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1
CHETOUANI, YAHYA. "USE OF CUMULATIVE SUM (CUSUM) TEST FOR DETECTING ABRUPT CHANGES IN THE PROCESS DYNAMICS." International Journal of Reliability, Quality and Safety Engineering 14, no. 01 (February 2007): 65–80. http://dx.doi.org/10.1142/s0218539307002519.
Анотація:
In order to operate a successful plant or process, continuous improvement must be made in the areas of safety, quality and reliability. Central to this continuous improvement is the early or proactive detection of process faults. Even though fault detection algorithms are designed and implemented for quickly detecting incidents, most these algorithms do not have an optimal property in terms of detection delay with respect to false alarm rate. Based on this optimization property, a real-time system for detecting changes in dynamic systems is designed in this paper. This work is motivated by combining two fault detection (FD) methods; a simplified procedure of the incident detection problem is formulated by using the combination of the Artificial Neural Networks (ANN) and the cumulative sum (CUSUM) or Page-Hinkley test. It is intended to reveal any drift from the normal behavior of the process. The process behavior under its normal operating conditions is established by a reliable model. In order to obtain this reliable model for the process dynamics, the black-box identification by means of a NARX (Nonlinear Auto-Regressive with eXogenous input) model is chosen in this study. The purpose is to develop and test the fault detection method on a real incident data, to detect the change presence, and pinpoint the moment it occurred. The experimental results demonstrate the robustness of the FD method.
2
Nasirzadeh, Farnad, Abbas Afshar, and Mostafa Khanzadi. "Dynamic risk analysis in construction projects." Canadian Journal of Civil Engineering 35, no. 8 (August 2008): 820–31. http://dx.doi.org/10.1139/l08-035.
Анотація:
The occurrence of one risk may exacerbate other risks or portfolios of risks due to their highly complex interrelated structures and existing interactions. Hence, the cumulative impact of a chain of risks may be greater than the sum of their individual impacts. Commonly practiced risk analysis approaches do not account for these interactions and face deficiency in providing reliable information regarding the actual impact of the identified risks. This paper presents a new approach to construction risk analysis where the interrelated structure of risks and their interactions have been modeled through the governing feedback loops. The proposed methodology is a system dynamics-based approach for risk analysis and assessment. The full impact of a risk or a set of risks may efficiently be modeled, simulated, and quantified in terms of time and cost by the proposed object-oriented simulation methodology. To evaluate the performance of the proposed methodology, it has been incorporated into a bridge construction project. The interrelated structures of the identified risks have been modeled and their cumulative consequences simulated and quantified as an illustrative example.
3
Cvitanić, Jakša, and George Georgiadis. "Achieving Efficiency in Dynamic Contribution Games." American Economic Journal: Microeconomics 8, no. 4 (November 1, 2016): 309–42. http://dx.doi.org/10.1257/mic.20160018.
Анотація:
We analyze a game in which a group of agents exerts costly effort over time to make progress on a project. The project is completed once the cumulative effort reaches a prespecified threshold, at which point it generates a lump-sum payoff. We characterize a budget-balanced mechanism that induces each agent to exert the first-best effort level as the outcome of a Markov perfect equilibrium, thus eliminating the free-rider problem. We also show how our mechanism can be adapted to other dynamic games with externalities, such as strategic experimentation and the dynamic extraction of a common resource. (JEL C73, D62, D82, Q31)
4
Yang, Jiangbin, and Viliam Makis. "Dynamic Response of Residuals of a Controlled Cutting Process to Shifts in the Process Mean." International Journal of Reliability, Quality and Safety Engineering 05, no. 02 (June 1998): 157–68. http://dx.doi.org/10.1142/s0218539398000169.
Анотація:
A usual approach to monitoring an autocorrelated process is to apply a control chart to the process residuals. In this paper, we study the statistical behavior of the residuals of a controlled second-order autoregressive (AR(2)) cutting process when a special-cause shift occurs to the process mean. Shewhart, exponentially weighted moving average (EWMA) and cumulative sum (CUSUM) control charts are applied to the residuals to monitor the cutting process. Formulas, integral equations and recursive procedures for computing the average run lengths (ARLs) of the charts are derived. Numerical results are presented and the relative performance of the charts is investigated.
5
TIAN, LIANG, and AFZEL NOORE. "SOFTWARE RELIABILITY PREDICTION USING RECURRENT NEURAL NETWORK WITH BAYESIAN REGULARIZATION." International Journal of Neural Systems 14, no. 03 (June 2004): 165–74. http://dx.doi.org/10.1142/s0129065704001966.
Анотація:
A recurrent neural network modeling approach for software reliability prediction with respect to cumulative failure time is proposed. Our proposed network structure has the capability of learning and recognizing the inherent internal temporal property of cumulative failure time sequence. Further, by adding a penalty term of sum of network connection weights, Bayesian regularization is applied to our network training scheme to improve the generalization capability and lower the susceptibility of overfitting. The performance of our proposed approach has been tested using four real-time control and flight dynamic application data sets. Numerical results show that our proposed approach is robust across different software projects, and has a better performance with respect to both goodness-of-fit and next-step-predictability compared to existing neural network models for failure time prediction.
6
Upadhyay, Hari Prasad, Bijay Lal Pradhan, Omkar Poudel, Keshab Raj Sapkota, and Daya Ram Simkhada. "Impact of Remittance, Money Supply and Inflation on Economic Growth of Nepal: Using Autoregressive Distributed Lag Model (ARDL)." BMC Journal of Scientific Research 5, no. 1 (December 31, 2022): 52–59. http://dx.doi.org/10.3126/bmcjsr.v5i1.50673.
Анотація:
Remittances have become a major source of funding in developing countries. A time series analysis was conducted by taking the 25 years data of economic growth as a dependent variable while remittance, money supply and Inflation as independent variables form the annual report of Economic survey of Nepal (2020/21). The autoregressive distributive lag (ARDL) was used to study the relationship among the variables. The trend of economic growth and total percentage of economic growth is in increasing order. The relation between then was found as LN(Economic Growth) =8.0740 +0.220*LNREM + 0.3123 *LNM2-0.0802*LNINF. The stability test of long-run coefficient including short run was studied using ARDL model and are confirmed using Cumulative Sum chart (CUSUM) and cumulative sum of squares test (CUSUMSQ) test. Finding shows that there is long run positive relationship between remittance, money supply, inflation on economic growth of Nepal. From the analysis it is clear that coefficients of error correction are highly significant this indicate that adjustment to longterm equilibrium in the dynamic model and ARDL model showed all the independent variables had positive impact on economic growth of Nepal.
7
Jiao, Yubo, Yao Zhang, Wenchen Shan, Qiang Han, Yunpeng Zhao, and Shiqi Liu. "Damage fracture characterization of reinforced concrete beam subjected to four-point bending with parametric analysis of static, dynamic, and acoustic properties." Structural Health Monitoring 19, no. 4 (October 17, 2019): 1202–18. http://dx.doi.org/10.1177/1475921719881756.
Анотація:
The aim of this study is to clarify the damage fracture process using acoustic emission technique and construct relationships between acoustic emission parameters and static, dynamic properties of reinforced concrete beam under four-point bending. Laboratory experiments were performed on two reinforced concrete beams with same length 250 cm. Static parameters including crack and displacement patterns with load level were observed and analyzed. Acoustic emission parameters of hit, count, amplitude, energy, duration, index of damage, and b-value with the increase in damage were demonstrated and corresponded to observed crack status of structure, which realized the damage process classification and mechanism characterization. Correlations of acoustic emission parameters and cumulative crack width with the first-order natural frequency were obtained to clarify their relevance. The results revealed that as the level of damage increased, the values of cumulative acoustic emission parameters increased, which could classify the damage fracture process into four stages. And the results coincided with the observed crack and displacement patterns of reinforced concrete beam. Sum of maximum width for observed cracks presented favorable quadric relations with acoustic emission parameters. Index of damage and b-value analyses (classical and Gaussian filtered ones) demonstrated the crack characteristic at each load step, which were in accordance with the observed crack patterns. Change rate of the first-order natural frequency presented favorable cubic relationships with acoustic emission energy and hit, while linear and negative relations with sum of crack widths. The results obtained in this study can be used for damage fracture characterization and health monitoring of reinforced concrete structures subjected to flexural load.
8
Saleem, Shaikh Muhammad, Muhammad Asif Shamim, Sayma Zia, and Syed Waqar-ul-Hassan. "AGRICULTURE EXPORT STIMULANT TO THE ECONOMIC AND FINANCIAL PERFORMANCE OF PAK." Humanities & Social Sciences Reviews 9, no. 2 (April 29, 2021): 572–80. http://dx.doi.org/10.18510/hssr.2021.9253.
Анотація:
Purpose: The study examines how agricultural exports boost the economic growth of Pakistan in the long run and suggest policy implications during 1995-2018 using time series data.
Methodology: Principal Component Analysis is used to construct an agricultural export index consisting of rice, raw cotton, fruits, and vegetables as variables. This quantitative study checked the structural stability of the model with cumulative-sum & cumulative-sum of the square. Rolling window analysis highlights the long-run yearly effect of the coefficient of the model. The result of variance decomposition method proof bidirectional causality where robust result proof using Fully modified ordinary least square and Dynamic ordinary least square techniques. Unit root at first difference proof stationery whereas cointegration has a long-run relationship between agricultural export and economic growth.
Main Finding: The statistical estimation proofs the positive long-run association of agricultural exports with economic growth. Results explored a 26 percent increase in the economy of Pakistan by exporting agricultural goods.
Application of this Study: This study helps to develop the economies if they face problems of low agricultural productivity. The agricultural export is sensitive to domestic indicators, and domestic policy can promote agricultural export, and create new potential markets.
The originality of the Study: The study is suggested the agriculture techniques and their performance in developing economies.
9
Pakyürek, Muhammet, Osman Dikmen, and Selman Kulaç. "Exponentially-Weighted Based Dynamic Pilot Power Allocation in Massive MIMO Systems." Traitement du Signal 39, no. 2 (April 30, 2022): 627–31. http://dx.doi.org/10.18280/ts.390225.
Анотація:
In this paper, we propose a distinctive pilot power allocation algorithm to maximize the sum rate in a multi-cell multi-user massive multiple-input multiple-output (MIMO) system. The algorithm optimizes pilot powers by polarizing the corresponding SINR values. In order to polarize SINRs, the difference between average SINR per cell and individual SINR is calculated for each user of the whole cells. The exponential form of the difference is used in the calculations of the weights for power allocation. New power values are obtained in proportion to these weights. Therefore, the power budget is utilized more efficiently thanks to these optimized power values. The efficiency of the algorithm is measured using the cumulative average SINR of the simulation system. Furthermore, equal pilot power allocation (EPPA) and water-filling pilot power allocation (WF-PPA) schemes are also implemented to compare the performances under the same simulation environments. A vast number of simulations results prove that our proposed heuristic approach is more efficient than EPPA and WF-PPA methods.
10
Bonin, J. A., and D. P. Chambers. "Quantifying the resolution level where the GRACE satellites can separate Greenland's glacial mass balance from surface mass balance." Cryosphere 9, no. 5 (September 4, 2015): 1761–72. http://dx.doi.org/10.5194/tc-9-1761-2015.
Анотація:
Abstract. Mass change over Greenland can be caused by either changes in the glacial dynamic mass balance (DMB) or the surface mass balance (SMB). The GRACE satellite gravity mission cannot directly separate the two physical causes because it measures the sum of the entire mass column with limited spatial resolution. We demonstrate one theoretical way to indirectly separate cumulative SMB from DMB with GRACE, using a least squares inversion technique with knowledge of the location of the glaciers. However, we find that the limited 60 × 60 spherical harmonic representation of current GRACE data does not provide sufficient resolution to adequately accomplish the task. We determine that at a maximum degree/order of 90 × 90 or above, a noise-free gravity measurement could theoretically separate the SMB from DMB signals. However, current GRACE satellite errors are too large at present to separate the signals. A noise reduction of a factor of 10 at a resolution of 90 × 90 would provide the accuracy needed for the interannual cumulative SMB and DMB to be accurately separated.
11
Liu, Xixiang, Jian Sima, Yongjiang Huang, Xianjun Liu, and Pan Zhang. "A Simplified Kalman Filter for Integrated Navigation System with Low-Dynamic Movement." Mathematical Problems in Engineering 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/3528146.
Анотація:
In the integrated navigation system with inertial base, the update frequency of Strapdown Inertial Navigation System (SINS) is always higher than those of aided navigation systems; thus updating inconsistency among subsystems becomes an issue. The analysis indicates that the state transition matrix in Kalman filter is essentially a function of carrier motion. Based on this understanding, a simplified Kalman filter algorithm for integrated navigation is designed for those carriers with low-dynamic motions. With this simplified algorithm, when the filter is without aided information updating, only calculation and accumulation on state transition matrix are executed, and when the filter is with updating, normal time and measurement update are done based on the averaged state transition matrix. Thus the calculation load in the simplified algorithm will be significantly lessened. Furthermore, due to cumulative sum and average operation, more accurate state transition matrix and higher fusion accuracy will arrive for the smoothing effect on random noise of carrier motion parameters. Simulation and test results indicate that when the carrier is with a low-dynamic motion, the simplified algorithm can complete the data fusion of integrated system effectively with reduced computation load and suppressed oscillation amplitude of state vector error.
12
Ash, Eric, Samuel A. Cushman, David W. Macdonald, Tim Redford, and Żaneta Kaszta. "How Important Are Resistance, Dispersal Ability, Population Density and Mortality in Temporally Dynamic Simulations of Population Connectivity? A Case Study of Tigers in Southeast Asia." Land 9, no. 11 (October 28, 2020): 415. http://dx.doi.org/10.3390/land9110415.
Анотація:
Development of landscape connectivity and spatial population models is challenging, given the uncertainty of parameters and the sensitivity of models to factors and their interactions over time. Using spatially and temporally explicit simulations, we evaluate the sensitivity of population distribution, abundance and connectivity of tigers in Southeast Asia to variations of resistance surface, dispersal ability, population density and mortality. Utilizing a temporally dynamic cumulative resistant kernel approach, we tested (1) effects and interactions of parameters on predicted population size, distribution and connectivity, and (2) displacement and divergence in scenarios across timesteps. We evaluated the effect of varying levels of factors on simulated population, cumulative resistance kernel extent, and kernel sum across nine timesteps, producing 24,300 simulations. We demonstrate that predicted population, range shifts, and landscape connectivity are highly sensitive to parameter values with significant interactions and relative strength of effects varying by timestep. Dispersal ability, mortality risk and their interaction dominated predictions. Further, population density had intermediate effects, landscape resistance had relatively low impacts, and mitigation of linear barriers (highways) via lowered resistance had little relative effect. Results are relevant to regional, long-term tiger population management, providing insight into potential population growth and range expansion across a landscape of global conservation priority.
13
Wang, Di, and Xi Zhang. "Dynamic Field Monitoring Based on Multitask Learning in Sensor Networks." Sensors 19, no. 7 (March 29, 2019): 1533. http://dx.doi.org/10.3390/s19071533.
Анотація:
Field monitoring serves as an important supervision tool in a variety of engineering domains. An efficient monitoring would trigger an alarm timely once it detects an out-of-control event by learning the state change from the collected sensor data. However, in practice, multiple sensor data may not be gathered appropriately into a database for some unexpected reasons, such as sensor aging, wireless communication failures, and data reading errors, which leads to a large number of missing data as well as inaccurate or delayed detection, and poses a great challenge for field monitoring in sensor networks. This fact motivates us to develop a multitask-learning based field monitoring method in order to achieve an efficient detection when considerable missing data exist during data acquisition. Specifically, we adopt a log likelihood ratio (LR)-based multivariate cumulative sum (MCUSUM) control chart given spatial correlation among neighboring regions within the monitored field. To deal with the missing data problem, we integrate a multitask learning model into the LR-based MCUSUM control chart in the sensor network. Both simulation and real case studies are conducted to validate our proposed approach and the results show that our approach can achieve an accurate and timely detection for an out-of-control state when a large number of missing data exist in the sensor database. Our model provides an effective field monitoring strategy for engineering applications to accurately and timely detect the products with abnormal quality during production and reduce product losses.
14
Sakib, Arfanul Ibna Mustafa. "Is Okun’s Law Valid in Bangladesh? A Time Series Analysis." South Asia Economic Journal 24, no. 2 (September 2023): 137–52. http://dx.doi.org/10.1177/13915614231198283.
Анотація:
Using the data from 1991 to 2019, this study attempts to verify Okun’s law by utilizing both ‘The difference and the dynamic versions’ of Okun’s law in Bangladesh and tries to find the value of Okun’s coefficient. The autoregressive-distribution lag (ARDL) bounds test is applied to determine the existence of a long-term relationship between the variables, and then the ordinary least squares (OLS) approach is used to estimate the findings. The findings show that Okun’s coefficient is –0.058 for the difference version of Okun’s law, which is statistically insignificant. In addition, for the dynamic version of Okun’s law, findings show that the effect of the ‘immediate past economic growth rate’ on ‘current change in the unemployment rate’ is 0.15, and it is statistically insignificant too. However, the effect of the ‘current economic growth rate’ on ‘current change in the unemployment rate’ is –0.22, and it is statistically significant at 10% significance level. In both versions of Okun’s law, R2 values, F-statistic and cumulative sum of squares show the instability of the models. Due to statistically insignificant coefficients and model instability, it can be concluded that Okun’s law is invalid in Bangladesh. JEL Codes: E24, C22, B23, C87
15
Choi, Chang-Ho Ryan, Ibrahim Al Bakir, Nik-Sheng (John) Ding, Gui-Han Lee, Alan Askari, Janindra Warusavitarne, Morgan Moorghen, et al. "Cumulative burden of inflammation predicts colorectal neoplasia risk in ulcerative colitis: a large single-centre study." Gut 68, no. 3 (November 17, 2017): 414–22. http://dx.doi.org/10.1136/gutjnl-2017-314190.
Анотація:
ObjectiveUlcerative colitis (UC) is a dynamic disease with its severity continuously changing over time. We hypothesised that the risk of colorectal neoplasia (CRN) in UC closely follows an actuarial accumulative inflammatory burden, which is inadequately represented by current risk stratification strategies.DesignThis was a retrospective single-centre study. Patients with extensive UC who were under colonoscopic surveillance between 2003 and 2012 were studied. Each surveillance episode was scored for a severity of microscopic inflammation (0=no activity; 1=mild; 2=moderate; 3=severe activity). The cumulative inflammatory burden (CIB) was defined as sum of: average score between each pair of surveillance episodes multiplied by the surveillance interval in years. Potential predictors were correlated with CRN outcome using time-dependent Cox regression.ResultsA total of 987 patients were followed for a median of 13 years (IQR, 9-18), 97 (9.8%) of whom developed CRN. Multivariate analysis showed that the CIB was significantly associated with CRN development (HR, 2.1 per 10-unit increase in CIB (equivalent of 10, 5 or 3.3 years of continuous mild, moderate or severe active microscopic inflammation); 95% CI 1.4 to 3.0; P<0.001). Reflecting this, while inflammation severity based on the most recent colonoscopy alone was not significant (HR, 0.9 per-1-unit increase in severity; 95% CI 0.7 to 1.2; P=0.5), a mean severity score calculated from all colonoscopies performed in preceding 5 years was significantly associated with CRN risk (HR, 2.2 per-1-unit increase; 95% CI 1.6 to 3.1; P<0.001).ConclusionThe risk of CRN in UC is significantly associated with accumulative inflammatory burden. An accurate CRN risk stratification should involve assessment of multiple surveillance episodes to take this into account.
16
Al-Shayeb, Abdulrahman, and Abdulnasser Hatemi-J. "Trade openness and economic development in the UAE: an asymmetric approach." Journal of Economic Studies 43, no. 4 (September 12, 2016): 587–97. http://dx.doi.org/10.1108/jes-06-2015-0094.
Анотація:
Purpose The purpose of this paper is to offer a review of the trade policy in the UAE. It also investigates the dynamic interaction between trade openness and GDP per capita in this emerging economy. Design/methodology/approach The asymmetric generalized impulse response functions and the asymmetric causality tests developed by Hatemi-J are used. Findings The results from asymmetric generalized impulse response functions indicate that a positive permanent shock in the trade openness results in a significant positive response in the cumulative sum of the positive component of the GDP per capita. Such a response is not found for the negative shocks in the trade openness. Furthermore, neither a positive nor a negative shock in the GPD per capita results in any significant response in the trade openness. These empirical findings are also supported by the implemented asymmetric causality tests. Originality/value This is the first attempt that investigates the impact of trade openness on economic performance in the UAE. Unlike previous literature on the topic, this paper allows for asymmetric impacts in the empirical model.
17
Yi, Ting-Hua, Hong-Nan Li, Gangbing Song, and Qing Guo. "Detection of Shifts in GPS Measurements for a Long-Span Bridge Using CUSUM Chart." International Journal of Structural Stability and Dynamics 16, no. 04 (March 28, 2016): 1640024. http://dx.doi.org/10.1142/s0219455416400241.
Анотація:
Timely and correctly evaluating the quality of Global Positioning System (GPS) data is essential for reduction in the number of false alarms and missed detection of a GPS-based bridge deformation monitoring system. This paper investigates how to use the statistical process control technique, known as the cumulative sum (CUSUM) chart, for the detection of small but persistent shifts in the high-rate GPS carrier-phase measurements. First, a mathematical model for the shift detection based on the continuous hypothesis testing is established. The main features and implementation procedure of the CUSUM chart for the shift detection are then summarized, and the corresponding parameter selection method is discussed in detail. To meet the normality requirement of the CUSUM chart, a novel method that transfers the data to the Q-statistic by the estimated cumulative distribution functions is proposed according to the probability integral transform theory. This is followed by a simulation carried out to evaluate the detection performance of the CUSUM chart and exploit its advantages to the commonly used Shewhart chart for the high-rate GPS monitoring data with different shift sizes. Experimental results have showed that the CUSUM chart is sensitive to small persistent shifts compared to the Shewhart chart although it has a delay problem. The integration of CUSUM chart and Shewhart chart would be a reliable approach for the shift detection. Finally, an on-site dynamic monitoring experiment is carried out on a long-span bridge to validate the proposed approach’s effectiveness in detecting an actual deformation shift, and the experimental results proved to be very encouraging.
18
Li, Hongqiao, Xiongyao Xie, Yonglai Zhang, and Qiang Wang. "Theoretical, Numerical, and Experimental Study on the Identification of Subway Tunnel Structural Damage Based on the Moving Train Dynamic Response." Sensors 21, no. 21 (October 29, 2021): 7197. http://dx.doi.org/10.3390/s21217197.
Анотація:
As an important part of urban rail transit, subway tunnels play an important role in alleviating traffic pressure in mega-cities. Identifying and locating damage to the tunnel structure as early as possible has important practical significance for maintaining the long-term safe operation of subway tunnels. Summarizing the current status and shortcomings of the structural health monitoring of subway tunnels, a very economical and effective monitoring program is proposed, which is to use the train vibration response to identify and locate the damage of the tunnel structure. Firstly, the control equation of vehicle–tunnel coupling vibration is established and its analytical solution is given as the theoretical basis of this paper. Then, a damage index based on the cumulative sum of wavelet packet energy change rate (TDISC) is proposed, and its process algorithm is given. Through the joint simulation of VI-Rail and ANSYS, a refined 3D train-tunnel coupled vibration model is established. In this model, different combined conditions of single damage and double damage verify the validity of the damage index. The effectiveness of this damage index was further verified through model tests, and the influence of vehicle speed and load on the algorithm was discussed. Numerical simulation and experimental results show that the TDISC can effectively locate the damage of the tunnel structure and has good robustness.
19
Bărbuță-Mișu, Nicoleta, Tuna Can Güleç, Selim Duramaz, and Florina Oana Virlanuta. "Determinants of Dollarization of Savings in the Turkish Economy." Sustainability 12, no. 15 (July 30, 2020): 6141. http://dx.doi.org/10.3390/su12156141.
Анотація:
This study aims to analyze the nature of the dollarization that takes place in the Turkish economy and to decompose the factors that have contributed to its increase in recent years. With this purpose, we first identify the events that have significantly affected the dollarization trend in Turkey using the Iterative Cumulative Sum of Squares (ICSS) and Markov Switching Dynamic Regression (MS-Dynamic) structural break models. Then, we proceed to analyze the relationship between the percentage of Forex deposits of the residents over total deposits of the residents and the TRY/USD exchange rate using the Johansen cointegration test. USD, EUR, and TRY interest rates are also added to the model as independent variables to account for the effects of the difference between exchange rates. Long-term and short-term effects are tested with the Vector Error Correction Model, and causality is tested using the Granger causality test. The results of the study indicate that speculative trading is not the cause of the dollarization of deposits in Turkey. Additionally, results suggest that the political events have a stronger influence over dollarization compared to economic events. Collectively, our findings suggest that domestic citizens dollarize their deposits with the motivation to protect against political ambiguity rather than economic volatility. The results of the study are in line with the literature in the sense that they support the claim that dollarization can be averted in the short run with an increase in interest rates.
20
Gunay, Samet, Walid Bakry, and Somar Al-Mohamad. "The Australian Stock Market’s Reaction to the First Wave of the COVID-19 Pandemic and Black Summer Bushfires: A Sectoral Analysis." Journal of Risk and Financial Management 14, no. 4 (April 11, 2021): 175. http://dx.doi.org/10.3390/jrfm14040175.
Анотація:
In this study, we investigated the impact of the first wave of the COVID-19 pandemic on various sectors of the Australian stock market. Market capitalization and equally weighted indices were formed for eleven Australian sectors to examine the influence of the pandemic on them. First, we examined the financial contagion between the Chinese stock market and Australian sector indices through the dynamic conditional correlation fractionally integrated generalized autoregressive conditional heteroskedasticity (DCC-FIGARCH) model. We found high time-varying correlations between the Chinese stock market and most of the Australian sector indices, with the financial, health care, information technology, and utility sectors displaying a decrease in co-movements during the pandemic. The Modified Iterative Cumulative Sum of Squares (MICSS) analysis results indicated the presence of structural breaks in the volatilities of most of the sector indices around the end of February 2020, but consumer staples, industry, information technology and real estate indices did not display any break. Markov regime-switching regression analysis depicted that the pandemic has mainly affected three sectors: consumer staples, industry, and real estate. When we considered the firm size, we found that smaller companies in the energy sector exhibited gradual deterioration, whereas small firms in the consumer staples sector experienced the largest positive impact from the pandemic.
21
Fallais, Dominik Johannes Marius, Maximilian Henkel, Nymfa Noppe, Wout Weijtjens, and Christof Devriendt. "Multilevel RTN Removal Tools for Dynamic FBG Strain Measurements Corrupted by Peak-Splitting Artefacts." Sensors 22, no. 1 (December 23, 2021): 92. http://dx.doi.org/10.3390/s22010092.
Анотація:
Strain measurements using fibre Bragg grating (FBG) optical sensors are becoming ever more commonplace. However, in some cases, these measurements can become corrupted by sudden jumps in the signal, which manifest as spikes or step-like offsets in the data. These jumps are caused by a defect in the FBG itself, which is referred to as peak-splitting. The effects of peak splitting artefacts on FBG strain measurements show similarities with an additive multi-level telegraph noise process, in which the amplitudes and occurrences of the jumps are related to fibre deformation states. Whenever it is not possible to re-assess the raw spectral data with advanced peak tracking software, other means for removing the jumps from the data have to be found. The two methods presented in this article are aimed at removing additive multi-level random telegraph noise (RTN) from the raw data. Both methods are based on denoising the sample wise difference signal using a combination of an outlier detection scheme followed by an outlier replacement step. Once the difference signal has been denoised, the cumulative sum is used to arrive back at a strain time series. Two methods will be demonstrated for reconstructing severely corrupted strain time series; the data for this verification has been collected from sub-soil strain measurements obtained from an operational offshore wind-turbine. The results show that the proposed methods can be used effectively to reconstruct the dynamic content of the corrupted strain time series. It has been illustrated that errors in the outlier replacements accumulate and can cause a quasi-static drift. A representative mean value and drift correction are proposed in terms of an optimization problem, which maximizes the overlap between the reconstruction and a subset of the raw data; whereas a high-pass filter is suggested to remove the quasi static drift if only the dynamic band of the signal is of interest.
22
Gasser, Thomas, Léa Crepin, Yann Quilcaille, Richard A. Houghton, Philippe Ciais, and Michael Obersteiner. "Historical CO<sub>2</sub> emissions from land use and land cover change and their uncertainty." Biogeosciences 17, no. 15 (August 13, 2020): 4075–101. http://dx.doi.org/10.5194/bg-17-4075-2020.
Анотація:
Abstract. Emissions from land use and land cover change are a key component of the global carbon cycle. However, models are required to disentangle these emissions from the land carbon sink, as only the sum of both can be physically observed. Their assessment within the yearly community-wide effort known as the “Global Carbon Budget” remains a major difficulty, because it combines two lines of evidence that are inherently inconsistent: bookkeeping models and dynamic global vegetation models. Here, we propose a unifying approach that relies on a bookkeeping model, which embeds processes and parameters calibrated on dynamic global vegetation models, and the use of an empirical constraint. We estimate that the global CO2 emissions from land use and land cover change were 1.36±0.42 PgC yr−1 (1σ range) on average over the 2009–2018 period and reached a cumulative total of 206±57 PgC over the 1750–2018 period. We also estimate that land cover change induced a global loss of additional sink capacity – that is, a foregone carbon removal, not part of the emissions – of 0.68±0.57 PgC yr−1 and 32±23 PgC over the same periods, respectively. Additionally, we provide a breakdown of our results' uncertainty, including aspects such as the land use and land cover change data sets used as input and the model's biogeochemical parameters. We find that the biogeochemical uncertainty dominates our global and regional estimates with the exception of tropical regions in which the input data dominates. Our analysis further identifies key sources of uncertainty and suggests ways to strengthen the robustness of future Global Carbon Budget estimates.
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Jancee, B. Victoria, and S. Radha. "Online Detection of Change on Information Streams in Wireless Sensor Network Modeled Using Gaussian Distribution." Modelling and Simulation in Engineering 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/658302.
Анотація:
Wireless sensor network (WSN) is deployed to monitor certain physical quantities in a region. This monitoring problem could be stated as the problem of detecting a change in the parameters of a static or dynamic stochastic system. A moving window procedure is proposed to detect the systematic error, which occurs at an unknown time. It can detect the deviation in the mean of sensor measurements keeping variance as constant. The performance measures, such as the average run length (ARL) to detection delay and false alarms are computed for various window sizes. The performance comparison is done against traditional cumulative sum (CUSUM) method. The detection of change in mean using CUSUM is done with smaller delay compared to the proposed moving window detection procedure. In order to calculate CUSUM statistics, the number of measurements to keep in sensor memory increases with time. However, in the proposed moving window detection procedure, the number of stored measurements is limited by the size of the window. Therefore, it is advantageous to use the moving window procedure for change detection in sensor nodes that have very limited memory. A high probability of detection is achieved at the cost of larger window size and higher detection delay. However, we are able to achieve the maximum probability of detection even at a window size of 11.
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Powęzka, Aleksandra, Mateusz Banaś, and Paweł Ogrodnik. "Checking the compatibility of embedded concrete for the production of prefabricated freight scales with the parameters declared by the supplier." MATEC Web of Conferences 247 (2018): 00015. http://dx.doi.org/10.1051/matecconf/201824700015.
Анотація:
The ready-mixed concrete is subject to certification in accordance with the compliance system 2+. Manufacturers of concrete are required to implement factory production control and then to certify concrete, which is subject to the national mark B. The paper presents the results of strength tests of C 40/50 concrete samples. Designed according to the 23M SCC recipe, concrete has been used in the production of freight scales. The samples were subjected to "in situ" tests. As a method of quality control, a non-destructive test method for concrete strength has been proposed. A sclerometer (Schmidt type N hammer) was used for the tests. The research used a dynamic method of measurement by evaluating the change in the energy of the beater after rebounding from a given surface. Normal cubes with dimensions 15x15x15 cm were used for the tests. Concrete testing was carried out after the 28th day of care in accordance with the requirements of PN-EN 2390-2:2001. Based on the analysis, conclusions from the tests were formulated. The compression strength class was determined and the conformity of the hardened concrete with the parameters declared by the manufacturer was controlled. The evaluation was carried out using methods B and C for continuous production. CUSUM cumulative sum control cards and Shewhart control cards were used.
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Sun, Jihong, Hui Li, Bo Zeng, Xiaoyun Zhao, and Chuanhui Wang. "Parameter Optimization on the Three-Parameter Whitenization Grey Model and Its Application in Simulation and Prediction of Gross Enrollment Rate of Higher Education in China." Complexity 2020 (December 19, 2020): 1–10. http://dx.doi.org/10.1155/2020/6640000.
Анотація:
The gray prediction model, based on the GM(1,1) method, is an important branch of gray theory with the most active research and the most fruitful results, and it is the most widely used because of its small sample size, simple modeling process, and easy to use. Such advantages have been successfully applied in many fields such as transportation, agriculture, energy, medicine, and environment and have been gradually developed into a mainstream predictive modeling method. This study combines the Three-parameter Whitenization Grey Model (TWGM(1,1)), which fits the inhomogeneous exponential law sequence, and the Particle Swarm Algorithm (PSA) to optimize the order and background value coefficients under the condition of the minimum sum of squares of simulation errors, and hence, to solve the problem that the cumulative order is fixed to “1” and the background value coefficient value is fixed to “0.5.” As a result, a parameter-optimized gray system model with flexibility, adaptability, and dynamic adjustment is designed to simulate and predict China’s higher education gross enrollment rate. The application shows that the model has better overall simulation and prediction performance than others. On the one hand, the parametric optimization model significantly improves its own performance, and on the other hand, its intelligent and adjustable adaptivity improves the accuracy and further extends its application.
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Phiri, Elias, and Wei Wang. "Time Series Analysis and structural break detection: A case of Zambia’s CPI." International Journal of Economic Policy 2, no. 1 (July 8, 2022): 33–43. http://dx.doi.org/10.47941/ijecop.914.
Анотація:
Purpose: By empirically examining Zambia’s CPI between 2010 and 2020, the study attempts to determine the structural change in the time series. The CPI is one of the most important variables for analyzing inflation in macroeconomics, therefore any change in the dynamic must be determined. In this paper change points and dates are highlighted and statistical analysis methods have been employed to explore and discover the underlying patterns and trends of Zambia’s CPI for the past 10 years.
Methodology/approach: Secondary Data from Zambia Statistics Agency (ZamStats.gov.zm) was used for the Study. From 132 elements of observations of time series for 10 years, the detection methods of structural change were employed. The Cumulative Sum Tests (CUSUM test) of Ordinary Least Squares (OLS), Andrew Sup F test, Bai and Perron test, and Chow test were used to detect the model stability and verify the hypothesis using P-value.
Results: The results show that there were five (5) Structural changes or breaks in mean and variance and these were February 2012, February 2014, October 2015, October 2017, and May 2019. The structural breaks are highly suggestive as they appear to broadly coincide with readily identifiable macroeconomic events, increased stock of external debt following the issuance of Eurobonds in 2012, 2014, and 2015, rise increased food prices arising from the adverse impact of erratic rainfall on agricultural output and the pass-through from the depreciation of the Kwacha.
Policy Implication: Based on the study, strong and sound macroeconomic policies are needed to be implemented: Such as debt management and diversification of foreign exchange sources, and increased earnings.
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Jordan, Greta, Sven Goenster-Jordan, Baigal Ulziisuren, and Andreas Buerkert. "Soil Gaseous Emissions and Partial C and N Balances of Small-Scale Farmer Fields in a River Oasis of Western Mongolia." Sustainability 11, no. 12 (June 18, 2019): 3362. http://dx.doi.org/10.3390/su11123362.
Анотація:
During the last decades, Mongolian river oases were subjected to an expansion of farmland. Such intensification triggers substantial gaseous carbon (C) and nitrogen (N) losses that may aggravate disequilibria in the soil surface balances of agricultural plots. This study aims to quantify such losses, and assess the implications of these emissions against the background of calculated partial C and N balances. To this end, CO2, NH3, and N2O soil emissions from carrot, hay, and rye plots were measured by a portable dynamic closed chamber system connected to a photoacoustic multi-gas analyzer in six farms of the Mongolian river oasis Bulgan sum center. Average C and N flux rates (1313 g CO2-C ha−1 h−1 to 1774 g CO2-C ha−1 h−1; 2.4 g NH3-N ha−1 h−1 to 3.3 g NH3-N ha−1 h−1; 0.7 g N2O-N ha−1 h−1 to 1.1 g N2O-N ha−1 h−1) and cumulative emissions (3506 kg C ha−1 season−1 to 4514 kg C ha−1 season−1; 7.4 kg N ha−1 season−1 to 10.9 kg N ha−1 season−1) were relatively low compared to those of other agroecosystems, but represented a substantial pathway of losses (86% of total C inputs; 21% of total N inputs). All C and N balances were negative (−1082 kg C ha−1 season−1 to −1606 kg C ha−1 season−1; −27 kg N ha−1 season−1 to −65 kg N ha−1 season−1). To reduce these disequilibria, application of external inputs may need to be intensified whereby such amendments should be incorporated into soil to minimize gaseous emissions.
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Goldberg, J., and B. W. Peterson. "Reflex and mechanical contributions to head stabilization in alert cats." Journal of Neurophysiology 56, no. 3 (September 1, 1986): 857–75. http://dx.doi.org/10.1152/jn.1986.56.3.857.
Анотація:
Five alert cats were tested for their responses to rotation in a device that allowed rotation of the head on the trunk about a vertical axis passing through the C1-C2 vertebral joint. Electrodes were implanted to record the horizontal and vertical electrooculogram and electromyographic (EMG) activity of the dorsal neck muscles splenius, biventer cervicus, and complexus. Head rotation and torque acting on the head were recorded in the horizontal plane during rotations in the 0.05-5.0 Hz frequency range. Responses were interpreted with reference to a closed-loop dynamic model of the head-neck system. Whole-body rotation (WBR) with no neck movement elicited a vestibulocollic reflex (VCR). Neck muscle EMG lagged the sinusoidal platform rotation by approximately 120 degrees at low frequencies, which represents a 60 degrees lead relative to a perfectly compensatory 180 degrees lag. This phase lead was related to the cumulative eye position of the accompanying horizontal vestibular nystagmus as reported by Vidal et al. Horizontal head torque exhibited a similar low-frequency behavior. At high frequencies, EMG exhibited a progressively increasing phase lead and gain increase typical of a second-order lead system as described in decerebrate cats. Torque, however, showed much less lead and gain increase, presumably because of the low-pass filter properties of the process coupling muscle excitation to torque. Head torque did exhibit a steep increase in gain with frequency and a phase approaching that of platform acceleration at high frequencies when weights were attached to the head to increase its moment of inertia. The same +40 dB/decade gain slope and phase approaching 0 degree was observed during WBR rotation of the anesthetized cat in which head inertia is the only factor contributing to the torque. This dynamic behavior was predicted by the inertial component of the model. In the alert unweighted cat, the inertial torque was smaller than VCR-generated torque at frequencies below 4 Hz. Rotation of the neck with the head held fixed in space (HFS rotation) elicited a cervicocollic reflex (CCR). Neck EMG response was very similar to that observed during WBR, both in dynamic behavior and overall gain. Torque, however, was consistently greater than that generated by WBR and showed a steady increase of 8 dB/decade as frequency rose. The added torque can be attributed to the viscoelastic properties of neck muscles. Driven rotation of the head on the fixed body elicited torques that could be closely approximated by a vector sum of torques observed during WBR and HFS rotations.(ABSTRACT TRUNCATED AT 400 WORDS)
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Gorrab, Azza, Maël Ameline, Clément Albergel, and Frédéric Baup. "Use of Sentinel-1 Multi-Configuration and Multi-Temporal Series for Monitoring Parameters of Winter Wheat." Remote Sensing 13, no. 4 (February 4, 2021): 553. http://dx.doi.org/10.3390/rs13040553.
Анотація:
The present study aims to investigate the potential of multi-configuration Sentinel-1 (S-1) synthetic aperture radar (SAR) images for characterizing four wheat parameters: total fresh mass (TFM), total dry mass (TDM), plant heights (He), and water content (WC). Because they are almost independent on the weather conditions, we have chosen to use only SAR. Samples of wheat parameters were collected over seven fields (three irrigated and four rainfed fields) in Southwestern France. We first analyzed the temporal behaviors of wheat parameters (He, TDM, TFM and WC) between February and June 2016. Then, the temporal profiles of the S-1 backscattering coefficients (VV, VH), the difference (VH − VV), the sum of the polarizations (VH + VV) and their cumulative values are analyzed for two orbits (30 and 132) during the wheat-growing season (from January to July 2016). After that, S-1 signals were statistically compared with all crop parameters considering the impact of pass orbit, irrigation and two vegetative periods in order to identify the best S-1 configuration for estimating crop parameters. Interesting S-1 backscattering behaviors were observed with the various wheat parameters after separating irrigation impacts and vegetative periods. For the orbit 30 (mean incidence angle of 33.6°); results show that the best S-1 configurations (with coefficient of determination (R2) > 0.7) were obtained using the VV and VH + VV as a function of the He, TDM and WC, over irrigated fields and during the second vegetative period. For the orbit 132 (mean incidence angle of 43.4°), the highest dynamic sensitivities (R2 > 0.8) were observed for the VV and VH + VV configurations with He, TDM and TFM over irrigated fields during the first vegetative period. Overall, the sensitivity of S-1 data to wheat variables depended on the radar configuration (orbits and polarizations), the vegetative periods and was often better over irrigated fields in comparison with rainfed ones. Significant improvements of the determination coefficients were obtained when the cumulative (VH + VV) index was considered for He (R² > 0.9), TDM (R² > 0.9) and TFM (R² > 0.75) for irrigated fields, all along the crop cycle. The estimate of WC was more limited (R² > 0.6) and remained limited to the second period of the vegetation cycle (from flowering onwards). Whatever parameters were considered, the relative errors never exceeded 23%. This study has shown the importance of considering the agricultural practices (irrigation) and vegetative periods to effectively monitor some wheat parameters with S-1 data.
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Saini, Jasmine, Wesley P. Gilliam, Julie L. Cunningham, Karthik Thangamuthu, Lucinda M. Gruber, Sumitabh Singh, Bruce Sutor, W. Michael Hooten, and Irina Bancos. "LBSAT59 Overnight Metyrapone Test And Urine Steroid Profiling In Patients Treated With Chronic Opioid Therapy: Prevalence Of Adrenal Insufficiency." Journal of the Endocrine Society 6, Supplement_1 (November 1, 2022): A45—A46. http://dx.doi.org/10.1210/jendso/bvac150.094.
Анотація:
Abstract Background Patients taking chronic opioids are at high risk of opioid induced adrenal insufficiency (OIAI). Previously, we showed that the prevalence of OIAI was 9% based on low morning cortisol, corticotropin (ACTH), and dehydroepiandrosterone sulfate (DHEAS). Data on the overnight metyrapone test to diagnose OIAI are sparse. We aimed to determine the prevalence of OIAI using overnight metyrapone test and identify changes in the steroid metabolome of patients treated with opioids. Methods Cross-sectional study of adult patients treated with opioid therapy of at least 20 morphine milligram equivalents (MME)/day for at least 3 months. Measurements included ACTH, cortisol, and DHEAS. Overnight metyrapone test was administered in all patients, and 24h urine steroid profiling was optional (25 steroids measured by liquid chromatography mass spectrometry1). All patients completed the quality-of-life survey (AddiQoL). Prevalence of OIAI was defined as sum of post-metyrapone 11-deoxycortisol and cortisol of <15 mcg/dL. Result: In 22 patients (median age 59 years [range, 38-74], 9, 41% women), median MME was 33 (20-161) mg, and median cumulative opioid exposure was 245 (10-2550) mg*years. Following the overnight metyrapone test, 7 (32%) patients were diagnosed with OIAI. Patients with OIAI had lower DHEAS concentrations (median of 21 mcg/dL[ 5-113] vs 54 [22-173], p =0. 03), but not cortisol (median 10[5.3-16] mcg/dL vs 13[5.3-22], p=0. 06) or ACTH (median 27[8.1-51] pg/mL vs 26[5.9-55], p=0.8). Patients with OIAI were treated with higher daily MME (100 mg[30-150] vs 30[20-161], p=0. 03) and had a higher cumulative exposure to opioids (median, 660 mg*years [250-2250] vs 150 [10-1288], p =0. 01). AddiQol scores were similar between groups (median of 68[56-84] vs 73[48-83], p= 0.97). Urine steroid profiling was performed in 18 patients. Patients with OIAI demonstrated 4 times lower total urine glucocorticoids (16334 mcg/24h vs 4377 mcg/24h, p=0. 003), all <10% of the reference range, and 3 times lower total urinary androgens (median of 805 mcg/24h vs 2320 mcg/24h, p=0.14). Conclusion Prevalence of OIAI using overnight metyrapone test is high at 32%. Patients diagnosed with OIAI were treated with higher doses of MME/day and had a higher cumulative exposure to opioids when compared to those without OIAI. Applying 24h urine steroid profiling we showed that total glucocorticoids are 4 times lower in those with OIAI (and all <10% of reference ranges) as opposed to those without OIAI. We showed that baseline measurements of ACTH, DHEAS, and cortisol may incorrectly exclude OIAI, and a dynamic test, such as overnight metyrapone test is needed when suspicion for OIAI is high. | 1. Hines JM, Bancos I, Bancos C, et al. High-Resolution, Accurate-Mass (HRAM) Mass Spectrometry Urine Steroid Profiling in the Diagnosis of Adrenal Disorders. Clin Chem. 2017;63(12): 1824-1835. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.
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Kholostov, Konstantin Mikhailovich. "Methods of training managers using cognitive maps and situational modeling." Technology of technosphere safety, no. 99 (2023): 92–102. http://dx.doi.org/10.25257/tts.2023.1.99.92-102.
Анотація:
Introduction. The methods of managing the process of professional training of managers based on the concept of consistent development of a set of professionally significant qualities by conducting simulation games and exercises with students are considered. At the same time, the formal model of the complete training process of the head is presented in the form of the sum of efforts spent on the implementation of private learning processes that allow students to form a cumulative ability to carry out managerial activities. Accordingly, the training of the head is considered successful, provided that the results of passing all stages of training have an acceptable value. Dynamic modeling of the development of situations using actual modeling scenarios based on real situations, the use of semantically significant terms and concepts familiar to managers from the subject area of management of organizational structures, allows you to bring the model situation as close as possible to the real activity of the manager, due to which it is expected to receive high efficiency of their training. Tasks of the work. Development of methods based on modeling situations characteristic of the activities of managers, and conducting simulation games with students, exercises based on the training software and hardware complex in order to improve the practical training of managers. At the same time, it is proposed to implement intelligent management of the educational process by using cognitive maps, and to use models of organizational systems functioning at the regional level for information support. Methods. The dynamic modeling method based on cognitive maps is applied. Predicate calculus methods, situational management methods, including situational modeling and situational analysis are also applied. Results and discussion. The considered methods increase the practical orientation of training, projecting the intended activity of students on the educational process, in connection with which there is a correction of the content of training sessions in the direction of increasing the expediency of the training. To implement the proposed methods in the educational process, it is proposed to use specialized training software and hardware complexes, in connection with which their composition and main functions are considered. Conclusions. The presented methods make it possible to improve the organization and implementation of the educational process on the basis of a situational approach aimed at improving the effectiveness of training managers and strengthening its practical orientation. Keywords: leadership training; education management; cognitive maps; professionally significant qualities; training complexes; situational approach.
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Surana, Lotica. "Uncovering Systematic Risk in Crypto currency Markets: An Empirical Investigation Using DCC-GARCH Model." ANUSANDHAN – NDIM's Journal of Business and Management Research 5, no. 2 (August 26, 2023): 11–26. http://dx.doi.org/10.56411/anusandhan.2023.v5i2.11-26.
Анотація:
This study presents an analysis of the occurrence of structural flaws and spillovers of volatility among eight popular digital currencies, such as Bit coin (BTC), Litecoin (LTC), Ripple (XRP), BNBPrice, DOGECOINPrice,ETHEREUMPrice, TETHERPrice, and USDCOINPrice. The analysis covers the period from December 25, 2019, to August 25, 2022, utilizing various statistical tests such as the Chow Breakpoint Test, Cumulative Sum test, The Granger Causality Test, the LM test for ARCH, and Dynamic Conditional Correlation (DCC) GARCH model. The results of this research reveal being present structural breaks in all the evaluated cryptocurrencies, highlighting the unpredictable nature of the cryptocurrency market. Additionally, these cryptocurrencies exhibit notable volatility spillovers and substantial positive correlations, which point to limited benefits of diversification within the cryptocurrency market. (Chowdhury, 2020; Treiblmaier, 2018; Quispe, 2023). These results have implications for investors, policymakers, and other stakeholders in the cryptocurrency market. The study recommends including cryptocurrencies as an important component in investment portfolios to stimulate returns and reduce overall portfolio risks, it is noted that direct investment incryptocurrencies can generate higher abnormal returns, but this comes with increased risk due to their inherent volatility. Investor preference for firms involved in cryptocurrency is influenced by factors such as legal protection and familiarity. Thus, policymakers should prioritize financial stability and implement careful regulation of cryptocurrency-related announcements to prevent artificial premiums and fraudulent activities (Chowdhury, 2020; Treiblmaier, 2018; Quispe, 2023). Furthermore, the analysis highlights the presence of high volatility spillover effects among certain cryptocurrencies, particularly Bitcoin, Ethereum, and Litecoin.. While volatility offersdiversification advantages, concerns arise due to the lack of intrinsic value and dividends in cryptocurrencies (Özdemir, 2022). The presence of systematic structural breaks suggests the possibility of manipulative behaviors and potential trading strategies that warrant further investigation. The DCC GARCH analysis reveals a high correlation and significant volatility spillover effects among most cryptocurrencies. These findings emphasize the need for a more diversified cryptocurrency market to mitigate risk and promote stability within this emerging financial sector.
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Bardi, Francesca, Merel Bakker, Ayten Elvan-Taşpınar, Monique J. A. Kenkhuis, Jeske Fridrichs, Marian K. Bakker, Erwin Birnie, and Caterina M. Bilardo. "Organ-specific learning curves of sonographers performing first-trimester anatomical screening and impact of score-based evaluation on ultrasound image quality." PLOS ONE 18, no. 2 (February 2, 2023): e0279770. http://dx.doi.org/10.1371/journal.pone.0279770.
Анотація:
Introduction First-trimester anatomical screening (FTAS) by ultrasound has been introduced in many countries as screening for aneuploidies, but also as early screening for fetal structural abnormalities. While a lot of emphasis has been put on the detection rates of FTAS, little is known about the performance of quality control programs and the sonographers’ learning curve for FTAS. The aims of the study were to evaluate the performance of a score-based quality control system for the FTAS and to assess the learning curves of sonographers by evaluating the images of the anatomical planes that were part of the FTAS protocol. Methods Between 2012–2015, pregnant women opting for the combined test in the North-Netherlands were also invited to participate in a prospective cohort study extending the ultrasound investigation to include a first-trimester ultrasound performed according to a protocol. All anatomical planes included in the protocol were documented by pictures stored for each examination in logbooks. The logbooks of six sonographers were independently assessed by two fetal medicine experts. For each sonographer, logbooks of examination 25-50-75 and 100 plus four additional randomly selected logbooks were scored for correct visualization of 12 organ-system planes. A plane specific score of at least 70% was considered sufficient. The intra-class correlation coefficient (ICC), was used to measure inter-assessor agreement for the cut-off scores. Organ-specific learning curves were defined by single-cumulative sum (CUSUM) analysis. Results Sixty-four logbooks were assessed. Mean duration of the scan was 22 ± 6 minutes and mean gestational age was 12+6 weeks. In total 57% of the logbooks graded as sufficient. Most sufficient scores were obtained for the fetal skull (88%) and brain (70%), while the lowest scores were for the face (29%) and spine (38%). Five sonographers showed a learning curve for the skull and the stomach, four for the brain and limbs, three for the bladder and kidneys, two for the diaphragm and abdominal wall and one for the heart and spine and none for the face and neck. Conclusion Learning curves for FTAS differ per organ system and per sonographer. Although score-based evaluation can validly assess image quality, more dynamic approaches may better reflect clinical performance.
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Passamonti, Francesco, Francisco Cervantes, Alessandro Vannucchi, Enrica Morra, Elisa Rumi, Arturo Pereira, Paola Guglielmelli, et al. "A Dynamic Prognostic Model to Predict Survival in Primary Myelofibrosis: a Study of the International Working Group for Myeloproliferative Neoplasm Research and Treatment (IWG-MRT)." Blood 114, no. 22 (November 20, 2009): 3891. http://dx.doi.org/10.1182/blood.v114.22.3891.3891.
Анотація:
Abstract Abstract 3891 Poster Board III-827 Age over 65 years, hemoglobin level lower than 10 g/dL, WBC count greater than 25 × 109/L, peripheral blood blasts equal to or greater than 1%, and presence of constitutional symptoms provide a reliable prediction of survival in patients with primary myelofibrosis (PMF) at diagnosis [Cervantes et al. Blood. 2009 Mar 26;113(13):2895-901]. In fact, based on the presence of 0 (low risk), 1 (intermediate risk-1), 2 (intermediate risk-2) or greater than or equal to 3 (high risk) of the above factors, 4 risk groups with no overlapping in their survival curves were defined. To investigate whether the acquisition of these prognostic factors during follow-up may predict survival anytime, we studied 525 PMF patients regularly followed at each participating Institution from 1980 to 2008. The study was carried out within the IWG-MRT, and an ad hoc database was developed for data collection. Patients with post-polycythemia vera and post-essential thrombocythemia myelofibrosis, and patients with pre-fibrotic myelofibrosis were excluded from this study. Overall, 68 patients (26% of subjects who were below the age of 65 at diagnosis) passed the 65-year age threshold during the study period, 158 (47% of patients without this risk factor at diagnosis) developed anemia, 72 (15% of patients without this risk factor at diagnosis) presented marked leukocytosis, 102 (27% of patients without this risk factor at diagnosis) had more than 1% peripheral blast cells, and 54 (14% of patients without these symptoms at diagnosis) had constitutional symptoms. All variables resulted significant when analyzed as time-dependent covariates in a multivariable Cox proportional hazard regression model, and all of them were therefore included in the subsequent models. Each variable was assigned an integer weight close to the corresponding hazard ratio (HR), and the sum of values obtained was used to allocate the patients into 4 risk categories (low, intermediate-1, intermediate-2, high). We developed 2 separate models, one for all patients (DIPSS) and the other one for patients below the age of 65 (age-adjusted DIPSS), both applicable during the course of the disease. Cumulative survival can be estimated with the Kaplan Meier method. The increased risk of death when changing risk category was estimated as HR. According to DIPSS, the HR was: 4.13 (95% CI: 1.73-9.82; P < .001) if the risk category shifted from low to intermediate-1, 4.61 (95% CI: 3.18-9.82; P < .001) from intermediate-1 to intermediate-2, and 2.54 (95% CI: 1.94-3.31; P < .001) from intermediate-2 to high. According to age-adjusted DIPSS, the HR was 3.97 (95% CI: 1.5-10.5, P = .005) if the risk category shifted from low to intermediate-1, 2.84 (95% CI: 1.46-5.54; P = .002) from intermediate-1 to intermediate-2, and 1.81 (95% CI: 1.08-3.04; P = .025) from intermediate-2 to high. In conclusion, this study shows that age over 65 years, hemoglobin level lower than 10 g/dL, WBC count greater than 25 × 109/L, peripheral blood blasts equal to or greater than 1%, and the presence of constitutional symptoms predict survival independently and in a time-dependent manner in patients with PMF. Both DIPSS and age-adjusted DIPSS allow a reliable prognostic assessment of PMF patients at any time during the clinical course of the disease, and are therefore useful for clinical decision making. Disclosures: No relevant conflicts of interest to declare.
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Zou, Youchun, Chao Xiong, Junhui Yin, Kaibo Cui, Huiyong Deng, Xiujie Zhu, and Shijun Song. "Research on Dynamic Cumulative Damage Effect of Metal Rubber and Stress Wave Propagation Characteristics of Layered Composite Structure." Science of Advanced Materials 13, no. 5 (May 1, 2021): 981–90. http://dx.doi.org/10.1166/sam.2021.3997.
Анотація:
The development of protective materials and structures is of great significance for improving the impact resistance, penetration resistance and spalling resistance of military equipment. At present, the layered composite structure has been widely used due to its good protective performance. In this paper, a special elastic porous material-metal rubber (MR) with excellent cushioning and damping properties was used to prepare high-performance layered composite structures. To begin with, the dynamic mechanical response and the dynamic cumulative damage effect of MR were studied through Split-Hopkinson Pressure Bar (SHPB) tests. Then, the failure form and stress wave propagation characteristics of the layered composite structures were investigated through SHPB tests and finite element method. The results show that repeated impacts can enhance the compactness of MR, thereby increasing the ultimate bearing capacity and energy absorption capacity, which is beneficial for MR to resist repeated impacts. The MR in composite structures can reduce ceramic damage, attenuate stress wave and smooth stress distribution. The titanium alloy on the back of the ceramic will aggravate the damage of the ceramic, and ultra-high molecular weight polyethylene on the back of the ceramic provides cushioning for the ceramic. Therefore, the impact resistance of the composite structure can be improved by adding MR and the reasonable arrangement of materials, and the SiC/UHMWPE/MR/TC4 composite structure has relatively reasonable stress distribution and better protection performance.
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Kong, Bowen, Chen-Xiang Dai, Haibo Hu, Jianzhong Xia, and Shao-Heng He. "The Fractal Characteristics of Soft Soil under Cyclic Loading Based on SEM." Fractal and Fractional 6, no. 8 (July 30, 2022): 423. http://dx.doi.org/10.3390/fractalfract6080423.
Анотація:
Cyclic loading always results in great damage to the pore structure and fractal characteristics of soft soil. Scanning electron microscope (SEM) can help collect data to describe the microstructure of soft soil. This paper conducted a series of SEM tests to interpret the effect of consolidation confining pressure, circulating dynamic stress ratios and overconsolidation ratio on soil’s micro-pore structure and fractal characteristics. The results demonstrate that fractal dimension can well represent the complex characteristics of the microstructure of the soil; the larger the consolidation confining pressure, the greater the cyclic dynamic stress ratio, and the greater the overconsolidation ratio, the smaller the fractal dimension number of soil samples. Finally, an empirical fitting formula for cumulative strain considering microstructure parameters is established through data fitting.
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Kaputkina, Liudmila M., W. G. Prokoszkina, J. Siwka, A. G. Svjażin, Bartosz Koczurkiewicz, and Marcin Knapiński. "The Individual and Cumulative Effect of C and N on the Hardening and Structure of High-Nitrogen Hot Plastic Worked Steels." Materials Science Forum 539-543 (March 2007): 4968–74. http://dx.doi.org/10.4028/www.scientific.net/msf.539-543.4968.
Анотація:
Investigation into the effect of carbon and nitrogen contents of steels with an addition of chromium, nickel and manganese on their structure and properties after thermoplastic treatment has been carried out within the present study. For the physical modeling of thermoplastic treatment processes, a DIL 805A/D dilatometer with a deformation capability and a Gleeble 3800 simulator were used. The effect of carbon and nitrogen contents and the sum of these elements (C+N) on the hardening of the material during hot plastic working. The softening of the material depends on the C/N element ratio. The influence of the constituents under analysis on the dynamics of removal of cold work effects is different; C speeds up, while N slows down this process. The influence of the sum of the elements C and N depends on the type of nonmetallic phase precipitates. The structure and properties of such steels are determined by quenching and tempering cycles.
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Trang, Do Thi Van, and Jo-Hui Chen. "Applications of Long-Memory and Structure Breaks for Carbon Indexes." International Journal of Energy Economics and Policy 13, no. 3 (May 17, 2023): 579–85. http://dx.doi.org/10.32479/ijeep.14289.
Анотація:
This paper aims to investigatethe long-memory properties of four carbon indexes by utilizing the autoregressive frictionally integrated moving average–fractionally integrated general autoregressive conditional heteroskedasticity models. First, this study discovered a significant long-memory effect for two carbon indexes such as CCX and JOI, whereas others like CER and EUA possess intermediate memory in the returns. Second, the multiple structure breaks in the four carbon indexes were examined using the iterated cumulative sum of squares algorithm. Evidence shows that the sudden shifts are mainly attributed to macroeconomic factors, energy dynamics, and political policies.
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Postnikov, Eugene B. "Reproducing country-wide COVID-19 dynamics can require the usage of a set of SIR systems." PeerJ 9 (January 7, 2021): e10679. http://dx.doi.org/10.7717/peerj.10679.
Анотація:
This work shows that simple compartmental epidemiological models may not reproduce actually reported country-wide statistics since the latter reflects the cumulative amount of infected persons, which in fact is a sum of outbreaks within different patched. It the same time, the multilogistic decomposition of such epidemiological curves reveals components, which are quite close to the solutions of the SIR model in logistic approximations characterised by different sets of parameters including time shifts. This line of reasoning is confirmed by processing data for Spain and Russia in details and, additionally, is illustrated for several other countries.
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Andreev, Vadim. "Statistical Evaluation of Style Dynamics: Lyrical Poems by V. Nabokov in the Mirror of Parts of Speech." Izvestia of Smolensk State University, no. 4(60) (April 12, 2023): 81–91. http://dx.doi.org/10.35785/2072-9464-2022-60-4-81-91.
Анотація:
The article utilizes quantitative methods of analysis to obtain objective indices which make it possible to evaluate a separate text and the style of the author. The author applies the techniques of textometry (analysis of PoS ratio, type of
description, cumulative sum) in order to establish the degree of text stability /dynamics and stability / variability of individual style in general.
The database includes verse texts of Vladimir Nabokov created during different periods of creative activity. Poetry was an essential and inseparable part of his writing (as the writer and poet stated himself) which proves the non-accidental character of parameters of his poetic texts and their high relevance for the
study of his style. Only texts not less than 30 lines are included in the database in order to avoid fluctuations in frequency of linguistic elements and ensure comparability of the research material.
The use of Busemann and variability coefficients made it possible to define the ratio of verbal / nominal description in the texts, while analysis of cumulative sum – the ratio of nouns / verbs in the texts in dynamics (from the beginning to its end). The calculated power function provides precise approximation of the data.
The obtained results support the conclusion about the existence of hidden tendencies in the distribution of words of different parts of speech in Nabokov's text, about the growth of variability of their frequencies in the second period of Nabokov’s creative activity, as well as about steady strengthening of the tendency
of text verbality growth over the lifespan of the poet.
41
Fu, X. Q., Y. Li, W. J. Su, J. L. Shen, R. L. Xiao, C. L. Tong, and J. Wu. " Annual dynamics of N2O emissions from a tea field in southern subtropical China." Plant, Soil and Environment 58, No. 8 (August 21, 2012): 373–78. http://dx.doi.org/10.17221/719/2011-pse.
Анотація:
The annual dynamics of N<sub>2</sub>O emissions from a tea field in southern subtropical China was observed in situ weekly in 2010 using a static closed chamber – gas chromatography (GC) method for three treatments: non-fertilised (CK), conventional (CON) and rice straw mulching (SM). The annual N<sub>2</sub>O emissions for CK, CON and SM were 7.1, 17.2 and 16.7 kg N/ha/year, respectively. The N<sub>2</sub>O emission factors for the CON and SM treatments were estimated as 2.23% and 1.91% of the total fertiliser N applied, respectively. Rice straw mulching exhibited a potential to reduce the N<sub>2</sub>O emissions from the tea field, but not statistically significant (P = 0.82). The daily N<sub>2</sub>O fluxes were positively correlated with the air temperature. The cumulative precipitation of the previous five days was significantly correlated with the daily N<sub>2</sub>O fluxes of CON. The soil water contents were significantly correlated with the daily N<sub>2</sub>O fluxes in the three treatments. The N<sub>2</sub>O fluxes from CON had a more significant correlation with the soil NH<sub>4</sub><sup>+</sup>-N contents than with the soil NO<sub>3</sub><sup>–</sup>-N contents, while the N<sub>2</sub>O fluxes from SM showed an inverse pattern. The N<sub>2</sub>O fluxes from CK did not show any significant relationship with the soil mineral N content.
42
Viegas, Eduardo, Stuart P. Cockburn, Henrik J. Jensen, and Geoffrey B. West. "The dynamics of mergers and acquisitions: ancestry as the seminal determinant." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 470, no. 2171 (November 8, 2014): 20140370. http://dx.doi.org/10.1098/rspa.2014.0370.
Анотація:
Understanding the fundamental mechanisms behind the complex landscape of corporate mergers and acquisitions is of crucial importance to economies across the world. Adapting ideas from the fields of complexity and evolutionary dynamics to analyse business ecosystems, we show here that ancestry, i.e. the cumulative sum of historical mergers across all ancestors, is the key characteristic to company mergers and acquisitions. We verify this by comparing an agent-based model to an extensive range of business data, covering the period from the 1830s to the present day and a range of industries and geographies. This seemingly universal mechanism leads to imbalanced business ecosystems, with the emergence of a few very large, but sluggish ‘too big to fail’ entities, and very small, niche entities, thereby creating a paradigm where a configuration akin to effective oligopoly or monopoly is a likely outcome for free market systems.
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ZHANG, YANG, RENJIE WU, YING HU, YU DONG, LIFENG SHEN, LIJUN CHEN, KELVIN K. L. WONG, DHANJOO N. GHISTA, and DAN SHOU. "STUDY OF THE DIFFERENT RELEASE CHARACTERISTICS OF ANTIBIOTICS FROM PATIENTS: A DYNAMIC ELUTING SYSTEM TO INVESTIGATE DRUG RELEASE FROM ANTIBIOTIC-IMPREGNATED CALCIUM SULFATE DELIVERY." Journal of Mechanics in Medicine and Biology 15, no. 01 (February 2015): 1550012. http://dx.doi.org/10.1142/s0219519415500128.
Анотація:
Background: Antibiotic-impregnated calcium sulfate delivery systems (ACDS) are commonly used to treat chronic osteomyelitis. Our research is to investigate drug release in vitro over a longer period, as a cautious predictor of in vivo release. Methods: The local release behavior of antibiotic in vitro was simulated. The consecutive dynamic eluting experiment was performed based on the pro-operative characteristic of osteomyelitis patients and the determined results of drug concentration in the human drainage tissue fluid (DTF). The concentration of each drug in the receiving solution was detected by ultra-performance liquid chromatography-tandem quadrupole detector mass spectrometry. The ACDS was reviewed by scanning electronic microscopy (SEM) after 48 h, and prepared to be eluted for another examination after 33 days. The mechanism of antibiotic release was analyzed by using the Ritger–Peppas and Weibull equations. Results: The cumulative release rate of vancomycin in a vancomycin-calcium sulfate delivery system (VCDS) was 77.50 % (3.0 mm diameter) and 72.43 % (4.8 mm diameter), while that of the tobramycin in a tobramycin-calcium sulfate delivery system (TCDS) was 88.0 % (3.0 mm diameter) and 84.55 % (4.8 mm diameter). At the 15th day, approximately 27.92% of vancomycin was and 29.35% of tobramycin was released from the local implant in vivo. Using SEM, numerous vancomycin and tobramycin particles were found to be attached to the columnar calcium sulfate crystals at the start of the experiment. The release behavior of the two antibiotics followed a combination of Fickian diffusion and Case II transport mechanisms within the first 48 h, and a Fickian diffusion mechanism during the subsequent time period. The correlation coefficient of tobramycin and vancomycin in vivo and in vitro was 0.9704–0.9949 and 0.9549–0.9782, respectively. Conclusion: A good correlation of the in vivo and in vitro cumulative release rates was observed by comparing the cumulative release rate of drugs in vitro by means of the dynamic eluting model, and in the DTF. Therefore, our study has proved that it is possible to use the dynamic eluting model as a cautious predictor of in vivo release.
44
Jiang, Zhuhua, Walid Mensi, and Seong-Min Yoon. "Risks in Major Cryptocurrency Markets: Modeling the Dual Long Memory Property and Structural Breaks." Sustainability 15, no. 3 (January 24, 2023): 2193. http://dx.doi.org/10.3390/su15032193.
Анотація:
This study estimates the effects of the dual long memory property and structural breaks on the persistence level of six major cryptocurrency markets. We apply the Bai and Perron structural break test, Inclán and Tiao’s iterated cumulative sum of squares (ICSS) algorithm, and the fractionally integrated generalized autoregressive conditional heteroscedasticity (FIGARCH) model, with different distributions. The results show that long memory and structural breaks characterize the conditional volatility of cryptocurrency markets, confirming our hypothesis that ignoring structural breaks leads to an underestimation of the persistence of volatility modeling. The ARFIMA-FIGARCH model, with structural breaks and a skewed Student–t distribution, fits the cryptocurrency market’s price dynamics well.
45
Tsivenko, O. I., M. S. Matvieienko, A. L. Lіashok, O. Yu Bychkova, and V. M. Tsivenko. "Monitoring of infusion therapy in patients with reduced cardiac reserve during abdominal operations." 48, no. 48 (March 29, 2024): 73–85. http://dx.doi.org/10.26565/2313-6693-2024-48-08.
Анотація:
Background. In the pathogenesis of many intra- and postoperative complications, the composition, volume and rate of infusion therapy (IT) play a significant role. This problem is especially relevant for patients with concomitant chronic pathology of the cardiovascular, respiratory systems and kidneys. Informative indicators for assessing the correctness of IT and early diagnosis of intraoperative complications associated with errors in its implementation are complex monitoring of functional indicators of the cardiovascular and respiratory systems. Purpose – of the study is to investigate changes in biochemical markers of heart failure and ultrasound signs of venous stasis in two modes of infusion therapy (restrictive and liberal), on the basis of a comparative study, to determine the optimal mode of perioperative IT in patients undergoing elective surgery for diseases of the abdominal cavity and have comorbid pathology in the form of coronary heart disease (CHD) and heart failure (HF). Materials and Methods. 86 patients were included in a single-center, prospective, randomized study. All patients were randomly divided into two groups depending on the mode of intraoperative IT: in the first group (n = 44) – a restrictive mode of 5–8 ml/kg/hour was applied, in the second (n = 42) – a liberal mode. Echocardiography was performed at the stages of the study. Heart contractility, central hemodynamics, and ejection fraction were evaluated. An ultrasound scan of the inferior vena cava (IVC) was performed during breathing as a non-invasive method of assessing the intravascular blood volume. The diameter of the vein during inhalation and exhalation was evaluated. Based on the respiratory change in the diameter of the IVC, the caval index is calculated, which is expressed as a percentage. An index approaching 100% indicates near-complete collapse and probable volume depletion, while an index close to 0% indicates minimal collapse and intravascular overflow. Ultrasound of the lungs was performed according to the BLUE protocol with a convex sensor in 8 zones along the front chest wall. The severity of pulmonary congestion was assessed based on the sum of B-lines: 5 and less – no congestion, 6 to 15 – slight congestion, 15 to 29 – moderate, 30 and more – significant. Results. The conducted study shows the advantage of the restrictive regimen of IT in patients with concomitant coronary artery disease and minimal signs of congestive heart failure during abdominal surgical operations. The regime with restriction of intravenous fluid administration was better, as it reduces venous congestion, reduces the amount of fluid in the interstitial space of the lungs, causes a smaller compensatory reaction of the cardiovascular system to infusion with normal values of NT-proBNP. The task of the anesthesiologist in this case is careful control of daily and cumulative water balance, adequate monitoring of indicators of the cardiovascular system, use of modern ultrasound technologies and protocols for controlling volemic status, assessment of the dynamics of biomarkers of heart failure, which will allow complex abdominal operations to be safely performed in patients with reduced cardiac reserve. Conclusions. As a result of the conducted research, it was established that: the use of a liberal regimen of infusion therapy in the perioperative period in patients with coronary heart disease and HF I, I-II FC compared to a restrictive regimen leads to a statistically significant increase in biomarkers of heart failure and ultrasound signs of volemic overload. The restrictive regimen of IT in a dose of 5–8 ml/kg/hour, in comparison with a liberal one in a dose of 12–15 ml/kg/hour, can be recognized as optimal and safe in patients with coronary heart disease and HF I, I-II FC during surgery on the organs of the abdominal cavity. The use and widespread implementation in practice of complex determination of the level of the amino-terminal prohormone of brain natriuretic peptide (NT-proBNP) NT-proBNP, non-invasive methods of ultrasound of the heart – echocardiography, ultrasound of the lungs and central vessels – assessment of the dynamic filling of the inferior vena cava (IVC) allows significantly supplement clinical information on volemic status, venous stasis, contractility of the heart and fluid retention in the interstitial space of the lungs and may be key in the prevention of cardiac complications in this category of patients.
46
Takáč, Jozef. "Assessment of Drought in Agricultural Regions of Slovakia Using Soil Water Dynamics Simulation." Agriculture (Pol'nohospodárstvo) 59, no. 2 (June 1, 2013): 74–87. http://dx.doi.org/10.2478/agri-2013-0007.
Анотація:
Assessment of agronomic drought occurrence and severity in agricultural regions of Slovakia is presented in the paper. Drought severity assessment is based on the soil water dynamics simulation by agroecological model Daisy. Daily meteorological data from the years 1961-2012 from 31 localities were used in simulations. Criteria for the drought occurrence were 1) available soil water content below 50% of available water capacity, 2) soil water content below long-term average soil water content and 3) duration of continuous drought for fifteen or more days. Standardized index of daily available soil water content was used for drought severity classification. According to the index the drought is categorized into four degrees of severity from mild to extreme drought. Cumulative sum of available soil water index was used to drought quantification throughout its duration. Normal climate period 1961- 1990 was chosen as reference period to enable historical comparison of drought severity as well as climate change impacts. Extreme drought of the largest spatial extent was identified in 1990. Extreme drought occurred regionally in the southwest Slovakia in 1978 and in the southeast Slovakia in 1986, respectively.
47
Agraharam, Gopikrishna, Agnishwar Girigoswami, and Koyeli Girigoswami. "Nanoencapsulated Myricetin to Improve Antioxidant Activity and Bioavailability: A Study on Zebrafish Embryos." Chemistry 4, no. 1 (December 31, 2021): 1–17. http://dx.doi.org/10.3390/chemistry4010001.
Анотація:
Flavonoids are natural polyphenolic compounds that mainly possess antioxidant properties due to more hydroxyl groups in their structure and play an important role in combatting many diseases. Myricetin is a flavonoid found in grapes, green tea, fruits, and vegetables and is not only an antioxidant but also is a pro-oxidant. Myricetin is sparingly soluble in water and restricts its properties due to low bioavailability. The present study reports the liposomal nanoformulations of myricetin to improve its bioavailability with reduced pro-oxidant activity. The nanoformulated myricetin was characterized using different photophysical tools, such as dynamic light scattering (DLS), zeta potential, and scanning electron microscopy (SEM). The effect of nanoencapsulated myricetin on the developing zebrafish embryo was studied in terms of microscopic observations, cumulative hatchability, and antioxidant activities, such as catalase, glutathione peroxidase, and superoxide dismutase, after treating the zebrafish embryo with standard oxidant hydrogen peroxide. The results obtained from the cumulative hatchability, developmental studies, and antioxidant assays indicated that the liposomal nanoformulation of myricetin had enhanced antioxidant activity, leading to defense against oxidative stress. The formulation was highly biocompatible, as evidenced by the cumulative hatching studies as well as microscopic observations. The positive effects of liposomal nanoformulation on zebrafish embryos can open an avenue for other researchers to carry out further related research and to check its activities in clinical studies and developmental studies.
48
Sørensen, Søren S., Christophe A. N. Biscio, Mathieu Bauchy, Lisbeth Fajstrup, and Morten M. Smedskjaer. "Revealing hidden medium-range order in amorphous materials using topological data analysis." Science Advances 6, no. 37 (September 2020): eabc2320. http://dx.doi.org/10.1126/sciadv.abc2320.
Анотація:
Despite the numerous technological applications of amorphous materials, such as glasses, the understanding of their medium-range order (MRO) structure—and particularly the origin of the first sharp diffraction peak (FSDP) in the structure factor—remains elusive. Here, we use persistent homology, an emergent type of topological data analysis, to understand MRO structure in sodium silicate glasses. To enable this analysis, we introduce a self-consistent categorization of rings with rigorous geometrical definitions of the structural entities. Furthermore, we enable quantitative comparison of the persistence diagrams by computing the cumulative sum of all points weighted by their lifetime. On the basis of these analysis methods, we show that the approach can be used to deconvolute the contributions of various MRO features to the FSDP. More generally, the developed methodology can be applied to analyze and categorize molecular dynamics data and understand MRO structure in any class of amorphous solids.
49
Even-Zohar, Itamar. "Intercultural competition over resources via contests for symbolic capitals." Semiotica 2020, no. 232 (February 25, 2020): 235–50. http://dx.doi.org/10.1515/sem-2019-0038.
Анотація:
AbstractIntergroup competition over resources is attested since the dawn of history. Written and archaeological evidence go back to at least the fourth millennium BC. According to accepted views, evolution has favored humans because of their ability to have cumulative cultures, which has made flexible adaptation possible. One major aspect of this adaptation has been the ability to handle power contests without engaging physical force. Instead, increasing prestige dynamics has allowed contest management by displaying symbolic assets. These have growingly been instrumental in deterring external assaults, thus guaranteeing the possession – or expansion – of a group’s resources. However, while material assets are believed to create status by the evidence of their tangible usefulness (such as foods, husbandry and tools), symbolic assets are by definition subject to ongoing negotiation, entirely dependent on being socio-semiotically recognized as types of capital. Symbolic stock exchanges thus appear to have been determinative since antiquity in hierarchizing ethnic and political groups fighting over resources, prioritizing ones over the others. They have culminated in repertoires of more solid tangible and intangible assets, from impressive buildings, city gates, gardens and temples, to ideas such as freedom, quality of life and wealth, justice, personal security, or whatever values that have gained universal recognition. The article discusses the creation and expansion of such symbolic repertoires and their uncertain position in recent times.
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Chen, Ning, An Chen, and Xiaohui Yao. "Trajectory Tracking of COVID-19 Epidemic Risk Using Self-organizing Feature Map." Bulletin of the Chinese Academy of Sciences 36 (2022): 2022003. http://dx.doi.org/10.1051/bcas/2022003.
Анотація:
The ongoing COVID-19 has become a worldwide pandemic with increasing confirmed cases and deaths across the globe. By July 2022, the number of cumulative confirmed cases reported to the World Health Organization (WHO) has risen to 550 million, with more than 6 million deaths in total. The analysis of its epidemic risk remains the focus of attention all over the world for a long time. The Self-organizing feature map (SOM), a vector quantization method, offers a data mapping approach to tracking the response of time series data on a well-trained map. This study aims at a trajectory tracking of COVID-19 epidemic risk in 237 countries measured by the number of new confirmed cases and deaths per day for over one year. A hybrid clustering method uses SOM and K-means to generate a risk map and then displays the trajectory of daily risk on the map. The experimental results demonstrate the promising functionality of SOM for trajectory tracking and give experts insights into the dynamic changes of COVID-19 risk.