The concentration of power in the market for contemporary art: an empirical analysis of ArtReview’s “Power 100”

Art experts and intermediaries play a crucial role in art markets. Artworks are goods whose quality is difficult to determine. Therefore, it seems necessary to restrict competition in the market for art experts to a certain extent, but not too much, in order to provide high-quality know-how. This paper contains an empirical analysis of the extent to which the market for art experts is concentrated. To this end, different methods for measuring the market concentration are applied, with an emphasis on the determination of the distribution function of a newly defined Power Index. The annual Power 100 ranking in the magazine ArtReview from 2002 to 2019 is used to study concentration in the art expert market. The results reveal not only several indications of a hierarchically tiered, but also highly concentrated market power in this market. First, the selection of nationalities of the so-called power members is biased, given that particularly Americans and western Europeans are overrepresented in relation to their world population shares, in contrast to underrepresented Asians, Africans, and Latin Americans. Second, although there is considerable variability in the low tiers of the ranking, the top positions in the rankings are very stable, as shown by the Power Dominance Index. Third, the main empirical result of this paper is that the Top 99 ranking positions follow an extreme value Fréchet distribution with a fat tail. This is interpreted as an indication of excessive concentration on the highest tier of art experts. Liberalizing the art expert market to a certain extent may provide more diversity and less dominance in high-end art markets.

Automated detection and analysis of surface calving waves with a terrestrial radar interferometer at the front of Eqip Sermia, Greenland

Glacier calving is a key dynamical process of the Greenland Ice Sheet and a major driver of its increasing mass loss. Calving waves, generated by the sudden detachment of ice from the glacier terminus, can reach tens of meters in height and provide very valuable insights into quantifying calving activity. In this study, we present a new method for the detection of source location, timing, and magnitude of calving waves using a terrestrial radar interferometer. This method was applied to 11 500 1 min interval acquisitions from Eqip Sermia, West Greenland, in July 2018. Over 7 d, more than 2000 calving waves were detected, including waves generated by submarine calving, which are difficult to observe with other methods. Quantitative assessment with a wave power index (WPI) yields a higher wave activity (+49 %) and higher temporally cumulated WPI (+34 %) in deep water than under shallow conditions. Subglacial meltwater plumes, occurring 2.3 times more often in the deep sector, increase WPI and the number of waves by a factor of 1.8 and 1.3, respectively, in the deep and shallow sector. We therefore explain the higher calving activity in the deep sector by a combination of more frequent meltwater plumes and more efficient calving enhancement linked with better connections to warm deep ocean water.

An Analytical Solution for Non-Darcian Flow on a Constant Head Packer Test in the Interlayer Staggered Zone

Groundwater flow in an aquifer has frequently been found to be non-Darcian by performing in situ tests. A novel analytic model is proposed in this study for describing the unsteady non-Darcian flow in a confined aquifer by taking advantage of the observed flow rate and injection pressure during the constant head packer test. A linearization approximation of the Izbash equation is used to approximate the nonlinear term in the governing equation. This analytic model is applied to describe the non-Darcian flow in the interlayer staggered zone at the Baihetan hydropower station, China. The test results inversed by the genetic algorithm show that non-Darcian flow happened during the test under the injection pressure 0.3 MPa with the power index n is 1.278, non-Darcian hydraulic conductivity k 1 is 1.613 × 10 − 5 cm/s and the specific storage S s is 9.757 × 10 − 5 m-1, respectively. The sensitivity analysis indicated that when the power index n or the specific storage S s is larger, and the hydraulic head will increase more slowly and needs longer to stabilize, but the non-Darcian hydraulic conductivity k 1 shows the opposite trend. Moreover, the hydraulic head is more sensitive to the power index n compared to other parameters at late times. The findings of this study reveal the non-Darcian flow during the constant head packer test and provide a simple and fast way to estimate parameters for more accurate seepage field simulation.

Global Distribution of the Solar Wind Speed Reconstructed from Improved Tomographic Analysis of Interplanetary Scintillation Observations between 1985 and 2019

Computer-assisted tomography (CAT) for interplanetary scintillation (IPS) observations enables the determination of the global distribution of solar wind speed. We compared solar wind speeds derived from the CAT analysis of IPS observations between 1985 and 2019 with in situ observations conducted by the near-Earth and Ulysses spacecraft. From this comparison, we found that solar wind speeds from the IPS observations for 2009–2019 were systematically higher than the in situ observations, whereas those for the period until 2008 were in good agreement with the in situ observations. Further, we found that the discrepancy between IPS and the in situ observations is improved by changing the power index of the empirical relation between the solar wind speed and density fluctuations. The CAT analysis using an optimal value for the power index determined from the comparison between IPS and in situ observations revealed long-term variations in the solar wind speed distribution over three cycles, leading to a better understanding of the time-varying global heliosphere. We found that polar solar winds become highly anisotropic at the Cycle 24/25 minimum, which is a peculiar aspect of this minimum. The IPS observations showed general agreement with the Parker Solar Probe observations around the perihelion of Orbit 1; this supports the reliability of the CAT analysis. The results of this study suggest that the physical properties of solar wind microturbulence may vary with a long-term decline in the solar activity, which provides important implication on the solar wind acceleration.

Országmárka-rangsorok a Covid-19 világjárvány idején – „Az az egy fontos: legyetek jók most!”

A termékek és szolgáltatások világában jó ideje megszokottak a márkarangsorok: a top100-as globális márkalistát többek közt elkészíti az Interbrand és a BrandZ-Kantar-WPP is. Az Interbrand 2020-as listájának első öt helyén például az Apple, az Amazon, a Microsoft, a Google és a Samsung áll, őket követi az első, nem technológiai márka, a Coca-Cola. De a BrandZ-Kantar-WPP 2020-as rangsora esetén is hasonló a helyzet, ott az első öt helyezett sorrendje: Amazon, Apple, Google, Microsoft, Visa. A klasszikus márkarangsorokhoz hasonlóan az országmárkákra is rendelkezésre állnak már toplisták. Sőt, szinte minden évben megjelenik legalább egy új ilyen. Van már Anholt Nation Brands Index, FutureBrand Country Brand Index, Anholt Good Country Index, Bloom Consulting Country Brand Ranking (Tourism Edition, illetve Trade Edition), Young&Rubicam Best Countries, Reputation Institute Country RepTrak és Global Soft Power Index is. Ezek mindegyikét lehetetlen taglalni egyetlen cikk keretei között, és nem is mindegyiknek van annyira friss országmárka-rangsora, ami már a Covid-19 járványidőszak alatt született, ezért most csak az első hármat vettük górcső alá közülük. A publikáció egyik célja az, hogy magyar nyelven először bemutassa ezek módszertanát, dimenzióit és faktorait, illetve az egyes rangsorok eredményeit, különös tekintettel arra, hogy 2020-ban miként változtak. Az írás másik célja, hogy rámutasson arra, hogy a jó országmárka, a jó országimázs alapja voltaképp nem más, mint maga a jó ország, pontosan ugyanúgy, ahogy egy klasszikus márka esetében is a kiindulópont a jó termék és szolgáltatás.

Game-Theoretic Dynamic Procedure for a Power Index under Relative Symmetry

In many operational processes, a suitable combination of participating elements has a huge impact throughout the entire process. In the real environment, however, many combinations show less than expected results in the initial stage. In consideration of the many subjective and objective factors such as equipment, time, capital, materials, and so forth, it seems that the aforementioned combinations cannot be used to re-configure. It is important that these initial unsatisfactory combinations can gradually approach some equilibrium states or results through some rolling adjustment processes. In order to improve the above problem, this study attempts to use a game-theoretic dynamic procedure to establish a mechanism that can be dynamically modified under relative symmetry at any time during operational processes. Under such a dynamic procedure, an undesirable combination of participating elements can gradually approach a useful combination.

Analysis of the Relationship between Human Development Index and Regional Development of West Sulawesi Province

This study aims to analyze the relationship between the human development index and the regional development of West Sulawesi Province. This study uses panel data analysis that combines time series-cross section data and uses the Two Stage Least Square (2SLS) method. The type of data in this study is secondary data taken from the Central Statistics Agency (BPS) of West Sulawesi. The variables of the human development index are life expectancy, average length of schooling, expected length of schooling and purchasing power index. While the variables of regional development are poverty, unemployment, regional inequality and GRDP. The results of the analysis using the 2SLS method. In the HDI equation, the PW variable partially has a negative but not significant effect on the HDI for =5%. However, if for =20% PW has a negative and significant effect on HDI. While in the PW equation, the HDI variable partially has a negative but not significant effect on PW for = 5%. The R2 in the HDI equation is 97.5% and the remaining 2.5% which shows that the influence of PW, Life Expectancy, Average Years of Schooling, Expected Years of Schooling, and Purchasing Power Index together have an effect on HDI. While in the PW equation, the determination of R2 is 99.2% and the remaining 0.8% which shows HDI, Poverty Level, Unemployment Rate, Regional Inequality and Gross Regional Domestic Product together affect PW. So, there is a simultaneous relationship between the Human Development Index and Regional Development

Non Uniqueness of Power-Law Flows

We apply the technique of convex integration to obtain non-uniqueness and existence results for power-law fluids, in dimension $$d\ge 3$$ d ≥ 3 . For the power index q below the compactness threshold, i.e. $$q \in (1, \frac{2d}{d+2})$$ q ∈ ( 1 , 2 d d + 2 ) , we show ill-posedness of Leray–Hopf solutions. For a wider class of indices $$q \in (1, \frac{3d+2}{d+2})$$ q ∈ ( 1 , 3 d + 2 d + 2 ) we show ill-posedness of distributional (non-Leray–Hopf) solutions, extending the seminal paper of Buckmaster & Vicol [10]. In this wider class we also construct non-unique solutions for every datum in $$L^2$$ L 2 .

The state of health of students majoring in "physical therapy" of the Kharkiv State Academy of Physical Culture

Purpose: to analyze the state of health of students studying at the Kharkiv State Academy of Physical Culture, majoring in "Physical Therapy". Material and methods: the study was conducted on the basis of the Department of Medical Disciplines and Health of the Kharkiv State Academy of Physical Culture. The study involved 90 students, including 49 female students and 41 male students. The state of health of students was studied according to the method of GL Apanasenko. Results: Only 4.08% of students were classified as safe, while 95.92% of students were outside the safe level. The share of values of the Kettle index corresponding to a harmonious physique was 83.93% of boys and 30.61% of girls. The average values of the Robinson index were observed in 51.22% of boys and 48.98% of girls. Among the studied students, the average values of the life index are 21.95% of boys and 36.59% of girls. Indicators of the power index among boys was 31.71% - at a low level, girls tended to high levels of the indicator - 22.45%. During the Martine-Kushelevsky test, it was found that 51.22% of boys have a low score, while among girls no case of a low score was recorded. Conclusions: Thus, the assessment of students' physical health indicates that it is mostly unsatisfactory. Due to the long-term development of students during the study period, they are more vulnerable to various adverse effects, which will lead to disruption of the process of adaptation and the development of a number of diseases.