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1

Long-term solar activity predictions  

NASA Technical Reports Server (NTRS)

The need for long term solar activity predictions is addressed. The spatial organization of solar activity is described including applications for predictions, and ancient evidence for solar variability. Methods of predicting sunspot numbers are discussed. The inherent accuracy of the methods varies considerably, but a typical error bar 20%. The accuracy of sunspot cycle predictions is considered along with long term predictions of great solar events.

Mcintosh, P. S.; Brown, G. M.; Buhmann, R.; Clark, T.; Fougere, P. F.; Hunter, H.; Lincoln, J. V.; Sargent, H. H., III; Timothy, J. G.; Lin, Y. Z.

1979-01-01

2

Evaluation of long term solar activity effects on GPS performances  

NASA Astrophysics Data System (ADS)

The solar activity hence the solar radiance follows a long term periodic variability with eleven years periodicity, known as solar cycle. This drives the long term variability of the ionosphere. In the present problem we investigate the long term behaviour of the ionosphere with the eleven year cyclic solar activity. Under the present study we characterize the ionospheric variability by Total Electron Content (TEC) taken measurements made by Global Positioning System (GPS) and solar cycle variability by various solar activity indices. We make use of five solar activity indices viz. sunspot number (Rz), solar radio Flux (F10.7 cm), EUV Flux (26-34 nm), flare index and CME occurrences. The long term variability of these solar activity indices were then compared and correlated with the variability of ionospheric TEC, at a mid latitude station, Usuda (36.13N, 138.36E), of Japan, during the solar cycle 23 and ascending phase of cycle 24. From our study, we found that long term changes in the ionospheric TEC vary synchronously with corresponding changes in the solar activity indices. The correlation analysis shows that all the solar activity indices exhibit a very strong correlation with TEC (R =0.76 -0.99). Moreover the correlation between the two is stronger in the descending phase of the solar cycle. The correlation is found to be remarkably strongest during the deep minimum of the solar cycle 24 i.e. between 2007- 2009. Also we noticed a hysteresis effect exists with solar radio flux (F10.7 cm) and solar EUV flux (26-34 nm). This effect is absent with other parameters. Key words: solar Cycle, TEC, Ionosphere, Solar activity

Mansoori, Azad Ahmad; Gwal, Ashok Kumar; Tripathi, Sharad Chandra; Aslam A., M.; Khan, Parvaiz A.; Purohit, Pramod K.; Waheed, Malik Abdul; Bhawre, Purushottam

3

Long-term persistence of solar activity  

NASA Technical Reports Server (NTRS)

We examine the question of whether or not the non-periodic variations in solar activity are caused by a white-noise, random process. The Hurst exponent, which characterizes the persistence of a time series, is evaluated for the series of C-14 data for the time interval from about 6000 BC to 1950 AD. We find a constant Hurst exponent, suggesting that solar activity in the frequency range from 100 to 3000 years includes an important continuum component in addition to the well-known periodic variations. The value we calculate, H approximately 0.8, is significantly larger than the value of 0.5 that would correspond to variations produced by a white-noise process. This value is in good agreement with the results for the monthly sunspot data reported elsewhere, indicating that the physics that produces the continuum is a correlated random process and that it is the same type of process over a wide range of time interval lengths.

Ruzmaikin, Alexander; Feynman, Joan; Robinson, Paul

1994-01-01

4

Long-term control of solar activity on equatorial scintillations  

NASA Astrophysics Data System (ADS)

The Sun has a tremendous influence on the Earth's upper atmosphere. It is not only a source of ionizing radiation but also produces severe disturbances like geomagnetic storms. The 11-year cycle in the variation of behavior and energy output of the Sun influences the generation of equatorial F-region irregularities, which produce scintillations of satellite signals. The phenomenon of scintillations particularly in the L-band has received considerable attention in recent years because of its detrimental effects on communication and navigational systems like GPS. Amplitude scintillations induce signal fading and when the depth of fading exceeds the fade margin of a receiving system, message errors in satellite communication systems are introduced. In GPS, amplitude scintillation may cause degradation of position fixing by standalone GPS receivers, data loss and cycle slips. Severe phase scintillations may stress phase-locked loops in GPS receivers and give rise to loss of phase lock. Scintillation is not a transient phenomenon like the geomagnetic storms but is prevalent mostly during magnetically quiet periods in the pre-midnight hours of equinoctial months of high sunspot number years for a station like Calcutta located near the northern crest of the equatorial anomaly. Amplitude scintillations at L-band (1.5 GHz) and VHF (244 MHz) have been recorded at Calcutta (22.58oN, 88.38oE geographic; 32oN magnetic dip) for more than a solar cycle from geostationary satellites INMARSAT and FLEETSATCOM respectively. The signal-to-noise ratios of GPS L1 (1575.42 MHz) have also been recorded at the same station since 1994. This paper presents a study of L-band scintillations for nearly half a solar cycle (1996-2000) from Calcutta, which is located under the northern anomaly crest in the Indian longitude sector. The variations of occurrence with local time, season, solar and magnetic activity have been discussed to show that solar activity has a very prominent control over development of ionospheric F-region irregularities unlike the transient phenomenon associated with disturbed Sun and geomagnetic storms.

Dasgupta, A.

5

The sunspot cycle no. 24 in relation to long term solar activity variation  

PubMed Central

The solar minimum between solar cycles 23 and 24 during the period 2007–2009 has been the longest and deepest one at least since for the last 100 years. We suggest that the Sun is going to his next supercenturial minimum. The main aim of this paper is to tell about arguments concerning this statement. They are based on series of studies, which have been provided during the period since 1997 up to 2010. The progress of solar cycle 24 since its minimum at the end of 2008 up to the end of October 2011 in the light of long term solar activity dynamics is analyzed.

Komitov, Boris; Kaftan, Vladimir

2013-01-01

6

Long-term Fluctuations in The Earth's Rotation And Solar Activity  

NASA Astrophysics Data System (ADS)

The tidal friction is not the only cause to influence the earth's rotation in long term. There is a correlation between solar activity and long term variations of the Earth's rotation. Possible cause is an interaction between solar wind and magnetosphere of the earth. This would produce the angular deceleration of earth's rotation. Long-term fluctuation in the length of the day (LOD) with semi-amplitude of ca. 4 ms and a period of ca. 1480 years may exist. One cause is probably electromagnetic core-mantle coupling. Ice-rafting event during Holocene is found with cyclity of 1470 years. There is also possible connection between solar activity identified in delta ^14C records of 1450 year periodicity and cyclity of the Earth's rotation. Global-sea level changes associated with climatic variations may produce significant effect on long timescales. The non-tidal acceleration may be connected with the rate of change in Earth's oblateness, attributed to viscous rebound of the Earth from the decrease in load in the polar caps following last deglaciation. The average of Earth's dynamic oblateness (J2 dot) for the past 4000 years is larger than the present J2 (dot) from satellite laser ranging, - 2.8x10^-11/yr. Current increase of LOD is on the average by 1.8+/-0.1 milliseconds per century (ms/ cy). According to early Chinese and Babylonian eclipses from 2000-700 BC we obtain an average of LOD 1.67+/-0.05 ms/cy (1820 AD), which is lower than current value. This is very important for evaluating ancient eclipses before 700 BC. We have used singular spectrum analysis, Catterpilar method, to find periodicities from time series of LOD. We have also founded highly correlated relationship between the periods of low solar activity and LOD at centennial time scales. Our calculation before 700 BC implies sudden change of rotation between 850-750 BC. Major increases of ^14C in the atmosphere at ca. 750 BC (Homer minimum) and ca. 1650 AD (Maunder minimum) are caused by the reduction of the solar activity. A sudden large accumulation of ice at high latitude and a consistent sea-level drop may produce increase of J2 (dot) and an acceleration of earth's rotation before 700 BC.

Banjevic, Boris

2006-08-01

7

Long-term solar-terrestrial observations  

NASA Technical Reports Server (NTRS)

The results of an 18-month study of the requirements for long-term monitoring and archiving of solar-terrestrial data is presented. The value of long-term solar-terrestrial observations is discussed together with parameters, associated measurements, and observational problem areas in each of the solar-terrestrial links (the sun, the interplanetary medium, the magnetosphere, and the thermosphere-ionosphere). Some recommendations are offered for coordinated planning for long-term solar-terrestrial observations.

1988-01-01

8

Validation of Spacecraft Active Cavity Radiometer Total Solar Irradiance (TSI) Long Term Measurement Trends Using Proxy TSI Least Squares Analyses  

NASA Technical Reports Server (NTRS)

Long-term, incoming total solar irradiance (TSI) measurement trends were validated using proxy TSI values, derived from indices of solar magnetic activity. Spacecraft active cavity radiometers (ACR) are being used to measure longterm TSI variability, which may trigger global climate changes. The TSI, typically referred to as the solar constant, was normalized to the mean earth-sun distance. Studies of spacecraft TSI data sets confirmed the existence of a 0.1 %, long-term TSI variability component within a 10-year period. The 0.1% TSI variability component is clearly present in the spacecraft data sets from the 1984-2004 time frame. Typically, three overlapping spacecraft data sets were used to validate long-term TSI variability trends. However, during the years of 1978-1984, 1989-1991, and 1993-1996, three overlapping spacecraft data sets were not available in order to validate TSI trends. The TSI was found to vary with indices of solar magnetic activity associated with recent 10-year sunspot cycles. Proxy TSI values were derived from least squares analyses of the measured TSI variability with the solar indices of 10.7-cm solar fluxes, and with limb-darked sunspot fluxes. The resulting proxy TSI values were compared to the spacecraft ACR measurements of TSI variability to detect ACR instrument degradation, which may be interpreted as TSI variability. Analyses of ACR measurements and TSI proxies are presented primarily for the 1984-2004, Earth Radiation Budget Experiment (ERBE) ACR solar monitor data set. Differences in proxy and spacecraft measurement data sets suggest the existence of another TSI variability component with an amplitude greater than or equal to 0.5 Wm-2 (0.04%), and with a cycle of 20 years or more.

Lee, Robert Benjamin, III; Wilson, Robert S.

2003-01-01

9

On the high correlation between long-term averages of solar wind speed and geomagnetic activity  

NASA Technical Reports Server (NTRS)

Six-month and yearly averages of solar-wind speed from 1962 to 1975 are shown to be highly correlated with geomagnetic activity as measured by averages of the Ap index. On the same time scale the correlation between the southward component of the interplanetary magnetic field and geomagnetic activity is poor. Previous studies with hourly averages gave opposite results. The better correlation with the southward component on an hourly time scale is explained by its large variation compared with the relatively constant solar-wind speed. However, on a yearly time scale the magnitude of the variations in both parameters are about the same. This problem can be solved by invoking an energy transfer mechanism which is proportional to the first power of the southward component and a higher power of the solar-wind speed.

Crooker, N. U.; Feynman, J.; Gosling, J. T.

1977-01-01

10

Simulation of Long-term Changes in the Surface Ozone and Aerosol Concentrations Based on the Solar Activity Data  

NASA Astrophysics Data System (ADS)

Based on the long-term data obtained during previous studies we have found an interrelationship the surface ozone and aerosol content with solar activity. Variation of the concentration of both these atmospheric components have a period close to 11 years that has a 2(3)-year phase lag with respect to solar activity. Analyzing possible causes of such behaviour we discarded hypotheses of the anthropogenic origin of the trend and post-volcanic influence of El Chichon and Penatubo eruptions. It turned out, that variation of aerosol number concentration correlates with atmospheric circulation forms (W, E, and C), which are governed by solar activity. Then we analysed sequentially an ozone mechanism and variations of incoming ultraviolet radiation to determine possible causes of this phenomenon. As a result we found an intermediate process, which consists in the influence of increasing UV radiation on plants. At the beginning of UV radiation increase it is observed suppression of the vegetation. After 1- or 2-year adaptation period its productivity becomes stronger that leads to the emission of additional amount of ozone and aerosol precursors. This hypothesis has been verified using Normalized Difference Vegetation Index (NDVI) and gave good results. Prediction of the long-term changes in the surface ozone and aerosol concentrations has been done based on this hypothesis. This work was funded by Presidium of RAS (Program No. 16), Brunch of Geology, Geophysics and Mining Sciences of RAS (Program No 5), Russian Foundation for Basic Research (grant No 08-05-92499), and Federal Agency for Science and Innovation (State Contract ? 02.518.11.7153).

Belan, Boris; Antokhin, Pavel; Arshinov, Mikhail; Belan, Sergey; Slyadneva, Tatyana; Tolmachev, Gennadii

2010-05-01

11

Long term solar activity and ionospheric prediction services rendered by the National Physical Laboratory, New Delhi  

NASA Technical Reports Server (NTRS)

The data base used in solar and ionospheric prediction services is described. Present prediction techniques are discussed and compared with actual observations. Future prediction techniques using computers are also discussed.

Reddy, B. M.; Aggarwal, S.; Lakshmi, D. R.; Shastri, S.; Mitra, A. P.

1979-01-01

12

Large-scale horizontal flows in the solar photosphere II: Long-term behaviour and magnetic activity response  

E-print Network

Recently, we have developed a method useful for mapping large-scale horizontal velocity fields in the solar photosphere. The method was developed, tuned and calibrated using the synthetic data. Now, we applied the method to the series of Michelson Doppler Imager (MDI) dopplergrams covering almost one solar cycle in order to get the information about the long-term behaviour of surface flows. We have found that our method clearly reproduces the widely accepted properties of mean flow field components, such as torsional oscillations and a pattern of meridional circulation. We also performed a periodic analysis, however due to the data series length and large gaps we did not detect any significant periods. The relation between the magnetic activity influencing the mean zonal motion is studied. We found an evidence that the emergence of compact magnetic regions locally accelerates the rotation of supergranular pattern in their vicinity and that the presence of magnetic fields generally decelerates the rotation in the equatorial region. Our results show that active regions in the equatorial region emerge exhibiting a constant velocity (faster by 60 +/- 9 m/s than Carrington rate) suggesting that they emerge from the base of the surface radial shear at 0.95 R_sun, disconnect from their magnetic roots, and slow down during their evolution.

Michal Svanda; Mirek Klvana; Michal Sobotka; Vaclav Bumba

2007-10-14

13

Long-term variations in the north-south asymmetry of solar activity and solar cycle prediction, III: Prediction for the amplitude of solar cycle 25  

NASA Astrophysics Data System (ADS)

The combined Greenwich and Solar Optical Observing Network (SOON) sunspot group data during 1874-2013 are analysed and studied the relatively long-term variations in the annual sums of the areas of sunspot groups in 0°-10°, 10°-20°, and 20°-30° latitude intervals of the Sun’s northern and southern hemispheres. The variations in the corresponding north-south differences are also studied. Long periodicities in these parameters are determined from the fast Fourier transform (FFT), maximum entropy method (MEM), and Morlet wavelet analysis. It is found that in the difference between the sums of the areas of the sunspot groups in 0°-10° latitude intervals of northern and southern hemispheres, there exist ?9-year periodicity during the high activity period 1940-1980 and ?12-year periodicity during the low activity period 1890-1939. It is also found that there exists a high correlation (85% from 128 data points) between the sum of the areas of the sunspot groups in 0°-10° latitude interval of the southern hemisphere during a Qth year (middle year of 3-year smoothed time series) and the annual mean International Sunspot Number (RZ) of (Q+9)th year. Implication of these results is discussed in the context of solar activity prediction and predicted 50±10 for the amplitude of solar cycle 25, which is about 31% lower than the amplitude of cycle 24.

Javaraiah, J.

2015-01-01

14

Interhourly variability index of geomagnetic activity and its use in deriving the long-term variation of solar wind speed  

NASA Astrophysics Data System (ADS)

We describe the detailed derivation of the interhourly variability (IHV) index of geomagnetic activity. The IHV index for a given geomagnetic element is mechanically derived from hourly values or means as the sum of the unsigned differences between adjacent hours over a 7-hour interval centered on local midnight. The index is derived separately for stations in both hemispheres within six longitude sectors spanning the Earth using only local night hours. It is intended as a long-term index and available data allows derivation of the index back well into the 19th century. On a timescale of a 27-day Bartels rotation, IHV averages for stations with corrected geomagnetic latitude less than 55° are strongly correlated with midlatitude range indices (R2 = 0.96 for the am index since 1959; R2 = 0.95 for the aa index since 1980). We find that observed yearly averages of aa before the year 1957 are ˜3 nT too small compared to values calculated from IHV using the regression constants based on 1980-2004. We interpret this discrepancy as an indication that the calibration of the aa index is in error before 1957. There is no systematic discrepancy between observed and similarly calculated ap values back to 1932. Bartels rotation averages of IHV are also strongly correlated with solar wind parameters (R2 = 0.79 with BV2). On a timescale of a year combining the IHV index (giving BV2 with R2 = 0.93) and the recently developed interdiurnal variability (IDV) index (giving interplanetary magnetic field magnitude, B, with R2 = 0.74) allows determination of solar wind speed, V, from 1890 to present. Over the ˜120-year series, the yearly mean solar wind speed varied from a low (inferred) of 303 km/s in 1902 to a high (observed) value of 545 km/s in 2003. The calculated yearly values of the product BV using B and V separately derived from IDV and IHV agree quantitatively with (completely independent) BV values derived from the amplitude of the diurnal variation of the horizontal component in the polar caps since 1926 (and sporadically further back).

Svalgaard, Leif; Cliver, Edward W.

2007-10-01

15

Going Solar Yields Long-Term Economical, Educational Benefits  

ERIC Educational Resources Information Center

Going solar is not an easy decision, but a long-term investment with a potentially substantial up-front cost. While some schools have enough capital in reserve, can raise bond money, or can solicit sufficient donations, many schools rely on creative financial programs to make a solar energy system economically feasible. Thinking about going solar

von Moos, Brian

2009-01-01

16

Long term performance prediction of residential solar energy heating systems  

Microsoft Academic Search

An automated technique to provide long term performance predictions of residential solar energy heating systems has been developed. Implementation of this interactive computer program requires inputs of generic system description, operational site characteristics, subsystem characteristics, application characteristics, and modifications (if any) to baseline generic design factors. With these inputs, either as single values or iterated over ranges of characteristics, the

J. M. Nash; J. C. Bartlett; N. J. Caiola; J. E. Irby

1976-01-01

17

Possible associations between long term anomalous geomagnetic variations, Vrancea (Romania) intermediate depths earthquakes and the solar activity for the last 15 years  

NASA Astrophysics Data System (ADS)

Geomagnetic variations associated with earthquakes are widely accepted and several anomalous geomagnetic observations have been interpreted as a result of changing rock magnetic properties under varying tectonic stress (piezomagnetic effect). During the last 15 years of geomagnetic investigations conducted in Vrancea seismogenic zone, period covering more than a complete solar cycle, the solar-terrestrial perturbations have fluctuated from very low to very large values, providing the ideal medium to observe the correlation between the long and short term geomagnetic field perturbations, solar activity and earthquakes. The October 2004 intermediate depth earthquake (Mw=6.0) offered us the opportunity to investigate possible connections between the local geomagnetic field behavior and the occurrence of moderate magnitude Vrancea earthquakes. The comparison between the geomagnetic data obtained at a station inside the epicentral zone with other remote reference stations (outside the epicenter) considers an effective technique to detect the anomalous variation of a lithospheric origin. The working data are: (i) the geomagnetic field records made at Muntele Rosu Observatory (MLR), Surlari (SUA) and/or Tihany (THY) INTERMAGNET Observatories; (ii) the seismic data for Vrancea source zone; (iii) the daily geomagnetic index from NOAA/Space Weather. The one minute and daily averaged geomagnetic data were calculated at these stations for the whole period 1996-2011. The geomagnetic components: X, Y (horizontal North-South and East-West) and Z (vertical) and the normalized vertical component (Bz/Bx and Bz/By) were used in the data analysis processes and also in the comparison of the geomagnetic data between the selected stations. Our results indicate the presence of long term anomalous variations (weeks or months) in the geomagnetic components and in the magnetic impedance at MLR Observatory (close to the epicenter) and no magnetic modifications in the SUA and THY recordings (far from the epicenter) preceding the occurrence of earthquakes with Mw>4.0. Moreover, in the periods of anomalous behavior, the geomagnetic components recorded at MLR show no correlation with those recorded at the other two stations, as they do in the rest of the time. The observed anomalous variations may be explained as a result of the tectonic stress variations and the enhancement of the lithospheric conductivity in the Vrancea region during the preparation period of earthquakes.

Moldovan, I. A.; Moldovan, A. S.; Placinta, A. O.; Takla, E. M.; Constantin, A. P.; Popescu, E.

2012-04-01

18

Long-term Periodicity Variations of the Solar Radius  

NASA Astrophysics Data System (ADS)

In order to study the long-term periodicity variations of the solar radius, daily solar radius data from 1978 February to 2000 September at the Calern Observatory are used. Continuous observations of the solar radius are difficult due to the weather, seasonal effects, and instrument characteristics. Thus, to analyze these data, we first use the Dixon criterion to reject suspect values, then we measure the cross-correlation between the solar radius and sunspot numbers. The result indicates that the solar radius is in complete antiphase with the sunspot numbers and shows lead times of 74 months relative to the sunspot numbers. The Lomb-Scargle and date compensated discrete Fourier transform methods are also used to investigate the periodicity of the solar radius. Both methods yield similar significance periodicities around ~1 yr, ~2.6 yr, ~3.6 yr, and ~11 yr. Possible mechanisms for these periods are discussed. The possible physical cause of the ~11 yr period is the cyclic variation of the magnetic pressure of the concentrated flux tubes at the bottom of the solar convection zone.

Qu, Z. N.; Xie, J. L.

2013-01-01

19

LONG-TERM PERIODICITY VARIATIONS OF THE SOLAR RADIUS  

SciTech Connect

In order to study the long-term periodicity variations of the solar radius, daily solar radius data from 1978 February to 2000 September at the Calern Observatory are used. Continuous observations of the solar radius are difficult due to the weather, seasonal effects, and instrument characteristics. Thus, to analyze these data, we first use the Dixon criterion to reject suspect values, then we measure the cross-correlation between the solar radius and sunspot numbers. The result indicates that the solar radius is in complete antiphase with the sunspot numbers and shows lead times of 74 months relative to the sunspot numbers. The Lomb-Scargle and date compensated discrete Fourier transform methods are also used to investigate the periodicity of the solar radius. Both methods yield similar significance periodicities around {approx}1 yr, {approx}2.6 yr, {approx}3.6 yr, and {approx}11 yr. Possible mechanisms for these periods are discussed. The possible physical cause of the {approx}11 yr period is the cyclic variation of the magnetic pressure of the concentrated flux tubes at the bottom of the solar convection zone.

Qu, Z. N.; Xie, J. L. [National Astronomical Observatories/Yunnan Astronomical Observatory, Chinese Academy of Sciences, Kunming, Yunnan 650011 (China)] [National Astronomical Observatories/Yunnan Astronomical Observatory, Chinese Academy of Sciences, Kunming, Yunnan 650011 (China)

2013-01-01

20

Montessori-Based Dementia Activities in Long-Term Care  

Microsoft Academic Search

This article describes Montessori-based activities for use with persons with dementia in long-term care settings. An overview of the Montessori method of education is presented, with emphasis on its application to geriatric populations. Individual and group activities are detailed, along with techniques for adapting Montessori materials and procedures for use in long-term care settings. A description is provided of training

Silvia Orsulic-Jeras; Nicole M. Schneider; Cameron J. Camp; Pam Nicholson; Michael Helbig

2001-01-01

21

Long-term memories in online users' selecting activities  

NASA Astrophysics Data System (ADS)

In this paper, we investigate the long-term memory effect in the behavior of online users. Two user-oriented online movie systems are used in this study. Due to the short length of the series, the balanced estimation of diffusion entropy approach is used to evaluate scaling-invariance in selecting activities of users in the two online movie systems. Our results indicate that persistence (long-term memory) exists widely in the movie selecting series. However, there is generally significant difference between a user's objective and subjective behaviors. Additionally, statistically, the long-term memory depends on activity levels, as results show that the much more active a users' group, the stronger the long-term memory will be. These findings provide a new criterion for constructing reasonable models, and can help understand how individuals' behaviors form a collective behavior of an online society.

Pan, Xue; Hou, Lei; Stephen, Mutua; Yang, Huijie

2014-07-01

22

Evidence of a long-term trend in total solar irradiance  

NASA Astrophysics Data System (ADS)

Aims: During the solar minimum of 2008, the value of total solar irradiance at 1 AU (TSI) was more than 0.2 Wm-2 lower than during the last minimum in 1996, indicating for the first time a directly observed long-term change. On the other hand, chromospheric indices and hence solar UV irradiance do not exhibit a similar change. Methods: Comparison of TSI with other activity parameters indicates that only the open solar magnetic field, BR, observed from satellites at 1 AU show a similar long-term behaviour. The values at the minima correlate well and the linear fit provides a direct physical relationship between TSI and BR during the minimum times. Results: This correlation allows an unambiguous reconstruction of TSI back in time, provided the open solar magnetic field can be determined from e.g. geomagnetic indices or cosmogenic radionucleides. Since the solar UV irradiance has no long-term trend, the mechanism for the secular change of TSI must differ from the effect of surface magnetism, as manifested by sunspots, faculae, and network which indeed explain well the intra-cycle variability of both total and spectral irradiance. Conclusions: The long-term trend of TSI is most probably caused by a global temperature change of the Sun that does not influence the UV irradiance in the same way as the surface magnetic fields. Appendix is only available in electronic form at http://www.aanda.org

Fröhlich, C.

2009-07-01

23

Long-term downward trend in total solar irradiance.  

PubMed

The first 5 years (from 1980 to 1985) of total solar irradiance observations by the first Active Cavity Radiometer Irradiance Monitor (ACRIM I) experiment on board the Solar Maximum Mission spacecraft show a clearly defined downward trend of -0.019% per year. The existence of this trend has been confirmed by the internal self-calibrations of ACRIM I, by independent measurements from sounding rockets and balloons, and by observations from the Nimbus-7 spacecraft. The trend appears to be due to unpredicted variations of solar luminosity on time scales of years, and it may be related to solar cycle magnetic activity. PMID:17778952

Willson, R C; Hudson, H S; Frohlich, C; Brusa, R W

1986-11-28

24

Uncovering Camouflage: Amygdala Activation Predicts Long-Term Memory  

E-print Network

Neuron Article Uncovering Camouflage: Amygdala Activation Predicts Long-Term Memory of Induced (``camouflage''), followed by brief exposures to the original images (``solution''), which led to induced as ``remembered'' if detailed perceptual knowledge was elicited from the camouflage image alone. During encoding

Rubin, Nava

25

Speculated Long-Term Trends in Solar Irradiance and Their Implications for the Future  

NASA Astrophysics Data System (ADS)

Solar irradiance varies in response to changes in solar magnetism. Enhanced emission in faculae is a primary source of total irradiance variability. Bright chromospheric plages and network overlying photospheric faculae are dominant sources of variations in UV irradiance that affect ozone, and in strong EUV emission lines that impact neutral and ionized densities in the upper atmosphere. Knowledge of the sources of long-term trends in solar irradiance is important for specifying the Sun's role in global change and space weather, in the past and in the future. Neither irradiance nor the chromospheric Ca and Mg indices that are sensitive indicators of bright emission sources, was monitored prior to 1976 so scenarios for their long-term variability must be developed indirectly. One approach utilizes the range of variability evident in Ca emission in Sun-like stars; another correlates measured solar fluxes with historical proxies of solar activity, such as the aa index. The amplitudes of long-term total solar irradiance variability estimated by these two independent approaches agree quite well. But irradiances reconstructed from smoothed group sunspot numbers increase primarily in the first part of the twentieth century and lack a significant long-term rising trend in their cycle minima in the past 50 years, such as is inferred from geomagnetic indices. The historical reconstructions, though speculative, provide a basis for assessing future solar irradiance trends. Progress in specifying the sources of long-term solar irradiance trends requires new understanding of how the closed flux associated with bright magnetic sources in the solar atmosphere relates to the open flux associated primarily with coronal holes. The closed flux produces irradiance variations whereas the open flux extends into the heliosphere, modulates the interplanetary magnetic field and produces geomagnetic activity. Initial results based on potential field extrapolations show that the emergence of new active regions together with flux transport processes continually alter the relative amounts of open and closed flux. Whether or not closed and open flux evolve differently or together over long time scales is presently unknown but is essential for determining the physical relevance of geomagnetic indices for inferring historical solar irradiance variations.

Lean, J. L.; Wang, Y.

2001-05-01

26

Long-Term Solar Cycle Effects on the Ion Escape from Mars  

NASA Astrophysics Data System (ADS)

The planetary ion escape rate from Mars is solar cycle dependent. During the recent transition from cycle 23 to cycle 24, the escape rate increased by a factor of 10, from 1·1024 s-1 (solar minimum) to 1·1025 s-1 (solar maximum) (Lundin et al., 2013). A regression analysis gives a high correlation between ion escape fluxes and the monthly averaged solar activity proxies F10.7 and Ri (sunspot number). Furthermore, there is a high correlation (0.89) between the monthly F10.7 and Ri, i.e. both proxies are related to the same phenomena, most likely the solar magnetic flux. Similarly, the concentration of radiogenic isotopes in the Earth's atmosphere is controlled by the solar-heliospheric magnetic flux, i.e. the concentration of radiogenic isotopes (e.g. C14 and Be10) can also be used as proxies for the solar magnetic flux. Radiogenic isotopes therefore offers another means to model the long-term ion escape, C14 data going back in time by 12 000 years. From a regression analysis of the relation between C14 and Ri, the empiric model can now be applied to derive Martian ion escape rates much further back in time, compared to that achieved using historic Ri data records (1700 years). Notice that the model does not account for geological and atmospheric effects that may significantly vary on a long-term basis. Furthermore, the model cannot describe short-term effects caused by episodic solar events. Nevertheless, the model may serve as a useful tool to describe long-term effects of solar cycle activity on the Martian atmosphere and ionosphere. References Lundin, R., S.Barabash, M. Holmström, et al., Solar cycle effects on the ion escape from Mars, Geophys. Res Lett., 40, 6028-6032. 2013

Lundin, Rickard; Barabash, Stas; Yamauchi, Masatoshi; Lundstedt, Henrik

2014-05-01

27

Long-term variations in total solar irradiance  

NASA Technical Reports Server (NTRS)

For more than a decade total solar irradiance has been monitored simultaneously from space by different satellites. The detection of total solar irradiance variations by satellite-based experiments during the past decade and a half has stimulated modeling efforts to help identify their causes and to provide estimates of irradiance data, using `proxy' indicators of solar activity, for time intervals when no satellite observations exist. In this paper total solar irradiance observed by the Nimbus-7/Earth Radiation Budget (ERB), Solar Maximum Mission (SMM)/Active Cavity Radiometer Irradiance Monitor (ACRIM) 1, and Upper Atmosphere Research Satellite (UARS)/ACRIM 2 radiometers is modeled with the Photometric Sunspot Index and the Mg II core-to-wing ratio. Since the formation of the Mg II line is very similar to that of the Ca II K line, the Mg core-to-wing ratio, derived from the irradiance observations of the Nimbus-7 and NOAA9 satellites, is used as a proxy for the bright magnetic elements. It is shown that the observed changes in solar irradiance are underestimated by the proxy models at the time of maximum and during the beginning of the declining portion of solar cycle 22 similar to behavior just before the maximum of solar cycle 21. This disagreement between total irradiance observations and their model estimates is indicative of the fact that the underlying physical mechanism of the changes observed in the solar radiative output is not well-understood. Furthermore, the uncertainties in the proxy data used for irradiance modeling and the resulting limitation of the models should be taken into account, especially when the irradiance models are used for climatic studies.

Pap, Judit M.; Willson, Richard C.; Froelich, Claus; Donnelly, Richard F.; Puga, Larry

1994-01-01

28

Long-Term Solar Cycle Effects on the Ion Escape from Mars  

NASA Astrophysics Data System (ADS)

The planetary ion escape rate from Mars is solar cycle dependent. During the recent transition from cycle 23 to cycle 24, the escape rate increased by a factor of 10, from 1·1024 s-1 (solar minimum) to 1·1025 s-1 (solar maximum) [1]. A regression analysis gives a high correlation between ion escape fluxes and the monthly averaged solar activity proxies F10.7 and sunspot number Ri (Fig. 1). Furthermore, there is a high correlation (0.89) between the monthly F10.7 and Ri, i.e. both proxies are related to the same phenomena, most likely the solar magnetic flux. Similarly, the concentration of radiogenic isotopes in the Earth's atmosphere is controlled by the solar-heliospheric magnetic flux, i.e. the concentration of radiogenic isotopes (e.g. C14 and Be10) can also be used as proxies for the solar magnetic flux. Radiogenic isotopes therefore offers another means to model the long-term ion escape, C14 data going back in time by 12 000 years. From a regression analysis of the relation between C14 and Ri, the empiric model can now be applied to derive Martian ion escape rates much further back in time (Fig. 2), compared to that achieved using historic Ri data records (1700 years). Notice that the model does not account for geological and atmospheric effects that may significantly vary on a long-term basis. Furthermore, the model cannot describe short-term effects caused by episodic solar events. Nevertheless, the model may serve as a useful tool to describe long-term effects of solar cycle activity on the Martian atmosphere and ionosphere.

Lundin, R.; Barabash, S.; Yamauchi, M.; Lundstedt, H.

2014-04-01

29

Ethically Managing Sexual Activity in Long-term Care  

Microsoft Academic Search

Although care providers in almost every long-term care facility face daily challenges involving issues related to residents’\\u000a sexual lives, guidelines for the ethical, legal and socially responsible management of sexual activity are rare and ubiquitously\\u000a inadequate. In this essay, I argue that ethically and legally, care providers should only interfere in residents’ sexual activity\\u000a in restricted ways and for limited

Bethan Everett

2007-01-01

30

TOWARDS AN IMPROVED HIGH RESOLUTION GLOBAL LONG-TERM SOLAR RESOURCE DATABASE  

E-print Network

TOWARDS AN IMPROVED HIGH RESOLUTION GLOBAL LONG- TERM SOLAR RESOURCE DATABASE Paul W. Stackhouse and test an improved production system that will enable the longest-term global solar resource database

Perez, Richard R.

31

Long-term variability of solar magnetic-fields  

NASA Astrophysics Data System (ADS)

Studies of the variations of the solar magnetic field are reviewed. Consideration is given to the study of 600 Myr-old Australiain varve data showing the 22-yr magnetic cycle and variations with 300-400 yr periods (Williams, 1981 and Bracewell, 1985). Methods of interpreting the organization of large-scale solar field patterns are discussed. Other studies examined include the interpretation of modal structure in the photospheric field by Stenflo et al. (1988), and the study of Sheeley et al. (1987) showing that much of the large-scale surface pattern can be deduced from the measured emerging flux.

Hoeksema, J. Todd; Scherrer, P. H.

32

Long-term activity recognition from wristwatch accelerometer data.  

PubMed

With the development of wearable devices that have several embedded sensors, it is possible to collect data that can be analyzed in order to understand the user's needs and provide personalized services. Examples of these types of devices are smartphones, fitness-bracelets, smartwatches, just to mention a few. In the last years, several works have used these devices to recognize simple activities like running, walking, sleeping, and other physical activities. There has also been research on recognizing complex activities like cooking, sporting, and taking medication, but these generally require the installation of external sensors that may become obtrusive to the user. In this work we used acceleration data from a wristwatch in order to identify long-term activities. We compare the use of Hidden Markov Models and Conditional Random Fields for the segmentation task. We also added prior knowledge into the models regarding the duration of the activities by coding them as constraints and sequence patterns were added in the form of feature functions. We also performed subclassing in order to deal with the problem of intra-class fragmentation, which arises when the same label is applied to activities that are conceptually the same but very different from the acceleration point of view. PMID:25436652

Garcia-Ceja, Enrique; Brena, Ramon F; Carrasco-Jimenez, Jose C; Garrido, Leonardo

2014-01-01

33

Long-Term Activity Recognition from Wristwatch Accelerometer Data *  

PubMed Central

With the development of wearable devices that have several embedded sensors, it is possible to collect data that can be analyzed in order to understand the user's needs and provide personalized services. Examples of these types of devices are smartphones, fitness-bracelets, smartwatches, just to mention a few. In the last years, several works have used these devices to recognize simple activities like running, walking, sleeping, and other physical activities. There has also been research on recognizing complex activities like cooking, sporting, and taking medication, but these generally require the installation of external sensors that may become obtrusive to the user. In this work we used acceleration data from a wristwatch in order to identify long-term activities. We compare the use of Hidden Markov Models and Conditional Random Fields for the segmentation task. We also added prior knowledge into the models regarding the duration of the activities by coding them as constraints and sequence patterns were added in the form of feature functions. We also performed subclassing in order to deal with the problem of intra-class fragmentation, which arises when the same label is applied to activities that are conceptually the same but very different from the acceleration point of view. PMID:25436652

Garcia-Ceja, Enrique; Brena, Ramon F.; Carrasco-Jimenez, Jose C.; Garrido, Leonardo

2014-01-01

34

Long term variability of the solar wind speed  

NASA Technical Reports Server (NTRS)

We have reviewed the solar wind data obtained over a period of more than three decades. The data coverage on the Omnitape begins on 27 November 1963 and ends on 31 December 1993, for the version used by us. The coverage is very uneven, ranging from less than 40% to greater than 80%. We find that a correlation continues to exist between the measured values of the solar wind speed (V) and the geomagnetic index Ap. For the period when the coverage is greater than or equal to 85%, the data fit the equation: V (km/s) = 11.7 A(sub p) + 260. The correlation coefficient is 0.8, at a confidence level of 99.95%. However, we find that the predicted value of V may differ from the observed value by as much as 15% for a year in which the coverage is poorer. A comparison of IMP 8 with Pioneer Venus Orbiter (PVO) data indicates that the average values at the former are systematically higher by as much as 35 km/s (approximately 8%) for an overlapping time period. Also, we draw attention to the observed three solar cycle periodicity in A(sub p) data for the 1932 to 1994 period and its implications for forecasting the parameters for solar cycle 23 as well as on the computations of the modulation parameters for cosmic rays.

Gazis, P. R.; Ahluwalia, H. S.; Fikani, M. M.; Xue, S. .S.

1995-01-01

35

Long-Term Variability of the Polytropic Index of Solar Wind Protons at 1 AU  

NASA Astrophysics Data System (ADS)

Spacecraft data from the OMNI database were used to calculate the value of the polytropic index of the solar wind by fitting the logarithms of proton density and temperature in selected time intervals from 1 January 1995 to 30 June 2012. Bernoulli's integral and the correlation coefficient were used to filter the results. An alternative method based on the maximization of the correlation coefficient was employed to confirm our results. The long-term behavior of the polytropic index we obtained is found to be virtually identical for both methods. We noticed a characteristic behavior of the estimated polytropic index values, particularly from 1995 to 2006, which tends to have a periodicity of about one year. The distribution of the polytropic index is best described by a ?-Gaussian distribution with mean ? 1.8 and standard deviation ? 2.4. We finally examined the possible correlation between the polytropic index values and solar activity.

Nicolaou, G.; Livadiotis, G.; Moussas, X.

2014-04-01

36

Long-term eruptive activity at a submarine arc volcano  

USGS Publications Warehouse

Three-quarters of the Earth's volcanic activity is submarine, located mostly along the mid-ocean ridges, with the remainder along intraoceanic arcs and hotspots at depths varying from greater than 4,000 m to near the sea surface. Most observations and sampling of submarine eruptions have been indirect, made from surface vessels or made after the fact. We describe here direct observations and sampling of an eruption at a submarine arc volcano named NW Rota-1, located 60 km northwest of the island of Rota (Commonwealth of the Northern Mariana Islands). We observed a pulsating plume permeated with droplets of molten sulphur disgorging volcanic ash and lapilli from a 15-m diameter pit in March 2004 and again in October 2005 near the summit of the volcano at a water depth of 555 m (depth in 2004). A turbid layer found on the flanks of the volcano (in 2004) at depths from 700 m to more than 1,400 m was probably formed by mass-wasting events related to the eruption. Long-term eruptive activity has produced an unusual chemical environment and a very unstable benthic habitat exploited by only a few mobile decapod species. Such conditions are perhaps distinctive of active arc and hotspot volcanoes. ?? 2006 Nature Publishing Group.

Embley, R.W.; Chadwick, W.W., Jr.; Baker, E.T.; Butterfield, D.A.; Resing, J.A.; De Ronde, C. E. J.; Tunnicliffe, V.; Lupton, J.E.; Juniper, S.K.; Rubin, K.H.; Stern, R.J.; Lebon, G.T.; Nakamura, K.-I.; Merle, S.G.; Hein, J.R.; Wiens, D.A.; Tamura, Y.

2006-01-01

37

The long-term dynamical evolution and stability of the solar system  

Microsoft Academic Search

The question of the long-term stability of the solar system is one of the oldest unsolved problems in Newtonian physics. Although the general solution remains elusive, several recent theoretical and numerical advances suggest that the simple 'clockwork' model of the solar system envisaged by early workers must be replaced by one incorporating the deterministic chaos recently found in many nonlinear

Martin J. Duncan; Thomas Quinn

1993-01-01

38

Future Long-term Measurements of Solar Spectral Irradiance Variability: Achievements and Lessons from the SORCE SIM  

NASA Astrophysics Data System (ADS)

In order to advance understanding of how natural and anthropogenic process affect Earth’s climate system there is a strong scientific importance of maintaining accurate, long-term records of climate forcing. The continuation of solar spectral irradiance (SSI) measurements are needed to characterize poorly understood wavelength dependent climate processes. A major challenge quantifying the influence of SSI variability relates directly to the radiometric absolute accuracy and long-term precision of the measurements. The strong reliance on radiative transfer modeling for interpretation and quantification of the deposition of solar radiation in the atmosphere makes it imperative that the spectral distribution of radiant energy entering the atmosphere be known to a high degree of absolute accuracy (tied directly to international standards). The Spectral Irradiance Monitor (SIM) is a solar spectral radiometer that continuously monitors the SSI across the wavelength region spanning the ultraviolet, visible and near infrared (200 nm - 2400 nm, a region encompassing 96% of the total solar irradiance). A future SIM instrument is included as part of the Total and Spectral Solar Irradiance Sensor (TSIS) to continue the measurement of SSI, which began with the SOlar Radiation and Climate Experiment (SORCE), launched in 2003. SORCE SIM measurements have now monitored SSI for a sufficiently long time and over a wide range in solar activity to quantify wavelength-dependent variability form the UV to the near IR. The analysis of the SORCE SIM measurements of solar spectral variability have resulted in a number of instrument design refinements central to maintaining the long-term calibration to SI irradiance standards and achieve the necessary measurement precision and long-term reproducibility (0.05-0.01% per year) to meet the needs for establishing a climate record of solar spectral irradiance into the future.

Richard, E. C.; Harder, J. W.; Pilewskie, P.; Woods, T. N.; Lykke, K.; Brown, S.

2010-12-01

39

Towards an Improved High Resolution Global Long-Term Solar Resource Database  

NASA Technical Reports Server (NTRS)

This paper presents an overview of an ongoing project to develop and deliver a solar mapping processing system to the National Renewable Energy Laboratory (NREL) using the data sets that are planned for production at the National Climatic Data Center (NCDC). NCDC will be producing a long-term radiance and cloud property data set covering the globe every three hours at an approximate resolution of 10 x 10 km. NASA, the originators of the Surface meteorology and Solar Energy web portal are collaborating with SUNY-Albany to develop the production system and solar algorithms. The initial result will be a global long-term solar resource data set spanning over 25 years. The ultimate goal of the project is to also deliver this data set and production system to NREL for continual production. The project will also assess the impact of providing these new data to several NREL solar decision support tools.

Stackhouse, Paul W.; Cox, Stephen J.; Chandler, William S.; Hoell, James M.; Zhang, Taiping; Westburg, David J.; Perez, Richard; Hemker, Charles; Schlemmer, James; Renne, D.; Sengupta, Manajit; Bates, John J.; Knapp, Kenneth

2011-01-01

40

Long-term middle atmospheric influence of very large solar proton events  

E-print Network

Long-term middle atmospheric influence of very large solar proton events Charles H. Jackman,1 ozone change in these years were not statistically significant. Citation: Jackman, C. H., D. R. Marsh, F, NOy, and ozone [e.g., Heath et al., 1977; Thomas et al., 1983; McPeters and Jackman, 1985; Mc

Jackman, Charles H.

41

Long-term stable polymer solar cells with significantly reduced burn-in loss.  

PubMed

The inferior long-term stability of polymer-based solar cells needs to be overcome for their commercialization to be viable. In particular, an abrupt decrease in performance during initial device operation, the so-called 'burn-in' loss, has been a major contributor to the short lifetime of polymer solar cells, fundamentally impeding polymer-based photovoltaic technology. In this study, we demonstrate polymer solar cells with significantly improved lifetime, in which an initial burn-in loss is substantially reduced. By isolating trap-embedded components from pristine photoactive polymers based on the unimodality of molecular weight distributions, we are able to selectively extract a trap-free, high-molecular-weight component. The resulting polymer component exhibits enhanced power conversion efficiency and long-term stability without abrupt initial burn-in degradation. Our discovery suggests a promising possibility for commercial viability of polymer-based photovoltaics towards real solar cell applications. PMID:25483206

Kong, Jaemin; Song, Suhee; Yoo, Minji; Lee, Ga Young; Kwon, Obum; Park, Jin Kuen; Back, Hyungcheol; Kim, Geunjin; Lee, Seoung Ho; Suh, Hongsuk; Lee, Kwanghee

2014-01-01

42

Long-term stable polymer solar cells with significantly reduced burn-in loss  

NASA Astrophysics Data System (ADS)

The inferior long-term stability of polymer-based solar cells needs to be overcome for their commercialization to be viable. In particular, an abrupt decrease in performance during initial device operation, the so-called ‘burn-in’ loss, has been a major contributor to the short lifetime of polymer solar cells, fundamentally impeding polymer-based photovoltaic technology. In this study, we demonstrate polymer solar cells with significantly improved lifetime, in which an initial burn-in loss is substantially reduced. By isolating trap-embedded components from pristine photoactive polymers based on the unimodality of molecular weight distributions, we are able to selectively extract a trap-free, high-molecular-weight component. The resulting polymer component exhibits enhanced power conversion efficiency and long-term stability without abrupt initial burn-in degradation. Our discovery suggests a promising possibility for commercial viability of polymer-based photovoltaics towards real solar cell applications.

Kong, Jaemin; Song, Suhee; Yoo, Minji; Lee, Ga Young; Kwon, Obum; Park, Jin Kuen; Back, Hyungcheol; Kim, Geunjin; Lee, Seoung Ho; Suh, Hongsuk; Lee, Kwanghee

2014-12-01

43

Climate signature of solar irradiance variations: analysis of long-term instrumental, historical, and proxy data  

Microsoft Academic Search

The signature of solar irradiance variations on decadal-to-centennial climate variability is analysed by means of statistical analysis of long-term instrumental, historical, and proxy data sets. Solar variations associated with the Schwabe, Hale, and Gleissberg cycles are detected by their spatial patterns in sea-surface temperature and sea-level pressure. Different statistical methods for instrumental and proxy data show that the mode related

Gerrit Lohmann; Norel Rimbu; Mihai Dima

2004-01-01

44

Improvement on the long-term stability of flexible plastic dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

We investigate the long-term stability of performance for plastic dye-sensitized solar cells (DSSCs) based on organic iodides (TBAI or PMII) in methoxypropionitrile-based electrolytes. Plastic DSSCs containing TBAI maintain 96.9% of baseline efficiency under more than 1000 h prolonged one sun light irradiation and thermal stress (60 °C) aging. The factors of device long-term stability, such as the effects of organic iodides, cell-sealing conditions, and the sheet resistance of indium tin oxide coated polyethylene naphthalate substrate (ITO/PEN) are discussed via using electrochemical impedance spectroscopy and electrical resistance measurement.

Lee, Kun-Mu; Chiu, Wei-Hao; Lu, Ming-De; Hsieh, Wen-Feng

2011-10-01

45

Long-term measurements of solar spectral irradiance variability: toward the establishment of a climate record  

NASA Astrophysics Data System (ADS)

Knowledge of the top of the atmosphere (TOA) solar spectral irradiance (SSI) is crucial in interpreting the spectrally dependent radiative processes throughout Earth's climate system. Where this energy is deposited into the atmosphere and surface, how the climate responds to solar variability, and the mechanisms of climate response, are highly dependent on how the incident solar radiation is distributed with wavelength. In order to advance understanding of how natural and anthropogenic process affect Earth's climate system there is a strong scientific imperative to maintain accurate, long-term records of climate forcing and response. The contin-uation of SSI measurements provides a unique opportunity to characterize poorly understood wavelength dependent climate processes. Coupled chemistry-climate models require realistic assessments of the magnitudes and long-term trends in SSI for the interpretation and quantifi-cation of solar forcing in climate change scenarios. This places stringent requirements on the absolute calibration of the instrument (tied directly to international standards) and the ability to maintain that calibration on-orbit (long-term stability). The Spectral Irradiance Monitor (SIM) is a solar spectral radiometer that continuously monitors the SSI from 200 nm -2400 nm, a wavelength region encompassing 96% of the total solar irradiance. The SIM instrument is included as part of the Total and Spectral Solar Irradiance Sensor (TSIS) to continue the mea-surement of SSI, which began with the SOlar Radiation and Climate Experiment (SORCE), launched in 2003. SORCE SIM measurements have characterized SSI variability during the descending phase of Solar Cycle (SC) 23, but the determination of multi-solar cycle dependen-cies remains a key climatic uncertainty. Analysis of the measured spectral irradiance variability during the SORCE mission has resulted in a number of instrument design refinements central to maintaining, on-orbit, the long-term absolute calibration to the International System of Units (SI) irradiance standards (0.2% absolute) and achieve the necessary measurement precision and long-term reproducibility (0.05 -0.01% relative per year) to meet the needs for establishing a climate record of solar spectral irradiance. We will review the findings from the SORCE SIM observations over the past 7 years, a time period encompassing the declining phase of SC 23 and the start of SC 24, and how these results guided performance enhancements that will be applied to the TSIS SIM instrument to meet the needs for climate monitoring of solar spectral irradiance into the future.

Richard, Erik; Harder, Jerald; Pilewskie, Peter; Fontenla, Juan; Woods, Thomas; Brown, Steven; Lykke, Keith

46

Long-term temperature effects on GaAs solar cells  

NASA Technical Reports Server (NTRS)

The thermal degradation of AlGaAs solar cells resulting from a long-term operation in a space environment is investigated. The solar cell degradation effects caused by zinc and aluminum diffusion as well as deterioration by arsenic evaporation are presented. Also, the results are presented of experimental testing and measurements of various GaAs solar cell properties while the solar cell was operating in the temperature range of 27 C to 350 C. In particular, the properties of light current voltage curves, dark current voltage curves, and spectral response characteristics are given. Finally, some theoretical models for the annealing of radiation damage over various times and temperatures are included.

Heinbockel, J. H.; Hong, K. H.

1979-01-01

47

Hybrid solar\\/wind power system probabilistic modelling for long-term performance assessment  

Microsoft Academic Search

This paper presents a probabilistic approach based on the convolution technique to assess the long-term performance of a hybrid solar–wind power system (HSWPS) for both stand-alone and grid-linked applications. To estimate energy performance of HSWPS the reliability analysis is performed by the use of the energy index of reliability (EIR) directly related to energy expected not supplied (EENS). Analytical expressions

G. Tina; S. Gagliano; S. Raiti

2006-01-01

48

Long-term performance of solar-assisted heat pump water heater  

Microsoft Academic Search

A long-term reliability test of an integral-type solar-assisted heat pump water heater (ISAHP) was carried out. The prototype has been running continuously for more than 13,000 h with total running time >20,000 h during the past 5 yr. The measured energy consumption is 0.019 kWh\\/l of hot water at 57 oC that is much less than the backup electric energy

B. J Huang; C. P Lee

2004-01-01

49

Mitigating the Long term Operating Extreme Load through Active Control  

NASA Astrophysics Data System (ADS)

The parameters influencing the long term extreme operating design loads are identified through the implementation of a Design of Experiment (DOE) method. A function between the identified critical factors and the ultimate out-of-plane loads on the blade is determined. Variations in the initial blade azimuth location are shown to affect the extreme blade load magnitude during operation in normal turbulence wind input. The simultaneously controlled operation of generator torque variation and pitch variation at low blade pitch angles is detected to be responsible for very high loads acting on the blades. Through gain scheduling of the controller (modifications of the proportional Kp and the integral K gains) the extreme loads are mitigated, ensuring minimum instantaneous variations in the power production for operation above rated wind speed. The response of the blade load is examined for different values of the integral gain as resulting in rotor speed error and the rate of change of rotor speed. Based on the results a new load case for the simulation of extreme loads during normal operation is also presented.

Koukoura, Christina; Natarajan, Anand

2014-12-01

50

Long term weathering effects on the thermal performance of the solaron (air) solar collector  

NASA Technical Reports Server (NTRS)

The test procedures and the results obtained during the evaluation test program on the Solaron Corporation air-type solar collector are presented. The tests were performed under simulated conditions, following long-term exposure to natural weathering conditions. The Solaron Model 2001, air-type solar collector has a gross area of 19 square feet and the weight is 160 pounds. The absorber plate is made of 24-gage steel, the coating is baked-on black paint, the cover consists of two sheets of 1/8-inch low-iron tempered glass, and the insulation is one thickness of 3 5/8-inch fiberglass batting.

1979-01-01

51

Variations in the solar fluxes of helium and protons on the long-term scale  

NASA Astrophysics Data System (ADS)

A reconstruction of data on ancient (to ˜600 Ma ago) solar fluxes of protons and helium has been performed on the basis of isotopic investigations of helium and neon in lunar soil samples from columns delivered by the automatic stations Luna-16 and Luna-24 in 1970 and 1976. Recent investigations have shown the presence of long-term climate variations, which can be explained in the context of solar-terrestrial links. However, the "space" impact, simultaneously with the Sun's influence on the Earth, takes place in the form of cosmic ray irradiation and as an influence on the Earth that is exerted by the flux of cosmic dust and meteorites (including the very large ones at the early stage of the Earth evolution). Therefore the existence of long-term variability of solar corpuscular fluxes may serve as direct evidence of the manifestation of solar-terrestrial links. The possibility of finding these links appears on the basis of the revealed variations of solar wind fluxes with an age from the contemporary level to the level of ˜600 Ma ago.

Anufriev, G. S.

2014-11-01

52

Progress Towards Deriving an Improved Long-Term Global Solar Resource  

NASA Technical Reports Server (NTRS)

This paper describes an ongoing project to provide the National Renewable Energy Laboratory (NREL) with a global long-term advanced global solar mapping production system for improved depiction of historical solar resources and to provide a mechanism for continual updates. This new production system is made possible by the efforts of NASA and NOAA to completely reprocess the International Satellite Cloud Climatology Project (ISCCP) data set that provides satellite visible and infrared radiances together with retrieved cloud and surface properties on a 10 km, 3-hourly basis beginning July 1983. We provide a general overview of this project, samples of the new solar irradiance mapped data products, and comparisons to surface measurements. Samples of the use of the SUNY-Albany solar irradiance algorithm applied to the ISCCP data show very good agreement with high quality surface measurements. We identify the next steps in the production of the data set.

Cox, Stephen J.; Mikovitz, J. Colleen; Zhang, Taiping; Sorlie, Susan; Stackhouse, Paul W., Jr.; Perez, Richard; Hemker, Karl, Jr.; Schlemmer, James; Kivalov, Sergey; Renne, David; Sengupta, Manajit; Bates, John; Knapp, Kenneth

2013-01-01

53

Long-term variation in the upper atmosphere as seen in the geomagnetic solar quiet daily variation  

NASA Astrophysics Data System (ADS)

Characteristics of long-term variation in the amplitude of solar quiet (Sq) geomagnetic field daily variation have been investigated using 1-h geomagnetic field data obtained from 69 geomagnetic observation stations within the period of 1947 to 2013. The Sq amplitude observed at these geomagnetic stations showed a clear dependence on the 10- to 12-year solar activity cycle and tended to be enhanced during each solar maximum phase. The Sq amplitude was the smallest around the minimum of solar cycle 23/24 in 2008 to 2009. The relationship between the solar F10.7 index and Sq amplitude was approximately linear but about 53% of geomagnetic stations showed a weak nonlinear relation to the solar F10.7 index. In order to remove the effect of solar activity seen in the long-term variation of the Sq amplitude, we calculated a linear or second-order fitting curve between the solar F10.7 index and Sq amplitude during 1947 to 2013 and examined the residual Sq amplitude, which is defined as the deviation from the fitting curve. As a result, the majority of trends in the residual Sq amplitude that passed through a trend test showed negative values over a wide region. This tendency was relatively strong in Europe, India, the eastern part of Canada, and New Zealand. The relationship between the magnetic field intensity at 100-km altitude and residual Sq amplitude showed an anti-correlation for about 71% of the geomagnetic stations. Furthermore, the residual Sq amplitude at the equatorial station (Addis Ababa) was anti-correlated with the absolute value of the magnetic field inclination. This implies movement of the equatorial electrojet due to the secular variation of the ambient magnetic field.

Shinbori, Atsuki; Koyama, Yukinobu; Nose, Masahito; Hori, Tomoaki; Otsuka, Yuichi; Yatagai, Akiyo

2014-12-01

54

Long-term variation in the upper atmosphere as seen in the geomagnetic solar quiet (Sq) daily variation  

NASA Astrophysics Data System (ADS)

It has been well-known that geomagnetic solar quiet (Sq) daily variation is produced by the global ionospheric currents flowing in the E-region, which are generated by dynamo process via interaction between the neutral wind and ionospheric plasma in a region of the lower thermosphere and ionosphere. Then, to investigate the Sq amplitude is essential for understanding the long-term variations in the ionospheric conductivity and neutral wind of the lower thermosphere and ionosphere. Recently, Elias et al. [2010] reported that the Sq amplitude tends to increase by 5.4-9.9 % in the middle latitudes in a period of 1961-2001. They mentioned that the long-term variation of ionospheric conductivity associated with geomagnetic secular variation mainly determines the Sq trend, but that the rest component is due to ionospheric conductivity enhancement associated with cooling effect in the thermosphere due to increasing greenhouse gas. In the present study, we clarify the characteristics of the long-term variation in the Sq amplitude using the long-term observation data of geomagnetic field and neutral wind. In the present analysis, we used the F10.7 solar flux as a good indicator of the variation in the solar irradiance in the EUV and UV range as well as geomagnetic field data with time resolution of 1 hour observed at 184 geomagnetic stations. The definition of the Sq amplitude is the difference of the H-component between the maximum and minimum every day when the Kp index is less than 4. As a result, the long-term variation in the Sq amplitude at all the geomagnetic stations shows a strong correlation with the solar F10.7 flux which depends on 11-year solar activity. The relationship between the Sq amplitude and F10.7 flux was not linear but nonlinear. This nonlinearity could be interpreted as the decrease of production rate of electrons and ions in the ionosphere for the strong EUV and UV fluxes as already reported by Balan et al. [1993]. In order to minimize the solar activity dependence on the Sq amplitude, we calculated second orders of fitting curve between the F10.7 flux and Sq amplitude during 1950-2011, and examined the residual Sq amplitude defined as the deviation from the fitting curve. The residual Sq amplitude clearly shows increase and decrease trends with the periods of 20 years. Then, it seems that the trends in the residual Sq and Sqp fields are related to the long-term variation in the ionospheric conductivities associated with the secular variation of the ambient magnetic field and the upper atmosphere (for example, plasma and neutral densities). In order to verify qualitatively the above signatures, we need to investigate the long-term variation in the ionospheric conductivities using a calculation tool developed by the IUGONET project.

Shinbori, A.; Koyama, Y.; Yatagai, A. I.; Nose, M.; Hori, T.; Otsuka, Y.

2012-12-01

55

Long-term stabilization of organic solar cells using hindered phenols as additives.  

PubMed

We report on the improvement of long-term stability of organic solar cells (OPV) using hindered phenol based antioxidants as stabilizing additives. A set of seven commercially available hindered phenols are investigated for use in bulk-heterojunction OPV. Polymer:fullerene films based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) are characterized with respect to the initial power conversion efficiency and the long-term stability improvement under illumination in ambient conditions. FTIR spectroscopy is used to trace chemical degradation over time. OPV performance is recorded under ISOS-3 conditions, and an improved long-term performance of OPV devices, manifested in increased accumulated power generation (APG), is found for octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate. Using this additive, APG is increased by a factor of 3 compared to the reference. Observed differences in the stabilization of tested additives are discussed in terms of energetic trap states formation within the HOMO/LUMO gap of the photoactive material, morphological changes, and chemical structure. PMID:25279719

Turkovic, Vida; Engmann, Sebastian; Tsierkezos, Nikos; Hoppe, Harald; Ritter, Uwe; Gobsch, Gerhard

2014-11-12

56

Wnt Pathway Activation in Long Term Remnant Rat Model  

PubMed Central

Progression of chronic kidney disease (CKD) is characterized by deposition of extracellular matrix. This is an irreversible process that leads to tubulointerstitial fibrosis and finally loss of kidney function. Wnt/?-catenin pathway was reported to be aberrantly activated in the progressive damage associated with chronic organ failure. Extensive renal ablation is an experimental model widely used to gain insight into the mechanisms responsible for the development of CKD, but it was not evaluated for Wnt/?-catenin pathway. This study aimed to elucidate if the rat 5/6 renal mass reduction model (RMR) is a good model for the Wnt/?-catenin activation and possible next modulation. RMR model was evaluated at 12 and 18 weeks after the surgery, when CKD is close to end-stage kidney disease demonstrated by molecular and histological studies. Wnt pathway components were analyzed at mRNA and protein level. Our results demonstrate that Wnt pathway is active by increase of ?-catenin at mRNA level and nuclear translocation in tubular epithelium as well as some target genes. These results validate the RMR model for future modulation of Wnt pathway, starting at shorter time after the surgery. PMID:24995284

Banon-Maneus, E.; Rovira, J.; Ramirez-Bajo, M. J.; Moya-Rull, D.; Hierro-Garcia, N.; Takenaka, S.; Diekmann, F.; Eickelberg, O.; Königshoff, M.; Campistol, J. M.

2014-01-01

57

Long term behavior of trapped relativistic electrons and their correlation with solar wind speed  

SciTech Connect

We examine Los Alamos energetic electron data from 1979 through the present to show long term trends in the trapped relativistic electron populations at geosynchronous Earth orbit. Such populations are thought to be associated with high-speed solar wind structures typically present near solar minimum. We will show that high-energy electron fluxes, E > 1.4 MeV, displayed a solar-like cycle of about 10.5 years, but that the behavior is out of phase with the sunspot cycle. We will also compare relativistic electrons during the cycle with solar wind speed from the MIT plasma analyzers on IMP-8. It will be shown that relativistic electrons correlate well with high solar winds only during limited, short periods of time. We will also confirm the observation that the higher-energy electrons occur with a longer delay after the establishment of the high-speed solar wind. Comparison of our data with previously published data indicate that the higher the solar wind speed, the sooner the relativistic electrons occur.

Belian, R.D.; Cayton, T.E.; Christensen, R.A.; Ingraham, J.C.; Reeves, G.D.

1995-12-31

58

Long-Term International Space Station (ISS) Risk Reduction Activities  

NASA Technical Reports Server (NTRS)

As the assembly of the ISS nears completion, it is worthwhile to step back and review some of the actions pursued by the Program in recent years to reduce risk and enhance the safety and health of ISS crewmembers, visitors, and space flight participants. While the initial ISS requirements and design were intended to provide the best practicable levels of safety, it is always possible to further reduce risk given the determination, commitment, and resources to do so. The following is a summary of some of the steps taken by the ISS Program Manager, by our International Partners, by hardware and software designers, by operational specialists, and by safety personnel to continuously enhance the safety of the ISS, and to reduce risk to all crewmembers. While years of work went into the development of ISS requirements, there are many things associated with risk reduction in a Program like the ISS that can only be learned through actual operational experience. These risk reduction activities can be divided into roughly three categories: Areas that were initially noncompliant which have subsequently been brought into compliance or near compliance (i.e., Micrometeoroid and Orbital Debris [MMOD] protection, acoustics) Areas where initial design requirements were eventually considered inadequate and were subsequently augmented (i.e., Toxicity hazard level-4 materials, emergency procedures, emergency equipment, control of drag-throughs) Areas where risks were initially underestimated, and have subsequently been addressed through additional mitigation (i.e., Extravehicular Activity [EVA] sharp edges, plasma shock hazards). Due to the hard work and cooperation of many parties working together across the span of more than a decade, the ISS is now a safer and healthier environment for our crew, in many cases exceeding the risk reduction targets inherent in the intent of the original design. It will provide a safe and stable platform for utilization and discovery for years to come.

Forroci, Michael P.; Gafka, George K.; Lutomski, Michael G.; Maher, Jacilyn S.

2011-01-01

59

Solar Drivers of 11-yr and Long-Term Cosmic Ray Modulation  

NASA Astrophysics Data System (ADS)

In the current paradigm for the modulation of galactic cosmic rays (GCRs), diffusion is taken to be the dominant process during solar maxima while drift dominates at minima. Observations during the recent solar minimum challenge the pre-eminence of drift at such times. In 2009, the ˜2 GV GCR intensity measured by the Newark neutron monitor increased by ˜5% relative to its maximum value two cycles earlier even though the average tilt angle in 2009 was slightly larger than that in 1986 (˜20° vs. ˜14°), while solar wind B was significantly lower (˜3.9 nT vs. ˜5.4 nT). A decomposition of the solar wind into high-speed streams, slow solar wind, and coronal mass ejections (CMEs; including post-shock flows) reveals that the Sun transmits its message of changing magnetic field (diffusion coefficient) to the heliosphere primarily through CMEs at solar maximum and high-speed streams at solar minimum. Long-term reconstructions of solar wind B are in general agreement for the ˜1900-present interval and can be used to reliably estimate GCR intensity over this period. For earlier epochs, however, a recent 10Be-based reconstruction covering the past ˜104 years shows nine abrupt and relatively short-lived drops of B to ?0 nT, with the first of these corresponding to the Spörer minimum. Such dips are at variance with the recent suggestion that B has a minimum or floor value of ˜2.8 nT. A floor in solar wind B implies a ceiling in the GCR intensity (a permanent modulation of the local interstellar spectrum) at a given energy/rigidity. The 30-40% increase in the intensity of 2.5 GV electrons observed by Ulysses during the recent solar minimum raises an interesting paradox that will need to be resolved.

Cliver, E. W.; Richardson, I. G.; Ling, A. G.

2013-06-01

60

Solar Drivers of 11-yr and Long-Term Cosmic Ray Modulation  

NASA Technical Reports Server (NTRS)

In the current paradigm for the modulation of galactic cosmic rays (GCRs), diffusion is taken to be the dominant process during solar maxima while drift dominates at minima. Observations during the recent solar minimum challenge the pre-eminence of drift: at such times. In 2009, the approx.2 GV GCR intensity measured by the Newark neutron monitor increased by approx.5% relative to its maximum value two cycles earlier even though the average tilt angle in 2009 was slightly larger than that in 1986 (approx.20deg vs. approx.14deg), while solar wind B was significantly lower (approx.3.9 nT vs. approx.5.4 nT). A decomposition of the solar wind into high-speed streams, slow solar wind, and coronal mass ejections (CMEs; including postshock flows) reveals that the Sun transmits its message of changing magnetic field (diffusion coefficient) to the heliosphere primarily through CMEs at solar maximum and high-speed streams at solar minimum. Long-term reconstructions of solar wind B are in general agreement for the approx. 1900-present interval and can be used to reliably estimate GCR intensity over this period. For earlier epochs, however, a recent Be-10-based reconstruction covering the past approx. 10(exp 4) years shows nine abrupt and relatively short-lived drops of B to < or approx.= 0 nT, with the first of these corresponding to the Sporer minimum. Such dips are at variance with the recent suggestion that B has a minimum or floor value of approx.2.8 nT. A floor in solar wind B implies a ceiling in the GCR intensity (a permanent modulation of the local interstellar spectrum) at a given energy/rigidity. The 30-40% increase in the intensity of 2.5 GV electrons observed by Ulysses during the recent solar minimum raises an interesting paradox that will need to be resolved.

Cliver, E. W.; Richardson, I. G.; Ling, A. G.

2011-01-01

61

Accelerometer's position independent physical activity recognition system for long-term activity monitoring in the elderly  

Microsoft Academic Search

Mobility is a good indicator of health status and thus objective mobility data could be used to assess the health status of\\u000a elderly patients. Accelerometry has emerged as an effective means for long-term physical activity monitoring in the elderly.\\u000a However, the output of an accelerometer varies at different positions on a subject’s body, even for the same activity, resulting\\u000a in

Adil Mehmood Khan; Young-Koo Lee; Sungyoung Lee; Tae-Seong Kim

2010-01-01

62

Long-term variation in the upper atmosphere as seen in the amplitude of the geomagnetic solar quiet daily variation  

NASA Astrophysics Data System (ADS)

It has been well-known that geomagnetic solar quiet (Sq) daily variation is produced by global ionospheric currents flowing in the E-region from middle latitudes to the magnetic equator. These currents are generated by a dynamo process via interaction between the neutral wind and ionospheric plasma in a region of the thermosphere and ionosphere. From the Ohm's equation, the ionospheric currents strongly depend on the ionospheric conductivity, polarization electric field and neutral wind. Then, to investigate the Sq amplitude is essential for understanding the long-term variations in the ionospheric conductivity and neutral wind of the thermosphere and ionosphere. Elias et al. [2010] found that the Sq amplitude tends to increase by 5.4-9.9 % in the middle latitudes from 1961 to 2001. They mentioned that the long-term variation of ionospheric conductivity associated with geomagnetic secular variation mainly determines the Sq trend, but that the rest component is ionospheric conductivity enhancement associated with cooling effects in the thermosphere due to increasing the greenhouse gases. In this talk, we clarify the characteristics of the long-term variation in the Sq amplitude using the long-term observation data of geomagnetic field and neutral wind. These observation data have been provided by the IUGONET (Inter-university Upper atmosphere Global Observation NETwork) project. In the present analysis, we used the F10.7 flux as an indicator of the variation in the solar irradiance in the EUV and UV range, geomagnetic field data with time resolution of 1 hour. The definition of the Sq amplitude is the difference of the H-component between the maximum and minimum per day when the Kp index is less than 4. As a result, the Sq amplitude at all the stations strongly depends on 11-year solar activity, and tends to enhance more during the high activities (19- and 22- solar cycles) than during the low activity (20-solar cycle). The Fourier spectra of the F10.7 flux and Sq amplitude at Guam (13.59N, 144.87E) showed that the common peaks appear at the periods of 5.5, 7,5 and 10.5 years with the coherence of more than 0.9 while the spectrum peaks around 0.5 and 1.0 year appear only in the Sq amplitude. The former peak of the Sq amplitude is due to the solar activity while the latter is a cause of the upper atmosphere variation. In order to minimize the solar activity dependence of the Sq amplitude, we calculated the residual Sq amplitude using a second degree polynomial curve between the F10.7 and Sq amplitude during 1957-2010, and examined the residual Sq field defined as the deviation from the fitting curve. The residual Sq amplitude showed a clear tendency to increase and decrease during the periods of 1957-1992 and 1993-2010, respectively. It should be noted that the residual Sq amplitude around 2010 is almost the same level as that around 1970. In order to verify qualitatively the above signatures, we need to investigate the long-term variation in the ionospheric conductivities calculated with the IRI-2007 and MSIS-00 models.

Shinbori, A.; Koyama, Y.; Hayashi, H.; Nose, M.; Hori, T.; Otsuka, Y.; Tsuda, T.

2011-12-01

63

Long term weathering effects on the thermal performance of the sunworks (liquid) solar collector  

NASA Technical Reports Server (NTRS)

The test procedures used and the results obtained during the evaluation test program of the Sunworks single-covered liquid solar collector are presented. The tests were performed under simulated conditions, following long-term exposure to natural weathering conditions. The sunworks collector is a flat-plate solar collector. The absorber plate is copper with copper tubes bonded by soft solder, and is coated with Enthon selective black with an absorptivity factor of .87 similar to .92 and an emissivity factor of .10 similar to .20. It has a single glass cover of 3/16 inches tempered glass and weighs about 115 pounds. The overall dimensions of the collector are 36 x 84 x 4 inches.

1979-01-01

64

Developing Long-Term Physical Activity Participation: A Grounded Theory Study with African American Women  

ERIC Educational Resources Information Center

Regular physical activity is linked to a reduced risk of obesity and chronic disease. African American women bear a disproportionate burden from these conditions and many do not get the recommended amount of physical activity. Long-term success of interventions to initiate and maintain a physically active lifestyle among African American women has…

Harley, Amy E.; Buckworth, Janet; Katz, Mira L.; Willis, Sharla K.; Odoms-Young, Angela; Heaney, Catherine A.

2009-01-01

65

Effect of Long-Term Physical Activity Practice after Cardiac Rehabilitation on Some Risk Factors  

ERIC Educational Resources Information Center

The objective of this study was to evaluate the effects of long-term physical activity practice after a cardiac rehabilitation program on weight, physical capacity and arterial compliance. The Dijon Physical Activity Score was used to identify two groups: sedentary and active. Weight, distance at the 6-min walk test and the small artery elasticity…

Freyssin, Celine, Jr.; Blanc, Philippe; Verkindt, Chantal; Maunier, Sebastien; Prieur, Fabrice

2011-01-01

66

Long-term calibration monitoring of medium resolution spectral imager (MERSI) solar bands onboard FY-3  

NASA Astrophysics Data System (ADS)

Medium Resolution Spectral Imager (MERSI) is a keystone instrument onboard Fengyun-3 (FY-3), the second generation of polar-orbiting meteorological satellites in China. This paper summarizes the knowledge of MERSI instrument in terms of sensor design, calibration algorithm, and long term calibration monitoring. The calibration monitoring of its reflective solar bands (RSBs) is conducted using China Radiometric Calibration Sites (CRCS) vicarious calibration (VC), global multi-site calibration tracking, visible onboard calibrator (VOC) monitoring and deep convective cloud (DCC) monitoring. All these methods provide results with good consistency . It is found that there is significant degradation over 10% in the shorter RSB bands (<500 nm), with the largest in band 8 (412 nm) of approximately 35% during the past four years. The performance in the red and near-infrared (600 to 900 nm) is relatively stable. The overall uncertainty of the MERSI top-of-the-atmosphere (TOA) reflectance is less than 5% verified through several methods.

Sun, Ling; Hu, Xiuqing; Chen, Lin

2012-11-01

67

The mid-term and long-term solar quasi-periodic cycles and the possible relationship with planetary motions  

NASA Astrophysics Data System (ADS)

This work investigates the solar quasi-periodic cycles with multi-timescales and the possible relationships with planetary motions. The solar cycles are derived from long-term observations of the relative sunspot number and microwave emission at frequency of 2.80 GHz. A series of solar quasi-periodic cycles with multi-timescales are registered. These cycles can be classified into three classes: (1) the strong PLC (PLC is defined as the solar cycle with a period very close to the ones of some planetary motions, named as planetary-like cycle) which is related strongly with planetary motions, including nine periodic modes with relatively short period ( P<12 yr), and related to the motions of the inner planets and of Jupiter; (2) the weak PLC, which is related weakly to planetary motions, including two periodic modes with relatively long period ( P>12 yr), and possibly related to the motions of outer planets; (3) the non-PLC, for which so far there has been found no clear evidence to show the relationship with any planetary motions. Among the planets, Jupiter plays a key role in most periodic modes due to its sidereal motion or spring tidal motions associated with other planets. Among planetary motions, the spring tidal motion of the inner planets and of Jupiter dominates the formation of most PLCs. The relationships between multi-timescale solar periodic modes and the planetary motions will help us to understand the essential nature and prediction of solar activities.

Tan, Baolin; Cheng, Zhuo

2013-02-01

68

Long-Term Dynamics of Small Bodies in the Solar System  

NASA Technical Reports Server (NTRS)

As part of the NASA Planetary Geology and Geophysics program Prof. Norm Murray (CITA) and I have been conducting investigations of the long-term dynamics of small bodies in the outer solar system. This grant, and its predecessor NAG5-7761, supported travel for collaboration by the Investigators and also supports Murray during an annual one month visit to the CfA for further collaboration. In the course of this grant we made a number of advances in solar system dynamics. For example, we developed an analytic model for the origin and consequence of chaos associated with three-body resonances in the asteroid belt. This has been shown to be important for the delivery of near Earth objects. We later extended this model to three-body resonances among planets. We were able to show that the numerically identified chaos among the outer planets results from a three-body resonance involving Jupiter, Saturn, and Uranus. The resulting paper was awarded the 1999 Newcomb Cleveland award from the AAAS. This award singles out one paper published in Science each year for distinction. This grant has also supported, in part, my participate in other solar system dynamics projects. The results from those collaborations are also listed.

Saunders, Steve (Technical Monitor); Holman, Matthew J.

2005-01-01

69

2006 Nature Publishing Group Long-term eruptive activity at a submarine arc  

E-print Network

© 2006 Nature Publishing Group Long-term eruptive activity at a submarine arc volcano Robert W , Douglas A. Wiens12 & Yoshihiko Tamura13 Three-quarters of the Earth's volcanic activity is submarine of submarine eruptions have been indirect, made from surface vessels or made after the fact1­6 . We describe

Chadwick, Bill

70

Long-term evolution in the global distribution of solar wind speed and density fluctuations during 1997-2009  

NASA Astrophysics Data System (ADS)

Interplanetary scintillation (IPS) observations made with the 327-MHz multistation system of the Solar-Terrestrial Environment Laboratory (STEL) are analyzed to investigate the global distribution of solar wind speed and density fluctuations (?Ne) and their evolution during 1997-2009. This study aims at elucidating the evolution of ?Ne distribution during the cycle 23 and subsequent extended minimum, which is useful for improving understanding of the heliospheric response to the peculiar solar activity. The computer-assisted tomography (CAT) method is used in the present study to deconvolve the line-of-sight integration of STEL IPS observations. This CAT method enables retrieval of the quasi-stationary large-scale structure of the background solar wind. The results show that the high (low)-latitude region is dominated by reduced (enhanced) ?Ne plasma, being closely associated with the fast (slow) solar wind. The solar wind speed data show a distinct change with solar activity, and an excellent positive (negative) correlation is revealed between the fast (slow) wind area and the polar field strength of the Sun. In contrast, the ?Ne data do not show such a solar cycle variation, but instead reveal a significant increase in the fractional area of low-?Ne region in 2004 preceded by a constant value with a small amount of fluctuation. This change is observed for all latitudes, distinctly after 2007 for low latitudes. Our finding is consistent with the long-term variation of the solar wind density revealed from in situ measurements at the Earth orbit, if ?Ne ? Ne (where Ne is the solar wind electron density), and also consistent with the coronal hole distribution during the last solar cycle. It is found that ?Ne is inversely correlated with the solar wind speed V. We obtain the best fit power law function ?Ne ? V-0.36±0.14 for V > 350 km/s, which is basically consistent with our earlier result. This fact suggests that the fractional density fluctuations ?Ne/Ne are greater in the fast wind than in the slow wind. There is no systematic variation in the power law index or slope during 1997-2009 except for a null slope in 2000, which may be ascribed to an insufficient resolution of the CAT analysis. Thus, the inverse relation between ?Ne and V is regarded as a general rule for solar wind turbulence. The important point to note is that a marked drop in ?Ne occurs for the slow speed wind, V < 350 km/s, particularly for 2004 and 2009. This fact may be attributed to different source conditions of the very-low-speed solar wind.

Tokumaru, Munetoshi; Kojima, Masayoshi; Fujiki, Ken'ichi

2012-06-01

71

Long-Term Dynamics of Small Bodies in the Solar System  

NASA Technical Reports Server (NTRS)

As part of the NASA Planetary Geology and Geophysics program Prof. Norm Murray (CITA) and I have been conducting investigations of the long-term dynamics of small bodies in the outer solar system. This grant, and its predecessor NAG5- 7761, supports travel for collaboration by the Investigators and also supports Murray during an annual one month visit to the CfA for further collaboration. In the course of this grant we made a number of advances in solar system dynamics. For example, we developed an analytic model for the origin and consequence of chaos associated with three-body resonances in the asteroid belt. This has been shown to be important for the delivery of near Earth objects. We later extended this model to three- body resonances among planets. We were able to show that the numerically identified chaos among the outer planets results from a three-body resonance involving Jupiter, Saturn, and Uranus. The resulting paper was awarded the 1999 Newcomb Cleveland award from the AAAS. This award singles out one paper published in Science each year for distinction.

Holman, Matthew J.

2004-01-01

72

NASA's Long-term Debris Environment and Active Debris Removal Modeling Activities  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the modeling activities for modeling of the long-term debris environment, the updated assessments of the environment, and the necessity to model the effectiveness of the technologies aimed at the removal of orbital debris. The model being used is named a LEO to GEO environment debris (LEGEND). It is a high fidelity three dimensional numerical simulation model with the capability to treat objects individually. It uses a Monte Carlo approach and a collision probability evaluation algorithm to simulate future satellite breakups and the growth of the debris populations.

Liou, J.-C.

2009-01-01

73

Amygdala Activity at Encoding Correlated with Long-Term, Free Recall of Emotional Information  

Microsoft Academic Search

Positron emission tomography of cerebral glucose metabolism in adult human subjects was used to investigate amygdaloid complex (AC) activity associated with the storage of long-term memory for emotionally arousing events. Subjects viewed two videos (one in each of two separate positron emission tomography sessions, separated by 3-7 days) consisting either of 12 emotionally arousing film clips (``E'' film session) or

Larry Cahill; Richard J. Haier; James Fallon; Michael T. Alkire; Cheuk Tang; David Keator; Joseph Wu; James L. McGaugh

1996-01-01

74

Long-Term Modeling of Solar Energy: Analysis of Concentrating Solar Power (CSP) and PV Technologies  

SciTech Connect

This report presents an overview of research conducted on solar energy technologies and their implementation in the ObjECTS framework. The topics covered include financing assumptions and selected issues related to the integration of concentrating thermal solar power (CSP) and photovoltaics PV technologies into the electric grid. A review of methodologies for calculating the levelized energy cost of capital-intensive technologies is presented, along with sensitivity tests illustrating how the cost of a solar plant would vary depending on financing assumptions. An analysis of the integration of a hybrid concentrating thermal solar power (CSP) system into the electric system is conducted. Finally a failure statistics analysis for PV plants illustrates the central role of solar irradiance uncertainty in determining PV grid integration characteristics.

Zhang, Yabei; Smith, Steven J.

2007-08-16

75

Long term non-thermal emission of solar flares and the Neupert effect  

NASA Astrophysics Data System (ADS)

Observations of hard (Anti-Coincidence System of Spectrometer on INTEGRAL (ACS SPI), ˜150 keV) and soft (GOES 1-8 A) X-ray emission as well as microwave emission (15.5 GHz) during the solar flare of 2005 September 7 and 2006 December 6 and 13 are analyzed. Timeprofiles of non-thermal emission of these flares provide evidence of complex behavior of the solar chromosphere and corona during more than one hour after flare onsets, including several acts of energy release and particle acceleration. In a case the first two flares the Neupert effect is observed for the most intensive peak of the non-thermal emission, but not during the soft X-ray decay phase, when the hard X-ray and microwave emission is still well above background. At that time the hard X-ray intensity is considerably less in comparison with the main peak, but the microwave intensity doesn't change significantly. Observations of the long-term hard X-ray emission during the 2006 December 13 event were complicated due to fast arrival of relativistic solar protons, but the Neupert effect was not observed even for the main peak. For the comparable intensities of the microwave emission on December 6 and 13, the maximum hard X-ray intensity on December 13 was depressed by about one order. These facts point out on emission from low density medium and small precipitation to more dense layers during the time, when the Neupert effect is not valid, i.e. emission from the coronal trap.

Struminsky, Alexei

76

Stellar activity cycles from long-term data by robotic telescopes  

NASA Astrophysics Data System (ADS)

All results about stellar activity cycles stem from decades-long systematic observations that were done by small telescopes. Without these equipments we would not know much, if anything, about stellar activity cycles, like those we see and observe easily on the nearest star, the Sun. In the early 80's of the last century systematic photometric monitoring of active stars began with automated photometric telescopes (APTs), some of which continue the observations to date. The Vienna-Potsdam APT now works for about two decades (Strassmeier et al. 1997), similarly to the 4-College Consortium APT (Dukes et al. 1995), while the Catania APT (Rodono et al. 2001) was closed down a few years ago. These small tools with the same setups for decades do not cost much and are relatively cheap to maintain. The longest continuous photometric datasets of a few objects from APTs span now over 30 years, which, together with earlier, manually-obtained data allow to study those activity cycles of stars which are in the order of 10 years or shorter: to be sure in the timescale of a cycle it should be observed repeatedly at least 2-3 times. The spectroscopic automated telescope STELLA (Strassmeier et al. 2004), built in the first decade of this century, measured already a few dozens of radial velocity curves for long-period binary stars and measured their activity levels (Strassmeier et al. 2012); these results can be gathered only by robotic telescopes. Only with STELLA it is possible to study the decades-long behavior of starspots on active giants with long rotational periods via Doppler Imaging. As the databases were growing it became clear that stars, just as the Sun, had multiple cycles. It was also found that stellar cycles showed systematic changes and that the cycle lengths correlated with the rotational periods of the stars. Extensive summaries of stellar activity cycles are found in Baliunas et al. (1995) using the Mt. Wilson Ca-index survey, and Oláh et al. (2009) based on automated photometry+manual data from the literature, resulting in the detection of positive correlation between the rotational rates and cycle length(s) in the sense that faster rotating stars have shorter cycle(s). The long-term, B-V and U-B color index changes of active stars were thoroughly studied by Messina (2008). Direct connection between the magnetic behavior and the orbit of a system containing an active star is seldom observed; such examples are presented by Strassmeier et al. (2011) and Oláh et al. (2013). Based on the data from the DASCH (Digital Access to a Sky Century at Harvard) project, three active K-giants' long-term variability on the timescale of decades to 100 years have beed discovered by Tang et al. (2010). The ASAS database was used to study the cyclic behavior of field M-dwarf stars by Savanov (2012) who found no correlation between the rotation rates and cycle lengths of these objects, suggesting a different type of dynamo to those that drive the dynamo in the RS CVn systems and related active stars, e.g., in Oláh et al. (2009). Recently, Vida & Oláh (2013) determined cycles on the timescale of a year on fast rotating, late-type dwarf stars measured by the Kepler space telescope. However, despite the extremely high precision and time cadence, the Kepler data do not allow to study very long- term phenomena, such as the activity cycles of solar-like stars, due to the limited lifetime of the mission. One of the most important factors in studying stellar activity cycles is time, which cannot be overtaken by any means. It needs systematic, uninterrupted observations for dozens of years, preferably with the same instrument, to avoid systematic effects in the observed long-term variations. Another point is that most of the known magnetically active stars are quite bright objects needing a small telescope to be observed. The construction of automated photometric and spectroscopic telescopes is one of the major, and at the same time low-cost, investments in astronomy. These telescopes and their equipments should be preserved and used as lon

Oláh, K.

2014-03-01

77

Observing Campaign to Monitor Magnetically-Active Dwarfs for Long-Term Variability  

NASA Astrophysics Data System (ADS)

Dr. Styliani (Stella) Kafka of the Department of Terrestrial Magnetism, Carnegie Institute of Washington, requests AAVSO observers to perform long-term photometric monitoring on a number of magnetically active dwarf stars, with an observing frequency of one observation every three days taken with one or more filters. When multiple filters are available, the preferred observations are (in order of precedence): Rc, V, Ic, and B. Please observe such that you obtain a signal to noise of at least 50 (100 or higher is preferred). These objects are all nearby dwarfs known or suspected to have magnetic activity, primarily of the UV Ceti (flare star) or BY Draconis subtypes. Long-term photometric monitoring of these objects will be used in conjunction with other multiwavelength observations from ground-based facilities including the Magellan 6.5-meter and DuPont 2.5-meter telescopes in Chile to understand the long-term magnetic activity cycles of these stars. Such a study can reveal information about the physical natures of these stars, but also about their near space environments and habitability for life. These objects are red, and the variability amplitudes are low, often well below 0.1 magnitudes. The long-term variability due to stellar activity cycles may be much lower. Photometric accuracy rather than the number of observations are key to the success of this project. Unaccounted-for atmospheric effects such as extinction will likely overwhelm any long-term signal from these stars. Observers are strongly urged to fully calibrate their systems and to carefully reduce and transform their photometry to standard photometric passbands, including corrections for airmass/atmospheric extinction. Parameters for 40 objects are given. Observations should be submitted to the AAVSO International Database.

Templeton, Matthew R.

2009-10-01

78

Analysis of Ca II K images aiming to determine long-term trends in solar irradiance variability  

NASA Astrophysics Data System (ADS)

The change in radiative output of the Sun on time scales longer than a day is attributed to the variability in solar surface magnetic fields. Direct irradiance measurements are only available for less than four decades. To reconstruct long term trends in solar total and spectral irradiance, proxies of solar surface magnetism like sunspot, facular and network areas are needed. Currently, sunspot records alone are used for this purpose, from which the deduction of facular and network areas is rather indirect. Historical records of full disk images of the Sun taken in the Ca II K spectral line (393.3 nm) have the potential to provide far more direct information about the distribution and evolution of faculae and network elements. The latter appear as bright regions in the Ca II K spectroheliograms and their intensity is correlated with the magnetic field strength of the features on the solar surface. Solar full disk images in the Ca II K line have been recorded since the beginning of the 20th century at a number of solar observatories such as at Arcetri (Italy), Mount Wilson(California, US) and Kodaikanal (India). The images are available in digitized archives that contain the data processed for standard instrumental calibrations. To utilize these records for irradiance studies, the next step is to identify the bright magnetic features from the images using feature recognition techniques. We test different feature identification methods which are first applied to a set of recent images from the PSPT instrument at the Osservatorio Astronomico di Roma, taken during three periods characterized by high, medium and low levels of activity. Then the performance of these methods to historical images from Arcetri, Mt. Wilson and Kodaikanal archives is tested. The results will be presented and discussed here.

Kar, Anuradha; Ermolli, Ilaria; Krivova, Natalie; Solanki, Sami

2013-04-01

79

Non-linear analysis of the long-term behaviour of solar filaments  

NASA Astrophysics Data System (ADS)

The correlation dimension and K2 entropy of solar filaments are investigated using the Carte Synoptique catalogue of solar filaments from 1919 March to 1989 December. It is found that the correlation dimension of full-disc, low-latitude (<50°) and high-latitude (?50°) filament numbers is about 4.05 ± 0.35, 4.1 ± 0.45 and 4.0 ± 0.4, respectively and shows very similar fractal properties when compared with values derived from Wolf sunspot numbers. All K2 entropies of full-disc, low-latitude and high-latitude filament numbers are positive, though larger than the K2 entropy of Wolf sunspot numbers. On the basis of the correlation dimension, positive K2 entropy, chaotic solar dynamo and solar filament-sunspot relationship, it is concluded that the coronal activity of the high layer of the Sun described by solar filament numbers is chaotic and has very complex behaviour.

Zou, Peng; Li, Qi-Xiu; Wu, Nan

2014-01-01

80

Soil microbial biomass and activity in long-term grassland: Effects of management changes  

Microsoft Academic Search

The effects of long-term N fertilizer management history and field drainage on soil microbial biomass N and C and its activity in the surface soil of a poorly-drained pasture soil in S.W. England were examined periodically for 1 year. The immediate effects of changes in N fertilizer inputs were also determined. In general, there were few differences in the trends

R. D. Lovell; S. C. Jarvis; R. D. Bardgett

1995-01-01

81

Long term variations in the solar chromosphere -- Ca K line profiles  

NASA Astrophysics Data System (ADS)

The previous studies show that there is a lack of information on the variation of network flux with solar cycle phase and also the center of solar disc was found to show no variation with solar cycle phase (White and Livingston 1978). A study on solar variability model (Skumanich et al. 1984) shows that there is an excess component during the solar maximum phase. Therefore the above mentioned studies, forms the basis for the development of new programs (Jagdev Singh 1989) at Kodaikanal tower telescope since 1986 to monitor Ca K line profiles as a function of latitude and integrated over the visible 180° longitude. The huge database is being used to study the various parameters of the Ca K line and to study the variation of chromospheric flux as a function of solar latitude with solar cycle phase. Activity related with sunspots has been studied widely but variations in the polar regions have not been observed systematically. Our data permits to study the changes in polar regions systematically and its implications to the magnetic cycle of the Sun. Here we shall discuss the results about the variation in the chromospheric flux in terms of CaK plages, network and background flux. These variations have long and short term implications on the climatic modeling.

Sindhuja, G.

82

Solar Cycle Dynamics of Solar, Magnetospheric, and Heliospheric Particles, and Long-Term Atmospheric Coupling: SAMPEX  

NASA Technical Reports Server (NTRS)

This report summarizes science analysis activities by the SAMPEX mission science team during the period during the period July 1, 1997 through July 1, 1997. Bibliographic entries for 1996 and 1997 to date (July 1997) are included. The SAMPEX science team was extremely active, with 27 articles published or submitted to refereed journals, 17 papers published in their entirety in Conference Proceedings, and 74 contributed papers, seminars, and miscellaneous presentations. The bibliography at the end of this report constitutes the primary description of the research activity. Science highlights are given under the major activity headings, as well as other activities of the team.

Mason, G. M.; Blake, J. B.; Mewaldt, R. A.; Stone, E. C.; Baker, D. N.; vonRosenvinge, T. T.; Callis, L. B.; Hamilton, D. C.; Klecker, B.; Hovestadt, D.; Scholer, M.

1997-01-01

83

Solar Cycle Dynamics of Solar, Magnetospheric, and Heliospheric Particles, and Long-Term Atmospheric Coupling: SAMPEX  

NASA Technical Reports Server (NTRS)

This report summarizes science analysis activities by the SAMPEX mission science team during the period during the period July 1, 1997 through July 1, 1998. Bibliographic entries for 1997 and 1998 to date (July 1998) are included. The SAMPEX science team was extremely active, with 20 articles published or submitted to refereed journals, 11 papers published in their entirety in Conference Proceedings, and 49 contributed papers, seminars, and miscellaneous presentations. The bibliography at the end of this report constitutes the primary description of the research activity. Science highlights are given under the major activity headings, as well as other activities of the team.

Mason, G. M.; Blake, J. B.; Mewaldt, R. A.; Stone, E. C.; Baker, D. N.

1998-01-01

84

Implications of solar irradiance variability upon long-term changes in the Earth's atmospheric temperatures  

NASA Technical Reports Server (NTRS)

From 1979 through 1987, it is believed that variability in the incoming solar energy played a significant role in changing the Earth's climate. Using high-precision spacecraft radiometric measurements, the incoming total solar irradiance (total amount of solar power per unit area) and the Earth's mean, global atmospheric temperatures were found to vary in phase with each other. The observed irradiance and temperature changes appeared to be correlated with the 11-year cycle of solar magnetic activity. During the period from 1979 through 1985, both the irradiance and temperature decreased. From 1985 to 1987, they increased. The irradiance changed approximately 0.1 percent, while the temperature varied as much as 0.6 C. During the 1979-1987 period, the temperatures were forecasted to rise linearly because of the anthropogenic build-up of carbon dioxide and the hypothesized 'global warming', 'greenhouse effect', scenarios. Contrary to these scenarios, the temperatures were found to vary in a periodic manner in phase with the solar irradiance changes. The observed correlations between irradiance and temperature variabilily suggest that the mean, global temperature of the Earth may decline between 1990 and 1997 as solar magnetic activity decreases.

Lee, Robert B., III

1992-01-01

85

Long-term total solar irradiance variability during sunspot cycle 22  

NASA Technical Reports Server (NTRS)

Total solar irradiance measurements from the 1984-1993 Earth Radiation Budget Satellite (ERBS) active cavity radiometer and 1978-1993 Nimbus 7 transfer cavity radiometer spacecraft experiments are analyzed to detect the presence of 11-, 22-, and 80-year irradiance variability components. The analyses confirmed the existence of a significant 11-year irradiance variability component, associated with solar magnetic activity and the sunspot cycle. The analyses also suggest the presence of a 22- or 80-year variability component. The earlier Nimbus 7 and Solar Maximum Mission (SMM) spacecraft irradiance measurements decreased approximately 1.2 and 1.3 W/sq m, respectively, between 1980 and 1986. The Nimbus 7 values increased 1.2 W/sq m between 1986 and 1989. The ERBS irradiance measurements increased 1.3 W/sq m during 1986-1989, and then decreased 0.4 W/sq m (at an annual rate of 0.14 W/sq. m/yr) during 1990-1993. Considering the correlations between ERBS, Nimbus 7, and SMM irradiance trends and solar magnetic activity, the total solar irradiance should decrease to minimum levels by 1997 as solar activity decreases to minimum levels, and then increase to maximum levels by the year 2000 as solar activity rises. The ERBS measurements yielded 165.4 +/- 0.7 W/sq m as the mean irradiance value with measurement accuracies and precisions of 0.2% and 0.02%, respectively. The ERBS mean irradiance value is within 0.2% of the 1367.4, 1365.9, and 1366.9 W/sq m mean values for the SMM, Upper Atmosphere Research Satellite (UARS), and Space Shuttle Atmospheric Laboratory for Applications and Science (ATLAS 1) Solar Constant (SOLCON) active cavity radiometer spacecraft experiments, respectively. The Nimbus 7 measurements yielded 1372.1 W/sq m as the mean value with a measurement accuracy of 0.5%. Empirical irradiance model fits, based upon 10.7 -cm solar radio flux (F10) and photometric sunspot index (PSI), were used to assess the quality of the ERBS, Numbus 7, SMM, and the UARS irradiance data sets and to identify irradiance variability trends which may be caused by drifts or shifts in the spacecraft sensor responses. Comparisons among the fits and measured irradiances indicate that the Nimbus 7 radiometer response shifted by a total of 0.8 W/sq m between September 1989 and April 1990 and that the ERBS and UARS radiometers each drifted approximately 0.5 W/sq m during the first 5 months in orbit.

Lee, Robert B., III; Gibson, M. Alan; Wilson, Robert S.; Thomas, Susan

1995-01-01

86

Solar Cycle Dynamics of Solar, Magnetospheric, and Heliospheric Particles, and Long-Term Atmospheric Coupling: SAMPEX  

NASA Technical Reports Server (NTRS)

This final technical report summarizes science analysis activities by the SAMPEX mission science team during the period July 1, 1995 through September 30, 2000. Bibliographic entries for 1995 to date (October 2000) are included. The SAMPEX science team was extremely active, with 72 articles published or submitted to referred journals, 38 papers published in their entirety in Conference Proceedings, and 260 contributed papers, seminars, and miscellaneous presentations. The bibliography at the end of this report constitutes the primary description of the research activity. Science highlights are given under the major activity headings, as well as other activities of the team. One Ph.D. student, Mr. Daniel Williams, completed his thesis at California Institute of Technology based on data from the MAST instrument.

Mason, G. M.; Blake, J. B.; Mazur, J. E.; Mewaldt, R. A.; Stone, E. C.; Baker, D. N.; vonRosenvinge, T. T.; Callis, L. B.; Klecker, B.; Hovestadt, D.; Scholer, M.

2000-01-01

87

Calibration Of a Century of Polar Field Measurements and what this Tells us About the Long-term Variability of the Solar and Heliospheric Magnetic Field  

NASA Astrophysics Data System (ADS)

In addition to the well known 11-year periodicity, the solar cycle also presents long-term modulations of its amplitude and period which play a determinant role in the evolution of space weather and climate. To this date, the efforts at understanding long-term solar variability have focused on the active parts of the cycle using sunspot properties as their main source of data. However, the recent extend minimum of sunspot cycle 23 has shown us that the quiet parts of the cycle are equally important and thus long-term databases complementary to sunspot properties are necessary. Here we show how to consolidate Mount Wilson Observatory polar faculae data from four observational campaigns (1906-1964, Sheeley 1966; 1960-1975, Sheeley 1976; 1975-1990, Sheeley 1991; 1985-2007, Sheeley 2008), validate it through a comparison with facular data counted automatically from MDI intensitygrams, and calibrate it against polar field measurements taken by the Wilcox Solar Observatory (1977-2011) and average polar field and total polar flux calculated using MDI line-of-sight magnetograms (1996-2011). We also show that the consolidated polar facular measurements are in excellent agreement with both polar field and polar flux estimates, making them an ideal proxy to study the evolution of the polar magnetic field since 1906 and use this proxy to study the role of polar flux in the evolution of the solar cycle and the Heliospheric Magnetic Field (HMF).

Munoz-Jaramillo, Andres; Sheeley, N. R.; Zhang, J.; DeLuca, E. E.

2012-05-01

88

Determining the amount of physical activity needed for long-term weight control  

NASA Technical Reports Server (NTRS)

OBJECTIVE: To evaluate prospectively the influence of habitual physical activity on body weight of men and women and to develop a model that defines the role of physical activity on longitudinal weight change. DESIGN AND SETTING: Occupational cohort study conducted for a mean of 5.5 y. SUBJECTS: A total of 496 (341 male and 155 female) NASA/Johnson Space Center employees who completed the 3 month education component of the employee health-related fitness program and remained involved for a minimum of 2 y. MEASUREMENTS: Body weights were measured at baseline (T1) and follow-up (T2), and habitual physical activity was obtained from the mean of multiple ratings of the 11-point (0-10) NASA Activity Scale (NAS) recorded quarterly between T1 and T2. Other measures included age, gender, VO(2 max) obtained from maximal treadmill testing, body mass index (BMI), and body fat percentage. RESULTS: Multiple regression demonstrated that mean NAS, T1 weight, aging and gender all influence long-term T2 weight. T1 age was significant for the men only. Independently, each increase in mean NAS significantly (P<0.01) reduced T2 weight in men (b=-0.91 kg; 95% CI:-1.4 to-0.42 kg) and women (b=-2.14 kg; 95% CI:-2.93 to-1.35 kg). Mean NAS had a greater effect on T2 weight as T1 weight increased, and the relationship was dose-dependent. CONCLUSIONS: Habitual physical activity is a significant source of long-term weight change. The use of self-reported activity level is helpful in predicting long-term weight changes and may be used by health care professionals when counseling patients about the value of physical activity for weight control.

Wier, L. T.; Ayers, G. W.; Jackson, A. S.; Rossum, A. C.; Poston, W. S.; Foreyt, J. P.

2001-01-01

89

Long-term-average, solar cycle, and seasonal response of magnetospheric energetic electrons to the solar wind speed  

E-print Network

to the solar wind speed D. Vassiliadis,1 A. J. Klimas,2 S. G. Kanekal,3 D. N. Baker,3 and R. S. Weigel4. [1] Among the interplanetary activity parameters the solar wind speed is the one best correlated is parameterized by the time delay (t), measured from the time of solar wind impact, and the L shell (L). We

90

Intervention to increase physical activity in irritable bowel syndrome shows long-term positive effects  

PubMed Central

AIM: To assess the long-term effects of physical activity on irritable bowel syndrome (IBS) symptoms and on quality of life, fatigue, depression and anxiety. METHODS: Seventy-six patients from a previous randomized controlled interventional study on increased physical activity in IBS were asked to participate in this long-term follow-up study. The included patients attended one visit in which they filled out questionnaires and they underwent a submaximal cycle ergometer test. The primary end point was the change in the IBS Severity Scoring System (IBS-SSS) at baseline, i.e., before the intervention and at follow-up. The secondary endpoints were changes in quality of life, fatigue, depression and anxiety. RESULTS: A total of 39 [32 women, median age 45 (28-61) years] patients were included in this follow-up. Median follow-up time was 5.2 (range: 3.8-6.2) years. The IBS symptoms were improved compared with baseline [IBS-SSS: 276 (169-360) vs 218 (82-328), P = 0.001]. This was also true for the majority of the dimensions of psychological symptoms such as disease specific quality of life, fatigue, depression and anxiety. The reported time of physical activity during the week before the visit had increased from 3.2 (0.0-10.0) h at baseline to 5.2 (0.0-15.0) h at follow-up, P = 0.019. The most common activities reported were walking, aerobics and cycling. There was no significant difference in the oxygen uptake 31.8 (19.7-45.8) mL per min per kg at baseline vs 34.6 (19.0-54.6) mL/min per kg at follow-up. CONCLUSION: An intervention to increase physical activity has positive long-term effects on IBS symptoms and psychological symptoms.

Johannesson, Elisabet; Ringström, Gisela; Abrahamsson, Hasse; Sadik, Riadh

2015-01-01

91

Intervention to increase physical activity in irritable bowel syndrome shows long-term positive effects  

PubMed Central

AIM: To assess the long-term effects of physical activity on irritable bowel syndrome (IBS) symptoms and on quality of life, fatigue, depression and anxiety. METHODS: Seventy-six patients from a previous randomized controlled interventional study on increased physical activity in IBS were asked to participate in this long-term follow-up study. The included patients attended one visit in which they filled out questionnaires and they underwent a submaximal cycle ergometer test. The primary end point was the change in the IBS Severity Scoring System (IBS-SSS) at baseline, i.e., before the intervention and at follow-up. The secondary endpoints were changes in quality of life, fatigue, depression and anxiety. RESULTS: A total of 39 [32 women, median age 45 (28-61) years] patients were included in this follow-up. Median follow-up time was 5.2 (range: 3.8-6.2) years. The IBS symptoms were improved compared with baseline [IBS-SSS: 276 (169-360) vs 218 (82-328), P = 0.001]. This was also true for the majority of the dimensions of psychological symptoms such as disease specific quality of life, fatigue, depression and anxiety. The reported time of physical activity during the week before the visit had increased from 3.2 (0.0-10.0) h at baseline to 5.2 (0.0-15.0) h at follow-up, P = 0.019. The most common activities reported were walking, aerobics and cycling. There was no significant difference in the oxygen uptake 31.8 (19.7-45.8) mL per min per kg at baseline vs 34.6 (19.0-54.6) mL/min per kg at follow-up. CONCLUSION: An intervention to increase physical activity has positive long-term effects on IBS symptoms and psychological symptoms. PMID:25593485

Johannesson, Elisabet; Ringström, Gisela; Abrahamsson, Hasse; Sadik, Riadh

2015-01-01

92

Caregivers' difficulties in activating long-term mental illness patients with low self-esteem.  

PubMed

The aim of the study was to describe psychiatric caregivers' perceptions of self-esteem and activities for patients with long-term mental illness. The study design used a qualitative approach, based on an open lifeworld perspective. A total of 13 caregivers at four psychiatric hospital units in a large Swedish city were interviewed about their views on patients' physical activity and/or other pastimes, as well as their self-esteem and its bearing on the patients' well-being. According to the caregivers, it is up to the patients themselves to decide what they wish to occupy themselves with. In the same time the caregivers' opinions are that patients have difficulties to occupy themselves. The caregivers believe that patients' disability is based in a lack of self-esteem, commitment and capacity to realize their wishes. The caregivers in this study argue that activities are valuable for self-esteem and physical health of people with long-term mental illness. The caregivers consider that it is the patient's responsibility to initiate their needs of activities. This means that the caregivers do not use their knowledge about the importance of activities for the patient's health. Search terms: activity, caregivers, mental illness. PMID:22070619

Erdner, A; Magnusson, A

2012-03-01

93

An Approach for Long Term Forecasting with an Application to Solar Electric Energy  

Microsoft Academic Search

An approach is proposed that is useful for long term forecasting of market penetration of new technologies, fuel price and availability, business performance, etc. The central idea is to systematically solicit experts' opinion in the form of subjective probability distributions in making future projections. The approach has two basic ingredients. One is the decomposition of the problem so that each

Rakesh K. Sarin

1979-01-01

94

Long-term weathering effects on the thermal performance of the Lennox/Honeywell (liquid) solar collector  

NASA Technical Reports Server (NTRS)

The test procedures used and the results obtained during the evaluation test program of the Lennox/Honeywell double covered liquid solar collector. The tests were performed under simulated conditions, following long-term exposure to natural weathering conditions. The Lennox/Honeywell collector is a flat-plate solar collector. The absorber plate is steel with copper tubes bonded on the upper surface, and is coated with black chrome. Visual inspection of the collector indicated slight discoloration of the absorber plate. Results indicate that performance degradation had occurred. Absorptivity and/or transmissivity decreased as a result of the weathering.

1978-01-01

95

Cholinergic Pairing with Visual Activation Results in Long-Term Enhancement of Visual Evoked Potentials  

PubMed Central

Acetylcholine (ACh) contributes to learning processes by modulating cortical plasticity in terms of intensity of neuronal activity and selectivity properties of cortical neurons. However, it is not known if ACh induces long term effects within the primary visual cortex (V1) that could sustain visual learning mechanisms. In the present study we analyzed visual evoked potentials (VEPs) in V1 of rats during a 4–8 h period after coupling visual stimulation to an intracortical injection of ACh analog carbachol or stimulation of basal forebrain. To clarify the action of ACh on VEP activity in V1, we individually pre-injected muscarinic (scopolamine), nicotinic (mecamylamine), ?7 (methyllycaconitine), and NMDA (CPP) receptor antagonists before carbachol infusion. Stimulation of the cholinergic system paired with visual stimulation significantly increased VEP amplitude (56%) during a 6 h period. Pre-treatment with scopolamine, mecamylamine and CPP completely abolished this long-term enhancement, while ?7 inhibition induced an instant increase of VEP amplitude. This suggests a role of ACh in facilitating visual stimuli responsiveness through mechanisms comparable to LTP which involve nicotinic and muscarinic receptors with an interaction of NMDA transmission in the visual cortex. PMID:19543405

Kang, Jun Il; Vaucher, Elvire

2009-01-01

96

Diurnal tide in the low-latitude troposphere and stratosphere: Long-term trends and role of the extended solar minimum  

NASA Astrophysics Data System (ADS)

In the present study, long-term trends in the diurnal tide in the troposphere and stratosphere over a tropical station Gadanki (13.5°N, 79.2°E) are investigated using ERA-Interim wind and temperature products available since 1979. Suitability of the ERA-Interim data for the present study is ascertained using simultaneous radiosonde and MST radar observations over Gadanki and good consistency was found between the two. In general, diurnal tide amplitudes are found to increase from troposphere to stratosphere, as expected. Amplitude of the diurnal tide shows a long-term linear increasing trend, which becomes prominent in the stratosphere. Interestingly, convection over Gadanki also exhibits an increasing trend suggesting that they are related. Role of solar cycle on the diurnal tide is investigated by separating the tidal amplitudes during minimum and maximum of solar cycles 21, 22 and 23. Significantly higher amplitudes in the recent extended solar minimum are noticed though no consistent relation is found between solar activity and tides, in general. These results are discussed in the light of role of convection on the generation of the diurnal tide and their propagation to the higher altitudes, coupling lower and middle atmospheres. Special emphasis is made on the observed large amplitudes of the diurnal tide in the extended solar minimum while relating the observed changes to the background circulation.

Ratnam, M. Venkat; Rao, N. Venkateswara; Vedavathi, C.; Murthy, B. V. Krishna; Bhaskara Rao, S. Vijaya

2014-12-01

97

Reductions in muscle sympathetic nerve activity after long-term metoprolol for dilated cardiomyopathy: preliminary observations.  

PubMed Central

OBJECTIVE--To determine whether efferent muscle sympathetic nerve activity diminishes in subjects with dilated cardiomyopathy who improve after long term treatment with metoprolol. METHODS--Microneurographic, echocardiographic, plethysmographic, and neurohumoral data were obtained immediately before and 20 months after the addition of beta blockade in seven subjects with idiopathic dilated cardiomyopathy with clinical deterioration despite conventional treatment. RESULTS--Six subjects (three men, three women, aged 24-62 years) were restudied after a mean (SEM) of 20 (2.4) months treatment with metoprolol (45.8 (2.6) mg/d). Long term treatment was associated with decreases in left ventricular end diastolic and end systolic diameter (P < 0.005), left ventricular mass index (P < 0.05), and atrial natriuretic factor (P < 0.05), and increases in fractional shortening (P < 0.05) and mean blood pressure (P < 0.05). There was a 50% reduction in peroneal muscle sympathetic nerve activity (from 49.2 (10.1) to 24.5 (4.7) bursts/min; (P < 0.005) and a 62% decrease in calf vascular resistance (from 56.2 (4.4) to 21.2 (5.7) units; P < 0.005). This reduction in pulse synchronous nerve activity was not simply a function of bradycardia (heart rate fell from 94.2 (4.6) to 62.8 (5.7) beats/min; P < 0.005) since muscle sympathetic burst incidence also decreased (from 51 (8.7) to 37.5 (5.2) bursts/100 heart beats; P < 0.05). Similar haemodynamic improvement was observed in the seventh subject, who was switched to sotalol 200 mg/d and restudied after 20 months, but burst frequency was 50% higher and calf vascular resistance 93% higher. CONCLUSIONS--Muscle sympathetic nerve activity and calf vascular resistance decrease in patients with dilated cardiomyopathy who improve after long term treatment with metoprolol. Inhibition of central sympathetic outflow may be one mechanism by which metoprolol benefits such subjects. PMID:7488460

Rahman, M. A.; Hara, K.; Daly, P. A.; Wigle, E. D.; Floras, J. S.

1995-01-01

98

Long-term stability of dentoalveolar and skeletal changes after activator-headgear treatment.  

PubMed

The aim of this study was to analyze the long-term stability of combined activator-headgear treatment on skeletal and dental structures in Class II patients. The material comprised 26 subjects, 10 girls and 16 boys. All had a molar Class II relationship, overjet > or =6 mm, and overbite > or =5 mm. They were treated in one practice with combined activator and headgear appliances. Lateral cephalometric radiographs and dental study casts were taken before treatment (T0, mean age 11.9 years), at the end of activator-headgear treatment (T1, mean age 15.9 years), and 12-15 years out of retention (T2, mean age 28.6 years). Nineteen cephalometric and nine dental cast variables were evaluated using a paired sample t-test between T0-T1, T1-T2, and T0-T2. At T1, the majority of the cephalometric measurements showed statistically significant changes. ANB was significantly reduced by 2.3 degrees due to a significant increase in SNB, but only small changes were observed in SNA. The interincisal angle increased as a result of significant retroclination of both maxillary and mandibular incisors. All patients achieved a Class I molar relationship and a significant reduction in overjet and overbite. At T2, the results showed only slight relapse from T1. However, the relapse did not compromise the significant improvement in almost all the cephalometric and dental variables. Combined activator-headgear treatment improved the skeletal and dental conditions and the results remained stable in the long term. PMID:19477971

Lerstøl, Magnhild; Torget, Oystein; Vandevska-Radunovic, Vaska

2010-02-01

99

Impact of microbial activity on the radioactive waste disposal: long term prediction of biocorrosion processes.  

PubMed

This study emphasizes different experimental approaches and provides perspectives to apprehend biocorrosion phenomena in the specific disposal environment by investigating microbial activity with regard to the modification of corrosion rate, which in turn can have an impact on the safety of radioactive waste geological disposal. It is found that iron-reducing bacteria are able to use corrosion products such as iron oxides and "dihydrogen" as new energy sources, especially in the disposal environment which contains low amounts of organic matter. Moreover, in the case of sulphate-reducing bacteria, the results show that mixed aerobic and anaerobic conditions are the most hazardous for stainless steel materials, a situation which is likely to occur in the early stage of a geological disposal. Finally, an integrated methodological approach is applied to validate the understanding of the complex processes and to design experiments aiming at the acquisition of kinetic data used in long term predictive modelling of biocorrosion processes. PMID:24177136

Libert, Marie; Schütz, Marta Kerber; Esnault, Loïc; Féron, Damien; Bildstein, Olivier

2014-06-01

100

Exchange Protein Activated by cAMP Enhances Long-Term Memory Formation Independent of Protein Kinase A  

ERIC Educational Resources Information Center

It is well established that cAMP signaling within neurons plays a major role in the formation of long-term memories--signaling thought to proceed through protein kinase A (PKA). However, here we show that exchange protein activated by cAMP (Epac) is able to enhance the formation of long-term memory in the hippocampus and appears to do so…

Ma, Nan; Abel, Ted; Hernandez, Pepe J.

2009-01-01

101

Antioxidative enzyme and glutathione S-transferase activities in diabetic rats exposed to long-term ASA treatment  

Microsoft Academic Search

Low-dose acetylsalicylic acid (ASA) treatment is a standard therapeutic approach in diabetes mellitus for prevention of long-term vascular complications. The aim of the present work was to investigate the effect of long-term ASA administration in experimental diabetes on activities of some liver enzymes: glutathione peroxidase (GSHPx), catalase, glucose-6-phosphate dehydrogenase (G6PDH) and glutathione S-transferase (GST). Blood glucose, glycated hemoglobin, as well

E. A. Lapshina; E. Ju. Sudnikovich; Ju. Z. Maksimchik; S. V. Zabrodskaya; L. B. Zavodnik; V. L. Kubyshin; M. Nocun; P. Kazmierczak; M. Dobaczewski; C. Watala; I. B. Zavodnik

2006-01-01

102

PICARD SOL mission, a ground-based facility for long-term solar radius measurement  

NASA Astrophysics Data System (ADS)

For the last thirty years, ground time series of the solar radius have shown different variations according to different instruments. The origin of these variations may be found in the observer, the instrument, the atmosphere and the Sun. These time series show inconsistencies and conflicting results, which likely originate from instrumental effects and/or atmospheric effects. A survey of the solar radius was initiated in 1975 by F. Laclare, at the Calern site of the Observatoire de la Cˆote d'Azur (OCA). PICARD is an investigation dedicated to the simultaneous measurements of the absolute total and spectral solar irradiance, the solar radius and solar shape, and to the Sun's interior probing by the helioseismology method. The PICARD mission aims to the study of the origin of the solar variability and to the study of the relations between the Sun and the Earth's climate by using modeling. These studies will be based on measurements carried out from orbit and from the ground. PICARD SOL is the ground segment of the PICARD mission to allow a comparison of the solar radius measured in space and on ground. PICARD SOL will enable to understand the influence of the atmosphere on the measured solar radius. The PICARD Sol instrumentation consists of: SODISM II, a replica of SODISM (SOlar Diameter Imager and Surface Mapper), a high resolution imaging telescope, and MISOLFA (Moniteur d'Images SOLaires Franco-Al?erien), a seeing monitor. Additional instrumentation consists in a Sun photometer, which measures atmospheric aerosol properties, a pyranometer to measure the solar irradiance, a visible camera, and a weather station. PICARD SOL is operating since March 2011. First results from the PICARD SOL mission are briefly reported in this paper.

Meftah, M.; Irbah, A.; Corbard, T.; Morand, F.; Thuillier, G.; Hauchecorne, A.; Ikhlef, R.; Rouze, M.; Renaud, C.; Djafer, D.; Abbaki, S.; Assus, P.; Chauvineau, B.; Cissé, E. M.; Dalaudier, F.; D'Almeida, Eric; Fodil, M.; Laclare, F.; Lesueur, P.; Lin, M.; Marcovici, J. P.; Poiet, G.

2012-09-01

103

Covalent functionalization of graphene by azobenzene with molecular hydrogen bonds for long-term solar thermal storage  

PubMed Central

Reduced graphene oxide-azobenzene (RGO-AZO) hybrids were prepared via covalent functionalization for long-term solar thermal storage. Thermal barrier (?Ea) of cis to tran reversion and thermal storage (?H) were improved by molecular hydrogen bonds (H-bonds) through ortho- or para-substitution of AZO. Intramolecular H-bonds thermally stabilized cis-ortho-AZO on RGO with a long-term half-life of 5400?h (?Ea = 1.2?eV), which was much longer than that of RGO-para-AZO (116?h). RGO-para-AZO with one intermolecular H-bond showed a high density of thermal storage up to 269.8?kJ kg?1 compared with RGO-ortho-AZO (149.6?kJ kg?1) with multiple intra- and intermolecular H-bonds of AZO according to relaxed stable structures. Thermal storage in experiment was the same order magnitude to theoretical data based on ?H calculated by density functional theory and packing density. Photoactive RGO-AZO hybrid can be developed for high-performance solar thermal storage by optimizing molecular H-bonds. PMID:24247355

Feng, Yiyu; Liu, Hongpo; Luo, Wen; Liu, Enzuo; Zhao, Naiqin; Yoshino, Katsumi; Feng, Wei

2013-01-01

104

Long-term radiation effects on GaAs solar cell characteristics  

NASA Technical Reports Server (NTRS)

This report investigates preliminary design considerations which should be considered for a space experiment involving Gallium Arsenide (GaAs) solar cells. The electron radiation effects on GaAs solar cells were conducted in a laboratory environment, and a statistical analysis of the data is presented. In order to augment the limited laboratory data, a theoretical investigation of the effect of radiation on GaAs solar cells is also developed. The results of this study are empirical prediction equations which can be used to estimate the actual damage of electrical characteristics in a space environment. The experimental and theoretical studies also indicate how GaAs solar cell parameters should be designed in order to withstand the effects of electron radiation damage.

Heinbockel, J. H.; Doviak, M. J.

1978-01-01

105

The chromospherically active binary star EI Eridani II. Long-term Doppler imaging  

E-print Network

Data from 11 years of continuous spectroscopic observations of the active RS CVn-type binary star EI Eridani - gained at NSO/McMath-Pierce, KPNO/Coude Feed and during the MUSICOS 98 campaign - were used to obtain 34 Doppler maps in three spectroscopic lines for 32 epochs, 28 of which are independent of each other. Various parameters are extracted from our Doppler maps: average temperature, fractional spottedness, and longitudinal and latitudinal spot-occurrence functions. We find that none of these parameters show a distinct variation nor a correlation with the proposed activity cycle as seen from photometric long-term observations. This suggests that the photometric brightness cycle may not necessarily be due to just a cool spot cycle. The general morphology of the spot pattern remains persistent over the whole period of 11 years. A large cap-like polar spot was recovered from all our images. A high degree of variable activity was noticed near latitudes of approx. 60-70 degrees where the appendages of the polar spot emerged and dissolved.

A. Washuettl; K. G. Strassmeier; M. Weber

2008-11-19

106

Therapeutic intraspinal stimulation to generate activity and promote long-term recovery  

PubMed Central

Neuroprosthetic approaches have tremendous potential for the treatment of injuries to the brain and spinal cord by inducing appropriate neural activity in otherwise disordered circuits. Substantial work has demonstrated that stimulation applied to both the central and peripheral nervous system leads to immediate and in some cases sustained benefits after injury. Here we focus on cervical intraspinal microstimulation (ISMS) as a promising method of activating the spinal cord distal to an injury site, either to directly produce movements or more intriguingly to improve subsequent volitional control of the paretic extremities. Incomplete injuries to the spinal cord are the most commonly observed in human patients, and these injuries spare neural tissue bypassing the lesion that could be influenced by neural devices to promote recovery of function. In fact, recent results have demonstrated that therapeutic ISMS leads to modest but sustained improvements in forelimb function after an incomplete spinal cord injury (SCI). This therapeutic spinal stimulation may promote long-term recovery of function by providing the necessary electrical activity needed for neuron survival, axon growth, and synaptic stability. PMID:24578680

Mondello, Sarah E.; Kasten, Michael R.; Horner, Philip J.; Moritz, Chet T.

2014-01-01

107

Persistence and activation of malaria hypnozoites in long-term primary hepatocyte cultures.  

PubMed

Malaria relapses, resulting from the activation of quiescent hepatic hypnozoites of Plasmodium vivax and Plasmodium ovale, hinder global efforts to control and eliminate malaria. As primaquine, the only drug capable of eliminating hypnozoites, is unsuitable for mass administration, an alternative drug is needed urgently. Currently, analyses of hypnozoites, including screening of compounds that would eliminate them, can only be made using common macaque models, principally Macaca rhesus and Macaca fascicularis, experimentally infected with the relapsing Plasmodium cynomolgi. Here, we present a protocol for long-term in vitro cultivation of P. cynomolgi-infected M. fascicularis primary hepatocytes during which hypnozoites persist and activate to resume normal development. In a proof-of-concept experiment, we obtained evidence that exposure to an inhibitor of histone modification enzymes implicated in epigenetic control of gene expression induces an accelerated rate of hypnozoite activation. The protocol presented may further enable investigations of hypnozoite biology and the search for compounds that kill hypnozoites or disrupt their quiescence. PMID:24509527

Dembélé, Laurent; Franetich, Jean-François; Lorthiois, Audrey; Gego, Audrey; Zeeman, Anne-Marie; Kocken, Clemens H M; Le Grand, Roger; Dereuddre-Bosquet, Nathalie; van Gemert, Geert-Jan; Sauerwein, Robert; Vaillant, Jean-Christophe; Hannoun, Laurent; Fuchter, Matthew J; Diagana, Thierry T; Malmquist, Nicholas A; Scherf, Artur; Snounou, Georges; Mazier, Dominique

2014-03-01

108

Effects on winter circulation of short and long term solar wind changes  

NASA Astrophysics Data System (ADS)

Indices of the North Atlantic Oscillation and the Arctic Oscillation show correlations on the day-to-day timescale with the solar wind speed (SWS). Minima in the indices were found on days of SWS minima during years of high stratospheric aerosol loading. The spatial distribution of surface pressure changes during 1963-2011 with day-to-day changes in SWS shows a pattern resembling the NAO. Such a pattern was noted for year-to-year variations by Boberg and Lundstedt (2002), who compared NAO variations with the geo-effective solar wind electric field (the monthly average SWS multiplied by the average southward component, i.e., negative Bz component, of the interplanetary magnetic field). The spatial distribution of the correlations of geopotential height changes in the troposphere and stratosphere with the SWS; the geo-effective electric field (SWS?Bz); and the solar 10.7 cm flux suggests that solar wind inputs connected to the troposphere via the global electric circuit, together with solar ultraviolet irradiance acting on the stratosphere, affect regional atmospheric dynamics.

Zhou, Limin; Tinsley, Brian; Huang, Jing

2014-12-01

109

Long-term effect of ZnO nanoparticles on waste activated sludge anaerobic digestion.  

PubMed

The increasing use of zinc oxide nanoparticles (ZnO NPs) raises concerns about their environmental impacts, but the potential effect of ZnO NPs on sludge anaerobic digestion remains unknown. In this paper, long-term exposure experiments were carried out to investigate the influence of ZnO NPs on methane production during waste activated sludge (WAS) anaerobic digestion. The presence of 1 mg/g-TSS of ZnO NPs did not affect methane production, but 30 and 150 mg/g-TSS of ZnO NPs induced 18.3% and 75.1% of inhibition respectively, which showed that the impact of ZnO NPs on methane production was dosage dependant. Then, the mechanisms of ZnO NPs affecting sludge anaerobic digestion were investigated. It was found that the toxic effect of ZnO NPs on methane production was mainly due to the release of Zn(2+) from ZnO NPs, which may cause the inhibitory effects on the hydrolysis and methanation steps of sludge anaerobic digestion. Further investigations with enzyme and fluorescence in situ hybridization (FISH) assays indicated that higher concentration of ZnO NPs decreased the activities of protease and coenzyme F(420), and the abundance of methanogenesis Archaea. PMID:21917290

Mu, Hui; Chen, Yinguang

2011-11-01

110

Mouse short- and long-term locomotor activity analyzed by video tracking software.  

PubMed

Locomotor activity (LMA) is a simple and easily performed measurement of behavior in mice and other rodents. Improvements in video tracking software (VTS) have allowed it to be coupled to LMA testing, dramatically improving specificity and sensitivity when compared to the line crossings method with manual scoring. In addition, VTS enables high-throughput experimentation. While similar to automated video tracking used for the open field test (OFT), LMA testing is unique in that it allows mice to remain in their home cage and does not utilize the anxiogenic stimulus of bright lighting during the active phase of the light-dark cycle. Traditionally, LMA has been used for short periods of time (mins), while longer movement studies (hrs-days) have often used implanted transmitters and biotelemetry. With the option of real-time tracking, long-, like short-term LMA testing, can now be conducted using videography. Long-term LMA testing requires a specialized, but easily constructed, cage so that food and water (which is usually positioned on the cage top) does not obstruct videography. Importantly, videography and VTS allows for the quantification of parameters, such as path of mouse movement, that are difficult or unfeasible to measure with line crossing and/or biotelemetry. In sum, LMA testing coupled to VTS affords a more complete description of mouse movement and the ability to examine locomotion over an extended period of time. PMID:23851627

York, Jason M; Blevins, Neil A; McNeil, Leslie K; Freund, Gregory G

2013-01-01

111

Long-term non-invasive and continuous measurements of legume nodule activity.  

PubMed

Symbiotic nitrogen fixation is a process of considerable economic, ecological and scientific interest. The central enzyme nitrogenase reduces H(+) alongside N2 , and the evolving H2 allows a continuous and non-invasive in vivo measurement of nitrogenase activity. The objective of this study was to show that an elaborated set-up providing such measurements for periods as long as several weeks will produce specific insight into the nodule activity's dependence on environmental conditions and genotype features. A system was developed that allows the air-proof separation of a root/nodule and a shoot compartment. H2 evolution in the root/nodule compartment can be monitored continuously. Nutrient solution composition, temperature, CO2 concentration and humidity around the shoots can concomitantly be maintained and manipulated. Medicago truncatula plants showed vigorous growth in the system when relying on nitrogen fixation. The set-up was able to provide specific insights into nitrogen fixation. For example, nodule activity depended on the temperature in their surroundings, but not on temperature or light around shoots. Increased temperature around the nodules was able to induce higher nodule activity in darkness versus light around shoots for a period of as long as 8 h. Conditions that affected the N demand of the shoots (ammonium application, Mg or P depletion, super numeric nodules) induced consistent and complex daily rhythms in nodule activity. It was shown that long-term continuous measurements of nodule activity could be useful for revealing special features in mutants and could be of importance when synchronizing nodule harvests for complex analysis of their metabolic status. PMID:25640854

Cabeza, Ricardo A; Liese, Rebecca; Fischinger, Stephanie A; Sulieman, Saad; Avenhaus, Ulrike; Lingner, Annika; Hein, Hans; Koester, Beke; Baumgarten, Vanessa; Dittert, Klaus; Schulze, Joachim

2015-02-01

112

Leisure time physical activity and long-term cardiovascular and cancer outcomes: the Busselton Health Study.  

PubMed

The study aimed to investigate whether meeting leisure time physical activity recommendations was associated with reduced incident and fatal cancer or cardiovascular disease (CVD) in a community-based cohort of middle- to late-aged adults with long-term follow-up. At baseline, 2,320 individuals were assessed on a large number of lifestyle and clinical parameters including their level of physical activity per week, other risk factors (e.g. smoking and alcohol use) various anthropometric measures, blood tests and medical history. Individuals were linked to hospital and mortality registry data to identify future cancer and cardiovascular events (fatal and non-fatal) out to 15 years of follow-up. Cox regression analyses adjusted for relevant confounders identified a priori were used to estimate risk for all-cause, cancer-specific and CVD-specific mortality. In the full cohort an estimated 21 % decreased risk for all-cause mortality (HR 0.79; 95 % CI 0.66-0.96) and 22 % decreased risk for fatal/non-fatal CVD events (HR 0.78; 95 % CI 0.66-0.92) was associated with baseline self-reported physical activity levels of 150 min or more. After exclusion of those with chronic co-morbidities (CVD, cancer, diabetes, chronic obstructive pulmonary disease, hypertension treatment) at baseline, lower risk for fatal/non-fatal CVD events remained significantly associated with 150 min or more of physical activity (HR 0.77; 95 % CI 0.62-0.96). Results from this well established prospective community-based cohort study support the role of leisure time physical activity in reducing all-cause mortality and CVD events (fatal/nonfatal) in the broader population studied. The data also suggest that physical activity associated reductions in risk for CVD events (fatal/nonfatal) were not overly impacted by prevalent key non-communicable diseases. PMID:25354993

Gunnell, Anthony S; Knuiman, Matthew W; Divitini, Mark L; Cormie, Prue

2014-11-01

113

Lubeluzole, a novel long-term neuroprotectant, inhibits the glutamate-activated nitric oxide synthase pathway.  

PubMed

The novel drug lubeluzole, but not its (-)-R-isomer, protects against sensorimotor deficits provoked by photochemical stroke in rats. We studied the mechanism of protection of lubeluzole against glutamate toxicity in primary hippocampal cell cultures. In a model for glutamate antagonism, i.e., treatment of the cultures with compound during the glutamate trigger, lubeluzole was not protective. In contrast, after prolonged pretreatment, i.e., administration of compound to the culture for 7 days before glutamate, lubeluzole was neuroprotective. It had an IC50 of 48 nM and its R-isomer was nine times less active. Under these conditions, lubeluzole inhibited glutamate-stimulated guanosine 3',5'-cyclic monophosphate production (IC50 37 nM). Again the R-isomer was seven times less active. The compounds did not affect nitric oxide synthase activity, guanylate cyclase activity or arginine uptake. After prolonged pretreatment, lubeluzole attenuated citrulline production in the culture, which could not be compensated for by excess arginine. Because prolonged lubeluzole treatment does not inhibit glutamate-activated [Ca+2]i rise in these cultures, the findings may indicate that expression of nitric oxide synthase or levels of its cofactors were reduced. Treatment of C6 glioma cells with lubeluzole did not affect lipopolysaccharide/gamma interferon induced guanosine 3',5'-cyclic monophosphate levels, suggesting that lubeluzole does not inhibit the glial nitric oxide synthase pathway. In conclusion, the long-term neuroprotective property of lubeluzole against glutamate toxicity in hippocampal cultures is reflected by the fact of interference with the glutamateactivated nitric oxide synthase pathway. Prolonged treatment may reduce expression of nitric oxide synthase or levels of its cofactors. PMID:8930181

Lesage, A S; Peeters, L; Leysen, J E

1996-11-01

114

Long-term active antimicrobial coatings for surgical sutures based on silver nanoparticles and hyperbranched polylysine.  

PubMed

The goal of this study was to develop a long-term active antimicrobial coating for surgical sutures. To this end, two water-insoluble polymeric nanocontainers based on hyperbranched polylysine (HPL), hydrophobically modified by either using glycidyl hexadecyl ether, or a mixture of stearoyl/palmitoyl chloride, were synthesized. Highly stabilized silver nanoparticles (AgNPs, 2-5?nm in size) were generated by dissolving silver nitrate in the modified HPL solutions in toluene followed by reduction with L-ascorbic acid. Poly(glycolic acid)-based surgical sutures were dip-coated with the two different polymeric silver nanocomposites. The coated sutures showed high efficacies of more than 99.5% reduction of adhesion of living Staphylococcus aureus cells onto the surface compared to the uncoated specimen. Silver release experiments were performed on the HPL-AgNP modified sutures by washing them in phosphate buffered saline for a period of 30?days. These coatings showed a constant release of silver ions over more than 30?days. After this period of washing, the sutures retained their high efficacies against bacterial adhesion. Cytotoxicity tests using L929 mouse fibroblast cells showed that the materials are basically non-cytotoxic. PMID:23574366

Ho, Chau Hon; Odermatt, Erich K; Berndt, Ingo; Tiller, Joerg C

2013-01-01

115

Long-Term file activity patterns in a UNIX workstation environment  

NASA Technical Reports Server (NTRS)

As mass storage technology becomes more affordable for sites smaller than supercomputer centers, understanding their file access patterns becomes crucial for developing systems to store rarely used data on tertiary storage devices such as tapes and optical disks. This paper presents a new way to collect and analyze file system statistics for UNIX-based file systems. The collection system runs in user-space and requires no modification of the operating system kernel. The statistics package provides details about file system operations at the file level: creations, deletions, modifications, etc. The paper analyzes four months of file system activity on a university file system. The results confirm previously published results gathered from supercomputer file systems, but differ in several important areas. Files in this study were considerably smaller than those at supercomputer centers, and they were accessed less frequently. Additionally, the long-term creation rate on workstation file systems is sufficiently low so that all data more than a day old could be cheaply saved on a mass storage device, allowing the integration of time travel into every file system.

Gibson, Timothy J.; Miller, Ethan L.

1998-01-01

116

Long-term measurements of 36Cl to investigate potential solar influence on the decay rate  

NASA Astrophysics Data System (ADS)

Recently, Jenkins et al. [6] reported on fluctuations in the detected decay events of 36Cl which were measured with a Geiger-Müller counter. Experimental data of 32Si measured by means of an end-window gas-flow proportional counter at the Brookhaven National Laboratory show similar periodicity, albeit a different amplitude. Jenkins et al. interpret the fluctuations as evidence of solar influence on the decay rates of beta-decaying radionuclides.

Kossert, Karsten; Nähle, Ole J.

2014-03-01

117

Seasonal cycle and long-term trend of solar energy fluxes through Arctic sea ice  

NASA Astrophysics Data System (ADS)

Arctic sea ice has not only decreased in volume during the last decades, but has also changed in its physical properties towards a thinner and more seasonal ice cover. These changes strongly impact the energy budget, and might affect the ice-associated ecosystems. In this study, we quantify solar shortwave fluxes through sea ice for the entire Arctic during all seasons. To focus on sea-ice-related processes, we exclude fluxes through open water, scaling linearly with sea ice concentration. We present a new parameterization of light transmittance through sea ice for all seasons as a function of variable sea ice properties. The maximum monthly mean solar heat flux under the ice of 30 × 105 Jm-2 occurs in June, enough heat to melt 0.3 m of sea ice. Furthermore, our results suggest that 96% of the annual solar heat input through sea ice occurs during only a 4-month period from May to August. Applying the new parameterization to remote sensing and reanalysis data from 1979 to 2011, we find an increase in transmitted light of 1.5% yr-1 for all regions. This corresponds to an increase in potential sea ice bottom melt of 63% over the 33-year study period. Sensitivity studies reveal that the results depend strongly on the timing of melt onset and the correct classification of ice types. Assuming 2 weeks earlier melt onset, the annual transmitted solar radiation to the upper ocean increases by 20%. Continuing the observed transition from a mixed multi-year/first-year sea ice cover to a seasonal ice cover results in an increase in light transmittance by an additional 18%.

Arndt, S.; Nicolaus, M.

2014-11-01

118

Factors that Influence Physical Activity in Long-Term Care: Perspectives of Residents, Staff, and Significant Others  

ERIC Educational Resources Information Center

Physical activity has been linked to positive health outcomes for frail seniors. However, our understanding of factors that influence the physical activity of residents in the long-term care (LTC) setting is limited. This article describes our work with focus groups, one component of a multi-component study that examined factors influencing the…

Benjamin, Kathleen; Edwards, Nancy; Guitard, Paulette; Murray, Mary Ann; Caswell, Wenda; Perrier, Marie Josee

2011-01-01

119

SEASONAL PHOSPHATASE ACTIVITY IN THREE CHARACTERISTIC SOILS OF THE ENGLISH UPLANDS POLLUTED BY LONG-TERM ATMOSPHERIC NITROGEN DEPOSITION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Phosphomonoesterase activities were determined monthly during a seasonal cycle in three characteristic soil types of the English uplands that have been subject to long-term atmospheric nitrogen deposition. Activities (µmol para-nitrophenol per gram soil dry wt per hour) ranged between 83.9 - 307 in...

120

Long-term recording of external urethral sphincter EMG activity in unanesthetized, unrestrained rats.  

PubMed

The external urethral sphincter muscle (EUS) plays an important role in urinary function and often contributes to urinary dysfunction. EUS study would benefit from methodology for longitudinal recording of electromyographic activity (EMG) in unanesthetized animals, but this muscle is a poor substrate for chronic intramuscular electrodes, and thus the required methodology has not been available. We describe a method for long-term recording of EUS EMG by implantation of fine wires adjacent to the EUS that are secured to the pubic bone. Wires pass subcutaneously to a skull-mounted plug and connect to the recording apparatus by a flexible cable attached to a commutator. A force transducer-mounted cup under a metabolic cage collected urine, allowing recording of EUS EMG and voided urine weight without anesthesia or restraint. Implant durability permitted EUS EMG recording during repeated (up to 3 times weekly) 24-h sessions for more than 8 wk. EMG and voiding properties were stable over weeks 2-8. The degree of EUS phasic activity (bursting) during voiding was highly variable, with an average of 25% of voids not exhibiting bursting. Electrode implantation adjacent to the EUS yielded stable EMG recordings over extended periods and eliminated the confounding effects of anesthesia, physical restraint, and the potential for dislodgment of the chronically implanted intramuscular electrodes. These results show that micturition in unanesthetized, unrestrained rats is usually, but not always, associated with EUS bursting. This methodology is applicable to studying EUS behavior during progression of gradually evolving disease and injury models and in response to therapeutic interventions. PMID:24990895

LaPallo, Brandon K; Wolpaw, Jonathan R; Chen, Xiang Yang; Carp, Jonathan S

2014-08-15

121

Long-Term Atmospheric Changes Caused by the Very Large Solar Proton Event in July 2000  

NASA Technical Reports Server (NTRS)

Solar cycle 23 was accompanied by eight very large solar proton events (SPEs) between 2000 and 2005, along with numerous smaller events. The very large SPE in July 2000, which was associated with the well-known 'Bastille Day Solar Storm,' caused very substantial changes in the polar mesosphere and stratosphere. Significant downward transport of the SPE-produced NO(x) from the polar lower mesosphere and upper stratosphere during the Southern Hemisphere winter period resulted in huge enhancements (>100%) in middle stratospheric NO(x) (NO+NO2) during September 2000 in the polar vortex, which were measured by UARS HALOE (C. E. Randall et al., Geophys. Res. Lett., 28,2385-2388,2001). We have used the Whole Atmosphere Community Climate Model (WACCM) to study the longer-term impact of the July 2000 SPE, the third largest SPE period in the past 40 years. This very large SPE provided a wonderful opportunity to study the downward transport of energetic particle precipitation effects in the middle atmosphere. Not surprisingly, the WACCM-simulated polar Northern Hemisphere influences from the July (mid-summer) 2000 SPE were significant for a few months, but the constituent changes were not transported below about 20 hPa. However in the polar Southern Hemisphere (SH) region, the persistent downward transport in the vortex during the months of July-August-September resulted in significant modeled influences for about a year past the SPE. The SH odd nitrogen family, NO(y) (N, NO, NO2, NO3, N2O5, HNO3, HO2NO2, ClONO2, BrONO2), was greatly enhanced by this SPE and these increases were transported to the lower stratosphere. The SPE-enhanced polar NO(y) resulted in long-lasting ozone decreases (from catalytic NO(y) destruction of ozone) and ozone increases (from NO(y) interference in the chlorine and bromine catalytic ozone destruction cycles). These ozone changes resulted in simulated SH polar stratospheric temperature decreases (1-2 K) and increases (1-3 K)..

Jackman, C. H.; Marsh, D. R.; Garcia, R. R.; Vitt, F. M.; Randall, C. E.; Fleming, F. L.; Labow, G. J.

2007-01-01

122

Long-term Measurements of Solar Proton Fluxes (1963-present) and the Subsequent Impact on Stratospheric Constituents  

NASA Technical Reports Server (NTRS)

The fluxes of solar protons have been measured by satellites for over forty years (1963-present). Eight Interplanetary Monitoring Platform (IMP) satellites measured solar proton fluxes from 1963-1993 and five NOAA Geostationary Operational Environmental Satellites (GOES) were used for the period 1994present. These high energy solar protons precipitate on the Earth's polar atmosphere sporadically, especially during solar proton events (SPEs), which typically last a few days. Solar protons with energies greater than 30 MeV are capable of reaching the stratosphere and causing increases in odd hydrogen (HOx) and odd nitrogen (NOy) constituents at polar latitudes (greater than 60 degrees geomagnetic). The enhanced HOx leads to short-lived ozone depletion (-days) due to the short lifetime of HOx constituents. The enhanced NOy leads to long-lived ozone changes because of the long lifetime of the NOy family in the stratosphere. Several very large SPEs (August 1972, August and October 1989, July and November 2000, September and November 2001, and October 2003) over the 1963-2004 time period were simulated in the GSFC two-dimensional chemistry and transport model and were predicted to cause significant polar upper stratospheric ozone depletion greater than 10%, which lasted for several weeks past the events. Several satellite instruments (BUV, SBUV, SBW/2, SAGE II, HALOE, etc.) have shown constituent changes as a result of SPEs. Long-term (greater than 40 year) model simulations of the influence of the solar protons and satellite measurements during and after some of the very large SPEs will be shown.

Jackman, Charles H.; Fleming, Eric L.

2005-01-01

123

Long-term effects of ammonia on the behavioral activity of the aquatic snail Potamopyrgus antipodarum (Hydrobiidae, Mollusca).  

PubMed

An appropriate approach to assess the effect of toxicants on aquatic animals is to monitor behavioral endpoints, as they are a link between physiological and ecological processes. A group that can be exposed long-term to low toxic concentrations is benthic macroinvertebrates, as their mobility in aquatic ecosystems is relatively limited. Therefore, the study of behavioral long-term effects in this group is suitable from an ecological point of view, as behavioral effects can appear before mortality. During the last decades there has been an increase in ammonia concentrations in freshwater ecosystems, threatening aquatic animals. The present study focuses on the long-term effects (40 days) of nonionized ammonia on the behavioral activity of the aquatic snail Potamopyrgus antipodarum. One control and three ammonia concentrations (0.02, 0.07, and 0.13 mg N-NH(3)/L) were used in triplicate, and the activity of snails (as mean time to start normal movement) and immobility were recorded for each treatment after 0, 10, 20, 30, and 40 days of continuous exposure to nonionized ammonia. The results show that P. antipodarum presented a high tolerance to lethal long-term effects of nonionized ammonia, as no animal died during the bioassay. However, the behavioral activity of snails was a very sensitivity endpoint, as a mean nonionized ammonia concentration of 0.07 mg N-NH(3)/L affected P. antipodarum. The results are discussed and compared with the available literature on long-term effects of ammonia on freshwater macroinvertebrates. Additionally, the ammonia water quality criteria, NOECs, LOECs, and long-term LCs are discussed on the basis of the current available data for freshwater macroinvertebrates. PMID:19039513

Alonso, Alvaro; Camargo, Julio A

2009-05-01

124

Persistent activation of the zeta isoform of protein kinase C in the maintenance of long-term potentiation.  

PubMed Central

Long-term potentiation in the CA1 region of the hippocampus, a model for memory formation in the brain, is divided into two phases. A transient process (induction) is initiated, which then generates a persistent mechanism (maintenance) for enhancing synaptic strength. Protein kinase C (PKC), a gene family of multiple isozymes, may play a role in both induction and maintenance. In region CA1 from rat hippocampal slices, most of the isozymes of PKC translocated to the particulate fraction 15 sec after a tetanus. The increase of PKC in the particulate fraction did not persist into the maintenance phase of long-term potentiation. In contrast, a constitutively active kinase, PKM, a form specific to a single isozyme (zeta), increased in the cytosol during the maintenance phase. The transition from translocation of PKC to formation of PKM may help to explain the molecular mechanisms of induction and maintenance of long-term potentiation. Images Fig. 1 Fig. 3 PMID:8378304

Sacktor, T C; Osten, P; Valsamis, H; Jiang, X; Naik, M U; Sublette, E

1993-01-01

125

Prefrontal activity associated with working memory and episodic long-term memory  

Microsoft Academic Search

Many recent neuroimaging studies have highlighted the role of prefrontal regions in the sustained maintenance and manipulation of information over short delays, or working memory (WM). In addition, neuroimaging findings have highlighted the role of prefrontal regions in the formation and retrieval of memories for events, or episodic long-term memory (LTM), but it remains unclear whether these regions are distinct

Charan Ranganath; Marcia K. Johnson; Mark D’Esposito

2003-01-01

126

Long-term Variation of the Solar Diurnal Anisotropy of Galactic Cosmic Rays Observed with the Nagoya Multi-directional Muon Detector  

NASA Astrophysics Data System (ADS)

We analyze the three-dimensional anisotropy of the galactic cosmic ray (GCR) intensities observed independently with a muon detector at Nagoya in Japan and neutron monitors over four solar activity cycles. We clearly see the phase of the free-space diurnal anisotropy shifting toward earlier hours around solar activity minima in A > 0 epochs, due to the reduced anisotropy component parallel to the mean magnetic field. This component is consistent with a rigidity-independent spectrum, while the perpendicular anisotropy component increases with GCR rigidity. We suggest that this harder spectrum of the perpendicular component is due to contribution from the drift streaming. We find that the bi-directional latitudinal density gradient is positive in the A > 0 epoch, while it is negative in the A < 0 epoch, in agreement with the drift model prediction. The radial density gradient of GCRs, on the other hand, varies with a ~11 yr cycle with maxima (minima) in solar maximum (minimum) periods, but we find no significant difference between the radial gradients in the A > 0 and A < 0 epochs. The corresponding parallel mean free path is larger in A < 0 than in A > 0. We also find, however, that the parallel mean free path (radial gradient) appears to persistently increase (decrease) in the last three cycles of weakening solar activity. We suggest that simple differences between these parameters in A > 0 and A < 0 epochs are seriously biased by these long-term trends.

Munakata, K.; Kozai, M.; Kato, C.; Kóta, J.

2014-08-01

127

Long term CO2 trapping and associated leakage efficiency: the role of active faults  

NASA Astrophysics Data System (ADS)

Geological CO2 storage is viewed as a possible solution for the mitigation of increasing on-going global warming. Several pilot injection sites are already in place and numerous numerical scenarios are modeled. However, the remaining question is how effective the different kind of traps, caprocks and associated leakages are in the long term. One of the best keys to answer this question is to investigate natural CO2 fields. Here, we present the study of a CO2-reservoir, located upon the Colorado Plateau, leaking for thousands of years along normal faults. We are currently investigating i) the CO2-leakage processes from the deep to the surface, ii) the CO2 and the fluid origins, the reaction mechanisms during the transfer and finally iii) the fluid circulation time by datation. Fieldworks across a fractured zone lead us to rebuild the architecture of the CO2 path from the depth to the surface: from bleached fractures through the reservoir/caprock pile to calcium carbonate mineralization. The CO2 leaking zone migrated along the faults: traces of past and actual leakages are obvious at different points of faults evidenced by travertine occurrences. Furthermore, at a same location, proofs of episodic CO2 circulation had been found at different scales, from outcrop to thin-section scales. Detailed petrographic and isotopic analysis confirmed this result and characterized the change in fluid source. Dedicated studies on carbonated mineralization (travertine) at the surface, revealed a complex mode of formation. The travertine can be subdivided into three main types of carbonated rocks: 1) a "classical" travertine built on surface 2) horizontal and 3) vertical crosscutting veins through the first occurrence. Each of theses units is characterized by different crystallization modes and processes. Petrographic observations indicates that the travertine and the veins are mainly built of aragonite and calcite: their partition and mineral morphology can be considered as a tool to understand the paragenesis and the evolution of thermodynamic and chemical properties - P, PCO2, T, calcium saturation - of the fluids during the leakage, through mineralization time-step at the surface. In parallel, preliminary paleomagnetic studies and U/Th datating on the various cross-cutting veins constrain the laps-time of each mineralization event, leading to an estimation of flow rate evolution of one opening/sealing event. Based on these results, we will propose a numerical modeling of CO2-leakage through a faulted zone which links episodic variations of CO2-circulation to fault opening and sealing: a Dirac of CO2-input corresponding to the opening of the fault during earthquake is followed by an exponential decrease rate of the CO2 flow related to the post-seismic fault sealing by the mineralization of calcium carbonate. The model allows to evaluate the cumulative flow of CO2 releases by successive earthquakes or pressure drop linked to the long-term fault activity.

Frery, E.; Gratier, J.; Ellouz, N.; Swennen, R.; Blamart, D.; Aubourg, C.; Deschamps, P.; Faure, J.; Battani, A.

2010-12-01

128

Atmospheric science is the study of short-term weather and long-term climate, involving activities such as weather  

E-print Network

Atmospheric science is the study of short-term weather and long-term climate, involving activities such as weather forecasting, climate projections, air quality modeling, data analysis, and basic and applied. The program maintains strong ties with regional employers in both the private sector and the National Weather

Saldin, Dilano

129

Behavior Change Strategies for Successful Long-Term Weight Loss: Focusing on Dietary and Physical Activity Adherence, Not Weight Loss  

ERIC Educational Resources Information Center

This article helps Extension professionals guide individuals in a successful long-term weight loss program. A program should focus on behavioral changes (improving eating habits and physical activity), not just weight loss. In order to do this, Extension professionals should implement behavior change strategies that motivate individuals to…

Hongu, Nobuko; Kataura, Martha P.; Block, Linda M.

2011-01-01

130

Normal activation of the supplementary motor area in patients with Parkinson's disease undergoing long-term treatment with levodopa  

Microsoft Academic Search

Regional cerebral blood flow (rCBF) changes in cortical motor areas were measured during a movement of the dominant right hand in 15 patients with Parkinson's disease deprived of their usual levodopa treatment, in 11 patients with Parkinson's disease undergoing long-term treatment with levodopa, and in 15 normal volunteers. The supplementary motor areas were significantly activated in the normal subjects and

O Rascol; U Sabatini; F Chollet; N Fabre; J M Senard; J L Montastruc; P Celsis; J P Marc-Vergnes; A Rascol

1994-01-01

131

Receptor-mediated activation of protein kinase C in hippocampal long-term potentiation: Facts, problems and implications  

Microsoft Academic Search

During the last decade hippocampal long-term potentiation has become one of the most frequently used models to study cellular mechanisms of learning and memory. Receptor-mediated activation of protein kinase C is thought to be involved in LTP stabilisation. In the present review 1.1. the molecular structure and activation mechanisms of PKC isoenzymes,2.2. the biochemical evidences for PKC activation after induction

Frank Angenstein; Sabine Staak

1997-01-01

132

Long Term Seismic Observation in Mariana by OBSs : Activity of Deep Earthquakes  

Microsoft Academic Search

In order to obtain the deep arc structural image of Mariana, a large-scale seismic observation by using 58 long-term ocean bottom seismometers (LTOBS) has been started since June 2003 for about one year. It is a part of the MARGINS program (US-JAPAN COLLABORATIVE RESEARCH: MULTI-SCALE SEISMIC IMAGING OF THE MARIANA SUBDUCTION FACTORY), and the aim of this observation is the

H. Shiobara; K. Mochizuki; S. Ohki; T. Kanazawa; Y. Fukao; H. Sugioka; K. Suyehiro

2003-01-01

133

Deciphering the Long-Term Trend of Atlantic Basin Intense Hurricanes: More Active Versus Less Active During the Present Epoch  

NASA Technical Reports Server (NTRS)

During the interval of 1944-1997, 120 intense hurricanes (i.e., those of category 3 or higher on the Saffir-Simpson hurricane damage potential scale) were observed in the Atlantic basin, having an annual frequency of 0-7 events per year, being more active prior to the mid 1960's than thereafter (hence a possible two-state division: more active versus less active), and being preferentially lower during El Nino years as compared to non-El Nino years. Because decadal averages of the frequency of intense hurricanes closely resemble those of average temperature anomalies for northern hemispheric and global standards and of the average temperature at the Armagh Observatory (Northern Ireland), a proxy for climatic change, it is inferred that the long-term trends of the annual frequency of intense hurricanes and temperature may be statistically related. Indeed, on the basis of 4- and 10-yr moving averages, one finds that there exists strong linear associations between the annual frequency of intense hurricanes in the Atlantic basin and temperature (specially, when temperature slightly leads). Because the long-term leading trends of temperature are now decidedly upward, beginning about the mid 1980's, it is inferred that the long-term consequential trends of the annual frequency of intense hurricanes should now also be upward, having begun near 1990, suggesting that a return to the more active state probably has already occurred. However, because of the anomalous El Nino activity of the early to mid 1990's, the switch from the less active to the more active state essentially went unnoticed (a marked increase in the number of intense hurricanes was not observed until the 1995 and 1996 hurricane seasons, following the end of the anomalous El Nino activity). Presuming that a return to the more active state has, indeed, occurred, one expects the number of seasonal intense hurricanes during the present epoch (continuing through about 2012) to usually be higher than average (i.e., greater than or equal to 2), except during El Nino-related seasons when the number usually will be less than average.

Wilson, Robert M.

1998-01-01

134

Hippocampal, but not amygdala, activity at encoding correlates with long-term, free recall of nonemotional information  

PubMed Central

Participation of two medial temporal lobe structures, the hippocampal region and the amygdala, in long-term declarative memory encoding was examined by using positron emission tomography of regional cerebral glucose. Positron emission tomography scanning was performed in eight healthy subjects listening passively to a repeated sequence of unrelated words. Memory for the words was assessed 24 hr later with an incidental free recall test. The percentage of words freely recalled then was correlated with glucose activity during encoding. The results revealed a striking correlation (r = 0.91, P < 0.001) between activity of the left hippocampal region (centered on the dorsal parahippocampal gyrus) and word recall. No correlation was found between activity of either the left or right amygdala and recall. The findings provide evidence for hippocampal involvement in long-term declarative memory encoding and for the view that the amygdala is not involved with declarative memory formation for nonemotional material. PMID:9826730

Alkire, Michael T.; Haier, Richard J.; Fallon, James H.; Cahill, Larry

1998-01-01

135

Hot Jupiters and Hot Spots: The Short- and Long-Term Chromospheric Activity on Stars with Giant Planets  

NASA Astrophysics Data System (ADS)

We monitored the chromospheric activity in the Ca II H and K lines of 13 solar-type stars (including the Sun): 8 of them over 3 years at the Canada-France-Hawaii Telescope (CFHT) and 5 in a single run at the Very Large Telescope (VLT). A total of 10 of the 13 targets have close planetary companions. All of the stars observed at the CFHT show long-term (months to years) changes in H and K intensity levels. Four stars display short-term (days) cyclical activity. For two, HD 73256 and ?1 Cet, the activity is likely associated with an active region rotating with the star; however, the flaring in excess of the rotational modulation may be associated with a hot Jupiter. A planetary companion remains a possibility for ?1 Cet. For the other two, HD 179949 and ? And, the cyclic variation is synchronized to the hot Jupiter's orbit. For both stars this synchronicity with the orbit is clearly seen in two out of three epochs. The effect is only marginal in the third epoch at which the seasonal level of chromospheric activity had changed for both stars. Short-term chromospheric activity appears weakly dependent on the mean K line reversal intensities for the sample of 13 stars. In addition, a suggestive correlation exists between this activity and the Mpsini of the star's hot Jupiter. Because of their small separation (<=0.1 AU), many of the hot Jupiters lie within the Alfvén radius of their host stars, which allows a direct magnetic interaction with the stellar surface. We discuss the conditions under which a planet's magnetic field might induce activity on the stellar surface and why no such effect was seen for the prime candidate, ? Boo. This work opens up the possibility of characterizing planet-star interactions, with implications for extrasolar planet magnetic fields and the energy contribution to stellar atmospheres. Based on observations collected at the Canada-France-Hawaii Telescope operated by the National Research Council of Canada, the Centre National de la Recherche Scientifique of France, and the University of Hawaii, as well as data from the European Southern Observatory's Very Large Telescope, Chile (programme ESO 73.C-0694).

Shkolnik, E.; Walker, G. A. H.; Bohlender, D. A.; Gu, P.-G.; Kürster, M.

2005-04-01

136

Long-term effects of municipal solid waste compost application on soil enzyme activities and microbial biomass  

Microsoft Academic Search

A long-term field experiment utilising barley received four different treatments prior to sowing: municipal solid waste (MSW) compost at either 20tha?1 (C20) or 80tha?1 (C80); cow manure (MA) at 20tha?1; mineral fertilizer (MIN) or NPK (400kgha?1); and NH4NO3 (150kgha?1). The effects of these applications on soil enzyme activities and microbial biomass at crop harvest were measured after nine years. In

J. C Garc??a-Gil; C Plaza; P Soler-Rovira; A Polo

2000-01-01

137

Energetic auroral and polar ion outflow at DE 1 altitudes: Magnitude, composition, magnetic activity dependence, and long-term variations  

Microsoft Academic Search

Data from Dynamics Explorer 1 Energetic Ion Composition Spectrometer (DE 1 EICS) in the period from September 1981 to May 1984 were used to determine the mass composition, magnitude, magnetic activity dependence, long-term variations, and topology (MLT-invariant latitude distribution) of energetic (0.01-17 keV\\/el) terrestrial outflow. The September 1981 to May 1984 period coincided with the declining phase of the current

A. W. Yau; E. G. Shelley; W.K. Peterson; L. Lenchyshyn

1985-01-01

138

A Semi-Quantitative Method to Denote Generic Physical Activity Phenotypes from Long-Term Accelerometer Data – The ATLAS Index  

PubMed Central

Background Physical activity is inversely correlated to morbidity and mortality risk. Large cohort studies use wearable accelerometer devices to measure physical activity objectively, providing data potentially relevant to identify different activity patterns and to correlate these to health-related outcome measures. A method to compute relevant characteristics of such data not only with regard to duration and intensity, but also to regularity of activity events, is necessary. The aims of this paper are to propose a new method – the ATLAS index (Activity Types from Long-term Accelerometric Sensor data) – to derive generic measures for distinguishing different characteristic activity phenotypes from accelerometer data, to propose a comprehensive graphical representation, and to conduct a proof-of-concept with long-term measurements from different devices and cohorts. Methods The ATLAS index consists of the three dimensions regularity (reg), duration (dur) and intensity (int) of relevant activity events identified in long-term accelerometer data. It can be regarded as a 3D vector and represented in a 3D cube graph. 12 exemplary data sets of three different cohort studies with 99,467 minutes of data were chosen for concept validation. Results Five archetypical activity types are proposed along with their dimensional characteristics (insufficiently active: low reg, int and dur; busy bee: low dur and int, high reg; cardio-active: medium reg, int and dur, endurance athlete: high reg, int and dur; and weekend warrior: high int and dur, low reg). The data sets are displayed in one common graph, indicating characteristic differences in activity patterns. Conclusion The ATLAS index incorporates the relevant regularity dimension apart from the widely-used measures of duration and intensity. Along with the 3D representation, it allows to compare different activity types in cohort study populations, both visually and computationally using vector distance measures. Further research is necessary to validate the ATLAS index in order to find normative values and group centroids. PMID:23667631

Marschollek, Michael

2013-01-01

139

Forecasting life: a study of activity cycles in low-mass stars: lessons from long-term stellar light curves.  

PubMed

Magnetic activity cycles are indirect traces of magnetic fields and can provide an insight on the nature and action of stellar dynamos and stellar magnetic activity. This, in turn, can determine local space weather and activity effects on stellar habitable zones. Using photometric monitoring of low-mass stars, we study the presence and properties of their magnetic activity cycles. We introduce long-term light curves of our sample stars, and discuss the properties of the observed trends, especially at spectral types where stars are fully convective (later than M3). PMID:22729352

Kafka, Stella

2012-06-01

140

Comparison of Two Voltage-Sensitive Dyes and Their Suitability for Long-Term Imaging of Neuronal Activity  

PubMed Central

One of the key approaches for studying neural network function is the simultaneous measurement of the activity of many neurons. Voltage-sensitive dyes (VSDs) simultaneously report the membrane potential of multiple neurons, but often have pharmacological and phototoxic effects on neuronal cells. Yet, to study the homeostatic processes that regulate neural network function long-term recordings of neuronal activities are required. This study aims to test the suitability of the VSDs RH795 and Di-4-ANEPPS for optically recording pattern generating neurons in the stomatogastric nervous system of crustaceans with an emphasis on long-term recordings of the pyloric central pattern generator. We demonstrate that both dyes stain pyloric neurons and determined an optimal concentration and light intensity for optical imaging. Although both dyes provided sufficient signal-to-noise ratio for measuring membrane potentials, Di-4-ANEPPS displayed a higher signal quality indicating an advantage of this dye over RH795 when small neuronal signals need to be recorded. For Di-4-ANEPPS, higher dye concentrations resulted in faster and brighter staining. Signal quality, however, only depended on excitation light strength, but not on dye concentration. RH795 showed weak and slowly developing phototoxic effects on the pyloric motor pattern as well as slow bleaching of the staining and is thus the better choice for long-term experiments. Low concentrations and low excitation intensities can be used as, in contrast to Di-4-ANEPPS, the signal-to-noise ratio was independent of excitation light strength. In summary, RH795 and Di-4-ANEPPS are suitable for optical imaging in the stomatogastric nervous system of crustaceans. They allow simultaneous recording of the membrane potential of multiple neurons with high signal quality. While Di-4-ANEPPS is better suited for short-term experiments that require high signal quality, RH795 is a better candidate for long-term experiments since it has only minor effects on the motor pattern. PMID:24124505

Preuss, Stephanie; Stein, Wolfgang

2013-01-01

141

Addressing solar modulation and long-term uncertainties in scaling secondary cosmic rays for in situ cosmogenic nuclide applications [rapid communication  

NASA Astrophysics Data System (ADS)

Solar modulation affects the secondary cosmic rays responsible for in situ cosmogenic nuclide (CN) production the most at the high geomagnetic latitudes to which CN production rates are traditionally referenced. While this has long been recognized (e.g., D. Lal, B. Peters, Cosmic ray produced radioactivity on the Earth, in: K. Sitte (Ed.), Handbuch Der Physik XLVI/2, Springer-Verlag, Berlin, 1967, pp. 551-612 and D. Lal, Theoretically expected variations in the terrestrial cosmic ray production rates of isotopes, in: G.C. Castagnoli (Ed.), Proceedings of the Enrico Fermi International School of Physics 95, Italian Physical Society, Varenna 1988, pp. 216-233), these variations can lead to potentially significant scaling model uncertainties that have not been addressed in detail. These uncertainties include the long-term (millennial-scale) average solar modulation level to which secondary cosmic rays should be referenced, and short-term fluctuations in cosmic ray intensity measurements used to derive published secondary cosmic ray scaling models. We have developed new scaling models for spallogenic nucleons, slow-muon capture and fast-muon interactions that specifically address these uncertainties. Our spallogenic nucleon scaling model, which includes data from portions of 5 solar cycles, explicitly incorporates a measure of solar modulation ( S), and our fast- and slow-muon scaling models (based on more limited data) account for solar modulation effects through increased uncertainties. These models improve on previously published models by better sampling the observed variability in measured cosmic ray intensities as a function of geomagnetic latitude, altitude, and solar activity. Furthermore, placing the spallogenic nucleon data in a consistent time-space framework allows for a more realistic assessment of uncertainties in our model than in earlier ones. We demonstrate here that our models reasonably account for the effects of solar modulation on measured secondary cosmic ray intensities, within the uncertainties of our combined source datasets. We also estimate solar modulation variations over the last 11.4 ka from a recent physics-based sunspot number reconstruction derived from tree-ring 14C data. This approximation suggests that spallogenic nucleon scaling factors in our model for sea level and high geomagnetic latitudes can differ by up to ˜ 10%, depending on the time step over which the model sunspot numbers are averaged. The potential magnitude of this difference supports our contention that incorporating long-term solar modulation into secondary cosmic ray scaling is important. Although millennial-scale solar modulation clearly requires further study, we believe it is reasonable at present to use our S value record for scaling spallogenic nucleons during the last 11.4 ka, and the weighted mean S value for that period of 0.950 for longer exposure times. By accounting for solar modulation effects on the global variations in nucleon and muon fluxes, these models thus provide a useful framework on which to base CN production rate scaling functions.

Lifton, Nathaniel A.; Bieber, John W.; Clem, John M.; Duldig, Marc L.; Evenson, Paul; Humble, John E.; Pyle, Roger

2005-10-01

142

A long-term perspective on anthropogenic activities and management strategies in a prairie wetland  

NASA Astrophysics Data System (ADS)

Multiple stressors to shallow lake/wetland ecosystems have the ability to control the relative stability of alternative states (clear, macrophyte-dominated or turbid, algal dominated). As a consequence, the use of remedial biomanipulations to induce trophic cascades and shift a turbid lake to a clear state is often only a temporary solution. Here we show the instability of short-term manipulations in the shallow Lake Christina (a Class V wetland in the prairie ecoregion of western Minnesota, USA) is governed by the long-term state following a regime shift in the lake. During the modern, managed period of the lake, three top-down manipulations (fish kills) were undertaken inducing temporary (5-10 years) unstable clear-water states. Paleoecological remains of diatoms, along with proxies of primary production (total chlorophyll a and total organic carbon accumulation rate) and trophic state (total P) from sediment records clearly show a single regime shift in the lake during the early 1950s; following this shift, the functioning of the lake ecosystem is dominated by a persistent turbid state. We find that multiple stressors contributed to the regime shift. First, the lake began to eutrophy (from agricultural land use and/or increased waterfowl populations), leading to a dramatic increase in primary production. Soon after, the construction of a dam in 1936 effectively doubled the depth of the lake, compounded by increases in regional humidity; this resulted in an increase in planktivorous and benthivorous fish reducing phytoplankton grazers. These factors further conspired to increase the stability of a turbid regime during the modern managed period, such that switches to a clear-water state were inherently unstable and the lake consistently returned to a turbid state. We conclude that while top-down manipulations have had measurable impacts on the lake state, they have not been effective in providing a return to an ecosystem similar to the stable historical period. Our work offers an example of a well-studied ecosystem forced by multiple stressors into a new long-term managed period, where manipulated clearwater states are temporary, managed features.

Hobbs, J. M.; Hobbs, W.; LaFrancois, T.; Edlund, M.; Theissen, K. M.; Zimmer, K.; Hanson, M.

2012-12-01

143

Effect of short- and long-term salinity on the activities of antioxidative enzymes and lipid peroxidation in tomato roots  

Microsoft Academic Search

Changes in the antioxidative enzyme activities (SOD, CuZnSOD, GSH-Px, GST), as well as TBARS content in 5-week-old tomato\\u000a (Lycopersicon\\u000a esculentum Mill. cv “Perkoz”) roots were examined 1, 3 h (short-term stress) and 1–14 days (long-term stress) after a single application\\u000a of 50 mM (mild stress) and 150 mM NaCl (severe stress). The severe stress caused an increase in GST, GSH-Px and SODs activities\\u000a from

Magdalena Gapi?ska; Maria Sk?odowska; Barbara Gabara

2008-01-01

144

GABAergic Activities Control Spike Timing- and Frequency-Dependent Long-Term Depression at Hippocampal Excitatory Synapses  

PubMed Central

GABAergic interneuronal network activities in the hippocampus control a variety of neural functions, including learning and memory, by regulating ? and ? oscillations. How these GABAergic activities at pre- and postsynaptic sites of hippocampal CA1 pyramidal cells differentially contribute to synaptic function and plasticity during their repetitive pre- and postsynaptic spiking at ? and ? oscillations is largely unknown. We show here that activities mediated by postsynaptic GABAARs and presynaptic GABABRs determine, respectively, the spike timing- and frequency-dependence of activity-induced synaptic modifications at Schaffer collateral-CA1 excitatory synapses. We demonstrate that both feedforward and feedback GABAAR-mediated inhibition in the postsynaptic cell controls the spike timing-dependent long-term depression of excitatory inputs (“e-LTD”) at the ? frequency. We also show that feedback postsynaptic inhibition specifically causes e-LTD of inputs that induce small postsynaptic currents (<70?pA) with LTP-timing, thus enforcing the requirement of cooperativity for induction of long-term potentiation at excitatory inputs (“e-LTP”). Furthermore, under spike-timing protocols that induce e-LTP and e-LTD at excitatory synapses, we observed parallel induction of LTP and LTD at inhibitory inputs (“i-LTP” and “i-LTD”) to the same postsynaptic cells. Finally, we show that presynaptic GABABR-mediated inhibition plays a major role in the induction of frequency-dependent e-LTD at ? and ? frequencies. These observations demonstrate the critical influence of GABAergic interneuronal network activities in regulating the spike timing- and frequency-dependences of long-term synaptic modifications in the hippocampus. PMID:21423508

Nishiyama, Makoto; Togashi, Kazunobu; Aihara, Takeshi; Hong, Kyonsoo

2010-01-01

145

SWAP OBSERVATIONS OF THE LONG-TERM, LARGE-SCALE EVOLUTION OF THE EXTREME-ULTRAVIOLET SOLAR CORONA  

SciTech Connect

The Sun Watcher with Active Pixels and Image Processing (SWAP) EUV solar telescope on board the Project for On-Board Autonomy 2 spacecraft has been regularly observing the solar corona in a bandpass near 17.4 nm since 2010 February. With a field of view of 54 × 54 arcmin, SWAP provides the widest-field images of the EUV corona available from the perspective of the Earth. By carefully processing and combining multiple SWAP images, it is possible to produce low-noise composites that reveal the structure of the EUV corona to relatively large heights. A particularly important step in this processing was to remove instrumental stray light from the images by determining and deconvolving SWAP's point-spread function from the observations. In this paper, we use the resulting images to conduct the first-ever study of the evolution of the large-scale structure of the corona observed in the EUV over a three year period that includes the complete rise phase of solar cycle 24. Of particular note is the persistence over many solar rotations of bright, diffuse features composed of open magnetic fields that overlie polar crown filaments and extend to large heights above the solar surface. These features appear to be related to coronal fans, which have previously been observed in white-light coronagraph images and, at low heights, in the EUV. We also discuss the evolution of the corona at different heights above the solar surface and the evolution of the corona over the course of the solar cycle by hemisphere.

Seaton, Daniel B.; De Groof, Anik; Berghmans, David; Nicula, Bogdan [Royal Observatory of Belgium-SIDC, Avenue Circulaire 3, B-1180 Brussels (Belgium); Shearer, Paul [Department of Mathematics, 2074 East Hall, University of Michigan, 530 Church Street, Ann Arbor, MI 48109-1043 (United States)

2013-11-01

146

Long-term Trends in Interplanetary Magnetic Field Strength and Solar Wind Structure during the 20th Century  

NASA Technical Reports Server (NTRS)

Lockwood et al have recently reported an approximately 40% increase in the radial component of the interplanetary magnetic field (IMF) at Earth between 1964 and 1996. We argue that this increase does not constitute a secular trend but is largely the consequence of lower than average fields during solar cycle 20 (1964-1976) in comparison with surrounding cycles. For times after 1976 the average IMF strength has actually decreased slightly. Examination of the cosmic ray intensity, an indirect measure of the IMF strength, over the last five solar cycles (19-23) also indicates that cycle averages of the IMF strength have been relatively constant since approximately 1954. We also consider the origin of the well-documented increase in the geomagnetic alphaalpha index that occurred primarily during the first half of the twentieth century. We surmise that the coronal mass ejection (CME) rate for recent solar cycles was approximately twice as high as that for solar cycles 100 years ago. However, this change in the CME rate and the accompanying increase in 27-day recurrent storm activity reported by others are unable to account completely for the increase in alphaalpha. Rather, the CMEs and recurrent high-speed streams at the beginning of the twentieth century must have been embedded in a background of slow solar wind that was less geoeffective (having, for example, lower IMF strength and/or flow speed) than its modern counterpart.

Richardson, I. G.; Cliver, E. W.; Cane, H. V.; White, Nicholas E. (Technical Monitor)

2002-01-01

147

Cationic oligo-p-phenylene ethynylenes form complexes with surfactants for long-term light-activated biocidal applications.  

PubMed

Cationic oligo-p-phenylene ethynylenes are highly effective light-activated biocides that deal broad-spectrum damage to a variety of pathogens, including bacteria. A potential problem arising in the long-term usage of these compounds is photochemical breakdown, which nullifies their biocidal activity. Recent work has shown that these molecules complex with oppositely-charged surfactants, and that the resulting complexes are protected from photodegradation. In this manuscript, we determine the biocidal activity of an oligomer and a complex formed between it and sodium dodecyl sulfate. The complexes are able to withstand prolonged periods of irradiation, continuing to effectively kill both Gram-negative and Gram-positive bacteria, while the oligomer by itself loses its biocidal effectiveness quickly in the presence of light. In addition, damage and stress responses induced by these biocides in both E. coli and S. aureus are discussed. This work shows that complexation with surfactants is a viable method for long-term light-activated biocidal applications. PMID:24149833

Hill, Eric H; Pappas, Harry C; Evans, Deborah G; Whitten, David G

2014-02-01

148

Effect of the long-term care prevention project on the motor functions and daily life activities of the elderly  

PubMed Central

[Purpose] The purpose of this study was to verify the effects of the long-term care prevention project and develop an effective program. [Subjects] A total of 81 elderly people (age, 79 ± 5.1?years; height, 149.2 ± 9.2?cm; weight, 54.2 ± 11.4?kg). [Methods] Grip, knee extension muscular strength, 10?m walking speed, and Timed Up and Go time were measured for evaluation of motor functions, and the “Locomo 25”, a 25-question risk assessment questionnaire, was used as the judgment criterion for evaluation of daily life activities, with measurements being taken at the beginning of the project and after three months. [Results] In the motor functions evaluation, significant differences were observed in 10?m walking speed, Timed Up and Go time, and knee extension strength. In the daily life activities evaluation, scores for pain, rising movement, standing movement, indoor walking, outdoor walking, and fear of falling were significantly reduced. In addition, a significant correlation was also observed between motor functions and daily life activities. [Conclusion] The result of this study indicated that the long-term care prevention project is effective in maintaining or improving muscular strength and mitigating pain in the elderly and that it is an effective program for maintaining daily life activities. We were also able to show that it would be effective to develop programs with a low exercise intensity that can be performed on a continuing by the elderly. PMID:25642073

Wada, Yoshihiro; Sakuraba, Keisyoku; Kubota, Atsushi

2015-01-01

149

A Wearable Sensor for Unobtrusive, Long-Term Assessment of Electrodermal Activity  

E-print Network

Electrodermal activity (EDA) is a sensitive index of sympathetic nervous system activity. Due to the lack of sensors that can be worn comfortably during normal daily activity and over extensive periods of time, research ...

Poh, Ming-Zher

150

Alterations in antioxidant enzyme activities and proline content in pea leaves under long-term drought stress.  

PubMed

The effects of long-term drought stress on chlorophyll, proline, protein and hydrogen peroxide (H2O2) contents, malondialdehyde (MDA) in terms of lipid peroxidation and on the changes in the activities of antioxidant enzymes such as superoxide dismutase (SOD, EC 1.15.1.1), ascorbate peroxidase (APX, EC 1.11.1.11), catalase (CAT, EC 1.11.1.6) and peroxidase (POX; EC 1.11.1.7) in the leaves of pea (Pisum sativum L.) were studied in field conditions. Chlorophyll and protein contents in leaves decreased significantly with increased drought stress. The proline content increased markedly under water deficit. MDA amounts were elevated as a result of water shortage, whereas H(2)O(2) content changed slightly in pea leaves exposed to drought stress. Drought stress markedly enhanced the activities of SOD, CAT and POX but slightly changed the activity of APX. We conclude that in field conditions, long-term water shortage increased the susceptibility to drought in peas. PMID:23047611

Karata?, Ilhami; Öztürk, Lokman; Demir, Yavuz; Unlükara, Ali; Kurunç, Ahmet; Düzdemir, Oral

2014-09-01

151

A Review of the Recent NASA Long-Term Orbital Debris Environment Projection and Active Debris Removal Modeling Activities  

NASA Technical Reports Server (NTRS)

The NASA Orbital Debris Program Office (ODPO) developed a high fidelity debris evolutionary model, LEGEND (a LEO-to-GEO Environment Debris model), in 2004 to enhance its capability to better model the near-Earth environment. LEGEND can mimic the growth of the historical debris population and project it into the future based on user-defined scenarios. The first major LEGEND study concluded that even without any future launches, the LEO population would continue to increase due to mutual collisions among existing objects. In reality, the increase will be worse than this prediction because of ongoing satellite launches and unexpected major breakups. Even with a full implementation of the commonly-adopted mitigation measures, the LEO population growth is inevitable. To preserve the near-Earth environment for future generations, active debris removal (ADR) must be considered. A follow-up LEGEND ADR study was completed recently. The main results indicate that (1) the mass and collision probability of each object can be used to establish an effective removal selection criterion and (2) a removal rate of 5 objects per year is sufficient to stabilize the LEO environment. Due to the limitation of removal techniques, however, different target selection criteria (in size, altitude, inclination, etc.) may be more practical. A careful evaluation of the effectiveness of different proposed techniques must be carried out to maximize the long-term benefit to the environment.

Liou, J.C.

2009-01-01

152

Solar Activity  

NSDL National Science Digital Library

This educational brief provides an overview of solar activity, including a description of Earth's magnetosphere and of various solar phenomena such as the solar wind, Coronal Mass Ejections (CMEs), sunspots, solar flares, and others. A list of links to additional material is also provided.

153

Modified 27-nt dsRNAs with dramatically enhanced stability in serum and long-term RNAi activity.  

PubMed

The present study describes improved properties of 27-nt dsRNAs over 21-nt siRNAs, and accents on the possibility to use their modifications and conjugates for direct long-term gene silencing in viable cells and animals, avoiding conventional transfectants. Using a Renilla Luciferase gene-silencing system and cultured cell lines, we established that 27-nt dsRNAs possessed about three to five times higher "long-term" RNAi activity than 21-nt siRNAs and 21-nt dsRNAs. Moreover, if RNA duplexes were preincubated with cell-cultured medium for several hours before their transfection in cells, 21-mer completely lost its RNAi effect, while 27-mer, its amino modifications, thiol modifications, and cholesterol conjugates manifested a strong gene silencing. In attempts to clarify the reason(s) for the higher RNAi activity of 27-nt dsRNAs, we found that they were approximately 100 times more stable than 21-nt siRNA and 21-nt dsRNA in cell-cultured medium supplemented with 10% inactivated serum, approximately 50 times more stable in 90% inactivated serum, and approximately six times more stable in active serum. The 5' sense modification was selected as the most stable, accessible to Dicer, and with highest RNAi potential. The RNAi activity of 5' sense modifications was higher even than the activity of nonmodified 27-nt dsRNA. The 5' sense amino modification also did not influence the activity of 21-nt siRNA, right overhang 25/27-nt (R25D/27), and 25D/27-nt RNAs. The stability of 5' sense modified R25D/27-nt and 25D/27-nt RNAs in serum was lower than that of blunt 27-nt dsRNA. However, these asymmetric RNAs were more active than modified and nonmodified blunt 27-nt dsRNAs, which demonstrates the superiority of the asymmetric design. The 5' sense modifications were considered as most appropriate for conjugation with small signal molecules to facilitate the intracellular delivery of RNA duplex, to preserve its RNAi capacity, and to ensure a possibility for rapid long-term gene silencing in viable cells and animals. The 5' sense conjugation with cholesterol approved this assumption. PMID:17894530

Kubo, Takanori; Zhelev, Zhivko; Ohba, Hideki; Bakalova, Rumiana

2007-01-01

154

Long-term study of cloud condensation nuclei (CCN) activation of the atmospheric aerosol in Vienna  

PubMed Central

During a total of 11 months, cloud condensation nuclei (CCN at super-saturation S 0.5%) and condensation nuclei (CN) concentrations were measured in the urban background aerosol of Vienna, Austria. For several months, number size distributions between 13.22 nm and 929 nm were also measured with a scanning mobility particle spectrometer (SMPS). Activation ratios (i.e. CCN/CN ratios) were calculated and apparent activation diameters obtained by integrating the SMPS size distributions. Variations in all CCN parameters (concentration, activation ratio, apparent activation diameter) are quite large on timescales of days to weeks. Passages of fronts influenced CCN parameters. Concentrations decreased with the passage of a front. No significant differences were found for fronts from different sectors (for Vienna mainly north to west and south to east). CCN concentrations at 0.5% S ranged from 160 cm?3 to 3600 cm?3 with a campaign average of 820 cm?3. Activation ratios were quite low (0.02–0.47, average: 0.13) and comparable to activation ratios found in other polluted regions (e.g. Cubison et al., 2008). Apparent activation diameters were found to be much larger (campaign average: 169 nm, range: (69–370) nm) than activation diameters for single-salt particles (around 50 nm depending on the salt). Contrary to CN concentrations, which are influenced by source patterns, CCN concentrations did not exhibit distinct diurnal patterns. Activation ratios showed diurnal variations counter-current to the variations of CN concentrations. PMID:21977003

Burkart, J.; Steiner, G.; Reischl, G.; Hitzenberger, R.

2011-01-01

155

Mineralogical impact on long-term patterns of soil nitrogen and phosphorus enzyme activities  

NASA Astrophysics Data System (ADS)

Soil chronosequences provide a unique opportunity to study microbial activity over time in mineralogical diverse soils of different ages. The main objective of this study was to test the effect of mineralogical properties, nutrient and organic matter availability over whole soil pro-files on the abundance and activity of the microbial communities. We focused on microbio-logical processes involved in nitrogen and phosphorus cycling at the 120,000-year Franz Josef soil chronosequence. Microbial abundances (microbial biomass and total cell counts) and enzyme activities (protease, urease, aminopeptidase, and phosphatase) were determined and related to nutrient contents and mineralogical soil properties. Both, microbial abundances and enzyme activities decreased with soil depth at all sites. In the organic layers, microbial biomass and the activities of N-hydrolyzing enzymes showed their maximum at the intermediate-aged sites, corresponding to a high aboveground biomass. In contrast, the phosphatase activity increased with site age. The activities of N-hydrolyzing enzymes were positively correlated with total carbon and nitrogen contents, whereas the phosphatase activity was negatively correlated with the phosphorus content. In the mineral soil, the enzyme activities were generally low, thus reflecting the presence of strongly sorbing minerals. Sub-strate-normalized enzyme activities correlated negatively to clay content as well as poorly crystalline Al and Fe oxyhydroxides, supporting the view that the evolution of reactive sec-ondary mineral phases alters the activity of the microbial communities by constraining sub-strate availability. Our data suggest a strong mineralogical influence on nutrient cycling par-ticularly in subsoil environments.

Mikutta, Robert; Turner, Stephanie; Meyer-Stüve, Sandra; Guggenberger, Georg; Dohrmann, Reiner; Schippers, Axel

2014-05-01

156

Diet-Induced Changes in AChE Activity after Long-Term Exposure  

Microsoft Academic Search

In the present study we investigated a potential mechanism by which high sugar (HS) and high fat (HF) diets could affect acetylcholinesterase (AChE) activity. The treatment with HS and HF diet was done for six months on male and female rats. The results showed decreased hippocampal AChE activity in male and females receiving HS and HF diets (HS 24% and

Rosilene R. Kaizer; Adriane C. da Silva; Vera M. Morsch; Maisa C. Corrêa; Maria R. C. Schetinger

2004-01-01

157

AGE-DEPENDENT LONG-TERM ADAPTATION OF CRAYFISH PHASIC MOTOR AXON SYNAPSES TO ALTERED ACTIVITY  

Microsoft Academic Search

Crustacean tonic and phasic motoneurons have neuromuscular synaptic properties corresponding with their functional requirements. Phasic axon synapses produce large excitatory postsynaptic potentials (EPSPs) which depress rapidly during repetitive activation. Tonic axon synapses generally produce smaller EPSPs which are more resistant to fatigue. To test whether nerve impulse activity of the motoneuron plays a role in the establishment of these synaptic

G. A. LNENICKA; H. L. ATWOOD

158

Long-term Observation of Soil Creep Activity around a Landslide Scar  

EPA Science Inventory

Rate of sediment infilling into landslide scars by soil creep is needed to estimate the timing of subsequent landslide activity at a particular site. However, knowledge about the spatial distribution of its activity around the landslide scar is scarce. Additionally, there are few...

159

Barriers to Physical Activity for People with Long-Term Neurological Conditions: A Review Study  

ERIC Educational Resources Information Center

People with disability are insufficiently physically active for health. This study identified the volume, quality, and findings of research that exposes environmental and personal barriers of physical activity participation for people with neurological conditions. CINAHL, Sport Discus, EMBASE, Medline, and AMED were systematically searched between…

Mulligan, Hilda F.; Hale, Leigh A.; Whitehead, Lisa; Baxter, G. David

2012-01-01

160

Long-term cycling behavior of asymmetric activated carbon\\/MnO 2 aqueous electrochemical supercapacitor  

Microsoft Academic Search

Activated carbon–MnO2 hybrid electrochemical supercapacitor cells have been assembled and characterized in K2SO4 aqueous media. A laboratory cell achieved 195,000 cycles with stable performance. The maximal cell voltage was 2V associated with 21±2Fg?1 of total composite electrode materials (including activated carbon and MnO2, binder and conductive additive) and an equivalent serie resistance (ESR) below 1.3?cm2. Long-life cycling was achieved by

Thierry Brousse; Pierre-Louis Taberna; Olivier Crosnier; Romain Dugas; Philippe Guillemet; Yves Scudeller; Yingke Zhou; Frédéric Favier; Daniel Bélanger; Patrice Simon

2007-01-01

161

Long-Term Global Morphology of Gravity Wave Activity Using UARS Data  

NASA Technical Reports Server (NTRS)

Progress in research into the global morphology of gravity wave activity using UARS data is described for the period March-June, 1998. Highlights this quarter include further progress in the analysis and interpretation of CRISTA temperature variances; model-generated climatologies of mesospheric gravity wave activity using the HWM-93 wind and temperature model; and modeling of gravity wave detection from space-based platforms. Preliminary interpretations and recommended avenues for further analysis are also described.

Eckermann, Stephen D.; Bacmeister, Julio T.; Wu, Dong L.

1998-01-01

162

Long-term (solar cycle) and seasonal variations of upflowing ionospheric ion events at de 1 altitudes  

Microsoft Academic Search

A statistical analysis is presented of the long-term variations of upflowing ionosphere ion (UFI) occurrence morphology in the high-altitude (8000-23,300 km) auroral and polar cap ionosphere, using data from the Dynamics Explorer 1 Energetic Ion Composition Spectrometer from 1981 to 1984. The study is based on over 100,000 data samples, each consisting of pitch angle distributions of H\\/sup +\\/ and

A. W. Yau; P. H. Beckwith; W.K. Peterson; E. G. Shelley

1985-01-01

163

Predictors of long-term change of a physical activity promotion programme in primary care  

PubMed Central

Background Further research is needed to improve the evidence regarding determinants of physical activity (PA) as a crucial step to plan higher effective intervention strategies. The goal of the present study is to identify socio-demographic and clinical characteristics of primary care (PHC) insufficiently active patients that are associated with longitudinal changes in the level of physical activity. Methods Longitudinal analysis of baseline socio-demographic and clinical predictors of physical activity change in insufficiently active PHC patients who participated in a PA-promoting multi-centre randomized clinical trial conducted from October 2003 through March 2006. The primary outcome measure was the self-reported physical activity assessed with the 7-day Physical Activity Recall (PAR), at baseline, 6, 12 and 24 months. Baseline covariates included sex, age, social class, anthropometric measures and other cardiovascular risk factors or associated diseases (Diabetes, HTA, tobacco use, etc.), and stage of readiness to change PA. Generalized linear mixed models were used to estimate longitudinal association of studied variables on PA change over the three follow-up measurements. Results A total of 3691 patients (85% of the 4317 recruited in the trial) with at least one follow-up measurement were included in the longitudinal analysis. At baseline, analysed patients (mean age: 50.6 years; 64.6% women) devoted 34.7 minutes and 2.36 metabolic equivalent hours per week (MET.h/week) to moderate and vigorous physical activity. Older age, male gender, higher social class, lower BMI, diagnosis of diabetes or hypertension, and measurement season were significant predictors of PA longitudinal change. The effect of baseline readiness to change on PA dose was modified by time, showing a positive gradient in favour of those with more readiness to change that increases significantly at 12 and 24 months (p-value interaction < .0001). Conclusions Identified baseline characteristics such as readiness to change and risk factors can guide physicians to prioritize time and intervention efforts for maximizing their impact on insufficiently active PHC patients. PMID:24491081

2014-01-01

164

Reviewing or Retrieving: What Activity Best Promotes Long-Term Retention?  

ERIC Educational Resources Information Center

Research studies repeatedly emphasize the importance of vocabulary capabilities to a large variety of academic activities. This study compared a learning strategy that exclusively involved the visual review of vocabulary word-definition pairs to a strategy that, in addition, prompted participants to attempt free-recall retrieval of words to match…

Lindgren, Paul D.

2012-01-01

165

Long-Term Fitness Training Improves the Circadian Rest-Activity Rhythm in Healthy Elderly Males  

Microsoft Academic Search

In old age, the circadian timing system loses optimal functioning. This process is even accelerated in Alzheimer's disease. Because pharmacological treatment of day-night rhythm disturbances usually is not very effective and may have considerable side effects, nonpharmacological treatments deserve attention. Bright light therapy has been shown to be effective. It is known from animal studies that increased activity, or an

Eus J. W. Van Someren; Cees Lijzenga; Majid Mirmiran; Dick F. Swaab

1997-01-01

166

Long-term trends and interannual variability in tropical cyclone activity over the western North Pacific  

Microsoft Academic Search

While Landsea et al. (1996) show that the number of intense Atlantic hurricanes is on the decrease, the trend of tropical cyclone activity over the western North Pacific is found to be just the opposite. For the period 1959 to 1994, the number of tropical storms and typhoons went through a period of decrease and then an increase, showing an

Johnny C. L. Chan; Jiu-en Shi

1996-01-01

167

Effect of trace amounts of polyacrylamide (PAM) on long-term performance of activated sludge.  

PubMed

This study aims at evaluating the impacts of PAM addition on activated sludge performance. Four lab-scale sequencing batch reactors (SBRs), each with a working volume of 3L, were investigated with different PAM concentrations. Experiments were conducted with varying organic loading rate and the sludge volume index (SVI), particle size, zeta potential, specific oxygen uptake rate (SOUR), mixed liquor suspended solids (MLSS), COD and ammonium removal efficiency were monitored over a 105-day period. The results showed that all of the PAM addition not only improved the removal efficiencies of COD and ammonium, but also exhibited some advantages on sludge performance. It was found that the sludge performance of settling property, flocculation and microbial activity increased with increasing concentration of PAM. However, high level of PAM (1mg/L) led to the formation of large amounts of loose-structure flocs, which eliminated dissolved oxygen transfer and caused the sludge disintegration, resulting in bad settleability and lower microbial activity. In this way, when the dosage of PAM was 0.1mg/L, the sludge had the best settling property and activity. PMID:21367524

Luo, Yuan-ling; Yang, Zhao-hui; Xu, Zheng-yong; Zhou, Ling-jun; Zeng, Guang-ming; Huang, Jing; Xiao, Yong; Wang, Li-ke

2011-05-15

168

Long-Term Heavy Ketamine Use is Associated with Spatial Memory Impairment and Altered Hippocampal Activation  

PubMed Central

Ketamine, a non-competitive N-methyl-d-aspartate receptor antagonist, is rising in popularity as a drug of abuse. Preliminary evidence suggests that chronic, heavy ketamine use may have profound effects on spatial memory but the mechanism of these deficits is as yet unclear. This study aimed to examine the neural mechanism by which heavy ketamine use impairs spatial memory processing. In a sample of 11 frequent ketamine users and 15 poly-drug controls, matched for IQ, age, years in education. We used fMRI utilizing an ROI approach to examine the neural activity of three regions known to support successful navigation; the hippocampus, parahippocampal gyrus, and the caudate nucleus during a virtual reality task of spatial memory. Frequent ketamine users displayed spatial memory deficits, accompanied by and related to, reduced activation in both the right hippocampus and left parahippocampal gyrus during navigation from memory, and in the left caudate during memory updating, compared to controls. Ketamine users also exhibited schizotypal and dissociative symptoms that were related to hippocampal activation. Impairments in spatial memory observed in ketamine users are related to changes in medial temporal lobe activation. Disrupted medial temporal lobe function may be a consequence of chronic ketamine abuse and may relate to schizophrenia-like symptomatology observed in ketamine users. PMID:25538631

Morgan, Celia J. A.; Dodds, Chris M.; Furby, Hannah; Pepper, Fiona; Fam, Johnson; Freeman, Tom P.; Hughes, Emer; Doeller, Christian; King, John; Howes, Oliver; Stone, James M.

2014-01-01

169

Long-term fitness training improves the circadian rest-activity rhythm in healthy elderly males.  

PubMed

In old age, the circadian timing system loses optimal functioning. This process is even accelerated in Alzheimer's disease. Because pharmacological treatment of day-night rhythm disturbances usually is not very effective and may have considerable side effects, nonpharmacological treatments deserve attention. Bright light therapy has been shown to be effective. It is known from animal studies that increased activity, or an associated process, also strongly affects the circadian timing system, and the present study addresses the question of whether an increased level of physical activity may improve circadian rhythms in elderly. In the study, 10 healthy elderly males were admitted to a fitness training program for 3 months. The circadian rest-activity rhythm was assessed by means of actigraphy before and after the training period and again 1 year after discontinuation. As a control for possible seasonal effects, repeated actigraphic recordings were performed during the same times of the year as were the pre and post measurements in a control group of 8 healthy elderly males. Fitness training induced a significant reduction in the fragmentation of the rest-activity rhythm. Moreover, the fragmentation of the rhythm was negatively correlated with the level of fitness achieved after the training. No seasonal effect was found. Previous findings in human and animal studies are reviewed, and several possible mechanisms involved in the effect of fitness training on circadian rhythms are discussed. The results suggest that fitness training may be helpful in elderly people suffering from sleep problems related to circadian rhythm disturbances. PMID:9090568

Van Someren, E J; Lijzenga, C; Mirmiran, M; Swaab, D F

1997-04-01

170

The agitation-activity interface of people with dementia in long-term care  

Microsoft Academic Search

The purpose of this study was to examine agitated behaviors of people with dementia relative to time and activity variables. This descriptive study involved a sample of 420 units of 30-minute time periods collected in a longterm care setting. The highest agitation scores occurred during the evening (F = 3.93, p = 0.009). Agitation scores were significantly higher when the

Christine R. Kovach; Andrea Matovina Schlidt

2001-01-01

171

Activation of MAPK Is Necessary for Long-Term Memory Consolidation Following Food-Reward Conditioning  

ERIC Educational Resources Information Center

Although an important role for the mitogen-activated protein kinase (MAPK) has been established for memory consolidation in a variety of learning paradigms, it is not known if this pathway is also involved in appetitive classical conditioning. We address this question by using a single-trial food-reward conditioning paradigm in the freshwater…

Ribeiro, Maria J.; Schofield, Michael G.; Kemenes, Ildiko; O'Shea, Michael; Kemenes, Gyorgy; Benjamin, Paul R.

2005-01-01

172

Implications of Subzero Metabolic Activity on Long-Term Microbial Survival in Terrestrial  

E-print Network

by chemical (i.e., via hydrolysis and oxidation) and ionizing radiation­induced damage to chromosomal DNA demonstrate the physiological potential for DNA metabolism at �158C and sug- gest a sufficient activity degradation over geological time. Key Words: Extraterrestrial life--Radiation resistance--Cryosphere-- DNA

Christner, Brent C.

173

Long-term growth of human WGA-activated T-lymphocytes without feeder cells.  

PubMed

Human wheat germ agglutinin (WGA)-activated T-lymphocytes from either peripheral blood or spleen could be propagated for several weeks in the presence of culture supernatants from human mononuclear cells obtained after a 1-day stimulation with WGA and after a subsequent 3-day culture without mitogen. The continuous T-cell growth in this culture system required alternate exposition of the cells to the above supernatants, both with and without WGA, but proceeded in the absence of feeder cells. After 3 weeks of propagation most cells displayed the CD4+ phenotype, expressed IL2 receptors, and responded to PHA, Con A, and WGA. It has been shown that WGA-activated T-cells could be cloned by limiting dilution and propagated using the above culture system. PMID:2569939

Siwicki, J K

1989-09-01

174

Long-Term Global Morphology of Gravity Wave Activity Using UARS Data  

NASA Technical Reports Server (NTRS)

This is the first quarter's report on research to extract global gravity-wave data from satellite data and to model those observations synoptically. Preliminary analysis of global maps of extracted middle atmospheric temperature variance from the CRISTA instrument is presented, which appear to contain gravity-wave information. Corresponding simulations of global gravity-wave and mountain-wave activity during this mission period are described using global ray-tracing and mountain-wave models, and interesting similarities among simulated data and CRISTA data are noted. Climatological simulations of mesospheric gravity-wave activity using the HWM-03 wind-temperature climatology are also reported, for comparison with UARS MLS data. Preparatory work on modeling of gravity wave observations from space-based platforms and subsequent interpretation of the MLS gravity-wave product are also described. Preliminary interpretation and relation to the research objectives are provided, and further action for the next quarter's research is recommended.

Eckermann, Stephen D.; Bacmeister, Julio T.; Wu, Dong L.

1998-01-01

175

Depressive Symptoms Among Older Adults: Long-Term Reduction After a Physical Activity Intervention  

Microsoft Academic Search

We examined the effects of two physical activity modes on depressive symptoms over a 5-year period among older adults and\\u000a change in physical self-esteem as a mediator of changes in depressive symptoms. Formerly sedentary, older adults (N?=?174) were randomly assigned into 6-month conditions of either walking or low-intensity resistance\\/flexibility training.\\u000a Depressive symptoms and physical self-esteem were measured before and after

Robert W. Motl; James F. Konopack; Edward McAuley; Steriani Elavsky; Gerald J. Jerome; David X. Marquez

2005-01-01

176

Long-term ¹³?Cs activity monitoring of mushrooms in forest ecosystems of the Czech Republic.  

PubMed

This paper reports on results of activity mass concentration analyses performed in various forest mushrooms in the Czech Republic within 1986 and 2011. The estimated effective half-life of (137)Cs and its environmental half-life (i.e. the effective half-life minus the effect of physical decay) were found to be 5.6 ± 0.6 and 6.9 ± 0.7 y, respectively. Non-homogeneity in (137)Cs surface contamination over the country's territory and fungus species-based (137)Cs accumulation capacity then account for a span of up to 4 orders of magnitude in activity mass concentrations measured each year after the Chernobyl accident. The highest geometric activity mass concentration (Bq kg(-1) of dry weight) means of (137)Cs (obtained from samples between years 2004 and 2011) were measured in Suillaceae (1050 Bq kg(-1)) and Boletus badius (930 Bq kg(-1)), the lowest in Agaricus (1 Bq kg(-1)). The geometric mean of all mushrooms amounted to 230 Bq kg(-1), being 440 Bq kg(-1) in Boletales, 150 Bq kg(-1) in Russulales and 21 Bq kg(-1) in Agaricales. Geometric standard deviation levels were generally high. The highest Cs accumulation capacity was observed in Boletales (namely in Suillaceae), while the lowest in Agaricales, being over 3 orders of magnitude lower than in Suillaceae. PMID:23838098

Škrkal, J; Rulík, P; Fantínová, K; Burianová, J; Helebrant, J

2013-12-01

177

Long-term lidar observations of wintertime gravity wave activity over northern Sweden  

NASA Astrophysics Data System (ADS)

This paper presents an analysis of gravity wave activity over northern Sweden as deduced from 18 years of wintertime lidar measurements at Esrange (68° N, 21° E). Gravity wave potential energy density (GWPED) was used to characterize the strength of gravity waves in the altitude regions 30-40 km and 40-50 km. The obtained values exceed previous observations reported in the literature. This is suggested to be due to Esrange's location downwind of the Scandinavian mountain range and due to differences in the various methods that are currently used to retrieve gravity wave parameters. The analysis method restricted the identification of the dominating vertical wavelengths to a range from 2 to 13 km. No preference was found for any wavelength in this window. Monthly mean values of GWPED show that most of the gravity waves' energy dissipates well below the stratopause and that higher altitude regions show only small dissipation rates of GWPED. Our analysis does not reproduce the previously reported negative trend in gravity wave activity over Esrange. The observed inter-annual variability of GWPED is connected to the occurrence of stratospheric warmings with generally lower wintertime mean GWPED during years with major stratospheric warmings. A bimodal GWPED occurrence frequency indicates that gravity wave activity at Esrange is affected by both ubiquitous wave sources and orographic forcing.

Ehard, B.; Achtert, P.; Gumbel, J.

2014-11-01

178

Transient translocation of protein kinase C? in hippocampal long-term potentiation depends on activation of metabotropic glutamate receptors  

Microsoft Academic Search

Protein kinase C has been implicated in long-term regulation of cellular functions including induction and maintenance of hippocampal long-term potentiation. In the present study the time-course of long-term potentiation-induced translocation of Ca2+-dependent protein kinase C isoenzymes (PKC?\\/? and PKC?) was investigated. Quantitative immunoblot analysis was used to measure translocation of these isoenzymes between cytosolic, membrane-associated and membrane-inserted fraction at 5,

F. Angenstein; G. Riedel; K. G. Reymann; S. Staak

1999-01-01

179

Total knee replacement in young, active patients. Long-term follow-up and functional outcome.  

PubMed

We reviewed our experience with total knee arthroplasties performed between 1977 and 1992 in patients who were fifty-five years old or less to determine the appropriate management for younger patients who have severe osteoarthrosis. One hundred and fourteen knee replacements were performed in eighty-eight patients who were an average of fifty-one years old (range, twenty-two to fifty-five years old). All of the operations were performed by one of the two senior ones of us (J. N. I. or W. N. S.) with the use of cementing techniques. A posterior stabilized, posterior cruciate-substituting design was used for all but one replacement, for which a semiconstrained total condylar prosthesis was used. Six knees (four patients) were lost to follow-up. Follow-up data for the remaining 108 knees (eighty-four patients) were used to perform the survivorship analysis. One hundred and three unrevised knees (eighty patients) were available for clinical evaluation with the scoring systems of The Hospital for Special Surgery and the Knee Society at an average of eight years (range, three to eighteen years) postoperatively; thirty-six knees were followed for more than ten years. In addition, the activity levels of the patients were assessed with the activity score of Tegner and Lysholm. Radiographs were examined for evidence of loosening of the component. At the latest follow-up examination, the average knee score according to the system of The Hospital for Special Surgery had improved from 55 points preoperatively to 92 points. According to the system of the Knee Society, the average knee score was 94 points and the average functional score was 89 points. The result for all 103 knees was good or excellent according to the knee scores of The Hospital for Special Surgery and the Knee Society. Ninety-seven knees (94 per cent) had good or excellent function according to the functional score of the Knee Society. The average activity score of Tegner and, Lysholm improved from 1.3 points (range, 0 to 4 points) preoperatively to 3.5 points (range, 1 to 6 points) at the latest follow-up examination. All but two patients had improvement in the activity score postoperatively, and nineteen (24 per cent) of the eighty patients had an activity score of at least 5 points, indicating regular participation in activities such as tennis, skiing, bicycling, or strenuous farm or construction work. Nine (9 per cent) of the 103 knees had non-progressive tibial radiolucent lines. Two patients had a revision because of late infection, and one patient had revision of a well fixed tibial component because of wear of the polyethylene. In addition, three patellar components were revised for loosening, and one spacer was exchanged to treat instability. With failure defined as revision of either the femoral or the tibial component, the over-all rate of survival was 94 per cent at eighteen years. When the three patellar revisions were included in the failures, the survival rate was 90 per cent at eighteen years. When the exchange of the spacer was also included in the failures, the survival rate was 87 per cent at eighteen years. We consider arthroplasty with cementing of a posterior stabilized total knee prosthesis to be effective operative treatment with durable results for osteoarthrosis in younger patients when other, less invasive measures have failed. Within the average eight-year follow-up interval of this study, polyethylene wear, osteolysis, and loosening of the conforming posterior cruciate-substituting prosthesis were not major problems for these younger, active patients, although it is possible that this observation could change with an even longer duration of follow-up. PMID:9111404

Diduch, D R; Insall, J N; Scott, W N; Scuderi, G R; Font-Rodriguez, D

1997-04-01

180

Changing patterns of the long-term activity of the intermediate polar V1223 Sgr  

NASA Astrophysics Data System (ADS)

High and low states represent a large variety of features in the optical activity of some types of cataclysmic variables. Here, we examine them in the intermediate polar V1223 Sgr. We use the photographic observations from the Bamberg Observatory and from Garnavich and Szkody, and the CCD ASAS-3 and NSVS data. One plate or CCD image was usually obtained per night. These data span 78 years. We use the histograms of brightness to set the separation between the high and low states in V1223 Sgr at the level of 13.9 mag(B). The profile of this statistical distribution is dominated by a broad bump with the peak-to-peak amplitude of more than 1 mag(B). This is the result of co-adding various episodes of the high states, sometimes with the brightness varying on a timescale of months even during a single episode. The high state is not any uniquely defined level of brightness. Groups of the low states represent tails from such bumps rather than forming specific levels of brightness. The fuzzy boundaries of the bright side of the statistical distributions of brightness show that the system cannot find equilibrium of the mass transfer even in the high state. We show that V1223 Sgr underwent a large change of its high/low state activity; we ascribe it to the changes of the stellar activity of the donor. The episodes of the low states with mutually similar depth and profile were observed to recur with a cycle of 1092 days in the data mapping the years from 1999 to 2009; this behavior was discordant with the typical recurrence times present before. In our scenario, this cycle is driven by the changing aspect of some structure (e.g. a sequence of star spots migrating across the L1 point) on the donor. Because of the differential rotation of the donor, this configuration cyclically influences the mass flow to the accretion disk.

Šimon, Vojt?ch

2014-11-01

181

Cognitive testing of physical activity and acculturation questions in recent and long-term Latino immigrants  

PubMed Central

Background We ascertained the degree to which language (English versus Spanish), and residence time in the US influence responses to survey questions concerning two topics: self-reported acculturation status, and recent physical activity (PA). This topic is likely to be of general interest because of growing numbers of immigrants in countries worldwide. Methods We carried out qualitative (cognitive) interviews of survey items on acculturation and physical activity on 27 Latino subjects from three groups: (a) In Spanish, of those of low residence time (less than five years living in the U.S.) (n = 9); (b) In Spanish, of those of high residence time (15 or more years in the U.S) (n = 9); and (c) in English, of those of high residence time (n = 9). Results There were very few language translation problems; general question design defects and socio-cultural challenges to survey responses were more common. Problems were found for both acculturation and PA questions, with distinct problem types for the two question areas. Residence time/language group was weakly associated with overall frequency of problems observed: low residence time/Spanish (86%), high residence time/Spanish (67%), and English speaking groups (62%). Conclusions Standardized survey questions related to acculturation and physical activity present somewhat different cognitive challenges. For PA related questions, problems with such questions were similar regardless of subject residence time or language preference. For acculturation related questions, residence time/language or education level influenced responses to such questions. These observations should help in the interpretation of survey results for culturally diverse populations. PMID:20707902

2010-01-01

182

Squid have nociceptors that display widespread long-term sensitization and spontaneous activity after bodily injury.  

PubMed

Bodily injury in mammals often produces persistent pain that is driven at least in part by long-lasting sensitization and spontaneous activity (SA) in peripheral branches of primary nociceptors near sites of injury. While nociceptors have been described in lower vertebrates and invertebrates, outside of mammals there is limited evidence for peripheral sensitization of primary afferent neurons, and there are no reports of persistent SA being induced in primary afferents by noxious stimulation. Cephalopod molluscs are the most neurally and behaviorally complex invertebrates, with brains rivaling those of some vertebrates in size and complexity. This has fostered the opinion that cephalopods may experience pain, leading some governments to include cephalopods under animal welfare laws. It is not known, however, if cephalopods possess nociceptors, or whether their somatic sensory neurons exhibit nociceptive sensitization. We demonstrate that squid possess nociceptors that selectively encode noxious mechanical but not heat stimuli, and that show long-lasting peripheral sensitization to mechanical stimuli after minor injury to the body. As in mammals, injury in squid can cause persistent SA in peripheral afferents. Unlike mammals, the afferent sensitization and SA are almost as prominent on the contralateral side of the body as they are near an injury. Thus, while squid exhibit peripheral alterations in afferent neurons similar to those that drive persistent pain in mammals, robust changes far from sites of injury in squid suggest that persistently enhanced afferent activity provides much less information about the location of an injury in cephalopods than it does in mammals. PMID:23761897

Crook, Robyn J; Hanlon, Roger T; Walters, Edgar T

2013-06-12

183

Long-term Global Morphology of Gravity Wave Activity Using UARS Data  

NASA Technical Reports Server (NTRS)

An extensive body of research this quarter is documented. Further methodical analysis of temperature residuals in Cryogenic Limb Array Etalon Spectrometer (CLAES) Version 8 level 3AT data show signatures during December 1992 at middle and high northern latitudes that, when compared to Naval Research Laboratory/Mountain Wave Forecast Model (NRL)/(MWFM) mountain wave hindcasts, reveal evidence of long mountain waves in these data over Eurasia, Greenland, Scandinavia and North America. The explicit detection of gravity waves in limb-scanned Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) temperatures is modeled at length, to derive visibility functions. These insights are used to convert CRISTA gravity wave temperature residuals into data that more closely resemble gravity wave fluctuations detected in data from other satellite instruments, such as Microwave Limb Sounder (MLS), Limb Infrared Monitor of the Stratosphere (LIMS) and Global Positioning System/Meteorology (GPS)/(MET). Finally, newly issued mesospheric temperatures from inversion of CRISTA 15gin emissions are analyzed using a new method that uses separate Kalman fits to the ascending and descending node data. This allows us to study global gravity wave amplitudes at two local times, 12 hours apart. In the equatorial mesosphere, where a large diurnal tidal temperature signal exists, we see modulations of gravity wave activity that are consistent with gravity wave-tidal interactions produced by tidal temperature variability.

Eckermann, Stephen D.; Jackman, C. (Technical Monitor)

2000-01-01

184

Overnight transduction with foamyviral vectors restores the long-term repopulating activity of Fancc?/? stem cells  

PubMed Central

Fanconi anemia (FA) is a complex genetic disorder characterized by congenital abnormalities, bone marrow failure, and myeloid malignancies. Identification of 13 FA genes has been instrumental to explore gene transfer technologies aimed at correction of autologous FA-deficient stem cells. To date, 3 human FA stem cell gene therapy trials with standard 4-day transduction protocols using gammaretroviral vectors failed to provide clinical benefit. In addition, 2- to 4 day ex vivo manipulation of bone marrow from mice containing a disruption of the homologue of human FANCC (Fancc) results in a time-dependent increase in apoptosis and a risk for malignant transformation of hematopoietic cells. Here, we show that a 14-hour transduction period allows a foamyviral vector construct expressing the human FANCC cDNA to efficiently transduce murine FA stem cells with 1 to 2 proviral integrations per genome. Functionally, the repopulating activity of Fancc?/? stem cells from reconstituted mice expressing the recombinant FANCC transgene was comparable with wild-type controls. Collectively, these data provide evidence that short-term transduction of c-kit+ cells with a foamyviral vector is sufficient for functional correction of a stem cell phenotype in a murine FA model. These data could have implications for future gene therapy trials for FA patients. PMID:18684868

Si, Yue; Pulliam, Anna C.; Linka, Yvonne; Ciccone, Samantha; Leurs, Cordula; Yuan, Jin; Eckermann, Olaf; Fruehauf, Stefan; Mooney, Sean

2008-01-01

185

Long term validation of Robust Satellite Techniques (RST) for thermal volcanic activity monitoring  

NASA Astrophysics Data System (ADS)

A multi-temporal scheme of satellite data analysis, named RST (Robust Satellite Techniques), already successfully used to study and monitor several active volcanoes, has recently been tested on a long time series of NOAA-AVHRR records acquired over Mount Etna area for a full assessment of its performances. Satellite records acquired at different time of pass (e.g. day/night, winter/summer), from 1995 to 2008 (14 years of satellite records analyzed), processed following RST prescriptions, have been strictly validated using ground based information reported in the volcano bulletins freely available on the web. In this work results of this detailed validation analysis will be presented, discussing performances of such an approach for an automatic satellite monitoring of thermal volcanic features. Moreover, RST capabilities in detecting even abrupt changes in thermal signal related to the beginning of new eruptive events, by using data provided by geostationary satellite like MSG-SEVIRI, will be investigated, for a possible implementation of such an approach within an integrated Early Warning System devoted to volcanic hazard mitigation.

Marchese, Francesco; Filizzola, Carolina; Genzano, Nicola; Mazzeo, Giuseppe; Paciello, Rossana; Pergola, Nicola; Tramutoli, Valerio

2010-05-01

186

Long-term weathering effects on the thermal performance of the Libbey-Owens-Ford (liquid) solar collector  

NASA Technical Reports Server (NTRS)

Thermal performance tests were conducted on the Libbey-Owens-Ford liquid collector, following long term exposure to natural weathering conditions. Visual inspection of the collector, prior to the retest, indicated noticeable clouding of the inner cover glass, probably resulting from outgassing of the insulation. The absorber plate also showed some discoloration. The test results indicated that performance degradation had occurred at inlet temperatures significantly above ambient. The change in the slope of the efficiency curve, from the original data, is a direct indicator of an increase in the collector heat loss coefficient.

1979-01-01

187

LONG-TERM OPTICAL CONTINUUM COLOR VARIABILITY OF NEARBY ACTIVE GALACTIC NUCLEI  

SciTech Connect

We examine whether the spectral energy distribution of optical continuum emission of active galactic nuclei (AGNs) changes during flux variation, based on accurate and frequent monitoring observations of 11 nearby Seyfert galaxies and QSOs carried out in the B, V, and I bands for seven years by the MAGNUM telescope. The multi-epoch flux data in any two different bands obtained on the same night show a very tight linear flux-to-flux relationship for all target AGNs. The flux of the host galaxy within the photometric aperture is carefully estimated by surface brightness fitting to available high-resolution Hubble Space Telescope images and MAGNUM images. The flux of narrow emission lines in the photometric bands is also estimated from available spectroscopic data. We find that the non-variable component of the host galaxy plus narrow emission lines for all target AGNs is located on the fainter extension of the linear regression line of multi-epoch flux data in the flux-to-flux diagram. This result strongly indicates that the spectral shape of AGN continuum emission in the optical region ({approx}4400-7900 A) does not systematically change during flux variation. The trend of spectral hardening that optical continuum emission becomes bluer as it becomes brighter, which has been reported by many studies, is therefore interpreted as the domination of the variable component of the nearly constant spectral shape of an AGN as it brightens over the non-variable component of the host galaxy plus narrow lines, which is usually redder than AGN continuum emission.

Sakata, Yu; Minezaki, Takeo; Yoshii, Yuzuru; Uchimoto, Yuka Katsuno; Sugawara, Shota [Institute of Astronomy, School of Science, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Kobayashi, Yukiyasu [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Koshida, Shintaro [Department of Astronomy, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0013 (Japan); Aoki, Tsutomu; Tomita, Hiroyuki [Kiso Observatory, Institute of Astronomy, School of Science, University of Tokyo, 10762-30 Mitake, Kiso, Nagano 397-0101 (Japan); Enya, Keigo; Suganuma, Masahiro, E-mail: yusakata@ioa.s.u-tokyo.ac.j [Institute of Space and Astronomical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan)

2010-03-01

188

Long-Term Optical Continuum Color Variability of Nearby Active Galactic Nuclei  

NASA Astrophysics Data System (ADS)

We examine whether the spectral energy distribution of optical continuum emission of active galactic nuclei (AGNs) changes during flux variation, based on accurate and frequent monitoring observations of 11 nearby Seyfert galaxies and QSOs carried out in the B, V, and I bands for seven years by the MAGNUM telescope. The multi-epoch flux data in any two different bands obtained on the same night show a very tight linear flux-to-flux relationship for all target AGNs. The flux of the host galaxy within the photometric aperture is carefully estimated by surface brightness fitting to available high-resolution Hubble Space Telescope images and MAGNUM images. The flux of narrow emission lines in the photometric bands is also estimated from available spectroscopic data. We find that the non-variable component of the host galaxy plus narrow emission lines for all target AGNs is located on the fainter extension of the linear regression line of multi-epoch flux data in the flux-to-flux diagram. This result strongly indicates that the spectral shape of AGN continuum emission in the optical region (~4400-7900 Å) does not systematically change during flux variation. The trend of spectral hardening that optical continuum emission becomes bluer as it becomes brighter, which has been reported by many studies, is therefore interpreted as the domination of the variable component of the nearly constant spectral shape of an AGN as it brightens over the non-variable component of the host galaxy plus narrow lines, which is usually redder than AGN continuum emission.

Sakata, Yu; Minezaki, Takeo; Yoshii, Yuzuru; Kobayashi, Yukiyasu; Koshida, Shintaro; Aoki, Tsutomu; Enya, Keigo; Tomita, Hiroyuki; Suganuma, Masahiro; Katsuno Uchimoto, Yuka; Sugawara, Shota

2010-03-01

189

Persistent long-term facilitation at an identified synapse becomes labile with activation of short-term heterosynaptic plasticity.  

PubMed

Short-term and long-term synaptic plasticity are cellular correlates of learning and memory of different durations. Little is known, however, how these two forms of plasticity interact at the same synaptic connection. We examined the reciprocal impact of short-term heterosynaptic or homosynaptic plasticity at sensorimotor synapses of Aplysia in cell culture when expressing persistent long-term facilitation (P-LTF) evoked by serotonin [5-hydroxytryptamine (5-HT)]. Short-term heterosynaptic plasticity induced by 5-HT (facilitation) or the neuropeptide FMRFa (depression) and short-term homosynaptic plasticity induced by tetanus [post-tetanic potentiation (PTP)] or low-frequency stimulation [homosynaptic depression (HSD)] of the sensory neuron were expressed in both control synapses and synapses expressing P-LTF in the absence or presence of protein synthesis inhibitors. All forms of short-term plasticity failed to significantly affect ongoing P-LTF in the absence of protein synthesis inhibitors. However, P-LTF reversed to control levels when either 5-HT or FMRFa was applied in the presence of rapamycin. In contrast, P-LTF was unaffected when either PTP or HSD was evoked in the presence of either rapamycin or anisomycin. These results indicate that synapses expressing persistent plasticity acquire a "new" baseline and functionally express short-term changes as naive synapses, but the new baseline becomes labile following selective activations-heterosynaptic stimuli that evoke opposite forms of plasticity-such that when presented in the presence of protein synthesis inhibitors produce a rapid reversal of the persistent plasticity. Activity-selective induction of a labile state at synapses expressing persistent plasticity may facilitate the development of therapies for reversing inappropriate memories. PMID:24695698

Hu, Jiang-Yuan; Schacher, Samuel

2014-04-01

190

Brain activation patterns in major depressive disorder and work stress-related long-term sick leave among Swedish females.  

PubMed

Deficits in executive functioning and working memory associated with frontal lobe dysfunction are prominent in depression and work-related long-term sick leave (LTSL). This study used functional magnetic resonance imaging (fMRI) to investigate potential differences in brain activation patterns in these conditions. In addition, the function of the hypothalamic-pituitary-adrenal (HPA) axis was examined and compared between groups. Since there is a clear overrepresentation of women in these diagnostic groups, and to ensure a more homogenous sample population, only women were included. To examine the neural correlates of relevant cognitive processes in patients on sick leave >90 days due to work-related LTSL, recently diagnosed patients with major depression Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV criteria, untreated), and healthy controls (n = 10, each group), a 2-back working memory task and a visual long-term memory task were administered during fMRI scanning. HPA axis functioning was investigated using a diurnal curve of saliva cortisol and a dexamethasone suppression test. Task performance was comparable among the three groups. Multivariate image analysis revealed that both memory tasks engaged a similar brain network in all three groups, including the prefrontal and parietal cortex. During the 2-back task, LTSL patients had significant frontal hypoactivation compared to controls and patients with depression. Saliva cortisol measurements showed a flattening of the diurnal rythmicity in LTSL patients compared to patients with depression and healthy contols. Taken together, these findings indicate that work stress-related LTSL and major depression are dissociable in terms of frontal activation and diurnal cortisol rhythmicity. PMID:22217254

Sandström, Agneta; Säll, Roland; Peterson, Jonas; Salami, Alireza; Larsson, Anne; Olsson, Tommy; Nyberg, Lars

2012-09-01

191

Long-term activity-induced changes in the brain : a study of translational regulation and structural plasticity  

E-print Network

Long-lasting changes must take place in the brain to store the skills and memories that have been learned by the organism throughout its history. Long-term memory (LTM), and its cellular correlate, the late-phase of long-term ...

Govindarajan, Arvind

2005-01-01

192

Long-term and baseline recreational physical activity and risk of endometrial cancer: the California Teachers Study  

PubMed Central

Background: Physical activity may be associated with decreasing endometrial cancer risk; it remains unclear whether the association is modified by body size. Methods: Among 93?888 eligible California Teachers Study participants, 976 were diagnosed with incident endometrial cancer between 1995–1996 and 2007. Cox proportional hazards regression methods were used to estimate relative risks (RRs) and 95% confidence intervals (CIs) for endometrial cancer associated with long-term (high school through age 54 years) and baseline (3 years prior to joining the cohort) strenuous and moderate recreational physical activity, overall and by body size. Results: Increased baseline strenuous recreational physical activity was associated with decreased endometrial cancer risk (Ptrend=0.006) with approximately 25% lower risk among women exercising >3?h per week per year than among those exercising <1/2?h per week per year (RR, 0.76; 95% CI, 0.63–0.92). This inverse association was observed among overweight/obese women (body mass index ?25?kg?m?2; Ptrend=0.006), but not among thinner women (Ptrend=0.12). Baseline moderate activity was associated with lower risk among overweight/obese women. Conclusion: Increasing physical activity, particularly strenuous activity, may be a lifestyle change that overweight and obese women can implement to reduce their endometrial cancer risk. PMID:23860525

Dieli-Conwright, C M; Ma, H; Lacey, J V; Henderson, K D; Neuhausen, S; Horn-Ross, P L; Deapen, D; Sullivan-Halley, J; Bernstein, L

2013-01-01

193

Brain-Derived Neurotrophic Factor Induces Long-Term Potentiation in Intact Adult Hippocampus: Requirement for ERK Activation Coupled to CREB and Upregulation of Arc Synthesis  

Microsoft Academic Search

Brain-derived neurotrophic factor (BDNF) is implicated in long- term synaptic plasticity in the adult hippocampus, but the cellular mechanisms are little understood. Here we used intra- hippocampal microinfusion of BDNF to trigger long-term po- tentiation (BDNF-LTP) at medial perforant path-granule cell synapses in vivo. BDNF infusion led to rapid phosphorylation of the mitogen-activated protein (MAP) kinases ERK (extracellular signal-regulated protein

Shui-Wang Ying; Marie Futter; Kobi Rosenblum; Mark J. Webber; Stephen P. Hunt; Timothy V. P. Bliss

2002-01-01

194

Pain in long-term breast cancer survivors: the role of body mass index, physical activity, and sedentary behavior.  

PubMed

Although pain is common among post-treatment breast cancer survivors, studies that are longitudinal, identify a case definition of clinically meaningful pain, or examine factors contributing to pain in survivors are limited. This study describes longitudinal patterns of pain in long-term breast cancer survivors, evaluating associations of body mass index (BMI), physical activity, sedentary behavior with mean pain severity and above-average pain. Women newly diagnosed with stages 0-IIIA breast cancer (N = 1183) were assessed, on average, 6 months (demographic/clinical characteristics), 30 months (demographics), 40 months (demographics, pain), 5 years (BMI, physical activity, and sedentary behavior), and 10 years (demographics, pain, BMI, physical activity, and sedentary behavior) post-diagnosis. This analysis includes survivors who completed pain assessments 40 months post-diagnosis (N = 801), 10 years post-diagnosis (N = 563), or both (N = 522). Above-average pain was defined by SF-36 bodily pain scores ?1/2 standard deviation worse than age-specific population norms. We used multiple regression models to test unique associations of BMI, physical activity, and sedentary behavior with pain adjusting for demographic and clinical factors. The proportion of survivors reporting above-average pain was higher at 10 years than at 40 months (32.3 vs. 27.8 %, p < 0.05). Approximately one-quarter of survivors reported improved pain, while 9.0 % maintained above-average pain and 33.1 % reported worsened pain. Cross-sectionally at 10 years, overweight and obese survivors reported higher pain than normal-weight survivors and women meeting physical activity guidelines were less likely to report above-average pain than survivors not meeting these guidelines (p < 0.05). Longitudinally, weight gain (>5 %) was positively associated, while meeting physical activity guidelines was inversely associated, with above-average pain (OR, 95 % CI = 1.76, 1.03-3.01 and 0.40, 0.20-0.84, respectively) (p < 0.05). Weight gain and lack of physical activity place breast cancer survivors at risk for pain long after treatment ends. Weight control and exercise interventions should be tested for effects on long-term pain in these women. PMID:23242613

Forsythe, Laura P; Alfano, Catherine M; George, Stephanie M; McTiernan, Anne; Baumgartner, Kathy B; Bernstein, Leslie; Ballard-Barbash, Rachel

2013-01-01

195

Pain in long-term breast cancer survivors: The role of body mass index, physical activity, and sedentary behavior  

PubMed Central

Although pain is common among post-treatment breast cancer survivors, studies that are longitudinal, identify a case definition of clinically meaningful pain, or examine factors contributing to pain in survivors are limited. This study describes longitudinal patterns of pain in long-term breast cancer survivors, evaluating associations of body mass index [BMI], physical activity, sedentary behavior with mean pain severity and above-average pain. Women newly diagnosed with stages 0–IIIA breast cancer (N=1183) were assessed, on average, 6 months (demographic/clinical characteristics), 30 months (demographics), 40 months (demographics, pain), 5 years (BMI, physical activity, and sedentary behavior) and 10 years (demographics, pain, BMI, physical activity, and sedentary behavior) post-diagnosis. This analysis includes survivors who completed pain assessments 40 months post-diagnosis (N=801), 10 years post-diagnosis (N=563), or both (N=522). Above-average pain was defined by SF-36 bodily pain scores ?1/2 standard deviation worse than age-specific population norms. We used multiple regression models to test unique associations of BMI, physical activity, and sedentary behavior with pain adjusting for demographic and clinical factors. The proportion of survivors reporting above-average pain was higher at 10 years than at 40 months (32.3% vs. 27.8%, p<0.05). Approximately one-quarter of survivors reported improved pain, while 9.0% maintained above-average pain and 33.1% reported worsened pain. Cross-sectionally at 10 years, overweight and obese survivors reported higher pain than normal-weight survivors and women meeting physical activity guidelines were less likely to report above-average pain than survivors not meeting these guidelines (p<0.05). Longitudinally, weight gain (>5%) was positively associated, while meeting physical activity guidelines was inversely associated, with above-average pain (OR, 95% CI= 1.76, 1.03–3.01 and 0.40 (0.20–0.84, respectively) (p<0.05). Weight gain and lack of physical activity place breast cancer survivors at risk for pain long after treatment ends. Weight control and exercise interventions should be tested for effects on long-term pain in these women. PMID:23242613

Forsythe, Laura P; Alfano, Catherine M; George, Stephanie M; McTiernan, Anne; Baumgartner, Kathy B; Bernstein, Leslie; Ballard-Barbash, Rachel

2014-01-01

196

Long-term effects of fertilizer on soil enzymatic activity of wheat field soil in Loess Plateau, China.  

PubMed

The effects of long-term (29 years) fertilization on local agro-ecosystems in the Loess Plateau of northwest China, containing a single or combinations of inorganic (Nitrogen, N; Phosphate, P) and organic (Mature, M Straw, S) fertilizer, including N, NP, SNP, M, MNP, and a control. The soil enzymes, including dehydrogenase, urease, alkaline phosphatase, invertase and glomalin, were investigated in three physiological stages (Jointing, Dough, and Maturity) of wheat growth at three depths of the soil profile (0-15, 16-30, 31-45 cm). We found that the application of farmyard manure and straw produced the highest values of soil enzymatic activity, especially a balanced applied treatment of MNP. Enzymatic activity was lowest in the control. Values were generally highest at dough, followed by the jointing and maturity stages, and declined with soil profile depth. The activities of the enzymes investigated here are significantly correlated with each other and are correlated with soil nutrients, in particular with soil organic carbon. Our results suggest that a balanced application of fertilizer nutrients and organic manure (especially those containing P) has positive effects on multiple soil chemical parameters, which in turn enhances enzyme activity. We emphasize the role of organic manure in maintaining soil organic matter and promoting biological activity, as its application can result in a substantial increase in agricultural production and can be sustainable for many years. PMID:25134679

Hu, Weigang; Jiao, Zhifang; Wu, Fasi; Liu, Yongjun; Dong, Maoxing; Ma, Xiaojun; Fan, Tinglu; An, Lizhe; Feng, Huyuan

2014-12-01

197

Phorbol 12-Myristate 13-Acetate Enhances Long-Term Potentiation in the Hippocampus through Activation of Protein Kinase C? and ?.  

PubMed

Many intracellular proteins and signaling cascades contribute to the sensitivity of N-methyl-D-aspartate receptors (NMDARs). One such putative contributor is the serine/threonine kinase, protein kinase C (PKC). Activation of PKC by phorbol 12-myristate 13-acetate (PMA) causes activation of extracellular signal-regulated kinase (ERK) and promotes the formation of new spines in cultured hippocampal neurons. The purpose of this study was to examine which PKC isoforms are responsible for the PMA-induced augmentation of long-term potentiation (LTP) in the CA1 stratum radiatum of the hippocampus in vitro and verify that this facilitation requires NMDAR activation. We found that PMA enhanced the induction of LTP by a single episode of theta-burst stimulation in a concentration-dependent manner without affecting to magnitude of baseline field excitatory postsynaptic potentials. Facilitation of LTP by PMA (200 nM) was blocked by the nonspecific PKC inhibitor, Ro 31-8220 (10µM); the selective PKC? inhibitor, rottlerin (1µM); and the PKC? inhibitor, TAT-?V1-2 peptide (500 nM). Moreover, the NMDAR blocker DL-APV (50µM) prevented enhancement of LTP by PMA. Our results suggest that PMA contributes to synaptic plasticity in the nervous system via activation of PKC? and/or PKC?, and confirm that NMDAR activity is required for this effect. PMID:23440225

Kim, Eung Chang; Lee, Myeong Jong; Shin, Sang Yep; Seol, Geun Hee; Han, Seung Ho; Yee, Jaeyong; Kim, Chan; Min, Sun Seek

2013-02-01

198

Multi-decade Measurements of the Long-Term Trends of Atmospheric Species by High-Spectral-Resolution Infrared Solar Absorption Spectroscopy  

NASA Technical Reports Server (NTRS)

Solar absorption spectra were recorded for the first time in 5 years with the McMath Fourier transform spectrometer at the US National solar Observatory on Kitt Peak in southern Arizona, USA (31.91 N latitude, 111.61 W longitude, 2.09 km altitude). The solar absorption spectra cover 750-1300 and 1850-5000 cm(sup -1) and were recorded on 20 days during March-June 2009. The measurements mark the continuation of a long-term record of atmospheric chemical composition measurements that have been used to quantify seasonal cycles and long-term trends of both tropospheric and stratospheric species from observations that began i 1977. Fits to the measured spectra have been performed, and they indicate the spectra obtained since return to operational status are nearly free of channeling and the instrument line shape function is well reproduced taking into account the measurement parameters. We report updated time series measurements of total columns for six atmospheric species and their analysis for seasonal cycles and long-term trends. An sn example, the time series fit shows a decrease in the annual increase rate i Montreal-Protocol-regulated chlorofluorocarbon CCL2F2 from 1.51 plus or minus 0.38% yr(sup -1) at the beginning of the time span to -1.54 plus or minus 1.28 yr(sup -1) at the end of the time span, 1 sigma, and hence provides evidence for the impact of those regulations on the trend.

Rinsland, Curtis P.; Chiou, Linda; Goldman, Aaron; Hannigan, James W.

2010-01-01

199

An exploration of the effectiveness of artificial mini-magnetospheres as a potential Solar Storm shelter for long term human space missions  

E-print Network

In this paper we explore the effectiveness of an artificial mini-magnetosphere as a potential radiation shelter for long term human space missions. Our study includes the differences that the plasma environment makes to the efficiency of the shielding from the high energy charged particle component of solar and cosmic rays, which radically alters the power requirements. The incoming electrostatic charges are shielded by fields supported by the self captured environmental plasma of the solar wind, potentially augmented with additional density. The artificial magnetic field generated on board acts as the means of confinement and control. Evidence for similar behaviour of electromagnetic fields and ionised particles in interplanetary space can be gained by the example of the enhanced shielding effectiveness of naturally occurring "mini-magnetospheres" on the moon. The shielding effect of surface magnetic fields of the order of ~100s nanoTesla is sufficient to provide effective shielding from solar proton bombard...

Bamford, Ruth; Bradford, John; Todd, Tom N; Stafford-Allen, Robin; Alves, E Paulo; Silva, Luis; Collingwood, Cheryl; Crawford, Ian A; Bingham, Robert

2014-01-01

200

Postsynaptic activity reverses the sign of the acetylcholine-induced long-term plasticity of GABAA inhibition.  

PubMed

Acetylcholine (ACh) regulates forms of plasticity that control cognitive functions but the underlying mechanisms remain largely unknown. ACh controls the intrinsic excitability, as well as the synaptic excitation and inhibition of CA1 hippocampal pyramidal cells (PCs), cells known to participate in circuits involved in cognition and spatial navigation. However, how ACh regulates inhibition in function of postsynaptic activity has not been well studied. Here we show that in rat PCs, a brief pulse of ACh or a brief stimulation of cholinergic septal fibers combined with repeated depolarization induces strong long-term enhancement of GABAA inhibition (GABAA-LTP). Indeed, this enhanced inhibition is due to the increased activation of ?5??2 subunit-containing GABAA receptors by the GABA released. GABAA-LTP requires the activation of M1-muscarinic receptors and an increase in cytosolic Ca(2+). In the absence of PC depolarization ACh triggered a presynaptic depolarization-induced suppression of inhibition (DSI), revealing that postsynaptic activity gates the effects of ACh from presynaptic DSI to postsynaptic LTP. These results provide key insights into mechanisms potentially linked with cognitive functions, spatial navigation, and the homeostatic control of abnormal hyperexcitable states. PMID:24938789

Domínguez, Soledad; Fernández de Sevilla, David; Buño, Washington

2014-07-01

201

Postsynaptic activity reverses the sign of the acetylcholine-induced long-term plasticity of GABAA inhibition  

PubMed Central

Acetylcholine (ACh) regulates forms of plasticity that control cognitive functions but the underlying mechanisms remain largely unknown. ACh controls the intrinsic excitability, as well as the synaptic excitation and inhibition of CA1 hippocampal pyramidal cells (PCs), cells known to participate in circuits involved in cognition and spatial navigation. However, how ACh regulates inhibition in function of postsynaptic activity has not been well studied. Here we show that in rat PCs, a brief pulse of ACh or a brief stimulation of cholinergic septal fibers combined with repeated depolarization induces strong long-term enhancement of GABAA inhibition (GABAA-LTP). Indeed, this enhanced inhibition is due to the increased activation of ?5??2 subunit-containing GABAA receptors by the GABA released. GABAA-LTP requires the activation of M1-muscarinic receptors and an increase in cytosolic Ca2+. In the absence of PC depolarization ACh triggered a presynaptic depolarization-induced suppression of inhibition (DSI), revealing that postsynaptic activity gates the effects of ACh from presynaptic DSI to postsynaptic LTP. These results provide key insights into mechanisms potentially linked with cognitive functions, spatial navigation, and the homeostatic control of abnormal hyperexcitable states. PMID:24938789

Domínguez, Soledad; Fernández de Sevilla, David; Buño, Washington

2014-01-01

202

Evidence for human fronto-central gamma activity during long-term memory encoding of word sequences.  

PubMed

Although human gamma activity (30-80 Hz) associated with visual processing is often reported, it is not clear to what extend gamma activity can be reliably detected non-invasively from frontal areas during complex cognitive tasks such as long term memory (LTM) formation. We conducted a memory experiment composed of 35 blocks each having three parts: LTM encoding, working memory (WM) maintenance and LTM retrieval. In the LTM encoding and WM maintenance parts, participants had to respectively encode or maintain the order of three sequentially presented words. During LTM retrieval subjects had to reproduce these sequences. Using magnetoencephalography (MEG) we identified significant differences in the gamma and beta activity. Robust gamma activity (55-65 Hz) in left BA6 (supplementary motor area (SMA)/pre-SMA) was stronger during LTM rehearsal than during WM maintenance. The gamma activity was sustained throughout the 3.4 s rehearsal period during which a fixation cross was presented. Importantly, the difference in gamma band activity correlated with memory performance over subjects. Further we observed a weak gamma power difference in left BA6 during the first half of the LTM rehearsal interval larger for successfully than unsuccessfully reproduced word triplets. In the beta band, we found a power decrease in left anterior regions during LTM rehearsal compared to WM maintenance. Also this suppression of beta power correlated with memory performance over subjects. Our findings show that an extended network of brain areas, characterized by oscillatory activity in different frequency bands, supports the encoding of word sequences in LTM. Gamma band activity in BA6 possibly reflects memory processes associated with language and timing, and suppression of beta activity at left frontal sensors is likely to reflect the release of inhibition directly associated with the engagement of language functions. PMID:21738641

Meeuwissen, Esther Berendina; Takashima, Atsuko; Fernández, Guillén; Jensen, Ole

2011-01-01

203

Membrane-associated glucocorticoid activity is necessary for modulation of long-term memory via chromatin modification.  

PubMed

Glucocorticoid hormones enhance the consolidation of long-term memory of emotionally arousing training experiences. This memory enhancement requires activation of the cAMP-dependent kinase pathway and the subsequent phosphorylation of cAMP response-element binding (CREB) protein. Here, we demonstrate that glucocorticoids enhance the consolidation of hippocampus-dependent and hippocampus-independent aspects of object recognition memory via chromatin modification. More specifically, systemic corticosterone increases histone acetylation, a form of chromatin modification, in both the hippocampus and insular cortex following training on an object recognition task. This led us to examine whether increasing histone acetylation via histone deacetylase (HDAC) inhibition enhances memory in a manner similar to corticosterone. We found a double dissociation between posttraining HDAC inhibitor infusion into the insular cortex and hippocampus on the enhancement of object recognition and object location memory, respectively. In determining the molecular pathway upstream of glucocorticoids' effects on chromatin modification, we found that activation of membrane-associated glucocorticoid receptors (GRs) and the subsequent interaction between phospho-CREB and CREB-binding protein (CBP) appear to be necessary for glucocorticoids to enhance memory consolidation via chromatin modification. In contrast, mineralocorticoid receptors (MRs) do not appear to be involved. The findings also indicate that glucocorticoid activity has differential influences on hippocampus-dependent and hippocampus-independent components of memory for objects. PMID:20371824

Roozendaal, Benno; Hernandez, Angelina; Cabrera, Sara M; Hagewoud, Roelina; Malvaez, Melissa; Stefanko, Daniel P; Haettig, Jakob; Wood, Marcelo A

2010-04-01

204

Long-term investigations of radiocaesium activity concentrations in carps in north Croatia after the Chernobyl accident  

E-print Network

Long-term investigations of radiocaesium activity concentrations in carps in the Republic of Croatia are presented. The radiocaesium levels in carps decreased exponentially and the effective ecological half-life of 137Cs in carps was estimated to be about 1 year for 1987-2002 period and 5 years for 1993-2005 period. The observed 134Cs:137Cs activity ratio in carps has been found to be similar to the ratio that has been observed in other environmental samples. Concentration factor for carps (wet weight) was roughly estimated to be 128 +/- 74 Lkg-1, which is in reasonable agreement with model prediction based on K+ concentrations in water. Estimated annual effective doses received by 134Cs and 137Cs intake due to consumption of carps for an adult member of Croatian population are small, per caput dose for the 1987 - 2005 estimated to be 0.5 +/- 0.2 microSv. Due to minor freshwater fish consumption in Croatia and low radiocaesium activity concentrations in carps, it can be concluded that carps consumption was no...

Franic, Z

2007-01-01

205

Using smartphones to collect time-activity data for long-term personal-level air pollution exposure assessment.  

PubMed

Because of the spatiotemporal variability of people and air pollutants within cities, it is important to account for a person's movements over time when estimating personal air pollution exposure. This study aimed to examine the feasibility of using smartphones to collect personal-level time-activity data. Using Skyhook Wireless's hybrid geolocation module, we developed "Apolux" (Air, Pollution, Exposure), an Android(TM) smartphone application designed to track participants' location in 5-min intervals for 3 months. From 42 participants, we compared Apolux data with contemporaneous data from two self-reported, 24-h time-activity diaries. About three-fourths of measurements were collected within 5?min of each other (mean=74.14%), and 79% of participants reporting constantly powered-on smartphones (n=38) had a daily average data collection frequency of <10?min. Apolux's degree of temporal resolution varied across manufacturers, mobile networks, and the time of day that data collection occurred. The discrepancy between diary points and corresponding Apolux data was 342.3?m (Euclidian distance) and varied across mobile networks. This study's high compliance and feasibility for data collection demonstrates the potential for integrating smartphone-based time-activity data into long-term and large-scale air pollution exposure studies.Journal of Exposure Science and Environmental Epidemiology advance online publication, 26 November 2014; doi:10.1038/jes.2014.78. PMID:25425137

Glasgow, Mark L; Rudra, Carole B; Yoo, Eun-Hye; Demirbas, Murat; Merriman, Joel; Nayak, Pramod; Crabtree-Ide, Christina; Szpiro, Adam A; Rudra, Atri; Wactawski-Wende, Jean; Mu, Lina

2014-11-26

206

X-ray, FUV, and UV Observations of ? Centauri B: Determination of Long-term Magnetic Activity Cycle and Rotation Period  

NASA Astrophysics Data System (ADS)

Over the last couple of decades we have been carrying out a study of stellar magnetic activity, dynamos, atmospheric physics, and spectral irradiances from a sample of solar-type G0-5 V stars with different ages. One of the major goals of this program is to study the evolution of the Sun's X-ray through NUV spectral irradiances with age. Of particular interest is the determination of the young Sun's elevated levels of high-energy fluxes because of the critical roles that X-ray (coronal) through FUV (transition region (TR), chromospheric) emissions play on the photochemical and photoionization evolution (and possible erosion) of early, young planetary atmospheres and ionospheres. Motivated by the current exoplanetary search missions (such as Kepler and CoRoT, along with the planned Space Interferometry Mission and Darwin/Terrestrial Planet Finder missions) that are hunting for Earth-size planets in the habitable zones (liquid water) of nearby main-sequence G-M stars, we are expanding our program to cooler, less luminous, but very importantly, much more numerous main-sequence K-type stars, such as ? Centauri B. The long life (2-3× longer than the Sun) and slow evolution of K stars provide nearly constant energy sources for possible hosted planets. This program parallels our "Sun in Time" program, but extends the study to stars with deeper convective zone depths. Presented here are X-ray (coronal; ROSAT, Chandra, XMM-Newton), UV (TR; International Ultraviolet Explorer (IUE)), NUV (chromospheric; IUE), and recently acquired FUV (TR/chromospheric; FUSE Cycles 7/8) observations of the K1 V star ? Cen B (HD 128621; V = 1.33; (B - V) = +0.88; ? = 5.6 ± 0.6 Gyr). These combined high-energy measures provide a more complete look into the nature of ? Cen B's magnetic activity and X-ray-UV radiances. We find that ? Cen B has exhibited significant long-term variability in X-ray through NUV emission fluxes, indicating a solar-like long-term activity cycle of P cycle = 8.84 ± 0.4 years. In addition, analysis of the short-term rotational modulation of mean light due to the effects of magnetically active regions has yielded a well-determined rotation period of P rotation = 36.2 ± 1.4 days. ? Cen B is the only old main-sequence K star with a reliably determined age and rotation period, and for early K stars, as in the case of the Sun for G2 V stars, is an important calibrator for stellar age/rotation/activity relations.

DeWarf, L. E.; Datin, K. M.; Guinan, E. F.

2010-10-01

207

Indoor test and long-term weathering effects on the thermal performance of the solar energy system (liquid) solar collector. [Marshall Space Flight Center solar test facility and solar simulator  

NASA Technical Reports Server (NTRS)

The procedures used and the results obtained during the evaluation test program on a liquid solar collector are presented. The narrow flat plate collector with reflective concentrating mirrors uses water as the working fluid. The double-covered collector weighs 137 pounds and has overall dimensions of about 35" by 77" by 6.75". The test program was conducted to obtain the following information: thermal performance data under simulated conditions, structural behavior under static load, and the effects of long term exposure to natural weathering.

1979-01-01

208

Muscarinic acetylcholine receptor activation blocks long-term potentiation at cerebellar parallel fiber–Purkinje cell synapses via cannabinoid signaling  

PubMed Central

Muscarinic acetylcholine receptors (mAChRs) are known to modulate synaptic plasticity in various brain areas. A signaling pathway triggered by mAChR activation is the production and release of endocannabinoids that bind to type 1 cannabinoid receptors (CB1R) located on synaptic terminals. Using whole-cell patch-clamp recordings from rat cerebellar slices, we have demonstrated that the muscarinic agonist oxotremorine-m (oxo-m) blocks the induction of presynaptic long-term potentiation (LTP) at parallel fiber (PF)–Purkinje cell synapses in a CB1R-dependent manner. Under control conditions, LTP was induced by delivering 120 PF stimuli at 8 Hz. In contrast, no LTP was observed when oxo-m was present during tetanization. PF-LTP was restored when the CB1R antagonist N-1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-1-piperidinyl-1H-pyrazole-3-carboxamide (AM251) was coapplied with oxo-m. Furthermore, the suppressive effect of oxo-m on PF-LTP was abrogated by the GDP analog GDP-?-S (applied intracellularly), the phospholipase C inhibitor U-73122, and the diacylglycerol lipase inhibitor tetrahydrolipstatin (THL), suggesting that cannabinoid synthesis results from the activation of Gq-coupled mAChRs present on Purkinje cells. The oxo-m–mediated suppression of LTP was also prevented in the presence of the M3 receptor antagonist DAU 5884, and was absent in M1/M3 receptor double-KO mice, identifying M3 receptors as primary oxo-m targets. Our findings allow for the possibility that cholinergic signaling in the cerebellum—which may result from long-term depression (LTD)-related disinhibition of cholinergic neurons in the vestibular nuclei—suppresses presynaptic LTP to prevent an up-regulation of transmitter release that opposes the reduction of postsynaptic responsiveness. This modulatory capacity of mAChR signaling could promote the functional penetrance of LTD. PMID:23776234

Rinaldo, Lorenzo; Hansel, Christian

2013-01-01

209

Long-Term Effects of Ammonia on the Behavioral Activity of the Aquatic Snail Potamopyrgus antipodarum (Hydrobiidae, Mollusca)  

Microsoft Academic Search

An appropriate approach to assess the effect of toxicants on aquatic animals is to monitor behavioral endpoints, as they are\\u000a a link between physiological and ecological processes. A group that can be exposed long-term to low toxic concentrations is\\u000a benthic macroinvertebrates, as their mobility in aquatic ecosystems is relatively limited. Therefore, the study of behavioral\\u000a long-term effects in this group

Álvaro Alonso; Julio A. Camargo

2009-01-01

210

Midazolam inhibits hippocampal long-term potentiation and learning through dual central and peripheral benzodiazepine receptor activation and neurosteroidogenesis  

PubMed Central

Benzodiazepines (BDZs) enhance ?-aminobutyric acid-A (GABAA) receptor inhibition by direct actions on central BDZ receptors (CBRs). Although some BDZs also bind mitochondrial receptors (translocator protein 18kDa, TSPO) and promote the synthesis of GABA-enhancing neurosteroids, the role of neurosteroids in the clinical effects of BDZs is unknown. In rat hippocampal slices, we compared midazolam, an anesthetic BDZ with clonazepam, an anticonvulsant/anxiolytic BDZ that activates CBRs selectively. Midazolam, but not clonazepam, increased neurosteroid levels in CA1 pyramidal neurons without changing TSPO immunostaining. Midazolam, but not clonazepam, also augmented a form of spike inhibition following stimulation adjacent to the pyramidal cell layer and inhibited induction of long-term potentiation. These effects were prevented by finasteride, an inhibitor of neurosteroid synthesis, or 17PA (17-phenyl-(3?, 5?)-androst-16-en-3-ol), a blocker of neurosteroid effects on GABAA receptors. Moreover, the synaptic effects were mimicked by a combination of clonazepam with FGIN, a selective TSPO agonist, or a combination of clonazepam with exogenous allopregnanolone. Consistent with these in vitro results, finasteride abolished the effects of midazolam on contextual fear learning when administrated one day prior to midazolam injection. Thus, dual activation of CBRs and TSPO appears to result in unique actions of clinically-important BDZs. Furthermore, endogenous neurosteroids are shown to be important regulators of pyramidal neuron function and synaptic plasticity. PMID:21159950

Tokuda, Kazuhiro; O’Dell, Kazuko A.; Izumi, Yukitoshi; Zorumski, Charles F.

2010-01-01

211

Dynamics of nascent and active zone ultrastructure as synapses enlarge during long-term potentiation in mature hippocampus.  

PubMed

Nascent zones and active zones are adjacent synaptic regions that share a postsynaptic density, but nascent zones lack the presynaptic vesicles found at active zones. Here dendritic spine synapses were reconstructed through serial section electron microscopy (3DEM) and EM tomography to investigate nascent zone dynamics during long-term potentiation (LTP) in mature rat hippocampus. LTP was induced with theta-burst stimulation, and comparisons were made with control stimulation in the same hippocampal slices at 5 minutes, 30 minutes, and 2 hours post-induction and to perfusion-fixed hippocampus in vivo. Nascent zones were present at the edges of ?35% of synapses in perfusion-fixed hippocampus and as many as ?50% of synapses in some hippocampal slice conditions. By 5 minutes, small dense-core vesicles known to transport active zone proteins moved into more presynaptic boutons. By 30 minutes, nascent zone area decreased, without significant change in synapse area, suggesting that presynaptic vesicles were recruited to preexisting nascent zones. By 2 hours, both nascent and active zones were enlarged. Immunogold labeling revealed glutamate receptors in nascent zones; however, average distances from nascent zones to docked presynaptic vesicles ranged from 170?±?5 nm in perfusion-fixed hippocampus to 251?±?4 nm at enlarged synapses by 2 hours during LTP. Prior stochastic modeling suggests that decrease in glutamate concentration reduces the probability of glutamate receptor activation from 0.4 at the center of release to 0.1 just 200 nm away. Thus, conversion of nascent zones to functional active zones likely requires the recruitment of presynaptic vesicles during LTP. PMID:25043676

Bell, Maria Elizabeth; Bourne, Jennifer N; Chirillo, Michael A; Mendenhall, John M; Kuwajima, Masaaki; Harris, Kristen M

2014-12-01

212

Short-lived tectonic switch mechanism for long-term pulses of volcanic activity after mega-thrust earthquakes  

NASA Astrophysics Data System (ADS)

Eruptive rates in volcanic arcs increase significantly after mega-thrust earthquakes in subduction zones. Over short to intermediate time periods the link between mega-thrust earthquakes and arc response can be attributed to dynamic triggering processes or static stress changes, but a fundamental mechanism that controls long-term pulses of volcanic activity after mega-thrust earthquakes has not been proposed yet. Using geomechanical, geological, and geophysical arguments, we propose that increased eruption rates over longer timescales are due to the relaxation of the compressional regime that accompanies mega-thrust subduction zone earthquakes. More specifically, the reduction of the horizontal stress ?h promotes the occurrence of short-lived strike-slip kinematics rather than reverse faulting in the volcanic arc. The relaxation of the pre-earthquake compressional regime facilitates magma mobilization by providing a short-circuit pathway to shallow depths by significantly increasing the hydraulic properties of the system. The timescale for the onset of strike-slip faulting depends on the degree of shear stress accumulated in the arc during inter-seismic periods, which in turn is connected to the degree of strain-partitioning at convergent margins. We performed Coulomb stress transfer analysis to determine the order of magnitude of the stress perturbations in present-day volcanic arcs in response to five actual mega-thrust earthquakes; the 2005 M8.6, 2007 M8.5, and 2007 M7.9 Sumatra earthquakes; the 2010 M8.8 Maule, Chile earthquake; and the 2011 M9.0 Tohoku, Japan earthquake. We find that all, but one, the shallow earthquakes that occurred in the arcs of Sumatra, Chile and Japan show a marked lateral component. Our hypothesis suggests that the long-term response of volcanic arcs to subduction zone mega-thrust earthquakes will be manifested as predominantly strike-slip seismic events, and that these future earthquakes will be followed closely by seismic swarms, inflation, and other indications of a rising magma source.

Lupi, M.; Miller, S. A.

2013-06-01

213

Short-lived tectonic switch mechanism for long-term pulses of volcanic activity after mega-thrust earthquakes  

NASA Astrophysics Data System (ADS)

Eruptive rates in volcanic arcs increase significantly after subduction mega-thrust earthquakes. Over short to intermediate time periods the link between mega-thrust earthquakes and arc response can be attributed to dynamic triggering processes or static stress changes, but a fundamental mechanism that controls long-term pulses of volcanic activity after mega-thrust earthquakes has not been proposed yet. Using geomechanical, geological, and geophysical arguments, we propose that increased eruption rates over longer timescales are due to the relaxation of the compressional regime that accompanies mega-thrust subduction zone earthquakes. More specifically, the reduction of the horizontal stress ?h promotes the occurrence of short-lived strike-slip kinematics rather than reverse faulting in the volcanic arc. The relaxation of the pre-earthquake compressional regime facilitates magma mobilisation by providing a short-circuit pathway to shallow depths by significantly increasing the hydraulic properties of the system. The timescale for the onset of strike-slip faulting depends on the degree of shear stress accumulated in the arc during inter-seismic periods, which in turn is connected to the degree of strain-partitioning at convergent margins. We performed Coulomb stress transfer analysis to determine the order of magnitude of the stress perturbations in present-day volcanic arcs in response to five recent mega-thrust earthquakes; the 2005 M8.6, 2007 M8.5, and 2007 M7.9 Sumatra earthquakes; the 2010 M8.8 Maule, Chile earthquake; and the 2011 M9.0 Tohoku, Japan earthquake. We find that all but one the shallow earthquakes that occurred in the arcs of Sumatra, Chile and Japan show a marked lateral component. We suggests that the long-term response of volcanic arcs to subduction zone mega-thrust earthquakes will be manifested as predominantly strike-slip seismic events, and that these future earthquakes may be followed closely by indications of rising magma to shallower depths, e.g. surface inflation and seismic swarms.

Lupi, M.; Miller, S. A.

2014-01-01

214

Long-term community dynamics of small landbirds with and without exposure to extensive disturbance from military training activities.  

PubMed

Military training activities are known to impact individual species, yet our understanding of how such activities influence animal communities is limited. In this study, we used long-term data in a case study approach to examine the extent to which the local small landbird community differed between a site in northeast Kansas that experienced intensive disturbance from military training activities (Ft. Riley Military Installation) and a similar, nearby site that experienced minimal human disturbance (Konza Prairie Biological Station). In addition, we characterized how the regional pool of potential colonizers influenced local community dynamics using Breeding Bird Survey data. From 1991 to 2001, most species of small terrestrial landbirds (73%) recorded during breeding surveys were found at both sites and the mean annual richness at Ft. Riley (39.0 +/- 2.86 [SD]) was very similar to that of Konza Prairie (39.4 +/- 2.01). Richness was maintained at relatively constant levels despite compositional changes because colonizations compensated local extinctions at both sites. These dynamics were driven primarily by woodland species that exhibited stochastic losses and gains and were present at a low local and regional abundance. Our results suggest that military training activities may mimic natural disturbances for some species in this area because the small landbird community did not differ markedly between sites with and sites without extensive human disturbance. Although our results suggest that military training is not associated with large changes in the avian community, additional studies are needed to determine if this pattern is found in other ecological communities. PMID:20084512

Rivers, James W; Gipson, Philip S; Althoff, Donald P; Pontius, Jeffrey S

2010-02-01

215

Long-term performance of activated carbon air cathodes with different diffusion layer porosities in microbial fuel cells.  

PubMed

Activated carbon (AC) air-cathodes are inexpensive and useful alternatives to Pt-catalyzed electrodes in microbial fuel cells (MFCs), but information is needed on their long-term stability for oxygen reduction. AC cathodes were constructed with diffusion layers (DLs) with two different porosities (30% and 70%) to evaluate the effects of increased oxygen transfer on power. The 70% DL cathode initially produced a maximum power density of 1214±123 mW/m(2) (cathode projected surface area; 35±4 W/m(3) based on liquid volume), but it decreased by 40% after 1 year to 734±18 mW/m(2). The 30% DL cathode initially produced less power than the 70% DL cathode, but it only decreased by 22% after 1 year (from 1014±2 mW/m(2) to 789±68 mW/m(2)). Electrochemical tests were used to examine the reasons for the degraded performance. Diffusion resistance in the cathode was found to be the primary component of the internal resistance, and it increased over time. Replacing the cathode after 1 year completely restored the original power densities. These results suggest that the degradation in cathode performance was due to clogging of the AC micropores. These findings show that AC is a cost-effective material for oxygen reduction that can still produce ~750 mW/m(2) after 1 year. PMID:21937216

Zhang, Fang; Pant, Deepak; Logan, Bruce E

2011-12-15

216

Reducing long term sickness absence by an activating intervention in adjustment disorders: a cluster randomised controlled design  

PubMed Central

Aims: To compare an innovative activating intervention with "care as usual" (control group) for the guidance of employees on sickness leave because of an adjustment disorder. It was hypothesised that the intervention would be more effective than care as usual in lowering the intensity of symptoms, increasing psychological resources, and decreasing sickness leave duration. Methods: A prospective, cluster randomised controlled trial was carried out with 192 patients on first sickness leave for an adjustment disorder. Symptom intensity, sickness duration, and return to work rates were measured at 3 months and 12 months. Analyses were performed on an intention to treat basis. Results: At 3 months, significantly more patients in the intervention group had returned to work compared with the control group. At 12 months all patients had returned to work, but sickness leave was shorter in the intervention group than in the control group. The recurrence rate was lower in the intervention group. There were no differences between the two study groups with regard to the decrease of symptoms. At baseline, symptom intensity was higher in the patients than in a normal reference population, but decreased over time in a similar manner in both groups to approximately normal levels. Conclusion: The experimental intervention for adjustment disorders was successful in shortening sick leave duration, mainly by decreasing long term absenteeism. PMID:12771395

van der Klink, J J L; Blonk, R; Schene, A; van Dijk, F J H

2003-01-01

217

Long-term effect of the antibiotic cefalexin on methane production during waste activated sludge anaerobic digestion.  

PubMed

Long-term experiments herein were conducted to investigate the effect of cefalexin (CLX) on methane production during waste activated sludge (WAS) anaerobic digestion. CLX exhibited a considerable inhibition in methane production during the initial 25 days while the negative effect attenuated subsequently and methane production recovered depending on CLX doses used (600 and 1000 mg/L). The highest methane yield reached 450 mL at 1000 mg-CLX/L after 157 days of digestion, 63.8% higher than CLX-free one. Stimulated excretion of extracellular polymeric substances (EPS) by CLX served as microbial protecting layers, creating a suitable environment for microbes' growth and fermentation. Further examination via ultraviolet visible (UV-Vis) spectra also verified the elevated slime EPS, LB-EPS and TB-EPS indicated by UV-254 in the presence of CLX. Unlike the commonly accepted adverse effect, this study demonstrated the beneficial role of CLX in methane production, providing new insights into its true environmental impacts. PMID:25105270

Lu, Xueqin; Zhen, Guangyin; Liu, Yuan; Hojo, Toshimasa; Estrada, Adriana Ledezma; Li, Yu-You

2014-10-01

218

Enhanced prolylhydroxylase activity in the posterior annulus fibrosus of canine intervertebral discs following long-term running exercise.  

PubMed

The effect of long-term excercise on the intervertebral disc collagen concentration (hydroxyproline), collagen-synthesizing enzymes (prolyl-4-hydroxylase, PH, and galactosyl-hydroxylysyl glucosyltransferase, GGT) and hydroxypyridinium crosslinks was studied in ten female beagle dogs. The dogs were run on a treadmill for 1 year starting at the age of 15 weeks. The daily running distance was gradually increased to 40km, which distance the dogs ran for the final 15 weeks. Ten untrained dogs from the same breeding colony served as controls. The nucleus pulposus and anterior and posterior halves of the annulus fibrosus of C2-3, T10-12, L4-5 disc segments were analysed. Crosslinks were measured from the anterior annulus fibrosus of the T10-11 disc. Hydroxyproline and hydroxypyridinium concentrations remained similar in both groups. PH and GGT were significantly elevated by running in the posterior annulus fibrosus of the thoracic and lumbar discs and in the lumbar nucleus pulposus. In the thoracic nucleus pulposus GGT was reduced significantly. The results suggest activated collagen metabolism in the posterior annulus fibrosus of the thoracic and lumbar discs as a result of locally increased strains on the spine. PMID:20058463

Puustjärvi, K; Takala, T; Wang, W; Tammi, M; Helminen, H J; Kovanen, V

1993-10-01

219

Long Term Ecological Resources  

NSDL National Science Digital Library

Students analyze data on temperature and precipitation collected from 26 different Long Term Ecological Research sites and compare them with annual net primary productivity. The students then form an ecological rule to explain their results.

Cooper, Scott

220

Short- and long-term determination of the TDRS solar reflectivity parameter using the Goddard trajectory determination system  

NASA Technical Reports Server (NTRS)

Two aspects of the orbit determination of the Tracking and Data Relay Satellite-East (TDRS-E) are considered. The TDRS-E solar reflectivity parameter, as it affects the accuracy of the determination and propagation of the TDRS-E geosynchronous orbit, varies seasonally due to the changing declination of the sun. Orbit solutions are carried out using varying tracking data arc lengths to ascertain the minimum arc length needed for an accurate determination of the TDRS-E orbital elements and the solar reflectivity parameter.

Bobrowsky, M.; Kay, P. Y.; Drew, A. K.; Hoge, S. L.; Cuevas, O. O.

1988-01-01

221

LONG-TERM VARIATIONS OF THE INTEGRAL RADIATION FLUX AND POSSIBLE TEMPERATURE CHANGES IN THE SOLAR CORE  

Microsoft Academic Search

We show that the cyclic 11-year variations observed in the solar integral radiation flux are due to some fundamental global processes which occur deeply in the Sun and which cause the corresponding changes in the radius and effective temperature of the photosphere. The 11-year variations of the \\

I. Abdusamatov

222

Short- and Long-Term Theory-Based Predictors of Physical Activity in Women Who Participated in a Weight-Management Program  

ERIC Educational Resources Information Center

This study analyzed psychosocial predictors of the Theory of Planned Behavior (TPB) and Self-Determination Theory (SDT) and evaluated their associations with short- and long-term moderate plus vigorous physical activity (MVPA) and lifestyle physical activity (PA) outcomes in women who underwent a weight-management program. 221 participants (age…

Wasserkampf, A.; Silva, M. N.; Santos, I. C.; Carraça, E. V.; Meis, J. J. M.; Kremers, S. P. J.; Teixeira, P. J.

2014-01-01

223

A long-term change of the AR/KR/XE fractionation in the solar corpuscular radiation  

NASA Technical Reports Server (NTRS)

Solar noble gases in an ilmenite separate from breccia 79035 (antiquity greater than 1 Ga) were analyzed by closed system stepped etching (CSSE). All five gases show the familiar two-component structure: first solar-wind (SW) gases are released, followed by gases from solar energetic particles (SEP). Element patterns in 79035 are similar to those of 71501 ilmenite. SW-He-Ne were partly lost, but SEP-He-Ne-Ar are retained (nearly) unfractionated. Constant Ar/Kr/Xe ratios indicate that ilmenites contain an unfractionated sample of the heavy SW-SEP noble gases. Ar/Kr/Xe ratios in the solar corpuscular radiation are, however, different from 'solar system' values, whereby the Kr/Xe difference in 79035 is about twice as large as in 71501. We propose that Xe is less fractionated than Kr and Ar, though its first ionization potential (FIP) is higher than the 'cutoff' at approximately 11.5 eV, above which all elements in SEP are usually assumed to be depleted by a roughly constant factor. SW-Ne may be isotopically slightly heavier in the ancient SW trapped by 79035, as proposed earlier. In this work we extend our previous CSSE studies of solar noble gases including Kr and Xe to a lunar sample irradiated at least 1 Ga ago (breccia 79035, ilmenite separate, 42-64 microns). This sample was particularly gently etched in the first steps. Surprisingly, the first three steps, each releasing less than or equal to 0.5% of the total 36-Ar, showed an SEP-like trapped component plus relatively large concentrations of cosmogenic gases. Steps 4ff contain much less cosmogenic and more solar gas with a SW-like isotope pattern. Thus, a very minor easily etchable phase that has completely lost its SW-gases must be responsible for steps 1-3. We will not discuss these steps here and refer to the actual step 4 as the 'initial' etching step.

Wieler, R.; Baur, H.; Signer, P.

1993-01-01

224

Silver Nanoparticles Modified by Gelatin with Extraordinary pH Stability and Long-Term Antibacterial Activity  

PubMed Central

The potential for application of any nanoparticles, including silver nanoparticles (AgNPs), is strongly dependent on their stability against aggregation. Therefore, improvement of this parameter is a key task, especially in the case of AgNPs, because a correlation between size and biological activity has been demonstrated. In the present work, a natural stabilizer, gelatin, was investigated for the stabilization of AgNPs in an aqueous dispersion. The particles were prepared via a modified Tollens process, and the gelatin modifier was added prior to the reducing agent. The stability against aggregation of the AgNPs prepared by this method was more than one order of magnitude higher (on the basis of the critical coagulation concentration (CCC)) than that of AgNPs prepared via a similar method but without the assistance of gelatin. Their high stability against aggregation was confirmed over wide pH range (from 2 to 13) in which the particles did not exhibit rapid aggregation; such stability has not been previously reported for AgNPs. Additionally, gelatin not only fulfills the role of a unique stabilizer but also positively influences the modified Tollens process used to prepare the AgNPs. The diameter of the gelatin-modified AgNPs was substantially smaller in comparison to those prepared without gelatin. The polydispersity of the dispersion significantly narrowed. Moreover, the gelatin-stabilized AgNPs exhibited long-term stability against aggregation and maintained high antibacterial activity when stored for several months under ambient conditions. PMID:25098570

Sivera, Martin; Kvitek, Libor; Soukupova, Jana; Panacek, Ales; Prucek, Robert; Vecerova, Renata; Zboril, Radek

2014-01-01

225

Silver nanoparticles modified by gelatin with extraordinary pH stability and long-term antibacterial activity.  

PubMed

The potential for application of any nanoparticles, including silver nanoparticles (AgNPs), is strongly dependent on their stability against aggregation. Therefore, improvement of this parameter is a key task, especially in the case of AgNPs, because a correlation between size and biological activity has been demonstrated. In the present work, a natural stabilizer, gelatin, was investigated for the stabilization of AgNPs in an aqueous dispersion. The particles were prepared via a modified Tollens process, and the gelatin modifier was added prior to the reducing agent. The stability against aggregation of the AgNPs prepared by this method was more than one order of magnitude higher (on the basis of the critical coagulation concentration (CCC)) than that of AgNPs prepared via a similar method but without the assistance of gelatin. Their high stability against aggregation was confirmed over wide pH range (from 2 to 13) in which the particles did not exhibit rapid aggregation; such stability has not been previously reported for AgNPs. Additionally, gelatin not only fulfills the role of a unique stabilizer but also positively influences the modified Tollens process used to prepare the AgNPs. The diameter of the gelatin-modified AgNPs was substantially smaller in comparison to those prepared without gelatin. The polydispersity of the dispersion significantly narrowed. Moreover, the gelatin-stabilized AgNPs exhibited long-term stability against aggregation and maintained high antibacterial activity when stored for several months under ambient conditions. PMID:25098570

Sivera, Martin; Kvitek, Libor; Soukupova, Jana; Panacek, Ales; Prucek, Robert; Vecerova, Renata; Zboril, Radek

2014-01-01

226

Biochemical responses and mitochondrial mediated activation of apoptosis on long-term effect of aspartame in rat brain.  

PubMed

Aspartame, an artificial sweetener, is very widely used in many foods and beverages. But there are controversies about its metabolite which is marked for its toxicity. Hence it is believed to be unsafe for human use. Previous studies have reported on methanol exposure with involvements of free radicals on excitotoxicity of neuronal apoptosis. Hence, this present study is proposed to investigate whether or not chronic aspartame (FDA approved Daily Acceptable Intake (ADI),40 mg/kg bwt) administration could release methanol, and whether or not it can induce changes in brain oxidative stress status and gene and protein expression of anti-apoptotic Bcl-2 and pro-apoptotic Bax and caspase-3 in the rat brain region. To mimic the human methanol metabolism, Methotrexate (MTX)-treated Wistar strain male albino rats were used and after the oral administration of aspartame, the effects were studied along with controls and MTX-treated controls. Aspartame exposure resulted with a significant increase in the enzymatic activity in protein carbonyl, lipid peroxidation levels, superoxide dismutase, glutathione-S-transferase, glutathione peroxidase and catalase activity in (aspartame MTX)-treated animals and with a significant decrease in reduced glutathione, glutathione reductase and protein thiol, pointing out the generation of free radicals. The gene and protein expression of pro apoptotic marker Bax showed a marked increase whereas the anti-apoptotic marker Bcl-2 decreased markedly indicating the aspartame is harmful at cellular level. It is clear that long term aspartame exposure could alter the brain antioxidant status, and can induce apoptotic changes in brain. PMID:25009784

Ashok, Iyaswamy; Sheeladevi, Rathinasamy

2014-01-01

227

Constancy and variability of Strombolian eruptive activity: long-term analysis of infrared surveillance videos from Stromboli Volcano  

NASA Astrophysics Data System (ADS)

Persistent Strombolian activity characterizes open-conduit volcanoes worldwide. Among these, Stromboli (Italy) is one of the best monitored by permanent networks that include visible and infrared cameras. Continuous surveillance videos from the INGV archive allow us to parameterize the dynamics of explosive events in the period 2005-2009. Here we focus on three consecutive days per each year, by analyzing a total of 4275 explosive events from the different active vents. Via image analysis of the video frames, we obtained the time lapse among consecutive events, and duration and geometrical parameters (maximum height, width, and ejection angle) of individual jets. Long-term average values of the above parameters quantitatively define the activity baseline, as follows: inter-event time lapse 5 minutes (standard deviation 5 minutes); jet duration 15 s (5 s); jet height 70 m (24 m); jet width 33 m (10 m); jet axis at angle of 3° (16°) to the vertical. Significant deviations from these baseline values are observed over different (minute to year) time-scales, e.g.: peak jet durations and heights may reach up to 120 s and 251 m, respectively. The analysis of the mutual relationships among the eruptive parameters, and their temporal variation patterns at the different vents, provide a statistically based groundwork to define the dynamics of Strombolian activity. In this regard, a higher aspect ratio (height over width) of the jet seems to reflect increasing depth of the bubble burst beneath the magma free surface in the conduit, to be compared with seismic- and acoustic-derived information. Also, the remarkable constancy of jet angles at specific vents, notwithstanding the occurrence of a significant collapse of the whole crater area during the 2007 eruptive crisis, reveals self-similar resumption of the branching, shallow conduit system and provides insights into its connection to the feeder dike. The robust statistically based definition of the Stromboli behaviour can be helpful to determine the intensity thresholds of the activity and the areas prone to ejecta dispersal, relevant for hazard assessment.

Taddeucci, J.; Palladino, D. M.; Bernini, D.; Sottili, G.; Andronico, D.; Cristaldi, A.

2012-04-01

228

Continuous, Long-term, Cyclic, Varied Eruptive Activity Observed at NW Rota-1 Submarine Volcano, Mariana Arc  

NASA Astrophysics Data System (ADS)

NW Rota-1 is a conical, basaltic-andesite submarine volcano in the Mariana arc with a summit depth of 520 m. Eruptive activity was first witnessed here during remotely operated vehicle (ROV) dives in 2004, and was also observed during all four subsequent ROV expeditions in 2005, 2006, and 2009. Cyclic explosive bursts were documented by a portable hydrophone during the 2006 ROV dives. More recently, a year of instrumental monitoring data from a moored hydrophone and plume sensor show that the volcano was continuously active from February 2008 to February 2009, and that the cyclic character of the eruptions occurred with variable intensity and periodicity. The 2008-2009 hydrophone record includes explosive bursts every 1-2 minutes, with high acoustic amplitudes in the first half of the year and lower more variable amplitudes in the second half. In contrast, the moored turbidity sensor recorded major eruptive plumes on a time scale of every few days to weeks, and at approximately the same frequency throughout the year. This apparent disparity may be explained by the most recent ROV and portable hydrophone observations at NW Rota-1 in April 2009, which confirmed continuous and diverse eruptive activity with cyclicity over several time scales, from minutes to days. Visual observations at the eruptive vent provided new insight into the process of very slow lava extrusion on the seafloor. During slow extrusion (at rates of 1-2 m3/hr), lava spines rose in the eruptive vent, then gradually disintegrated into angular blocks as they cooled and were shoved aside by the next lava to emerge. Freshly erupted lava blocks periodically tumbled down the sides of a growing cone (40-m high and 300-m wide) that had been constructed by this process since the last visit in 2006. Thus auto-brecciation during slow lava extrusion underwater produces primary deposits that could easily be mistaken as secondary, and can construct substantial landforms on submarine arc volcanoes. Even during the slow extrusion in 2009, a portable hydrophone recorded rhythmic sounds similar to those recorded during explosive activity in 2006 but at lower sound levels. The burst-and-pause pattern in the acoustic data indicates that cyclic magmatic gas build-up and release is the dominant driver of the long-term eruptive activity at NW Rota-1 over a wide range of eruption rates.

Chadwick, B.; Dziak, R. P.; Baker, E. T.; Cashman, K. V.; Embley, R. W.; Ferrini, V.; de Ronde, C. E.; Butterfield, D. A.; Deardorff, N.; Haxel, J. H.; Matsumoto, H.; Fowler, M. J.; Walker, S. L.; Bobbitt, A. M.; Merle, S. G.

2009-12-01

229

Long-term variations in solar activity and a fossil solar magnetic field  

NASA Astrophysics Data System (ADS)

An analysis of sunspot groups from 1610 to the present has indicated that the Gnevyshev-Ohl (G-O) rule has reversal cycles with periods of 200 years (Tlatov, 2013). The next G-O rule reversal took place in the N22-23 Hale pair of cycles. In the following several pairs, odd cycles can be weaker than in the previous even cycles. Even and odd cycles differ because a magnetic field is added to the dynamo field. The value of such a field (about 5% of the dynamo field intensity) has been estimated based on latitudinal differences in the sunspot characteristics between even and odd cycles.

Tlatov, A. G.

2014-12-01

230

Characteristics of the Tropical Easterly Jet: Long-term trends and their features during active and break monsoon phases  

NASA Astrophysics Data System (ADS)

Using high-vertical resolution Indian mesosphere-stratosphere-troposphere (MST) radar and GPS sonde observations from Gadanki (13.5°N, 79.2°E), an attempt has been made for the first time to delineate the characteristics of Indian summer monsoon winds with special emphasis on the Tropical Easterly Jet stream (TEJ), its day-to-day, monthly, and interannual variability using observations available for more than a decade (1996-2008). For comparison, data available during 1996-2008 from routine radiosonde observations from nearby India Meteorological Department (IMD) observatory located at Chennai (13.0°N, 80.1°E) and National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR) reanalysis data sets have been considered. Relatively poor vertical resolution data from IMD lead to underestimation of the jet characteristics like jet width, vertical shear above and below the jet, and the wind reversal height. Although reanalysis data sets represented well the spatial variability, they underestimate the peak zonal winds by about 5 m/s when compared to Indian MST radar and GPS sonde observations. Large day-to-day variability of TEJ characteristics (peak jet speed, jet height, jet width, zonal wind reversal height, and vertical shear of zonal wind) over Gadanki is noticed. No significant trend is observed in peak jet speed using reanalysis data sets either over Gadanki grid or over jet core region in Indian summer monsoon months. However, MST radar and GPS sonde observations show increasing trend (˜1 m/s/yr) in peak jet speed particularly from the year 2000. Characteristics of the TEJ during active and break phases showed quite different features. Thus, statistics generated using the long-term database from Indian MST radar and GPS sonde provide valuable information for studying the TEJ characteristics and will be useful to incorporate in the future reanalysis data sets.

Roja Raman, M.; Jagannadha Rao, V. V. M.; Venkat Ratnam, M.; Rajeevan, M.; Rao, S. V. B.; Narayana Rao, D.; Prabhakara Rao, N.

2009-10-01

231

Different Phases of Long-Term Memory Require Distinct Temporal Patterns of PKA Activity after Single-Trial Classical Conditioning  

ERIC Educational Resources Information Center

The cAMP-dependent protein kinase (PKA) is known to play a critical role in both transcription-independent short-term or intermediate-term memory and transcription-dependent long-term memory (LTM). Although distinct phases of LTM already have been demonstrated in some systems, it is not known whether these phases require distinct temporal patterns…

Michel, Maximilian; Kemenes, Ildiko; Muller, Uli; Kemenes, Gyorgy

2008-01-01

232

Effects of long-term elevated CO2, warming, and prolonged drought on Pleurozium-associated diazotrophic activity and abundance  

NASA Astrophysics Data System (ADS)

Nitrogen (N2) fixation is the primary natural influx of N to terrestrial ecosystems, and changes in N2 fixation may have consequences for primary productivity and thus ecosystem function. We studied the activity and abundance of diazotrophs associated with the feather moss Pleurozium schreberi in a temperate heathland, after seven years of global change manipulations, including elevated atmospheric CO2 (510 ppm), increased temperature (0.5-1.5 ° C), and prolonged pre-summer droughts (4-6 weeks /year). Acetylene reduction assay was carried out monthly to monitor N2 fixation rates throughout one year, while nif H copy abundance, serving as a diazotroph abundance estimate, was measured by quantitative polymerase chain reaction (q-PCR). Prolonged summer droughts significantly increased both N2 fixation and nif H copy abundance, contrasting previous studies that demonstrate a direct negative correlation between N2 fixation and water availability. A shift in the relative abundance of N2-fixing bacteria from the green, upper parts of the moss stem to the lower, brown parts was observed. This shift could make diazotrophs less sensitive to desiccation, enabling N2 fixation to be upheld for longer during drought and thus causing higher abundance. Increased temperature likewise had a positive effect on the diazotroph abundance, although this did not translate into increased activity. Possibly, warming protects diazotrophs during extreme cold events, while actual N2 fixation is limited by water, disregarding a rise in potential N2 fixation caused by higher abundance. Increased CO2 caused no significant diazotroph response. Our study showed that long-term increase in temperature and recurrent drought events cause higher diazotroph abundance in Pleurozium schreberi and thus enhance the potential N2 fixations rate. Furthermore, our results indicate that diazotrophs may alter colonization patterns and thereby actively remain in the moss fraction less likely affected by desiccation. In consequence, Pleurozium-associated N2 fixation may become an even more important contributor of N for terrestrial ecosystems in a predicted future climate.

Dyrnum, Kristine; Priemé, Anders; Michelsen, Anders

2014-05-01

233

An Initial Evaluation of a Long-Term, Sustainable, Integrated Community-Based Physical Activity Program for Adults with Intellectual Disability  

ERIC Educational Resources Information Center

Background: Physical activity (PA) programs for adults with intellectual disability (ID) have positive impacts, at least in the short term. No research has been reported on the effect of long-term engagement in PA programs for adults with ID. This paper explores the physical and psychosocial benefits gained by two individuals with mild ID who…

Lante, Kerrie A.; Walkley, Jeff W.; Gamble, Merrilyn; Vassos, Maria V.

2011-01-01

234

Correlates of Long-Term Participation in a Physical Activity-Based Positive Youth Development Program for Low-Income Youth: Sustained Involvement and Psychosocial Outcomes  

ERIC Educational Resources Information Center

This study examined correlates of long-term participation in a positive youth development (PYD) program. Low-income youth (N = 215) age 8-13 of diverse ethnicity participating in a summer physical activity-based PYD program completed questionnaires at the beginning and end of the program (year 1) and at the beginning of year 2. Those with lower…

Ullrich-French, Sarah; McDonough, Meghan H.

2013-01-01

235

Modeling Cu Migration in CdTe Solar Cells Under Device-Processing and Long-Term Stability Conditions: Preprint  

SciTech Connect

An impurity migration model for systems with material interfaces is applied to Cu migration in CdTe solar cells. In the model, diffusion fluxes are calculated from the Cu chemical potential gradient. Inputs to the model include Cu diffusivities, solubilities, and segregation enthalpies in CdTe, CdS and contact materials. The model yields transient and equilibrium Cu distributions in CdTe devices during device processing and under field-deployed conditions. Preliminary results for Cu migration in CdTe photovoltaic devices using available diffusivity and solubility data from the literature show that Cu segregates in the CdS, a phenomenon that is commonly observed in devices after back-contact processing and/or stress conditions.

Teeter, G.; Asher, S.

2008-05-01

236

Cosmic Ray Hysteresis as Evidence for Time-dependent Diffusive Processes in the Long Term Solar Modulation  

NASA Technical Reports Server (NTRS)

A simple one-dimensional time-dependent diffusion-convection model for the modulation of cosmic rays is presented. This model predicts that the observed intensity at a given time is approximately equal to the intensity given by the time independent diffusion convection solution under interplanetary conditions which existed a time iota in the past, (U(t sub o) = U sub s(t sub o - tau)) where iota is the average time spent by a particle inside the modulating cavity. Delay times in excess of several hundred days are possible with reasonable modulation parameters. Interpretation of phase lags observed during the 1969 to 1970 solar maximum in terms of this model suggests that the modulating region is probably not less than 10 a.u. and maybe as much as 35 a.u. in extent.

Ogallagher, J. J.

1973-01-01

237

A long-term study of new particle formation in a coastal environment: Meteorology, gas phase and solar radiation implications.  

PubMed

New particle formation (NPF) was investigated at a coastal background site in Southwest Spain over a four-year period using a Scanning Particle Mobility Sizer (SMPS). The goals of the study were to characterise the NPF and to investigate their relationship to meteorology, gas phase (O3, SO2, CO and NO2) and solar radiation (UVA, UVB and global). A methodology for identifying and classifying the NPF was implemented using the wind direction and modal concentrations as inputs. NPF events showed a frequency of 24% of the total days analysed. The mean duration was 9.2±4.2h. Contrary to previous studies conducted in other locations, the NPF frequency reached its maximum during cold seasons for approximately 30% of the days. The lowest frequency took place in July with 10%, and the seasonal wind pattern was found to be the most important parameter influencing the NPF frequency. The mean formation rate was 2.2±1.7cm(-3)s(-1), with a maximum in the spring and early autumn and a minimum during the summer and winter. The mean growth rate was 3.8±2.4nmh(-1) with higher values occurring from spring to autumn. The mean and seasonal formation and growth rates are in agreement with previous observations from continental sites in the Northern Hemisphere. NPF classification of different classes was conducted to explore the effect of synoptic and regional-scale patterns on NPF and growth. The results show that under a breeze regime, the temperature indirectly affects NPF events. Higher temperatures increase the strength of the breeze recirculation, favouring gas accumulation and subsequent NPF appearance. Additionally, the role of high relative humidity in inhibiting the NPF was evinced during synoptic scenarios. The remaining meteorological variables (RH), trace gases (CO and NO), solar radiation, PM10 and condensation sink, showed a moderate or high connection with both formation and growth rates. PMID:25618818

Sorribas, M; Adame, J A; Olmo, F J; Vilaplana, J M; Gil-Ojeda, M; Alados-Arboledas, L

2015-04-01

238

Long-term testing  

NASA Astrophysics Data System (ADS)

Land-based gas turbines are significantly different from automotive gas turbines in that they are designed to operate for 50,000 h or greater (compared to 5,000-10,000 h). The primary goal of this research is to determine the long-term survivability of ceramic materials for industrial gas turbine applications. Research activities in this program focus on the evaluation of the static tensile creep and stress rupture (SR) behavior of three commercially available structural ceramics which have been identified by the gas turbine manufacturers as leading candidates for use in industrial gas turbines. For each material investigated, a minimum of three temperatures and four stresses will be used to establish the stress and temperature sensitivities of the creep and SR behavior. Because existing data for many candidate structural ceramics are limited to testing times less than 2,000 h, this program will focus on extending these data to times on the order of 10,000 h, which represents the lower limit of operating time anticipated for ceramic blades and vanes in gas turbine engines. A secondary goal of the program will be to investigate the possibility of enhancing life prediction estimates by combining interrupted tensile SR tests and tensile dynamic fatigue tests in which tensile strength is measured as a function of stressing rate. The third goal of this program will be to investigate the effects of water vapor upon the SR behavior of the three structural ceramics chosen for the static tensile studies by measuring the flexural strength as a function of stressing rate at three temperatures.

Ferber, M.; Graves, G. A., Jr.

239

Activation of the Basolateral Amygdala Induces Long-Term Enhancement of Specific Memory Representations in the Cerebral Cortex  

PubMed Central

The basolateral amygdala (BLA) modulates memory, particularly for arousing or emotional events, during post-training periods of consolidation. It strengthens memories whose substrates in part or whole are stored remotely, in structures such as the hippocampus, striatum and cerebral cortex. However, the mechanisms by which the BLA influences distant memory traces are unknown, largely because of the need for identifiable target mnemonic representations. Associative tuning plasticity in the primary auditory cortex (A1) constitutes a well-characterized candidate specific memory substrate that is ubiquitous across species, tasks and motivational states. When tone predicts reinforcement, the tuning of cells in A1 shifts toward or to the signal frequency within its tonotopic map, producing an over-representation of behaviorally important sounds. Tuning shifts have the cardinal attributes of forms of memory, including associativity, specificity, rapid induction, consolidation and long-term retention and are therefore likely memory representations. We hypothesized that the BLA strengthens memories by increasing their cortical representations. We recorded multiple unit activity from A1 of rats that received a single discrimination training session in which two tones (2.0 s) separated by 1.25 octaves were either paired with brief electrical stimulation (400 ms) of the BLA (CS+) or not (CS?). Frequency response areas generated by presenting a matrix of test tones (0.5–53.82 kHz, 0–70 dB) were obtained before training and daily for three weeks post-training. Tuning both at threshold and above threshold shifted predominantly toward the CS+ beginning on Day 1. Tuning shifts were maintained for the entire three weeks. Absolute threshold and bandwidth decreased, producing less enduring increases in sensitivity and selectivity. BLA-induced tuning shifts were associative, highly specific and long-lasting. We propose that the BLA strengthens memory for important experiences by increasing the number of neurons that come to best represent that event. Traumatic, intrusive memories might reflect abnormally extensive representational networks due to hyper-activity of the BLA consequent to the release of excessive amounts of stress hormones. PMID:23266792

Chavez, Candice M.; McGaugh, James L.; Weinberger, Norman M.

2013-01-01

240

Long-term trend of CH4 at northern mid-latitudes: Comparison between ground-based infrared solar and surface sampling measurements  

NASA Astrophysics Data System (ADS)

We report average tropospheric CH4 volume mixing ratios retrieved from a 27 year time series of high spectral resolution infrared solar absorption measurements recorded between May 1977 and July 2004 at the US National Solar Observatory station on Kitt Peak (31.9N,111.6W, 2.09 km altitude) and their comparison with surface in situ sampling measurements recorded between 1983 and 2004 at the Climate Monitoring and Diagnostics Laboratory (CMDL) station at Niwot Ridge, Colorado (40.0N,105.5W, 3013 m altitude). The two measurement sets therefore overlap for the 1983 2004 time period. An average tropospheric volume mixing ratios of 1814±48ppbv (1ppbv=10 per unit volume) has been derived from the solar absorption time series with a best-fit increase rate trend equal to 8.26±2.20 ppbv yr in 1983 decreasing to 1.94±3.69 ppbv yr in 2003. The CMDL measurements also show a continuous long-term CH4 volume mixing ratio rise, with subsequent slowing down. A mean ratio of the retrieved average tropospheric volume mixing ratio to the CMDL volume mixing ratio for the overlapping time period of 1.038±0.034 indicates agreement between both data sets within the quantified experimental errors.

Rinsland, Curtis P.; Goldman, Aaron; Elkins, James W.; Chiou, Linda S.; Hannigan, James W.; Wood, Stephen W.; Mahieu, Emmanuel; Zander, Rodolphe

2006-02-01

241

Solar and wind energy resources in Northern Hungary, including bi-variate distribution and long-term tendencies  

NASA Astrophysics Data System (ADS)

Spatial interpolation and mapping of renewable energy resources is an important task of potential estimation in case of atmospheric renewable energy sources. Its first steps, concerning global radiation measured at horizontal surfaces (not on optimally tilted ones) and near-surface wind speed measured at 10 m height above the surface (not at 60-120 m of contemporary wind-turbines). Based on these standard meteorological observations, experts of the Hungarian Meteorological Service elaborated a series of digital maps with 0.1 x 0.1 deg resolution compiled in the framework of the CarpatClim Project (www.carpatclim-eu.org). The grid-point values are based on homogenised data using MASH theory and software (SZENTIMREY, 1999). The interpolation has been performed by the MISH theory and software (SZENTIMREY and BIHARI, 2006). The study tackles the solar and wind energy in four aspects. Firstly, a trial for validation of the gridded data is provided by comparison a single station, Eger for 2001-2010 (global radiation) and 1996-2010 (wind speed cube). The horizontal distance between the closest grid-point and the station is less than 1 km. Gridded global radiation data perform very well comparing to the observations, based on various statistical parameters of the distribution, whereas for the wind speed cube, used as indicator of available energy, there is a considerable bias between the two sets of data. Secondly, the annual cycles of the area-mean global radiation and wind-speed are presented, based on the gridded data of a selected ca. 50x50 km2 (6x8 grid-points) region. Both the averages and standard deviations of the diurnal mean values are presented for the 1981-2010 reference period. Presenting the maps of the distribution within this area is our third aspect, considering both averages and standard deviations. Finally the point-wise trends are drown for both energy sources in the single grid-point used in the aspect one in 1981-2010, and also in the nearby located station for comparison. The trend of solar energy is positive, whereas the trend for wind energy (speed cube) is negative in the given 30 year period. Since these three decades exhibited mainly warming in the Northern Hemisphere, these trends might also be interpreted as responses to the large-scale forcing, though the observed behaviour does not necessarily mean causal relationship with the global tendencies. After these univariate analyses, correlation The study has been supported by the TÁMOP-4.2.2.A-11/1/KONV-2012-0016 Project in Hungary. Keywords: global radiation, wind energy, statistics, mapping, common distribution, climate change

Mika, Janos; Dobi-Wantuch, Ildiko; Tóth-Tarjányi Zsuzsanna, Zsuzsanna; Molnar, Zsofia; Kitti Csabai, Edina; Razsi, Andras

2014-05-01

242

Solar activity over different timescales  

NASA Astrophysics Data System (ADS)

The report deals with the “General History of the Sun” (multi-scale description of the long-term behavior of solar activity): the possibility of reconstruction. Time scales: • 100-150 years - the Solar Service. • 400 - instrumental observations. • 1000-2000 years - indirect data (polar auroras, sunspots seen with the naked eye). • Over-millennial scale (Holocene) -14? (10Be) Overview and comparison of data sets. General approaches to the problem of reconstruction of solar activity indices on a large timescale. North-South asymmetry of the sunspot formation activity. 200-year cycle over the “evolution timescales”.The relative contribution of the large-scale and low-latitude. components of the solar magnetic field to the general geomagnetic activity. “Large-scale” and low-latitude sources of geomagnetic disturbances.

Obridko, Vladimir; Nagovitsyn, Yuri

243

Long Term Effect of Curcumin in Regulation of Glycolytic Pathway and Angiogenesis via Modulation of Stress Activated Genes in Prevention of Cancer  

PubMed Central

Oxidative stress, an important factor in modulation of glycolytic pathway and induction of stress activated genes, is further augmented due to reduced antioxidant defense system, which promotes cancer progression via inducing angiogenesis. Curcumin, a naturally occurring chemopreventive phytochemical, is reported to inhibit carcinogenesis in various experimental animal models. However, the underlying mechanism involved in anticarcinogenic action of curcumin due to its long term effect is still to be reported because of its rapid metabolism, although metabolites are accumulated in tissues and remain for a longer time. Therefore, the long term effect of curcumin needs thorough investigation. The present study aimed to analyze the anticarcinogenic action of curcumin in liver, even after withdrawal of treatment in Dalton's lymphoma bearing mice. Oxidative stress observed during lymphoma progression reduced antioxidant enzyme activities, and induced angiogenesis as well as activation of early stress activated genes and glycolytic pathway. Curcumin treatment resulted in activation of antioxidant enzyme super oxide dismutase and down regulation of ROS level as well as activity of ROS producing enzyme NADPH:oxidase, expression of stress activated genes HIF-1?, cMyc and LDH activity towards normal level. Further, it lead to significant inhibition of angiogenesis, observed via MMPs activity, PKC? and VEGF level, as well as by matrigel plug assay. Thus findings of this study conclude that the long term effect of curcumin shows anticarcinogenic potential via induction of antioxidant defense system and inhibition of angiogenesis via down regulation of stress activated genes and glycolytic pathway in liver of lymphoma bearing mice. PMID:24932681

Das, Laxmidhar; Vinayak, Manjula

2014-01-01

244

The long-term behavior of the main peak of the dayside ionosphere of Venus during solar cycle 21 and its implications on the effect of the solar cycle upon the electron temperature in the main peak region  

NASA Technical Reports Server (NTRS)

Results are presented on the long-term behavior of the main peak electron density in the Venus ionosphere during the solar cycle 21, based on 104 radio occultation measurements of the vertical electron density profile in the dayside ionosphere of Venus carried out aboard the Pioneer Venus Orbiter spacecraft (along with published data on 11 Venera 9-10 measurements). The equation representing the electron temperature at h = 140 km is presented. The results imply that the electron temperature at h = 140 km decreased by about 25 percent from solar maximum to solar minimum, compared to a decrease of 50-75 percent above 200 km found by Kliore and Mullen (1989).

Kliore, Arvydas J.; Mullen, Luke F.

1989-01-01

245

The long-term behavior of the main peak of the dayside ionosphere of Venus during solar cycle 21 and its implications on the effect of the solar cycle upon the electron temperature in the main peak region  

NASA Astrophysics Data System (ADS)

Results are presented on the long-term behavior of the main peak electron density in the Venus ionosphere during the solar cycle 21, based on 104 radio occultation measurements of the vertical electron density profile in the dayside ionosphere of Venus carried out aboard the Pioneer Venus Orbiter spacecraft (along with published data on 11 Venera 9-10 measurements). The equation representing the electron temperature at h = 140 km is presented. The results imply that the electron temperature at h = 140 km decreased by about 25 percent from solar maximum to solar minimum, compared to a decrease of 50-75 percent above 200 km found by Kliore and Mullen (1989).

Kliore, Arvydas J.; Mullen, Luke F.

1989-10-01

246

Reduction of K1 Uptake in Glia Prevents Long-Term Depression Maintenance and Causes Epileptiform Activity  

Microsoft Academic Search

Extracellular cesium causes synchronous, interictal-like burst- ing and prevents maintenance of long-term depression (LTD) in the CA1 hippocampal region. We have investigated the cellular mechanisms underlying cesium actions. Whole-cell recordings showed that brief (2 min) bath exposures to cesium caused pyramidal cell hyperpolarization associated with decreased membrane conductance attributable to blockade of an inward h-type current. After prolonged (.2 min)

Damir Janigro; Sonia Gasparini; Raimondo D'Ambrosio; Guy McKhann; Dario DiFrancesco

247

The role of microglia activation in the development of sepsis-induced long-term cognitive impairment.  

PubMed

Oxidative stress and inflammation is likely to be a major step in the development of sepsis-associated encephalopathy (SAE) and long-term cognitive impairment. To date, it is not known whether brain inflammation and oxidative damage are a direct consequence of systemic inflammation or whether these events are driven by brain resident cells, such as microglia. Therefore, the aim of this study is to evaluate the effect of minocycline on behavioral and neuroinflammatory parameters in rats submitted to sepsis. Male Wistar rats were subjected to sepsis by cecal ligation and puncture (CLP). The animals were divided into sham-operated (Sham+control), sham-operated plus minocycline (sham+MIN), CLP (CLP+control) and CLP plus minocycline (CLP+MIN) (100?g/kg, administered as a single intracerebroventricular (ICV) injection). Some animals were killed 24h after surgery to assess the breakdown of the blood brain barrier, cytokine levels, oxidative damage to lipids (TBARS) and proteins in the hippocampus. Some animals were allowed to recover for 10days when step-down inhibitory avoidance and open-field tasks were performed. Treatment with minocycline prevented an increase in markers of oxidative damage and inflammation in the hippocampus after sepsis. This was associated with an improvement in long-term cognitive performance. In conclusion, we demonstrated that the inhibition of the microglia by an ICV injection of minocycline was able to decrease acute brain oxidative damage and inflammation as well as long-term cognitive impairment in sepsis survivors. PMID:25019583

Michels, Monique; Vieira, Andriele S; Vuolo, Francieli; Zapelini, Hugo Galvane; Mendonça, Bruna; Mina, Francielle; Dominguini, Diogo; Steckert, Amanda; Schuck, Patrícia Fernanda; Quevedo, João; Petronilho, Fabrícia; Dal-Pizzol, Felipe

2015-01-01

248

X-RAY, FUV, AND UV OBSERVATIONS OF {alpha} CENTAURI B: DETERMINATION OF LONG-TERM MAGNETIC ACTIVITY CYCLE AND ROTATION PERIOD  

SciTech Connect

Over the last couple of decades we have been carrying out a study of stellar magnetic activity, dynamos, atmospheric physics, and spectral irradiances from a sample of solar-type G0-5 V stars with different ages. One of the major goals of this program is to study the evolution of the Sun's X-ray through NUV spectral irradiances with age. Of particular interest is the determination of the young Sun's elevated levels of high-energy fluxes because of the critical roles that X-ray (coronal) through FUV (transition region (TR), chromospheric) emissions play on the photochemical and photoionization evolution (and possible erosion) of early, young planetary atmospheres and ionospheres. Motivated by the current exoplanetary search missions (such as Kepler and CoRoT, along with the planned Space Interferometry Mission and Darwin/Terrestrial Planet Finder missions) that are hunting for Earth-size planets in the habitable zones (liquid water) of nearby main-sequence G-M stars, we are expanding our program to cooler, less luminous, but very importantly, much more numerous main-sequence K-type stars, such as {alpha} Centauri B. The long life (2-3x longer than the Sun) and slow evolution of K stars provide nearly constant energy sources for possible hosted planets. This program parallels our 'Sun in Time' program, but extends the study to stars with deeper convective zone depths. Presented here are X-ray (coronal; ROSAT, Chandra, XMM-Newton), UV (TR; International Ultraviolet Explorer (IUE)), NUV (chromospheric; IUE), and recently acquired FUV (TR/chromospheric; FUSE Cycles 7/8) observations of the K1 V star {alpha} Cen B (HD 128621; V = 1.33; (B - V) = +0.88; {tau} = 5.6 {+-} 0.6 Gyr). These combined high-energy measures provide a more complete look into the nature of {alpha} Cen B's magnetic activity and X-ray-UV radiances. We find that {alpha} Cen B has exhibited significant long-term variability in X-ray through NUV emission fluxes, indicating a solar-like long-term activity cycle of P{sub cycle} = 8.84 {+-} 0.4 years. In addition, analysis of the short-term rotational modulation of mean light due to the effects of magnetically active regions has yielded a well-determined rotation period of P{sub rotation} = 36.2 {+-} 1.4 days. {alpha} Cen B is the only old main-sequence K star with a reliably determined age and rotation period, and for early K stars, as in the case of the Sun for G2 V stars, is an important calibrator for stellar age/rotation/activity relations.

DeWarf, L. E.; Guinan, E. F.; Datin, K. M., E-mail: Laurence.DeWarf@Villanova.ed [Department of Astronomy and Astrophysics, Villanova University, 800 Lancaster Avenue, Villanova, PA 19085 (United States)

2010-10-10

249

Long-term efficacy and safety of once-daily mesalazine granules for the treatment of active ulcerative colitis  

PubMed Central

In 1977, 5-aminosalicylic acid (5-ASA) was discovered as a therapeutically active moiety of sulfasalazine (SASP) and was launched for topical and oral therapy of ulcerative colitis (UC) in 1984. As a first-step, delivery systems had to be developed to protect 5-ASA against absorption in the upper gastrointestinal tract, resulting in different and competing strategies (azo compounds, controlled release, and pH-dependent release). In a second step, at the beginning of the new century, coinciding with the expiration of patent protection for the first 5-ASA formulations, two component composite release mechanisms (pH-dependent and controlled release) were developed. Furthermore, the drug was formulated as granules instead of tablets, allowing higher unit strengths compared with tablets. Neither Salofalk Granu-Stix®, nor MMX 5-ASA, nor Pentasa® granules have initially been developed for once-daily (OD) dosing. A review of the achievements of 20 years of 5-ASA development has demonstrated that 5-ASA has equal efficacy compared with SASP at best, that there are no measurable differences in efficacy between various 5-ASA preparations, and that in a group of patients tolerating SASP, adverse event profiles of SASP and 5-ASA did not differ significantly, with SASP being the far cheaper substance. Therefore, drug adherence came into focus as a new goal for improving UC therapy. Although adherence is a complex and multifactorial construct, a simple dosing schedule may contribute to higher drug adherence and better efficacy of treatment. Simultaneously, the US 5-ASA market, estimated to be worth US$1.4 billion, is expected to grow continuously. Naturally, this very competitive market is not only driven by scientific progress but also by commercial interests. Thus, patents for minor changes to the formulation may serve as protection against drug companies trying to launch generic versions. Randomized controlled trials performed on OD dosing in induction of remission have demonstrated that OD administration of 5-ASA is as effective as conventional dosing in mild to moderate active UC. The three 5-ASA products MMX, Salofalk®, and Pentasa® employed in those studies so far have not shown differences in efficacy between OD and conventional dosing. No differences regarding safety outcomes have been detected between OD and conventional dosing, including incidence of adverse events, serious adverse events, or withdrawal from treatment due to an adverse event. Although the majority of patients prefer OD dosing to conventional dosing, it was not possible to detect differences in adherence between OD and multiple dose regimens in the clinical trial setting. Well-designed and controlled large-scale community-based studies are necessary to further investigate and prove the point of improved long-term adherence and treatment efficacy in OD dosing. PMID:25285021

Böhm, Stephan Karl; Kruis, Wolfgang

2014-01-01

250

Effect of long-term fertilizers and manure application on microbial biomass and microbial activity of a tropical agricultural soil  

Microsoft Academic Search

We investigated some aspects of soil quality and community-level physiological profiles (CLPP) of bacteria in soil under a\\u000a long-term (37 years) trial with either exclusive inorganic fertilizers or fertilizers combined with farmyard manure cultivated\\u000a with jute–rice–wheat system. The treatments consisted of 100% recommended dose (RD) of NPK, 150% RD of NPK, 100% RD of N,\\u000a 100% RD of NPK?+?FYM (10 t ha?1?year?1),

Amrita Chakraborty; Kalyan Chakrabarti; Ashis Chakraborty; Sagarmoy Ghosh

2011-01-01

251

Effects of Long-Term Acupuncture Treatment on Resting-State Brain Activity in Migraine Patients: A Randomized Controlled Trial on Active Acupoints and Inactive Acupoints  

PubMed Central

Background Acupuncture has been commonly used for preventing migraine attacks and relieving pain during a migraine, although there is limited knowledge on the physiological mechanism behind this method. The objectives of this study were to compare the differences in brain activities evoked by active acupoints and inactive acupoints and to investigate the possible correlation between clinical variables and brain responses. Methods and Results A randomized controlled trial and resting-state functional magnetic resonance imaging (fMRI) were conducted. A total of eighty migraineurs without aura were enrolled to receive either active acupoint acupuncture or inactive acupoint acupuncture treatment for 8 weeks, and twenty patients in each group were randomly selected for the fMRI scan at the end of baseline and at the end of treatment. The neuroimaging data indicated that long-term active acupoint therapy elicited a more extensive and remarkable cerebral response compared with acupuncture at inactive acupoints. Most of the regions were involved in the pain matrix, lateral pain system, medial pain system, default mode network, and cognitive components of pain processing. Correlation analysis showed that the decrease in the visual analogue scale (VAS) was significantly related to the increased average Regional homogeneity (ReHo) values in the anterior cingulate cortex in the two groups. Moreover, the decrease in the VAS was associated with increased average ReHo values in the insula which could be detected in the active acupoint group. Conclusions Long-term active acupoint therapy and inactive acupoint therapy have different brain activities. We postulate that acupuncture at the active acupoint might have the potential effect of regulating some disease-affected key regions and the pain circuitry for migraine, and promote establishing psychophysical pain homeostasis. Trial Registration Chinese Clinical Trial Registry ChiCTR-TRC-13003635 PMID:24915066

Zhao, Ling; Liu, Jixin; Zhang, Fuwen; Dong, Xilin; Peng, Yulin; Qin, Wei; Wu, Fumei; Li, Ying; Yuan, Kai; von Deneen, Karen M.; Gong, Qiyong; Tang, Zili; Liang, Fanrong

2014-01-01

252

Long-term geochemical monitoring in seismically active areas of the apennine chain (italy): implications for seismic hazard evaluation  

NASA Astrophysics Data System (ADS)

The long-term and mid-term monitoring geochemical monitoring of thermal waters and gas vents, as well as the dissolved gases, carried out in seismic areas of the Apennine Chain allowed the detection of temporal anomalies of both the chemical and isotope composition of the investigated fluids. The recorded geochemical anomalies were related to "physical" changes as observed during and after the last seismic crisis occurred in the investigated area (Umbria-Marche region) where co-seismic displacement and subsidence, post-seismic long-term deformative process and significant pre-seismic slip along the Umbria-Marche earthquake fault were collected. However, the occurrence of "physical" phenomena did not appear directly linked to local seismic events. Geochemical variations actually seem to have been induced by permeability variations related to crustal stresses even in the absence of elastic energy release. Hence, both physical and chemical changes are connected to the seismogenic process as a whole. We propose that, since geochemical anomalies can be detected during the entire seismogenic process, a correct approach to the geochemical monitoring may provide a powerful support to the widely debated question of earthquake prediction and may add some constraints for a deterministic approach to the seismic risk evaluation.

Caracausi, A.; Italiano, F.; Martinelli, G.; Paonita, A.; Rizzo, A.

2003-04-01

253

Bacterial response to a continuous long-term exposure of silver nanoparticles at sub-ppm silver concentrations in a membrane bioreactor activated sludge system.  

PubMed

Silver nanoparticles (nanosilver or AgNPs) have excellent antimicrobial properties. Because of their increasing use, there is a concern about the potential impact of AgNPs in wastewater treatment systems. This study investigated the long-term effects of AgNPs (continuous loading for more than 60 days) on membrane bioreactor (MBR) activated sludge performance. At the influent AgNP concentration of 0.10 mg Ag/L, there was no significant difference in effluent water quality or bacterial activities before and after AgNP exposure. Nitrifying bacterial community structure was relatively stable before and after the long-term AgNP loading. Both ammonia-oxidizing bacteria (AOB) Nitrosomonas spp. and Nitrosospira spp. were present while Nitrospira spp. was the dominant nitrite-oxidizing bacterial species throughout this study. Abundance of silver resistance gene silE in the MBR, however, increased by 50-fold 41 days after the AgNP exposure, and then decreased with continuous AgNP exposure. The long-term nanosilver exposure did not change the membrane fouling rate although extracellular polymeric substances (EPS) concentration increased significantly after nanosilver dosing. The results suggest that AgNPs at the influent concentrations of 0.10 mg/L and below have almost no impact on activated sludge wastewater treatment performance, as activated sludge can effectively reduce nanosilver toxicity by adsorbing or precipitating AgNPs and silver ions (Ag(+)) released from the dissolution of AgNPs. PMID:24210505

Zhang, Chiqian; Liang, Zhihua; Hu, Zhiqiang

2014-03-01

254

Response of aerobic granular sludge to the long-term presence to nanosilver in sequencing batch reactors: Reactor performance, sludge property, microbial activity and community.  

PubMed

The increasing use of silver nanoparticles (Ag NPs) raises concerns about their potential toxic effects on the environment. Granular shape sludge is a special type of microbial aggregate. The response of aerobic granular sludge (AGS) to the long-term presence of Ag NPs has not been well studied. In this study, AGS was exposed to 5 and 50mg/L Ag NPs in sequence batch reactors (SBRs) for 69days, and its response was evaluated based on the sludge properties, microbial activity and community, and reactor performance. The results showed that Ag NPs caused inhibition to microbial activities of AGS from Day 35. At the end of 69days of Ag NPs exposure, the microbial activity of AGS was significantly inhibited in terms of inhibitions of the ammonia oxidizing rate (33.0%), respiration rate (17.7% and 45.6%) and denitrification rate (6.8%), as well as decreases in the ammonia mono-oxygenase and nitrate reductase activities. During the long-term exposure, the AGS maintained its granular shape and large granule size (approximately 900?m); the microbial community of AGS slightly changed, but the dominant microbial population remained. Overall, the AGS tolerated the toxicity of Ag NPs well, but a long-term exposure may produce chronic toxicity to the AGS, which is concerning. PMID:25460955

Quan, Xiangchun; Cen, Yan; Lu, Fang; Gu, Lingyun; Ma, Jingyun

2015-02-15

255

Stimulation of gene expression and activity of antioxidant related enzyme in Sprague Dawley rat kidney induced by long-term iron toxicity.  

PubMed

The trace elements such as iron are vital for various enzyme activities and for other cellular proteins, but iron toxicity causes the production of reactive oxygen species (ROS) that causes alterations in morphology and function of the nephron. The present study was designed to determine the effect of long-term iron overload on the renal antioxidant system and to determine any possible correlation between enzymatic and molecular levels. Our data showed that reduced glutathione (GSH) levels, which is a marker for oxidative stress, strikingly decreased with a long-term iron overload in rat kidney. While renal mRNA levels of glucose 6-phosphate dehydrogenase (G6pd), 6-phosphogluconate dehydrogenase (6pgd) and glutathione peroxidase (Gpx) were significantly affected in the presence of ferric iron, no changes were seen for glutathione reductase (Gsr) and glutathione S-transferases (Gst). While the iron affected the enzymatic activity of G6PD, GSR, GST, and GPX, it had no significant effect on 6PGD activity in the rat kidney. In conclusion, we reported here that the gene expression of G6pd, 6pgd, Gsr, Gpx, and Gst did not correlate to enzyme activity, and the actual effect of long-term iron overload on renal antioxidant system is observed at protein level. Furthermore, the influence of iron on the renal antioxidant system is different from its effect on the hepatic antioxidant system. PMID:25038477

Budak, Harun; Kocpinar, Enver Fehim; Gonul, Nurdan; Ceylan, Hamid; Erol, Huseyin Serkan; Erdogan, Orhan

2014-11-01

256

Long-Term Effects of a Standardized Complex Mixture of Urban Dust Particulate on the Metabolic Activation of Carcinogenic Polycyclic Aromatic Hydrocarbons in Human Cells in Culture  

Microsoft Academic Search

Humans are exposed to complex mixtures of polycyclic aromatic hydrocarbons in the atmosphere. We examined the long term effects of a standard reference material (SRM) 1649a over time on the metabolic activation and DNA adduct formation by two carcinogenic PAHs, benzo(a)pyrene (BP) and dibenzo(a,l)pyrene (DBP) in the human mammary carcinoma derived cell line MCF-7. PAH-DNA adduct analysis, cytochrome P450 (CYP)

Tamara Musafia-Jeknic; Brinda Mahadevan; Clifford Pereira; William M Baird

2005-01-01

257

Reassessment of the long-term trends in surface solar radiation over Europe by means of a homogenized dataset (1939-2011)  

NASA Astrophysics Data System (ADS)

A widespread reduction of surface solar radiation (SSR) has been well established and documented from the 1950s to the 1980s, and an opposite trend has been detected in many regions of the world since the 1980s. This decrease and increase in SSR has been defined as "global dimming" and "brightening" periods, respectively. Nevertheless, the importance of the availability of high-quality SSR data in order to estimate long-term trends is well known, particularly with respect to the quality and homogeneity of the databases. This work presents a reassessment and update until December 2011 of the trends in SSR over Europe, which is based on the 56 longest and homogenized series available at the Global Energy Balance Archive (GEBA). The mean annual SSR series show an increase from the late 1930s to the early 1950s, followed by a reduction until mid-1980s, and ending with an increase up to 2011. During the period 1939-2011 the trend is negative and significant on annual basis, with a decrease of 3.6 Wm-2 over the whole period. This implies that the trend in SSR cannot be at the origin of the warming over Europe observed during this time. Similar results are obtained in different regions, especially in Central and Eastern Europe. On the other hand, updated records until 2013 in Potsdam (Germany) confirm that the winter 2013 was the least sunny one since the beginning of measurements in the 1930s.

Sanchez-Lorenzo, Arturo; Wild, Martin; Guijarro, Jose; Brunetti, Michele; Mystakidis, Stefanos; Hakuba, Maria

2014-05-01

258

Vitesses de glissement à long terme et dislocations cosismiques caractéristiques : clés du fonctionnement des failles actives et de l'aléa sismique  

NASA Astrophysics Data System (ADS)

Over periods of thousands of years, active faults tend to slip at constant rates. Pioneer studies of large Asian faults show that cosmogenic radionuclides ( 10Be, 26Al) provide an unparalleled tool to date surface features, whose offsets yield the longest records of recent cumulative movement. The technique is thus uniquely suited to determine long-term (10-100 ka) slip rates. Such rates, combined with coseismic slip-amounts, can give access to recurrence times of earthquakes of similar sizes. Landform dating - morphochronology - is therefore essential to understand fault-behaviour, evaluate seismic hazard, and build physical earthquake models. It is irreplaceable because long-term slip-rates on interacting faults need not coincide with GPS-derived, interseismic rates, and can be difficult to obtain from paleo-seismological trenching.

Tapponnier, Paul; Ryerson, Frederick James; Van der Woerd, Jerome; Mériaux, Anne-Sophie; Lasserre, Cécile

2001-11-01

259

[Radiometers performance attenuation and data correction in long-term observation of total radiation and photosynthetically active radiation in typical forest ecosystems in China].  

PubMed

Based on the total radiation and photosynthetically active radiation (PAR) observations with net radiometer (CNR1) and quantum sensor (Li-190SB) in 4 ChinaFLUX forest sites (Changbaishan, Qianyanzhou, Dinghushan, and Xishuangbanna) in 2003-2008, this paper analyzed the uncertainties and the radiometers performance changes in long-term and continuous field observation. The results showed that the 98% accuracy of the total radiation measured with CNR1 (Q(cNR1)) could satisfy the technical criterion for the sites except Xishuangbanna where the Q(CNR1) was averagely about 7% lower than Q(CM11), the radiation measured with high accuracy pyranometer CM11. For most sites, though the temperature had definite effects on the performance of CNR1, the effects were still within the allowable range of the accuracy of the instrument. Besides temperature, the seasonal fog often occurred in tropical rain forests in Xishuangbanna also had effects on the performance of CNR1. Based on the long-term variations of PAR, especially its ratio to total radiation in the 4 sites, it was found that quantum sensor (Li-190SB) had obvious performance attenuation, with the mean annual attenuation rate being about 4%. To correct the observation error caused by Li-190SB, an attempt was made to give a post-correction of the PAR observations, which could basically eliminate the quantum sensor's performance attenuation due to long-term field measurement. PMID:22303674

Zhu, Zhi-Lin; Sun, Xiao-Min; Yu, Gui-Rui; Wen, Xue-Fa; Zhang, Yi-Ping; Han, Shi-Jie; Yan, Jun-Hua; Wang, Hui-Min

2011-11-01

260

Focal epileptiform activity in the prefrontal cortex is associated with long-term attention and sociability deficits.  

PubMed

There is a well-described association between childhood epilepsy and pervasive cognitive and behavioral deficits. Often these children not only have ictal EEG events, but also frequent interictal abnormalities. The precise role of these interictal discharges in cognition remains unclear. In order to understand the relationship between frequent epileptiform discharges during neurodevelopment and cognition later in life, we developed a model of frequent focal interictal spikes (IIS). Postnatal day (p) 21 rats received injections of bicuculline methiodine into the prefrontal cortex (PFC). Injections were repeated in order to achieve 5 consecutive days of transient inhibitory/excitatory imbalance resulting in IIS. Short-term plasticity (STP) and behavioral outcomes were studied in adulthood. IIS is associated with a significant increase in STP bilaterally in the PFC. IIS rats did not show working memory deficits, but rather showed marked inattentiveness without significant alterations in motivation, anxiety or hyperactivity. Rats also demonstrated significant deficits in social behavior. We conclude that GABAergic blockade during early-life and resultant focal IIS in the PFC disrupt neural networks and are associated with long-term consequences for behavior at a time when IIS are no longer present, and thus may have important implications for ADHD and autism spectrum disorder associated with childhood epilepsy. PMID:24269731

Hernan, Amanda E; Alexander, Abigail; Jenks, Kyle R; Barry, Jeremy; Lenck-Santini, Pierre-Pascal; Isaeva, Elena; Holmes, Gregory L; Scott, Rod C

2014-03-01

261

Long-term effect of irrigation with water from sewage treatment plant on AMF biodiversity and microbial activities.  

NASA Astrophysics Data System (ADS)

Shortage of water is one of the most important environmental problem in the Mediterranean areas that implicates the search for strategies for saving good quality water. The use of treated waste water for the irrigation of agricultural land can be a good solution for this problem because it reduces the utilization of fresh water and potentially could improve soil key parameters, but can modify physical-chemical and biological properties of the same. The aim of this work was to study the effect of long-term irrigation with treated waste water on microbial diversity, mainly arbuscular mycorrhizal fungi (AMF) of the soil and other properties related with the microbial community. The experiment was developed in an agricultural area with Citrus orchard, located in Alicante in the southeast Spain. Here, we tested whether the communities of AMF as well as soil microbial properties were affected by irrigation with water coming from sewage treatment plant during 40 years in a soil. To carry out this study the soil properties (dehydrogenase, urease, protease-BAA, acid phosphatase, ?-glucosidase, glomalin related soil protein, microbial biomass C and aggregate stability) and AMF diversity (the AM fungal small sub-unit (SSU) rRNA genes were subjected to PCR, cloning, sequencing and phylogenetic analyses) were analysed in the soil from two different plots with the same soil but with different type of irrigation (irrigated with fresh water and irrigated with treated water). The first results did not show significant differences in some soil properties between soil irrigated with water treated or not.

Alguacil, M. M.; Torrecillas, E.; Lozano, Z.; Torres, M. P.; Garcia-Orenes, F.; Roldan, A.

2012-04-01

262

Short and long-term lifestyle coaching approaches used to address diverse participant barriers to weight loss and physical activity adherence  

PubMed Central

Background Individual barriers to weight loss and physical activity goals in the Diabetes Prevention Program, a randomized trial with 3.2 years average treatment duration, have not been previously reported. Evaluating barriers and the lifestyle coaching approaches used to improve adherence in a large, diverse participant cohort can inform dissemination efforts. Methods Lifestyle coaches documented barriers and approaches after each session (mean session attendance?=?50.3?±?21.8). Subjects were 1076 intensive lifestyle participants (mean age?=?50.6 years; mean BMI?=?33.9 kg/m2; 68% female, 48% non-Caucasian). Barriers and approaches used to improve adherence were ranked by the percentage of the cohort for whom they applied. Barrier groupings were also analyzed in relation to baseline demographic characteristics. Results Top weight loss barriers reported were problems with self-monitoring (58%); social cues (58%); holidays (54%); low activity (48%); and internal cues (thought/mood) (44%). Top activity barriers were holidays (51%); time management (50%); internal cues (30%); illness (29%), and motivation (26%). The percentage of the cohort having any type of barrier increased over the long-term intervention period. A majority of the weight loss barriers were significantly associated with younger age, greater obesity, and non-Caucasian race/ethnicity (p-values vary). Physical activity barriers, particularly thought and mood cues, social cues and time management, physical injury or illness and access/weather, were most significantly associated with being female and obese (p? 90% long term) and regularly reviewed self-monitoring skills. More costly approaches were used infrequently during the first 16 sessions (?10%) but increased over 3.2 years. Conclusion Behavioral problem solving approaches have short and long term dissemination potential for many kinds of participant barriers. Given minimal resources, increased attention to training lifestyle coaches in the consistent use of these approaches appears warranted. PMID:24521153

2014-01-01

263

Long-term melatonin administration attenuates low-LET ?-radiation-induced lymphatic tissue injury during the reproductively active and inactive phases of Indian palm squirrels (Funambulus pennanti)  

PubMed Central

A comparative analysis of low linear energy transfer (LET) ?-radiation-induced damage in the lymphatic tissue of a tropical seasonal breeder, Indian palm squirrel (Funambulus pennanti), during its reproductively active phase (RAP) and inactive phase (RIP) was performed with simultaneous investigation of the effects of long-term melatonin pre-treatment (100 ?g/100 g body weight). A total of 120 squirrels (60 during RAP and 60 during RIP) were divided into 12 groups and sacrificed at 4, 24, 48, 72 and 168 h following 5 Gy ?-radiation exposure; control groups were excluded from exposure. Total leukocyte count and absolute lymphocyte count (ALC) and melatonin only of peripheral blood, stimulation index, thiobarbituric-acid-reactive substances (TBARS) level, superoxide dismutase (SOD) activity, and the apoptotic index of spleen as analysed by terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick-end labelling (TUNEL) noted at observed time-points were significantly reduced in melatonin pre-treated groups during RAP and RIP. Long-term melatonin pre-treatment mitigated radiation-induced alterations more prominently during RIP, as assessed by ALC, TBARS, SOD, TUNEL and caspase-3 activity, at some time-points. Our results demonstrate an inhibitory role of melatonin on caspase-3 activity in splenocytes during RAP and RIP following ?-radiation-induced caspase-mediated apoptosis. Hence, we propose that melatonin might preserve the viability of immune cells of a seasonal breeder against background radiation, which is constantly present in the environment. PMID:20139262

Sharma, S; Haldar, C; Chaube, S K; Laxmi, T; Singh, S S

2010-01-01

264

Workshop on Solar Activity, Solar Wind, Terrestrial Effects, and Solar Acceleration  

NASA Technical Reports Server (NTRS)

A summary of the proceedings from the workshop are presented. The areas covered were solar activity, solar wind, terrestrial effects, and solar acceleration. Specific topics addressed include: (1) solar cycle manifestations, both large and small scale, as well as long-term and short-term changes, including transients such as flares; (2) sources of solar wind, as identified by interplanetary observations including coronal mass ejections (CME's) or x-ray bright points, and the theory for and evolution of large-scale and small-scale structures; (3) magnetosphere responses, as observed by spacecraft, to variable solar wind and transient energetic particle emissions; and (4) origin and propagation of solar cosmic rays as related to solar activity and terrestrial effects, and solar wind coronal-hole relationships and dynamics.

1992-01-01

265

A long-term, prospective, cohort study on the performance of right ventricular pacing leads: comparison of active-fixation with passive-fixation leads.  

PubMed

Active-fixation pacing leads allow the use of selective pacing sites. We evaluated their long-term performance versus passive-fixation leads in 199 newly implanted patients (n = 100 active and n = 99 passive). Postoperative pacing thresholds in the active group were higher than in the passive group (0.85 ± 0.31?V vs. 0.53 ± 0.21?V at baseline, P < 0.001). The active thresholds fell to 0.72 ± 0.23?V at 5 years with a significant drop at one month (0.68 ± 0.53?V, P = 0.003). The passive thresholds slightly increased to 0.72 ± 0.31?V at five years. Differences between groups were significant until three years (all P < 0.05). Active impedances were generally lower than passive impedances (600.44 ± 94.31? vs. 683.14 ± 110.98? at baseline), and both showed significant reductions at one month to 537.96 ± 147.43? in the active group, and after three months to 643.85 ± 82.40? in the passive group (both P < 0.01 vs. baseline). Impedance differences between groups were significant until four years (all P < 0.05). Adverse events included thresholds over 1?V, 5 of 6 active and 2 of 5 passive leads returned to below 1?V. One active left ventricular lead dislodged. One passive left subclavian lead insulation fracture occurred. Thus Active fixation pacing leads are stable in a five-year long-term follow up. There was no difference between active and passive leads in terms of electrical performance. PMID:25563218

Liu, Lie; Tang, Jiaojiao; Peng, Hu; Wu, Shulin; Lin, Chunying; Chen, Dongli; Zhang, Qianhuan; Liang, Yuanhong; Chen, Silin; Chen, Yan; Wei, Huiqiang

2015-01-01

266

Antigen-induced bronchial anaphylaxis in actively sensitized guinea-pigs: effect of long-term treatment with sodium cromoglycate and aminophylline.  

PubMed Central

1 The effects of long-term treatment with sodium cromoglycate (SCG) and aminophylline on antigen-induced bronchoconstriction have been studied in guinea-pigs actively sensitized according to two different regimens (one producing IgE- and IgG-like antibodies and the other producing exclusively IgG-like antibodies). 2 Treatment for three weeks with SCG (10 mg/kg) and aminophylline (10, 30 or 60 mg/kg) led to a decreased bronchial response capacity which persisted even three days after treatment ceased. In this respect SCG was effective only in guinea-pigs sensitized to produce at least partly IgE-like antibodies; aminophylline was effective in guinea-pigs sensitized to produce both IgE and/or IgG antibodies. 3 The results in vivo with SCG were reflected in vitro by a reduced capacity of chopped lung tissue to release histamine at antigen challenge; lungs from animals treated with aminophylline did not show reduced histamine releasing capacity. 4 Acute treatment with atropine was shown to reduce significantly the antigen-induced bronchial contraction in guinea-pigs sensitized to produce both IgE- and IgG-antibodies. No effect of atropine was seen on an IgG-mediated anaphylaxis. 5 Increased reactivity to methacholine but not to histamine was seen in guinea-pigs sensitized to produce both IgG- and IgE-antibodies. Long-term treatment with SCG did not affect this hyperreactivity to methacholine. 6 Decreased reactivity to isoprenaline was found in isolated tracheae taken from guinea-pigs sensitized to produce both IgE- and IgG-like antibodies compared to unsensitized guinea-pigs. Long-term treatment with SCG, but not with aminophylline, reversed this decreased reactivity. PMID:6170376

Andersson, P.; Bergstrand, H.

1981-01-01

267

Long-term Outcomes of the FRESH START Trial: Exploring the Role of Self-efficacy in Cancer Survivors’ Maintenance of Dietary Practices and Physical Activity  

PubMed Central

Objective This study examined whether changes in self-efficacy explain the effects of a mailed print intervention on long-term dietary practices of breast and prostate cancer survivors. The relationship between change in self-efficacy and long-term physical activity (PA) also was examined. Methods Breast and prostate cancer survivors (N=543) from 39 U.S. states and two Canadian provinces participated in the FRESH START intervention trial. Participants were randomly assigned to receive a 10-month program of mailed print materials on diet and PA available in the public domain or a 10-month program of tailored materials designed to increase fruit and vegetable (F&V) intake, decrease fat intake, and/or increase PA. Changes in self-efficacy for F&V intake and fat restriction were analyzed as potential mediators of the intervention’s effects on diet at 2-year follow-up. Because we previously found that change in self-efficacy for PA did not vary by group assignment, the relationship between change in self-efficacy and PA at 2-year follow-up was examined across study conditions. Results Results suggest that change in self-efficacy for fat restriction partially explained the intervention’s effect on fat intake (mean indirect effect=-.28), and change in self-efficacy for F&V consumption partially explained the intervention’s effect on daily F&V intake (mean indirect effect=.11). Change in self-efficacy for fat restriction partially accounted for the intervention’s impact on overall diet quality among men only (mean indirect effect=.60). Finally, change in self-efficacy for PA predicted PA at 2-year follow-up. Conclusions Findings suggest that self-efficacy may influence long-term maintenance of healthy lifestyle practices among cancer survivors. PMID:22544562

Mosher, Catherine E.; Lipkus, Isaac; Sloane, Richard; Snyder, Denise C.; Lobach, David F.; Demark-Wahnefried, Wendy

2012-01-01

268

Early Presymptomatic and Long-Term Changes of Rest Activity Cycles and Cognitive Behavior in a MPTP-Monkey Model of Parkinson's Disease  

PubMed Central

Background It is increasingly recognized that non-motor symptoms are a prominent feature of Parkinson's disease and in the case of cognitive deficits can precede onset of the characteristic motor symptoms. Here, we examine in 4 monkeys chronically treated with low doses of the neurotoxin MPTP the early and long-term alterations of rest-activity rhythms in relationship to the appearance of motor and cognitive symptoms. Methodology/Principal Findings Behavioral activity recordings as well as motor and cognitive assessments were carried out continuously and in parallel before, during and for several months following MPTP-treatment (12–56 weeks). Cognitive abilities were assessed using a task that is dependent on the functional integrity of the fronto-striatal axis. Rest-activity cycles were monitored continuously using infrared movement detectors of locomotor activity. Motor impairment was evaluated using standardized scales for primates. Results show that MPTP treatment led to an immediate alteration (within one week) of rest-activity cycles and cognitive deficits. Parkinsonian motor deficits only became apparent 3 to 5 weeks after initiating chronic MPTP administration. In three of the four animals studied, clinical scores returned to control levels 5–7 weeks following cessation of MPTP treatment. In contrast, both cognitive deficits and chronobiological alterations persisted for many months. Levodopa treatment led to an improvement of cognitive performance but did not affect rest-activity rhythms in the two cases tested. Conclusions/Significance Present results show that i) changes in the rest activity cycles constituted early detectable consequences of MPTP treatment and, along with cognitive alterations, characterize the presymptomatic stage; ii) following motor recovery there is a long-term persistence of non-motor symptoms that could reflect differential underlying compensatory mechanisms in these domains; iii) the progressive MPTP-monkey model of presymptomatic ongoing parkinsonism offers possibilities for in-depth studies of early non-motor symptoms including sleep alterations and cognitive deficits. PMID:21887350

Vezoli, Julien; Fifel, Karim; Leviel, Vincent; Dehay, Colette; Kennedy, Henry; Cooper, Howard M.; Gronfier, Claude; Procyk, Emmanuel

2011-01-01

269

TISSUE-PLASMINOGEN ACTIVATOR IS INDUCED AS AN IMMEDIATE-EARLY GENE DURING SEIZURE, KINDLING, AND LONG-TERM POTENTIATION  

EPA Science Inventory

Activity-dependent genes in brain have been identified using differential screening of hippocampal cDNA library from rats exposed to metrazol seizures under conditions of superconduction. Five immediate early genes whose expression is elevated by neural activity were identified. ...

270

Long-term behaviour of starspots. III - Active longitudes on the long-period RS CVn star HK Lacertae  

NASA Technical Reports Server (NTRS)

Thirteen years of photometry were used to study active longitudes on the surface of HK Lacertae. The decaying and forming phenomena of active areas in the years of 1980-1981, 1983-1984, and 1988-1989 are shown. New activity centers suddenly occur near the same orbital phase (0.6) and have lifetimes of several (greater than 6) years. The average rotational period of HK Lac is 24.2852 d; compared to the orbital period of 24.4284 d, this implies a 32 degree/year drift of the active areas on the stellar surface. Two possible interpretations for the period difference are discussed: pseudosynchronism and rigidity of magnetic patterns. The active longitudes on HK Lac are compared with similar phenomena found on the sun.

Olah, K.; Hall, D. S.; Henry, G. W.

1991-01-01

271

Relative desirability of leisure activities and work parameters in a simulation of isolated work stations. [long term space flight simulation  

NASA Technical Reports Server (NTRS)

The kinds of activities that are attractive to man in long duration isolation are delineated considering meaningful work as major activity and a choice of leisure/living provisions. The dependent variables are the relative distribution between various work, leisure, and living activities where external constraints on the subject's freedom of choice are minimized. Results indicate that an average of at least five hours per day of significant meaningful work is required for satisfactory enjoyment of the situation; most other parameters of the situation have less effects on overall performance and satisfaction

Sullins, W. R., Jr.; Rogers, J. G.

1974-01-01

272

Simultaneous Monitoring of Presynaptic Transmitter Release and Postsynaptic Receptor Trafficking Reveals an Enhancement of Presynaptic Activity in Metabotropic Glutamate Receptor-Mediated Long-Term Depression  

PubMed Central

Although the contribution of postsynaptic mechanisms to long-term synaptic plasticity has been studied extensively, understanding the contribution of presynaptic modifications to this process lags behind, primarily because of a lack of techniques with which to directly and quantifiably measure neurotransmitter release from synaptic terminals. Here, we developed a method to measure presynaptic activity through the biotinylation of vesicular transporters in vesicles fused with presynaptic membranes during neurotransmitter release. This method allowed us for the first time to selectively quantify the spontaneous or evoked release of glutamate or GABA at their respective synapses. Using this method to investigate presynaptic changes during the expression of group I metabotropic glutamate receptor (mGluR1/5)-mediated long-term depression (LTD) in cultured rat hippocampal neurons, we discovered that this form of LTD was associated with increased presynaptic release of glutamate, despite reduced miniature EPSCs measured with whole-cell recording. Moreover, we found that specific blockade of AMPA receptor (AMPAR) endocytosis with a membrane-permeable GluR2-derived peptide not only prevented the expression of LTD but also eliminated LTD-associated increase in presynaptic release. Thus, our work not only demonstrates that mGluR1/5-mediated LTD is associated with increased endocytosis of postsynaptic AMPARs but also reveals an unexpected homeostatic/compensatory increase in presynaptic release. In addition, this study indicates that biotinylation of vesicular transporters in live cultured neurons is a valuable tool for studying presynaptic function. PMID:23536098

Dobie, Frederick A.; Baudry, Michel; Craig, Ann Marie; Wong, Tak Pan; Wang, Yu Tian

2014-01-01

273

Chronic, long-term social stress can cause decreased microtubule protein network activity and dynamics in cerebral cortex of male wistar rats.  

PubMed

Social stress is viewed as a factor in the etiology of a variety of psychopathologies such as depression and anxiety. Animal models of social stress are well developed and widely used in studying clinical and physiological effects of stress. Stress is known to significantly affect learning and memory, and this effect strongly depends on the type of stress, its intensity, and duration. It has been demonstrated that chronic and acute stress conditions can change neuronal plasticity, characterized by retraction of apical dendrites, reduction in axonogenesis, and decreased neurogenesis. Various behavioral studies have also confirmed a decrease in learning and memory upon exposure of animals to long-term chronic stress. On the other hand, the close relationship between microtubule (MT) protein network and neuroplasticity controlling system suggests the possibility of MT protein alterations in high stressful conditions. In this work, we have studied the kinetics, activity, and dynamicity changes of MT proteins in the cerebral cortex of male Wistar rats that were subjected to social instability for 35 and 100 days. Our results indicate that MT protein network dynamicity and polymerization ability is decreased under long-term (100 days) social stress conditions. PMID:25106479

Eskandari Sedighi, Ghazaleh; Riazi, Gholam Hossein; Vaez Mahdavi, Mohammad Reza; Cheraghi, Tayebe; Atarod, Deyhim; Rafiei, Shahrbanoo

2015-03-01

274

Effects of paraoxonase 1 activity and gene polymorphisms on long-term pulmonary complications of sulfur mustard-exposed veterans.  

PubMed

Sulfur mustard (SM) is an alkylating agent with prolonged adverse effects. The antioxidant paraoxonase 1 (PON1), an endogenous free radical scavenger, plays a protective role against oxidative stress. The possible roles of oxidative stress in the pathogenesis of SM, together with the antioxidant activity of PON1, are enough to warrant the analysis of PON1 polymorphisms and allelic variants in incapacitated veterans. PON1 55 L/M and 192 Q/R polymorphisms were assayed in 289 male veterans with severe pulmonary conditions, who were exposed to SM 20-25 years ago, and 66 gender-, age- and ethnic-matched healthy controls. As we showed previously the PON1 activity decreased significantly in veterans. However, PON1 55 L/M and 192 Q/R genotype distributions were not significantly different between the veterans and the controls. R and L allele carriers have also significantly higher basal and salt-stimulated PON1 activity than Q and M allele carriers. Paraoxonase and arylesterase activities in individuals with the QQ+(MM or LM) genotype were significantly lower than those with the (RR or QR)+LL genotype. Furthermore, basal and salt-stimulated paraoxonase activity in veterans with the (RR or QR)+LL genotype was significantly lower than that in the controls. A positive correlation has been determined between serum PON1 activity and pulmonary function test in QR/LL genotypes. Some of the veterans with RR+QR genotypes have also shown a novel missense change of Asn227Ser in exon 6 of the enzyme. This substitution is close to the binding domain of PON1 and so modifies enzyme activity. PMID:23370296

Taravati, Ali; Ardestani, Sussan K; Ziaee, Abed-Ali; Ghorbani, Atefeh; Soroush, Mohammad-Reza; Faghihzadeh, Soghrat; Kazemi, Hadi; Rezaei, Abbas; Hoseini, Habibollah; Ghazanfari, Tooba

2013-11-01

275

Solar activity secular cycles  

NASA Astrophysics Data System (ADS)

Long-term variations in solar activity secular cycles have been studied using a method for the expansion of reconstructed sunspot number series Sn( t) for 11400 years in terms of natural orthogonal functions. It has been established that three expansion components describe more than 98% of all Sn( t) variations. In this case, the contribution of the first expansion component is about 92%. The averaged form of the 88year secular cycle has been determined based on the form of the first expansion coordinate function. The quasi-periodicities modulating the secular cycle have been revealed based on the time function conjugate to the first function. The quasi-periodicities modulating the secular cycle coincide with those observed in the Sn( t) series spectrum. A change in the secular cycle form and the time variations in this form are described by the second and third expansion components, the contributions of which are about 4 and 2%, respectively. The variations in the steepness of the secular cycle branches are more pronounced in the 200-year cycle, and the secular cycle amplitude varies more evidently in the 2300-year cycle.

Kramynin, A. P.; Mordvinov, A. V.

2013-12-01

276

Antioxidant activity in mature branches of ponderosa pine (Pinus ponderosa) under long-term, low concentration ozone exposure  

SciTech Connect

Antioxidant activity (superoxide dismutase, peroxidases and glutathione) is being examined in mature needle tissue of ponderosa pine exposed to elevated levels of ozone (O{sub 3}). Trees used in this study are 8-14 year-old clones produced from buds from a 70 year-old tree grafted onto seedling rootstock. Trees are exposed to O{sub 3} using a newly developed branch exposure chamber (BEC). Ozone treatments are charcoal-filtered, ambient and 2x ambient concentrations. A non-chambered branch will determine the effect of exposure chamber. Superoxide dismutase (SOD) activity measured in current-year needles in February via nitrobluetetrazolium (NBT) reduction was 138.5 {plus minus} 15 (SD) units mg{sup {minus}1} protein. The activity of guaiacol-oxidizing peroxidases was 89 {plus minus} 19 (SD) {Delta}A{sub 470} min{sup {minus}1} mg{sup {minus}1} protein. Ascorbate peroxidase and the ratio of oxidized to reduced glutathione (GSSG/GSH) are also being monitored. Antioxidant activity will be measured monthly across the ozone season (March to November) and during natural ozone episodes. Cellular antioxidant activity will be related to needle photosynthesis, respiration and stomatal conductance measured using a Licor 6200 portable photosynthesis apparatus.

Benes, S.E.; Murphy, T.M.; Laeuchli, A. (Univ. of California, Davis (USA)); Anderson, P.D.; Houpis, J.L.J. (Lawrence Livermore National Laboratory, CA (USA))

1990-05-01

277

Long-term effects of rapamycin treatment on insulin mediated phosphorylation of Akt/PKB and glycogen synthase activity  

SciTech Connect

Protein kinase B (Akt/PKB) is a Ser/Thr kinase that is involved in the regulation of cell proliferation/survival through mammalian target of rapamycin (mTOR) and the regulation of glycogen metabolism through glycogen synthase kinase 3{beta} (GSK-3{beta}) and glycogen synthase (GS). Rapamycin is an inhibitor of mTOR. The objective of this study was to investigate the effects of rapamycin pretreatment on the insulin mediated phosphorylation of Akt/PKB phosphorylation and GS activity in parental HepG2 and HepG2 cells with overexpression of constitutively active Akt1/PKB-{alpha} (HepG2-CA-Akt/PKB). Rapamycin pretreatment resulted in a decrease (20-30%) in the insulin mediated phosphorylation of Akt1 (Ser 473) in parental HepG2 cells but showed an upregulation of phosphorylation in HepG2-CA-Akt/PKB cells. Rictor levels were decreased (20-50%) in parental HepG2 cells but were not significantly altered in the HepG2-CA-Akt/PKB cells. Furthermore, rictor knockdown decreased the phosphorylation of Akt (Ser 473) by 40-60% upon rapamycin pretreatment. GS activity followed similar trends as that of phosphorylated Akt and so with rictor levels in these cells pretreated with rapamycin; parental HepG2 cells showed a decrease in GS activity, whereas as HepG2-CA-Akt/PKB cells showed an increase in GS activity. The changes in the levels of phosphorylated Akt/PKB (Ser 473) correlated with GS and protein phoshatase-1 activity.

Varma, Shailly [Department of Biochemistry, College of Medicine, University of Saskatchewan, Saskatoon, SK S7N 5E5 (Canada); Shrivastav, Anuraag [Department of Pathology and Laboratory Medicine, College of Medicine, University of Saskatchewan, Saskatoon, SK S7N 5E5 (Canada); Health Research Division, Saskatchewan Cancer Agency, Saskatoon, SK S7N 4H4 (Canada); Changela, Sheena [Department of Biochemistry, College of Medicine, University of Saskatchewan, Saskatoon, SK S7N 5E5 (Canada); Khandelwal, Ramji L. [Department of Biochemistry, College of Medicine, University of Saskatchewan, Saskatoon, SK S7N 5E5 (Canada)], E-mail: ramji.khandelwal@usask.ca

2008-04-01

278

Choline acetyltransferase activity in the hamster central auditory system and long-term effects of intense tone exposure.  

PubMed

Acoustic trauma often leads to loss of hearing of environmental sounds, tinnitus, in which a monotonous sound not actually present is heard, and/or hyperacusis, in which there is an abnormal sensitivity to sound. Research on hamsters has documented physiological effects of exposure to intense tones, including increased spontaneous neural activity in the dorsal cochlear nucleus. Such physiological changes should be accompanied by chemical changes, and those chemical changes associated with chronic effects should be present at long times after the intense sound exposure. Using a microdissection mapping procedure combined with a radiometric microassay, we have measured activities of choline acetyltransferase (ChAT), the enzyme responsible for synthesis of the neurotransmitter acetylcholine, in the cochlear nucleus, superior olive, inferior colliculus, and auditory cortex of hamsters 5 months after exposure to an intense tone compared with control hamsters of the same age. In control hamsters, ChAT activities in auditory regions were never more than one-tenth of the ChAT activity in the facial nerve root, a bundle of myelinated cholinergic axons, in agreement with a modulatory rather than a dominant role of acetylcholine in hearing. Within auditory regions, relatively higher activities were found in granular regions of the cochlear nucleus, dorsal parts of the superior olive, and auditory cortex. In intense-tone-exposed hamsters, ChAT activities were significantly increased in the anteroventral cochlear nucleus granular region and the lateral superior olivary nucleus. This is consistent with some chronic upregulation of the cholinergic olivocochlear system influence on the cochlear nucleus after acoustic trauma. PMID:23605746

Godfrey, Donald A; Kaltenbach, James A; Chen, Kejian; Ilyas, Omer

2013-07-01

279

BACTERIAL ACTIVITY, COMMUNITY STRUCTURE, AND DEGREE OF SPATIAL HEREROGENEITY ON THE SMALL SCALE AT A LONG-TERM CONTAMINATED SITE  

Technology Transfer Automated Retrieval System (TEKTRAN)

In an anthropogenically disturbed soil, (88% sand, 8% silt, 4% clay) 150 mg samples were studied to examine the fine scale relationship of bacterial activity and community structure to heavy metal contaminants. The soils had been contaminated for over 40 years with aromatic solvents, lead (Pb), and...

280

Long term effects of salt on activity, population structure and floc characteristics in enriched bacterial cultures of nitrifiers.  

PubMed

The effect of salinity on the activity, the composition of nitrifiers and floc characteristics of nitrifying sludge was studied. Non-adapted and adapted (to 10g NaCl-Cl(-)/L for one year) enriched cultures of nitrifiers were tested in three sequencing batch reactors. Salt was increased gradually with 5 up to 40 g Cl(-)/L. No difference in steady state activity was observed between the adapted and non-adapted sludge. The activities of ammonia and nitrite oxidizers dropped 36% and 11%, respectively, at salt concentrations of 10 g Cl(-)/L. At 40 g Cl(-)/L inhibition reached 95% of salt free activity for ammonia and nitrite oxidizers in both adapted and non-adapted reactors. Nitrosomonas europaea and Nitrobacter sp. (fluorescent in situ hybridization) were the only nitrifiers present at high salt levels. Increased salt concentrations resulted in better settling characteristics of the nitrifying sludge. After 118 days the sludge was brought back to the initial conditions (0 g Cl(-)/L for non-adapted and 10 g Cl(-)/L for adapted). Despite the change in population composition similar kinetics as before the salt stress were observed. PMID:16530803

Moussa, M S; Sumanasekera, D U; Ibrahim, S H; Lubberding, H J; Hooijmans, C M; Gijzen, H J; van Loosdrecht, M C M

2006-04-01

281

The Effect of Long-Term Storage on the Physiochemical and Bactericidal Properties of Electrochemically Activated Solutions  

PubMed Central

Electrochemically activated solutions (ECAS) are generated by electrolysis of NaCl solutions, and demonstrate broad spectrum antimicrobial activity and high environmental compatibility. The biocidal efficacy of ECAS at the point of production is widely reported in the literature, as are its credentials as a “green biocide.” Acidic ECAS are considered most effective as biocides at the point of production and ill suited for extended storage. Acidic ECAS samples were stored at 4 °C and 20 °C in glass and polystyrene containers for 398 days, and tested for free chlorine, pH, ORP and bactericidal activity throughout. ORP and free chlorine (mg/L) in stored ECAS declined over time, declining at the fastest rate when stored at 20 °C in polystyrene and at the slowest rate when stored at 4 °C in glass. Bactericidal efficacy was also affected by storage and ECAS failed to produce a 5 log10 reduction on five occasions when stored at 20 °C. pH remained stable throughout the storage period. This study represents the longest storage evaluation of the physiochemical parameters and bactericidal efficacy of acidic ECAS within the published literature and reveals that acidic ECAS retain useful bactericidal activity for in excess of 12 months, widening potential applications. PMID:23263673

Robinson, Gareth; Thorn, Robin; Reynolds, Darren

2013-01-01

282

Long-term monitoring of soil microbiological activities in two forest sites in South tyrol in the italian alps.  

PubMed

We monitored microbiological properties in two forest sites over a period of 17 years (1993-2010) within the International Cooperative Programme on Integrated Monitoring of Air Pollution Effects on Ecosystems (ICP IM). The two study sites were located in South Tyrol in the Italian Alps at altitudes of 1,737 m a.s.l. (subalpine site IT01) and 570 m a.s.l. (submontane site IT02). Soil samples were collected in the late spring and autumn of 1993, 2000, and 2010, and were characterized by measuring respiration, key enzyme activities involved in the C, N, P, and S cycles and litter degradation, and the abundance of viable bacterial and fungal populations. Over the study period, an increase in mean annual air temperatures at both sites (+0.6°C and +0.8°C at IT01 and IT02, respectively) was calculated from trendlines. Significantly lower mean annual air temperatures, higher temperature fluctuations, and higher annual precipitation rates were observed at site IT01 than at site IT02. Subalpine site IT01 was characterized by significantly lower microbial activity (respiration, enzymes) and abundance than those at submontane site IT02. The year of sampling had a significant effect on all the parameters investigated, except for nitrification. Fungal abundance decreased consistently over the study period, while no consistent trend was noted among the other parameters investigated. Season only affected a few of the measured microbiological parameters: respiration and bacterial numbers were significantly higher in the spring than in the autumn, while the opposite was noted for xylanase and phosphatase activities. Soil fungi contributed essentially to xylanase and protease activities, while soil bacteria were mainly involved in degradation processes that required the activity of sulfatase. PMID:25008018

Margesin, Rosa; Minerbi, Stefano; Schinner, Franz

2014-09-17

283

Geomagnetic activity: Dependence on solar wind parameters  

NASA Technical Reports Server (NTRS)

Current ideas about the interaction between the solar wind and the earth's magnetosphere are reviewed. The solar wind dynamic pressure as well as the influx of interplanetary magnetic field lines are both important for the generation of geomagnetic activity. The influence of the geometry of the situation as well as the variability of the interplanetary magnetic field are both found to be important factors. Semi-annual and universal time variations are discussed as well as the 22-year cycle in geomagnetic activity. All three are found to be explainable by the varying geometry of the interaction. Long term changes in geomagnetic activity are examined.

Svalgaard, L.

1977-01-01

284

Long-term characterization, lagoon treatment and migration potential of landfill leachate: a case study in an active Italian landfill  

Microsoft Academic Search

The elaboration of 10 years of monitoring of leachate quality and quantity, leachate treatment and degree of contamination of soil and surface waters at the Tre Monti site––an active, 4-million-m3 landfill in Northern Italy––is presented in this study. A hydrological model of leachate production is applied, with a good match of the experimental data. The concentrations of all leachate components

D Frascari; F Bronzini; G Giordano; G Tedioli; M Nocentini

2004-01-01

285

Soil microbial activity, nitrogen cycling, and long-term changes in organic carbon pools as related to fallow tillage management  

Microsoft Academic Search

Two experiments were established in 1969 and 1970 near Sidney, NE, to determine the effect of moldboard plow (plow), sub-tillage (sub-till), and no-tillage (no-till) fallow management on soil properties, biological activities, and carbon and nitrogen cycling. One experiment was on land which had been broken from sod in 1920, seeded to crested wheatgrass [Agropyron cristatum (L.) Gaertn.] from 1957 to

J. W Doran; E. T Elliott; K Paustian

1998-01-01

286

Interaction Between Pain, Movement, and Physical Activity: Short-term Benefits, Long-term Consequences, and Targets for Treatment.  

PubMed

Movement is changed in pain. This presents across a spectrum from subtle changes in the manner in which a task is completed to complete avoidance of a function and could be both a cause and effect of pain/nociceptive input and/or injury. Movement, in a variety of forms, is also recommended as a component of treatment to aid the recovery in many pain syndromes. Some argue it may not be sufficient to simply increase activity, whereas others defend a necessity to consider how a person moves. There is unlikely to be a simple relationship between pain and movement, as both too little and too much movement could be suboptimal for the health of the tissues. The interaction between pain, (re)injury, and movement is surprisingly unclear. Traditional theories to explain adaptation in the motor system in pain are unable to account for the variability observed in laboratory and clinical practice. New theories are required. Treatments that focus on physical activity and exercise are the cornerstone of management of many pain conditions, but the effect sizes are modest. There is limited consensus when, if, and how interventions may be individualized and combined. The aim of this narrative review was to present current understanding of the interaction between movement and pain; as a cause or effect of pain, and in terms of the role of movement (physical activity and exercise) in recovery of pain and restoration of function. PMID:24709625

Hodges, Paul W; Smeets, Rob J

2015-02-01

287

Long-term environmental stewardship.  

SciTech Connect

The purpose of this Supplemental Information Source Document is to effectively describe Long-Term Environmental Stewardship (LTES) at Sandia National Laboratories/New Mexico (SNL/NM). More specifically, this document describes the LTES and Long-Term Stewardship (LTS) Programs, distinguishes between the LTES and LTS Programs, and summarizes the current status of the Environmental Restoration (ER) Project.

Nagy, Michael David

2010-08-01

288

Sustainability of the Catalytic Activity of a Silica-Titania Composite (STC) for Long-Term Indoor Air Quality Control  

NASA Technical Reports Server (NTRS)

TiO2-assisted photocatalytic oxidation (PCO) is an emerging technology for indoor air quality control and is also being evaluated as an alternative trace contaminant control technology for crew habitats in space exploration. Though there exists a vast range of literature on the development of photocatalysts and associated reactor systems, including catalyst performance and performance-influencing factors, the critical question of whether photocatalysts can sustain their initial catalytic activity over an extended period of operation has not been adequately addressed. For a catalyst to effectively serve as an air quality control product, it must be rugged enough to withstand exposure to a multitude of low concentration volatile organic compounds (VOCs) over long periods of time with minimal loss of activity. The objective of this study was to determine the functional lifetime of a promising photocatalyst - the silica-titania composite (STC) from Sol Gel Solutions, LLC in a real-world scenario. A bench-scale STC-packed annular reactor under continuous irradiation by a UV-A fluorescent black-light blue lamp ((lambda)max = 365 nm) was exposed to laboratory air continuously at an apparent contact time of 0.27 sand challenged with a known concentration of ethanol periodically to assess any changes in catalytic activity. Laboratory air was also episodically spiked with halocarbons (e.g., octafluoropropane), organosulfur compounds (e.g., sulfur hexafluoride), and organosilicons (e.g., siloxanes) to simulate accidental releases or leaks of such VOCs. Total organic carbon (TOC) loading and contaminant profiles of the laboratory air were also monitored. Changes in STC photocatalytic performance were evaluated using the ethanol mineralization rate, mineralization efficiency, and oxidation intermediate (acetaldehyde) formation. Results provide insights to any potential catalyst poisoning by trace halocarbons and organosulfur compounds.

Coutts, Janelle L.; Levine, Lanfang H.; Richards, Jeffrey T.

2011-01-01

289

The effects of long-term malathion or diazinon ingestion on the activity of hepatic synthesized clotting factors.  

PubMed

Female Sprague-Dawley rats were placed on a drinking solution of 1 ppm Diazinon or malathion dissolved in water for 6 months. At the conclusion of the experiment liver tissue and plasma were examined. Clotting studies included the prothrombin time (PT), partial thromboplastin time (APTT), fibrinogen, and factors II, V, VII, X, plus the platelet count. Hepatic morphology, basically hepatocyte degeneration, was altered by malathion while diazinon had no notable effect. Likewise, malathion prolonged both the PT and APTT, the only changes in clotting activity. PMID:6662056

Lox, C D; Davis, J R

1983-12-01

290

Early Activation of the Kynurenine Pathway Predicts Early Death and Long?term Outcome in Patients Resuscitated From Out?of?Hospital Cardiac Arrest  

PubMed Central

Background The kynurenine pathway (KP) is the major route of tryptophan (TRP) catabolism and is activated by inflammation and after cardiac arrest in animals. We hypothesized that the KP activation level correlates with severity of post–cardiac arrest shock, early death, and long?term outcome. Methods and Results Plasma was obtained from 245 patients enrolled in a prospective multicenter observational study in 21 intensive care units in Finland. Time to return of spontaneous circulation, lowest systolic arterial pressure, and bicarbonate during the first 24 hours were collected. A cerebral performance category of 3 to 5 defined 12?month poor outcome. Plasma TRP and KP metabolites, kynurenine (KYN), kynurenic acid, 3?hydroxyanthranilic acid, and the ratio of KYN to TRP were measured by liquid chromatography and mass spectrometry. All KP metabolites at intensive care unit admission were significantly higher in cardiac arrest patients with a nonshockable rhythm compared to those with a shockable rhythm, and kynurenic acid and 3?hydroxyanthranilic acid correlated with time to return of spontaneous circulation. Patients with higher levels of KYN, KYN to TRP, kynurenic acid, and 3?hydroxyanthranilic acid had lower 24?hour systolic arterial pressure and bicarbonate. All KP metabolites and the ratio of KYN to TRP, but not TRP, were significantly higher in patients who died in the intensive care unit in comparison to those who survived. Multivariable logistic regression showed that high kynurenic acid (odds ratio: 1.004; 95% confidence interval: 1.001 to 1.008; P=0.014), and 3?hydroxyanthranilic acid (odds ratio: 1.011; 95% confidence interval: 1.001 to 1.022; P=0.03) were independently associated with 12?month poor outcome and significantly improved risk reclassification. Conclusions KP is activated early after cardiac arrest and is associated with severity of post–cardiac arrest shock, early death, and poor long?term outcome. PMID:25092787

Ristagno, Giuseppe; Latini, Roberto; Vaahersalo, Jukka; Masson, Serge; Kurola, Jouni; Varpula, Tero; Lucchetti, Jacopo; Fracasso, Claudia; Guiso, Giovanna; Montanelli, Alessandro; Barlera, Simona; Gobbi, Marco; Tiainen, Marjaana; Pettilä, Ville; Skrifvars, Markus B.

2014-01-01

291

Optimal warm-up stimuli of muscle activation to enhance short and long-term acute jumping performance.  

PubMed

The aim of this study was to determine the effect of different types of active warm-up stimuli of muscle activation on explosive jumping performance after short (5 min postwarm-up) and long (6 h postwarm-up) recovery periods following warm-up. Twelve trained volleyball players (21-24 years) performed different types of specific warm-up stimuli (WP) after baseline measurements [e.g., countermovement jump (CMJ) without and with extra load and Drop jump (DJ)] on randomized separate occasions: (1) three sets of five jumps with extra load (WP1), (2) two sets of four reps at 80% of 1RM parallel squat (1RM(PS)) and two sets of two reps at 85% of 1RM(PS) (WP2), (3) two sets of four reps at 80% of 1RM(PS) and two sets of two reps at 90% of 1RM(PS) and two sets of one rep at 95% of 1RM(PS) (WP3), (4) three sets of five DJs (WP4), (5) specified warm-up for a volleyball match (WP5), (6) three sets of five reps at 30% 1RM(PS) (WP6), and (7) an experimental condition of no active warm-up. Height in DJ significantly improved (P < 0.05) after WP1 (4.18%), WP2 (2.98%), WP3 (5.47%), and WP5 (4.49%). Maximal power output during CMJ with extra load significantly improved (P < 0.05) after WP2 (11.39%), WP5 (10.90%), WP3 (9%), and WP1 (2.47%). High-intensity dynamic loading (e.g., 80-95% 1RM), as well as specific volleyball warm-up protocol bring about the greatest effects on subsequent neuromuscular explosive responses. Acute positive effects on jumping performance after warm-up were maintained after long recovery periods (e.g., 6 h following warm-up), particularly when prior high-intensity dynamic actions were performed. PMID:17394010

Saez Saez de Villarreal, Eduardo; González-Badillo, Juan J; Izquierdo, Mikel

2007-07-01

292

Study of long term radon transport by measuring the difference of the 210Pb and 226Ra activity in soil as a function of the depth.  

PubMed

Long term radon transport has been studied by measuring the activity difference of 210Pb and 226Ra in soil as a function of the depth. The results are from test pits of 1-2 m depth made at a dam of a tailings pond and at the plateau of a waste rock pile. Soil samples of about 1 kg were taken at a successive distances of 5 cm and analyzed by means of gamma-ray spectroscopy using low background germanium n-type detectors. It is shown that by this method nearly model independent information about the radon transport over a period of several decades can be inferred from the data. PMID:12553654

Schulz, H; Funke, L; Schellenberger, A

2003-02-01

293

Lytic activity by temperate phages of Pseudomonas aeruginosa in long-term cystic fibrosis chronic lung infections.  

PubMed

Pseudomonas aeruginosa is the most common bacterial pathogen infecting the lungs of cystic fibrosis (CF) patients. The transmissible Liverpool epidemic strain (LES) harbours multiple inducible prophages (LES?2; LES?3; LES?4; LES?5; and LES?6), some of which are known to confer a competitive advantage in an in vivo rat model of chronic lung infection. We used quantitative PCR (Q-PCR) to measure the density and dynamics of all five LES phages in the sputa of 10 LES-infected CF patients over a period of 2 years. In all patients, the densities of free-LES phages were positively correlated with the densities of P. aeruginosa, and total free-phage densities consistently exceeded bacterial host densities 10-100-fold. Further, we observed a negative correlation between the phage-to-bacterium ratio and bacterial density, suggesting a role for lysis by temperate phages in regulation of the bacterial population densities. In 9/10 patients, LES?2 and LES?4 were the most abundant free phages, which reflects the differential in vitro induction properties of the phages. These data indicate that temperate phages of P. aeruginosa retain lytic activity after prolonged periods of chronic infection in the CF lung, and suggest that temperate phage lysis may contribute to regulation of P. aeruginosa density in vivo.The ISME Journal advance online publication, 2 December 2014; doi:10.1038/ismej.2014.223. PMID:25461970

James, Chloe E; Davies, Emily V; Fothergill, Joanne L; Walshaw, Martin J; Beale, Colin M; Brockhurst, Michael A; Winstanley, Craig

2014-12-01

294

Long-term deforestation in NW Spain: linking the Holocene fire history to vegetation change and human activities  

NASA Astrophysics Data System (ADS)

The Holocene fire regime is thought to have had a key role in deforestation and shrubland expansion in Galicia (NW Spain) but the contribution of past societies to vegetation burning remains poorly understood. This may be, in part, due to the fact that detailed fire records from areas in close proximity to archaeological sites are scarce. To fill this gap, we performed charcoal analysis in five colluvial soils from an archaeological area (Campo Lameiro) and compared the results to earlier studies from this area and palaeo-ecological literature from NW Spain. This analysis allowed for the reconstruction of the vegetation and fire dynamics in the area during the last ca 11 000 yrs. In the Early Holocene, Fabaceae and Betula sp. were dominant in the charcoal record. Quercus sp. started to replace these species around 10 000 cal BP, forming a deciduous forest that prevailed during the Holocene Thermal Maximum until ?5500 cal BP. Following that, several cycles of potentially fire-induced forest regression with subsequent incomplete recovery eventually led to the formation of an open landscape dominated by shrubs (Erica sp. and Fabaceae). Major episodes of forest regression were (1) ?5500-5000 cal BP, which marks the mid-Holocene cooling after the Holocene Thermal Maximum, but also the period during which agropastoral activities in NW Spain became widespread, and (2) ?2000-1500 cal BP, which corresponds roughly to the end of the Roman Warm Period and the transition from the Roman to the Germanic period. The low degree of chronological precision, which is inherent in fire history reconstructions from colluvial soils, made it impossible to distinguish climatic from human-induced fires. Nonetheless, the abundance of synanthropic pollen indicators (e.g. Plantago lanceolata and Urtica dioica) since at least ?6000 cal BP strongly suggests that humans used fire to generate and maintain pasture.

Kaal, Joeri; Carrión Marco, Yolanda; Asouti, Eleni; Martín Seijo, Maria; Martínez Cortizas, Antonio; Costa Casáis, Manuela; Criado Boado, Felipe

2011-01-01

295

Relationship between the photosynthetic activity and the performance of Cakile maritima after long-term salt treatment.  

PubMed

Cakile maritima is a halophyte with potential for ecological, economical and medicinal uses. We address here the impact of salinity on its growth, photosynthesis and seed quality. Whole plant growth rate and shoot development were stimulated at moderate salinity (100-200 mM NaCl) and inhibited at higher salt concentrations. Although diminished in the presence of salt, potassium and calcium uptake per unit of root biomass was maintained at relatively high value, while nutrient-use efficiency (NUE) was improved in salt-treated plants. Chl and carotenoid concentrations decreased at extreme salinities, but anthocyanin concentration continuously grew with salinity. Net photosynthetic rate (A), stomatal conductance, maximum quantum efficiency of PSII and quantum yield were stimulated in the 100-200 mM NaCl range. Higher salinity adversely affected gas exchange and changed PSII functional characteristics, resulting in a reduction of A per leaf area unit. This phenomenon was associated with increased non-photochemical quenching. Harvest index, silique number and seeds per fruit valve were maximal at 100 mM NaCl. Despite the decreasing salt accumulation gradient from the vegetative to the reproductive organs, high salinities were detrimental for the seed viability and increased the proportion of empty siliques. Overall, the salt-induced changes in the plant photosynthetic activity resulted into analogous responses at the vegetative and reproductive stages. The enhancement of NUE, the absence of pigment degradation, the reduction of water loss and the concomitant PSII protection from photodamage through thermal dissipation of excess excitation significantly accounted for Cakile survival capacity at high salinity. PMID:18346075

Debez, Ahmed; Koyro, Hans-Werner; Grignon, Claude; Abdelly, Chedly; Huchzermeyer, Bernhard

2008-06-01

296

Adipose Tissue-Derived Mesenchymal Stem Cells in Long-Term Dialysis Patients Display Downregulation of PCAF Expression and Poor Angiogenesis Activation  

PubMed Central

We previously demonstrated that mesenchymal stem cells (MSCs) differentiate into functional kidney cells capable of urine and erythropoietin production, indicating that they may be used for kidney regeneration. However, the viability of MSCs from dialysis patients may be affected under uremic conditions. In this study, we isolated MSCs from the adipose tissues of end-stage kidney disease (ESKD) patients undergoing long-term dialysis (KD-MSCs; mean: 72.3 months) and from healthy controls (HC-MSCs) to compare their viability. KD-MSCs and HC-MSCs were assessed for their proliferation potential, senescence, and differentiation capacities into adipocytes, osteoblasts, and chondrocytes. Gene expression of stem cell-specific transcription factors was analyzed by PCR array and confirmed by western blot analysis at the protein level. No significant differences of proliferation potential, senescence, or differentiation capacity were observed between KD-MSCs and HC-MSCs. However, gene and protein expression of p300/CBP-associated factor (PCAF) was significantly suppressed in KD-MSCs. Because PCAF is a histone acetyltransferase that mediates regulation of hypoxia-inducible factor-1? (HIF-1?), we examined the hypoxic response in MSCs. HC-MSCs but not KD-MSCs showed upregulation of PCAF protein expression under hypoxia. Similarly, HIF-1? and vascular endothelial growth factor (VEGF) expression did not increase under hypoxia in KD-MSCs but did so in HC-MSCs. Additionally, a directed in vivo angiogenesis assay revealed a decrease in angiogenesis activation of KD-MSCs. In conclusion, long-term uremia leads to persistent and systematic downregulation of PCAF gene and protein expression and poor angiogenesis activation of MSCs from patients with ESKD. Furthermore, PCAF, HIF-1?, and VEGF expression were not upregulated by hypoxic stimulation of KD-MSCs. These results suggest that the hypoxic response may be blunted in MSCs from ESKD patients. PMID:25025381

Yamanaka, Shuichiro; Yokote, Shinya; Yamada, Akifumi; Katsuoka, Yuichi; Izuhara, Luna; Shimada, Yohta; Omura, Nobuo; Okano, Hirotaka James; Ohki, Takao; Yokoo, Takashi

2014-01-01

297

The effect of long-term nitrate treatment on SRB activity, corrosion rate and bacterial community composition in offshore water injection systems.  

PubMed

Biogenic production of hydrogen sulphide (H(2)S) is a problem for the oil industry as it leads to corrosion and reservoir souring. Continuous injection of a low nitrate concentration (0.25-0.33 mM) replaced glutaraldehyde as corrosion and souring control at the Veslefrikk and Gullfaks oil field (North Sea) in 1999. The response to nitrate treatment was a rapid reduction in number and activity of sulphate-reducing bacteria (SRB) in the water injection system biofilm at both fields. The present long-term study shows that SRB activity has remained low at < or =0.3 and < or =0.9 microg H(2)S/cm(2)/day at Veslefrikk and Gullfaks respectively, during the 7-8 years with continuous nitrate injection. At Veslefrikk, 16S rRNA gene based community analysis by PCR-DGGE showed that bacteria affiliated to nitrate-reducing sulphide-oxidizing Sulfurimonas (NR-SOB) formed major populations at the injection well head throughout the treatment period. Downstream of deaerator the presence of Sulfurimonas like bacteria was less pronounced, and were no longer observed 40 months into the treatment period. The biofilm community during nitrate treatment was highly diverse and relative stable for long periods of time. At the Gullfaks field, a reduction in corrosion of up to 40% was observed after switch to nitrate treatment. The present study show that nitrate injection may provide a stable long-term inhibition of SRB in sea water injection systems, and that corrosion may be significantly reduced when compared to traditional biocide treatment. PMID:18752014

Bødtker, Gunhild; Thorstenson, Tore; Lillebø, Bente-Lise P; Thorbjørnsen, Bente E; Ulvøen, Rikke Helen; Sunde, Egil; Torsvik, Terje

2008-12-01

298

Linking people with long-term health conditions to healthy community activities: development of Patient-Led Assessment for Network Support (PLANS)  

PubMed Central

ObjectiveTo combine insights from service users with long-term conditions (LTCs) to assist the development of a community referral intervention designed to promote engagement and improve access to health-relevant resources. BackgroundSocial deprivation and reduced access to resources have been causally linked with social isolation and the ability to manage LTCs. Participation in meaningful activity has been associated with positive health benefits, and strategies to promote access to community activities have shown some potential to improve outcomes for people with LTCs. This suggests the need to develop an engagement and referral intervention in partnership with service users and community groups as part of mainstream self-care support. MethodA series of focus groups and interviews with members of community groups in Greater Manchester designed as an iterative and collaborative approach to elicit the role of personal and community networks that support long-term condition management (LTCM) to develop a community referral tool. ResultsParticipants reported a broad range of resources relevant to LTCM that often went beyond the usual concerns associated with self-care. This helped to inform a tool (PLANS) to tailor access to types of community-based resources which can support LTCM. ConclusionsUnderstanding the everyday challenges of living with a LTC highlighted the importance of connecting and engaging with localized support for people. In response to this, we developed an intervention (PLANS) which tailors access to local resources based on personal preferences, needs and acceptability to encourage service users to engage with sustainable health choices. PMID:23731452

Blickem, Christian; Kennedy, Anne; Vassilev, Ivaylo; Morris, Rebecca; Brooks, Helen; Jariwala, Praksha; Blakeman, Tom; Rogers, Anne

2013-01-01

299

Elevated RalA activity in the hippocampus of PI3K? knock-out mice lacking NMDAR-dependent long-term depression.  

PubMed

Phosphoinositide 3-kinases (PI3Ks) play key roles in synaptic plasticity and cognitive functions in the brain. We recently found that genetic deletion of PI3K?, the only known member of class IB PI3Ks, results in impaired N-methyl-D-aspartate receptor-dependent long-term depression (NMDAR-LTD) in the hippocampus. The activity of RalA, a small GTP-binding protein, increases following NMDAR-LTD inducing stimuli, and this increase in RalA activity is essential for inducing NMDAR-LTD. We found that RalA activity increased significantly in PI3K? knockout mice. Furthermore, NMDAR-LTD-inducing stimuli did not increase RalA activity in PI3K? knockout mice. These results suggest that constitutively increased RalA activity occludes further increases in RalA activity during induction of LTD, causing impaired NMDAR-LTD. We propose that PI3K? regulates the activity of RalA, which is one of the molecular mechanisms inducing NMDAR dependent LTD. PMID:23433113

Sim, Su-Eon; Lee, Hye-Ryeon; Kim, Jae-Ick; Choi, Sun-Lim; Bakes, Joseph; Jang, Deok-Jin; Lee, Kyungmin; Han, Kihoon; Kim, Eunjoon; Kaang, Bong-Kiun

2013-02-01

300

Long-Term Observations of Active Hydrothermal Processes on the Gorda Ridge: The Sea Cliff Hydrothermal Field and Escanaba Trough  

NASA Astrophysics Data System (ADS)

The two known sites of high temperature hydrothermal venting on the Gorda Ridge are the northerly Sea Cliff hydrothermal field and the southerly Escanaba Trough. Indications that the Sea Cliff field (GR-14) existed were first obtained from hydrographic work in 1985, and confirmed by the discovery of the site in 1988. Our cruise at the site in 2000 was the first time fluids were sampled, and we subsequently also collected fluids in 2002. One reason the Sea Cliff field is of interest is its location ˜3km east of the axis of spreading. It was suggested that the site might therefore be relatively 'old,' or at least located on 'older crust' at the 5.5cm/yr spreading rate. All of the hydrothermal fluids from Sea Cliff are low chlorinity, or vapor phase, contrary to its previous interpretation as an older hydrothermal system which are generally interpreted to vent fluids with chloride contents greater than seawater. Our other chemical data also support our interpretation that this system is not tapping highly altered crust. In spite of the >300° C measured temperatures of the vent fluids, they are strikingly clear, and have Fe contents ˜30 umoles/kg, about 2 orders of magnitude less than typical. The low Fe, and other transition metals, are likely a result of the slightly elevated pH (4.5 at 25° C) of these fluids. Possible causes of the elevated pH include: incorporation of buried organic matter, dissolution of fracture-filling calcite, supercritical phase separation phenomena, and other reactions that may impact the proton balance in the fluids, as there is no sediment cover at this site, and no (chemical) evidence for buried sediments. The very low metal contents are in agreement with the water column signals observed in 1985, suggesting the fluids have not changed in ˜20 years, and that the site was not impacted by the seismic activity on the Gorda Ridge in 1996 and 2001. Hydrothermal fluids were first collected from Escanaba Trough (NESCA) in 1988, and this site was subsequently drilled by ODP in 1996. Our fluid samples collected in 2000 and 2002 have the same compositions as those collected in 1988. All of the fluids we collected venting from this site are high chlorinity (brines), while ODP also encountered low chlorinity vapors subsurface. We propose a model to explain why the brines are venting preferentially to the vapor phase at this site. Chemical stability in hydrothermal systems, as in these two cases from the Gorda Ridge, are in stark contrast to observations of variability elsewhere on the global mid-ocean ridge system. The time scales and explanations for the fundamental causes of these differences remain poorly understood.

von Damm, K. L.; Parker, C. M.; Lilley, M. D.; Olson, E. J.; Zierenberg, R. A.; McClain, J. S.; Clague, D. A.

2004-12-01

301

Long-Term Effects of Highly Active Antiretroviral Therapy on CD4+ Cell Evolution among Children and Adolescents Infected with HIV: 5 Years and Counting  

PubMed Central

Background Lower percentages of CD4+ T lymphocytes are associated with adverse clinical outcomes among children and adolescents infected with human immunodeficiency virus (HIV). CD4+ lymphocyte percentage generally increases with receipt of highly active antiretroviral therapy (HAART), but long-term follow-up is required to assess whether these increases in CD4+ cell percentage are maintained and whether they lead to normal CD4+ cell percentages in children with severe immunosuppression. Methods The study population included 1236 children and adolescents perinatally infected with HIV who were enrolled in a US-based multicenter prospective cohort study (Pediatric AIDS Clinical Trials Group 219/219C) and who were not receiving HAART at study initiation. We estimated the effects of HAART, HAART with protease inhibitors, and HAART with nonnucleoside reverse-transcriptase inhibitors on CD4+ cell percentage, using marginal structural models to account for confounding by severity. Results Initiation of any type of HAART increased CD4+ cell percentage by 2.34% (95% confidence interval, 1.35%–3.33%) in the first year, relative to noninitiation of HAART. The substantial increases in CD4+ cell percentage observed after the first year of experience with these combination therapies were followed by relatively smaller increases that continued for 5 years after initiation. Although larger increases in CD4+ cell percentage were observed among children with a greater degree of immunosuppression at baseline, the mean CD4+ cell percentage after 5 years of HAART did not reach normal levels. Conclusions Our study supports the initiation of HAART in children before severe immunosuppression occurs for long-term maintenance of normal CD4+ cell percentages. This beneficial result must be weighed against the evidence of potential adverse events associated with the prolonged use of such therapy. PMID:18426371

Patel, Kunjal; Hernán, Miguel A.; Williams, Paige L.; Seeger, John D.; McIntosh, Kenneth; Van Dyke, Russell B.; Seage, George R.

2011-01-01

302

Functional electrical stimulation of long-term denervated, degenerated human skeletal muscle: estimating activation using T2-parameter magnetic resonance imaging methods.  

PubMed

Functional electrical stimulation (FES) of long-term denervated, degenerated human skeletal muscle has proven to be a suitable method for improving a number of physiological parameters. The underlying mechanisms of activation of a denervated muscle fiber can be described with suitably modified and extended Hodgin-Huxley type models, coupled with three-dimensional (3D) finite element models of the surrounding electrical field. Regions of activation within a muscle can be determined using a 3D computer model. However, simulation results have not yet been validated experimentally. During and immediately after exercise, muscle shows increased T2-relaxation times. It is thus possible to estimate muscle activation noninvasively and spatially resolved with the magnetic resonance imaging (MRI) method of T2 mapping, which was, therefore, chosen as a suitable validation approach. Six patients were scanned prior to FES training with a multislice multiecho MSME-sequence at 3 Tesla and then asked to perform one of their regular daily training-sessions (leg extensions). Subjects were then repositioned in the MR-scanner and two to five postexercise scans were recorded. Pre- and postexercise scans were coregistered and T2-parameter maps were calculated. Regions of interest (ROIs) were drawn manually around quadriceps femoris and its antagonists. Activation was detected in all patients. In well-trained patients, activation in the quadriceps was found to be considerably higher than in its antagonists. These experimental results will help further improve existing models of FES of denervated degenerated human skeletal muscle. PMID:18782129

Mandl, Thomas; Meyerspeer, Martin; Reichel, Martin; Kern, Helmut; Hofer, Christian; Mayr, Winfried; Moser, Ewald

2008-08-01

303

Influences of a DRD2 polymorphism on updating of long-term memory representations and caudate BOLD activity: Magnification in aging.  

PubMed

A number of genetic polymorphisms are related to individual differences in cognitive performance. Striatal dopamine (DA) functions, associated with cognitive performance, are linked to the TaqIA polymorphism of the DRD2/ANKK1 gene. In humans, presence of an A1 allele of the DRD2/ANKK1-TaqIA polymorphism is related to reduced density of striatal DA D2 receptors. The resource-modulation hypothesis assumes that aging-related losses of neurochemical and structural brain resources modulate the extent to which genetic variations affect cognitive functioning. Here, we tested this hypothesis using functional MRI during long-term memory (LTM) updating in younger and older carriers and noncarriers of the A1-allele of the TaqIa polymorphism. We demonstrate that older A1-carriers have worse memory performance, specifically during LTM updating, compared to noncarriers. Moreover, A1-carriers exhibited less blood oxygen level-dependent (BOLD) activation in left caudate nucleus, a region critical to updating. This effect was only seen in older adults, suggesting magnification of genetic effects on functional brain activity in aging. Further, a positive relationship between caudate BOLD activation and updating performance among non-A1 carriers indicated that caudate activation was behaviorally relevant. These results demonstrate a link between the DRD2/ANKK1-TaqIA polymorphism and neurocognitive deficits related to LTM updating, and provide novel evidence that this effect is magnified in aging. Hum Brain Mapp, 2014. © 2014 Wiley Periodicals, Inc. PMID:25486867

Persson, Jonas; Rieckmann, Anna; Kalpouzos, Grégoria; Fischer, Håkan; Bäckman, Lars

2014-12-01

304

Microcalorimetric study of the effects of long-term fertilization on soil microbial activity in a wheat field on the Loess Plateau.  

PubMed

The effects of the long-term inorganic (nitrogen, N; phosphate, P) and organic (manure, M; straw, S) fertilizers/managemenet individually and in combinations (N, NP, SNP, M, and MNP) on soil microbial activity were investigated in a wheat field on the Loess Plateau, China. Microcalorimetry was used to determine microbial activity under different treatments. Nearly 30 years of consecutive fertilization has altered the culturable population of soil bacteria and fungi, the highest ones were detected in the treatments of manure and MNP, followed by the NP and SNP treatments. The microbial growth rate constant (?/h(-1)) was significantly greater in the MNP treatment than all the other treatments. The total heat exchange values (Q/J) were the highest in the MNP and NP treatments, which were significantly different from the N and M treatments. The peak height (P(t)/?W) were significantly higher in MNP and NP treatments than in the remaining treatments. The peak time values (t(p)/h) among the MNP, NP, SNP and M, N and CK treatments were significantly different. In general, comparing with control, soil microbial activity was much higher in MNP, NP and SNP treatments, all including the phosphate fertilizer. Our results showed that the application of inorganic fertilizer and organic manure have positive effects on multiple soil chemical parameters, soil microorganism abundance and activity, and hence crop yield. PMID:25134677

Zhang, Qi; Liu, Xiaomei; Ma, Xiaojun; Fang, Jian; Fan, Tinglu; Wu, Fasi; An, Lizhe; Feng, Huyuan

2014-12-01

305

Soil microbiological properties and enzymatic activities of long-term post-fire recovery in dry and semiarid Aleppo pine (Pinus halepensis M.) forest stands  

NASA Astrophysics Data System (ADS)

Wildfires affecting forest ecosystems and post-fire silvicultural treatments may cause considerable changes in soil properties. The capacity of different microbial groups to recolonize soil after disturbances is crucial for proper soil functioning. The aim of this work was to investigate some microbial soil properties and enzyme activities in semiarid and dry Aleppo pine (Pinus halepensis M.) forest stands. Different plots affected by a wildfire event 17 years ago without or with post-fire silvicultural treatments five years after the fire event were selected. A mature Aleppo pine stand unaffected by wildfire and not thinned was used as a control. Physicochemical soil properties (soil texture, pH, carbonates, organic matter, electrical conductivity, total N and P), soil enzymes (urease, phosphatase, ?-glucosidase and dehydrogenase activities), soil respiration and soil microbial biomass carbon were analysed in the selected forests areas and plots. The main finding was that long time after this fire event produces no differences in the microbiological soil properties and enzyme activities of soil after comparing burned and thinned, burned and not thinned, and mature plots. Thus, the long-term consequences and post-fire silvicultural management in the form of thinning have a significant effect on the site recovery after fire. Moreover, significant site variation was generally seen in soil enzyme activities and microbiological parameters. We conclude that total vegetation restoration normalises microbial parameters, and that wildfire and post-fire silvicultural treatments are not significant factors of soil properties after 17 years.

Hedo, J.; Lucas-Borja, M. E.; Wic, C.; Andrés Abellán, M.; de Las Heras, J.

2014-10-01

306

Myosin II ATPase Activity Mediates the Long-Term Potentiation-Induced Exodus of Stable F-Actin Bound by Drebrin A from Dendritic Spines  

PubMed Central

The neuronal actin-binding protein drebrin A forms a stable structure with F-actin in dendritic spines. NMDA receptor activation causes an exodus of F-actin bound by drebrin A (DA-actin) from dendritic spines, suggesting a pivotal role for DA-actin exodus in synaptic plasticity. We quantitatively assessed the extent of DA-actin localization to spines using the spine-dendrite ratio of drebrin A in cultured hippocampal neurons, and found that (1) chemical long-term potentiation (LTP) stimulation induces rapid DA-actin exodus and subsequent DA-actin re-entry in dendritic spines, (2) Ca2+ influx through NMDA receptors regulates the exodus and the basal accumulation of DA-actin, and (3) the DA-actin exodus is blocked by myosin II ATPase inhibitor, but is not blocked by myosin light chain kinase (MLCK) or Rho-associated kinase (ROCK) inhibitors. These results indicate that myosin II mediates the interaction between NMDA receptor activation and DA-actin exodus in LTP induction. Furthermore, myosin II seems to be activated by a rapid actin-linked mechanism rather than slow MLC phosphorylation. Thus the myosin-II mediated DA-actin exodus might be an initial event in LTP induction, triggering actin polymerization and spine enlargement. PMID:24465547

Mizui, Toshiyuki; Sekino, Yuko; Yamazaki, Hiroyuki; Ishizuka, Yuta; Takahashi, Hideto; Kojima, Nobuhiko; Kojima, Masami; Shirao, Tomoaki

2014-01-01

307

Interacting memory systems-does EEG alpha activity respond to semantic long-term memory access in a working memory task?  

PubMed

Memory consists of various individual processes which form a dynamic system co-ordinated by central (executive) functions. The episodic buffer as direct interface between episodic long-term memory (LTM) and working memory (WM) is fairly well studied but such direct interaction is less clear in semantic LTM. Here, we designed a verbal delayed-match-to-sample task specifically to differentiate between pure information maintenance and mental manipulation of memory traces with and without involvement of access to semantic LTM. Task-related amplitude differences of electroencephalographic (EEG) oscillatory brain activity showed a linear increase in frontal-midline theta and linear suppression of parietal beta amplitudes relative to memory operation complexity. Amplitude suppression at upper alpha frequency, which was previously found to indicate access to semantic LTM, was only sensitive to mental manipulation in general, irrespective of LTM involvement. This suggests that suppression of upper EEG alpha activity might rather reflect unspecific distributed cortical activation during complex mental processes than accessing semantic LTM. PMID:25545793

Berger, Barbara; Omer, Serif; Minarik, Tamas; Sterr, Annette; Sauseng, Paul

2014-01-01

308

Myosin II ATPase activity mediates the long-term potentiation-induced exodus of stable F-actin bound by drebrin A from dendritic spines.  

PubMed

The neuronal actin-binding protein drebrin A forms a stable structure with F-actin in dendritic spines. NMDA receptor activation causes an exodus of F-actin bound by drebrin A (DA-actin) from dendritic spines, suggesting a pivotal role for DA-actin exodus in synaptic plasticity. We quantitatively assessed the extent of DA-actin localization to spines using the spine-dendrite ratio of drebrin A in cultured hippocampal neurons, and found that (1) chemical long-term potentiation (LTP) stimulation induces rapid DA-actin exodus and subsequent DA-actin re-entry in dendritic spines, (2) Ca(2+) influx through NMDA receptors regulates the exodus and the basal accumulation of DA-actin, and (3) the DA-actin exodus is blocked by myosin II ATPase inhibitor, but is not blocked by myosin light chain kinase (MLCK) or Rho-associated kinase (ROCK) inhibitors. These results indicate that myosin II mediates the interaction between NMDA receptor activation and DA-actin exodus in LTP induction. Furthermore, myosin II seems to be activated by a rapid actin-linked mechanism rather than slow MLC phosphorylation. Thus the myosin-II mediated DA-actin exodus might be an initial event in LTP induction, triggering actin polymerization and spine enlargement. PMID:24465547

Mizui, Toshiyuki; Sekino, Yuko; Yamazaki, Hiroyuki; Ishizuka, Yuta; Takahashi, Hideto; Kojima, Nobuhiko; Kojima, Masami; Shirao, Tomoaki

2014-01-01

309

Brain-derived neurotrophic factor contributes to spinal long-term potentiation and mechanical hypersensitivity by activation of spinal microglia in rat.  

PubMed

It has been shown that following peripheral nerve injury brain-derived neurotrophic factor (BDNF) released by activated microglia contributes to neuropathic pain, but whether BDNF affects the function of microglia is still unknown. In the present work we found that spinal application of BDNF, which induced long-term potentiation (LTP) of C-fiber evoked field potentials, activated spinal microglia in naïve animals, while pretreatment with microglia inhibitor minocycline blocked BDNF-induced LTP. In addition, following LTP induction by BDNF, both phosphorylated Src-family kinases (p-SFKs) and phosphorylated p38 mitogen-activated protein kinase (p-p38 MAPK) were up-regulated only in spinal microglia but not in neurons and astrocytes, whilst spinal application of SFKs inhibitor (PP2 or SU6656) or p38 MAPK inhibitor (SB203580) blocked BDNF-induced LTP and suppressed microglial activation. As spinal LTP at C-fiber synapses is considered to underlie neuropathic pain, we subsequently examined whether BDNF may contribute to mechanical hypersensitivity by activation of spinal microglia using spared nerve injury (SNI) model. Following SNI BDNF and TrkB receptor were up-regulated mainly in dorsal horn neurons and in activated microglia, and p-SFKs and p-p38 MAPK were increased exclusively in microglia. Intrathecal injection of BDNF scavenger TrkB-Fc starting before SNI, which prevented the behavioral sign of neuropathic pain, suppressed both microglial activation and the up-regulation of p-SFKs and p-p38 MAPK produced by SNI. Thus, the increased BDNF/TrkB signaling in spinal dorsal horn may contribute to neuropathic pain by activation of microglia following peripheral nerve injury and inhibition of SFKs or p38 MAPK may selectively inhibit microglia in spinal dorsal horn. PMID:20933591

Zhou, Li-Jun; Yang, Tao; Wei, Xiao; Liu, Yong; Xin, Wen-Jun; Chen, Yuan; Pang, Rui-Ping; Zang, Ying; Li, Yong-Yong; Liu, Xian-Guo

2011-02-01

310

Long-term interleukin 2-dependent growth and cytotoxic activity of tumor-infiltrating lymphocytes from human squamous cell carcinomas of the head and neck.  

PubMed

Tumor-infiltrating lymphocytes (TIL) from 16 squamous cell carcinomas of head and neck (SCCH&N) and four nonsquamous cell carcinomas were studied. By immunoperoxidase staining in situ, the tumors studied were found to be infiltrated mainly by CD2+CD3+ cells, and 30-50% of the T-lymphocytes were HLA-DR positive and transferrin-receptor positive. They also contained scarce NKH1+ cells. When TIL as well as autologous peripheral blood lymphocytes (A-PBL) were cultured in 1,000 U/ml of recombinant interleukin 2 (rIL2), TIL proliferated in all but three cases, and A-PBL proliferated in all but two cases. Frequently, but not always, TIL expanded better than A-PBL. The median expansion for TIL was 100-fold and that for A-PBL was 31-fold in long-term cultures maintained for up to 88 days. TIL obtained from untreated primary SCCH&N were initially delayed for up to 20 days in their proliferative response to rIL2, but then grew well. In contrast, TIL and A-PBL from metastatic SCCH&N either did not proliferate or were delayed in their proliferative response for up to 40 or 50 days. A-PBL, when tested early (days 10-20 in culture), showed the highest cytotoxic activity against cultured and fresh tumor-cell targets, whereas TIL were most active later in culture (days 20-30). On a per culture basis, TIL achieved higher antitumor cytotoxicity than A-PBL. By day 80, lytic activities of most TIL cultures declined to undetectable levels. CD3+Leu19- T-lymphocytes were the major expanding cell population in most TIL cultures. However, these cells were poor mediators of antitumor cytotoxicity in TIL or A-PBL cultures as shown in cell sorting experiments. The antitumor effector cells expressed CD3-Leu19+ and/or CD3+Leu19+ phenotypes. On Giemsa-stained smears, these two types of IL2-expanded effector cells had the morphology of large granular lymphocytes. Our results indicate that TIL from human SCCH&N could be expanded and reach high levels of antitumor effector function in long-term cultures with rIL2. PMID:3315186

Heo, D S; Whiteside, T L; Johnson, J T; Chen, K N; Barnes, E L; Herberman, R B

1987-12-01

311

The Long Term Impact of Cataract Surgery on Quality of Life, Activities and Poverty: Results from a Six Year Longitudinal Study in Bangladesh and the Philippines  

PubMed Central

Background Cataract surgery has been shown to improve quality of life and household economy in the short term. However, it is unclear whether these benefits are sustained over time. This study aims to assess the six year impact of cataract surgery on health related quality of life (HRQoL), daily activities and economic poverty in Bangladesh and The Philippines. Methods and Findings This was a longitudinal study. At baseline people aged ?50 years with visual impairment due to cataract (‘cases’) and age-, sex-matched controls without visual impairment were interviewed about vision specific and generic HRQoL, daily activities and economic indicators (household per capita expenditure, assets and self-rated wealth). Cases were offered free or subsidised cataract surgery. Cases and controls were re-interviewed approximately one and six years later. At baseline across the two countries there were 455 cases and 443 controls. Fifty percent of cases attended for surgery. Response rates at six years were 47% for operated cases and 53% for controls. At baseline cases had poorer health and vision related QoL, were less likely to undertake productive activities, more likely to receive assistance with activities and were poorer compared to controls (p<0.05). One year after surgery there were significant increases in HRQoL, participation and time spent in productive activities and per capita expenditure and reduction in assistance with activities so that the operated cases were similar to controls. These increases were still evident after six years with the exception that time spent on productive activities decreased among both cases and controls. Conclusion Cataract causing visual loss is associated with reduced HRQoL and economic poverty among older adults in low-income countries. Cataract surgery improves the HRQoL of the individual and economy of the household. The findings of this study suggest these benefits are sustained in the long term. PMID:24747192

Danquah, Lisa; Kuper, Hannah; Eusebio, Cristina; Rashid, Mamunur Akm; Bowen, Liza; Foster, Allen; Polack, Sarah

2014-01-01

312

Long-Term Forecast of Space Weather in Real-Time.  

NASA Astrophysics Data System (ADS)

The scaling character of the cosmic ray fluctuation dynamics detected in a wide interval of the scales of intensity decreases assumes the long-term (2-3 Bartel`s rotations) forecast of the solar sporadic activity. It is achieved by using the cosmic ray scintillation index 5-min values averaged by Bartels rotations.

Kozlov, V. I.; Starodubtsev, S. A.; Turpanov, A. A.; Grigoryev, V. G.; Nikolaev, V. S.; Prikhodko, A. N.

2001-08-01

313

Long term virological, immunological and mortality outcomes in a cohort of HIV-infected female sex workers treated with highly active antiretroviral therapy in Africa  

PubMed Central

Background Concerns have been raised that marginalised populations may not achieve adequate compliance to antiretroviral therapy. Our objective was to describe the long-term virological, immunological and mortality outcomes of providing highly active antiretroviral therapy (HAART) with strong adherence support to HIV-infected female sex workers (FSWs) in Burkina Faso and contrast outcomes with those obtained in a cohort of regular HIV-infected women. Methods Prospective study of FSWs and non-FSWs initiated on HAART between August 2004 and October 2007. Patients were followed monthly for drug adherence (interview and pill count), and at 6-monthly intervals for monitoring CD4 counts and HIV-1 plasma viral loads (PVLs) and clinical events. Results 95 women, including 47 FSWs, were followed for a median of 32 months (interquartile range [IQR], 20-41). At HAART initiation, the median CD4 count was 147 cells/?l (IQR, 79-183) and 144 cells/?l (100-197), and the mean PVLs were 4.94 log10copies/ml (95% confidence interval [CI], 4.70-5.18) and 5.15 log10 copies/ml (4.97-5.33), in FSWs and non-FSWs, respectively. Four FSWs died during follow-up (mortality rate: 1.7 per 100 person-years) and none among other women. At 36 months, the median CD4 count increase was 230 cells/?l (IQR, 90-400) in FSWs vs. 284 cells/?l (193-420) in non-FSWs; PVL was undetectable in 81.8% (95% CI, 59.7-94.8) of FSWs vs. 100% (83.9-100) of non-FSWs; and high adherence to HAART (> 95% pills taken) was reported by 83.3% (95% CI, 67.2-93.6), 92.1% (95% CI, 78.6-98.3), and 100% (95% CI, 54.1-100) of FSWs at 6, 12, and 36 months after HAART initiation, respectively, with no statistical difference compared to the pattern observed among non-FSWs. Conclusions Clinical and biological benefits of HAART can be maintained over the long term among FSWs in Africa and could also lead to important public health benefits. PMID:21917177

2011-01-01

314

Forecasting the solar activity cycle: new insights  

NASA Astrophysics Data System (ADS)

Having advance knowledge of solar activity is important because the Sun's magnetic output governs space weather and impacts technologies reliant on space. However, the irregular nature of the solar cycle makes solar activity predictions a challenging task. This is best achieved through appropriately constrained solar dynamo simulations and as such the first step towards predictions is to understand the underlying physics of the solar dynamo mechanism. In Babcock-Leighton type dynamo models, the poloidal field is generated near the solar surface whereas the toroidal field is generated in the solar interior. Therefore a finite time is necessary for the coupling of the spatially segregated source layers of the dynamo. This time delay introduces a memory in the dynamo mechanism which allows forecasting of future solar activity. Here we discuss how this forecasting ability of the solar cycle is affected by downward turbulent pumping of magnetic flux. With significant turbulent pumping the memory of the dynamo is severely degraded and thus long term prediction of the solar cycle is not possible; only a short term prediction of the next cycle peak may be possible based on observational data assimilation at the previous cycle minimum.

Nandy, Dibyendu; Karak, Bidya Binay

2013-07-01

315

Bidirectional and Multi-User Telerehabilitation System: Clinical Effect on Balance, Functional Activity, and Satisfaction in Patients with Chronic Stroke Living in Long-Term Care Facilities  

PubMed Central

Background The application of internet technology for telerehabilitation in patients with stroke has developed rapidly. Objective The current study aimed to evaluate the effect of a bidirectional and multi-user telerehabilitation system on balance and satisfaction in patients with chronic stroke living in long-term care facilities (LTCFs). Method This pilot study used a multi-site, blocked randomization design. Twenty-four participants from three LTCFs were recruited, and the participants were randomly assigned into the telerehabilitation (Tele) and conventional therapy (Conv) groups within each LTCF. Tele group received telerehabilitation but the Conv group received conventional therapy with two persons in each group for three sessions per week and for four weeks. The outcome measures included Berg Balance Scale (BBS), Barthel Index (BI), and the telerehabilitation satisfaction of the participants. Setting A telerehabilitation system included “therapist end” in a laboratory, and the “client end” in LTCFs. The conventional therapy was conducted in LTCFs. Results Training programs conducted for both the Tele and Conv groups showed significant effects within groups on the participant BBS as well as the total and self-care scores of BI. No significant difference between groups could be demonstrated. The satisfaction of participants between the Tele and the Conv groups also did not show significant difference. Conclusions This pilot study indicated that the multi-user telerehabilitation program is feasible for improving the balance and functional activity similar to conventional therapy in patients with chronic stroke living in LTCFs. PMID:25019632

Lin, Kwan-Hwa; Chen, Chin-Hsing; Chen, You-Yin; Huang, Wen-Tzeng; Lai, Jin-Shin; Yu, Shang-Ming; Chang, Yuan-Jen

2014-01-01

316

Geochemical changes and microbial activities during CO2 storage - Long-term experiments under in situ conditions within the frame of CO2SINK  

NASA Astrophysics Data System (ADS)

Within the frame of the CO2SINK project, CO2 is injected into a saline aquifer of the Stuttgart formation (Triassic, Middle Keuper) at a depth of about 640 m below surface near Ketzin (Northeast German Basin, about 40 km west of Berlin) (Schilling et al., 2009). The injection of CO2 may induce a variety of geochemical changes in the reservoir system. Inorganic components may be dissolved from mineral phases (Wigand et al., 2008) and mineral precipitation from fluid components (Ketzer et al., 2009) may occur. In addition, organic molecules may be relocated, since supercritical CO2 is an excellent solvent for organic components. These geochemical shifts probably affect the microbial community composition and activity. The dissolution and precipitation of minerals, as well as corresponding microbial processes (Bennet et al., 2001) can affect reservoir permeability. In order to detect and quantify changes in geochemical characteristics and microbial processes during CO2storage and to estimate their impact on storage efficiency long-term experiments under in situ P-T conditions are performed. Freshly drilled sandstone sections from the target reservoir at Ketzin from a depth of about 630 m were incubated together with synthetic brine (20 % lower total dissolved solids than the Ketzin reservoir fluid) in high pressure vessels at 5.5 MPa and 40 ° C since September 2007. Since outer core sections were contaminated with drilling mud, as shown with fluorescein tracer detection (Wandrey et al., 2010), only clean inner core sections were used for long-term experiments to avoid contamination with microorganisms, as well as organic and inorganic mud components. After 15, 21 and 24 month fluid and rock samples were taken for chemical, microbial, mineralogical and petrophysical analyses. In fluid samples the concentrations of Ca2+, Mg2+, and K+ were found to exceed those of the Ketzin reservoir fluid. Assuming chemical equilibrium between mineral and formation brine, observed effects are probably caused by mineral dissolution in response to CO2 exposure. In consistence with inorganic concentration declines, XRD, SEM and EMP analyses suggest feldspar dissolution (Fischer et al., EGU GA 2010). A shift to larger pore radii was observed as well (Zemke et al., 2010). Organic acids are a marker for the presence of active microorganisms. They are intermediate products of the bacterial metabolism. Furthermore, if excreted, organic acids can locally decrease the pH at the bacterial attachment site and may support mineral dissolution (Welch and McPhail et al., 2003). After 15 month organic acid concentrations in vessel fluids were 2 to 7 times lower than the expected concentration (based on pore water analysis). To investigate the concentration trend during CO2 exposure, the analysis of further samples is in progress. In order to characterise the microbial community of the reservoir sandstone, initial 16S taxonomic studies were performed. So fare 16S rRNA gene sequences of chemoheterotrophic bacteria (Methylophilales bacterium, Rhizobium radiobacter, Arthrobacter, Sphingomonas), and hydrogen oxidizing bacteria (Ralstonia, Hydrogenophaga) were obtained. During the long-term exposure experiment only minor changes of the microbial community composition were observed, reflecting the adaptation of the microorganisms to the modified conditions. The quantification of metabolic groups and relevant microbial activities, e.g. metal and sulfate reduction, using Real-Time PCR and FISH in untreated and CO2 exposed samples will help to quantify bacterial processes and to assess their long-term influence on storage efficiency. Bennet P.C., Rogers J.R., Choi W.J. (2001) Geomicrobiol J 18, pp. 3 Fischer S., Zemke K., Liebscher A., Wandrey M., CO2SINK Group, EGU General Assembly 2010, Vienna Ketzer J.M., Iglesias R., Einloft S., Dullius J., Ligabue R., de Lima V. (2009) Appl Geochem 24(5), pp. 760 Schilling F., Borm G., Würdemann H., Möller F., Kühn M., CO2SINK Group (2009) Energy Procedia 1, 2029-2035 Wandrey M., Morozova D., Zettlitzer M., Würdemann H., CO2

Wandrey, Maren; Scherf, Ann-Kathrin; Vieth, Andrea; Zettlitzer, Michael; Würdemann, Hilke

2010-05-01

317

Long-Term Vision and Non-Vision Dominant Behavioral Deficits in the 2-VO Rats Are Accompanied by Time and Regional Glial Activation in the White Matter  

PubMed Central

The permanent occlusion of common carotid arteries (2-VO) in rats has been shown to induce progressive and long-lasting deficits in cognitive performance, however, whether these aberrant behaviors are attributed to visual dysfunction or cognitive impairment and what are the underlying mechanisms, remain controversial. In the present study, vision dominant (Morris water maze) and non-vision dominant (voice-cued fear conditioning) behavioral tests were assigned to comprehensively evaluate the influence of 2-VO lesion on cognitive behaviors. In the Morris water maze test, escape latencies of 2-VO rats were markedly increased in both hidden and unfixed visible platform tasks, which were accompanied by severe retinal damage. In the voice-cued fear conditioning test, significant reduction in the percentage of freezing behavior was observed at 60 days after 2-VO lesion. Chronic lesion by 2-VO failed to cause noticeable changes in the grey matter, as indicated by intact hippocampal and prefrontal cortical structures, sustained synaptic protein levels and glial cell numbers. In contrast, aberrant arrangement of myelinated axons was observed in the optic tract, but not in the corpus callosum and inner capsule of 2-VO rats. Concurrently, marked astrocyte proliferation and microglia activation in the optic tract occurred at 3 days after 2-VO lesion, and continued for up to 60 days. Differently, robust glial activation was observed in the corpus callosum at 3 days after 2-VO surgery, and then gradually returned to the baseline level at 14 and 60 days. Our study reported for the first time about the effect of 2-VO on the long-term cognitive impairment in the non-vision dominant fear conditioning test, which may be more applicable than the Morris water maze test for assessing 2-VO associated cognitive function. The time and region specific glial activation in the white matter may relate to retinal impairment, even behavioral deficits, in the setting of chronic cerebral hypoperfusion. PMID:24968196

Ruan, Zhi; Lei, Yun; Chen, Yu Ting; Zhang, Hai Yan

2014-01-01

318

Circadian activity rhythms and voluntary ethanol intake in male and female ethanol-preferring rats: Effects of long-term ethanol access.  

PubMed

Chronic alcohol (ethanol) intake alters fundamental properties of the circadian clock. While previous studies have reported significant alterations in free-running circadian period during chronic ethanol access, these effects are typically subtle and appear to require high levels of intake. In the present study we examined the effects of long-term voluntary ethanol intake on ethanol consumption and free-running circadian period in male and female, selectively bred ethanol-preferring P and HAD2 rats. In light of previous reports that intermittent access can result in escalated ethanol intake, an initial 2-week water-only baseline was followed by either continuous or intermittent ethanol access (i.e., alternating 15-day epochs of ethanol access and ethanol deprivation) in separate groups of rats. Thus, animals were exposed to either 135 days of continuous ethanol access or to five 15-day access periods alternating with four 15-day periods of ethanol deprivation. Animals were maintained individually in running-wheel cages under continuous darkness throughout the experiment to allow monitoring of free-running activity and drinking rhythms, and 10% (v/v) ethanol and plain water were available continuously via separate drinking tubes during ethanol access. While there were no initial sex differences in ethanol drinking, ethanol preference increased progressively in male P and HAD2 rats under both continuous and intermittent-access conditions, and eventually exceeded that seen in females. Free-running period shortened during the initial ethanol-access epoch in all groups, but the persistence of this effect showed complex dependence on sex, breeding line, and ethanol-access schedule. Finally, while females of both breeding lines displayed higher levels of locomotor activity than males, there was little evidence for modulation of activity level by ethanol access. These results are consistent with previous findings that chronic ethanol intake alters free-running circadian period, and show further that the development of chronobiological tolerance to ethanol may vary by sex and genotype. PMID:25281289

Rosenwasser, Alan M; McCulley, Walter D; Fecteau, Matthew

2014-11-01

319

N-cadherin{sup +} HSCs in fetal liver exhibit higher long-term bone marrow reconstitution activity than N-cadherin{sup -} HSCs  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer High N-cad expression was detected in E12.5 mouse FL LT-HSCs (EPCR{sup +} LSK cells). Black-Right-Pointing-Pointer Immunohistochemically, N-cad{sup +} HSCs co-localized with sinusoidal ECs (Lyve-1{sup +} cells) in E12.5 FL, but these gradually detached in E15.5 and E18.5 FL. Black-Right-Pointing-Pointer N-cad{sup +} LSK cells in E12.5 FL exhibited higher LTR activity versus N-cad{sup -} LSK cells, which decreased in E15.5 and E18.5. Black-Right-Pointing-Pointer N-cad expression may confer high LTR activity to HSCs by facilitating interactions with the perisinusoidal niche in FL. -- Abstract: Adult hematopoietic stem cells (HSCs) are maintained in a microenvironment known as the stem cell niche. The regulation of HSCs in fetal liver (FL) and their niche, however, remains to be elucidated. In this study, we investigated the role of N-cadherin (N-cad) in the maintenance of HSCs during FL hematopoiesis. By using anti-N-cad antibodies (Abs) produced by our laboratory, we detected high N-cad expression in embryonic day 12.5 (E12.5) mouse FL HSCs, but not in E15.5 and E18.5 FL. Immunofluorescence staining revealed that N-cad{sup +}c-Kit{sup +} and N-cad{sup +} endothelial protein C receptor (EPCR){sup +} HSCs co-localized with Lyve-1{sup +} sinusoidal endothelial cells (ECs) in E12.5 FL and that some of these cells also expressed N-cad. However, N-cad{sup +} HSCs were also observed to detach from the perisinusoidal niche at E15.5 and E18.5, concomitant with a down-regulation of N-cad and an up-regulation of E-cadherin (E-cad) in hepatic cells. Moreover, EPCR{sup +} long-term (LT)-HSCs were enriched in the N-cad{sup +}Lin{sup -}Sca-1{sup +}c-Kit{sup +} (LSK) fraction in E12.5 FL, but not in E15.5 or E18.5 FL. In a long-term reconstitution (LTR) activity assay, higher engraftment associated with N-cad{sup +} LSK cells versus N-cad{sup -} LSK cells in E12.5 FL when transplanted into lethally irradiated recipient mice. However, the higher engraftment of N-cad{sup +} LSK cells decreased subsequently in E15.5 and E18.5 FL. It is possible that N-cad expression conferred higher LTR activity to HSCs by facilitating interactions with the perisinusoidal niche, especially at E12.5. The down-regulation of N-cad during FL hematopoiesis may help us better understand the regulation and mobility of HSCs before migration into BM.

Toyama, Hirofumi; Arai, Fumio; Hosokawa, Kentaro; Ikushima, Yoshiko Matsumoto [Department of Cell Differentiation, The Sakaguchi Laboratory of Developmental Biology, School of Medicine, Keio University, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan)] [Department of Cell Differentiation, The Sakaguchi Laboratory of Developmental Biology, School of Medicine, Keio University, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan); Suda, Toshio, E-mail: sudato@z3.keio.jp [Department of Cell Differentiation, The Sakaguchi Laboratory of Developmental Biology, School of Medicine, Keio University, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan)] [Department of Cell Differentiation, The Sakaguchi Laboratory of Developmental Biology, School of Medicine, Keio University, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan)

2012-11-23

320

Activation instead of blocking mesolimbic dopaminergic reward circuitry is a preferred modality in the long term treatment of reward deficiency syndrome (RDS): a commentary  

PubMed Central

Background and hypothesis Based on neurochemical and genetic evidence, we suggest that both prevention and treatment of multiple addictions, such as dependence to alcohol, nicotine and glucose, should involve a biphasic approach. Thus, acute treatment should consist of preferential blocking of postsynaptic Nucleus Accumbens (NAc) dopamine receptors (D1-D5), whereas long term activation of the mesolimbic dopaminergic system should involve activation and/or release of Dopamine (DA) at the NAc site. Failure to do so will result in abnormal mood, behavior and potential suicide ideation. Individuals possessing a paucity of serotonergic and/or dopaminergic receptors, and an increased rate of synaptic DA catabolism due to high catabolic genotype of the COMT gene, are predisposed to self-medicating any substance or behavior that will activate DA release, including alcohol, opiates, psychostimulants, nicotine, gambling, sex, and even excessive internet gaming. Acute utilization of these substances and/or stimulatory behaviors induces a feeling of well being. Unfortunately, sustained and prolonged abuse leads to a toxic" pseudo feeling" of well being resulting in tolerance and disease or discomfort. Thus, a reduced number of DA receptors, due to carrying the DRD2 A1 allelic genotype, results in excessive craving behavior; whereas a normal or sufficient amount of DA receptors results in low craving behavior. In terms of preventing substance abuse, one goal would be to induce a proliferation of DA D2 receptors in genetically prone individuals. While in vivo experiments using a typical D2 receptor agonist induce down regulation, experiments in vitro have shown that constant stimulation of the DA receptor system via a known D2 agonist results in significant proliferation of D2 receptors in spite of genetic antecedents. In essence, D2 receptor stimulation signals negative feedback mechanisms in the mesolimbic system to induce mRNA expression causing proliferation of D2 receptors. Proposal and conclusion The authors propose that D2 receptor stimulation can be accomplished via the use of Synapatmine™, a natural but therapeutic nutraceutical formulation that potentially induces DA release, causing the same induction of D2-directed mRNA and thus proliferation of D2 receptors in the human. This proliferation of D2 receptors in turn will induce the attenuation of craving behavior. In fact as mentioned earlier, this model has been proven in research showing DNA-directed compensatory overexpression (a form of gene therapy) of the DRD2 receptors, resulting in a significant reduction in alcohol craving behavior in alcohol preferring rodents. Utilizing natural dopaminergic repletion therapy to promote long term dopaminergic activation will ultimately lead to a common, safe and effective modality to treat Reward Deficiency Syndrome (RDS) behaviors including Substance Use Disorders (SUD), Attention Deficit Hyperactivity Disorder (ADHD), Obesity and other reward deficient aberrant behaviors. This concept is further supported by the more comprehensive understanding of the role of dopamine in the NAc as a "wanting" messenger in the meso-limbic DA system. PMID:19014506

Blum, Kenneth; Chen, Amanda Lih Chuan; Chen, Thomas JH; Braverman, Eric R; Reinking, Jeffrey; Blum, Seth H; Cassel, Kimberly; Downs, Bernard W; Waite, Roger L; Williams, Lonna; Prihoda, Thomas J; Kerner, Mallory M; Palomo, Tomas; Comings, David E; Tung, Howard; Rhoades, Patrick; Oscar-Berman, Marlene

2008-01-01

321

The summit activity at Mt. Etna from 1995 to 2001: a multidisciplinary approach to investigate the long-term processes in the plumbing system  

NASA Astrophysics Data System (ADS)

The integration of volcanologic observations with petrologic, microgravity and ground deformation data acquired at Etna from 1995 to 2001, provide the opportunity to investigate the long-term dynamics of Mt. Etna during a period when the activity was restricted to the summit craters. Temporal patterns of major and trace elements indicate that the variability of bulk rocks composition is due to fractional crystallization and mixing between residing and new intruding magmas. Microgravity data show that from late-1996 to mid-1999 and from late-2000 to mid-2001, phases of strong gravity decrease occurred, centered on the upper southeastern sector of the volcano. The gravity decreases coincide with increases in the rate of the seismic strain release. Ground deformation show, from 1994 to the onset of the 2001 eruption, an almost continuous expansion of the volcano mainly due to magma accumulation into the western sector of the volcano. Therefore, the anti-correlation between gravity and seismicity in the eastern flank is not strictly connected to movements of magma and/or change of its chemical and physical properties. Conversely, these data suggest an increase of micro-fracturing along the NNW-SSE structural trend, implying a local density (gravity) decrease coupled with an increase in the release of seismic energy. From 1996 to 1999 the ascent of conspicuous magma volumes promoted the reactivation of the South-East and Voragine summit craters, that showed an intense explosive and effusive activity until the end of 1999. The increase in the rate of fracturing from late-2000 to mid-2001 enhanced the formation of a preferential path for magma ascent to the surface and the onset of the July 2001 flank eruption.

Carbone, Daniele; Corsaro, Rosa Anna; Guglielmino, Francesco; Puglisi, Giuseppe

2014-05-01

322

PKMf Maintains Spatial, Instrumental, and Classically Conditioned Long-Term  

Microsoft Academic Search

How long-term memories are stored is a fundamental question in neuroscience. The first molecular mechanism for long-term memory storage in the brain was recently identified as the persistent action of protein kinase Mzeta (PKMf), an autonomously active atypical protein kinase C (PKC) isoform critical for the maintenance of long-term potentiation (LTP). PKMf maintains aversively conditioned associations, but what general form

Eugenia L. Friedman; Jana Kenney; Stephen M. Taubenfeld; Joshua M. Zimmerman; John Hanna; Cristina Alberini; Ann E. Kelley; Stephen Maren; Jerry W. Rudy; Jerry C. P. Yin; Todd C. Sacktor; Andre A. Fenton

323

A Strategy to Conduct an Analysis of the Long-Term Performance of Low-Activity Waste Glass in a Shallow Subsurface Disposal System at Hanford  

SciTech Connect

Privatized services are being procured to vitrify low-activity tank wastes for eventual disposal in a shallow subsurface facility at the Hanford Site. Over 500,000 metric tons of low-activity waste glass will be generated, which is among the largest volumes of waste within the U.S. Department of Energy (DOE) complex and is one of the largest inventories of long-lived radionuclides planned for disposal in a low-level waste facility. Before immobilized waste can be disposed, DOE must approve a "performance assessment," which is a document that describes the impacts of the disposal facility on public health and environmental resources. Because the release rate of radionuclides from the glass waste form is a key factor determining these impacts, a sound scientific basis for determining their long-term release rates must be developed if this disposal action is to be accepted by regulatory agencies, stakeholders, and the public. In part, the scientific basis is determined from a sound testing strategy. The foundation of the proposed testing strategy is a well accepted mechanistic model that is being used to calculate the glass corrosion behavior over the geologic time scales required for performance assessment. This model requires that six parameters be determined, and the testing program is defined by an appropriate set of laboratory experiments to determine these parameters, and is combined with a set of field experiments to validate the model as a whole. Three general classes of laboratory tests are proposed in this strategy: 1) characterization, 2) accelerated, and 3) service condition. Characterization tests isolate and provide specific information about processes or parameters in theoretical models. Accelerated tests investigate corrosion behavior that will be important over the regulated service life of a disposal system within a laboratory time frame of a few years or less. Service condition tests verify that the techniques used in accelerated tests do not change the alteration mechanisms. The recommended characterization tests are single-pass flow-through tests using a batch reactor design, Accelerated and service conditions tests include product consistency and pressurized unsaturated flow (PUF) tests. Nonradioactive glasses will be used for the majority of the laboratory testing (-80%), with the remainder performed with glasses containing a selected set of key radionuclides. Additionally, a series of PUF experiments with a natural analog of basaltic glass is recommended to confirm that the alteration products observed under accelerated conditions in the PUF tests are similar to those found associated with the natural analog. This will provide additional confidence in using the PUF test results to infer long-term corrosion behavior. Field tests are proposed as a unique way to validate the glass corrosion and contaminant transport models being used in the performance assessment. To better control the test conditions, the field tests are to be performed in lysimeters (corrugated steel containers buried flush with the ground surface). Lysimeters provide a way to combine a glass, Hanford soil, and perhaps other engineered materials in a well-controlled test, but on a scale that is not practicable in the laboratory. The recommended field tests include some experiments where a steady flow rate of water is artificially applied. These tests use a glass designed to have a high corrosion rate so that it is easier to monitor contaminant release and transport. Existing lysimeters at the Hanford Site can be used for these experiments or new lysimeters that have been equipped with the latest in monitoring equipment and located near the proposed disposal site.

BP McGrail, WL Ebert, DH Bacon, DM Strachan

1998-02-18

324

Inhibition of PKC-dependent extracellular Ca2+ entry contributes to the depression of contractile activity in long-term pressure-overloaded endothelium-denuded rat aortas  

PubMed Central

We examined the contractile responsiveness of rat thoracic aortas under pressure overload after long-term suprarenal abdominal aortic coarctation (lt-Srac). Endothelium-dependent angiotensin II (ANG II) type 2 receptor (AT2R)-mediated depression of contractions to ANG II has been reported in short-term (1 week) pressure-overloaded rat aortas. Contractility was evaluated in the aortic rings of rats subjected to lt-Srac or sham surgery (Sham) for 8 weeks. ANG I and II levels and AT2R protein expression in the aortas of lt-Srac and Sham rats were also evaluated. lt-Srac attenuated the contractions of ANG II and phenylephrine in the aortas in an endothelium-independent manner. However, lt-Srac did not influence the transient contractions induced in endothelium-denuded aortic rings by ANG II, phenylephrine, or caffeine in Ca2+-free medium or the subsequent tonic constrictions induced by the addition of Ca2+ in the absence of agonists. Thus, the contractions induced by Ca2+ release from intracellular stores and Ca2+ influx through stored-operated channels were not inhibited in the aortas of lt-Srac rats. Potassium-elicited contractions in endothelium-denuded aortic rings of lt-Srac rats remained unaltered compared with control tissues. Consequently, the contractile depression observed in aortic tissues of lt-Srac rats cannot be explained by direct inhibition of voltage-operated Ca2+ channels. Interestingly, 12-O-tetradecanoylphorbol-13-acetate-induced contractions in endothelium-denuded aortic rings of lt-Srac rats were depressed in the presence but not in the absence of extracellular Ca2+. Neither levels of angiotensins nor of AT2R were modified in the aortas after lt-Srac. The results suggest that, in rat thoracic aortas, lt-Srac selectively inhibited protein kinase C-mediated activation of contraction that is dependent on extracellular Ca2+ entry. PMID:25098618

Padilla, J.; López, R.M.; López, P.; Castillo, M.C.; Querejeta, E.; Ruiz, A.; Castillo, E.F.

2014-01-01

325

Long-term reduction of cocaine self-administration in rats treated with adenoviral vector-delivered cocaine hydrolase: evidence for enzymatic activity.  

PubMed

A new pharmacokinetic approach treating cocaine addiction involves rapidly metabolizing cocaine before it reaches brain reward centers using mutated human butyrylcholinesterase (BChE) or cocaine hydrolase (CocH). Recent work has shown that helper-dependent adenoviral (hdAD) vector-mediated plasma CocH reduced the locomotor-activating effects of cocaine and prevented reinstatement of cocaine-seeking behavior up to 6 months in rats. The present study investigated whether hdAD-CocH could decrease ongoing intravenous cocaine (0.4 mg/kg) self-administration. The hdAD-CocH vector was injected into self-administering rats, and after accumulation of plasma CocH, there was a dramatic reduction in cocaine infusions earned under a fixed ratio 1 schedule of reinforcement that lasted for the length of the study (>2 months). Pretreatment with the selective BChE and CocH inhibitor iso-OMPA (1.5 mg/kg) restored cocaine intake; therefore, the decline in self-administration was likely due to rapid CocH-mediated cocaine metabolism. Direct measurements of cocaine levels in plasma and brain samples taken after the conclusion of behavioral studies provided strong support for this conclusion. Further, rats injected with hdAD-CocH did not experience a deficit in operant responding for drug reinforcement and self-administered methamphetamine (0.05 mg/kg) at control levels. Overall, these outcomes suggest that viral gene transfer can yield plasma CocH levels that effectively diminish long-term cocaine intake and may have potential treatment implications for cocaine-dependent individuals seeking to become and remain abstinent. PMID:24407266

Zlebnik, Natalie E; Brimijoin, Stephen; Gao, Yang; Saykao, Amy T; Parks, Robin J; Carroll, Marilyn E

2014-05-01

326

Long-term data archiving  

SciTech Connect

Long term data archiving has much value for chemists, not only to retain access to research and product development records, but also to enable new developments and new discoveries. There are some recent regulatory requirements (e.g., FDA 21 CFR Part 11), but good science and good business both benefit regardless. A particular example of the benefits of and need for long term data archiving is the management of data from spectroscopic laboratory instruments. The sheer amount of spectroscopic data is increasing at a scary rate, and the pressures to archive come from the expense to create the data (or recreate it if it is lost) as well as its high information content. The goal of long-term data archiving is to save and organize instrument data files as well as any needed meta data (such as sample ID, LIMS information, operator, date, time, instrument conditions, sample type, excitation details, environmental parameters, etc.). This editorial explores the issues involved in long-term data archiving using the example of Raman spectral databases. There are at present several such databases, including common data format libraries and proprietary libraries. However, such databases and libraries should ultimately satisfy stringent criteria for long term data archiving, including readability for long times into the future, robustness to changes in computer hardware and operating systems, and use of public domain data formats. The latter criterion implies the data format should be platform independent and the tools to create the data format should be easily and publicly obtainable or developable. Several examples of attempts at spectral libraries exist, such as the ASTM ANDI format, and the JCAMP-DX format. On the other hand, proprietary library spectra can be exchanged and manipulated using proprietary tools. As the above examples have deficiencies according to the three long term data archiving criteria, Extensible Markup Language (XML; a product of the World Wide Web Consortium, an independent standards body) as a new data interchange tool is being investigated and implemented. In order to facilitate data archiving, Raman data needs calibration as well as some other kinds of data treatment. Figure 1 illustrates schematically the present situation for Raman data calibration in the world-wide Raman spectroscopy community, and presents some of the terminology used.

Moore, David Steven [Los Alamos National Laboratory

2009-01-01

327

Soil organic carbon (SOC) accumulation in rice paddies under long-term agro-ecosystem experiments in southern China - VI. Changes in microbial community structure and respiratory activity  

NASA Astrophysics Data System (ADS)

Biological stabilization within accumulated soil organic carbon (SOC) has not been well understood, while its role in physical and chemical protection as well as of chemical recalcitrance had been addressed in Chinese rice paddies. In this study, topsoil samples were collected and respiratory activity measured in situ following rice harvest under different fertilization treatments of three long-term experimental sites across southern China in 2009. The SOC contents, microbial biomass carbon (SMBC) and nitrogen (SMBN) were analysed using chemical digestion and microbial community structure assessment via clony dilute plate counting methods. While SOC contents were consistently higher under compound chemical fertilization (Comp-Fert) or combined organic and inorganic fertilization (Comb-Fert) compared to N fertilization only (N-Fert), there was significantly higher fungal-bacterial ratio under Comb-Fert than under N-Fert and Comp-Fert. When subtracting the background effect under no fertilization treatment (Non-Fert), the increase both in SMBC and SMBN under fertilization treatment was found very significantly correlated to the increase in SOC over controls across the sites. Also, the ratio of culturable fungal to bacterial population numbers (F/B ratio) was well correlated with soil organic carbon contents in all samples across the sites studied. SOC accumulation favoured a build-up the microbial community with increasing fungal dominance in the rice paddies under fertilization treatments. While soil respiration rates were high under Comb-Fert as a result of enhanced microbial community build-up, the specific soil respiratory activity based on microbial biomass carbon was found in a significantly negatively correlation with the SOC contents for overall samples. Thus, a fungal-dominated microbial community seemed to slow SOC turnover, thereby favouring SOC accumulation under Comp-Fert or under Comb-Fert in the rice paddies. Therefore, the biological stabilization process is of importance in SOC sequestration in the rice paddies, operating with physical and chemical protection and chemical recalcitrance. However, sufficient understanding and prediction of SOM dynamics needs further quantitative characterization of the simultaneous operation of several mechanisms.

Liu, D.; Liu, X.; Liu, Y.; Li, L.; Pan, G.; Crowley, D.; Tippkötter, R.

2011-02-01

328

Modelling the effects of solar activity onto the Greek national electric grid  

NASA Astrophysics Data System (ADS)

We study both the short term and long term effects of solar activity on the large transformers (150kV and 400kV) of the Greek national electric grid. We use data analysis and various analytic and statistical methods and models. Contrary to the common belief in PPC Greece, we see that there are considerable both short term (immediate) and long term effects of solar activity onto large transformers in a mid-latitude country like Greece. Our results can be summarized as follows: For the short term effects: During 1989-2010 there were 43 "stormy days" (namely days with for example Ap >= 100) and we had 19 failures occurring during a stormy day plus or minus 3 days and 51 failures occurring during a stormy day plus or minus 7 days. All these failures can be directly related to Geomagnetically Induced Currents (GIC's). Explicit cases are presented. For the long term effects we have two main results: The maximum number of transformer failures occur 3-4 years after the maximum of solar activity. There is statistical correlation between solar activity expressed using various newly defined long term solar activity indices and the annual number of transformer failures. These new long term solar activity indices were defined using both local (from geomagnetic stations in Greece) and global (planetary averages) geomagnetic data. Applying both linear and non-linear statistical regression we compute the regression equations and the corresponding coefficients of determination.

Zois, I. P.

2014-03-01

329

Solar Terrestrial Activity Report  

NSDL National Science Digital Library

This chock-full of data page is hosted by the DX-listeners club (folks who search for distant radio signals). At the top is a graph of solar flux, sunspot number, and planetary A index, measured every five days, from October 30, 2000 to the present. Next come links to more data and graphs on solar energy, cycles, etc. Recent Solar and Geomagnetic Data, Solar Wind, and Electron Fluence Charts are updated daily. Also on-site are data for Solar Cycles 1-23; a Graphical Comparison of Cycles 21, 22 and 23; a Graphical Comparison of Cycles 10, 13, 17, 20 and 23; and Historical Solar and Geomagnetic data charts 1954-2000. In addition, users will find data and data links including active solar region maps, geomagnetic forecasts, and reports of recent solar activities such as flares and coronal mass injections.

330

Long-term potentiation in the hippocampus.  

PubMed

Long-term potentiation of field and single neuronal responses recorded in various hippocampal fields is described on the basis of author's and literary data. Most of intrahippocampal and extrinsic connections in both in vivo and in vitro hippocampal preparations show this phenomenon after one or several conditioning trains of comparatively short duration (20 s or less) at various frequencies (from 10 to 400 Hz). Properties of hippocampal potentiation are described. The properties include long term persistence (hours and days) of the potentiated response, its low frequency depression, self-restoration after the depression, specificity of the potentiation for the tetanized pathway, necessity of activation of a sufficient number of neuronal elements ('cooperativity') to produce the potentiation, possible involvement of 'reinforcing' brain structures during conditioning tetanization. These properties are distinct from those of 'usual' short-term post-tetanic potentiation and lead to the suggestion that the neuronal mechanisms underlying long-term post-tetanic are similar to those underlying memory and behavioral-conditioned reflex. Neurophysiological mechanisms of long-term potentiation are discussed. The main mechanism consists in an increase in efficacy of excitatory synapses as shown by various methods including intracellular recording and quantal analysis. The latter favours presynaptic localization of changes of synaptic efficacy showing increase in the number of transmitter quanta released per presynaptic impulse. However, changes in the number of subsynaptic receptors or localized changes in dendritic postsynaptic membrane are not excluded. Biochemical studies indicate the increase in transmitter release and calcium-dependent phosphorylation of pyruvate dehydrogenase after tetanization. Instances of persistent response facilitations at other levels of the vertebrate central nervous system (especially at neocortical level) are considered and compared with hippocampal long-term potentiation. It is suggested that modifiable excitatory synapses necessary for learning have been identified in studies of long-term potentiation. These synapses are presumably modified as a result of close sequential activation of the following three structures: excitatory presynaptic fibers, the postsynaptic neuron and a 'reinforcing' brain system. PMID:6141538

Voronin, L L

1983-12-01

331

Adolescent political activism and long-term happiness: a 21-year longitudinal study on the development of micro- and macrosocial worries.  

PubMed

Utilizing latent growth modeling, the long-term development of worries among peace movement supporters is examined. Data originate from a seven-wave German longitudinal study started in 1985 with on average 14-year-olds. Waves were interspersed 3 and a half years each. Activists are assumed to have lower (self-related) microworries (Hypothesis 1) and higher macroworries (concerned with larger entities; Hypothesis 2) than nonactivists at the onset of the study. Nonactivists who appraised the threat of nuclear war as high in 1985 are assumed to report worse mental health than their activist age-mates 21 years later (Hypothesis 3). Activists are assumed to express relatively more macroworries than nonactivists in midadulthood (Hypothesis 4). All four hypotheses were confirmed. Results are interpreted in a stress-coping (Lazarus) and resource (Elder) framework, suggesting that refraining from acting out against a perceived sociopolitical threat is a long-term risk for a positive mental health trajectory. PMID:21307181

Boehnke, Klaus; Wong, Becky

2011-03-01

332

The Fall and Rise of V854 Centauri: Long-Term Ultraviolet Spectroscopy of a Highly Active R Coronae Borealis Star  

Microsoft Academic Search

We examine long-term low-dispersion International Ultraviolet Explorer SWP and LWP spectroscopy of the R Coronae Borealis (RCB) star V854 Cen, obtained across the deep (DeltaV>6 mag) 1991, 1992-1993, and 1994 declines. We also report the optical light curve for the star in the interval 1987-1998, including multicolor photometry obtained during 1989-1998. The light curve includes at least eight major declines

Warrick A. Lawson; Marco M. Maldoni; Geoffrey C. Clayton; Lynne Valencic; Albert F. Jones; David Kilkenny; Francois van Wyk; Greg Roberts; Fred Marang

1999-01-01

333

Diversity and Activity of Cellulose-Decomposing Bacteria, Isolated from a Sandy and a Loamy Soil after Long-Term Manure Application  

Microsoft Academic Search

The community of culturable cellulolytic bacteria was analyzed in two long-term experimental field sites on Albic Luvisol\\u000a (silty sand) and Haplic Phaeozem (loam), with and without farmyard manure treatment. Against the backdrop of significant differences\\u000a in soil properties, the bacterial community structure differed clearly between sites and was affected by manure application\\u000a as analyzed by T-RFLP of 16S rDNA. The

Andreas Ulrich; Gabriele Klimke; Stephan Wirth

2008-01-01

334

Did Open Solar Magnetic Field Increase During The Last 100 Years? A Reanalysis of Geomagnetic Activity  

Microsoft Academic Search

Long-term geomagnetic activity presented by the aa index has been used to show that the heliospheric magnetic field has more than doubled during the last 100 years. However,\\u000a serious concern has been raised on the long-term consistency of the aa index and on the centennial rise of the solar magnetic field. Here we reanalyze geomagnetic activity during the last 100

K. Mursula; D. Martini; A. Karinen

2004-01-01

335

Solar Week 2001 Activities  

NSDL National Science Digital Library

This resource offers a week of online curriculum with daily topics on the Sun, including Sun as a Star, the Sun Close Up, Solar Activity, Eclipses, and Careers organized for Solar Week 2011. Each day contains a game, an activity, topical questions, a related Life Science topic, teacher information, and an Ask the Scientist page.

2001-03-01

336

Involvement of high plasma corticosterone status and activation of brain regional serotonin metabolism in long-term erythrosine-induced rearing motor hyper activity in young adult male rats.  

PubMed

Long-term consumption of artificial food color(s) can induce behavioral hyperactivity in human and experimental animals, but no neurobiochemical mechanism is defined. This study investigates the role of brain regional serotonin metabolism including its turnover, MAO-A activity, and plasma corticosterone status in relation to behavioral disturbances due to an artificial food color, erythrosine. Long-term (15 or 30 consecutive days) erythrosine administration with higher dosage (10 or 100 mg/kg/day, p.o.) produced optimal hyperactive state in exploratory behavior (rearing motor activity) after 2 h of last erythrosine administration, in young adult male albino rats. Erythrosine-induced stimulation in brain regional (medulla-pons, hypothalamus, hippocampus, and corpus striatum) serotonin metabolism (measuring steady state levels of 5-HT and 5-HIAA, MAO-A activity), including its turnover (pargyline-induced 5-HT accumulation and 5-HIAA declination rate), as well as plasma corticosterone were also observed depending on dosage(s) and duration(s) of erythrosine administration under similar experimental conditions. The lower dosage of erythrosine (1 mg/kg/day, p.o.) under similar conditions did not affect either of the above. These findings suggests (a) the induction as well as optimal effect of long-term erythrosine (artificial food color) on behavioral hyperactivity in parallel with increase in 5-HT level in brain regions, (b) the activation of brain regional serotonin biosynthesis in accordance with plasma corticosterone status under such behavioral hyperactivity, and (c) a possible inhibitory influence of the enhanced glucocorticoids-serotonin interaction on erythrosine-induced rearing motor hyperactivity in young adult mammals. PMID:20465369

Dalal, Arindam; Poddar, Mrinal K

2010-07-01

337

Stabilizing chromophore binding on TiO2 for long-term stability of dye-sensitized solar cells using multicomponent atomic layer deposition.  

PubMed

Ambient humidity and high temperature are known to degrade dye-sensitized solar cells (DSSCs) via chromophore desorption. Recently, enhanced dye-attachment to TiO2 surfaces has been realized by coating molecularly functionalized surfaces with inorganic atomic layer deposition (ALD) coatings. Here, we apply this ALD approach to DSSCs and demonstrate that high energy conversion efficiencies can be maintained while significantly extending device lifetimes. While single component ALD layers show improved high-temperature stability, it significantly degraded up to 45% of initial DSSC performance right after ALD. We, however, find that mixed component ALD layers provide initial efficiencies within 90% of their untreated counterparts while still extending device lifetimes. Optimized ALD protection schemes maintain 80% of their initial efficiency after 500 h of thermal aging at 80 °C whereas efficiency of DSSCs with no ALD protection drop below 60% of their initial efficiencies. IR spectroscopy conducted in situ during ALD reveals that carboxylate linker groups transition from unbound or weakly-bound states, respectively, to more strongly bound bidentate structures. This strategy to improve dye-attachment by ALD while maintaining high performance is novel and promising for extending the functional lifetime for DSSCs and other related devices. PMID:24676056

Kim, Do Han; Losego, Mark D; Hanson, Kenneth; Alibabaei, Leila; Lee, Kyoungmi; Meyer, Thomas J; Parsons, Gregory N

2014-05-14

338

Petrophysical characterization of first ever drilled core samples from an active CO2 storage site, the German Ketzin Pilot Site - Comparison with long term experiments  

NASA Astrophysics Data System (ADS)

Petrophysical properties like porosity and permeability are key parameters for a safe long-term storage of CO2 but also for the injection operation itself. These parameters may change during and/or after the CO2 injection due to geochemical reactions in the reservoir system that are triggered by the injected CO2. Here we present petrophysical data of first ever drilled cores from a newly drilled well at the active CO2 storage site - the Ketzin pilot site in the Federal State of Brandenburg, Germany. By comparison with pre-injection baseline data from core samples recovered prior to injection, the new samples provide the unique opportunity to evaluate the impact of CO2 on pore size related properties of reservoir and cap rocks at a real injection site under in-situ reservoir conditions. After injection of 61 000 tons CO2, an additional well was drilled and new rock cores were recovered. In total 100 core samples from the reservoir and the overlaying caprock were investigated by NMR relaxation. Permeability of 20 core samples was estimated by nitrogen and porosity by helium pycnometry. The determined data are comparable between pre-injection and post-injection core samples. The lower part of the reservoir sandstone is unaffected by the injected CO2. The upper part of the reservoir sandstone shows consistently slightly lower NMR porosity and permeability values in the post-injection samples when compared to the pre-injection data. This upper sandstone part is above the fluid level and CO2 present as a free gas phase and a possible residual gas saturation of the cores distorted the NMR results. The potash-containing drilling fluid can also influence these results: NMR investigation of twin samples from inner and outer parts of the cores show a reduced fraction of larger pores for the outer core samples together with lower porosities and T2 times. The drill mud penetration depth can be controlled by the added fluorescent tracer. Due to the heterogeneous character of the Stuttgart Formation it is difficult to estimate definite CO2 induced changes from petrophysical measurements. The observed changes are only minor. Several batch experiments on Ketzin samples drilled prior injection confirm the results from investigation of the in-situ rock cores. Core samples of the pre-injection wells were exposed to CO2 and brine in autoclaves over various time periods. Samples were characterized prior to and after the experiments by NMR and Mercury Injection Porosimetry (MIP). The results are consistent with the logging data and show only minor change. Unfortunately, also in these experiments observed mineralogical and petrophysical changes were within the natural heterogeneity of the Ketzin reservoir and precluded unequivocal conclusions. However, given the only minor differences between post-injection well and pre-injection well, it is reasonable to assume that the potential dissolution-precipitation processes appear to have no severe consequences on reservoir and cap rock integrity or on the injection behaviour. This is also in line with the continuously recorded injection operation parameter. These do not point to any changes in reservoir injectivity.|

Zemke, Kornelia; Liebscher, Axel

2014-05-01

339

Long-term oxygen therapy.  

PubMed

This article provides an overview of the status of long-term oxygen therapy (LTOT). In the United States, payment cutbacks are occurring as a result of congressionally mandated competitive bidding and capped rental programs. These Medicare programs are discussed. These legislative and regulatory changes may result in reduced patient access to appropriate oxygen-delivery systems that meet medical needs, including optimal ambulation. Prescribing LTOT is addressed in this article, as is the need for adequate patient education. The importance of appropriate monitoring and reassessment is presented. The use of an LTOT collaborative care model is discussed. Although the new intermittent flow oxygen-delivery systems have potential benefits, there is consensus that each patient should be tested on the specific device because of variability in delivery and patient response. Feasible locations for patient education and monitoring are identified. PMID:21285057

Christopher, Kent L; Porte, Phillip

2011-02-01

340

Final Activity Report: The Effects of Iron Complexing Ligands on the Long Term Ecosystem Response to Iron Enrichment of HNLC waters  

SciTech Connect

Substantial increases in the concentrations of the stronger of two Fe(III) complexing organic ligand classes measured during the mesoscale Fe enrichment studies IronEx II and SOIREE appeared to sharply curtailed Fe availability to diatoms and thus limited the efficiency of carbon sequestration to the deep. Detailed observations during IronEx II (equatorial Pacific Ocean) and SOIREE (Southern Ocean –Pacific sector) indicate that the diatoms began re-experiencing Fe stress even though dissolved Fe concentrations remained elevated in the patch. This surprising outcome likely is related to the observed increased concentrations of strong Fe(III)-complexing ligands in seawater. Preliminary findings from other studies indicate that diatoms may not readily obtain Fe from these chemical species whereas Fe bound by strong ligands appears to support growth of cyanobacteria and nanoflagellates. The difficulty in assessing the likelihood of these changes with in-situ mesoscale experiments is the extended monitoring period needed to capture the long-term trajectory of the carbon cycle. A more detailed understanding of Fe complexing ligand effects on long-term ecosystem structure and carbon cycling is essential to ascertain not only the effect of Fe enrichment on short-term carbon sequestration in the oceans, but also the potential effect of Fe enrichment in modifying ecosystem structure and trajectory.

Trick, Charles Gordon [Western University

2013-07-30

341

Long-term plasticity may be manifested as reduction or expansion of cortical representations of actively used muscles in motor skill specialists.  

PubMed

Our aim was to study long-term plasticity in the organization of cortical muscle representations due to extensive motor training for different skills. We were especially interested in whether skill-specific demands on independent hand muscle movements and synchronous leg muscle movements are reflected differently in the reorganization of muscle representations. We used navigated transcranial magnetic stimulation to estimate the size of cortical representations of opponens pollicis, abductor digiti minimi, and tibialis anterior muscles in five string instrument players, five figure skaters, and five controls. The extent of the representation area was presented as an amplitude-area curve showing the spatial distribution of motor evoked potentials. The size of representation areas was compared between the dominant and nondominant hemispheres and between the groups. The representation area of the left abductor digiti minimi (critical for reaching right tones) in the right, nondominant hemisphere was smaller in string players and the representation area of the tibialis anterior in the dominant hemisphere (critical for jumps) was larger in figure skaters when compared with controls. Reorganization in the motor cortex may differ depending upon the skill and an individual muscle's role in the skill. A smaller representation area of the independently used hand muscle in masters of fine motor skills may reflect long-term plasticity toward more focused representation, which may be beneficial in accurate and discrete cortical control of the muscle. Larger cortical representations are related to skill demanding coactivation of proximal and distal lower limb muscles. PMID:23719022

Vaalto, Selja; Julkunen, Petro; Säisänen, Laura; Könönen, Mervi; Määttä, Sara; Karhu, Jari

2013-08-01

342

Systemic Administration of Atipamezole, a Selective Antagonist of Alpha2 Adrenoceptors, Facilitates Behavioural Activity but does not Influence Short-term or Long-term Memory in Trimethyltin-intoxicated and Control Rats  

Microsoft Academic Search

NIITTYKOSKI M., R. LAPPALAINEN, J. JOLKKONEN, A. HAAPALINNA, P. RIEKKINEN Sr and J. SIRVIÖ. Systemic administration of atipamezole, a selective antagonist of alpha-2 adrenoceptors, facilitates behavioural activity but does not influence short-term or long-term memory in trimethyltin-intoxicated and control rats. NEUROSCI BIOBEHAV REV 22(6) 735–750, 1998.—The present study used trimethyltin (TMT)-intoxicated rats as a model for the behavioural syndrome seen

M Niittykoski; R Lappalainen; J Jolkkonen; A Haapalinna; P Riekkinen; J Sirviö

1998-01-01

343

Long-term effects of 6-week whole-body vibration on balance recovery and activities of daily living in the postacute phase of stroke: a randomized, controlled trial  

Microsoft Academic Search

BACKGROUND AND PURPOSE: The long-term effects of 6-weeks whole-body vibration, as a novel method of somatosensory stimulation, on postural control and activities of daily living were compared with those of 6 weeks of exercise therapy on music of the same intensity in the postacute phase of stroke. METHODS: Fifty-three patients with moderate to severe functional disabilities were randomized within 6

I. J. W. van Nes; H. Latour; F. Schils; R. Meijer; A. van Kuijk; A. C. H. Geurts

2006-01-01

344

Antifungal activity of Meyerozyma guilliermondii: identification of active compounds synthesized during dough fermentation and their effect on long-term storage of wheat bread.  

PubMed

Preliminarily, 146 strains of yeasts were screened for the antifungal activity toward the indicator Penicillium roqueforti DPPMAF1. The strain Meyerozyma guilliermondii LCF1353 was selected and used for dough fermentation. The water/salt soluble extract of the dough was analyzed by HPLC and GC/MS-SPME. The synthesis of the extracellular cell wall-degrading enzyme ?-1,3-glucanase and ethyl-acetate was shown. The effect on conidia germination mainly suggested a fungistatic activity. M. guilliermondii LCF1353 was used as starter for dough fermentation in combination with Wickeramomyces anomalus 1695 and Lactobacillus plantarum 1A7, which were previously selected for antifungal activity. The growth of the strains was monitored by plate count and molecular techniques, and competitive or antagonistic interactions among them were excluded. Bread started with the combination of M. guilliermondii LCF1353, W. anomalus LCF1695 and L. plantarum 1A7 showed a more prolonged shelf life compared to the other breads. Fungal growth was delayed at least until 14 days of storage, under conditions of high artificial inoculum. The bread manufactured with the above combination showed good chemical and textural characteristics and, as shown by sensory analysis, it was appreciated for elasticity, color and taste. PMID:23200658

Coda, Rossana; Rizzello, Carlo G; Di Cagno, Raffaella; Trani, Antonio; Cardinali, Gianluigi; Gobbetti, Marco

2013-04-01

345

Long-term evolution of transposable elements  

PubMed Central

Transposable elements are often considered parasitic DNA sequences, able to invade the genome of their host thanks to their self-replicating ability. This colonization process has been extensively studied, both theoretically and experimentally, but their long-term coevolution with the genomes is still poorly understood. In this work, we aim to challenge previous population genetics models by considering features of transposable elements as quantitative, rather than discrete, variables. We also describe more realistic transposable element dynamics by accounting for the variability of the insertion effect, from deleterious to adaptive, as well as mutations leading to a loss of transposition activity and to nonautonomous copies. Individual-based simulations of the behavior of a transposable-element family over several thousand generations show different ways in which active or inactive copies can be maintained for a very long time. Results reveal an unexpected impact of genetic drift on the “junk DNA” content of the genome and strongly question the likelihood of the sustainable long-term stable transposition-selection equilibrium on which numerous previous works were based. PMID:18040048

Le Rouzic, Arnaud; Boutin, Thibaud S.; Capy, Pierre

2007-01-01

346

A new method to estimate annual solar wind parameters and contributions of different solar wind structures to geomagnetic activity  

NASA Astrophysics Data System (ADS)

In this paper, we study two sets of local geomagnetic indices from 26 stations using the principal component and the independent component (IC) analysis methods. We demonstrate that the annually averaged indices can be accurately represented as linear combinations of two first components with weights systematically depending on latitude. We show that the annual contributions of coronal mass ejections (CMEs) and high-speed streams (HSSs) to geomagnetic activity are highly correlated with the first and second IC. The first and second ICs are also found to be very highly correlated with the strength of the interplanetary magnetic field (IMF) and the solar wind speed, respectively, because solar wind speed is the most important parameter driving geomagnetic activity during HSSs while IMF strength dominates during CMEs. These results help in better understanding the long-term driving of geomagnetic activity and in gaining information about the long-term evolution of solar wind parameters and the different solar wind structures.

Holappa, L.; Mursula, K.; Asikainen, T.

2014-12-01

347

Functional titanium oxide nano-particles as electron lifetime, electrical conductance enhancer, and long-term performance booster in quasi-solid-state electrolyte for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

This research investigates the design of a quasi-solid-state electrolyte for improving the photovoltaic efficiency and long-term performance stability of dye-sensitized solar cells (DSSCs). In this study, agarose gel and titanium oxide (TiO2) nano-particles are incorporated into an iodine/iodide electrolyte solution in a 1-methyl-2-pyrrolidinone (NMP)/3-methoxypropionitrile (MPN) solvent mixture to fabricate quasi-solid-state electrolytes for 2.0-cm2 DSSCs. The electrolyte also contains an ionic liquid, 1-methyl-3-propylimidazolium iodide, and a co-additive, 1-methylbenzimidazole. The negatively charged TiO2 nano-particles exhibit an anatase crystal structure. Without agarose and TiO2, the control cell's photovoltaic efficiency drops by more than 50% over 2400 h of aging due to a significant decrease in the short-circuit current. Incorporating 1% agarose into the electrolyte not only enhances the retention of the solvent but also maintains the short-circuit current. Furthermore, adding 0.5% TiO2 to 1% agarose electrolyte provides sufficient ion and electron transfer routes and improves the fill factor of the corresponding DSSC. The photoconversion efficiency of the agarose/TiO2-containing DSSC monotonically increases from an initial value of 5.08% to 6.48% within 2400 h. The improved cell efficiency is correlated to the longer electron lifetime in the DSSC, higher ion diffusivity, and the smaller electrical resistance of the electrolyte.

Lue, Shingjiang Jessie; Wu, Yun-Ling; Tung, Yung-Liang; Shih, Chao-Ming; Wang, Yi-Chun; Li, Jun-Ruei

2015-01-01

348

A long-term solution to fossil fuel depletion  

Microsoft Academic Search

It is argued that the only long-term practical alternative to sustaining a national economy on organic fuels is to convert a major source of continuously renewable nonfossil carbon to synfuels that are interchangeable with fossil fuels. The most promising source of this carbon is land- and water-based biomass produced from solar energy by photosynthesis. This paper presents an assessment of

D. L. Klass

1976-01-01

349

The fall and rise of V854 Centauri: long-term ultraviolet spectroscopy of a highly-active R Coronae Borealis star  

E-print Network

We examine long-term low-dispersion IUE, SWP and LWP spectroscopy of the R Coronae Borealis (RCB) star V854 Cen, obtained across the deep 1991, 1992-1993 and 1994 declines. We also report the optical light curve for the star in the interval 1987-1998, including multi-color photometry obtained during 1989-1998. Analysis of the UV emission line spectra indicates most lines decay during the deep declines on characteristic timescales comparable to that reported for optical features. Fe, Mg and neutral C lines decay on timescales of typically 50-100 d. Other lines, notably ionized C lines, decay on longer timescales (> 200 d) or appear to be unaffected by the declines. The general nature of the UV emission lines and other UV features during the declines is consistent with the E1/E2/BL line-region model developed from the behavior of optical spectral features during declines. However, the detailed line-behavior indicates large intrinsic variability between decline events inconsistent with the simple E1/E2/BL model. Limited temporal coverage prevents detailed examination of the geometry of the emission line region or the obscuring dust. We also report the first detection of the transition-region line C IV 1550 in the spectrum of an RCB star.

W. A. Lawson

1999-05-18

350

Physics of solar activity  

NASA Technical Reports Server (NTRS)

The aim of the research activity was to increase our understanding of solar activity through data analysis, theoretical analysis, and computer modeling. Because the research subjects were diverse and many researchers were supported by this grant, a select few key areas of research are described in detail. Areas of research include: (1) energy storage and force-free magnetic field; (2) energy release and particle acceleration; (3) radiation by nonthermal electrons; (4) coronal loops; (5) flare classification; (6) longitude distributions of flares; (7) periodicities detected in the solar activity; (8) coronal heating and related problems; and (9) plasma processes.

Sturrock, Peter A.

1993-01-01

351

The neuronal response at extended timescales: long-term correlations without long-term memory  

PubMed Central

Long term temporal correlations frequently appear at many levels of neural activity. We show that when such correlations appear in isolated neurons, they indicate the existence of slow underlying processes and lead to explicit conditions on the dynamics of these processes. Moreover, although these slow processes can potentially store information for long times, we demonstrate that this does not imply that the neuron possesses a long memory of its input, even if these processes are bidirectionally coupled with neuronal response. We derive these results for a broad class of biophysical neuron models, and then fit a specific model to recent experiments. The model reproduces the experimental results, exhibiting long term (days-long) correlations due to the interaction between slow variables and internal fluctuations. However, its memory of the input decays on a timescale of minutes. We suggest experiments to test these predictions directly. PMID:24744724

Soudry, Daniel; Meir, Ron

2014-01-01

352

Hydrosolidarity intergenerational challenges: long-term commitment for long-term issues.  

PubMed

The year 2000 Young Professionals Seminar focused on long-term intergenerational challenges. Water related problems are symptoms of complex and ultimately societal problems linked to human behaviour, political support and managerial and institutional structures. Although integrated water resources management is presented as a solution, it is not always well understood, and can create a sense of hopelessness among professionals. To make it operational requires long-term commitments among various professionals and the involvement of new actors. A number of key topics crystallised as needing further attention, including ethical dimensions in policy making, the development of a framework for a "Future Generation Impact Assessment" (FGIA), and efforts to achieve true dialogue among stakeholders. Young water professionals must become more involved in political processes and take active part in institutional changes. Such engagement will require changes in the working environment facing many young professionals that causes frustration due to inefficient and conservative hierarchical structures and the lack of transparency. PMID:11379221

Kuylenstierna, J; Rockström, J

2001-01-01

353

Exposure to Ionizing Radiation Causes Long-Term Increase in Serum Estradiol and Activation of PI3K-Akt Signaling Pathway in Mouse Mammary Gland  

SciTech Connect

Purpose: Exposure to ionizing radiation is an established risk factor for breast cancer. Radiation exposure during infancy, childhood, and adolescence confers the highest risk. Although radiation is a proven mammary carcinogen, it remains unclear where it acts in the complex multistage process of breast cancer development. In this study, we investigated the long-term pathophysiologic effects of ionizing radiation at a dose (2 Gy) relevant to fractionated radiotherapy. Methods and Materials: Adolescent (6-8 weeks old; n = 10) female C57BL/6J mice were exposed to 2 Gy total body {gamma}-radiation, the mammary glands were surgically removed, and serum and urine samples were collected 2 and 12 months after exposure. Molecular pathways involving estrogen receptor-{alpha} (ER{alpha}) and phosphatidylinositol-3-OH kinase (PI3K)-Akt signaling were investigated by immunohistochemistry and Western blot. Results: Serum estrogen and urinary levels of the oncogenic estrogen metabolite (16{alpha}OHE1) were significantly increased in irradiated animals. Immunostaining for the cellular proliferative marker Ki-67 and cyclin-D1 showed increased nuclear accumulation in sections of mammary glands from irradiated vs. control mice. Marked increase in p85{alpha}, a regulatory sub-unit of the PI3K was associated with increase in Akt, phospho-Akt, phospho-BAD, phospho-mTOR, and c-Myc in irradiated samples. Persistent increase in nuclear ER{alpha} in mammary tissues 2 and 12 months after radiation exposure was also observed. Conclusions: Taken together, our data not only support epidemiologic observations associating radiation and breast cancer but also, specify molecular events that could be involved in radiation-induced breast cancer.

Suman, Shubhankar [Department of Biochemistry and Molecular and Cellular Biology, Georgetown University, Washington, DC (United States)] [Department of Biochemistry and Molecular and Cellular Biology, Georgetown University, Washington, DC (United States); Johnson, Michael D. [Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC (United States)] [Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC (United States); Fornace, Albert J. [Department of Biochemistry and Molecular and Cellular Biology, Georgetown University, Washington, DC (United States) [Department of Biochemistry and Molecular and Cellular Biology, Georgetown University, Washington, DC (United States); Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC (United States); Datta, Kamal, E-mail: kd257@georgetown.edu [Department of Biochemistry and Molecular and Cellular Biology, Georgetown University, Washington, DC (United States)] [Department of Biochemistry and Molecular and Cellular Biology, Georgetown University, Washington, DC (United States)

2012-10-01

354

A search for long-term periodicities in large earthquakes of southern and coastal central California  

NASA Technical Reports Server (NTRS)

It has been occasionally suggested that large earthquakes may follow the 8.85-year and 18.6-year lunar-solar tidal cycles and possibly the approximately 11-year solar activity cycle. From a new study of earthquakes with magnitudes greater than 5.5 in southern and coastal central California during the years 1855-1983, it is concluded that, at least in this selected area of the world, no statistically significant long-term periodicities in earthquake frequency occur. The sample size used is about twice that used in comparable earlier studies of this region, which concentrated on large earthquakes.

Stothers, Richard B.

1990-01-01

355

Distinct mechanism for long-term contrast adaptation  

PubMed Central

To optimize perception, neurons in the visual system adapt to the current environment. What determines the durability of this plasticity? Longer exposures to an environment produce longer-lasting effects, which could be due to either (i) a single mechanism controlling adaptation that gains strength over time, or (ii) long-term mechanisms that become active after long-term exposure. Using recently developed technology, we tested adaptation durations an order of magnitude greater that those tested previously, and used a “deadaptation” procedure to reveal effects of a unique long-term mechanism in the longest adaptation periods. After 4 h of contrast adaptation, human observers were exposed to natural images for 15 min, which completely cancelled perceptual aftereffects of adaptation. Strikingly, during continued testing this deadaptation faded, and the original adaptation effects reappeared. This pattern strongly suggests that adaptation was maintained in a distinct long-term mechanism, whereas deadaptation affected a short-term mechanism. PMID:22454502

Bao, Min; Engel, Stephen A.

2012-01-01

356

Short-term and Long-term Variations of Dose Rate measured by MSL/RAD  

NASA Astrophysics Data System (ADS)

The Radiation Assessment Detector (RAD), onboard Mars Science Laboratory’s (MSL) rover Curiosity, measures the spectra of both energetic charged and neutral particles along with radiation dose rate at the surface of Mars. Several effects have been observed for the first time to influence the Galactic Cosmic Ray (GCR)-driven particle radiation on the surface: [a] short-term diurnal variations of the Martian atmospheric pressure caused by daily thermal tides [Rafkin 2014]; [b] long-term seasonal pressure changes in the Martian atmosphere; and [c] the modulation of the primary GCR fluxes by the heliospheric magnetic field, which correlates with long-term solar activities and heliospheric rotation. These concurrent factors affect the dose rate variations measured by RAD on the Martian surface. RAD also recorded the dose rate during the 253-day cruise phase of MSL from the Earth to Mars. The variations of the GCR-induced dose rates during quiet time period without the direct detection of Solar Particle Events (SPE) were solely driven by the changes of heliospheric conditions (i.e. [c]). The RAD cruise and surface dose measurements, along with the surface pressure data and the solar modulation factor, are analysed in order to understand how the long-term influences ([b] and [c]) individually correlate with the measured dose rates.

Guo, Jingnan; Zeitlin, Cary; Rafkin, Scot; Boettcher, Stephan; Reitz, Guenther; Koehler, Jan; Ehresmann, Bent; Martin, Cesar; Burmeister, Soenke; Posner, Arik; Wimmer-Schweingruber, Robert; Hassler, Donald M.; Brinza, David; Boehm, Henning Eckart; Lohf, Henning; Appel, Jan

357

The long-term behavior of the main peak of the dayside ionosphere of venus during solar cycle 21 and its implications on the effect of the solar cycle upon the electron temperature in the main peak region  

Microsoft Academic Search

One hundred four measurements of the peak electron density in the dayside ionosphere of Venus (solar zenith angle (SZA) <80°), along with 11 Venera 9-10 measurements, were analyzed in order to establish the response of the dayside peak to the varying solar EUV flux over the maximum to minimum phase of solar cycle 21 (December 1979 to December 1986). The

Arvydas J. Kliore; Luke F. Mullen

1989-01-01

358

A review of observational evidence for short and long term ultraviolet flux variability of the Sun  

NASA Technical Reports Server (NTRS)

Observation of the Sun in the 160 to 400 nm wavelength region reveals no significant broadband variation with solar flares, variability associated with the rotation of active regions, and a possible long term change which may be related to the 11 year sunspot cycle or longer. A continuing ultraviolet solar flux variability below 200 nm was observed from 1969 through the present from satellites, which is modulated at solar rotation rates. Recent observations from Nimbus-7 show the solar flux is varying by significant amounts also in the regions from 200 nm up to the Calcium 2 H-line at 396.8 nm. Typically the flux may vary over a solar rotation from about 10 percent at 160 nm to slightly less than 1 percent at the Ca2 K-line. Results of an evaluation of observations from rockets, satellites, and the ground measurements are discussed.

Heath, D. F.

1980-01-01

359

Common Calibration Source for Monitoring Long-term Ozone Trends  

NASA Technical Reports Server (NTRS)

Accurate long-term satellite measurements are crucial for monitoring the recovery of the ozone layer. The slow pace of the recovery and limited lifetimes of satellite monitoring instruments demands that datasets from multiple observation systems be combined to provide the long-term accuracy needed. A fundamental component of accurately monitoring long-term trends is the calibration of these various instruments. NASA s Radiometric Calibration and Development Facility at the Goddard Space Flight Center has provided resources to minimize calibration biases between multiple instruments through the use of a common calibration source and standardized procedures traceable to national standards. The Facility s 50 cm barium sulfate integrating sphere has been used as a common calibration source for both US and international satellite instruments, including the Total Ozone Mapping Spectrometer (TOMS), Solar Backscatter Ultraviolet 2 (SBUV/2) instruments, Shuttle SBUV (SSBUV), Ozone Mapping Instrument (OMI), Global Ozone Monitoring Experiment (GOME) (ESA), Scanning Imaging SpectroMeter for Atmospheric ChartographY (SCIAMACHY) (ESA), and others. We will discuss the advantages of using a common calibration source and its effects on long-term ozone data sets. In addition, sphere calibration results from various instruments will be presented to demonstrate the accuracy of the long-term characterization of the source itself.

Kowalewski, Matthew

2004-01-01

360

Long-term corrosion testing pan.  

SciTech Connect

This document describes the testing and facility requirements to support the Yucca Mountain Project long-term corrosion testing needs. The purpose of this document is to describe a corrosion testing program that will (a) reduce model uncertainty and variability, (b) reduce the reliance upon overly conservative assumptions, and (c) improve model defensibility. Test matrices were developed for 17 topical areas (tasks): each matrix corresponds to a specific test activity that is a subset of the total work performed in a task. A future document will identify which of these activities are considered to be performance confirmation activities. Detailed matrices are provided for FY08, FY09 and FY10 and rough order estimates are provided for FY11-17. Criteria for the selection of appropriate test facilities were developed through a meeting of Lead Lab and DOE personnel on October 16-17, 2007. These criteria were applied to the testing activities and recommendations were made for the facility types appropriate to carry out each activity. The facility requirements for each activity were assessed and activities were identified that can not be performed with currently available facilities. Based on this assessment, a total of approximately 10,000 square feet of facility space is recommended to meet all future testing needs, given that all testing is consolidated to a single location. This report is a revision to SAND2007-7027 to address DOE comments and add a series of tests to address NWTRB recommendations.

Wall, Frederick Douglas; Brown, Neil R. (Los Alamos National Laboratory, Los Alamos, NM)

2008-08-01

361

Long-term corrosion testing plan.  

SciTech Connect

This document describes the testing and facility requirements to support the Yucca Mountain Project long-term corrosion testing program. The purpose of this document is to describe a corrosion testing program that will (a) reduce model uncertainty and variability, (b) reduce the reliance upon overly conservative assumptions, and (c) improve model defensibility. Test matrices were developed for 17 topical areas (tasks): each matrix corresponds to a specific test activity that is a subset of the total work performed in a task. A future document will identify which of these activities are considered to be performance confirmation activities. Detailed matrices are provided for FY08, FY09 and FY10 and rough order estimates are provided for FY11-17. Criteria for the selection of appropriate test facilities were developed through a meeting of Lead Lab and DOE personnel on October 16-17, 2007. These criteria were applied to the testing activities and recommendations were made for the facility types appropriate to carry out each activity. The facility requirements for each activity were assessed and activities were identified that can not be performed with currently available facilities. Based on this assessment, a total of approximately 10,000 square feet of facility space is recommended to accommodate all future testing, given that all testing is consolidated to a single location. This report is a revision to SAND2008-4922 to address DOE comments.

Wall, Frederick Douglas; Brown, Neil R. (Los Alamos National Laboratory, Los Alamos, NM)

2009-02-01

362

A new method to estimate annual solar wind parameters and contributions of different solar wind structures to geomagnetic activity  

E-print Network

In this paper, we study two sets of local geomagnetic indices from 26 stations using the principal component (PC) and the independent component (IC) analysis methods. We demonstrate that the annually averaged indices can be accurately represented as linear combinations of two first components with weights systematically depending on latitude. We show that the annual contributions of coronal mass ejections (CMEs) and high speed streams (HSSs) to geomagnetic activity are highly correlated with the first and second IC. The first and second ICs are also found to be very highly correlated with the strength of the interplanetary magnetic field (IMF) and the solar wind speed, respectively, because solar wind speed is the most important parameter driving geomagnetic activity during HSSs while IMF strength dominates during CMEs. These results help in better understanding the long-term driving of geomagnetic activity and in gaining information about the long-term evolution of solar wind parameters and the different sol...

Holappa, Lauri; Asikainen, Timo

2015-01-01

363

Referral from primary care to a physical activity programme: establishing long-term adherence? A randomized controlled trial. Rationale and study design  

Microsoft Academic Search

BACKGROUND: Declining physical activity is associated with a rising burden of global disease. There is little evidence about effective ways to increase adherence to physical activity. Therefore, interventions are needed that produce sustained increases in adherence to physical activity and are cost-effective. The purpose is to assess the effectiveness of a primary care physical activity intervention in increasing adherence to

Maria Giné-Garriga; Carme Martin; Carlos Martín; Anna Puig-Ribera; Juan José Antón; Agustí Guiu; Ana Cascos; Rafel Ramos

2009-01-01

364

Virtual Models of Long-Term Care  

ERIC Educational Resources Information Center

Nursing homes, assisted living facilities and home-care organizations, use web sites to describe their services to potential consumers. This virtual ethnographic study developed models representing how potential consumers may understand this information using data from web sites of 69 long-term-care providers. The content of long-term-care web…

Phenice, Lillian A.; Griffore, Robert J.

2012-01-01

365

Long Term TOA - M Data and Information  

Atmospheric Science Data Center

A Long-Term TOA and Constrained Surface Radiation Budget Project ... (TOA) and surface is a fundamental quantity governing climate variability and, for that reason, NASA has been making concerted ... utilizes knowledge gained in the last 10 years through CERES data analyses and apply the knowledge to existing data to develop long-term ...

2014-08-06

366

Long-Term Care Ombudsman Program  

MedlinePLUS

Long-Term Care Ombudsman Program (OAA, Title VII, Chapter 2, Sections 711/712) The Purpose of the Program and How it ... Services Provided to Persons Living in Long-Term Care Facilities Program data for FY 2013 indicate that ...

367

Influence of solar activity on climate change  

NASA Astrophysics Data System (ADS)

The questions of primary importance for understanding the nature of climate changes in the XX century and main physical processes responsible for these changes are discussed. A physical model of the influence of solar activity on climate characteristics is presented. A key concept of this model is the influence of heliogeophysical disturbances on the Earth's climate system parameters controlling the long-wave radiation flux going out into space in high-latitude regions. A change in the Earth's radiation balance of high-latitude regions induces restructuring of the tropospheric thermobaric field, changes in the meridional temperature gradient responsible for meridional heat transfer. This causes changes in the heat content of the Earth's climate system and global climate. We present and discuss results of analysis of regularities and peculiarities of tropospheric and sea surface temperature (SST) responses both to separate heliogeophysical disturbances and to long-term changes of solar and geomagnetic activity. It is established that the climatic response in the tropospheric and sea surface temperature to the effect of solar and geomagnetic activity is characterised by a significant space-time irregularity and is local. A distinguishing feature of these distributions is the presence of regions of both positive and negative correlations. The exception is the epoch (1910-1940) when the SST response to geomagnetic activity was positive in virtually all regions, i. e. was global. This epoch coincides with the longest period of increase in geomagnetic activity during the period considered at the end of which annual averages of geomagnetic activity exceeded maximum values at the beginning of the epoch. Key words: climate, ocean, troposphere, solar activity.

Kirichenko, Kirill; Kovalenko, Vladimir

368

Long-term potentiation: peeling the onion  

PubMed Central

Since the discovery of long-term potentiation (LTP), thousands of papers have been published on this phenomenon. With this massive amount of information, it is often difficult, especially for someone not directly involved in the field, not to be overwhelmed. The goal of this review is to peel away as many layers as possible, and probe the core properties of LTP. We would argue that the many dozens of proteins that have been implicated in the phenomenon are not essential, but rather modulate, often in indirect ways, the threshold and/or magnitude of LTP. What is required is NMDA receptor activation followed by CaMKII activation. The consequence of CaMKII activation is the rapid recruitment of AMPA receptors to the synapse. This recruitment is independent of AMPA receptor subunit type, but absolutely requires an adequate pool of surface receptors. An important unresolved issue is how exactly CaMKII activation leads to modifications in the PSD to allow rapid enrichment. PMID:23439383

Nicoll, Roger A.; Roche, Katherine W.

2013-01-01

369

Leptin affects adenylate cyclase activity in H9c2 cardiac cell line: effects of short- and long-term exposure  

Microsoft Academic Search

Leptin has been hypothesized to be a pathophysiologic link between obesity and cardiovascular diseases. Because the adenylate cyclase (AC) system is a main effector of ?-adrenergic receptors and leptin has been shown to modulate AC activity in other cell lines, a leptin impact on cardiac AC activity was hypothesized. Therefore, acute and chronic effects of leptin on a rat cardiac

Gennaro Illiano; Silvio Naviglio; Mario Pagano; Annamaria Spina; Emilio Chiosi; Michelangela Barbieri; Giuseppe Paolisso

2002-01-01

370

Changes in the biological activity of chestnut soils upon the long-term application of fertilizers in a rotation with oil-bearing crops  

NASA Astrophysics Data System (ADS)

Experimental studies showed that irrigated chestnut soils on the piedmont of the Zailiiskiy Alatau Range are characterized by the moderate activity of the hydrolytic and redox enzymes. The use of these soils in the crop rotation system increases the hydrolytic activity of the enzymes (invertase, urease, and ATP synthase) by 30% in comparison with the monoculture; at the same time, it does not have a significant impact on the changes in the biological activity of the redox enzymes (catalase and dehydrogenase). The hydrolytic activity of the soils is activated to a greater extent in the crop rotation and in the monoculture against the background application of organic fertilizers. In this case, the recommended rates of mineral fertilizers do not inhibit the activity of the hydrolytic and redox enzymes. An increase in the hydrolytic activity of the enzymes directly affects the yield of oilseed flax. Therefore, indices of the hydrolytic activity of soils can be used as a test for the diagnostics of the efficiency of fertilizers both in crop rotation and monoculture systems.

Eleshev, R. E.; Bakenova, Z. B.

2012-11-01

371

Long-term care in North Carolina.  

PubMed

Much of long-term care is not considered health care, as it is custodial, social, and supportive. But excellent long-term care is also preventive, timely, and accessible, and it provides space for long-term care recipients to find joy and meaning in their lives. This issue of the NCMJ provides abroad overview of long-term care, practical information about programs in our state, and tips for how to make use of these programs. Commentaries and sidebars in this issue also highlight new ideas, innovation, and transformation. This issue brief sets the stage by describing major events that have shaped the current framework of long-term care services and supports. It also discusses current trends that are influencing long-term care, including the emphasis on quality improvement methods, culture change, health care reform, the influence of geriatrics in primary care, and the desire for home-based care. Although we are not yet where we want to be in North Carolina, we are moving toward a long-term care system that will serve all North Carolinians well. PMID:25237870

White, Heidi K

2014-01-01

372

'Perforated patch recording' allows long-term monitoring of metabolite-induced electrical activity and voltage-dependent Ca2+ currents in pancreatic islet B cells.  

PubMed

We describe the application of 'perforated patch recording' using the pore-forming antibiotic nystatin, to monitor the electrical activity and underlying ionic currents of rat and human pancreatic islet B cells. We demonstrate that glucose-induced electrical activity is seen even in single B cells during current-clamp recordings lasting hours 'L-type' Ca2+-channel currents can also be monitored over this period of time. This technique may prove useful in examining hormone and neurotransmitter modulation of electrical activity in B cells, while minimizing the effects of cytoplasmic 'wash-out'. PMID:2473925

Falke, L C; Gillis, K D; Pressel, D M; Misler, S

1989-07-17

373

Long-term decrease in Na(+),K(+)-ATPase activity after pilocarpine-induced status epilepticus is associated with nitration of its alpha subunit.  

PubMed

Temporal lobe epilepsy (TLE) is the most common type of epilepsy with about one third of TLE patients being refractory to antiepileptic drugs. Knowledge about the mechanisms underlying seizure activity is fundamental to the discovery of new drug targets. Brain Na(+),K(+)-ATPase activity contributes to the maintenance of the electrochemical gradients underlying neuronal resting and action potentials as well as the uptake and release of neurotransmitters. In the present study we tested the hypothesis that decreased Na(+),K(+)-ATPase activity is associated with changes in the alpha subunit phosphorylation and/or redox state. Activity of Na(+),K(+)-ATPase decreased in the hippocampus of C57BL/6 mice 60 days after pilocarpine-induced status epilepticus (SE). In addition, the Michaelis-Menten constant for ATP of ?2/3 isoforms increased at the same time point. Nitration of the ? subunit may underlie decreased Na(+),K(+)-ATPase activity, however no changes in expression or phosphorylation state at Ser(943) were found. Further studies are necessary define the potential of nitrated Na(+),K(+)-ATPase as a new therapeutic target for seizure disorders. PMID:25311690

Funck, Vinícius Rafael; Ribeiro, Leandro Rodrigo; Pereira, Letícia Meier; Oliveira, Clarissa Vasconcelos de; Grigoletto, Jéssica; Fighera, Michele Rechia; Royes, Luiz Fernando Freire; Furian, Ana Flávia; Oliveira, Mauro Schneider

2014-12-01

374

Effects of Long-Term Nitrogen Addition on Microbial Enzyme  

E-print Network

Effects of Long-Term Nitrogen Addition on Microbial Enzyme Activity in Eight Forested and Grassland of microbially produced extracellu- lar enzymes involved in decomposition. Specifi- cally, it is hypothesized that adding N to N-limited ecosystems increases activity of cellulose degrading enzymes and decreases

Minnesota, University of

375

Variation in metabolic enzymatic activity in white muscle and liver of blue tilapia, Oreochromis aureus, in response to long-term thermal acclimatization  

NASA Astrophysics Data System (ADS)

The effects of rearing temperature on white muscle and hepatic phosphofructokinase (PFK), pyruvate kinase (PK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were examined in fingerlings of blue tilapia, Oreochromis aureus. The experiment was conducted for 14 weeks at temperatures of 18, 22, 26, 30, and 34°C. The activity of the glycolytic enzymes PFK, PK, and LDH in white muscle increased significantly with increase in water temperature. A reverse trend was observed for these enzymes in the liver, except for LDH, which behaved in the same manner as in white muscle. Cytosolic AST and ALT activity increased in both white muscle and liver in response to warm thermal acclimatization, while a reduction in mitochondrial AST and ALT activity was noticed at high temperatures in comparison with those at a lower temperature.

Younis, Elsayed M.

2015-01-01

376

Lessons from Long-term Studies  

E-print Network

Lessons from Long-term Studies Gordon Reeves U.S. Forest Service PNW Research Station Corvallis #12 for a watershed and reaches to produce fish depends on inherent features #12;#12;Elk River Chinook Salmon Numbers

377

State Medicaid Programs (Long-Term Care)  

MedlinePLUS

... your family by thinking ahead and making your decisions known. Costs & How to Pay Long-term care is expensive, but there are several ways ... is a joint federal and state government program that helps people with low income and ...

378

Long Term Effects of Food Poisoning  

MedlinePLUS

... develop chronic arthritis. Brain and nerve damage A Listeria infection can lead to meningitis, an inflammation of ... brain. If a newborn infant is infected with Listeria , long-term consequences may include mental retardation, seizures, ...

379

Long-Term Fungal Inhibitory Activity of Water-Soluble Extracts of Phaseolus vulgaris cv. Pinto and Sourdough Lactic Acid Bacteria during Bread Storage  

Microsoft Academic Search

The antifungal activity of proteinaceous compounds from different food matrices was investigated. In initial experiments, water-soluble extracts of wheat sourdoughs, cheeses, and vegetables were screened by agar diffusion assays with Penicillium roqueforti DPPMAF1 as the indicator fungus. Water-soluble extracts of sourdough fermented with Lactobacillus brevis AM7 and Phaseolus vulgaris cv. Pinto were selected for further study. The crude water-soluble extracts

Rossana Coda; Carlo G. Rizzello; Franco Nigro; Maria De Angelis; Philip Arnault; Marco Gobbetti

2008-01-01

380

Long-term effects of radioprotector WR-2721 on locomotor activity and body weight of mice following exposure to ionizing radiation. Scientific report  

Microsoft Academic Search

The effects of 13-Gy gamma radiation alone and in combination with 200 mg\\/kg of the radioprotector S-2-(3-aminopropylamino ethylphosphorothioic acid (WR-2721) on locomotor activity and body weight were examined in CD2F1 mice over a 10-month period. The results confirmed that WR-2721 is an excellent radioprotector against lethality. All mice receiving 13 Gy without WR-2721 died in 5-7 days. For mice that

M. R. Landauer; H. D. Davis; J. A. Dominitz; J. F. Weiss

1988-01-01

381

Long-term effects of combined hormone replacement therapy on markers of endothelial function and inflammatory activity in healthy postmenopausal women  

Microsoft Academic Search

Objective: To study the effects of combined hormone replacement therapy on markers of endothelial function and inflammatory activity.Design: Prospective, randomized, controlled study.Setting: Academic hospital.Patient(s): Healthy postmenopausal women with an intact uterus.Intervention(s): For the first 12 months, the hormone replacement therapy group (n = 14) received oral E2, 1 mg daily, sequentially combined with 5 or 10 mg of dydrogesterone. Thereafter,

W. Marchien van Baal; Peter Kenemans; Jef J Emeis; Casper G Schalkwijk; Velja Mijatovic; Marius J van der Mooren; Ulrich M Vischer; Coen D. A Stehouwer

1999-01-01

382