Combining Robustness with Efficiency in?the?Estimation of the Variogram

In the present paper, we propose a new method for the estimation of the variogram, which combines robustness with efficiency under intrinsic stationary geostatistical processes. The method starts by using a robust estimator to obtain discrete estimates of the variogram and control atypical observations that may exist. When the number of points used in the fit of a model is the same as the number of parameters, ordinary least squares and generalized least squares are asymptotically equivalent. Therefore, the next step is to fit the variogram by ordinary least squares, using just a few discrete estimates. The procedure is then repeated several times with different subsets of points and this produces a sequence of variogram estimates. The final estimate is the median of the multiple estimates of the variogram parameters. The suggested estimator will be called multiple variograms estimator. This procedure assures a global robust estimator, which is more efficient than other robust proposals. Under the assumed dependence structure, we prove that the multiple variograms estimator is consistent and asymptotically normally distributed. A simulation study confirms that the new method has several advantages when compared with other current methods.     

Processes on the Thermodynamic?Properties?of?Lithium?Borates

正1 Introduction Lithium and its compounds as national strategic resources are extensively used in national defense,industrial and agricultural production.As we know,the salt lakes in the western of China are famous for its high     

Crisis? What crisis? Displacing the spatial imaginary of the fiscal state

This paper argues that there is an immanent and evolving relationship between the prevailing form of taxation and the economic geographies of the state. Despite this, the geographic significance of taxation has been obscured by the language in which its historic transformation tends to be couched. Prevailing fiscal systems tend to be presented as essentially static – institutionally and spatially fixed and routinely inscribed within the fixed boundaries and territories of the ‘sovereign’ fiscal state. Any threat to, or change in the nature or geography of the fiscal state tends to be couched in terms of ‘crisis’ – of negative and discontinuous change. This paper contends that these related and essentially conservative discourses of fiscal geography mask the degree to which fiscal spaces are both multiple and continuously evolving. More importantly, it argues, this fluidity and multiplicity does not threaten the stability and viability of state form, but it is an essential process in its maintenance and reproduction. Running counter to the prevailing discourse of the ‘national economy’, the practice of fiscal geography is an under-analysed but key aspect of the historical evolution and transformation of the imagined geographies of economies.     

Secondary aspects of the harnessing of the Rh?ne (not considering the question of energy)

Since a 1921 law the harnessing of the Rhône River from Lyon to the Mediterranean has been directed by a national company composed of the public sector (fromthe valley) as well as of various consumers or distributors of current such as the SNCF or the EDF. This company, the National Company of the Rhône (CNR), was a precursor to the establishment of the TVA in the United States, although it did not begin operations until aftetr the TVA due to prolonged technical negotiations and to the difficulties involved in locating financial support in a period of economic crisis. Even though the utilization of hydraulic power constitutes the prime aim of the CNR, it has also focused on navigation, irration and other agricultural uses from the outset.This article will not further discuss the hydro-electric stations on the Rhône which usually supply more than 22% of French hydro-electric output from thirteen stations now in operation (total power is 2,350 MW and annual average output is 13,000 GWh). This paper will treat the question of the nature and importance of the side effects of the harnessing of the Rhône apart from its essential energy function.     

Stratigraphy of the Triassic?Jurassic Boundary Successions of the Southern Margin of the Junggar Basin, Northwestern China

The Triassic?Jurassic (Tr?J) boundary marks a major extinction event, which (~200 Ma) resulted in global extinctions of fauna and flora both in the marine and terrestrial realms. There prevail great challenges in determining the exact location of the terrestrial Tr?J boundary, because of endemism of taxa and the scarcity of fossils in terrestrial settings leading to difficulties in linking marine and terrestrial sedimentary successions. Investigation based on palynology and bivalves has been carried out over a 1113 m thick section, which is subdivided into 132 beds, along the Haojiagou valley on the southern margin of the Junggar Basin of the northern Xinjiang, northwestern China. The terrestrial Lower Jurassic is conformably resting on the Upper Triassic strata. The Upper Triassic covers the Huangshanjie Formation overlaid by the Haojiagou Formation, while the Lower Jurassic comprises the Badaowan Formation followed by the Sangonghe Formation. Fifty six pollen and spore taxa and one algal taxon were identified from the sediments. Based on the key-species and abundance of spores and pollen, three zones were erected: the Late Triassic (Rhaetian) Aratrisporites?Alisporites Assemblage, the Early Jurassic (Hettangian) Perinopollenites?Pinuspollenites Assemblage, and the Sinemurian Perinopollenites?Cycadopites Assemblage. The Tr?J boundary is placed between bed 44 and 45 coincident with the boundary between the Haojiagou and Badaowan formations. Beds with Ferganoconcha (?), Unio?Ferganoconcha and Waagenoperna?Yananoconcha bivalve assemblages are recognized. The Ferganoconcha (?) bed is limited to the upper Haojiagou Formation, Unio?Ferganoconcha and Waagenoperna?Yananoconcha assemblages are present in the middle and upper members of the Badaowan Formation. The sedimentary succession is interpreted as terrestrial with two mainly lake deposit intervals within Haojiagou and Badaowan formations, yielding fresh water algae and bivalves. However, the presence of brackish water algae Tasmanites and the marine?littoral facies bivalve Waagenoperna from the Badaowan Formation indicate that the Junggar Basin was influenced by sea water caused by transgressions from the northern Tethys, during the Sinemurian.     

Can the visualization of rip currents prevent drowning accidents? Consideration of the effect of optimism bias

Drowning accidents at beach in Japan are caused by rip currents. To reduce these accidents, a new technology that can detect rip currents and notify beachgoers by using the Internet of Things (IoT) and Artificial Intelligence (AI) was proposed. However, studies on the effect of visualizing rip currents or considering the effect of optimism bias have not been conducted. This study investigates if visualization of rip currents might help in preventing drowning accidents, while considering the effect of optimism bias. The participants were 90 Japanese beachgoers. They were asked to answer questions based on their knowledge of the beach and rip currents, their optimism bias regarding rip currents, and awareness with or without visualization. The results of the analyses suggest that despite optimism bias, the visualization of rip currents increases the tendency of beachgoers to perceive and avoid rip currents. As described above, it was found that by visualizing the rip current, beachgoers were able to perceive and avoid rip currents. In addition, an understanding of rip currents is positively related to the intent to avoid rip currents even when rip currents are visualized. Therefore, it is necessary not only to enhance the avoidance tendency by visualizing rip currents, but also to further enhance knowledge of beachgoers to deepen the understanding of rip currents including the danger associated and methods to avoid them.

     

Empowering the empowered? Slum tourism and the depoliticization of poverty

Mumbai’s Dharavi slum occupies a plot half the size of Central Park. It is home to one million people, with almost half of residents living in spaces under 10 m², making it over six times as dense as daytime Manhattan. Using ethnographic fieldwork and online analysis, this article examines slum tourism and the perceptions and experiences of western visitors. Local tour operators emphasize the productivity of the slum, with its annual turnover of $665 million generated from its hutment industries. Its poor sanitation, lack of clean water, squalid conditions and overcrowding are ignored and replaced by a vision of resourcefulness, hard work and diligence. This presentation of the slum as a hive of industry is so successful that visitors overlook, or even deny, its obvious poverty. Dharavi is instead perceived as a manufacturing hub and retail experience; and in some cases even romanticized as a model of contentment and neighbourliness, with western visitors transformed by ‘life-changing’, ‘eye-opening’ and ‘mind-blowing’ experiences. This article concludes that the potential of slum tours as a form of international development is limited, as they enable wealthy middle-class westerners to feel ‘inspired’, ‘uplifted’ and ‘enriched’, but with little understanding of the need for change.     

Why did life develop on the surface of the Earth in the Cambrian?

Life was limited for most of Earth's history, remaining at a primitive stage and mostly marine until about 0.55 Ga. In the Paleozoic, life eventually exploded and colonized the continental realm. Why had there been such a long period of delayed evolution of life? Early life was dominated by Archaea and Bacteria,which can survive ionizing radiation better than other organisms. The magnetic field preserves the atmosphere, which is the main shield of UV radiation. We explore the hypothesis that the Cambrian explosion of life could have been enabled by the increase of the magnetic field dipole intensity due to the solidification of the inner core, caused by the cooling of the Earth, and the concomitant decrease with time of the high-energy solar flux since the birth of the solar system. Therefore, the two phenomena could be responsible for the growth and thickening of the atmosphere and the development of land surface life.     

Is the tilt of the Thames valley towards the east caused by a distal lobe of the Icelandic mantle plume?

Over the last 30 years, a growing body of research has shown that first-order control of the elevation of Earth's surface is exercised by thermal anomalies in the upper asthenosphere. One line of research is to test models and observations of mantle behaviour against the sedimentary record. A second line of research is to use the sedimentary record to further understanding of mantle behaviour. Here this second line of research is adopted: a particular hypothesis of mantle behaviour is tested against the Quaternary sedimentary record of the Thames valley, England. Schoonman et al. (2017) have proposed that a warm finger of mantle material extending from the Icelandic plume underlies southern England at the present day. That warm finger would represent the distal end of the influence of the Icelandic plume in this area, and would have advanced broadly from west to east, causing a progressive tilt of the surface of the Thames valley towards the east. The warm-finger hypothesis is supported by the evidence reviewed here. That evidence consists of two main sets of observations, both sets established beyond reasonable doubt by many researchers over many years. First, there is the progressive increase in elevation westward from the present-day coast of the North Sea of the 2.5–2 Ma shallow-marine Red and Norwich Crags. Second, there is the subsequent Quaternary record of progressive eastward tilting of the Thames valley shown in the river terraces.     

From post-politics to a politics of possibility? Unravelling the privatization of the Berlin Water Company

This article explores the constraints and contingencies of contemporary urban governance, with reference to the partial privatization (1999) and partial remunicipalization (2012) of the Berlin Water Company (BWB). It outlines the processes through which this major shift in Berlin politics occurred, showing how the mainstream consensus on privatization was disrupted and alternatives to apparent neoliberal conformity emerged. Dynamics apparent in the BWB case – commercialization, privatization, re-regulation, public contestation and remunicipalization – are indicative of the challenges and opportunities of making policy in and beyond the global norms of neoliberalism. It is argued that this case is important because it reveals something about what we might call the “politics of possibility” within the paradigm of neoliberal urban governance: the continuing potential for change within the constraints of an urban governance configured to the logics and needs of markets. Given this, the paper concludes that local contingencies in urban governance problematize sweeping notions of a post-political condition. However observable post-political strategies and outcomes in Berlin and elsewhere are, researchers should not assume that they are inevitably dominant or universal.     

How has coastal erosion affected the prehistoric settlement pattern of the boothbay region of maine?

Erosion of complex, rocky coasts has largely been neglected by geologists. Thus, a geo-archaeological study of coastal erosion was required before analysis of the prehistoric settlement pattern could be undertaken. Along the outer, wave-dominated coast of Maine, erosion is episodic, occurring when large storms raise water levels to new heights. Along the inner, tide-dominated coast, erosion occurs more frequently because unconsolidated sediments are exposed at low elevations in bedrock features. The shell midden archaeological sites of the Boothbay, Maine region are situated in the most rapidly eroding areas; therefore, it can be reasoned that localities without cultural deposits were never occupied. On the other hand, coastal erosion is widespread enough to insure that sites have been exposed to discovery by archaeological survey. Settlement pattern analysis of the study area is, therefore, not biased by differential preservation or discovery of archaeological sites.     

Were the hydraulic parameters of Precambrian rivers different?

Palaeohydraulic estimates have been made using time-tested standard empirical formula involving channel dimensions, especially channel depth, in four Indian Proterozoic fluvial formations. These are the Mesoproterozoic Ramdurg, younger Mesoproterozoic Muchkundi and Neoproterozoic Cave Temple Arenite in Karnataka, and Upper Rewa Sandstone in central India. The basic data came from direct measurement of decompacted thicknesses of completely preserved channel-fills or bedforms, and more commonly of cross-sets. The result, in combination with data derived by others in a similar way from a few other Precambrian fluvial formations helps to provide a new insight into the palaeohydraulics of Precambrian rivers.River gradients appear to have been steeper during the Precambrian; the possibly continuous range of variation in river gradients from alluvial fans to the plains, as a whole shifted to higher values during the Precambrian epoch. The likely reason is a greater possibility of sediment bypassing on vegetation-free land. Concomitant downstream increase in discharge was enhanced in Precambrian rivers due to lack of withdrawal of groundwater through biogenic activity. Precambrian rivers were commonly ephemeral, but downstream the ephemerality index was reduced and some rivers might have been perennial where they debouched into standing bodies of water. The Precambrian river deposits studied generally had smaller width and depth with respect to Phanerozoic and modern rivers, possibly due to unstable substratum causing surface run-off tended to be impelled along multiple independent minor channels.     

Ecological stability during the LGM and the mid-Holocene in the Alpine Steppes of Tibet?

Arid and Alpine ecosystems are known for extreme environmental changes during the Late Quaternary. We hypothesize that the world's largest Alpine arid ecosystem however, the Alpine Steppes of the Tibetan highlands, remained ecologically stable during the LGM and the mid-Holocene. This hypothesis is tested by distributional range of plant species, plant life forms and rate of endemism. The set of character species has a precipitation gradient between 50 and 350 mm/a, testifying for resilience to precipitation changes. 83% of the species have a wider vertical range than 1000 m used as a proxy for resilience to temperature changes. 30% of the species are endemic with 10 endemic genera, including plate-shaped cushions as a unique plant life form. These findings are in line with palaeo-ecological proxies (δ¹⁸O, pollen) allowing the assumption that Alpine Steppes persisted during the LGM with 3 to 4 K lower summer temperatures.During the mid-Holocene, forests could have replaced Alpine Steppes in the upper catchments of the Huang He, Yangtze, Mekong, Salween and Yarlung Zhangbo, but not in the interior basins of the north-western highlands, because the basins were then flooded, suppressing forests and supporting the environmental stability of this arid Alpine grassland biome.     

Did natural fission of 235U in the earth lead to formation of the supercontinent Columbia?

Steady decline in the percentage of 235U in terrestrial uranium made natural fission impossible after about 1.8 Ga.Fission before 1.8 Ga disturbed the lead isotope system at various places worldwide,su...     

Curating the “Third Place”? Coworking and the mediation of creativity

Coworking spaces (CWS) and the associated practice of coworking, have emerged in numerous forms and various urban contexts to critically challenge traditional concepts of the workplace and location of creative work, while simultaneously confronting the way in which creative workers interact with and relate to each other as well as with space and to place. Heralded as a solution to increasingly atomised work patterns, CWS are imagined and presented as spaces of serendipitous encounter, spontaneous exchange and collaboration. Nonetheless, little is known about how coworking positively supports workers and how coworking relates to wider urban transformation processes has been largely un-researched. This paper contributes to a critical discussion through empirical analysis of a project aimed at establishing new creative CWS in city-centre locations across SE England. The study adopts a novel approach using Q-methodology. Motivations for coworking and benefits (or dis-benefits) of co-location are assessed, as is the extent to which coworking facilitates interactional effects and wider neighbourhood interactions. In particular, the role of the CWS manager as “mediator” is explored. Coworker benefits relate primarily to peer-interaction and support rather than formal collaboration. While CWS managers play a key connecting role, also ensuring coworker complementarity and compatibility, the coworker profile (motivations, needs, experiences) ultimately influences outcomes. The study cautions against the use of CWS as “quick fix” urban renewal tools, with little indication that the benefits of coworking reach beyond immediate members or that linkages are easily established between coworkers and local (resident or business) communities.     

How do uncertainties of structure refinements influence the accuracy of the prediction of enthalpy of formation? Examples on muscovite and natrolite

A method to predict the enthalpy of formation is based on the parameter _HO^2-cation (comp) (Vieillard 1982; Vieillard and Tardy 1988a). The calculation of this parameter requires the knowledge of cristallographical and optical properties of minerals (refractive index, molar volume, average distances and shortest bond lengths of cation-oxygens in all sites, existence of hydrogen bonding, presence of a order-disorder in a site of the involved compound). This method has been tested on a great number of minerals and artificial compounds belonging to the system: Li₂O-Na₂O-K₂O-BeO-MgO-CaO-MnO-FeO-Fe₂O₃-Al₂O₃-SiO₂-H₂O (180 minerals) (Vieillard 1994a, b). When several structure refinements of the same mineral are present, several factors such as precision of crystal structure determination, chemical composition, existence of any disorder in a site, presence of hydrogen bonding and estimated standard deviation on bond lengths seem to play an important role in the predication of enthalpy of formation from oxides. Muscovite and natrolite, for which numerous structure refinements are available, are used and discussed in this study.     

Whither the megathrust? Localization of large-scale subduction slip along the contact of a mélange

Long-lived subduction complexes, such as the Franciscan Complex of California, include tectonic contacts that represent exhumed megathrust horizons that collectively accommodated thousands of kilometres of slip. The chaotic nature of mélanges in subduction complexes has spawned proposals that these mélanges form as a result of megathrust displacement. Detailed field and petrographic relationships, however, show that most Franciscan mélanges with exotic blocks formed by submarine landsliding. Field relationships at El Cerrito Quarry in the eastern San Francisco Bay area suggest that subduction slip may have been accommodated between the blueschist facies metagreywacke of the Angel Island nappe above and the prehnite-pumpellyite facies metagreywacke of the Alcatraz nappe below. Although a 100–200 m-thick mélange zone separates the nappes, this mélange is a variably deformed, prehnite-pumpellyite facies sedimentary breccia and conglomerate deposited on the underlying coherent sandstone, so the mélange is part of the lower nappe. A 20–30 m-thick fault zone between the top of the mélange, and the base of the Angel Island nappe displays an inverted metamorphic gradient with jadeite-glaucophane-lawsonite above lawsonite-albite assemblages. This zone has a strong seaward (SW)-vergent shear fabric and hosts ultracataclasite and pseudotachylite. These relationships suggest that significant subduction megathrust displacement at depths of 15–30 km was accommodated within the 20–30 m-thick fault zone. Field studies elsewhere in the Franciscan Complex suggest similar localization of megathrust slip, with some examples lacking mélanges. The narrow megathrust zone at El Cerrito Quarry, its uniform sense-of-shear, and the localization of slip along the contact of, rather than within a mélange, contrast sharply with the predictions of numerical models for subduction channels.     

What is the deepest part of the Vostok ice core telling us?

This review paper is mainly concerned with a geochemical investigation of the deepest part of the Vostok ice core between 3310 m, the depth at which the palaeoenvironmental record present in the ice above is lost, and the bottom of the core about 130 m above subglacial Lake Vostok. Two sections constitute this part of the core.The upper section (3310–3539 m depth) still consists of ice of meteoric origin but subjected to widespread complex deformation. This deformation is analysed in light of a δD–deuterium excess diagram and information on microparticles, crystal sizes and chemical elements distributions in that part of the core. Such ice deformation occurred when the ice was still grounded upstream from Vostok station in a region with subfreezing temperatures.The lower section from 3539 m to the bottom of the core at 3623 m depth is lake ice formed by freezing of subglacial Lake Vostok waters. This is indicated by the isotopic properties (δD, δ¹⁸O and deuterium excess), by electrical conductivity measurements (ECM), crystallography and gas content of the ice. These ice core data together with data on ionic chemistry favour an origin of the lake ice by frazil ice generation in a supercooled (below pressure melting point) water plume existing in the lake followed by accretion and consolidation by subsequent freezing of the host water.The helium profile of this deepest part of the Vostok core is quite unusual and surprising. It has important implications for the interactions between the ice sheet and the lake. Two constrasting scenarios can be satisfactorily constructed so that the lake residence time is not well constrained.