On Quantum Mechanical Aspects of Microtubules

We discuss possible quantum mechanical aspects of MicroTubules (MT), based on recent developments in quantum physics.We focus on potential mechanisms for `energy-loss-free' transport along the microtubules, which could be considered as realizations of Fr\"ohlich's ideas on the r\^ole of solitons for superconductivity and/or biological matter. By representing the MT arrangements as cavities,we present a novel scenario on the formation of macroscopic (or mesoscopic) quantum-coherent states, as a result of the (quantum-electromagnetic) interactions of the MT dimers with the surrounding molecules of the ordered water in the interior of the MT cylinders. We suggest specific experiments to test the above-conjectured quantum nature of the microtubular arrangements inside the cell. These experiments are similar in nature to those in atomic physics, used in the detection of the Rabi-Vacuum coupling between coherent cavity modes and atoms. Our conjecture is that a similar Rabi-Vacuum-splitting phenomenon occurs in the MT case.Comment: 26 pages LATEX (minor typos corrected no effect on conclusions

Seismic methods for monitoring underground nuclear explosions, an assessment of the status and outlook [Book Review]

This optimistic assessment of the status and outlook for the use of seismic methods to monitor underground nuclear explosions is timely, comprehensive, and competent. It is valuable for anyone interested in monitoring of underground nuclear explosions, whether seismologist or not, and gives background as well as current information necessary for adequate understanding of the problem. It is not a scientific treatise, but a consensus with a collection of scientific opinions from which the consensus was derived. In general it is clearly written--there is a certain amount of confusion introduced because the seismological discussion is primarily carried out in terms of magnitude, whereas the consensus statement only discusses yield. The study group responsible for the report consisted of a group of seismologists from Canada, Czechoslovakia, France, India, Japan, Romania, Sweden, the Union of Soviet Socialist Republics, the United Kingdom and the United States of America (Constantinescu, Ericsson, Herrin, Karnik, Mechler, Miyamura, Pasechnik, Press, Thirlaway, Whittam, Varghese). Dr. D. Davies, the Rapporteur, was responsible for much of the work of compiling the report

Seismic Study of an Oceanic Ridge Earthquake Swarm in the Gulf of California

Detailed seismic investigation of an unusually intense earthquake swarm which occurred in the northern Gulf of California during March 1969 has provided new information about seismic processes which occur on actively spreading oceanic ridges and has placed some constraints on the elastic wave velocities beneath them. Activity during this swarm was similar to that of a foreshock-mainshock-aftershock sequence, but with a ‘mainshock’ composed of over 70 events with magnitudes between 4 and 5.5 occurring in a 6-hr period about a day after swarm activity was initiated. ‘Aftershocks’, including many events greater than magnitude 5, continued for over two weeks. Near-source travel-time data indicate all sources located are within 5–10 km of each other and that hypocentres are confined to the upper crust. Teleseismic P-delays for rays travelling beneath this ridge may be interpreted in terms of an upper mantle with compressional velocities 5–10 per cent less than normal mantle to a depth of 200 km. Average apparent stresses for all swarm events studied are very similar, show no consistent pattern as a function of time, and are close to values obtained from other ridges. The focal mechanism solution shows a large component of normal faulting. An apparent non-orthogonality of nodal planes common to this mechanism solution and to normal faulting events on other ridges disappears when the indicated low upper mantle velocities beneath the source are taken into account. A survey of recent seismicity (post 1962) in the northern Gulf suggests seismic coupling across about 200 km between adjacent inferred spreading ridge segments. Surface waves from these Gulf Swarm earthquakes have amplitudes from one to two orders of magnitude greater than Northern Baja California events with similar short period body wave excitation

Regional variations of source properties in southern California estimated from the ratio of short- to long-period amplitudes

The ratio of short- to long-period amplitude is expressed in terms of apparent stress, rigidity times energy over moment (μE_G/M_0), for 277 earthquakes in California. A map showing the apparent stresses is compiled. In general, the Mendocino and San Andreas faults as well as the Gulf of California area are regions of large surface-wave excitation and little short-period radiation (low apparent stress). Away from the main fault zones, the apparent stresses tend to be higher. Regions of conspicuously low surface-wave excitation (high apparent stress) are the Laguna Salada-Sierra Juarez region in northern Baja California, the California-Nevada border region north of Bishop, and the region associated with the bend of the San Andreas between San Bernardino and San Gorgonio Mountain. A detailed comparison of earthquakes with accurately-known depths at Parkfield and Borrego Mountain indicates two important differences in apparent stresses between these two source regions. The apparent stress at all depths is larger at Borrego Mountain than at Parkfield, and it increases with depth at Borrego Mountain, whereas it remains constant at all depths at Parkfield. The explanation for the variation of surface-wave excitation (apparent stress) is not known for certain, but it could be related to variations in true stress

Self-assembly of iron nanoclusters on the Fe3O4(111) superstructured surface

We report on the self-organized growth of a regular array of Fe nanoclusters on a nanopatterned magnetite surface. Under oxidizing preparation conditions the (111) surface of magnetite exhibits a regular superstructure with three-fold symmetry and a 42 A periodicity. This superstructure represents an oxygen terminated (111) surface, which is reconstructed to form a periodically strained surface. This strain patterned surface has been used as a template for the growth of an ultrathin metal film. A Fe film of 0.5 A thickness was deposited on the substrate at room temperature. Fe nanoclusters are formed on top of the surface superstructure creating a regular array with the period of the superstructure. We also demonstrate that at least the initial stage of Fe growth occurs in two-dimensional mode. In the areas of the surface where the strain pattern is not formed, random nucleation of Fe was observed.Comment: 6 pages, 3 figure

Seismic moment, stress, and source dimensions for earthquakes in the California-Nevada region

The source mechanism of earthquakes in the California‐Nevada region was studied using surface wave analyses, surface displacement observations in the source region, magnitude determinations, and accurate epicenter locations. Fourier analyses of surface waves from thirteen earthquakes in the Parkfield region have yielded the following relationship between seismic moment, M_0 and Richter magnitude, M_L: log M_0 = 1.4 M_L + 17.0, where 3 < M_L < 6. The following relation between the surface wave envelope parameter AR and seismic moment was obtained: log M_0 = log AR_(300) + 20.1. This relation was used to estimate the seismic moment of 259 additional earthquakes in the western United States. The combined data yield the following relationship between moment and local magnitude: log M_0 = 1.7 M_L + 15.1, where 3 < ML < 6. These data together with the Gutenberg‐Richter energy‐magnitude formula suggest that the average stress multiplied by the seismic efficiency is about 7 bars for small earthquakes at Parkfield and in the Imperial Valley, about 30 bars for small earthquakes near Wheeler Ridge on the White Wolf fault, and over 100 bars for small earthquakes in the Arizona‐Nevada and Laguna Salada (Baja California) regions. Field observations of displacement associated with eight Parkfield shocks, along with estimates of fault area, indicate that fault dimensions similar to the values found earlier for the Imperial earthquake are the rule rather than the exception for small earthquakes along the San Andreas fault. Stress drops appear to be about 10% of the average stress multiplied by the seismic efficiency. The revised curve for the moment versus magnitude further emphasizes that small earthquakes are not important in strain release and indicate that the zone of shear may be about 6 km in vertical extent for the Imperial Valley and even less for oceanic transform faults

Excitation of mantle Love waves and definition of mantle wave magnitude

A study is made of the excitation of mantle Love waves of 100 seconds period as a function of magnitude. 153 measurements of Love wave spectral density for earthquakes since 1930 ranging in magnitude from 6.0 to 8.9 are used to determine an excitation curve. The observations were first corrected to a standard distance of 90°. The excitation curve supports earlier results for mantle Rayleigh waves and, for strike-slip motion, an earlier curve for seismic moment versus mantle-wave magnitude. For dip-slip motion, the moments should be multiplied by a factor of about 2 1/2. A definition of mantle wave magnitude M_M, is set up, and the largest earthquake since 1930 found on this scale is the Alaskan earthquake of March 28, 1964 where M_M = 8.9. Other comparably large earthquakes, M_M = 8.8, were the Kamchatka earthquake of November 4, 1952 and the Chilean earthquake of May 22, 1960. It is suggested that mantle-wave magnitudes be used as a diagnostic aid in estimating the Tsunami potential of earthquakes

Excitation of mantle Rayleigh waves of period 100 seconds as a function of magnitude

The excitation of mantle Rayleigh waves of 100 seconds period as a function of magnitude is studied using data from 91 earthquakes in the magnitude range 5.0 to 8.9. The data were recorded on a wide variety of instruments including Milne-Shaw horizontal pendulums and modern long-period high-gain inertial seismographs. The larger earthquakes studied range in time from 1923 to 1964. Mantle Rayleigh wave amplitudes are corrected to a distance of 90° and plotted as a function of surface wave magnitude. The data are compared with theoretical curves based on a moving source model and two statistical models discussed by Aki. It is concluded that for large earthquakes the source may be approximated by a point couple which propagates a distance given approximately by the length of the aftershock zone

Exceptional ground accelerations and velocities caused by earthquakes

This project aims to understand the characteristics of the free-field strong-motion records that have yielded the 100 largest peak accelerations and the 100 largest peak velocities recorded to date. The peak is defined as the maximum magnitude of the acceleration or velocity vector during the strong shaking. This compilation includes 35 records with peak acceleration greater than gravity, and 41 records with peak velocities greater than 100 cm/s. The results represent an estimated 150,000 instrument-years of strong-motion recordings. The mean horizontal acceleration or velocity, as used for the NGA ground motion models, is typically 0.76 times the magnitude of this vector peak. Accelerations in the top 100 come from earthquakes as small as magnitude 5, while velocities in the top 100 all come from earthquakes with magnitude 6 or larger. Records are dominated by crustal earthquakes with thrust, oblique-thrust, or strike-slip mechanisms. Normal faulting mechanisms in crustal earthquakes constitute under 5% of the records in the databases searched, and an even smaller percentage of the exceptional records. All NEHRP site categories have contributed exceptional records, in proportions similar to the extent that they are represented in the larger database

Complexity of energy release during the Imperial Valley, California, earthquake of 1940

The pattern of energy release during the Imperial Valley, California, earthquake of 1940 is studied by analyzing the El Centro strong motion seismograph record and records from the Tinemaha seismograph station, 546 km from the epicenter. The earthquake was a multiple event sequence with at least 4 events recorded at El Centro in the first 25 seconds, followed by 9 events recorded in the next 5 minutes. Clear P, S, and surface waves were observed on the strong motion record. Although the main part of the earthquake energy was released during the first 15 seconds, some of the later events were as large as M = 5.8 and thus are important for earthquake engineering studies. The moment calculated using Fourier analysis of surface waves agrees with the moment estimated from field measurements of fault offset after the earthquake. The earthquake engineering significance of the complex pattern of energy release is discussed. It is concluded that a cumulative increase in amplitudes of building vibration resulting from the present sequence of shocks would be significant only for structures with relatively long natural period of vibration. However, progressive weakening effects may also lead to greater damage for multiple event earthquakes