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1

Long-term persistence of solar activity  

NASA Astrophysics Data System (ADS)

The solar irradiance has been found to change by 0.1% over the recent solar cycle. A change of irradiance of about 0.5% is required to effect the Earth's climate. How frequently can a variation of this size be expected? We examine the question of the persistence of non-periodic variations in solar activity. The Huerst exponent, which characterizes the persistence of a time series (Mandelbrot and Wallis, 1969), is evaluated for the series of C-14 data for the time interval from about 6000 BC to 1950 AD (Stuiver and Pearson, 1986). We find a constant Huerst exponent, suggesting that solar activity in the frequency range of from 100 to 3000 years includes an important continuum component in addition to the well-known periodic variations. The value we calculate, H approximately equal to 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 (Ruzmaikin et al., 1992), and that is is the same type of process over a wide range of time interval lengths. We conclude that the time period over which an irradiance change of 0.5% can be expected to occur is significantly shorter than that which would be expected for variations produced by a white-noise process.

Ruzmaikin, Alexander; Feynman, Joan; Robinson, Paul

1994-06-01

2

Long-term persistence of solar activity  

NASA Astrophysics Data System (ADS)

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

1994-02-01

3

Relationship of Long-Term Solar Activity and Geomagnetic Activity  

NASA Astrophysics Data System (ADS)

Solar acitivity influences geomagnetic activity both in short-term and long-term. The short term effect due to daily solar activity, while long term effect due to about 11-year and 22-year cycles of solar activity. Results of Weighted Wavelet Z-Transform (WWZ) analysis on both of Kp index and sunspot number data yield dominant periods of approx. 11-years and approx. 24-years. But there is an other four-year period of the Kp index. Further studies are required to show whether it is affected by solar activity or not. The strongest effect of solar activity on geomagnetic activity comes from 11-year and 22-year sunspot cycles. This can be seen from correlation coefficient of Kp index and sunspot number as large as 0.8 and 0.7 for average move 11-year and 22-years, respectively. The other result that geomagnetic activity follow solar activity with a time lag of two to three years.

Musafar, K. La Ode Muh; Sinambela, Wilson; Cahyono, Waluyo

2000-04-01

4

Long-term correlation between solar and geomagnetic activity  

NASA Astrophysics Data System (ADS)

A long-term correlation study between solar and geomagnetic activity is reported in this work using annual averages of the aa index and of the sunspot number Rz in the period of 1868-2000. Dst and AE geomagnetic indices and solar wind speed data are used for more recent periods. It is shown that the geomagnetic and solar activity correlation has decreased since the end of the 19th century, and the lag between them has increased. The variations of Rz and aa were in phase in the early period (solar cycles 11-14, around 1868-1910), and became out of phase in later periods (with a lag of 2 years in solar cycle 22, with aa maximum after Rz). Nevertheless, this trend is not monotonic and superposed fluctuations are seen, which does not permit determine if this correlation decrease is part or not of a long period solar activity cycle. The probable cause of the correlation decrease seems to be related to the aa index dual peak structure. The second aa peak seems to have increased relative to the first one. This second peak is more related to the high-speed streams originated from co-rotating structures whereas the first one is related to sunspot (coronal mass ejections) activity. In recent periods, since 1964, it has been observed that aa annual values have higher correlation with the fraction of days per year with daily solar wind speed peaks larger than 500km/s(Fpk) than with Rz. The aa index also shows larger correlation with AE index than with Dst. Thus, it seems that average aa is strongly influenced by AE activity, which is influenced mainly by high speed streams from coronal holes. One can conclude that the decrease in correlation between aa and Rz occurs because the second aa peak has becoming stronger relative to the first one. The cause seems to be that open solar magnetic field structures have increased their activity relative to the closed (sunspot-related) solar magnetic field structures. This implies that the global solar magnetic field could have experienced a differential (between closed and open structures) large-scale variation in the last 130 years.

Echer, E.; Gonzalez, W. D.; Gonzalez, A. L. C.; Prestes, A.; Vieira, L. E. A.; dal Lago, A.; Guarnieri, F. L.; Schuch, N. J.

2004-08-01

5

Long-term solar activity influences on South American rivers  

NASA Astrophysics Data System (ADS)

River streamflows are excellent climatic indicators since they integrate precipitation over large areas. Here we follow up on our previous study of the influence of solar activity on the flow of the Paraná River, in South America. We find that the unusual minimum of solar activity in recent years have a correlation on very low levels in the Paraná's flow, and we report historical evidence of low water levels during the Little Ice Age. We also study data for the streamflow of three other rivers (Colorado, San Juan and Atuel), and snow levels in the Andes. We obtained that, after eliminating the secular trends and smoothing out the solar cycle, there is a strong positive correlation between the residuals of both the Sunspot Number and the streamflows, as we obtained for the Paraná. Both results put together imply that higher solar activity corresponds to larger precipitation, both in summer and in wintertime, not only in the large basin of the Paraná, but also in the Andean region north of the limit with Patagonia.

Mauas, Pablo J. D.; Buccino, Andrea P.; Flamenco, Eduardo

2011-02-01

6

Long-term persistence of solar activity. [Abstract only  

NASA Technical Reports Server (NTRS)

The solar irradiance has been found to change by 0.1% over the recent solar cycle. A change of irradiance of about 0.5% is required to effect the Earth's climate. How frequently can a variation of this size be expected? We examine the question of the persistence of non-periodic variations in solar activity. The Huerst exponent, which characterizes the persistence of a time series (Mandelbrot and Wallis, 1969), is evaluated for the series of C-14 data for the time interval from about 6000 BC to 1950 AD (Stuiver and Pearson, 1986). We find a constant Huerst exponent, suggesting that solar activity in the frequency range of from 100 to 3000 years includes an important continuum component in addition to the well-known periodic variations. The value we calculate, H approximately equal to 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 (Ruzmaikin et al., 1992), and that is is the same type of process over a wide range of time interval lengths. We conclude that the time period over which an irradiance change of 0.5% can be expected to occur is significantly shorter than that which would be expected for variations produced by a white-noise process.

Ruzmaikin, Alexander; Feynman, Joan; Robinson, Paul

1994-01-01

7

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.

8

Long-term variations in the correlation between solar activity and climate  

NASA Astrophysics Data System (ADS)

The problem of solar activity influences on climate is controversial - some authors have found positive correlations between solar activity and different meteorological parameters, others negative correlations, still others no correlations at all. On the basis of all available global and zonal averages of surface air temperature, as well as measurements in individual stations with long data records we show that the sign of the correlation is the same in different locations, and changes regularly from one secular solar cycle (SSC) to the other, with the sign depending on the long-term solar activity asymmetry.

Georgieva, K.; Kirov, B.; Bianchi, C.

9

Long-Term Global Solar Activity Observed by the Nobeyama Radioheliograph  

NASA Astrophysics Data System (ADS)

The Nobeyama Radioheliograph has been observing the Sun at a frequency of 17 GHz regularly since 1992, providing synthesized full-disk images. This long period of continuous and consistent operation, providing well-calibrated data of a uniform standard, makes possible long-term studies of solar activity, from full-disk down to the angular resolution of the instrument. By using about 7200 daily, full-disk images, it has been possible to generate a radio version of the butterfly diagram, which differs significantly from the sunspot butterfly diagram. The polar regions are bright at 17 GHz, with their brightness well-correlated with the polar magnetic field strengths. Both are anti-correlated with activity at low latitudes, such as active regions and solar flares. The 17 GHz butterfly diagram shows both high and low-latitude activity. The brightness of both these facets of solar activity shows a significant decline over the 20+ years observations that have been made. In the northern hemisphere, the radio brightnesses at low and high latitudes are strongly anti-correlated. However, this anti-correlation is weak in the southern hemisphere. We find a weakening of the synchronization of activity between the northern and southern hemispheres, and also between high and low latitude activity in the southern hemisphere. Possible causes of polar brightening and the meaning with respect to the general scenario of solar activity are discussed.

Shibasaki, Kiyoto

2013-12-01

10

Solar causes of the long-term increase in geomagnetic activity  

NASA Astrophysics Data System (ADS)

We analyze the causes of the century-long increase in geomagnetic activity, quantified by annual means of the aa index, using observations of interplanetary space, galactic cosmic rays, the ionosphere, and the auroral electrojet, made during the last three solar cycles. The effects of changes in ionospheric conductivity, the Earth's dipole tilt, and magnetic moment are shown to be small; only changes in near-Earth interplanetary space make a significant contribution to the long-term increase in activity. We study the effects of the interplanetary medium by applying dimensional analysis to generate the optimum solar wind-magnetosphere energy coupling function, having an unprecedentedly high correlation coefficient of 0.97. Analysis of the terms of the coupling function shows that the largest contributions to the drift in activity over solar cycles 20-22 originate from rises in the average interplanetary magnetic field (IMF) strength, solar wind concentration, and speed; average IMF orientation has grown somewhat less propitious for causing geomagnetic activity. The combination of these factors explains almost all of the 39% rise in aa observed over the last three solar cycles. Whereas the IMF strength varies approximately in phase with sunspot numbers, neither its orientation nor the solar wind density shows any coherent solar cycle variation. The solar wind speed peaks strongly in the declining phase of even-numbered cycles and can be identified as the chief cause of the phase shift between the sunspot numbers and the aa index. The rise in the IMF magnitude, the largest single contributor to the drift in geomagnetic activity, is shown to be caused by a rise in the solar coronal magnetic field, consistent with a rise in the coronal source field, modeled from photospheric observations, and an observed decay in cosmic ray fluxes.

Stamper, R.; Lockwood, M.; Wild, M. N.; Clark, T. D. G.

11

Long-term cosmic ray intensity variation and part of global climate change, controlled by solar activity through cosmic rays  

NASA Astrophysics Data System (ADS)

In this paper, we investigate properties long-term variations in galactic cosmic ray intensity as an important possible link in the connection between solar activity variation and global climate change. There are two main aims of the paper: (1) to estimate how solar activity influences on galactic CR long-term variations, what are the relative role in this influence of convection-diffusion modulation and drift modulation and (2) to estimate the expected part of global climate change which may be caused by the influence of solar activity cycle on climate through 11- and 22-year cosmic ray variations.

Dorman, L. I.

12

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

13

Long-term oscillations in solar active regions based on magnetic fields and radio emission  

NASA Astrophysics Data System (ADS)

A comparative analysis of sunspot oscillations and related radio sources in the active regions AR 8949, AR 8951, and AR 8953 is carried out using SOHO MDI data and simultaneous observations with the Nobeyama Radioheliograph, with a one-minute time resolution on scales of tens to hundreds of minutes. The radio sources in the selected active regions are ˜40 000-60 000 km away from the corresponding spots, with the periods of long-term oscillations of the radio sources being ˜12% longer.

Nagovitsyn, Yu. A.; Nagovitsyna, E. Yu.; Abramov-Maximov, V. E.

2013-08-01

14

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

15

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

Microsoft Academic Search

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 give opposite results. The better

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

1977-01-01

16

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

17

What Is Missing from Our Understanding of Long-Term Solar and Heliospheric Activity?  

NASA Astrophysics Data System (ADS)

The heliospheric magnetic field is associated with changes in space weather, cosmic-ray flux, and likely climate. This field is determined by the largest scale patterns of magnetism at the solar surface, dominated by the lower latitude active regions during cycle maximum and by the circumpolar fields during cycle minimum. Whereas the magnetic field in the activity belt is readily studied, the high-latitude field is much less accessible, and its study requires a combination of modeling and observation. Current models hold that the high-latitude magnetic field on the Sun is determined solely by the accumulation of field transported poleward from lower latitude active regions. We test this hypothesis by simulating the evolution of the magnetic field at the solar surface and in the heliosphere during the last 340 yr using a state-of-the-art model that incorporates all processes that are known to contribute significantly to the evolution of the large-scale patterns in the solar field. We find that if only the emergence frequency of magnetic bipoles is varied in accordance with observed sunspot records, the polar-cap field reservoir does not match measurements during past years. Based on comparisons of our simulations with observed polar fluxes over the last few decades and with the proxy for the heliospheric flux formed by 340 yr of 10Be ice-core data, we suggest that the high-latitude field may be subject to decay on a timescale of 5-10 yr. We discuss the consequences of this finding for our understanding of the Sun-Earth connection and explore inferences for the coupling of the Sun's internal magnetic field to the heliospheric field.

Schrijver, Carolus J.; De Rosa, Marc L.; Title, Alan M.

2002-10-01

18

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

Microsoft Academic Search

We have developed a method to map large-scale horizontal velocity fields in the solar photosphere. The method was developed, tuned, and calibrated using synthetic data. Now, we apply the method to the series of Michelson Doppler Imager (MDI) Dopplergrams covering almost one solar cycle to generate the information about the long-term behaviour of surface flows. Our method clearly reproduces the

Michal Svanda; Mirek Klvana; Michal Sobotka; Vaclav Bumba

2008-01-01

19

About the nature of long-term microflare energy release in solar active regions  

NASA Astrophysics Data System (ADS)

In this paper we compare the long-term impulsive microflares (microbursts (MB) in the range 1000 MHz) using RATAN-600 observations and impulsive noise storm (NS) emission on frequencies 233 and 164 MHz using Nancay radioheliograph data. It is shown that these processes result from destruction of current sheets at the top of a coronal loop as a result of the development of plasma instability sequences. The coincidence in time between the generation of microbursts and coronal mass ejections is of special interest. The impulses of NS radio emission at meter waves arise after the appearance of the MB at decimeter waves. The temporal parameters of the processes are determined. It is shown that the MB duration is determined by the spreading time of the magnetic flux in the reconnection region along the current sheet. The flux of energy in the form of fast electrons is equal to 9.2×104ergscm-2s-1.

Bogod, Vladimir M.; Mercier, Claude; Yasnov, Leonid V.

2001-11-01

20

The role of energy exchange between the eddies and the mean flow for the long-term modulation of the solar activity  

NASA Astrophysics Data System (ADS)

The variability of the magnetic features observed in the outer layers of the solar atmosphere is determined by the energetic coupling between the circulation in the convection zone and the solar magnetic field. The 11-year cycle variability is remarkable and was identified few cycles after systematic telescopic observations of sunspots became available. These quasi-periodic oscillations are registered in several parameters such as the total solar irradiance, which is the main external source of energy of the highly coupled Earth's atmospheric/oceanic system. The long-term evolution of the solar activity is also clearly observed in direct and indirect proxies of the solar activity. Periods of low (grand minima) and high (grand maxima) solar activity occurred during the Holocene. However, the precise mechanism that drives the long-term evolution of the solar activity is unknown. Here we show that large storms at the bottom of the convection zone can drive the long-term evolution of the solar activity. We found that the exchange of energy between the mean flow and perturbations of the velocity fields imposed by large cyclonic/anti-cyclonic activity at the bottom of the convection zone is mapped to the outer layers of the solar atmosphere. We anticipate that the relationships found will allow us to model the long-term evolution of the solar cycle activity through the Holocene. We point out that this mechanism requires much less energy them the one based on changes of the meridional circulation. This approach will also help us to constrain the long-term evolution of key solar cycle parameters that are employed to model the long-term evolution of the total and spectral solar irradiance, which are needed to untangle the natural and anthropogenic drivers of the present climate change.

Vieira, L. A.; Dudok de Wit, T.; Da Silva, L. A.

2011-12-01

21

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

22

Prominent short-, mid-, and long-term periodicities in solar and geomagnetic activity: Wavelet analysis  

NASA Astrophysics Data System (ADS)

Study of periodicities in solar and geomagnetic parameters has been useful in relating solar variability to variations in other phenomena in order to search for the solar cause of, and effects in, the variability observed in near earth space environment. Implementing wavelet analysis on daily, monthly and yearly time resolution data of sunspot number and geomagnetic aa-index, we observed periodicities of 27.8-, 157-, 370-days, and 2.2-, 5.5-, 11-, 22.7-, 38.6-years in the sunspot spot number and 13.8-, 26.6-, 185-days, and 5.3-, 11-, 30-, 46-years in the geomagnetic aa-index. We discuss these periodicities, relation between solar and geomagnetic periodicities and their implications for near-earth space environmental effects. Daily, monthly and yearly solar and geomagnetic data analyzed using wavelet analysis. Several periodicities detected in solar and geomagnetic data. Signature of 38.6-year periodicity observed in sunspot data. Six month (semi-annual) cycle prominently seen in aa-index. The ~30-year periodicity observed in aa-index using daily, monthly and yearly data.

Singh, Y. P.; Badruddin

2014-06-01

23

Optimal prediction of the peak of the next 11-year activity cycle and of the peaks of several succeeding cycles on the basis of long-term variations in the solar radius or solar constant  

Microsoft Academic Search

We propose a new technique for the optimal prediction of the peak of the next 11-year activity cycle prior to the cycle beginning\\u000a and of the peaks of several succeeding cycles on the basis of long-term variations in the solar radius or solar constant.\\u000a The method is based on the already established fact that the long-term cyclic variations of the

Kh. I. Abdusamatov

2007-01-01

24

The Long-Term Hemispheric Sunspot Activity  

NASA Astrophysics Data System (ADS)

Sunspot activity is usually represented by either sunspot numbers (SN) or sunspot areas (SA). The smoothed monthly mean SA and SN in the northern and southern hemispheres from 1945 January to 2008 March are used to investigate the characteristics of long-term hemispheric sunspot activity. Although sunspot activity (SA and SN) is found to begin one month earlier in the northern hemisphere than in the southern hemisphere on the average of the considered time interval, the shift is so small that no long-term systematic phase shift is statistically acceptable as a first-order effect, as suggested by White & Trotter. Sunspot activity never peaks at the same time in the two hemispheres. Although the Schwabe cycle appears in hemispheric sunspot activity, its period length slightly varies during the considered time interval and seems to be longer in the southern hemisphere than in the northern hemisphere on the average. Sunspot activity is asymmetrically distributed in the hemispheres, but the largest hemispheric diversity usually does not appear around the maximum time of a cycle. The diversity of SA, respectively, in the northern and southern hemispheres runs on the Sun similarly and synchronously as the diversity of SN does. Sunspot activity is slightly asynchronous in the hemispheres.

Li, K. J.; Gao, P. X.; Zhan, L. S.; Shi, X. J.

2009-01-01

25

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

26

Long term stability and performance of solar system instrumentation  

SciTech Connect

In an attempt to improve the quality and reliability of methods used for long-term performance evaluation of solar systems, detailed information is provided about the long-term (typically over 2 years) performance and stability of a relatively large number of instruments used in the performance monitoring of a well-instrumented solar heating project. The calibration methods are also described. The instruments include resistance temperature detectors, several types of flowmeters, wattmeters, pyranometers, wind anemometers, a humidity meter, a barometer, differential temperature solar system controllers, and an automatic data acquisition system used to scan, convert and store the data. Recommendations for good instrumentation of solar systems are also provided. It was found that the critical instruments for performance evaluation, and most of the instruments overall, have performed very well over the long term, allowing thermal performance evaluation with an accuracy better than 3% with only one calibration per year.

Lior, N.; Brish, R.T.; Koffs, S.; Tedori, L.

1983-11-01

27

Long-term changes in the North-South asymmetry of solar activity: a nonlinear dynamics characterization using visibility graphs  

NASA Astrophysics Data System (ADS)

Solar activity is characterized by complex dynamics superimposed to an almost periodic, about 11 years cycle. One of its main features is the presence of a marked, time-varying hemispheric asymmetry, the deeper reasons of which have not yet been completely uncovered. Traditionally, this asymmetry has been studied by considering amplitude and phase differences. Here, we use visibility graphs, a novel tool of nonlinear time series analysis, to obtain complementary information on hemispheric asymmetries in dynamical properties. Our analysis provides deep insights into the potentials and limitations of this method, revealing a complex interplay between factors relating to statistical and dynamical properties, i.e., effects due to the probability distribution and the regularity of observed fluctuations. We demonstrate that temporal changes in the hemispheric predominance of the graph properties lag those directly associated with the total hemispheric sunspot areas. Our findings open a new dynamical perspective on studying the North-South sunspot asymmetry, which is to be further explored in future work.

Zou, Y.; Donner, R. V.; Marwan, N.; Small, M.; Kurths, J.

2014-04-01

28

Long-term physical-statistical modelling of Southern Oscillation and climatic parameters in view of solar activity influence on greenhouse effect.  

NASA Astrophysics Data System (ADS)

The long-term several decades forecasts of Southern Oscillation ENSO and climatic parameters of some regions of Southern and Central America and Europe are here represented The modelling was performed on the basis of physical-statistical model which is based on a concept of solar activity influence on greenhouse effect through some physical mechanism There are two reasons in support the existence of such mechanism begin enumerate item firstly a presence of rather close correlation between an average meanings intervals of sliding averaging are from several decades up to hundreds years of solar activity and earth surfaces temperatures variations actual and reconstructed item and secondly insufficient change of insolation for an explanation of existing correlation connected with solar activity change end enumerate The simple estimate model has shown a possibility of an explanation of recent warming by the natural reasons without using of anthropogenic factors The constructed model in spite of its simplicity well enough reproduces and explains the basic climatic events of the past millennium global warming at 19 th -20 th and 11 th -13 th centuries small glacial period at 15 th -17 th centuries The integrated energy parameters of ocean - atmosphere system are the arguments of statistical part of the model and on the other hand they are the output of physical part of the model The analysis of the model has shown that it can be successfully adapted to the various large-scale first of all - in

Khorozov, S.; Budovy, V.; Medvedev, V.; Martin, I.; Belogolov, V.

29

Long-term solar activity and its implications to the heliosphere, geomagnetic activity, and the Earth's climate. Preface to the Special Issue on Space Climate  

NASA Astrophysics Data System (ADS)

The Sun's long-term magnetic variability is the primary driver of space climate. This variability is manifested not only in the long-observed and dramatic change of magnetic fields on the solar surface, but also in the changing solar radiative output across all wavelengths. The Sun's magnetic variability also modulates the particulate and magnetic fluxes in the heliosphere, which determine the interplanetary conditions and impose significant electromagnetic forces and effects upon planetary atmospheres. All these effects due to the changing solar magnetic fields are also relevant for planetary climates, including the climate of the Earth. The ultimate cause of solar variability, at time scales much shorter than stellar evolutionary time scales, i.e., at decadal to centennial and, maybe, even millennial or longer scales, has its origin in the solar dynamo mechanism. Therefore, in order to better understand the origin of space climate, one must analyze different proxies of solar magnetic variability and develop models of the solar dynamo mechanism that correctly produce the observed properties of the magnetic fields. This Preface summarizes the most important findings of the papers of this Special Issue, most of which were presented in the Space Climate-4 Symposium organized in 2011 in Goa, India.

Mursula, Kalevi; Manoharan, Periasamy; Nandy, Dibyendu; Tanskanen, Eija; Verronen, Pekka

2013-06-01

30

Long-term integrations of the Solar System  

Microsoft Academic Search

While long-term numerical integrations of the outer Solar System have become routine, the inner planets have received much less attention. The present work uses physical models of increasing complexity, which include General Relativistic and Earth-Moon tidal corrections. Even small modifications in the physical model can lead to changes in orbits over a few million years that are larger than what

F. Varadi

2000-01-01

31

Analysis of Solar Irradiation Anomalies in Long Term Over India  

NASA Astrophysics Data System (ADS)

India has a high potential for solar energy applications due to its geographic position within the Sun Belt and the large number of cloudless days in many regions of the country. However, certain regions of India, particularly those largely populated, can exhibit large aerosol loading in the atmosphere as a consequence of anthropogenic emissions that could have a negative feedback in the solar resource potential. This effect, named as solar dimming, has already been observed in India, and in some other regions in the world, by some authors using ground data from the last two decades. The recent interest in the promotion of solar energy applications in India highlights the need of extending and improving the knowledge of the solar radiation resources in this country, since most of the long term measurements available correspond to global horizontal radiation and most of them are also located big cities or highly populated areas. In addition, accurate knowledge on the aerosol column quantification and on its dynamical behavior with high spatial resolution is particularly important in the case of India, due to their impact on direct normal irradiation. Long term studies of solar irradiation over India can be performed using monthly means of global hemispheric irradiation measurements from the Indian Meteorological Department. Ground data are available from 1964 till today through the World Radiation Data Centre that publish these values in the web. This work shows a long term analysis of solar irradiation in India using anomalies techniques and trends in ten places over India. Most of the places have exhibit a decreasing trend and negative anomalies confirming thus the darkening effect already reported by solar dimming studies. The analysis of anomalies has also found two periods of different behavior. From 1964 till 1988 the anomalies observed were positive and the last 20 years seems to be a period of negative anomalies. This observation is also consequent with solar dimming effect, apparently increased during the last two decades due to the increase of aerosol loading in the atmosphere. These results remark the important of having accurate knowledge of atmospheric aerosol loading and its dynamics over India with high spatial resolution in the framework of solar energy deployment in the country. It is worth to mention that greater anomalies and a noticeable decreasing trend found in Calcutta could be correlated with the highly population rate, and thus the greater the population density of the area the greater the negative anomalies and the decreasing trend of solar irradiation monthly means.

Cony, M.; Polo, J.; Martin, L.; Navarro, A.; Serra, I.

2012-04-01

32

Long-term goals for solar thermal technology  

SciTech Connect

This document describes long-term performance and cost goals for three solar thermal technologies. Pacific Northwest Laboratory (PNL) developed these goals in support of the Draft Five Year Research and Development Plan for the National Solar Thermal Technology Program (DOE 1984b). These technology goals are intended to provide targets that, if met, will lead to the widespread use of solar thermal technologies in the marketplace. Goals were developed for three technologies and two applications: central receiver and dish technologies for utility-generated electricity applications, and central receiver, dish, and trough technologies for industrial process heat applications. These technologies and applications were chosen because they are the primary technologies and applications that have been researched by DOE in the past. System goals were developed through analysis of future price projections for energy sources competing with solar thermal in the middle-to-late 1990's time frame. The system goals selected were levelized energy costs of $0.05/kWh for electricity and $9/MBtu for industrial process heat (1984 $). Component goals established to meet system goals were developed based upon projections of solar thermal component performance and cost which could be achieved in the same time frame.

Williams, T.A.; Dirks, J.A.; Brown, D.R.

1985-05-01

33

Long-term variations in total solar and UV irradiances  

NASA Technical Reports Server (NTRS)

The variations of total solar and UV irradiances during solar cycles 21 and 22 are compared. The total solar irradiance data used were obtained by the SMM/active cavity radiometer irradiance monitoring (ACRIM) 1, upper atmosphere research satellite (UARS)/ACRIM 2 and ERBS experiments. The space-based irradiance observations are compared to the Mount Wilson Magnetic Plage and Photometric Sunspot Index, which is derived from the area and position of sunspots published by the NOAA World Data Center Solar Geophysical Data Catalog. It is found that the variations in solar UV irradiance were similar during the maximum and minimum of solar cycles 21 and 22. The possible reasons for the differences in the irradiance values during the minima of the two solar cylces are discussed.

Pap, J. M.; Floyd, L.; Lee, R. B.; Parker, D.; Puga, L.; Ulrich, R.; Varadi, F.; Viereck, R.

1997-01-01

34

Long-term migration of the solar sector structure  

NASA Technical Reports Server (NTRS)

The magnetic sector boundaries on the sun and in the solar wind are shown to have a high correlation with winter low pressure systems on earth. The vorticity-area index typically declines by about 10% during several days centered on the time when a sector boundary sweeps past the earth. Evidence that both the sector structure and solar activity levels can be understood as being under the influence of the same regular, internal solar mechanism is presented.

Wolff, C. L.; Heath, D. F.

1979-01-01

35

Long-term variability of solar magnetic fields  

Microsoft Academic Search

The solar magnetic field varies on all time scales. Recent analysis of 600 million year-old Australian varves shows terrestrial evidence for not only the familiar 22-year magnetic cycle, but variations with periods of 300-400 years as well. The Maunder minimum is but one of several long intervals showing atypical levels of solar activity. Recently a 151-day periodicity in flare activity

J. Todd Hoeksema; P. H. Scherrer

1988-01-01

36

Long term stability of optical coatings in close solar environment  

NASA Astrophysics Data System (ADS)

Close observations of the solar atmosphere and surface are required in order to understand the solar activity and its influence on Earth. This task will be performed from Solar Orbiter mission which will reach a very close distance from the Sun: the minimum perihelion distance will be only 0.28 AU. At these distances, the spacecraft and instruments are immersed in a very harsh environment characterized by high temperature, solar wind particles and ions. The stability of the optical coatings at these working conditions are a crucial point in an instrument design and a thorough investigation of the environment effects must be carried out for a secure validation. In this work we present the first experiment carried on in laboratory to establish the effect of solar wind low energy particles bombardment in some optical coatings.

Corso, Alain J.; Zuppella, Paola; Nicolosi, Piergiorgio; Pelizzo, Maria Guglielmina

2011-09-01

37

Long term trends in solar energetic particle events  

NASA Astrophysics Data System (ADS)

Society is increasingly reliant on systems which are vulnerable to Space Weather. Solar energetic particle events are an important aspect of space weather, being particularly damaging to space-borne systems and posing a significant health hazard to astronauts and crews and passengers in aircraft at high latitudes and high altitude. To help quantify our vulnerability to SEP events, various statistical models have been developed which predict quantities such as the peak energetic particle flux in an event, or fluence over a given interval. Generally these models are developed using direct observations of energetic particle fluxes measured on a range of satellite missions since the start of the space age. Reconstructions of solar activity from cosmogenic isotope and geomagnetic activity records show that the space age has coincided with a period of unusually high solar activity, called a grand solar maximum (GSM). However observations of the long and deep minima of solar cycle 23, and the progression of solar cycle 24 have led to predictions that the sun is currently exiting this GSM and probably entering a significantly quieter period of activity. Given these predictions, should we also expect a corresponding variation in the occurrence and severity of SEP events? By using an ~400 year database of very large SEP events determined from the analysis of nitrates in polar ice cores and reconstructions of past solar activity, we present results that suggest a return to more moderate levels of solar activity will enhance the probability of observing very large SEP events. There are uncertainties and some debate about the ice core events; however, additional analysis of a homogenised space age (40 year) database of SEP events also supports the hypothesis that a return to more moderate levels of solar activity will probably lead to a decrease in the event occurrence frequency, but an increase in the average event fluence. Consequently large events such as the "Carrington flare" may become more likely at more average levels of solar activity, with obvious implications for statistical SEP models based on modern data which are largely taken with a GSM.

Barnard, L.; Lockwood, M.; Owens, M. J.; Davis, C. J.; Hapgood, M. A.; Steinhilber, F.

2012-04-01

38

Long-term Consequences of Childhood ADHD on Criminal Activities  

Microsoft Academic Search

Background: Attention Deficit\\/Hyperactivity Disorder (ADHD) is one of the most prevalent mental health problems facing children. Little is known of the long-term consequences of ADHD on young adult outcomes. Aims of the Study: We examine the associations between childhood ADHD symptoms and criminal activities as a young adult. Methods: We use a nationally representative study of US adolescents and logistic

Jason Fletcher; Barbara Wolfe

2009-01-01

39

Long term myriocin treatment increases MRP1 transport activity  

PubMed Central

We investigated the effect of myriocin treatment, which extensively depletes sphingolipids from cells, on multidrug resistance-related protein 1 (MRP1) efflux activity in MRP1 expressing cells and isolated plasma membrane vesicles. Our data reveal that both short term (3 days) and long term (7 days) treatment effectively reduce the cellular sphingolipid content to the same level. Intriguingly, a two-fold increase in MRP1-mediated efflux activity was observed following long term treatment, while short term treatment had no impact. Very similar data were obtained with plasma membrane vesicles isolated from myriocin-treated cells. Exploiting the cell-free vesicle system, Michaelis–Menten analysis revealed that the intrinsic MRP1 activity remained unaltered; however, the fraction of active transporter molecules increased. We demonstrate that the latter effect is due to an enhanced recruitment of MRP1 into lipid raft fractions, thereby promoting MRP1 activity.

Meszaros, Peter; Klappe, Karin; van Dam, Annie; Ivanova, Pavlina T.; Milne, Stephen B.; Myers, David S.; Brown, H. Alex; Permentier, Hjalmar; Hoekstra, Dick; Kok, Jan W.

2013-01-01

40

High-amplitude, long-term X-ray variability in the solar-type star HD 81809: The beginning of an X-ray activity cycle?  

Microsoft Academic Search

We present the initial results from our XMM-Newton program aimed at searching for X-ray activity cycles in solar-type stars. HD 81809 is a G2-type star (somewhat more evolved than the Sun, and with a less massive companion) with a pronounced 8.2 yr chromospheric cycle, as evident from from the Mt. Wilson program data. We present here the results from the

F. Favata; G. Micela; S. L. Baliunas; J. H. M. M. Schmitt; M. Güdel; F. R. Harnden Jr.; S. Sciortino; R. A. Stern

2004-01-01

41

Long-Term Solar Irradiance Variations Over Solar Cycles 21 to 23  

NASA Astrophysics Data System (ADS)

In this paper we present the work accomplished during the three years long LWS TR&T grant (NAG5-13513). As part of the work we addressed the following questions: (1) How does various total irradiance composites relate to each other? (2) How well various solar indices can be used as surrogates for solar irradiance variations? As part of the research under question (1) we have constructed a new composite using both the Nimbus-7 and ERBS/ERBE total irradiance measurements. While the PMOD composite has shown a symmetrical long-term total irradiance variations with the same maximum and minimum level over the last three consecutive solar cycles, the ACRIM composite has shown a slow 0.05% secular trend from the minimum of cycle~21 to the minimum of cycle~22. Our reconstruction indicates a much smaller trend (about half of the one shown by the ACRIM composite). Our results also show that the linear relation between solar variability, as represented by total irradiance variations, and solar activity, as represented by magnetic indices, breaks down during the maximum and minimum of solar cycles 23. While most of the magnetic indices showed that cycle 23 was a weak cycle, both total and UV irradiances reached as high maxima as during the previous strong cycles. Furthermore, we have found that during the declining portion of cycle 23, total irradiance already reached minimum activity levels, while surrogates used in the empirical models were still in their declining phase. Considering the lack of good surrogates and physical understanding of the underlying mechanisms of irradiance variations, we will address briefly the perspectives of future space-based irradiance experiments.

Pap, J. M.

2006-12-01

42

Quantitative study of long-term solar and climatic changes  

NASA Technical Reports Server (NTRS)

Long term variations in the diameter and the shape of the Sun were studied. Daily observations of the Sun's diameter made at the Greenwich Observatory between 1836 and 1953 were analysed and interpreted. The data was converted into digital form and then screened and processed. It was found that the horizontal diameter of the Sun measured at Greenwich appears to have decreased systematically between 1880 and 1953 at a rate of 1.2 plus or minus 0.6 minutes of arc per century.

Eddy, J. A.

1982-01-01

43

The long-term variations of the solar and heliospheric fields  

NASA Astrophysics Data System (ADS)

The heliospheric field is determined by the largest-scale patterns of magnetism at the solar surface, dominated by the lower-latitude active regions during cycle maximum, and by the circumpolar fields during cycle minimum. To study these patterns, we simulate the evolution of the magnetic field at the solar surface and in the heliosphere during the last 340 years. We conclude that, contrary to current thinking, the observed magnetic flux in the polar regions of the Sun cannot be understood as merely a long-term accumulation of active-region decay products from a dynamo that modulates only the rate at which flux emerges from cycle to cycle. We suggest that simulation and observation may be reconciled if the high-latitude solar field decays on a time scale comparable to that of the sunspot cycle.

Schrijver, Carolus J.; De Rosa, Marc L.; Title, Alan M.

2002-10-01

44

Long term storage of relativistic particles in the solar corona  

Microsoft Academic Search

A model is presented which shows that large numbers of energetic electrons (0.3-> 10 MeV) and protons (1–30 MeV) can be stored in the solar corona at altitudes around 3 × 105 km for periods in excess of 5 days. Specific reference is made to the time period July 6–16 1968 as an excellent example of energetic solar particle storage.

George M. Simnett; Stephen S. Holt

1971-01-01

45

Long-term response of total ozone content at different latitudes of the Northern and Southern Hemispheres caused by solar activity during 1958-2006 (results of regression analysis)  

NASA Astrophysics Data System (ADS)

Solar activity influences on atmospheric photochemical system via its changebale electromag-netic flux with eleven-year period and also by energetic particles during solar proton event (SPE). Energetic particles penetrate mostly into polar regions and induce additional produc-tion of NOx and HOx chemical compounds, which can destroy ozone in photochemical catalytic cycles. Solar irradiance variations cause in-phase variability of ozone in accordance with photo-chemical theory. However, real ozone response caused by these two factors, which has different physical nature, is not so clear on long-term time scale. In order to understand the situation multiply linear regression statistical method was used. Three data series, which covered the period 1958-2006, have been used to realize such analysis: yearly averaged total ozone at dif-ferent latitudes (World Ozone Data Centre, Canada, WMO); yearly averaged proton fluxes with E¿ 10 MeV ( IMP, GOES, METEOR satellites); yearly averaged numbers of solar spots (Solar Data). Then, before the analysis, the data sets of ozone deviations from the mean values for whole period (1958-2006) at each latitudinal belt were prepared. The results of multiply regression analysis (two factors) revealed rather complicated time-dependent behavior of ozone response with clear negative peaks for the years of strong SPEs. The magnitudes of such peaks on annual mean basis are not greater than 10 DU. The unusual effect -positive response of ozone to solar proton activity near both poles-was discovered by statistical analysis. The pos-sible photochemical nature of found effect is discussed. This work was supported by Russian Science Foundation for Basic Research (grant 09-05-009949) and by the contract 1-6-08 under Russian Sub-Program "Research and Investigation of Antarctica".

Krivolutsky, Alexei A.; Nazarova, Margarita; Knyazeva, Galina

46

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

47

Solar cycle and global long term variations of stratospheric ozone  

NASA Astrophysics Data System (ADS)

We analyze in this work four available sets of stratospheric ozone measurements obtained by ground UV-B sun spectrophotometer Dobson type in the period from 1957 until 1997. By the analysis of these sets of ozone data and satellite observations we can see a decreasing intensity at all these latitudes (Belsk, Murmansk, Tbilisi and C. Paulista), given a global mean rate ~ 10 % during the last three solar cycles. We saw also correlations between ozone variations and sunspot number

Martin, I. M.; Toroshelidze, T.; Alves, W. E.; Mello, M. G. S.; Gusev, A. Á.; Pugacheva, G. I.

1999-01-01

48

Long-term physical activity trends in breast cancer survivors  

PubMed Central

Background Physical activity is associated with reduced mortality and higher quality of life in breast cancer survivors; however, limited data on the prevalence of activity and long-term trends after diagnosis are available. Methods A multi-ethnic cohort of 631 women (18–64 years) with stage 0-IIIA breast cancer were followed for 10 years. Recreational aerobic activity (MET-hrs/week) was ascertained for the year before diagnosis (baseline), 24 months, 5 and 10 years after enrollment. Women were classified according to U.S. physical activity guidelines (?150 mins/week moderate or ?75 mins/week vigorous activity). The odds ratios (OR) for meeting guidelines at 5 and 10 years according to baseline factors was estimated using logistic regression. The change in MET-hrs/wk was predicted using linear regression. Results Pre-diagnosis, 34% of women met physical activity guidelines; 34.0%, 39.5%, and 21.4% met guidelines at 24 months, 5 years, and 10 years post-enrollment, respectively. Fewer than 8% of survivors met guidelines at all follow-up periods. Over 10 years, recreational aerobic activity decreased by a mean(SD) 4.3(16.2) MET-hrs/wk.. Meeting guidelines pre-diagnosis was strongly associated with meeting guidelines at 5 years [OR (95% CI): 2.76 (1.85–4.1)] and 10 years [OR (95% CI): 3.35 (2.13–5.28)]. No other demographic or prognostic factors were significantly associated with the 10-year change in MET-hrs/wk. Conclusion The vast majority of early breast cancer survivors do not meet national exercise recommendations 10 years post-diagnosis. Impact Physical activity levels are low in breast cancer survivors across the 10 years post-diagnosis, yet the predictors of activity in this population remain poorly understood.

Mason, Caitlin; Alfano, Catherine M.; Smith, Ashley Wilder; Wang, C.Y.; Neuhouser, Marian L.; Duggan, Catherine; Bernstein, Leslie; Baumgartner, Kathy B.; Baumgartner, Richard N.; Ballard-Barbash, Rachel; McTiernan, Anne

2013-01-01

49

Long-term temperature effects on GaAs solar cells  

Microsoft Academic Search

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

J. H. Heinbockel; K. H. Hong

1979-01-01

50

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

51

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

52

A Model of Long Term Variability of Solar UV and EUV Irradiance  

NASA Astrophysics Data System (ADS)

An empirical model of solar UV spectral irradiance has been developed at the Naval Research Laboratory with support from the NASA-LWS program. This model uses observed spectral radiance from the HRTS-9 rocket and CaII-K images to identify solar surface features. The initial wavelength range covered 18 nm near Mg II at 280 nm. This range is being expanded to cover wavelengths from 120 to 400 nm using SKYLAB data and below 120nm using TIMED/SEE data and model spectra derived from SOHO/EIT observations. The long wavelength portion of the model identifies three surface features: quiet-sun, active-sun, and sunspots and applies spectra for these features. The model requires detailed knowledge of the center-to-limb variation and a calibration derived from observations of several quiet days by SUSIM and SOLSTICE. The short wavelength portion of the model uses linear regressions to estimate the solar EUV spectrum using correlations between the NOAA Mg II index and observed or model EUV spectra. The regression analysis covers a full solar cycle and the model output is a solar EUV spectrum at 1 nm resolution from17-55 nm. Resulting spectra are compared with measurements of solar EUV flux to estimate model accuracy and variability. Model efforts have concentrated on the period 1990-1995 but this is currently being extended to estimate spectral irradiance back to the early 1900's for use as input to long term climate models. This will be done using the recently digitized Ca II K images from Mt Wilson Observatory (MWO) which extend from 1915 to 1985. In this presentation, we review the model and model inputs, output UV/EUV spectra, and the methods being developed for correction of the MWO images.

Morrill, J.; McMullin, D.; Ulrich, R.

2006-12-01

53

Future Long-term Measurements of Solar Spectral Irradiance by JPSS TSIS  

NASA Astrophysics Data System (ADS)

To advance scientific understanding of how solar variability affects climate processes it is important to maintain accurate, long-term records of solar irradiance. Continuation of solar spectral irradiance (SSI) measurements is needed to characterize poorly understood wavelength-dependent climate processes. Measurement challenges in quantifying the influence of SSI variability on climate are achieving sufficient radiometric absolute accuracy and maintaining the long-term relative accuracy. The Total and Spectral Solar Irradiance Sensor (TSIS) is a dual-instrument package that will acquire solar irradiance as part of the Joint Polar Satellite System (JPSS). The TSIS Spectral Irradiance Monitor (SIM) instrument will continue the SSI measurements that began with the SORCE SIM in 2003. The TSIS SIM incorporates design and calibration improvements to better quantify long-term SSI variability. Specific improvements include the pre-launch SI-traceable calibration, the measurement precision, and the long-term relative stability needed to meet the requirements for establishing a climate record of SSI into the future. To quantify the absolute accuracy over the full spectral range, we have developed a SIM Radiometer Facility (SIMRF) utilizing the NIST Spectral Irradiance and Radiance Responsivity Calibrations using Uniform Sources (SIRCUS). This comprehensive facility includes tuneable laser light sources from the ultraviolet to the near infrared matched in radiant power to the solar spectrum and tied to a cryogenic radiometer traceable to the NIST Primary Optical Watt Radiometer (POWR). The full characterization and calibration follows a measurement equation approach at the unit-level for full validation of the end-to-end performance at the instrument-level to achieve a combined standard uncertainty of 0.25% .

Richard, E. C.; Harber, D.; Harder, J. W.; Pilewskie, P.; Brown, S.; Smith, A.; Lykke, K.

2011-12-01

54

Saturn suprathermal O2+ and mass-28+ molecular ions: Long-term seasonal and solar variation  

NASA Astrophysics Data System (ADS)

Suprathermal singly charged molecular ions, O2+ (at ~32 Da/e) and the Mass-28 ion group 28M+ (ions at ~28 Da/e, with possible contributions from C2H5+, HCNH+, N2+, and/or CO+), are present throughout Saturn's ~4-20 Rs (1 Saturn radius, Rs = 60,268 km) near-equatorial magnetosphere from mid-2004 until mid-2012. These ~83-167 keV/e heavy ions measured by Cassini's CHarge-Energy-Mass Spectrometer have long-term temporal profiles that differ from each other and differ relative to the dominant water group ions, W+ (O+, OH+, H2O+, and H3O+). O2+/W+, initially ~0.05, declined steadily until equinox in mid-2009 by a factor of ~6, and 28M+/W+, initially ~0.007, declined similarly until early-2007 by a factor of ~2. The O2+/W+ decline is consistent with Cassini's in situ ring-ionosphere thermal ion measurements, and with proposed and modeled seasonal photolysis of Saturn's rings for thermal O2 and O2+. The water ice-dominated main rings and Enceladus plume depositions thereon are the two most likely O2+ sources. Enceladus' dynamic plumes, though, have no known long-term dependence. After declining, O2+/W+ and 28M+/W+ levels remained low until late-2011 when O2+/W+ increased, but 28M+/W+ did not. The O2+/W+ increase was steady and became statistically significant by mid-2012, indicating a clear increase after a decline, that is, a possibly delayed O2+ "seasonal" recovery. Ring insolation is driven by solar UV flux which itself varies with the sun's 11 year activity cycle. The O2+/W+ and 28M+/W+ declines are consistent with seasonal ring insolation. No O2+/W+ response to the late-2008 solar-cycle UV minimum and recovery is evident. However, the O2+/W+ recovery from the postequinox baseline levels in late-2011 coincided with a strong solar UV enhancement. We suggest a scenario/framework in which the O2+ observations can be understood.

Christon, S. P.; Hamilton, D. C.; Difabio, R. D.; Mitchell, D. G.; Krimigis, S. M.; Jontof-Hutter, D. S.

2013-06-01

55

HelioClim: a long -term database on solar radiation for Europe and Africa  

Microsoft Academic Search

An information system, called HelioClim, is available for answering the needs for long-term time-series of solar radiation data. Daily irradiation values are available over Europe, Africa and Atlantic Ocean, from 1985 onwards. This database is accessible through the Soda Web service (http:\\/\\/www.s oda-is.com) on a free basis. Meteosat satellites images are used to produce this climatological database. The method Heliosat-2

S. Cros; M. Albuisson; M. Lefèvre; C. Rigollier; L. Wald

56

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

57

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

58

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

59

Imprint of long-term solar signal in groundwater recharge fluctuation rates from Northwest China  

NASA Astrophysics Data System (ADS)

spectral and statistical analyses of a 700 yearlong temporal record of groundwater recharge from the dry lands, Badain Jaran Desert (Inner Mongolia) of Northwest China reveal a stationary harmonic cycle at ~200 ± 20 year. Interestingly, the underlying periodicity in groundwater recharge fluctuations is similar to those of solar-induced climate cycle "Suess wiggles" and appears to be coherent with phases of the climate fluctuations and solar cycles. Matching periodicity of groundwater recharge rates and solar and climate cycles renders a strong impression that solar-induced climate signals may act as a critical amplifier for driving the underlying hydrographic cycle through the common coupling of long-term Sun-climate groundwater linkages.

Tiwari, R. K.; Rajesh, Rekapalli

2014-05-01

60

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

61

Long-term helicity evolution in NOAA active region 8100  

NASA Astrophysics Data System (ADS)

Magnetic helicity is the topological parameter used to describe the structure in the magnetic field and has become increasingly important in coronal studies. Helicity is well preserved in the corona even under non-ideal MHD conditions (see Biskamp 1993), and the Sun can avoid endless accumulation of helicity by ejecting it via the launch of coronal mass ejections (eg. Rust 1994; Low 1996; Devore 2000). Computations are made for NOAA active region 8100 to determine the coronal helicity and helicity injected into the region by differential rotation. These values are then compared to the total amount of helicity lost via coronal mass ejections to test whether differential rotation can inject a significant amount of helicity into the corona. It is found that differential rotation cannot inject a significant amount of helicity to be a viable source for the coronal mass ejection activity. Instead, helicity is likely to be brought into the corona by the emergence of twisted and distorted flux tubes.

Green, L. M.; López Fuentes, M. C.; Mandrini, C. H.; van Driel-Gesztelyi, L.; Démoulin, P.

2002-03-01

62

Long-term change in the organization of inventive activity.  

PubMed

Relying on a quantitative analysis of the patenting and assignment behavior of inventors, we highlight the evolution of institutions that encouraged trade in technology and a growing division of labor between those who invented new technologies and those who exploited them commercially over the nineteenth and early-twentieth centuries. At the heart of this change in the organization of inventive activity was a set of familiar developments which had significant consequences for the supply and demand of inventions. On the supply side, the growing complexity and capital intensity of technology raised the amount of human and physical capital required for effective invention, making it increasingly desirable for individuals involved in this activity to specialize. On the demand side, the growing competitiveness of product markets induced firms to purchase or otherwise obtain the rights to technologies developed by others. These increasing incentives to differentiate the task of invention from that of commercializing new technologies depended for their realization upon the development of markets and other types of organizational supports for trade in technology. The evidence suggests that the necessary institutions evolved first in those regions of the country where early patenting activity had already been concentrated. A self-reinforcing process whereby high rates of inventive activity encouraged the evolution of a market for technology, which in turn encouraged greater specialization and productivity at invention as individuals found it increasingly feasible to sell and license their discoveries, appears to have been operating. This market trade in technological information was an important contributor to the achievement of a high level of specialization at invention well before the rise of large-scale research laboratories in the twentieth century. PMID:8917480

Lamoreaux, N R; Sokoloff, K L

1996-11-12

63

Long-term change in the organization of inventive activity  

PubMed Central

Relying on a quantitative analysis of the patenting and assignment behavior of inventors, we highlight the evolution of institutions that encouraged trade in technology and a growing division of labor between those who invented new technologies and those who exploited them commercially over the nineteenth and early-twentieth centuries. At the heart of this change in the organization of inventive activity was a set of familiar developments which had significant consequences for the supply and demand of inventions. On the supply side, the growing complexity and capital intensity of technology raised the amount of human and physical capital required for effective invention, making it increasingly desirable for individuals involved in this activity to specialize. On the demand side, the growing competitiveness of product markets induced firms to purchase or otherwise obtain the rights to technologies developed by others. These increasing incentives to differentiate the task of invention from that of commercializing new technologies depended for their realization upon the development of markets and other types of organizational supports for trade in technology. The evidence suggests that the necessary institutions evolved first in those regions of the country where early patenting activity had already been concentrated. A self-reinforcing process whereby high rates of inventive activity encouraged the evolution of a market for technology, which in turn encouraged greater specialization and productivity at invention as individuals found it increasingly feasible to sell and license their discoveries, appears to have been operating. This market trade in technological information was an important contributor to the achievement of a high level of specialization at invention well before the rise of large-scale research laboratories in the twentieth century.

Lamoreaux, Naomi R.; Sokoloff, Kenneth L.

1996-01-01

64

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.

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

2014-01-01

65

Arizona Long Term Care Gerontology Center (Overview of Scope and Nature of the Center's Activities).  

National Technical Information Service (NTIS)

The text provides an overview of the scope and nature of the Long-Term Gerontology Center's activities from 1980 through 1985 in each program area: education/training, research, service model development, technical assistance, information dissemination. T...

T. H. Koff

1985-01-01

66

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

67

Long-term dynamics of solar cycle, geomagnetic reversals and fluctuations of dynamo governing parameters  

NASA Astrophysics Data System (ADS)

As a matter of fact, cyclic behaviour of salar activity demonstrates a dynamics on the timescales which are much longer then the cycle period. From the other hand, magnetostratigraphic timescale shows a complicated long-term evolution of geomeanetic field on the timescales which are much longer then the presumed geodynamo timescale. A model which relate such phenomenae with random variations of alpha-effect (or other governing mean-field dynamo parameters) is suggested.

Sokoloff, D.

2012-04-01

68

Solar irradiance at the earth's surface: long-term behavior observed at the South Pole  

NASA Astrophysics Data System (ADS)

This research examines a 17-year database of UV-A (320-400 nm) and visible (400-600 nm) solar irradiance obtained by a scanning spectroradiometer located at the South Pole. The goal is to define the variability in solar irradiance reaching the polar surface, with emphasis on the influence of cloudiness and on identifying systematic trends and possible links to the solar cycle. To eliminate changes associated with the varying solar elevation, the analysis focuses on data averaged over 30-35 day periods centered on each year's austral summer solstice. The long-term average effect of South Polar clouds is a small attenuation, with the mean measured irradiances being about 5-6% less than the clear-sky values, although at any specific time clouds may reduce or enhance the signal that reaches the sensor. The instantaneous fractional attenuation or enhancement is wavelength dependent, where the percent deviation from the clear-sky irradiance at 400-600 nm is typically 2.5 times that at 320-340 nm. When averaged over the period near each year's summer solstice, significant correlations appear between irradiances at all wavelengths and the solar cycle as measured by the 10.7 cm solar radio flux. An approximate 1.8 ± 1.0% decrease in ground-level irradiance occurs from solar maximum to solar minimum for the wavelength band 320-400 nm. The corresponding decrease for 400-600 nm is 2.4 ± 1.9%. The best-estimate declines appear too large to originate in the sun. If the correlations have a geophysical origin, they suggest a small variation in atmospheric attenuation with the solar cycle over the period of observation, with the greatest attenuation occurring at solar minimum.

Frederick, J. E.; Hodge, A. L.

2011-02-01

69

Solar irradiance at the Earth's surface: long-term behavior observed at the South Pole  

NASA Astrophysics Data System (ADS)

This research examines a 17-year database of UV-A (320-400 nm) and visible (400-600 nm) solar irradiance obtained by a scanning spectroradiometer located at the South Pole. The goal is to define the variability in solar irradiance reaching the polar surface, with emphasis on the influence of cloudiness and on identifying systematic trends and possible links to the solar cycle. To eliminate changes associated with the varying solar elevation, the analysis focuses on data averaged over 30-35 day periods centered on each year's austral summer solstice. The long-term average effect of South Polar clouds is a small attenuation, with the mean measured irradiances being about 5-6% less than the clear-sky values, although at any specific time clouds may reduce or enhance the signal that reaches the sensor. The instantaneous fractional attenuation or enhancement is wavelength dependent, where the percent deviation from the clear-sky irradiance at 400-600 nm is typically 2.5 times that at 320-340 nm. When averaged over the period near each year's summer solstice, significant correlations appear between irradiances at all wavelengths and the solar cycle as measured by the 10.7 cm solar radio flux. An approximate 1.8 ± 1.0% decrease in ground-level irradiance occurs from solar maximum to solar minimum for the wavelength band 320-400 nm. The corresponding decrease for 400-600 nm is 2.4 ± 1.9%. The best-estimate declines appear too large to originate in the sun. If the correlations have a geophysical origin, they suggest a small variation in atmospheric attenuation with the solar cycle over the period of observation, with the greatest attenuation occurring at solar minimum.

Frederick, J. E.; Hodge, A. L.

2010-11-01

70

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

71

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

72

Solar cycle dynamics of solar, magnetospheric, and heliospheric particles, and long-term atmospheric coupling: SAMPLEX  

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, 1995 through July 1, 1996. Bibliographic entries for 1995 and 1996 to date (July 1996) are included. The SAMPEX science team was extremely active, with 20 articles published or submitted to refereed journals, 18 papers published in their entirety in Conference Proceedings, and 53 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 of anomalous cosmic rays, solar energetic particles, magnetospheric precipitating electrons, trapped H and He isotopes, and data analysis activities.

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

1996-01-01

73

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

74

Tibial stress fractures in an active duty population: long-term outcomes.  

PubMed

Tibial stress fractures are a common overuse injury among military recruits. The purpose of this study was to determine what, if any, long-term effects that tibial stress fractures have on military personnel with respect to physical activity level, completion of military training, recurrence of symptoms, and active duty service. Twenty-six military recruits included in a previous tibial stress fracture study were contacted 10 years after initial injury and asked a series of questions related to any long-term consequences of their tibial stress fracture. Of the 13 patients available for contact, no patients reported any necessary limited duty while on active duty, and no patient reported being separated or discharged from the military as a result of stress fracture. Tibial stress fractures in military recruits are most often an isolated injury and do not affect ability to complete military training or reflect a long-term need for decreased physical activity. PMID:23449055

Kilcoyne, Kelly G; Dickens, Jonathan F; Rue, John-Paul

2013-01-01

75

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

76

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

77

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

78

Long-term temperature effects on gaas solar cells. Final report, 1 January 1978-15 April 1979  

Microsoft Academic Search

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

J. H. Heinbockel; K. H. Hong

1979-01-01

79

Long-term patterns of solar irradiance forcing in model experiments and proxy based surface temperature reconstructions  

Microsoft Academic Search

Comparisons are made of long-term empirical and model-estimated patterns of solar irradiance forcing during a 200-year period (1650-1850), which precedes any apparent anthropogenic influence on climate. This interval encompasses a considerable range (approximately 4 W\\/m2) of estimated variation in solar output, including the \\

A. M. Waple; M. Mann; R. Bradley

2002-01-01

80

Kerava Solar Village - A Solar Assisted Heat Pump System with Long-Term Heat Storage.  

National Technical Information Service (NTIS)

The Kerava solar village is the first regional building complex in Finland with a combined solar heating and heat pump system using seasonal storage. Besides the operational principles, we present the findings of a cost, performance and sensitivity analys...

R. Maekinen P. D. Lund

1983-01-01

81

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

82

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

83

Long-Term Dynamics of Small Bodies in the Solar System  

NASA Astrophysics Data System (ADS)

As part of the NASA Planetary Geology and Geophysics program, Prof. Norm Murray (CITA (Canadian Institute of Theoretical Astrophysics)) and I have been conducting investigations of the long-term dynamics of small bodies in the outer solar system. This grant, and its successor NAG5-10365, supports travel for collaboration by the Investigators and also supports Murray during an annual one month visit to the CfA (Harvard-Smithsonian Center for Astrophysics) 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 (NEO). 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 (American Association for the Advancement of Science). This award singles out one paper published in Science each year for distinction. A list of grant-related publications is presented, with abstracts included.

Holman, Matthew J.

2002-04-01

84

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 (Canadian Institute of Theoretical Astrophysics)) and I have been conducting investigations of the long-term dynamics of small bodies in the outer solar system. This grant, and its successor NAG5-10365, supports travel for collaboration by the Investigators and also supports Murray during an annual one month visit to the CfA (Harvard-Smithsonian Center for Astrophysics) 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 (NEO). 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 (American Association for the Advancement of Science). This award singles out one paper published in Science each year for distinction. A list of grant-related publications is presented, with abstracts included.

Holman, Matthew J.; Grant, John (Technical Monitor)

2002-01-01

85

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

86

Episodic hypoxia evokes long-term facilitation of genioglossus muscle activity in neonatal rats  

Microsoft Academic Search

The aim of this study was to determine if episodic hypoxia evokes persistent increases of genioglossus muscle (GG) activity, termed long-term facilitation (LTF), in neonatal rats in vivo. Experiments were performed on anaesthetized, spontaneously breathing, intubated neonatal rats (postnatal days (P) 3-7), divided into three groups. The first group (n = 8) was subjected to three 5-min periods of hypoxia

Leanne C. McKay; Wiktor A. Janczewski; Jack L. Feldman

2004-01-01

87

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

88

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

89

Long-term variations of the solar wind density - velocity relation.  

NASA Astrophysics Data System (ADS)

The relation between density and velocity of the solar wind is determined for the individual phases of solar activity cycles 20 and 21, using daily averaged values of the solar wind parameters (November 1963 -- May 1980, Bartels rotations No.s 1783-2006). It was found that the particle concentration decreases in all analysed phases of the two solar cycles with increasing solar wind velocity. In most phases of cycles 20 and 21 (with the exception of the ascending branch of cycle 20), the density decreases as n ˜V-1.5. As regards the quiescent solar wind with no marked velocity gradients, it was found that n ˜V(1.6-1.7). During the ascending phase, it appears that n ˜V-1.1 is realistic. In both cycles, 20 and 21, it was found that the particle density of the solar wind is higher on the average (about 1.5 times) in the solar activity minimum than in its maximum.

Kul?ár, L.

90

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

91

11-year Solar Cycle and Long Term Trend in OH airglow Temperature Observations at the South Pole Station, Antarctica  

Microsoft Academic Search

We have examined Michelson Interferometer OH airglow temperature data to investigate solar cycle and long-term variations of mesospheric temperatures at the South Pole Station, Antarctica (90o S). The aforementioned MI has been making observations of temperature and airglow emissions since 1992 during austral winter night. These continuous measurements during the six months of each polar winter allow us to investigate

I. Azeem; G. G. Sivjee; Y. Won; C. Mutiso

2005-01-01

92

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

Microsoft Academic Search

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

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

2010-01-01

93

Accuracy of the European solar water heater test procedure. Part 2: Prediction of long-term performance  

Microsoft Academic Search

This paper continues the evaluation of the European test procedure for solar water heaters, by considering what consequences the errors of the parameters (derived in Part 1, the companion paper) will have for the prediction of the long-term performance. A simple criterion is derived for the required length of the test period, as a function of climatic variables and desired

A. Rabl; M. J. Carvalho; M. Collares-Pereira; B. Bourges

1991-01-01

94

Long-term stability for cobalt-based dye-sensitized solar cells obtained by electrolyte optimization.  

PubMed

A significant improvement in the long-term stability for cobalt-based dye-sensitized solar cells (DSCs) under light-soaking conditions has been achieved by optimization of the composition of tris(2,2'-bipyridine) Co(ii)/Co(iii) electrolytes. The effects of component exchanges and changes were also studied during the optimization process. PMID:24788679

Gao, Jiajia; Bhagavathi Achari, Muthuraaman; Kloo, Lars

2014-06-14

95

Long-term health benefits of physical activity - a systematic review of longitudinal studies  

PubMed Central

Background The treatment of noncommunicable diseases (NCD), like coronary heart disease or type 2 diabetes mellitus, causes rising costs for the health system. Physical activity is supposed to reduce the risk for these diseases. Results of cross-sectional studies showed that physical activity is associated with better health, and that physical activity could prevent the development of these diseases. The purpose of this review is to summarize existing evidence for the long-term (>5 years) relationship between physical activity and weight gain, obesity, coronary heart disease, type 2 diabetes mellitus, Alzheimer’s disease and dementia. Methods Fifteen longitudinal studies with at least 5-year follow up times and a total of 288,724 subjects (>500 participants in each study), aged between 18 and 85 years, were identified using digital databases. Only studies published in English, about healthy adults at baseline, intentional physical activity and the listed NCDs were included. Results The results of these studies show that physical activity appears to have a positive long-term influence on all selected diseases. Conclusions This review revealed a paucity of long-term studies on the relationship between physical activity and the incidence of NCD.

2013-01-01

96

Long-term patterns of solar irradiance forcing in model experiments and proxy based surface temperature reconstructions  

Microsoft Academic Search

Comparisons are made of long-term empirical and model-estimated patterns of solar irradiance forcing during a 200-year period (1650-1850), which precedes any apparent anthropogenic influence on climate. This interval encompasses a considerable range (approxi- mately 4 W\\/m2) of estimated variation in solar output, including the ''Maunder'' and ''Dalton'' Minima of so- lar irradiance, and an intervening interval of relatively high values

A. M. Waple; R. S. Bradley; M. E. Mann

2002-01-01

97

Long-term field test of solar PV power generation using one-axis 3-position sun tracker  

Microsoft Academic Search

The 1 axis-3 position (1A-3P) sun tracking PV was built and tested to measure the daily and long-term power generation of the solar PV system. A comparative test using a fixed PV and a 1A-3P tracking PV was carried out with two identical stand-alone solar-powered LED lighting systems. The field test in the particular days shows that the 1A-3P tracking

B. J. Huang; W. L. Ding; Y. C. Huang

2011-01-01

98

Solar cycle signature and secular long-term trend in OH airglow temperature observations at South Pole, Antarctica  

Microsoft Academic Search

We have examined Michelson Interferometer OH airglow temperature data to investigate solar cycle and long-term variations of mesospheric temperatures at South Pole Station (SPS), Antarctica (90°S). The data set used here is continuous (24 hours a day) and taken during 1994-2004 austral winters. We have used a Multiple Linear Regression (MLR) technique to elucidate solar cycle and the trend term

S. M. I. Azeem; G. G. Sivjee; Y.-I. Won; Charles Mutiso

2007-01-01

99

Solar cycle signature and secular long-term trend in OH airglow temperature observations at South Pole, Antarctica  

Microsoft Academic Search

We have examined Michelson Interferometer OH airglow temperature data to investigate solar cycle and long-term variations of mesospheric temperatures at South Pole Station (SPS), Antarctica (90°S). The data set used here is continuous (24 hours a day) and taken during 1994–2004 austral winters. We have used a Multiple Linear Regression (MLR) technique to elucidate solar cycle and the trend term

S. M. I. Azeem; G. G. Sivjee; Y.-I. Won; Charles Mutiso

2007-01-01

100

Long term endurance test and contact degradation of CIGS solar cells  

NASA Astrophysics Data System (ADS)

CIGS is the most promising technology for thin-film solar cells with record efficiencies of 20.4 % on laboratory scale and 17.8 % aperture area efficiency on a 900 cm² module. Another important factor besides the cell efficiency is the reliability and long term stability of the manufactured modules, which can be assessed by accelerated ageing. In this contribution the accelerated ageing of CIGS mini modules has been investigated. Therefore, modules were dark annealed under dry heat conditions at different temperatures. During the endurance test a positive or negative bias was applied to the cells. In regular intervals the IV- and CV-characteristics were measured at room temperature. After an overall stress time of 3500 h the IV-characteristics were determined under different illumination conditions (intensity, spectral illumination). Our previous publications suggest a barrier at the back contact to explain the observed parameter drifts. This contribution is focused on the influence of different bias conditions during the endurance test on the generation of a back diode and on the change of the acceptor concentration. These parameter drifts have an impact on the open circuit voltage, fill factor and on the appearance of a cross over between dark and illuminated IV-characteristics. The interpretation of the observed parameter drifts was supported by SCAPS simulations based on the above mentioned back barrier model. As an outcome of the simulations signatures for the existence of a back barrier diode were established. IVmeasurements, temperature dependent Voc measurements and SunsVoc measurements are helpful means to detect such back diodes.

Ott, Thomas; Schönberger, Francillina; Walter, Thomas; Hariskos, Dimitrios; Kiowski, Oliver; Schäffler, Raymund

2013-09-01

101

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.

102

Coincident Activity of Converging Pathways Enables Simultaneous Long-Term Potentiation and Long-Term Depression in Hippocampal CA1 Network In Vivo  

PubMed Central

Memory is believed to depend on activity-dependent changes in the strength of synapses, e.g. long-term potentiation (LTP) and long-term depression (LTD), which can be determined by the sequence of coincident pre- and postsynaptic activity, respectively. It remains unclear, however, whether and how coincident activity of converging efferent pathways can enable LTP and LTD in the pathways simultaneously. Here, we report that, in pentobarbital-anesthetized rats, stimulation (600 pulses, 5 Hz) to Schaffer preceding to commissural pathway within a 40-ms timing window induced similar magnitudes of LTP in both pathways onto synapses of CA1 neurons, with varied LTP magnitudes after reversal of the stimulation sequence. In contrast, in urethane-anesthetized or freely-moving rats, the stimulation to Schaffer preceding to commissural pathway induced Schaffer LTP and commissural LTD simultaneously within a 40-ms timing window, without affecting synaptic efficacy in the reversed stimulation sequence. Coincident activity of Schaffer pathways confirmed the above findings under pentobarbital and urethane anesthesia. Thus, coincident activity of converging afferent pathways tends to switch the pathways to be LTP only or LTP/LTD depending on the activity states of the hippocampus. This network rule strengthens the view that activity-dependent synaptic plasticity may well contribute to memory process of the hippocampal network with flexibility or stability from one state to another.

Cao, Jun; Zhang, Xia; Xu, Lin

2008-01-01

103

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

104

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

105

Phrenic Long-Term Facilitation Requires Spinal Serotonin Receptor Activation and Protein Synthesis  

Microsoft Academic Search

Respiratory long-term facilitation (LTF) is a form of serotonin- dependent plasticity induced by intermittent hypoxia. LTF is manifested as a long-lasting increase in respiratory amplitude (and frequency) after the hypoxic episodes have ended. We tested the hypotheses that LTF of phrenic amplitude requires spinal serotonin receptor activation and spinal protein synthe- sis. A broad-spectrum serotonin receptor antagonist (methy- sergide) or

L. Baker-Herman; Gordon S. Mitchell

2002-01-01

106

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

107

Effects of long-term physical activity on cardiac structure and function: a twin study.  

PubMed

Previous studies have shown that athletic training or other physical activity causes structural and functional adaptations in the heart, but less is known how long-term physical activity affects heart when genetic liability and childhood environment are taken into account. The aim of this study was to investigate the effects of long-term physical activity vs. inactivity on cardiac structure and function in twin pairs discordant for physical activity for 32 years. Twelve same-sex twin pairs (five monozygotic and seven dizygotic, 50-67 years) were studied as a part of the TWINACTIVE study. Discordance in physical activity was initially determined in 1975 and it remained significant throughout the follow-up. At the end of the follow-up in 2007, resting echocardiographic and electrocardiographic measurements were performed. During the follow-up period, the active co-twins were on average 8.2 (SD 4.0) MET hours/day more active than their inactive co-twins (p < 0.001). At the end of the follow-up, resting heart rate was lower in the active than inactive co-twins [59 (SD 5) vs. 68 (SD 10) bpm, p=0.03]. The heart rate-corrected QT interval was similar between the co-twins. Also, there was a tendency for left ventricular mass per body weight to be greater and T wave amplitude in lead II to be higher in the active co-twins (18% and 15%, respectively, p=0.08 for both). Similar trends were found for both monozygotic and dizygotic twin pairs. In conclusion, the main adaptation to long- term physical activity is lowered resting heart rate, even after partially or fully controlling for genetic liability and childhood environment. Key pointsThe main adaptation to long-term physical activity is lowering of resting heart rate, even after controlling for genetic liability.VO2peak is increased in the active co-twins compared with their inactive co-twins and accordingly, also submaximal heart rates during the clinical exercise test are lower in physically active co-twins.There is a tendency for increased LVM per body weight and heightened T wave amplitude in the active co-twins. PMID:24149594

Mutikainen, Sara; Perhonen, Merja; Alén, Markku; Leskinen, Tuija; Karjalainen, Jouko; Rantanen, Taina; Kaprio, Jaakko; Kujala, Urho M

2009-01-01

108

Effects of Long-Term Physical Activity on Cardiac Structure and Function: A Twin Study  

PubMed Central

Previous studies have shown that athletic training or other physical activity causes structural and functional adaptations in the heart, but less is known how long-term physical activity affects heart when genetic liability and childhood environment are taken into account. The aim of this study was to investigate the effects of long-term physical activity vs. inactivity on cardiac structure and function in twin pairs discordant for physical activity for 32 years. Twelve same-sex twin pairs (five monozygotic and seven dizygotic, 50-67 years) were studied as a part of the TWINACTIVE study. Discordance in physical activity was initially determined in 1975 and it remained significant throughout the follow-up. At the end of the follow-up in 2007, resting echocardiographic and electrocardiographic measurements were performed. During the follow-up period, the active co-twins were on average 8.2 (SD 4.0) MET hours/day more active than their inactive co-twins (p < 0.001). At the end of the follow-up, resting heart rate was lower in the active than inactive co-twins [59 (SD 5) vs. 68 (SD 10) bpm, p=0.03]. The heart rate-corrected QT interval was similar between the co-twins. Also, there was a tendency for left ventricular mass per body weight to be greater and T wave amplitude in lead II to be higher in the active co-twins (18% and 15%, respectively, p=0.08 for both). Similar trends were found for both monozygotic and dizygotic twin pairs. In conclusion, the main adaptation to long- term physical activity is lowered resting heart rate, even after partially or fully controlling for genetic liability and childhood environment. Key points The main adaptation to long-term physical activity is lowering of resting heart rate, even after controlling for genetic liability. VO2peak is increased in the active co-twins compared with their inactive co-twins and accordingly, also submaximal heart rates during the clinical exercise test are lower in physically active co-twins. There is a tendency for increased LVM per body weight and heightened T wave amplitude in the active co-twins.

Mutikainen, Sara; Perhonen, Merja; Alen, Markku; Leskinen, Tuija; Karjalainen, Jouko; Rantanen, Taina; Kaprio, Jaakko; Kujala, Urho M.

2009-01-01

109

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

National Technical Information Service (NTIS)

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 ...

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

1997-01-01

110

Inhibition of activity-dependent arc protein expression in the rat hippocampus impairs the maintenance of long-term potentiation and the consolidation of long-term memory.  

PubMed

It is widely believed that the brain processes information and stores memories by modifying and stabilizing synaptic connections between neurons. In experimental models of synaptic plasticity, such as long-term potentiation (LTP), the stabilization of changes in synaptic strength requires rapid de novo RNA and protein synthesis. Candidate genes, which could underlie activity-dependent plasticity, have been identified on the basis of their rapid induction in brain neurons. Immediate-early genes (IEGs) are induced in hippocampal neurons by high-frequency electrical stimulation that induces LTP and by behavioral training that results in long-term memory (LTM) formation. Here, we investigated the role of the IEG Arc (also termed Arg3.1) in hippocampal plasticity. Arc protein is known to be enriched in dendrites of hippocampal neurons where it associates with cytoskeletal proteins (Lyford et al., 1995). Arc is also notable in that its mRNA and protein accumulate in dendrites at sites of recent synaptic activity (Steward et al., 1998). We used intrahippocampal infusions of antisense oligodeoxynucleotides to inhibit Arc protein expression and examined the effect of this treatment on both LTP and spatial learning. Our studies show that disruption of Arc protein expression impairs the maintenance phase of LTP without affecting its induction and impairs consolidation of LTM for spatial water task training without affecting task acquisition or short-term memory. Thus, Arc appears to play a fundamental role in the stabilization of activity-dependent hippocampal plasticity. PMID:10818134

Guzowski, J F; Lyford, G L; Stevenson, G D; Houston, F P; McGaugh, J L; Worley, P F; Barnes, C A

2000-06-01

111

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

112

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

113

Solar cycle 24: Implications for energetic particles and long-term space climate change  

NASA Astrophysics Data System (ADS)

The recent solar minimum was the longest and deepest of the space age, with the lowest average sunspot numbers for nearly a century. The Sun appears to be exiting a grand solar maximum (GSM) of activity which has persisted throughout the space age, and is headed into a significantly quieter period. Indeed, initial observations of solar cycle 24 (SC24) continue to show a relatively low heliospheric magnetic field strength and sunspot number (R), despite the average latitude of sunspots and the inclination of the heliospheric current sheet showing the rise to solar maximum is well underway. We extrapolate the available SC24 observations forward in time by assuming R will continue to follow a similar form to previous cycles, despite the end of the GSM, and predict a very weak cycle 24, with R peaking at ˜65-75 around the middle/end of 2012. Similarly, we estimate the heliospheric magnetic field strength will peak around 6nT. We estimate that average galactic cosmic ray fluxes above 1GV rigidity will be ˜10% higher in SC24 than SC23 and that the probability of a large SEP event during this cycle is 0.8, compared to 0.5 for SC23. Comparison of the SC24 R estimates with previous ends of GSMs inferred from 9300 years of cosmogenic isotope data places the current evolution of the Sun and heliosphere in the lowest 5% of cases, suggesting Maunder Minimum conditions are likely within the next 40 years.

Owens, M. J.; Lockwood, M.; Barnard, L.; Davis, C. J.

2011-10-01

114

Very long-term X-ray variations in LMXBs: solar cycle-like variations in the donor?  

NASA Astrophysics Data System (ADS)

Long-term monitoring of Low Mass X-ray Binaries (LMXBs) by the All Sky Monitor on board the Rossi X-ray Timing Explorer now covers ~13yr and shows that certain LMXB types display very long-term (approximately several to tens of years) quasi-periodic modulations. These time-scales are much longer than any `super-orbital' periods reported hitherto and likely have a different origin. We suggest here that they are due to long-term variations in the mass-transfer rate from the donor, which are a consequence of solar-like magnetic cycles that lead to Porb changes (as proposed by Richman, Applegate & Patterson for similar long-term variations in cataclysmic variables). Atoll sources display much larger amplitude modulations than Z sources over these time-scales, presumably because Z sources are Eddington limited and hence unable to respond as readily as Atoll sources to fluctuations in the mass-transfer rate from the donor.

Kotze, M. M.; Charles, P. A.

2010-02-01

115

Telemetry facilitates long-term recording of gastrointestinal myoelectrical activity in pigs.  

PubMed

A method of telemetric measurement of antroduodenal myoelectrical activity (EMG) in freely moving pigs has been developed. Silver bipolar electrodes were sutured on the antrum and duodenum and connected to a telemetry transmitter implanted extraperitoneally between the abdominal muscles. The EMG signals were collected by a receiver, filtered, amplified and archived by a computer. The telemetric EMG signal did not differ from that obtained with a conventional wire method. Substantial differences between day and night migrating myoelectric complex (MMC) patterns were found. The advantages of telemetric EMG recording make it a useful tool for long-term recording of antroduodenal EMG. PMID:10751521

Gacsalyi, U; Zabielski, R; Pierzynowski, S G

2000-03-01

116

The impact of materials selection on long-term activation in fusion power plants  

NASA Astrophysics Data System (ADS)

Neutron-induced transmutation of materials in a D-T fusion power plant will give rise to the potential for long-term activation. To ensure that the attractive safety and environmental characteristics of fusion power are not degraded, careful design choices are necessary. An aim of optimising power plant design must be to minimise both the level of activation and the total volume of active material that might ultimately be categorised as waste requiring disposal. Materials selection is central to this optimisation. In this paper we assess the influence of materials choices for a power plant on the waste volume and the potential to clear (i.e. remove from regulatory control) and recycle material. Although the use of low activation materials in regions of high neutron flux is an important part of the strategy to minimise the level of activation, different choices may result from a strategy aimed at minimising the volume of active waste.

Taylor, N. P.; Forty, C. B. A.; Petti, D. A.; McCarthy, K. A.

2000-12-01

117

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

118

Methodology for Using Long-Term Accelerometry Monitoring to Describe Daily Activity Patterns in COPD  

PubMed Central

We sought to develop procedures for computerized analysis of long-term, high-resolution activity monitoring data that allow accurate assessment of the time course of activity levels suitable for use in chronic obstructive pulmonary disease (COPD) patients. Twenty-two COPD patients utilizing long-term oxygen recruited from 5 sites of the COPD Clinical Research Network wore a triaxial accelerometer (RT3, Stayhealthy, Monrovia, CA) during waking hours over a14 day period. Computerized algorithms were composed allowing minute-by-minute activity data to be analyzed to determine, for each minute, whether the monitor was being worn. Temporal alignment allowed determination of average time course of activity level, expressed as average vector magnitude units (VMU, the vectorial sum of activity counts in three orthogonal directions) per minute, for each hour of the day. Mid-day activity was quantified as average VMU/minute between 10AM and 4PM for minutes the monitor was worn. Over the 14 day monitoring period, subjects wore the monitor an average of 11.4±3.0 hours·day?1. During midday hours, subjects wore the monitor 76.3% of the time and generated an average activity level of 112±55 VMU·min?1. Increase in precision of activity estimates with longer monitoring periods was demonstrated. This analysis scheme allows a detailed temporal pattern of activity to be defined from triaxial accelerometer recordings and has the potential to facilitate comparisons among subjects and between subject groups. This trial is registered at ClinicalTrials.gov (NCT00325754).

Hecht, Ariel; Ma, Shuyi; Porszasz, Janos; Casaburi, Richard

2010-01-01

119

Social Cognitive Influences on Physical Activity Participation in Long-Term Breast Cancer Survivors  

PubMed Central

Objective Although physical activity is beneficial for breast cancer survivors, the majority do not meet physical activity public health recommendations. The purpose of this study was to test a social cognitive theory (SCT) model of physical activity behavior in a sample of long-term breast cancer survivors using both self-report and objective measures of physical activity. Methods Participants (N= 1527) completed measures of physical activity, self-efficacy, goals, outcome expectations, fatigue, and social support at baseline and 6-month follow-up. A subsample (n= 370) was randomly selected to wear an accelerometer. It was hypothesized that self-efficacy directly and indirectly influences physical activity through goals, social support, fatigue, and outcome expectations. Relationships were examined using panel analysis within a covariance modeling framework. Results The hypothesized model provided a good model-data fit (?2 = 1168.73, df= 271, p= <.001; CFI=.96; SRMR = 0.04) in the full sample when controlling for covariates. At baseline, self-efficacy directly and indirectly, via goals, outcome expectations and social support, influenced physical activity. These relationships were also supported across time. Additionally, the hypothesized model was supported in the subsample with accelerometer data (?2 = 656.88, df = 330, p = 0.00, CFI = 0.95,SRMR = 0.05). Conclusions This study validates a social cognitive model for understanding physical activity behavior in long-term breast cancer survivors. Future studies should be designed to replicate this model in other breast cancer survivor populations and the findings should be applied to the development of future physical activity programs and studies for this population.

Phillips, Siobhan M.; McAuley, Edward

2014-01-01

120

Involvement of microglia activation in the lead induced long-term potentiation impairment.  

PubMed

Exposure of Lead (Pb), a known neurotoxicant, can impair spatial learning and memory probably via impairing the hippocampal long-term potentiation (LTP) as well as hippocampal neuronal injury. Activation of hippocampal microglia also impairs spatial learning and memory. Thus, we raised the hypothesis that activation of microglia is involved in the Pb exposure induced hippocampal LTP impairment and neuronal injury. To test this hypothesis and clarify its underlying mechanisms, we investigated the Pb-exposure on the microglia activation, cytokine release, hippocampal LTP level as well as neuronal injury in in vivo or in vitro model. The changes of these parameters were also observed after pretreatment with minocycline, a microglia activation inhibitor. Long-term low dose Pb exposure (100 ppm for 8 weeks) caused significant reduction of LTP in acute slice preparations, meanwhile, such treatment also significantly increased hippocampal microglia activation as well as neuronal injury. In vitro Pb-exposure also induced significantly increase of microglia activation, up-regulate the release of cytokines including tumor necrosis factor-alpha (TNF-?), interleukin-1? (IL-1?) and inducible nitric oxide synthase (iNOS) in microglia culture alone as well as neuronal injury in the co-culture with hippocampal neurons. Inhibiting the microglia activation with minocycline significantly reversed the above-mentioned Pb-exposure induced changes. Our results showed that Pb can cause microglia activation, which can up-regulate the level of IL-1?, TNF-? and iNOS, these proinflammatory factors may cause hippocampal neuronal injury as well as LTP deficits. PMID:22952811

Liu, Ming-Chao; Liu, Xin-Qin; Wang, Wen; Shen, Xue-Feng; Che, Hong-Lei; Guo, Yan-Yan; Zhao, Ming-Gao; Chen, Jing-Yuan; Luo, Wen-Jing

2012-01-01

121

Constitutive ?-opioid receptor activity leads to long-term endogenous analgesia and dependence.  

PubMed

Opioid receptor antagonists increase hyperalgesia in humans and animals, which indicates that endogenous activation of opioid receptors provides relief from acute pain; however, the mechanisms of long-term opioid inhibition of pathological pain have remained elusive. We found that tissue injury produced ?-opioid receptor (MOR) constitutive activity (MOR(CA)) that repressed spinal nociceptive signaling for months. Pharmacological blockade during the posthyperalgesia state with MOR inverse agonists reinstated central pain sensitization and precipitated hallmarks of opioid withdrawal (including adenosine 3',5'-monophosphate overshoot and hyperalgesia) that required N-methyl-D-aspartate receptor activation of adenylyl cyclase type 1. Thus, MOR(CA) initiates both analgesic signaling and a compensatory opponent process that generates endogenous opioid dependence. Tonic MOR(CA) suppression of withdrawal hyperalgesia may prevent the transition from acute to chronic pain. PMID:24052307

Corder, G; Doolen, S; Donahue, R R; Winter, M K; Jutras, B L; He, Y; Hu, X; Wieskopf, J S; Mogil, J S; Storm, D R; Wang, Z J; McCarson, K E; Taylor, B K

2013-09-20

122

Repeated solarization and long-term effects on soil microbiological parameters and agronomic traits  

Microsoft Academic Search

Innovative methods less invasive for man and environment are needed to solve the problem of weeds, pests and diseases in cropping systems. Soil solarization is one practice that involves passively heating soil covered by a thin clear plastic film for several weeks during the periods of high solar radiation before the crop is planted. Soil solarization treatments were repeated to

Antonio Scopa; Vincenzo Candido; Stefano Dumontet; Vincenzo Pasquale; Vito Miccolis

2009-01-01

123

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

Microsoft Academic Search

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

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

2010-01-01

124

Long Term Solar Heat Storage through Water Tanks for the Heating of Housing.  

National Technical Information Service (NTIS)

The report concerning a research on solar plants fitted with buried water tanks for the interseasonal storage of solar heat. Computer codes for the design of such plants are described, as well as the design and the construction of a prototype solar plant ...

M. Cucumo, V. Marinelli, V. Marinelli, G. Oliveti, A. Sabato

1985-01-01

125

Developing a Long-term, High-resolution, Continental-scale, Spatially Distributed Time-series of Topographically Corrected Solar Radiation  

Microsoft Academic Search

Our aim is to develop a long-term, high resolution net radiation data set that accounts for the effects of local topography that confound simpler analyses of the shortwave radiative balance in rugged terrain; such a dataset may then be used in direct observations of the effects of long-term change and variability in the solar radiation input to the land surface-

Michael T. Hobbins; Jorge A. Ramírez; Thomas C. Brown

2004-01-01

126

Solar irradiance at the Earth's surface: long-term behavior observed at the South Pole  

Microsoft Academic Search

This research examines a 17-year database of UV-A (320-400 nm) and visible (400-600 nm) solar irradiance obtained by a scanning spectroradiometer located at the South Pole. The goal is to define the variability in solar irradiance reaching the polar surface, with emphasis on the influence of cloudiness and on identifying systematic trends and possible links to the solar cycle. To

J. E. Frederick; A. L. Hodge

2010-01-01

127

Solar irradiance at the earth's surface: long-term behavior observed at the South Pole  

Microsoft Academic Search

This research examines a 17-year database of UV-A (320-400 nm) and visible (400-600 nm) solar irradiance obtained by a scanning spectroradiometer located at the South Pole. The goal is to define the variability in solar irradiance reaching the polar surface, with emphasis on the influence of cloudiness and on identifying systematic trends and possible links to the solar cycle. To

J. E. Frederick; A. L. Hodge

2011-01-01

128

Long-term effects of silver nanoparticles on reproductive activity of rabbit buck.  

PubMed

Using the rabbit as an animal model, this study evaluated the long-term effect of silver nanoparticles (NPs) administered intravenously (0.6 mg/kg bw) on reproductive activity and sperm quality. Semen analysis was performed by optical microscopy and sperm motility evaluation by computer assisted sperm analyzer (CASA). Mitochondria oxygen consumption, light and transmission electron microscopy of rabbit testis and ejaculated sperm were also carried out. Throughout the experiment NP-treated rabbits showed higher seminal reactive oxygen species (ROS), less motile sperm, and lower curvilinear velocity and oxygen consumption than control animals. In contrast, libido, serum testosterone, sperm concentration, and semen volume were hardly affected by NPs. Transmission electron microscopy analysis did not show any evident morphological damage in testes; however, Ag NPs are visible in spermatids and ejaculated sperm. These preliminary results show that Ag NPs can reach the testes, compromising sperm motility, sperm speed, and acrosome and mitochondria shape and function. PMID:24547726

Castellini, Cesare; Ruggeri, Silvia; Mattioli, Simona; Bernardini, Giovanni; Macchioni, Lara; Moretti, Elena; Collodel, Giulia

2014-06-01

129

Adrenergic ?1 receptor activation is sufficient, but not necessary for phrenic long-term facilitation.  

PubMed

Acute intermittent hypoxia (AIH; three 5-min hypoxic episodes) causes a form of phrenic motor facilitation (pMF) known as phrenic long-term facilitation (pLTF); pLTF is initiated by spinal activation of Gq protein-coupled 5-HT2 receptors. Because ?1 adrenergic receptors are expressed in the phrenic motor nucleus and are also Gq protein-coupled, we hypothesized that ?1 receptors are sufficient, but not necessary for AIH-induced pLTF. In anesthetized, paralyzed, and ventilated rats, episodic spinal application of the ?1 receptor agonist phenylephrine (PE) elicited dose-dependent pMF (10 and 100 ?M, P < 0.05; but not 1 ?M). PE-induced pMF was blocked by the ?1 receptor antagonist prazosin (1 mM; -20 ± 20% at 60 min, -5 ± 21% at 90 min; n = 6). Although ?1 receptor activation is sufficient to induce pMF, it was not necessary for AIH-induced pLTF because intrathecal prazosin (1 mM) did not alter AIH-induced pLTF (56 ± 9% at 60 min, 78 ± 12% at 90 min; n = 9). Intravenous (iv) prazosin (150 ?g/kg) appeared to reduce pLTF (21 ± 9% at 60 min, 26 ± 8% at 90 min), but this effect was not significant. Hypoglossal long-term facilitation was unaffected by intrathecal prazosin, but was blocked by iv prazosin (-4 ± 14% at 60 min, -13 ± 18% at 90 min), suggesting different LTF mechanisms in different motor neuron pools. In conclusion, Gq protein-coupled ?1 adrenergic receptors evoke pMF, but they are not necessary for AIH-induced pLTF. PMID:24526581

Huxtable, A G; MacFarlane, P M; Vinit, S; Nichols, N L; Dale, E A; Mitchell, G S

2014-06-01

130

Long-term radiation effects on GaAs solar cell characteristics  

Microsoft Academic Search

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

J. H. Heinbockel; M. J. Doviak

1978-01-01

131

Sunspot activity and the long-term variation of the Sun's open magnetic flux  

NASA Astrophysics Data System (ADS)

The interplanetary magnetic field (IMF) originates in open magnetic regions of the Sun (coronal holes), which in turn form mainly through the emergence and dispersal of active region fields. The radial IMF strength is proportional to the total open flux ?open, which can be estimated from source surface extrapolations of the measured photospheric field, after correction for magnetograph saturation effects. We derive the long-term variation of ?open during 1971-2000 and discuss its relation to sunspot activity. The average value of ?open was ˜20-30% higher during 1976-1996 than during 1971-1976 and 1996-2000, with major peaks occurring in 1982 and 1991. Near sunspot minimum, most of the open flux resides in the large polar coronal holes, whereas at sunspot maximum it is rooted in relatively small, low-latitude holes located near active regions and characterized by strong footpoint fields; since the decrease in the total area occupied by holes is offset by the increase in their average field strengths, ?open remains roughly constant between activity minimum and maximum, unlike the total photospheric flux ?tot. The long-term variation of ?open approximately follows that of the Sun's total dipole strength, with a contribution from the magnetic quadrupole around sunspot maximum. Global fluctuations in sunspot activity lead to increases in the equatorial dipole strength and hence to enhancements in ?open and the IMF strength lasting typically ˜1 year. We employ simulations to clarify the role of active region emergence and photospheric transport processes in the evolution of the open flux. Representing the initial field configuration by one or more bipolar magnetic regions (BMRs), we calculate its subsequent evolution under the influence of differential rotation, supergranular convection, and a poleward bulk flow. The initial value of ?open is determined largely by the equatorial dipole strength, which in turn depends on the longitudinal phase relations between the BMRs. As the surface flow carries the BMR flux to higher latitudes, the equatorial dipole is annihilated on a timescale of ˜1 year by the combined effect of rotational shearing and turbulent diffusion. The remaining flux becomes concentrated around the poles, and ?open approaches a limiting value that depends on the axisymmetric dipole strengths of the original BMRs. The polar coronal holes thus represent the long-lived, axisymmetric remnant of the active regions that emerged earlier in the cycle.

Wang, Y.-M.; Sheeley, N. R.

2002-10-01

132

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

133

Long-term effect of temperature on N2O emission from the denitrifying activated sludge.  

PubMed

The long-term effect of various temperature (4°C, 12°C, 20°C, 25°C and 34°C) on nitrous oxide (N2O) emission from lab-scale denitrifying activated sludge was studied in terms of activation energy, abundance of functional gene nosZ and its transcription. Results showed that temperature had a positive effect on N2O emissions as well as the maximum biomass-specific reduction rates of N2O and NO3(-), ranging from 0.006% to 0.681% of (N2O + N2), 17.3-116.2 and 5.2-66.2 mg N g(-1) VSS h(-1), respectively. The activation energies (Ea) for N2O and NO3(-) reduction of 44.1 kJ mol(-1) and 54.9 kJ mol(-1), shed light on differences in denitrifying rate variation. The maximum NO3(-) reduction rates were more sensitive to temperature variation than the corresponding N2O reduction rates under long-term acclimation. As a result, the ratio between N2O and NO3(-) reduction rates declined to 1.87 at 34°C from 3.31 at 4°C, suggesting great potential capacity for N2O losses at high temperature. The copy numbers of denitrifiers as nosZ gene (×10(8) copies mL(-1)) and total bacteria as 16S rRNA gene (×10(10) copies mL(-1)) did not show obvious relationship with temperature, having relative abundance of 0.42% on average. The transcriptional regulation of nosZ gene, in the range of 10(8)-10(5) copies mL(-1), was affected by reductase activity, substrate concentration as well as its duration. The active nosZ gene expression was accompanied with low reductase capacity, high dissolved N2O and the duration of N2O accumulation. These results provide insights into activation energy and gene expression responsible for N2O emission. PMID:24480748

Wang, Xiaojun; Yang, Xiaoru; Zhang, Zhaoji; Ye, Xin; Kao, Chih Ming; Chen, Shaohua

2014-03-01

134

Combinatorial study of the long-term stability of organic thin-film solar cells  

Microsoft Academic Search

We present a setup that allows us to combinatorially study organic multilayer devices for durability and degradation mechanisms. Arrays of 8 x8 thin-film organic devices are prepared by vacuum deposition and investigated under vacuum conditions. Measurements of nine types of organic solar cells are presented. Continuous solar-like illumination at 80 mW\\/cm2 and a temperature of 80 degC provide realistic testing

Helmut Hansel; Heiko Zettl; Georg Krausch; Christoph Schmitz; Roman Kisselev; Mukundan Thelakkat; Hans-Werner Schmidt

2002-01-01

135

Long-term variation in distribution of solar wind density fluctuations for 1997-2009  

NASA Astrophysics Data System (ADS)

Interplanetary scintillation (IPS) observations made with the 327-MHz multi-station system of the Solar-Terrestrial Environment Laboratory (STEL) are analyzed to investigate distribution of solar wind density fluctuations (Delta Ne) and its evolution during 1997-2009. The computer assisted tomography (CAT) method is used in the present study to deconvolve line-of-sight integration of solar wind speed and g-value data obtained from IPS observations (Asai et al., 1998). The results show that the high-(low-) latitude region is dominated by small (large) Delta Ne plasma, which corresponds to the fast (slow) solar wind. The solar wind speed data show a clear change associated with the solar cycle, and this is in good agreement with our earlier study (Tokumaru et al., 2010). In contrast, the Delta Ne data don't show such a solar cycle change, and they shows a gradual increase in fractional area of small Delta Ne region throughout the period. This trend is observed for all latitudes, and is distinct after 2005 for low latitudes. It is found that all IPS data obtained here except for those in 2000 are generally consistent with the empirical relation; Delta Ne ~ V-0.5, (where V is the solar wind speed) reported by Asai et al.(1998). The important point to note is that a marked reduction in Delta Ne occurs in 2009 for the low speed wind, V <350 km/s. Since number of IPS data for this speed range may be insufficient to conclude, we need to confirm this reduction in Delta Ne from further observations.

Tokumaru, M.; Kojima, M.; Fujiki, K.

2011-12-01

136

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.

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

2013-01-01

137

Outcome of long term active surveillance for estrogen receptor-positive ductal carcinoma in situ  

PubMed Central

Introduction An option for active surveillance is not currently offered to patients with ductal carcinoma in situ (DCIS); however a small number of women decline standard surgical treatment for noninvasive cancer. The purpose of this study was to assess outcomes in a cohort of 14 well-informed women who elected non-surgical active surveillance with endocrine treatment alone for estrogen receptor-positive DCIS. Methods Retrospective review of 14 women, 12 of whom were enrolled in an IRB-approved single-arm study of 3 months of neoadjuvant endocrine therapy prior to definitive surgical management. The patients in this report withdrew from the parent study opting instead for active surveillance with endocrine treatment and imaging. Results 8 women had surgery at a median follow up of 28.3 months (range 10.1–70 months), 5 had stage I IDC at surgical excision, and 3 had DCIS alone. 6 women remain on surveillance without evidence of invasive disease for a median of 31.8 months (range 11.8–80.8 months). Conclusion Long-term active surveillance for DCIS is feasible in a well-informed patient population, but is associated with risk of invasive cancer at surgical excision.

Meyerson, Anna F.; Lessing, Juan N.; Itakura, Kaoru; Hylton, Nola M.; Wolverton, Dulcy E.; Joe, Bonnie N.; Esserman, Laura J.; Hwang, E. Shelley

2014-01-01

138

Predicting the ageing and the long-term durability of organic polymer solar cells  

NASA Astrophysics Data System (ADS)

Organic solar cells based on conductive polymers exhibit a unique combination of properties which include low cost, flexibility and large surface processability. Organic photovoltaic could then prevail for some applications alongside silicon, such as nomad or indoor. To achieve this objective, the sustainability of the initial properties in conditions of use of the cell is required, since it could be a lock to the emergence of these devices in the market. The polymers used in solar cells are indeed known to exhibit low resistance to environmental constraints, in particular to the combined action of sunlight, oxygen and water. We present recent results on both the accelerated artificial and the natural outdoors ageing of MDMO-PPV (Poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-Phenylenevinylene) and P3HT/PCBM blends poly(3-hexylthiophene) (P3HT) (methano-fullerene[6,6]-phenyl C61-butyric acid methyl ester) ([60] PCBM). The influence of various parameters such as the temperature and the presence of oxygen were studied. The modifications of the chemical structure of both the components of the blend were monitored by spectroscopic analysis (infrared, UV-visible), the morphology of the blends was analysed by AFM and XRD and the photovoltaic performances all along the exposure were recorded. Two important results have been pointed out: on one hand, the Achilles heel of the chemical structure of MDMO-PPV and P3HT under the impact of light has been evidenced. On the other hand, it has been shown that P3HT:PCBM blends are much more stable than MDMO:PCBM blends whatever the conditions of ageing are. Results show that a convenient encapsulation can ensure a promising lifetime of P3HT/PCBM blends in real conditions of use. This work also focuses on this last point and proposes to study and try to understand the behavior of the materials used in the active layer when submitted to photoaging and thermal aging in the absence of oxygen. To fulfil very good encapsulation, glass substrates can be used. However, as a result, organic devices lose some of their attractive properties, such as flexibility. Organic PV cells finally need a complex layer stack as a permeation barrier to be protected from water and oxygen of the environment. Multilayer barrier coatings are required: on the one hand, there are inorganic materials applied as thin films. Those films show a preferential permeation at defects. For the most part, these inorganic materials are then used in combination with a polymeric substrate. Polymers can be considered as being homogeneous with regard to the usually utilized substrate or film thicknesses. Their barrier properties can be reinforced by nanoclays. The impermeable clay layers force a tortuous pathway for a permeant transversing the nanocomposite. It is reported that gas permeability through polymer films can be reduced by 50-500 times even with small loadings of nanoclays.

Gardette, Jean-Luc; Rivaton, Agnès; Thérias, Sandrine; Chambon, Sylvain; Manceau, Matthieu; Gaume, Julien

2010-06-01

139

Solar cell packaged by a microlens array and its long-term optical efficiency enhancement  

NASA Astrophysics Data System (ADS)

A technique of mounting a microlens array (MLA) on a solar cell as an encapsulation layer is presented. The uniform cylinder-shaped MLA was fabricated through simple and cost-effective micromachining processes. The efficiency of the triple-junction InGaP/GaAs/Ge solar cell was considerably enhanced by replacing a bare glass cover with the developed MLA as a surface protection layer. This is attributed to efficient conveyance of the refractive light into bare photoactive regions of the solar cell to avoid the gridlines. Under the optimal mounting condition with an optimal height of optical spacer, the MLA effect was maximized resulting in a 16.8% increase in power conversion efficiency (PCE) than that of the control device. The efficiency of the MLA-packaged solar cell remained for a long time without degradation. The MLA can therefore replace a conventional glass (or film) as a means of encapsulation layer to enhance photovoltaic performances of GaAs-based solar cells.

Nam, Minwoo; Kim, Kangho; Lee, Jaejin; Yang, Sang Sik; Lee, Kee-Keun

2013-03-01

140

Long-Term Outcome after Lithium Augmentation in Unipolar Depression: Focus on HPA System Activity  

Microsoft Academic Search

Background: Lithium augmentation is a first-line strategy for depressed patients resistant to antidepressive therapy, but little is known about patients’ subsequent long-term course or outcome predictors. We investigated long-term outcomes of unipolar depressed patients who had participated in a study on the effects of lithium augmentation on the hypothalamic-pituitary-adrenocortical system using the combined dexamethasone\\/corticotrophin-releasing hormone (DEX\\/CRH) test. Methods: Twelve to

Mazda Adli; Tom Bschor; Michael Bauer; Claudia Lucka; Ute Lewitzka; Marcus Ising; Manfred Uhr; Bruno Mueller-Oerlinghausen; Christopher Baethge

2009-01-01

141

Ventricular activity morphological characterization: ectopic beats removal in long term atrial fibrillation recordings.  

PubMed

Ectopic beats are early heart beats remarkably different to the normal beat morphology that provoke serious disturbances in electrocardiographic analysis. These beats are very common in atrial fibrillation (AF), causing important residua when ventricular activity has to be removed for atrial activity (AA) analysis. In this work, a method is proposed to cancel out ectopics by discriminating between normal and abnormal beats, with an accuracy higher than 99%, through QRS morphological delineation and characterization. The most similar ectopics to the one under cancellation are clustered to provide a very precise cancellation template. Simulated and real AF recordings were used to validate the method. A new index, able to estimate the presence of ventricular residue after ectopics cancellation, was defined. Results by using the 2, 4, 6, …, 30 most similar ectopics to the one under study yielded optimal cancellation for templates composed of 10 beats. Furthermore, these beats were very likely located close to the ectopic under cancellation, which could facilitate the algorithm implementation. As conclusion, the proposed method is an effective way to remove ectopics from long term AF recordings and get them ready for the application of any QRST cancellation technique able to extract the AA in optimal conditions. Moreover, it could also detect, characterize and remove ectopics in any other type of non-AF recordings. PMID:23228563

Martínez, Arturo; Alcaraz, Raúl; Rieta, José J

2013-03-01

142

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

143

An hybrid neuro-wavelet approach for long-term prediction of solar wind  

NASA Astrophysics Data System (ADS)

Nowadays the interest for space weather and solar wind forecasting is increasing to become a main relevance problem especially for telecommunication industry, military, and for scientific research. At present the goal for weather forecasting reach the ultimate high ground of the cosmos where the environment can affect the technological instrumentation. Some interests then rise about the correct prediction of space events, like ionized turbulence in the ionosphere or impacts from the energetic particles in the Van Allen belts, then of the intensity and features of the solar wind and magnetospheric response. The problem of data prediction can be faced using hybrid computation methods so as wavelet decomposition and recurrent neural networks (RNNs). Wavelet analysis was used in order to reduce the data redundancies so obtaining representation which can express their intrinsic structure. The main advantage of the wavelet use is the ability to pack the energy of a signal, and in turn the relevant carried informations, in few significant uncoupled coefficients. Neural networks (NNs) are a promising technique to exploit the complexity of non-linear data correlation. To obtain a correct prediction of solar wind an RNN was designed starting on the data series. As reported in literature, because of the temporal memory of the data an Adaptative Amplitude Real Time Recurrent Learning algorithm was used for a full connected RNN with temporal delays. The inputs for the RNN were given by the set of coefficients coming from the biorthogonal wavelet decomposition of the solar wind velocity time series. The experimental data were collected during the NASA mission WIND. It is a spin stabilized spacecraft launched in 1994 in a halo orbit around the L1 point. The data are provided by the SWE, a subsystem of the main craft designed to measure the flux of thermal protons and positive ions.

Napoli, Christian; Bonanno, Francesco; Capizzi, Giacomo

2011-06-01

144

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

PubMed Central

Extracellular cesium causes synchronous, interictal-like bursting 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) exposures, a late depolarizing response was observed; this effect was not associated with changes in cell membrane conductance. Recordings from interneurons revealed that Ih is expressed in a sub-population of cells and that cesium effects on interneurons expressing Ih are comparable to those observed in pyramidal cells. Consistent with this effect, cesium decreased the early component of the IPSP recorded in pyramidal cells. Interneurons lacking Ih were not affected by cesium but developed a depolarizing response when drug applications were paired to orthodromic stimulation. We concluded that cesium actions on LTD and cesium-induced epileptiform activity were not attributable exclusively to its direct effects on neurons. Recordings from hippocampal slice astrocytes revealed that cesium interfered with glial electrical responses during LTD induction. Cesium blocked glial inwardly rectifying potassium channels and increased the amplitude and duration of stimulation-evoked [K+]out increases. Thus, the effects of cesium on CA1 synchronization and synaptic plasticity appear to be mediated predominantly by blockade of glial voltage-dependent potassium uptake.

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

2014-01-01

145

Novel functional Renilla luciferase mutant provides long-term serum stability and high luminescence activity.  

PubMed

Fluorescent and luminescent chemical probes are essential in recent medical diagnostics. However, the use of these probes in vivo has raised concerns due to their low sensitivity, background signal interference, and non-biocompatibility. Therefore, biological chromophores have received much attention as new alternatives. In particular, luciferase, a class of oxidative enzyme with bioluminescence, has emerged as a promising fluorophore due to its improved biocompatibility. However, the enzyme usually possesses weaker luminescence and stability relative to its chemically-based competitors. Here, we report a novel functional mutant luciferase with both enhanced luminescence and long-term serum stability. For the preparation of the modified Renilla luciferase, a new bacterial subcloning design was established. The luciferase coding DNA sequence was redesigned so that mutant luciferase could be easily expressed in an Escherichia coli system. The mutant Renilla luciferase, which we called "m-Rluc," demonstrated characteristic enzymatic functions and showed a 5.6-fold increase in luminescence activity. In addition, the enzyme's physiological stability remained >80% for more than 5days, in contrast to conventional luciferase, termed "hrluc," which disappeared within a few hours. We suggest that this novel biological luciferase probe may be a great tool for both in vitro and in vivo medical diagnostics. PMID:23973867

Song, Woo Chul; Sung, Hye-Jin; Park, Kyung Soo; Choi, Jeong-Woo; Cho, Je-Yeol; Um, Soong Ho

2013-10-01

146

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

147

Solar cycle signature and secular long-term trend in OH airglow temperature observations at South Pole, Antarctica  

NASA Astrophysics Data System (ADS)

We have examined Michelson Interferometer OH airglow temperature data to investigate solar cycle and long-term variations of mesospheric temperatures at South Pole Station (SPS), Antarctica (90°S). The data set used here is continuous (24 hours a day) and taken during 1994-2004 austral winters. We have used a Multiple Linear Regression (MLR) technique to elucidate solar cycle and the trend term in the MI temperature time series data. The 11-year time series of OH rotational temperature shows a strong correlation with F10.7 radio flux (R = 0.60). The amplitude of solar cycle response seen in the mesopause temperature records at South Pole is about 0.04 ± 0.01 K/sfu (Solar Flux Units), however, the trend term is statistically insignificant and is about 0.1 ± 0.2 K/year. Superposed epoch studies have been carried out in order to determine climatological variations in OH temperatures above South Pole derived from 11 years of austral winter observations. The mean amplitude of this variation is about 12.6 K and its maximum occurs near 30 May which is in agreement with the Fabry-Perot Spectrometer (FPS) observations of OH temperatures at SPS (Hernandez, 2003). However, whereas Hernandez (2003) reported 35 K cooling in 2002, MI OH temperatures at SPS do not show any significant deviation from previous years.

Azeem, S. M. I.; Sivjee, G. G.; Won, Y.-I.; Mutiso, Charles

2007-01-01

148

Long-term potentiation activates the GAP-43 promoter: selective participation of hippocampal mossy cells.  

PubMed

Perforant path long-term potentiation (LTP) in intact mouse hippocampal dentate gyrus increased the neuron-specific, growth-associated protein GAP-43 mRNA in hilar cells 3 days after tetanus, but surprisingly not in granule cells, the perforant path target. This increase was positively correlated with level of enhancement and restricted to central hilar cells on the side of stimulation. Blockade of LTP by puffing DL-aminophosphonovalerate (APV), an N-methyl-D-aspartate (NMDA) receptor blocker into the molecular layer, eliminated LTP-induced GAP-43 mRNA elevation in hilar cells. To determine whether the mRNA elevation was mediated by transcription, LTP was studied in transgenic mice bearing a GAP-43 promoter-lacZ reporter gene. Promoter activity as indexed by Transgene expression (PATE) increased as indicated by blue staining of the lacZ gene product, beta-galactosidase. Potentiation induced a blue band bilaterally in the inner molecular layer of the dentate gyrus along the entire septotemporal axis. Because mossy cells are the only neurons in the central hilar zone that project to the inner molecular layer bilaterally along the entire septotemporal axis and LTP-induced activation of PATE in this zone was confined to the side of stimulation, we concluded that mossy cells were unilaterally activated, increasing synthesis of beta-galactosidase, which was transported bilaterally. Neither granule cells nor pyramidal cells demonstrated increased PATE or increased GAP-43 mRNA levels. These results and recent evidence indicating the necessity of hilar neurons for LTP point to previously unheralded mossy cells as potentially critical for perforant path LTP and the GAP-43 in these cells as important for LTP persistence lasting days. PMID:9326669

Namgung, U; Matsuyama, S; Routtenberg, A

1997-10-14

149

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

NASA Astrophysics Data System (ADS)

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 NOx from the polar lower mesosphere and upper stratosphere during the Southern Hemisphere winter period resulted in huge enhancements (>100%) in middle stratospheric NOx (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, NOy (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 NOy resulted in long-lasting ozone decreases (from catalytic NOy destruction of ozone) and ozone increases (from NOy interference in the chlorine and bromine catalytic ozone destruction cycles). These ozone changes resulted in simulated SH polar stratospheric temperature decreases (1-2K) and increases (1-3K).

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

2007-12-01

150

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

151

Stability of EUV multilayers to long-term heating, and to energetic protons and neutrons, for extreme solar missions  

NASA Astrophysics Data System (ADS)

We have systematically investigated the thermal and particle stability of several state-of-the-art EUV multilayer coatings suitable for use in high-performance solar instrumentation. Our research has been motivated principally by the performance requirements for extreme solar missions such as Solar Orbiter, an approved ESA mission with an expected launch date of 2013. The goal of this particular mission is to explore the solar atmosphere with both in situ and remote sensing instrumentation at a close encounter. At perihelion the mission will reach 0.2 A.U. providing a unique viewpoint where the instruments can both 'see' and 'feel' the dynamic atmosphere. But the orbit is technically challenging- no remote sensing instrument has been put in such close proximity to the Sun before. Furthermore, the thermal and particle environment will not only be severe but will suffer huge fluctuations as the elliptical orbit changes from 0.2 A.U. to 1.1 A.U. Several of the remote sensing packages on the strawman payload of the mission contain multilayer coatings, thus the stability of these coatings to the expected thermal and particle environment must be established. In this paper, we investigate the impact on the integrity of several candidate EUV multilayer coatings after long-term thermal annealing, and upon exposure to energetic protons and neutrons. In summary, we find no significant degradation in any of the multilayer samples tested. These results suggest that the multilayers we have studied can be safely used for Solar Orbiter or other extreme solar missions.

Rousseau, A. D.; Windt, D. L.; Winter, B.; Harra, L.; Lamoureux, H.; Eriksson, F.

2005-08-01

152

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

153

Long-term insecticidal activity and physical integrity of Olyset nets in Tafea Province, Vanuatu.  

PubMed

The long-term efficacy of long-lasting insecticidal nets (LLINs) depends on both the physical condition of the net and the residual activity of the insecticide. This study focused on monitoring these parameters in Olyset nets (Sumitomo Chemical Co., Osaka, Japan) (n = 101) that had been used for 1-3 yr in Tafea Province, Vanuatu. Net usage and frequency of washing was ascertained by questionnaire; the nets were assessed with regards to cleanliness and damage owing to holes. Insecticide efficacy was determined with cone bioassays using Anophelesfarauti Laveran. Net usage was high and 86.1% (87 of 101) of villages stated that they used the net every night. Washing of nets was low (11.9%, 12 of 101), and most nets (79.2%, 80 of 101) were considered dirty. Most nets were damaged (73.4% had holes), and 22.8% (23 of 101) had large holes (>200 cm2). The 24-h mortality of An. farauti exposed to nets aged 1-2 yr was 79.4%, while the mortality for nets 3 yr of age was significantly lower at 73.7%. There was no difference in the insecticidal activity of clean compared with dirty nets (mean 24-h mortality: Clean = 76.7%, Dirty = 77.1%). Although the majority of nets had holes, the physical condition of 8.9-22.8% of nets was altered so severely to potentially affect efficacy. Although the 3-yr-old nets would still be providing significant levels of insecticidal and personal protection, consideration should be given to replacing nets >3 yr old. PMID:24605466

Dutta, Shurajit N; Amon, James; Iata, Harry; Cooper, Robert D; Russell, Tanya L

2014-01-01

154

Delayed noradrenergic activation in the dorsal hippocampus promotes the long-term persistence of extinguished fear.  

PubMed

Fear extinction has been extensively studied, but little is known about the molecular processes that underlie the persistence of extinction long-term memory (LTM). We found that microinfusion of norepinephrine (NE) into the CA1 area of the dorsal hippocampus during the early phase (0?h) after extinction enhanced extinction LTM at 2 and 14 days after extinction. Intra-CA1 infusion of NE during the late phase (12?h) after extinction selectively promoted extinction LTM at 14 days after extinction that was blocked by the ?-receptor antagonist propranolol, protein kinase A (PKA) inhibitor Rp-cAMPS, and protein synthesis inhibitors anisomycin and emetine. The phosphorylation levels of PKA, cyclic adenosine monophosphate response element-binding protein (CREB), GluR1, and the membrane GluR1 level were increased by NE during the late phase after extinction that was also blocked by propranolol and Rp-cAMPS. These results suggest that the enhancement of extinction LTM persistence induced by NE requires the activation of the ?-receptor/PKA/CREB signaling pathway and membrane GluR1 trafficking. Moreover, extinction increased the phosphorylation levels of Erk1/2, CREB, and GluR1, and the membrane GluR1 level during the late phase, and anisomycin/emetine alone disrupted the persistence of extinction LTM, indicating that the persistence of extinction LTM requires late-phase protein synthesis in the CA1. Propranolol and Rp-cAMPS did not completely disrupt the persistence of extinction LTM, suggesting that another ?-receptor/PKA-independent mechanism underlies the persistence of extinction LTM. Altogether, our results showed that enhancing hippocampal noradrenergic activity during the late phase after extinction selectively promotes the persistence of extinction LTM. PMID:24553734

Chai, Ning; Liu, Jian-Feng; Xue, Yan-Xue; Yang, Chang; Yan, Wei; Wang, Hui-Min; Luo, Yi-Xiao; Shi, Hai-Shui; Wang, Ji-Shi; Bao, Yan-Ping; Meng, Shi-Qiu; Ding, Zeng-Bo; Wang, Xue-Yi; Lu, Lin

2014-07-01

155

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

156

The Solar Radio Flux on 10.7cm as the best index for Space Weather long-term Prediction  

Microsoft Academic Search

. The Solar Radio Flux on 10.7cm was observed since more than 60 years ago till today at Ottawa, Canada. The daily value of 10.7cm solar flux showed a very good correlation with solar activity than the sunspot number Rz. The space weather is affected by the electromagnetic radiation come from the solar corona (X-ray and gamma-rays). Also, it is

Mosalam Shaltout; Rr. Ramy Mawad; Mohamed Youssef

2008-01-01

157

Correction of Anemia with Continuous Erythropoietin Receptor Activator in Korean Patients on Long-Term Hemodialysis  

PubMed Central

Continuous erythropoietin receptor activator (CERA) is an erythropoietin with a long-half life. This study investigated the efficacy of CERA for correcting anemia in Korean patients on dialysis. Patients (?18 yr) who were not receiving any ESAs for more than 8 weeks were randomly assigned to either intravenous CERA once every 2 weeks (n=39) or epoetin beta thrice-weekly (n=41) during a 24-week correction phase. Hemoglobin (Hb) response was defined as increase of Hb by at least 1 g/dL and Hb?11 g/dL without red blood cell (RBC) transfusion. Median dialysis duration was 1.7 (0.3-20.8) and 1.6 (0.4-13.8) yr in CERA and epoetin beta group, respectively. Hemoglobin response rate of CERA was 79.5% (95% confidence interval [CI], 63.5-90.7). As the lower limit of 95% CI was higher than pre-specified 60% response rate, it can be concluded that CERA corrected anemia (P<0.05). Hb response rate of epoetin beta was 87.8% (95% CI, 73.8-95.9) (P=0.37). Median time to response was 12 weeks in CERA and 10.3 weeks in epoetin beta (P=0.03). It is suggested that once every 2 weeks administration of CERA is effective for correcting anemia in Korean patients on long-term hemodialysis with longer time-to-response than thrice weekly epoetin beta. (ClinicalTrials.gov registry No. NCT00546481)

Oh, Jieun; Joo, Kwon-Wook; Chin, Ho-Jun; Chae, Dong-Wan; Kim, Sung-Gyun; Kim, Soo Jin; Chung, Wookyung; Kim, Sejoong; Huh, Wooseong; Oh, Ha Young; Choi, Bum Soon; Yang, Chul-Woo

2014-01-01

158

LONG-TERM PROFILE VARIABILITY IN ACTIVE GALACTIC NUCLEUS WITH DOUBLE-PEAKED BALMER EMISSION LINES  

SciTech Connect

An increasing number of active galactic nuclei (AGNs) exhibit broad, double-peaked Balmer emission lines, which represent some of the best evidence for the existence of relatively large-scale accretion disks in AGNs. A set of 20 double-peaked emitters have been monitored for nearly a decade in order to observe long-term variations in the profiles of the double-peaked Balmer lines. Variations generally occur on timescales of years, and are attributed to physical changes in the accretion disk. Here we characterize the variability of a subset of seven double-peaked emitters in a model independent way. We find that variability is caused primarily by the presence of one or more discrete 'lumps' of excess emission; over a timescale of a year (and sometimes less) these lumps change in amplitude and shape, but the projected velocity of these lumps changes over much longer timescales (several years). We also find that all of the objects exhibit red peaks that are stronger than the blue peak at some epochs and/or blueshifts in the overall profile, contrary to the expectations for a simple, circular accretion disk model, thus emphasizing the need for asymmetries in the accretion disk. Comparisons with two simple models, an elliptical accretion disk and a circular disk with a spiral arm, are unable to reproduce all aspects of the observed variability, although both account for some of the observed behaviors. Three of the seven objects have robust estimates of the black hole masses. For these objects the observed variability timescale is consistent with the expected precession timescale for a spiral arm, but incompatible with that of an elliptical accretion disk. We suggest that with the simple modification of allowing the spiral arm to be fragmented, many of the observed variability patterns could be reproduced.

Lewis, Karen T. [Department of Physics and Astronomy, Dickinson College, Carlisle, PA 17013 (United States); Eracleous, Michael [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Storchi-Bergmann, Thaisa [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Campus do Vale, Porto Alegre, RS (Brazil)], E-mail: lewiska@dickinson.edu

2010-04-01

159

The prediction of long term monthly mean daily solar gains through vertical single and double clear glazing at sites distributed throughout the UK  

Microsoft Academic Search

A simple approximate method has been developed for estimating long term monthly mean daily solar heat gains per unit area for vertical windows for sites within the UK. The method enables the monthly mean solar gains through vertical single and double glazing of any orientation to be estimated for each of the Department of Energy degree day regions, using a

G. G. Rodgers; J. K. Page; I. D. Colquhoun; J. L. Thompson

1982-01-01

160

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

161

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

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

1993-01-01

162

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

163

The Effect of Psychiatric Rehabilitation on the Activity and Participation Level of Clients with Long-Term Psychiatric Disabilities  

Microsoft Academic Search

During the last decades of the 20th century, many psychiatric hospitals changed the living environments of their clients with long-term psychiatric disabilities. We investigated the effect of this environmental psychiatric rehabilitation and normalization process on the activity and participation level of such clients residing in one Dutch psychiatric hospital. The seven years of panel research demonstrated that more normal living

Tom van Wel; Albert Felling; Jean Persoon

2003-01-01

164

Cortical Activation Patterns during Long-Term Memory Retrieval of Visually or Haptically Encoded Objects and Locations  

ERIC Educational Resources Information Center

The present study used functional magnetic resonance imaging to delineate cortical networks that are activated when objects or spatial locations encoded either visually (visual encoding group, n = 10) or haptically (haptic encoding group, n = 10) had to be retrieved from long-term memory. Participants learned associations between auditorily…

Stock, Oliver; Roder, Brigitte; Burke, Michael; Bien, Siegfried; Rosler, Frank

2009-01-01

165

Response of microbial activity and microbial community composition in soils to long-term arsenic and cadmium exposure  

Microsoft Academic Search

Arsenic (As) and cadmium (Cd) in soils can affect soil microbial function and community composition and, therefore, may have effects on soil ecosystem functioning. The aim of our study was to assess the effects of long-term As and Cd contamination on soil microbial community composition and soil enzyme activities. We analyzed soils that have been contaminated 25 years ago and

Nicola Lorenz; Therese Hintemann; Tanja Kramarewa; Arata Katayama; Tsuyoshi Yasuta; Petra Marschner; Ellen Kandeler

2006-01-01

166

Long-term stability of Angle Class II, Division 1 malocclusions with successful occlusal results at end of active treatment  

Microsoft Academic Search

The purpose of this study was to examine long-term stability of Angle Class II, Division 1 malocclusions with successful occlusal results at the end of active appliance therapy, search for predictors of relapse, and look for characteristics associated with successful treatment. Records taken before and after treatment and a mean of 14.0 years postretention of adolescent patients treated for a

Brett C. Fidler; Jon Årtun; Donald R. Joondeph; Robert M. Little

1995-01-01

167

Long-term outcomes and risk factor analysis after pneumonectomy for active and sequela forms of pulmonary tuberculosis  

Microsoft Academic Search

Objective: The prevalence of pulmonary tuberculosis remains high in several areas of the world, and pneumonectomy is often necessary to treat the disease. We retrospectively analyzed the morbidities, mortalities, and long-term outcomes after pneumonectomy for the treatment of active tuberculosis or its sequelae. Materials and methods: Between 1981 and 2001, 94 patients underwent either pneumonectomy or pleuropneumonectomy for the treatment

Young Tae Kim; Hong Kwan Kim; Sook-Whan Sung; Joo Hyun Kim

2003-01-01

168

Spontaneous development of functionally active long-term monocytelike cell lines from channel catfish  

Microsoft Academic Search

Summary  During the course of studies involving the in vitro manipulation of channel catfish peripheral blood leukocytes, spontaneous\\u000a proliferation was observed with unexpectedly high frequency. Propagation of these spontaneously proliferating cells has resulted\\u000a in the development of long-term (>11 mo.) cell lines which stain positively for nonspecific esterase and peroxidase, are phagocytic\\u000a for latex beads, and morphologically resemble mammalian monocytes or

Abbe N. Vallejo; Catherine F. Ellsaesser; Norman W. Miller; L. William Clem

1991-01-01

169

Long-term volcanic hazard forecasts based on Somma-Vesuvio past eruptive activity  

Microsoft Academic Search

Distributions of pyroclastic deposits from the main explosive events at Somma-Vesuvio during the 8,000-year B.P.-A.D. 1906 time-span have been analysed to provide maps of volcanic hazard for long-term eruption forecasting. In order to define hazard ratings, the spatial distributions and loads (kg\\/m2) exerted by the fall deposits on the roofs of buildings have been considered. A load higher than 300

Lucio Lirer; Paola Petrosino; Ines Alberico; Immacolata Postiglione

2001-01-01

170

Threshold responses of songbirds to long-term timber management on an active industrial forest  

USGS Publications Warehouse

Forest managers often seek to balance economic benefits from timber harvesting with maintenance of habitat for wildlife, ecosystem function, and human uses. Most research on the relationship between avian abundance and active timber management has been short-term, lasting one to two years, creating the need to investigate long-term avian responses and to identify harvest thresholds when a small change in habitat results in a disproportionate response in relative abundance and nest success. Our objectives were to identify trends in relative abundance and nest success and to identify landscape-scale disturbance thresholds for avian species and habitat guilds in response to a variety of harvest treatments (clear-cuts, heavy and light partial harvests) over 14 years. We conducted point counts and monitored nests at an industrial forest in the central Appalachians of West Virginia during 1996-1998, 2001-2003, and 2007-2009. Early successional species increased in relative abundance across all three time periods, whereas interior-edge and forest-interior guilds peaked in relative abundance mid-study after which the forest-interior guild declined. Of 41 species with >10 detections, four (10%) declined significantly, 13 (32%) increased significantly (only three species among all periods), and 9 (22%) peaked in abundance mid-study (over the entire study period, four species had no significant change in abundance, four declined, and one increased). Based on piecewise linear models, forest-interior and interior-edge guilds' relative abundance harvest thresholds were 28% total harvests (all harvests combined), 10% clear-cut harvests, and 18% light partial harvests, after which abundances declined. Harvest thresholds for the early successional guild were 42% total harvests, 11% clear-cut harvest, and 10% light partial harvests, and relative abundances increased after surpassing thresholds albeit at a reduced rate of increase after the clear-cut threshold. Threshold confidence intervals for individual species overlapped their guild threshold intervals 91% of the time. Even though relative abundance of most species (80%) did not decline as the area affected by timber management increased, implementing management at or below our approximate forest-interior and interior-edge harvest thresholds would reduce the number of declining species by half, maintain higher relative abundances of four species with a net decline in abundance but that peaked in abundance mid-study, and maintain higher relative abundances of ten additional species. In contrast, this management strategy also would prevent the increase in relative abundance of seven species and limit the increase in abundance of three species that increased throughout the study. ?? 2011 Elsevier B.V.

Becker, D. A.; Wood, P. B.; Keyser, P. D.; Wigley, T. B.; Dellinger, R.; Weakland, C. A.

2011-01-01

171

Long-term coordinated changes in the convective activity of the North Atlantic  

NASA Astrophysics Data System (ADS)

The North Atlantic is a peculiarly convective ocean. The convective renewal of intermediate and deep waters in the Labrador Sea and Greenland/Iceland Sea both contribute significantly to the production and export of North Atlantic Deep Water, thus helping to drive the global thermohaline circulation, while the formation and spreading of 18-Degree Water at shallow-to-intermediate depths off the US eastern seaboard is a major element in the circulation and hydrographic character of the west Atlantic. For as long as time-series of adequate precision have been available to us, it has been apparent that the intensity of convection at each of these sites, and the hydrographic character of their products have been subject to major interannual change, as shown by AAGAARD (1968), CLARKE, SWIFT, REID and KOLTERMANN (1990), and MEINCKE, JONSSON and SWIFT (1992) for the Greenland Sea, in the OWS BRAVO record from the Labrador Sea, (eg LAZIER, 1980 et seq.), and at the Panulirus / Hydrostation “S” site in the Northern Sargasso off Bermuda (eg JENKINS, 1982, TALLEY and RAYMER, 1982). This paper reviews the recent history of these changes showing that the major convective centres of the Greenland and Labrador Seas are currently at opposite convective extrema in our postwar record, with vertical exchange at the former site limited to 1000 m or so, but with Labrador Sea convection reaching deeper than previously observed, to over 2300 m. As a result, the deep water of the Greenland Sea has become progressively warmer and more saline since the early '70s as a result of increased horizontal exchange with the Arctic Ocean through Fram Strait, while the Labrador Sea Water has become progressively colder and fresher over the same period through increased vertical exchange; most recently, convection has become deep enough there to reach into the more saline NADW which underlies it, so that cooler, but now saltier and denser LSW has resulted. The horizontal spreading of these changing watermasses in the northern gyre is described from the hydrographic record. The theory is advanced that the scales of atmospheric forcing have imposed a degree of synchrony on convective behaviour at all three sites over the present century, with ventilation at the Sargasso and Greenland Sea sites undergoing a parallel multi-decadal evolution to reach a long term maximum in the 1960s, driven by the twin cells of the North Atlantic Oscillation (NAO). During the NAO minimum of the 1960s, with an extreme Greenland ridge feeding record amounts of fresh water into the northern gyre in the form of the Great Salinity Anomaly, and its partner cell over the Southeast USA causing a southwestward retraction of storm activity ( DICKSON and NAMIAS, 1976), the surface freshening and postwar minimum in storm activity in the intervening area of the Labrador Sea also brought a progressive reduction, and ultimately a cessation, of wintertime convection there during the 1960s. In other words, the evolution of winter convective activity during the century was in phase but of different sign at the three sites. In these events, we see strong evidence of a direct impact of the shifting atmospheric circulation on the ocean; while this certainly does not rule out either feedbacks from anomalous ice and SST conditions on the atmosphere, or autonomous oscillations of the ocean's overturning circulation, it does tend to minimise them.

Dickson, Robert; Lazier, John; Meincke, Jens; Rhines, Peter; Swift, James

172

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

173

Seasonal phosphatase activity in three characteristic soils of the English uplands polluted by long-term atmospheric nitrogen deposition  

Microsoft Academic Search

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 (?mol para-nitrophenol g?1 soil dry wt. h?1) ranged between 83.9 and 307 in a blanket peat (total carbon 318 mg g?1, pH 3.9), 45.2–86.4 in an acid organic grassland soil (total carbon

Benjamin L. Turner; Robert Baxter; Brian A. Whitton

2002-01-01

174

Long-term variability and impact on human health of biologically active UV radiation in Moscow  

NASA Astrophysics Data System (ADS)

Measurements of erythemally weighted UV irradiance (Qer) have been performed at the Meteorological Observatory of Moscow State University since 1999 with the UVB-1 YES pyranometers. These types of devices are broadband with a spectral sensitivity curve close to the action spectrum of erythema. Main uncertainties of UVB-1 YES measurements include the difference in spectral curves of the instrument and the action spectrum of erythema, as well as the deviation from the cosine law. These uncertainties were taken into account in the database of Qer measurements (Chubarova, 2008. Additional corrections of UVB-1 measurements at low ambient temperatures have been made. We analyze interannual, seasonal and diurnal Qer changes over the time period 1999-2012. In addition, the comparisons with the results of UV reconstruction model (Chubarova, 2008) are made. This model allows us to evaluate relative changes in Qer due to variations in total ozone, effective cloud amount transmission, aerosol and cloud optical thickness since 1968. It is important to note that the main reason for UV irradiance monitoring development is the strong influence of UV irradiance on the biosphere and especially on human health mainly on human skin (CIE, 1993, CIE, 2006) and eyes (Oriowo, M. et al., 2001). Based on the detailed studies we have shown the possibility of utilizing UVB-1 pyranometers for measuring the eye-damage UV radiation. Parallel measurements by the Bentham DTM-300 spectrometer and the UVB-1 YES pyranometer at the Innsbruck Medical University (Austria) have provided us the calibration factor in eye-damage units for this broadband instrument. Influence of main geophysical factors on different types of UV irradiance is estimated by means the RAF ideology (Booth, Madronich, 1994). We discuss the responses of different types of biologically active UV radiation to the impact of various atmospheric factors. The UV conditions (deficiency, optimum, excess for human) are analyzed according to the developed classification for Moscow. Booth, C.R. and S. Madronich, 1994: Radiation amplification factors: improved formulation accounts for large increases in ultraviolet radiation associated with Antarctic ozone depletion. In: Ultraviolet Radiation in Antarctica: Measurements and Biological Research [Weiler, C.S. and P.A. Penhale (eds.)]. AGU Antarctic Research Series, 62, Washington, DC, USA, 39-42. Chubarova N.Y., 2008: UV variability in Moscow according to long-term UV measurements and reconstruction model. Atmos.Chem.Phys., 8, 3025-3031 Oriowo, M. et al., 2001:, Action spectrum for in vitro UV-induced cataract using whole lenses. Invest.Ophthalmol.&Vis.Sci, 42, 2596-2602. CIE, 1993: Reference Action Spectra for Ultraviolet Induced Erythema and Pigmentation of Different Human skin Types. CIE Research Note, CIE Technical Collection., N.3 CIE, 2006: Action spectrum for the production of previtamin D3 in human skin, Technical report 174, International commission on illumination

Zhdanova, Ekaterina; Chubarova, Natalia

2014-05-01

175

Short-term and long-term reproducibility of lung tumor position using active breathing control (ABC)  

SciTech Connect

Purpose: To evaluate the short-term and long-term reproducibility of lung tumor position for scans acquired using an active breathing control (ABC) device. Methods and Materials: Ten patients with lung cancer were scanned over three sessions during the course of treatment. For each session, two scans were acquired at deep inhale, and one scan each at half of deep inhale and at exhale. Long-term reproducibility was evaluated by comparing the same breathing state scans from two sessions, with setup variation removed by skeletal alignment. Tumor alignment was based on intensity matching of a small volume around the tumor. For short-term reproducibility, the two inhale volumes from the same session were compared. Results: For the short-term reproducibility, the mean and the standard deviation (SD) of the displacement of the center of tumor were 0.0 (1.5) mm in anteroposterior (AP), 0.3 (1.4) mm in superior/inferior (SI), and 0.2 (0.7) mm in right/left (RL) directions. For long-term reproducibility, the mean (SD) were -1.3 (3.1) mm AP, -0.5 (3.8) mm SI, and 0.3 (1.6) mm RL for inhale and -0.2 (2.8) mm AP, 0.2 (2.1) mm SI, and -0.7 (1.1) mm RL for exhale. Conclusion: The ABC device demonstrates very good short-term and long-term reproducibility. Increased long-term variability in position, primarily in the SI and AP directions, indicates the role of tumor-directed localization in combination with breath-held immobilization.

Koshani, Rojano [Department of Radiation Oncology, University of Michigan, Ann Arbor, MI (United States)]. E-mail: rkashani@umich.edu; Balter, James M. [Department of Radiation Oncology, University of Michigan, Ann Arbor, MI (United States); Hayman, James A. [Department of Radiation Oncology, University of Michigan, Ann Arbor, MI (United States); Henning, George T. [Department of Radiation Oncology, St. Joseph Mercy Hospital, Ann Arbor, MI (United States); Herk, Marcel van [Department of Radiation Oncology, Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital (NKI-AVL), Amsterdam (Netherlands)

2006-08-01

176

Optimising long-term participation in physical activities after stroke: exploring new ways of working for physiotherapists.  

PubMed

There is now good empirical evidence of physical and functional benefits for individuals with stroke from long-term engagement in a range of physical activities. However, long-term participation of stroke survivors in physical activity after rehabilitation is low, and maximum benefits are not being achieved. This article reviews relevant literature and evidence, and suggests that physiotherapists are ideally placed to support patients in long-term participation in activity as they prepare patients for the end of physical rehabilitation. However, this requires the development, testing and application of stroke-specific evidence-based behavioural and motivational interventions that are feasible in clinical practice, take account of the role of carers, and seek to address the barriers to activity faced by stroke survivors at the end of rehabilitation. It also requires physiotherapists to take a leading role in developing appropriate policies and strategies with other exercise professionals and services to address the transition from rehabilitation to an active lifestyle following stroke. PMID:19635344

Morris, Jacqui H; Williams, Brian

2009-09-01

177

Direct Normal Solar Radiation Data Manual: Long-Term, Monthly Mean, Daily Totals for 235 National Weather Service Stations. Addendum to the Insolation Data Manual.  

National Technical Information Service (NTIS)

Average monthly data are presented that depict the long-term geographic distribution of direct normal solar radiation in the US. Some terms are defined, the ADIPA model for estimating hourly direct normal insolation is described, and its validation is dis...

C. L. Knapp T. L. Stoffel

1982-01-01

178

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

179

QCM study of microbiological activity during long-term exposure to atmosphere—aluminium colonisation by Aspergillus Niger  

Microsoft Academic Search

The study demonstrated a possibility to sense the activity of microorganisms on metals in situ under atmosphere conditions\\u000a using a quartz crystal microbalance (QCM) as a sensitive mass change detector. Other innovative aspects of the QCM application\\u000a include long-term monitoring (over month), taking count of the influence of atmospheric pressure and application of Al-glued\\u000a foil electrodes. The research subject was

Povilas Mie?inskas; Konstantinas Leinartas; Virginija Uksien?; Eimutis Juzeli?nas

2007-01-01

180

Long-Term Follow-Up after High-Activity 125I Brachytherapy for Pediatric Brain Tumors  

Microsoft Academic Search

A retrospective review including long-term follow-up (4.6–12.0 years) was performed of all 28 pediatric patients who underwent high-activity 125I brachytherapy at the University of California, San Francisco, for primary or recurrent brain tumors from 1980 until 1991. There were 4 glioblastomas, 11 high-grade nonglioblastoma multiforme (NGM) malignant gliomas, 10 contrast-enhancing low-grade NGM, 2 choroid plexus carcinomas, and 1 rhabdomyosarcoma. The

Penny K. Sneed; Carolyn Russo; Cindy O. Scharfen; Michael D. Prados; Mary K. Malec; David A. Larson; Kathleen R. Lamborn; Sharon A. Lamb; Brigid Voss; Keith A. Weaver; Theodore L. Phillips; Philip H. Gutin; William M. Wara; Michael S. B. Edwards

1996-01-01

181

Inflammatory activation following interruption of long-term cardiac resynchronization therapy.  

PubMed

Previous observations suggest that cardiac resynchronization therapy (CRT) may exert an anti-inflammatory effect. The objective of this study was to evaluate the effect of temporary interruption of long-term CRT on plasma concentrations of proinflammatory cytokines and brain natriuretic peptide (BNP). The study group consisted of 54 patients (32 male and 22 female, mean age 64 years) with chronic heart failure (HF) treated with CRT. BNP, high-sensitivity C-reactive protein (hs-CRP), interleukin 6 (IL-6), and neopterin were measured three times: after 26-28 weeks of continuous CRT (CRT-on), 48 h after its cessation (CRT-off), and 48 h after switching the CRT-on again. CRT interruption resulted in a significant worsening of left ventricular systolic function: reduction of cardiac output (CO), dP/dt, and left ventricular ejection fraction (LVEF), as well as deterioration of mitral regurgitation in the CRT responder group. A significant increase in serum concentrations of hs-CRP, neopterin, IL-6, and BNP was noted in this subpopulation. In CRT nonresponders, no significant changes were observed. In responders the changes in serum concentrations of hs-CRP, IL-6, neopterin, and BNP, following CRT interruption, significantly correlated with the respective changes in thoracic fluid content (TFC) and inversely correlated with LVEF changes. Even short (48 h) interruption of long-term CRT led to a significant increase of proinflammatory cytokines and BNP concentrations in responders. The changes in hs-CRP, IL-6, neopterin, and BNP concentrations correlated with the change in TFC-marker of pulmonary congestion and inversely correlated with the change in LVEF. PMID:23242167

Rubaj, Andrzej; Ruci?ski, Piotr; Oleszczak, Krzysztof; Trojnar, Micha? K; Wójcik, Maciej; Wysoki?ski, Andrzej; Kutarski, Andrzej

2013-09-01

182

Communication activity in a social network: relation between long-term correlations and inter-event clustering  

PubMed Central

Human communication in social networks is dominated by emergent statistical laws such as non-trivial correlations and temporal clustering. Recently, we found long-term correlations in the user's activity in social communities. Here, we extend this work to study the collective behavior of the whole community with the goal of understanding the origin of clustering and long-term persistence. At the individual level, we find that the correlations in activity are a byproduct of the clustering expressed in the power-law distribution of inter-event times of single users, i.e. short periods of many events are separated by long periods of no events. On the contrary, the activity of the whole community presents long-term correlations that are a true emergent property of the system, i.e. they are not related to the distribution of inter-event times. This result suggests the existence of collective behavior, possibly arising from nontrivial communication patterns through the embedding social network.

Rybski, Diego; Buldyrev, Sergey V.; Havlin, Shlomo; Liljeros, Fredrik; Makse, Hernan A.

2012-01-01

183

Surface electromagnetic impedance and geomagnetic activity: results of long term observation  

NASA Astrophysics Data System (ADS)

The magnetotelluric (MT) method is one of the most useful geophysical tool to discover even the deep subsurface structures. The target function of the MT data processing is the surface electromagnetic (EM) impedance. In case of practical MT exploration the surface EM impedance is computed based on a simplification related to the nature of the ionospheric source of the surface EM signals. Assuming that the ionospheric current systems result in homogeneous surface electromagnetic variations, the uncertainty of the computed surface electromagnetic impedance tensor depends only the duration of the EM observation. However the surface EM field can only be approached by plane waves in certain time periods and besides given uncertainty. The EM impedance may be sensitive to magnetospheric and -indirectly- interplanetary circumstances and solar activity. Four years continuous observation of telluric and surface geomagnetic components allowed to perform a representative survey to discover if geomagnetic activity has any effect on observed EM impedance tensor. Geomagnetic indices (Dst, ULF-index, ASY-H, SYM-H) have been used to classify dates according to geomagnetic activity. Processing to estimate the mean surface EM impedance tensor has been performed in each dataset, each class separately. The sensitivity and the characteristics of the answer of the EM impedance tensor to the geomagnetic disturbances seems to be definite. This presentation aims to briefly summarize the preliminary results of our study based on the unique dataset of the Széchenyi István Geophysical Obsevatory (Intermagnet code:NCK). In addition, pointing out the limitations of the routine way of practical MT data processing and interpretation is an important duty of this study. This study was supported by the TAMOP-4.2.2.C-11/1/KONV-2012-0015 (Earth-system) project sponsored by the EU and European Social Foundation.

Lemperger, István; Menvielle, Menvielle; Wesztergom, Viktor; Bencze, Pál; Szendr?i, Judit; Novák, Attila; Kis, Árpád; Szalai, Sándor

2014-05-01

184

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.

Marschollek, Michael

2013-01-01

185

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.

Preuss, Stephanie; Stein, Wolfgang

2013-01-01

186

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

187

Viagra for your synapses: Enhancement of hippocampal long-term potentiation by activation of beta-adrenergic receptors.  

PubMed

Beta-adrenergic receptors (beta-ARs) critically modulate long-lasting synaptic plasticity and long-term memory storage in the mammalian brain. Synaptic plasticity is widely believed to mediate memory storage at the cellular level. Long-term potentiation (LTP) is one type of synaptic plasticity that has been linked to memory storage. Activation of beta-ARs can enhance LTP and facilitate long-term memory storage. Interestingly, many of the molecular signaling pathways that are critical for beta-adrenergic modulation of LTP mirror those required for the persistence of memory. In this article, we review the roles of signaling cascades and translation regulation in enabling beta-ARs to control expression of long-lasting LTP in the rodent hippocampus. These include the cyclic-AMP/protein kinase-A (cAMP-PKA) and extracellular signal-regulated protein kinase cascades, two key pathways known to link transmitter receptors with translation regulation. Future research directions are discussed, with emphasis on defining the roles of signaling complexes (e.g. PSD-95) and glutamatergic receptors in controlling the efficacy of beta-AR modulation of LTP. PMID:20043991

O'Dell, Thomas J; Connor, Steven A; Gelinas, Jennifer N; Nguyen, Peter V

2010-05-01

188

VIAGRA FOR YOUR SYNAPSES: ENHANCEMENT OF HIPPOCAMPAL LONG-TERM POTENTIATION BY ACTIVATION OF BETA-ADRENERGIC RECEPTORS  

PubMed Central

Beta-adrenergic receptors (?-ARs) critically modulate long-lasting synaptic plasticity and long-term memory storage in the mammalian brain. Synaptic plasticity is widely believed to mediate memory storage at the cellular level. Long-term potentiation (LTP) is one type of synaptic plasticity that has been linked to memory storage. Activation of ?-ARs can enhance LTP and facilitate long-term memory storage. Interestingly, many of the molecular signaling pathways that are critical for ?-adrenergic modulation of LTP mirror those required for the persistence of memory. In this article, we review the roles of signaling cascades and translation regulation in enabling ?-ARs to control expression of long-lasting LTP in the rodent hippocampus. These include the cyclic-AMP/protein kinase-A (cAMP-PKA) and extracellular signal-regulated protein kinase cascades, two key pathways known to link transmitter receptors with translation regulation. Future research directions are discussed, with emphasis on defining the roles of signaling complexes (e.g. PSD-95) and glutamatergic receptors in controlling the efficacy of ?-AR modulation of LTP.

O'Dell, Thomas J.; Connor, Steven A.; Gelinas, Jennifer N.; Nguyen, Peter V.

2010-01-01

189

Activation of Synaptic Group II Metabotropic Glutamate Receptors Induces Long-Term Depression at GABAergic Synapses in CNS Neurons  

PubMed Central

Metabotropic glutamate receptor (mGluR)-dependent homosynaptic long-term depression (LTD) has been studied extensively at glutamatergic synapses in the CNS. However, much less is known about heterosynaptic long-term plasticity induced by mGluRs at inhibitory synapses. Here we report that pharmacological or synaptic activation of group II mGluRs (mGluR II) induces LTD at GABAergic synapses without affecting the excitatory glutamatergic transmission in neurons of the chicken cochlear nucleus. Coefficient of variation and failure rate analysis suggested that the LTD was expressed presynaptically. The LTD requires presynaptic spike activity, but does not require the activation of NMDA receptors. The classic cAMP-dependent protein kinase A signaling is involved in the transduction pathway. Remarkably, blocking mGluR II increased spontaneous GABA release, indicating the presence of tonic activation of mGluR II by ambient glutamate. Furthermore, synaptically released glutamate induced by electrical stimulations that concurrently activated both the glutamatergic and GABAergic pathways resulted in significant and constant suppression of GABA release at various stimulus frequencies (3.3, 100, and 300 Hz). Strikingly, low-frequency stimulation (1 Hz, 15 min) of the glutamatergic synapses induced heterosynaptic LTD of GABAergic transmission, and the LTD was blocked by mGluR II antagonist, indicating that synaptic activation of mGluR II induced the LTD. This novel form of long-term plasticity in the avian auditory brainstem may play a role in the development as well as in temporal processing in the sound localization circuit.

Tang, Zheng-Quan; Liu, Yu-Wei; Shi, Wei; Dinh, Emilie Hoang; Hamlet, William R.; Curry, Rebecca J.

2013-01-01

190

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.

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

2010-01-01

191

SWAP Observations of the Long-term, Large-scale Evolution of the Extreme-ultraviolet Solar Corona  

NASA Astrophysics Data System (ADS)

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; Shearer, Paul; Berghmans, David; Nicula, Bogdan

2013-11-01

192

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

193

Long Term Care Study.  

National Technical Information Service (NTIS)

Long-term care needs and facilities in Saginaw, Mich., and alternatives to institutionalization were investigated. The instrument for the study was designed by the East Central Michigan Health Systems Agency. Long-term care facilities in Saginaw were surv...

1978-01-01

194

Direct normal solar radiation data manual: Long-term, monthly mean, daily totals for 235 National Weather Service stations. Addendum to the Insolation Data Manual  

Microsoft Academic Search

Average monthly data are presented that depict the long-term geographic distribution of direct normal solar radiation in the US. Some terms are defined, the model for estimating hourly direct normal insolation is described, and its validation is discussed. Direct normal radiation is then tabulated for 235 National Weather Service Stations, given as monthly and annual averages in units of kJ\\/m(2)-day,

C. L. Knapp; T. L. Stoffel

1982-01-01

195

The Total Spectrum of Solar X-rays and Its Long-Term Variation Obtained from Earth Albedo Data of ASCA GIS  

Microsoft Academic Search

We report on the spectrum of solar X-rays and its long-term variation obtained from Earth albedo data of ASCA\\/GIS. GIS is a set of gas scintillation counters which cover the energy range of 0.5--10 keV. We accumulated GIS data of the Earth albedo for the period of 1993--2000 and analyzed spectra for each year. The period spans from the declining

M. Itoh; H. Yamada; Y. Ishisaki; T. Ishikawa; T. Dotani; K. Terada

2002-01-01

196

Barriers to physical activity and restorative care for residents in long-term care: a review of the literature.  

PubMed

Despite the benefits of physical activity, residents living in long-term care (LTC) are relatively sedentary. Designing successful physical activity and restorative care programs requires a good understanding of implementation barriers. A database search (2002-2013) yielded seven studies (nine articles) that met our inclusion criteria. We also reviewed 31 randomized controlled trials (RCTs) to determine if the authors explicitly discussed the barriers encountered while implementing their interventions. Eleven RCTs (13 articles) included a discussion of the barriers. Hence, a total of 18 studies (22 articles) were included in this review. Barriers occurred at resident (e.g., health status), environmental (e.g., lack of space for physical activity), and organizational (e.g., staffing and funding constraints) levels. These barriers intersect to adversely affect the physical activity of older people living in LTC. Future studies targeting physical activity interventions for residents living in LTC are needed to address these multiple levels of influence. PMID:23434919

Benjamin, Kathleen; Edwards, Nancy; Ploeg, Jenny; Legault, Frances

2014-01-01

197

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

198

Short and Long-Term Effects of hVEGF-A165 in Cre-Activated Transgenic Mice  

PubMed Central

We have generated a transgenic mouse where hVEGF-A165 expression has been silenced with loxP-STOP fragment, and we used this model to study the effects of hVEGF-A165 over-expression in mice after systemic adenovirus mediated Cre-gene transfer. Unlike previous conventional transgenic models, this model leads to the expression of hVEGF-A165 in only a low number of cells in the target tissues in adult mice. Levels of hVEGF-A165 expression were moderate and morphological changes were found mainly in the liver, showing typical signs of active angiogenesis. Most mice were healthy without any major consequences up to 18 months after the activation of hVEGF-A165 expression. However, one mouse with a high plasma hVEGF-A165 level died spontaneously because of bleeding into abdominal cavity and having liver hemangioma, haemorrhagic paratubarian cystic lesions and spleen peliosis. Also, two mice developed malignant tumors (hepatocellular carcinoma and lung adenocarcinoma), which were not seen in control mice. We conclude that long-term uncontrolled hVEGF-A165 expression in only a limited number of target cells in adult mice can be associated with pathological changes, including possible formation of malignant tumors and uncontrolled bleeding in target tissues. These findings have implications for the design of long-term clinical trials using hVEGF-A165 gene and protein.

Leppanen, Pia; Kholova, Ivana; Mahonen, Anssi J.; Airenne, Kari; Koota, Suvi; Mansukoski, Hannu; Narvainen, Johanna; Wirzenius, Maria; Alhonen, Leena; Janne, Juhani; Alitalo, Kari; Yla-Herttuala, Seppo

2006-01-01

199

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

200

Reorganization of cortical population activity imaged throughout long-term sensory deprivation.  

PubMed

Sensory maps are reshaped by experience. It is unknown how map plasticity occurs in vivo in functionally diverse neuronal populations because activity of the same cells has not been tracked over long time periods. Here we used repeated two-photon imaging of a genetic calcium indicator to measure whisker-evoked responsiveness of the same layer 2/3 neurons in adult mouse barrel cortex over weeks, first with whiskers intact, then during continued trimming of all but one whisker. Across the baseline period, neurons displayed heterogeneous yet stable responsiveness. During sensory deprivation, responses to trimmed whisker stimulation globally decreased, whereas responses to spared whisker stimulation increased for the least active neurons and decreased for the most active neurons. These findings suggest that recruitment of inactive, 'silent' neurons is part of a convergent redistribution of population activity underlying sensory map plasticity. Sensory-driven responsiveness is a key property controlling experience-dependent activity changes in individual neurons. PMID:23086335

Margolis, David J; Lütcke, Henry; Schulz, Kristina; Haiss, Florent; Weber, Bruno; Kügler, Sebastian; Hasan, Mazahir T; Helmchen, Fritjof

2012-11-01

201

Effects of long term irrigation with polluted water and sludge amendment on some soil enzyme activities  

SciTech Connect

The objective of this study was to determine the effects of wastewater sludge-fly ash mixtures on urease, dehydrogenase, alkaline phosphatase and beta-glucosidase activities in soils. In order to evaluate the probable effects of previous soil management practices (irrigation with polluted water) on soil enzymes, two different soil samples which were similar in physical properties, but different in irrigation practice were used. The application of wastewater sludges supplemented with varying doses of fly ash increased potential enzyme activities for a short period of time (3 months) in comparison to unamended soils. However, the activity levels generally showed a decreasing trend with increasing ash ratios indicating the inhibitory effect of fly ash. The urease and dehydrogenase activities were particularly lower in soils irrigated from a polluted stream, indicating the negative effects of the previous soil management on soil microbial activity.

Topac, F.O.; Baskaya, H.S.; Alkan, U.; Katkat, A.V. [Uludag University, Bursa (Turkey)

2008-01-15

202

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

203

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

Microsoft Academic Search

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

LT Wier; GW Ayers; AS Jackson; AC Rossum; WS Carlos Poston; JP Foreyt

2001-01-01

204

Activation of cyclic AMP-dependent protein kinase is required for long-term enhancement at corticostriatal synapses in rats.  

PubMed

The induction of long-term potentiation (LTP) at corticostriatal synapses is dependent on the activation of postsynaptic NMDA receptors, but the mechanisms involved in the maintenance of LTP are not known. We report here that forskolin, an activator of adenylyl cyclase, induces a lasting enhancement of the corticostriatal synaptic response. This enhancement is associated with a lasting decrease in paired-pulse ratio, and is blocked by inhibitors of adenylyl cyclase and cyclic AMP-dependent protein kinase (PKA), but not by a PKA inhibitor injected into the postsynaptic cell. Tetanically-induced LTP is also associated with a decrease in paired-pulse ratio and partially occludes the subsequent action of forskolin. Our results suggest that activation of presynaptic PKA can enhance neurotransmission at corticostriatal synapses; a mechanism required for the expression of LTP at these synapses. PMID:12165416

Spencer, Jonathan P; Murphy, Kerry P S J

2002-08-30

205

In Vivo Long-Term Magnetic Resonance Imaging Activity of Ferritin-Based Magnetic Nanoparticles versus a Standard Contrast Agent.  

PubMed

New long-circulating maghemite nanoparticles of 4 and 6 nm, coated with an apoferritin protein capsid, exhibit useful properties to act as magnetic resonance imaging (MRI) contrast agents. A full in vivo study of the so-called apomaghemites reveals that their long-term MRI properties are better than those of a standard superparamagnetic iron oxide (SPIO) widely used in biomedical applications. The biodistribution of apomaghemites and standard SPIO was investigated by MRI in mice at two different concentrations, 6 and 2.5 mg of Fe·kg(-1), over 60 days. Significant differences are found at low dose (2.5 mg of Fe·kg(-1)). Thus, whereas apomaghemites are active for MR bioimaging of liver for 45 days, standard SPIO is not effective beyond 7 days. On the basis of our data, we may concluded that apomaghemites can act as new long-term MRI liver contrast agents, allowing first the diagnosis of a liver pathology and then monitoring after treatment without the need for a second injection. PMID:24901375

Valero, Elsa; Fiorini, Silvia; Tambalo, Stefano; Busquier, Heriberto; Callejas-Fernández, José; Marzola, Pasquina; Gálvez, Natividad; Domínguez-Vera, José M

2014-07-10

206

Long-term outcome and prediction models of activities of daily living in Alzheimer disease with cholinesterase inhibitor treatment.  

PubMed

In untreated patients with Alzheimer disease (AD) the functional ability is gradually lost. What happens to the patients after continuous long-term cholinesterase inhibitor (ChEI) treatment is less investigated. The objective of this study was to describe the longitudinal functional outcome and analyze factors affecting the outcome in ChEI-treated patients. In an open, 3-year, nonrandomized, prospective, multicenter study in a routine clinical setting, 790 patients were treated with either donepezil, rivastigmine, or galantamine. At baseline and every 6 months, they were assessed with several rating scales including Instrumental Activities of Daily Living (IADL), Physical Self-Maintenance Scale (PSMS), and Mini-Mental State Examination (MMSE). A faster functional decline was associated with lower cognitive ability at baseline, older age, and the interaction of higher education and longer time in the study. The patients residing with a spouse or relative showed slower deterioration in IADL score. A higher mean dose of ChEI, regardless of drug agent, was also related to slower instrumental ADL decline. Prediction models for longitudinal functional outcome were provided. AD severity at baseline is a key factor in obtaining reliable clinical prognoses of the long-term ADL ability. The dosage of ChEI treatment could possibly lead to a different functional outcome. PMID:20847636

Wattmo, Carina; Wallin, Åsa K; Londos, Elisabet; Minthon, Lennart

2011-01-01

207

Interferon-beta-1b-induced short- and long-term signatures of treatment activity in multiple sclerosis  

PubMed Central

Interferon beta (IFN?) reduces disease burden in relapsing-remitting multiple sclerosis (MS) patients. In this study, IFN?-1b-treated MS patient gene expression profiles and biological knowledgebases were integrated to study IFN?'s pleiotropic mechanisms of action. Genes involved in immune regulation, mitochondrial fatty acid metabolism and antioxidant activity were discovered. Plausible mediators of neuronal preservation included NRF2, downregulation of OLA1, an antioxidant suppressor, and the antioxidant gene ND6, implicated in optic neuropathy and MS-like lesions. Network analysis highlighted IKBKE, which likely has a role in both viral response and energy metabolism. A comparative analysis of therapy-naive MS- and IFN?-associated gene expression suggests an IFN? insufficiency in MS. We observed more gene expression changes in long-term treatment than during acute dosing. These distinct short- and long-term effects were driven by different transcription factors. Multi-gene biomarker signatures of IFN? treatment effects were developed and subsequently confirmed in independent IFN?-1b-treated MS studies, but not in glatiramer acetate-treated patients.

Croze, E; Yamaguchi, K D; Knappertz, V; Reder, A T; Salamon, H

2013-01-01

208

MEG Can Map Short and Long-Term Changes in Brain Activity following Deep Brain Stimulation for Chronic Pain  

PubMed Central

Deep brain stimulation (DBS) has been shown to be clinically effective for some forms of treatment-resistant chronic pain, but the precise mechanisms of action are not well understood. Here, we present an analysis of magnetoencephalography (MEG) data from a patient with whole-body chronic pain, in order to investigate changes in neural activity induced by DBS for pain relief over both short- and long-term. This patient is one of the few cases treated using DBS of the anterior cingulate cortex (ACC). We demonstrate that a novel method, null-beamforming, can be used to localise accurately brain activity despite the artefacts caused by the presence of DBS electrodes and stimulus pulses. The accuracy of our source localisation was verified by correlating the predicted DBS electrode positions with their actual positions. Using this beamforming method, we examined changes in whole-brain activity comparing pain relief achieved with deep brain stimulation (DBS ON) and compared with pain experienced with no stimulation (DBS OFF). We found significant changes in activity in pain-related regions including the pre-supplementary motor area, brainstem (periaqueductal gray) and dissociable parts of caudal and rostral ACC. In particular, when the patient reported experiencing pain, there was increased activity in different regions of ACC compared to when he experienced pain relief. We were also able to demonstrate long-term functional brain changes as a result of continuous DBS over one year, leading to specific changes in the activity in dissociable regions of caudal and rostral ACC. These results broaden our understanding of the underlying mechanisms of DBS in the human brain.

Mohseni, Hamid R.; Smith, Penny P.; Parsons, Christine E.; Young, Katherine S.; Hyam, Jonathan A.; Stein, Alan; Stein, John F.; Green, Alexander L.; Aziz, Tipu Z.; Kringelbach, Morten L.

2012-01-01

209

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.

2014-01-01

210

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

211

Long term CO 2 enrichment stimulates N-mineralisation and enzyme activities in calcareous grassland  

Microsoft Academic Search

Elevated concentration of atmospheric carbon dioxide will affect carbon cycling in terrestrial ecosystems. Possible effects include increased carbon input into the soil through the rhizosphere, altered nutrient concentrations of plant litter and altered soil moisture. Consequently, the ongoing rise in atmospheric carbon dioxide might indirectly influence soil biota, decomposition and nutrient transformations.N-mineralisation and activities of the enzymes invertase, xylanase, urease,

Diana Ebersberger; Pascal A Niklaus; Ellen Kandeler

2003-01-01

212

The level of physical activity in long-term survivors of testicular cancer.  

PubMed

The aim of this study was to estimate the level of physical activity (LPA) in a large cohort of testicular cancer survivors (TCSs) and compare these results with observations from men in the same age range in the general population (GenPop). We also wanted to identify parameters that influenced physical activity. The study populations consisted of 1276 TCSs treated with surgery, radiotherapy or chemotherapy with or without surgery (mean observation time was 12 years), and 20391 male inhabitants from a Norwegian county (GenPop). All completed a question investigating two sub-levels of physical activity. The logistic regression analysis adjusting for different covariates, showed significantly more physically active men among the TCSs compared with the GenPop (43 versus 37%) (adjusted odds ratio (aOR)=1.32 (95% Confidence Interval (CI) 1.10-1.58)). The results indicate that the experience of testicular cancer increases rather than reduces the LPA in TCSs, independent of treatment given. PMID:12763208

Thorsen, L; Nystad, W; Dahl, O; Klepp, O; Bremnes, R M; Wist, E; Fosså, S D

2003-06-01

213

Enzyme activities in vineyard soils long-term treated with copper-based fungicides  

Microsoft Academic Search

Copper-based fungicides have been applied in vineyard soils for a long time, which has resulted in increasing soil Cu concentration. However, information relating to non-target effects of these fungicides on microorganisms of these soils is scarce. The aim of this study was to determine the potential enzyme activities of vineyard soils in relation to Cu content and evaluate the potential

David Fernández-Calviño; Pedro Soler-Rovira; Alfredo Polo; Montserrat Díaz-Raviña; Manuel Arias-Estévez; César Plaza

2010-01-01

214

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

215

Hippocampal Inactivation with TTX Impairs Long-Term Spatial Memory Retrieval and Modifies Brain Metabolic Activity  

PubMed Central

Functional inactivation techniques enable studying the hippocampal involvement in each phase of spatial memory formation in the rat. In this study, we applied tetrodotoxin unilaterally or bilaterally into the dorsal hippocampus to evaluate the role of this brain structure in retrieval of memories acquired 28 days before in the Morris water maze. We combined hippocampal inactivation with the assessment of brain metabolism using cytochrome oxidase histochemistry. Several brain regions were considered, including the hippocampus and other related structures. Results showed that both unilateral and bilateral hippocampal inactivation impaired spatial memory retrieval. Hence, whereas subjects with bilateral hippocampal inactivation showed a circular swim pattern at the side walls of the pool, unilateral inactivation favoured swimming in the quadrants adjacent to the target one. Analysis of cytochrome oxidase activity disclosed regional differences according to the degree of hippocampal functional blockade. In comparison to control group, animals with bilateral inactivation showed increased CO activity in CA1 and CA3 areas of the hippocampus during retrieval, while the activity of the dentate gyrus substantially decreased. However, unilateral inactivated animals showed decreased CO activity in Ammon's horn and the dentate gyrus. This study demonstrated that retrieval recruits differentially the hippocampal subregions and the balance between them is altered with hippocampal functional lesions.

Conejo, Nelida Maria; Cimadevilla, Jose Manuel; Gonzalez-Pardo, Hector; Mendez-Couz, Marta; Arias, Jorge Luis

2013-01-01

216

Long-Term Norms and Cognitive Structures as Shapers of Television Viewer Activity.  

ERIC Educational Resources Information Center

Describes a study of high school students that examined responses to a music video dealing with teenage pregnancy. Students' motivations for viewing music videos, experiences with sex and pregnancy, and family communication patterns are related to the cognitive activities of thinking about the video content and relating it to their own lives. (20…

Thompson, Margaret; And Others

1991-01-01

217

Perspectives and experiences related to physical activity of elders in long-term-care settings.  

PubMed

This qualitative study investigated individual and situational factors influencing physical activity (PA) practices of elders in residential-care/assisted-living (RC/AL) communities. This article describes the results of focus-group interviews involving 47 residents across 6 RC/AL settings. Thematic analysis revealed 6 themes: staying active, past PA experiences, value of PA, barriers to PA, strategies to facilitate PA, and support needs to promote PA. Staying active meant walking indoors and out, attending chair-exercise programs, performing professionally prescribed home exercises, and using available exercise equipment. Past PA experiences shaped current preferences and practices. Participants agreed that exercise helped maintain physical functioning but recounted cognitive and situational barriers to PA. Lack of dedicated exercise space and short corridors hampered efforts to stay active. Participants wished for individualized home exercise programs and supervised exercise sessions. Future research should examine the extent to which the physical environment and PA programming in RC/AL communities affect elders' PA. PMID:22715114

Phillips, Lorraine J; Flesner, Marcia

2013-01-01

218

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

219

Long-term changes in natural killer activity after external pelvic radiotherapy. [X ray  

SciTech Connect

Peripheral lymphocytes from 24 Stage I endometrial cancer patients treated 3 to 5 years earlier were tested for their natural killer (NK) cell activity against K562 cell line targets and for surface markers. The patients were free of recurrence at the time of investigation. They belonged to a clinical trial where group A (control) received surgery only and group B also received 4000 rad external pelvic field irradiation post surgery. Lymphocyte suspensions from group B patients showed, on a per cell basis, a higher NK activity and a higher percentage of cells bearing receptors for the Fc part of immunoglobulin G than did group A lymphocytes. Expressed per volume unit of blood, however, these differences were insignificant. A depletion of T lymphocytes from the peripheral circulation was seen 3 to 5 years after radiotherapy. On a per cell basis, however, the T cell functional capacity, as estimated from the mitogenic (PHA) response, seemed unaffected.

Onsrud, M.; Thorsby, E.

1981-05-01

220

Effects of drying on nitrification activity in zeoponic medium used for long-term space missions  

NASA Technical Reports Server (NTRS)

One component of a proposed life support system is the use of zeoponic substrates, which slowly release NH4+ into "soil" solution, for the production of plants. Nitrifying bacteria that convert NH4+ to NO3- are among the important microbial components of these systems. Survival of nitrifying bacteria in dry zeoponic substrates is needed, because the substrate would likely be stored in an air-dry state between croppings. Substrate was enriched for nitrifying bacteria and allowed to air-dry in a laminar flow hood. Stored substrate was analyzed for nitrifier survivability by measuring nitrifier activity at the beginning, 3 days, 1, 2, and 3 weeks. After rewetting, activity was approximately 9 micrograms N g-1 h-1 regardless of storage time. Nitrification rates did not decrease during storage. It seems unlikely that drying between plantings would result in practical reductions in nitrification, and reinoculation with nitrifying bacteria would not be necessary.

McGilloway, R. L.; Weaver, R. W.

2004-01-01

221

Long-term repeatability of force, endurance time and muscle activity during isometric contractions  

Microsoft Academic Search

We determined the repeatability and correlations between force, endurance and muscle activity during isometric contractions over three years. Twenty-six subjects, with and without complaints of the shoulder and neck, performed standardized maximal and submaximal shoulder-abduction contractions and wrist extension-contractions at yearly intervals from 1997 to 1999. Peak forces developed during maximal contraction and the endurance times of submaximal contractions during

C. Røe; Ó. A. Steingrímsdóttir; S. Knardahl; E. S. Bakke; N. K. Vøllestad

2006-01-01

222

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

223

Long-term antibacterial efficacy of air plasma-activated water  

NASA Astrophysics Data System (ADS)

Indirect air dielectric barrier discharge in close proximity to water creates an acidified, nitrogen-oxide containing solution known as plasma-activated water (PAW), which remains antibacterial for several days. Suspensions of E. coli were exposed to PAW for either 15 min or 3 h over a 7-day period after PAW generation. Both exposure times yielded initial antibacterial activity corresponding to a ~5-log reduction in cell viability, which decreased at differing rates over 7 days to negligible activity and a 2.4-log reduction for 15 min and 3 h exposures, respectively. The solution remained at pH ~2.7 for this period and initially included hydrogen peroxide, nitrate and nitrite anions. The solution composition varied significantly over this time, with hydrogen peroxide and nitrite diminishing within a few days, during which the antibacterial efficacy of 15 min exposures decreased significantly, while that of 3 h exposures produced a 5-log reduction or more. These results highlight the complexity of PAW solutions where multiple chemical components exert varying biological effects on differing time scales.

Traylor, Matthew J.; Pavlovich, Matthew J.; Karim, Sharmin; Hait, Pritha; Sakiyama, Yukinori; Clark, Douglas S.; Graves, David B.

2011-11-01

224

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

225

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

226

Long-Term Physical Activity and Inflammatory Biomarkers in Older Adults  

PubMed Central

Purpose To determine the effects of a 12-month physical activity intervention on inflammatory biomarkers in elderly men and women. Methods 424 elderly (aged 70–89 years), nondisabled, community-dwelling men and women at risk for physical disability were enrolled in a multicenter, single-blind, randomized controlled-trial. Participants were randomized to participate in either a 12-month moderate-intensity physical activity (PA) intervention or a successful aging (SA) health education intervention. Biomarkers of inflammation (IL-6sR, IL-1sRII, sTNFRI, sTNFRII, IL-8, IL-15, adiponectin, IL-1ra, IL-2sR?, and TNF-?) were measured at baseline, 6 and 12 months. Results A baseline blood sample was successfully collected from 368 participants. After adjustment for gender, clinic site, diabetes status, and baseline outcome measure, IL-8 was the only inflammatory biomarker affected by the PA intervention (p=0.03). The adjusted mean IL-8 at month 12 was 9.9% (0.87 pg/mL) lower in the PA compared to the SA group. Secondary interaction analyses between baseline biomarker status and treatment showed one significant interaction (p=0.02) such that the PA intervention reduced IL-15 concentrations in participants with a baseline IL-15 above the median value of 1.67 pg/mL. However, these associations were no longer significant after consideration for multiple comparisons. Conclusions Overall, this study does not provide definitive evidence for an effect of regular exercise for altering systemic concentrations of the measured inflammatory biomarkers in older adults.

Beavers, Kristen M.; Hsu, Fang-Chi; Isom, Scott; Kritchevsky, Stephen B.; Church, Timothy; Goodpaster, Bret; Pahor, Marco; Nicklas, Barbara J.

2010-01-01

227

Implications of subzero metabolic activity on long-term microbial survival in terrestrial and extraterrestrial permafrost.  

PubMed

The survival of microorganisms over extended time frames in frozen subsurface environments may be limited by chemical (i.e., via hydrolysis and oxidation) and ionizing radiation-induced damage to chromosomal DNA. In an effort to improve estimates for the survival of bacteria in icy terrestrial and extraterrestrial environments, we determined rates of macromolecular synthesis at temperatures down to -15°C in bacteria isolated from Siberian permafrost (Psychrobacter cryohalolentis K5 and P. arcticus 273-4) and the sensitivity of P. cryohalolentis to ionizing radiation. Based on experiments conducted over ?400 days at -15°C, the rates of protein and DNA synthesis in P. cryohalolentis were <1 to 16 proteins cell(-1) d(-1) and 83 to 150 base pairs (bp) cell(-1) d(-1), respectively; P. arcticus synthesized DNA at rates of 20 to 1625?bp cell(-1) d(-1) at -15°C under the conditions tested. The dose of ionizing radiation at which 37% of the cells survive (D(37)) of frozen suspensions of P. cryohalolentis was 136?Gy, which was ?2-fold higher (71?Gy) than identical samples exposed as liquid suspensions. Laboratory measurements of [(3)H]thymidine incorporation demonstrate the physiological potential for DNA metabolism at -15°C and suggest a sufficient activity is possible to offset chromosomal damage incurred in near-subsurface terrestrial and martian permafrost. Thus, our data imply that the longevity of microorganisms actively metabolizing within permafrost environments is not constrained by chromosomal DNA damage resulting from ionizing radiation or entropic degradation over geological time. PMID:21087159

Amato, Pierre; Doyle, Shawn M; Battista, John R; Christner, Brent C

2010-10-01

228

Spontaneous activity at long-term silenced synapses in rat muscle.  

PubMed Central

1. The impulse activity in the sciatic nerve of rats was blocked for 30-59 days by a chronic infusion of tetrodotoxin (TTX) into a cuff around the nerve from an external mechanical pump. After this treatment the extensor digitorum longus muscle was isolated and the electrical activity at the endplates was recorded by intracellular electrodes. Endplates in the paralysed muscles were still functional as the muscle contracted briskly upon stimulation of the nerve distal to the block. 2. The spontaneous miniature endplate potentials (MEPPs) differed from those in normal muscles in having a more variable amplitude; 24% of the events were more than twice as large as the modal amplitude. In 30% of the fibres the largest of these 'giant' MEPPs (GMEPPs) triggered muscle action potentials. The amplitude distributions often had suggestive peaks indicating that the GMEPPs might consist of multiple quanta of the same size as those constituting the nerve impulse-evoked endplate potentials (EPPs). 3. The GMEPPs were more prolonged, but were similar in shape to MEPPs from normal muscles, with a smooth, relatively fast rising phase and a more prolonged decay. The mean time-to-peak was higher than for impulse-evoked EPPs of the same size, suggesting that the spontaneous release was more distant or less synchronized than after a nerve impulse. The half-decay time of the GMEPPs showed no large increase with increasing amplitude suggesting that the release of transmitter was not focal. The half-decay times were, however, longer than for impulse-evoked EPPs of the same size, suggesting that the spontaneous release might be less distributed than impulse-evoked release. 4. GMEPPs were not influenced by TTX, they were larger than the impulse-evoked EPPs in solutions containing high Mg2+ and low Ca2+, and they were not increased by high extracellular Ca2+ concentrations. Thus, the GMEPPs were not caused by spontaneous action potentials and probably not by Ca2+ influx. 5. In most cases the frequency of large and small MEPPs in paralysed muscles was influenced in the same way as those in normal muscles. It was increased by an increase in the extracellular K+ concentration or osmolarity, and reduced by a decrease in Ca2+ or an increase in Mg2+. The frequency was increased by Ruthenium Red. Also, like MEPPs in normal muscles, the frequency of small MEPPs in paralysed muscles was increased by increasing the extracellular Ca2+.(ABSTRACT TRUNCATED AT 400 WORDS)

Gundersen, K

1990-01-01

229

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

230

Long-term evolution of an activated sludge system under low dissolved oxygen conditions.  

PubMed

This study aims to evaluate the impacts of low dissolved oxygen (DO) levels on activated sludge performance. Two sequencing batch reactors (SBR), each with a working volume of 10 l, were investigated with different DO levels. Compared with high DO conditions (above 2 mg l(-1) on average), low DO conditions in the SBR did not result in poor sludge bulking, lower chemical oxygen demand, and ammonium removal efficiency. Moreover, simultaneous nitrification and denitrification (SND) via nitrite and shortcut nitrification-denitrification were carried out under low DO levels. The average efficiencies of SND and nitrite accumulation ratios (NAR) in reactors A and B were 10.6 and 60.4%, respectively, under high DO levels and 4.1 and 76%, respectively, under low DO levels. Scanning electron microscopy revealed that the main types of bacteria in reactor A were spherical and short rod-shaped bacteria, whereas those in reactor B were long rod-shaped bacteria and filamentous bacteria. Thus, the appropriate DO concentration created excellent microbial community structures, which helped the biological systems to perform well under low DO level operating conditions. PMID:24620614

Guo, Jinsong; Xu, Yufeng; Chen, Youpeng; Fan, Leilei; Fang, Fang

2013-04-01

231

Measuring social activities and social function in long-term cancer survivors who received hematopoietic stem cell transplantation  

PubMed Central

Objective Cancer survivors report deficits in social functioning even years after completing treatment. Commonly used measures of social functioning provide incomplete understanding of survivors’ social behavior. This study describes social activities of survivors and evaluates the psychometric properties of the Social Activity Log (SAL) in a cohort of long-term survivors of hematopoietic stem cell transplantation (HSCT) for cancer. Methods One hundred two 5–20 year survivors completed the SAL, Short Form-36 Health Survey (SF-36), and other patient reported outcomes. Principal components analysis determined the factor structure of the SAL along with correlations and regressions to establish validity. Results Principal component analysis yielded three factors in the SAL: “non-contact events” (eg, telephone calls), “regular events” (eg, played cards),” and “special events” (eg, concerts), which explained 59% of the total variance. The SAL possessed good internal consistency (Cronbach’s ? = 0.82). SF-36 social function and SAL were moderately correlated (r = .31). In linear regressions, physical function and depression explained 16% of the variance in the SAL (P<.001), while physical function, depression and fatigue predicted 55% of the variance in SF-36 social function (P<.001). Conclusions Results support the use of the SAL as a measure of social activity in cancer survivors who received HSCT. Whereas the SAL is designed to measure social behaviors, SF-36 social function assesses subjective experience and is more strongly associated with depression and fatigue. The SAL appears to be a promising tool to understand the behavioral social deficits reported by long-term survivors of cancer.

Syrjala, Karen L.; Stover, Allison C.; Yi, Jean C.; Artherholt, Samantha B.; Abrams, Janet R.

2011-01-01

232

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

233

Long-term effects of land application of class B biosolids on the soil microbial populations, pathogens, and activity.  

PubMed

This study evaluated the influence of 20 annual land applications of Class B biosolids on the soil microbial community. The potential benefits and hazards of land application were evaluated by analysis of surface soil samples collected following the 20th land application of biosolids. The study was initiated in 1986 at the University of Arizona Marana Agricultural Center, 21 miles north of Tucson, AZ. The final application of biosolids was in March 2005, followed by growth of cotton (Gossypium hirsutum L.) from April through November 2005. Surface soil samples (0-30 cm) were collected monthly from March 2005, 2 wk after the final biosolids application, through December 2005, and analyzed for soil microbial numbers. December samples were analyzed for additional soil microbial properties. Data show that land application of Class B biosolids had no significant long-term effect on indigenous soil microbial numbers including bacteria, actinomycetes, and fungi compared to unamended control plots. Importantly, no bacterial or viral pathogens were detected in soil samples collected from biosolid amended plots in December (10 mo after the last land application) demonstrating that pathogens introduced via Class B biosolids only survived in soil transiently. However, plots that received biosolids had significantly higher microbial activity or potential for microbial transformations, including nitrification, sulfur oxidation, and dehydrogenase activity, than control plots and plots receiving inorganic fertilizers. Overall, the 20 annual land applications showed no long-term adverse effects, and therefore, this study documents that land application of biosolids at this particular site was sustainable throughout the 20-yr period, with respect to soil microbial properties. PMID:20048328

Zerzghi, Huruy; Gerba, Charles P; Brooks, John P; Pepper, Ian L

2010-01-01

234

Long-Term Gene Therapy with Thrombospondin 2 Inhibits TGF-? Activation, Inflammation and Angiogenesis in Chronic Allograft Nephropathy  

PubMed Central

We recently identified Thrombospondin-2 (TSP-2) as a regulator of matrix remodelling and inflammation in experimental kidney disease by using TSP-2 null mice and successfully proved TSP-2 overexpression as a therapeutic concept in a short term glomerulonephritis model in the rat. In this current study, we investigated if long-term TSP-2 overexpression is also capable to ameliorate the progression of chronic kidney disease in the setting of the chronic allograft nephropathy F344-Lewis model in the rat. Two weeks after renal transplantation, two rat thigh muscles were transfected once only with either a TSP-2 overexpressing plasmid (n?=?8) or a luciferase-expressing plasmid as control (n?=?8). Rats were monitored for renal function, histological changes and gene expression in the graft for up to 30 weeks after transplantation. Unexpectedly, only in the TSP-2 treated group 2 rats died before the end of the experiment and renal function tended to be worsened in the TSP-2 group compared to the luciferase-treated controls. In addition, glomerular sclerosis and tubular interstitial injury as well as cortical fibronectin deposition was significantly increased in the TSP-2 treated kidneys despite reduced TGF-? activation and marked anti-inflammatory (macrophages, T-cells and B-cells) effects in this group. Long-term TSP-2 therapy impaired repair of renal endothelium, as demonstrated by significant higher glomerular and peritubular endothelial rarefaction and reduced endothelial cell proliferation in the transplanted kidneys from TSP-2 treated rats compared to controls. This TSP-2 effect was associated with decreased levels of renal VEGF but not VEGF1 receptor. In conclusion, despite its anti-inflammatory and TGF-? activation blocking effects, TSP-2 gene therapy did not ameliorate but rather worsened experimental chronic allograft nephropathy most likely via its anti-angiogenic properties on the renal microvasculature.

Daniel, Christoph; Vogelbacher, Regina; Stief, Andrea; Grigo, Christina; Hugo, Christian

2013-01-01

235

Time course of changes in brain activity and functional connectivity associated with long-term adaptation to a rotational transformation.  

PubMed

The purpose of this study was to examine the time course of changes in cerebral activity and functional connectivity during long-term adaptation to a visuomotor transformation. Positron emission tomography was used to measure changes in brain activity as subjects tracked a target under the influence of a rotational transformation that distorted visual feedback. The experiment was 1 week long and consisted of two scanning sessions (obtained on days 2 and 7), aimed at examining early and late stages of learning. On average, visuomotor adaptation was achieved within 3 days. During early stages of adaptation, better performance was associated with greater activity in brain areas related to attention including bilateral dorso- and ventrolateral prefrontal cortices, frontal eye fields, and the human homologue of area MT. However, as adaptation proceeded, improvements in performance were associated with greater activity in motor regions such as the left (contralateral) sensorimotor cortex, bilateral anterior cerebellum, left cingulate motor area, right putamen, and a nonmotor region within the middle temporal gyrus. This learning-specific shift in brain activity was associated with a progressive change in the functional connectivity of these regions toward the end of the first session. Interestingly, only the functional connections between the anterior cerebellum, left middle temporal gyrus, and left sensorimotor cortex remained strong once visuomotor adaptation was achieved. Our findings suggest that visuomotor adaptation is not only reflected in persistent changes in activity in motor-related regions, but also in the strengthening and maintenance of specific functional connections. PMID:15574799

Della-Maggiore, Valeria; McIntosh, Anthony R

2005-04-01

236

Long-term potentiation at C-fibre synapses by low-level presynaptic activity in vivo  

PubMed Central

Inflammation, trauma or nerve injury trigger low-level activity in C-fibres and may cause long-lasting hyperalgesia. Long-term potentiation (LTP) at synapses of primary afferent C-fibres is considered to underlie some forms of hyperalgesia. In previous studies, high- but not low-frequency conditioning stimulation of C-fibres has, however, been used to induce LTP in pain pathways. Recently we could show that also conditioning low-frequency stimulation (LFS) at C-fibre intensity induces LTP in vitro as well as in the intact animal, i.e. with tonic descending inhibition fully active. In the slice preparation, this form of LTP requires a rise in postsynaptic Ca2+-concentration and activation of Ca2+-dependent signalling pathways. Here, we investigated the signalling mechanisms underlying this novel form of LTP in vivo. We found that the signal transduction pathways causing LFS-induced LTP in vivo include activation of neurokinin 1 and N-methyl-D-aspartate receptors, rise of [Ca2+]i from intracellular stores and via T-type voltage-dependent Ca2+ channels, activation of phospholipase C, protein kinase C and Ca2+-calmodulin dependent kinase II. These pathways match those leading to hyperalgesia in behaving animals and humans. We thus propose that LTP induced by low-level activity in C-fibres may underlie some forms of hyperalgesia.

Drdla, Ruth; Sandkuhler, Jurgen

2008-01-01

237

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

238

Long-term stellar variability  

NASA Astrophysics Data System (ADS)

Stars with significant subsurface convection zones develop magnetic loop structures that, arising from the surface upward to the external atmospheres, cause flux variability detectable throughout the whole electromagnetic spectrum. In fact, diagnostics of magnetic activity are in radio wavelengths, where gyrosincrotron radiation arises from the quiescent and flaring corona; in the optical region, where important signatures are the Balmer lines, the Ca ii IRT and H&K lines; in the UV and X ray domains, the latter mainly due to coronal thermal plasma. The zoo of different magnetic features observed for the Sun - spots, faculae, flares, CMEs - are characterized by different temporal evolution and energetics, both in quantity and quality. As a consequence, the time scale of variability, the amount of involved energy and the quality of the involved photons are used as fingerprints in interpreting the observed stellar variability in the framework of the solar-stellar analogy. Here I review main results from long-term multiwavelength observations of cool star atmospheres, with emphasis to similarities and differences with the solar case.

Pagano, Isabella

2010-02-01

239

General Surgery among Long-Term Residents with and without Active Epilepsy at the Kork Epilepsy Centre – A Prospective Comparative One-Year Survey  

Microsoft Academic Search

Background\\/Aims: We prospectively assessed the frequency, type, severity and cause of treatment among the long-term residents of the Kork Epilepsy Centre in the year 2005. Methods: All long-term residents were exclusively referred to the general surgeon practicing on the campus. Patients were divided into 2 groups comprising 285 patients with active epilepsy and 53 controls who either never had epileptic

Bernhard J. Steinhoff; Ralph Hartmann; Matthias Luy; Angelika Rombach; Gerhard Ziegler; Jürgen Schulte-Mönting; Frank G. Gilliam

2010-01-01

240

Preventing Long-Term Risk of Obesity for Two Generations: Prenatal Physical Activity Is Part of the Puzzle  

PubMed Central

Background. The period surrounding pregnancy has been identified as a risk period for overweight/obesity in both mother and child because of excessive gestational weight gain (GWG). The promotion of a healthy GWG is therefore of paramount importance in the context of the prevention of obesity in the current and next generations. Objective. To provide a comprehensive overview of the effect of prenatal physical activity interventions, alone or in combination with nutritional counselling, on GWG and to address whether preventing excessive GWG decreases the incidence of infant high birth weight and/or postpartum weight retention. Method. A search of the PubMed database was conducted to identify all relevant studies. Nineteen studies were included in this review: 13 interventions combining physical activity, nutrition, and GWG counselling and 6 interventions including physical activity alone. Results. Prenatal lifestyle interventions promoting healthy eating and physical activity habits appear to be the most effective approach to prevent excessive GWG. Achievement of appropriate GWG may also decrease the incidence of high infant birth weight and postpartum weight retention. Conclusion. Healthy eating habits during pregnancy, combined with an active lifestyle, may be important elements in the prevention of long-term risk of obesity for two generations.

Ruchat, Stephanie-May; Mottola, Michelle F.

2012-01-01

241

A study of the influence of the Ga content on the long-term stability of Cu(In,Ga)Se 2 thin film solar cells  

Microsoft Academic Search

We have studied the long-term stability of a set of CuIn1?xGaxSe2 solar cells with different Ga-contents x={0, 0.3, 0.4, 0.5, 0.6, 1} during 800 h of accelerated ageing in both dry and damp heat (DaH) conditions. Device performance has been monitored with quantum efficiency and current–voltage measurements at varying temperatures (J(V)T). All samples but that with x=1 are stable in

J. Malmstrom; J. Wennerberg; L. Stolt

2003-01-01

242

Subsurface geology of Uemachi Fault zone in Osaka urban area, central Japan and its long-term activity  

NASA Astrophysics Data System (ADS)

In Osaka area of central Japan, Uemachi Fault zone is located. Uemachi Fault zone exist in the Osaka urban area and runs mainly in N-S direction with more than 40 km in length. Pliocene to Quaternary sediment 'Osaka Group' and terrace sediment are found in the Osaka Plain and Holocene marine clay layers (Ma13) are covered these plains due to global sea level change. These sediments since late Pliocene time (about 3Ma) are thick of more than 1,000m and 15 marine transgressive sediments (marine clay) according to the global glacial - interglacial cycles and many volcanic ash layers, and those marine clays and volcanic ash layers have an important role of time markers for considering subsurface structure and the long term activity of fault movement. We have seismic reflection data and gravity data, geotechnical borehole and geological borehole database in Osaka sedimentary basin area, and those data and new drilling data carried out in 2010 and 2011 are used for this study to understand the subsurface geology of the fault zone and long term activity of fault. From the geophysical data, basement displacement of Uemachi Fault at central part of fault trace is estimated about 800m by geophysical data (seismic reflection and gravity). Bore hole database indicate that total displacement of Uemachi fault zone is about 0.5 m/ky, though distribution of fault zone sprays two directions of main trace of N-S direction and two NNE-SSW flexure traces. Activity of flexure trace is calculated as 0.18 - 0.26 m/ky (northern flexure zone: Sakuragawa flexure) and 0.26 m/ky (southern flexure zone: Suminoe flexure) by geological drilling carried out 2010 and 2011. Activity of N-S main trace is about 0.11 - 0.14 m/ky by borehole database and stratigraphy of former geological drilling. As a result, recent activity of flexure zone running at western part of fault zone is higher than eastern main N-S trace. This research is funded by the integrated research project for the Uemachi active fault system in FY2010-2013 by MEXT.

Takemura, K.; Kitada, N.; Inoue, N.; Echigo, T.; Mitamura, M.

2013-12-01

243

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.

244

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

245

Long-term solar UV radiation reconstructed by ANN modelling with emphasis on spatial characteristics of input data  

Microsoft Academic Search

Artificial Neural Networks (ANN) are efficient tools to derive solar UV radiation from measured meteorological parameters such as global radiation, aerosol optical depths and atmospheric column ozone. The ANN model has been tested with different combinations of data from the two sites Potsdam and Lindenberg, and used to reconstruct solar UV radiation at eight European sites by more than 100

U. Feister; J. Junk; M. Woldt; A. Bais; A. Helbig; M. Janouch; W. Josefsson; A. Kazantzidis; A. Lindfors; P. N. den Outer; H. Slaper

2008-01-01

246

A method and algorithm for estimation of transmitted solar radiation and its long-term averages using Fourier series  

Microsoft Academic Search

Discrete Fourier series are often employed for representation of weather data in order to reduce hourly data computer storage space requirements. Further, they are often used to model inputs for building thermal analysis and solar energy systems analysis using periodic or frequency response methods. In such cases it is usually necessary to represent solar radiation transmitted through glazings with discrete

A ATHIENITIS

1990-01-01

247

Supervisory Predictive Control for Long-Term Scheduling of an Integrated Wind\\/Solar Energy Generation and Water Desalination System  

Microsoft Academic Search

In this work, we design a supervisory control system via model predictive control (MPC) for the optimal management and operation of an integrated wind-solar energy generation and reverse-osmosis (RO) water desalination system. The supervisory MPC is able to coordinate the wind and solar subsystems as well as a battery bank to provide enough energy to the RO subsystem so that

Wei Qi; Jinfeng Liu; Panagiotis D. Christofides

2012-01-01

248

Long-term efficacy of a printed or a Web-based tailored physical activity intervention among older adults  

PubMed Central

Background This study provides insight into the long-term efficacy (i.e. 12 month results) of the Web-based or print-delivered tailored Active Plus intervention (with and without environmental approach) to promote physical activity (PA) among the over-fifties. Differences in effect among subgroups are studied as well. Methods Intervention groups (i.e. print-delivered basic (PB; N = 439), print-delivered environmental (PE; N = 435), Web-based basic (WB; N = 423), Web-based environmental (WE; N = 432)) and a waiting list control group (N = 411) were studied in a clustered randomized controlled trial. Intervention participants received tailored advice three times within 4 months. Long-term effects (12 months after the intervention has started, i.e. 8 months after the intervention was completed) on PA (i.e. self-reported weekly minutes and days of sufficient PA) were tested using multilevel linear regression analyses. Participants’ age, gender, BMI, educational level, PA intention and the presence of a chronic physical limitation were considered to be potential moderators of the effect. Results Overall, the Active Plus intervention was effective in increasing weekly days of sufficient PA (B=0.49; p=.005), but ineffective in increasing weekly minutes of PA (B=84.59; p=.071). Per intervention condition analysis showed that the PB-intervention (Bdays=0.64; p=.002; Bmin=111.36; p=.017) and the PE-intervention (Bdays=0.70; p=.001; Bmin=157.41; p=.001) were effective in increasing days and minutes of PA. Neither Web-based conditions significantly increased PA, while the control group decreased their PA. In contrast to the intervention effect on minutes of PA, the effect on weekly days of PA was significantly moderated by the participants’ baseline intention to be sufficiently physically active. Conclusions In general, after 12 months the print-delivered interventions resulted in stronger effects than the Web-based interventions. The participants’ baseline intention was the only significant moderator of the intervention effect. All other assessed user characteristics did not significantly moderate the effect of the intervention, which might indicate that the intervention is sufficiently tailored to the different participant characteristics. Additional efforts should be taken to increase the sustainability of Web-based interventions. Trial registration Dutch Trial Register: NTR2297.

2013-01-01

249

Evidence for Human Fronto-Central Gamma Activity during Long-Term Memory Encoding of Word Sequences  

PubMed Central

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.

Meeuwissen, Esther Berendina; Takashima, Atsuko; Fernandez, Guillen; Jensen, Ole

2011-01-01

250

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

251

Occipital cortex activation by long-term repetitive tactile stimulation is necessary for object recognition in blinds: a case report.  

PubMed

Tactile vision has been approached from a variety of angles using different techniques. So far, a certain kind of object (and text) recognition has been shown, though seeing as such has not been achieved yet, and it remains unclear. Trough repetitive passive tactile stimulation perceptual processing is transferred from temporo-parietal to occipital areas, which affects object recognition. We report the results of passive tactile stimulation, as well as rTMS, applied to a 50 year old left handed blind male with over 97% loss of vision, who suffers from Peter's anomaly and microphthalmia. After 15 weeks of passive tactile stimulation, the subject showed increased activity in occipital areas associated with the development of visual-like perception which remained unchanged after three months without passive tactile stimulation. Inhibitory rTMS over the visual cortex led to noticeable reduction of spatial recognition performance and visual sensations in this subject. Stable changes in occipital cortical activity can be associated with subjective sensations of seeing. Once occipital activation has been achieved, it is necessary for spatial object recognition. Both facts highlight the implication of occipital areas in tactile vision and the cortical plasticity of passive tactile long-term stimulation in people with blindness. PMID:23819463

Ortiz, Tomás; Poch, Joaquín; Santos, Juan M; Martínez, Ana M; Ortiz-Terán, Laura; Requena, Carmen; Barcia, Juan A; de Erausquin, Gabriel A; Pascual-Leone, Alvaro

2014-06-01

252

Genetic deletion of Gadd45b, a regulator of active DNA demethylation, enhances long-term memory and synaptic plasticity.  

PubMed

Dynamic epigenetic mechanisms including histone and DNA modifications regulate animal behavior and memory. While numerous enzymes regulating these mechanisms have been linked to memory formation, the regulation of active DNA demethylation (i.e., cytosine-5 demethylation) has only recently been investigated. New discoveries aim toward the Growth arrest and DNA damage-inducible 45 (Gadd45) family, particularly Gadd45b, in activity-dependent demethylation in the adult CNS. This study found memory-associated expression of gadd45b in the hippocampus and characterized the behavioral phenotype of gadd45b(-/-) mice. Results indicate normal baseline behaviors and initial learning but enhanced persisting memory in mutants in tasks of motor performance, aversive conditioning and spatial navigation. Furthermore, we showed facilitation of hippocampal long-term potentiation in mutants. These results implicate Gadd45b as a learning-induced gene and a regulator of memory formation and are consistent with its potential role in active DNA demethylation in memory. PMID:23197699

Sultan, Faraz A; Wang, Jing; Tront, Jennifer; Liebermann, Dan A; Sweatt, J David

2012-11-28

253

Investigation of the atmospheric water-vapor content in Crimea via long-term photometric solar observations  

NASA Astrophysics Data System (ADS)

Water-vapor content determination via solar-radiation absorption measurement in the watervapor absorption band ? is described. The investigation was carried out with an automatic solar photometer, making it possible to record solar radiation in the band ? and adjacent absorption-free spectrum sections. Regular observations have been performed in Crimea (Simferopol, 44.7 N and 34.1 E) from 2001 to the present. According to the observation data, the water-vapor content W in the atmosphere of Crimea is seasonally dependent, while the annual average value is almost constant.

Terez, E. I.; Terez, G. A.; Kozak, A. V.; Kuz'min, S. V.

2013-06-01

254

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

255

Signatures of Marsili seamount activity from the ORION-GEOSTAR3 long-term seafloor multiparametric observatory experiment  

NASA Astrophysics Data System (ADS)

ORION-GEOSTAR3 (EC- 6th FP) has been the first long-term continuous geophysical and oceanographic experiment on the Marsili Seamount, Europe's largest underwater volcano of Plio-Pleistocenic age. The main scientific objective of this experiment was to detect specific signatures of Marsili activity. A deep sea multiparametric observatory was deployed on the seafloor at the base of the seamount at 3320 m b.s.l., in the period December 2003-May 2005. Among the instruments on board the observatory were: broadband seismometer, hydrophone, gravity meter, magnetometer, water sampler for laboratory analyses, 3D single point current meter, ADCP, CTD and Ph sensor, with a common accurate time reference. Multiparametric analysis shows that data are generally of good quality, showing continuous time series with only a very few gaps. Seismic, chemical, oceanographic, magnetic, and gravity data were analysed both in the time and frequency domains. This presentation will show some examples of analyses and comparisons. For instance, both the analysis of individual time series and their comparison have already shown interesting results: estimation of the lithospheric depth under the Marsili, lateral attenuation distribution of recorded seismic body waves and indications for possible existence of a hydrothermal circuit. Significant correlations between recorded time series could be related to activity and structure of the Marsili seamount revealing interesting and unknown characteristics of this submarine volcano.

de Santis, Angelo

2010-05-01

256

Nov/CCN3 regulates long-term repopulating activity of murine hematopoietic stem cells via integrin ?v?3.  

PubMed

Throughout life, hematopoietic stem cells (HSCs) sustain the blood cell supply through their capacities for self-renewal and multilineage differentiation. These processes are regulated within a specialized microenvironment termed the 'niche'. Here, we show a novel mechanism for regulating HSC function that is mediated by nephroblastoma overexpressed (Nov/CCN3), a matricellular protein member of the CCN family. We found that Nov contributes to the maintenance of long-term repopulating (LTR) activity through association with integrin ?v?3 on HSCs. The resultant ?3 integrin outside-in signaling is dependent on thrombopoietin (TPO), a crucial cytokine involved in HSC maintenance. TPO was required for Nov binding to integrin ?v?3, and stimulated Nov expression in HSCs. However, in the presence of IFN?, a cytokine known to impair HSC function, not only was TPO-induced expression of Nov suppressed, but the LTR activity was conversely impaired by TPO-mediated ligation of integrin ?v?3 with exogenous ligands, including Nov, as well. Thus, Nov/integrin ?v?3-mediated maintenance of HSCs appears to be modulated by simultaneous stimulation by other cytokines. Our finding suggests that this system contributes to the regulation of HSCs within the bone marrow niche. PMID:24563081

Ishihara, Jun; Umemoto, Terumasa; Yamato, Masayuki; Shiratsuchi, Yoshiko; Takaki, Satoshi; Petrich, Brian G; Nakauchi, Hiromitsu; Eto, Koji; Kitamura, Toshio; Okano, Teruo

2014-04-01

257

Long-Term Variations in the Occurrence and Effective Solar Transmission of Clouds as Determined from Surface-Based Total Irradiance Observations  

SciTech Connect

Time series of cloud solar transmission and cloud occurrence frequency are developed for the past 27 years at four globally remote and climatically diverse surface locations. A new methodology is developed that objectively segregates times of cloud-free conditions from those times when clouds are detected in high-time-resolution total solar irradiance observations that are obtained from pyranometers. The methodology for cloud detection depends on the magnitude and short-term variability of observed departures from clear-sky conditions. Expected clear-sky irradiances are based on interpolated clear-sky observations. Results of the new cloud detection methodology are compared to four independent cloud detection methods. An effective cloud transmission is determined as the ratio of observed irradiance in the presence of clouds to that expected in the absence of clouds. Selective forward scattering by clouds toward the observation site results in computed effective transmissions frequently being >1.0. It is shown that conditional temporal averaging of effective cloud transmission over periods of three days or more virtually eliminates the unrealistic cloud transmissions exceeding 1.0. Such temporal averaging of the surface measurements is advantageous for comparing against other area-wide cloud transmission estimates, such as those determined from satellite or by numerical climate models. The cloud occurrence frequency and the effective solar transmission for long-term observational records are summarized into monthly and annual averages, and their long-term variability is investigated. Temporal variations in frequency distributions of transmission are used to determine which clouds are responsible for changes in mean cloudiness. A statistically significant upward trend in cloud occurrence frequency, from 76% to 82% between 1976 and 2001, is detected at Barrow, Alaska, where clouds having solar transmission near 0.2 exhibit the largest increase. At the South Pole, decadal time scale oscillations in both cloud characteristics are detected, but no particular cloud category is identified as the source of that oscillation.

Dutton, Ellsworth G.; Farhadi, A.; Stone, R. S.; Long, Charles N.; Nelson, D. W.

2004-02-11

258

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

259

Orally active and long-term acting insulin-mimetic vanadyl complex:bis(picolinato)oxovanadium (IV).  

PubMed

The blood glucose level of rats with streptozotocin (STZ)-induced diabetes has been found to be normalized by administration of vanadyl or vanadate complexes. During our investigations on the development of anti-diabetic vanadyl complexes with various types of coordination mode such as V-O, V-N and V-S, we found that a new bis(picolinato)oxovanadium (IV) complex (VPA) has a strong insulin-mimetic effects as evaluated by an in vitro experiments, in which the inhibition of free fatty acid release in isolated rat adipocytes treated with epinephrine was observed to be similar to that of insulin. VPA was also effective for normalizing the blood glucose level of STZ-induced diabetic rats when given intraperitoneally or orally. The serum glucose level was maintained in the normal range for about 30 days with body weight gain after the end of oral administration of VPA for 14 days. VPA was confirmed to be an orally active and long-term acting insulin-mimetic vanadyl complex to treat insulin-dependent diabetes mellitus (IDDM) in rats. PMID:7575515

Sakurai, H; Fujii, K; Watanabe, H; Tamura, H

1995-09-25

260

Holocene mega-droughts in central India - Long-term climate variability and the possible influences of ENSO activity  

NASA Astrophysics Data System (ADS)

Understanding the variability of Indian Summer Monsoon activity and the influences of different climatic forcing factors on the monsoon strength is of high importance because of the crucial effect of monsoonal rainfall for the largely agricultural based south Asian societies. The discovery of the weakening relationship between El Niño Southern Oscillation (ENSO) and the Indian Summer Monsoon rainfall (ISM) in recent decades has raised the question about the ISM-ENSO links during the Holocene. Long term high resolution palaeoclimate data from central India, the so called "core monsoon region", can help to address this issue. Here we present the first well dated 11.5 cal ka high resolution multi-proxy record from Lonar lake, central India. Lithology, evaporites, stable isotopes, and palynological data, suggest generally moist conditions in the early to mid-Holocene, followed by a trend towards more arid conditions that started between 4.7 and 4.2cal ka BP. Moreover, we identified centennial to millennial-scale dry and wet phases throughout the Holocene and discuss possible reasons for ISM variability. Based on the comparison of the arid events from Lonar record with the available data on Holocene ENSO events we hypothesize that the rainfall variability is stronger affected by ENSO during the late Holocene, possibly caused by the weakening of summer insolation.

Prasad, Sushma; Anoop, Ambili; Menzel, Philip; Riedel, Nils; Plessen, Birgit; Basavaiah, Nathani; Gaye, Birgit; Stebich, Martina

2013-04-01

261

Long-term facilitation of social recognition in rats by vasopressin related peptides: a structure-activity study.  

PubMed

The effect of several vasopressin-related peptides was investigated in the social recognition paradigm, that consists of two successive encounters of a resident and a juvenile rat. The decrease of social investigation time of the resident rat during the second encounter served as a measure for social recognition. Single administration (3.0 micrograms, s.c.) of the vasopressin (AVP)-related peptides AVP-(1-8), AVP-(1-7) or AVP-(1-6), injected just after the first encounter, resulted in social recognition after 24 hours. Such an effect was not observed after placebo treatment or an injection with AVP-(1-5), [pGlu4, Cyt6]AVP-(4-8), [pGlu4, Cyt6]-AVP-(4-9), AVP-(7-9) or oxytocin-(1-6)-NH2. The peptide AVP-(1-6) was also active when administered in a dose of 0.3 micrograms in contrast to other peptides. Thus, vasopressin related peptides induce long term facilitation of social recognition and this action resides in the covalent ring structure of vasopressin. This effect resembles the vasopressin-induced facilitation of particular memory processes, as revealed with other behavioral paradigms. PMID:1736027

Popik, P; Van Ree, J M

1992-01-01

262

Long-term leaching behavior of phenol in cement/activated-carbon solidified/stabilized hazardous waste.  

PubMed

The long-term leaching behavior of phenol in solidified/stabilized (S/S) hazardous wastes cured for 28 d with different amounts of activated carbon (AC) was investigated using synthetic inorganic acid (H(2)SO(4):HNO(3) = 2:1, pH = 3.2), acetic acid buffer (HAc/NaAc, pH = 4.93), and deionized water as leachants to simulate the leaching of phenol in three exposure scenarios: acid-precipitation, co-disposal, and neutral-precipitation. Phenol immobilization was enhanced by AC adsorption and impaired by the growth of micropores with increasing amount of AC; thus the optimal added amount of AC to be to added S/S wastes was 2%. The leaching behavior of phenol in co-disposal scenario was unpredictable due to inadequate ionization of HAc in the HAc-NaAc buffer solution. The findings indicated that S/S products should be disposed of in hazardous waste landfills rather than municipal solid waste landfills. PMID:23270892

Liu, Jianguo; Nie, Xiaoqin; Zeng, Xianwei; Su, Zhaoji

2013-01-30

263

Modeling the long-term durability of concrete barriers in the context of low-activity waste storage  

NASA Astrophysics Data System (ADS)

The paper investigates the long-term durability of concrete barriers in contact with a cementitious wasteform designed to immobilize low-activity nuclear waste. The high-pH pore solution of the wasteform contains high concentration level of sulfate, nitrate, nitrite and alkalis. The multilayer concrete/wasteform system was modeled using a multiionic reactive transport model accounting for coupling between species, dissolution/ precipitation reactions, and feedback effect. One of the primary objectives was to investigate the risk associated with the presence of sulfate in the wasteform on the durability of concrete. Simulation results showed that formation of expansive phases, such as gypsum and ettringite, into the concrete barrier was not extensive. Based on those results, it was not possible to conclude that concrete would be severely damaged, even after 5,000 years. Lab work was performed to provide data to validate the modeling results. Paste samples were immersed in sulfate contact solutions and analyzed to measure the impact of the aggressive environment on the material. The results obtained so far tend to confirm the numerical simulations.

Protière, Y.; Samson, E.; Henocq, P.

2013-07-01

264

Solar Week Monday: Do the Activity - Measuring Solar Activity  

NSDL National Science Digital Library

This is an online lesson associated with activities during Solar Week, a twice-yearly event in March and October during which classrooms are able to interact with scientists studying the Sun. Outside of Solar Week, information, activities, and resources are archived and available online at any time. This is an activity about measurements of solar activity. Learners will observe an image of the Sun and sketch major features, plot data to begin to recognize patterns of solar activity, look for long-term patterns in graphed data, compare X-ray and visible light images of the Sun to find solar features common to both sets of images, and make a prediction of what the Sun will look like in a visible light image after observing an X-ray image taken on the same day. This activity is scheduled to occur during Monday of Solar Week.

265

Solar cycle variation of stratospheric ozone: Multiple regression analysis of long-term satellite data sets and comparisons with models  

Microsoft Academic Search

Previous multiple regression analyses of the solar cycle variation of stratospheric ozone are improved by (1) analyzing three independent satellite ozone data sets with lengths extending up to 25 years and (2) comparing column ozone measurements with ozone profile data during the 1992–2003 period when no major volcanic eruptions occurred. Results show that the vertical structure of the tropical ozone

B. E. Soukharev; L. L. Hood

2006-01-01

266

Solar cycle variation of stratospheric ozone: Multiple regression analysis of long-term satellite data sets and comparisons with models  

Microsoft Academic Search

Previous multiple regression analyses of the solar cycle variation of stratospheric ozone are improved by (1) analyzing three independent satellite ozone data sets with lengths extending up to 25 years and (2) comparing column ozone measurements with ozone profile data during the 1992-2003 period when no major volcanic eruptions occurred. Results show that the vertical structure of the tropical ozone

B. E. Soukharev; L. L. Hood

2006-01-01

267

LONG-TERM PHYSICAL ACTIVITY OUTCOMES OF HOME-BASED LIFESTYLE INTERVENTIONS AMONG BREAST AND PROSTATE CANCER SURVIVORS  

PubMed Central

Purpose Few studies have investigated long-term effects of physical activity (PA) interventions. The goal of this study was to evaluate whether or not increased levels of moderate to vigorous physical activity (MVPA) were maintained by cancer survivors one-year after receipt of two home-based interventions. Methods The FRESH START trial randomized 543 breast and prostate cancer survivors to 1-of-2 mailed print diet and exercise interventions: sequentially-tailored vs. standardized (attention control). Each arm received eight mailings over a 1-year period, with follow-up at 1- and 2-years. This analysis focuses solely on the 400 participants who had suboptimal levels of MVPA at baseline (measured by the 7-Day Physical Activity Recall) and who completed the 2-year study. Results Median minutes of MVPA at baseline, 1-year and 2-year follow-up in the tailored intervention arm were as follows: 0, 90, and 60 mins/wk, respectively. The corresponding values in the attention-control group were 0, 30, and 30 mins/wk. Significant improvements in MVPA from baseline to 2-year follow-up were observed in both study arms (p < 0.01). While significant between-arm differences were observed at 1-year follow-up (p < 0.01), by 2-year follow-up there was only the suggestion of a trend (p = 0.08). Conclusions This study provides evidence that mailed-print exercise interventions result in significant and sustainable improvements in MVPA among newly-diagnosed cancer survivors that are observed well after the intervention is complete. While tailored interventions, as compared to standardized materials, appear to produce superior improvements in MVPA initially, these differences diminish over time.

Ottenbacher, Allison J.; Day, R. Sue; Taylor, Wendell C.; Sharma, Shreela V.; Sloane, Richard; Snyder, Denise C.; Lipkus, Isaac M.; Jones, Lee W.; Demark-Wahnefried, Wendy

2013-01-01

268

CdTe thin film solar cells - direct evidence for high performance and long-term stability  

Microsoft Academic Search

Ten years ago thin-film CdTe\\/CdS p-n heterojunction solar cells were prepared by physical vapor deposition of p-CdTe films at atmospheric pressure in an inert atmosphere. Under simulated space illumination efficiencies of around 6 percent - corresponding to values of nearly 7 percent under terrestrial illumination - were measured at that time. After storage of the unencapsulated cells at normal atmosphere

D. Bonnet

1984-01-01

269

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

270

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

PubMed Central

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.

Ashok, Iyaswamy; Sheeladevi, Rathinasamy

2014-01-01

271

Long-Term Uplift in the Altiplano-Puna Neovolcanic Zone: Evidence of an Active Magmatic Diapir?  

NASA Astrophysics Data System (ADS)

We present InSAR observations of a long-term uplift in the Altiplano-Puna neovolcanic zone (central Andes, South America). Previous observations revealed a a massive Ultra Low Velocity Zone (ULVZ) at depth of 17-19 km (Zandt et al., 2003), and surface deformation that was attributed to Uturuncu, a dormant volcano in the middle of the Altiplano-Puna neovolcanic zone (Pritchard and Simons, 2002). Our time series analysis of combined data from different sensors (ERS-1/2 and ENVISAT), satellite tracks, and observation modes (fine beam and ScanSAR) reveals that the central uplift has persisted at a nearly constant rate of ~1 cm/yr over the last two decades, and is surrounded by a broad zone of subsidence. We use the satellite line-of-sight velocities from different look directions to constrain the depth and geometry of the inferred sources of magmatic unrest. Inversions based on elastic half-space models indicate that the inflation source is located well below the brittle-ductile transition, and likely resides at the depth of the seismically imaged ULVZ. We investigated the effects of inelastic deformation in the ambient crust using finite element models. The models incorporated laboratory-derived rheologies of the ambient crust, and geotherms appropriate for an active neo-volcanic zone such as the one in the Altiplano-Puna province. Based on a large number of numerical simulations constrained by the observed surface velocities, we conclude that the ongoing uplift and peripheral subsidence result from a large mid-crustal diapir fed by a partially molten source region in the middle crust. The observed pattern of surface deformation due to the Altiplano-Puna ULVZ is remarkably similar to that due to the Socorro Magma Body (SMB) in central New Mexico, USA (Pearse and Fialko, 2010), suggesting a common process. mosaic of the mean LOS velocity showing uplift and peripheral subsidence due to the inferred mid-crustal diapir.

Fialko, Y.; Pearse, J.

2012-12-01

272

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

273

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

Microsoft Academic Search

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 \\

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

2003-01-01

274

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

Microsoft Academic Search

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 per- formed in eight healthy subjects listening passively to a repeated sequence of unrelated words. Memory for the words was assessed 24 hr later with an

MICHAEL T. ALKIRE; R ICHARD J. HAIER; J AMES H. FALLON; LARRY CAHILL

275

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

276

Long-term testing  

SciTech Connect

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.

1994-12-31

277

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

278

Phrenic long-term facilitation after acute intermittent hypoxia requires spinal ERK activation but not TrkB synthesis.  

PubMed

Acute intermittent hypoxia (AIH) elicits a form of spinal respiratory plasticity known as phrenic long-term facilitation (pLTF). pLTF requires spinal serotonin receptor-2 activation, the synthesis of new brain-derived neurotrophic factor (BDNF), and the activation of its high-affinity receptor tyrosine kinase, TrkB. Spinal adenosine 2A receptor activation elicits a distinct pathway to phrenic motor facilitation (pMF); this BDNF synthesis-independent pathway instead requires new synthesis of an immature TrkB isoform. Since hypoxia increases extracellular adenosine levels, we tested the hypothesis that new synthesis of TrkB and BDNF contribute to AIH-induced pLTF. Furthermore, given that signaling mechanisms "downstream" from TrkB are unknown in either mechanism, we tested the hypothesis that pLTF requires MEK/ERK and/or phosphatidylinositol 3-kinase (PI3K)/Akt activation. In anesthetized Sprague-Dawley rats, an intrathecal catheter at cervical level 4 was used to deliver drugs near the phrenic motor nucleus. Since pLTF was blocked by spinal injections of small interfering RNAs targeting BDNF mRNA but not TrkB mRNA, only new BDNF synthesis is required for AIH-induced pLTF. Pretreatment with a MEK inhibitor (U0126) blocked pLTF, whereas a PI3K inhibitor (PI-828) had no effect. Thus, AIH-induced pLTF requires MEK/ERK (not PI3K/AKT) signaling pathways. When U0126 was injected post-AIH, pLTF development was halted but not reversed, suggesting that ERK is critical for the development but not maintenance of pLTF. Thus, there are clear mechanistic distinctions between AIH-induced pLTF (i.e., BDNF synthesis and MEK/ERK dependent) versus adenosine 2A receptor-induced pMF (i.e., TrkB synthesis and PI3K/Akt dependent). PMID:22961271

Hoffman, M S; Nichols, N L; Macfarlane, P M; Mitchell, G S

2012-10-15

279

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

280

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

281

Progress in Long-Term Trend Investigations in the Ionosphere  

NASA Astrophysics Data System (ADS)

Long-term increase of atmospheric concentration of CO2 impacts the whole atmosphere including the ionosphere. However, the ionosphere is affected also by long-term changes of geomagnetic and solar activity, by secular change of the Earth's magnetic field, by long-term changes of atmospheric wave activity and related changes in winds, and in its lower part by changes of stratospheric ozone. The ozone trend reversed in the mid-1990s. Geomagnetic activity was increasing almost throughout the last century but now it is low. Secular change of magnetic field ha strong effect in some limited areas, particularly in northern part of South America but in other regions like Europe this effect is quite negligible. The atmospheric wave activity displays regionally different and temporally unstable trends. Therefore we can hardly expect spatially homogeneous and temporally stable trends in the ionosphere. Trends in parameters of ionospheric F2, F1, E and D regions and in TEC will be briefly summarized.

Laštovi?ka, Jan

2014-05-01

282

Long-term magnetic activity of a sample of M-dwarf stars from the HARPS program . II. Activity and radial velocity  

NASA Astrophysics Data System (ADS)

Owing to their low mass and luminosity, M dwarfs are ideal targets if one hopes to find low-mass planets similar to Earth using the radial velocity (RV) method. However, stellar magnetic cycles could add noise or even mimic the RV signal of a long-period companion. We extend our previous study of the correlation between activity cycles and long-term RV variations for K dwarfs to the lower-end of the main sequence. Our objective is to detect any correlations between long-term activity variations and the observed RV of a sample of M dwarfs. We use a sample of 27 M-dwarfs with a median observational timespan of 5.9 years. The cross-correlation function (CCF) with its parameters RV, bisector inverse slope (BIS), full width at half maximum (FWHM), and contrast are computed from the HARPS spectrum. The activity index is derived using the Na i D doublet. These parameters are compared with the activity level of the stars to search for correlations. We detect RV variations up to ~5 m s-1 that we can attribute to activity cycle effects. However, only 36% of the stars with long-term activity variability appear to have had their RV affected by magnetic cycles, on the typical timescale of ~6 years. Therefore, we suggest a careful analysis of activity data when searching for extrasolar planets using long-timespan RV data. Based on observations made with the HARPS instrument on the ESO 3.6-m telescope at La Silla Observatory under programme ID 072.C-0488(E).Tables with the data used for Figs. A.1-A.27 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/541/A9Appendix A is available in electronic form at http://www.aanda.org

Gomes da Silva, J.; Santos, N. C.; Bonfils, X.; Delfosse, X.; Forveille, T.; Udry, S.; Dumusque, X.; Lovis, C.

2012-05-01

283

Activation of Protein Kinase A Contributes to the Expression But Not the Induction of Long-Term Hyperexcitability Caused by Axotomy of Aplysia Sensory Neurons  

Microsoft Academic Search

Nociceptive sensory neurons (SNs) in Aplysia provide useful models to study both memory and adaptive responses to nerve injury. Induction of long-term memory in many species, includ- ing Aplysia, is thought to depend on activation of cAMP- dependent protein kinase (PKA). Because Aplysia SNs display similar alterations in models of memory and after nerve injury, a plausible hypothesis is that

Xiaogang Liao; John D. Gunstream; Matthew R. Lewin; Richard T. Ambron; Edgar T. Walters

1999-01-01

284

Exploring Behavioral Markers of Long-Term Physical Activity Maintenance: A Case Study of System Identification Modeling within a Behavioral Intervention  

ERIC Educational Resources Information Center

Efficacious interventions to promote long-term maintenance of physical activity are not well understood. Engineers have developed methods to create dynamical system models for modeling idiographic (i.e., within-person) relationships within systems. In behavioral research, dynamical systems modeling may assist in decomposing intervention effects…

Hekler, Eric B.; Buman, Matthew P.; Poothakandiyil, Nikhil; Rivera, Daniel E.; Dzierzewski, Joseph M.; Aiken Morgan, Adrienne; McCrae, Christina S.; Roberts, Beverly L.; Marsiske, Michael; Giacobbi, Peter R., Jr.

2013-01-01

285

Cost-Effectiveness of a Long-Term Internet-Delivered Worksite Health Promotion Programme on Physical Activity and Nutrition: A Cluster Randomized Controlled Trial  

ERIC Educational Resources Information Center

This study aims to evaluate the cost-effectiveness of a long-term workplace health promotion programme on physical activity (PA) and nutrition. In total, 924 participants enrolled in a 2-year cluster randomized controlled trial, with departments (n = 74) within companies (n = 6) as the unit of randomization. The intervention was compared with a…

Robroek, Suzan J. W.; Polinder, Suzanne; Bredt, Folef J.; Burdorf, Alex

2012-01-01

286

Responses of extracellular enzyme activities and microbial community in both the rhizosphere and bulk soil to long-term fertilization practices in a fluvo-aquic soil  

Microsoft Academic Search

The influence of inorganic or organic fertilization on soil microbial ecology has been emphasized recently, but less is known about rhizosphere effects on extracellular enzyme activities and microbial community structure. Eleven extracellular enzymes involved in C, N, P, and S cycling and microbial community structure in both the rhizosphere and bulk soil samples from a long-term (31-year) fertilizer experimental field

Chao Ai; Guoqing Liang; Jingwen Sun; Xiubin Wang; Wei Zhou

287

Activation of the basolateral amygdala induces long-term enhancement of specific memory representations in the cerebral cortex.  

PubMed

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 3 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 3 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

2013-03-01

288

Active layer thickness and thaw subsidence in permafrost terrain: results from long-term observations near Barrow, Alaska  

NASA Astrophysics Data System (ADS)

Patterns of active-layer thickness (ALT) on the North Slope of Alaska are highly variable, both spatially and temporally. Although geographic patterns of ALT repeat themselves from year to year, ALT is an integrated response to a large number of parameters. Thaw penetration into an ice-rich layer at the base of the active layer is accompanied by loss of volume (thaw consolidation) and results in subsidence at the ground surface. Differential thaw settlement occurs annually in permafrost environments as the layer of annual thaw (the active layer) develops. Significant ice segregation can occur at the bottom of the active layer during "cold" periods, due predominantly to freezing from below in the autumn and winter. This study examines trends in seasonal thawing of soils and vertical movements of the ground surface associated with formation and ablation of ice near the permafrost table in the Barrow region. The core thaw depth data set consists of ALT measurements conducted under the Circumpolar Active Layer Monitoring (CALM) program. The Barrow CALM site, represented by a regular 1 km2 grid, was established in the early 1990s. The reported ALT observations were initiated in 1992 and are measured annually in late August. Additional ALT measurements are available from a series of 10 x 10 meter plots established in 1962 as part of the Cold Regions Research and Engineering Laboratory (CRREL) research program at Barrow. Annual observations were made between 1962 and 1970. Measurements were reestablished in 1991 under the CALM program, following the original methodology. Field investigations to track interannual vertical movements associated with formation and ablation of ice near the permafrost table were initiated in 2003. Measurements continue annually at several CRREL plots representative of different elements of the tundra landscape. Observations were made at the end of the thawing season using Differential Global Positioning Systems (DGPS) technology. Results from data analysis indicate that long-term changes in ALT are accompanied by pronounced interannual variability. No significant trends are observed in the active-layer record over the last 20 years. The values from the 1960s are generally higher than in the 1990s and are very similar to those of the 2000s. Following below-average thaw in 1991-1993, there was a general increase in ALT, followed by stabilization in the thawing regime during 1999-2011. The sampled areas showed net subsidence of the ground surface over the period of observation (2003-2011), reducing average surface elevation by 0.13 m. To evaluate the integrated thermal response of this permafrost landscape to climatic forcing, site-average annual thaw depth values were correlated with the square root of DDT, estimated from site-specific air temperature records and accumulated by the date of thaw depth and surface elevation measurements. The linear best-fit regression equation was used, in conjunction with the DDT record, to estimate the vertical position of the ground surface years prior to 2003, when DGPS surveys were initiated. Results indicate that over the 18 year period the elevation of the permafrost table has decreased by 0.33 m. Only 36% (0.12 m) of this change is attributable to increased active-layer thickness, while 64% (0.21m) is attributable to subsidence of the ground surface.

Shiklomanov, N. I.; Streletskiy, D. A.; Nelson, F. E.

2012-12-01

289

Short and Long-Term Effects of Deltamethrin on Filtering Activity of Freshwater Mussel ( Anodonta cygneaL.)  

Microsoft Academic Search

Bioindicator methods were used to study the effects of the pyrethroid insecticide deltamethrin on the filtering behavior of the freshwater musselAnodonta cygneaL in the laboratory, during short-term (30 min) and long-term (1 week) exposure. In the course of the short-term treatment, the water flow through the outflow syphon was monitored. It was found that 1 and 5 ?g\\/liter deltamethrin caused

Cs. Kontreczky; A. Farkas; J. Nemcsók; J. Salánki

1997-01-01

290

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.

Das, Laxmidhar; Vinayak, Manjula

2014-01-01

291

Baroreflex activation therapy provides durable benefit in patients with resistant hypertension: results of long-term follow-up in the Rheos Pivotal Trial.  

PubMed

The objective of this study was to assess long-term blood pressure control in resistant hypertension patients receiving baroreflex activation therapy (BAT). Following completion of the randomized Rheos Pivotal Trial, patients participated in open-label, nonrandomized follow-up to assess safety and efficacy of BAT. Blood pressure reductions were measured relative to a pre-implant baseline as well as the results achieved at the completion of 1 year of follow-up in the randomized phase. Clinically significant responder status was assessed according to FDA-mandated criteria. Of the 322 patients implanted, 76% (n = 245) qualified as clinically significant responders, an additional 10% were indeterminate. Among long-term responders receiving BAT, the mean blood pressure drop was 35/16 mm Hg. Medication use was reduced by the end of the randomized phase and remained lower through the follow-up period. Among responders, 55% achieved goal blood pressures (<140 mm Hg or <130 mm Hg in diabetes or kidney disease). Blood pressures of all active patients remained stable from completion of the randomized phase through long-term follow-up. BAT substantially reduced arterial pressure for most patients participating in the Rheos Pivotal Trial. This blood pressure reduction or goal achievement was maintained over long-term follow-up of 22 to 53 months. PMID:22341199

Bakris, George L; Nadim, Mitra K; Haller, Hermann; Lovett, Eric G; Schafer, Jill E; Bisognano, John D

2012-01-01

292

Long-term therapy of chronic non-malignant pain with potent opioids in an active police officer  

Microsoft Academic Search

Purpose  To report the successful long-term use of methadone and tramadol in treating low back pain in a marine police officer.\\u000a \\u000a \\u000a \\u000a Principal findings  The patient sustained a work-related injury having fallen down stairs while on duty in 1990. After multiple operations for\\u000a a prolapsed L5\\/S 1 intervertebral disk, he was first seen at our pain clinic in 1994. Numerous systemic medications, invasive

Peter H. K. Mak; Siu L. Tsui; K. F. Jacobus Ng

2002-01-01

293

Hepatic monooxygenase (CYP1A and CYP3A) and UDPGT enzymatic activities as biomarkers for long-term carbofuran exposure in tench (Tinca tinca L)  

Microsoft Academic Search

The effect of a long-term exposure of tenchs to different concentrations (10 and 100 ? g\\/L) of the pesticide carbofuran has been evaluated. Microsomal hepatic cytochrome P450 subfamily 1A (CYP1A) and 3A (CYP3A) activities, as well as the phase II enzyme uridine diphospho-glucuronosyltransferase (UDPGT) activity were evaluated as adequate biomarkers of fish exposure to environmentally relevant concentrations of the pesticide

David Hernández-Moreno; Francisco Soler-Rodríguez; M. Prado Míguez-Santiyán; Marcos Pérez-López

2008-01-01

294

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

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

295

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

296

Effects of activation and inhibition of cAMP-dependent protein kinase on long-term habituation in the crab Chasmagnathus  

Microsoft Academic Search

On sudden presentation of a danger stimulus, the crabChasmagnathus elicits an escape response that habituates promptly and for a long period. We have previously reported that administration of a CAMP-permeable analog (CPT-CAMP) along with a phosphodiesterase inhibitor (IBMX) improves long-term habituation (LTH). In present experiments we studied the effect of systemic administration of the protein kinase A (PKA) activator Sp-5,6-DCI-cBIMPS

Arturo Romano; Fernando Locatelli; Alejandro Delorenzi; Maria E. Pedreira; Hector Maldonado

1996-01-01

297

Synaptic Long-Term Potentiation and Depression in the Rat Medial Vestibular Nuclei Depend on Neural Activation of Estrogenic and Androgenic Signals  

PubMed Central

Estrogenic and androgenic steroids can be synthesised in the brain and rapidly modulate synaptic transmission and plasticity through direct interaction with membrane receptors for estrogens (ERs) and androgens (ARs). We used whole cell patch clamp recordings in brainstem slices of male rats to explore the influence of ER and AR activation and local synthesis of 17?-estradiol (E2) and 5?-dihydrotestosterone (DHT) on the long-term synaptic changes induced in the neurons of the medial vestibular nucleus (MVN). Long-term depression (LTD) and long-term potentiation (LTP) caused by different patterns of high frequency stimulation (HFS) of the primary vestibular afferents were assayed under the blockade of ARs and ERs or in the presence of inhibitors for enzymes synthesizing DHT (5?-reductase) and E2 (P450-aromatase) from testosterone (T). We found that LTD is mediated by interaction of locally produced androgens with ARs and LTP by interaction of locally synthesized E2 with ERs. In fact, the AR block with flutamide prevented LTD while did not affect LTP, and the blockade of ERs with ICI 182,780 abolished LTP without influencing LTD. Moreover, the block of P450-aromatase with letrozole not only prevented the LTP induction, but inverted LTP into LTD. This LTD is likely due to the local activation of androgens, since it was abolished under blockade of ARs. Conversely, LTD was still induced in the presence of finasteride the inhibitor of 5?-reductase demonstrating that T is able to activate ARs and induce LTD even when DHT is not synthesized. This study demonstrates a key and opposite role of sex neurosteroids in the long-term synaptic changes of the MVN with a specific role of T-DHT for LTD and of E2 for LTP. Moreover, it suggests that different stimulation patterns can lead to LTD or LTP by specifically activating the enzymes involved in the synthesis of androgenic or estrogenic neurosteroids.

Scarduzio, Mariangela; Panichi, Roberto; Pettorossi, Vito Enrico; Grassi, Silvarosa

2013-01-01

298

Amyloid-Mediated Inhibition of NMDA Receptor-Dependent Long-Term Potentiation Induction Involves Activation of Microglia and Stimulation of Inducible Nitric Oxide Synthase and Superoxide  

Microsoft Academic Search

The mechanisms underlying the inhibition of long-term potentiation (LTP) induction by amyloid-peptide (A) were investigated in the medial perforant path of the rat and mouse dentate gyrus in vitro. Evidence is presented in this study that the A-mediated inhibition of LTP induction involves activation of microglia and production of reactive oxygen and nitrogen species. In control slices, A strongly inhibited

Qinwen Wang; Michael J. Rowan; Roger Anwyl

2004-01-01

299

Effects on glucose homeostasis and insulin secretion of long term activation of the glucose-dependent insulinotropic polypeptide (GIP) receptor by N-AcGIP(LysPAL  

Microsoft Academic Search

Glucose-dependent insulinotropic polypeptide (GIP) is a key hormone of the enteroinsular axis. The present study was designed to assess the metabolic effects in healthy mice of long term activation of the GIP receptor by N-AcGIP(LysPAL37), a potent long-acting GIP receptor agonist. Daily injection of N-AcGIP(LysPAL37) (25 nmol\\/kg body weight) for 14 days had no significant effect on food intake, body

Nigel Irwin; Brian D. Green; Victor A. Gault; Roslyn S. Cassidy; Finbarr P. m. O'harte; Patrick Harriott; Peter R. Flatt

300

An ecological dose-response model approach to short- and long-term effects of heavy metals on arylsulphatase activity in soil  

Microsoft Academic Search

The aim of this study was to provide data to evaluate the short- and long-term effects of heavy metals on arylsulphatase activity in five soils. The effects are fitted on a logistic dose-response model and are presented graphically as the ecological dose (heavy metal concentration corresponding to 50% inhibition; ED50) and ecological dose range (heavy metal concentration range corresponding to

L. Haanstra; P. Doelman

1991-01-01

301

Short and long-term effects of heavy metals on phosphatase activity in soils: An ecological dose-response model approach  

Microsoft Academic Search

The aim of this study was to provide manageable data to help establish permissible limits for the pollution of soil by heavy metals. Therefore the short-and long-term effects of heavy metal pollution on phosphatase activity was studied in five different soil types. The results are presented graphically as logistic dose-response curves. It was possible to construct a curve for sand

P. Doelman; L. Haanstra

1989-01-01

302

Long-term electrophysiological activity and pharmacological response of a human induced pluripotent stem cell-derived neuron and astrocyte co-culture.  

PubMed

Human induced pluripotent stem cell (hiPSC)-derived neurons may be effectively used for drug discovery and cell-based therapy. However, the immaturity of cultured human iPSC-derived neurons and the lack of established functional evaluation methods are problematic. We here used a multi-electrode array (MEA) system to investigate the effects of the co-culture of rat astrocytes with hiPSC-derived neurons on the long-term culture, spontaneous firing activity, and drug responsiveness effects. The co-culture facilitated the long-term culture of hiPSC-derived neurons for >3 months and long-term spontaneous firing activity was also observed. After >3 months of culture, we observed synchronous burst firing activity due to synapse transmission within neuronal networks. Compared with rat neurons, hiPSC-derived neurons required longer time to mature functionally. Furthermore, addition of the synapse antagonists bicuculline and 6-cyano-7-nitroquinoxaline-2,3-dione induced significant changes in the firing rate. In conclusion, we used a MEA system to demonstrate that the co-culture of hiPSC-derived neurons with rat astrocytes is an effective method for studying the function of human neuronal cells, which could be used for drug screening. PMID:24406164

Odawara, A; Saitoh, Y; Alhebshi, A H; Gotoh, M; Suzuki, I

2014-01-24

303

Long-term methionine exposure induces memory impairment on inhibitory avoidance task and alters acetylcholinesterase activity and expression in zebrafish (Danio rerio).  

PubMed

Hypermethioninemic patients exhibit a variable degree of neurological dysfunction. However, the mechanisms involved in these alterations have not been completely clarified. Cholinergic system has been implicated in many physiological processes, including cognitive performances, as learning, and memory. Parameters of cholinergic signaling have already been characterized in zebrafish brain. Since zebrafish is a small freshwater teleost which is a vertebrate model for modeling behavioral and functional parameters related to human pathogenesis and for clinical treatment screenings, in the present study we investigated the effects of short- and long-term methionine exposure on cognitive impairment, AChE activity and gene expression in zebrafish. For the studies, animals were exposed at two methionine concentrations (1.5 and 3.0 mM) during 1 h or 7 days (short- or long-term treatments, respectively). We observed a significant increase in AChE activity of zebrafish brain membranes after long-term methionine exposure at 3.0 mM. However, AChE gene expression decreased significantly in both concentrations tested after 7 days of treatment, suggesting that post-translational events are involved in the enhancement of AChE activity. Methionine treatment induces memory deficit in zebrafish after long-term exposure to this amino acid, which could be related, at least in part, with cognitive impairment observed in hypermethioninemia. Therefore, the results here presented raise a new perspective to use the zebrafish as a complementary vertebrate model for studying inborn errors of metabolism, which may help to better understand the pathophysiology of this disease. PMID:22437435

Vuaden, Fernanda Cenci; Savio, Luiz Eduardo B; Piato, Angelo L; Pereira, Talita C; Vianna, Mônica R; Bogo, Maurício R; Bonan, Carla D; Wyse, Angela T S

2012-07-01

304

Geothermal constraints on the hydrological regime of the TAG active hydrothermal mound, inferred from long-term monitoring  

NASA Astrophysics Data System (ADS)

During August 1994 to March 1995, a period that included ODP Leg 158 drilling, bottom-water and sub-bottom temperatures were continuously logged by a long-term temperature monitoring system 'Daibutsu' at the base of the central black-smoker complex (CBC) and within the low heat flow zone at the TAG hydrothermal mound on the Mid-Atlantic Ridge. The temperature of hydrothermal fluid at CBC was also measured with a small high-temperature probe 'Hobo'. Bottom-water temperature variations measured with Daibutsu at both sites have predominant semi-diurnal periods, causing the sub-bottom temperatures to fluctuate at these periods with reduced amplitudes and phase delays at sub-bottom depths. Seawater entrainment into the mound has been previously suggested at the low heat flow zone. We quantitatively evaluate the seawater entrainment rate at both sites from a one-dimensional numerical model, combined with a heat conduction model for the semi-diurnal variations. The entrainment rate of seawater at the base of CBC is estimated as 1.3±0.5×10 -5 m/s, at least from August 17 to 30, 1994. On the other hand, the seawater entrainment rate at the low heat flow zone was undetected by long-term temperature monitoring at shallow sub-bottom depth. Nevertheless an increase in heat flow observed at the low heat flow zone during ODP drilling can be interpreted as a decrease in the entrainment rate of seawater. Before ODP Leg 158, Daibutsu measured three sub-bottom temperature anomalies at the base of CBC not derived from bottom-water temperature variations and Hobo also detected a CBC fluid temperature anomaly, indicating some natural changes in fluid flow within the mound. Daibutsu and Hobo also measured temperature anomalies during and after drilling at the ODP TAG-1 area. The Hobo temperature anomalies are inferred to have occurred when the cold fluid entrained through the drill holes at TAG-1 site reached or cooled the main fluid path to CBC. The entrained seawater through the drill holes appears to have contributed to dissolution and precipitation of anhydrite within the mound and perhaps affected the local permeability structure inside the mound. The temperature anomalies measured with Daibutsu at the base of CBC may have been induced by the change in the fluid flow pattern as a result of such permeability changes within the mound.

Goto, Shusaku; Kinoshita, Masataka; Matsubayashi, Osamu; Von Herzen, Richard P.

2002-10-01

305

Long-Term Effects of Irrigation with Waste Water on Soil AM Fungi Diversity and Microbial Activities: The Implications for Agro-Ecosystem Resilience  

PubMed Central

The effects of irrigation with treated urban wastewater (WW) on the arbuscular mycorrhizal fungi (AMF) diversity and soil microbial activities were assayed on a long-term basis in a semiarid orange-tree orchard. After 43 years, the soil irrigated with fresh water (FW) had higher AMF diversity than soils irrigated with WW. Microbial activities were significantly higher in the soils irrigated with WW than in those irrigated with FW. Therefore, as no negative effects were observed on crop vitality and productivity, it seems that the ecosystem resilience gave rise to the selection of AMF species better able to thrive in soils with higher microbial activity and, thus, to higher soil fertility.

del Mar Alguacil, Maria; Torrecillas, Emma; Torres, Pilar; Garcia-Orenes, Fuensanta; Roldan, Antonio

2012-01-01

306

Hypocholesterolaemic activity of suloctidil: double-blind, crossover short-term and long-term treatment trial.  

PubMed

Two studies were carried out in patients with primary hyperlipidaemia to investigate the effect of suloctidil (200 mg 3-times daily) on serum cholesterol levels and other lipidaemic variables. The first study was a double-blind, crossover comparison of suloctidil and placebo in 23 patients. Patients were allocated at random to receive one or other treatment for 4 weeks, after a wash-out period of 4 weeks on placebo, and were then crossed over to the alternative medication for the following 4 weeks. Patients were kept on a controlled diet throughout the trial. In the second, long-term study, 28 patients were treated, after an initial washout period of 8 weeks on placebo, with suloctidil for periods of up to 1 year. As in the short-term trial, patients were maintained on a controlled diet. The results showed that suloctidil produced a statistically significant reduction in total serum cholesterol and serum triglycerides in the short-term and this reduction was maintained over the longer period of the second study. In addition, there was a concomitant and approximately proportional increase in HDL-cholesterol. Suloctidil was well tolerated and no serious side-effects were reported. PMID:6094103

Chieffo, C; Postiglione, A; Tritto, C; Mancini, M

1984-01-01

307

[Responses of enzyme activities in different particle-size aggregates of paddy soil in Taihu Lake region of China to long-term fertilization].  

PubMed

Taking a long-term fertilized paddy soil in Taihu Lake region as research object, the enzyme activities in <2, 2-20, 20-200, and 200-2000 microm aggregates under no fertilization (NF), chemical fertilization (CF), chemical fertilization plus straw return (CFS), and chemical fertilization plus pig manure (CFM) were investigated. Fertilization promoted the formation of 200-2000 microm aggregates significantly. The enzyme activities differed with aggregates' particle-size. Urease and invertase activities were the highest in <2 microm aggregates, whereas the activities of cellulase, polyphenoloxidase and FDA hydrolase were the highest in 200-2000 microm aggregates. Fertilization, especially the combined fertilization of inorganic and organic fertilizers, increased the activities of urease, invertase, cellulase and FDA hydrolase in 200-2000 microm aggregates significantly. With the geometric mean (GMea) of the five test enzyme activities as the integrative index of soil enzyme activities, it was found that under fertilization, the GMea was significantly higher in 200-2000 microm aggregates, suggesting the high sensitivity of enzyme activities in larger particle-size aggregates to fertilization practices. Long-term inorganic plus organic fertilization could enhance the soil bio-function via the promotion of the formation of larger particle-size aggregates and the enzyme activities in these aggregates. PMID:20030140

Niu, Wen-jing; Li, Lian-qing; Pan, Gen-xing; Song, Xiang-yun; Li, Zhi-peng; Liu, Xiao-yu; Liu, Yong-zhuo

2009-09-01

308

Insolation data manual: Long-term monthly averages of solar radiation, temperature, degree-days, and global KT for 248 National Weather Service stations and direct normal solar radiation data manual: Long-term, monthly mean, daily totals for 235 National Weather Service stations  

NASA Astrophysics Data System (ADS)

The Insolation Data Manual presents monthly averaged data which describes the availability of solar radiation at 248 National Weather Service (NWS) stations, principally in the United States. Monthly and annual average daily insolation and temperature values have been computed from a base of 24 to 25 years of data, generally from 1952 to 1975, and listed for each location. Insolation values represent monthly average daily totals of global radiation on a horizontal surface and are depicted using the three units of measurement: kJ/sq m per day, Btu/sq ft per day and langleys per day. Average daily maximum, minimum and monthly temperatures are provided for most locations in both Celsius and Fahrenheit. Heating and cooling degree-days were computed relative to a base of 18.3 C (65 F). For each station, global KT (cloudiness index) values were calculated on a monthly and annual basis. Global KT is an index of cloudiness and indicates fractional transmittance of horizontal radiation, from the top of the atmosphere to the earth's surface. The second section of this volume presents long-term monthly and annual averages of direct normal solar radiation for 235 NWS stations, including a discussion of the basic derivation process. This effort is in response to a generally recognized need for reliable direct normal data and the recent availability of 23 years of hourly averages for 235 stations. The relative inaccessibility of these data on microfiche further justifies reproducing at least the long-term averages in a useful format. In addition to a definition of terms and an overview of the ADIPA model, a discussion of model validation results is presented.

1990-07-01

309

Divergent short- and long-term effects of acute stress in object recognition memory are mediated by endogenous opioid system activation.  

PubMed

Acute stress induces short-term object recognition memory impairment and elicits endogenous opioid system activation. The aim of this study was thus to evaluate whether opiate system activation mediates the acute stress-induced object recognition memory changes. Adult male Wistar rats were trained in an object recognition task designed to test both short- and long-term memory. Subjects were randomly assigned to receive an intraperitoneal injection of saline, 1 mg/kg naltrexone or 3 mg/kg naltrexone, four and a half hours before the sample trial. Five minutes after the injection, half the subjects were submitted to movement restraint during four hours while the other half remained in their home cages. Non-stressed subjects receiving saline (control) performed adequately during the short-term memory test, while stressed subjects receiving saline displayed impaired performance. Naltrexone prevented such deleterious effect, in spite of the fact that it had no intrinsic effect on short-term object recognition memory. Stressed subjects receiving saline and non-stressed subjects receiving naltrexone performed adequately during the long-term memory test; however, control subjects as well as stressed subjects receiving a high dose of naltrexone performed poorly. Control subjects' dissociated performance during both memory tests suggests that the short-term memory test induced a retroactive interference effect mediated through light opioid system activation; such effect was prevented either by low dose naltrexone administration or by strongly activating the opioid system through acute stress. Both short-term memory retrieval impairment and long-term memory improvement observed in stressed subjects may have been mediated through strong opioid system activation, since they were prevented by high dose naltrexone administration. Therefore, the activation of the opioid system plays a dual modulating role in object recognition memory. PMID:24036398

Nava-Mesa, Mauricio O; Lamprea, Marisol R; Múnera, Alejandro

2013-11-01

310

Enhanced hippocampal long-term potentiation and learning by increased neuronal expression of tissue-type plasminogen activator in transgenic mice.  

PubMed Central

Adult cortical neurons can produce tissue-type plasminogen activator (tPA), an extracellular protease that plays a critical role in fibrinolysis and tissue remodelling processes. There is growing evidence that extracellular proteolysis may be involved in synaptic plasticity, axonal remodelling and neurotoxicity in the adult central nervous system. Here we show that transgenic mice overexpressing tPA in post-natal neurons have increased and prolonged hippocampal long-term potentiation (LTP), and improved performance in spatial orientation learning tasks. Extracellular proteolysis catalysed by tPA may facilitate synaptic micro-remodelling, and thereby play a role in activity-dependent neuronal plasticity and learning.

Madani, R; Hulo, S; Toni, N; Madani, H; Steimer, T; Muller, D; Vassalli, J D

1999-01-01

311

Long-term decline of South Pole neutron rates  

Microsoft Academic Search

The count rate recorded by a neutron monitor at South Pole, Antarctica, displays a long-term decline over the 32-year span from 1965 to 1997. The neutron rate follows an 11-year cycle with maxima at times of low solar activity, but the 1997 peak rate was approximately 8% lower than the 1965 peak rate based on 27-d averages. This change is

J. W. Bieber; J. Clem; D. Desilets; P. Evenson; D. Lal; C. Lopate; R. Pyle

2007-01-01

312

Long-Term Decline of South Pole Neutron Rate  

Microsoft Academic Search

The count rate recorded by a neutron monitor at South Pole, Antarctica displays a long-term decline over the 22-year span from 1965 to 1987. The neutron rate follows an 11-year cycle with maxima at times of low solar activity, but the 1987 peak rate was approximately 9% lower than the 1965 peak rate based on 27-day averages. This change is

J. W. Bieber; J. Clem; P. Evenson; R. Pyle; D. Lal; D. Desilets; C. Lopate

2003-01-01

313

Long-term association between leisure-time physical activity and changes in happiness: analysis of the Prospective National Population Health Survey.  

PubMed

Happiness is among the most fundamental of all human goals. Although the short-term association between physical activity and happiness is well known, the long-term associations are not. Data from the National Population Health Survey cycles conducted between 1994/1995 and 2008/2009 (cycles 1 through 8) were analyzed. Happy respondents were classified as physically active or inactive at baseline and then were followed up in subsequent cycles to examine their likelihood of becoming unhappy. Individuals who changed their activity level also were examined. After controlling for potential confounding factors, the authors found that leisure-time physical activity (LTPA) was associated with reduced odds of unhappiness after 2 years and 4 years. People who were inactive in 2 consecutive cycles were more than twice as likely to be unhappy as those who remained active in both cycles after 2 years. Compared with those who became active, inactive participants who remained inactive were also more likely to become unhappy. A change in LTPA from active to inactive was associated with increased odds of becoming unhappy 2 years later. This study suggests that LTPA has a long-term association with happiness. Changes in LTPA are associated with subsequent mood status. PMID:23171884

Wang, Feng; Orpana, Heather M; Morrison, Howard; de Groh, Margaret; Dai, Sulan; Luo, Wei

2012-12-15

314

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.

2014-01-01

315

Long-term changes in the Coulomb failure function on inland active faults in southwest Japan due to east-west compression and interplate earthquakes  

NASA Astrophysics Data System (ADS)

earthquake activity in and around the Kinki region, southwest Japan, increases in the period from several decades before to about a decade after the occurrence of great interplate earthquakes along the Nankai Trough. To quantitatively investigate this relationship, we calculated long-term changes in the Coulomb failure function (?CFF) on inland active faults in this region with viscoelastic slip response functions. As sources for the change in CFF, we investigated east-west compression within the Niigata-Kobe Tectonic Zone (NKTZ), historical interplate earthquakes and interseismic locking along the Nankai Trough subduction zone, and historical inland earthquakes in this region. Among these sources, the NKTZ east-west compression is the primary cause of the long-term changes in CFF. The changes in CFF due to interplate earthquakes are mostly negative on reverse faults and positive on strike-slip faults. This result suggests that the inland reverse faulting activity mostly increases before interplate earthquakes and decreases after the earthquakes, whereas strike-slip activity is mostly suppressed before interplate earthquakes and increases thereafter. This suggestion is supported by spatiotemporal pattern of historical inland earthquakes if focal mechanisms of historical earthquakes correspond to fault geometries in the region. The calculated changes in CFF are usually consistent with the occurrence of historical inland earthquakes. If we use the change in shear stress instead of the change in CFF, this consistency is enhanced, which suggests low apparent coefficients of friction in this region.

Shikakura, Yosuke; Fukahata, Yukitoshi; Hirahara, Kazuro

2014-01-01

316

Long-term ?1B-adrenergic receptor activation shortens lifespan, while ?1A-adrenergic receptor stimulation prolongs lifespan in association with decreased cancer incidence.  

PubMed

The ?1-adrenergic receptor (?1AR) subtypes, ?1AAR and ?1BAR, have differential effects in the heart and central nervous system. Long-term stimulation of the ?1AAR subtype prolongs lifespan and provides cardio- and neuro-protective effects. We examined the lifespan of constitutively active mutant (CAM)-?1BAR mice and the incidence of cancer in mice expressing the CAM form of either the ?1AAR (CAM-?1AAR mice) or ?1BAR. CAM-?1BAR mice have a significantly shortened lifespan when compared with wild-type (WT) animals; however, the effect was sex dependent. Female CAM-?1BAR mice lived significantly shorter lives, while the median lifespan of male CAM-?1BAR mice was not different when compared with that of WT animals. There was no difference in the incidence of cancer in either sex of CAM-?1BAR mice. The incidence of cancer was significantly decreased in CAM-?1AAR mice when compared with that in WT, and no sex-dependent effects were observed. Further study is warranted on cancer incidence after activation of each ?1AR subtype and the effect of sex on lifespan following activation of the ?1BAR. The implications of a decrease in cancer incidence following long-term ?1AAR stimulation could lead to improved treatments for cancer. PMID:24994537

Collette, Katie M; Zhou, Xu Dong; Amoth, Haley M; Lyons, Mariaha J; Papay, Robert S; Sens, Donald A; Perez, Dianne M; Doze, Van A

2014-08-01

317

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.

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

2012-01-01

318

Long-term effects of 4-year longitudinal school-based physical activity intervention on the physical fitness of children and youth during 7-year followup assessment.  

PubMed

Many school-based physical activity (PA) interventions have been developed, but only a few have assessed their long-term effects. A PA intervention taking place in the first four years of some Slovenian primary schools entails an enhanced physical education (PE) curriculum, including two extra lessons of PE per week, a wider selection of PE content, and additional outdoor education delivered by both a specialist PE teacher and a general teacher. The effects of the intervention on children's physical fitness (motor tasks and anthropometry) were evaluated within a quasi-experimental study. In total, 324 children from nine Slovenian primary schools either received the enhanced curriculum (intervention (n=160)) or standard PE (control (n=164)), and were followed for a four-year intervention period and seven years post intervention. Data from the SLOFIT database were used to compare differences in the physical fitness of children each year. Linear Mixed Models were used to test the influence of the PA intervention. Over an 11-year period, the PA intervention group significantly differed in all motor tasks, but not in anthropometric measures or body mass index, after controlling for year of measurement and sex. Differences between the control and intervention groups decreased with time. This study highlights the importance of tracking the long term effects of PA interventions. PA intervention in the first four years of Slovenian primary school offers the possibility of improving physical performance in children; initiatives aiming to increase their performance (physical fitness, physical activity) and health outcomes are warranted. PMID:24592722

Jurak, Gregor; Cooper, Ashley; Leskosek, Bojan; Kovac, Marjeta

2013-12-01

319

Long-term inhibition of protein tyrosine kinase impairs electrophysiologic activity and a rapid component of exocytosis in pancreatic  -cells  

Microsoft Academic Search

Dysfunction of pancreatic -cells is a fundamental feature in the pathogenesis of type 2 diabetes. As insulin receptor signaling occurs via protein tyrosine kinase (PTK), we investigated the role of PTK activity in the etiology of -cell dysfunction by inhibiting PTK activity in primary cultured mouse pancreatic -cells and INS-1 cells with genistein treatment over 24 h. Electrophysiologic recordings showed

Yu-Feng Zhao; Damien J Keating; Maria Hernandez; Dan Dan Feng; Yulong Zhu; Chen Chen

2005-01-01

320

Long-term effects of a playground markings and physical structures on children's recess physical activity levels  

Microsoft Academic Search

Objective.The aim of the study was to investigate the impact of a playground redesign intervention across time on children's recess physical activity levels using combined physical activity measures and to evaluate the potential influence of covariates on the intervention effect.

Nicola D. Ridgers; Gareth Stratton; Stuart J. Fairclough; Jos W. R. Twisk

2007-01-01

321

Long-term effects of heavy metals from composted municipal waste on some enzyme activities in a cultivated soil  

Microsoft Academic Search

A 3-year field experiment on a calcareous Fluventic Xerochrept planted with corn (Zea mays L.) was carried out to evaluate the effects of amending the soil with high and low rates of composted municipal waste on soil enzyme activities (alkaline phosphomonoesterase, phosphodiesterase, arylsulphatase, dehydrogenase, and l-asparaginase). These enzyme activities all increased when compost was added at rates of up to

Daniela Businelli; Pier Lodovico Giusquiani; Giovanni Gigliotti

1994-01-01

322

Long-term Pharmacological Activation of PPAR?Does not Prevent Left Ventricular Remodeling in Dogs with Advanced Heart Failure  

Microsoft Academic Search

Background  Peroxisome proliferator-activated receptor ? (PPAR?) activators affect the myocardium through inhibition of inflammatory cytokines\\u000a and metabolic modulation but their effect in the progression of heart failure is unclear. In the present study, we examined\\u000a the effects of the PPAR? activator, GW347845 (GW), on the progression of heart failure.\\u000a \\u000a \\u000a \\u000a Methods and results  Heart failure was produced in 21 dogs by intracoronary microembolizations

George Suzuki; Sanjaya Khanal; Sharad Rastogi; Hideaki Morita; Takayuki Mishima; Petros V. Anagnostopoulos; Omar Nass; Victor G. Sharov; Elaine J. Tanhehco; Sidney Goldstein; Hani N. Sabbah

2007-01-01

323

Recurrent laryngeal nerve activity exhibits a 5-HT-mediated long-term facilitation and enhanced response to hypoxia following acute intermittent hypoxia in rat.  

PubMed

A progressive and sustained increase in inspiratory-related motor output ("long-term facilitation") and an augmented ventilatory response to hypoxia occur following acute intermittent hypoxia (AIH). To date, acute plasticity in respiratory motor outputs active in the postinspiratory and expiratory phases has not been studied. The recurrent laryngeal nerve (RLN) innervates laryngeal abductor muscles that widen the glottic aperture during inspiration. Other efferent fibers in the RLN innervate adductor muscles that partially narrow the glottic aperture during postinspiration. The aim of this study was to investigate whether or not AIH elicits a serotonin-mediated long-term facilitation of laryngeal abductor muscles, and if recruitment of adductor muscle activity occurs following AIH. Urethane anesthetized, paralyzed, unilaterally vagotomized, and artificially ventilated adult male Sprague-Dawley rats were subjected to 10 exposures of hypoxia (10% O(2) in N(2), 45 s, separated by 5 min, n = 7). At 60 min post-AIH, phrenic nerve activity and inspiratory RLN activity were elevated (39 ± 11 and 23 ± 6% above baseline, respectively). These responses were abolished by pretreatment with the serotonin-receptor antagonist, methysergide (n = 4). No increase occurred in time control animals (n = 7). Animals that did not exhibit postinspiratory RLN activity at baseline did not show recruitment of this activity post-AIH (n = 6). A repeat hypoxia 60 min after AIH produced a significantly greater peak response in both phrenic and RLN activity, accompanied by a prolonged recovery time that was also prevented by pretreatment with methysergide. We conclude that AIH induces neural plasticity in laryngeal motoneurons, via serotonin-mediated mechanisms similar to that observed in phrenic motoneurons: the so-called "Q-pathway". We also provide evidence that the augmented responsiveness to repeat hypoxia following AIH also involves a serotonergic mechanism. PMID:22241052

Bautista, Tara G; Xing, Tao; Fong, Angelina Y; Pilowsky, Paul M

2012-04-01

324

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.

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

2011-01-01

325

Validation of long-term primary neuronal cultures and network activity through the integration of reversibly bonded microbioreactors and MEA substrates.  

PubMed

In vitro recording of neuronal electrical activity is a widely used technique to understand brain functions and to study the effect of drugs on the central nervous system. The integration of microfluidic devices with microelectrode arrays (MEAs) enables the recording of networks activity in a controlled microenvironment. In this work, an integrated microfluidic system for neuronal cultures was developed, reversibly coupling a PDMS microfluidic device with a commercial flat MEA through magnetic forces. Neurons from mouse embryos were cultured in a 100 µm channel and their activity was followed up to 18 days in vitro. The maturation of the networks and their morphological and functional characteristics were comparable with those of networks cultured in macro-environments and described in literature. In this work, we successfully demonstrated the ability of long-term culturing of primary neuronal cells in a reversible bonded microfluidic device (based on magnetism) that will be fundamental for neuropharmacological studies. PMID:21858786

Biffi, Emilia; Menegon, Andrea; Piraino, Francesco; Pedrocchi, Alessandra; Fiore, Gianfranco B; Rasponi, Marco

2012-01-01

326

Long-Term Exposure to Concentrated Ambient PM2.5 Increases Mouse Blood Pressure through Abnormal Activation of the Sympathetic Nervous System: A Role for Hypothalamic Inflammation  

PubMed Central

Background: Exposure to particulate matter ? 2.5 ?m in diameter (PM2.5) increases blood pressure (BP) in humans and animal models. Abnormal activation of the sympathetic nervous system may have a role in the acute BP response to PM2.5 exposure. The mechanisms responsible for sympathetic nervous system activation and its role in chronic sustenance of hypertension in response to PM2.5 exposure are currently unknown. Objectives: We investigated whether central nervous system inflammation may be implicated in chronic PM2.5 exposure-induced increases in BP and sympathetic nervous system activation. Methods: C57BL/6J mice were exposed to concentrated ambient PM2.5 (CAPs) for 6 months, and we analyzed BP using radioactive telemetric transmitters. We assessed sympathetic tone by measuring low-frequency BP variability (LF-BPV) and urinary norepinephrine excretion. We also tested the effects of acute pharmacologic inhibitors of the sympathetic nervous system and parasympathetic nervous system. Results: Long-term CAPs exposure significantly increased basal BP, paralleled by increases in LF-BPV and urinary norepinephrine excretion. The increased basal BP was attenuated by the centrally acting ?2a agonist guanfacine, suggesting a role of increased sympathetic tone in CAPs exposure–induced hypertension. The increase in sympathetic tone was accompanied by an inflammatory response in the arcuate nucleus of the hypothalamus, evidenced by increased expression of pro-inflammatory genes and inhibitor kappaB kinase (IKK)/nuclear factor–kappaB (NF-?B) pathway activation. Conclusion: Long-term CAPs exposure increases BP through sympathetic nervous system activation, which may involve hypothalamic inflammation. Citation: Ying Z, Xu X, Bai Y, Zhong J, Chen M, Liang Y, Zhao J, Liu D, Morishita M, Sun Q, Spino C, Brook RD, Harkema JR, Rajagopalan S. 2014. Long-term exposure to concentrated ambient PM2.5 increases mouse blood pressure through abnormal activation of the sympathetic nervous system: a role for hypothalamic inflammation. Environ Health Perspect 122:79–86;?http://dx.doi.org/10.1289/ehp.1307151

Xu, Xiaohua; Bai, Yuntao; Zhong, Jixin; Chen, Minjie; Liang, Yijia; Zhao, Jinzhuo; Liu, Dongyao; Morishita, Masako; Sun, Qinghua; Spino, Catherine; Brook, Robert D.; Harkema, Jack R.; Rajagopalan, Sanjay

2013-01-01

327

Long-term plasticity in the regulation of olfactory bulb activity by centrifugal fibers from piriform cortex.  

PubMed

Olfactory bulb granule cells are activated synaptically via two main pathways. Mitral/tufted (M/T) cells form dendrodendritic synapses on granule cells that can be activated by antidromic stimulation of the lateral olfactory tract (LOT). Centrifugal fibers originating from the association fiber (AF) system in piriform cortex (PC) make axodendritic synapses on granule cells within the granule cell layer (GCL) that can be activated by orthodromic stimulation of AF axons in the PC. We explored functional plasticity in the AF pathway by recording extracellularly from individual M/T cells and presumed granule cells in male Long-Evans rats under urethane anesthesia while testing their response to LOT and AF stimulation. Presumed granule cells driven synaptically by LOT stimulation (type L cells) were concentrated in the superficial half of the GCL and were activated at short latencies, whereas those driven synaptically by AF stimulation (type A cells) were concentrated in the deep half of the GCL and were activated at longer latencies. Type A cells were readily detected only in animals in which the AF input to the GCL had been previously potentiated by repeated high-frequency stimulation. An additional bout of high-frequency stimulation administered under urethane caused an immediate increase in the number of action potentials evoked in type A cells by AF test stimulation and a concomitant increase in inhibition of M/T cells. These results underscore the importance of the role played in olfactory processing by PC regulation of OB activity and document the long-lasting potentiation of that regulation by repeated high-frequency AF activation. PMID:25031407

Cauthron, Joy L; Stripling, Jeffrey S

2014-07-16

328

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

329

Reduction in denitrification activity in field soils exposed to long term contamination by 2,4,6-trinitrotoluene (TNT).  

PubMed

Terrestrial sites contaminated with 2,4,6-trinitrotoluene (TNT) are a widespread and persistent problem and often contain non-vegetated areas with TNT concentrations well in excess of 1000 mg kg(-1). In this study, we examined the effect of TNT on denitrification activity in field soils, and compared the sensitivity of denitrifying enzymes to TNT. DNA probes assessed the prevalence of nirS, nirK and nosZ (encoding cd(1) or copper nitrite reductase and nitrous oxide reductase, respectively), denitrifying genotypes in the culturable and total microbial community. The nitrate (NaR), nitrite (NiR) and nitrous oxide (N(2)OR) reductase activities in field soil and in isolates were assessed by gas chromatography. The relative occurrence of the nirK, nirS or nosZ genotypes increased in the cultured community and in total uncultured community DNA as nitroaromatic concentrations increased. However, denitrifying activity decreased in response to increasing TNT concentrations, with an IC(50) for NaR+NiR+nitric oxide reductase (NOR) of 400 mg TNT kg(-1) soil and for N(2)OR of 26 mg TNT kg(-1) soil. The denitrifying activity of four soil isolates also decreased in response to TNT, with N(2)OR activity being three times more sensitive to TNT than NaR+NiR+NOR activity. Interestingly, there were 118 times more nirK isolates than nirS isolates in uncontaminated soil but only 1.5 times more in soil containing 17400 mg kg(-1) TNT. The results from this study indicated that TNT reduced denitrification activity in field soils, and N(2)OR was much more sensitive to TNT than NaR+NiR+NOR. PMID:10779620

Siciliano; Roy; Greer

2000-04-01

330

Retrovirus gene therapy for X-linked chronic granulomatous disease can achieve stable long-term correction of oxidase activity in peripheral blood neutrophils  

PubMed Central

Chronic granulomatous disease (CGD) is associated with significant morbidity and mortality from infection. The first CGD gene therapy trial resulted in only short-term marking of 0.01% to 0.1% of neutrophils. A recent study, using busulfan conditioning and an SFFV retrovirus vector, achieved more than 20% marking in 2 patients with X-linked CGD. However, oxidase correction per marked neutrophil was less than normal and not sustained. Despite this, patients clearly benefited in that severe infections resolved. As such, we initiated a gene therapy trial for X-CGD to treat severe infections unresponsive to conventional therapy. We treated 3 adult patients using busulfan conditioning and an MFGS retroviral vector encoding gp91phox, achieving early marking of 26%, 5%, and 4% of neutrophils, respectively, with sustained long-term marking of 1.1% and 0.03% of neutrophils in 2 of the patients. Gene-marked neutrophils have sustained full correction of oxidase activity for 34 and 11 months, respectively, with full or partial resolution of infection in those 2 patients. Gene marking is polyclonal with no clonal dominance. We conclude that busulfan conditioning together with an MFGS vector is capable of achieving long-term correction of neutrophil oxidase function sufficient to provide benefit in management of severe infection. This study was registered at www.clinicaltrials.gov as #NCT00394316.

Choi, Uimook; Theobald, Narda; Linton, Gilda; Long Priel, Debra A.; Kuhns, Doug; Malech, Harry L.

2010-01-01

331

Long-term down-regulation of EGF-dependent tyrosine kinase activity in PC12 cells  

SciTech Connect

PC12 rat pheochromocytoma cells display cell surface receptors for both nerve growth factor (NGF) and epidermal growth factor (EGF), thus providing a model system with which to study their roles in the regulation of proliferation and differentiation. They have shown that treatment of the cells with NGF induces a progressive decrease (60-90%) in EGF receptors as monitored by (/sup 125/I)EGF binding and crosslinking. In the present report they determine EGF receptor levels in membranes from control and NGF-differentiated PC12 cells by monitoring EGF-receptor kinase activity. Measuring either the phosphorylation of a src-related synthetic peptide or the autophosphorylation of the receptor itself they found specific and maximal stimulation by 10 ng/ml EGF, but not by insulin, NGF, or cytochrome C, a complete dependency on Mn/sup 2 +/ ions, and higher specific activity in the presence of sodium vanadate. Alkaline treatment of the autophosphorylated receptor indicates that 75% of the /sup 32/P is associated with tyrosine residues. Membranes from NGF-differentiated cells show a decrease of 60-80% and 85-95% in the tyrosine kinase activity for exogenous substrate or receptor autophosphorylation, respectively. The possibility that the low levels of EGF-dependent tyrosine kinase activity in differentiated PC12 cells is an expression of a decrease in EGF receptor numbers and/or modulation of their catalytic activity by other kinases is under investigation.

Lazarovici, P.; Kuzuya, H.; Dickens, G.; Guroff, G.

1986-05-01

332

Long-term degradation of resin-based cements in substances present in the oral environment: influence of activation mode  

PubMed Central

Indirect restorations in contact with free gingival margins or principally within the gingival sulcus, where the presence of organic acids produced by oral biofilm is higher, may present faster degradation of the resin-based cement pellicle. Objectives: To investigate the degradation of four resin-based cements: Rely X ARC (R), Variolink II (V), enforce (E) and All Cem (A), after immersion in distilled water (DW), lactic acid (LA) and artificial saliva (AS) and to analyze the influence of the activation mode on this response. Material and Methods: Two activation modes were evaluated: chemical (Ch) and dual (D). In the dual activation, a two-millimeter thick ceramic disk (IPS empress System) was interposed between the specimen and light-curing unit tip. Specimens were desiccated, immersed in distilled water, artificial saliva and lactic acid 0.1 M at 37ºC for 180 days, weighed daily for the first 7 days, and after 14, 21, 28, 90 and 180 days and were desiccated again. Sorption and solubility (µg/mm3) were calculated based on ISO 4049. The data were submitted to multifactor analysis of variance (MANOVA) and Tukey's HSD test for media comparisons (?=0.05). Results: Sorption was higher after immersion in LA (p<0.05) and increased significantly with time (p<0.05). Sorption was influenced by the activation mode: Ch>D (p<0.05). The lowest solubility was presented by R (p<0.05). Conclusions: Lactic acid increased the degradation of resin-based cements. Moreover, the physical component of activation, i.e., light-activation, contributed to a low degradation of resin-based cements.

da SILVA, Eduardo Moreira; NORONHA-FILHO, Jaime Dutra; AMARAL, Cristiane Mariote; POSKUS, Laiza Tatiana; GUIMARAES, Jose Guilherme Antunes

2013-01-01

333

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

334

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

335

Presynaptic long-term plasticity  

PubMed Central

Long-term synaptic plasticity is a major cellular substrate for learning, memory, and behavioral adaptation. Although early examples of long-term synaptic plasticity described a mechanism by which postsynaptic signal transduction was potentiated, it is now apparent that there is a vast array of mechanisms for long-term synaptic plasticity that involve modifications to either or both the presynaptic terminal and postsynaptic site. In this article, we discuss current and evolving approaches to identify presynaptic mechanisms as well as discuss their limitations. We next provide examples of the diverse circuits in which presynaptic forms of long-term synaptic plasticity have been described and discuss the potential contribution this form of plasticity might add to circuit function. Finally, we examine the present evidence for the molecular pathways and cellular events underlying presynaptic long-term synaptic plasticity.

Yang, Ying; Calakos, Nicole

2013-01-01

336

Admission Lipoprotein-Associated Phospholipase A2 Activity Is Not Associated with Long-Term Clinical Outcomes after ST-Segment Elevation Myocardial Infarction  

PubMed Central

Background Lipoprotein-associated phospholipase A2 (Lp-PLA2) activity is a biomarker predicting cardiovascular diseases in a real-world. However, the prognostic value in patients undergoing primary percutaneous coronary intervention (pPCI) for ST-segment elevation myocardial infarction (STEMI) on long-term clinical outcomes is unknown. Methods Lp-PLA2 activity was measured in samples obtained prior to pPCI from consecutive STEMI patients in a high-volume intervention center from 2005 until 2007. Five years all-cause mortality was estimated with the Kaplan-Meier method and compared among tertiles of Lp-PLA2 activity during complete follow-up and with a landmark at 30 days. In a subpopulation clinical endpoints were assessed at three years. The prognostic value of Lp-PLA2, in addition to the Thrombolysis In Myocardial Infarction or multimarker risk score, was assessed in multivariable Cox regression. Results The cohort (n?=?987) was divided into tertiles (low <144, intermediate 144–179, and high >179 nmol/min/mL). Among the tertiles differences in baseline characteristics associated with long-term mortality were observed. However, no significant differences in five years mortality in association with Lp-PLA2 activity levels were found; intermediate versus low Lp-PLA2 (HR 0.97; CI 95% 0.68–1.40; p?=?0.88) or high versus low Lp-PLA2 (HR 0.75; CI 95% 0.51–1.11; p?=?0.15). Both in a landmark analysis and after adjustments for the established risk scores and selection of cases with biomarkers obtained, non-significant differences among the tertiles were observed. In the subpopulation no significant differences in clinical endpoints were observed among the tertiles. Conclusion Lp-PLA2 activity levels at admission prior to pPCI in STEMI patients are not associated with the incidence of short and/or long-term clinical endpoints. Lp-PLA2 as an independent and clinically useful biomarker in the risk stratification of STEMI patients still remains to be proven.

Woudstra, Pier; Damman, Peter; Kuijt, Wichert J.; Kikkert, Wouter J.; Grundeken, Maik J.; van Brussel, Peter M.; Stroobants, An K.; van Straalen, Jan P.; Fischer, Johan C.; Koch, Karel T.; Henriques, Jose P. S.; Piek, Jan J.; Tijssen, Jan G. P.; de Winter, Robbert J.

2014-01-01

337

Powdered activated carbon and membrane bioreactors (MBRPAC) for tannery wastewater treatment: long term effect on biological and filtration process performances  

Microsoft Academic Search

This paper describes the findings of an experimental investigation carried out on a pilot scale membrane bioreactor (MBR) with the addition of powdered activated carbon (PAC) to analyze improvements in effluent quality and in the filtration process. The results refer to a pilot plant monitoring stretched over a period of 594 days: 380 without PAC, 123 with a PAC concentration

G. Munz; R. Gori; G. Mori; C. Lubello

2007-01-01

338

Adapting and Implementing a Long-Term Nutrition and Physical Activity Curriculum to a Rural, Low-Income, Biethnic Community  

Microsoft Academic Search

This study adapted an urban-based school nutrition program for delivery in a rural community. Specific aims were to adapt the curriculum; expand it to include physical activity; determine effectiveness on students’ attitudes, knowledge, and self-efficacy; and assess teachers’ impressions. Three cohorts were established: 173 students taught by a resource teacher, 170 students taught by classroom teachers, and 187 students who

Elaine S. Belansky; Catherine Romaniello; Catherine Morin; Terry Uyeki; Rebecca L. Sawyer; Sharon Scarbro; Garry W. Auld; Lori Crane; Kim Reynolds; Richard F. Hamman; Julie A. Marshall

2006-01-01

339

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

Microsoft Academic Search

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

J J L van der Klink; R. W. B. Blonk; A. H. Schene; F J H van Dijk

2003-01-01

340

Long term hemodialysis aggravates lipolytic activity reduction and very low density, low density lipoproteins composition in chronic renal failure patients  

PubMed Central

Background Dyslipidemia, particularly hypertriglyceridemia is common in uremia, and represents an independent risk factor for atherosclerosis. Methods To investigate the effects of hemodialysis (HD) duration on very low density lipoprotein (VLDL) and low density lipoprotein (LDL) compositions and lipopolytic activities, 20 patients on 5 to 7 years hemodialysis were followed-up during 9 years. Blood samples were drawn at T0 (beginning of the study), T1 (3 years after initiating study), T2 (6 years after initiating study) and T3 (9 years after initiating study). T0 was taken as reference. Results Triacylglycerols (TG) values were correlated with HD duration (r = 0.70, P < 0.05). An increase of total cholesterol was noted at T2 and T3. Lowered activity was observed for lipoprotein lipase (LPL) (-44%) at T3 and hepatic lipase (HL) (-29%) at T1, (-64%) at T2 and (-73%) at T3. Inverse relationships were found between HD duration and LPL activity (r = -0.63, P < 0.05), and HL activity (r = -0.71, P < 0.01). At T1, T2 and T3, high VLDL-amounts and VLDL-TG and decreased VLDL-phospholipids values were noted. Increased LDL-cholesteryl esters values were noted at T1 and T2 and in LDL-unesterified cholesterol at T2 and T3. Conclusion Despite hemodialysis duration, VLDL-LDL metabolism alterations are aggravated submitting patients to a greater risk of atherosclerosis.

Mekki, Khedidja; Prost, Josiane; Remaoun, Mustapha; Belleville, Jacques; Bouchenak, Malika

2009-01-01

341

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.

Robinson, Gareth; Thorn, Robin; Reynolds, Darren

2013-01-01

342

Reduction in denitrification activity in field soils exposed to long term contamination by 2,4,6-trinitrotoluene (TNT)  

Microsoft Academic Search

Terrestrial sites contaminated with 2,4,6-trinitrotoluene (TNT) are a widespread and persistent problem and often contain non-vegetated areas with TNT concentrations well in excess of 1000 mg kg?1. In this study, we examined the effect of TNT on denitrification activity in field soils, and compared the sensitivity of denitrifying enzymes to TNT. DNA probes assessed the prevalence of nirS, nirK and

Steven D Siciliano; R Roy; C. W Greer

2000-01-01

343

An Important Role of Neural Activity-Dependent CaMKIV Signaling in the Consolidation of Long-Term Memory  

Microsoft Academic Search

Calcium\\/calmodulin-dependent protein kinase IV (CaMKIV) has been implicated in the regulation of CRE-dependent transcription. To investigate the role of this kinase in neuronal plasticity and memory, we generated transgenic mice in which the expression of a dominant-negative form of CaMKIV (dnCaMKIV) is restricted to the postnatal forebrain. In these transgenic mice, activity-induced CREB phosphorylation and c-Fos expression were significantly attenuated.

Hyejin Kang; Linus D. Sun; Coleen M. Atkins; Thomas R. Soderling; Matthew A. Wilson; Susumu Tonegawa

2001-01-01

344

Long-Term Exposure to Zidovudine Delays Cell Cycle Progression, Induces Apoptosis, and Decreases Telomerase Activity in Human Hepatocytes  

PubMed Central

Zidovudine (3?-azido-3?-deoxythymidine; AZT), which is currently used in the treatment of acquired immunodeficiency syndrome, has been shown to have anticancer properties. In the present study, we examined the mechanisms contributing to increased sensitivity of cancer cells to the growth-inhibitory effects of AZT. This was accomplished by incubating a hepatoma cell line (HepG2) and a normal liver cell line (THLE2) with AZT in continuous culture for up to 4 weeks and evaluating the number of viable and necrotic cells, the induction of apoptosis, cell cycle alterations, and telomerase activity. In HepG2 cells, AZT (2–100?M) caused significant dose-dependent decreases in the number of viable cells at exposures > 24 h. During a 1-week recover period, there was only a slight increase in the number of viable cells treated with AZT. The decrease in viable cells was associated with an induction of apoptosis, a decrease in telomerase activity, and S and G2/M phase arrest of the cell cycle. During the recovery period, the extent of apoptosis and telomerase activity returned to control levels, whereas the disruption of cell cycle progression persisted. Western blot analysis indicated that AZT caused a decrease in checkpoint kinase 1 (Chk1) and kinase 2 (Chk2) and an increase in phosphorylated Chk1 (Ser345) and Chk2 (Thr68). Similar effects, to lesser extent, were observed in THLE2 cells given much higher concentrations of AZT (50–2500?M). These data show that HepG2 cells are much more sensitive than THLE2 cells to AZT. They also indicate that a combination of a delay of cell cycle progression, an induction of apoptosis, and a decrease in telomerase activity is contributing to the decrease in the number of viable cells from AZT treatment, and that checkpoint enzymes Chk1 and Chk2 may play an important role in the delay of cell cycle progression.

Fang, Jia-Long; Beland, Frederick A.

2009-01-01

345

Long-term variations of the Campi Flegrei, Italy, volcanic system as revealed by the monitoring of hydrothermal activity  

Microsoft Academic Search

Long-duration time series of the chemical composition of fumaroles and of soil CO2 flux reveal that important variations in the activity of the Solfatara fumarolic field, the most important hydrothermal site of Campi Flegrei, occurred in the 2000–2008 period. A continuous increase of the CO2 concentrations and a general decrease of the CH4 concentrations are interpreted to be the consequence

G. Chiodini; S. Caliro; C. Cardellini; D. Granieri; R. Avino; A. Baldini; M. Donnini; C. Minopoli

2010-01-01

346

Agglomeration inhibition reflected stone-forming activity during long–term potassium citrate therapy in calcium stone formers  

Microsoft Academic Search

Objectives. The agglomeration of preformed crystals of calcium oxalate has been hypothesized to be the rate-limiting step in renal stone-forming activity (SFA). The effect of urine on the in vitro inhibition of agglomeration of seed crystals of calcium oxalate monohydrate, designated [tm], has been used to monitor SFA in calcium oxalate stone formers (CaOxSF). The objective of the present study

Harold A Fuselier; Kenneth Moore; Jill Lindberg; Fred E Husserl; Francis E Cole; Dirk J Kok; David Whitehead; Dante J Galliano; Donald T Erwin

1998-01-01

347

Nitrate inhibition of legume nodule growth and activity. I. Long term studies with a continuous supply of nitrate  

SciTech Connect

The synthesis and accumulation of nitrite has been suggested as a causative factor in the inhibition of legume nodules supplied with nitrate. Plants were grown in sand culture with a moderate level of nitrate (2.1 to 6.4 millimolar) supplied continuously from seed germination to 30 to 50 days after planting. In a comparison of nitrate treatments, a highly significant negative correlation between nitrite concentration in soybean (Glycine max (L.) Merr.) nodules and nodule fresh weight per shoot dry weight was found even when bacteroids lacked nitrate reductase (NR). However, in a comparison of two Rhizobium japonicum strains, there was only 12% as much nitrite in nodules formed by NR/sup -/ R. japonicum as in nodules formed by NR/sup +/ R. japonicum, and growth and acetylene reduction activity of both types of nodules was about equally inhibited. The very small concentration of nitrite found in P. vulgaris nodules was probably below that required for the inhibition of nitrogenase based on published in vitro experiments, and yet the specific acetylene reduction activity was inhibited 83% by nitrate. The overall results do not support the idea that nitrite plays a role in the inhibition of nodule growth and nitrogenase activity by nitrate.

Streeter, J.G.

1985-02-01

348

Leisure-time activity is an important determinant of long-term weight maintenance after weight loss in the Sibutramine Trial on Obesity Reduction and Maintenance (STORM trial)  

Microsoft Academic Search

Background: The success rate of long-term maintenance of weight loss in obese patients is usually low. To improve the success rate, determinants of long-term weight maintenance must be identified. Objective: The objective of the study was to identify determinants of long-term success in weight maintenance in obese subjects who completed the Sibutramine Trial on Obesity Reduction and Main- tenance (n

Marleen A van Baak; Edgar van Mil; V. Vastrup; Nick Finer; W. Saris

2003-01-01

349

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

350

Argon ion laser and halogen lamp activation of a dark and light resin composite: microhardness after long-term storage  

Microsoft Academic Search

The objective of this study was to evaluate in vitro light activation of the nano-filled resin composite Vita shade A1 and\\u000a A3 with a halogen lamp (QTH) and argon ion laser by Knoop microhardness profile. Materials and methods: Specimens of nanofilled\\u000a composite resin (Z350-3 M-ESPE) Vita shade A1 and A3 were prepared with a single increment inserted in 2.0-mm-thick and 3-mm

Alessandra Cassoni; Juliana de Oliveira Ferla; Luis Gustavo Barrotte Albino; Michel Nicolau Youssef; Jamil Awad Shibli; José Augusto Rodrigues

2010-01-01

351

Long-Term Activity-Dependent Plasticity of Action Potential Propagation Delay and Amplitude in Cortical Networks  

PubMed Central

Background The precise temporal control of neuronal action potentials is essential for regulating many brain functions. From the viewpoint of a neuron, the specific timings of afferent input from the action potentials of its synaptic partners determines whether or not and when that neuron will fire its own action potential. Tuning such input would provide a powerful mechanism to adjust neuron function and in turn, that of the brain. However, axonal plasticity of action potential timing is counter to conventional notions of stable propagation and to the dominant theories of activity-dependent plasticity focusing on synaptic efficacies. Methodology/Principal Findings Here we show the occurrence of activity-dependent plasticity of action potential propagation delays (up to 4 ms or 40% after minutes and 13 ms or 74% after hours) and amplitudes (up to 87%). We used a multi-electrode array to induce, detect, and track changes in propagation in multiple neurons while they adapted to different patterned stimuli in controlled neocortical networks in vitro. The changes did not occur when the same stimulation was repeated while blocking ionotropic gabaergic and glutamatergic receptors. Even though induction of changes in action potential timing and amplitude depended on synaptic transmission, the expression of these changes persisted in the presence of the synaptic receptor blockers. Conclusions/Significance We conclude that, along with changes in synaptic efficacy, propagation plasticity provides a cellular mechanism to tune neuronal network function in vitro and potentially learning and memory in the brain.

Bakkum, Douglas J.; Chao, Zenas C.; Potter, Steve M.

2008-01-01

352

Long-Term Consumption of Platycodi Radix Ameliorates Obesity and Insulin Resistance via the Activation of AMPK Pathways.  

PubMed

This study was designed to evaluate the effects and mechanism of Platycodi radix, having white balloon flower (Platycodon grandiflorum for. albiflorum (Honda) H. Hara) on obesity and insulin resistance. The extracts of Platycodi radix with white balloon flower were tested in cultured cells and administered into mice on a high-fat diet. The Platycodi radix activated the AMPK/ACC phosphorylation in C2C12 myotubes and also suppressed adipocyte differentiation in 3T3-L1 cells. In experimental animal, it suppressed the weight gain of obese mice and ameliorated obesity-induced insulin resistance. It also reduced the elevated circulating mediators, including triglyceride (TG), T-CHO, leptin, resistin, and monocyte chemotactic protein (MCP)-1 in obesity. As shown in C2C12 myotubes, the administration of Platycodi radix extracts also recovered the AMPK/ACC phosphorylation in the muscle of obese mice. These results suggest that Platycodi radix with white balloon flower ameliorates obesity and insulin resistance in obese mice via the activation of AMPK/ACC pathways and reductions of adipocyte differentiation. PMID:22829857

Lee, Chae Eun; Hur, Haeng Jeon; Hwang, Jin-Taek; Sung, Mi Jeong; Yang, Hye Jeong; Kim, Hyun-Jin; Park, Jae Ho; Kwon, Dae Young; Kim, Myung-Sunny

2012-01-01

353

Long-Term Consumption of Platycodi Radix Ameliorates Obesity and Insulin Resistance via the Activation of AMPK Pathways  

PubMed Central

This study was designed to evaluate the effects and mechanism of Platycodi radix, having white balloon flower (Platycodon grandiflorum for. albiflorum (Honda) H. Hara) on obesity and insulin resistance. The extracts of Platycodi radix with white balloon flower were tested in cultured cells and administered into mice on a high-fat diet. The Platycodi radix activated the AMPK/ACC phosphorylation in C2C12 myotubes and also suppressed adipocyte differentiation in 3T3-L1 cells. In experimental animal, it suppressed the weight gain of obese mice and ameliorated obesity-induced insulin resistance. It also reduced the elevated circulating mediators, including triglyceride (TG), T-CHO, leptin, resistin, and monocyte chemotactic protein (MCP)-1 in obesity. As shown in C2C12 myotubes, the administration of Platycodi radix extracts also recovered the AMPK/ACC phosphorylation in the muscle of obese mice. These results suggest that Platycodi radix with white balloon flower ameliorates obesity and insulin resistance in obese mice via the activation of AMPK/ACC pathways and reductions of adipocyte differentiation.

Lee, Chae Eun; Hur, Haeng Jeon; Hwang, Jin-Taek; Sung, Mi Jeong; Yang, Hye Jeong; Kim, Hyun-Jin; Park, Jae Ho; Kwon, Dae Young; Kim, Myung-Sunny

2012-01-01

354

Long-term changes in trigeminal ganglionic and thalamic neuronal activities following inferior alveolar nerve transection in behaving rats.  

PubMed

The transection of the inferior alveolar nerve (IANx) produces allodynia in the whisker pad (V2 division) of rats. Ectopic discharges from injured trigeminal ganglion (TG) neurons and thalamocortical reorganization are possible contributors to the sensitization of uninjured V2 primary and CNS neurons. To test which factor is more important, TG and ventroposterior medial nucleus (VPM) neurons were longitudinally followed before, during, and after IANx for up to 80 d. Spontaneous discharges and mechanical stimulation-evoked responses were recorded in conscious and in anesthetized states. Results show (1) a sequential increase in spontaneous activities, first in the injured TG neurons of the IAN (2-30 d), followed by uninjured V2 ganglion neurons (6-30 d), and then VPM V2 neurons (7-30 d) after IANx; (2) ectopic discharges included burst and regular firing patterns in the IAN and V2 branches of the TG neurons; and (3) the receptive field expanded, the modality shifted, and long-lasting after-discharges occurred only in VPM V2 neurons. All of these changes appeared in the late or maintenance phase (7-30 d) and disappeared during the recovery phase (40-60 d). These observations suggest that ectopic barrages in the injured IAN contribute more to the development of sensitization, whereas the modality shift and evoked after-discharges in the VPM thalamic neurons contribute more to the maintenance phase of allodynia by redirecting tactile information to the cortex as nociceptive. PMID:23136441

Tseng, Wan-Ting; Tsai, Meng-Li; Iwata, Koichi; Yen, Chen-Tung

2012-11-01

355

Verapamil does not modify catalytic activity of CYP450 in rainbow trout after long-term exposure.  

PubMed

Little is known about the effects of the cardiovascular drug verapamil (VRP) on metabolic processes in fish. Most calcium channel blockers including VRP are metabolized by cytochrome P450 (CYP450) enzymes. In this study we investigated the in vivo effect of VRP on some CYP450-mediated reactions in juvenile rainbow trout (Oncorhynchus mykiss). Fish were exposed to sublethal concentrations of VRP (0.5, 27 and 270 ?g l(-1)) for 0, 21, and 42 day. The following CYP450-mediated reactions were studied in hepatic microsomes: O-dealkylation of ethoxyresorufin, methoxyresorufin, and pentoxyresorufin, hydroxylation of coumarin, tolbutamide, and p-nitrophenol, and O-debenzylation of 7-benzyloxy-4-trifluoromethylcoumarin. The amounts of products of these reactions did not differ among fish exposed to different levels of VRP and control fish. This suggests that the levels of VPR used did not alter catalytic activity of the selected CYP450 enzymes. In conclusion, none of the investigated CYP450-mediated reactions has potential as a biomarker to monitor VRP contamination of the aquatic environment. PMID:22244749

Burkina, V; Zamaratskaia, G; Randak, T; Li, Z H; Fedorova, G; Pickova, J; Zlabek, V

2012-05-01

356

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

357

The role of antigenic stimulation and cytotoxic T cell activity in regulating the long-term immunopathogenesis of HIV: mechanisms and clinical implications.  

PubMed Central

This paper develops a predictive mathematical model of cell infection, host immune response and viral replication that reproduces observed long-term trends in human immunodeficiency virus (HIV) pathogenesis. Cell activation induced by repeated exposure to many different antigens is proposed as the principal mechanism of providing target cells for HIV infection and, hence, of CD4+ T cell depletion, with regulation of the overall T cell pool size causing concomitant CD8 pool increases. The model correctly predicts the cross-patient variability in disease progression, the rate of which is found to depend on the efficacy of anti-HIV cytotoxic T lymphocyte responses, overall viral pathogenicity and random effects. The model also predicts a variety of responses to anti-viral therapy, including episodic residual viral replication and discordant responses and we find that such effects can be suppressed by increasing the potency of treatment.

Fraser, C.; Ferguson, N. M.; de Wolf, F.; Anderson, R. M.

2001-01-01

358

Long-term fish oil supplementation attenuates seizure activity in the amygdala induced by 3-mercaptopropionic acid in adult male rats.  

PubMed

Several studies have provided evidence of significant effects of omega-3 fatty acids on brain functionality, including seizures and disorders such as epilepsy. Fish oil (FO) is a marine product rich in unsaturated omega-3 fatty acids. Considering that the amygdala is one of the brain structures most sensitive to seizure generation, we aimed to evaluate the effect of long-term chronic FO supplementation (from embryonic conception to adulthood) on the severity of seizures and amygdaloid electroencephalographic activity (EEG) in a 3-mercaptopropionic acid (3-MPA)-induced seizure model using adult rats. Female Wistar rats were fed a commercial diet supplemented daily with FO (300mg/kg) from puberty through mating, gestation, delivery, and weaning of the pups. Only the male pups were then fed daily with a commercial diet supplemented with the same treatment as the dam up to the age of 150days postpartum, when they were bilaterally implanted in the amygdala to record behavior and EEG activity before, during, and after seizures induced by administering 3-MPA. Results were compared with those obtained from rats supplemented with palm oil (PO) and rats treated with a vehicle (CTRL). The male rats treated with FO showed longer latency to seizure onset, fewer convulsive episodes, and attenuated severity compared those in the PO and CTRL groups according to the Racine scale. Moreover, long-term FO supplementation was associated with a reduction of the absolute power (AP) of the fast frequencies (12-25Hz) in the amygdala during the seizure periods. These findings support the idea that chronic supplementation with omega-3 of marine origin may have antiseizure properties as other studies have suggested. PMID:24657504

Flores-Mancilla, L E; Hernández-González, M; Guevara, M A; Benavides-Haro, D E; Martínez-Arteaga, P

2014-04-01

359

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.

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

2014-01-01

360

Linking short- and long-term deformation along an active margin: regional tectono-geomorphic patterns in light of the 2010 Maule Chile earthquake (M8.8)  

NASA Astrophysics Data System (ADS)

Strongly coupled subduction zones are known to have generated some of the largest earthquakes on Earth (megathrust earthquakes). These regions are also associated with an array of tectonic landforms, including multiple marine and fluvial terraces, which are intimately coupled with the long-term effects of seismogenic processes. Thus understanding the parameters that control the along-strike propagation of megathrust earthquake ruptures combined with the analysis of tectonic landforms is fundamental for the assessment of seismic hazards and risk mitigation. Here we report on the 2010 Maule earthquake that ruptured ~500 km of the central Chile margin. Modeling of GPS data during the interseismic and co-seismic periods have revealed segmentation in two main areas of high slip release and coupling. However, the spatiotemporal persistence of these segments and their relation with mechanical properties of the forearc is still poorly understood. To elucidate the relationships between short-term rupture segments and long-term tectono-geomorphic entities of the forearc we quantified permanent, long-term deformation using marine terraces in the Maule rupture zone and evaluate its relation with inter- and co-seismic patterns. We used the MIS-5 marine terrace, an ubiquitous geomorphic reference surface along the coast of central Chile, which we correlated with LiDAR images, field observations and new OSL ages. Furthermore, we evaluated the mechanisms of uplift by forward modeling of plate boundary slip. Coeval terraces are sharply offset across discrete crustal faults and also deformed in areas of broad crustal warping with wavelengths of ~100 km, reflecting activity of deep-seated structures within the interplate zone, both at the southern and northern sectors of the Maule rupture, where uplift rates reach 1.8 mm/yr. The central part, in turn, is characterized by a lesser degree of permanent uplift. Based on the similarities between seismic-cycle deformation and historical earthquake ruptures we propose that the southern sector of the Maule rupture zone constitutes a stable, discrete seismotectonic boundary. In contrast, the northern sector constitutes a rather diffuse boundary that may prevent rupture propagation of some earthquakes. Our modeling results suggest that in the north slip at the plate interface must be deeper than that inferred for the 2010 event to uplift the coast.

Jara-Muñoz, Julius; Melnick, Daniel; Brill, Dominik; Strecker, Manfred

2014-05-01

361

Basics (Long-Term Care)  

MedlinePLUS

... Term Care? Expand Long-term Care Considerations for LGBT Adults Expand Health Disparities Impacting LTC Expand Caregivers ... on Alzheimer's Disease Lesbian, Gay, Bisexual and Transgender (LGBT) community Home About Us Accessibility Disclaimer Privacy Contact ...

362

BHT, Long-Term Toxicity.  

National Technical Information Service (NTIS)

The Chemical Manufacturers Association (CMA) recently received preliminary results of a long-term toxicity study on butylated hydroxytoluene (BHT) in rats. The study was conducted by the Institute of Toxicology, National Food Institute of Denmark. Prelimi...

1983-01-01

363

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.

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

2011-01-01

364

Active immunization to tumor necrosis factor-? is effective in treating chronic established inflammatory disease: a long-term study in a transgenic model of arthritis  

PubMed Central

Introduction Passive blockade of tumor necrosis factor-alpha (TNF-?) has demonstrated high therapeutic efficiency in chronic inflammatory diseases, such as rheumatoid arthritis, although some concerns remain such as occurrence of resistance and high cost. These limitations prompted investigations of an alternative strategy to target TNF-?. This study sought to demonstrate a long-lasting therapeutic effect on established arthritis of an active immunotherapy to human (h) TNF-? and to evaluate the long-term consequences of an endogenous anti-TNF-? response. Methods hTNF-? transgenic mice, which spontaneously develop arthritides from 8 weeks of age, were immunized with a heterocomplex (TNF kinoid, or TNF-K) composed of hTNF-? and keyhole limpet hemocyanin after disease onset. We evaluated arthritides by clinical and histological assessment, and titers of neutralizing anti-hTNF-? antibody by enzyme-linked immunosorbent assay and L929 assay. Results Arthritides were dramatically improved compared to control mice at week 27. TNF-K-treated mice exhibited high levels of neutralizing anti-hTNF-? antibodies. Between weeks 27 and 45, all immunized mice exhibited symptoms of clinical deterioration and a parallel decrease in anti-hTNF-? neutralizing antibodies. A maintenance dose of TNF-K reversed the clinical deterioration and increased the anti-hTNF-? antibody titer. At 45 weeks, TNF-K long-term efficacy was confirmed by low clinical and mild histological scores for the TNF-K-treated mice. Injections of unmodified hTNF-? did not induce a recall response to hTNF-? in TNF-K immunized mice. Conclusions Anti-TNF-? immunotherapy with TNF-K has a sustained but reversible therapeutic efficacy in an established disease model, supporting the potential suitability of this approach in treating human disease.

2009-01-01

365

Solar Activity and Global Warming Revisited  

NASA Astrophysics Data System (ADS)

While in general the changes in surface air temperature follow the changes in solar activity proving the solar influences on climate, in the last few decades solar activity has remained more or less constant while temperature has continued increasing which is a strong argument in favor of anthropogenic influences on climate. In the same period the correlation between solar and geomagnetic activity has decreased, both in the 11-year cycle and on secular time scale. The solar activity index commonly used for long-term studies is the sunspot number as it has the longest data record. But sunspots reflect only the solar activity originating from closed magnetic field regions. The regions of open magnetic field - coronal holes, sources of high speed solar wind and drivers of recurrent geomagnetic activity, are not accounted for in the sunspot index. It appears that in the last decades the impact of coronal holes has increased which can be explained by the increasing tilt of the heliospheric current sheet. This increased tilt means that the Earth encounters two high speed streams from coronal holes per solar rotation and higher geomagnetic activity. On the other hand, the tilt of the heliospheric current sheet is related to the galactic cosmic rays modulation, and galactic cosmic rays are considered key agents mediating solar activity influences on terrestrial temperature. Therefore, using the sunspot number alone as a measure of solar activity leads to the underestimation of the role of solar activity for the global warming in the recent decades.

Georgieva, K.; Kirov, B.

2006-03-01

366

Long term anti-tumour necrosis factor ? monotherapy in rheumatoid arthritis: effect on radiological course and prognostic value of markers of cartilage turnover and endothelial activation  

PubMed Central

Objectives: To investigate the effect of prolonged neutralisation of tumour necrosis factor ? (TNF?) on the radiological course in rheumatoid arthritis (RA). To assess whether the radiological course can be predicted by clinical variables or biological markers of cartilage and synovium turnover and of endothelial activation. Patients and methods: Forty seven patients with active RA enrolled at our centre in monotherapy trials with adalimumab (D2E7), a fully human anti-TNF? monoclonal antibody, were studied for two years. Radiographs of hands and feet obtained at baseline and after one and two years were scored in chronological order by a single, blinded observer using the modified Sharp method. Radiological course was classified as stable or progressive using the smallest detectable difference as cut off point. The relation between radiological course and serum markers of cartilage and synovium turnover (metalloproteinases (MMP-1 and MMP-3), cartilage oligomeric matrix protein (COMP), human cartilage glycoprotein-39 (HC gp-39)), endothelial activation (soluble E-selectin and intercellular adhesion molecule (ICAM-1)), and integrated measures of disease activity were assessed using univariate and multivariate analysis. Results: Radiological evaluation was performed in 36 patients with paired sets of radiographs at baseline and two years. After two years a total of 15/36 (42%) presented no radiological progression. More patients with stable radiological course were still receiving anti-TNF? treatment after two years (13/15 (87%) v 11/21 (52%); p=0.03) and had lower baseline COMP and sICAM-1 levels (p=0.01 and 0.04, respectively) than those in the group with progressive disease. In a logistic regression model the combination of sustained TNF neutralisation and baseline COMP and sICAM-1 levels was predictive for radiological outcome (p=0.03). C reactive protein and disease activity score area under the curve were significantly correlated with changes in radiological scores after two years (r=0.40 and 0.37, p<0.05). Long term TNF? neutralisation decreased the levels of COMP, sICAM, MMPs, and HC gp-39, but not sE-selectin. Conclusion: The results suggest that long term monotherapy with anti-TNF? has a positive effect on radiological outcome and modulates cartilage and synovium turnover as measured by biological markers. Baseline serum sICAM-1 levels and COMP levels may be helpful to identify patients with progressive or non-progressive radiological outcome.

den Broeder, A A; Joosten, L; Saxne, T; Heinegard, D; Fenner, H; Miltenburg, A; Frasa, W; van Tits, L J; Buurman, W; van Riel, P L C M; van de Putte, L B A; Barrera, P

2002-01-01

367

Solar Activity Indices  

NASA Astrophysics Data System (ADS)

Solar activity is driven by the temporally and spatially varying distribution of magnetic flux in the photosphere, chromosphere and corona. It covers a range of phenomena at all levels in the solar atmosphere and time-scales ranging from seconds and minutes (SOLAR FLARES and SOLAR CORONAL MASS EJECTIONS), through months (the evolution of ACTIVE REGIONS and SOLAR ACTIVITY COMPLEXES), to the 11 (or...

Tapping, K.; Murdin, P.

2000-11-01

368

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

369

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

370

Social activity decreases risk of placement in a long-term care facility for a prospective sample of community-dwelling older adults.  

PubMed

The purpose of this study was to determine the role of modifiable factors in the risk of long-term care (LTC) placement. Using data from a cohort of community-residing older adults (N = 189), a secondary analysis was conducted of the contribution of social activity, sleep disturbances, and depressive symptoms to the risk of LTC placement. Analyses controlled for cognitive and functional impairment, age, and medical conditions. Within 5 years, 20% of participants were placed in a LTC facility. Each unit increase in social activity was associated with a 24% decrease in the risk of placement (odds ratio [OR] = 0.763, p = 0.001, 95% confidence interval [CI] [0.65, 0.89]). Cognitive impairment (OR = 3.05, p = 0.017, 95% CI [1.23, 7.59]), medical conditions (OR = 1.22, p = 0.039, 95% CI [1.01, 1.47]), and age (OR = 1.101, p = 0.030, 95% CI [1.01, 1.20]) were also significant individual predictors of placement. Although many of the strongest risk factors for placement are not modifiable, older adults who engage in more social activity outside the home may be able to delay transition from independent living. PMID:24444452

Miller, Lyndsey M; Dieckmann, Nathan F; Mattek, Nora C; Lyons, Karen S; Kaye, Jeffrey A

2014-01-01

371

Long term results of early active extension and passive flexion mobilization following one-stage tendon grafting for neglected injuries of the flexor digitorum profundus in children.  

PubMed

We retrospectively reviewed the long-term clinical outcomes of one-stage flexor tendon grafting for seven paediatric patients with isolated flexor digitorum profundus (FDP) tendon injuries in Zones 1 or 2. Free tendon grafts (one palmaris longus tendons and six plantaris tendons) were used for reconstruction by Pulvertaft's procedure. The ages of the patients at reconstruction ranged from 7 to 15 (mean 11) years. The time from injury to surgery ranged from three to 78 (mean 25) months. These patients were followed up from 2.5 to 21 years after surgery (mean 8.5 years). All cases were started on early active extension and passive flexion according to the modified Kleinert mobilization for postoperative rehabilitation. The mean active motion after surgery was 49° (range 20-80°) for the DIP joints and 106° (range 95-110°) for the PIP joints. The total active range of motion was on average 237° (range 195-275°). Excellent results were achieved in five patients, good in one, and fair in one. Growth arrest of the distal phalanx was seen in one patient. One-stage flexor tendon grafting in paediatric patients combined with early controlled mobilization can be used to reconstruct neglected isolated ruptures of the FDP tendon with satisfactory results. PMID:21282212

Yamazaki, Hiroshi; Kato, Hiroyuki; Uchiyama, Shigeharu; Iwasaki, Norimasa; Ishikura, Hisamitsu; Minami, Akio

2011-05-01

372

Long-term information and distributed neural activation are relevant for the "internal features advantage" in face processing: electrophysiological and source reconstruction evidence.  

PubMed

In face processing tasks, prior presentation of internal facial features, when compared with external ones, facilitates the recognition of subsequently displayed familiar faces. In a previous ERP study (Olivares & Iglesias, 2010) we found a visibly larger N400-like effect when identity mismatch familiar faces were preceded by internal features, as compared to prior presentation of external ones. In the present study we contrasted the processing of familiar and unfamiliar faces in the face-feature matching task to assess whether the so-called "internal features advantage" relies mainly on the use of stored face-identity-related information or if it might operate independently from stimulus familiarity. Our participants (N = 24) achieved better performance with internal features as primes and, significantly, with familiar faces. Importantly, ERPs elicited by identity mismatch complete faces displayed a negativity around 300-600 msec which was clearly enhanced for familiar faces primed by internal features when compared with the other experimental conditions. Source reconstruction showed incremented activity elicited by familiar stimuli in both posterior (ventral occipitotemporal) and more anterior (parahippocampal (ParaHIP) and orbitofrontal) brain regions. The activity elicited by unfamiliar stimuli was, in general, located in more posterior regions. Our findings suggest that the activation of multiple neural codes is required for optimal individuation in face-feature matching and that a cortical network related to long-term information for face-identity processing seems to support the internal feature effect. PMID:24025156

Olivares, Ela I; Saavedra, Cristina; Trujillo-Barreto, Nelson J; Iglesias, Jaime

2013-01-01

373

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

374

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.

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

2014-01-01

375

CaM kinase II and protein kinase C activations mediate enhancement of long-term potentiation by nefiracetam in the rat hippocampal CA1 region.  

PubMed

Nefiracetam is a pyrrolidine-related nootropic drug exhibiting various pharmacological actions such as cognitive-enhancing effect. We previously showed that nefiracetam potentiates NMDA-induced currents in cultured rat cortical neurons. To address questions whether nefiracetam affects NMDA receptor-dependent synaptic plasticity in the hippocampus, we assessed effects of nefiracetam on NMDA receptor-dependent long-term potentiation (LTP) by electrophysiology and LTP-induced phosphorylation of synaptic proteins by immunoblotting analysis. Nefiracetam treatment at 1-1000 nM increased the slope of fEPSPs in a dose-dependent manner. The enhancement was associated with increased phosphorylation of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptor through activation of calcium/calmodulin-dependent protein kinase II (CaMKII) without affecting synapsin I phosphorylation. In addition, nefiracetam treatment increased PKCalpha activity in a bell-shaped dose-response curve which peaked at 10 nM, thereby increasing phosphorylation of myristoylated alanine-rich protein kinase C substrate and NMDA receptor. Nefiracetam treatment did not affect protein kinase A activity. Consistent with the bell-shaped PKCalpha activation, nefiracetam treatment enhanced LTP in the rat hippocampal CA1 region with the same bell-shaped dose-response curve. Furthermore, nefiracetam-induced LTP enhancement was closely associated with CaMKII and PKCalpha activation with concomitant increases in phosphorylation of their endogenous substrates except for synapsin I. These results suggest that nefiracetam potentiates AMPA receptor-mediated fEPSPs through CaMKII activation and enhances NMDA receptor-dependent LTP through potentiation of the post-synaptic CaMKII and protein kinase C activities. Together with potentiation of nicotinic acetylcholine receptor function, nefiracetam-enhanced AMPA and NMDA receptor functions likely contribute to improvement of cognitive function. PMID:18445137

Moriguchi, Shigeki; Shioda, Norifumi; Han, Feng; Narahashi, Toshio; Fukunaga, Kohji

2008-08-01

376

Amyloid beta prevents activation of calcium/calmodulin-dependent protein kinase II and AMPA receptor phosphorylation during hippocampal long-term potentiation.  

PubMed

Accumulation of amyloid beta-peptides (Abeta) in the brain has been linked with memory loss in Alzheimer's disease and its animal models. However, the synaptic mechanism by which Abeta causes memory deficits remains unclear. We previously showed that acute application of Abeta inhibited long-term potentiation (LTP) in the hippocampal perforant path via activation of calcineurin, a Ca2+ -dependent protein phosphatase. This study examined whether Abeta could also inhibit Ca2+/calmodulin dependent protein kinase II (CaMKII), further disrupting the dynamic balance between protein kinase and phosphatase during synaptic plasticity. Immunoblot analysis was conducted to measure autophosphorylation of CaMKII at Thr286 and phosphorylation of the GluR1 subunit of AMPA receptors in single rat hippocampal slices. A high-frequency tetanus applied to the perforant path significantly increased CaMKII autophosphorylation and subsequent phosphorylation of GluR1 at Ser831, a CaMKII-dependent site, in the dentate area. Acute application of Abeta1-42 inhibited dentate LTP and associated phosphorylation processes, but was without effect on phosphorylation of GluR1 at Ser845, a protein kinase A-dependent site. These results suggest that activity-dependent CaMKII autophosphorylation and AMPA receptor phosphorylation are essential for dentate LTP. Disruption of such mechanisms could directly contribute to Abeta-induced deficits in hippocampal synaptic plasticity and memory. PMID:15212428

Zhao, Danyun; Watson, Joseph B; Xie, Cui-Wei

2004-11-01

377

Long-term operation of a novel pilot-scale six tanks alternately operating activated sludge process in treating domestic wastewater.  

PubMed

The performance of a new pilot-scale six tanks activated sludge process has been evaluated for 303 d, receiving real domestic wastewater with a flow rate of 15-24.4 L/h. Partial nitrification via nitrite and microbial community structure were investigated in this system. The result shows that the nitrite accumulation rate was achieved successfully over 94% in the last aerobic compartment through a combination of short hydraulic retention time and low dissolved oxygen (DO) level. Fluorescence in situ hybridization analysis was used to correlate ammonia-oxidizing bacteria (AOB) numbers with nutrient removal via nitrite. It was shown that in response to complete and partial nitrification modes, the numbers of AOB population were 7.7 x 10(7) cells/g mixed liquor suspended solids (MLSS) and 5.31 x 10(8) cells/g MLSS, respectively. The morphology of the sludge indicated that there is a small rod-shaped and spherical cluster which was mainly dominantly bacterial according to scanning electron microscope. Higher pollutant removal efficiencies of 86.2%, 98%, and 96.1%, for total nitrogen, NH4+ - N, and total phosphorus, respectively, were achieved by a long-term operation of the six tanks activated sludge process at a low DO concentration and low chemical oxygen demand to nitrogen ratio which were approximately equal to the complete nitrification-ldenitrification with the addition of an external carbon source at a concentration of 1.5-2.5 mg/L. PMID:24956781

Mohammed, R N; Abu-Alhail, S; Xi-Wu, L

2014-08-01

378

Long-term tissue distribution and steady state activity ratios of 232Th and its daughters in rats after intravascular injection of Thorotrast.  

PubMed

To estimate the absorbed dose in the critical organs of Thorotrast patients, it is necessary to know not only the distribution and concentration of 232Th but also its daughter nuclides in the body. The present investigation was undertaken in order to clarify the long-term 232Th tissue distribution and steady state activity ratios between subsequent daughters in the critical tissues using about 30 Wister male rats, as a basis for estimating absorbed doses. The tissue distribution of thorium was examined by means of an autoradiography of the whole body and/or the gamma-ray spectrometry at various times during 2 to 24 months following injection. The concentrations of daughter nuclides in tissues were determined by repetitive gamma examination over a period from 1 hr to 35 days after being sacrificed. The data indicate (1) that approximately 90% of injected Thorotrast is retained in the body for a prolonged period, but about 50% of radium and 10% of radon produced from thorium are eliminated from the body, (2) that the mean steady state activity ratios of 224Ra and 212Pb to 228Th for liver are 0.56 and 0.28, and 0.54 and 0.16 for spleen, 0.58 and 0.82 for lungs, respectively, and (3) that the parent 228Th is translocated to the bone. PMID:2554457

Norimura, T; Tsuchiya, T; Hatakeyama, S; Yamamoto, H; Okajima, S

1989-09-01

379

Autologous tumor cell vaccines for post-operative active-specific immunotherapy of colorectal carcinoma: long-term patient survival and mechanism of function.  

PubMed

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide. Surgery remains the primary curative treatment but nearly 50% of patients relapse as consequence of micrometastatic or minimal residual disease (MRD) at the time of surgery. Spontaneous T-cell-mediated immune responses to CRC tumor-associated antigens (TAAs) in tumor-draining lymph nodes and in the bone marrow (BM) lead to infiltration of the tumors by lymphocytes. Certain types of such tumor-infiltrating lymphocytes (TILs) have a positive and others a negative impact on the patients' prognosis. This review focuses on advances in CRC active-specific immunotherapy (ASI), in particular on results from randomized controlled clinical studies employing therapeutic autologous tumor cell vaccines. The observed improvement of long-term survival is explained by activation and mobilization of a pre-existing repertoire of tumor-reactive memory T cells which, according to recent discoveries, reside in distinct niches of patients' bone marrow in neighborhood with hematopoietic (HSC) and mesenchymal (MSC) stem cells. Interestingly, memory T cells also contain a subset of stem memory T cells (SMTs) in addition to effector (EMTs) and central memory T cells (CMTs). The mechanism of function of a therapeutic vaccine in a chronic disease is distinct from that of prophylactic vaccines which have to generate de novo protective immune responses. The advantage of autologous vaccines for mobilization of a broad and highly individual repertoire of memory T cells will be discussed. PMID:24219122

Schirrmacher, Volker; Fournier, Philippe; Schlag, Peter

2014-01-01

380

Activity-dependent long-term enhancement of transmitter release by presynaptic 3',5'-cyclic GMP in cultured hippocampal neurons.  

PubMed

Long-term potentiation (LTP) in hippocampus is a type of synaptic plasticity that is thought to be involved in learning and memory. Several lines of evidence suggest that LTP involves 3',5'-cyclic GMP (cGMP), perhaps as an activity-dependent presynaptic effector of one or more retrograde messengers (refs 2-12, but see ref. 13). However, previous results are also consistent with postsynaptic effects of cGMP. This is difficult to test in hippocampal slices, but more rigorous tests are possible in dissociated cell culture. We have therefore developed a reliable method for producing N-methyl-D-aspartate (NMDA) receptor-dependent LTP at synapses between individual hippocampal pyramidal neurons in culture. We report that inhibitors of guanylyl cyclase or of cGMP-dependent protein kinase block potentiation by either tetanic stimulation or low-frequency stimulation paired with postsynaptic depolarization. Conversely, application of 8-Br-cGMP to the bath or injection of cGMP into the presynaptic neuron produces activity-dependent long-lasting potentiation. The potentiation by cGMP involves an increase in transmitter release that is in part independent of changes in the presynaptic action potential. These results support a presynaptic role for cGMP in LTP. PMID:7596438

Arancio, O; Kandel, E R; Hawkins, R D

1995-07-01