Cosmic Background Bose Condensation (CBBC)

Degeneracy effects for bosons are more important for smaller particle mass, smaller temperature and higher number density. Bose condensation requires that particles be in the same lowest energy quantum state. We propose a cosmic background Bose condensation, present everywhere, with its particles having the lowest quantum energy state, ?c/λ, with λ about the size of the visible universe, and therefore unlocalized. This we identify with the quantum of the self gravitational potential energy of any particle, and with the bit of information of minimum energy. The entropy of the universe (～10¹²² bits) has the highest number density (～10³⁶ bits/cm³) of particles inside the visible universe, the smallest mass, ～10^?66 g, and the smallest temperature, ～10^?29 K. Therefore it is the best candidate for a Cosmic Background Bose Condensation (CBBC), a completely calmed fluid, with no viscosity, in a superfluidity state, and possibly responsible for the expansion of the universe.     

Sigseg: a tool for the detection of position and velocity discontinuities in geodetic time-series

The detection of discontinuities in geodetic data is an ever more important topic due to both the influence of discontinuities on the results of models and analyses, and to the very meaning of discontinuities in physical phenomena. We consider and describe a mathematical model, originally formulated for the approximation of images by smooth functions, in one dimension (1D). The model had been designed to smooth the data while preserving and detecting its discontinuities following a variational approach. A second and more complex model for the approximation of images by functions with smooth first derivatives is also available. This second model had been designed to smooth the data while preserving and detecting the discontinuities of the data, but also those of the first derivative. Such interesting features suggest the chance to apply this second model to 1D geodetic data, in particular for the detection of discontinuities and velocity changes in position time-series rather than for signal smoothing. The sigseg (signal segmentation) program implements the two variational models in 1D and is presented with applications to geodetic data. The essential mathematical elements are sketched, and some details on the numerical implementation are given.     

Zonal jets and cyclone–anticyclone asymmetry in decaying rotating turbulence: laboratory experiments and numerical simulations

The problem of zonal jet formation and cyclone–anticyclone asymmetry in decaying rotating turbulence is addressed using both laboratory experiments and numerical simulations with a high-resolution shallow water model in a spherical geometry. Experiments are performed at different Rossby and Froude numbers and applying a rigid wall as meridional boundary in the numerical scheme to mimic the experimental apparatus. The formation of a zonally banded flow pattern, i.e. meridionally confined easterly/westerly jets, has observed; both experimental and numerical results confirmed that this tendency is favoured by high-planetary vorticity gradients. Also, in the experiments characterized by large rotation speeds and small Rossby deformation radius, an initial symmetric distribution of relative vorticity is found to evolve towards a dominance of anticyclonic structures, indicating a breaking of the cyclone–anticyclone symmetry. This aspect has deepened by numerically analysing the sensitivity of the temporal variations of the asymmetry index with respect to the position of the meridional confinement as well as the effect of relaxing the divergence of the fluid (i.e. non-divergent case) to zero. Results suggested that experiments characterized by the higher rotation speed and the lower fluid thickness are better reproduced by a divergent model with a high-latitude meridional boundary.     

Nb-Ta-minerals from the cap de creus pegmatite field,eastern Pyrenees: distribution and geochemical trends

Summary Internal structure and mineralogy facilitate distinction of four main pegmatite types at the eastern end of the Pyrenees. Three main trends in compositional variations in Nb-Ta-Sn-REE-Ti minerals have been established: a regional trend, with Ta/(Ta + Nb) ratio increasing towards the more evolved pegmatites, Mn/(Mn + Fe) being relatively low and increasing only slightly; a single-body trend, with similar enrichment toward the late pegmatite units; a single-crystal trend, with zoning related to both Ta/(Ta + Nb) and Mn/(Mn + Fe) ratios and a tendency toward Ta-enrichment in the late growth stages. The regional geochemical enrichment trends in the Mn/(Mn + Fe) ratios and Ta/(Ta + Nb) are those expected for a beryl-columbite pegmatite type. In a single pegmatite, the evolution depends on the simultaneous growth of other mineral species. Three factors seem to control the development of zoning in columbite-tantalite crystals: availability of Mn, Ta, Fe, Nb, significant differences in solubility between mineral group end members and re-equilibria with late pegmatite fluids.

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Nb-Ta-Minerale aus dem Pegmatit-Feld vom Cap de Creus, östliche Pyrenäen: Verteilung und geochemische Trends

Zusammenfassung Am Ostrand der Pyrenäen können anhand des inneren Aufbaus und der Mineralogie vier Haupttypen von Pegmatiten unterschieden werden. Die Zusammensetzungen von Nb-Ta-Sn-SEE-Ti-Mineralen folgen drei Haupttrends: einem regionalen Trend, bei dem das Verhältnis Ta/(Ta + Nb) zu den höher entwickelten Pegmatiten hin zunimmt, während Mn/(Mn + Fe) relativ niedrig ist und nur leicht zunimmt; einem lokalen (auf das jeweilige Vorkommen beschränkten) Trend mit einer ähnlichen Anreicherung zu den spätpegmatitischen Einheiten hin; einem auf Einzelkristalle bezogenen Trend mit Zonierung in bezug auf die Verhältnisse Ta/(Ta + Nb) und Mn/(Mn + Fe) und einer Tendenz zur T a-Anreicherung in den späten Wachstumsphasen. Die regionalen geochemischen Anreicherungstrends in den Mn/(Mn + Fe)- und Ta/(Ta + Nb)-Verhältnissen entsprechen jenen, wie sie für den Beryll-Columbit-Pegmatit-Typ erwartet werden. In einem einzelnen Pegmatit hängt die Entwicklung vom gleichzeitigen Wachstum anderer Mineral-Spezies ab. Drei Faktoren scheinen die Ausbildung einer Zonierung in Columbit-Tantalit-Kristallen zu kontrollieren: das Angebot an Mn, Ta, Fe und Nb, deutliche Unterschiede in der Löslichkeit der Endglieder von Mineralgruppen und die Iteequilibrierung mit spätpegmatitischen Lösungen.

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With 6 Figures     

A nocturnal atmospheric loss of CH<Subscript>2</Subscript>I<Subscript>2</Subscript> in the remote marine boundary layer

Ocean emissions of inorganic and organic iodine compounds drive the biogeochemical cycle of iodine and produce reactive ozone-destroying iodine radicals that influence the oxidizing capacity of the atmosphere. Di-iodomethane (CH₂I₂) and chloro-iodomethane (CH₂ICl) are the two most important organic iodine precursors in the marine boundary layer. Ship-borne measurements made during the TORERO (Tropical Ocean tRoposphere Exchange of Reactive halogens and Oxygenated VOC) field campaign in the east tropical Pacific Ocean in January/February 2012 revealed strong diurnal cycles of CH₂I₂ and CH₂ICl in air and of CH₂I₂ in seawater. Both compounds are known to undergo rapid photolysis during the day, but models assume no night-time atmospheric losses. Surprisingly, the diurnal cycle of CH₂I₂ was lower in amplitude than that of CH₂ICl, despite its faster photolysis rate. We speculate that night-time loss of CH₂I₂ occurs due to reaction with NO₃ radicals. Indirect results from a laboratory study under ambient atmospheric boundary layer conditions indicate a k _CH2I2+NO3 of ≤4 × 10^?13 cm³ molecule^?1 s^?1; a previous kinetic study carried out at ≤100 Torr found k _CH2I2+NO3 of 4 × 10^?13 cm³ molecule^?1 s^?1. Using the 1-dimensional atmospheric THAMO model driven by sea-air fluxes calculated from the seawater and air measurements (averaging 1.8 +/? 0.8 nmol m^?2 d^?1 for CH₂I₂ and 3.7 +/? 0.8 nmol m^?2 d^?1 for CH₂ICl), we show that the model overestimates night-time CH₂I₂ by >60 % but reaches good agreement with the measurements when the CH₂I₂ + NO₃ reaction is included at 2–4 × 10^?13 cm³ molecule^?1 s^?1. We conclude that the reaction has a significant effect on CH₂I₂ and helps reconcile observed and modeled concentrations. We recommend further direct measurements of this reaction under atmospheric conditions, including of product branching ratios.     

The Hyblean xenolith suite (Sicily): an unexpected legacy of the Ionian–Tethys realm

The extensive study of a great number of deep-seated xenoliths from Tortonian tuff-breccia pipes in the Hyblean area (Sicily) revealed the following fundamental evidence: (1) typical continental crust rocks are completely absent in the entire xenolith suite; (2) mantle ultramafics are more abundant than gabbroids; (3) sheared oxide–gabbros, closely resembling those from oceanic fracture zones, are relatively common; (4) secondary mineral assemblages, compatible with alteration processes in serpentinite-hosted hydrothermal systems, occur both in peridotites and gabbros. Among the products of this hydrothermal activity, organic compounds, having abiotic origin via Fischer–Tropsch synthesis, occur in some hydrothermally altered gabbro and ultramafic xenoliths, as well as in hydrothermal clays. Moreover, the U–Pb dating of hydrothermal zircon grains, hosted in a xenolith of metasomatized tectonic breccia, indicated an Early–Middle Triassic age of the fossil hydrothermal system. Another line of evidence for the oceanic nature of the Hyblean–Pelagian basement is the complete absence of continental crust lithologies (granites, felsic metaigneous, and metasedimentary rocks) in outcrops and in boreholes, and the oceanic affinity of the Tertiary volcanic rocks from the Hyblean Plateau and the Sicily Channel (Pantelleria and Linosa Islands), which lack of any geochemical signature for continental crust contamination. A reappraisal of existing geophysical data pointed out that serpentinites form the dominant lithologies in the lithospheric basement of the Hyblean–Pelagian area down to a mean depth of 19 km, which represents the regional Moho considered as the serpentinization front, marking the transition from serpentinites to unaltered peridotites. On these grounds, we confirm that Hyblean xenoliths contain mineralogical, compositional, and textural evidence for tectonic, magmatic, and hydrothermal processes indicating the existence of fossil oceanic core complexes, in the geotectonic framework of the Paleo–Mesozoic, ultra-slow spreading, Ionian–Tethys Ocean forming the present Ionian–Hyblean–Pelagian domain.     

Ground-based GPS measurements: time behavior from half-hour to years

Ground-based GPS and weather stations time series for the period 2010–2012 of precipitable water vapor (PWV), relative humidity (RH), and surface temperature (T) of half-hourly resolution are analyzed to demonstrate their value for dynamical analyses and weather forecasting. Three sample stations in the USA from the SoumiNet network are considered, which have rather continuous data for the last 3 years and a few missing values. Results for the three stations reveal the following features: (1) PWV time behavior is dominated by the annual cycle superimposed on high-frequency fluctuations with missing daily cycle, indicating a prevailing large-scale transport source of precipitable water at these sites; (2) RH is characterized by the daily cycle and high-frequency variability, while the annual cycle is missing; (3) T mainly varies following the annual and diurnal cycles; and (4) all variables show similar scaling properties of their variance spectra, S(f)?～?f ^–β , with a high-frequency regime of red noise type scaling (β?～?2) up to a day and long-term persistence beyond a week (β?～?0.5), with a week-long frequency interval of transition. Detrended fluctuation analysis of relative humidity indicates a clear long-term persistence scaling covering more than three decades. Implications of these findings on weather forecasting and climate modeling are discussed.     

Geant4 simulations of soft proton scattering in X-ray optics

Low energy protons (< 300 keV) can enter the field of view of X-ray telescopes, scatter on their mirror surfaces at small incident angles, and deposit energy on the detector. This phenomenon can cause intense background flares at the focal plane decreasing the mission observing time (e.g. the XMM-Newton mission) or in the most extreme cases, damaging the X-ray detector. A correct modelization of the physics process responsible for the grazing angle scattering processes is mandatory to evaluate the impact of such events on the performance (e.g. observation time, sensitivity) of future X-ray telescopes as the ESA ATHENA mission. The Remizovich model describes particles reflected by solids at glancing angles in terms of the Boltzmann transport equation using the diffuse approximation and the model of continuous slowing down in energy. For the first time this solution, in the approximation of no energy losses, is implemented, verified, and qualitatively validated on top of the Geant4 release 10.2, with the possibility to add a constant energy loss to each interaction. This implementation is verified by comparing the simulated proton distribution to both the theoretical probability distribution and with independent ray-tracing simulations. Both the new scattering physics and the Coulomb scattering already built in the official Geant4 distribution are used to reproduce the latest experimental results on grazing angle proton scattering. At 250 keV multiple scattering delivers large proton angles and it is not consistent with the observation. Among the tested models, the single scattering seems to better reproduce the scattering efficiency at the three energies but energy loss obtained at small scattering angles is significantly lower than the experimental values. In general, the energy losses obtained in the experiment are higher than what obtained by the simulation. The experimental data are not completely representative of the soft proton scattering experienced by current X-ray telescopes because of the lack of measurements at low energies (< 200 keV) and small reflection angles, so we are not able to address any of the tested models as the one that can certainly reproduce the scattering behavior of low energy protons expected for the ATHENA mission. We can, however, discard multiple scattering as the model able to reproduce soft proton funnelling, and affirm that Coulomb single scattering can represent, until further measurements at lower energies are available, the best approximation of the proton scattered angular distribution at the exit of X-ray optics.     

中国东部诸流域的干旱和湿润期:模式和预测

降水观测记录是近50a来中国九大流域干旱和湿润期时空变化分析的基础.以两年为时间尺度引入标准降水指数(SPI)来分析评价气候变化情景,结果表明黄河流域、长江流域和淮河(或珠江)流域等三个主要的区域表现为低频率变化指数:另外分析显示北方地区自20世纪70年代以来干旱更频繁的出现,在SPI时间序列中呈现负趋势变化.这也许与表征SPI信号的长周期有关(24a和48a周期).与这些长周期一起,也有一些其它方面的因素有助于频谱变化,范围从3a到9a不等.在指数时间序列中这些周期成分的存在为长期预测干旱和湿润期提供了很好的条件.     

Havana: From local experiment to national reform

In April 2011 the Cuban government announced a suite of national reforms with deeper socioeconomic ramifications than the limited liberalizations it permitted in the 1990s. Although unprecedented in revolutionary Cuba, the proposed changes draw on previous efforts to manage decentralization, employment and the informal sector. The paper examines two case studies of prior experimentation with liberalization since 2000 in the municipality of Old Havana and the neighbouring district, Barrio Chino (Chinatown). We argue that the 2011 reforms are informed by specific lessons and insights from these two experiences and also by general development principles advocated by China.