The propagation of the mesospheric two-day wave in the southern hemisphere

The results of an analysis of mesospheric wind data collected simultaneously at Grahamstown (South Africa) and Adelaide (South Australia) during the summer appearances of the quasi-two-day wave over a period of eight years are presented and discussed. It is concluded that the apparent zonal wave-number k which characterises the westward travelling wave is significantly less than the value of 3 suggested by current theories. Differences in local conditions and/or observing techniques are found to be unlikely causes of the discrepancy. It is shown that these results, as well as certain global features observed by satellite, could arise as a result of the superposition of modes with different k but similar frequencies.     

The effect of rapid changes in ionospheric flow on velocity vectors deduced from radar beam-swinging experiments

The effects on the horizontal ionospheric velocity vectors deduced from radar beam-swinging experiments, which occur when changes in the flow take place on short time scales compared with the experiment cycle time, are analysed in detail. The further complications which arise in the interpretation of beam-swinging data, due to longitudinal gradients in the flow and to field-aligned flows, are also considered. It is concluded that these effects are unlikely to seriously compromise statistical determinations of the response time of the flow, e.g. to changes in the north-south component of the IMF, such as have been recently reported by Etemadi et al. (1988, Planet. Space Sci. 36, 471), using EISCAT ‘Polar’ data.     

Comparisons between EISCAT observations and model calculations of the high latitude ionosphere

Calculations using a numerical model of the convection dominated high latitude ionosphere are compared with observations made by EISCAT as part of the UK-POLAR Special Programme. The data used were for 24–25 October 1984, which was characterized by an unusually steady IMF, with Bz < 0 and By > 0; in the calculations it was assumed that a steady IMF implies steady convection conditions. Using the electric field models of Heppner and Maynard (1983) appropriate to By > 0 and precipitation data taken from Spiroet al. (1982), we calculated the velocities and electron densities appropriate to the EISCAT observations. Many of the general features of the velocity data were reproduced by the model. In particular, the phasing of the change from eastward to westward flow in the vicinity of the Harang discontinuity, flows near the dayside throat and a region of slow flow at higher latitudes near dusk were well reproduced. In the afternoon sector modelled velocity values were significantly less than those observed. Electron density calculations showed good agreement with EISCAT observations near the F-peak, but compared poorly with observations near 211 km. In both cases, the greatest disagreement occurred in the early part of the observations, where the convection pattern was poorly known and showed some evidence of long term temporal change. Possible causes for the disagreement between observations and calculations are discussed and shown to raise interesting and, as yet, unresolved questions concerning the interpretation of the data. For the data set used, the late afternoon dip in electron density observed near the F-peak and interpreted as the signature of the mid-latitude trough is well reproduced by the calculations. Calculations indicate that it does not arise from long residence times of plasma on the nightside, but is the signature of a gap between two major ionization sources, viz. photoionization and particle precipitation.     

Labor resistance and municipal power: Scalar mismatch in the Los Angeles Green New Deal

In 2019, the Mayor of Los Angeles announced the Los Angeles Green New Deal (LAGND), an ambitious plan to shift the city's power system to 100% renewables by 2045. The Los Angeles Department of Water and Power (LADWP)—the electricity provider for the city and the largest municipally-owned utility in the United States—began a consultation process with local stakeholders and energy system modelers to determine possible scenarios to accomplish this goal. While the LAGND was lauded by environmentalists and progressives both within Los Angeles and beyond, it has been heavily opposed by the IBEW 18, the union that represents nearly all employees at LADWP. IBEW 18 has staged protests, created political advocacy organizations, and funded anti-decarbonization political candidates. This paper draws on 20 semi-structured interviews and other secondary materials to understand the union's oppositionand to demonstrate some of the unique challenges that municipal-scale Green New Deal (GND) plans face. We argue that the tensions between the mayor's office and unionized utility workers can be explained, at least in part, by three instances of scalar misalignment—or mismatch—that arise from trying to undertake a GND plan at the city level. These include mismatch between: (1) the scales of political activism and engagement between the mayor and the union, (2) the aims of the GND narrative and the limits imposed by the jurisdiction of the City of Los Angeles, and (3) the current and future geographies of the electric power system and related infrastructure and its path dependencies.     

L’Histoire, la Fable et le Fabuleux Analyse de la notion de fabuleux

Paul Hazard has clearly shown the concomitance ofThe Crisis of the European consciousness in various domains, under diverse aspects and diverse interrogations. This crisis, these new issues which arise concern as well the concept of temporality which was then in vogue. This article seeks to study its emergence through a specific question which concerns the status and the significance to be given fables and myths which we have inherited from Antiquity. Thanks to the studies by abbé Anselme, Fontenelle, Nicolas Fréret, the chevalier de La Barre and Lévesque de Burigny of the notion of the marvelous, as found in fables, we can better grasp the development of an historical concept.     

Global Poverty and Inequality: Change and Continuity in Late Development

This contribution assesses the ‘converging divergence’ thesis that global inequality is falling and national inequality is rising. The article argues that falling global inequality is primarily due to China's development and that national inequality has risen in some developing countries and fallen in others. In light of the dominance of China's development in the global picture, questions arise as to what has changed and what has not changed outside of China. A set of changes and continuities is presented. It is then argued that these changes and continuities provide for the contemporary relevance an older conceptual lens — that of ‘late development’.     

Anthropological theory and engagement: A zero‐sum game? (Respond to this article at http://www.therai.org.uk/at/debate)

Engagement with pressing social and political issues is often presented as a threat to the elaboration of sophisticated anthropological theory that needs to be protected from such concerns in order to flourish. However the history of anthropological theory demonstrates that some of the discipline's most important contributions have tended to arise as a result of its proponents' desire to engage in such debates. Although we cannot reproduce the cultural models of a previous generation of anthropologists, the future elaboration of ground‐breaking anthropological theory depends upon a rediscovery of such engaged work that does not posit engagement versus theoretical development as a zero‐sum game.     

European statistics on cultural participation and their international comparability

This paper will consider a number of issues. Section 1 will introduce the paper, establishing why reliable internationally comparable statistics on cultural participation are needed. Section 2 will address the major and various difficulties that arise in comparing national surveys, both over time and to each other. Section 3 will consider the problems that persist even with cross-national surveys for comparative purposes. Section 5 will conclude the paper with some policy recommendations.     

The geochronological potential of isoleucine epimerisation in cassowary and megapode eggshells from archaeological sites

Our research demonstrates that the extent of isoleucine epimerisation (A/I) in fragments of avian eggshells provides geochronological information in archaeological contexts. In the archaeological sequence of Hay Cave, northern Queensland, Australia, there is an excellent correspondence between the A/I values of Australian brush-turkey (Alectura lathami) eggshells (n = 99) and independent geochronological control (n = 16 radiocarbon ages including 4 on eggshell calcite). The A/I values identify three phases of deposition during the Holocene at Hay Cave. In contrast to the Alectura eggshell A/I values, a poor correspondence was observed between the A/I values of cassowary (Casuarius) eggshells from Toé (n = 35) and Kria caves (n = 23) (Ayamaru Plateau, Papua) and the depths from which the specimens were recovered in these stratified sequences. Given coherent archaeofauna trends and radiocarbon chronologies (n = 8 and 2 eggshell calcite radiocarbon ages at Toé and Kria, respectively) with respect to depth, the variable A/I values are not explicable in terms of mixing. Rather, the variability is most likely due to exposure of the eggshells to the high temperatures of campfires. Despite the variability, eggshells with relatively low A/I values amongst specimens recovered from similar depths (and therefore presumably least influenced by high temperatures) exhibit a gradual increase in A/I with respect to depth, as expected in a stratified deposit. From this observation it is suggested that the identification of heated eggshells will increase confidence in geochronological information provided by A/I. These studies illustrate the complications that arise from campfire-induced acceleration of amino acid racemisation and emphasise that although this phenomenon is common, it is not universally encountered in archaeological contexts.     

The role of the crown in Hung parliaments

The article deals with the role of the Queen's representative when no one party or stable alliance has a majority in the lower house of parliament Two types of questions are likely to arise: one set of problems relates to the choice of government and the role of the ministry in office when an election produces a hung parliament; the second concerns the situations where a head of government who has suffered (or fears) defeat in the lower house requests a dissolution and new elections. The author examines precedents that have occurred since Evatt and Forsey wrote on the subject and proposes some guidelines for the exercise of the governor's reserve powers.     

Modifications in the nighttime low-latitude ionosphere after southward turning of the IMF

Sharp decreases in Φ_oF2 are found to occur frequently in the nighttime low-latitude ionosphere after southward turning of the IMF B_z component, especially under isolated B_z turnings, i.e. when the IMF has been northward for at least 6 h before its turning. These decreases occur simultaneously (within a 1-h time interval) with the B_z turning. The effect is observed both when a substorm or a magnetic storm begins after B_z has turned southward, and when a noticeable substorm does not occur. The effect is more pronounced after midnight and a maximum at 03 LT. Short-term (with scale times of about 1 h) variations of Φ_oF2 and h_mF2 for B_z southward turning are analysed using a large amount of ground-based and topside sounding data. The decreases in Φ_oF2 are shown to occur at first over the magnetic equator and then, during the second hour after the turning, at the crests of the equatorial anomaly. The ionosphere returns to its undisturbed state, on average, in 4–5 h (if other disturbing agents do not arise). These decreases are suggested to be caused by modifications in the electric field in the low-latitude ionosphere associated with B_z southward turning.     

国外古代失蜡铸造工艺研究综述

本文根据国外有关失蜡工艺研究的文献,着重介绍了西方有关古代失蜡铸造的遗物（蜡模和外范）的出土与发现,以及有关失蜡工艺的起源和西方早期失蜡铸造的方法。     

Amplitude statistics of signals reflected from the ionosphere

Statistical analysis methods used to define the amplitude distributions of signals returned from the ionosphere are discussed in this paper. Emphasis is placed on determining accurately the parameter B, which is the ratio of steady to random components present in a signal. Thus B > 1 if the signal is dominated by the steady component, and B < 1 when the random components dominate. This study investigates the characteristics of B for F-region and E-region ionospheric echoes, as well as some types of spread-F, observed at the southern mid-latitude station Beveridge (37.3 S and 144.6 E). The results indicate that amplitude measurements obtained in approximately 100 s are adequate for determining B. The results also illustrate some effects that the E-region can have on F-region echoes.It is found that frequency spreading, the most common type of spreading observed at Beveridge, displays strong specular reflections and some signal variation due to interference at the leading edge of the F-region echo (i.e. B > 2). Within the spread echo B fluctuates between 0 and about 1.5 but is typically less than 1. The autocorrelation function of signal amplitude has a relatively large coherence interval, suggesting that this type of spread-F is due to interference of specular reflections from coherent irregularity structures with horizontal scale sizes of tens of kilometres rather than scattering from small scale irregularities. A second form of spread-F which would generally be classified as frequency spreading on standard ionoerams is actually due to off-vertical reflections from patches ol irregularities which originate south (poleward) of Beveridge. Echoes within this oblique spread-F (OS-F) do not exhibit coherence indicating that the irregularities responsible are of a smaller scale than those producing normal frequency spread. Finally, the phenomenon of spreading occurring on the second hop, but not the first hop trace is studied. It is shown that the form of the second hop echoes can be reproduced using a simple geometric model of ground scatter. The interpretation is supported by the fact that B for spread second hop echoes is less than 1 whereas it is much greater than 1 for the corresponding first hop echoes.     

Presence of the genus Cuon in upper Pleistocene and initial Holocene sites of the Iberian Peninsula: new remains identified in archaeological contexts of the Mediterranean region

The dhole (Cuon alpinus) has been documented on the Iberian Peninsula throughout the Middle and Upper Pleistocene in archaeological and palaeontological contexts. However, this is an uncommon species among the Iberian quaternary faunae as a whole. This paper focuses on the remains of the genus Cuon recovered in three different sites of the Iberian Mediterranean region and their morphological and osteometrical study. By comparing these with fourteen complete skeletons of Canis lupus, as well as with other remains of C. alpinus, we intend to highlight some anatomical and metrical differences between Cuon and Canis that, added to those already published, could be a functional base-line for the identification of this genus. The identification of this species is complex, especially in archaeological contexts, and in some cases the dhole has been identified as Canis or Canidae. Furthermore, this paper explores the chronology of the presence of the dhole in the Iberian Peninsula and the different contexts where these animals have been recovered from.     

Shining a Light on Dark Tourism: German Bunkers in the British Channel Islands

Abstract

Lying at the heart of Tonbridge and Ashworth's 'dissonant heritage' are issues of disinheritance and the subsequent discord that this can cause. Implicit in this is the lesson for heritage professionals to make sure that the heritage they manage is presented in an honest, ethical and inclusive manner that minimises dissonance. But what, precisely, does this mean in practice? What if those who 'own' the heritage are not professionals, but deeply committed and interested amateur volunteer enthusiasts who have made it their life's work over decades to conserve and look after the heritage, but who are not particularly interested in, or actively resistant to, issues that so concern professionals? These are some of the issues which periodically arise in the British Channel Islands over the most visible heritage of Occupation — the German fortifications, or 'bunkers'.     

Density profiles of sporadic E-layers containing two metal ion species

Ionospheric plasma containing two types of metal ions is investigated under the action of the wind shear mechanism or, alternatively, an electric field causing convergent vertical plasma flow. It is shown that the different ion species are separately collected into thin sheets with a height difference ranging from some hundreds of meters to several kilometers. Theoretical density profiles for Mg⁺ and Fe⁺ ions are calculated assuming a screw-like wind structure or a strong auroral electric field. It is found that the two ion layers usually partially merge forming a single E_s-layer. If the height difference of the ion sheets is not too great as compared to their thicknesses, the E_s-profile is single peaked and approximately symmetric. With increasing layer separation the two sheets will gradually be discerned, until finally a double peaked profile is created. It is suggested that some of the observed complexities in E_s-profiles are caused by the presence of more than one monoatomic ion species.     

Cut marks on the Middle Pleistocene elephant carcass of Áridos 2 (Madrid,Spain)

Áridos 1 and Áridos 2 (Madrid, Spain) are two Middle Pleistocene sites belonging to the isotopic stages 9–11. Both places contain partial carcasses of Elephas (Paleoxodon) antiquus associated to Acheulian stone tools. In this work, the taphonomic study of the elephant remains of Áridos 2 is presented. This study has documented several cut marks on different bones, which indicate bulk flesh and viscerae extraction by Middle Pleistocene hominins. Several arguments are provided to support that at least some of the cut marks were made with handaxes, further suggesting that some of these artifacts were butchering tools in this stage of human evolution. Although cut marks on elephant carcasses have been documented at some Middle Pleistocene sites, very few have been published in detail to allow consideration of their status as hominin-imparted marks. By doing so, the present study provides more evidence of large carcass exploitation by hominins during this period.     

Soft X-rays from the sunlit earth's atmosphere

The HEAO-1 A-2 experiment low energy proportional counters have been used to measure the X-ray spectrum of the sunlit earth in the energy range 0.2–0.8 keV. The X-rays arise by coherent scattering of, or fluorescence of atmospheric constituents by, solar coronal X-rays incident on the atmosphere. Although the relative spectral contributions of the two processes depend upon the sun-earth-satellite geometry, fluorescent oxygen and nitrogen K X-ray emission is always important. The observed spectra were compared with calculations in order to derive the coronal temperature and emission measure, parameters that characterize the incident solar spectrum. These derived parameters agree well with the expected values for the nonflaring sun, and good agreement was obtained between measurements closely spaced in time but having a wide range of geometries and counting rates. Thus X-ray observations of the sunlit earth's atmosphere can be a useful monitor of solar activity for satellite-borne instrumentation unable to view the sun directly. The total measured fluorescent line flux agreed well with calculations, but the N : O line ratio did not. This disagreement is attributed to several causes, including the relative weakness of N emission at high altitudes where fluorescence is particularly important, the presence of line emission in the solar spectrum, and possible small calibration errors. Since present detectors cannot resolve the oxygen and nitrogen K X-rays, observation of X-ray fluorescence from the sunlit atmosphere will be useful in monitoring atmospheric constituents only to the extent that total line counting rates depend upon composition. X-rays from the sunlit earth are briefly examined as a source of background in auroral X-ray observations. During nonflare periods this background should be unimportant above about 2 keV.     

Engineering complexity

Abstract

Engineering systems are becoming increasingly complex as they address the challenges of the twenty-first century. However the stability of complex systems has long been difficult to determine, and may indeed represent a technological limit. Some systems are both stable and complex, but in others excessive complexity leads to collapse. Collapse may arise from a tradeoff between optimality and resilience. Recent analysis of very large complex systems shows that behind their apparent lack of order are a number of statistical patterns, which perhaps provide the much sought after pointers to system stability. Components with high levels of connectivity to the rest of a given system, and that can induce coherent behaviour across the system, can produce some spectacular collapses. These may be a special weakness introduced by global communication systems.