Inertial Cycle Research Articles

Combined Effects of Liquefaction-Induced Lateral Spreading and Superstructure Inertial Loads on Pile Foundations

Pile foundations in sloping or gently sloped liquefiable soils are often subjected to a combination of inertial and lateral spreading loads. Current design codes vary significantly in terms of the methods used to analyze and design piles that are subjected to combined loading. The results from a full-scale shake table test on a 0.25-m-diameter reinforced concrete pile in gently sloping ground are used in this study to back-calculate the inertial loads, the kinematic loads, and the interaction between inertial and kinematic loads during seismic loading. It was found that large pile strains developed after liquefaction was triggered. The maximum pile strains (and curvatures) at shallow depths within the nonliquefiable crust were correlated with maximum inertial loads in the upslope direction that were resisted by a crust load applied in the downslope direction, indicating an out-of-phase interaction. The maximum pile strains (and curvatures) at deeper locations below the loose liquefiable sand were correlated with the maximum inertial loads in the downslope direction but without any resistance or driving load from the crust (i.e., no lateral spreading load during peak downslope inertial cycles). The lack of crust load during the downslope inertial cycles was attributed to the pile head outrunning the crust displacement, causing the pile to be pushed into a gap that had formed on the downslope front of the pile. The findings of this study contribute a data point to a wide range of inertial and kinematic interaction factors proposed by other studies and highlight the site- and project-dependency of interactions between inertial and kinematic loads.

Cyclin D3 drives inertial cell cycling in dark zone germinal center B cells.

During affinity maturation, germinal center (GC) B cells alternate between proliferation and somatic hypermutation in the dark zone (DZ) and affinity-dependent selection in the light zone (LZ). This anatomical segregation imposes that the vigorous proliferation that allows clonal expansion of positively selected GC B cells takes place ostensibly in the absence of the signals that triggered selection in the LZ, as if by "inertia." We find that such inertial cycles specifically require the cell cycle regulator cyclin D3. Cyclin D3 dose-dependently controls the extent to which B cells proliferate in the DZ and is essential for effective clonal expansion of GC B cells in response to strong T follicular helper (Tfh) cell help. Introduction into the Ccnd3 gene of a Burkitt lymphoma-associated gain-of-function mutation (T283A) leads to larger GCs with increased DZ proliferation and, in older mice, clonal B cell lymphoproliferation, suggesting that the DZ inertial cell cycle program can be coopted by B cells undergoing malignant transformation.

Effects of Beetroot Juice Supplementation on a 30-s High-Intensity Inertial Cycle Ergometer Test.

Background: Beetroot juice (BJ) is rich in inorganic nitrates and has proved effective at increasing blood nitric oxide (NO) levels. When used as a supplement BJ has shown an ergogenic effect on cardiorespiratory resistance exercise modalities, yet few studies have examined its impact on high intensity efforts. Objective: To assess the effects of BJ intake on anaerobic performance in a Wingate test. Methods: Fifteen trained men (age 21.46 ± 1.72 years, height 1.78 ± 0.07 cm and weight 76.90 ± 8.67 kg) undertook a 30-s maximum intensity test on an inertial cycle ergometer after drinking 70 mL of BJ (5.6 mmol NO3−) or placebo. Results: Despite no impacts of BJ on the mean power recorded during the test, improvements were produced in peak power (6%) (p = 0.034), average power 0–15 s (6.7%) (p = 0.048) and final blood lactate levels (82.6%) (p < 0.001), and there was a trend towards a shorter time taken to attain peak power (−8.4%) (p = 0.055). Conclusions: Supplementation with BJ has an ergonomic effect on maximum power output and on average power during the first 15 s of a 30-s maximum intensity inertial cycle ergometer test.

The Zombie Zone

The Zombie Zone Rob Latham (bio) Zone One. Colson Whitehead. Doubleday. http://knopfdoubleday.com. 336 pages; cloth, $25.95, paper, $15.00. With hordes of the undead shambling across a blighted media landscape, zombie apocalypses are a dime a dozen these days, but when a major literary novelist turns his attention to the form, it’s an indication that this cultural meme has reached either maturity or senescence. Whitehead, author of five previous novels including The Intuitionist (1999) and Sag Harbor (2009), is one of the finest prose craftsmen currently practicing, and something about the topic here brings out the full measure of his extraordinary lyricism. Gorgeous sentences are devoted to gruesome scenes of flesh eating and brain splattering—as well as to brooding meditations on cultural inertia and social collapse. Whitehead is obviously a fan of the zombie genre; in an interview with The Atlantic, he acknowledged that, as a teenager, he was “demonically attached… to the first George Romero trilogy,” and Zone One features a series of studied homages to those movies: the famous line of dialogue from Night of the Living Dead (1968) about the zombies being “all messed up” is quoted twice, while that film’s scenario of a clutch of survivors besieged in a rural farmhouse is briefly reenacted. Yet it is clear that his true touchstone is Romero’s second zombie movie, Dawn of the Dead (1978), where the farmhouse is converted into a suburban shopping center and the apocalypse into an allegory of mindless consumerism. As one of that film’s characters comments when asked why the creatures are thronging to the mall, “this was an important place in their lives,” a judgment Whitehead echoes in his caustic depiction of New York as a “dead city continu[ing] its business in mirthless parody.” His satirical target is broader than Romero’s, however, amounting to nothing less than an indictment of corporate capitalism and the political regime that coddles it. On the one hand, even before the plague that has converted most of the global population into the walking dead (“skels” in the novel’s jargon), there was something zombified about human culture, especially in its Westernized mass-media incarnation. Several references are made to a popular pre-plague sitcom, probably a version of Friends (1993–2004) that was influential in luring young outsiders to the metropolis, “powerless before the seduction of the impossible apartment that the gang inexplicably afforded on their shit-job salaries, unable to resist the scalpel-carved and well-abraded faces.” As the protagonist—nicknamed Mark Spitz thanks to a daring aquatic escape—grimly observes, their “underdeveloped cultural immune systems” left them susceptible to being “infected by reruns.” This infection lingers in the form of a subset of zombies called “stragglers” who remain trapped in inertial cycles of routine, usually centering on work or leisure activities, and who seem untroubled by the cannibal hunger that drives the skels: “They didn’t know you were there. They kept watching their movies.” Before the cataclysm, Mark Spitz had been centrally involved in the consumer industries himself, haunting social media sites on behalf of a “coffee multinational” in order “to sow product mindshare and nurture feelings of brand intimacy.” Small wonder he continues to have nightmares of the pre-plague world as one in which “all the supporting characters were dead…the panoply of citizens in the throes of their slow decay.” On the other hand, the survivor culture that is patiently attempting to re-establish itself—by mounting paramilitary expeditions to eradicate the skels, such as the eponymous Zone One in lower Manhattan—seems impelled by a desire simply to reinstate neoliberal capitalism. The provisional government, based in Buffalo, has been jumpstarting the stalled economy by awarding defense contracts, subsidizing new growth industries (e.g., portable kerosene canisters), selling official sponsorships, and designing plucky logos in a vigorous PR campaign to rebuild the public trust. “The new era of reconstruction was forward-looking, prudent, attentive to the small details that will dividend in the years to come.” It was, Mark Spitz reflects, “almost as if the culture was picking up where it left off” in a vast project of temporal gentrification: The...

Inertial currents in the Indian Ocean derived from satellite tracked surface drifters

Satellite-tracked surface drifters were used to analyze the characteristics of inertial currents in the tropical Indian Ocean. The drifters were drogued at 15 m depth and had wind-produced slips less than 0.1 % of the wind speed. The rotary spectra of surface velocity components indicated the significance of inertial currents. They are circular (rotary coefficient >0.5), highly intermittent and contribute up to 46 % to the total kinetic energy of the surface flow field. Events of inertial activity, either triggered by the passage of atmospheric disturbances or by the local fluctuations in the atmospheric pressure (winds), did not last for more than 4 to 5 inertial cycles. The observed inertial frequency exhibited a shift towards the red end of the spectrum by 12 %. Cyclonic storm induced inertial events even at a location 300 km away from it.

Resonant Wind-Driven Mixing in the Ocean Boundary Layer

The role of resonant wind forcing in the ocean boundary layer was examined using an ocean large-eddy simulation (LES) model. The model simulates turbulent flow in a box, measuring ∼100–300 m on a side, whose top coincides with the ocean surface. Horizontal boundary conditions are periodic, and time-dependent wind forcing is applied at the surface. Two wind forcing scenarios were studied: one with resonant winds, that is, winds that rotated at exactly the inertial frequency (at 45°N), and a second with off-resonance winds from a constant direction. The evolution of momentum and temperature for both cases showed that resonant wind forcing produces much stronger surface currents and vertical mixing in comparison to the off-resonance case. Surface wave effects were also examined and found to be of secondary importance relative to the wind forcing. The main goal was to quantify the main processes via which kinetic energy input by the wind is converted to potential energy in the form of changes in the upper-ocean temperature profile. In the resonant case, the initial pathway of wind energy was through the acceleration of an inertially rotating current. About half of the energy input into the inertial current was dissipated as the result of a turbulent energy cascade. Changes in the potential energy of the water column were ∼7% of the total input wind energy. The off-resonance case developed a much weaker inertial current system, and consequently less mixing because the wind acted to remove energy after ∼¼ inertial cycle. Local changes in the potential energy were much larger than the integrated values, signifying the vertical redistribution of water heated during the summer season. Visualization of the LES results revealed coherent eddy structures with scales from 30–150 m. The largest-scale eddies dominated the vertical transport of heat and momentum and caused enhanced entrainment at the boundary layer base. Near the surface, the dominant eddies were driven by the Stokes vortex force and had the form of Langmuir cells. Near the base of the mixed layer, turbulent motions were driven primarily by the interaction of the inertial shear with turbulent Reynolds stresses. Bulk Richardson number and eddy diffusivity profiles from the model were consistent with one-dimensional model output using the K-profile parameterization.

Evolution Through Group Selection.

An outline of `animal dispersion' hypothesis Food as a limiting resource Food is not always the limiting factor The three trophic industries Exploiting seeds, fruit, and nectar General relationships affecting consumers The red grouse Territory and food More field experiments Food and breeding success General factors that react on territory size Do inertial cycles play a part in population change? A review and commentary on the red grouse research Cycles in population structure Evolution in structured populations Population structuring as a group adaptation Population structuring in the invertebrate phyla Population structuring and homeostasis in platyhelminth parasites Group selection at different organizational levels Some problems solved.

Circulations of the West Pacific Jet Stream

Abstract The jet stream of the west Pacific is a very steady feature of the winter circulation, with almost continuousintensification over East China and Japan and weakening in the central Pacific. In this study the National Meteorological Center spectral forecast model with normal mode initialization is used as a tool to provide diagnostic elements in a region of nonstandard data sources. Cross sections transverse to the jet stream in its intensification zone show a deep single-celled direct solenoidal circulation around a single frontal zone to be producing large increases of kinetic energy. Farther east, in the central Pacific, a strong indirect solenoidal circulation produces a strong decrease of kinetic energy. The irrotational wind components at jet stream levels are suggestive of an inertial cycle as part of the jet stream dynamics. A simple model of a modified inertial cycle is integrated in which the geostrophicwind is allowed to vary as a function of the ageostrophic flow transverse to the jet a...

Time spectra and cross‐spectra of kinetic energy in the planetary boundary layer

AbstractTemporal spectra and cross‐spectra of the three turbulent wind components for meso‐synoptic scales at 250 m vertical intervals in the planetary boundary layer are presented. The data were derived from hourly simultaneous balloon ascents from a 5‐point grid at Hay, New South Wales, Australia (lat. 34 ½S), during the Wangara expedition. The spectra indicate a meso‐scale gap for u (eastward component of wind) and v (northward component). The computed w‐spectra suggest that no marked gap is present. For periods less than 1 day the u‐ and v‐spectra, with a correction applied for high frequency noise, fall off approximately as n−2·6, where n is the frequency, and this result appears to be invariant with height within and just above the planetary boundary layer. The corrected w‐spectra exhibit n−1 dependency in this frequency range. The uv, uw, and vw cospectra also show only small contributions on the meso‐scale (periods less than a day) compared to the synoptic scale, indicating that meso‐scale motions may not have to be explicitly modelled in atmospheric general circulation models. An inertial peak is found for u and v but the w‐spectra show a diurnal peak. The phase angles showed that u and v were in approximate quadrature at the inertial frequency, demonstrating the existence of the inertial cycle. Tests for horizontally two‐dimensional isotropy indicated that the turbulence did not obey this simplification.