Environment of the Razdorskoye multilayer settlement (Rostov region, southern Russia)

The area of southern Russia between the northern shore of the Black Sea and Caspian Sea includes steppe and desert-steppe belts which form a contact zone between the forests of the Caucasus and Eurasian steppes. The climate is dry and continental. The mean annual temperature is + 5°C, the January temperature varies between -3°C and -7°C and the mean July temperature between +19°C and +23°C. The annual frostfree period is 165–195 days and annual precipitation 400–600 mm. A major part of the area is occupied by arable and pasture land

Pattern of extinction of the woolly mammoth in Beringia.

Extinction of the woolly mammoth in Beringia has long been subject to research and speculation. Here we use a new geo-referenced database of radiocarbon-dated evidence to show that mammoths were abundant in the open-habitat of Marine Isotope Stage 3 (∼45-30 ka). During the Last Glacial Maximum (∼25-20 ka), northern populations declined while those in interior Siberia increased. Northern mammoths increased after the glacial maximum, but declined at and after the Younger Dryas (∼12.9-11.5 ka). Remaining continental mammoths, now concentrated in the north, disappeared in the early Holocene with development of extensive peatlands, wet tundra, birch shrubland and coniferous forest. Long sympatry in Siberia suggests that humans may be best seen as a synergistic cofactor in that extirpation. The extinction of island populations occurred at ∼4 ka. Mammoth extinction was not due to a single cause, but followed a long trajectory in concert with changes in climate, habitat and human presence

Postglacial Development of Kazakhstan Pine Forests

Fossil pollen records from two peatlands and two lakes in Kazakhstan provide radiocarbon-dated evidence of vegetation change since 13 000 BP. During the Lateglacial open spruce (Picea obovata) forests started spreading along river valleys and over the Kazakhstan Foothills. By 9500 BP, the southern limit of spruce approached its present-day position. Between 9500 and 8000 BP steppe and open birch forests formed the vegetation in the south of the West Siberian Lowland. Dry steppe and semi-desert were the main types of vegetation in north Kazakhstan. From 7000 to 5500 BP Scots pine (Pinus sylvestris L.) expanded in Kazakhstan and reached its present day southern limit. Since 5500 BP pine has formed monospecific forests in the lrtysh-Semipalatinsk area and in the northern part of the Kazakhstan Foothills. By 5000 BP lime (Tilia cordata) penetrated into the northern part of the Kazakhstan Foothills. The ranges of oak (Quercus robur), elm (Ulmus glabra) and black alder (AInus glutinosa) also expanded. The period 4500-3600 BP was characterised by a drier and more continental climate. During that time, the forested area decreased. The ranges of broadleaved trees and alder were reduced. A phase of less continental climate occurred 3300-2800/ 2700 BP. By 1500 BP the present southern limit of Scots pine was established.Les données palynologiques de quatre stations au Kazakhstan ont permis de reconstituer l'histoire de la végétation depuis 13 000 BP. Au Tardiglaciaire, des pessières claires à Picea obovata ont commencé à occuper les vallées des fleuves et les collines de Kazakhs. Vers 9500 BP la limite méridionale moderne de Picea obovata fut atteinte. Entre 9500-8000 BP les steppes et forêts claires de bouleaux (Betula alba) étaient répandues au sud de la Sibérie occidentale. Des steppes sèches et des semi-déserts constituaient alors la végétation du nord du Kazakhstan. Entre 7000 et 5500 BP, le pin sylvestre (Pinus sylvestris) s'est répandu au Kazakhstan jusqu'à sa limite méridionale actuelle. Depuis 5500 BP, Ie pin a constitué des forêts monospécifiques dans la région de Semipalatinsk-lrtysh et dans la partie septentrionale des collines de Kazakhs. Vers 5000 BP. Ie tilleul (Tilia cordata) fut présent dans la partie septentrionale des collines de Kazakhs. Les aires du chêne (Quercus robur), de l'orme (Ulmus glabra) et de l'aulne (AInus glutinosa) se sont étendues. Entre 4500 et 3600 BP, le climat est devenu plus sec et plus continental. L'aire de peuplement des forêts a diminué. La répartition des arbres aux larges feuilles et de l'aulne ont diminué. Un climat moins continental s'est instauré entre 3300 et 2800/2700 BP. Vers 1500 BP, la limite méridionale actuelle du pin s'est établie.Fossile Pollen-Belege von zwei Torfmooren und zwei Seen in Kasachstan liefern mittels Kohlenstoffdatierung den Nachweis einer Vegetationverànderung seit 13 000 v.u.Z. Im Spâtglazial begannen offene Fichtenwâlder (Picea obovata) sich entlang der Flusstâler und ùber die Gebirgsauslâufer Kasachstans auszubreiten. Um 9500 v.u.Z. bildeten Steppen und offene Birkenwàlder die Vegetation im Sùden des westsibirischen Tieflands. Trockene Steppen und Halbwùsten waren die hauptsàchlichen Vegetationstypen in Nord-Kasachstan. Von 7000 bis 5500 v.u.Z. breitete sich die Fôhre (Pinus silvestris L) in Kasachstan aus und erreichte ihre heutige sùdliche Grenze. Seit 5500 v.u.Z. hat die Kiefer monospezifische Wàlder im Irtysh-Semipalatinsk-Gebiet und im nôrdlichen Teil der Gebirgsauslâufer Kasachstans gebildet. Um 5000 v.u.Z. drang die Linde (Tilia cordata) in den nôrdlichen Teil der Gebirgsauslâufer Kasachstans ein. Die Ausdehnung von Eiche (Quercus robur), Ulme (Ulmus glabra) und Schwarzerle (AInus glutinosa) nahm auch zu. Die Zeit von 4500 - 3600 v.u.Z. zeichnete sich durch ein trockeneres und mehr kontinentales Klima aus. Wâhrend dieser Zeit nahm die bewaldete Zone ab. Das Vorkommen von grossblâttrigen Bàumen und Erlen nahm ab. Eine Phase weniger kontinentalen Klimas trat zwischen 3300 - 2800/2700 v.u.Z. ein. Um 1500 v.u.Z. war die gegenwârtige sùdliche Grenze der Fôhre etabliert

Quantum Alternating Operator Ansatz (QAOA) beyond low depth with gradually changing unitaries

The Quantum Approximate Optimization Algorithm and its generalization to Quantum Alternating Operator Ansatz (QAOA) is a promising approach for applying quantum computers to challenging problems such as combinatorial optimization and computational chemistry. In this paper, we study the underlying mechanisms governing the behavior of QAOA circuits beyond shallow depth in the practically relevant setting of gradually varying unitaries. We use the discrete adiabatic theorem, which complements and generalizes the insights obtained from the continuous-time adiabatic theorem primarily considered in prior work. Our analysis explains some general properties that are conspicuously depicted in the recently introduced QAOA performance diagrams. For parameter sequences derived from continuous schedules (e.g. linear ramps), these diagrams capture the algorithm's performance over different parameter sizes and circuit depths. Surprisingly, they have been observed to be qualitatively similar across different performance metrics and application domains. Our analysis explains this behavior as well as entails some unexpected results, such as connections between the eigenstates of the cost and mixer QAOA Hamiltonians changing based on parameter size and the possibility of reducing circuit depth without sacrificing performance

The changing water cycle: Burabay National Nature Park, Northern Kazakhstan

Water resources in Central Asia are scarce, so complicated issues arise from this. Kazakhstan is a Central Asian landlocked country which has mostly closed drainage basins, characterized by endorheic lakes that do not drain to the oceans. These endorheic lakes are very sensitive to climate change and anthropogenic influences. Very few studies have been conducted on the hydrological cycle of the small endorheic lakes. This work reviews the endorheic lakes within Burabay National Nature Park (BNNP), Northern Kazakhstan. BNNP is a small ecozone consisting of terminal lakes watersheds covered by mixed forests and grasslands. These endorheic lakes have been drying out during the last one hundred years or so with the water level decrease accelerated in the past few decades. According to historical observations (1935-2014), on the one hand precipitation amounts did not significantly change, while on the other hand, air temperature steadily increased. The lake level decrease is most probably caused by a water budget deficit, with evaporation exceeding the precipitation inputs in the long-term. The direct anthropogenic impact (water abstraction) plays a minor role in deterioration of water levels, with most significant impacts through localized land use changes such as road and building construction in the catchments. The future of the park’s sensitive ecosystems in a changing climate is uncertain; therefore, BNNP requires modern ecohydrological monitoring methods and analysis tools to improve our understanding of its hydrological cycle variability, and to enable us to develop adequate adaptation and mitigation measures

A 12.5-kyr history of vegetation dynamics and mire development with evidence of Younger Dryas larch presence in the Verkhoyansk Mountains, East Siberia, Russia

A 415 cm thick permafrost peat section from the Verkhoyansk Mountains was radiocarbon-dated and studied using palaeobotanical and sedimentological approaches. Accumulation of organic-rich sediment commenced in a former oxbow lake, detached from a Dyanushka River meander during the Younger Dryas stadial, at ∼12.5 kyr BP. Pollen data indicate that larch trees, shrub alder and dwarf birch were abundant in the vegetation at that time. Local presence of larch during the Younger Dryas is documented by well-preserved and radiocarbon-dated needles and cones. The early Holocene pollen assemblages reveal high percentages of Artemisia pollen, suggesting the presence of steppe-like communities around the site, possibly in response to a relatively warm and dry climate ∼11.4–11.2 kyr BP. Both pollen and plant macrofossil data demonstrate that larch woods were common in the river valley. Remains of charcoal and pollen of Epilobium indicate fire events and mark a hiatus ∼11.0–8.7 kyr BP. Changes in peat properties, C31/C27 alkane ratios and radiocarbon dates suggest that two other hiatuses occurred ∼8.2–6.9 and ∼6.7–0.6 kyr BP. Prior to 0.6 kyr BP, a major fire destroyed the mire surface. The upper 60 cm of the studied section is composed of aeolian sands modified in the uppermost part by the modern soil formation. For the first time, local growth of larch during the Younger Dryas has been verified in the western foreland of the Verkhoyansk Mountains (∼170 km south of the Arctic Circle), thus increasing our understanding of the quick reforestation of northern Eurasia by the early Holocene