Uelen hunters and artists

Uelen is a settlement inhabited by coastal Chukchi and Yupik people who do not only hunt sea animals but also carve their ivory. Archaeological excavations in Uelen testify that ivory carving has existed there at least since the beginning of our era. When whale hunters and traders came in Uelen in the 19th century, traditional ivory carving turned into an ethnic handicraft. In 1931, Uelen residents were the first to open an ivory carving workshop in Chukotka. In the mid-1930s, they benefited from the valuable help of the Russian artist and art critic Alexander Gorbunkov, who encouraged them to develop their own artistic potential. By the end of the 1930s, Uelen carvers and engravers had acquired their particular artistic style based on their deep knowledge of the Arctic hunters’ customs, expressive images of polar animals, and the natural beauty of walrus tusk. The involvement of a large number of Uelen inhabitants in ivory carving was the main reason for its preservation during the Second World War and the difficult aftermath. New tendencies, including human and folklore themes, emerged in the 1950s-1970s alongside traditional hunting depictions. In the 1980s and 1990s, Uelen artists included in their art some patterns from prehistoric ornaments. While many Chukotka artists are using new creative ways in the 2000s, Uelen carvers in general keep closer to tradition. For them, ivory carving has become a symbol of the vanishing culture of their ancestors.Uelen est un village habité par des résidents tchouktches maritimes et yupik, qui non seulement chassent les mammifères marins mais aussi sculptent leur ivoire. Des fouilles archéologiques entreprises à Uelen ont démontré que l’ivoire y a été sculpté depuis au moins le début de notre ère. Quand les baleiniers et les marchands vinrent à Uelen au 19e siècle, la sculpture traditionnelle de l’ivoire se transforma en artisanat populaire. En 1931, les résidents d’ Uelen furent les premiers à ouvrir un atelier de sculpture de l’ivoire en Tchouktoka. Au milieu des années 1930, ils bénéficièrent de l’aide de l’artiste et critique d’art russe Alexander Gorbunkov qui les encouragea à développer leur propre potentiel artistique. À la fin des années 1930, les sculpteurs avaient acquis un style particulier basé sur leur connaissance des coutumes des chasseurs de l’Arctique, les images expressives des animaux polaires et la beauté naturelle de l’ivoire de morse. La participation de nombreux résidents d’Uelen à la sculpture sur ivoire fut la raison principale de sa préservation durant la Seconde Guerre Mondiale et la dure période de l’après-guerre. De nouvelles tendances, incluant des thèmes humains et folkloriques sont apparus dans les années 1950 à 1970 avec aussi des représentations de chasse traditionnelle. Durant les années 1980 et 1990, les artistes inclurent dans leur art certains motifs d’ornements préhistoriques. Si de nombreux artistes de la Tchoukotka recourent à de nouveaux modes d’expression dans les années 2000, les sculpteurs d’Uelen sont en général plus traditionnels. Pour eux, la sculpture est devenue un symbole de la culture ancestrale en voie de disparition

Counterfeit Pharmaceuticals in China: Could Changes Bring Stronger Protection for Intellectual Property Rights and Human Health?

Although China seeks to improve its image as a legitimate participant in the global intellectual property (“IP”) market, Chinese companies continue to produce more than thirty percent of the counterfeit drugs circulating in the world today. The counterfeit pharmaceutical industry profits from efficient and cost-effective production systems by producing counterfeits at an exceedingly low cost. This poses a serious problem because the production and sale of counterfeit drugs leads to negative economic and social health-related effects. China’s existing penalties for counterfeit pharmaceutical production are considered a mere cost of doing business in China, rather than a deterrent from engaging in counterfeiting. China’s national government has taken several steps to fight against IP infringement, but despite this effort, the growing power and autonomy of local governments has complicated and exacerbated the problem. In order to become a legitimate and reputable force in the international economy, China must take greater steps to limit the production and sale of counterfeit pharmaceuticals. First, China must amend its laws to include penalties that will effectively deter actors from entering the counterfeit market. Second, China must allocate a significant amount of resources to the judicial system to ensure that adjudication is effective and efficient. Third, China must fight localized corruption at its source to increase enforcement of IP rights. Specifically, an agency should be created to target local corruption and to disestablish the counterfeit pharmaceutical market. This agency should have investigative and auditing power and should work to educate both the public and the business community on the problems posed by counterfeit pharmaceuticals and the means used to counter them

On Multiple Einstein Rings

A number of recent surveys for gravitational lenses have found examples of double Einstein rings. Here, we investigate analytically the occurrence of multiple Einstein rings. We prove, under very general assumptions, that at most one Einstein ring can arise from a mass distribution in a single plane lensing a single background source. Two or more Einstein rings can therefore only occur in multi-plane lensing. Surprisingly, we show that it is possible for a single source to produce more than one Einstein ring. If two point masses (or two isothermal spheres) in different planes are aligned with observer and source on the optical axis, we show that there are up to three Einstein rings. We also discuss the image morphologies for these two models if axisymmetry is broken, and give the first instances of magnification invariants in the case of two lens planes.Comment: MNRAS, in press (extra figure included

Description of stochastic and chaotic series using visibility graphs

Nonlinear time series analysis is an active field of research that studies the structure of complex signals in order to derive information of the process that generated those series, for understanding, modeling and forecasting purposes. In the last years, some methods mapping time series to network representations have been proposed. The purpose is to investigate on the properties of the series through graph theoretical tools recently developed in the core of the celebrated complex network theory. Among some other methods, the so-called visibility algorithm has received much attention, since it has been shown that series correlations are captured by the algorithm and translated in the associated graph, opening the possibility of building fruitful connections between time series analysis, nonlinear dynamics, and graph theory. Here we use the horizontal visibility algorithm to characterize and distinguish between correlated stochastic, uncorrelated and chaotic processes. We show that in every case the series maps into a graph with exponential degree distribution P (k) ~ exp(-{\lambda}k), where the value of {\lambda} characterizes the specific process. The frontier between chaotic and correlated stochastic processes, {\lambda} = ln(3/2), can be calculated exactly, and some other analytical developments confirm the results provided by extensive numerical simulations and (short) experimental time series

Relating pseudospin and spin symmetries through charge conjugation and chiral transformations: the case of the relativistic harmonic oscillator

We solve the generalized relativistic harmonic oscillator in 1+1 dimensions, i.e., including a linear pseudoscalar potential and quadratic scalar and vector potentials which have equal or opposite signs. We consider positive and negative quadratic potentials and discuss in detail their bound-state solutions for fermions and antifermions. The main features of these bound states are the same as the ones of the generalized three-dimensional relativistic harmonic oscillator bound states. The solutions found for zero pseudoscalar potential are related to the spin and pseudospin symmetry of the Dirac equation in 3+1 dimensions. We show how the charge conjugation and $\gamma^5$ chiral transformations relate the several spectra obtained and find that for massless particles the spin and pseudospin symmetry related problems have the same spectrum, but different spinor solutions. Finally, we establish a relation of the solutions found with single-particle states of nuclei described by relativistic mean-field theories with scalar, vector and isoscalar tensor interactions and discuss the conditions in which one may have both nucleon and antinucleon bound states.Comment: 33 pages, 10 figures, uses revtex macro

Trialogue on the number of fundamental constants

This paper consists of three separate articles on the number of fundamental dimensionful constants in physics. We started our debate in summer 1992 on the terrace of the famous CERN cafeteria. In the summer of 2001 we returned to the subject to find that our views still diverged and decided to explain our current positions. LBO develops the traditional approach with three constants, GV argues in favor of at most two (within superstring theory), while MJD advocates zero.Comment: Version appearing in JHEP; 31 pages late

Algebraic treatment of the confluent Natanzon potentials

Using the so(2,1) Lie algebra and the Baker, Campbell and Hausdorff formulas, the Green's function for the class of the confluent Natanzon potentials is constructed straightforwardly. The bound-state energy spectrum is then determined. Eventually, the three-dimensional harmonic potential, the three-dimensional Coulomb potential and the Morse potential may all be considered as particular cases.Comment: 9 page

Approximations for many-body Green's functions: insights from the fundamental equations

Several widely used methods for the calculation of band structures and photo emission spectra, such as the GW approximation, rely on Many-Body Perturbation Theory. They can be obtained by iterating a set of functional differential equations relating the one-particle Green's function to its functional derivative with respect to an external perturbing potential. In the present work we apply a linear response expansion in order to obtain insights in various approximations for Green's functions calculations. The expansion leads to an effective screening, while keeping the effects of the interaction to all orders. In order to study various aspects of the resulting equations we discretize them, and retain only one point in space, spin, and time for all variables. Within this one-point model we obtain an explicit solution for the Green's function, which allows us to explore the structure of the general family of solutions, and to determine the specific solution that corresponds to the physical one. Moreover we analyze the performances of established approaches like $GW$ over the whole range of interaction strength, and we explore alternative approximations. Finally we link certain approximations for the exact solution to the corresponding manipulations for the differential equation which produce them. This link is crucial in view of a generalization of our findings to the real (multidimensional functional) case where only the differential equation is known.Comment: 17 pages, 7 figure

Non-linearity and related features of Makyoh (magic-mirror) imaging

Non-linearity in Makyoh (magic-mirror) imaging is analyzed using a geometrical optical approach. The sources of non-linearity are identified as (1) a topological mapping of the imaged surface due to surface gradients, (2) the hyperbolic-like dependence of the image intensity on the local curvatures, and (3) the quadratic dependence of the intensity due to local Gaussian surface curvatures. Criteria for an approximate linear imaging are given and the relevance to Makyoh-topography image evaluation is discussed