aspects of haloperidol's synthesis, manufacturing, metabolism, pharmacology, approved and off-label indications, and adverse effects. We will also convey the fascinating history of this classic molecule and the influence that it has had on the evolution of neuropsychopharmacology and neuroscience.
Physiological characteristics of classical ballet.
Schantz, P G; Astrand, P O
1984-10-01
The aerobic and anaerobic energy yield during professional training sessions ("classes") of classical ballet as well as during rehearsed and performed ballets has been studied by means of oxygen uptake, heart rate, and blood lactate concentration determinations on professional ballet dancers from the Royal Swedish Ballet in Stockholm. The measured oxygen uptake during six different normal classes at the theatre averaged about 35-45% of the maximal oxygen uptake, and the blood lactate concentration averaged 3 mM (N = 6). During 10 different solo parts of choreographed dance (median length = 1.8 min) representative for moderately to very strenuous dance, an average oxygen uptake (measured during the last minute) of 80% of maximum and blood lactate concentration of 10 mM was measured (N = 10). In addition, heart rate registrations from soloists in different ballets during performance and final rehearsals frequently indicated a high oxygen uptake relative to maximum and an average blood lactate concentration of 11 mM (N = 5). Maximal oxygen uptake, determined in 1971 (N = 11) and 1983 (N = 13) in two different groups of dancers, amounted to on the average 51 and 56 ml X min-1 X kg-1 for the females and males, respectively. In conclusion, classical ballet is a predominantly intermittent type of exercise. In choreographed dance each exercise period usually lasts only a few minutes, but can be very demanding energetically, while during the dancers' basic training sessions, the energy yield is low.
Overuse injuries in classical ballet.
Khan, K; Brown, J; Way, S; Vass, N; Crichton, K; Alexander, R; Baxter, A; Butler, M; Wark, J
1995-05-01
Successful management of classical ballet dancers with overuse injuries requires an understanding of the art form, precise knowledge of anatomy and awareness of certain conditions. Turnout is the single most fundamental physical attribute in classical ballet and 'forcing turnout' frequently contributes to overuse injuries. Common presenting conditions arising from the foot and ankle include problems at the first metatarsophalangeal joint, second metatarsal stress fractures, flexor hallucis longus tendinitis and anterior and posterior ankle impingement syndromes. Persistent shin pain in dancers is often due to chronic compartment syndrome, stress fracture of the posteromedial or anterior tibia. Knee pain can arise from patellofemoral syndrome, patellar tendon insertional pathologies, or a combination of both. Hip and back problems are also prevalent in dancers. To speed injury recovery of dancers, it is important for the sports medicine team to cooperate fully. This permits the dancer to benefit from accurate diagnosis, technique correction where necessary, the full range of manual therapies to joint and soft tissue, appropriate strengthening programmes and maintenance of dance fitness during any time out of class with Pilates-based exercises and nutrition advice. Most overuse ballet conditions respond well to a combination of conservative therapies. Those dancers that do require surgical management still depend heavily on ballet-specific rehabilitation for a complete recovery.
Teaching classical mechanics using smartphones
NASA Astrophysics Data System (ADS)
Chevrier, Joel; Madani, Laya; Ledenmat, Simon; Bsiesy, Ahmad
2013-09-01
A number of articles published in this column have dealt with topics in classical mechanics. This note describes some additional examples employing a smartphone and the new software iMecaProf.4 Steve Jobs presented the iPhone as "perfect for gaming."5 Thanks to its microsensors connected in real time to the numerical world, physics teachers could add that smartphones are "perfect for teaching science." The software iMecaProf displays in real time the measured data on a screen. The visual representation is built upon the formalism of classical mechanics. iMecaProf receives data 100 times a second from iPhone sensors through a Wi-Fi connection using the application Sensor Data.6 Data are the three components of the acceleration vector in the smartphone frame and smartphone's orientation through three angles (yaw, pitch, and roll). For circular motion (uniform or not), iMecaProf uses independent measurements of the rotation angle θ, the angular speed dθ/dt, and the angular acceleration d2θ/dt2.
Friedreich Ataxia in Classical Galactosaemia.
Neville, Siobhán; O'Sullivan, Siobhan; Sweeney, Bronagh; Lynch, Bryan; Hanrahan, Donncha; Knerr, Ina; Lynch, Sally Ann; Crushell, Ellen
2016-01-01
Movement disorders such as ataxia are a recognized complication of classical galactosaemia, even in diet-compliant patients. Here, we report the coexistence of classical galactosaemia and Friedreich ataxia (FRDA) in nine children from seven Irish Traveller families. These two autosomal recessive disorders, the loci for which are located on either side of the centromere of chromosome 9, appear to be in linkage disequilibrium in this subgroup. Both conditions are known to occur with increased frequency amongst the Irish Traveller population.Each member of our cohort had been diagnosed with galactosaemia in the neonatal period, and all are homozygous for the common Q188R mutation in the GALT gene. Eight of the nine patients later presented with progressive ataxia, between the ages of 5-13 years. Another child presented in cardiac failure secondary to dilated cardiomyopathy at 7 years of age. He was not ataxic at presentation and, one year from diagnosis, his neurological examination remains normal. The diagnosis of FRDA was confirmed by detecting the common pathogenic GAA expansion in both alleles of the frataxin gene (FXN) in each patient.Neurological symptoms are easily attributed to an underlying diagnosis of galactosaemia. It is important to consider a diagnosis of Friedreich ataxia in a child from the Irish Traveller population with galactosaemia who presents with ataxia or cardiomyopathy.
Classically spinning and isospinning solitons
NASA Astrophysics Data System (ADS)
Battye, Richard A.; Haberichter, Mareike
2012-09-01
We investigate classically spinning topological solitons in (2+1)- and (3+1)-dimensional models; more explicitely spinning sigma model solitons in 2+1 dimensions and Skyrme solitons in 2+1 and 3+1 dimensions. For example, such types of solitons can be used to describe quasiparticle excitations in ferromagnetic quantum Hall systems or to model spin and isospin states of nuclei. The standard way to obtain solitons with quantised spin and isospin is the semiclassical quantization procedure: One parametrizes the zero-mode space - the space of energy-degenerate soliton configurations generated from a single soliton by spatial translations and rotations in space and isospace - by collective coordinates which are then taken to be time-dependent. This gives rise to additional dynamical terms in the Hamiltonian which can then be quantized following semiclassical quantization rules. A simplification which is often made in the literature is to apply a simple adiabatic approximation to the (iso)rotational zero modes of the soliton by assuming that the soliton's shape is rotational frequency independent. Our numerical results on classically spinning arbitrarily deforming soliton solutions clearly show that soliton deformation cannot be ignored.
Noisy quantum cellular automata for quantum versus classical excitation transfer.
Avalle, Michele; Serafini, Alessio
2014-05-02
We introduce a class of noisy quantum cellular automata on a qubit lattice that includes all classical Markov chains, as well as maps where quantum coherence between sites is allowed to build up over time. We apply such a construction to the problem of excitation transfer through 1D lattices, and compare the performance of classical and quantum dynamics with equal local transition probabilities. Our discrete approach has the merits of stripping down the complications of the open system dynamics, of clearly isolating coherent effects, and of allowing for an exact treatment of conditional dynamics, all while capturing a rich variety of dynamical behaviors.
Noisy Quantum Cellular Automata for Quantum versus Classical Excitation Transfer
NASA Astrophysics Data System (ADS)
Avalle, Michele; Serafini, Alessio
2014-05-01
We introduce a class of noisy quantum cellular automata on a qubit lattice that includes all classical Markov chains, as well as maps where quantum coherence between sites is allowed to build up over time. We apply such a construction to the problem of excitation transfer through 1D lattices, and compare the performance of classical and quantum dynamics with equal local transition probabilities. Our discrete approach has the merits of stripping down the complications of the open system dynamics, of clearly isolating coherent effects, and of allowing for an exact treatment of conditional dynamics, all while capturing a rich variety of dynamical behaviors.
High-NOON states by mixing quantum and classical light.
Afek, Itai; Ambar, Oron; Silberberg, Yaron
2010-05-14
Precision measurements can be brought to their ultimate limit by harnessing the principles of quantum mechanics. In optics, multiphoton entangled states, known as NOON states, can be used to obtain high-precision phase measurements, becoming more and more advantageous as the number of photons grows. We generated "high-NOON" states (N = 5) by multiphoton interference of quantum down-converted light with a classical coherent state in an approach that is inherently scalable. Super-resolving phase measurements with up to five entangled photons were produced with a visibility higher than that obtainable using classical light only.
Diminuendo: Classical Music and the Academy
ERIC Educational Resources Information Center
Asia, Daniel
2010-01-01
How is the tradition of Western classical music faring on university campuses? Before answering this question, it is necessary to understand what has transpired with classical music in the wider culture, as the relationship between the two is so strong. In this article, the author discusses how classical music has taken a big cultural hit in…
Africa in Classical Antiquity: A Curriculum Resource
ERIC Educational Resources Information Center
Masciantonio, Rudolph
1977-01-01
A curriculum resource developed by the School District of Philadelphia deals with Africa in Classical Antiquity. Each unit contains suggestions for lower, middle and upper schools. Topics covered are: history of Africa; great Africans in the Graeco-Roman world; racial attitudes; blacks in classical art, and Africa in classical literature. (CHK)
Africa in Classical Antiquity: A Curriculum Resource.
ERIC Educational Resources Information Center
Masciantonio, Rudolph; And Others
This curriculum resource is intended primarily to assist teachers of Latin and Greek to infuse material on Africa in classical antiquity into the curriculum at all levels. It gathers together background information on the role of Africa in classical antiquity that has not been treated in traditional classical language courses. The resource guide…
Introducing the Classics to Reluctant Readers.
ERIC Educational Resources Information Center
Lazarus, Lissa J.
Using the pocket classics can be a painless way to introduce the classics to eighth-grade students. Condensed versions of the classics can take the sting out of the reading, stimulate students' interest, and help prepare them for high school. To offer students in one eighth-grade class some control over their own learning, a contract system was…
Luis, Alfredo
2011-07-15
We study nonclassicality in the product of the probabilities of noncommuting observables. We show that within the quantum theory, nonclassical states can provide larger probability product than classical states, so that nonclassical states approach the nonfluctuating states of the classical theory more closely than classical states. This is particularized to relevant complementary observables such as conjugate quadratures, phase and number, quadrature and number, and orthogonal angular momentum components.
Generic emergence of classical features in quantum Darwinism
NASA Astrophysics Data System (ADS)
Brandão, Fernando G. S. L.; Piani, Marco; Horodecki, Paweł
2015-08-01
Quantum Darwinism posits that only specific information about a quantum system that is redundantly proliferated to many parts of its environment becomes accessible and objective, leading to the emergence of classical reality. However, it is not clear under what conditions this mechanism holds true. Here we prove that the emergence of classical features along the lines of quantum Darwinism is a general feature of any quantum dynamics: observers who acquire information indirectly through the environment have effective access at most to classical information about one and the same measurement of the quantum system. Our analysis does not rely on a strict conceptual splitting between a system-of-interest and its environment, and allows one to interpret any system as part of the environment of any other system. Finally, our approach leads to a full operational characterization of quantum discord in terms of local redistribution of correlations.
Generic emergence of classical features in quantum Darwinism.
Brandão, Fernando G S L; Piani, Marco; Horodecki, Paweł
2015-08-12
Quantum Darwinism posits that only specific information about a quantum system that is redundantly proliferated to many parts of its environment becomes accessible and objective, leading to the emergence of classical reality. However, it is not clear under what conditions this mechanism holds true. Here we prove that the emergence of classical features along the lines of quantum Darwinism is a general feature of any quantum dynamics: observers who acquire information indirectly through the environment have effective access at most to classical information about one and the same measurement of the quantum system. Our analysis does not rely on a strict conceptual splitting between a system-of-interest and its environment, and allows one to interpret any system as part of the environment of any other system. Finally, our approach leads to a full operational characterization of quantum discord in terms of local redistribution of correlations.
DOE Fundamentals Handbook: Classical Physics
Not Available
1992-06-01
The Classical Physics Fundamentals Handbook was developed to assist nuclear facility operating contractors provide operators, maintenance personnel, and the technical staff with the necessary fundamentals training to ensure a basic understanding of physical forces and their properties. The handbook includes information on the units used to measure physical properties; vectors, and how they are used to show the net effect of various forces; Newton's Laws of motion, and how to use these laws in force and motion applications; and the concepts of energy, work, and power, and how to measure and calculate the energy involved in various applications. This information will provide personnel with a foundation for understanding the basic operation of various types of DOE nuclear facility systems and equipment.
Classical mechanics of nonconservative systems.
Galley, Chad R
2013-04-26
Hamilton's principle of stationary action lies at the foundation of theoretical physics and is applied in many other disciplines from pure mathematics to economics. Despite its utility, Hamilton's principle has a subtle pitfall that often goes unnoticed in physics: it is formulated as a boundary value problem in time but is used to derive equations of motion that are solved with initial data. This subtlety can have undesirable effects. I present a formulation of Hamilton's principle that is compatible with initial value problems. Remarkably, this leads to a natural formulation for the Lagrangian and Hamiltonian dynamics of generic nonconservative systems, thereby filling a long-standing gap in classical mechanics. Thus, dissipative effects, for example, can be studied with new tools that may have applications in a variety of disciplines. The new formalism is demonstrated by two examples of nonconservative systems: an object moving in a fluid with viscous drag forces and a harmonic oscillator coupled to a dissipative environment.
Classically Stable Nonsingular Cosmological Bounces
NASA Astrophysics Data System (ADS)
Ijjas, Anna; Steinhardt, Paul J.
2016-09-01
One of the fundamental questions of theoretical cosmology is whether the Universe can undergo a nonsingular bounce, i.e., smoothly transit from a period of contraction to a period of expansion through violation of the null energy condition (NEC) at energies well below the Planck scale and at finite values of the scale factor such that the entire evolution remains classical. A common claim has been that a nonsingular bounce either leads to ghost or gradient instabilities or a cosmological singularity. In this Letter, we consider a well-motivated class of theories based on the cubic Galileon action and present a procedure for explicitly constructing examples of a nonsingular cosmological bounce without encountering any pathologies and maintaining a subluminal sound speed for comoving curvature modes throughout the NEC violating phase. We also discuss the relation between our procedure and earlier work.
Classically Stable Nonsingular Cosmological Bounces.
Ijjas, Anna; Steinhardt, Paul J
2016-09-16
One of the fundamental questions of theoretical cosmology is whether the Universe can undergo a nonsingular bounce, i.e., smoothly transit from a period of contraction to a period of expansion through violation of the null energy condition (NEC) at energies well below the Planck scale and at finite values of the scale factor such that the entire evolution remains classical. A common claim has been that a nonsingular bounce either leads to ghost or gradient instabilities or a cosmological singularity. In this Letter, we consider a well-motivated class of theories based on the cubic Galileon action and present a procedure for explicitly constructing examples of a nonsingular cosmological bounce without encountering any pathologies and maintaining a subluminal sound speed for comoving curvature modes throughout the NEC violating phase. We also discuss the relation between our procedure and earlier work.
Classical Cosmology Through Animation Stories
NASA Astrophysics Data System (ADS)
Mijic, Milan; Kang, E. Y. E.; Longson, T.; State LA SciVi Project, Cal
2010-05-01
Computer animations are a powerful tool for explanation and communication of ideas, especially to a younger generation. Our team completed a three part sequence of short, computer animated stories about the insight and discoveries that lead to the understanding of the overall structure of the universe. Our principal characters are Immanuel Kant, Henrietta Leavitt, and Edwin Hubble. We utilized animations to model and visualize the physical concepts behind each discovery and to recreate the characters, locations, and flavor of the time. The animations vary in length from 6 to 11 minutes. The instructors or presenters may wish to utilize them separately or together. The animations may be used for learning classical cosmology in a visual way in GE astronomy courses, in pre-college science classes, or in public science education setting.
Gamma Rays from Classical Novae
NASA Technical Reports Server (NTRS)
1997-01-01
NASA at the University of Chicago, provided support for a program of theoretical research into the nature of the thermonuclear outbursts of the classical novae and their implications for gamma ray astronomy. In particular, problems which have been addressed include the role of convection in the earliest stages of nova runaway, the influence of opacity on the characteristics of novae, and the nucleosynthesis expected to accompany nova outbursts on massive Oxygen-Neon-Magnesium (ONeMg) white dwarfs. In the following report, I will identify several critical projects on which considerable progress has been achieved and provide brief summaries of the results obtained:(1) two dimensional simulation of nova runaway; (2) nucleosynthesis of nova modeling; and (3) a quasi-analytic study of nucleosynthesis in ONeMg novae.
Gastrointestinal Health in Classic Galactosemia.
Shaw, Kelly A; Mulle, Jennifer G; Epstein, Michael P; Fridovich-Keil, Judith L
2016-07-01
Classic galactosemia (CG) is an autosomal recessive disorder of galactose metabolism that affects approximately 1/50,000 live births in the USA. Following exposure to milk, which contains large quantities of galactose, affected infants may become seriously ill. Early identification by newborn screening with immediate dietary galactose restriction minimizes or prevents the potentially lethal acute symptoms of CG. However, more than half of individuals with CG still experience long-term complications including cognitive disability, behavioral problems, and speech impairment. Anecdotal reports have also suggested frequent gastrointestinal (GI) problems, but this outcome has not been systematically addressed. In this study we explored the prevalence of GI symptoms among 183 children and adults with CG (cases) and 190 controls. Cases reported 4.5 times more frequent constipation (95% CI 1.8-11.5) and 4.2 times more frequent nausea (95% CI 1.2-15.5) than controls. Cases with genotypes predicting residual GALT activity reported less frequent constipation than cases without predicted GALT activity but this difference was not statistically significant. Because the rigor of dietary galactose restriction varies among individuals with galactosemia, we further tested whether GI symptoms associated with diet in infancy. Though constipation was almost four times as common among cases reporting a more restrictive diet in infancy, this difference was not statistically significant. These data confirm that certain GI symptoms are more common in classic galactosemia compared to controls and suggest that future studies should investigate associations with residual GALT activity and dietary galactose restriction in early life.
On Understanding a Sociological Classic
ERIC Educational Resources Information Center
Jones, Robert Alun
1977-01-01
Analyzes scholarly criticisms of "Elementary Forms of the Religious Life" by Emil Durkheim for the purpose of illustrating various approaches to sociological theory. Durkheim's theory of sacrifice is reinterpreted to serve as the basis for a new approach to the history of sociological theory. (Author/DB)
Zeng, L. W.; Singh, R. S.
1993-01-01
We have attempted to estimate the number of genes involved in postzygotic reproductive isolation between two closely related species, Drosophila simulans and Drosophila sechellia, by a novel approach that involves the use of high resolution two-dimensional gel electrophoresis (2DE) to examine testis proteins in parents, hybrids and fertile and sterile backcross progenies. The important results that have emerged from this study are as follows: (1) about 8% of about 1000 proteins examined showed divergence (presence/absence) between the two species; (2) by tracing individual proteins in parental, hybrid and backcross males, we were able to associate the divergent proteins with different chromosomes and found that most divergent proteins are associated with autosomes and very few with X chromosome, Y chromosome and cytoplasm; (3) when proteins showing both quantitative and qualitative differences between the two species were examined in F(1) hybrid males, most (97.4%) proteins were expressed at levels between the two parents and no sign of large scale changes in spot density was observed. All the proteins observed in the two parental species were present in F(1) hybrid males except two species-specific proteins that may be encoded (or regulated) by sex chromosomes; (4) when different fertile and sterile backcross male testes were compared, a few D. sechellia-specific proteins were identified to be consistently associated with male sterility. These results along with the observation that a large proportion (23.6%) of first generation backcross males were fertile show that hybrid male sterility between D. simulans and D. sechellia involves a relatively small number of genes. Role of large scale genetic changes due to general genome incompatibility is not supported. The results also suggest that the large effect of X chromosome on hybrid male sterility is not due to higher divergence of X chromosome than autosomes. PMID:8224814
Could a Mobile-Assisted Learning System Support Flipped Classrooms for Classical Chinese Learning?
ERIC Educational Resources Information Center
Wang, Y.-H.
2016-01-01
In this study, the researcher aimed to develop a mobile-assisted learning system and to investigate whether it could promote teenage learners' classical Chinese learning through the flipped classroom approach. The researcher first proposed the structure of the Cross-device Mobile-Assisted Classical Chinese (CMACC) system according to the pilot…
The Directedness of Time in Classical Cosmology
NASA Astrophysics Data System (ADS)
Bartels, Andreas; Wohlfarth, Daniel
2014-03-01
The aim of this paper is to show that a new understanding of fundamentality can be applied successfully in classical cosmology based on General Relativity. We are thereby able to achieve an account of cosmological time asymmetry as an intrinsic and fun-damental property of the universe. First, we consider Price's arguments against the fundamental status of time-asymmetry (Price (1996, 2002, 2011)). We show that these arguments have some force, but their force depends on understanding fundamentality as law-likeness. Second, we show that alternative approaches attempting to explain time directedness either by applying an anthropic strategy based on a multiverse approach, or by using the empirical fact of accelerated expansion of the universe, equally fail to provide a fundamental explanation of time directedness. In the third part, we present our own new concept of fundamentality based on properties of the solution space of fundamental laws. We demonstrate how this new concept of fundamentality is effective in understanding the cosmological asymmetry.
Classical vs. non-classical pathways of mineral formation (Invited)
NASA Astrophysics Data System (ADS)
De Yoreo, J. J.
2013-12-01
Recent chemical analyses, microscopy studies and computer simulations suggest many minerals nucleate through aggregation of pre-nucleation clusters and grow by particle-mediated processes that involve amorphous or disordered precursors. Still other analyses, both experimental and computational, conclude that even simple mineral systems like calcium carbonate form via a barrier-free process of liquid-liquid separation, which is followed by dehydration of the ion-rich phase to form the solid products. However, careful measurements of calcite nucleation rates on a variety of ionized surfaces give results that are in complete agreement with the expectations of classical nucleation theory, in which clusters growing through ion-by-ion addition overcome a free energy barrier through the natural microscopic density fluctuations of the system. Here the challenge of integrating these seemingly disparate observations and analyses into a coherent picture of mineral formation is addressed by considering the energy barriers to calcite formation predicted by the classical theory and the changes in those barriers brought about by the introduction of interfaces and clusters, both stable and metastable. Results from a suite of in situ TEM, AFM, and optical experiments combined with simulations are used to illustrate the conclusions. The analyses show that the expected barrier to homogeneous calcite nucleation is prohibitive even at concentrations exceeding the solubility limit of amorphous calcium carbonate. However, as demonstrated by experiments on self-assembled monolayers, the introduction of surfaces that moderately decrease the interfacial energy associated with the forming nucleus can reduce the magnitude of the barrier to a level that is easily surmounted under typical laboratory conditions. In the absence of such surfaces, experiments that proceed by continually increasing supersaturation with time can easily by-pass direct nucleation of calcite and open up pathways through
Open questions in classical gravity
Mannheim, P.D. )
1994-04-01
In this work, the authors discuss some outstanding open questions regarding the validity and uniqueness of the standard second-order Newton-Einstein classical gravitational theory. On the observational side the authors discuss the degree to which the realm of validity of Newton's law of gravity can actually be extended to distances much larger than the solar system distance scales on which the law was originally established. On the theoretical side the authors identify some commonly accepted (but actually still open to question) assumptions which go into the formulation of the standard second-order Einstein theory in the first place. In particular, it is shown that while the familiar second-order Poisson gravitational equation (and accordingly its second-order covariant Einstein generalization) may be sufficient to yield Newton's law of gravity they are not in fact necessary. The standard theory thus still awaits the identification of some principle which would then make it necessary too. It is shown that current observational information does not exclusively mandate the standard theory, and that the conformal invariant fourth-order theory of gravity considered recently by Mannheim and Kazanas is also able to meet the constraints of data, and in fact to do so without the need for any so far unobserved nonluminous or dark matter. 37 refs., 7 figs.
Relaxation properties in classical diamagnetism
NASA Astrophysics Data System (ADS)
Carati, A.; Benfenati, F.; Galgani, L.
2011-06-01
It is an old result of Bohr that, according to classical statistical mechanics, at equilibrium a system of electrons in a static magnetic field presents no magnetization. Thus a magnetization can occur only in an out of equilibrium state, such as that produced through the Foucault currents when a magnetic field is switched on. It was suggested by Bohr that, after the establishment of such a nonequilibrium state, the system of electrons would quickly relax back to equilibrium. In the present paper, we study numerically the relaxation to equilibrium in a modified Bohr model, which is mathematically equivalent to a billiard with obstacles, immersed in a magnetic field that is adiabatically switched on. We show that it is not guaranteed that equilibrium is attained within the typical time scales of microscopic dynamics. Depending on the values of the parameters, one has a relaxation either to equilibrium or to a diamagnetic (presumably metastable) state. The analogy with the relaxation properties in the Fermi Pasta Ulam problem is also pointed out.
Ordering in classical Coulombic systems.
Schiffer, J. P.
1998-01-22
The author discusses the properties of classical Coulombic matter at low temperatures. It has been well known for some time [1,2] that infinite Coulombic matter will crystallize in body-centered cubic form when the quantity {Lambda} (the dimensionless ratio of the average two-particle Coulomb energy to the kinetic energy per particle) is larger than {approximately}175. But the systems of such particles that have been produced in the laboratory in ion traps, or ion beams, are finite with surfaces defined by the boundary conditions that have to be satisfied. This results in ion clouds with sharply defined curved surfaces, and interior structures that show up as a set of concentric layers that are parallel to the outer surface. The ordering does not appear to be cubic, but the charges on each shell exhibit a ''hexatic'' pattern of equilateral triangles that is the characteristic of liquid crystals. The curvature of the surfaces prevents the structures on successive shells from interlocking in any simple fashion. This class of structures was first found in simulations [3] and later in experiments [4].
Structure of classical affine and classical affine fractional W-algebras
Suh, Uhi Rinn
2015-01-15
We introduce a classical BRST complex (See Definition 3.2.) and show that one can construct a classical affine W-algebra via the complex. This definition clarifies that classical affine W-algebras can be considered as quasi-classical limits of quantum affine W-algebras. We also give a definition of a classical affine fractional W-algebra as a Poisson vertex algebra. As in the classical affine case, a classical affine fractional W-algebra has two compatible λ-brackets and is isomorphic to an algebra of differential polynomials as a differential algebra. When a classical affine fractional W-algebra is associated to a minimal nilpotent, we describe explicit forms of free generators and compute λ-brackets between them. Provided some assumptions on a classical affine fractional W-algebra, we find an infinite sequence of integrable systems related to the algebra, using the generalized Drinfel’d and Sokolov reduction.
Classical underpinnings of gravitationally induced quantum interference
Mannheim, P.D.
1998-02-01
We show that the gravitational modification of the phase of a neutron beam [the Colella-Overhauser-Werner (COW) experiment] has a classical origin, being due to the time delay that classical particles experience in traversing a background gravitational field. Similarly, we show that classical light waves also undergo a phase shift in traversing a gravitational field. We show that the COW experiment respects the equivalence principle even in the presence of quantum mechanics. {copyright} {ital 1998} {ital The American Physical Society}
Technology Transfer Automated Retrieval System (TEKTRAN)
Controlling classical swine fever (CSF) involves vaccination in endemic regions and preemptive slaughter of infected swine herds during epidemics. Generally, live attenuated vaccines induce solid immunity. Using diverse approaches, reverse genetics has been useful in developing classical swine fever...
Classical teleportation of a quantum Bit
Cerf; Gisin; Massar
2000-03-13
Classical teleportation is defined as a scenario where the sender is given the classical description of an arbitrary quantum state while the receiver simulates any measurement on it. This scenario is shown to be achievable by transmitting only a few classical bits if the sender and receiver initially share local hidden variables. Specifically, a communication of 2.19 bits is sufficient on average for the classical teleportation of a qubit, when restricted to von Neumann measurements. The generalization to positive-operator-valued measurements is also discussed.
Classical Solution Thermodynamics: A Retrospective View.
ERIC Educational Resources Information Center
Van Ness, H. C.; Abbott, M. M.
1985-01-01
Examines topics related to classical solution thermodynamics, considering energy, enthalpy, and the Gibbs function. Applicable mathematical equations are introduced and discussed when appropriate. (JN)
Implementation of quantum and classical discrete fractional Fourier transforms.
Weimann, Steffen; Perez-Leija, Armando; Lebugle, Maxime; Keil, Robert; Tichy, Malte; Gräfe, Markus; Heilmann, René; Nolte, Stefan; Moya-Cessa, Hector; Weihs, Gregor; Christodoulides, Demetrios N; Szameit, Alexander
2016-03-23
Fourier transforms, integer and fractional, are ubiquitous mathematical tools in basic and applied science. Certainly, since the ordinary Fourier transform is merely a particular case of a continuous set of fractional Fourier domains, every property and application of the ordinary Fourier transform becomes a special case of the fractional Fourier transform. Despite the great practical importance of the discrete Fourier transform, implementation of fractional orders of the corresponding discrete operation has been elusive. Here we report classical and quantum optical realizations of the discrete fractional Fourier transform. In the context of classical optics, we implement discrete fractional Fourier transforms of exemplary wave functions and experimentally demonstrate the shift theorem. Moreover, we apply this approach in the quantum realm to Fourier transform separable and path-entangled biphoton wave functions. The proposed approach is versatile and could find applications in various fields where Fourier transforms are essential tools.
Implementation of quantum and classical discrete fractional Fourier transforms
Weimann, Steffen; Perez-Leija, Armando; Lebugle, Maxime; Keil, Robert; Tichy, Malte; Gräfe, Markus; Heilmann, René; Nolte, Stefan; Moya-Cessa, Hector; Weihs, Gregor; Christodoulides, Demetrios N.; Szameit, Alexander
2016-01-01
Fourier transforms, integer and fractional, are ubiquitous mathematical tools in basic and applied science. Certainly, since the ordinary Fourier transform is merely a particular case of a continuous set of fractional Fourier domains, every property and application of the ordinary Fourier transform becomes a special case of the fractional Fourier transform. Despite the great practical importance of the discrete Fourier transform, implementation of fractional orders of the corresponding discrete operation has been elusive. Here we report classical and quantum optical realizations of the discrete fractional Fourier transform. In the context of classical optics, we implement discrete fractional Fourier transforms of exemplary wave functions and experimentally demonstrate the shift theorem. Moreover, we apply this approach in the quantum realm to Fourier transform separable and path-entangled biphoton wave functions. The proposed approach is versatile and could find applications in various fields where Fourier transforms are essential tools. PMID:27006089
Quantum-classical electron distributions in atoms and atomic ions
NASA Technical Reports Server (NTRS)
Kunc, Joseph A.
1988-01-01
A quantum-classical approach is used to obtain the velocity distributions in atoms and positive and negative ions in both ground and excited states. In the analysis, Hartree-Fock electronic wavefunctions are used to determine the radial electron distributions, and the central-field approximation is used to study the the dynamic properties of the localized electrons. The distributions for the outer and inner shells are found to agree well with exact results obtained by numerical calculations.
Grid generation using classical techniques
NASA Technical Reports Server (NTRS)
Moretti, G.
1980-01-01
A brief historical review of conformal mapping and its applications to problems in fluid mechanics and electromagnetism is presented. The use of conformal mapping as a grid generator is described. The philosophy of the 'closed form' approach and its application to a Neumann problem is discussed. Karman-Trefftz mappings and grids for ablated, three dimensional bodies are also discussed.
ERIC Educational Resources Information Center
FORBES, MARGARET
THE ARTS AND HUMANITIES INSTITUTE FOR LATIN TEACHERS EMPHASIZED TEACHING TECHNIQUES, INSTRUCTIONAL MATERIALS FOR BEGINNING (SEVENTH-GRADE) LATIN CLASSES, AND IMPROVEMENT OF TEACHER PROFICIENCY IN LANGUAGE SKILLS. THE PARTICIPANTS CONSIDERED THE CONCURRENT APPROACH AND USE OF VISUAL, AURAL, PICTORIAL, AND KINETIC METHODS OF LANGUAGE INSTRUCTION.…
Classical and semiclassical aspects of chemical dynamics
Gray, S.K.
1982-08-01
Tunneling in the unimolecular reactions H/sub 2/C/sub 2/ ..-->.. HC/sub 2/H, HNC ..-->.. HCN, and H/sub 2/CO ..-->.. H/sub 2/ + CO is studied with a classical Hamiltonian that allows the reaction coordinate and transverse vibrational modes to be considered directly. A combination of classical perturbation theory and the semiclassical WKB method allows tunneling probabilities to be obtained, and a statistical theory (RRKM) is used to construct rate constants for these reactions in the tunneling regime. In this fashion, it is found that tunneling may be important, particularly for low excitation energies. Nonadiabatic charge transfer in the reaction Na + I ..-->.. Na /sup +/ + I/sup -/ is treated with classical trajectories based on a classical Hamiltonian that is the analogue of a quantum matrix representation. The charge transfer cross section obtained is found to agree reasonably well with the exact quantum results. An approximate semiclassical formula, valid at high energies, is also obtained. The interaction of radiation and matter is treated from a classical viewpoint. The excitation of an HF molecule in a strong laser is described with classical trajectories. Quantum mechanical results are also obtained and compared to the classical results. Although the detailed structure of the pulse time averaged energy absorption cannot be reproduced classically, classical mechanics does predict the correct magnitude of energy absorption, as well as certain other qualitative features. The classical behavior of a nonrotating diatomic molecule in a strong laser field is considered further, by generating a period advance map that allows the solution over many periods of oscillation of the laser to be obtained with relative ease. Classical states are found to form beautiful spirals in phase space as time progresses. A simple pendulum model is found to describe the major qualitative features. (WHM)
Kennedy and Achilles: A Classical Approach on Political Science.
ERIC Educational Resources Information Center
Nelson, Michael
1996-01-01
Uses the careers of President John F. Kennedy and the legendary Greek hero Achilles to explore the intersections among mythological status, public perception, and leadership. Observes fascinating parallels between both men and their roles as soldiers, generational representatives, and martyred heroes. (MJP)
Electromagnetic Induction in Rough Geologic Media: The Classical Approach
NASA Astrophysics Data System (ADS)
Weiss, C. J.; Everett, M. E.; Ge, J.
2012-12-01
Electromagnetic (EM) induction methods are well known to be sensitive indicators of electrically conducting subsurface mineral and fluid phases, responding to both the topological connectedness of the conducting phase and galvanic charge buildup on conductivity boundaries. Key to quantifying the relationship between electromagnetic signatures and the underlying the geohydrology is accurate representation of the infinitely complex, conducting Earth in terms of a finite set of model parameters and their associated physics. However, field observations of the spatial variability of induced EM fields and their inferred rate of diffusive propagation suggest that simple, piecewise smooth or continuous models of electrical conductivity -- as commonly depicted in numerical modeling -- may not fully capture the relevant electrodynamics in all geologic settings, especially those where the subsurface is characterized by multi-scale, hierarchical structures such as fractures. Consistent with such observations is a recasting of the Maxwell Equations in terms of fractional calculus, similar to that done routinely in hydrology for the transport equations to explain anomalous hydrologic diffusion, where the underlying multi-scale complexity is captured efficiently by only a few, simple, model parameters. This study focuses on how geo-complexity ultimately manifests its EM signature in a fractional-calculus sense through three-dimensional modeling of spatially-correlated stochastic realizations of the electrically conducting subsurface. Preliminary results simulating the response of a frequency-domain, loop-loop system suggest that heterogeneity proximal to the transmitting antenna generates a strong, but relatively smooth response in the near-field vertical magnetic induction when compared to that in the far field. This finding suggests an exploration strategy based on multi-offset observations may be relevant to quantifying the length scale over which the fractional calculus model holds.; Induced vertical magnetic induction, quadrature phase, surrounding a vertical magnetic dipole transmitter antenna located on Earth's surface, for two different model realizations: a homogeneous 0.1 S/m Earth (left), and a stochastic Earth with log-conductivity uniformly distributed on (-1.5,-0.5) log_10 S/m.
Pembrolizumab in classical Hodgkin’s lymphoma
Maly, Joseph; Alinari, Lapo
2016-01-01
Pembrolizumab is a humanized monoclonal antibody directed against programmed cell death protein 1 (PD-1), a key immune-inhibitory molecule expressed on T cells and implicated in CD4+ T-cell exhaustion and tumor immune-escape mechanisms. Classical Hodgkin’s lymphoma (cHL) is a unique B-cell malignancy in the sense that malignant Reed–Sternberg (RS) cells represent a small percentage of cells within an extensive immune cell infiltrate. PD-1 ligands are upregulated on RS cells as a consequence of both chromosome 9p24.1 amplification and Epstein–Barr virus infection and by interacting with PD-1 promote an immune-suppressive effect. By augmenting antitumor immune response, pembrolizumab and nivolumab, another monoclonal antibody against PD-1, have shown significant activity in patients with relapsed/refractory cHL as well as an acceptable toxicity profile with immune-related adverse events that are generally manageable. In this review, we explore the rationale for targeting PD-1 in cHL, review the clinical trial results supporting the use of checkpoint inhibitors in this disease, and present future directions for investigation in which this approach may be used. PMID:27147112
ERIC Educational Resources Information Center
Cartledge, Paul
2005-01-01
Classics is in the news--or on the screen: "Gladiator" a few years ago, "Troy" very recently, "Alexander" as I write. How significant is this current Hollywood fascination with the ancient Greeks and Romans? Or should we take far more seriously the decline of the teaching of the Classical languages in schools, a…
Velopharyngeal Port Status during Classical Singing
ERIC Educational Resources Information Center
Tanner, Kristine; Roy, Nelson; Merrill, Ray M.; Power, David
2005-01-01
Purpose: This investigation was undertaken to examine the status of the velopharyngeal (VP) port during classical singing. Method: Using aeromechanical instrumentation, nasal airflow (mL/s), oral pressure (cm H[subscript 2]O), and VP orifice area estimates (cm[squared]) were studied in 10 classically trained sopranos during singing and speaking.…
Tarnished Gold: Classical Music in America
ERIC Educational Resources Information Center
Asia, Daniel
2010-01-01
A few articles have appeared recently regarding the subject of the health of classical music (or more broadly, the fine arts) in America. These include "Classical Music's New Golden Age," by Heather Mac Donald, in the "City Journal" and "The Decline of the Audience," by Terry Teachout, in "Commentary." These articles appeared around the time of…
Linguistic Investigations into Ellipsis in Classical Sanskrit
NASA Astrophysics Data System (ADS)
Gillon, Brendan S.
Ellipsis is a common phenomenon of Classical Sanskrit prose. No inventory of the forms of ellipsis in Classical Sanskrit has been made. This paper presents an inventory, based both on a systematic investigation of one text and on examples based on sundry reading.
Converting Projects from STK Classic to STK
Foucar, James G.
2014-08-01
The version of STK (Sierra ToolKit) that has long been provided with Trilinos is no longer supported by the core develop- ment team. With the introduction of a the new STK library into Trilinos, the old STK has been renamed to stk classic. This document contains a rough guide of how to port a stk classic code to STK.
Classical and Quantum-Mechanical State Reconstruction
ERIC Educational Resources Information Center
Khanna, F. C.; Mello, P. A.; Revzen, M.
2012-01-01
The aim of this paper is to present the subject of state reconstruction in classical and in quantum physics, a subject that deals with the experimentally acquired information that allows the determination of the physical state of a system. Our first purpose is to explain a method for retrieving a classical state in phase space, similar to that…
Milgram's Obedience Study: A Contentious Classic Reinterpreted
ERIC Educational Resources Information Center
Griggs, Richard A.
2017-01-01
Given the many older criticisms of Milgram's obedience study and the more damning recent criticisms based on analyses of materials available in the Milgram archives at Yale, this study has become a contentious classic. Yet, current social psychology textbooks present it as an uncontentious classic, with no coverage of the recent criticisms and…
Factors Influencing the Learning of Classical Mechanics.
ERIC Educational Resources Information Center
Champagne, Audrey B.; And Others
1980-01-01
Describes a study investigating the combined effect of certain variables on student achievement in classical mechanics. The purpose was to (1) describe preinstructional knowledge and skills; (2) correlate these variables with the student's success in learning classical mechanics; and (3) develop hypothesis about relationships between these…
Classic and Romantic in Irish Curriculum Development.
ERIC Educational Resources Information Center
McKernan, Jim
Recent trends in curriculum development in Irish post-primary schools are traced according to two models: the classic-centrist and the romantic-decentralist. The classic model, initiated by agencies external to the school, views curriculum development as a science and focuses on accountability and competency-based teaching and testing. The…
The Classical Performing Arts of India.
ERIC Educational Resources Information Center
Curtiss, Marie Joy
A monograph of the numerous activities that have contributed to the current renaissance of India's classical performing arts covers the theoretical aspects, musical instruments, the main schools of classical dance, and drama. Besides the basic research described, the total project produced a set of 300 slides with annotated listing, picturing the…
A Classical Rhetoric for "Powerful" Argumentation.
ERIC Educational Resources Information Center
Wiethoff, William E.
1980-01-01
Analyzes a 1976 House of Representatives' debate in light of classical writings on the problem of defining and using "power" for rhetorical ends. Outlines the classical solution of powerful diction, brevity, and figures of speech for intensifying the impact of already compelling argument and applies these to the contemporary analysis.…
Quantum phase uncertainties in the classical limit
NASA Technical Reports Server (NTRS)
Franson, James D.
1994-01-01
Several sources of phase noise, including spontaneous emission noise and the loss of coherence due to which-path information, are examined in the classical limit of high field intensities. Although the origin of these effects may appear to be quantum-mechanical in nature, it is found that classical analogies for these effects exist in the form of chaos.
Classical transport in disordered systems
NASA Astrophysics Data System (ADS)
Papaioannou, Antonios
This thesis reports on the manifestation of structural disorder on molecular transport and it consists of two parts. Part I discusses the relations between classical transport and the underlying structural complexity of the system. Both types of molecular diffusion, namely Gaussian and non- Gaussian are presented and the relevant time regimes are discussed. In addition the concept of structural universality is introduced and connected with the diffusion metrics. One of the most robust techniques for measuring molecular mean square displacements is magnetic resonance. This method requires encoding and subsequently reading out after an experimentally controlled time, a phase φ to the spins using magnetic field gradients. The main limitation for probing short diffusion lengths L(t) ˜ 1micro m with magnetic resonance is the requirement to encode and decode the phase φ in very short time intervals. Therefore, to probe such displacements a special probe was developed equipped with a gradient coil capable of delivering magnetic field gradients of approximately 90 G/cmA . The design of the probe is reported. Part I also includes a discussion of experiments of transport in two qualitatively different disordered phantoms and reports on a direct observation of universality in one-dimension. The results reveal the universal power law scaling of the diffusion coefficient at the long-time regime and illustrate the essence of structural universality by experimentally determining the structure correlation function of the phantoms. In addition, the scaling of the diffusive permeability of the phantoms with respect to the pore size is investigated. Additional work presented includes a detailed study of adsorption of methane gas in Vycor disordered glass. The techniques described in Part I of this thesis are widely used for measuring structural parameters of porous media, such as the surface-to-volume ratio or diffusive permeability. Part II of this thesis discusses the
NUCLEAR THERMOMETERS FOR CLASSICAL NOVAE
Downen, Lori N.; Iliadis, Christian; Jose, Jordi; Starrfield, Sumner
2013-01-10
Classical novae are stellar explosions occurring in binary systems, consisting of a white dwarf and a main-sequence companion. Thermonuclear runaways on the surface of massive white dwarfs, consisting of oxygen and neon, are believed to reach peak temperatures of several hundred million kelvin. These temperatures are strongly correlated with the underlying white dwarf mass. The observational counterparts of such models are likely associated with outbursts that show strong spectral lines of neon in their shells (neon novae). The goals of this work are to investigate how useful elemental abundances are for constraining the peak temperatures achieved during these outbursts and determine how robust 'nova thermometers' are with respect to uncertain nuclear physics input. We present updated observed abundances in neon novae and perform a series of hydrodynamic simulations for several white dwarf masses. We find that the most useful thermometers, N/O, N/Al, O/S, S/Al, O/Na, Na/Al, O/P, and P/Al, are those with the steepest monotonic dependence on peak temperature. The sensitivity of these thermometers to thermonuclear reaction rate variations is explored using post-processing nucleosynthesis simulations. The ratios N/O, N/Al, O/Na, and Na/Al are robust, meaning they are minimally affected by uncertain rates. However, their dependence on peak temperature is relatively weak. The ratios O/S, S/Al, O/P, and P/Al reveal strong dependences on temperature and the poorly known {sup 30}P(p, {gamma}){sup 31}S rate. We compare our model predictions to neon nova observations and obtain the following estimates for the underlying white dwarf masses: 1.34-1.35 M {sub Sun} (V838 Her), 1.18-1.21 M {sub Sun} (V382 Vel), {<=}1.3 M {sub Sun} (V693 CrA), {<=}1.2 M {sub Sun} (LMC 1990 no. 1), and {<=}1.2 M {sub Sun} (QU Vul).
Quantum simulation of classical thermal states.
Dür, W; Van den Nest, M
2011-10-21
We establish a connection between ground states of local quantum Hamiltonians and thermal states of classical spin systems. For any discrete classical statistical mechanical model in any spatial dimension, we find an associated quantum state such that the reduced density operator behaves as the thermal state of the classical system. We show that all these quantum states are unique ground states of a universal 5-body local quantum Hamiltonian acting on a (polynomially enlarged) qubit system on a 2D lattice. The only free parameters of the quantum Hamiltonian are coupling strengths of two-body interactions, which allow one to choose the type and dimension of the classical model as well as the interaction strength and temperature. This opens the possibility to study and simulate classical spin models in arbitrary dimension using a 2D quantum system.
Representational Realism, Closed Theories and the Quantum to Classical Limit
NASA Astrophysics Data System (ADS)
de Ronde, Christian
In this chapter, we discuss the representational realist stance as a pluralistontic approach to inter-theoretic relationships. Our stance stresses the fact that physical theories require the necessary consideration of a conceptual level of discourse which determines and configures the specific field of phenomena discussed by each particular theory. We will criticize the orthodox line of research which has grounded the analysis about QM in two (Bohrian) metaphysical presuppositions - accepted in the present as dogmas that all interpretations must follow. We will also examine how the orthodox project of "bridging the gap" between the quantum and the classical domains has constrained the possibilities of research, producing only a limited set of interpretational problems which only focus in the justification of "classical reality" and exclude the possibility of analyzing the possibilities of non-classical conceptual representations of QM. The representational realist stance introduces two new problems, namely, the superposition problem and the contextuality problem, which consider explicitly the conceptual representation of orthodox QM beyond the mere reference to mathematical structures and measurement outcomes. In the final part of the chapter, we revisit, from representational realist perspective, the quantum to classical limit and the orthodox claim that this inter-theoretic relation can be explained through the principle of decoherence.
NASA Astrophysics Data System (ADS)
Uspenskiy, Igor; Strodel, Birgit; Stock, Gerhard
2006-10-01
The mapping formulation of nonadiabatic quantum dynamics is applied to obtain a classical description of the ultrafast dynamics and time-resolved spectroscopy of a photochemical reaction. Adopting a previously studied dissipative two-state two-mode model of nonadiabatic cis-trans photoisomerization, classical mapping simulations are compared to quantum-mechanical reduced density matrix calculations. Overall, the simple classical method is found to reproduce the quantum reference calculations quite well. In particular, it is studied if the classical approach yields the correct long-time cis/trans localization of the wave packet and therefore the correct quantum yield of the photoreaction. As the long-time behavior of the classical mapping formulation suffers from the well-known zero point energy problem of classical mechanics, a new practical method is proposed to determine a zero point energy correction. Employing a second-order Franck-Condon-type approximation, the capability of the classical method to simulate time- and frequency-resolved pump-probe spectra of the nonadiabatic photoreaction is studied. The potential of the classical approach as a practical method to describe condensed-phase photoreactions is discussed.
Driven topological systems in the classical limit
NASA Astrophysics Data System (ADS)
Duncan, Callum W.; Öhberg, Patrik; Valiente, Manuel
2017-03-01
Periodically driven quantum systems can exhibit topologically nontrivial behavior, even when their quasienergy bands have zero Chern numbers. Much work has been conducted on noninteracting quantum-mechanical models where this kind of behavior is present. However, the inclusion of interactions in out-of-equilibrium quantum systems can prove to be quite challenging. On the other hand, the classical counterpart of hard-core interactions can be simulated efficiently via constrained random walks. The noninteracting model, proposed by Rudner et al. [Phys. Rev. X 3, 031005 (2013), 10.1103/PhysRevX.3.031005], has a special point for which the system is equivalent to a classical random walk. We consider the classical counterpart of this model, which is exact at a special point even when hard-core interactions are present, and show how these quantitatively affect the edge currents in a strip geometry. We find that the interacting classical system is well described by a mean-field theory. Using this we simulate the dynamics of the classical system, which show that the interactions play the role of Markovian, or time-dependent disorder. By comparing the evolution of classical and quantum edge currents in small lattices, we find regimes where the classical limit considered gives good insight into the quantum problem.
Optimal control law for classical and multiconjugate adaptive optics.
Le Roux, Brice; Conan, Jean-Marc; Kulcsár, Caroline; Raynaud, Henri-François; Mugnier, Laurent M; Fusco, Thierry
2004-07-01
Classical adaptive optics (AO) is now a widespread technique for high-resolution imaging with astronomical ground-based telescopes. It generally uses simple and efficient control algorithms. Multiconjugate adaptive optics (MCAO) is a more recent and very promising technique that should extend the corrected field of view. This technique has not yet been experimentally validated, but simulations already show its high potential. The importance for MCAO of an optimal reconstruction using turbulence spatial statistics has already been demonstrated through open-loop simulations. We propose an optimal closed-loop control law that accounts for both spatial and temporal statistics. The prior information on the turbulence, as well as on the wave-front sensing noise, is expressed in a state-space model. The optimal phase estimation is then given by a Kalman filter. The equations describing the system are given and the underlying assumptions explained. The control law is then derived. The gain brought by this approach is demonstrated through MCAO numerical simulations representative of astronomical observation on a 8-m-class telescope in the near infrared. We also discuss the application of this control approach to classical AO. Even in classical AO, the technique could be relevant especially for future extreme AO systems.
Extension of the classical classification of β-turns
de Brevern, Alexandre G.
2016-01-01
The functional properties of a protein primarily depend on its three-dimensional (3D) structure. These properties have classically been assigned, visualized and analysed on the basis of protein secondary structures. The β-turn is the third most important secondary structure after helices and β-strands. β-turns have been classified according to the values of the dihedral angles φ and ψ of the central residue. Conventionally, eight different types of β-turns have been defined, whereas those that cannot be defined are classified as type IV β-turns. This classification remains the most widely used. Nonetheless, the miscellaneous type IV β-turns represent 1/3rd of β-turn residues. An unsupervised specific clustering approach was designed to search for recurrent new turns in the type IV category. The classical rules of β-turn type assignment were central to the approach. The four most frequently occurring clusters defined the new β-turn types. Unexpectedly, these types, designated IV1, IV2, IV3 and IV4, represent half of the type IV β-turns and occur more frequently than many of the previously established types. These types show convincing particularities, in terms of both structures and sequences that allow for the classical β-turn classification to be extended for the first time in 25 years. PMID:27627963
Nonequilibrium statistical field theory for classical particles: Basic kinetic theory.
Viermann, Celia; Fabis, Felix; Kozlikin, Elena; Lilow, Robert; Bartelmann, Matthias
2015-06-01
Recently Mazenko and Das and Mazenko [Phys. Rev. E 81, 061102 (2010); J. Stat. Phys. 149, 643 (2012); J. Stat. Phys. 152, 159 (2013); Phys. Rev. E 83, 041125 (2011)] introduced a nonequilibrium field-theoretical approach to describe the statistical properties of a classical particle ensemble starting from the microscopic equations of motion of each individual particle. We use this theory to investigate the transition from those microscopic degrees of freedom to the evolution equations of the macroscopic observables of the ensemble. For the free theory, we recover the continuity and Jeans equations of a collisionless gas. For a theory containing two-particle interactions in a canonical perturbation series, we find the macroscopic evolution equations to be described by the Born-Bogoliubov-Green-Kirkwood-Yvon hierarchy with a truncation criterion depending on the order in perturbation theory. This establishes a direct link between the classical and the field-theoretical approaches to kinetic theory that might serve as a starting point to investigate kinetic theory beyond the classical limits.
Extension of the classical classification of β-turns.
de Brevern, Alexandre G
2016-09-15
The functional properties of a protein primarily depend on its three-dimensional (3D) structure. These properties have classically been assigned, visualized and analysed on the basis of protein secondary structures. The β-turn is the third most important secondary structure after helices and β-strands. β-turns have been classified according to the values of the dihedral angles φ and ψ of the central residue. Conventionally, eight different types of β-turns have been defined, whereas those that cannot be defined are classified as type IV β-turns. This classification remains the most widely used. Nonetheless, the miscellaneous type IV β-turns represent 1/3(rd) of β-turn residues. An unsupervised specific clustering approach was designed to search for recurrent new turns in the type IV category. The classical rules of β-turn type assignment were central to the approach. The four most frequently occurring clusters defined the new β-turn types. Unexpectedly, these types, designated IV1, IV2, IV3 and IV4, represent half of the type IV β-turns and occur more frequently than many of the previously established types. These types show convincing particularities, in terms of both structures and sequences that allow for the classical β-turn classification to be extended for the first time in 25 years.
Survival of classic cholera in Bangladesh.
Siddique, A K; Baqui, A H; Eusof, A; Haider, K; Hossain, M A; Bashir, I; Zaman, K
1991-05-11
During the present cholera pandemic the El Tor biotype of Vibrio cholerae has completely displaced the classic biotype, except in Bangladesh. We studied the distribution of these two biotypes in twenty-four rural districts during epidemics in 1988-89; there was clustering of the classic biotype in the southern region and of the El Tor biotype in all other regions. These findings suggest that the southern coastal region is now (and may always have been) the habitat of classic cholera. The selective distribution of V cholerae O1 biotypes in Bangladesh may have been affected by ecological changes occurring in the country.
Failure of classical elasticity in auxetic foams
NASA Astrophysics Data System (ADS)
Roh, J. H.; Giller, C. B.; Mott, P. H.; Roland, C. M.
2013-04-01
Poisson's ratio, ν, was measured for four materials, a rubbery polymer, a conventional soft foam, and two auxetic foams. We find that for the first two materials, having ν ≥ 0.2, the experimental determinations of Poisson's ratio are in good agreement with values calculated from the shear and tensile moduli using the equations of classical elasticity. However, for the two auxetic materials (ν < 0), the equations of classical elasticity give values significantly different from the measured ν. We offer an interpretation of these results based on a recently published analysis of the bounds on Poisson's ratio for classical elasticity to be applicable.
Coherent quantum states from classical oscillator amplitudes
NASA Astrophysics Data System (ADS)
Briggs, John S.; Eisfeld, Alexander
2012-05-01
In the first days of quantum mechanics Dirac pointed out an analogy between the time-dependent coefficients of an expansion of the Schrödinger equation and the classical position and momentum variables solving Hamilton's equations. Here it is shown that the analogy can be made an equivalence in that, in principle, systems of classical oscillators can be constructed whose position and momenta variables form time-dependent amplitudes which are identical to the complex quantum amplitudes of the coupled wave function of an N-level quantum system with real coupling matrix elements. Hence classical motion can reproduce quantum coherence.
A model for explaining fusion suppression using classical trajectory method
NASA Astrophysics Data System (ADS)
Phookan, C. K.; Kalita, K.
2015-01-01
We adopt a semi-classical approach for explanation of projectile breakup and above barrier fusion suppression for the reactions 6Li+152Sm and 6Li+144Sm. The cut-off impact parameter for fusion is determined by employing quantum mechanical ideas. Within this cut-off impact parameter for fusion, the fraction of projectiles undergoing breakup is determined using the method of classical trajectory in two-dimensions. For obtaining the initial conditions of the equations of motion, a simplified model of the 6Li nucleus has been proposed. We introduce a simple formula for explanation of fusion suppression. We find excellent agreement between the experimental and calculated fusion cross section. A slight modification of the above formula for fusion suppression is also proposed for a three-dimensional model.
Mixed quantum-classical equilibrium in global flux surface hopping
Sifain, Andrew E.; Wang, Linjun; Prezhdo, Oleg V.
2015-06-14
Global flux surface hopping (GFSH) generalizes fewest switches surface hopping (FSSH)—one of the most popular approaches to nonadiabatic molecular dynamics—for processes exhibiting superexchange. We show that GFSH satisfies detailed balance and leads to thermodynamic equilibrium with accuracy similar to FSSH. This feature is particularly important when studying electron-vibrational relaxation and phonon-assisted transport. By studying the dynamics in a three-level quantum system coupled to a classical atom in contact with a classical bath, we demonstrate that both FSSH and GFSH achieve the Boltzmann state populations. Thermal equilibrium is attained significantly faster with GFSH, since it accurately represents the superexchange process. GFSH converges closer to the Boltzmann averages than FSSH and exhibits significantly smaller statistical errors.
The Classical Arabinogalactan Protein Gene Family of Arabidopsis
Schultz, Carolyn J.; Johnson, Kim L.; Currie, Graeme; Bacic, Antony
2000-01-01
Arabinogalactan proteins (AGPs) are extracellular proteoglycans implicated in plant growth and development. We searched for classical AGPs in Arabidopsis by identifying expressed sequence tags based on the conserved domain structure of the predicted protein backbone. To confirm that these genes encoded bona fide AGPs, we purified native AGPs and then deglycosylated and deblocked them for N-terminal protein sequencing. In total, we identified 15 genes encoding the protein backbones of classical AGPs, including genes for AG peptides—AGPs with very short backbones (10 to 13 amino acid residues). Seven of the AGPs were verified as AGPs by protein sequencing. A gene encoding a putative cell adhesion molecule with AGP-like domains was also identified. This work provides a firm foundation for beginning functional analysis by using a genetic approach. PMID:11006345
Quantum-to-classical transition in cavity quantum electrodynamics.
Fink, J M; Steffen, L; Studer, P; Bishop, Lev S; Baur, M; Bianchetti, R; Bozyigit, D; Lang, C; Filipp, S; Leek, P J; Wallraff, A
2010-10-15
The quantum properties of electromagnetic, mechanical or other harmonic oscillators can be revealed by investigating their strong coherent coupling to a single quantum two level system in an approach known as cavity quantum electrodynamics (QED). At temperatures much lower than the characteristic energy level spacing the observation of vacuum Rabi oscillations or mode splittings with one or a few quanta asserts the quantum nature of the oscillator. Here, we study how the classical response of a cavity QED system emerges from the quantum one when its thermal occupation-or effective temperature-is raised gradually over 5 orders of magnitude. In this way we explore in detail the continuous quantum-to-classical crossover and demonstrate how to extract effective cavity field temperatures from both spectroscopic and time-resolved vacuum Rabi measurements.
The Invention of Infertility in the Classical Greek World:
Flemming, Rebecca
2013-01-01
Summary The article examines the understandings of, and responses to, reproductive failure in the classical Greek world. It discusses explanations and treatments for non-procreation in a range of ancient Greek medical texts, focusing on the writings of the Hippocratic Corpus, which devote considerable energy to matters of fertility and generation, and places them alongside the availability of a divine approach to dealing with reproductive disruption, the possibility of asking various deities, including the specialist healing god Asclepius, for assistance in having children. Though the relations between these options are complex, they combine to produce a rich remedial array for those struggling with childlessness, the possibility that any impediment to procreation can be removed. Classical Greece, rather than the nineteenth century, or even 1978, is thus the time when “infertility,” understood as an essentially reversible somatic state, was invented. PMID:24362276
Quantum physics of classical waves in plasma
NASA Astrophysics Data System (ADS)
Dodin, I. Y.
2012-10-01
The Lagrangian approach to plasma wave physics is extended to a universal nonlinear theory which yields generic equations invariant with respect to the wave nature. The traditional understanding of waves as solutions of the Maxwell-Vlasov system is abandoned. Oscillations are rather treated as physical entities, namely, abstract vectors |ψ> in a specific Hilbert space. The invariant product <ψ|ψ> is the total action and has the sign of the oscillation energy. The action density is then an operator. Projections of the corresponding operator equation generate assorted wave kinetic equations; the nonlinear Wigner-Moyal equation is just one example and, in fact, may be more delicate than commonly assumed. The linear adiabatic limit of this classical theory leads to quantum mechanics in its general form. The action conservation theorem, together with its avatars such as Manley-Rowe relations, then becomes manifest and in partial equilibrium can modify statistical properties of plasma fluctuations. In the quasi-monochromatic limit geometrical optics (GO) is recovered and can as well be understood as a particular field theory in its own right. For linear waves, the energy-momentum equations, in both canonical and (often) kinetic form, then follow automatically, even without a reference to electromagnetism. Yet for waves in plasma the general GO Lagrangian is also derived explicitly, in terms of single-particle oscillation-center Hamiltonians. Applications to various plasma waves are then discussed with an emphasis on the advantages of an abstract theory. Specifically covered are nonlinear dispersion, dynamics, and stability of BGK modes, and also other wave transformations in laboratory and cosmological plasmas.
A classical case of the Gasul phenomenon.
Sabnis, Girish R; Phadke, Milind S; Kerkar, Prafulla G
2016-02-01
This case demonstrates the development of secondary infundibular stenosis in a 10-year-old male child with documented large non-restrictive perimembranous ventricular septal defect in infancy - the classical Gasul phenomenon.
Classic Phenylketonuria: Diagnosis Through Heterozygote Detection
ERIC Educational Resources Information Center
Griffin, Robert F.; Elsas, Louis J.
1975-01-01
In an attempt to improve the identification of the asymptomatic carrier of classic phenylketonuria (PKU) 59 male and female normal control Ss were differentiated from 18 males and females heterozgous for PKU. (DB)
Secure quantum communication using classical correlated channel
NASA Astrophysics Data System (ADS)
Costa, D.; de Almeida, N. G.; Villas-Boas, C. J.
2016-10-01
We propose a secure protocol to send quantum information from one part to another without a quantum channel. In our protocol, which resembles quantum teleportation, a sender (Alice) and a receiver (Bob) share classical correlated states instead of EPR ones, with Alice performing measurements in two different bases and then communicating her results to Bob through a classical channel. Our secure quantum communication protocol requires the same amount of classical bits as the standard quantum teleportation protocol. In our scheme, as in the usual quantum teleportation protocol, once the classical channel is established in a secure way, a spy (Eve) will never be able to recover the information of the unknown quantum state, even if she is aware of Alice's measurement results. Security, advantages, and limitations of our protocol are discussed and compared with the standard quantum teleportation protocol.
Three Neglected Advances in Classical Genetics.
ERIC Educational Resources Information Center
Miller, Wilmer J.; Hollander, Willard F.
1995-01-01
This article describes three advances in classical genetics: improved pedigree charting, use of a standard of reference, and calculation of probabilities in complex assortment. Provides support for the importance of teaching these methods in addition to new techniques. (LZ)
Classical decoherence in a nanomechanical resonator
NASA Astrophysics Data System (ADS)
Maillet, Olivier; Fefferman, Andrew; Gazizulin, Rasul; Godfrin, Henri; Bourgeois, Olivier; Collin, Eddy; ULT Grenoble Team
Decoherence can be viewed either in its quantum picture, where it stands for the loss of phase coherence of a superposition state, or as its classical equivalent, where the phase of an oscillating signal is smeared due to frequency fluctuations. Little is known about quantum coherence of mechanical systems, as opposed to electromagnetic degrees of freedom. Indeed the bridge between quantum and classical physics is under intense investigation, using in particular classical nanomechanical analogues of quantum phenomena. Here we report on a model experiment in which the coherence of a high quality silicon-nitride mechanical resonator is defined in the classical picture. Its intrinsic properties are characterized over an unprecedentedly large dynamic range. By engineering frequency fluctuations, we can create artificial pure dephasing and study its effects on the dynamics of the system. Finally, we develop the methods to characterize pure dephasing that can be applied to a wide range of mechanical devices.
Classical and Quantum Spreading of Position Probability
ERIC Educational Resources Information Center
Farina, J. E. G.
1977-01-01
Demonstrates that the standard deviation of the position probability of a particle moving freely in one dimension is a function of the standard deviation of its velocity distribution and time in classical or quantum mechanics. (SL)
Classics in the Classroom: Great Expectations Fulfilled.
ERIC Educational Resources Information Center
Pearl, Shela
1986-01-01
Describes how an English teacher in a Queens, New York, ghetto school introduced her grade nine students to Charles Dickens's "Great Expectations." Focuses on students' responses, which eventually became enthusiastic, and discusses the use of classics within the curriculum. (KH)
Factorizations of one-dimensional classical systems
Kuru, Senguel; Negro, Javier
2008-02-15
A class of one-dimensional classical systems is characterized from an algebraic point of view. The Hamiltonians of these systems are factorized in terms of two functions that together with the Hamiltonian itself close a Poisson algebra. These two functions lead directly to two time-dependent integrals of motion from which the phase motions are derived algebraically. The systems so obtained constitute the classical analogues of the well known factorizable one-dimensional quantum mechanical systems.
Understanding singularities — Classical and quantum
NASA Astrophysics Data System (ADS)
Konkowski, Deborah A.; Helliwell, Thomas M.
2016-01-01
The definitions of classical and quantum singularities are reviewed. Examples are given of both as well as their utility in general relativity. In particular, the classical and quantum singularity structure of certain interesting conformally static spherically symmetric spacetimes modeling scalar field collapse are reviewed. The spacetimes include the Roberts spacetime, the Husain-Martinez-Nuñez spacetime and the Fonarev spacetime. The importance of understanding spacetime singularity structure is discussed.
Quantum Simulations of Classical Annealing Processes
NASA Astrophysics Data System (ADS)
Somma, R. D.; Boixo, S.; Barnum, H.; Knill, E.
2008-09-01
We describe a quantum algorithm that solves combinatorial optimization problems by quantum simulation of a classical simulated annealing process. Our algorithm exploits quantum walks and the quantum Zeno effect induced by evolution randomization. It requires order 1/δ steps to find an optimal solution with bounded error probability, where δ is the minimum spectral gap of the stochastic matrices used in the classical annealing process. This is a quadratic improvement over the order 1/δ steps required by the latter.
Quantization of the Maxwell fish-eye problem and the quantum-classical correspondence
Makowski, A. J.; Gorska, K. J.
2009-05-15
The so-called fish-eye model, originally investigated by Maxwell in geometrical optics, is studied both in the classical as well as in the quantum formulations. The best agreement between the two approaches is achieved by using a suitably constructed coherent state, which is of the SU(2) type. The perfect quantum-classical correspondence is obtained in the sense that classical rays go exactly over maxima of the corresponding quantum probability distributions. The distributions are made of linear combinations of the E=0 bound states of the considered model.
ERIC Educational Resources Information Center
Segev, Arik
2017-01-01
Phillip Cam recently published a study on the separation between the teaching and learning of classic school curriculum (CSC) on the one hand and morality on the other. He suggests an approach to integrate them. The goal of this article was to suggest a complementary alternative approach, to Cam's. Based on a MacIntyrean paradigm, I argue that…
Girl of Your Dreams or Bride of Frankenstein? Teaching Classical Mythology.
ERIC Educational Resources Information Center
DeBloois, Nanci
1998-01-01
Considers an approach to teaching classical mythology that focuses on the myth as a form of metaphor that communicates a universal truth through the themes and characters of the story. Applies this approach to the story of Pygmalion and Galatea and highlights both early and modern versions of the myth. (CMK)
DYNAMIC AND CLASSICAL PRA: A BWR SBO CASE COMPARISON
Mandelli, Diego; Smith, Curtis L; Ma, Zhegang
2011-07-01
As part of the Light-Water Sustainability Program (LWRS), the purpose of the Risk Informed Safety Margin Characterization (RISMC) Pathway research and development is to support plant decisions for risk-informed margin management with the aim to improve economics, reliability, and sustain the safety of current NPPs. In this paper, we describe the RISMC analysis process illustrating how mechanistic (i.e., dynamic system simulators) and probabilistic (stochastic sampling strategies) approaches are combined in a dynamic PRA fashion in order to estimate safety margins. We use the scenario of a “station blackout” (SBO) wherein offsite power and onsite power are lost, thereby causing a challenge to plant safety systems. We describe the RISMC approach, illustrate the station blackout modeling, and compare this with traditional risk analysis modeling for this type of accident scenario. In the RISMC approach the dataset obtained consists of set of simulation runs (performed by using codes such as RELAP5/3D) where timing and ordering of events is changed accordingly to the stochastic sampling strategy adopted. On the other side, classical PRA methods, which are based on event-tree (FT) and fault-tree (FT) structures, generate minimal cut sets and probability values associated to each ET branch. The comparison of the classical and RISMC approaches is performed not only in terms of overall core damage probability but also considering statistical differences in the actual sequence of events. The outcome of this comparison analysis shows similarities and dissimilarities between the approaches but also highlights the greater amount of information that can be generated by using the RISMC approach.
Activity Patterns in Latissimus Dorsi and Sternocleidomastoid in Classical Singers
Watson, Alan H.D.; Williams, Caitlin; James, Buddug V.
2012-01-01
Summary Objectives The aim of this study was to investigate and compare the roles of the accessory respiratory muscles, latissimus dorsi (LD), and sternocleidomastoid, in classical singing. Methods Electromyography was used to record the activity of these muscles in six classically trained female singers carrying out a number of singing and nonsinging tasks. Movements of the chest and abdominal walls were monitored simultaneously using inductive plethysmography, and the sound of the phonations was recorded. Results In normal breathing, LD is active transiently during very deep inhalations and in inhalation against resistance. During exhalation it becomes active again as residual capacity is approached or when air is expelled with great force. Sternocleidomastoid (SCM) supports inhalation when lung volume nears 100% vital capacity or when this is very rapid. All singers engaged LD in supported singing where it was associated with maintaining an expanded thorax. In coloratura singing, pulses of activity of increasing amplitude were often seen in LD toward the end of the breath. These were synchronized with each note. During a short phrase typical of the end of an aria, which was sung at full volume with the projected voice, both LD and SCM were active simultaneously. Spectral analysis of muscle activity demonstrated that in some singers, activity in LD and more rarely SCM, fluctuated in phase with vibrato. Conclusions LD appears to play a significant role in maintaining chest expansion and the dynamic processes underlying vibrato and coloratura singing in classically trained singers. PMID:21724365
Quantum-to-classical crossover near quantum critical point
Vasin, M.; Ryzhov, V.; Vinokur, V. M.
2015-12-21
A quantum phase transition (QPT) is an inherently dynamic phenomenon. However, while non-dissipative quantum dynamics is described in detail, the question, that is not thoroughly understood is how the omnipresent dissipative processes enter the critical dynamics near a quantum critical point (QCP). Here we report a general approach enabling inclusion of both adiabatic and dissipative processes into the critical dynamics on the same footing. We reveal three distinct critical modes, the adiabatic quantum mode (AQM), the dissipative classical mode [classical critical dynamics mode (CCDM)], and the dissipative quantum critical mode (DQCM). We find that as a result of the transitionmore » from the regime dominated by thermal fluctuations to that governed by the quantum ones, the system acquires effective dimension d+zΛ(T), where z is the dynamical exponent, and temperature-depending parameter Λ(T)ε[0, 1] decreases with the temperature such that Λ(T=0) = 1 and Λ(T →∞) = 0. Lastly, our findings lead to a unified picture of quantum critical phenomena including both dissipation- and dissipationless quantum dynamic effects and offer a quantitative description of the quantum-to-classical crossover.« less
Quantum-to-classical crossover near quantum critical point
Vasin, M.; Ryzhov, V.; Vinokur, V. M.
2015-01-01
A quantum phase transition (QPT) is an inherently dynamic phenomenon. However, while non-dissipative quantum dynamics is described in detail, the question, that is not thoroughly understood is how the omnipresent dissipative processes enter the critical dynamics near a quantum critical point (QCP). Here we report a general approach enabling inclusion of both adiabatic and dissipative processes into the critical dynamics on the same footing. We reveal three distinct critical modes, the adiabatic quantum mode (AQM), the dissipative classical mode [classical critical dynamics mode (CCDM)], and the dissipative quantum critical mode (DQCM). We find that as a result of the transition from the regime dominated by thermal fluctuations to that governed by the quantum ones, the system acquires effective dimension d + zΛ(T), where z is the dynamical exponent, and temperature-depending parameter Λ(T) ∈ [0, 1] decreases with the temperature such that Λ(T = 0) = 1 and Λ(T → ∞) = 0. Our findings lead to a unified picture of quantum critical phenomena including both dissipation- and dissipationless quantum dynamic effects and offer a quantitative description of the quantum-to-classical crossover. PMID:26688102
Quantum-to-classical crossover near quantum critical point
Vasin, M.; Ryzhov, V.; Vinokur, V. M.
2015-12-21
A quantum phase transition (QPT) is an inherently dynamic phenomenon. However, while non-dissipative quantum dynamics is described in detail, the question, that is not thoroughly understood is how the omnipresent dissipative processes enter the critical dynamics near a quantum critical point (QCP). Here we report a general approach enabling inclusion of both adiabatic and dissipative processes into the critical dynamics on the same footing. We reveal three distinct critical modes, the adiabatic quantum mode (AQM), the dissipative classical mode [classical critical dynamics mode (CCDM)], and the dissipative quantum critical mode (DQCM). We find that as a result of the transition from the regime dominated by thermal fluctuations to that governed by the quantum ones, the system acquires effective dimension d+zΛ(T), where z is the dynamical exponent, and temperature-depending parameter Λ(T)ε[0, 1] decreases with the temperature such that Λ(T=0) = 1 and Λ(T →∞) = 0. Lastly, our findings lead to a unified picture of quantum critical phenomena including both dissipation- and dissipationless quantum dynamic effects and offer a quantitative description of the quantum-to-classical crossover.
Quantum-to-classical crossover near quantum critical point.
Vasin, M; Ryzhov, V; Vinokur, V M
2015-12-21
A quantum phase transition (QPT) is an inherently dynamic phenomenon. However, while non-dissipative quantum dynamics is described in detail, the question, that is not thoroughly understood is how the omnipresent dissipative processes enter the critical dynamics near a quantum critical point (QCP). Here we report a general approach enabling inclusion of both adiabatic and dissipative processes into the critical dynamics on the same footing. We reveal three distinct critical modes, the adiabatic quantum mode (AQM), the dissipative classical mode [classical critical dynamics mode (CCDM)], and the dissipative quantum critical mode (DQCM). We find that as a result of the transition from the regime dominated by thermal fluctuations to that governed by the quantum ones, the system acquires effective dimension d + zΛ(T), where z is the dynamical exponent, and temperature-depending parameter Λ(T) ∈ [0, 1] decreases with the temperature such that Λ(T = 0) = 1 and Λ(T → ∞) = 0. Our findings lead to a unified picture of quantum critical phenomena including both dissipation- and dissipationless quantum dynamic effects and offer a quantitative description of the quantum-to-classical crossover.
Decoherence control in open quantum systems via classical feedback
NASA Astrophysics Data System (ADS)
Ganesan, Narayan; Tarn, Tzyh-Jong
2007-03-01
In this work we propose a strategy using techniques from systems theory to completely eliminate decoherence and also provide conditions under which it can be done. A construction employing an auxiliary system, the bait, which is instrumental to decoupling the system from the environment is presented. Our approach to decoherence control in contrast to other approaches in the literature involves the bilinear input affine model of quantum control system which lends itself to various techniques from classical control theory, but with nontrivial modifications to the quantum regime. The elegance of this approach yields interesting results on open loop decouplability and decoherence free subspaces. Additionally, the feedback control of decoherence may be related to disturbance decoupling for classical input affine systems, which entails careful application of the methods by avoiding all the quantum mechanical pitfalls. In the process of calculating a suitable feedback the system must be restructured due to its tensorial nature of interaction with the environment, which is unique to quantum systems. In the subsequent section we discuss a general information extraction scheme to gain knowledge of the state and the amount of decoherence based on indirect continuous measurement. The analysis of continuous measurement on a decohering quantum system has not been extensively studied before. Finally, a methodology to synthesize feedback parameters itself is given, that technology permitting, could be implemented for practical 2-qubit systems to perform decoherence free quantum computing. The results obtained are qualitatively different and superior to the ones obtained via master equations.
Unraveling Quantum Annealers using Classical Hardness.
Martin-Mayor, Victor; Hen, Itay
2015-10-20
Recent advances in quantum technology have led to the development and manufacturing of experimental programmable quantum annealing optimizers that contain hundreds of quantum bits. These optimizers, commonly referred to as 'D-Wave' chips, promise to solve practical optimization problems potentially faster than conventional 'classical' computers. Attempts to quantify the quantum nature of these chips have been met with both excitement and skepticism but have also brought up numerous fundamental questions pertaining to the distinguishability of experimental quantum annealers from their classical thermal counterparts. Inspired by recent results in spin-glass theory that recognize 'temperature chaos' as the underlying mechanism responsible for the computational intractability of hard optimization problems, we devise a general method to quantify the performance of quantum annealers on optimization problems suffering from varying degrees of temperature chaos: A superior performance of quantum annealers over classical algorithms on these may allude to the role that quantum effects play in providing speedup. We utilize our method to experimentally study the D-Wave Two chip on different temperature-chaotic problems and find, surprisingly, that its performance scales unfavorably as compared to several analogous classical algorithms. We detect, quantify and discuss several purely classical effects that possibly mask the quantum behavior of the chip.
The classical model for moment tensors
NASA Astrophysics Data System (ADS)
Tape, W.; Tape, C.
2013-12-01
A seismic moment tensor is a description of an earthquake source, but the description is indirect. The moment tensor describes seismic radiation rather than the actual physical process that initiates the radiation. A moment tensor 'model' then ties the physical process to the moment tensor. The model is not unique, and the physical process is therefore not unique. In the classical moment tensor model (Aki and Richards, 1980), an earthquake arises from slip along a planar fault, but with the slip not necessarily in the plane of the fault. The model specifies the resulting moment tensor in terms of the slip vector, the fault normal vector, and the Lame elastic parameters, assuming isotropy. We review the classical model in the context of the fundamental lune. The lune is closely related to the space of moment tensors, and it provides a setting that is conceptually natural as well as pictorial. In addition to the classical model, we consider a crack plus double couple model (CDC model) in which a moment tensor is regarded as the sum of a crack tensor and a double couple. A compilation of full moment tensors from the literature reveals large deviations in Poisson's ratio as implied by the classical model. Either the classical model is inadequate or the published full moment tensors have very large uncertainties. We question the common interpretation of the isotropic component as a volume change in the source region.
Effective dynamics of a classical point charge
Polonyi, Janos
2014-03-15
The effective Lagrangian of a point charge is derived by eliminating the electromagnetic field within the framework of the classical closed time path formalism. The short distance singularity of the electromagnetic field is regulated by an UV cutoff. The Abraham–Lorentz force is recovered and its similarity to quantum anomalies is underlined. The full cutoff-dependent linearized equation of motion is obtained, no runaway trajectories are found but the effective dynamics shows acausality if the cutoff is beyond the classical charge radius. The strength of the radiation reaction force displays a pole in its cutoff-dependence in a manner reminiscent of the Landau-pole of perturbative QED. Similarity between the dynamical breakdown of the time reversal invariance and dynamical symmetry breaking is pointed out. -- Highlights: •Extension of the classical action principle for dissipative systems. •New derivation of the Abraham–Lorentz force for a point charge. •Absence of a runaway solution of the Abraham–Lorentz force. •Acausality in classical electrodynamics. •Renormalization of classical electrodynamics of point charges.
Quantum-classical crossover in electrodynamics
Polonyi, Janos
2006-09-15
A classical field theory is proposed for the electric current and the electromagnetic field interpolating between microscopic and macroscopic domains. It represents a generalization of the density functional for the dynamics of the current and the electromagnetic field in the quantum side of the crossover and reproduces standard classical electrodynamics on the other side. The effective action derived in the closed time path formalism and the equations of motion follow from the variational principle. The polarization of the Dirac-sea can be taken into account in the quadratic approximation of the action by the introduction of the deplacement field strengths as in conventional classical electrodynamics. Decoherence appears naturally as a simple one-loop effect in this formalism. It is argued that the radiation time arrow is generated from the quantum boundary conditions in time by decoherence at the quantum-classical crossover and the Abraham-Lorentz force arises from the accelerating charge or from other charges in the macroscopic or the microscopic side, respectively. The functional form of the quantum renormalization group, the generalization of the renormalization group method for the density matrix, is proposed to follow the scale dependence through the quantum-classical crossover in a systematical manner.
Multipath Metropolis simulation: An application to the classical Heisenberg model
NASA Astrophysics Data System (ADS)
Rakić, Predrag S.; Radošević, Slobodan M.; Mali, Petar M.; Stričević, Lazar M.; Petrić, Tara D.
2016-01-01
This study explores the Multipath Metropolis simulation of the classical Heisenberg model. Unlike the standard single-path algorithm, the Metropolis algorithm applied to multiple random-walk paths becomes an embarrassingly parallel algorithm in which many processor cores can be easily utilized. This is important since processor cores are progressively becoming less expensive and thus more accessible. The most obvious advantage of the multipath approach is in employing independent random-walk paths to produce an uncorrelated simulation output with a normal distribution allowing for straightforward and rigorous statistical analysis.
Non-Classical Inhibition of Carbonic Anhydrase
Lomelino, Carrie L.; Supuran, Claudiu T.; McKenna, Robert
2016-01-01
Specific isoforms from the carbonic anhydrase (CA) family of zinc metalloenzymes have been associated with a variety of diseases. Isoform-specific carbonic anhydrase inhibitors (CAIs) are therefore a major focus of attention for specific disease treatments. Classical CAIs, primarily sulfonamide-based compounds and their bioisosteres, are examined as antiglaucoma, antiepileptic, antiobesity, antineuropathic pain and anticancer compounds. However, many sulfonamide compounds inhibit all CA isoforms nonspecifically, diluting drug effectiveness and causing undesired side effects due to off-target inhibition. In addition, a small but significant percentage of the general population cannot be treated with sulfonamide-based compounds due to a sulfa allergy. Therefore, CAIs must be developed that are not only isoform specific, but also non-classical, i.e. not based on sulfonamides, sulfamates, or sulfamides. This review covers the classes of non-classical CAIs and the recent advances in the development of isoform-specific inhibitors based on phenols, polyamines, coumarins and their derivatives. PMID:27438828
Fractionalized Z_{2} Classical Heisenberg Spin Liquids.
Rehn, J; Sen, Arnab; Moessner, R
2017-01-27
Quantum spin systems are by now known to exhibit a large number of different classes of spin liquid phases. By contrast, for classical Heisenberg models, only one kind of fractionalized spin liquid phase, the so-called Coulomb or U(1) spin liquid, has until recently been identified: This exhibits algebraic spin correlations and impurity moments, "orphan spins," whose size is a fraction of that of the underlying microscopic degrees of freedom. Here, we present two Heisenberg models exhibiting fractionalization in combination with exponentially decaying correlations. These can be thought of as a classical continuous spin version of a Z_{2} spin liquid. Our work suggests a systematic search and classification of classical spin liquids as a worthwhile endeavor.
Classical Ising model test for quantum circuits
NASA Astrophysics Data System (ADS)
Geraci, Joseph; Lidar, Daniel A.
2010-07-01
We exploit a recently constructed mapping between quantum circuits and graphs in order to prove that circuits corresponding to certain planar graphs can be efficiently simulated classically. The proof uses an expression for the Ising model partition function in terms of quadratically signed weight enumerators (QWGTs), which are polynomials that arise naturally in an expansion of quantum circuits in terms of rotations involving Pauli matrices. We combine this expression with a known efficient classical algorithm for the Ising partition function of any planar graph in the absence of an external magnetic field, and the Robertson-Seymour theorem from graph theory. We give as an example a set of quantum circuits with a small number of non-nearest-neighbor gates which admit an efficient classical simulation.
Quantum and classical optics-emerging links
NASA Astrophysics Data System (ADS)
Eberly, J. H.; Qian, Xiao-Feng; Qasimi, Asma Al; Ali, Hazrat; Alonso, M. A.; Gutiérrez-Cuevas, R.; Little, Bethany J.; Howell, John C.; Malhotra, Tanya; Vamivakas, A. N.
2016-06-01
Quantum optics and classical optics are linked in ways that are becoming apparent as a result of numerous recent detailed examinations of the relationships that elementary notions of optics have with each other. These elementary notions include interference, polarization, coherence, complementarity and entanglement. All of them are present in both quantum and classical optics. They have historic origins, and at least partly for this reason not all of them have quantitative definitions that are universally accepted. This makes further investigation into their engagement in optics very desirable. We pay particular attention to effects that arise from the mere co-existence of separately identifiable and readily available vector spaces. Exploitation of these vector-space relationships are shown to have unfamiliar theoretical implications and new options for observation. It is our goal to bring emerging quantum-classical links into wider view and to indicate directions in which forthcoming and future work will promote discussion and lead to unified understanding.
Voice disorders in children with classic galactosemia.
Potter, Nancy L
2011-04-01
Children with classic galactosemia are at risk for motor speech disorders resulting from disruptions in motor planning and programming (childhood apraxia of speech or CAS) or motor execution (dysarthria). In the present study of 33 children with classic galactosemia, 21% were diagnosed with CAS, 3% with ataxic dysarthria, and 3% with mixed CAS-dysarthria. Voice disorders due to laryngeal insufficiency were common in children with dysarthria and co-occurred with CAS. Most (58%) of the children with classic galactosemia had decreased respiratory-phonatory support for speech, and 33% had disturbed vocal quality that was indicative of cerebellar dysfunction. Three children, two diagnosed with CAS and one not diagnosed with a motor speech disorder, had vocal tremors. Treatment of voice dysfunction in neurogenic speech disorders is discussed.
Modeling Classical Heat Conduction in FLAG
Ramsey, Scott D.; Hendon, Raymond Cori
2015-01-12
The Los Alamos National Laboratory FLAG code contains both electron and ion heat conduction modules; these have been constructed to be directly relevant to user application problems. However, formal code verification of these modules requires quantitative comparison to exact solutions of the underlying mathematical models. A wide variety of exact solutions to the classical heat conduction equation are available for this purpose. This report summarizes efforts involving the representation of the classical heat conduction equation as following from the large electron-ion coupling limit of the electron and ion 3T temperature equations, subject to electron and ion conduction processes. In FLAG, this limiting behavior is quantitatively verified using a simple exact solution of the classical heat conduction equation. For this test problem, both heat conduction modules produce nearly identical spatial electron and ion temperature profiles that converge at slightly less than 2nd order to the corresponding exact solution.
Observable signatures of a classical transition
Johnson, Matthew C.; Lin, Wei E-mail: lewisweilin@gmail.com
2016-03-01
Eternal inflation arising from a potential landscape predicts that our universe is one realization of many possible cosmological histories. One way to access different cosmological histories is via the nucleation of bubble universes from a metastable false vacuum. Another way to sample different cosmological histories is via classical transitions, the creation of pocket universes through the collision between bubbles. Using relativistic numerical simulations, we examine the possibility of observationally determining if our observable universe resulted from a classical transition. We find that classical transitions produce spatially infinite, approximately open Friedman-Robertson-Walker universes. The leading set of observables in the aftermath of a classical transition are negative spatial curvature and a contribution to the Cosmic Microwave Background temperature quadrupole. The level of curvature and magnitude of the quadrupole are dependent on the position of the observer, and we determine the possible range of observables for two classes of single-scalar field models. For the first class, where the inflationary phase has a lower energy than the vacuum preceding the classical transition, the magnitude of the observed quadrupole generally falls to zero with distance from the collision while the spatial curvature grows to a constant. For the second class, where the inflationary phase has a higher energy than the vacuum preceding the classical transition, the magnitude of the observed quadrupole generically falls to zero with distance from the collision while the spatial curvature grows without bound. We find that the magnitude of the quadrupole and curvature grow with increasing centre of mass energy of the collision, and explore variations of the parameters in the scalar field lagrangian.
Classical ultra-relativistic scattering in ADD
NASA Astrophysics Data System (ADS)
Gal'tsov, Dmitry V.; Kofinas, Georgios; Spirin, Pavel; Tomaras, Theodore N.
2009-05-01
The classical differential cross-section is calculated for high-energy small-angle gravitational scattering in the factorizable model with toroidal extra dimensions. The three main features of the classical computation are: (a) It involves summation over the infinite Kaluza-Klein towers but, contrary to the Born amplitude, it is finite with no need of an ultraviolet cutoff. (b) It is shown to correspond to the non-perturbative saddle-point approximation of the eikonal amplitude, obtained by the summation of an infinite number of ladder graphs of the quantum theory. (c) In the absence of extra dimensions it reproduces all previously known results.
Classical noise, quantum noise and secure communication
NASA Astrophysics Data System (ADS)
Tannous, C.; Langlois, J.
2016-01-01
Secure communication based on message encryption might be performed by combining the message with controlled noise (called pseudo-noise) as performed in spread-spectrum communication used presently in Wi-Fi and smartphone telecommunication systems. Quantum communication based on entanglement is another route for securing communications as demonstrated by several important experiments described in this work. The central role played by the photon in unifying the description of classical and quantum noise as major ingredients of secure communication systems is highlighted and described on the basis of the classical and quantum fluctuation dissipation theorems.
Classical swine fever in China: a minireview.
Luo, Yuzi; Li, Su; Sun, Yuan; Qiu, Hua-Ji
2014-08-06
Classical swine fever (CSF), caused by Classical swine fever virus (CSFV), is an OIE-listed, highly contagious, often fatal disease of swine worldwide. Currently, the disease is controlled by prophylactic vaccination in China and many other countries using the modified live vaccines derived from C-strain, which was developed in China in the mid-1950s. This minireview summarizes the epidemiology, diagnostic assays, control and challenges of CSF in China. Though CSF is essentially under control, complete eradication of CSF in China remains a challenging task and needs long-term, joint efforts of stakeholders.
The classic. Review article: Traffic accidents. 1966.
Tscherne, H
2013-09-01
This Classic Article is a translation of the original work by Prof. Harald Tscherne, Der Straßenunfall [Traffic Accidents]. An accompanying biographical sketch of Prof. Tscherne is available at DOI 10.1007/s11999-013-3011-x . An online version of the original German article is available as supplemental material. The Classic Article is reproduced with permission from Brüder Hollinek & Co. GesmbH, Purkersdorf, Austria. The original article was published in Wien Med Wochenschr. 1966;116:105-108. (Translated by Dr. Roman Pfeifer.).
Are Volume Plasmons Excitable by Classical Light?
NASA Astrophysics Data System (ADS)
Höflich, Katja; Gösele, Ulrich; Christiansen, Silke
2009-08-01
Volume plasmons are collective eigenmodes of the free-electron gas inside a metal. Because of their longitudinal character and the transversal nature of light, the photoexcitation of volume plasmons is forbidden in classical electrodynamics. Nevertheless, we show their existence for metallic nanoshells using analytical solutions of the classical scattering problem. Solely for the case of a vanishing real part of the shell permittivity, a local maximum at the natural plasma frequency appears in the extinction spectra. For explaining our observations, we suggest a simple physical picture which is supported by examples on silver and gold shells.
Thermodynamic integration from classical to quantum mechanics.
Habershon, Scott; Manolopoulos, David E
2011-12-14
We present a new method for calculating quantum mechanical corrections to classical free energies, based on thermodynamic integration from classical to quantum mechanics. In contrast to previous methods, our method is numerically stable even in the presence of strong quantum delocalization. We first illustrate the method and its relationship to a well-established method with an analysis of a one-dimensional harmonic oscillator. We then show that our method can be used to calculate the quantum mechanical contributions to the free energies of ice and water for a flexible water model, a problem for which the established method is unstable.
Force fields for classical molecular dynamics.
Monticelli, Luca; Tieleman, D Peter
2013-01-01
In this chapter we review the basic features and the principles underlying molecular mechanics force fields commonly used in molecular modeling of biological macromolecules. We start by summarizing the historical background and then describe classical pairwise additive potential energy functions. We introduce the problem of the calculation of nonbonded interactions, of particular importance for charged macromolecules. Different parameterization philosophies are then presented, followed by a section on force field validation. We conclude with a brief overview on future perspectives for the development of classical force fields.
Manikandan, Paranjothy; Hase, William L
2012-05-14
Previous studies have shown that classical trajectory simulations often give accurate results for short-time intramolecular and unimolecular dynamics, particularly for initial non-random energy distributions. To obtain such agreement between experiment and simulation, the appropriate distributions must be sampled to choose initial coordinates and momenta for the ensemble of trajectories. If a molecule's classical phase space is sampled randomly, its initial decomposition will give the classical anharmonic microcanonical (RRKM) unimolecular rate constant for its decomposition. For the work presented here, classical trajectory simulations of the unimolecular decomposition of quantum and classical microcanonical ensembles, at the same fixed total energy, are compared. In contrast to the classical microcanonical ensemble, the quantum microcanonical ensemble does not sample the phase space randomly. The simulations were performed for CH(4), C(2)H(5), and Cl(-)---CH(3)Br using both analytic potential energy surfaces and direct dynamics methods. Previous studies identified intrinsic RRKM dynamics for CH(4) and C(2)H(5), but intrinsic non-RRKM dynamics for Cl(-)---CH(3)Br. Rate constants calculated from trajectories obtained by the time propagation of the classical and quantum microcanonical ensembles are compared with the corresponding harmonic RRKM estimates to obtain anharmonic corrections to the RRKM rate constants. The relevance and accuracy of the classical trajectory simulation of the quantum microcanonical ensemble, for obtaining the quantum anharmonic RRKM rate constant, is discussed.
Trajectory description of the quantum–classical transition for wave packet interference
Chou, Chia-Chun
2016-08-15
The quantum–classical transition for wave packet interference is investigated using a hydrodynamic description. A nonlinear quantum–classical transition equation is obtained by introducing a degree of quantumness ranging from zero to one into the classical time-dependent Schrödinger equation. This equation provides a continuous description for the transition process of physical systems from purely quantum to purely classical regimes. In this study, the transition trajectory formalism is developed to provide a hydrodynamic description for the quantum–classical transition. The flow momentum of transition trajectories is defined by the gradient of the action function in the transition wave function and these trajectories follow the main features of the evolving probability density. Then, the transition trajectory formalism is employed to analyze the quantum–classical transition of wave packet interference. For the collision-like wave packet interference where the propagation velocity is faster than the spreading speed of the wave packet, the interference process remains collision-like for all the degree of quantumness. However, the interference features demonstrated by transition trajectories gradually disappear when the degree of quantumness approaches zero. For the diffraction-like wave packet interference, the interference process changes continuously from a diffraction-like to collision-like case when the degree of quantumness gradually decreases. This study provides an insightful trajectory interpretation for the quantum–classical transition of wave packet interference.
Trajectory description of the quantum-classical transition for wave packet interference
NASA Astrophysics Data System (ADS)
Chou, Chia-Chun
2016-08-01
The quantum-classical transition for wave packet interference is investigated using a hydrodynamic description. A nonlinear quantum-classical transition equation is obtained by introducing a degree of quantumness ranging from zero to one into the classical time-dependent Schrödinger equation. This equation provides a continuous description for the transition process of physical systems from purely quantum to purely classical regimes. In this study, the transition trajectory formalism is developed to provide a hydrodynamic description for the quantum-classical transition. The flow momentum of transition trajectories is defined by the gradient of the action function in the transition wave function and these trajectories follow the main features of the evolving probability density. Then, the transition trajectory formalism is employed to analyze the quantum-classical transition of wave packet interference. For the collision-like wave packet interference where the propagation velocity is faster than the spreading speed of the wave packet, the interference process remains collision-like for all the degree of quantumness. However, the interference features demonstrated by transition trajectories gradually disappear when the degree of quantumness approaches zero. For the diffraction-like wave packet interference, the interference process changes continuously from a diffraction-like to collision-like case when the degree of quantumness gradually decreases. This study provides an insightful trajectory interpretation for the quantum-classical transition of wave packet interference.
Unraveling Quantum Annealers using Classical Hardness
NASA Astrophysics Data System (ADS)
Martin-Mayor, Victor; Hen, Itay
2015-10-01
Recent advances in quantum technology have led to the development and manufacturing of experimental programmable quantum annealing optimizers that contain hundreds of quantum bits. These optimizers, commonly referred to as ‘D-Wave’ chips, promise to solve practical optimization problems potentially faster than conventional ‘classical’ computers. Attempts to quantify the quantum nature of these chips have been met with both excitement and skepticism but have also brought up numerous fundamental questions pertaining to the distinguishability of experimental quantum annealers from their classical thermal counterparts. Inspired by recent results in spin-glass theory that recognize ‘temperature chaos’ as the underlying mechanism responsible for the computational intractability of hard optimization problems, we devise a general method to quantify the performance of quantum annealers on optimization problems suffering from varying degrees of temperature chaos: A superior performance of quantum annealers over classical algorithms on these may allude to the role that quantum effects play in providing speedup. We utilize our method to experimentally study the D-Wave Two chip on different temperature-chaotic problems and find, surprisingly, that its performance scales unfavorably as compared to several analogous classical algorithms. We detect, quantify and discuss several purely classical effects that possibly mask the quantum behavior of the chip.
Can Communicative Principles Enhance Classical Language Acquisition?
ERIC Educational Resources Information Center
Overland, Paul; Fields, Lee; Noonan, Jennifer
2011-01-01
Is it feasible for nonfluent instructors to teach Biblical Hebrew by communicative principles? If it is feasible, will communicative instruction enhance postsecondary learning of a classical language? To begin answering these questions, two consultants representing second language acquisition (SLA) and technology-assisted language learning led 8…
Using CAS to Solve Classical Mathematics Problems
ERIC Educational Resources Information Center
Burke, Maurice J.; Burroughs, Elizabeth A.
2009-01-01
Historically, calculus has displaced many algebraic methods for solving classical problems. This article illustrates an algebraic method for finding the zeros of polynomial functions that is closely related to Newton's method (devised in 1669, published in 1711), which is encountered in calculus. By exploring this problem, precalculus students…
Comparison of Classical and Quantum Mechanical Uncertainties.
ERIC Educational Resources Information Center
Peslak, John, Jr.
1979-01-01
Comparisons are made for the particle-in-a-box, the harmonic oscillator, and the one-electron atom. A classical uncertainty principle is derived and compared with its quantum-mechanical counterpart. The results are discussed in terms of the statistical interpretation of the uncertainty principle. (Author/BB)
Entanglement in Quantum-Classical Hybrid
NASA Technical Reports Server (NTRS)
Zak, Michail
2011-01-01
It is noted that the phenomenon of entanglement is not a prerogative of quantum systems, but also occurs in other, non-classical systems such as quantum-classical hybrids, and covers the concept of entanglement as a special type of global constraint imposed upon a broad class of dynamical systems. Application of hybrid systems for physics of life, as well as for quantum-inspired computing, has been outlined. In representing the Schroedinger equation in the Madelung form, there is feedback from the Liouville equation to the Hamilton-Jacobi equation in the form of the quantum potential. Preserving the same topology, the innovators replaced the quantum potential with other types of feedback, and investigated the property of these hybrid systems. A function of probability density has been introduced. Non-locality associated with a global geometrical constraint that leads to an entanglement effect was demonstrated. Despite such a quantum like characteristic, the hybrid can be of classical scale and all the measurements can be performed classically. This new emergence of entanglement sheds light on the concept of non-locality in physics.
Selected topics from classical bacterial genetics.
Raleigh, Elisabeth A; Elbing, Karen; Brent, Roger
2002-08-01
Current cloning technology exploits many facts learned from classical bacterial genetics. This unit covers those that are critical to understanding the techniques described in this book. Topics include antibiotics, the LAC operon, the F factor, nonsense suppressors, genetic markers, genotype and phenotype, DNA restriction, modification and methylation and recombination.
Unraveling a classical mechanics brain twister
NASA Astrophysics Data System (ADS)
Paris, Norman; Broide, Michael L.
2011-12-01
We present a comprehensive analysis of an intriguing classical mechanics problem involving the coupled motion of two blocks. The problem illustrates fundamental physics concepts and theoretical techniques. We solve the equations of motion numerically and gain insight into common misconceptions about this system. The problem provides rich opportunities for student investigations using analytical and numerical methods.
The classical pion field in a nucleus
NASA Astrophysics Data System (ADS)
Ripka, Georges
2008-12-01
A self-consistent symmetry arises when the nucleon angular momentum j and the isospin t are coupled to a grand spin G. Closed G shells become sources of a classical pion field with a hedgehog shape. Although the amplitude of the pion field, as measured by the chiral angle, is small, it is found to perturb significantly the energies of the nucleon orbits.
Concerning gauge field fluctuations around classical configurations
Dietrich, Dennis D.
2009-05-15
We treat the fluctuations of non-Abelian gauge fields around a classical configuration by means of a transformation from the Yang-Mills gauge field to a homogeneously transforming field variable. We use the formalism to compute the effective action induced by these fluctuations in a static background without Wu-Yang ambiguity.
Essays on Classical Rhetoric and Modern Discourse.
ERIC Educational Resources Information Center
Connors, Robert J., Ed.; And Others
Noting the rediscovery by composition scholars of the tradition of classical rhetoric, this collection of essays explores the resurgence in the teaching of written discourse in college English departments. The 18 articles and their authors are as follows: (1) "The Revival of Rhetoric in America," by Robert Connors, Lisa Ede, and Andrea…
Medical and rehabilitation issues in classical ballet.
Stretanski, Michael F; Weber, G J
2002-05-01
Classical ballet is a demanding professional occupation, with participants who are often underserved in terms of accurate diagnosis and appropriate comprehensive medical care. The view that follows is designed to be as global and insightful as published to date. Specific rehabilitation considerations, dance mechanics, idiosyncratic differential diagnosis, and personality and equipment issues are discussed, and a rational view of dogma is presented.
The Oxford Treasury of Classic Poems.
ERIC Educational Resources Information Center
Harrison, Michael, Ed.; Stuart-Clark, Christopher, Ed.
This book contains over 90 classic poems for children. The collection of poems includes nonsense verse by Lear and Carroll, story poems by Tennyson and Keats, and humorous poems by Belloc and Betjeman. The collection also includes poems by modern poets, such as Charles Causley, Ted Hughes, John Agard, Roger McGough, and Stevie Smith. The…
Foreign Language, the Classics, and College Admissions.
ERIC Educational Resources Information Center
LaFleur, Richard A.
1993-01-01
This article reports the results of a survey, funded by the American Classical League (ACL) and conducted during 1990-91, that assessed attitudes toward high school foreign-language study, in particular the study of Latin and Greek, in the college admissions process. (21 references) (VWL)
Gender and the Classics Curriculum: A Survey
ERIC Educational Resources Information Center
Blundell, Sue
2009-01-01
A survey was carried out in 2006 of all the UK universities where Classics and Ancient History degrees are taught at undergraduate level. The results reveal that nearly half of these courses include at least one dedicated gender module, and that the great majority also have gender embedded in the content of modules dealing with other topics.…
Classical Pragmatism on Mind and Rationality
ERIC Educational Resources Information Center
Maattanen, Pentti
2005-01-01
One of the major changes in twentieth century philosophy was the so-called linguistic turn, in which natural and formal languages became central subjects of study. This meant that theories of meaning became mostly about linguistic meaning, thinking was now analyzed in terms of symbol manipulation, and rules of classical logic formed the nucleus of…
Classic hallucinogens in the treatment of addictions.
Bogenschutz, Michael P; Johnson, Matthew W
2016-01-04
Addictive disorders are very common and have devastating individual and social consequences. Currently available treatment is moderately effective at best. After many years of neglect, there is renewed interest in potential clinical uses for classic hallucinogens in the treatment of addictions and other behavioral health conditions. In this paper we provide a comprehensive review of both historical and recent clinical research on the use of classic hallucinogens in the treatment of addiction, selectively review other relevant research concerning hallucinogens, and suggest directions for future research. Clinical trial data are very limited except for the use of LSD in the treatment of alcoholism, where a meta-analysis of controlled trials has demonstrated a consistent and clinically significant beneficial effect of high-dose LSD. Recent pilot studies of psilocybin-assisted treatment of nicotine and alcohol dependence had strikingly positive outcomes, but controlled trials will be necessary to evaluate the efficacy of these treatments. Although plausible biological mechanisms have been proposed, currently the strongest evidence is for the role of mystical or other meaningful experiences as mediators of therapeutic effects. Classic hallucinogens have an excellent record of safety in the context of clinical research. Given our limited understanding of the clinically relevant effects of classic hallucinogens, there is a wealth of opportunities for research that could contribute important new knowledge and potentially lead to valuable new treatments for addiction.
Metal Ion Modeling Using Classical Mechanics.
Li, Pengfei; Merz, Kenneth M
2017-02-08
Metal ions play significant roles in numerous fields including chemistry, geochemistry, biochemistry, and materials science. With computational tools increasingly becoming important in chemical research, methods have emerged to effectively face the challenge of modeling metal ions in the gas, aqueous, and solid phases. Herein, we review both quantum and classical modeling strategies for metal ion-containing systems that have been developed over the past few decades. This Review focuses on classical metal ion modeling based on unpolarized models (including the nonbonded, bonded, cationic dummy atom, and combined models), polarizable models (e.g., the fluctuating charge, Drude oscillator, and the induced dipole models), the angular overlap model, and valence bond-based models. Quantum mechanical studies of metal ion-containing systems at the semiempirical, ab initio, and density functional levels of theory are reviewed as well with a particular focus on how these methods inform classical modeling efforts. Finally, conclusions and future prospects and directions are offered that will further enhance the classical modeling of metal ion-containing systems.
The Strange World of Classical Physics
ERIC Educational Resources Information Center
Green, David
2010-01-01
We have heard many times that the commonsense world of classical physics was shattered by Einstein's revelation of the laws of relativity. This is certainly true; the shift from our everyday notions of time and space to those revealed by relativity is one of the greatest stretches the mind can make. What is seldom appreciated is that the laws of…
Metal Ion Modeling Using Classical Mechanics
2017-01-01
Metal ions play significant roles in numerous fields including chemistry, geochemistry, biochemistry, and materials science. With computational tools increasingly becoming important in chemical research, methods have emerged to effectively face the challenge of modeling metal ions in the gas, aqueous, and solid phases. Herein, we review both quantum and classical modeling strategies for metal ion-containing systems that have been developed over the past few decades. This Review focuses on classical metal ion modeling based on unpolarized models (including the nonbonded, bonded, cationic dummy atom, and combined models), polarizable models (e.g., the fluctuating charge, Drude oscillator, and the induced dipole models), the angular overlap model, and valence bond-based models. Quantum mechanical studies of metal ion-containing systems at the semiempirical, ab initio, and density functional levels of theory are reviewed as well with a particular focus on how these methods inform classical modeling efforts. Finally, conclusions and future prospects and directions are offered that will further enhance the classical modeling of metal ion-containing systems. PMID:28045509
On the emergence of classical gravity
NASA Astrophysics Data System (ADS)
Larjo, Klaus
In this thesis I will discuss how certain black holes arise as an effective, thermodynamical description from non-singular microstates in string theory. This provides a possible solution to the information paradox, and strengthens the case for treating black holes as thermodynamical objects. I will characterize the data defining a microstate of a black hole in several settings, and demonstrate that most of the data is unmeasurable for a classical observer. I will further show that the data that is measurable is universal for nearly all microstates, making it impossible for a classical observer to distinguish between microstates, thus giving rise to an effective statistical description for the black hole. In the first half of the thesis I will work with two specific systems: the half-BPS sector of [Special characters omitted.] = 4 super Yang-Mills the and the conformal field theory corresponding to the D1/D5 system; in both cases the high degree of symmetry present provides great control over potentially intractable computations. For these systems, I will further specify the conditions a quantum mechanical microstate must satisfy in order to have a classical description in terms of a unique metric, and define a 'metric operator' whose eigenstates correspond to classical geometries. In the second half of the thesis I will consider a much broader setting, general [Special characters omitted.] = I superconformal quiver gauge the= ories and their dual gravity theories, and demonstrate that a similar effective description arises also in this setting.
Maxwell and the classical wave particle dualism.
Mendonça, J T
2008-05-28
Maxwell's equations are one of the greatest theoretical achievements in physics of all times. They have survived three successive theoretical revolutions, associated with the advent of relativity, quantum mechanics and modern quantum field theory. In particular, they provide the theoretical framework for the understanding of the classical wave particle dualism.
Louis Guttman's Contributions to Classical Test Theory
ERIC Educational Resources Information Center
Zimmerman, Donald W.; Williams, Richard H.; Zumbo, Bruno D.; Ross, Donald
2005-01-01
This article focuses on Louis Guttman's contributions to the classical theory of educational and psychological tests, one of the lesser known of his many contributions to quantitative methods in the social sciences. Guttman's work in this field provided a rigorous mathematical basis for ideas that, for many decades after Spearman's initial work,…
Classic Readers Theatre for Young Adults.
ERIC Educational Resources Information Center
Barchers, Suzanne I.; Kroll, Jennifer L.
This book presents 16 original scripts that have been adapted from classic works of literature for use for readers theatre with young adults and ESL (English as a Second Language) students. Adaptations of the following works are included: "Little Women" (Louisa May Alcott); episodes from "Don Quixote" (Miguel de Cervantes; "The Necklace" (Guy de…
Unified classical path theories of pressure broadening.
NASA Technical Reports Server (NTRS)
Bottcher, C.
1971-01-01
Derivation of a unified classical path theory of pressure broadening, using only elementary concepts. It is shown that the theory of Smith, Cooper and Vidal (1969) is only correct at all frequencies to first order in the number density of perturbers.
Unraveling Quantum Annealers using Classical Hardness
Martin-Mayor, Victor; Hen, Itay
2015-01-01
Recent advances in quantum technology have led to the development and manufacturing of experimental programmable quantum annealing optimizers that contain hundreds of quantum bits. These optimizers, commonly referred to as ‘D-Wave’ chips, promise to solve practical optimization problems potentially faster than conventional ‘classical’ computers. Attempts to quantify the quantum nature of these chips have been met with both excitement and skepticism but have also brought up numerous fundamental questions pertaining to the distinguishability of experimental quantum annealers from their classical thermal counterparts. Inspired by recent results in spin-glass theory that recognize ‘temperature chaos’ as the underlying mechanism responsible for the computational intractability of hard optimization problems, we devise a general method to quantify the performance of quantum annealers on optimization problems suffering from varying degrees of temperature chaos: A superior performance of quantum annealers over classical algorithms on these may allude to the role that quantum effects play in providing speedup. We utilize our method to experimentally study the D-Wave Two chip on different temperature-chaotic problems and find, surprisingly, that its performance scales unfavorably as compared to several analogous classical algorithms. We detect, quantify and discuss several purely classical effects that possibly mask the quantum behavior of the chip. PMID:26483257
The Classical Version of Stokes' Theorem Revisited
ERIC Educational Resources Information Center
Markvorsen, Steen
2008-01-01
Using only fairly simple and elementary considerations--essentially from first year undergraduate mathematics--we show how the classical Stokes' theorem for any given surface and vector field in R[superscript 3] follows from an application of Gauss' divergence theorem to a suitable modification of the vector field in a tubular shell around the…
Studying the Leaders of Classical Antiquity.
ERIC Educational Resources Information Center
Moritz, Helen E.
This paper describes a graduate seminar for educational administrators, using works of ancient Greek and Roman literature as bases for the consideration of organization and leadership problems identified in theoretical literature. The seminar was team taught by professors from the Departments of Educational Administration and Classics at the…
Classical enhancement of quantum vacuum fluctuations
NASA Astrophysics Data System (ADS)
De Lorenci, V. A.; Ford, L. H.
2017-01-01
We propose a mechanism for the enhancement of vacuum fluctuations by means of a classical field. The basic idea is that if an observable quantity depends quadratically upon a quantum field, such as the electric field, then the application of a classical field produces a cross term between the classical and quantum fields. This cross term may be significantly larger than the purely quantum part, but also undergoes fluctuations driven by the quantum field. We illustrate this effect in a model for light-cone fluctuations involving pulses in a nonlinear dielectric. Vacuum electric field fluctuations produce fluctuations in the speed of a probe pulse, and form an analog model for quantum gravity effects. If the material has a nonzero third-order susceptibility, then the fractional light speed fluctuations are proportional to the square of the fluctuating electric field. Hence the application of a classical electric field can enhance the speed fluctuations. We give an example where this enhancement can be an increase of 1 order of magnitude, increasing the possibility of observing the effect.
Acceleration of Classical Mechanics by Phase Space Constraints.
Martínez-Núñez, Emilio; Shalashilin, Dmitrii V
2006-07-01
In this article phase space constrained classical mechanics (PSCCM), a version of accelerated dynamics, is suggested to speed up classical trajectory simulations of slow chemical processes. The approach is based on introducing constraints which lock trajectories in the region of the phase space close to the dividing surface, which separates reactants and products. This results in substantial (up to more than 2 orders of magnitude) speeding up of the trajectory simulation. Actual microcanonical rates are calculated by introducing a correction factor equal to the fraction of the phase volume which is allowed by the constraints. The constraints can be more complex than previously used boosting potentials. The approach has its origin in Intramolecular Dynamics Diffusion Theory, which shows that the majority of nonstatistical effects are localized near the transition state. An excellent agreement with standard trajectory simulation at high energies and Monte Carlo Transition State Theory at low energies is demonstrated for the unimolecular dissociation of methyl nitrite, proving that PSCCM works both in statistical and nonstatistical regimes.
Classical and quantum particle dynamics in univariate background fields
NASA Astrophysics Data System (ADS)
Heinzl, T.; Ilderton, A.; King, B.
2016-09-01
We investigate deviations from the plane wave model in the interaction of charged particles with strong electromagnetic fields. A general result is that integrability of the dynamics is lost when going from lightlike to timelike or spacelike field dependence. For a special scenario in the classical regime we show how the radiation spectrum in the spacelike (undulator) case becomes well-approximated by the plane wave model in the high-energy limit, despite the two systems being Lorentz inequivalent. In the quantum problem, there is no analogue of the WKB-exact Volkov solution. Nevertheless, WKB and uniform-WKB approaches give good approximations in all cases considered. Other approaches that reduce the underlying differential equations from second to first order are found to miss the correct physics for situations corresponding to barrier transmission and wide-angle scattering.
Kinetic Monte Carlo simulation of the classical nucleation process
NASA Astrophysics Data System (ADS)
Filipponi, A.; Giammatteo, P.
2016-12-01
We implemented a kinetic Monte Carlo computer simulation of the nucleation process in the framework of the coarse grained scenario of the Classical Nucleation Theory (CNT). The computational approach is efficient for a wide range of temperatures and sample sizes and provides a reliable simulation of the stochastic process. The results for the nucleation rate are in agreement with the CNT predictions based on the stationary solution of the set of differential equations for the continuous variables representing the average population distribution of nuclei size. Time dependent nucleation behavior can also be simulated with results in agreement with previous approaches. The method, here established for the case in which the excess free-energy of a crystalline nucleus is a smooth-function of the size, can be particularly useful when more complex descriptions are required.
Stulpe, Werner
2014-01-15
The concept of an injective affine embedding of the quantum states into a set of classical states, i.e., into the set of the probability measures on some measurable space, as well as its relation to statistically complete observables is revisited, and its limitation in view of a classical reformulation of the statistical scheme of quantum mechanics is discussed. In particular, on the basis of a theorem concerning a non-denseness property of a set of coexistent effects, it is shown that an injective classical embedding of the quantum states cannot be supplemented by an at least approximate classical description of the quantum mechanical effects. As an alternative approach, the concept of quasi-probability representations of quantum mechanics is considered.
Report of the Colloquium on the Classics in Education, 1965.
ERIC Educational Resources Information Center
Else, Gerald F., Ed.
This is the report of an international meeting on the Classics, conducted August 1965 in London, England. Resolutions adopted by the Colloquium, minutes of group sessions, papers, and national reports on the state of classical education are presented. Group sessions discuss the teaching of classical languages, classical literatures, and ancient…
Whitley, Heather D.; Scullard, Christian R.; Benedict, Lorin X.; ...
2014-12-04
Here, we present a discussion of kinetic theory treatments of linear electrical and thermal transport in hydrogen plasmas, for a regime of interest to inertial confinement fusion applications. In order to assess the accuracy of one of the more involved of these approaches, classical Lenard-Balescu theory, we perform classical molecular dynamics simulations of hydrogen plasmas using 2-body quantum statistical potentials and compute both electrical and thermal conductivity from out particle trajectories using the Kubo approach. Our classical Lenard-Balescu results employing the identical statistical potentials agree well with the simulations.
Cholera outbreaks in the classical biotype era.
Siddique, A K; Cash, Richard
2014-01-01
In the Indian subcontinent description of a disease resembling cholera has been mentioned in Sushruta Samita, estimated to have been written between ~400 and 500 BC. It is however not clear whether the disease known today as cholera caused by Vibrio cholerae Vibrio cholerae O1 is the evolutionary progression of the ancient disease. The modern history of cholera began in 1817 when an explosive epidemic broke out in the Ganges River Delta region of Bengal. This was the first of the seven recorded cholera pandemics cholera pandemics that affected nearly the entire world and caused hundreds of thousands of deaths. The bacterium responsible for this human disease was first recognised during the fifth pandemic and was named V. cholerae which was grouped as O1, and was further differentiated into Classical and El Tor biotypes. It is now known that the fifth and the sixth pandemics were caused by the V. cholerae O1 of the Classical biotype Classical biotype and the seventh by the El Tor biotype El Tor biotype . The El Tor biotype of V. cholerae, which originated in Indonesia Indonesia and shortly thereafter began to spread in the early 1960s. Within the span of 50 years the El Tor biotype had invaded nearly the entire world, completely displacing the Classical biotype from all the countries except Bangladesh. What prompted the earlier pandemics to begin is not clearly understood, nor do we know how and why they ended. The success of the seventh pandemic clone over the pre-existing sixth pandemic strain remains largely an unsolved mystery. Why classical biotype eventually disappeared from the world remains to be explained. For nearly three decades (1963-1991) during the Seventh cholera pandemic seventh pandemic, cholera in Bangladesh has recorded a unique history of co-existence of Classical and El Tor biotypes of V. cholerae O1 as epidemic and endemic strain. This long co-existence has provided us with great opportunity to improve our understanding of the disease itself
Classical Photogrammetry and Uav - Selected Ascpects
NASA Astrophysics Data System (ADS)
Mikrut, S.
2016-06-01
The UAV technology seems to be highly future-oriented due to its low costs as compared to traditional aerial images taken from classical photogrammetry aircrafts. The AGH University of Science and Technology in Cracow - Department of Geoinformation, Photogrammetry and Environmental Remote Sensing focuses mainly on geometry and radiometry of recorded images. Various scientific research centres all over the world have been conducting the relevant research for years. The paper presents selected aspects of processing digital images made with the UAV technology. It provides on a practical example a comparison between a digital image taken from an airborne (classical) height, and the one made from an UAV level. In his research the author of the paper is trying to find an answer to the question: to what extent does the UAV technology diverge today from classical photogrammetry, and what are the advantages and disadvantages of both methods? The flight plan was made over the Tokarnia Village Museum (more than 0.5 km2) for two separate flights: the first was made by an UAV - System FT-03A built by FlyTech Solution Ltd. The second was made with the use of a classical photogrammetric Cesna aircraft furnished with an airborne photogrammetric camera (Ultra Cam Eagle). Both sets of photographs were taken with pixel size of about 3 cm, in order to have reliable data allowing for both systems to be compared. The project has made aerotriangulation independently for the two flights. The DTM was generated automatically, and the last step was the generation of an orthophoto. The geometry of images was checked under the process of aerotriangulation. To compare the accuracy of these two flights, control and check points were used. RMSE were calculated. The radiometry was checked by a visual method and using the author's own algorithm for feature extraction (to define edges with subpixel accuracy). After initial pre-processing of data, the images were put together, and shown side by side
Classical morphology of plants as an elementary instance of classical invariant theory.
Mavrodiev, Evgeny V
2009-09-11
It has long been known that structural chemistry shows an intriguing correspondence with Classical Invariant Theory (CIT). Under this view, an algebraic binary form of the degree n corresponds to a chemical atom with valence n and each physical molecule or ion has an invariant-theoretic counterpart. This theory was developed using the Aronhold symbolical approach and the symbolical processes of convolution/transvection in CIT was characterized as a potential "accurate morphological method". However, CIT has not been applied to the formal morphology of living organisms. Based on the morphological interpretation of binary form, as well as the process of convolution/transvection, the First and Second Fundamental Theorems of CIT and the Nullforms of CIT, we show how CIT can be applied to the structure of plants, especially when conceptualized as a series of plant metamers (phytomers). We also show that the weight of the covariant/invariant that describes a morphological structure is a criterion of simplicity and, therefore, we argue that this allows us to formulate a parsimonious method of formal morphology. We demonstrate that the "theory of axilar bud" is the simplest treatment of the grass seedling/embryo. Our interpretations also represent Troll's bauplan of the angiosperms, the principle of variable proportions, morphological misfits, the basic types of stem segmentation, and Goethe's principle of metamorphosis in terms of CIT. Binary forms of different degrees might describe any repeated module of plant organisms. As bacteria, invertebrates, and higher vertebrates are all generally shared a metameric morphology, wider implications of the proposed symmetry between CIT and formal morphology of plants are apparent.
Phase difference enhancement with classical intensity interferometry
NASA Astrophysics Data System (ADS)
Shirai, Tomohiro
2016-12-01
It is demonstrated theoretically and experimentally that, as a novel function of classical intensity interferometry, a phase difference distribution recorded in the form of an interferogram can be enhanced by a factor of 2 on the basis of the classical intensity correlation. Such phase difference enhancement which is also referred to as phase difference amplification is, in general, known to be practically important since it increases sensitivity and accuracy in interferometric measurements. The method proposed in this study prevails over the existing methods in the sense that it can be readily implemented without difficulty in comparison with all other methods so far proposed, although the phase difference enhancement is limited to a factor of 2 in our method and thus so is the improvement of sensitivity and accuracy.
Fast forward to the classical adiabatic invariant
NASA Astrophysics Data System (ADS)
Jarzynski, Christopher; Deffner, Sebastian; Patra, Ayoti; Subaşı, Yiǧit
2017-03-01
We show how the classical action, an adiabatic invariant, can be preserved under nonadiabatic conditions. Specifically, for a time-dependent Hamiltonian H =p2/2 m +U (q ,t ) in one degree of freedom, and for an arbitrary choice of action I0, we construct a so-called fast-forward potential energy function VFF(q ,t ) that, when added to H , guides all trajectories with initial action I0 to end with the same value of action. We use this result to construct a local dynamical invariant J (q ,p ,t ) whose value remains constant along these trajectories. We illustrate our results with numerical simulations. Finally, we sketch how our classical results may be used to design approximate quantum shortcuts to adiabaticity.
Macroscopic quantum mechanics in a classical spacetime.
Yang, Huan; Miao, Haixing; Lee, Da-Shin; Helou, Bassam; Chen, Yanbei
2013-04-26
We apply the many-particle Schrödinger-Newton equation, which describes the coevolution of a many-particle quantum wave function and a classical space-time geometry, to macroscopic mechanical objects. By averaging over motions of the objects' internal degrees of freedom, we obtain an effective Schrödinger-Newton equation for their centers of mass, which can be monitored and manipulated at quantum levels by state-of-the-art optomechanics experiments. For a single macroscopic object moving quantum mechanically within a harmonic potential well, its quantum uncertainty is found to evolve at a frequency different from its classical eigenfrequency-with a difference that depends on the internal structure of the object-and can be observable using current technology. For several objects, the Schrödinger-Newton equation predicts semiclassical motions just like Newtonian physics, yet quantum uncertainty cannot be transferred from one object to another.
Isoperiodic classical systems and their quantum counterparts
NASA Astrophysics Data System (ADS)
Asorey, M.; Cariñena, J. F.; Marmo, G.; Perelomov, A.
2007-06-01
One-dimensional isoperiodic classical systems have been first analyzed by Abel. Abel's characterization can be extended for singular potentials and potentials which are not defined on the whole real line. The standard shear equivalence of isoperiodic potentials can also be extended by using reflection and inversion transformations. We provide a full characterization of isoperiodic rational potentials showing that they are connected by translations, reflections or Joukowski transformations. Upon quantization many of these isoperiodic systems fail to exhibit identical quantum energy spectra. This anomaly occurs at order O( ℏ2) because semiclassical corrections of energy levels of order O( ℏ) are identical for all isoperiodic systems. We analyze families of systems where this quantum anomaly occurs and some special systems where the spectral identity is preserved by quantization. Conversely, we point out the existence of isospectral quantum systems which do not correspond to isoperiodic classical systems.
Classical simulation of quantum fields I
NASA Astrophysics Data System (ADS)
Hirayama, T.; Holdom, B.
2006-10-01
We study classical field theories in a background field configuration where all modes of the theory are excited, matching the zero-point energy spectrum of quantum field theory. Our construction involves elements of a theory of classical electrodynamics by Wheeler-Feynman and the theory of stochastic electrodynamics of Boyer. The nonperturbative effects of interactions in these theories can be very efficiently studied on the lattice. In lambda phi(4) theory in 1 + 1 dimensions, we find results, in particular, for mass renormalization and the critical coupling for symmetry breaking that are in agreement with their quantum counterparts. We then study the perturbative expansion of the n-point Green's functions and find a loop expansion very similar to that of quantum field theory. When compared to the usual Feynman rules, we find some differences associated with particular combinations of internal lines going on-shell simultaneously.
Coherently enhanced measurements in classical mechanics
NASA Astrophysics Data System (ADS)
Braun, Daniel; Popescu, Sandu
2014-08-01
In all quantitative sciences, it is common practice to increase the signal-to-noise ratio of noisy measurements by measuring identically prepared systems N times and averaging the measurement results. This leads to a scaling of the sensitivity as 1/√N, known in quantum measurement theory as the "standard quantum limit" (SQL). It is known that if one puts the N systems into an entangled state, a scaling as 1/N can be achieved, the socalled "Heisenberg limit" (HL), but decoherence problems have so far prevented implementation of such protocols for large N. Here we show that a method of coherent averaging inspired by a recent entanglement-free quantum enhanced measurement protocol is capable of achieving a sensitivity that scales as 1/N in a purely classical setup. This may substantially improve the measurement of very weak interactions in the classical realm, and, in particular, open a novel route to measuring the gravitational constant with enhanced precision.
Hidden invariance of the free classical particle
Garcia, S. )
1994-06-01
A formalism describing the dynamics of classical and quantum systems from a group theoretical point of view is presented. We apply it to the simple example of the classical free particle. The Galileo group [ital G] is the symmetry group of the free equations of motion. Consideration of the free particle Lagrangian semi-invariance under [ital G] leads to a larger symmetry group, which is a central extension of the Galileo group by the real numbers. We study the dynamics associated with this group, and characterize quantities like Noether invariants and evolution equations in terms of group geometric objects. An extension of the Galileo group by [ital U](1) leads to quantum mechanics.
Quantum and classical phases in optomechanics
NASA Astrophysics Data System (ADS)
Armata, Federico; Latmiral, Ludovico; Pikovski, Igor; Vanner, Michael R.; Brukner, Časlav; Kim, M. S.
2016-06-01
The control of quantum systems requires the ability to change and read-out the phase of a system. The noncommutativity of canonical conjugate operators can induce phases on quantum systems, which can be employed for implementing phase gates and for precision measurements. Here we study the phase acquired by a radiation field after its radiation pressure interaction with a mechanical oscillator, and compare the classical and quantum contributions. The classical description can reproduce the nonlinearity induced by the mechanical oscillator and the loss of correlations between mechanics and optical field at certain interaction times. Such features alone are therefore insufficient for probing the quantum nature of the interaction. Our results thus isolate genuine quantum contributions of the optomechanical interaction that could be probed in current experiments.
Classical sequential growth dynamics for causal sets
NASA Astrophysics Data System (ADS)
Rideout, D. P.; Sorkin, R. D.
2000-01-01
Starting from certain causality conditions and a discrete form of general covariance, we derive a very general family of classically stochastic, sequential growth dynamics for causal sets. The resulting theories provide a relatively accessible ``halfway house'' to full quantum gravity that possibly contains the latter's classical limit (general relativity). Because they can be expressed in terms of state models for an assembly of Ising spins residing on the relations of the causal set, these theories also illustrate how nongravitational matter can arise dynamically from the causal set without having to be built in at the fundamental level. Additionally, our results bring into focus some interpretive issues of importance for a causal set dynamics and for quantum gravity more generally.
Quantum-classical path integral. I. Classical memory and weak quantum nonlocality.
Lambert, Roberto; Makri, Nancy
2012-12-14
We consider rigorous path integral descriptions of the dynamics of a quantum system coupled to a polyatomic environment, assuming that the latter is well approximated by classical trajectories. Earlier work has derived semiclassical or purely classical expressions for the influence functional from the environment, which should be sufficiently accurate for many situations, but the evaluation of quantum-(semi)classical path integral (QCPI) expressions has not been practical for large-scale simulation because the interaction with the environment introduces couplings nonlocal in time. In this work, we analyze the nature of the effects on a system from its environment in light of the observation [N. Makri, J. Chem. Phys. 109, 2994 (1998)] that true nonlocality in the path integral is a strictly quantum mechanical phenomenon. If the environment is classical, the path integral becomes local and can be evaluated in a stepwise fashion along classical trajectories of the free solvent. This simple "classical path" limit of QCPI captures fully the decoherence of the system via a classical mechanism. Small corrections to the classical path QCPI approximation may be obtained via an inexpensive random hop QCPI model, which accounts for some "back reaction" effects. Exploiting the finite length of nonlocality, we argue that further inclusion of quantum decoherence is possible via an iterative evaluation of the path integral. Finally, we show that the sum of the quantum amplitude factors with respect to the system paths leads to a smooth integrand as a function of trajectory initial conditions, allowing the use of Monte Carlo methods for the multidimensional phase space integral.
New variables for classical and quantum gravity
NASA Technical Reports Server (NTRS)
Ashtekar, Abhay
1986-01-01
A Hamiltonian formulation of general relativity based on certain spinorial variables is introduced. These variables simplify the constraints of general relativity considerably and enable one to imbed the constraint surface in the phase space of Einstein's theory into that of Yang-Mills theory. The imbedding suggests new ways of attacking a number of problems in both classical and quantum gravity. Some illustrative applications are discussed.
Wei-Norman equations for classical groups
NASA Astrophysics Data System (ADS)
Charzyński, Szymon; Kuś, Marek
2015-08-01
We show that the nonlinear autonomous Wei-Norman equations, expressing the solution of a linear system of non-autonomous equations on a Lie algebra, can be reduced to the hierarchy of matrix Riccati equations in the case of all classical simple Lie algebras. The result generalizes our previous one concerning the complex Lie algebra of the special linear group. We show that it cannot be extended to all simple Lie algebras, in particular to the exceptional G2 algebra.
Maxwellian distribution in non-classical regime
NASA Astrophysics Data System (ADS)
Mohazzabi, Pirooz; L. Helvey, Shannon; McCumber, Jeremy
2002-12-01
A molecular dynamics investigation shows that the assumption of molecular chaos remains valid in the non-classical regime. Consequently, the velocity distribution function of an extremely dense system of spinless particles relaxes into Maxwellian, even in the presence of arbitrary interactions between the particles of the system. Systems with densities exceeding 30 times solid densities are investigated using a soft Lennard-Jones interparticle potential energy function.
INCLINATION MIXING IN THE CLASSICAL KUIPER BELT
Volk, Kathryn; Malhotra, Renu
2011-07-20
We investigate the long-term evolution of the inclinations of the known classical and resonant Kuiper Belt objects (KBOs). This is partially motivated by the observed bimodal inclination distribution and by the putative physical differences between the low- and high-inclination populations. We find that some classical KBOs undergo large changes in inclination over gigayear timescales, which means that a current member of the low-inclination population may have been in the high-inclination population in the past, and vice versa. The dynamical mechanisms responsible for the time variability of inclinations are predominantly distant encounters with Neptune and chaotic diffusion near the boundaries of mean motion resonances. We reassess the correlations between inclination and physical properties including inclination time variability. We find that the size-inclination and color-inclination correlations are less statistically significant than previously reported (mostly due to the increased size of the data set since previous works with some contribution from inclination variability). The time variability of inclinations does not change the previous finding that binary classical KBOs have lower inclinations than non-binary objects. Our study of resonant objects in the classical Kuiper Belt region includes objects in the 3:2, 7:4, 2:1, and eight higher-order mean motion resonances. We find that these objects (some of which were previously classified as non-resonant) undergo larger changes in inclination compared to the non-resonant population, indicating that their current inclinations are not generally representative of their original inclinations. They are also less stable on gigayear timescales.
Classical Analogs of a Diatomic Chain
Gutierrez, L.; Diaz-de-Anda, A.; Mendez-Sanchez, R. A.; Morales, A.; Flores, J.; Monsivais, G.
2010-12-21
Using one dimensional rods with different configurations classical analogs of quantum mechanical systems frequently used in solid state physics can be obtained. Among this analogs we have recently discussed locally periodic rods which lead to band spectra; the effect of a topological defect, and the Wannier Stark ladders. In this paper, we present an elastic analog of the diatomic chain and show how the acoustical and optical bands emerge, as well of the nature of the wave amplitudes.
Large numbers hypothesis. I - Classical formalism
NASA Technical Reports Server (NTRS)
Adams, P. J.
1982-01-01
A self-consistent formulation of physics at the classical level embodying Dirac's large numbers hypothesis (LNH) is developed based on units covariance. A scalar 'field' phi(x) is introduced and some fundamental results are derived from the resultant equations. Some unusual properties of phi are noted such as the fact that phi cannot be the correspondence limit of a normal quantum scalar field.
Electromagnetically induced classical and quantum Lau effect
NASA Astrophysics Data System (ADS)
Qiu, Tianhui; Yang, Guojian; Xiong, Jun; Xu, Deqin
2016-07-01
We present two schemes of Lau effect for an object, an electromagnetically induced grating generated based on the electromagnetically induced effect. The Lau interference pattern is detected either directly in the way of the traditional Lau effect measurement with a classical thermal light being the imaging light, or indirectly and nonlocally in the way of two-photon coincidence measurement with a pair of entangled photons being the imaging light.
Uniform Additivity in Classical and Quantum Information
NASA Astrophysics Data System (ADS)
Cross, Andrew; Li, Ke; Smith, Graeme
2017-01-01
Information theory quantifies the optimal rates of resource interconversions, usually in terms of entropies. However, nonadditivity often makes evaluating entropic formulas intractable. In a few auspicious cases, additivity allows a full characterization of optimal rates. We study uniform additivity of formulas, which is easily evaluated and captures all known additive quantum formulas. Our complete characterization of uniform additivity exposes an intriguing new additive quantity and identifies a remarkable coincidence—the classical and quantum uniformly additive functions with one auxiliary variable are identical.
Time in classical and in quantum mechanics
NASA Astrophysics Data System (ADS)
Elçi, A.
2010-07-01
This paper presents an analysis of the time concept in classical mechanics from the perspective of the invariants of a motion. The analysis shows that there is a conceptual gap concerning time in the Dirac-Heisenberg-von Neumann formalism and that Bohr's complementarity principle does not fill the gap. In the Dirac-Heisenberg-von Neumann formalism, a particle's properties are represented by Heisenberg matrices. This axiom is the source of the time problem in quantum mechanics.
Lie algebras of classical and stochastic electrodynamics
NASA Astrophysics Data System (ADS)
Neto, J. J. Soares; Vianna, J. D. M.
1994-03-01
The Lie algebras associated with infinitesimal symmetry transformations of third-order differential equations of interest to classical electrodynamics and stochastic electrodynamics have been obtained. The structure constants for a general case are presented and the Lie algebra for each particular application is easily achieved. By the method used here it is not necessary to know the explicit expressions of the infinitesimal generators in order to determine the structure constants of the Lie algebra.
On Logical Error Underlying Classical Mechanics
NASA Astrophysics Data System (ADS)
Kalanov, Temur Z.
2012-03-01
The logical analysis of the general accepted description of mechanical motion of material point M in classical mechanics is proposed. The key idea of the analysis is as follows. Let point M be moved in the positive direction of the axis O 1ptx. Motion is characterized by a change of coordinate x,( t ) -- continuous function of time t(because motion is a change in general). If δ,->;0;δ,;=;0, then δ,;->;0δ,;=;0, i.e., according to practice and formal logic, value of coordinate does not change and, hence, motion does not exist. But, contrary to practice and formal logic, differential calculus and classical mechanics contain the assertion that velocity δ,;->;0;δ,δ,;exists without motion. Then velocity δ,;->;0;δ,δ,;is not real (i.e. not physical) quantity, but fictitious quantity. Therefore, use of non-physical (unreal) quantity (i.e. the first and second derivatives of function) in classical mechanics is a logic error.
The classical model for moment tensors
NASA Astrophysics Data System (ADS)
Tape, Walter; Tape, Carl
2013-12-01
A seismic moment tensor is a description of an earthquake source, but the description is indirect. The moment tensor describes seismic radiation rather than the actual physical process that initiates the radiation. A moment tensor `model' then ties the physical process to the moment tensor. The model is not unique, and the physical process is therefore not unique. In the classical moment tensor model, an earthquake arises from slip along a planar fault, but with the slip not necessarily in the plane of the fault. The model specifies the resulting moment tensor in terms of the slip vector, the fault normal vector and the Lamé elastic parameters, assuming isotropy. We review the classical model in the context of the fundamental lune. The lune is closely related to the space of moment tensors, and it provides a setting that is conceptually natural as well as pictorial. In addition to the classical model, we consider a crack plus double-couple model (CDC model) in which a moment tensor is regarded as the sum of a crack tensor and a double couple.
Acoustical study of classical Peking Opera singing.
Sundberg, Johan; Gu, Lide; Huang, Qiang; Huang, Ping
2012-03-01
Acoustic characteristics of classical opera singing differ considerably between the Western and the Chinese cultures. Singers in the classical Peking opera tradition specialize on one out of a limited number of standard roles. Audio and electroglottograph signals were recorded for four performers of the Old Man role and three performers of the Colorful Face role. Recordings were made of the singers' speech and when they sang recitatives and songs from their roles. Sound pressure level, fundamental frequency, and spectrum characteristics were analyzed. Histograms showing the distribution of fundamental frequency showed marked peaks for the songs, suggesting a scale tone structure. Some of the intervals between these peaks were similar to those used in Western music. Vibrato rate was about 3.5Hz, that is, considerably slower than in Western classical singing. Spectra of vibrato-free tones contained unbroken series of harmonic partials sometimes reaching up to 17 000Hz. Long-term-average spectrum (LTAS) curves showed no trace of a singer's formant cluster. However, the Colorful Face role singers' LTAS showed a marked peak near 3300Hz, somewhat similar to that found in Western pop music singers. The mean LTAS spectrum slope between 700 and 6000Hz decreased by about 0.2dB/octave per dB of equivalent sound level.
Low Mach Number Simulations of Classical Novae
NASA Astrophysics Data System (ADS)
Krueger, Brendan K.; Calder, A. C.; Zingale, M.; Almgren, A. S.; Bell, J. B.; Nonaka, A.
2012-01-01
Classical novae are thermonuclear explosions in the accreted layer on the surface of a white dwarf star. The manner in which convective flow interacts with the underlying white dwarf plays a critical role in determining the composition of the accreted layer and the energy release in the outburst. Studies of these complex reactive flows are typically limited by the available computing technology. I am applying a new low Mach number simulation code, MAESTRO, to study classical novae. MAESTRO filters out acoustic waves, allowing much larger time steps without restricting temperature or density perturbations, which in turn enables simulations of much longer time scales. With this unique tool, I have been exploring the development of convection and subsequent mixing in classical novae and their impact on the overall evolution of the outburst. I will present results from multidimensional simulations and quantify the character of the convection and mixing. This work was supported by NASA under grant No. NNX09AD19G and LLNL under contract B59328.
Defining Astrology in Ancient and Classical History
NASA Astrophysics Data System (ADS)
Campion, Nicholas
2015-05-01
Astrology in the ancient and classical worlds can be partly defined by its role, and partly by the way in which scholars spoke about it. The problem is complicated by the fact that the word is Greek - it has no Babylonian or Egyptian cognates - and even in Greece it was interchangeable with its cousin, 'astronomy'. Yet if we are to understand the role of the sky, stars and planets in culture, debates about the nature of ancient astrology, by both classical and modern scholars, must be taken into account. This talk will consider modern scholars' typologies of ancient astrology, together with ancient debates from Cicero in the 1st century BC, to Plotinus (204/5-270 AD) and Isidore of Seville (c. 560 - 4 April 636). It will consider the implications for our understanding of astronomy's role in culture, and conclude that in the classical period astrology may be best understood through its diversity and allegiance to competing philosophies, and that its functions were therefore similarly varied.
Large classical universes emerging from quantum cosmology
Pinto-Neto, Nelson
2009-04-15
It is generally believed that one cannot obtain a large universe from quantum cosmological models without an inflationary phase in the classical expanding era because the typical size of the universe after leaving the quantum regime should be around the Planck length, and the standard decelerated classical expansion after that is not sufficient to enlarge the universe in the time available. For instance, in many quantum minisuperspace bouncing models studied in the literature, solutions where the universe leaves the quantum regime in the expanding phase with appropriate size have negligible probability amplitude with respect to solutions leaving this regime around the Planck length. In this paper, I present a general class of moving Gaussian solutions of the Wheeler-DeWitt equation where the velocity of the wave in minisuperspace along the scale factor axis, which is the new large parameter introduced in order to circumvent the above-mentioned problem, induces a large acceleration around the quantum bounce, forcing the universe to leave the quantum regime sufficiently big to increase afterwards to the present size, without needing any classical inflationary phase in between, and with reasonable relative probability amplitudes with respect to models leaving the quantum regime around the Planck scale. Furthermore, linear perturbations around this background model are free of any trans-Planckian problem.
Quantum vs. classical walks with memory two
NASA Astrophysics Data System (ADS)
Dimcovic, Zlatko; Kovchegov, Yevgeniy
2010-03-01
Quantum walks is an emerging field in quantum computing. It is expected to become the next most effective tool in speeding up quantum algorithms, possibly achieving the similar gain in speed as was the case with Gibbs sampling in classical computing. There already exist examples of super-exponential speed up using only quantum walks. Markov chains, or random walks on graphs, have many uses in physics; and walks with memory are standard models for a number of phenomena. We study persistent quantum walks, and compare them with equivalent classical Markov processes. The first question to ask is how the mixing time compares between persistent quantum and classical walks. Since quantum walks are generated by unitary matrices, they do not converge to a stationary state. The mixing time is then naturally introduced via a limiting distribution defined as the average of the probability distributions over time (Cesaro sum). We compare the mixing times, along with other properties, using numerical methods and spectral analysis. Our preliminary results indicate a significant speedup in some cases, and a number of other interesting aspects of quantum walks.
Complex Classical Mechanics of a QES Potential
NASA Astrophysics Data System (ADS)
Bhabani Prasad, Mandal; Sushant, S. Mahajan
2015-10-01
We study a combined parity (P) and time reversal (T) invariant non-Hermitian quasi-exactly solvable (QES) potential, which exhibits PT phase transition, in the complex plane classically to demonstrate different quantum effects. The particle with real energy makes closed orbits around one of the periodic wells of the complex potential depending on the initial condition. However interestingly the particle escapes to an open orbits even with real energy if it is placed beyond a certain distance from the center of the well. On the other hand when the particle energy is complex the trajectory is open and the particle tunnels back and forth between two wells which are separated by a classically forbidden path. The tunneling time is calculated for different pair of wells and is shown to vary inversely with the imaginary component of energy. Our study reveals that spontaneous PT symmetry breaking does not affect the qualitative features of the particle trajectories in the analogous complex classical model. Support from Department of Science and Technology (DST), Govt. of India under SERC Project Sanction Grant No. SR/S2/HEP-0009/2012
FSH isoform pattern in classic galactosemia.
Gubbels, Cynthia S; Thomas, Chris M G; Wodzig, Will K W H; Olthaar, André J; Jaeken, Jaak; Sweep, Fred C G J; Rubio-Gozalbo, M Estela
2011-04-01
Female classic galactosemia patients suffer from primary ovarian insufficiency (POI). The cause for this long-term complication is not fully understood. One of the proposed mechanisms is that hypoglycosylation of complex molecules, a known secondary phenomenon of galactosemia, leads to FSH dysfunction. An earlier study showed less acidic isoforms of FSH in serum samples of two classic galactosemia patients compared to controls, indicating hypoglycosylation. In this study, FSH isoform patterns of five classic galactosemia patients with POI were compared to the pattern obtained in two patients with a primary glycosylation disorder (phosphomannomutase-2-deficient congenital disorders of glycosylation, PMM2-CDG) and POI, and in five postmenopausal women as controls. We used FPLC chromatofocussing with measurement of FSH concentration per fraction, and discovered that there were no significant differences between galactosemia patients, PMM2-CDG patients and postmenopausal controls. Our results do not support that FSH dysfunction due to a less acidic isoform pattern because of hypoglycosylation is a key mechanism of POI in this disease.
Bridging quantum and classical plasmonics with a quantum-corrected model.
Esteban, Ruben; Borisov, Andrei G; Nordlander, Peter; Aizpurua, Javier
2012-05-08
Electromagnetic coupling between plasmonic resonances in metallic nanoparticles allows for engineering of the optical response and generation of strong localized near-fields. Classical electrodynamics fails to describe this coupling across sub-nanometer gaps, where quantum effects become important owing to non-local screening and the spill-out of electrons. However, full quantum simulations are not presently feasible for realistically sized systems. Here we present a novel approach, the quantum-corrected model (QCM), that incorporates quantum-mechanical effects within a classical electrodynamic framework. The QCM approach models the junction between adjacent nanoparticles by means of a local dielectric response that includes electron tunnelling and tunnelling resistivity at the gap and can be integrated within a classical electrodynamical description of large and complex structures. The QCM predicts optical properties in excellent agreement with fully quantum mechanical calculations for small interacting systems, opening a new venue for addressing quantum effects in realistic plasmonic systems.
Classical electromagnetic fields from quantum sources in heavy-ion collisions
NASA Astrophysics Data System (ADS)
Holliday, Robert; McCarty, Ryan; Peroutka, Balthazar; Tuchin, Kirill
2017-01-01
Electromagnetic fields are generated in high energy nuclear collisions by spectator valence protons. These fields are traditionally computed by integrating the Maxwell equations with point sources. One might expect that such an approach is valid at distances much larger than the proton size and thus such a classical approach should work well for almost the entire interaction region in the case of heavy nuclei. We argue that, in fact, the contrary is true: due to the quantum diffusion of the proton wave function, the classical approximation breaks down at distances of the order of the system size. We compute the electromagnetic field created by a charged particle described initially as a Gaussian wave packet of width 1 fm and evolving in vacuum according to the Klein-Gordon equation. We completely neglect the medium effects. We show that the dynamics, magnitude and even sign of the electromagnetic field created by classical and quantum sources are different.
Mesoscopic systems: classical irreversibility and quantum coherence.
Barbara, Bernard
2012-09-28
Mesoscopic physics is a sub-discipline of condensed-matter physics that focuses on the properties of solids in a size range intermediate between bulk matter and individual atoms. In particular, it is characteristic of a domain where a certain number of interacting objects can easily be tuned between classical and quantum regimes, thus enabling studies at the border of the two. In magnetism, such a tuning was first realized with large-spin magnetic molecules called single-molecule magnets (SMMs) with archetype Mn(12)-ac. In general, the mesoscopic scale can be relatively large (e.g. micrometre-sized superconducting circuits), but, in magnetism, it is much smaller and can reach the atomic scale with rare earth (RE) ions. In all cases, it is shown how quantum relaxation can drastically reduce classical irreversibility. Taking the example of mesoscopic spin systems, the origin of irreversibility is discussed on the basis of the Landau-Zener model. A classical counterpart of this model is described enabling, in particular, intuitive understanding of most aspects of quantum spin dynamics. The spin dynamics of mesoscopic spin systems (SMM or RE systems) becomes coherent if they are well isolated. The study of the damping of their Rabi oscillations gives access to most relevant decoherence mechanisms by different environmental baths, including the electromagnetic bath of microwave excitation. This type of decoherence, clearly seen with spin systems, is easily recovered in quantum simulations. It is also observed with other types of qubits such as a single spin in a quantum dot or a superconducting loop, despite the presence of other competitive decoherence mechanisms. As in the molecular magnet V(15), the leading decoherence terms of superconducting qubits seem to be associated with a non-Markovian channel in which short-living entanglements with distributions of two-level systems (nuclear spins, impurity spins and/or charges) leading to 1/f noise induce τ(1)-like
Creativity and personality in classical, jazz and folk musicians.
Benedek, Mathias; Borovnjak, Barbara; Neubauer, Aljoscha C; Kruse-Weber, Silke
2014-06-01
The music genre of jazz is commonly associated with creativity. However, this association has hardly been formally tested. Therefore, this study aimed at examining whether jazz musicians actually differ in creativity and personality from musicians of other music genres. We compared students of classical music, jazz music, and folk music with respect to their musical activities, psychometric creativity and different aspects of personality. In line with expectations, jazz musicians are more frequently engaged in extracurricular musical activities, and also complete a higher number of creative musical achievements. Additionally, jazz musicians show higher ideational creativity as measured by divergent thinking tasks, and tend to be more open to new experiences than classical musicians. This study provides first empirical evidence that jazz musicians show particularly high creativity with respect to domain-specific musical accomplishments but also in terms of domain-general indicators of divergent thinking ability that may be relevant for musical improvisation. The findings are further discussed with respect to differences in formal and informal learning approaches between music genres.
Introduction of a Classical Level in Quantum Theory
NASA Astrophysics Data System (ADS)
Prosperi, G. M.
2016-11-01
In an old paper of our group in Milano a formalism was introduced for the continuous monitoring of a system during a certain interval of time in the framework of a somewhat generalized approach to quantum mechanics (QM). The outcome was a distribution of probability on the space of all the possible continuous histories of a set of quantities to be considered as a kind of coarse grained approximation to some ordinary quantum observables commuting or not. In fact the main aim was the introduction of a classical level in the context of QM, treating formally a set of basic quantities, to be considered as beables in the sense of Bell, as continuously taken under observation. However the effect of such assumption was a permanent modification of the Liouville-von Neumann equation for the statistical operator by the introduction of a dissipative term which is in conflict with basic conservation rules in all reasonable models we had considered. Difficulties were even encountered for a relativistic extension of the formalism. In this paper I propose a modified version of the original formalism which seems to overcome both difficulties. First I study the simple models of an harmonic oscillator and a free scalar field in which a coarse grain position and a coarse grained field respectively are treated as beables. Then I consider the more realistic case of spinor electrodynamics in which only certain coarse grained electric and magnetic fields are introduced as classical variables and no matter related quantities.
Creativity and personality in classical, jazz and folk musicians
Benedek, Mathias; Borovnjak, Barbara; Neubauer, Aljoscha C.; Kruse-Weber, Silke
2014-01-01
The music genre of jazz is commonly associated with creativity. However, this association has hardly been formally tested. Therefore, this study aimed at examining whether jazz musicians actually differ in creativity and personality from musicians of other music genres. We compared students of classical music, jazz music, and folk music with respect to their musical activities, psychometric creativity and different aspects of personality. In line with expectations, jazz musicians are more frequently engaged in extracurricular musical activities, and also complete a higher number of creative musical achievements. Additionally, jazz musicians show higher ideational creativity as measured by divergent thinking tasks, and tend to be more open to new experiences than classical musicians. This study provides first empirical evidence that jazz musicians show particularly high creativity with respect to domain-specific musical accomplishments but also in terms of domain-general indicators of divergent thinking ability that may be relevant for musical improvisation. The findings are further discussed with respect to differences in formal and informal learning approaches between music genres. PMID:24895472
Some Complex Pressure Effects on Spectra from Simple Classical Mechanics
NASA Astrophysics Data System (ADS)
Hartmann, Jean-Michel
2016-06-01
I will first recall how [the two Newton's equations, 1rst year of university] one can very easily compute the rotational and translational classical dynamics of an ensemble of linear molecules interacting through an (input) pair-wise intermolecular potential. These Classical Molecular Dynamics Simulations (CMDS), which provide the time dependence of the positions and axis-orientations of gas phase molecules, are then used to calculate a number of pressure effects manifesting in absorption and scattering spectra. The cases of CO2, O2 and N2 will be considered, systems for which fully quantum approaches are intractable, and comparisons with measured data will be made, free of any adjusted parameter. I will show that, with a few input ingredients from literature (molecule geometry, electric multipoles, polarizabilities, ...) an no adjusted parameter, excellent agreements with various measurements are obtained. Examples will be given for: (1) Collision induced absorption (due to the interaction induced dipole) ; (2) The far wings of absorption (due to the dipole) and light scattering (due to polarizability) bands ; (3) The broadening and shapes (with their deviations from the Voigt profile) of individual absorption lines for both "free" and spatially tightly confined gases. If times allows, additional demonstrations of the interest of CMDS will be given by considering line-mixing effects and the relaxation of laser-kicked molecules.
Metric and classical fidelity uncertainty relations for random unitary matrices
NASA Astrophysics Data System (ADS)
Adamczak, Radosław
2017-03-01
We analyze uncertainty relations on finite dimensional Hilbert spaces expressed in terms of classical fidelity, which are stronger than metric uncertainty relations introduced by Fawzi, Hayden and Sen. We establish the validity of fidelity uncertainty relations for random unitary matrices with optimal parameters (up to universal constants) which improves upon known results for the weaker notion of metric uncertainty. This result is then applied to locking classical information in quantum states and allows to obtain optimal locking in Hellinger distance, improving upon previous results on locking in the total variation distance, both by strengthening the metric used and by improving the dependence on parameters. We also show that general probabilistic estimates behind the main theorem can be used to prove existence of data hiding schemes with Bayesian type guarantees. As a byproduct of our approach we obtain existence of almost Euclidean subspaces of the matrix spaces \\ell 1n≤ft(\\ell 2m\\right) with a better dimension/distortion dependence than allowed in previously known constructions.
The Quantization of Classical Fields Equations and the Cyclic Universe
NASA Astrophysics Data System (ADS)
Guo, Zhu Ho
2011-03-01
Basically nothing is known definitely about the early universe. Einstein gravity field equation, based on general relativity and the grand unified field theories, has been employed for the study of the early universe but has not provided definitive answers. As detailed in this article, for understanding the enormous energy of the early universe, classical field equations, including general relativity, must be quantized. The quantization of general relativity by using Feynman's formulation has also faced difficulties. Unified Field theory also needs quantization of Einstein equation for studying the universe. New interpretations of the uncertainty principles indicates that physical quantities should have both lower and upper limits. Physical quantities form pairs, couple and complement to each other performing cyclic process. Their limits should overcome the limits of coupling formulae. In this article, cyclic universe theories are reviewed and limits coupling formulae are derived for pairs of physical quantities. By means of these limits coupling formulae, most of the classical field equations, including Einstein equation, are quantized. The equations derived are used successfully to describe quantitatively the whole development of our cyclic universe. Some long-standing questions in cosmology may be answered with this approach, such as the origin of quasar and the existence of other universes.
Quiver theories for moduli spaces of classical group nilpotent orbits
NASA Astrophysics Data System (ADS)
Hanany, Amihay; Kalveks, Rudolph
2016-06-01
We approach the topic of Classical group nilpotent orbits from the perspective of the moduli spaces of quivers, described in terms of Hilbert series and generating functions. We review the established Higgs and Coulomb branch quiver theory constructions for A series nilpotent orbits. We present systematic constructions for BCD series nilpotent orbits on the Higgs branches of quiver theories defined by canonical partitions; this paper collects earlier work into a systematic framework, filling in gaps and providing a complete treatment. We find new Coulomb branch constructions for above minimal nilpotent orbits, including some based upon twisted affine Dynkin diagrams. We also discuss aspects of 3 d mirror symmetry between these Higgs and Coulomb branch constructions and explore dualities and other relationships, such as HyperKähler quotients, between quivers. We analyse all Classical group nilpotent orbit moduli spaces up to rank 4 by giving their unrefined Hilbert series and the Highest Weight Generating functions for their decompositions into characters of irreducible representations and/or Hall Littlewood polynomials.
Grand challenges in quantum-classical modeling of molecule-surface interactions.
Herbers, Claudia R; Li, Chunli; van der Vegt, Nico F A
2013-05-30
A detailed understanding of the adsorption of small molecules or macromolecules to a materials surface is of importance, for example, in the context of material and biomaterial research. Classical atomistic simulations in principle provide microscopic insight in the complex entropic and enthalpic interplay at the interface. However, an application of classical atomistic simulation techniques to such interface systems is a nontrivial problem, mostly because commonly used force fields cannot be straightforwardly applied, as they are usually developed to reproduce bulk properties of either solids or liquids but not the interfacial region between two phases. Therefore, a dual-scale modeling approach has often been the method of choice in the past, in which the classical force field is parameterized such that quantum chemical information on near-surface conformations and adsorption energies is reproduced by the classical force field. We will discuss in this review the current state-of-the-art of quantum-classical modeling of molecule-surface interactions and outline the major challenges in this field. In this context, we will, among other things, lay emphasis on discussing ways to obtain representable force fields and propose systematic and system-independent strategies to optimize the quantum-classical fitting procedure.
Dynamics in the quantum/classical limit based on selective use of the quantum potential
Garashchuk, Sophya Dell’Angelo, David; Rassolov, Vitaly A.
2014-12-21
A classical limit of quantum dynamics can be defined by compensation of the quantum potential in the time-dependent Schrödinger equation. The quantum potential is a non-local quantity, defined in the trajectory-based form of the Schrödinger equation, due to Madelung, de Broglie, and Bohm, which formally generates the quantum-mechanical features in dynamics. Selective inclusion of the quantum potential for the degrees of freedom deemed “quantum,” defines a hybrid quantum/classical dynamics, appropriate for molecular systems comprised of light and heavy nuclei. The wavefunction is associated with all of the nuclei, and the Ehrenfest, or mean-field, averaging of the force acting on the classical degrees of freedom, typical of the mixed quantum/classical methods, is avoided. The hybrid approach is used to examine evolution of light/heavy systems in the harmonic and double-well potentials, using conventional grid-based and approximate quantum-trajectory time propagation. The approximate quantum force is defined on spatial domains, which removes unphysical coupling of the wavefunction fragments corresponding to distinct classical channels or configurations. The quantum potential, associated with the quantum particle, generates forces acting on both quantum and classical particles to describe the backreaction.