History of EISCAT – Part 5: Operation and development of the system during the first two decades

This paper gives an inside view of the first 20 years of operation of the Kiruna-Sodankylä-Tromsø (KST) part of EISCAT as experienced and remembered by myself. The paper is subdivided into an Introduction and 13 sections. Sections 1 to 6 describe the organization, staffing and responsibilites of the Sites, with particular emphasis on the transmitter-related work at Tromsø and the commuting of staff and equipment between the Sites. The Headquarters operation is treated in Section 7. The UHF radar system is treated in Section 8. Section 9 is a review of the VHF system, including a summary of transmitter and antenna problems not available elsewhere in easily accessed media. Section 10 treats the computer system and the proprietary control languages EROS, TARLAN and CORLAN. Section 11 describes the signal processing hardware, with special emphasis on the Alker correlator, its idiosyncrasies and the gradual unlocking of its capabilities through UNIPROG, the GEN-system and the G2-system, culminating in the ability to run alternating codes experiments routinely. Section 12 presents the time- and frequency keeping, a non-trivial task in the early 1980s. Finally, Section 13 discusses the UHF spectrum problem and relates how the UHF system had to be constantly upgraded in order to be able to co-exist with the emerging cellphone networks until the final closure of UHF reception at Kiruna and Sodankylä in 2012. The paper ends with some personal reflections.

THE FATE OF THE INKERMAN MONASTERY IN THE 1920S IN THE ARCHIVAL SOURCES

The article considers the reflection in the documents of the State Institution “Archive of the city of Sevastopol" of the history of the Inkerman Monastery (now St. Klimentovsky Monastery) in the 1920s. It is established that this period in its history was one of the most difficult. By the end of the 1920s. The Inkerman Monastery was liquidated in connection with the course of the atheist state. The process of its liquidation can be described as “creeping liquidation". The brethren of the monastery went from a partial permission to continue their ministry to the final closure of the churches. Most of the buildings of the monastery after its abolition were adapted for the needs of the community of the village of Inkerman. The analysis of the documents showed that they are fragmentary, at the same time; they make it possible to understand the processes that took place with the cultural structures of the Sevastopol region in the 1920s. They contain information about churches.

Staging temporary spaces

This chapter analyses the performative urban experiences produced by temporary projects and their claim to publicness and openness to local communities. Through a critical discussion of the promises of ‘vibrancy’ and community engagement, it examines the importance of staging in temporary urban spaces, its co-optation and its everyday, contested performative encounters. The chapter draws extensively on participant observations of temporary projects in the Elephant and Castle shopping centre during the last decade before its final closure. The frictions between staged and unexpected urban encounters challenge the celebration of ‘use value’ as inherently beyond commodification. It reveals the need to attend carefully to local power entanglements and to the potential role of temporary uses in solidarity movements against demolition and displacement.

A Tarim-North India connection in northern Gondwana: Constraints from provenance of early Paleozoic sedimentary rocks in the Altyn Tagh orogen, southeastern Tarim

<p>Amalgamation of northern Gondwana involves a wealth of present-day East Asian blocks (e.g., South China, North China, Alxa, Tarim, Indochina, Qiangtang, Sibumasu, Lhasa, etc.) due to consumption and closure of the Proto-Tethys Ocean. Locating the Tarim craton during assembly of northern Gondwana remains enigmatic, with different models separating Tarim from Gondwana by a paleoceanic domain throughout the Paleozoic, advocating a long-term Tarim-Australia linkage in the Neoproterozoic to the early Paleozoic, or suggesting a Tarim-Arabia connection in the early Paleozoic.</p><p>This study carried out field-based zircon U-Pb dating and Hf isotopic analyses for early Paleozoic sedimentary rocks in the Altyn Tagh orogen, southeastern Tarim. New dating results revealed that the early Paleozoic sedimentary rocks were deposited from ca. 494 to 449 Ma. Provenance tracing indicates the ca. 494-477 Ma sedimentary rocks were primarily sourced from the local Altyn Tagh orogen to the south of the North Altyn Ocean (one branch of the Proto-Tethys Ocean between southeastern Tarim and northern Gondwana). In contrast, the ca. 465-449 Ma sedimentary rocks have remarkably increasing ca. 840-780 Ma, 2.0-1.7 Ga, and 2.7-2.4 Ga detrital zircons, indicating an augmented supply of detritus from the Tarim craton to the north of the North Altyn Ocean. Such a significant provenance shift between ca. 477 and 465 Ma marks the timing of the final closure of the North Altyn Ocean. Combined with the timing of the final closure of other branches of the Proto-Tethys Ocean, the entire Proto-Tethys Ocean might have been progressively closed at ca. 500-420 Ma, resulting in the connection of most East Asian blocks with northern Gondwana. Based on detrital zircon U-Pb-Hf isotopic comparison, Tarim most likely shared a North Indian affinity with many East Asian blocks (such as North Qilian, North Qinling, South China, Indochina, South Qiangtang, etc.). This new finding argues against an Australian or Arabian affinity for the Tarim craton.</p><p>This work was financially supported by National Natural Science Foundation of China Projects (grants 41730213, 42072264, 41902229, 41972237, and 41888101), Hong Kong Research Grants Council General Research Fund (grant 17307918), and Grant-in-Aids for Scientific Research from Japan Society for the Promotion of Science (JSPS) to Prof. Toshiaki Tsunogae (No. 18H01300) and to Dr. Qian Liu (No. 19F19020). JSPS fellowship is also much appreciated.</p>

The Late Triassic Molasse Deposits in Central Jilin Province, NE China: Constraints on the Paleo-Asian Ocean Closure

This paper presents a new detailed study including zircon U-Pb-Hf isotopic, whole-rock geochemical and Sr-Nd isotopic analyses of conglomerate and granitic pebbles from the molasse deposits in central Jilin Province, NE China. These data are used to better constrain the Late Permian–Triassic tectonic evolution regarding particularly the final closure of the Paleo-Asian Ocean (PAO) along the Changhun-Yanji suture (CYS). Zircon U-Pb data indicate that the granitic pebbles formed in the end-Permian (254–253 Ma). The youngest detrital zircon age of 231 Ma from the conglomerate, and presence of the overlying Upper Triassic Sihetun Formation suggests that the molasse deposits on the Jin′gui Island formed during the Late Triassic. The end-Permian granitic rocks display high SiO2 (66.07–74.77 wt %), with low MgO (0.55–2.05 wt %) and Mg# (31.61–43.64) values, together with depleted Hf and Nd isotopic values (εHf(t) = +1.61 to +11.62; εNd(t) = +3.3 to +4.2; (87Sr/86Sr)i = 0.706458–0.706842) and juvenile second-stage Hf model ages (1148–512 Ma), suggesting that they were probably generated by the partial melting of a Meso-Neoproterozoic juvenile metabasaltic lower crust. They are characterized by enrichments in large ion lithophile elements (LILEs) and depletions in high field strength elements (HFSEs), with affinities to igneous rocks forming in a subduction-related setting. This, combined with regional coeval subduction-related magmatic rocks, indicates that the PAO still existed along the CYS. In addition, the identification of Late Triassic molasse deposits on the Jin′gui Island in this study, coupled with occurrences of many Early Triassic syn-collisional granitoids along the CYS, indicates that the final closure of the PAO took place prior to the Late Triassic.

Alveolar Bone Grafting

Alveolar Bone Grafting is a clinical procedure which is performed to maintain the integrity of the alveolar arch in cleft patients. This clinical procedure helps in facilitating eruption of canine and lateral incisors. This chapter discusses the normal anatomy of alveolus, significance of cleft alveolus, surgical steps to ensure separation of a well-defined oral and nasal layer, donor sites for bone grafting, harvesting techniques and final closure of the alveolar cleft. In addition, this chapter further highlights the recent developments in the field of bone regeneration.