Universal law for waiting internal time in seismicity and its implication to earthquake network

In their paper (Europhys. Lett., 71 (2005) 1036), Carbone, Sorriso-Valvo, Harabaglia and Guerra showed that "unified scaling law" for conventional waiting times of earthquakes claimed by Bak et al. (Phys. Rev. Lett., 88 (2002) 178501) is actually not universal. Here, instead of the conventional time, the concept of the internal time termed the event time is considered for seismicity. It is shown that, in contrast to the conventional waiting time, the waiting event time obeys a power law. This implies the existence of temporal long-range correlations in terms of the event time with no sharp decay of the crossover type. The discovered power-law waiting event-time distribution turns out to be universal in the sense that it takes the same form for seismicities in California, Japan and Iran. In particular, the parameters contained in the distribution take the common values in all these geographical regions. An implication of this result to the procedure of constructing earthquake networks is discussed.Comment: 21 pages, 5 figure

Radiation budget, ground thermal regime and hydrological balance of a low arctic tundra basin, Coppermine River, Northwest Territories

The effects of slope, aspect and vegetation cover on the radiation balance and active layer thermal regime of arctic tundra were investigated during the summer of 1999 and the spring of 2000. The study site is located at Daring Lake, N.W.T (64°52\u27N, 111°35\u27W) in the Slave Geological Province of the Coppermine River Basin. A sub-basin 14 ha in area and with approximately 30 meters of relief was intensely monitored for hydrological radiation and energy balance components. Initiation of active layer development and subsequent thawing was earlier and more pronounced on predominantly west facing slopes due to increased receipt of incoming solar radiation. Late summer active layer depths were the greatest on west-facing slopes as compared to north-and east-facing slopes (\u3e170 cm. 84.0 ±21.7 cm. 49.2 ±0.8 cm respectively). Incoming shortwave radiation values were extrapolated from the met site to various basin sites taking slope and aspect into account. Spatial and diurnal variations in albedo were minimal within the Kakawi Lake Basin. As well, surface temperature measurements varied little from site to site causing the long wave radiation balance to remain relatively constant. Incoming shortwave radiation was determined to control diurnal fluctuations in the net radiation balance on a daily and seasonal basis but represented less than one half (41%) of the radiative supply to the surface. Ground heat flux increased downslope on west- and north-facing hillslopes corresponding with an increase in active layer development during the summer season. Conversely, basal flux out of the active layer to the underlying permafrost decreased downslope. The sensible heat flux varied least with depth between the study sites but accounted for a significant proportion of the ground flux at sites with deeper active layers. Active layer depths at peat dominated, east-facing hillslope sites were only 59% of the average depth on west- and north-facing slopes primarily due to the high water content and reduced thermal conductivity of peat soils. Latent heat is largest at the beginning of the thaw season when there is rapid active layer development but is later reduced as ground thaw slackens. Kakawi Lake Basin precipitation input, outflow and lake water level were recorded daily throughout the 36 day study period while evaporation was estimated based on a study conducted in a nearby basin. Lateral inflow from catchment hillslopes was determined to the dominant component of the Kakawi Lake Basin hydrological balance for the 1999 study period. Peat dominated areas were disconnected throughout much of the study period but drained as a single source during rainfall events

Diffusion and pulsations in slowly rotating B stars

Diffusion in cool B stars of the main sequence has been shown to strongly affect opacities and convection in cool B stars of the main sequence. We show here that diffusion in B stars maintains or enhances the excitation of pulsations in these stars. This result conflicts with observations as cool B stars that show evidence of diffusion, the HgMn stars, are stable to the current detection level. We discuss possible implications of this discrepancy for the models.Comment: 4 pages, 1 figure, in Element stratification in stars: 40 years of atomic diffusio

A renormalization group model for the stick-slip behavior of faults

A fault which is treated as an array of asperities with a prescribed statistical distribution of strengths is described. For a linear array the stress is transferred to a single adjacent asperity and for a two dimensional array to three ajacent asperities. It is shown that the solutions bifurcate at a critical applied stress. At stresses less than the critical stress virtually no asperities fail on a large scale and the fault is locked. At the critical stress the solution bifurcates and asperity failure cascades away from the nucleus of failure. It is found that the stick slip behavior of most faults can be attributed to the distribution of asperities on the fault. The observation of stick slip behavior on faults rather than stable sliding, why the observed level of seismicity on a locked fault is very small, and why the stress on a fault is less than that predicted by a standard value of the coefficient of friction are outlined

Motor Learning And Adaptation In People With Knee Osteoarthritis And Chronic Pain

Osteoarthritis (OA) affects an estimated 50 million people in the US, and approximately 43% have limitations in daily function due to arthritis pain.3 Individuals with knee osteoarthritis (OA) have heightened sensitization to pain2,5 as well as reduced strength, diminished function and quality of life1 that prompts them to seek care from health care providers. Physical therapists commonly work with patients to improve function and quality of life by helping them learn to move without pain. Unfortunately, chronic pain causes changes to the nervous system that may impact the ability to learn new ways but the extent to which chronic pain affects motor learning in people with chronic pain is largely unknown. We are investigating the influence of chronic pain on the rate of learning a new motor task using the “broken escalator” paradigm and we present kinematic and electromyographic (EMG) data from four subjects illustrating motor learning in two people with knee OA and two healthy age matched control subjects.https://dune.une.edu/com_studpost/1001/thumbnail.jp