Human sociogeophysics — Phase II (continued): Criticality in the diffusion of ethnicity produces civil society

After a Phase I expansion at a constant population density, the earth's surface —the habitable niche of man — becomes filled. The subsequent global Malthusian constant (birth rate minus death rate) however remains unchanged. A criticality in density is thereupon reached, and a phase transition ensues. The most marked feature of Phase II is an onset of condensations, of settlements in place. The kinematics of Phase II involved (a) continued low growth rate of total population; (b) the continued diffusion of ethnicity with remixing; (c) fluctuating condensations involving local urban densifications; (d) local convective process fluxes (flows) carried on via trade and war rather than simple diffusive flow processes carried on via extensive local migrations; and (e) civilizational flow processes of convection governed by man-made rules for the diffusive transports of matter, energy, action and population.The diffusion of ethnicity continues at an expanded space-time scale. The spatial scale is enlarged to the order of 300 km, with a corollary time scale of 1/2 to 1 millennium. This estimate is based on two physical notions: (a) a stability criterion for the transition, which provides an estimate for the number (density) of neighboring condensed population centers that need be involved in the trade-war convections (on the order of 16) and the range domain for these centers (on the order of 200–300 km); and (b) continuance of the diffusion of ethnicity as marked by a diffusivity relation (d₁ ²/t₁ = d₂ ²/t₂) where d₁ = 50–80 km (prior hunter-gatherer spatial scale), t₁ = 30 years (prior hunter-gatherer time scale), d₂ = 300 km (subsequent settlement spatial scale), so that t₂ (subsequent settlement temporal scale) approximates 500 to 1000 years.While the total human ensemble represents a unitary human culture (in Braudel's term, a world-economy), it also contains a plurality of cultures in the anthropologist's sense, which now continuously diffuse and rediffuse, mix and remix. This continuing diffusion of ethnicity at the longer and larger scales produces longer and larger-scale fluctuations — fluid-like, transitory, large moving — which begin to constitute the politics and economics of civilizations. Trade and war become civilization's macroscopic flows, surplus production and states and empires its macroscopic patterns and forms.     

Human sociogeophysics — Phase I: Explaining the macroscopic patterns of man on earth

The demography of man on earth is treated by a physical model for that forward transport for the subspecies in time. By examining the distribution of man and his Neanderthaler precursor, it is inferred, as a likely hypothesis, that the initial Phase I expansion of man on earth (40,000–15,000 ybp) was at a constant density of about 0.04 persons per sq.km with little or no remixing. We suggest that the nature of the physical process was a diffusion, a random walk process with a diffusive velocity of one roaming range (30 km) per generation, i.e., 1.5 km per year. The physics and physiology of the breeding process permits us to estimate the total earth population, the birth rate b, the death rate d, and the net difference (that is the Malthusian constant K, dP/dt = KP, where K = b-d, P = population, and dP/dt is the rate of change in population).     

Trajectories of ions specularly reflected from non-planar collisionless shocks

An important contribution to the thermalization of the solar wind ions at the Earth's bow shock for high Mach numbers comes from the reflection of a fraction of these ions from the shock. Previous studies have examined the trajectories of the reflected ions assuming the shock to be an infinite plane. In this paper a model is developed to describe the trajectories of particles after reflection for a variety of shock geometries. Of particular interest are the initial conditions which allow the particle to return to the shock with a greater normal velocity than at first encounter, or to return to the shock at all. The effects of the magnetic field direction and the curvature of the shock on particle trajectories are discussed for cylindrical and spherical shock geometries and compared to those for a planar shock.     

Description and General Background to Ships' Logbooks as a Source of Climatic Data

Meteorological observations made on board ships prior to 1854 have until now been overlooked in climatological research largely as a result of the lack of rigorous abstraction and treatment criteria. However, the CLIWOC project has shown that millions of potentially valuable observations have been preserved throughout Europe in the many logbooks that were prepared by officers in the navies of the great powers. Moreover these data can be used and treated in a fashion similar to today's ship-based instrumental observations. The most significant logbook collections are from Spain, the UK, the Netherlands and France. This paper describes the main archives where the logbooks can be found and provides an account of their contents and of the manner in which they were set out. The potential of this source is emphasised by the fact that whilst the CLIWOC project abstracted data for 300,000 days, nearly 90% of the European logbook collections have yet to be examined. This paper concludes with a discussion as to the direction of future studies in this important field.     

Discordant RbSr and PbPb whole rock isochron ages for the Archaean basement of Sierra Leone

Field mapping and structural studies in northern Sierra Leone by an I.G.S. team have established a stratigraphic sequence in this part of the Archaean of the West African Craton. An older “Leonian” granite-greenstone terrain is identified which experienced a tectonic-metamorphic event before the formation of the granite-greenstone terrain which ended with the Liberian tectonic-metamorphic event. Granite gneisses in the Fadugu district with Leonian structures yield statistically acceptable but discordant Pb-Pb and Rb-Sr whole-rock isochron ages of 2959±50 Ma and 2753±61 Ma, respectively (2 σ errors). These ages may be correlated with radiometric ages for the Leonian and Liberian structures elsewhere in Sierra Leone, and it is concluded that the Fadugu Rb-Sr whole-rock isochron has been reset by the Liberian event. The Pb-Pb whole-rock isochron for the Fadugu gneisses and a previously determined (but recomputed and partially checked) Rb-Sr whole-rock isochron age of 2980+80 Ma for granite gneisses from southeastern Sierra Leone provide a definitive age for the Leonian tectonic-metamorphic event at about 2970 Ma. Both the initial ⁸⁷Sr/⁸⁶Sr ratios and present-day first-stage model ²³⁸U/²⁰⁴Pb value for the Leonian granitoids are indistinguishable from mantle values, but do not preclude the possibility that these granitoids were derived from parental material with a short history in the crust or lower crust. The Rb-Sr whole-rock isochron age of 2753+61 Ma for the Fadugu granite gneiss provides a definitive age for the Liberian event in northern Sierra Leone. A succession of rocks older than the Leonian (i.e., older than 2970 Ma) has been identified in the field but not yet dated.     

Ospar 98/3: an environmental turning point or a flawed decision?

While the problems of over-fishing and eutrophication continue largely unchecked, the Ospar Commission, which exists to improve the quality of European seas, requires governments, the public and the oil companies to find 20 billion Pounds to remove millions of tons of steel to demonstrate its commitment to the mantra that 'the seas are not dustbins'. The decision, taken in 1998, was made despite a paucity of evidence to identify the environmental impact redundant rigs create, despite the absence of scientific support to demonstrate that removal is the best practicable environmental option and in the knowledge that the decision had more to do with a green anti-oil agenda than with improving marine quality. It may be shown in the fullness of time not to be in the best interests of the environment. Moreover, and perhaps more importantly, the manner in which the decision was made is lacking in important respects.     

The Disruption of a Small Disc Galaxy by a Massive Elliptical

N-body simulations of the capture of a small disc galaxy by a massive elliptical primary show that tidal forces destroy the inner part of the disc in a brief episode at some critical distance from the centre of the primary. We suggest that this phase may be characterised by chaotic motions in the disc material causing a burst of star formation. Such an event would offer a natural explanation of the colour differences between stars in shells around an elliptical galaxy and those in the galaxy itself. We report a study of orbits in the disc prior to and during its disruption, designed to test this hypothesis. This revised version was published online in July 2006 with corrections to the Cover Date.     

A new quadruple gravitational lens system: CLASS B0128+437

High-resolution MERLIN observations of a newly discovered four-image gravitational lens system, B0128+437, are presented. The system was found after a careful re-analysis of the entire CLASS data set. The MERLIN observations resolve four components in a characteristic quadruple-image configuration; the maximum image separation is 542 mas and the total flux density is 48 mJy at 5 GHz. A best-fitting lens model with a singular isothermal ellipsoid results in large errors in the image positions. A significantly improved fit is obtained after the addition of a shear component, suggesting that the lensing system is more complex and may consist of multiple deflectors. The integrated radio spectrum of the background source indicates that it is a gigahertz peaked spectrum source. It may therefore be possible to resolve structure within the radio images with deep VLBI observations and thus to constrain the lensing mass distribution better.     

Future projections of temperature-related climate change impacts on the railway network of Great Britain

Great Britain’s main line railway network is known to experience various temperature-related impacts, e.g. track buckling and overhead power line sag at high ambient temperatures. Climate change could alter the frequency of occurrence of these impacts. We have therefore investigated the climate change impact on various temperature-related issues, identified during workshops with rail industry specialists, using a perturbed physics ensemble (PPE) of the Met Office’s regional climate model (RCM), HadRM3. We have developed novel approaches to combine RCM data with railway industry knowledge, typically by identifying key meteorological thresholds of interest and analysing exceedance of these out to the 2040s. We performed a statistical analysis of the projected changes for each issue, via bootstrapping of the unperturbed PPE member. Although neither the PPE nor the bootstrapping analysis samples the full range of uncertainty in the projections, they nonetheless provide complementary perspectives on the suitability of the projections for use in decision-making. Our main findings include projected increases in the summertime occurrence of temperature conditions associated with (i) track buckling, (ii) overhead power line sag, (iii) exposure of outdoor workers to heat stress, and (iv) heat-related delays to track maintenance; and (v) projected decreases in the wintertime occurrence of temperatures conditions associated with freight train failure owing to brake problems. For (i), the statistical significance varied with track condition and location; for (ii) and (iii), with location; and for (iv) and (v), projected changes were significant across Great Britain. As well as assessing the changes in climate-related hazard, information about the vulnerability of the network to past temperature-related incidents has been summarised. Combining the hazard and vulnerability elements will eventually support a climate risk assessment for the industry.