Search Results

Most pingos have grown in residual ponds left behind by rapid lake drainage through erosion of ice-wedge polygon systems. The field studies (1969-78) have involved precise levelling of numerous bench marks, extensive drilling, detailed temperature measurements, installation of water pressure transducers below permafrost and water (ice) quality, soil, and many other analyses. Precise surveys have been carried out on 17 pingos for periods ranging from 3 to 9 years. The field results show that permafrost aggradation in saturated lake bottom sediments creates the high pore water pressures necessary for pingo growth. The subpermafrost water pressures frequently approach that of the total litho-static pressure of permafrost surrounding a pingo. The water pressure is often great enough to lift a pingo and intrude a sub-pingo water lens beneath it. The basal diameter of a pingo is established in early youth after which time the pingo tends to grow higher, rather than both higher and wider. The shutoff direction of freezing is from periphery to center. When growing pingos have both through going taliks and also permeable sediments at depth, water may be expelled downwards by pore water expulsion from freezing and consolidation from self loading on saturated sediments. Pingos can rupture from bursting of the sub-pingo water lens. Otherwise, pingo failure is at the top and periphery. Hydraulic fracturing is probably important in some pingo failures. Water loss from sub-pingo water lenses causes subsidence with the subsidence pattern being the mirror image of the growth pattern; i.e. greatest subsidence at the top. Small peripheral bulges may result from subsidence. Old pingos collapse from exposure of the ice core to melting by overburden rupture, by mass wasting, and by permafrost creep of the sides.

AbstractBiome maps spanning the interval from the last glacial maximum to modern times are presented. The biome distributions at 18 ka BP were probably as nearly in equilibrium with climate as are the modern distributions, but deglacial biomes were probably in disequilibrium. Ice sheet configuration was a strong control of climate until 7 ka BP. Regional climate trends can be inferred from changing biome distributions, but during periods of disequilibrium, biome distributions under-represent summer warming. Because of summer cooling by 2-4 °C during the Holocene, largely in the last 3-5 ka, middle and certain early Holocene biome distributions and species compositions are reasonable analogues of future equilibrium displacements due to equivalent warming, at least in areas that were long-since deglaciated. Past biome migration rates in response to rapid regional warming during deglaciation were mainly in the range of 100-200 m per year. If these rates pertain in the future, biomes may shift 10-20 km in most regions over the next century. A major impediment to using former Holocene conditions as a guide to future conditions is that warmer Holocene summers were accompanied by colder winters, whereas warmer future summers will be accompanied by warmer winters.

In the history of exchanges between Islamicate and Sanskrit astral sciences, Nityānanda's Siddhāntasindhu (c. early 1630s), composed at the court of the Mughal emperor Shāh Jahān (r. 1628─58), is among the earliest examples of a Persian astronomical text translated into Sanskrit. In an earlier study, Misra (2021) described the sociohistorical context in which Nityānanda translated Mullā Farīd's Zīj-i Shāh Jahānī (c. 1629/30) into Sanskrit, and among other things, provided parallel comparative editions, with English translations, of the Persian and Sanskrit text describing the computation of true declination of a celestial object. While Misra's paper focused on the linguistic aspects of the translation process, the present paper studies the mathematics of the three methods of computing the true declination vis-à-vis Nityānanda's recension of his Sanskrit translations from his germinal Siddhāntasindhu to his chef d'oeuvre, the Sarvasiddhāntarāja (1638). The paper begins by discussing the transformation of the Sanskrit text from the Siddhāntasindhu Part II.6 to the spaṣṭakrāntyadhikāra 'topic of true declination' in the gaṇitādhyāya 'chapter on computations' (henceforth identified as I.spa·krā) of his Sarvasiddhāntarāja. The metrical verses of Sarvasiddhāntarāja I.spa·krā are edited and translated into English for the very first time. A large part of this paper focuses on the technical (mathematical) analysis of the three methods of true declination, and includes detailed explanatory and historical notes. The paper also includes several technical appendices and an indexed glossary of technical terms.

Keywords: Sanskrit astral sciences, Persian astronomy, true declination computation, Science in Mughal India, gaṇita jyotiṣa, Nityānanda, Mullā Farīd, Sarvasiddhāntarāja, Siddhāntasindhu, Zīj-i Shāh Jahānī, Zīj-i Ulugh Beg

The current publication offers the first English translation of a cluster of medieval and early modern Slavonic renditions of Byzantine Greek editions of ancient medical compositions, the authorship of which is attributed to Galen. Among the emblematic texts deserving special attention are his celebrated commentaries on the Corpus Hippocraticum, the direct Greek Vorlage of which remains unidentified. The Slavonic translations of these Galenic paraphrases refer to various medical conditions as well as human anatomy and physiology; they contain discussions on diagnosis, therapeutics, and health care (including dietetics), as well as astral medicine (e.g., calendrical templates of recommended procedures according to the zodiac, winter and summer solstices, autumn and vernal equinoxes, lunar phases, the position of the Pleiades). While the earliest extant Slavonic manuscript witnesses are dated to the first quarter of the 15th century, their protographs must have originated much earlier among the cloistral scriptoria of Mt Athos and further disseminated through monastic networks within the Byzantine Commonwealth, from the Balkans to Russia. These texts represent a small but important contribution to the reception history of Galenic heritage within the Slavonic world, which has hardly been recognized.

Keywords: Paraphrases of Galenic corpus, knowledge transmission in Old Church Slavonic (Palaeoslavonic), history of medicine and human sciences in the Byzantine Commonwealth, monastic scriptoria as centers for production and dissemination of medical manuscripts, cloisters as infirmaries, monks as medical practitioners, saints as healers