Science.gov

Sample records for 6-year time period

  1. 6-Year Periodicity and Variable Synchronicity in a Mass-Flowering Plant

    PubMed Central

    Kakishima, Satoshi; Yoshimura, Jin; Murata, Hiroko; Murata, Jin

    2011-01-01

    Periodical organisms, such as bamboos and periodical cicadas, are very famous for their synchronous reproduction. In bamboos and other periodical plants, the synchronicity of mass-flowering and withering has been often reported indicating these species are monocarpic (semelparous) species. Therefore, synchronicity and periodicity are often suspected to be fairly tightly coupled traits in these periodical plants. We investigate the periodicity and synchronicity of Strobilanthes flexicaulis, and a closely related species S. tashiroi on Okinawa Island, Japan. The genus Strobilanthes is known for several periodical species. Based on 32-year observational data, we confirmed that S. flexicaulis is 6-year periodical mass-flowering monocarpic plant. All the flowering plants had died after flowering. In contrast, we found that S. tashiroi is a polycarpic perennial with no mass-flowering from three-year individual tracking. We also surveyed six local populations of S. flexicaulis and found variation in the synchronicity from four highly synchronized populations (>98% of plants flowering in the mass year) to two less synchronized one with 11–47% of plants flowering before and after the mass year. This result might imply that synchrony may be selected for when periodicity is established in monocarpic species. We found the selective advantages for mass-flowering in pollinator activities and predator satiation. The current results suggest that the periodical S. flexicaulis might have evolved periodicity from a non-periodical close relative. The current report should become a key finding for understanding the evolution of periodical plants. PMID:22163279

  2. Subjects with Impaired Fasting Glucose: Evolution in a Period of 6 Years

    PubMed Central

    Leiva, E.; Mujica, V.; Orrego, R.; Wehinger, S.; Soto, A.; Icaza, G.; Vásquez, M.; Díaz, L.; Andrews, M.; Arredondo, M.

    2014-01-01

    Aim. To study the evolution of impaired fasting glucose (IFG), considering glucose and HbA1c levels and risk factors associated, in a period of 6 years. Methods. We studied 94 subjects with impaired fasting glucose (IFG) that were diagnosed in 2005 and followed up to 2012. Glucose and HbA1c levels were determined. A descriptive analysis of contingence charts was performed in order to study the evolution in the development of type-2 diabetes mellitus (T2DM). Results. Twenty-eight of ninety-four subjects became T2DM; 51/94 remained with IFG; and 20/94 presented normal fasting glucose. From the 28 diabetic subjects, 9 had already developed diabetes and were under treatment with oral hypoglycemic agents; 5 were diagnosed with plasma glucose < 126 mg/dL, but with HbA1c over 6.5%. In those who developed diabetes, 15/28 had a family history of T2DM in first relative degree. Also, diabetic subjects had a BMI significantly higher than nodiabetics (t test: P < 0.01). The individuals that in 2005 had the highest BMI are those who currently have diabetes. Conclusion. The IFG constitutes a condition of high risk of developing T2DM in a few years, especially over 110 mg/dL and in obesity patients. PMID:25215305

  3. Microbial diversity in a submarine carbonate edifice from the serpentinizing hydrothermal system of the Prony Bay (New Caledonia) over a 6-year period.

    PubMed

    Postec, Anne; Quéméneur, Marianne; Bes, Méline; Mei, Nan; Benaïssa, Fatma; Payri, Claude; Pelletier, Bernard; Monnin, Christophe; Guentas-Dombrowsky, Linda; Ollivier, Bernard; Gérard, Emmanuelle; Pisapia, Céline; Gérard, Martine; Ménez, Bénédicte; Erauso, Gaël

    2015-01-01

    Active carbonate chimneys from the shallow marine serpentinizing Prony Hydrothermal Field were sampled 3 times over a 6 years period at site ST09. Archaeal and bacterial communities composition was investigated using PCR-based methods (clone libraries, Denaturating Gel Gradient Electrophoresis, quantitative PCR) targeting 16S rRNA genes, methyl coenzyme M reductase A and dissimilatory sulfite reductase subunit B genes. Methanosarcinales (Euryarchaeota) and Thaumarchaea were the main archaeal members. The Methanosarcinales, also observed by epifluorescent microscopy and FISH, consisted of two phylotypes that were previously solely detected in two other serpentinitzing ecosystems (The Cedars and Lost City Hydrothermal Field). Surprisingly, members of the hyperthermophilic order Thermococcales were also found which may indicate the presence of a hot subsurface biosphere. The bacterial community mainly consisted of Firmicutes, Chloroflexi, Alpha-, Gamma-, Beta-, and Delta-proteobacteria and of the candidate division NPL-UPA2. Members of these taxa were consistently found each year and may therefore represent a stable core of the indigenous bacterial community of the PHF chimneys. Firmicutes isolates representing new bacterial taxa were obtained by cultivation under anaerobic conditions. Our study revealed diverse microbial communities in PHF ST09 related to methane and sulfur compounds that share common populations with other terrestrial or submarine serpentinizing ecosystems. PMID:26379636

  4. Microbial diversity in a submarine carbonate edifice from the serpentinizing hydrothermal system of the Prony Bay (New Caledonia) over a 6-year period

    PubMed Central

    Postec, Anne; Quéméneur, Marianne; Bes, Méline; Mei, Nan; Benaïssa, Fatma; Payri, Claude; Pelletier, Bernard; Monnin, Christophe; Guentas-Dombrowsky, Linda; Ollivier, Bernard; Gérard, Emmanuelle; Pisapia, Céline; Gérard, Martine; Ménez, Bénédicte; Erauso, Gaël

    2015-01-01

    Active carbonate chimneys from the shallow marine serpentinizing Prony Hydrothermal Field were sampled 3 times over a 6 years period at site ST09. Archaeal and bacterial communities composition was investigated using PCR-based methods (clone libraries, Denaturating Gel Gradient Electrophoresis, quantitative PCR) targeting 16S rRNA genes, methyl coenzyme M reductase A and dissimilatory sulfite reductase subunit B genes. Methanosarcinales (Euryarchaeota) and Thaumarchaea were the main archaeal members. The Methanosarcinales, also observed by epifluorescent microscopy and FISH, consisted of two phylotypes that were previously solely detected in two other serpentinitzing ecosystems (The Cedars and Lost City Hydrothermal Field). Surprisingly, members of the hyperthermophilic order Thermococcales were also found which may indicate the presence of a hot subsurface biosphere. The bacterial community mainly consisted of Firmicutes, Chloroflexi, Alpha-, Gamma-, Beta-, and Delta-proteobacteria and of the candidate division NPL-UPA2. Members of these taxa were consistently found each year and may therefore represent a stable core of the indigenous bacterial community of the PHF chimneys. Firmicutes isolates representing new bacterial taxa were obtained by cultivation under anaerobic conditions. Our study revealed diverse microbial communities in PHF ST09 related to methane and sulfur compounds that share common populations with other terrestrial or submarine serpentinizing ecosystems. PMID:26379636

  5. Clinico-epidemiological Profile of Snake Bites over 6-year Period from a Rural Secondary Care Centre of Northern India: A Descriptive Study.

    PubMed

    Mitra, Shubhanker; Agarwal, Abhinav; Shubhankar, B U; Masih, Sahil; Krothapalli, Viswajit; Lee, Brian Mark; Kuruvilla, Jeevan; Alex, Reginald

    2015-01-01

    Estimated deaths due to snake bites are more than 46,000 annually in India. Ninety-seven percent bites occur in rural areas. Data on snake bites from Jharkhand rural area are sparse. This study describes 6 years profile of snake bite patients from January, 2007 to December, 2012 at Nav Jivan Hospital in Palamu district, Jharkhand. PMID:26862265

  6. Clinico-epidemiological Profile of Snake Bites over 6-year Period from a Rural Secondary Care Centre of Northern India: A Descriptive Study

    PubMed Central

    Mitra, Shubhanker; Agarwal, Abhinav; Shubhankar, B. U.; Masih, Sahil; Krothapalli, Viswajit; Lee, Brian Mark; Kuruvilla, Jeevan; Alex, Reginald

    2015-01-01

    Estimated deaths due to snake bites are more than 46,000 annually in India. Ninety-seven percent bites occur in rural areas. Data on snake bites from Jharkhand rural area are sparse. This study describes 6 years profile of snake bite patients from January, 2007 to December, 2012 at Nav Jivan Hospital in Palamu district, Jharkhand. PMID:26862265

  7. 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).

  8. Does the duration and time of sleep increase the risk of allergic rhinitis? Results of the 6-year nationwide Korea youth risk behavior web-based survey.

    PubMed

    Kwon, Jeoung A; Lee, Minjee; Yoo, Ki-Bong; Park, Eun-Cheol

    2013-01-01

    Allergic rhinitis (AR) is the most common chronic disorder in the pediatric population. Although several studies have investigated the correlation between AR and sleep-related issues, the association between the duration and time of sleep and AR has not been analyzed in long-term national data. This study investigated the relationship between sleep time and duration and AR risk in middle- and high-school students (adolescents aged 12-18). We analyzed national data from the Korea Youth Risk Behavior Web-based Survey by the Korea Centers for Disease Control and Prevention from 2007-2012. The sample size was 274,480, with an average response rate of 96.2%. Multivariate logistic regression analyses were conducted to determine the relationship between sleep and AR risk. Furthermore, to determine the best-fitted model among independent variables such as sleep duration, sleep time, and the combination of sleep duration and sleep time, we used Akaike Information Criteria (AIC) to compare models. A total of 43,337 boys and 41,665 girls reported a diagnosis of AR at baseline. The odds ratio increased with age and with higher education and economic status of the parents. Further, students in mid-sized and large cities had stronger relationships to AR than those in small cities. In both genders, AR was associated with depression and suicidal ideation. In the analysis of sleep duration and sleep time, the odds ratio increased in both genders when sleep duration was <7 hours, and when the time of sleep was later than 24:00 hours. Our results indicate an association between sleep time and duration and AR. This study is the first to focus on the relationship between sleep duration and time and AR in national survey data collected over 6 years. PMID:24015253

  9. Child mortality in a West African population protected with insecticide-treated curtains for a period of up to 6 years.

    PubMed Central

    Diallo, D. A.; Cousens, S. N.; Cuzin-Ouattara, N.; Nebié, I.; Ilboudo-Sanogo, E.; Esposito, F.

    2004-01-01

    OBJECTIVES: To determine the impact of insecticide-treated curtains (ITC) on all-cause child mortality (6-59 months) over a period of six years. To determine whether initial reductions in child mortality following the implementation of ITC are sustained over the longer term or whether "delayed" mortality occurs. METHODS: A rural population of ca 100 000 living in an area with high, seasonal Plasmodium falciparum transmission was studied in Burkina Faso. Annual censuses were conducted from 1993 to 2000 to measure child mortality. ITC to cover doors, windows, and eaves were provided to half the population in 1994 with the remainder receiving ITC in 1996. Curtains were re-treated or, if necessary, replaced annually. FINDINGS: Over six years of implementation of ITC, no evidence of the shift in child mortality from younger to older children was observed. Estimates of the reduction in child mortality associated with ITC ranged from 19% to 24%. CONCLUSIONS: In our population there was no evidence to suggest that initial reduction in child mortality associated with the introduction of insecticide-treated materials was subsequently compromised by a shift in child mortality to older-aged children. Estimates of the impact of ITC on child mortality in this population range from 19% to 24%. PMID:15042229

  10. 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....

  11. 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....

  12. 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....

  13. 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....

  14. 24 CFR 58.21 - Time periods.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  15. 24 CFR 58.21 - Time periods.

    Code of Federal Regulations, 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...

  16. 24 CFR 58.21 - Time periods.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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

  17. 24 CFR 58.21 - Time periods.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

  18. 24 CFR 58.21 - Time periods.

    Code of Federal Regulations, 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...

  19. 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…

  20. 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.

  1. Pennsylvanian time scales and cycle periods

    SciTech Connect

    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.

  2. 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.

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

    PubMed

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

    2014-01-01

    This study aimed to assess the clinical performance of lithium disilicate restorations supported by natural teeth or implants. Eight hundred sixty lithium disilicate adhesive restorations, including crowns on natural teeth and implant abutments, veneers, and onlays, were made in 312 patients. Parafunctional patients were included, but subjects with uncontrolled periodontitis and gingival inflammation were excluded. Veneers up to 0.5 mm thick were luted with flowable composite resin or light curing cements, while dual-curing composite systems were used with veneers up to 0.8 mm thick. Onlays up to 2 mm in thickness were luted with flowable composite resins or dual-curing composite cements. Crowns up to 1 mm in thickness were cemented with self-adhesive or dual-curing resin cements. The observational period ranged from 12 to 72 months, with a mean follow-up of 3 years. The mechanical and esthetic outcomes of the restorations were evaluated according to the modified California Dental Association (CDA) criteria. Data were analyzed with descriptive statistics. Twenty-six mechanical complications were observed: 17 porcelain chippings, 5 fractures, and 4 losses of retention. Structural drawbacks occurred mainly in posterior segments, and monolithic restorations showed the lowest number of mechanical complications. The clinical ratings of the successful restorations, both monolithic and layered, were satisfactory according to the modified CDA criteria for color match, porcelain surface, and marginal integrity. The cumulative survival rates of lithium disilicate restorations ranged from 95.46% to 100%, while cumulative success rates ranged from 95.39% to 100%. All restorations recorded very high survival and success rates. The use of lithium disilicate restorations in fixed prosthodontics proved to be effective and reliable in the short- and medium-term. PMID:24600653

  4. 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.

  5. 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...

  6. 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. 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...

  8. 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...

  9. 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...

  10. On almost periodic solutions of logistic delay differential equations with almost periodic time dependence

    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].

  11. 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.

  12. 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...

  13. 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…

  14. 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...

  15. 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...

  16. 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...

  17. EHRA research network surveys: 6 years of EP wires activity.

    PubMed

    Bongiorni, Maria Grazia; Chen, Jian; Dagres, Nikolaos; Estner, Heidi; Hernandez-Madrid, Antonio; Hocini, Meleze; Larsen, Torben Bjerregaard; Pison, Laurent; Potpara, Tatjana; Proclemer, Alessandro; Sciaraffia, Elena; Todd, Derick; Blomstrom-Lundqvist, Carina

    2015-11-01

    Clinical practice should follow guidelines and recommendations mainly based on the results of controlled trials, which are often conducted in selected populations and special conditions, whereas clinical practice may be influenced by factors different from controlled scientific studies. Hence, the real-world setting is better assessed by the observational registries enrolling patients for longer periods of time. However, this may be difficult, expensive, and time-consuming. In 2009, the Scientific Initiatives Committee of the European Heart Rhythm Association (EHRA) has instigated a series of surveys covering the controversial issues in clinical electrophysiology (EP). With this in mind, an EHRA EP research network has been created, which included EP centres in Europe among which the surveys on 'hot topic' were circulated. This review summarizes the overall experience conducting EP wires over the past 6 years, categorizing and assessing the topics regarding clinical EP, and evaluating the acceptance and feedback from the responding centres, in order to improve participation in the surveys and better address the research needs and aspirations of the European EP community. PMID:26589904

  18. 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

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 19 CFR 158.21a - Time period.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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

  4. 19 CFR 158.21a - Time period.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  5. 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)...

  6. 43 CFR 45.3 - How are time periods computed?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  7. 43 CFR 45.3 - How are time periods computed?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

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

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

    Code of Federal Regulations, 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)...

  9. 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)...

  10. 19 CFR 158.21a - Time period.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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

  11. 19 CFR 158.21a - Time period.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

  12. 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.

  13. 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.

  14. Bioplastique at 6 years: clinical outcome studies.

    PubMed

    Ersek, R A; Gregory, S R; Salisbury, A V

    1997-11-01

    Bioplastique is a biphasic polymer for the permanent augmentation of some soft tissues. It was developed in 1987, and clinical studies at this institution were begun in 1990. The combination of low molecular weight polyvinylpyrrolidone and solid polymer particles allows the implantation of permanent polymer spheres through a small needle under local anesthesia. In this study 127 cases are reviewed of consecutive patients who have received Bioplastique for scar revision, wrinkles, and augmentation for soft-tissue defects at 6 years after application. All patients who had not been in for follow-up recently were contacted by mail and questioned on the permanence of augmentation and migration of particles. About 30 percent of the patients were unreachable and had their charts reviewed for permanence and migration of particles. In eight of these cases, Bioplastique was removed because of overcorrection, two of them may have had infection. Bioplastique has gained wide use throughout the world and although some complications have been reported, in general, it functions quite well when used in selected cases. PMID:9385974

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

    PubMed

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

    2014-04-01

    We solve for the motion of charged particles in a helical time-periodic ABC (Arnold-Beltrami-Childress) magnetic field. The magnetic field lines of a stationary ABC field with coefficients A=B=C=1 are chaotic, and we show that the motion of a charged particle in such a field is also chaotic at late times with positive Lyapunov exponent. We further show that in time-periodic ABC fields, the kinetic energy of a charged particle can increase indefinitely with time. At late times the mean kinetic energy grows as a power law in time with an exponent that approaches unity. For an initial distribution of particles, whose kinetic energy is uniformly distributed within some interval, the probability density function of kinetic energy is, at late times, close to a Gaussian but with steeper tails. PMID:24827325

  16. 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.

  17. 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.

  18. Optimal health insurance for multiple goods and time periods.

    PubMed

    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

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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…

  7. 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.

  8. 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 §...

  9. 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.

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

    SciTech Connect

    Ambrose , D.M.; Wilkening, Jon

    2008-04-01

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

  11. Periodicity detection method for small-sample time series datasets.

    PubMed

    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

  12. 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.

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

    PubMed Central

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

    2016-01-01

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

  14. 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.

  15. 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.

  16. Krylov-subspace acceleration of time periodic waveform relaxation

    SciTech Connect

    Lumsdaine, A.

    1994-12-31

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

  17. 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.

  18. 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.

  19. 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.

  20. (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.

  1. Evidence for 18.6 year Mn signal in temperature and drought conditions in North America since AD 1800

    NASA Technical Reports Server (NTRS)

    Currie, R. G.

    1981-01-01

    It is found that, since 1800, the mean discrepancy in epoch between maxima in temperature and maxima in the Drought Area Index (DAI) for the western United States with respect to maxima in the lunar modal tide is 0.9 and 0.1 year, respectively. It is suggested, in light of the fact that a cluster of nine stations in western Canada yields the 18.6-year lunar nodal term out of phase with 30 stations in eastern North America, that (1) enhanced drought conditions in the western United States are neither recurrent nor rhythmic on a time scale of 20 years, but rather periodic with a period of 18.6 years, and (2) the Rocky Mountain system is an influence for atmospheric tidal phenomena at epochs of maximum in the lunar nodal tide as well as for maxima in the temperature records of the DAI.

  2. 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.

  3. Blood Lead Levels Among Children Aged <6 Years - Flint, Michigan, 2013-2016.

    PubMed

    Kennedy, Chinaro; Yard, Ellen; Dignam, Timothy; Buchanan, Sharunda; Condon, Suzanne; Brown, Mary Jean; Raymond, Jaime; Rogers, Helen Schurz; Sarisky, John; de Castro, Rey; Arias, Ileana; Breysse, Patrick

    2016-01-01

    During April 25, 2014-October 15, 2015, approximately 99,000 residents of Flint, Michigan, were affected by changes in drinking water quality after their water source was switched from the Detroit Water Authority (DWA), sourced from Lake Huron, to the Flint Water System (FWS), sourced from the Flint River.* Because corrosion control was not used at the FWS water treatment plant, the levels of lead in Flint tap water increased over time. Adverse health effects are associated with lead exposure (1). On January 2, 2015, a water advisory was issued because of detection of high levels of trihalomethanes, byproducts of disinfectants.(†)(,)(§) Studies conducted by local and national investigators detected an increase in the prevalence of blood lead levels (BLLs) ≥5 µg/dL (the CDC reference level) among children aged <5 years living in Flint (2) and an increase in water lead levels after the water source switch (3). On October 16, 2015, the Flint water source was switched back to DWA, and residents were instructed to use filtered tap water for cooking and drinking. During that time, pregnant and breastfeeding women and children aged <6 years were advised to consume bottled water.(¶) To assess the impact on BLLs of consuming contaminated drinking water, CDC examined the distribution of BLLs ≥5 µg/dL among children aged <6 years before, during, and after the switch in water source. This analysis enabled determination of whether the odds of having BLLs ≥5 µg/dL before the switch differed from the odds during the switch to FWS (before and after the January 2, 2015, water advisory was issued), and after the switch back to DWA. Overall, among 9,422 blood lead tests in children aged <6 years, 284 (3.0%) BLLs were ≥5 µg/dL during April 25, 2013-March 16, 2016. The adjusted probability of having BLLs ≥5 µg/dL was 46% higher during the period after the switch from DWA to FWS (and before the January 2, 2015, water advisory) than during the period before the

  4. 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.

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

    PubMed

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

    2009-01-01

    This study investigated the desensitization to violence over a short period of time. Participants watched nine violent movie scenes and nine comedy scenes, and reported whether they enjoyed the violent or comedy scenes and whether they felt sympathetic toward the victim of violence. Using latent growth modeling, analyses were carried out to investigate how participants responded to the different scenes across time. The findings of this study suggested that repeated exposure to media violence reduces the psychological impact of media violence in the short term, therefore desensitizing viewers to media violence. As a result, viewers tended to feel less sympathetic toward the victims of violence and actually enjoy more the violence portrayed in the media. Additionally, desensitization to media violence was better represented by a curvilinear pattern, whereas desensitization to comedy scenes was better represented by a linear pattern. Finally, trait aggression was not related to the pattern of change over time, although significant effects were found for initial reports of enjoyment and sympathy. PMID:19172659

  6. 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.

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

    NASA Astrophysics Data System (ADS)

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

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

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. High-latitude oceanic variability associated with the 18. 6-year nodal tide

    SciTech Connect

    Royer, T.C. )

    1993-03-15

    Ocean temperatures in the upper 250 m in the northern North Pacific (60[degree]N, 149[degree]W) increased by more than 1[degree]C from 1972 to 1986 but are now decreasing. Subsurface temperature anomalies are well correlated ([approx] 0.58) with the air temperature anomalies at Sitka, Alaska; hence the coastal air temperatures can be used as a proxy data set to extend the ocean temperature time series back to 1828. Up to 30% of the low-frequency variance can be accounted for with the 18.6-year nodal signal. Additionally, spectral analysis of these air temperature variations indicates a significant low-frequency peak in the range of the 18.6-year signal. Similar low-frequency signals have been reported for Hudson Bay air temperatures since 1700, for sea surface temperatures in the North Atlantic from 1876 to 1939, and for sea level in the high-latitude southern hemisphere. The water column temperature variations presented here are the first evidence that the upper ocean is responding to this very long period tidal forcing. An enhanced high-latitude response to the 18.6-year forcing is predicted by equilibrium tide theory, and it should be most evident at latitudes poleward of about 50[degree]. These low-frequency ocean-atmosphere variations must be considered in high-latitude assessments of global climate change, since they are of the same magnitude as many of the predicted global changes. 29 refs., 5 figs., 2 tabs.

  15. Almost periodic dynamics for impulsive delay neural networks of a general type on almost periodic time scales

    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.

  16. A Gunpowder Tattoo in a 6-Year-Old Girl.

    PubMed

    Bernstein, Seth; Barros, Brittany; Zaenglein, Andrea L

    2016-05-01

    Gunpowder tattoos result from explosion and subsequent traumatic implantation of pigmented granules into varying layers of the skin. This report details the case of a 6-year-old with a gunpowder tattoo on the face. PMID:27040733

  17. Convergence Time towards Periodic Orbits in Discrete Dynamical Systems

    PubMed Central

    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

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

    PubMed

    San Martín, Jesús; Porter, Mason A

    2014-01-01

    We investigate the convergence towards periodic orbits in discrete dynamical systems. We examine the probability that a randomly chosen point converges to a particular neighborhood of a periodic orbit in a fixed number of iterations, and we use linearized equations to examine the evolution near that neighborhood. The underlying idea is that points of stable periodic orbit are associated with intervals. We state and prove a theorem that details what regions of phase space are mapped into these intervals (once they are known) and how many iterations are required to get there. We also construct algorithms that allow our theoretical results to be implemented successfully in practice. PMID:24736594

  19. 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.

  20. SMOS Instrument Performance and Calibration After 6 Years in Orbit

    NASA Astrophysics Data System (ADS)

    Oliva, R.

    2015-12-01

    ESA's Soil Moisture and Ocean Salinity (SMOS) mission has been in orbit for over 6 years, and its Microwave Imaging Radiometer with Aperture Synthesis (MIRAS) in two dimensions keeps working well. The data for this whole period has been recently reprocessed with the new fully polarimetric version (v620) of the Level-1 processor which also includes refined calibration schema for the antenna losses. This reprocessing has allowed the assessment of an improved performance benchmark. The long term drift exhibited by the previous processor version has been significantly mitigated thanks to a better calibration of the antenna losses and the use of only the most accurate Noise Injection Radiometer. These improvements have also reduced the orbital and seasonal variations, although residual drifts still remain, in particular during the satellite eclipse season. The spatial tilt existing in the images produced with the previous version of the Level-1 processor has been considerably decreased, removing the negative trend at low incidence angles and reducing the overall standard deviation of the spatial ripples. The expected improvement in the 3rd and 4th Stokes, after correcting the use of the cross-polar antenna patterns, has been confirmed, enabling accurate retrieval of the Faraday rotation angle. Finally, a better Sun and RFI flagging strategy has been implemented, allowing for the removal of the corrupted data. A problem which still persist in the new Level-1 data is the land-sea contamination. However, recent progress in the calibration investigations has shed new light on the origin of the land-sea contamination, linking it to visibility amplitude calibration errors. Thus, future versions of the Level-1 processor will have very much reduced land-sea contamination. An overview of the results and the progress achieved in both calibration and image reconstruction will be presented in this contribution.

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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.

  7. 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)

  8. Asymptotic stability on slow time scales from periodic systems

    SciTech Connect

    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.

  9. Childhood Sexual Abuse and Abuse-Specific Attributions of Blame over 6 Years Following Discovery

    ERIC Educational Resources Information Center

    Feiring, Candice; Cleland, Charles

    2007-01-01

    Objective: The purpose of this study was to examine patterns of change in attributions for childhood sexual abuse (CSA) over a 6-year period and whether such patterns were related to abuse severity, age, gender, and subsequent symptoms of depression and PTSD. Methodology: One-hundred and sixty children, 8-15 years old, were interviewed within 8…

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

    PubMed

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

    2016-04-01

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

  11. 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.

  12. Accurate frequency domain measurement of the best linear time-invariant approximation of linear time-periodic systems including the quantification of the time-periodic distortions

    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.

  13. Rossi X-Ray Timing Explorer All-Sky Monitor Detection of the Orbital Period of Scorpius X-1

    NASA Astrophysics Data System (ADS)

    Vanderlinde, Keith W.; Levine, Alan M.; Rappaport, Saul A.

    2003-06-01

    The orbital period of Scorpius X-1 has been accepted as 0.787313 days since its discovery in archival optical photometric data by Gottlieb, Wright, & Liller. This period has apparently been confirmed multiple times in the years since in both photometric and spectroscopic optical observations, although to date only marginal evidence has been reported for modulation of the X-ray intensity at that period. We have used data taken with the All Sky Monitor on board the Rossi X-Ray Timing Explorer over the past 6 years to search for such a modulation. A major difficulty in detecting the orbit in X-ray data is presented by the flaring behavior in this source, wherein the (1.5-12 keV) X-ray intensity can change by up to a factor of 2 within a fraction of a day. These flares contribute nearly white noise to Fourier transforms of the intensity time series and thereby tend to obscure weak modulations, i.e., of a few percent or less. We present herein a technique for substantially reducing the effects of the flaring behavior while, at the same time, retaining much of any periodic orbital modulation, provided only that the two temporal behaviors exhibit different spectral signatures. Through such a search, we have found evidence for orbital modulation at the ~1% level with a period of 0.78893 days. This period is equal within our accuracy to a period (0.78901 days) that differs by 1 cycle yr-1 from the accepted value and that was also detected by Gottlieb et al. at a strength nearly as great as that of the 0.787313 day periodicity. We note that many of the reported optical observations of Sco X-1 have been made within 1 or 2 months of early June, when Sco X-1 transits the meridian at midnight. All periodicity searches based only on such observations would have been subject to the same 1 cycle yr-1 alias that affected the search of Gottlieb and coworkers. These considerations lead us to suggest that the actual period may in fact be 0.78901 days and that further observations will

  14. 18.6-year Earth tide regulates geyser activity.

    PubMed

    Rinehart, J S

    1972-07-28

    Over 40 years of records from Yellowstone National Park, Wyoming, show that the 18.6-year tidal component strongly regulates the frequencies of eruption of Grand and Steamboat geysers. The frequency of Grand Geyser increases with increasing tidal force and that of Steamboat Geyser decreases, which suggests that tidal dilatation is one factor affecting heat flow to a geyser. PMID:17813197

  15. Changes in Sedentary Behaviours and Associations with Physical Activity through Retirement: A 6-Year Longitudinal Study

    PubMed Central

    Menai, Mehdi; Fezeu, Léopold; Charreire, Hélène; Kesse-Guyot, Emmanuelle; Touvier, Mathilde; Simon, Chantal; Weber, Christiane; Andreeva, Valentina A.; Hercberg, Serge; Oppert, Jean-Michel

    2014-01-01

    Changes in sedentary behaviours and physical activity according to retirement status need to be better defined. Retirement is a critical life period that may influence a number of health behaviours. We assessed past-year sedentary behaviours (television, computer and reading time during leisure, occupational and domestic sitting time, in h/week) and physical activity (leisure, occupational and domestic, in h/week) over 6 years (2000–2001 and 2007) using the Modifiable Activity Questionnaire in 2,841 participants (mean age: 57.3±5.0 y) of the SU.VI.MAX (Supplementation with Antioxidants and Minerals) cohort. Analyses were performed according to retirement status. Subjects retired in 2001 and 2007 (40%) were those who spent most time in sedentary behaviour and in physical activity during and outside leisure (p<0.001). Leisure-time sedentary behaviours increased in all subjects during follow-up (p<0.001), but subjects who retired between 2001 and 2007 (31%) were those who reported the greatest changes (+8.4±0.42 h/week for a combined indicator of leisure-time sedentary behaviour). They also had the greatest increase in time spent in leisure-time physical activity (+2.5±0.2 h/week). In subjects not retired 2001 and 2007 (29%), changes in time spent watching television were found positively associated with an increase in occupational physical activity (p = 0.04) and negatively associated with changes in leisure-time physical activity (p = 0.02). No consistent association between changes in sedentary behaviours and changes in physical activity was observed in subjects retired in 2001 and 2007. Public health interventions should target retiring age populations not only to encourage physical activity but also to limit sedentary behaviours. PMID:25259801

  16. 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...

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

    NASA Technical Reports Server (NTRS)

    Hailperin, Max

    1993-01-01

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

  18. 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. 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. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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.

  8. 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

  9. Taylor dispersion in the presence of time-periodic convection phenomena. Part I. Local-space periodicity

    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

  10. 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...

  11. 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...

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

    NASA Technical Reports Server (NTRS)

    Hailperin, M.

    1993-01-01

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

  13. Multiple Radiolucencies of the Jaws in a 6 Year Old.

    PubMed

    Hansford, John T; Kelsch, Robert D; Wiltz, Mauricio

    2015-11-01

    Radiolucencies of the jaws are a common finding. Mostly, they are isolated findings associated with inflammatory processes and consistent with inflammatory periapical disease, such as periapical cysts and periapical granulomas. If associated with the crowns of unerupted teeth, they may represent dentigerous cysts. However, occasionally, larger lytic/radiolucent lesions are identified; even more infrequently, these radiographic findings may be multiple and concurrent. The purpose of this report is to present the case of a 6-year-old female patient with no known concomitant syndrome who presented with multiple intraoral swellings and to discuss the treatment of multiple, bilateral mandibular and maxillary radiolucencies. PMID:26749783

  14. Root Resorption a 6-Year Follow-up Case Report

    PubMed Central

    Dias, Caroline; Closs, Luciane; Barletta, Fernando; Reston, Eduardo; Tovo, Maximiano F; Lambert, Paula

    2015-01-01

    This paper describes the clinical course of a pediatric patient developing cervical external root resorption (CERR). An 11-year old male patient had sustained dental trauma and was diagnosed with crown fracture affecting the incisal and middle thirds of the maxillary right permanent central incisor and the maxillary right permanent lateral incisor with pulp exposure and CERR after 24 months. Diagnosis and treatment of CERR are a challenge for dental practitioners. In this case, preservation of natural dentition is shown as a successful treatment in a 6-year follow-up. PMID:25870717

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. Brain Structural Integrity and Intrinsic Functional Connectivity Forecast 6 Year Longitudinal Growth in Children's Numerical Abilities

    PubMed Central

    Kochalka, John; Ngoon, Tricia J.; Wu, Sarah S.; Qin, Shaozheng; Battista, Christian

    2015-01-01

    Early numerical proficiency lays the foundation for acquiring quantitative skills essential in today's technological society. Identification of cognitive and brain markers associated with long-term growth of children's basic numerical computation abilities is therefore of utmost importance. Previous attempts to relate brain structure and function to numerical competency have focused on behavioral measures from a single time point. Thus, little is known about the brain predictors of individual differences in growth trajectories of numerical abilities. Using a longitudinal design, with multimodal imaging and machine-learning algorithms, we investigated whether brain structure and intrinsic connectivity in early childhood are predictive of 6 year outcomes in numerical abilities spanning childhood and adolescence. Gray matter volume at age 8 in distributed brain regions, including the ventrotemporal occipital cortex (VTOC), the posterior parietal cortex, and the prefrontal cortex, predicted longitudinal gains in numerical, but not reading, abilities. Remarkably, intrinsic connectivity analysis revealed that the strength of functional coupling among these regions also predicted gains in numerical abilities, providing novel evidence for a network of brain regions that works in concert to promote numerical skill acquisition. VTOC connectivity with posterior parietal, anterior temporal, and dorsolateral prefrontal cortices emerged as the most extensive network predicting individual gains in numerical abilities. Crucially, behavioral measures of mathematics, IQ, working memory, and reading did not predict children's gains in numerical abilities. Our study identifies, for the first time, functional circuits in the human brain that scaffold the development of numerical skills, and highlights potential biomarkers for identifying children at risk for learning difficulties. SIGNIFICANCE STATEMENT Children show substantial individual differences in math abilities and ease of math

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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.

  5. Cavitary lung lesion 6 years after renal transplantation.

    PubMed

    Subbiah, Arun Kumar; Arava, Sudheer; Bagchi, Soumita; Madan, Karan; Das, Chandan J; Agarwal, Sanjay Kumar

    2016-06-24

    The differential diagnoses of a cavitary lung lesion in renal transplant recipients would include infection, malignancy and less commonly inflammatory diseases. Bacterial infection, Tuberculosis, Nocardiosis, fungal infections like Aspergillosis and Cryptococcosis need to be considered in these patients. Pulmonary cryptococcosis usually presents 16-21 mo after transplantation, more frequently in patients who have a high level of cumulative immunosuppression. Here we discuss an interesting patient who never received any induction/anti-rejection therapy but developed both BK virus nephropathy as well as severe pulmonary Cryptococcal infection after remaining stable for 6 years after transplantation. This case highlights the risk of serious opportunistic infections even in apparently low immunologic risk transplant recipients many years after transplantation. PMID:27358792

  6. Cavitary lung lesion 6 years after renal transplantation

    PubMed Central

    Subbiah, Arun Kumar; Arava, Sudheer; Bagchi, Soumita; Madan, Karan; Das, Chandan J; Agarwal, Sanjay Kumar

    2016-01-01

    The differential diagnoses of a cavitary lung lesion in renal transplant recipients would include infection, malignancy and less commonly inflammatory diseases. Bacterial infection, Tuberculosis, Nocardiosis, fungal infections like Aspergillosis and Cryptococcosis need to be considered in these patients. Pulmonary cryptococcosis usually presents 16-21 mo after transplantation, more frequently in patients who have a high level of cumulative immunosuppression. Here we discuss an interesting patient who never received any induction/anti-rejection therapy but developed both BK virus nephropathy as well as severe pulmonary Cryptococcal infection after remaining stable for 6 years after transplantation. This case highlights the risk of serious opportunistic infections even in apparently low immunologic risk transplant recipients many years after transplantation. PMID:27358792

  7. 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.

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. Underground Corrosion of Activated Metals, 6-Year Exposure Analysis

    SciTech Connect

    M. K. Adler Flitton; T. S. Yoder

    2006-03-01

    The subsurface radioactive disposal site located at the Idaho National Laboratory contains neutronactivated metals from non-fuel nuclear-reactor-core components. A long-term underground corrosion test is being conducted to obtain site-specific corrosion rates to support efforts to more accurately estimate the transfer of activated elements in the surrounding arid vadose zone environment. The test uses nonradioactive metal coupons representing the prominent neutron-activated materials buried at the disposal location, namely, Type 304L stainless steel (UNS S30403), Type 316L stainless steel (S31603), nickel-chromium alloy (UNS NO7718), beryllium, aluminum 6061-T6 (A96061), and a zirconium alloy (UNS R60804). In addition, carbon steel (the material presently used in the cask disposal liners and other disposal containers) and a duplex stainless steel (UNS S32550) are also included in the test. This paper briefly describes the ongoing test and presents the results of corrosion analysis from coupons exposed underground for 1, 3, and 6 years.

  4. Cementless bulk alumina socket: preliminary results at 6 years.

    PubMed

    Hamadouche, M; Nizard, R S; Meunier, A; Bizot, P; Sedel, L

    1999-09-01

    To avoid polyethylene wear observed in total hip replacement, an alumina-alumina combination has been used since 1977. The aim of this study is to report the results of a hybrid alumina-alumina total hip arthroplasty with a cementless press-fit bulk alumina socket and a cemented titanium alloy stem in 55 patients (62 hips) operated on between 1982 and 1990. The bearing surfaces were a 32-mm alumina head articulating within the alumina socket. Four failures occurred: 3 aseptic loosenings of the socket and 1 femoral head fracture. Considering aseptic loosening as the endpoint, the survival rate was 93.2% after 6 years. At a mean of 72.1 months' follow-up, 92.4% of the surviving hips were graded as very good or good using the Merle d'Aubigné-Postel hip score. Radiolucent lines were observed on the acetabular side in 68.1 of the hips. The future of this interface, which is probably fibrous, remains questionable. With the exception of 1 femoral head fracture, all revisions were related to failure of the bony fixation of the socket, and no problem was encountered related to the alumina-alumina friction coupling. Alumina sockets with other types of cementless fixation have therefore been designed and are presently under clinical investigation. PMID:10512442

  5. Influence of allowable interruption period on estimates of accelerometer wear time and sedentary time in older adults

    PubMed Central

    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

  6. Recovery of the 6-year signal in length of day and its long-term decreasing trend

    NASA Astrophysics Data System (ADS)

    Duan, Pengshuo; Liu, Genyou; Liu, Lintao; Hu, Xiaogang; Hao, Xiaoguang; Huang, Yong; Zhang, Zhimin; Wang, Binbin

    2015-10-01

    There is a significant 6-year oscillation signal (called 6-year signal in this paper) existing in the interannual variations of length of day (LOD). It is unclear to understand its nature variation features. This paper extracts quantitatively the 6-year signal, from 1962~2012, using normal Morlet wavelet (NMWT) method combining wavelet packet and Fourier analysis technique, for the first time, and we investigate it in both time and frequency domains. The results indicate that the amplitude of a 6-year signal shows a long-term decreasing trend and the total amplitude reduction is about 0.05 ms during the past 50 years. The ratio of above reduction to the mean amplitude of 0.124 ms reaches 40 %. For interpreting the phenomenon on the above long-term decreasing trend, this paper proposes two alternatives; however, there is still no firm conclusion and it is required to be further explored.

  7. Fever of Unknown Origin in Children: A 6 year- Experience in a Tertiary Pediatric Egyptian Hospital

    PubMed Central

    Hassan, Rasha H; Fouda, Ashraf E; Kandil, Shaimaa M

    2014-01-01

    Background Fever of unknown origin (FUO) is among the most conditions which poses challenge in diagnosis. The presence of information on regional patterns of FUO will shorten the time for diagnosis and reduces health services costs. There are almost no previous studies describing the etiology of FUO in children of Egypt or nearby countries. Aim of the Study To determine different causes of FUO and the possible diagnostic procedures. Methods Data of patients with FUO, presented to the Infectious Diseases Unit of Mansoura University Children Hospital, were retrospectively collected in a 6 year-period from May 2006 to May 2011. The study included children with a fever of 38.3° C or more documented by a health care provider and for which the cause could not be identified after 3 weeks of evaluation as an outpatient or after a week of evaluation in hospital. Patients were then categorized into 5 groups. Results 127 patients met the diagnostic criteria. Infectious diseases were the commonest causes of FUO in 46 cases (36.22%) followed by the miscellaneous causes in 38 cases (29.9%). Meanwhile, collagen vascular diseases and malignancy were diagnosed in 13 cases (10.2%) and 10 cases (7.87%) respectively. While, 20 cases (15.75%) remained undiagnosed. Conclusions Infectious diseases are the commonest cause of FUO. The delay in diagnosis was due to atypical presentations or inappropriate use of antibiotic prior to the referral. Non infectious causes, malignancy and collagen or vascular disorders were diagnosed in rest of the patients. However, about 15% of our patients remained undiagnosed. The diagnosis was established by non-invasive means in more than two-third of the cases. PMID:24899875

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

    SciTech Connect

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

    2013-12-15

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

  9. Body Size and Intelligence in 6-year-olds

    PubMed Central

    Cornelius, Marie D.; Goldschmidt, Lidush; Willford, Jennifer A.; Leech, Sharon L.; Larkby, Cynthia; Day, Nancy L.

    2008-01-01

    Objectives Children born to teenage mothers are at risk for more physical and cognitive problems than those born to adult mothers. Our objective was to examine differences in size and intelligence between two cohorts of offspring born to adolescent (n = 357) and adult mothers (n = 668) who attended the same prenatal clinic. Methods Two prospective study cohorts were assessed children from gestation through age 6 years. The adult cohort was studied in the mid-1980’s and the teen cohort was evaluated in the mid-1990’s. Both samples were of low socio-economic status. The same study design and measures allowed us to adjust for the covariates of size and IQ. Results Offspring of adolescent mothers had a significantly smaller mean head circumference (5 mm) (HC) and higher body mass index (BMI) than offspring of adult mothers. Offspring of adolescent mothers scored significantly lower than the offspring of adult mothers on the Stanford-Binet (SBIS) composite score (4 points), and the quantitative (6.2 points), verbal reasoning (4.8 points), and short-term memory (3.9 points) area scores. Additional predictors of child IQ were maternal IQ, home environment, race, and number of siblings. When child HC was entered into our final regression model for the SBIS, maternal age and HC significantly predicted the composite score, the verbal reasoning, and short-term memory area scores. A 1 cm decrease in HC predicted a 1 point decrease in the SBIS composite score. Conclusions Compared to offspring of adult women, children of adolescent mothers have lower mean scores on cognitive measures, smaller head circumference, and higher BMI. These differences were significant after adjusting for differences between the two groups. Adolescent mothers and their children would benefit from interventions such as parenting support, education about nutritional needs, and advice on enriching the environments of their children. PMID:18683038

  10. 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...

  11. NHEXAS PHASE I REGION 5 STUDY--TIME-ACTIVITY DIARY QUESTIONNAIRE DATA (ALL MONITORING PERIODS)

    EPA Science Inventory

    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...

  12. Existence and exponential stability of positive almost periodic solution for Nicholson's blowflies models on time scales.

    PubMed

    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

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

    SciTech Connect

    Wilkening, Jon

    2008-07-01

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

  14. A statistical model for the timing of earthquakes and volcanic eruptions influenced by periodic processes

    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.

  15. Time periodic spatial disorder in a complex Ginzburg{endash}Landau equation

    SciTech Connect

    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.}

  16. Dynamics of phase slips in systems with time-periodic modulation.

    PubMed

    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

  17. Brief Family Intervention Effects on Adolescent Substance Initiation: School-Level Growth Curve Analyses 6 Years Following Baseline.

    ERIC Educational Resources Information Center

    Spoth, Richard; Redmond, Cleve; Shin, Chungyeol; Azevedo,Kari

    2004-01-01

    This study examines the effects of 2 brief family-focused interventions on the trajectories of substance initiation over a period of 6 years following a baseline assessment. The 2 interventions, designed for general-population families of adolescents, were the 7-session Iowa Strengthening Families Program (ISFP) (Molgaard & Spoth, 2001) and the…

  18. Fistula Formation 6 Years after Removal of Infected Pacemaker Leads

    PubMed Central

    Schroeter, Thomas; Kiefer, Philipp; Sauer, Matthias; Mohr, Friedrich Wilhelm

    2015-01-01

    We describe a case of a male patient who presented with a chronic ulcer below the left clavicle. Six years before the present admission a permanent pacemaker, including leads, was explanted related to endocarditis. The initial working hypothesis suspected an infected sebaceous gland as the cause of ulceration. After two periods of unsuccessful surgical treatment of the gland, further examination identified a small pacemaker lead fragment underneath the articulation between sternum and clavicle as a possible reason. PMID:26693129

  19. Fistula Formation 6 Years after Removal of Infected Pacemaker Leads.

    PubMed

    Schroeter, Thomas; Kiefer, Philipp; Sauer, Matthias; Mohr, Friedrich Wilhelm

    2015-12-01

    We describe a case of a male patient who presented with a chronic ulcer below the left clavicle. Six years before the present admission a permanent pacemaker, including leads, was explanted related to endocarditis. The initial working hypothesis suspected an infected sebaceous gland as the cause of ulceration. After two periods of unsuccessful surgical treatment of the gland, further examination identified a small pacemaker lead fragment underneath the articulation between sternum and clavicle as a possible reason. PMID:26693129

  20. Frequency domain system identification of helicopter rotor dynamics incorporating models with time periodic coefficients

    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

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

    PubMed

    Rasheed, Faraz; Alhajj, Reda

    2014-05-01

    Periodic pattern detection in time-ordered sequences is an important data mining task, which discovers in the time series all patterns that exhibit temporal regularities. Periodic pattern mining has a large number of applications in real life; it helps understanding the regular trend of the data along time, and enables the forecast and prediction of future events. An interesting related and vital problem that has not received enough attention is to discover outlier periodic patterns in a time series. Outlier patterns are defined as those which are different from the rest of the patterns; outliers are not noise. While noise does not belong to the data and it is mostly eliminated by preprocessing, outliers are actual instances in the data but have exceptional characteristics compared with the majority of the other instances. Outliers are unusual patterns that rarely occur, and, thus, have lesser support (frequency of appearance) in the data. Outlier patterns may hint toward discrepancy in the data such as fraudulent transactions, network intrusion, change in customer behavior, recession in the economy, epidemic and disease biomarkers, severe weather conditions like tornados, etc. We argue that detecting the periodicity of outlier patterns might be more important in many sequences than the periodicity of regular, more frequent patterns. In this paper, we present a robust and time efficient suffix tree-based algorithm capable of detecting the periodicity of outlier patterns in a time series by giving more significance to less frequent yet periodic patterns. Several experiments have been conducted using both real and synthetic data; all aspects of the proposed approach are compared with the existing algorithm InfoMiner; the reported results demonstrate the effectiveness and applicability of the proposed approach. PMID:23757597

  2. 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.

  3. 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.

  4. 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 =62.0(+/-7.7)Porb(days)+2.41(+/-1.87).

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

    PubMed

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

    2015-07-01

    Newly hatched chicks may be held longer than 48 h and experience long periods of fasting in commercial hatcheries. Limited information is known about the physiological status of chicks in such situations, due to the difficulty of precisely recording time of hatch. This study investigated the effect of the time from hatch to pulling (holding period) on physiological measures/parameters in 109 broiler chicks. Fertile Ross 308 eggs were incubated in a custom built small-scale incubator. The individual hatching time of each focal chick was determined using eggshell temperature monitoring. At 'pulling' (512 h of incubation time), the quality of focal chicks was assessed using the chick scoring method and physiological parameters were measured including BW, organ (heart, liver and stomach) weights, blood values and plasma corticosterone level. The time from hatch to pulling varied from 7.58 to 44.97 h. Egg weight at setting was significantly correlated with chick BW and weight of organs at pulling, but had no effect on chick quality, blood values and plasma corticosterone. Relative BW at pulling was negatively associated with the duration of holding period (P=0.002). However, there was a positive correlation between relative stomach weight and the duration of the holding period (P<0.001). As the holding period duration increased, there was a trend that blood partial pressure of oxygen, haematocrit and haemoglobin also increased, and blood partial pressure of carbon dioxide, total carbon dioxide and bicarbonate decreased (P<0.05). A wide range of plasma corticosterone was observed from chicks that had experienced different durations of holding period. We conclude that shortening the hatch window and minimising the number of chicks that experience a long holding period before pulling may improve chick quality and physiological status, which may be due to unfavourable environmental conditions that include feed and water deprivation. PMID:25711527

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

    NASA Astrophysics Data System (ADS)

    Ulker, Fatma Demet

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

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

    DOE PAGESBeta

    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

  8. 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.

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

    PubMed

    Chang, Shin-Shin; Chang, Jung-Hua

    2013-10-01

    Little research to date has been devoted to investigating whether people treat time differently from money when facing multiple gains or losses. This study tested the hypothesis that because time is characterized by perishability, fixed supply, and infungibility, people with strong motivation to obtain a long period of uninterrupted discretionary time would strive to trim the time needed for non-discretionary activities or to combine several non-discretionary activities. As a result, people prefer integration over segregation of multiple time losses or gains, which is not consistent with the prediction based on hedonic editing theory or the renewable resource model. This proposition is supported by results from four experiments. PMID:24597454

  10. Adaptive time-delayed stabilization of steady states and periodic orbits.

    PubMed

    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

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

    PubMed Central

    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

  12. 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.

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

    PubMed

    Xu, Shihe; Wei, Xiangqing; Zhang, Fangwei

    2016-01-01

    A time-delayed mathematical model for tumor growth with the effect of periodic therapy is studied. The establishment of the model is based on the reaction-diffusion dynamics and mass conservation law and is considered with a time delay in cell proliferation process. Sufficient conditions for the global stability of tumor free equilibrium are given. We also prove that if external concentration of nutrients is large the tumor will not disappear and the conditions under which there exist periodic solutions to the model are also determined. Results are illustrated by computer simulations. PMID:27274763

  14. Improvements in Lung Function and Height among Cohorts of 6-Year-Olds with Cystic Fibrosis from 1994 to 2012

    PubMed Central

    VanDevanter, Donald R.; Pasta, David J.; Konstan, Michael W.

    2014-01-01

    Objective To characterize spirometry and height changes in cohorts of 6-year-olds with cystic fibrosis (CF). Study design Global Lung Initiative (GLI) forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC) and FEV1/FVC and CDC height-for-age (HFA) Z-scores were generated for 6-year-olds in the from the CF Foundation Patient Registry (CFFPR) each year from 1994 and 2012. Z-score mean differences were analyzed by t-test and time trends of means by least squares regression for all children and for subgroups (sex, F580del mutation genotype, Medicaid insurance, and prenatal/newborn screening identification). Z-score distributions were compared by two-sample Kolmogorov-Smirnov tests. Results 11,670 children with CF were studied, of whom 50.5% were males, 50.2% had the F508del/F508del genotype, and 46.6% were insured by Medicaid. Mean HFA, FEV1 and FVC Z-scores increased significantly over the period in the entire population and all subgroups (P<0.001), but FEV1/FVC Z-scores were below normal and did not change significantly. In 2012, children identified by screening had significantly higher mean HFA (P=0.002), FEV1 (P<0.001) and FVC (P<0.001) Z-scores than those not screened, with 90% of FVC and 71.4% of FEV1 Z-scores greater than predicted by the Normal distribution; FEV1/FVC Z-scores were not different between screening groups. Conclusions Consistent, significant increases in HFA, FEV1, and FVC occurred from 1994–2012, but FEV1/FVC, a measure of airway obstruction, did not appreciably change. FVC and FEV1 Z-score distributions suggest that normative equation reference populations under-predict lung volumes of children with CF, but the reason(s) for this remain unclear. PMID:25134852

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

    PubMed

    Burggren, Warren W; Mueller, Casey A

    2015-01-01

    A critical window (sensitive period) represents a period during development when an organism's phenotype is responsive to intrinsic or extrinsic (environmental) factors. Such windows represent a form of developmental phenotypic plasticity and result from the interaction between genotype and environment. Critical windows have typically been defined as comprising discrete periods in development with a distinct starting time and end time, as identified by experiments following an on and an off protocol. Yet in reality, periods of responsiveness during development are likely more ambiguous that depicted. Our goal is to extend the concept of the developmental critical window by introducing a three-dimensional construct in which time during development, dose of the stressor applied, and the resultant phenotypic modification can be utilized to more realistically define a critical window. Using the example of survival of the brine shrimp (Artemia franciscana) during exposure to different salinity levels during development, we illustrate that it is not just stressor dose or exposure time but the interaction of these two factors that results in the measured phenotypic change, which itself may vary within a critical window. We additionally discuss a systems approach to critical windows, in which the components of a developing system--whether they be molecular, physiological, or morphological--may show differing responses with respect to time and dose. Thus, the plasticity of each component may contribute to a broader overall system response. PMID:25730265

  16. Modeling laser-induced periodic surface structures: Finite-difference time-domain feedback simulations

    SciTech Connect

    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.

  17. Natural convection in an enclosure under time periodic heating: An experimental study

    SciTech Connect

    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.

  18. Relaxation Time of Artificial Periodic Irregularities of the Ionospheric Plasma and Diffusion in the Inhomogeneous Atmosphere

    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.

  19. A Gaussian Process Based Online Change Detection Algorithm for Monitoring Periodic Time Series

    SciTech Connect

    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).

  20. Magic Memories: Young Children's Verbal Recall after a 6-Year Delay

    ERIC Educational Resources Information Center

    Jack, Fiona; Simcock, Gabrielle; Hayne, Harlene

    2012-01-01

    This report describes the first prospective study specifically designed to assess children's verbal memory for a unique event 6 years after it occurred. Forty-six 27- to 51-month-old children took part in a unique event and were interviewed about it twice, after 24-hr and 6-year delays. During the 6-year interview, 9 children verbally recalled the…

  1. 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…

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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…

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

    PubMed

    Amiraliyev, Gabil M; Ucar, Aysenur

    2013-01-01

    The periodical in time problem for singularly perturbed second order linear ordinary differential equation is considered. The boundary layer behavior of the solution and its first and second derivatives have been established. An example supporting the theoretical analysis is presented. PMID:24369452

  8. Forum Page Letters in the "Straits Times" of Singapore during Relatively Free and Restricted Press Periods.

    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…

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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)

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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…

  20. 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...

  1. 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.…

  2. 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?...

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

    PubMed

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

    2016-01-01

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

  4. 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

  5. Determination of Optimum Period between Inspections for Distribution System based on Availability Accounting Uncertainties in Inspection Time and Repair Time

    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.

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

    PubMed Central

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

    2011-01-01

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

  7. 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.

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

    NASA Technical Reports Server (NTRS)

    Lochner, James C.; Roussel-Dupre, Diane

    1994-01-01

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

  9. Alcohol Challenge Responses Predict Future Alcohol Use Disorder Symptoms: A 6-Year Prospective Study

    PubMed Central

    King, Andrea C.; McNamara, Patrick J.; Hasin, Deborah S.; Cao, Dingcai

    2014-01-01

    Background Propensity for alcohol misuse may be linked to an individuals’ response to alcohol. This study examined the role of alcohol response phenotypes to future drinking problems. Methods One hundred four young heavy social drinkers participated in a within-subject, double-blind, placebo-controlled laboratory alcohol challenge study with 6-year follow-up. Participants were examined for subjective responses before and after receiving an intoxicating dose of alcohol (.8 g/kg) or a placebo beverage, given in random order. Follow-up was conducted in 5 waves over 6 years after the sessions to assess drinking behaviors and alcohol use disorder (AUD) symptoms. Retention was high with 98% (509 of 520) of possible follow-ups completed. Results Greater sensitivity to alcohol, in terms of stimulation and rewarding effects (like, want more) and lower sensitivity to alcohol sedation predicted greater number of AUD symptoms through 6 years of follow-up. Cluster analyses revealed that for half the sample, increasing levels of stimulation and liking were predictors of more AUD symptoms with the other half divided between those showing like and want more and want more alone as significant predictors. Conclusions The findings extend previous findings and offer new empirical insights into the propensity for excessive drinking and alcohol problems. Heightened alcohol stimulation and reward sensitivity robustly predicted more alcohol use disorder symptoms over time associated with greater binge-drinking frequency. These drinking problems were maintained and progressed as these participants were entering their third decade of life, a developmental interval when continued alcohol misuse becomes more deviant. PMID:24094754

  10. 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.

  11. Estimating the incubation period of raccoon rabies: a time-space clustering approach.

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

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

  13. 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.

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

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

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

    PubMed Central

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

    2011-01-01

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

  16. 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.

  17. 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.

  18. Plasticity of the Intrinsic Period of the Human Circadian Timing System

    PubMed Central

    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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  20. 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.

  1. Primate enamel evinces long period biological timing and regulation of life history.

    PubMed

    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

  2. Time domain spectral method and its application on antenna array and PCB trace with periodic roughness

    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.

  3. Spin-dependent tunneling time in periodic diluted-magnetic-semiconductor/nonmagnetic-barrier superlattices

    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.

  4. Computation of symmetric, time-periodic solutions of the vortex sheet with surface tension

    PubMed Central

    Ambrose, David M.; Wilkening, Jon

    2010-01-01

    A numerical method is introduced for the computation of time-periodic vortex sheets with surface tension separating two immiscible, irrotational, two-dimensional ideal fluids of equal density. The approach is based on minimizing a nonlinear functional of the initial conditions and supposed period that is positive unless the solution is periodic, in which case it is zero. An adjoint-based optimal control technique is used to efficiently compute the gradient of this functional. Special care is required to handle singular integrals in the adjoint formulation. Starting with a solution of the linearized problem about the flat rest state, a family of smooth, symmetric breathers is found that, at quarter-period time intervals, alternately pass through a flat state of maximal kinetic energy, and a rest state in which all the energy is stored as potential energy in the interface. In some cases, the interface overturns before returning to the initial, flat configuration. It is found that the bifurcation diagram describing these solutions contains several disjoint curves separated by near-bifurcation events. PMID:20133691

  5. 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.

  6. Tracing temperature in a nanometer size region in a picosecond time period.

    PubMed

    Nakajima, Kaoru; Kitayama, Takumi; Hayashi, Hiroaki; Matsuda, Makoto; Sataka, Masao; Tsujimoto, Masahiko; Toulemonde, Marcel; Bouffard, Serge; Kimura, Kenji

    2015-01-01

    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

  7. Is the use of underwater polarized light by fish restricted to crepuscular time periods?

    PubMed

    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

  8. Tracing temperature in a nanometer size region in a picosecond time period

    NASA Astrophysics Data System (ADS)

    Nakajima, Kaoru; Kitayama, Takumi; Hayashi, Hiroaki; Matsuda, Makoto; Sataka, Masao; Tsujimoto, Masahiko; Toulemonde, Marcel; Bouffard, Serge; Kimura, Kenji

    2015-08-01

    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.

  9. Tracing temperature in a nanometer size region in a picosecond time period

    PubMed Central

    Nakajima, Kaoru; Kitayama, Takumi; Hayashi, Hiroaki; Matsuda, Makoto; Sataka, Masao; Tsujimoto, Masahiko; Toulemonde, Marcel; Bouffard, Serge; Kimura, Kenji

    2015-01-01

    Irradiation of materials with either swift heavy ions or slow highly charged ions leads to ultrafast heating on a timescale of several picosecond in a region of several nanometer. This ultrafast local heating result in formation of nanostructures, which provide a number of potential applications in nanotechnologies. These nanostructures are believed to be formed when the local temperature rises beyond the melting or boiling point of the material. Conventional techniques, however, are not applicable to measure temperature in such a localized region in a short time period. Here, we propose a novel method for tracing temperature in a nanometer region in a picosecond time period by utilizing desorption of gold nanoparticles around the ion impact position. The feasibility is examined by comparing with the temperature evolution predicted by a theoretical model. PMID:26293488

  10. Periodic solutions of a nonautonomous predator-prey system with stage structure and time delays

    NASA Astrophysics Data System (ADS)

    Xu, Rui; Wang, Zhiqiang

    2006-11-01

    A nonautonomous Lotka-Volterra type predator-prey model with stage structure and time delays is investigated. It is assumed in the model that the individuals in each species may belong to one of two classes: the immatures and the matures, the age to maturity is presented by a time delay, and that the immature predators do not feed on prey and do not have the ability to reproduce. By some comparison arguments we first discuss the permanence of the model. By using the continuation theorem of coincidence degree theory, sufficient conditions are derived for the existence of positive periodic solutions to the model. By means of a suitable Lyapunov functional, sufficient conditions are obtained for the uniqueness and global stability of the positive periodic solutions to the model.

  11. Time functions of deep earthquakes from broadband and short-period stacks

    USGS Publications Warehouse

    Houston, H.; Benz, H.M.; Vidale, J.E.

    1998-01-01

    To constrain dynamic source properties of deep earthquakes, we have systematically constructed broadband time functions of deep earthquakes by stacking and scaling teleseismic P waves from U.S. National Seismic Network, TERRAscope, and Berkeley Digital Seismic Network broadband stations. We examined 42 earthquakes with depths from 100 to 660 km that occurred between July 1, 1992 and July 31, 1995. To directly compare time functions, or to group them by size, depth, or region, it is essential to scale them to remove the effect of moment, which varies by more than 3 orders of magnitude for these events. For each event we also computed short-period stacks of P waves recorded by west coast regional arrays. The comparison of broadband with short-period stacks yields a considerable advantage, enabling more reliable measurement of event duration. A more accurate estimate of the duration better constrains the scaling procedure to remove the effect of moment, producing scaled time functions with both correct timing and amplitude. We find only subtle differences in the broadband time-function shape with moment, indicating successful scaling and minimal effects of attenuation at the periods considered here. The average shape of the envelopes of the short-period stacks is very similar to the average broadband time function. The main variations seen with depth are (1) a mild decrease in duration with increasing depth, (2) greater asymmetry in the time functions of intermediate events compared to deep ones, and (3) unexpected complexity and late moment release for events between 350 and 550 km, with seven of the eight events in that depth interval displaying markedly more complicated time functions with more moment release late in the rupture than most events above or below. The first two results are broadly consistent with our previous studies, while the third is reported here for the first time. The greater complexity between 350 and 550 km suggests greater heterogeneity in

  12. Sobolev type equations of time-fractional order with periodical boundary conditions

    NASA Astrophysics Data System (ADS)

    Plekhanova, Marina

    2016-08-01

    The existence of a unique local solution for a class of time-fractional Sobolev type partial differential equations endowed by the Cauchy initial conditions and periodical with respect to every spatial variable boundary conditions on a parallelepiped is proved. General results are applied to study of the unique solvability for the initial boundary value problem to Benjamin-Bona-Mahony-Burgers and Allair partial differential equations.

  13. Conditions for Recurrence of a Flow of Physical Events with Unextendable Dead Time Period

    NASA Astrophysics Data System (ADS)

    Nezhel'skaya, L. A.

    2016-04-01

    A flow of physical events (photons, electrons, etc.) is studied. One of the mathematical models of such flows is the modulated MAP flow of events circulating under conditions of unextendable dead time period. The explicit form of the probability density of interarrival interval of the flow is presented together with the explicit form of the joint probability density of two adjacent intervals in the observed flow. The conditions for recurrence of the observable flow of events are presented.

  14. The place of arthrography in the diagnosis and management of meniscal injuries--a 6-year review.

    PubMed Central

    Evans, S E; Chandy, J; Aldridge, M J

    1991-01-01

    Four hundred and eighty-seven consecutive knee arthrograms, performed over a 6-year period, are reviewed. Their accuracy is compared with arthroscopy and, where appropriate, with arthrotomy. The increasing accuracy of arthrography has resulted in the acceptance of this method of imaging as a useful and accurate means of examining meniscal injuries in the knee. This has led to far fewer surgical procedures and an overall saving of resources. PMID:2013891

  15. Thermal characteristics of time-periodic electroosmotic flow in a circular microchannel

    NASA Astrophysics Data System (ADS)

    Moghadam, Ali Jabari

    2015-10-01

    A theoretical analysis is performed to explore the thermal characteristics of electroosmotic flow in a circular microchannel under an alternating electric field. An analytical approach is presented to solve energy equation, and then, the exact solution of temperature profiles is obtained by using the Green's function method. This study reveals that the temperature field repeats itself for each half-period. Frequency has a strong influence on the thermal behavior of the flow field. For small values of the dimensionless frequency (small channel size, large kinematic viscosity, or small frequency), the advection mechanism is dominant in the whole domain and the resultant heating (Joule heating and wall heat flux) can be transferred by the complete flow field in the axial direction; while, the middle portion of the flow field at high dimensionless frequencies does not have sufficient time to transfer heat by advection, and the bulk fluid temperature, especially in heating, may consequently become greater than the wall temperature. In a particular instance of cooling mode, a constant surface temperature case is temporarily occurred in which the axial temperature gradient will be zero. For relatively high frequencies, the unsteady bulk fluid temperature in some radial positions at some moments may be equal to the wall temperature; hence instantaneous cylindrical surfaces with zero radial heat flux may occur over a period of time. Depending on the value and sign of the thermal scale ratio, the quasi-steady-state Nusselt number (time-averaged at one period) approaches a specific value as the electrokinetic radius becomes infinity.

  16. Enhancement in dentin collagen’s biological stability after proanthocyanidins treatment in clinically relevant time periods

    PubMed Central

    Liu, Yi; Chen, Mingsheng; Yao, Xiaomei; Xu, Changqi; Zhang, Ying; Wang, Yong

    2013-01-01

    Objective To investigate whether proanthocyanidins (PA) is capable of improving dentin collagen’s biological stability through cross-linking within time periods that are clinically relevant. Materials and methods Demineralized dentin collagen slabs were treated with 3.75 wt% PA solution for 10 s, 1 min, 30 min, 60 min, 120 min, 360 min, and 720 min, respectively. The resultant cross-linked collagen samples were subject to digestion with 0.1% collagenase at 37 °C for 2 h, 6 h, 12 h, 24 h, 36 h, and 48 h. The percentage of weight loss after digestion was calculated to evaluate PA-treated collagen’s resistance toward enzymatic degradation. Fourier-Transformed Infrared (FTIR) spectroscopy was used to probe evidences of PA-collagen interactions after various periods of PA treatment. Results The collagenase digestion assay suggests that PA treatment as short as 10 s can enhance collagen’s resistance toward enzymatic challenge. The FTIR spectroscopy further verifies that PA is indeed incorporated into collagen regardless of treatment time, possibly via a mechanism involving the chemical interactions between PA and collagen. Significance This study confirmed that PA can effectively cross-link collagen and improve its biological stability in time periods as short as 10 s. The use of PA as a priming agent is therefore clinically feasible and is a promising approach to improving the durability of current dentin bonding systems. PMID:23434233

  17. Time-frequency manifold correlation matching for periodic fault identification in rotating machines

    NASA Astrophysics Data System (ADS)

    He, Qingbo; Wang, Xiangxiang

    2013-05-01

    For rotating machines, the localized faults of key components generally represent as periodic transient impulses in vibration signals. The existence of background noise will corrupt transient impulses in practice, and will thus increase the difficulty to identify specific faults. This paper combines the concepts of time-frequency manifold (TFM) and image template matching, and proposes a novel TFM correlation matching method to enhance identification of the periodic faults. This method is to conduct correlation matching of a vibration signal in the time-frequency domain by using the TFM with a short duration as a template. By this method, the time-frequency distribution (TFD) of a vibration signal is firstly achieved by the Smoothed Pseudo-Wigner-Ville distribution (SPWVD) method. Then the TFM template is learned to do correlation matching with the TFD of the analyzed signal. Finally, the ridge is extracted from the correlation matching image and the ridge coefficients are analyzed for periodic fault identification. The proposed method takes advantages of the TFM in noise suppression and template matching in object enhancement, and can enhance the fault impulses of interest in a unified scale. The novel method is verified to be superior to traditional enveloping method with providing smoother and clearer fault impulse component via applications to gearbox fault detection and bearing defect identification.

  18. An approach to identify time consistent model parameters: sub-period calibration

    NASA Astrophysics Data System (ADS)

    Gharari, S.; Hrachowitz, M.; Fenicia, F.; Savenije, H. H. G.

    2013-01-01

    Conceptual hydrological models rely on calibration for the identification of their parameters. As these models are typically designed to reflect real catchment processes, a key objective of an appropriate calibration strategy is the determination of parameter sets that reflect a "realistic" model behavior. Previous studies have shown that parameter estimates for different calibration periods can be significantly different. This questions model transposability in time, which is one of the key conditions for the set-up of a "realistic" model. This paper presents a new approach that selects parameter sets that provide a consistent model performance in time. The approach consists of testing model performance in different periods, and selecting parameter sets that are as close as possible to the optimum of each individual sub-period. While aiding model calibration, the approach is also useful as a diagnostic tool, illustrating tradeoffs in the identification of time-consistent parameter sets. The approach is applied to a case study in Luxembourg using the HyMod hydrological model as an example.

  19. Periodic Time-Domain Nonlocal Nonreflecting Boundary Conditions for Duct Acoustics

    NASA Technical Reports Server (NTRS)

    Watson, Willie R.; Zorumski, William E.

    1996-01-01

    Periodic time-domain boundary conditions are formulated for direct numerical simulation of acoustic waves in ducts without flow. Well-developed frequency-domain boundary conditions are transformed into the time domain. The formulation is presented here in one space dimension and time; however, this formulation has an advantage in that its extension to variable-area, higher dimensional, and acoustically treated ducts is rigorous and straightforward. The boundary condition simulates a nonreflecting wave field in an infinite uniform duct and is implemented by impulse-response operators that are applied at the boundary of the computational domain. These operators are generated by convolution integrals of the corresponding frequency-domain operators. The acoustic solution is obtained by advancing the Euler equations to a periodic state with the MacCormack scheme. The MacCormack scheme utilizes the boundary condition to limit the computational space and preserve the radiation boundary condition. The success of the boundary condition is attributed to the fact that it is nonreflecting to periodic acoustic waves. In addition, transient waves can pass rapidly out of the solution domain. The boundary condition is tested for a pure tone and a multitone source in a linear setting. The effects of various initial conditions are assessed. Computational solutions with the boundary condition are consistent with the known solutions for nonreflecting wave fields in an infinite uniform duct.

  20. Time-varying singular value decomposition for periodic transient identification in bearing fault diagnosis

    NASA Astrophysics Data System (ADS)

    Zhang, Shangbin; Lu, Siliang; He, Qingbo; Kong, Fanrang

    2016-09-01

    For rotating machines, the defective faults of bearings generally are represented as periodic transient impulses in acquired signals. The extraction of transient features from signals has been a key issue for fault diagnosis. However, the background noise reduces identification performance of periodic faults in practice. This paper proposes a time-varying singular value decomposition (TSVD) method to enhance the identification of periodic faults. The proposed method is inspired by the sliding window method. By applying singular value decomposition (SVD) to the signal under a sliding window, we can obtain a time-varying singular value matrix (TSVM). Each column in the TSVM is occupied by the singular values of the corresponding sliding window, and each row represents the intrinsic structure of the raw signal, namely time-singular-value-sequence (TSVS). Theoretical and experimental analyses show that the frequency of TSVS is exactly twice that of the corresponding intrinsic structure. Moreover, the signal-to-noise ratio (SNR) of TSVS is improved significantly in comparison with the raw signal. The proposed method takes advantages of the TSVS in noise suppression and feature extraction to enhance fault frequency for diagnosis. The effectiveness of the TSVD is verified by means of simulation studies and applications to diagnosis of bearing faults. Results indicate that the proposed method is superior to traditional methods for bearing fault diagnosis.

  1. The Preschool Attention-Deficit/Hyperactivity Disorder Treatment Study (PATS) 6-Year Follow-up

    PubMed Central

    Riddle, Mark A.; Yershova, Kseniya; Lazzaretto, Deborah; Paykina, Natalya; Yenokyan, Gayane; Greenhill, Laurence; Abikoff, Howard; Vitiello, Benedetto; Wigal, Tim; McCracken, James T.; Kollins, Scott H.; Murray, Desiree W.; Wigal, Sharon; Kastelic, Elizabeth; McGough, James J.; dosReis, Susan; Bauzó-Rosario, Audrey; Stehli, Annamarie; Posner, Kelly

    2013-01-01

    Objective To describe the clinical course of attention-deficit/hyperactivity disorder (ADHD) symptom severity and diagnosis from ages 3–5 to 9–12 years during a 6-year follow-up after the original Preschool ADHD Treatment Study (PATS). Method 207 participants (75% male) from the original PATS, assessed at Baseline (mean age 4.4 years, when all met criteria for ADHD) and 3-months later (prior to medication treatment), were re-evaluated in three follow-up assessment visits (Year 3, mean age 7.4 years; Year 4, 8.3 years and Year 6, 10.4 years). Parents and teachers rated symptom severity and clinicians established psychiatric diagnoses. Analyses examined longitudinal changes in symptom severity and ADHD diagnosis. Results Parent- and teacher-rated symptom severity decreased from Baseline to Year 3 but remained relatively stable and in the moderate-to-severe clinical range through Year 6. Girls showed generally steeper decreases in symptom T-scores. At Year 6, 89% (160/180) of remaining participants met ADHD symptom and impairment diagnostic criteria. Comorbidity of oppositional defiant disorder and/or conduct disorder was associated with a 30% higher risk of having an ADHD diagnosis at Year 6 in the multiple logistic model. Medication status during follow-up, on vs. off, did not predict symptom severity change from Year 3 to Year 6 after adjustment for other variables. Conclusions ADHD in preschoolers is a relatively stable diagnosis over a 6-year period. The course is generally chronic, with high symptom severity and impairment, in very young children with moderate-to-severe ADHD, despite treatment with medication. Development of more effective ADHD intervention strategies is needed for this age group. PMID:23452683

  2. Spacecraft stability and control using new techniques for periodic and time-delayed systems

    NASA Astrophysics Data System (ADS)

    NAzari, Morad

    This dissertation addresses various problems in spacecraft stability and control using specialized theoretical and numerical techniques for time-periodic and time-delayed systems. First, the effects of energy dissipation are considered in the dual-spin spacecraft, where the damper masses in the platform (?) and the rotor (?) cause energy loss in the system. Floquet theory is employed to obtain stability charts for different relative spin rates of the subsystem [special characters omitted] with respect to the subsystem [special characters omitted]. Further, the stability and bifurcation of delayed feedback spin stabilization of a rigid spacecraft is investigated. The spin is stabilized about the principal axis of the intermediate moment of inertia using a simple delayed feedback control law. In particular, linear stability is analyzed via the exponential-polynomial characteristic equations and then the method of multiple scales is used to obtain the normal form of the Hopf bifurcation. Next, the dynamics of a rigid spacecraft with nonlinear delayed multi-actuator feedback control are studied, where a nonlinear feedback controller using an inverse dynamics approach is sought for the controlled system to have the desired linear delayed closed-loop dynamics (CLD). Later, three linear state feedback control strategies based on Chebyshev spectral collocation and the Lyapunov Floquet transformation (LFT) are explored for regulation control of linear periodic time delayed systems. First , a delayed feedback control law with discrete delay is implemented and the stability of the closed-loop response is investigated in the parameter space of available control gains using infinite-dimensional Floquet theory. Second, the delay differential equation (DDE) is discretized into a large set of ordinary differential equations (ODEs) using the Chebyshev spectral continuous time approximation (CSCTA) and delayed feedback with distributed delay is applied. The third strategy involves

  3. Quasiequilibrium directed hopping in a time-dependent two-well periodic potential

    NASA Astrophysics Data System (ADS)

    Rozenbaum, V. M.; Shapochkina, I. V.

    2011-11-01

    We consider the directed motion of a Brownian particle in a two-well periodic potential with time-varying barriers and wells described by arbitrary periodic functions of time, v(t) and u(t), alternating with the period τ. In the framework of the low-temperature kinetic approach, we obtain explicit formulas for the probabilities of finding the particle in potential wells, average velocity of directed motion, input energy Pin and useful work Pout against additionally introduced stationary load force f. These formulas are considerably simplified by the assumption of the quasiequilibrium regime of motion corresponding to small values of u(t) and f. It is shown that depending on the same or opposite parity of the functions v(t) and u(t) with respect to time reversal, the motion direction of a Brownian particle is retained or reversed under the reversal of the direction of movement along the (v-u) loop in the phase space of the functions v(t) and u(t), and the nondiagonal kinetic coefficients are mutually symmetric or antisymmetric. In the adiabatic limit τ→∞, the average velocity is proportional to τ-1 in two cases: (i) the above loop has a nonzero area, (ii) the functions v(t) and u(t) are proportional to each other (zero loop area) and include intervals of fast changes with small durations τ0 on the period τ of their variations. In both of these cases, the efficiency of energy conversion, η=Pout/Pin, tends to unity at large variations of the barriers v(t). In the second case, the deviation of η from unity can be split into two contributions: The former decreases exponentially with increasing amplitude v0 of v(t), while the latter is a small nonadiabatic correction proportional to v0-3/2. It is the nonadiabatic correction that limits high efficiencies at large variations of barriers.

  4. Infrared Time Lags for the Periodic Quasar PG 1302-102

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    The optical light curve of the quasar PG 1302-102 at z=0.278 shows a strong, smooth 5.2 year periodic signal, detectable over a period of ∼20 years. Although the interpretation of this phenomenon is still uncertain, the most plausible mechanisms involve a binary system of two supermassive black holes with a subparsec separation. At this close separation, the nuclear black holes in PG 1302-102 will likely merge within ∼ {10}5 years due to gravitational wave emission alone. Here, we report the rest-frame near-infrared time lags for PG 1302-102. Compiling data from WISE and Akari, we confirm that the periodic behavior reported in the optical light curve from Graham et al. is reproduced at infrared wavelengths, with best-fit observed-frame 3.4 and 4.6 μ {{m}} time lags of (2219 ± 153, 2408 ± 148) days for a near face-on orientation of the torus, or (4103 ± 153, 4292 ± 148) days for an inclined system with relativistic Doppler boosting in effect. The periodicity in the infrared light curves and the light-travel time of the accretion disk photons to reach the dust glowing regions support that a source within the accretion disk is responsible for the optical variability of PG 1302-102, echoed at the farther out dusty regions. The implied distance of this dusty, assumed toroidal region is ∼1.5 pc for a near face-on geometry or ∼1.1 pc for the relativistic Doppler-boosted case.

  5. Timing Studies of X Persei and the Discovery of Its Transient Quasi-periodic Oscillation Feature

    NASA Technical Reports Server (NTRS)

    Acuner, Z.; Inam,S. C.; Sahiner, S.; Serim, M. M.; Baykal, A.; Swank, J.

    2014-01-01

    We present a timing analysis of X Persei (X Per) using observations made between 1998 and 2010 with the Proportional Counter Array (PCA) onboard the Rossi X-ray Timing Explorer (RXTE) and with the INTEGRAL Soft Gamma-Ray Imager (ISGRI). All pulse arrival times obtained from the RXTE-PCA observations are phase-connected and a timing solution is obtained using these arrival times. We update the long-term pulse frequency history of the source by measuring its pulse frequencies using RXTE-PCA and ISGRI data. From the RXTEPCA data, the relation between the frequency derivative and X-ray flux suggests accretion via the companion's stellar wind. However, the detection of a transient quasi-periodic oscillation feature, peaking at approximately 0.2 Hz, suggests the existence of an accretion disc. We find that doublebreak models fit the average power spectra well, which suggests that the source has at least two different accretion flow components dominating the overall flow. From the power spectrum of frequency derivatives, we measure a power-law index of approximately - 1, which implies that, on short time-scales, disc accretion dominates over noise, while on time-scales longer than the viscous time-scales, the noise dominates. From pulse profiles, we find a correlation between the pulse fraction and the count rate of the source.

  6. Escape rate for a quantum particle moving in a time-periodic rapidly oscillating potential: a time-independent approach.

    PubMed

    Shit, Anindita; Chattopadhyay, Sudip; Chaudhuri, Jyotipratim Ray

    2012-05-01

    We explore, in the quantum regime, the stochastic dynamics of a time-periodic, rapidly oscillating potential (having a characteristic frequency of ω) within the framework of a time-dependent system-reservoir Hamiltonian. We invoke the idea of a quantum gauge transformation in light of the standard Floquet theorem in an attempt to construct a Langevin equation (bearing a time-independent effective potential) by employing a systematic perturbative expansion in powers of ω^{-1} using the natural time-scale separation. The time-independent effective potential (corrected to ω^{-2} in leading order) that acts on the slow motion of the driven particle can be employed for trapping. We proceed further to evaluate the rate of escape of the driven particle from the metastable state in the high-temperature limit. We also envisage a resonance phenomena, a true hallmark of the system-reservoir quantization. This development would thus serve as a model template to investigate the trapping mechanism, as well as an appropriate analog to understand the dynamics of a fluctuation-induced escape process from the trap. PMID:23004698

  7. Transfer-matrix approach for finite-difference time-domain simulation of periodic structures.

    PubMed

    Deinega, Alexei; Belousov, Sergei; Valuev, Ilya

    2013-11-01

    Optical properties of periodic structures can be calculated using the transfer-matrix approach, which establishes a relation between amplitudes of the wave incident on a structure with transmitted or reflected waves. The transfer matrix can be used to obtain transmittance and reflectance spectra of finite periodic structures as well as eigenmodes of infinite structures. Traditionally, calculation of the transfer matrix is performed in the frequency domain and involves linear algebra. In this work, we present a technique for calculation of the transfer matrix using the finite-difference time-domain (FDTD) method and show the way of its implementation in FDTD code. To illustrate the performance of our technique we calculate the transmittance spectra for opal photonic crystal slabs consisting of multiple layers of spherical scatterers. Our technique can be used for photonic band structure calculations. It can also be combined with existing FDTD methods for the analysis of periodic structures at an oblique incidence, as well as for modeling point sources in a periodic environment. PMID:24329377

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

    PubMed Central

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

    2016-01-01

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

  9. Concentration of hydrogen ions in several calcium hydroxide pastes over different periods of time.

    PubMed

    Vianna, Morgana Eli; Zilio, Danila M; Ferraz, Caio Cezar Randi; Zaia, Alexandre Augusto; de Souza-Filho, Francisco José; Gomes, Brenda Paula Figueiredo de Almeida

    2009-01-01

    The purpose of this in vitro study was to measure the concentration of hydrogen ions (pH) of calcium hydroxide [(Ca(OH)2] pastes combined with different vehicles over 7 periods of time. The Ca(OH)2 was manipulated with the following vehicles: i: sterile water; ii: iodoform plus sterile water; iii: local anesthetics (Lydocaine 2% with 1: 100,000 epinephrine); iv: polyethyleneglycol; v: glycerin; vi: 2.0% chlorhexidine gel; vii: camphorated paramonochlorophenol (CMCP); viii: (CMCP) + glycerin; and ix: polyethyleneglycol plus CMCP. The pastes were made on a glass plate to toothpaste consistency and the pH was measured at the following times: 5 min, 1, 24, 48 h; 7, 14 and 28 days. The data were statistically analyzed (Kruskal-Wallis at p<0.05). At 5 min, 1 and 24 h, the pH of all tested pastes ranged from 13.05 to 11.16. At 48 h and 7 days the pH of all tested pastes ranged from 11.66 to 8.92. At 14 and 28 days almost all pastes had pH means lower than 10. In conclusion, the mean pH of all tested calcium hydroxide pastes decreased with the time. Pastes made with aqueous vehicles (especially with sterile water), followed by oily vehicles (especially with CMCP + glycerin), held the highest pH means over the periods of time tested. PMID:20126906

  10. Performance of ROB's near real-time ionospheric product during normal and disturbed space weather periods.

    NASA Astrophysics Data System (ADS)

    Bergeot, Nicolas; Chevalier, Jean-Marie; Bruyninx, Carine

    2015-04-01

    Several agencies are routinely monitoring the vertical Total Electron Content (vTEC) using GNSS data. Derived maps are available with different latencies, area extents, and grid/time resolutions. However, no high-resolution maps are publically available over Europe in near real-time. In this frame, the Royal Observatory of Belgium (ROB) developed the ROB-IONO software which takes advantage of the dense EUREF Permanent GNSS Network (EPN) to monitor the ionosphere. The main ROB products consist of ionospheric vTEC maps over Europe and their variability estimated in near real-time every 15 min on 0.5° x 0.5° grids using GPS observations. The maps are available online with a latency of ~3 min in the IONEX format at ftp://gnss.oma.be and as interactive web pages at www.gnss.be. During normal ionospheric activity, the ROB-TEC maps show a good agreement with widely used post-processed global products from IGS, CODE and ESA, with mean differences of 1.3 ± 0.9, 0.6 ± 0.7 and 0.4 ± 1.6 TECu respectively for the period 2012 to mid-2013. For a disturbed period, such as the 2003 Halloween ionospheric storm, the mean differences with IGS, CODE and ESA maps are respectively 0.9 ± 2.2, 0.1 ± 2.0 and 0.6 ± 6.8 TECu, with maximum differences (>38 TECu) occurring during the major phase of the storm. These differences are due to the lower resolution of global products in time and space compared to the ROB-TEC maps. A description of two recent events, on March 17, 2013 and February 27, 2014 highlights the capability of the method adopted to detect in near real-time abnormal ionospheric behaviour over Europe. The potential of the variability maps as an indicator of rapid ionospheric variations during the 15 min of observations is also highlighted. More than 30 ionospheric events associated with Space weather were detected during the period 2012-2014. The ionospheric perturbations are associated with Coronal Mass Ejections (CMEs, ~70% of the time), active geomagnetic conditions

  11. Dynamic effective properties of heterogeneous geological formations with spherical inclusions under periodic time variations

    NASA Astrophysics Data System (ADS)

    Rabinovich, A.; Dagan, G.; Miloh, T.

    2013-04-01

    In unsteady groundwater flow (or similar processes of heat/electrical conduction), the heterogeneous medium structure is characterized by two random properties, the conductivity K and the specific storativity S. The average head field ⟨H ⟩and the associated effective properties Kef, Sef are determined for a layer with a periodic head drop between boundaries, such that H is periodic in time, and a medium made up of a matrix with a dilute concentration of spherical inclusions. In the common quasi-steady approximation, Kef is equal to the classical steady solution while Sef = SA, the arithmetic mean. We derive expressions for the frequency dependent Kef, Sef, which are generally complex, i.e., dynamic. The main result is the delineation of the ranges of the parameters: dimensionless frequency (ω) and contrasts of conductivity (κ) and storativity (s) between the matrix and the inclusions, for which dynamic effects are significant.

  12. Ultrafast time dynamics studies of periodic lattices with free electron laser radiation

    SciTech Connect

    Quevedo, W.; Busse, G.; Hallmann, J.; More, R.; Petri, M.; Rajkovic, I.; Krasniqi, F.; Rudenko, A.; Tschentscher, T.; Stojanovic, N.; Duesterer, S.; Treusch, R.; Tolkiehn, M.; Techert, S.

    2012-11-01

    It has been proposed that radiation from free electron laser (FEL) at Hamburg (FLASH) can be used for ultrafast time-resolved x-ray diffraction experiments based on the near-infrared (NIR) pump/FEL probe scheme. Here, investigation probing the ultrafast structural dynamics of periodic nano-crystalline organic matter (silver behenate) with such a scheme is reported. Excitation with a femtosecond NIR laser leads to an ultrafast lattice modification which time evolution has been studied through the scattering of vacuum ultraviolet FEL pulses. The found effect last for 6 ps and underpins the possibility for studying nanoperiodic dynamics down to the FEL source time resolution. Furthermore, the possibility of extending the use of silver behenate (AgBh) as a wavelength and temporal calibration tool for experiments with soft x-ray/FEL sources is suggested.

  13. Evaluation of indoor air composition time variation in air-tight occupied spaces during night periods

    NASA Astrophysics Data System (ADS)

    Markov, Detelin

    2012-11-01

    This paper presents an easy-to-understand procedure for prediction of indoor air composition time variation in air-tight occupied spaces during the night periods. The mathematical model is based on the assumptions for homogeneity and perfect mixing of the indoor air, the ideal gas model for non-reacting gas mixtures, mass conservation equations for the entire system and for each species, a model for prediction of basal metabolic rate of humans as well as a model for prediction of O2 consumption rate and both CO2 and H2O generation rates by breathing. Time variation of indoor air composition is predicted at constant indoor air temperature for three scenarios based on the analytical solution of the mathematical model. The results achieved reveal both the most probable scenario for indoor air time variation in air-tight occupied spaces as well as the cause for morning tiredness after having a sleep in a modern energy efficient space.

  14. Time-headway distribution for periodic totally asymmetric exclusion process with various updates

    NASA Astrophysics Data System (ADS)

    Hrabák, P.; Krbálek, M.

    2016-03-01

    The totally asymmetric exclusion process (TASEP) with periodic boundaries is considered as traffic flow model. The large-L approximation of the stationary state is used for the derivation of the time-headway distribution (an important microscopic characteristic of traffic flow) for the model with generalized update (genTASEP) in both, forward- and backward-sequential representations. The usually used updates, fully-parallel and regular forward- and backward-sequential, are analyzed as special cases of the genTASEP. It is shown that only for those cases, the time-headway distribution is determined by the flow regardless to the density. The qualitative comparison of the results with traffic data demonstrates that the genTASEP with backward order and attractive interaction evinces similar properties of time-headway distribution as the real traffic sample.

  15. Timing and periodicity of paraglacial rock-slope failures in the Scottish Highlands

    NASA Astrophysics Data System (ADS)

    Ballantyne, Colin K.; Stone, John O.

    2013-03-01

    Many formerly-glaciated mountains exhibit a high density of postglacial rock-slope failures (RSFs) in the form of rockslides, rock avalanches or deep-seated gravitational slope deformations. Such RSFs are often termed 'paraglacial' as they reflect pre-conditioning by glaciation and deglaciation. The temporal pattern of paraglacial RSFs is unknown. We employ 47 cosmogenic isotope exposure ages obtained for 17 catastrophic RSFs in the Scottish Highlands to test models of changes in RSF frequency since deglaciation. Our results show that RSF activity spans almost the entire postglacial period from ~ 17 ka until ~ 1.5 ka, and that the periodicity of sampled postglacial RSFs is statistically indistinguishable from a pattern of uniform periodicity (~ 1 ka- 1). Our data do not conform to proposed models of declining RSF frequency with time elapsed since deglaciation, but suggest that the temporal distribution of postglacial RSFs is best described by a combination of rapid response (enhanced RSF frequency during or immediately after deglaciation) followed by approximately constant periodicity. Our findings are consistent with near-surface fracturing of rock when glacially-induced confining stresses are removed, causing some failures during or immediately after deglaciation and reducing other slopes to critical conditional stability so that failure is triggered by progressive rock-mass weakening or by transient triggering mechanisms. Neither permafrost degradation (thaw of ice in joints) nor seismic activity offers a general explanation for triggering Scottish RSFs, but could be contributory in some cases. The quasi-constant periodicity inferred for Holocene RSFs implies that the probability of RSFs in this seismically-quiescent intraplate area has not changed in the past ~ 10 ka, and that further (though infrequent) catastrophic RSFs are likely to occur in the future.

  16. Time-Periodic Solutions of Driven-Damped Trimer Granular Crystals

    DOE PAGESBeta

    Charalampidis, E. G.; Li, F.; Chong, C.; Yang, J.; Kevrekidis, P. G.

    2015-01-01

    We consider time-periodic structures of granular crystals consisting of alternate chrome steel (S) and tungsten carbide (W) spherical particles where each unit cell follows the pattern of a 2 : 1 trimer: S-W-S. The configuration at the left boundary is driven by a harmonic in-time actuation with given amplitude and frequency while the right one is a fixed wall. Similar to the case of a dimer chain, the combination of dissipation, driving of the boundary, and intrinsic nonlinearity leads to complex dynamics. For fixed driving frequencies in each of the spectral gaps, we find that the nonlinear surface modes and the statesmore » dictated by the linear drive collide in a saddle-node bifurcation as the driving amplitude is increased, beyond which the dynamics of the system becomes chaotic. While the bifurcation structure is similar for solutions within the first and second gap, those in the first gap appear to be less robust. We also conduct a continuation in driving frequency, where it is apparent that the nonlinearity of the system results in a complex bifurcation diagram, involving an intricate set of loops of branches, especially within the spectral gap. The theoretical findings are qualitatively corroborated by the experimental full-field visualization of the time-periodic structures.« less

  17. Hydromagnetic natural convection flow between vertical parallel plates with time-periodic boundary conditions

    NASA Astrophysics Data System (ADS)

    Adesanya, S. O.; Oluwadare, E. O.; Falade, J. A.; Makinde, O. D.

    2015-12-01

    In this paper, the free convective flow of magnetohydrodynamic fluid through a channel with time periodic boundary condition is investigated by taking the effects of Joule dissipation into consideration. Based on simplifying assumptions, the coupled governing equations are reduced to a set of nonlinear boundary valued problem. Approximate solutions are obtained by using semi-analytical Adomian decomposition method. The effect of pertinent parameters on the fluid velocity, temperature distribution, Nusselt number and skin friction are presented graphically and discussed. The result of the computation shows that an increase in the magnetic field intensity has significant influence on the fluid flow.

  18. The Cluster Science Archive: from Time Period to Physics Based Search

    NASA Astrophysics Data System (ADS)

    Masson, A.; Escoubet, C. P.; Laakso, H. E.; Perry, C. H.

    2015-12-01

    Since 2000, the Cluster spacecraft relay the most detailed information on how the solar wind affects our geospace in three dimensions. Science output from Cluster is a leap forward in our knowledge of space plasma physics: the science behind space weather. It has been key in improving the modeling of the magnetosphere and understanding its various physical processes. Cluster data have enabled the publication of more than 2000 refereed papers and counting. This substantial scientific return is often attributed to the online availability of the Cluster data archive, now called the Cluster Science Archive (CSA). It is being developed by the ESAC Science Data Center (ESDC) team and maintained alongside other science ESA archives at ESAC (ESA Space Astronomy Center, Madrid, Spain). CSA is a public archive, which contains the entire set of Cluster high-resolution data, and other related products in a standard format and with a complete set of metadata. Since May 2015, it also contains data from the CNSA/ESA Double Star mission (2003-2008), a mission operated in conjunction with Cluster. The total amount of data format now exceeds 100 TB. Accessing CSA requires to be registered to enable user profiles and CSA accounts more than 1,500 users. CSA provides unique tools for visualizing its data including - on-demand particle distribution functions visualization - fast data browsing with more than 15TB of pre-generated plots - inventory plots It also offers command line capabilities (e.g. data access via Matlab or IDL softwares, data streaming). Despite its reliability, users can only request data for a specific time period while scientists often focus on specific regions or data signatures. For these reasons, a data-mining tool is being developed to do just that. It offers an interface to select data based not only on a time period but on various criteria including: key physical parameters, regions of space and spacecraft constellation geometry. The output of this tool is a

  19. Geometric tools for solving the FDI problem for linear periodic discrete-time systems

    NASA Astrophysics Data System (ADS)

    Longhi, Sauro; Monteriù, Andrea

    2013-07-01

    This paper studies the problem of detecting and isolating faults in linear periodic discrete-time systems. The aim is to design an observer-based residual generator where each residual is sensitive to one fault, whilst remaining insensitive to the other faults that can affect the system. Making use of the geometric tools, and in particular of the outer observable subspace notion, the Fault Detection and Isolation (FDI) problem is formulated and necessary and solvability conditions are given. An algorithmic procedure is described to determine the solution of the FDI problem.

  20. Thermomagnetic convection in a ferrofluid layer exposed to a time-periodic magnetic field

    NASA Astrophysics Data System (ADS)

    Matura, P.; Lücke, M.

    2009-08-01

    We have investigated the influence of a time-periodic and spatially homogeneous magnetic field on the linear stability properties and on the nonlinear response of a ferrofluid layer heated from below and from above. A competition between stabilizing thermal and viscous diffusion and destabilizing buoyancy and Kelvin forces occurs. Floquet theory is used to determine the stability boundaries of the motionless conductive state for a harmonic and subharmonic response. Full numerical simulations with a finite difference method were made to obtain nonlinear convective states. The effect of low- and high-frequency modulation on the stability boundaries as well as on the nonlinear oscillations that may occur is investigated.

  1. Time series modelling of increased soil temperature anomalies during long period

    NASA Astrophysics Data System (ADS)

    Shirvani, Amin; Moradi, Farzad; Moosavi, Ali Akbar

    2015-10-01

    Soil temperature just beneath the soil surface is highly dynamic and has a direct impact on plant seed germination and is probably the most distinct and recognisable factor governing emergence. Autoregressive integrated moving average as a stochastic model was developed to predict the weekly soil temperature anomalies at 10 cm depth, one of the most important soil parameters. The weekly soil temperature anomalies for the periods of January1986-December 2011 and January 2012-December 2013 were taken into consideration to construct and test autoregressive integrated moving average models. The proposed model autoregressive integrated moving average (2,1,1) had a minimum value of Akaike information criterion and its estimated coefficients were different from zero at 5% significance level. The prediction of the weekly soil temperature anomalies during the test period using this proposed model indicated a high correlation coefficient between the observed and predicted data - that was 0.99 for lead time 1 week. Linear trend analysis indicated that the soil temperature anomalies warmed up significantly by 1.8°C during the period of 1986-2011.

  2. Periodic boundary conditions for long-time nonequilibrium molecular dynamics simulations of incompressible flows

    NASA Astrophysics Data System (ADS)

    Dobson, Matthew

    2014-11-01

    This work presents a generalization of the Kraynik-Reinelt (KR) boundary conditions for nonequilibrium molecular dynamics simulations. In the simulation of steady, homogeneous flows with periodic boundary conditions, the simulation box deforms with the flow, and it is possible for image particles to become arbitrarily close, causing a breakdown in the simulation. The KR boundary conditions avoid this problem for planar elongational flow and general planar mixed flow [T. A. Hunt, S. Bernardi, and B. D. Todd, J. Chem. Phys. 133, 154116 (2010)] through careful choice of the initial simulation box and by periodically remapping the simulation box in a way that conserves image locations. In this work, the ideas are extended to a large class of three-dimensional flows by using multiple remappings for the simulation box. The simulation box geometry is no longer time-periodic (which was shown to be impossible for uniaxial and biaxial stretching flows in the original work by Kraynik and Reinelt [Int. J. Multiphase Flow 18, 1045 (1992)]. The presented algorithm applies to all flows with nondefective flow matrices, and in particular, to uniaxial and biaxial flows.

  3. Symbolic dynamics of pulse transit time and heart period in children with upper airway obstruction.

    PubMed

    Baumert, Mathias; Kohler, Mark; Pamula, Yvonne; Immanuel, Sarah A

    2015-08-01

    Upper airway obstruction (UAO) is a relatively common condition during childhood that is characterized by periods of partial or complete upper airway closure, resulting in restless sleep. It has also been suggested that UAO triggers early cardiovascular changes that may predispose to an increased risk of developing cardiovascular diseases later in life. The aim of this study was to assess the temporal dynamics of heart period (HP) and pulse transit time (PTT) during quite, event-free periods of sleep in children with UAO (n = 40) and matched healthy controls. The dynamics of HP and PTT were symbolized based on the sextiles of their distribution and words of length three were formed and classified into four types based on their patterns. Joint symbolic dynamics represent the concomitant occurrence of words in HP and PTT. Children with UAO showed a significantly increased frequency in word types of monotonously increasing and decreasing HP and PTT as well as joint dynamics across all stages of sleep. The dynamics of HP showed a marked sleep stage dependence, while PTT dynamics appeared to be relatively unaffected. In conclusion, cardiovascular dynamics are altered in children with UAO during scored event-free sleep, indicative of frequent bursts in sympathetic nervous system activity, possibly reflecting subcortical arousal responses to brief and subtle increases in UAO. PMID:26736629

  4. Respiratory rate: measurement of variability over time and accuracy at different counting periods.

    PubMed Central

    Simoes, E A; Roark, R; Berman, S; Esler, L L; Murphy, J

    1991-01-01

    The respiratory rates/minute of 97 children were monitored every 10-15 minutes over one hour, by an observer and by pneumogram, at which times two 30 second and one 60 second counts were obtained. The children were under 5 years of age with lower respiratory tract infections (n = 20), upper respiratory tract infections (n = 34), or controls without acute respiratory infection (n = 43). The difference between respiratory rate count determined simultaneously by observation and pneumogram in relation to their mean count was analysed for the 60 second counting period, 30 plus 30 second period, and the 30 second period doubled. The mean difference for the 60 second period was 1.79, for the 30 plus 30 second period 1.42, and for the 30 second period doubled 1.72. The variability between respiratory rate counts determined by observation and pneumogram was significantly lower in counts obtained when the subject was sleeping and higher when agitated compared with obtaining a count when the subject was awake and calm or feeding. The variability was also significantly lower in subjects with lower respiratory tract infections compared with those with upper respiratory tract infections and control subjects without respiratory symptoms. In the same patient, over the one hour, 50% of the 60 second counts varied by up to 14 breaths/minute and 75% by up to 21 breaths/minute. The least variability was seen in children with a lower respiratory tract infection, who tended to maintain their rapid breathing in contrast to those with an upper respiratory tract infection and controls without respiratory symptoms. About 10% of initial 30 second counts, 12% of 60 second, and 16% of initial and repeat 30 second attempts to obtain accurate counts failed. Failures occurred more frequently in children <2 months of age and those agitated. The data from this study suggest that one minute's counting either at a stretch or in two blocks of 30 second intervals is better than counting the respiratory

  5. Time-dependent Mott transition in the periodic Anderson model with nonlocal hybridization

    NASA Astrophysics Data System (ADS)

    Hofmann, Felix; Potthoff, Michael

    2016-08-01

    The time-dependent Mott transition in a periodic Anderson model with off-site, nearest-neighbor hybridization is studied within the framework of nonequilibrium self-energy functional theory. Using the two-site dynamical-impurity approximation, we compute the real-time dynamics of the optimal variational parameter and of different observables initiated by sudden quenches of the Hubbard-U and identify the critical interaction. The time-dependent transition is orbital selective, i.e., in the final state, reached in the long-time limit after the quench to the critical interaction, the Mott gap opens in the spectral function of the localized orbitals only. We discuss the dependence of the critical interaction and of the final-state effective temperature on the hybridization strength and point out the various similarities between the nonequilibrium and the equilibrium Mott transition. It is shown that these can also be smoothly connected to each other by increasing the duration of a U-ramp from a sudden quench to a quasi-static process. The physics found for the model with off-site hybridization is compared with the dynamical Mott transition in the single-orbital Hubbard model and with the dynamical crossover found for the real-time dynamics of the conventional Anderson lattice with on-site hybridization.

  6. Tracking rhythmicity in nonstationary quasi-periodic biomedical signals using adaptive time-varying covariance.

    PubMed

    Li, Dan; Jung, Ranu

    2002-07-01

    A time-varying covariance method for detecting and quantifying the evolution of rhythmicity (frequency) in persistently varying quasi-periodic nonstationary signals is presented. The basic method, evaluated using chirp signals, utilizes a shifting window of fixed length. A substantial reduction in estimation bias and variability are obtained by utilizing an adaptive window whose length is dependent on past frequency estimates. The adaptive window yields estimates that are comparable in accuracy to those obtained using high-resolution time-frequency representation but with lower computation requirements and the potential for on-line application. Finally, an example of the application of the method for analyzing a neural recording is also illustrated. PMID:11931864

  7. Spectral factorization in periodically time-varying systems and application to navigation problems.

    NASA Technical Reports Server (NTRS)

    Nishimura, T.

    1972-01-01

    Spectral factorization has been used previously to derive the steady-state solution of Kalman filtering equations without iteration for constant coefficient systems. The present work extends the spectral factorization algorithm to time-varying systems having periodic coefficient matrices for cases of both discrete and continuous systems. Time-consuming, expensive iterations of sequential covariance equations are not required to reach the final solution since this is an algebraic algorithm employing existing eigenvalue, eigenvector subroutines. The computer program incorporating the algorithm is suitable for sensitivity studies in formulating navigation and guidance strategies of low-thrust interplanetary missions. The determination of an optimum tracking pattern from an earth station is examined as an example.

  8. Nonlinear time-periodic models of the longitudinal flight dynamics of desert locusts Schistocerca gregaria

    PubMed Central

    Taylor, Graham K; Żbikowski, Rafał

    2005-01-01

    Previous studies of insect flight control have been statistical in approach, simply correlating wing kinematics with body kinematics or force production. Kinematics and forces are linked by Newtonian mechanics, so adopting a dynamics-based approach is necessary if we are to place the study of insect flight on its proper physical footing. Here we develop semi-empirical models of the longitudinal flight dynamics of desert locusts Schistocerca gregaria. We use instantaneous force–moment measurements from individual locusts to parametrize the nonlinear rigid body equations of motion. Since the instantaneous forces are approximately periodic, we represent them using Fourier series, which are embedded in the equations of motion to give a nonlinear time-periodic (NLTP) model. This is a proper mathematical generalization of an earlier linear-time invariant (LTI) model of locust flight dynamics, developed using previously published time-averaged versions of the instantaneous force recordings. We perform various numerical simulations, within the fitted range of the model, and across the range of body angles used by free-flying locusts, to explore the likely behaviour of the locusts upon release from the tether. Solutions of the NLTP models are compared with solutions of the nonlinear time-invariant (NLTI) models to which they reduce when the periodic terms are dropped. Both sets of models are unstable and therefore fail to explain locust flight stability fully. Nevertheless, whereas the measured forces include statistically significant harmonic content up to about the eighth harmonic, the simulated flight trajectories display no harmonic content above the fundamental forcing frequency. Hence, manoeuvre control in locusts will not directly reflect subtle changes in the higher harmonics of the wing beat, but must operate on a coarser time-scale. A state-space analysis of the NLTP models reveals orbital trajectories that are impossible to capture in the LTI and NLTI models

  9. Trajectories of maternal depression and offspring psychopathology at 6 years: 2004 Pelotas cohort study

    PubMed Central

    Matijasevich, Alicia; Murray, Joseph; Cooper, Peter J.; Anselmi, Luciana; Barros, Aluísio J.D.; Barros, Fernando C.; Santos, Iná S.

    2015-01-01

    Background Few studies have addressed the course and severity of maternal depression and its effects on child psychiatric disorders from a longitudinal perspective. This study aimed to identify longitudinal patterns of maternal depression and to evaluate whether distinct depression trajectories predict particular psychiatric disorders in offspring. Methods Cohort of 4231 births followed-up in the city of Pelotas, Brazil. Maternal depressive symptoms were assessed with the Edinburgh Postnatal Depression Scale (EPDS) at 3, 12, 24 and 48 months and 6 years after delivery. Psychiatric disorders in 6-year-old children were evaluated through the development and well-being assessment (DAWBA) instrument. Trajectories of maternal depression were calculated using a group-based modelling approach. Results We identified five trajectories of maternal depressive symptoms: a “low” trajectory (34.8%), a “moderate low” (40.9%), a “increasing” (9.0%), a “decreasing” (9.9%), and a “high-chronic” trajectory (5.4%). The probability of children having any psychiatric disorder, as well as both internalizing and externalizing problems, increased as we moved from the “low” to the “high-chronic” trajectory. These differences were not explained by maternal and child characteristics examined in multivariate analyses. Limitations Data on maternal depression at 3-months was available on only a sub-sample. In addition, we had to rely on maternal report of child’s behavior alone. Conclusions The study revealed an additive effect on child outcome of maternal depression over time. We identified a group of mothers with chronic and severe symptoms of depression throughout the first six years of the child life and for this group child psychiatric outcome was particularly compromised. PMID:25553403

  10. Period-independent novel circadian oscillators revealed by timed exercise and palatable meals

    PubMed Central

    Flôres, Danilo E. F. L.; Bettilyon, Crystal N.; Yamazaki, Shin

    2016-01-01

    The mammalian circadian system is a hierarchical network of oscillators organized to optimally coordinate behavior and physiology with daily environmental cycles. The suprachiasmatic nucleus (SCN) of the hypothalamus is at the top of this hierarchy, synchronizing to the environmental light-dark cycle, and coordinates the phases of peripheral clocks. The Period genes are critical components of the molecular timekeeping mechanism of these clocks. Circadian clocks are disabled in Period1/2/3 triple mutant mice, resulting in arrhythmic behavior in constant conditions. We uncovered rhythmic behavior in this mutant by simply exposing the mice to timed access to a palatable meal or running wheel. The emergent circadian behavior rhythms free-ran for many cycles under constant conditions without cyclic environmental cues. Together, these data demonstrate that the palatable meal-inducible circadian oscillator (PICO) and wheel-inducible circadian oscillator (WICO) are generated by non-canonical circadian clocks. Entrainment of these novel oscillators by palatable snacks and timed exercise could become novel therapeutics for human conditions caused by disruptions of the circadian clocks. PMID:26904978

  11. Period-independent novel circadian oscillators revealed by timed exercise and palatable meals.

    PubMed

    Flôres, Danilo E F L; Bettilyon, Crystal N; Yamazaki, Shin

    2016-01-01

    The mammalian circadian system is a hierarchical network of oscillators organized to optimally coordinate behavior and physiology with daily environmental cycles. The suprachiasmatic nucleus (SCN) of the hypothalamus is at the top of this hierarchy, synchronizing to the environmental light-dark cycle, and coordinates the phases of peripheral clocks. The Period genes are critical components of the molecular timekeeping mechanism of these clocks. Circadian clocks are disabled in Period1/2/3 triple mutant mice, resulting in arrhythmic behavior in constant conditions. We uncovered rhythmic behavior in this mutant by simply exposing the mice to timed access to a palatable meal or running wheel. The emergent circadian behavior rhythms free-ran for many cycles under constant conditions without cyclic environmental cues. Together, these data demonstrate that the palatable meal-inducible circadian oscillator (PICO) and wheel-inducible circadian oscillator (WICO) are generated by non-canonical circadian clocks. Entrainment of these novel oscillators by palatable snacks and timed exercise could become novel therapeutics for human conditions caused by disruptions of the circadian clocks. PMID:26904978

  12. Association of Sugar-Sweetened Beverage Intake during Infancy with Dental Caries in 6-year-olds

    PubMed Central

    Lin, Mei; Onufrak, Stephen; Li, Ruowei

    2015-01-01

    To examine whether sugar-sweetened beverage (SSB) intake during infancy is associated with dental caries by age 6, a longitudinal analysis of 1,274 U.S. children was conducted using data from the 2005-2007 Infant Feeding Practices Study II and the 2012 Follow-up Study at 6 years of age. The exposure variables were maternal-reported SSB intakes during infancy (i.e., any SSB intake during infancy, age at SSB introduction during infancy, and average frequency of SSB intake during 10-12 months of age). The outcome variable was maternal-reported dental caries of their 6-year-old in his/her lifetime. Multivariable logistic regression analyses were used to calculate adjusted odds ratios (aOR) for associations of SSB intake during infancy with having dental caries among 6-year-olds after controlling for baseline characteristics of children and mothers and child's tooth brushing habits and sweet food intake at follow-up. Based on maternal recall, almost 40% of 6-year-olds had dental caries in their lifetime. Adjusted odds of having dental caries was significantly associated with higher frequency of SSB intake during 10-12 months (aOR=1.83 for ≥3 times/week, vs. none). Any SSB intake during infancy and age at SSB introduction during infancy were not associated with dental caries. In conclusion, frequent SSB intake during 10-12 months of age significantly increased the likelihood of having dental caries among 6-year-olds. Late infancy may be an important time for mothers to establish healthy beverage practices for their children. These findings can be used to inform efforts to reduce dental caries among children. PMID:25713788

  13. Variable Stars in the 3.6 Year DIRBE Near-Infrared Light Curve Archive

    NASA Astrophysics Data System (ADS)

    Kraemer, Kathleen E.; Price, S. D.; Smith, B. J.; Kuchar, T. A.; Mizuno, D. R.; Webb, J.

    2011-05-01

    The 3.6 year light curve archive created by Price et al. (2010) from the cryo+post-cryo Diffuse Infrared Background Experiment (DIRBE) mission contains a wealth of variable star information at 1.25, 2.2, 3.5, and 4.9 microns. Of the 2700 objects in the archive, over 500 show strong variability and another 75 show potential variability. We have combined visible observations obtained during the DIRBE extended mission with the infrared archive to investigate wavelength-dependent phase lags between the visible and the near-IR maxima, extending the study of Smith et al. (2006) to those stars with periods longer than the 300 day cryo mission. Of those 518 stars exhibiting strong near-infrared variability, 200 have visible light curves in the American Association of Variable Star Observers database during the DIRBE mission. Because viewing geometry for both the visible observers and DIRBE mission limited the opportunities for observing the stars, the light curves were inspected to determine if the peaks were defined well enough to determine phase lags among the five wavebands. For those objects that have sufficient data, we investigate a number of methods to best estimate the peaks and thus find the phase lags, if any. We have also examined the differences in phase dependence on variable type, e.g. Miras, SRa's, SRb's, and carbon stars. The DIRBE light curve data are available to the community through the Vizier service at the Centre de Donnees Astronomique de Strasbourg.

  14. 3.6 YEARS OF DIRBE NEAR-INFRARED STELLAR LIGHT CURVES

    SciTech Connect

    Price, Stephan D.; Kraemer, Kathleen E.; Kuchar, Thomas A.; Mizuno, Donald R. E-mail: smithbj@etsu.ed

    2010-10-15

    The weekly averaged near-infrared fluxes for 2652 stars were extracted from the cold and warm era all-sky maps of the Diffuse Infrared Background Experiment (DIRBE). Since the DIRBE program only archived the individual Calibrated Infrared Observations for the 10 month cold era mission, the weekly averaged fluxes were all that were available for the warm era. The steps required to extract stellar fluxes are described as are the adjustments that were necessary to correct the results for several systematic effects. The observations are at a cadence of once a week for 3.6 years ({approx}1300 days), providing continuous sampling on variable stars that span the entire period for the longest fundamental pulsators. The stars are divided into three categories: those with large amplitude of variability, smaller amplitude variables, and sources whose near-infrared brightness do not vary according to our classification criteria. We show examples of the results and the value of the added baseline in determining the phase lag between the visible and infrared.

  15. History of Animals using Isotope Records (HAIR): A 6-year dietary history of one family of African elephants

    PubMed Central

    Cerling, Thure E.; Wittemyer, George; Ehleringer, James R.; Remien, Christopher H.; Douglas-Hamilton, Iain

    2009-01-01

    The dietary and movement history of individual animals can be studied using stable isotope records in animal tissues, providing insight into long-term ecological dynamics and a species niche. We provide a 6-year history of elephant diet by examining tail hair collected from 4 elephants in the same social family unit in northern Kenya. Sequential measurements of carbon, nitrogen, and hydrogen isotope rations in hair provide a weekly record of diet and water resources. Carbon isotope ratios were well correlated with satellite-based measurements of the normalized difference vegetation index (NDVI) of the region occupied by the elephants as recorded by the global positioning system (GPS) movement record; the absolute amount of C4 grass consumption is well correlated with the maximum value of NDVI during individual wet seasons. Changes in hydrogen isotope ratios coincided very closely in time with seasonal fluctuations in rainfall and NDVI whereas diet shifts to relatively high proportions of grass lagged seasonal increases in NDVI by ≈2 weeks. The peak probability of conception in the population occurred ≈3 weeks after peak grazing. Spatial and temporal patterns of resource use show that the only period of pure browsing by the focal elephants was located in an over-grazed, communally managed region outside the protected area. The ability to extract time-specific longitudinal records on animal diets, and therefore the ecological history of an organism and its environment, provides an avenue for understanding the impact of climate dynamics and land-use change on animal foraging behavior and habitat relations. PMID:19365077

  16. Enhanced Transport of Passive Tracers In A Time Periodic Two-dimensional Flow

    NASA Astrophysics Data System (ADS)

    Boffetta, G.; Cencini, M.; Espa, S.; Musacchio, S.

    , investigating systems in which the second condition is violated is much more inter- esting. With this purpose, some experiments have shown how superdiffusion arises in a two-dimensional quasi-geostrophic (planetary-type) flow, where particles can jump for very long time in the same direction performing a Levy flight (Castiglione et al., 2001 ). Moreover, two recent papers (Vulpiani, 1998; Solomon, 2001) show how, also in very simple two-dimensional, time and space periodic cellular flows,anomalous diffusive behaviours can appear. In this paper we present an experimental study of transport in an electromagnetically forced time periodic two-dimensional flow. The flow is generated by applying an electromagnetic forcing on a thin layer of an elec- trolyte solution and reveals in a square grid of alternating vortices. Time dependence can be easily obtained by changing the time dependence of the electric fields. In par- ticular, considering certain values of the imposed oscillation frequencies, particles can display very long jump. Particle Tracking Velocimetry (PTV) is used to measure the flow field. This technique is the most suitable for studying dispersion phenomena in a Lagrangian framework allowing the direct evaluation of particle displacements and related quantities (Cenedese, Querzoli; 2000). Moreover, due to the characteristics of the analyzed flow and to the improvement of the tracking procedure, we have been able to track a great number of particles for time intervals greater than the charac- teristic time-scales of the flow. In order to characterize the time correlations we will evaluate the so-called jumps probabilities with memory which represent the probabil- ities to jump in a given direction conditioned to having experienced jumps in the same direction at previous times. Such statistics will revealed very useful and suitable for detecting the onset of the aforementioned correlations. 2

  17. Evolution of illustrations in anatomy: a study from the classical period in Europe to modern times.

    PubMed

    Ghosh, Sanjib Kumar

    2015-01-01

    Illustrations constitute an essential element of learning anatomy in modern times. However it required a significant evolutionary process spread over centuries, for illustrations to achieve the present status in the subject of anatomy. This review article attempts to outline the evolutionary process by highlighting on the works of esteemed anatomists in a chronological manner. Available literature suggests that illustrations were not used in anatomy during the classical period when the subject was dominated by the descriptive text of Galen. Guido da Vigevano was first to use illustrations in anatomy during the Late Middle Ages and this concept developed further during the Renaissance period when Andreas Vesalius pioneered in illustrations becoming an indispensable tool in conveying anatomical details. Toward later stages of the Renaissance period, Fabricius ab Aquapendente endeavored to restrict dramatization of anatomical illustrations which was a prevalent trend in early Renaissance. During the 18th century, anatomical artwork was characterized by the individual styles of prominent anatomists leading to suppression of anatomical details. In the 19th century, Henry Gray used illustrations in his anatomical masterpiece that focused on depicting anatomical structures and were free from any artistic style. From early part of the 20th century medical images and photographs started to complement traditional handmade anatomical illustrations. Computer technology and advanced software systems played a key role in the evolution of anatomical illustrations during the late 20th century resulting in new generation 3D image datasets that are being used in the 21st century in innovative formats for teaching and learning anatomy. PMID:25053471

  18. Periodic coupling strength-dependent multiple coherence resonance by time delay in Newman-Watts neuronal networks.

    PubMed

    Wu, Yanan; Gong, Yubing; Xu, Bo

    2013-12-01

    Recently, multiple coherence resonance induced by time delay has been observed in neuronal networks with constant coupling strength. In this paper, by employing Newman-Watts Hodgkin-Huxley neuron networks with time-periodic coupling strength, we study how the temporal coherence of spiking behavior and coherence resonance by time delay change when the frequency of periodic coupling strength is varied. It is found that delay induced coherence resonance is dependent on periodic coupling strength and increases when the frequency of periodic coupling strength increases. Periodic coupling strength can also induce multiple coherence resonance, and the coherence resonance occurs when the frequency of periodic coupling strength is approximately multiple of the spiking frequency. These results show that for periodic coupling strength time delay can more frequently optimize the temporal coherence of spiking activity, and periodic coupling strength can repetitively optimize the temporal coherence of spiking activity as well. Frequency locking may be the mechanism for multiple coherence resonance induced by periodic coupling strength. These findings imply that periodic coupling strength is more efficient for enhancing the temporal coherence of spiking activity of neuronal networks, and thus it could play a more important role in improving the time precision of information processing and transmission in neural networks. PMID:24060612

  19. Stochastic extinction of tumor cells due to synchronization effect through time periodic treatment in a tumor-immune interaction model

    NASA Astrophysics Data System (ADS)

    Aisu, Ryota; Horita, Takehiko

    The response to a time periodic treatment of the immunotherapy in a stochastic model of tumor-immune interaction is numerically investigated. Due to the effect of synchronization among the intrinsic oscillation and the treatment, an enhanced extinction of the tumor cells is observed. It suggests that compared with the static treatment, by controlling the period of the treatment, the time periodic treatment could be an effective way of treatment leading to tumor extinction.

  20. 40 CFR 270.215 - How are time periods in the requirements in this subpart and my RAP computed?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... requirements in this subpart and my RAP computed? 270.215 Section 270.215 Protection of Environment... HAZARDOUS WASTE PERMIT PROGRAM Remedial Action Plans (RAPs) Operating Under Your Rap § 270.215 How are time periods in the requirements in this subpart and my RAP computed? (a) Any time period scheduled to begin...

  1. 40 CFR 270.215 - How are time periods in the requirements in this subpart and my RAP computed?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... requirements in this subpart and my RAP computed? 270.215 Section 270.215 Protection of Environment... HAZARDOUS WASTE PERMIT PROGRAM Remedial Action Plans (RAPs) Operating Under Your Rap § 270.215 How are time periods in the requirements in this subpart and my RAP computed? (a) Any time period scheduled to begin...

  2. 40 CFR 270.215 - How are time periods in the requirements in this subpart and my RAP computed?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... requirements in this subpart and my RAP computed? 270.215 Section 270.215 Protection of Environment... HAZARDOUS WASTE PERMIT PROGRAM Remedial Action Plans (RAPs) Operating Under Your Rap § 270.215 How are time periods in the requirements in this subpart and my RAP computed? (a) Any time period scheduled to begin...

  3. 40 CFR 270.215 - How are time periods in the requirements in this subpart and my RAP computed?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... requirements in this subpart and my RAP computed? 270.215 Section 270.215 Protection of Environment... HAZARDOUS WASTE PERMIT PROGRAM Remedial Action Plans (RAPs) Operating Under Your Rap § 270.215 How are time periods in the requirements in this subpart and my RAP computed? (a) Any time period scheduled to begin...

  4. 40 CFR 270.215 - How are time periods in the requirements in this subpart and my RAP computed?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... requirements in this subpart and my RAP computed? 270.215 Section 270.215 Protection of Environment... HAZARDOUS WASTE PERMIT PROGRAM Remedial Action Plans (RAPs) Operating Under Your Rap § 270.215 How are time periods in the requirements in this subpart and my RAP computed? (a) Any time period scheduled to begin...

  5. 45 CFR 2526.40 - What is the time period during which an individual may use an education award?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false What is the time period during which an individual may use an education award? 2526.40 Section 2526.40 Public Welfare Regulations Relating to Public Welfare (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE ELIGIBILITY FOR AN EDUCATION AWARD § 2526.40 What is the time period during which...

  6. 41 CFR 302-8.203 - What is the authorized time period for extended storage of my HHG?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... time period for extended storage of my HHG? 302-8.203 Section 302-8.203 Public Contracts and Property Management Federal Travel Regulation System RELOCATION ALLOWANCES TRANSPORTATION AND STORAGE OF PROPERTY 8... Continental United States (OCONUS) § 302-8.203 What is the authorized time period for extended storage of...

  7. Sustained and transient attentional processes modulate neural predictors of memory encoding in consecutive time periods

    PubMed Central

    Padovani, Tullia; Koenig, Thomas; Eckstein, Doris; Perrig, Walter J

    2013-01-01

    Memory formation is commonly thought to rely on brain activity following an event. Yet, recent research has shown that even brain activity previous to an event can predict later recollection (subsequent memory effect, SME). In order to investigate the attentional sources of the SME, event-related potentials (ERPs) elicited by task cues preceding target words were recorded in a switched task paradigm that was followed by a surprise recognition test. Stay trials, that is, those with the same task as the previous trial, were contrasted with switch trials, which included a task switch compared to the previous trial. The underlying assumption was that sustained attention would be dominant in stay trials and that transient attentional reconfiguration processes would be dominant in switch trials. To determine the SME, local and global statistics of scalp electric fields were used to identify differences between subsequently remembered and forgotten items. Results showed that the SME in stay trials occurred in a time window from 2 to 1 sec before target onset, whereas the SME in switch trials occurred subsequently, in a time window from 1 to 0 sec before target onset. Both SMEs showed a frontal negativity resembling the topography of previously reported effects, which suggests that sustained and transient attentional processes contribute to the prestimulus SME in consecutive time periods. PMID:24381815

  8. A General Time-Periodic Driving Approach to Realize Topological Phases in Cold Atomic Systems

    PubMed Central

    Yan, Zhongbo; Li, Bo; Yang, Xiaosen; Wan, Shaolong

    2015-01-01

    For time-reversal symmetric cold atomic insulating systems, it is found that the usual driving approach based on electromagnetic field used in solid state systems loses its power to drive them from trivial regimes to topological regimes if the driven systems still hold time-reversal symmetry (TRS). For such systems, we point out that simply varying the optical lattice potential periodically provides a general and effective way to drive them into topological regimes without breaking their symmetries. Based on this approach, we find that the time-reversal symmetric Kane-Mele model can be effectively driven from the trivial phase to topological phases named as Floquet Quantum Spin Hall insulator. Due to the existence of two gaps in the Floquet system, this novel state of matter can stably host one or two pair of gapless helical states on the same boundary, which suggests this state is not a simple analog of the Quantum Spin Hall insulator. This new driving approach to a system without TRS is also investigated. PMID:26541611

  9. Dynamical generalized Hurst exponent as a tool to monitor unstable periods in financial time series

    NASA Astrophysics Data System (ADS)

    Morales, Raffaello; Di Matteo, T.; Gramatica, Ruggero; Aste, Tomaso

    2012-06-01

    We investigate the use of the Hurst exponent, dynamically computed over a weighted moving time-window, to evaluate the level of stability/instability of financial firms. Financial firms bailed-out as a consequence of the 2007-2008 credit crisis show a neat increase with time of the generalized Hurst exponent in the period preceding the unfolding of the crisis. Conversely, firms belonging to other market sectors, which suffered the least throughout the crisis, show opposite behaviors. We find that the multifractality of the bailed-out firms increase at the crisis suggesting that the multi fractal properties of the time series are changing. These findings suggest the possibility of using the scaling behavior as a tool to track the level of stability of a firm. In this paper, we introduce a method to compute the generalized Hurst exponent which assigns larger weights to more recent events with respect to older ones. In this way large fluctuations in the remote past are less likely to influence the recent past. We also investigate the scaling associated with the tails of the log-returns distributions and compare this scaling with the scaling associated with the Hurst exponent, observing that the processes underlying the price dynamics of these firms are truly multi-scaling.

  10. Sustained and transient attentional processes modulate neural predictors of memory encoding in consecutive time periods.

    PubMed

    Padovani, Tullia; Koenig, Thomas; Eckstein, Doris; Perrig, Walter J

    2013-07-01

    Memory formation is commonly thought to rely on brain activity following an event. Yet, recent research has shown that even brain activity previous to an event can predict later recollection (subsequent memory effect, SME). In order to investigate the attentional sources of the SME, event-related potentials (ERPs) elicited by task cues preceding target words were recorded in a switched task paradigm that was followed by a surprise recognition test. Stay trials, that is, those with the same task as the previous trial, were contrasted with switch trials, which included a task switch compared to the previous trial. The underlying assumption was that sustained attention would be dominant in stay trials and that transient attentional reconfiguration processes would be dominant in switch trials. To determine the SME, local and global statistics of scalp electric fields were used to identify differences between subsequently remembered and forgotten items. Results showed that the SME in stay trials occurred in a time window from 2 to 1 sec before target onset, whereas the SME in switch trials occurred subsequently, in a time window from 1 to 0 sec before target onset. Both SMEs showed a frontal negativity resembling the topography of previously reported effects, which suggests that sustained and transient attentional processes contribute to the prestimulus SME in consecutive time periods. PMID:24381815

  11. Multi Band Insar Analysis of Subsidence Development Based on the Long Period Time Series

    NASA Astrophysics Data System (ADS)

    Çomut, F. C.; Ustun, A.; Lazecky, M.; Aref, M. M.

    2015-12-01

    The SAR Interferometry (InSAR) application has shown great potential in monitoring of land terrain changes and in detection of land deformations such as subsidence. Longer time analysis can lead to understand longer trends and changes. Using different bands of SAR satellite (C- from ERS 1-2 and Envisat, L- from ALOS) over the study area, we achieve knowledge of movements in long-term and evaluation of its dynamic changes within observed period of time. Results from InSAR processing fit with the position changes in vertical direction based on GPS network established over the basin as an effective geodetic network. Time series (StaMPS PS+SB) of several points over Çumra County in eastern part of Konya City show a general trend of the deformation that is expected to be approximately between -13 to -17 mm/year. Northern part of Karaman is affected by faster subsidence, borders of the subsidence trough were identified from Envisat. Presenting InSAR results together with GIS information about locations and time of occurrence of sudden subsidence, urban/industrial growth in time and climate changes helps in better understanding of the situation. This way, the impact of natural and man-made changes will be shown for urban planning thanks to InSAR and GIS comparisons with hydrogeological modeling. In this study we present results of differential and multitemporal InSAR series using different bands and GIS conjunction associated with seasonal and temporal groundwater level changes in Konya Closed Basin.

  12. On the periodicity of symbolic observations of piecewise smooth discrete-time systems

    NASA Technical Reports Server (NTRS)

    Ramadge, Peter J.

    1990-01-01

    A study is made of the behavior of discrete-time systems composed of a set of smooth transition maps coupled by a quantized feedback function. The feedback function partitions the state space into disjoint regions and assigns a smooth transition function to each region. The main result is that under a constraint on the norm of the derivative of the transition maps, a bounded state trajectory with limit points in the interior of the switching regions leads to a region index sequence that is eventually periodic. Under these assumptions, it is shown that eventually the feedback function is determined by a finite state automaton. A similar result is proved in the case of finite state dynamic feedback.

  13. Removing tidal-period variations from time-series data using low-pass digital filters

    USGS Publications Warehouse

    Walters, Roy A.; Heston, Cynthia

    1982-01-01

    Several low-pass, digital filters are examined for their ability to remove tidal Period Variations from a time-series of water surface elevation for San Francisco Bay. The most efficient filter is the one which is applied to the Fourier coefficients of the transformed data, and the filtered data recovered through an inverse transform. The ability of the filters to remove the tidal components increased in the following order: 1) cosine-Lanczos filter, 2) cosine-Lanczos squared filter; 3) Godin filter; and 4) a transform fitter. The Godin fitter is not sufficiently sharp to prevent severe attenuation of 2–3 day variations in surface elevation resulting from weather events.

  14. Controllability discrepancy and irreducibility/reducibility of Floquet factorisations in linear continuous-time periodic systems

    NASA Astrophysics Data System (ADS)

    Zhou, Jun; Lu, Xinbiao; Qian, Huimin

    2016-09-01

    The paper reports interesting but unnoticed facts about irreducibility (resp., reducibility) of Flouqet factorisations and their harmonic implication in term of controllability in finite-dimensional linear continuous-time periodic (FDLCP) systems. Reducibility and irreducibility are attributed to matrix logarithm algorithms during computing Floquet factorisations in FDLCP systems, which are a pair of essential features but remain unnoticed in the Floquet theory so far. The study reveals that reducible Floquet factorisations may bring in harmonic waves variance into the Fourier analysis of FDLCP systems that in turn may alter our interpretation of controllability when the Floquet factors are used separately during controllability testing; namely, controllability interpretation discrepancy (or simply, controllability discrepancy) may occur and must be examined whenever reducible Floquet factorisations are involved. On the contrary, when irreducible Floquet factorisations are employed, controllability interpretation discrepancy can be avoided. Examples are included to illustrate such observations.

  15. Intercomparison of UT1 measurements during the MERIT campaign period. [Universal Time

    NASA Technical Reports Server (NTRS)

    Spieth, M. A.; Eubanks, T. M.; Steppe, J. A.

    1986-01-01

    Universal time (UT1) measurements obtained using VLBI, lunar laser ranging (LLR), and BIH optical astronomy are compared. The JPL Kalman filter for the earth rotation and the polar motion is utilized to smooth one data set or combine data sets for intercomparison. The differences between raw UT1 data and independently smoothed data are employed to assess the accuracy of the measured series and the sufficiency of the error budget. Systematic errors in periodic signatures and length of day estimates are analyzed. The data reveal that the techniques of LLR and VLBI agree to within their formal errors. It is determined that the residual error for the LLR is too large and the residual error estimated for the BIH data is too small.

  16. Efficiency, Power and Period of a model quantum heat engine working in a finite time

    NASA Astrophysics Data System (ADS)

    Bekele, Mulugeta; Dima, Tolasa A.; Alemye, Mekuannent; Chegeno, Warga

    We take a spin-half quantum particle undergoing Carnot type cyclic process in a finite time assisted by two heat reservoirs and an external magnetic field. We find that the power of the heat engine is maximum at a particular period of the cyclic process and efficiency at the maximum power is at least half of the Carnot efficiency. We further apply the Omega-criterion for a figure of merit representing a compromise between useful power and lost power determining the corresponding efficiency for the optimization criterion to be at least three fourth of the Carnot efficiency. The authers are thankful to the International Science programme, IPS, Uppsala, Sweden for their support to our research lab.

  17. Network news coverage of obesity in two time periods: an analysis of issues, sources, and frames.

    PubMed

    Gearhart, Sherice; Craig, Clay; Steed, Chaille

    2012-01-01

    Obesity is an epidemic plaguing American society. The current study adds to a growing body of framing research as it examines the portrayal of obesity on television network news in two 5-year time periods, 1995-1999 and 2005-2009. Through content analysis of TV news transcripts from three networks (ABC, NBC, and CBS), this study analyzed episodic-thematic frames, issues, and sources. Results revealed the amount of obesity-related news coverage increased along with thematically framed stories. The use of politicians, affected others, supporters, and others as sources increased, but experts and those struggling with obesity remained primary sources. Changes in the proportion of issues discussed revealed significant decreases in the discussion of genetic causes and personal stories. Results reflect the societal impact of obesity and indicate the ways in which obesity is perceived by the public through network news. Findings provide insight for media advocacy opportunities and contribute to research on framing and obesity. PMID:22236324

  18. Low-thrust roundtrip trajectories to Mars with one-synodic-period repeat time

    NASA Astrophysics Data System (ADS)

    Okutsu, Masataka; Landau, Damon F.; Rogers, Blake A.; Longuski, James M.

    2015-05-01

    Cycler trajectories-both ballistic and powered-are reported in the literature in which there are two-vehicle, three-vehicle, and four-vehicle cases. Such trajectories permit the installation of cycler vehicles which provide safe and comfortable living conditions for human space travel between Earth and Mars during every synodic opportunity. The question the present paper answers is a logical, obvious one: Does a single-vehicle, one-synodic-period cycler exist? The answer is yes: such a trajectory can be flown-but only with a high-power electric propulsion system. In our example, it is found that "stopover" trajectories that spend 30 days in orbit about Earth and 30 days about Mars, and return astronauts to Earth in one synodic period require a 90-t power generator with a power level of 11 MWe. Fortuitously, and in lieu of using chemical propulsion, the high power level of the electric propulsion system would also be effective in hauling the cargo payload via a spiral trajectory about the Earth. But because one synodic period is not enough for the cycler vehicle to fly both the interplanetary trajectories and the Earth-spiral trajectories, we suggest developing two nuclear power generators, which could alternate flying the interplanetary trajectories and the Earth-spiral trajectories. Once these power generators are launched and begin operating in space, the mass requirement in seven subsequent missions (over a period of 15 years beginning in 2022) would be modest at 250-300 metric tons to low-Earth orbit per mission. Thus two cargo launches of NASA's Space Launch System and one crew launch of the Falcon Heavy, for example, would be adequate to maintain support for each consecutive mission. Although we propose developing two sets of electric propulsion systems to account for the Earth-spiral phases, only one vehicle is flown on a heliocentric trajectory at any given time. Thus, our low-thrust stopover cycler with zero encounter velocities falls into a category of a

  19. Spectral analysis of radial Dirac operators in the Kerr-Newman metric and its applications to time-periodic solutions

    NASA Astrophysics Data System (ADS)

    Winklmeier, Monika; Yamada, Osanobu

    2006-10-01

    We investigate the existence of time-periodic solutions of the Dirac equation in the Kerr-Newman background metric. To this end, the solutions are expanded in a Fourier series with respect to the time variable t, and the Chandrasekhar separation ansatz is applied so that the question of existence of a time-periodic solution is reduced to the solvability of a certain coupled system of ordinary differential equations. First, we prove the already known result that there are no time-periodic solutions in the nonextreme case. Then, it is shown that in the extreme case for fixed black hole data there is a sequence of particle masses (mN)NɛN for which a time-periodic solution of the Dirac equation does exist. The period of the solution depends only on the data of the black hole described by the Kerr-Newman metric.

  20. Development and validation of a frontal impact 6-year-old occupant and wheelchair computer model.

    PubMed

    Ha, DongRan; Bertocci, Gina; Jategaonkar, Rohit

    2007-01-01

    Many children with disabilities use their wheelchair as a vehicle seat when traveling. To date, few studies have focused on pediatric wheelchair users in transit. A computer model representing a manual pediatric wheelchair seated with a Hybrid III 6-year-old anthropomorphic test device subjected to a 20-g/48-kph (30-mph) frontal crash was developed in MADYMO. The wheelchair was secured using a 4-point tiedown system, and the occupant was restrained using a 3-point belt system. The time history profiles of the computer model were tuned to those of the sled tests. The peak value for key variables was compared between the sled tests and the model. To evaluate model variable time histories, Pearson's correlation coefficients (r) between the sled test and the model outcome measures were determined. The correlation coefficients ranged from .86 to .95, with an average r of .91. This indicates that there are "high" correlations between the model and sled tests across all variables. The pediatric wheelchair model developed and validated in this study will provide a foundation for studying the response of a manual pediatric wheelchair in frontal impacts and associated injury risks for pediatric wheelchair users. PMID:18335711

  1. Time periods of GSR particles deposition after discharge-final results.

    PubMed

    Fojtásek, Lubor; Kmjec, Tomás

    2005-10-29

    The elemental objects of the research study are: determination of time periods corresponding to gunshot residue particles (GSR) deposition after the shot from selected pistols and a revolver, and evaluation of the deposited particles number. For several shooting experiments were used a pistol CZ model 85, caliber 9 mm Luger with common ammunition 9 mm Luger FMJ Sellier & Bellot, a pistol CZ model 70, caliber 7.65 mm Browning (32 ACP) with common 7.65 mm Browning FMJ Sellier & Bellot ammunition and a revolver S&W Modell 60, barell length 2-1/8'', cal. .38 Special with common Sellier&Bellot (FMJ) ammunition. The results of the study have indicated the behavior of GSR particles deposited after a single discharge. The overall time interval of GSR particles deposition and the number of deposited particles with the above mentioned arms and ammunition were established. The results can potentially be used for clarifying the situation at crime scenes and for subsequent interpretation of GSR evidential value in caseworks. PMID:16139100

  2. The timing of vortex shedding in a cylinder wake imposed by periodic inflow perturbations

    NASA Astrophysics Data System (ADS)

    Konstantinidis, E.; Balabani, S.; Yianneskis, M.

    2005-10-01

    The interaction of vortex shedding from a circular cylinder with an inflow which has low-amplitude periodic velocity oscillations (perturbations) superimposed upon it, was investigated experimentally by means of particle image velocimetry. The experiments were made at three perturbation frequencies across the lock-on range in which the vortex shedding frequency is synchronized with the subharmonic of the imposed frequency. The basic wake pattern in this range is antisymmetric vortex shedding, i.e. the familiar 2S mode. The timing of vortex shedding is defined with respect to the cross-flow oscillation of the wake which is found to play a critical role. Quantitative analysis of the phase-referenced patterns of vorticity distribution in the wake shows that a vortex is actually shed from the cylinder when the cross-flow oscillation of the wake is strongest, marked by a sudden drop in the computed vortex strength. At the middle of the lock-on range, shedding occurs near the minimum inflow velocity in the cycle or, equivalently, during the forward stroke of a cylinder oscillating in-line with the flow. It is argued that the imposed timing of vortex shedding relative to the cylinder motion induces a negative excitation from the fluid, which might explain why the in-line response of a freely vibrating cylinder exhibits two positive excitation regions separated by the lock-on region found in forced oscillations.

  3. Estimating interevent time distributions from finite observation periods in communication networks

    NASA Astrophysics Data System (ADS)

    Kivelä, Mikko; Porter, Mason A.

    2015-11-01

    A diverse variety of processes—including recurrent disease episodes, neuron firing, and communication patterns among humans—can be described using interevent time (IET) distributions. Many such processes are ongoing, although event sequences are only available during a finite observation window. Because the observation time window is more likely to begin or end during long IETs than during short ones, the analysis of such data is susceptible to a bias induced by the finite observation period. In this paper, we illustrate how this length bias is born and how it can be corrected without assuming any particular shape for the IET distribution. To do this, we model event sequences using stationary renewal processes, and we formulate simple heuristics for determining the severity of the bias. To illustrate our results, we focus on the example of empirical communication networks, which are temporal networks that are constructed from communication events. The IET distributions of such systems guide efforts to build models of human behavior, and the variance of IETs is very important for estimating the spreading rate of information in networks of temporal interactions. We analyze several well-known data sets from the literature, and we find that the resulting bias can lead to systematic underestimates of the variance in the IET distributions and that correcting for the bias can lead to qualitatively different results for the tails of the IET distributions.

  4. Local time distributions of repetition periods for rising tone lower band chorus waves in the magnetosphere

    NASA Astrophysics Data System (ADS)

    Shue, Jih-Hong; Hsieh, Yi-Kai; Tam, Sunny W. Y.; Wang, Kaiti; Fu, Hui Shan; Bortnik, Jacob; Tao, Xin; Hsieh, Wen-Chieh; Pi, Gilbert

    2015-10-01

    Whistler mode chorus waves generally occur outside the plasmapause in the magnetosphere. The most striking feature of the waves is their occurrence in discrete elements. One of the parameters that describe the discrete elements is the repetition period (Trp), the time between consecutive elements. The Trp has not been studied statistically before. We use high-resolution waveform data to derive distributions of Trp for different local times. We find that the average Trp for the nightside (0.56 s) and dawnside (0.53 s) are smaller than those for the dayside (0.81 s) and duskside (0.97 s). Through a comparison with the background plasma and magnetic fields, we also find that the total magnetic field and temperature are the main controlling factors that affect the variability of Trp. These results are important for understanding the generation mechanism of chorus and choosing parameters in simulations that model the acceleration and loss of electrons by wave-particle interactions.

  5. The Effects of Time-Periodic Shear on a Diffusion Flame Anchored to a Model Propellant

    NASA Astrophysics Data System (ADS)

    Isfahani, Amir H. G.; Zhang, Ju; Jackson, Thomas L.

    2008-11-01

    Propellants of solid rocket motors are subject to intense time-dependent shear flows and the response of the combustion field to these flows is of fundamental interest. Erosive burning (EB), the enhanced regression rate that can arise due to these flows, affects the performance of the solid rocket motor: the specific-impulse history. It is generally agreed that EB results from an increased heat transfer to the surface. The geometry is that of two quarter-planes of ammonium perchlorate (AP) and binder (or a blend of AP/binder). Three step kinetics is considered: AP decomposition and two diffusion flames, one between the virgin AP gases and binder and one between AP decomposed gases and binder. Gas and solid phases are coupled and temperature along the surface as well as the burn rate is solved for. We present an estimation of the shear parameters as a function of the motor size using a 2D planar periodic rocket (PPR) analysis without resorting to fully time-dependent three-dimensional turbulent simulations. These parameters are then used to study the change in the heat flux to the surface and the burn rate. It is shown that the burn rate is increased by more than two folds for larger amplitudes and frequencies.

  6. Growth mechanism of photoreduced silver nanostructures on periodically proton exchanged lithium niobate: Time and concentration dependence

    SciTech Connect

    Craig Carville, N.; Denning, Denise; Rodriguez, Brian J.; Manzo, Michele; Gallo, Katia

    2013-05-14

    Photodeposition of metallic nanostructures onto ferroelectric surfaces, which have been chemically patterned using a proton exchange process, has recently been demonstrated. By varying the molar concentration of the AgNO{sub 3} solution and the illumination time, one can determine the initial nucleation sites, control the rate of nucleation and the height of silver nanostructures formed, and study the mechanisms by which these processes occurs. The nanoparticles are found to deposit preferentially in the boundary between ferroelectric and proton exchanged regions, in an area proton exchanged via lateral diffusion under the masking layer used for chemical patterning, consistent with our previous results. Using a short illumination time (3 min), we are able to determine that the initial nucleation of the silver nanostructure, having a width of 0.17 {+-} 0.02 {mu}m and a height of 1.61 {+-} 0.98 nm, occurs near the edge of the reactive ion etched area within this lateral diffusion region. Over longer illumination times (15 min), we find that the silver deposition has spread to a width of 1.29 {+-} 0.06 {mu}m, extending across the entire lateral diffusion region. We report that at a high molar concentration of AgNO{sub 3} (10{sup -2} M), the amount of silver deposition for 5 min UV illumination is greater (2.88 {+-} 0.58 nm) compared to that at low (10{sup -4} M) concentrations (0.78 {+-} 0.35 nm), however, this is not the case for longer time periods. With increasing illumination time (15 min), experiments at 10{sup -4} M had greater overall deposition, 6.90 {+-} 1.52 nm, compared to 4.50 {+-} 0.76 nm at 10{sup -2} M. For longer exposure times (30 min) at 10{sup -2} M, the nanostructure height is 4.72 {+-} 0.59 nm, suggesting a saturation in the nanostructure height. The results are discussed in terms of the electric double layer that forms at the crystal surface. There is an order of magnitude difference between the Debye lengths for 10{sup -2} and 10{sup -4} M

  7. Ozone variability in the troposphere and the stratosphere from the first 6 years of IASI observations (2008-2013)

    NASA Astrophysics Data System (ADS)

    Wespes, Catherine; Hurtmans, Daniel; Emmons, Louisa K.; Safieddine, Sarah; Clerbaux, Cathy; Edwards, David P.; Coheur, Pierre-François

    2016-05-01

    In this paper, we assess how daily ozone (O3) measurements from the Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp-A platform can contribute to the analyses of the processes driving O3 variability in the troposphere and the stratosphere and, in the future, to the monitoring of long-term trends. The temporal evolution of O3 during the first 6 years of IASI (2008-2013) operation is investigated with multivariate regressions separately in four different layers (ground-300, 300-150, 150-25, 25-3 hPa), by adjusting to the daily time series averaged in 20° zonal bands, seasonal and linear trend terms along with important geophysical drivers of O3 variation (e.g. solar flux, quasi-biennial oscillation (QBO)). The regression model is shown to perform generally very well with a strong dominance of the annual harmonic terms and significant contributions from O3 drivers, in particular in the equatorial region where the QBO and the solar flux contribution dominate. More particularly, despite the short period of the IASI data set available up to now, two noticeable statistically significant apparent trends are inferred from the daily IASI measurements: a positive trend in the upper stratosphere (e.g. 1.74 ± 0.77 DU year-1 between 30 and 50° S), which is consistent with other studies suggesting a turnaround for stratospheric O3 recovery, and a negative trend in the troposphere at the mid-latitudes and high northern latitudes (e.g. -0.26 ± 0.11 DU year-1 between 30 and 50° N), especially during summer and probably linked to the impact of decreasing ozone precursor emissions. The impact of the high temporal sampling of IASI on the uncertainty in the determination of O3 trend has been further explored by performing multivariate regressions on IASI monthly averages and on ground-based Fourier transform infrared (FTIR) measurements.

  8. Almost periodic solutions for a memristor-based neural networks with leakage, time-varying and distributed delays.

    PubMed

    Jiang, Ping; Zeng, Zhigang; Chen, Jiejie

    2015-08-01

    In this paper, we study the existence and global exponential stability of almost periodic solution for memristor-based neural networks with leakage, time-varying and distributed delays. Using a new Lyapunov function method, we prove that this delayed neural network has a unique almost periodic solution, which is globally exponentially stable. Moreover, the obtained conclusion on the almost periodic solution is applied to prove the existence and stability of periodic solution (or equilibrium point) for this delayed neural network with periodic coefficients (or constant coefficients). PMID:25978771

  9. Mastery of Fundamental Movement Skills among 6-Year-Old Flemish Pre-School Children

    ERIC Educational Resources Information Center

    Vandaele, Bart; Cools, Wouter; de Decker, Steve; de Martelaer, Kristine

    2011-01-01

    The purpose of this study was to assess mastery of Fundamental Movement Skills (FMS) in 6- to 6.5-year-old Flemish pre-school children. The subjects were 236 6-year-old children (138 boys, 98 girls; mean age 6 years 2.4 months, SD 2.4). Children were individually assessed with the Motoriktest fur Vier- bis Sechsjahrige Kinder (MOT 4-6) in four…

  10. The last interglacial period on the Pacific Coast of North America: Timing and paleoclimate

    USGS Publications Warehouse

    Muhs, D.R.; Simmons, K.R.; Kennedy, G.L.; Rockwell, T.K.

    2002-01-01

    New, high-precision U-series ages of solitary corals (Balanophyllia elegans) coupled with molluscan faunal data from marine terraces on the Pacific Coast of North America yield information about the timing and warmth of the last interglacial sea-level highstand. Balanophyllia elegans takes up U in isotopic equilibrium with seawater during growth and shortly after death. Corals from the second terrace on San Clemente Island (offshore southern California), the third terrace on Punta Banda (on the Pacific Coast of northern Baja California), and the Discovery Point Formation on Isla de Guadalupe (in the Pacific Ocean offshore Baja California) date to the peak of the last interglacial period and have U-series ages ranging from ca. 123 to 114 ka. The first terrace on Punta Banda has corals with ages ranging from ca. 83 to 80 ka, which corresponds to a sea-level highstand formed in the late last interglacial period. U-series analyses of corals from the Cayucos terrace (central California) and the Nestor terrace at Point Loma (southern California) show that these fossils have evidence of open-system history, similar to what has been reported by other workers for the same localities. Nevertheless, a model of continuous, secondary U and Th uptake shows that two ages of corals are likely present at these localities, representing the ca. 105 and ca. 120 ka sea-level highstands reported elsewhere. U-series ages of last interglacial corals from the Pacific Coast overlap with, but are on average younger than the ages of corals from Barbados, the Bahamas, and Hawaii. This age difference is explained by the nature of the geomorphic response to sea-level change: fringing or barrier reefs on low-latitude coastlines have an accretionary growth style that keeps pace with rising sea level, whether on a tectonically rising or stable coastline. In contrast, midlatitude, high-energy coastlines are sites of platform cutting during the early part of a sea-level high stand and terrace

  11. Time-Based Measurement of Personal Mite Allergen Bioaerosol Exposure over 24 Hour Periods.

    PubMed

    Tovey, Euan R; Liu-Brennan, Damien; Garden, Frances L; Oliver, Brian G; Perzanowski, Matthew S; Marks, Guy B

    2016-01-01

    Allergic diseases such as asthma and rhinitis are common in many countries. Globally the most common allergen associated with symptoms is produced by house dust mites. Although the bed has often been cited as the main site of exposure to mite allergens, surprisingly this has not yet been directly established by measurement due to a lack of suitable methods. Here we report on the development of novel methods to determine the pattern of personal exposure to mite allergen bioaerosols over 24-hour periods and applied this in a small field study using 10 normal adults. Air was sampled using a miniature time-based air-sampler of in-house design located close to the breathing zone of the participants, co-located with a miniature time-lapse camera. Airborne particles, drawn into the sampler at 2L/min via a narrow slot, were impacted onto the peripheral surface of a disk mounted on the hour-hand of either a 12 or 24 hour clock motor. The impaction surface was either an electret cloth, or an adhesive film; both novel for these purposes. Following a review of the time-lapse images, disks were post-hoc cut into subsamples corresponding to eight predetermined categories of indoor or outdoor location, extracted and analysed for mite allergen Der p 1 by an amplified ELISA. Allergen was detected in 57.2% of the total of 353 subsamples collected during 20 days of sampling. Exposure patterns varied over time. Higher concentrations of airborne mite allergen were typically measured in samples collected from domestic locations in the day and evening. Indoor domestic Der p 1 exposures accounted for 59.5% of total exposure, whereas total in-bed-asleep exposure, which varied 80 fold between individuals, accounted overall for 9.85% of total exposure, suggesting beds are not often the main site of exposure. This study establishes the feasibility of novel methods for determining the time-geography of personal exposure to many bioaerosols and identifies new areas for future technical

  12. Time-Based Measurement of Personal Mite Allergen Bioaerosol Exposure over 24 Hour Periods

    PubMed Central

    Tovey, Euan R.; Liu-Brennan, Damien; Garden, Frances L.; Oliver, Brian G.; Perzanowski, Matthew S.; Marks, Guy B.

    2016-01-01

    Allergic diseases such as asthma and rhinitis are common in many countries. Globally the most common allergen associated with symptoms is produced by house dust mites. Although the bed has often been cited as the main site of exposure to mite allergens, surprisingly this has not yet been directly established by measurement due to a lack of suitable methods. Here we report on the development of novel methods to determine the pattern of personal exposure to mite allergen bioaerosols over 24-hour periods and applied this in a small field study using 10 normal adults. Air was sampled using a miniature time-based air-sampler of in-house design located close to the breathing zone of the participants, co-located with a miniature time-lapse camera. Airborne particles, drawn into the sampler at 2L/min via a narrow slot, were impacted onto the peripheral surface of a disk mounted on the hour-hand of either a 12 or 24 hour clock motor. The impaction surface was either an electret cloth, or an adhesive film; both novel for these purposes. Following a review of the time-lapse images, disks were post-hoc cut into subsamples corresponding to eight predetermined categories of indoor or outdoor location, extracted and analysed for mite allergen Der p 1 by an amplified ELISA. Allergen was detected in 57.2% of the total of 353 subsamples collected during 20 days of sampling. Exposure patterns varied over time. Higher concentrations of airborne mite allergen were typically measured in samples collected from domestic locations in the day and evening. Indoor domestic Der p 1 exposures accounted for 59.5% of total exposure, whereas total in-bed-asleep exposure, which varied 80 fold between individuals, accounted overall for 9.85% of total exposure, suggesting beds are not often the main site of exposure. This study establishes the feasibility of novel methods for determining the time-geography of personal exposure to many bioaerosols and identifies new areas for future technical

  13. An overview of new insights from 6 years of salinity data from SMOS mission

    NASA Astrophysics Data System (ADS)

    Nicolas, R.

    2015-12-01

    Measurements of salt held in surface seawater are becoming ever-more important for oceanographers and climatologists to gain a deeper understanding of ocean circulation and Earth's water cycle. ESA's SMOS mission is proving essential for this aim. Launched in 2009, SMOS has provided the longest continuous record (now ~6 years) of sea-surface salinity measurements from space. The salinity of surface seawater is controlled largely by the balance between evaporation and precipitation, but freshwater from rivers and the freezing and melting of ice also cause changes in concentrations. Along with temperature, salinity drives ocean circulation - the thermohaline circulation - which, in turn, plays a key role in the global climate. With a wealth of salinity data from SMOS now in hand complemented by measurements from the NASA-CONAE Aquarius satellite, which uses a different measuring technique. In this talk we shall provide an overview of how the SMOS mission - now celebrating 6 years in orbit - is providing detailed global measurements of SSS. An ensemble of key ocean processes for climate and biochemistry can now be determined and monitored for the first time from space : the detailed salinity structure of tropical instability waves along the equator and the salt exchanged across major oceanic current fronts, the occurrences of large-scale salinity anomalies in the Pacific and Indian oceans related to important climate indexes are also well-evidenced in the six year-long data. In addition, the dispersal of freshwater into the ocean from the major large tropical rivers (Amazon, Orinoco and Congo), their impact on tropical cyclone (TC) intensification and the oceanic imprints of the intense rainfall in the ITCZ and under TC can now be regularly monitored to better understand the variability of the oceanic part of the global water cycle. We will present how SMOS data, along with concurrent in situ Argo ocean-profile data, other satellite observations of sea

  14. The variations of long time period slow slip events along the Ryukyu subduction zone

    NASA Astrophysics Data System (ADS)

    Tu, Y. T.; Heki, K.

    2014-12-01

    Slow slip events (SSEs) are a type of slow earthquakes that can be observed with Global Positioning System (GPS) networks in the world. Those events are detected on intensely coupled plate boundaries such as Cascadia subduction zone (Dragert et al., 2001), western North America, Mexico (Kostoglodov et al., 2003), Alaska (Ohta et al., 2007) and Tokai and Boso areas (Ozawa et al., 2002, 2003), central Japan and are considered to have relations to large subduction thrust earthquakes. However, in southwestern Ryukyu trench where most of researchers believe that it should be a decoupled plate boundary, SSEs recur regularly and are located at a patch that is as deep as 20 to 40 km (Heki and Kataoka, 2008). For comprehending the characteristics and time variations of SSEs in this area, the GEONET GPS data of 16 years are used in this study. During 1997 to 2014, more than thirty SSEs are identified near Hateruma Island, Ryukyu. The average recurrence interval is calculated to be 6.3 months and release seismic moment is Mw 6.6 on average. However, the values of recurrence interval are not invariable. From 1997 to 2002, interval period of SSEs is 7.5 months, but during 2002 to 2008, the interval period decreases suddenly to 5.5 months. After 2008, the value restores to 7.2 months again. Furthermore, the slip amount of SSEs in this area varies with time. From 1997 to 2002, the slip is 9.5 cm/year; and during 2002 to 2008, the value slightly increases to 10.5 cm/year. However, in 2008 to 2013, the slip drops to 6.6 cm/year, but accord to the trend of cumulative slip, the slip value would increase in 2014. Considering these data, we find the slip values increase conspicuously in 2002 and 2013. Coincidentally, one Mw 7.1 thrust earthquake occurred in 2002 and earthquake swarm activity started in the Okinawa trough approximately 50km north of the SSE patch. In 2013, another earthquake swarm activity occurred in nearly the same area as the 2002 activity. This suggests that the

  15. EQAS for peripheral blood morphology in Spain: a 6-year experience.

    PubMed

    Gutiérrez, G; Merino, A; Domingo, A; Jou, J M; Reverter, J C

    2008-12-01

    The Spanish haematology external quality assessment scheme (EQAS), established in 1984, is run by the Spanish Haematology and Haemotherapy Association (AEHH) [Quality Assurance in Health Care 3 (1991) 75] and functions to evaluate the quality and reproducibility of the assessment of diagnostic samples by clinical laboratories. The Hospital Clinic of the University of Barcelona (HCB) serves as the EQAS Coordination Centre and follows the guidelines established by the International Committee for Standardization in Haematology [Annali dell'Istituto superiore di Sanità 31 (1995) 95; International Journal of Hematology 68 (1998) 45]. During the period 2001-2006, replicates of 25 different blood films were sent to 604 EQAS participants for cell morphology evaluation. Some patient details corresponding to the samples were disclosed, such us age, sex, haemoglobin value and white blood cell count. The participants were asked to select up to four significant morphology features using a coding list, provided by the Coordination Centre, which included significant morphological alterations that appear in haematopoietic cells. For each survey, individual results were assessed against the morphological reference results (MRR) established by the Cytology Group of the AEHH ('true' answers). This paper describes the organization of the 6-year-long study and the evaluation of laboratory performance for blood smear interpretation by the Spanish haematology EQAS. Different performance levels were detected relative to the laboratory category. Laboratories providing services to hospitalized patients showed higher performances compared with laboratories providing services to nonhospitalized patients. Pathological lymphoid cells were the most difficult to identify by the participants. To improve the results in EQAS peripheral blood morphology, the development of specific cytology educational trainings is discussed. PMID:18983297

  16. Estimating return periods of extreme values from relatively short time series of winds

    NASA Astrophysics Data System (ADS)

    Jonasson, Kristjan; Agustsson, Halfdan; Rognvaldsson, Olafur; Arfeuille, Gilles

    2013-04-01

    An important factor for determining the prospect of individual wind farm sites is the frequency of extreme winds at hub height. Here, extreme winds are defined as the value of the highest 10 minutes averaged wind speed with a 50 year return period, i.e. annual exceeding probability of 2% (Rodrigo, 2010). A frequently applied method to estimate winds in the lowest few hundred meters above ground is to extrapolate observed 10-meter winds logarithmically to higher altitudes. Recent study by Drechsel et al. (2012) showed however that this methodology is not as accurate as interpolating simulated results from the global ECMWF numerical weather prediction (NWP) model to the desired height. Observations of persistent low level jets near Colima in SW-Mexico also show that the logarithmic approach can give highly inaccurate results for some regions (Arfeuille et al., 2012). To address these shortcomings of limited, and/or poorly representative, observations and extrapolations of winds one can use NWP models to dynamically scale down relatively coarse resolution atmospheric analysis. In the case of limited computing resources one has typically to make a compromise between spatial resolution and the duration of the simulated period, both of which can limit the quality of the wind farm siting. A common method to estimate maximum winds is to fit an extreme value distribution (e.g. Gumbel, gev or Pareto) to the maximum values of each year of available data, or the tail of these values. If data are only available for a short period, e.g. 10 or 15 years, then this will give a rather inaccurate estimate. It is possible to deal with this problem by utilizing monthly or weekly maxima, but this introduces new problems: seasonal variation, autocorrelation of neighboring values, and increased discrepancy between data and fitted distribution. We introduce a new method to estimate return periods of extreme values of winds at hub height from relatively short time series of winds, simulated

  17. Pure Point Spectrum of the Floquet Hamiltonian for the Quantum Harmonic Oscillator Under Time Quasi-Periodic Perturbations

    NASA Astrophysics Data System (ADS)

    Wang, W.-M.

    2008-01-01

    We prove that the 1- d quantum harmonic oscillator is stable under spatially localized, time quasi-periodic perturbations on a set of Diophantine frequencies of positive measure. This proves a conjecture raised by Enss-Veselic in their 1983 paper [EV] in the general quasi-periodic setting. The motivation of the present paper also comes from construction of quasi-periodic solutions for the corresponding nonlinear equation.

  18. Generational and Time Period Differences in American Adolescents’ Religious Orientation, 1966–2014

    PubMed Central

    Twenge, Jean M.; Exline, Julie J.; Grubbs, Joshua B.; Sastry, Ramya; Campbell, W. Keith

    2015-01-01

    In four large, nationally representative surveys (N = 11.2 million), American adolescents and emerging adults in the 2010s (Millennials) were significantly less religious than previous generations (Boomers, Generation X) at the same age. The data are from the Monitoring the Future studies of 12th graders (1976–2013), 8th and 10th graders (1991–2013), and the American Freshman survey of entering college students (1966–2014). Although the majority of adolescents and emerging adults are still religiously involved, twice as many 12th graders and college students, and 20%–40% more 8th and 10th graders, never attend religious services. Twice as many 12th graders and entering college students in the 2010s (vs. the 1960s–70s) give their religious affiliation as “none,” as do 40%–50% more 8th and 10th graders. Recent birth cohorts report less approval of religious organizations, are less likely to say that religion is important in their lives, report being less spiritual, and spend less time praying or meditating. Thus, declines in religious orientation reach beyond affiliation to religious participation and religiosity, suggesting a movement toward secularism among a growing minority. The declines are larger among girls, Whites, lower-SES individuals, and in the Northeastern U.S., very small among Blacks, and non-existent among political conservatives. Religious affiliation is lower in years with more income inequality, higher median family income, higher materialism, more positive self-views, and lower social support. Overall, these results suggest that the lower religious orientation of Millennials is due to time period or generation, and not to age. PMID:25962174

  19. Generational and time period differences in American adolescents' religious orientation, 1966-2014.

    PubMed

    Twenge, Jean M; Exline, Julie J; Grubbs, Joshua B; Sastry, Ramya; Campbell, W Keith

    2015-01-01

    In four large, nationally representative surveys (N = 11.2 million), American adolescents and emerging adults in the 2010s (Millennials) were significantly less religious than previous generations (Boomers, Generation X) at the same age. The data are from the Monitoring the Future studies of 12th graders (1976-2013), 8th and 10th graders (1991-2013), and the American Freshman survey of entering college students (1966-2014). Although the majority of adolescents and emerging adults are still religiously involved, twice as many 12th graders and college students, and 20%-40% more 8th and 10th graders, never attend religious services. Twice as many 12th graders and entering college students in the 2010s (vs. the 1960s-70s) give their religious affiliation as "none," as do 40%-50% more 8th and 10th graders. Recent birth cohorts report less approval of religious organizations, are less likely to say that religion is important in their lives, report being less spiritual, and spend less time praying or meditating. Thus, declines in religious orientation reach beyond affiliation to religious participation and religiosity, suggesting a movement toward secularism among a growing minority. The declines are larger among girls, Whites, lower-SES individuals, and in the Northeastern U.S., very small among Blacks, and non-existent among political conservatives. Religious affiliation is lower in years with more income inequality, higher median family income, higher materialism, more positive self-views, and lower social support. Overall, these results suggest that the lower religious orientation of Millennials is due to time period or generation, and not to age. PMID:25962174

  20. Global upper mantle structure from long-period differential travel times

    SciTech Connect

    Woodward, R.L.; Masters, G. )

    1991-04-10

    The authors have made over ten thousand measurements of PP-P and SS-S differential travel times from long-period Global Digital Seismograph Network recordings of all events with m{sub b} {ge} 5.5 which occurred during the years 1976 and 1986. The experiments indicate that lower-mantle structure and source-receiver structure can each contribute approximately {plus minus}0.5 s to the measured PP-P residuals so there is considerable signal to be explained. The pattern observed in the PP-P measurements is similar to the pattern observed in the SS-S measurements, with the SS-S residuals 2 to 4 times larger in magnitude. Comparisons of measured residuals to those predicted by the upper-mantle models of Woodhouse and Dziewonski show that the overall patterns are quite similar but the amplitude of the model residuals is roughly a factor of 2 too small. Comparisons with the predictions of a whole-mantle model of Tanimoto again shows that the predicted pattern of residuals is reasonably consistent with the observations but now the predicted residuals are too large by about a factor of 2. They have also binned the measurements according to the tectonic regionalization GTR1 of Jordan and find a qualitative correlation of average residual with tectonic region. In particular, Precambrian shields show a strong anomaly, and there is a correlation of residual size with the age of oceanic crust at the bounce point. For all tectonic regions the ratio of SS-S to PP-P residuals is approximately 2. This ratio is consistent with a thermal origin for the observed signal. Finally, measurements show no compelling evidence for azimuthal anisotroph which might be related to fossil spreading direction or the direction of absolute plate motion.

  1. Cardiac systolic time intervals in fetal monkeys: pre-ejection period.

    PubMed

    Murata, Y; Martin, C B; Ikenoue, T; Petrie, R H

    1978-10-01

    The systolic time intervals of the fetal cardiac cycle were studied by means of simultaneous recordings of electrocardiogram (ECG) and ultrasound Doppler cardiogram (DCG) in chronic preparations of fetal rhesus monkeys. Recordings were made under physiologic conditions as well as during various experimental stresses. The pre-ejection period (PEP) showed no significant relationship with heart rate in the unstressed fetuses, but the acceleration of heart rate induced by epinephrine was accompanied by shortening of PEP. The PEP increased with advancing fetal age. The PEP was inversely correlated with left ventricular end-diastolic pressure and arterial pulse pressure, but showed a positive correlation with both systolic and diastolic arterial blood pressure. The PEP also exhibited strong negative correlation with arterial blood pH. the prolongation was essentially the same whether acidosis was of respiratory or metabolic origin. The PEP increased slightly but significantly during nonacidemic hypoxemia; however, there was no correlation between Pao2 and PEP Epinephrine shortened the PEP significantly, whereas the effect of atropine was inconsistent. Alteration of the plasma glucose level by injection of insulin or glucose did not affect PEP. These findings demonstrate that the PEP may be a useful indicator of fetal cardiac performance, reflecting both myocardial contractility and the hemodynamic state of the cardiovascular system. PMID:30282

  2. Dynamics of thin liquid films on surfaces with a time-periodic wettability.

    PubMed

    Suman, Balram; Kumar, Satish

    2006-12-01

    The dynamics of thin liquid films on surfaces whose wettability changes in a time-periodic manner are examined in this work. A nonlinear evolution equation based on the lubrication approximation is used to describe the film height, and attractions due to van der Waals forces are incorporated. Film wettability is varied through an imposed sinusoidal modulation of the Hamaker constant. A linear stability analysis predicts that if the mean Hamaker constant is negative, disturbances at the film surface will eventually decay regardless of the amplitude and frequency of the oscillation. However, numerical solution of the evolution equation shows that the film can rupture at a given frequency if the amplitude is sufficiently large. The associated characteristic wavelength can be predicted from results for constant-wettability surfaces if an appropriate effective Hamaker constant is used. For positive mean Hamaker constants, film rupture can be accelerated, delayed, or prevented depending on how the Hamaker constant changes early in the oscillation cycle. The effects of spatial gradients in wettability are also considered, and it is found that oscillation can delay but not prevent rupture. Inclusion of short-range repulsive forces leads to the formation of droplet-like structures separated by ultra-thin films, but this can be prevented by sufficiently large and slow oscillations of the Hamaker constant. The results of this work may find use in applications that make use of surfaces whose wettability can be controlled by external stimuli. PMID:17011570

  3. Mars exploration, Venus swingby and conjunction class mission modes, time period 2000 to 2045

    NASA Technical Reports Server (NTRS)

    Young, A. C.; Mulqueen, J. A.; Skinner, J. E.

    1984-01-01

    Trajectory and mission requirement data are presented for Earth-Mars opposition class and conjunction class round trip stopover mission opportunities available during the time period year 2000 to year 2045. The opposition class mission employs the gravitational field of Venus to accelerate the space vehicle on either the outbound or inbound leg. The gravitational field of Venus was used to reduce the propulsion requirement associated with the opposition class mission. Representative space vehicle systems are sized to compare the initial mass required in low Earth orbit of one mission opportunity with another mission opportunity. The interplanetary space vehicle is made up of the spacecraft and the space vehicle acceleration system. The space vehicle acceleration system consists of three propulsion stages. The first propulsion stage performs the Earth escape maneuver; the second stage brakes the spacecraft and Earth braking stage into the Mars elliptical orbit and effects the escape maneuver from the Mars elliptical orbit. The third propulsion stage brakes the mission module into an elliptical orbit at Earth return. The interplanetary space vehicle was assumed to be assembled in and depart from the space station circular orbit.

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

    SciTech Connect

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

    1987-06-19

    The development of mass spectrometric techniques for determination of STTh abundance has made it possible to reduce analytical errors in STYU-STUU-STTh dating of corals even with very small samples. Samples of 6 x 10Y atoms of STTh can be measured to an accuracy of +/- 3% (2sigma) and 3 x 10 atoms of STTh can be measured to an accuracy of +/- 0.2%. The time range over which useful age data on corals can be obtained now ranges from about 50 to about 500,000 years. For young corals, this approach may be preferable to UC dating. The precision should make it possible to critically test the Milankovitch hypothesis concerning Pleistocene climate fluctuations. Analyses of a number of corals that grew during the last interglacial period yield ages of 122,000 to 130,000 years. The ages coincide with, or slightly postdate, the summer solar insolation high at 65N latitude which occurred 128,000 years ago. This supports the idea that changes in Pleistocene climate can be the result of variations in the distribution of solar insolation caused by changes in the geometry of the earth's orbit and rotation axis.

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

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    The development of mass spectrometric techniques for determination of Th-230 abundance has made it possible to reduce analytical errors in (U-238)-(U-234)-(Th-230) dating of corals even with very small samples. Samples of 6 x 10 to the 8th atoms of Th-230 can be measured to an accuracy of + or - 3 percent (2sigma), and 3 x 10 to the 10th atoms of Th-230 can be measured to an accuracy of + or - 0.2 percent. The time range over which useful age data on corals can be obtained now ranges from about 50 to about 500,000 years. For young corals, this approach may be preferable to C-14 dating. The precision with which the age of a coral can now be determined should make it possible to critically test the Milankovitch hypothesis concerning Pleistocene climate fluctuations. Analyses of a number of corals that grew during the last interglacial period yield ages of 122,000 to 130,000 years. The ages coincide with, or slightly post-date, the summer solar insolation high at 65 deg N latitude which occurred 128,000 years ago. This supports the idea that changes in Pleistocene climate can be the result of variations in the distribution of solar insolation caused by changes in the geometry of the earth's orbit and rotation axis.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  7. Lean body mass change over 6 years is associated with dietary leucine intake in an older Danish population.

    PubMed

    McDonald, Cameron Keith; Ankarfeldt, Mikkel Z; Capra, Sandra; Bauer, Judy; Raymond, Kyle; Heitmann, Berit Lilienthal

    2016-05-01

    Higher protein intake, and particularly higher leucine intake, is associated with attenuated loss of lean body mass (LBM) over time in older individuals. Dietary leucine is thought to be a key mediator of anabolism. This study aimed to assess this relationship over 6 years among younger and older adult Danes. Dietary leucine intake was assessed at baseline and after 6 years in men and women, aged 35-65 years, participating in the Danish cohort of the WHO-MONICA (Multinational MONItoring of trends and determinants in CArdiovascular disease) study (n 368). Changes in LBM over the 6 years were measured by bioelectrical impedance using equations developed for this Danish population. The association between leucine and LBM changes was examined using multivariate linear regression and ANCOVA analyses adjusted for potential confounders. After adjustment for baseline LBM, sex, age, energy intake and physical activity, leucine intake was associated with LBM change in those older than 65 years (n 79), with no effect seen in those younger than 65 years. Older participants in the highest quartile of leucine intake (7·1 g/d) experienced LBM maintenance, whereas lower intakes were associated with LBM loss over 6 years (for trend: β=0·434, P=0·03). Sensitivity analysis indicated no effect modification of sex or the presence of CVD. Greater leucine intake in conjunction with adequate total protein intake was associated with long-term LBM retention in a healthy older Danish population. This study corroborates findings from laboratory investigations in relation to protein and leucine intakes and LBM change. A more diverse and larger sample is needed for confirmation of these results. PMID:26979049

  8. The dancing sky: 6 years of night-sky observations at Cerro Paranal

    NASA Astrophysics Data System (ADS)

    Patat, F.

    2008-04-01

    Aims: This work provides the results of the first six years of operation by the systematic night-sky monitoring at ESO-Paranal (Chile). Methods: The UBVRI night-sky brightness was estimated on about 10 000 VLT-FORS1 archival images, obtained on more than 650 separate nights, distributed over 6 years, and covering the descent from maximum to minimum of sunspot cycle n. 23. Additionally, a set of about 1000 low-resolution, optical, night-sky spectra were extracted and analysed. Results: The unprecedented database discussed in this paper has led to detecting a clear seasonal variation of the broad-band night-sky brightness in the VRI passbands, similar to the well-known semi-annual oscillation of the Na I D doublet. The spectroscopic data demonstrate that this seasonality is common to all spectral features, with the remarkable exception of the OH rotational-vibrational bands. A clear dependency on the solar activity is detected in all passbands and is particularly pronounced in the U band, where the sky brightness decreased by ~0.6 mag arcsec-2 from maximum to minimum of solar cycle n. 23. No correlation is found between solar activity and the intensity of the Na I D doublet and the OH bands. A strong correlation between the intensity of N I 5200 Å and [OI]6300, 6364 Å is reported here for the first time. The paper also addresses the determination of the correlation time-scales with solar activity and the possible connection with the flux of charged particles emitted by the Sun. Based on observations with ESO Telescopes at Paranal Observatory.

  9. Incidence pattern of thyroid cancer in Norway: influence of birth cohort and time period.

    PubMed

    Akslen, L A; Haldorsen, T; Thoresen, S O; Glattre, E

    1993-01-21

    The incidence of thyroid cancer in Norway increased about 2-fold for both sexes during the period 1955 to 1989 (4691 cases). In the last 5-year period, however, a decline was observed, especially among females. The ratio between age-adjusted incidence rates in Northern Norway compared with Southern Norway was 1.6 for females and 1.5 for males, and the incidence pattern during the period was similar in the 2 regions. The analysis of age-cohort-period models showed a strong cohort effect in both sexes. The reason for this is not clear, although radiation treatment during childhood and dietary habits may possibly be involved. A weaker but statistically significant and transient period effect was also present, giving relatively higher incidence rates, especially in the 1970s. Although this result may be consistent with an influence of radioactive fallout in the northern area, more detailed studies are needed. PMID:8425755

  10. Comparative analysis of Clostridium difficile clinical isolates belonging to different genetic lineages and time periods.

    PubMed

    Spigaglia, Patrizia; Mastrantonio, Paola

    2004-11-01

    Recent studies have shown that Clostridium difficile strains with variant toxins and those with resistance to macrolide-lincosamide-streptogramin B (MLSB) are increasingly causing severe disease and outbreaks in hospital settings. Here, the pathogenicity locus (PaLoc), the acquisition of binary toxin, and the genotypic and phenotypic characteristics of antibiotic resistance of 74 C. difficile clinical strains isolated from symptomatic patients in Italy during different time periods were studied. These strains were found to belong to two different lineages, and those isolated before 1991 were genetically unrelated to the more recent strains. The majority of recent C. difficile strains showed variations in toxin genes and in the toxin negative regulator (tcdC) and had the binary toxin. In 62 % of them, variations in tcdC and the presence of the binary toxin were associated. Five classes of susceptibility/resistance pattern (EC-a to -e) for erythromycin and clindamycin were identified in all strains studied. Most of the recent isolates belonged to EC-d and EC-e and, although erythromycin-resistant in vitro, did not harbour the commonly associated ermB determinant. Interestingly, two strains of the EC-d class were resistant to clindamycin only after induction with subinhibitory concentrations of the antibiotic. A decrease in tetracycline and chloramphenicol MIC values was also observed in the recently isolated strains, associated with less frequent detection of the catD and tetM genes. Two tetM-positive strains were resistant in vitro only after induction with subinhibitory concentrations of the antibiotic. The acquisition of the binary toxin, the possible increase in toxin production due to a mutated negative regulator and a decrease in the fitness cost as a result of lower levels of antibiotic resistance or other mechanisms may have led to the successful establishment of these new phenotypes, with potentially serious clinical implications. PMID:15496392

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

    PubMed

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

    2012-05-01

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

  12. Sharp spatiotemporal patterns in the diffusive time-periodic logistic equation

    NASA Astrophysics Data System (ADS)

    Du, Yihong; Peng, Rui

    To reveal the complex influence of heterogeneous environment on population systems, we examine the asymptotic profile (as ɛ→0) of the positive solution to the perturbed periodic logistic equation {

  13. An Analysis of Bone Donor Deferral Rates in Scotland - a 6-Year Study.

    PubMed

    Galea, George

    2011-12-01

    BACKGROUND: The Scottish National Blood Transfusion Service (SNBTS) is the main provider of tissues in Scotland. Tissue collection programmes were established in the mid-1990s, and the range of tissues collected has increased progressively over the years. MATHODS: Whilst the majority of tissues are obtained from cadaveric donations, bone is collected only from living donors who are usually patients undergoing primary hip replacement surgery (surgical donors). The bone is collected in an operating theatre, and, once stored, no further processing takes place prior to issue. Bone that fails for any reason (quality, microbiology or virological nonnegative result) is discarded. RESULTS: The deferral rate amongst live surgical bone donors in Scotland is around 65%, and it has been slowly and progressively rising from around 55% over the past few years. This needed investigated, particularly because comparisons with blood donors show that the deferral rate amongst bone donors is more than double that of first-time blood donors (29.7%). Our processes and systems are standardised, and our cohort of bone bank nurses have all been similarly trained and competency assessed. Moreover our data collection was done in a uniform fashion. It was therefore possible to conduct a 6-year audit on bone donor deferrals. It was found that a history of transfusion (16%), history of malignancy (18%) and bone quality (26%) were the main reasons for bone donor deferrals, accounting for 60% of all deferrals. CONCLUSIONS: When these are taken into account, the residual deferral rates become very similar numerically to blood donors. It is important to note however that there are significant differences between the blood and bone donor cohorts. This study also highlighted some of deferral reasons. Particularly malignancy is a cause of significant numbers of deferrals, and the evidence of transmissibility of malignancy through bone donation is not strong. More robust risk assessments should be

  14. A 6-year follow-up study of adult patients with congenitally corrected transposition.

    PubMed

    Koželj, Mirta; Cvijić, Marta; Berden, Pavel; Podnar, Tomaž

    2015-10-01

    The aims of this study were to assess the development of heart failure in patients with congenitally corrected transposition of the great arteries in a medium-term follow-up, to identify the impact of tricuspid regurgitation on the development of heart failure, and to determine the most reliable marker for its identification. The prospective 6-year follow-up study included 19 adult patients. All patients were evaluated clinically by the determination of N-terminal pro-hormone brain natriuretic peptide levels, exercise stress testing, echocardiography magnetic resonance, or CT. Among them, two patients died of heart failure. There was a decline in exercise capacity and systolic systemic ventricular function (p=0.011). Systemic ventricular ejection fraction decreased (48.3±13.7 versus 42.7±12.7%, p=0.001). Tissue Doppler imaging showed a decline in peak tricuspid systolic annular velocity (10.3±2.0 versus 8.3±2.5 cm/second, p=0.032) and peak tricuspid early diastolic annular velocity (14.6±4.3 versus 12.0±4.5 cm/second, p=0.048). The tricuspid regurgitation did not increase significantly. N-terminal pro-hormone brain natriuretic peptide levels increased (127.0 ng/L(82.3-305.8) versus 226.0 ng/L(112.5-753.0), p=0.022). Progressive exercise intolerance in congenitally corrected transposition of the great arteries appears to be driven mainly by a progression in systemic right ventricular dysfunction. Tricuspid regurgitation is likely to play a role, especially in patients with structural abnormalities of the tricuspid valve - Ebstein anomaly. The N-terminal pro-hormone brain natriuretic peptide levels and tissue Doppler parameters appear sensitive in detecting changes over time and may guide management. PMID:25522750

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

    SciTech Connect

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

    2014-06-10

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

  16. Pre-exercise glucose ingestion at different time periods and blood glucose concentration during exercise.

    PubMed

    Tokmakidis, S P; Volaklis, K A

    2000-08-01

    The purpose of this study was to investigate the effects of glucose ingestion (GI) at different time periods prior to exercise on blood glucose (BG) levels during prolonged treadmill running. Eight subjects (X+/-SD), age 20+/-0.5yr, bodymass 70.7+/-4.1 kg, height 177+/-4 cm, VO2max 52.8+/-7.8 ml x kg(-1) x min(-1) who underwent different experimental conditions ingested a glucose solution (1 g/kg at 350 ml) 30 min (gl-30), 60 min (gl-60), 90 min (gl-90), and a placebo one 60 min (pl-60) prior to exercise in a counterbalanced design. Afterwards they ran at 65% of VO2max for 1 hour and then at 75 % of VO2max till exhaustion. Fingertip blood samples (10 microl) were drawn every 15 min before and during exercise for the determination of BG levels. Oxygen uptake (VO2), heart rate (HR), and blood lactate (La) were also measured every 15 min during exercise. Peak BG values were reached within 30 min after GI but were different (p < 0.01) at the onset of exercise (gl-30: 147+/-22, gl-60: 118+/-25, gl-90: 109+/-22, pl-60: 79+/-5mg/dl). The two-way ANOVA repeated measures and the Tukey post-hoc test revealed a higher BG concentration (p < 0.05) for the gl-30 and the pl-60 as compared to the gl-60 and gl-90 during running (e.g. 15min run: 82+/-11, 68+/-5, 64+/-3, 78+/-7, and 60min run: 98+/-12, 85+/-12, 83+/-11, 94+/-11 mg/dl for gl-30, gl-60, gl-90, and pl-60, respectively). However, this did not significantly affect the duration of treadmill running. The La levels were higher (p < 0.05) after GI as compared to placebo throughout exercise (values at exhaustion: 4.6+/-0.2, 5.0+/-1.5, 4.8+/- 1.7 mmol/l for gl-30, gl-60, gl-90, and 3.5+/-0.8 mmol/l for placebo). The gl-30 and the placebo fluctuated closer to normoglycaemic levels. The glucose ingestion (60 to 90 min) prior to exercise lowered the blood glucose levels without affecting the duration of running performance at 75% VO2max. Thus, in order to maintain normoglycaemic levels, pre-exercise glucose supplementation should

  17. The CryoSat Interferometer after 6 years in orbit: calibration and achievable performance

    NASA Astrophysics Data System (ADS)

    Scagliola, Michele; Fornari, Marco; De Bartolomei, Maurizio; Bouffard, Jerome; Parrinello, Tommaso

    2016-04-01

    The main payload of CryoSat is a Ku-band pulse width limited radar altimeter, called SIRAL (Synthetic interferometric radar altimeter). When commanded in SARIn (synthetic aperture radar interferometry) mode, through coherent along-track processing of the returns received from two antennas, the interferometric phase related to the first arrival of the echo is used to retrieve the angle of arrival of the scattering in the across-track direction. In fact, the across-track echo direction can be derived by exploiting the precise knowledge of the baseline vector (i.e. the vector between the two antennas centers of phase) and simple geometry. The end-to-end calibration strategy for the CryoSat interferometer consists on in-orbit calibration campaigns following the approach described in [1]. From the beginning of the CryoSat mission, about once a year the interferometer calibration campaigns have been periodically performed by rolling left and right the spacecraft of about ±0.4 deg. This abstract is aimed at presenting our analysis of the calibration parameters and of the achievable performance of the CryoSat interferometer over the 6 years of mission. Additionally, some further studies have been performed to assess the accuracy of the roll angle computed on ground as function of the aberration (the apparent displacement of a celestial object from its true position, caused by the relative motion of the observer and the object) correction applied to the attitude quaternions, provided by the Star Tracker mounted on-board. In fact, being the roll information crucial to obtain an accurate estimate of the angle of arrival, the data from interferometer calibration campaigns have been used to verify how the application of the aberration correction affects the roll information and, in turns, the measured angle of arrival. [1] Galin, N.; Wingham, D.J.; Cullen, R.; Fornari, M.; Smith, W.H.F.; Abdalla, S., "Calibration of the CryoSat-2 Interferometer and Measurement of Across

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

    PubMed

    Panchelyuga, V A; Panchelyuga, M S

    2015-01-01

    Results of local fractal analysis of 329-per-day time series of 239Pu alpha-decay rate fluctuations by means of all permutations method (APM) are presented. The APM-analysis reveals in the time series some steady frequency set. The coincidence of the frequency set with the Earth natural oscillations was demonstrated. A short review of works by different authors who analyzed the time series of fluctuations in processes of different nature is given. We have shown that the periods observed in those works correspond to the periods revealed in our study. It points to a common mechanism of the phenomenon observed. PMID:26016038

  19. Changes in the American Interventional Radiology Literature: Comparison over a 10-Year Time Period

    SciTech Connect

    Ray, Charles E. Gupta, Rajan; Blackwell, John

    2006-08-15

    Purpose. To determine the changes that occurred regarding interventional radiologic research in the major American radiology journals between 1992-1993 and 2002-2003. Methods. Articles published in three major American radiology journals (Journal of Vascular and Interventional Radiology, American Journal of Roentgenology, and Radiology) during two distinct 24-month time periods (1992-1993 and 2002-2003) were evaluated. All articles judged to be pertinent to the interventional radiologic community were included. Investigations included in journal subheadings other than 'interventional' or 'vascular radiology' were included if the emphasis of the article was on a vascular imaging modality or peripheral intervention. Exclusions included: case reports, technical reports, letters to the editor, breast interventions, and primary neurointerventions. Data were collected regarding the affiliations of the primary author (nationality, hospital type, department); primary category of interest of the investigation; funding information; and study design variables. Two-by-two chi-squared statistical analyses were performed comparing the variables from the early and late data sets. Results. A total of 405 articles met the inclusion criteria for the early data set (1992-1993); 488 articles met the inclusion criteria for the late data set (2002-2003). Variables that demonstrated a statistically significant decrease from the early data set to the late data set included: articles in which the primary author was from a department of radiology (91.1% vs. 86.3%; p < 0.025); articles written by a primary author who was American (69.4% vs. 44.6%; p < 0.001); and articles with a primary category of investigation that had a nonvascular intervention focus (22.7% vs. 11.9%; p < 0.001). Variables that demonstrated a statistically significant increase from the early data set to the late data set included primary authors from Western Europe (18.0% vs. 30.1%; p < 0.001) and Asia (6.6% vs. 18.4%; p

  20. The Preschool Attention-Deficit/Hyperactivity Disorder Treatment Study (PATS) 6-Year Follow-Up

    ERIC Educational Resources Information Center

    Riddle, Mark A.; Yershova, Kseniya; Lazzaretto, Deborah; Paykina, Natalya; Yenokyan, Gayane; Greenhill, Laurence; Abikoff, Howard; Vitiello, Benedetto; Wigal, Tim; McCracken, James T.; Kollins, Scott H.; Murray, Desiree W.; Wigal, Sharon; Kastelic, Elizabeth; McGough, James J.; dosReis, Susan; Bauzo-Rosario, Audrey; Stehli, Annamarie; Posner, Kelly

    2013-01-01

    Objective: To describe the clinical course of attention-deficit/hyperactivity disorder (ADHD) symptom severity and diagnosis from ages 3 to 5 up to 9 to 12 years during a 6-year follow-up after the original Preschool ADHD Treatment Study (PATS). Method: A total of 207 participants (75% male) from the original PATS, assessed at baseline (mean age,…

  1. Pyramid Educational Method for 3 to 6-Year-Old Children: Theory and Research.

    ERIC Educational Resources Information Center

    van Kuyk, Jef J.

    This study evaluated the effectiveness of the Pyramid method, an educational method for 3- to 6-year-olds. The Pyramid method seeks to improve young children's chances for a successful primary school career, particularly among ethnic minorities (of Turkish, Moroccan, Cape Verdian, and Surinam origins) and Dutch children of poorly educated parents.…

  2. Tetralogy of Fallot in a 6-year-old albino ferret (Mustela putorius furo)

    PubMed Central

    Laniesse, Delphine; Hébert, Julie; Larrat, Sylvain; Hélie, Pierre; Pouleur-Larrat, Bénédicte; Belanger, Marie C.

    2014-01-01

    Tetralogy of Fallot associated with bidirectional shunting across a large ventricular septal defect, was found in a 6-year-old ferret. The prognosis associated with tetralogy of Fallot is usually poor. This case is interesting given the advanced age of the ferret. The bidirectional shunting, responsible for an acyanotic disease, may explain the unexpected prolonged survival in this ferret. PMID:24790231

  3. Voucher Users and Revitalized Public-Housing Residents 6 Years after Displacement

    ERIC Educational Resources Information Center

    Brooks, Fred; Lewinson, Terri; Aszman, Jennifer; Wolk, Jim

    2012-01-01

    Objective: A total of 6 years after displacement by a Housing Opportunities for People Everywhere (HOPE VI) project, this research examines residents who returned to the redeveloped community and residents who decided to keep their vouchers and were living in private sector housing. Respondents were compared on the following variables: application…

  4. Basic Facts about Low-Income Children: Children under 6 Years, 2013. Fact Sheet

    ERIC Educational Resources Information Center

    Jiang, Yang; Ekono, Mercedes; Skinner, Curtis

    2015-01-01

    Children under 18 years represent 23 percent of the population, but they comprise 33 percent of all people in poverty. Among all children, 44 percent live in low-income families and approximately one in every five (22 percent) live in poor families. Young children under age 6 years appear to be particularly vulnerable, with 48 percent living in…

  5. Intonation Facilitates Contrast Resolution: Evidence from Japanese Adults and 6-Year Olds

    ERIC Educational Resources Information Center

    Ito, Kiwako; Jincho, Nobuyuki; Minai, Utako; Yamane, Naoto; Mazuka, Reiko

    2012-01-01

    Two eye-tracking experiments tested how pitch prominence on a prenominal adjective affects contrast resolution in Japanese adult and 6-year old listeners. Participants located two animals in succession on displays with multiple colored animals. In Experiment 1, adults' fixations to the contrastive target (pink cat [right arrow] GREEN cat) were…

  6. Soil-profile distribution of inorganic N during 6 years of integrated crop-livestock management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excessive accumulation of soil nitrate-N can threaten water and air quality. How integrated crop-livestock systems might influence soil-profile nitrate-N accumulation has not been investigated. Therefore, we determined soil nitrate-N accumulation during 6 years of evaluation of diverse cropping sy...

  7. Phonological Awareness Abilities of 6-Year-Old Children with Mild to Moderate Phonological Impairments

    ERIC Educational Resources Information Center

    Gernand, Keri Leigh; Moran, Michael J.

    2007-01-01

    Standardized and nonstandardized assessments of phonological awareness skills were administered to two groups of 6-year-old children. Group 1 passed a language screening but exhibited mild or moderate phonological impairments on the "Assessment of Phonological Processes--Revised." Group 2 passed a language screening and exhibited no phonological…

  8. The Microgenetic Emergence of Cooperative Play in 6-Year-Olds Developmentally At-Risk

    ERIC Educational Resources Information Center

    van der Aalsvoort, Geerdina M.; van der Leeden, Rien

    2009-01-01

    Cooperative play was investigated by a controlled pre/post-test intervention design with 28 dyads of 6-year-old students developmentally at-risk. Selection was based upon cut-off scores on a language development test and a nonverbal IQ test, and same-sex pairs were matched within classrooms. Co-variables were: socio economic status, free play time…

  9. A Learning Trajectory in 6-Year-Olds' Thinking about Generalizing Functional Relationships

    ERIC Educational Resources Information Center

    Blanton, Maria; Brizuela, Bárbara M.; Gardiner, Angela Murphy; Sawrey, Katie; Newman-Owens, Ashley

    2015-01-01

    The study of functions is a critical route into teaching and learning algebra in the elementary grades, yet important questions remain regarding the nature of young children's understanding of functions. This article reports an empirically developed learning trajectory in first-grade children's (6-year-olds') thinking about generalizing functional…

  10. Taxometric Analyses of Specific Language Impairment in 6-Year-Old Children

    ERIC Educational Resources Information Center

    Dollaghan, Christine A.

    2011-01-01

    Purpose: To determine whether language scores at age 6 years suggest that specific language impairments (SLIs) distribute in a categorical or in a dimensional fashion. Method: A taxometric analysis of language scores from 601 six-year-old children who were free of neonatal risk factors was performed. From among 4 candidate indicators of SLI, 2…

  11. Multiple Intelligences of 6-Year-Old Children Attending Preschool in Turkey

    ERIC Educational Resources Information Center

    Uysal, Ebru; Akyol, Aysel Koksal

    2007-01-01

    This study was designed to examine 6-year-old pupils attending different preschool institutions in Turkey in view of the multiple-intelligences theory. This research aims at determining whether the gender of pupils attending different preschool institutions leads to differences in their verbal-linguistics, mathematical-logical, visual-spatial,…

  12. Eating Problems at Age 6 Years in a Whole Population Sample of Extremely Preterm Children

    ERIC Educational Resources Information Center

    Samara, Muthanna; Johnson, Samantha; Lamberts, Koen; Marlow, Neil; Wolke, Dieter

    2010-01-01

    Aim: The aim of this study was to investigate the prevalence of eating problems and their association with neurological and behavioural disabilities and growth among children born extremely preterm (EPC) at age 6 years. Method: A standard questionnaire about eating was completed by parents of 223 children (125 males [56.1%], 98 females [43.9%])…

  13. Instabilities of time-periodic, incompressible, inviscid flow in ellipsoidal domains.

    NASA Astrophysics Data System (ADS)

    Biello, Joseph A.; Saldanha, Kenneth I.; Lebovitz, Norman R.

    1999-11-01

    We consider the linear stability of exact, temporally periodic solutions of the Euler equations of incompressible, inviscid flow in an ellipsoidal domain. The problem of linear stability is reduced, without approximation, to a hierarchy of finite-dimensional Floquet problems governing fluid-dynamical perturbations of differing spatial scales and symmetries. We study two of these Floquet problems in detail, emphasizing parameter regimes of special physical significance. One of these regimes includes periodic flows differing only slightly from steady flows. Another includes long-period flows representing the nonlinear outcome of an instability of steady flows. In both cases much of the parameter space corresponds to instability, excepting a region adjacent to the spherical configuration. In the second case, even if the ellipsoid departs only moderately from a sphere, there are filamentary regions of instability in the parameter space. We relate this and other features of our results to properties of reversible and Hamiltonian systems, and compare our results with related studies of periodic flows.

  14. Instabilities of exact, time-periodic solutions of the incompressible Euler equations

    NASA Astrophysics Data System (ADS)

    Biello, Joseph A.; Saldanha, Kenneth I.; Lebovitz, Norman R.

    2000-02-01

    We consider the linear stability of exact, temporally periodic solutions of the Euler equations of incompressible, inviscid flow in an ellipsoidal domain. The problem of linear stability is reduced, without approximation, to a hierarchy of finite-dimensional Floquet problems governing fluid-dynamical perturbations of differing spatial scales and symmetries. We study two of these Floquet problems in detail, emphasizing parameter regimes of special physical significance. One of these regimes includes periodic flows differing only slightly from steady flows. Another includes long-period flows representing the nonlinear outcome of an instability of steady flows. In both cases much of the parameter space corresponds to instability, excepting a region adjacent to the spherical configuration. In the second case, even if the ellipsoid departs only moderately from a sphere, there are filamentary regions of instability in the parameter space. We relate this and other features of our results to properties of reversible and Hamiltonian systems, and compare our results with related studies of periodic flows.

  15. NHEXAS PHASE I REGION 5 STUDY--TIME-ACTIVITY DIARY QUESTIONNAIRE DATA (MONITORING PERIOD 1)

    EPA Science Inventory

    This data set includes responses for 249 time-activity diary questionnaires. The Time Diary and Activity Questionnaire was used for collecting data on detailed (daily) time and location information and activity patterns (for relatively frequent activities when recalling events ov...

  16. Fourth-grade Children’s Dietary Recall Accuracy is Influenced by Retention Interval (Target Period and Interview Time)

    PubMed Central

    Hardin, James W.; Guinn, Caroline H.; Royer, Julie A.; Mackelprang, Alyssa J.; Smith, Albert F.

    2009-01-01

    Background For a 24-hour dietary recall, two possible target periods are the prior 24 hours (24 hours immediately preceding the interview time) and previous day (midnight to midnight of the day before the interview), and three possible interview times are morning, afternoon, and evening. Target period and interview time determine the retention interval (elapsed time between to-be-reported meals and the interview), which, along with intervening meals, can influence reporting accuracy. Objective The effects of target period and interview time on children’s accuracy for reporting school meals during 24-hour dietary recalls were investigated. Design and subjects/setting During the 2004–05, 2005–06, and 2006–07 school years in (city), (state), each of 374 randomly selected fourth-grade children (96% Black) was observed eating two consecutive school meals (breakfast, lunch) and interviewed to obtain a 24-hour dietary recall using one of six conditions defined by crossing two target periods with three interview times. Each condition had 62 or 64 children (half boys). Main outcome measures Accuracy for reporting school meals was quantified by calculating rates for omissions (food items observed eaten but unreported) and intrusions (food items reported eaten but unobserved); a measure of total inaccuracy combined errors for reporting food items and amounts. Statistical analyses performed For each accuracy measure, analysis of variance was conducted with target period, interview time, their interaction, sex, interviewer, and school year in the model. Results There was a target-period effect and a target-period by interview-time interaction on omission rates, intrusion rates, and total inaccuracy (six P values <0.004). For prior-24-hour recalls compared to previous-day recalls, and for prior-24-hour recalls in the afternoon and evening compared to previous-day recalls in the afternoon and evening, omission rates were better by one-third, intrusion rates were better by

  17. Diffusive KPP equations with free boundaries in time almost periodic environments: II. Spreading speeds and semi-wave solutions

    NASA Astrophysics Data System (ADS)

    Li, Fang; Liang, Xing; Shen, Wenxian

    2016-08-01

    In this series of papers, we investigate the spreading and vanishing dynamics of time almost periodic diffusive KPP equations with free boundaries. Such equations are used to characterize the spreading of a new species in time almost periodic environments with free boundaries representing the spreading fronts. In the first part of the series, we showed that a spreading-vanishing dichotomy occurs for such free boundary problems (see [16]). In this second part of the series, we investigate the spreading speeds of such free boundary problems in the case that the spreading occurs. We first prove the existence of a unique time almost periodic semi-wave solution associated to such a free boundary problem. Using the semi-wave solution, we then prove that the free boundary problem has a unique spreading speed.

  18. [A 6-year-old girl who exhibited residual reading disorder during the course of acute encephalopathy].

    PubMed

    Nagaharu, Sachiko; Inaba, Yuji; Motobayashi, Mitsuo; Misawa, Yuka; Fukuyama, Tetsuhiro; Higuchi, Tsukasa; Harada, Machiko

    2012-11-01

    We assessed a 6-year-old girl who developed status epilepticus and exhibited transient aphasia during the course of acute encephalopathy with late reduced diffusion, and who had a residual reading disorder in the recovery period. The aphasia appeared to be fluent aphasia and anomia, suggesting that the reading disorder during the recovery process was due to impairment of the phonological process. There were no biphasic seizures during the course of the patient's illness, but this case was acute encephalopathy with febrile convulsive status epilepticus (AEFCSE) from the standpoint of the characteristic imaging findings. Lesions in the left parietal and temporal lobes were detected on MRI diffusion-weighted images and by SPECT and MRS, and they appeared to be the lesions responsible for the aphasia and residual reading disorder. This case appears to be important from the standpoint of assessing the pathophysiology and the treatment of coexisting illness observed in acute encephalopathy. PMID:23240531

  19. Predictors of adolescent outcomes among 4-6-year-old children with attention-deficit/hyperactivity disorder.

    PubMed

    Lahey, Benjamin B; Lee, Steve S; Sibley, Margaret H; Applegate, Brooks; Molina, Brooke S G; Pelham, William E

    2016-02-01

    Children who met Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition (DSM-IV) criteria for attention-deficit/hyperactivity disorder (ADHD) with functional impairment in at least one setting at 4-6 years of age were followed prospectively through age 18 years. On average, the 125 children (107 boys) with ADHD at baseline improved over time, but still continued to exhibit more symptoms, functional impairment, and risky behavior through adolescence than demographically matched healthy comparison children. These findings support the predictive validity of the diagnosis of ADHD at younger ages by demonstrating that the symptoms and impairment are enduring. Nonetheless, there were marked variations in developmental outcomes. Among children with ADHD, higher numbers of inattention and hyperactivity-impulsivity symptoms and higher number of concurrent symptoms (oppositional, conduct disorder, anxiety, and depression) measured at baseline each predicted higher future levels of the same dimension of symptoms. In addition, higher baseline levels of inattention, oppositional, conduct disorder, and anxiety symptoms predicted greater future functional impairment. Among children with ADHD, girls and children from families with lower family incomes had relatively poorer outcomes. Although outcomes varied along a continuum, approximately 10% of the children with ADHD at 4-6 years could be classified as functioning in the normative range on multiple measures during 15-18 years. Although this finding awaits replication, lower levels of hyperactivity-impulsivity symptoms at 4-6 years predicted more normative functioning during adolescence. These findings suggest that ADHD identified in early childhood predicts an increased likelihood of functional impairment through adolescence for most, but not all, children. (PsycINFO Database Record PMID:26854503

  20. Resource allocation to kin, friends, and strangers by 3- to 6-year-old children.

    PubMed

    Lu, Hui Jing; Chang, Lei

    2016-10-01

    Kin altruism has been widely observed across species, including humans. However, few studies have discussed the development of kin altruism or its relationship with theory of mind. In this study, 3- to 6-year-old children allocated resources between themselves and kin, a friend, or a stranger in three allocation tasks where the allocation either incurred a cost, incurred no cost, or conferred a disadvantage. The results showed that, compared with 3- and 4-year-olds, 5- and 6-year-olds acted more altruistically toward kin and that kin altruism was uncorrelated with theory of mind. These findings suggest that, within the context of resource allocation, kin altruism emerges toward the end of early childhood and probably differs from other prosocial behavior that relies solely on the understanding of others' perspectives. PMID:27336694

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

    SciTech Connect

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

    2009-08-28

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

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

    PubMed

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

    2016-05-01

    People make systematic errors when they move their unseen dominant hand to a visual target (visuo-haptic matching) or to their other unseen hand (haptic-haptic matching). Why they make such errors is still unknown. A key question in determining the reason is to what extent individual participants' errors are stable over time. To examine this, we developed a method to quantify the consistency. With this method, we studied the stability of systematic matching errors across time intervals of at least a month. Within this time period, individual subjects' matches were as consistent as one could expect on the basis of the variability in the individual participants' performance within each session. Thus individual participants make quite different systematic errors, but in similar circumstances they make the same errors across long periods of time. PMID:27043253

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  5. Detecting unstable periodic orbits in high-dimensional chaotic systems from time series: reconstruction meeting with adaptation.

    PubMed

    Ma, Huanfei; Lin, Wei; Lai, Ying-Cheng

    2013-05-01

    Detecting unstable periodic orbits (UPOs) in chaotic systems based solely on time series is a fundamental but extremely challenging problem in nonlinear dynamics. Previous approaches were applicable but mostly for low-dimensional chaotic systems. We develop a framework, integrating approximation theory of neural networks and adaptive synchronization, to address the problem of time-series-based detection of UPOs in high-dimensional chaotic systems. An example of finding UPOs from the classic Mackey-Glass equation is presented. PMID:23767476

  6. 45 CFR 2526.40 - What is the time period during which an individual may use an education award?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... may use an education award? 2526.40 Section 2526.40 Public Welfare Regulations Relating to Public Welfare (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE ELIGIBILITY FOR AN EDUCATION AWARD § 2526.40 What is the time period during which an individual may use an education award? (a)...

  7. 45 CFR 2526.40 - What is the time period during which an individual may use an education award?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... may use an education award? 2526.40 Section 2526.40 Public Welfare Regulations Relating to Public Welfare (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE ELIGIBILITY FOR AN EDUCATION AWARD § 2526.40 What is the time period during which an individual may use an education award? (a)...

  8. 30 CFR 250.1161 - When may I flare or vent gas for extended periods of time?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 2 2011-07-01 2011-07-01 false When may I flare or vent gas for extended periods of time? 250.1161 Section 250.1161 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION... supported by engineering, geologic, and economic data indicating that the oil and gas produced from the...

  9. 30 CFR 250.1161 - When may I flare or vent gas for extended periods of time?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 2 2014-07-01 2014-07-01 false When may I flare or vent gas for extended periods of time? 250.1161 Section 250.1161 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Production Requirements...

  10. 30 CFR 250.1161 - When may I flare or vent gas for extended periods of time?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 2 2012-07-01 2012-07-01 false When may I flare or vent gas for extended periods of time? 250.1161 Section 250.1161 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Production Requirements...

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

    NASA Astrophysics Data System (ADS)

    Kim, M.; Harman, C. J.

    2013-12-01

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

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

    PubMed

    Wierzcholski, Krzysztof

    2014-01-01

    The present paper is concerned with the calculation of the human hip joint parameters for periodic, stochastic unsteady, motion with asymmetric probability density function for gap height. The asymmetric density function indicates that the stochastic probabilities of gap height decreasing are different in comparison with the probabilities of the gap height increasing. The models of asymmetric density functions are considered on the grounds of experimental observations. Some methods are proposed for calculation of pressure distributions and load carrying capacities for unsteady stochastic conditions in a super thin layer of biological synovial fluid inside the slide biobearing gap limited by a spherical bone acetabulum. Numerical calculations are performed in Mathcad 12 Professional Program, by using the method of finite differences. This method assures stability of numerical solutions of partial differential equations and gives proper values of pressure and load carrying capacity forces occurring in human hip joints. PMID:24707824

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

    PubMed Central

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

    2016-01-01

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

  14. A high-order full-discretization method using Hermite interpolation for periodic time-delayed differential equations

    NASA Astrophysics Data System (ADS)

    Liu, Yilong; Fischer, Achim; Eberhard, Peter; Wu, Baohai

    2015-06-01

    A high-order full-discretization method (FDM) using Hermite interpolation (HFDM) is proposed and implemented for periodic systems with time delay. Both Lagrange interpolation and Hermite interpolation are used to approximate state values and delayed state values in each discretization step. The transition matrix over a single period is determined and used for stability analysis. The proposed method increases the approximation order of the semidiscretization method and the FDM without increasing the computational time. The convergence, precision, and efficiency of the proposed method are investigated using several Mathieu equations and a complex turning model as examples. Comparison shows that the proposed HFDM converges faster and uses less computational time than existing methods.

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

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Bell, P. R.

    1981-01-01

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

  17. Academic Achievement over 8 Years among Children Who Met Modified Criteria for Attention-Deficit/Hyperactivity Disorder at 4-6 Years of Age

    ERIC Educational Resources Information Center

    Massetti, Greta M.; Lahey, Benjamin B.; Pelham, William E.; Loney, Jan; Ehrhardt, Ashley; Lee, Steve S.; Kipp, Heidi

    2008-01-01

    The predictive validity of symptom criteria for different subtypes of ADHD among children who were impaired in at least one setting in early childhood was examined. Academic achievement was assessed seven times over 8 years in 125 children who met symptom criteria for ADHD at 4-6 years of age and in 130 demographically-matched non-referred…

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

    NASA Astrophysics Data System (ADS)

    Wosnitza, Jan Henrik; Sornette, Didier

    2015-04-01

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

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

    PubMed

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

    2016-01-01

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

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

    PubMed Central

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

    2016-01-01

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

  1. Indirect monitoring and analysis of truncal stress over extended time periods.

    PubMed

    Bryant, T N; Fernandes, A; Baty, D

    1986-04-01

    Low back pain is a common ailment encountered in clinical practice, yet there has hitherto been no completely satisfactory method for the measurement of truncal stress, which is a major factor in low back pain. Truncal stress has been difficult to record during the course of a working day because subjects were constrained by trailing cables attached to the monitoring equipment. We have used a pressure sensitive transmitter (radio pill) to record intra-abdominal pressure, which has been shown previously to be an indirect measure of truncal stress. The system makes possible multichannel recordings on magnetic tape throughout the working day by using a portable, battery powered recorder strapped to the subject's waist. A novel ferrite rod contributes materially to minimizing artefacts due to signal loss. The recorded data are replayed, at 60 times real time, into a microcomputer programmed to analyse this data. PMID:2940418

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

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

  3. Are Articular Cartilage Lesions and Meniscus Tears Predictive of IKDC, KOOS, and Marx Activity Level Outcomes after ACL Reconstruction? A 6-Year Multicenter Cohort Study

    PubMed Central

    Cox, Charles L.; Huston, Laura J.; Dunn, Warren R.; Reinke, Emily K.; Nwosu, Samuel K.; Parker, Richard D.; Wright, Rick W.; Kaeding, Christopher C.; Marx, Robert G.; Amendola, Annunziata; McCarty, Eric C.; Wolf, Brian R.; Harrell, Frank E.; Spindler, Kurt P.

    2014-01-01

    Background Identifying risk factors for inferior outcomes after ACL reconstruction (ACLR) is important for prognosis and future treatment. The goal of this study was to determine whether articular cartilage and meniscal variables are predictive of 3 validated sports outcome instruments after ACLR. Hypothesis/Purpose We hypothesized that articular cartilage lesions and meniscus tears/treatment would be predictors of the IKDC, KOOS (all 5 subscales), and Marx activity level at 6 years following ACLR. Study Design Prospective cohort, Level 1 Methods Between 2002 and 2004, 1512 ACLR subjects were prospectively enrolled and followed longitudinally with the IKDC, KOOS, and Marx activity score completed at entry, 2, and 6 years. A logistic regression model was built incorporating variables from patient demographics, surgical technique, articular cartilage injuries, and meniscus tears/treatment to determine the predictors (risk factors) of IKDC, KOOS, and Marx at 6 years. Results We completed a minimum follow-up on 86% (1307/1512) of our cohort at 6 years. The cohort was 56% male, had a median age of 23 years at the time of enrollment, with 76% reporting a non-contact injury mechanism. Incidence of concomitant pathology at the time of surgery consisted of the following: articular cartilage (medial femoral condyle [MFC]-25%, lateral femoral condyle [LFC]-20%, medial tibial plateau [MTP]-6%, lateral tibial plateau [LTP]-12%, patella-20%, trochlear-9%) and meniscal (medial-38%, lateral-46%). Both articular cartilage lesions and meniscal tears were significant predictors of 6-year outcomes on IKDC and KOOS. Grade 3 or 4 articular cartilage lesions (excluding patella) significantly reduced IKDC and KOOS scores at 6 years. IKDC demonstrated worse outcomes with the presence of a grade 3-4 chondral lesion on the MFC, MTP, and LFC. Likewise, KOOS was negatively affected by cartilage injury. The sole significant predictor of reduced Marx activity was the presence of a grade 4 lesion

  4. Fixed-time induction of ovulation in camels superovulated by different eCG modalities during the transition period in Egypt : Superovulation in camels during the transition period.

    PubMed

    Khalifa, Marwa Ahmed; Rateb, Sherif Abdel-Razzak; El-Bahrawy, Khalid Ahmed

    2016-04-01

    The current investigation aimed to establish a fixed-time induction of ovulation/ insemination protocol in camels superovulated by different equine chorionic gonadotropin (eCG) regimens during the transition period in Egypt (mid-October to mid-November). Seventeen pluriparous camels, Camelus dromedarius, were used. All females retained controlled intra-vaginal drug releasers (CIDRs) for 13 consecutive days, and at CIDR withdrawal, the camels were randomly divided into three groups. The control group (n = 5) received 1 ml saline intra-muscularly (i.m.), whereas remaining camels were superovulated by 2500 IU eCG either in a single shot (SS, n = 6) or in serial decreasing doses over 3 days (DD, n = 6). Ovarian dynamics were monitored by transrectal ultrasonography at 2-day intervals, and ovulation was induced by 5000 IU hCG i.m. The changes in reproductive hormones throughout the period of the study were determined. The results showed that mean values of total no. of follicles and size of dominant follicles remained low (P < 0.05) in all groups until day of CIDR removal. Thereafter, total follicle no. increased (P < 0.05) in both superovulated groups compared to the control, where the dominant follicles attained the highest (P < 0.05) diameter 12 days after the eCG treatment. Double-ovulation rate was higher (P < 0.05) in SS (50%) and DD (66.6%) groups compared to that of control (0.0%). However, 33.3% of the SS group developed large anovulatory follicles (ø > 25 mm), which did not respond to induction to ovulation. These results elucidate that eCG administration in serial decreasing doses generates a reliable superovulatory response in camels, and ovulation can be blindly induced 12 days after the gonadotropin treatment. This fixed-time hormonal protocol represents a sufficient alternative to conventional day-to-day ultrasonography and would have profound implication for enhanced fertility in dromedary camels by facilitating infield application of embryo transfer

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

    NASA Technical Reports Server (NTRS)

    Weng, Hengyi; Lau, K.-M.

    1994-01-01

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

  6. Nonparametric decomposition of quasi-periodic time series for change-point detection

    NASA Astrophysics Data System (ADS)

    Artemov, Alexey; Burnaev, Evgeny; Lokot, Andrey

    2015-12-01

    The paper is concerned with the sequential online change-point detection problem for a dynamical system driven by a quasiperiodic stochastic process. We propose a multicomponent time series model and an effective online decomposition algorithm to approximate the components of the models. Assuming the stationarity of the obtained components, we approach the change-point detection problem on a per-component basis and propose two online change-point detection schemes corresponding to two real-world scenarios. Experimental results for decomposition and detection algorithms for synthesized and real-world datasets are provided to demonstrate the efficiency of our change-point detection framework.

  7. Lower thermospheric density fluctuations during the time period of Typhoon Dinah

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Tsao, Y. D.; Johnson, D. L.; Chen, A. J.; Liu, J. M.

    1989-01-01

    High frequency Doppler sounder arrays were used to study the thermospheric density fluctuations caused by Typhoon Dinah in August, 1987. The results show that the maximum density fluctuations caused by the typhoon at altitudes of 150 to 350 km were close to + or - 30 percent deviation from the quiet background. The time-dependent density fluctuations were in phase with the horizontal phase velocity of major gravity waves excited by the storm. It is suggested that the study demonstrates the use of HF Doppler sounder measurement of gravity waves, horizontal wind velocity in the direction of gravity wave propagation, and density perturbations at thermospheric heights.

  8. High-order fuzzy time-series based on multi-period adaptation model for forecasting stock markets

    NASA Astrophysics Data System (ADS)

    Chen, Tai-Liang; Cheng, Ching-Hsue; Teoh, Hia-Jong

    2008-02-01

    Stock investors usually make their short-term investment decisions according to recent stock information such as the late market news, technical analysis reports, and price fluctuations. To reflect these short-term factors which impact stock price, this paper proposes a comprehensive fuzzy time-series, which factors linear relationships between recent periods of stock prices and fuzzy logical relationships (nonlinear relationships) mined from time-series into forecasting processes. In empirical analysis, the TAIEX (Taiwan Stock Exchange Capitalization Weighted Stock Index) and HSI (Heng Seng Index) are employed as experimental datasets, and four recent fuzzy time-series models, Chen’s (1996), Yu’s (2005), Cheng’s (2006) and Chen’s (2007), are used as comparison models. Besides, to compare with conventional statistic method, the method of least squares is utilized to estimate the auto-regressive models of the testing periods within the databases. From analysis results, the performance comparisons indicate that the multi-period adaptation model, proposed in this paper, can effectively improve the forecasting performance of conventional fuzzy time-series models which only factor fuzzy logical relationships in forecasting processes. From the empirical study, the traditional statistic method and the proposed model both reveal that stock price patterns in the Taiwan stock and Hong Kong stock markets are short-term.

  9. The evaluation of mood condition among depressed adolescent students in Isfahan after 6 years

    PubMed Central

    Shakibaei, Fereshteh; Alikhani, Mahmood; Mahaki, Behzad; Sichani, Naeimeh Karimian; Tabatabaei, Haleh Dormiani

    2016-01-01

    Background: This study has carried out to find the recovery rate, depression recurrence, changing of diagnose into bipolar mood disorder (BMD) and appearing other psychiatric disorders including obsessive compulsive disorder, oppositional defiant disorder (ODD), substance induced disorders, attention deficit and hyperactivity disorder, and anxiety disorders after 6 years among students having major depression disorder in Isfahan and its relation to some demographic factors. Materials and Methods: In this historical cohort study, 278 students studying in guidance school, in 2006 being 11–16-year-old and were diagnosed to have major depressive disorder participated. Data collection was done by completing children depression on inventory, Young Maria Rating Scale and also final diagnosis determination through interview by psychiatrists. To analyze the data, in addition to use descriptive statistics, multinomial and multiple logistic regressions were used to evaluate the relationships. All the analyses were done using SPSS 20. Results: About 34.9 of adolescents have suffered from depression after 6 years. Depression in 12.2% has been changed into BMD. The BMD morbidity chance was less in girls rather than depression one. The ratio of drug abuse in girls was less than boys (odds ratio [OR] = 0.471, P = 0.046). Students received no treatment or only pharmacotherapy, were more caught by ODD in comparison with those cases who received both pharmacotherapy and psychotherapy (P = 0.005, 0.038 and OR = 4.29 and 5.88). Conclusion: About half of students after 6 years are caught by depression or BMD. It reveals the importance of this disorder and its role in making behavioral problems for adolescents in their future. PMID:27308266

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  11. Identifying parameters of multi-degree-of-freedom nonlinear structural dynamic systems using linear time periodic approximations

    NASA Astrophysics Data System (ADS)

    Sracic, Michael W.; Allen, Matthew S.

    2014-06-01

    The authors recently presented a new nonlinear system identification method, here dubbed the NL-LTP method, in which the system of interest is forced harmonically so that it responds in a stable periodic orbit, and then it is perturbed slightly and its response is recorded as it returns to the orbit. Under mild assumptions the response about the periodic orbit can be approximated using a linear time periodic system model, which can be identified from the measurements using techniques that are akin to linear modal analysis. While the prior work focused on simulated measurements from single degree-of-freedom systems, this work presents several tools that are needed in order to use this approach on multi-degree-of-freedom systems and focuses on applying the method to experimental hardware. The proposed system identification methodology is unique in that it identifies both the order of the nonlinear system and a mathematical model for the nonlinear restoring forces without assuming the mathematical form for the nonlinearities a priori. Towards these ends, this work explains how to extract the underlying nonlinear system model, or nonlinear restoring force versus displacement relationships, from the time periodic model that governs deviations of the system from its periodic orbit, and presents various metrics that can be used to determine which terms in the model are meaningful. These new tools are used to apply the identification method to a continuous, multi-degree-of-freedom structure with a discrete geometric nonlinearity, using both simulated and experimental measurements. The experimental hardware consists of a cantilever beam with a nonlinear spring attached to its tip, which is driven in a periodic limit cycle by an electromagnetic shaker.

  12. Work Incapacity and Treatment Costs After Severe Accidents: Standard Versus Intensive Case Management in a 6-Year Randomized Controlled Trial.

    PubMed

    Scholz, Stefan M; Andermatt, Peter; Tobler, Benno L; Spinnler, Dieter

    2016-09-01

    Purpose Case management is widely accepted as an effective method to support medical rehabilitation and vocational reintegration of accident victims with musculoskeletal injuries. This study investigates whether more intensive case management improves outcomes such as work incapacity and treatment costs for severely injured patients. Methods 8,050 patients were randomly allocated either to standard case management (SCM, administered by claims specialists) or intensive case management (ICM, administered by case managers). These study groups differ mainly by caseload, which was approximately 100 cases in SCM and 35 in ICM. The setting is equivalent to a prospective randomized controlled trial. A 6-year follow-up period was chosen in order to encompass both short-term insurance benefits and permanent disability costs. All data were extracted from administrative insurance databases. Results Average work incapacity over the 6-year follow-up, including contributions from daily allowances and permanent losses from disability, was slightly but insignificantly higher under ICM than under SCM (21.6 vs. 21.3 % of pre-accident work capacity). Remaining work incapacity after 6 years of follow-up showed no difference between ICM and SCM (8.9 vs. 8.8 % of pre-accident work incapacity). Treatment costs were 43,500 Swiss Francs (CHF) in ICM compared to 39,800 in SCM (+9.4 %, p = 0.01). The number of care providers involved in ICM was 10.5 compared to 10.0 in ICM (+5.0 %, p < 0.001). Conclusions Contrary to expectations, ICM did not reduce work incapacity as compared to SCM, but did increase healthcare consumption and treatment costs. It is concluded that the intensity of case management alone is not sufficient to improve rehabilitation and vocational reintegration of accident victims. PMID:26687330

  13. A Case of Infantile Kyrle-Flegel Disease in a 6-Year-Old Yemeni Girl.

    PubMed

    Alshami, Mohammad Ali; Mohana, Mona Jameel

    2016-01-01

    Kyrle disease (KD) and Flegel disease (FD) are rare variants of primary perforating dermatoses, characterized by transepidermal elimination of abnormal endogenous materials. We describe a 6-year-old Yemeni girl with a 2-year history of generalized asymptomatic, small, reddish-brown keratotic papules with a lenticular central keratotic plug. Although these features are synonymous with FD, the histology of a punch biopsy was consistent with KD. The patient was otherwise healthy, and no family members had a history of similar diseases. The patient was diagnosed with KD-FD, owing to the manifestation of features associated with both diseases. PMID:26933407

  14. [Extreme reactive thrombocytosis in a healthy 6 year-old child].

    PubMed

    de Lama Caro-Patón, G; García-Salido, A; Iglesias-Bouzas, M I; Guillén, M; Cañedo-Villaroya, E; Martínez-Romera, I; Serrano-González, A; Casado-Flores, J

    2014-11-01

    Thrombocytosis is usually a casual finding in children. Reactive or secondary thrombocytosis is the more common form, being the infections diseases the most prevalent cause of it. Regarding the number of platelets there are four degrees of thrombocytosis; in its extreme degree the number of platelets exceeds 1,000,000/mm(3). We describe a case of extreme reactive thrombocytosis in a healthy 6-year-old child. He required critical care admission for diagnosis and treatment (maximum number of platelets 7,283,000/mm(3)). We review the different causes of thrombocytosis in childhood, the differential diagnosis, and the available treatments in case of extreme thrombocytosis. PMID:24315421

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

    NASA Astrophysics Data System (ADS)

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

    2000-10-01

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

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

    PubMed

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

    1999-07-01

    Determining blood pressure (BP) values at different daily time periods is a well recognised measure to assess the risk of end-organ damage. However, the use of various definitions of these periods, eg, day vs night, sleep vs wake or arbitrary definitions, makes clinical decisions based on available data difficult. In the present study, we compared BP loads in actual sleep-wake periods to default day-night definition provided by the ambulatory BP monitoring (ABPM) software (day 06.00-22.00; night 22.00-06.00) as well as to an arbitrary definition of sleep-wake periods in children published in Journal of Pediatrics (Soergel et al, 1997) (awake 08.00-20:00 and sleep 00.00-06.00). We used an actigraph, an accelerometer, to define the actual sleep-wake periods in 46 patients with essential hypertension who are on various treatment regimens. BP data were obtained by using Spacelabs 90207 monitors for a full 24 hours. There were significant differences between actual sleep-wake and default definition for BP load. No similar findings were noted when arbitrary definition was used. The proportion of hypertensives was not significantly different when default and arbitrary definitions were used. Classification of dippers and non-dippers is greatly affected by the definition of sleep interval using the default method. Although some of the misclassifications were not statistically significant, their clinical importance must be considered. Determination of sleep and wake periods for analysis of ABPM data should be based on careful determination of actual periods. Using other definitions may not provide complete information or accommodate for individual variation. PMID:10449208

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

    PubMed

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

    1999-11-01

    Determining blood pressure (BP) values at different daily time periods is a well recognised measure to assess the risk of end-organ damage. However, the use of various definitions of these periods, eg, day vs night, sleep vs wake or arbitrary definitions, makes clinical decisions based on available data difficult. In the present study, we compared BP loads in actual sleep-wake periods to default day-night definition provided by the ambulatory BP monitoring (ABPM) software (day 06.00 to 22.00; night 22.00 to 06.00) as well as to an arbitrary definition of sleep-wake periods in children published in Soergel et al (J Pediatr 1997; 130: 178-184)1 (awake 08.00 to 20.00 and sleep 00.00 to 06.00. We used an actigraphy, an accelerometer, to define the actual sleep-wake periods in 46 patients with essential hypertension who are on various treatment regimens. BP data was obtained by using Spacelabs 90207 monitors for a full 24 h. There were significant differences between actual sleep-wake and default definition for BP load. No similar finding was noted when arbitrary definition was used. The proportion of hypertensives was not significantly different when default and arbitrary definitions were used. Classification of dippers and non-dippers is greatly affected by the definition of sleep interval using the default method. Although some of the misclassifications were not statistically significant, their clinical importance must be considered. Determination of sleep and wake periods for analysis of ABPM data should be based on careful determination of actual periods. Using other definitions may not provide complete information or accommodate for individual variation. PMID:10578220

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

    PubMed Central

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

    2016-01-01

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

  19. Analysis of 6-year fluid electric conductivity logs to evaluate the hydraulic structure of the deep drill hole at Outokumpu, Finland

    NASA Astrophysics Data System (ADS)

    Sharma, Prabhakar; Tsang, Chin-Fu; Kukkonen, Ilmo T.; Niemi, Auli

    2015-11-01

    Over the last two decades, the flowing fluid electric conductivity (FFEC) logging method has been applied in boreholes in the well-testing mode to evaluate the transmissivity, hydraulic head, and formation water electrical conductivity as a function of depth with a resolution of about 10-20 cm. FFEC profiles along the borehole are obtained under both shut-in and pumping conditions in a logging procedure that lasts only 3 or 4 days. A method for analyzing these FFEC logs has been developed and successfully employed to obtain formation parameters in a number of field studies. The present paper concerns the analysis of a unique set of FFEC logs that were taken from a deep borehole reaching down to 2.5 km at Outokumpu, Finland, over a 6-year time period. The borehole intersects paleoproterozoic metasedimentary, granitoid, and ophiolite-derived rocks. After the well was drilled, completed, and cleaned up, FFEC logs were obtained after 7, 433, 597, 948, and 2036 days. In analyzing these five profiles, we discovered the need to account for salinity diffusion from water in the formation to the borehole. Analysis results include the identification of 15 hydraulically conducting zones along the borehole, the calculation of flow rates associated with these 15 zones, as well as the estimation of the variation of formation water electrical conductivity as a function of depth. The calculated flow rates were used to obtain the tentative hydraulic conductivity values at these 15 depth levels.

  20. Analysis of 6-year fluid electric conductivity logs to evaluate the hydraulic structure of the deep drill hole at Outokumpu, Finland

    NASA Astrophysics Data System (ADS)

    Sharma, Prabhakar; Tsang, Chin-Fu; Kukkonen, Ilmo T.; Niemi, Auli

    2016-07-01

    Over the last two decades, the flowing fluid electric conductivity (FFEC) logging method has been applied in boreholes in the well-testing mode to evaluate the transmissivity, hydraulic head, and formation water electrical conductivity as a function of depth with a resolution of about 10-20 cm. FFEC profiles along the borehole are obtained under both shut-in and pumping conditions in a logging procedure that lasts only 3 or 4 days. A method for analyzing these FFEC logs has been developed and successfully employed to obtain formation parameters in a number of field studies. The present paper concerns the analysis of a unique set of FFEC logs that were taken from a deep borehole reaching down to 2.5 km at Outokumpu, Finland, over a 6-year time period. The borehole intersects paleoproterozoic metasedimentary, granitoid, and ophiolite-derived rocks. After the well was drilled, completed, and cleaned up, FFEC logs were obtained after 7, 433, 597, 948, and 2036 days. In analyzing these five profiles, we discovered the need to account for salinity diffusion from water in the formation to the borehole. Analysis results include the identification of 15 hydraulically conducting zones along the borehole, the calculation of flow rates associated with these 15 zones, as well as the estimation of the variation of formation water electrical conductivity as a function of depth. The calculated flow rates were used to obtain the tentative hydraulic conductivity values at these 15 depth levels.

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  2. 3D pseudospectral time domain for modeling second-harmonic generation in periodically poled lithium niobate ridge-type waveguides

    NASA Astrophysics Data System (ADS)

    Devaux, Fabrice; Lantz, Eric; Chauvet, Mathieu

    2016-04-01

    We report an application of the tri-dimensional pseudo-spectral time domain algorithm, that solves with accuracy the nonlinear Maxwell's equations, to predict second harmonic generation in lithium niobate ridge-type waveguides with high index contrast. Characteristics of the nonlinear process such as conversion efficiency as well as impact of the multimode character of the waveguide are investigated as a function of the waveguide geometry in uniformly and periodically poled medium.

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  4. Maternal self-efficacy and feeding practices in children aged 3-6 years

    PubMed Central

    Doaei, Saeid; Gholamalizadeh, Maryam; Entezari, Mohammad Hassan

    2015-01-01

    Objective: Nutrition in childhood has an important role in current and adulthood health. Recent studies have shown that the mother’s lifestyle has an important role in the methods used by mother to feed child. This paper aimed to investigate the association between mother’s weight efficacy lifestyle with feeding practices in children aged 3- 6 years. Materials and Methods: In this cross-sectional study which was carried out in 30 primary schools of Rasht (Iran) in 2012, 165 mothers with children aged 3-6 years were participated. Mothers reported their own and their child’s demographics. Aspects of mother’s weight efficacy lifestyle and mother’s control practices were assessed using Weight Efficacy Lifestyle (WEL) questionnaire and Comprehensive Feeding Practices questionnaire (CFPQ) respectively. Height and weight of mothers participated in the study were measured. The role of mother’s weight efficacy in predicting child’s feeding practices was assessed using linear regression. Results: Results showed that mother’s weight efficacy was related to child feeding practices. The mothers with similar weight efficacy lifestyle applied similar methods in child nutrition. Mothers with better weight efficacy used more encourage balance and variety, environmental control, child involvement and less emotion regulation using foods. Conclusion: ‎ ‏ ‏‎ The result of the ‎study showed that maternal ‎lifestyle was associated with ‎child feeding practices.‎ PMID:27006673

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  6. On the evaluation of the time of periodical dissolution of a dispersed material in a rotor-pulse device

    NASA Astrophysics Data System (ADS)

    Fedorov, A. V.; Shul'Gin, A. V.; Vasilishin, M. S.; Ivanova, D. B.; Ivanov, O. S.; Karpov, A. G.

    2011-07-01

    Results are presented of experimental and numerical investigations of the kinetics of periodical dissolution of benzoic and salicylic acids in water using the rotor-pulse device. It is found that the process obeys the firstorder kinetics. A determining influence of the rotation frequency of the device rotor and the size of the radial gap between the rotor and the stator on the dissolution time is shown. Favorable agreement between the experimental and calculated time dependences for the concentration of the dissolved substance are obtained.

  7. Assessment of working memory components at 6years of age as predictors of reading achievements a year later.

    PubMed

    Nevo, Einat; Breznitz, Zvia

    2011-05-01

    The ability of working memory skills (measured by tasks assessing all four working memory components), IQ, language, phonological awareness, literacy, rapid naming, and speed of processing at 6years of age, before reading was taught, to predict reading abilities (decoding, reading comprehension, and reading time) a year later was examined in 97 children. Among all working memory components, phonological complex memory contributed most to predicting all three reading abilities. A capacity measure of phonological complex memory, based on passing a minimum threshold in those tasks, contributed to the explained variance of decoding and reading comprehension. Findings suggest that a minimal ability of phonological complex memory is necessary for children to attain a normal reading level. Adding assessment of phonological complex memory, before formal teaching of reading begins, to more common measures might better estimate children's likelihood of future academic success. PMID:21115182

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

    PubMed Central

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

    2010-01-01

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

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

    PubMed Central

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

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

  11. Design and analysis strategies for digital repetitive control systems with time-varying reference/disturbance period

    NASA Astrophysics Data System (ADS)

    Costa-Castelló, R.; Olm, J. M.; Ramos, G. A.

    2011-07-01

    This article analyses stability and performance features of different design schemes for digital repetitive control systems subject to references/disturbances that exhibit non-uniform frequency. Aiming at maintaining a constant value for the ratio T p /T s , T p being the period of the reference/disturbance signal and T s being the sampling period, two approaches are proposed. The first one deals with the real-time adaptation of T s to the actual changes of T p ; stability is studied by means of an LMI gridding method and also using robust control techniques. The second one propounds the introduction of an additional compensator that annihilates the effect of the time-varying sampling in the closed-loop system and forces its behaviour to coincide with that of an a priori selected nominal sampling period; the internal stability of the compensator-plant subsystem is checked by means of LMI gridding. The theoretical results are experimentally tested and compared through a mechatronic plant model.

  12. Discrete infinite-dimensional type-K monotone dynamical systems and time-periodic reaction-diffusion systems

    NASA Astrophysics Data System (ADS)

    Liang, Xing; Jiang, Jifa

    The asymptotic behavior of discrete type-K monotone dynamical systems and reaction-diffusion equations is investigated. The studying content includes the index theory for fixed points, permanence, global stability, convergence everywhere and coexistence. It is shown that the system has a globally asymptotically stable fixed point if every fixed point is locally asymptotically stable with respect to the face it belongs to and at this point the principal eigenvalue of the diagonal partial derivative about any component not belonging to the face is not one. A nice result presented is the sufficient and necessary conditions for the system to have a globally asymptotically stable positive fixed point. It can be used to establish the sufficient conditions for the system to persist uniformly and the convergent result for all orbits. Applications are made to time-periodic Lotka-Volterra systems with diffusion, and sufficient conditions for such systems to have a unique positive periodic solution attracting all positive initial value functions are given. For more general time-periodic type-K monotone reaction-diffusion systems with spatial homogeneity, a simple condition is given to guarantee the convergence of all positive solutions.

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

    PubMed

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

    2015-01-01

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

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

    PubMed Central

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

    2015-01-01

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

  15. Alcohol Consumption and Liver Disease in Australia: A Time Series Analysis of the Period 1935–2006

    PubMed Central

    Jiang, Heng; Livingston, Michael; Room, Robin; Dietze, Paul; Norström, Thor; Kerr, William C.

    2014-01-01

    Aims: The aim of the study was to examine for Australia whether the link between population alcohol consumption and liver disease mortality varies over time, using 71 years of data. Methods: Overall and gender-specific rates of liver disease mortality were analysed in relation to total alcohol consumption as well as for different beverage types by using autoregressive integrated moving average (ARIMA) time series methods. Separate models were developed for the entire time period and for two sub-periods (1935–1975, 1976–2006). Results: A 1-l increase in adult per capita consumption of pure alcohol led to a rise of ∼10% in overall liver disease mortality rates and a 11 and 9% increase in female and male liver disease mortality, respectively. The strength of the relationship between per capita consumption and liver disease mortality diminished over time. Spirits consumption was found to be the main driving factor in liver mortality rates between 1935 and 1975, while beer consumption was found to be the most significant predictor in liver diseases in the last three decades. In a comparative perspective, the effect of per capita alcohol consumption on liver disease in Australia is similar to the USA, Southern and Eastern Europe countries, but weaker than in Canada and western European countries. Conclusion: An increase in per capita alcohol consumption in Australia is likely to lead to an increase in liver disease. Changes in the most important beverage over the study period suggest substantial shifts in drinking patterns and preferences among the heaviest Australian drinkers. PMID:24052533

  16. Precocious puberty presenting with menarche at the age of 6 years - a case report.

    PubMed

    Banu, J; Sultana, P; Chowdhury, M A

    2014-07-01

    Precocious puberty or central precocious puberty can be very confusing and truly unexpected. After all who know children could go into puberty too early? There is treatment for this condition. Present report has stated that central precocious puberty is becoming more frequent. Many factors may contribute to children who exhibit signs of early precocious puberty. Here we are reporting a case of premature menarche of 6 years old girl who initially presented with continuous per vaginal bleeding for 3 months as a onset of menarche later on after clinical examination and investigations she was diagnosed a precocious puberty due to juvenile premature hypothyroidism. After the successful treatment with thyroxin, level of TSH gradually was decreased and subsequently normal. There after per vaginal bleeding stopped and clinically improved. PMID:25178615

  17. Phthiriasis palpebrarum misdiagnosed as allergic blepharoconjunctivitis in a 6-year-old girl.

    PubMed

    Yi, Jun Wen; Li, Li; Luo, Da Wei

    2014-01-01

    Phthiriasis palpebrarum is an infestation of the eyelashes caused by the louse Pthirus pubis (Linnaeus, 1758). We report a case of phthiriasis palpebrarum in a 6-year-old girl, which was initially misdiagnosed as allergic blepharoconjunctivitis. Parasites and their nits were found adhering to the eyelashes and eyelids of her right eye as well as scalp hairs. No abnormality was found in the left eye. The histopathology exam revealed the presence of adults and eggs of Pthirus pubis. We mechanically removed all the eyelashes of the right eye at their base, with lice and nits. The scalp was shaved and washed with phenothrin shampoo. No recurrence was found during 3 months of follow-up. Removal of the eyelashes, cutting of scalp hairs, and phenothrin shampoo may be effective in treating phthiriasis palpebrarum. In cases of blepharoconjunctivitis, eyelids and eyelashes should be carefully examined by slit lamp to avoid misdiagnosis. PMID:24909484

  18. Psammomatoid juvenile ossifying fibroma of mandible in a 6-year-old child.

    PubMed

    Manjunatha, B S; Purohit, Sharad; Kiran, Sheetal; Mahita, V Naga

    2016-01-01

    Juvenile ossifying fibroma (JOF) is a rare fibro-osseous lesion of the jaw occurs at the early age of onset frequently under 15 years with a propensity to recur. It appears as a unilobulated/multilobulated lesion at an early stage followed by radiopaque appearance surrounded by radiolucent rimming at advanced stages. The psammomatous type of JOF (PsJOF) principally involves the bones of the orbit and paranasal sinuses. However in some cases, maxilla or rarely the mandible may be pretentious. Here, we report a challenging case of PsJOF in a 6-year-old child with a complaint of swelling imitating a cystic lesion in left back region of the lower jaw for 2 months. The authors propose that a careful examination and correlations of clinical, radiological, and histopathological features are essential to arrive at correct diagnosis and play a vital role in management of such patients. PMID:27134454

  19. Psammomatoid juvenile ossifying fibroma of mandible in a 6-year-old child

    PubMed Central

    Manjunatha, B. S.; Purohit, Sharad; Kiran, Sheetal; Mahita, V. Naga

    2016-01-01

    Juvenile ossifying fibroma (JOF) is a rare fibro-osseous lesion of the jaw occurs at the early age of onset frequently under 15 years with a propensity to recur. It appears as a unilobulated/multilobulated lesion at an early stage followed by radiopaque appearance surrounded by radiolucent rimming at advanced stages. The psammomatous type of JOF (PsJOF) principally involves the bones of the orbit and paranasal sinuses. However in some cases, maxilla or rarely the mandible may be pretentious. Here, we report a challenging case of PsJOF in a 6-year-old child with a complaint of swelling imitating a cystic lesion in left back region of the lower jaw for 2 months. The authors propose that a careful examination and correlations of clinical, radiological, and histopathological features are essential to arrive at correct diagnosis and play a vital role in management of such patients. PMID:27134454

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

    PubMed

    Li, Hongfei; Jiang, Haijun; Hu, Cheng

    2016-03-01

    In this paper, we investigate a class of memristor-based BAM neural networks with time-varying delays. Under the framework of Filippov solutions, boundedness and ultimate boundedness of solutions of memristor-based BAM neural networks are guaranteed by Chain rule and inequalities technique. Moreover, a new method involving Yoshizawa-like theorem is favorably employed to acquire the existence of periodic solution. By applying the theory of set-valued maps and functional differential inclusions, an available Lyapunov functional and some new testable algebraic criteria are derived for ensuring the uniqueness and global exponential stability of periodic solution of memristor-based BAM neural networks. The obtained results expand and complement some previous work on memristor-based BAM neural networks. Finally, a numerical example is provided to show the applicability and effectiveness of our theoretical results. PMID:26752438

  1. How does the non-linear estimation of periodic terms improve the detection of offsets in GNSS position time series?

    NASA Astrophysics Data System (ADS)

    Collilieux, Xavier; Lebarbier, Emilie; Coulot, David; Bernard, Etienne

    2014-05-01

    GNSS position time series computed from permanent station observations have been shown to be affected by a significant number of offsets that can be explained (equipment changes, antenna malfunction, earthquakes) or not. If not corrected, velocities or inter-annual signals estimated from the series will be biased. In addition to these offsets, GNSS position series show dominant periodic signals at seasonal and specific frequencies related to real ground displacements or systematic errors. As a consequence, it is relevant to estimate both the frequencies of the periodic signals and the positions of the offsets. This supplies a synthetic description of the series and should improve the velocity determination. In this poster, we propose to study two methods that rely on two different approaches on real and synthetic series in order to solve this problem. We then propose to quantify if the estimation of low-frequency signals could help to improve the offsets detection.

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  3. Proportional spike-timing precision and firing reliability underlie efficient temporal processing of periodicity and envelope shape cues

    PubMed Central

    Zheng, Y.

    2013-01-01

    Temporal sound cues are essential for sound recognition, pitch, rhythm, and timbre perception, yet how auditory neurons encode such cues is subject of ongoing debate. Rate coding theories propose that temporal sound features are represented by rate tuned modulation filters. However, overwhelming evidence also suggests that precise spike timing is an essential attribute of the neural code. Here we demonstrate that single neurons in the auditory midbrain employ a proportional code in which spike-timing precision and firing reliability covary with the sound envelope cues to provide an efficient representation of the stimulus. Spike-timing precision varied systematically with the timescale and shape of the sound envelope and yet was largely independent of the sound modulation frequency, a prominent cue for pitch. In contrast, spike-count reliability was strongly affected by the modulation frequency. Spike-timing precision extends from sub-millisecond for brief transient sounds up to tens of milliseconds for sounds with slow-varying envelope. Information theoretic analysis further confirms that spike-timing precision depends strongly on the sound envelope shape, while firing reliability was strongly affected by the sound modulation frequency. Both the information efficiency and total information were limited by the firing reliability and spike-timing precision in a manner that reflected the sound structure. This result supports a temporal coding strategy in the auditory midbrain where proportional changes in spike-timing precision and firing reliability can efficiently signal shape and periodicity temporal cues. PMID:23636724

  4. Changes in caries experience among 6-year-olds in Blekinge, Sweden between 1994 and 2000.

    PubMed

    Holst, Annalena; Braune, Karin; Kjellberg, Maria

    2004-01-01

    For 6-year-old children in the County of Blekinge, the goal was that > 65 percent should have dmft = 0 in the year 2000. To formulate this goal a study on prevalence and distribution of caries in 6-year-old children was performed in 1994. The aim of the present study was to evaluate whether the dental health goal for the year 2000 was achieved and compare clinical data regarding oral status in children in 1994 and in 2000. The material comprised a random sample of 225 children. The studyfrom year 1994, which included 213 children, was repeated. A clinical investigation was performed and completed with bite-wing radiographs on individual indication, whenever the proximal surfaces could not be inspected clinically due to close and broad contact. In addition, the parents were asked questions about toothbrushing and use of fluoride tablets. 53 percent of the children showed healthy teeth with no initial caries lesions or restorations compared to 35 percent in 1994. The pattern of dental health was still very skewed among the children. The children with nine or more decayed surfaces increased from 2 percent in 1994 to almost 4 percent in 2000. The number of fissure sealings performed had increased between 1994 and 2000 by almost 50 percent in both primary molars and first permanent molars. However,the use of fluoride tablets had decreased from 20 percent in 1994 to 7 percent of the children in 2000. The data showed a decline in prevalence of dmf teeth and an increase in the percent of caries-free children but the difference was not significant on the 5% level. However, as 47% of the children were in need of restorative treatment, our dental health goal was not achieved. We also recommend that our preventive program with focus on primary prevention and individual risk assessment should also be targeted at the whole population of pre-school children and their parents. PMID:15506690

  5. Breastfeeding and Later Psychosocial Development of Children at 6 Years of Age

    PubMed Central

    Li, Ruowei; Perrine, Cria G.; Schieve, Laura A.

    2014-01-01

    OBJECTIVE: To examine the association of breastfeeding duration with psychosocial development at 6 years of age. METHODS: We analyzed data from the 2005–2007 Infant Feeding Practices Study II and its 2012 Year 6 Follow-Up (N = 1442). Our breastfeeding duration variable combined overall and exclusive breastfeeding reported during infancy (never breastfed, breastfed <6 months, breastfed ≥6 months + exclusive breastfeeding <3 months, and breastfed ≥6 months + exclusive breastfeeding ≥3 months). Maternal responses to the Strengths and Difficulties Questionnaire were used to create our child psychosocial outcome domains (emotional symptoms, conduct problems, hyperactivity, peer problems, prosocial behavior, and total difficulties). Separate multivariable logistic regression models controlling for maternal sociodemographic characteristics, maternal mental health, and child characteristics were used to assess the likelihood of having difficulties on the 6 domains based on breastfeeding duration. RESULTS: Compared with children who were never breastfed, those who were breastfed for ≥6 months and exclusively breastfed for ≥3 months had decreased odds of difficulties with emotional symptoms (odds ratio [OR]: 0.52; 95% confidence interval [CI]: 0.27–0.99), conduct problems (OR: 0.24; 95% CI: 0.10–0.54), and total difficulties (OR: 0.39; 95% CI: 0.18–0.85) before adjustment. These associations were no longer significant after adjustment. CONCLUSIONS: Although in our unadjusted analyses we observed significant associations between breastfeeding duration and later psychosocial development, including decreased odds of emotional, conduct, and total difficulties at 6 years of age, these findings were no longer detectable after adjusting for the many potential confounding factors that play a role in psychosocial development. PMID:25183753

  6. Changes in BMI over 6 years: the role of demographic and neighborhood characteristics

    PubMed Central

    Berry, TR; Spence, JC; Blanchard, C; Cutumisu, N; Edwards, J; Nykiforuk, C

    2016-01-01

    Objective To undertake a 6-year longitudinal investigation of the relationship between the built environment (perceived and objectively measured) and change in body mass index (BMI). Specifically, this research examined whether change in BMI was predicted by objectively measured neighborhood walkability and socioeconomic status (SES), and perceived neighborhood characteristics (for example, crime, traffic and interesting things to look at) in addition to other factors such as age, gender, education, physical activity, fruit and vegetable consumption and smoking. Design Longitudinal study Subjects 500 adults who provided complete data in 2002 and 2008 and who did not move over the course of the study (47.8% female; age in 2002: 18–90 years). Measurements Telephone surveys in 2002 and 2008 measuring perceptions of their neighborhood environment and demographic factors. Objective measures of neighborhood characteristics were calculated using census data and geographical information systems in 2006. Results Age, neighborhood SES and perceived traffic were significantly related to increased BMI over the 6 years. Younger participants and those in lower SES neighborhoods were more likely to have increased BMI. Agreement with the statement that traffic made it difficult to walk also predicted increased BMI. Conclusion This study adds to the literature to show that BMI increased in low SES neighborhoods. Although more research is needed to fully understand how neighborhood SES contributes to obesity, it is without question that individuals in socially disadvantaged neighborhoods face more barriers to health than their wealthier counterparts. This study also calls into question the relationship between walkability and changes in BMI and emphasizes the necessity of longitudinal data rather than relying on cross-sectional research. PMID:20157324

  7. Reliability and Validity of "Parents' Evaluation of Responsible Behaviors of 5-6 Year Old Children" Scale

    ERIC Educational Resources Information Center

    Polat, Ozgul; Dagal, Asude B.

    2013-01-01

    This study is aimed at developing a scale (Parents' Evaluation of Responsible Behaviors of 5-6 Year Old Children) for measuring parents' evaluation of their 5-6 year-old children's responsible behaviors. The construct validity of the scale was tested by Factor Analysis. Factor analysis determined that the scale can be clustered under 10 factors.…

  8. Children's Judgments of Emotion from Conflicting Cues in Speech: Why 6-Year-Olds Are So Inflexible

    ERIC Educational Resources Information Center

    Waxer, Matthew; Morton, J. Bruce

    2011-01-01

    Six-year-old children can judge a speaker's feelings either from content or paralanguage but have difficulty switching the basis of their judgments when these cues conflict. This inflexibility may relate to a lexical bias in 6-year-olds' judgments. Two experiments tested this claim. In Experiment 1, 6-year-olds (n = 40) were as inflexible when…

  9. Recurrent acute-onset Cushing's syndrome 6 years after removal of a thymic neuroendocrine carcinoma: from ectopic ACTH to CRH.

    PubMed

    Schalin-Jäntti, Camilla; Asa, Sylvia L; Arola, Johanna; Sane, Timo

    2013-03-01

    We describe a rare case of ectopic Cushing's syndrome that recurred 6 years after resection of a thymic neuroendocrine carcinoma. We discuss reasons for the differing clinical presentations, management, hormone profiles, as well as immunopathology. A 41-year-old male developed acute-onset Cushing's syndrome. Clinical presentation and laboratory results were compatible with ectopic adrenocorticotropin hormone (ACTH) production. Computerized tomography (CT) showed a 3.6 cm thymic tumor which was successfully resected. Plasma ACTH (P-ACTH) normalized the first postoperative day. Histopathology demonstrated a well-differentiated neuroendocrine carcinoma with diffuse positivity for ACTH and focal corticotropin-releasing hormone (CRH) reactivity in a few scattered cells. The patient was in remission for 6 years. He then again presented with acute-onset Cushing's syndrome. Fluorine-labeled dihydroxyphenylalanine ((18)F-DOPA) PET/CT showed local uptake in the mediastinum and he underwent repeat resection. However, P-ACTH remained increased (613 ng/l) and 24-h urinary cortisol was 36,720 nmol, suggesting incomplete tumor removal or metastatic spread. Metyrapone treatment was initiated but then withdrawn because the patient spontaneously recovered and cortisol metabolism gradually normalized within 3 weeks. Histopathology demonstrated a recurrent neuroendocrine carcinoma with the same features as the previous lesion but this time CRH was strongly positive in more numerous cells. Normalization of P-ACTH after primary surgery was compatible with ectopic ACTH production. However, the delayed fall in P-ACTH and serum cortisol is compatible with ectopic CRH production and stimulation of pituitary ACTH secretion, which gradually resolved. Although ectopic CRH production is very rare, the unusual dynamics illustrated here should raise the possibility of CRH production by a neuroendocrine tumor. PMID:23233312

  10. Controlling access time to a high-fat diet during the inactive period protects against obesity in mice.

    PubMed

    Haraguchi, Atsushi; Aoki, Natsumi; Ohtsu, Teiji; Ikeda, Yuko; Tahara, Yu; Shibata, Shigenobu

    2014-10-01

    Free feeding (FF) with a high fat diet (HFD) causes excessive body weight gain, whereas restricted feeding (RF) with a HFD attenuates body weight gain. The effects of timing of feeding with a HFD (day vs. night) and feeding duration on energy homeostasis have not yet been investigated. In this study, we fed mice a HFD or a normal diet (ND) twice a day, during their active and inactive periods, on a schedule. The amount of food was regulated by feeding duration (2, 4 or 8 h). First, we investigated the effects of 4-h RF during active-inactive periods (ND-ND, HFD-HFD, ND-HFD or HFD-ND). Among all the 4-h RF groups, mice consumed almost the same amount of calories as those in the FF[ND] group, even those fed a HFD. Body weight and visceral fat in these three groups were lower than that in the FF[HFD] group. Second, we investigated the effects of RF duration. Body weight and visceral fat were higher in the 8-h groups than in the 4-h groups. Body weight and visceral fat were higher in the 2-h groups than in the 4-h groups even though the 2-h groups had less food. Third, we investigated the effects of eating a HFD during the inactive period, when RF duration was extended (2, 6 or 12 h). Mice were fed with a HFD during the inactive period for 2 h and fed with a ND during the active period for 2, 6 or 12 h. Body weight and visceral fat in these mice were comparable to those in the FF[ND] mice. The results of our first set of experiments suggest that 4-h RF was an adequate feeding duration to control the effect of a HFD on obesity. The results of our second set of experiments suggest 2-h RF (such as speed-eating) and 8-h RF, representative of eating disorders, are unhealthy feeding patterns related to obesity. The results of our third set of experiments suggest that eating a HFD for a short period during the night does not affect body weight and visceral fat. Taken together, these results indicate that consideration to feeding with a HFD during the inactive period and

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  12. Kinematic dynamo action in a sphere: Effects of periodic time-dependent flows on solutions with axial dipole symmetry

    NASA Astrophysics Data System (ADS)

    Willis, Ashley P.; Gubbins, David

    2004-06-01

    Choosing a simple class of flows, with characteristics that may be present in the Earth's core, we study the ability to generate a magnetic field when the flow is permitted to oscillate periodically in time. The flow characteristics are parameterised by D, representing a differential rotation, M, a meridional circulation, and C, a component characterising convective rolls. The dynamo action of all solutions with fixed parameters (steady flows) is known from earlier studies. Dynamo action is sensitive to these flow parameters and fails spectacularly for much of the parameter space where magnetic flux is concentrated into small regions, leading to high diffusion. In addition, steady flows generate only steady or regularly reversing oscillatory fields and cannot therefore reproduce irregular geomagnetic-type reversal behaviour. Oscillations of the flow are introduced by varying the flow parameters in time, defining a closed orbit in the space (D, M). When the frequency of the oscillation is small, the net growth rate of the magnetic field over one period approaches the average of the growth rates for steady flows along the orbit. At increased frequency time-dependence appears to smooth out flux concentrations, often enhancing dynamo action. Dynamo action can be impaired, however, when flux concentrations of opposite signs occur close together as smoothing destroys the flux by cancellation. It is possible to produce geomagnetic-type reversals by making the orbit stray into a region where the steady flows generate oscillatory fields. In this case, however, dynamo action was not found to be enhanced by the time-dependence. A novel approach is being taken to solve the time-dependent eigenvalue problem where, by combining Floquet theory with a matrix-free Krylov-subspace method, we can avoid large memory requirements for storing the matrix required by the standard approach.

  13. Prenatal Stress and Balance of the Child's Cardiac Autonomic Nervous System at Age 5-6 Years

    PubMed Central

    van Dijk, Aimée E.; van Eijsden, Manon; Stronks, Karien; Gemke, Reinoud J. B. J.; Vrijkotte, Tanja G. M.

    2012-01-01

    Objective Autonomic nervous system (ANS) misbalance is a potential causal factor in the development of cardiovascular disease. The ANS may be programmed during pregnancy due to various maternal factors. Our aim is to study maternal prenatal psychosocial stress as a potential disruptor of cardiac ANS balance in the child. Methods Mothers from a prospective birth cohort (ABCD study) filled out a questionnaire at gestational week 16 [IQR 12–20], that included validated instruments for state anxiety, depressive symptoms, pregnancy-related anxiety, parenting daily hassles and job strain. A cumulative stress score was also calculated (based on 80th percentiles). Indicators of cardiac ANS in the offspring at age 5–6 years are: pre-ejection period (PEP), heart rate (HR), respiratory sinus arrhythmia (RSA) and cardiac autonomic balance (CAB), measured with electrocardiography and impedance cardiography in resting supine and sitting positions. Results 2,624 mother-child pairs, only single births, were available for analysis. The stress scales were not significantly associated with HR, PEP, RSA and CAB (p≥0.17). Accumulation of maternal stress was also not associated with HR, PEP, RSA and CAB (p≥0.07). Conclusion Results did not support the hypothesis that prenatal maternal psychosocial stress deregulates cardiac ANS balance in the offspring, at least in rest, and at the age of five-six years. PMID:22272345

  14. Estimation of abbreviated mycophenolic acid area under the concentration-time curve during early posttransplant period by limited sampling strategy.

    PubMed

    Mohammadpour, A-H; Nazemian, F; Abtahi, B; Naghibi, M; Gholami, K; Rezaee, S; Nazari, M-R A; Rajabi, O

    2008-12-01

    Area under the concentration curve (AUC) of mycophenolic acid (MPA) could help to optimize therapeutic drug monitoring during the early post-renal transplant period. The aim of this study was to develop a limited sampling strategy to estimate an abbreviated MPA AUC within the first month after renal transplantation. In this study we selected 19 patients in the early posttransplant period with normal renal graft function (glomerular filtration rate > 70 mL/min). Plasma MPA concentrations were measured using reverse-phase high-performance liquid chromatography. MPA AUC(0-12h) was calculated using the linear trapezoidal rule. Multiple stepwise regression analysis was used to determine the minimal and convenient time points of MPA levels that could be used to derive model equations best fitted to MPA AUC(0-12h). The regression equation for AUC estimation that gave the best performance was AUC = 14.46 C(10) + 15.547 (r(2) = .882). The validation of the method was performed using the jackknife method. Mean prediction error of this model was not different from zero (P > .05) and had a high root mean square prediction error (8.06). In conclusion, this limited sampling strategy provided an effective approach for therapeutic drug monitoring during the early posttransplant period. PMID:19100462

  15. Elevated Mississippi River discharge during glacial times: A 6,000 year wet period on the North American continent

    NASA Astrophysics Data System (ADS)

    Hill, H. W.; Hollander, D. J.; Flower, B. P.; Quinn, T. M.

    2005-12-01

    Sedimentary basins proximal to major rivers can provide a coherent, high-resolution assessment of the oceanic and continental responses to changing hydrologic regimes attributed to abrupt climate variability. Documenting these regime changes under climatic extremes, including glacial time periods that are often considered cold and dry in temperate North America, is important to understand the potential impacts associated with changing hydrologic conditions. The Orca Basin in the northern Gulf of Mexico (GOM) is ideally situated to record inputs from the Mississippi River and to relate these inputs to changing moisture balance over North America. We use organic and inorganic geochemical analyses to document a 6 ka wet period on the North American continent from 32-38 ka, during glacial Marine Isotope Stage 3, that is decoupled from Laurentide Ice Sheet meltwater dynamics over this interval. This wet period is inferred from a 5-fold increase in the input of long-chain n-alkanes derived from terrestrial plants and concurrent increases in the percent coarse fraction and insoluble residue in the bulk sediment. Associated with the wet period, a 5-fold increase in the algal derived n-alkanes implies that continentally sourced nutrients supported marine production. A 0.6 ‰ increase in the inorganic δ13CG. ruber and a shift in the δ13C of bulk organic matter from -26 to -23 ‰ also points to an increase in marine production. Further, a 1°C cooling in SST, as determined from G.ruber Mg-derived temperatures, is synchronous with the fluvial inputs. Our evidence suggests that the GOM served as an enhanced moisture source to the Mississippi River basin during this interval, perhaps via the southern displacement of frontal weather systems, resulting in oceanic physical and biological changes. Results of this study will be discussed in the context of regionally defined climate patterns, continental paleorecords and global circulation models.

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

    ERIC Educational Resources Information Center

    Komrska, Shelley; Rupe, Melissa

    2005-01-01

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

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

    PubMed

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

    2012-03-01

    Most of the research related to human fatigue in the aviation industry has focussed on long-haul pilots, but short-haul pilots also experience elevated levels of fatigue. The aim of this study was to examine the impact of early start times on the amount of sleep obtained prior to duty and on fatigue levels at the start of duty. Seventy short-haul pilots collected data regarding their duty schedule and sleep/wake behaviour for at least two weeks. Data were collected using self-report duty/sleep diaries and wrist activity monitors. Mixed-effects regression analyses were used to examine the effects of duty start time (04:00-10:00 h) on (i) the total amount of sleep obtained in the 12h prior to the start of duty and (ii) self-rated fatigue level at the start of duty. Both analyses indicated significant main effects of duty start time. In particular, the amount of sleep obtained in the 12h prior to duty was lowest for duty periods that commenced between 04:00 and 05:00 h (i.e. 5.4h), and greatest for duty periods that commenced between 09:00 and 10:00 h (i.e. 6.6h). These data indicate that approximately 15 min of sleep is lost for every hour that the start of duty is advanced prior to 09:00 h. In addition, self-rated fatigue at the start of duty was highest for duty periods that commenced between 04:00 and 05:00 h, and lowest for duty periods that commenced between 09:00 and 10:00 h. Airlines should implement a fatigue risk management system (FRMS) for short-haul pilots required to work early-morning shifts. One component of the FRMS should be focussed on the production of 'fatigue-friendly' rosters. A second component of the FRMS should be focussed on training pilots to optimise sleep opportunities, to identify circumstances where the likelihood of fatigue is elevated, and to manage the risks associated with fatigue-related impairment. PMID:22239926

  18. Effects of the Family Bereavement Program on Academic Outcomes, Educational Expectations and Job Aspirations 6 Years Later: The Mediating Role of Parenting and Youth Mental Health Problems

    PubMed Central

    Schoenfelder, Erin N.; Tein, Jenn-Yun; Wolchik, Sharlene; Sandler, Irwin N.

    2014-01-01

    Experiencing the death of a parent during childhood is associated with a variety of difficulties, including lower academic achievement, that have implications for functioning in childhood and adulthood. This study examines effects of the Family Bereavement Program (FBP), a preventive intervention for parentally-bereaved youth and their caregivers, on grade point averages (GPA), educational expectations and job aspirations of youths 6 years after the intervention. A total of 244 bereaved youths ages 8-16 and their caregivers were randomized to either the FBP or a comparison group that received books about bereavement. Assessments occurred at pretest, post-test, and 11-month and 6-year follow-ups. Direct program effects on educational outcomes and job aspirations 6 years later were non-significant, although the program improved educational expectations for children with fewer behavior problems at program entry, and GPA for younger children. Mediational pathways for program effects on educational outcomes were also tested. Program-induced improvements in effective parenting at 11-month follow-up were associated with higher GPAs at 6-year follow-up for youth who were younger or for whom more time had passed since the loss. Program-induced improvements in parenting and teacher-rated youth mental health problems at the 6-year follow-up mediated program effects on youths’ educational expectations for those with fewer behavior problems at program entry. The implications of these findings for understanding processes related to academic and educational outcomes following the death of a parent and for prevention efforts to help bereaved and other high-risk children succeed in school are discussed. PMID:25052624

  19. Effects of the Family Bereavement Program on academic outcomes, educational expectations and job aspirations 6 years later: the mediating role of parenting and youth mental health problems.

    PubMed

    Schoenfelder, Erin N; Tein, Jenn-Yun; Wolchik, Sharlene; Sandler, Irwin N

    2015-02-01

    Experiencing the death of a parent during childhood is associated with a variety of difficulties, including lower academic achievement, that have implications for functioning in childhood and adulthood. This study examines effects of the Family Bereavement Program (FBP), a preventive intervention for parentally-bereaved youth and their caregivers, on grade point averages (GPA), educational expectations and job aspirations of youths 6 years after the intervention. A total of 244 bereaved youths ages 8-16 and their caregivers were randomized to either the FBP or a comparison group that received books about bereavement. Assessments occurred at pretest, post-test, and 11-month and 6-year follow-ups. Direct program effects on educational outcomes and job aspirations 6 years later were non-significant, although the program improved educational expectations for children with fewer behavior problems at program entry, and GPA for younger children. Mediational pathways for program effects on educational outcomes were also tested. Program-induced improvements in effective parenting at 11-month follow-up were associated with higher GPAs at 6-year follow-up for youth who were younger or for whom more time had passed since the loss. Program-induced improvements in parenting and teacher-rated youth mental health problems at the 6-year follow-up mediated program effects on youths' educational expectations for those with fewer behavior problems at program entry. The implications of these findings for understanding processes related to academic and educational outcomes following the death of a parent and for prevention efforts to help bereaved and other high-risk children succeed in school are discussed. PMID:25052624

  20. Performance of medical radiographic X-ray systems in Greece for the time period 1998-2004.

    PubMed

    Economides, S; Hourdakis, C J; Kalivas, N; Kalathaki, M; Simantirakis, G; Tritakis, P; Manousaridis, G; Vogiatzi, S; Kipouros, P; Boziari, A; Kamenopoulou, V

    2007-12-01

    This study presents the results of the on-site inspections performed by the Greek Atomic Energy Commission (GAEC) on conventional X-ray systems, both in public and private medical radiology departments. A part of the inspection concerns the assessment of important radiographic parameters obtained according to a specified quality control protocol and the comparison of the measured parameter values with the corresponding acceptance limits. A total number of 1011 radiographic systems were inspected by the GAEC during the period 1998-2004, with 63.4% of them being privately owned. Analysis of 8 different operational parameters is carried out providing information on the overall performance, as well as on each parameter of the inspected X-ray systems. Tube voltage reproducibility values show the highest percentage of acceptability (98.9%, 99.5% for private and public owned radiographic systems respectively), while linearity of radiation output for private systems (72.5%) and time accuracy for public ones (72.7%) show the worst results. The comparison of the results for the private sector to those of a similar study carried out during the period 1995-1997 indicates a substantial improvement in X-ray systems performance. Higher level of improvement shows exposure time accuracy (12.2% percentile increase) and linearity of radiation output (12.5% percentile increase). Nevertheless, the situation can be further optimized if maintenance and quality control of the radiographic systems are carried out on a more regular basis. PMID:18023226

  1. Occurrence of lymphoplasmacytic lymphoma 6 years after amelioration of primary cold agglutinin disease by rituximab therapy.

    PubMed

    Tanaka, Hiroaki; Hashimoto, Shinichiro; Sugita, Yasumasa; Sakai, Shio; Takeda, Yusuke; Abe, Daijiro; Takagi, Toshiyuki; Nakaseko, Chiaki

    2012-10-01

    Cold agglutinin disease (CAD) is a rare autoimmune hemolytic anemia, classified into primary and secondary types. Secondary CAD accompanies infection or malignant disease, most often lymphoma, whereas primary CAD frequently represents a lymphoproliferative bone marrow disorder characterized by clonal expansion of B cells. Here, I describe a case of lymphoplasmacytic lymphoma (LPL) developed 6 years after amelioration of primary CAD by rituximab monotherapy. A 54-year-old Japanese woman was diagnosed with primary CAD characterized by a small fraction of B lymphocytes and kappa laterality in the peripheral blood. M-protein was not detected by immuno-electrophoresis. The patient achieved remission following two courses of rituximab monotherapy. The level of IgM was specifically decreased, although levels of IgG and IgA were slightly increased. Six years after rituximab monotherapy, she developed LPL without CAD recurrence. Flow cytometry performed on bone marrow specimens revealed that lymphoma cells were positive for CD19 and CD20 with kappa laterality. The lymphoma may have transformed from clonal B lymphocytes at presentation of CAD. Rituximab monotherapy induced remission of CAD by specific decrease of IgM level, but did not eliminate the clonal B lymphocytes that may have progressed to LPL. This experience may provide clues toward the understanding of the pathophysiology of primary CAD with clonal lymphoproliferative disease of the bone marrow. PMID:22878940

  2. Helicobacter pylori infection with a duodenal ulcer in a 6-year-old boy.

    PubMed

    Hajikano, Miharu; Katsube, Yasuhiro; Takita, Yuko; Okada, Takuya; Asai, Makiko; Fujimatsu, Mariko; Nishizawa, Yoshiki; Kamisago, Mitsuhiro; Fujita, Takehisa; Shioya, Takeshi; Tokunaga, Akira

    2006-10-01

    A 6-year-old boy was hospitalized because of dark feces and facial pallor of 1 weeks duration. Other gastrointestinal symptoms, including vomiting and abdominal pain, were absent, but he felt dizziness when standing and fatigue on effort. Hematologic studies revealed iron-deficiency anemia, and endoscopy showed gastric erosions and a duodenal ulcer. All test results for Helicobacter pylori infection, including H. pylori antigen in stool, anti-H. pylori IgG immunoassay in serum, and the (13)C-urea breath test, were positive. Because an H. pylori-associated gastric ulcer had been diagnosed with endoscopy in the patients father 3 years earlier, father-son transmission was suspected. The patient was treated with triple-agent eradication therapy (proton pump inhibitor [lansoprazol], amoxicillin, and clarithromycin) for 2 weeks. One month after therapy was completed, eradication of H. pylori was confirmed by negative results on the stool antigen test. Peptic ulcer disease can occur in young children, as in this case. The stool antigen test kit is a useful and reliable method that can be used even in preschool children to diagnose H. pylori infection. PMID:17106182

  3. Duration of periventricular densities in preterm infants and neurological outcome at 6 years of age.

    PubMed Central

    Jongmans, M; Henderson, S; de Vries, L; Dubowitz, L

    1993-01-01

    Parenchymal echogenicities that break down into extensive cystic lesions are generally followed by severe motor deficit. However, the effect of echodensities in the periventricular white matter, so called 'flares', on later development is less well documented. The aim of the present study was to investigate the impact of neonatal flares in preterm infants on neurological status and motor competence at 6 years of age and to see to what extent outcome was related to duration of flares. Forty four children with flares, subdivided into three groups according to the duration of flares, and 62 children with normal scans were assessed on Touwen's neurological examination, the Movement ABC, and the British Ability Scales. No differences in cognitive abilities were found between the groups. The results of the motor assessments showed that performance decreased significantly with increasing duration of flares. In addition, there was a suggestion that this trend was stronger in measures assessing lower limb function than those of upper limb. Teachers were also able to identify differences between the groups of children on the basis of their motor performance in school. PMID:8346967

  4. [Caries prevention strategies for 6-year-olds. A randomized controlled study].

    PubMed

    Vermaire, J H; van Loveren, C

    2015-04-01

    A randomized controlled study of caries prevention strategies was conducted on patients with a mixed socioeconomic status in a large general dental practice in the Netherlands. A group of children following a non-operative caries treatment programme (NOCTP) was compared to a control group and a group that also received 2 topical fluoride applications (IPFA) as a supplement to the control programme (receiving a dental check-up twice a year with topical fluoride applications and routinely sealing of the first permanent molars). A total of 230 6-year-old children were randomly assigned to one of these groups. After 3 years, 179 children were studied again (54 NOCTP, 62 IPFA and 63 controls). Caries-increment was lowest in the NOCTP group (0.15 DMFS). In the IPFA group and the control group DMFS-increments were 0.34 and 0.47 respectively. Although the results of this study are very promising, a follow-up study on a larger scale is required to make clear whether the application of NOCTP is more effective than standard prevention in general practice. PMID:26210120

  5. Energy density and 6-year anthropometric changes in a middle-aged adult cohort.

    PubMed

    Vergnaud, Anne-Claire; Estaquio, Carla; Czernichow, Sébastien; Péneau, Sandrine; Hercberg, Serge; Galan, Pilar; Bertrais, Sandrine

    2009-07-01

    Dietary energy density (ED) may be a good predictor of weight gain because of its association with the regulation of appetite control signals. Among the participants of the 'SUpplementation en VItamines et Mineraux AntioXydants' prospective study, 2707 subjects were included in the present study. Changes in weight, waist circumference (WC), hip circumference (HC) and waist:hip ratio were calculated using measured data collected in 1995/1996 and 2001/2002. The mean changes in various anthropometric indicators according to baseline body-weight status (BMI < or > or = 25 kg/m2) and sex-specific tertiles of baseline ED level or 6-year changes in ED were compared by covariance analysis. In overweight subjects, weight gain was positively associated with high dietary ED at baseline (P for trend = 0.03) and with increasing ED during the follow-up (P for trend = 0.0008). Both the WC and HC changes were also positively related to baseline ED and change in ED in overweight subjects. However, the relationships observed for the WC and HC changes were no longer significant after adjustment for weight change. These results support the hypothesis of a deleterious effect of high-energy-dense diets on weight change for overweight subjects. This relationship could be mediated by physical activity level. Further research needs to be performed in other populations to determine whether ED could be effective strategies to prevent weight gain. PMID:19138440

  6. Inflamed molluscum contagiosum in a 6-year-old boy: a case report.

    PubMed

    Diaconu, Radu; Oprea, Bogdan; Vasilescu, Maria Mirela; Niculescu, Elena Carmen; Ciobanu, Mircea Ovidiu; Diaconu, Carmen; Gheonea, Cristian; Stănescu, Georgeta Ligia

    2015-01-01

    The precise prevalence of molluscum contagiosum (MC) is still unknown. The pediatric studies showed a cumulative incidence of 17% in children less than 15 years, but there are no studies available for Romania. The papular skin lesions are generally less than 5 mm, but the immunocompromised patients may develop large uncommon lesions. The pediatric cases are located mostly on the limbs, trunk or the face. The lab investigations are not usually required because the clinical features are typical. A biopsy followed by a light microscopy may help in some cases. We are presenting the case of a 6-year-old boy suffering from MC since almost a year. When examined in our clinic, the child developed 2 to 4 mm dome-shaped flesh-colored papules with central umbilication on his trunk diagnosed as MC. The microscopic examination revealed bud-like proliferation of the epidermis, molluscum bodies and moderate chronic inflammation of the dermis. In about one month of treatment, all the lesions disappeared without other local or general complications. PMID:26429183

  7. Cholestasis and protein-losing enteropathy secondary to hyperthyroidism in a 6-year-old girl.

    PubMed

    Gargouri, Lamia; Charfi, Manel; Maalej, Bayen; Majdoub, Imen; Safi, Faiza; Fourati, Hela; Hentati, Yosr; Daoud, Emna; Mnif, Zeineb; Abid, Mohamed; Mahfoudh, Abdelmajid

    2014-09-01

    Hepatic dysfunctions are not infrequent in patients with hyperthyroidism. These disorders may be related to the effects of the excess thyroid hormone secretion, to the uses of antithyroid drugs, or to the presence of concomitant hepatic diseases. Our aim is to describe the clinical and biochemical features of liver dysfunction related to thyrotoxicosis. We report here a case of a 6-year-old girl who was admitted for jaundice and pruritus as a result of the development of hyperthyroidism due to Graves' disease. On physical examination at admission, she was found to have jaundice and hepatomegaly. Laboratory data show cholestasis and protein-losing enteropathy. Investigations exclude other causes of hepatic disorder. One month after the initiation of antithyroid drug, the patient became euthyroid with improvement in jaundice and pruritus and normalization of hepatic tests and alpha antitrypsine clearance. In conclusion, the diagnosis of hyperthyroidism may be delayed in patients in whom the primary manifestations were pruritus and jaundice. The physician should suspect thyrotoxicosis prior to hepatitis or skin manifestations. PMID:24825088

  8. A New Explanation of Globular Cluster Color Bimodality: 6-year Results and Implications

    NASA Astrophysics Data System (ADS)

    Yoon, Suk-Jin

    2012-05-01

    The colors of globular clusters (GCs) in most large early-type galaxies are bimodal. This is generally taken as evidence for the presence of two GC subpopulations with different geneses, and thus forms a critical backbone of various galaxy formation theories. However, Yoon et al. (2006, Science 311, 1129) showed that the metallicity-color relations are highly inflected due to two complementary effects: (i) the integrated color of main-sequence and giant-branch is a mild nonlinear function of metallicity, and (ii) the rapid change in color due to the onset of the hot horizontal-branch further strengthens the non-linearity. Such nonlinear nature creates ''bimodal'' color distributions of old GCs from a broad underlying metallicity spread, even if it is unimodal. In this contribution, we summarize the 6-year results of theoretical and observational studies on the ''nonlinear color-metallicity relation'' scenario for the GC color bimodality and its implications on galaxy formation theories. We show that the hypothesis gives remarkably simple and cohesive explanations for all the key observations, including the close link of the GC color distributions to the host galaxy properties and the curious discrepancy in metallicity distribution functions between GC systems and their host galaxies’ constituent stars.

  9. Kerosene poisoning in childhood: a 6-year prospective study at the University of Ilorin Teaching Hospital.

    PubMed

    Fagbule, D O; Joiner, K T

    1992-01-01

    In a 6-year prospective study of kerosene poisoning in children admitted to the Department of Paediatrics, University of Ilorin Teaching Hospital (UITH), between January 1982 and December 1987, 109 cases were seen. They were aged 6 months to 9 years, with a male: female ratio of 1.8:1. Majority (79.8%) were below 2 years. Many households (52.3%) stored the agent in familiar beverage or household containers placed on kitchen or bedroom floors, within easy reach of infants and toddlers. Seventy-six (69.7%) cases had home remedies, palm oil being the most common accounting for 55.3%. More than half of the cases (56.9%) presented within 12 hours of the accident due to persistent cough and dyspnoea. Respiratory complications viz pneumonia, pleural effusion and pulmonary oedema were the most common, evident in 67.3% of those who had chest radiographs. Approximately, three quarters (74.3%) of patients with radiologic abnormalities had palm oil alone or in combination with milk as home remedies. Severity of poisoning was influenced by the type of home remedy and the interval between accident and admission (P less than 0.05; P less than 0.01 respectively). Presence of radiological or CNS abnormality or both was associated with a higher morbidity. The only death in the study had complications referable to both systems. Ways of minimizing the risk of kerosene poisoning and its attendant morbidity are discussed. PMID:1390371

  10. Grammatical outcomes of 3- & 6-year-old children who are hard of hearing

    PubMed Central

    Koehlinger, Keegan M.; Owen Van Horne, Amanda J; Moeller, Mary Pat

    2013-01-01

    Purpose Spoken language skills of 3- and 6-year-old children who are hard of hearing (HH) were compared to those of children with normal hearing (NH). Method Language skills were measured via MLU in words and percent correct use of finite verb morphology in obligatory contexts based on spontaneous conversational samples gathered from 185 children (145 HH; 40 NH). Aided speech intelligibility index (aided SII), better ear pure tone average (BE-PTA), maternal education, and age of amplification were used to predict outcomes within the HH group. Results On average, the HH group had MLUws that were .25-.5 words shorter than the NH group at both ages and they produced fewer obligatory verb morphemes. After age, aided SII and age of amplification predicted MLUw. Aided SII and PTA were not interchangeable in this analysis. Age followed by either PTA or aided SII best predicted verb morphology use. Conclusions Children who are HH lag behind their NH peers in grammatical aspects of language. Although some children appear to catch up, more than half the children who were HH fell below the 25th percentile. Continued monitoring of language outcomes is warranted since children who are HH are at increased risk for language learning difficulties. PMID:23882004

  11. [Cooperation among pharmaceutical, medical and nursing schools aimed at 6-year pharmaceutical education].

    PubMed

    Ono, Hideki; Kurono, Yukihisa

    2012-01-01

    Eleven universities which have pharmacy, medical or nursing school, have cooperated in an attempt to build the human and material systems for 6-year pharmacy education and to apply them to practical pharmacy educations. Members are Nagoya City University, Gifu Pharmaceutical University, University of Shizuoka, Aichi Gakuin University, Kinjo Gakuin University, Meijo University, Suzuka University of Medical Science, Hamamatsu University School of Medicine, Mie University, Aichi Medical University and Fujita Health University. Tokai Cooperation Center for Clinical Pharmacy Education, the steering committee and 5 subcommittees established following projects; 1) WEB-based system for supplementary lesson of natural science (for freshmen), 2) FD (Faculty Development) activity (for teachers), 3) WEB-based data-base system of disease case for PBL (Problem-based Learning) and methods for practice of physical assessment (for 4th grade students), 4) WEB-based system for practical pharmacy training (for 5th grade students), 5) Matching and WEB system for graduation practice at university hospital (for 6th grade students). PMID:22214575

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

    PubMed Central

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

    2006-01-01

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

  13. Hydraulic residence time and iron removal in a wetland receiving ferruginous mine water over a 4 year period from commissioning.

    PubMed

    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

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

    SciTech Connect

    Ambrose, David M.; Wilkening, Jon

    2008-12-11

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

  15. Dynamic RSA: Examining parasympathetic regulatory dynamics via vector-autoregressive modeling of time-varying RSA and heart period.

    PubMed

    Fisher, Aaron J; Reeves, Jonathan W; Chi, Cyrus

    2016-07-01

    Expanding on recently published methods, the current study presents an approach to estimating the dynamic, regulatory effect of the parasympathetic nervous system on heart period on a moment-to-moment basis. We estimated second-to-second variation in respiratory sinus arrhythmia (RSA) in order to estimate the contemporaneous and time-lagged relationships among RSA, interbeat interval (IBI), and respiration rate via vector autoregression. Moreover, we modeled these relationships at lags of 1 s to 10 s, in order to evaluate the optimal latency for estimating dynamic RSA effects. The IBI (t) on RSA (t-n) regression parameter was extracted from individual models as an operationalization of the regulatory effect of RSA on IBI-referred to as dynamic RSA (dRSA). Dynamic RSA positively correlated with standard averages of heart rate and negatively correlated with standard averages of RSA. We propose that dRSA reflects the active downregulation of heart period by the parasympathetic nervous system and thus represents a novel metric that provides incremental validity in the measurement of autonomic cardiac control-specifically, a method by which parasympathetic regulatory effects can be measured in process. PMID:27045609

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  17. Drift Compression and Final Focus for Intense Heavy Ion Beams with Non-periodic, Time-dependent Lattice

    SciTech Connect

    Hong Qin; Ronald C. Davidson; John J. Barnard; Edward P. Lee

    2005-02-14

    In the currently envisioned configurations for heavy ion fusion, it is necessary to longitudinally compress the beam bunches by a large factor after the acceleration phase. Because the space-charge force increases as the beam is compressed, the beam size in the transverse direction will increase in a periodic quadrupole lattice. If an active control of the beam size is desired, a larger focusing force is needed to confine the beam in the transverse direction, and a non-periodic quadrupole lattice along the beam path is necessary. In this paper, we describe the design of such a focusing lattice using the transverse envelope equations. A drift compression and final focus lattice should focus the entire beam pulse onto the same focal spot on the target. This is difficult with a fixed lattice, because different slices of the beam may have different perveance and emittance. Four time-dependent magnets are introduced in the upstream of drift compression to focus the entire pulse onto the sam e focal spot. Drift compression and final focusing schemes are developed for a typical heavy ion fusion driver and for the Integrated Beam Experiment (IBX) being designed by the Heavy Ion Fusion Virtual National Laboratory.

  18. Time-varying signal analysis to detect high-altitude periodic breathing in climbers ascending to extreme altitude.

    PubMed

    Garde, A; Giraldo, B F; Jané, R; Latshang, T D; Turk, A J; Hess, T; Bosch, M M; Barthelmes, D; Merz, T M; Hefti, J Pichler; Schoch, O D; Bloch, K E

    2015-08-01

    This work investigates the performance of cardiorespiratory analysis detecting periodic breathing (PB) in chest wall recordings in mountaineers climbing to extreme altitude. The breathing patterns of 34 mountaineers were monitored unobtrusively by inductance plethysmography, ECG and pulse oximetry using a portable recorder during climbs at altitudes between 4497 and 7546 m on Mt. Muztagh Ata. The minute ventilation (VE) and heart rate (HR) signals were studied, to identify visually scored PB, applying time-varying spectral, coherence and entropy analysis. In 411 climbing periods, 30-120 min in duration, high values of mean power (MP(VE)) and slope (MSlope(VE)) of the modulation frequency band of VE, accurately identified PB, with an area under the ROC curve of 88 and 89%, respectively. Prolonged stay at altitude was associated with an increase in PB. During PB episodes, higher peak power of ventilatory (MP(VE)) and cardiac (MP(LF)(HR) ) oscillations and cardiorespiratory coherence (MP(LF)(Coher)), but reduced ventilation entropy (SampEn(VE)), was observed. Therefore, the characterization of cardiorespiratory dynamics by the analysis of VE and HR signals accurately identifies PB and effects of altitude acclimatization, providing promising tools for investigating physiologic effects of environmental exposures and diseases. PMID:25820153

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

    SciTech Connect

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

    2012-04-10

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

  20. Detection of CMV DNA in the perilymph of a 6-year-old boy with congenital cytomegalovirus infection.

    PubMed

    Foulon, Ina; Soetens, Oriane; Vleurinck, Leen; Gordts, Frans; Leus, Astrid; Naessens, Anne

    2016-06-01

    We present the case of a 6-year-old boy who received a cochlear implant for profound sensorineural hearing loss after being born with cytomegalovirus (CMV) infection. Even after 6 years, CMV DNA was still found in the perilymph of the cochlea. Our case shows that CMV DNA can be present in the cochlea years after congenital CMV infection, and it can explain why progressive and/or late-onset hearing loss occurs in these children. PMID:27304443

  1. Fetal antiepileptic drug exposure: Adaptive and emotional/behavioral functioning at age 6years.

    PubMed

    Cohen, Morris J; Meador, Kimford J; Browning, Nancy; May, Ryan; Baker, Gus A; Clayton-Smith, Jill; Kalayjian, Laura A; Kanner, Andres; Liporace, Joyce D; Pennell, Page B; Privitera, Michael; Loring, David W

    2013-11-01

    The Neurodevelopmental Effects of Antiepileptic Drugs (NEAD) study is a prospective observational multicenter study in the USA and UK, which enrolled pregnant women with epilepsy on antiepileptic drug (AED) monotherapy from 1999 to 2004. The study aimed to determine if differential long-term neurodevelopmental effects exist across four commonly used AEDs (carbamazepine, lamotrigine, phenytoin, and valproate). In this report, we examine fetal AED exposure effects on adaptive and emotional/behavioral functioning at 6years of age in 195 children (including three sets of twins) whose parent (in most cases, the mother) completed at least one of the rating scales. Adjusted mean scores for the four AED groups were in the low average to average range for parent ratings of adaptive functioning on the Adaptive Behavior Assessment System-Second Edition (ABAS-II) and for parent and teacher ratings of emotional/behavioral functioning on the Behavior Assessment System for Children (BASC). However, children whose mothers took valproate during pregnancy had significantly lower General Adaptive Composite scores than the lamotrigine and phenytoin groups. Further, a significant dose-related performance decline in parental ratings of adaptive functioning was seen for both valproate and phenytoin. Children whose mothers took valproate were also rated by their parents as exhibiting significantly more atypical behaviors and inattention than those in the lamotrigine and phenytoin groups. Based upon BASC parent and teacher ratings of attention span and hyperactivity, children of mothers who took valproate during their pregnancy were at a significantly greater risk for a diagnosis of ADHD. The increased likelihood of difficulty with adaptive functioning and ADHD with fetal valproate exposure should be communicated to women with epilepsy who require antiepileptic medication. Finally, additional research is needed to confirm these findings in larger prospective study samples, examine

  2. Observing the Interstellar Medium Flow over the Past 6 Years with IBEX-Lo

    NASA Astrophysics Data System (ADS)

    Leonard, T.; Moebius, E.; Bzowski, M.; Fuselier, S.; Heirtzler, D.; Kubiak, M. A.; Kucharek, H.; Lee, M. A.; McComas, D. J.; Schwadron, N.; Wurz, P.

    2014-12-01

    The Interstellar Boundary Explorer (IBEX) has observed the interstellar neutral (ISN) gas flow over the past 6 years during the winter/spring when the Earth's motion opposes the ISN flow direction. Since IBEX observes near the perihelion of the interstellar atom trajectories, we are able to use an analytical model (Lee et al. 2012) based upon orbital mechanics to determine characteristics of the interstellar flow. The interstellar inflow latitude, velocity, and temperature are coupled to the inflow longitude and are restricted by the IBEX observations to a narrow valley in this parameter space (McComas et al. 2012). In our original analysis we found that the small spacecraft spin axis pointing out of the ecliptic plane had a significant influence on the determination of the ISN inflow vector (Möbius et al. 2012; Bzowski et al. 2012). Introducing the spacecraft spin axis tilt into the analytical model has shown that IBEX observations with various spin axis tilt orientations can help restrict the natural degeneracy of the ISN flow parameters as a function of inflow longitude. The IBEX operations team was able to successfully point the spin axis to be in the ecliptic during the 2012 and 2013 seasons and about 5 degrees below the ecliptic during the 2014 season. With this robust data set we are able to further test and develop the analytical model while producing a more comprehensive analysis of the ISN Flow parameters. We found that in its current implementation the analytical model describes the ISN flow most precisely for the spin axis orientation exactly in the ecliptic. This analysis refines the derived ISN flow parameters with a possible reconciliation between velocity vectors found with IBEX and Ulysses, but at a substantially higher temperature than previously reported.

  3. Gestational Weight Gain and Overweight in Children Aged 3–6 Years

    PubMed Central

    Guo, Lianhong; Liu, Jufen; Ye, Rongwei; Liu, Jianmeng; Zhuang, Zhixiong; Ren, Aiguo

    2015-01-01

    Objective To determine whether gestational weight gain (GWG) was associated with increased odds of childhood overweight after accounting for pre-pregnancy BMI. Methods In a prospective cohort study based on a premarital and perinatal health care system in China, data of 100 612 mother-child pairs were obtained. The main exposure was GWG as both a continuous and categorical variable. The outcome measure was overweight, defined by age- and sex-specific cutoff values for body mass index (BMI) in children aged 3–6 years. Results A 1-kg increase in maternal GWG was associated with an increase of 0.009 (95% confidence interval [CI]: 0.007–0.010, P < 0.001) in children’s mean BMI; in the subgroup of pre-pregnancy overweight/obese mothers, the increase in children’s BMI was 0.028 (95% CI, 0.017–0.039, P < 0.001). Excessive GWG played an important role in childhood overweight when adequate GWG was used as the reference, with an odds ratio (OR) of 1.21 (95% CI, 1.12–1.29). The risk was highest (OR 2.22; 95% CI, 1.79–2.76) in the children of mothers who were overweight/obese before pregnancy and gained excessive weight during pregnancy. Conclusions Greater maternal GWG was associated with greater offspring BMI, and the risk of overweight was doubled in children whose mothers were overweight/obese before pregnancy and gained excessive weight during pregnancy. As a result, maintenance of appropriate weight gain during pregnancy and prophylaxis of maternal overweight/obesity before pregnancy should be a strategy for preventing childhood overweight/obesity. PMID:26119288

  4. Body shape and size in 6-year old children: assessment by three-dimensional photonic scanning

    PubMed Central

    Santos, L P; Ong, K K; Day, F; Wells, J C K; Matijasevich, A; Santos, I S; Victora, C G; Barros, A J D

    2016-01-01

    Background: Body shape and size are typically described using measures such as body mass index (BMI) and waist circumference, which predict disease risks in adults. However, this approach may underestimate the true variability in childhood body shape and size. Objective: To use a comprehensive three-dimensional photonic scan approach to describe variation in childhood body shape and size. Subjects/Methods: At age 6 years, 3350 children from the population-based 2004 Pelotas birth cohort study were assessed by three-dimensional photonic scanner, traditional anthropometry and dual X-ray absorptiometry. Principal component analysis (PCA) was performed on height and 24 photonic scan variables (circumferences, lengths/widths, volumes and surface areas). Results: PCA identified four independent components of children's body shape and size, which we termed: Corpulence, Central:peripheral ratio, Height and arm lengths, and Shoulder diameter. Corpulence showed strong correlations with traditional anthropometric and body composition measures (r>0.90 with weight, BMI, waist circumference and fat mass; r>0.70 with height, lean mass and bone mass); in contrast, the other three components showed weak or moderate correlations with those measures (all r<0.45). There was no sex difference in Corpulence, but boys had higher Central:peripheral ratio, Height and arm lengths and Shoulder diameter values than girls. Furthermore, children with low birth weight had lower Corpulence and Height and arm lengths but higher Central:peripheral ratio and Shoulder diameter than other children. Children from high socio-economic position (SEP) families had higher Corpulence and Height and arm lengths than other children. Finally, white children had higher Corpulence and Central:peripheral ratio than mixed or black children. Conclusions: Comprehensive assessment by three-dimensional photonic scanning identified components of childhood body shape and size not captured by traditional anthropometry or

  5. Improved 6-year overall survival in AT/RT - results of the registry study Rhabdoid 2007.

    PubMed

    Bartelheim, Kerstin; Nemes, Karolina; Seeringer, Angela; Kerl, Kornelius; Buechner, Jochen; Boos, Joachim; Graf, Norbert; Dürken, Matthias; Gerss, Joachim; Hasselblatt, Martin; Kortmann, Rolf-Dieter; Teichert von Luettichau, Irene; Nagel, Inga; Nygaard, Randi; Oyen, Florian; Quiroga, Eduardo; Schlegel, Paul-Gerhardt; Schmid, Irene; Schneppenheim, Reinhard; Siebert, Reiner; Solano-Paez, Palma; Timmermann, Beate; Warmuth-Metz, Monika; Frühwald, Michael Christoph

    2016-08-01

    Atypical teratoid rhabdoid tumors (AT/RT) are characterized by mutations and subsequent inactivation of SMARCB1 (INI1, hSNF5), a predilection for very young children and an unfavorable outcome. The European Registry for rhabdoid tumors (EU-RHAB) was established to generate a common European database and to establish a standardized treatment regimen as the basis for phase I/II trials. Thus, genetic analyses, neuropathologic and radiologic diagnoses, and a consensus treatment regimen were prospectively evaluated. From 2005 to 2009, 31 patients with AT/RT from four countries were recruited into the registry study Rhabdoid 2007 and treated with systemic and intraventricular chemotherapy. Eight patients received high-dose chemotherapy, 23 radiotherapy, and 17 maintenance therapy. Reference evaluations were performed in 64% (genetic analyses, FISH, MLPA, sequencing) up to 97% (neuropathology, INI1 stain). Germ-line mutations (GLM) were detected in 6/21 patients. Prolonged overall survival was associated with age above 3 years, radiotherapy and achievement of a complete remission. 6-year overall and event-free survival rates were 46% (±0.10) and 45% (±0.09), respectively. Serious adverse events and one treatment-related death due to insufficiency of a ventriculo peritoneal shunt (VP-shunt) and consecutive herniation were noted. Acquisition of standardized data including reference diagnosis and a standard treatment schedule improved data quality along with a survival benefit. Treatment was feasible with significant but manageable toxicity. Although our analysis is biased due to heterogeneous adherence to therapy, EU-RHAB provides the best available basis for phase I/II clinical trials. PMID:27228363

  6. Impulse oscillometry and respiratory symptoms in World Trade Center responders, 6 years post-9/11.

    PubMed

    Mauer, Matthew P; Cummings, Karen R

    2010-04-01

    This study evaluated whether impulse oscillometry (IOS) testing revealed signs of respiratory disease in New York State (NYS) World Trade Center (WTC) responders in comparison with unexposed NYS employees. It also compared self-reported respiratory symptoms between the two groups, 6 years post-9/11. For this evaluation participants completed a self-administered questionnaire regarding respiratory symptoms. IOS testing included measures of resistance and reactance to assess for peripheral versus central airway effects. Two hundred forty-eight subjects (99 exposed and 149 unexposed) were included in the final analysis. Since September 11, 2001, NYS responders were more likely to report new or worsening cough in the absence of a respiratory infection, cough consistent with chronic bronchitis, current respiratory symptoms, or lower respiratory symptoms in the last 12 months. Significant associations were found between IOS indices and gender, smoking history, and obesity. When comparing exposed and unexposed participants, there were no significant differences in the geometric means of the IOS indices. Responders who used a respirator with canister demonstrated significantly lower respiratory resistance at 5 and 20 Hz (R5 and R20). While this study has provided no evidence of an association between WTC exposure and peripheral airways disease in this cohort of responders, results do suggest that use of a respirator with canister may be protective for central airways in responders exposed to dust and smoke. This emphasizes the importance of stressing proper respirator use in planning responses to future disasters. Our control data also provide useful reference values for future IOS research. PMID:20012641

  7. A 6 year Geohelminth infection profile of children at high altitude in Western Nepal

    PubMed Central

    Mukhopadhyay, Chiranjay; Wilson, Godwin; Chawla, Kiran; VS, Binu; Shivananda, PG

    2008-01-01

    Background Geohelminth infections are a major problem of children from the developing countries. Children with these infections suffer from developmental impairments and other serious illnesses. This study aimed to measure the prevalence of geohelminth infection, infection intensity as well as the change in the intensity in children from Western Nepal over years. Methods This 6-year hospital based prospective study at the Manipal Teaching Hospital, Pokhara included children (< 15 years) visiting the hospital from Kaski and 7 surrounding districts. Samples were also collected from children in the community from different medical camps. Three stool samples from every child were processed using direct and concentration methods. The Kato-Katz technique was used for measuring the intensity of infection. Results The overall prevalence in hospital - attending children was 9.2% with 7.6% in preschool (0 – 5 y) and 11.0% in school-age (6 – 15 y) children, and in community 17.7% with 14.8% in pre-school and 20.5% in school-age children. Ascaris lumbricoides, Trichuris trichiura, Ancylostoma deodenale and Strongyloides stercoralis were the common geohelminths with a gradual decrease in worm load over the years. School-age children were found to be significantly more prone to geohelminth infection as compared to preschool children, but no statistical difference was detected by gender, district as well as season. Conclusion This heavy infection of geohelminths in children should be corrected by appropriate medication and maintaining strict personal hygiene. Health education, clean water, good sewage management and a congenial environment should be ensured to minimise infection. PMID:18366807

  8. Vitamin D Intake and Status in 6-Year-Old Icelandic Children Followed up from Infancy

    PubMed Central

    Thorisdottir, Birna; Gunnarsdottir, Ingibjorg; Steingrimsdottir, Laufey; Palsson, Gestur I.; Birgisdottir, Bryndis E.; Thorsdottir, Inga

    2016-01-01

    High serum 25-hydroxyvitamin D (25(OH)D) levels have been observed in infants in Nordic countries, likely due to vitamin D supplement use. Internationally, little is known about tracking vitamin D status from infancy to childhood. Following up 1-year-old infants in our national longitudinal cohort, our aims were to study vitamin D intake and status in healthy 6-year-old Icelandic children (n = 139) and to track vitamin D status from one year of age. At six years, the mean 25(OH)D level was 56.5 nmol/L (SD 17.9) and 64% of children were vitamin D sufficient (25(OH)D ≥ 50 nmol/L). A logistic regression model adjusted for gender and breastfeeding showed that higher total vitamin D intake (Odds ratio (OR) = 1.27, 95% confidence interval (CI) = 1.08–1.49), blood samples collected in summer (OR = 8.88, 95% CI = 1.83–43.23) or autumn (OR = 5.64, 95% CI = 1.16–27.32) compared to winter/spring, and 25(OH)D at age one (OR = 1.02, 95% CI = 1.002–1.04) were independently associated with vitamin D sufficiency at age six. The correlation between 25(OH)D at age one and six was 0.34 (p = 0.003). Our findings suggest that vitamin D status in infancy, current vitamin D intake and season are predictors of vitamin D status in early school age children. Our finding of vitamin D status tracking from infancy to childhood provides motivation for further studies on tracking and its clinical significance. PMID:26861385

  9. Vitamin D Intake and Status in 6-Year-Old Icelandic Children Followed up from Infancy.

    PubMed

    Thorisdottir, Birna; Gunnarsdottir, Ingibjorg; Steingrimsdottir, Laufey; Palsson, Gestur I; Birgisdottir, Bryndis E; Thorsdottir, Inga

    2016-02-01

    High serum 25-hydroxyvitamin D (25(OH)D) levels have been observed in infants in Nordic countries, likely due to vitamin D supplement use. Internationally, little is known about tracking vitamin D status from infancy to childhood. Following up 1-year-old infants in our national longitudinal cohort, our aims were to study vitamin D intake and status in healthy 6-year-old Icelandic children (n = 139) and to track vitamin D status from one year of age. At six years, the mean 25(OH)D level was 56.5 nmol/L (SD 17.9) and 64% of children were vitamin D sufficient (25(OH)D ≥ 50 nmol/L). A logistic regression model adjusted for gender and breastfeeding showed that higher total vitamin D intake (Odds ratio (OR) = 1.27, 95% confidence interval (CI) = 1.08-1.49), blood samples collected in summer (OR = 8.88, 95% CI = 1.83-43.23) or autumn (OR = 5.64, 95% CI = 1.16-27.32) compared to winter/spring, and 25(OH)D at age one (OR = 1.02, 95% CI = 1.002-1.04) were independently associated with vitamin D sufficiency at age six. The correlation between 25(OH)D at age one and six was 0.34 (p = 0.003). Our findings suggest that vitamin D status in infancy, current vitamin D intake and season are predictors of vitamin D status in early school age children. Our finding of vitamin D status tracking from infancy to childhood provides motivation for further studies on tracking and its clinical significance. PMID:26861385

  10. IQ at 6 years after in utero exposure to antiepileptic drugs

    PubMed Central

    Baker, Gus A.; Briggs, Maria; Cheyne, Christopher P.; Cohen, Morris J.; García-Fiñana, Marta; Gummery, Alison; Kneen, Rachel; Loring, David W.; Mawer, George; Meador, Kimford J.; Shallcross, Rebekah; Clayton-Smith, Jill

    2015-01-01

    Objective: To delineate the risk to child IQ associated with frequently prescribed antiepileptic drugs. Methods: Children born to women with epilepsy (n = 243) and women without epilepsy (n = 287) were recruited during pregnancy and followed prospectively. Of these, 408 were blindly assessed at 6 years of age. Maternal and child demographics were collected and entered into statistical models. Results: The adjusted mean IQ was 9.7 points lower (95% confidence interval [CI] −4.9 to −14.6; p < 0.001) for children exposed to high-dose (>800 mg daily) valproate, with a similar significant effect observed for the verbal, nonverbal, and spatial subscales. Children exposed to high-dose valproate had an 8-fold increased need of educational intervention relative to control children (adjusted relative risk, 95% CI 8.0, 2.5–19.7; p < 0.001). Valproate at doses <800 mg daily was not associated with reduced IQ, but was associated with impaired verbal abilities (−5.6, 95% CI −11.1 to −0.1; p = 0.04) and a 6-fold increase in educational intervention (95% CI 1.4–18.0; p = 0.01). In utero exposure to carbamazepine or lamotrigine did not have a significant effect on IQ, but carbamazepine was associated with reduced verbal abilities (−4.2, 95% CI −0.6 to −7.8; p = 0.02) and increased frequency of IQ <85. Conclusions: Consistent with data from younger cohorts, school-aged children exposed to valproate at maternal doses more than 800 mg daily continue to experience significantly poorer cognitive development than control children or children exposed to lamotrigine and carbamazepine. PMID:25540307

  11. Evaluation of Wrf Real-Time Forecast during MC3E Period: Sensitivity of Model Configuration for Diurnal Precipitation Variation

    NASA Astrophysics Data System (ADS)

    Wu, D.; Matsui, T.; Tao, W.; Peters-Lidard, C. D.; Rienecker, M. M.; Hou, A. Y.

    2011-12-01

    The WRF-ARW model with high resolution was employed for the real-time forecast during the MC3E field campaign period (April 22 - June 6, 2011) over the SGP region. The model features new Goddard microphysics (Lang et al. 2011) and Goddard radiation schemes, and runs twice a day with 00Z and 12Z forecast cycle. Our primary goal is to examine the model's ability to simulate diurnal variation of precipitation and to identify physical processes that are essential for improving the forecast skills. The studies consisted with the comparisons among a composite of the WRF simulations during the campaign period with NLDAS (North-American Land Data Assimilation Systems) and NAM (North America Mesoscale Model) forecast. A set of the WRF simulations with different physics parameterization schemes and with different horizontal resolutions are also conducted to investigate effects of the model resolution and physics schemes on the propagating rainfall system over the SGP site. Results showed that the WRF simulation with fine (2km of grid spacing) and intermediate (6 ~ 10km of grid spacing) resolution with parameterized convective schemes could reproduce reasonable MCS propagation, thus diurnal rainfall cycles over the SGP site. However, even if using the same convective parameterization, with the coarse-resolution (18~30km of grid spacing) configuration, the WRF simulation do not capture the MCS propagation reasonably. This means that model effective resolution (10 times of grid spacing) needs to be less than 100km (i.e., 10km of grid spacing), which is close to the typical Rossby Radius of deformation in the Mid-latitude summertime disturbance (100~150km distance). In addition, hail option in the Goddard microphysics appears to be an effective option to reproduce a more realistic continental MCS structure in the WRF simulations.

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  13. Longitudinal analysis of ear infection and hearing impairment: findings from 6-year prospective cohorts of Australian children

    PubMed Central

    2013-01-01

    Background Middle ear infection is common in childhood. Despite its prevalence, there is little longitudinal evidence about the impact of ear infection, particularly its association to hearing loss. By using 6-year prospective data, we investigate the onset and impact over time of ear infection in Australian children. Methods We analyse 4 waves of the Longitudinal Study of Australian Children (LSAC) survey collected in 2004, 2006, 2008, and 2010. There are two age cohorts in this study (B cohort aged 0/1 to 6/7 years N=4242 and K cohort aged 4/5 to 10/11 years N=4169). Exposure was parent-reported ear infection and outcome was parent-reported hearing problems. We modelled ear infection onset and subsequent impact on hearing using multivariate logistic regressions, reporting Adjusted Odds Ratios (AOR) and Confidence Intervals (95% CI). Separate analyses were reported for indigenous and non-indigenous children. Results Associations of ear infections between waves were found to be very strong both among both indigenous and non-indigenous children in the two cohorts. Reported ear infections at earlier wave were also associated with hearing problems in subsequent wave. For example, reported ear infections at age 4/5 years among the K cohort were found to be predictors of hearing problems at age 8/9 years (AOR 4.0, 95% CI 2.2-7.3 among non-indigenous children and AOR 7.7 95% CI 1.0-59.4 among indigenous children). Number of repeated ear infections during the 6-year follow-up revealed strong dose–response relationships with subsequent hearing problems among non-indigenous children (AORs ranged from 4.4 to 31.7 in the B cohort and 4.4 to 51.0 in the K cohort) but not statistically significant among indigenous children partly due to small sample. Conclusions This study revealed the longitudinal impact of ear infections on hearing problems in both indigenous and non-indigenous children. These findings highlight the need for special attention and follow-up on children

  14. Kinematic Comparison of Pediatric Human Volunteers and the Hybrid III 6-Year-Old Anthropomorphic Test Device

    PubMed Central

    Seacrist, Thomas; Balasubramanian, Sriram; García-España, J. Felipe; Maltese, Matthew R.; Arbogast, Kristy B.; Lopez-Valdes, Francisco J.; Kent, Richard W.; Tanji, Hiromasa; Higuchi, Kazuo

    2010-01-01

    The Hybrid III 6-year-old ATD has been benchmarked against adult-scaled component level tests but the lack of biomechanical data hinders the effectiveness of the procedures used to scale the adult data to the child. Whole body kinematic validation of the pediatric ATD through limited comparison to post mortem human subjects (PMHS) of similar age and size has revealed key differences attributed to the rigidity of the thoracic spine. As restraint systems continue to advance, they may become more effective at limiting peak loads applied to occupants, leading to lower impact environments for which the biofidelity of the ATD is not well established. Consequently, there is a growing need to further enhance the assessment of the pediatric ATD by evaluating its biofidelity at lower crash speeds. To this end, this study compared the kinematic response of the Hybrid III 6 year old ATD against size-matched male pediatric volunteers (PVs) (6–9 yrs) in low-speed frontal sled tests. A 3-D near-infrared target tracking system quantified the position of markers at seven locations on the ATD and PVs (head top, opisthocranion, nasion, external auditory meatus, C4, T1, and pelvis). Angular velocity of the head, seat belt forces, and reaction forces on the seat pan and foot rest were also measured. The ATD exhibited significantly greater shoulder and lap belt, foot rest, and seat pan normal reaction loads compared to the PVs. Contrarily, PVs exhibited significantly greater seat pan shear. The ATD experienced significantly greater head angular velocity (11.4 ± 1.7 rad/s vs. 8.1 ± 1.4 rad/s), resulting in a quicker time to maximum head rotation (280.4 ± 2.5 ms vs 334.2 ± 21.7 ms). The ATD exhibited significantly less forward excursions of the nasion (171.7 ± 7.8 mm vs. 199.5 ± 12.3 mm), external auditory meatus (194.5 ± 11.8 mm vs. 205.7 ± 10.3 mm), C4 (127.0 ± 5.2 mm vs. 183.3 ± 12.8 mm) and T1 (111.1 ± 6.5 mm vs. 153.8 ± 10.5 mm) compared to the PVs. These analyses

  15. Inflexible parents, inflexible kids: a 6-year longitudinal study of parenting style and the development of psychological flexibility in adolescents.

    PubMed

    Williams, Kathryn E; Ciarrochi, Joseph; Heaven, Patrick C L

    2012-08-01

    Parenting behaviors have been linked to children's self regulation, but it is less clear how they relate to adolescent psychological flexibility. Psychological flexibility is a broad construct that describes an individual's ability to respond appropriately to environmental demands and internal experiences in the service of their goals. We examined the longitudinal relationships between perceived parenting style and psychological flexibility among students at five Australian schools (N= 749) over 6 years, beginning in Grade 7 (50.3% female, mean age 12.39 years). Parenting style was measured in Grades 7 and 12, and psychological flexibility from Grade 9 through 12. Psychological flexibility decreased, on average, with age. Multi-level modelling indicated that authoritarian parenting (low warmth, high control) in Grade 7 predicted later (low) psychological flexibility. Moreover, increases in authoritarian parenting and decreases in authoritative parenting (high warmth and control) were associated with adolescent psychological flexibility across the high school years. Change in parenting predicted future psychological flexibility but did not predict change over time. Structural Equation Modelling revealed that adolescent psychological flexibility in Grade 9 predicted later decreases in authoritarian and increases in authoritative parenting. We discuss the implications of these findings for understanding how parenting changes and the consequences of such change for the development of psychological flexibility. PMID:22311519

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  17. Time variations of the total electron content in the Southeast Asian equatorial ionization anomaly for the period 2006-2011

    NASA Astrophysics Data System (ADS)

    Le Huy, M.; Amory-Mazaudier, C.; Fleury, R.; Bourdillon, A.; Lassudrie-Duchesne, P.; Tran Thi, L.; Nguyen Chien, T.; Nguyen Ha, T.; Vila, P.

    2014-08-01

    This study presents the time variations of the total electron content in the South East Asian equatorial ionization anomaly. The time variation of the TEC is analyzed through the period 2006-2011 by using a latitudinal chain of GPS stations extending in the northern and southern hemisphere. The data shows that the shape of the diurnal variation of the TEC depends on the latitude: a plateau is observed at the stations near the equator and a Gaussian at the station distant from the equator. We observe a semiannual pattern in all the stations with maxima at equinox. In both hemispheres, the amplitude of the crest is larger in spring than autumn from 2006 to 2008 and smaller in spring than in autumn from 2009 to 2011. We also observe an asymmetry between the amplitude and the position of the two crests of ionization. There is a very high level of correlation between the amplitude of the TEC at the two crests and the sunspot number: ∼0.88. During the deep solar minimum 2008-2009, the amplitude of crests of ionization becomes small during several months in summer and winter. The results show that both crests move significantly equatorward in winter than other seasons and there is a tendency for both crests to appear earlier in winter and later in summer.

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  19. Network-Level Connectivity Dynamics of Movie Watching in 6-Year-Old Children

    PubMed Central

    Emerson, Robert W.; Short, Sarah J.; Lin, Weili; Gilmore, John H.; Gao, Wei

    2015-01-01

    Better understanding of the developing brain’s functional mechanisms is critical for improving diagnosis and treatment of different developmental disorders. Particularly, characterizing how the developing brain dynamically reorganizes during different cognitive states may offer novel insight into the neuronal mechanisms of cognitive deficits. Imaging the brain during naturalistic conditions, like movie watching, provides a highly practical way to study young children’s developing functional brain systems. In this study we compared the network-level functional organization of 6-year-old children while they were at rest with their functional connectivity as they watched short video clips. We employed both a data-driven independent component analysis (ICA) approach and a hypothesis-driven seed-based analysis to identify changes in network-level functional interactions during the shift from resting to video watching. Our ICA results showed that naturally watching a movie elicits significant changes in the functional connectivity between the visual system and the dorsal attention network when compared to rest (t(32) = 5.02, p = 0.0001). More interestingly, children showed an immature, but qualitatively adult-like, pattern of reorganization among three of the brain’s higher-order networks (frontal control, default-mode and dorsal attention). For both ICA and seed-based approaches, we observed a decrease in the frontal network’s correlation with the dorsal attention network (ICA: t(32) = −2.46, p = 0.02; Seed-based: t(32) = −1.62, p =0.12) and an increase in its connectivity with the default mode network (ICA: t(32) = 2.84, p = 0.008; Seed-based: t(32) = 2.28, p =0.03), which is highly consistent with the pattern observed in adults. These results offer improved understanding of the developing brain’s dynamic network-level interaction patterns during the transition between different brain states and call for further studies to examine potential alterations to

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

    NASA Astrophysics Data System (ADS)

    Wang, Gang; Ni, Wei-Tou

    2015-05-01

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