Range ambiguity effects in Barker-coded multipulse experiments with incoherent scatter radars

A Barker-coded multipulse is the best of the classical modulations when high spatial resolution is needed in incoherent scatter measurements. Unfortunately, this type of modulation generates range ambiguities which reduce the quality of data. In this paper, range ambiguity functions for an EISCAT experiment, ESLA-T4, are displayed. A method of eliminating the ambiguities in data analysis is developed and its applicability is demonstrated. It is found that the method can remove the effects of the range ambiguities in the lower part of the E-region, but above 120 km altitude the correction is not sufficient. The residual of the fit is reduced by an order of magnitude. The changes in the temperatures are a few Kelvin at the lowest altitudes and a few tens of Kelvin between 110 and 120 km.     

Incoherent scatter spectral measurements of the summertime high-latitude D-region with the EISCAT UHF radar

Measurements of incoherent scatter spectra from the auroral D-region were obtained during the summer of 1985 using a sophisticated pulse-to-pulse correlation technique with the EISCAT UHF radar. The spectral width variations with altitude are interpreted in terms of ion-neutral collision frequency, neutral temperature, mean positive ion mass and negative ion number density. Close agreement with predictions of currently available atmospheric models is obtained, except for a narrow layer around 86 km altitude. This layer showed evidence of increased positive ion mass for most of the experiment, and for short intervals indicated a mean ion mass close to 200 a.m.u. It is suggested that the layer is composed of proton hydrates in the vicinity of a structured noctilucent cloud, and that the index of hydration is occasionally large.     

Further effects of charged aerosols on summer mesospheric radar scatter

In an earlier paper, we showed that charged aerosols play a crucial role in enhancing radar echoes from the summer polar mesosphere through reduced diffusion turbulent scatter and dressed aerosol scatter (Cho et al., 1992a). Here, we explore the effects of charged aerosols on radar scatter through ‘fossil’ turbulence and electron density depletion layers. We find that the former can produce radar scatter even after the decay of neutral gas turbulence, while the latter, which are probably produced by the scavenging of free electrons by ice particles, are a candidate for causing partial reflection or Fresnel scatter. Furthermore, we examine the mutual aerosol interaction restriction on dressed aerosol scatter more closely. We find that a high ambient electron density and low aerosol number density are needed for effective dressed aerosol scatter to occur. We then show that very small (less than 1 nm radii), negatively charged aerosols enhance electron diffusivity, and thus inhibit radar scatter. Also, ice aerosol sedimentation, in the light of the reduced diffusion theory, leads us to conclude that the statistical peak in Polar Mesospheric Summer Echoes (PMSE) power should be located between the mean mesopause and the average noctilucent cloud (NLC) height, which agrees with observations. Finally, we invoke time lags in the ice particle formation cycle to account for the observed non-correlation between PMSE and NLC occurrence.     

Ground penetrating radar survey of a prehistoric site in southern Italy

In this paper, we present and discuss the results of a ground penetrating radar (GPR) study carried out in an area of southern Italy where a karst cave with prehistoric remains was found. The aim of the study involved the imaging of the subsurface stratigraphy, both inside and outside the cave, in order to assist archaeologists in an excavation programme.The survey grid comprised 18 intersecting GPR profiles. Problems associated with the use of the GPR within a cave environment are highlighted and the data processing sequence designed to extract useful geo-archaeological signatures is described. Interpretation of the radar sections was controlled by the excavation of two trenches (inside and outside the cave), allowing detailed outlining the complex stratigraphy and the reconstruction of Palaeolithic and Neolithic subsurface horizons.     

The effects of Class I and II sized bovids on macrofracture formation and tool displacement: Results of a trampling experiment in a southern African Stone Age context

Abstract

In this paper we follow from previous experiments that assessed the formation of macrofractures on hunting weapons and trampled tools, and present the results of a new trampling experiment. This new experiment examined the relationship between small bovid trampling and the formation of macrofracture types on replicated stone and bone tools. We also recorded the resulting displacement of the tools in order to assess the relationship between tool morphology and displacement. Three tool types with dimensions similar to southern African archaeological tools were used. The results suggest that small frequencies of certain impact macrofractures occur on tools subject to trampling forces. These frequencies are, however, lower than those generally recorded during hunting experiments. Tool morphologies and fracture combinations are also shown to be important variables in macrofracture analyses. These results contribute to a growing body of experimental data dealing with the relationship between postdepositional processes and macrofracture formation on artifacts.     

Backscatter responses and resolution considerations in archaeological side-scan sonar surveys: a control experiment

The backscatter responses of submerged archaeological material remain poorly understood. To address this, a control experiment was conducted in Belfast Lough during July and August 2001. A selection of material and targets was arranged on the seabed in varying orientations, in an attempt to replicate the situation found on a range of archaeological sites where material is exposed on the seafloor. Repeat side-scan sonar surveys of the control array were conducted at variable ranges and fish heights to examine the backscatter responses and resolution of three commercially available side-scan sonar systems. Results indicate that the electro-acoustic specification of the pulse length and the beam angle of the acoustic sources govern the theoretical resolution of side-scan data. Backscatter data from the control experiment indicate both organic (wood and leather) and inorganic (metals, ceramics, glass and varying aggregate and ballast grades) natural and man-made materials can be imaged using side-scan sonar and a wide variety of archaeological material types and concentrations may be differentiated by their backscatter responses.     

Near-surface imaging of a buried foundation in the Western Desert,Egypt, using space-borne and ground penetrating radar

ALOS/PALSAR L-band full polarimetric data have been used to detect and characterize a well-defined geometric target hidden under sand deposits in the Western Desert of Egypt. This buried object is rectangular in shape with very straight boundaries and encloses an area of 500 m². Inside the rectangular area there is a perfectly circular feature of approximately 53 m² area. High and medium resolution optical satellite images (WorldView-2, ALOS/AVNIR-2) and field investigation confirm that the topography of the study area is relatively flat and completely covered by dry sand. The electromagnetic wave scattering behavior of the detected buried object was measured by decomposing the scattering matrix of ALOS/PALSAR full polarimetric data into Entropy-Alpha (H/α) and Freeman and Durden decompositions. Furthermore, a combination of unsupervised classification algorithms and Constant False-Alarm Rate (CFAR) edge detection was performed on the polarimetric data which revealed a well-defined geometric shape with straight borders. These borders have high α angles with low entropy, which physically means double bounce scattering mechanism with low randomness and is very similar to that of an urban scatterer, indicating that the detected target might be a buried wall-like foundation of a man-made structure. Moreover, 28 ground penetrating radar (GPR) profiles were acquired using a 270 MHz shielded antenna to validate the satellite radar remote sensing results. The GPR profiles reveal very clear hyperbolic shapes at 1.5 m depth with one of them showing a large hyperbolic shape-like structure, which might indicate the presence of a buried foundation. Thus the site might have significance to archaeological studies of the Western Desert, particularly previous human occupation and the sources of water for such habitation.     

Determination of the influence of soil parameters and sample density on ground-penetrating radar: a case study of a Roman picket in Lower Bavaria

Ground-penetrating radar (GPR) surveys are very much influenced by the site-specific physical properties, soil parameters and the sample density of the radar pulses. According to the electromagnetic theory, the transmission and reflection of electromagnetic waves is dominated by the conductivity, dielectric permittivity and the soil moisture. Therefore, it is advisable to measure these parameters in advance of a GPR survey. Commonly, this is not possible directly with the standard common-offset GPR arrays. To overcome this problem, we adapted and applied a direct method called time-domain reflectometry to a selected case study of the Roman picket Hienheim at the Raetischer Limes in Lower Bavaria. Furthermore, we present some important results relating to the profile spacing and orientation of GPR surveys and the site-specific soil parameters. The location and the identification of the archaeological features were successful by all geophysical methods. However, the application of all these geophysical methods like magnetometry, resistivity and GPR in addition with aerial photography and Airborne Laserscanning exemplifies the advantages of an integrated survey to achieve a comprehensive result of an archaeological site. The Roman picket of Hienheim shows up differently in all results, as each one traces the archaeological remains according to a specific physical parameter. Resistivity and radar are best to resolve buried stone structures like the walls of the picket or stone-filled ditches. In contrary, magnetometry benefits of the magnetic contrast between the limestone walls and the surrounding soil.     

Worlds in Mind: the Experience of an Outside World in a Community of the Finisterre Range of Papua New Guinea

This paper deals with how the Yupno's mental image of proper settlement patterns has been changed through the experience of an ‘outside world’. The Yupno inhabit a rugged, extremely remote, mountainous region of the Eastern Finisterre Range in the Madang Province of Papua New Guinea. Teptep is the administrative centre. The region is one of the last unexplored areas of Papua New Guinea. The old Yupno grew up in an isolated world, which was bounded both externally (they knew only their own valley) and internally (the fenced-in dwelling house was the centre of the settlement structure). After the Second World War, however, the valley was ‘opened’: schools were established and some younger Yupno left their valley to visit the cities of Madang and Lae. This experience of the ‘outside world’ changed the mental image of their own settlement territory. When asked to draw their own area, i.e. to externalise their mental image in the sense of Piaget, the Yupno without ‘outside’-experience (the old men and the children without school education) drew a closed, usually oval world with the Yupno river at its centre (the valley as the ‘world’), whereas those who had ‘outside’-experience drew an open, rectangular map laden with details.     

Slag inclusions in iron objects and the quest for provenance: an experiment and a case study

Slag inclusions are found within most archaeological bloomery iron artefacts and are remainders of slag created during the smelting and smithing processes. Although they are widely believed to provide data with the potential for provenancing iron artefacts, previous slag inclusion studies have mostly proven inconclusive. The main aim of the work reported here is to analyse experimental smelting and smithing assemblages (including ore, furnace lining, fuel and slag), to compare these to slag inclusions in the resulting bloom and worked objects, and then explore the relationships between ore, slag and slag inclusions. This study has revealed that the composition of slag inclusions most closely relates to the smelting slag produced, whereas provenance to a specific ore would be difficult due to the chemical variability derived from furnace lining, fuel and any fluxes used. Some compounds in the slag inclusions are particularly affected during smithing of the artefact, i.e. those present in the sand flux and fuel used. However, trends are observed in the K₂O/MgO, MnO/SiO₂, Al₂O₃/SiO₂, Al₂O₃/MgO, Al₂O₃/K₂O and Al₂O₃/CaO ratios that allow comparison between slag inclusions and smelting slag in these experiments, and may therefore be used during other provenancing attempts. The knowledge gained from the experimental assemblages was subsequently applied to an archaeological case study, examining objects from the 900 Cal BC smithing site of Tel Beth-Shemesh, Israel and the 930 Cal BC smelting site of Tell Hammeh, Jordan. The analyses suggest that none of the artefacts examined derived from the Hammeh smelting system.     

Bighorn hunting,resource depression,and rock art in the Coso Range,eastern California: a computer simulation model

The extraordinary record of prehistoric rock art depicting tens of thousands of animal images in the Coso Range of eastern California provides an opportunity to study the relationship between aboriginal hunting, forager ecology, bighorn prey population levels, and the production of rock art. We review archaeofaunal evidence that the Coso desert bighorn sheep population was strongly depleted during the Newberry era after 1500 B.C. We discuss the dating of the rock art and show a correlation between bighorn depletion and increased rock art production. These data are consistent with the arrival of Numic foragers ca. A.D. 600 who competed with the Coso Pre-Numics and eventually terminated the Coso rock art tradition. An ecological predator-prey computer simulation of the human populations (Numic and Pre-Numics), the sheep population, and the rock art “population”, demonstrates these proposed interconnections and gives a reasonable fit to the observed rock art production rate.     

Modeling agricultural potential in Chaco Canyon during the Bonito phase: a predictive geospatial approach

This study presents a geospatial analysis of surficial hydrology and geomorphology and their relationship to potential agricultural productivity in order to better understand the economic role of water in Chaco Canyon during the Bonito Phase (ca. AD 850–1150). Defined as the Natural Agricultural Suitability Analysis, the foundation of this study is a hierarchical geospatial analysis that integrates six key natural factors: slope, soil texture, soil depth, non-catastrophic overbank flooding potential, drainage flow length, and drainage proximity and flow potential. These factors are combined through a raster weighted overlay function to generate composite suitability map that offers a testable proxy for variability in relative agricultural potential during the Bonito Phase at Chaco. The rationale for including this set of natural factors is based largely on ethnographic and modern agricultural studies, but the predictive model differs from previous studies of agricultural potential in that it is independent of the specific archaeological distribution of evidence of agriculture in the study area. The results of this analysis suggest that previous models of Chacoan agricultural productivity have underestimated local production capacity. Previous studies have focused solely on floodplain contexts, whereas this study points to a more comprehensive and geographically distributed use of the landscape.     

着力构建城乡一体党建工作新格局

构建城乡一体党建工作新格局,充分发挥党建工作在统筹城乡发展中的思想政治引领和组织保证作用,是党建工作落实科学发展观的必然要求。当前要着力解决进一步明确基本思路、健全组织体系、加强对党员的动态管理、推进城乡人才双向流动、建立城乡基层组织互助机制以及加大基层党建工作投入力度等六个主要问题。     

Social and political trust in Istanbul and Moscow: a comparative analysis of individual and neighbourhood effects

Aiming to bring local context into studies of social capital, our study uses samples of 4006 individuals in Istanbul and 3476 in Moscow using a comparable questionnaire. The stratification of each city's neighbourhoods on the basis of socio-economic characteristics provided the basis for the sampling. Using a multilevel modelling procedure, we show both that locality matters (neighbourhood effect proved significant) and that social capital may indeed be constituted in very particular ways in illiberal democracies such as Russia and Turkey. Social and political trust are frequently thought to contribute to social capital – that is, to provide social resources upon which individuals or groups may draw for their political efficacy. Trust in fellow citizens in Istanbul exhibits a positive relationship to associational activities (joining clubs etc.), while in Moscow social trust can be explained predominantly in terms of (lower) socio-economic status. At the same time, important similarities emerged between the two cases. For social trust, in both cities the 'cosmopolitanization thesis', which holds that those who associate more widely are also more trusting of fellow citizens, generally applied. Further, in both cities, residents with lower socio-economic status (though in Moscow this is complicated by education) and lower likelihoods of engagement in direct political action were more trustful of parliament . While this is the opposite of what we have been led to expect based on Western democratic polities, it is a reasonable outcome of illiberal democratic governance operating in these two cities.     

Experimental examination of animal trampling effects on artifact movement in dry and water saturated substrates: a test case from South India

This paper presents the motivation, procedures, and results of an experiment that examines short episodes of animal trampling in dry and water saturated substrates in South India. While horizontal artifact displacement was similar to that modeled by other trampling experiments, vertical artifact displacement in water saturated substrates was greater than any reported experiment to date. The toolstone used in this experiment, a silicious limestone, exhibited minimal damage after trampling. Artifact inclination patterning appeared to be a potentially diagnostic middle-range marker of trampling in water saturated substrates. Given the abundant number of Paleolithic sites that are located on flat, open surfaces near water-bodies, or experience monsoonal climatic regimes, we propose that future excavations should measure artifact inclination on a regular basis.