Science.gov

Sample records for 3-year time period

  1. Do autistic symptoms persist across time? Evidence of substantial change in symptomatology over a 3-year period in cognitively able children with autism.

    PubMed

    Pellicano, Elizabeth

    2012-03-01

    This study investigated the extent and nature of changes in symptomatology in cognitively able children with autism over a 3-year period. Thirty-seven children diagnosed with an autism spectrum condition involved in an earlier study (M age  =  5 years, 7 months) were followed and reassessed 3 years later (M age  =  8 years, 4 months). Scores on the Social Communication Questionnaire (SCQ; M. Rutter, A. Bailey, & C. Lord, 2003 ) decreased significantly over time in all symptom domains but especially in the social domain, and correlational findings suggested the presence of 2 distinct developmental trajectories-social communication and repetitive behaviors-that interact across time. Furthermore, 7 children (19% of sample) made substantial changes to the extent that they failed to meet criteria on diagnostic instruments (the Autism Diagnostic Observation Schedule-Generic [ADOS-G; C. Lord, M. Rutter, P. C. DiLavore, & S. Risi, 1999 ] and the SCQ) 3 years later. Children showing diagnostic discontinuity were distinguishable from those who fulfilled ADOS-G criteria only in terms of the age at which they began receiving intervention. The presence of a significant proportion of children showing considerable progress over the 3-year period challenges assumptions of diagnostic continuity and highlights the potential long-term benefits of early intervention.

  2. Coincident 1.3-year Periodicities in the ap Geomagnetic Index and the Solar Wind

    NASA Technical Reports Server (NTRS)

    Paularena, K. I.; Szabo, A.; Richardson, J. D.

    1995-01-01

    Recent observations show an approximately 1.3-year period in the speed of the solar wind detected by the IMP 8 and Voyager 2 spacecraft. A similar period is also seen in the north-south (GSE) component of the magnetic field observed by IMP 8. Since both parameters are commonly used as input to models of geomagnetic activity, the 'ap' index (a measure of geomagnetic disturbance) is examined to look for this periodicity. The Lomb-Scargle periodogram method is used on the ap, plasma, and magnetic field data during the 1973-1994 time range. A dynamic FFT periodogram method is also used to analyze the ap data during this time, as well as to look for periods present between 1932 and 1972. A clear 1.3-year periodicity is present in the post-1986 data when the same period is observed in the plasma and field data. The V(2)B(zsm) and V(2)B(s) proxies for geomagnetic activity also show this periodicity. However, the southward (GSM) component of the magnetic field does not have a 1.3-year period, and neither do solar wind or ap data from 1973-1985. This demonstrates that the ap geomagnetic index can act as a proxy for solar wind periodicities at this time scale. Historic ap data are examined, and show that a similar periodicity in ap exists around 1942. Since auroral data show a 1.4-year periodicity, all these similar periods may result from a common underlying solar mechanism.

  3. Living with diabetes—Development of learning patterns over a 3-year period

    PubMed Central

    Kneck, Åsa; Fagerberg, Ingegerd; Eriksson, Lars E.; Lundman, Berit

    2014-01-01

    Background Learning involves acquiring new knowledge and skills, and changing our ways of thinking, acting, and feeling. Learning in relation to living with diabetes is a lifelong process where there is limited knowledge of how it is experienced and established over time. It was considered important to explore how learning was developed over time for persons living with diabetes. Aim The aim of the study was to identify patterns in learning when living with diabetes, from recently being diagnosed, and over a 3-year period. Materials and methods A longitudinal qualitative descriptive design was used. Thirteen participants, with both type I and type II diabetes, were interviewed at three different occasions during a 3-year period. Qualitative content analysis was used in different steps in order to distinguish patterns. Findings Five main patterns of learning were identified. Two of the patterns (I and II) were characterized by gradually becoming comfortable living with diabetes, whereas for one pattern (IV) living with diabetes became gradually more difficult. For pattern V living with diabetes was making only a limited impact on life, whereas for Pattern III there was a constant management of obstacles related to illness. The different patterns in the present study showed common and different ways of learning and using different learning strategies at different timespans. Conclusion The present study showed that duration of illness is not of importance for how far a person has come in his own learning process. A person-centered care is needed to meet the different and changing needs of persons living with diabetes in relation to learning to live with a lifelong illness. PMID:25030359

  4. Twenty years of interplanetary magnetic field variations with periods in the range of 10 days to 3 years

    SciTech Connect

    Szabo, A.; Lepping, R.P.; King, J.H.

    1995-06-01

    Twenty years of interplanetary magnetic field data collected primarily by the IMP-8 spacecraft near Earth has been analyzed by a dynamic periodogram method in search of significant periodicities in the range of 10 days to 3 years. The method has the advantage of detecting variations with time in the periodicities besides determining the power and phase of the dominant variations. It has been found that the well known periodicities near 1 year and 27 days are strongly modulated by the solar cycle. Both of these periodicities are only detected during solar minimum. During solar maximum. a number of unusual variations are observed. Special emphasis will be placed on the recently reported 1.3 year variation in solar wind parameters besides periods in the interplanetary magnetic field near 51, 73 and 154 days. Correlations with solar wind plasma and solar index variations will also be presented.

  5. Twenty years of interplanetary magnetic field variations with periods in the range of 10 days to 3 years

    NASA Technical Reports Server (NTRS)

    Szabo, A.; Lepping, R. P.; King, J. H.

    1995-01-01

    Twenty years of interplanetary magnetic field data collected primarily by the IMP-8 spacecraft near Earth has been analyzed by a dynamic periodogram method in search of significant periodicities in the range of 10 days to 3 years. The method has the advantage of detecting variations with time in the periodicities besides determining the power and phase of the dominant variations. It has been found that the well known periodicities near 1 year and 27 days are strongly modulated by the solar cycle. Both of these periodicities are only detected during solar minimum. During solar maximum. a number of unusual variations are observed. Special emphasis will be placed on the recently reported 1.3 year variation in solar wind parameters besides periods in the interplanetary magnetic field near 51, 73 and 154 days. Correlations with solar wind plasma and solar index variations will also be presented.

  6. Primary prevention in health care employees: a prospective intervention study with a 3-year training period.

    PubMed

    Löffler, Harald; Bruckner, Thomas; Diepgen, Thomas; Effendy, Isaak

    2006-04-01

    Irritant contact dermatitis is a mayor problem in health care employees. Because educational programs have shown convincing success in certain occupations (e.g. in hairdressers), this study investigates the effect of a special training program in health care trainees. 521 trainees from 14 nursing schools in Central Germany were randomly divided in 2 groups, (i) an intervention group with a regular teaching protocol regarding all aspects of primary prevention and (ii) a control group without any further teaching. Morphological changes of the hands, use of hand care creams and knowledge regarding skin care were evaluated regularly during their 3 years lasting training period (1999-2002). In the intervention group, we found at the end of the 3-year training period a significant better skin condition of the hands than in the control group: a 3-year prevalence of morphological skin changes of 66.7% versus 89.3%. The unteached trainees (control group) had an odds ratio (OR) of 4.8 [95% confidential interval (CI): 2.9-7.8] for developing any skin changes on the hands after 3 years. Besides the effect of the teaching, the history of hand dermatitis before the study start was an independent risk factor for development of further hand dermatitis [OR 1.9, 95% CI: 1.0-3.6). Age and sex showed no influence on the skin condition. Atopic constitution had an influence on the development of skin changes only at the evaluation after 18 month. The observed effect in the intervention group may best be explained by different behaviour of the trainees, e.g. the amount of hand washing was reduced, while procedure of hand disinfection remained unchanged compared with the control group. However, the amount of used skin care cream did not differ between the both groups. This study shows that primary prevention of skin disease by regularly teaching during the training period of medical employees can effectively reduce the risk of development of irritant skin changes of the hands. Therefore

  7. Longitudinal association of maternal attempt to lose weight during the postpartum period and child obesity at age 3 years.

    PubMed

    Sonneville, Kendrin R; Rifas-Shiman, Sheryl L; Oken, Emily; Peterson, Karen E; Gortmaker, Steven L; Gillman, Matthew W; Taveras, Elsie M

    2011-10-01

    The effect of maternal attempt to lose weight during the postpartum period on later child weight has not been explored. Among 1,044 mother-infant pairs in Project Viva, we estimated longitudinal associations of maternal attempt to lose weight during the postpartum period with child weight and adiposity at age 3 years and examined differences in associations by type of weight loss strategy used. Using covariate-adjusted linear and logistic regression models, we estimated associations before and after adjusting for maternal weight-related variables including prepregnancy BMI. At 6 months postpartum, 53% mothers were trying to lose weight. At age 3 years, mean (s.d.) child BMI z-score was 0.44 (1.01) and 8.9% of children were obese. Children whose mothers were trying to lose weight at 6 months postpartum had higher BMI z-scores (0.30 (95% confidence interval (CI) 0.18, 0.42)) and were more likely to be obese (3.0 (95% CI 1.6, 5.8)) at 3 years of age. Addition of maternal prepregnancy BMI to the models attenuated but did not eliminate the associations seen for BMI z-score (0.24 (95% CI 0.12, 0.36) and obesity (2.4 (95% CI 1.2, 4.7)). Attempting to lose weight by exercising alone was the only weight loss strategy that consistently predicted higher child BMI z-score (0.36 (95% CI 0.14, 0.58)) and odds of obesity (6.0 (95% CI 2.2, 16.5)) at age 3 years. In conclusion, we observed an association between maternal attempt to lose weight at 6 months postpartum, particularly through exercise alone, measured using a single item and child adiposity at age 3 years. This association should be thoroughly examined in future studies.

  8. Patterns of nonfatal heroin overdose over a 3-year period: findings from the Australian treatment outcome study.

    PubMed

    Darke, Shane; Williamson, Anna; Ross, Joanne; Mills, Katherine L; Havard, Alys; Teesson, Maree

    2007-03-01

    To determine annual patterns and correlates of nonfatal heroin overdose across 3 years, data were analyzed on 387 heroin users recruited for the Australian Treatment Outcome Study (ATOS), interviewed at 12, 24, and 36 months. A heroin overdose across follow-up was reported by 18.6%, and naloxone had been administered to 11.9%. Annual rates of overdose declined between baseline and 12 months and then remained stable. Previous overdose experience was strongly related to subsequent overdose. Those with a history of overdose before ATOS were significantly more likely to overdose during the study period. In particular, there was a strong association between overdose experience in any 1 year and increased overdose risk in the subsequent year. This is the first study to examine long-term annual trends in nonfatal heroin overdose. While overdose rates declined after extensive treatment, substantial proportions continued to overdose in each year, and this was strongly associated with overdose history.

  9. The impact of remedial intervention on 3-year recidivism among first-time DUI offenders in Mississippi.

    PubMed

    Robertson, Angela A; Gardner, Sheena; Xu, Xiaohe; Costello, Humphrey

    2009-09-01

    This study examines the impact of the Mississippi Alcohol Safety Education Program (MASEP), a court-mandated intervention program, on 3-year recidivism rates among first-time DUI offenders (i.e. those convicted of a first offense for driving under the influence of alcohol or another drug). It also examines whether a new version of the curriculum that incorporates activities to enhance motivation for change further ameliorates recidivism. Cox proportional hazard regression models are used to compare recidivism rates among DUI offenders who completed MASEP with those who did not complete or who failed to enroll in the program. Recidivism rates were also compared for MASEP participants across time periods during which curriculum revisions were introduced. The hazard of recidivism was lower for individuals who completed the program than for individuals who did not complete or did not enroll in the program. Recidivism rates were further reduced following the introduction of curriculum revisions. Attendance of court-mandated remedial intervention programs lower subsequent DUI arrests and program content is associated with lower rates.

  10. Occurrence and molecular characterization of Klebsiella pneumoniae ST37 clinical isolates producing plasmid-mediated AmpC recovered over a 3-year period.

    PubMed

    Illiaquer, Marina; Caroff, Nathalie; Bémer, Pascale; Aubin, Guillaume G; Juvin, Marie-Emmanuelle; Lepelletier, Didier; Reynaud, Alain; Corvec, Stéphane

    2012-09-01

    We investigated the clinical and microbiological epidemiology of AmpC plasmidic cephalosporinases (pAmpC) in Klebsiella pneumoniae strains resistant to ceftazidime, during a 3-year period (2007-2009). Among 1505 K. pneumoniae, 7 were pAmpC producers. Molecular characterization revealed the spread of a ST37 strain producing DHA-1 within intensive care units and the diffusion of the same plasmid among unrelated strains.

  11. Review Over a 3-Year Period of European Union Proficiency Tests for Detection of Staphylococcal Enterotoxins in Food Matrices.

    PubMed

    Nia, Yacine; Mutel, Isabelle; Assere, Adrien; Lombard, Bertrand; Auvray, Frederic; Hennekinne, Jacques-Antoine

    2016-04-13

    Staphylococcal food poisoning outbreaks are a major cause of foodborne illnesses in Europe and their notifications have been mandatory since 2005. Even though the European regulation on microbiological criteria for food defines a criterion on staphylococcal enterotoxin (SE) only in cheese and dairy products, European Food Safety Authority (EFSA) data reported that various types of food matrices are involved in staphylococcal food poisoning outbreaks. The European Screening Method (ESM) of European Union Reference Laboratory for Coagulase Positive Staphylococci (EURL CPS) was validated in 2011 for SE detection in food matrices and is currently the official method used for screening purposes in Europe. In this context, EURLCPS is annually organizing Inter-Laboratory Proficiency Testing Trials (ILPT) to evaluate the competency of the European countries' National Reference Laboratories (NRLs) to analyse SE content in food matrices. A total of 31 NRLs representing 93% of European countries participated in these ILPTs. Eight food matrices were used for ILPT over the period 2013-2015, including cheese, freeze-dried cheese, tuna, mackerel, roasted chicken, ready-to-eat food, milk, and pastry. Food samples were spiked with four SE types (i.e., SEA, SEC, SED, and SEE) at various concentrations. Homogeneity and stability studies showed that ILPT samples were both homogeneous and stable. The analysis of results obtained by participants for a total of 155 blank and 620 contaminated samples allowed for evaluation of trueness (>98%) and specificity (100%) of ESM. Further to the validation study of ESM carried out in 2011, these three ILPTs allowed for the assessment of the proficiency of the NRL network and the performance of ESM on a large variety of food matrices and samples. The ILPT design presented here will be helpful for the organization of ILPT on SE detection by NRLs or other expert laboratories.

  12. 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....

  13. 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....

  14. 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....

  15. 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....

  16. Monitoring and source tracking of tetracycline resistance genes in lagoons and groundwater adjacent to swine production facilities over a 3-year period

    USGS Publications Warehouse

    Koike, S.; Krapac, I.G.; Oliver, H.D.; Yannarell, A.C.; Chee-Sanford, J. C.; Aminov, R.I.; Mackie, R.I.

    2007-01-01

    To monitor the dissemination of resistance genes into the environment, we determined the occurrence of tetracycline resistance (Tcr) genes in groundwater underlying two swine confinement operations. Monitoring well networks (16 wells at site A and 6 wells at site C) were established around the lagoons at each facility. Groundwater (n = 124) and lagoon (n = 12) samples were collected from the two sites at six sampling times from 2000 through 2003. Total DNA was extracted, and PCR was used to detect seven Tcr genes [tet(M), tet(O), tet(Q), tet(W), tet(C), tet(H), and tet(Z)]. The concentration of Tcr genes was quantified by real-time quantitative PCR. To confirm the Tcr gene source in groundwater, comparative analysis of tet(W) gene sequences was performed on groundwater and lagoon samples. All seven Tcr genes were continually detected in groundwater during the 3-year monitoring period at both sites. At site A, elevated detection frequency and concentration of Tcr genes were observed in the wells located down-gradient of the lagoon. Comparative analysis of tet(W) sequences revealed that the impacted groundwater contained gene sequences almost identical (99.8% identity) to those in the lagoon, but these genes were not found in background libraries. Novel sequence clusters and unique indigenous resistance gene pools were also found in the groundwater. Thus, antibiotic resistance genes in groundwater are affected by swine manure, but they are also part of the indigenous gene pool. Copyright ?? 2007, American Society for Microbiology. All Rights Reserved.

  17. 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.

  18. 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.

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. Risk for Sleep Disorder Measured during Students' First College Semester May Predict Institutional Retention and Grade Point Average over a 3-Year Period, with Indirect Effects through Self-Efficacy

    ERIC Educational Resources Information Center

    Gaultney, Jane F.

    2016-01-01

    The present study used a validated survey to assess freshmen college students' sleep patterns and risk for sleep disorders and then examined associations with retention and grade point average (GPA) over a 3-year period. Students at risk for a sleep disorder were more likely to leave the institution over the 3-year period, although this…

  5. Case Study: Variation in fatty acid profiles in milk from adjacent organic and conventional dairy farms over a 3-year period

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Measuring the seasonal variability of fatty acids (FAs) in milk improves our understanding of the nutritional and health values of milk. In collaboration with the Rodale Institute, Kutztown, PA, a 3-year study evaluated the seasonal variation of FA profiles of milk obtained from two farms adjacent t...

  6. Water Quality Conditions Monitored at the Corps’ Garrison Project in North Dakota during the 3-Year Period 2003 through 2005

    DTIC Science & Technology

    2006-07-01

    period 2003 through 2005. Collected algae included taxa from the following seven taxonomic Divisions: Bacillariophyta (Diatioms), Chlorophyta (Green... Chlorophyta /Cryptophyta > Cyanobacteria > Pyrrophyta > Chrysophyta >> Euglenophyta. The diatoms were generally the most prevalent algae throughout the...collected at sites L1, L3, L5, and L7 during the period 2003 through 2005. Site Date Biovolume (um3) Bacillariophyta Chlorophyta Chrysophyta

  7. 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

  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. Voice onset time of voiceless bilabial and velar stops in 3-year-old bilingual children and their age-matched monolingual peers

    PubMed Central

    FABIANO-SMITH, LEAH; BUNTA, FERENC

    2013-01-01

    This study investigates aspects of voice onset time (VOT) of voiceless bilabial and velar stops in monolingual and bilingual children. VOT poses a special challenge for bilingual Spanish- and English-speaking children because although this VOT distinction exists in both languages, the values differ for the same contrast across Spanish and English. Twenty-four 3-year-olds participated in this study (8 bilingual Spanish–English, 8 monolingual Spanish and 8 monolingual English). The VOT productions of /p/ and /k/ in syllable-initial stressed singleton position were compared across participants. Non-parametric statistical analyses were performed to examine differences (1) between monolinguals and bilinguals and (2) between English and Spanish. The main findings of the study were that monolingual and bilingual children generally differed on VOT in English, but not in Spanish. No statistically significant differences were found between the Spanish and the English VOT of the bilingual children, but the VOT values did differ significantly for monolingual Spanish-versus monolingual English-speaking participants. Our findings were interpreted in terms of Flege’s Speech Learning Model, finding possible evidence for equivalence classification. PMID:21787142

  10. Voice onset time of voiceless bilabial and velar stops in 3-year-old bilingual children and their age-matched monolingual peers.

    PubMed

    Fabiano-Smith, Leah; Bunta, Ferenc

    2012-02-01

    This study investigates aspects of voice onset time (VOT) of voiceless bilabial and velar stops in monolingual and bilingual children. VOT poses a special challenge for bilingual Spanish- and English-speaking children because although this VOT distinction exists in both languages, the values differ for the same contrast across Spanish and English. Twenty-four 3-year-olds participated in this study (8 bilingual Spanish-English, 8 monolingual Spanish and 8 monolingual English). The VOT productions of /p/ and /k/ in syllable-initial stressed singleton position were compared across participants. Non-parametric statistical analyses were performed to examine differences (1) between monolinguals and bilinguals and (2) between English and Spanish. The main findings of the study were that monolingual and bilingual children generally differed on VOT in English, but not in Spanish. No statistically significant differences were found between the Spanish and the English VOT of the bilingual children, but the VOT values did differ significantly for monolingual Spanish- versus monolingual English-speaking participants. Our findings were interpreted in terms of Flege's Speech Learning Model, finding possible evidence for equivalence classification.

  11. Developmental milestones record - 3 years

    MedlinePlus

    ... years; Growth milestones for children - 3 years; Childhood growth milestones - 3 years; Well child - 3 years ... activities related to your child's interests. Encourage your child to use words to express feelings (rather than acting out).

  12. 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.

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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)...

  18. 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...

  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. 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.

  1. 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…

  2. 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.

  3. 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

  4. 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...

  5. 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...

  6. 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)...

  7. 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....

  8. 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)...

  9. 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)...

  10. 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...

  11. 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...

  12. 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...

  13. The bacteriological quality of retail-level peanut, almond, cashew, hazelnut, brazil, and mixed nut kernels produced in two Australian nut-processing facilities over a period of 3 years.

    PubMed

    Eglezos, Sofroni

    2010-07-01

    An investigation of the bacteriological quality of ready-to-eat peanuts, almonds, cashews, hazelnuts, and brazil nuts processed in two Australian nut-processing facilities was performed over a period of 3 years. A total of 564 ready-to-eat retail packs were analyzed for aerobic plate count (APC), Salmonella, coagulase-positive staphylococci, Listeria monocytogenes, and Escherichia coli. Of these samples, 343 were peanuts, 45 cashews, 42 almonds, 40 brazil nuts, 51 hazelnuts, and 43 were mixed packs containing all five types. There was no Salmonella, E. coli, or coagulase-positive staphylococci detected in any sample. L. monocytogenes was detected in two of the mixed packs after enrichment, but was not detected from samples by an alternate enumeration method (detection limit = 10/g). The APC percentages of positive samples with counts above the detection level of the plating method used (100 CFU/g) for peanuts, almonds, cashews, hazelnuts, brazil nuts, and mixed nuts were 48%, 36%, 62%, 36%, 56%, and 44%, respectively. Of the samples containing more than this detection limit, the means were 2.7, 2.4, 2.4, 2.6, 2.8, and 2.7 log CFU/g, respectively. The maximum APC was 3.9 log CFU/g. The bacteriological quality of roasted peanut, almond, cashew, hazelnut, brazil, and mixed nut kernels processed in Australian facilities does not appear to suggest a public health concern.

  14. A survey of the bacteriological quality of preroasted peanut, almond, cashew, hazelnut, and brazil nut kernels received into three Australian nut-processing facilities over a period of 3 years.

    PubMed

    Eglezos, Sofroni; Huang, Bixing; Stuttard, Ed

    2008-02-01

    There is little information about bacteriological quality of preroasted kernels available in the public domain. An investigation of the bacteriological quality of preroasted peanut, almond, cashew, hazelnut, and Brazil nut kernels received into three Australian nut-processing facilities was performed over a period of 3 years. A total of 836 samples were analyzed for aerobic plate count, and 921 samples for Salmonella and Escherichia coli. The 921 samples included 653 peanut, 100 cashew, 60 almond, 60 Brazil nut, and 48 hazelnut kernels. There was no E. coli detected in any sample. Salmonella subsp. II (Fremantle) was detected in one raw almond sample. The aerobic plate count percentages of positive samples with counts above the detection level of the plating method used (100 CFU/g) for peanuts, almonds, cashews, hazelnuts, and Brazil nuts were 84, 78, 74, 50, and 45%, respectively. Of the samples containing more than this detection limit, the means were 4.5, 4.4, 3.1, 2.5, and 3.8 log CFU/g respectively. Although roasted kernel quality was not within the scope of this survey, raw microbial bioload would be expected to reduce on roasting. The bacteriological quality of preroasted peanut, almond, cashew, hazelnut, and Brazil nut kernels received into nut-processing facilities in Australia does not appear to suggest a public health concern.

  15. Your Child's Development: 3 Years

    MedlinePlus

    ... Feeding Your 1- to 2-Year-Old Your Child’s Development: 3 Years KidsHealth > For Parents > Your Child’s Development: 3 Years A A A Kids this age ... but certain signs could indicate a delay in development. Talk to your doctor if your child: doesn't speak, or can't speak in ...

  16. Your Child's Development: 3 Years

    MedlinePlus

    ... Feeding Your 1- to 2-Year-Old Your Child’s Development: 3 Years KidsHealth > For Parents > Your Child’s Development: 3 Years Print A A A en español ... but certain signs could indicate a delay in development. Talk to your doctor if your child: doesn't speak, or can't speak in ...

  17. 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.

  18. 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.

  19. Clinical evaluation of 860 anterior and posterior lithium disilicate restorations: retrospective study with a mean follow-up of 3 years and a maximum observational period of 6 years.

    PubMed

    Fabbri, Giacomo; Zarone, Fernando; Dellificorelli, Gianluca; Cannistraro, Giorgio; De Lorenzi, Marco; Mosca, Alberto; Sorrentino, Roberto

    2014-01-01

    This study aimed to assess the clinical performance of lithium disilicate restorations supported by natural teeth or implants. Eight hundred sixty lithium disilicate adhesive restorations, including crowns on natural teeth and implant abutments, veneers, and onlays, were made in 312 patients. Parafunctional patients were included, but subjects with uncontrolled periodontitis and gingival inflammation were excluded. Veneers up to 0.5 mm thick were luted with flowable composite resin or light curing cements, while dual-curing composite systems were used with veneers up to 0.8 mm thick. Onlays up to 2 mm in thickness were luted with flowable composite resins or dual-curing composite cements. Crowns up to 1 mm in thickness were cemented with self-adhesive or dual-curing resin cements. The observational period ranged from 12 to 72 months, with a mean follow-up of 3 years. The mechanical and esthetic outcomes of the restorations were evaluated according to the modified California Dental Association (CDA) criteria. Data were analyzed with descriptive statistics. Twenty-six mechanical complications were observed: 17 porcelain chippings, 5 fractures, and 4 losses of retention. Structural drawbacks occurred mainly in posterior segments, and monolithic restorations showed the lowest number of mechanical complications. The clinical ratings of the successful restorations, both monolithic and layered, were satisfactory according to the modified CDA criteria for color match, porcelain surface, and marginal integrity. The cumulative survival rates of lithium disilicate restorations ranged from 95.46% to 100%, while cumulative success rates ranged from 95.39% to 100%. All restorations recorded very high survival and success rates. The use of lithium disilicate restorations in fixed prosthodontics proved to be effective and reliable in the short- and medium-term.

  20. 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

  1. 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.

  2. Persistence and Attainment of 2011-12 First-Time Postsecondary Students after 3 Years. First Look. NCES 2016-401

    ERIC Educational Resources Information Center

    Ifill, Nicole; Radford, Alexandria Walton; Wu, Joanna; Cataldi, Emily Forrest; Wilson, David; Hill, Jason

    2016-01-01

    This report provides a "first look" at selected findings from the 2012/14 Beginning Postsecondary Students Longitudinal Study (BPS:12/14). It is based on final data describing a nationally representative sample of undergraduates who entered postsecondary education for the first time during the 2011-12 academic year. BPS:12/14 covers the…

  3. Voice Onset Time of Voiceless Bilabial and Velar Stops in 3-Year-Old Bilingual Children and Their Age-Matched Monolingual Peers

    ERIC Educational Resources Information Center

    Fabiano-Smith, Leah; Bunta, Ferenc

    2012-01-01

    This study investigates aspects of voice onset time (VOT) of voiceless bilabial and velar stops in monolingual and bilingual children. VOT poses a special challenge for bilingual Spanish- and English-speaking children because although this VOT distinction exists in both languages, the values differ for the same contrast across Spanish and English.…

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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...

  10. 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...

  11. 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…

  12. 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...

  13. 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...

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. Leadership Coaching in an Induction Program for Novice Principals: A 3-Year Study

    ERIC Educational Resources Information Center

    Lochmiller, Chad R.

    2014-01-01

    This article presents results from a study of leadership coaches who worked with novice principals in a university-based induction program for a 3-year period. The qualitative case study describes how the support the coaches provided to the novice principals changed over time. The study reveals that coaches adapted their leadership coaching…

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Epidemiology and clinical presentations of the four human coronaviruses 229E, HKU1, NL63, and OC43 detected over 3 years using a novel multiplex real-time PCR method.

    PubMed

    Gaunt, E R; Hardie, A; Claas, E C J; Simmonds, P; Templeton, K E

    2010-08-01

    Four human coronaviruses (HCoV-229E, HCoV-HKU1, HCoV-NL63, and HCoV-OC43) are associated with a range of respiratory outcomes, including bronchiolitis and pneumonia. Their epidemiologies and clinical characteristics are poorly described and are often reliant on case reports. To address these problems, we conducted a large-scale comprehensive screening for all four coronaviruses by analysis of 11,661 diagnostic respiratory samples collected in Edinburgh, United Kingdom, over 3 years between July 2006 and June 2009 using a novel four-way multiplex real-time reverse transcription-PCR (RT-PCR) assay. Coronaviruses were detected in 0.3 to 0.85% of samples in all age groups. Generally, coronaviruses displayed marked winter seasonality between the months of December and April and were not detected in summer months, which is comparable to the pattern seen with influenza viruses. HCoV-229E was the exception; detection was confined to the winter of 2008 and was sporadic in the following year. There were additional longer-term differences in detection frequencies between seasons, with HCoV-OC43 predominant in the first and third seasons and HCoV-HKU1 dominating in the second (see Results for definitions of seasons). A total of 11 to 41% of coronaviruses detected were in samples testing positive for other respiratory viruses, although clinical presentations of coronavirus monoinfections were comparable to those of viruses which have an established role in respiratory disease, such as respiratory syncytial virus, influenza virus, and parainfluenza viruses. The novel multiplex assay for real-time pan-coronavirus detection enhances respiratory virus diagnosis, overcomes potential diagnostic problems arising through seasonal variation in coronavirus frequency, and provides novel insights into the epidemiology and clinical implications of coronaviruses.

  20. 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...

  1. 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.

  2. 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

  3. 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...

  4. 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

  5. Algerian Eddies lifetime can near 3 years

    NASA Astrophysics Data System (ADS)

    Puillat, I.; Taupier-Letage, I.; Millot, C.

    2002-01-01

    The Algerian Current (AC) is unstable and generates mesoscale meanders and eddies. Only anticyclonic eddies can develop and reach diameters over 200 km with vertical extents down to the bottom (˜3000 m). Algerian Eddies (AEs) first propagate eastward along the Algerian slope at few kilometers per day. In the vicinity of the Channel of Sardinia, a few AEs detach from the Algerian slope and propagate along the Sardinian one. It was hypothesized that AEs then followed a counter-clockwise circuit in the eastern part of the basin. Maximum recorded lifetimes were known to exceed 9 months. Within the framework of the 1-year Eddies and Leddies Interdisciplinary Study off Algeria (ELISA) experiment (1997-1998), we exhaustively tracked two AEs, using mainly an ˜3-year time series of NOAA/AVHRR satellite images. We show that AEs lifetimes can near 3 years, exceeding 33 months at least. We also confirm the long-lived AEs preferential circuit in the eastern part of the Algerian Basin, and specify that it may include several loops (at least three).

  6. 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(*).

  7. 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

  8. 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.

  9. 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.

  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. 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.

  12. How Grammatical Are 3-Year-Olds?

    ERIC Educational Resources Information Center

    Eisenberg, Sarita L.; Guo, Ling-Yu; Germezia, Mor

    2012-01-01

    Purpose: This study investigated the level of grammatical accuracy in typically developing 3-year-olds and the types of errors they produce. Method: Twenty-two 3-year-olds participated in a picture description task. The percentage of grammatical utterances was computed and error types were analyzed. Results: The mean level of grammatical accuracy…

  13. 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.

  14. 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.

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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.

  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. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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.

  20. 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.

  1. AID awards 3-year Guatemala contract.

    PubMed

    1984-01-01

    The US Agency for International Development (USAID) has awarded a 3-year US$593,036 grant to the Los Angeles firm of Juarez and Associates, Inc. to help implement a contraceptive social marketing project in Guatemala. The firm will provide marketing assistance to the for-profit organization. Importadora de Productos Farmaceuticos (PROFA), an offshoot of the nonprofit International Planned Parenthood Federation affiliate, Asociacion Pro-Bienestar de la Familia de Guatemala (APROFAM), created specifically to conduct the social marketing project. Juarez and Associates has previous market research experience in family planning in Guatemala. Contraceptive social marketing sales are projected to begin in early 1985.

  2. Health Blogging and Social Support: A 3-Year Panel Study.

    PubMed

    Keating, David M; Rains, Stephen A

    2015-01-01

    The reported study explored the implications of informal computer-mediated social support for the well-being of individuals coping with illness over the course of 3 years. A panel study was conducted in which respondents--bloggers writing about their experiences living with a health condition--reported on their perceptions of social support and well-being during 2010 and again during 2013. Among respondents who completed both questionnaires (n = 49), increases in support availability from family and friends were related to improvements in bloggers' health self-efficacy as well as improvements in bloggers' loneliness, particularly among those who also experienced increased support availability from blog readers. Increased blog reader support availability was associated with improvements in bloggers' health-related uncertainty. Among respondents who completed the initial questionnaire (N = 121), a survival analysis showed that neither support available from family and friends nor support from blog readers predicted continued health blogging over the 3-year period.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  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. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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 §...

  8. 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...

  9. 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...

  10. 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…

  11. 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...

  12. 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…

  13. 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

  14. Vascular Calcification in Patients with Nondialysis CKD over 3 Years

    PubMed Central

    Molina, Pablo; Cerverón, M. Jesús; Vila, Rocío; Bover, Jordi; Nieto, Javier; Barril, Guillermina; Martínez-Castelao, Alberto; Fernández, Elvira; Escudero, Verónica; Piñera, Celestino; Adragao, Teresa; Navarro-Gonzalez, Juan F.; Molinero, Luis M.; Castro-Alonso, Cristina; Pallardó, Luis M.; Jamal, Sophie A.

    2015-01-01

    Background and objectives Vascular calcification (VC) is common in CKD, but little is known about its prognostic effect on patients with nondialysis CKD. The prevalence of VC and its ability to predict death, time to hospitalization, and renal progression were assessed. Design, setting, participants, & measurements The Study of Mineral and Bone Disorders in CKD in Spain is a prospective, observational, 3-year follow-up study of 742 patients with nondialysis CKD stages 3–5 from 39 centers in Spain from April to May 2009. VC was assessed using Adragao (AS; x-ray pelvis and hands) and Kauppila (KS; x-ray lateral lumbar spine) scores from 572 and 568 patients, respectively. The primary end point was death. Secondary outcomes were hospital admissions and appearance of a combined renal end point (beginning of dialysis or drop >30% in eGFR). Factors related to VC were assessed by logistic regression analysis. Survival analysis was assessed by Cox proportional models. Results VC was present in 79% of patients and prominent in 47% (AS≥3 or KS>6). Age (odds ratio [OR], 1.05; 95% confidence interval [95% CI], 1.02 to 1.07; P<0.001), phosphorous (OR, 1.68; 95% CI, 1.28 to 2.20; P<0.001), and diabetes (OR, 2.11; 95% CI, 1.32 to 3.35; P=0.002) were independently related to AS≥3. After a median follow-up of 35 months (interquartile range=17–36), there were 70 deaths (10%). After multivariate adjustment for age, smoking, diabetes, comorbidity, renal function, and level of phosphorous, AS≥3 but not KS>6 was independently associated with all-cause (hazard ratio [HR], 2.07; 95% CI, 1.07 to 4.01; P=0.03) and cardiovascular (HR, 3.46; 95% CI, 1.27 to 9.45; P=0.02) mortality as well as a shorter hospitalization event–free period (HR, 1.14; 95% CI, 1.06 to 1.22; P<0.001). VC did not predict renal progression. Conclusions VC is highly prevalent in patients with CKD. VC assessment using AS independently predicts death and time to hospitalization. Therefore, it could be a useful

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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...

  10. 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...

  11. 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...

  12. 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

  13. 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.

  14. 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

  15. 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.

  16. 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

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. A bioactive dental luting cement--its retentive properties and 3-year clinical findings.

    PubMed

    Jefferies, Steven R; Pameijer, Cornelis H; Appleby, David C; Boston, Daniel; Lööf, Jesper

    2013-02-01

    A clinical validation study was conducted to determine the performance of a new bioactive dental cement (Ceramir C&B, Doxa Dental AB) for permanent cementation. The cement is a new formulation class, which is a hybrid material comprised of calcium aluminate and glass-ionomer components. A total of 38 crowns and bridges were cemented in 17 patients; 31 of the abutment teeth were vital and seven were non-vital. Six restorations were bridges with a total of 14 abutment teeth (12 vital/ two non-vital). One fixed splint comprising two abutment teeth was also included. Preparation parameters were recorded, as well as cement characteristics such as working time, setting time, seating characteristics, and ease of cement removal. Baseline data were recorded for the handling of the cement, gingival inflammation, and pre-cementation sensitivity. Post-cementation parameters included post-cementation sensitivity, gingival tissue reaction, marginal integrity, and discoloration. All patients were seen for recall examinations at 30 days and 6 months. Fifteen of 17 subjects and 13 of 17 patients were also available for subsequent comprehensive 1- and 2-year recall examination, and 13 patients were available for a 3-year recall examination. Restorations available for the 3-year recall examination included 14 single-unit full-coverage crown restorations, four three-unit bridges comprising eight abutments, and one two-unit splint. Three-year recall data yielded no loss of retention, no secondary caries, no marginal discolorations, and no subjective sensitivity. All restorations rated excellent for marginal integrity. Average visual analogue scale (VAS) score for tooth sensitivity decreased from 7.63 mm at baseline to 0.44 mm at 6-month recall, 0.20 mm at 1-year recall, and 0.00 mm at 2- and 3-year recall. Average gingival index (GI) score for gingival inflammation decreased from 0.56 at baseline to 0.11 at 6-month recall, 0.16 at 1-year recall, 0.21 at 2-year recall, and 0.07 at 3

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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)].

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. 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.

  17. GRB 030329: 3 years of radio afterglow monitoring.

    PubMed

    van der Horst, A J; Kamble, A; Wijers, R A M J; Resmi, L; Bhattacharya, D; Rol, E; Strom, R; Kouveliotou, C; Oosterloo, T; Ishwara-Chandra, C H

    2007-05-15

    Radio observations of gamma-ray burst (GRB) afterglows are essential for our understanding of the physics of relativistic blast waves, as they enable us to follow the evolution of GRB explosions much longer than the afterglows in any other wave band. We have performed a 3-year monitoring campaign of GRB 030329 with the Westerbork Synthesis Radio Telescopes and the Giant Metrewave Radio Telescope. Our observations, combined with observations at other wavelengths, have allowed us to determine the GRB blast wave physical parameters, such as the total burst energy and the ambient medium density, as well as to investigate the jet nature of the relativistic outflow. Further, by modelling the late-time radio light curve of GRB 030329, we predict that the Low-Frequency Array (30-240 MHz) will be able to observe afterglows of similar GRBs, and constrain the physics of the blast wave during its non-relativistic phase.

  18. 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

  19. 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)].

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. Parental Styles and Religious Values among Teenagers: A 3-Year Prospective Analysis

    ERIC Educational Resources Information Center

    Heaven, Patrick C. L.; Ciarrochi, Joseph; Leeson, Peter

    2010-01-01

    The authors examined the effect of Grade 7 parental styles on Grade 10 religious values. The authors surveyed 784 participants (382 boys, 394 girls; 8 unreported) in Grade 7. The mean age of the group at Time 1 was 12.3 years (SD = 0.5 years). Time 2 occurred 3 years later when students were in Grade 10 (372 boys, 375 girls). In addition to…

  4. Acute epididymitis in Greek children: a 3-year retrospective study.

    PubMed

    Sakellaris, George S; Charissis, Giorgos C

    2008-07-01

    The aim of the study was to compare historical features, physical examination findings, and testicular color Doppler ultrasound in pediatric patients with epididymitis compared to testicular torsion and torsion of the appendix testes. A retrospective review of the medical records of 66 boys presenting with clinical aspects of acute scrotum over a 3-year period was performed. Sixty-six patients were included in the study (29 with epididymitis, 8 with testicular torsion and 12 with torsion of the appendix testis, 4 with scrotal abscesses, 5 with scrotal swelling, and 1 with inflamed epididymal cyst). The duration of symptoms ranged from 6 h to 4 days with a peak on the second day. Urine cultures and viral testes were negative in all patients. Color Doppler ultrasound was diagnostic for epididymitis in 28 patients (96.6%). Systemic intravenous antibiotics were given in all 29 patients with epididymitis. No patient showed signs of testicular atrophy in the follow-up. The increasing incidence of epididymitis should question the policy of routine exploration of the acute scrotum in children. The history and physical examination cannot reliably identify those boys who can be managed conservatively. Color Doppler ultrasound is a useful adjunct in the evaluation of the acute scrotum when physical findings are equivocal but it can also be misleading.

  5. 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.

  6. 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.

  7. 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

  8. 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).

  9. Growth and Your 2- to 3-Year-Old

    MedlinePlus

    ... 1- to 2-Year-Old Growth and Your 2- to 3-Year-Old KidsHealth > For Parents > Growth and Your 2- to 3-Year-Old Print A A A ... 4 pounds (1.8 kilograms) and grow about 2 to 3 inches (5 to 8 centimeters). They' ...

  10. Fitness and Your 2- to 3-Year-Old

    MedlinePlus

    ... 1- to 2-Year-Old Fitness and Your 2- to 3-Year-Old KidsHealth > For Parents > Fitness and Your 2- to 3-Year-Old A A A Kids ... skills are appropriate for this age. By age 2, toddlers should be able to walk and run ...

  11. 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

  12. 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

  13. 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

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. Precise timing of the last interglacial period from mass spectrometric determination of thorium-230 in corals

    NASA Technical Reports Server (NTRS)

    Chen, J. H.; Wasserburg, G. J.; Ku, T.-L.; Edwards, R. Lawrence

    1987-01-01

    The development of mass spectrometric techniques for determination of Th-230 abundance has made it possible to reduce analytical errors in (U-238)-(U-234)-(Th-230) dating of corals even with very small samples. Samples of 6 x 10 to the 8th atoms of Th-230 can be measured to an accuracy of + or - 3 percent (2sigma), and 3 x 10 to the 10th atoms of Th-230 can be measured to an accuracy of + or - 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 C-14 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 post-date, the summer solar insolation high at 65 deg 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.

  9. It's T time: A study on the return period of multivariate problems

    NASA Astrophysics Data System (ADS)

    Michailidi, Eleni Maria; Balistrocchi, Matteo; Bacchi, Baldassare

    2016-04-01

    One of the most important tasks a hydrologist must face is the proper estimation of the 'design values' of a natural variable corresponding to a given Return Period, T, of failures of the hydraulic 'structure' to be designed or verified. Sometimes the 'structure' is simply the embankments, the failure of which corresponds to the outflows of flood runoff on the surrounding land. The widely adopted definition of T, in a problem regarding the maxima of hydrological variables, is "the average time elapsing between two successive occurrences of an event exceeding a certain magnitude of the natural variables". If T is referred to the minima, the symmetric definition pertains to the "average time between two periods during which the variable ranges below a given magnitude". Conventional (and the only accepted) approaches for estimation of T involve a single natural variable (i.e. flood-peak of a river at a given cross section, the daily maximum discharge, the maximum daily rainfall depth observed at a given rain-gauge). The method of estimation of T entails a frequency analysis of the variable of interest, where the design value of a given T is needed to design the structure of interest (e.g. dams, sewers). In other words, T is used as the index value to set the assigned risk level for the hydraulic works. However, a univariate approach in complex problems ignores the effect of significant variables interrelation leading to different risk levels for each quantity of interest and resulting in a completely wrong estimate of the risk. For example, if one considers the flood inflow in a lake around which cities and villages are positioned, the variable to be investigated in relation to the risk assessment is the lake water level. It is obvious that the same water level may occur from very different flood hydrographs, even when the same initial water level and the same rate curve of outflows are considered. This is a consequence of the interaction of at least three joint

  10. Predictors of Reading Development in Deaf Children: A 3-Year Longitudinal Study

    ERIC Educational Resources Information Center

    Kyle, Fiona E.; Harris, Margaret

    2010-01-01

    The development of reading ability in a group of deaf children was followed over a 3-year period. A total of 29 deaf children (7-8 years of age at the first assessment) participated in the study, and every 12 months they were given a battery of literacy, cognitive, and language tasks. Earlier vocabulary and speechreading skills predicted…

  11. Analysis of Satellite sea surface temperature time series in the Brazil-Malvinas Current confluence region: Dominance of the annual and semiannual periods

    NASA Astrophysics Data System (ADS)

    Provost, Christine; Garcia, Omar; GarçOn, VéRonique

    1992-11-01

    We study the dominant periodic variations of sea surface temperature (SST) in the Brazil-Malvinas Confluence region from a satellite-derived data set compiled by Olson et al. (1988). This data set is composed of 202 sea surface temperature images with a 4 × 4 km resolution and extends over 3 years (from July 1984 to July 1987). Each image is a 5-day composite. The dominant signal, as already observed by Podesta et al. (1991), has a 1-year period. We first fit a single-frequency sinusoidal model of the annual cycle in order to estimate mean temperature, amplitude, and phase at 159 points uniformly distributed over the region. The residuals are generally small (less than 2°C). The largest departures from this cycle are located either in the Brazil-Malvinas frontal region or in the southeastern part of the region. Other periods in SST variations are identified by means of periodograms of the 159 residual time series in which the annual cycle has been substracted. The periodograms show that a semiannual frequency signal is present at almost every location. The ratio of the semiannual amplitude to the annual amplitude increases southward from 0% at 30°S to reach up to 45% at 50°S. In the south the semiannual signal creates an asymmetry, and the resulting (total) annual cycle has a cold period (winter) longer than the warm one (summer). In the frontal region the annual and semiannual signals have an important interannual variation. This semiannual frequency is associated with the semiannual wave present in the atmospheric forcing of the southern hemisphere. Differential heating over the mid-latitude oceans and the high-latitude ice-covered Antarctic Continent has been suggested as the cause of this semiannual wave (Van Loon, 1967).

  12. Survival of Bacillus pumilus spores for a prolonged period of time in real space conditions.

    PubMed

    Vaishampayan, Parag A; Rabbow, Elke; Horneck, Gerda; Venkateswaran, Kasthuri J

    2012-05-01

    To prevent forward contamination and maintain the scientific integrity of future life-detection missions, it is important to characterize and attempt to eliminate terrestrial microorganisms associated with exploratory spacecraft and landing vehicles. Among the organisms isolated from spacecraft-associated surfaces, spores of Bacillus pumilus SAFR-032 exhibited unusually high resistance to decontamination techniques such as UV radiation and peroxide treatment. Subsequently, B. pumilus SAFR-032 was flown to the International Space Station (ISS) and exposed to a variety of space conditions via the European Technology Exposure Facility (EuTEF). After 18 months of exposure in the EXPOSE facility of the European Space Agency (ESA) on EuTEF under dark space conditions, SAFR-032 spores showed 10-40% survivability, whereas a survival rate of 85-100% was observed when these spores were kept aboard the ISS under dark simulated martian atmospheric conditions. In contrast, when UV (>110 nm) was applied on SAFR-032 spores for the same time period and under the same conditions used in EXPOSE, a ∼7-log reduction in viability was observed. A parallel experiment was conducted on Earth with identical samples under simulated space conditions. Spores exposed to ground simulations showed less of a reduction in viability when compared with the "real space" exposed spores (∼3-log reduction in viability for "UV-Mars," and ∼4-log reduction in viability for "UV-Space"). A comparative proteomics analysis indicated that proteins conferring resistant traits (superoxide dismutase) were present in higher concentration in space-exposed spores when compared to controls. Also, the first-generation cells and spores derived from space-exposed samples exhibited elevated UVC resistance when compared with their ground control counterparts. The data generated are important for calculating the probability and mechanisms of microbial survival in space conditions and assessing microbial contaminants

  13. 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.

  14. Growth and Your 2- to 3-Year-Old

    MedlinePlus

    ... effective in significantly increasing their final adult height. Constitutional growth delay (delayed puberty). Although they are usually ... about age 2 or 3 years, kids with constitutional growth delay will grow at a normal childhood ...

  15. A 3-year follow-up study of various types of orthodontic canine-to-canine retainers.

    PubMed

    Artun, J; Spadafora, A T; Shapiro, P A

    1997-10-01

    The present study was performed to test the tendency for plaque and calculus build-up along the wire of different types of bonded orthodontic canine-to-canine retainers, whether the presence of such retainers causes any damage to the teeth involved, the failure rate of the retainers, and any changes in incisor alignment during a 3-year period of retention. The four test groups received either retainers made of thick plain wire bonded only to the canines (n = 11); thick spiral wire bonded only to the canines (n = 13); thin, flexible spiral wire bonded to each tooth (n = 11); or removable retainers (n = 14). Accumulation of plaque and calculus along the gingival margin, gingival inflammation and probing attachment level were scored in lingual areas from canine to canine at the time of fixed appliance removal and again 3 years after retainer insertion. Incisor irregularity was measured on plaster models made at the same time periods. Accumulation of plaque and calculus and development of caries along the wire were scored at follow-up. Retainer failures were recorded whenever they occurred. The results revealed no intergroup differences in changes between baseline and follow-up examinations or status along the retainer wire for any of the variables. Gingival inflammation and plaque accumulation were scored less frequently after 3 years in retention than at the time of debonding. No signs of caries were seen adjacent to the wire. Failures were observed of one, four and three of the fixed retainer types, respectively. These patients showed a greater increase in incisor irregularity than the other patients.

  16. SMOS Instrument Performance and Calibration after 3 Years in Orbit

    NASA Astrophysics Data System (ADS)

    Martin-Neira, Manuel; Corbella, Ignasi; Torres, Francesc; Kainulainen, Juha; Oliva, Roger; Closa, Josep; Cabot, François; Castro, Rita; Barbosa, Jose; Gutierrez, Antonio; Anterrieu, Eric; Tenerelli, Joe; Martin-Porqueras, Fernando; Buenadicha, Guillermo; Delwart, Steven; Crapolicchio, Raffaele; Suess, Martin

    2013-04-01

    ESA's Soil Moisture and Ocean Salinity (SMOS) mission has been in orbit for already over 3 years which has allowed the calibration and data processing team consolidating both the calibration strategy and the Level-1 processor which transforms the raw visibility samples into polarimetric brightness temperature images. The payload on board SMOS, MIRAS, is quite unique in that it is the first microwave radiometer in space ever capable to generate wide field of view images at every snapshot measurement. This means that most of the calibration as well as image processing techniques are being developed for the first time with little heritage from any previous space mission. Issues intrinsically attached to its wide field of view such as spatial ripples across the snapshot images are particular to MIRAS and to no other earlier radiometer. Even the fundamental theory behind the instrument was put at test, first on ground inside an electromagnetic compatibility chamber, and now in orbit when imaging the Cosmic Microwave Background Radiation of the cold sky. A groundbreaking effort is being carried out by the SMOS project team to understand and master all calibration and image reconstruction issues of this novel microwave interferometer payload. MIRAS in-orbit performance is driven by the amplitude of spatial ripples across the image and orbital and seasonal radiometer stability. Spatial ripples are unique to interferometric radiometers and are produced by (a) a limited knowledge of the antenna patterns and, in general, of the model of the instrument, (b) some fundamental limitations related to the inverse problem of image reconstruction in undetermined conditions and (c) subtle data processing inconsistencies which are discovered and corrected. To reduce the spatial ripples sea surface salinity retrievals are performed by first removing the brightness temperature spatial errors using a uniform region of the Pacific Ocean. However soil moisture retrievals cannot benefit of

  17. Timing analysis of the periodic radio and optical brightness variations of the ultracool dwarf, TVLM 513-46546

    SciTech Connect

    Wolszczan, A.; Route, M. E-mail: matthew.route@ngc.com

    2014-06-10

    We describe the arrival time measurements and timing modeling of the periodic radio flares and optical brightness variations of the M9 ultracool dwarf, TVLM 513-46546. We confirm the stability of the observed period and determine its best-fit value to be 7054.468 ± 0.007 s over the last 7 yr, based on both the new and archival radio observations and the archival optical data. The period, when measured separately for the radio flare and the optical periodicities, is the same to within ±0.02 s. We show that the radio flares are out of phase with respect to the optical brightness maxima by 0.41 ± 0.02 of the period. Our analysis also reveals that, on shorter timescales, the period varies with the amplitude of ±1-2 s about its long-term average and that these variations are correlated between the radio and the optical wavelengths. These results provide further evidence that TVLM 513-46546 is equipped with a stable, approximately dipolar magnetic field that powers the activity of the star observed over a wide wavelength range, and that the active area has been maintaining its identity and positional stability over no less than 7 yr. A stepwise decline of the apparent radio flaring period of TVLM 513-46546, deduced from timing observations with the Arecibo radio telescope in late 2012 and early 2013, suggests that this effect may be the manifestation of differential rotation of the star.

  18. Assessment of High-rate GPS time series at long periods

    NASA Astrophysics Data System (ADS)

    Kelevitz, K.; Houlie, N.; Giardini, D.; Rothacher, M.

    2015-12-01

    We present the comparison of 1 Hz GPS waveforms and very broadband seismic waveforms recorded during and after three mega-thrust earthquakes (2003 Hokkaido, 2004 Sumatra and 2011 Tohoku-Oki) for various period bands (T > 30 s) and distances from the epicenter. With this study we aim at providing valuable data between periods of 300s and 1200s, corresponding to long-period surface waves and the first normal mode of the free oscillation of the Earth, respectively. We assess the performance of each dataset at the light of comparisons with synthetic seismic displacement waveforms. We find that GPS is well capable of recovering millimetre ground motion oscillations in a wide range of periods (30 - 1300 s), potentially providing valuable information on the lithosphere and upper-mantle heterogeneities on a scale of 300 - 3000 km. With the aim of building a database of GPS waveforms we have conducted a study of different processing techniques with the GAMIT and Bernese GPS data processing packages. We show the outline of the planned GPS waveform database, which consists of long period surface wave records of large earthquakes (Mw > 7) of the last decades, and could be used for various seismological applications.

  19. 45 CFR 287.55 - What time frames and guidelines apply regarding the obligation and liquidation periods for NEW...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 2 2011-10-01 2011-10-01 false What time frames and guidelines apply regarding the obligation and liquidation periods for NEW Program funds? 287.55 Section 287.55 Public Welfare... NEW Program Funding § 287.55 What time frames and guidelines apply regarding the obligation...

  20. 41 CFR 302-11.23 - When must I request to have my initial time period extended?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... have my initial time period extended? 302-11.23 Section 302-11.23 Public Contracts and Property Management Federal Travel Regulation System RELOCATION ALLOWANCES RESIDENCE TRANSACTION ALLOWANCES 11-ALLOWANCES FOR EXPENSES INCURRED IN CONNECTION WITH RESIDENCE TRANSACTIONS General Rules Time...

  1. 41 CFR 302-11.23 - When must I request to have my initial time period extended?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... have my initial time period extended? 302-11.23 Section 302-11.23 Public Contracts and Property Management Federal Travel Regulation System RELOCATION ALLOWANCES RESIDENCE TRANSACTION ALLOWANCES 11-ALLOWANCES FOR EXPENSES INCURRED IN CONNECTION WITH RESIDENCE TRANSACTIONS General Rules Time...

  2. 41 CFR 302-11.23 - When must I request to have my initial time period extended?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... have my initial time period extended? 302-11.23 Section 302-11.23 Public Contracts and Property Management Federal Travel Regulation System RELOCATION ALLOWANCES RESIDENCE TRANSACTION ALLOWANCES 11-ALLOWANCES FOR EXPENSES INCURRED IN CONNECTION WITH RESIDENCE TRANSACTIONS General Rules Time...

  3. 41 CFR 302-11.23 - When must I request to have my initial time period extended?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... have my initial time period extended? 302-11.23 Section 302-11.23 Public Contracts and Property Management Federal Travel Regulation System RELOCATION ALLOWANCES RESIDENCE TRANSACTION ALLOWANCES 11-ALLOWANCES FOR EXPENSES INCURRED IN CONNECTION WITH RESIDENCE TRANSACTIONS General Rules Time...

  4. 41 CFR 302-11.23 - When must I request to have my initial time period extended?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... have my initial time period extended? 302-11.23 Section 302-11.23 Public Contracts and Property Management Federal Travel Regulation System RELOCATION ALLOWANCES RESIDENCE TRANSACTION ALLOWANCES 11-ALLOWANCES FOR EXPENSES INCURRED IN CONNECTION WITH RESIDENCE TRANSACTIONS General Rules Time...

  5. [Local fractal analysis of noise-like time series by all permutations method for 1-115 min periods].

    PubMed

    Panchelyuga, V A; Panchelyuga, M S

    2015-01-01

    Results of local fractal analysis of 329-per-day time series of 239Pu alpha-decay rate fluctuations by means of all permutations method (APM) are presented. The APM-analysis reveals in the time series some steady frequency set. The coincidence of the frequency set with the Earth natural oscillations was demonstrated. A short review of works by different authors who analyzed the time series of fluctuations in processes of different nature is given. We have shown that the periods observed in those works correspond to the periods revealed in our study. It points to a common mechanism of the phenomenon observed.

  6. Deformation Time Series Monitoring Of Nisyros Volcano (Greece) During Unrest And Rest Period

    NASA Astrophysics Data System (ADS)

    Derdelakos, K.; Parcharidis, I.; Benekos, G.; Papageorgiou, E.

    2013-12-01

    Nisyros Volcano (SW Greece) shows an unrest phase during 1996-97 accompanied by intensive seismic activity in the broader area at the beginning of 1996 and lasted through the end of 1997 and returned to the background level at the beginning of 1998. SAR interferometry has already shown its ability in mapping ground deformation, like co-seismic deformation, as well as long-term movements as is the ground deformation in volcanoes, landslides and subsidence. Ground deformation monitoring is one of the main parameters that should be considered to assess volcanic hazard. In the current study the multi-reference synthetic aperture radar (SAR) interferometric technique was applied in order to study the evolution of ground deformation during the unrest period 1996-1997 and the post period of 2003-2010. Two different data sets of common acquisition geometry of radar scenes covering the mention periods were used.

  7. Periodic optical rogue waves (PORWs) in parity-time (PT) symmetric Bragg-grating structure

    NASA Astrophysics Data System (ADS)

    Gupta, Samit Kumar; Sarma, Amarendra K.

    2014-10-01

    In this work, we present an analytical investigation of traveling wave solution in a nonlinear Bragg grating structure with the core of the optical fiber having PT-symmetric refractive index distribution. Under the approximation of weak-nonlinearity and above the PT-threshold region, the existence of highly intense, well-localized periodic train of pulses has been explored for the backward-propagating wave for some suitable choice of the parameter values of the system. The result of the present study might be useful in practical purpose in generating high-power, periodic optical pulses.

  8. Comment on "Time-averaged properties of unstable periodic orbits and chaotic orbits in ordinary differential equation systems".

    PubMed

    Zaks, Michael A; Goldobin, Denis S

    2010-01-01

    A recent paper claims that mean characteristics of chaotic orbits differ from the corresponding values averaged over the set of unstable periodic orbits, embedded in the chaotic attractor. We demonstrate that the alleged discrepancy is an artifact of the improper averaging. Since the natural measure is nonuniformly distributed over the attractor, different periodic orbits make different contributions into the time averages. As soon as the corresponding weights are accounted for, the discrepancy disappears.

  9. 45 CFR 402.26 - Time period for obligation and expenditure of grant funds.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... REFUGEE RESETTLEMENT, ADMINISTRATION FOR CHILDREN AND FAMILIES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... State of funds awarded under § 402.31 and § 402.33 must be liquidated within the time limit set by 45 CFR 92.23(b). This time limit will not be extended. The time limit established by 45 CFR 92.23(b)...

  10. A new method for determining the long-period component of the source time function of large earthquakes

    SciTech Connect

    Zhang, Jiajun; Lay, T. )

    1989-04-01

    Inversions of seismic body waves indicate that most large earthquakes involve spatial and temporal heterogeneity of the moment release, but seismic body waves usually lack sufficient bandwidth to constrain the long-period component of the radiation. Analysis of long-period surface waves and free oscillations can constrain the overall source duration and moment; however, most procedures assume simple trapezoidal or boxcar source-time histories, inconsistent with the body wave complexity. The authors find that source-time function complexity can affect long-period surface waves sufficiently to impact estimates of the source moment tensor, rupture duration and centroid depth. They present a procedure to objectively determine the long-period component of complex source-time functions in which they directly utilize results from body wave analysis. The method is applied to two great normal fault events of June 22, 1977 (Tonga, M{sub w} = 8.2) and August 19, 1977 (Indonesia, M{sub w} = 8.5). Standard long period analysis procedures underestimate the total slip duration in both cases. The overall source process times of both earthquakes are longer than 120 s.

  11. Existence and global exponential stability of periodic solutions for n-dimensional neutral dynamic equations on time scales.

    PubMed

    Li, Bing; Li, Yongkun; Zhang, Xuemei

    2016-01-01

    In this paper, by using the existence of the exponential dichotomy of linear dynamic equations on time scales and the theory of calculus on time scales, we study the existence and global exponential stability of periodic solutions for a class of n-dimensional neutral dynamic equations on time scales. We also present an example to illustrate the feasibility of our results. The results of this paper are completely new and complementary to the previously known results even in both the case of differential equations (time scale [Formula: see text]) and the case of difference equations (time scale [Formula: see text]).

  12. A charged particle in a homogeneous magnetic field accelerated by a time-periodic Aharonov-Bohm flux

    SciTech Connect

    Kalvoda, T.; Stovicek, P.

    2011-10-15

    We consider a nonrelativistic quantum charged particle moving on a plane under the influence of a uniform magnetic field and driven by a periodically time-dependent Aharonov-Bohm flux. We observe an acceleration effect in the case when the Aharonov-Bohm flux depends on time as a sinusoidal function whose frequency is in resonance with the cyclotron frequency. In particular, the energy of the particle increases linearly for large times. An explicit formula for the acceleration rate is derived with the aid of the quantum averaging method, and then it is checked against a numerical solution and a very good agreement is found. - Highlights: > A nonrelativistic quantum charged particle on a plane. > A homogeneous magnetic field and a periodically time-dependent Aharonov-Bohm flux. > The quantum averaging method applied to a time-dependent system. > A resonance of the AB flux with the cyclotron frequency. > An acceleration with linearly increasing energy; a formula for the acceleration rate.

  13. The time-periodic diffusive competition models with a free boundary and sign-changing growth rates

    NASA Astrophysics Data System (ADS)

    Wang, Mingxin; Zhang, Yang

    2016-10-01

    To understand the spreading of invasive and native species, in this paper we consider the diffusive competition models with a free boundary in the heterogeneous time-periodic environments, in which the variable intrinsic growth rates of these two species change signs and may be very negative in some large regions. We study the spreading-vanishing dichotomy, long-time dynamical behavior of solution, sharp criteria for spreading and vanishing, and estimates of the asymptotic spreading speed of the free boundary. Moreover, we establish the existence of positive solutions to a T-periodic boundary value problem of the diffusive competition system with sign-changing growth rates in the half line.

  14. A mapping method for distributive mixing with diffusion: Interplay between chaos and diffusion in time-periodic sine flow

    NASA Astrophysics Data System (ADS)

    Schlick, Conor P.; Christov, Ivan C.; Umbanhowar, Paul B.; Ottino, Julio M.; Lueptow, Richard M.

    2013-05-01

    We present an accurate and efficient computational method for solving the advection-diffusion equation in time-periodic chaotic flows. The method uses operator splitting, which allows the advection and diffusion steps to be treated independently. Taking advantage of flow periodicity, the advection step is solved using a mapping method, and diffusion is "added" discretely after each iteration of the advection map. This approach results in the construction of a composite mapping matrix over an entire period of the chaotic advection-diffusion process and provides a natural framework for the analysis of mixing. To test the approach, we consider two-dimensional time-periodic sine flow. By comparing the numerical solutions obtained by our method to reference solutions, we find qualitative agreement for large time steps (structure of concentration profile) and quantitative agreement for small time steps (low error). Further, we study the interplay between mixing through chaotic advection and mixing through diffusion leading to an analytical model for the evolution of the intensity of segregation with time. Additionally, we demonstrate that our operator splitting mapping approach can be readily extended to three dimensions.

  15. Similarity Predicts Liking in 3-Year-Old Children

    ERIC Educational Resources Information Center

    Fawcett, Christine A.; Markson, Lori

    2010-01-01

    Two studies examined the influence of similarity on 3-year-old children's initial liking of their peers. Children were presented with pairs of childlike puppets who were either similar or dissimilar to them on a specified dimension and then were asked to choose one of the puppets to play with as a measure of liking. Children selected the puppet…

  16. Developing Dialogic Argumentation Skills: A 3-Year Intervention Study

    ERIC Educational Resources Information Center

    Crowell, Amanda; Kuhn, Deanna

    2014-01-01

    Argumentation is increasingly recognized as a fundamental intellectual skill, but evidence suggests that few adolescents or adults are skilled arguers. This article reports on an extended (3-year, twice weekly) intervention designed to afford dense practice in dialogic argumentation to middle-school students from traditionally academically…

  17. Framing Health Messages for Adolescents: Should We Use Objective Time Periods, Temporal Benchmarks, or Both?

    ERIC Educational Resources Information Center

    McKay, Michael T.; Cole, Jon C.; Sumnall, Harry R.; Goudie, Andrew J.

    2012-01-01

    Time perspective is a cognitive-motivational construct, which has been shown to be related to decision-making, motivation and adjustment. The majority of research into time perspective has been conducted in college students and/or general population samples. Focus groups were held as part of a larger investigation into the relationship between…

  18. Time-periodic solutions of massive scalar fields in dynamical AdS background: Perturbative constructions

    NASA Astrophysics Data System (ADS)

    Kim, Nakwoo

    2015-03-01

    We consider scalar fields which are coupled to Einstein gravity with a negative cosmological constant, and construct periodic solutions perturbatively. In particular, we study tachyonic scalar fields whose mass is at or above the Breitenlohner-Freedman bound in four, five, and seven spacetime dimensions. The critical amplitude of the leading order perturbation, for which the perturbative expansion breaks down, increases as we consider less massive fields. We present various examples including a model with a self-interacting scalar field which is derived from a consistent truncation of IIB supergravity.

  19. Space Radiation Cancer Risks and Uncertainities for Different Mission Time Periods

    NASA Technical Reports Server (NTRS)

    Kim,Myung-Hee Y.; Cucinotta, Francis A.

    2012-01-01

    Space radiation consists of solar particle events (SPEs), comprised largely of medium energy protons (less than several hundred MeV); and galactic cosmic ray (GCR), which includes high energy protons and high charge and energy (HZE) nuclei. For long duration missions, space radiation presents significant health risks including cancer mortality. Probabilistic risk assessment (PRA) is essential for radiation protection of crews on long term space missions outside of the protection of the Earth s magnetic field and for optimization of mission planning and costs. For the assessment of organ dosimetric quantities and cancer risks, the particle spectra at each critical body organs must be characterized. In implementing a PRA approach, a statistical model of SPE fluence was developed, because the individual SPE occurrences themselves are random in nature while the frequency distribution of SPEs depends strongly upon the phase within the solar activity cycle. Spectral variability of SPEs was also examined, because the detailed energy spectra of protons are important especially at high energy levels for assessing the cancer risk associated with energetic particles for large events. An overall cumulative probability of a GCR environment for a specified mission period was estimated for the temporal characterization of the GCR environment represented by the deceleration potential (theta). Finally, this probabilistic approach to space radiation cancer risk was coupled with a model of the radiobiological factors and uncertainties in projecting cancer risks. Probabilities of fatal cancer risk and 95% confidence intervals will be reported for various periods of space missions.

  20. Space-time kriging of precipitation variability in Turkey for the period 1976-2010

    NASA Astrophysics Data System (ADS)

    Raja, Nussaïbah B.; Aydin, Olgu; Türkoğlu, Necla; Çiçek, Ihsan

    2016-03-01

    The purpose of this study is to revaluate the changing spatial and temporal trends of precipitation in Turkey. Turkey is located in one of the regions at greatest risk from the potential effects of climate change. Since the 1970s, a decreasing trend in annual precipitation has been observed, in addition to an increasing number of precipitation-related natural hazards such as floods, extreme precipitation, and droughts. An understanding of the temporal and spatial characteristics of precipitation is therefore crucial to hazard management as well as planning and managing water resources, which depend heavily on precipitation. The ordinary kriging method was employed to interpolate precipitation estimates using precipitation records from 228 meteorological stations across the country for the period 1976-2010. A decreasing trend was observed across the Central Anatolian region, except for 1996-2000 which saw an increase in precipitation. However, this same period is identified as the driest year in Eastern and South Eastern Anatolia. The Eastern Black Sea region has the highest precipitation in the country; after 1996, an increase in annual precipitation in this region is observed. An overall reduction is also seen in southwest Turkey, with less variation in precipitation.

  1. Time-resolved measurement of Landau-Zener tunneling in periodic potentials.

    PubMed

    Zenesini, A; Lignier, H; Tayebirad, G; Radogostowicz, J; Ciampini, D; Mannella, R; Wimberger, S; Morsch, O; Arimondo, E

    2009-08-28

    We report time-resolved measurements of Landau-Zener tunneling of Bose-Einstein condensates in accelerated optical lattices, clearly resolving the steplike time dependence of the band populations. Using different experimental protocols we were able to measure the tunneling probability both in the adiabatic and in the diabatic bases of the system. We also experimentally determine the contribution of the momentum width of the Bose condensates to the temporal width of the tunneling steps and discuss the implications for measuring the jump time in the Landau-Zener problem.

  2. Time-Resolved Measurement of Landau-Zener Tunneling in Periodic Potentials

    SciTech Connect

    Zenesini, A.; Radogostowicz, J.; Ciampini, D.; Mannella, R.; Arimondo, E.; Lignier, H.; Morsch, O.; Tayebirad, G.; Wimberger, S.

    2009-08-28

    We report time-resolved measurements of Landau-Zener tunneling of Bose-Einstein condensates in accelerated optical lattices, clearly resolving the steplike time dependence of the band populations. Using different experimental protocols we were able to measure the tunneling probability both in the adiabatic and in the diabatic bases of the system. We also experimentally determine the contribution of the momentum width of the Bose condensates to the temporal width of the tunneling steps and discuss the implications for measuring the jump time in the Landau-Zener problem.

  3. Existence and global exponential stability of periodic solution for high-order discrete-time BAM neural networks.

    PubMed

    Zhang, Ancai; Qiu, Jianlong; She, Jinhua

    2014-02-01

    This paper concerns the existence and exponential stability of periodic solution for the high-order discrete-time bidirectional associative memory (BAM) neural networks with time-varying delays. First, we present the criteria for the existence of periodic solution based on the continuation theorem of coincidence degree theory and the Young's inequality, and then we give the criteria for the global exponential stability of periodic solution by using a non-Lyapunov method. After that, we give a numerical example that demonstrates the effectiveness of the theoretical results. The criteria presented in this paper are easy to verify. In addition, the proposed analysis method is easy to extend to other high-order neural networks.

  4. Errors in visuo-haptic and haptic-haptic location matching are stable over long periods of time.

    PubMed

    Kuling, Irene A; Brenner, Eli; Smeets, Jeroen B J

    2016-05-01

    People make systematic errors when they move their unseen dominant hand to a visual target (visuo-haptic matching) or to their other unseen hand (haptic-haptic matching). Why they make such errors is still unknown. A key question in determining the reason is to what extent individual participants' errors are stable over time. To examine this, we developed a method to quantify the consistency. With this method, we studied the stability of systematic matching errors across time intervals of at least a month. Within this time period, individual subjects' matches were as consistent as one could expect on the basis of the variability in the individual participants' performance within each session. Thus individual participants make quite different systematic errors, but in similar circumstances they make the same errors across long periods of time.

  5. Advantages and drawbacks of applying periodic time-variant modal analysis to spur gear dynamics

    NASA Astrophysics Data System (ADS)

    Pedersen, Rune; Santos, Ilmar F.; Hede, Ivan A.

    2010-07-01

    A simplified torsional model with a reduced number of degrees-of-freedom is used in order to investigate the potential of the technique. A time-dependent gear mesh stiffness function is introduced and expanded in a Fourier series. The necessary number of Fourier terms is determined in order to ensure sufficient accuracy of the results. The method of time-variant modal analysis is applied, and the changes in the fundamental and the parametric resonance frequencies as a function of the rotational speed of the gears, are found. By obtaining the stationary and parametric parts of the time-dependent modes shapes, the importance of the time-varying component relative to the stationary component is investigated and quantified. The method used for calculation and subsequent sorting of the left and right eigenvectors based on a first order Taylor expansion is explained. The advantages and drawbacks of applying the methodology to wind turbine gearboxes are addressed and elucidated.

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

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false When may I flare or vent gas for extended... Production Requirements Flaring, Venting, and Burning Hydrocarbons § 250.1161 When may I flare or vent gas... flare or vent gas for an extended period of time. The Regional Supervisor will specify the...

  7. 20 CFR 663.530 - Is there a time limit on the period of initial eligibility for training providers?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 4 2012-04-01 2012-04-01 false Is there a time limit on the period of initial eligibility for training providers? 663.530 Section 663.530 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) ADULT AND DISLOCATED WORKER ACTIVITIES UNDER...

  8. Time dependent human hip joint lubrication for periodic motion with stochastic asymmetric density function.

    PubMed

    Wierzcholski, Krzysztof

    2014-01-01

    The present paper is concerned with the calculation of the human hip joint parameters for periodic, stochastic unsteady, motion with asymmetric probability density function for gap height. The asymmetric density function indicates that the stochastic probabilities of gap height decreasing are different in comparison with the probabilities of the gap height increasing. The models of asymmetric density functions are considered on the grounds of experimental observations. Some methods are proposed for calculation of pressure distributions and load carrying capacities for unsteady stochastic conditions in a super thin layer of biological synovial fluid inside the slide biobearing gap limited by a spherical bone acetabulum. Numerical calculations are performed in Mathcad 12 Professional Program, by using the method of finite differences. This method assures stability of numerical solutions of partial differential equations and gives proper values of pressure and load carrying capacity forces occurring in human hip joints.

  9. Numerical evaluation of the PERTH (PERiodic Tracer Hierarchy) method for estimating time-variable travel time distribution in variably saturated soils

    NASA Astrophysics Data System (ADS)

    Kim, M.; Harman, C. J.

    2013-12-01

    The distribution of water travel times is one of the crucial hydrologic characteristics of the catchment. Recently, it has been argued that a rigorous treatment of travel time distributions should allow for their variability in time because of the variable fluxes and partitioning of water in the water balance, and the consequent variable storage of a catchment. We would like to be able to observe the structure of the temporal variations in travel time distributions under controlled conditions, such as in a soil column or under irrigation experiments. However, time-variable travel time distributions are difficult to observe using typical active and passive tracer approaches. Time-variability implies that tracers introduced at different times will have different travel time distributions. The distribution may also vary during injection periods. Moreover, repeat application of a single tracer in a system with significant memory leads to overprinting of break-through curves, which makes it difficult to extract the original break-through curves, and the number of ideal tracers that can be applied is usually limited. Recognizing these difficulties, the PERTH (PERiodic Tracer Hierarchy) method has been developed. The method provides a way to estimate time-variable travel time distributions by tracer experiments under controlled conditions by employing a multi-tracer hierarchy under periodical hydrologic forcing inputs. The key assumption of the PERTH method is that as time gets sufficiently large relative to injection time, the average travel time distribution of two distinct ideal tracers injected during overlapping periods become approximately equal. Thus one can be used as a proxy for the other, and the breakthrough curves of tracers applied at different times in a periodic forcing condition can be separated from one another. In this study, we tested the PERTH method numerically for the case of infiltration at the plot scale using HYDRUS-1D and a particle

  10. UTILISATION ANALYSIS OF ANTIHYPERTENSIVE DRUGS IN BOSNIA AND HERZEGOVINA FOR THE TIME-PERIOD 2013–2015

    PubMed Central

    Selmanovic, Kenan; Zec, Svjetlana Loga; Vanis, Nenad; Zecevic, Lamija; Setkic, Manja; Rasic, Azra; Zerem, Enver

    2016-01-01

    Objective: Expenditures for drugs are increasingly burdening already insufficient funds for health protection. This is especially evident in less developed European countries such as Bosnia and Herzegovina. The question is whether such analyses can help save funds for financing treatment for diseases, with an emphasis on a more rational choice of drug for appropriate indication, whereby clinical complications of hypertension would be prevented and patients would have quality of their lives improved. Aim: Focus of research has been set on analysis of use of antihypertensive drugs in Bosnia and Herzegovina in the time-period January 2013–March 2015. Use of all drugs for treatment of hypertension in that time-period in the country has been shown in an unbiased manner. Methods: The study is designed as retrospective-prospective comparative research of use of antihypertensive drugs in BiH in a certain time-period. Data are collected from relevant drug utilisation database which has been established in Bosnia and Herzegovina since 2013. Results: We have calculated financial expenditure for prescribed antihypertensives in the time- period of 2013, 2014 and Q1 2015. Use of antihypertensives at the country level for this time-period is BAM 200,242,218. At the country level, physicians are most often opting for combination therapy: ACE inhibitors + diuretics (20.2%) and ACE inhibitors + Ca channel antagonists (18.0%). Conclusion: In this research, it has been shown that modern drugs are used for treatment of hypertension in Bosnia and Herzegovina. These drugs are used in the same order as they are prescribed in developed countries. PMID:27147917

  11. Lunar periodicity and the timing of river entry in Atlantic salmon Salmo salar.

    PubMed

    Kuparinen, A; O'Hara, R B; Merilä, J

    2009-07-01

    Historical catch records of Atlantic salmon Salmo salar from three rivers discharging to the Baltic Sea in an area free from tides and from strong effects of the moon on illumination were analysed to investigate whether timing of S. salar river entry was associated with lunar cycles directly. Although a significant effect of lunar phase on river entry was detected, with more fish entering rivers around the full moon than other phases, the effect of the lunar cycle was very small compared with other sources of variation. Hence, the biological role of lunar cycle as a determinant of the timing of S. salar runs in the investigated populations was negligible, suggesting that lunar cycle per se does not play a role in the timing of S. salar river entry.

  12. Neuregulin-Dependent Regulation of Fast-Spiking Interneuron Excitability Controls the Timing of the Critical Period.

    PubMed

    Gu, Yu; Tran, Trinh; Murase, Sachiko; Borrell, Andrew; Kirkwood, Alfredo; Quinlan, Elizabeth M

    2016-10-05

    Maturation of excitatory drive onto fast-spiking interneurons (FS INs) in the visual cortex has been implicated in the control of the timing of the critical period for ocular dominance plasticity. However, the mechanisms that regulate the strength of these synapses over cortical development are not understood. Here we use a mouse model to show that neuregulin (NRG) and the receptor tyrosine kinase erbB4 regulate the timing of the critical period. NRG1 enhanced the strength of excitatory synapses onto FS INs, which inhibited ocular dominance plasticity during the critical period but rescued plasticity in transgenics with hypoexcitable FS INs. Blocking the effects of endogenous neuregulin via inhibition of erbBs rescued ocular dominance plasticity in postcritical period adults, allowing recovery from amblyopia induced by chronic monocular deprivation. Thus, the strength of excitation onto FS INs is a key determinant of critical period plasticity and is maintained at high levels by NRG-erbB4 signaling to constrain plasticity in adulthood.

  13. 40 CFR 93.162 - Emissions beyond the time period covered by the SIP.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... including the emissions in the existing SIP or establishing an enforceable commitment to include the.... No such commitment by a State or Tribe shall restrict a State's or Tribe's ability to require RACT, RACM or any other control measures within the State's or Tribe's authority to ensure timely...

  14. The structure of executive function in 3-year-olds.

    PubMed

    Wiebe, Sandra A; Sheffield, Tiffany; Nelson, Jennifer Mize; Clark, Caron A C; Chevalier, Nicolas; Espy, Kimberly Andrews

    2011-03-01

    Although the structure of executive function (EF) during adulthood is characterized by both unity and diversity, recent evidence suggests that preschool EF may be best described by a single factor. The latent structure of EF was examined in 228 3-year-olds using confirmatory factor analysis. Children completed a battery of executive tasks that differed in format and response requirements and in putative working memory and inhibitory control demands. Tasks appeared to be age appropriate, with adequate sensitivity across the range of performance and without floor or ceiling effects. Tests of the relative fit of several alternative models supported a single latent EF construct. Measurement invariance testing revealed less proficient EF in children at higher sociodemographic risk relative to those at lower risk and no differences between boys and girls. At 3years of age, when EF skills are emerging, EF appears to be a unitary, more domain-general process.

  15. A procedure of multiple period searching in unequally spaced time-series with the Lomb-Scargle method

    NASA Technical Reports Server (NTRS)

    Van Dongen, H. P.; Olofsen, E.; VanHartevelt, J. H.; Kruyt, E. W.; Dinges, D. F. (Principal Investigator)

    1999-01-01

    Periodogram analysis of unequally spaced time-series, as part of many biological rhythm investigations, is complicated. The mathematical framework is scattered over the literature, and the interpretation of results is often debatable. In this paper, we show that the Lomb-Scargle method is the appropriate tool for periodogram analysis of unequally spaced data. A unique procedure of multiple period searching is derived, facilitating the assessment of the various rhythms that may be present in a time-series. All relevant mathematical and statistical aspects are considered in detail, and much attention is given to the correct interpretation of results. The use of the procedure is illustrated by examples, and problems that may be encountered are discussed. It is argued that, when following the procedure of multiple period searching, we can even benefit from the unequal spacing of a time-series in biological rhythm research.

  16. Directly Observed Physical Activity among 3-Year-Olds in Finnish Childcare

    ERIC Educational Resources Information Center

    Soini, Anne; Villberg, Jari; Sääkslahti, Arja; Gubbels, Jessica; Mehtälä, Anette; Kettunen, Tarja; Poskiparta, Marita

    2014-01-01

    The main purpose of the study was to determine 3-year-olds' physical activity levels and how these vary across season, gender, time of day, location, and the physical and social environment in childcare settings in Finland. A modified version of the Observational System for Recording Physical Activity in Children-Preschool (OSRAC-P) was used to…

  17. Trajectories of Maternal Harsh Parenting in the First 3 Years of Life

    ERIC Educational Resources Information Center

    Kim, Hyoun K.; Pears, Katherine C.; Fisher, Philip A.; Connelly, Cynthia D.; Landsverk, John A.

    2010-01-01

    Objective: Despite the high prevalence rates of harsh parenting, the nature of developmental change in this domain early in life and the factors that contribute to changes in harsh parenting over time are not well understood. The present study examined developmental patterns in maternal harsh parenting behavior from birth to age 3 years and their…

  18. Predominant periods in the time series of drought area index for the Western High Plains AD 1700 to 1962

    NASA Technical Reports Server (NTRS)

    Bell, P. R.

    1981-01-01

    The detection of the combined presence of the Hale magnetic sunspot cycle (22.28 years) and the lunar nodal tidal cycle (18.61 years) in both the Eastern North American January air temperatures and the Western U.S. High Plains drought series led to an extended analysis of the Drought Area Index time series. This analysis indicated that the mean dominant period of the drought series should be 20.0 to 20.5 years and that the principal period should be resolvable into two components of about 22.28 and 18.61 years. This note details the successful accomplishment of this task.

  19. [Dermatobia hominis infection in a 3-year-old child].

    PubMed

    Meissner, M; Kippenberger, S; Valesky, E M; Kaufmann, R

    2012-04-01

    In the context of increasing travel to the tropics, outpatient services are more frequently confronted with non-domestic diseases in Europe. A 3-year old child presented with a painful tumor of the scalp. After incision of the furuncle-like lesion, we extracted a larva of the botfly Dermatobia hominis. Botflies are mainly encountered in Central and South America; they should be considered if patients demonstrate a furuncle-like lesion and have returned from a holiday in these endemic regions.

  20. Analysis of log-periodic power law singularity patterns in time series related to credit risk

    NASA Astrophysics Data System (ADS)

    Wosnitza, Jan Henrik; Sornette, Didier

    2015-04-01

    The log-periodic (super-exponential) power law singularity (LPPLS) has become a promising tool for predicting extreme behavior of self-organizing systems in natural sciences and finance. Some researchers have recently proposed to employ the LPPLS on credit risk markets. The review article at hand summarizes four papers in this field and shows how they are linked. After structuring the research questions, we collect the corresponding answers from the four articles. This eventually gives us an overall picture of the application of the LPPLS to credit risk data. Our literature review begins with grounding the view that credit default swap (CDS) spreads are hotbeds for LPPLS patterns and it ends up with drawing attention to the recently proposed alarm index for the prediction of institutional bank runs. By presenting a new field of application for the LPPLS, the reviewed strand of literature further substantiates the LPPLS hypothesis. Moreover, the results suggest that CDS spread trajectories belong to a different universality class than, for instance, stock prices.

  1. Stabilization of Taylor-Couette flow due to time-periodic outer cylinder oscillation

    NASA Technical Reports Server (NTRS)

    Murray, B. T.; Mcfadden, G. B.; Coriell, S. R.

    1990-01-01

    The linear stability of circular Couette flow between concentric infinite cylinders is considered for the case when the inner cylinder is rotated at a constant angular velocity and the outer cylinder is driven sinusoidally in time with zero mean rotation. This configuration was studied experimentally by Walsh and Donnelly. The critical Reynolds numbers calculated from linear stability theory agree well with the experimental values, except at large modulation amplitudes and small frequencies. The theoretical values are obtained using Floquet theory implemented in two distinct approaches: a truncated Fourier series representation in time, and a fundamental solution matrix based on a Chebyshev pseudospectral representation in space. For large amplitude, low frequency modulation, the linear eigenfunctions are temporally complex, consisting of a quiescent region followed by rapid change in the perturbed flow velocities.

  2. Time-Perception Network and Default Mode Network Are Associated with Temporal Prediction in a Periodic Motion Task

    PubMed Central

    Carvalho, Fabiana M.; Chaim, Khallil T.; Sanchez, Tiago A.; de Araujo, Draulio B.

    2016-01-01

    The updating of prospective internal models is necessary to accurately predict future observations. Uncertainty-driven internal model updating has been studied using a variety of perceptual paradigms, and have revealed engagement of frontal and parietal areas. In a distinct literature, studies on temporal expectations have also characterized a time-perception network, which relies on temporal orienting of attention. However, the updating of prospective internal models is highly dependent on temporal attention, since temporal attention must be reoriented according to the current environmental demands. In this study, we used functional magnetic resonance imaging (fMRI) to evaluate to what extend the continuous manipulation of temporal prediction would recruit update-related areas and the time-perception network areas. We developed an exogenous temporal task that combines rhythm cueing and time-to-contact principles to generate implicit temporal expectation. Two patterns of motion were created: periodic (simple harmonic oscillation) and non-periodic (harmonic oscillation with variable acceleration). We found that non-periodic motion engaged the exogenous temporal orienting network, which includes the ventral premotor and inferior parietal cortices, and the cerebellum, as well as the presupplementary motor area, which has previously been implicated in internal model updating, and the motion-sensitive area MT+. Interestingly, we found a right-hemisphere preponderance suggesting the engagement of explicit timing mechanisms. We also show that the periodic motion condition, when compared to the non-periodic motion, activated a particular subset of the default-mode network (DMN) midline areas, including the left dorsomedial prefrontal cortex (DMPFC), anterior cingulate cortex (ACC), and bilateral posterior cingulate cortex/precuneus (PCC/PC). It suggests that the DMN plays a role in processing contextually expected information and supports recent evidence that the DMN may

  3. The periodic table of real geometric algebras, bits of space-time, and the Standard Model.

    NASA Astrophysics Data System (ADS)

    Marks, Dennis

    2007-04-01

    Real geometric algebras Rn;s in n dimensions with signature s are isomorphic to algebras of real, complex, or quaternionic matrices R(2^n 2), C(2^n-1 2), or H(2^n-2 2), or of block diagonal matrices ^2R(2^n-1 2) or ^2H(2^n-3 2), for | ( s+3 )8-4 | = 1, 2, 3, 0, or 4, respectively. Only for n = 2 or 4 and s = 0 or 2 is Rn;s isomorphic to real nxn matrices R(n). R2;2 and R2;0 describe the Euclidean plane and the Minkowskian plane. Their direct product, R4;2 = R2;0 R2;2, describes 4-d space-time with signature + + + -- and with dynamical elements (position, spin, momentum, and action) that satisfy the Heisenberg commutation relations. Quantum mechanics emerges naturally. Electromagnetism, described by U(1) C R1;-1, has one time-like coordinate; the weak force, described by SU(2) SO(3) R3;3, has three space-like coordinates. Thus the real algebra of the symmetry group of the electro-weak force is isomorphic to the real algebra of space-time. Finally, R8;2 = R4;0 R4;2 is isomorphic to R(16), into which can be fit three generations of weakly interacting Fermi doublets and three generations of three colors of quarks. Every 8 dimensions thereafter, geometric algebras factor into direct products of R(16), interpreted as a 4-d hexadecimal space-time lattice with four additional internal coordinates for the Standard Model.

  4. VHF radar remote sensing of atmospheric parameters over Taiwan during the time period of Typhoon Wayne

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Tsao, Y. D.; Johnson, D. L.; Chen, A. J.; Lin, C. H.

    1988-01-01

    The VHF radar located at the subtropical and low latitude observing site of Taiwan has been used to observe atmospheric parameters from the troposphere to the middle atmosphere during the time passage of Typhoon Wayne in August 1986. Time-dependent wind velocities with three-dimensional profiles have been plotted by processing the recorded data of the backscattered echo power and the Doppler spectral width of the signal returns from the VHF radar. Propagation characteristics of the gravity waves excited by the enhanced convective motions of Typhoon Wayne have been detected from the Fourier power spectrum analysis of the three-dimensional wind velocities from multiple beams of the VHF radar and their cross-correlation analysis. The density perturbations caused by the propagation of the gravity waves can be calculated from the VHF radar observations. The VHF radar can also be used to detect time-dependent vertical profiles of the liquid water content. The present study shows that the equivalent rainfall rate calculated from the VHF radar is in good agreement with the ground-based measurement of rainfall rate at the same area.

  5. Gender-specific factors associated with shorter sleep duration at age 3 years.

    PubMed

    Plancoulaine, Sabine; Lioret, Sandrine; Regnault, Nolwenn; Heude, Barbara; Charles, Marie-Aline

    2015-12-01

    Total sleep duration has been decreasing among children in the last decades. Short sleep duration (SSD) has been associated with deleterious health consequences, such as excess weight/obesity. Risk factors for SSD have already been studied among school-aged children and adolescents, but inconsistent results have been reported regarding possible gender differences. Studies reporting such relationships are scarce in preschoolers, despite the importance of this period for adopting healthy behaviour. We aimed to investigate factors associated with SSD in 3-year-old boys (n = 546) and girls (n = 482) in a French Mother-Child Cohort (EDEN Study). Children were born between 2003 and 2006 in two French university hospitals. Clinical examinations and parent self-reported questionnaires allowed us to collect sociodemographic (e.g. income, education, family situation, child-minding system), maternal [e.g. body mass index (BMI), parity, depression, breastfeeding duration] and child's characteristics (e.g. gender, birth weight, term, physical activity and TV viewing duration, food consumption, usual sleep time). Sleep duration/24-h period was calculated and SSD was defined as <12 h. Analyses were performed using logistic regression. The mean sleep duration was 12 h 35 ± 56 min, with 91% of the children napping. Patterns of risk factors associated with SSD differed according to gender. In addition to parental presence when falling asleep, short sleep duration was associated strongly positively with high BMI Z-score and TV viewing duration among boys and with familial home child-minding and lower scores on the 'fruits and vegetables' dietary pattern among girls. These results suggest either a patterning of parental behaviours that differs according to gender, or a gender-specific sleep physiology, or both.

  6. L ∞ and L 2 semi-global stabilisation of continuous-time periodic linear systems with bounded controls

    NASA Astrophysics Data System (ADS)

    Zhou, Bin; Hou, Ming-Zhe; Duan, Guang-Ren

    2013-04-01

    This article is concerned with L ∞ and L 2 semi-global stabilisation of continuous-time periodic linear systems with bounded controls. Two problems, namely L ∞ semi-global stabilisation with controls having bounded magnitude and L 2 semi-global stabilisation with controls having bounded energy, are solved based on solutions to a class of periodic Lyapunov differential equations (PLDEs) resulting from the problem of minimal energy control with guaranteed convergence rate. Under the assumption that the open-loop system is (asymptotically) null controllable with constrained controls, periodic feedback are established to solve the concerned problems. The proposed PLDE-based approaches possess the advantage that the resulting controllers are easy to implement since the designers need only to solve a linear differential equation. A numerical example is worked out to illustrate the effectiveness of the proposed approach.

  7. Wavelets, period-doubling, and time-frequency localization with application to organization of convection over the tropical western Pacific

    NASA Technical Reports Server (NTRS)

    Weng, Hengyi; Lau, K.-M.

    1994-01-01

    In this paper, preliminary results in using orthogonal and continuous wavelet transform (WT) to identify period doubling and time-frequency localization in both synthetic and real data are presented. First, the Haar WT is applied to synthetic time series derived from a simple nonlinear dynamical system- a first-order quadratic difference equation. Second, the complex Morlet WT is used to study the time-frequency localization of tropical convection based on a high-resolution Japanese Geostationary Meteorological Satellite infrared (IR) radiance dataset. The Haar WT of the synthetic time series indicates the presence and distinct separation of multiple frequencies in a period-doubling sequence. The period-doubling process generates a multiplicity of intermediate frequencies, which are manifested in the nonuniformity in time with respect to the phase of oscillations in the lower frequencies. Wavelet transform also enables the detection of extremely weak signals in high-order subharmonics resulting from the period-doubling bifurcations. These signals are either undetected or considered statistically insignificant by traditional Fourier analysis. The Morlet WT of the IR radiance dataset indicates the presence of multiple timescales, which are localized in both frequency and time. There are two regimes in the variation of IR radiance, corresponding to the wet and dry periods. Multiple timescales, ranging from semidiurnal, diurnal, synoptic, to intraseasonal with embedding structures, are active in the wet regime. In particular, synoptic variability is more prominent during the wet phase of an intensive intraseasonal cycle. These are not only consistent with, but also show more details than, previous findings by using other techniques. The phase-locking relationships among the oscillations with different time-scales suggest that both synoptic and intraseasonal variations may be mixed oscillations due to the interaction of self-excited oscillations in the tropical

  8. A multivariate time-frequency method to characterize the influence of respiration over heart period and arterial pressure

    NASA Astrophysics Data System (ADS)

    Orini, Michele; Bailón, Raquel; Laguna, Pablo; Mainardi, Luca T.; Barbieri, Riccardo

    2012-12-01

    Respiratory activity introduces oscillations both in arterial pressure and heart period, through mechanical and autonomic mechanisms. Respiration, arterial pressure, and heart period are, generally, non-stationary processes and the interactions between them are dynamic. In this study we present a methodology to robustly estimate the time course of cross spectral indices to characterize dynamic interactions between respiratory oscillations of heart period and blood pressure, as well as their interactions with respiratory activity. Time-frequency distributions belonging to Cohen's class are used to estimate time-frequency (TF) representations of coherence, partial coherence and phase difference. The characterization is based on the estimation of the time course of cross spectral indices estimated in specific TF regions around the respiratory frequency. We used this methodology to describe the interactions between respiration, heart period variability (HPV) and systolic arterial pressure variability (SAPV) during tilt table test with both spontaneous and controlled respiratory patterns. The effect of selective autonomic blockade was also studied. Results suggest the presence of common underling mechanisms of regulation between cardiovascular signals, whose interactions are time-varying. SAPV changes followed respiratory flow both in supine and standing positions and even after selective autonomic blockade. During head-up tilt, phase differences between respiration and SAPV increased. Phase differences between respiration and HPV were comparable to those between respiration and SAPV during supine position, and significantly increased during standing. As a result, respiratory oscillations in SAPV preceded respiratory oscillations in HPV during standing. Partial coherence was the most sensitive index to orthostatic stress. Phase difference estimates were consistent among spontaneous and controlled breathing patterns, whereas coherence was higher in spontaneous breathing

  9. Frequency decoding of periodically timed action potentials through distinct activity patterns in a random neural network

    NASA Astrophysics Data System (ADS)

    Reichenbach, Tobias; Hudspeth, A. J.

    2012-11-01

    Frequency discrimination is a fundamental task of the auditory system. The mammalian inner ear, or cochlea, provides a place code in which different frequencies are detected at different spatial locations. However, a temporal code based on spike timing is also available: action potentials evoked in an auditory-nerve fiber by a low-frequency tone occur at a preferred phase of the stimulus—they exhibit phase locking—and thus provide temporal information about the tone's frequency. Humans employ this temporal information for discrimination of low frequencies. How might such temporal information be read out in the brain? Here we employ statistical and numerical methods to demonstrate that recurrent random neural networks in which connections between neurons introduce characteristic time delays, and in which neurons require temporally coinciding inputs for spike initiation, can perform sharp frequency discrimination when stimulated with phase-locked inputs. Although the frequency resolution achieved by such networks is limited by the noise in phase locking, the resolution for realistic values reaches the tiny frequency difference of 0.2% that has been measured in humans.

  10. The Evolution of Cloud Features on Neptune over a 20-day time period

    NASA Astrophysics Data System (ADS)

    Martin, S. C.; Roe, H.; de Pater, I.; Macintosh, B.; Gibbard, S.; Max, C. E.; Gavel, D.; Brown, M.; Ghez, A.

    2000-10-01

    Near-infrared images of Neptune were taken with SCAM, the slit-viewing camera of the AO/NIRSPEC system at the 10-m W.M. Keck II telescope, on 2000 June 8,17,18,22,23 and 29 UT. Observations with broad-band filter Nirspec-5 [1.61 micron], Nirspec-6 [1.93 micron], and K' [2.12 micron], and several narrow-band filters between 1.279 and 1.702 microns are compared to determine the temporal evolution of cloud features over the 20-day period. These images taken with the Keck Adaptive Optics system are spectacular, revealing narrow zonal bands at 3-4 degree latitude spacings within bright regions and near the equator. There are three regions of latitude that contain bright features along zonal bands. The dimmest of these bright regions is located in the Northern hemisphere and extends from 20 deg N to 40 deg N. The remaining two bright regions are located in the Southern hemisphere extending from 20 deg S to 50 deg S, and from 60 deg S to 70 deg S. The region near the South pole (a recently quiet location) contains a bright teardrop-shaped feature which may be related to the Westerly jet observed by Voyager and reported by Sanjay et.al. (Journal of Geophysical Research, vol.6, pp. 18941-18960, 1991) at a similar latitude. This research was supported in part by the STC Program of the National Science Foundation under Agreement No. AST-9876783, and in part under the auspices of the US Department of Energy at Lawrence Livermore National Laboratory, Univ. of Calif. under contract No. W-7405-Eng-48. Data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation.

  11. Comparison of arbitrary definitions of circadian time periods with those determined by wrist actigraphy in analysis of ABPM data.

    PubMed

    Eissa, M A; Yetman, R J; Poffenbarger, T; Portman, R J

    1999-11-01

    Determining blood pressure (BP) values at different daily time periods is a well recognised measure to assess the risk of end-organ damage. However, the use of various definitions of these periods, eg, day vs night, sleep vs wake or arbitrary definitions, makes clinical decisions based on available data difficult. In the present study, we compared BP loads in actual sleep-wake periods to default day-night definition provided by the ambulatory BP monitoring (ABPM) software (day 06.00 to 22.00; night 22.00 to 06.00) as well as to an arbitrary definition of sleep-wake periods in children published in Soergel et al (J Pediatr 1997; 130: 178-184)1 (awake 08.00 to 20.00 and sleep 00.00 to 06.00. We used an actigraphy, an accelerometer, to define the actual sleep-wake periods in 46 patients with essential hypertension who are on various treatment regimens. BP data was obtained by using Spacelabs 90207 monitors for a full 24 h. There were significant differences between actual sleep-wake and default definition for BP load. No similar finding was noted when arbitrary definition was used. The proportion of hypertensives was not significantly different when default and arbitrary definitions were used. Classification of dippers and non-dippers is greatly affected by the definition of sleep interval using the default method. Although some of the misclassifications were not statistically significant, their clinical importance must be considered. Determination of sleep and wake periods for analysis of ABPM data should be based on careful determination of actual periods. Using other definitions may not provide complete information or accommodate for individual variation.

  12. Comparison of arbitrary definitions of circadian time periods with those determined by wrist actigraphy in analysis of ABPM data.

    PubMed

    Eissa, M A; Yetman, R J; Poffenbarger, T; Portman, R J

    1999-07-01

    Determining blood pressure (BP) values at different daily time periods is a well recognised measure to assess the risk of end-organ damage. However, the use of various definitions of these periods, eg, day vs night, sleep vs wake or arbitrary definitions, makes clinical decisions based on available data difficult. In the present study, we compared BP loads in actual sleep-wake periods to default day-night definition provided by the ambulatory BP monitoring (ABPM) software (day 06.00-22.00; night 22.00-06.00) as well as to an arbitrary definition of sleep-wake periods in children published in Journal of Pediatrics (Soergel et al, 1997) (awake 08.00-20:00 and sleep 00.00-06.00). We used an actigraph, an accelerometer, to define the actual sleep-wake periods in 46 patients with essential hypertension who are on various treatment regimens. BP data were obtained by using Spacelabs 90207 monitors for a full 24 hours. There were significant differences between actual sleep-wake and default definition for BP load. No similar findings were noted when arbitrary definition was used. The proportion of hypertensives was not significantly different when default and arbitrary definitions were used. Classification of dippers and non-dippers is greatly affected by the definition of sleep interval using the default method. Although some of the misclassifications were not statistically significant, their clinical importance must be considered. Determination of sleep and wake periods for analysis of ABPM data should be based on careful determination of actual periods. Using other definitions may not provide complete information or accommodate for individual variation.

  13. Time-scale calibration by U-Pb geochronology: Examples from the Triassic Period

    NASA Astrophysics Data System (ADS)

    Mundil, R.

    2009-05-01

    U-Pb zircon geochronology, pioneered by Tom Krogh, is a cornerstone for the calibration of the time scale. Before Krogh's innovations, U-Pb geochronology was essentially limited by laboratory blank Pb (typically hundreds of nanograms) inherent in the then existing zircon dissolution and purification methods. The introduction of high pressure HF dissolution combined with miniature ion exchange columns (1) reduced the blank by orders of magnitude and allowed mass-spectrometric analyses of minute amounts of material (picograms of Pb and U). Krogh also recognized the need for minimizing the effects of Pb loss, and the introduction of the air-abrasion technique was the method of choice for two decades (2), until the development of the combined annealing and chemical abrasion technique resulted in essentially closed system zircons (3). These are the prerequisite for obtaining precise (permil-level) and accurate radio-isotopic ages of individual zircons contained in primary volcanic ash deposits, which are primary targets for the calibration of the time scale if they occur within fossil bearing sediments. A prime example is the calibration of the Triassic time scale which improved significantly using these techniques. The ages for the base and the top of the Triassic are constrained by U-Pb ages to 252.3 (4) and 201.5 Ma (5), respectively. These dates also constrain the ages of major extinction events at the Permian-Triassic and Triassic-Jurassic boundaries, and are statistically indistinguishable from ages obtained for the Siberian Traps and volcanic products from the Central Atlantic Magmatic Province, respectively, suggesting a causal link. Ages for these continental volcanics, however, are mostly from the K-Ar (40Ar/39Ar) system which requires accounting and correcting for a systematic bias of ca 1 % between U-Pb and 40Ar/39Ar isotopic ages (the 40Ar/39Ar ages being younger) (6). Robust U-Pb age constraints also exist for the Induan- Olenekian boundary (251.2 Ma, (7

  14. Evaluation of the appropriate time period between sampling and analyzing for automated urinalysis

    PubMed Central

    Dolscheid-Pommerich, Ramona C.; Klarmann-Schulz, Ute; Conrad, Rupert; Stoffel-Wagner, Birgit; Zur, Berndt

    2016-01-01

    Introduction Preanalytical specifications for urinalysis must be strictly adhered to avoid false interpretations. Aim of the present study is to examine whether the preanalytical factor ‘time point of analysis’ significantly influences stability of urine samples for urine particle and dipstick analysis. Materials and methods In 321 pathological spontaneous urine samples, urine dipstick (Urisys™2400, Combur-10-Test™strips, Roche Diagnostics, Mannheim, Germany) and particle analysis (UF-1000 i™, Sysmex, Norderstedt, Germany) were performed within 90 min, 120 min and 240 min after urine collection. Results For urine particle analysis, a significant increase in conductivity (120 vs. 90 min: P < 0.001, 240 vs. 90 min: P < 0.001) and a significant decrease in WBC (120 vs. 90 min P < 0.001, 240 vs. 90 min P < 0.001), RBC (120 vs. 90 min P < 0.001, 240 vs. 90 min P < 0.001), casts (120 vs. 90 min P < 0.001, 240 vs. 90 min P < 0.001) and epithelial cells (120 vs. 90 min P = 0.610, 240 vs. 90 min P = 0.041) were found. There were no significant changes for bacteria. Regarding urine dipstick analysis, misclassification rates between measurements were significant for pH (120 vs. 90 min P < 0.001, 240 vs. 90 min P < 0.001), leukocytes (120 vs. 90 min P < 0.001, 240 vs. 90 min P < 0.001), nitrite (120 vs. 90 min P < 0.001, 240 vs. 90 min P < 0.001), protein (120 vs. 90 min P < 0.001, 240 vs. 90 min P<0.001), ketone (120 vs. 90 min P < 0.001, 240 vs. 90 min P < 0.001), blood (120 vs. 90 min P < 0.001, 240 vs. 90 min P < 0.001), specific gravity (120 vs. 90 min P < 0.001, 240 vs. 90 min P < 0.001) and urobilinogen (120 vs. 90 min, P = 0.031). Misclassification rates were not significant for glucose and bilirubin. Conclusion Most parameters critically depend on the time window between sampling and analysis. Our study stresses the importance of adherence to early time points in urinalysis (within 90 min). PMID:26981022

  15. A Test Model for Fluctuation-Dissipation Theorems with Time Periodic Statistics (PREPRINT)

    DTIC Science & Technology

    2010-03-09

    Cov(u2(, u ∗ 2) ∂γ2 = − ∫ t −∞ ∫ t −∞ (2t− s− r)e−γ2(2t−s−r) ( 〈ψ(s, t)ψ(r, t)〉 − 〈ψ(s, t)〉〈ψ(r, t)〉 ) f2(s)f2(r)dsdr, (88) References [1] R. Abramov ...Short-time linear response with reduced-rank tangent map. Chinese Annals of Mathematics, Series B., 30:447–462, 2009. [2] R. Abramov and A.J. Majda... Abramov and A.J. Majda. New approximations and tests of linear fluctuation-response for chaotic nonlinear forced-dissipative dynamical sys- tems. J

  16. An insight into the behaviour of oscillators with a periodically piecewise-defined time-varying mass

    NASA Astrophysics Data System (ADS)

    Zukovic, Miodrag; Kovacic, Ivana

    2017-01-01

    Free vibrations of a linear, single-degree-of-freedom oscillator with a periodic piecewise-defined time-varying mass are studied. Two different cases of this variation are investigated: first, the mass increases and then decreases linearly in time, i.e. it changes triangularly, and the second, when the mass changes trapezoidically, which, unlike the previous case, includes the period when it remains constant. Exact solutions for motion are obtained analytically directly from the equations of motion, and the criteria of stability are derived and used to plot stability charts for different system parameters. In addition, the transformed equation of motion is utilized in conjunction with harmonic balancing to derive approximate analytical expressions for the boundaries of the first and second instability region.

  17. The strain effect on the Dirac electrons tunneling through the time-periodic scalar and vector barriers

    NASA Astrophysics Data System (ADS)

    Yan, Weixian

    2017-01-01

    The tunneling of the massless and massive Dirac particle through the strained barriers driven by the time-periodic scalar potentials and the static vector potentials is investigated, where the interrelationships among the strain, the incidence angle, the dynamic scalar potential, the magnetic field and the transmission of the Dirac particle have been discussed. In either massless or massive case, the intersection angle between the obliquely incident Dirac particle and strain determines the extent of deviation of the tunneling profiles from the strainless case. The time-periodic scalar potentials can enhance the capability of the Dirac particle to surmount the energy gap induced by the mass, reflecting quantum nature of the photon-assisted tunneling. When the magnetic field is switched on, the transmission overall presents a remarkably different profile, and decreases with the increase of the magnetic fields due to the conservation of the transverse momentum, which reduces the number of the side-band channels for tunneling.

  18. Stability of small-amplitude periodic solutions near Hopf bifurcations in time-delayed fully-connected PLL networks

    NASA Astrophysics Data System (ADS)

    Ferruzzo Correa, Diego P.; Bueno, Átila M.; Castilho Piqueira, José R.

    2017-04-01

    In this paper we investigate stability conditions for small-amplitude periodic solutions emerging near symmetry-preserving Hopf bifurcations in a time-delayed fully-connected N-node PLL network. The study of this type of systems which includes the time delay between connections has attracted much attention among researchers mainly because the delayed coupling between nodes emerges almost naturally in mathematical modeling in many areas of science such as neurobiology, population dynamics, physiology and engineering. In a previous work it has been shown that symmetry breaking and symmetry preserving Hopf bifurcations can emerge in the parameter space. We analyze the stability along branches of periodic solutions near fully-synchronized Hopf bifurcations in the fixed-point space, based on the reduction of the infinite-dimensional space onto a two-dimensional center manifold in normal form. Numerical results are also presented in order to confirm our analytical results.

  19. On the periodic dynamics of a class of time-varying delayed neural networks via differential inclusions.

    PubMed

    Cai, Zuowei; Huang, Lihong; Guo, Zhenyuan; Chen, Xiaoyan

    2012-09-01

    This paper investigates the periodic dynamics of a general class of time-varying delayed neural networks with discontinuous right-hand sides. By employing the topological degree theory in set-valued analysis, differential inclusions theory and Lyapunov-like approach, we perform a thorough analysis of the existence, uniqueness and global exponential stability of the periodic solution for the neural networks. Especially, some sufficient conditions are derived to guarantee the existence, uniqueness and global exponential stability of the equilibrium point for the autonomous systems corresponding to the non-autonomous neural networks. Furthermore, the global convergence of the output and the convergence in finite time of the state are also discussed. Without assuming the boundedness or monotonicity of the discontinuous neuron activation functions, the obtained results improve and extend previous works on discontinuous or continuous neural network dynamical systems. Finally, two numerical examples are provided to show the applicability and effectiveness of our main results.

  20. Hydrodynamics, temperature/salinity variability and residence time in the Chilika lagoon during dry and wet period: Measurement and modeling

    NASA Astrophysics Data System (ADS)

    Mahanty, M. M.; Mohanty, P. K.; Pattnaik, A. K.; Panda, U. S.; Pradhan, S.; Samal, R. N.

    2016-08-01

    This paper investigated the hydrodynamics, spatio-temporal variability of temperature/salinity and the residence time of tracer concentrations in a largest brackish water coastal lagoon in Asia, namely the Chilika lagoon, India. An integrated approach combined the measurement and 2D hydrodynamic-advection/dispersion model is used to simulate circulation and temperature/salinity, and estimated the water residence time in lagoon under different forcing mechanisms, such as tide, wind and freshwater discharge during the dry and wet periods. Water circulation inside the lagoon is simulated when wind is included with the tide only forcing during dry period, and freshwater influx is included with the tide and wind forcing during wet period. Under the realistic forcing conditions, the computed temporal variability of water temperature and salinity are well correlated with the measurements in both the periods. The spatial variations of water temperature within the lagoon is influenced by the meteorological conditions, tide and freshwater influx as well as the shallowness of the lagoon, whereas the salinity is spatially controlled by the freshwater influx from the riverine system and seawater intrusion through the tidal inlets. The numerical model results show that in the Chilika lagoon tidal and river influx affect significantly the residence time spatially, and is site specific. The residence time varies from values of 4-5 days in the outer channel (OC) and 132 days at the northern sector (NS) in the main body of lagoon. The current study represents a first attempt to use a combined model approach, which is therefore, a useful tool to support the ecological implication of the lagoon ecosystem.

  1. On the Frequency of Additional Planets in Short Period Hot Jupiter Systems from Transit Timing Variations

    NASA Astrophysics Data System (ADS)

    Dittmann, Jason; Close, L.; Scuderi, L.

    2011-05-01

    The large number of hot Jupiter planets allows one to probe these systems for additional unseen planets via transit timing variations (TTVs). Even relatively small terrestrial planets, when placed in an energetically favorable mean motion resonance (MMR), can cause detectable TTVs with an amplitude of several minutes (Holman and Murray 2005, Agol et al. 2005). In an effort to discover and characterize such companions, we have embarked on a systematic study of known transiting hot Jupiters, utilizing the 1.55 meter Kuiper telescope on Mt. Bigelow to measure multiple individual transits in an observing season to within 30 second precision, and constrain the nature of any planetary companions. Here, we present current and preliminary results on this study, and show that the systems HAT-P-5, HAT- P-6, HAT-P-8, HAT-P-9, WASP-11/HAT-P-10, HAT-P-11, TrES-2, and WASP-10 do not contain small mass companions in MMRs, or moderate mass companions in close enough proximity to induce TTVs on the order of 1.5 minutes.

  2. Need for desiccant in containers exposed to atmospheric conditions for long periods of time

    SciTech Connect

    Mead, K.E.

    1981-11-01

    Current component and system designs are required to perform satisfactorily up to 25 years. A maximum leak rate of 1 x 10/sup -6/ cc(STP) helium/sec-atm is a frequent requirement for component containers. Calculations show that undesiccated component containers continuously exposed to 50% relative humidity at 20/sup 0/C and having an internal free volume of less than 300 cc and the above leak rate will allow the internal dew point to rise enough for potential liquid condensation in less than four years. For the same vapor pressure differential, the moisture permeation rate through one linear inch of silicone o-ring is 750 times as fast as moisture enters a welded container whose leak rate is 1 x 10/sup -6/ cc(STP) helium/sec-atm. For ethylene propylene o-ring material this ratio is about 13. These values correspond to the ratios of the quantities of desiccant required to maintain an acceptable dew point temperature when the moisture capacity of the free volume is not included. Charts are provided for estimating the amount of desiccant required for helium leak tested containers and for containers sealed with elastomeric o-rings.

  3. Maintaining high precision of isotope ratio analysis over extended periods of time.

    PubMed

    Brand, Willi A

    2009-06-01

    Stable isotope ratios are reliable and long lasting process tracers. In order to compare data from different locations or different sampling times at a high level of precision, a measurement strategy must include reliable traceability to an international stable isotope scale via a reference material (RM). Since these international RMs are available in low quantities only, we have developed our own analysis schemes involving laboratory working RM. In addition, quality assurance RMs are used to control the long-term performance of the delta-value assignments. The analysis schemes allow the construction of quality assurance performance charts over years of operation. In this contribution, the performance of three typical techniques established in IsoLab at the MPI-BGC in Jena is discussed. The techniques are (1) isotope ratio mass spectrometry with an elemental analyser for delta(15)N and delta(13)C analysis of bulk (organic) material, (2) high precision delta(13)C and delta(18)O analysis of CO(2) in clean-air samples, and (3) stable isotope analysis of water samples using a high-temperature reaction with carbon. In addition, reference strategies on a laser ablation system for high spatial resolution delta(13)C analysis in tree rings is exemplified briefly.

  4. Periodicity analysis of δ18O in precipitation over Central Europe: Time-frequency considerations of the isotopic 'temperature' effect

    NASA Astrophysics Data System (ADS)

    Salamalikis, V.; Argiriou, A. A.; Dotsika, E.

    2016-03-01

    In this paper the periodic patterns of the isotopic composition of precipitation (δ18O) for 22 stations located around Central Europe are investigated through sinusoidal models and wavelet analysis over a 23 years period (1980/01-2002/12). The seasonal distribution of δ18O follows the temporal variability of air temperature providing seasonal amplitudes ranging from 0.94‰ to 4.47‰; the monthly isotopic maximum is observed in July. The isotopic amplitude reflects the geographical dependencies of the isotopic composition of precipitation providing higher values when moving inland. In order to describe the dominant oscillation modes included in δ18O time series, the Morlet Continuous Wavelet Transform is evaluated. The main periodicity is represented at 12-months (annual periodicity) where the wavelet power is mainly concentrated. Stations (i.e. Cuxhaven, Trier, etc.) with limited seasonal isotopic effect provide sparse wavelet power areas at the annual periodicity mode explaining the fact that precipitation has a complex isotopic fingerprint that cannot be examined solely by the seasonality effect. Since temperature is the main contributor of the isotopic variability in mid-latitudes, the isotope-temperature effect is also investigated. The isotope-temperature slope ranges from 0.11‰/°C to 0.47‰/°C with steeper values observed at the southernmost stations of the study area. Bivariate wavelet analysis is applied in order to determine the correlation and the slope of the δ18O - temperature relationship over the time-frequency plane. High coherencies are detected at the annual periodicity mode. The time-frequency slope is calculated at the annual periodicity mode ranging from 0.45‰/°C to 0.83‰/°C with higher values at stations that show a more distinguishable seasonal isotopic behavior. Generally the slope fluctuates around a mean value but in certain cases (sites with low seasonal effect) abrupt slope changes are derived and the slope becomes

  5. Impacts of 3 years of elevated atmospheric CO2 on rhizosphere carbon flow and microbial community dynamics.

    PubMed

    Drigo, Barbara; Kowalchuk, George A; Knapp, Brigitte A; Pijl, Agata S; Boschker, Henricus T S; van Veen, Johannes A

    2013-02-01

    Carbon (C) uptake by terrestrial ecosystems represents an important option for partially mitigating anthropogenic CO2 emissions. Short-term atmospheric elevated CO2 exposure has been shown to create major shifts in C flow routes and diversity of the active soil-borne microbial community. Long-term increases in CO2 have been hypothesized to have subtle effects due to the potential adaptation of soil microorganism to the increased flow of organic C. Here, we studied the effects of prolonged elevated atmospheric CO2 exposure on microbial C flow and microbial communities in the rhizosphere. Carex arenaria (a nonmycorrhizal plant species) and Festuca rubra (a mycorrhizal plant species) were grown at defined atmospheric conditions differing in CO2 concentration (350 and 700 ppm) for 3 years. During this period, C flow was assessed repeatedly (after 6 months, 1, 2, and 3 years) by (13) C pulse-chase experiments, and label was tracked through the rhizosphere bacterial, general fungal, and arbuscular mycorrhizal fungal (AMF) communities. Fatty acid biomarker analyses and RNA-stable isotope probing (RNA-SIP), in combination with real-time PCR and PCR-DGGE, were used to examine microbial community dynamics and abundance. Throughout the experiment the influence of elevated CO2 was highly plant dependent, with the mycorrhizal plant exerting a greater influence on both bacterial and fungal communities. Biomarker data confirmed that rhizodeposited C was first processed by AMF and subsequently transferred to bacterial and fungal communities in the rhizosphere soil. Over the course of 3 years, elevated CO2 caused a continuous increase in the (13) C enrichment retained in AMF and an increasing delay in the transfer of C to the bacterial community. These results show that, not only do elevated atmospheric CO2 conditions induce changes in rhizosphere C flow and dynamics but also continue to develop over multiple seasons, thereby affecting terrestrial ecosystems C utilization processes.

  6. Impact of a 3-year pet management program on pet population and owner's perception.

    PubMed

    Dias Costa, Esther; Martins, Camila Marinelli; Cunha, Graziela Ribeiro; Catapan, Dariane Cristina; Ferreira, Fernando; Oliveira, Simone Tostes; Garcia, Rita de Cassia Maria; Biondo, Alexander Welker

    2017-04-01

    Although pet population management programs have been established worldwide, few reports on program evaluation have been carried out to date. Accordingly, a 3-year longitudinal study has been carried out in a 4000 household neighborhood located within the metropolitan area of Curitiba, the eighth most populated city of Brazil. Visits were conducted and questionnaires completed to estimate and characterize the local pet population (animal sex, reproductive and vaccination status, street access). Care provided by owners, community perception on stray dog management and the possible changes were compared in these variables over time (2010 and 2013) were evaluated, after the establishment of a city pet population management program. In addition, associations between having children, owning dogs and cats, responsible pet ownership education and owner's perception on stray dogs were statistically tested. A total of 354/4000 (8.9%) household families were interviewed in 2010 and 70/354 (19.8%) of the same families again in 2013. No significant changes were found in overall number of dogs and cats and average pet age, animal care and owner's perception on stray dogs following the 3-year population management program. In 2010, an average of 1.6 dogs and 0.3 cats were found per family, with slightly more females (51.3% dogs and 51.1% cats), adults (4.0±3.5years for dogs and 2.1±2.4 for cats), intact (not neutered; 94.2% dogs and 84.0% cats) and lacking regular visit to veterinarian (71.6%). Although more families (53.1%) had children under 12 years old, no association was found between having children and having dogs and cats. Questionnaires revealed that owners perceived neutering/spaying to be the best pet population control method (42.4%), with "society" (50%) and "government" (49.4%) as responsible for pet population management. A significant positive association has been found between education level and the best way to control stray dogs (p=0.03), between having dogs

  7. Methods for Developing Evidence Reviews in Short Periods of Time: A Scoping Review

    PubMed Central

    Abou-Setta, Ahmed M.; Jeyaraman, Maya; Attia, Abdelhamid; Al-Inany, Hesham G.; Ferri, Mauricio; Ansari, Mohammed T.; Garritty, Chantelle M.; Bond, Kenneth; Norris, Susan L.

    2016-01-01

    Introduction Rapid reviews (RR), using abbreviated systematic review (SR) methods, are becoming more popular among decision-makers. This World Health Organization commissioned study sought to summarize RR methods, identify differences, and highlight potential biases between RR and SR. Methods Review of RR methods (Key Question 1 [KQ1]), meta-epidemiologic studies comparing reliability/ validity of RR and SR methods (KQ2), and their potential associated biases (KQ3). We searched Medline, EMBASE, Cochrane Library, grey literature, and checked reference lists, used personal contacts, and crowdsourcing (e.g. email listservs). Selection and data extraction was conducted by one reviewer (KQ1) or two reviewers independently (KQ2-3). Results Across all KQs, we identified 42,743 citations through the literature searches. KQ1: RR methods from 29 organizations were reviewed. There was no consensus on which aspects of the SR process to abbreviate. KQ2: Studies comparing the conclusions of RR and SR (n = 9) found them to be generally similar. Where major differences were identified, it was attributed to the inclusion of evidence from different sources (e.g. searching different databases or including different study designs). KQ3: Potential biases introduced into the review process were well-identified although not necessarily supported by empirical evidence, and focused mainly on selective outcome reporting and publication biases. Conclusion RR approaches are context and organization specific. Existing comparative evidence has found similar conclusions derived from RR and SR, but there is a lack of evidence comparing the potential of bias in both evidence synthesis approaches. Further research and decision aids are needed to help decision makers and reviewers balance the benefits of providing timely evidence with the potential for biased findings. PMID:27930662

  8. Identifying Thermally Challenging Landscapes and Time Periods for Wildlife Using Remote Sensing

    NASA Astrophysics Data System (ADS)

    Albright, T. P.; Pidgeon, A.; Radeloff, V.; Wardlow, B.

    2011-12-01

    Recent events and climate model outputs indicate an increase in the occurrence and magnitude of heat waves and other high temperature events in many locations. Temperatures at the land surface may be much higher than air temperatures making this a particularly relevant consideration for animals that nest, forage, or seek refuge at or near the ground. Often associated with heat waves are prolonged and/or rapid onset drought events, which can combine to place stress on vegetation and animals. In order to assess the influence of heat waves and drought on communities of birds, we developed statistical models between avian abundance and species richness data collected by volunteer observers as part of the North American Breeding Bird Survey and a suite of precipitation and temperature metrics. We used station data, gridded standardized precipitation indices, and remotely sensed vegetation indices, and developed an index of accumulated temperature exceedance using time series MODIS land surface temperature (LST) products. Mixed effects models accounting for nuisance factors and temporal autocorrelation revealed that LST was among the strongest predictors of same year and following-year avian abundance. In particular, declines in abundance were largest and most common among ground-nesting birds and long-distance migrants in the US Southwest. In cooler regions, high LST exceedances were sometimes associated with increases in abundance. Because these results do not indicate whether dispersal, reproductive effort, or mortality explain the changes, one area of current research focuses on identifying demographic mechanisms and population consequences of such responses. A second area of active research focuses on using LST data in conjunction with digital elevation models and derivatives and dense networks of ground-level observations to produce physiologically-relevant indicators of thermally stressful conditions for birds and other animals.

  9. Blowout Fracture in a 3-Year-Old

    PubMed Central

    Pluijmers, Britt I.; Koudstaal, Maarten J.; Paridaens, Dion; van der Wal, Karel G.H.

    2013-01-01

    A 3-year-old patient was referred to the oral and maxillofacial department with a fracture of the orbital floor. Due to the lack of clinical symptoms, a conservative approach was chosen. After 3 weeks, an enophthalmos developed. The orbital floor reconstruction was successfully performed through a transconjunctival approach. This case highlights the rarity of pure blowout fractures in young children. The specific presentation and diagnostics of orbital floor fractures in children and the related surgical planning and intervention are discussed. PMID:24436749

  10. Pulmonary nocardiosis in a 3-year-old child

    PubMed Central

    Holdaway, M. D.; Kennedy, J.; Ashcroft, T.; Kay-Butler, J. J.

    1967-01-01

    Until 1960, 179 cases of infection with Nocardia asteroides had been described in the world literature. Seventeen cases in children were reported by 1963. The organism is a common saprophyte in nature with probably a world-wide distribution. Infection can be primary but is more common in patients with underlying malignancy, auto-immune disease or preceding tuberculosis. Sulphonamides, particularly sulphadiazine, are the drugs of choice in treatment; the value of antibiotics is less clearly established. The indications for surgical treatment have not yet been defined. We record a further case of primary pulmonary nocardiosis in a 3-year-old child. Images PMID:6035802

  11. Age-Period-Cohort Analysis of 1990–2003 Incidence Time Trends of Childhood Diabetes in Italy

    PubMed Central

    Bruno, Graziella; Maule, Milena; Merletti, Franco; Novelli, Giulia; Falorni, Alberto; Iannilli, Antonio; Iughetti, Lorenzo; Altobelli, Emma; d'Annunzio, Giuseppe; Piffer, Silvano; Pozzilli, Paolo; Iafusco, Dario; Songini, Marco; Roncarolo, Federico; Toni, Sonia; Carle, Flavia; Cherubini, Valentino

    2010-01-01

    OBJECTIVE To investigate age-period-cohort effects on the temporal trend of type 1 diabetes in children age 0–14 years in Italian registries. RESEARCH DESIGN AND METHODS This report is based on 5,180 incident cases in the period 1990–2003 from the Registry for Type 1 Diabetes Mellitus in Italy (RIDI). Multilevel (random intercept) Poisson regression models were used to model the effects of sex, age, calendar time, and birth cohorts on temporal trends, taking into account the registry-level variance component. RESULTS The incidence rate was 12.26 per 100,000 person-years and significantly higher in boys (13.13 [95% CI 12.66–13.62]) than in girls (11.35 [10.90–11.82]). Large geographical variations in incidence within Italy were evident; incidence was highest in Sardinia, intermediate in Central-Southern Italy, and high in Northern Italy, particularly in the Trento Province, where the incidence rate was 18.67 per 100,000 person-years. An increasing temporal trend was evident (2.94% per year [95% CI 2.22–3.67]). With respect to the calendar period 1990–1992, the incidence rates increased linearly by 15, 27, 35, and 40% in the following time periods (P for trend < 0.001). With respect to the 1987–1993 birth cohort, the incidence rate ratio increased approximately linearly from 0.63 (95% CI 0.54–0.73) in the 1975–1981 cohort to 1.38 (1.06–1.80) in the 1999–2003 cohort. The best model, however, included sex, age, and a linear time trend (drift). CONCLUSIONS Large geographical variations and an increasing temporal trend in diabetes incidence are evident among type 1 diabetic children in Italy. Age-period-cohort analysis shows that the variation over time has a linear component that cannot be ascribed to either the calendar period or the birth cohort. PMID:20566665

  12. Food insufficiency and women's mental health: findings from a 3-year panel of welfare recipients.

    PubMed

    Heflin, Colleen M; Siefert, Kristine; Williams, David R

    2005-11-01

    Household food insufficiency is a significant problem in the United States, and has been associated with poor outcomes on mental health indicators among low-income women. However, it is difficult to disentangle the mental health consequences of household food insufficiency from poverty and other shared risk factors. Drawing on theories of the social production of health and disease, research evidence linking food insufficiency with poor mental health, and high rates of food insufficiency among welfare recipients, we examined whether a change in household food insufficiency is associated with a change in women's self-reported mental health in a sample of current and recent welfare recipients over a 3-year period of time, controlling for common risk factors. Data were obtained from a prospective survey of women who were welfare recipients in an urban Michigan county in February 1997 (n=753). We estimated fixed effect models for changes in mental health status that make use of information on household food insufficiency gathered in the fall of 1997, 1998, and 1999. The relationship between household food insufficiency and respondents' meeting the diagnostic screening criteria for major depression remained highly significant even when controlling for factors known to confer increased risk of depression and time invariant unobserved heterogeneity. These findings add to growing evidence that household food insufficiency has potentially serious consequences for low-income women's mental health. If confirmed by further research, they suggest that the public health burden of depression in welfare recipients and other low-income women could be reduced by policy-level interventions to reduce their exposure to household food insufficiency.

  13. Chiral tunneling modulated by a time-periodic potential on the surface states of a topological insulator

    PubMed Central

    Li, Yuan; Jalil, Mansoor B. A.; Tan, S. G.; Zhao, W.; Bai, R.; Zhou, G. H.

    2014-01-01

    Time-periodic perturbation can be used to modify the transport properties of the surface states of topological insulators, specifically their chiral tunneling property. Using the scattering matrix method, we study the tunneling transmission of the surface states of a topological insulator under the influence of a time-dependent potential and finite gate bias voltage. It is found that perfect transmission is obtained for electrons which are injected normally into the time-periodic potential region in the absence of any bias voltage. However, this signature of Klein tunneling is destroyed when a bias voltage is applied, with the transmission probability of normally incident electrons decreasing with increasing gate bias voltage. Likewise, the overall conductance of the system decreases significantly when a gate bias voltage is applied. The characteristic left-handed helicity of the transmitted spin polarization is also broken by the finite gate bias voltage. In addition, the time-dependent potential modifies the large-angle transmission profile, which exhibits an oscillatory or resonance-like behavior. Finally, time-dependent transport modes (with oscillating potential in the THz frequency) can result in enhanced overall conductance, irrespective of the presence or absence of the gate bias voltage. PMID:24713634

  14. A 3-years full-scale mechanical ice deformation test from the artificial drainages of the Tête Rousse cavity

    NASA Astrophysics Data System (ADS)

    Gagliardini, Olivier; Krug, Jean; Gillet-Chaulet, Fabien; Durand, Gaël; Gilbert, Adrien; Thibert, Emmanuel; Vincent, Christian; Weiss, Jérôme

    2013-04-01

    History of the city of Saint Gervais Mont Blanc, in the french Alps, is deeply marked by the 1892 disaster which killed 175 persons, after the unexpected release of 100000 m3 of water contained in a hidden cavity inside the Tête-Rousse glacier. During summer 2010, a pressurised water-filled cavity of at least 50000 m3 was again discovered within the glacier. To avoid a repetition of the 1892 disaster, an unprecedented initiative has been risen up to drain the water cavity under this high altitude glacier. This procedure was further repeated in Autumns 2011 and 2012 since the cavity was permanently refiled in-between two drainages. However, as the cavity was decreasing in size due to the creep of ice when the water level was low, the total water volume drained out of the cavity was decreased each Autumn. At the same time, a dense network of stakes was deployed to survey the glacier surface displacements above the cavity during the pumping. Record of the water level evolution within the cavity together with the surface displacement measurements along an almost 3-years period constitute a very well documented full-scale experiment to characterise ice deformation. When the water level is low, the cavity is shrinking, whereas when the cavity is full of pressurised water, the cavity is growing. Because of the density ratio between ice and water, closing is approximately 9 time faster than opening. This dataset is completed by recently acquired surface and bedrock DEMs, as well as an image of the cavity geometry from sonar and radar measurements. This unique dataset was then used to constraint the finite-element ice flow model Elmer/Ice and perform transient simulations over the 3-years period. Both the evolution of the surface displacements and of the cavity volume are compared to measurements. We show the importance of accounting for ice damage to reproduce the observed surface displacements.

  15. A two-time-period comparison of the effects of ambient air pollution on outpatient visits for acute respiratory illnesses.

    PubMed

    Sinclair, Amber Hughes; Edgerton, Eric S; Wyzga, Ron; Tolsma, Dennis

    2010-02-01

    Concentrations of numerous ambient air pollutants have declined in recent years across the United States. Although it can be expected that reductions in air pollutants are associated with reductions in health effects, it is unclear whether this is actually the case. The purpose of this analysis was to compare the levels of and relationships between air pollutants and acute respiratory outpatient visits for two consecutive time periods totaling 53 mo. Air pollution data were collected at a centrally located monitor in Atlanta, GA, and include 24-hr averages of particulate matter (PM) less than 2.5 microm in aerodynamic diameter (PM2.5) and its components; coarse PM (PM10-2.5); PM less than 10 microm in aerodynamic diameter (PM10); oxygenated volatile organic compounds (OVOCs); 8-hr maximum ozone (O3); and 1-hr maximum nitrogen dioxide (NO2), carbon monoxide (CO), and sulfur dioxide (SO2). In addition, several metals and fractions of elemental carbon (EC) and organic carbon (OC) were investigated. Daily outpatient visit data were obtained from the electronic data warehouse of the Atlanta-based region of a nonprofit managed care organization. Poisson general linear modeling determined associations between daily levels of acute visits for four diagnosis groups (adult and child asthma, upper and lower respiratory infection) and air pollution measurements. Overall declining trends were observed in air pollutants and acute visits over the study period. Childhood asthma had the greatest number of significant associations with air pollutants, namely zinc and EC. The significant lag time between pollutant measurement and visit occurrence changed from 3-5 days in the first time period to 6-8 days in the later time period, but there was general consistency in several childhood asthma and pollutant associations over both time periods. The greatest evidence for a reduction in pollution being associated with an improvement in health response was for lower respiratory disease

  16. Time-varying autoregressive model for spectral analysis of microseismic experiments and long-period volcanic events

    NASA Astrophysics Data System (ADS)

    Tary, J. B.; Herrera, R. H.; van der Baan, M.

    2014-01-01

    Recent studies show that the frequency content of continuous passive recordings contains useful information for the study of hydraulic fracturing experiments as well as longstanding applications in volcano and global seismology. The short-time Fourier transform (STFT) is usually used to obtain the time-frequency representation of a seismic trace. Yet, this transform has two main disadvantages, namely its fixed time-frequency resolution and spectral leakage. Here, we describe two methods based on autoregressive (AR) models: the short-time autoregressive method (ST-AR) and the Kalman smoother (KS). These two methods allow for the AR coefficients to vary over time in order to follow time-varying frequency contents. The outcome of AR methods depends mainly on the number of AR coefficients. We use a robust approach to estimate the optimum order of the AR methods that best matches the spectral comparison between Fourier and AR spectra. Comparing the outcomes of the three methods on a synthetic signal, a long-period volcanic event, and microseismic data, we show that the STFT and both AR methods are able to track fast changes in frequency content. The STFT provides reasonable results even for noisy data using a simple and effective algorithm. The coefficients of the AR filter are defined at all time in the case of the KS. However, its better time resolution is slightly offset by a lower frequency resolution and its computational complexity. The ST-AR has a high spectral resolution and the lowest sensitivity to background noises, facilitating the identification of the various frequency components. The estimated AR coefficients can also be used to extract parts of the signal. The study of long-term phenomena, such as resonance frequencies, or transient events, such as long-period events, could help to gain further insight on reservoir deformation during hydraulic fracturing experiments as well as global or volcano seismological signals.

  17. System-specific periodicity in quantitative real-time polymerase chain reaction data questions threshold-based quantitation

    PubMed Central

    Spiess, Andrej-Nikolai; Rödiger, Stefan; Burdukiewicz, Michał; Volksdorf, Thomas; Tellinghuisen, Joel

    2016-01-01

    Real-time quantitative polymerase chain reaction (qPCR) data are found to display periodic patterns in the fluorescence intensity as a function of sample number for fixed cycle number. This behavior is seen for technical replicate datasets recorded on several different commercial instruments; it occurs in the baseline region and typically increases with increasing cycle number in the growth and plateau regions. Autocorrelation analysis reveals periodicities of 12 for 96-well systems and 24 for a 384-well system, indicating a correlation with block architecture. Passive dye experiments show that the effect may be from optical detector bias. Importantly, the signal periodicity manifests as periodicity in quantification cycle (Cq) values when these are estimated by the widely applied fixed threshold approach, but not when scale-insensitive markers like first- and second-derivative maxima are used. Accordingly, any scale variability in the growth curves will lead to bias in constant-threshold-based Cqs, making it mandatory that workers should either use scale-insensitive Cqs or normalize their growth curves to constant amplitude before applying the constant threshold method. PMID:27958340

  18. Prevalence of Mental Disorders and Suicidal Thoughts Among Community-Dwelling Elderly Adults 3 Years After the Niigata-Chuetsu Earthquake

    PubMed Central

    Suzuki, Yuriko; Tsutsumi, Atsuro; Fukasawa, Maiko; Honma, Hiroko; Someya, Toshiyuki; Kim, Yoshiharu

    2011-01-01

    Background Japan is located in an area prone to natural disasters, and major earthquakes have occurred recently in rural areas where the proportion of elderly adults is high. Although elderly persons are vulnerable members of communities at a time of disaster, the prevalence of mental disorders among this population has yet to be reported in Japan. This study aimed to determine the prevalence of mental disorders and suicidal thoughts among community-dwelling elderly persons 3 years after an earthquake and to identify risk factors associated with their quality of life (QOL). Methods Face-to-face interviews were conducted with 496 community-dwelling persons aged 65 years or older in areas of Japan where 2 major earthquakes had occurred during a 3-year period. The main outcome was diagnosis of a mental disorder or suicidality. Results During the 3-year period after the earthquake, 1.6% of men and 5.5% of women had received a diagnosis of major depression. There were no cases of posttraumatic stress disorder. Women were more likely than men to report suicidality (7.8% vs 3.8%, P = 0.075). Conclusions The prevalence of mental disorders was lower than that reported in previous studies. Despite the low prevalence of mental disorders, the percentage of community-dwelling elderly persons with subclinical mental health symptoms was high. The results indicate that appropriate public health and medical interventions are warranted after a natural disaster. PMID:21325733

  19. Onset time of binocular rivalry and duration of inter-dominance periods as psychophysical markers of ADHD.

    PubMed

    Aznar Casanova, J Antonio; Amador Campos, Juan Antonio; Moreno Sánchez, Manuel; Supér, Hans

    2013-01-01

    Attention deficit hyperactivity disorder (ADHD) is one of the main neurobiological disorders in young children. Despite its prevalence, current diagnosis is debated. In this study we tested whether measures of binocular rivalry (BR) can contribute to the diagnosis of ADHD. BR is a phenomenon that is produced when two different images are presented to the two eyes simultaneously. Under these conditions the image presented to one eye competes with that presented to the other eye in seeking to achieve perceptual dominance. This competition is resolved through the activation of a given percept coupled with the suppression of the percept that had predominated until that point. We assume that the difficulty with inhibiting responses of ADHD children also affects their ability to inhibit the dominant image in a BR context. We analyzed the time to rivalry onset and the inter-dominance periods as measures of the temporal cost of resolving how long it takes for the brain to select (or suppress) one percept over the other. Our results show that the time to onset of rivalry (the first dominance) was longer in the clinical groups (ADHD-C and ADHD-I) than in the control group. As regards the inter-dominance periods, these were longer in the ADHD-C group than among controls, with the shortest period corresponding to the ADHD-I group. This study shows that BR can be used as a tool to develop a behavioral indicator of ADHD.

  20. Altering Transplantation Time to Avoid Periods of High Temperature Can Efficiently Reduce Bacterial Wilt Disease Incidence with Tomato.

    PubMed

    Wei, Zhong; Huang, Jian-Feng; Hu, Jie; Gu, Yi-An; Yang, Chun-Lan; Mei, Xin-Lan; Shen, Qi-Rong; Xu, Yang-Chun; Friman, Ville-Petri

    2015-01-01

    Tomato bacterial wilt caused by Ralstonia solanacearum bacterium is a severe problem in Southern China, where relatively high environmental temperatures commonly prevails during the crop seasons. Previous research has indicated that bacterial wilt disease incidence generally increases during the warm months of summer leading to reduced tomato yield. Moreover, the efficacy of bio-organic fertilizers (BOFs)-organic compost fortified with pathogen-suppressive bacteria-is often lost during the periods of high environmental temperatures. Here we studied if the disease incidence could be reduced and the BOF performance enhanced by simply preponing and postponing the traditional seedling transplantation times to avoid tomato plant development during periods of high environmental temperature. To this end, a continuous, two-year field experiment was conducted to evaluate the performance of BOF in two traditional (late-spring [LS] and early-autumn [EA]) and two alternative (early-spring [ES] and late-autumn [LA]) crop seasons. We found that changing the transplantation times reduced the mean disease incidence from 33.9% (LS) and 54.7% (EA) to 11.1% (ES) and 7.1% (LA), respectively. Reduction in disease incidence correlated with the reduction in R. Solanacearum pathogen density in the tomato plant rhizosphere and stem base. Applying BOF during alternative transplantation treatments improved biocontrol efficiency from 43.4% (LS) and 3.1% (EA) to 67.4% (ES) and 64.8% (LA). On average, the mean maximum air temperatures were positively correlated with the disease incidence, and negatively correlated with the BOF biocontrol efficacy over the crop seasons. Crucially, even though preponing the transplantation time reduced the tomato yield in general, it was still economically more profitable compared to LS season due to reduced crop losses and relatively higher market prices. Preponing and postponing traditional tomato transplantation times to cooler periods could thus offer simple

  1. Altering Transplantation Time to Avoid Periods of High Temperature Can Efficiently Reduce Bacterial Wilt Disease Incidence with Tomato

    PubMed Central

    Wei, Zhong; Huang, Jian-Feng; Hu, Jie; Gu, Yi-An; Yang, Chun-Lan; Mei, Xin-Lan; Shen, Qi-Rong; Xu, Yang-Chun; Friman, Ville-Petri

    2015-01-01

    Tomato bacterial wilt caused by Ralstonia solanacearum bacterium is a severe problem in Southern China, where relatively high environmental temperatures commonly prevails during the crop seasons. Previous research has indicated that bacterial wilt disease incidence generally increases during the warm months of summer leading to reduced tomato yield. Moreover, the efficacy of bio-organic fertilizers (BOFs)–organic compost fortified with pathogen-suppressive bacteria—is often lost during the periods of high environmental temperatures. Here we studied if the disease incidence could be reduced and the BOF performance enhanced by simply preponing and postponing the traditional seedling transplantation times to avoid tomato plant development during periods of high environmental temperature. To this end, a continuous, two-year field experiment was conducted to evaluate the performance of BOF in two traditional (late-spring [LS] and early-autumn [EA]) and two alternative (early-spring [ES] and late-autumn [LA]) crop seasons. We found that changing the transplantation times reduced the mean disease incidence from 33.9% (LS) and 54.7% (EA) to 11.1% (ES) and 7.1% (LA), respectively. Reduction in disease incidence correlated with the reduction in R. Solanacearum pathogen density in the tomato plant rhizosphere and stem base. Applying BOF during alternative transplantation treatments improved biocontrol efficiency from 43.4% (LS) and 3.1% (EA) to 67.4% (ES) and 64.8% (LA). On average, the mean maximum air temperatures were positively correlated with the disease incidence, and negatively correlated with the BOF biocontrol efficacy over the crop seasons. Crucially, even though preponing the transplantation time reduced the tomato yield in general, it was still economically more profitable compared to LS season due to reduced crop losses and relatively higher market prices. Preponing and postponing traditional tomato transplantation times to cooler periods could thus offer

  2. Existence and global exponential stability of periodic solution of memristor-based BAM neural networks with time-varying delays.

    PubMed

    Li, Hongfei; Jiang, Haijun; Hu, Cheng

    2016-03-01

    In this paper, we investigate a class of memristor-based BAM neural networks with time-varying delays. Under the framework of Filippov solutions, boundedness and ultimate boundedness of solutions of memristor-based BAM neural networks are guaranteed by Chain rule and inequalities technique. Moreover, a new method involving Yoshizawa-like theorem is favorably employed to acquire the existence of periodic solution. By applying the theory of set-valued maps and functional differential inclusions, an available Lyapunov functional and some new testable algebraic criteria are derived for ensuring the uniqueness and global exponential stability of periodic solution of memristor-based BAM neural networks. The obtained results expand and complement some previous work on memristor-based BAM neural networks. Finally, a numerical example is provided to show the applicability and effectiveness of our theoretical results.

  3. Using time scales to characterize phytoplankton assemblages in a deep subalpine lake during the thermal stratification period: Lake Iseo, Italy

    NASA Astrophysics Data System (ADS)

    Marti, Clelia Luisa; Imberger, Jörg; Garibaldi, Letizia; Leoni, Barbara

    2016-03-01

    A combination of field observations and 3-D hydrodynamic simulations were used to identify the phytoplankton species and to estimate the various time scales of the dominant physical and biological processes in Lake Iseo, a deep subalpine lake located in northern Italy, during a stratified period (July 2010). By ordering the rate processes time scales, we derive a phytoplankton patch categorization and growth interpretation that provides a general framework for the spatial distribution of phytoplankton concentration in Lake Iseo and illuminates the characteristics of their ecological niches. The results show that the diurnal surface layer was well mixed, received strong diurnal radiation, had low phosphorus concentrations and the phytoplankton biomass was sustained by the green alga Sphaerocystis schroeterii. The vertical mixing time scales were much shorter than horizontal mixing time scales causing a depth-uniform chlorophyll a concentration. The horizontal patch scale was determined by horizontal dispersion balancing the phytoplankton growth time scale, dictating the success of the observed green algae. The strongly stratified nutrient-rich metalimnion had mild light conditions and Diatoma elongatum and Planktothrix rubescens made up the largest proportions of the total phytoplankton biomass at the intermediate and deeper metalimnetic layers. The vertical transport time scales were much shorter than horizontal transport and vertical dispersion leading to growth niche for the observed phytoplankton. The study showed that time-scale hierarchy mandates the essential phytoplankton attributes or traits for success in a particular section of the water column and/or water body.

  4. ISS ECLSS: 3 Years of Logistics for Maintenance

    NASA Technical Reports Server (NTRS)

    Shkedi, Brienne; Thompson, Dean

    2004-01-01

    The International Space Station (ISS) Environmental Control and Life Support System (ECLSS) is designed to be maintainable. During the 3 years since the ISS US Lab became operational, there have been numerous ECLSS Orbital Replacement Units (ORUs) launched and returned to Maintain the ECLSS operation in the US segments. The maintenance logistics have provided tools for maintenance, replaced limited life ORUs and failed ORUs, upgraded ECLSS hardware to improve reliability and placed critical spares onboard prior to need. In most cases, the removed ORUs have been returned for either failure analysis and repair or refurbishment. This paper describes the ECLSS manifesting history and maintenance events and quantifies the numbers of ECLSS items, weights, and volumes.

  5. Extrinsic Rewards Diminish Costly Sharing in 3-Year-Olds.

    PubMed

    Ulber, Julia; Hamann, Katharina; Tomasello, Michael

    2016-07-01

    Two studies investigated the influence of external rewards and social praise in young children's fairness-related behavior. The motivation of ninety-six 3-year-olds' to equalize unfair resource allocations was measured in three scenarios (collaboration, windfall, and dictator game) following three different treatments (material reward, verbal praise, and neutral response). In all scenarios, children's willingness to engage in costly sharing was negatively influenced when they had received a reward for equal sharing during treatment than when they had received praise or no reward. The negative effect of material rewards was not due to subjects responding in kind to their partner's termination of rewards. These results provide new evidence for the intrinsic motivation of prosociality-in this case, costly sharing behavior-in preschool children.

  6. Transient Supersaturation Supports Drug Absorption from Lipid-Based Formulations for Short Periods of Time, but Ongoing Solubilization Is Required for Longer Absorption Periods.

    PubMed

    Crum, Matthew F; Trevaskis, Natalie L; Pouton, Colin W; Porter, Christopher J H

    2017-02-06

    The current studies sought to explore the impact of drug supersaturation and precipitation during the dispersion and digestion of lipid-based formulations (LBFs), on in vivo absorption using a coupled in vitro digestion-in vivo perfusion absorption model. Fenofibrate absorption was evaluated from a number of LBFs with different solubilization and supersaturation capacities, and conditions at the absorptive membrane manipulated by changing perfusion conditions, intestine segment lengths, and by the conduct of experiments in the presence or absence of suspended/precipitated drug. LBF dispersion and digestion resulted in varying periods of supersaturation across the different formulations. Even fleeting (5-10 min) periods of supersaturation were able to drive flux across a perfused 10 cm intestinal segment for up to 60 min, although over longer infusion periods (60-80 min) flux dropped in the absence of ongoing drug solubilization and supersaturation. In contrast, the presence or absence of precipitated/suspended drug, had little impact on drug flux. When perfused intestinal segment lengths were extended, the role of initial supersaturation was attenuated and ongoing solubilization conditions became the primary driver of absorptive flux. The data suggest that for highly permeable drugs such as fenofibrate, a short period of supersaturation at the absorptive membrane may be sufficient to drive absorptive drug flux in spite of significant drug precipitation on formulation dispersion or digestion in vitro. In contrast, where longer periods of absorption are required, for example, at higher doses, the requirement for ongoing solubilization and supersaturation becomes more apparent.

  7. Osteocyte density in the peri-implant bone of implants retrieved after different time periods (4 weeks to 27 years).

    PubMed

    Piattelli, Adriano; Artese, Luciano; Penitente, Enrico; Iaculli, Flavia; Degidi, Marco; Mangano, Carlo; Shibli, Jamil Awad; Coelho, Paulo G; Perrotti, Vittoria; Iezzi, Giovanna

    2014-02-01

    Bone tissue is characterized by a constant turnover in response to mechanical stimuli, and osteocytes play an essential role in bone mechanical adaptation. However, little to no information has been published regarding osteocyte density as a function of implantation time in vivo. The aim of this retrospective histological study was to evaluate the osteocyte density of the peri-implant bone in implants retrieved because of different reasons in a time period from 4 weeks to 27 years. A total of 18 samples were included in the present study. Specimens were divided into 3 groups depending on the loading history of the implants: loading between 4 weeks and 7 months (group 1); loading between 1 and 5 years (group 2); loading between 14 and 27 years (group 3). All the samples were histologically evaluated and osteocyte density was obtained using the ratio of the number of osteocytes to the bone-area (mm(2) ). The osteocyte density values significantly increased in the Group 2 (1-5 years) compared with Group 1 (4 weeks-7 months), and significantly decreased in the Group 3 (14-27 years) compared to Group 2. No significant differences were detected between Group 1 and Group 3. The decrease in osteocyte density observed in samples that were in vivo for long periods of time under loading is possibly because of the fact that once the bone structure is well aligned and biomechanically competent, a lower number of osteocytes are necessary to keep the tissue homeostasis under loading.

  8. One period coupon bond valuation with revised first passage time approach and the application in Indonesian corporate bond

    NASA Astrophysics Data System (ADS)

    Maruddani, Di Asih I.; Rosadi, Dedi; Gunardic, Abdurakhman

    2015-02-01

    The value of a corporate bond is conventionally expressed in terms of zero coupon bond. In practice, the most common form of debt instrument is coupon bond and allows early default before maturity as safety covenant for the bondholder. This paper study valuation for one period coupon bond, a coupon bond that only give one time coupon at the bond period. It assumes that the model give bondholder the right to reorganize a firm if its value falls below a given barrier. Revised first passage time approach is applied for default time rule. As a result, formulas of equity, liability, and probability of default is derived for this specified model. Straightforward integration under risk neutral pricing is used for deriving those formulas. For the application, bond of Bank Rakyat Indonesia (BRI) as one of the largest bank in Indonesia is analyzed. R computing show that value of the equity is IDR 453.724.549.000.000, the liability is IDR 2.657.394.000.000, and the probability if default is 5.645305E-47 %.

  9. Women's Heart Advantage Program: the impact 3 years later.

    PubMed

    Gombeski, William R; Kramer, R Kyle; Freed, Lisa; Foody, JoAnne; Parkosewich, Janet; Wilson, Tammi; Wack, Jeffery T; D'Onofrio, Gail

    2005-01-01

    Yale-New Haven Hospital, in partnership with Voluntary Hospital Association (VHA Inc), launched the Women's Heart Advantage program in March 2001. Major program components implemented include (1) a comprehensive initial and ongoing internal communication program; (2) a health promotion initiative including a 24-hour, 7-days-a-week women's heart line staffed by nurses and an Internet health question-and-answer forum; (3) significant ongoing communication with nurses and physicians; (4) a community outreach effort to educate poor and minority women; and (5) an aggressive effort to secure financial partners to underwrite the cost of the program. Before launching the program, a telephone survey of 300 randomly selected New Haven County women ages 40 to 70 years was initiated in January 2001 and repeated in January 2002, 2003, and 2004. Findings include (1) the percentage of women who recognize heart disease as the number-one killer of women their age increased from 26% in 2001 to 59% in 2004, (2) the percentage of women who would call 9-1-1 or go directly to a hospital emergency department increased from 63% in 2002 to 83% in 2004, and (3) the percentage of women aware of recent Women's Heart Advantage program promotion grew from 33% in 2002 to 50% in 2004. Perhaps most importantly, the number of women with heart problems admitted through the hospital's emergency department increased from 1528 per year in 2001 to 1870 per year in 2004 (7.5% annual increase), whereas the number of men with heart problems admitted through the emergency department during the same time period has been relatively low (0.8% annual increase). By linking clinical, public health, and marketing expertise along with finding ways to partner with other organizations, the Women's Heart Advantage program has contributed to remarkable changes in women's awareness, knowledge, and behaviors, suggesting a model for approaching similar health-related problems.

  10. Bifurcation and temporal periodic patterns in a plant-pollinator model with diffusion and time delay effects.

    PubMed

    Huang, Jirong; Liu, Zhihua; Ruan, Shigui

    2017-03-01

    This paper deals with a plant-pollinator model with diffusion and time delay effects. By considering the distribution of eigenvalues of the corresponding linearized equation, we first study stability of the positive constant steady-state and existence of spatially homogeneous and spatially inhomogeneous periodic solutions are investigated. We then derive an explicit formula for determining the direction and stability of the Hopf bifurcation by applying the normal form theory and the centre manifold reduction for partial functional differential equations. Finally, we present an example and numerical simulations to illustrate the obtained theoretical results.

  11. Decomposing the effects of time on the social acceptability of biotechnology using age-period-cohort-country models.

    PubMed

    Rousselière, Damien; Rousselière, Samira

    2016-01-11

    The study of European attitudes toward biotechnologies underlines a situation that is relatively contrasting in Europe. However, as different effects of time can influence the social attitudes (a life-cycle effect, a generational effect, and an exogenous temporal effect potentially affecting the entire population), an appropriate methodology should be used. To this end, age-period-cohort-country models have thus been estimated based on Eurobarometer data from 1991 onward. Applied to different data subsets, these models give similar results underlining the importance of the life-cycle effects as well as the heterogeneity of the link between political affiliation and biotechnologies attitudes across the European countries.

  12. Timing and causes of North African wet phases during the last glacial period and implications for modern human migration

    NASA Astrophysics Data System (ADS)

    Hoffmann, Dirk L.; Rogerson, Mike; Spötl, Christoph; Luetscher, Marc; Vance, Derek; Osborne, Anne H.; Fello, Nuri M.; Moseley, Gina E.

    2016-11-01

    We present the first speleothem-derived central North Africa rainfall record for the last glacial period. The record reveals three main wet periods at 65-61 ka, 52.5-50.5 ka and 37.5-33 ka that lead obliquity maxima and precession minima. We find additional minor wet episodes that are synchronous with Greenland interstadials. Our results demonstrate that sub-tropical hydrology is forced by both orbital cyclicity and North Atlantic moisture sources. The record shows that after the end of a Saharan wet phase around 70 ka ago, North Africa continued to intermittently receive substantially more rainfall than today, resulting in favourable environmental conditions for modern human expansion. The encounter and subsequent mixture of Neanderthals and modern humans – which, on genetic evidence, is considered to have occurred between 60 and 50 ka – occurred synchronously with the wet phase between 52.5 and 50.5 ka. Based on genetic evidence the dispersal of modern humans into Eurasia started less than 55 ka ago. This may have been initiated by dry conditions that prevailed in North Africa after 50.5 ka. The timing of a migration reversal of modern humans from Eurasia into North Africa is suggested to be coincident with the wet period between 37.5 and 33 ka.

  13. Timing and causes of North African wet phases during the last glacial period and implications for modern human migration

    PubMed Central

    Hoffmann, Dirk L.; Rogerson, Mike; Spötl, Christoph; Luetscher, Marc; Vance, Derek; Osborne, Anne H.; Fello, Nuri M.; Moseley, Gina E.

    2016-01-01

    We present the first speleothem-derived central North Africa rainfall record for the last glacial period. The record reveals three main wet periods at 65-61 ka, 52.5-50.5 ka and 37.5-33 ka that lead obliquity maxima and precession minima. We find additional minor wet episodes that are synchronous with Greenland interstadials. Our results demonstrate that sub-tropical hydrology is forced by both orbital cyclicity and North Atlantic moisture sources. The record shows that after the end of a Saharan wet phase around 70 ka ago, North Africa continued to intermittently receive substantially more rainfall than today, resulting in favourable environmental conditions for modern human expansion. The encounter and subsequent mixture of Neanderthals and modern humans – which, on genetic evidence, is considered to have occurred between 60 and 50 ka – occurred synchronously with the wet phase between 52.5 and 50.5 ka. Based on genetic evidence the dispersal of modern humans into Eurasia started less than 55 ka ago. This may have been initiated by dry conditions that prevailed in North Africa after 50.5 ka. The timing of a migration reversal of modern humans from Eurasia into North Africa is suggested to be coincident with the wet period between 37.5 and 33 ka. PMID:27808237

  14. In-plane time-harmonic elastic wave motion and resonance phenomena in a layered phononic crystal with periodic cracks.

    PubMed

    Golub, Mikhail V; Zhang, Chuanzeng

    2015-01-01

    This paper presents an elastodynamic analysis of two-dimensional time-harmonic elastic wave propagation in periodically multilayered elastic composites, which are also frequently referred to as one-dimensional phononic crystals, with a periodic array of strip-like interior or interface cracks. The transfer matrix method and the boundary integral equation method in conjunction with the Bloch-Floquet theorem are applied to compute the elastic wave fields in the layered periodic composites. The effects of the crack size, spacing, and location, as well as the incidence angle and the type of incident elastic waves on the wave propagation characteristics in the composite structure are investigated in details. In particular, the band-gaps, the localization and the resonances of elastic waves are revealed by numerical examples. In order to understand better the wave propagation phenomena in layered phononic crystals with distributed cracks, the energy flow vector of Umov and the corresponding energy streamlines are visualized and analyzed. The numerical results demonstrate that large energy vortices obstruct elastic wave propagation in layered phononic crystals at resonance frequencies. They occur before the cracks reflecting most of the energy transmitted by the incoming wave and disappear when the problem parameters are shifted from the resonant ones.

  15. Final Report for 3-year grant no. DE-FG05-85ER40226. Investigations in Elementary Particle Theory.

    SciTech Connect

    Kephart, Thomas W.; Scherrer, Robert J.; Weiler, Thomas J.

    2014-11-23

    The research interests of our three Co-PI’s complement each other very well. Kephart works mainly on models of particle unification in four or higher dimensions, on aspects of gravity such as inflation, black-holes, and the very early Universe, and on applications of knot theory and topology to various physical systems (including gluon dynamics). Scherrer works mainly on aspects of the intermediate-aged Universe, including dark matter and dark energy, and particle physics in the early Universe. Weiler works mainly on neutrino physics, dark matter signatures, and extreme particle-astrophysics in the late Universe, including origins of the highest-energy cosmic-rays and gamma-rays, and the future potential of neutrino astrophysics. Kephart and Weiler have lately devoted some research attention to the LHC and its reach for probing physics beyond the Standard Model. During the 3-year funding period, our grant supported one postdoc (Chiu Man Ho) and partially supported two students, Peter Denton and Lingjun Fu. Chiu Man collaborated with all three of the Co-PI’s during the 3-year funding period and published 16 refereed papers. Chiu Man has gone on to a postdoc with Steve Hsu at Michigan State University. Denton and Fu will both receive their PhDs during the 2014-15 academic year. The total number of our papers published in refereed journals by the three co-PIs during the period of this grant (2011-present) is 54. The total number of talks given by the group members during this time period, including seminars, colloquia, and conference presentations, is 47. Some details of the accomplishments of our DOE funded researchers during the grant period include Weiler being named a Simons Fellow in 2013. He presented an invited TEDx talk in 2012. His paper on closed timelike curves (2013) garnered a great deal of national publicity. Scherrer’s paper on the “little rip” (2011) fostered a new area of cosmological research, and the name “little rip” has now entered

  16. Development of temporomandibular disorder symptoms: a 3-year cohort study of university students.

    PubMed

    Akhter, R; Morita, M; Esaki, M; Nakamura, K; Kanehira, T

    2011-06-01

    The aims of this study were to examine the incidence of temporomandibular disorders (TMDs) over a 3-year period and to evaluate the risk of self-reported TMDs among university students in Japan. The study population comprised 2374 university students examined at the start of their undergraduate course and 492 students re-examined after 3 years using questionnaires on symptoms of TMD and experiences of jaw injury, stress, orthodontic treatment and parafunctional habits. Cumulative incidence (%) and relative risks were calculated overall. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to determine the degree of risks of these variables for symptoms of TMDs using logistic regression. Results of logistic regression analysis showed that male subjects with experience of jaw injury had a 3·54 (CI=1·45-8·68, P<0·01)-fold higher risk of temporomandibular joint (TMJ) pain than that for those who did not. Female subjects who reported experiencing stress and bruxism had 10·56 (CI=1·28-87·54, P<0·05)- and 5·00 (CI=1·21-20·71, P<0·05)-fold higher risks of TMJ sound, respectively, than the risk for female subjects who had not experienced stress or bruxism. The results indicated that experiences of jaw injury, stress and bruxism were significantly associated with increased risks of development of TMJ disorders in a 3-year cohort.

  17. Radiological evaluation of the Cresco system in combination with Osseospeed implants: a preliminary 3-year report

    PubMed Central

    BALDINI, N.; DE SANCTIS, M.; CAGIDIACO, M.C.; BALLERI, P.; VIGNOLETTI, F.; GORACCI, C.; FERRARI, M.

    2014-01-01

    SUMMARY Aim. In this preliminary study, the 3-year radiological outcomes of Osseospeed implant-supported fixed complete or partial prostheses made with two different laboratory protocols were compared. Methods. A convenience sample of 34 patients, who were either partially or completely edentulous in either jaw, were randomly assigned to two groups, of 17 patients each, using either a traditional laboratory protocol (control group) or the Cresco one (test group). The study’s objective was an assessment of marginal bone loss around implants, measured on intraoral radiographs at 3-year follow-up. Results. None of the implants inserted was lost during the study and radiological measurements of marginal bone level changes revealed that the mean marginal bone loss was respectively 0,73±0,33mm for test group and 0,88±1,13mm for control group. The differences between test and control groups were not statistically significant. Conclusion. This preliminary study did not demonstrate statistically significant differences in marginal bone loss around implant-prostheses prepared with the two different laboratory protocols, over the 3-year observational period. PMID:25694796

  18. Pipeline for uncoilable or failed aneurysms: 3-year follow-up results.

    PubMed

    Becske, Tibor; Potts, Matthew B; Shapiro, Maksim; Kallmes, David F; Brinjikji, Waleed; Saatci, Isil; McDougall, Cameron G; Szikora, István; Lanzino, Giuseppe; Moran, Christopher J; Woo, Henry H; Lopes, Demetrius K; Berez, Aaron L; Cher, Daniel J; Siddiqui, Adnan H; Levy, Elad I; Albuquerque, Felipe C; Fiorella, David J; Berentei, Zsolt; Marosföi, Miklós; Cekirge, Saruhan H; Nelson, Peter K

    2016-10-14

    late-onset hemorrhagic or ischemic cerebrovascular events or neurological deaths were observed in the 6-month through 3-year posttreatment period. Among 103 surviving patients, 85 underwent functional outcome assessment in which modified Rankin Scale scores of 0-1 were demonstrated in 80 subjects. CONCLUSIONS Pipeline embolization is safe and effective in the treatment of complex large and giant aneurysms of the intracranial internal carotid artery. Unlike more traditional endovascular treatments, flow diversion results in progressive vascular remodeling that leads to complete aneurysm obliteration over longer-term follow-up without delayed aneurysm recanalization and/or growth. Clinical trial registration no.: NCT00777088 ( clinicaltrials.gov ).

  19. Asymmetric interference in concurrent time-to-contact estimation: Cousin or twin of the psychological refractory period effect?

    PubMed

    Baurès, Robin; DeLucia, Patricia R; Olson, Megan; Oberfeld, Daniel

    2017-02-01

    In a reaction time (RT) task requiring fast responses to two stimuli presented close in time, human observers show a delayed RT to the second stimulus. This phenomenon has been attributed to a psychological refractory period (PRP). A similar asymmetric interference is found when performing multiple concurrent visual time-to-contact (TTC) estimations for moving objects, despite important differences between the tasks. In the present study, we studied the properties of the asymmetric interference found in the TTC task and compared them to the classical PRP effect. In Experiment 1, we varied the time interval between the two objects' arrival times to determine the dependence of the PRP-like effect on the asynchrony between the two TTCs. In Experiment 2, we investigated whether the physical or the perceived arrival order determined the asymmetric interference. Our results confirmed the existence of asymmetric interference in the multiple TTC estimation task, but also indicated important differences from the traditional PRP effect observed in the RT paradigm. The origins of these differences are discussed, as well as the practical implications.

  20. Sensate Scaffolds Coupled to Telemetry Can Monitor In Vivo Loading From Within a Joint Over Extended Periods of Time

    PubMed Central

    Geffre, Chris P.; Bliss, Cody L.; Szivek, John A.; DeYoung, Donald W.; Ruth, John T.; Margolis, David S.

    2008-01-01

    Polymer scaffolds have been used as a tool to provide growth and integration of engineered tissue substrates to repair damaged tissues in many organ systems including articular cartilage. Previous work has shown that “sensate” scaffolds, with integrated strain gauges have the potential for use as both a delivery vehicle for engineered cartilage as well as a device that can measure real time, in vivo joint loading. The purpose of this study was to use an implanted subminiature telemetry system to collect in vivo joint loading measurements over an extended period following placement of a “sensate” scaffold. Measurements were collected from seven of nine sensors that were implanted into the stifles of three canines. The limb loading rates and load distribution through gait were dependent on stride time but did not vary with time post op. The peak loads were not dependent on stride time but significantly increased with time post op. This demonstrated that peak loading measured with “sensate” scaffolds can be used to monitor healing. The portability of the “sensate” scaffolds coupled to telemetry systems highlights the potential use of this system in a clinical research setting to gather important information to improve tissue engineering and rehabilitation regimens. PMID:17557310

  1. Integral representation of exact solutions for the correlation times of rotators in periodic potentials - derivation of asymptotic expansions

    NASA Astrophysics Data System (ADS)

    Coffey, W. T.; Crothers, D. S. F.; Waldron, J. T.

    1994-03-01

    The derivation of asymptotic expansions from the exact solution of the three term recurrence relations arising in the study of the Brownian movement in a periodic potential is discussed. The discussion is illustrated by showing how the exact formulae for the longitudinal and transverse correlation times of a single axis rotator with two equivalent sites, which have been previously given as a series of products of modified Bessel functions, may be rendered in integral form using Watson's integral formula for the product of two modified Bessel functions. The method of steepest descents is applied to these solutions in order to obtain rigourous asymptotic formulae for the correlation times in the high potential barrier limit. The analogous results for rotation in three dimensions in the Maier-Saupe potential are treated briefly.

  2. The nighttime F-region climatology during magnetically quiet periods seen from TIMED/GUVI and DMSP

    NASA Astrophysics Data System (ADS)

    Kil, H.; Paxton, L.; Zhang, Y.; Wolven, B.; Morrison, D.

    2004-12-01

    In this study, we investigate the drivers of the nighttime climatology in the low- and middle-latitude ionosphere during quiet periods using the TIMED/GUVI and DMSP data. The observation results show that the seasonal hemispheric asymmetry in plasma density is primary induced by the summer-to-winter wind circulations while the longitudinal variations of the F-region morphology is produced by the contribution of the zonal winds that depends on the magnetic declination. However, the F-region morphology observed at 625 km from TIMED/GUVI does not precisely conform the morphology observed at 840 km from DMSP. We will discuss the differential neutral wind effect on the F-region morphology depending on the magnetic declination, altitude, and the location of the geomagnetic equator relative to the geographic equator.

  3. Duty periods with early start times restrict the amount of sleep obtained by short-haul airline pilots.

    PubMed

    Roach, Gregory D; Sargent, Charli; Darwent, David; Dawson, Drew

    2012-03-01

    Most of the research related to human fatigue in the aviation industry has focussed on long-haul pilots, but short-haul pilots also experience elevated levels of fatigue. The aim of this study was to examine the impact of early start times on the amount of sleep obtained prior to duty and on fatigue levels at the start of duty. Seventy short-haul pilots collected data regarding their duty schedule and sleep/wake behaviour for at least two weeks. Data were collected using self-report duty/sleep diaries and wrist activity monitors. Mixed-effects regression analyses were used to examine the effects of duty start time (04:00-10:00 h) on (i) the total amount of sleep obtained in the 12h prior to the start of duty and (ii) self-rated fatigue level at the start of duty. Both analyses indicated significant main effects of duty start time. In particular, the amount of sleep obtained in the 12h prior to duty was lowest for duty periods that commenced between 04:00 and 05:00 h (i.e. 5.4h), and greatest for duty periods that commenced between 09:00 and 10:00 h (i.e. 6.6h). These data indicate that approximately 15 min of sleep is lost for every hour that the start of duty is advanced prior to 09:00 h. In addition, self-rated fatigue at the start of duty was highest for duty periods that commenced between 04:00 and 05:00 h, and lowest for duty periods that commenced between 09:00 and 10:00 h. Airlines should implement a fatigue risk management system (FRMS) for short-haul pilots required to work early-morning shifts. One component of the FRMS should be focussed on the production of 'fatigue-friendly' rosters. A second component of the FRMS should be focussed on training pilots to optimise sleep opportunities, to identify circumstances where the likelihood of fatigue is elevated, and to manage the risks associated with fatigue-related impairment.

  4. Walls of Time: The "Walk through Time" Was Inspired by How Artists of Various Time Periods and Cultures Have Decorated Walls

    ERIC Educational Resources Information Center

    Komrska, Shelley; Rupe, Melissa

    2005-01-01

    Last year, a school embarked on a school-wide project that would take all of their students, kindergarten through-sixth grade, through a tangible art timeline. The result was a passageway--over seventy-five feet in length--that revealed the history of art, from cave painting to modern-day graffiti art. The "walk through time" was inspired by how…

  5. Age, time period, and birth cohort differences in self-esteem: Reexamining a cohort-sequential longitudinal study.

    PubMed

    Twenge, Jean M; Carter, Nathan T; Campbell, W Keith

    2016-12-08

    Orth, Trzesniewski, and Robins (2010) concluded that the nationally representative Americans' Changing Lives (ACL) cohort-sequential study demonstrated moderate to large age differences in self-esteem, and no birth cohort (generational) differences in the age trajectory. In a reanalysis of these data using 2 different statistical techniques, we find significant increases in self-esteem that could be attributed to birth cohort or time period. First, hierarchical linear modeling analyses with birth cohort as a continuous variable (vs. the multiple group formulation used by Orth et al.) find that birth cohort has a measurable influence on self-esteem through its interaction with age. Participants born in later years (e.g., 1960) were higher in self-esteem and were more likely to increase in self-esteem as they aged than participants born in earlier years (e.g., 1920). However, the estimated age trajectory up to age 60 is similar in Orth et al.'s results and in the results from our analyses including cohort. Second, comparing ACL respondents of the same age in 1986 versus 2002 (a time-lag design) yields significant birth cohort differences in self-esteem, with 2002 participants of the same age higher in self-esteem than those in 1986. Combined with some previous studies finding significant increases in self-esteem and positive self-views over time, these results suggest that cultural change in the form of cohort and time period cannot be ignored as influences in cross-sectional and longitudinal studies. (PsycINFO Database Record

  6. Acceleration of Ab Initio QM/MM Calculations under Periodic Boundary Conditions by Multiscale and Multiple Time Step Approaches.

    PubMed

    Nam, Kwangho

    2014-10-14

    Development of multiscale ab initio quantum mechanical and molecular mechanical (AI-QM/MM) method for periodic boundary molecular dynamics (MD) simulations and their acceleration by multiple time step approach are described. The developed method achieves accuracy and efficiency by integrating the AI-QM/MM level of theory and the previously developed semiempirical (SE) QM/MM-Ewald sum method [J. Chem. Theory Comput. 2005, 1, 2] extended to the smooth particle-mesh Ewald (PME) summation method. In the developed methods, the total energy of the simulated system is evaluated at the SE-QM/MM-PME level of theory to include long-range QM/MM electrostatic interactions, which is then corrected on the fly using the AI-QM/MM level of theory within the real space cutoff. The resulting energy expression enables decomposition of total forces applied to each atom into forces determined at the low-level SE-QM/MM method and correction forces at the AI-QM/MM level, to integrate the system using the reversible reference system propagator algorithm. The resulting method achieves a substantial speed-up of the entire calculation by minimizing the number of time-consuming energy and gradient evaluations at the AI-QM/MM level. Test calculations show that the developed multiple time step AI-QM/MM method yields MD trajectories and potential of mean force profiles comparable to single time step QM/MM results. The developed method, together with message passing interface (MPI) parallelization, accelerates the present AI-QM/MM MD simulations about 30-fold relative to the speed of single-core AI-QM/MM simulations for the molecular systems tested in the present work, making the method less than one order slower than the SE-QM/MM methods under periodic boundary conditions.

  7. Solubility of Two Root-End Filling Materials over Different Time Periods in Synthetic Tissue Fluid: a Comparative Study

    PubMed Central

    Shojaee, Nooshin Sadat; Sahebi, Safoora; Karami, Elahe; Sobhnamayan, Fereshte

    2015-01-01

    Statement of the Problem Insolubility is an important criterion for an ideal root-end filling material to both prevent any microleakage between the root canal and the periradicular space and provide sealing ability. Purpose Many recent studies have shown that mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) have acceptable sealing ability. The purpose of this in vitro study was to evaluate the solubility of these root-end filling materials. Materials and Method Forty stainless steel ring moulds with an internal diameter of 10±1 mm and a height of 2±0.1 mm were selected. Samples of MTA and CEM were mixed according to the manufacturer’s instructions and inserted into the moulds. The specimens were divided into 4 experimental groups and kept in synthetic tissue fluid (STF) for 2 different time periods (7 and 28 days). The control group contained 8 empty rings. The moulds’ weights were recorded before and after immersion in STF. The changes in the weight of the samples were measured and compared using a two- way ANOVA test at a significance level of 5%. Specimens were evaluated with scanning electron microscopy (SEM) at a magnification of 500×. Results There was no significant difference in weight changes between MTA and CEM samples (p> 0.05). Conclusion MTA and CEM have similar solubility in STF in different time periods. PMID:26331148

  8. Spontaneous analog number representations in 3-year-old children.

    PubMed

    Cantlon, Jessica F; Safford, Kelley E; Brannon, Elizabeth M

    2010-03-01

    When enumerating small sets of elements nonverbally, human infants often show a set-size limitation whereby they are unable to represent sets larger than three elements. This finding has been interpreted as evidence that infants spontaneously represent small numbers with an object-file system instead of an analog magnitude system (Feigenson, Dehaene & Spelke, 2004). In contrast, non-human animals and adult humans have been shown to rely on analog magnitudes for representing both small and large numbers (Brannon & Terrace, 1998; Cantlon & Brannon, 2007; Cordes, Gelman, Gallistel & Whalen, 2001). Here we demonstrate that, like adults and non-human animals, children as young as 3 years of age spontaneously employ analog magnitude representations to enumerate both small and large sets. Moreover, we show that children spontaneously attend to numerical value in lieu of cumulative surface area. These findings provide evidence of young children's greater sensitivity to number relative to other quantities and demonstrate continuity in the process they spontaneously recruit to judge small and large values.

  9. A 3-year follow-up of hypertension in Delhi.

    PubMed Central

    Gopinath, N.; Chadha, S. L.; Shekhawat, S.; Tandon, R.

    1994-01-01

    A follow-up study of hypertension was carried out among adults in Delhi 3 years after an initial community-based epidemiological survey of the same population. The treatment and the severity status of 1115 out of 1749 individuals with hypertension detected in the initial survey were compared with those observed in the follow-up. The proportion of treated cases with controlled blood pressure rose from 10.8% to 60.8%. Among the cohort of 3611 subjects aged 25-64 years who were normotensive in the initial survey, 132 new cases of hypertension, were detected. The annual incidence of hypertension was the same in men and women (12.2 per 1000). Diabetes and regular alcohol consumption were significant risk factors for hypertension, being present in 13 and 7 cases, respectively. Electrocardiograms (ECGs) were recorded for 871 of the 1115 cases of hypertension. Abnormal ECGs were exhibited by 307 cases (35.2%), of which 24 (2.7%) had had myocardial infarction, 133 (15.3%) had ischaemic ST-T changes, 54 (6.2%) had left ventricular hypertrophy, and 96 (11.0%) had conduction defects and arrhythmias. PMID:7955019

  10. Time trend and age-period-cohort effect on kidney cancer mortality in Europe, 1981–2000

    PubMed Central

    Pérez-Farinós, Napoleón; López-Abente, Gonzalo; Pastor-Barriuso, Roberto

    2006-01-01

    Background The incorporation of diagnostic and therapeutic improvements, as well as the different smoking patterns, may have had an influence on the observed variability in renal cancer mortality across Europe. This study examined time trends in kidney cancer mortality in fourteen European countries during the last two decades of the 20th century. Methods Kidney cancer deaths and population estimates for each country during the period 1981–2000 were drawn from the World Health Organization Mortality Database. Age- and period-adjusted mortality rates, as well as annual percentage changes in age-adjusted mortality rates, were calculated for each country and geographical region. Log-linear Poisson models were also fitted to study the effect of age, death period, and birth cohort on kidney cancer mortality rates within each country. Results For men, the overall standardized kidney cancer mortality rates in the eastern, western, and northern European countries were 20, 25, and 53% higher than those for the southern European countries, respectively. However, age-adjusted mortality rates showed a significant annual decrease of -0.7% in the north of Europe, a moderate rise of 0.7% in the west, and substantial increases of 1.4% in the south and 2.0% in the east. This trend was similar among women, but with lower mortality rates. Age-period-cohort models showed three different birth-cohort patterns for both men and women: a decrease in mortality trend for those generations born after 1920 in the Nordic countries, a similar but lagged decline for cohorts born after 1930 in western and southern European countries, and a continuous increase throughout all birth cohorts in eastern Europe. Similar but more heterogeneous regional patterns were observed for period effects. Conclusion Kidney cancer mortality trends in Europe showed a clear north-south pattern, with high rates on a downward trend in the north, intermediate rates on a more marked rising trend in the east than in the

  11. Postoperative Mortality after Hip Fracture Surgery: A 3 Years Follow Up

    PubMed Central

    Un, Canan; Sacan, Ozlem; Gamli, Mehmet; Baskan, Semih; Baydar, Mustafa

    2016-01-01

    Background and Aims To determine mortality rates and predisposing factors in patients operated for a hip fracture in a 3-year follow-up period. Methods The study included patients who underwent primary surgery for a hip fracture.The inclusion criteria were traumatic, non-traumatic, osteoporotic and pathological hip fractures requiring surgery in all age groups and both genders. Patients with periprosthetic fractures or previous contralateral hip fracture surgery and patients who could not be contacted by telephone were excluded. At 36 months after surgery, evaluation was made using a structured telephone interview and a detailed examination of the hospital medical records, especially the documents written during anesthesia by the anesthesiologists and the documents written at the time of follow-up visits by the orthopaedic surgeons. A total of 124 cases were analyzed and 4 patients were excluded due to exclusion criteria. The collected data included demographics, type of fracture, co-morbidities, American Society of Anesthesiologists (ASA) scores, anesthesia techniques, operation type (intramedullary nailing or arthroplasty; cemented-noncemented), peroperative complications, refracture during the follow-up period, survival period and mortality causes. Results The total 120 patients evaluated comprised 74 females(61.7%) and 46 males(38.3%) with a mean age of 76.9±12.8 years (range 23–95 years). The ASA scores were ASA I (0.8%), ASA II (21.7%), ASA III (53.3%) and ASA IV (24.2%). Mortality was seen in 44 patients (36.7%) and 76 patients (63.3%) survived during the 36-month follow-up period. Of the surviving patients, 59.1% were female and 40.9% were male.The survival period ranged between 1–1190 days. The cumulative mortality rate in the first, second and third years were 29.17%, 33.33% and 36.67% respectively. The factors associated with mortality were determined as increasing age, high ASA score, coronary artery disease, congestive heart failure, Alzheimer

  12. Qualitative Feasibility of Using Three Accelerometers With 2-3-Year-Old Children and Both Parents

    ERIC Educational Resources Information Center

    Costa, Silvia; Barber, Sally E.; Griffiths, Paula L.; Cameron, Noël; Clemes, Stacy A.

    2013-01-01

    Purpose: This study assessed mothers' opinions about the feasibility and acceptability of using the ActiGraph GT3X+, Actiheart, and activPAL3 with their 2- to 3-year-old children, as well as with themselves and their husbands/partners, for an 8-day period. Method: Six focus groups were run with Pakistani and White British mothers ("n" =…

  13. Intergenerational Transmission of Warm-Sensitive-Stimulating Parenting: A Prospective Study of Mothers and Fathers of 3-Year-Olds

    ERIC Educational Resources Information Center

    Belsky, Jay; Jaffee, Sara R.; Sligo, Judith; Woodward, Lianne; Silva, Phil A.

    2005-01-01

    More than 200 New Zealand men and women studied repeatedly since age 3 were videotaped interacting with their own 3-year-old children to determine (a) whether childrearing and family climate experienced in 3 distinct developmental periods while growing up (i.e., early childhood, middle childhood, early adolescence) predicted parenting and (b)…

  14. Probabilistic assessment of exposure to cosmetic products by French children aged 0-3 years.

    PubMed

    Ficheux, A S; Dornic, N; Bernard, A; Chevillotte, G; Roudot, A C

    2016-08-01

    Very few exposure data are available for children in Europe and worldwide. The aim of this study was to assess the exposure to cosmetic products used on children aged 0-3 years using recent consumption data generated for the French population. Exposure was assessed using a probabilistic method for 24 products including cleanser, skin care, fragrance, solar and bottom products. The exposure data obtained in this study for children aged 0-3 years were higher than the values fixed by the SCCS for all common products: liquid shampoo, face moisturizer cream, toothpaste, shower gel and body moisturizer cream. Exposure was assessed for the first time for many products such as sunscreens, Eau de toilette and massage products. These new French exposure values will be useful for safety assessors and for safety agencies.

  15. Pharyngoesophageal perforation 3 years after anterior cervical spine surgery: a rare case report and literature review.

    PubMed

    Yin, Dan-Hui; Yang, Xin-Ming; Huang, Qi; Yang, Mi; Tang, Qin-Lai; Wang, Shu-Hui; Wang, Shuang; Liu, Jia-Jia; Yang, Tao; Li, Shi-Sheng

    2015-08-01

    Pharyngoesophageal perforation after anterior cervical spine surgery is rare and the delayed cases were more rarely reported but potentially life-threatening. We report a case of pharyngoesophageal perforation 3 years after anterior cervical spine surgery. The patient presented with dysphagia, fever, left cervical mass and developing dyspnea 3 years after cervical spine surgery for trauma. After careful examinations, he underwent an emergency tracheostomy, neck exploration, hardware removal, abscess drainage and infected tissue debridement. 14 days after surgery, CT of the neck with oral contrast demonstrated no contrast extravasation from the esophagus. Upon review of literature, only 14 cases of pharyngoesophageal perforation more than 1 year after anterior cervical spine surgery were found. We discussed possible etiology, diagnosis and management and concluded that in cases of dysphagia, dyspnea, cervical pain, swelling and edema of the cervical area even long time after anterior cervical spine surgery, potential pharyngoesophageal damage should be considered.

  16. Reflection and transmission of a wave incident on a slab with a time-periodic dielectric function {epsilon}(t)

    SciTech Connect

    Zurita-Sanchez, Jorge R.; Halevi, P.; Cervantes-Gonzalez, Juan C.

    2009-05-15

    We present a theoretical description of the response of a dynamic slab, with time-periodic dielectric function {epsilon}(t), to a normally incident monochromatic plane wave of frequency {omega}{sub o}. As a consequence of the interaction of this incoming wave with the dynamic slab, the reflected and transmitted waves contain harmonics of the modulating frequency {omega}, namely, the slab itself becomes a polychromatic source of frequencies {omega}{sub o}-n{omega}(n=0,{+-}1,{+-}2,...). We establish a general formalism to quantify the reflected and transmitted fields for any periodic variation in the dielectric function. To achieve this, a description of wave propagation in a dynamic bulk is needed. A theoretical framework to treat such propagation, based on the concept of a temporal photonic crystal, is developed. As a consequence of the Bloch-Floquet theorem, the dispersion relation is a band structure that is periodic with frequency and exhibits forbidden wave vector gaps. The Poynting vectors of the transmitted and reflected fields are analyzed in detail. Our theory is applied to the case in which the dielectric function is modulated sinusoidally. We calculate numerically the magnitudes and phases of the reflection and transmission coefficients for several harmonics {omega}{sub o}-n{omega} and slab thicknesses. Three modulation regimes are considered: weak, moderate, and strong. The response in the weak regime is similar to that of a Fabry-Perot etalon--the strengths of the harmonics are weak. For the strong-modulation regime, the strengths of reflection and transmission coefficients of the harmonics become large; they can even exceed one due to the openness of the system in which an external modulating agent can provide part of the invested energy. Dynamic variation in the dielectric properties of materials can give rise to new effects in wave propagation and to novel optical applications and is readily attainable with present-day technology.

  17. Global paths of time-periodic solutions of the Benjamin-Ono equation connecting arbitrary traveling waves

    SciTech Connect

    Ambrose, David M.; Wilkening, Jon

    2008-12-11

    We classify all bifurcations from traveling waves to non-trivial time-periodic solutions of the Benjamin-Ono equation that are predicted by linearization. We use a spectrally accurate numerical continuation method to study several paths of non-trivial solutions beyond the realm of linear theory. These paths are found to either re-connect with a different traveling wave or to blow up. In the latter case, as the bifurcation parameter approaches a critical value, the amplitude of the initial condition grows without bound and the period approaches zero. We propose a conjecture that gives the mapping from one bifurcation to its counterpart on the other side of the path of non-trivial solutions. By experimentation with data fitting, we identify the form of the exact solutions on the path connecting two traveling waves, which represents the Fourier coefficients of the solution as power sums of a finite number of particle positions whose elementary symmetric functions execute simple orbits in the complex plane (circles or epicycles). We then solve a system of algebraic equations to express the unknown constants in the new representation in terms of the mean, a spatial phase, a temporal phase, four integers (enumerating the bifurcation at each end of the path) and one additional bifurcation parameter. We also find examples of interior bifurcations from these paths of already non-trivial solutions, but we do not attempt to analyze their algebraic structure.

  18. Global Characteristics of the Correlation and Time Lag Between Solar and Ionospheric Parameters in the 27-day Period

    NASA Technical Reports Server (NTRS)

    Lee, Choon-Ki; Han, Shin-Chan; Dieter,Bilitza; Ki-Weon,Seo

    2012-01-01

    The 27-day variations of topside ionosphere are investigated using the in-situ electron density measurements from the CHAMP planar Langmuir probe and GRACE K-band ranging system. As the two satellite systems orbit at the altitudes of approx. 370 km and approx. 480 km, respectively, the satellite data sets are greatly valuable for examining the electron density variations in the vicinity of F2-peak. In a 27-day period, the electron density measurements from the satellites are in good agreements with the solar flux, except during the solar minimum period. The time delays are mostly 1-2 day and represent the hemispherical asymmetry. The globally-estimated spatial patterns of the correlation between solar flux and in-situ satellite measurements show poor correlations in the (magnetic) equatorial region, which are not found from the ground measurements of vertically-integrated electron content. We suggest that the most plausible cause for the poor correlation is the vertical movement of ionization due to atmospheric dynamic processes that is not controlled by the solar extreme ultraviolet radiation.

  19. Time, frequency and information domain analysis of heart period and QT variability in asymptomatic long QT syndrome type 2 patients.

    PubMed

    Bari, Vlasta; Girardengo, Giulia; Marchi, Andrea; De Maria, Beatrice; Brink, Paul A; Crotti, Lia; Schwartz, Peter J; Porta, Alberto

    2015-01-01

    This study was designed to characterize in time, frequency and information domains heart period (HP) and QT interval variabilities in asymptomatic (ASYMP) long QT syndrome type 2 (LQT2) subjects. HP, approximated as the temporal distance between two consecutive R-wave peaks, and QT, approximated as the temporal distance between the R-wave peak and the T-wave offset, were automatically derived from 24h Holter recordings in 10 ASYMP LQT2 patients and 13 healthy non mutation carriers (NMC) subjects. All analyses were carried out during DAY (from 2 to 6 PM) and NIGHT (from 12 to 4 AM). Mean, variance, spectral power and complexity indices at short, medium and long time scales were assessed over HP and QT beat-to-beat series. Circadian rhythmicity was evident in both NMC and ASYMP LQT2 but ASYMP LQT2 subjects were characterized by higher HP, QT interval and HP variability during both DAY and NIGHT. In addition, multiscale complexity analysis was able to differentiate the groups by showing a higher HP complexity and a lower QT complexity at long time scales in ASYMP LQT2 during DAY. ASYMP LQT2 exhibited a different autonomic control compared to NMC and such a differentiation could be protective and assure them a lower risk profile.

  20. CT image quality over time: comparison of image quality for six different CT scanners over a six-year period.

    PubMed

    Roa, Ana Maria A; Andersen, Hilde K; Martinsen, Anne Catrine T

    2015-03-08

    UNSCEAR concluded that increased use of CT scanning caused dramatic changes in population dose. Therefore, international radiation protection authorities demand: 1) periodical quality assurance tests with respect to image quality and radiation dose, and 2) optimization of all examination protocols with respect to image quality and radiation dose. This study aimed to evaluate and analyze multiple image quality parameters and variability measured throughout time for six different CT scanners from four different vendors, in order to evaluate the current methodology for QA controls of CT systems. The results from this study indicate that there is minor drifting in the image noise and uniformity and in the spatial resolution over time for CT scanners, independent of vendors. The HU for different object densities vary between different CT scanner models from different vendors, and over time for one specific CT scanner. Future tests of interphantom and intraphantom variations, along with inclusion of more CT scanners, are necessary to establish robust baselines and recommendations of methodology for QA controls of CT systems, independent of model and vendor.

  1. TIME DELAYS IN QUASI-PERIODIC PULSATIONS OBSERVED DURING THE X2.2 SOLAR FLARE ON 2011 FEBRUARY 15

    SciTech Connect

    Dolla, L.; Marque, C.; Seaton, D. B.; Dominique, M.; Berghmans, D.; Cabanas, C.; De Groof, A.; Verdini, A.; West, M. J.; Zhukov, A. N.; Van Doorsselaere, T.; Schmutz, W.; Zender, J.

    2012-04-10

    We report observations of quasi-periodic pulsations (QPPs) during the X2.2 flare of 2011 February 15, observed simultaneously in several wavebands. We focus on fluctuations on timescale 1-30 s and find different time lags between different wavebands. During the impulsive phase, the Reuven Ramaty High Energy Solar Spectroscopic Imager channels in the range 25-100 keV lead all the other channels. They are followed by the Nobeyama RadioPolarimeters at 9 and 17 GHz and the extreme-ultraviolet (EUV) channels of the Euv SpectroPhotometer (ESP) on board the Solar Dynamic Observatory. The zirconium and aluminum filter channels of the Large Yield Radiometer on board the Project for On-Board Autonomy satellite and the soft X-ray (SXR) channel of ESP follow. The largest lags occur in observations from the Geostationary Operational Environmental Satellite, where the channel at 1-8 A leads the 0.5-4 A channel by several seconds. The time lags between the first and last channels is up to Almost-Equal-To 9 s. We identified at least two distinct time intervals during the flare impulsive phase, during which the QPPs were associated with two different sources in the Nobeyama RadioHeliograph at 17 GHz. The radio as well as the hard X-ray channels showed different lags during these two intervals. To our knowledge, this is the first time that time lags are reported between EUV and SXR fluctuations on these timescales. We discuss possible emission mechanisms and interpretations, including flare electron trapping.

  2. 5 CFR 551.211 - Effect of performing different work or duties for a temporary period of time on FLSA exemption...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... temporary period of time on FLSA exemption status. (a) Applicability. Performing different work or duties... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Effect of performing different work or duties for a temporary period of time on FLSA exemption status. 551.211 Section 551.211...

  3. 5 CFR 551.211 - Effect of performing different work or duties for a temporary period of time on FLSA exemption...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... temporary period of time on FLSA exemption status. (a) Applicability. Performing different work or duties... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Effect of performing different work or duties for a temporary period of time on FLSA exemption status. 551.211 Section 551.211...

  4. 5 CFR 551.211 - Effect of performing different work or duties for a temporary period of time on FLSA exemption...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... temporary period of time on FLSA exemption status. (a) Applicability. Performing different work or duties... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Effect of performing different work or duties for a temporary period of time on FLSA exemption status. 551.211 Section 551.211...

  5. 5 CFR 551.211 - Effect of performing different work or duties for a temporary period of time on FLSA exemption...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... temporary period of time on FLSA exemption status. (a) Applicability. Performing different work or duties... 5 Administrative Personnel 1 2012-01-01 2012-01-01 false Effect of performing different work or duties for a temporary period of time on FLSA exemption status. 551.211 Section 551.211...

  6. 5 CFR 551.211 - Effect of performing different work or duties for a temporary period of time on FLSA exemption...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... temporary period of time on FLSA exemption status. (a) Applicability. Performing different work or duties... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Effect of performing different work or duties for a temporary period of time on FLSA exemption status. 551.211 Section 551.211...

  7. Backstepping control for periodically time-varying systems using high-order neural network and Fourier series expansion.

    PubMed

    Chen, Weisheng; Li, Wei; Miao, Qiguang

    2010-07-01

    An adaptive backstepping tracking scheme is developed for a class of strict-feedback systems with unknown periodically time-varying parameters and unknown control gain functions. High-order neural network (HONN) and Fourier series expansion (FSE) are combined into a new function approximator to model each uncertain term in the system. The dynamic surface control (DSC) approach is used to solve the problem of 'explosion of complexity' in the backstepping design procedure. Nussbaum gain function (NGF) is employed to deal with the unknown control gain functions. The uniform boundedness of all closed-loop signals is guaranteed. The tracking error is proved to converge to a small residual set around the origin. Two simulation examples are provided to demonstrate the effectiveness of the control scheme designed in this paper.

  8. Baldrige-based quality awards: Veterans Health Administration's 3-year experience.

    PubMed

    Shirks, Allan; Weeks, William B; Stein, Annie

    2002-01-01

    This article describes the Veterans Health Administration's (VHA's) 3-year experience with an internal, Baldrige-based quality award. The authors examined scores for Veterans Integrated Service Networks (VISNs), which received site visits, variation in year-to-year survey outcomes for repeat applicants, and variation in survey team reports for a VISN with multiple surveys. Individual VISNs that applied in multiple years had mixed results. Variation in feedback reports was not significant. Although some VISNs increased their scores over time, there was not measurable, systemwide improvement. Three years may be too short a time to significantly affect Baldrige scores in an organization as large as VHA.

  9. Transport of marked pebbles in short periods of time on a coarse clastic beach (Marina di Pisa, Italy)

    NASA Astrophysics Data System (ADS)

    Bertoni, D.; Ciavola, P.; Grottoli, E.; Sarti, G.

    2012-04-01

    Transport of coarse sediments on coarse clastic beaches still presents aspects that are not fully understood. For instance, there is a generally perceived notion that during fair-weather periods coarse grains hardly move, if not at all. The aim of this experiment is to prove that sediments such as pebbles are subject to significant shift in very short lapses of time and under low energy waves. An artificial coarse clastic beach at Marina di Pisa (Tuscany, Italy) was chosen as study site: Barbarossa beach is 110 m long and is bounded by two groynes. The mean grain size is about 40-to-50 mm. About 80 pebbles were marked by means of the RFID technology, which enables to univocally identify the tracers. The marked pebbles were released along cross-shore transects (one pebble each on the fair-weather berm, on the beachface and on the step crest) on the morning of September 15th, and two recovery campaigns were carried out after 6 and 24 hours from the injection. No particular wave activity was recorded during the time frame of the experiment. After the first recovery campaign, which was performed 6 hours later than the injection, about 94% of the pebbles were detected. After the second recovery campaign, 24 hours later, the recovery rate decreased to 89%. Considering that the technique provides for detection of tracers within 50 cm, the resulting loss of pebbles after so brief spans of time is remarkable. The lack of detection of few tracers implies that the transport rate that they experienced is not negligible. The highest rate of losses was recorded on the beachface, the zone that is subjected the most to waves even under calm conditions. Pebble movement is also confirmed by the fact that tracers detected after the first recovery campaign were not detected once again after the second recovery campaign, and vice versa. The results of the experiment are useful to better define the transport of coarse sediments, verifying that pebbles have to be expected be moving even

  10. On quality control procedures for solar radiation and meteorological measures, from subhourly to montly average time periods

    NASA Astrophysics Data System (ADS)

    Espinar, B.; Blanc, P.; Wald, L.; Hoyer-Klick, C.; Schroedter-Homscheidt, M.; Wanderer, T.

    2012-04-01

    Meteorological data measured by ground stations are often a key element in the development and validation of methods exploiting satellite images. These data are considered as a reference against which satellite-derived estimates are compared. Long-term radiation and meteorological measurements are available from a large number of measuring stations. However, close examination of the data often reveals a lack of quality, often for extended periods of time. This lack of quality has been the reason, in many cases, of the rejection of large amount of available data. The quality data must be checked before their use in order to guarantee the inputs for the methods used in modelling, monitoring, forecast, etc. To control their quality, data should be submitted to several conditions or tests. After this checking, data that are not flagged by any of the test is released as a plausible data. In this work, it has been performed a bibliographical research of quality control tests for the common meteorological variables (ambient temperature, relative humidity and wind speed) and for the usual solar radiometrical variables (horizontal global and diffuse components of the solar radiation and the beam normal component). The different tests have been grouped according to the variable and the average time period (sub-hourly, hourly, daily and monthly averages). The quality test may be classified as follows: • Range checks: test that verify values are within a specific range. There are two types of range checks, those based on extrema and those based on rare observations. • Step check: test aimed at detecting unrealistic jumps or stagnation in the time series. • Consistency checks: test that verify the relationship between two or more time series. The gathered quality tests are applicable for all latitudes as they have not been optimized regionally nor seasonably with the aim of being generic. They have been applied to ground measurements in several geographic locations, what

  11. Deep Space 1 Ion Engine Completed a 3-Year Journey

    NASA Technical Reports Server (NTRS)

    Sovey, James S.; Patterson, Michael J.; Rawlin, Vincent K.; Hamley, John A.

    2001-01-01

    A xenon ion engine and power processor system, which was developed by the NASA Glenn Research Center in partnership with the Jet Propulsion Laboratory and Boeing Electron Dynamic Devices, completed nearly 3 years of operation aboard the Deep Space 1 spacecraft. The 2.3-kW ion engine, which provided primary propulsion and two-axis attitude control, thrusted for more than 16,000 hr and consumed more than 70 kg of xenon propellant. The Deep Space 1 spacecraft was launched on October 24, 1998, to validate 12 futuristic technologies, including the ion-propulsion system. After the technology validation process was successfully completed, the Deep Space 1 spacecraft flew by the small asteroid Braille on July 29, 1999. The final objective of this mission was to encounter the active comet Borrelly, which is about 6 miles long. The ion engine was on a thrusting schedule to navigate the Deep Space 1 spacecraft to within 1400 miles of the comet. Since the hydrazine used for spacecraft attitude control was in short supply, the ion engine also provided two-axis attitude control to conserve the hydrazine supply for the Borrelly encounter. The comet encounter took place on September 22, 2001. Dr. Marc Rayman, project manager of Deep Space 1 at the Jet Propulsion Laboratory said, "Deep Space 1 plunged into the heart of the comet Borrelly and has lived to tell every detail of its spinetingling adventure! The images are even better than the impressive images of comet Halley taken by Europe's Giotto spacecraft in 1986." The Deep Space 1 mission, which successfully tested the 12 high-risk, advanced technologies and captured the best images ever taken of a comet, was voluntarily terminated on December 18, 2001. The successful demonstration of the 2-kW-class ion propulsion system technology is now providing mission planners with off-the-shelf flight hardware. Higher power, next generation ion propulsion systems are being developed for large flagship missions, such as outer planet

  12. Nonlinear stability of oscillatory core-annular flow: A generalized Kuramoto-Sivashinsky equation with time periodic coefficients

    NASA Technical Reports Server (NTRS)

    Coward, Adrian V.; Papageorgiou, Demetrios T.; Smyrlis, Yiorgos S.

    1994-01-01

    In this paper the nonlinear stability of two-phase core-annular flow in a pipe is examined when the acting pressure gradient is modulated by time harmonic oscillations and viscosity stratification and interfacial tension is present. An exact solution of the Navier-Stokes equations is used as the background state to develop an asymptotic theory valid for thin annular layers, which leads to a novel nonlinear evolution describing the spatio-temporal evolution of the interface. The evolution equation is an extension of the equation found for constant pressure gradients and generalizes the Kuramoto-Sivashinsky equation with dispersive effects found by Papageorgiou, Maldarelli & Rumschitzki, Phys. Fluids A 2(3), 1990, pp. 340-352, to a similar system with time periodic coefficients. The distinct regimes of slow and moderate flow are considered and the corresponding evolution is derived. Certain solutions are described analytically in the neighborhood of the first bifurcation point by use of multiple scales asymptotics. Extensive numerical experiments, using dynamical systems ideas, are carried out in order to evaluate the effect of the oscillatory pressure gradient on the solutions in the presence of a constant pressure gradient.

  13. AROME-WMED, a real-time mesoscale model designed for the HyMeX Special Observation Periods

    NASA Astrophysics Data System (ADS)

    Fourrié, N.; Bresson, É.; Nuret, M.; Jany, C.; Brousseau, P.; Doerenbecher, A.; Kreitz, M.; Nuissier, O.; Sevault, E.; Bénichou, H.; Amodei, M.; Pouponneau, F.

    2015-02-01

    During autumn 2012 and winter 2013, two Special Observation Periods (SOPs) of the Hydrological cycle in the Mediterranean Experiment (HyMeX) took place. For the preparatory studies and to support the instrument deployment during the field campaign, a dedicated version of the operational convective-scale AROME-France model was developed: the AROME-WMED model. It covers the western Mediterranean basin with a 48 h forecast range. It provided real time analyses and forecasts which were sent daily to the HyMeX operational centre to forecast high precipitation events and to help decision makers on the deployment of observation instruments. This paper presents the main features of this numerical weather prediction system in terms of data assimilation and forecast. Some specific data of the HyMeX SOP were assimilated in real time. The forecast skill of the AROME-WMED is then assessed with objective scores and compared to the operational AROME-France model, for both autumn 2012 (5 September to 6 November 2012) and winter 2013 (1 February to 15 March 2013) SOPs. The overall performance of AROME-WMED is good and similar to those of AROME-France for the 0 to 30 h common forecast range. The 24 to 48 h forecast range is of course less accurate but remains useful for scheduling observation deployment. The characteristics of parameters such as precipitation, temperature or humidity, are illustrated by one heavy precipitation case study that occurred over the south of Spain.

  14. Periodic Evolution of a Xe I Population in an Oscillatory Discharge Captured Through Time-Synchronized Laser Induced Fluorescence Techniques

    NASA Astrophysics Data System (ADS)

    Lucca Fabris, Andrea; Young, Christopher; Cappelli, Mark

    2014-10-01

    We track the evolution of the Xe I 6 s '[ 1 / 2 ] 1 - 6 p '[ 3 / 2 ] 2 (834.68 nm air) transition lineshape in a plasma discharge oscillating at 60 Hz. Two time-synchronized laser induced fluorescence techniques based on phase sensitive detection of the fluorescence signal are demonstrated, yielding consistent results. One approach used previously involves a sample-and-hold procedure that collects fluorescence signal at a particular phase in the oscillation period and holds the average value until the following sample. The second method is based on fast switching of the fluorescence signal; only the signal collected inside the acquisition gate is sent to a lock-in amplifier for processing. Both methods rely on modulating the exciting laser beam and the latter permits operation at a much higher frequency range with reduced spectral noise density. The maximum observed peak fluorescence intensity occurs at low discharge currents, although the peak intensity drops to zero at zero discharge current. The peak intensity also decreases at the discharge current maximum. Time-varying properties of the xenon neutrals are extracted from a lineshape analysis. This work is sponsored by the U.S. Air Force Office of Scientific Research with Dr. Mitat Birkan as program manager. CVY acknowledges support from the DOE NNSA Stewardship Science Graduate Fellowship under Contract DE-FC52-08NA28752.

  15. Primate HPT axis response to the peripheral kisspeptin challenge under different time periods of food restriction in monkeys.

    PubMed

    Wahab, F; Atika, B; Huma, T; Shahab, M

    2014-03-01

    Metabolism and reproduction are closely linked. Both long- and short-term fasting-induced metabolic deficiency suppresses reproductive function in mammals. Recently, we have shown that 48-h fasting-induced metabolic deficiency attenuates the reproductive axis responsiveness to peripheral kisspeptin injection in the sexually mature monkeys. But currently there is no data to show whether shorter time periods of fasting also alter the reproductive axis responsiveness to kisspeptin. Therefore, this study was aimed to examine the reproductive axis responsiveness to kisspeptin administration in the adult male rhesus monkey fasted for 12-, 18-, and 24h. Intravenous boli of vehicle (1 ml) and human kisspeptin-10 (KP10; 50 μg) were given to 5 intact sexually mature male rhesus monkeys in both fasting (12-, 18-, 24-h) and ad libitum feeding conditions. Specific immunoassays were used to determine plasma hormones concentrations. KP10 injection highly stimulated testosterone secretion in all conditions. However, mean testosterone concentrations in 3-h post-KP10 injection period were significantly (p<0.01) decreased in 18- and 24-h fasted monkeys when compared to 12-h fasted and fed monkeys. Moreover, 18- and 24-h fasting conditions also significantly (p<0.05) delayed the duration to the first significant increase in T levels after KP10 injection. Vehicle injection did not alter these parameters in any conditions. Present results indicate that 18- and 24-h fasting conditions suppressed the testosterone response to KP10 administration both in initiation and quantity. These results suggest that 18- and 24-h fasting-induced inhibition of the reproductive functions in the mature male macaque may partly involve attenuation in the reproductive axis responsiveness to endogenous kisspeptin stimulation.

  16. Orbit optimization and time delay interferometry for inclined ASTROD-GW formation with half-year precession-period

    NASA Astrophysics Data System (ADS)

    Wang, Gang; Ni, Wei-Tou

    2015-05-01

    ASTROD-GW (ASTROD [astrodynamical space test of relativity using optical devices] optimized for gravitational wave detection) is a gravitational-wave mission with the aim of detecting gravitational waves from massive black holes, extreme mass ratio inspirals (EMRIs) and galactic compact binaries together with testing relativistic gravity and probing dark energy and cosmology. Mission orbits of the 3 spacecrafts forming a nearly equilateral triangular array are chosen to be near the Sun-Earth Lagrange points L3, L4, and L5. The 3 spacecrafts range interferometrically with one another with arm length about 260 million kilometers. For 260 times longer arm length, the detection sensitivity of ASTROD-GW is 260 fold better than that of eLISA/NGO in the lower frequency region by assuming the same acceleration noise. Therefore, ASTROD-GW will be a better cosmological probe. In previous papers, we have worked out the time delay interferometry (TDI) for the ecliptic formation. To resolve the reflection ambiguity about the ecliptic plane in source position determination, we have changed the basic formation into slightly inclined formation with half-year precession-period. In this paper, we optimize a set of 10-year inclined ASTROD-GW mission orbits numerically using ephemeris framework starting at June 21, 2035, including cases of inclination angle with 0° (no inclination), 0.5°, 1.0°, 1.5°, 2.0°, 2.5°, and 3.0°. We simulate the time delays of the first and second generation TDI configurations for the different inclinations, and compare/analyse the numerical results to attain the requisite sensitivity of ASTROD-GW by suppressing laser frequency noise below the secondary noises. To explicate our calculation process for different inclination cases, we take the 1.0° as an example to show the orbit optimization and TDI simulation.

  17. Concentrations of Immunoglobulin G Antibodies Against Pertussis Toxin Does Not Decrease Over a Long Period of Time in Japan

    PubMed Central

    Sakakibara, Yumi; Ohtani, Yoshio; Jinta, Torahiko; Fujie, Toshihide; Miyazaki, Yasunari; Inase, Naohiko; Saito, Ryoichi; Akaza, Miho; Sasano, Tetsuo; Sumi, Yuki

    2016-01-01

    Objective Adult patients with pertussis rarely show typical symptoms, such as paroxysmal coughing, inspiratory “whoop”, or post-tussive vomiting. While a culture is regarded as the gold standard for diagnosis, the sensitivity is very low. Therefore, the diagnosis of pertussis in adults in clinical practice is mostly based on single-sample serology using an enzyme-linked immunosorbent assay (ELISA) with the pertussis toxin antigen. Various cut-off values for the anti-pertussis toxin IgG (PT-IgG) have been proposed. It has been reported that concentrations of PT-IgG fall below the defined cut-off about 4.5 months after infection on average, and within 1 year in most patients. We investigated the distribution and time course of the PT-IgG levels. Methods The data were collected from the medical records. Patients The study retrospectively identified subjects who had visited Ikebukuro Otani Clinic, which is a specialized clinic for patients with cough. We retrospectively reviewed 406 patients with PT-IgG measurements to investigate the age distribution of PT-IgG levels. The changes in PT-IgG levels over time were assessed in the 205 patients who had more than one PT-IgG measurement. Results PT-IgG levels were ≥100 EU/mL in more than 15% of subjects. The PT-IgG levels of a few subjects had diminished over a long period of time. Conclusion A PT-IgG level greater than the defined cut-off value simply indicates past infection or immunization in most subjects. As such, a single measurement of PT-IgG using the cut-off values might lead to overdiagnosis of pertussis. Further data collection and analysis are required. PMID:27853066

  18. AROME-WMED, a real-time mesoscale model designed for the HyMeX special observation periods

    NASA Astrophysics Data System (ADS)

    Fourrié, N.; Bresson, É.; Nuret, M.; Jany, C.; Brousseau, P.; Doerenbecher, A.; Kreitz, M.; Nuissier, O.; Sevault, E.; Bénichou, H.; Amodei, M.; Pouponneau, F.

    2015-07-01

    During autumn 2012 and winter 2013, two special observation periods (SOPs) of the HYdrological cycle in the Mediterranean EXperiment (HyMeX) took place. For the preparatory studies and to support the instrument deployment during the field campaign, a dedicated version of the operational convective-scale Application of Research to Operations at Mesoscale (AROME)-France model was developed: the AROME-WMED (West Mediterranean Sea) model. It covers the western Mediterranean basin with a 48 h forecast range. It provided real-time analyses and forecasts which were sent daily to the HyMeX operational centre to forecast high-precipitation events and to help decision makers on the deployment of meteorological instruments. This paper presents the main features of this numerical weather prediction system in terms of data assimilation and forecast. Some specific data of the HyMeX SOP were assimilated in real time. The forecast skill of AROME-WMED is then assessed with objective scores and compared to the operational AROME-France model, for both autumn 2012 (05 September to 06 November 2012) and winter 2013 (01 February to 15 March 2013) SOPs. The overall performance of AROME-WMED is good for the first HyMeX special observation period (SOP1) (i.e. mean 2 m temperature root mean square error (RMSE) of 1.7 °C and mean 2 m relative humidity RMSE of 10 % for the 0-30 h forecast ranges) and similar to those of AROME-France for the 0-30 h common forecast range (maximal absolute difference of 2 m temperature RMSE of 0.2 °C and 0.21 % for the 2 m relative humidity); conversely, for the 24-48 h forecast range it is less accurate (relative loss between 10 and 12 % in 2 m temperature and relative humidity RMSE, and equitable threat score (ETS) for 24 h accumulated rainfall), but it remains useful for scheduling observation deployment. The characteristics of parameters, such as precipitation, temperature or humidity, are illustrated by one heavy precipitation case study that occurred

  19. Development and implementation of the Clinical Tooth Shade Differentiation Course – an evaluation over 3 years

    PubMed Central

    Olms, Constanze; Haak, Rainer; Jakstat, Holger A.

    2016-01-01

    Objective: Tooth shade differentiation concerns the identification and classification of tooth shades. The objective of this project was to implement the Clinical Tooth Shade Differentiation Course in the preclinical stage of studies and to evaluate the students' perspective over a period of 3 years. Methodology: The course is planned for a duration of 10 weeks with two 45-minute sessions per semester week. The entire attendance time was 10:15 h. 2 lectures of 90 minutes each, 2 seminars of 60 min each and 2 teaching units with the phantom head and role playing took place. In addition to the various parameters of tooth shade, changes in tooth shade and the basics of dental esthetics, clinical procedures for manual and digital tooth shade determination were explained and practiced. 96% (69 of 72) of the students participated in the first evaluation in 2012/2013 (T1), and 68% of these were women. In the following year, 2013/2014 (T2), 92% (45 of 48 students) took part; 62% of these were women and 38% men. The 2014/2015 evaluation (T3) comprised 94% (45 of 48 students). Of these, 67% were women. Results: In the evaluation, the students gave the course a positive grade. The questions in "General/Organization" were given a mean (M) of 1.5 (SD=0.7) in T1 and T2 , and 1.2 (SD=0.3) in T3. The "Overall Assessment" yielded MT1=1.6 (SD=0.6), MT2=1.5 (SD=0.5) and MT3=1.1 (SD=0.3). In T1 and T2, the item "The instructor actively involved the students in the course" was given a mean of 2.1 (SD=0.9), and in T3 a mean of 1.2 (SD=0.5). Conclusions: The course presented here conceptually shows how practical dental skills can be taught in a theoretical and clinical context. Educational objectives from the role of a dental expert were taken from the national competence-based catalog of educational objectives for dentistry and can also be supplemented. The objectives can be transferred to other dental faculties. PMID:26958650

  20. Climate regime shifts in paleoclimate time series from the Yucatán Peninsula: from the Preclassic to Classic period

    NASA Astrophysics Data System (ADS)

    Polanco Martínez, Josue M.; Medina-Elizalde, Martin; Burns, Stephen J.; Jiang, Xiuyang; Shen, Chuan-Chou

    2015-04-01

    It has been widely accepted by the paleoclimate and archaeology communities that extreme climate events (especially droughts) and past climate change played an important role in the cultural changes that occurred in at least some parts of the Maya Lowlands, from the Pre-Classic (2000 BC to 250 AD) to Post-Classic periods (1000 to 1521 AD) [1, 2]. In particular, a large number of studies suggest that the decline of the Maya civilization in the Terminal Classic Period was greatly influenced by prolonged severe drought events that probably triggered significant societal disruptions [1, 3, 4, 5]. Going further on these issues, the aim of this work is to detect climate regime shifts in several paleoclimate time series from the Yucatán Peninsula (México) that have been used as rainfall proxies [3, 5, 6, 7]. In order to extract information from the paleoclimate data studied, we have used a change point method [8] as implemented in the R package strucchange, as well as the RAMFIT method [9]. The preliminary results show for all the records analysed a prominent regime shift between 400 to 200 BCE (from a noticeable increase to a remarkable fall in precipitation), which is strongest in the recently obtained stalagmite (Itzamna) delta18-O precipitation record [7]. References [1] Gunn, J. D., Matheny, R. T., Folan, W. J., 2002. Climate-change studies in the Maya area. Ancient Mesoamerica, 13(01), 79-84. [2] Yaeger, J., Hodell, D. A., 2008. The collapse of Maya civilization: assessing the interaction of culture, climate, and environment. El Niño, Catastrophism, and Culture Change in Ancient America, 197-251. [3] Hodell, D. A., Curtis, J. H., Brenner, M., 1995. Possible role of climate in the collapse of Classic Maya civilization. Nature, 375(6530), 391-394. [4] Aimers, J., Hodell, D., 2011. Societal collapse: Drought and the Maya. Nature 479(7371), 44-45 (2011). [5] Medina-Elizalde, M., Rohling, E. J., 2012. Collapse of Classic Maya civilization related to modest reduction

  1. Summary of Time Period-Based and Other Approximation Methods for Determining the Capacity Value of Wind and Solar in the United States: September 2010 - February 2012

    SciTech Connect

    Rogers, J.; Porter, K.

    2012-03-01

    This paper updates previous work that describes time period-based and other approximation methods for estimating the capacity value of wind power and extends it to include solar power. The paper summarizes various methods presented in utility integrated resource plans, regional transmission organization methodologies, regional stakeholder initiatives, regulatory proceedings, and academic and industry studies. Time period-based approximation methods typically measure the contribution of a wind or solar plant at the time of system peak - sometimes over a period of months or the average of multiple years.

  2. Psychological Distress in Healthy Low-Risk First-Time Mothers during the Postpartum Period: An Exploratory Study

    PubMed Central

    Carter, Patricia; Price, Larry R.; Champion, Jane Dimmitt; Nichols, Francine

    2017-01-01

    Psychological distress, defined as depression, anxiety, and insomnia in this study, can occur following the birth of a baby as new mothers, in addition to marked physiological changes, are faced with adapting to new roles and responsibilities. We investigated the cooccurrence of stress, depression, anxiety, and insomnia in mothers during the postpartum period; tested the feasibility of study methods and procedures for use in this population; and identified new mothers interest in using cranial electrotherapy stimulation (CES) as an intervention for reducing psychological distress. We recruited healthy, low-risk, English speaking first-time mothers, ages 18–32 years, with healthy babies (N = 33), within 12 months of an uncomplicated birth. Participants completed the PSS, HAM-D14, HAM-A17, and PSQI19. No problems were encountered with study procedures. Mothers reported a high interest (4.9) in the potential use of CES to treat or prevent the occurrence of psychological distress. All participants (N = 33) reported moderate levels of depression and anxiety, while 75.8% (n = 25) reported insomnia. PSS scores were within the norms for healthy women. Further research is recommended to investigate if our findings can be replicated or if different patterns of associations emerge. Implications for clinical practice are addressed. PMID:28191350

  3. Numerical modelling of the physical factors that affect mass transport in the vasculature at early time periods.

    PubMed

    Denny, William J; Walsh, Michael T

    2014-03-01

    Coronary artery disease results in blockages or narrowing of the artery lumen. Drug eluting stents were developed to replace bare metal stents in an effort to combat re-blocking of the lumen. A key element in determining the therapeutic success of a drug eluting stent is an in-depth understanding of the physical factors that affect mass transport of the drug into the arterial wall, over early time periods. The numerical models developed within this study focus on assessing the influence of a host of physical factors that either facilitate or impede therapeutic drug delivery into the arterial wall from the unit cell of an idealised stent. This study demonstrates that model reduction strategies to 2D and 1D can still adequately represent a 3D curved arterial wall and strut polymer coating, respectively, using an idealistic stent geometry. It was shown that the level of strut compression can have a significant impact on therapeutic drug delivery in the arterial wall.

  4. Hsp70 and HSF-1 expression is altered in the tissues of pigs transported for various periods of times.

    PubMed

    Zhang, Miao; Yue, Zhenhua; Liu, Zhijun; Islam, Ali; Rehana, Buriro; Tang, Shu; Bao, Endong; Hartung, Jörg

    2012-09-01

    The aim of this study was to assess changes of Hsp70 and HSF-1 protein and mRNA expression in stress-sensitive organs of pigs during transportation for various periods of time. Twenty pigs were randomly divided into four groups (0 h, 1 h, 2 h, and 4 h of transportation). A significant increased activity of AST and CK was observed after 1 h and 2 h of transportation. Histopathological changes in the heart, liver, and stomach indicated that these organs sustained different degrees of injury. Hsp70 protein expression in the heart and liver of transported pigs did not change significantly while it increased significantly (p < 0.05) in the stomach. Hsp70 mRNA levels decreased significantly (p < 0.05) in the heart after 4 h of transportation. However, mRNA expression increased significantly in the liver after 1 (p < 0.05) and 4 h (p < 0.01) of transportation, and increased significantly in the stomach of the transported pigs after 1, 4 (p < 0.01), and 2 h (p < 0.05). HSF-1 levels were reduced at 1 and 4 h (p < 0.05) only in the hearts of transported pigs. These results indicate that Hsp70 mediates distinct stress-related functions in different tissues during transportation.

  5. Differences in maternal behavior and development of their pups depend on the time of methamphetamine exposure during gestation period.

    PubMed

    Malinová-Ševčíková, M; Hrebíčková, I; Macúchová, E; Nová, E; Pometlová, M; Šlamberová, R

    2014-01-01

    The present study examined the hypothesis that the extension of noxious effect of methamphetamine (MA) on maternal behavior and postnatal development on the pups may differ in dependence with time of application. Female rats were injected with MA (5 mg/kg) or saline during first (embryonic day (ED) 1-11) or second (ED 12-22) half of gestation. Our results demonstrated that MA exposure on ED 12-22 led to decreased birth weight and weight gained during lactation period relative to rats treated on ED 1-11. Both sexes treated prenatally with MA on ED 1-11 opened eyes earlier compared to animals treated on ED 12-22. As a matter of sensorimotor development application of MA on ED 1-11 impaired the righting reflex, while MA exposure on ED 12-22 impaired the performance of beam balance test in male rats. There were no differences in maternal behavior. Therefore, it seems that MA exposure in the first half of the gestation impaired the early sensorimotor development that is under control of the brain stem, while the MA exposure in the second half of gestation affected the beam balance performance that is dependent on the function of the cerebellum.

  6. [Sodium cromoglycate in the treatment of food hypersensitivity in children under 3 years of age].

    PubMed

    Zur, E; Kaczmarski, M

    2001-09-01

    Dietary elimination is a treatment of first choice in food hypersensitivity. Such therapy is not always enough to stop the disease and introduction of pharmacological treatment is necessary. In prevention and long term treatment antiallergic drugs are recommended. The aim of the study was to assess efficacy and safety of oral sodium cromoglycate in treatment of food hypersensitivity in the youngest children. In our study we examined: the group of 25 children aged 6 months-3 years treated with oral cromolyn sodium during the period 4-20 weeks and 29 children aged 6 months-3 years treated with ketotifen. Symptoms from skin, digestive and respiratory tract, behaviour status were evaluated for drugs efficacy. Cromolyn and ketotifen effected a significant decrease in total symptoms score. The treatment was well tolerated. No serious side effects were noted. The incidents of skin rash, disquiet during the night, diarrhoea and urticaria were only 8 percent. Sodium cromoglycate is safe and effective drug in treatment of food allergy in children; specially in symptoms from gastrointestinal tract and multi-organs allergy.

  7. [3-year results of clinical and immunological monitoring of patients with multiple sclerosis treated by copaxone].

    PubMed

    Orlova, Iu Iu; Alifirova, V M; Cherdyntseva, N V; Zagrebina, I A; Bychkova, I V

    2005-01-01

    Tipe 1 T-helper cells are of importance in development of multiple sclerosis (MS). Copaxone (TEVA, Israel) is one of the preventive drugs, which modifies T-helpers activity. Thirty-three patients with MS were treated by copaxone for 2 years and 13 patients--for 3 years. Clinical and immunological parameters were examined: amount of CD3+, CD4+, CD8+, CD16+, CD22+, CD95+, CD25+ lymphocytes, HLA-D+ cells, IgG, IgA, IgM and phagocytosis. During the treatment course, mean rate of relapses decreased from the pretreatment value from 1.26 +/- 0.11 to 0.59 +/- 0.11 in the first year and 0.28 +/- 0.07 in the second one. After 3 years no relapses were observed in 13 patients. Relapse rate was the highest in the first 3-6 months. But after 3 months there was an increase of CD22+ cells that persisted for all the period of the study. After a year of the treatment, a level of IgM, IgG, IgA and CD95+ cells has raised significantly, with decreasing of a number of CD4+ and CD8+ cells. The authors suggest that immunological shift is related to mechanism of copaxone action determining its positive effect i.e. reducing of frequency of MS relapses.

  8. 3D imaging of cone photoreceptors over extended time periods using optical coherence tomography with adaptive optics

    NASA Astrophysics Data System (ADS)

    Kocaoglu, Omer P.; Lee, Sangyeol; Jonnal, Ravi S.; Wang, Qiang; Herde, Ashley E.; Besecker, Jason; Gao, Weihua; Miller, Donald T.

    2011-03-01

    Optical coherence tomography with adaptive optics (AO-OCT) is a highly sensitive, noninvasive method for 3D imaging of the microscopic retina. The purpose of this study is to advance AO-OCT technology by enabling repeated imaging of cone photoreceptors over extended periods of time (days). This sort of longitudinal imaging permits monitoring of 3D cone dynamics in both normal and diseased eyes, in particular the physiological processes of disc renewal and phagocytosis, which are disrupted by retinal diseases such as age related macular degeneration and retinitis pigmentosa. For this study, the existing AO-OCT system at Indiana underwent several major hardware and software improvements to optimize system performance for 4D cone imaging. First, ultrahigh speed imaging was realized using a Basler Sprint camera. Second, a light source with adjustable spectrum was realized by integration of an Integral laser (Femto Lasers, λc=800nm, ▵λ=160nm) and spectral filters in the source arm. For cone imaging, we used a bandpass filter with λc=809nm and ▵λ=81nm (2.6 μm nominal axial resolution in tissue, and 167 KHz A-line rate using 1,408 px), which reduced the impact of eye motion compared to previous AO-OCT implementations. Third, eye motion artifacts were further reduced by custom ImageJ plugins that registered (axially and laterally) the volume videos. In two subjects, cone photoreceptors were imaged and tracked over a ten day period and their reflectance and outer segment (OS) lengths measured. High-speed imaging and image registration/dewarping were found to reduce eye motion to a fraction of a cone width (1 μm root mean square). The pattern of reflections in the cones was found to change dramatically and occurred on a spatial scale well below the resolution of clinical instruments. Normalized reflectance of connecting cilia (CC) and OS posterior tip (PT) of an exemplary cone was 54+/-4, 47+/-4, 48+/-6, 50+/-5, 56+/-1% and 46+/-4, 53+/-4, 52+/-6, 50+/-5, 44

  9. Time Orientation of Young Male First Offenders as a Function of Period of Imprisonment and Race. Criminal Justice Monograph Volume VI, Number 1.

    ERIC Educational Resources Information Center

    Rogan, Paul J.

    This research attempted to identify differences, or lack of them, in time orientation of Caucasian, Black and Chicano young male first offenders at various periods of imprisonment; beginning, middle, and end. The instrument that was chosen to measure time orientation was a combination of two questionnaires--the Time Competence scale of the…

  10. 31 CFR 256.33 - For what period of time is interest computed under 31 U.S.C. 1304(b)?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false For what period of time is interest computed under 31 U.S.C. 1304(b)? 256.33 Section 256.33 Money and Finance: Treasury Regulations Relating to....33 For what period of time is interest computed under 31 U.S.C. 1304(b)? Interest is computed...

  11. A 3-Year Climatology of Cloud and Radiative Properties Derived from GOES-8 Data Over the Southern Great Plains

    NASA Technical Reports Server (NTRS)

    Khaiyer, M. M.; Rapp, A. D.; Doelling, D. R.; Nordeen, M. L.; Minnis, P.; Smith, W. L., Jr.; Nguyen, L.

    2001-01-01

    While the various instruments maintained at the Atmospheric Radiation Measurement (ARM) Program Southern Great Plains (SGP) Central Facility (CF) provide detailed cloud and radiation measurements for a small area, satellite cloud property retrievals provide a means of examining the large-scale properties of the surrounding region over an extended period of time. Seasonal and inter-annual climatological trends can be analyzed with such a dataset. For this purpose, monthly datasets of cloud and radiative properties from December 1996 through November 1999 over the SGP region have been derived using the layered bispectral threshold method (LBTM). The properties derived include cloud optical depths (ODs), temperatures and albedos, and are produced on two grids of lower (0.5 deg) and higher resolution (0.3 deg) centered on the ARM SGP CF. The extensive time period and high-resolution of the inner grid of this dataset allows for comparison with the suite of instruments located at the ARM CF. In particular, Whole-Sky Imager (WSI) and the Active Remote Sensing of Clouds (ARSCL) cloud products can be compared to the cloud amounts and heights of the LBTM 0.3 deg grid box encompassing the CF site. The WSI provides cloud fraction and the ARSCL computes cloud fraction, base, and top heights using the algorithms by Clothiaux et al. (2001) with a combination of Belfort Laser Ceilometer (BLC), Millimeter Wave Cloud Radar (MMCR), and Micropulse Lidar (MPL) data. This paper summarizes the results of the LBTM analysis for 3 years of GOES-8 data over the SGP and examines the differences between surface and satellite-based estimates of cloud fraction.

  12. A time period study on the efficiency of luminol in the detection of bloodstains concealed by paint on different surfaces.

    PubMed

    Nagesh, Deepthi; Ghosh, Shayani

    2017-02-11

    Forensic Science is the application of science to the criminal and civil laws that are enforced by police agencies in a criminal justice system. It is a science which relies on physical evidence; one of the important physical evidences being blood. The purpose of this research was to determine the efficacy of luminol reagent in detecting bloodstains on different surfaces, concealed by multiple layers of paint, over a period of time and also to compare the intensities of chemiluminescence exhibited by them. In this study, dry wall, wooden planks and metal surfaces were identified as commonly encountered surfaces at crime scenes and hence 25 of each surface were simulated and blood was spattered, which were then concealed by progressive layers of paint specific to each surface. Thereafter, each surface was critically observed for the intensity of chemiluminescence, following the application of luminol and the results were documented as photographs. The research was conducted for duration of 50 days, in order to study the effect of ageing of concealment upon detection of bloodstains using luminol. Varying intensities of chemiluminescence were displayed by all the three simulated surfaces deposited with paint over bloodstains up to three layers of concealment, depending on the nature of the surface which were captured using photography. The highest intensity of chemiluminescence was shown by concealed bloodstains on dry wall and metal surfaces, despite the number of layers of concealment. However, an increase in the number of layers of concealment produced a significant decrease in the intensity of chemiluminescenece displayed by the bloodstains concealed by paint upon reacting with luminol on metal sheets, which was not found to be uniform and consistent on the other surfaces. These findings highlight the fact that bloodstains concealed by paint could be effectively detected by luminol reagent, despite the nature and ageing of concealment and thereby provide a lead to

  13. Depression and suicidality during the postpartum period after first time deliveries, active component service women and dependent spouses, U.S. Armed Forces, 2007-2012.

    PubMed

    Do, Tai; Hu, Zheng; Otto, Jean; Rohrbeck, Patricia

    2013-09-01

    Although suicide is a leading cause of death among new mothers during the postpartum period, there has been limited research on self-harm in the postpartum period and associated risk factors. One potential risk factor for suicidality (completed suicides, suicide attempts, and suicide ideation including thoughts of self harm) during the postpartum period is postpartum depression (PPD). In this study of women who gave birth for the first time between 1 January 2007 and 31 December 2011, 5,267 (9.9% of all who delivered) active component service women and 10,301 (8.2%) dependent spouses received incident PPD diagnoses during the one year postpartum period; 213 (0.4%) service women and 221 (0.2%) dependent spouses were diagnosed with incident suicidality. After adjusting for the effects of other covariates, service women with PPD had 42.2 times the odds to be diagnosed with suicidality in the postpartum period compared to service women without PPD; dependent spouses with PPD had 14.5 times the odds compared to those without PPD. The findings of this report suggest that a history of mental disorders was common among service women and dependent spouses with PPD in the postpartum period, and, in turn, PPD was a strong predictor for suicidality in the postpartum period. These results emphasize the importance of PPD screening during the postpartum period. They also suggest that additional focused screening for suicidal behavior among those already diagnosed with PPD may be warranted.

  14. Analysis of global O(t(-α)) stability and global asymptotical periodicity for a class of fractional-order complex-valued neural networks with time varying delays.

    PubMed

    Rakkiyappan, R; Sivaranjani, R; Velmurugan, G; Cao, Jinde

    2016-05-01

    In this paper, the problem of the global O(t(-α)) stability and global asymptotic periodicity for a class of fractional-order complex-valued neural networks (FCVNNs) with time varying delays is investigated. By constructing suitable Lyapunov functionals and a Leibniz rule for fractional differentiation, some new sufficient conditions are established to ensure that the addressed FCVNNs are globally O(t(-α)) stable. Moreover, some sufficient conditions for the global asymptotic periodicity of the addressed FCVNNs with time varying delays are derived, showing that all solutions converge to the same periodic function. Finally, numerical examples are given to demonstrate the effectiveness and usefulness of our theoretical results.

  15. Mental Health Diagnoses 3 Years After Receiving or Being Denied an Abortion in the United States

    PubMed Central

    Neuhaus, John M.; Foster, Diana G.

    2015-01-01

    Objectives. We set out to assess the occurrence of new depression and anxiety diagnoses in women 3 years after they sought an abortion. Methods. We conducted semiannual telephone interviews of 956 women who sought abortions from 30 US facilities. Adjusted multivariable discrete-time logistic survival models examined whether the study group (women who obtained abortions just under a facility’s gestational age limit, who were denied abortions and carried to term, who were denied abortions and did not carry to term, and who received first-trimester abortions) predicted depression or anxiety onset during seven 6-month time intervals. Results. The 3-year cumulative probability of professionally diagnosed depression was 9% to 14%; for anxiety it was 10% to 15%, with no study group differences. Women in the first-trimester group and women denied abortions who did not give birth had greater odds of new self-diagnosed anxiety than did women who obtained abortions just under facility gestational limits. Conclusions. Among women seeking abortions near facility gestational limits, those who obtained abortions were at no greater mental health risk than were women who carried an unwanted pregnancy to term. PMID:26469674

  16. Change in messa di voce characteristics during 3 years of classical singing training at the tertiary level.

    PubMed

    Ferguson, Sam; Kenny, Dianna T; Mitchell, Helen F; Ryan, Maree; Cabrera, Densil

    2013-07-01

    A 3-year longitudinal study was conducted to investigate changes in vocal quality as a result of singing training at a tertiary level conservatorium in Australia. Singers performed a messa di voce (MDV) at intervals of 6 months over the 3-year period of training. The study investigated the evolving acoustic features of the singers' voices exhibited during the MDV, including sound pressure level (SPL), short-term energy ratio (STER), duration, and vibrato parameters of the fundamental frequency (F0), SPL, and STER. The maximum SPL exhibited a marginal systematic increase over the training period, but the maximum STER did not systematically change. F0 vibrato extent increased significantly, whereas the extent of SPL and STER vibrato did not change significantly.

  17. 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

  18. Emotion Situation Knowledge and Autobiographical Memory in Chinese, Immigrant Chinese, and European American 3-Year-Olds

    ERIC Educational Resources Information Center

    Wang, Qi; Hutt, Rachel; Kulkofsky, Sarah; McDermott, Melissa; Wei, Ruohong

    2006-01-01

    This study examined the influence of children's emotion situation knowledge (EK) on their autobiographical memory ability at both group and individual levels. Native Chinese, Chinese immigrant, and European American 3-year-old children participated (N = 189). During a home visit, children recounted 2 personal memories of recent, 1-time events with…

  19. Does attention constrain developmental trajectories in fragile x syndrome? A 3-year prospective longitudinal study.

    PubMed

    Cornish, Kim; Cole, Victoria; Longhi, Elena; Karmiloff-Smith, Annette; Scerif, Gaia

    2012-03-01

    Basic attentional processes and their impact on developmental trajectories in fragile X syndrome were assessed in a 3-year prospective study. Although fragile X syndrome is a monogenic X-linked disorder, there is striking variability in outcomes even in young boys with the condition. Attention is a key factor constraining interactions with the environment, so it is a perfect candidate to predict trajectories in cognitive and behavioral outcomes. In this study, 48 boys with fragile X syndrome were assessed 3 times over 24 months. Although nonverbal IQ declined, there were significant improvements in nonverbal growth scores and in cognitive attention. In contrast, behavioral difficulties (i.e., autistic symptomatology, hyperactivity-inattention) remained stable over this time frame. Attentional markers in the visual and auditory modalities predicted intellectual abilities and classroom behavior, whereas auditory markers alone predicted autistic symptomatology.

  20. AN EXTENDED AND MORE SENSITIVE SEARCH FOR PERIODICITIES IN ROSSI X-RAY TIMING EXPLORER/ALL-SKY MONITOR X-RAY LIGHT CURVES

    SciTech Connect

    Levine, Alan M.; Bradt, Hale V.; Chakrabarty, Deepto; Corbet, Robin H. D.; Harris, Robert J. E-mail: hale@space.mit.edu E-mail: robin.corbet@nasa.gov

    2011-09-01

    We present the results of a systematic search in {approx}14 years of Rossi X-ray Timing Explorer All-Sky Monitor (ASM) data for evidence of periodicities. Two variations of the commonly used Fourier analysis search method have been employed to significantly improve upon the sensitivity achieved by Wen et al. in 2006, who also searched for periodicities in ASM data. In addition, the present search is comprehensive in terms of sources studied and frequency range covered, and has yielded the detection of the signatures of the orbital periods of eight low-mass X-ray binary systems and of ten high-mass X-ray binaries not listed in the tables of Wen et al. Orbital periods, epochs, signal amplitudes, modulation fractions, and folded light curves are given for each of these systems. Seven of the orbital periods are the most precise reported to date. In the course of this work, the 18.545 day orbital period of IGR J18483-0311 was co-discovered, and the first detections in X-rays were made of the {approx}3.9 day orbital period of LMC X-1 and the {approx}3.79 hr orbital period of 4U 1636-536. The results inform future searches for orbital and other periodicities in X-ray binaries.

  1. Sticking out and fitting in: culture-specific predictors of 3-year-olds' autobiographical memories during joint reminiscing.

    PubMed

    Schröder, Lisa; Kärtner, Joscha; Keller, Heidi; Chaudhary, Nandita

    2012-12-01

    The present study investigates the relationship between mother-child interaction styles with 19 months and children's autobiographical memory with 3 years of age in two cultural contexts: New Delhi, India (n = 25) and Berlin, Germany (n = 33). Results demonstrate similarities as well as culture specificities. In both contexts, maternal elaborations during reminiscing were related to children's memory contributions. Over time, maternal support for toddlers' self-expression during free play at 19 months predicted their children's memory elaborations at 3 years in the Berlin context. In the Delhi context, toddlers' willingness to carry out their mothers' requests at 19 months predicted their memory elaborations at 3 years. These results suggest different motivational bases underlying children's autobiographical memory contributions during mother-child reminiscing related to different cultural orientations.

  2. Preventing Pregnancy in High School Students: Observations From a 3-Year Longitudinal, Quasi-Experimental Study

    PubMed Central

    Dierschke, Nicole; Lowe, Diana; Plastino, Kristen

    2016-01-01

    Objectives. To assess whether a sexual health education intervention reduces pregnancy rates in high school students. Methods. We performed a secondary analysis of a 3-year quasi-experimental study performed in South Texas from 2011 to 2015 in which 1437 students without a history of pregnancy at baseline were surveyed each fall and spring. Potentially confounding risk factors considered included sexual behaviors, intentions, and demographics. The outcome measure was self-reported pregnancy status for male and female students. We performed analyses for male and female students using separate discrete time-to-event models. Results. We found no difference in pregnancy rates between intervention and comparison students within the first 3 years of high school. Female and male students in the intervention groups had pregnancy hazard ratios of, respectively, 1.62 (95% CI = 0.9, 2.61; P = .1) and 0.78 (95% CI = 0.44, 1.48; P = .4) relative to the comparison groups. Conclusions. The educational intervention had no impact on the pregnancy rate. Social media tools in pregnancy prevention programs should be adaptive to new technologies and rapidly changing adolescent preferences for these services. PMID:27689503

  3. The relation between student motivation and student grades in physical education: A 3-year investigation.

    PubMed

    Barkoukis, V; Taylor, I; Chanal, J; Ntoumanis, N

    2014-10-01

    Enhancing students' academic engagement is the key element of the educational process; hence, research in this area has focused on understanding the mechanisms that can lead to increased academic engagement. The present study investigated the relation between motivation and grades in physical education (PE) employing a 3-year longitudinal design. Three hundred fifty-four Greek high school students participated in the study. Students completed measures of motivation to participate in PE on six occasions; namely, at the start and the end of the school year in the first, second, and third year of junior high school. Students' PE grades were also recorded at these time points. The results of the multilevel growth models indicated that students' PE grades increased over the 3 years and students had better PE grades at the end of each year than at the beginning of the subsequent year. In general, students and classes with higher levels of controlling motivation achieved lower PE grades, whereas higher levels of autonomous motivation were associated with higher PE grades. These findings provide new insight on the associations between class- and individual-level motivation with objectively assessed achievement in PE.

  4. Effects of timing and duration of test period and diet type on intake and feed efficiency of Charolais-sired cattle.

    PubMed

    Cassady, C J; Felix, T L; Beever, J E; Shike, D W

    2016-11-01

    Objectives of this experiment were to: 1) determine appropriate test length, timing, and repeatability of DMI, ADG, and efficiency over different biological time points; 2) determine the efficacy of using decoupled performance and intake data to generate accurate feed efficiency measures; and 3) determine the relationship between forage-and grain-feed efficiency measures. Over 2 yr, Charolais crossbred heifers ( = 308) and steers ( = 320) were fed for two 70 d periods and DMI, ADG, and 12th rib fat thickness were recorded. Steers were fed grain-based diets during the growing and finishing periods to determine the effects of test period and timing on DMI and feed efficiency. Heifers were fed forage during the growing period and grain during the finishing period to test the effect of diet type on measures of DMI and feed efficiency. For each 70 d test period, individual DMI was recorded using the GrowSafe (Airdrie, AB) system. Residual feed intake (RFI) was calculated for each test period. Total feeding period ADG (FP_ADG) was calculated for steers by regressing all weights taken from feedlot arrival to final BW, which was calculated by dividing HCW by a standard dressing percentage (63%). Dry matter intake and RFI were correlated (r 0.56; < 0.01, and 0.63; < 0.01, respectively) for the growing and finishing periods of grain-fed steers. Average daily gain was not repeatable ( = 0.11; 0.06) across both test periods for steers. However, growing and finishing ADG were correlated ( = 0.58; < 0.01, and = 0.69; < 0.01, respectively) to FP_ADG. To assess the potential of shortening the intake test, DMI was analyzed in 7 d increments for grain-fed steers during the growing and finishing periods. Regardless of test length, from 7 to 70 d, DMI was strongly correlated ( ≥ 0.87; < 0.01) to total DMI during the growing period. Heifer forage DMI was correlated ( = 0.58; < 0.01) to grain DMI; subsequently, forage and grain RFI were moderately correlated ( = 0.40; < 0.01). This

  5. Global O(t(-α)) stability and global asymptotical periodicity for a non-autonomous fractional-order neural networks with time-varying delays.

    PubMed

    Chen, Boshan; Chen, Jiejie

    2016-01-01

    The present paper studies global O(t(-α)) stability and global asymptotical periodicity for a non-autonomous fractional-order neural networks with time-varying delays (FDNN). Firstly, some sufficient conditions are established to ensure that a non-autonomous FDNN is global O(t(-α)) stable based on a new Lyapunov function method and Leibniz rule for fractional differentiation. Next it is shown that the periodic or autonomous FDNN cannot generate exactly nonconstant periodic solution under any circumstances. Finally, we show that all solutions converge to a same periodic function for a periodic FDNN by using a fractional-order differential inequality technique. Our issues, methods and results are all new.

  6. Rates of mutation and host transmission for an Escherichia coli clone over 3 years.

    PubMed

    Reeves, Peter R; Liu, Bin; Zhou, Zhemin; Li, Dan; Guo, Dan; Ren, Yan; Clabots, Connie; Lan, Ruiting; Johnson, James R; Wang, Lei

    2011-01-01

    Although over 50 complete Escherichia coli/Shigella genome sequences are available, it is only for closely related strains, for example the O55:H7 and O157:H7 clones of E. coli, that we can assign differences to individual evolutionary events along specific lineages. Here we sequence the genomes of 14 isolates of a uropathogenic E. coli clone that persisted for 3 years within a household, including a dog, causing a urinary tract infection (UTI) in the dog after 2 years. The 20 mutations observed fit a single tree that allows us to estimate the mutation rate to be about 1.1 per genome per year, with minimal evidence for adaptive change, including in relation to the UTI episode. The host data also imply at least 6 host transfer events over the 3 years, with 2 lineages present over much of that period. To our knowledge, these are the first direct measurements for a clone in a well-defined host community that includes rates of mutation and host transmission. There is a concentration of non-synonymous mutations associated with 2 transfers to the dog, suggesting some selection pressure from the change of host. However, there are no changes to which we can attribute the UTI event in the dog, which suggests that this occurrence after 2 years of the clone being in the household may have been due to chance, or some unknown change in the host or environment. The ability of a UTI strain to persist for 2 years and also to transfer readily within a household has implications for epidemiology, diagnosis, and clinical intervention.

  7. 45 CFR 287.55 - What time frames and guidelines apply regarding the obligation and liquidation periods for NEW...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... be returned to the Federal government through the issuance of a negative grant award. Unobligated..., i.e., no later than July 30. This report is called the interim financial report. (b) A Tribe must... the close of the liquidation period will be returned to the Federal government through the issuance...

  8. Primed acclimation of cultivated peanut (Arachis hypogaea L.) through the use of deficit irrigation timed to crop developmental periods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water-deficits and high temperatures are the predominant factors limiting peanut production across the U.S., either because of regional aridity or untimely rainfall events during crucial crop developmental periods. In the southern High Plains of west Texas and eastern New Mexico, low average annual ...

  9. Time Series Analysis of Sexual Assault Case Characteristics and the 2007–2008 Period of Post-Election Violence in Kenya

    PubMed Central

    Anastario, Michael P.; Adhiambo Onyango, Monica; Nyanyuki, Joan; Naimer, Karen; Muthoga, Rachel; Sirkin, Susannah; Barrick, Kelle; van Hasselt, Martijn; Aruasa, Wilson; Kibet, Cynthia; Omollo, Grace

    2014-01-01

    Background Following the declaration that President Mwai Kibaki was the winner of the Kenyan presidential election held on December 27, 2007, a period of post-election violence (PEV) took place. In this study, we aimed to identify whether the period of PEV in Kenya was associated with systematic changes in sexual assault case characteristics. Methods and Findings Medical records of 1,615 patients diagnosed with sexual assault between 2007 and 2011 at healthcare facilities in Eldoret (n = 569), Naivasha (n = 534), and Nakuru (n = 512) were retrospectively reviewed to examine characteristics of sexual assault cases over time. Time series and linear regression were used to examine temporal variation in case characteristics relative to the period of post-election violence in Kenya. Key informant interviews with healthcare workers at the sites were employed to triangulate findings. The time series of sexual assault case characteristics at these facilities were examined, with a specific focus on the December 2007–February 2008 period of post-election violence. Prais-Winsten estimates indicated that the three-month period of post-election violence was associated with a 22 percentage-point increase in cases where survivors did not know the perpetrator, a 20 percentage-point increase in cases with more than one perpetrator, and a 4 percentage-point increase in cases that had evidence of abdominal injury. The post-election violence period was also associated with an 18 percentage-point increase in survivors waiting >1 month to report to a healthcare facility. Sensitivity analyses confirmed that these characteristics were specific to the post-election violence time period. Conclusion These results demonstrate systematic patterns in sexual assault characteristics during the PEV period in Kenya. PMID:25170917

  10. Eudaimonic growth: Narrative growth goals predict increases in ego development and subjective well-being 3 years later.

    PubMed

    Bauer, Jack J; McAdams, Dan P

    2010-07-01

    We examine (a) the normative course of eudaimonic well-being in emerging adulthood and (b) whether people's narratives of major life goals might prospectively predict eudaimonic growth 3 years later. We define eudaimonic growth as longitudinal increases in eudaimonic well-being, which we define as the combination of psychosocial maturity and subjective well-being (SWB). College freshmen and seniors took measures of ego development (ED; to assess maturity; Loevinger, 1976) and SWB at Time 1 (T1) and again 3 years later (Time 2). ED levels increased longitudinally across that time for men and T1 freshmen, but SWB levels did not change. Participants also wrote narratives of 2 major life goals at T1 that were coded for an explicit emphasis on specific kinds of personal growth. Participants' intellectual-growth goals (especially agentic ones) predicted increases in ED 3 years later, whereas participants' socioemotional-growth goals (especially communal ones) predicted increases in SWB 3 years later. These findings were independent of the effects of Big Five personality traits-notably conscientiousness, which on its own predicted increases in SWB. We discuss (a) emerging adulthood as the last stop for normative eudaimonic growth in modern society and (b) empirical and theoretical issues surrounding the relations among narrative identity, life planning, dispositional traits, eudaimonia, and 2 paths of personal growth.

  11. Existence and global exponential stability of almost periodic solution for cellular neural networks with variable coefficients and time-varying delays.

    PubMed

    Jiang, Haijun; Zhang, Long; Teng, Zhidong

    2005-11-01

    In this paper, we study cellular neural networks with almost periodic variable coefficients and time-varying delays. By using the existence theorem of almost periodic solution for general functional differential equations, introducing many real parameters and applying the Lyapunov functional method and the technique of Young inequality, we obtain some sufficient conditions to ensure the existence, uniqueness, and global exponential stability of almost periodic solution. The results obtained in this paper are new, useful, and extend and improve the existing ones in previous literature.

  12. 41 CFR 302-2.10 - Does the 1-year time period in § 302-2.8 include time that I cannot travel and/or transport my...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 41 Public Contracts and Property Management 4 2014-07-01 2014-07-01 false Does the 1-year time period in § 302-2.8 include time that I cannot travel and/or transport my household effects due to... time that I cannot travel and/or transport my household effects due to shipping restrictions to or...

  13. 41 CFR 302-2.10 - Does the 2-year time period in § 302-2.8 include time that I cannot travel and/or transport my...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 41 Public Contracts and Property Management 4 2011-07-01 2011-07-01 false Does the 2-year time period in § 302-2.8 include time that I cannot travel and/or transport my household effects due to... time that I cannot travel and/or transport my household effects due to shipping restrictions to or...

  14. 41 CFR 302-2.10 - Does the 2-year time period in § 302-2.8 include time that I cannot travel and/or transport my...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 4 2010-07-01 2010-07-01 false Does the 2-year time period in § 302-2.8 include time that I cannot travel and/or transport my household effects due to... time that I cannot travel and/or transport my household effects due to shipping restrictions to or...

  15. 41 CFR 302-2.10 - Does the 1-year time period in § 302-2.8 include time that I cannot travel and/or transport my...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 41 Public Contracts and Property Management 4 2013-07-01 2012-07-01 true Does the 1-year time period in § 302-2.8 include time that I cannot travel and/or transport my household effects due to... time that I cannot travel and/or transport my household effects due to shipping restrictions to or...

  16. 41 CFR 302-2.10 - Does the 1-year time period in § 302-2.8 include time that I cannot travel and/or transport my...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 4 2012-07-01 2012-07-01 false Does the 1-year time period in § 302-2.8 include time that I cannot travel and/or transport my household effects due to... time that I cannot travel and/or transport my household effects due to shipping restrictions to or...

  17. The effect of temperature and extraction period of time on the chemicals content of emprit ginger ethanol extract (Zingiber officinale var. Rubrum)

    NASA Astrophysics Data System (ADS)

    Ratnaningrum, Diah; Endah, Een Sri; Pudjiraharti, Sri

    2017-01-01

    Research on extraction method of emprit ginger using ethanol with agitation of 100 rpm at different temperatures (ambient temperature, 40, and 50°C) and various extraction period of times (30, 60, and 90 minutes) was conducted. Analysis of chemicals content i.e. total phenolic and total flavonoid. The objective of this work was to study the effect of temperatures and extraction period of times on the chemicals content of its ethanol extract. Based on the results of the test, the highest content total flavonoid (5.17% w/w) was resulted at 40°C for 90 minutes, while the total phenolic content was not affected by either temperature or extraction period of times used. The content of total phenolic was around 2.39% to 2.65% w/w.

  18. Earthquake Sequences Identification, from Analysis of Earthquake Occurrence Time Series Considering Multiple Semi-Periodic Sequences and Extraneous Events. Parkfield et al

    NASA Astrophysics Data System (ADS)

    Nava Pichardo, F. A.; Quinteros, C. B.; Glowacka, E.; Frez, J.

    2013-05-01

    We present a new method, based on the analytic Fourier transform, to identify semi-periodic sequences in regional large earthquake occurrence times series, which allows for the presence of multiple semi-periodic sequences and/or events not belonging to any identifiable sequence in the time series. The method yields estimates of the departure from periodicity of an observed sequence, and of the probability that the sequence is not due to chance. These estimates are used to make and to evaluate forecasts of future events belonging to each sequence. The method is surprisingly capable of correctly identifying sequences, unidentifiable by eye, in complicated time series. An example of application of the method to real seismicity data is analysis of the Parkfield event series, which correctly aftcasts the September 2004 earthquake. Other examples of sequence identification in earthquakes from central Japan and Venezuela are also shown.

  19. Central southern Africa at the time of the African Humid Period: A new analysis of Holocene palaeoenvironmental and palaeoclimate data.

    NASA Astrophysics Data System (ADS)

    Burrough, Sallie; Thomas, David

    2014-05-01

    The Holocene African Humid Period (c 14.8-5.5 ka) is now recognised in high-resolution records from western Africa as well as in tropical Africa north of the equator. Establishing a clear picture of Holocene environmental changes from palaeodata in central southern Africa is, however, proving both difficult and contentious. This is because in dryland systems in particular it can be difficult to distinguish the effects of sub-millennial scale regional climatic variability from those of major externally-forced global climate changes. We analyse and review existing records for central southern Africa, and neighbouring areas affected by the same climate systems, to attempt to build a clearer spatial picture of regional hydrological system responses during the Holocene. We suggest palaeodata, including new data from Makgadikgadi basin barchan dunes indicate mid-late Holocene aridity following a period of marked hydrological dynamism extending from the early Holocene. We propose that present-day conditions in central southern Africa are relatively stable compared to the early and mid-Holocene and infer that this period of relative stability in the landscape has occurred since ca. 2 ka. We explain Holocene hydrological changes through analysis of changing zonal climatic influences linked to Congo Air Boundary (CAB) and Intertropical Convergence Zone (ITCZ) dynamics, the effects of which filter into the region via complex drainage basin dynamics. It is proposed that, sensu stricto, the AHP was not a spatially uniform feature of early Holocene central southern Africa.

  20. Paternal psychosocial characteristics and corporal punishment of their 3-year-old children.

    PubMed

    Lee, Shawna J; Perron, Brian E; Taylor, Catherine A; Guterman, Neil B

    2011-01-01

    This study uses data from 2,309 biological fathers who participated in the Fragile Families and Child Well-Being Study (FFCWS) to examine associations between psychosocial characteristics and levels of corporal punishment (CP) toward their 3-year-old children over the past month. Results indicate that 61% of the fathers reported no CP over the past month, 23% reported using CP once or twice, and 16% reported using CP a few times in the past month or more. In multivariate models controlling for important sociodemographic factors as well as characteristics of the child, fathers' parenting stress, major depression, heavy alcohol use, and drug use were significantly associated with greater use of CP, whereas involvement with the child and generalized anxiety disorder were not. Girls were less likely to be the recipient of CP than were boys, and child externalizing behavior problems but not internalizing behavior problems were associated with more CP.

  1. Modular stem fixed-bearing total ankle replacement: prospective results of 23 consecutive cases with 3-year follow-up.

    PubMed

    Brigido, Stephen A; Galli, Melissa M; Bleazey, Scott T; Protzman, Nicole M

    2014-01-01

    In the present report, the 3-year outcomes of 23 consecutive patients treated with a modular stem fixed-bearing total ankle replacement are described. Pain, functional impairment, and disability were assessed annually using a visual analog scale. Complications and additional procedures also were recorded. Compared with preoperative pain (8.4 ± 1.4), functional impairment (8.7 ± 2.3), and disability (3.0 ± 2.5), there were statistically significant postoperative improvements at 1 year (pain, 2.6 ± 1.6; functional impairment, 3.1 ± 2.1; disability, 0.9 ± 1.2), 2 years (pain, 1.5 ± 1.3; functional impairment, 1.9 ± 1.4; disability, 0.6 ± 1.4), and 3 years (pain, 1.3 ± 1.3; functional impairment, 1.9 ± 1.9; disability, 0.4 ± 0.9; p ≤ .001). Pain, function, and disability significantly improved postoperatively from 1 to 2 years (p ≤ .008) and from 1 to 3 years (p ≤ .008). The reductions in pain, functional impairment, and disability were maintained from 2 to 3 years (p ≥ .08). Nine complications (39.1%) were encountered: 1 deep infection, 2 pulmonary embolisms, 3 wounds, 1 ectopic bone formation, 1 stiff joint, and 1 talar subsidence. In the 3-year follow-up period, 3 patients (13.0%) required additional procedures after the immediate postoperative phase. Our results have demonstrated that modular stem fixed-bearing prostheses can be implanted in a predictable and consistent fashion with resultant improvements in pain, function, and disability. Future studies evaluating the clinical outcomes after modular stem fixed-bearing total ankle replacement are warranted.

  2. Climatic and human impacts on quasi-periodic and abrupt changes of sedimentation rate at multiple time scales in Lake Taihu, China

    NASA Astrophysics Data System (ADS)

    Liu, Huiyu; Xu, Xiaojuan; Lin, Zhenshan; Zhang, Mingyang; Mi, Ying; Huang, Changchun; Yang, Hao

    2016-12-01

    With the ensemble Empirical Mode Decomposition Method (EEMD) and the non-parametric Mann-Kendall Test, the quasi-periodic and abrupt changes of sedimentation rate at multiple time scales, and their relations to climate changes and human activities from 1951 to 2010 in Meiliang Bay of Lake Taihu (China) were studied. The results showed the following. (1) The change in sedimentation rate can be completely decomposed into three quasi-periodic changes on 3.7, 6.4, and 24-yr time scales, and a long-term trend. (2) The quasi-periodic changes in sedimentation rate are significantly and positively related to changes in annual average temperature at 6.4 and 24-yr time scales and human activities at 3.7-yr time scales, and not significantly related to precipitation at these time scales. The trend of sedimentation rate has a negative relation with temperature, but positive relations with precipitation and human activities. As a whole, the total variance contribution of climate changes to the quasi-periodic changes of sedimentation rate is close to that of human activities; (3) Temperature and precipitation are possibly related to the abrupt change of sedimentation rate as a whole. Floods have significant impacts on abrupt changes in the sedimentation rate at 3.7, 6.4 and 24-yr time scales. Moreover, some abrupt changes of sedimentation rate at 3.7- and 6.4-yr time scales are partly related to the changes of precipitation at 3.1-yr time scale and temperature at 5-yr time scale. The results of this study will help identify the impacts of climate change and human activities on lake sedimentation at different time scales, and will be available for use as a guide for reasonable development and effective protection of lake resources.

  3. Stable time patterns of railway suicides in Germany: comparative analysis of 7,187 cases across two observation periods (1995–1998; 2005–2008)

    PubMed Central

    2014-01-01

    Background The majority of fatalities on the European Union (EU) railways are suicides, representing about 60% of all railway fatalities. The aim of this study was to compare time patterns of suicidal behaviour on railway tracks in Germany between two observation periods (1995–1998 and 2005–2008) in order to investigate their stability and value in railway suicide prevention. Methods Cases were derived from the National Central Registry of person accidents on the German railway network (STABAG). The association of daytime, weekday and month with the mean number of suicides was analysed applying linear regression. Potential differences by observation period were assessed by adding observation period and the respective interaction terms into the linear regression. A 95% confidence interval for the mean number of suicides was computed using the t distribution. Results A total of 7,187 railway suicides were recorded within both periods: 4,102 (57%) in the first period (1995–1998) and 3,085 (43%) in the second (2005–2008). The number of railway suicides was highest on Mondays and Tuesdays in the first period with an average of 3.2 and 3.5 events and of 2.6 events on both days in the second period. In both periods, railway suicides were more common between 6:00 am and noon, and between 6:00 pm and midnight. Seasonality was only prominent in the period 1995–1998. Conclusions Over the course of two observation periods, the weekday and circadian patterns of railway suicides remained stable. Therefore, these patterns should be an integral part of railway suicide preventive measures, e.g. gatekeeper training courses. PMID:24498876

  4. Wavelet Analysis of the Periodicity and Correlation of the 420-ka Temperature, Carbon Dioxide, and Methane Time Series from the Vostok Ice Core

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Huang, S.

    2010-12-01

    A good understanding of the history of Earth’s surface temperature and the excursion of atmospheric greenhouse gas composition is of crucial importance in reasoning the course and causes of climate change. However, identifying the variation and correspondence of different climate variables has been a challenging task due to the noisy, complex, and non-linear nature of paleoclimate records. Here we use wavelet technique to revisit the 420-ka temperature, carbon dioxide, and methane records from the ice core of Vostok station in East Antarctica [Petit et al., 1999, Nature, 399, 429] for the periodicity of and the correlation among these three variables. As with many other paleoclimate records, the sampling intervals of the Vostok records are different from variable to variable and from time to time. To allow for the application of continuous Morlet wavelet transform, cross-wavelet transform, and cross-wavelet coherence techniques, all three records were interpolated into 500-year equal interval time series with a cubic polynomial interpolation scheme. All three time series demonstrate the orbital eccentricity oscillation of about 100-ka as the most significant period with a lengthening trend towards the present day. Another periodicity common to all three records is the orbital tilt period of about 41 ka. However, the about 21 ka precession period can only be identified in the methane time series in the Morlet wavelet power spectrum. Our analysis further shows that temperature, CO2, and CH4 are well correlated, whereas the linkage of temperature with CO2 is stranger than that of temperature with CH4 and CO2 with CH4. In pairwise cross-wavelet transform and cross-wavelet coherence diagrams, almost all significant sections show in-phase correlations. Generally, the fluctuations of CO2 and CH4 appear to be either in sync with or slightly led by temperature variation, although there are isolated slots of millennium scales when the temperature - greenhouse gas

  5. Toxicological findings in cases of alleged drug-facilitated sexual assault in the United Kingdom over a 3-year period.

    PubMed

    Scott-Ham, Michael; Burton, Fiona C

    2005-08-01

    This paper outlines the toxicology results from 1014 cases of claimed drug-facilitated sexual assault (DFSA) analysed at the Forensic Science Service, London Laboratory between January 2000 and December 2002. Where appropriate, either a whole blood sample and/or a urine sample was analysed for alcohol, common drugs of abuse and potentially stupefying drugs. The results were interpreted with respect to the number of drugs detected and an attempt was made to distinguish between voluntary and involuntary ingestion from information supplied. Alcohol (either alone or with an illicit and/or medicinal drug) was detected in 470 of all cases (46%). Illicit drugs were detected in 344 cases (34%), with cannabis being the most commonly detected (26% of cases), followed by cocaine (11%). In 21 cases (2%), a sedative or disinhibiting drug was detected which had not been admitted and could therefore be an instance of deliberate spiking. This included three cases in which complainants were allegedly given Ecstasy (MDMA) without their knowledge. Other drugs detected included gammahydroxybutyrate (GHB) and the benzodiazepine drugs diazepam and temazepam. Another nine cases (1%) involved the complainant being either given or forced to ingest pharmaceutical tablets or an illicit drug.

  6. Central southern Africa at the time of the African Humid Period: a new analysis of Holocene palaeoenvironmental and palaeoclimate data

    NASA Astrophysics Data System (ADS)

    Burrough, S. L.; Thomas, D. S. G.

    2013-11-01

    The Holocene African Humid Period (c 14.8-5.5 ka) is now recognised in high-resolution records from western Africa as well as in tropical Africa north of the equator. Establishing a clear picture of Late Quaternary, including Holocene, environmental changes in central southern Africa is proving both difficult and contentious. This is because in dryland systems in particular it can be difficult to distinguish the effects of sub-millennial scale regional climatic variability from those of major externally-forced global climate changes, and because it is essential to distinguish records of environmental drivers from those of environmental responses. We analyse and review existing records for central southern Africa, and neighbouring areas affected by the same climate systems, to understand the primary controls of regional hydrological systems during the Holocene. We then present new data from Makgadikgadi basin barchan dunes that indicate mid-late Holocene aridity following a period of marked hydrological dynamism extending from the early Holocene. We suggest that present-day conditions in central southern Africa are relatively stable compared to the early and mid-Holocene and infer that this period of relative stability in the landscape has occurred since ca 2 ka. We explain Holocene hydrological changes through analysis of changing zonal climatic influences linked to Congo Air Boundary (CAB) and Intertropical Convergence Zone (ITCZ) dynamics, the effects of which filter into the region via complex drainage basin dynamics. It is proposed that, sensu stricto, the AHP was not a spatially uniform feature of early Holocene central southern Africa.

  7. Time-domain analysis of bandgap characteristics of two-dimensional periodic structures by use of a source-model technique.

    PubMed

    Ludwig, Alon; Leviatan, Yehuda

    2008-02-01

    We introduce a time-domain source-model technique for analysis of two-dimensional, transverse-magnetic, plane-wave scattering by a photonic crystal slab composed of a finite number of identical layers, each comprising a linear periodic array of dielectric cylinders. The proposed technique takes advantage of the periodicity of the slab by solving the problem within a unit cell of the periodic structure. A spectral analysis of the temporal behavior of the fields scattered by the slab shows a clear agreement between frequency bands where the spectral density of the transmitted energy is low and the bandgaps of the corresponding two-dimensionally infinite periodic structure. The effect of the bandwidth of the incident pulse and its center frequency on the manner it is transmitted through and reflected by the slab is studied via numerical examples.

  8. Existence, uniqueness and regularity of a time-periodic probability density distribution arising in a sedimentation-diffusion problem

    NASA Technical Reports Server (NTRS)

    Nitsche, Ludwig C.; Nitsche, Johannes M.; Brenner, Howard

    1988-01-01

    The sedimentation and diffusion of a nonneutrally buoyant Brownian particle in vertical fluid-filled cylinder of finite length which is instantaneously inverted at regular intervals are investigated analytically. A one-dimensional convective-diffusive equation is derived to describe the temporal and spatial evolution of the probability density; a periodicity condition is formulated; the applicability of Fredholm theory is established; and the parameter-space regions are determined within which the existence and uniqueness of solutions are guaranteed. Numerical results for sample problems are presented graphically and briefly characterized.

  9. Extent of mismatch between the period of circadian clocks and light/dark cycles determines time-to-emergence in fruit flies.

    PubMed

    Yadav, Pankaj; Choudhury, Deepak; Sadanandappa, Madhumala K; Sharma, Vijay Kumar

    2015-08-01

    Circadian clocks time developmental stages of fruit flies Drosophila melanogaster, while light/dark (LD) cycles delimit emergence of adults, conceding only during the "allowed gate." Previous studies have revealed that time-to-emergence can be altered by mutations in the core clock gene period (per), or by altering the length of LD cycles. Since this evidence came from studies on genetically manipulated flies, or on flies maintained under LD cycles with limited range of periods, inferences that can be drawn are limited. Moreover, the extent of shortening or lengthening of time-to-emergence remains yet unknown. In order to pursue this further, we assayed time-to-emergence of D. melanogaster under 12 different LD cycles as well as in constant light (LL) and constant dark conditions (DD). Time-to-emergence in flies occurred earlier under LL than in LD cycles and DD. Among the LD cycles, time-to-emergence occurred earlier under T4-T8, followed by T36-T48, and then T12-T32, suggesting that egg-to-emergence duration in flies becomes shorter when the length of LD cycles deviates from 24 h, bearing a strong positive and a marginally negative correlation with day length, for values shorter and longer than 24 h, respectively. These results suggest that the extent of mismatch between the period of circadian clocks and environmental cycles determines the time-to-emergence in Drosophila.

  10. Enhancement of temporal coherence via time-periodic coupling strength in a scale-free network of stochastic Hodgkin-Huxley neurons

    NASA Astrophysics Data System (ADS)

    Yilmaz, Ergin; Baysal, Veli; Ozer, Mahmut

    2015-08-01

    We investigate the effects of time-periodic coupling strength on the temporal coherence or firing regularity of a scale-free network consisting of stochastic Hodgkin-Huxley (H-H) neurons. The temporal coherence exhibits a resonance-like behavior depending on the cell size or the channel noise intensity. The best temporal coherence requires an optimal channel noise intensity, and this coherence can be significantly increased by time-periodic coupling strength when its frequency matches the integer multiples of the intrinsic subthreshold oscillation frequency of H-H neuron. Particularly, we find the multiple-coherence resonance depending on frequency of time-periodic coupling strength at the optimal noise intensity. We also obtain a resonance-like dependence of temporal coherence on the amplitude of time-periodic coupling strength. Additionally, we investigate the effects of average degree on the temporal coherence and find that the temporal coherence exhibits a resonance-like behavior with respect to the network average degree, indicating that the best regularity requires an optimal average degree.

  11. Some sufficient conditions for stabilizing periodic orbits without the odd-number property by delayed feedback control in continuous-time systems

    NASA Astrophysics Data System (ADS)

    Nakajima, Hiroyuki

    2004-06-01

    One of the important topics in the study of delayed feedback control (DFC) for chaotic systems is stability analysis. In the present Letter, we give some sufficient conditions for stabilizing periodic orbits by the DFC without the odd-number property in continuous-time systems. Our results naturally connect the stability condition for inversely unstable orbits and the odd-number limitation.

  12. 20 CFR 1002.116 - Is the time period for reporting back to an employer extended if the employee is hospitalized for...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Is the time period for reporting back to an employer extended if the employee is hospitalized for, or convalescing from, an illness or injury incurred in, or aggravated during, the performance of service? 1002.116 Section 1002.116 Employees' Benefits OFFICE OF THE ASSISTANT SECRETARY...

  13. Linear stability of a surfactant-laden annular film in a time-periodic pressure-driven flow through a capillary.

    PubMed

    Wei, Hsien-Hung; Halpern, David; Grotberg, James B

    2005-05-15

    This paper analyzes the effect of surfactant on the linear stability of an annular film in a capillary undergoing a time-periodic pressure gradient force. The annular film is thin compared to the radius of the tube. An asymptotic analysis yields a coupled set of equations with time-periodic coefficients for the perturbed fluid-fluid interface and the interfacial surfactant concentration. Wei and Rumschitzki (submitted for publication) previously showed that the interaction between a surfactant and a steady base flow could induce a more severe instability than a stationary base state. The present work demonstrates that time-periodic base flows can modify the features of the steady-flow-based instability, depending on surface tension, surfactant activity, and oscillatory frequency. For an oscillatory base flow (with zero mean), the growth rate decreases monotonically as the frequency increases. In the low-frequency limit, the growth rate approaches a maximum corresponding to the growth rate of a steady base flow having the same amplitude. In the high-frequency limit, the growth rate reaches a minimum corresponding to the growth rate in the limit of a stationary base state. The underlying mechanisms are explained in detail, and extension to other time-periodic forms is further exploited.

  14. Solar EUV Variability from FISM and SDO/EVE During Solar Minimum, Active, and Flaring Time Periods

    NASA Technical Reports Server (NTRS)

    Chamberlin, Phillip C.

    2011-01-01

    The Living With a Star (LWS) Focus Science Team has identified three periods of different solar activity levels for which they will be determining the Earth's Ionosphere and Thermosphere response. Not only will the team be comparing individual models (e.g. FLIP, T1MEGCM, GLOW) outcome driven by the various levels of solar activity, but the models themselves will also be compared. These models all rely on the input solar EUV (0.1 -190 nm) irradiance to drive the variability. The Flare Irradiance Spectral Model (FISM) and the EUV Variability Experiment (EVE) onboard provide the Solar Dynamics Observatory (SDO) provide the most accurate quantification of these irradiances. Presented and discussed are how much the solar EUV irradiance changes during these three scenarios, both as a function of activity and wavelength.

  15. Environmental controls on fungal community composition and abundance over 3 years in native and degraded shrublands.

    PubMed

    Glinka, Clare; Hawkes, Christine V

    2014-11-01

    Soil fungal communities have high local diversity and turnover, but the relative contribution of environmental and regional drivers to those patterns remains poorly understood. Local factors that contribute to fungal diversity include soil properties and the plant community, but there is also evidence for regional dispersal limitation in some fungal communities. We used different plant communities with different soil conditions and experimental manipulations of both vegetation and dispersal to distinguish among these factors. Specifically, we compared native shrublands with former native shrublands that had been disturbed or converted to pasture, resulting in soils progressively more enriched in carbon and nutrients. We tested the role of vegetation via active removal, and we manipulated dispersal by adding living soil inoculum from undisturbed native sites. Soil fungi were tracked for 3 years, with samples taken at ten time points from June 2006 to June 2009. We found that soil fungal abundance, richness, and community composition responded primarily to soil properties, which in this case were a legacy of plant community degradation. In contrast, dispersal had no effect on soil fungi. Temporal variation in soil fungi was partly related to drought status, yet it was much broader in native sites compared to pastures, suggesting some buffering due to the increased soil resources in the pasture sites. The persistence of soil fungal communities over 3 years in this study suggests that soil properties can act as a strong local environmental filter. Largely persistent soil fungal communities also indicate the potential for strong biotic resistance and soil legacies, which presents a challenge for both the prediction of how fungi respond to environmental change and our ability to manipulate fungi in efforts such as ecosystem restoration.

  16. Iron Status and Febrile Seizure- A Case Control Study in Children Less Than 3 Years

    PubMed Central

    SADEGHZADEH, Mansour; KHOSHNEVIS ASL, Parisa; MAHBOUBI, Esrafil

    2012-01-01

    Objective Febrile seizure is one of the most common neurological conditions of childhood. Several theories, such as iron deficiency anemia have been proposed as the pathogenesis of this condition. The aim of this study was to find the association between iron deficiency anemia and febrile seizures in children aged 6 months to 3 years admitted in Valie Asr hospital in Zanjan. Materials &Methods Hemoglobin (Hb), mean corpuscular volume (MCV), serum iron (SI), total iron binding capacity (TIBC) and SI/TIBC ratio were assessed in one hundred children with febrile seizures and compared to the values of one hundred healthy children presenting in a heath care center in the same period as the control group. Results A total of 6% of cases had iron deficiency anemia which was similar to the control group. In the case group SI/TIBC ratio below 12% was seen in 58% of children which was significantly higher than that of the control group (29%). Conclusion The results of this study suggest that although anemia was not common among febrile seizure patients, iron deficiency was more frequent in these patients. PMID:24665277

  17. Periodic protein adsorption at the gold/biotin aqueous solution interface: evidence of kinetics with time delay

    PubMed Central

    Neff, H.; Laborde, H. M.; Lima, A. M. N.

    2016-01-01

    An oscillatory molecular adsorption pattern of the protein neutravidin from aqueous solution onto gold, in presence of a pre-deposited self assembled mono-molecular biotin film, is reported. Real time surface Plasmon resonance sensing was utilized for evaluation of the adsorption kinetics. Two different fractions were identified: in the initial phase, protein molecules attach irreversibly onto the Biotin ligands beneath towards the jamming limit, forming a neutravidin-biotin fraction. Afterwards, the growth rate exhibits distinct, albeit damped adsorption-desorption oscillations over an extended time span, assigned to a quasi reversibly bound fraction. These findings agree with, and firstly confirm a previously published model, proposing macro-molecular adsorption with time delay. The non-linear dynamic model is applicable to and also resembles non-damped oscillatory binding features of the hetero-catalytic oxidation of carbon monoxide molecules on platinum in the gas phase. An associated surface residence time can be linked to the dynamics and time scale required for self-organization. PMID:27808155

  18. Periodic protein adsorption at the gold/biotin aqueous solution interface: evidence of kinetics with time delay

    NASA Astrophysics Data System (ADS)

    Neff, H.; Laborde, H. M.; Lima, A. M. N.

    2016-11-01

    An oscillatory molecular adsorption pattern of the protein neutravidin from aqueous solution onto gold, in presence of a pre-deposited self assembled mono-molecular biotin film, is reported. Real time surface Plasmon resonance sensing was utilized for evaluation of the adsorption kinetics. Two different fractions were identified: in the initial phase, protein molecules attach irreversibly onto the Biotin ligands beneath towards the jamming limit, forming a neutravidin-biotin fraction. Afterwards, the growth rate exhibits distinct, albeit damped adsorption-desorption oscillations over an extended time span, assigned to a quasi reversibly bound fraction. These findings agree with, and firstly confirm a previously published model, proposing macro-molecular adsorption with time delay. The non-linear dynamic model is applicable to and also resembles non-damped oscillatory binding features of the hetero-catalytic oxidation of carbon monoxide molecules on platinum in the gas phase. An associated surface residence time can be linked to the dynamics and time scale required for self-organization.

  19. Differences in Nighttime and Daytime Ambulatory Blood Pressure When Diurnal Periods Are Defined by Self-report, Fixed-Times and Actigraphy: Improving the Detection of Hypertension Study

    PubMed Central

    BOOTH, John N.; MUNTNER, Paul; ABDALLA, Marwah; DIAZ, Keith M.; VIERA, Anthony J.; REYNOLDS, Kristi; SCHWARTZ, Joseph E.; SHIMBO, Daichi

    2016-01-01

    Objectives To determine whether defining diurnal periods by self-report, fixed-time or actigraphy produce different estimates of nighttime and daytime ambulatory blood pressure (ABP). Methods Over a median of 28 days, 330 participants completed two 24-hour ABP and actigraphy monitoring periods with sleep diaries. Fixed nighttime and daytime periods were defined as 00:00–06:00 and 10:00–20:00, respectively. Using the first ABP period, within-individual differences for mean nighttime and daytime ABP and Kappa statistics for nighttime and daytime hypertension (systolic/diastolic ABP ≥120/70 mmHg and ≥135/85 mmHg, respectively) were estimated comparing self-report, fixed-time or actigraphy for defining diurnal periods. Reproducibility of ABP was also estimated. Results Within-individual mean differences in nighttime systolic ABP were small, suggesting little bias, when comparing the three approaches used to define diurnal periods. The distribution of differences, represented by 95% confidence intervals (CI), in nighttime systolic and diastolic ABP and daytime systolic and diastolic ABP was narrowest for self-report versus actigraphy. For example, mean differences (95% CI) in nighttime systolic ABP for self-report versus fixed-time was −0.53 (−6.61,+5.56) mmHg, self-report versus actigraphy was 0.91 (−3.61,+5.43) mmHg and fixed-time versus actigraphy was 1.43 (−5.59,+8.46) mmHg. Agreement for nighttime and daytime hypertension was highest for self-report versus actigraphy: Kappa statistic (95% CI)=0.91 (0.86,0.96) and 1.00 (0.98,1.00), respectively. The reproducibility of mean ABP and hypertension categories was similar using each approach. Conclusion Given the high agreement with actigraphy, these data support using self-report to define diurnal periods on ABP monitoring. Further, the use of fixed-time periods may be a reasonable alternative approach. PMID:26867054

  20. Multidisciplinary Approach to Determine the Optimal Time and Period for Extracting the Essential Oil from Mentha suaveolens Ehrh.

    PubMed

    Garzoli, Stefania; Pirolli, Adele; Vavala, Elisabetta; Di Sotto, Antonella; Sartorelli, Gianni; Božović, Mijat; Angiolella, Letizia; Mazzanti, Gabriela; Pepi, Federico; Ragno, Rino

    2015-05-26

    A comprehensive study on essential oils (EOs) extracted from some Mentha suaveolens L. samples, collected in the countryside of Tarquinia, is reported. In this study, the procedure for essential oil preparation, in terms of harvesting and extraction time, was analyzed in detail for the first time. The GC/MS analysis, carried out on 18 samples, revealed that piperitenone oxide (PO), the main essential oils' chemical constituent, is primarily responsible for the related antifungal activity. Nevertheless, EOs with lower PO content indicate that other chemicals, such as para-cymenene, may participate in exerting the EOs' antifungal effect. Furthermore, the bacterial reverse mutation assay highlighted lack of mutagenic effect in all tested samples. Analysis of the results indicated that for higher activity, the essential oils should be produced with 3 h maximum hydrodistillation, regardless of the harvesting time. Differently, the maximum essential oil yield can be obtained in August and the highest piperitenone oxide percentage is obtainable in July.