scholarly journals On the spatial segregation of helicity by inertial waves in dynamo simulations and planetary cores

2018 ◽  
Vol 851 ◽  
pp. 268-287 ◽  
Author(s):  
P. A. Davidson ◽  
A. Ranjan
Keyword(s):  
Numerical Simulations ◽  
Strongly Correlated ◽  
Inertial Waves ◽  
The South ◽  
The North ◽  
Planetary Cores ◽  
Local Wave ◽  
Wave Flux ◽  
The Relationship

The distribution of kinetic helicity in a dipolar planetary dynamo is central to the success of that dynamo. Motivated by the helicity distributions observed in numerical simulations of the Earth’s dynamo, we consider the relationship between the kinetic helicity, $h=\boldsymbol{u}\boldsymbol{\cdot }\unicode[STIX]{x1D735}\times \boldsymbol{u}$, and the buoyancy field that acts as a source of helicity, where $\boldsymbol{u}$ is velocity. We show that, in the absence of a magnetic field, helicity evolves in accordance with the equation $\unicode[STIX]{x2202}h/\unicode[STIX]{x2202}t=-\unicode[STIX]{x1D735}\boldsymbol{\cdot }\boldsymbol{F}+S_{h}$, where the flux, $\boldsymbol{F}$, represents the transport of helicity by inertial waves, and the helicity source, $S_{h}$, involves the product of the buoyancy and the velocity fields. In the numerical simulations it is observed that the helicity outside the tangent cylinder is predominantly negative in the north and positive in the south, a feature which the authors had previously attributed to the transport of helicity by waves (Davidson & Ranjan, Geophys. J. Intl, vol. 202, 2015, pp. 1646–1662). It is also observed that there is a strong spatial correlation between the distribution of $h$ and of $S_{h}$, with $S_{h}$ also predominantly negative in the north and positive in the south. This correlation tentatively suggests that it is the in situ generation of helicity by buoyancy that establishes the distribution of $h$ outside the tangent cylinder, rather than the dispersal of helicity by waves, as had been previously argued by the authors. However, although $h$ and $S_{h}$ are strongly correlated, there is no such correlation between $\unicode[STIX]{x2202}h/\unicode[STIX]{x2202}t$ and $S_{h}$, as might be expected if the distribution of $h$ were established by an in situ generation mechanism. We explain these various observations by showing that inertial waves interact with the buoyancy field in such a way as to induce a source $S_{h}$ which has the same sign as the helicity in the local wave flux, and that the sign of $h$ is simply determined by the direction of that flux. We conclude that the observed distributions of $h$ and $S_{h}$ outside the tangent cylinder are consistent with the transport of helicity by waves.

scholarly journals HA NOI – HUE – SAI GON IN TERRITORY EXPANSION TOWARD THE SOUTH AND UNIFICATION OF THE COUNTRY (1069–1802)

2020 ◽  
Vol 129 (6E) ◽  
pp. 33-43
Author(s):  
Nguyễn Quang Ngọc
Keyword(s):  
Eighteenth Century ◽  
Eleventh Century ◽  
Development Trend ◽  
Early History ◽  
Mutual Support ◽  
The South ◽  
The North ◽  
Starting Point ◽  
Imperial Capital ◽  
The Relationship

Vietnam is a country of an early history establishment with three archaeological centres: Dong Son in the North, Sa Huynh in the Central, and Oc Eo in the South. In the long history, these three centres unite and gather into a unified block, step by step, becoming a mainstream development trend. By the eleventh century, Thang Long capital (Hanoi) is a typical representative, the starting point for the course of advancement to the South of the Vietnamese. Later, Phu Xuan (Hue) from the fourteenth century and Gia Dinh (Saigon) from the seventeenth century directly multiply resources, deciding the success of the course of territory expansion and determining the southern territory of the nation Dai Viet – Vietnam in the middle of the eighteenth century. The Tay Son movement at the end of the eighteenth century starts unifying the country, but the course is not completed with numerous limitations. The mission of unifying the whole country is assigned back to Nguyen Anh. Nguyen Anh continually builds Gia Dinh into a firm basement for proceeding to conquer the imperial capital of Hue and the citadel Thang Long, completing the 733-year journey to expand the southern territory (1069–1802) and unifying the whole country into a single unit. Hanoi – Hue – Saigon in the relationship and mutual support has become the three pillars that determine all successes throughout the long history and in each stage of expansion and shaping of territory and unification of the country.

The Earliest Ceramics of the Northern Maya Lowlands

2018 ◽  
Author(s):  
E. Wyllys Andrews V ◽  
George J. Bey ◽  
Christopher M. Gunn
Keyword(s):  
The South ◽  
Maya Lowlands ◽  
The North

This chapter examines the evidence for pre-Mamom pottery in the northern Maya lowlands. This pottery, recognized as the Ek complex, has been identified at Komchen and Kiuic as well as several other sites in the western part of northern Yucatan. The identification, description, and comparison of this pottery with contemporary complexes from the southern Maya lowlands establishes Ek pottery as the oldest ceramic complex (900-800 B.C.) recovered in the north. Northern Maya culture is thought to be the result of a process of in situ evolution which begins at roughly the same time it happened in the south.

scholarly journals Position and structure of the Subtropical/Azores Front region from combined Lagrangian and remote sensing (IR/altimeter/SeaWiFS) measurements

1999 ◽  
Vol 79 (5) ◽  
pp. 769-792 ◽  
Author(s):  
Robin D. Pingree ◽  
Carlos Garcia-Soto ◽  
Bablu Sinha
Keyword(s):  
Remote Sensing ◽  
Far East ◽  
The South ◽  
Subtropical Front ◽  
The North ◽  
Mid Atlantic Ridge ◽  
Temperature Contrast ◽  
Front Region ◽  
Lagrangian Flow

The position and structure of the North Atlantic Subtropical Front is studied using Lagrangian flow tracks and remote sensing (AVHRR imagery: TOPEX/POSEIDON altimetry: SeaWiFS) in a broad region (∼31° to ∼36°N) of marked gradient of dynamic height (Azores Current) that extends from the Mid-Atlantic Ridge (MAR), near ∼40°W, to the Eastern Boundary (∼10°W). Drogued Argos buoy and ALACE tracks are superposed on infrared satellite images in the Subtropical Front region. Cold (cyclonic) structures, called ‘Storms’, and warm (anticyclonic) structures of 100–300 km in size can be found on the south side of the Subtropical Front outcrop, which has a temperature contrast of about 1°C that can be followed for ∼2500 km near 35°N. Warmer water adjacent to the outcrop is flowing eastward (Azores Current) but some warm water is returned westward about 300 km to the south (southern Counterflow). Estimates of horizontal diffusion in a Storm (D=2.2×102 m2 s−1) and in the Subtropical Front region near 200 m depth (Dx=1.3×104 m2 s−1, Dy=2.6×103 m2 s−1) are made from the Lagrangian tracks. Altimeter and in situ measurements show that Storms track westwards. Storms are separated by about 510 km and move westward at 2.7 km d−1. Remote sensing reveals that some initial structures start evolving as far east as 23°W but are more organized near 29°W and therefore Storms are about 1 year old when they reach the MAR (having travelled a distance of 1000 km). Structure and seasonality in SeaWiFS data in the region is examined.

scholarly journals The stratigraphy of the Neogene-Quaternary succession in the southwest Netherlands from the Schelphoek borehole (42G4-11/42G0022) – a sequence-stratigraphic approach

2007 ◽  
Vol 86 (4) ◽  
pp. 317-332 ◽  
Author(s):  
A.A. Slupik ◽  
F.P. Wesselingh ◽  
A.C. Janse ◽  
J.W.F. Reumer
Keyword(s):  
The Netherlands ◽  
Coastal Area ◽  
Late Quaternary ◽  
Tidal Channel ◽  
The South ◽  
Glacial Cycles ◽  
Sequence Stratigraphic ◽  
The North ◽  
Mammal Fauna

AbstractWe investigate the stratigraphy of Neogene and Quaternary intervals of the Schelphoek borehole (Schouwen, Zeeland, the Netherlands). The Breda Formation (Miocene-Zanclean) contains three sequences separated by hiatuses. The Oosterhout Formation (Zanclean-Piacenzian) contains at least two sequences. This formation is overlain by seven sequences of the Gelasian Maassluis Formation that almost certainly represent glacial cycles. The three lowermost sequences are provisionally assigned to the Praetiglian (MIS 96, MIS 98 and MIS 100). A large hiatus exists between the top of the Maassluis Formation and the base of the late Middle to Late Quaternary succession. Due to extensivein situreworking of older strata (including fossils) at the base of several of the formations, their exact boundaries are difficult to establish. The Neogene succession in the Schelphoek borehole is compared to the stratigraphic successions in the Antwerp area to the south and the Dutch coastal area and continental platform to the north. Finally, the stratigraphic context of the Gelasian (‘Tiglian’) mammal fauna dredged from the bottom of a major tidal channel in the adjacent Oosterschelde is assessed by comparison with the Schelphoek borehole.

The Interaction Between Strength and Fatigue Reliability for a Minimum Structure in Shallow Water

2003 ◽  
Vol 125 (4) ◽  
pp. 281-287 ◽  
Author(s):  
G. K. Cole ◽  
B. F. Ronalds ◽  
E. Fakas
Keyword(s):  
Shallow Water ◽  
Wave Climate ◽  
Offshore Structures ◽  
Life Extension ◽  
Fatigue Reliability ◽  
North West ◽  
The North ◽  
Local Wave ◽  
Structural Inspection ◽  
The Relationship

The relationship between strength and fatigue reliability of an offshore platform is an important aspect in the setting of appropriate structural inspection programs, as well as providing valuable information when considering the life extension of ageing offshore structures. This paper uses the example of a braced monopod to examine the interaction between strength and fatigue reliability for shallow-water platforms subjected to wave climates typical of the North West Shelf of Australia. The central role played by the local wave climate in both the strength and fatigue response of the structure is investigated. The probability of fatigue failure at the critical location was found to be approximately three orders of magnitude less than the overall probability of storm overload failure. This inequity between strength and fatigue reliability raises the possibility of redirecting inspection effort toward higher-risk threats such as accidental damage and corrosion. The potential for further optimizing the total life-cycle costs of new offshore structures is also briefly discussed.

The waterbodies of the Dallol volcano: A physico-chemical and geo-microbial survey

2020 ◽  
Author(s):  
Hugo Moors ◽  
Miroslav Honty ◽  
Carla Smolders ◽  
Ann Provoost ◽  
Mieke De Craen ◽  
...  
Keyword(s):  
Saline Water ◽  
Halophilic Archaea ◽  
Mining Area ◽  
Ex Situ ◽  
Base Region ◽  
The South ◽  
North East ◽  
The North ◽  
Physico Chemical

<p>The geological extreme Dallol region, located around the Dallol volcano in the north-east of Danakil depression (Ethiopia), is considered as one of the harshest and hottest places on Earth. The geology is made up of years and years of evaporates accumulation. Volcanic activity generates ascending brines that may cross and mix with aquifers from inflowing meteoric water originating from the Ethiopian highlands on the east of the Danakil depression. When these mixtures reach the surface they can generate hydrothermal springs giving rise to waterbodies in the form of small ponds or lakes. During the Europlanet 2018 Danakil field expedition, ten of these saline waterbodies were extensively studied by <em>in situ</em> measurements and <em>ex situ</em> geo–physico-chemical and –microbiological analyses of collected samples, liquids as well as sediments.</p><p>The <em>in situ</em> physico-chemical measurements clearly indicated the extreme nature of all ten investigated lakes. Laboratory analyses of the collected batch samples of liquids and sediments confirmed the extreme character of the waterbodies and complements our geological survey of the region with valuable geo–chemical and –microbiological data.</p><p>Based on our analytical results, the relative small Dallol region can still be subdivided into three geological smaller areas: the outcrop zone, the volcanic base region and the distant south area. The outcrop zone is dominated by sodium, iron and potassium. Oxidation processes in the outflowing superheated ferrous and sulfidic rich brine give rise to some of the most acidic ponds on our planet. In the ponds and lakes of the volcanic base region, incredible high amounts of calcium and/or magnesium can remain in their dissolved form as the most dominant and quasi only available anion is chloride. This region is host for the most saline water body on Earth. Chemical analysis of the lakes of the distant south area show that sodium is by far the most dominant cation. It is therefore no surprise that the large Karum Lake in the south region is economically exploited for the mining of sodium chloride.</p><p>Our mineralogy analyses render results that are completely in line with the observed geochemistry of the waterbodies. Halite and sylvite are the most present minerals in the Dallol outcrop zone associated with some gypsum and in one case with anhydrite. The geology around the waterbodies of volcanic base zone are a little bit more divers. On the shores of the Gaet’ale Pond tachyhydrite, chloromagnesite, halite and sylvite is determined, while the Black Lake is surrounded by bischofite and carnalite. Logically, the mineralogy of the south area, the salt mining area, is dominated by halite and sylvite.</p><p>Apparently, the geochemistry of the outcrop zone and volcanic base region is so harsh that no extremophilic organism is able to survive in these areas. Only in the distant south area did we find indications of the presence of halophiles. Besides the bacterial genus <em>Salinibacter</em>, our 16S rDNA microbiological fingerprinting indicates the presence of halophilic archaea like:  <em>Halobaculum sp., Halobellus sp., Halomicroarcula sp., Halorientalis sp.</em> with the majority of the population being <em>Candidatus Nanosalina sp</em>.</p>

scholarly journals From meteorological to hydrological drought using standardised indicators

2016 ◽  
Vol 20 (6) ◽  
pp. 2483-2505 ◽  
Author(s):  
Lucy J. Barker ◽  
Jamie Hannaford ◽  
Andrew Chiverton ◽  
Cecilia Svensson
Keyword(s):  
Time Series ◽  
Hydrological Drought ◽  
Annual Rainfall ◽  
Strongly Correlated ◽  
Propagation Characteristics ◽  
The South ◽  
Drought Characteristics ◽  
The North ◽  
The Uk ◽  
Hydrological Droughts

Abstract. Drought monitoring and early warning (M & EW) systems are a crucial component of drought preparedness. M & EW systems typically make use of drought indicators such as the Standardised Precipitation Index (SPI), but such indicators are not widely used in the UK. More generally, such tools have not been well developed for hydrological (i.e. streamflow) drought. To fill these research gaps, this paper characterises meteorological and hydrological droughts, and the propagation from one to the other, using the SPI and the related Standardised Streamflow Index (SSI), with the objective of improving understanding of the drought hazard in the UK. SPI and SSI time series were calculated for 121 near-natural catchments in the UK for accumulation periods of 1–24 months. From these time series, drought events were identified and for each event, the duration and severity were calculated. The relationship between meteorological and hydrological drought was examined by cross-correlating the 1-month SSI with various SPI accumulation periods. Finally, the influence of climate and catchment properties on the hydrological drought characteristics and propagation was investigated. Results showed that at short accumulation periods meteorological drought characteristics showed little spatial variability, whilst hydrological drought characteristics showed fewer but longer and more severe droughts in the south and east than in the north and west of the UK. Propagation characteristics showed a similar spatial pattern with catchments underlain by productive aquifers, mostly in the south and east, having longer SPI accumulation periods strongly correlated with the 1-month SSI. For catchments in the north and west of the UK, which typically have little catchment storage, standard-period average annual rainfall was strongly correlated with hydrological drought and propagation characteristics. However, in the south and east, catchment properties describing storage (such as base flow index, the percentage of highly productive fractured rock and typical soil wetness) were more influential on hydrological drought characteristics. This knowledge forms a basis for more informed application of standardised indicators in the UK in the future, which could aid in the development of improved M & EW systems. Given the lack of studies applying standardised indicators to hydrological droughts, and the diversity of catchment types encompassed here, the findings could prove valuable for enhancing the hydrological aspects of drought M & EW systems in both the UK and elsewhere.

scholarly journals Wage Equalization and Regional Misallocation: Evidence from Italian and German Provinces

2021 ◽  
Author(s):  
Tito Boeri ◽  
Andrea Ichino ◽  
Enrico Moretti ◽  
Johanna Posch
Keyword(s):  
Wage Bargaining ◽  
Spatial Equilibrium ◽  
The South ◽  
Geographical Differences ◽  
Wage Differences ◽  
High Productivity ◽  
Flexible System ◽  
The North ◽  
Employment Rates ◽  
The Relationship

Abstract Italy and Germany have similar geographical differences in firm productivity – with the North more productive than the South in Italy and the West more productive than the East in Germany – but have adopted different models of wage bargaining. Italy sets wages based on nationwide contracts that allow for limited local wage adjustments, while Germany has moved toward a more flexible system that allows for local bargaining. We find that Italy exhibits limited geographical wage differences in nominal terms and almost no relationship between local productivity and local nominal wages, while Germany has larger geographic wage differences and a tighter link between local wages and local productivity. As a consequence, in Italy, low productivity provinces have higher non-employment rates than high productivity provinces, because employers cannot lower wages, while in Germany the relationship between non-employment and productivity is significantly weaker. We conclude that the Italian system has significant costs in terms of forgone aggregate earnings and employment because it generates a spatial equilibrium where workers queue for jobs in the South and remain unemployed while waiting. If Italy adopted the German system, aggregate employment and earnings would increase by 11.04% and 7.45%, respectively. Our findings are relevant for other European countries.

Buddhism in the history of China in Southern and Northern kingdoms

2020 ◽  
Vol 2020 (10-4) ◽  
pp. 216-225
Author(s):  
Leonid Yangutov ◽  
Marina Orbodoeva
Keyword(s):  
The State ◽  
The South ◽  
The North ◽  
State Apparatus ◽  
History Of ◽  
Eastern Jin ◽  
Relationship Of ◽  
The Relationship ◽  
Further Development ◽  
North And South

The article is devoted to the history of Buddhism in China during the period of the Southern and Northern Kingdoms (Nanbeichao, 386-589). The features of the development of Buddhism in the North and South are shown. Three aspects were identified: 1) the attitude of emperors of kingdoms to Buddhism; 2) the relationship of the state apparatus and the Buddhist sangha; 3) the process of further development of Buddhism in China in the context of its adaptation to the Chinese mentality, formed on the basis of the traditional worldview. It was revealed that Buddhism in the context of its adaptation to the Chinese mentality, both in the North and in the South, developed with the traditions of Buddhism of the Eastern Jin period to the same extent.

MORPHODYNAMICS OF THE SHORES OF THE VISTULA SPIT (THE BALTIC SEA) IN A PERIOD OF 2002-2015 BY RESULTS OF IN-SITU MEASUREMENTS

2017 ◽  
Author(s):  
Valentina Bobykina ◽  
Valentina Bobykina ◽  
Boris Chubarenko ◽  
Boris Chubarenko ◽  
Konstantin Karmanov ◽  
...  
Keyword(s):  
Erosion Rate ◽  
The South ◽  
The Baltic Sea ◽  
The North ◽  
Quantitative Characteristics ◽  
The Subject ◽  
The Baltic ◽  
First Time

For the first time, the quantitative characteristics of the Vistula Spit shore dynamics based on the ground-based monitoring data for 2002-2015 were presented. On the sea shore, 3 sections can be distinguished by the direction of coastal processes, i.e. the stable section to the north of the Strait of Baltiysk, the eroded 4-km section to the south of the Strait of Baltiysk, with maximum erosion rate up to 2 m/year; in the remaining area of the Spit (21 km) to the Polish border there is an alternation of stable, eroded and accumulative areas. Since 2011, a steady erosion (in the stable segments of the third section) and general weakening of the erosion rate (in the second section) have been recorded. 50% of the length of the lagoon shore was the subject to annual active erosion (0.2 - 1.4 m/year). The beaches of the sea and lagoon shores of the Vistula Spit were mainly composed of medium sands. The alongshore variability in particle size distribution on the sea and lagoon shores (according to the 2015 survey data) actually fail to correlate with long-term dynamic processes, with the exception of the steadily eroded 4-kilometer area on the sea coast to the south of the Strait of Baltiysk. Variations in the composition of sediment along the shore on the shoreline are most likely associated with the results of the latest wave processing (or storm processing and eolian transport in the case of an average beach sample).

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