Upper stratospheric and mesospheric temperatures derived from lidar observations at Aberystwyth

From lidar observations of relative atmospheric density above Aberystwyth (52.4°N, 4.1°W) upper stratospheric and mesospheric temperatures have been derived for a total of 93 nights between December 1982 and February 1985. Excellent agreement was found between radiances synthesised from these temperatures and those measured by satellite-borne instruments. Summer temperatures showed a smooth and regular variation with altitude and reasonably good agreement with the CIRA (1972) model atmosphere. By contrast, winter temperatures showed a much greater variability with altitude and greater changes from night to night, with the frequent occurrence of a large amplitude wave-like perturbation in the mesosphere with about 15 km vertical wavelength and amplitude about 20K between 60 and 80 km.Pronounced warmings of the stratosphere were observed during the three winters of observation. During the warming event occurring in early February 1983 the stratopause temperature increased to 303K at 43 km, while the major warming event of late December 1984/early January 1985 produced a stratospheric temperature gradient of 16K km⁻¹ between 34 and 36 km. During the latter event a distinct local temperature minimum at 32.6 km was observed on New Year's Eve, this descending to 29 km by the following night and being accompanied by a lowering of the stratopause from 43 to 38.5 km in the same period. These results demonstrate the ability of the present technique to resolve the high stratopause temperatures and steep stratospheric temperature gradients which occur during stratospheric warmings, in marked contrast to the limited resolution achieved by satellite experiments.     

Mesospheric temperatures and the OH layer height as derived from ground-based lidar and OH1 spectrometry

Night-time mesospheric temperatures were simultaneously determined from the Doppler broadening of the D₂ resonance line of atmospheric sodium excited by a laser and from the rotational distribution of the P₁(1), P₁(3) and P₁(4) lines of the OH(3,1) band by an i.r. spectrometer. Both instruments were located at the Andøya Rocket Range (69°N, 16°E). The mesospheric temperature gradient permits determination of the altitude of the OH¹ emitting layer from a comparison of the equivalent layer temperatures calculated from the height-resolved Na Doppler temperatures with the observed OH¹ rotational temperatures. The altitude of the OH¹ layer maximum is determined with an accuracy of ±4 km. For 3 nights in January 1986 the OH¹ emission layer is found near an altitude of 86 km.     

A comparison of low- and mid-latitude D region electron densities derived from ground-based radio data

Electron density profiles, 70–110 km, for almost identical solar zenith angles over Central Europe and over Ahmedabad (India) are compared, avoiding seasonal ‘anomalies’. Low- and mid-latitude profiles agree very well in their structural features, the maximum deviation in magnitude being by a factor of 2 (around 90 km).     

Indications of formation water flow and compartmentalization on the flank of a salt structure derived from salinity and seismic data

Vertical and lateral variations in lithology, salinity, temperature, and pressure determined from wireline LAS logs, produced water samples, and seismic data on the south flank of a salt structure on the continental shelf, offshore Louisiana indicate three hydrogeologic zones in the study area: a shallow region from 0 to 1.1 km depth with hydrostatically pressured, shale‐dominated Pleistocene age sediments containing pore waters with sea water (35 g l^?1) or slightly above sea water salinity; a middle region from 1.1 to 3.2 km depth with near hydrostatically pressured, sand‐dominated Pliocene age sediments that contain pore waters that range from seawater salinity to up to 5 times sea water salinity (180 g l^?1); and a deep section below 3.2 km depth with geopressured, shale‐dominated Miocene age sediments containing pore waters that range from sea water salinity to 125 g l^?1. Salt dissolution has generated dense, saline waters that appear to be migrating down dip preferentially through the thick Pliocene sandy section. Sand layers that come in contact with salt contain pore waters with high salinity. Isolated sands have near sea water salinity. Salinity information in conjunction with seismic data is used to infer fluid compartmentalization. Both vertical and lateral lithologic barriers to fluid flow at tens to hundreds of meters scale are observed. Fluid compartmentalization is also evident across a supradomal normal fault. Offset of salinity contours are consistent with the throw of the fault, which suggests that saline fluids migrated before fault formation.     

Electron paramagnetic resonance of mosaic glasses from the Mediterranean area*

Ancient mosaic glass tesserae sampled from archaeological sites located in the Mediterranean area have been analysed by Inductively Coupled Plasma‐Optical Emission Spectroscopy (ICP‐OES). The aim of the research was to understand the role played by 3d transition metals in the optical properties of such samples. In order to better identify the specific effect of the main chromophorous element, modern samples have been prepared in the laboratory by adding to a colourless base frit controlled concentrations of colouring oxides. Samples with compositional and optical properties similar to the ancient ones have been obtained. For all these modern samples, as well as for all the ancient ones, electron paramagnetic resonance (EPR) measurements have been performed. The features of the EPR spectra could be successfully associated with the presence and abundance of the paramagnetic colouring ions (namely iron, manganese and copper) and to their oxidation states. This could be a basic step towards understanding the provenance and chronological attribution of mosaic glass tesserae.     

Temporal variations of the global lightning activity deduced from the Schumann resonance data

Temporal variations of the global lightning activity were deduced from long-term Schumann resonance (SR) continuous records. The intensities of the horizontal magnetic field component in the vicinity of the first, second, and third SR modes were monitored at Tottori observatory (35.5°N, 134.33°E) from 1968. Variations of the effective source-observer distance were estimated using the ratios of the intensities of individual modes. This allowed us to obtain average diurnal variations of the global lightning activity for each month over a one-year period. The results show that the distances estimated between the field-site and the effective source are very stable, while the temporal changes of the fields and the global lightning intensity derived demonstrate substantial variability.     

Variations of the lower ionosphere parameters measured by the resonance scattering method

This paper presents the results of diagnostics of the lower ionospheric parameters by using the resonance scattering method (RSM) of radio waves on periodic artificial irregularities (PAI). The following ionospheric parameters have been measured by the heating facilities ‘Zimenki’ and ‘Sura’: electron density including the E-F interlayer valley and the lowest height of the ionosphere; the velocity of the vertical wind; the relaxation times of the PAI characterizing coefficients of ambipolar diffusion, and coefficients of attachment and detachment of electrons from negative ions. Variations of these parameters have been considered as a function of height, local time, season, solar activity as well as being induced by passing acoustic-gravity waves and by ionospheric disturbances.     

Diagnostics of the lower ionosphere by the method of resonance scattering of radio waves

Results are presented on measurements of lower ionosphere parameters (electron concentration, coefficient of ambipolar diffusion, etc.) by the method of resonance scattering of radio waves by periodic artificial irregularities. The method of resonance scattering is based on the generation of periodic irregularities in the ionospheric plasma by powerful radio emission and investigation of the characteristics of the back scattering of diagnostic radio waves by these irregularities.     

江苏新沂前沟汉代墓地D1 、D2发掘简报

2018年,徐州博物馆、新沂市博物馆联合对前沟汉代墓地其中两个土墩进行考古发掘,共清理墓葬49座.墓葬形制多样,排列有序,在年代上有一定承袭关系.从墓葬形制和随葬器物推断,墓葬时代在西汉晚期至东汉时期.前沟汉代墓地是一处规模较大的汉代土墩墓群,该墓地发掘为研究徐州地区乃至江苏汉代土墩墓类型提供了新的考古资料.     

A comparison of plasma densities by EISCAT and the Dynasonde from auroral altitudes: evidence of intense structure

Under conditions of moderately-energetic particle precipitation typical of the equatorward side of the auroral oval, plasma densities obtained from routine analysis of EISCAT Common Program data are often a factor 2 to 5 smaller than those suggested by co-located digital ionograms. We consider the reasons for this disagreement, and in particular we reject the implications of diffractive and multiplyrefractive scatter as alternatives to the usual plasma-frequency interpretation of ionogram echoes. We examine the effects of the (5 min and shorter) temporal averaging applied to the EISCAT data and conclude that together with the evidently small size (perhaps as little as 20 km) and high velocity of these structures, this accounts for much, if not all, of the disagreement. We point out the significance of the higher plasma densities in the 100–150 km height range for estimates of Joule and particle heating.     

Current density models of the eastward electrojet derived from ground-based magnetic field and radar measurements

Correlated studies of the eastward auroral electrojet using EISCAT radar data and groundbased magnetic field observations from a meridional chain of five stations have been performed during the years 1987 and 1988. Three different models of current distributions—the line-type, the current sheet and the parabolic model—have been tested for their applicability in estimating the current density of the electrojet. The model employing a parabolic cross-section of the current density provides the best results, both from the magnetic profile and from the comparison of magnetic field and radar current density estimates. Current estimates from magnetic field observations are systematically 15% higher than those from EISCAT readings. This discrepancy has been attributed to the induction effect.     

Firing technique characterization of black-slipped pottery in Praeneste by low field 2D NMR relaxometry

This study was aimed at individuating characteristics related to the pottery’s firing technique of Classical Roman producers, through the low field single-sided NMR relaxometry. The approach is based on a recent method of analysis, the correlation of the longitudinal and transverse NMR relaxation times of a liquid probe (in this case distilled water) filling the porous system of ceramics. The analyzed findings form two homogeneous classes with dating and place of production well established through the producer trademarks. Pottery findings belong to the black-slipped pottery productions of the Latin ancient city of Praeneste between third and second century B.C. and have been attributed to two different ”patriziae” production families: gens Samiaria and gens Trebonia. A further fragment with Greek kylix style, found in the same archaeological area, has also been analyzed, in order to understand if it had been imported from Greece, or made in Praeneste in imitation of the Greek style.     

Seasonal mean structure of the night-time F2 region over Arecibo

Seasonal mean night-time variations of ion and electron temperatures, electron density, ion drift velocity, and light ion composition of the F2 region are derived from incoherent scatter observations at Arecibo based on 19 nights of observation over the latest sunspot minimum years 1974–1976. It is shown that the downward flux of ionization is sufficient to maintain the nocturnal F2 region against recombination at low latitudes. The difference in the electron density decay rate from summer to winter is consistent with the seasonal variation in magnitude of the ionization flux. The mean eastward electric field, which is responsible for any vertical component perpendicular to B, is very small throughout the night. However, the southward electric field, i.e. east-west ion drifts, shows a substantial systematic variation during the night, being southward (eastward ion drifts) before midnight and northward after midnight, with a mean amplitude of 1–2 mVm⁻¹. The H⁺ ion concentration shows a marked seasonal variation. The mean relative concentration of H⁺ ion to electron density at 500 km sometimes exceeds 50% before sunrise in winter. A strong anti-correlation of H⁺ ion concentration with magnetic activity is observed. The observed ion temperatures average about 20–30 K higher than the prediction of the Jacchia (1971) neutral model for the observed range of the 10.7 cm solar flux.     

The effect of population variation on the accuracy of sex estimates derived from basal occipital discriminant functions

Multiple discriminant functions that estimate sex from the dimensions of the basal occipital have been published. However, as there is limited exploration of basal dimension variation between groups, the accuracy of these functions when applied to archaeological material is unknown. This study compares basal dimensions between four known sex-at-death post-medieval European samples and explores how metric differences impact on the accuracy of sex assessment discriminant functions. Published data from St Bride’s, London (n = 146) and the Georges Olivier collection, Paris (n = 68) were compared with new data from the eighteenth to nineteenth century Dutch Middenbeemster sample (n = 74) and the early twentieth century Rainer sample, Romania (n = 282) using independent t tests. The Middenbeemster and Rainer data were substituted into six published discriminant functions derived from the St Bride’s and the Georges Olivier samples, and the results were compared to their known sex. Multiple statistically significant differences were found between the four groups. Of the six discriminant functions tested, five failed to reach the published accuracy and fell below chance. In addition, even where the samples were statistically comparable in means, trends for difference also impacted the accuracy of discriminant functions. Enough variation in basal occipital dimensions existed in the European groups to decrease the accuracy of sex estimation discriminant functions to unusable. Possible inter-observer error, varying genetic, socioeconomic, and geographical factors are likely causes of dimension variation. This research further highlights the dangers of using sex estimation discriminant functions on samples that differ to the original derivative population and demonstrates the need for more rigorous testing.     

A method of determining horizontal structure of the ionosphere from backscatter ionograms

We have developed a technique lor oblique backscatter sounding (OBS) ionogram inversion as a diagnostic tool for the horizontally inhomogeneous structure of the ionosphere. Input data for the method include the leading edge of a backscalter ionogram that is measured through soundings in a given direction, and the vertical electron density profile measured over the sounding station or over some other site lying in the sounding direction. The method may be useful for reconstructing the two-dimensional electron density distribution in a vertical plane aligned with the direction of sounding. The inverse problem has been solved using the Newton Konlorovich method and the Tikhonov regularization method. The algorithm we have developed was tested against model data, that is, OBS ionograms synthesized using geometrical optics calculations for different models of the inhomogeneous ionosphere. Test results demonstrate that our method converges reliably, is stable to measurement errors and provides a good accuracy of reconstruction of inhomogeneous structures with scales of 100 2000 km. This indicates that this method shows promise as an operative remote diagnostic tool for ionospheric irregularities of natural and artificial origin.     

Processing ochre in the Middle Stone Age: Testing the inference of prehistoric behaviours from actualistically derived experimental data

The increase in the presence of ‘ochre’ in African Middle Stone Age contexts has been employed, together with changes in human biology and behaviour, to support the hypothesis that ‘modern’ cognitive abilities arose in Africa. The consistent exploitation of ochre is interpreted as evidence for colour symbolism, a proxy for the origin of language and a defining aspect of ‘modern’ human behaviour. That humans attached considerable symbolic value to red ochres in particular is illustrated by ethnographic examples. Research has shown that wear patterns indicative of abrasive processing methods prevail, but many archaeological specimens also exhibit wear traces not derived from grinding or scraping alone. Building on former research, I present here the results of an experimental study devised to infer the methods employed to extract powder from ochre during the African Middle Stone Age. The prospect of ascertaining at least some of the likely uses to which ochre may have been put, is also explored. I conclude that functional data derived from actualistic experiments can be used to enhance our understanding of some aspects of prehistoric behaviour.     

Seasonal and tidal variations of neutral temperatures and densities in the high latitude lower thermosphere measured by EISCAT

Measurements of ion temperature, ion-neutral collision frequency and ion drift in the E-region from the period December 1984 to November 1985 are used to derive neutral temperatures, densities and meridional winds in the altitude intervals 92–120 km, 92–105 km and 92–120 km, respectively. Altitude profiles of temperature and density and their seasonal variations are compared with the CIRA 1972 and MSIS 1983 models and the effects of geomagnetic activity are demonstrated. Semi-diurnal tidal variations in all three parameters are derived and the comparison with lower latitude measurements is discussed.     

The movement of the poem in the 1960s: from circle and line to zero and one,from concretion to computation

ABSTRACT

Poetic form in the 1960s in Britain, and elsewhere, was affected by trans-disciplinary and trans-cultural influences that came fully into focus after the end of the Second World War. These were substantially iterated and theorized throughout the 1950s, paving the way for radical experiments in language during the following decade. Drawing on Paul Celan’s observation that poetry maintains itself ‘at its own extremity’ (expanded by Lyon [1983. “Poetry and the Extremities of Language: From Concretism to Paul Celan.” Studies in 20th Century Literature 8 (1): Article 5. Accessed September 20, 2016. doi:10.4148/2334-4415.1131] and Klink [2000. “You. An Introduction to Paul Celan.” The Iowa Review 30 (1): 1–18. http://ir.uiowa.edu/iowareview/vol30/iss1/2], this article considers movement in the form and language of poetry in the post-war period. It looks at some specific examples of how this became manifest in Britain and at traversal connections to developments within other disciplines, not least in scientific and technological domains.     

Human ecological niches and ranges during the LGM in Europe derived from an application of eco-cultural niche modeling

We apply eco-cultural niche modeling (ECNM), an heuristic approach adapted from the biodiversity sciences, to identify habitable portions of the European territory for Upper Paleolithic hunter-gatherers during the Last Glacial Maximum (LGM), circumscribe potential geographic extents of the Solutrean and Epigravettian technocomplexes, evaluate environmental and adaptive factors that influenced their distributions, and discuss this method's potential to illuminate past human–environment interaction. Our ECNM approach employed the Genetic Algorithm for Rule-Set Prediction (GARP) and used as input a combination of archaeological and geographic data, in conjunction with high-resolution paleoclimatic simulations for this time frame. The archaeological data consist of geographic coordinates of sites dated by Accelerator Mass Spectrometry to the LGM and attributed to the Solutrean and Epigravettian technocomplexes. The areas predicted by ECNM consistently outline the northern boundary of human presence at 22,000–20,000 cal BP. This boundary is mainly determined by climatic constraints and corresponds well to known southern limits of periglacial environments and permafrost conditions during the LGM. Differences between predicted ecological niches and known ranges of the Solutrean and Epigravettian technocomplexes are interpreted as Solutrean populations being adapted to colder and more humid environments and as reflecting influences of ecological risk on geographic distributions of cultures.