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Sample records for 20-year time period

  1. Detecting land cover change over a 20 year time period in the Niagara Escarpment Plan using satellite remote sensing

    NASA Astrophysics Data System (ADS)

    Waite, Holly

    The Niagara Escarpment is one of Southern Ontario's most important landscapes. Due to the nature of the landform and its location, the Escarpment is subject to various development pressures including urban expansion, mineral resource extraction, agricultural practices and recreation. In 1985, Canada's first large scale environmentally based land use plan was put in place to ensure that only development that is compatible with the Escarpment occurred within the Niagara Escarpment Plan (NEP). The southern extent of the NEP is of particular interest in this study, since a portion of the Plan is located within the rapidly expanding Greater Toronto Area (GTA). The Plan area located in the Regional Municipalities of Hamilton and Halton represent both urban and rural geographical areas respectively, and are both experiencing development pressures and subsequent changes in land cover. Monitoring initiatives on the NEP have been established, but have done little to identify consistent techniques for monitoring land cover on the Niagara Escarpment. Land cover information is an important part of planning and environmental monitoring initiatives. Remote sensing has the potential to provide frequent and accurate land cover information over various spatial scales. The goal of this research was to examine land cover change in the Regional Municipalities of Hamilton and Halton portions of the NEP. This was achieved through the creation of land cover maps for each region using Landsat 5 Thematic Mapper (TM) remotely sensed data. These maps aided in determining the qualitative and quantitative changes that had occurred in the Plan area over a 20 year time period from 1986 to 2006. Change was also examined based on the NEP's land use designations, to determine if the Plan policy has been effective in protecting the Escarpment. To obtain land cover maps, five different supervised classification methods were explored: Minimum Distance, Mahalanobis Distance, Maximum Likelihood, Object

  2. Environmental Volunteering and Health Outcomes over a 20-Year Period

    ERIC Educational Resources Information Center

    Pillemer, Karl; Fuller-Rowell, Thomas E.; Reid, M. C.; Wells, Nancy M.

    2010-01-01

    Purpose: This study tested the hypothesis that volunteering in environmental organizations in midlife is associated with greater physical activity and improved mental and physical health over a 20-year period. Design and Methods: The study used data from two waves (1974 and 1994) of the Alameda County Study, a longitudinal study of health and…

  3. Changes in plant species composition of coastal dune habitats over a 20-year period

    PubMed Central

    Del Vecchio, Silvia; Prisco, Irene; Acosta, Alicia T. R.; Stanisci, Angela

    2015-01-01

    Coastal sandy ecosystems are increasingly being threatened by human pressure, causing loss of biodiversity, habitat degradation and landscape modifications. However, there are still very few detailed studies focussing on compositional changes in coastal dune plant communities over time. In this work, we investigated how coastal dune European Union (EU) habitats (from pioneer annual beach communities to Mediterranean scrubs on the landward fixed dunes) have changed during the last 20 years. Using phytosociological relevés conducted in 1989–90 and in 2010–12, we investigated changes in floristic composition over time. We then compared plant cover and the proportion of ruderal, alien and habitat diagnostic species (‘focal species’) in the two periods. Finally, we used Ellenberg indicator values to define the ‘preferences’ of the plant species for temperature and moisture. We found that only fore dune habitats showed significant differences in species cover between the two time periods, with higher plant cover in the more recent relevés and a significant increase in thermophilic species. Although previous studies have demonstrated consistent habitat loss in this area, we observed that all coastal dune plant communities remain well represented, after a 20-year period. However, fore dunes have been experiencing significant compositional changes. Although we cannot confirm whether the observed changes are strictly related to climatic changes, to human pressure or to both, we hypothesize that a moderate increment in average yearly temperature may have promoted the increase in plant cover and the spread of thermophilic species. Thus, even though human activities are major driving forces of change in coastal dune vegetation, at the community scale climatic factors may also play important roles. Our study draws on re-visitation studies which appear to constitute a powerful tool for the assessment of the conservation status of EU habitats. PMID:25750408

  4. Changes in plant species composition of coastal dune habitats over a 20-year period.

    PubMed

    Del Vecchio, Silvia; Prisco, Irene; Acosta, Alicia T R; Stanisci, Angela

    2015-03-05

    Coastal sandy ecosystems are increasingly being threatened by human pressure, causing loss of biodiversity, habitat degradation and landscape modifications. However, there are still very few detailed studies focussing on compositional changes in coastal dune plant communities over time. In this work, we investigated how coastal dune European Union (EU) habitats (from pioneer annual beach communities to Mediterranean scrubs on the landward fixed dunes) have changed during the last 20 years. Using phytosociological relevés conducted in 1989-90 and in 2010-12, we investigated changes in floristic composition over time. We then compared plant cover and the proportion of ruderal, alien and habitat diagnostic species ('focal species') in the two periods. Finally, we used Ellenberg indicator values to define the 'preferences' of the plant species for temperature and moisture. We found that only fore dune habitats showed significant differences in species cover between the two time periods, with higher plant cover in the more recent relevés and a significant increase in thermophilic species. Although previous studies have demonstrated consistent habitat loss in this area, we observed that all coastal dune plant communities remain well represented, after a 20-year period. However, fore dunes have been experiencing significant compositional changes. Although we cannot confirm whether the observed changes are strictly related to climatic changes, to human pressure or to both, we hypothesize that a moderate increment in average yearly temperature may have promoted the increase in plant cover and the spread of thermophilic species. Thus, even though human activities are major driving forces of change in coastal dune vegetation, at the community scale climatic factors may also play important roles. Our study draws on re-visitation studies which appear to constitute a powerful tool for the assessment of the conservation status of EU habitats.

  5. Survival Trends After Surgery for Acute Subdural Hematoma in Adults Over a 20-year Period

    PubMed Central

    Fountain, Daniel M.; Kolias, Angelos G.; Lecky, Fiona E.; Bouamra, Omar; Lawrence, Thomas; Adams, Hadie; Bond, Simon J.; Hutchinson, Peter J.

    2017-01-01

    Objective: We sought to determine 30-day survival trends and prognostic factors following surgery for acute subdural hematomas (ASDHs) in England and Wales over a 20-year period. Summary of Background Data: ASDHs are still considered the most lethal type of traumatic brain injury. It remains unclear whether the adjusted odds of survival have improved significantly over time. Methods: Using the Trauma Audit and Research Network (TARN) database, we analyzed ASDH cases in the adult population (>16 yrs) treated surgically between 1994 and 2013. Two thousand four hundred ninety-eight eligible cases were identified. Univariable and multiple logistic regression analyses were performed, using multiple imputation for missing data. Results: The cohort was 74% male with a median age of 48.9 years. Over half of patients were comatose at presentation (53%). Mechanism of injury was due to a fall (<2 m 34%, >2 m 24%), road traffic collision (25%), and other (17%). Thirty-six per cent of patients presented with polytrauma. Gross survival increased from 59% in 1994 to 1998 to 73% in 2009 to 2013. Under multivariable analysis, variables independently associated with survival were year of injury, Glasgow Coma Scale, Injury Severity Score, age, and pupil reactivity. The time interval from injury to craniotomy and direct admission to a neurosurgical unit were not found to be significant prognostic factors. Conclusions: A significant improvement in survival over the last 20 years was observed after controlling for multiple prognostic factors. Prospective trials and cohort studies are expected to elucidate the distribution of functional outcome in survivors. PMID:27172128

  6. Comparison of Cardiovascular Risk Factors in Different Areas of Health Care Over a 20-Year Period

    PubMed Central

    Jardim, Thiago Veiga; Sousa, Ana Luiza Lima; Povoa, Thais Rolim; Barroso, Weimar Sebba; Chinem, Brunela; Jardim, Paulo Cesar Veiga

    2014-01-01

    Background Cardiovascular diseases (CVDs) are the leading cause of death worldwide. Knowledge about cardiovascular risk factors (CVRFs) in young adults and their modification over time are measures that change the risks and prevent CVDs. Objectives To determine the presence of CVRFs and their changes in different health care professionals over a period of 20 years. Methods All students of medicine, nursing, nutrition, odontology, and pharmacy departments of Federal University of Goiás who agreed to participate in this study were evaluated when they started their degree courses and 20 years afterward. Questionnaires on CVRFs [systemic arterial hypertension (SAH), diabetes mellitus, dyslipidemia, and family history of early CVD, smoking, alcohol consumption, and sedentarism] were administered. Cholesterol levels, blood sugar levels, blood pressure, weight, height, and body mass index were determined. The Kolmogorov-Smirnov test was used to evaluate distribution, the chi-square test was used to compare different courses and sexes, and the McNemar test was used for comparing CVRFs. The significance level was set at a p value of < 0.05. Results The first stage of the study included 281 individuals (91% of all the students), of which 62.9% were women; the mean age was 19.7 years. In the second stage, 215 subjects were reassessed (76% of the initial sample), of which 59.07% were women; the mean age was 39.8 years. The sample mostly consisted of medical students (with a predominance of men), followed by nursing, nutrition, and pharmacy students, with a predominance of women (p < 0.05). Excessive weight gain, SAH, and dyslipidemia were observed among physicians and dentists (p < 0.05). Excessive weight gain and SAH and a reduction in sedentarism (p < 0.05) were observed among pharmacists. Among nurses there was an increase in excessive weight and alcohol consumption (p < 0.05). Finally, nutritionists showed an increase in dyslipidemia (p < 0.05). Conclusion In general

  7. Bibliometric analysis of global environmental assessment research in a 20-year period

    SciTech Connect

    Li, Wei Zhao, Yang

    2015-01-15

    Based on the samples of 113,468 publications on environmental assessment (EA) from the past 20 years, we used a bibliometric analysis to study the literature in terms of trends of growth, subject categories and journals, international collaboration, geographic distribution of publications, and scientific research issues. By applying thresholds to network centralities, a core group of countries can be distinguished as part of the international collaboration network. A frequently used keywords analysis found that the priority in assessment would gradually change from project environmental impact assessment (EIA) to strategic environmental assessment (SEA). Decision-theoretic approaches (i.e., environmental indicator selection, life cycle assessment, etc.), along with new technologies and methods (i.e., the geographic information system and modeling) have been widely applied in the EA research field over the past 20 years. Hot spots such as “biodiversity” and “climate change” have been emphasized in current EA research, a trend that will likely continue in the future. The h-index has been used to evaluate the research quality among countries all over the world, while the improvement of developing countries' EA systems is becoming a popular research topic. Our study reveals patterns in scientific outputs and academic collaborations and serves as an alternative and innovative way of revealing global research trends in the EA research field.

  8. Insights into the dynamics of Etna volcano from 20-year time span microgravity and GPS observations

    NASA Astrophysics Data System (ADS)

    Bonforte, Alessandro; Fanizza, Giovanni; Greco, Filippo; Matera, Alfredo; Sulpizio, Roberto

    2016-04-01

    A common ground deformation and microgravity array of benchmarks lies on the southern slope of Mt. Etna volcano and is routinely measured by GPS and relative gravimetry methods. The array was installed for monitoring the ground motion and underground mass changes along the southern rift of the volcano and data are usually processed and interpreted independently. The benchmarks have been installed mainly along a main road crossing the southern side of the volcano with an E-W direction and reaching 2000 m of altitude. The gravity array covers the entire path of the road, while the ground deformation one only the upper one, due to the woods at lower altitude preventing good GPS measurements. Furthermore, microgravity surveys are usually carried out more frequently with respect to the GPS ones. In this work, an integrated analysis of microgravity and ground deformation is performed over a 20-year time span (1994-2014). Gravity variations have been first corrected for the free-air effect using the GPS observed vertical deformation and the theoretical vertical gravity gradient (-308.6 μGal/m). The free-air corrected gravity changes were then reduced from the high frequency variations (noise) and the seasonal fluctuations, mainly due to water-table fluctuations. This long-term dataset constitutes a unique opportunity to examine the behavior of Etna in a period in which the volcano exhibited different styles of activity characterized by recharging phases, flank eruptions and fountaining episodes. The gravity and deformation data allow investigating the response of the volcano in a wider perspective providing insights into the definition of its dynamic behavior and posing the basis to track the unrest evolution and to forecast the style of the eruption. The joint analysis highlights common periods, in which the signals underwent contemporaneous changes occurring mainly in the central and eastern stations. On the other hand, no significant changes in the behavior of

  9. Reports of child sexual abuse of boys and girls: Longitudinal trends over a 20-year period in Victoria, Australia.

    PubMed

    Mathews, Ben; Bromfield, Leah; Walsh, Kerryann; Cheng, Qinglu; Norman, Rosana E

    2017-02-17

    Although prevalence studies show girls are more frequently sexually abused than boys, a significant proportion of boys also experience child sexual abuse (CSA). The challenges for public policy are amplified for boys due to less developed public and professional sensitisation to boys' experiences, conceptions of masculinity, and less research on boys including into reporting trends and outcomes. We conducted a 20-year longitudinal time-trend analysis of government data to identify reporting trends and report outcomes for CSA in Victoria, Australia from 1993 to 2012. We stratified by child gender and reporter status. Results indicate a new sensitisation to CSA, especially for boys, although this trend was not stable. Marked change occurred in the last five years, likely influenced by major social and political events. Comparison over time revealed that from 1993 to 2012, the rate of reporting of boys increased 2.6-fold whereas there was a 1.5-fold increase for girls. Comparing genders, with regards to rate of reporting, in 1993, the sex ratio of girls to boys was 2:1, while by 2012 this ratio changed to 1.14:1. Reports by police and other mandated reporters accounted for the majority of the increase in reports over the 20-year period, suggesting unequal sensitisation. Positive report outcomes (i.e. substantiations, findings of harm, and referral to services) increased twelve-fold for boys, and nearly five-fold for girls, indicating the increased levels of reports were based in actual clinical need. Most of this increase occurred from 2009 to 2012, influenced by a compound of social, political and agency-related factors.

  10. Incidence of Hepatitis C Infection among Prisoners by Routine Laboratory Values during a 20-Year Period

    PubMed Central

    Marco, Andrés; Gallego, Carlos; Caylà, Joan A.

    2014-01-01

    Background To estimate the incidence of Hepatitis C virus (HCV) and the predictive factors through repeated routine laboratory analyses. Methods An observational cohort study was carried out in Quatre Camins Prison, Barcelona. The study included subjects with an initial negative HCV result and routine laboratory analyses containing HCV serology from 1992 to 2011. The incidence of infection was calculated for the study population and for sub-groups by 100 person-years of follow-up (100 py). The predictive factors were determined through Kaplan-Meier curves and a Cox regression. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated. Results A total of 2,377 prisoners were included with a median follow-up time of 1,540.9 days per patient. Among the total population, 117 HCV seroconversions were detected (incidence of 1.17/100 py). The incidence was higher between 1992 and 1995 (2.57/100 py), among cases with HIV co-infection (8.34/100 py) and among intravenous drug users (IDU) without methadone treatment (MT) during follow-up (6.66/100 py). The incidence rate of HCV seroconversion among cases with a history of IDU and current MT was 1.35/100 py, which is close to that of the total study population. The following variables had a positive predictive value for HCV infection: IDU (p<0.001; HR = 7,30; CI: 4.83–11.04), Spanish ethnicity (p = 0.009; HR = 2,03; CI: 1.93–3.44) and HIV infection (p = 0.015; HR = 1.97; CI: 1.14–3.39). Conclusion The incidence of HCV infection among prisoners was higher during the first part of the study and among IDU during the entire study period. Preventative programs should be directed toward this sub-group of the prison population. PMID:24587394

  11. Acute myocardial infarction incidence in immigrants to Sweden. Country of birth, time since immigration, and time trends over 20 years.

    PubMed

    Hedlund, Ebba; Lange, Anders; Hammar, Niklas

    2007-01-01

    This study investigates incidence of first acute myocardial infarction (MI) among foreign born persons in Sweden using case control methods, taking into consideration country of birth, gender, socio-economic group and time since immigration and evaluates if the decreasing incidence of MI in Sweden during the study period was also present in immigrants. The study base consisted of persons 30-74 years of age in Stockholm County 1977-96. All incident cases of first acute MI in the study population were identified using registers of hospital discharges and deaths. Controls were selected randomly from the study base and the sampling fractions were known, enabling estimates of person time at risk. Foreign born subjects had a higher incidence of MI than subjects born in Sweden (men RR[Relative risk]=1,17; 95% CI 1,13-1,21; women RR = 1,15; 95% CI 1,09-1,21) after adjustment for calendar year, age and socio-economic group. An increased incidence was present primarily in subjects born in Finland, other Nordic countries, Poland, Turkey, Syria and South Asia in both genders, from the Netherlands among men and from Iraq among women and was still present after more than 20 years in Sweden. The incidence rate of MI 1977-96 among foreign born persons followed the general decline in the Swedish population. We conclude that foreign born persons in Sweden have an increased incidence of first MI which persists several years after immigration and is not explained by socio-economic differences. It is likely that this to an important extent has a background in factors in the country of origin.

  12. Ice-core data evidence for a prominent near 20 year time-scale of the Atlantic Multidecadal Oscillation

    NASA Astrophysics Data System (ADS)

    Chylek, Petr; Folland, Chris K.; Dijkstra, Henk A.; Lesins, Glen; Dubey, Manvendra K.

    2011-07-01

    Using five ice core data sets combined into a single time series, we provide for the first time strong observational evidence for two distinct time scales of Arctic temperature fluctuation that are interpreted as variability associated with the Atlantic Multidecadal Oscillation (AMO). The dominant and the only statistically significant multidecadal signal has a time scale of about 20 years. The longer multidecadal variability of 45-85 years is not well defined and none of the time scales in this band is statistically significant. We compare these observed temperature fluctuations with results of coupled climate model simulations (HadCM3 and GFDL CM2.1). Both the 20-25 year and a variable longer AMO time scale are prominent in the models' long control runs. This periodicity supports our conjecture that the observed ice core fluctuations are a signature of the AMO. The robustness of this short time scale period in both observations and model simulations has implications for understanding the dominant AMO mechanisms in climate.

  13. Intestinal stoma in patients with colorectal cancer from the perspective of 20-year period of clinical observation

    PubMed Central

    Banaszkiewicz, Zbigniew; Woda, Łukasz P.; Tojek, Krzysztof; Jarmocik, Paweł; Jawień, Arkadiusz

    2015-01-01

    Introduction Intestinal stoma is a procedure most often performed in patients with colorectal cancer. Aim To identify the percentage of patients with colorectal cancer in which the intestinal stoma was performed. Material and methods We retrospectively analysed 443 patients treated during a 20-year period (1994–2013) due to colorectal cancer, in which the intestinal stoma was made during the first surgical intervention. Results In the second analysed decade, a significant decrease in the percentage of created stomas, definitive stomas in particular, was observed. Stomas were made significantly more often in patients with a tumour located in the rectum, the left half of the colon, and in patients undergoing urgent surgeries. An increased incidence of intestinal stomas was associated with a higher severity of illness and higher proportion of unresectable and non-radical procedures. The definitive stomas were significantly more often made in men and in patients with tumours located in the rectum, whereas temporary stomas were created significantly more often in patients undergoing urgent operations. Conclusions In the last decade (2004–2013) the number of intestinal stomas in patients operated due to colorectal cancer was significantly reduced. PMID:25960811

  14. Trend analysis of the 20 years time series of stratospheric ozone profiles observed by the GROMOS microwave radiometer at Bern

    NASA Astrophysics Data System (ADS)

    Moreira, L.; Hocke, K.; Eckert, E.; von Clarmann, T.; Kämpfer, N.

    2015-06-01

    The ozone radiometer GROMOS (GROund-based Millimeterwave Ozone Spectrometer) performs continuous observations of stratospheric ozone profiles since 1994 above Bern, Switzerland. GROMOS is part of the Network for the Detection of Atmospheric Composition Change (NDACC). From November 1994 to October 2011, the ozone line spectra were measured by a filter bench (FB). In July 2009, a Fast-Fourier-Transform spectrometer (FFTS) has been added as backend to GROMOS. The new FFTS and the original FB measured in parallel for over two years. The ozone profiles retrieved separately from the ozone line spectra of FB and FFTS agree within 5 % at pressure levels from 30 to 0.5 hPa, from October 2009 to August 2011. A careful harmonisation of both time series has been carried out by taking the FFTS as the reference instrument for the FB. This enables us to assess the long-term trend derived from more than 20 years of stratospheric ozone observations at Bern. The trend analysis has been performed by using a robust multilinear parametric trend model which includes a linear term, the solar variability, the El Niño-Southern Oscillation (ENSO) index, the quasi-biennial oscillation (QBO), the annual and semi-annual oscillation and several harmonics with period lengths between 3 and 24 months. Over the last years, some experimental and modelling trend studies have shown that the stratospheric ozone trend is levelling off or even turning positive. With our observed ozone profiles, we are able to support this statement by reporting a statistically significant trend of +3.14 % decade-1 at 4.36 hPa, covering the period from January 1997 to January 2015, above Bern. Additionally, we have estimated a negative trend over this period of -3.94 % decade-1 at 0.2 hPa.

  15. Determinants of Aortic Root Dilatation and Reference Values Among Young Adults Over a 20-Year Period: Coronary Artery Risk Development in Young Adults Study.

    PubMed

    Teixido-Tura, Gisela; Almeida, Andre L C; Choi, Eui-Young; Gjesdal, Ola; Jacobs, David R; Dietz, Harry C; Liu, Kiang; Sidney, Stephen; Lewis, Cora E; Garcia-Dorado, David; Evangelista, Artur; Gidding, Samuel; Lima, João A C

    2015-07-01

    Aortic size increases with age, but factors related to such dilatation in healthy young adult population have not been studied. We aim to evaluate changes in aortic dimensions and its principal correlates among young adults over a 20-year time period. Reference values for aortic dimensions in young adults by echocardiography are also provided. Healthy Coronary Artery Risk Development in Young Adults (CARDIA) study participants aged 23 to 35 years in 1990-1991 (n=3051) were included after excluding 18 individuals with significant valvular dysfunction. Aortic root diameter (ARD) by M-mode echocardiography at year-5 (43.7% men; age, 30.2 ± 3.6 years) and year-25 CARDIA exams was obtained. Univariable and multivariable analyses were performed to assess associations of ARD with clinical data at years-5 and -25. ARD from year-5 was used to establish reference values of ARD in healthy young adults. ARD at year-25 was greater in men (33.3 ± 3.7 versus 28.7 ± 3.4 mm; P<0.001) and in whites (30.9 ± 4.3 versus 30.5 ± 4.1 mm; P=0.006). On multivariable analysis, ARD at year-25 was positively correlated with male sex, white ethnicity, age, height, weight, 20-year gain in weight, active smoking at baseline, and 20-year increase in diastolic, systolic, and mean arterial pressure. A figure showing the estimated 95th percentile of ARD by age and body surface area stratified by race and sex is provided. This study demonstrates that smoking, blood pressure, and increase in body weight are the main modifiable correlates of aortic root dilation during young adulthood. Our study also provides reference values for ARD in young adults.

  16. Recurrent carcinoma of the head and neck: treatment strategies and survival analysis in a 20-year period.

    PubMed

    Eckardt, A; Barth, E L; Kokemueller, H; Wegener, G

    2004-04-01

    Following clinical diagnosis of a recurrent tumor, curative treatment is seldom available. Depending on the size of the recurrent tumor and the patient's general health condition extensive surgical resections and reconstructions are avoided in favor of non-surgical palliative intended treatment modalities. According to the literature location of the tumor, tumor size, as well as R-1- and R-2-resection rates are the most frequent reasons for the development of recurrent tumors. In a retrospective evaluation a population of 1000 patients who were treated for a primary head and neck cancer during the period from 1979 to 1996 were analysed descriptively. Survival probabilities of patients with recurrent tumors were calculated according to the product-limit method by Kaplan-Meier, different treatment concepts were compared and analysed with the log-rank test for significant differences. The largest proportion of primary tumors involved the floor of mouth ( n = 369, 36.9%). A total of 198 patients (19.8%) developed a recurrent cancer; 79.8% of patients experienced a recurrent cancer within two years following primary treatment. Within the group of T1/T2 tumors the incidence of recurrent tumors was 28.9%, whereas the incidence in the T3/T4 group was 44.6%. Tumor infiltration of the resection margins was detected in 12.9%. In line with the literature, tumor infiltration of the resection margins is a relevant prognostic factor, therefore intraoperative frozen section must be recommended. Treatment with curative intention, in particular extensive surgical resections, is seldom possible, and requires always a very intensive discussion with the patient.

  17. Trend analysis of the 20-year time series of stratospheric ozone profiles observed by the GROMOS microwave radiometer at Bern

    NASA Astrophysics Data System (ADS)

    Moreira, L.; Hocke, K.; Eckert, E.; von Clarmann, T.; Kämpfer, N.

    2015-10-01

    The ozone radiometer GROMOS (GROund-based Millimeter-wave Ozone Spectrometer) has been performing continuous observations of stratospheric ozone profiles since 1994 above Bern, Switzerland (46.95° N, 7.44° E, 577 m). GROMOS is part of the Network for the Detection of Atmospheric Composition Change (NDACC). From November 1994 to October 2011, the ozone line spectra were measured by a filter bench (FB). In July 2009, a fast Fourier transform spectrometer (FFTS) was added as a back end to GROMOS. The new FFTS and the original FB measured in parallel for over 2 years. The ozone profiles retrieved separately from the ozone line spectra of FB and FFTS agree within 5 % at pressure levels from 30 to 0.5 hPa, from October 2009 to August 2011. A careful harmonisation of both time series has been carried out by taking the FFTS as the reference instrument for the FB. This enables us to assess the long-term trend derived from stratospheric ozone observations at Bern. The trend analysis was performed by using a robust multilinear parametric trend model which includes a linear term, the solar variability, the El Niño-Southern Oscillation (ENSO) index, the quasi-biennial oscillation (QBO), the annual and semi-annual oscillation and several harmonics with period lengths between 3 and 24 months. Over the last years, some experimental and modelling trend studies have shown that the stratospheric ozone trend is levelling off or even turning positive. With our observed ozone profiles, we are able to support this statement by reporting a statistically significant trend of +3.14 % decade-1 at 4.36 hPa (37.76 km), covering the period from January 1997 to January 2015, above Bern. Additionally, we have estimated a negative trend over this period of -3.94 % decade-1 at 0.2 hPa (59 km).

  18. Yearbook 1988. IWGIA: 20 Years.

    ERIC Educational Resources Information Center

    Gray, Andrew

    The theme of this yearbook is the work of the International Work Group for Indigenous Affairs (IWGIA) during the 20 years of its existence and the enormous growth of the indigenous movement in that time. Section 1 traces IWGIA's history and includes the annual report for 1988. Section 2 is a global view of the main events in the indigenous world…

  19. Does Cancer Literature Reflect Multidisciplinary Practice? A Systematic Review of Oncology Studies in the Medical Literature Over a 20-Year Period

    SciTech Connect

    Holliday, Emma B.; Ahmed, Awad A.; Yoo, Stella K.; Jagsi, Reshma; Hoffman, Karen E.

    2015-07-15

    Purpose: Quality cancer care is best delivered through a multidisciplinary approach requiring awareness of current evidence for all oncologic specialties. The highest impact journals often disseminate such information, so the distribution and characteristics of oncology studies by primary intervention (local therapies, systemic therapies, and targeted agents) were evaluated in 10 high-impact journals over a 20-year period. Methods and Materials: Articles published in 1994, 2004, and 2014 in New England Journal of Medicine, Lancet, Journal of the American Medical Association, Lancet Oncology, Journal of Clinical Oncology, Annals of Oncology, Radiotherapy and Oncology, International Journal of Radiation Oncology, Biology, Physics, Annals of Surgical Oncology, and European Journal of Surgical Oncology were identified. Included studies were prospectively conducted and evaluated a therapeutic intervention. Results: A total of 960 studies were included: 240 (25%) investigated local therapies, 551 (57.4%) investigated systemic therapies, and 169 (17.6%) investigated targeted therapies. More local therapy trials (n=185 [77.1%]) evaluated definitive, primary treatment than systemic (n=178 [32.3%]) or targeted therapy trials (n=38 [22.5%]; P<.001). Local therapy trials (n=16 [6.7%]) also had significantly lower rates of industry funding than systemic (n=207 [37.6%]) and targeted therapy trials (n=129 [76.3%]; P<.001). Targeted therapy trials represented 5 (2%), 38 (10.2%), and 126 (38%) of those published in 1994, 2004, and 2014, respectively (P<.001), and industry-funded 48 (18.9%), 122 (32.6%), and 182 (54.8%) trials, respectively (P<.001). Compared to publication of systemic therapy trial articles, articles investigating local therapy (odds ratio: 0.025 [95% confidence interval: 0.012-0.048]; P<.001) were less likely to be found in high-impact general medical journals. Conclusions: Fewer studies evaluating local therapies, such as surgery and radiation, are published in

  20. Anagrelide: 20 years later.

    PubMed

    Emadi, Ashkan; Spivak, Jerry L

    2009-01-01

    Thrombocytosis is a common feature of chronic myeloproliferative disorders (MPD) and may be asymptomatic or associated with transient microvascular vaso-occlusive symptoms or large vessel arterial or venous thrombosis. Failure of either the hematocrit or the platelet count to correlate with thrombotic events is a peculiar conundrum of the MPDs. Asymptomatic thrombocytosis in young MPD patients with no cardiovascular risk factors does not require treatment. It is also undisputed that lowering the platelet count reduces the incidence of microvascular events in MPD patients. At the same time, no study to date has demonstrated that platelet count reduction prolongs survival in MPD patients. Agents such as hydroxyurea, busulfan, IFN-alpha and anagrelide, have been used to reduce an elevated platelet count and decrease thrombohemorrhagic events in at-risk patients with thrombocytosis associated with an MPD. When treatment is required, it makes sense to use drugs that are not myelotoxic or mutagenic. Based on the Primary Thrombocythaemia 1 study, hydroxyurea is the treatment of choice for thrombocytosis-associated transient ischemic attacks. However, hydroxyurea does not prevent venous thrombosis, is not more effective in preventing arterial thrombosis than anagrelide and its long-term safety is not established. Therefore, unless curative therapy is planned, one should use the least myelotoxic agent when platelet count reduction is required. In this regard, anagrelide can be considered a first-line drug. With regard to long-term safety of anagrelide, the EMEA has required close monitoring of the safety points identified in future Periodic Safety Update Reports and in a Post Authorisation Safety Study in the EU, which will focus especially on cardiovascular events and acute leukemia. In this article, we review anagrelide pharmacology, the physiology of thrombopoiesis, the differential diagnosis of thrombocytosis and the management of patients with an elevated platelet

  1. Atypical Central Neurocytoma with Recurrent Spinal Dissemination over a Period of 20 Years: A Case Report and Review of the Literature.

    PubMed

    Juratli, Tareq A; Geiger, Kathrin; Leimert, Mario; Schackert, Gabriele; Kirsch, Matthias

    2013-01-01

    We present an unusual case of a late recurrent central neurocytoma that was rediagnosed as an ependymoma and neurocytoma in accordance with changes in histological classifications. Case Description. A 56-year-old male teacher presented with incomplete transverse syndrome due to several intradural extramedullary tumors at the level of lumbar vertebrae 1-3. The histological diagnosis at the time was atypical ependymoma. One year later, two additional tumors were removed at the L5-S1 vertebral level. For 12 years, the patient remained tumor free on followup. Fourteen years after the initial diagnosis, the patient presented with thoracic paresthesias due to two new extramedullary tumors in the C7-T1 and the T8-T9 vertebral levels. After complete removal of the tumors, a radiological survey revealed an intracranial lesion in the third ventricle. Five months later, an additional lesion recurrence was removed surgically. The most recent histological diagnosis revealed an atypical central neurocytoma. In retrospect, the previous tumors were reclassified as neurocytoma according to the additional immunohistochemistry evidence. Discussion. There is no standard adjuvant treatment regimen for atypical neurocytoma; therefore, the patient is currently under close followup. Modern histopathological diagnosis is essential in these cases. Potential routes for dissemination of the tumor should be considered upon first recurrence.

  2. Celebrating 20 Years of Hubble

    NASA Video Gallery

    NASA's Hubble Space Telescope began a remarkable journey of discovery on April 24, 1990. After 20 years in space, the observatory has shown humanity more of the universe than ever before. With the ...

  3. SeaWiFS technical report series. Volume 17: Ocean color in the 21st century. A strategy for a 20-year time series

    NASA Technical Reports Server (NTRS)

    Abbott, Mark R.; Brown, Otis B.; Evans, Robert H.; Gordon, Howard R.; Carder, Kendall L.; Mueller-Karger, Frank E.; Esaias, Wayne E.; Hooker, Stanford B.; Firestone, Elaine R.

    1994-01-01

    Beginning with the upcoming launch of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), there should be almost continuous measurements of ocean color for nearly 20 years if all of the presently planned national and international missions are implemented. This data set will present a unique opportunity to understand the coupling of physical and biological processes in the world ocean. The presence of multiple ocean color sensors will allow the eventual development of an ocean color observing system that is both cost effective and scientifically based. This report discusses the issues involved and makes recommendations intended to ensure the maximum scientific return from this unique set of planned ocean color missions. An executive summary is included with this document which briefly discusses the primary issues and suggested actions to be considered.

  4. Oral biopsy turnaround time: 20-year experience of the Department of Oral Pathology, Oral Medicine and Periodontology, Faculty of Dentistry, University of Malaya.

    PubMed

    Siar, C H; Tan, B H

    2000-12-01

    The turnaround time (TAT) for oral biopsies received for histological examination by the Department of Oral Pathology, Oral Medicine and Periodontology, Faculty of Dentistry, University of Malaya, for the years 1978, 1988 and 1998 was evaluated. For the three years studied, TATs for 61, 233 and 463 specimens were retrospectively analysed. Testing intervals, that is, from the dates the surgeons procured the specimens, the laboratories accessioned them and until the pathologists signed off the diagnoses, were used to calculate TAT. The performance level of the respective pathologists, the growth of tissue diagnostic services and the possible variables that influence TAT were also evaluated. As prompt diagnosis means prompt treatment, which in turn has a bearing on prognosis, the TAT pertinent to oral malignant tumors was emphasized. The mean TAT, its mode and median fell significantly in 1998 compared with the previous 2 years; it was lower for soft tissue than for hard tissue specimens, and lower for malignant, than for non-malignant specimens. The progression of tissue diagnostic services is up to a satisfactory level, as 88.89 % of biopsies could render diagnoses within a fair period of time in 1998.

  5. 43 CFR 10010.45 - Time periods.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Time periods. 10010.45 Section 10010.45... Environmental Impact Statements § 10010.45 Time periods. (a) The minimum review period for a draft EIS will be... proposed reductions in time periods or any extensions of time periods proposed by those agencies....

  6. 43 CFR 10010.45 - Time periods.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Time periods. 10010.45 Section 10010.45... Environmental Impact Statements § 10010.45 Time periods. (a) The minimum review period for a draft EIS will be... proposed reductions in time periods or any extensions of time periods proposed by those agencies....

  7. 43 CFR 10010.45 - Time periods.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Time periods. 10010.45 Section 10010.45... Environmental Impact Statements § 10010.45 Time periods. (a) The minimum review period for a draft EIS will be... proposed reductions in time periods or any extensions of time periods proposed by those agencies....

  8. 43 CFR 10010.45 - Time periods.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Time periods. 10010.45 Section 10010.45... Environmental Impact Statements § 10010.45 Time periods. (a) The minimum review period for a draft EIS will be... proposed reductions in time periods or any extensions of time periods proposed by those agencies....

  9. Turkey Revisited: Reflections on Turkish Society and Culture after 20 Years of Absence

    DTIC Science & Technology

    1988-12-01

    0 o TURKEY REVISITED: REFLECTIONS ON TURKISH SOCIETY AND CULTURE AFTER 20 YEARS OF ABSENCE Graham E, Fuller December 1988 14 LECTEIff P-7513 mens... culture . He read dozens of Turkish novels of the time and became acquainted with many of their authors. As a result, he wrote a book- length analysis of the...SOCIETY AND CULTURE AFTER 20 YEARS OF ABSENCE Graham E. Fuller There is much merit in abandoning an intellectual discipline for lengthy periods of

  10. Time domain period determination techniques

    NASA Technical Reports Server (NTRS)

    Stellingwerf, R. F.

    1980-01-01

    Two simple period determination schemes are discussed. They are well suited to problems involving non-sinusoidal periodic phenomena sampled at a few irregularly spaced points. Statistical properties are discussed. The techniques are applied to the double mode Cepheids BK Cen and TU Cas as test cases.

  11. Time domain period determination techniques

    NASA Astrophysics Data System (ADS)

    Stellingwerf, R. F.

    1980-05-01

    Two simple period determination schemes are discussed. They are well suited to problems involving non-sinusoidal periodic phenomena sampled at a few irregularly spaced points. Statistical properties are discussed. The techniques are applied to the double mode Cepheids BK Cen and TU Cas as test cases.

  12. [Vaccination against hepatitis B. Impact of vaccination programmes after 20 years of use in Spain. Is it time for a change?].

    PubMed

    Arístegui Fernández, Javier; Díez-Domingo, Javier; Marés Bermúdez, Josep; Martinón Torres, Federico

    2015-02-01

    The highest incidence rate of hepatitis B (HB) in Spain is detected in adults between 20 and 54 years old, whereas the incidence in children under 1 year old is almost nil. The low prevalence of HB in children under 1 year is mainly due to the success of gestational screening strategies for the detection of HBsAg(+) in pregnant women, and vaccination campaigns during childhood. Currently, in Spain, the last dose of the HB included in the national childhood immunization program is administered at 6 months of age, although some studies show that delaying the age of the administration of the last dose of HB vaccine and increasing the time between doses, may improve immune memory by offering greater protection against this virus in the adulthood. In this article, the impact of HB vaccination in Spain is reviewed, and other potential vaccination strategies in our environment are discussed, such as extending the interval between doses, and administering the last dose in the second year of life, adapting the valid strategy in Spain to the current epidemiological context in order to reduce the prevalence of HB in adulthood.

  13. Hubble: 20 Years of Discovery

    NASA Video Gallery

    Hubble's discoveries have revolutionized nearly all areas of current astronomical research from planetary science to cosmology. Actor and writer Brent Spiner narrates a visual journey back in time ...

  14. 24 CFR 58.21 - Time periods.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Time periods. 58.21 Section 58.21...: Environmental Review Procedures § 58.21 Time periods. All time periods in this part shall be counted in calendar days. The first day of a time period begins at 12:01 a.m. local time on the day following...

  15. 24 CFR 58.21 - Time periods.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 1 2014-04-01 2014-04-01 false Time periods. 58.21 Section 58.21...: Environmental Review Procedures § 58.21 Time periods. All time periods in this part shall be counted in calendar days. The first day of a time period begins at 12:01 a.m. local time on the day following...

  16. 24 CFR 58.21 - Time periods.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 1 2013-04-01 2013-04-01 false Time periods. 58.21 Section 58.21...: Environmental Review Procedures § 58.21 Time periods. All time periods in this part shall be counted in calendar days. The first day of a time period begins at 12:01 a.m. local time on the day following...

  17. 24 CFR 58.21 - Time periods.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 1 2012-04-01 2012-04-01 false Time periods. 58.21 Section 58.21...: Environmental Review Procedures § 58.21 Time periods. All time periods in this part shall be counted in calendar days. The first day of a time period begins at 12:01 a.m. local time on the day following...

  18. 24 CFR 58.21 - Time periods.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 1 2011-04-01 2011-04-01 false Time periods. 58.21 Section 58.21...: Environmental Review Procedures § 58.21 Time periods. All time periods in this part shall be counted in calendar days. The first day of a time period begins at 12:01 a.m. local time on the day following...

  19. Infrared Variability and Time Lags for Periodic Quasars

    NASA Astrophysics Data System (ADS)

    Jun, Hyunsung David; Stern, Daniel; Graham, Matthew J.; Djorgovski, Stanislav G.; Mainzer, Amy; Cutri, Roc M.; Drake, Andrew J.; Mahabal, Ashish A.

    2017-01-01

    The optical light curve of the quasar PG 1302-102 at z=0.278 shows a 5.2 year periodic signal, detectable over a period of 20 years. The most plausible mechanisms involve a binary supermassive black hole system with a sub-pc separation, where they will likely merge within ~10^5 years due to gravitational wave emission alone. Here, we report the infrared time lags for PG 1302-102 from WISE and Akari missions. We confirm that the periodic behavior reported in the optical light curve is reproduced at infrared, with best-fit 3.4 and 4.6 micron time lags of (2219 ± 153, 2408 ± 148) days for a near face-on orientation of the torus, or (4103 ± 153, 4292 ± 148) days for an inclined system with relativistic Doppler boosting in effect. The periodicity in the infrared light curves and the time lag to the optical support that a source within the accretion disk is responsible for the optical variability of PG 1302-102, echoed at the farther out dusty regions ~1.1-1.3 pc away. We briefly mention ongoing works to constrain the infrared variability and time lags for all the identified periodic quasars, and to relate the quantities to physical origins.

  20. 20 Years Later: How One Flagship Has Changed

    ERIC Educational Resources Information Center

    Blumenstyk, Goldie

    2008-01-01

    This article examines how the University of Kansas has changed in 20 years. Twenty years ago, annual operating expenses for the University of Kansas campus here were $204-million. Today the institution spends more than triple that, even though its enrollment, 26,000, is almost exactly the same. During the same period, tuition and fees for in-state…

  1. Rotorcraft Smoothing Via Linear Time Periodic Methods

    DTIC Science & Technology

    2007-07-01

    Optimal Control Methodology for Rotor Vibration Smoothing . . 30 vii Page IV. Mathematic Foundations of Linear Time Periodic Systems . . . . 33 4.1 The...62 6.3 The Maximum Likelihood Estimator . . . . . . . . . . . 63 6.4 The Cramer-Rao Inequality . . . . . . . . . . . . . . . . 66 6.4.1 Statistical ...adjustments for vibration reduction. 2.2.2.4 1980’s to late 1990’s. Rotor vibrational reduction methods during the 1980’s began to adopt a mathematical

  2. NCCN: 20 Years of Improving Patients' Lives.

    PubMed

    Carlson, Robert W

    2015-05-01

    In his Keynote Address at the NCCN 20th Annual Conference, Robert W. Carlson, MD, reflected on the achievements of NCCN and described how the organization will continue to grow under his leadership. Recognizing that the founding of NCCN was by a group of visionary leaders who came together 20 years ago to assure access of patients to high-quality cancer care, Dr. Carlson said "All our efforts within NCCN are focused on improving the quality, effectiveness, and efficiency of patient care, so that our patients can live better lives."

  3. Human psychoneuroimmunology: 20 years of discovery.

    PubMed

    Irwin, Michael R

    2008-02-01

    An important component of psychoneuroimmunology research is to reveal the myriad ways that behaviors and health are inter-related, with a focus on the immunological mechanisms that underlie these interactions. Research in human psychoneuroimmunology has shown that immunoregulatory processes are an integral part of a complex network of adaptive responses. As such, this review provides a perspective from our laboratory over the last 20 years to define the inter-relationships between behavior and immunity; to identify the hypothalamic pituitary adrenal (HPA) and autonomic mechanisms that link the central nervous system and immune responses; to examine the clinical implications of immune alterations during depression or life stress on inflammatory and infectious disease risk; and to explore the reciprocal role of immune mediators on behavior in humans.

  4. Sources of happiness and stress for college students: a replication and comparison over 20 years.

    PubMed

    Staats, Sara; Cosmar, David; Kaffenberger, Joshua

    2007-12-01

    The advancement of positive psychology is dependent upon measures of happiness, both globally and in specific contexts. Data are presented on two measures of sources of college students' happiness from two samples. Testing of the two cohorts (Ns=258, 68) was separated by 20 years. Measures for both samples had acceptable psychometric properties. There was an increase in college students' self-reported happiness across the 20-year period in the rankings of different sources of college happiness and general happiness. In a second study, a different group of students (N= 176) were given a list and asked to select the most important uplifts and hassles in their lives. In general, mean scores on affect measures were relatively stable across time, but transportation hassles were reported as a new source of negative affect in the present study.

  5. Intranasal and transantral ethmoidectomy: a 20-year experience.

    PubMed

    Friedman, W H; Katsantonis, G P

    1990-04-01

    Ethmoidectomy is an operation that has engendered controversy concerning the best route of surgical access. The purpose of this study was to present the results of the authors' experience in more than 1300 intranasal sphenoethmoidectomies and transantral sphenoethmoidectomies performed over a 20-year period. The authors contend that the most effective ethmoidectomy is the most complete ethmoidectomy and have previously presented a case for ethmoid marsupialization. Polyp recurrence rates of less than 20% and a major complication rate of less than 1% were reported in this study.

  6. [Surgical treatment of esophageal achalasia--20 years experience].

    PubMed

    Yaramov, N; Sokolov, M; Angelov, K; Toshev, S; Petrov, B

    2009-01-01

    Achalasia comes from a Greek word that means "failure to relax." Cardiospasm and achalasia refer to the same condition. This report addresses esophageal achalasia--its history, diagnosis, pathophysiology, and treatment options. We report our experience in treating this disorder surgically using modified Heller myotomy combined or not with partial gastric fundoplication. 47 patients with achalasia surgically operated in 20-years period are reported by authors. These features make it reasonable to reasses the relative indications for surgery and nonsurgical therapy in achalasia of the esophagus.

  7. Deferiprone‐induced agranulocytosis: 20 years of clinical observations

    PubMed Central

    Uetrecht, Jack; Galanello, Renzo; Connelly, John; Rozova, Anna; Spino, Michael; Palmblad, Jan

    2016-01-01

    Use of the iron chelator deferiprone for treatment of iron overload in thalassemia patients is associated with concerns over agranulocytosis, which requires weekly absolute neutrophil counts (ANC). Here, we analyze all episodes of agranulocytosis (n = 161) and neutropenia (n = 250) during deferiprone use in clinical trials (CT) and postmarketing surveillance programs (PMSP). Rates of agranulocytosis and neutropenia in CT were 1.5% and 5.5%, respectively. Of the agranulocytosis cases, 61% occurred during the first 6 months of therapy and 78% during the first year. These events appeared to be independent of dose, and occurred three times more often in females than males. Their duration was not significantly shortened by use of G‐CSF. No patient with baseline neutropenia (n = 12) developed agranulocytosis during treatment, which raises questions about the validity of prior neutropenia as a contraindication to use. Only 1/7 novel neutropenia cases in CT progressed to agranulocytosis with continued treatment, indicating that neutropenia does not necessarily lead to agranulocytosis. The agranulocytosis fatality rate was 0% in CT and 15/143 (11%) in PMSP. Rechallenge with deferiprone produced agranulocytosis in 75% of patients in whom the event had already occurred, and in 10% with previous neutropenia. Weekly ANC monitoring allows early detection and interruption of therapy, but does not prevent agranulocytosis from occurring. Its relevance appears to decrease after the first year of therapy, when agranulocytosis occurs less often. Based upon analysis of data collected over the past 20 years, it appears that patient education may be the key to minimizing agranulocytosis‐associated risks during deferiprone therapy. Am. J. Hematol. 91:1026–1031, 2016. © 2016 The Authors. American Journal of Hematology Published by Wiley Periodicals, Inc. PMID:27415835

  8. 43 CFR 45.3 - How are time periods computed?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false How are time periods computed? 45.3... IN FERC HYDROPOWER LICENSES General Provisions § 45.3 How are time periods computed? (a) General. Time periods are computed as follows: (1) The day of the act or event from which the period begins...

  9. RT Remembrance: The First 20 Years.

    ERIC Educational Resources Information Center

    Stahl, Norman A.; Fisher, Peter J. L.

    1992-01-01

    Provides a detailed analysis of the first 20 volumes of "The Reading Teacher," asking whether the journal mirrored trends in the field or provided a window on its future. Concludes that the journal mirrored the times. (MG)

  10. Time periodic solution to the compressible Euler equations with damping in a periodic domain

    NASA Astrophysics Data System (ADS)

    Tan, Zhong; Xu, Qiuju; Wang, Huaqiao

    2016-07-01

    In this paper, we consider the existence and uniqueness of a time periodic solution to the three-dimensional compressible damped Euler equations in a periodic domain. By adapting a regularized approximation scheme and applying the topological degree theory, we establish the existence of the time periodic solution under some smallness and structure assumptions imposed on a time periodic force. And based on energy estimates, the uniqueness of the periodic solution is proved.

  11. [Evaluation of 20 years' experience of enuresis in children].

    PubMed

    Averous, M; Lopez, C

    1997-06-01

    The clinical and urodynamic approach to enuretic children over a period of more than 20 years has allowed the authors to develop a multifactorial pathophysiological concept of this disorder. The main factors involved are psychological, familial, genetic, vesical, due to bladder immaturity, hormonal, due to a defect of nocturnal ADH secretion, hygiene and dietary habits, etc. The sleep factor is predominant in the majority of cases. Although nocturnal enuresis is apparently isolated in many cases, it is often associated with a state of bladder immaturity, sometimes latent during the day, but occurring at night with episodes of detrusor hyperactivity, occurring during various phases of sleep. In practice, the recognition, in children, of these factors, some of which require specific treatments, implies a management combining several of these therapeutic modalities.

  12. 7 CFR 1.603 - How are time periods computed?

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 1 2013-01-01 2013-01-01 false How are time periods computed? 1.603 Section 1.603 Agriculture Office of the Secretary of Agriculture ADMINISTRATIVE REGULATIONS Conditions in FERC Hydropower Licenses General Provisions § 1.603 How are time periods computed? (a) General. Time periods are...

  13. 7 CFR 1.603 - How are time periods computed?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 1 2012-01-01 2012-01-01 false How are time periods computed? 1.603 Section 1.603 Agriculture Office of the Secretary of Agriculture ADMINISTRATIVE REGULATIONS Conditions in FERC Hydropower Licenses General Provisions § 1.603 How are time periods computed? (a) General. Time periods are...

  14. 7 CFR 1.603 - How are time periods computed?

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 1 2014-01-01 2014-01-01 false How are time periods computed? 1.603 Section 1.603 Agriculture Office of the Secretary of Agriculture ADMINISTRATIVE REGULATIONS Conditions in FERC Hydropower Licenses General Provisions § 1.603 How are time periods computed? (a) General. Time periods are...

  15. 7 CFR 1.603 - How are time periods computed?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 1 2011-01-01 2011-01-01 false How are time periods computed? 1.603 Section 1.603 Agriculture Office of the Secretary of Agriculture ADMINISTRATIVE REGULATIONS Conditions in FERC Hydropower Licenses General Provisions § 1.603 How are time periods computed? (a) General. Time periods are...

  16. 50 CFR 221.3 - How are time periods computed?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false How are time periods computed? 221.3 Section 221.3 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC... Provisions § 221.3 How are time periods computed? (a) General. Time periods are computed as follows: (1)...

  17. 7 CFR 1.603 - How are time periods computed?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false How are time periods computed? 1.603 Section 1.603 Agriculture Office of the Secretary of Agriculture ADMINISTRATIVE REGULATIONS Conditions in FERC Hydropower Licenses General Provisions § 1.603 How are time periods computed? (a) General. Time periods are...

  18. Global satellite composites - 20 years of evolution

    NASA Astrophysics Data System (ADS)

    Kohrs, Richard A.; Lazzara, Matthew A.; Robaidek, Jerrold O.; Santek, David A.; Knuth, Shelley L.

    2014-01-01

    For two decades, the University of Wisconsin Space Science and Engineering Center (SSEC) and the Antarctic Meteorological Research Center (AMRC) have been creating global, regional and hemispheric satellite composites. These composites have proven useful in research, operational forecasting, commercial applications and educational outreach. Using the Man computer Interactive Data System (McIDAS) software developed at SSEC, infrared window composites were created by combining Geostationary Operational Environmental Satellite (GOES), and polar orbiting data from the SSEC Data Center and polar data acquired at McMurdo and Palmer stations, Antarctica. Increased computer processing speed has allowed for more advanced algorithms to address the decision making process for co-located pixels. The algorithms have evolved from a simplistic maximum brightness temperature to those that account for distance from the sub-satellite point, parallax displacement, pixel time and resolution. The composites are the state-of-the-art means for merging/mosaicking satellite imagery.

  19. Detecting unstable periodic orbits from transient chaotic time series

    PubMed

    Dhamala; Lai; Kostelich

    2000-06-01

    We address the detection of unstable periodic orbits from experimentally measured transient chaotic time series. In particular, we examine recurrence times of trajectories in the vector space reconstructed from an ensemble of such time series. Numerical experiments demonstrate that this strategy can yield periodic orbits of low periods even when noise is present. We analyze the probability of finding periodic orbits from transient chaotic time series and derive a scaling law for this probability. The scaling law implies that unstable periodic orbits of high periods are practically undetectable from transient chaos.

  20. Radium in man - 20 years later

    SciTech Connect

    Maletskos, C.J.

    1994-12-31

    In 1940, there was a need to set a standard for internal exposure to radium for the instrument industry that required luminous characters painted with radium paint. A committee was convened to review the existing information on the health effects of internal radium. Twenty-seven persons had been studied, seven with burdens of 0.5 {mu}g or less with no health effects and twenty with burdens of 1.2 {mu}g or more with health effects. The radium burden dividing the two groups was assumed at 1 {mu}g (an implied threshold), a safety factor of 10 was applied, and the internal radium standard was set at 0.1 {mu}g, a value that still stands today. Over the next five or six decades, about 2000 subjects were investigated, including many measurements on almost all the subjects. In the intervening years, several analyses of the data, available at each particular time, have been made with radical differences in interpretation.

  1. My first 20 years in neuroscience.

    PubMed

    Maisky, V A

    2011-01-01

    Intriguing facts were obtained in the first electrophysiological investigations (1964) that the action potentials (AP) produced by direct depolarization of the cell membrane in different species of mollusks showed specific relations to changes in external ionic composition. In Helix neurons, the generation of AP was well maintained in sodium-free solutions with high calcium or barium content. The amplitude of the spike overshoot in the case was linearly related to the logarithm of calcium concentration. It is interesting that increase in external calcium ions decreased the ionic conductance of the resting membrane (R0) also in linear relation to the logarithm of Ca2+ or Ba2+ concentration. It was found for the first time (1965) that addition of Ba2+ to the external solution produced in the neurons well-developed prolonged (protracted) APs in all cases. However, the excitability of Planorbis and Limnea neurons was rapidly (during 3 min) reversibly depressed in sodium-free solutions. We found that, after injections of horse radish peroxidase (HRP) in the spinal cord of cats, the enzyme was transported retrogradely to brain stem neurons in the bulbar medial reticular formation, the vestibular complex, and the red nucleus. We obtained (1975) intriguing facts in our investigations: we recorded the labeled neurons in the locus coeruleus and subcoeruleus, as well as in the paraventricular hypothalamic nucleus. The existence of straight pathways from hypothalamus to the spinal cord has not been demonstrated earlier. The next step of our study was to determine the corresponding spinal funiculi where descending fibers (from various brain stem cell groups) are located. Indeed, in our pioneer studies (1977), we found that the fibers from the hypothalamus, which descend throughout the spinal cord, are located mainly in the lateral funiculus, ipsilaterally.

  2. Probe microphone measurements: 20 years of progress.

    PubMed

    Mueller, H G

    2001-06-01

    Probe-microphone testing was conducted in the laboratory as early as the 1940s (e.g., the classic work of Wiener and Ross, reported in 1946), however, it was not until the late 1970s that a "dispenser friendly" system was available for testing hearing aids in the real ear. In this case, the term "dispenser friendly," is used somewhat loosely. The 1970s equipment that I'm referring to was first described in a paper that was presented by Earl Harford, Ph.D. in September of 1979 at the International Ear Clinics' Symposium in Minneapolis. At this meeting, Earl reported on his clinical experiences of testing hearing aids in the real ear using a miniature (by 1979 standards) Knowles microphone. The microphone was coupled to an interfacing impedance matching system (developed by David Preves, Ph.D., who at the time worked at Starkey Laboratories) which could be used with existing hearing aid analyzer systems (see Harford, 1980 for review of this early work). Unlike today's probe tube microphone systems, this early method of clinical real-ear measurement involved putting the entire microphone (about 4mm by 5mm by 2mm) in the ear canal down by the eardrum of the patient. If you think cerumen is a problem with probe-mic measurements today, you should have seen the condition of this microphone after a day's work! While this early instrumentation was a bit cumbersome, we quickly learned the advantages that probe-microphone measures provided in the fitting of hearing aids. We frequently ran into calibration and equalization problems, not to mention a yelp or two from the patient, but the resulting information was worth the trouble. Help soon arrived. In the early 1980s, the first computerized probe-tube microphone system, the Rastronics CCI-10 (developed in Denmark by Steen Rasmussen), entered the U.S. market (Nielsen and Rasmussen, 1984). This system had a silicone tube attached to the microphone (the transmission of sound through this tube was part of the calibration process

  3. Contact time periods in immunological synapse

    NASA Astrophysics Data System (ADS)

    Bush, Daniel R.; Chattopadhyay, Amit K.

    2014-10-01

    This paper resolves the long standing debate as to the proper time scale <τ> of the onset of the immunological synapse bond, the noncovalent chemical bond defining the immune pathways involving T cells and antigen presenting cells. Results from our model calculations show <τ> to be of the order of seconds instead of minutes. Close to the linearly stable regime, we show that in between the two critical spatial thresholds defined by the integrin:ligand pair (Δ2˜ 40-45 nm) and the T-cell receptor TCR:peptide-major-histocompatibility-complex pMHC bond (Δ1˜ 14-15 nm), <τ> grows monotonically with increasing coreceptor bond length separation δ (= Δ2-Δ1˜ 26-30 nm) while <τ> decays with Δ1 for fixed Δ2. The nonuniversal δ-dependent power-law structure of the probability density function further explains why only the TCR:pMHC bond is a likely candidate to form a stable synapse.

  4. African Savanna-Forest Boundary Dynamics: A 20-Year Study.

    PubMed

    Cuni-Sanchez, Aida; White, Lee J T; Calders, Kim; Jeffery, Kathryn J; Abernethy, Katharine; Burt, Andrew; Disney, Mathias; Gilpin, Martin; Gomez-Dans, Jose L; Lewis, Simon L

    2016-01-01

    Recent studies show widespread encroachment of forest into savannas with important consequences for the global carbon cycle and land-atmosphere interactions. However, little research has focused on in situ measurements of the successional sequence of savanna to forest in Africa. Using long-term inventory plots we quantify changes in vegetation structure, above-ground biomass (AGB) and biodiversity of trees ≥10 cm diameter over 20 years for five vegetation types: savanna; colonising forest (F1), monodominant Okoume forest (F2); young Marantaceae forest (F3); and mixed Marantaceae forest (F4) in Lopé National Park, central Gabon, plus novel 3D terrestrial laser scanning (TLS) measurements to assess forest structure differences. Over 20 years no plot changed to a new stage in the putative succession, but F1 forests strongly moved towards the structure, AGB and diversity of F2 forests. Overall, savanna plots showed no detectable change in structure, AGB or diversity using this method, with zero trees ≥10 cm diameter in 1993 and 2013. F1 and F2 forests increased in AGB, mainly as a result of adding recruited stems (F1) and increased Basal Area (F2), whereas F3 and F4 forests did not change substantially in structure, AGB or diversity. Critically, the stability of the F3 stage implies that this stage may be maintained for long periods. Soil carbon was low, and did not show a successional gradient as for AGB and diversity. TLS vertical plant profiles showed distinctive differences amongst the vegetation types, indicating that this technique can improve ecological understanding. We highlight two points: (i) as forest colonises, changes in biodiversity are much slower than changes in forest structure or AGB; and (ii) all forest types store substantial quantities of carbon. Multi-decadal monitoring is likely to be required to assess the speed of transition between vegetation types.

  5. African Savanna-Forest Boundary Dynamics: A 20-Year Study

    PubMed Central

    Cuni-Sanchez, Aida; White, Lee J. T.; Calders, Kim; Jeffery, Kathryn J.; Abernethy, Katharine; Burt, Andrew; Disney, Mathias; Gilpin, Martin; Gomez-Dans, Jose L.; Lewis, Simon L.

    2016-01-01

    Recent studies show widespread encroachment of forest into savannas with important consequences for the global carbon cycle and land-atmosphere interactions. However, little research has focused on in situ measurements of the successional sequence of savanna to forest in Africa. Using long-term inventory plots we quantify changes in vegetation structure, above-ground biomass (AGB) and biodiversity of trees ≥10 cm diameter over 20 years for five vegetation types: savanna; colonising forest (F1), monodominant Okoume forest (F2); young Marantaceae forest (F3); and mixed Marantaceae forest (F4) in Lopé National Park, central Gabon, plus novel 3D terrestrial laser scanning (TLS) measurements to assess forest structure differences. Over 20 years no plot changed to a new stage in the putative succession, but F1 forests strongly moved towards the structure, AGB and diversity of F2 forests. Overall, savanna plots showed no detectable change in structure, AGB or diversity using this method, with zero trees ≥10 cm diameter in 1993 and 2013. F1 and F2 forests increased in AGB, mainly as a result of adding recruited stems (F1) and increased Basal Area (F2), whereas F3 and F4 forests did not change substantially in structure, AGB or diversity. Critically, the stability of the F3 stage implies that this stage may be maintained for long periods. Soil carbon was low, and did not show a successional gradient as for AGB and diversity. TLS vertical plant profiles showed distinctive differences amongst the vegetation types, indicating that this technique can improve ecological understanding. We highlight two points: (i) as forest colonises, changes in biodiversity are much slower than changes in forest structure or AGB; and (ii) all forest types store substantial quantities of carbon. Multi-decadal monitoring is likely to be required to assess the speed of transition between vegetation types. PMID:27336632

  6. Student Instruction Should Be Distributed over Long Time Periods

    ERIC Educational Resources Information Center

    Rohrer, Doug

    2015-01-01

    In many academic courses, students encounter a particular fact or concept many times over a period of a few weeks and then do not see it again during the remainder of the course. Are these brief instructional periods sufficient, or should the same amount of instruction be distributed over longer periods of time? This question was the focus of…

  7. Searching for periodicity in weighted time point series.

    NASA Astrophysics Data System (ADS)

    Jetsu, L.; Pelt, J.

    1996-09-01

    Consistent statistics for two methods of searching for periodicity in a series of weighted time points are formulated. An approach based on the bootstrap method to estimate the accuracy of detected periodicity is presented.

  8. A Longitudinal Examination of Career Expectations and Outcomes of Academically Talented Students 10 and 20 Years Post-High School Graduation

    ERIC Educational Resources Information Center

    Perrone, Kristin M.; Tschopp, Molly K.; Snyder, Erin R.; Boo, Jenelle N.; Hyatt, Claudine

    2010-01-01

    The purpose of this study was to examine career expectations and outcomes for individuals who were identified as academically talented high school students. Data for this study were collected at two different time periods: 10 years and 20 years after participants' high school graduation. A decade after graduation from high school, participants…

  9. Multicultural Counseling Competencies Research: A 20-Year Content Analysis

    ERIC Educational Resources Information Center

    Worthington, Roger L.; Soth-McNett, Angela M.; Moreno, Matthew V.

    2007-01-01

    The authors conducted a 20-year content analysis of the entire field of empirical research on the multicultural counseling competencies (D. W. Sue et al., 1982). They conducted an exhaustive search for empirical research articles using PsycINFO, as well as complete reviews of the past 20 years of several journals (e.g., Journal of Counseling…

  10. Mining approximate periodic pattern in hydrological time series

    NASA Astrophysics Data System (ADS)

    Zhu, Y. L.; Li, S. J.; Bao, N. N.; Wan, D. S.

    2012-04-01

    There is a lot of information about the hidden laws of nature evolution and the influences of human beings activities on the earth surface in long sequence of hydrological time series. Data mining technology can help find those hidden laws, such as flood frequency and abrupt change, which is useful for the decision support of hydrological prediction and flood control scheduling. The periodic nature of hydrological time series is important for trend forecasting of drought and flood and hydraulic engineering planning. In Hydrology, the full period analysis of hydrological time series has attracted a lot of attention, such as the discrete periodogram, simple partial wave method, Fourier analysis method, and maximum entropy spectral analysis method and wavelet analysis. In fact, the hydrological process is influenced both by deterministic factors and stochastic ones. For example, the tidal level is also affected by moon circling the Earth, in addition to the Earth revolution and its rotation. Hence, there is some kind of approximate period hidden in the hydrological time series, sometimes which is also called the cryptic period. Recently, partial period mining originated from the data mining domain can be a remedy for the traditional period analysis methods in hydrology, which has a loose request of the data integrity and continuity. They can find some partial period in the time series. This paper is focused on the partial period mining in the hydrological time series. Based on asynchronous periodic pattern and partial period mining with suffix tree, this paper proposes to mine multi-event asynchronous periodic pattern based on modified suffix tree representation and traversal, and invent a dynamic candidate period intervals adjusting method, which can avoids period omissions or waste of time and space. The experimental results on synthetic data and real water level data of the Yangtze River at Nanjing station indicate that this algorithm can discover hydrological

  11. Early excision and grafting of face and neck burns in patients over 20 years.

    PubMed

    Cole, Jana K; Engrav, Loren H; Heimbach, David M; Gibran, Nicole S; Costa, Beth A; Nakamura, Dana Y; Moore, Merilyn L; Blayney, Carolyn B; Hoover, Carolyn L

    2002-04-01

    Although excision and grafting of burns has become common and standard, many surgeons have been reluctant to excise and graft face burns. In fact, we could find photographic results at 1 year after grafting of only eight patients in the English literature. We began excision and grafting of face burns in 1979 and presented our first 16 patients in 1986 in this journal. With encouragement from Janzekovic and Jackson, we continued and have now used essentially the same procedure for more than 20 years in approximately 100 patients and, from this large series, are able to present outcomes. From January of 1979 to May of 1999, we performed excision and grafting on 91 patients with deep face burns. Data were recorded and 35-mm photographs were obtained throughout the 20-year period. We reviewed that database and the slide files of these patients. We found 45 patients with complete photographic sets including 1-year follow-up. Since, in our opinion, there is no useful, objective measure of appearance, we decided to simply publish all 45 sets of complete photographs, permitting the reader to subjectively form an opinion of the outcome of this procedure. The results are all shown as "full" face burns and two "partial" face burns. We continue to believe that early excision and grafting is indicated for face burns that will not heal within 3 weeks and that the procedure yields results that permit the burn victims to return to society and minimizes the time off work or out of school.

  12. Episodic Heavy Drinking and 20-Year Total Mortality Among Late-Life Moderate Drinkers

    PubMed Central

    Holahan, Charles J.; Brennan, Penny L.; Schutte, Kathleen K.; Holahan, Carole K.; Moos, Rudolf H.

    2014-01-01

    Background Analyses of moderate drinking have focused overwhelmingly on average consumption, which masks diverse underlying drinking patterns. This study examined the association between episodic heavy drinking and total mortality among moderate-drinking older adults. Methods At baseline, the sample was comprised of 446 adults aged 55 to 65: 74 moderate drinkers who engaged in episodic heavy drinking and 372 regular moderate drinkers. The database at baseline also included a broad set of sociodemographic, behavioral, and health status covariates. Death across a 20-year follow-up period was confirmed primarily by death certificate. Results In multiple logistic regression analyses, after adjusting for all covariates, as well as overall alcohol consumption, moderate drinkers who engaged in episodic heavy drinking had more than two times higher odds of 20-year mortality in comparison to regular moderate drinkers. Conclusions Among older moderate drinkers, those who engage in episodic heavy drinking show significantly increased total mortality risk compared to regular moderate drinkers. Episodic heavy drinking—even when average consumption remains moderate—is a significant public health concern. PMID:24588326

  13. 19 CFR 158.21a - Time period.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 2 2014-04-01 2014-04-01 false Time period. 158.21a Section 158.21a Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY... While in Customs Custody § 158.21a Time period. An abatement or refund of duties shall be made in...

  14. 19 CFR 158.21a - Time period.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 2 2013-04-01 2013-04-01 false Time period. 158.21a Section 158.21a Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY... While in Customs Custody § 158.21a Time period. An abatement or refund of duties shall be made in...

  15. 43 CFR 45.3 - How are time periods computed?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false How are time periods computed? 45.3 Section 45.3 Public Lands: Interior Office of the Secretary of the Interior CONDITIONS AND PRESCRIPTIONS IN FERC HYDROPOWER LICENSES General Provisions § 45.3 How are time periods computed? (a)...

  16. 43 CFR 45.3 - How are time periods computed?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true How are time periods computed? 45.3 Section 45.3 Public Lands: Interior Office of the Secretary of the Interior CONDITIONS AND PRESCRIPTIONS IN FERC HYDROPOWER LICENSES General Provisions § 45.3 How are time periods computed? (a) General....

  17. 43 CFR 45.3 - How are time periods computed?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false How are time periods computed? 45.3 Section 45.3 Public Lands: Interior Office of the Secretary of the Interior CONDITIONS AND PRESCRIPTIONS IN FERC HYDROPOWER LICENSES General Provisions § 45.3 How are time periods computed? (a)...

  18. 43 CFR 45.3 - How are time periods computed?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false How are time periods computed? 45.3 Section 45.3 Public Lands: Interior Office of the Secretary of the Interior CONDITIONS AND PRESCRIPTIONS IN FERC HYDROPOWER LICENSES General Provisions § 45.3 How are time periods computed? (a)...

  19. 19 CFR 158.21a - Time period.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 2 2011-04-01 2011-04-01 false Time period. 158.21a Section 158.21a Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY... While in Customs Custody § 158.21a Time period. An abatement or refund of duties shall be made in...

  20. 19 CFR 158.21a - Time period.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 2 2012-04-01 2012-04-01 false Time period. 158.21a Section 158.21a Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY... While in Customs Custody § 158.21a Time period. An abatement or refund of duties shall be made in...

  1. 19 CFR 158.21a - Time period.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 2 2010-04-01 2010-04-01 false Time period. 158.21a Section 158.21a Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY... While in Customs Custody § 158.21a Time period. An abatement or refund of duties shall be made in...

  2. Publication Trends in Acupuncture Research: A 20-Year Bibliometric Analysis Based on PubMed

    PubMed Central

    Dong, Ming; Zhou, Kehua; Mita, Carol; Liu, Jianping; Wayne, Peter M.

    2016-01-01

    Objective Acupuncture has become popular and widely practiced in many countries around the world. Despite the large amount of acupuncture-related literature that has been published, broader trends in the prevalence and scope of acupuncture research remain underexplored. The current study quantitatively analyzes trends in acupuncture research publications in the past 20 years. Methods A bibliometric approach was used to search PubMed for all acupuncture-related research articles including clinical and animal studies. Inclusion criteria were articles published between 1995 and 2014 with sufficient information for bibliometric analyses. Rates and patterns of acupuncture publication within the 20 year observational period were estimated, and compared with broader publication rates in biomedicine. Identified eligible publications were further analyzed with respect to study type/design, clinical condition addressed, country of origin, and journal impact factor. Results A total of 13,320 acupuncture-related publications were identified using our search strategy and eligibility criteria. Regression analyses indicated an exponential growth in publications over the past two decades, with a mean annual growth rate of 10.7%. This compares to a mean annual growth rate of 4.5% in biomedicine. A striking trend was an observed increase in the proportion of randomized clinical trials (RCTs), from 7.4% in 1995 to 20.3% in 2014, exceeding the 4.5% proportional growth of RCTs in biomedicine. Over the 20 year period, pain was consistently the most common focus of acupuncture research (37.9% of publications). Other top rankings with respect to medical focus were arthritis, neoplasms/cancer, pregnancy or labor, mood disorders, stroke, nausea/vomiting, sleep, and paralysis/palsy. Acupuncture research was conducted in 60 countries, with the top 3 contributors being China (47.4%), United States (17.5%), and United Kingdom (8.2%). Retrieved articles were published mostly in complementary and

  3. A Surrogate Test for Pseudo-periodic Time Series Data

    NASA Astrophysics Data System (ADS)

    Small, Michael; Harrison, Robert G.; Tse, C. K.

    2002-07-01

    Standard (linear) surrogate methods are only useful for time series exhibiting no pseudo-periodic structure. We describe a new algorithm that can distinguish between a noisy periodic orbit and deterministic non-periodic inter-cycle dynamics. Possible origins of deterministic non-periodic inter-cycle dynamics include: non-periodic linear or nonlinear dynamics, or chaos. This new algorithm is based on mimicking the large-scale dynamics with a local model, but obliterating the fine scale features with dynamic noise. We demonstrate the application of this method to artificial data and experimental time series, including human electrocardiogram (ECG) recordings during sinus rhythm and ventricular tachycardia (VT). The method is able to successfully differentiate between the chaotic Rössler system and a pseudo periodic realization of the Rössler equations with dynamic noise. Application to ECG data demonstrates that both sinus rhythm and VT exhibit nontrivial inter-cycle dynamics.

  4. A time-periodic reaction-diffusion epidemic model with infection period

    NASA Astrophysics Data System (ADS)

    Zhang, Liang; Wang, Zhi-Cheng

    2016-10-01

    In this paper, we propose a time-periodic and diffusive SIR epidemic model with constant infection period. By introducing the basic reproduction number R_0 via a next generation operator for this model, we show that the disease goes extinction if R_0 < 1; while the disease is uniformly persistent if R_0 > 1.

  5. An Analysis of 20 Years of Space Weathering Effects on the Boeing 376 Spacecraft

    NASA Technical Reports Server (NTRS)

    Frith, James; Anz-Meador, Phillip; Cowardin, Heather; Buckalew, Brent; Lederer, Susan

    2015-01-01

    The Boeing HS-376 spin stabilized spacecraft was a popular design that was launched continuously into geosynchronous orbit starting in 1980, with the last launch occurring in 2003. Over 50 of the HS-376 buses were produced to fulfill a variety of different communication missions for countries all over the world. The design of the bus is easily approximated as a telescoping cylinder that is covered with solar cells and an Earth-facing antenna that is despun at the top of the cylinder. The similarity in design and the number of spacecraft launched over a long period of time make the HS-376 a prime target for studying the effects of solar weathering on solar panels as a function of time. A selection of primarily non-operational HS-376 spacecraft launched over a 20-year time period were observed using the United Kingdom Infrared Telescope on Mauna Kea and multi-band, near-infrared photometry produced. Each spacecraft was observed for an entire night cycling through ZYJHK filters and time-varying colors produced to compare near-infrared color as a function of launch date. The resulting analysis shown here may help in the future to set launch date constraints on the parent object of unidentified debris objects or other unknown spacecraft.

  6. Altered speech following adenoidectomy: a 20 year experience.

    PubMed

    Stewart, K J; Ahmad, T; Razzell, R E; Watson, A C H

    2002-09-01

    Altered speech related to velopharyngeal insufficiency is a rare but well-recognised complication of adenoidectomy. Over a 20 year period, 42 patients were referred to the Edinburgh cleft team for investigation of altered speech persisting for more than 12 months after adenoidectomy. We studied the cases to ascertain the incidence, clinical features and causes of altered speech in these patients and to assess the efficacy of a selective treatment policy. All data were prospectively collected when the patients were assessed in a multidisciplinary clinic and investigated by videofluoroscopy. Nasopharyngoscopy was also possible in half of the patients. Overall, 27 patients were male and 15 were female, and their mean age was 6.5 years. The incidence was one in 1200 adenoidectomies. Diagnoses included five submucous cleft palates, six occult submucous cleft palates, 22 cases of velopharyngeal disproportion, seven developmental or neurological causes, one iatrogenic palatal injury and one case that defied diagnosis. In six patients treatment was not required, 13 responded to speech therapy and 23 required surgical intervention. The choice of operation was based on the findings at investigation. Ten patients were treated by a superiorly based pharyngeal flap, 10 underwent a sphincteric pharyngoplasty and three had an intravelar veloplasty. Speech outcome was assessed in 36 cases. Treatment resulted in significantly improved speech in all but one patient and normal speech in 16 patients. Persistently altered speech is a rare complication of adenoidectomy. Preoperative screening by clinical examination will prevent some but not all of such problems. When patients present they should undergo multidisciplinary assessment and multi-modality investigation. A good outcome can be anticipated in most patients.

  7. Spatial patterns of ENSO's interannual influences on lilacs vary with time and periodicity

    NASA Astrophysics Data System (ADS)

    Fu, Congsheng; Ji, Zhenming; Wei, Zhongwang

    2017-04-01

    The influences of solar activity and large-scale climate modes (e.g. the El Niño/Southern Oscillation - 'ENSO') have been identified in many geophysical processes. However, few studies have attempted to investigate the frequency characteristics and corresponding spatial patterns of the interannual influence of either solar activity or large-scale climate modes on phenology. In this study, the influences of solar activity (represented by sunspot number 'SSN') and ENSO on the first leaf and bloom dates of the common lilac and cloned lilac in the United States were analyzed for time series spanning ≥ 33 years using the wavelet coherence method. The spatial patterns in the influence of ENSO on the first leaf and bloom dates were investigated for different times and periodicities, using time series of ≥ 20 years. The combined influences of solar activity and ENSO on the first leaf and bloom dates of lilacs were identified for most of the stations with records spanning ≥ 33 years. In the 11-year band, both increasing solar activity (SSN) and El Niño caused delays in the first leaf and bloom events of the cloned lilac during the 1980s in the northeastern United States. The frequency characteristics and the spatial patterns of the influence of ENSO on the first leaf day and first bloom day were essentially consistent, and such spatial patterns vary with time and periodicity.

  8. Long-Term Instructional Development: A 20-Year ID and Implementation Project.

    ERIC Educational Resources Information Center

    Sullivan, Howard; Ice, Kay; Niedermeyer, Fred

    2000-01-01

    Discussion of long-term instructional development focuses on the development and implementation of a K-12 energy education curriculum over a 20-year period. Highlights include field testing; fund raising; learner performance on posttests; revisions and updates; and guidelines for long-term instructional development projects. (LRW)

  9. Participation in Intellectual Disability Research: A Review of 20 Years of Studies

    ERIC Educational Resources Information Center

    Cleaver, S.; Ouellette-Kuntz, H.; Sakar, A.

    2010-01-01

    Background: Researchers have noted difficulties in attracting adequate numbers of participants with intellectual disabilities (ID) to their studies. Methods: This study was a review of participation by adults with ID in research conducted in South Eastern Ontario over a 20-year period (1987-2006). Original research studies were identified by local…

  10. Pharmacogenetics research on chemotherapy resistance in colorectal cancer over the last 20 years.

    PubMed

    Panczyk, Mariusz

    2014-08-07

    During the past two decades the first sequencing of the human genome was performed showing its high degree of inter-individual differentiation, as a result of large international research projects (Human Genome Project, the 1000 Genomes Project International HapMap Project, and Programs for Genomic Applications NHLBI-PGA). This period was also a time of intensive development of molecular biology techniques and enormous knowledge growth in the biology of cancer. For clinical use in the treatment of patients with colorectal cancer (CRC), in addition to fluoropyrimidines, another two new cytostatic drugs were allowed: irinotecan and oxaliplatin. Intensive research into new treatment regimens and a new generation of drugs used in targeted therapy has also been conducted. The last 20 years was a time of numerous in vitro and in vivo studies on the molecular basis of drug resistance. One of the most important factors limiting the effectiveness of chemotherapy is the primary and secondary resistance of cancer cells. Understanding the genetic factors and mechanisms that contribute to the lack of or low sensitivity of tumour tissue to cytostatics is a key element in the currently developing trend of personalized medicine. Scientists hope to increase the percentage of positive treatment response in CRC patients due to practical applications of pharmacogenetics/pharmacogenomics. Over the past 20 years the clinical usability of different predictive markers has been tested among which only a few have been confirmed to have high application potential. This review is a synthetic presentation of drug resistance in the context of CRC patient chemotherapy. The multifactorial nature and volume of the issues involved do not allow the author to present a comprehensive study on this subject in one review.

  11. Pharmacogenetics research on chemotherapy resistance in colorectal cancer over the last 20 years

    PubMed Central

    Panczyk, Mariusz

    2014-01-01

    During the past two decades the first sequencing of the human genome was performed showing its high degree of inter-individual differentiation, as a result of large international research projects (Human Genome Project, the 1000 Genomes Project International HapMap Project, and Programs for Genomic Applications NHLBI-PGA). This period was also a time of intensive development of molecular biology techniques and enormous knowledge growth in the biology of cancer. For clinical use in the treatment of patients with colorectal cancer (CRC), in addition to fluoropyrimidines, another two new cytostatic drugs were allowed: irinotecan and oxaliplatin. Intensive research into new treatment regimens and a new generation of drugs used in targeted therapy has also been conducted. The last 20 years was a time of numerous in vitro and in vivo studies on the molecular basis of drug resistance. One of the most important factors limiting the effectiveness of chemotherapy is the primary and secondary resistance of cancer cells. Understanding the genetic factors and mechanisms that contribute to the lack of or low sensitivity of tumour tissue to cytostatics is a key element in the currently developing trend of personalized medicine. Scientists hope to increase the percentage of positive treatment response in CRC patients due to practical applications of pharmacogenetics/pharmacogenomics. Over the past 20 years the clinical usability of different predictive markers has been tested among which only a few have been confirmed to have high application potential. This review is a synthetic presentation of drug resistance in the context of CRC patient chemotherapy. The multifactorial nature and volume of the issues involved do not allow the author to present a comprehensive study on this subject in one review. PMID:25110414

  12. Permutation test for periodicity in short time series data

    PubMed Central

    Ptitsyn, Andrey A; Zvonic, Sanjin; Gimble, Jeffrey M

    2006-01-01

    Background Periodic processes, such as the circadian rhythm, are important factors modulating and coordinating transcription of genes governing key metabolic pathways. Theoretically, even small fluctuations in the orchestration of circadian gene expression patterns among different tissues may result in functional asynchrony at the organism level and may contribute to a wide range of pathologic disorders. Identification of circadian expression pattern in time series data is important, but equally challenging. Microarray technology allows estimation of relative expression of thousands of genes at each time point. However, this estimation often lacks precision and microarray experiments are prohibitively expensive, limiting the number of data points in a time series expression profile. The data produced in these experiments carries a high degree of stochastic variation, obscuring the periodic pattern and a limited number of replicates, typically covering not more than two complete periods of oscillation. Results To address this issue, we have developed a simple, but effective, computational technique for the identification of a periodic pattern in relatively short time series, typical for microarray studies of circadian expression. This test is based on a random permutation of time points in order to estimate non-randomness of a periodogram. The Permutated time, or Pt-test, is able to detect oscillations within a given period in expression profiles dominated by a high degree of stochastic fluctuations or oscillations of different irrelevant frequencies. We have conducted a comprehensive study of circadian expression on a large data set produced at PBRC, representing three different peripheral murine tissues. We have also re-analyzed a number of similar time series data sets produced and published independently by other research groups over the past few years. Conclusion The Permutated time test (Pt-test) is demonstrated to be effective for detection of periodicity in

  13. Particle energization through time-periodic helical magnetic fields.

    PubMed

    Mitra, Dhrubaditya; Brandenburg, Axel; Dasgupta, Brahmananda; Niklasson, Eyvind; Ram, Abhay

    2014-04-01

    We solve for the motion of charged particles in a helical time-periodic ABC (Arnold-Beltrami-Childress) magnetic field. The magnetic field lines of a stationary ABC field with coefficients A=B=C=1 are chaotic, and we show that the motion of a charged particle in such a field is also chaotic at late times with positive Lyapunov exponent. We further show that in time-periodic ABC fields, the kinetic energy of a charged particle can increase indefinitely with time. At late times the mean kinetic energy grows as a power law in time with an exponent that approaches unity. For an initial distribution of particles, whose kinetic energy is uniformly distributed within some interval, the probability density function of kinetic energy is, at late times, close to a Gaussian but with steeper tails.

  14. Return times at periodic points in random dynamics

    NASA Astrophysics Data System (ADS)

    Haydn, Nicolai; Todd, Mike

    2017-01-01

    We prove a quenched limiting law for random measures on subshifts at periodic points. We consider a family of measures {≤ft\\{{{μω}\\right\\}}ω \\in Ω } , where the ‘driving space’ Ω is equipped with a probability measure which is invariant under a transformation θ. We assume that the fibred measures {μω} satisfy a generalised invariance property and are ψ-mixing. We then show that for almost every ω the return times to cylinders A n at periodic points are in the limit compound Poisson distributed for a parameter ϑ which is given by the escape rate at the periodic point.

  15. Support-Staff Jobs Double in 20 Years, Outpacing Enrollment

    ERIC Educational Resources Information Center

    Brainard, Jeffrey; Fain, Paul; Masterson, Kathryn

    2009-01-01

    Colleges have added managers and support personnel at a steady, vigorous clip over the past 20 years, new research shows, far outpacing the growth in student enrollment and instructors. Support staff--like budget analysts, computer specialists, and loan counselors--nearly doubled from 1987 to 2007. Meanwhile, jobs for instructors increased by only…

  16. The Systems Librarian: Reflecting on 20 Years of Library Technology

    ERIC Educational Resources Information Center

    Breeding, Marshall

    2005-01-01

    In this column, the author relates his experiences in the use of library technology over his 20-year career at Vanderbilt University. He describes how computers in libraries have transformed almost every aspect of how the library provides its services and performs its work behind the scenes. In addition, the author shares a few successful…

  17. The Rainbow Reading Programme: A Review 20 Years on

    ERIC Educational Resources Information Center

    Dobson, Emma

    2013-01-01

    It has been 20 years since the Rainbow Reading programme was developed and trialled by its New Zealand creator, Meryl-Lynn Pluck. Rainbow Reading is an audio-facilitated reading programme, and is based on the method of assisted repeated reading. The programme is designed to provide older students reading below their chronological age with the…

  18. Are History Textbooks More "Considerate" after 20 Years?

    ERIC Educational Resources Information Center

    Berkeley, Sheri; King-Sears, Margaret E.; Hott, Brittany L.; Bradley-Black, Katherine

    2014-01-01

    Features of eighth-grade history textbooks were examined through replication of a 20-year-old study that investigated "considerateness" of textbooks. Considerate texts provide clear, coherent information and include features that promote students' comprehension, such as explicit use of organizational structures, a range of question types…

  19. 20 Years of Investing in a Clear, Healthy Lake Tahoe

    EPA Pesticide Factsheets

    Community Information Fact Sheet with information about Lake Tahoe's history, the roles of EPA, state, and local government in protecting the Lake Tahoe Basin, priorities for the next 20 years, as well as actions that you can take to protect Lake Tahoe.

  20. Teacher Education 1992 and 2012: Reflecting on 20 Years

    ERIC Educational Resources Information Center

    McKeown, Rosalyn

    2012-01-01

    Over the past 20 years education for sustainable development (ESD) has become part of the discourse in teacher education and the teaching community has a better grasp of ESD's action-oriented and participatory pedagogies. The International Network of Teacher Education Institutions (TEIs) associated with the UNESCO Chair on Reorienting Teacher…

  1. Residential Transitions among Adults with Intellectual Disability across 20 Years

    ERIC Educational Resources Information Center

    Woodman, Ashley C.; Mailick, Marsha R.; Anderson, Kristy A.; Esbensen, Anna J.

    2014-01-01

    The present study addresses critical gaps in the literature by examining residential transitions among 303 adults with intellectual disability (ID) over 10 years (Part 1) and 75 adults with Down syndrome over 20 years (Part 2). All adults lived at home at the start of the study, but many moved to a variety of settings. Several characteristics of…

  2. Reflections on 20 Years of Research on Violence and Trauma

    ERIC Educational Resources Information Center

    Forde, David R.

    2005-01-01

    This article is part of a special issue reflecting on what people have learned about violence and trauma over the past 20 years and where we need to go in the next 10 years. The author emphasizes the importance of learning to communicate in order to form effective community partnerships. Evidence-based research is noted as a methodological…

  3. Prediction of the 20-year incidence of diabetes in older Chinese

    PubMed Central

    Liu, Xiangtong; Fine, Jason Peter; Chen, Zhenghong; Liu, Long; Li, Xia; Wang, Anxin; Guo, Jin; Tao, Lixin; Mahara, Gehendra; Tang, Zhe; Guo, Xiuhua

    2016-01-01

    Abstract The competing risk method has become more acceptable for time-to-event data analysis because of its advantage over the standard Cox model in accounting for competing events in the risk set. This study aimed to construct a prediction model for diabetes using a subdistribution hazards model. We prospectively followed 1857 community residents who were aged ≥ 55 years, free of diabetes at baseline examination from August 1992 to December 2012. Diabetes was defined as a self-reported history of diabetes diagnosis, taking antidiabetic medicine, or having fasting plasma glucose (FPG) ≥ 7.0 mmol/L. A questionnaire was used to measure diabetes risk factors, including dietary habits, lifestyle, psychological factors, cognitive function, and physical condition. Gray test and a subdistribution hazards model were used to construct a prediction algorithm for 20-year risk of diabetes. Receiver operating characteristic (ROC) curves, bootstrap cross-validated Wolber concordance index (C-index) statistics, and calibration plots were used to assess model performance. During the 20-year follow-up period, 144 cases were documented for diabetes incidence with a median follow-up of 10.9 years (interquartile range: 8.0–15.3 years). The cumulative incidence function of 20-year diabetes incidence was 11.60% after adjusting for the competing risk of nondiabetes death. Gray test showed that body mass index, FPG, self-rated heath status, and physical activity were associated with the cumulative incidence function of diabetes after adjusting for age. Finally, 5 standard risk factors (poor self-rated health status [subdistribution hazard ratio (SHR) = 1.73, P = 0.005], less physical activity [SHR = 1.39, P = 0.047], 55–65 years old [SHR = 4.37, P < 0.001], overweight [SHR = 2.15, P < 0.001] or obesity [SHR = 1.96, P = 0.003], and impaired fasting glucose [IFG] [SHR = 1.99, P < 0.001]) were significantly associated with incident

  4. Classical and revival time periods of confined harmonic oscillator

    NASA Astrophysics Data System (ADS)

    Ghosh, P.; Ghosh, S.; Bera, N.

    2015-02-01

    We have used perturbation theory to compute energy eigenvalues, classical and the revival time periods for a one-dimensional harmonic oscillator confined in a box. First we have considered a simple harmonic oscillator as the unperturbed problem and boundary as perturbation. In next case, free particle in a box is considered as unperturbed problem that has been perturbed by a parabolic potential. We have used Fourier Grid Hamiltonian method to estimate classical and revival time period for the confined harmonic oscillator, which crosses smoothly from free particle in a box to a simple harmonic oscillator.

  5. [1986-2006: 20 years of failed international policy to control AIDS in Africa].

    PubMed

    Kerouedan, D

    2007-10-01

    Agencies of the United Nations and other international organizations involved in fighting AIDS in Africa have been wrong for 20 years. Despite this failure that was publicly avowed for the first time by a high UNAIDS official in Brazzaville in March 2006, the international community continues to propose a strategy based exclusively on organizational and financial solutions for a highly complex human tragedy that requires a much more comprehensive, coordinated public health approach. Organization of the fight against AIDS has taken many forms over the period between 1986 and 2006. The WHO Global Programme against AIDS program initiated only five years after the beginning of the epidemic in the United States was followed ten years later by the joint United Nations program named UNAIDS. The period between 2000 and 2006 saw a growing number of worldwide initiatives outside the framework of the United Nations. With programs based on cooperation of bilateral agencies, the European Commission, and the World Bank with expert technical agencies and civilian representatives, the whole international community felt that they were "in the driver's seat ". However analysis of the strategy deployed against AIDS during this period shows a shift from "total emphasis on prevention" (1986-1996) to "total emphasis on ARV treatment" (1996-2006). This shift occurred with no assessment of the benefits of the previous strategy for the main users, i.e., the populations of Africa and health care officials. Financial pledges have considerably increased in the context of global public partnerships such as the Global Fund against HIV/AIDS, TB and Malaria, with no change in the overall strategic vision to control the pandemic. There has been a total lack of planning and leadership in controlling the pandemic. Even though we failed to treat 3 million people before the end of 2005 within the framework of the "3x5" initiative despite the availability of ARV in Africa since 1998, WHO called for

  6. [Occupational medicine in Desio: 20 years of activities].

    PubMed

    Toffoletto, F

    1998-01-01

    We describe the main factors determining the evolution of the Occupational Medicine Department of Desio Hospital (UOOML) during last twenty years. We report the more meaningful experiences achieved during this period of time. We also describe the present organization of the department in relation to the main activities.

  7. The New 20-Year Global Precipitation Climatology Project (GPCP) Merged Satellite and Rainguage Monthly Analysis

    NASA Technical Reports Server (NTRS)

    Adler, Robert; Huffman, George; Xie, Ping Ping; Rudolf, Bruno; Gruber, Arnold; Janowiak, John

    1999-01-01

    A new 20-year, monthly, globally complete precipitation analysis has been completed as part of the World Climate Research Program's (WCRP/GEWEX) Global Precipitation Climatology Project (GPCP). This Version 2 of the community generated data set is a result of combining the procedures and data sets as described. The global, monthly, 2.5x 2.5 degree latitude-longitude product utilizes precipitation estimates from low-orbit microwave sensors (SSM/1) and geosynchronous IR sensors and raingauge information over land. The low-orbit microwave estimates are used to adjust or correct the geosynchronous IR estimates, thereby maximizing the utility of the more physically-based microwave estimates and the finer time sampling of the geosynchronous observations. Information from raingauges is blended into the analyses over land. In the 1986-present period TOVS-based precipitation estimates are adjusted to GPCP fields and used in polar regions to produce globally-complete results. The extension back to 1979 utilizes the procedures of Xie and Arkin and their OLR Precipitation Index (OPI). The 20-year climatology of the Version 2 GPCP analysis indicates the expected features of a very strong Pacific Ocean ITCZ and SPCZ with maximum 20-year means approaching 10 mm/day. A similar strength maximum over land is evident over Borneo. Weaker maxima in the tropics occur in the Atlantic ITCZ and over South America and Africa. In mid-latitudes of the Northern Hemisphere the Western Pacific and Western Atlantic maxima have values of approximately 7 mm/day, while in the Southern Hemisphere the mid-latitude maxima are located southeast of Africa, in mid-Pacific as an extension of the SPCZ and southeast of South America. In terms of global totals the GPCP analysis shows 2.7 mm/day (3.0 mm/day over ocean; 2.1 mm/day over land), similar to the Jaeger climatology, but not other climatologies. Zonal averages peak at 6 mm/day at 7*N with mid-latitude peaks of about 3 mm/day at 40-45* latitude

  8. Coherent structures in 3D viscous time-periodic flow

    NASA Astrophysics Data System (ADS)

    Znaien, J. G.; Speetjens, M. F. M.; Trieling, R. R.; Clercx, H. J. H.

    2010-11-01

    Periodically driven laminar flows occur in many industrial processes from food-mixing devices to micro-mixer in lab-on-a-chip systems. The present study is motivated by better understanding fundamental transport phenomena in three-dimensional viscous time-periodic flows. Both numerical simulation and three-dimensional Particle Tracking Velocimetry measurements are performed to investigate the 3D advection of a passive scalar in a lid-driven cylindrical cavity flow. The flow is forced by a time-periodic in-plane motion of one endwall via a given forcing protocol. We concentrate on the formation and interaction of coherent structures due to fluid inertia, which play an important role in 3D mixing by geometrically determining the tracer transport. The disintegration of these structures by fluid inertia reflects an essentially 3D route to chaos. Data from tracking experiments of small particles will be compared with predictions from numerical simulations on transport of passive tracers.

  9. Publication trends in the medical informatics literature: 20 years of "Medical Informatics" in MeSH

    PubMed Central

    2009-01-01

    Background The purpose of this study is to identify publication output, and research areas, as well as descriptively and quantitatively characterize the field of medical informatics through publication trend analysis over a twenty year period (1987–2006). Methods A bibliometric analysis of medical informatics citations indexed in Medline was performed using publication trends, journal frequency, impact factors, MeSH term frequencies and characteristics of citations. Results There were 77,023 medical informatics articles published during this 20 year period in 4,644 unique journals. The average annual article publication growth rate was 12%. The 50 identified medical informatics MeSH terms are rarely assigned together to the same document and are almost exclusively paired with a non-medical informatics MeSH term, suggesting a strong interdisciplinary trend. Trends in citations, journals, and MeSH categories of medical informatics output for the 20-year period are summarized. Average impact factor scores and weighted average impact factor scores increased over the 20-year period with two notable growth periods. Conclusion There is a steadily growing presence and increasing visibility of medical informatics literature over the years. Patterns in research output that seem to characterize the historic trends and current components of the field of medical informatics suggest it may be a maturing discipline, and highlight specific journals in which the medical informatics literature appears most frequently, including general medical journals as well as informatics-specific journals. PMID:19159472

  10. Analysis of time-domain scattering by periodic structures

    NASA Astrophysics Data System (ADS)

    Gao, Yixian; Li, Peijun

    2016-11-01

    This paper is devoted to the mathematical analysis of a time-domain electromagnetic scattering by periodic structures which are known as diffraction gratings. The scattering problem is reduced equivalently into an initial-boundary value problem in a bounded domain by using an exact transparent boundary condition. The well-posedness and stability of the solution are established for the reduced problem. Moreover, a priori energy estimates are obtained with minimum regularity requirement for the data and explicit dependence on the time.

  11. 50 CFR 221.3 - How are time periods computed?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 10 2013-10-01 2013-10-01 false How are time periods computed? 221.3 Section 221.3 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS PRESCRIPTIONS IN FERC HYDROPOWER LICENSES...

  12. 50 CFR 221.3 - How are time periods computed?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 10 2014-10-01 2014-10-01 false How are time periods computed? 221.3 Section 221.3 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS PRESCRIPTIONS IN FERC HYDROPOWER LICENSES...

  13. Physical Activity in High School during "Free-Time" Periods

    ERIC Educational Resources Information Center

    Silva, Pedro; Sousa, Michael; Sá, Carla; Ribeiro, José; Mota, Jorge

    2015-01-01

    The purpose of this study was to examine youth physical activity (PA) in free-time periods during high school days and their contribution to total PA. Differences in terms of sex, age, body mass index and school level were assessed in a sample of Portuguese adolescents. Participants totalled 213 (135 girls), aged 14.6 ± 1.7, from two different…

  14. 50 CFR 221.3 - How are time periods computed?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 10 2012-10-01 2012-10-01 false How are time periods computed? 221.3 Section 221.3 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS PRESCRIPTIONS IN FERC HYDROPOWER LICENSES...

  15. 50 CFR 221.3 - How are time periods computed?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false How are time periods computed? 221.3 Section 221.3 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS PRESCRIPTIONS IN FERC HYDROPOWER LICENSES...

  16. Time-periodic solutions of the Benjamin-Ono equation

    SciTech Connect

    Ambrose , D.M.; Wilkening, Jon

    2008-04-01

    We present a spectrally accurate numerical method for finding non-trivial time-periodic solutions of non-linear partial differential equations. The method is based on minimizing a functional (of the initial condition and the period) that is positive unless the solution is periodic, in which case it is zero. We solve an adjoint PDE to compute the gradient of this functional with respect to the initial condition. We include additional terms in the functional to specify the free parameters, which, in the case of the Benjamin-Ono equation, are the mean, a spatial phase, a temporal phase and the real part of one of the Fourier modes at t = 0. We use our method to study global paths of non-trivial time-periodic solutions connecting stationary and traveling waves of the Benjamin-Ono equation. As a starting guess for each path, we compute periodic solutions of the linearized problem by solving an infinite dimensional eigenvalue problem in closed form. We then use our numerical method to continue these solutions beyond the realm of linear theory until another traveling wave is reached (or until the solution blows up). By experimentation with data fitting, we identify the analytical form of the solutions on the path connecting the one-hump stationary solution to the two-hump traveling wave. We then derive exact formulas for these solutions by explicitly solving the system of ODE's governing the evolution of solitons using the ansatz suggested by the numerical simulations.

  17. Evolution Of USDOE Performance Assessments Over 20 Years

    SciTech Connect

    Seitz, Roger R.; Suttora, Linda C.

    2013-02-26

    Performance assessments (PAs) have been used for many years for the analysis of post-closure hazards associated with a radioactive waste disposal facility and to provide a reasonable expectation of the ability of the site and facility design to meet objectives for the protection of members of the public and the environment. The use of PA to support decision-making for LLW disposal facilities has been mandated in United States Department of Energy (USDOE) directives governing radioactive waste management since 1988 (currently DOE Order 435.1, Radioactive Waste Management). Prior to that time, PAs were also used in a less formal role. Over the past 20+ years, the USDOE approach to conduct, review and apply PAs has evolved into an efficient, rigorous and mature process that includes specific requirements for continuous improvement and independent reviews. The PA process has evolved through refinement of a graded and iterative approach designed to help focus efforts on those aspects of the problem expected to have the greatest influence on the decision being made. Many of the evolutionary changes to the PA process are linked to the refinement of the PA maintenance concept that has proven to be an important element of USDOE PA requirements in the context of supporting decision-making for safe disposal of LLW. The PA maintenance concept represents the evolution of the graded and iterative philosophy and has helped to drive the evolution of PAs from a deterministic compliance calculation into a systematic approach that helps to focus on critical aspects of the disposal system in a manner designed to provide a more informed basis for decision-making throughout the life of a disposal facility (e.g., monitoring, research and testing, waste acceptance criteria, design improvements, data collection, model refinements). A significant evolution in PA modeling has been associated with improved use of uncertainty and sensitivity analysis techniques to support efficient

  18. Evolution of US DOE Performance Assessments Over 20 Years - 13597

    SciTech Connect

    Suttora, Linda C.; Seitz, Roger R.

    2013-07-01

    Performance assessments (PAs) have been used for many years for the analysis of post-closure hazards associated with a radioactive waste disposal facility and to provide a reasonable expectation of the ability of the site and facility design to meet objectives for the protection of members of the public and the environment. The use of PA to support decision-making for LLW disposal facilities has been mandated in United States Department of Energy (US DOE) directives governing radioactive waste management since 1988 (currently DOE Order 435.1, Radioactive Waste Management). Prior to that time, PAs were also used in a less formal role. Over the past 20+ years, the US DOE approach to conduct, review and apply PAs has evolved into an efficient, rigorous and mature process that includes specific requirements for continuous improvement and independent reviews. The PA process has evolved through refinement of a graded and iterative approach designed to help focus efforts on those aspects of the problem expected to have the greatest influence on the decision being made. Many of the evolutionary changes to the PA process are linked to the refinement of the PA maintenance concept that has proven to be an important element of US DOE PA requirements in the context of supporting decision-making for safe disposal of LLW. The PA maintenance concept is central to the evolution of the graded and iterative philosophy and has helped to drive the evolution of PAs from a deterministic compliance calculation into a systematic approach that helps to focus on critical aspects of the disposal system in a manner designed to provide a more informed basis for decision-making throughout the life of a disposal facility (e.g., monitoring, research and testing, waste acceptance criteria, design improvements, data collection, model refinements). A significant evolution in PA modeling has been associated with improved use of uncertainty and sensitivity analysis techniques to support efficient

  19. [False aneurysm on dacron prosthesis, 20 years after aortofemoral bypass].

    PubMed

    Illuminati, G; Bertagni, A; Nasti, A G; Montesano, G

    2001-10-01

    A 85-year-old male developed a false, non septic, non anastomotic aneurysm, 20 years after right aorto-femoral Dacron grafting for claudication. On account of the proximity to the femoral anastomosis, and the association with a profunda femoris stenosis, a conventional surgical repair was preferred to an endovascular treatment. The patient underwent a successful aneurysm resection followed by PTFE interposition between the primary graft and the profunda femoris artery, with uneventful recovery.

  20. Neoplasia in immunosuppressed renal transplant patients: a 20-year experience

    SciTech Connect

    Krueger, T.C.; Tallent, M.B. Jr.; Richie, R.E.; Johnson, H.K.; MacDonell, R.C.; Turner, B.

    1985-05-01

    This review examines a 20-year experience in renal transplantation at our center to determine the effects of immunosuppression on the subsequent development of malignancies. Twenty patients had 21 malignancies from primary sites other than skin, yielding an incidence of 2.5%. There were 0.65 malignancies for each 100 cumulative patient years of immunosuppression. Suppression of the host immune response is associated with an increased incidence of malignancies.

  1. LaRC 20-Year Center Revitalization Plan

    NASA Technical Reports Server (NTRS)

    Mangum, Cathy H.; Harris, Charles E.; Allen, Cheryl L.; Craft, Stephen J.; Hope, Drew J.; Kegelman, Jerome T.; Mastaler, Michael D; Weiser, Erik S.

    2012-01-01

    LaRC has developed a 20-Year Center Revitalization Plan. The objective of this plan is to assure that the center infrastructure is sustainable for the long-term and that the center will have the essential facilities and laboratories to execute the future NASA mission. The plan was developed by a centerwide team, VITAL, and was approved by the Center Leadership Council (CLC) in March 2012. The revitalization plan will be implemented through the Center Master Planning process.

  2. A method for obtaining time-periodic Lp estimates

    NASA Astrophysics Data System (ADS)

    Kyed, Mads; Sauer, Jonas

    2017-01-01

    We introduce a method for showing a prioriLp estimates for time-periodic, linear, partial differential equations set in a variety of domains such as the whole space, the half space and bounded domains. The method is generic and can be applied to a wide range of problems. We demonstrate it on the heat equation. The main idea is to replace the time axis with a torus in order to reformulate the problem on a locally compact abelian group and to employ Fourier analysis on this group. As a by-product, maximal Lp regularity for the corresponding initial-value problem follows without the notion of R-boundedness. Moreover, we introduce the concept of a time-periodic fundamental solution.

  3. Posttraumatic Intrusion, Avoidance, and Social Functioning: A 20-Year Longitudinal Study

    ERIC Educational Resources Information Center

    Solomon, Zahava; Mikulincer, Mario

    2007-01-01

    The study assesses posttraumatic intrusion, avoidance, and social functioning among 214 Israeli combat veterans from the first Lebanon War with and without combat stress reaction (CSR) 1, 2, 3, and 20 years after the war. CSR veterans reported higher intrusion and avoidance than did non-CSR veterans. With time, there was a decline in these…

  4. The impact of lean production on musculoskeletal and psychosocial risks: an examination of sociotechnical trends over 20 years.

    PubMed

    Koukoulaki, Theoni

    2014-03-01

    This paper provides an extensive review of studies carried out in lean production environments in the last 20 years. It aims to identify the effects of lean production (negative or positive) on occupational health and related risk factors. Thirty-six studies of lean effects were accepted from the literature search and sorted by sector and type of outcome. Lean production was found to have a negative effect on health and risk factors; the most negative outcomes being found in the earliest studies in the automotive industry. However, examples of mixed and positive effects were also found in the literature. The strongest correlations of lean production with stress were found for characteristics found in Just-In-Time production that related to reduced cycle time and reduction of resources. Increased musculoskeletal risk symptoms were related to increases of work pace and lack of recovery time also found in Just-In-Time systems. An interaction model is developed to propose a pathway from lean production characteristics to musculoskeletal and psychosocial risk factors and also positive outcomes. An examination is also made of the changing focus of studies investigating the consequences of lean production over a 20-year period. Theories about the effects of lean production have evolved from a conceptualization that it is an inherently harmful management system, to a view that it can have mixed effects depending on the management style of the organization and the specific way it is implemented.

  5. The time-transgressive termination of the African Humid Period

    NASA Astrophysics Data System (ADS)

    Shanahan, Timothy M.; McKay, Nicholas P.; Hughen, Konrad A.; Overpeck, Jonathan T.; Otto-Bliesner, Bette; Heil, Clifford W.; King, John; Scholz, Christopher A.; Peck, John

    2015-02-01

    During the African Humid Period about 14,800 to 5,500 years ago, changes in incoming solar radiation during Northern Hemisphere summers led to the large-scale expansion and subsequent collapse of the African monsoon. Hydrologic reconstructions from arid North Africa show an abrupt onset and termination of the African Humid Period. These abrupt transitions have been invoked in arguments that the African monsoon responds rapidly to gradual forcing as a result of nonlinear land surface feedbacks. Here we present a reconstruction of precipitation in humid tropical West Africa for the past 20,000 years using the hydrogen isotope composition of leaf waxes preserved in sediments from Lake Bosumtwi, Ghana. We show that over much of tropical and subtropical Africa the monsoon responded synchronously and predictably to glacial reorganizations of overturning circulation in the Atlantic Ocean, but the response to the relatively weaker radiative forcing during the African Humid Period was more spatially and temporally complex. A synthesis of hydrologic reconstructions from across Africa shows that the termination of the African Humid Period was locally abrupt, but occurred progressively later at lower latitudes. We propose that this time-transgressive termination of the African Humid Period reflects declining rainfall intensity induced directly by decreasing summer insolation as well as the gradual southward migration of the tropical rainbelt that occurred during this interval.

  6. Periodic, Quasi-periodic and Chaotic Dynamics in Simple Gene Elements with Time Delays

    PubMed Central

    Suzuki, Yoko; Lu, Mingyang; Ben-Jacob, Eshel; Onuchic, José N.

    2016-01-01

    Regulatory gene circuit motifs play crucial roles in performing and maintaining vital cellular functions. Frequently, theoretical studies of gene circuits focus on steady-state behaviors and do not include time delays. In this study, the inclusion of time delays is shown to entirely change the time-dependent dynamics for even the simplest possible circuits with one and two gene elements with self and cross regulations. These elements can give rise to rich behaviors including periodic, quasi-periodic, weak chaotic, strong chaotic and intermittent dynamics. We introduce a special power-spectrum-based method to characterize and discriminate these dynamical modes quantitatively. Our simulation results suggest that, while a single negative feedback loop of either one- or two-gene element can only have periodic dynamics, the elements with two positive/negative feedback loops are the minimalist elements to have chaotic dynamics. These elements typically have one negative feedback loop that generates oscillations, and another unit that allows frequent switches among multiple steady states or between oscillatory and non-oscillatory dynamics. Possible dynamical features of several simple one- and two-gene elements are presented in details. Discussion is presented for possible roles of the chaotic behavior in the robustness of cellular functions and diseases, for example, in the context of cancer. PMID:26876008

  7. Time periodic perturbations and transport signatures in Floquet topological insulators

    NASA Astrophysics Data System (ADS)

    Farrell, Aaron; Pereg-Barnea, T.

    A Floquet topological insulator represents an out-of-equilibrium topological state. The topology of these systems emerges only when a time periodic perturbation is carefully applied. In time-periodic systems one can define quasi-energy states, which replace equilibrium stationary states (i.e. energy eigenstates). For appropriate time periodic potential strengths, a Floquet topological insulator exhibits edge localized quasi-energy states which lie in a gap of its quasi-energy spectrum. These edge states are a non-equilibrium analogue of the topologically protected edge-states in equilibrium topological insulators. In an equilibrium system such edge states lead to robust ``signature'' transport properties, e.g. a two-terminal conductivity of 2e2 / h . This talk will explore how these transport signatures translate to Floquet topological insulators. We will do this by developing and generalizing intuition borrowed from the field of photon-assited tunneling. We show that ultimately the signature transport properties of an equilibrium topological insulator do not directly hold in the out-of-equilibrium setting. This fact notwithstanding, we will provide an indirect way of retaining these transport signatures by using a so-called Floquet sum rule.

  8. Krylov-subspace acceleration of time periodic waveform relaxation

    SciTech Connect

    Lumsdaine, A.

    1994-12-31

    In this paper the author uses Krylov-subspace techniques to accelerate the convergence of waveform relaxation applied to solving systems of first order time periodic ordinary differential equations. He considers the problem in the frequency domain and presents frequency dependent waveform GMRES (FDWGMRES), a member of a new class of frequency dependent Krylov-subspace techniques. FDWGMRES exhibits many desirable properties, including finite termination independent of the number of timesteps and, for certain problems, a convergence rate which is bounded from above by the convergence rate of GMRES applied to the static matrix problem corresponding to the linear time-invariant ODE.

  9. 28. Graffiti in north cells: '20 years old 4315 CD ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. Graffiti in north cells: '20 years old 4315 C-D Mamoru Yoshimoto 5/24/45 180 days Kumamoto'; '18 ' ' years old 1406-A Haruo Yokoi 6/17/45 270 days Nagoya'; '31 ' ' years old 5604-B Masaki Nishii 5/24/45 180 days Kumamoto'; '19 ' ' years old 1806-B Masaharu Yoshida 5/24/45 180 days Hiroshima'; 135mm lens with electronic flash illumination. - Tule Lake Project Jail, Post Mile 44.85, State Route 139, Newell, Modoc County, CA

  10. Scheduling real-time, periodic jobs using imprecise results

    NASA Technical Reports Server (NTRS)

    Liu, Jane W. S.; Lin, Kwei-Jay; Natarajan, Swaminathan

    1987-01-01

    A process is called a monotone process if the accuracy of its intermediate results is non-decreasing as more time is spent to obtain the result. The result produced by a monotone process upon its normal termination is the desired result; the error in this result is zero. External events such as timeouts or crashes may cause the process to terminate prematurely. If the intermediate result produced by the process upon its premature termination is saved and made available, the application may still find the result unusable and, hence, acceptable; such a result is said to be an imprecise one. The error in an imprecise result is nonzero. The problem of scheduling periodic jobs to meet deadlines on a system that provides the necessary programming language primitives and run-time support for processes to return imprecise results is discussed. This problem differs from the traditional scheduling problems since the scheduler may choose to terminate a task before it is completed, causing it to produce an acceptable but imprecise result. Consequently, the amounts of processor time assigned to tasks in a valid schedule can be less than the amounts of time required to complete the tasks. A meaningful formulation of this problem taking into account the quality of the overall result is discussed. Three algorithms for scheduling jobs for which the effects of errors in results produced in different periods are not cumulative are described, and their relative merits are evaluated.

  11. Minimal model for short-time diffusion in periodic potentials.

    PubMed

    Emary, Clive; Gernert, Robert; Klapp, Sabine H L

    2012-12-01

    We investigate the dynamics of a single, overdamped colloidal particle, which is driven by a constant force through a one-dimensional periodic potential. We focus on systems with large barrier heights where the lowest-order cumulants of the density field, that is, average position and the mean-squared displacement, show nontrivial (nondiffusive) short-time behavior characterized by the appearance of plateaus. We demonstrate that this "cage-like" dynamics can be well described by a discretized master equation model involving two states (related to two positions) within each potential valley. Nontrivial predictions of our approach include analytic expressions for the plateau heights and an estimate of the "de-caging time" obtained from the study of deviations from Gaussian behavior. The simplicity of our approach means that it offers a minimal model to describe the short-time behavior of systems with hindered dynamics.

  12. Wet atmospheric deposition of nitrogen: 20 years measurement in Shenzhen City, China.

    PubMed

    Huang, Yilong; Lu, XiXi; Chen, Kai

    2013-01-01

    We presented measurements of wet deposition of NH(4)(+)-N and NO(3)(-)-N from 1986 to 2006 in Shenzhen City, China. Over the past 20 years, NO(3)(-)-N concentration had significantly increased, but a reverse trend was found for NH(4)(+)-N. The main form of total inorganic nitrogen (TIN) was NH(4)(+)-N and the average NH(4)(+)-N/NO(3)(-)-N ratio was 1.57 in this area. The contribution of NO(3)(-)-N to TIN increased from 28-42% in the period of 1986-2000 to 50-63% during 2001-2006. The increased deposition flux of NO(3)(-)-N resulted in the increasing trend of TIN, although NH(4)(+)-N showed a decreasing trend over time. Average deposition flux of TIN during 1986-2006 was 13.24 kg/ha/year, with a minimum value of 6.03kg/ha/year in 1988 and a maximum value of 20.52 kg/ha/year in 1997. Wet deposition fluxes of N appeared to vary with season, 81% occurred in the warm season (from April to September). The wet deposition of TIN to the Shenzhen Reservoir reached 8,902 kg in 2006, which contributed 9.95% of the total nonpoint pollution to the reservoir and will be increased in the future.

  13. Earth observation photography: Looking back 20 years after Skylab

    NASA Technical Reports Server (NTRS)

    Nicholson, James H.

    1992-01-01

    A committee of trained classroom teachers, backed by a volunteer team of technical experts and academic advisors has developed a program for earth science based on photographs obtained from low earth orbit. In selecting targeting objectives, immediate note was made of the fact nearly one generation (20 years) has passed since the United States' ambitious SKYLAB program was conducted. A critical part of those missions was the acquisition of earth photography using a six camera, multi-spectral camera system. This objective was systematically furthered through the term of three separate crew visits to the Space Station. Not merely an exercise in randomly photographing the Earth below, the purpose of the Earth Resource Experiment Package (EREP) was to determine what kind, and how much, photographic data could be acquired of the broad variety of Earth features witnessed on the mission's ground track. The collection of 35,000 photos produced by EREP represents the most complete coverage of Earth. However, it remains under used. GAS 324 intends to revisit, and to add a tier of relevancy to this inventory. The photography of GAS 324 should allow a direct examination and comparison of the changes in the globe in the last 20 years. format in both coverage and quality. The photogra phy acquired by CAN DO should allow a direct examination and comparison of the changes that have occured to the Globe in the last twenty years.

  14. Transient habitats limit development time for periodical cicadas.

    PubMed

    Karban, Richard

    2014-01-01

    Periodical cicadas (Magicicada spp.) mature in 13 or 17 years, the longest development times for any non-diapausing insects. Selection may favor prolonged development since nymphs experience little mortality and individuals taking 17 years have been shown to have greater fecundity than those taking 13 years. Why don't periodical cicadas take even longer to develop? Nymphs feed on root xylem fluid and move little. Ovipositing females prefer fast-growing trees at forest edges. I hypothesized that (1) adults emerging at edges would be heavier than those from forest interiors and (2) habitat changes could limit development time. I collected newly eclosed females that had neither fed as adults nor moved from their site of development. For M. septendecim, females from edges were 4.9% heavier than those from the interior. I assumed that emergence density indicated habitat quality and measured density at eight sites in 1979, 1996, and 2013. Over three generations, variation in densities was great; densities at two sites crashed, and at one site they exploded to 579/m2 Habitat transience may limit development time because only adults can reassess habitats and reposition offspring. In conclusion, cicadas are affected by habitat characteristics, habitats change over 17 years, and cicadas may emerge, mate, and redistribute their offspring to track habitat dynamics.

  15. Mimicking Nonequilibrium Steady States with Time-Periodic Driving

    NASA Astrophysics Data System (ADS)

    Raz, Oren; Subasi, Yigit; Jarzynski, Christopher

    Under static conditions, a system satisfying detailed balance generically relaxes to an equilibrium state in which there are no currents: to generate persistent currents, either detailed balance must be broken or the system must be driven in a time-dependent manner. A stationary system that violates detailed balance evolves to a nonequilibrium steady state (NESS) characterized by fixed currents. Conversely, a system that satisfies instantaneous detailed balance but is driven by the time-periodic variation of external parameters - also known as a stochastic pump (SP) - reaches a periodic state with non-vanishing currents. In both cases, these currents are maintained at the cost of entropy production. Are these two paradigmatic scenarios effectively equivalent? For discrete-state systems we establish a mapping between NESS and SP. Given a NESS characterized by a particular set of stationary probabilities, currents and entropy production rates, we show how to construct a SP with exactly the same (time-averaged) values. The mapping works in the opposite direction as well. These results establish a proof of principle: they show that SP are able to mimic the behavior of NESS, and vice-versa, within the theoretical framework of discrete-state stochastic thermodynamics.

  16. Mimicking Nonequilibrium Steady States with Time-Periodic Driving

    NASA Astrophysics Data System (ADS)

    Raz, O.; Subaşı, Y.; Jarzynski, C.

    2016-04-01

    Under static conditions, a system satisfying detailed balance generically relaxes to an equilibrium state in which there are no currents. To generate persistent currents, either detailed balance must be broken or the system must be driven in a time-dependent manner. A stationary system that violates detailed balance evolves to a nonequilibrium steady state (NESS) characterized by fixed currents. Conversely, a system that satisfies instantaneous detailed balance but is driven by the time-periodic variation of external parameters—also known as a stochastic pump (SP)—reaches a periodic state with nonvanishing currents. In both cases, these currents are maintained at the cost of entropy production. Are these two paradigmatic scenarios effectively equivalent? For discrete-state systems, we establish a mapping between nonequilibrium stationary states and stochastic pumps. Given a NESS characterized by a particular set of stationary probabilities, currents, and entropy production rates, we show how to construct a SP with exactly the same (time-averaged) values. The mapping works in the opposite direction as well. These results establish a proof of principle: They show that stochastic pumps are able to mimic the behavior of nonequilibrium steady states, and vice versa, within the theoretical framework of discrete-state stochastic thermodynamics. Nonequilibrium steady states and stochastic pumps are often used to model, respectively, biomolecular motors driven by chemical reactions and artificial molecular machines steered by the variation of external, macroscopic parameters. Our results loosely suggest that anything a biomolecular machine can do, an artificial molecular machine can do equally well. We illustrate this principle by showing that kinetic proofreading, a NESS mechanism that explains the low error rates in biochemical reactions, can be effectively mimicked by a constrained periodic driving.

  17. Postmating Female Control: 20 Years of Cryptic Female Choice.

    PubMed

    Firman, Renée C; Gasparini, Clelia; Manier, Mollie K; Pizzari, Tommaso

    2017-03-16

    Cryptic female choice (CFC) represents postmating intersexual selection arising from female-driven mechanisms at or after mating that bias sperm use and impact male paternity share. Although biologists began to study CFC relatively late, largely spurred by Eberhard's book published 20 years ago, the field has grown rapidly since then. Here, we review empirical progress to show that numerous female processes offer potential for CFC, from mating through to fertilization, although seldom has CFC been clearly demonstrated. We then evaluate functional implications, and argue that, under some conditions, CFC might have repercussions for female fitness, sexual conflict, and intersexual coevolution, with ramifications for related evolutionary phenomena, such as speciation. We conclude by identifying directions for future research in this rapidly growing field.

  18. Carcinoma of the hand: a 20-year experience

    SciTech Connect

    Bean, D.J.; Rees, R.S.; O'Leary, J.P.; Lynch, J.B.

    1984-08-01

    The authors reviewed their 20-year experience with cutaneous carcinoma of the hand and identified 70 cases (basal cell 23%, squamous cell 77%). The documented risk factors included solar radiation, trauma, and irradiation. Lesions were treated surgically with amputation, excision, skin graft, or flap closure, and nonsurgically with cryosurgery, curettage, 5-fluorouracil, or irradiation. The recurrence was lower with surgical treatment (3%) than with nonsurgical (33%). Regional lymphadenectomy was required in four patients for metastatic squamous cell carcinoma. Recurrence was greater (9%) and metastasis more common (38%) in patients with Marjolin's type of secondary squamous cell carcinoma than with solar-induced lesions. Cause is an important factor in outcome and should be considered in initial treatment and long-term management.

  19. Carcinoma of the hand: a 20-year experience

    SciTech Connect

    Bean, D.J.; Rees, R.S.; O'Leary, J.P.; Lynch, J.B.

    1984-08-01

    We reviewed our 20-year experience with cutaneous carcinoma of the hand and identified 70 cases (basal cell 23%, squamous cell 77%). The documented risk factors included solar radiation, trauma, and irradiation. Lesions were treated surgically with amputation, excision, skin graft, or flap closure, and nonsurgically with cryosurgery, curettage, 5-fluorouracil, or irradiation. The recurrence was lower with surgical treatment (3%) than with nonsurgical (33%). Regional lymphadenectomy was required in four patients for metastatic squamous cell carcinoma. Recurrence was greater (9%) and metastasis more common (38%) in patients with Marjolin's type of secondary squamous cell carcinoma than with solar-induced lesions. Cause is an important factor in outcome and should be considered in initial treatment and long-term management.

  20. Imaging the elastic properties of tissue: the 20 year perspective.

    PubMed

    Parker, K J; Doyley, M M; Rubens, D J

    2011-01-07

    After 20 years of innovation in techniques that specifically image the biomechanical properties of tissue, the evolution of elastographic imaging can be viewed from its infancy, through a proliferation of approaches to the problem to incorporation on research and then clinical imaging platforms. Ultimately this activity has culminated in clinical trials and improved care for patients. This remarkable progression represents a leading example of translational research that begins with fundamentals of science and engineering and progresses to needed improvements in diagnostic and monitoring capabilities applied to major categories of disease, surgery and interventional procedures. This review summarizes the fundamental principles, the timeline of developments in major categories of elastographic imaging, and concludes with recent results from clinical trials and forward-looking issues.

  1. Residential Transitions among Adults with Intellectual Disability across 20 Years

    PubMed Central

    Woodman, Ashley C.; Mailick, Marsha R.; Anderson, Kristy A.; Esbensen, Anna J.

    2014-01-01

    The present study addresses critical gaps in the literature by examining residential transitions among 303 adults with intellectual disability over 10 years (Part 1) and 75 adults with Down syndrome over 20 years (Part 2). All adults lived at home at the start of the study, but many moved to a variety of settings. Several characteristics of the adults with intellectual disability differed across settings, most notably adaptive behavior and the number of residential transitions, while characteristics such as age, type of disability, and behavior problems were less predictive of residential placements. The number of moves over the course of the study varied widely, with critical links to earlier family dynamics, social relationships, and health and adaptive behavior. PMID:25354121

  2. Global Patterns of Precipitation Anomalies Related to ENSO as Determined by the 20-Year GPCP Analysis

    NASA Technical Reports Server (NTRS)

    Adler, Robert; Curtis, Scott; Huffman, George; Bolvin, Dave; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The new 20-year, monthly, globally complete precipitation analysis of the Global Precipitation Climatology Project (GPCP) is used to analyze ENSO-related precipitation anomalies over the globe. This Version 2 of the community generated data set is global, monthly, at 2.5 deg x 2.5 deg latitude-longitude resolution and utilizes precipitation estimates from low-orbit microwave sensors (SSM/I) and geosynchronous IR sensors and raingauge information over land. In the 1987-present period the low-orbit microwave (SSM/I) estimates are used to adjust or correct the geosynchronous IR estimates, thereby maximizing the utility of the more physically-based microwave estimates and the finer time sampling of the geosynchronous observations. Information from raingauges is blended into the analyses over land. The extension back to 1979 utilizes the OLR Precipitation Index (OPI) for the satellite component. An ENSO Precipitation Index (ESPI) using gradients of precipitation anomalies in the Maritime-Continent/Pacific Ocean region is used to define El Nino/La Nina months during the 20-year record. Mean anomalies for El Nino and La Nina are examined along with variations with respect to season and for individual events. The El Nino and La Nina mean anomalies are near mirror images of each other and when combined produce an ENSO signal with significant spatial continuity over large distances. This El Nino minus La Nina standardized precipitation anomaly map shows the usual positive anomaly over the central and eastern Pacific Ocean with the negative anomaly over the maritime continent along with an additional negative anomaly over Brazil and the Atlantic Ocean extending into Africa and a positive anomaly over the Horn of Africa and the western Indian Ocean. From these features along the Equator narrow positive and negative anomalies extend into middle latitudes in a V-shaped pattern open to the East as described by previous investigators. A number of the features are shown to continue

  3. Langevin Dynamics with Space-Time Periodic Nonequilibrium Forcing

    NASA Astrophysics Data System (ADS)

    Joubaud, R.; Pavliotis, G. A.; Stoltz, G.

    2015-01-01

    We present results on the ballistic and diffusive behavior of the Langevin dynamics in a periodic potential that is driven away from equilibrium by a space-time periodic driving force, extending some of the results obtained by Collet and Martinez in (J Math Biol, 56(6):765-792 2008). In the hyperbolic scaling, a nontrivial average velocity can be observed even if the external forcing vanishes in average. More surprisingly, an average velocity in the direction opposite to the forcing may develop at the linear response level—a phenomenon called negative mobility. The diffusive limit of the non-equilibrium Langevin dynamics is also studied using the general methodology of central limit theorems for additive functionals of Markov processes. To apply this methodology, which is based on the study of appropriate Poisson equations, we extend recent results on pointwise estimates of the resolvent of the generator associated with the Langevin dynamics. Our theoretical results are illustrated by numerical simulations of a two-dimensional system.

  4. Desensitization to media violence over a short period of time.

    PubMed

    Fanti, Kostas A; Vanman, Eric; Henrich, Christopher C; Avraamides, Marios N

    2009-01-01

    This study investigated the desensitization to violence over a short period of time. Participants watched nine violent movie scenes and nine comedy scenes, and reported whether they enjoyed the violent or comedy scenes and whether they felt sympathetic toward the victim of violence. Using latent growth modeling, analyses were carried out to investigate how participants responded to the different scenes across time. The findings of this study suggested that repeated exposure to media violence reduces the psychological impact of media violence in the short term, therefore desensitizing viewers to media violence. As a result, viewers tended to feel less sympathetic toward the victims of violence and actually enjoy more the violence portrayed in the media. Additionally, desensitization to media violence was better represented by a curvilinear pattern, whereas desensitization to comedy scenes was better represented by a linear pattern. Finally, trait aggression was not related to the pattern of change over time, although significant effects were found for initial reports of enjoyment and sympathy.

  5. Relaxation Characteristics of 828 DGEBA Epoxy Over Long Time Periods

    NASA Astrophysics Data System (ADS)

    Hoo, Jasmine; Reprogle, Riley C.; Wisler, Brian; Arechederra, Gabriel K.; McCoy, John D.; Kropka, Jamie M.; Long, Kevin N.

    The mechanical relaxation response in uniaxial compression of a diglycidyl ether of bisphenol-A epoxy was studied over long time periods. The epoxy, 828DEA, was Epon 828 cured with diethanolamine (DEA). A sample was compressed at constant strain rate and held at various strain levels for days to allow the sample to relax. The sample was then compressed further and held once more. The relaxation curves were fit with a stretched exponential function. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  6. Simulation of estimating periodicity of seasonally stationary time series

    SciTech Connect

    Tian, C.J.

    1984-06-01

    Herein, some common periodicity estimation methods: the periodogram analysis, the maximum entropy spectral method, the successive average method as well as the graphic method are considered. For comparing these methods and verifying their practical efficiency, simulations are performed on several groups of seasonal stationary time series which are generated by the model x(t) = v(t) + z(t). v(t) being a seasonal component with different forms (Sinusoid, unequal amptitude oscillation, slope signal, exponential decay signal and block signal etc.) and z(t) being autoregressive process under different levels of signal-noise ratio. Computational results, comprehensively illustrate that the successive average method is easier to carry out and more efficient in practice.

  7. Swimming and transport of bacteria in time-periodic flows

    NASA Astrophysics Data System (ADS)

    Winter, Rebecca; Patteson, Alison; Gagnon, David; Arratia, Paulo

    The transport of bacteria can be highly influenced by external flows in oceans, rivers, and intestinal tracts. This has implications in biological systems for the performance of major biological processes, such as biofilm formation. In this study, we experimentally investigate the aggregation and transport of swimming Vibrio cholerae bacteria in time-periodic flows. Bacteria are placed in a well-characterized flow, and bacterial concentrations are recorded for a range of Reynolds numbers (Re) that spans two orders of magnitude, from 0.1 to 10. It is generally found that bacteria deplete from regions of high deformation rate and accumulate near vortices. This phenomenon seems to be dictated by a combination of bacterial activity and background flow vorticity. R.W. supported by NSF-GRFP.

  8. Navy Global Predictions for the Dynamo Time Period

    NASA Astrophysics Data System (ADS)

    Reynolds, C. A.; Ridout, J. A.; Flatau, M. K.; Chen, J.; Richman, J. G.; Jensen, T. G.; Shriver, J. F.

    2014-12-01

    The performance of 30-day simulations of the Navy Global Environmental Model (NAVGEM) is evaluated under several metrics. The time period of interest is the DYNAMO (Dynamics of Madden Julian Oscillation) field experiment period, starting late October 2011. The NAVGEM experiments are run at an effective 37-km resolution with several different SST configurations. The in the first set of experiments, the initial SST analysis, provided by the NCODA (Navy Coupled Ocean Data Assimilation) system, is either held fixed to the initial value (fixed SST) or updated every 6 hours. These forecasts are compared with forecasts in which the SST is updated with 3-h analyses from the Hybrid Coordinate Ocean Model (HYCOM), and forecasts in which NAVGEM is interactively coupled to HYCOM. Experiments are also performed with different physical parameterization options. The extended integrations are verified using observed OLR, TRMM precipitation estimates, and global analyses. The use of fixed SSTs is clearly sub-optimal. Biases in monthly mean fields are far more pronounced in the simulations where the SST is held fixed as compared to those in simulations where updated SST analyses are used. Biases in the monthly mean fields are further reduced when NAVGEM is coupled to HYCOM. Differences in SST can "migrate" to substantial changes in the time-mean land-surface temperatures, illustrating the substantial impact of SSTs over the full domain. Concerning the simulation of the MJO, some improvement is noted when the system is fully coupled, although the simulations still exhibit deficiencies such as eastward propagation that is too slow, and difficulty propagating over the maritime continent. Simulations that are started every 5 days indicate that the NAVGEM uncoupled system has difficulty predicting MJO initiation, but simulations started when the MJO is active in the Indian Ocean are able to capture eastward propagation characteristics. The coupled NAVGEM-HYCOM system shows ability to

  9. A 20-year simulated climatology of global dust aerosol deposition.

    PubMed

    Zheng, Yu; Zhao, Tianliang; Che, Huizheng; Liu, Yu; Han, Yongxiang; Liu, Chong; Xiong, Jie; Liu, Jianhui; Zhou, Yike

    2016-07-01

    Based on a 20-year (1991-2010) simulation of dust aerosol deposition with the global climate model CAM5.1 (Community Atmosphere Model, version 5.1), the spatial and temporal variations of dust aerosol deposition were analyzed using climate statistical methods. The results indicated that the annual amount of global dust aerosol deposition was approximately 1161±31Mt, with a decreasing trend, and its interannual variation range of 2.70% over 1991-2010. The 20-year average ratio of global dust dry to wet depositions was 1.12, with interannual variation of 2.24%, showing the quantity of dry deposition of dust aerosol was greater than dust wet deposition. High dry deposition was centered over continental deserts and surrounding regions, while wet deposition was a dominant deposition process over the North Atlantic, North Pacific and northern Indian Ocean. Furthermore, both dry and wet deposition presented a zonal distribution. To examine the regional changes of dust aerosol deposition on land and sea areas, we chose the North Atlantic, Eurasia, northern Indian Ocean, North Pacific and Australia to analyze the interannual and seasonal variations of dust deposition and dry-to-wet deposition ratio. The deposition amounts of each region showed interannual fluctuations with the largest variation range at around 26.96% in the northern Indian Ocean area, followed by the North Pacific (16.47%), Australia (9.76%), North Atlantic (9.43%) and Eurasia (6.03%). The northern Indian Ocean also had the greatest amplitude of interannual variation in dry-to-wet deposition ratio, at 22.41%, followed by the North Atlantic (9.69%), Australia (6.82%), North Pacific (6.31%) and Eurasia (4.36%). Dust aerosol presented a seasonal cycle, with typically strong deposition in spring and summer and weak deposition in autumn and winter. The dust deposition over the northern Indian Ocean exhibited the greatest seasonal change range at about 118.00%, while the North Atlantic showed the lowest seasonal

  10. The microbiologic profile of diabetic foot infections in Turkey: a 20-year systematic review: diabetic foot infections in Turkey.

    PubMed

    Hatipoglu, M; Mutluoglu, M; Uzun, G; Karabacak, E; Turhan, V; Lipsky, B A

    2014-06-01

    The causative pathogens in diabetic foot infections differ in studies of European compared with Asian populations. The purpose of this study was to determine the causative microorganisms and their antibiotic sensitivity patterns in diabetic patients with a foot infection in Turkey, a country at the crossroads of these two continents. We performed a comprehensive literature search to identify all published studies pertaining to DFIs in patients cared for in Turkey. To assess changes in causative organisms and their antibiotic sensitivity patterns over time, we compared the results of just the most recent 5 years (2007-2011) with those of the past 20-years (1989-2011). We identified 31 studies meeting our inclusion criteria. Overall, these studies reported 2,097 patients, from whom 1,974 microorganisms were isolated. The total percentage of gram-negative and gram-positive aerobic bacteria were similar in each of the assessed periods. The rate of isolation of Staphylococcus aureus during the entire period, compared with just the past 5 years, was 23.8% and 19.1%, respectively, while the rate of methicillin-resistant S. aureus was 7.8% and 5.7%, respectively. The isolation rate of Pseudomonas aeruginosa was 13.7% for the entire period and 14.9% for the past 5 years. While linezolid, vancomycin and teicoplanin were the most active agents against gram-positive microorganisms, imipenem and cefoperazone-sulbactam were the most active against gram-negative microorganisms. This systematic review demonstrated few substantial changes in diabetic foot microbiology over the past 20 years. The data may help develop and update local clinical guidelines regarding antibiotic therapy for diabetic foot infections in Turkey. Further studies, especially with optimal culture methods, would be useful to validate these findings.

  11. [Interdisciplinary orthodontic surgical treatment of children with cleft lip and palate from 9 to 20 years of age].

    PubMed

    Kuijpers-Jagtman, A M; Mink van der Molen, A B; Bierenbroodspot, F; Borstlap, W A

    2015-11-01

    Cleft lip and palate is a common congenital malformation with a prevalence of 1:600 newborns. Children with orofacial clefts are treated by an interdisciplinary team of specialists while parents and child play a key role in their own care process. The orthodontic and facial orthopedic treatment of a child with a cleft takes many years. Children often get bored of the long treatment and this can cause problems with compliance and oral hygiene. Therefore it is advisable to distinguish 5 well-defined stages in the orthodontic treatment and to attempt to have some 'orthodontics free' time in between. The 3 orthodontic treatment phases between the age of 9 and 20 years consist of orthodontic treatment concerning the closing of the cleft with a bone transplant, the treatment of the permanent dentition and, finally, a possible combined orthodontic surgical treatment at the end of the period of growth. Good interdisciplinary collaboration among the different dental disciplines is essential in this regard.

  12. 20 years of leptin: connecting leptin signaling to biological function.

    PubMed

    Allison, Margaret B; Myers, Martin G

    2014-10-01

    Hypothalamic leptin action promotes negative energy balance and modulates glucose homeostasis, as well as serving as a permissive signal to the neuroendocrine axes that control growth and reproduction. Since the initial discovery of leptin 20 years ago, we have learned a great deal about the molecular mechanisms of leptin action. An important aspect of this has been the dissection of the cellular mechanisms of leptin signaling, and how specific leptin signals influence physiology. Leptin acts via the long form of the leptin receptor LepRb. LepRb activation and subsequent tyrosine phosphorylation recruits and activates multiple signaling pathways, including STAT transcription factors, SHP2 and ERK signaling, the IRS-protein/PI3Kinase pathway, and SH2B1. Each of these pathways controls specific aspects of leptin action and physiology. Important inhibitory pathways mediated by suppressor of cytokine signaling proteins and protein tyrosine phosphatases also limit physiologic leptin action. This review summarizes the signaling pathways engaged by LepRb and their effects on energy balance, glucose homeostasis, and reproduction. Particular emphasis is given to the multiple mouse models that have been used to elucidate these functions in vivo.

  13. Adaptive stabilization of discrete-time systems using linear periodically time varying controllers

    NASA Technical Reports Server (NTRS)

    Ortega, Romeo; Albertos, Pedro; Lozano, Rogelio

    1988-01-01

    A direct adaptive scheme based on the use of linear time-varying periodic controllers is proposed which estimates online the periodic coefficients of the controller. It is shown that adaptive stabilization is attained for all possibly nonstably invertible plants of known order but unknown delay. Although no appeal is made to persistency of excitation arguments, a provision is needed to avoid the singularity of an estimated matrix, this property being required only for the analysis and not the control calculations.

  14. Genetics of hypertrophic cardiomyopathy after 20 years: clinical perspectives.

    PubMed

    Maron, Barry J; Maron, Martin S; Semsarian, Christopher

    2012-08-21

    Hypertrophic cardiomyopathy (HCM) is the most common familial heart disease with vast genetic heterogeneity, demonstrated over the past 20 years. Mutations in 11 or more genes encoding proteins of the cardiac sarcomere (>1,400 variants) are responsible for (or associated with) HCM. Explosive progress achieved in understanding the rapidly evolving science underlying HCM genomics has resulted in fee-for-service testing, making genetic information widely available. The power of HCM mutational analysis, albeit a more limited role than initially envisioned, lies most prominently in screening family members at risk for developing disease and excluding unaffected relatives, which is information not achievable otherwise. Genetic testing also allows expansion of the broad HCM disease spectrum and diagnosis of HCM phenocopies with different natural history and treatment options, but is not a reliable strategy for predicting prognosis. Interfacing a heterogeneous disease such as HCM with the vast genetic variability of the human genome, and high frequency of novel mutations, has created unforeseen difficulties in translating complex science (and language) into the clinical arena. Indeed, proband diagnostic testing is often expressed on a probabilistic scale, which is frequently incompatible with clinical decision making. Major challenges rest with making reliable distinctions between pathogenic mutations and benign variants, and those judged to be of uncertain significance. Genotyping in HCM can be a powerful tool for family screening and diagnosis. However, wider adoption and future success of genetic testing in the practicing cardiovascular community depends on a standardized approach to mutation interpretation, and bridging the communication gap between basic scientists and clinicians.

  15. 20 Years of persistent identifiers - Which systems are here to stay?

    NASA Astrophysics Data System (ADS)

    Klump, Jens; Huber, Robert; Lehnert, Kerstin

    2016-04-01

    Web-based persistent identifiers have been around for more than 20 years, a period long enough to start observing patterns of success and failure. Persistent identifiers were invented to address challenges arising from the distributed and disorganised nature of the internet, which not only allowed new technologies to emerge, it also made it difficult to maintain a persistent record of science. Persistent identifiers now allow unambiguous identification of resources on the net. The expectations were that persistent identifiers would lead to greater accessibility, transparency and reproducibility of research results. Over the past two decades a number of persistent identifier systems have been built, one of them being Digital Object Identifiers (DOI). While DOI were originally invented by the publishing industry, they quickly became an established way for the identification of research resources. At first, these resources referred to scholarly literature and related resources. Other identifier systems, some of them using DOI as an example, were developed as grass-roots efforts by the scientific community. The concept of using persistent identifiers has since been expanded to other, non-textual resources, like datasets (DOI, EPIC) and geological specimens (IGSN), and more recently to authors and contributors of scholarly works (ORCID), and to software and instruments. A common witticism states that "a great thing about standards is that there are so many to choose from." Setting up identifier systems is technically trivial. The real challenge lies in creating a governance system for the respective identifiers. Which systems will stand the test of time? Drawing on data from the Registry of Research Data Repositories (re3data.org) and our own experience in the field, this presentation looks at the history and adoption of existing identifier systems and how this gives us some indications towards factors influencing sustainability of these systems.

  16. Accelerated 20-year sunlight exposure simulation of a photochromic foldable intraocular lens in a rabbit model

    PubMed Central

    Werner, Liliana; Abdel-Aziz, Salwa; Peck, Carolee Cutler; Monson, Bryan; Espandar, Ladan; Zaugg, Brian; Stringham, Jack; Wilcox, Chris; Mamalis, Nick

    2011-01-01

    PURPOSE To assess the long-term biocompatibility and photochromic stability of a new photochromic hydrophobic acrylic intraocular lens (IOL) under extended ultraviolet (UV) light exposure. SETTING John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. DESIGN Experimental study. METHODS A Matrix Aurium photochromic IOL was implanted in right eyes and a Matrix Acrylic IOL without photochromic properties (n = 6) or a single-piece AcrySof Natural SN60AT (N = 5) IOL in left eyes of 11 New Zealand rabbits. The rabbits were exposed to a UV light source of 5 mW/cm2 for 3 hours during every 8-hour period, equivalent to 9 hours a day, and followed for up to 12 months. The photochromic changes were evaluated during slitlamp examination by shining a penlight UV source in the right eye. After the rabbits were humanely killed and the eyes enucleated, study and control IOLs were explanted and evaluated in vitro on UV exposure and studied histopathologically. RESULTS The photochromic IOL was as biocompatible as the control IOLs after 12 months under conditions simulating at least 20 years of UV exposure. In vitro evaluation confirmed the retained optical properties, with photochromic changes observed within 7 seconds of UV exposure. The rabbit eyes had clinical and histopathological changes expected in this model with a 12-month follow-up. CONCLUSIONS The new photochromic IOL turned yellow only on exposure to UV light. The photochromic changes were reversible, reproducible, and stable over time. The IOL was biocompatible with up to 12 months of accelerated UV exposure simulation. PMID:21241924

  17. Rationale, scope, and 20-year experience of vascular surgical training with lifelike pulsatile flow models.

    PubMed

    Eckstein, Hans-Henning; Schmidli, Jürg; Schumacher, Hardy; Gürke, Lorenz; Klemm, Klaus; Duschek, Nikolaus; Meile, Toni; Assadian, Afshin

    2013-05-01

    Vascular surgical training currently has to cope with various challenges, including restrictions on work hours, significant reduction of open surgical training cases in many countries, an increasing diversity of open and endovascular procedures, and distinct expectations by trainees. Even more important, patients and the public no longer accept a "learning by doing" training philosophy that leaves the learning curve on the patient's side. The Vascular International (VI) Foundation and School aims to overcome these obstacles by training conventional vascular and endovascular techniques before they are applied on patients. To achieve largely realistic training conditions, lifelike pulsatile models with exchangeable synthetic arterial inlays were created to practice carotid endarterectomy and patch plasty, open abdominal aortic aneurysm surgery, and peripheral bypass surgery, as well as for endovascular procedures, including endovascular aneurysm repair, thoracic endovascular aortic repair, peripheral balloon dilatation, and stenting. All models are equipped with a small pressure pump inside to create pulsatile flow conditions with variable peak pressures of ~90 mm Hg. The VI course schedule consists of a series of 2-hour modules teaching different open or endovascular procedures step-by-step in a standardized fashion. Trainees practice in pairs with continuous supervision and intensive advice provided by highly experienced vascular surgical trainers (trainer-to-trainee ratio is 1:4). Several evaluations of these courses show that tutor-assisted training on lifelike models in an educational-centered and motivated environment is associated with a significant increase of general and specific vascular surgical technical competence within a short period of time. Future studies should evaluate whether these benefits positively influence the future learning curve of vascular surgical trainees and clarify to what extent sophisticated models are useful to assess the level of

  18. A 20-year follow-up of signs and symptoms of temporomandibular disorders and malocclusions in subjects with and without orthodontic treatment in childhood.

    PubMed

    Egermark, Inger; Magnusson, Tomas; Carlsson, Gunnar E

    2003-04-01

    This investigation analyzes the influence of orthodontic treatment on signs and symptoms of temporomandibular disorders (TMDs) and different malocclusions during a 20-year period. Originally, 402 randomly selected 7-, 11-, and 15-year-old subjects were examined clinically and by means of a questionnaire for signs and symptoms of TMDs. The examination was repeated after five and ten years. After 20 years, 320 subjects (85% of the traced subjects) completed the questionnaire. The oldest age group,now 35 years of age, was invited to a clinical examination, and 100 subjects (81% of the traced subjects) were examined. The correlations between signs and symptoms of TMD and different malocclusions were mainly weak, although sometimes statistically significant. Lateral forced bite and unilateral crossbite were correlated with TMD signs and symptoms at the 10- and 20-year follow-ups (r = 0.38, P < .05 and r = 0.34, P < .01, respectively). Subjects with malocclusion over a long period of time tended to report more symptoms of TMD and to show a higher dysfunction index, compared with subjects with no malocclusion at all. There were no statistically significant differences in the prevalence of TMD signs and symptoms between subjects with or without previous experience of orthodontic treatment. This 20-year follow-up supports the opinion that no single occlusal factor is of major importance for the development of TMD, but a lateral forced bite between retruded contact position (RCP) and intercuspal position (ICP), as well as unilateral crossbite, may be a potential risk factor in this respect. Furthermore, subjects with a history of orthodontic treatment do not run a higher risk of developing TMD later in life, compared with subjects with no such experience.

  19. 20 years of SAR measurements along the NAFS: interseismic deformation

    NASA Astrophysics Data System (ADS)

    Stramondo, S.; Walter, T. R.; Ergintav, S.; Diao, F.; Wang, R.; Polcari, M.; Serpelloni, E.; Devoti, R.

    2014-12-01

    A comprehensive analysis of the earthquake cycle is a key issue for the definition of the hazard in seismic areas. Advanced SAR Interferometry (A-InSAR) techniques have today a key role in Earth Sciences thanks to the capability to detect and measure slow surface movements along wide areas, and to follow the evolution of signal along a certain time periods. A-InSAR techniques have been applied to large datasets of SAR images spanning long time intervals and, together with in-situ surveys and ground measurements, can provide suitable information about the causes of post seismic (deformation rebound or residual strain release) and interseismic (seismic, creep) movements. In the framework of FP7 MARSITE (Marmara Supersite) project we have investigated the Western sector of North Anatolian Fault System (NAFS) from Istanbul toward Duzce area. From West toward the Marmara Sea region (Mudurnu/Akyaz) the NAFS begins to lose its single fault line character and splays into a complex fault system. The main Marmara Fault is argued to be a very young structure and exhibits typical characteristics of a major strike slip fault. In 1999 the August 17th Izmit earthquake was followed few months later by the Duzce mainshock. We compare the A-InSAR results to permanent GPS stations installed in the region after the Izmit/Duzce earthquakes. These observations allow studying the post-seismic deformation of the 1999 Izmit/Düzce earthquake. We investigate the response of the eastern Marmara Fault to the quasi-static loading caused by Izmit/Düzce earthquakes. Overlapped post-seismic processes of fault creep (or afterslip) and viscoelastic relaxation of the lower crust and the upper mantle were investigated. We firstly estimated the viscoelastic relaxation effect using well covered long-term GPS data. This relaxation effect was subtracted from the InSAR data and the remaining InSAR data was inverted to identify localized slip variation along the MMF. Our inversion results imply that part

  20. Alternative Visions of Satellite Communication Economics in the 2010-2020 Time Period

    NASA Astrophysics Data System (ADS)

    Pelton, Joseph N.

    2002-01-01

    Satellite communications technologies have been gradually improving for over 35 years. Quality and reliability of equipment and services increased dramatically from the 1960s until the early 1980s. In the last 20 years improvements have been progressing steadily but in less dramatic fashion. This paper addresses three new satellite technologies that may be able to rekindle the very rapid prior growth pattern and achieve dramatic new systems economies in the 2010 to 2020 time period. The future could thus see the extension of conventional satellite technologies that produces a scenario in which satellite economics may become progressively less competitive with alternative telecommunications systems. On the other hand the authors explore three possible new technologies that produce alternative economic scenarios for the future. These are: 1) a tethered geo platform network, 2) advanced peizo-electric shaped antennas on a geo platform system, and 3) a geo platform that is constituted by a swarm of nanosatellites. Each of these systems requires significant new research and development. Which of these, if any, will form part of the successful satellite communications designs in the future is unclear at present. Each alternative, however, promises progressive economic cost reductions that could make future satellite networks highly competitive for a variety of broadband services and, potentially, even with some fiber optic transmissions. This paper outlines the technology needed for future competitiveness in such satellite systems, and creates an economic model that analyzes the potential viability and profitability of each system. Further analysis examines the overall business cases. These also test the sensitivity of these systems to more reliable and less costly new launch systems that, if available, would both accelerate the deployment of new satellite communications technologies as well as decrease the cost of all satellite systems.

  1. NIR Color vs Launch Date: A 20-Year Analysis of Space Weathering Effects on the Boeing 376 Spacecraft

    NASA Technical Reports Server (NTRS)

    Frith, James; Anz-Meador, Philip; Lederer, Sue; Cowardin, Heather; Buckalew, Brent

    2015-01-01

    The Boeing HS-376 spin stabilized spacecraft was a popular design that was launched continuously into geosynchronous orbit starting in 1980 with the last launch occurring in 2002. Over 50 of the HS-376 buses were produced to fulfill a variety of different communication missions for countries all over the world. The design of the bus is easily approximated as a telescoping cylinder that is covered with solar cells and an Earth facing antenna that is despun at the top of the cylinder. The similarity in design and the number of spacecraft launched over a long period of time make the HS-376 a prime target for studying the effects of solar weathering on solar panels as a function of time. A selection of primarily non-operational HS-376 spacecraft launched over a 20 year time period were observed using the United Kingdom Infrared Telescope on Mauna Kea and multi-band near-infrared photometry produced. Each spacecraft was observed for an entire night cycling through ZYJHK filters and time-varying colors produced to compare near-infrared color as a function of launch date. The resulting analysis shown here may help in the future to set launch date constraints on the parent object of unidentified debris objects or other unknown spacecraft.

  2. NIR Color vs Launch Date: A 20-year Analysis of Space Weathering Effects on the Boeing 376 Spacecraft

    NASA Astrophysics Data System (ADS)

    Frith, J.; Anz-Meador, P.; Lederer, S.; Cowardin, H.; Buckalew, B.

    The Boeing HS-376 spin stabilized spacecraft was a popular design that was launched continuously into geosynchronous orbit starting in 1980 with the last launch occurring in 2002. Over 50 of the HS-376 buses were produced to fulfill a variety of different communication missions for countries all over the world. The design of the bus is easily approximated as a telescoping cylinder that is covered with solar cells and an Earth facing antenna that is despun at the top of the cylinder. The similarity in design and the number of spacecraft launched over a long period of time make the HS-376 a prime target for studying the effects of solar weathering on solar panels as a function of time. A selection of primarily non-operational HS-376 spacecraft launched over a 20 year time period were observed using the United Kingdom Infrared Telescope on Mauna Kea and multi-band near-infrared photometry produced. Each spacecraft was observed for an entire night cycling through ZYJHK filters and time-varying colors produced to compare near-infrared color as a function of launch date. The resulting analysis shown here may help in the future to set launch date constraints on the parent object of unidentified debris objects or other unknown spacecraft.

  3. Petermann Glacier, North Greenland: Large Ice-Discharge Episodes from 20 Years of Satellite Observations

    NASA Astrophysics Data System (ADS)

    Babiker, M.; Johannessen, O. M.; Miles, M. W.; Miles, V. V.

    2009-12-01

    The major marine-terminating outlet glaciers of Greenland can undergo large mass losses through calving of icebergs and bottom melting from floating ice tongues. Recent observations of outlet glaiers around Greenland have shown that large and rapid changes in solid-ice fluxes are possible. The Petermann glacier in remote northern Greenland is the region’s largest floating-tongue glacier (~70 km by 10 km). In summer 2008 a large calving event was observed, as well as large cracks upstream of the remaining calving front, portending a more massive near-term loss. These observations may herald extraordinary and unprecedented change. However, the long-term variability of calving events and ice velocities are poorly known. Our research goal here is to identify the temporal variability and possible trends in solid-ice flux indicators - variability of the calving front and ice velocity - for Petermann glacier. The methodological approach is observational, based primarily on analysis of 20 years of repetitive satellite data over a period starting from 1990, together with sporadic earlier observations. The multisensor data range from high-resolution optical images from Landsat, SPOT and Terra ASTER and high-resolution synthetic aperture radar (SAR) images from ERS and ENVISAT. These disparate data have been imported, geo-registered and analysed within a Geographic Information System. The following measurements are made: (1) delineating changes in the calving front, (2) estimating the area of glacial ice loss during calving events, and (3) estimating the ice-surface velocity using sequential satellite images. We find evidence of a number of previous calving episodes of similar magnitude to the summer 2008. The ice-velocity estimates compare well with other estimates for particular years, and moreover are relatively consistent during the 20-year period. These findings suggest business-as-usual for Petermann glacier; however, a near-term calving event exceeding those observed

  4. Extracting Binary Orbital Periods Using Timing Analysis of Microlensing Lightcurves

    NASA Astrophysics Data System (ADS)

    Guo, Xinyi; Esin, A.; Di Stefano, R.

    2012-01-01

    Gravitational microlensing events provide unique opportunities to discover and study binaries. A large number of binary lenses have already been found by the microlensing surveys. For the majority of these systems, the binary orbital period is much longer than the duration of the lensing event, so orbital motion can be safely ignored. However, a few lenses have already been discovered that show strong evidence of orbital motion on the timescale of the lensing event. We expect that more such systems will be seen in the future. For binaries whose orbital period is comparable to the event duration, the orbital motion can cause the lensing signal to deviate drastically from that of a static binary lens. The most striking property of such lightcurves is the presence of quasi-periodic features, produced as the source traverses the same regions in the rotating lens plane. Those repeated features contain information about the orbital period of the lens. If this period can be extracted, we immediately learn a lot about the lensing system even without performing the detailed lightcurve modeling. However, the relative transverse motion between the source and the lens significantly complicates the problem of period extraction. To resolve this difficulty, we present a modification to the standard Lomb-Scargle periodogram analysis. We test our method for 6 representative binary lens systems and demonstrate its efficiency in correctly extracting binary orbital periods.

  5. Convergence time towards periodic orbits in discrete dynamical systems.

    PubMed

    San Martín, Jesús; Porter, Mason A

    2014-01-01

    We investigate the convergence towards periodic orbits in discrete dynamical systems. We examine the probability that a randomly chosen point converges to a particular neighborhood of a periodic orbit in a fixed number of iterations, and we use linearized equations to examine the evolution near that neighborhood. The underlying idea is that points of stable periodic orbit are associated with intervals. We state and prove a theorem that details what regions of phase space are mapped into these intervals (once they are known) and how many iterations are required to get there. We also construct algorithms that allow our theoretical results to be implemented successfully in practice.

  6. 20 years of Black Carbon measurements in Germany

    NASA Astrophysics Data System (ADS)

    Kutzner, Rebecca; Quedenau, Jörn; Kuik, Friderike; von Schneidemesser, Erika; Schmale, Julia

    2016-04-01

    Black Carbon (BC) is an important short-lived climate-forcing pollutant contributing to global warming through absorption of sunlight. At the same time, BC, as a component of particulate matter (PM) exerts adverse health effects, like decreased lung function and exacerbated asthma. Globally, anthropogenic emission sources of BC include residential heating, transport, and agricultural fires, while the dominant natural emission sources are wildfires. Despite the various adverse effects of BC, legislation that requires mandatory monitoring of BC concentrations does not currently exist in the European Union. Instead, BC is only indirectly monitored as component of PM10 and PM2.5 (particulate matter with a diameter smaller 10 μm and 2.5 μm). Before the introduction of mandatory PM10 and PM2.5 monitoring in the European Union in 2005 and 2015, respectively, 'black smoke', a surrogate for BC, was a required measurement in Germany from the early 1990s. The annual mean limit value was 14 μg m-3 from 1995 and 8 μg m-3 from 1998 onwards. Many 'black smoke' measurements were stopped in 2004, with the repeal of the regulations obtaining at the time. However, in most German federal states a limited number BC monitoring stations continued to operate. Here we present a synthesis of BC data from 213 stations across Germany covering the period between 1994 and 2014. Due to the lack of a standardized method and respective legislation, the data set is very heterogeneous relying on twelve different measurement methods including chemical, optical, and thermal-optical methods. Stations include locations classified as background, urban-background, industrial and traffic among other types. Raw data in many different formats has been modelled and integrated in a relational database, allowing various options for further data analysis. We highlight results from the year 2009, as it is the year with the largest measurement coverage based on the same measurement method, with 30 stations. In

  7. Logic Model Checking of Time-Periodic Real-Time Systems

    NASA Technical Reports Server (NTRS)

    Florian, Mihai; Gamble, Ed; Holzmann, Gerard

    2012-01-01

    In this paper we report on the work we performed to extend the logic model checker SPIN with built-in support for the verification of periodic, real-time embedded software systems, as commonly used in aircraft, automobiles, and spacecraft. We first extended the SPIN verification algorithms to model priority based scheduling policies. Next, we added a library to support the modeling of periodic tasks. This library was used in a recent application of the SPIN model checker to verify the engine control software of an automobile, to study the feasibility of software triggers for unintended acceleration events.

  8. Oscillating dark energy model in plane symmetric space-time with time periodic varying deceleration parameter

    NASA Astrophysics Data System (ADS)

    She, M.; Jiang, L. P.

    2014-12-01

    In this paper, an oscillating dark energy model is presented in an isotropic but inhomogeneous plane symmetric space-time by considering a time periodic varying deceleration parameter. We find three different types of new solutions which describe different scenarios of oscillating universe. The first two solutions show an oscillating universe with singularities. For the third one, the universe is singularity-free during the whole evolution. Moreover, the Hubble parameter oscillates and keeps positive which explores an interesting possibility to unify the early inflation and late time acceleration of the universe.

  9. Change in newspaper coverage of schizophrenia in Japan over 20-year period.

    PubMed

    Aoki, Ai; Aoki, Yuta; Goulden, Robert; Kasai, Kiyoto; Thornicroft, Graham; Henderson, Claire

    2016-08-01

    In Japan, schizophrenia was renamed in 2002 to reduce the stigma that people with schizophrenia are dangerous. However there has been little research on the potential anti-stigma effect of renaming. The present study aimed to examine whether portrayals of schizophrenia in newspapers as dangerous have been varied across renaming of the disease. To achieve this goal, newspaper articles containing the previous and new Japanese names for schizophrenia, published in the decades before and after the renaming, were identified through the database of the three largest Japanese national broadsheets. Identified articles were divided into two categories: a negative category, including a subcategory "danger"; and a positive category. Articles containing bipolar disorder were adopted as a control. The ratio of the number of articles on schizophrenia and danger to that of bipolar disorder was analysed as a variable of interest. The trend of this ratio was investigated to examine whether portrayals of schizophrenia changed after renaming. The search identified 4677 articles on schizophrenia, 53.0% of which were categorised as negative and 38.9% as danger. The search identified 525 articles on bipolar disorder, 24.6% of which were categorised as negative and 11.2% as danger. There was an increase of the ratio before schizophrenia was renamed (r=0.54, p=0.104), and a significant decrease after renaming (r=-0.69, p=0.028). Fisher's r-to-z transformation demonstrated a significant change in the trend of the ratio across renaming (Z=2.72, p=0.007). Renaming schizophrenia might be associated with mitigation in potentially stigmatised depiction of schizophrenia associated with violence in newspaper reports.

  10. UNEP: Two Decades of Achievement and Challenge. 20 Years.

    ERIC Educational Resources Information Center

    El-Hinnawi, Essam

    This publication highlights major achievements of the United Nations Environment Program (UNEP) activities over the period 1970 to 1990. Chapter 1, "The Stockholm Conference and the Establishment of UNEP," describes the establishment of UNEP. Chapter 2, "The Role of UNEP," covers program development, environment and…

  11. Empirically Enhanced Reflections on 20 Years of Rape Research

    ERIC Educational Resources Information Center

    Koss, Mary P.

    2005-01-01

    Using PsychInfo review of rape and sexual assault publications, the period of greatest fertility coincided with the establishment (1975) and demise (1987) of the National Center for the Prevention and Control of Rape. To document what has been learned and when, the era in which new rape concepts entered the literature is summarized and important…

  12. Antimicrobial-Resistant Escherichia coli Survived in Dust Samples for More than 20 Years

    PubMed Central

    Schulz, Jochen; Ruddat, Inga; Hartung, Jörg; Hamscher, Gerd; Kemper, Nicole; Ewers, Christa

    2016-01-01

    that under particular conditions, dust from farm animal houses can be reservoirs for antimicrobial-resistant E. coli for at least 20 years. The survival strategies that allow E. coli to survive such long periods in environmental samples are not fully understood and could be an interesting research topic for future studies. PMID:27375587

  13. A Developmental Perspective on Alcohol and Youths 16 to 20 Years of Age

    PubMed Central

    Brown, Sandra A.; McGue, Matthew; Maggs, Jennifer; Schulenberg, John; Hingson, Ralph; Swartzwelder, Scott; Martin, Christopher; Chung, Tammy; Tapert, Susan F.; Sher, Kenneth; Winters, Ken C.; Lowman, Cherry; Murphy, Stacia

    2009-01-01

    Late adolescence (ie, 16-20 years of age) is a period characterized by escalation of drinking and alcohol use problems for many and by the onset of an alcohol use disorder for some. This heightened period of vulnerability is a joint consequence of the continuity of risk from earlier developmental stages and the unique neurologic, cognitive, and social changes that occur in late adolescence. We review the normative neurologic, cognitive, and social changes that typically occur in late adolescence, and we discuss the evidence for the impact of these transitions on individual drinking trajectories. We also describe evidence linking alcohol abuse in late adolescence with neurologic damage and social impairments, and we discuss whether these are the bases for the association of adolescent drinking with increased risks of mental health, substance abuse, and social problems in adulthood. Finally, we discuss both the challenges and successes in the treatment and prevention of adolescent drinking problems. PMID:18381495

  14. Intrinsic Periodicity of Time and Nonmaximal Entropy of Universe

    NASA Astrophysics Data System (ADS)

    Nielsen, Holger B.; Ninomiya, Masao

    The universe is certainly not yet in a total thermodynamical equilibrium. Thus some law of special initial conditions is needed. A universe or a system imposed to behave periodically will then require "initial conditions." Those initial conditions will not look like the type we already have, which have been suffered the heat death. In other words, the required initial conditions should not have been obtained the maximal entropy — like a random state. The intrinsic periodicity successfully explains why entropy is not maximal but it fails, phenomenologically, in leading to a constant entropy.

  15. Real-time method of powder diffraction for non-periodic and nearly periodic materials

    SciTech Connect

    Egami, T.; Toby, B.H.; Dmowski, T.W. . Dept. of Materials Science and Engineering); Janot, C. ); Jorgensen, J.D. )

    1989-12-01

    The use of high-energy neutrons from pulsed or hot sources allows the method of atomic pair distribution analysis to be applied to the structural determination of crystalline as well as amorphous solids. This method complements the standard crystallographic methods in studying non-periodic aspects of solids with or without long range order. 14 refs., 3 figs.

  16. 29 CFR 4000.43 - How do I compute a time period?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false How do I compute a time period? 4000.43 Section 4000.43..., ISSUANCE, COMPUTATION OF TIME, AND RECORD RETENTION Computation of Time § 4000.43 How do I compute a time period? (a) In general. If you are computing a time period to which this part applies, whether you...

  17. Burning invariant manifolds in time-periodic and time-aperiodic vortex flows

    NASA Astrophysics Data System (ADS)

    Gowen, Savannah; Solomon, Tom

    2014-11-01

    We present experiments that study reaction fronts in a flow composed of a single, translating vortex. The fronts are produced by the excitable Belousov-Zhabotinsky (BZ) chemical reaction, and the vortex flow is driven magnetohydrodynamically by a radial current in a thin fluid layer above a Nd-Fe-Bo magnet. The magnet is mounted on a pair of perpendicular translation stages, allowing for controlled, two-dimensional movement of the magnet and the resulting vortex. We study reaction fronts that pin to the vortex for time-independent flows (produced by moving the vortex with a constant velocity) and for time-periodic and time-aperiodic flows produced by oscillating the vortex laterally. The steady-state front shape is analyzed in terms of burning invariant manifolds (BIMs) that act as one-way barriers against any propagating reaction fronts. For time independent and time-periodic flows, the location of the BIMs are calculated numerically and are compared with experimental images of the pinned reaction fronts. We investigate extensions of this BIM approach for analyzing fronts in time-aperiodic flows. Supported by NSF Grants DMR-1004744, DMR-1361881 and PHY-1156964.

  18. Periodization

    PubMed Central

    Lorenz, Daniel S.; Reiman, Michael P.; Walker, John C.

    2010-01-01

    Background: Clinicians are constantly faced with the challenge of designing training programs for injured and noninjured athletes that maximize healing and optimize performance. Periodization is a concept of systematic progression—that is, resistance training programs that follow predictable patterns of change in training variables. The strength training literature is abundant with studies comparing periodization schemes on uninjured, trained, and untrained athletes. The rehabilitation literature, however, is scarce with information about how to optimally design resistance training programs based on periodization principles for injured athletes. The purpose of this review is to discuss relevant training variables and methods of periodization, as well as periodization program outcomes. A secondary purpose is to provide an anecdotal framework regarding implementation of periodization principles into rehabilitation programs. Evidence Acquisition: A Medline search from 1979 to 2009 was implemented with the keywords periodization, strength training, rehabilitation, endurance, power, hypertrophy, and resistance training with the Boolean term AND in all possible combinations in the English language. Each author also undertook independent hand searching of article references used in this review. Results: Based on the studies researched, periodized strength training regimens demonstrate improved outcomes as compared to nonperiodized programs. Conclusions: Despite the evidence in the strength training literature supporting periodization programs, there is a considerable lack of data in the rehabilitation literature about program design and successful implementation of periodization into rehabilitation programs. PMID:23015982

  19. 36 CFR 218.10 - Objection time periods and process.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... legal notice of the EA or final EIS in the newspaper of record or the publication date of the notice in... of the EA or final EIS in the newspaper of record or Federal Register (§ 218.5(c)) is the first day of the objection-filing period. (3) The publication date of the legal notice of the EA or final...

  20. Time Periodic Control of a Multi-Blade Helicopter.

    DTIC Science & Technology

    1988-05-01

    motion (13-22). Friedmann and Silverthorn (13) examined the flap-lag motion of a cantilevered rotor blade at arbitrary d, advance ratios. They concluded...Advance Ratio,* NASA SP-352: 25-34 (1974). 13. Friedmann, P. and L. J. Silverthorn . "Aeroelastic Stability of Periodic Systems with Applications to Rotor

  1. Existence, Uniqueness and Asymptotic Stability of Time Periodic Traveling Waves for a Periodic Lotka-Volterra Competition System with Diffusion.

    PubMed

    Zhao, Guangyu; Ruan, Shigui

    2011-06-01

    We study the existence, uniqueness, and asymptotic stability of time periodic traveling wave solutions to a periodic diffusive Lotka-Volterra competition system. Under certain conditions, we prove that there exists a maximal wave speed c(*) such that for each wave speed c ≤ c(*), there is a time periodic traveling wave connecting two semi-trivial periodic solutions of the corresponding kinetic system. It is shown that such a traveling wave is unique modulo translation and is monotone with respect to its co-moving frame coordinate. We also show that the traveling wave solutions with wave speed c < c(*) are asymptotically stable in certain sense. In addition, we establish the nonexistence of time periodic traveling waves for nonzero speed c > c(*).

  2. Existence, Uniqueness and Asymptotic Stability of Time Periodic Traveling Waves for a Periodic Lotka-Volterra Competition System with Diffusion

    PubMed Central

    Zhao, Guangyu; Ruan, Shigui

    2011-01-01

    We study the existence, uniqueness, and asymptotic stability of time periodic traveling wave solutions to a periodic diffusive Lotka-Volterra competition system. Under certain conditions, we prove that there exists a maximal wave speed c* such that for each wave speed c ≤ c*, there is a time periodic traveling wave connecting two semi-trivial periodic solutions of the corresponding kinetic system. It is shown that such a traveling wave is unique modulo translation and is monotone with respect to its co-moving frame coordinate. We also show that the traveling wave solutions with wave speed c < c* are asymptotically stable in certain sense. In addition, we establish the nonexistence of time periodic traveling waves for nonzero speed c > c*. PMID:21572575

  3. Using travel times to simulate multi-dimensional bioreactive transport in time-periodic flows.

    PubMed

    Sanz-Prat, Alicia; Lu, Chuanhe; Finkel, Michael; Cirpka, Olaf A

    2016-04-01

    In travel-time models, the spatially explicit description of reactive transport is replaced by associating reactive-species concentrations with the travel time or groundwater age at all locations. These models have been shown adequate for reactive transport in river-bank filtration under steady-state flow conditions. Dynamic hydrological conditions, however, can lead to fluctuations of infiltration velocities, putting the validity of travel-time models into question. In transient flow, the local travel-time distributions change with time. We show that a modified version of travel-time based reactive transport models is valid if only the magnitude of the velocity fluctuates, whereas its spatial orientation remains constant. We simulate nonlinear, one-dimensional, bioreactive transport involving oxygen, nitrate, dissolved organic carbon, aerobic and denitrifying bacteria, considering periodic fluctuations of velocity. These fluctuations make the bioreactive system pulsate: The aerobic zone decreases at times of low velocity and increases at those of high velocity. For the case of diurnal fluctuations, the biomass concentrations cannot follow the hydrological fluctuations and a transition zone containing both aerobic and obligatory denitrifying bacteria is established, whereas a clear separation of the two types of bacteria prevails in the case of seasonal velocity fluctuations. We map the 1-D results to a heterogeneous, two-dimensional domain by means of the mean groundwater age for steady-state flow in both domains. The mapped results are compared to simulation results of spatially explicit, two-dimensional, advective-dispersive-bioreactive transport subject to the same relative fluctuations of velocity as in the one-dimensional model. The agreement between the mapped 1-D and the explicit 2-D results is excellent. We conclude that travel-time models of nonlinear bioreactive transport are adequate in systems of time-periodic flow if the flow direction does not change.

  4. Using travel times to simulate multi-dimensional bioreactive transport in time-periodic flows

    NASA Astrophysics Data System (ADS)

    Sanz-Prat, Alicia; Lu, Chuanhe; Finkel, Michael; Cirpka, Olaf A.

    2016-04-01

    In travel-time models, the spatially explicit description of reactive transport is replaced by associating reactive-species concentrations with the travel time or groundwater age at all locations. These models have been shown adequate for reactive transport in river-bank filtration under steady-state flow conditions. Dynamic hydrological conditions, however, can lead to fluctuations of infiltration velocities, putting the validity of travel-time models into question. In transient flow, the local travel-time distributions change with time. We show that a modified version of travel-time based reactive transport models is valid if only the magnitude of the velocity fluctuates, whereas its spatial orientation remains constant. We simulate nonlinear, one-dimensional, bioreactive transport involving oxygen, nitrate, dissolved organic carbon, aerobic and denitrifying bacteria, considering periodic fluctuations of velocity. These fluctuations make the bioreactive system pulsate: The aerobic zone decreases at times of low velocity and increases at those of high velocity. For the case of diurnal fluctuations, the biomass concentrations cannot follow the hydrological fluctuations and a transition zone containing both aerobic and obligatory denitrifying bacteria is established, whereas a clear separation of the two types of bacteria prevails in the case of seasonal velocity fluctuations. We map the 1-D results to a heterogeneous, two-dimensional domain by means of the mean groundwater age for steady-state flow in both domains. The mapped results are compared to simulation results of spatially explicit, two-dimensional, advective-dispersive-bioreactive transport subject to the same relative fluctuations of velocity as in the one-dimensional model. The agreement between the mapped 1-D and the explicit 2-D results is excellent. We conclude that travel-time models of nonlinear bioreactive transport are adequate in systems of time-periodic flow if the flow direction does not change.

  5. Europe Unveils 20-Year Plan for Brilliant Future in Astronomy

    NASA Astrophysics Data System (ADS)

    2008-11-01

    Astronomy is enjoying a golden age of fundamental, exciting discoveries. Europe is at the forefront, thanks to 50 years of progress in cooperation. To remain ahead over the next two to three decades, Europe must prioritise and coordinate the investment of its financial and human resources even more closely. The ASTRONET network, backed by the entire European scientific community, supported by the European Commission, and coordinated by the CNRS, today presents its Roadmap for a brilliant future for European astronomy. ESO's European Extremely Large Telescope is ranked as one of two top-priority large ground-based projects. Astronet and the E-ELT ESO PR Photo 43a/08 The E-ELT Europe is a leader in astronomy today, with the world's most successful optical observatory, ESO's Very Large Telescope, and cutting-edge facilities in radio astronomy and in space. In an unprecedented effort demonstrating the potential of European scientific cooperation, all of European astronomy is now joining forces to define the scientific challenges for the future and construct a common plan to address them in a cost-effective manner. In 2007, a top-level Science Vision was prepared to assess the most burning scientific questions over the next quarter century, ranging from dark energy to life on other planets. European astronomy now presents its Infrastructure Roadmap, a comprehensive 20-year plan to coordinate national and community investments to meet these challenges in a cost-effective manner. The Roadmap not only prioritises the necessary new frontline research facilities from radio telescopes to planetary probes, in space and on the ground, but also considers such key issues as existing facilities, human resources, ICT infrastructure, education and outreach, and cost -- of operations as well as construction. This bold new initiative -- ASTRONET -- was created by the major European funding agencies with support from the European Commission and is coordinated by the National Institute

  6. Children's Rights and Youth Justice: 20 Years of No Progress

    ERIC Educational Resources Information Center

    Smith, Roger

    2010-01-01

    The adoption of the United Nations Convention on the Rights of the Child (UNCRC) in 1989 and its ratification by the UK government two years later came at a time of considerable progress in youth justice. The Convention itself set clear standards of treatment, in terms of both processes and disposals, which appeared at the time to provide positive…

  7. Trends of tropical tropospheric ozone from 20 years of European satellite measurements and perspectives for the Sentinel-5 Precursor

    NASA Astrophysics Data System (ADS)

    Heue, Klaus-Peter; Coldewey-Egbers, Melanie; Delcloo, Andy; Lerot, Christophe; Loyola, Diego; Valks, Pieter; van Roozendael, Michel

    2016-10-01

    In preparation of the TROPOMI/S5P launch in early 2017, a tropospheric ozone retrieval based on the convective cloud differential method was developed. For intensive tests we applied the algorithm to the total ozone columns and cloud data of the satellite instruments GOME, SCIAMACHY, OMI, GOME-2A and GOME-2B. Thereby a time series of 20 years (1995-2015) of tropospheric column ozone was generated. To have a consistent total ozone data set for all sensors, one common retrieval algorithm, namely GODFITv3, was applied and the L1 reflectances were also soft calibrated. The total ozone columns and the cloud data were input into the tropospheric ozone retrieval. However, the tropical tropospheric column ozone (TCO) for the individual instruments still showed small differences and, therefore, we harmonised the data set. For this purpose, a multilinear function was fitted to the averaged difference between SCIAMACHY's TCO and those from the other sensors. The original TCO was corrected by the fitted offset. GOME-2B data were corrected relative to the harmonised data from OMI and GOME-2A. The harmonisation leads to a better agreement between the different instruments. Also, a direct comparison of the TCO in the overlapping periods proves that GOME-2A agrees much better with SCIAMACHY after the harmonisation. The improvements for OMI were small. Based on the harmonised observations, we created a merged data product, containing the TCO from July 1995 to December 2015. A first application of this 20-year record is a trend analysis. The tropical trend is 0.7 ± 0.12 DU decade-1. Regionally the trends reach up to 1.8 DU decade-1 like on the African Atlantic coast, while over the western Pacific the tropospheric ozone declined over the last 20 years with up to 0.8 DU decade-1. The tropical tropospheric data record will be extended in the future with the TROPOMI/S5P data, where the TCO is part of the operational products.

  8. A 20-year experience in unilateral cleft lip repair: From Millard to the triple unilimb Z-plasty technique

    PubMed Central

    Rossell-Perry, Percy

    2016-01-01

    Background: This study describes a 20-year experience of treating patients with unilateral cleft lip. During this time, various techniques were used including Millard's technique and its modification and two types of geometrically designed procedures. The study objective was to compare surgical outcomes of different surgical techniques for unilateral cleft lip repair. Materials and Methods: This is a retrospective audit of outcomes after unilateral cleft lip repair performed by a single surgeon since 1995. Of the 827 patients who underwent surgery, 277 met the criterion of having anthropometric measurements performed ≥1 year postoperatively. The patients were stratified into three groups according to cleft severity: incomplete, complete with less deficiency (3–6 mm difference between cleft and non-cleft lip height) and complete with more deficiency (>6 mm difference between cleft and non-cleft lip height). Anthropometric measurements, scar assessment and complications were recorded. Results: There were no differences in outcomes between Millard and Reichert-Millard techniques for incomplete unilateral cleft lip. For complete unilateral cleft lip and less tissue deficiency, lip symmetry was better using upper rotation advancement plus double unilimb Z-plasty than the Reichert-Millard technique. For complete unilateral cleft lip and more tissue deficiency, lip symmetry was better after triple unilimb Z-plasty than after upper rotation advancement plus double unilimb Z-plasty. Conclusions: We presented a 20-year experience performing unilateral cleft lip repair. An individualised classification system with corresponding surgical techniques was successfully used during this period. The individualised surgical protocol used in this study allowed us to achieve improved surgical outcomes. PMID:28216814

  9. Serial extraction: 20 years of follow-up

    PubMed Central

    de ALMEIDA, Renato Rodrigues; de ALMEIDA, Marcio Rodrigues; OLTRAMARI-NAVARRO, Paula Vanessa Pedron; CONTI, Ana Cláudia de Castro Ferreira; NAVARRO, Ricardo de Lima; de SOUZA, Karen Regina Siqueira

    2012-01-01

    This paper reports a case treated by a serial extraction program at the mixed dentition stage followed by a corrective orthodontic treatment, with a long-term follow-up period. Twenty years after the interceptive treatment, a harmonious face was observed along with treatment stability in the anterior posterior direction, deep overbite (which has been mentioned as a disadvantage of the serial extraction program), and a small relapse of anterior tooth crowding. All these conditions have been regarded as normal occurrences for most orthodontic treatments with a long-term follow-up period. This case report demonstrated that the establishment of a serial extraction protocol determined relevant esthetic changes that afforded an improvement of the patient's self-esteem, with a positive social impact. Furthermore, the low cost of this protocol permits the use of this therapy with underprivileged populations. It is important to emphasize that an early correction of tooth crowding by this protocol does not guarantee stability, but small relapses do not invalidate its accomplishment. PMID:23032213

  10. Transient aggregation and long-time diffusion of bacterial suspensions in time periodic flows

    NASA Astrophysics Data System (ADS)

    Qin, Boyang; Winter, Rebecca; Gurjar, Madhura; Gagnon, David; Patteson, Alison; Arratia, Paulo

    2016-11-01

    In this talk, the transport dynamics of swimming bacteria in time-periodic flows is investigated in experiments and simulations. Experiments are performed by introducing swimming bacteria (Vibrio cholerae) in a low Reynolds number, two-dimensional flow driven electromagnetically. We observe two distinct transport regimes: (i) entrapment of bacteria inside vortex and near elliptic points and (ii) aggregation and subsequent transport along the flow manifolds. These time-dependent behaviors are set by the interaction between swimmer kinematics (e.g. speed, tumbling frequency, etc) and flow properties. Numerical simulation using a stochastic Langevin model are able to capture the main experimental results including the entrapment of bacteria near elliptic points and the rapid spreading along manifolds. Results show a significant reduction in long-time effective diffusion of the swimmer as vortex strength is increased. The conditions for bacterial entrapment in vortex flows are discussed.

  11. 20 Years Later: Dynamics of the School-College Partnership

    ERIC Educational Resources Information Center

    Heimann, Revital

    2015-01-01

    This descriptive study examined the dynamics of partnership over time between a training school and a college of education. Its purpose was to provide a deeper understanding of the dynamics of collaboration within the context of the partnership between the school and the college. The dynamics of the changes occurring in this collaboration over a…

  12. Future Economics of Liver Transplantation: A 20-Year Cost Modeling Forecast and the Prospect of Bioengineering Autologous Liver Grafts.

    PubMed

    Habka, Dany; Mann, David; Landes, Ronald; Soto-Gutierrez, Alejandro

    2015-01-01

    During the past 20 years liver transplantation has become the definitive treatment for most severe types of liver failure and hepatocellular carcinoma, in both children and adults. In the U.S., roughly 16,000 individuals are on the liver transplant waiting list. Only 38% of them will receive a transplant due to the organ shortage. This paper explores another option: bioengineering an autologous liver graft. We developed a 20-year model projecting future demand for liver transplants, along with costs based on current technology. We compared these cost projections against projected costs to bioengineer autologous liver grafts. The model was divided into: 1) the epidemiology model forecasting the number of wait-listed patients, operated patients and postoperative patients; and 2) the treatment model forecasting costs (pre-transplant-related costs; transplant (admission)-related costs; and 10-year post-transplant-related costs) during the simulation period. The patient population was categorized using the Model for End-Stage Liver Disease score. The number of patients on the waiting list was projected to increase 23% over 20 years while the weighted average treatment costs in the pre-liver transplantation phase were forecast to increase 83% in Year 20. Projected demand for livers will increase 10% in 10 years and 23% in 20 years. Total costs of liver transplantation are forecast to increase 33% in 10 years and 81% in 20 years. By comparison, the projected cost to bioengineer autologous liver grafts is $9.7M based on current catalog prices for iPS-derived liver cells. The model projects a persistent increase in need and cost of donor livers over the next 20 years that's constrained by a limited supply of donor livers. The number of patients who die while on the waiting list will reflect this ever-growing disparity. Currently, bioengineering autologous liver grafts is cost prohibitive. However, costs will decline rapidly with the introduction of new manufacturing

  13. Environmental accounting as a management tool in the Mediterranean context: the Spanish economy during the last 20 years.

    PubMed

    Lomas, Pedro L; Alvarez, Sergio; Rodríguez, Marta; Montes, Carlos

    2008-07-01

    Although human presence is one of the main characteristics of the Mediterranean identity since ancient times, a false dialectic between conservation and social-economic development has emerged in recent decades. On the one hand, an economic growth policy is taken as the paradigm of social-economic development; on the other hand, there is a multi-scale conservation policy, in which natural protected areas, as patches of preserved nature, are used as one of the main tools to deal with the challenge of sustainability. The Mediterranean Basin is the habitat of many unique species and one of the 25 main biodiversity hotspots in the world, and as a consequence a strong conservation policy has been used to protect environmental values. At the same time, Mediterranean countries are deeply involved in promoting strong economic growth policies, which are not always compatible with environmental ones. In this paper, Spain has been studied as one model of this situation. Due to political reasons, Spanish economic growth and conservationist policies were pursued together during the last 20 years. As a result, Spain owns one of the largest networks of natural protected areas in Western Europe, and at the same time it has experienced one of the strongest periods of economic growths in the European and Mediterranean context during the 1980s and 1990s. An historical series of resource use in five annual periods in the last 20 years of conservation policy, and the effects on the preservation of natural capital have been investigated by means of the eMergy (spelled with an 'm') synthesis approach, which was used to characterize the flow of environmental services supplied by ecosystems, but not in monetary terms. This study shows that Spain is becoming less self-sufficient and more inefficient in resource use, comprehensively measured in eMergy terms. A large part of Spain's economy depends on imported goods and services, and most economic activities are based on tourist services and

  14. Lingual access for third molar surgery: a 20-year retrospective audit.

    PubMed

    Moss, C E; Wake, M J

    1999-08-01

    We describe a technique for obtaining lingual access for the insertion of a wide metal retractor to protect the lingual nerve from accidental damage during third molar surgery. We also report an audit of a single practice over a 20-year period using the technique described. The approach involves raising soft tissues on the lingual side of the lower third molar tooth to allow insertion of a broad Hovell's lingual retractor. We conclude that raising lingual tissues to form a wide tension-free flap and inserting a specifically designed retractor does not increase the incidence of lingual nerve morbidity. Indeed, the overall incidence of lingual nerve damage was particularly low compared with those in other published series.

  15. Pulmonary gas transfer 20 years after pneumonectomy for pulmonary tuberculosis.

    PubMed Central

    Gimeno, F; Kraan, J K; Orie, N G; Peset, R

    1977-01-01

    The changes in pulmonary function after pneumonectomy in 13 patients with pulmonary tuberculosis have been studied. The data at the time of two follow-up studies are compared with those obtained before the pneumonectomy. The first follow-up was carried out between 5 and 30 months postoperatively and the second between 20 and 24 years later. The results of this second follow-up show a relatively normal arterial oxygen saturation and gas transfer factor but an increased residual volume which cannot be explained by increasing age alone. PMID:841538

  16. My 20 years of experience in the human factors field

    SciTech Connect

    Carnino, A. )

    1992-01-01

    My first encounter with human factors happened in early 1973: I was performing a reliability assessment of the safety injection system of the Fessenheim reactor, and I found that the operators had to switch to the recirculation phase manually and had only 6 min between the low and low-low level alarm indicating that the water tank was empty. It of course led us to replace this manual action by an automatic positioning for the recirculation phase. In July of the same year, I attended a North Atlantic Treaty Organization workshop in Liverpool on reliability assessment, and I met Alan Swain from the United States and Jens Rasmussen from Denmark. During the long rainy evenings of the seminar, we had time to discuss human errors and human factors, and that was the beginning of a very fruitful collaboration between us. I realized then the complexity of the problem. Quantification needs were obvious for reliability and risk assessment studies, but, at the same time, there were needs for better understanding of human behavior and the mechanisms that could lead to human errors. Knowledge of the man-machine interface also seemed very poor, although some basic ergonomic rules were available and could be applied. But a major problem was the lack of data.

  17. Load Balancing Using Time Series Analysis for Soft Real Time Systems with Statistically Periodic Loads

    NASA Technical Reports Server (NTRS)

    Hailperin, Max

    1993-01-01

    This thesis provides design and analysis of techniques for global load balancing on ensemble architectures running soft-real-time object-oriented applications with statistically periodic loads. It focuses on estimating the instantaneous average load over all the processing elements. The major contribution is the use of explicit stochastic process models for both the loading and the averaging itself. These models are exploited via statistical time-series analysis and Bayesian inference to provide improved average load estimates, and thus to facilitate global load balancing. This thesis explains the distributed algorithms used and provides some optimality results. It also describes the algorithms' implementation and gives performance results from simulation. These results show that our techniques allow more accurate estimation of the global system load ing, resulting in fewer object migration than local methods. Our method is shown to provide superior performance, relative not only to static load-balancing schemes but also to many adaptive methods.

  18. Themes, Orientations, Synergies and a Shared Agenda: The First 20?Years of the SEDA Series of Books

    ERIC Educational Resources Information Center

    Pickford, Ruth; Brown, Sally

    2013-01-01

    Over 20?years, 25 books have been published to date in the SEDA series, and this review article aims to analyse the ways in which books within the series have contributed to thinking in higher education pedagogy over this time. We have approached the texts through three lenses, analysing them chronologically, thematically and by the orientation of…

  19. Insights from 20 years of bacterial genome sequencing.

    PubMed

    Land, Miriam; Hauser, Loren; Jun, Se-Ran; Nookaew, Intawat; Leuze, Michael R; Ahn, Tae-Hyuk; Karpinets, Tatiana; Lund, Ole; Kora, Guruprased; Wassenaar, Trudy; Poudel, Suresh; Ussery, David W

    2015-03-01

    Since the first two complete bacterial genome sequences were published in 1995, the science of bacteria has dramatically changed. Using third-generation DNA sequencing, it is possible to completely sequence a bacterial genome in a few hours and identify some types of methylation sites along the genome as well. Sequencing of bacterial genome sequences is now a standard procedure, and the information from tens of thousands of bacterial genomes has had a major impact on our views of the bacterial world. In this review, we explore a series of questions to highlight some insights that comparative genomics has produced. To date, there are genome sequences available from 50 different bacterial phyla and 11 different archaeal phyla. However, the distribution is quite skewed towards a few phyla that contain model organisms. But the breadth is continuing to improve, with projects dedicated to filling in less characterized taxonomic groups. The clustered regularly interspaced short palindromic repeats (CRISPR)-Cas system provides bacteria with immunity against viruses, which outnumber bacteria by tenfold. How fast can we go? Second-generation sequencing has produced a large number of draft genomes (close to 90 % of bacterial genomes in GenBank are currently not complete); third-generation sequencing can potentially produce a finished genome in a few hours, and at the same time provide methlylation sites along the entire chromosome. The diversity of bacterial communities is extensive as is evident from the genome sequences available from 50 different bacterial phyla and 11 different archaeal phyla. Genome sequencing can help in classifying an organism, and in the case where multiple genomes of the same species are available, it is possible to calculate the pan- and core genomes; comparison of more than 2000 Escherichia coli genomes finds an E. coli core genome of about 3100 gene families and a total of about 89,000 different gene families. Why do we care about bacterial genome

  20. Assessment of benthic changes during 20 years of monitoring the Mexican Salina Cruz Bay.

    PubMed

    González-Macías, C; Schifter, I; Lluch-Cota, D B; Méndez-Rodríguez, L; Hernández-Vázquez, S

    2009-02-01

    In this work a non-parametric multivariate analysis was used to assess the impact of metals and organic compounds in the macro infaunal component of the mollusks benthic community using surface sediment data from several monitoring programs collected over 20 years in Salina Cruz Bay, Mexico. The data for benthic mollusks community characteristics (richness, abundance and diversity) were linked to multivariate environmental patterns, using the Alternating Conditional Expectations method to correlate the biological measurements of the mollusk community with the physicochemical properties of water and sediments. Mollusks community variation is related to environmental characteristics as well as lead content. Surface deposit feeders are increasing their relative density, while subsurface deposit feeders are decreasing with respect to time, these last are expected to be more related with sediment and more affected then by its quality. However gastropods with predatory carnivore as well as chemosymbiotic deposit feeder bivalves have maintained their relative densities along time.

  1. [A glaucoma follow-up of 1500 persons over 20 years].

    PubMed

    Fitoussi, Y; Corbe, C; Hamard, H; Perdriel, G

    1988-01-01

    The parameters of glaucoma risk have been compiled and computer processed on 1,571 patients during 20 years at the C.P.E.M.P.N. (Medical Evaluation Center for the Aeronautic Staff) of Paris. The goal of this study is to follow in real time the évolution of these parameters and to determine their physiological variations across time in terms of age and professional categories. An average intra-ocular pressure of 15.1 mmHg as well as hypertonia and glaucoma percentages respectively of 3.88% and 0.6% have been recorded in this study. These results were below the results of other previous surveys due to the greater age range of our study the youngest being 15 years old. There was no significant difference among pilots and non pilots. The optic disc examination was not decisive for diagnostic screening.

  2. Cytochrome P4501A biomarker indication of oil exposure in harlequin ducks up to 20 years after the Exxon Valdez oil spill.

    PubMed

    Esler, Daniel; Trust, Kimberly A; Ballachey, Brenda E; Iverson, Samuel A; Lewis, Tyler L; Rizzolo, Daniel J; Mulcahy, Daniel M; Miles, A Keith; Woodin, Bruce R; Stegeman, John J; Henderson, John D; Wilson, Barry W

    2010-05-01

    Hydrocarbon-inducible cytochrome P4501A (CYP1A) expression was measured, as ethoxyresorufin-O-deethylase (EROD) activity, in livers of wintering harlequin ducks (Histrionicus histrionicus) captured in areas of Prince William Sound, Alaska, USA, oiled by the 1989 Exxon Valdez spill and in birds from nearby unoiled areas, during 2005 to 2009 (up to 20 years following the spill). The present work repeated studies conducted in 1998 that demonstrated that in harlequin ducks using areas that received Exxon Valdez oil, EROD activity was elevated nearly a decade after the spill. The present findings strongly supported the conclusion that average levels of hepatic EROD activity were higher in ducks from oiled areas than those from unoiled areas during 2005 to 2009. This result was consistent across four sampling periods; furthermore, results generated from two independent laboratories using paired liver samples from one of the sampling periods were similar. The EROD activity did not vary in relation to age, sex, or body mass of individuals, nor did it vary strongly by season in birds collected early and late in the winter of 2006 to 2007, indicating that these factors did not confound inferences about observed differences between oiled and unoiled areas. We interpret these results to indicate that harlequin ducks continued to be exposed to residual Exxon Valdez oil up to 20 years after the original spill. This adds to a growing body of literature suggesting that oil spills have the potential to affect wildlife for much longer time frames than previously assumed.

  3. Wine Consumption and 20-Year Mortality Among Late-Life Moderate Drinkers

    PubMed Central

    Holahan, Charles J.; Schutte, Kathleen K.; Brennan, Penny L.; North, Rebecca J.; Holahan, Carole K.; Moos, Bernice S.; Moos, Rudolf H.

    2012-01-01

    Objective: This study examined level of wine consumption and total mortality among 802 older adults ages 55–65 at baseline, controlling for key sociodemographic, behavioral, and health status factors. Despite a growing consensus that moderate alcohol consumption is associated with reduced total mortality, whether wine consumption provides an additional, unique protective effect is unresolved. Method: Participants were categorized in three subsamples: abstainers, high-wine-consumption moderate drinkers, and low-wine-consumption moderate drinkers. Alcohol consumption, sociodemographic factors, health behavior, and health problems were assessed at baseline; total mortality was indexed across an ensuing 20-year period. Results: After adjusting for all covariates, both high-wine-consumption and low-wine-consumption moderate drinkers showed reduced mortality risks compared with abstainers. Further, compared with moderate drinkers for whom a high proportion of ethanol came from wine, those for whom a low proportion of ethanol came from wine were older, were more likely to be male, reported more health problems, were more likely to be tobacco smokers, scored lower on socioeconomic status, and (statistical trend) reported engaging in less physical activity. Controlling only for overall ethanol consumption, compared with moderate drinkers for whom a high proportion of ethanol came from wine, those for whom a low proportion of ethanol came from wine showed a substantially increased 20-year mortality risk of 85%. However, after controlling for all covariates, the initial mortality difference associated with wine consumption was no longer significant. Conclusions: Among older adults who are moderate drinkers, the apparent unique effects of wine on longevity may be explained by confounding factors correlated with wine consumption. PMID:22152665

  4. The timing behavior of magnetar Swift J1822.3-1606: timing noise or a decreasing period derivative?

    NASA Astrophysics Data System (ADS)

    Tong, Hao; Xu, Ren-Xin

    2013-10-01

    The different timing results of the magnetar Swift J1822.3-1606 are analyzed and understood theoretically. It is noted that different timing solutions are caused not only by timing noise, but also because the period derivative is decreasing after the outburst. Both the decreasing period derivative and the large timing noise may originate from wind braking associated with the magnetar. Future timing of Swift J1822.3-1606 will help clarify whether or not its period derivative is decreasing with time.

  5. Load Balancing Using Time Series Analysis for Soft Real Time Systems with Statistically Periodic Loads

    NASA Technical Reports Server (NTRS)

    Hailperin, M.

    1993-01-01

    This thesis provides design and analysis of techniques for global load balancing on ensemble architectures running soft-real-time object-oriented applications with statistically periodic loads. It focuses on estimating the instantaneous average load over all the processing elements. The major contribution is the use of explicit stochastic process models for both the loading and the averaging itself. These models are exploited via statistical time-series analysis and Bayesian inference to provide improved average load estimates, and thus to facilitate global load balancing. This thesis explains the distributed algorithms used and provides some optimality results. It also describes the algorithms' implementation and gives performance results from simulation. These results show that the authors' techniques allow more accurate estimation of the global system loading, resulting in fewer object migrations than local methods. The authors' method is shown to provide superior performance, relative not only to static load-balancing schemes but also to many adaptive load-balancing methods. Results from a preliminary analysis of another system and from simulation with a synthetic load provide some evidence of more general applicability.

  6. Sex differences in schizophrenia and other psychotic disorders: a 20-year longitudinal study of psychosis and recovery.

    PubMed

    Grossman, Linda S; Harrow, Martin; Rosen, Cherise; Faull, Robert; Strauss, Gregory P

    2008-01-01

    This longitudinal study was designed to provide data on sex differences in the course of schizophrenia and other psychotic disorders. Ninety-seven participants (43 women and 54 men) were assessed during index hospitalization when they were in the acute phase of illness and then reassessed prospectively at 6 consecutive follow-ups over a 20-year period. Patients were evaluated by a series of standardized measures on many aspects of illness including the presence of psychosis, global outcome, and rate of recovery. When women were compared to men in this sample, the data demonstrated a lower percentage of psychotic activity for women over the course of illness (significant at the 7.5- and 20-year follow-ups), and a significant improvement in psychotic activity over 20 years for women (P < .05), but not for men. In addition, women showed significantly better global functioning (P < .05) at 3 of the 6 follow-ups (the 2-, 7.5-, and 10-year follow-ups). Significantly higher percentages (P < .05) of women were in recovery at 2 of the 6 follow-up years (the 2- and 10-year follow-ups). Cumulatively, 61% of the women with schizophrenia showed a period of recovery at some point during the 20-year period compared to 41% of the men. The sex difference patterns were similar for patients with schizophrenia and for those with other types of psychotic disorders. Sex differences in this sample were specifically not attributable to differences in age of onset or premorbid developmental achievements.

  7. Observation of asteroid 2013 TV135 supports my idea that a new impaction will come in 20 years

    NASA Astrophysics Data System (ADS)

    Cao, Dayong

    2014-03-01

    Asteroid 2013 TV135 who will impact in 2023 was newly discovered by Ukrainian astronomers in 2013. It supports my idea that a new impaction will come in 20 years. http://www.nasa.gov/mission_pages/asteroids/news/asteroid20131017.html, http://meetings.aps.org/link/BAPS.2011.DFD.LA.24, http://meetings.aps.org/link/BAPS.2012.APR.K1.78, http://meetings.aps.org/link/BAPS.2013.APR.S2.14. The Sun's companion-dark hole, which is made of dark matter seasonal took its dark comets belt, dark matter, dark lives, and the pressed asteroids belt to impact near our earth. These impactions and dark matter's killers caused seasonal extinctions and produced new species. By many dark comets and asteroids impacting, the dark impaction model is a high probability impaction model; the impaction would not change the orbit of the invisible dark hole, so that it could keep accurate periodicity impactions. With the space-time center, the dark hole system is a negative Einstein's model by ``mass-energy coordinate.'' Sun and Dark hole build up the balance system. Through studying the model, the rule of the impaction can be calculated. Avoid Earth Extinction Association.

  8. Split ileostomy and ileocolostomy for Crohn's disease of the colon and ulcerative colitis: a 20 year survey.

    PubMed Central

    Harper, P H; Truelove, S C; Lee, E C; Kettlewell, M G; Jewell, D P

    1983-01-01

    The clinical course of 140 patients who have had a split ileostomy for ulcerative colitis or colonic Crohn's disease over a 20 year period is reported. In 37 patients with ulcerative colitis there was no sustained improvement. In the 102 patients with Crohn's disease there was an immediate clinical improvement in 95, which was sustained in 65. Thirty patients have subsequently required a proctocolectomy for persistent inflammation, and 28 are still defunctioned. Bowel continuity was restored after 61 split ileostomies and in 44 patients intestinal continuity remains intact at the present time (mean follow up since closure = 62.5 months, range 0-231 months). It is concluded that a split ileostomy is a safe conservative operation producing at least temporary improvement in severely ill and malnourished patients with Crohn's colitis, and that if a subsequent resection becomes necessary it may be less extensive than was thought applicable at the initial operation. In 27 patients a resection has not been required. PMID:6852621

  9. Echoes of Bedford: a 20-year social psychology memoir on participatory action research hatched behind bars.

    PubMed

    Fine, Michelle

    2013-11-01

    Responding to Martin Luther King Jr.'s 1968 address at the American Psychological Association calling for a psychology that would educate Whites about racial injustice, this article challenges the widening epistemological gap between those who suffer from inequality and those who conduct social policy research on inequality. In this 20-year memoir on the echoes of a single piece of participatory policy research, Changing Minds: The Impact of College in a Maximum-Security Prison (Fine et al., 2001), readers are invited to explore how deep critical participation by a collaborative team of university and prisoner researchers has facilitated theoretical and methodological complexity, enhanced contextual and construct validity, thickened commitments to ethics and action, and fueled the political sustainability and generalizability of the findings over time and space.

  10. Unintended compositional changes in genetically modified (GM) crops: 20 years of research.

    PubMed

    Herman, Rod A; Price, William D

    2013-12-04

    The compositional equivalency between genetically modified (GM) crops and nontransgenic comparators has been a fundamental component of human health safety assessment for 20 years. During this time, a large amount of information has been amassed on the compositional changes that accompany both the transgenesis process and traditional breeding methods; additionally, the genetic mechanisms behind these changes have been elucidated. After two decades, scientists are encouraged to objectively assess this body of literature and determine if sufficient scientific uncertainty still exists to continue the general requirement for these studies to support the safety assessment of transgenic crops. It is concluded that suspect unintended compositional effects that could be caused by genetic modification have not materialized on the basis of this substantial literature. Hence, compositional equivalence studies uniquely required for GM crops may no longer be justified on the basis of scientific uncertainty.

  11. Climate correlates of 20 years of trophic changes in a high-elevation riparian system

    USGS Publications Warehouse

    Martin, T.E.

    2007-01-01

    The consequences of climate change for ecosystem structure and function remain largely unknown. Here, I examine the ability of climate variation to explain long-term changes in bird and plant populations, as well as trophic interactions in a high-elevation riparian system in central Arizona, USA, based on 20 years of study. Abundances of dominant deciduous trees have declined dramatically over the 20 years, correlated with a decline in overwinter snowfall. Snowfall can affect overwinter presence of elk, whose browsing can significantly impact deciduous tree abundance. Thus, climate may affect the plant community indirectly through effects on herbivores, but may also act directly by influencing water availability for plants. Seven species of birds were found to initiate earlier breeding associated with an increase in spring temperature across years. The advance in breeding time did not affect starvation of young or clutch size. Earlier breeding also did not increase the length of the breeding season for single-brooded species, but did for multi-brooded species. Yet, none of these phenology-related changes was associated with bird population trends. Climate had much larger consequences for these seven bird species by affecting trophic levels below (plants) and above (predators) the birds. In particular, the climate-related declines in deciduous vegetation led to decreased abundance of preferred bird habitat and increased nest predation rates. In addition, summer precipitation declined over time, and drier summers also were further associated with greater nest predation in all species. The net result was local extinction and severe population declines in some previously common bird species, whereas one species increased strongly in abundance, and two species did not show clear population changes. These data indicate that climate can alter ecosystem structure and function through complex pathways that include direct and indirect effects on abundances and interactions

  12. Sport and infectious risk: a systematic review of the literature over 20 years.

    PubMed

    Grosset-Janin, A; Nicolas, X; Saraux, A

    2012-11-01

    The development of sports activities promoted as a health factor should not hide the increased risk for diseases, more particularly infections. A review of articles made over the last 20 years was made with a descriptive epidemiological purpose. The most marked risk is skin infection with methicillin-resistant community acquired Staphylococcus aureus (27.4% of the articles), followed by Tinea corporis and capitis (13.7%), and leptospirosis (11.7%). The risk of blood-borne infection seems low, and articles are rare (3.9%). The risk of disease with respiratory transmission (measles, meningococcal meningitis) must be taken into account. The effect of physical activity on the immune system depends on the type and duration of the work out: it seems to be beneficial for a workout of a moderate intensity, and deleterious for a sustained acute work out, or a period of intensive training. These periods of protection or susceptibility to infections are described as "open window" and "J curve". The only recommendations for prevention of sport-related infections arise from the frequency of skin infections and the severity of blood-borne infections. These recommendations are published by American and international sports authorities. The specificity of athletes' management is due to imperatives of competitiveness (maintaining physical performance) and the necessity of temporary eviction from sports, in case of contagiousness. The athletes must make sure their recommended vaccinations are up-to-date.

  13. Eastern Mediterranean Health Journal (EMHJ): a 20-year overview (1995-2014).

    PubMed

    Mandil, A; Curlet, F; El-Din, H Nour; Abu-Saleh, N; Soliman, M

    2016-11-02

    The EMHJ was established in 1995 to provide a peer-reviewed platform for health professionals to share their research with the scientific community. The objective of this review was to examine EMR public health research trends, as reflected by EMHJ publications in 20 years (1995-2014), through secondary data analysis. Published articles were categorized according to EMR strategic priority areas (93%), i.e. health systems strengthening (25%); reproductive and child health (22%); communicable diseases (26%); noncommunicable diseases (25%); emergency preparedness (1.5%). Most papers were original research articles (85 %), published in English (94 %), but just over half (52 %) mentioned obtaining a form of ethical clearance in the text. Six countries had each over 100 papers published during the study period, i.e. Iran, Egypt, Saudi Arabia, Jordan, Iraq, Pakistan. Half EMHJ publications during this period came from 4 countries only (Iran, Egypt, Saudi Arabia, Jordan), which calls for further study to evaluate why other EMR nations are less well represented and how to encourage greater contribution from them over the coming years.

  14. 14 CFR 135.273 - Duty period limitations and rest time requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... time, using Coordinated Universal Time or local time, that begins at midnight and ends 24 hours later... calculated using either Coordinated Universal Time or local time to reflect the total elapsed time. Flight... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Duty period limitations and rest...

  15. 14 CFR 135.273 - Duty period limitations and rest time requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... time, using Coordinated Universal Time or local time, that begins at midnight and ends 24 hours later... calculated using either Coordinated Universal Time or local time to reflect the total elapsed time. Flight... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Duty period limitations and rest...

  16. 14 CFR 135.273 - Duty period limitations and rest time requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... time, using Coordinated Universal Time or local time, that begins at midnight and ends 24 hours later... calculated using either Coordinated Universal Time or local time to reflect the total elapsed time. Flight... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Duty period limitations and rest...

  17. 14 CFR 135.273 - Duty period limitations and rest time requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... time, using Coordinated Universal Time or local time, that begins at midnight and ends 24 hours later... calculated using either Coordinated Universal Time or local time to reflect the total elapsed time. Flight... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Duty period limitations and rest...

  18. 14 CFR 135.273 - Duty period limitations and rest time requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... time, using Coordinated Universal Time or local time, that begins at midnight and ends 24 hours later... calculated using either Coordinated Universal Time or local time to reflect the total elapsed time. Flight... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Duty period limitations and rest...

  19. Structure and dating errors in the geologic time scale and periodicity in mass extinctions

    NASA Technical Reports Server (NTRS)

    Stothers, Richard B.

    1989-01-01

    Structure in the geologic time scale reflects a partly paleontological origin. As a result, ages of Cenozoic and Mesozoic stage boundaries exhibit a weak 28-Myr periodicity that is similar to the strong 26-Myr periodicity detected in mass extinctions of marine life by Raup and Sepkoski. Radiometric dating errors in the geologic time scale, to which the mass extinctions are stratigraphically tied, do not necessarily lessen the likelihood of a significant periodicity in mass extinctions, but do spread the acceptable values of the period over the range 25-27 Myr for the Harland et al. time scale or 25-30 Myr for the DNAG time scale. If the Odin time scale is adopted, acceptable periods fall between 24 and 33 Myr, but are not robust against dating errors. Some indirect evidence from independently-dated flood-basalt volcanic horizons tends to favor the Odin time scale.

  20. Future Economics of Liver Transplantation: A 20-Year Cost Modeling Forecast and the Prospect of Bioengineering Autologous Liver Grafts

    PubMed Central

    Habka, Dany; Mann, David; Landes, Ronald; Soto-Gutierrez, Alejandro

    2015-01-01

    During the past 20 years liver transplantation has become the definitive treatment for most severe types of liver failure and hepatocellular carcinoma, in both children and adults. In the U.S., roughly 16,000 individuals are on the liver transplant waiting list. Only 38% of them will receive a transplant due to the organ shortage. This paper explores another option: bioengineering an autologous liver graft. We developed a 20-year model projecting future demand for liver transplants, along with costs based on current technology. We compared these cost projections against projected costs to bioengineer autologous liver grafts. The model was divided into: 1) the epidemiology model forecasting the number of wait-listed patients, operated patients and postoperative patients; and 2) the treatment model forecasting costs (pre-transplant-related costs; transplant (admission)-related costs; and 10-year post-transplant-related costs) during the simulation period. The patient population was categorized using the Model for End-Stage Liver Disease score. The number of patients on the waiting list was projected to increase 23% over 20 years while the weighted average treatment costs in the pre-liver transplantation phase were forecast to increase 83% in Year 20. Projected demand for livers will increase 10% in 10 years and 23% in 20 years. Total costs of liver transplantation are forecast to increase 33% in 10 years and 81% in 20 years. By comparison, the projected cost to bioengineer autologous liver grafts is $9.7M based on current catalog prices for iPS-derived liver cells. The model projects a persistent increase in need and cost of donor livers over the next 20 years that’s constrained by a limited supply of donor livers. The number of patients who die while on the waiting list will reflect this ever-growing disparity. Currently, bioengineering autologous liver grafts is cost prohibitive. However, costs will decline rapidly with the introduction of new manufacturing

  1. 21 CFR 60.28 - Time frame for determining regulatory review periods.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Time frame for determining regulatory review periods. 60.28 Section 60.28 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PATENT TERM RESTORATION Regulatory Review Period Determinations § 60.28 Time frame...

  2. 33 CFR 164.55 - Deviations from rules: Continuing operation or period of time.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Deviations from rules: Continuing operation or period of time. The Captain of the Port, upon written... in the waters under the jurisdiction of the Captain of the Port for any continuing operation or period of time the Captain of the Port specifies....

  3. 21 CFR 60.28 - Time frame for determining regulatory review periods.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Time frame for determining regulatory review periods. 60.28 Section 60.28 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PATENT TERM RESTORATION Regulatory Review Period Determinations § 60.28 Time frame...

  4. 47 CFR 54.724 - Time periods for Commission approval of Administrator decisions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 3 2014-10-01 2014-10-01 false Time periods for Commission approval of...) COMMON CARRIER SERVICES (CONTINUED) UNIVERSAL SERVICE Review of Decisions Issued by the Administrator § 54.724 Time periods for Commission approval of Administrator decisions. (a) The Wireline...

  5. 47 CFR 54.724 - Time periods for Commission approval of Administrator decisions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 3 2013-10-01 2013-10-01 false Time periods for Commission approval of...) COMMON CARRIER SERVICES (CONTINUED) UNIVERSAL SERVICE Review of Decisions Issued by the Administrator § 54.724 Time periods for Commission approval of Administrator decisions. (a) The Wireline...

  6. 47 CFR 54.724 - Time periods for Commission approval of Administrator decisions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 3 2012-10-01 2012-10-01 false Time periods for Commission approval of...) COMMON CARRIER SERVICES (CONTINUED) UNIVERSAL SERVICE Review of Decisions Issued by the Administrator § 54.724 Time periods for Commission approval of Administrator decisions. (a) The Wireline...

  7. 47 CFR 54.724 - Time periods for Commission approval of Administrator decisions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 3 2011-10-01 2011-10-01 false Time periods for Commission approval of...) COMMON CARRIER SERVICES (CONTINUED) UNIVERSAL SERVICE Review of Decisions Issued by the Administrator § 54.724 Time periods for Commission approval of Administrator decisions. (a) The Wireline...

  8. 47 CFR 54.724 - Time periods for Commission approval of Administrator decisions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Time periods for Commission approval of...) COMMON CARRIER SERVICES (CONTINUED) UNIVERSAL SERVICE Review of Decisions Issued by the Administrator § 54.724 Time periods for Commission approval of Administrator decisions. (a) The Wireline...

  9. 12 CFR 516.10 - How does OTS compute time periods under this part?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 5 2010-01-01 2010-01-01 false How does OTS compute time periods under this part? 516.10 Section 516.10 Banks and Banking OFFICE OF THRIFT SUPERVISION, DEPARTMENT OF THE TREASURY APPLICATION PROCESSING PROCEDURES § 516.10 How does OTS compute time periods under this part? In...

  10. Optimising treatment strategies in spinal ependymoma based on 20years of experience at a single centre.

    PubMed

    Keil, Vera C; Schmitt, Anne J; Martin, Sean C; Cadoux-Hudson, Tom A D; Pereira, Erlick A C

    2016-07-01

    Spinal ependymomas are rare tumours, with total resection favoured where possible. Several case series assessing the outcome following neurosurgical treatment for spinal ependymoma advocate the usage of adjuvant radiotherapy in cases of subtotal resection, or in unencapsulated tumours. We assessed the outcome of 61 consecutive cases of spinal ependymoma in a single centre over a 20year period using a variety of outcome measures. Sex distribution was equal, with a mean age at surgery of 43.6years (range 5-76years). Overall, most tumours occurred in the lumbosacral region (70.5%), with fewer in the thoracic (27.9%) and cervical regions (18.0%). Myxopapillary features were seen in 41.0% of tumours, and were more common when occurring in the lumbar region (51.2%). Gross total resection was achieved in 52.5%, subtotal resection in 37.7% and biopsy alone in 9.8% of patients and 31.1% received adjuvant radiotherapy. Two-thirds of patients achieved an excellent post-operative neurological outcome (Frankel grade E). Tumour recurrence was rare. Gross total resection and good preoperative neurological condition were most strongly predictive of good outcome. Post-operative radiotherapy did not seem to confer survival benefit in this case series, even in cases of incomplete resection, leading us to question its utility for all cases of spinal cord ependymoma.

  11. Trends in acoustic neuroma management: a 20-year review of the oxford skull base clinic.

    PubMed

    Mackeith, Samuel A C; Kerr, Richard S; Milford, Chris A

    2013-08-01

    Objective To describe the change in the management of acoustic neuromas at one United Kingdom center over a 20-year period and to compare this with what is known regarding trends in practice on a national and international scale. Design, Setting, and Participants Data was collected prospectively on all patients attending the Oxford Skull Base Clinic between 1990 and 2009. Main Outcome Measures The proportion of patients managed initially by observation versus radiotherapy versus surgery was recorded for each year. Results Significantly more patients received radiation treatment (instead of surgery) between 2000 and 2009 when compared with 1990 to 1999. Compared with national audit data, the Oxford Skull Base Clinic treats a higher proportion of patients with radiotherapy and significantly lower proportion with surgery, though the trend nationally is toward more observation and radiotherapy and less surgery. Conclusion Surgery will remain crucial in the management of some patients with acoustic neuromas (usually those with the larger tumors where radiosurgery is recognized to be less appropriate), but using current trends to predict future practice would suggest that alternative nonmicrosurgical treatment may play an increasingly important role in the future.

  12. Suicide and Fire: A 20-Year Study of Self-Immolation Death in Sousse, Tunisia.

    PubMed

    Jedidi, Maher; Cherif El Khal, Mohamed; Mlayeh, Souheil; Masmoudi, Tasnim; Mahjoub, Mohamed; Yassine Brahem, Mohamed; Ben Dhiab, Mohamed; Zemni, Majed; Kamel Souguir, Mohamed

    2016-11-15

    Self-immolation is a self-destructive conduct described since antiquity. Its frequency is variable from one country to another and it is a real public health problem in parts of the world. In Tunisia, after the 2011 revolution the problem of self-immolation protest has been highly publicized giving the impression of an increase in this phenomenon. This is a retrospective analysis of all fatal self-immolation cases, collected over a 20-year period (1996-2015) at the Forensic Medicine Department of the Farhat Hached University Hospital, Sousse, Tunisia. A total of 41 cases were collected, of which 23 were men (56%). The mean age was 36.1 years. Prior to 2011, 78.9% of the victims of self-immolation were women and after 2011, 86.4% were men. The rural origin of the victims was found in 56.25% of the cases. History of psychiatric illness was found in four individuals. The self-immolation took place in the victims' homes in 19 cases (46.3%). It came after a conjugal or family conflict in 14 cases (34.1%) and it is of protest character in 8 cases (19.5%). This study confirmed the increasing frequency of self-immolation in Tunisia after the 2011 revolution and noted a change in the victims' profiles.

  13. Developing new mathematical method for search of the time series periodicity with deletions and insertions

    NASA Astrophysics Data System (ADS)

    Korotkov, E. V.; Korotkova, M. A.

    2017-01-01

    The purpose of this study was to detect latent periodicity in the presence of deletions or insertions in the analyzed data, when the points of deletions or insertions are unknown. A mathematical method was developed to search for periodicity in the numerical series, using dynamic programming and random matrices. The developed method was applied to search for periodicity in the Euro/Dollar (Eu/) exchange rate, since 2001. The presence of periodicity within the period length equal to 24 h in the analyzed financial series was shown. Periodicity can be detected only with insertions and deletions. The results of this study show that periodicity phase shifts, depend on the observation time. The reasons for the existence of the periodicity in the financial ranks are discussed.

  14. [20 years' experience in the treatment of children with terminal renal insufficiency in Yugoslavia].

    PubMed

    Peco-Antić, A; Popović-Rolović, M; Jovanović, O; Marsenić, O; Babić, D; Kostić, M; Kruscić, O; Culić, D; Trajković, D

    2000-01-01

    The first specialized haemodialysis (HD) paediatric centre in former Yugoslavia was established at the University Children's Hospital in Belgrade in January 1980. A total of 194 children (F: 98, M: 96), aged less than 19 years (10.12 +/- 4.23), were treated for renal replacement therapy (RRT) over 20 years. Average annual incidence rate was 1.59 per million of child population (pmcp) aged less than 19 years for the period 1980-1990 (former Yugoslavia) and 2.85 pmcp aged less than 19 years for the period 1990-2000 (present Yugoslavia). Reflux nephropathy was the most frequent underlying disease and accounted for 37.06% of total cases, while other primary renal diseases were: glomerulonephritis (GN) 17.26%, cystic/hereditary familial nephropathy 12.69%, congenital disease 11.68%, interstitial nephritis 5.58%, non-recovered tubular necrosis 3.55%, secondary GN 1.52% and 10.66% remained with doubtful diagnosis. HD was the first RRT in 84.02%, peritoneal dialysis (PD) in 14.43% and pre-emptive transplantation in 1.55% of all patients. A total of 53 patients (27.3% of total terminal renal failure (TRF) patients) received 56 kidney transplants (58.93% live related, 37.50% cadaveric, 3.57% live-non related). Actual survival in RRT was 64.53% 5 in years; 51.68% in 10 and 48.23% in 15 years. Patient survival in HD was significantly better over the last ten-year period than in the first ten-year period (35.88% vs. 75.75%; p < 0.005) as well as the survival of transplanted patients in the same two periods (67.62% vs. 95.45%). Graft survival was 79.85% in 5 and 70.50% in 10 years. Cardiovascular complications were the most common cause of death of patients on RRT (56.10 posto) followed by infection (24.39). On December 31, 1999, 54 patients on RRT were alive less than 19 years: 75.92% in HD; 22.22% with functioning graft and 1.85% on automatic PD. This is the first national-wide long-term study of incidence and aetiology of paediatric TRF and outcome of paediatric RRT in

  15. Portion Distortion! Do You Know How Food Portions Have Changed in 20 Years?

    MedlinePlus

    ... eNewsletters Calendar Portion Distortion Do You Know How Food Portions Have Changed in 20 Years? Anyone eating ... run or at restaurants has probably noticed that food portions have gotten larger. Some portions are called " ...

  16. Multilevel learning in the adaptive management of waterfowl harvests: 20 years and counting

    USGS Publications Warehouse

    Johnson, Fred A.; Boomer, G. Scott; Williams, Byron K.; Nichols, James D.; Case, David J.

    2015-01-01

    In 1995, the U.S. Fish and Wildlife Service implemented an adaptive harvest management program (AHM) for the sport harvest of midcontinent mallards (Anas platyrhynchos). The program has been successful in reducing long-standing contentiousness in the regulatory process, while integrating science and policy in a coherent, rigorous, and transparent fashion. After 20 years, much has been learned about the relationship among waterfowl populations, their environment, and hunting regulations, with each increment of learning contributing to better management decisions. At the same time, however, much has been changing in the social, institutional, and environmental arenas that provide context for the AHM process. Declines in hunter numbers, competition from more pressing conservation issues, and global-change processes are increasingly challenging waterfowl managers to faithfully reflect the needs and desires of stakeholders, to account for an increasing number of institutional constraints, and to (probabilistically) predict the consequences of regulatory policy in a changing environment. We review the lessons learned from the AHM process so far, and describe emerging challenges and ways in which they may be addressed. We conclude that the practice of AHM has greatly increased an awareness of the roles of social values, trade-offs, and attitudes toward risk in regulatory decision-making. Nevertheless, going forward the waterfowl management community will need to focus not only on the relationships among habitat, harvest, and waterfowl populations, but on the ways in which society values waterfowl and how those values can change over time

  17. A 20-year study on 190 patients with primary hyperparathyroidism in a developing country: Turkey experience.

    PubMed

    Usta, Arif; Alhan, Etem; Cinel, Akif; Türkyılmaz, Serdar; Erem, Cihangir

    2015-04-01

    The aim of this study was to present our 20-year experience regarding primary hyperparathyroidism (PHPT). PHPT patients who underwent parathyroidectomy in our clinic were reviewed retrospectively. There were 190 PHPT patients, of whom 137 were asymptomatic (72%). The mean serum calcium at the time of diagnosis was 11.9 ± 2.2 mg/dL. The mean parathyroid hormone (PTH) level was 467 ± 78 pg/mL. Ultrasonography (USG) identified all abnormal glands accurately (82.6%) and Technetium-99m sestamibi scintigraphy (MIBI) was used in 89.4% of the patients and magnetic resonance imaging (MRI) in 61%. The common use of USG and MIBI detected 92% of the lesions. Bilateral neck exploration (BNE) was performed in 12.2% of the patients and focused unilateral neck exploration (FUNE) in the remaining 87.8%. Surgical intervention was unsuccessful in 1 patient (0.5%). The conversion ratio from FUNE to BNE was 5.2%. The mean operation time and mean hospital stay decreased significantly in patients with FUNE. Pathologic examination revealed single adenoma in 93% of the patients. New imaging techniques result in the conversion of surgical treatments of PHPT. FUNE in parathyroidectomy performed by an experienced surgeon may provide successful treatment rates.

  18. Identification of periods of clear sky irradiance in time series of GHI measurements

    SciTech Connect

    Reno, Matthew J.; Hansen, Clifford W.

    2016-01-18

    In this study, we present a simple algorithm for identifying periods of time with broadband global horizontal irradiance (GHI) similar to that occurring during clear sky conditions from a time series of GHI measurements. Other available methods to identify these periods do so by identifying periods with clear sky conditions using additional measurements, such as direct or diffuse irradiance. Our algorithm compares characteristics of the time series of measured GHI with the output of a clear sky model without requiring additional measurements. We validate our algorithm using data from several locations by comparing our results with those obtained from a clear sky detection algorithm, and with satellite and ground-based sky imagery.

  19. An efficient tracer experimental design for measuring time-variable transit time distributions in periodic hydrodynamic systems

    NASA Astrophysics Data System (ADS)

    Harman, Ciaran; Kim, Minseok

    2014-05-01

    The time-varying transport dynamics of complex hydrodynamic systems with long transit times are difficult to observe even in experimental systems due to the need for multiple tracer injections. Where only one or two distinct tracers are available, overprinting in the output concentrations limits the injection frequency. We will present an experimental method (the PERiodic Tracer Hierarchy - PERTH) that allows overprinted breakthrough curves to be decomposed into contributions from multiple injections of the same tracer, so long as the transporting flow is periodic. This method allows the time varying transit time distributions to be observed efficiently while making no a priori assumptions about the transport processes operating in the system. Simulations of transport through a soil column subject to a periodic sequence of irrigation events demonstrate that the distinct transit time distributions associated with each irrigation event can be retrieved almost exactly.

  20. Time-periodic and stationary solutions to the compressible Hall-magnetohydrodynamic system

    NASA Astrophysics Data System (ADS)

    Cheng, Ming

    2017-04-01

    We are concerned with the 3-D compressible Hall-magnetohydrodynamic system with a time-periodic external force in a periodic domain, and establish the existence of a strong time-periodic solution under some smallness and symmetry assumptions by adapting a new approach. The basic idea of the proof is the following. First, we prove the existence of a time-periodic solution to the linearized system by applying the Tychonoff fixed point theorem combined with the energy method and the decay estimates. From the details of the proof, we see that the initial data of the time-periodic solution to the linearized system lies in some convex hull. Then, we construct a set-value function, such that the fixed point of this function is a time-periodic solution of the compressible Hall-magnetohydrodynamic system. The existence of the fixed point is obtained by the Kakutani fixed point theorem. Moreover, we establish the uniqueness of the time-periodic solution and the existence of the stationary solution.

  1. Progression of HIV infection and mortality by hepatitis C infection in patients with haemophilia over 20 years.

    PubMed

    Quintana, M; del Amo, J; Barrasa, A; Pérez-Hoyos, S; Ferreros, I; Hernández, F; Villar, A; Jiménez, V; Bolúmar, F

    2003-09-01

    Hepatitis C virus (HCV) infection is an important cause of mortality in human immune deficiency virus (HIV)-positive haemophiliacs. This study describes progression to AIDS, death from HCV end-stage liver disease (ESLD) and all-cause mortality over 20 years. All HIV-positive haemophiliacs in La Paz University Hospital were included in this cohort. HIV seroconversion was estimated using mathematical techniques for interval-censored data from 1979 to 1985. Poisson regression was used to estimate rates of AIDS, death from ESLD and all causes in different periods: before 1988, 1988-89, 1990-91, 1992-93, 1994-95, 1996-97 and 1998-2001 using competing risk models. Among 383 cohort members, global AIDS incidence was 9.7 per 100 person-years, peaking in 1992-93 and dropping by 87% in 1998-2001 compared with before 1988 [incidence rate ratio (IRR) 0.13; 95% CI: 0.03-0.53]. Overall mortality was 7.5 per 100 person-years, was highest from 1992 to 1997, and fell by 66% in 1998-2001 compared with before 1988 (IRR 0.34; 95% CI: 0.14-0.81). Eighteen (5%) persons died of ESLD which represented 19% of deaths before 1988, 4% during 1988-89, 1990-91 and 1992-93, 2% in 1994-95, 10% in 1996-97 and 33% in 1998-2001. Overall death rate from ESLD was 0.5 cases per 100 person-years with no statistically significant trend observed over time. Important reductions in HIV disease progression to AIDS and death have been observed from 1998 to 2001, and can be attributed to highly active antiretroviral therapy. Although no increase in the rate of HCV-related deaths can be demonstrated, HCV accounts for an increasing proportion of deaths in the recent years.

  2. 20 Years of Developing Capacity for Action-Oriented Collaborative Regional Research in the Asia-Pacific Region

    NASA Astrophysics Data System (ADS)

    Tupas, L. M.; Stevenson, L. A.

    2015-12-01

    During its 3rd strategic phase, which ran from 2010 to 2015, the APN provided support for 123 projects through its competitive collaborative regional research and capacity development programmes. With over 250 peer-reviewed papers and the underlying philosophy that the regional research it undertakes engages at least two developing countries, the 3rd strategic phase is not only improving the research capabilities of nations in the region, but is engaging the developing country community in underpinning policy-relevant research. The extent to which science is contributing to policy is further evident in that 69% of the activities conducted had some form of science-policy mechanism built in to the project activities. The period of the 3rd Strategic Phase has been witness to significant changes in the make-up of the "conventional" global change arena, with the transition of some global change programmes into the new "Future Earth" initiative. At the same time, major events such as the Rio+20 Summit, the post-2015 Sustainable Development Goals, the establishment of an IPCC-related platform for biodiversity, i.e. IPBES, and the evolving engagement of science and policy communities has kept the APN busy at what it does best - networking and partnering with the international community. The APN has embraced these changes through its dynamism, allowing the APN to meet not only the needs of the scientists and decision makers its serves in the region but those of the international science communities as well. The challenge for the APN in its next two decades will be to ensure alignment with the transforming global change arena. With key phrases such as "policy-relevant science" and "science-policy interactions" being adopted broadly by the community at large these days, the APN's niche in the global community has received considerable recognition, particularly as other institutions strive to adopt similar practices that the APN has built over the last 20 years.

  3. Existence of time-periodic weak solutions to the stochastic Navier-Stokes equations around a moving body

    SciTech Connect

    Chen, Feng E-mail: hanyc@jlu.edu.cn; Han, Yuecai E-mail: hanyc@jlu.edu.cn

    2013-12-15

    The existence of time-periodic stochastic motions of an incompressible fluid is obtained. Here the fluid is subject to a time-periodic body force and an additional time-periodic stochastic force that is produced by a rigid body moves periodically stochastically with the same period in the fluid.

  4. 40 CFR 93.162 - Emissions beyond the time period covered by the SIP.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... covered by the SIP. 93.162 Section 93.162 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 93.162 Emissions beyond the time period covered by the SIP. If a Federal action would result in total... period covered by the SIP, the Federal agency can: (a) Demonstrate conformity with the last...

  5. 40 CFR 93.162 - Emissions beyond the time period covered by the SIP.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... covered by the SIP. 93.162 Section 93.162 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 93.162 Emissions beyond the time period covered by the SIP. If a Federal action would result in total... period covered by the SIP, the Federal agency can: (a) Demonstrate conformity with the last...

  6. 40 CFR 93.162 - Emissions beyond the time period covered by the SIP.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... covered by the SIP. 93.162 Section 93.162 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 93.162 Emissions beyond the time period covered by the SIP. If a Federal action would result in total... period covered by the SIP, the Federal agency can: (a) Demonstrate conformity with the last...

  7. 40 CFR 93.162 - Emissions beyond the time period covered by the SIP.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... covered by the SIP. 93.162 Section 93.162 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... § 93.162 Emissions beyond the time period covered by the SIP. If a Federal action would result in total... period covered by the SIP, the Federal agency can: (a) Demonstrate conformity with the last...

  8. Fast converging exact power series for the time and period of the simple pendulum

    NASA Astrophysics Data System (ADS)

    Benacka, Jan

    2017-03-01

    A time explicit fast converging exact power series solution to the pendulum equation is derived in this paper. A novel series for the period results from it. The approximate formula that comprises the first three terms gives an accuracy of 99.99% up to the amplitude of 90°. The accuracy was compared with that of 11 other approximate period formulas.

  9. Implant survival and radiographic outcome of total hip replacement in patients less than 20 years old

    PubMed Central

    Tsukanaka, Masako; Halvorsen, Vera; Nordsletten, Lars; EngesæTer, Ingvild Ø; EngesæTer, Lars B; Marie Fenstad, Anne; Röhrl, Stephan M

    2016-01-01

    Background and purpose Total hip replacement (THR) is not recommended for children and very young teenagers because early and repetitive revisions are likely. We investigated the clinical and radiographic outcomes of THR performed in children and teenage patients. Patients and methods We included 111 patients (132 hips) who underwent THR before 20 years of age. They were identified in the Norwegian Arthroplasty Register, together with information on the primary diagnosis, types of implants, and any revisions that required implant change. Radiographs and Harris hip score (HHS) were also evaluated. Results The mean age at primary THR was 17 (11–19) years and the mean follow-up time was 14 (3–26) years. The 10-year survival rate after primary THR (with the endpoint being any revision) was 70%. 39 patients had at least 1 revision and 16 patients had 2 or more revisions. In the latest radiographs, osteolysis and atrophy were observed in 19% and 27% of the acetabulae and 21% and 62% of the femurs, respectively. The mean HHS at the final follow-up was 83 (15–100). Interpretation The clinical score after THR in these young patients was acceptable, but many revisions had been performed. However, young patients with developmental dysplasia of the hip had lower implant survival. Moreover, the bone stock in these patients was poor, which could complicate future revisions. PMID:27435903

  10. 20 Years On: Is It Time to Redefine the Systemic Inflammatory Response to Cardiothoracic Surgery?

    PubMed

    Landis, R Clive

    2015-03-01

    The "systemic inflammatory response" has never been defined from a cardiothoracic surgery perspective, but borrowed its definition from the critical care field at a landmark 1992 definition conference on sepsis. It is unclear why the diagnostic criteria for the Systemic Inflammatory Response Syndrome (SIRS) were adopted in isolation, ignoring other potentially more useful definitions for Severe Septic Shock or Secondary Multiple Organ Dysfunction Syndrome. The 1992 SIRS definition for sepsis has since been updated at a conference in 2001 advocating PIRO (Predisposition, Infection, host Response, Organ dysfunction) as a hypothetical model to better link sepsis with clinical outcome. PIRO is readily adaptable to cardiothoracic surgery and provides the precedent and road map for how to update a definition. The need is obvious since the current definition of SIRS is widely disregarded in heart surgery: a dwindling proportion (14%) of articles on the systemic inflammatory response even mention SIRS and 0% monitored SIRS criteria in the past decade in an evidence-based review of anti-inflammatory interventions. The name "inflammatory response" is also problematic; it is too narrow and might be replaced with host response (the R in PIRO) to better convey the wide spectrum of host defensive pathways activated during heart surgery (i.e., complement, coagulation, fibrinolysis, kinins, cytokines, proteases, hemolysis, oxidative stiess). A variant on PIRO could allow these elements of the host Response (R) to be anchored within the context of Premorbid conditions (P) and the inevitable Insult (I) from surgery, to better link risk exposures to Organ dysfunction (O) in heart surgery. The precedent of PIRO suggests the following steps will be required to redefine the systemic inflammatory response: 1) buy-in from the leading societies for cardiothoracic surgery, anesthesia, and perfusion on the need for a re-definition conference, 2) assigning relative risk scores to different premorbid exposures, operative insults, and host response factors on clinical outcome, 3) validation of the risk model in a prospective cohort, and 4) development of algorithms or "apps" to facilitate rapid diagnosis and staging of care at bedside.

  11. Asymptotic bounds for the time-periodic solutions to the singularly perturbed ordinary differential equations.

    PubMed

    Amiraliyev, Gabil M; Ucar, Aysenur

    2013-01-01

    The periodical in time problem for singularly perturbed second order linear ordinary differential equation is considered. The boundary layer behavior of the solution and its first and second derivatives have been established. An example supporting the theoretical analysis is presented.

  12. 20 Years Experience with using Low Cost Launch Opportunities for 20 Small Satellite Missions

    NASA Astrophysics Data System (ADS)

    Meerman, Maarten; Sweeting, Martin, , Sir

    these larger 'small satellites' are too big to be carried 'piggy-back'. The entrepreneurial efforts of leading FSU rocket &missile organisations in converting existing vehicles to meet the small satellite launch market at an appropriate cost has resulted in the FSU now holding the prime position for providing launches for the small satellite community - and with an excellent track record of successful launches. However, negotiating and completing a Launch Services Agreement (LSA) for a nano-micro-minisatellite with any launcher organisation is a complex matter and risky territory for the unwary or inexperienced who may easily fall prey to unexpected additional costs and delays. Whilst this warning should be heeded when dealing with European and US organisations, it is particularly relevant when negotiating launches from the FSU where there is a plethora of agencies and organisations offering a bewildering range of launch vehicles and options. Furthermore, the FSU has developed a very different technical and managerial philosophy towards launchers when compared with the west and this can be unnerving to 'first-time buyers'. Organisations experienced in dealing in the FSU will encounter a different but excellent service - once the launch service agreement has been thoroughly and fiercely negotiated in every detail. The inexperienced, however, have encountered frustrating delays, lost opportunities, unexpected taxes and costs for additional services or facilities not originally specified, and bewilderment at the different procedures used in the FSU. Fortunately, all this can be avoided with proper experience and the FSU is the current mainstay for launching small satellites quickly, affordably and reliably. Surrey has unique experience gathered over 20 years in handling launches for 20 small satellites, ranging from a 6kg nanosatellite, 50-100kg microsatellites, and a 325kg minisatellite, using 7 different launchers from the USA, Russia, Ukraine, and Europe. By working

  13. When folic acid fails: Insights from 20 years of neural tube defect surveillance in South Carolina.

    PubMed

    Bupp, Caleb P; Sarasua, Sara M; Dean, Jane H; Stevenson, Roger E

    2015-10-01

    Neural tube defects (NTDs) are the most common of the severe malformations of the brain and spinal cord. Increased maternal intake of folic acid (FA) during the periconceptional period is known to reduce NTD risk. Data from 1046 NTD cases in South Carolina were gathered over 20 years of surveillance. It was possible to determine maternal periconceptional FA use in 615 NTD-affected pregnancies. In 163 occurrent (26.9%) and two recurrent (22%) NTD cases, the mothers reported periconceptional FA use. These women were older and more likely to be white. Maternal periconceptional FA usage was reported in 40.4% of cases of spina bifida with other anomalies but in only 25.2% of isolated spina bifida cases (P = 0.02). This enrichment for associated anomalies was not noted among cases of anencephaly or of encephalocele. Among the 563 subsequent pregnancies to mothers with previous NTD-affected pregnancies, those taking FA had a 0.4% NTD recurrence rate, but the recurrence without FA was 8.5%. NTDs with other associated findings were less likely to be prevented by FA, suggesting there is a background NTD rate that cannot be further reduced by FA. Nonetheless, the majority (73.9%) of NTDs in pregnancies in which the mothers reported periconceptional FA use were isolated NTDs of usual types. Cases in which FA failed in prevention of NTDs provide potential areas for further study into the causation of NTDs. The measures and techniques implemented in South Carolina can serve as an effective and successful model for prevention of NTD occurrence and recurrence.

  14. Water balance along a chain of tundra lakes: A 20-year isotopic perspective

    NASA Astrophysics Data System (ADS)

    Gibson, J. J.; Reid, R.

    2014-11-01

    Stable isotope measurements and isotope mass balance (IMB) calculations are presented in support of an unprecedented 20-year water balance assessment for a tailings pond and a chain of downstream lakes at the Salmita-Tundra mine site, situated near Courageous Lake, Northwest Territories, Canada (65°03‧N; 111°11‧W). The method is shown to provide a comprehensive annual and interannual perspective of water balance fluxes along a chain of lakes during the period 1991-2010, without the need for continuous streamflow gauging, and reveals important lake-order-dependent patterns of land-surface runoff, discharge accumulation, and several key diagnostic ratios, i.e., evaporation/inflow, evaporation/evapotranspiration, land-surface-runoff/precipitation and discharge/ precipitation. Lake evaporation is found to be a significant component of the water balance, accounting for between 26% and 32% of inflow to natural lakes and between 72% and 100% of inflow to mine-tailings ponds. Evaporation/evapotranspiration averages between 7% and 22% and is found to be higher in low-precipitation years, and in watersheds with a higher proportion of lakes. Runoff ratios for land-surface drainages and runoff ratios for watersheds (including lakes) ranged between 14-47% and 20-47%, respectively, and were higher in low precipitation years, in watersheds with a higher proportion of lakes, and in watersheds less affected by mining development. We propose that in general these two runoff ratios will likely converge as lake order increases and as land cover conditions become regionally representative. Notably, the study demonstrates application of IMB, validated with streamflow measurements, to constrain local water balance in a remote low-arctic region. For IMB chain-of-lakes applications, it underlines the importance of accounting for evaporatively-enriched upstream sources to avoid overestimation of evaporation losses.

  15. Cytochrome P4501A biomarker indication of oil exposure in harlequin ducks up to 20 years after the Exxon Valdez oil spill

    USGS Publications Warehouse

    Esler, Daniel; Trust, Kimberly A.; Ballachey, Brenda E.; Iverson, Samuel A.; Lewis, Tyler L.; Rizzolo, Daniel; Mulcahy, Daniel M.; Miles, A. Keith; Woodin, Bruce R.; Stegeman, John J.; Henderson, John D.; Wilson, Barry W.

    2010-01-01

    Hydrocarbon-inducible cytochrome P4501A (CYP1A) expression was measured, as ethoxyresorufin-O-deethylase (EROD) activity, in livers of wintering harlequin ducks (Histrionicus histrionicus) captured in areas of Prince William Sound, Alaska, USA, oiled by the 1989 Exxon Valdez spill and in birds from nearby unoiled areas, during 2005 to 2009 (up to 20 years following the spill). The present work repeated studies conducted in 1998 that demonstrated that in harlequin ducks using areas that received Exxon Valdez oil, EROD activity was elevated nearly a decade after the spill. The present findings strongly supported the conclusion that average levels of hepatic EROD activity were higher in ducks from oiled areas than those from unoiled areas during 2005 to 2009. This result was consistent across four sampling periods; furthermore, results generated from two independent laboratories using paired liver samples from one of the sampling periods were similar. The EROD activity did not vary in relation to age, sex, or body mass of individuals, nor did it vary strongly by season in birds collected early and late in the winter of 2006 to 2007, indicating that these factors did not confound inferences about observed differences between oiled and unoiled areas. We interpret these results to indicate that harlequin ducks continued to be exposed to residual Exxon Valdez oil up to 20 years after the original spill. This adds to a growing body of literature suggesting that oil spills have the potential to affect wildlife for much longer time frames than previously assumed.

  16. An infinite branching hierarchy of time-periodic solutions of the Benjamin-Ono equation

    SciTech Connect

    Wilkening, Jon

    2008-07-01

    We present a new representation of solutions of the Benjamin-Ono equation that are periodic in space and time. Up to an additive constant and a Galilean transformation, each of these solutions is a previously known, multi-periodic solution; however, the new representation unifies the subset of such solutions with a fixed spatial period and a continuously varying temporal period into a single network of smooth manifolds connected together by an infinite hierarchy of bifurcations. Our representation explicitly describes the evolution of the Fourier modes of the solution as well as the particle trajectories in a meromorphic representation of these solutions; therefore, we have also solved the problem of finding periodic solutions of the ordinary differential equation governing these particles, including a description of a bifurcation mechanism for adding or removing particles without destroying periodicity. We illustrate the types of bifurcation that occur with several examples, including degenerate bifurcations not predicted by linearization about traveling waves.

  17. The Pu'u 'O'o-Kupaianaha Eruption of Kilauea Volcano, Hawaii: The First 20 Years

    USGS Publications Warehouse

    Heliker, Christina C.; Swanson, Donald A.; Takahashi, Taeko Jane

    2003-01-01

    The Pu'u 'O'o-Kupaianaha eruption started on January 3, 1983. The ensuing 20-year period of nearly continuous eruption is the longest at Kilauea Volcano since the famous lava-lake activity of the 19th century. No rift-zone eruption in more than 600 years even comes close to matching the duration and volume of activity of these past two decades. Fortunately, such a landmark event came during a period of remarkable technological advancements in volcano monitoring. When the eruption began, the Global Positioning System (GPS) and the Geographic Information System (GIS) were but glimmers on the horizon, broadband seismology was in its infancy, and the correlation spectrometer (COSPEC), used to measure SO2 flux, was still very young. Now, all of these techniques are employed on a daily basis to track the ongoing eruption and construct models about its behavior. The 12 chapters in this volume, written by present or past Hawaiian Volcano Observatory staff members and close collaborators, celebrate the growth of understanding that has resulted from research during the past 20 years of Kilauea's eruption. The chapters range widely in emphasis, subject matter, and scope, but all present new concepts or important modifications of previous ideas - in some cases, ideas long held and cherished.

  18. Characterization of Discrete-Time Linear Periodically Time-Varying Systems

    DTIC Science & Technology

    1991-07-26

    transmission function (see Zadeh, 1961, Zadeh and Desoer , 1963, D’Angelo, 1970, Claasen and Mecklenbrauker, 1982, and Crochiere and Rabiner, 1983). Chapter...Zadeh, 1961, Zadeh and Desoer , 1963, D’Angelo, 1970, Claasen and Mecklenbrauker, 1982, arid Crochiere and Rabiner, 1983). Characterizations of such...LTV systems. For a more thorough treatment of the subject, see D’Angelo, 1970, Crochiere and Rabiner, 1983, and Zadeh and Desoer , 1963. 2.1 TIME-DOMAIN

  19. High Overweight and Obesity in Fontan Patients: A 20-Year History.

    PubMed

    Chung, Stephanie T; Hong, Borah; Patterson, Lance; Petit, Christopher J; Ham, J Nina

    2016-01-01

    The prevalence of obesity in long-term survivors with complex congenital heart disease may be increasing, and little is known about the timing and onset of weight gain and growth patterns in these high-risk patients. Prevalence rates of overweight/obesity and longitudinal changes in body mass index (BMI) with age were determined in 606 patients with Fontan circulation seen at a tertiary care cardiology center from 1992 to 2012. The number of clinic encounters (n) was stratified by age group (n = 401, 2-5 years; n = 333, 6-11 years; n = 217, 12-19 years; and n = 129, >20 years). Among adults, 39% were overweight/obese at last clinic visit; 22% overweight, and 17% obese. Childhood anthropometric data were available for 82 adults, of which 15% (n = 12/82) were overweight/obese in childhood. The likelihood of being overweight/obese as an adult was three times higher if there was a BMI ≥ 85th percentile in childhood (CI 2.1-4.5, P < 0.01). Overweight/obesity in adulthood was associated with lower heart failure rates (4 vs. 19%, P = 0.03). Pediatric rates of overweight/obesity were comparable to national data (NHANES 2011-2012) in every age group: at 2-5 years, (25 vs. 23%), 6-11 years (26 vs. 34%), and 12-19 years (15 vs. 35%). Systolic blood pressure was higher in overweight/obese children as young as 2-5 years of age. Childhood and adult survivors with Fontan circulation have high rates of overweight/obesity. Childhood obesity is a strong predictor of future adiposity and is linked to changes in systolic blood pressure at a very young age.

  20. Food price and diet and health outcomes: 20 years of The CARDIA Study

    PubMed Central

    Duffey, Kiyah J.; Gordon-Larsen, Penny; Shikany, James M.; Guilkey, David; Jacobs, David R; Popkin, Barry M.

    2010-01-01

    Background Despite surging interest in taxation as a policy to address poor food choice, US research directly examining the association of food prices with individual intake is scarce. Methods This 20-year longitudinal study included 12,123 respondent days from 5,115 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) Study. Associations between food price, dietary intake, overall energy intake, weight, and HOMA insulin resistance (HOMA-IR) scores were assessed using conditional log-log and linear regression models. Results The real price (inflated to 2006 dollars) of soda and pizza decreased over time; the price of whole milk increased. A 10% increase in the price of soda or pizza was associated with a -7.12% (95% confidence interval [CI]: -63.5, -10.71) or -11.5% (95%CI: -17.50, -5.50) change in energy from these foods respectively. A $1.00 increase in soda price was also associated with lower daily energy intake (-124 [95%CI: -198, -50] kcal), lower weight (-2.34 [95%CI: -4.00, -0.68] lbs), and lower HOMA-IR score (0.42 [95%CI: -0.60, -0.23]); similar trends were observed for pizza. A $1.00 increase in the price of both soda and pizza was associated with greater changes in total energy intake (-181.49 [95%CI: -247.79, -115.18] kcal), body weight (-3.66 [95%CI: -5.19, -2.14] lbs), and HOMA-IR (-0.45 [95%CI: -0.59, -0.31]). Conclusions Policies aimed at altering the price of soda or away-from-home pizza may be effective mechanisms to steer US adults toward a more healthful diet and help reduce long-term weight gain or insulin levels over time. PMID:20212177

  1. A levels and intelligence as predictors of medical careers in UK doctors: 20 year prospective study

    PubMed Central

    McManus, I C; Smithers, Eleni; Partridge, Philippa; Keeling, A; Fleming, Peter R

    2003-01-01

    Objective To assess whether A level grades (achievement) and intelligence (ability) predict doctors' careers. Design Prospective cohort study with follow up after 20 years by postal questionnaire. Setting A UK medical school in London. Participants 511 doctors who had entered Westminster Medical School as clinical students between 1975 and 1982 were followed up in January 2002. Main outcome measures Time taken to reach different career grades in hospital or general practice, postgraduate qualifications obtained (membership/fellowships, diplomas, higher academic degrees), number of research publications, and measures of stress and burnout related to A level grades and intelligence (result of AH5 intelligence test) at entry to clinical school. General health questionnaire, Maslach burnout inventory, and questionnaire on satisfaction with career at follow up. Results 47 (9%) doctors were no longer on the Medical Register. They had lower A level grades than those who were still on the register (P < 0.001). A levels also predicted performance in undergraduate training, performance in postregistration house officer posts, and time to achieve membership qualifications (Cox regression, P < 0.001; b=0.376, SE=0.098, exp(b)=1.457). Intelligence did not independently predict dropping off the register, career outcome, or other measures. A levels did not predict diploma or higher academic qualifications, research publications, or stress or burnout. Diplomas, higher academic degrees, and research publications did, however, significantly correlate with personality measures. Conclusions Results of achievement tests, in this case A level grades, which are particularly used for selection of students in the United Kingdom, have long term predictive validity for undergraduate and postgraduate careers. In contrast, a test of ability or aptitude (AH5) was of little predictive validity for subsequent medical careers. PMID:12869457

  2. The national marrow donor program 20 years of unrelated donor hematopoietic cell transplantation.

    PubMed

    Ballen, Karen K; King, Roberta J; Chitphakdithai, Pintip; Bolan, Charles D; Agura, Edward; Hartzman, Robert J; Kernan, Nancy A

    2008-09-01

    In the 20 years since the National Marrow Donor Program (NMDP) facilitated the first unrelated donor transplant, the organization has grown to include almost 7 million donors, and has facilitated over 30,000 transplants on 6 continents. This remarkable accomplishment has been facilitated by the efforts of over 600 employees, and an extensive international network including 171 transplant centers, 73 donor centers, 24 cord blood banks, 97 bone marrow collection centers, 91 apheresis centers, 26 HLA typing laboratories, and 26 Cooperative Registries. In this article, we review the history of the NMDP, and cite the major trends in patient demographics, graft sources, and conditioning regimens over the last 20 years.

  3. Robust control of multi-input periodic discrete-time systems with saturating actuators

    NASA Astrophysics Data System (ADS)

    Corradini, M. L.; Cristofaro, A.; Orlando, G.; Pettinari, S.

    2013-07-01

    This paper proposes the use of a time-varying sliding surface for robust transient shaping of periodic linear discrete-time plants subject to saturating actuators, in the presence of bounded matched uncertainties. A constructive procedure is presented, and ultimate boundedness of state trajectories is proved.

  4. Pseudo PT-symmetry in time periodic non-Hermitian Hamiltonians systems

    NASA Astrophysics Data System (ADS)

    Maamache, Mustapha; Lamri, Sarra; Cherbal, Omar

    2017-03-01

    We investigate the concept of the pseudo-parity-time (pseudo- PT) symmetry in periodic quantum systems. This pseudo parity-time symmetry manifests itself dynamically in the framework of the non-unitary evolution (Floquet) operator U(τ) =e-iLτ, over a period τ, which shows that the stability of the dynamics occurs when the PT-symmetry (or pseudo- PT) of the time-independent non-Hermitian Hamiltonian L is unbroken i.e. its quasienergies En are real. Nevertheless, when the PT-symmetry of the non-Hermitian Hamiltonian L is broken, which corresponds to the complex conjugate quasienergies En, an instable dynamics arises. We investigate in greater detail a harmonic oscillator with imaginary time-dependent periodic driving term linear in x. The Floquet operator for the modulated system is pseudo- PT symmetric if the relative phase ϕ of the applied mode is not 0 or π.

  5. Time period and lesbian identity events: a comparison of Norwegian lesbians across 1986 and 2005.

    PubMed

    Giertsen, Merethe; Anderssen, Norman

    2007-11-01

    The purpose of the present work was to investigate the assumption that the lives of lesbians are easier today. When exploring the hypothesis that identity events (e.g., coming out to parents) among lesbian women have changed over time and happen earlier in life today, we expected to find several time period effects. Two national samples obtained through mailed questionnaires were compared, 1986 (n = 123) and 2005 (n = 236), age range 20-49. Time period effects were found, including informants reporting identifying as lesbian earlier in life. Time period effects, however, were not found regarding relational identity events such as informing others about one's identity status. The findings did not reveal any conclusive evidence that it is easier to establish a lesbian lifestyle today.

  6. A framework for periodic outlier pattern detection in time-series sequences.

    PubMed

    Rasheed, Faraz; Alhajj, Reda

    2014-05-01

    Periodic pattern detection in time-ordered sequences is an important data mining task, which discovers in the time series all patterns that exhibit temporal regularities. Periodic pattern mining has a large number of applications in real life; it helps understanding the regular trend of the data along time, and enables the forecast and prediction of future events. An interesting related and vital problem that has not received enough attention is to discover outlier periodic patterns in a time series. Outlier patterns are defined as those which are different from the rest of the patterns; outliers are not noise. While noise does not belong to the data and it is mostly eliminated by preprocessing, outliers are actual instances in the data but have exceptional characteristics compared with the majority of the other instances. Outliers are unusual patterns that rarely occur, and, thus, have lesser support (frequency of appearance) in the data. Outlier patterns may hint toward discrepancy in the data such as fraudulent transactions, network intrusion, change in customer behavior, recession in the economy, epidemic and disease biomarkers, severe weather conditions like tornados, etc. We argue that detecting the periodicity of outlier patterns might be more important in many sequences than the periodicity of regular, more frequent patterns. In this paper, we present a robust and time efficient suffix tree-based algorithm capable of detecting the periodicity of outlier patterns in a time series by giving more significance to less frequent yet periodic patterns. Several experiments have been conducted using both real and synthetic data; all aspects of the proposed approach are compared with the existing algorithm InfoMiner; the reported results demonstrate the effectiveness and applicability of the proposed approach.

  7. Long-time Behavior of Isolated Periodically Driven Interacting Lattice Systems

    NASA Astrophysics Data System (ADS)

    D'Alessio, Luca; Rigol, Marcos

    2014-10-01

    We study the dynamics of isolated interacting spin chains that are periodically driven by sudden quenches. Using full exact diagonalization of finite chains, we show that these systems exhibit three distinct regimes. For short driving periods, the Floquet Hamiltonian is well approximated by the time-averaged Hamiltonian, while for long periods, the evolution operator exhibits properties of random matrices of a circular ensemble (CE). In between, there is a crossover regime. Based on a finite-size scaling analysis and analytic arguments, we argue that, for thermodynamically large systems and nonvanishing driving periods, the evolution operator always exhibits properties of the CE of random matrices. Consequently, the Floquet Hamiltonian is a nonlocal Hamiltonian with multispin interaction terms, and the driving leads to the equivalent of an infinite temperature state at long times. These results are connected to the breakdown of the Magnus expansion and are expected to hold beyond the specific lattice model considered.

  8. Seasonal cycle of volume transport through Kerama Gap revealed by a 20-year global HYbrid Coordinate Ocean Model reanalysis

    NASA Astrophysics Data System (ADS)

    Yu, Zhitao; Metzger, E. Joseph; Thoppil, Prasad; Hurlburt, Harley E.; Zamudio, Luis; Smedstad, Ole Martin; Na, Hanna; Nakamura, Hirohiko; Park, Jae-Hun

    2015-12-01

    The temporal variability of volume transport from the North Pacific Ocean to the East China Sea (ECS) through Kerama Gap (between Okinawa Island and Miyakojima Island - a part of Ryukyu Islands Arc) is investigated using a 20-year global HYbrid Coordinate Ocean Model (HYCOM) reanalysis with the Navy Coupled Ocean Data Assimilation from 1993 to 2012. The HYCOM mean transport is 2.1 Sv (positive into the ECS, 1 Sv = 106 m3/s) from June 2009 to June 2011, in good agreement with the observed 2.0 Sv transport during the same period. This is similar to the 20-year mean Kerama Gap transport of 1.95 ± 4.0 Sv. The 20-year monthly mean volume transport (transport seasonal cycle) is maximum in October (3.0 Sv) and minimum in November (0.5 Sv). The annual variation component (345-400 days), mesoscale eddy component (70-345 days), and Kuroshio meander component (< 70 days) are separated to determine their contributions to the transport seasonal cycle. The annual variation component has a close relation with the local wind field and increases (decreases) transport into the ECS through Kerama Gap in summer (winter). Most of the variations in the transport seasonal cycle come from the mesoscale eddy component. The impinging mesoscale eddies increase the transport into the ECS during January, February, May, and October, and decrease it in March, April, November, and December, but have little effect in summer (June-September). The Kuroshio meander components cause smaller transport variations in summer than in winter.

  9. In vitro conservation of oil palm somatic embryos for 20 years on a hormone-free culture medium: characteristics of the embryogenic cultures, derived plantlets and adult palms.

    PubMed

    Konan, K Eugene; Durand-Gasselin, Tristan; Kouadio, Y Justin; Flori, Albert; Rival, Alain; Duval, Yves; Pannetier, Catherine

    2010-01-01

    This study was conducted over a period of 20 years, to assess the problems involved in developing subcultures over a very long period, of oil palm (Elaeis guineensis Jacq.) somatic embryos which were maintained in vitro on a Murashige and Skoog mineral-based culture medium, without growth regulators. Analysis of the proliferation rate of the embryogenic cultures, along with the survivability of the regenerated plantlets after their transfer into soil and of the flowering of the derived adult palms has been conducted for cultures maintained in vitro during 1 to 20 years. From the ninth year of maintenance, the tissue quality of the somatic embryos gradually began to decline. However, after more than 20 years, 30% of the 20 clones tested still continued to proliferate satisfactorily on the same maintenance medium, keeping their multiplication potential intact. Even though a depressive effect of the age of the lines has been observed on the survival capacity of plants under natural conditions, it is noteworthy that among the clones originating from 20-year-old cultures only eight of them (40%) have exhibited the "mantled" floral abnormality. Different hypotheses concerning the origin of the disruptions observed on the in vitro cultures, plantlets and adult palms that occur over a very long period of in vitro conservation are discussed.

  10. Rank One Strange Attractors in Periodically Kicked Predator-Prey System with Time-Delay

    NASA Astrophysics Data System (ADS)

    Yang, Wenjie; Lin, Yiping; Dai, Yunxian; Zhao, Huitao

    2016-06-01

    This paper is devoted to the study of the problem of rank one strange attractor in a periodically kicked predator-prey system with time-delay. Our discussion is based on the theory of rank one maps formulated by Wang and Young. Firstly, we develop the rank one chaotic theory to delayed systems. It is shown that strange attractors occur when the delayed system undergoes a Hopf bifurcation and encounters an external periodic force. Then we use the theory to the periodically kicked predator-prey system with delay, deriving the conditions for Hopf bifurcation and rank one chaos along with the results of numerical simulations.

  11. Tracking 20 years of compound-to-target output from literature and patents.

    PubMed

    Southan, Christopher; Varkonyi, Peter; Boppana, Kiran; Jagarlapudi, Sarma A R P; Muresan, Sorel

    2013-01-01

    The statistics of drug development output and declining yield of approved medicines has been the subject of many recent reviews. However, assessing research productivity that feeds development is more difficult. Here we utilise an extensive database of structure-activity relationships extracted from papers and patents. We have used this database to analyse published compounds cumulatively linked to nearly 4000 protein target identifiers from multiple species over the last 20 years. The compound output increases up to 2005 followed by a decline that parallels a fall in pharmaceutical patenting. Counts of protein targets have plateaued but not fallen. We extended these results by exploring compounds and targets for one large pharmaceutical company. In addition, we examined collective time course data for six individual protease targets, including average molecular weight of the compounds. We also tracked the PubMed profile of these targets to detect signals related to changes in compound output. Our results show that research compound output had decreased 35% by 2012. The major causative factor is likely to be a contraction in the global research base due to mergers and acquisitions across the pharmaceutical industry. However, this does not rule out an increasing stringency of compound quality filtration and/or patenting cost control. The number of proteins mapped to compounds on a yearly basis shows less decline, indicating the cumulative published target capacity of global research is being sustained in the region of 300 proteins for large companies. The tracking of six individual targets shows uniquely detailed patterns not discernible from cumulative snapshots. These are interpretable in terms of events related to validation and de-risking of targets that produce detectable follow-on surges in patenting. Further analysis of the type we present here can provide unique insights into the process of drug discovery based on the data it actually generates.

  12. Tracking 20 Years of Compound-to-Target Output from Literature and Patents

    PubMed Central

    Southan, Christopher; Varkonyi, Peter; Boppana, Kiran; Jagarlapudi, Sarma A.R.P.; Muresan, Sorel

    2013-01-01

    The statistics of drug development output and declining yield of approved medicines has been the subject of many recent reviews. However, assessing research productivity that feeds development is more difficult. Here we utilise an extensive database of structure-activity relationships extracted from papers and patents. We have used this database to analyse published compounds cumulatively linked to nearly 4000 protein target identifiers from multiple species over the last 20 years. The compound output increases up to 2005 followed by a decline that parallels a fall in pharmaceutical patenting. Counts of protein targets have plateaued but not fallen. We extended these results by exploring compounds and targets for one large pharmaceutical company. In addition, we examined collective time course data for six individual protease targets, including average molecular weight of the compounds. We also tracked the PubMed profile of these targets to detect signals related to changes in compound output. Our results show that research compound output had decreased 35% by 2012. The major causative factor is likely to be a contraction in the global research base due to mergers and acquisitions across the pharmaceutical industry. However, this does not rule out an increasing stringency of compound quality filtration and/or patenting cost control. The number of proteins mapped to compounds on a yearly basis shows less decline, indicating the cumulative published target capacity of global research is being sustained in the region of 300 proteins for large companies. The tracking of six individual targets shows uniquely detailed patterns not discernible from cumulative snapshots. These are interpretable in terms of events related to validation and de-risking of targets that produce detectable follow-on surges in patenting. Further analysis of the type we present here can provide unique insights into the process of drug discovery based on the data it actually generates. PMID

  13. The next 20 years: how customer and workforce attitudes will evolve.

    PubMed

    Howe, Neil; Strauss, William

    2007-01-01

    Business projects with very long time horizons--such as those involving product R&D, workplace design, and total compensation planning--have to contend with a crucial question: What will be the needs, demands, and desires of consumers and employees decades from now? If you think the answer is "Just more of the same," you're in for a surprise. Howe and Strauss, the authors of Generations, The Fourth Turning, Millennials Rising, and other books, have studied the differences among generations for some 30 years. Their extensive research has revealed a fascinating pattern--one so strong that it supports a measure of predictability. On the basis of historical precedent, they say, we can foresee how the generations that are alive today will think and act in decades to come. Three of those generations will still be vital forces in American society 20 years from now: Boomers, Generation X, and Millennials. Their attitudes and behaviors will have profound effects on the economy, the workplace, and social institutions in general. For example, as aging Boomers eschew high-tech medicine in favor of holistic self-care, natural foods, and mind-body healing techniques, some hospitals are opening new wings featuring alternative medicine and spiritual counseling. Gen Xers, having grown up in an era of failing schools and marriages, will remain alienated, disaffected, and pragmatic as they enter midlife. Already the greatest entrepreneurial generation in U.S. history, they will be highly effective at pushing innovation, efficiency, and mass customization. In contrast, young adult Millennials will favor teamwork, close family relationships, job security, and a bland popular culture. Their unprecedented digital empowerment and talent for organizing will create a political powerhouse and may even revitalize the union movement.

  14. Modelling 20 years of synchrotron flaring in the jet of 3C 273

    NASA Astrophysics Data System (ADS)

    Türler, M.; Courvoisier, T. J.-L.; Paltani, S.

    2000-09-01

    We present a phenomenological jet model which is able to reproduce well the observed variations of the submillimetre-to-radio emission of the bright quasar 3C 273 during the last 20 years. It is a generalization of the original shock model of Marscher & Gear (1985), which is now able to describe an accelerating or decelerating shock wave, in a curved, non-conical and non-adiabatic jet. The model defines the properties of a synchrotron outburst which is expected to be emitted by the jet material in a small region just behind the shock front. By a proper parameterization of the average outburst's evolution and of the peculiarities of individual outbursts, we are able to decompose simultaneously thirteen long-term light-curves of 3C 273 in a series of seventeen distinct outbursts. It is the first time that a model is so closely confronted to the long-term multi-wavelength variability properties of a quasar. The ability of the model to reproduce the very different shapes of the submillimetre-to-radio light curves of 3C 273 gives strong support to the shock model of Marscher & Gear (1985). Indirectly, it also reinforces the idea that the outbursts seen in the light-curves are physically linked to the distinct features observed to move along the jet with apparently superluminal velocities. The more than 5000 submillimetre-to-radio observations in the different light-curves are able to constrain the physical properties of the jet. The results suggest, for instance, that the magnetic field behind the shock front is rather turbulent. There is also some evidence that the jet radius does not increase linearly with distance down the jet or, alternatively, that the synchrotron emitting material decelerates with distance and/or bends away from the line-of-sight.

  15. Ecosystem development after mangrove wetland creation: plant-soil change across a 20-year chronosequence

    USGS Publications Warehouse

    Osland, Michael J.; Spivak, Amanda C.; Nestlerode, Janet A.; Lessmann, Jeannine M.; Almario, Alejandro E.; Heitmuller, Paul T.; Russell, Marc J.; Krauss, Ken W.; Alvarez, Federico; Dantin, Darrin D.; Harvey, James E.; From, Andrew S.; Cormier, Nicole; Stagg, Camille L.

    2012-01-01

    Mangrove wetland restoration and creation efforts are increasingly proposed as mechanisms to compensate for mangrove wetland losses. However, ecosystem development and functional equivalence in restored and created mangrove wetlands are poorly understood. We compared a 20-year chronosequence of created tidal wetland sites in Tampa Bay, Florida (USA) to natural reference mangrove wetlands. Across the chronosequence, our sites represent the succession from salt marsh to mangrove forest communities. Our results identify important soil and plant structural differences between the created and natural reference wetland sites; however, they also depict a positive developmental trajectory for the created wetland sites that reflects tightly coupled plant-soil development. Because upland soils and/or dredge spoils were used to create the new mangrove habitats, the soils at younger created sites and at lower depths (10-30 cm) had higher bulk densities, higher sand content, lower soil organic matter (SOM), lower total carbon (TC), and lower total nitrogen (TN) than did natural reference wetland soils. However, in the upper soil layer (0-10 cm), SOM, TC, and TN increased with created wetland site age simultaneously with mangrove forest growth. The rate of created wetland soil C accumulation was comparable to literature values for natural mangrove wetlands. Notably, the time to equivalence for the upper soil layer of created mangrove wetlands appears to be faster than for many other wetland ecosystem types. Collectively, our findings characterize the rate and trajectory of above- and below-ground changes associated with ecosystem development in created mangrove wetlands; this is valuable information for environmental managers planning to sustain existing mangrove wetlands or mitigate for mangrove wetland losses.

  16. Physiological status of broiler chicks at pulling time and the relationship to duration of holding period.

    PubMed

    Tong, Q; Demmers, T; Romanini, C E B; Bergoug, H; Roulston, N; Exadaktylos, V; Bahr, C; Berckmans, D; Guinebretière, M; Eterradossi, N; Garain, P; McGonnell, I M

    2015-07-01

    Newly hatched chicks may be held longer than 48 h and experience long periods of fasting in commercial hatcheries. Limited information is known about the physiological status of chicks in such situations, due to the difficulty of precisely recording time of hatch. This study investigated the effect of the time from hatch to pulling (holding period) on physiological measures/parameters in 109 broiler chicks. Fertile Ross 308 eggs were incubated in a custom built small-scale incubator. The individual hatching time of each focal chick was determined using eggshell temperature monitoring. At 'pulling' (512 h of incubation time), the quality of focal chicks was assessed using the chick scoring method and physiological parameters were measured including BW, organ (heart, liver and stomach) weights, blood values and plasma corticosterone level. The time from hatch to pulling varied from 7.58 to 44.97 h. Egg weight at setting was significantly correlated with chick BW and weight of organs at pulling, but had no effect on chick quality, blood values and plasma corticosterone. Relative BW at pulling was negatively associated with the duration of holding period (P=0.002). However, there was a positive correlation between relative stomach weight and the duration of the holding period (P<0.001). As the holding period duration increased, there was a trend that blood partial pressure of oxygen, haematocrit and haemoglobin also increased, and blood partial pressure of carbon dioxide, total carbon dioxide and bicarbonate decreased (P<0.05). A wide range of plasma corticosterone was observed from chicks that had experienced different durations of holding period. We conclude that shortening the hatch window and minimising the number of chicks that experience a long holding period before pulling may improve chick quality and physiological status, which may be due to unfavourable environmental conditions that include feed and water deprivation.

  17. A New Framework For Helicopter Vibration Suppression; Time-Periodic System Identification and Controller Design

    NASA Astrophysics Data System (ADS)

    Ulker, Fatma Demet

    In forward flight, helicopter rotor blades function within a highly complex aerodynamic environment that includes both near-blade and far-blade aerodynamic phenomena. These aerodynamic phenomena cause fluctuating aerodynamic loads on the rotor blades. These loads when coupled with the dynamic characteristics and elastic motion of the blade create excessive amount of vibration. These vibrations degrade helicopter performance, passenger comfort and contributes to high cost maintenance problems. In an effort to suppress helicopter vibration, recent studies have developed active control strategies using active pitch links, flaps, twist actuation and higher harmonic control of the swash plate. In active helicopter vibration control, designing a controller in a computationally efficient way requires accurate reduced-order models of complex helicopter aeroelasticity. In previous studies, controllers were designed using aeroelastic models that were obtained by coupling independently reduced aerodynamic and structural dynamic models. Unfortunately, these controllers could not satisfy stability and performance criteria when implemented in high-fidelity computer simulations or real-time experiments. In this thesis, we present a novel approach that provides accurate time-periodic reduced-order models and time-periodic H2 and H infinity controllers that satisfy the stability and performance criteria. Computational efficiency and the necessity of using the approach were validated by implementing an actively controlled flap strategy. In this proposed approach, the reduced-order models were directly identified from high-fidelity coupled aeroelastic analysis by using the time-periodic subspace identification method. Time-periodic H2 and Hinfinity controllers that update the control actuation at every time step were designed. The control synthesis problem was solved using Linear Matrix Inequality and periodic Riccati Equation based formulations, for which an in-house periodic

  18. Periodic trim solutions with hp-version finite elements in time

    NASA Technical Reports Server (NTRS)

    Peters, David A.; Hou, Lin-Jun

    1990-01-01

    Finite elements in time as an alternative strategy for rotorcraft trim problems are studied. The research treats linear flap and linearized flap-lag response both for quasi-trim and trim cases. The connection between Fourier series analysis and hp-finite elements for periodic a problem is also examined. It is proved that Fourier series is a special case of space-time finite elements in which one element is used with a strong displacement formulation. Comparisons are made with respect to accuracy among Fourier analysis, displacement methods, and mixed methods over a variety parameters. The hp trade-off is studied for the periodic trim problem to provide an optimum step size and order of polynomial for a given error criteria. It is found that finite elements in time can outperform Fourier analysis for periodic problems, and for some given error criteria. The mixed method provides better results than does the displacement method.

  19. Reproductive numbers for nonautonomous spatially distributed periodic SIS models acting on two time scales.

    PubMed

    Marvá, M; Bravo de la Parra, R; Auger, P

    2012-06-01

    In this work we deal with a general class of spatially distributed periodic SIS epidemic models with two time scales. We let susceptible and infected individuals migrate between patches with periodic time dependent migration rates. The existence of two time scales in the system allows to describe certain features of the asymptotic behavior of its solutions with the help of a less dimensional, aggregated, system. We derive global reproduction numbers governing the general spatially distributed nonautonomous system through the aggregated system. We apply this result when the mass action law and the frequency dependent transmission law are considered. Comparing these global reproductive numbers to their non spatially distributed counterparts yields the following: adequate periodic migration rates allow global persistence or eradication of epidemics where locally, in absence of migrations, the contrary is expected.

  20. Periodic trim solutions with hp-version finite elements in time

    NASA Technical Reports Server (NTRS)

    Hou, Lin-Jun; Peters, David A.

    1991-01-01

    Finite elements in time as an alternative strategy for rotorcraft trim problems are studied. The research treats linear flap and linearized flap-lag response both for quasi-trim and trim cases. The connection between Fourier series analysis and hp-finite elements for periodic a problem is also examined. It is proved that Fourier series is a special case of space-time finite elements in which one element is used with a strong displacement formulation. Comparisons are made with respect to accuracy among Fourier analysis, displacement methods, and mixed methods over a variety parameters. The hp trade-off is studied for the periodic trim problem to provide an optimum step size and order of polynomial for a given error criteria. It is found that finite elements in time can outperform Fourier analysis for periodic problems, and for some given error criteria. The mixed method provides better results than does the displacement method.

  1. Environmental input and cognitive growth: a study using time-period comparisons.

    PubMed

    Huttenlocher, J; Levine, S; Vevea, J

    1998-08-01

    In this study, we examined the relation of input to cognitive growth in a single population of children. We studied 4 domains: Language, Spatial Operations, Concepts, and Associative Memory. Four groups of children drawn from the same population were tested in October of kindergarten, April of kindergarten, October of first grade, and April of first grade. These time points are 6 months apart, but they span periods that differ in amount of school input children receive. Much greater growth was found over time periods with greater amounts of school input (October to April) than over time periods with less school input (April to October) for Language, Spatial Operations, and Concepts, but not for Associative Memory. These findings suggest that amount of input is causally related to cognitive growth in particular domains.

  2. Identification of periods of clear sky irradiance in time series of GHI measurements

    DOE PAGES

    Reno, Matthew J.; Hansen, Clifford W.

    2016-01-18

    In this study, we present a simple algorithm for identifying periods of time with broadband global horizontal irradiance (GHI) similar to that occurring during clear sky conditions from a time series of GHI measurements. Other available methods to identify these periods do so by identifying periods with clear sky conditions using additional measurements, such as direct or diffuse irradiance. Our algorithm compares characteristics of the time series of measured GHI with the output of a clear sky model without requiring additional measurements. We validate our algorithm using data from several locations by comparing our results with those obtained from amore » clear sky detection algorithm, and with satellite and ground-based sky imagery.« less

  3. The Systemic Lupus International Collaborating Clinics (SLICC) group - it was 20 years ago today.

    PubMed

    Isenberg, D A; Ramsey-Goldman, R; Gladman, D; Hanly, J G

    2011-11-01

    The Systemic Lupus International Collaborating Clinics (SLICC) group is 20 years old this year (2011). This brief review traces the origins of the group focussing on its more recent history and reviewing some of its major contributions to lupus research during the past two decades.

  4. Intellectual Capital: For 20 Years, American Indian College Fund Has Been Investing

    ERIC Educational Resources Information Center

    Horwedel, Dina M.

    2009-01-01

    For 20 years, the American Indian College Fund (the Fund) has been helping students to afford a higher education. In addition to providing more than 4,000 scholarships for American Indian students last year, it also provides tribal colleges with funding and programmatic support. The Fund was created in 1989 by the tribal colleges and universities…

  5. Looking Back and Ahead: 20 Years of Technologies for Language Learning

    ERIC Educational Resources Information Center

    Godwin-Jones, Robert

    2016-01-01

    Over the last 20 years Robert Godwin-Jones has written 48 columns on "Emerging Technologies"; an additional six columns have been written by guest columnists. Several topics have been re-examined in regular intervals of approximately five years, namely digital literacy (Vol. 4, Num. 2; Vol. 10, Num. 2; Vol. 14, Num. 3; Vol. 19, Num. 3)…

  6. 20 Years of Autonomy and Technology: How Far Have We Come and Where to Next?

    ERIC Educational Resources Information Center

    Reinders, Hayo; White, Cynthia

    2016-01-01

    Learner autonomy has become an assumed goal of language education in many parts of the world. In the 20 years since the launch of "Language Learning & Technology," the relationship among computer-assisted language learning research and practice and autonomy has become both more complex and more promising. This article traces how the…

  7. Stature-for-Age and Weight-for-Age Percentiles: Boys, 2 to 20 Years

    MedlinePlus

    2 to 20 years: Boys NAME Stature-for-age and Weight-for-age percentiles RECORD # Mother’s Stature Date Age in cm 160 62 S 155 60 T 150 ... 14 15 16 17 18 19 20 BMI* AGE (YEARS) cm 95 190 90 185 75 180 ...

  8. Assessing Side Effects of Pharmacotherapy Treatment of Bipolar Disorder: A 20-Year Review of the Literature

    ERIC Educational Resources Information Center

    Matson, Johnny L.; Gonzalez, Melissa L.; Smith, Kimberly R.; Terlonge, Cindy; Thorson, Ryan T.; Dixon, Dennis R.

    2006-01-01

    A substantial literature on the effective treatment of bipolar disorder has begun to appear, particularly in the last 20 years.The majority of treatments studied have employed medications, particularly mood stabilizers, a typical antipsychotics and antidepressants. Most treatments produce side effects and medications are no exception. A review of…

  9. Q-Method 20 Years Later: Its Uses and Abuses in Communications Research.

    ERIC Educational Resources Information Center

    Freeman, Leonard

    William Stephenson's Q methodology has been linked to the future of communications research by some and condemned as treacherous by others. This study reviews the uses of Q in published mass communications research over the past 20 years. The survey found 30 mass communications studies published in English in the scholarly journals related to mass…

  10. Social Representations of Educability in Finland: 20 Years of Continuity and Change

    ERIC Educational Resources Information Center

    Raty, Hannu; Komulainen, Katri; Hirva, Laura

    2012-01-01

    This study set out to replicate a survey conducted 20 years ago on Finnish parents' social representations of educability. A nationwide sample of parents (N = 642) were asked to indicate their opinions on a set of statements pertaining to topical educational issues. The results indicated that educational discussion is still structured by two major…

  11. What Works: 20 Years of Curriculum Development and Research for Advanced Learners, 1988-2008

    ERIC Educational Resources Information Center

    VanTassel-Baska, Joyce, Ed.; Stambaugh, Tamra, Ed.

    2009-01-01

    The purpose of this document is to highlight "what works" based on the curriculum development and research work of the Center for Gifted Education during the past 20 years. Areas of study include curriculum development, instruction, assessment, and professional development. Through the use of the Integrated Curriculum Model as a template for …

  12. Changes and Challenges in 20 Years of Research into the Development of Executive Functions

    ERIC Educational Resources Information Center

    Hughes, Claire

    2011-01-01

    This review of 20 years of developmental research on Executive Functions (EF) offers a broad-brushstroke picture that touches on multiple issues including: (i) findings from typical and atypical groups, from infancy to adolescence; (ii) advances in assessment tools and in statistical analysis; (iii) the interplay between EF and other cognitive…

  13. 20 Years after "The Ontogeny of Human Memory: A Cognitive Neuroscience Perspective," Where Are We?

    ERIC Educational Resources Information Center

    Jabès, Adeline; Nelson, Charles A.

    2015-01-01

    In 1995, Nelson published a paper describing a model of memory development during the first years of life. The current article seeks to provide an update on the original work published 20 years ago. Specifically, we review our current knowledge on the relation between the emergence of explicit memory functions throughout development and the…

  14. Four Themes from 20 Years of Research on Infant Perception and Cognition

    ERIC Educational Resources Information Center

    Bremner, J. Gavin

    2011-01-01

    This paper reviews progress over the past 20 years in four areas of research on infant perception and cognition. Work on perception of dynamic events has identified perceptual constraints on perception of object unity and object trajectory continuity that have led to a perceptual account of early development that supplements Nativist accounts.…

  15. Understanding Rape and Sexual Assault: 20 Years of Progress and Future Directions

    ERIC Educational Resources Information Center

    Campbell, Rebecca; Wasco, Sharon M.

    2005-01-01

    During the past 20 years, researchers have documented the widespread problem of rape in American society. Approximately one in four women are raped in their adult lifetime, which causes severe psychological distress and long-term physical health problems. The impact of sexual assault extends far beyond rape survivors as their family, friends, and…

  16. Self-Rated Activity Levels and Longevity: Evidence from a 20 Year Longitudinal Study

    ERIC Educational Resources Information Center

    Mullee, Mark A.; Coleman, Peter G.; Briggs, Roger S. J.; Stevenson, James E.; Turnbull, Joanne C.

    2008-01-01

    The study reports on factors predicting the longevity of 328 people over the age of 65 drawn from an English city and followed over 20 years. Both the reported activities score and the individual's comparative evaluation of their own level of activity independently reduced the risk of death, even when health and cognitive status were taken into…

  17. 3D Heart Model and 4D Flow MRI 20 Years after Spiral Arterial Switch Operation

    PubMed Central

    Sievers, Hans-Hinrich; Kheradvar, Arash; Kramer, Hans-Heiner; Rickers, Carsten

    2016-01-01

    Case of a patient is presented here 20 years after spiral direct anastomosis of the great arteries in an arterial switch operation. Three-dimensional model of the heart combined with four-dimensional flow magnetic resonance imaging presents a novel comprehensive way to assess surgical results. PMID:28018823

  18. Reactive mesothelial hyperplasia associated with chronic peritonitis in a 20-year-old Quarter horse

    PubMed Central

    Hoon-Hanks, Laura L.; Rout, Emily D.; Vap, Linda M.; Aboellail, Tawfik A.; Hassel, Diana M.; Nout-Lomas, Yvette S.

    2016-01-01

    A 20-year-old gelding was diagnosed with peritonitis and severe reactive mesothelial hyperplasia. Exploratory laparotomy findings were suggestive of a neoplastic etiology; however, additional diagnostics ruled this out and the horse made a full recovery. This report demonstrates the difficulty and value of differentiating between reactive and neoplastic mesothelial processes. PMID:27152035

  19. Family Discord, Parental Depression, and Psychopathology in Offspring: 20-Year Follow-up

    ERIC Educational Resources Information Center

    Pilowsky, Daniel J.; Wickramaratne, Priya; Nomura, Yoko; Weissman, Myrna M.

    2006-01-01

    Objective: To determine the independent effects of parental depression and family discord on offspring psychopathology among children at high and low risk of depression. Method: Family discord factors were assessed when subjects were approximately 17 years old, and offspring diagnoses were assessed about 20 years later. Parental and offspring…

  20. In Patience and Hope: A 20-Year Narrative Study of a Family, School, and Community Partnership

    ERIC Educational Resources Information Center

    Higgins, Ann; Deegan, James G.

    2009-01-01

    This case study describes a 20-year journey of educational transformation from 1985 to 2005 in a bellwether, or highly developed, instance of one school, family, and community partnership--the Kileely Community Project--situated in a large social housing project in Limerick City in the Midwestern region of the Republic of Ireland. The study is a…

  1. College Student's Health, Drinking and Smoking Patterns: What Has Changed in 20 Years?

    ERIC Educational Resources Information Center

    Hensel, Desiree; Todd, Katherine Leigh; Engs, Ruth C.

    2014-01-01

    Problem: Institutes of higher learning are increasingly trying to address the issue of problem drinking. The purpose of this study was to determine how patterns in alcohol use and smoking by college students, as well as their illness patterns, have changed over 20 years. Methods: A cross-sectional serial survey design was used for this descriptive…

  2. The Politics of Educational Reform: The Alberta Charter School Experiment 20 Years Later

    ERIC Educational Resources Information Center

    Bosetti, Lynn; Butterfield, Phil

    2016-01-01

    In this paper we examine the public charter school movement in the Province of Alberta, Canada over the past 20 years to determine how charter school policy and regulations have limited and controlled the impact of charter schools on public education. Specifically we focus on the extent to which charter schools in Alberta fulfilled the aims and…

  3. Digital Distribution of Academic Journals and Its Impact on Scholarly Communication: Looking Back after 20 Years

    ERIC Educational Resources Information Center

    Solomon, David J.

    2013-01-01

    It has been approximately 20 years since distributing scholarly journals digitally became feasible. This article discusses the broad implications of the transition to digital distributed scholarship from a historical perspective and focuses on the development of open access (OA) and the various models for funding OA in the context of the roles…

  4. Iterative determination of invariant tori for a time-periodic Hamiltonian with two degrees of freedom

    SciTech Connect

    Gabella, W.E. Stanford Linear Accelerator Center, Stanford University, Stanford, Californi a 94309 ); Ruth, R.D.; Warnock, R.L. )

    1992-09-15

    We describe a nonperturbative numerical technique for solving the Hamilton-Jacobi equation of a nonlinear Hamiltonian system. We find the time-periodic solutions that yield accurate approximations to invariant tori. The method is suited to the case in which the perturbation to the underlying integrable system has a periodic and not necessarily smooth dependence on the time. This case is important in accelerator theory, where the perturbation is a periodic step function in time. The Hamilton-Jacobi equation is approximated by its finite-dimensional Fourier projection with respect to angle variables, then solved by Newton's method. To avoid Fourier analysis in time, which is not appropriate in the presence of step functions, we enforce time periodicity of solutions by a shooting algorithm. The method is tested in soluble models, and finally applied to a nonintegrable example, the transverse oscillations of a particle beam in a storage ring, in two degrees of freedom. In view of the time dependence of the Hamiltonian, this is a case with 21/2 degrees of freedom,'' in which phenomena like Arnol'd diffusion can occur.

  5. People's preference patterns for gains/losses in multiple time period situations.

    PubMed

    Chang, Shin-Shin; Chang, Jung-Hua

    2013-10-01

    Little research to date has been devoted to investigating whether people treat time differently from money when facing multiple gains or losses. This study tested the hypothesis that because time is characterized by perishability, fixed supply, and infungibility, people with strong motivation to obtain a long period of uninterrupted discretionary time would strive to trim the time needed for non-discretionary activities or to combine several non-discretionary activities. As a result, people prefer integration over segregation of multiple time losses or gains, which is not consistent with the prediction based on hedonic editing theory or the renewable resource model. This proposition is supported by results from four experiments.

  6. 20 years of ClO measurements in the Antarctic lower stratosphere

    NASA Astrophysics Data System (ADS)

    Nedoluha, Gerald E.; Connor, Brian J.; Mooney, Thomas; Barrett, James W.; Parrish, Alan; Gomez, R. Michael; Boyd, Ian; Allen, Douglas R.; Kotkamp, Michael; Kremser, Stefanie; Deshler, Terry; Newman, Paul; Santee, Michelle L.

    2016-08-01

    We present 20 years (1996-2015) of austral springtime measurements of chlorine monoxide (ClO) over Antarctica from the Chlorine Oxide Experiment (ChlOE1) ground-based millimeter wave spectrometer at Scott Base, Antarctica, as well 12 years (2004-2015) of ClO measurements from the Aura Microwave Limb Sounder (MLS). From August onwards we observe a strong increase in lower stratospheric ClO, with a peak column amount usually occurring in early September. From mid-September onwards we observe a strong decrease in ClO. In order to study interannual differences, we focus on a 3-week period from 28 August to 17 September for each year and compare the average column ClO anomalies. These column ClO anomalies are shown to be highly correlated with the average ozone mass deficit for September and October of each year. We also show that anomalies in column ClO are strongly anti-correlated with 30 hPa temperature anomalies, both on a daily and an interannual timescale. Making use of this anti-correlation we calculate the linear dependence of the interannual variations in column ClO on interannual variations in temperature. By making use of this relationship, we can better estimate the underlying trend in the total chlorine (Cly = HCl + ClONO2 + HOCl + 2 × Cl2 + 2 × Cl2O2 + ClO + Cl). The resultant trends in Cly, which determine the long-term trend in ClO, are estimated to be -0.5 ± 0.2, -1.4 ± 0.9, and -0.6 ± 0.4 % year-1, for zonal MLS, Scott Base MLS (both 2004-2015), and ChlOE (1996-2015) respectively. These trends are within 1σ of trends in stratospheric Cly previously found at other latitudes. The decrease in ClO is consistent with the trend expected from regulations enacted under the Montreal Protocol.

  7. 20 Years of ClO Measurements in the Antarctic Lower Stratosphere

    NASA Technical Reports Server (NTRS)

    Nedoluha, Gerald E.; Connor, Brian J.; Mooney, Thomas; Barrett, James W.; Parrish, Alan; Gomez, R. Michael; Boyd, Ian; Allen, Douglas R.; Kotkamp, Michael; Kremser, Stefanie; Deshler, Terry; Newman, Paul; Santee, Michelle L.

    2016-01-01

    We present 20 years (1996-2015) of austral springtime measurements of chlorine monoxide (ClO) over Antarctica from the Chlorine Oxide Experiment (ChlOEl) ground-based millimeter wave spectrometer at Scott Base, Antarctica, as well 12 years (2004-2015) of ClO measurements from the Aura Microwave Limb Sounder (MLS). From August onwards we observe a strong increase in lower stratospheric ClO, with a peak column amount usually occurring in early September. From mid-September onwards we observe a strong decrease in ClO. In order to study interannual differences, we focus on a 3-week period from 28 August to 17 September for each year and compare the average column ClO anomalies. These column ClO anomalies are shown to be highly correlated with the average ozone mass deficit for September and October of each year. We also show that anomalies in column ClO are strongly anti-correlated with 30 hPa temperature anomalies, both on a daily and an interannual timescale. Making use of this anti-correlation we calculate the linear dependence of the interannual variations in column C1O on interannual variations in temperature. By making use of this relationship, we can better estimate the underlying trend in the total chlorine (Cl(sub y) = HCl + ClONO2 + HOCl + 2 x Cl2 + 2 x Cl2+ ClO + Cl). The resultant trends in Cl(sub y), which determine the long-term trend in ClO, are estimated to be -0.5 +/-0.2, -1.40.9, and -0.60.4% per year, for zonal MLS, Scott Base MLS (both 2004-2015), and ChlOE (1996-2015) respectively. These trends are within 1sigma of trends in stratospheric Cl(sub y) previously found at other latitudes. The decrease in ClO is consistent with the trend expected from regulations enacted under the Montreal Protocol.

  8. DUACS DT2014: the new multi-mission altimeter data set reprocessed over 20 years

    NASA Astrophysics Data System (ADS)

    Pujol, Marie-Isabelle; Faugère, Yannice; Taburet, Guillaume; Dupuy, Stéphanie; Pelloquin, Camille; Ablain, Michael; Picot, Nicolas

    2016-09-01

    The new DUACS DT2014 reprocessed products have been available since April 2014. Numerous innovative changes have been introduced at each step of an extensively revised data processing protocol. The use of a new 20-year altimeter reference period in place of the previous 7-year reference significantly changes the sea level anomaly (SLA) patterns and thus has a strong user impact. The use of up-to-date altimeter standards and geophysical corrections, reduced smoothing of the along-track data, and refined mapping parameters, including spatial and temporal correlation-scale refinement and measurement errors, all contribute to an improved high-quality DT2014 SLA data set. Although all of the DUACS products have been upgraded, this paper focuses on the enhancements to the gridded SLA products over the global ocean. As part of this exercise, 21 years of data have been homogenized, allowing us to retrieve accurate large-scale climate signals such as global and regional MSL trends, interannual signals, and better refined mesoscale features.An extensive assessment exercise has been carried out on this data set, which allows us to establish a consolidated error budget. The errors at mesoscale are about 1.4 cm2 in low-variability areas, increase to an average of 8.9 cm2 in coastal regions, and reach nearly 32.5 cm2 in high mesoscale activity areas. The DT2014 products, compared to the previous DT2010 version, retain signals for wavelengths lower than ˜ 250 km, inducing SLA variance and mean EKE increases of, respectively, +5.1 and +15 %. Comparisons with independent measurements highlight the improved mesoscale representation within this new data set. The error reduction at the mesoscale reaches nearly 10 % of the error observed with DT2010. DT2014 also presents an improved coastal signal with a nearly 2 to 4 % mean error reduction. High-latitude areas are also more accurately represented in DT2014, with an improved consistency between spatial coverage and sea ice edge

  9. A Time-Delayed Mathematical Model for Tumor Growth with the Effect of a Periodic Therapy.

    PubMed

    Xu, Shihe; Wei, Xiangqing; Zhang, Fangwei

    2016-01-01

    A time-delayed mathematical model for tumor growth with the effect of periodic therapy is studied. The establishment of the model is based on the reaction-diffusion dynamics and mass conservation law and is considered with a time delay in cell proliferation process. Sufficient conditions for the global stability of tumor free equilibrium are given. We also prove that if external concentration of nutrients is large the tumor will not disappear and the conditions under which there exist periodic solutions to the model are also determined. Results are illustrated by computer simulations.

  10. Developmental critical windows and sensitive periods as three-dimensional constructs in time and space.

    PubMed

    Burggren, Warren W; Mueller, Casey A

    2015-01-01

    A critical window (sensitive period) represents a period during development when an organism's phenotype is responsive to intrinsic or extrinsic (environmental) factors. Such windows represent a form of developmental phenotypic plasticity and result from the interaction between genotype and environment. Critical windows have typically been defined as comprising discrete periods in development with a distinct starting time and end time, as identified by experiments following an on and an off protocol. Yet in reality, periods of responsiveness during development are likely more ambiguous that depicted. Our goal is to extend the concept of the developmental critical window by introducing a three-dimensional construct in which time during development, dose of the stressor applied, and the resultant phenotypic modification can be utilized to more realistically define a critical window. Using the example of survival of the brine shrimp (Artemia franciscana) during exposure to different salinity levels during development, we illustrate that it is not just stressor dose or exposure time but the interaction of these two factors that results in the measured phenotypic change, which itself may vary within a critical window. We additionally discuss a systems approach to critical windows, in which the components of a developing system--whether they be molecular, physiological, or morphological--may show differing responses with respect to time and dose. Thus, the plasticity of each component may contribute to a broader overall system response.

  11. Developmental histories of perceived racial discrimination and diurnal cortisol profiles in adulthood: A 20-year prospective study.

    PubMed

    Adam, Emma K; Heissel, Jennifer A; Zeiders, Katharine H; Richeson, Jennifer A; Ross, Emily C; Ehrlich, Katherine B; Levy, Dorainne J; Kemeny, Margaret; Brodish, Amanda B; Malanchuk, Oksana; Peck, Stephen C; Fuller-Rowell, Thomas E; Eccles, Jacquelynne S

    2015-12-01

    Perceived racial discrimination (PRD) has been associated with altered diurnal cortisol rhythms in past cross-sectional research. We investigate whether developmental histories of PRD, assessed prospectively, are associated with adult diurnal cortisol profiles. One-hundred and twelve (N=50 Black, N=62 White) adults from the Maryland Adolescent Development in Context Study provided saliva samples in adulthood (at approximately age 32 years) at waking, 30min after waking, and at bedtime for 7 days. Diurnal cortisol measures were calculated, including waking cortisol levels, diurnal cortisol slopes, the cortisol awakening response (CAR), and average daily cortisol (AUC). These cortisol outcomes were predicted from measures of PRD obtained over a 20-year period beginning when individuals were in 7th grade (approximately age 12). Greater average PRD measured across the 20-year period predicted flatter adult diurnal cortisol slopes for both Black and White adults, and a lower CAR. Greater average PRD also predicted lower waking cortisol for Black, but not White adults. PRD experiences in adolescence accounted for many of these effects. When adolescent and young adult PRD are entered together predicting cortisol outcomes, PRD experiences in adolescence (but not young adulthood) significantly predicted flatter diurnal cortisol slopes for both Black and White adults. Adolescent, but not young adult PRD, also significantly predicted lower waking and lower average cortisol for Black adults. Young adult PRD was, however, a stronger predictor of the CAR, predicting a marginally lower CAR for Whites, and a significantly larger CAR for Blacks. Effects were robust to controlling for covariates including health behaviors, depression, income and parent education levels. PRD experiences interacted with parent education and income to predict aspects of the diurnal cortisol rhythm. Although these results suggest PRD influences on cortisol for both Blacks and Whites, the key findings

  12. A Simple Discrete Model of Brownian Motors: Time-periodic Markov Chains

    NASA Astrophysics Data System (ADS)

    Ge, Hao; Jiang, Da-Quan; Qian, Min

    2006-05-01

    In this paper, we consider periodically inhomogeneous Markov chains, which can be regarded as a simple version of physical model—Brownian motors. We introduce for them the concepts of periodical reversibility, detailed balance, entropy production rate and circulation distribution. We prove the equivalence of the following statements: The time-periodic Markov chain is periodically reversible; It is in detailed balance; Kolmogorov's cycle condition is satisfied; Its entropy production rate vanishes; Every circuit and its reversed circuit have the same circulation weight. Hence, in our model of Markov chains, the directed transport phenomenon of Brownian motors, i.e. the existence of net circulation, can occur only in nonequilibrium and irreversible systems. Moreover, we verify the large deviation property and the Gallavotti-Cohen fluctuation theorem of sample entropy production rates of the Markov chain.

  13. A Discontinuous Galerkin Time Domain Framework for Periodic Structures Subject to Oblique Excitation

    NASA Astrophysics Data System (ADS)

    Miller, Nicholas C.; Baczewski, Andrew D.; Albrecht, John D.; Shanker, Balasubramaniam

    2014-08-01

    A nodal Discontinuous Galerkin (DG) method is derived for the analysis of time-domain (TD) scattering from doubly periodic PEC/dielectric structures under oblique interrogation. Field transformations are employed to elaborate a formalism that is free from any issues with causality that are common when applying spatial periodic boundary conditions simultaneously with incident fields at arbitrary angles of incidence. An upwind numerical flux is derived for the transformed variables, which retains the same form as it does in the original Maxwell problem for domains without explicitly imposed periodicity. This, in conjunction with the amenability of the DG framework to non-conformal meshes, provides a natural means of accurately solving the first order TD Maxwell equations for a number of periodic systems of engineering interest. Results are presented that substantiate the accuracy and utility of our method.

  14. Transient times and periods in the high-dimensional shape-space model for immune systems

    NASA Astrophysics Data System (ADS)

    Zorzenon dos Santos, Rita Maria

    1993-05-01

    A simplified version of the cellular automata approximation introduced by De Boer, Segel and Perelson in the shape-space model, to describe the interaction of different types of B cells in the immune system, indicates the existence of a threshold separating the periodic regime from the chaotic one, on high-dimensional finite lattices. We study the behavior of the periods of the limit cycles nearby the transition threshold as well as the behavior of the transient times necessary to attain the attractors in the periodic regime. We find that both become large close to the threshold. We also find that even before the chaotic regime is reached, the system is already trapped in a sort of non-healthy state. Nevertheless the system will never attain it, because the transient times in this region are much larger than the usual average lifetime of the system.

  15. Molecular response properties from a Hermitian eigenvalue equation for a time-periodic Hamiltonian.

    PubMed

    Pawłowski, Filip; Olsen, Jeppe; Jørgensen, Poul

    2015-03-21

    The time-dependent Schrödinger equation for a time-periodic perturbation is recasted into a Hermitian eigenvalue equation, where the quasi-energy is an eigenvalue and the time-periodic regular wave function an eigenstate. From this Hermitian eigenvalue equation, a rigorous and transparent formulation of response function theory is developed where (i) molecular properties are defined as derivatives of the quasi-energy with respect to perturbation strengths, (ii) the quasi-energy can be determined from the time-periodic regular wave function using a variational principle or via projection, and (iii) the parametrization of the unperturbed state can differ from the parametrization of the time evolution of this state. This development brings the definition of molecular properties and their determination on par for static and time-periodic perturbations and removes inaccuracies and inconsistencies of previous response function theory formulations. The development where the parametrization of the unperturbed state and its time evolution may differ also extends the range of the wave function models for which response functions can be determined. The simplicity and universality of the presented formulation is illustrated by applying it to the configuration interaction (CI) and the coupled cluster (CC) wave function models and by introducing a new model-the coupled cluster configuration interaction (CC-CI) model-where a coupled cluster exponential parametrization is used for the unperturbed state and a linear parametrization for its time evolution. For static perturbations, the CC-CI response functions are shown to be the analytical analogues of the static molecular properties obtained from finite field equation-of-motion coupled cluster (EOMCC) energy calculations. The structural similarities and differences between the CI, CC, and CC-CI response functions are also discussed with emphasis on linear versus non-linear parametrizations and the size-extensivity of the obtained

  16. Real-time control of the period of individual ELMs by EC power on TCV

    NASA Astrophysics Data System (ADS)

    Felici, F.; Rossel, J. X.; Duval, B. P.; Coda, S.; Goodman, T. P.; Martin, Y.; Moret, J.-M.; Sauter, O.; the TCV Team

    2013-11-01

    The period of individual type-I edge-localized modes (ELMs) in TCV H-mode plasmas is controlled by real-time controlled application of electron cyclotron (EC) power close to the plasma pedestal. An ELM pacing algorithm, closely related to sawtooth pacing (Goodman et al (2011 Phys. Rev. Lett. 106 245002)) has been implemented in the TCV control system. This algorithm switches the EC power to a low level after detecting an ELM, and subsequently increases the power to a higher level after a pre-set time interval, stimulating the advent of the next ELM. While the mean ELM period is observed to depend only on the mean power applied, ELM pacing is shown to significantly regularize the ELM period with respect to the case of continuously applied power. It is also shown that the ELM period can be changed from one ELM to the next on time scales shorter than the global energy confinement time. These results present a challenging benchmark to physics-based pedestal models and can point towards obtaining a deeper understanding of the physics of individual ELM cycles.

  17. 33 CFR 164.55 - Deviations from rules: Continuing operation or period of time.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Deviations from rules: Continuing operation or period of time. 164.55 Section 164.55 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY NAVIGATION SAFETY REGULATIONS §...

  18. 9 CFR 201.217 - Reasonable period of time to remedy a breach of contract.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Reasonable period of time to remedy a breach of contract. 201.217 Section 201.217 Animals and Animal Products GRAIN INSPECTION, PACKERS AND... termination. These criteria do not limit a packer, swine contractor or live poultry dealer's rights under...

  19. 9 CFR 201.217 - Reasonable period of time to remedy a breach of contract.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Reasonable period of time to remedy a breach of contract. 201.217 Section 201.217 Animals and Animal Products GRAIN INSPECTION, PACKERS AND... termination. These criteria do not limit a packer, swine contractor or live poultry dealer's rights under...

  20. Identifying the Critical Time Period for Information Extraction when Recognizing Sequences of Play

    ERIC Educational Resources Information Center

    North, Jamie S.; Williams, A. Mark

    2008-01-01

    The authors attempted to determine the critical time period for information extraction when recognizing play sequences in soccer. Although efforts have been made to identify the perceptual information underpinning such decisions, no researchers have attempted to determine "when" this information may be extracted from the display. The authors…

  1. 41 CFR 105-8.150-3 - Time period for compliance.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 41 Public Contracts and Property Management 3 2011-01-01 2011-01-01 false Time period for compliance. 105-8.150-3 Section 105-8.150-3 Public Contracts and Property Management Federal Property Management Regulations System (Continued) GENERAL SERVICES ADMINISTRATION 8-ENFORCEMENT OF...

  2. The Role of Thermal Properties in Periodic Time-Varying Phenomena

    ERIC Educational Resources Information Center

    Marin, E.

    2007-01-01

    The role played by physical parameters governing the transport of heat in periodical time-varying phenomena within solids is discussed. Starting with a brief look at the conduction heat transport mechanism, the equations governing heat conduction under static, stationary and non-stationary conditions, and the physical parameters involved, are…

  3. Practitioners' Perceptions of the Soccer Extra-Time Period: Implications for Future Research.

    PubMed

    Harper, Liam D; Fothergill, Melissa; West, Daniel J; Stevenson, Emma; Russell, Mark

    2016-01-01

    Qualitative research investigating soccer practitioners' perceptions can allow researchers to create practical research investigations. The extra-time period of soccer is understudied compared to other areas of soccer research. Using an open-ended online survey containing eleven main and nine sub questions, we gathered the perceptions of extra-time from 46 soccer practitioners, all working for different professional soccer clubs. Questions related to current practices, views on extra-time regulations, and ideas for future research. Using inductive content analysis, the following general dimensions were identified: 'importance of extra-time', 'rule changes', 'efficacy of extra-time hydro-nutritional provision', 'nutritional timing', 'future research directions', 'preparatory modulations' and 'recovery'. The majority of practitioners (63%) either agreed or strongly agreed that extra-time is an important period for determining success in knockout football match-play. When asked if a fourth substitution should be permitted in extra-time, 67% agreed. The use of hydro-nutritional strategies prior to extra-time was predominately considered important or very important. However; only 41% of practitioners felt that it was the most important time point for the use of nutritional products. A similar number of practitioners account (50%) and do not (50%) account for the potential of extra-time when training and preparing players and 89% of practitioners stated that extra-time influences recovery practices following matches. In the five minute break prior to extra-time, the following practices (in order of priority) were advocated to players: hydration, energy provision, massage, and tactical preparations. Additionally, 87% of practitioners advocate a particular nutritional supplementation strategy prior to extra-time. In order of importance, practitioners see the following as future research areas: nutritional interventions, fatigue responses, acute injury risk, recovery

  4. Particle Fluxes in the Marginal Seas of Antarctica: A 20-year Synthesis in Honor of Jack Dymond

    NASA Astrophysics Data System (ADS)

    Dunbar, R. B.; Langone, L.

    2004-12-01

    One of Jack Dymond's long-standing scientific passions was the study of particles moving through the ocean water column. Jack's pioneering work in this area in the 1970's and generous mentoring of others throughout his career lead directly to the first authors involvement in sediment trap studies. Here we present a synthesis of 20 years of particle flux studies in coastal Antarctic (including the work of Collier and Dymond et al.) and highlight some of the important features and unresolved issues related to integrating particle trap interceptor data with other measures of production, transport, and deposition. The first sediment trap arrays were deployed on the Antarctic shelf in 1981 and 1982 in the Antarctic Peninsula. Simple instruments were also deployed in 1984 and 1986 in the Ross Sea. Since then, several nations (US, Italy, New Zealand) have recovered time series sediment trap data on moorings in both of these areas. This current synthesis makes use of data from approximately 22 sites, the majority of which are in the Ross Sea, and includes about 900 discrete samples of particles in vertical transit through the water column. We now have many complete time series that extend through the winter, allowing several important generalizations to be made. For example, annual particle-mediated organic C fluxes to below 200 meters in the Ross Sea average 4.4±3.3 g C m-2 yr-1. These values are significantly less than export fluxes calculated using short-term surface water mass balance approaches or Th isotope techniques yet are higher than seabed sediment accumulation rates. Intriguingly, seasonal seabed arrival rates of organic C estimated from in-situ summertime benthic respirometry studies yield C flux values similar in magnitude to those from sediment traps deployed at the same time, lending strong support to trap data. The cause of current disagreements between various methods of flux estimation may in fact not be solved until process studies are accomplished

  5. Reliability of Fitness Tests Using Methods and Time Periods Common in Sport and Occupational Management

    PubMed Central

    Burnstein, Bryan D.; Steele, Russell J.; Shrier, Ian

    2011-01-01

    Context: Fitness testing is used frequently in many areas of physical activity, but the reliability of these measurements under real-world, practical conditions is unknown. Objective: To evaluate the reliability of specific fitness tests using the methods and time periods used in the context of real-world sport and occupational management. Design: Cohort study. Setting: Eighteen different Cirque du Soleil shows. Patients or Other Participants: Cirque du Soleil physical performers who completed 4 consecutive tests (6-month intervals) and were free of injury or illness at each session (n = 238 of 701 physical performers). Intervention(s): Performers completed 6 fitness tests on each assessment date: dynamic balance, Harvard step test, handgrip, vertical jump, pull-ups, and 60-second jump test. Main Outcome Measure(s): We calculated the intraclass coefficient (ICC) and limits of agreement between baseline and each time point and the ICC over all 4 time points combined. Results: Reliability was acceptable (ICC > 0.6) over an 18-month time period for all pairwise comparisons and all time points together for the handgrip, vertical jump, and pull-up assessments. The Harvard step test and 60-second jump test had poor reliability (ICC < 0.6) between baseline and other time points. When we excluded the baseline data and calculated the ICC for 6-month, 12-month, and 18-month time points, both the Harvard step test and 60-second jump test demonstrated acceptable reliability. Dynamic balance was unreliable in all contexts. Limit-of-agreement analysis demonstrated considerable intraindividual variability for some tests and a learning effect by administrators on others. Conclusions: Five of the 6 tests in this battery had acceptable reliability over an 18-month time frame, but the values for certain individuals may vary considerably from time to time for some tests. Specific tests may require a learning period for administrators. PMID:22488138

  6. Time-averaged properties of unstable periodic orbits and chaotic orbits in ordinary differential equation systems.

    PubMed

    Saiki, Yoshitaka; Yamada, Michio

    2009-01-01

    It has recently been found in some dynamical systems in fluid dynamics that only a few unstable periodic orbits (UPOs) with low periods can give good approximations to the mean properties of turbulent (chaotic) solutions. By employing three chaotic systems described by ordinary differential equations, we compare time-averaged properties of a set of UPOs and those of a set of segments of chaotic orbits. For every chaotic system we study, the distributions of a time average of a dynamical variable along UPOs with lower and higher periods are similar to each other and the variance of the distribution is small, in contrast with that along chaotic segments. The distribution seems to converge to some limiting distribution with nonzero variance as the period of the UPO increases, although that along chaotic orbits inclines to converge to a delta -like distribution. These properties seem to lie in the background of why only a few UPOs with low periods can give good mean statistical properties in dynamical systems in fluid dynamics.

  7. Time Evolution of low-Frequency Periodicities in Cosmic ray Intensity

    NASA Astrophysics Data System (ADS)

    Kudela, K.; Rybák, J.; Antalová, A.; Storini, M.

    2002-01-01

    The long-time series of daily means of cosmic-ray intensity observed by four neutron monitors at different cutoff rigidities (Calgary, Climax, Lomnický Štít and Huancayo/Haleakala) were analyzed by means of the wavelet transform method in the period range ~60 to ~1000 days. The contributions of the time evolution of three quasi-periodic cosmic-ray signals (~150 d, ~1.3 yr and ~1.7 yr) to the global one are obtained. While the ~1.7-yr quasi-periodicity, the most remarkable one in the studied interval, strongly contributes to the cosmic ray intensity profile of solar cycle 21 (particularly in 1982), the ~1.3-yr one, which is better correlated with the same periodicity of the interplanetary magnetic field strength, is present as a characteristic feature for the decreasing phases of the cycles 20 and 22. Transitions between these quasi-periodicities are seen in the wavelet power spectra plots. Obtained results support the claimed difference in the solar activity evolution during odd and even solar activity cycles.

  8. Recurrence times and periodicities in 4U 1608-52 as observed by Vela 5B

    NASA Technical Reports Server (NTRS)

    Lochner, James C.; Roussel-Dupre, Diane

    1994-01-01

    We report on the Vela 5B 10 year history of the soft X-ray transient 4U 1608-52, and on the characteristics of its soft X-ray outbursts. The Vela 5B satellite observed the four known outbursts in 1975, 1977, and 1979, and four new outbursts in 1970 and 1971, altering the recurrence pattern of outbursts from this source. One of the 1970 outbursts is symmetric in its intensity profile, while the two outbursts in 1971 have short exponential profiles separated by 80 days. Despite suggestive recurrence periods of approximately 85 and approximately 150 days evident in the time intervals between the outbursts, there is no single statistically significant recurrence time on which the outbursts recur consistently. In the 1970 symmetric event, there is evidence for a period of either 4.10 or 5.19 days. Drawing upon the analogy with SU Ursa Majoris dwarf novae, we suggest that the short period is orbital and any longer period would be associated with a precession period of the accretion disk.

  9. Efficient Fourier-based algorithms for time-periodic unsteady problems

    NASA Astrophysics Data System (ADS)

    Gopinath, Arathi Kamath

    2007-12-01

    This dissertation work proposes two algorithms for the simulation of time-periodic unsteady problems via the solution of Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations. These algorithms use a Fourier representation in time and hence solve for the periodic state directly without resolving transients (which consume most of the resources in a time-accurate scheme). In contrast to conventional Fourier-based techniques which solve the governing equations in frequency space, the new algorithms perform all the calculations in the time domain, and hence require minimal modifications to an existing solver. The complete space-time solution is obtained by iterating in a fifth pseudo-time dimension. Various time-periodic problems such as helicopter rotors, wind turbines, turbomachinery and flapping-wings can be simulated using the Time Spectral method. The algorithm is first validated using pitching airfoil/wing test cases. The method is further extended to turbomachinery problems, and computational results verified by comparison with a time-accurate calculation. The technique can be very memory intensive for large problems, since the solution is computed (and hence stored) simultaneously at all time levels. Often, the blade counts of a turbomachine are rescaled such that a periodic fraction of the annulus can be solved. This approximation enables the solution to be obtained at a fraction of the cost of a full-scale time-accurate solution. For a viscous computation over a three-dimensional single-stage rescaled compressor, an order of magnitude savings is achieved. The second algorithm, the reduced-order Harmonic Balance method is applicable only to turbomachinery flows, and offers even larger computational savings than the Time Spectral method. It simulates the true geometry of the turbomachine using only one blade passage per blade row as the computational domain. In each blade row of the turbomachine, only the dominant frequencies are resolved, namely

  10. THE VARYING LIGHT CURVE AND TIMINGS OF THE ULTRASHORT-PERIOD CONTACT BINARY KIC 9532219

    SciTech Connect

    Lee, Jae Woo; Hong, Kyeongsoo; Koo, Jae-Rim; Park, Jang-Ho E-mail: kshong@kasi.re.kr E-mail: pooh107162@kasi.re.kr

    2016-03-20

    KIC 9532219 is a W UMa-type eclipsing binary with an orbital period of 0.1981549 days that is below the short-period limit (∼0.22 days) of the period distribution for contact binaries. The Kepler light curve of the system exhibits striking changes in both eclipse depths and light maxima. Applying third-body and spot effects, the light-curve synthesis indicates that the eclipsing pair is currently in a marginal contact stage with a mass ratio of q = 1.20, an orbital inclination of i = 66.°0, a temperature difference of T{sub 1}–T{sub 2} = 172 K, and a third light of l{sub 3} = 75.9%. To understand the light variations with time, we divided up the light curve into 312 segments and analyzed them separately. The results reveal that variation of eclipse depth is primarily caused by changing amounts of contamination due to the nearby star KIC 9532228 between the Kepler Quarters and that the variable O’Connell effect originates from the starspot activity on the less massive primary component. Based on our light-curve timings, a period study of KIC 9532219 indicates that the orbital period has varied as a combination of a downward parabola and a light-travel-time (LTT) effect due to a third body, which has a period of 1196 days and a minimum mass of 0.0892 M{sub ⊙} in an orbit of eccentricity 0.150. The parabolic variation could be a small part of a second LTT orbit due to a fourth component in a wider orbit, instead of either mass transfer or angular momentum loss.

  11. Sex difference in the near-24-hour intrinsic period of the human circadian timing system

    PubMed Central

    Duffy, Jeanne F.; Cain, Sean W.; Chang, Anne-Marie; Phillips, Andrew J. K.; Münch, Mirjam Y.; Gronfier, Claude; Wyatt, James K.; Dijk, Derk-Jan; Czeisler, Charles A.

    2011-01-01

    The circadian rhythms of melatonin and body temperature are set to an earlier hour in women than in men, even when the women and men maintain nearly identical and consistent bedtimes and wake times. Moreover, women tend to wake up earlier than men and exhibit a greater preference for morning activities than men. Although the neurobiological mechanism underlying this sex difference in circadian alignment is unknown, multiple studies in nonhuman animals have demonstrated a sex difference in circadian period that could account for such a difference in circadian alignment between women and men. Whether a sex difference in intrinsic circadian period in humans underlies the difference in circadian alignment between men and women is unknown. We analyzed precise estimates of intrinsic circadian period collected from 157 individuals (52 women, 105 men; aged 18–74 y) studied in a month-long inpatient protocol designed to minimize confounding influences on circadian period estimation. Overall, the average intrinsic period of the melatonin and temperature rhythms in this population was very close to 24 h [24.15 ± 0.2 h (24 h 9 min ± 12 min)]. We further found that the intrinsic circadian period was significantly shorter in women [24.09 ± 0.2 h (24 h 5 min ± 12 min)] than in men [24.19 ± 0.2 h (24 h 11 min ± 12 min); P < 0.01] and that a significantly greater proportion of women have intrinsic circadian periods shorter than 24.0 h (35% vs. 14%; P < 0.01). The shorter average intrinsic circadian period observed in women may have implications for understanding sex differences in habitual sleep duration and insomnia prevalence. PMID:21536890

  12. GNSS related periodic signals in coordinate time-series from Precise Point Positioning

    NASA Astrophysics Data System (ADS)

    Abraha, K. E.; Teferle, F. N.; Hunegnaw, A.; Dach, R.

    2017-03-01

    In Global Navigation Satellite System (GNSS) coordinate time-series unrecognized errors and unmodelled (periodic) effects may bias nonlinear motions induced by geophysical signals. Hence, understanding and mitigating these errors is vital to reducing biases and on revealing subtle geophysical signals. To assess the nature of periodic signals in coordinate time-series Precise Point Positioning (PPP) solutions for the period 2008-2015 are generated. The solutions consider Global Positioning System (GPS), GLObalnaya NAvigatsionnaya Sputnikovaya Sistema (GLONASS) or combined GPS+GLONASS (GNSS) observations. We assess the periodic signals of station coordinates computed using the combined International GNSS Service (IGS) and four of its Analysis Centers (ACs) products. Furthermore, we make use of different filtering methods to investigate the sources of the periodic signals. A faint fortnightly signal in our PPP solution based on Jet Propulsion Laboratory (JPL) products and the existence of an 8 d period for those ACs generating combined GPS+GLONASS products are the main features in the GPS-only solutions. The existence of the 8 d period in the GPS-only solution indicates that GPS orbits computed in a combined GNSS solution contain GLONASS-specific signals. The GLONASS-only solution shows highly elevated powers at the third draconitic harmonic (˜120 d period), at the 8 d period and its harmonics (4 d, 2.67 d) besides the well-known annual, semi-annual and other draconitic harmonics. We show that the GLONASS constellation gaps before December 2011 contribute to the power at some of the frequencies. However, the well-known fortnightly signal in GPS-only solutions is not discernible in the GLONASS-only solution. The combined GNSS solution contains periodic signals from both systems, with most of the powers being reduced when compared to the single-GNSS solutions. A 52 per cent reduction for the horizontal components and a 36 per cent reduction for the vertical component

  13. Periodic modulation in pulse arrival times from young pulsars: a renewed case for neutron star precession

    NASA Astrophysics Data System (ADS)

    Kerr, M.; Hobbs, G.; Johnston, S.; Shannon, R. M.

    2016-01-01

    In a search for periodic variation in the arrival times of pulses from 151 young, energetic pulsars, we have identified seven cases of modulation consistent with one or two harmonics of a single fundamental with time-scale 0.5-1.5 yr. We use simulations to show that these modulations are statistically significant and of high quality (sinusoidal) even when contaminated by the strong stochastic timing noise common to young pulsars. Although planetary companions could induce such modulation, the large implied masses and 2:1 mean motion resonances challenge such an explanation. Instead, the modulation is likely to be intrinsic to the pulsar, arising from quasi-periodic switching between stable magnetospheric states, and we propose that precession of the neutron star may regulate this switching.

  14. The effect of entrainment on the timing of periodic eye movements.

    PubMed

    Richardson, Brian A; Balasubramaniam, Ramesh

    2010-01-18

    We performed an experiment in which eight healthy individuals made periodic eye movements at five pacing interval conditions (500 ms, 750 ms, 1000 ms, 1250 ms, and 1500 ms). Three methods of entrainment were used in the synchronization phase: saccade, continuous pursuit and discontinuous pursuit. The stimulus train was extinguished and in the continuation phase, subjects made saccadic eye movements at the entrained movement frequencies between two static targets. Using the Wing-Kristofferson model, clock and motor variance were extracted from the time series of continuation trials for all three entrainment conditions. Our results revealed a main effect of time interval on total variance clock variance (as predicted by Weber's law) and on motor variance. We also report that the pursuit entrainment conditions resulted in and mean duration and variance to the saccade entrainment. These results suggest that the neural networks recruited to support a periodic motor timing task depend on the method used to establish the temporal reference.

  15. The quantum fidelity for the time-periodic singular harmonic oscillator

    NASA Astrophysics Data System (ADS)

    Combescure, Monique

    2006-03-01

    In this paper we perform an exact study of "quantum fidelity" (also called Loschmidt echo) for the time-periodic quantum harmonic oscillator of the following Hamiltonian: Ĥg(t)≔(P2/2)+f(t)(Q2/2)+(g2/Q2), when compared with the quantum evolution induced by Ĥ0(t) (g=0), in the case where f is a T-periodic function and g a real constant. The reference (initial) state is taken to be an arbitrary "generalized coherent state" in the sense of Perelomov. We show that, starting with a quadratic decrease in time in the neighborhood of t =0, this quantum fidelity may recur to its initial value 1 at an infinite sequence of times tk. We discuss the result when the classical motion induced by Hamiltonian Ĥ0(t) is assumed to be stable versus unstable.

  16. Association of intrinsic circadian period with morningness-eveningness, usual wake time, and circadian phase

    NASA Technical Reports Server (NTRS)

    Duffy, J. F.; Rimmer, D. W.; Czeisler, C. A.

    2001-01-01

    The biological basis of preferences for morning or evening activity patterns ("early birds" and "night owls") has been hypothesized but has remained elusive. The authors reported that, compared with evening types, the circadian pacemaker of morning types was entrained to an earlier hour with respect to both clock time and wake time. The present study explores a chronobiological mechanism by which the biological clock of morning types may be set to an earlier hour. Intrinsic period, a fundamental property of the circadian system, was measured in a month-long inpatient study. A subset of participants also had their circadian phase assessed. Participants completed a morningness-eveningness questionnaire before study. Circadian period was correlated with morningness-eveningness, circadian phase, and wake time, demonstrating that a fundamental property of the circadian pacemaker is correlated with the behavioral trait of morningness-eveningness.

  17. Estimating Periodic Software Rejuvenation Schedules under Discrete-Time Operation Circumstance

    NASA Astrophysics Data System (ADS)

    Iwamoto, Kazuki; Dohi, Tadashi; Kaio, Naoto

    Software rejuvenation is a preventive and proactive solution that is particularly useful for counteracting the phenomenon of software aging. In this article, we consider periodic software rejuvenation models based on the expected cost per unit time in the steady state under discrete-time operation circumstance. By applying the discrete renewal reward processes, we describe the stochastic behavior of a telecommunication billing application with a degradation mode, and determine the optimal periodic software rejuvenation schedule minimizing the expected cost. Similar to the earlier work by the same authors, we develop a statistically non-parametric algorithm to estimate the optimal software rejuvenation schedule, by applying the discrete total time on test concept. Numerical examples are presented to estimate the optimal software rejuvenation schedules from the simulation data. We discuss the asymptotic behavior of estimators developed in this paper.

  18. Periodic trim solutions with HP-version finite elements in time

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Finite Element in Time has been proven to be a powerful alternative solving strategy for the rotor craft trim problem. Additionally, Finite Element Method in Time has been developed in various versions like time-marching framework, Galerkin framework, Rayleigh-Ritz framework, and mixed formulation. Recently, this method was applied to the rotorcraft trim problem to obtain linearized solutions. The rotorcraft trim problem consists of trying to find a period solution for period-coefficient, differential equations subject to side constraints where certain force and momentum balance equations are forced to be equal to zero. There are free (or trim) parameters that are chosen to meet these side constraints. This project aims at expanding the application, in terms of the rotorcraft trim problem, from a linearized solution to nonlinear solution.

  19. Neurotoxicity in young adults 20 years after childhood exposure to lead: the Bunker Hill experience

    PubMed Central

    Stokes, L.; Letz, R.; Gerr, F.; Kolczak, M.; McNeill, F. E.; Chettle, D. R.; Kaye, W. E.

    1998-01-01

    OBJECTIVES: An epidemiological study of young adults was conducted to determine whether environmental exposure to lead during childhood was associated with current adverse neurobehavioural effects. METHODS: The exposed group consisted of 281 young adults who had been exposed environmentally to lead as children and the unexposed referent group consisted of 287 age and sex frequency matched subjects. Information on demographics, past and current health, and past exposures to neurotoxicants, and responses to the Swedish Q16 questionnaire were collected by interview. Standard neurobehavioural and neurophysiological tests were administered by computer or trained technicians. K x ray fluorescence was used to estimate tibial bone lead concentrations among the exposed and unexposed groups. Associations were examined between the exposed group and referents and tibial bone lead concentration and the neurobehavioural and neurophysiological outcomes of interest. RESULTS: Among the measures of peripheral nerve function, after controlling for confounders, sural sensory nerve evoked response amplitude, peroneal motor nerve compound motor action potential amplitude, vibrotactile thresholds of fingers and toes, and standing steadiness were significantly associated with exposure group. Among the neurobehavioural tests, hand-eye coordination, simple reaction time latency, trails B latency, symbol digit latency, serial digit, and learning error score were also significantly associated with exposure group after controlling for confounders. Exposed subjects had significantly more neuropsychiatric symptoms than the referents. Associations between tibial bone lead concentration and scores for vocabulary, vibrotactile thresholds of the fingers, and vibrotactile thresholds of the toes approached significance. CONCLUSIONS: Significant adverse central and peripheral neurological effects were found in a group of young adults 20 years after childhood environmental exposure to lead when compared

  20. Spinal cord stimulation: a 20-year retrospective analysis in 260 patients.

    PubMed

    Reig, Enrique; Abejón, David

    2009-07-01

    Introduction. Spinal cord stimulation (SCS) is used clinically by many pain physicians and neurosurgeons alike without regard to their own outcome data. Methods. We reviewed our 20-year experience retrospectively of patients receiving SCS implants and analyzed our data by pain type and group. Results. We present 260 patients, 140 men and 120 women. The most frequent type of pain in our series was neuropathic pain in 44.25% and the most frequent diagnosis was peripheral vascular disease (PVD) with 98 cases. The second was failed back surgery syndrome (FBSS) with 65 cases and the third was complex regional pain syndrome type I (CRPS I), with 40 cases. In CRPS group, the mean visual analog scale (VAS) of this group was 77.89 ± 13.38. In total, 5% had no pain relief, 40% had poor pain relief, 47.5% had good pain relief, and 7.5% had excellent pain relief. In FBSS group, the mean VAS was 79.62 ± 11.69 mm. A total of 13.80% had no pain relief at all, 35.39% had poor pain relief, 50.76% had good pain relief, and there were no patients in this group who had complete pain relief. A total of 98 patients, 78 men and 20 women, were diagnosed with PVD. The mean VAS of this group was 69.75 ± 14.36 mm. A total of 11.22% had poor pain relief, 87.75% had good pain relief. One patient had complete pain relief and all patients in this group perceived at least some improvement in their symptoms. The rate of complications was close to 28% in our overall sample. Conclusions. In conclusion, we demonstrated the utility over time of this type of treatment is comparable with other series of efficacy of SCS. The analgesic efficacy was close to 65% in the overall group. The therapy was not free of complications. The preponderance of our patients was patients with the diagnosis of PVD and our results in this group of patients were excellent. These excellent results of more than 90% improvement suggest to us that SCS be considered as a first-line approach to the

  1. Lung biopsies and patient care at university-affiliated hospitals: a 20-year experience.

    PubMed Central

    Collins, J. D.

    1990-01-01

    Lung biopsies have been performed since 1967 at the University of California at Los Angeles and its affiliated institutions. In the span of 20 years, the author performed 4285 cases and developed several procedures. This article discusses the importance of risk management and patient care and presents statistics on malignancies, complications, and contraindications. Images Figure 1A Figure 1B Figure 2A Figure 2B PMID:2398507

  2. Chinese medicines reported to have effects on contact dermatitis in the last 20 years.

    PubMed

    Jung, Youngchul; Kim, Byungju; Ryu, Mi Heon; Kim, Hyungwoo

    2017-03-02

    Contact dermatitis (CD) is one of the most common skin diseases in industrialized countries. Chinese medicines (CMs) have been investigated worldwide as complementary and alternative medicines for corticosteroids, which are the first choice for treatment of inflammatory skin diseases owing to their favorable efficacy. This article describes the CMs that have been reported to have anti-dermatitis effects against CD in the last 20 years.

  3. [The Health Surveillance database of a large hospital enterprise: a 20-year analysis].

    PubMed

    Talini, Donatella; Baldasseronil, Alberto; Cristaudo, Alfonso; Magnani, Aldo

    2014-01-01

    To evaluate the aging of the working population and its effects, a 20 years observational study was conducted on health surveillance data of a large healthcare company. The data showed a gradual increase in the mean age of workers, especially among subjects with restrictions/requirements regarding their job title. If no preventive/corrective measures are taken, the socio-economnic situation will get worse with economic and social damages.

  4. 30 CFR 250.1161 - When may I flare or vent gas for extended periods of time?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... periods of time? 250.1161 Section 250.1161 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL... I flare or vent gas for extended periods of time? You must request and receive approval from the Regional Supervisor to flare or vent gas for an extended period of time. The Regional Supervisor...

  5. 30 CFR 250.1161 - When may I flare or vent gas for extended periods of time?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... periods of time? 250.1161 Section 250.1161 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL... I flare or vent gas for extended periods of time? You must request and receive approval from the Regional Supervisor to flare or vent gas for an extended period of time. The Regional Supervisor...

  6. 30 CFR 250.1161 - When may I flare or vent gas for extended periods of time?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... periods of time? 250.1161 Section 250.1161 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL... I flare or vent gas for extended periods of time? You must request and receive approval from the Regional Supervisor to flare or vent gas for an extended period of time. The Regional Supervisor...

  7. Epidemiology and sites of involvement of invasive fungal infections in patients with haematological malignancies: a 20-year autopsy study.

    PubMed

    Lewis, Russell E; Cahyame-Zuniga, Lizebeth; Leventakos, Konstantinos; Chamilos, Georgios; Ben-Ami, Ronen; Tamboli, Pheroze; Tarrand, Jeffrey; Bodey, Gerald P; Luna, Mario; Kontoyiannis, Dimitrios P

    2013-11-01

    Autopsy studies remain an essential tool for understanding the patterns of fungal disease not detected ante mortem with current diagnostic approaches. We collected data concerning the microbiological trends, patient clinical characteristics and sites of involvement for invasive fungal infections (IFIs) identified at autopsy in a single large cancer treatment centre over a 20-year period (1989-2008). The autopsy rate and IFI prevalence both declined significantly during the study period. The prevalence of Aspergillus spp. decreased significantly from the first 15 years of the study (from 0.12 to 0.14 cases per 100 autopsies to 0.07 in 2004-2008; P = 0.04), with only Mucorales accounting for a greater proportion of IFIs over the duration of the study period (0.06 to 0.2 cases per 100 autopsies, P = 0.04). After 2003, moulds accounted for the majority of infections identified at autopsy in the spleen, kidney, heart and gastrointestinal tract. Despite a trend of decreasing prevalence from 1989 to 2004, invasive candidiasis increased in prevalence during later periods 2004-2008 (0.02-0.05 per 100 autopsies) with decreasing kidney, heart and spleen involvement. Despite a declining autopsy rate, these data suggest a decreasing prevalence overall of IFIs with changing patterns of dissemination in patients with haematological malignancies.

  8. Dealing with periodical loads and harmonics in operational modal analysis using time-varying transmissibility functions

    NASA Astrophysics Data System (ADS)

    Weijtjens, Wout; Lataire, John; Devriendt, Christof; Guillaume, Patrick

    2014-12-01

    Periodical loads, such as waves and rotating machinery, form a problem for operational modal analysis (OMA). In OMA only the vibrations of a structure of interest are measured and little to nothing is known about the loads causing these vibrations. Therefore, it is often assumed that all dynamics in the measured data are linked to the system of interest. Periodical loads defy this assumption as their periodical behavior is often visible within the measured vibrations. As a consequence most OMA techniques falsely associate the dynamics of the periodical load with the system of interest. Without additional information about the load, one is not able to correctly differentiate between structural dynamics and the dynamics of the load. In several applications, e.g. turbines and helicopters, it was observed that because of periodical loads one was unable to correctly identify one or multiple modes. Transmissibility based OMA (TOMA) is a completely different approach to OMA. By using transmissibility functions to estimate the structural dynamics of the system of interest, all influence of the load-spectrum can be eliminated. TOMA therefore allows to identify the modal parameters without being influenced by the presence of periodical loads, such as harmonics. One of the difficulties of TOMA is that the analyst is required to find two independent datasets, each associated with a different loading condition of the system of interest. This poses a dilemma for TOMA; how can an analyst identify two different loading conditions when little is known about the loads on the system? This paper tackles that problem by assuming that the loading conditions vary continuously over time, e.g. the changing wind directions. From this assumption TOMA is developed into a time-varying framework. This development allows TOMA to not only cope with the continuously changing loading conditions. The time-varying framework also enables the identification of the modal parameters from a single dataset

  9. Synchronous HIV/AIDS-related Epstein-Barr Virus-associated smooth muscle tumors in a 20-year-old female.

    PubMed

    Adam, Etai; Wang, Larry; Herrington, Cynthia; Bliss, David; Church, Joseph A

    2014-10-01

    We present a case of simultaneous endobronchial and adrenal Epstein-Barr Virus-associated smooth muscle tumors in a 20-year-old female with AIDS. Blood Epstein-Barr Virus polymerase chain reaction was negative at the time of diagnosis.

  10. Depleted uranium contamination by inhalation exposure and its detection after approximately 20 years: implications for human health assessment.

    PubMed

    Parrish, Randall R; Horstwood, Matthew; Arnason, John G; Chenery, Simon; Brewer, Tim; Lloyd, Nicholas S; Carpenter, David O

    2008-02-01

    Inhaled depleted uranium (DU) aerosols are recognised as a distinct human health hazard and DU has been suggested to be responsible in part for illness in both military and civilian populations that may have been exposed. This study aimed to develop and use a testing procedure capable of detecting an individual's historic milligram-quantity aerosol exposure to DU up to 20 years after the event. This method was applied to individuals associated with or living proximal to a DU munitions plant in Colonie New York that were likely to have had a significant DU aerosol inhalation exposure, in order to improve DU-exposure screening reliability and gain insight into the residence time of DU in humans. We show using sensitive mass spectrometric techniques that when exposure to aerosol has been unambiguous and in sufficient quantity, urinary excretion of DU can be detected more than 20 years after primary DU inhalation contamination ceased, even when DU constitutes only approximately 1% of the total excreted uranium. It seems reasonable to conclude that a chronically DU-exposed population exists within the contamination 'footprint' of the munitions plant in Colonie, New York. The method allows even a modest DU exposure to be identified where other less sensitive methods would have failed entirely. This should allow better assessment of historical exposure incidence than currently exists.

  11. Stochastic model stationarization by eliminating the periodic term and its effect on time series prediction

    NASA Astrophysics Data System (ADS)

    Moeeni, Hamid; Bonakdari, Hossein; Fatemi, Seyed Ehsan

    2017-04-01

    Because time series stationarization has a key role in stochastic modeling results, three methods are analyzed in this study. The methods are seasonal differencing, seasonal standardization and spectral analysis to eliminate the periodic effect on time series stationarity. First, six time series including 4 streamflow series and 2 water temperature series are stationarized. The stochastic term for these series obtained with ARIMA is subsequently modeled. For the analysis, 9228 models are introduced. It is observed that seasonal standardization and spectral analysis eliminate the periodic term completely, while seasonal differencing maintains seasonal correlation structures. The obtained results indicate that all three methods present acceptable performance overall. However, model accuracy in monthly streamflow prediction is higher with seasonal differencing than with the other two methods. Another advantage of seasonal differencing over the other methods is that the monthly streamflow is never estimated as negative. Standardization is the best method for predicting monthly water temperature although it is quite similar to seasonal differencing, while spectral analysis performed the weakest in all cases. It is concluded that for each monthly seasonal series, seasonal differencing is the best stationarization method in terms of periodic effect elimination. Moreover, the monthly water temperature is predicted with more accuracy than monthly streamflow. The criteria of the average stochastic term divided by the amplitude of the periodic term obtained for monthly streamflow and monthly water temperature were 0.19 and 0.30, 0.21 and 0.13, and 0.07 and 0.04 respectively. As a result, the periodic term is more dominant than the stochastic term for water temperature in the monthly water temperature series compared to streamflow series.

  12. Computation of symmetric, time-periodic solutions of the vortex sheet with surface tension

    PubMed Central

    Ambrose, David M.; Wilkening, Jon

    2010-01-01

    A numerical method is introduced for the computation of time-periodic vortex sheets with surface tension separating two immiscible, irrotational, two-dimensional ideal fluids of equal density. The approach is based on minimizing a nonlinear functional of the initial conditions and supposed period that is positive unless the solution is periodic, in which case it is zero. An adjoint-based optimal control technique is used to efficiently compute the gradient of this functional. Special care is required to handle singular integrals in the adjoint formulation. Starting with a solution of the linearized problem about the flat rest state, a family of smooth, symmetric breathers is found that, at quarter-period time intervals, alternately pass through a flat state of maximal kinetic energy, and a rest state in which all the energy is stored as potential energy in the interface. In some cases, the interface overturns before returning to the initial, flat configuration. It is found that the bifurcation diagram describing these solutions contains several disjoint curves separated by near-bifurcation events. PMID:20133691

  13. Spin-dependent tunneling time in periodic diluted-magnetic-semiconductor/nonmagnetic-barrier superlattices

    SciTech Connect

    Yang, Ping-Fan; Guo, Yong

    2016-02-01

    We investigate the tunneling time (dwell time) in periodic diluted-magnetic-semiconductor/nonmagnetic-barrier (DMS/NB) superlattices subjected to an external magnetic field. It is found that spin-dependent resonant bands form in the spectra of dwell time, which can be effectively manipulated by not only the external magnetic field but also the geometric parameters of the system. Moreover, an intuitive semiclassical delay is defined to illustrate the behavior of the dwell time, and the former one is shown to be the result of “smoothing out” the latter one. We also find that the dwell time in diluted-magnetic-semiconductor/semiconductor superlattices behaves surprisingly different from the DMS/NB case, especially for spin-down electrons.

  14. Tracing temperature in a nanometer size region in a picosecond time period

    PubMed Central

    Nakajima, Kaoru; Kitayama, Takumi; Hayashi, Hiroaki; Matsuda, Makoto; Sataka, Masao; Tsujimoto, Masahiko; Toulemonde, Marcel; Bouffard, Serge; Kimura, Kenji

    2015-01-01

    Irradiation of materials with either swift heavy ions or slow highly charged ions leads to ultrafast heating on a timescale of several picosecond in a region of several nanometer. This ultrafast local heating result in formation of nanostructures, which provide a number of potential applications in nanotechnologies. These nanostructures are believed to be formed when the local temperature rises beyond the melting or boiling point of the material. Conventional techniques, however, are not applicable to measure temperature in such a localized region in a short time period. Here, we propose a novel method for tracing temperature in a nanometer region in a picosecond time period by utilizing desorption of gold nanoparticles around the ion impact position. The feasibility is examined by comparing with the temperature evolution predicted by a theoretical model. PMID:26293488

  15. Tracing temperature in a nanometer size region in a picosecond time period.

    PubMed

    Nakajima, Kaoru; Kitayama, Takumi; Hayashi, Hiroaki; Matsuda, Makoto; Sataka, Masao; Tsujimoto, Masahiko; Toulemonde, Marcel; Bouffard, Serge; Kimura, Kenji

    2015-08-21

    Irradiation of materials with either swift heavy ions or slow highly charged ions leads to ultrafast heating on a timescale of several picosecond in a region of several nanometer. This ultrafast local heating result in formation of nanostructures, which provide a number of potential applications in nanotechnologies. These nanostructures are believed to be formed when the local temperature rises beyond the melting or boiling point of the material. Conventional techniques, however, are not applicable to measure temperature in such a localized region in a short time period. Here, we propose a novel method for tracing temperature in a nanometer region in a picosecond time period by utilizing desorption of gold nanoparticles around the ion impact position. The feasibility is examined by comparing with the temperature evolution predicted by a theoretical model.

  16. Time functions of deep earthquakes from broadband and short-period stacks

    USGS Publications Warehouse

    Houston, H.; Benz, H.M.; Vidale, J.E.

    1998-01-01

    To constrain dynamic source properties of deep earthquakes, we have systematically constructed broadband time functions of deep earthquakes by stacking and scaling teleseismic P waves from U.S. National Seismic Network, TERRAscope, and Berkeley Digital Seismic Network broadband stations. We examined 42 earthquakes with depths from 100 to 660 km that occurred between July 1, 1992 and July 31, 1995. To directly compare time functions, or to group them by size, depth, or region, it is essential to scale them to remove the effect of moment, which varies by more than 3 orders of magnitude for these events. For each event we also computed short-period stacks of P waves recorded by west coast regional arrays. The comparison of broadband with short-period stacks yields a considerable advantage, enabling more reliable measurement of event duration. A more accurate estimate of the duration better constrains the scaling procedure to remove the effect of moment, producing scaled time functions with both correct timing and amplitude. We find only subtle differences in the broadband time-function shape with moment, indicating successful scaling and minimal effects of attenuation at the periods considered here. The average shape of the envelopes of the short-period stacks is very similar to the average broadband time function. The main variations seen with depth are (1) a mild decrease in duration with increasing depth, (2) greater asymmetry in the time functions of intermediate events compared to deep ones, and (3) unexpected complexity and late moment release for events between 350 and 550 km, with seven of the eight events in that depth interval displaying markedly more complicated time functions with more moment release late in the rupture than most events above or below. The first two results are broadly consistent with our previous studies, while the third is reported here for the first time. The greater complexity between 350 and 550 km suggests greater heterogeneity in

  17. Assessment of the Main Natural Disturbances on Norwegian Forest Based on 20 Years of National Inventory

    PubMed Central

    Mola-Yudego, Blas; Eriksen, Rune; González-Olabarria, José Ramón

    2016-01-01

    The re-measurement of permanent forest inventories offers a unique opportunity to assess the occurrence and impact of forest disturbances. The present study aims at exploring the main forest damages in Norway based on the extensive data of several consecutive national forest inventories during the period 1995–2014. Five of the most common disturbance agents in Norway are selected for analysis: wind, snow, browsing, fungus and insect damage. The analyses focuses on the frequency and variation along time, the average damage at stand level and the spatial patterns of damage occurrence, resulting in a characterization of the damage produced by disturbances in Norway. The highest damage occurrences by disturbance agent are due to browsing, snow and wind. Snow presents a decreasing temporally trend in damage frequency in the studied period. By forest type, mature and intermediate birch forest are found to be more affected by snow damage, whereas mature spruce forest is by wind damage. The results from this study provide support to the hypothesis that damages by autumnal moth (Epirrita autumnata) on birch are more common in mature stands. No major attacks from bark beetle (Ips typographus) are found, probably related to the lack of major storm damages in the period. Forest types susceptibility to fungus has no apparent variation over time except in the last years, as increased occurrence is observed on mature spruce stands probably correlated with warmer than average periods. Browsing damage causes the most severe losses, as expected, in young stands, and is allocated mainly on the most productive forests. Although some of the disturbances present locally moderate effects, the results show no major disturbances threatening Norwegian forests in the studied period. Finally, the Norwegian national forest inventory demonstrates its reliability as a basis to understand the occurrence and effects of major natural disturbances. PMID:27570973

  18. Sobolev type equations of time-fractional order with periodical boundary conditions

    NASA Astrophysics Data System (ADS)

    Plekhanova, Marina

    2016-08-01

    The existence of a unique local solution for a class of time-fractional Sobolev type partial differential equations endowed by the Cauchy initial conditions and periodical with respect to every spatial variable boundary conditions on a parallelepiped is proved. General results are applied to study of the unique solvability for the initial boundary value problem to Benjamin-Bona-Mahony-Burgers and Allair partial differential equations.

  19. Periodic Time-Domain Nonlocal Nonreflecting Boundary Conditions for Duct Acoustics

    NASA Technical Reports Server (NTRS)

    Watson, Willie R.; Zorumski, William E.

    1996-01-01

    Periodic time-domain boundary conditions are formulated for direct numerical simulation of acoustic waves in ducts without flow. Well-developed frequency-domain boundary conditions are transformed into the time domain. The formulation is presented here in one space dimension and time; however, this formulation has an advantage in that its extension to variable-area, higher dimensional, and acoustically treated ducts is rigorous and straightforward. The boundary condition simulates a nonreflecting wave field in an infinite uniform duct and is implemented by impulse-response operators that are applied at the boundary of the computational domain. These operators are generated by convolution integrals of the corresponding frequency-domain operators. The acoustic solution is obtained by advancing the Euler equations to a periodic state with the MacCormack scheme. The MacCormack scheme utilizes the boundary condition to limit the computational space and preserve the radiation boundary condition. The success of the boundary condition is attributed to the fact that it is nonreflecting to periodic acoustic waves. In addition, transient waves can pass rapidly out of the solution domain. The boundary condition is tested for a pure tone and a multitone source in a linear setting. The effects of various initial conditions are assessed. Computational solutions with the boundary condition are consistent with the known solutions for nonreflecting wave fields in an infinite uniform duct.

  20. Thermal characteristics of time-periodic electroosmotic flow in a circular microchannel

    NASA Astrophysics Data System (ADS)

    Moghadam, Ali Jabari

    2015-10-01

    A theoretical analysis is performed to explore the thermal characteristics of electroosmotic flow in a circular microchannel under an alternating electric field. An analytical approach is presented to solve energy equation, and then, the exact solution of temperature profiles is obtained by using the Green's function method. This study reveals that the temperature field repeats itself for each half-period. Frequency has a strong influence on the thermal behavior of the flow field. For small values of the dimensionless frequency (small channel size, large kinematic viscosity, or small frequency), the advection mechanism is dominant in the whole domain and the resultant heating (Joule heating and wall heat flux) can be transferred by the complete flow field in the axial direction; while, the middle portion of the flow field at high dimensionless frequencies does not have sufficient time to transfer heat by advection, and the bulk fluid temperature, especially in heating, may consequently become greater than the wall temperature. In a particular instance of cooling mode, a constant surface temperature case is temporarily occurred in which the axial temperature gradient will be zero. For relatively high frequencies, the unsteady bulk fluid temperature in some radial positions at some moments may be equal to the wall temperature; hence instantaneous cylindrical surfaces with zero radial heat flux may occur over a period of time. Depending on the value and sign of the thermal scale ratio, the quasi-steady-state Nusselt number (time-averaged at one period) approaches a specific value as the electrokinetic radius becomes infinity.

  1. Time-varying singular value decomposition for periodic transient identification in bearing fault diagnosis

    NASA Astrophysics Data System (ADS)

    Zhang, Shangbin; Lu, Siliang; He, Qingbo; Kong, Fanrang

    2016-09-01

    For rotating machines, the defective faults of bearings generally are represented as periodic transient impulses in acquired signals. The extraction of transient features from signals has been a key issue for fault diagnosis. However, the background noise reduces identification performance of periodic faults in practice. This paper proposes a time-varying singular value decomposition (TSVD) method to enhance the identification of periodic faults. The proposed method is inspired by the sliding window method. By applying singular value decomposition (SVD) to the signal under a sliding window, we can obtain a time-varying singular value matrix (TSVM). Each column in the TSVM is occupied by the singular values of the corresponding sliding window, and each row represents the intrinsic structure of the raw signal, namely time-singular-value-sequence (TSVS). Theoretical and experimental analyses show that the frequency of TSVS is exactly twice that of the corresponding intrinsic structure. Moreover, the signal-to-noise ratio (SNR) of TSVS is improved significantly in comparison with the raw signal. The proposed method takes advantages of the TSVS in noise suppression and feature extraction to enhance fault frequency for diagnosis. The effectiveness of the TSVD is verified by means of simulation studies and applications to diagnosis of bearing faults. Results indicate that the proposed method is superior to traditional methods for bearing fault diagnosis.

  2. Enhancement in dentin collagen’s biological stability after proanthocyanidins treatment in clinically relevant time periods

    PubMed Central

    Liu, Yi; Chen, Mingsheng; Yao, Xiaomei; Xu, Changqi; Zhang, Ying; Wang, Yong

    2013-01-01

    Objective To investigate whether proanthocyanidins (PA) is capable of improving dentin collagen’s biological stability through cross-linking within time periods that are clinically relevant. Materials and methods Demineralized dentin collagen slabs were treated with 3.75 wt% PA solution for 10 s, 1 min, 30 min, 60 min, 120 min, 360 min, and 720 min, respectively. The resultant cross-linked collagen samples were subject to digestion with 0.1% collagenase at 37 °C for 2 h, 6 h, 12 h, 24 h, 36 h, and 48 h. The percentage of weight loss after digestion was calculated to evaluate PA-treated collagen’s resistance toward enzymatic degradation. Fourier-Transformed Infrared (FTIR) spectroscopy was used to probe evidences of PA-collagen interactions after various periods of PA treatment. Results The collagenase digestion assay suggests that PA treatment as short as 10 s can enhance collagen’s resistance toward enzymatic challenge. The FTIR spectroscopy further verifies that PA is indeed incorporated into collagen regardless of treatment time, possibly via a mechanism involving the chemical interactions between PA and collagen. Significance This study confirmed that PA can effectively cross-link collagen and improve its biological stability in time periods as short as 10 s. The use of PA as a priming agent is therefore clinically feasible and is a promising approach to improving the durability of current dentin bonding systems. PMID:23434233

  3. Real-time Periodic Processing of RT-middleware Utilizing Linux Standard Functionalities

    NASA Astrophysics Data System (ADS)

    Shimizu, Masaharu; Toda, Kengo; Hayashibara, Yasuo; Yamato, Hideaki; Furuta, Takayuki

    A new methodology of real-time periodic processing on RT-middleware based on the Linux standard functionalities is presented in this paper. The central of discussion is on the realization of real-time processing while keeping the reusability of software modules ensured by the RT-middleware framework as well as the portability provided by the Linux development mainstream. In order to show the validity of the proposed approach, two robot systems, including an omnidirectional electric wheelchair steered by haptic joystick, are presented and the discussion about the evaluation result follows from the view point of practicality.

  4. Delayed state feedback and chaos control for time-periodic systems via a symbolic approach

    NASA Astrophysics Data System (ADS)

    Ma, Haitao; Deshmukh, Venkatesh; Butcher, Eric; Averina, Victoria

    2005-08-01

    This paper presents a symbolic method for a delayed state feedback controller (DSFC) design for linear time-periodic delay (LTPD) systems that are open loop unstable and its extension to incorporate regulation and tracking of nonlinear time-periodic delay (NTPD) systems exhibiting chaos. By using shifted Chebyshev polynomials, the closed loop monodromy matrix of the LTPD system (or the linearized error dynamics of the NTPD system) is obtained symbolically in terms of controller parameters. The symbolic closed loop monodromy matrix, which is a finite dimensional approximation of an infinite dimensional operator, is used in conjunction with the Routh-Hurwitz criterion to design a DSFC to asymptotically stabilize the unstable dynamic system. Two controllers designs are presented. The first design is a constant gain DSFC and the second one is a periodic gain DSFC. The periodic gain DSFC has a larger region of stability in the parameter space than the constant gain DSFC. The asymptotic stability of the LTPD system obtained by the proposed method is illustrated by asymptotically stabilizing an open loop unstable delayed Mathieu equation. Control of a chaotic nonlinear system to any desired periodic orbit is achieved by rendering asymptotic stability to the error dynamics system. To accommodate large initial conditions, an open loop controller is also designed. This open loop controller is used first to control the error trajectories close to zero states and then the DSFC is switched on to achieve asymptotic stability of error states and consequently tracking of the original system states. The methodology is illustrated by two examples.

  5. Neural spike-timing patterns vary with sound shape and periodicity in three auditory cortical fields.

    PubMed

    Lee, Christopher M; Osman, Ahmad F; Volgushev, Maxim; Escabí, Monty A; Read, Heather L

    2016-04-01

    Mammals perceive a wide range of temporal cues in natural sounds, and the auditory cortex is essential for their detection and discrimination. The rat primary (A1), ventral (VAF), and caudal suprarhinal (cSRAF) auditory cortical fields have separate thalamocortical pathways that may support unique temporal cue sensitivities. To explore this, we record responses of single neurons in the three fields to variations in envelope shape and modulation frequency of periodic noise sequences. Spike rate, relative synchrony, and first-spike latency metrics have previously been used to quantify neural sensitivities to temporal sound cues; however, such metrics do not measure absolute spike timing of sustained responses to sound shape. To address this, in this study we quantify two forms of spike-timing precision, jitter, and reliability. In all three fields, we find that jitter decreases logarithmically with increase in the basis spline (B-spline) cutoff frequency used to shape the sound envelope. In contrast, reliability decreases logarithmically with increase in sound envelope modulation frequency. In A1, jitter and reliability vary independently, whereas in ventral cortical fields, jitter and reliability covary. Jitter time scales increase (A1 < VAF < cSRAF) and modulation frequency upper cutoffs decrease (A1 > VAF > cSRAF) with ventral progression from A1. These results suggest a transition from independent encoding of shape and periodicity sound cues on short time scales in A1 to a joint encoding of these same cues on longer time scales in ventral nonprimary cortices.

  6. Shifts in malaria vector species composition and transmission dynamics along the Kenyan coast over the past 20 years

    PubMed Central

    2013-01-01

    Background Over the past 20 years, numerous studies have investigated the ecology and behaviour of malaria vectors and Plasmodium falciparum malaria transmission on the coast of Kenya. Substantial progress has been made to control vector populations and reduce high malaria prevalence and severe disease. The goal of this paper was to examine trends over the past 20 years in Anopheles species composition, density, blood-feeding behaviour, and P. falciparum sporozoite transmission along the coast of Kenya. Methods Using data collected from 1990 to 2010, vector density, species composition, blood-feeding patterns, and malaria transmission intensity was examined along the Kenyan coast. Mosquitoes were identified to species, based on morphological characteristics and DNA extracted from Anopheles gambiae for amplification. Using negative binomial generalized estimating equations, mosquito abundance over the period were modelled while adjusting for season. A multiple logistic regression model was used to analyse the sporozoite rates. Results Results show that in some areas along the Kenyan coast, Anopheles arabiensis and Anopheles merus have replaced An. gambiae sensu stricto (s.s.) and Anopheles funestus as the major mosquito species. Further, there has been a shift from human to animal feeding for both An. gambiae sensu lato (s.l.) (99% to 16%) and An. funestus (100% to 3%), and P. falciparum sporozoite rates have significantly declined over the last 20 years, with the lowest sporozoite rates being observed in 2007 (0.19%) and 2008 (0.34%). There has been, on average, a significant reduction in the abundance of An. gambiae s.l. over the years (IRR = 0.94, 95% CI 0.90–0.98), with the density standing at low levels of an average 0.006 mosquitoes/house in the year 2010. Conclusion Reductions in the densities of the major malaria vectors and a shift from human to animal feeding have contributed to the decreased burden of malaria along the Kenyan coast. Vector species

  7. Exclusive Alternating Chemotherapy and Radiotherapy in Nonmetastatic Inflammatory Breast Cancer: 20 Years of Follow-Up

    SciTech Connect

    Bourgier, Celine; Pessoa, Eduardo Lima; Dunant, Ariane; Heymann, Steve; Spielmann, Marc; Uzan, Catherine; Mathieu, Marie-Christine; Arriagada, Rodrigo; Marsiglia, Hugo

    2012-02-01

    Background: Locoregional treatment of inflammatory breast cancer (IBC) is crucial because local relapses may be highly symptomatic and are commonly associated with distant metastasis. With a median follow-up of 20 years, we report here the long-term results of a monocentric clinical trial combining primary chemotherapy (CT) with a schedule of anthracycline-based CT and an alternating split-course of radiotherapy (RT Asterisk-Operator CT) without mastectomy. Methods and Materials: From September 1983 to December 1989, 124 women with nonmetastatic IBC (T4d M0) were treated with three cycles of primary AVCMF chemotherapy (anthracycline, vincristine, cyclophosphamide, methotrexate, and 5-fluorouracil) and then an alternating RT Asterisk-Operator CT schedule followed by three cycles of FAC. Hormonal therapy was systematically administered: ovarian irradiation (12 Gy in four fractions) or tamoxifen 20 mg daily. Results: Local control was achieved in 82% of patients. The 10- and 20-year local relapse rates were 26% and 33%, respectively, but only 10% of locally controlled cases were not associated with concurrent distant metastasis. The 10- and 20-year overall survival rates were 39% and 19%, respectively. Severe fibrosis occurred in 54% of patients, grade 3 brachial plexus neuropathy in 4%, grade 2 pneumonitis in 9%. Grade 1, 2 and 3 cardiac toxicity was observed in 3.8%, 3.8% and 1.2% of cases respectively. Conclusions: This combined regimen allowed good long-term local control without surgery. Survival rates were similar to those obtained with conventional regimens (primary chemotherapy, total mastectomy, and adjuvant radiotherapy). Since IBC continues to be an entity with a dismal prognosis, this approach, safely combining preoperative or postoperative radiation therapy and systemic treatments, should be reassessed when suitable targeted agents are available.

  8. Climate-change-related shifts in annual phenology of a temperate snake during the last 20 years

    NASA Astrophysics Data System (ADS)

    Rugiero, Lorenzo; Milana, Giuliano; Petrozzi, Fabio; Capula, Massimo; Luiselli, Luca

    2013-08-01

    Global warming is thought to be a far-reaching threat to biodiversity, and is supposed to influence several aspects of the ecology of animals. Global warming should influence especially the ectotherm vertebrates, which depend directly from the external thermal conditions for their activities and performances. Here, we analyze the changes in phenology which have occurred in the last 20 years in a marked population of vipers, Vipera aspis, and we try to relate these changes with the intervening climatic changes. We analyzed three metrics of viper's annual phenology: (i) annual onset of above-ground activity (hereby AOA); (ii) annual onset of feeding period (AOF); (iii) annual onset of the hibernation (AOH). The annual variations of these three phenological metrics were correlated to five variables of climatic data: (1) mean annual air temperature, (2) mean February air temperature, (3) mean July air temperature, (4) yearly number of rainy days, and (5) yearly number of days with rainstorm. We observed a statistically significant reduction of AOA values from >28 days between 1987 and 1997, to approximately 20 days from 1998 to 2011, with a similar statistical trend also found for AOF values. The number of days of delay in entering hibernation increased significantly since 1998. Three sets of relationships between climatic variables and metrics of viper phenology were statistically significant, i.e. the correlation (i) between annual mean temperature and AOA (negative), (ii) between annual mean temperature and AOF (negative), and (iii) between annual mean temperature and AOH (positive). The percent of field days (between 20th February and 20th March) with no viper observed also decreased significantly over the years. Our study showed that three different traits of the annual phenology of a Mediterranean snake are shifting in the 20+ years of monitoring, and that there is correlational evidence that these shifts are linked to intervening climate change.

  9. Scald management protocols - outcome differences in two different time periods using different treatment strategies

    PubMed Central

    Elmasry, M.; Steinvall, I.; Thorfinn, J.; Abbas, A.H..; Adly, O.A.; Abdelrahman, I.; Nagi, M.A.; Sjoberg, F.

    2016-01-01

    Summary Over the years the treatment of scalds in our centre has changed, moving more towards the use of biological dressings (xenografts). Management of scalds with mid dermal or deep dermal injuries differs among centers using different types of dressings, and recently biological membrane dressings were recommended for this type of injury. Here we describe differences in treatment outcome in different periods of time. All patients with scalds who presented to the Linkoping Burn Centre during two periods, early (1997-98) and later (2010-12) were included. Data were collected in the unit database and analyzed retrospectively. A lower proportion of autograft operations was found in the later period, falling from 32% to 19%. Hospital stay was shorter in the later period (3.5 days shorter, p=0.01) and adjusted duration of hospital stay/TBSA% was shorter (1.2 to 0.7, p=0.07). The two study groups were similar in most of the studied variables: we could not report any significant differences regarding outcome except for unadjusted duration of hospital stay. Further studies are required to investigate functional and aesthetic outcome differences between the treatment modalities. PMID:28149237

  10. Scald management protocols - outcome differences in two different time periods using different treatment strategies.

    PubMed

    Elmasry, M; Steinvall, I; Thorfinn, J; Abbas, A H; Adly, O A; Abdelrahman, I; Nagi, M A; Sjoberg, F

    2016-06-30

    Over the years the treatment of scalds in our centre has changed, moving more towards the use of biological dressings (xenografts). Management of scalds with mid dermal or deep dermal injuries differs among centers using different types of dressings, and recently biological membrane dressings were recommended for this type of injury. Here we describe differences in treatment outcome in different periods of time. All patients with scalds who presented to the Linkoping Burn Centre during two periods, early (1997-98) and later (2010-12) were included. Data were collected in the unit database and analyzed retrospectively. A lower proportion of autograft operations was found in the later period, falling from 32% to 19%. Hospital stay was shorter in the later period (3.5 days shorter, p=0.01) and adjusted duration of hospital stay/TBSA% was shorter (1.2 to 0.7, p=0.07). The two study groups were similar in most of the studied variables: we could not report any significant differences regarding outcome except for unadjusted duration of hospital stay. Further studies are required to investigate functional and aesthetic outcome differences between the treatment modalities.

  11. Finite-difference Time-domain Modeling of Laser-induced Periodic Surface Structures

    NASA Astrophysics Data System (ADS)

    Römer, G. R. B. E.; Skolski, J. Z. P.; Oboňa, J. Vincenc; Veld, A. J. Huis in't.

    Laser-induced periodic surface structures (LIPSSs) consist of regular wavy surface structures with amplitudes the (sub)micrometer range and periodicities in the (sub)wavelength range. It is thought that periodically modulated absorbed laser energy is initiating the growth of LIPSSs. The "Sipe theory" (or "Efficacy factor theory") provides an analytical model of the interaction of laser radiation with a rough surface of the material, predicting modulated absorption just below the surface of the material. To address some limitations of this model, the finite-difference time-domain (FDTD) method was employed to numerically solve the two coupled Maxwell's curl equations, for linear, isotropic, dispersive materials with no magnetic losses. It was found that the numerical model predicts the periodicity and orientation of various types of LIPSSs which might occur on the surface of the material sample. However, it should be noted that the numerical FDTD model predicts the signature or "fingerprints" of several types of LIPSSs, at different depths, based on the inhomogeneously absorbed laser energy at those depths. Whether these types of (combinations of) LIPSSs will actually form on a material will also depend on other physical phenomena, such as the excitation of the material, as well as thermal-mechanical phenomena, such as the state and transport of the material.

  12. Detection of faults in rotating machinery using periodic time-frequency sparsity

    NASA Astrophysics Data System (ADS)

    Ding, Yin; He, Wangpeng; Chen, Binqiang; Zi, Yanyang; Selesnick, Ivan W.

    2016-11-01

    This paper addresses the problem of extracting periodic oscillatory features in vibration signals for detecting faults in rotating machinery. To extract the feature, we propose an approach in the short-time Fourier transform (STFT) domain where the periodic oscillatory feature manifests itself as a relatively sparse grid. To estimate the sparse grid, we formulate an optimization problem using customized binary weights in the regularizer, where the weights are formulated to promote periodicity. In order to solve the proposed optimization problem, we develop an algorithm called augmented Lagrangian majorization-minimization algorithm, which combines the split augmented Lagrangian shrinkage algorithm (SALSA) with majorization-minimization (MM), and is guaranteed to converge for both convex and non-convex formulation. As examples, the proposed approach is applied to simulated data, and used as a tool for diagnosing faults in bearings and gearboxes for real data, and compared to some state-of-the-art methods. The results show that the proposed approach can effectively detect and extract the periodical oscillatory features.

  13. Transfer-matrix approach for finite-difference time-domain simulation of periodic structures.

    PubMed

    Deinega, Alexei; Belousov, Sergei; Valuev, Ilya

    2013-11-01

    Optical properties of periodic structures can be calculated using the transfer-matrix approach, which establishes a relation between amplitudes of the wave incident on a structure with transmitted or reflected waves. The transfer matrix can be used to obtain transmittance and reflectance spectra of finite periodic structures as well as eigenmodes of infinite structures. Traditionally, calculation of the transfer matrix is performed in the frequency domain and involves linear algebra. In this work, we present a technique for calculation of the transfer matrix using the finite-difference time-domain (FDTD) method and show the way of its implementation in FDTD code. To illustrate the performance of our technique we calculate the transmittance spectra for opal photonic crystal slabs consisting of multiple layers of spherical scatterers. Our technique can be used for photonic band structure calculations. It can also be combined with existing FDTD methods for the analysis of periodic structures at an oblique incidence, as well as for modeling point sources in a periodic environment.

  14. Transfer-matrix approach for finite-difference time-domain simulation of periodic structures

    NASA Astrophysics Data System (ADS)

    Deinega, Alexei; Belousov, Sergei; Valuev, Ilya

    2013-11-01

    Optical properties of periodic structures can be calculated using the transfer-matrix approach, which establishes a relation between amplitudes of the wave incident on a structure with transmitted or reflected waves. The transfer matrix can be used to obtain transmittance and reflectance spectra of finite periodic structures as well as eigenmodes of infinite structures. Traditionally, calculation of the transfer matrix is performed in the frequency domain and involves linear algebra. In this work, we present a technique for calculation of the transfer matrix using the finite-difference time-domain (FDTD) method and show the way of its implementation in FDTD code. To illustrate the performance of our technique we calculate the transmittance spectra for opal photonic crystal slabs consisting of multiple layers of spherical scatterers. Our technique can be used for photonic band structure calculations. It can also be combined with existing FDTD methods for the analysis of periodic structures at an oblique incidence, as well as for modeling point sources in a periodic environment.

  15. Timing Studies of X Persei and the Discovery of Its Transient Quasi-periodic Oscillation Feature

    NASA Technical Reports Server (NTRS)

    Acuner, Z.; Inam,S. C.; Sahiner, S.; Serim, M. M.; Baykal, A.; Swank, J.

    2014-01-01

    We present a timing analysis of X Persei (X Per) using observations made between 1998 and 2010 with the Proportional Counter Array (PCA) onboard the Rossi X-ray Timing Explorer (RXTE) and with the INTEGRAL Soft Gamma-Ray Imager (ISGRI). All pulse arrival times obtained from the RXTE-PCA observations are phase-connected and a timing solution is obtained using these arrival times. We update the long-term pulse frequency history of the source by measuring its pulse frequencies using RXTE-PCA and ISGRI data. From the RXTEPCA data, the relation between the frequency derivative and X-ray flux suggests accretion via the companion's stellar wind. However, the detection of a transient quasi-periodic oscillation feature, peaking at approximately 0.2 Hz, suggests the existence of an accretion disc. We find that doublebreak models fit the average power spectra well, which suggests that the source has at least two different accretion flow components dominating the overall flow. From the power spectrum of frequency derivatives, we measure a power-law index of approximately - 1, which implies that, on short time-scales, disc accretion dominates over noise, while on time-scales longer than the viscous time-scales, the noise dominates. From pulse profiles, we find a correlation between the pulse fraction and the count rate of the source.

  16. Water Erosion in Relation with Soil Management System and Crop Sequence during 20 Years on an Inceptisol in South Brazil

    NASA Astrophysics Data System (ADS)

    Bertol, I.; Schick, J.; Barbosa, F. T.; Paz-Ferreiro, J.; Flores, M. T.; Paz González, A.

    2012-04-01

    Soil erosion still remains persistent at the world scale, even if big efforts have been done to control and reduce it, mainly using soil crop residues to protect soil surface. Although in South Brazil the main management system for most crops is no tillage and direct drilling, water erosion prevails as the most important soil erosion type, which is due both, to the high erosivity and the evenly distribution of rainfall over the year. Moreover, some crops are still grown under soil tillage systems consisting of ploughing, harrowing and less frequently chiselling. Starting 1992, a field experiment under natural rainfall has been conducted on an Inceptisol located in Lages, Santa Catarina State, Brazil, which objective was to assess rainfall water erosion. Two soil cover conditions and four soil management systems were studied: I) a crop rotation, which included oats (Avena strigosa), soybean (Glycine max), common vetch (Vicia sativa), maize (Zea mays), fodder radish (Raphanus sativus) and common bean (Phaseolus vulgaris) under the following soil management types: 1) ploughing plus two levelling operations (CT), chiselling plus levelling (RT) and direct drilling with no tillage (NT), and II) bare soil (BS) without crop cover tilled by ploughing plus two levelling. In more than 90% of the study cases, soil losses were collected for single rain events with erosive power, whose erosivity was calculated. Total rain recorded during the 20 year experimental period was approximately 66,400 mm, which is equivalent to roughly 105,700, MJ mm ha-1 h-1 (EI30), whereas soil losses in the BS treatment were higher than 1,700 t.ha-1. On average, soil losses under RT treatment showed a 92% reduction in relation with BS, whereas under CT the reduction in relation to BS was about 66%. Soil management by direct drilling (NT) was the most efficient system to minimize water erosion, as soil losses decreased about 98% when compared with BS. Moreover, soil management systems with a crop

  17. Practitioners' Perceptions of the Soccer Extra-Time Period: Implications for Future Research

    PubMed Central

    Harper, Liam D.; Fothergill, Melissa; West, Daniel J.; Stevenson, Emma; Russell, Mark

    2016-01-01

    Qualitative research investigating soccer practitioners’ perceptions can allow researchers to create practical research investigations. The extra-time period of soccer is understudied compared to other areas of soccer research. Using an open-ended online survey containing eleven main and nine sub questions, we gathered the perceptions of extra-time from 46 soccer practitioners, all working for different professional soccer clubs. Questions related to current practices, views on extra-time regulations, and ideas for future research. Using inductive content analysis, the following general dimensions were identified: ‘importance of extra-time’, ‘rule changes’, ‘efficacy of extra-time hydro-nutritional provision’, ‘nutritional timing’, ‘future research directions’, ‘preparatory modulations’ and ‘recovery’. The majority of practitioners (63%) either agreed or strongly agreed that extra-time is an important period for determining success in knockout football match-play. When asked if a fourth substitution should be permitted in extra-time, 67% agreed. The use of hydro-nutritional strategies prior to extra-time was predominately considered important or very important. However; only 41% of practitioners felt that it was the most important time point for the use of nutritional products. A similar number of practitioners account (50%) and do not (50%) account for the potential of extra-time when training and preparing players and 89% of practitioners stated that extra-time influences recovery practices following matches. In the five minute break prior to extra-time, the following practices (in order of priority) were advocated to players: hydration, energy provision, massage, and tactical preparations. Additionally, 87% of practitioners advocate a particular nutritional supplementation strategy prior to extra-time. In order of importance, practitioners see the following as future research areas: nutritional interventions, fatigue responses

  18. Dyscirculatory encephalopathy in Chernobyl disaster clean-up workers (a 20-year study).

    PubMed

    Podsonnaya, I V; Shumakher, G I; Golovin, V A

    2010-05-01

    Results obtained over 20-years of following 536 Chernobyl clean-up workers and 436 control subjects are presented. Dyscirculatory encephalopathy developed more frequently in persons exposed to radiation at age 30 years. As compared with the control group, workers were characterized by early onset of disease, faster progression, stable symptomatology for 5-6 years, and further progression of disease in the form of autonomic dysfunction, psycho-organic syndrome, and epilepsy. Major strokes were also more common in clean-up workers.

  19. A 20-Year Study of Undergraduate Astronomy Students' Beliefs and Knowledge in Science and Technology

    NASA Astrophysics Data System (ADS)

    Buxner, S. R.; Antonellis, J.; Impey, C. D.

    2011-09-01

    This poster presents data from a 20-year study into the science literacy of undergraduates enrolled in introductory astronomy courses. Responses from almost 10,000 undergraduate students from 1989 to 2009 have been analyzed. We present students' responses to both science literacy and belief questions by year and demographic variables, as well as trends in open-ended responses. Analysis revealed that demographic variables accounted for only 7% of the variance in students' science literacy scores. The strongest predictor of a student's overall science literacy score was how many science courses they had completed, yet this only accounted for 4% of the variance, as did students' beliefs regarding science and technology issues.

  20. Primary Hyperparathyroidism with Extensive Brown Tumors and Multiple Fractures in a 20-Year-Old Woman

    PubMed Central

    Choi, Ju Hee; Kim, Kyoung Jin; Lee, Ye Jin; Kim, Sun Hwa; Kim, Sin Gon; Jung, Kwang Yoon; Choi, Dong Seop

    2015-01-01

    A brown tumor is a benign fibrotic, erosive bony lesion caused by localized, rapid osteoclastic turnover, resulting from hyperparathyroidism. Although brown tumors are one of the most pathognomonic signs of primary hyperparathyroidism, they are rarely seen in clinical practice. In this report, we present a case of 20-year-old woman with recurrent fractures and bone pain. Plain digital radiographs of the affected bones revealed multiple erosive bone tumors, which were finally diagnosed as brown tumors associated with primary hyperparathyroidism due to a parathyroid adenoma. This case shows that multiple, and clinically severe form of brown tumors can even occur in young patients. PMID:26354493

  1. Kawasaki Disease in India, Lessons Learnt Over the Last 20 Years.

    PubMed

    Singh, Surjit; Kawasaki, Tomisaku

    2016-02-01

    Over the last 20 years, Kawasaki disease is being increasingly recognized in India and it may soon replace acute rheumatic fever to become the commonest cause of acquired heart disease amongst children. However, the vast majority of children with Kawasaki disease in India are still not being diagnosed. Diagnosis of Kawasaki disease is based on a constellation of clinical findings which have a typical temporal sequence. All pediatricians must we familiar with the nuances involved in arriving at a diagnosis of Kawasaki disease. With early diagnosis and prompt treatment, the risk of coronary artery abnormalities can be significantly reduced.

  2. History of Division 29, 1993-2013: another 20 years of psychotherapy.

    PubMed

    Williams, Elizabeth Nutt; Barnett, Jeffrey E; Canter, Mathilda B

    2013-03-01

    The history of Division 29 (Psychotherapy) of the American Psychological Association (APA) from 1993 to 2013 is reviewed. The 20 years of history can be traced via the Division's primary publications (the journal Psychotherapy and its newsletter Psychotherapy Bulletin) as well as the history of those who have served leadership roles in the Division and have won Divisional awards. Several recurring themes emerge related to the Division's articulations of its own identity, the Division's advocacy efforts vis-à-vis the profession and the APA, and the work of the Division on behalf of major social issues (such as disaster relief and the nation's health care).

  3. Asynchronous Periodic Edge-Event Triggered Control for Double-Integrator Networks With Communication Time Delays.

    PubMed

    Duan, Gaopeng; Xiao, Feng; Wang, Long

    2017-01-23

    This paper focuses on the average consensus of double-integrator networked systems based on the asynchronous periodic edge-event triggered control. The asynchronous property lies in the edge event-detecting procedure. For different edges, their event detections are performed at different times and the corresponding events occur independently of each other. When an event is activated, the two adjacent agents connected by the corresponding link sample their relative state information and update their controllers. The application of incidence matrix facilitates the transformation of control objects from the agent-based to the edge-based. Practically, due to the constraints of network bandwidth and communication distance, agents usually cannot receive the instantaneous information of some others, which has an impact on the system performance. Hence, it is necessary to investigate the presence of communication time delays. For double-integrator multiagent systems with and without communication time delays, the average state consensus can be asynchronously achieved by designing appropriate parameters under the proposed event-detecting rules. The presented results specify the relationship among the maximum allowable time delays, interaction topologies, and event-detecting periods. Furthermore, the proposed protocols have the advantages of reduced communication costs and controller-updating costs. Simulation examples are given to illustrate the proposed theoretical results.

  4. Landsat: Planning the Next 20 Years of Earth Observation and Science

    NASA Astrophysics Data System (ADS)

    Ryker, S. J.; Larsen, M. C.; Newman, T. R.

    2013-12-01

    The Landsat series of Earth-observing satellites began 41 years ago as a partnership between the U.S. Department of the Interior (DOI) and NASA. The U.S. Geological Survey (USGS), as DOI's Earth science agency, provides Landsat's ground systems and data and develops value-added science products and applications. In 2013 the Administration committed to continue the Landsat program for the long term, and directed NASA and USGS to develop a series of spaceborne systems to provide global, continuous Landsat-quality multispectral and thermal infrared measurements for at least 20 years beyond Landsat 9. The Administration also directed the USGS to develop the program's long-term science directions, with special emphasis on making Landsat data more easily used in a wide variety of disciplines and fields of practice. With Landsats 7 and 8 on orbit, the USGS provides data every eight days for any location on the Earth's land masses. Given eight-day data collection and Landsat's 41-year historical archive, researchers and decision-makers can assess phenomena occurring at weekly to decadal time scales. With this in mind, the USGS has identified a set of Landsat-based science products that will improve applications used by natural resource managers and will contribute to the international and interagency climate monitoring community's initiative to develop consistent climate data records (CDRs) and essential climate variables (ECVs). Key Landsat-derived CDRs include surface reflectance and surface temperature, and ECV products will include measures of fire disturbance, snow covered area, surface water extent, land cover, and above-ground green biomass. These interpretive products will provide an authoritative basis for regional to continental scale identification of historical change, monitoring of current conditions, and predicting future conditions. The Administration has also assigned USGS the responsibility to analyze Landsat users' needs to inform future operational

  5. Performance of ROB's near real-time ionospheric product during normal and disturbed space weather periods.

    NASA Astrophysics Data System (ADS)

    Bergeot, Nicolas; Chevalier, Jean-Marie; Bruyninx, Carine

    2015-04-01

    Several agencies are routinely monitoring the vertical Total Electron Content (vTEC) using GNSS data. Derived maps are available with different latencies, area extents, and grid/time resolutions. However, no high-resolution maps are publically available over Europe in near real-time. In this frame, the Royal Observatory of Belgium (ROB) developed the ROB-IONO software which takes advantage of the dense EUREF Permanent GNSS Network (EPN) to monitor the ionosphere. The main ROB products consist of ionospheric vTEC maps over Europe and their variability estimated in near real-time every 15 min on 0.5° x 0.5° grids using GPS observations. The maps are available online with a latency of ~3 min in the IONEX format at ftp://gnss.oma.be and as interactive web pages at www.gnss.be. During normal ionospheric activity, the ROB-TEC maps show a good agreement with widely used post-processed global products from IGS, CODE and ESA, with mean differences of 1.3 ± 0.9, 0.6 ± 0.7 and 0.4 ± 1.6 TECu respectively for the period 2012 to mid-2013. For a disturbed period, such as the 2003 Halloween ionospheric storm, the mean differences with IGS, CODE and ESA maps are respectively 0.9 ± 2.2, 0.1 ± 2.0 and 0.6 ± 6.8 TECu, with maximum differences (>38 TECu) occurring during the major phase of the storm. These differences are due to the lower resolution of global products in time and space compared to the ROB-TEC maps. A description of two recent events, on March 17, 2013 and February 27, 2014 highlights the capability of the method adopted to detect in near real-time abnormal ionospheric behaviour over Europe. The potential of the variability maps as an indicator of rapid ionospheric variations during the 15 min of observations is also highlighted. More than 30 ionospheric events associated with Space weather were detected during the period 2012-2014. The ionospheric perturbations are associated with Coronal Mass Ejections (CMEs, ~70% of the time), active geomagnetic conditions

  6. Prefrontal activity during response inhibition decreases over time in the postpartum period.

    PubMed

    Bannbers, Elin; Gingnell, Malin; Engman, Jonas; Morell, Arvid; Sylvén, Sara; Skalkidou, Alkistis; Kask, Kristiina; Bäckström, Torbjörn; Wikström, Johan; Poromaa, Inger Sundström

    2013-03-15

    The postpartum period is characterized by complex hormonal changes, but human imaging studies in the postpartum period have thus far predominantly focused on the neural correlates of maternal behavior or postpartum depression, whereas longitudinal studies on neural correlates of cognitive function across the postpartum period in healthy women are lacking. The aim of this study was to longitudinally examine response inhibition, as a measure of executive function, during the postpartum period and its neural correlates in healthy postpartum women and non-postpartum controls. Thirteen healthy postpartum women underwent event-related functional magnetic resonance imaging while performing a Go/NoGo task. The first assessment was made within 48 h of delivery, and the second at 4-7 weeks postpartum. In addition, 13 healthy women examined twice during the menstrual cycle were included as non-postpartum controls. In postpartum women region of interest analyses revealed task-related decreased activations in the right inferior frontal gyrus, right anterior cingulate, and bilateral precentral gyri at the late postpartum assessment. Generally, postpartum women displayed lower activity during response inhibition in the bilateral inferior frontal gyri and precentral gyri compared to non-postpartum controls. No differences in performance on the Go/NoGo task were found between time-points or between groups. In conclusion, this study has discovered that brain activity in prefrontal areas during a response inhibition task decreases throughout the course of the first postpartum weeks and is lower than in non-postpartum controls. Further studies on the normal adaptive brain activity changes that occur during the postpartum period are warranted.

  7. Evaluation of indoor air composition time variation in air-tight occupied spaces during night periods

    NASA Astrophysics Data System (ADS)

    Markov, Detelin

    2012-11-01

    This paper presents an easy-to-understand procedure for prediction of indoor air composition time variation in air-tight occupied spaces during the night periods. The mathematical model is based on the assumptions for homogeneity and perfect mixing of the indoor air, the ideal gas model for non-reacting gas mixtures, mass conservation equations for the entire system and for each species, a model for prediction of basal metabolic rate of humans as well as a model for prediction of O2 consumption rate and both CO2 and H2O generation rates by breathing. Time variation of indoor air composition is predicted at constant indoor air temperature for three scenarios based on the analytical solution of the mathematical model. The results achieved reveal both the most probable scenario for indoor air time variation in air-tight occupied spaces as well as the cause for morning tiredness after having a sleep in a modern energy efficient space.

  8. Ultrafast time dynamics studies of periodic lattices with free electron laser radiation

    SciTech Connect

    Quevedo, W.; Busse, G.; Hallmann, J.; More, R.; Petri, M.; Rajkovic, I.; Krasniqi, F.; Rudenko, A.; Tschentscher, T.; Stojanovic, N.; Duesterer, S.; Treusch, R.; Tolkiehn, M.; Techert, S.

    2012-11-01

    It has been proposed that radiation from free electron laser (FEL) at Hamburg (FLASH) can be used for ultrafast time-resolved x-ray diffraction experiments based on the near-infrared (NIR) pump/FEL probe scheme. Here, investigation probing the ultrafast structural dynamics of periodic nano-crystalline organic matter (silver behenate) with such a scheme is reported. Excitation with a femtosecond NIR laser leads to an ultrafast lattice modification which time evolution has been studied through the scattering of vacuum ultraviolet FEL pulses. The found effect last for 6 ps and underpins the possibility for studying nanoperiodic dynamics down to the FEL source time resolution. Furthermore, the possibility of extending the use of silver behenate (AgBh) as a wavelength and temporal calibration tool for experiments with soft x-ray/FEL sources is suggested.

  9. Master equation approach to time-dependent escape rate over a periodically oscillating barrier.

    PubMed

    Wang, Xin-Xin; Bao, Jing-Dong

    2011-01-01

    We propose a master equation approach to investigate the transition function and the escape dynamics of a general damping particle in a metastable potential. The transition function in the master equation is obtained analytically from the Langevin dynamics. We apply it to the oscillating barrier problem, in which the potential is structured by a harmonic potential smoothly linking with an inverse harmonic one, and thus both the barrier height and the curvature of potential change periodically with time. We use a Monte Carlo method to simulate the master equation and then calculate a time-dependent escape rate. This can decrease the coarse grain and save more computing time in comparison with the Langevin simulation. Our result has shown that there is a resonant activation phenomenon for the escape rate in the underdamped case.

  10. Developmental histories of perceived racial discrimination and diurnal cortisol profiles in adulthood: A 20-year prospective study

    PubMed Central

    Adam, Emma K.; Heissel, Jennifer A.; Zeiders, Katharine H.; Richeson, Jennifer A.; Ross, Emily C.; Ehrlich, Katherine B.; Levy, Dorainne J.; Kemeny, Margaret; Brodish, Amanda B.; Malanchuk, Oksana; Peck, Stephen C.; Fuller-Rowell, Thomas E.; Eccles, Jacquelynne S.

    2015-01-01

    Perceived racial discrimination (PRD) has been associated with altered diurnal cortisol rhythms in past cross-sectional research. We investigate whether developmental histories of PRD, assessed prospectively, are associated with adult diurnal cortisol profiles. One-hundred and twelve (N = 50 Black, N = 62 White) adults from the Maryland Adolescent Development in Context Study provided saliva samples in adulthood (at approximately age 32 years) at waking, 30 min after waking, and at bedtime for 7 days. Diurnal cortisol measures were calculated, including waking cortisol levels, diurnal cortisol slopes, the cortisol awakening response (CAR), and average daily cortisol (AUC). These cortisol outcomes were predicted from measures of PRD obtained over a 20-year period beginning when individuals were in 7th grade (approximately age 12). Greater average PRD measured across the 20-year period predicted flatter adult diurnal cortisol slopes for both Black and White adults, and a lower CAR. Greater average PRD also predicted lower waking cortisol for Black, but not White adults. PRD experiences in adolescence accounted for many of these effects. When adolescent and young adult PRD are entered together predicting cortisol outcomes, PRD experiences in adolescence (but not young adulthood) significantly predicted flatter diurnal cortisol slopes for both Black and White adults. Adolescent, but not young adult PRD, also significantly predicted lower waking and lower average cortisol for Black adults. Young adult PRD was, however, a stronger predictor of the CAR, predicting a marginally lower CAR for Whites, and a significantly larger CAR for Blacks. Effects were robust to controlling for covariates including health behaviors, depression, income and parent education levels. PRD experiences interacted with parent education and income to predict aspects of the diurnal cortisol rhythm. Although these results suggest PRD influences on cortisol for both Blacks and Whites, the key

  11. Enrichment of natural (15)N abundance during soil N losses under 20years of continuous cereal cropping.

    PubMed

    Jones, Andrew R; Dalal, Ram C

    2017-01-01

    It is generally accepted that the enrichment of natural (15)N abundance in soil over time is reflective of historic N cycling and loss, but this process in cropping soils is not yet clear. In this study, we identified an enrichment gradient of natural (15)N abundance during 20-year chronosequence of cereal cropping on Alfisols in southwest Queensland, Australia, that have no history of fertilisation. We demonstrate that the increase in soil (15)N abundance is explained by isotopic fractionation of (15)N during organic N mineralisation and nitrification, which lead to isotopically heavier ammonium retained in the soil and isotopically lighter soil nitrate taken up and removed by seasonal crops during harvest. Here we present a framework for natural (15)N isotopic fractionation co-occurring with N losses during long-term cultivation.

  12. Changes in orthodontic treatment modalities in the past 20 years: exploring the link between technology and scientific evidence.

    PubMed

    Bradley, T Gerard

    2013-01-01

    STATEMENT OF THE ISSUE: Is there a link between the many perceived advances in orthodontic techniques/therapy and science in the past 20 years? The purpose of this paper is to take five topics and match the perceptions with the scientific evidence. The variety of appliances and the swings in treatment philosophy have been dramatic, including the swing from extraction to non-extraction therapy, the introduction of space-age wires, appliances that grow mandibles, the introduction and extraordinary growth of Invisalign, and reduced friction brackets to reduce treatment time, all with claims by manufacturers of better results than ever before. The focus is on faster treatment, reduced visits/appointments and superior results. Most of these 'advancements' represent what has been the 'juggernaut of technology'. Five questions are posed, and an evidence-based approach is used to critically examine the literature in these selected topics.

  13. A 20-year data set of surface longwave fluxes in the Arctic

    SciTech Connect

    Jennifer Francis

    2004-06-15

    Creation of 20-year data set of surface infrared fluxes from satellite measurements. A reliable estimate of the surface downwelling longwave radiation flux (DLF) is a glaring void in available forcing data sets for models of Arctic sea ice and ocean circulation. We have developed a new method to estimate the DLF from a combination of satellite sounder retrievals and brightness temperatures from the TIROS Operational Vertical Sounder (TOVS), which has flown on NOAA polar-orbiting satellites continuously since late 1979. The overarching goal of this project was to generate a 20-year data set of surface downwelling longwave flux measurements from TOVS data over the Arctic Ocean. Daily gridded fields of DLF were produced with a spatial resolution of (100 km){sup 2} north of 60{sup o}N for 22.5 years rather than only 20. Surface measurements from the field station at Barrow, AK--part of the Atmospheric Radiation Measurement (ARM) Program --and from the Surface Heat Budget of the Arctic (SHEBA) were used to validate the satellite-derived fluxes and develop algorithm improvements for conditions that had resulted in systematic errors in early versions of the algorithm. The resulting data set has already been sent to two other investigators for incorporation into their research, and we will soon complete preparations to send the products to the National Snow and Ice Data Center and ARM data archive, where it can be disseminated to the scientific community.

  14. Arsenic in atmospheric deposition at the Czech-Polish border: two sampling campaigns 20 years apart.

    PubMed

    Dousová, Barbora; Erbanová, Lucie; Novák, Martin

    2007-11-15

    Arsenic (As) occurs in atmospheric deposition both in soluble and insoluble forms, mainly bound to fine aerosol particles (less than 2.5 microm). Interception deposition (i.e. fog, dew and ice accretion) represents a specific type of atmospheric deposition, which has been much more contaminated with As than bulk deposition. This study compares the As amount and its binding forms in bulk and interception deposition in the winters of 1984-1986 and 2003-2005 in the Orlické hory mountains (Adlergebirge) near the Czech-Polish border; sampled and analysed by the same methodology. The As concentrations in ice accretions decreased 16 times over the twenty year period (from 50 microg L(-1) to 3 microg L(-1)), while the pH values increased by 0.8 units. As concentrations in snow decreased from 15 microg L(-1) in 1984-1986 to <2 microg L(-1) in 2003-2005. This decline mirrored the considerable decrease in industrial emissions in Central Europe. Higher acidity of interception deposition (about 1 pH unit) in comparison with the bulk deposition was observed in both sampling periods. The quantity of bulk deposition (snowfall) also influenced the As concentration in interception deposition. Dry periods resulted in higher As-amounts in interception deposition due to limited washing of atmospheric aerosol particles by wet deposition. The As concentration and stability in atmospheric deposition are important for the study of subsequent As-migration and/or accumulation in soil -- groundwater -- surface water.

  15. Dynamical systems analysis of fluid transport in time-periodic vortex ring flows

    NASA Astrophysics Data System (ADS)

    Shariff, Karim; Leonard, Anthony; Ferziger, Joel H.

    2006-04-01

    It is known that the stable and unstable manifolds of dynamical systems theory provide a powerful tool for understanding Lagrangian aspects of time-periodic flows. In this work we consider two time-periodic vortex ring flows. The first is a vortex ring with an elliptical core. The manifolds provide information about entrainment and detrainment of irrotational fluid into and out of the volume transported with the ring. The likeness of the manifolds with features observed in flow visualization experiments of turbulent vortex rings suggests that a similar process might be at play. However, what precise modes of unsteadiness are responsible for stirring in a turbulent vortex ring is left as an open question. The second situation is that of two leapfrogging rings. The unstable manifold shows striking agreement with even the fine features of smoke visualization photographs, suggesting that fluid elements in the vicinity of the manifold are drawn out along it and begin to reveal its structure. We suggest that interpretations of these photographs that argue for complex vorticity dynamics ought to be reconsidered. Recently, theoretical and computational tools have been developed to locate structures analogous to stable and unstable manifolds in aperiodic, or finite-time systems. The usefulness of these analogs is demonstrated, using vortex ring flows as an example, in the paper by Shadden, Dabiri, and Marsden [Phys. Fluids 18, 047105 (2006)].

  16. Time-Periodic Solutions of Driven-Damped Trimer Granular Crystals

    DOE PAGES

    Charalampidis, E. G.; Li, F.; Chong, C.; ...

    2015-01-01

    We consider time-periodic structures of granular crystals consisting of alternate chrome steel (S) and tungsten carbide (W) spherical particles where each unit cell follows the pattern of a 2 : 1 trimer: S-W-S. The configuration at the left boundary is driven by a harmonic in-time actuation with given amplitude and frequency while the right one is a fixed wall. Similar to the case of a dimer chain, the combination of dissipation, driving of the boundary, and intrinsic nonlinearity leads to complex dynamics. For fixed driving frequencies in each of the spectral gaps, we find that the nonlinear surface modes and the statesmore » dictated by the linear drive collide in a saddle-node bifurcation as the driving amplitude is increased, beyond which the dynamics of the system becomes chaotic. While the bifurcation structure is similar for solutions within the first and second gap, those in the first gap appear to be less robust. We also conduct a continuation in driving frequency, where it is apparent that the nonlinearity of the system results in a complex bifurcation diagram, involving an intricate set of loops of branches, especially within the spectral gap. The theoretical findings are qualitatively corroborated by the experimental full-field visualization of the time-periodic structures.« less

  17. The Cluster Science Archive: from Time Period to Physics Based Search

    NASA Astrophysics Data System (ADS)

    Masson, A.; Escoubet, C. P.; Laakso, H. E.; Perry, C. H.

    2015-12-01

    Since 2000, the Cluster spacecraft relay the most detailed information on how the solar wind affects our geospace in three dimensions. Science output from Cluster is a leap forward in our knowledge of space plasma physics: the science behind space weather. It has been key in improving the modeling of the magnetosphere and understanding its various physical processes. Cluster data have enabled the publication of more than 2000 refereed papers and counting. This substantial scientific return is often attributed to the online availability of the Cluster data archive, now called the Cluster Science Archive (CSA). It is being developed by the ESAC Science Data Center (ESDC) team and maintained alongside other science ESA archives at ESAC (ESA Space Astronomy Center, Madrid, Spain). CSA is a public archive, which contains the entire set of Cluster high-resolution data, and other related products in a standard format and with a complete set of metadata. Since May 2015, it also contains data from the CNSA/ESA Double Star mission (2003-2008), a mission operated in conjunction with Cluster. The total amount of data format now exceeds 100 TB. Accessing CSA requires to be registered to enable user profiles and CSA accounts more than 1,500 users. CSA provides unique tools for visualizing its data including - on-demand particle distribution functions visualization - fast data browsing with more than 15TB of pre-generated plots - inventory plots It also offers command line capabilities (e.g. data access via Matlab or IDL softwares, data streaming). Despite its reliability, users can only request data for a specific time period while scientists often focus on specific regions or data signatures. For these reasons, a data-mining tool is being developed to do just that. It offers an interface to select data based not only on a time period but on various criteria including: key physical parameters, regions of space and spacecraft constellation geometry. The output of this tool is a

  18. The method of calculating forced oscillations in nonlinear discrete-time systems under periodic external actions

    NASA Astrophysics Data System (ADS)

    Bryuhanov, Yu. A.

    2010-08-01

    We consider a method for calculating forced oscillations in nonlinear discrete-time systems under periodic external actions. The method is based on representing the stationary oscillations in the form of an invariant set of nonlinear discrete point mappings and allows one to calculate the nonlinear-system response in the steady-state regime. The examples of using this method for calculating forced oscillations in the first- and second-order nonlinear recursive systems under the harmonic-signal action on such systems are presented.

  19. Geometric tools for solving the FDI problem for linear periodic discrete-time systems

    NASA Astrophysics Data System (ADS)

    Longhi, Sauro; Monteriù, Andrea

    2013-07-01

    This paper studies the problem of detecting and isolating faults in linear periodic discrete-time systems. The aim is to design an observer-based residual generator where each residual is sensitive to one fault, whilst remaining insensitive to the other faults that can affect the system. Making use of the geometric tools, and in particular of the outer observable subspace notion, the Fault Detection and Isolation (FDI) problem is formulated and necessary and solvability conditions are given. An algorithmic procedure is described to determine the solution of the FDI problem.

  20. Time Periodic Electro-Osmotic-Flow of Jeffrey Fluid in a Circular Microtube

    NASA Astrophysics Data System (ADS)

    Jian, Y. J.; Liu, Q. S.; Duan, H. Z.; Chang, L.; Yang, L. G.

    2011-09-01

    Flow behavior of time periodic electro-osmotic flow (EOF) of non-Newtonian (Jeffrey) fluids in a circular microtube is investigated based on a linearized Poisson-Boltzmann equation, together with the Cauchy momentum equation and the Jeffrey constitutive equation. Taking near-wall depletion effects of macromolecules into account, we divided the flow region into skimming layer and the bulk. Analytical solutions of EOF velocity distribution are obtained. By numerical computations, the influences of the related parameters on the velocity amplitude are studied.

  1. Testing aggregation hypotheses among Neotropical trees and shrubs: results from a 50-ha plot over 20 years of sampling.

    PubMed

    Myster, Randall W; Malahy, Michael P

    2012-09-01

    Spatial patterns of tropical trees and shrubs are important to understanding their interaction and the resultant structure of tropical rainforests. To assess this issue, we took advantage of previously collected data, on Neotropical tree and shrub stem identified to species and mapped for spatial coordinates in a 50ha plot, with a frequency of every five years and over a 20 year period. These stems data were first placed into four groups, regardless of species, depending on their location in the vertical strata of the rainforest (shrubs, understory trees, mid-sized trees, tall trees) and then used to generate aggregation patterns for each sampling year. We found shrubs and understory trees clumped at small spatial scales of a few meters for several of the years sampled. Alternatively, mid-sized trees and tall trees did not clump, nor did they show uniform (regular) patterns, during any sampling period. In general (1) groups found higher in the canopy did not show aggregation on the ground and (2) the spatial patterns of all four groups showed similarity among different sampling years, thereby supporting a "shifting mosaic" view of plant communities over large areas. Spatial analysis, such as this one, are critical to understanding and predicting tree spaces, tree-tree replacements and the Neotropical forest patterns, such as biodiversity and those needed for sustainability efforts, they produce.

  2. Evolution of illustrations in anatomy: a study from the classical period in Europe to modern times.

    PubMed

    Ghosh, Sanjib Kumar

    2015-01-01

    Illustrations constitute an essential element of learning anatomy in modern times. However it required a significant evolutionary process spread over centuries, for illustrations to achieve the present status in the subject of anatomy. This review article attempts to outline the evolutionary process by highlighting on the works of esteemed anatomists in a chronological manner. Available literature suggests that illustrations were not used in anatomy during the classical period when the subject was dominated by the descriptive text of Galen. Guido da Vigevano was first to use illustrations in anatomy during the Late Middle Ages and this concept developed further during the Renaissance period when Andreas Vesalius pioneered in illustrations becoming an indispensable tool in conveying anatomical details. Toward later stages of the Renaissance period, Fabricius ab Aquapendente endeavored to restrict dramatization of anatomical illustrations which was a prevalent trend in early Renaissance. During the 18th century, anatomical artwork was characterized by the individual styles of prominent anatomists leading to suppression of anatomical details. In the 19th century, Henry Gray used illustrations in his anatomical masterpiece that focused on depicting anatomical structures and were free from any artistic style. From early part of the 20th century medical images and photographs started to complement traditional handmade anatomical illustrations. Computer technology and advanced software systems played a key role in the evolution of anatomical illustrations during the late 20th century resulting in new generation 3D image datasets that are being used in the 21st century in innovative formats for teaching and learning anatomy.

  3. A Report to the People. 20 Years of Your National Commitment to Public Broadcasting, 1967-1987. 1986 Annual Report.

    ERIC Educational Resources Information Center

    Corporation for Public Broadcasting, Washington, DC.

    This annual report for the Corporation for Public Broadcasting (CPB) for fiscal year 1986 also summarizes the CPB's activities over the last 20 years. The front inside cover folds out to three pages and provides a chronology of the important events in CPB history from its inception in 1967 to 1987. A narrative report on the CPB's 20 years of…

  4. Space-time Cooperative Symmetry in a Periodically Driven Tight Binding Model

    NASA Astrophysics Data System (ADS)

    Inoue, Jun-ichi

    2017-02-01

    In recent extensive studies of emergent phenomena in solid-state and cold atomic systems, alteration of the symmetry inherent to a given system by applying an external time-dependent field is a central issue. We have found that how the time reversal symmetry is broken is not solely determined by temporal aspects, but also committed to spatial symmetry of the system. This connection between spatial and temporal symmetries induces various interesting phenomena that have not yet been discussed. This work reports one of these: symmetry-protected band sticking together in an effective-energy band structure of periodically driven electron systems. Experiments that could be used to observe the effect are discussed. The findings reported herein will contribute to a deeper understanding of the underlying physics and guiding principles of Floquet engineering.

  5. The effects of time-periodic shear on a diffusion flame anchored to a propellant

    SciTech Connect

    Buckmaster, J.; Jackson, T.L.

    2000-01-01

    The authors examine a single diffusion flame anchored to 1/4-spaces of solid fuel and oxidizer, a configuration relevant to the combustion of heterogeneous solid propellants. A time-periodic shear flow is applied, to model the shear that can be generated by the interaction of acoustic waves and the rotational base flow in a rocket chamber. The response of the flame to this shear, the heat flux to the surface, etc., are calculated numerically. Significant enhancement of the maximum temperature and the time-averaged total heat flux to the surface re found. These enhancements are essentially maximized at zero frequency, and at low frequencies the response depends critically on the instantaneous direction of the shear.

  6. Detection of periodic signal of arbitrary shape with random time delay

    NASA Astrophysics Data System (ADS)

    Ansari, K. A.

    1985-06-01

    The detection of periodic signals of arbitrary wave shape with random time delay in additive white Gaussian noise, is a problem of practical significance in radar and communication applications. In this thesis, the analysis and design of optimum and suboptimum receivers for detecting signals as described above has been carried out. The design of optimum (in minimum probability of error, Pe sense) receivers is based on the likelihood ratio test under the assumption of low SNR conditions. The design of suboptimum receivers is based on the heuristic approaches that intuitively yield reasonably good performance. Examples have been analyzed in order to present numerical results in graphical form on the performance of the receivers under different assumptions of wave ships and p.d.f. on the random time delay associated with the signal.

  7. On Bifurcating Time-Periodic Flow of a Navier-Stokes Liquid Past a Cylinder

    NASA Astrophysics Data System (ADS)

    Galdi, Giovanni P.

    2016-10-01

    We provide general sufficient conditions for the existence and uniqueness of branching out of a time-periodic family of solutions from steady-state solutions to the two-dimensional Navier-Stokes equations in the exterior of a cylinder. By separating the time-independent averaged component of the velocity field from its oscillatory one, we show that the problem can be formulated as a coupled elliptic-parabolic nonlinear system in appropriate and distinct function spaces, with the property that the relevant linearized operators become Fredholm of index 0. In this functional setting, the notorious difficulty of 0 being in the essential spectrum entirely disappears and, in fact, it is even meaningless. Our approach is different and, we believe, more natural and simpler than those proposed by previous authors discussing similar questions. Moreover, the latter all fail, when applied to the problem studied here.

  8. Nonlinear time-periodic models of the longitudinal flight dynamics of desert locusts Schistocerca gregaria.

    PubMed

    Taylor, Graham K; Zbikowski, Rafał

    2005-06-22

    Previous studies of insect flight control have been statistical in approach, simply correlating wing kinematics with body kinematics or force production. Kinematics and forces are linked by Newtonian mechanics, so adopting a dynamics-based approach is necessary if we are to place the study of insect flight on its proper physical footing. Here we develop semi-empirical models of the longitudinal flight dynamics of desert locusts Schistocerca gregaria. We use instantaneous force-moment measurements from individual locusts to parametrize the nonlinear rigid body equations of motion. Since the instantaneous forces are approximately periodic, we represent them using Fourier series, which are embedded in the equations of motion to give a nonlinear time-periodic (NLTP) model. This is a proper mathematical generalization of an earlier linear-time invariant (LTI) model of locust flight dynamics, developed using previously published time-averaged versions of the instantaneous force recordings. We perform various numerical simulations, within the fitted range of the model, and across the range of body angles used by free-flying locusts, to explore the likely behaviour of the locusts upon release from the tether. Solutions of the NLTP models are compared with solutions of the nonlinear time-invariant (NLTI) models to which they reduce when the periodic terms are dropped. Both sets of models are unstable and therefore fail to explain locust flight stability fully. Nevertheless, whereas the measured forces include statistically significant harmonic content up to about the eighth harmonic, the simulated flight trajectories display no harmonic content above the fundamental forcing frequency. Hence, manoeuvre control in locusts will not directly reflect subtle changes in the higher harmonics of the wing beat, but must operate on a coarser time-scale. A state-space analysis of the NLTP models reveals orbital trajectories that are impossible to capture in the LTI and NLTI models, and

  9. Effect of fluconazole on viability of Candida albicans over extended periods of time.

    PubMed Central

    Sohnle, P G; Hahn, B L; Erdmann, M D

    1996-01-01

    The treatment of chronic mycoses may expose the infecting organisms to antimicrobial agents for extended periods of time. It is possible that an azole antifungal drug such as fluconazole, with primarily fungistatic activity in standard in vitro susceptibility tests, might be able to damage the fungal cells and reduce their viability over prolonged incubations under nonproliferating conditions. To test this possibility, Candida albicans yeast cells were exposed to various concentrations of fluconazole in RPMI 1640 tissue culture medium for 4 h at 37 degrees C, washed free of the drug, and then incubated at 37 degrees C for a 28-day period; enumeration of the remaining CFU at various times during this period revealed no increased loss of viability for the fluconazole-exposed organisms. However, when fluconazole was added to the organisms maintained in distilled water (with or without pretreatment with the drug), a marked reduction of viability was found. At 14 days of incubation with two strains of C. albicans, negative cultures were found for 7 of 10 and 10 of 11 samples, respectively, containing 1.0 microgram of fluconazole per ml versus 0 of 10 and 1 of 11 control samples (P of < 0.01 and 0.001, respectively). The effect of fluconazole on fungal viability under these conditions became noticeable at approximately 7 days and was greater when the samples were incubated at 37 degrees C rather than 25 degrees C. These findings suggest that fluconazole may have fungicidal effects on fungal cells during prolonged exposures under conditions in which the organisms are prevented from proliferating by lack of nutrients. PMID:8913476

  10. Compensatory mechanisms in higher-educated subjects with Alzheimer's disease: a study of 20 years of cognitive decline.

    PubMed

    Amieva, Hélène; Mokri, Hind; Le Goff, Mélanie; Meillon, Céline; Jacqmin-Gadda, Hélène; Foubert-Samier, Alexandra; Orgogozo, Jean-Marc; Stern, Yaakov; Dartigues, Jean-François

    2014-04-01

    A better knowledge of long-term trajectories of cognitive decline is a central feature of the study of the process leading to Alzheimer's dementia. Several factors may mitigate such decline, among which is education, a major risk factor for Alzheimer's disease. The aim of our work was to compare the pattern and duration of clinical trajectories before Alzheimer's dementia in individuals with low and high education within the PAQUID cohort involving 20 years of follow-up. The sample comprises 442 participants with incident Alzheimer's disease (27.2% were male)--171 with low education (mean age=86.2 years; standard deviation=5.3 years) and 271 with higher education (mean age=86.5; standard deviation=5.4)--and 442 control subjects matched according to age, sex and education. At each visit and up to the 20-year follow-up visit, several cognitive and clinical measures were collected and incident cases of Alzheimer's disease clinically diagnosed. The evolution of clinical measures in pre-demented subjects and matched controls was analysed with a semi-parametric extension of the mixed effects linear model. The results show that the first signs of cognitive decline occurred 15 to 16 years before achieving dementia threshold in higher-educated subjects whereas signs occurred at 7 years before dementia in low-educated subjects. There seemed to be two successive periods of decline in higher-educated subjects. Decline started ∼15 to 16 years before dementia with subtle impairment restricted to some cognitive tests and with no impact during the first 7 to 8 years on global cognition, cognitive complaints, or activities of daily living scales. Then, ∼7 years before dementia, global cognitive abilities begin to deteriorate, along with difficulties dealing with complex activities of daily living, the increase in self-perceived difficulties and depressive symptoms. By contrast, lower-educated subjects presented a single period of decline lasting ∼7 years, characterized by

  11. The changes of subtypes in pediatric diabetes and their clinical and laboratory characteristics over the last 20 years

    PubMed Central

    Kwon, Eun Byul; Lee, Hae Sang; Shim, Young Seok; Jeong, Hwal Rim

    2016-01-01

    Purpose We studied the changes in subtypes of diabetes mellitus (DM) in children and evaluated the characteristics of each group over the past 20 years. In addition, we also examined the correlation between the glycated hemoglobin (HbA1c) values at the time of diagnosis and lipid profiles. Methods The patients were divided into 2 groups: there were a total of 190 patients under 20 years of age firstly diagnosed with DM in Ajou University Hospital. The patients in groups I and II were diagnosed from September 1995 to December 2004 and from January 2005 to April 2014, respectively. Results The characteristics were compared between the 2 groups of patients. The result showed an increase in percentage of type 2 diabetes and maturity onset diabetes of the young (MODY) patients between the 2 groups. HbA1c and total cholesterol level had statistical significances to explain increasing the low-density lipoprotein cholesterol level among age, HbA1c, total cholesterol level, and z-scores of weight and body mass index (BMI) in type 2 diabetes. R-square was 0.074. However, z-score of BMI and total cholesterol level, not HbA1c, had statistical significances in type 1 diabetic patients. R-square was 0.323. Conclusion The increase in the proportions of both type 2 diabetes and MODY in the last 10 years needed to be reminded when diagnosing the subtypes of DM, and the dyslipidemia should be attended more as a common problem of pediatric diabetic patients. PMID:27462584

  12. Sex differences in mathematical reasoning ability at age 13: their status 20 years later.

    PubMed

    Benbow, C P; Lubinski, D; Shea, D L; Eftekhari-Sanjani, H

    2000-11-01

    Reported is the 20-year follow-up of 1,975 mathematically gifted adolescents (top 1%) whose assessments at age 12 to 14 revealed robust gender differences in mathematical reasoning ability. Both sexes became exceptional achievers and perceived themselves as such; they reported uniformly high levels of degree attainment and satisfaction with both their career direction and their overall success. The earlier sex differences in mathematical reasoning ability did predict differential educational and occupational outcomes. The observed differences also appeared to be a function of sex differences in preferences for (a) inorganic versus organic disciplines and (b) a career-focused versus more-balanced life. Because profile differences in abilities and preferences are longitudinally stable, males probably will remain more represented in some disciplines, whereas females are likely to remain more represented in others. These data have policy implications for higher education and the world of work.

  13. Age-associated losses of brain volume predict longitudinal cognitive declines over 8 to 20 years.

    PubMed

    Rabbitt, Patrick; Ibrahim, Said; Lunn, Mary; Scott, Marietta; Thacker, Neil; Hutchinson, Charles; Horan, Michael; Pendleton, Neil; Jackson, Alan

    2008-01-01

    Absolute differences in global brain volume predict differences in cognitive ability among healthy older adults. However, absolute differences confound lifelong differences in brain size with amounts of age-related shrinkage. Measurements of cerebrospinal fluid (CSF) volume were made to estimate age-related shrinkage in 93 healthy volunteers aged 63 to 86 years. Their current levels of brain shrinkage predicted their amounts of decline over the previous 8 to 20 years on repeated assessments during a longitudinal study on the Cattell "Culture Fair" Intelligence Test, on two tests of information processing speed, and marginally on the Wechsler Adult Intelligence Scale (D. Wechsler, 1981), but not on three memory tests. Loss of brain volume is an effective marker both for current cognitive status and for amounts and rates of previous age-related cognitive losses.

  14. How do animal territories form and change? Lessons from 20 years of mechanistic modelling

    PubMed Central

    Potts, Jonathan R.; Lewis, Mark A.

    2014-01-01

    Territory formation is ubiquitous throughout the animal kingdom. At the individual level, various behaviours attempt to exclude conspecifics from regions of space. At the population level, animals often segregate into distinct territorial areas. Consequently, it should be possible to derive territorial patterns from the underlying behavioural processes of animal movements and interactions. Such derivations are an important element in the development of an ecological theory that can predict the effects of changing conditions on territorial populations. Here, we review the approaches developed over the past 20 years or so, which go under the umbrella of ‘mechanistic territorial models’. We detail the two main strands to this research: partial differential equations and individual-based approaches, showing what each has offered to our understanding of territoriality and how they can be unified. We explain how they are related to other approaches to studying territories and home ranges, and point towards possible future directions. PMID:24741017

  15. Cuban Meningococcal BC Vaccine: Experiences & Contributions from 20 Years of Application.

    PubMed

    Sotolongo, Franklin; Campa, Concepción; Casanueva, Victoria; Fajardo, Esther María; Cuevas, Iván Edelberto; González, Noel

    2008-10-01

    This paper reviews 20 years of experience and scientific contributions of the Cuban meningococcal BC vaccine (VA-MENGOC-BC®) obtained by the Finlay Institute in Havana, Cuba. The vaccine is the first of its type in the world that is safe, effective, and commercially available for preventing meningococcal disease caused by serogroup B meningococcus; it is also effective against serogroup C. VA-MENGOC-BC® has shown satisfactory results, with no serious adverse events, after application of approximately 55 million doses in some 15 countries. Also included is background information on meningococcal disease, as well as the main characteristics of VA-MENGOC-BC®, the strategy used for controlling meningococcal disease and its prevention in Cuba, and a summary of the main scientific results obtained in basic research, development, clinical evaluation, and post-marketing results (safety, efficacy-effectiveness, post-vaccination adverse events, etc.) in Cuba and elsewhere.

  16. Cuban Meningococcal BC Vaccine: Experiences & Contributions from 20 Years of Application.

    PubMed

    Sotolongo, Franklin; Campa, Concepción; Casanueva, Victoria; Fajardo, Esther María; Cuevas, Iván Edelberto; González, Noel

    2007-10-01

    This paper reviews 20 years of experience and scientific contributions of the Cuban meningococcal BC vaccine (VA-MENGOC-BC®) obtained by the Finlay Institute in Havana, Cuba. The vaccine is the first of its type in the world that is safe, effective, and commercially available for preventing meningococcal disease caused by serogroup B meningococcus; it is also effective against serogroup C. VA-MENGOC-BC® has shown satisfactory results, with no serious adverse events, after application of approximately 55 million doses in some 15 countries. Also included is background information on meningococcal disease, as well as the main characteristics of VA-MENGOC-BC®, the strategy used for controlling meningococcal disease and its prevention in Cuba, and a summary of the main scientific results obtained in basic research, development, clinical evaluation, and post-marketing results (safety, efficacy-effectiveness, post-vaccination adverse events, etc.) in Cuba and elsewhere.

  17. [20 years of a sex education clinic. Are family planning centers still needed?].

    PubMed

    Alfsen, G C; Hokstad, S

    1992-02-28

    The Sexual Information Clinic in Oslo was founded more than 20 years ago. The clinic is the largest family planning centre in Norway, treating 4,000-6,000 patients per year. In recent years the treatment of venereal diseases has become the major component of the daily work. The authors describe the different groups of patients who visit the clinic. The meanage of the patients is 21 years. The high number of legal abortions among younger women and the rising incidence of sexually transmitted diseases prove the continued existence of a need for family planning centres. The authors discuss the situation of family planning centres in Norway in general and stress the importance of their work. They argue that all venereal diseases should be treated free of charge.

  18. Stability of the interstellar hydrogen inflow longitude from 20 years of SOHO/SWAN observations

    NASA Astrophysics Data System (ADS)

    Koutroumpa, D.; Quémerais, E.; Katushkina, O.; Lallement, R.; Bertaux, J.-L.; Schmidt, W.

    2017-01-01

    Aims: A recent debate on the decade-long stability of the interstellar He flow vector, and in particular the flow longitude, has prompted us to check for any variability in the interstellar H flow vector as observed by the SWAN instrument on board SOHO. Methods: We used a simple model-independent method to determine the interstellar H flow longitude, based on the parallax effects induced on the Lyman-α intensity measured by SWAN following the satellite motion around the Sun. Results: Our results show that the interstellar H flow vector longitude does not vary significantly from an average value of 252.9°± 1.4° throughout the 20-year span of the SWAN dataset, further strengthening the arguments for the stability of the interstellar gas flow.

  19. Factitious aortic dissection leading to thoracotomy in a 20-year-old man.

    PubMed

    Chambers, Elise; Yager, Joel; Apfeldorf, William; Camps-Romero, Eduardo

    2007-01-01

    A 20-year-old man presented to an emergency department with dramatic, sudden-onset, tearing chest pain. He also claimed to have been previously diagnosed with Ehler-Danlos syndrome and a previous Type I aortic dissection (intimal tear of ascending aorta), rapidly increasing his treating physician's suspicion of an emergent aortic dissection. The patient was quickly transferred to a large university hospital, where he underwent a median sternotomy and thoracotomy, with no aortic pathology found on operation and biopsy. After the patient's postoperative recovery, he was treated at a mental health facility, where he remained ambivalent about his psychiatric condition and did not respond well to treatment. This case report describes a unique case of factitious disorder that led to a serious operative intervention and subsequent psychiatric care and assesses factors that might have contributed to his hospital course.

  20. [Meeting Report: 20 years after the First International Symposium on hepatitis C virus and related viruses].

    PubMed

    Carnero, Elena; Díez, Juana; Fortes, Purificación; Gastaminza, Pablo; Majano, Pedro; Martínez, Miguel Angel; Pérez-del-Pulgar, Sofía; Quer, Josep; López-Labrador, F Xavier

    2013-12-01

    The hepatitis C virus (HCV) was discovered by the team of Michael Houghton at Chiron Corporation in 1989 and the first symposium on HCV and related viruses was held in Venice, Italy, shortly after, in 1992. This conference was organized to advance knowledge on what then was a mysterious virus responsible for most cases of «non-A, non-B» hepatitis. During the 20 years since the first conference, the scientific quality of presentations has steadily increased, together with the tremendous advances in basic and clinical research and epidemiology. What started as a small conference on a new virus, about which there were very few data, has today become a first-in-class congress: a meeting place for basic researchers, clinicians, epidemiologists, public health experts, and industry members to present the most important advances and their application to HCV treatment and control. The nineteenth HCV symposium was held in September 2012, once again in Venice.

  1. [Improvements in the diagnosis of dystrophinopathies: what have we learnt in these last 20 years?].

    PubMed

    López-Hernández, Luz B; Ayala-Madrigal, M Luz; van Heusden, Dave; Estrada-Mena, Francisco J; Canto, Patricia; Sandoval-Ramírez, Lucila; Gómez-Díaz, Benjamín; Coral-Vázquez, Ramón M

    2011-02-16

    INTRODUCTION. Dystrophinopathies are X-linked genetic disorders caused by mutations in the DMD gene. Genetic tests are of utmost importance for management and genetic counseling of these diseases. However, the complexity of the DMD gene is a challenge for diagnosis. AIM. To describe recent advances in the diagnosis of dystrophinopathies, after 20 years since the firsts molecular assays for genetic screening for these diseases. DEVELOPMENT. Currently, a variety of strategies such as automated mutation detection, cell-based methods and high throughput haplotyping have been developed to facilitate diagnosis of dystrophinopathies, carrier detection, prenatal and preimplantation diagnosis. CONCLUSION. New technologies have improved early detection and optimal management of dystrophinopathies and have established the basis for future molecular medicine. The most significant advances in dystrophinopathy diagnosis are reviewed herein.

  2. [Familial Mediterranean fever in Mexico City. A 20-year follow-up].

    PubMed

    Halabe-Cherem, José; Pérez-Jiménez, Carolina; Nellen-Hummel, Haiko; Mercado-Atri, Moisés; Sigala-Rodríguez, Carolina; Castañón-González, Jorge

    2004-01-01

    Familial Mediterranean fever (MFF) is an autosomic recessive, inherited inflammatory disease principally seen in persons from the Mediterranean area. Clinical findings include fever, abdominal pain, and pleuritis. The most severe complication of MFF is renal amyloidosis, manifested as nephrotic syndrome, which evolves into chronic renal failure. In this study, we described clinical findings, evolution, and response to treatment in 52 patients diagnosed with MFF living in Mexico City in whom the most important clinical features were fever and abdominal pain. Differing from previous reported series of patients from the Mediterranean area, patient developed renal amyloidosis during the 20-year follow-up, which suggests that an environmental factor might have a significant influence in development of renal amyloidosis.

  3. Role of 3-D ultrasound in clinical obstetric practice: evolution over 20 years.

    PubMed

    Tonni, Gabriele; Martins, Wellington P; Guimarães Filho, Hélio; Araujo Júnior, Edward

    2015-05-01

    The use of 3-D ultrasound in obstetrics has undergone dramatic development over the past 20 years. Since the first publications on this application in clinical practice, several 3-D ultrasound techniques and rendering modes have been proposed and applied to the study of fetal brain, face and cardiac anatomy. In addition, 3-D ultrasound has improved calculations of the volume of fetal organs and limbs and estimations of fetal birth weight. And furthermore, angiographic patterns of fetal organs and the placenta have been assessed using 3-D power Doppler ultrasound quantification. In this review, we aim to summarize current evidence on the clinical relevance of these methodologies and their application in obstetric practice.

  4. Australian Aboriginal Birth Cohort study: follow-up processes at 20 years

    PubMed Central

    2009-01-01

    Background In 1987, a prospective study of an Australian Aboriginal Birth Cohort was established focusing on the relationships of fetal and childhood growth with the risk of chronic adult disease. However as the study is being conducted in a highly marginalized population it is also an important resource for cross-sectional descriptive and analytical studies. The aim of this paper is to describe the processes of the third follow up which was conducted 20 years after recruitment at birth. Methods Progressive steps in a multiphase protocol were used for tracing, with modifications for the expected rural or urban location of the participants. Results Of the original 686 cohort participants recruited 68 were untraced and 27 were known to have died. Of the 591 available for examination 122 were not examined; 11 of these were refusals and the remainder were not seen for logistical reasons relating to inclement weather, mobility of participants and single participants living in very remote locations. Conclusion The high retention rate of this follow-up 20 years after birth recruitment is a testament to the development of successful multiphase protocols aimed at overcoming the challenges of tracing a cohort over a widespread remote area and also to the perseverance of the study personnel. We also interpret the high retention rate as a reflection of the good will of the wider Aboriginal community towards this study and that researchers interactions with the community were positive. The continued follow-up of this life course study now seems feasible and there are plans to trace and reexamine the cohort at age 25 years. PMID:19775475

  5. Cardiac Magnetic Resonance Imaging Findings in 20-year Survivors of Mediastinal Radiotherapy for Hodgkin's Disease

    SciTech Connect

    Machann, Wolfram; Beer, Meinrad; Breunig, Margret; Stoerk, Stefan; Angermann, Christiane; Seufert, Ines; Schwab, Franz; Koelbl, Oliver; Flentje, Michael; Vordermark, Dirk

    2011-03-15

    Purpose: The recognition of the true prevalence of cardiac toxicity after mediastinal radiotherapy requires very long follow-up and a precise diagnostic procedure. Cardiac magnetic resonance imaging (MRI) permits excellent quantification of cardiac function and identification of localized myocardial defects and has now been applied to a group of 20-year Hodgkin's disease survivors. Methods and materials: Of 143 patients treated with anterior mediastinal radiotherapy (cobalt-60, median prescribed dose 40 Gy) for Hodgkin's disease between 1978 and 1985, all 53 survivors were invited for cardiac MRI. Of those, 36 patients (68%) presented for MRI, and in 31 patients (58%) MRI could be performed 20-28 years (median, 24) after radiotherapy. The following sequences were acquired on a 1.5-T MRI: transversal T1-weighted TSE and T2-weighted half-fourier acquisition single-shot turbo-spin-echo sequences, a steady-state free precession (SSFP) cine sequence in the short heart axis and in the four-chamber view, SSFP perfusion sequences under rest and adenosine stress, and a SSFP inversion recovery sequence for late enhancement. The MRI findings were correlated with previously reconstructed doses to cardiac structures. Results: Clinical characteristics and reconstructed doses were not significantly different between survivors undergoing and not undergoing MRI. Pathologic findings were reduced left ventricular function (ejection fraction <55%) in 7 (23%) patients, hemodynamically relevant valvular dysfunction in 13 (42%), late myocardial enhancement in 9 (29%), and any perfusion deficit in 21 (68%). An association of regional pathologic changes and reconstructed dose to cardiac structures could not be established. Conclusions: In 20-year survivors of Hodgkin's disease, cardiac MRI detects pathologic findings in approximately 70% of patients. Cardiac MRI has a potential role in cardiac imaging of Hodgkin's disease patients after mediastinal radiotherapy.

  6. Characteristics of dissolved organic matter following 20years of peatland restoration.

    PubMed

    Höll, Bettina S; Fiedler, Sabine; Jungkunst, Hermann F; Kalbitz, Karsten; Freibauer, Annette; Drösler, Matthias; Stahr, Karl

    2009-12-15

    The changes in the amounts and composition of dissolved organic matter (DOM) following long-term peat restoration are unknown, although this fraction of soil organic matter affects many processes in such ecosystems. We addressed this lack of knowledge by investigating a peatland in south-west Germany that was partly rewetted 20 years ago. A successfully restored site and a moderately drained site were compared, where the mean groundwater levels were close to the soil surface and around 30 cm below surface, respectively. The concentrations of dissolved organic carbon (DOC) at 4 depths were measured over one year. The specific absorbance was measured at 280 nm and the fluorescence spectra were used to describe the aromaticity and complexity of DOM. The investigations showed that 20 years of peatland restoration was able to create typical peatland conditions. The rewetted site had significantly lower DOC concentrations at different depths compared to the drained site. The specific UV absorbance showed that the rewetted site had a lower level of aromatic DOM structures. The decreasing specific UV absorbance might indicate an increasing contribution of small organic molecules to DOM. It was hypothesized that the decreasing DOC concentrations and the relative enrichment of small, readily degradable organic molecules, reflect the slower decomposition of organic matter after the re-establishment of the water table. Seasonal trends provided substantial evidence for our hypothesis that reduced DOC concentrations were caused by reduced peat decomposition. During summer, the elevated DOC values were accompanied by an increase in DOM aromaticity and complexity. Our results demonstrated a close link between C mineralization and DOC production. We concluded that long-term peatland restoration in the form of the successful re-establishment of the water table might result in reduced peat decomposition and lower DOC concentrations. The restoration of peatlands seems to have a

  7. Anterior cruciate ligament injury after more than 20 years: I. Physical activity level and knee function.

    PubMed

    Tengman, E; Brax Olofsson, L; Nilsson, K G; Tegner, Y; Lundgren, L; Häger, C K

    2014-12-01

    Little is known about physical activity level and knee function including jump capacity and fear of movement/reinjury more than 20 years after injury of the anterior cruciate ligament (ACL). Seventy persons with unilateral ACL injury participated (23 ± 2 years post-injury): 33 treated with physiotherapy in combination with surgical reconstruction (ACLR ), and 37 treated with physiotherapy alone (ACLPT ). These were compared with 33 age- and gender-matched controls. Assessment included knee-specific and general physical activity level [Tegner activity scale, International Physical Activity Questionnaire (IPAQ)], knee function [Lysholm score, Knee injury and Osteoarthritis Outcome Score (KOOS)], jump capacity (one-leg hop, vertical jump, side hops), and fear of movement/reinjury [Tampa Scale for Kinesiophobia (TSK)]. Outcomes were related to degree of osteoarthritis (OA). ACL-injured had lower Lysholm, KOOS, and Tegner scores than controls (P < 0.001), while IPAQ score was similar. ACL-injured demonstrated inferior jump capacity in injured compared with noninjured leg (6-25%, P < 0.001-P = 0.010 in the different jumps), while noninjured leg had equal jump capacity as controls. ACL groups scored 33 ± 7 and 32 ± 7 of 68 on TSK. Lower scores on Lysholm and KOOS symptom were seen for persons with moderate-to-high OA than for no-or-low OA, while there were no differences for physical activity and jump capacity. Regardless of treatment, there are still negative knee-related effects of ACL injury more than 20 years later.

  8. Temporal and Spatial Trends of Mercury Speciation in the Mediterranean Sea - 20 years of measurements

    NASA Astrophysics Data System (ADS)

    Horvat, M.; Kotnik, J.; Fajon, V.; Zivkovic, I.; Begu, E.; Pirrone, N.; Sprovieri, F.

    2015-12-01

    Despite the geological mercury anomaly in the Mediterranean Basin, the concentrations of Hg Hg and its compounds are generally lower than those found in the Atlantic and Pacific waters. Temporal and spatial trends of total mercury and its species in surface and deep waters (dissolved gaseous mercury - DGM, mono and di-methylmercuy - MMHg, and DMHg) obtained during last 20 years will be presented. Total mercury Hg levels in open waters are generally very low (0.81-2.33 pM, av. 1.46 pM) and remain constant over the years. Hg speciation data showed that DGM accounts for up to 50% while MMHg accounted to up to 15% of total Hg in water. Significant spatial and temporal differences were observed for mercury speciation. The relatively high concentrations and fractions of DGM and MMHg indicate the high reactivity of Hg in open marine waters. DGM was present in surface waters mainly as Hg0 as no DMHg was detected at the surface, while towards the bottom a noticeable, but relatively small fraction of DMHg was present. It was found that DGM species were lower in surface with an increasing trend towards the bottom, especially in the tectonically active areas, indicating its geotectonic origin. In surface waters, DGM exhibited higher values in summer. MMHg profiles are mostly related to Chl-a and oxygen concentrations. This underlines the role of planktonic production and regeneration in methylation/ demethylation processes. The low MMHg concentrations found in shelf edge or coastal sediments and water over sediment indicate that coastal or shelf sediments are not a significant MMHg source for adjacent open sea waters. Anthropogenic and natural point sources show local enrichments, while natural diffusive sources influence Hg speciation over larger areas. The results allowed estimation of temporal mass balances to be evaluated for the Mediterranean Sea. Comparability of the measured results was secured by strict quality control measures over the 20 years.

  9. A History of the Environmental Management Advisory Board: 20 Years of Service and Partnership - 13219

    SciTech Connect

    Ellis, Kristen; Schmitt, Elizabeth

    2013-07-01

    The Environmental Management Advisory Board (EMAB or Board) was chartered under the Federal Advisory Committee Act (FACA) in 1992 to provide the Assistant Secretary for Environmental Management (EM) with independent and external advice, information, and recommendations on corporate issues relating to accelerated site clean-up and risk reduction throughout the EM complex. Over the course of the past 20 years, the composition and focus of the Board have varied widely to address the changing needs of the program. EMAB began as the Environmental Restoration and Waste Management Advisory Committee, formed to provide advice on an EM Programmatic Environmental Impact Statement. In 1994, the Board was restructured to function more as an executive-level, limited member advisory board whose membership provides insight of leading industry experts and the viewpoints of representatives from critical stakeholder constituencies. Throughout the 20 years of its existence, EMAB has covered a wide variety of topics and produced nearly 200 recommendations. These recommendations have resulted in several policy changes and improvements within EM. Most recently, EMAB has been credited for its contribution to the EM Energy Park Initiative, forerunner of the DOE Asset Revitalization Initiative; creation of the EM Offices of Communications and External Affairs; improvement of acquisition and project management strategies and culture; and several recommendations related to the Waste Treatment Plant and the tank waste programs at Hanford and the Savannah River Site. The wealth of experience and knowledge the Assistant Secretary can leverage through utilization of the Board continues to support fulfillment of EM's mission. In commemoration of EMAB's 20. anniversary, this paper will provide further context for the evolution of the Board, the role FACA plays in its administration, and a look at the members' current objectives and EM's expectations for the future. (authors)

  10. Observations and predictions of eclipse times by astronomers in the pre-telescopic period.

    NASA Astrophysics Data System (ADS)

    Steele, J. M.

    Eclipses of the Sun and Moon are among the most impressive of celestial events. It is therefore unsurprising that they have played an important role in the astronomy and astrology of most early cultures. Many hundreds of references to eclipses are found in the writings of the chroniclers and astronomers of the pre-telescopic world. In particular, the astronomers of Babylon, Ancient Greece, the Islamic Near East. Later Medieval and Renaissance Europe, China, and Japan, recorded a large number of observations and predictions of the time of an eclipse. The present study contains an extensive compilation of all known timed reports of eclipse observations and predictions made by astronomers in the pre-telescopic period. By performing a basic analysis of the recorded times, it has been possible to trace the gradual development of the techniques used by the astronomers to observe and predict eclipses. In order to conduct this analysis, it has been necessary to investigate a number of other problems including the dating of damaged observational accounts, the units of time used by the early astronomers, and the methods by which the Babylonians predicted eclipses. Many of these questions have not previously been answered. Therefore, the results of this study provide important information regarding the astronomies of these early cultures.

  11. FORENSIC SCIENCE:: 20 YEARS OF FORENSIC DENTISTRY AT THE UNIVERSITY OF ZAGREB, 1994 - 2014.

    PubMed

    Brkić, Hrvoje

    2014-06-01

    Data from available literature point to an early beginning of Forensic Dentistry in Croatia relating to a post-mortem examination of a female patient after a dental procedure in the 1930s. Later on, there were several mass casualties due to collisions and airplane crashes and a railway accident at the Zagreb Main Railway Station wherein the identity of the victims was established based on dental features. Foreign experts in forensics helped identify those victims, particularly forensic dentists because this specialty was almost unknown in our region at the time. During the twenty-year period of the development of Forensic Dentistry at the University of Zagreb, the School of Dental Medicine, the city of Zagreb and Croatia have become internationally recognised on the forensic map of the world.

  12. Enhanced Transport of Passive Tracers In A Time Periodic Two-dimensional Flow

    NASA Astrophysics Data System (ADS)

    Boffetta, G.; Cencini, M.; Espa, S.; Musacchio, S.

    , investigating systems in which the second condition is violated is much more inter- esting. With this purpose, some experiments have shown how superdiffusion arises in a two-dimensional quasi-geostrophic (planetary-type) flow, where particles can jump for very long time in the same direction performing a Levy flight (Castiglione et al., 2001 ). Moreover, two recent papers (Vulpiani, 1998; Solomon, 2001) show how, also in very simple two-dimensional, time and space periodic cellular flows,anomalous diffusive behaviours can appear. In this paper we present an experimental study of transport in an electromagnetically forced time periodic two-dimensional flow. The flow is generated by applying an electromagnetic forcing on a thin layer of an elec- trolyte solution and reveals in a square grid of alternating vortices. Time dependence can be easily obtained by changing the time dependence of the electric fields. In par- ticular, considering certain values of the imposed oscillation frequencies, particles can display very long jump. Particle Tracking Velocimetry (PTV) is used to measure the flow field. This technique is the most suitable for studying dispersion phenomena in a Lagrangian framework allowing the direct evaluation of particle displacements and related quantities (Cenedese, Querzoli; 2000). Moreover, due to the characteristics of the analyzed flow and to the improvement of the tracking procedure, we have been able to track a great number of particles for time intervals greater than the charac- teristic time-scales of the flow. In order to characterize the time correlations we will evaluate the so-called jumps probabilities with memory which represent the probabil- ities to jump in a given direction conditioned to having experienced jumps in the same direction at previous times. Such statistics will revealed very useful and suitable for detecting the onset of the aforementioned correlations. 2

  13. Pulse propagation through a slab with time-periodic dielectric function ε(t).

    PubMed

    Zurita-Sánchez, Jorge R; Abundis-Patiño, J H; Halevi, P

    2012-02-27

    We describe pulse propagation through a slab with periodic dielectric function ε(t), thus extending our previous investigation for monochromatic incidence [Phys. Rev. A 79, 053821 (2009)]. Based on the concepts of phase and group delays, we prove that, for an incident quasi-monochromatic pulse, the transmitted pulse can be expressed as a superposition of partial pulses that are exact replicas of the incident pulse and that exit the slab with a time delay. These partial pulses have harmonic carrier frequencies ω c - nΩ (n is an integer, ω c is the carrier frequency of the incident pulse, and Ω = 2π/T is the slab modulation frequency). We find numerically that these partial pulses can be fast (peak velocity vn > c or vn < 0) or slow (vn < c). Further, we investigate the peak velocity v p of the outcoming pulse for several cases. We find that this peak velocity v p and the partial peak velocities vn do not diverge--as occurs to the group velocity v g of the bulk dynamic-periodic medium when ω c = Ω/2. We expect that these results could be verified in the microwave regime [see Halevi et al., Proc. SPIE 8095, 80950I (2011)].

  14. Periodic coupling strength-dependent multiple coherence resonance by time delay in Newman-Watts neuronal networks.

    PubMed

    Wu, Yanan; Gong, Yubing; Xu, Bo

    2013-12-01

    Recently, multiple coherence resonance induced by time delay has been observed in neuronal networks with constant coupling strength. In this paper, by employing Newman-Watts Hodgkin-Huxley neuron networks with time-periodic coupling strength, we study how the temporal coherence of spiking behavior and coherence resonance by time delay change when the frequency of periodic coupling strength is varied. It is found that delay induced coherence resonance is dependent on periodic coupling strength and increases when the frequency of periodic coupling strength increases. Periodic coupling strength can also induce multiple coherence resonance, and the coherence resonance occurs when the frequency of periodic coupling strength is approximately multiple of the spiking frequency. These results show that for periodic coupling strength time delay can more frequently optimize the temporal coherence of spiking activity, and periodic coupling strength can repetitively optimize the temporal coherence of spiking activity as well. Frequency locking may be the mechanism for multiple coherence resonance induced by periodic coupling strength. These findings imply that periodic coupling strength is more efficient for enhancing the temporal coherence of spiking activity of neuronal networks, and thus it could play a more important role in improving the time precision of information processing and transmission in neural networks.

  15. Stochastic extinction of tumor cells due to synchronization effect through time periodic treatment in a tumor-immune interaction model

    NASA Astrophysics Data System (ADS)

    Aisu, Ryota; Horita, Takehiko

    The response to a time periodic treatment of the immunotherapy in a stochastic model of tumor-immune interaction is numerically investigated. Due to the effect of synchronization among the intrinsic oscillation and the treatment, an enhanced extinction of the tumor cells is observed. It suggests that compared with the static treatment, by controlling the period of the treatment, the time periodic treatment could be an effective way of treatment leading to tumor extinction.

  16. Dynamical generalized Hurst exponent as a tool to monitor unstable periods in financial time series

    NASA Astrophysics Data System (ADS)

    Morales, Raffaello; Di Matteo, T.; Gramatica, Ruggero; Aste, Tomaso

    2012-06-01

    We investigate the use of the Hurst exponent, dynamically computed over a weighted moving time-window, to evaluate the level of stability/instability of financial firms. Financial firms bailed-out as a consequence of the 2007-2008 credit crisis show a neat increase with time of the generalized Hurst exponent in the period preceding the unfolding of the crisis. Conversely, firms belonging to other market sectors, which suffered the least throughout the crisis, show opposite behaviors. We find that the multifractality of the bailed-out firms increase at the crisis suggesting that the multi fractal properties of the time series are changing. These findings suggest the possibility of using the scaling behavior as a tool to track the level of stability of a firm. In this paper, we introduce a method to compute the generalized Hurst exponent which assigns larger weights to more recent events with respect to older ones. In this way large fluctuations in the remote past are less likely to influence the recent past. We also investigate the scaling associated with the tails of the log-returns distributions and compare this scaling with the scaling associated with the Hurst exponent, observing that the processes underlying the price dynamics of these firms are truly multi-scaling.

  17. A General Time-Periodic Driving Approach to Realize Topological Phases in Cold Atomic Systems.

    PubMed

    Yan, Zhongbo; Li, Bo; Yang, Xiaosen; Wan, Shaolong

    2015-11-06

    For time-reversal symmetric cold atomic insulating systems, it is found that the usual driving approach based on electromagnetic field used in solid state systems loses its power to drive them from trivial regimes to topological regimes if the driven systems still hold time-reversal symmetry (TRS). For such systems, we point out that simply varying the optical lattice potential periodically provides a general and effective way to drive them into topological regimes without breaking their symmetries. Based on this approach, we find that the time-reversal symmetric Kane-Mele model can be effectively driven from the trivial phase to topological phases named as Floquet Quantum Spin Hall insulator. Due to the existence of two gaps in the Floquet system, this novel state of matter can stably host one or two pair of gapless helical states on the same boundary, which suggests this state is not a simple analog of the Quantum Spin Hall insulator. This new driving approach to a system without TRS is also investigated.

  18. Predicting sleep apnoea syndrome from heart period: a time-frequency wavelet analysis.

    PubMed

    Roche, F; Pichot, V; Sforza, E; Court-Fortune, I; Duverney, D; Costes, F; Garet, M; Barthélémy, J C

    2003-12-01

    Heart rate fluctuations are a typical finding during obstructive sleep apnoea, characterised by bradycardia during the apnoeic phase and tachycardia at the restoration of ventilation. In this study, a time-frequency domain analysis of the nocturnal heart rate variability (HRV) was evaluated as the single diagnostic marker for obstructive sleep apnoea syndrome (OSAS). The predictive accuracy of time-frequency HRV variables (wavelet (Wv) decomposition parameters from level 2 (Wv2) to level 256 (Wv256)) obtained from nocturnal electrocardiogram Holter monitoring were analysed in 147 consecutive patients aged 53.8+/-11.2 yrs referred for possible OSAS. OSAS was diagnosed in 66 patients (44.9%) according to an apnoea/hypopnoea index > or = 10. Using receiver-operating characteristic curves analysis, the most powerful predictor variable was Wv32 (W 0.758, p<0.0001), followed by Wv16 (W 0.729, p<0.0001) and Wv64 (W 0.700, p<0.0001). Classification and Regression Trees methodology generated a decision tree for OSAS prediction including all levels of Wv coefficients, from Wv2 to Wv256 with a sensitivity reaching 92.4% and a specificity of 90.1% (percentage of agreement 91.2%) with this nonparametric analysis. Time-frequency parameters calculated using wavelet transform and extracted from the nocturnal heart period analysis appeared as powerful tools for obstructive sleep apnoea syndrome diagnosis.

  19. Sustained and transient attentional processes modulate neural predictors of memory encoding in consecutive time periods.

    PubMed

    Padovani, Tullia; Koenig, Thomas; Eckstein, Doris; Perrig, Walter J

    2013-07-01

    Memory formation is commonly thought to rely on brain activity following an event. Yet, recent research has shown that even brain activity previous to an event can predict later recollection (subsequent memory effect, SME). In order to investigate the attentional sources of the SME, event-related potentials (ERPs) elicited by task cues preceding target words were recorded in a switched task paradigm that was followed by a surprise recognition test. Stay trials, that is, those with the same task as the previous trial, were contrasted with switch trials, which included a task switch compared to the previous trial. The underlying assumption was that sustained attention would be dominant in stay trials and that transient attentional reconfiguration processes would be dominant in switch trials. To determine the SME, local and global statistics of scalp electric fields were used to identify differences between subsequently remembered and forgotten items. Results showed that the SME in stay trials occurred in a time window from 2 to 1 sec before target onset, whereas the SME in switch trials occurred subsequently, in a time window from 1 to 0 sec before target onset. Both SMEs showed a frontal negativity resembling the topography of previously reported effects, which suggests that sustained and transient attentional processes contribute to the prestimulus SME in consecutive time periods.

  20. Caenorhabditis elegans period homolog lin-42 regulates the timing of heterochronic miRNA expression.

    PubMed

    McCulloch, Katherine A; Rougvie, Ann E

    2014-10-28

    MicroRNAs (miRNAs) are small RNAs that regulate gene expression posttranscriptionally via the 3' UTR of target mRNAs and were first identified in the Caenorhabditis elegans heterochronic pathway. miRNAs have since been found in many organisms and have broad functions, including control of differentiation and pluripotency in humans. lin-4 and let-7-family miRNAs regulate developmental timing in C. elegans, and their proper temporal expression ensures cell lineage patterns are correctly timed and sequentially executed. Although much is known about miRNA biogenesis, less is understood about how miRNA expression is timed and regulated. lin-42, the worm homolog of the circadian rhythm gene period of flies and mammals, is another core component of the heterochronic gene pathway. lin-42 mutants have a precocious phenotype, in which later-stage programs are executed too early, but the placement of lin-42 in the timing pathway is unclear. Here, we demonstrate that lin-42 negatively regulates heterochronic miRNA transcription. let-7 and the related miRNA miR-48 accumulate precociously in lin-42 mutants. This defect reflects transcriptional misregulation because enhanced expression of both primary miRNA transcripts (pri-miRNAs) and a let-7 promoter::gfp fusion are observed. The pri-miRNA levels oscillate during larval development, in a pattern reminiscent of lin-42 expression. Importantly, we show that lin-42 is not required for this cycling; instead, peak amplitude is increased. Genetic analyses further confirm that lin-42 acts through let-7 family miRNAs. Taken together, these data show that a key function of lin-42 in developmental timing is to dampen pri-miRNAs levels, preventing their premature expression as mature miRNAs.

  1. Multi Band Insar Analysis of Subsidence Development Based on the Long Period Time Series

    NASA Astrophysics Data System (ADS)

    Çomut, F. C.; Ustun, A.; Lazecky, M.; Aref, M. M.

    2015-12-01

    The SAR Interferometry (InSAR) application has shown great potential in monitoring of land terrain changes and in detection of land deformations such as subsidence. Longer time analysis can lead to understand longer trends and changes. Using different bands of SAR satellite (C- from ERS 1-2 and Envisat, L- from ALOS) over the study area, we achieve knowledge of movements in long-term and evaluation of its dynamic changes within observed period of time. Results from InSAR processing fit with the position changes in vertical direction based on GPS network established over the basin as an effective geodetic network. Time series (StaMPS PS+SB) of several points over Çumra County in eastern part of Konya City show a general trend of the deformation that is expected to be approximately between -13 to -17 mm/year. Northern part of Karaman is affected by faster subsidence, borders of the subsidence trough were identified from Envisat. Presenting InSAR results together with GIS information about locations and time of occurrence of sudden subsidence, urban/industrial growth in time and climate changes helps in better understanding of the situation. This way, the impact of natural and man-made changes will be shown for urban planning thanks to InSAR and GIS comparisons with hydrogeological modeling. In this study we present results of differential and multitemporal InSAR series using different bands and GIS conjunction associated with seasonal and temporal groundwater level changes in Konya Closed Basin.

  2. 40 CFR 270.215 - How are time periods in the requirements in this subpart and my RAP computed?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... requirements in this subpart and my RAP computed? 270.215 Section 270.215 Protection of Environment... HAZARDOUS WASTE PERMIT PROGRAM Remedial Action Plans (RAPs) Operating Under Your Rap § 270.215 How are time periods in the requirements in this subpart and my RAP computed? (a) Any time period scheduled to begin...

  3. 40 CFR 270.215 - How are time periods in the requirements in this subpart and my RAP computed?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... requirements in this subpart and my RAP computed? 270.215 Section 270.215 Protection of Environment... HAZARDOUS WASTE PERMIT PROGRAM Remedial Action Plans (RAPs) Operating Under Your Rap § 270.215 How are time periods in the requirements in this subpart and my RAP computed? (a) Any time period scheduled to begin...

  4. 40 CFR 270.215 - How are time periods in the requirements in this subpart and my RAP computed?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... requirements in this subpart and my RAP computed? 270.215 Section 270.215 Protection of Environment... HAZARDOUS WASTE PERMIT PROGRAM Remedial Action Plans (RAPs) Operating Under Your Rap § 270.215 How are time periods in the requirements in this subpart and my RAP computed? (a) Any time period scheduled to begin...

  5. 40 CFR 270.215 - How are time periods in the requirements in this subpart and my RAP computed?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... requirements in this subpart and my RAP computed? 270.215 Section 270.215 Protection of Environment... HAZARDOUS WASTE PERMIT PROGRAM Remedial Action Plans (RAPs) Operating Under Your Rap § 270.215 How are time periods in the requirements in this subpart and my RAP computed? (a) Any time period scheduled to begin...

  6. 40 CFR 270.215 - How are time periods in the requirements in this subpart and my RAP computed?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... requirements in this subpart and my RAP computed? 270.215 Section 270.215 Protection of Environment... HAZARDOUS WASTE PERMIT PROGRAM Remedial Action Plans (RAPs) Operating Under Your Rap § 270.215 How are time periods in the requirements in this subpart and my RAP computed? (a) Any time period scheduled to begin...

  7. H2 control of discrete-time periodic systems with Markovian jumps and multiplicative noise

    NASA Astrophysics Data System (ADS)

    Ma, Hongji; Jia, Yingmin

    2013-10-01

    This paper addresses the problem of optimal and robust H2 control for discrete-time periodic systems with Markov jump parameters and multiplicative noise. To analyse the system performance in the presence of exogenous random disturbance, an H2 norm is firstly established on the basis of Gramian matrices. Further, under the condition of exact observability, a necessary and sufficient condition is presented for the solvability of H2 optimal control problem by means of a generalised Riccati equation. When the transition probabilities of jump parameter are incompletely measurable, an H2-guaranteed cost norm is exploited and the robust H2 controller is designed through a linear matrix inequality (LMI) optimisation approach. An example of a networked control system is supplied to illustrate the proposed results.

  8. Removing tidal-period variations from time-series data using low-pass digital filters

    USGS Publications Warehouse

    Walters, Roy A.; Heston, Cynthia

    1982-01-01

    Several low-pass, digital filters are examined for their ability to remove tidal Period Variations from a time-series of water surface elevation for San Francisco Bay. The most efficient filter is the one which is applied to the Fourier coefficients of the transformed data, and the filtered data recovered through an inverse transform. The ability of the filters to remove the tidal components increased in the following order: 1) cosine-Lanczos filter, 2) cosine-Lanczos squared filter; 3) Godin filter; and 4) a transform fitter. The Godin fitter is not sufficiently sharp to prevent severe attenuation of 2–3 day variations in surface elevation resulting from weather events.

  9. Efficiency, Power and Period of a model quantum heat engine working in a finite time

    NASA Astrophysics Data System (ADS)

    Bekele, Mulugeta; Dima, Tolasa A.; Alemye, Mekuannent; Chegeno, Warga

    We take a spin-half quantum particle undergoing Carnot type cyclic process in a finite time assisted by two heat reservoirs and an external magnetic field. We find that the power of the heat engine is maximum at a particular period of the cyclic process and efficiency at the maximum power is at least half of the Carnot efficiency. We further apply the Omega-criterion for a figure of merit representing a compromise between useful power and lost power determining the corresponding efficiency for the optimization criterion to be at least three fourth of the Carnot efficiency. The authers are thankful to the International Science programme, IPS, Uppsala, Sweden for their support to our research lab.

  10. Crossing rule for a PT-symmetric two-level time-periodic system

    SciTech Connect

    Moiseyev, Nimrod

    2011-05-15

    For a two-level system in a time-periodic field we show that in the non-Hermitian PT case the level crossing is of two quasistationary states that have the same dynamical symmetry property. At the field's parameters where the two levels which have the same dynamical symmetry cross, the corresponding quasienergy states coalesce and a self-orthogonal state is obtained. This situation is very different from the Hermitian case where a crossing of two quasienergy levels happens only when the corresponding two quasistationary states have different dynamical symmetry properties and, unlike the situation in the non-Hermitian case, the spectrum remains complete also when the two levels cross.

  11. Atmospheric CO2 and climate on millennial time scales during the last glacial period.

    PubMed

    Ahn, Jinho; Brook, Edward J

    2008-10-03

    Reconstructions of ancient atmospheric carbon dioxide (CO2) variations help us better understand how the global carbon cycle and climate are linked. We compared CO2 variations on millennial time scales between 20,000 and 90,000 years ago with an Antarctic temperature proxy and records of abrupt climate change in the Northern Hemisphere. CO2 concentration and Antarctic temperature were positively correlated over millennial-scale climate cycles, implying a strong connection to Southern Ocean processes. Evidence from marine sediment proxies indicates that CO2 concentration rose most rapidly when North Atlantic Deep Water shoaled and stratification in the Southern Ocean was reduced. These increases in CO2 concentration occurred during stadial (cold) periods in the Northern Hemisphere, several thousand years before abrupt warming events in Greenland.

  12. Ordering of small particles in one-dimensional coherent structures by time-periodic flows.

    PubMed

    Pushkin, D O; Melnikov, D E; Shevtsova, V M

    2011-06-10

    Small particles transported by a fluid medium do not necessarily have to follow the flow. We show that for a wide class of time-periodic incompressible flows inertial particles have a tendency to spontaneously align in one-dimensional dynamic coherent structures. This effect may take place for particles so small that often they would be expected to behave as passive tracers and be used in PIV measurement technique. We link the particle tendency to form one-dimensional structures to the nonlinear phenomenon of phase locking. We propose that this general mechanism is, in particular, responsible for the enigmatic formation of the "particle accumulation structures" discovered experimentally in thermocapillary flows more than a decade ago and unexplained until now.

  13. Controllability discrepancy and irreducibility/reducibility of Floquet factorisations in linear continuous-time periodic systems

    NASA Astrophysics Data System (ADS)

    Zhou, Jun; Lu, Xinbiao; Qian, Huimin

    2016-09-01

    The paper reports interesting but unnoticed facts about irreducibility (resp., reducibility) of Flouqet factorisations and their harmonic implication in term of controllability in finite-dimensional linear continuous-time periodic (FDLCP) systems. Reducibility and irreducibility are attributed to matrix logarithm algorithms during computing Floquet factorisations in FDLCP systems, which are a pair of essential features but remain unnoticed in the Floquet theory so far. The study reveals that reducible Floquet factorisations may bring in harmonic waves variance into the Fourier analysis of FDLCP systems that in turn may alter our interpretation of controllability when the Floquet factors are used separately during controllability testing; namely, controllability interpretation discrepancy (or simply, controllability discrepancy) may occur and must be examined whenever reducible Floquet factorisations are involved. On the contrary, when irreducible Floquet factorisations are employed, controllability interpretation discrepancy can be avoided. Examples are included to illustrate such observations.

  14. Behaviour of a thermodynamic model system under time-dependent periodic boundary conditions

    NASA Astrophysics Data System (ADS)

    Berry, R. S.; Disep, F.; Sertorio, L.

    1982-06-01

    A system made of several components is examined which maintains a given volume at a constant temperature Tb or at an almost constant Tb(t), such as in thermal engines. A finite domain D2 is enveloped by a finite domain D1, which is in contact with two thermal baths with time-dependent periodic temperatures Ts(t) and Te(t). The best way to make T2, the temperature field belonging to D2, as close as possible to a predetermine constant is determined using the insertion of controlled energy sources or sinks. The formal approach with zero energy expenditure and the maximization problem are considered. The concepts and properties of free boundary control and deterministic boundary control are examined.

  15. Intercomparison of UT1 measurements during the MERIT campaign period. [Universal Time

    NASA Technical Reports Server (NTRS)

    Spieth, M. A.; Eubanks, T. M.; Steppe, J. A.

    1986-01-01

    Universal time (UT1) measurements obtained using VLBI, lunar laser ranging (LLR), and BIH optical astronomy are compared. The JPL Kalman filter for the earth rotation and the polar motion is utilized to smooth one data set or combine data sets for intercomparison. The differences between raw UT1 data and independently smoothed data are employed to assess the accuracy of the measured series and the sufficiency of the error budget. Systematic errors in periodic signatures and length of day estimates are analyzed. The data reveal that the techniques of LLR and VLBI agree to within their formal errors. It is determined that the residual error for the LLR is too large and the residual error estimated for the BIH data is too small.

  16. Low-thrust roundtrip trajectories to Mars with one-synodic-period repeat time

    NASA Astrophysics Data System (ADS)

    Okutsu, Masataka; Landau, Damon F.; Rogers, Blake A.; Longuski, James M.

    2015-05-01

    Cycler trajectories-both ballistic and powered-are reported in the literature in which there are two-vehicle, three-vehicle, and four-vehicle cases. Such trajectories permit the installation of cycler vehicles which provide safe and comfortable living conditions for human space travel between Earth and Mars during every synodic opportunity. The question the present paper answers is a logical, obvious one: Does a single-vehicle, one-synodic-period cycler exist? The answer is yes: such a trajectory can be flown-but only with a high-power electric propulsion system. In our example, it is found that "stopover" trajectories that spend 30 days in orbit about Earth and 30 days about Mars, and return astronauts to Earth in one synodic period require a 90-t power generator with a power level of 11 MWe. Fortuitously, and in lieu of using chemical propulsion, the high power level of the electric propulsion system would also be effective in hauling the cargo payload via a spiral trajectory about the Earth. But because one synodic period is not enough for the cycler vehicle to fly both the interplanetary trajectories and the Earth-spiral trajectories, we suggest developing two nuclear power generators, which could alternate flying the interplanetary trajectories and the Earth-spiral trajectories. Once these power generators are launched and begin operating in space, the mass requirement in seven subsequent missions (over a period of 15 years beginning in 2022) would be modest at 250-300 metric tons to low-Earth orbit per mission. Thus two cargo launches of NASA's Space Launch System and one crew launch of the Falcon Heavy, for example, would be adequate to maintain support for each consecutive mission. Although we propose developing two sets of electric propulsion systems to account for the Earth-spiral phases, only one vehicle is flown on a heliocentric trajectory at any given time. Thus, our low-thrust stopover cycler with zero encounter velocities falls into a category of a

  17. The clinical picture of late-onset PTSD: a 20-year longitudinal study of Israeli war veterans.

    PubMed

    Horesh, Danny; Solomon, Zahava; Keinan, Giora; Ein-Dor, Tsachi

    2013-08-15

    Delayed-onset posttraumatic stress disorder (PTSD) has been under medico-legal debate for years. Previous studies examining the prevalence and clinical characteristics of delayed-onset PTSD have yielded inconclusive findings. This study prospectively examines the prevalence and clinical picture of late-onset PTSD among Israeli war veterans. It also evaluates whether or not late-onset PTSD erupts after a completely non-symptomatic period. 675 Israeli veterans from the 1982 Lebanon War, with and without antecedent combat stress reaction (CSR), have been assessed 1, 2 and 20 years post-war. They were divided into 4 groups, according to the duration of delay in PTSD onset. Participants completed self-report questionnaires tapping psychopathology, combat exposure and socio-demographics. 16.5% of the veterans suffered from late-onset PTSD. A longer delay in PTSD onset was associated with less severe psychopathology. Also, CSR was associated with a shorter delay in PTSD onset. Finally, the vast majority of veterans already suffered from PTSD symptoms prior to late PTSD onset. Our results offer further validation for the existence of delayed-onset PTSD. Delayed-onset PTSD appears to be a unique sub-type of PTSD, with an attenuated clinical picture. In addition, delayed-onset PTSD may be the result of an incubation process, wherein symptoms already exist prior to PTSD onset.

  18. [A 20-year follow-up study of a sample of 50 pairs of twins with neurotic-psychosomatic disorders].

    PubMed

    Muhs, A; Schepank, H; Manz, R

    1990-01-01

    As part of a research project, examination was made of a sample of 50 pairs of twins (21 pairs of identical twins, 16 pairs of non-identical twins of the same sex, and 13 pairs of male-female twins [n = 100 test persons]) between 1963 and 1969 and again recently after a period of 20 years. The index twins were drawn from among the patients who made use of the services of an out-patient psychotherapeutic clinic, and they were determined to be either psychoneurotic, character neurotic, or psychosomatically ill. The question examined was again one of nature vs. nurture. Identical twins showed a significantly higher similarity with regard to the seriousness of their neuroses and the manifestation of neurotic symptoms than did non-identical twins. Noticeable similarities existed in cases of depressive disturbances, disturbances of oral and aggressive behavior, and disturbances of interpersonal contact. With regard to the influence of variables in the environment, we examined the effect of factors in early childhood on neurotic development. Lack of a reference person, a negative attitude on the part of parents toward the child, etc., frustration within and outside the family have an effect on the manifestation of neuroses and on the course of their development. The influence of early childhood factors on the degree of neurotic disorder is still to be noted in the current point prevalence.

  19. Evaluation of Peri-Implant Bone Response in Implants Retrieved for Fracture After More Than 20 Years of Loading: A Case Series.

    PubMed

    Mangano, Carlo; Piattelli, Adriano; Mortellaro, Carmen; Mangano, Francesco; Perrotti, Vittoria; Iezzi, Giovanna

    2015-08-01

    Analysis of human retrieved dental implants is a useful tool in the evaluation of implant success and failure. More human histological data are needed from samples of long-term implant service. The aim of the present case series was a histological and histomorphometrical evaluation of the peri-implant bone responses in implants retrieved for fracture after more than 20 years loading. The archives of the Implant Retrieval Center of the Department of Medical, Oral and Biotechnological Sciences of the University of Chieti-Pescara, Italy were searched. A total of 5 implants, retrieved after a loading period of more than 20 years, were found: 2 had been retrieved after 20 years, 1 after 22 years, 1 after 25 years, and 1 after 27 years. All these implants were histologically processed. Compact, mature bone in close contact with the implant surface was observed in all specimens, with no gaps or connective tissue at the interface. Bone in different maturation stages was found around some implants. Primarily newly formed bone was observed in proximity of the implant surface, while mature compact bone with many remodeling areas and cement lines were detected in areas distant from the implant. Many primary and secondary osteons were present. Bone to implant contact percentage varied from 37.2% to 76%. In conclusion, histology and histomorphometry showed that even after many years of function, all implants presented more than adequate bone to implant contact and they appeared to be very well integrated in the peri-implant bone.

  20. Diabetes in midlife and cognitive change over 20 years: the Atherosclerosis Risk in Communities Neurocognitive Study

    PubMed Central

    Rawlings, Andreea M.; Sharrett, A. Richey; Schneider, Andrea L.C.; Coresh, Josef; Albert, Marilyn; Couper, David; Griswold, Michael; Gottesman, Rebecca F.; Wagenknecht, Lynne E.; Windham, B. Gwen; Selvin, Elizabeth

    2015-01-01

    Background Type 2 diabetes mellitus is associated with dementia risk, however evidence is limited for possible associations of diabetes and pre-diabetes with cognitive decline. Objective To determine if diabetes in mid-life is associated with 20-year cognitive decline, and to characterize long-term cognitive decline across clinical categories of hemoglobin A1c (HbA1c). Design Prospective cohort. Setting The community-based Atherosclerosis Risk in Communities (ARIC) Study. Participants 13351 black and white adults aged 48-67 years at baseline (1990-1992). Measurements Diabetes was defined by self-report of physician diagnosis or medication use or HbA1c≥6.5%. Undiagnosed diabetes, pre-diabetes, and glucose control in persons with diagnosed diabetes were defined using clinical categories of HbA1c. Delayed Word Recall, Digit Symbol Substitution, and Word Fluency tests were used to assess cognitive performance, and were summarized using a global Z-score. Results Diabetes in midlife was associated with significantly greater cognitive decline over 20 years (adjusted global Z-score difference=-0.15, 95% CI:-0.22,-0.08), representing a 19% greater decline than those without diabetes. Cognitive decline was significantly greater among persons with pre-diabetes (HbA1c 5.7-6.4%) than those without diabetes and HbA1c<5.7%. Participants with poorly controlled diabetes (HbA1c≥7.0%) had a larger decline compared to persons whose diabetes was controlled (adjusted global Z-score difference=-0.16,p-value=0.071). Longer duration of diabetes was also associated with greater late-life cognitive decline (p-value-for-trend=<0.001). No significant differences in the rates of declines were seen in whites compared to blacks (p-value-for-interaction=0.4357). Limitations Single measurement of HbA1c at baseline, only one test to per cognitive domain, potential geographic confounding of race comparisons. Conclusions These findings suggest that diabetes prevention and glucose control in

  1. Estimating interevent time distributions from finite observation periods in communication networks

    NASA Astrophysics Data System (ADS)

    Kivelä, Mikko; Porter, Mason A.

    2015-11-01

    A diverse variety of processes—including recurrent disease episodes, neuron firing, and communication patterns among humans—can be described using interevent time (IET) distributions. Many such processes are ongoing, although event sequences are only available during a finite observation window. Because the observation time window is more likely to begin or end during long IETs than during short ones, the analysis of such data is susceptible to a bias induced by the finite observation period. In this paper, we illustrate how this length bias is born and how it can be corrected without assuming any particular shape for the IET distribution. To do this, we model event sequences using stationary renewal processes, and we formulate simple heuristics for determining the severity of the bias. To illustrate our results, we focus on the example of empirical communication networks, which are temporal networks that are constructed from communication events. The IET distributions of such systems guide efforts to build models of human behavior, and the variance of IETs is very important for estimating the spreading rate of information in networks of temporal interactions. We analyze several well-known data sets from the literature, and we find that the resulting bias can lead to systematic underestimates of the variance in the IET distributions and that correcting for the bias can lead to qualitatively different results for the tails of the IET distributions.

  2. Estimating interevent time distributions from finite observation periods in communication networks.

    PubMed

    Kivelä, Mikko; Porter, Mason A

    2015-11-01

    A diverse variety of processes-including recurrent disease episodes, neuron firing, and communication patterns among humans-can be described using interevent time (IET) distributions. Many such processes are ongoing, although event sequences are only available during a finite observation window. Because the observation time window is more likely to begin or end during long IETs than during short ones, the analysis of such data is susceptible to a bias induced by the finite observation period. In this paper, we illustrate how this length bias is born and how it can be corrected without assuming any particular shape for the IET distribution. To do this, we model event sequences using stationary renewal processes, and we formulate simple heuristics for determining the severity of the bias. To illustrate our results, we focus on the example of empirical communication networks, which are temporal networks that are constructed from communication events. The IET distributions of such systems guide efforts to build models of human behavior, and the variance of IETs is very important for estimating the spreading rate of information in networks of temporal interactions. We analyze several well-known data sets from the literature, and we find that the resulting bias can lead to systematic underestimates of the variance in the IET distributions and that correcting for the bias can lead to qualitatively different results for the tails of the IET distributions.

  3. Growth mechanism of photoreduced silver nanostructures on periodically proton exchanged lithium niobate: Time and concentration dependence

    NASA Astrophysics Data System (ADS)

    Craig Carville, N.; Manzo, Michele; Denning, Denise; Gallo, Katia; Rodriguez, Brian J.

    2013-05-01

    Photodeposition of metallic nanostructures onto ferroelectric surfaces, which have been chemically patterned using a proton exchange process, has recently been demonstrated. By varying the molar concentration of the AgNO3 solution and the illumination time, one can determine the initial nucleation sites, control the rate of nucleation and the height of silver nanostructures formed, and study the mechanisms by which these processes occurs. The nanoparticles are found to deposit preferentially in the boundary between ferroelectric and proton exchanged regions, in an area proton exchanged via lateral diffusion under the masking layer used for chemical patterning, consistent with our previous results. Using a short illumination time (3 min), we are able to determine that the initial nucleation of the silver nanostructure, having a width of 0.17 ± 0.02 μm and a height of 1.61 ± 0.98 nm, occurs near the edge of the reactive ion etched area within this lateral diffusion region. Over longer illumination times (15 min), we find that the silver deposition has spread to a width of 1.29 ± 0.06 μm, extending across the entire lateral diffusion region. We report that at a high molar concentration of AgNO3 (10-2 M), the amount of silver deposition for 5 min UV illumination is greater (2.88 ± 0.58 nm) compared to that at low (10-4 M) concentrations (0.78 ± 0.35 nm), however, this is not the case for longer time periods. With increasing illumination time (15 min), experiments at 10-4 M had greater overall deposition, 6.90 ± 1.52 nm, compared to 4.50 ± 0.76 nm at 10-2 M. For longer exposure times (30 min) at 10-2 M, the nanostructure height is 4.72 ± 0.59 nm, suggesting a saturation in the nanostructure height. The results are discussed in terms of the electric double layer that forms at the crystal surface. There is an order of magnitude difference between the Debye lengths for 10-2 and 10-4 M solutions, i.e., 3.04 vs. 30.40 nm, which suggests the Debye length plays a

  4. Almost periodic solutions for a memristor-based neural networks with leakage, time-varying and distributed delays.

    PubMed

    Jiang, Ping; Zeng, Zhigang; Chen, Jiejie

    2015-08-01

    In this paper, we study the existence and global exponential stability of almost periodic solution for memristor-based neural networks with leakage, time-varying and distributed delays. Using a new Lyapunov function method, we prove that this delayed neural network has a unique almost periodic solution, which is globally exponentially stable. Moreover, the obtained conclusion on the almost periodic solution is applied to prove the existence and stability of periodic solution (or equilibrium point) for this delayed neural network with periodic coefficients (or constant coefficients).

  5. Research on laser protection: an overview of 20 years of activities at Fraunhofer IOSB

    NASA Astrophysics Data System (ADS)

    Ritt, G.; Walter, D.; Eberle, B.

    2013-10-01

    Since the advent of the laser in 1960, the protection of human eyes and sensors against intended or unintended damage by laser radiation is a hot research topic. As long as the parameters of a laser source such as the wavelength and the output power are known, adequate laser safety can be ensured simply by utilizing conventional laser protection filters which are based on absorption or interference effects. This is typically the case in cooperative environments like a laboratory or industrial facilities. A very different situation prevails in military defense or civil security. There, the parameters of encountering laser threats are usually unknown. Protection measures, helping against all types of laser threats, are the long desired objective of countless research activities. The biggest challenge in finding an effective measure arises from single laser pulses of unknown wavelength. The problem demands for a passive protection concept and may be based for example on intensity dependent effects. Moreover, the requested solutions shall comprise add-on possibilities like thin films to be put on existing optics, windshields or glasses. Unfortunately, such an all-embracing solution is still far out of reach. The Fraunhofer IOSB has been working on the evaluation and development of non-conventional laser protection methods for more than 20 years. An overview of the past and present research activities shall be presented, comprising protection measures against laser damaging and laser dazzling.

  6. Cre-Lox Neurogenetics: 20 Years of Versatile Applications in Brain Research and Counting…

    PubMed Central

    Tsien, Joe Z.

    2016-01-01

    Defining and manipulating specific neurons in the brain has garnered enormous interest in recent years, because such an approach is now widely recognized as crucial for deepening our understanding of how the brain works. When I started exploring the Cre-loxP recombination for brain research in the early 1990s, it was written off as a dead-end project by a young fool. Yet over the past 20 years, Cre-lox recombination-mediated neurogenetics has emerged as one of the most powerful and versatile technology platforms for cell-specific gene knockouts, transgenic overexpression, Brainbow imaging, neural pathway tracing with retrovirus and CLARITY, chemical genetics, and optogenetics. Its popularity and greater utility in neuroscience research is also largely thanks to the NIH’s bold Blueprint for Neuroscience Research Initiative to launch several Cre-driver resource projects, as well as individual laboratories and private research organizations. With newly-discovered, genetically-encoded molecules that are capable of responding to sonar and magnetic stimulation, for sonogenetics or magnetogenetics, respectively, or detecting rapid voltage changes in neurons, Cre-lox neurogenetics will continue to aid brain research for years to come. PMID:26925095

  7. How have researchers studied multiracial populations: A content and methodological review of 20 years of research

    PubMed Central

    Charmaraman, Linda; Woo, Meghan; Quach, Ashley; Erkut, Sumru

    2014-01-01

    The U. S. Census shows that the racial-ethnic make-up of over 9 million people (2.9% of the total population) who self-identified as multiracial is extremely diverse. Each multiracial subgroup has unique social and political histories that may lead to distinct societal perceptions, economic situations, and health outcomes. Despite the increasing academic and media interest in multiracial individuals, there are methodological and definitional challenges in studying the population resulting in conflicting representations in the literature. This content and methods review of articles on multiracial populations provides a comprehensive understanding of which multiracial populations have been included in research and how they have been studied both to recognize the emerging research and to identify gaps for guiding future research on this complex but increasingly visible population. We examine 125 U.S.-based peer-reviewed journal articles published over the past 20 years (1990–2009) containing 133 separate studies focused on multiracial individuals from primarily the fields of psychology, sociology, social work, education, and public health. Findings include (a) descriptive data regarding the sampling strategies, methodologies, and demographic characteristics of studies, including which multiracial subgroups are most studied, gender, age range, region of country, socioeconomic status; (b) major thematic trends in research topics concerning multiracial populations; (c) implications and recommendations for future studies. PMID:25045946

  8. Responses of high-altitude graminoids and soil fungi to 20 years of experimental warming.

    PubMed

    Rudgers, Jennifer A; Kivlin, Stephanie N; Whitney, Kenneth D; Price, Mary V; Waser, Nickolas M; Harte, John

    2014-07-01

    High-elevation ecosystems are expected to be particularly sensitive to climate warming because cold temperatures constrain biological processes. Deeper understanding of the consequences of climate change will come from studies that consider not only the direct effects of temperature on individual species, but also the indirect effects of altered species interactions. Here we show that 20 years of experimental warming has changed the species composition of graminoid (grass and sedge) assemblages in a subalpine meadow of the Rocky Mountains, USA, by increasing the frequency of sedges and reducing the frequency of grasses. Because sedges typically have weak interactions with mycorrhizal fungi relative to grasses, lowered abundances of arbuscular mycorrhizal (AM) fungi or other root-inhabiting fungi could underlie warming-induced shifts in plant species composition. However, warming increased root colonization by AM fungi for two grass species, possibly because AM fungi can enhance plant water uptake when soils are dried by experimental warming. Warming had no effect on AM fungal colonization of three other graminoids. Increased AM fungal colonization of the dominant shrub Artemisia tridentata provided further grounds for rejecting the hypothesis that reduced AM fungi caused the shift from grasses to sedges. Non-AM fungi (including dark septate endophytes) also showed general increases with warming. Our results demonstrate that lumping grasses and sedges when characterizing plant community responses can mask significant shifts in the responses of primary producers, and their symbiotic fungi, to climate change.

  9. Rhabdomyolysis and Cardiomyopathy in a 20-Year-Old Patient with CPT II Deficiency

    PubMed Central

    Vavlukis, M.; Eftimov, A.; Zafirovska, P.; Caparovska, E.; Pocesta, B.; Kedev, S.; Dimovski, A. J.

    2014-01-01

    Aim. To raise the awareness of adult-onset carnitite palmitoyltransferase II deficiency (CPT II) by describing clinical, biochemical, and genetic features of the disease occurring in early adulthood. Method. Review of the case characteristics and literature review. Results. We report on a 20-year-old man presenting with dyspnea, fatigue, fever, and myoglobinuria. This was the second episode with such symptoms (the previous one being three years earlier). The symptoms occurred after intense physical work, followed by a viral infection resulting in fever treated with NSAIDs. Massive rhabdomyolysis was diagnosed, resulting in acute renal failure necessitating plasmapheresis and hemodialysis, acute hepatic lesion, and respiratory insufficiency. Additionally, our patient had cardiomyopathy with volume overload. After a detailed workup, CPT II deficiency was suspected. We did a sequencing analysis for exons 1, 3, and 4 of the CPT II gene and found that the patient was homozygote for Ser 113 Leu mutation in exon 3 of the CPT II gene. The patient recovery was complete except for the cardiomiopathy with mildly impaired systolic function. Conclusion. Whenever a patient suffers recurrent episodes of myalgia, followed by myoglobinuria due to rhabdomyolysis, we should always consider the possibility of this rare condition. The definitive diagnose of this condition is achieved by genetic testing. PMID:24563797

  10. Ability of Oral and Maxillofacial Surgery Residents in Diagnosing Jaw Cysts: A Retrospective 20 Years Study

    PubMed Central

    Mohajerani, Hassan; Esmaeelinejad, Mohammad

    2016-01-01

    Introduction Diagnosis of odontogenic cysts despite of their benign nature is a critical and challenging problem especially among undergraduate and postgraduate students. Aim This study aimed to evaluate the capability of oral and maxillofacial surgery residents in diagnosing odontogenic cysts. Materials and Methods This cross-sectional study was executed on 312 patient records over the past 20 years since October 1995 till December 2014 in Taleghani Hospital, Tehran, Iran. All recorded data was based on 2005 World Health Organization (WHO) classifications. The differential diagnosis was made by 65 residents based on clinical and paraclinical evaluations established in the charts. Differential diagnoses made by the residents were compared to the histopathological examination as the gold standard for identifying the nature of the cysts. Weighted kappa test was used to show the degree of agreement. Results Data extracted from 312 records were analyzed. The mean age of examined patients was 27.6 years. The accuracy of diagnosis among the residents was moderate (kw=0.5). The diagnosis made by the residents was significantly related to the radiographic view of the cysts (p<0.05). The residents were able to identify odontogenic keratocysts and dentigerous cysts in most cases. Conclusion There are several factors associated with the occurrence of pathologic odontogenic cysts which could help either the clinician or the pathologist in diagnosing the odontogenic cysts of the jaws. The surgeons should consider these related factors before the final diagnosis and choosing the appropriate treatment plan. PMID:28209002

  11. A 20-Year-Old Retained Surgical Gauze Mimicking a Spinal Tumor: A Case Report

    PubMed Central

    Lee, Sungjoon; Kim, Bomi; Kim, Jung Soo

    2016-01-01

    A 79-year-old man visited our clinic complaining of lower back and left leg radiating pain that began 1 month prior to his presentation. He underwent surgery for lumbar disc herniation 20 years ago at another hospital. Magnetic resonance imaging revealed left-sided foraminal stenosis at L4-5. In addition, a paraspinal mass occupying the L4 spinous process and left lamina was observed. We subsequently performed an L4-5 decompression and fusion. During the operation, retained surgical gauze with granulation tissue was found. The term gossypiboma is used to define a mass lesion consisting of retained surgical gauzes and an adjacent foreign body reaction. Gossypibomas are uncommon in the paraspinal area and are mostly asymptomatic in chronic cases. Because there are no specific clinical or radiological signs, they can be confused with other tumorous conditions. Gossypibomas should be included in the differential diagnosis of paraspinal soft-tissue masses detected in patients with a history of prior spinal surgery. PMID:27799998

  12. Cystic lesions of the adrenal gland: our experience over the last 20 years.

    PubMed

    Sebastiano, Christopher; Zhao, Xiangrong; Deng, Fang-Ming; Das, Kasturi

    2013-09-01

    Cystic lesions of the adrenal gland are uncommon, often presenting with nonspecific clinical and radiologic findings, and are thus underrecognized. They are occasionally associated with malignant neoplasms, which can greatly mimic benign lesions and carry detrimental clinical consequences if misdiagnosed. Here we present our 20-year experience (1992-2012) with these lesions at an academic medical center. Among more than 4500 adrenal gland specimens, 31 cases of adrenal lesions with a predominant cystic component were identified in 30 patients with an age range of 34 to 86 years (median, 55.5 years) and a male/female ratio of 13:17. Macroscopic descriptions, available histologic and immunostain slides, and available radiologic records were reviewed for all included cases. Radiologic studies and gross examination correlated well, and hemorrhage (26 cases; 84%) and encapsulation (25 cases; 81%) appeared to be nonspecific radiologic/gross features shared across histologic subtypes. Microscopic review identified 12 cases (39%) of pseudocysts, 2 cases (6%) of endothelium-derived cysts, and 17 cases (55%) of epithelium-derived cysts. Among these 31 cystic adrenal lesions, 2 cases (6%) were malignant neoplasms (1 epithelioid angiosarcoma, 1 adrenocortical carcinoma). Radiologic impression and histopathologic diagnosis were concordant in 11 (73%) of the 15 cases for which radiologic records were available. This study represents the second largest case series to date on cystic adrenal lesions and presents a comprehensive review on their demographic, clinical, radiologic, and gross and microscopic pathologic features, as well as their differential diagnoses.

  13. Trends in RCT nursing research over 20 years: mind the gap.

    PubMed

    Baldi, Ileana; Dal Lago, Elisa; De Bardi, Sara; Sartor, Giada; Soriani, Nicola; Zanotti, Renzo; Gregori, Dario

    Randomised controlled trial (RCT) literature plays a fundamental role in informing evidence-based medicine and nursing. This paper aims to track geographical and temporal trends in the publication of RCTs in nursing over the past 20 years by means of a bibliometric analysis. The PubMed database was searched for articles published from 1 January 1991 to 31 October 2011 and satisfying this search strategy: nursing [MeSH Terms] AND (RCT OR trial* OR 'experimental study' OR randomised OR randomisation) AND (English[lang]). Abstracts were reviewed to assess whether they met the criteria for an RCT. A manual search of information on country of origin was carried out and Journal Citation Reports® was used to allocate journals to subject areas. RCT methodology is increasingly drawing the attention of nursing researchers worldwide. However, there is a large disparity in research productivity, at least in terms of number of published RCTs in the English language and listed on PubMed, between the most productive continents, North America and Europe, and the others.

  14. Progress on obesity prevention over 20 years in Australia and New Zealand.

    PubMed

    Swinburn, B; Wood, A

    2013-11-01

    The lessons learned from over 20 years of obesity prevention efforts in Australia and New Zealand are presented. The obesity epidemic started in the 1980s but poor monitoring systems meant the rise in obesity prevalence initially went undetected. In the 1990 s, experts started advocating for government action; however, it was the rapid increase in media reports on obesity in the early 2000s which created the pressure for action. Several, comprehensive reports produced some programme investment but no regulatory policies were implemented. The powerful food industry lobby ensured this lack of policies on front-of-pack food labelling, restrictions on unhealthy food marketing to children, or taxes on unhealthy foods. The New Zealand government even backpedalled by rescinding healthy school food guidelines and withdrawing funding for the comprehensive national obesity strategy. In 2007, Australian Governments started a major long term-investment in preventive health in order to improve economic productivity. Other positive initiatives, especially in Australia, were: the establishment of several advocacy organizations; successful, long-term, whole-of-community projects reducing childhood obesity; a national knowledge exchange system for practitioners; and some innovative programmes and social marketing. However, despite multiple reports and strong advocacy, key recommended regulatory policies remain unimplemented, largely due to the private sector interests dominating public policy development.

  15. The problem of pattern and scale in ecology: what have we learned in 20 years?

    PubMed

    Chave, Jérôme

    2013-05-01

    Over the past 20 years, major advances have clarified how ecological patterns inform theory, and how in turn theory informs applied ecology. Also, there has been an increased recognition that the problem of scale at which ecological processes should be considered is critical if we are to produce general predictions. Ecological dynamics is always stochastic at small scales, but variability is conditional on the scale of description. The radical changes in the scope and aims of ecology over the past decades reflect in part the need to address pressing societal issues of environmental change. Technological advances in molecular biology, global positioning, sensing instrumentation and computational power should not be overlooked as an explanation for these radical changes. However, I argue that conceptual unification across ecology, genetics, evolution and physiology has fostered even more fertile questions. We are moving away from the view that evolution is played in a fixed ecological theatre: the theatre is being rapidly and relentlessly redesigned by the players themselves. The maintenance of ecosystem functions depends on shifts in species assemblages and on cellular metabolism, not only on flows of energy and matter. These findings have far reaching implications for our understanding of how ecosystem function and biodiversity will withstand (or not) environmental changes in the 21st century.

  16. Black and White Chains of Risk for Hospitalization Over 20 Years*

    PubMed Central

    FERRARO, KENNETH F.; SHIPPEE, TETYANA PYLYPIV

    2009-01-01

    Drawing from the life course perspective, racial disparities in hospitalization are considered in light of a chain of risk. We ask whether race influences admission to, length of stay in, and mortality following hospitalization. Analyses address these questions with data from a national longitudinal sample of adults to assess racial disparities in the hospitalization experience (n = 6,833). Survey data were merged with hospital records abstracted over 20 years of observation. Multivariate analyses revealed that there were no racial differences in admission, but that black adults generally had longer stays. When isolating each stay prospectively, black adults had longer stays during the first, third, and fourth hospitalizations. Post-hospital mortality after the first stay was also higher for black adults than for their white counterparts, even after controlling for morbidity and status resources. The findings suggest that the racial disparities in hospital length of stay and mortality are explained by the cumulative effects of social and health inequalities over the life course. PMID:18649502

  17. A 20 Year Lifecycle Study for Launch Facilities at the Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Kolody, Mark R.; Li. Wenyan; Hintze, Paul E.; Calle, Luz-Marina

    2009-01-01

    The lifecycle cost analysis was based on corrosion costs for the Kennedy Space Center's Launch Complexes and Mobile Launch Platforms. The first step in the study involved identifying the relevant assets that would be included. Secondly, the identification and collection of the corrosion control cost data for the selected assets was completed. Corrosion control costs were separated into four categories. The sources of cost included the NASA labor for civil servant personnel directly involved in overseeing and managing corrosion control of the assets, United Space Alliance (USA) contractual requirements for performing planned corrosion control tasks, USA performance of unplanned corrosion control tasks, and Testing and Development. Corrosion control operations performed under USA contractual requirements were the most significant contributors to the total cost of corrosion. The operations include the inspection of the pad, routine maintenance of the pad, medium and large scale blasting and repainting activities, and the repair and replacement of structural metal elements. Cost data was collected from the years between 2001 and 2007. These costs were then extrapolated to future years to calculate the 20 year lifecycle costs.

  18. CT angiography after 20 years: a transformation in cardiovascular disease characterization continues to advance.

    PubMed

    Rubin, Geoffrey D; Leipsic, Jonathon; Joseph Schoepf, U; Fleischmann, Dominik; Napel, Sandy

    2014-06-01

    Through a marriage of spiral computed tomography (CT) and graphical volumetric image processing, CT angiography was born 20 years ago. Fueled by a series of technical innovations in CT and image processing, over the next 5-15 years, CT angiography toppled conventional angiography, the undisputed diagnostic reference standard for vascular disease for the prior 70 years, as the preferred modality for the diagnosis and characterization of most cardiovascular abnormalities. This review recounts the evolution of CT angiography from its development and early challenges to a maturing modality that has provided unique insights into cardiovascular disease characterization and management. Selected clinical challenges, which include acute aortic syndromes, peripheral vascular disease, aortic stent-graft and transcatheter aortic valve assessment, and coronary artery disease, are presented as contrasting examples of how CT angiography is changing our approach to cardiovascular disease diagnosis and management. Finally, the recently introduced capabilities for multispectral imaging, tissue perfusion imaging, and radiation dose reduction through iterative reconstruction are explored with consideration toward the continued refinement and advancement of CT angiography.

  19. Penile curvature: an update for management from 20 years experience in a high volume centre.

    PubMed

    Sasso, Francesco; Vittori, Matteo; D'Addessi, Alessandro; Bassi, Pier Francesco

    2016-09-26

    Our aim was to review the literature and discuss about penile curvature in order to have an update for management after 20 years experience in the field.Penile curvature may be congenital or acquired. Congenital penile curvature is a relatively uncommon condition that may present in late adolescent or early adult life. The incidence is estimated to be 0.6 %. On the other side, acquired penile curvature has an overall prevalence of 0.5-13%. Three main factors seem to increase the risk of developing an acquired penile curvature, often related to Peyronie's disease: penile traumatism, genetic and familiar conditions and a history of diseases of the genital tract. In treating Peyronie's disease, no medical therapy is fully effective, and surgery remains the gold standard in cases of severe deformity and/or erectile disfunction. Peyronie's disease is associated with significant psychological stress for patients and their partners. Appropriate treatment should be individualized and tailored to the patient's goals and expectations. There is not the 'best' surgical technique and outcomes are satisfactory when proper treatment decisions are made.

  20. Successfully breaking a 20-year cycle of hospitalizations with recovery-oriented cognitive therapy for schizophrenia.

    PubMed

    Grant, Paul M; Reisweber, Jarrod; Luther, Lauren; Brinen, Aaron P; Beck, Aaron T

    2014-05-01

    Individuals with severe and persistent schizophrenia can present challenges (e.g., difficulties sustaining motivation and conducting information processing tasks) to the implementation of recovery-oriented care. We present a successful application of recovery-oriented cognitive therapy (CT-R), a fusion of the spirit and principles of the recovery movement with the evidence base and know-how of cognitive therapy, that helped an individual with schizophrenia move along her recovery path by overcoming specific obstacles, including a 20-year cycle of hospitalizations (five per year), daily phone calls to local authorities, threatening and berating "voices," the belief that she would be killed at any moment, and social isolation. Building on strengths, treatment included collaboratively identifying meaningful personal goals that were broken down into successfully accomplishable tasks (e.g., making coffee) that disconfirmed negative beliefs and replaced the phone calling. At the end of treatment and at a 6-month follow-up, the phone calls had ceased, psychosocial functioning and neurocognitive performance had increased, and avolition and positive symptoms had decreased. She was not hospitalized once in 24 months. Results suggest that individuals with schizophrenia have untapped potential for recovery that can be mobilized through individualized, goal-focused psychosocial interventions.

  1. [The Italian Places of Nicholas Green 20 years after his assassination].

    PubMed

    De Santo, Natale Gaspare; Scarabelli, Andrea; Citterio, Franco; De Santo, Luca S; De Rosa, Giusy

    2014-01-01

    Twenty years ago, Nicholas Green, a 7- year-old American boy was shot, while on vacation, on the Autostrada (motorway) Salerno to Reggio Calabria in Italy. His organs, with the consent of his parents, Reg and Maggie, were removed and 7 persons had their lives changed. In Italy in these last 20 years, organ donation has increased powerfully from 6.2 to 18.2 per million population with a peak at 20 in 2006. Reg and Maggie Green, after Nicholas death, started campaigning for organ donation by making full use of the media. Italian justice was efficient and the criminals were imprisoned quickly. With popular enthusiasm, a total of 103 places were dedicated to Nicholas (schools, halls, squares, streets, parks, gardens, private collections), a proof of great appreciation. Teaching organ donation to children, nurses and medical students is a powerful tool to convey the message of organ donation. To prevent opposition to organ removal when brain death occurs as Professor Francesco Casavola says signing for organ donation should be a family decision and laws for organ donation should be updated frequently in order to meet the progress of modernity.

  2. A Developmental Sensitive Period for Spike Timing-Dependent Plasticity in the Retinotectal Projection

    PubMed Central

    Tsui, Jennifer; Schwartz, Neil; Ruthazer, Edward S.

    2010-01-01

    The retinotectal projection in Xenopus laevis has been shown to exhibit correlation-based refinement of both anatomical and functional connectivity during development. Spike timing-dependent plasticity (STDP) is an appealing experimental model for correlation-based synaptic plasticity because, in contrast to plasticity induction paradigms using tetanic stimulation or sustained postsynaptic depolarization, its induction protocol more closely resembles natural physiological activity. In Xenopus tadpoles, where anatomical remodeling has been reported throughout much of the life of the animal, in vivo retinotectal STDP has only been examined under a limited set of experimental conditions. Using perforated-patch recordings of retina-evoked EPSCs in tectal neurons, we confirmed that repeatedly driving a retinotectal EPSP 5–10 ms prior to inducing an action potential in the postsynaptic cell, reliably produced timing-dependent long-term potentiation (t-LTP) of the retinotectal synapse in young wild type tadpoles (stages 41–44). At these stages, retinotectal timing-dependent long-term depression (t-LTD) also could be induced by evoking an EPSP to arrive 5–10 ms after an action potential in the tectal cell. However, retinotectal STDP using this standard protocol was limited to a developmental sensitive period, as we were unable to induce t-LTP or t-LTD after stage 44. Surprisingly, this STDP protocol also failed to induce reliable STDP in albino tadpoles at the early ages when it was effective in wild type pigmented animals. Nonetheless, low-frequency flashes to the eye produced a robust NMDA receptor-dependent retinotectal LTD in stage 47 albino tadpoles, demonstrating that the retinotectal synapse can nonetheless be modified in these animals using different plasticity paradigms. PMID:21423499

  3. The last interglacial period on the Pacific Coast of North America: Timing and paleoclimate

    USGS Publications Warehouse

    Muhs, D.R.; Simmons, K.R.; Kennedy, G.L.; Rockwell, T.K.

    2002-01-01

    New, high-precision U-series ages of solitary corals (Balanophyllia elegans) coupled with molluscan faunal data from marine terraces on the Pacific Coast of North America yield information about the timing and warmth of the last interglacial sea-level highstand. Balanophyllia elegans takes up U in isotopic equilibrium with seawater during growth and shortly after death. Corals from the second terrace on San Clemente Island (offshore southern California), the third terrace on Punta Banda (on the Pacific Coast of northern Baja California), and the Discovery Point Formation on Isla de Guadalupe (in the Pacific Ocean offshore Baja California) date to the peak of the last interglacial period and have U-series ages ranging from ca. 123 to 114 ka. The first terrace on Punta Banda has corals with ages ranging from ca. 83 to 80 ka, which corresponds to a sea-level highstand formed in the late last interglacial period. U-series analyses of corals from the Cayucos terrace (central California) and the Nestor terrace at Point Loma (southern California) show that these fossils have evidence of open-system history, similar to what has been reported by other workers for the same localities. Nevertheless, a model of continuous, secondary U and Th uptake shows that two ages of corals are likely present at these localities, representing the ca. 105 and ca. 120 ka sea-level highstands reported elsewhere. U-series ages of last interglacial corals from the Pacific Coast overlap with, but are on average younger than the ages of corals from Barbados, the Bahamas, and Hawaii. This age difference is explained by the nature of the geomorphic response to sea-level change: fringing or barrier reefs on low-latitude coastlines have an accretionary growth style that keeps pace with rising sea level, whether on a tectonically rising or stable coastline. In contrast, midlatitude, high-energy coastlines are sites of platform cutting during the early part of a sea-level high stand and terrace

  4. Time-Based Measurement of Personal Mite Allergen Bioaerosol Exposure over 24 Hour Periods

    PubMed Central

    Tovey, Euan R.; Liu-Brennan, Damien; Garden, Frances L.; Oliver, Brian G.; Perzanowski, Matthew S.; Marks, Guy B.

    2016-01-01

    Allergic diseases such as asthma and rhinitis are common in many countries. Globally the most common allergen associated with symptoms is produced by house dust mites. Although the bed has often been cited as the main site of exposure to mite allergens, surprisingly this has not yet been directly established by measurement due to a lack of suitable methods. Here we report on the development of novel methods to determine the pattern of personal exposure to mite allergen bioaerosols over 24-hour periods and applied this in a small field study using 10 normal adults. Air was sampled using a miniature time-based air-sampler of in-house design located close to the breathing zone of the participants, co-located with a miniature time-lapse camera. Airborne particles, drawn into the sampler at 2L/min via a narrow slot, were impacted onto the peripheral surface of a disk mounted on the hour-hand of either a 12 or 24 hour clock motor. The impaction surface was either an electret cloth, or an adhesive film; both novel for these purposes. Following a review of the time-lapse images, disks were post-hoc cut into subsamples corresponding to eight predetermined categories of indoor or outdoor location, extracted and analysed for mite allergen Der p 1 by an amplified ELISA. Allergen was detected in 57.2% of the total of 353 subsamples collected during 20 days of sampling. Exposure patterns varied over time. Higher concentrations of airborne mite allergen were typically measured in samples collected from domestic locations in the day and evening. Indoor domestic Der p 1 exposures accounted for 59.5% of total exposure, whereas total in-bed-asleep exposure, which varied 80 fold between individuals, accounted overall for 9.85% of total exposure, suggesting beds are not often the main site of exposure. This study establishes the feasibility of novel methods for determining the time-geography of personal exposure to many bioaerosols and identifies new areas for future technical

  5. Recent improvement in lung cancer screening: a comparison of the results carried out in two different time periods.

    PubMed

    Kitajima, Takuji; Nishii, Kenji; Ueoka, Hiroshi; Shibayama, Takuo; Gemba, Kenichi; Kodani, Tsuyoshi; Kiura, Katsuyuki; Tabata, Masahiro; Hotta, Katsuyuki; Tanimoto, Mitsune; Sobue, Tomotaka

    2006-06-01

    To evaluate recent improvements in lung cancer screening, we compared the results of recently conducted lung cancer screening with those of a previous screening. This study compared the survival of lung cancer patients detected by lung cancer screening conducted between 1976 and 1984 (early period) with that conducted between 1989 and 1997 (late period). Two hundred seventy-six patients with lung cancer were detected in the early period and 541 patients with lung cancer were detected in the late period. The median survival time (late : 49.8 vs. early : 27.8 months) and the 5-year survival rate (late : 47.8 vs. early : 34.8%) of the patients with lung cancer detected in the late period were significantly better than those in the early period (p = 0.0054). Among patients undergoing resection, the proportion of pathological stage I patients in the late period was significantly higher than that in the early period (late : 60.8 vs. early : 54.9%, p = 0.005). Multivariate analysis showed that the screening time period was a significant prognostic factor (hazard ratio = 0.685, 95% confidence interval : 0.563-0.832, p = 0.0002). These results were consistent with the findings of case-control studies of lung cancer screening programs in the late period recently conducted in Japan, which also showed a greater efficacy for screening than for previous case-control studies in the early period.

  6. Virtual surveillance of communicable diseases: a 20-year experience in France.

    PubMed

    Flahault, A; Blanchon, T; Dorléans, Y; Toubiana, L; Vibert, J F; Valleron, A J

    2006-10-01

    Inserm has developed, since 1984, an information system based on a computer network of physicians in France. It allows for constitution of large databases on diseases, with individual description of cases, and to explore some aspects of the mathematical theory of communicable diseases. We developed user-friendly interfaces for remote data entry and GIS tools providing real-time atlas of the epidemiologic situation in any location. The continuous and ongoing surveillance network is constituted of about 1200 sentinel voluntary and unpaid investigators. We studied their motivation, reasons for either withdrawal or compliance using survival analyses. We implemented early warning systems for outbreak detection and for time-space forecasting. We conducted epidemiological surveys for investigating outbreaks. Large available time and space series allowed us to calibrate and explore synchronism of influenza epidemics, to test the assumption of panmixing in susceptibles-infectious-removed type models and to study the role of closing school in influenza morbidity and mortality in elderly. More than 250 000 cases of influenza, 150 000 cases of acute diarrheas, 35,000 patients for whom HIV tests have been prescribed by general practitioners and 25,000 cases of chickenpox have been collected. Detection of regional influenza or acute diarrhea outbreaks and forecasting of epidemic trends three weeks ahead are currently broadcasted to the French media and published on Sentiweb on a weekly basis. Age-cohort-period models assessed field effectiveness of mass immunization strategies against measles and influenza in the country. Case-control studies with more than 1200 sets of cases of acute diarrheas and their matched controls showed the role of calicivirus and rotavirus as probable major causes of gastroenteritis during recurrent widespread outbreaks in winter in France. An age-specific model for chickenpox showed the probable role of children in disease transmission to their

  7. The variations of long time period slow slip events along the Ryukyu subduction zone

    NASA Astrophysics Data System (ADS)

    Tu, Y. T.; Heki, K.

    2014-12-01

    Slow slip events (SSEs) are a type of slow earthquakes that can be observed with Global Positioning System (GPS) networks in the world. Those events are detected on intensely coupled plate boundaries such as Cascadia subduction zone (Dragert et al., 2001), western North America, Mexico (Kostoglodov et al., 2003), Alaska (Ohta et al., 2007) and Tokai and Boso areas (Ozawa et al., 2002, 2003), central Japan and are considered to have relations to large subduction thrust earthquakes. However, in southwestern Ryukyu trench where most of researchers believe that it should be a decoupled plate boundary, SSEs recur regularly and are located at a patch that is as deep as 20 to 40 km (Heki and Kataoka, 2008). For comprehending the characteristics and time variations of SSEs in this area, the GEONET GPS data of 16 years are used in this study. During 1997 to 2014, more than thirty SSEs are identified near Hateruma Island, Ryukyu. The average recurrence interval is calculated to be 6.3 months and release seismic moment is Mw 6.6 on average. However, the values of recurrence interval are not invariable. From 1997 to 2002, interval period of SSEs is 7.5 months, but during 2002 to 2008, the interval period decreases suddenly to 5.5 months. After 2008, the value restores to 7.2 months again. Furthermore, the slip amount of SSEs in this area varies with time. From 1997 to 2002, the slip is 9.5 cm/year; and during 2002 to 2008, the value slightly increases to 10.5 cm/year. However, in 2008 to 2013, the slip drops to 6.6 cm/year, but accord to the trend of cumulative slip, the slip value would increase in 2014. Considering these data, we find the slip values increase conspicuously in 2002 and 2013. Coincidentally, one Mw 7.1 thrust earthquake occurred in 2002 and earthquake swarm activity started in the Okinawa trough approximately 50km north of the SSE patch. In 2013, another earthquake swarm activity occurred in nearly the same area as the 2002 activity. This suggests that the

  8. 20 years of reprocessed Lyapunov Exponents from altimetry available on AVISO+

    NASA Astrophysics Data System (ADS)

    Pujol, Marie-Isabelle; Faugere, Yannice; D'Ovidio, Francesco; Morrow, Rosemary; Bronner, Emilie; Picot, Nicolas

    2015-04-01

    SARAL/AltiKa is able to sample the small mesoscale signal with a noise measurement error never reached in nadir conventional altimetry. The SARAL/AltiKa 1-Hz measurement is used in the SSALTO/DUACS system since July 2013 and largely contributes to the quality of the Level4 merged products. These products, are now widely used to define the surface geostrophic currents and beyond that they are used to provide proxies of (sub-)mesoscale transport fronts via the Lyapunov Exponents (LEs). The LEs are being increasingly used in physical, biogeochemical, and ecological applications, ranging from real-time support to field studies to co-localisation of animal tracking with Lagrangian Coherent Structures. In order to better serve the users need, and in collaboration with different laboratories (LOCEAN and CTOH), the LEs and vectors are computed over the 21 year altimeter period and over the global ocean within the SSALTO/DUACS project. This product provides the position, and intensity, and orientation of fronts induced by the mesoscale eddies and underlining part of sub-mesoscale activity. We present here the LEs that will be available on AVISO+ early 2015.

  9. Estimating return periods of extreme values from relatively short time series of winds

    NASA Astrophysics Data System (ADS)

    Jonasson, Kristjan; Agustsson, Halfdan; Rognvaldsson, Olafur; Arfeuille, Gilles

    2013-04-01

    An important factor for determining the prospect of individual wind farm sites is the frequency of extreme winds at hub height. Here, extreme winds are defined as the value of the highest 10 minutes averaged wind speed with a 50 year return period, i.e. annual exceeding probability of 2% (Rodrigo, 2010). A frequently applied method to estimate winds in the lowest few hundred meters above ground is to extrapolate observed 10-meter winds logarithmically to higher altitudes. Recent study by Drechsel et al. (2012) showed however that this methodology is not as accurate as interpolating simulated results from the global ECMWF numerical weather prediction (NWP) model to the desired height. Observations of persistent low level jets near Colima in SW-Mexico also show that the logarithmic approach can give highly inaccurate results for some regions (Arfeuille et al., 2012). To address these shortcomings of limited, and/or poorly representative, observations and extrapolations of winds one can use NWP models to dynamically scale down relatively coarse resolution atmospheric analysis. In the case of limited computing resources one has typically to make a compromise between spatial resolution and the duration of the simulated period, both of which can limit the quality of the wind farm siting. A common method to estimate maximum winds is to fit an extreme value distribution (e.g. Gumbel, gev or Pareto) to the maximum values of each year of available data, or the tail of these values. If data are only available for a short period, e.g. 10 or 15 years, then this will give a rather inaccurate estimate. It is possible to deal with this problem by utilizing monthly or weekly maxima, but this introduces new problems: seasonal variation, autocorrelation of neighboring values, and increased discrepancy between data and fitted distribution. We introduce a new method to estimate return periods of extreme values of winds at hub height from relatively short time series of winds, simulated

  10. Transient time period analysis of smooth handoffs in mobile IP networks and its application to media streaming

    NASA Astrophysics Data System (ADS)

    Lee, Dongwook; Kim, JongWon

    2003-11-01

    Streaming media applications over mobile IP networks suffer from playback disruptions resulting from handoff blackout period as well as bandwidth fluctuation. To overcome buffer shortage, pre-buffering technique can be adopted where the client stores sufficient amount of stream in advance. However, under the mobile IP handoff that may take up to several seconds, it is extremely difficult to sustain seamless playback. Inaccurate and conservative choice on the required buffering size can waste limited latency budget, resulting in quality degradation. In this paper, we are extending--from smooth handoff to fast handoff of mobile IPv6--the transient time analysis recently proposed to approximate transient time durations, STP (silent time period) and UTP (unstable time period). The approximated time periods are utilized to estimate the required buffering buffer size accurately. Network simulation result evaluted under simplified buffering strategies shows that the proposed scheme can provide appropriate guideline on the buffer parameters and thus can improve seamless streaming.

  11. The circadian clock has transient plasticity of period and is required for timing of nocturnal processes in Arabidopsis.

    PubMed

    Dodd, Antony N; Dalchau, Neil; Gardner, Michael J; Baek, Seong-Jin; Webb, Alex A R

    2014-01-01

    A circadian rhythm matched to the phase and period of the day-night cycle has measurable benefits for land plants. We assessed the contribution of circadian period to the phasing of cellular events with the light : dark cycle. We also investigated the plasticity of circadian period within the Arabidopsis circadian oscillator. We monitored the circadian oscillator in wild-type and circadian period mutants under light : dark cycles of varying total duration. We also investigated changes in oscillator dynamics during and after the transition from light : dark cycles to free running conditions. Under light : dark cycles, dawn and dusk were anticipated differently when the circadian period was not resonant with the environmental period ('T cycle'). Entrainment to T cycles differing from the free-running period caused a short-term alteration in oscillator period. The transient plasticity of period was described by existing mathematical models of the Arabidopsis circadian network. We conclude that a circadian period resonant with the period of the environment is particularly important for anticipation of dawn and the timing of nocturnal events; and there is short-term and transient plasticity of period of the Arabidopsis circadian network.

  12. Global upper mantle structure from long-period differential travel times

    SciTech Connect

    Woodward, R.L.; Masters, G. )

    1991-04-10

    The authors have made over ten thousand measurements of PP-P and SS-S differential travel times from long-period Global Digital Seismograph Network recordings of all events with m{sub b} {ge} 5.5 which occurred during the years 1976 and 1986. The experiments indicate that lower-mantle structure and source-receiver structure can each contribute approximately {plus minus}0.5 s to the measured PP-P residuals so there is considerable signal to be explained. The pattern observed in the PP-P measurements is similar to the pattern observed in the SS-S measurements, with the SS-S residuals 2 to 4 times larger in magnitude. Comparisons of measured residuals to those predicted by the upper-mantle models of Woodhouse and Dziewonski show that the overall patterns are quite similar but the amplitude of the model residuals is roughly a factor of 2 too small. Comparisons with the predictions of a whole-mantle model of Tanimoto again shows that the predicted pattern of residuals is reasonably consistent with the observations but now the predicted residuals are too large by about a factor of 2. They have also binned the measurements according to the tectonic regionalization GTR1 of Jordan and find a qualitative correlation of average residual with tectonic region. In particular, Precambrian shields show a strong anomaly, and there is a correlation of residual size with the age of oceanic crust at the bounce point. For all tectonic regions the ratio of SS-S to PP-P residuals is approximately 2. This ratio is consistent with a thermal origin for the observed signal. Finally, measurements show no compelling evidence for azimuthal anisotroph which might be related to fossil spreading direction or the direction of absolute plate motion.

  13. Generational and Time Period Differences in American Adolescents’ Religious Orientation, 1966–2014

    PubMed Central

    Twenge, Jean M.; Exline, Julie J.; Grubbs, Joshua B.; Sastry, Ramya; Campbell, W. Keith

    2015-01-01

    In four large, nationally representative surveys (N = 11.2 million), American adolescents and emerging adults in the 2010s (Millennials) were significantly less religious than previous generations (Boomers, Generation X) at the same age. The data are from the Monitoring the Future studies of 12th graders (1976–2013), 8th and 10th graders (1991–2013), and the American Freshman survey of entering college students (1966–2014). Although the majority of adolescents and emerging adults are still religiously involved, twice as many 12th graders and college students, and 20%–40% more 8th and 10th graders, never attend religious services. Twice as many 12th graders and entering college students in the 2010s (vs. the 1960s–70s) give their religious affiliation as “none,” as do 40%–50% more 8th and 10th graders. Recent birth cohorts report less approval of religious organizations, are less likely to say that religion is important in their lives, report being less spiritual, and spend less time praying or meditating. Thus, declines in religious orientation reach beyond affiliation to religious participation and religiosity, suggesting a movement toward secularism among a growing minority. The declines are larger among girls, Whites, lower-SES individuals, and in the Northeastern U.S., very small among Blacks, and non-existent among political conservatives. Religious affiliation is lower in years with more income inequality, higher median family income, higher materialism, more positive self-views, and lower social support. Overall, these results suggest that the lower religious orientation of Millennials is due to time period or generation, and not to age. PMID:25962174

  14. Generational and time period differences in American adolescents' religious orientation, 1966-2014.

    PubMed

    Twenge, Jean M; Exline, Julie J; Grubbs, Joshua B; Sastry, Ramya; Campbell, W Keith

    2015-01-01

    In four large, nationally representative surveys (N = 11.2 million), American adolescents and emerging adults in the 2010s (Millennials) were significantly less religious than previous generations (Boomers, Generation X) at the same age. The data are from the Monitoring the Future studies of 12th graders (1976-2013), 8th and 10th graders (1991-2013), and the American Freshman survey of entering college students (1966-2014). Although the majority of adolescents and emerging adults are still religiously involved, twice as many 12th graders and college students, and 20%-40% more 8th and 10th graders, never attend religious services. Twice as many 12th graders and entering college students in the 2010s (vs. the 1960s-70s) give their religious affiliation as "none," as do 40%-50% more 8th and 10th graders. Recent birth cohorts report less approval of religious organizations, are less likely to say that religion is important in their lives, report being less spiritual, and spend less time praying or meditating. Thus, declines in religious orientation reach beyond affiliation to religious participation and religiosity, suggesting a movement toward secularism among a growing minority. The declines are larger among girls, Whites, lower-SES individuals, and in the Northeastern U.S., very small among Blacks, and non-existent among political conservatives. Religious affiliation is lower in years with more income inequality, higher median family income, higher materialism, more positive self-views, and lower social support. Overall, these results suggest that the lower religious orientation of Millennials is due to time period or generation, and not to age.

  15. A simple derivation for amplitude and time period of charged particles in an electrostatic bathtub potential

    NASA Astrophysics Data System (ADS)

    Prathap Reddy, K.

    2016-11-01

    An ‘electrostatic bathtub potential’ is defined and analytical expressions for the time period and amplitude of charged particles in this potential are obtained and compared with simulations. These kinds of potentials are encountered in linear electrostatic ion traps, where the potential along the axis appears like a bathtub. Ion traps are used in basic physics research and mass spectrometry to store ions; these stored ions make oscillatory motion within the confined volume of the trap. Usually these traps are designed and studied using ion optical software, but in this work the bathtub potential is reproduced by making two simple modifications to the harmonic oscillator potential. The addition of a linear ‘k 1|x|’ potential makes the simple harmonic potential curve steeper with a sharper turn at the origin, while the introduction of a finite-length zero potential region at the centre reproduces the flat region of the bathtub curve. This whole exercise of modelling a practical experimental situation in terms of a well-known simple physics problem may generate interest among readers.

  16. Precise timing of the last interglacial period from mass spectrometric determination of thorium-230 in corals.

    PubMed

    Edwards, R L; Chen, J H; Ku, T L; Wasserburg, G J

    1987-06-19

    The development of mass spectrometric techniques for determination of (230)Th abundance has made it possible to reduce analytical errors in (238)U-(234)U-(230)Th dating of corals even with very small samples. Samples of 6 x 10(8) atoms of (230)Th can be measured to an accuracy of +/-3 percent (2sigma) and 3 x 10(10) atoms of (230)Th can be measured to an accuracy of +/-0.2 percent. The time range over which useful age data on corals can be obtained now ranges from about 50 to about 500,000 years. For young corals, this approach may be preferable to (14)C dating. The precision with which the age of a coral can now be determined should make it possible to critically test the Milankovitch hypothesis concerning Pleistocene climate fluctuations. Analyses of a number of corals that grew during the last interglacial period yield ages of 122,000 to 130,000 years. The ages coincide with, or slightly postdate, the summer solar insolation high at 65 degrees N latitude which occurred 128,000 years ago. This supports the idea that changes in Pleistocene climate can be the result of variations in the distribution of solar insolation caused by changes in the geometry of the earth's orbit and rotation axis.

  17. Real-time analysis of arc-induced Long Period Gratings under gamma irradiation

    PubMed Central

    Esposito, Flavio; Ranjan, Rajeev; Stăncălie, Andrei; Sporea, Dan; Neguţ, Daniel; Becherescu, Nicu; Campopiano, Stefania; Iadicicco, Agostino

    2017-01-01

    In this paper, we present a comparative experimental and theoretical study on gamma radiation sensitivity of Long Period Gratings (LPGs), fabricated by electric arc discharge technique, as monitored in three single mode optical fibers supplied by different manufacturers. A real-time measurement of LPGs’ wavelength shift was performed until a total dose of 35 kGy was reached, with average dose rate of 0.18 kGy/h, the irradiation being done at room temperature. In one case, a maximum radiation sensitivity of 1.34 nm/kGy was recorded for doses up to 0.5 kGy. Moreover, by combining experimental results with numerical simulations, it was found that changes occurred in the core refractive index of the irradiated optical fibers up to 2.5 ∙ 10−5. The increase of the core thermo-optic coefficient up to 1.5 ∙ 10−8/°C was observed as well. PMID:28262784

  18. Precise timing of the last interglacial period from mass spectrometric determination of thorium-230 in corals

    SciTech Connect

    Edwards, R.L.; Chen, J.H.; Ku, T.L.; Wasserburg, G.J.

    1987-06-19

    The development of mass spectrometric techniques for determination of STTh abundance has made it possible to reduce analytical errors in STYU-STUU-STTh dating of corals even with very small samples. Samples of 6 x 10Y atoms of STTh can be measured to an accuracy of +/- 3% (2sigma) and 3 x 10 atoms of STTh can be measured to an accuracy of +/- 0.2%. The time range over which useful age data on corals can be obtained now ranges from about 50 to about 500,000 years. For young corals, this approach may be preferable to UC dating. The precision should make it possible to critically test the Milankovitch hypothesis concerning Pleistocene climate fluctuations. Analyses of a number of corals that grew during the last interglacial period yield ages of 122,000 to 130,000 years. The ages coincide with, or slightly postdate, the summer solar insolation high at 65N latitude which occurred 128,000 years ago. This supports the idea that changes in Pleistocene climate can be the result of variations in the distribution of solar insolation caused by changes in the geometry of the earth's orbit and rotation axis.

  19. Real-time analysis of arc-induced Long Period Gratings under gamma irradiation

    NASA Astrophysics Data System (ADS)

    Esposito, Flavio; Ranjan, Rajeev; Stăncălie, Andrei; Sporea, Dan; Neguţ, Daniel; Becherescu, Nicu; Campopiano, Stefania; Iadicicco, Agostino

    2017-03-01

    In this paper, we present a comparative experimental and theoretical study on gamma radiation sensitivity of Long Period Gratings (LPGs), fabricated by electric arc discharge technique, as monitored in three single mode optical fibers supplied by different manufacturers. A real-time measurement of LPGs’ wavelength shift was performed until a total dose of 35 kGy was reached, with average dose rate of 0.18 kGy/h, the irradiation being done at room temperature. In one case, a maximum radiation sensitivity of 1.34 nm/kGy was recorded for doses up to 0.5 kGy. Moreover, by combining experimental results with numerical simulations, it was found that changes occurred in the core refractive index of the irradiated optical fibers up to 2.5 • 10‑5. The increase of the core thermo-optic coefficient up to 1.5 • 10‑8/°C was observed as well.

  20. Mars exploration, Venus swingby and conjunction class mission modes, time period 2000 to 2045

    NASA Technical Reports Server (NTRS)

    Young, A. C.; Mulqueen, J. A.; Skinner, J. E.

    1984-01-01

    Trajectory and mission requirement data are presented for Earth-Mars opposition class and conjunction class round trip stopover mission opportunities available during the time period year 2000 to year 2045. The opposition class mission employs the gravitational field of Venus to accelerate the space vehicle on either the outbound or inbound leg. The gravitational field of Venus was used to reduce the propulsion requirement associated with the opposition class mission. Representative space vehicle systems are sized to compare the initial mass required in low Earth orbit of one mission opportunity with another mission opportunity. The interplanetary space vehicle is made up of the spacecraft and the space vehicle acceleration system. The space vehicle acceleration system consists of three propulsion stages. The first propulsion stage performs the Earth escape maneuver; the second stage brakes the spacecraft and Earth braking stage into the Mars elliptical orbit and effects the escape maneuver from the Mars elliptical orbit. The third propulsion stage brakes the mission module into an elliptical orbit at Earth return. The interplanetary space vehicle was assumed to be assembled in and depart from the space station circular orbit.