Relational Contracts and the Economic Well-Being of Nations

Informal long-term relationships and mutual confidence play a crucial role in modern economies in at least two dimensions. First, the performance of firms is strongly affected by their capacity to solve organizational questions effectively and this capacity is apparently strongly related to their ability to maintain informal long-term relationships. Second, countries that are better at maintaining unwritten agreements and where interactions are more strongly guided by a sense of trust fare better in terms of economic welfare than others. This paper provides a simple general equilibrium model which reconciles these two findings: we offer a micro-founded explanation of how the trust that prevails in an economy gets transmitted into higher economic well-being and we thereby highlight the role of managers with low time preference. Our analysis builds on the model of Antràs and Helpman (2004) and a formalization of the notion of relational contracting developed in Baker, Gibbons and Murphy (2002).relational contracting, theory of the firm, aggregate welfare, firm heterogeneity

The Polish Church Examines Its Conscience

Focuses on the conference entitled `Examination of Conscience: the Polish church Confronts Anti-Semitism, 1989-1999,\u27 held on January 20 at the Loyola Marymount University in Los Angeles, California

Research on vibration source separation of the Stirling engine based on the Fast ICA algorithm

In this paper we employed the Fast ICA Independent Component Analysis algorithm for decomposing vibration data in operational Stirling engine. Accurate separating vibration signals containing noises allows for the early fault detection of the Stirling engine and by this guarantees the more reliable work of this engine and its better performance. The results show that using the Fast ICA blind source separation algorithm enhances the quality of obtained fault detection information, which is more precise and makes the fault diagnosis more effective

Magnetoelectric coupling in polycrystalline FeVO4

We report coupling between magnetic and electric orders for antiferromagnetic polycrystalline FeVO4 in which magnetism-induced polarization has been recently found in noncollinear antiferromagnetic state below the second antiferromagnetic phase transition at TN2=15.7K. In this low symmetry phase space group P-1, the magnetic field dependence of electric polarization evidences a clear magnetoelectric coupling in the noncollinear spin-configured antiferromagnetic phase. The discontinuity of magnetodielectric effect observed at the vicinity of the polar to nonpolar transition evidences competition between different magnetodielectric couplings in the two different antiferromagnetic states. The existence of thermal expansion anomaly near TN2 and magnetostriction effect support magnetoelastically mediated scenario of the observed magnetoelectric effect.Comment: 4 pages, 6 figures, Phys. Rev. B 80, 172103 (2009

Revisit of non-linear Landau damping for electrostatic instability driven by blazar-induced pair beams

We revisit the effect of non-linear Landau (NL) damping on the electrostatic instability of blazar-induced pair beams, using a realistic pair-beam distribution. We employ a simplified 2D model in ${\bf k}$-space to study the evolution of the electric-field spectrum and to calculate the relaxation time of the beam. We demonstrate that the 2D model is an adequate representation of the 3D physics. We find that non-linear Landau damping, once it operates efficiently, transports essentially the entire wave energy to small wavenumbers where wave driving is weak or absent. The relaxation time also strongly depends on the IGM temperature, $T_\mathrm{IGM}$, and for $T_\mathrm{IGM}\ll10$ eV, and in the absence of any other damping mechanism, the relaxation time of the pair beam is longer than the inverse Compton (IC) scattering time. The weak late-time beam energy losses arise from the accumulation of wave energy at small $k$, that non-linearly drains the wave energy at the resonant $\mathbf{k}$ of the pair-beam instability. Any other dissipation process operating at small $k$ would reduce that wave-energy drain and hence lead to stronger pair-beam energy losses. As an example, collisions reduce the relaxation time by an order of magnitude, although their rate is very small. Other non-linear processes, such as the modulation instability, could provide additional damping of the non-resonant waves and dramatically reduce the relaxation time of the pair beam. An accurate description of the spectral evolution of the electrostatic waves is crucial for calculating the relaxation time of the pair beam

Визначення кількісного вмісту основаних груп біологічно активних речовин у серіях плодів калини звичайної

Aim. To determine the quantitative content of the main groups of biologically active substances (BAS) in batches of Viburnum opulus fruits using pharmacopeial methods for their subsequent use in the standardization of the plant raw material.Materials and methods. For the study, 6 batches of air-dried Viburnum opulus fruits crushed to a particle size of 1 – 2 mm and harvested in different regions of Ukraine in the mass fruiting phase in October-November 2020 were used. The quantitative determination of polyphenols and tannins was performed using the spectrophotometric method at a wavelength of 760 nm calculated with reference to pyrogallol and dried substance. The total amount of hydroxycinnamic acids was determined according to the method of the SPhU (State Pharmacopoeia of Ukraine) 2.0 described in the monograph “Kidney TeaN” calculated with reference to rosemary acid. The total amount of organic acids was determined by the titrimetric method according to the method of the monograph of the SPhU 2.1 “Rose hipsN” calculated with reference to malic acid.Results and discussion. The quantitative content of polyphenols (calculated with reference to pyrogallol and dried substance) in batches of Viburnum opulus fruits varied by about 1.4 times from 1.74 ± 0.01 % to 2.36 ± 0.01 %. According to the results obtained, the quantitative content of tannins (calculated with reference to pyrogallol and dried substance) in batches of Viburnum opulus fruits varied by 1.7 times from 0.73 ± 0.01 % to 1.23 ± 0.01 %. The quantitative content of the total amount of hydroxycinnamic acids calculated with reference to rosemary acid in batches of Viburnum opulus fruits ranged by 1.2 times from 3.96 ± 0.01 % to 4.73 ± 0.01 %. The quantitative content of the total amount of organic acids calculated with reference to malic acid in batches of Viburnum opulus fruits fluctuated more than 1.3 times from 6.80 ± 0.01 % to 9.08 ± 0.01 %.Conclusions. The quantitative content of the main groups of biologically active substances has been determined in 6 batches of Viburnum opulus fruits harvested in different regions of Ukraine using pharmacopoeial methods: polyphenols (varied by 1.4 times), tannins (varied by 1.7 times), the total amount of hydroxycinnamic (varied by 1.2 times), and the total amount of organic acids (varied by 1.3 times) calculated with reference to dried substance. The content of the groups of biologically active substances in batches of Viburnum opulus fruits slightly correlates with the place of the raw material harvesting. Thus, the selected methods of the SPhU 2.0 are quite suitable for determining the quantitative content of polyphenols, tannins and of the total amount of hydroxycinnamic and organic acids in batches of Viburnum opulus fruits; they can be used in further studies to standardize the raw material.Мета. Визначити кількісний вміст основних груп біологічно активних речовин (БАР) у серіях плодів калини звичайної з використанням фармакопейних методик для подальшого їх застосування у стандартизації сировини.Матеріали та методи. Для дослідження використовували 6 серій повітряно сухих подрібнених до розміру частинок 1 – 2 мм плодів калини звичайної, заготовлених у різних регіонах України у фазі масового плодоносіння в жовтні-листопаді 2020 року. Кількісне визначення поліфенолів і танінів проводили за допомогою спектрофотометричного методу за довжини хвилі 760 нм у перерахунку на пірогалол і суху речовину, суми гідроксикоричних кислот – за методикою монографії Державної фармакопеї України 2.0 «Нирковий чайN» у перерахунку на розмаринову кислоту, суми органічних кислот проводили титриметричним методом за методикою монографії «Шипшини плодиN» Державної фармакопеї України 2.1 у перерахунку на яблучну кислоту.Результати та їх обговорення. Кількісний вміст поліфенолів (у перерахунку на пірогалол та суху речовину) у серіях плодів калини звичайної варіював майже в 1,4 раза – від 1,74 ± 0,01 % до 2,36 ± 0,01 %. Кількісний вміст танінів (у перерахунку на пірогалол та суху речовину) у серіях плодів калини звичайної варіював в 1,7 раза – від 0,73 ± 0,01 % до 1,23 ± 0,01 %. Кількісний вміст суми гідроксикоричних кислот у перерахунку на розмаринову кислоту в серіях плодів калини звичайної коливався в 1,2 раза – від 3,96 ± 0,01 % до 4,73 ± 0,01 %. Кількісний вміст суми органічних кислот у перерахунку на яблучну кислоту в серіях плодів калини звичайної коливався в більше ніж 1,3 раза – від 6,80 ± 0,01 % до 9,08 ± 0,01 %.Висновки. У 6 серіях плодів калини звичайної, заготовлених у різних регіонах України, з використанням фармакопейних методик визначено кількісний вміст основних груп БАР: поліфенолів (коливався в 1,4 раза), танінів (коливався в 1,7 раза), суми гідроксикоричних кислот (коливався в 1,2 раза) та суми органічних кислот (коливався в 1,3 раза) у перерахунку на суху сировину. Кількісний вміст груп БАР у серіях плодів калини звичайної незначно корелює з місцем заготівлі сировини. Отже, обрані методики ДФУ 2.0 цілком придатні для визначення кількісного вмісту поліфенолів, танінів та суми гідроксикоричних і органічних кислот у серіях плодів калини звичайної, що може бути використано в подальших роботах зі стандартизації сировини

Bulk Scalar Stabilization of the Radion without Metric Back-Reaction in the Randall-Sundrum Model

Generalizations of the Randall-Sundrum model containing a bulk scalar field $\Phi$ interacting with the curvature $R$ through the general coupling $R f(\Phi)$ are considered. We derive the general form of the effective 4D potential for the spin-zero fields and show that in the mass matrix the radion mixes with the Kaluza-Klein modes of the bulk scalar fluctuations. We demonstrate that it is possible to choose a non-trivial background form $\Phi_0(y)$ (where $y$ is the extra dimension coordinate) for the bulk scalar field such that the exact Randall-Sundrum metric is preserved (i.e. such that there is no back-reaction). We compute the mass matrix for the radion and the KK modes of the excitations of the bulk scalar relative to the background configuration $\Phi_0(y)$ and find that the resulting mass matrix implies a non-zero value for the mass of the radion (identified as the state with the lowest eigenvalue of the scalar mass matrix). We find that this mass is suppressed relative to the Planck scale by the standard warp factor needed to explain the hierarchy puzzle, implying that a mass \sim 1\tev is a natural order of magnitude for the radion mass. The general considerations are illustrated in the case of a model containing an $R\Phi^2$ interaction term.Comment: 22 pages, 3 figure

High-dose-rate Interstitial Brachytherapy Boost with a Pedicled Latissimus Dorsi Myocutaneous Flap for Myxofibrosarcoma of the Arm

Summary: A 71-year-old man was found to have a 7.4 × 2.9 × 7.0 cm myxofibrosarcoma of the right medial arm close to neurovascular structures. He received 50 Gray (Gy) of preoperative external beam radiation. Radical resection resulted in a 15 × 10 cm defect. Nine brachytherapy catheters were placed, and a pedicled latissimus dorsi myocutaneous flap was used in reconstruction. Final pathology confirmed myxofibrosarcoma, high grade. The tumor was <1 mm from 2 margins. A total of 17.5 Gy of brachytherapy was delivered to the surgical bed from postoperative days 7 to 9. The flap developed fat necrosis distally which eventually required surgical debridement on postoperative day 58. It subsequently healed well and maintained good function of the limb. The patient remains under surveillance without evidence of recurrence

Astronomy with Small Telescopes

The All Sky Automated Survey (ASAS) is monitoring all sky to about 14 mag with a cadence of about 1 day; it has discovered about 10^5 variable stars, most of them new. The instrument used for the survey had aperture of 7 cm. A search for planetary transits has lead to the discovery of about a dozen confirmed planets, so called 'hot Jupiters', providing the information of planetary masses and radii. Most discoveries were done with telescopes with aperture of 10 cm. We propose a search for optical transients covering all sky with a cadence of 10 - 30 minutes and the limit of 12 - 14 mag, with an instant verification of all candidate events. The search will be made with a large number of 10 cm instruments, and the verification will be done with 30 cm instruments. We also propose a system to be located at the L_1 point of the Earth - Sun system to detect 'killer asteroids'. With a limiting magnitude of about 18 mag it could detect 10 m boulders several hours prior to their impact, provide warning against Tunguska-like events, as well as to provide news about spectacular but harmless more modest impacts.Comment: 11 pages, accepted to PASP minor changes to the tex