scholarly journals Linking long- and short-term emission variability in pulsars

2019 ◽  
Vol 488 (4) ◽  
pp. 5702-5712 ◽  
Author(s):  
P R Brook ◽  
A Karastergiou ◽  
S Johnston

ABSTRACT It is now known that the emission from radio pulsars can vary over a wide range of time-scales, from fractions of seconds to decades. However, it is not yet known if long- and short-term emission variability are caused by the same physical processes. It has been observed that long-term emission variability is often correlated with rotational changes in the pulsar. We do not yet know if the same is true of short-term emission variability, as the rotational changes involved cannot be directly measured over such short time-scales. To remedy this, we propose a continuous pulsar monitoring technique that permits the statistical detection of any rotational changes in nulling and mode-changing pulsars with certain properties. Using a simulation, we explore the range of pulsar properties over which such an experiment would be possible.

2011 ◽  
Vol 8 (4) ◽  
pp. 1023-1030 ◽  
Author(s):  
P. Y. Oikawa ◽  
L. Li ◽  
M. P. Timko ◽  
J. E. Mak ◽  
M. T. Lerdau

Abstract. Plants are an important source of atmospheric methanol (MeOH), the second most abundant organic gas after methane. Factors regulating phytogenic MeOH production are not well constrained in current MeOH emission models. Previous studies have indicated that light may have a direct influence on MeOH production. As light is known to regulate cell wall expansion, it was predicted that light would stimulate MeOH production through the pectin methylesterase (PME) pathway. MeOH emissions normalized for stomatal conductance (gs) did not, however, increase with light over short time scales (20–30 min). After experimentally controlling for gs and temperature, no light activation of PME activity or MeOH emission was observed. The results clearly demonstrate that light does not directly influence short-term changes in MeOH production and emission. Our data suggest that substrate limitation may be important in regulating MeOH production over short time scales. Future investigation of the long-term impacts of light on MeOH production may increase understanding of MeOH emission dynamics at the seasonal time scale.


2011 ◽  
Vol 8 (1) ◽  
pp. 415-434
Author(s):  
P. Y. Oikawa ◽  
L. Li ◽  
M. P. Timko ◽  
J. E. Mak ◽  
M. T. Lerdau

Abstract. Plants are an important source of atmospheric methanol (MeOH), the second most abundant organic gas after methane. Factors regulating phytogenic MeOH production are not well constrained in current MeOH emission models. Previous studies have indicated that light may have a direct influence on MeOH production. As light is known to regulate cell wall expansion, it was predicted that light would stimulate MeOH production through the pectin methylesterase (PME) pathway. MeOH emissions normalized for stomatal conductance (gs) did not, however, increase with light over short time scales (20–30 min). After experimentally controlling for gs and temperature, no light activation of PME activity or MeOH emission was observed. The results clearly demonstrate that light does not directly influence short-term changes in MeOH production and emission. Our data suggest that substrate limitation may be important in regulating MeOH production over short time scales. Future investigation of the long-term impacts of light on MeOH production may increase understanding of MeOH emission dynamics at the seasonal time scale.


1996 ◽  
Vol 173 ◽  
pp. 291-292
Author(s):  
M.R.S. Hawkins

Quasars are known to vary in brightness over a wide range of time scales. Short term intrinsic variability has been well documented, and a strong case can be made that long term variation is due to microlensing. In this paper the effect of time dilation as a means for distinguishing between intrinsic variation and gravitational lensing is discussed.


1984 ◽  
Vol 16 (3-4) ◽  
pp. 623-633
Author(s):  
M Loxham ◽  
F Weststrate

It is generally agreed that both the landfill option, or the civil techniques option for the final disposal of contaminated harbour sludge involves the isolation of the sludge from the environment. For short time scales, engineered barriers such as a bentonite screen, plastic sheets, pumping strategies etc. can be used. However for long time scales the effectiveness of such measures cannot be counted upon. It is thus necessary to be able to predict the long term environmenttal spread of contaminants from a mature landfill. A model is presented that considers diffusion and adsorption in the landfill site and convection and adsorption in the underlaying aquifer. From a parameter analysis starting form practical values it is shown that the adsorption behaviour and the molecular diffusion coefficient of the sludge, are the key parameters involved in the near field. The dilution effects of the far field migration patterns are also illustrated.


2012 ◽  
Vol 8 (S291) ◽  
pp. 208-208
Author(s):  
Augustine Chukwude

AbstractWe investigate the spin-down behaviour of a sample of 25 radio pulsars on decadal timescales (~ 18 years) using a continuous timing data obtained over a period of at Hartebeesthoek Radio Astronomy Observatory (HartRAO). Particular attention is placed on achieving a better time resolution of both the short-term and long-term changes in pulsar spin-down using local phase-coherent measurements of the spin-down rates (). We demonstrate that the spin-down of radio pulsars is generally complicated by a superposition of processes that may or may not be related. Specifically, our results show that (i) for 7 pulsars, the observed spin-down variation is largely stochastic, characterized by random and sustained jumps in of varying amplitudes, (ii) for 9 objects, the spin-down evolution shows dominant monotonic variations in superimposed on short-term stochastic jumps in the parameter, and (iii) for the remaining 9 pulsars, the long-term spin-down evolution is non-monotonic, dominated by some systematic excursion in the measured spin-down rates.


Author(s):  
Vidhi Shah

Abstract: This research was conducted to gather data and understand the perception what the Indian population holds when it comes to investing in cryptocurrency. To do so, a survey was designed using the UTAUT model and was circulated by the means of google forms. A wide range of parameters were considered to avail the maximum possible accuracy for the data collected. Parameters like, the ease of investing crypto, short term and long term benefits, monetary benefits, social benefits were considered. All of these parameters were supposed to be answered on a scale of 5. After collecting all the data, the results were analyzed and evaluated using which the hypothesis made were proved. Keywords: Cryptocurrency, UTAUT, performance expectancy, effort expectancy, perceived monetary benefits, perceived safety, social influence, adoption intension.


1996 ◽  
Vol 39 (2) ◽  
Author(s):  
G. Asch ◽  
K. Wylegalla ◽  
M. Hellweg ◽  
D. Seidl ◽  
H. Rademacher

During the Proyecto de Investigaciòn Sismològica de la Cordillera Occidental (PISCO '94) in the Atacama desert of Northern Chile, a continuously recording broadband seismic station was installed to the NW of the currently active volcano, Lascar. For the month of April, 1994, an additional network of three, short period, three-component stations was deployed around the volcano to help discriminate its seismic signals from other local seismicity. During the deployment, the volcanic activity at Lascar appeared to be limited mainly to the emission of steam and SO2. Tremor from Lascar is a random, «rapid-fire» series of events with a wide range of amplitudes and a quasi-fractal structure. The tremor is generated by an ensemble of independent elementary sources clustered in the volcanic edifice. In the short-term, the excitation of the sources fluctuates strongly, while the long-term power spectrum is very stationary.


2021 ◽  
Vol 10 (3) ◽  
pp. 134-143
Author(s):  
Annisa Yulianti ◽  
Hadi Sasana

 This study aims to analyze the short-term and long-term relationship of increasing the minimum wage in Central Java on employment. The research method used is ECM. The variables of this study include labor, minimum wages, PMDN, and economic growth. The data used are time-series data from 1990-2020. The results show that the minimum wage has a positive and significant relationship to the employment in the long term but not significantly in the short time. PMDN has a negative but significant correlation in the short and long term. At the same time, the variable economic growth has a positive but not meaningful relationship to employment absorption in the long and short term.


2020 ◽  
Author(s):  
Daniel S. Helman

Schizophrenia is a major mental illness with a disease course that is influenced by lifestyle. The risk-benefit ratio for alternative interventions is more favorable than for antipsychotics in long-term treatment. Dietary interventions may target autoimmune features, vitamin or mineral deficiencies, abnormal lipid metabolism, gluten sensitivity or others. Examples of interventions involving diet, physical activity or physical processes, or social interventions including talk therapy exist in the literature. Notwithstanding, the general utility of these types of interventions remains inconclusive, awaiting long-term randomized trials. A perspective that separates the cause of the disease from its symptoms may be helpful in treatment planning and is warranted to distinguish between short-term and long-term recovery goals.


2018 ◽  
Vol 25 (2) ◽  
pp. 169-197
Author(s):  
Mitchell B. Lerner

The election of Donald J. Trump unsettled many areas of U.S. foreign policy, but few more than the nation’s relationship with Korea. This article argues that the Trump administration’s vision for the world represents a stark break from the tradition of liberal internationalism and instead seeks to take the United States down a path that reflects the modern business practices of giant American corporations. A suitable label for this vision, as the following pages will show, is “Walmart unilateralism.” This framework abandons the traditional American policies of nation building and alliances based on shared ideological values. Instead, it embraces a more short-term approach rooted in financial bottom lines, flexible alliances and rivalries, and the ruthless exploitation of power hierarchies. This new approach, this article concludes, may dramatically transform the American relationship with Korea. Walmart unilateralism in Korea almost certainly will have some short-time positive ramifications for the United States, but its larger failure to consider the history and values of the people living on the Korean Peninsula may generate serious long-term problems for the future experience of the United States in the region.


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