Strategically Equivalent Contests

Using a two-player Tullock-type contest, we show that intuitively and structurally different contests can be strategically equivalent. Strategically equivalent contests generate the same best response functions and, as a result, the same equilibrium efforts. However, strategically equivalent contests may yield different equilibrium payoffs. We propose a simple two-step procedure to identify strategically equivalent contests. Using this procedure, we identify contests that are strategically equivalent to the original Tullock contest, and provide new examples of strategically equivalent contests. Finally, we discuss possible contest design applications and avenues for future theoretical and empirical research

A generalized Tullock contest

We construct a generalized Tullock contest under complete information where contingent upon winning or losing, the payoff of a player is a linear function of prizes, own effort, and the effort of the rival. This structure nests a number of existing contests in the literature and can be used to analyze new types of contests. We characterize the unique symmetric equilibrium and show that small parameter modifications may lead to substantially different types of contests and hence different equilibrium effort levels

An Experimental Investigation of Colonel Blotto Games

"This article examines behavior in the two-player, constant-sum Colonel Blotto game with asymmetric resources in which players maximize the expected number of battlefields won. The experimental results support all major theoretical predictions. In the auction treatment, where winning a battlefield is deterministic, disadvantaged players use a 'guerilla warfare' strategy which stochastically allocates zero resources to a subset of battlefields. Advantaged players employ a 'stochastic complete coverage' strategy, allocating random, but positive, resource levels across the battlefields. In the lottery treatment, where winning a battlefield is probabilistic, both players divide their resources equally across all battlefields." (author's abstract)"Dieser Artikel untersucht das Verhalten von Individuen in einem 'constant-sum Colonel Blotto'-Spiel zwischen zwei Spielern, bei dem die Spieler mit unterschiedlichen Ressourcen ausgestattet sind und die erwartete Anzahl gewonnener Schlachtfelder maximieren. Die experimentellen Ergebnisse bestätigen alle wichtigen theoretischen Vorhersagen. Im Durchgang, in dem wie in einer Auktion der Sieg in einem Schlachtfeld deterministisch ist, wenden die Spieler, die sich im Nachteil befinden, eine 'Guerillataktik' an, und verteilen ihre Ressourcen stochastisch auf eine Teilmenge der Schlachtfelder. Spieler mit einem Vorteil verwenden eine Strategie der 'stochastischen vollständigen Abdeckung', indem sie zufällig eine positive Ressourcenmenge auf allen Schlachtfeldern positionieren. Im Durchgang, in dem sich der Gewinn eines Schlachtfeldes probabilistisch wie in einer Lotterie bestimmt, teilen beide Spieler ihre Ressourcen gleichmäßig auf alle Schlachtfelder auf." (Autorenreferat

Endocrine disruptors in the pathogenesis of socially significant diseases such as diabetes mellitus, malignant neoplasms, cardiovascular diseases, pathology of the reproductive system

Some environmental chemicals capable of interfering with the endocrine regulation of energy metabolism and the structure of adipose tissue in the function of the reproductive, immune, cardiovascular and other systems are called endocrine disruptors or disruptors. According to the WHO definition, the term «endocrine disruptors» means: «Exogenous substances or mixtures thereof that alter the function (s) of the endocrine system and, as a result, cause adverse effects in the intact organism or in its offspring, or (sub) population.» This includes compounds to which humanity is exposed in daily life as a result of their use in pesticides, herbicides, industrial and household products, plastics, detergents, refractory impregnations and as ingredients in personal care products. This review will present the latest scientific data on various ERs, such as persistent organic pollutants (POPs): pesticides (mirex, chlordecane, endosulfan, hexachlorobenzene-HCB dichlorodiphenyltrichloroethane-DDT and its metabolites), industrial chemicals (bisphenol A, polybrominated ether -PBDE, polychlorinated biphenyls-PCB, nonylphenol, dioxins, perfluorooctanoic acid-PFOA, phthalates), pharmaceuticals (diethylstilbestrol-DES). ERs are regarded as compounds that cause obesity, since they have the ability to influence cellular processes associated with adipose tissue, initiating changes in lipid metabolism and adipogenesis. Analysis of scientific materials on this issue indicates that ERs are ubiquitous in the environment and have a detrimental effect on the health of animals and mankind. The scientific and practical interest in this article is based on the growing statistics of the development of such socially significant pathologies as obesity and related diseases, including diabetes mellitus, metabolic syndrome, cardiovascular diseases, menstrual irregularities, as well as cancer and infertility, for of which obesity is a risk factor

Best-of-Three Contests: Experimental Evidence

We conduct an experimental analysis of a best-of-three Tullock contest. Intermediate prizes lead to higher efforts, while increasing the role of luck (as opposed to effort) leads to lower efforts. Both intermediate prizes and luck reduce the probability of contest ending in two rounds. The patterns of players‟ efforts and the probability that a contest ends in two rounds is consistent with „strategic momentum‟, i.e. momentum generated due to strategic incentives inherent in the contest. We do not find evidence for „psychological momentum‟, i.e. momentum which emerges when winning affects players‟ confidence. Similar to previous studies of contests, we find significantly higher efforts than predicted and strong heterogeneity in effort between subjects

Estimated Inpatient Hospital Stay in Individual Wards: Guidelines on Radiation Safety after Radioiodine Therapy

Radionuclide therapy safety requirements are regulated by the Russian Radiation Safety Standards (RRSS), which state the maximum allowed radionuclide activity in the body and the equivalent dose rate (EDR) of gamma radiation. Therefore, it is necessary to estimate the time of an inpatient hospital stay in specially designed radionuclide therapy wards. The article presents the findings of individual 131I biokinetics studies in 64 patients admitted to radioiodine therapy of thyrotoxicosis and differentiated thyroid cancer. We developed a method to calculate the time interval to reach the EDR of 20μSv/h and the recommended EDR of 3 and 0.3μSv/h for adults and children, respectively. It is based on the measurement of the 131I excretion constant. Keywords: Radioiodine therapy, Radiation safety, Guidelin

Рис. 6. Область шеи через 3 мес после радиойодтерапии.

Osteogenesis imperfecta (OI) – is a group of genetically disorders, which are charaterized by a disturbed bone formation. In turn, the excess of thyroid hormones in Graves' disease (GD) also posses a negative effect on bone tissue, thereby aggravating OI. That requires from the endocrinologist the most careful management of patients with the combination of these pathologies. In this article, we present a unique clinical case of a combination of GD and OI

Nasolacrimal Duct Obstruction Secondary to Radioactive Iodine-131 Therapy for Differentiated Thyroid Cancer

Deterministic effects of medical exposure to ionising radiation can be associated with both the effectiveness of treatment and adverse drug reactions to it. The latter may drastically deteriorate the quality of life of a patient after radionuclide therapy. In addition, the regulations of the Russian Federation require indicating the effective dose of radiation as a measure of damage (risk), but the presence of a deterministic effect in individual organs and tissues complicates monitoring and recording patient exposure doses. The aim of the study was to investigate the effect of radiopharmaceuticals containing 131I on the development of secondary nasolacrimal duct obstruction (NLDO). Materials and methods: the study of secondary NLDO predictors analysed medical history data, post-therapy head-and-neck scintigrams, and methods to prepare patients for treatment. It involved sodium iodide, 131I, formulated as a solution (marketing authorisation number: FS-002065) by the FSUE Federal Center of Nuclear Medicine Projects Design and Development of the FMBA of Russia. Results: the authors unambiguously localised the lacrimal ducts in post-therapy 131I scintigrams of the head and neck and quantified 131I uptake ratios for the lacrimal duct area. Also, they identified a set of NLDO predictors: the age of a patient, the administered activity, the administration of recombinant human thyroid-stimulating hormone, the 131I uptake ratio, etc. The article describes a method for identifying the groups at risk of NLDO following radioiodine therapy for differentiated thyroid cancer. Conclusions: secondary NLDO is a deterministic effect of 131I exposure. The authors have developed a new method for predicting secondary NLDO by a combination of the patient’s individual parameters and treatment plan; the identified predictors help to personalise radioiodine therapy. The authors suggest the following: to include information on secondary NLDO as a complication of therapy to the SmPC section on undesirable effects; to develop approaches to secondary NLDO prevention; and to improve the algorithms for reporting adverse events in case of delayed manifestation and those for following patients up in the medical organisations having administered the radiopharmaceutical or in other medical organisations being applied to for medical care afterwards

Transforming growth factor β1 (TGF-β1) in patients with endocrine ophthalmopathy and Graves’ disease: A predictor of treatment efficiency

Current therapeutic approaches to the treatment of endocrine ophthalmopathy (EOP) are based on nonspecific immunosuppression with glucocorticosteroids (GCs) and radiation therapy of the eye orbits. However, some patients exhibit resistance to the treatment. In a previous study, we have detected high levels of soluble cytokine receptors: sTNFα-R1, sTNFα-R2, sIL-2R, and the TGF-β1 cytokine in euthyroid patients with long-lasting non-treated EOP and Graves’ disease (GD). TGF-β1 level was significantly higher in the patients with EOP compared to healthy individuals, and increased with prolonged EOP duration, thus suggesting activation of the factors regulating immune system which promote suppression of the autoimmune process. The aim of this work was to study the dynamics of TGF-β1 and cytokine receptors: sTNFα-R1, sTNFα-R2, sIL-2R in the course of immunosuppressive therapy with high doses of GCs, as possible predictors of treatment efficacy. The study included 49 patients (98 eye orbits) with GD of euthyroid state and subclinical thyrotoxicosis, and the persons with EOP in active phase, who had not previously treatment for EOP. Concentrations of TGF-β1 cytokine, sTNFα-RI and sTNFα-R2, sIL-2R, antibodies to the thyroid-stimulating hormone receptor (rTSH), free fractions of thyroxine (fT4) and triiodothyronine (fT3), TSH in blood serum were determined in blood serum. Ultrasound examination of the thyroid gland (ultrasound of the thyroid gland), multi-layer computed tomography (MSCT)/magnetic resonance imaging (MRI) of the orbits were also performed. The patients were administered immunosuppressive therapy with high doses of HCs (methylprednisolone) in the course of pulse therapy, at a standard dosage of 4500-8000 mg, taking into account the severity and activity of the EOP clinical manifestations. The examination was carried out 3, 6, 12 months after starting the treatment. 3 and 6 months after the GC administration, more than 30% of patients remained resistant to treatment. The levels of TGF-β1 did not change significantly in the patients with positive EOP dynamics. In the patients resistant to GC treatment, the level of TGF-β1 was significantly decreased compared with patients who showed positive clinical dynamics. The level of sNFR1 and sNFaR2 did not change significantly. There were no significant differences in the levels of antibodies to rTSH, thyroid hormones in the patients resistant to GC treatment and with positive dynamics.Immunosuppressive therapy with high-dose of methylprednisolone in pulse therapy regimen showed high efficacy and good tolerability, while some patients remain resistant to treatment. Lower levels of TGF-β1 cytokine at initial time and during the treatment allow usage of TGF-β1 levels as a biomarker of the activity of the process, treatment efficiency, and prognosis of the disease. Activation of TGF-β1, a fibroblast growth factor, may contribute to the development of fibrosis, strabismus, and diplopia