Ethnicity as a cause of migration in Eastern Europe

Migration within and from Eastern Europe has recently risen as a topic of significance on the European political agenda. One aspect of this complex migration matrix relates to ethnic unrest. This paper examines the scale and spatial ramifications of this movement on a part of the continent recently freed from communist rule.An attempt is made to divide the ethnic quilt of Eastern Europe into those countries with few such problems and those with many. It is possible then to define areas of active migration (hot spots) from those of potential migration (inflammable spots) based on predictions from the current situation.Active ethnic migration results from the present political/military instability in the western Balkans, where refugees have left for other parts of Europe to escape the present Croat-Serb-Muslim conflict. War escalation could encourage potential ethnic migration from Kosovo, the Sandzak and Vojvodina regions,and Macedonia within the former Yugoslavia. Future disquiet elsewhere could stimulate ethnic groups such as the Turks in Bulgaria,and the Hungarian minorities in Slovakia and Romania to join this migration movement scenario.     

Cu 2p absorption spectroscopy as a probe for the site occupancy of (ZnxCu1−x)WO4 solid solution

The solid solution sanmartinite (ZnWO₄)—cuproscheelite (CuWO₄) has been studied using Cu 2p X-ray absorption spectroscopy. While a single L₃ absorption peak is observed for CuWO₄, two distinct L₃ absorption peaks with a separation of ～0.8 eV are observed for the intermediate samples in the solid solution. The two peaks represent distinct Cu sites: one with all CuO₆ next nearest neighbours in the (Cu,Zn)O₆ chains, another having at least one ZnO₆ next nearest neighbour. Both sites show a linear increase in covalency as a function of increasing Cu-content. The relative intensities of the two absorption peaks is dependent upon the Cu-content and has been used to model the site occupancies. The results reveal that the local structural effects can be associated with a composition-dependent structural phase transition from P2/c (ZnWO₄) to P $\bar 1$ (CuWO₄). Deviations from a single-site model are explained in terms of the local environments, and evidence for site preferences and local clustering are explored.     

Prediction of the occurrence of Related Strong Earthquakes in Italy

In the seismic flow it is often observed that a Strong Earthquake (SE), is followed by Related Strong Earthquakes (RSEs), which occur near the epicenter of the SE with origin time rather close to the origin time of the SE. The algorithm for the prediction of the occurrence of a RSE has been developed and applied for the first time to the seismicity data of the California-Nevada region and has been successfully tested in several regions of the world, the statistical significance of the result being 97%. To date it has been possible to make five successful forward predictions, with no false alarms or failures to predict.The algorithm is applied here to the Italian territory, where the occurrence of RSEs is a particularly rare phenomenon. Our results show that the standard algorithm is successfully directly applicable without adjustment of the parameters. Eleven SEs are considered. Of them, three are followed by a RSE, as predicted by the algorithm, eight SEs are not followed by a RSE, and the algorithm predicts this behaviour for seven of them, giving rise to only one false alarm. Since, in Italy, often the series of strong earthquakes is relatively short, the algorithm has been extended to handle such a situation. The result of this experiment indicates that it is possible to attempt to test a SE, for the occurrence of a RSE, soon after the occurrence of the SE itself, performing timely preliminary recognition on reduced data sets. This fact, the high confidence level of the retrospective analysis, and the first successful forward predictions, made in different parts of the World, indicates that, even if additional tests are desirable, the algorithm can already be considered for routine application to Civil Defence.     

Automatic equipment to monitor groundwater radon

Prototype instrumentation, able to automatically measure groundwater radon content variations, is presented. The equipment is made of stainless steel and has spherical valves with automatic and pneumatic control. The deemanation of the gases from the water is obtained by evacuating a suitable expansion chamber. The instrumentation can make discrete sampling ranging from 1 per hour to 1 per 99 hours. The equipment was tested in the laboratory: the efficiency was measured by means of a²⁶⁶Ra solution. A mean value of (0.65±0.07) count/s/Bq was obtained. A calibration test was carried out by comparing countings from the automatic equipment with those obtained by the standard laboratory cell. Results of an operational check over a period of approximately one year indicate that variations in radon at the calibration site are attributable more to meteorological than to tectonic causes.     

Isotope and trace element evidence for three component mixing in the genesis of the North Luzon arc lavas (Philippines)

Post-3Ma volcanics from the N Luzon arc exhibit systematic variations in ⁸⁷Sr/⁸⁶Sr (0.70327–0.70610), ¹⁴³Nd/¹⁴⁴Nd (0.51302–0.51229) and ²⁰⁸Pb^*/²⁰⁶Pb^* (0.981–1.035) along the arc over a distance of about 500 km. Sediments from the South China Sea west of the Manila Trench also exhibit striking latitudinal variations in radiogenic isotope ratios, and much of the isotopic range in the volcanics is attributed to variations in the sediment added to the mantle wedge during subduction. However, Pb-Pb isotope plots reveal that prior to subduction, the mantle end-member had high 8/4, and to a lesser extent high 7/4, similar to that in MORB from the Indian Ocean and the Philippine Sea Plate. Th isotope data on selected Holocene lavas indicate a source with unusually high Th/U ratios (4.5–5.5). Combined trace element and isotope data require that three end-members were implicated in the genesis of the N Luzon lavas: (1) a mantle wedge end-member with a Dupal-type Pb isotope signature, (2) a high LIL/HFS subduction component interpreted to be a slab-derived hydrous fluid, and (3) an isotopically enriched end-member which reflects bulk addition (<5%) of subducted S China Sea terrigenous sediment. The ⁸⁷Sr/⁸⁶Sr ratios in the volcanics show a restricted range compared with that in the sediments, and this contrasts with ¹⁴³Nd/¹⁴⁴Nd and ²⁰⁸Pb^*/²⁰⁶Pb^*, both of which have similar ranges in the volcanics and sediments. Such differences imply that whereas the isotope ratios of Nd, Pb and Th are dominated by the component from subducted sediment, those of Sr reflect a larger relative contribution from the slab-derived fluid.     

Cesstibtantite—a geologic introduction to the inverse pyrochlores

Summary The crystal structure of cesstibtantite has been solved from diffractometer data collected on samples from Leshaia, Russia and the Tanco pegmatite, Manitoba. Cesstibtantite from the Leshaia pegmatite (type locality) hasa 10.515(2) Å, space groupFd3m, composition Cs_0.31(Sb_0.57Na_0.31Pb_0.02Bi_0.01)_O.91(Ta_1.88Nb_0.12)₂(O_5.69[OH, F]_0.31)₆(OH, F)_0.69, Z 8; its structure was refined toR 3.8,wR 4.3% using 96 observed (F > 3[F]) reflections (MoK). Cesstibtantite from the Tanco pegmatite hasa 10.496(1) Å, space groupFd3m, composition (Cs_0.22K_0.01)_0.23(Na_0.45Sb_0.39Pb_0.14· Ca_0.06Bi_0.02)_1.06(Ta_1.95Nb_0.05)₂(O_5.78[OH,F]_0.22)₆(OH,F)_0.55,Z 8; its structure was refined toR 3.9w R 3.7% using 104 observed reflections. Cesstibtantite differs from the normal pyrochlores in that it contains significant amounts of very large cations such as Cs. As these cations are too large (^VIII[r] > 1.60 Å) for the conventional [8]-coordinated A site, they occupy the [18]-coordinated site, which normally contains monovalent anions. Natural cesstibtantite samples are non-ideal in that both Cs and monovalent anions occur at the site; thus cesstibtantite is intermediate to thenormal pyrochlores (with only monovalent anions at the site) and theinverse pyrochlores (with only large cations at the site).

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Cesstibtantit—eine geologische Einfiihrung in die inversen Pyrochlore

Zusammenfassung Die Kristallstruktur von Cesstibtantit wurde auf der Basis von Diffraktometerdaten von Proben von Leshaia, Russland and dem Tanco Pegmatit, Manitoba, gelöst. Cesstibtantit aus dem Leshaia Pegmatit (Typlokalität) hat a 10.515(2) Å, RaumgruppeFd3m, die Zusammensetzung CS_0.31(Sb_0.57Na_0.31Pb_0.02Bi_0.01)_0.91(Ta_1.88Nb_0.12)₂· (O_5.69OH, F_0.31)₆(OH, F)_0.69 Z 8; die Struktur wurde aufR 3.8,wR 4.3% verfeinert unter Benützung von 96 beobachteten Reflexen. Cesstibtantit vom Tanco Pegmatit hat a 10.496(1) Å, RaumgruppeFd3m, die Zusammensetzung (Cs_0.22K_0.01)_0.23(Na_0.45· Sb_0.39Pb_0.14Ca_0.06Bi_0.02)_1.06(Ta_1.95Nb_0.05)₂(O_5.78OH,F_0.22)₆(OH,F)_0.55,Z 8; seine Struktur wurde aufR 3.9wR 3.7% auf der Basis von 104 beobachteten Rettexen verfeinert. Cesstibtantit unterscheidet sich von normalen Pyrochloren insofern, als er signifikante Mengen von sehr großen Kationen, wie z.B. Cs enthält. Da these Kationen zu groß sind (^VIII r 1.60 Å) für eine konventionelle [8]-koordinierteA Stelle, nehmen she die [18]-koordinierten Positionen ein, welche normalerweise monovalente Anionen enthalten. Natürliche Cesstibtantitproben sind nicht ideal insofern als sowohl Cs als auch monovalente Anionen in der Position vorkommen. Somit ist Cesstibtantit intermediär zu den normalen Pyrochloren (mit nur monovalenten Anionen auf der Position) and den inversen Pyrochloren (mit ausschließlichen großen Kationen an der Position).

     

Late Quaternary palaeolimnology of a tropical marl lake: Wallywash Great Pond,Jamaica

Wallywash Great Pond (17° 57 N, 77° 48 W, 7 m a.s.l.) is the largest perennial lake in Jamaica. It occupies a fault trough within the karstic White Limestone. The Great Pond is a hardwater lake with a pH of 8.2–8.6 and an alkalinity of 3.6–3.9 meq 1^–1. Its chemistry is strongly influenced by the spring discharge from the limestone. The lake water is subject to degassing, evaporation and bicarbonate assimilation by submerged plants and algae, resulting in marl precipitation. A 9.23 m core (WGP2), taken from a water depth of 2.8 m, was analysed for magnetic susceptibility, loss-on-ignition, carbonate content, mole % MgCO₃ in calcite, and stable isotopes in the fine carbonate fraction. The chronology is based on ten¹⁴C and four U/Th dates. Four main sediment types alternate in the core: marl; organic, calcareous mud; organic mud or peat; and earthy, brown, calcareous mud. The marls represent periods of wet/warm climate during sea-level highstands and the organic deposits, shallower, swampy conditions. In contrast, the brown, calcareous muds were laid down when the lake was dry or ephemeral. The last interglacial (120 000- 106 000 yr BP) is represented by three distinct marl units. After a dry interval, stable, wet/warm conditions set in from 106 000 to 93 000 yr BP. A dry/cool climate prevailed between 93 000 and at least 9500 yr BP. Three subsequent cycles of alternating wet and dry conditions culminated in flooding of the basin by the Black River during the late Holocene. These recent events cannot be accurately dated by¹⁴C due to significant and temporally-variable inputs of dead carbon from the springs.     

Theoretical infrared spectra of some model polycyclic aromatic hydrocarbons: effect of ionization

In order to test the hypothesis of ionized polycyclic aromatic hydrocarbons (PAHs) as possible carriers of the UIR bands, we realized a computational exploration on selected PAHs of small dimension in order to identify which changes ionization would induce on their IR spectra. In this study we performed ab initio calculations of the spectra of neutral and positively ionized naphthalene, anthracene, and pyrene. The results are significantly important. The frequencies in the cations are slightly shifted with respect to the neutral species, but no general conclusion can be reached from the three molecules considered. By contrast, the relative intensities of most vibrations are strongly affected by ionization, leading to a much better agreement between the calculated CH/CC vibration intensity ratios and those deduced from observations.     

The inverse planetary problem: a numerical treatment

The so-called inverse planetary problem can be stated as follows: given the distances from the centre, masses, and radii of (say) three planets of a planetary system, find the optimum polytropic index, mass, and radius of their star, and also other quantities of interest, which depend either explicitly or implicitly on the foregoing ones (e.g., central and mean density, central and mean pressure, central and mean temperature, etc.). It is hereafter tacitly assumed that the system is opaque with respect to observations concerning periods of planetary otbits; hence, we cannot have any relevant estimates due to the well-known period laws. In the present paper, the inverse planetary problem is treated numerically on the basis of the so-called global polytropic model, developed recently by the first author.     

Quasi-periodical structures in the galaxy populations: mass and luminosity functions for the cluster galaxies

A search and estimation of the statistical significance of the quasi-periodical structures (QPS) has been carried out: for the luminosity function of the galaxies in a few rich clusters; for the integrated mass function of galaxies in the superclusters identified via = 21 cm observations. Some statistically significant QPS have been revealed. The periods for these structures are in agreement between each other, at this basis the hypothesis has been proposed that an effect of the QPS at the level of galaxies has some universal character. Frequency doubling has been discovered for these QPS.