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Sample records for 6-year time period

  1. Geodetic Constraints on Mantle Q at Periods from a Fortnight to 18.6 Years

    NASA Astrophysics Data System (ADS)

    Benjamin, D.; Wahr, J.; Desai, S.

    2002-12-01

    Seismic observations have provided numerous constraints on the earth's spherically-averaged mantle anelasticity at periods of tens of minutes and shorter. Meanwhile, post-glacial rebound and other geodynamic studies provide information at periods of a few thousand years and longer. However, constraints at intermediate periods are scarce. Such constraints could be useful in trying to connect the seismic anelastic models with the longer-period visco-elastic behavior. Here we will describe constraints on anelasticity in this intermediate range of periods as obtained from earth tide and earth rotation observations. We discuss results from: (1) VLBI observations of the monthly and fortnightly tidal variations in rotation rate; (2) satellite laser ranging observations of the 18.6-year tidal variations in the earth's gravitational field; and (3) astrometric and geodetic observations of the 14-month Chandler Wobble period and damping. We find that these observations are consistent with a nearly frequency-independent mantle Q stretching from seismic periods all the way out to the 14-month Chandler Wobble period; but that Q appears to decrease significantly between 14-months and 18.6-years.

  2. 6-year periodicity and variable synchronicity in a mass-flowering plant.

    PubMed

    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.

  3. 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

  4. Depressive symptom trajectories over a 6-year period following myocardial infarction: predictive function of cognitive appraisal and coping.

    PubMed

    Kroemeke, Aleksandra

    2016-04-01

    The association between distinct patterns of depression and coping variables in myocardial infarction (MI) survivors over the long-term is unclear. The study aims to evaluate depressive trajectories and their covariates, including coping and cognitive appraisal, following MI over a period of 6 years. Depressive symptoms were assessed in 200 patients a few days after the first MI, and 1 month, 6 months and 6 years later. Cognitive appraisal and coping were assessed during the first three time points. Three latent depressive trajectories were identified: chronic (high; increasing then decreasing; n = 49), rising (moderate; decreasing then increasing; n = 121) and low (low; decreasing then stabilizing; n = 30). The chronic trajectory was associated with higher negative appraisal and emotion-focused coping. The findings clarify the long-term longitudinal trajectories of post-MI depressive symptoms and their association with coping variables, revealing the unfavorable impact of negative cognition and palliative coping.

  5. 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

  6. Periodic 18.6-year and cyclic 11-year induced drought and flood in northeastern China and some global implications

    NASA Astrophysics Data System (ADS)

    Currie, Robert Guinn; Fairbridge, Rhodes W.

    The general patterns of climatic evolution in China during the Holocene are reviewed, and following the postglacial eustatic rise of sea-level and the institution of the East Asian Monsoon, the systems and principal fluctuations are found to be concordant with those operating elsewhere in the globe. China's unique wealth of written history provides an abundance of proxy data on the climatic record and that record now furnishes a basis for analysing both long-term and short-term fluctuations, as well as sunspot behavior, that together provide an insight into extraterrestrial forcing. Recent Chinese work suggests a solar forcing, but our own studies suggest rather that a lunar tidal component, reinforced at times by the solar element may prove more important. Analysis of a drought-flood index for Peking (Beijing) in northeastern China since A.D. 1470 supports evidence (Hameed et al., 1983) for both periodic lunar nodal 18.6-year and solar cyclic 11-year induced drought-flood in the region. The nodal term exhibits bistable phasing with respect to epochs of tidal maxima (for our century epochs occurred at 1917.5, 1936.1, 1954.7 and 1973.3), a phenomenon previously found in drought-flood proxy data for South America (Currie, 1983), India (Currie, 1984a), North America (Currie, 1984d), and Africa (Hameed and Currie, 1985; Currie and Hameed, 1985). Solar cycle epochs of drought-flood are tabulated for the past two centuries, and compared with those from North America and Africa.

  7. Remote impacts of the 18.6 year period modulation of localized tidal mixing in the North Pacific

    NASA Astrophysics Data System (ADS)

    Osafune, S.; Yasuda, I.

    2013-06-01

    The impact of the 18.6 year period modulation of the localized strong tidal mixing on the annual mean sea surface temperature (SST) in the open North Pacific Ocean is analyzed in a numerical experiment using an ocean general circulation model. Oscillatory SST anomalies induced in this model move eastward along the boundary between the subarctic and the subtropical gyres from the western boundary to the central Pacific in about 10 years, with a speed slower than that of the surface currents. Anomalous currents in the upper 300 m play an important role in inducing SST anomalies. These anomalous currents are coupled to subsurface density anomalies and could be related to eastward moving, low-mode (second or higher), baroclinic long Rossby waves. These results suggest that the 18.6 year modulation of localized strong tidal mixing can influence large-scale SST and/or heat flux, and thus climate, as a result of remote impacts associated with changes in the mid-depth density structure, induced locally where mixing is strong, that move horizontally into the open ocean.

  8. Bidecadal variability in the Bering Sea and the relation with 18.6 year period nodal tidal cycle

    NASA Astrophysics Data System (ADS)

    Osafune, S.; Yasuda, I.

    2010-02-01

    Bidecadal variations are investigated in the Bering Sea, especially in the southeastern basin adjacent to the Aleutian passes, where vertical mixing may be strong because of the diurnal tide. Those variations found in this region are synchronized with the 18.6 year period nodal tidal cycle, and the temporal patterns are similar to ones around the northwestern subarctic Pacific near the Kuril Straits reported by a previous study. Salinity and density in the upper layer are high in the periods when the diurnal tide is strong. In the intermediate layer, layer thickness is large, and isopycnal potential temperature and apparent oxygen utilization are low in the same periods. It is shown that these variations are consistent with the patterns expected from the nodal modulation of vertical mixing, and a simple two-dimensional model, assuming a balance between anomalous vertical mixing and advection of anomaly by the mean current, succeeds to some extent in explaining the variations of the upper layer salinity and isopycnal temperature and apparent oxygen utilization in the intermediate layer.

  9. Periodic (18.6-year) and cyclic (11-year) induced drought and flood in western North America

    NASA Astrophysics Data System (ADS)

    Currie, Robert Guinn

    1984-08-01

    Analysis of 102 reent tree-ring chronologies confirms earlier evidence for 18.6-year tidal drought/flood induction (Currie, 1981d, 1984b) and led to discovery of 11-year solar cycle induced drought/flood for western North America. Bistable phasing in terms of geography is found with epohs of maximum in lunar nodal 18.6-year drought in western Canada out of phase with those in the western United States and northern Mexico the past two centuries. Solar drought/flood induction provides one mechanism that appears to have modulated the intensity of nodal drought/flood induction in the latter region, most recently at epoch 1936.1. The above results were confirmed by analysis of yet more voluminous data, and they le to discovery of an example of bistable phasing with respect to time in western Canada during the 17th century. The implications for agriculture of such phenomena, which occur worldwide (Currie, 1984c), are surveyed.

  10. The 18.6-year period moon-tidal cycle in Pacific Decadal Oscillation reconstructed from tree-rings in western North America

    NASA Astrophysics Data System (ADS)

    Yasuda, Ichiro

    2009-03-01

    Time-series of Pacific Decadal Oscillation (PDO) reconstructed from tree-rings in Western North America is found to have a statistically significant periodicity of 18.6-year period lunar nodal tidal cycle; negative (positive) PDO tends to occur in the period of strong (weak) diurnal tide. In the 3rd and 5th (10th, 11th and 13rd) year after the maximum diurnal tide, mean-PDO takes significant negative (positive) value, suggesting that the Aleutian Low is weak (strong), western-central North Pacific in 30-50°N is warm (cool) and equator-eastern rim of the Pacific is cool (warm). This contributes to climate predictability with a time-table from the astronomical tidal cycle.

  11. Validation of activPAL defined sedentary time and breaks in sedentary time in 4- to 6-year-olds.

    PubMed

    Janssen, Xanne; Cliff, Dylan P; Reilly, John J; Hinkley, Trina; Jones, Rachel A; Batterham, Marijka; Ekelund, Ulf; Brage, Soren; Okely, Anthony D

    2014-02-01

    This study examined the classification accuracy of the activPAL, including total time spent sedentary and total number of breaks in sedentary behavior (SB) in 4- to 6-year-old children. Forty children aged 4-6 years (5.3 ± 1.0 years) completed a ~150-min laboratory protocol involving sedentary, light, and moderate- to vigorous-intensity activities. Posture was coded as sit/lie, stand, walk, or other using direct observation. Posture was classified using the activPAL software. Classification accuracy was evaluated using sensitivity, specificity and area under the receiver operating characteristic curve (ROC-AUC). Time spent in each posture and total number of breaks in SB were compared using paired sample t-tests. The activPAL showed good classification accuracy for sitting (ROC-AUC = 0.84) and fair classification accuracy for standing and walking (0.76 and 0.73, respectively). Time spent in sit/lie and stand was overestimated by 5.9% (95% CI = 0.6-11.1%) and 14.8% (11.6-17.9%), respectively; walking was underestimated by 10.0% (-12.9-7.0%). Total number of breaks in SB were significantly overestimated (55 ± 27 over the course of the protocol; p < .01). The activPAL performed well when classifying postures in young children. However, the activPAL has difficulty classifying other postures, such as kneeling. In addition, when predicting time spent in different postures and total number of breaks in SB the activPAL appeared not to be accurate.

  12. Numerical study on the impact of the 18.6-year period nodal tidal cycle on water masses in the subarctic North Pacific

    NASA Astrophysics Data System (ADS)

    Osafune, S.; Yasuda, I.

    2012-05-01

    A series of numerical experiments is performed to test the hypothesis that temporal variations in localized strong tidal mixing related to the 18.6-year period nodal tidal cycle induce water mass variations. It is suggested that enhanced mixing around the Bering Sea, as that around the Okhotsk Sea, have an impact on water masses broadly in the North Pacific including the Bering Sea and the Okhotsk Sea. Oscillatory tidal mixing with a 18.6-year period reproduces water mass variations in salinity and isopycnal potential temperature around the subarctic North Pacific that are qualitatively consistent with observed variations. When the amplitude of oscillatory vertical diffusivity is 15% of the long-term mean (and even when the amplitude is as small as 3 cm2/s, as obtained for a long-term mean of 20 cm2/s), the amplitude of the salinity variation near regions of strong mixing is smaller than but on the same order of magnitude as that observed. The induced salinity anomaly spreads broadly, over a distance of several hundreds of kilometers, by mean currents with a short lag time of less than 3 years, and is suggested to influence the model winter mixed layer over broad regions. These results support the hypothesis stated above and suggest that it is necessary to clarify spatial and temporal variations in tidal mixing to reproduce both the mean states of and temporal variations in water masses of the subarctic North Pacific.

  13. 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

  14. 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.

  15. Possible explanation linking 18.6-year period nodal tidal cycle with bi-decadal variations of ocean and climate in the North Pacific

    NASA Astrophysics Data System (ADS)

    Yasuda, Ichiro; Osafune, Satoshi; Tatebe, Hiroaki

    2006-04-01

    Bi-decadal climate variation is dominant over the North Pacific on inter-decadal timescale; however the mechanism has not been fully understood. We here find that the bi-decadal variations in the North Pacific climate and intermediate waters possibly relate to the 18.6-year period modulation of diurnal tide. In the period of strong diurnal tide, tide-induced diapycnal mixing makes surface salinity and density higher and the upper-layer shallower along the Kuril Islands and the east coast of Japan. Simple model results suggest that the coastal depth adjustment by baroclinic Kelvin waves enhances the thermohaline circulation, the upper-layer poleward western boundary current and associated heat transport by about 0.05PW. This could also explain the warmer SST in the Kuroshio-Oyashio Extension regions, where positive feedback with Aleutian Low might amplify the bidecadal variations. The 18.6-year tidal cycle hence could play a role as a basic forcing for the bi-decadal ocean and climate variations.

  16. Bidecadal variability in the intermediate waters of the northwestern subarctic Pacific and the Okhotsk Sea in relation to 18.6-year period nodal tidal cycle

    NASA Astrophysics Data System (ADS)

    Osafune, S.; Yasuda, I.

    2006-05-01

    On the basis of historical oceanographic data, we investigated the long-term variations of the intermediate waters in the four regions in the northwestern subarctic Pacific: Oyashio, Okhotsk Sea Mode Water, Upstream Oyashio and East Kamchatka Current. We found bidecadal oscillations in these water properties that are synchronized with the 18.6-year period nodal cycle. In periods when the diurnal tide is strong, the following characteristics are found: Apparent oxygen utilization and phosphate are low in Oyashio and Okhotsk Sea Mode Water. The thickness of the intermediate layers is large, and thus potential vorticity is correspondingly low, in Oyashio, Okhotsk Sea Mode Water, and Upstream Oyashio. Around the mesothermal (temperature maximum) water, isopycnal potential temperature are low in the areas on the Pacific side, and high in the intermediate layer of Okhotsk Sea Mode Water. The mixing ratio of Okhotsk Sea Mode Water in the Upstream Oyashio water is high. These bidecadal oscillations can be explained by changes in the vertical mixing around the Kuril Straits induced by the diurnal tide whose amplitude is modulated with the 18.6-year nodal cycle. Higher sea surface salinity water around the Kuril Straits caused by stronger tidal mixing is possibly transported northward along the cyclonic Okhotsk Sea Gyre, and possibly enhances the formation of the dense shelf water. This makes apparent oxygen utilization, phosphate, and potential vorticity lower in Okhotsk Sea Mode Water and Oyashio.

  17. Observation and modelling of turbulent mixing in the Kuril and Aleutian Straits and impact of its 18.6-year period tidal cycle on ocean and climate

    NASA Astrophysics Data System (ADS)

    Yasuda, I.; Tanaka, Y.; Itoh, S.; Hasumi, H.; Komatsu, K.; Osafune, S.; Yagi, M.; Tanaka, T.; Kaneko, H.; Ikeya, T.; Konda, S.; Nishioka, J.; Nakatsuka, T.; Katsumata, K.; Tatebe, H.; Watanabe, Y.; Hiroe, Y.; Nakamura, T.

    2012-12-01

    Direct turbulent observations in the Kuril Straits and Aleutian Straits reveal that tide-induced strong vertical mixing corresponds to strong shear of combined diurnal tidal and/or mean currents and significantly modifies the water-mass and potential vorticity distribution. Bi-decadal variability synchronized with 18.6-year period moon-tidal cycle were found in various parts of the ocean and climate indices: water-mass variability in the subarctic North Pacific, especially near the strong diurnal tide regions as Kuril Straits and Aleutian Islands, and in long-term climate indices as Pacific Decadal Oscillation (PDO) and El-Nino and Southern Oscillation (ENSO) in proxy-reconstructed records. In low-frequency part of the PDO and SOI records, negative (positive)-PDO and positive (negative)-SOI tend to occur in the 4-6-th (10-12-th) year after the maximum diurnal tide, which is consistent with the climate model experiments with locally enhanced vertical mixing around Kuril Straits showing that tidal mixing and its variability could generate bi-decadal variability in ocean and climate. Ocean and climate model experiments with parameterized tidal mixing explain some of the water-mass modifications and bi-decadal variability of water-masses and climate.

  18. Stability of Behavioral and Emotional Problems over 6 Years in Children Ages 4 to 5 or 6 to 7 at Time 1

    ERIC Educational Resources Information Center

    Bilancia, Sarah D.; Rescorla, Leslie

    2010-01-01

    This study tests the hypothesis that 6-year longitudinal stability of behavioral and emotional problems would be greater for children ages 6 to 7 than for those ages 4 to 5 at Time 1. Six-year outcome data for a nationally representative sample of 4- to 7-year-olds (N = 733) were used to examine longitudinal stability of internalizing,…

  19. [To maintain or to withdraw life support? Variations on the methods of ending life in a pediatric intensive care unit over a period of 6 years].

    PubMed

    Vernaz, S; Casanova, L; Blanc, F; Lebel, S; Ughetto, F; Paut, O

    2014-06-01

    Since 2005, forgoing live-support (FLS) is allowed by the French law (known as the Leonetti law) for end-of-life patients only. This study aims at describing the variations over time in the use of the following methods to end life: FLS, brain death and cardiopulmonary resuscitation failure (CPR failure). It is a single retrospective study from 2007 to 2012. The Cochran-Armitage trend test is used in the statistical analysis. Over six years, 263 of the 5100 children who were hospitalized in our intensive care unit died, which represents a 5.2% mortality rate. FLS increased yearly from 31% of the deaths in 2007, to 71% in 2012 (P=0.0008). The rate of CPR failure decreased over the same period (P=0.0015). The rate of brain death remained constant. Following to the Leonetti law, FLS increase, and palliative cares develop without any increase of mortality.

  20. 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

  1. 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....

  2. 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....

  3. 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....

  4. 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....

  5. Time domain period determination techniques

    NASA Technical Reports Server (NTRS)

    Stellingwerf, R. F.

    1980-01-01

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

  6. Time domain period determination techniques

    NASA Astrophysics Data System (ADS)

    Stellingwerf, R. F.

    1980-05-01

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

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. Rotorcraft Smoothing Via Linear Time Periodic Methods

    DTIC Science & Technology

    2007-07-01

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

  13. A 6-Year-Old With Leg Cramps.

    PubMed

    Jenssen, Brian P; Lautz, Andrew J; Orthmann-Murphy, Jennifer L; Yum, Sabrina W; Waanders, Angela; Fox, Elizabeth

    2015-10-01

    A 6-year-old girl presented with a history of leg pain and cramping that progressively worsened over a 2- to 3-week period of time. Her examination was notable for normal vital signs, limited range of motion of her left hip, and a limp. Inflammatory markers were slightly elevated, but the serum electrolytes, calcium, and magnesium, complete blood cell count and differential, and creatine kinase level were normal. She was hospitalized for further diagnostic evaluation and was noted to have abnormal muscle movements classified as myokymia (continuous involuntary quivering, rippling, or undulating movement of muscles). Electromyography confirmed the myokymia but did not reveal evidence of a myopathy or neuropathy, prompting additional evaluation for a systemic etiology.

  14. Shigellosis in Bay of Bengal Islands, India: clinical and seasonal patterns, surveillance of antibiotic susceptibility patterns, and molecular characterization of multidrug-resistant Shigella strains isolated during a 6-year period from 2006 to 2011.

    PubMed

    Bhattacharya, D; Bhattacharya, H; Thamizhmani, R; Sayi, D S; Reesu, R; Anwesh, M; Kartick, C; Bharadwaj, A P; Singhania, M; Sugunan, A P; Roy, S

    2014-02-01

    This study aims to determine the clinical features and seasonal patterns associated with shigellosis, the antimicrobial resistance frequencies of the isolates obtained during the period 2006-2012 for 22 antibiotics, and the molecular characterization of multidrug-resistant strains isolated from endemic cases of shigellosis in the remote islands of India, with special reference to fluoroquinolone and third-generation cephalosporins resistance. During the period from January 2006 to December 2011, stool samples were obtained and processed to isolate Shigella spp. The isolates were evaluated with respect to their antibiotic resistance pattern and various multidrug resistance determinants, including resistance genes, quinolone resistance determinants, and extended-spectrum β-lactamase (ESBL) production. Morbidity for shigellosis was found to be 9.3 % among children in these islands. Cases of shigellosis occurred mainly during the rainy seasons and were found to be higher in the age group 2-5 years. A wide spectrum of resistance was observed among the Shigella strains, and more than 50 % of the isolates were multidrug-resistant. The development of multidrug-resistant strains was found to be associated with various drug-resistant genes, multiple mutations in the quinolone resistance-determining region (QRDR), and the presence of plasmid-mediated quinolone-resistant determinants and efflux pump mediators. This report represents the first presentation of the results of long-term surveillance and molecular characterization concerning antimicrobial resistances in clinical Shigella strains in these islands. Information gathered as part of the investigations will be instrumental in identifying emerging antimicrobial resistance, for developing treatment guidelines appropriate for that community, and to provide baseline data with which to compare outbreak strains in the future.

  15. 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.

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  17. 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.

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 50 CFR 221.3 - How are time periods computed?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  3. 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...

  4. Detecting unstable periodic orbits from transient chaotic time series

    PubMed

    Dhamala; Lai; Kostelich

    2000-06-01

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

  5. 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.

  6. Student Instruction Should Be Distributed over Long Time Periods

    ERIC Educational Resources Information Center

    Rohrer, Doug

    2015-01-01

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

  7. Searching for periodicity in weighted time point series.

    NASA Astrophysics Data System (ADS)

    Jetsu, L.; Pelt, J.

    1996-09-01

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

  8. Luni-solar 18.6-year signal in tree-rings from Argentina and Chile

    NASA Astrophysics Data System (ADS)

    Cùrrie, Robert G.

    1991-09-01

    Spectrum analysis of 32 tree-ring chronologies from Argentina and Chile yields evidence for two peaks with periods 19.2±1.6 years (30 out of 32 records) and 10.5±0.4 years in 22 instances. Tests by the t-statistic show that the long-period peak is significant at a confidence level of 99%. This signal is identified as the luni-solar 18.6-year M n term reported earlier by Currie (1983) in two treering chronologies from the same region, and later in tree-rings from North America, Tasmania, New Zealand, and South Africa ( Currie, 1991a-c). Amplitude and phase of the M n signal are nonstationary with respect to both time and geography. In particular, abrupt 180° phase changes in wave polarity are often observed.

  9. 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

  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, 2013 CFR

    2013-04-01

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

  12. 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)...

  13. 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....

  14. 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)...

  15. 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)...

  16. 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...

  17. 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...

  18. 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...

  19. Persistence and Attainment of 2003-04 Beginning Postsecondary Students: After 6 Years. First Look. NCES 2011-151

    ERIC Educational Resources Information Center

    Radford, Alexandria Walton; Berkner, Lutz; Wheeless, Sara C.; Shepherd, Bryan

    2010-01-01

    This "First Look" presents findings from the 2004/09 Beginning Postsecondary Students Longitudinal Study (BPS:04/09), which collected information over a period of 6 years that describes the enrollment and employment experiences of a national sample of undergraduates who began their postsecondary education for the first time in the…

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

    NASA Astrophysics Data System (ADS)

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

    2002-07-01

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

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

    NASA Astrophysics Data System (ADS)

    Zhang, Liang; Wang, Zhi-Cheng

    2016-10-01

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

  2. Permutation test for periodicity in short time series data

    PubMed Central

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

    2006-01-01

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

  3. 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.

  4. Return times at periodic points in random dynamics

    NASA Astrophysics Data System (ADS)

    Haydn, Nicolai; Todd, Mike

    2017-01-01

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

  5. Observation of 18.6-year modulation tide at the South Pole

    NASA Astrophysics Data System (ADS)

    Rydelek, P. A.; Knopoff, L.; Zürn, W.

    1982-07-01

    We have observed long-period variations in the amplitudes of the diurnal and semidiurnal gravity tides at the South Pole which we attribute to the tidal effects of the 18.6-year regression of the nodes of the lunar orbit. The observations are in agreement with theoretical values of the 18.6-year amplitude modulation of these tides.

  6. Infrared Variability and Time Lags for Periodic Quasars

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

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

  7. Classical and revival time periods of confined harmonic oscillator

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

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

  9. Analysis of time-domain scattering by periodic structures

    NASA Astrophysics Data System (ADS)

    Gao, Yixian; Li, Peijun

    2016-11-01

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

  10. 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...

  11. 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...

  12. 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…

  13. 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...

  14. 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...

  15. High-latitude oceanic variability associated with the 18.6-year nodal tide

    NASA Astrophysics Data System (ADS)

    Royer, Thomas C.

    1993-03-01

    Ocean temperatures in the upper 250 m in the northern North Pacific (60°N, 149°W) increased by more than 1°C from 1972 to 1986 but are now decreasing. Subsurface temperature anomalies are well correlated (˜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°. 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.

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

    SciTech Connect

    Ambrose , D.M.; Wilkening, Jon

    2008-04-01

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

  17. A method for obtaining time-periodic Lp estimates

    NASA Astrophysics Data System (ADS)

    Kyed, Mads; Sauer, Jonas

    2017-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  19. The Dalhousie Family Therapy Training Program: Our 6-Year Experience

    PubMed Central

    Carrey, Normand; Costanzo, Lou; Sexton, Ann; Aspin, John

    2004-01-01

    Introduction Training in family therapy for general psychiatry residents during their child rotation is either not taught or the objectives not well described in psychiatric curricula. Method Based on the combined experience of 4 family therapists over a 6 year period with 56 students (psychiatry, social work, psychology), we describe our experience with training general psychiatry residents in an introduction to an interdisciplinary family therapy, systemic-reflective course during their child psychiatry rotation. The model was based on experiential training, where both trainees and supervisors could build skills as they reflect on their process as learners and teachers. Results Residents’ ratings at the end of rotation indicated extremely high satisfaction with the course. Conclusion We advocate that an experiential interdisciplinary course serving as an introduction to family assessment and systemic/reflective principles are valuable skills that have lasting value to general psychiatry residents. PMID:19030490

  20. 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

  1. 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.

  2. 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.

  3. 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.

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

    PubMed

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

    2012-12-01

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

  5. Transient habitats limit development time for periodical cicadas.

    PubMed

    Karban, Richard

    2014-01-01

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

  6. 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.

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

    NASA Astrophysics Data System (ADS)

    Currie, R. G.

    1981-11-01

    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.

  8. 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.

  9. 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.

  10. 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

    2016-07-01

    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

  11. 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.

  12. 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.

  13. 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.

  14. Simulation of estimating periodicity of seasonally stationary time series

    SciTech Connect

    Tian, C.J.

    1984-06-01

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

  15. 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.

  16. Navy Global Predictions for the Dynamo Time Period

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    NASA Technical Reports Server (NTRS)

    Ortega, Romeo; Albertos, Pedro; Lozano, Rogelio

    1988-01-01

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

  18. Children Learn Physical Skills. Volume 2. 4 to 6 Years.

    ERIC Educational Resources Information Center

    Diem, Liselott

    The physical development of the child from 4 to 6 years old is discussed. Activities and games that will increase the child's dexterity, balance, and ability to play with others are described and illustrated. (JD)

  19. Acute flaccid paralysis surveillance: A 6 years study, Isfahan, Iran

    PubMed Central

    Naeini, Alireza Emami; Ghazavi, Mohamadreza; Moghim, Sharareh; Sabaghi, Amirhosein; Fadaei, Reza

    2015-01-01

    Background: Poliomyelitis is still an endemic disease in many areas of the world including Africa and South Asia. Iran is polio free since 2001. However, due to endemicity of polio in neighboring countries of Iran, the risk of polio importation and re-emergence of wild polio virus is high. Case definition through surveillance system is a well-defined method for maintenance of polio eradication in polio free countries. Methods: In a cross-sectional survey from 2007 to 2013, we reviewed all the records of under 15 years old patients reported to Acute Flaccid Paralysis Committee (AFPC) in Isfahan province, Iran. All cases were visited by members of the AFPC. Three stool samples were collected from each reported case within 2 weeks of onset of paralysis and sent to National Polio Laboratory in Tehran, Iran, for poliovirus isolation. Data were analyzed by SSPS software (version 22). Student's t-test and Chi-square was used to compare variables. Statistical significance level was set at P < 0.05. Results: In this 6-year period 85 cases were analyzed, 54 patients were male (63.5%) and 31 were female (36.5%). The mean age of patients was 5.7 ± 3.9 years. The most common cause of paralysis among these patients was Guillian–Barré syndrome (83.5%). We did not found any poliomyelitis caused by wild polio virus. Only one case of vaccine associated poliomyelitis was reported. Conclusion: Since 1992, Iran has a routine and high percent coverage of polio vaccination program for infants (>94%), with six doses of oral polio vaccine (OPV). Accurate surveillance for poliomyelitis is essential for continuing eradication. PMID:26015925

  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. Extracting Binary Orbital Periods Using Timing Analysis of Microlensing Lightcurves

    NASA Astrophysics Data System (ADS)

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

    2012-01-01

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

  2. 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.

  3. 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.

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

    NASA Astrophysics Data System (ADS)

    She, M.; Jiang, L. P.

    2014-12-01

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

  5. 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…

  6. Intrinsic Periodicity of Time and Nonmaximal Entropy of Universe

    NASA Astrophysics Data System (ADS)

    Nielsen, Holger B.; Ninomiya, Masao

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

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

    SciTech Connect

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

    1989-12-01

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

  8. 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...

  9. 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.

  10. Periodization

    PubMed Central

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

    2010-01-01

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

  11. 36 CFR 218.10 - Objection time periods and process.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

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

    DTIC Science & Technology

    1988-05-01

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

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

    PubMed

    Zhao, Guangyu; Ruan, Shigui

    2011-06-01

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

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

    PubMed Central

    Zhao, Guangyu; Ruan, Shigui

    2011-01-01

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

  15. 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.

  16. 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.

  17. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

  19. Cat-scratch disease with severe pleuritis in a 6-year-old girl.

    PubMed

    Kimura, Sasagu; Hasegawa, Shunji; Yanagihara, Masashi; Inoue, Hirofumi; Matsushige, Takeshi; Tsuneoka, Hidehiro; Ichiyama, Takashi; Ohga, Shouichi

    2015-06-01

    We present the case of a 6-year-old girl with cat-scratch disease (CSD), who developed severe pleuritis without lymphadenitis. Bartonella henselae DNA was detected on real-time polymerase chain reaction (PCR) analysis of whole blood. This is the first report of CSD diagnosed on real-time PCR using whole blood.

  20. Progression of motor subtypes in Huntington's disease: a 6-year follow-up study.

    PubMed

    Jacobs, M; Hart, E P; van Zwet, E W; Bentivoglio, A R; Burgunder, J M; Craufurd, D; Reilmann, R; Saft, C; Roos, R A C

    2016-10-01

    The objective of this study is to investigate the progression of predominantly choreatic and hypokinetic-rigid signs in Huntington's disease (HD) and their relationship with cognitive and general functioning over time. The motor signs in HD can be divided into predominantly choreatic and hypokinetic-rigid subtypes. It has been reported in cross-sectional studies that predominantly choreatic HD patients perform better on functional and cognitive assessments compared to predominantly hypokinetic-rigid HD patients. The course of these motor subtypes and their clinical profiles has not been investigated longitudinally. A total of 4135 subjects who participated in the European HD Network REGISTRY study were included and classified at baseline as either predominantly choreatic (n = 891), hypokinetic-rigid (n = 916), or mixed-motor (n = 2328), based on a previously used method. The maximum follow-up period was 6 years. The mixed-motor group was not included in the analyses. Linear mixed models were constructed to investigate changes in motor subtypes over time and their relationship with cognitive and functional decline. Over the 6-year follow-up period, the predominantly choreatic group showed a significant decrease in chorea, while hypokinetic-rigid symptoms slightly increased in the hypokinetic-rigid group. On the Total Functional Capacity, Stroop test, and Verbal fluency task the rate of change over time was significantly faster in the predominantly choreatic group, while on all other clinical assessments the decline was comparable for both groups. Our results suggest that choreatic symptoms decrease over time, whereas hypokinetic-rigid symptoms slightly increase in a large cohort of HD patients. Moreover, different motor subtypes can be related to different clinical profiles.

  1. 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.

  2. Edwards syndrome in a 6-year old girl.

    PubMed

    Raczkowski, Jan W; Daniszewska, Barbara; Paradecka, Anna

    2010-01-01

    Trisomy 18 (Edwards syndrome - ES) is the second most common trisomy. It occurs in 1/3 000 to 1/8 000 births. ES is a cause of numerous developmental disorders and malformations. The median life span of children with ES is about 2 weeks and only 5%-10% will survive their first year of life. The report presents a case of a 6-year-old girl with ES.

  3. Expressed emotion, family environment, and parental bonding in bulimia nervosa: a 6-year investigation.

    PubMed

    Hedlund, S; Fichter, M M; Quadflieg, N; Brandl, C

    2003-03-01

    As part of a prospective, long-term treatment study, 30 in-patients with bulimia nervosa (BN) were divided into groups with high and low expressed emotion (EE) family backgrounds according to the Camberwell Family Interview, and followed for a period of six years. The high EE group initially showed significantly more psychopathology than the low EE group. No group x time interactions were found, but the high EE group showed a worse outcome on the "conflict" and "organisation" subscales of the Family Environment Scale. They also showed significantly more eating disorder pathology according to the Eating Disorder Inventory (EDI) and the Structured Interview for anorexia nervosa (AN) and BN before treatment at discharge, after two years and, to some degree, even after six years. Depth of depression (Beck Depression Inventory) was significantly higher in the high EE group at admission (moderate depression), discharge and after the 6-year follow-up (still slight depression). The Parental Bonding Instrument (PBI) showed no differences between the high EE and low EE groups, but the individuals with "affectionless control" according to the PBI had more negative scores on three of the subscales of the Family Environment Scale (FES). In brief, the high EE individuals with BN were initially sicker and did not fully catch up over time in comparison with the symptomatic recovery of the low EE individuals. These data suggest that EE status upon admission to in-patient treatment is a relevant predictor of the severity and course of BN and depressive symptoms.

  4. 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

  5. The Diagnosis and Treatment of Multiple Factitious Oral Ulcers in a 6-Year-Old Boy

    PubMed Central

    Gonçalves, Priscilla Santana Pinto; Mendez, Daniela Alejandra Cusicanqui; Damante, José Humberto; Rios, Daniela

    2017-01-01

    Factitious ulcers are characterized by self-inflicted lesions with multifactorial origin. These lesions are frequently found in head, neck, and hands. This report shows a 6-year-old boy diagnosed with factitious oral ulcers that occurred after the self-biting of buccal vestibule and nail-scratching of gingival tissue. Clinically, a significant swelling was observed, hard on palpation, located at the right lower third of the face, next to the posterior area of the mandible. In the intraoral examination, ulcers at different healing stages were noted on the swelling area. During the anamnesis, the father reported a change in his familial structure that triggers psychological stress, providing the clues to the presumptive diagnosis of factitious oral ulcers. We prescribed the topical use of Gingilone® three times a day to control the local pain and inflammation. At 7-day follow-up, we noticed the reduction of extraoral swelling and the initial healing of the ulcers. The presumptive diagnosis was confirmed at 30-day follow-up, with the lasting remission of oral lesions. The treatments of factitious oral ulcers should be individually tailored for each patient, focused on a multidisciplinary approach, including psychotherapy and periodic clinical control. To the best of our knowledge, gaps of evidence lead to the lack of standardized clinical protocols on this issue. PMID:28293440

  6. The Diagnosis and Treatment of Multiple Factitious Oral Ulcers in a 6-Year-Old Boy.

    PubMed

    Gonçalves, Priscilla Santana Pinto; Mendez, Daniela Alejandra Cusicanqui; Santos, Paulo Sérgio da Silva; Damante, José Humberto; Rios, Daniela; Cruvinel, Thiago

    2017-01-01

    Factitious ulcers are characterized by self-inflicted lesions with multifactorial origin. These lesions are frequently found in head, neck, and hands. This report shows a 6-year-old boy diagnosed with factitious oral ulcers that occurred after the self-biting of buccal vestibule and nail-scratching of gingival tissue. Clinically, a significant swelling was observed, hard on palpation, located at the right lower third of the face, next to the posterior area of the mandible. In the intraoral examination, ulcers at different healing stages were noted on the swelling area. During the anamnesis, the father reported a change in his familial structure that triggers psychological stress, providing the clues to the presumptive diagnosis of factitious oral ulcers. We prescribed the topical use of Gingilone® three times a day to control the local pain and inflammation. At 7-day follow-up, we noticed the reduction of extraoral swelling and the initial healing of the ulcers. The presumptive diagnosis was confirmed at 30-day follow-up, with the lasting remission of oral lesions. The treatments of factitious oral ulcers should be individually tailored for each patient, focused on a multidisciplinary approach, including psychotherapy and periodic clinical control. To the best of our knowledge, gaps of evidence lead to the lack of standardized clinical protocols on this issue.

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

    NASA Astrophysics Data System (ADS)

    Tong, Hao; Xu, Ren-Xin

    2013-10-01

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

  8. 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.

  9. 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...

  10. 14 CFR 135.273 - Duty period limitations and rest time requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

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

  11. 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...

  12. 14 CFR 135.273 - Duty period limitations and rest time requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

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

  13. 14 CFR 135.273 - Duty period limitations and rest time requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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

  14. 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.

  15. 21 CFR 60.28 - Time frame for determining regulatory review periods.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  16. 33 CFR 164.55 - Deviations from rules: Continuing operation or period of time.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  17. 21 CFR 60.28 - Time frame for determining regulatory review periods.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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

  18. 47 CFR 54.724 - Time periods for Commission approval of Administrator decisions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

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

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. Contact dermatitis in children: 6 years experience (1992-1997).

    PubMed

    Romaguera, C; Vilaplana, J

    1998-12-01

    We report the results of patch tests carried out over the last 6 years (1992 1997) on 141 children. This corresponds to 2.8% of the total patients who were patch tested in our Allergy Department (5,014). These 141 children were patch tested using the TRUE Test standard series and an additional allergen, metallic mercury. Allergens from the Chemotechnique medicaments, cosmetics, plants and shoe series were added in some. The most frequent localization of eczema was to the feet, face and hands and the most frequent suspected causes were costume jewelry, footwear, topical medicaments and cosmetics. The most frequent allergens, assessed by degree of relevance, were first, nickel, followed by cobalt, mercurials (thimerosal and metallic mercury), fragrance and rubber chemicals (naphthyl mix, mercapto mix, carba mix and PPD mix). 13 children, 18% of the total, between the ages of 12 and 14 years, showed positivities relevant to some occupation, i.e., metalworking, building, hairdressing, catering, etc. Once patch tests had been carried out and relevant positive patch tests assessed, the most frequent diagnoses were contact dermatitis 45%, atopic dermatitis 25%, juvenile plantar dermatitis 15%, and other diagnoses in the remaining 15%.

  5. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

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

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

    SciTech Connect

    Reno, Matthew J.; Hansen, Clifford W.

    2016-01-18

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

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

    NASA Astrophysics Data System (ADS)

    Harman, Ciaran; Kim, Minseok

    2014-05-01

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

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

    NASA Astrophysics Data System (ADS)

    Cheng, Ming

    2017-04-01

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

  11. 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.

  12. 40 CFR 93.162 - Emissions beyond the time period covered by the SIP.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  14. 40 CFR 93.162 - Emissions beyond the time period covered by the SIP.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  15. 40 CFR 93.162 - Emissions beyond the time period covered by the SIP.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

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

    NASA Astrophysics Data System (ADS)

    Benacka, Jan

    2017-03-01

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

  17. 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.

  18. Possible damping model of the 6 year oscillation signal in length of day

    NASA Astrophysics Data System (ADS)

    Duan, Pengshuo; Liu, Genyou; Hu, Xiaogang; Sun, Yafei; Li, Honglei

    2017-04-01

    A significant 6 year oscillation signal exists in the observed length-of-day (LOD) series. We recently used normal Morlet wavelet transform method to recover this oscillation signal. The result indicates that the amplitude of this oscillation has been decreasing for the over past 50 years. Using the simulation analysis, this study further demonstrates that the above result is reliable. However, the geophysical mechanism responsible for this decrease is less clear. Here, we develop a temporal-decaying function to characterize the secular attenuation of the oscillation signal. Using the least squared method, we obtain the corresponding quality factor Q value (51.6 ± 0.4) and the damping relaxation time τ (99.2 ± 0.8 years). We find the attenuation of the 6 year oscillation signal and its Q value can be explained by previous theoretical prediction, providing constraints on the related physical parameters of the lowermost mantle. The dissipative effect of electromagnetic coupling at the core-mantle boundary is likely to be a primary factor to cause the decaying of the 6 year oscillation signal.

  19. 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.

  20. 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…

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

    DTIC Science & Technology

    1991-07-26

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

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

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

    NASA Astrophysics Data System (ADS)

    Maamache, Mustapha; Lamri, Sarra; Cherbal, Omar

    2017-03-01

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

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

    PubMed

    Giertsen, Merethe; Anderssen, Norman

    2007-11-01

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

  5. 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.

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

    NASA Astrophysics Data System (ADS)

    D'Alessio, Luca; Rigol, Marcos

    2014-10-01

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

  7. 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.

  8. 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.

  9. 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

  10. 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.

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

    PubMed

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

    2012-06-01

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

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

    NASA Technical Reports Server (NTRS)

    Hou, Lin-Jun; Peters, David A.

    1991-01-01

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

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

    PubMed

    Huttenlocher, J; Levine, S; Vevea, J

    1998-08-01

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

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

    DOE PAGES

    Reno, Matthew J.; Hansen, Clifford W.

    2016-01-18

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

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

    SciTech Connect

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

    1992-09-15

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

  16. 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.

  17. 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.

  18. 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…

  19. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2006-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

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

  2. Child abuse-related homicides in New Mexico: a 6-year retrospective review.

    PubMed

    Lee, Carol K; Lathrop, Sarah L

    2010-01-01

    We retrospectively reviewed autopsy records at a statewide medical examiner's office in order to identify and characterize deaths due to child abuse. In a 6-year period in New Mexico, the medical examiner investigated 45 deaths determined to be child abuse-related. Decedents were predominantly male (68.9%), Hispanic White (53.3%), and all were 5 years of age or younger, with a median age of 1 year. Head injuries were the most common cause of death (44.4%), followed by battered baby syndrome (15.6%). Relatives were involved as alleged perpetrators in 80% of the cases, with the father most often implicated (36.1% of cases), and 88.9% of child abuse injuries resulting in death occurred in the family's residence. Toxicology was positive in 26.7% of cases, but only two cases had substances of abuse present. Information on risk factors such as prematurity, parental age, and history of abuse was also collected.

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

    NASA Astrophysics Data System (ADS)

    Zorzenon dos Santos, Rita Maria

    1993-05-01

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

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

    PubMed

    Pawłowski, Filip; Olsen, Jeppe; Jørgensen, Poul

    2015-03-21

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

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

  6. 33 CFR 164.55 - Deviations from rules: Continuing operation or period of time.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  7. 9 CFR 201.217 - Reasonable period of time to remedy a breach of contract.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

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

  8. 9 CFR 201.217 - Reasonable period of time to remedy a breach of contract.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

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

  9. 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…

  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. 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…

  12. 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

  13. Reliability of the Strengths and Difficulties Questionnaire in Japanese Preschool Children Aged 4–6 Years

    PubMed Central

    Doi, Yuriko; Ishihara, Kaneyoshi; Uchiyama, Makoto

    2014-01-01

    Background The Strengths and Difficulties Questionnaire (SDQ) has been widely used as a brief behavioral screening. The aim of this study was to examine the internal consistency and test-retest reliability of the 3- to 4-year-old version of the SDQ (SDQ 3–4) in Japanese preschool children. Methods The SDQ 3–4 was administered to 754 parents who had 4- to 6-year-old children attending kindergartens or childcare centers in Wako City, Japan, at 2 different times (Time 1 and Time 2) over a 2-week interval between June and July 2012. Cronbach’s α and correlation coefficients were used to examine internal consistency and test-retest reliability, respectively. Results Of 393 parents who returned their responses at Time 1 (response rate 52.1%), 383 were used for analysis after excluding 10 responses with missing data. Their children’s mean age was 4.7 (standard deviation 0.7) years. The internal consistency (Cronbach’s α) was good for the total difficulties score (0.74) and the prosocial behavior scale (0.70). However, it was slightly worse for the emotional symptoms, conduct problems, and hyperactivity scales (0.61–0.66) and poor for the peer problems scale (0.45). Of the 383 included respondents at Time 1, 211 parents returned their responses at Time 2 (response rate: 55.1%). Test-retest reliability (correlation coefficients) was good (0.73–0.82), except for the peer problems scale (0.58). Conclusions The results support the reliability of the SDQ 3–4 being satisfactory for the total difficulties score and prosocial behavior scale and being acceptable for the emotional symptoms, conduct problems, and hyperactivity scales in Japanese preschool children aged 4–6 years. PMID:25373462

  14. 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

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

    PubMed

    Saiki, Yoshitaka; Yamada, Michio

    2009-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2002-01-01

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

  17. 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.

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

    NASA Astrophysics Data System (ADS)

    Gopinath, Arathi Kamath

    2007-12-01

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

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

    SciTech Connect

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

    2016-03-20

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

  20. 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

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

    NASA Astrophysics Data System (ADS)

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

    2017-03-01

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

  2. 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.

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

    PubMed

    Richardson, Brian A; Balasubramaniam, Ramesh

    2010-01-18

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

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

    NASA Astrophysics Data System (ADS)

    Combescure, Monique

    2006-03-01

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

  5. 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.

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

    NASA Astrophysics Data System (ADS)

    Iwamoto, Kazuki; Dohi, Tadashi; Kaio, Naoto

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

  7. 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.

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

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

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

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  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

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

  11. Significant contribution of the 18.6 year tidal cycle to regional coastal changes

    NASA Astrophysics Data System (ADS)

    Gratiot, N.; Anthony, E. J.; Gardel, A.; Gaucherel, C.; Proisy, C.; Wells, J. T.

    2008-03-01

    Although rising global sea levels will affect the shape of coastlines over the coming decades, the most severe and catastrophic shoreline changes occur as a consequence of local and regional-scale processes. Changes in sediment supply and deltaic subsidence, both natural or anthropogenic, and the occurrences of tropical cyclones and tsunamis have been shown to be the leading controls on coastal erosion. Here, we use satellite images of South American mangrove-colonized mud banks collected over the past twenty years to reconstruct changes in the extent of the shoreline between the Amazon and Orinoco rivers. The observed timing of the redistribution of sediment and migration of the mud banks along the 1,500km muddy coast suggests the dominant control of ocean forcing by the 18.6 year nodal tidal cycle. Other factors affecting sea level such as global warming or El Niño and La Niña events show only secondary influences on the recorded changes. In the coming decade, the 18.6 year cycle will result in an increase of mean high water levels of 6cm along the coast of French Guiana, which will lead to a 90m shoreline retreat.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  13. Assessment of Working Memory Components at 6 Years of Age as Predictors of Reading Achievements a Year Later

    ERIC Educational Resources Information Center

    Nevo, Einat; Breznitz, Zvia

    2011-01-01

    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 6 years of age, before reading was taught, to predict reading abilities (decoding, reading comprehension, and reading time) a year later was examined in 97…

  14. Kinship Center Attachment Questionnaire: Development of a Caregiver-Completed Attachment Measure for Children Younger than 6 Years

    ERIC Educational Resources Information Center

    Kappenberg, Erin Setsuko; Halpern, Diane F.

    2006-01-01

    The Kinship Center Attachment Questionnaire (KCAQ) is a newly developed screening instrument completed by the caregiver and appropriate for use with children younger than 6 years. The KCAQ is different from other attachment instruments because it is a time-efficient, quantitative measure of child attachment that is capable of tracking change in…

  15. Stochastic model stationarization by eliminating the periodic term and its effect on time series prediction

    NASA Astrophysics Data System (ADS)

    Moeeni, Hamid; Bonakdari, Hossein; Fatemi, Seyed Ehsan

    2017-04-01

    Because time series stationarization has a key role in stochastic modeling results, three methods are analyzed in this study. The methods are seasonal differencing, seasonal standardization and spectral analysis to eliminate the periodic effect on time series stationarity. First, six time series including 4 streamflow series and 2 water temperature series are stationarized. The stochastic term for these series obtained with ARIMA is subsequently modeled. For the analysis, 9228 models are introduced. It is observed that seasonal standardization and spectral analysis eliminate the periodic term completely, while seasonal differencing maintains seasonal correlation structures. The obtained results indicate that all three methods present acceptable performance overall. However, model accuracy in monthly streamflow prediction is higher with seasonal differencing than with the other two methods. Another advantage of seasonal differencing over the other methods is that the monthly streamflow is never estimated as negative. Standardization is the best method for predicting monthly water temperature although it is quite similar to seasonal differencing, while spectral analysis performed the weakest in all cases. It is concluded that for each monthly seasonal series, seasonal differencing is the best stationarization method in terms of periodic effect elimination. Moreover, the monthly water temperature is predicted with more accuracy than monthly streamflow. The criteria of the average stochastic term divided by the amplitude of the periodic term obtained for monthly streamflow and monthly water temperature were 0.19 and 0.30, 0.21 and 0.13, and 0.07 and 0.04 respectively. As a result, the periodic term is more dominant than the stochastic term for water temperature in the monthly water temperature series compared to streamflow series.

  16. 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

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

    SciTech Connect

    Yang, Ping-Fan; Guo, Yong

    2016-02-01

    We investigate the tunneling time (dwell time) in periodic diluted-magnetic-semiconductor/nonmagnetic-barrier (DMS/NB) superlattices subjected to an external magnetic field. It is found that spin-dependent resonant bands form in the spectra of dwell time, which can be effectively manipulated by not only the external magnetic field but also the geometric parameters of the system. Moreover, an intuitive semiclassical delay is defined to illustrate the behavior of the dwell time, and the former one is shown to be the result of “smoothing out” the latter one. We also find that the dwell time in diluted-magnetic-semiconductor/semiconductor superlattices behaves surprisingly different from the DMS/NB case, especially for spin-down electrons.

  18. Lack of progressive reduction in P3 amplitude after the first-episode of schizophrenia: A 6-year follow-up study.

    PubMed

    Devrim-Üçok, Müge; Keskin-Ergen, Yasemin; Üçok, Alp

    2016-09-30

    P3 event-related potential may track the course of neurophysiological pathology in schizophrenia. Reduction in the amplitude of the auditory P3 is a widely replicated finding, already present at the first psychotic episode, in schizophrenia. Whether a progressive deficit is present in auditory P3 in schizophrenia over the course of illness is yet to be clarified. Previous longitudinal studies did not report any change in P3 over time in schizophrenia. However, these studies have been inconclusive, because of their relatively short follow-up periods, lack of follow-up data on controls, and assessment of patients already at the chronic stages of schizophrenia. Auditory P3 potentials, elicited by an oddball paradigm, were assessed in 14 patients with first-episode schizophrenia and 22 healthy controls at baseline and at the 6-year follow-up. P3 amplitudes were smaller in patients with first-episode schizophrenia than in controls. Importantly, over the 6-year interval, the P3 amplitudes were reduced in controls, but they did not change in patients. The lack of P3 reduction over time in patients with schizophrenia might be explained by the maximal reduction in P3 already at baseline or by the alleviation of P3 reduction over time.

  19. Why the 18.6 year tide cannot explain the change of sign observed in j2

    NASA Astrophysics Data System (ADS)

    Deleflie, F.; Exertier, P.; Metris, G.; Berio, P.; Laurain, O.; Lemoine, J.-M.; Biancale, R.

    2003-06-01

    Recent studies show a change, starting in 1998, in the behavior of the variation of the dynamical flattening of the Earth (J2), supposed to be constant (secular), and mainly due to the post glacial rebound effect. In this paper, we study to what extent this behavior can be correlated or not with the 18.6 year tide: with more than twenty years of tracking data on LAGEOS-1, that is to say more than a period of 18.6 years, this effect can now be separated from the secular variation. We use our theory of mean orbital motion, dedicated to studies of the long period effects on the orbital motion. We build one single arc of LAGEOS-1 from 1980 to 2002, which provides a continuous description of the orbital parameters. This is the great originality of our approach. We focus our attention on the ascending node of LAGEOS-1, and we show that the change observed in j2 cannot be attributed to a statistical error due to a correlation, in short arcs results, between the secular variation of J2 and the 18.6 year tide. The proof is based on the adjustment of amplitudes and phases of the long period tides, and on the shape of the residuals.

  20. 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

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

    PubMed

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

    2015-08-21

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

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. Real-time Periodic Processing of RT-middleware Utilizing Linux Standard Functionalities

    NASA Astrophysics Data System (ADS)

    Shimizu, Masaharu; Toda, Kengo; Hayashibara, Yasuo; Yamato, Hideaki; Furuta, Takayuki

    A new methodology of real-time periodic processing on RT-middleware based on the Linux standard functionalities is presented in this paper. The central of discussion is on the realization of real-time processing while keeping the reusability of software modules ensured by the RT-middleware framework as well as the portability provided by the Linux development mainstream. In order to show the validity of the proposed approach, two robot systems, including an omnidirectional electric wheelchair steered by haptic joystick, are presented and the discussion about the evaluation result follows from the view point of practicality.

  9. Delayed state feedback and chaos control for time-periodic systems via a symbolic approach

    NASA Astrophysics Data System (ADS)

    Ma, Haitao; Deshmukh, Venkatesh; Butcher, Eric; Averina, Victoria

    2005-08-01

    This paper presents a symbolic method for a delayed state feedback controller (DSFC) design for linear time-periodic delay (LTPD) systems that are open loop unstable and its extension to incorporate regulation and tracking of nonlinear time-periodic delay (NTPD) systems exhibiting chaos. By using shifted Chebyshev polynomials, the closed loop monodromy matrix of the LTPD system (or the linearized error dynamics of the NTPD system) is obtained symbolically in terms of controller parameters. The symbolic closed loop monodromy matrix, which is a finite dimensional approximation of an infinite dimensional operator, is used in conjunction with the Routh-Hurwitz criterion to design a DSFC to asymptotically stabilize the unstable dynamic system. Two controllers designs are presented. The first design is a constant gain DSFC and the second one is a periodic gain DSFC. The periodic gain DSFC has a larger region of stability in the parameter space than the constant gain DSFC. The asymptotic stability of the LTPD system obtained by the proposed method is illustrated by asymptotically stabilizing an open loop unstable delayed Mathieu equation. Control of a chaotic nonlinear system to any desired periodic orbit is achieved by rendering asymptotic stability to the error dynamics system. To accommodate large initial conditions, an open loop controller is also designed. This open loop controller is used first to control the error trajectories close to zero states and then the DSFC is switched on to achieve asymptotic stability of error states and consequently tracking of the original system states. The methodology is illustrated by two examples.

  10. Neural spike-timing patterns vary with sound shape and periodicity in three auditory cortical fields.

    PubMed

    Lee, Christopher M; Osman, Ahmad F; Volgushev, Maxim; Escabí, Monty A; Read, Heather L

    2016-04-01

    Mammals perceive a wide range of temporal cues in natural sounds, and the auditory cortex is essential for their detection and discrimination. The rat primary (A1), ventral (VAF), and caudal suprarhinal (cSRAF) auditory cortical fields have separate thalamocortical pathways that may support unique temporal cue sensitivities. To explore this, we record responses of single neurons in the three fields to variations in envelope shape and modulation frequency of periodic noise sequences. Spike rate, relative synchrony, and first-spike latency metrics have previously been used to quantify neural sensitivities to temporal sound cues; however, such metrics do not measure absolute spike timing of sustained responses to sound shape. To address this, in this study we quantify two forms of spike-timing precision, jitter, and reliability. In all three fields, we find that jitter decreases logarithmically with increase in the basis spline (B-spline) cutoff frequency used to shape the sound envelope. In contrast, reliability decreases logarithmically with increase in sound envelope modulation frequency. In A1, jitter and reliability vary independently, whereas in ventral cortical fields, jitter and reliability covary. Jitter time scales increase (A1 < VAF < cSRAF) and modulation frequency upper cutoffs decrease (A1 > VAF > cSRAF) with ventral progression from A1. These results suggest a transition from independent encoding of shape and periodicity sound cues on short time scales in A1 to a joint encoding of these same cues on longer time scales in ventral nonprimary cortices.

  11. Stability and predictive value of anti-JCV antibody index in multiple sclerosis: A 6-year longitudinal study

    PubMed Central

    Auer, Michael; Bsteh, Gabriel; Di Pauli, Franziska; Plavina, Tatiana; Walde, Janette; Deisenhammer, Florian; Berger, Thomas

    2017-01-01

    Background Risk of natalizumab-related progressive multifocal leukoencephalopathy is associated with the presence of anti-JC-virus (JCV) antibodies. Objective To investigate the longitudinal evolution of anti-JCV antibody index and to determine the predictive value of baseline anti-JCV antibody index for long-term stability of anti-JCV antibody status. Methods MS patients from the MS centre of Medical University of Innsbruck, who had serum sampling for a time period of 4–6 years at intervals of 6±3 months, were included in this retrospective, longitudinal study. Anti-JCV antibody serological status and index were determined by 2-step second-generation anti-JCV antibody assay. Results 154 patients were included in this study. Median follow-up time was 63.7 months, with median 11 samples available per patient. At baseline, 111 (72.1%) patients were anti-JCV antibody positive. Baseline anti-JCV antibody index significantly correlated with age (R = 0.22, p = 0.005); there was no difference with respect to sex, disease duration or previously used disease-modifying treatment. During follow-up anti-JCV antibody status changed from negative to positive or vice versa in 17% of patients. In seronegative patients at baseline, baseline anti-JCV antibody index was significantly lower in those remaining seronegative at follow-up compared to those converting to seropositivity (median 0.16 vs. 0.24, p = 0.002). In seropositive patients at baseline, index was higher in those remaining seropositive compared to those reverting to seronegativity (2.6 vs. 0.45, p<10−7). Baseline anti-JCV antibody index >0.90 predicted stable positive serostatus (sensitivity 88.7%, specificity 96.5%) and <0.20 stable negative serostatus (sensitivity 61.3%, specificity 97.6%). Conclusions Anti-JCV antibody index remained relatively stable over 6-year follow-up with annual serostatus change of ~3%. Baseline anti-JCV antibody index predicted stable negative and stable positive JCV serostatus. PMID

  12. Scald management protocols - outcome differences in two different time periods using different treatment strategies

    PubMed Central

    Elmasry, M.; Steinvall, I.; Thorfinn, J.; Abbas, A.H..; Adly, O.A.; Abdelrahman, I.; Nagi, M.A.; Sjoberg, F.

    2016-01-01

    Summary Over the years the treatment of scalds in our centre has changed, moving more towards the use of biological dressings (xenografts). Management of scalds with mid dermal or deep dermal injuries differs among centers using different types of dressings, and recently biological membrane dressings were recommended for this type of injury. Here we describe differences in treatment outcome in different periods of time. All patients with scalds who presented to the Linkoping Burn Centre during two periods, early (1997-98) and later (2010-12) were included. Data were collected in the unit database and analyzed retrospectively. A lower proportion of autograft operations was found in the later period, falling from 32% to 19%. Hospital stay was shorter in the later period (3.5 days shorter, p=0.01) and adjusted duration of hospital stay/TBSA% was shorter (1.2 to 0.7, p=0.07). The two study groups were similar in most of the studied variables: we could not report any significant differences regarding outcome except for unadjusted duration of hospital stay. Further studies are required to investigate functional and aesthetic outcome differences between the treatment modalities. PMID:28149237

  13. Scald management protocols - outcome differences in two different time periods using different treatment strategies.

    PubMed

    Elmasry, M; Steinvall, I; Thorfinn, J; Abbas, A H; Adly, O A; Abdelrahman, I; Nagi, M A; Sjoberg, F

    2016-06-30

    Over the years the treatment of scalds in our centre has changed, moving more towards the use of biological dressings (xenografts). Management of scalds with mid dermal or deep dermal injuries differs among centers using different types of dressings, and recently biological membrane dressings were recommended for this type of injury. Here we describe differences in treatment outcome in different periods of time. All patients with scalds who presented to the Linkoping Burn Centre during two periods, early (1997-98) and later (2010-12) were included. Data were collected in the unit database and analyzed retrospectively. A lower proportion of autograft operations was found in the later period, falling from 32% to 19%. Hospital stay was shorter in the later period (3.5 days shorter, p=0.01) and adjusted duration of hospital stay/TBSA% was shorter (1.2 to 0.7, p=0.07). The two study groups were similar in most of the studied variables: we could not report any significant differences regarding outcome except for unadjusted duration of hospital stay. Further studies are required to investigate functional and aesthetic outcome differences between the treatment modalities.

  14. Finite-difference Time-domain Modeling of Laser-induced Periodic Surface Structures

    NASA Astrophysics Data System (ADS)

    Römer, G. R. B. E.; Skolski, J. Z. P.; Oboňa, J. Vincenc; Veld, A. J. Huis in't.

    Laser-induced periodic surface structures (LIPSSs) consist of regular wavy surface structures with amplitudes the (sub)micrometer range and periodicities in the (sub)wavelength range. It is thought that periodically modulated absorbed laser energy is initiating the growth of LIPSSs. The "Sipe theory" (or "Efficacy factor theory") provides an analytical model of the interaction of laser radiation with a rough surface of the material, predicting modulated absorption just below the surface of the material. To address some limitations of this model, the finite-difference time-domain (FDTD) method was employed to numerically solve the two coupled Maxwell's curl equations, for linear, isotropic, dispersive materials with no magnetic losses. It was found that the numerical model predicts the periodicity and orientation of various types of LIPSSs which might occur on the surface of the material sample. However, it should be noted that the numerical FDTD model predicts the signature or "fingerprints" of several types of LIPSSs, at different depths, based on the inhomogeneously absorbed laser energy at those depths. Whether these types of (combinations of) LIPSSs will actually form on a material will also depend on other physical phenomena, such as the excitation of the material, as well as thermal-mechanical phenomena, such as the state and transport of the material.

  15. Detection of faults in rotating machinery using periodic time-frequency sparsity

    NASA Astrophysics Data System (ADS)

    Ding, Yin; He, Wangpeng; Chen, Binqiang; Zi, Yanyang; Selesnick, Ivan W.

    2016-11-01

    This paper addresses the problem of extracting periodic oscillatory features in vibration signals for detecting faults in rotating machinery. To extract the feature, we propose an approach in the short-time Fourier transform (STFT) domain where the periodic oscillatory feature manifests itself as a relatively sparse grid. To estimate the sparse grid, we formulate an optimization problem using customized binary weights in the regularizer, where the weights are formulated to promote periodicity. In order to solve the proposed optimization problem, we develop an algorithm called augmented Lagrangian majorization-minimization algorithm, which combines the split augmented Lagrangian shrinkage algorithm (SALSA) with majorization-minimization (MM), and is guaranteed to converge for both convex and non-convex formulation. As examples, the proposed approach is applied to simulated data, and used as a tool for diagnosing faults in bearings and gearboxes for real data, and compared to some state-of-the-art methods. The results show that the proposed approach can effectively detect and extract the periodical oscillatory features.

  16. 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.

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

    NASA Astrophysics Data System (ADS)

    Deinega, Alexei; Belousov, Sergei; Valuev, Ilya

    2013-11-01

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

  18. 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.

  19. 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

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

    NASA Astrophysics Data System (ADS)

    Fu, Congsheng; Ji, Zhenming; Wei, Zhongwang

    2017-04-01

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

  1. Asynchronous Periodic Edge-Event Triggered Control for Double-Integrator Networks With Communication Time Delays.

    PubMed

    Duan, Gaopeng; Xiao, Feng; Wang, Long

    2017-01-23

    This paper focuses on the average consensus of double-integrator networked systems based on the asynchronous periodic edge-event triggered control. The asynchronous property lies in the edge event-detecting procedure. For different edges, their event detections are performed at different times and the corresponding events occur independently of each other. When an event is activated, the two adjacent agents connected by the corresponding link sample their relative state information and update their controllers. The application of incidence matrix facilitates the transformation of control objects from the agent-based to the edge-based. Practically, due to the constraints of network bandwidth and communication distance, agents usually cannot receive the instantaneous information of some others, which has an impact on the system performance. Hence, it is necessary to investigate the presence of communication time delays. For double-integrator multiagent systems with and without communication time delays, the average state consensus can be asynchronously achieved by designing appropriate parameters under the proposed event-detecting rules. The presented results specify the relationship among the maximum allowable time delays, interaction topologies, and event-detecting periods. Furthermore, the proposed protocols have the advantages of reduced communication costs and controller-updating costs. Simulation examples are given to illustrate the proposed theoretical results.

  2. 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

  3. Prefrontal activity during response inhibition decreases over time in the postpartum period.

    PubMed

    Bannbers, Elin; Gingnell, Malin; Engman, Jonas; Morell, Arvid; Sylvén, Sara; Skalkidou, Alkistis; Kask, Kristiina; Bäckström, Torbjörn; Wikström, Johan; Poromaa, Inger Sundström

    2013-03-15

    The postpartum period is characterized by complex hormonal changes, but human imaging studies in the postpartum period have thus far predominantly focused on the neural correlates of maternal behavior or postpartum depression, whereas longitudinal studies on neural correlates of cognitive function across the postpartum period in healthy women are lacking. The aim of this study was to longitudinally examine response inhibition, as a measure of executive function, during the postpartum period and its neural correlates in healthy postpartum women and non-postpartum controls. Thirteen healthy postpartum women underwent event-related functional magnetic resonance imaging while performing a Go/NoGo task. The first assessment was made within 48 h of delivery, and the second at 4-7 weeks postpartum. In addition, 13 healthy women examined twice during the menstrual cycle were included as non-postpartum controls. In postpartum women region of interest analyses revealed task-related decreased activations in the right inferior frontal gyrus, right anterior cingulate, and bilateral precentral gyri at the late postpartum assessment. Generally, postpartum women displayed lower activity during response inhibition in the bilateral inferior frontal gyri and precentral gyri compared to non-postpartum controls. No differences in performance on the Go/NoGo task were found between time-points or between groups. In conclusion, this study has discovered that brain activity in prefrontal areas during a response inhibition task decreases throughout the course of the first postpartum weeks and is lower than in non-postpartum controls. Further studies on the normal adaptive brain activity changes that occur during the postpartum period are warranted.

  4. 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.

  5. 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.

  6. Master equation approach to time-dependent escape rate over a periodically oscillating barrier.

    PubMed

    Wang, Xin-Xin; Bao, Jing-Dong

    2011-01-01

    We propose a master equation approach to investigate the transition function and the escape dynamics of a general damping particle in a metastable potential. The transition function in the master equation is obtained analytically from the Langevin dynamics. We apply it to the oscillating barrier problem, in which the potential is structured by a harmonic potential smoothly linking with an inverse harmonic one, and thus both the barrier height and the curvature of potential change periodically with time. We use a Monte Carlo method to simulate the master equation and then calculate a time-dependent escape rate. This can decrease the coarse grain and save more computing time in comparison with the Langevin simulation. Our result has shown that there is a resonant activation phenomenon for the escape rate in the underdamped case.

  7. Dynamical systems analysis of fluid transport in time-periodic vortex ring flows

    NASA Astrophysics Data System (ADS)

    Shariff, Karim; Leonard, Anthony; Ferziger, Joel H.

    2006-04-01

    It is known that the stable and unstable manifolds of dynamical systems theory provide a powerful tool for understanding Lagrangian aspects of time-periodic flows. In this work we consider two time-periodic vortex ring flows. The first is a vortex ring with an elliptical core. The manifolds provide information about entrainment and detrainment of irrotational fluid into and out of the volume transported with the ring. The likeness of the manifolds with features observed in flow visualization experiments of turbulent vortex rings suggests that a similar process might be at play. However, what precise modes of unsteadiness are responsible for stirring in a turbulent vortex ring is left as an open question. The second situation is that of two leapfrogging rings. The unstable manifold shows striking agreement with even the fine features of smoke visualization photographs, suggesting that fluid elements in the vicinity of the manifold are drawn out along it and begin to reveal its structure. We suggest that interpretations of these photographs that argue for complex vorticity dynamics ought to be reconsidered. Recently, theoretical and computational tools have been developed to locate structures analogous to stable and unstable manifolds in aperiodic, or finite-time systems. The usefulness of these analogs is demonstrated, using vortex ring flows as an example, in the paper by Shadden, Dabiri, and Marsden [Phys. Fluids 18, 047105 (2006)].

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

    DOE PAGES

    Charalampidis, E. G.; Li, F.; Chong, C.; ...

    2015-01-01

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

  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. 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

  11. The method of calculating forced oscillations in nonlinear discrete-time systems under periodic external actions

    NASA Astrophysics Data System (ADS)

    Bryuhanov, Yu. A.

    2010-08-01

    We consider a method for calculating forced oscillations in nonlinear discrete-time systems under periodic external actions. The method is based on representing the stationary oscillations in the form of an invariant set of nonlinear discrete point mappings and allows one to calculate the nonlinear-system response in the steady-state regime. The examples of using this method for calculating forced oscillations in the first- and second-order nonlinear recursive systems under the harmonic-signal action on such systems are presented.

  12. 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.

  13. Time Periodic Electro-Osmotic-Flow of Jeffrey Fluid in a Circular Microtube

    NASA Astrophysics Data System (ADS)

    Jian, Y. J.; Liu, Q. S.; Duan, H. Z.; Chang, L.; Yang, L. G.

    2011-09-01

    Flow behavior of time periodic electro-osmotic flow (EOF) of non-Newtonian (Jeffrey) fluids in a circular microtube is investigated based on a linearized Poisson-Boltzmann equation, together with the Cauchy momentum equation and the Jeffrey constitutive equation. Taking near-wall depletion effects of macromolecules into account, we divided the flow region into skimming layer and the bulk. Analytical solutions of EOF velocity distribution are obtained. By numerical computations, the influences of the related parameters on the velocity amplitude are studied.

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

    PubMed

    Park, Sohyun; 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.

  15. 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.

  16. The 18.6-year lunar nodal cycle and surface temperature variability in the northeast Pacific

    NASA Astrophysics Data System (ADS)

    McKinnell, Stewart M.; Crawford, William R.

    2007-02-01

    The 18.6-year lunar nodal cycle (LNC) is a significant feature of winter (January) air and sea temperatures along the North American west coast over a 400-year period. Yet much of the recent temperature variation can also be explained by wind patterns associated with the PNA teleconnection. At Sitka, Alaska, (57°N) and nearby stations in northern British Columbia, the January PNA index accounts for over 70% of average January air temperatures in lengthy meteorological records. It appears that the LNC signal in January air temperatures in this region is not independent of the PNA, but is a component of it. The Sitka air temperature record, along with SSTs along the British Columbia coast and the PNA index have significant cross-correlations with the LNC that appear at a 2-year lag, LNC leading. The influence of the PNA pattern declines in winter with decreasing latitude but the LNC component does not. It appears as a significant feature of long-term SST variation at Scripps Pier and the California Current System. The LNC also appears over centennial-scales in proxy temperatures along western North America. The linkage of LNC-moderated surface temperatures to processes involving basin-scale teleconnections expands the possibility that the proximate mechanism may be located remotely from its expression in the northeast Pacific. Some of the largest potential sources of a diurnal tidal signal in the atmosphere are located in the western Pacific; the Sea of Okhotsk and the Indonesian archipelago.

  17. 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.

  18. Space-time Cooperative Symmetry in a Periodically Driven Tight Binding Model

    NASA Astrophysics Data System (ADS)

    Inoue, Jun-ichi

    2017-02-01

    In recent extensive studies of emergent phenomena in solid-state and cold atomic systems, alteration of the symmetry inherent to a given system by applying an external time-dependent field is a central issue. We have found that how the time reversal symmetry is broken is not solely determined by temporal aspects, but also committed to spatial symmetry of the system. This connection between spatial and temporal symmetries induces various interesting phenomena that have not yet been discussed. This work reports one of these: symmetry-protected band sticking together in an effective-energy band structure of periodically driven electron systems. Experiments that could be used to observe the effect are discussed. The findings reported herein will contribute to a deeper understanding of the underlying physics and guiding principles of Floquet engineering.

  19. The effects of time-periodic shear on a diffusion flame anchored to a propellant

    SciTech Connect

    Buckmaster, J.; Jackson, T.L.

    2000-01-01

    The authors examine a single diffusion flame anchored to 1/4-spaces of solid fuel and oxidizer, a configuration relevant to the combustion of heterogeneous solid propellants. A time-periodic shear flow is applied, to model the shear that can be generated by the interaction of acoustic waves and the rotational base flow in a rocket chamber. The response of the flame to this shear, the heat flux to the surface, etc., are calculated numerically. Significant enhancement of the maximum temperature and the time-averaged total heat flux to the surface re found. These enhancements are essentially maximized at zero frequency, and at low frequencies the response depends critically on the instantaneous direction of the shear.

  20. Detection of periodic signal of arbitrary shape with random time delay

    NASA Astrophysics Data System (ADS)

    Ansari, K. A.

    1985-06-01

    The detection of periodic signals of arbitrary wave shape with random time delay in additive white Gaussian noise, is a problem of practical significance in radar and communication applications. In this thesis, the analysis and design of optimum and suboptimum receivers for detecting signals as described above has been carried out. The design of optimum (in minimum probability of error, Pe sense) receivers is based on the likelihood ratio test under the assumption of low SNR conditions. The design of suboptimum receivers is based on the heuristic approaches that intuitively yield reasonably good performance. Examples have been analyzed in order to present numerical results in graphical form on the performance of the receivers under different assumptions of wave ships and p.d.f. on the random time delay associated with the signal.

  1. On Bifurcating Time-Periodic Flow of a Navier-Stokes Liquid Past a Cylinder

    NASA Astrophysics Data System (ADS)

    Galdi, Giovanni P.

    2016-10-01

    We provide general sufficient conditions for the existence and uniqueness of branching out of a time-periodic family of solutions from steady-state solutions to the two-dimensional Navier-Stokes equations in the exterior of a cylinder. By separating the time-independent averaged component of the velocity field from its oscillatory one, we show that the problem can be formulated as a coupled elliptic-parabolic nonlinear system in appropriate and distinct function spaces, with the property that the relevant linearized operators become Fredholm of index 0. In this functional setting, the notorious difficulty of 0 being in the essential spectrum entirely disappears and, in fact, it is even meaningless. Our approach is different and, we believe, more natural and simpler than those proposed by previous authors discussing similar questions. Moreover, the latter all fail, when applied to the problem studied here.

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

    PubMed

    Taylor, Graham K; Zbikowski, Rafał

    2005-06-22

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

  3. Effect of fluconazole on viability of Candida albicans over extended periods of time.

    PubMed Central

    Sohnle, P G; Hahn, B L; Erdmann, M D

    1996-01-01

    The treatment of chronic mycoses may expose the infecting organisms to antimicrobial agents for extended periods of time. It is possible that an azole antifungal drug such as fluconazole, with primarily fungistatic activity in standard in vitro susceptibility tests, might be able to damage the fungal cells and reduce their viability over prolonged incubations under nonproliferating conditions. To test this possibility, Candida albicans yeast cells were exposed to various concentrations of fluconazole in RPMI 1640 tissue culture medium for 4 h at 37 degrees C, washed free of the drug, and then incubated at 37 degrees C for a 28-day period; enumeration of the remaining CFU at various times during this period revealed no increased loss of viability for the fluconazole-exposed organisms. However, when fluconazole was added to the organisms maintained in distilled water (with or without pretreatment with the drug), a marked reduction of viability was found. At 14 days of incubation with two strains of C. albicans, negative cultures were found for 7 of 10 and 10 of 11 samples, respectively, containing 1.0 microgram of fluconazole per ml versus 0 of 10 and 1 of 11 control samples (P of < 0.01 and 0.001, respectively). The effect of fluconazole on fungal viability under these conditions became noticeable at approximately 7 days and was greater when the samples were incubated at 37 degrees C rather than 25 degrees C. These findings suggest that fluconazole may have fungicidal effects on fungal cells during prolonged exposures under conditions in which the organisms are prevented from proliferating by lack of nutrients. PMID:8913476

  4. 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

  5. Ewing Sarcoma of the Bone in Children under 6 Years of Age

    PubMed Central

    De Ioris, Maria Antonietta; Prete, Arcangelo; Cozza, Raffaele; Podda, Marta; Manzitti, Carla; Pession, Andrea; Schiavello, Elisabetta; Contoli, Benedetta; Balter, Rita; Fagioli, Franca; Bisogno, Gianni; Amoroso, Loredana

    2013-01-01

    Background Ewing Sarcoma Family Tumours (ESFT) are rare in early childhood. The aim of this study was to report the clinical characteristics and outcome of children under 6 years of age affected by ESFT of the bone in Italy. Methods The records of all the children diagnosed with osseous ESFT in centres members of the Associazione Italiana di Ematologia ed Oncologia Pediatrica (AIEOP) from 1990 to 2008 were reviewed. The Kaplan–Meier method was used for estimating overall and progression-free survival (OS, PFS) curves; multivariate analyses were performed using Cox proportional hazards regression model. Results This study includes 62 patients. An axial primary localization was present in 66% of patients, with the primary site in the chest wall in 34%. Fourteen (23%) patients presented metastatic disease. The 5-year OS and PFS were 73% (95% confidence interval, CI, 58–83%) and 72% (95% CI 57–83%) for patients with localized disease and 38% (95% CI 17–60%) and 21% (95% CI 5–45%) for patients with metastatic disease. Metastatic spread, skull/pelvis/spine primary localization, progression during treatment and no surgery predicted worse survival (P<0.01), while patients treated in the last decade had better survival (P  = 0.002). In fact, the 5-year OS and PFS for patients diagnosed in the period 2000–2008 were 89% (95% CI 71–96%) and 86% (95% CI 66–94%), respectively. Conclusion The axial localization is the most common site of ESFT in pre-scholar children. Patients treated in the most recent period have an excellent outcome. PMID:23382839

  6. Observations and predictions of eclipse times by astronomers in the pre-telescopic period.

    NASA Astrophysics Data System (ADS)

    Steele, J. M.

    Eclipses of the Sun and Moon are among the most impressive of celestial events. It is therefore unsurprising that they have played an important role in the astronomy and astrology of most early cultures. Many hundreds of references to eclipses are found in the writings of the chroniclers and astronomers of the pre-telescopic world. In particular, the astronomers of Babylon, Ancient Greece, the Islamic Near East. Later Medieval and Renaissance Europe, China, and Japan, recorded a large number of observations and predictions of the time of an eclipse. The present study contains an extensive compilation of all known timed reports of eclipse observations and predictions made by astronomers in the pre-telescopic period. By performing a basic analysis of the recorded times, it has been possible to trace the gradual development of the techniques used by the astronomers to observe and predict eclipses. In order to conduct this analysis, it has been necessary to investigate a number of other problems including the dating of damaged observational accounts, the units of time used by the early astronomers, and the methods by which the Babylonians predicted eclipses. Many of these questions have not previously been answered. Therefore, the results of this study provide important information regarding the astronomies of these early cultures.

  7. 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

  8. 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.

  9. Pulse propagation through a slab with time-periodic dielectric function ε(t).

    PubMed

    Zurita-Sánchez, Jorge R; Abundis-Patiño, J H; Halevi, P

    2012-02-27

    We describe pulse propagation through a slab with periodic dielectric function ε(t), thus extending our previous investigation for monochromatic incidence [Phys. Rev. A 79, 053821 (2009)]. Based on the concepts of phase and group delays, we prove that, for an incident quasi-monochromatic pulse, the transmitted pulse can be expressed as a superposition of partial pulses that are exact replicas of the incident pulse and that exit the slab with a time delay. These partial pulses have harmonic carrier frequencies ω c - nΩ (n is an integer, ω c is the carrier frequency of the incident pulse, and Ω = 2π/T is the slab modulation frequency). We find numerically that these partial pulses can be fast (peak velocity vn > c or vn < 0) or slow (vn < c). Further, we investigate the peak velocity v p of the outcoming pulse for several cases. We find that this peak velocity v p and the partial peak velocities vn do not diverge--as occurs to the group velocity v g of the bulk dynamic-periodic medium when ω c = Ω/2. We expect that these results could be verified in the microwave regime [see Halevi et al., Proc. SPIE 8095, 80950I (2011)].

  10. 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.

  11. 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.

  12. 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.

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

    PubMed

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

    2015-11-06

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

  14. Predicting sleep apnoea syndrome from heart period: a time-frequency wavelet analysis.

    PubMed

    Roche, F; Pichot, V; Sforza, E; Court-Fortune, I; Duverney, D; Costes, F; Garet, M; Barthélémy, J C

    2003-12-01

    Heart rate fluctuations are a typical finding during obstructive sleep apnoea, characterised by bradycardia during the apnoeic phase and tachycardia at the restoration of ventilation. In this study, a time-frequency domain analysis of the nocturnal heart rate variability (HRV) was evaluated as the single diagnostic marker for obstructive sleep apnoea syndrome (OSAS). The predictive accuracy of time-frequency HRV variables (wavelet (Wv) decomposition parameters from level 2 (Wv2) to level 256 (Wv256)) obtained from nocturnal electrocardiogram Holter monitoring were analysed in 147 consecutive patients aged 53.8+/-11.2 yrs referred for possible OSAS. OSAS was diagnosed in 66 patients (44.9%) according to an apnoea/hypopnoea index > or = 10. Using receiver-operating characteristic curves analysis, the most powerful predictor variable was Wv32 (W 0.758, p<0.0001), followed by Wv16 (W 0.729, p<0.0001) and Wv64 (W 0.700, p<0.0001). Classification and Regression Trees methodology generated a decision tree for OSAS prediction including all levels of Wv coefficients, from Wv2 to Wv256 with a sensitivity reaching 92.4% and a specificity of 90.1% (percentage of agreement 91.2%) with this nonparametric analysis. Time-frequency parameters calculated using wavelet transform and extracted from the nocturnal heart period analysis appeared as powerful tools for obstructive sleep apnoea syndrome diagnosis.

  15. 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.

  16. Caenorhabditis elegans period homolog lin-42 regulates the timing of heterochronic miRNA expression.

    PubMed

    McCulloch, Katherine A; Rougvie, Ann E

    2014-10-28

    MicroRNAs (miRNAs) are small RNAs that regulate gene expression posttranscriptionally via the 3' UTR of target mRNAs and were first identified in the Caenorhabditis elegans heterochronic pathway. miRNAs have since been found in many organisms and have broad functions, including control of differentiation and pluripotency in humans. lin-4 and let-7-family miRNAs regulate developmental timing in C. elegans, and their proper temporal expression ensures cell lineage patterns are correctly timed and sequentially executed. Although much is known about miRNA biogenesis, less is understood about how miRNA expression is timed and regulated. lin-42, the worm homolog of the circadian rhythm gene period of flies and mammals, is another core component of the heterochronic gene pathway. lin-42 mutants have a precocious phenotype, in which later-stage programs are executed too early, but the placement of lin-42 in the timing pathway is unclear. Here, we demonstrate that lin-42 negatively regulates heterochronic miRNA transcription. let-7 and the related miRNA miR-48 accumulate precociously in lin-42 mutants. This defect reflects transcriptional misregulation because enhanced expression of both primary miRNA transcripts (pri-miRNAs) and a let-7 promoter::gfp fusion are observed. The pri-miRNA levels oscillate during larval development, in a pattern reminiscent of lin-42 expression. Importantly, we show that lin-42 is not required for this cycling; instead, peak amplitude is increased. Genetic analyses further confirm that lin-42 acts through let-7 family miRNAs. Taken together, these data show that a key function of lin-42 in developmental timing is to dampen pri-miRNAs levels, preventing their premature expression as mature miRNAs.

  17. 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.

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  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. H2 control of discrete-time periodic systems with Markovian jumps and multiplicative noise

    NASA Astrophysics Data System (ADS)

    Ma, Hongji; Jia, Yingmin

    2013-10-01

    This paper addresses the problem of optimal and robust H2 control for discrete-time periodic systems with Markov jump parameters and multiplicative noise. To analyse the system performance in the presence of exogenous random disturbance, an H2 norm is firstly established on the basis of Gramian matrices. Further, under the condition of exact observability, a necessary and sufficient condition is presented for the solvability of H2 optimal control problem by means of a generalised Riccati equation. When the transition probabilities of jump parameter are incompletely measurable, an H2-guaranteed cost norm is exploited and the robust H2 controller is designed through a linear matrix inequality (LMI) optimisation approach. An example of a networked control system is supplied to illustrate the proposed results.

  4. 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.

  5. 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.

  6. Crossing rule for a PT-symmetric two-level time-periodic system

    SciTech Connect

    Moiseyev, Nimrod

    2011-05-15

    For a two-level system in a time-periodic field we show that in the non-Hermitian PT case the level crossing is of two quasistationary states that have the same dynamical symmetry property. At the field's parameters where the two levels which have the same dynamical symmetry cross, the corresponding quasienergy states coalesce and a self-orthogonal state is obtained. This situation is very different from the Hermitian case where a crossing of two quasienergy levels happens only when the corresponding two quasistationary states have different dynamical symmetry properties and, unlike the situation in the non-Hermitian case, the spectrum remains complete also when the two levels cross.

  7. Atmospheric CO2 and climate on millennial time scales during the last glacial period.

    PubMed

    Ahn, Jinho; Brook, Edward J

    2008-10-03

    Reconstructions of ancient atmospheric carbon dioxide (CO2) variations help us better understand how the global carbon cycle and climate are linked. We compared CO2 variations on millennial time scales between 20,000 and 90,000 years ago with an Antarctic temperature proxy and records of abrupt climate change in the Northern Hemisphere. CO2 concentration and Antarctic temperature were positively correlated over millennial-scale climate cycles, implying a strong connection to Southern Ocean processes. Evidence from marine sediment proxies indicates that CO2 concentration rose most rapidly when North Atlantic Deep Water shoaled and stratification in the Southern Ocean was reduced. These increases in CO2 concentration occurred during stadial (cold) periods in the Northern Hemisphere, several thousand years before abrupt warming events in Greenland.

  8. Ordering of small particles in one-dimensional coherent structures by time-periodic flows.

    PubMed

    Pushkin, D O; Melnikov, D E; Shevtsova, V M

    2011-06-10

    Small particles transported by a fluid medium do not necessarily have to follow the flow. We show that for a wide class of time-periodic incompressible flows inertial particles have a tendency to spontaneously align in one-dimensional dynamic coherent structures. This effect may take place for particles so small that often they would be expected to behave as passive tracers and be used in PIV measurement technique. We link the particle tendency to form one-dimensional structures to the nonlinear phenomenon of phase locking. We propose that this general mechanism is, in particular, responsible for the enigmatic formation of the "particle accumulation structures" discovered experimentally in thermocapillary flows more than a decade ago and unexplained until now.

  9. 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.

  10. Behaviour of a thermodynamic model system under time-dependent periodic boundary conditions

    NASA Astrophysics Data System (ADS)

    Berry, R. S.; Disep, F.; Sertorio, L.

    1982-06-01

    A system made of several components is examined which maintains a given volume at a constant temperature Tb or at an almost constant Tb(t), such as in thermal engines. A finite domain D2 is enveloped by a finite domain D1, which is in contact with two thermal baths with time-dependent periodic temperatures Ts(t) and Te(t). The best way to make T2, the temperature field belonging to D2, as close as possible to a predetermine constant is determined using the insertion of controlled energy sources or sinks. The formal approach with zero energy expenditure and the maximization problem are considered. The concepts and properties of free boundary control and deterministic boundary control are examined.

  11. 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.

  12. 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

  13. 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…

  14. 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.

  15. 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

  16. 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.

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

    PubMed

    Kivelä, Mikko; Porter, Mason A

    2015-11-01

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

  18. Nutritional intervention on malnutrition in 3-6 years old rural children in Qazvin Province, Iran.

    PubMed

    Zavoshy, R; Noroozi, M; Jahanihashemi, H; Kiamiri, D

    2012-04-01

    Malnutrition is one of the major causes of mortality and morbidity in children. Not only include acute effects on children's health, but also it has long-term effects on their cognitive development and economic growth in the society. Wasting (weight for height with Z<-1) is one of the malnutrition indices in children. The aim of this study was to determine the effect of a cooked meal for 175 days on the anthropometric indices of weight, height and weight for height (wasting) of 3-6 years old children in all the rural nursery of Qazvin province, in Iran. In this interventional study, 2385 children (48.8% female and 51.2% male) were recruited. Data were collected by a census in 2010. The children were received a cooked meal based on 360 +/- 20 kcal energy, 17% protein, 53% carbohydrate and 30% fat per day for 175 days at lunch time. The anthropometric indices were collected before and after the intervention. The results were analyzed using paired t-test by SPSS V.16 software. Prevalence of wasting (mild and moderate) and (sever malnutrition) after intervention reduced from 14.2 and 0.95-12.6 and 0.5%, respectively (p < 0.05). Receiving a cooked meal significantly decreased wasting (15.2-13.2%) in all children (p < 0.05). Nutritional intervention with cooked meal for 175 days had significant reduction in wasting in all children.

  19. The Student-Authored Biomedical Publications at Alfaisal University, Saudi Arabia: a 6-year descriptive analysis.

    PubMed

    Alnajjar, Asma; Khan, Tehreem A; Mina, Syeda; Alkattan, Khaled; Abu-Zaid, Ahmed

    2015-01-01

    There are limited numbers of studies which comprehensively explored the research publications authored by medical students. To descriptively analyze the student-authored research publications originating from Alfaisal University-College of Medicine (Riyadh, Saudi Arabia) over a 6-year period. All student-authored research publications were retrieved from PubMed(®) and the College's publication database. Study inclusion criteria included: (1) at least one medical student author, (2) published and/or accepted in-press PubMed-indexed article from 10 September 2008 to 31 December 2014. Data was transferred to Microsoft Excel Software for descriptive statistical analysis of variable parameters. Seventy-three (n = 73) articles met the study inclusion criteria. They were published by 170 students; the majority were males (79.4 %) and clerkship students (65.9 %). There was a markedly steady increase in number of yearly publications from 1 publication in 2009 to 35 publications by the end of 2014. Fifty (68.5 %), twenty-nine (39.7 %) and thirty-seven (50.7 %) students were first, second and corresponding authors, respectively. The most frequent research areas were clinical science (43.8 %), basic science (23.3 %) and medical education (21.9 %). The most frequent research types were case reports (41.1 %), research articles (32.9 %) and correspondence letters (15.1 %). Fifty-seven (78.1 %) and sixteen (21.9 %) publications took place in local and abroad institutes, respectively. Most publications (71.2 %) had impact factors below 2. The mean ± SD of articles' impact factors and citations were 3.9 ± 9.9 and 1.9 ± 4.1, respectively. Students demonstrated positive attitudes towards publishing and significantly contributed to the institution's pool of research publications.

  20. Tuberculosis drug-resistance in Lisbon, Portugal: a 6-year overview.

    PubMed

    Perdigão, J; Macedo, R; Silva, C; Pinto, C; Furtado, C; Brum, L; Portugal, I

    2011-09-01

    Multidrug-resistance and extensive drug-resistance pose a serious threat to tuberculosis management in Portugal. The country has high TB incidence rates in comparison with other European Union countries, with the Lisbon Health Region being one of the most affected. In the present study we have analysed a convenience sample of 3025 Mycobacterium tuberculosis clinical isolates, recovered over a 6-year period (2001-2006) in the Lisbon Health Region, regarding drug-resistance both to first-line and second-line drugs. Moreover, 100 of these isolates were also genotyped by 12-loci Mycobacterial Interspersed Repetitive Unit - Variable Number of Tandem Repeats (MIRU-VNTR) analysis. We have compared each year and observed the existence of 22 different resistance profiles, with MDR-TB rates ranging between 9.9% and 15.2% and XDR-TB rates, relative to the number of MDR-TB isolates, between 44.3% and 66.1% (excluding 1 year here considered as an outlier). A steady increase in the fraction of MDR-TB isolates resistant to all first-line drugs was also noticed. The genotyping analysis of MDR-TB isolates revealed six clusters, of which three (Lisboa3, Lisboa4 and Q1) were related to XDR-TB. Our results show that active transmission of MDR- and XDR-TB is taking place and that the high prevalence of observed XDR-TB is due to the continued transmission of particular genetic clusters. Enforcement of the implementation of genotyping in diagnostic routines would lead to early detection of resistant cases.

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

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

    Photodeposition of metallic nanostructures onto ferroelectric surfaces, which have been chemically patterned using a proton exchange process, has recently been demonstrated. By varying the molar concentration of the AgNO3 solution and the illumination time, one can determine the initial nucleation sites, control the rate of nucleation and the height of silver nanostructures formed, and study the mechanisms by which these processes occurs. The nanoparticles are found to deposit preferentially in the boundary between ferroelectric and proton exchanged regions, in an area proton exchanged via lateral diffusion under the masking layer used for chemical patterning, consistent with our previous results. Using a short illumination time (3 min), we are able to determine that the initial nucleation of the silver nanostructure, having a width of 0.17 ± 0.02 μm and a height of 1.61 ± 0.98 nm, occurs near the edge of the reactive ion etched area within this lateral diffusion region. Over longer illumination times (15 min), we find that the silver deposition has spread to a width of 1.29 ± 0.06 μm, extending across the entire lateral diffusion region. We report that at a high molar concentration of AgNO3 (10-2 M), the amount of silver deposition for 5 min UV illumination is greater (2.88 ± 0.58 nm) compared to that at low (10-4 M) concentrations (0.78 ± 0.35 nm), however, this is not the case for longer time periods. With increasing illumination time (15 min), experiments at 10-4 M had greater overall deposition, 6.90 ± 1.52 nm, compared to 4.50 ± 0.76 nm at 10-2 M. For longer exposure times (30 min) at 10-2 M, the nanostructure height is 4.72 ± 0.59 nm, suggesting a saturation in the nanostructure height. The results are discussed in terms of the electric double layer that forms at the crystal surface. There is an order of magnitude difference between the Debye lengths for 10-2 and 10-4 M solutions, i.e., 3.04 vs. 30.40 nm, which suggests the Debye length plays a

  2. Peri-implant bone tissues around retrieved human implants after time periods longer than 5 years: a retrospective histologic and histomorphometric evaluation of 8 cases.

    PubMed

    Iezzi, Giovanna; Piattelli, Adriano; Mangano, Carlo; Shibli, Jamil A; Vantaggiato, Giovanni; Frosecchi, Massimo; Di Chiara, Claudio; Perrotti, Vittoria

    2014-01-01

    Only rarely, it is possible to find in the literature histological reports of human retrieved implants, especially after several years of functional loading. These implants can help us in understanding the reactions of peri-implant bone. The aim of this study was to perform a histologic and histomorphometric analysis of the peri-implant tissues behavior and of the bone-titanium interface in titanium dental implants retrieved from patients after time periods longer than 5 years. The archives of the Implant Retrieval Center of the Dental School of the University of Chieti-Pescara, Italy were searched for human dental implants, retrieved after a loading period of more than 5 years. A total of 8 implants were found: 3 of these had been retrieved after 5 years, 1 after 6 years, one after 10 years, 1 after 14 years, 1 after 18 years, 1 after 22 years. Only the bone to implant contact in the three best threads was evaluated. Compact, mature, lamellar bone, with few and small marrow spaces, was present around the implants. Osteons with Haversian canals were present inside some threads, in close proximity to the interface, at both cortical and trabecular regions. Other osteons had a direction perpendicular to the direction of the long axis of the implants. Numerous reversal lines were present. At higher magnification, no gaps or fibrous, connective tissues were present at the interface. The BIC of the three best threads for all implants varied from 94 to 100 %.In conclusion, within the limitations of the present report histology showed that implants with different surfaces all presented the potential to maintain osseointegration over a long period, with a continuous remodeling at the interface, as indicated by the presence of reversal lines.

  3. 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).

  4. A Developmental Sensitive Period for Spike Timing-Dependent Plasticity in the Retinotectal Projection

    PubMed Central

    Tsui, Jennifer; Schwartz, Neil; Ruthazer, Edward S.

    2010-01-01

    The retinotectal projection in Xenopus laevis has been shown to exhibit correlation-based refinement of both anatomical and functional connectivity during development. Spike timing-dependent plasticity (STDP) is an appealing experimental model for correlation-based synaptic plasticity because, in contrast to plasticity induction paradigms using tetanic stimulation or sustained postsynaptic depolarization, its induction protocol more closely resembles natural physiological activity. In Xenopus tadpoles, where anatomical remodeling has been reported throughout much of the life of the animal, in vivo retinotectal STDP has only been examined under a limited set of experimental conditions. Using perforated-patch recordings of retina-evoked EPSCs in tectal neurons, we confirmed that repeatedly driving a retinotectal EPSP 5–10 ms prior to inducing an action potential in the postsynaptic cell, reliably produced timing-dependent long-term potentiation (t-LTP) of the retinotectal synapse in young wild type tadpoles (stages 41–44). At these stages, retinotectal timing-dependent long-term depression (t-LTD) also could be induced by evoking an EPSP to arrive 5–10 ms after an action potential in the tectal cell. However, retinotectal STDP using this standard protocol was limited to a developmental sensitive period, as we were unable to induce t-LTP or t-LTD after stage 44. Surprisingly, this STDP protocol also failed to induce reliable STDP in albino tadpoles at the early ages when it was effective in wild type pigmented animals. Nonetheless, low-frequency flashes to the eye produced a robust NMDA receptor-dependent retinotectal LTD in stage 47 albino tadpoles, demonstrating that the retinotectal synapse can nonetheless be modified in these animals using different plasticity paradigms. PMID:21423499

  5. 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

  6. 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

  7. Recent improvement in lung cancer screening: a comparison of the results carried out in two different time periods.

    PubMed

    Kitajima, Takuji; Nishii, Kenji; Ueoka, Hiroshi; Shibayama, Takuo; Gemba, Kenichi; Kodani, Tsuyoshi; Kiura, Katsuyuki; Tabata, Masahiro; Hotta, Katsuyuki; Tanimoto, Mitsune; Sobue, Tomotaka

    2006-06-01

    To evaluate recent improvements in lung cancer screening, we compared the results of recently conducted lung cancer screening with those of a previous screening. This study compared the survival of lung cancer patients detected by lung cancer screening conducted between 1976 and 1984 (early period) with that conducted between 1989 and 1997 (late period). Two hundred seventy-six patients with lung cancer were detected in the early period and 541 patients with lung cancer were detected in the late period. The median survival time (late : 49.8 vs. early : 27.8 months) and the 5-year survival rate (late : 47.8 vs. early : 34.8%) of the patients with lung cancer detected in the late period were significantly better than those in the early period (p = 0.0054). Among patients undergoing resection, the proportion of pathological stage I patients in the late period was significantly higher than that in the early period (late : 60.8 vs. early : 54.9%, p = 0.005). Multivariate analysis showed that the screening time period was a significant prognostic factor (hazard ratio = 0.685, 95% confidence interval : 0.563-0.832, p = 0.0002). These results were consistent with the findings of case-control studies of lung cancer screening programs in the late period recently conducted in Japan, which also showed a greater efficacy for screening than for previous case-control studies in the early period.

  8. 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

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  10. Transient time period analysis of smooth handoffs in mobile IP networks and its application to media streaming

    NASA Astrophysics Data System (ADS)

    Lee, Dongwook; Kim, JongWon

    2003-11-01

    Streaming media applications over mobile IP networks suffer from playback disruptions resulting from handoff blackout period as well as bandwidth fluctuation. To overcome buffer shortage, pre-buffering technique can be adopted where the client stores sufficient amount of stream in advance. However, under the mobile IP handoff that may take up to several seconds, it is extremely difficult to sustain seamless playback. Inaccurate and conservative choice on the required buffering size can waste limited latency budget, resulting in quality degradation. In this paper, we are extending--from smooth handoff to fast handoff of mobile IPv6--the transient time analysis recently proposed to approximate transient time durations, STP (silent time period) and UTP (unstable time period). The approximated time periods are utilized to estimate the required buffering buffer size accurately. Network simulation result evaluted under simplified buffering strategies shows that the proposed scheme can provide appropriate guideline on the buffer parameters and thus can improve seamless streaming.

  11. The circadian clock has transient plasticity of period and is required for timing of nocturnal processes in Arabidopsis.

    PubMed

    Dodd, Antony N; Dalchau, Neil; Gardner, Michael J; Baek, Seong-Jin; Webb, Alex A R

    2014-01-01

    A circadian rhythm matched to the phase and period of the day-night cycle has measurable benefits for land plants. We assessed the contribution of circadian period to the phasing of cellular events with the light : dark cycle. We also investigated the plasticity of circadian period within the Arabidopsis circadian oscillator. We monitored the circadian oscillator in wild-type and circadian period mutants under light : dark cycles of varying total duration. We also investigated changes in oscillator dynamics during and after the transition from light : dark cycles to free running conditions. Under light : dark cycles, dawn and dusk were anticipated differently when the circadian period was not resonant with the environmental period ('T cycle'). Entrainment to T cycles differing from the free-running period caused a short-term alteration in oscillator period. The transient plasticity of period was described by existing mathematical models of the Arabidopsis circadian network. We conclude that a circadian period resonant with the period of the environment is particularly important for anticipation of dawn and the timing of nocturnal events; and there is short-term and transient plasticity of period of the Arabidopsis circadian network.

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

    SciTech Connect

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

    1991-04-10

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

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-01-01

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

  15. 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.

  16. A simple derivation for amplitude and time period of charged particles in an electrostatic bathtub potential

    NASA Astrophysics Data System (ADS)

    Prathap Reddy, K.

    2016-11-01

    An ‘electrostatic bathtub potential’ is defined and analytical expressions for the time period and amplitude of charged particles in this potential are obtained and compared with simulations. These kinds of potentials are encountered in linear electrostatic ion traps, where the potential along the axis appears like a bathtub. Ion traps are used in basic physics research and mass spectrometry to store ions; these stored ions make oscillatory motion within the confined volume of the trap. Usually these traps are designed and studied using ion optical software, but in this work the bathtub potential is reproduced by making two simple modifications to the harmonic oscillator potential. The addition of a linear ‘k 1|x|’ potential makes the simple harmonic potential curve steeper with a sharper turn at the origin, while the introduction of a finite-length zero potential region at the centre reproduces the flat region of the bathtub curve. This whole exercise of modelling a practical experimental situation in terms of a well-known simple physics problem may generate interest among readers.

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

    PubMed

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

    1987-06-19

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

  18. Real-time analysis of arc-induced Long Period Gratings under gamma irradiation

    PubMed Central

    Esposito, Flavio; Ranjan, Rajeev; Stăncălie, Andrei; Sporea, Dan; Neguţ, Daniel; Becherescu, Nicu; Campopiano, Stefania; Iadicicco, Agostino

    2017-01-01

    In this paper, we present a comparative experimental and theoretical study on gamma radiation sensitivity of Long Period Gratings (LPGs), fabricated by electric arc discharge technique, as monitored in three single mode optical fibers supplied by different manufacturers. A real-time measurement of LPGs’ wavelength shift was performed until a total dose of 35 kGy was reached, with average dose rate of 0.18 kGy/h, the irradiation being done at room temperature. In one case, a maximum radiation sensitivity of 1.34 nm/kGy was recorded for doses up to 0.5 kGy. Moreover, by combining experimental results with numerical simulations, it was found that changes occurred in the core refractive index of the irradiated optical fibers up to 2.5 ∙ 10−5. The increase of the core thermo-optic coefficient up to 1.5 ∙ 10−8/°C was observed as well. PMID:28262784

  19. 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.

  20. Real-time analysis of arc-induced Long Period Gratings under gamma irradiation

    NASA Astrophysics Data System (ADS)

    Esposito, Flavio; Ranjan, Rajeev; Stăncălie, Andrei; Sporea, Dan; Neguţ, Daniel; Becherescu, Nicu; Campopiano, Stefania; Iadicicco, Agostino

    2017-03-01

    In this paper, we present a comparative experimental and theoretical study on gamma radiation sensitivity of Long Period Gratings (LPGs), fabricated by electric arc discharge technique, as monitored in three single mode optical fibers supplied by different manufacturers. A real-time measurement of LPGs’ wavelength shift was performed until a total dose of 35 kGy was reached, with average dose rate of 0.18 kGy/h, the irradiation being done at room temperature. In one case, a maximum radiation sensitivity of 1.34 nm/kGy was recorded for doses up to 0.5 kGy. Moreover, by combining experimental results with numerical simulations, it was found that changes occurred in the core refractive index of the irradiated optical fibers up to 2.5 • 10‑5. The increase of the core thermo-optic coefficient up to 1.5 • 10‑8/°C was observed as well.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. Magic memories: young children's verbal recall after a 6-year delay.

    PubMed

    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 event, including 2 who were under 3 years old when the event occurred. This may be the most convincing evidence to date that such early experiences can be verbally recalled after long delays. These data have important implications for current theories of memory development and childhood amnesia and underscore some of the problems associated with evaluating the veracity of early memories under less controlled conditions.

  6. 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

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

    NASA Astrophysics Data System (ADS)

    Pelton, Joseph N.

    2002-01-01

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

  8. Effectiveness of rotary or manual techniques for removing a 6-year-old filling material.

    PubMed

    Duarte, Marco Antônio Hungaro; Só, Marcus Vinícius Reis; Cimadon, Vanessa Buffon; Zucatto, Cristiane; Vier-Pelisser, Fabiana Vieira; Kuga, Milton Carlos

    2010-01-01

    The aim of this study was to evaluate the effectiveness of manual and rotary instrumentation techniques for removing root fillings after different storage times. Twenty-four canals from palatal roots of human maxillary molars were instrumented and filled with gutta-percha and zinc-oxide eugenol-based sealer (Endofill) , and were stored in saline for 6 years. Non-aged control specimens were treated in the same manner and stored for 1 week. All canals were retreated using hand files or ProTaper Universal NiTi rotary system. Radiographs were taken to determine the amount of remaining material in the canals. The roots were vertically split, the halves were examined with a clinical microscope and the obtained images were digitized. The images were evaluated with AutoCAD software and the percentage of residual material was calculated. Data were analyzed with two-way ANOVA and Tukey's test at 5% significance level. There was no statistically significant differences (p>0.05) between the manual and rotary techniques for filling material removal regardless the ageing effect on endodontic sealers. When only the age of the filling material was analyzed microscopically, non-aged fillings that remained on the middle third of the canals presented a higher percentage of material remaining (p<0.05) compared to the aged sealers and to the other thirds of the roots. The apical third showed a higher percentage of residual filling material in both radiographic and microscopic analysis when compared to the other root thirds. In conclusion, all canals presented residual filling material after endodontic retreatment procedures. Microscopic analysis was more effective than radiographs for detection of residual filling material.

  9. Cortisol reactions to a social evaluative paradigm in 5- and 6-year-old children.

    PubMed

    de Weerth, C; Zijlmans, M A C; Mack, S; Beijers, R

    2013-01-01

    The goal of the present study was to develop a stress paradigm to elicit cortisol secretory responses in a group of 5- and 6-year-old children as a whole. To this end, we tested a paradigm containing elements of social evaluative threat, unpredictability and uncontrollability, and with a duration of 20 min. The Children's Reactions to Evaluation Stress Test is composed of three short tasks that children have to perform in front of a judge. The tasks are rigged so as to provoke (partial) failure in the child's performance. Participants were 42 children (M = 68.0 months, SD = 4.3). Six saliva samples were taken during the testing session to obtain cortisol measurements of baseline concentrations, stress reactivity, and recovery. Our findings showed that this paradigm was effective in provoking a significant increase in salivary cortisol concentration in the group as a whole, with no effects of possible confounders (child's sex, age or school, parental educational level, time of testing, sex of experimenter, and sex of judge). The mean cortisol concentration increase for the group was 127.5% (SD = 190.9); 61% of the children could be classified as reactors (mean increase of 214%, SD = 201.5), and 39% as non-reactors (mean decrease of 7.8%, SD = 16.8). To our knowledge, this is the first study in this age group that shows a significant cortisol response for the group as a whole to a standardized laboratory paradigm. As such, this paradigm is a promising tool to be used in future research on early life interactions between physiology and psychology.

  10. 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

  11. Forensic and police identification of "X" bodies. A 6-years French experience.

    PubMed

    Cavard, S; Alvarez, J C; De Mazancourt, P; Tilotta, F; Brousseau, P; de la Grandmaison, G Lorin; Charlier, P

    2011-01-30

    The identification of X bodies is an everyday preoccupation in forensic pathology. This retrospective analysis studied all methods of identification and characteristics of unidentified bodies arrived in the Department of Forensic Medicine and Pathology (University Hospital R. Poincaré, Garches, France) during a 6-years period (2003-2009). The aim was to determine the identification methods used during all the forensic investigations, but also to study causes and manner of death in this sample of the population. A total of 9.1% of all autopsies were on X cadavers (217 cases out of 2384). On this total, only 134 of them have been included in our series after exclusion of archaeological and animal samples, but also of unidentified individuals or incomplete data available. Almost 28% of them have been identified with molecular biology (DNA), 23% with odontological examination, 7.5% with fingerprinting and 6.7% with autopsy data. Manner of death was mainly suicide (40.3%) especially by asphyxia following drowning, then accidental death (17.9%) especially consecutive to multiple trauma after traffic accident, acute carbon monoxide intoxication or carbonization in a fire. A total of 11.9% natural deaths were found (50% of them being of cardio-vascular origin) and 11.2% of homicides (with the use of firearm in a third of them). For 18.7% of X cadavers, the mode of death was undetermined. 46.4% of all unidentified bodies in our series were only identified by the police investigations, using physical recognition (direct or with photographs) or personal effects or identity documents in close relationship with the body. Our study highlights the fact that quite half of all unidentified bodies are inhumed with an identity not scientifically proved. Bodies which remained unidentified after all investigations represent 10.2% of X cadavers (if we consider a group of 176 cases composed of our study sample of 134 cases plus 24 subjects identified just before the autopsy and the 18

  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. 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

  14. Kienböck's disease in a 6-year-old boy.

    PubMed

    Docquier, Pierre-Louis; Traore, Alidou; Hugon, Sébastien

    2009-12-01

    A case of avascular necrosis of the lunate bone in a 6-year-old boy is reported. This is the youngest child reported in literature with Kienböck's disease. Clinical and radiological healing was obtained with conservative treatment. Non-operative management is recommended in children with avascular necrosis of the lunate bone.

  15. 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...

  16. Social conformity persists at least one day in 6-year-old children.

    PubMed

    Sun, Sai; Yu, Rongjun

    2016-12-21

    Humans have a tendency to forgo their own attitudes or beliefs in order to better align with the interests of a majority, a behavioral process known as conformity. Social conformity has been widely studied among adults and adolescents, whereas experimental studies on the impact of peer influence among young children have been relatively limited. The current study aims to investigate both short-term and sustained conforming behaviors among children in situations of relatively low social pressure. Forty-one children aged 5 to 6 years rated the attractiveness of 90 faces presented serially followed by witnessing a group rating in the absence of peers. Subsequently, second judgement was made after 30 minutes (Experiment 1). Results show that 6-year-old children tended to conform to their peers when group ratings differed from their own ratings, while younger children did not. In Experiment 2, children were required to make the second judgment one day after exposure to group ratings. Similarly, children aged 6 years exhibited a sustained conformity effect even after one day. Our findings suggest that 6-year-old children spontaneously change their private opinions under implicit social influence from peers.

  17. Multifocal leiomyosarcomatosis in a 6-year-old child with epidermodysplasia verruciformis and immune defect.

    PubMed

    Boybeyi, Ozlem; Akçören, Zuhal; Oğuz, Berna; Akyüz, Canan; Sanal, Ozden; Ergin, Sibel; Ersoy-Evans, Sibel; Tanyel, F Cahit

    2009-07-01

    Leiomyosarcoma and epidermodysplasia verruciformis are rarely encountered in children. The association of either leiomyosarcoma or epidermodysplasia verruciformis with immune deficiency has previously been documented. A 6-year-old girl, who has had multifocal leiomyosarcomatosis after the previous diagnoses of epidermodysplasia verruciformis and immune defect, represents an interesting association of these features.

  18. Sampling Survey on Intellectual Disability in 0-6-Year-Old Children in China

    ERIC Educational Resources Information Center

    Xie, Z.-H.; Bo, S.-Y.; Zhang, X.-T.; Liu, M.; Zhang, Z.-X.; Yang, X.-L.; Ji, S.-R.; Yan, H.; Sui, X.-L.; Na, X.; Guo, S.-H.; Wu, Z.-L.

    2008-01-01

    Objectives: To understand the current status of intellectually disabled children and the prevalence of intellectual disability (ID) in children aged 0-6 years and its risk factors, and to provide scientific evidence to formulate relevant policies for helping intellectually disabled children. Methods: Multiphase, stratified, unequal proportional…

  19. 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…

  20. 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…

  1. 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…

  2. 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…

  3. Septic arthritis of the temporomandibular joint in a 6-year-old child.

    PubMed

    Amos, M J; Patterson, A R; Worrall, S F

    2008-04-01

    Septic arthritis of the temporomandibular joint (TMJ) is rare, and is almost exclusively confined to adults; we know of only four cases previously described in children. We present a 6-year-old girl who had septic arthritis of the temporomandibular joint with no obvious cause. We stress the need for prompt diagnosis and intervention to prevent serious consequences.

  4. 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,…

  5. Social conformity persists at least one day in 6-year-old children

    PubMed Central

    Sun, Sai; Yu, Rongjun

    2016-01-01

    Humans have a tendency to forgo their own attitudes or beliefs in order to better align with the interests of a majority, a behavioral process known as conformity. Social conformity has been widely studied among adults and adolescents, whereas experimental studies on the impact of peer influence among young children have been relatively limited. The current study aims to investigate both short-term and sustained conforming behaviors among children in situations of relatively low social pressure. Forty-one children aged 5 to 6 years rated the attractiveness of 90 faces presented serially followed by witnessing a group rating in the absence of peers. Subsequently, second judgement was made after 30 minutes (Experiment 1). Results show that 6-year-old children tended to conform to their peers when group ratings differed from their own ratings, while younger children did not. In Experiment 2, children were required to make the second judgment one day after exposure to group ratings. Similarly, children aged 6 years exhibited a sustained conformity effect even after one day. Our findings suggest that 6-year-old children spontaneously change their private opinions under implicit social influence from peers. PMID:28000745

  6. Repair in the Peer Talk of 6-Year-Old Boys

    ERIC Educational Resources Information Center

    Newbold, Elisabeth J.; Howard, Sara; Wells, Bill

    2011-01-01

    This article reports a qualitative analysis of linguistic and interactional aspects of repair in naturalistic play, interaction between three 6-year-olds (C, D and F), one of whom (child D) displays some speech and language difficulties. The methodology draws on conversation analysis together with perceptual phonetic observation. The analysis…

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

    PubMed

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

    2014-05-01

    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.

  8. Normative Childhood Repetitive Routines and Obsessive Compulsive Symptomatology in 6-Year-Old Twins

    ERIC Educational Resources Information Center

    Bolton, Derek; Rijsdijk, Fruhling; Eley, Thalia C.; O'Connor, Thomas G.; Briskman, Jacqueline; Perrin, Sean

    2009-01-01

    Background: To investigate the association between normative repetitive routines of childhood and paediatric obsessive compulsive symptom syndrome (OCSS) and the extent to which it is genetically mediated. Methods: In a two-phase design a community sample of 4,662 6-year-old twin-pairs were sampled and 854 pairs were assessed in the second phase…

  9. The Effects of Folk Dance Training on 5-6 Years Children's Physical and Social Development

    ERIC Educational Resources Information Center

    Biber, Kazim

    2016-01-01

    The purpose of this study is to analyze the effects of folk dance training on 5-6 year old Pre-school children's physical and social development. The experimental design with an experimental and control group was used in accordance with the quantitative research methods in this research. The research has been conducted with the participation of 40…

  10. 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,…

  11. 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…

  12. Reference values for craniofacial structures in children 4 to 6 years old: review of the literature.

    PubMed

    Hönn, Mirjam; Göz, Gernot

    2007-05-01

    This review article addresses the question as to what methods can be used to investigate cranial structure and growth development in children 4 to 6 years old, and what the relevant reference values are for this age group. We screened the literature for epidemiological, longitudinal and cross-sectional studies investigating healthy children 4 to 6 years old without abnormalities and orthodontic therapy. Radiographic cephalometry is a practical, valid tool for analyzing craniofacial structure and growth processes. But it has several disadvantages, including the use of ionizing radiation, measuring points that are difficult to locate, no means of radiographic enlargement without distorting reference values, and the data's two-dimensionality. Anthropometry is another procedure for creating reference values for the craniofacial structure in children. Its advantages over radiographic cephalometry include three-dimensional results and no radiation exposure. Moreover, it yields precise and valid results for a wide variety of potential applications. In addition to these procedures, there are other techniques with which cranial structure and growth development in children 4 to 6 years old can be investigated. Those reported in the literature in this connection include standardized photographs, the creation of computerized and magnetic resonance images, and investigations performed on dry skulls. In short, there is great demand nowadays for investigations aimed at developing reference values for Caucasian children 4 to 6 years old. Radiographic cephalometry and anthropometry are two very common methods. Anthropometry is expected to become increasingly important because it involves no exposure to radiation.

  13. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  15. 45 CFR 287.55 - What time frames and guidelines apply regarding the obligation and liquidation periods for NEW...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

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

  16. 41 CFR 302-11.23 - When must I request to have my initial time period extended?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  17. 41 CFR 302-11.23 - When must I request to have my initial time period extended?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  18. 41 CFR 302-11.23 - When must I request to have my initial time period extended?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  19. 41 CFR 302-11.23 - When must I request to have my initial time period extended?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  1. [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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

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

    NASA Astrophysics Data System (ADS)

    Gupta, Samit Kumar; Sarma, Amarendra K.

    2014-10-01

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

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

    PubMed

    Zaks, Michael A; Goldobin, Denis S

    2010-01-01

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

  5. Diet quality across early childhood and adiposity at 6 years: the Southampton Women's Survey

    PubMed Central

    Okubo, H; Crozier, S R; Harvey, N C; Godfrey, K M; Inskip, H M; Cooper, C; Robinson, S M

    2015-01-01

    Background: Poor diet quality in early childhood is inconsistently linked to obesity risk. Understanding may be limited by the use of cross-sectional data and the use of body mass index (BMI) to define adiposity in childhood. Objective: The objective of this study is to examine the effects of continued exposure to diets of varying quality across early childhood in relation to adiposity at 6 years. Methods: One thousand and eighteen children from a prospective UK birth cohort were studied. Diet was assessed using food frequency questionnaires when the children were aged 6 and 12 months, and 3 and 6 years; diet quality was determined according to scores for a principal component analysis-defined dietary pattern at each age (characterized by frequent consumption of fruits, vegetables and fish). At each age, children were allocated a value of 0/1/2 according to third of the distribution (bottom/middle/top) their diet quality score was in; values were summed to calculate an overall diet quality index (DQI) for early childhood (range 0–8). Obesity outcomes considered at 6 years were dual-energy X-ray absorptiometry-assessed fat mass and BMI. Results: One hundred and seven (11%) children had a DQI=0, indicating a consistently low diet quality, 339 (33%) had a DQI=1–3, 378 (37%) had a DQI=4–6 and 194 (19%) had a DQI=7–8. There was a strong association between lower DQI and higher fat mass z-score at 6 years that was robust to adjustment for confounders (fat mass s.d. per 1-unit DQI increase: β=−0.05 (95% confidence interval (CI): −0.09, −0.01), P=0.01). In comparison with children who had the highest diet quality (DQI=7–8), this amounted to a difference in fat mass of 14% (95% CI: 2%, 28%) at 6 years for children with the poorest diets (DQI=0). In contrast, no independent associations were observed between DQI and BMI. Conclusions: Continued exposure to diets of low quality across early childhood is linked to adiposity at the age of 6 years. PMID:26121960

  6. 45 CFR 402.26 - Time period for obligation and expenditure of grant funds.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

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

  7. [Investigation on events of bus on fire in 6 years in the mainland of China].

    PubMed

    Wang, X G; Liu, Y; Cen, Y; Wu, P; Zhou, H L; Han, C M

    2016-12-20

    Objective: To retrospectively analyze the characteristics of events of bus on fire in 6 years in the mainland of China. Methods: Events of bus on fire happened between January 2009 and December 2014 were retrieved through Baidu search engine, Chinese Journals Full-text Database, and PubMed database in the search strategy with " bus" and " fire" or " arson" as keywords combined with the name of provinces, autonomous regions, and municipalities of the mainland of China. The occurrence time, region, cause of fire, casualties of each event were recorded, and the correlative analysis was conducted. Data were processed with Microsoft Excel software. Results: Totally 287 events of bus on fire were retrieved, among which 49 events happened in 2009, 36 events happened in 2010, 35 events happened in 2011, 37 events happened in 2012, and respectively 65 events happened in 2013 and 2014. The events of bus on fire most frequently happened in June and July, respectively 49 and 39 events. Among the distribution of occurrence regions of events of bus on fire, there were 78 events (27.18%) in east China, 52 events (18.12%) in northeast China, 41 events (14.29%) both in north China and south China. Among the causes of events of bus on fire, spontaneous combustion of bus ranked in the first (267 events, accounting for 93.03%), followed by arson (13 events, accounting for 4.53%). Among the 13 events of bus on fire caused by arson, 7 events happened between 16: 00 and 20: 00, and 3 events happened between 8: 00 and 10: 00. Totally 27 events of bus on fire (9.41%) were with casualties, among which 13 events (48.15%) were caused by spontaneous combustion of bus, 10 events (37.04%) were caused by arson, and 4 events (14.81%) were caused by traffic accidents. Arson caused the most severe casualties (at least 88 deaths and 287 injuries), followed by spontaneous combustion of bus (at least 35 deaths and 140 injuries) and traffic accidents (at least 9 deaths and 20 injuries). Conclusions

  8. 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.

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

    SciTech Connect

    Zhang, Jiajun; Lay, T. )

    1989-04-01

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

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

    PubMed

    Li, Bing; Li, Yongkun; Zhang, Xuemei

    2016-01-01

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

  11. Estimated cost of a factitious disorder with 6-year follow-up.

    PubMed

    Hoertel, Nicolas; Lavaud, Pierre; Le Strat, Yann; Gorwood, Philip

    2012-12-30

    Long-term follow up is rarely described for patients with Factitious Disorder, mainly because of the lack of access to patient's confidential information. In addition, the financial burden of multiple uses of health care system has not been examined so far. We report a 6-year follow-up for a patient with Factitious Disorder who first reported neurological then psychiatric symptoms, and investigate the cost of his detected hospitalizations.

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

    SciTech Connect

    Kalvoda, T.; Stovicek, P.

    2011-10-15

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

  13. Mediation of a preventive intervention's 6-year effects on health risk behaviors.

    PubMed

    Soper, Ana C; Wolchik, Sharlene A; Tein, Jenn-Yun; Sandler, Irwin N

    2010-06-01

    Using data from a 6-year longitudinal follow-up sample of 240 youth who participated in a randomized experimental trial of a preventive intervention for divorced families with children ages 9 to 12, the current study tested mechanisms by which the intervention reduced substance use and risky sexual behavior in mid to late adolescence (15-19 years old). Mechanisms tested included parental monitoring, adaptive coping, and negative errors. Parental monitoring at 6-year follow-up mediated program effects to reduce alcohol and marijuana use, polydrug use, and other drug use for those with high pretest risk for maladjustment. In the condition that included a program for mothers only, increases in youth adaptive coping at 6-year follow-up mediated program effects on risky sexual behavior for those with high pretest risk for maladjustment. Contrary to expectation, program participation increased negative errors and decreased adaptive coping among low-risk youth in some of the analyses. Ways in which this study furthers our understanding of pathways through which evidence-based preventive interventions affect health risk behaviors are discussed.

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

    NASA Astrophysics Data System (ADS)

    Wang, Mingxin; Zhang, Yang

    2016-10-01

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

  15. Ozone exposure during the early postnatal period alters the timing and pattern of alveolar growth and development in nonhuman primates.

    PubMed

    Avdalovic, Mark V; Tyler, Nancy K; Putney, Lei; Nishio, Susie J; Quesenberry, Sherri; Singh, Parmjit J; Miller, Lisa A; Schelegle, Edward S; Plopper, Charles G; Vu, Thiennu; Hyde, Dallas M

    2012-10-01

    Exposure to oxidant air pollutants in early childhood, with ozone as the key oxidant, has been linked to significant decrements in pulmonary function in young adults and exacerbation of airway remodeling in asthma. Development of lung parenchyma in rhesus monkeys is rapid during the first 2 years of life (comparable to the first 6 years in humans). Our hypothesis is that ozone inhalation during infancy alters alveolar morphogenesis. We exposed infant rhesus monkeys biweekly to 5, 8 hr/day, cycles of 0.5 ppm ozone with or without house dust mite allergen from 1 to 3 or 1 to 6 months of age. Monkeys were necropsied at 3 and 6 months of age. A morphometric approach was used to quantify changes in alveolar volume and number, the distribution of alveolar size, and capillary surface density per alveolar septa. Quantitative real time PCR was used to measure the relative difference in gene expression over time. Monkeys exposed to ozone alone or ozone combined with allergen had statistically larger alveoli that were less in number at 3 months of age. Alveolar capillary surface density was also decreased in the ozone exposed groups at 3 months of age. At 6 months of age, the alveolar number was similar between treatment groups and was associated with a significant rise in alveolar number from 3 to 6 months of age in the ozone exposed groups. This increase in alveolar number was not associated with any significant increase in microvascular growth as measured by morphometry or changes in angiogenic gene expression. Inhalation of ozone during infancy alters the appearance and timing of alveolar growth and maturation. Understanding the mechanism involved with this altered alveolar growth may provide insight into the parenchymal injury and repair process that is involved with chronic lung diseases such as severe asthma and COPD.

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

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

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

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

    ERIC Educational Resources Information Center

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

    2012-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Kim, Nakwoo

    2015-03-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

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

    PubMed

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

    2009-08-28

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

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

    SciTech Connect

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

    2009-08-28

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

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

    PubMed

    Zhang, Ancai; Qiu, Jianlong; She, Jinhua

    2014-02-01

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

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

    PubMed

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

    2016-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2010-07-01

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

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

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

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

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

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

    PubMed

    Wierzcholski, Krzysztof

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Kim, M.; Harman, C. J.

    2013-12-01

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

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2009-07-01

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

  12. The Effectiveness of Activity-Based Intervention Program on the Transition Skills of Children with Developmental Disabilities Aged between 3 and 6 Years

    ERIC Educational Resources Information Center

    Bakkaloglu, Hatice

    2008-01-01

    Seven children aging between 3 and 6 years with developmental disabilities were participated in this study, which examined the effects of the Activity-Based Intervention Program (ABIP) on the transition skills. The study used time series design and the implementation process was composed of "before instruction phase", "instruction…

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

    PubMed

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

    2016-10-05

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

  14. A 6-year exercise program improves skeletal traits without affecting fracture risk: a prospective controlled study in 2621 children.

    PubMed

    Detter, Fredrik; Rosengren, Björn E; Dencker, Magnus; Lorentzon, Mattias; Nilsson, Jan-Åke; Karlsson, Magnus K

    2014-06-01

    Most pediatric exercise intervention studies that evaluate the effect on skeletal traits include volunteers and follow bone mass for less than 3 years. We present a population-based 6-year controlled exercise intervention study in children with bone structure and incident fractures as endpoints. Fractures were registered in 417 girls and 500 boys in the intervention group (3969 person-years) and 835 girls and 869 boys in the control group (8245 person-years), all aged 6 to 9 years at study start, during the 6-year study period. Children in the intervention group had 40 minutes daily school physical education (PE) and the control group 60 minutes per week. In a subcohort with 78 girls and 111 boys in the intervention group and 52 girls and 54 boys in the control group, bone mineral density (BMD; g/cm(2) ) and bone area (mm(2) ) were measured repeatedly by dual-energy X-ray absorptiometry (DXA). Peripheral quantitative computed tomography (pQCT) measured bone mass and bone structure at follow-up. There were 21.7 low and moderate energy-related fractures per 1000 person-years in the intervention group and 19.3 fractures in the control group, leading to a rate ratio (RR) of 1.12 (0.85, 1.46). Girls in the intervention group, compared with girls in the control group, had 0.009 g/cm(2) (0.003, 0.015) larger gain annually in spine BMD, 0.07 g (0.014, 0.123) larger gain in femoral neck bone mineral content (BMC), and 4.1 mm(2) (0.5, 7.8) larger gain in femoral neck area, and at follow-up 24.1 g (7.6, 40.6) higher tibial cortical BMC (g) and 23.9 mm(2) (5.27, 42.6) larger tibial cross-sectional area. Boys with daily PE had 0.006 g/cm(2) (0.002, 0.010) larger gain annually in spine BMD than control boys but at follow-up no higher pQCT values than boys in the control group. Daily PE for 6 years in at study start 6- to 9-year-olds improves bone mass and bone size in girls and bone mass in boys, without affecting the fracture risk.

  15. 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

  16. Gradual improvement in fine-grained sensitivity to triadic gaze after 6 years of age.

    PubMed

    Vida, Mark D; Maurer, Daphne

    2012-02-01

    The current research compared the ability of adults and children to determine where another person is looking in shared visual space (triadic gaze). In Experiment 1, children (6-, 8-, 10-, and 14-year-olds) and adults viewed photographs of a model fixating a series of positions separated by 1.6° along the horizontal plane. The task was to indicate whether the model was looking to the left or right of one of three target positions (midline, 6.4° left, or 6.4° right). By 6 years of age, thresholds were quite small (M=1.94°) but were roughly twice as large as those of adults (M=1.05°). Thresholds decreased to adult-like levels around 10 years of age. All age groups showed the same pattern of higher sensitivity for central targets than peripheral targets and of misjudging gaze toward peripheral targets as farther from midline than it really was. In subsequent experiments, we evaluated possible reasons for the higher thresholds in 6- and 8-year-olds. In Experiment 2, the thresholds of 6-year-olds did not improve when the range of deviations from the target position that the model fixated covered a much wider range. In Experiment 3, 8-year-olds were less sensitive than adults to small shifts in eye position even though the task required only matching faces with the same eye position and not determining where the person was looking. These findings suggest that by 6 years of age, children are quite sensitive to triadic gaze, which may support inferences about others' interests and intentions. Subsequent improvements in sensitivity involve, at least in part, an increase in sensitivity to eye position.

  17. 40 CFR 93.162 - Emissions beyond the time period covered by the SIP.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  18. Prosthetic Management of a Child with Hypohidrotic Ectodermal Dysplasia: 6-Year Follow-Up

    PubMed Central

    Conceição Pinto, Moara e Silva; Melo do Val, Cinthya; Costa Oliveira, Leonam; Costa de Aquino, Cristhyane

    2016-01-01

    Ectodermal dysplasia (ED) is a genetically heterogeneous condition resulting from clinical anomalies of structures derived from the ectoderm, such as the hair, nails, sweat glands, and teeth. This clinical report presents the case of a child diagnosed with hypohidrotic ED at 2 years of age; clinical and imaging evaluation was performed with 6-year follow-up, and we present details of the prosthetic dental care, with a 12-month follow-up. The patient's masticatory capacity had improved, leading to the child gaining 4 kg. In conclusion, prosthetic management was noninvasive and appeared to lead to developmental benefits for the patient. PMID:27822392

  19. A Case of Juvenile Huntington Disease in a 6-Year-Old Boy

    PubMed Central

    Sunwoo, Jun-Sang; Lee, Soon-Tae; Kim, Manho

    2010-01-01

    Huntington disease is a neurodegenerative disorder distinguished by the triad of dominant inheritance, choreoathetosis and dementia, usually with onset in the fourth and fifth decades. It is caused by an unstable cytosine-adenine-guanine (CAG) trinucleotide repeat expansion in the gene IT15 in locus 4p16.3. Juvenile HD that constitutes about 3% to 10% of all patients is clinically different from adult-onset form and characterized by a larger number of CAG repeats typically exceeding 60. We report a case of a 6-year-old boy with myoclonic seizure and 140 CAG repeats confirmed by molecular genetic analysis. PMID:24868381

  20. [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.

  1. Biopsychosocial consequences of sweetened drink consumption in children 0-6 years of age.

    PubMed

    Saalfield, Sarah; Jackson-Allen, Patricia

    2006-01-01

    North American children consume an extraordinary amount of sweetened drinks--sodas, juice drinks, and "ades." Health care providers, educators, and parents have long been concerned about the effects sweetened drink consumption (SDC) has on the bodies and minds of children. This review of the literature will examine the current evidence regarding the factors contributing to excess SDC, and the health consequences of SDC consumption in children, especially infants and children under 6 years of age, with the goal of informing clinical pediatric nursing, future research, and policy development aimed at reversing the long-standing trend of rising SDC.

  2. Vaccine-Induced Anti-HBs Level in 5-6 Year-Old Malnourished Children

    PubMed Central

    Karimi, Mehran; Raee, Ali; Baghianimoghadam, Behnam; Fallahzadeh, Mohammad Hossein

    2013-01-01

    Background Malnutrition is the most common cause of immune deficiency. It results in reduced secretion of T-cells and B-cell-stimulating factors leading to declining of special immunoglobulins. On the other hand, hepatitis B, as a major world health problem, can be prevented effectively by vaccination. Three doses of hepatitis B virus (HBV) vaccine induce protective levels of anti-hepatitis B surface (anti-HBs) in 95% of healthy children. This level decreases gradually over time. Objectives The goal of this study was to assess anti-HBs in malnourished children, who confronted to some degrees of immune deficiency. Patients and Methods This is a cross-sectional study conducted during May to August 2010 in therapeutic clinics of Yazd, Iran. Samples were selected simply and consecutively among 5-6 year-old children with a history of three doses of HBV vaccine in infancy. On the basis of World Health Organization’s definition on malnutrition, which considers anthropometric measurements, malnourished children entered the study. Totally 83 cases (37 boys and 46 girls) were gathered and classified into three groups of mild, moderate, and severe malnutrition. One milliliter of venous blood was taken and anti-HBs were tested by enzyme linked immunosorbant assay (ELISA). Results Overall, seroprotection rate and geometric mean titer (GMT) of anti-HBs were 60.2% and 15.47 ± 10.92 mIU/mL, respectively. Seroprotection rate was 71.4%, 55.2%, and 72.7% in mild, moderate, and severe malnourished children, respectively. GMT was 30.78 mIU/mL, 12.15 mIU/mL, and 22.95 mIU/mL in these groups, respectively. None of these two indices were significant in these groups (P = 0.471, P = 0.364). Seroprotection rate and GMT were 54.1% and 13.26 ± 11.59 mIU/mL in boys, and 65.2% and 17.5 ± 10.59 mIU/mL in girls, respectively, showing no significant relationship with gender (P = 0.302, P = 0.602). Lowest seroprotection rate was in stunted cases (47.1%) and highest in wasted children (77

  3. 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.

  4. 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.

  5. 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.

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

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  7. 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

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

    NASA Astrophysics Data System (ADS)

    Marks, Dennis

    2007-04-01

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

  9. 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.

  10. Hospital care for primary hyperparathyroidism in Italy: a 6-year register-based study

    PubMed Central

    Cipriani, Cristiana; Carnevale, Vincenzo; Biamonte, Federica; Piemonte, Sara; Pepe, Jessica; Nieddu, Luciano; Bilezikian, John P; Minisola, Salvatore

    2015-01-01

    Objective Primary hyperparathyroidism (PHPT) is one of the most frequently diagnosed endocrine disorders, but few studies have focused on hospital management of the disease in Europe. We investigated the frequency of hospital admission for diagnosis and surgical treatment of PHPT in Italy. Design A retrospective study was conducted for investigating the hospital care for PHPT in Italy. Methods We retrieved data from the ‘Record of Hospital Discharge’ of the Italian Health Ministry, from 2006 to 2011, and analyzed the codes corresponding to PHPT-related diagnoses and surgical procedures. Results Overall, 46 275 hospitalization episodes for PHPT were identified during the entire period (69% in women and 31% in men; mean age 63.3±39.8 years). Patients’ mean age significantly increased during the years (P<0.001). The mean length of stay was 8.2±10.5 days (28% of the episodes requiring <3 days of stay). Admissions for surgical procedures were 12 457 accounting for 26.9% of the total hospitalizations. There was a trend to a significant increase in the percentage of surgery (P<0.05). The mean hospitalization rate for PHPT was 12.9/100 000 inhabitants per year and the trend showed a significant decrease during the period of 2006–2011 (P<0.0001). The mean hospitalization rate for PHPT surgery was 3.65/100 000 per year, which significantly increased over time (P<0.001). Conclusions PHPT considerably influences the Italian Hospital healthcare system. We observed a tendency to a decrease in the frequency of hospitalization during the period of 2006–2011, most probably because of economic issues, a concomitant increased age of patients, and, interestingly, also a progressive increase in the percentage of surgical treatment among patients admitted for PHPT. PMID:25015979

  11. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  13. Prevalence and duration of PTSD in survivors 6 years after a natural disaster.

    PubMed

    Arnberg, Filip K; Bergh Johannesson, Kerstin; Michel, Per-Olof

    2013-04-01

    The present study aimed to examine the prevalence of posttraumatic stress disorder (PTSD) in survivors with low levels of risk factors for PTSD. The sample included 142 adults (58% women, 54% university education, 93% employed/students/retired) on vacation in Southeast Asia during the 2004 Indian Ocean disaster. Semi-structured clinical interviews (SCID-I) were performed after 6 years including PTSD, depression, specific phobia, and alcohol abuse. The 6-year prevalence of PTSD was 11.3% and the current prevalence was 4.2%, with onset mainly within 1 month and remission within 3 years post-disaster. Suicidal ideation and comorbidity were common in PTSD cases. Lifetime prevalence of depression was 19%, specific phobia 7%, and alcohol abuse 4%. The findings suggest elevated levels of PTSD but not other disorders as compared with general population samples, but still lower levels than other disaster samples. Despite benign circumstances, however, the course and burden of PTSD were comparable to similar studies.

  14. 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

  15. 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

  16. DISCOVERY OF A 1.6 YEAR MAGNETIC ACTIVITY CYCLE IN THE EXOPLANET HOST STAR {iota} HOROLOGII

    SciTech Connect

    Metcalfe, T. S.; Judge, P. G.; Knoelker, M.; Mathur, S.; Rempel, M.; Basu, S.; Henry, T. J.; Soderblom, D. R.

    2010-11-10

    The Mount Wilson Ca HK survey revealed magnetic activity variations in a large sample of solar-type stars with timescales ranging from 2.5 to 25 years. This broad range of cycle periods is thought to reflect differences in the rotational properties and the depths of the surface convection zones for stars with various masses and ages. In 2007, we initiated a long-term monitoring campaign of Ca II H and K emission for a sample of 57 southern solar-type stars to measure their magnetic activity cycles and their rotational properties when possible. We report the discovery of a 1.6 year magnetic activity cycle in the exoplanet host star {iota} Horologii and obtain an estimate of the rotation period that is consistent with Hyades membership. This is the shortest activity cycle so far measured for a solar-type star and may be related to the short-timescale magnetic variations recently identified in the Sun and HD 49933 from helioseismic and asteroseismic measurements. Future asteroseismic observations of {iota} Hor can be compared to those obtained near the magnetic minimum in 2006 to search for cycle-induced shifts in the oscillation frequencies. If such short activity cycles are common in F stars, then NASA's Kepler mission should observe their effects in many of its long-term asteroseismic targets.

  17. 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

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

    NASA Astrophysics Data System (ADS)

    Reichenbach, Tobias; Hudspeth, A. J.

    2012-11-01

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

  19. 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.

  20. 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.

  1. 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.

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

    NASA Astrophysics Data System (ADS)

    Mundil, R.

    2009-05-01

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

  3. 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

  4. Diode Laser Versus Scalpel in the Treatment of Hereditary Gingival Fibromatosis in a 6-Year Old Boy

    PubMed Central

    Aboujaoude, Samia; Cassia, Antoine; Moukarzel, Carla

    2016-01-01

    Hereditary gingival fibromatosis (HGF) is a rare disease characterized by a benign enlargement of the gingiva involving both the mandible and the maxilla. This case is about a 6-year-old child with non syndromic HGF showing a severe gingival enlargement covering almost all surfaces of the teeth, in both arches, hence causing major aesthetic, phonetic and masticatory problems. The aim of the present article is to compare the outcomes of two therapeutical approaches: i) classical surgical removal with scalpel; and ii) diode laser resection. Compared to the surgical approach, the clinical results show that the main advantages of the diode laser technique are a better visibility during the intervention, minimal postoperative discomfort combined to a better gingival recontouring. However, the time consumption and the high cost of the laser equipment remain the main disadvantages of the systematic use of this technique. PMID:27994842

  5. 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.

  6. Primary Cerebellar Neuroendocrine Tumors: Chimeras or Real Entities? A Case Report with a 6-Year Follow-Up.

    PubMed

    Vernieri, Claudio; Femia, Daniela; Pusceddu, Sara; Capella, Carlo; Rosai, Juan; Calareso, Giuseppina; Concas, Laura; Prinzi, Natalie; Lo Russo, Giuseppe; de Braud, Filippo; Buzzoni, Roberto

    2016-01-01

    We report the case of a 38-year-old patient who was diagnosed with a cerebellar well-differentiated neuroendocrine tumor (WDNET) in 2009. At first glance, we believed that it was a metastasis from an unrecognized WDNET arising outside the cerebellum. However, despite a prolonged follow-up of 6 years, an extracranial WDNET has never been found. During this time, the tumor recurred locally twice, and the patient was treated with surgery and radiotherapy. At the moment, he enjoys good general conditions and his tumor is under control. Due to the histopathological characteristics and clinical behavior of the tumor, we believe that this is the first report to date of a primary cerebellar WDNET.

  7. Primary Cerebellar Neuroendocrine Tumors: Chimeras or Real Entities? A Case Report with a 6-Year Follow-Up

    PubMed Central

    Vernieri, Claudio; Femia, Daniela; Pusceddu, Sara; Capella, Carlo; Rosai, Juan; Calareso, Giuseppina; Concas, Laura; Prinzi, Natalie; Russo, Giuseppe Lo; de Braud, Filippo; Buzzoni, Roberto

    2016-01-01

    We report the case of a 38-year-old patient who was diagnosed with a cerebellar well-differentiated neuroendocrine tumor (WDNET) in 2009. At first glance, we believed that it was a metastasis from an unrecognized WDNET arising outside the cerebellum. However, despite a prolonged follow-up of 6 years, an extracranial WDNET has never been found. During this time, the tumor recurred locally twice, and the patient was treated with surgery and radiotherapy. At the moment, he enjoys good general conditions and his tumor is under control. Due to the histopathological characteristics and clinical behavior of the tumor, we believe that this is the first report to date of a primary cerebellar WDNET. PMID:27721764

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

    DTIC Science & Technology

    2010-03-09

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

  9. Evaluating long-term effects of heroin-assisted treatment: the results of a 6-year follow-up.

    PubMed

    Güttinger, Franziska; Gschwend, Patrick; Schulte, Bernd; Rehm, Jürgen; Uchtenhagen, Ambros

    2003-04-01

    Since January 1994, heroin-assisted treatment for opiate addicts has been available in Switzerland. This is the first report of the long-term effects of this form of treatment. The report examines subjects who entered a study involving medical prescription of opiates (Projekt zur ärztlichen Verschreibung von Betäubungsmitteln; PROVE) in Switzerland between January 1994 and March 1995 (n = 366). Opiates were dispensed in eight treatment centres. A follow-up was conducted 6 years after treatment entry. Two groups were assessed: clients who have continuously been on heroin-assisted treatment since entry into the PROVE study or who re-entered this treatment, and ex-clients who had discontinued heroin-assisted treatment at the time of follow-up. Two kinds of comparisons were conducted. Firstly, conditions at treatment entry were compared to 6-year follow-up outcomes, and secondly, outcomes were compared between clients still on heroin-assisted treatment and those who had been discharged. It was found that 46% of the clients still alive were on heroin-assisted treatment at the time of follow-up. A comparison of the present living conditions showed very little difference between those in treatment and those who had terminated treatment. Compared to the situation at entry, the results of the follow-up showed a significant decrease in the use of illegal substances, illegal income and most other variables concerning social conditions, but they also showed an increase in unemployment and reliance on social benefits. Heroin-assisted treatment is thus efficacious in the long-term course of treatment and is still effective after termination of treatment with respect to living conditions and use of illicit substances.

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

    NASA Astrophysics Data System (ADS)

    Zukovic, Miodrag; Kovacic, Ivana

    2017-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Yan, Weixian

    2017-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2017-04-01

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

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

    PubMed

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

    2012-09-01

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

  14. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

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

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

    SciTech Connect

    Mead, K.E.

    1981-11-01

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

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

    PubMed

    Brand, Willi A

    2009-06-01

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

  18. 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

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

    PubMed Central

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

    2016-01-01

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

  20. 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.

  1. 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

  2. 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

  3. The Mount Sinai cesarean section reduction program: an update after 6 years.

    PubMed

    Myers, S A; Gleicher, N

    1993-11-01

    A six year follow-up evaluation of our original cesarean section reduction program is presented. While establishing obstetric practice guidelines was accomplished, two prerequisites remain critical: lowering cesarean utilization was to be accomplished without harm to mother or fetus, and a target rate was prospectively determined. The results after 6 years indicate that total cesarean rates of 10-12% can consistently be achieved without adverse outcome. Additionally, operative vaginal procedures were employed less that 3% of cases. Separate analysis of 580 breech deliveries failed to show an effect of route of delivery on mortality. This effort indicates that long-term reductions and cesarean utilization are possible with a comprehensive departmental program designed to accomplish achieving a target rate of 11%.

  4. Phonological development in 4-6-year-old moderately hearing impaired children.

    PubMed

    Huttunen, K H

    2001-01-01

    The acquisition of clear phonological rules is of utmost importance for a child when he/she is learning to decode and convey meanings using spoken language. Fifteen Finnish-speaking children, five normally hearing (NH) 3-year-olds and 10 moderately hearing impaired (HId) 4-6-year-olds were studied here. Speech samples consisting of 62 words were collected from each child during a picture naming task. Frequent phonetic (articulation) errors together with normal (but delayed) and deviant phonological processes of HId children were found in this study. The frequency and quality of the processes seemed to be related more to the grade of HI than, for example, the age of the child. Implications for speech therapy are briefly discussed.

  5. Rules for pluralization in African American English: Evidence from 4-, 5-, and 6-year-olds

    NASA Astrophysics Data System (ADS)

    Trent-Brown, Sonja A.

    2005-09-01

    This study investigated the African American English (AAE) forms produced by 4-, 5-, and 6-year-old children when pluralizing words ending in final consonant clusters. Participants were 105 child and 45 adult speakers of AAE. Speakers provided verbal responses to pictures of cartoon-like creatures with nonsense word names. Responses were recorded and presented to experienced listeners for language set and singular versus plural judgments. An acoustical analysis was conducted for comparison to the perceptual findings. Results suggest that although [s] inflection is nonobligatory in AAE, there are many instances in which it does occur. Variation in plural forms across final consonant clusters is discussed as well as other markers for pluralization in the absence of the [s] morpheme.

  6. Secretory breast carcinoma in a 6-year-old girl: mastectomy with sentinel lymph node dissection.

    PubMed

    Soyer, Tutku; Yaman Bajin, İnci; Orhan, Diclehan; Yalçin, Bilgehan; Özgen Kiratli, Pinar; Oğuz, Berna; Karnak, İbrahim

    2015-07-01

    Secretory breast carcinoma (SBC) is a rare type of breast neoplasia that was originally described in children. SBC is an indolent breast tumor with good clinical outcome and rare systemic involvement. Since, majority of studies concerning pediatric SBC have been case reports, it has been difficult to clearly elucidate the characteristics and optimal treatment strategies for SBC in children. Although treatment recommendations vary, surgical excision is the primary mode of treatment. Also, necessity of axillary and/or sentinel lymph node dissection is another matter of discussion in children. We report a 6-year-old girl who was diagnosed as SBC was reported to discuss the use of mastectomy with sentinel lymph node dissection in the treatment of this rare tumor in children.

  7. Laparoscopic radical prostatectomy: Oncological outcome analysis from a single-center Indian experience of 6 years

    PubMed Central

    Mishra, Shashikant; Agrawal, Vikas; Khatri, Naushad; Sharma, Rajan; Kurien, Abraham; Ganpule, Arvind; Muthu, V.; Sabnis, Ravindra B.; Desai, Mahesh R.

    2012-01-01

    Background: There is a lack of published data on laparoscopic radical prostatectomy (LRP) in India. Although the published short-term oncologic outcomes after LRP are encouraging, intermediate and long-term data are lacking. Objective: We analyzed the oncological outcome after LRP based on 6 years of experience and compared it with the other single-center published literature. Materials and Methods: Of the 90 patients who underwent LRP for a clinical T2 localized disease, 73 patients with at least a follow up of one year were analyzed. Patients were classified as low-, intermediate-, and high-risk D′Amico groups in 22 (30%), 26 (36%), and 25 (34%) of the patient population, respectively. Progression of disease was defined as a PSA of 0.4ng/ml with a confirmatory rise. We used Kaplan-Meier product limit estimates to calculate actuarial 5-year probabilities of biochemical progression-free survival. Univariate analysis of risk factors for biochemical recurrence (BCR) was done. Results: The mean age of the patients was 63.3 ± 6.6 years. The average follow-up for patients was 22 (12-72) months. There was no prostatic cancer-specific mortality. Fourteen patients had BCR. The 5-year progression-free probability for men with low-, intermediate-, and high-risk prostate cancers was 91%, 82%, and 58%, respectively. High-risk group, Gleason sum more than 8, extracapsular extension, and positive surgical margin were significantly associated with biochemical progression. Conclusions: LRP provided a similar level of oncological success as reported by the other contemporary single-center published literature PMID:22557714

  8. Psychometric Properties of a Caregiver Illness Perception Measure for Caries in Children Under 6 Years Old

    PubMed Central

    Nelson, Suchitra; Slusar, Mary Beth; Albert, Jeffrey M.; Liu, Yiying; Riedy, Christine A.

    2016-01-01

    Objective Based on the Common-Sense Model of Self-Regulation (CSM), the Revised Illness Perception Questionnaire (IPQ-R) was developed to measure patients’ perceptions of their chronic medical illness. Such a measure does not exist for dental conditions. This study describes psychometric properties of the IPQ-R for Dental (IPQ-RD) for parent/caregivers of children under 6 years of age. Methods Parent/caregivers (n=160) of children aged < 6 years attending a pediatric dental clinic completed the IPQ-RD and a questionnaire assessing their socio-demographics, dental anxiety, oral health self-efficacy, and child’s preventive dental visits. Dental charts were abstracted for child’s decayed, missing, filled teeth (dmft) information. The 33-item IPQ-RD was tested for internal (construct, discriminant) and external validity (concurrent, convergent, discriminant) and reliability (internal consistency). Results Confirmatory factor analysis demonstrated that the eight-factor model in accordance with the CSM framework (identity, consequences–child, consequences–caregiver, control–child, control–caregiver, timeline, illness coherence, emotional representations) had good construct validity based on significant factor loadings and acceptable to excellent model fit (RMSEA = 0.078, CFI = 0.951). Concurrent validity was demonstrated by significant negative correlations and higher mean factor scores for five constructs for children without dental visits indicating inaccurate caregiver perception of cavities. Discriminant validity was suggested by non-relationship with external measures (dental anxiety, self-efficacy). Internal consistency of six IPQ-RD constructs was excellent (Cronbach’s alpha > 0.74). Conclusion The IPQ-RD is a valid and reliable measure to assess parent/caregivers’ representation of young children’s cavities with potential to be a valuable risk assessment tool for oral health behavioral research. PMID:26800638

  9. Waist circumference percentiles among Turkish children under the age of 6 years.

    PubMed

    Hatipoglu, Nihal; Mazicioglu, M Mumtaz; Poyrazoglu, Serpil; Borlu, Arda; Horoz, Duygu; Kurtoglu, Selim

    2013-01-01

    Waist circumference, a proxy measure of abdominal obesity, is associated with cardio-metabolic risk factors in childhood and adolescence. Although there are numerous studies about waist circumference percentiles in children, only a few studies cover preschool children. The aim of this study was to develop age- and gender-specific waist circumference smoothed reference curves in Turkish preschool children to determine abdominal obesity prevalence and to compare them with reference curves obtained from different countries. The design of the study was cross-sectional. A total of 2,947 children (1,471 boys and 1,476 girls) aged 0-6 years were included in the study. The subjects were divided according to their gender. Waist circumference was measured by using a standardized procedure. The age- and gender-specific waist circumference reference curves were constructed and smoothed with LMS method. The reference values of waist circumference, including 3rd, 10th 25th, 50th, 75th, 90th, and 97th percentiles, and standard deviations were given for preschool children. Waist circumference values increased with age, and there were differences between genders. The prevalence of abdominal obesity was calculated as 10.1 % for boys and 10.7 % for girls. Having compared our data with two other countries' data, we found that our waist circumference data were significantly lower. This is the first cross-sectional study for age- and gender-specific references of 0- to 6-year-old Turkish children. The gender- and age-specific waist circumference percentiles can be used to determine the risk of central obesity.

  10. FE NO concentrations in World Trade Center responders and controls, 6 years post-9/11.

    PubMed

    Mauer, Matthew P; Hoen, Rebecca; Jourd'heuil, David

    2011-08-01

    The aim of this study was to evaluate whether underlying respiratory disease may be revealed by offline fractional exhaled nitric oxide (FE(NO)) testing among a cohort of New York State (NYS) World Trade Center (WTC) responders in comparison with a control group of similar but unexposed NYS employees, 6 years post-9/11. Participants (92 exposed, 141 unexposed) provided two breath samples that were collected in Mylar bags and sent to a central laboratory for FE(NO) testing. Participants also completed a brief questionnaire. Ambient air pollution was characterized using particulate matter (PM(2.5)) and ozone concentration data from the NYS Department of Environmental Conservation air-monitoring sites closest to each testing site for each day of sample collection. WTC exposure did not appear to be associated with elevated FE(NO) concentrations. FE(NO) concentrations were higher on days with elevated levels of PM(2.5) (≥ 35 μg/m³) and ozone (≥ 0.08 ppm). FE(NO) concentrations were higher in men and lower in smokers. Our results do not suggest an association between WTC exposure and elevated FE(NO) concentrations, 6 years post-9/11, in this moderately exposed cohort of responders. Results do suggest that FE(NO) concentrations were elevated in relation to higher levels of ambient air pollutants. Our results also offer useful reference values for future research involving FE(NO) testing. This study demonstrates that offline FE(NO) testing is a useful method for epidemiological studies requiring collection of samples in the field, potentially over a broad geographic area.

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

    PubMed

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

    2010-02-01

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

  12. 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.

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

    PubMed Central

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

    2016-01-01

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

  14. Eustachian Tube Function in 6-Year-Old Children With and Without a History of Middle-Ear Disease

    PubMed Central

    Mandel, Ellen M.; Casselbrant, Margaretha L.; Richert, Beverly C.; Teixeira, Miriam S.; Swarts, J. Douglas; Doyle, William J.

    2015-01-01

    Objective Test the hypothesis that Eustachian tube opening efficiency measured as the fractional gradient equilibrated (FGE) is lower in 6-year-old children with no middle-ear disease but a well-documented history of recurrent acute otitis media when compared to children with a negative disease history (Control). Study Design Cross-sectional study Setting Tertiary-care pediatric hospital Subjects and Methods Bilateral Eustachian tube function was evaluated in 44 healthy 6-year-old children (19 male, 29 white). None had middle-ear disease at the time of testing, but 23 had a history of recurrent acute otitis media. Twenty-one had no significant past otitis media. Eustachian tube function was measured using a pressure-chamber protocol that established negative middle-ear gauge pressures (referenced to the chamber pressure) and recorded that pressure before and after a swallow. FGE was calculated as the change in middle-ear gauge pressure with swallowing divided by the pre-swallow pressure. Between-group comparisons of the pre-swallow pressures and FGEs were made using a 2-tailed Student’s t test. Results FGE was independent of the pre-swallow middle-ear gauge pressure. For the 39 and 44 evaluable ears in the control and recurrent acute otitis media groups, the mean pre-swallow pressures were −194 (95%CI=−211 to −177) versus −203 (95%CI=−216 to −190) daPa (P>0.40) and FGEs were 0.32 (95%CI=0.21 to 0.43) vs 0.16 (95%CI=0.08 to 0.24) (P=0.016), respectively. Conclusion In children with past recurrent acute otitis media, residual Eustachian tube opening inefficiency is maintained after the child has “outgrown” their middle-ear disease. PMID:26626132

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

    PubMed

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

    2013-01-01

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

  16. Structure of the solar oscillation with period near 160 minutes

    NASA Technical Reports Server (NTRS)

    Scherrer, P. H.; Wilcox, J. M.

    1982-01-01

    The solar oscillation with period near 160 minutes is found to be unique in a spectrum computed over the range of periods from about 71 to 278 minutes. A best estimate of the period is 160.0095 + or - 0.001 minutes, which is different from 160 minutes (one ninth of a day) by a highly significant amount. The width of the peak is approximately equal to the limiting resolution that can be obtained from an observation lasting 6 years, which suggests that the damping time of the oscillations is considerably longer than 6 years. A suggestion that this peak might be the result of a beating phenomenon between the five minute data averages and a solar oscillation with period near five minutes is shown to be incorrect by recomputing a portion of the spectrum using 15 second data averages.

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. [Health education in St. Gall schools: experiences from a 6-year project].

    PubMed

    van der Linde, F; Zuberbühler, P

    1985-01-01

    In 1982 a general concept for comprehensive health education in schools worked out by an interdisciplinary project team was introduced by the Educational Council. Health education is postulated primarily as an educational principle, but in addition to this general principle 13 distinctive content areas are put forward. In a second phase special project teams for each type of school had to transform the general concept into their own specific needs for the age groups concerned. The most important experiences from this phase can be summarized as follows: Concepts for health education in schools have to be worked out by interdisciplinary teams coordinated by an expert belonging to the educational (not the medical) system. Planning and introduction of health education has to be accompanied by changes in attitudes on all levels; the need for time must therefore not be underestimated. The project team has to discuss its results repeatedly with local educational authorities and teachers in order to ensure practicability and acceptance of its proposals. The cross-curricular nature of health education has to be stressed and to be demonstrated by working out and applying practicable models. Teachers have to be carefully prepared for their task not only by providing them with adequate material but above all by including health education as a priority in the training period as well as in postgraduate courses.

  2. A 6-year-old child with Fryns syndrome: further delineation of the natural history of the condition in survivors.

    PubMed

    Dentici, Maria Lisa; Brancati, Francesco; Mingarelli, Rita; Dallapiccola, Bruno

    2009-01-01

    Fryns syndrome (FS) is a rare early lethal autosomal recessive disorder. The diagnosis is clinical since the underlying molecular defect is currently unknown. We report on a 6-year-old male child displaying an association of congenital diaphragmatic hernia (CDH), lung hypoplasia, corneal clouding and coarse face in the absence of distal digital/nail hypoplasia. Based on the recently published diagnostic guidelines, our patient fits the narrow definition of FS. Only a minority of FS patients surviving the neonatal period have been reported, thus limiting the recognition of the infantile phenotype. We compared the features observed in our proband with those of 10 published survivors. Neurological impairment ranging from mild to severe was present in all patients, while seizures manifested in one third of them, often in association with central nervous system malformations. Other characteristic features included central-paracentral corneal clouding, coarsening of the facial traits, gastroesophageal reflux, Hirschsprung disease, intestinal malrotation, hydronephrosis and vescico-ureteral reflux. These manifestations are representative of the natural history of this condition and should also be searched for in FS survivors.

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

    PubMed

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

    2017-02-06

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

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

    PubMed

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

    2014-02-01

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

  5. 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 %.

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

    PubMed

    Huang, Jirong; Liu, Zhihua; Ruan, Shigui

    2017-03-01

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

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

    PubMed

    Rousselière, Damien; Rousselière, Samira

    2016-01-11

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

  8. 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

  9. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

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

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

    Golub, Mikhail V; Zhang, Chuanzeng

    2015-01-01

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

  13. Ultrasound screening for neoplasms in children up to 6 years old

    PubMed Central

    Jedrzejewski, Grzegorz; Wozniak, Magdalena M.; Pawelec, Agata; Matera, Albert; Kunach, Magdalena; Madej, Tomasz; Wieczorek, Andrzej P.; Nowakowska, Katarzyna

    2016-01-01

    Abstract The aim of the ultrasound (US) screening program was to detect neoplastic lesions in children, together with other pathologies of the developmental age in the area of the neck, abdomen, female pelvis, and scrotum in boys. US screening scans, including cervical, abdominal, pelvical, and scrotal US, were performed in the population of asymptomatic children aged from 9 months to 6 years. The children were scanned in Mobile Pediatric US Unit, consisting of 2 independent consulting rooms. The scans of 14,324 children were analyzed, 7247 boys and 7077 girls. Totally 42,538 US examinations were performed, including 14,187 cervical scans, 14,259 abdominal scans, 6942 female pelvical scans, and 7150 scrotal scans. Totally 5426 abnormalities were detected, which represent 12.7% of all examinations and 30% of patients. Three tumors were recognized, which are renal malignant tumor diagnosed as Wilms tumor, neurogenic tumor of the rib, and teratoma of the testis. US screening in pediatric population can be used to reveal lesions inaccessible to clinical examination, like tumors or other pathologies of developmental age before the onset of clinical symptoms. Due to the large number of detected abnormalities it should be recommended to the whole population of certain age. PMID:27759641

  14. Urologic Diseases in Korean Military Population: a 6-year Epidemiological Review of Medical Records

    PubMed Central

    2017-01-01

    We sought to describe the incidence rate of the urologic disease in the Korean military by reviewing diagnoses made in active duty soldiers from 2008 to 2013. A total of 72,248 first visits were generated in the Defense Medical Statistics Information System (DMSIS) with its gradually increasing trend over 6 years. A sharp increase of first visit was observed after implementation of the regular health check-up for all conscripted soldiers since 2013. Urolithiasis, prostatitis, epididymoorchitis, urethritis, and varicocele were prevalent. Prostatitis was the highest diagnosis made in the outpatient service, while varicocele was ranked the highest in the inpatient service. The incidence rates of urologic disease varied from 12.3 to 34.2 cases per 1,000 person-years. The urologic disease in conscripted men showed different distribution when we separated the population into conscripted and professional soldiers. Epididymoorchitis was the highest disease followed by urolithiasis, dysuresia, and balanoposthitis in 2013. This study underscores that the urologic disease has spent significant amount of health care resources in the Korean military. This calls for further study to find any significant difference and contributing factors of the urologic disease in the military and the civilian population. PMID:27914143

  15. Trends in socioeconomic and nutritional status of children younger than 6 years in India.

    PubMed

    Bharati, Susmita; Pal, Manoranjan; Chakrabarty, Suman; Bharati, Premananda

    2011-05-01

    The main aims of this study are to find out the trends in the (a) prevalence of undernutrition and severe anemia and (b) degree of association of undernutrition and severe anemia in children younger than 6 years in India with some socioeconomic variables. Using the Reproductive and Child Health Survey data, z score of weight for age and hemoglobin status were analyzed to understand the state and agewise variation and their association with the sociodemographic variables through logistic regression. The prevalence of malnutrition according to both the criteria was first seen to increase, attain a maximum value at some age between 12 and 48 months, and then decrease. Statewise distribution showed a close link between the stage of development and the prevalence of malnutrition-prevalence rate being less for developed states. The rates were also less for the Northeastern states of India. The regression analysis clearly points out that children with illiterate mothers, of lower age groups, or from low standard of living households are more prone to become malnourished. The economic growth alone is not sufficient for substantially reducing malnutrition. It is necessary to improve the rate of literacy, especially of women, to reduce the prevalence of malnutrition and anemia among children. It is not only economic development but also overall human development that is needed in India.

  16. Language development and affecting factors in 3- to 6-year-old children.

    PubMed

    Muluk, Nuray Bayar; Bayoğlu, Birgül; Anlar, Banu

    2014-05-01

    The aim of this study was to assess factors affecting language developmental screening test results in 33.0- to 75.0-month-old children. The study group consists of 402 children, 172 (42.8%) boys and 230 (57.2%) girls, aged 33.0-75.0 months who were examined in four age groups: 3 years (33.0-39.0 months), 4 years (45.0-51.0 months), 5 years (57.0-63.0 months) and 6 years (69.0-75.0 months). Demographic data and medical history obtained by a standard questionnaire and Denver II Developmental Test results were evaluated. Maternal factors such as mother's age, educational level, and socioeconomic status (SES) correlated with language items in all age groups. Linear regression analysis indicated a significant effect of mother's education and higher SES on certain expressive and receptive language items at 3 and 4 years. Fine motor items were closely related to language items at all ages examined, while in the younger (3- and 4-year-old) group gross motor items also were related to language development. Maternal and socioeconomic factors influence language development in children: these effects, already discernible with a screening test, can be potential targets for social and educational interventions. The interpretation of screening test results should take into account the interaction between fine motor and language development in preschool children.

  17. Prevalence of Sleep Disorders Among Children 4 - 6 Years Old in Tehran Province, Iran

    PubMed Central

    Ozgoli, Giti; Sheikhan, Zohre; Soleimani, Farin; Nasiri, Malihe; Amiri, Saba

    2016-01-01

    Background Sleep patterns may change over a person’s lifetime; however, the quantity and quality of sleep always depend on individual factors such as age, sex, and psychological and environmental factors. In children, sleep is as important as development. Quantitative sleep problems related to sleep onset and qualitative sleep disorders such as frequent awakenings may lead to insufficient sleep. Objectives This study aimed to assess the prevalence of sleep disorders among children 4 - 6 years old attending the health centers of Shahid Beheshti University of Medical Sciences, Tehran, Iran, in 2013. Patients and Methods This was a cross-sectional study on 400 children selected using a multistage sampling method. Data were collected by interviews. The questionnaire included two sections: a demographic section with questions about the demographic characteristics of the children and parents and a children’s sleep habit questionnaire (CSHQ). Data were analyzed by SPSS 16 and different statistical tests were used (P < 0.05). Results The mean age of the children was 64.27 ± 9.3 months. The prevalence of sleep disorders was 36.25%. Sleep disorders were significantly associated with age, height, body mass index, residence of children, father’s occupation, mother’s diseases, father’s drug abuse, and parents’ marital status (P < 0.05). Conclusions Sleep disorders in children threaten growth and development, and are dangerous for their health. Sleep disorders should be considered in the differential diagnosis of children’s learning and behavioral problems. PMID:27651942

  18. Pesticide poisoning in domestic animals and livestock in Austria: a 6 years retrospective study.

    PubMed

    Wang, Yingzi; Kruzik, Paul; Helsberg, Albert; Helsberg, Inge; Rausch, Wolf-Dieter

    2007-07-04

    A 6 years retrospective study of pesticide poisonings in domestic animals and livestock from 1999 to 2004 submitted to the Institute for Medical Chemistry, University of Veterinary Medicine, Vienna in Austria was compiled and analysed. Totally 380 pesticide analysis requests were referred by veterinary practitioners, from the Institute for Pathology of the above university, by regional and central governments as well as local police departments and district administrations, animal protectionist groups, public health authorities and private clients. Among the total number of suspected samples for pesticides, 175 (46.1%) cases were found positive to contain pesticides of various kinds. Among the pesticides found, carbamate insecticides were most prominent, representing 50.3% of the total positive cases. These compounds were followed by rodenticides-anticoagulants with 18.9% of the positive results, by organophosphate insecticides 5.1%, and by the rodenticides-nonanticoagulant 3.4%, the other 22.3% included molluscicides, herbicides, etc. In totally 225 animals, 123 animals were found positive for pesticide intoxication, among them 47.2% were dogs, 34.1% were cats 9.8% of other species and 8.9% of unspecified animal samples. The pesticides were characterized by HPLC-techniques using commercially available standards. The aim of this Austrian survey was to determine the incidence and frequency of confirmed pesticide intoxications in animals in Austria and to emphasize its relevance in veterinary practice for livestock and domestic animals.

  19. Giant pulmonary artery aneurysm in a 6-year-old child.

    PubMed

    Garg, Gaurav; Tyagi, Himanshu; Agrawal, Gaurav; Anil, S R

    2014-01-01

    A 6-year-old female child was admitted with complaints of progressive dyspnea on exertion since last 3 years. She was saturating 100% on room air with stable vitals. On clinical examination, left precordial bulge was seen with prominent epigastric pulsations. Chest X-ray showed rightward shift of mediastinum and huge homogenous opacity occupying almost entire left lung field. On two-dimensional echocardiography, a large aneurysmal mass was seen occupying left hemithorax which was suspected to be arising from pulmonary artery but its exact site of origin could not be determined. A small patent ductus arteriosus (PDA) was also seen. PDA could be seen directly supplying the aneurysm (Fig. 1). CT angiography was done to confirm the diagnosis. It showed a huge aneurysmal sac measuring 12 cm × 8.9 cm × 14 cm, arising from left pulmonary artery (LPA) opposite to the site of insertion of PDA. Sac was occupying most of the left lung and pushing down the left diaphragm (Fig. 2). Cause of formation of such a huge aneurysm could not be found out. Surgery was performed and mouth of the sac was closed along with ligation of duct, repair of LPA and drainage of the sac. After surgery, lung expansion was good. Patient was discharged and she is doing well.

  20. The development of fine-grained sensitivity to eye contact after 6 years of age.

    PubMed

    Vida, Mark D; Maurer, Daphne

    2012-06-01

    Adults use eye contact as a cue to the mental and emotional states of others. Here, we examined developmental changes in the ability to discriminate between eye contact and averted gaze. Children (6-, 8-, 10-, and 14-year-olds) and adults (n=18/age) viewed photographs of a model fixating the center of a camera lens and a series of positions to the left/right or upward/downward and judged whether the model's gaze was direct or averted to the left/right or upward/downward. The horizontal range of fixation positions leading to the perception of direct gaze (the cone of gaze) was more than 50% larger in 6-year-olds than in adults, but it was adult-like and smaller than the vertical cone of gaze by 8 years of age. The vertical cone of gaze was large and statistically adult-like by age 6, with only a small linear reduction thereafter. In all age groups, the horizontal cone of gaze was centered on the bridge of the participant's nose and the vertical cone was centered slightly below the participant's eye height. These findings indicate that until after age 6, relatively poor sensitivity to direct versus averted gaze limits children's ability to use gaze cues to make social judgments.

  1. The relation between spatial perspective taking and inhibitory control in 6-year-old children.

    PubMed

    Frick, Andrea; Baumeler, Denise

    2016-07-01

    Developmental research on spatial perspective taking has shown that young children are able to solve perspective-taking problems under favorable circumstances, but they have difficulties succeeding in classic tasks involving a conflict between one's own perspective and that of another observer. To date, little is known about the reasons for young children's difficulties in dealing with incongruent perspectives. Based on the assumption that one's own perspective has to be ignored to imagine someone else's perspective, it was investigated whether perspective taking is related to inhibitory control in 6-year-olds (N = 140). An adapted version of the 'Fruit Stroop task', appropriate for preschool children, was used to assess inhibitory control. Perspective taking was assessed using the 'Perspective-Taking Test for Children'. Other spatial and nonspatial abilities were assessed to investigate the specificity of the relation. Results showed a significant correlation between perspective taking and inhibitory control, even when controlled for age, verbal-IQ, and socio-economic status. However, no significant correlations between inhibition and other spatial abilities were found, indicating a specific relation between inhibition and perspective taking. A linear regression analysis showed that, even after accounting for effects of control variables as well as other mental transformation abilities, inhibition accounted for a significant part of the variance in perspective-taking performance. The present findings provide valuable information on what contributes to individual differences in perspective taking, which is an important aspect of everyday cognition and bears relevance for reasoning in technical domains.

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

    PubMed

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

    2017-02-01

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

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

    PubMed Central

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

    2008-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1994-03-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2004-12-01

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

  6. 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.

  7. 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…

  8. [An example of self-evaluation of a sense of achievement by students in 6-year pharmacy school with the model core curriculum of pharmaceutical education].

    PubMed

    Shingaki, Tomoteru; Koyanagi, Jyunichi; Nakamura, Hiroshi; Hirata, Takahiro; Ohta, Atsutane; Akimoto, Masayuki; Shirahata, Akira; Mitsumoto, Atsushi

    2013-01-01

    In March 2012, the first students, finishing the newly introduced 6-year-course of pharmaceutical education, have graduated and gone out into the world. At this point, the Ministry of Education, Culture, Sports, Science and Technology (MEXT) is going to revise the model core curriculum of pharmaceutical education to be more suited for educating students to achieve their goal of becoming the clinical pharmacist standard defined by the revised School Education Act. Here we report the self-evaluation study based on the survey using questionnaire about a sense of achievement with Visual Analog Scales, regarding the fundamental quality as a pharmacist standard proposed by the Professional Activities Committee in the MEXT. The sample size of survey was about 600 of students studying in the Faculty of Pharmaceutical Sciences in Josai International University (JIU) and the survey was carried out during the period of March-April in 2012. The study suggested that the majority of graduates were satisfied with the new education system and marked as a well-balanced quality to be a pharmacist standard, after completing the 6-year pharmaceutical education based on "the model core-curriculum". It would be worthwhile to perform this kind of survey continuously to monitor the student's self-evaluation of a sense of achievement to verify the effectiveness of 6-year-course pharmaceutical education based on the newly establishing core curriculum in Japan.

  9. The Role of Insulin Resistance in Diabetic Neuropathy in Koreans with Type 2 Diabetes Mellitus: A 6-Year Follow-Up Study

    PubMed Central

    Cho, Yu Na; Lee, Kee Ook; Jeong, Julie; Park, Hyung Jun; Kim, Seung-Min; Shin, Ha Young; Hong, Ji-Man; Ahn, Chul Woo

    2014-01-01

    Purpose We previously reported that insulin resistance, low high-density lipoprotein (HDL) cholesterol, and glycaemic exposure Index are independently associated with peripheral neuropathy in Korean patients with type 2 diabetes mellitus. We followed the patients who participated in that study in 2006 for another 6 years to determine the relationship between insulin resistance and neuropathy. Materials and Methods This study involved 48 of the original 86 Korean patients with type 2 diabetes mellitus who were referred to the Neurology clinic for the assessment of diabetic neuropathy from January 2006 to December 2006. These 48 patients received management for glycaemic control and prevention of diabetic complications in the outpatient clinic up to 2012. We reviewed blood test results and the nerve conduction study findings of these patients, taken over a 6-year period. Results Low HDL cholesterol and high triglycerides significantly influenced the development of diabetic neuropathy. Kitt value (1/insulin resistance) in the previous study affected the occurrence of neuropathy, despite adequate glycaemic control with HbA1c <7%. Insulin resistance affected the development of diabetic neuropathy after 6 years: insulin resistance in 2006 showed a positive correlation with a change in sural sensory nerve action potential in 2012. Conclusion Diabetic neuropathy can be affected by previous insulin resistance despite regular glycaemic control. Dyslipidaemia should be controlled in patients who show high insulin resistance because HDL cholesterol and triglycerides are strongly correlated with later development of diabetic neuropathy. PMID:24719137

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

    PubMed

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

    2016-12-08

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

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

    PubMed

    Nam, Kwangho

    2014-10-14

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

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

    PubMed Central

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

    2015-01-01

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

  13. Malnutrition and developmental defects of enamel in 2- to 6-year-old Saudi boys.

    PubMed

    Rugg-Gunn, A J; Al-Mohammadi, S M; Butler, T J

    1998-01-01

    Three hundred and ninety boys aged 2, 4 or 6 years from Riyadh, Saudi Arabia, took part in a survey in 1993/94. The main aims of the study were first, to identify factors related to malnutrition in young children since a study of older children from the same area 1 year before had shown malnutrition to be strongly related to prevalence of developmental defects of enamel (DDE) of permanent teeth and, second, to identify factors related to the prevalence of developmental defects of primary teeth. Enamel defects were recorded by clinical examination of the buccal surfaces of all primary teeth by 1 examiner using the DDE index. A questionnaire to parents provided information on socio-economic status, illness in the mother and child, infant feeding, trauma to teeth and toothbrushing. A 24-hour dietary record, to estimate water and milk intake, and a 24-hour urine collection were obtained for each child twice. Nutritional status was calculated from height for age using WHO methods. Multiple regression analyses revealed four variables related (p<0.05) to malnourished status: low birth-weight, low volume of water drunk, child stopped breast- and bottle-feeding before 1 year of age, and low class urban or rural area of residence. Birth-weight was itself related to area of residence (p = 0.02), parental education (p = 0.02) and maternal illness during pregnancy (p = 0.06). Malnutrition (p<0.001), low birth-weight (p<0.001), childhood illness (p<0.001), brushing of child's teeth (p = 0.003) and swallowing toothpaste (p<0.001) were related to the prevalence of developmental defects of primary teeth. This study indicated several independent variables which may be related to the prevalence of enamel defects in primary and permanent teeth, but longitudinal studies are required to determine which are causes and which are markers of these developmental defects.

  14. 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

  15. 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.

  16. 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

    2016-02-04

    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.

  17. Exploring Within‐tree Architectural Development of Two Apple Tree Cultivars Over 6 Years

    PubMed Central

    COSTES, E.; SINOQUET, H.; KELNER, J. J.; GODIN, C.

    2003-01-01

    The present study addresses the prediction of apple tree development, taking into account both the number and within‐tree position of tree components. The architectural development of two trees per scion cultivar, ‘Fuji’ and ‘Braeburn’, was studied by describing all shoots over 6 years. Flowering and fruiting were observed over 3 years. The description included different scales [entire trees, axes, growth units (GUs) and metamers], and the analysis compared all axes of the trees as a function of their branching order and age. Three main aspects of vegetative development were investigated: the quantity of primary growth; the number and nature of developing axillary shoots; and meristem death. Results confirm the existence of within‐tree morphological gradients, and show that the decrease in growth was comparable in magnitude for all axes and GUs, irrespective of their position. This decrease results from a reduction in the number of metamers per GU, which was modelled by an exponential function. The decrease in growth involved changes in the number and nature of the axillary shoots, which could be described by simple functions. The probability of spur death was constant over the years but differed according to cultivar and type of bearing shoot. The within‐tree probability of flowering and fruiting was predictable for ‘Braeburn’ because axes, regardless of their position and type, had a high probability of flowering and a low probability of fruit set which led to a regular bearing habit. In contrast, ‘Fuji’ had an alternating bearing behaviour that was more complex to predict. This appeared to result from a synchronized increase in the probability that all GUs at tree scale are floral, combined with a high probability of fruit set. The consequences of these results for both yield prediction and architectural simulations are discussed. PMID:12495924

  18. 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

  19. The Pattern of Psoriatic Arthritis in Kashmir: A 6-Year Prospective Study

    PubMed Central

    Rather, Shagufta; Nisa, Nuzhatun; Arif, Tasleem

    2015-01-01

    Background: The prevalence, clinical presentation, and patterns of psoriatic arthritis (PsA) vary in different parts of the world. The scenario of PsA in west is different from that of Asia. Moreover, the oligoarticular type which was considered most prevalent earlier has been replaced by polyarticular type. Aim: The study was to the clinical profile of psoriasis patients associated with PsA in Kashmir valley of India. Materials and Methods: This was a noninterventional, observational, prospective, hospital-based study involving 150 successive patients of PsA over a span of 6 years. Severity of the skin and nail involvement was assessed by Psoriasis Area and Severity Index (PASI) and Nail Psoriasis Severity Index (NAPSI), respectively. PsA was diagnosed by classification criteria for PsA. The number and pattern of swollen and tender joints was counted and classified by Moll and Wright's classification criteria. Results: Plaque-type psoriasis was the most common clinical type, observed in 122 (81.33%) patients followed by erythrodermic psoriasis in 10 (6.66%) patients and pustular psoriasis in eight (5.33%) patients. PsA occurred between 30 and 40 years of age in 105 (70%) patients. The cutaneous involvement occurred before joint involvement in 113 (75.33%), while they occurred simultaneously in 30 (20%) cases and the PsA preceded the skin involvement in seven (4.66%) cases. Symmetrical polyarthritis was the commonest clinical presentation and was seen in 90 (60%) patients. Nail involvement due to psoriasis was present in 120 (80%) patients. Commonest nail change found was pitting and seen in 60 (40%) patients. Conclusion: The clinical pattern of PsA varies in different parts of the world. Knowledge of the clinical presentation of PsA in a given area is necessary for the successful management of this disease. PMID:26417558

  20. 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