Kusin, F M; Jarvis, A P; Gandy, C J
2010-01-01
Analysis of residence time distribution (RTD) has been conducted for the UK Coal Authority's mine water treatment wetland at Lambley, Northumberland, to determine the hydraulic performance of the wetland over a period of approximately 4 years since site commissioning. The wetland RTD was evaluated in accordance with moment analysis and modelled based on a tanks-in-series (TIS) model to yield the hydraulic characteristics of system performance. Greater hydraulic performance was seen during the second site monitoring after 21 months of site operation i.e. longer hydraulic residence time to reflect overall system hydraulic efficiency, compared to wetland performance during its early operation. Further monitoring of residence time during the third year of wetland operation indicated a slight reduction in hydraulic residence time, thus a lower system hydraulic efficiency. In contrast, performance during the fourth year of wetland operation exhibited an improved overall system hydraulic efficiency, suggesting the influence of reed growth over the lifetime of such systems on hydraulic performance. Interestingly, the same pattern was found for iron (which is the primary pollutant of concern in ferruginous mine waters) removal efficiency of the wetland system from the second to fourth year of wetland operation. This may therefore, reflect the maturity of reeds for maintaining efficient flow distribution across the wetland to retain a longer residence time and significant fractions of water involved to enhance the extent of treatment received for iron attenuation. Further monitoring will be conducted to establish whether such performance is maintained, or whether efficiency decreases over time due to accumulation of dead plant material within the wetland cells. PMID:20962411
Garcell, Humberto Guanche; Arias, Ariadna Villanueva; Fernandez, Eliezer Alemán; Guerrero, Yaquelín Batista; Serrano, Ramon N. Alfonso
2016-01-01
Objectives We sought to evaluate the trend of antibiotic consumption in patients admitted to a community hospital in Qatar with an antimicrobial stewardship program. Methods This observational study was carried out in a 75-bed facility in Western Qatar over a 4-year period (2012–2015). The monitoring of antimicrobial consumption from inpatient wards was performed from the pharmacy records and presented as defined daily dose (DDD) divided by the patient days and expressed as 100 bed-days (DBD). Results The consumption of antimicrobials in 2012 was 171.3 DBD, and increased to 252.7 DBD in 2013, 229.1 DBD in 2014, and 184.7 DBD in 2015. Cephalosporins use reduced from 98.2 DBD in 2013 to 51.5 DBD in 2015 while the consumption of penicillins increased during the beginning of 2014 with a slight decrease in 2015. Carbapenems consumption during 2014–2015 was lower than previous years, and vice-versa for aminoglycosides. Fluoroquinolones had a sustained increase with 37.1% increased consumption in 2015 compared to the two previous years. There was an increase in the use of intravenous (IV) (108.5%) and oral azithromycin (55.1%) and the use of oral (152.8%) and IV moxifloxacin (22.9%). Conclusions We observed a decrease in antibiotic use in patients admitted to a community hospital with an antimicrobial stewardship program, but the increase in fluoroquinolones consumption is a concern that requires focused strategies. PMID:27602189
The Maudsley Early Onset Schizophrenia Study: Cognitive Function Over a 4-Year Follow-Up Period
Frangou, Sophia; Hadjulis, Michael; Vourdas, Apostolos
2008-01-01
Generalized cognitive deficits have been consistently reported in adolescents with early onset schizophrenia (EOS; defined as onset before the age of 17 years). The impact on cognition of potential interactions between disease pathology and brain maturation remains unclear. We therefore compared cognitive function between 20 EOS patients and 20 healthy controls matched on age, gender, and parental socioeconomic status at 2 time points, when aged 15.58 (2.27) and after a mean interval of 4 ± 1.08 years when aged 19.46 (2.21) years. Repeated measures analyses revealed no differences between patients and controls in the degree of change over this time period in general intellectual function and planning ability as measured by the Tower of London. There was deterioration in the verbal memory and attentional control index scores from the Wechsler Memory Scale-Revised but relative improvement in Part A of the Trail Making Test. Patients’ level of symptomatology as well as the type and dose of medication were comparable at both time points. We conclude that most aspects of cognitive function remain relatively stable in EOS patients during adolescence; there is evidence for deterioration in immediate verbal memory and attention while speed of information processing may show improvement. PMID:18024468
A measure of inspection time in 4-year-old children: the Benny Bee IT task.
Williams, Sarah E; Turley, Christopher; Nettelbeck, Ted; Burns, Nicholas R
2009-09-01
Inspection time (IT) measures speed of information processing without the confounding influence of motor speed. While IT has been found to relate to cognitive abilities in adults and older children, no measure of IT has been validated for use with children younger than 6 years. This study examined the validity of a new measure of IT for preschool children. N = 71 4-year-old children completed the new IT task and standardized measures of fluid ability, visuospatial ability, and speed of processing. N = 50 adults completed the same tasks and, additionally, a standard IT task. Results showed that the new IT task is a stable, reliable measure of IT in 4-year-old children. The new task had reasonable concurrent validity with the standard IT task in adults and the relationships between cognitive abilities, particularly general cognitive ability, and IT are sufficiently similar in young children and adults to suggest that the new IT task may be a useful tool for research in populations where IT was previously not measurable. PMID:19994574
Transfer and Graduation Rates, Full-Time Entrants after 4 Years. Revised Brief RB93-16.
ERIC Educational Resources Information Center
Clagett, Craig A.
Drawing from annual data provided by the Maryland Higher Education Commission, Prince George's Community College (PGCC) in Maryland conducted a study of the status of first-time, full-time students at PGCC 4 years after entry. In particular, the study examined the number and percentages of students earning certificates and associate degrees and/or…
NASA Astrophysics Data System (ADS)
Hoffmann, Mathias; Albiac Borraz, Elisa; Garcia Alba, Juana; Augustin, Jürgen; Sommer, Michael
2015-04-01
Agriculture in the hummocky ground moraine landscape of NE-Germany is characterized by an increase in energy crop cultivation, like maize or sorghum. Both enhance lateral C fluxes by erosion and induce feedbacks on C dynamics of agroecosystems as a result of reduced wintertime plant cover and vigorous crop growth during summer. However, the actual impact of these phenomena on the CO2-sink/-source function of agricultural landscapes, is still not clear. Therefore, the interdisciplinary project "CarboZALF" was established in Dedelow/Prenzlau (NE-Germany) in 2009. Within the field experiment CarboZALF-D, CO2 fluxes for the soil-plant systems were monitored, covering typical landscape relevant soil states in respect to erosion and deposition, like Calcic Cutanic Luvisol and Endogleyic Colluvic Regosol. Automated chamber systems, each consisting of four transparent chambers (2.5 m height, basal area 2.25 m2), were placed along gradients at both measurement sites. Monitored CO2 fluxes were gap-filled on a high-temporal resolution by modelling ecosystem respiration (Reco), gross primary productivity (GPP) and net ecosystem exchange (NEE) based on parallel and continuous measurements of the CO2 exchange, soil and air temperatures as well as photosynthetic active radiation (PAR). Gap-filling was e.g. needed in case of chamber malfunctions and abrupt disturbances by farming practice. The monitored crop rotation was corn-winter wheat (2 a), sorghum-winter triticale and alfalfa (1.5 a). In our presentation we would like to show insights from a 4 years observation period, with prounounced differences between the eroded and the colluvial soil: The Endogleyic Colluvic Regosol showed higher flux rates for Reco, GPP and NEE compared to the Calcic Cutanic Luvisol. Site-specific NEE and C-balances were positively related to soil C-stocks as well as biomass production, and generated a minor C-sink in case of the Calcic Cutanic Luvisol and a highly variable C-source in case of the
Time Keeping and Working Memory Development in Early Adolescence: A 4-Year Follow-Up
ERIC Educational Resources Information Center
Forman, Helen; Mantyla, Timo; Carelli, Maria G.
2011-01-01
In this longitudinal study, we examined time keeping in relation to working memory (WM) development. School-aged children completed two tasks of WM updating and a time monitoring task in which they indicated the passing of time every 5 min while watching a film. Children completed these tasks first when they were 8 to 12 years old and then 4 years…
A Measure of Inspection Time in 4-Year-Old Children: The Benny Bee IT Task
ERIC Educational Resources Information Center
Williams, Sarah E.; Turley, Christopher; Nettelbeck, Ted; Burns, Nicholas R.
2009-01-01
Inspection time (IT) measures speed of information processing without the confounding influence of motor speed. While IT has been found to relate to cognitive abilities in adults and older children, no measure of IT has been validated for use with children younger than 6 years. This study examined the validity of a new measure of IT for preschool…
Szkody, Paula; Mukadam, Anjum S.; Gaensicke, Boris T. E-mail: mukadam@astro.washington.edu; and others
2012-07-10
Since the large amplitude 2007 outburst which heated its accreting, pulsating white dwarf, the dwarf nova system GW Librae has been cooling to its quiescent temperature. Our Hubble Space Telescope ultraviolet spectra combined with ground-based optical coverage during the third and fourth year after outburst show that the fluxes and temperatures are still higher than quiescence (T = 19,700 K and 17,300 K versus 16,000 K pre-outburst for a log g = 8.7 and d = 100 pc). The K{sub wd} of 7.6 {+-} 0.8 km s{sup -1} determined from the C I {lambda}1463 absorption line, as well as the gravitational redshift implies a white dwarf mass of 0.79 {+-} 0.08 M{sub Sun }. The widths of the UV lines imply a white dwarf rotation velocity v sin i of 40 km s{sup -1} and a spin period of 209 s (for an inclination of 11 deg and a white dwarf radius of 7 Multiplication-Sign 10{sup 8} cm). Light curves produced from the UV spectra in both years show a prominent multiplet near 290 s, with higher amplitude in the UV compared to the optical, and increased amplitude in 2011 versus 2010. As the presence of this set of periods is intermittent in the optical on weekly timescales, it is unclear how this relates to the non-radial pulsations evident during quiescence.
The Change of Grip Strength in a Patient with Congenital Myotonic Dystrophy Over a 4-year Period
Kozuka, Naoki; Uchida, Eiji; Ninomiya, Takafumi; Tatsumi, Haruyuki; Takeda, Hidekatsu; Tachi, Nobutada
2008-01-01
Myotonic dystrophy (MyD) is a neuromuscular disease that is autosomal dominant and the most common form of muscular dystrophy affecting adults. The clinical features of MyD include a multisystemic disorder characterized by myotonia, progressive muscle weakness and wasting, cataracts, premature balding and mental retardation. The most severe type of MyD is classified as congenital MyD (CMyD). The muscle weakness in CMyD is very severe, but muscle development can be observed in the period of growth. However, no clinical case of this type has been reported yet. Therefore, we report on a girl with CMyD who had an increase in muscle strength over a four-year period. The girl with CMyD participated in this study from the age of 9 to the age of 12. The measurement of muscle strength was recorded as the maximum score of grip strength with the use of dynamometers. Grip strength was assessed once a year by the same two physical therapists. Grip strength of CMyD for each year was markedly weak when compared with the normal controls, but muscle strength changed within some specific growth areas. The muscle weakness in CMyD was remarkable, but the result showed that specific muscle strength of CMyD in childhood was actually increased. PMID:25792886
Ribeiro, Rafael Bernardon; Tully, John; Fotiadou, Maria
2015-01-01
There are limited data on women in Medium Secure settings. This study aimed to address this by assessing the characteristics of 45 consecutive admissions to the female ward of a Medium Secure Unit in the United Kingdom over a four-year period. Data on demographics, clinical outcomes and from HONOS-Secure/HONOS and HCR-20 assessments were prospectively collected. Psychiatric diagnoses were recorded using ICD-10 criteria. Data on quality of life from WHO-QoL-BREF surveys were analysed. There was a high proportion of ethnic minorities (57.8%), high rates of childhood and adult abuse and low socioeconomic status. 62.2% of the patients had schizophrenia, 57.8% had multiple diagnoses. The median length of stay at discharge was 465.5 days. There were statistically significant reductions in rates of self-harm and HoNOS-Secure/HoNOS and HCR-20 scores following intervention. Scores on WHO-QoL-BREF compared favourably to a large-scale sample with mental health difficulties. Many characteristics of this sample were comparable to samples from similar populations. However the particularly high proportion of ethnic minorities suggested that the profile of our patients differs from nationwide samples. Intervention by our service was associated with reduced self-harm and improvements in well-defined clinical outcomes and quality of life measures using validated scales. PMID:25748885
Incorporating Spectra Into Periodic Timing
NASA Astrophysics Data System (ADS)
Connors, Alanna; Hong, J.; Protopapas, P.; Kashyap, V.
2011-09-01
The Chandra surveys have resulted in a wealth of data on low-luminosity X-ray sources (Lx 1030-34 erg/s) of Galactic scales beyond the local solar neighborhood. Many of these are compact binaries, in particular, cataclysmic variables, often identified by their periodic X-ray variability and spectra. Hong et al. (2009, 2011) have used energy quantiles (Hong, Schlegel & Grindlay, 2004) as a fast, robust indicator of spectral hardness and absorption of the X-ray sources. Energy quantiles also enable a simple but effective illustration of spectral changes with phase in these periodic systems: e.g. absorption by the accreting material is understood to drive the periodic light-curves. An interesting question is how to best make use of the information encapsulated in the periodic change in energy spectrum, along with the periodic change in intensity, especially for cases of ambiguous period determination? And, how to do it computationally efficiently? A first approach is to do the period search in intensity, as is standard; and then use a criterion of spectral variation to verify possible periods. Huijse, Zegers & Protopapas (2011) recently demonstrated a powerful period estimation technique using information potential and correntropy embedded in the light curve. Similar quantities based on energies (or energy quantiles) of X-ray photons can serve as criteria of spectral variation. A different approach treats the spectrum variations and intensity variations completely independently, searching through period-space in each, and then combining the results. A more general method would include both at the same time, looking for statistically significant variations above what is expected for a constant (in intensity and spectrum).
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....
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....
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....
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....
Christensen, Jan Olav; Knardahl, Stein
2014-07-01
The current study estimated the impact of psychological and social work factors over time on neck pain. A sample of Norwegian employees (n=1250) was surveyed on 3 occasions spanning 4 years. Five exposures were studied: quantitative demands, decision control, social climate, empowering leadership, and role conflict. Group-based trajectory models suggested factors changed little over time-employees could be classified by mean levels of exposure into groups exhibiting stable "high", "middle", and "low" levels. The exception was decision control, for which a 4-level classification was derived: "high", "high-middle", "low-middle", and "low". Pain prevalence at the end of the study period was compared across groups. Risk and prognosis were also assessed separately by dividing the sample according to pain status at baseline. For all factors, distinct differences in risk were observed between exposure groups, controlled for pain at baseline, skill level, sex, and age. Statistically significant effects ranged from 0.38 (CI 0.20-0.73, P<0.01) for high social climate to 3.00 (CI 1.63-5.50, P<0.01) for high role conflict. The risk of new-onset pain was predicted by all factors. ORs ranged from 0.32 (CI 0.16-0.67, P<0.01) for high empowering leadership to 2.61 (CI 1.09-6.21, P<0.05) for high role conflict. Pain persistence was predicted by high role conflict (OR 3.26, CI 1.30-8.18, P<0.05), high quantitative demands (odds ratio [OR] 3.66, CI 1.58-8.49, P<0.01), and high-middle decision control (OR 0.45, CI 0.21-0.99, P<0.05). Future studies should collect information at multiple time points to clarify the impact of prolonged and changing exposure on musculoskeletal pain. PMID:24704365
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...
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...
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...
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...
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...
Darrow, Lyndsey A.; Klein, Mitchel; Flanders, W. Dana; Mulholland, James A.; Tolbert, Paige E.; Strickland, Matthew J.
2014-01-01
Upper and lower respiratory infections are common in early childhood and may be exacerbated by air pollution. We investigated short-term changes in ambient air pollutant concentrations, including speciated particulate matter less than 2.5 μm in diameter (PM2.5), in relation to emergency department (ED) visits for respiratory infections in young children. Daily counts of ED visits for bronchitis and bronchiolitis (n = 80,399), pneumonia (n = 63,359), and upper respiratory infection (URI) (n = 359,246) among children 0–4 years of age were collected from hospitals in the Atlanta, Georgia, area for the period 1993–2010. Daily pollutant measurements were combined across monitoring stations using population weighting. In Poisson generalized linear models, 3-day moving average concentrations of ozone, nitrogen dioxide, and the organic carbon fraction of particulate matter less than 2.5 μm in diameter (PM2.5) were associated with ED visits for pneumonia and URI. Ozone associations were strongest and were observed at low (cold-season) concentrations; a 1–interquartile range increase predicted a 4% increase (95% confidence interval: 2%, 6%) in visits for URI and an 8% increase (95% confidence interval: 4%, 13%) in visits for pneumonia. Rate ratios tended to be higher in the 1- to 4-year age group compared with infants. Results suggest that primary traffic pollutants, ozone, and the organic carbon fraction of PM2.5 exacerbate upper and lower respiratory infections in early life, and that the carbon fraction of PM2.5 is a particularly harmful component of the ambient particulate matter mixture. PMID:25324558
Darrow, Lyndsey A; Klein, Mitchel; Flanders, W Dana; Mulholland, James A; Tolbert, Paige E; Strickland, Matthew J
2014-11-15
Upper and lower respiratory infections are common in early childhood and may be exacerbated by air pollution. We investigated short-term changes in ambient air pollutant concentrations, including speciated particulate matter less than 2.5 μm in diameter (PM2.5), in relation to emergency department (ED) visits for respiratory infections in young children. Daily counts of ED visits for bronchitis and bronchiolitis (n = 80,399), pneumonia (n = 63,359), and upper respiratory infection (URI) (n = 359,246) among children 0-4 years of age were collected from hospitals in the Atlanta, Georgia, area for the period 1993-2010. Daily pollutant measurements were combined across monitoring stations using population weighting. In Poisson generalized linear models, 3-day moving average concentrations of ozone, nitrogen dioxide, and the organic carbon fraction of particulate matter less than 2.5 μm in diameter (PM2.5) were associated with ED visits for pneumonia and URI. Ozone associations were strongest and were observed at low (cold-season) concentrations; a 1-interquartile range increase predicted a 4% increase (95% confidence interval: 2%, 6%) in visits for URI and an 8% increase (95% confidence interval: 4%, 13%) in visits for pneumonia. Rate ratios tended to be higher in the 1- to 4-year age group compared with infants. Results suggest that primary traffic pollutants, ozone, and the organic carbon fraction of PM2.5 exacerbate upper and lower respiratory infections in early life, and that the carbon fraction of PM2.5 is a particularly harmful component of the ambient particulate matter mixture. PMID:25324558
Developmental milestones record - 4 years
Normal childhood growth milestones - 4 years; Growth milestones for children - 4 years; Childhood growth milestones - 4 years ... care provider. PHYSICAL AND MOTOR During the fourth year, a child typically: Gains weight at the rate ...
How Sensitively Timed Are Sensitive Periods?
ERIC Educational Resources Information Center
Zener, Rita Schaefer
2003-01-01
Reviews Maria Montessori's view of sensitive periods and examines the kinds of help needed from adults: an open mind, specific help from a prepared learning environment, and challenges presented at the right time. Stresses the universality of sensitive periods and their connection to brain development. Focuses on the unconscious nature and…
Hu, Xuan; Fan, Mingwen; Mulder, Jan; Frencken, J. E.
2015-01-01
Objectives: The aim of the present study was to test the hypothesis that dental caries prevalence and caries experience in primary dentitions has increased over 4 years and to compare the presence of plaque on permanent teeth in child cohorts over 4 years. Materials and Methods: A time-lag study design was used comprising two cohorts of children aged 7 years from the same five primary schools in Wuhan examined in 2007 and 2011. Two calibrated examiners visually assessed plaque accumulation according to the Greene and Vermillion Index and the dentitions according to the Atraumatic Restorative Treatment (ART) caries criteria. Analysis of variance (ANOVA), logistic regression, and Chi-square test were used to test for differences between dependent and independent variables. Results: The 2007 sample consisted of 817 children and the 2011 sample consisted of 1010 children. The prevalence of dental caries (d3mft) was 68.2% in 2007 and 67.7% in 2011, while that of d2mft was 78.5% in 2007 and 71.4% in 2011 (P < 0.0006). The mean d3mft score was 2.8 in 2007 and 3.1 in 2011 (P = 0.046), while the mean d3mfs score was 4.9 in 2007 and 7.3 in 2011 (P < 0.0001). The d3-component of the d3mft index was 73% in 2007 and 69% in 2011, while the f-component was 22% in 2007 and 26% in 2011. The hypothesis was not accepted. The proportion of children with plaque code 3 (extensive coverage) was higher in 2011 (21.8%) than in age mates in 2007 (5.7%). Conclusions: There were no obvious signs that dental caries prevalence had been increased in primary dentitions of this child population between 2007 and 2011. But as the mean caries experience scores at the surface level were higher in 2011 than in 2007, monitoring caries prevalence remains essential, but should start at an earlier age than that covered by this study. Health and educational authorities should collaborate in setting up programs aimed at ensuring good oral health for school children. PMID:26236680
Instability of time-periodic flows
NASA Technical Reports Server (NTRS)
Hall, P.
1985-01-01
The instabilities of some spatially and/or time-periodic flows are discussed, in particular, flows with curved streamlines which can support Taylor-Gortler vortices are described in detail. The simplest flow where this type of instability can occur is that due to the torsional oscillations of an infinitely long circular cylinder. For more complicated spatially varying time-periodic flows, a similar type of instability can occur and is spatially localized near the most unstable positions. When nonlinear effects are considered it is found that the instability modifies the steady streaming boundary layer induced by the oscillatory motion. It is shown that a rapidly rotating cylinder in a uniform flow is susceptible to a related type of instability; the appropriate stability equations are shown to be identical to those which govern the instability of a boussinesq fluid of Prandtl number unity heated time periodically from below.
Pennsylvanian time scales and cycle periods
deV. Klein, G. )
1990-05-01
Geochronological results from central Europe indicate that the duration of Pennsylvanian time is only 19 m.y., compared to the Harland et al. and Palmer estimates of 34 m.y. Prior calculations of Pennsylvanian cycle periods from the midcontinent of North America suggesting a fit with Milankovitch orbital parameters may well be in errors; as a consequence, other mechanisms for possible eustatic sea-level changes represented in those cycles are needed. Calculation of cycle periods of 100 ka or less lack precision in stratigraphic intervals representing ages characterized by error margins of millions of years. Thus, cycle periods may be less reliable as an indicator of global process than previously considered, particularly in rocks of Paleozoic and early and middle Mesozoic age.
ERIC Educational Resources Information Center
Smith, Curt L.
2010-01-01
The purpose of the study was to investigate to what extent do demographic characteristics, high school experience, aspirations and achievement, college experience-academic integration, college experience-social integration, financial aid, and price influence the first-year persistence of African-American students attending 4-year public colleges.…
Analysis of the time scales in time periodic Darcy flows
NASA Astrophysics Data System (ADS)
Zhu, T.; Waluga, C.; Wohlmuth, B.; Manhart, M.
2014-12-01
We investigate unsteady flow in a porous medium under time - periodic (sinusoidal) pressure gradient. DNS were performed to benchmark the analytical solution of the unsteady Darcy equation with two different expressions of the time scale : one given by a consistent volume averaging of the Navier - Stokes equation [1] with a steady state closure for the flow resistance term, another given by volume averaging of the kinetic energy equation [2] with a closure for the dissipation rate . For small and medium frequencies, the analytical solutions with the time scale obtained by the energy approach compare well with the DNS results in terms of amplitude and phase lag. For large frequencies (f > 100 [Hz]) we observe a slightly smaller damping of the amplitude. This study supports the use of the unsteady form of Darcy's equation with constant coefficients to solve time - periodic Darcy flows at low and medium frequencies. Our DNS simulations, however, indicate that the time scale predicted by the VANS approach together with a steady - state closure for the flow resistance term is too small. The one obtained by the energy approach matches the DNS results well. At large frequencies, the amplitudes deviate slightly from the analytical solution of the unsteady Darcy equation. Note that at those high frequencies, the flow amplitudes remain below 1% of those of steady state flow. This result indicates that unsteady porous media flow can approximately be described by the unsteady Darcy equation with constant coefficients for a large range of frequencies, provided, the proper time scale has been found.
Peñarrocha-Diago, Miguel; Pradíes, Guillermo; Sola-Ruiz, María-Fernanda; Agustín-Panadero, Rubén
2015-01-01
Objectives: The aim of this study was to evaluate the survival and compare the appearance of different mechanical and biological complications, in screw-retained and cemented-retained single-tooth implant-supported restorations localized in the molar mandibular region, over a period of 1 to 4 years. Material and Methods: A retrospective study was carried out with a total of eighty implant-supported restorations, which were placed in eighty patients for prosthetic rehabilitation of a mandibular molar. Forty patients were rehabilitated with a cemented-retained restoration and the other forty with a screw-retained restoration. The presence of the following complications was recorded for both types of prostheses: Fractures of the ceramic veneering, loosening screws, mucositis and peri-implantitis. Debonding of the restoration was analyzed in the cemented-retained restoration group. The clinical survival of crowns was analyzed with a Kaplan-Meier test and the clinical complications were compared, using a Student t test and Log-rank test. Results: 27 patients registered some complication. The average rate of complications was 37,5% for cemented-retained restorations and 30% for screw-retained restorations. The complications more common in the cemented-retained restoration were the presence of mucositis (14,87%), while in the screw-retained restorations was the loosening screw (20%). Student t test and Log-Rank test found significant differences (p=0,001) between the screw loosening and presence of mucositis. Conclusions: The cemented-retained restorations seem to prevent screw loosening, but the presence of cement seem to increase the complications around the soft tissues, however in the screw-retained restorations the presence of mucositis and peri-implantitis are lower than cemented-retained restorations. The incidence of fracture of ceramic veneering was similar in both groups. Key words:Screw-retained restorations, cemented-retained restorations, screw loosening
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.
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...
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...
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...
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...
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...
NASA Astrophysics Data System (ADS)
Yuan, Rong
2007-06-01
In this paper, we study almost periodic logistic delay differential equations. The existence and module of almost periodic solutions are investigated. In particular, we extend some results of Seifert in [G. Seifert, Almost periodic solutions of certain differential equations with piecewise constant delays and almost periodic time dependence, J. Differential Equations 164 (2000) 451-458].
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.
36 CFR 218.10 - Objection time periods and process.
Code of Federal Regulations, 2011 CFR
2011-07-01
... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Objection time periods and... Objection time periods and process. (a) Time to file an objection. Written objections, including any... of objectors to ensure that their objection is received in a timely manner. (b) Computation of...
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…
36 CFR 219.56 - Objection time periods and process.
Code of Federal Regulations, 2012 CFR
2012-07-01
... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Objection time periods and process. 219.56 Section 219.56 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE PLANNING Pre-Decisional Administrative Review Process § 219.56 Objection time periods and process. (a) Time to file an objection. For a...
36 CFR 219.56 - Objection time periods and process.
Code of Federal Regulations, 2014 CFR
2014-07-01
... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Objection time periods and... AGRICULTURE PLANNING Pre-Decisional Administrative Review Process § 219.56 Objection time periods and process. (a) Time to file an objection. For a new plan, plan amendment, or plan revision for which...
36 CFR 219.56 - Objection time periods and process.
Code of Federal Regulations, 2013 CFR
2013-07-01
... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Objection time periods and... AGRICULTURE PLANNING Pre-Decisional Administrative Review Process § 219.56 Objection time periods and process. (a) Time to file an objection. For a new plan, plan amendment, or plan revision for which...
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
36 CFR 218.26 - Objection time periods.
Code of Federal Regulations, 2013 CFR
2013-07-01
... PROJECT-LEVEL PREDECISIONAL ADMINISTRATIVE REVIEW PROCESS Provisions Specific to Project-Level Proposals Not Authorized Under Healthy Forests Restoration Act § 218.26 Objection time periods. (a) Time to...
36 CFR 218.32 - Objection time periods.
Code of Federal Regulations, 2014 CFR
2014-07-01
... PROJECT-LEVEL PREDECISIONAL ADMINISTRATIVE REVIEW PROCESS Provisions Specific to Proposed Projects Authorized Under the Healthy Forests Restoration Act § 218.32 Objection time periods. (a) Time to file...
36 CFR 218.32 - Objection time periods.
Code of Federal Regulations, 2013 CFR
2013-07-01
... PROJECT-LEVEL PREDECISIONAL ADMINISTRATIVE REVIEW PROCESS Provisions Specific to Proposed Projects Authorized Under the Healthy Forests Restoration Act § 218.32 Objection time periods. (a) Time to file...
36 CFR 218.26 - Objection time periods.
Code of Federal Regulations, 2014 CFR
2014-07-01
... PROJECT-LEVEL PREDECISIONAL ADMINISTRATIVE REVIEW PROCESS Provisions Specific to Project-Level Proposals Not Authorized Under Healthy Forests Restoration Act § 218.26 Objection time periods. (a) Time to...
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...
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...
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 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)...
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)...
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....
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)...
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)...
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...
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...
Threshold dynamics of a time periodic reaction-diffusion epidemic model with latent period
NASA Astrophysics Data System (ADS)
Zhang, Liang; Wang, Zhi-Cheng; Zhao, Xiao-Qiang
2015-05-01
In this paper, we first propose a time-periodic reaction-diffusion epidemic model which incorporates simple demographic structure and the latent period of infectious disease. Then we introduce the basic reproduction number R0 for this model and prove that the sign of R0 - 1 determines the local stability of the disease-free periodic solution. By using the comparison arguments and persistence theory, we further show that the disease-free periodic solution is globally attractive if R0 < 1, while there is an endemic periodic solution and the disease is uniformly persistent if R0 > 1.
Local time dependences of oxygen ENA periodicities at Saturn
NASA Astrophysics Data System (ADS)
Carbary, J. F.; Mitchell, D. G.; Brandt, P. C.
2014-08-01
The periodicities of energetic neutral atoms (90-170 keV oxygens) at Saturn are determined by applying Lomb-Scargle periodogram analyses to energetic neutral atom (ENA) fluxes observed in eight local time sectors of the equatorial plane between 5 and 15 RS (1 RS = 60,268 km). The analyses come from four long intervals (>180 days each) of high-latitude viewing from 2007 to 2013 and represent an essentially global view of Saturn's periodicities. The periodograms display rich and complex structures in local time. Sectors near midnight generally exhibit the strongest periodicities (in terms of highest signal-to-noise ratios) and often show the dual or single periods of the Saturn kilometric radiation (SKR). Sectors near noon display single or multiple periodicities or none. Furthermore, dayside periods may be much shorter (~10.3 h) than SKR periods. Sectors near dawn or dusk display periodicities intermediate between midnight and noon or may show no periodicities whatsoever. These patterns of local time dependence do not remain constant from interval to interval.
Particle energization through time-periodic helical magnetic fields.
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. PMID:24827325
Identifying multiple periodicities in sparse photon event time series
NASA Astrophysics Data System (ADS)
Koen, Chris
2016-07-01
The data considered are event times (e.g. photon arrival times, or the occurrence of sharp pulses). The source is multiperiodic, or the data could be multiperiodic because several unresolved sources contribute to the time series. Most events may be unobserved, either because the source is intermittent, or because some events are below the detection limit. The data may also be contaminated by spurious pulses. The problem considered is the determination of the periods in the data. A two-step procedure is proposed: in the first, a likely period is identified; in the second, events associated with this periodicity are removed from the time series. The steps are repeated until the remaining events do not exhibit any periodicity. A number of period-finding methods from the literature are reviewed, and a new maximum likelihood statistic is also introduced. It is shown that the latter is competitive compared to other techniques. The proposed methodology is tested on simulated data. Observations of two rotating radio transients are discussed, but contrary to claims in the literature, no evidence for multiperiodicity could be found.
Identifying Multiple Periodicities in Sparse Photon Event Time Series
NASA Astrophysics Data System (ADS)
Koen, Chris
2016-04-01
The data considered are event times (e.g. photon arrival times, or the occurrence of sharp pulses). The source is multiperiodic, or the data could be multiperiodic because several unresolved sources contribute to the time series. Most events may be unobserved, either because the source is intermittent, or because some events are below the detection limit. The data may also be contaminated by spurious pulses. The problem considered is the determination of the periods in the data. A two-step procedure is proposed: in the first, a likely period is identified; in the second, events associated with this periodicity are removed from the time series. The steps are repeated until the remaining events do not exhibit any periodicity. A number of period-finding methods from the literature are reviewed, and a new maximum likelihood statistic is also introduced. It is shown that the latter is competitive compared to other techniques. The proposed methodology is tested on simulated data. Observations of two rotating radio transients are discussed, but contrary to claims in the literature, no evidence for multiperiodicity could be found.
Optimal health insurance for multiple goods and time periods.
Ellis, Randall P; Jiang, Shenyi; Manning, Willard G
2015-05-01
We examine the efficiency-based arguments for second-best optimal health insurance with multiple treatment goods and multiple time periods. Correlated shocks across health care goods and over time interact with complementarity and substitutability to affect optimal cost sharing. Health care goods that are substitutes or have positively correlated demand shocks should have lower optimal patient cost sharing. Positive serial correlations of demand shocks and uncompensated losses that are positively correlated with covered health services also reduce optimal cost sharing. Our results rationalize covering pharmaceuticals and outpatient spending more fully than is implied by static, one good, or one period models. PMID:25727031
Outpatient angioplasty: 4-year experience in one practice.
Payne, S. P.; Stanton, A.; Travers, P.; Glenn, D.; Hanel, K. C.
1997-01-01
Angioplasty is often performed as an inpatient procedure after preliminary angiography. In order to increase efficiency and patient comfort we introduced a policy of performing angioplasty for chronic leg ischaemia as an outpatient whenever possible, using duplex scanning to select suitable lesions. This paper examines the safety and feasibility of this policy over a 4-year period. We prospectively assessed 168 consecutive cases which were planned for outpatient angioplasty from a total of 190 cases undergoing angioplasty and found full agreement between duplex scanning and angiography in 92%. Six patients (4%) developed complications of angioplasty requiring admission and another five were admitted for unexpected organisational reasons. Thus, the complication rate of outpatient angioplasty was 4%. All complications were noted at the time of angioplasty with no unexpected readmissions. Angioplasty for leg ischaemia is feasible and safe to perform as an outpatient using duplex scanning to select appropriate cases. PMID:9326123
26 CFR 301.7701(b)-4 - Residency time periods.
Code of Federal Regulations, 2010 CFR
2010-04-01
... statement (described in paragraph (c)(3)(v)(C) of this section) to the individual's income tax return (Form... tax return for the election year, the alien individual may request an extension of time for filing the return until a reasonable period after he or she has satisfied such test, provided that the...
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 ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS PRESCRIPTIONS IN FERC HYDROPOWER LICENSES...
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...
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...
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...
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...
36 CFR 218.10 - Objection time periods and process.
Code of Federal Regulations, 2012 CFR
2012-07-01
... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Objection time periods and process. 218.10 Section 218.10 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE PREDECISIONAL ADMINISTRATIVE REVIEW PROCESSES Predecisional Administrative Review Process for Hazardous Fuel Reduction Projects Authorized...
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…
Positive particle frequencies in some time-periodic universes
NASA Astrophysics Data System (ADS)
Droz-Vincent, Philippe
1996-03-01
We consider the Klein-Gordon equation in FRW-like universes which are periodic in a suitable scale of time. In a remarkable sector of solutions, the Floquet theory of differential equations allows for generalizing the notion of particle frequency. In this sense, the sesquilinear form associated with Gordon's current is positive definite when restricted to the sub-sector of positive frequencies.
36 CFR 218.10 - Objection time periods and process.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Objection time periods and process. 218.10 Section 218.10 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF... Hazardous Fuel Reduction Projects Authorized by the Healthy Forests Restoration Act of 2003 §...
False periodicities in quasar time-domain surveys
NASA Astrophysics Data System (ADS)
Vaughan, S.; Uttley, P.; Markowitz, A. G.; Huppenkothen, D.; Middleton, M. J.; Alston, W. N.; Scargle, J. D.; Farr, W. M.
2016-09-01
There have recently been several reports of apparently periodic variations in the light curves of quasars, e.g. PG 1302-102 by Graham et al. Any quasar showing periodic oscillations in brightness would be a strong candidate to be a close binary supermassive black hole and, in turn, a candidate for gravitational wave studies. However, normal quasars - powered by accretion on to a single, supermassive black hole - usually show stochastic variability over a wide range of time-scales. It is therefore important to carefully assess the methods for identifying periodic candidates from among a population dominated by stochastic variability. Using a Bayesian analysis of the light curve of PG 1302-102, we find that a simple stochastic process is preferred over a sinusoidal variation. We then discuss some of the problems one encounters when searching for rare, strictly periodic signals among a large number of irregularly sampled, stochastic time series, and use simulations of quasar light curves to illustrate these points. From a few thousand simulations of steep spectrum (`red noise') stochastic processes, we find many simulations that display few-cycle periodicity like that seen in PG 1302-102. We emphasize the importance of calibrating the false positive rate when the number of targets in a search is very large.
Time-periodic solutions of the Benjamin-Ono equation
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.
4-Year Cohort Graduation Rate: Overview
ERIC Educational Resources Information Center
Pennsylvania Department of Education, 2010
2010-01-01
Federal law requires Pennsylvania, and all other states, to transition to a new calculation method for determining high school graduation rates. Beginning in 2012, using graduation data from the Classes of 2010 and 2011, the "4-Year Cohort Graduation Rate" calculation will replace the "4-Year Leaver Graduation Rate" calculation. The new…
Navarro, C; Fernández, J M; Domínguez, C; Fachal, C; Alvarez, M
1996-01-01
We treated a 28-year-old woman who had metachromatic leukodystrophy with bone marrow transplantation. Leukocyte arylsulfatase A levels increased to the donor's range after successful graft. Motor and sensory nerve conduction values did not change significantly in the 4 years after the transplant, and subcortical white matter lesions, as shown on MRI, remained stable during that period of time. The results, after 4 years of follow-up, indicate that the disease has not progressed and signs and symptoms are stabilized. PMID:8559389
Periodicity detection method for small-sample time series datasets.
Tominaga, Daisuke
2010-01-01
Time series of gene expression often exhibit periodic behavior under the influence of multiple signal pathways, and are represented by a model that incorporates multiple harmonics and noise. Most of these data, which are observed using DNA microarrays, consist of few sampling points in time, but most periodicity detection methods require a relatively large number of sampling points. We have previously developed a detection algorithm based on the discrete Fourier transform and Akaike's information criterion. Here we demonstrate the performance of the algorithm for small-sample time series data through a comparison with conventional and newly proposed periodicity detection methods based on a statistical analysis of the power of harmonics.We show that this method has higher sensitivity for data consisting of multiple harmonics, and is more robust against noise than other methods. Although "combinatorial explosion" occurs for large datasets, the computational time is not a problem for small-sample datasets. The MATLAB/GNU Octave script of the algorithm is available on the author's web site: http://www.cbrc.jp/%7Etominaga/piccolo/. PMID:21151841
Finding unstable periodic orbits from chaotic time series
NASA Astrophysics Data System (ADS)
Buhl, Michael
Contained within a chaotic attractor is an infinite number of unstable periodic orbits (UPOs). Although these orbits have zero measure, they form a skeleton of the dynamics. However, they are difficult to find from an observed time series. In this thesis I present several methods to find UPOs from measured time series. In Chapter 2 I look at data measured from the stomatogastric system of the California spiny lobster as an example to find unstable periodic orbits. With this time series I use two methods. The first creates a local linear model of the dynamics and finds the periodic orbits of the model, and the second applies a linear transform to the model such that unstable orbits are stable. In addition, in this chapter I describe methods of filtering and embedding the chaotic time series. In Chapter 3 I look at a more complicated model system where the dynamics are described by delay differential equations. Now the future state of the system depends on both the current state and the state a time tau earlier. This makes the phase space of the system infinite dimensional. I present a method for modeling systems such as this and finding UPOs in the infinite dimensional phase space. In Chapters 4 and 5 I describe a new method to find UPOs using symbolic dynamics. This has many advantages over the methods described in Chapter 2; more orbits can be found using a smaller time series---even in the presence of noise. First in Chapter 4 I describe how the phase space can be partitioned so that we can use symbolic dynamics. Then in Chapter 5 I describe how the UPOs can be found from the symbolic time series. Here, I model the symbolic dynamics with a Markov chain, represented by a graph, and then the symbolic UPOs are found from the graph. These symbolic cycles can then be localized back in phase space.
Periodic, Quasi-periodic and Chaotic Dynamics in Simple Gene Elements with Time Delays
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
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.
Short time transient periodicities from Cyg X-1
NASA Technical Reports Server (NTRS)
Auriemma, G.; Cardini, D.; Costa, E.; Giovannelli, F.; Ranieri, M.
1976-01-01
The temporal behavior of three new events of modulated optical emission from Cyg X1, detected in July 1975, is presented. Short time periodicities in the optical band are investigated. Single photon pulses from the photomultiplier are recorded on magnetic tape together with a very accurate 1 kHz reference frequency. During playback of the tape, the reference signal gives a 1 ms timing to a scaler interfaced with a small processor and the number of photon per millisecond is recorded on a digital tape.
Krylov-subspace acceleration of time periodic waveform relaxation
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.
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.
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.
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.
(abstract) Short Time Period Variations in Jupiter's Synchrotron Radiation
NASA Technical Reports Server (NTRS)
Bolton, S. J.; Klein, M. J.; Gulkis, S.; Foster, R.; Heiles, C.; Pater, I. de
1994-01-01
The long term time variability of Jupiter's synchrotron radiation on yearly time scales has been established for some time. For many years, theorists have speculated about the effects variations in the solar wind, solar flux, Io, the Io torus, and Jupiter's magnetic field have on the ultra-relativistic electron population responsible for the emission. Early observational results suggested the additional possibility of a short term time variability, on timescales of days to weeks. In 1989 a program designed to investigate the existence of short term time variability using the 85 foot Hat Creek radio telescope operating at 1400 MHz was initiated. The availability of a dedicated telescope provided the opportunity, for the first time, to obtain numerous observations over the full Jupiter rotation period. These and future observations will enable two important studies, characterization and confirmation of possible short term variations, and the investigation of the stability of Jupiter's synchrotron emission beaming curve. Analysis of Hat Creek observations and early results from the Maryland Point Naval research Laboratory will be presented.
Polymer dynamics in time-dependent periodic potentials
NASA Astrophysics Data System (ADS)
Kauttonen, Janne; Merikoski, Juha; Pulkkinen, Otto
2008-06-01
The dynamics of a discrete polymer in time-dependent external potentials is studied with the master equation approach. We consider both stochastic and deterministic switching mechanisms for the potential states and give the essential equations for computing the stationary-state properties of molecules with internal structure in time-dependent periodic potentials on a lattice. As an example, we consider standard and modified Rubinstein-Duke polymers and calculate their mean drift and effective diffusion coefficient in the two-state nonsymmetric flashing potential and symmetric traveling potential. Rich nonlinear behavior of these observables is found. By varying the polymer length, we find current inversions caused by the rebound effect that is only present for molecules with internal structure. These results depend strongly on the polymer type. We also notice increased transport coherence for longer polymers.
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.
Desensitization to media violence over a short period of time.
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. PMID:19172659
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.
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.
14 CFR 221.190 - Time for filing and computation of time periods.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Time for filing and computation of time periods. 221.190 Section 221.190 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS TARIFFS Electronically Filed Tariffs § 221.190...
14 CFR 221.190 - Time for filing and computation of time periods.
Code of Federal Regulations, 2011 CFR
2011-01-01
... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Time for filing and computation of time periods. 221.190 Section 221.190 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS TARIFFS Electronically Filed Tariffs § 221.190...
14 CFR 221.190 - Time for filing and computation of time periods.
Code of Federal Regulations, 2012 CFR
2012-01-01
... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Time for filing and computation of time periods. 221.190 Section 221.190 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS TARIFFS Electronically Filed Tariffs § 221.190...
14 CFR 221.190 - Time for filing and computation of time periods.
Code of Federal Regulations, 2014 CFR
2014-01-01
... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Time for filing and computation of time periods. 221.190 Section 221.190 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS TARIFFS Electronically Filed Tariffs § 221.190...
14 CFR 221.190 - Time for filing and computation of time periods.
Code of Federal Regulations, 2013 CFR
2013-01-01
... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Time for filing and computation of time periods. 221.190 Section 221.190 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS TARIFFS Electronically Filed Tariffs § 221.190...
43 CFR 3207.5 - What terms (time periods) apply to my lease?
Code of Federal Regulations, 2011 CFR
2011-10-01
... LEASING Lease Terms and Extensions § 3207.5 What terms (time periods) apply to my lease? Your lease may include a number of different time periods. Not every time period applies to every lease. These periods... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false What terms (time periods) apply to...
NASA Astrophysics Data System (ADS)
Wang, Chao; Agarwal, Ravi P.
2016-07-01
In this paper, we improve the new concepts of almost periodic time scales addressed in 2014 to introduce the new concepts of piecewise almost periodic functions. Then we establish some first results for the existence and exponential stability of almost periodic solution for a general type of delay neural networks with impulsive effects. The approaches are based on contraction principle and Gronwall-Bellman's inequality. In addition, the numerical example and simulations are provided to illustrate our time scale methods are feasible and effective. The obtained results are more general and comprehensive than the results obtained on periodic time scales before.
Convergence Time towards Periodic Orbits in Discrete Dynamical Systems
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. PMID:24736594
Convergence time towards periodic orbits in discrete dynamical systems.
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. PMID:24736594
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.
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...
29 CFR 4000.43 - How do I compute a time period?
Code of Federal Regulations, 2011 CFR
2011-07-01
... 29 Labor 9 2011-07-01 2011-07-01 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...
29 CFR 4000.43 - How do I compute a time period?
Code of Federal Regulations, 2012 CFR
2012-07-01
... 29 Labor 9 2012-07-01 2012-07-01 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...
29 CFR 4000.43 - How do I compute a time period?
Code of Federal Regulations, 2014 CFR
2014-07-01
... 29 Labor 9 2014-07-01 2014-07-01 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...
29 CFR 4000.43 - How do I compute a time period?
Code of Federal Regulations, 2013 CFR
2013-07-01
... 29 Labor 9 2013-07-01 2013-07-01 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...
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.
Unsettled Times, Unsettled Prices: Periodical Price Survey 1997.
ERIC Educational Resources Information Center
Ketcham, Lee; Born, Kathleen
1997-01-01
Presents the results of the thirty-seventh annual periodical price survey conducted by "Library Journal". Highlights include canceling print subscriptions and electronic journals, cost trends by subject and by countries, prices for public and school libraries and for college and medium-sized university libraries, and budgeting for 1988. (LRW)
Asymptotic stability on slow time scales from periodic systems
Persek, S.C.
1981-08-01
Asymptotic stability for a periodic system of ordinary differential equations with a small parameter is shown to follow from the stability of the corresponding iterated-average system. Applications are made to biological systems experiencing varying seasonal factors, to large scale dynamical systems that are principally irrotational and to nuclear reactor dynamics. 7 refs.
Using travel times to simulate multi-dimensional bioreactive transport in time-periodic flows.
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
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.
NASA Astrophysics Data System (ADS)
Louarroudi, E.; Pintelon, R.; Lataire, J.
2014-10-01
Time-periodic (TP) phenomena occurring, for instance, in wind turbines, helicopters, anisotropic shaft-bearing systems, and cardiovascular/respiratory systems, are often not addressed when classical frequency response function (FRF) measurements are performed. As the traditional FRF concept is based on the linear time-invariant (LTI) system theory, it is only approximately valid for systems with varying dynamics. Accordingly, the quantification of any deviation from this ideal LTI framework is more than welcome. The “measure of deviation” allows us to define the notion of the best LTI (BLTI) approximation, which yields the best - in mean square sense - LTI description of a linear time-periodic LTP system. By taking into consideration the TP effects, it is shown in this paper that the variability of the BLTI measurement can be reduced significantly compared with that of classical FRF estimators. From a single experiment, the proposed identification methods can handle (non-)linear time-periodic [(N)LTP] systems in open-loop with a quantification of (i) the noise and/or the NL distortions, (ii) the TP distortions and (iii) the transient (leakage) errors. Besides, a geometrical interpretation of the BLTI approximation is provided, leading to a framework called vector FRF analysis. The theory presented is supported by numerical simulations as well as real measurements mimicking the well-known mechanical Mathieu oscillator.
SMOS Mission completes 4 years in orbit
NASA Astrophysics Data System (ADS)
Kerr, Yann; Richaume, Philippe; Mialon, Arnaud; Cabot, François; Bitar, Ahmad Al; Delwart, Steven; Drush, Matthias; Mecklenburg, Susanne
2014-05-01
In early November 2013, the SMOS mission celebrated 4 years in orbit. Since its launch, this mission has given many opportunities for breaking new grounds. Shortly after launch, first global maps of soil moisture ever measured from space were produced. Since then, the achieved accuracy has continuously improved to match the requirements. The long term trends of surface moisture can now be closely linked to precipitation regime, and SMOS results have been successfully used in response to extreme events. On the other hand, ocean salinity results have also improved dramatically. Here again, some amazing results regarding river plumes or fresh water pools related to precipitation have been obtained. At last, new applications have been imagined in various fields such as of sea ice thickness, or hurricane winds. This presentation will give an extensive status of the mission, emphasizing the many lessons learned and demonstrating some outstanding results. Some perspectives on the mission and future missions will also be given. A particular emphasis will be given on new level 4 products currently being produced as well as comparisons with other existing sensors.
The nature of species interactions shifts profoundly between time periods
Technology Transfer Automated Retrieval System (TEKTRAN)
Species interactions change through time, for example ontogenetically, successionally, and evolutionarily. They also change as environmental conditions change, both within years (seasonally) and between years (year effects). The former are relatively well-studied, but the latter have received less a...
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.
New times of minimum and a period study for GO Cygni
NASA Technical Reports Server (NTRS)
Hall, Douglas S.; Louth, Howard
1990-01-01
Times of minimum derived from photometry obtained in 1963, 1967, 1978, and 1979 are presented. With these and previously published times, the period is studied. A constant period increase (quadratic ephemeris) represents most of the times but there was a period decrease in 1934 and possibly in 1984. A 50-year magnetic cycle is discussed.
19 CFR 351.204 - Time periods and persons examined; voluntary respondents; exclusions.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 19 Customs Duties 3 2011-04-01 2011-04-01 false Time periods and persons examined; voluntary... § 351.204 Time periods and persons examined; voluntary respondents; exclusions. (a) Introduction. Because the Act does not specify the precise period of time that the Secretary should examine in...
20 CFR 261.10 - Increase in future benefits where time period for reopening has expired.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Increase in future benefits where time period... where time period for reopening has expired. If, after the time period for reopening under § 261.2(b) of this part has expired, new evidence is furnished showing a different date of birth or new evidence...
12 CFR 390.102 - How does the FDIC compute time periods under this subpart?
Code of Federal Regulations, 2014 CFR
2014-01-01
... 12 Banks and Banking 5 2014-01-01 2014-01-01 false How does the FDIC compute time periods under... Application Processing Procedures § 390.102 How does the FDIC compute time periods under this subpart? In computing time periods under this subpart, the FDIC does not include the day of the act or event...
12 CFR 390.102 - How does the FDIC compute time periods under this subpart?
Code of Federal Regulations, 2013 CFR
2013-01-01
... 12 Banks and Banking 5 2013-01-01 2013-01-01 false How does the FDIC compute time periods under... Application Processing Procedures § 390.102 How does the FDIC compute time periods under this subpart? In computing time periods under this subpart, the FDIC does not include the day of the act or event...
12 CFR 116.10 - How does the OCC compute time periods under this part?
Code of Federal Regulations, 2012 CFR
2012-01-01
... 12 Banks and Banking 1 2012-01-01 2012-01-01 false How does the OCC compute time periods under... TREASURY APPLICATION PROCESSING PROCEDURES § 116.10 How does the OCC compute time periods under this part? In computing time periods under this part, the OCC does not include the day of the act or event...
12 CFR 116.10 - How does the OCC compute time periods under this part?
Code of Federal Regulations, 2014 CFR
2014-01-01
... 12 Banks and Banking 1 2014-01-01 2014-01-01 false How does the OCC compute time periods under... TREASURY APPLICATION PROCESSING PROCEDURES § 116.10 How does the OCC compute time periods under this part? In computing time periods under this part, the OCC does not include the day of the act or event...
12 CFR 390.102 - How does the FDIC compute time periods under this subpart?
Code of Federal Regulations, 2012 CFR
2012-01-01
... 12 Banks and Banking 5 2012-01-01 2012-01-01 false How does the FDIC compute time periods under... Application Processing Procedures § 390.102 How does the FDIC compute time periods under this subpart? In computing time periods under this subpart, the FDIC does not include the day of the act or event...
12 CFR 116.10 - How does the OCC compute time periods under this part?
Code of Federal Regulations, 2013 CFR
2013-01-01
... 12 Banks and Banking 1 2013-01-01 2013-01-01 false How does the OCC compute time periods under... TREASURY APPLICATION PROCESSING PROCEDURES § 116.10 How does the OCC compute time periods under this part? In computing time periods under this part, the OCC does not include the day of the act or event...
Estimation of Maximum Likelihood of the Unextendable Dead Time Period in a Flow of Physical Events
NASA Astrophysics Data System (ADS)
Gortsev, A. M.; Solov'ev, A. A.
2016-03-01
A flow of physical events (photons, electrons, etc.) is studied. One of the mathematical models of such flows is the MAP-flow of events. The flow circulates under conditions of the unextendable dead time period, when the dead time period is unknown. The dead time period is estimated by the method of maximum likelihood from observations of arrival instants of events.
Controlling mixing and segregation in time periodic granular flows
NASA Astrophysics Data System (ADS)
Bhattacharya, Tathagata
Segregation is a major problem for many solids processing industries. Differences in particle size or density can lead to flow-induced segregation. In the present work, we employ the discrete element method (DEM)---one type of particle dynamics (PD) technique---to investigate the mixing and segregation of granular material in some prototypical solid handling devices, such as a rotating drum and chute. In DEM, one calculates the trajectories of individual particles based on Newton's laws of motion by employing suitable contact force models and a collision detection algorithm. Recently, it has been suggested that segregation in particle mixers can be thwarted if the particle flow is inverted at a rate above a critical forcing frequency. Further, it has been hypothesized that, for a rotating drum, the effectiveness of this technique can be linked to the probability distribution of the number of times a particle passes through the flowing layer per rotation of the drum. In the first portion of this work, various configurations of solid mixers are numerically and experimentally studied to investigate the conditions for improved mixing in light of these hypotheses. Besides rotating drums, many studies of granular flow have focused on gravity driven chute flows owing to its practical importance in granular transportation and to the fact that the relative simplicity of this type of flow allows for development and testing of new theories. In this part of the work, we observe the deposition behavior of both mono-sized and polydisperse dry granular materials in an inclined chute flow. The effects of different parameters such as chute angle, particle size, falling height and charge amount on the mass fraction distribution of granular materials after deposition are investigated. The simulation results obtained using DEM are compared with the experimental findings and a high degree of agreement is observed. Tuning of the underlying contact force parameters allows the achievement
NASA Astrophysics Data System (ADS)
Shapiro, M.; Brenner, H.
1990-10-01
Generalized Taylor dispersion theory is herein extended to circumstances for which the transport of dissolved or suspended chemically reactive (as well as inert) solutes is affected by carrier-solvent flow fields and/or external forces that are time periodic in both their global and local microscale spaces (and possess commensurate frequencies). The local-space- and time-averaged solute transport process is characterized by three time-independent, but frequency-dependent microscale phenomenological coefficients—K¯*, Ū*, and cf6D*, representing the mean chemical reaction rate, velocity vector, and dispersivity dyadic of the solute, respectively. These macroscale transport coefficients are expressed in terms of time-periodic eigenfunctions and corresponding eigenvalues using a recently developed solution scheme. This scheme permits the analysis of phenomena involving time-periodic transport coefficients on a par with that for the classical case of time-independent microscale phenomenological coefficients. The analysis generalizes to time-periodic local-space phenomena a previous treatment, in which only the global-space coefficients were allowed to vary periodically with time. This greatly enlarges the scope of potential applications of the analysis. In addition to the time-averaged phenomenological coefficients K¯*, Ū*, and CF6D*, comparable instantaneous coefficients are defined governing the local-space-averaged instantaneous solute concentration. In contrast with their time-averaged counterparts, K¯*, Ū*, and CF6D*, the latter instantaneous transport coefficients are shown to depend upon the initial solute distribution within the local space. Because of coupling between the local- and global-space transport processes in oscillatory flows and/or oscillatory external force fields, all harmonics of the resulting global-space solute velocity field contribute to the mean convective solute transport. This phenomenon may result, for example, in zero solvent
14 CFR 135.273 - Duty period limitations and rest time requirements.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Duty period limitations and rest time requirements. 135.273 Section 135.273 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Crewmember Flight Time and Duty Period Limitations and Rest Requirements § 135.273 Duty period...
14 CFR 135.273 - Duty period limitations and rest time requirements.
Code of Federal Regulations, 2011 CFR
2011-01-01
... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Duty period limitations and rest time requirements. 135.273 Section 135.273 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... Crewmember Flight Time and Duty Period Limitations and Rest Requirements § 135.273 Duty period...
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.
A 4-year investigation into phonetic inventory development in young cochlear implant users.
Serry, T A; Blamey, P J
1999-02-01
Phonetic inventories of 9 children with profoundly impaired hearing who used the 22-electrode cochlear implant (Cochlear Limited) were monitored before implantation and during the first 4 years of implant use. All children were 5 years old or younger at the time of implant. Spontaneous speech samples were collected at regular intervals for each child and analyzed to investigate phone acquisition over the post-implant period. Acquisition was measured using two different criteria. The "targetless" criterion required the child to produce a phonetically recognizable sound spontaneously, and the "target" criterion required the child to produce the phone correctly at least 50% of the time in meaningful words. At 4 years post-implant, 40 out of 44 phones (91 %) had reached the targetless criterion, and 29 phones (66%) had reached the target criterion for 5 or more of the children. Over the time of the study 100% of monophthongs, 63% of diphthongs, and 54% of consonants reached the target criterion. The average time taken for a phone to progress from the targetless to target criterion was 15 months. Overall, the data suggest trends in the order of phone acquisition similar to those of normally hearing children, although the process of acquisition occurred at a slower rate. PMID:10025550
Mars Exploration Rovers: 4 Years on Mars
NASA Technical Reports Server (NTRS)
Landis, Geoffrey A.
2008-01-01
This January, the Mars Exploration Rovers "Spirit" and "Opportunity" are starting their fifth year of exploring the surface of Mars, well over ten times their nominal 90-day design lifetime. This lecture discusses the Mars Exploration Rovers, presents the current mission status for the extended mission, some of the most results from the mission and how it is affecting our current view of Mars, and briefly presents the plans for the coming NASA missions to the surface of Mars and concepts for exploration with robots and humans into the next decade, and beyond.
20 CFR 404.996 - Increase in future benefits where time period for reopening expires.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Increase in future benefits where time period for reopening expires. 404.996 Section 404.996 Employees' Benefits SOCIAL SECURITY ADMINISTRATION... § 404.996 Increase in future benefits where time period for reopening expires. If, after the time...
20 CFR 404.996 - Increase in future benefits where time period for reopening expires.
Code of Federal Regulations, 2014 CFR
2014-04-01
... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false Increase in future benefits where time period for reopening expires. 404.996 Section 404.996 Employees' Benefits SOCIAL SECURITY ADMINISTRATION... § 404.996 Increase in future benefits where time period for reopening expires. If, after the time...
20 CFR 404.996 - Increase in future benefits where time period for reopening expires.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Increase in future benefits where time period for reopening expires. 404.996 Section 404.996 Employees' Benefits SOCIAL SECURITY ADMINISTRATION... § 404.996 Increase in future benefits where time period for reopening expires. If, after the time...
20 CFR 404.996 - Increase in future benefits where time period for reopening expires.
Code of Federal Regulations, 2012 CFR
2012-04-01
... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false Increase in future benefits where time period for reopening expires. 404.996 Section 404.996 Employees' Benefits SOCIAL SECURITY ADMINISTRATION... § 404.996 Increase in future benefits where time period for reopening expires. If, after the time...
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...
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...
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...
19 CFR 351.204 - Time periods and persons examined; voluntary respondents; exclusions.
Code of Federal Regulations, 2010 CFR
2010-04-01
... § 351.204 Time periods and persons examined; voluntary respondents; exclusions. (a) Introduction... fiscal quarters (or, in an investigation involving merchandise imported from a nonmarket economy...
Longitudinal study of amygdala volume and joint attention in 2- to 4-year-old children with autism
Mosconi, Matthew W.; Hazlett, Heather Cody; Poe, Michele D.; Gerig, Guido; Smith, Rachel Gimpel
2011-01-01
Context Cerebral cortical volume enlargement has been reported in 2- to 4-year-olds with autism. Little is known about the volume of sub-regions during this period of development. The amygdala is hypothesized to be abnormal in volume and related to core clinical features in autism. Objective To examine amygdala volume at 2 years with follow-up at 4 years of age in children with autism and to explore the relationship between amygdala volume and selected behavioral features of autism. Design Longitudinal magnetic resonance imaging study. Setting University medical setting. Participants Fifty-two autistic and 33 control (11 developmentally delayed, 22 typically developing) children between 18 and 35 months (2 years) of age followed up at 42 to 59 months (4 years) of age. Main Outcome Measures Amygdala volumes in relation to joint attention ability measured with a new observational coding system, the Social Orienting Continuum and Response scale; group comparisons including total tissue volume, sex, IQ and age as covariates. Results Amygdala enlargement was observed in subjects with autism at both 2 and 4 years of age. Significant change over time in volume was observed, though the rate of change did not differ between groups. Amygdala volume was associated with joint attention ability at age 4 years in subjects with autism. Conclusions The amygdala is enlarged in autism relative to controls by age 2 years but shows no relative increase in magnitude between 2 and 4 years of age. A significant association between amygdala volume and joint attention suggests that alterations to this structure may be linked to a core deficit of autism. PMID:19414710
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.
Fermi Large Area Telescope Operations: Progress Over 4 Years
Cameron, Robert A.; /SLAC
2012-06-28
The Fermi Gamma-ray Space Telescope was launched into orbit in June 2008, and is conducting a multi-year gamma-ray all-sky survey, using the main instrument on Fermi, the Large Area Telescope (LAT). Fermi began its science mission in August 2008, and has now been operating for almost 4 years. The SLAC National Accelerator Laboratory hosts the LAT Instrument Science Operations Center (ISOC), which supports the operation of the LAT in conjunction with the Mission Operations Center (MOC) and the Fermi Science Support Center (FSSC), both at NASA's Goddard Space Flight Center. The LAT has a continuous output data rate of about 1.5 Mbits per second, and data from the LAT are stored on Fermi and transmitted to the ground through TDRS and the MOC to the ISOC about 10 times per day. Several hundred computers at SLAC are used to process LAT data to perform event reconstruction, and gamma-ray photon data are subsequently delivered to the FSSC for public release with a few hours of being detected by the LAT. We summarize the current status of the LAT, and the evolution of the data processing and monitoring performed by the ISOC during the first 4 years of the Fermi mission, together with future plans for further changes to detected event data processing and instrument operations and monitoring.
Dynamics of phase slips in systems with time-periodic modulation
NASA Astrophysics Data System (ADS)
Gandhi, Punit; Knobloch, Edgar; Beaume, Cédric
2015-12-01
The Adler equation with time-periodic frequency modulation is studied. A series of resonances between the period of the frequency modulation and the time scale for the generation of a phase slip is identified. The resulting parameter space structure is determined using a combination of numerical continuation, time simulations, and asymptotic methods. Regions with an integer number of phase slips per period are separated by regions with noninteger numbers of phase slips and include canard trajectories that drift along unstable equilibria. Both high- and low-frequency modulation is considered. An adiabatic description of the low-frequency modulation regime is found to be accurate over a large range of modulation periods.
17 CFR 260.7a-24 - Words relating to periods of time in the past.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Words relating to periods of time in the past. 260.7a-24 Section 260.7a-24 Commodity and Securities Exchanges SECURITIES AND... Requirements As to Contents § 260.7a-24 Words relating to periods of time in the past. Unless the...
17 CFR 260.7a-24 - Words relating to periods of time in the past.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 17 Commodity and Securities Exchanges 3 2011-04-01 2011-04-01 false Words relating to periods of time in the past. 260.7a-24 Section 260.7a-24 Commodity and Securities Exchanges SECURITIES AND... Requirements As to Contents § 260.7a-24 Words relating to periods of time in the past. Unless the...
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...
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...
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...
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 Administrator decisions. 54.724 Section 54.724 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES (CONTINUED) UNIVERSAL SERVICE Review of Decisions Issued by the Administrator § 54.724 Time periods for...
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...
12 CFR 516.10 - How does OTS compute time periods under this part?
Code of Federal Regulations, 2011 CFR
2011-01-01
... 12 Banks and Banking 5 2011-01-01 2011-01-01 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...
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...
12 CFR 516.10 - How does OTS compute time periods under this part?
Code of Federal Regulations, 2013 CFR
2013-01-01
... 12 Banks and Banking 6 2013-01-01 2012-01-01 true 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...
12 CFR 516.10 - How does OTS compute time periods under this part?
Code of Federal Regulations, 2014 CFR
2014-01-01
... 12 Banks and Banking 6 2014-01-01 2012-01-01 true 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...
12 CFR 516.10 - How does OTS compute time periods under this part?
Code of Federal Regulations, 2012 CFR
2012-01-01
... 12 Banks and Banking 6 2012-01-01 2012-01-01 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...
17 CFR 260.7a-24 - Words relating to periods of time in the past.
Code of Federal Regulations, 2014 CFR
2014-04-01
... 17 Commodity and Securities Exchanges 4 2014-04-01 2014-04-01 false Words relating to periods of time in the past. 260.7a-24 Section 260.7a-24 Commodity and Securities Exchanges SECURITIES AND... Requirements As to Contents § 260.7a-24 Words relating to periods of time in the past. Unless the...
17 CFR 260.7a-24 - Words relating to periods of time in the past.
Code of Federal Regulations, 2013 CFR
2013-04-01
... 17 Commodity and Securities Exchanges 3 2013-04-01 2013-04-01 false Words relating to periods of time in the past. 260.7a-24 Section 260.7a-24 Commodity and Securities Exchanges SECURITIES AND... Requirements As to Contents § 260.7a-24 Words relating to periods of time in the past. Unless the...
26 CFR 1.676(b)-1 - Powers exercisable only after a period of time.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 26 Internal Revenue 8 2010-04-01 2010-04-01 false Powers exercisable only after a period of time...)-1 Powers exercisable only after a period of time. Section 676(b) provides an exception to the general rule of section 676(a) when the exercise of a power can only affect the beneficial enjoyment...
Mailey, Emily L.; Gothe, Neha P.; Wójcicki, Thomas R.; Szabo, Amanda N.; Olson, Erin A.; Mullen, Sean P.; Fanning, Jason T.; Motl, Robert W.; McAuley, Edward
2013-01-01
The criteria one uses to reduce accelerometer data can profoundly influence the interpretation of research outcomes. The purpose of this study was to examine the influence of three different interruption periods (i.e., 20, 30, and 60 minutes) on the amount of data retained for analyses and estimates of sedentary time among older adults. Older adults (N=311; Mage=71.1) wore an accelerometer for seven days and reported wear time on an accelerometer log. Accelerometer data were downloaded and scored using 20, 30, and 60-minute interruption periods. Estimates of wear time derived using each interruption period were compared to self-reported wear time, and descriptive statistics were used to compare estimates of sedentary time. Results showed a longer interruption period (i.e., 60 minutes) yields the largest sample size and the closest approximation of self-reported wear time. A short interruption period (i.e., 20 minutes) is likely to underestimate sedentary time among older adults. PMID:23752299
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.
40 CFR 93.162 - Emissions beyond the time period covered by the SIP.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 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...
NHEXAS PHASE I REGION 5 STUDY--TIME-ACTIVITY DIARY QUESTIONNAIRE DATA (ALL MONITORING PERIODS)
This data set includes responses for 249 participants with a total of 428 time-activity diaries. Some participants were studied for more than one monitoring period. The Time Diary and Activity Questionnaire was used for collecting data on detailed (daily) time and location inform...
Li, Yongkun; Li, Bing
2016-01-01
In this paper, we first give a new definition of almost periodic time scales, two new definitions of almost periodic functions on time scales and investigate some basic properties of them. Then, as an application, by using a fixed point theorem in Banach space and the time scale calculus theory, we obtain some sufficient conditions for the existence and exponential stability of positive almost periodic solutions for a class of Nicholson's blowflies models on time scales. Finally, we present an illustrative example to show the effectiveness of obtained results. Our results show that under a simple condition the continuous-time Nicholson's blowflies model and its discrete-time analogue have the same dynamical behaviors. PMID:27468397
An infinite branching hierarchy of time-periodic solutions of the Benjamin-Ono equation
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.
NASA Astrophysics Data System (ADS)
Jupp, Tim E.; Pyle, David M.; Mason, Ben G.; Dade, W. Brian
2004-02-01
Evidence of nonuniformity in the rate of seismicity and volcanicity has been sought on a variety of timescales ranging from ˜12.4 hours (tidal) to 103-104 years (climatic), but the results are mixed. Here, we propose a simple conceptual model for the influence of periodic processes on the frequency of geophysical "failure events" such as earthquakes and volcanic eruptions. In our model a failure event occurs at a "failure time" tF = tI + tR which is controlled by an "initiation event" at the "initiation time" tI and by the "response time" of the system tR. We treat each of the initiation time, the response time, and the failure time as random variables. In physical terms, we define the initiation time to be the time at which a "load function" exceeds a "strength function," and we imagine that the response time tR corresponds to a physical process such as crack propagation or the movement of magma. Assuming that the magnitude and frequency of the periodic process are known, we calculate the statistical distribution of the initiation times on the assumption that the load and strength functions are otherwise linear in time. This allows the distribution of the failure times to be calculated if the distribution of the response times is known also. The quantitative predictions of this simple theory are compared with some examples of observed periodicity in seismic and volcanic activity at tidal and annual timescales.
Time periodic spatial disorder in a complex Ginzburg{endash}Landau equation
Bazhenov, M.; Rabinovich, M.; Rubchinsky, L.
1996-06-01
The phenomenon of time-periodic evolution of spatial chaos (1) is investigated in the frame of a one and two-dimensional complex Ginzburg{endash}Landau equation. It is found that there exists a region of the parameters at which a disordered spatial distribution of the field behaves periodically in time; the boundaries of this region are determined. A system of ordinary differential equations describing spatial disorder is derived. The effect of the size of the system on the shape and period of oscillations is investigated. It is established that in a two-dimensional case the regime of time periodic spatial disorder arises only in the narrow band and the critical width of the band is estimated. The phenomenon investigated in this paper indicates that a family of limit cycles with finite basins may exist in the functional phase space of complex Ginzburg{endash}Landau equation in finite regions of the parameters. {copyright} {ital 1996 American Institute of Physics.}
Dynamics of phase slips in systems with time-periodic modulation.
Gandhi, Punit; Knobloch, Edgar; Beaume, Cédric
2015-12-01
The Adler equation with time-periodic frequency modulation is studied. A series of resonances between the period of the frequency modulation and the time scale for the generation of a phase slip is identified. The resulting parameter space structure is determined using a combination of numerical continuation, time simulations, and asymptotic methods. Regions with an integer number of phase slips per period are separated by regions with noninteger numbers of phase slips and include canard trajectories that drift along unstable equilibria. Both high- and low-frequency modulation is considered. An adiabatic description of the low-frequency modulation regime is found to be accurate over a large range of modulation periods. PMID:26764781
ALEXIS, the little satellite that could -- 4 years later
Roussel-Dupre, D.; Bloch, J.; Little, C.
1997-10-01
The 113-kg Array of Low Energy X-ray Imaging Sensors (ALEXIS) satellite was launched from the fourth flight of Pegasus on 25 April, 1993 into a 750 x 850 km, 70 degree inclination orbit. Due to damage sustained at the time of launch, ground controllers did not make contact with the satellite until late June. By late July, full satellite operations had been restored through the implementation of new procedures for attitude control. Science operations with the two onboard experiments began at that time. Now 4 years later is still collecting more than 100 MB of mission data per day. ALEXIS was originally designed to be a high risk, single string. {open_quotes}Smarter-Faster-Cheaper{close_quotes} satellite, with a 1 year nominal and a 3 year design limit. This paper will discuss how well the various satellite and experiment subsystems are surviving a variety of low and high radiation environments and what improvements have been made to make operations more autonomous. 11 refs., 2 figs., 2 tabs.
Longitudinal relations between child vagal tone and parenting behavior: 2 to 4 years.
Kennedy, Amy E; Rubin, Kenneth H; Hastings, Paul D; Maisel, Beth
2004-07-01
The longitudinal relations between physiological markers of child emotion regulation and maternal parenting practices were examined from 2 to 4 years of age. At Time 1, cardiac vagal tone was assessed for one hundred four 2-year-olds (54 females); their mothers completed an assessment of parenting styles. Two years later, at Time 2, 84 of the original participants were reassessed on measures of cardiac vagal tone and parenting style. Results indicated both baseline cardiac vagal tone and maternal parenting practices to be stable from 2 to 4 years of age. Children's cardiac vagal tone predicted specific parenting practices from the toddler to preschool years. Further, child cardiac vagal tone moderated maternal restrictive-parenting practices from 2 to 4 years of age; mothers of children who were highly or moderately physiologically dysregulated were more likely to report restrictive parenting practices at both 2 and 4 years of age. PMID:15229872
NASA Astrophysics Data System (ADS)
Hwang, Sunghwan
1997-08-01
One of the most prominent features of helicopter rotor dynamics in forward flight is the periodic coefficients in the equations of motion introduced by the rotor rotation. The frequency response characteristics of such a linear time periodic system exhibits sideband behavior, which is not the case for linear time invariant systems. Therefore, a frequency domain identification methodology for linear systems with time periodic coefficients was developed, because the linear time invariant theory cannot account for sideband behavior. The modulated complex Fourier series was introduced to eliminate the smearing effect of Fourier series expansions of exponentially modulated periodic signals. A system identification theory was then developed using modulated complex Fourier series expansion. Correlation and spectral density functions were derived using the modulated complex Fourier series expansion for linear time periodic systems. Expressions of the identified harmonic transfer function were then formulated using the spectral density functions both with and without additive noise processes at input and/or output. A procedure was developed to identify parameters of a model to match the frequency response characteristics between measured and estimated harmonic transfer functions by minimizing an objective function defined in terms of the trace of the squared frequency response error matrix. Feasibility was demonstrated by the identification of the harmonic transfer function and parameters for helicopter rigid blade flapping dynamics in forward flight. This technique is envisioned to satisfy the needs of system identification in the rotating frame, especially in the context of individual blade control. The technique was applied to the coupled flap-lag-inflow dynamics of a rigid blade excited by an active pitch link. The linear time periodic technique results were compared with the linear time invariant technique results. Also, the effect of noise processes and initial
A framework for periodic outlier pattern detection in time-series sequences.
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. PMID:23757597
Finding hidden periodic signals in time series - an application to stock prices
NASA Astrophysics Data System (ADS)
O'Shea, Michael
2014-03-01
Data in the form of time series appear in many areas of science. In cases where the periodicity is apparent and the only other contribution to the time series is stochastic in origin, the data can be `folded' to improve signal to noise and this has been done for light curves of variable stars with the folding resulting in a cleaner light curve signal. Stock index prices versus time are classic examples of time series. Repeating patterns have been claimed by many workers and include unusually large returns on small-cap stocks during the month of January, and small returns on the Dow Jones Industrial average (DJIA) in the months June through September compared to the rest of the year. Such observations imply that these prices have a periodic component. We investigate this for the DJIA. If such a component exists it is hidden in a large non-periodic variation and a large stochastic variation. We show how to extract this periodic component and for the first time reveal its yearly (averaged) shape. This periodic component leads directly to the `Sell in May and buy at Halloween' adage. We also drill down and show that this yearly variation emerges from approximately half of the underlying stocks making up the DJIA index.
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.
A Recurrence Time versus Orbital Period Relation for the Z Camelopardalis Stars
NASA Astrophysics Data System (ADS)
Shafter, Allen W.; Cannizzo, John K.; Waagen, Elizabeth O.
2005-09-01
We examine AAVSO (American Association of Variable Star Observers) light curves of 16 Z Camelopardalis systems with measured orbital periods, with particular focus on intervals away from standstill. During these times, most of the systems display a sawtooth-like outburst behavior, with quiescent intervals comparable to the outburst durations. We report the discovery of a linear relation between the characteristic outburst period and orbital period for these systems, which is given by
ERIC Educational Resources Information Center
Merz, Eva-Maria; Schuengel, Carlo; Schulze, Hans-Joachim
2009-01-01
Purpose: Providing support to an aging parent may pose challenges to adult children but also provide an opportunity to "give back" to loved ones. The current study investigated changes in emotional and instrumental support and quality across a period of 4 years. Additionally, associations between intergenerational support and well-being in adult…
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. PMID:25711527
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
Identification of periods of clear sky irradiance in time series of GHI measurements
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
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.
People's preference patterns for gains/losses in multiple time period situations.
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. PMID:24597454
Adaptive time-delayed stabilization of steady states and periodic orbits.
Selivanov, Anton; Lehnert, Judith; Fradkov, Alexander; Schöll, Eckehard
2015-01-01
We derive adaptive time-delayed feedback controllers that stabilize fixed points and periodic orbits. First, we develop an adaptive controller for stabilization of a steady state by applying the speed-gradient method to an appropriate goal function and prove global asymptotic stability of the resulting system. For an example we show that the advantage of the adaptive controller over the nonadaptive one is in a smaller controller gain. Second, we propose adaptive time-delayed algorithms for stabilization of periodic orbits. Their efficiency is confirmed by local stability analysis. Numerical examples demonstrate the applicability of the proposed controllers. PMID:25679681
A Time-Delayed Mathematical Model for Tumor Growth with the Effect of a Periodic Therapy
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. PMID:27274763
Adaptive time-delayed stabilization of steady states and periodic orbits
NASA Astrophysics Data System (ADS)
Selivanov, Anton; Lehnert, Judith; Fradkov, Alexander; Schöll, Eckehard
2015-01-01
We derive adaptive time-delayed feedback controllers that stabilize fixed points and periodic orbits. First, we develop an adaptive controller for stabilization of a steady state by applying the speed-gradient method to an appropriate goal function and prove global asymptotic stability of the resulting system. For an example we show that the advantage of the adaptive controller over the nonadaptive one is in a smaller controller gain. Second, we propose adaptive time-delayed algorithms for stabilization of periodic orbits. Their efficiency is confirmed by local stability analysis. Numerical examples demonstrate the applicability of the proposed controllers.
A Time-Delayed Mathematical Model for Tumor Growth with the Effect of a Periodic Therapy.
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. PMID:27274763
Mandel, Tobey; Dunkley, David M; Moroz, Molly
2015-10-01
This study of 150 community adults examined heightened emotional reactivity to daily stress as a mediator in the relationships between self-critical (SC) perfectionism and depressive and anxious symptoms over a period of 4 years. Participants completed questionnaires assessing: perfectionism dimensions, general depressive symptoms (i.e., shared with anxiety), specific depressive symptoms (i.e., anhedonia), general anxious symptoms (i.e., shared with depression), and specific anxious symptoms (i.e., somatic anxious arousal) at Time 1; daily stress and affect (e.g., sadness, negative affect) for 14 consecutive days at Month 6 and Year 3; and depressive and anxious symptoms at Year 4. Path analyses indicated that SC perfectionism predicted daily stress-sadness reactivity (i.e., greater increases in sadness in response to increases in stress) across Month 6 and Year 3, which in turn explained why individuals with higher SC perfectionism had more general depressive symptoms, anhedonic depressive symptoms, and general anxious symptoms, respectively, 4 years later. In contrast, daily reactivity to stress with negative affect did not mediate the prospective relation between SC perfectionism and anhedonic depressive symptoms. Findings also demonstrated that higher mean levels of daily stress did not mediate the relationship between SC perfectionism and depressive and anxious symptoms 4 years later. These findings highlight the importance of targeting enduring heightened stress reactivity in order to reduce SC perfectionists' vulnerability to depressive and anxious symptoms over the long term. PMID:26191980
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. PMID:25730265
Skolski, J. Z. P. Vincenc Obona, J.; Römer, G. R. B. E.; Huis in 't Veld, A. J.
2014-03-14
A model predicting the formation of laser-induced periodic surface structures (LIPSSs) is presented. That is, the finite-difference time domain method is used to study the interaction of electromagnetic fields with rough surfaces. In this approach, the rough surface is modified by “ablation after each laser pulse,” according to the absorbed energy profile, in order to account for inter-pulse feedback mechanisms. LIPSSs with a periodicity significantly smaller than the laser wavelength are found to “grow” either parallel or orthogonal to the laser polarization. The change in orientation and periodicity follow from the model. LIPSSs with a periodicity larger than the wavelength of the laser radiation and complex superimposed LIPSS patterns are also predicted by the model.
Natural convection in an enclosure under time periodic heating: An experimental study
Antohe, B.V.; Lage, J.L.
1996-12-31
The effect of the heating period on the heat transfer across a water filled rectangular enclosure is examined experimentally. The enclosure is designed such that periodic heat by Joule effect is delivered at one wall while the opposite wall is maintained at an approximately constant temperature. All other surfaces are insulated. Several heating power levels are chosen with equivalent time averaged heat-flux based Rayleigh number varying from 2.5 {times} 10{sup 8} to 1.0 {times} 10{sup 9}. The heating period varies from 32 seconds to 1600 seconds. For the highest Rayleigh number, Ra = 1.0 {times} 10{sup 9}, the oscillatory heating process leads to a cycle averaged heat transfer coefficient 20 percent higher than obtained with steady averaged-heat flux heating. Results, presented in terms of temperature time series, phase-plane portrait, and time evolution of cooling and heating wall temperatures, indicate that for low heating frequencies the heat transfer across the enclosure is hindered, with the time averaged heat transfer coefficient decreasing by as much as 13 percent of the equivalent steady heating value. A plausible explanation for the phenomenon is offered and discussed. The instantaneous and cycle averaged heat transfer coefficients, and the corresponding Nusselt numbers, are also presented for various heating frequencies.
NASA Astrophysics Data System (ADS)
Grigor'ev, G. I.; Bakhmet'eva, N. V.; Tolmacheva, A. V.; Kalinina, E. E.
2013-09-01
We consider diffusion of the ionospheric-plasma irregularities as applied to the problem of experimental determination of the lower-ionosphere parameters by artificial periodic irregularities of the electron number density. A rigorous solution to the problem of diffusion of one-dimensional plasma irregularities in a weakly ionized medium, whose diffusion coefficient exponentially decreases with the altitude, is obtained. The Green's function for this problem is found. Three parameters are taken into account in the solution, namely, the size of the region occupied by the irregularities, the size of the irregularities, and a typical spatial scale of the e-fold decrease in the diffusion coefficient. Theoretical relaxation times of the irregularities as functions of these parameters are analyzed. Calculated relaxation times are compared with the times measured in the observation of the artificial periodic irregularities created by the SURA facility. Calculated relaxation times of these irregularities are in good agreement with the observed values.
A Gaussian Process Based Online Change Detection Algorithm for Monitoring Periodic Time Series
Chandola, Varun; Vatsavai, Raju
2011-01-01
Online time series change detection is a critical component of many monitoring systems, such as space and air-borne remote sensing instruments, cardiac monitors, and network traffic profilers, which continuously analyze observations recorded by sensors. Data collected by such sensors typically has a periodic (seasonal) component. Most existing time series change detection methods are not directly applicable to handle such data, either because they are not designed to handle periodic time series or because they cannot operate in an online mode. We propose an online change detection algorithm which can handle periodic time series. The algorithm uses a Gaussian process based non-parametric time series prediction model and monitors the difference between the predictions and actual observations within a statistically principled control chart framework to identify changes. A key challenge in using Gaussian process in an online mode is the need to solve a large system of equations involving the associated covariance matrix which grows with every time step. The proposed algorithm exploits the special structure of the covariance matrix and can analyze a time series of length T in O(T^2) time while maintaining a O(T) memory footprint, compared to O(T^4) time and O(T^2) memory requirement of standard matrix manipulation methods. We experimentally demonstrate the superiority of the proposed algorithm over several existing time series change detection algorithms on a set of synthetic and real time series. Finally, we illustrate the effectiveness of the proposed algorithm for identifying land use land cover changes using Normalized Difference Vegetation Index (NDVI) data collected for an agricultural region in Iowa state, USA. Our algorithm is able to detect different types of changes in a NDVI validation data set (with ~80% accuracy) which occur due to crop type changes as well as disruptive changes (e.g., natural disasters).
Thinking inside the Block Schedule: Strategies for Teaching in Extended Periods of Time.
ERIC Educational Resources Information Center
Robbins, Pam; Gregory, Gayle; Herndon, Lynne E.
This book provides an array of strategies that can help teachers, administrators, and staff-development personnel as they plan, develop, and deliver content within extended periods of instructional time. It emphasizes the importance of teachers and administrators working together to improve instruction and contends that staff development remains…
20 CFR 261.10 - Increase in future benefits where time period for reopening has expired.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Increase in future benefits where time period for reopening has expired. 261.10 Section 261.10 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT ADMINISTRATIVE FINALITY § 261.10 Increase in future...
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... contract or agreement where food safety or animal welfare is concerned. These criteria, include, but...
9 CFR 201.217 - Reasonable period of time to remedy a breach of contract.
Code of Federal Regulations, 2013 CFR
2013-01-01
... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Reasonable period of time to remedy a breach of contract. 201.217 Section 201.217 Animals and Animal Products GRAIN INSPECTION, PACKERS AND... contract or agreement where food safety or animal welfare is concerned. These criteria, include, but...
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... contract or agreement where food safety or animal welfare is concerned. These criteria, include, but...
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…
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. PMID:24369452
ERIC Educational Resources Information Center
Ramaprasad, Jyotika; Ong, James
In order to identify the scope or limits of the practice of development journalism, a study examined the content of the Forum page in the "Straits Times" of Singapore during relatively free (1979-1980) and restricted (1986-1987) press periods. The study had two major objectives: (1) to study the nature of the Forum page (a readers' letter page in…
41 CFR 105-8.150-3 - Time period for compliance.
Code of Federal Regulations, 2014 CFR
2014-01-01
... 41 Public Contracts and Property Management 3 2014-01-01 2014-01-01 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...
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...
41 CFR 105-8.150-3 - Time period for compliance.
Code of Federal Regulations, 2012 CFR
2012-01-01
... 41 Public Contracts and Property Management 3 2012-01-01 2012-01-01 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...
41 CFR 105-8.150-3 - Time period for compliance.
Code of Federal Regulations, 2013 CFR
2013-07-01
... 41 Public Contracts and Property Management 3 2013-07-01 2013-07-01 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...
20 CFR 261.10 - Increase in future benefits where time period for reopening has expired.
Code of Federal Regulations, 2012 CFR
2012-04-01
... 20 Employees' Benefits 1 2012-04-01 2012-04-01 false Increase in future benefits where time period for reopening has expired. 261.10 Section 261.10 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT ADMINISTRATIVE FINALITY § 261.10 Increase in future...
Determination of the Conservation Time of Periodicals for Optimal Shelf Maintenance of a Library.
ERIC Educational Resources Information Center
Miyamoto, Sadaaki; Nakayama, Kazuhiko
1981-01-01
Presents a method based on a constrained optimization technique that determines the time of removal of scientific periodicals from the shelf of a library. A geometrical interpretation of the theoretical result is given, and a numerical example illustrates how the technique is applicable to real bibliographic data. (FM)
45 CFR 96.14 - Time period for obligation and expenditure of grant funds.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 45 Public Welfare 1 2011-10-01 2011-10-01 false Time period for obligation and expenditure of grant funds. 96.14 Section 96.14 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL... first allotted shall remain available for obligation during the succeeding fiscal year for all...
45 CFR 96.14 - Time period for obligation and expenditure of grant funds.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 45 Public Welfare 1 2010-10-01 2010-10-01 false Time period for obligation and expenditure of grant funds. 96.14 Section 96.14 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL... first allotted shall remain available for obligation during the succeeding fiscal year for all...
42 CFR 87.7 - For what period of time will grants be awarded?
Code of Federal Regulations, 2013 CFR
2013-10-01
... 42 Public Health 1 2013-10-01 2013-10-01 false For what period of time will grants be awarded? 87.7 Section 87.7 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES NATIONAL INSTITUTE FOR OCCUPATIONAL SAFETY...
42 CFR 87.7 - For what period of time will grants be awarded?
Code of Federal Regulations, 2012 CFR
2012-10-01
... 42 Public Health 1 2012-10-01 2012-10-01 false For what period of time will grants be awarded? 87.7 Section 87.7 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES NATIONAL INSTITUTE FOR OCCUPATIONAL SAFETY...
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…
45 CFR 96.14 - Time period for obligation and expenditure of grant funds.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 45 Public Welfare 1 2012-10-01 2012-10-01 false Time period for obligation and expenditure of grant funds. 96.14 Section 96.14 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL... first allotted shall remain available for obligation during the succeeding fiscal year for all...
A Comparison of Terminally Ill Persons at Various Time Periods to Death.
ERIC Educational Resources Information Center
Baugher, Robert J.; And Others
1990-01-01
Examined responses of 1,110 terminally ill persons with cancer at varying time periods prior to death. Disengagement and Objective Self-Awareness theories, which suggest that people nearing death would increase desire to separate from others, were not supported. Found few differences in responses of persons further from, or closer to, death.…
42 CFR 87.7 - For what period of time will grants be awarded?
Code of Federal Regulations, 2011 CFR
2011-10-01
... OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES NATIONAL INSTITUTE FOR OCCUPATIONAL SAFETY AND... awards will be of such factors as the grantee's progress and management practices, and the availability... 42 Public Health 1 2011-10-01 2011-10-01 false For what period of time will grants be awarded?...
Practitioners' Perceptions of the Soccer Extra-Time Period: Implications for Future Research.
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
Time Periods of Unusual Density Behavior Observed by GRACE and CHAMP
NASA Astrophysics Data System (ADS)
McLaughlin, C. A.; Fattig, E.; Mysore Krishna, D.; Locke, T.; Mehta, P. M.
2011-12-01
Time periods of low cross correlation between precision orbit ephemeris (POE) derived density and accelerometer density for CHAMP and GRACE are examined. In particular, the cross correlation for GRACE dropped from typical values near 0.9 to much lower values and then returned to typical over the time period of late October to late December of 2005. This time period includes a maneuver where GRACE-A and GRACE-B swapped positions. However, the drop in cross correlation begins and reaches its low point before the maneuvers begin. In addition, the densities were found using GRACE-A, but GRACE-B did most of the maneuvering. The time period is characterized by high frequency variations in accelerometer density of the same magnitude as the daylight to eclipse variations over the course of an orbit. However, the daylight to eclipse variations are particularly small during this time period because the orbit plane is near the terminator. Additionally, the difference between the accelerometer and POE derived densities are not unusually large during this time period. This implies the variations are not unusual, just more significant when the orbit plane is near terminator. Cyclical variations in correlation of the POE derived densities with accelerometer derived densities are seen for both GRACE and CHAMP, but the magnitude of the variations are much larger for GRACE, possibly because of the higher altitude of GRACE. The cycles seem to be phased so that low correlations occur with low beta angle when the orbit plane is near the terminator. The low correlation is possibly caused by the lower amplitude of the daylight to eclipse signal making higher frequency variations relatively more important. However, another possible explanation is terminator waves in density that propagate to the thermosphere from lower in the atmosphere. These waves have been observed in CHAMP accelerometer data and global circulation model simulations. Further investigation is needed to see if the
NASA Astrophysics Data System (ADS)
Tiwary, A.; Arya, R.; Choube, S. C.; Arya, L. D.
2012-06-01
This paper describes a technique for determination of optimum duration between inspections for each distributor segment of a distribution system. The optimum period between inspections is decided based on maximization of availability of the distribution system. The view point presented is that after inspection a minor maintenance is carried out which may otherwise cause failure of the system in future, for example, trimming of tree branches, arcing and damages of jumper connections and to avoid breakdown of insulators. Such stray causes may have small failure rates in total but periodic inspection and maintenance will increase the availability. Exponential failure law has been assumed. Inspection time and repair time, if required after inspection, have been assumed to be normally distributed. Two-membered evolution strategy has been used for optimization. The algorithm has been implemented on a sample radial distribution system.
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
Time-space Variability of Weekly to Monthly Period Equatorial Waves in the Pacific Ocean
NASA Astrophysics Data System (ADS)
Durland, T.; Farrar, J. T.
2015-12-01
Data from satellite altimetry are used to characterize wavelike variability in the tropical Pacific Ocean at periods of days to two months. This period band is of interest because the space-time scales of oceanic equatorial waves at these frequencies have historically made adequate observation of the variability difficult. These waves have zonal scales that are very large (exceeding 3000 km) and meridional scales that are relatively short (~100 km), making in situ measurements difficult, and the short temporal scales pose challenges for observation with satellite altimeters because the wave periods are short compared to orbit repeat periods. As a result, there has been relatively little progress since the early 1980s in characterizing and understanding these equatorial inertia-gravity and mixed Rossby-gravity waves. In this analysis, we seek to exploit the long zonal length scales of these high-frequency equatorial waves in an analysis of satellite scatterometer and altimeter data to shed new light on the properties and dynamics of these waves. At periods of 2-14 days, there is clear evidence for the presence of several basin-scale equatorial wave modes, including mixed Rossby-gravity waves and inertia-gravity waves associated with baroclinic modes one and two. Here, we focus on equatorial Kelvin waves and mixed Rossby-gravity waves forced in the western Pacific, and examine their variability in time and space and their relation to wind.
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.
The Varying Light Curve and Timings of the Ultrashort-period Contact Binary KIC 9532219
NASA Astrophysics Data System (ADS)
Lee, Jae Woo; Hong, Kyeongsoo; Koo, Jae-Rim; Park, Jang-Ho
2016-03-01
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 T1-T2 = 172 K, and a third light of l3 = 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⊙ 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.
Estimating the incubation period of raccoon rabies: a time-space clustering approach.
Tinline, Rowland; Rosatte, Rick; MacInnes, Charles
2002-11-29
We used a time-space clustering approach to estimate the incubation period of raccoon rabies in the wild using data from the 1999-2001 invasion of raccoon rabies into eastern Ontario from northern New York State. The time differences and geographical distances between all possible pairs of rabies cases were computed, classified and assembled into a time-space matrix. The rows of that matrix represented differences in cases in weeks and the columns represent distances between cases in kilometers and the values in the cells of the matrix represent the counts of cases at specific time and distance intervals. There was a significant cluster of pairs 5 weeks apart with apparent harmonics at additional 5-week intervals. These results are explained by assuming the incubation period of raccoon rabies had a mode of 5 weeks. The time clusters appeared consistently at distance intervals of 5 km. We discuss the possibility that the spatial intervals were influenced by the 5 km radius of the point infection control depopulation process used in 1999 and the 10-15 km radial areas used in 2000. With the practical limits of those radii, there was an intensive effort to eliminate raccoons. Our procedure is easy to implement and provides an estimate of the shape of the distribution of incubation periods for raccoon rabies. PMID:12419602
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.
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.
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.
Sex difference in the near-24-hour intrinsic period of the human circadian timing system
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
A General Approach to Time Periodic Incompressible Viscous Fluid Flow Problems
NASA Astrophysics Data System (ADS)
Geissert, Matthias; Hieber, Matthias; Nguyen, Thieu Huy
2016-06-01
This article develops a general approach to time periodic incompressible fluid flow problems and semilinear evolution equations. It yields, on the one hand, a unified approach to various classical problems in incompressible fluid flow and, on the other hand, gives new results for periodic solutions to the Navier-Stokes-Oseen flow, the Navier-Stokes flow past rotating obstacles, and, in the geophysical setting, for Ornstein-Uhlenbeck and various diffusion equations with rough coefficients. The method is based on a combination of interpolation and topological arguments, as well as on the smoothing properties of the linearized equation.
Time Periodic Solutions to the One-Dimensional Nonlinear Wave Equation
NASA Astrophysics Data System (ADS)
Ji, Shuguan; Li, Yong
2011-02-01
This paper is concerned with the time periodic solutions to the one-dimensional nonlinear wave equation with either variable or constant coefficients. By adjusting the basis of L 2 function space, we can circumvent the difficulties caused by η u = 0 and obtain the existence of a weak periodic solution, which was posed as an open problem by Baubu and Pavel in (Trans Am Math Soc 349:2035-2048, 1997). Finally, an application to the forced Sine-Gordon equation is presented to illustrate the utility of this technique.
Plasticity of the Intrinsic Period of the Human Circadian Timing System
Scheer, Frank A.J.L.; Wright, Kenneth P.; Kronauer, Richard E.; Czeisler, Charles A.
2007-01-01
Human expeditions to Mars will require adaptation to the 24.65-h Martian solar day-night cycle (sol), which is outside the range of entrainment of the human circadian pacemaker under lighting intensities to which astronauts are typically exposed. Failure to entrain the circadian time-keeping system to the desired rest-activity cycle disturbs sleep and impairs cognitive function. Furthermore, differences between the intrinsic circadian period and Earth's 24-h light-dark cycle underlie human circadian rhythm sleep disorders, such as advanced sleep phase disorder and non-24-hour sleep-wake disorders. Therefore, first, we tested whether exposure to a model-based lighting regimen would entrain the human circadian pacemaker at a normal phase angle to the 24.65-h Martian sol and to the 23.5-h day length often required of astronauts during short duration space exploration. Second, we tested here whether such prior entrainment to non-24-h light-dark cycles would lead to subsequent modification of the intrinsic period of the human circadian timing system. Here we show that exposure to moderately bright light (∼450 lux; ∼1.2 W/m2) for the second or first half of the scheduled wake episode is effective for entraining individuals to the 24.65-h Martian sol and a 23.5-h day length, respectively. Estimations of the circadian periods of plasma melatonin, plasma cortisol, and core body temperature rhythms collected under forced desynchrony protocols revealed that the intrinsic circadian period of the human circadian pacemaker was significantly longer following entrainment to the Martian sol as compared to following entrainment to the 23.5-h day. The latter finding of after-effects of entrainment reveals for the first time plasticity of the period of the human circadian timing system. Both findings have important implications for the treatment of circadian rhythm sleep disorders and human space exploration. PMID:17684566
The Passive in 3- and 4-Year-Olds
ERIC Educational Resources Information Center
de Barros Pereira Rubin, Maraci Coelho
2009-01-01
This paper argues that analyzing the patterns of individual subject performance in tests of comprehension of passives might give insight into how little children interpret passives: 3 and 4 year-olds seem to go through a range of passive interpretation, that varies from actual comprehension to total non-comprehension. The fact that some small…
20 CFR 210.4 - Year of service.
Code of Federal Regulations, 2011 CFR
2011-04-01
... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Year of service. 210.4 Section 210.4... RAILROAD SERVICE § 210.4 Year of service. (a) A year of service is twelve months of reported or deemed service, consecutive or not consecutive. A fraction of a year of service is taken at its actual value....
20 CFR 210.4 - Year of service.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Year of service. 210.4 Section 210.4... RAILROAD SERVICE § 210.4 Year of service. (a) A year of service is twelve months of reported or deemed service, consecutive or not consecutive. A fraction of a year of service is taken at its actual value....
Head Start, 4 years After Completing the Program
ERIC Educational Resources Information Center
Kim, Young-Joo
2013-01-01
This paper studies the effect of the Head Start program on children's achievements in reading and math tests during their first 4 years of schooling after completing the program. Using nationally representative data from the Early Childhood Longitudinal Study, I found large measurement error in the parental reports of Head Start attendance,…
Grammatical Morpheme Production in 4-Year-Old Children.
ERIC Educational Resources Information Center
Balason, Denise V.; Dollaghan, Christine A.
2002-01-01
Grammatical morpheme (GM) production was studied in 15-minute spontaneous language samples from 100 4-year-olds. Substantial variability was observed in both the frequency of obligatory contexts and in the percentages of correct usage of GM. For only one morpheme did all 100 participants contain the minimum number of 3 obligatory contexts.…
The Effectiveness of Alcohol Policies in 4-Year Public Universities
ERIC Educational Resources Information Center
Walter, Gayle T.
2010-01-01
A problem facing American universities is heavy drinking by the student body which results in unintentional injuries and deaths, illegal offenses, sexual assault, altercations, and academic demise. The relationship between the type of alcohol policy enacted on campus and alcohol consumption among undergraduate students attending 4-year public…
20 CFR 210.4 - Year of service.
Code of Federal Regulations, 2013 CFR
2013-04-01
... 20 Employees' Benefits 1 2013-04-01 2012-04-01 true Year of service. 210.4 Section 210.4 Employees... SERVICE § 210.4 Year of service. (a) A year of service is twelve months of reported or deemed service, consecutive or not consecutive. A fraction of a year of service is taken at its actual value. (b) The...
20 CFR 210.4 - Year of service.
Code of Federal Regulations, 2014 CFR
2014-04-01
... 20 Employees' Benefits 1 2014-04-01 2012-04-01 true Year of service. 210.4 Section 210.4 Employees... SERVICE § 210.4 Year of service. (a) A year of service is twelve months of reported or deemed service, consecutive or not consecutive. A fraction of a year of service is taken at its actual value. (b) The...
Fecal Calprotectin in Healthy Children Aged 1-4 Years
Zhu, Qingling; Li, Feng; Wang, Junli; Shen, Lixiao; Sheng, Xiaoyang
2016-01-01
Objective Calprotectin has been well emulated recently in adults as well as in children. The aim of this study was to assess fecal calprotectin concentrations in healthy children aged from 1 to 4 years. Methods Volunteers were enlisted from 3 nurseries. A brief questionnaire was used to ensure these children meet the inclusion criteria, and some clinical and sociodemographic factors were collected. Anthro software (version 3.1) was used to calculated Length-for-age Z-scores (LAZ), weight-for-age Z-scores (WAZ), and weight-for-length Z-scores (WLZ) respectively. Fecal calprotectin was detected by a commercially available ELISA. Results In total 274 children were recruited, with age ranging from 1 to 4 years old. The median FC concentration was 83.19 μg/g [range 4.58 to 702.50 μg/g, interquartile range (IQR) 14.69–419.45 μg/g] or 1.92 log10 μg/g (range 0.66 log10 to 2.85 log10 μg/g, IQR 1.17 log10-2.62 log10 μg/g). All of the children were divided into three groups, 1–2 years (12–24 months), 2–3 years (24–36 months), 3–4 years (36–48 months), with median FC concentrations 96.14 μg/g (1.98 log10 μg/g), 81.48 μg/g (1.91 log10 μg/g), 65.36 μg/g (1.82 log10 μg/g), respectively. There was similar FC level between boys and girls. FC concentrations showed a downward trend by the growing age groups. A statistic difference was found in FC concentrations among groups 1–2 years, 2–3 years and 3–4 years (P = 0.016). In inter-groups comparison, a significant difference was found between children aged 1–2 years and children aged 3–4 years (P = 0.007). A negative correlation trend was found between age and FC concentration (Spearman's rho = -0.167, P = 0.005) in all the participants. A simple correlation was performed among WLZ, WAZ, birth weight, or birth length with FC, and there was no correlation being observed. Conclusion Children aged from 1 to 4 years old have lower FC concentrations compared with healthy infants (<1years), and higher FC
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
Stability and attractivity of periodic solutions of parabolic systems with time delays
NASA Astrophysics Data System (ADS)
Pao, C. V.
2005-04-01
This paper is concerned with the existence, stability, and global attractivity of time-periodic solutions for a class of coupled parabolic equations in a bounded domain. The problem under consideration includes coupled system of parabolic and ordinary differential equations, and time delays may appear in the nonlinear reaction functions. Our approach to the problem is by the method of upper and lower solutions and its associated monotone iterations. The existence of time-periodic solutions is for a class of locally Lipschitz continuous reaction functions without any quasimonotone requirement using Schauder fixed point theorem, while the stability and attractivity analysis is for quasimonotone nondecreasing and mixed quasimonotone reaction functions using the monotone iterative scheme. The results for the general system are applied to the standard parabolic equations without time delay and to the corresponding ordinary differential system. Applications are also given to three Lotka-Volterra reaction diffusion model problems, and in each problem a sufficient condition on the reaction rates is obtained to ensure the stability and global attractivity of positive periodic solutions.
Primate enamel evinces long period biological timing and regulation of life history.
Bromage, Timothy G; Hogg, Russell T; Lacruz, Rodrigo S; Hou, Chen
2012-07-21
The factor(s) regulating the combination of traits that define the overall life history matrix of mammalian species, comprising attributes such as brain and body weight, age at sexual maturity, lifespan and others, remains a complete mystery. The principal objectives of the present research are (1) to provide evidence for a key variable effecting life history integration and (2) to provide a model for how one would go about investigating the metabolic mechanisms responsible for this rhythm. We suggest here that a biological rhythm with a period greater than the circadian rhythm is responsible for observed variation in primate life history. Evidence for this rhythm derives from studies of tooth enamel formation. Enamel contains an enigmatic periodicity in its microstructure called the striae of Retzius, which develops at species specific intervals in units of whole days. We refer to this enamel rhythm as the repeat interval (RI). For primates, we identify statistically significant relationships between RI and all common life history traits. Importantly, RI also correlates with basal and specific metabolic rates. With the exception of estrous cyclicity, all relationships share a dependence upon body mass. This dependence on body mass informs us that some aspect of metabolism is responsible for periodic energy allocations at RI timescales, regulating cell proliferation rates and growth, thus controlling the pace, patterning, and co-variation of life history traits. Estrous cyclicity relates to the long period rhythm in a body mass-independent manner. The mass-dependency and -independency of life history relationships with RI periodicity align with hypothalamic-mediated neurosecretory anterior and posterior pituitary outputs. We term this period the Havers-Halberg Oscillation (HHO), in reference to Clopton Havers, a 17th Century hard tissue anatomist, and Franz Halberg, a long-time explorer of long-period rhythms. We propose a mathematical model that may help elucidate
NASA Astrophysics Data System (ADS)
Wang, Minshen
The primary interest of the electromagnetic behavior of a periodic structure is in its near field and far field. However, it is still numerically difficult to analyze either one in the time domain. The primary goal of this dissertation is to develop corresponding time domain technique to analyze two topics. The first one is to evaluate the far field of a realistic, large antenna array using an efficient method. The second one is to evaluate the propagation characteristic of a commercially available printed circuit board (PCB) with intentional roughness. Both of which are hot topics in the antenna and signal integrity (SI) society respectively; however, none of them have ever been solved in the time domain. To efficiently evaluate the far field pattern of a realistically large antenna array, the spectral domain method and the reciprocity theorem are implemented in the finite difference time domain (FDTD) technique to avoid the simulation of the near field. By taking advantage of the periodic boundary condition (PBC), the proposed method demonstrates its capability to speed up far field evaluation from hours to minutes. Good agreement of the results is provided for various cases: circular antenna array, arbitrary feeding array, and highly directional leaky wave antenna, etc. Periodic structure modeling with finite sized feedings is developed by the array scanning method (ASM) implemented in the FDTD technique. The minimally coupled electric and magnetic co-mingled antenna array is evaluated by the method. Moreover, a commercially available PCB with very small roughness is modeled by the ASM-FDTD and the propagation characteristic is evaluated. Both are evaluated by time domain method for the first time. Efficiency in terms of memory and computing time is shown for this method and parallelization in the future is proposed.
NASA Astrophysics Data System (ADS)
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.
Computation of symmetric, time-periodic solutions of the vortex sheet with surface tension
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
First-Passage and Residence Times in a Periodically Driven Integrate-and-Fire Model
NASA Astrophysics Data System (ADS)
Talkner, Peter; Schindler, Michael; Hänggi, Peter
2004-03-01
The stochastic integrate-and-fire model presents a simple description of the spiking behavior of neurons.In this model a neuron ``fires'' if an Ornstein-Uhlenbeck process crosses a prescribed threshold. After the firing the process is assumed to be in a refractory state, and from there it is put back into its initial, active state.This process can be characterized by the distribution of the first passage times of the threshold and by the residence times in the active states.We determined the distributions of these times for the integrate-and-fire model for short refractory times in the presence of a periodic signal.This is done by numerical solutions both of the respective Langevin equation and the equivalent Fokker-Planck equation. The results are compared with an approximate analytic theory. If the period of the signal is large compared to the relaxation time of the Ornstein-Uhlenbeck process and if the threshold is higher than a few times the noise strength we find theory and numerics to be in excellent agreement.
Tracing temperature in a nanometer size region in a picosecond time period.
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
Is the use of underwater polarized light by fish restricted to crepuscular time periods?
Novales Flamarique, I; Hawryshyn, C W
1997-04-01
We measured the spectral distributions of the underwater total and polarized light fields in the upper photic zone of meso-eutrophic waters (i.e., blue-green waters containing medium to high chlorophyll a concentrations). Per cent polarization levels during the day were always lower than 40%, but at crepuscular times these values could increase to 67%. A corresponding change occurred in the spectral distribution, with proportionately more shorter wavelength photons contributing to the total spectrum during crepuscular periods. Electrophysiological recordings from the optic nerve of rainbow trout subjected to light stimuli of varying polarization percentages show that the animal's threshold for detecting polarized light is between 63 and 72%. These physiological findings suggest that the use of water-induced polarized light cues by rainbow trout and similar percomorph fish should be restricted to crepuscular time periods. PMID:9196717