Sentences with phrase «periodic variations of»

Radial velocity observations from observing runs in 2000 and 2004 reveal a periodic variation of 3.30 ± 0.02 d, which is consistent with the previously determined value of 3.3125 ± 0.0002 d.

Not exact matches

Naturally - produced radio waves exhibit patterns of changes in wavelength that are due to random or periodic variation over time.

Cowart noted that periodic rinses always cause desensitization where mixtures do not, leading her to conclude: «Much of the apparent masking of taste intensity in the presence of oral irritation is not directly related to the irritation level but is sensitive to procedural variation.»

Scientists have linked the periodic changes in our planet's rotation rate (which determines day length) to various factors, such as tides and interactions between Earth's inner layers, but a good deal of the variation remains unexplained.

David Thomson, Carol Mclennan and Louis Lanzerotti of AT&T Bell Laboratories in Murray Hill, New Jersey, claim that the flow of particles in the solar wind shows periodic variations on timescales of a few minutes, which exactly match the periods of vibrations of the Sun's core (Nature, vol 376, p 139).

In acoustics interference of two waves with slightly different frequencies creates a beat, or a periodic variation in volume.

A month later, follow - up observations with the Lovell radio telescope in Cheshire, UK, revealed periodic variations in the pulsar's signals, indicating the existence of an orbiting companion with the mass of a planet.

A periodic variation in the number of solar neutrinos detected on Earth may hold information about subtle changes in temperature at the very centre of the Sun.

This suggests that the Galaxy originally contained little of the so - called heavy elements (elements beyond helium in the periodic table); and the variation of chemical composition with age suggests that heavy elements must have been produced more rapidly in the Galaxy's early history than now.

The problem is that in many cases investors pay a recurring annual fee of anywhere from 0.2 % to 1.5 % of assets for a one - time setup of a portfolio pie - chart (frequently with small variations from the adviser's «moderate» allocation template), followed by periodic rebalancing and reports.

Where the natural variation claims fail is in their presumption of periodic oscillatory behavior.

The evidence points in the direction that they are not chaotic, so unless anyone can prove they are chaotic, most of the scientific community (i.e. the IPCC, et al.) are of the opinion that they are not chaotic, but are generated by predictable periodic shifts (such as variation of axial tilt or distance from the sun).

We show in this study that even short - periodic natural variations of climate forcing can lead to significant long - term variability in the climate system.

Based on the GISP2 ice core proxy record from Greenland it has previously been pointed out that the present period of warming since 1850 to a high degree may be explained by a natural c. 1100 yr periodic temperature variation (Humlum et al., 2011).

Uncertainties in the regression models and fits used to distinguish between periodic variations and trends in the different databases appear to be a significant source of uncertainty in the estimates of longterm trends.

Further experiments will explore the influence of periodic forcings such as the quasi biennial oscillation (QBO) in equatorial winds and the cyclical variation of solar radiation.

Nevertheless, the simplistic notion that climate variations consist of an analytic trend plus multidecadal periodic cycles hidden by higher - frequency «weather noise» remains endemic among those who feature themselves as «climate scientists.»

An approximately periodic variation was noted in the data, in the rough form of a rectified sine wave.

This topology was stable for the first 5 months, followed by a dual coronal hole distribution producing 13.5 - day periodic variations up to the end of the observation period.

The regular occurrence of small peaks every ten to eleven years reflects the window's transition through the periodic variations commonly attributed to the «solar cycle».

One important feature that plays a role in these variations is the periodic change of atmospheric and oceanic circulation patterns in the tropical Pacific region, collectively known as El Niño — Southern Oscillation (ENSO) variation»

But the turnover suggests strongly that the pause has the same «cause» as the related «pause» from the 40's to the 70's — the downward half - cycle of the 67 year periodic variation that I have no explanation for.

While the idea that future climate is unpredictable is correct in the main, that is the case because of the general lack of truly periodic variations (over time - spans of human proportions).

There is now very strong evidence that the root cause of these cycles lies in periodic variations in the earth's rotation axis and orbit around the sun.

Detailed investigation of DTR - CR flux relationships from an expanded station - based dataset, and reanalysis data found no significant associations between either the DTR and periodic (11 - year and 1.68 - year) solar variations, or FD events at global or regional scales (Laken et al. 2012c).

While he was never successful in doing so, his work led him to the discovery of a link between the periodic pressure variations in the Indian Ocean, and those between the eastern and western Pacific, which he termed the «Southern Oscillation».

Indeed, the way in which climatic forcing is expressed in natural systems is not universal, with both spatial (local, regional and latitudinal) and temporal (periodic pulses and seasonal cycles) variations in pH and temperature that are sufficient to affect the direction (positive through to negative) and severity of effect depending on timing and context [110].

Although it is clear that further attention is required in defining and characterizing the aspects of this variation (e.g. frequency and amplitude [44,65]-RRB- that lead to differences in species responses, a more immediate empirical challenge is to characterize and separate the effects of periodic, stochastic and / or cyclical natural variations [61] from directional change imposed by long - term climatic forcing.

While the Earth's atmosphere has seen higher levels of carbon dioxide than it does now, as well as higher temperatures and far greater sea levels, those instances were due to natural drivers of climate change, such as periodic variations in the planet's orbit and in solar energy output.

«Figure 2 shows the temporal variation of the two dominant spectral components, 23.5 yr... and 102 yr... These components are not strictly periodic; they are strongly amplitude and phase modulated.»