107 research outputs found
Wright meets Markowitz: How standard portfolio theory changes when assets are technologies following experience curves
Get PDFWe consider how to optimally allocate investments in a portfolio of competing technologies using the standard mean-variance framework of portfolio theory. We assume that technologies follow the empirically observed relationship known as Wright's law, also called a “learning curve” or “experience curve”, which postulates that costs drop as cumulative production increases. This introduces a positive feedback between cost and investment that complicates the portfolio problem, leading to multiple local optima, and causing a trade-off between concentrating investments in one project to spur rapid progress vs. diversifying over many projects to hedge against failure. We study the two-technology case and characterize the optimal diversification in terms of progress rates, variability, initial costs, initial experience, risk aversion, discount rate and total demand. The efficient frontier framework is used to visualize technology portfolios and show how feedback results in nonlinear distortions of the feasible set. For the two-period case, in which learning and uncertainty interact with discounting, we compare different scenarios and find that the discount rate plays a critical role
Nonparametric Tests for Serial Independence Based on Quadratic Forms
Get PDFTests for serial independence and goodness-of-fit based on divergence notions between probability distributions, such as the Kullback-Leibler divergence or Hellinger distance, have recently received much interest in time series analysis. The aim of this paper is to introduce tests for serial independence using kernel-based quadratic forms. This separates the problem of consistently estimating the divergence measure from that of consistently estimating the underlying joint densities, the existence of which is no longer required. Exact level tests are obtained by implementing a Monte Carlo procedure using permutations of the original observations. The bandwidth selection problem is addressed by introducing a multiple bandwidth procedure based on a range of different bandwidth values. After numerically establishing that the tests perform well compared to existing nonparametric tests, applications to estimated time series residuals are considered. The approach is illustrated with an application to financial returns data.
Conceptualization of the phenomenon of ecological values as a basic notion for professional training of future natural sciences teachers
Get PDFRohoza Valentyn. Conceptualization of the phenomenon of ecological values as a basic notion for professional training of future natural sciences teachers. Pedagogy and Psychology of Sport. 2019;5(1):108-120. elSSN 2450-6605. DOI http://dx.doi.org/10.12775/PPS.2019.05.01.002
http://apcz.umk.pl/czasopisma/index.php/PPS/article/view/PPS.2019.05.01.002
https://zenodo.org/record/4281658
The journal has had 5 points in Ministry of Science and Higher Education parametric evaluation. § 8. 2) and § 12. 1. 2) 22.02.2019.
© The Authors 2019;
This article is published with open access at Licensee Open Journal Systems of Nicolaus Copernicus University in Torun, Poland
Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author (s) and source are credited. This is an open access article licensed under the terms of the Creative Commons Attribution Non commercial license Share alike.
(http://creativecommons.org/licenses/by-nc-sa/4.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited.
The authors declare that there is no conflict of interests regarding the publication of this paper.
Received: 01.06.2019. Revised: 14.06.2019. Accepted: 24.06.2019.
CONCEPTUALIZATION OF THE PHENOMENON OF ECOLOGICAL VALUES AS A BASIC NOTION FOR PROFESSIONAL TRAINING OF FUTURE NATURAL SCIENCES TEACHERS
Valentyn Rohoza
Research fellow of the Department of Profile Education of the
Institute of Pedagogy of the National Academy of
Pedagogical Sciences of Ukraine
e-mail: [email protected]
ORCID ID: 0000-0002-9552-0310
Abstract
The article conceptualizes the phenomenon of “ecological values”, which is the basis of educational and professional training of future teachers of natural sciences. The research focuses on identifying the system of values and their hierarchy in order to achieve at least two key results: 1) the formation of a higher level of a value sphere of future natural sciences teachers and improvement of the process of acquired values transfer; 2) improvement of learning outcomes (improvement in behavior, awareness, knowledge). Based on the extensive analysis of the scientific literature, the research suggests the meaningful characteristic of the formulated ecological values of the future natural sciences teachers. As a result, the research has considered the ecological values of future natural sciences teachers as an integrated value block in the system of their value orientations.
Key words: values, ecological values, future teachers, concept, professional training
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Measuring costs of carbon sequestration in northwest Russia
Get PDFGlobal warming that may cause environmental catastrophes, dramatic economic losses and, in extreme case, may lead to an extinction of human race, is driven by anthropogenic emissions of greenhouse gases (carbon dioxide, methane, nitrous oxide and others) into atmosphere. It has been shown that forests can efficiently absorb carbon from the atmosphere and reduce the concentration of greenhouse gases mitigating climatic change. In this study we explore environmentally oriented forest management options for carbon mitigation. We concentrate on Northwest Russia, St. Petersburg region in particular. This research is a part of larger project comparing carbon dynamics in two ecosystems: U.S. Pacific Northwest and Northwest Russia. We use STANIDCARB model to simulate the growth of forest and account for sequestered carbon that allow exploring the effect of different management regimes on carbon storage and economic value. We evaluate 140 regimes with different combinations of rotation length, regeneration type, intensity and frequency of thinnings. We employ Data Envelopment Analysis to identify the set of carbon and profit efficient management regimes. The set of efficient points comprises production possibility frontier that shows a tradeoff between stored carbon and monetary value. Then, we measure the marginal costs of carbon sequestration along the production possibility frontier. The results suggested that the marginal costs of carbon sequestration exhibit diminishing returns and are negatively correlated with the discount rate. At 4% discount rate the marginal costs vary from 0.08 to 4.71 USD
Author Correction: Structural basis for translational control by the human 48S initiation complex
No full textComplications of epidural adhesiolysis
Get PDFFishchenko Iakiv, Piontkovskyi Valentyn, Zlativ Volodimir. Complications of epidural adhesiolysis. Journal of Education, Health and Sport. 2016;6(2):183-189. eISSN 2391-8306. DOI http://dx.doi.org/10.5281/zenodo.46408
http://ojs.ukw.edu.pl/index.php/johs/article/view/3384
https://pbn.nauka.gov.pl/works/716072
The journal has had 7 points in Ministry of Science and Higher Education parametric evaluation. Part B item 755 (23.12.2015).
755 Journal of Education, Health and Sport eISSN 2391-8306 7
© The Author (s) 2016;
This article is published with open access at Licensee Open Journal Systems of Kazimierz Wielki University in Bydgoszcz, Poland
Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium,
provided the original author(s) and source are credited. This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License
(http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited.
This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted, non commercial
use, distribution and reproduction in any medium, provided the work is properly cited.
The authors declare that there is no conflict of interests regarding the publication of this paper.
Received: 05.01.2016. Revised 12.02.2016. Accepted: 21.02.2016.
Complications of epidural adhesiolysis
Iakiv Fishchenko
SI "Institute of traumatology and orthopedics NAMS of Ukraine"
Valentyn Piontkovskyi
Rivne rigional hospital Ukraine
Volodimir Zlativ
Rivne rigional hospital, Ukraine
Complications of epidural adhesiolysis
Epidural adhesiolysis is a minimally invasive procedure used to treat neuro-compression pain of the lumbosacral part of spine with degenerative diseases. Thanks to being minimally invasive and to its high efficiency, the rate of this procedure in recent years has increased significantly. On a material of 760 patients we analyzed the mistakes and complications related to epidural adhesiolysis. The complications of varying severity were observed in our 297 (30.0%) patients. Of these, the complications which did not require any modifications of treatment strategies, or its minor correction occurred in 277 (36.4%) patients; complications requiring reinstallation of the catheter were observed in 15 (1.9%) patients; complications of moderate severity, as epidural hematoma, epiduritis we noted in 5 (0.6%) patients; threatening complication of spontaneous rupture of the dura mater followed by the catheter hypertonic solution of sodium chloride, we observed in one (0.1%) case.
Key words: epidural adhesiolysis, neuro-compression pain, complications
Asset prices, traders' behavior and market design
No full textThe dynamics of a financial market with heterogeneous agents are analyzed under different market architectures. We start with a tractable behavioral model under Walrasian market clearing and simulate it under different trading protocols. The key behavioral feature of the model is the switching by agents between simple forecasting rules on the basis of a fitness measure. By analyzing the dynamics under order-driven protocols we show that the behavioral and structural assumptions of the model are closely intertwined. The high responsiveness of agents to a fitness measure causes excess volatility, but the frictions of the order-driven markets may stabilize the dynamics. We also analyze and compare allocative efficiency and time series properties under different protocols.Asset pricing model Heterogeneous beliefs Learning Trading protocols Market architecture
Efficient estimation of parameters in marginals in semiparametric multivariate models∗
No full textRecent literature on semiparametric copula models focused on the situation when the marginals are specified nonparametrically and the copula function is given a parametric form. For example, this setup is used in Chen, Fan and Tsyrennikov (2006) [Efficient Estimation of Semiparametric Multivariate Copula Models, JASA] who focus on efficient estimation of copula parameters. We consider a reverse situation when the marginals are specified parametrically and the copula function is modelled nonparametrically. This setting is no less relevant in applications. We use the method of sieve for efficient estimation of parameters in marginals, derive its asymptotic distribution and show that the estimator is semiparametrically efficient. Simulations suggest that the sieve MLE can be up to 70 % more efficient relative to QMLE depending on the strength of dependence between the marginals. An application using insurance company loss and expense data demonstrates empirical relevance of this setting. JEL Classification: C1
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