<strong>Background: </strong>Campus connectedness is a kind of social connectedness that determines the students’ perception of their belonging to the other populace of the campus that includes students, ...<strong>Background: </strong>Campus connectedness is a kind of social connectedness that determines the students’ perception of their belonging to the other populace of the campus that includes students, teachers, administrators, and other staff. Campus connectedness plays a significant role in determining stress, anxiety, and depression among students. The purpose of the study was to examine the relationship of campus connectedness to stress, anxiety, and depression among nursing students. <strong>Methods:</strong> This cross-sectional analytical study was conducted among 680 undergraduate nursing students from nine nursing colleges affiliated with a university in Kathmandu Valley. Data were collected from June 1, 2018, through July 10, 2018. Depression, Anxiety, Stress Scale and Campus Connectedness Scale were used to collect data. The data were analyzed using Statistical Package for Social Sciences version 23. A one-way multivariate analysis of variance (MANOVA) test was used to examine the relationship of campus connectedness to stress, anxiety, and depression. Discriminant analysis was done as a follow-up procedure to MANOVA. <strong>Results: </strong>Students had moderate to extremely severe levels of depression (51.7%), anxiety (72.9%) and stress (47%). High campus connectedness score was observed (M = 62.42;SD = 9.79). Statistically significant differences were found among the levels of campus connectedness on the outcome variables, Wilks’ lambda (<em>λ</em>) = 0.90, <em>F</em>(3, 676) = 24.56, <em>p</em> < 0.001. Depression demonstrated the strongest relationship with the discriminant function. <strong>Conclusions: </strong>There was a significant relationship of campus connectedness to stress, anxiety, and depression. Despite the high level of campus connectedness, students had moderate to severe levels of stress, anxiety, and depression. The campus adminstration must take measures and efforts to provide conducive environment and counseling services for the wellbeing of their students.展开更多
Pig breeding is generally conducted among many herds, so EBV comparisons across populationsare necessary. Genetic connectedness is required for reliable between-farm animal EBV comparisons.Five quantitative overall co...Pig breeding is generally conducted among many herds, so EBV comparisons across populationsare necessary. Genetic connectedness is required for reliable between-farm animal EBV comparisons.Five quantitative overall connectedness measures among populations have been proposed so far,coefficient of connectedness(γ*), coefficient of determination (CD) and overall indices ofprecision, connectedness rating, number of direct genetic links between subpopulations due tocommon sires and dams (GLt), and average genetic covariance (AGC) are reviewed and theirproperties are discussed in this paper. It is recommended to use AGC at present for measuringgenetic connectedness between herds.展开更多
This study investigates the dynamic connectedness between stock indices and the effect of economic policy uncertainty(EPU)in eight countries where COVID-19 was most widespread(China,Italy,France,Germany,Spain,Russia,t...This study investigates the dynamic connectedness between stock indices and the effect of economic policy uncertainty(EPU)in eight countries where COVID-19 was most widespread(China,Italy,France,Germany,Spain,Russia,the US,and the UK)by implementing the time-varying VAR(TVP-VAR)model for daily data over the period spanning from 01/01/2015 to 05/18/2020.Results showed that stock markets were highly connected during the entire period,but the dynamic spillovers reached unprecedented heights during the COVID-19 pandemic in the first quarter of 2020.Moreover,we found that the European stock markets(except Italy)transmitted more spillovers to all other stock markets than they received,primarily during the COVID-19 outbreak.Further analysis using a nonlinear framework showed that the dynamic connectedness was more pronounced for negative than for positive returns.Also,findings showed that the direction of the EPU effect on net connectedness changed during the pandemic onset,indicating that information spillovers from a given market may signal either good or bad news for other markets,depending on the prevailing economic situation.These results have important implications for individual investors,portfolio managers,policymakers,investment banks,and central banks.展开更多
Analyzing comovements and connectedness is critical for providing significant implications for crypto-portfolio risk management.However,most existing research focuses on the lower-order moment nexus(i.e.the return and...Analyzing comovements and connectedness is critical for providing significant implications for crypto-portfolio risk management.However,most existing research focuses on the lower-order moment nexus(i.e.the return and volatility interactions).For the first time,this study investigates the higher-order moment comovements and risk connectedness among cryptocurrencies before and during the COVID-19 pandemic in both the time and frequency domains.We combine the realized moment measures and wavelet coherence,and the newly proposed time-varying parameter vector autoregression-based frequency connectedness approach(Chatziantoniou et al.in Integration and risk transmission in the market for crude oil a time-varying parameter frequency connectedness approach.Technical report,University of Pretoria,Department of Economics,2021)using intraday high-frequency data.The empirical results demonstrate that the comovement of realized volatility between BTC and other cryp-tocurrencies is stronger than that of the realized skewness,realized kurtosis,and signed jump variation.The comovements among cryptocurrencies are both time-dependent and frequency-dependent.Besides the volatility spillovers,the risk spillovers of high-order moments and jumps are also significant,although their magnitudes vary with moments,making them moment-dependent as well and are lower than volatility connectedness.Frequency connectedness demonstrates that the risk connectedness is mainly transmitted in the short term(1–7 days).Furthermore,the total dynamic connectedness of all realized moments is time-varying and has been significantly affected by the outbreak of the COVID-19 pandemic.Several practical implications are drawn for crypto investors,portfolio managers,regulators,and policymakers in optimizing their investment and risk management tactics.展开更多
A fast interactive segmentation algorithm of image-sequences based on relative fuzzy connectedness is presented. In comparison with the original algorithm, the proposed one, with the same accuracy, accelerates the seg...A fast interactive segmentation algorithm of image-sequences based on relative fuzzy connectedness is presented. In comparison with the original algorithm, the proposed one, with the same accuracy, accelerates the segmentation speed by three times for single image. Meanwhile, this fast segmentation algorithm is extended from single object to multiple objects and from single-image to image-sequences. Thus the segmentation of multiple objects from complex hackground and batch segmentation of image-sequences can be achieved. In addition, a post-processing scheme is incorporated in this algorithm, which extracts smooth edge with one-pixel-width for each segmented object. The experimental results illustrate that the proposed algorithm can obtain the object regions of interest from medical image or image-sequences as well as man-made images quickly and reliably with only a little interaction.展开更多
Two pig populations were simulated with Monte Carlo method; each consisted of 5 boars and 50 sows per generation. Genetic connectedness between herds was established by randomly selecting 1 or 2 boars from one populat...Two pig populations were simulated with Monte Carlo method; each consisted of 5 boars and 50 sows per generation. Genetic connectedness between herds was established by randomly selecting 1 or 2 boars from one population to mate sows of the other population. Breeding pigs were selected within populations according to animal model BLUP. The benefits of genetic connectedness between herds were examined. The results showed that, the average coefficients of inbreeding decreased, while the cumulative selection responses of populations increased, and the higher response occurred randomly in the two populations at generation 5 with the increase of the genetic connectedness between herds. Selection response was affected by genetic connectedness and trait heritability, the lower heritability and higher connectedness, the better selection results. When the number of exchanged litters between populations per generation was 6 litters, the selection results reached a reflection point; if the number of exchanged litters between populations increased further from this point, neither the increase of the cumulative selection responses nor the decrease of coefficients of inbreeding was significant.展开更多
This paper deals with the connectedness of the cone-efficient solution set for vector optimization in locally convex Hausdorff topological vector spaces. The connectedness of the cone-efficient solution set is proved ...This paper deals with the connectedness of the cone-efficient solution set for vector optimization in locally convex Hausdorff topological vector spaces. The connectedness of the cone-efficient solution set is proved for multiobjective programming defined by a continuous one-to-one cone-quasiconvex mapping on a compact convex set of alternatives. During the proof, the generalized saddle theorem plays a key role.展开更多
We examine the dynamics of liquidity connectedness in the cryptocurrency market.We use the connectedness models of Diebold and Yilmaz(Int J Forecast 28(1):57–66,2012)and Baruník and Křehlík(J Financ Econom ...We examine the dynamics of liquidity connectedness in the cryptocurrency market.We use the connectedness models of Diebold and Yilmaz(Int J Forecast 28(1):57–66,2012)and Baruník and Křehlík(J Financ Econom 16(2):271–296,2018)on a sample of six major cryptocurrencies,namely,Bitcoin(BTC),Litecoin(LTC),Ethereum(ETH),Ripple(XRP),Monero(XMR),and Dash.Our static analysis reveals a moderate liquidity connectedness among our sample cryptocurrencies,whereas BTC and LTC play a significant role in connectedness magnitude.A distinct liquidity cluster is observed for BTC,LTC,and XRP,and ETH,XMR,and Dash also form another distinct liquidity cluster.The frequency domain analysis reveals that liquidity connectedness is more pronounced in the short-run time horizon than the medium-and long-run time horizons.In the short run,BTC,LTC,and XRP are the leading contributor to liquidity shocks,whereas,in the long run,ETH assumes this role.Compared with the medium term,a tight liquidity clustering is found in the short and long terms.The time-varying analysis indicates that liquidity connectedness in the cryptocurrency market increases over time,pointing to the possible effect of rising demand and higher acceptability for this unique asset.Furthermore,more pronounced liquidity connectedness patterns are observed over the short and long run,reinforcing that liquidity connectedness in the cryptocurrency market is a phenomenon dependent on the time–frequency connectedness.展开更多
Estimating genetic connectedness among herds is important for the accuracy of dairy cattle genetic evaluation. When selecting between animals raised in different herds, the accuracy of their genetic evaluations can be...Estimating genetic connectedness among herds is important for the accuracy of dairy cattle genetic evaluation. When selecting between animals raised in different herds, the accuracy of their genetic evaluations can be influenced by the degree of connectedness among these herds. In this study, two methods were used to measure genetic connectedness, CR (genetic connectedness rating ) and GLt (total number of direct genetic links between group), among herds from Beijing, Shanghai, and Tianjin. Genetic connectedness between the herds from Beijing and Tianjin was 23.95%, between Beijing and Shanghai was 17. 10%, and between Shanghai and Tianjin it was 14.28%. Genetic connectedness between herds from Beijing and Tianjin was the highest and that between Shanghai and Tianjin was the lowest. The correlation coefficient for the two methods was 0. 808. Some suggestions for improved genetic evaluation of dairy cattle were also discussed.展开更多
“Connectedness” is an essential component of genetic evaluations. The degree of connectedness affects the accuracy of comparing estimated breeding values (EBVs) from one herd or contemporary group to the other. It c...“Connectedness” is an essential component of genetic evaluations. The degree of connectedness affects the accuracy of comparing estimated breeding values (EBVs) from one herd or contemporary group to the other. It can be measured through Connectedness Rating (CR) which is based on variances and covariance among the estimates of contemporary group effects. A computing algorithm and a computer program for estimating CR is available. The minimum required level of connectedness depends upon the size of the contemporary groups, the level of accuracy and the residual variance. About 48% CR is required to detect differences between EBVs that are greater than 20% of the standard deviation in the trait, for group sizes of about 100 animals. Higher levels are necessary for smaller group sizes and for more accurate comparisons. Breeders participating in a common genetic evaluation program should therefore exchange their superior genetics and possibly use some common testing facilities for meaningful estimates of breeding values. Maintaining a good connectedness level will make the genetic evaluation program more useful for selection of superior breeding animals and achieving faster rate of genetic progress.展开更多
Social connectedness has been identified as a protective factor for a range of health issues however the literature is not conclusive. The high prevalence of hazardous alcohol consumption and mental health problems am...Social connectedness has been identified as a protective factor for a range of health issues however the literature is not conclusive. The high prevalence of hazardous alcohol consumption and mental health problems among university students along with the potential for the university as a setting for health promotion prompted this study. The study aims to explore the association between levels of alcohol consumption, mental health, social connectedness and social identity among university students. Online data were collected from a random sample of university undergraduate students (n = 2506) aged 18 - 24 years old. Outcomes were measured using the Alcohol Use Disorders Identification Test (AUDIT), the Kessler Psychological Distress Scale, Social Connectedness Scale, Social Identity Scale and measures of paid employment and study (hours), and participation in sports and other clubs. The majority of students had consumed alcohol in the last 12 months (87%). Of these students 38% reported to drink at hazardous levels (AUDIT ≥ 8). When all factors were considered: gender, living arrangements, being a domestic student, hours spent at work, participation in university and community sport, higher levels of psychological distress, higher levels of social connectedness, and lower levels of social identity were significant predictors of hazardous alcohol consumption. The finding highlights the need for the inclusion of integrated, multi-strategy health promotion interventions on campus. Further exploration of the associations between social connectedness and social identity as influences of health behaviors will better inform the development of targeted strategies for specific groups.展开更多
The concepts of connectedness and locally connectedness is introduced for rightside idempotent quantales. Some properties of connected quantale are studied, and then the equivalent characterization of connected quanta...The concepts of connectedness and locally connectedness is introduced for rightside idempotent quantales. Some properties of connected quantale are studied, and then the equivalent characterization of connected quantale is also given.展开更多
The connectedness of the invertibles question for arbitrary nest has been reduced to the case of the lower triangular operators with respect to a fixed orthonormal basis en for n 1. For each f ∈ H∞, let Tf be the To...The connectedness of the invertibles question for arbitrary nest has been reduced to the case of the lower triangular operators with respect to a fixed orthonormal basis en for n 1. For each f ∈ H∞, let Tf be the Toeplitz operator. In this paper we prove that Tf can be connected to the identity through a path in the invertible group of the lower triangular operators if f satisfies certain conditions.展开更多
The topological study of connectedness is heavily geometric or visual. Connectedness and connectedness-like properties play an important role in most topological characterization theorems, as well as in the study of o...The topological study of connectedness is heavily geometric or visual. Connectedness and connectedness-like properties play an important role in most topological characterization theorems, as well as in the study of obstructions to the extension of functions. In this paper, the behaviour of these properties in the realm of closure spaces is investigated using the class of perfect mappings. A perfect mapping is a type of map under which the image generally inherits the properties of the mapped space. It turns out that the general behaviour of connectedness properties in topological spaces extends to the class of isotone space.展开更多
This article presents the results of a study that evaluated VinclesBCN during COVID-19. This digital-based public social service aims to prevent loneliness and isolation in +65-year-old adults living in Barcelona. Thr...This article presents the results of a study that evaluated VinclesBCN during COVID-19. This digital-based public social service aims to prevent loneliness and isolation in +65-year-old adults living in Barcelona. Through service user(N = 12) and professional(N = 6) interviews and a questionnaire with service users(N = 255), we demonstrate the pivotal role of digital connectedness in transforming VinclesBCN into a lifeline during the pandemic. The analysis revealed the importance of sociability, social support, and, especially, entertainment in coping with pandemic fatigue and facilitating social connectivity and support among users. Users engaged in activities such as sharing images, songs, memes, and daily greetings to provide proximity, sociability, and care among users, whether they belonged to preexisting groups or were newly introduced to the platform. It also facilitated the identification of individuals who needed companionship, comfort, or more specialized support. The findings emphasize the significance of entertainment as a resilience-building strategy during times of uncertainty. Despite the positive impact, not all users equally used the platform. Non-use was strongly associated with being a woman, having a low educational level, having preexisting social relationships, less time of enrolment in the platform, as well as a high perception of loneliness, poor self-reported health, and low mood. The article underscores the need for further research into older adults' digital engagement during crises, its role in building resilience, and advocating for inclusive digital interventions that take into account diverse older adults' needs and experiences in crisis contexts.展开更多
Brine shrimp(Artemia)has existed on Earth for 400 million years and has major ecological importance in hypersaline ecosystems.As a crucial live food in aquaculture,brine shrimp cysts have become one of the most import...Brine shrimp(Artemia)has existed on Earth for 400 million years and has major ecological importance in hypersaline ecosystems.As a crucial live food in aquaculture,brine shrimp cysts have become one of the most important aquatic products traded worldwide.However,our understanding of the biodiversity,prevalence and global connectedness of viruses in brine shrimp is still very limited.A total of 143 batches of brine shrimp(belonging to seven species)cysts were collected from six continents including 21 countries and more than 100 geographic locations worldwide during 1977–2019.In total,55 novel RNA viruses were identified,which could be assigned to 18 different viral families and related clades.Eleven viruses were dsRNA viruses,16 were+ssRNA viruses,and 28 were−ssRNA viruses.Phylogenetic analyses of the RNA-directed RNA polymerase(RdRp)showed that brine shrimp viruses were often grouped with viruses isolated from other invertebrates and fungi.Remarkably,most brine shrimp viruses were related to those from different hosts that might feed on brine shrimp or share the same ecological niche.A notable case was the novel brine shrimp noda-like virus 3,which shared 79.25%(RdRp)and 63.88%(capsid proteins)amino acid identity with covert mortality nodavirus(CMNV)that may cause losses in aquaculture.In addition,both virome composition and phylogenetic analyses revealed global connectedness in certain brine shrimp viruses,particularly among Asia and Northern America.This highlights the incredible species diversity of viruses in these ancient species and provides essential data for the prevalence of RNA viruses in the global aquaculture industry.More broadly,these findings provide novel insights into the previously unrecognized RNA virosphere in hypersaline ecosystems worldwide and demonstrate that human activity might have driven the global connectedness of brine shrimp viruses.展开更多
In this paper, we study the connectedness of the invariant sets of a graph-directed iterated function system(IFS). For a graph-directed IFS with N states, we construct N graphs. We prove that all the invariant sets ...In this paper, we study the connectedness of the invariant sets of a graph-directed iterated function system(IFS). For a graph-directed IFS with N states, we construct N graphs. We prove that all the invariant sets are connected, if and only if all the N graphs are connected; in this case, the invariant sets are all locally connected and path connected. Our result extends the results on the connectedness of the self-similar sets.展开更多
This study investigates resilient platoon control for constrained intelligent and connected vehicles(ICVs)against F-local Byzantine attacks.We introduce a resilient distributed model-predictive platooning control fram...This study investigates resilient platoon control for constrained intelligent and connected vehicles(ICVs)against F-local Byzantine attacks.We introduce a resilient distributed model-predictive platooning control framework for such ICVs.This framework seamlessly integrates the predesigned optimal control with distributed model predictive control(DMPC)optimization and introduces a unique distributed attack detector to ensure the reliability of the transmitted information among vehicles.Notably,our strategy uses previously broadcasted information and a specialized convex set,termed the“resilience set”,to identify unreliable data.This approach significantly eases graph robustness prerequisites,requiring only an(F+1)-robust graph,in contrast to the established mean sequence reduced algorithms,which require a minimum(2F+1)-robust graph.Additionally,we introduce a verification algorithm to restore trust in vehicles under minor attacks,further reducing communication network robustness.Our analysis demonstrates the recursive feasibility of the DMPC optimization.Furthermore,the proposed method achieves exceptional control performance by minimizing the discrepancies between the DMPC control inputs and predesigned platoon control inputs,while ensuring constraint compliance and cybersecurity.Simulation results verify the effectiveness of our theoretical findings.展开更多
An important and practical pattern of industrial symbiosis is rapidly developing: eco-industrial parks. In this study, we used social network analysis to study the network connectedness (i.e., the proportion of the ...An important and practical pattern of industrial symbiosis is rapidly developing: eco-industrial parks. In this study, we used social network analysis to study the network connectedness (i.e., the proportion of the theoretical number of connections that had been achieved) and related attributes of these hybrid ecological and industrial symbiotic systems. This approach provided insights into details of the network's interior and analyzed the overall degree of connectedness and the relationships among the nodes within the network. We then characterized the structural attributes of the network and subnetwork nodes at two levels (core and periphery), thereby providing insights into the operational problems within each eco-industrial park. We chose ten typical eco-industrial parks in China and around the world and compared the degree of network connectedness of these systems that resulted from exchanges of products, byproducts, and wastes. By analyzing the density and nodal degree, we determined the relative power and status of the nodes in these networks, as well as other structural attributes such as the core-periphery structure and the degree of sub-network connectedness. The results reveal the operational problems created by the structure of the industrial networks and provide a basis for improving the degree of completeness, thereby increasing their potential for sustainable development and enriching the methods available for the study of industrial symbiosis.展开更多
We examine the relationship between return and volatility of the stock markets and macroeconomic fundamentals for the G-7 countries by using monthly data ranging from July 1985 to June 2015. To meet this end, we apply...We examine the relationship between return and volatility of the stock markets and macroeconomic fundamentals for the G-7 countries by using monthly data ranging from July 1985 to June 2015. To meet this end, we apply the spillover index approach based on the generalized VAR framework developed by Diebold and Yilmaz (2012, 2014). The empirical analysis shows strong interactions between the returns and volatilities of the G-7 stock markets and the considered set of corresponding macroeconomic factors including industrial production, money supply, interest rates, inflation, oil prices and exchange rates. The return and volatility spillover transmission/reception dynamics of the relationships between these stock markets and the macroeconomic fundamentals have changed after the global financial crisis of 2008. Our findings provide useful insights for investors and policy makers concerned with the unprecedented swings in the stock markets of G-7 countries.展开更多
文摘<strong>Background: </strong>Campus connectedness is a kind of social connectedness that determines the students’ perception of their belonging to the other populace of the campus that includes students, teachers, administrators, and other staff. Campus connectedness plays a significant role in determining stress, anxiety, and depression among students. The purpose of the study was to examine the relationship of campus connectedness to stress, anxiety, and depression among nursing students. <strong>Methods:</strong> This cross-sectional analytical study was conducted among 680 undergraduate nursing students from nine nursing colleges affiliated with a university in Kathmandu Valley. Data were collected from June 1, 2018, through July 10, 2018. Depression, Anxiety, Stress Scale and Campus Connectedness Scale were used to collect data. The data were analyzed using Statistical Package for Social Sciences version 23. A one-way multivariate analysis of variance (MANOVA) test was used to examine the relationship of campus connectedness to stress, anxiety, and depression. Discriminant analysis was done as a follow-up procedure to MANOVA. <strong>Results: </strong>Students had moderate to extremely severe levels of depression (51.7%), anxiety (72.9%) and stress (47%). High campus connectedness score was observed (M = 62.42;SD = 9.79). Statistically significant differences were found among the levels of campus connectedness on the outcome variables, Wilks’ lambda (<em>λ</em>) = 0.90, <em>F</em>(3, 676) = 24.56, <em>p</em> < 0.001. Depression demonstrated the strongest relationship with the discriminant function. <strong>Conclusions: </strong>There was a significant relationship of campus connectedness to stress, anxiety, and depression. Despite the high level of campus connectedness, students had moderate to severe levels of stress, anxiety, and depression. The campus adminstration must take measures and efforts to provide conducive environment and counseling services for the wellbeing of their students.
基金supported by Natural Science Foundation of Guangdong Province of China(990732)Science and Technology Research Foundation of Guangdong Province(2KM03508N)+1 种基金Major Scientific Research Project of Guangdong Province(2003A2010601)21 Century Talented Person Foundation of Educational Ministry,China
文摘Pig breeding is generally conducted among many herds, so EBV comparisons across populationsare necessary. Genetic connectedness is required for reliable between-farm animal EBV comparisons.Five quantitative overall connectedness measures among populations have been proposed so far,coefficient of connectedness(γ*), coefficient of determination (CD) and overall indices ofprecision, connectedness rating, number of direct genetic links between subpopulations due tocommon sires and dams (GLt), and average genetic covariance (AGC) are reviewed and theirproperties are discussed in this paper. It is recommended to use AGC at present for measuringgenetic connectedness between herds.
文摘This study investigates the dynamic connectedness between stock indices and the effect of economic policy uncertainty(EPU)in eight countries where COVID-19 was most widespread(China,Italy,France,Germany,Spain,Russia,the US,and the UK)by implementing the time-varying VAR(TVP-VAR)model for daily data over the period spanning from 01/01/2015 to 05/18/2020.Results showed that stock markets were highly connected during the entire period,but the dynamic spillovers reached unprecedented heights during the COVID-19 pandemic in the first quarter of 2020.Moreover,we found that the European stock markets(except Italy)transmitted more spillovers to all other stock markets than they received,primarily during the COVID-19 outbreak.Further analysis using a nonlinear framework showed that the dynamic connectedness was more pronounced for negative than for positive returns.Also,findings showed that the direction of the EPU effect on net connectedness changed during the pandemic onset,indicating that information spillovers from a given market may signal either good or bad news for other markets,depending on the prevailing economic situation.These results have important implications for individual investors,portfolio managers,policymakers,investment banks,and central banks.
文摘Analyzing comovements and connectedness is critical for providing significant implications for crypto-portfolio risk management.However,most existing research focuses on the lower-order moment nexus(i.e.the return and volatility interactions).For the first time,this study investigates the higher-order moment comovements and risk connectedness among cryptocurrencies before and during the COVID-19 pandemic in both the time and frequency domains.We combine the realized moment measures and wavelet coherence,and the newly proposed time-varying parameter vector autoregression-based frequency connectedness approach(Chatziantoniou et al.in Integration and risk transmission in the market for crude oil a time-varying parameter frequency connectedness approach.Technical report,University of Pretoria,Department of Economics,2021)using intraday high-frequency data.The empirical results demonstrate that the comovement of realized volatility between BTC and other cryp-tocurrencies is stronger than that of the realized skewness,realized kurtosis,and signed jump variation.The comovements among cryptocurrencies are both time-dependent and frequency-dependent.Besides the volatility spillovers,the risk spillovers of high-order moments and jumps are also significant,although their magnitudes vary with moments,making them moment-dependent as well and are lower than volatility connectedness.Frequency connectedness demonstrates that the risk connectedness is mainly transmitted in the short term(1–7 days).Furthermore,the total dynamic connectedness of all realized moments is time-varying and has been significantly affected by the outbreak of the COVID-19 pandemic.Several practical implications are drawn for crypto investors,portfolio managers,regulators,and policymakers in optimizing their investment and risk management tactics.
文摘A fast interactive segmentation algorithm of image-sequences based on relative fuzzy connectedness is presented. In comparison with the original algorithm, the proposed one, with the same accuracy, accelerates the segmentation speed by three times for single image. Meanwhile, this fast segmentation algorithm is extended from single object to multiple objects and from single-image to image-sequences. Thus the segmentation of multiple objects from complex hackground and batch segmentation of image-sequences can be achieved. In addition, a post-processing scheme is incorporated in this algorithm, which extracts smooth edge with one-pixel-width for each segmented object. The experimental results illustrate that the proposed algorithm can obtain the object regions of interest from medical image or image-sequences as well as man-made images quickly and reliably with only a little interaction.
文摘Two pig populations were simulated with Monte Carlo method; each consisted of 5 boars and 50 sows per generation. Genetic connectedness between herds was established by randomly selecting 1 or 2 boars from one population to mate sows of the other population. Breeding pigs were selected within populations according to animal model BLUP. The benefits of genetic connectedness between herds were examined. The results showed that, the average coefficients of inbreeding decreased, while the cumulative selection responses of populations increased, and the higher response occurred randomly in the two populations at generation 5 with the increase of the genetic connectedness between herds. Selection response was affected by genetic connectedness and trait heritability, the lower heritability and higher connectedness, the better selection results. When the number of exchanged litters between populations per generation was 6 litters, the selection results reached a reflection point; if the number of exchanged litters between populations increased further from this point, neither the increase of the cumulative selection responses nor the decrease of coefficients of inbreeding was significant.
基金Foundation item: Supported by the National Natural Science Foundation of China(70071026)
文摘This paper deals with the connectedness of the cone-efficient solution set for vector optimization in locally convex Hausdorff topological vector spaces. The connectedness of the cone-efficient solution set is proved for multiobjective programming defined by a continuous one-to-one cone-quasiconvex mapping on a compact convex set of alternatives. During the proof, the generalized saddle theorem plays a key role.
基金support of Science Foundation Ireland under Grant Number 16/SPP/3347.
文摘We examine the dynamics of liquidity connectedness in the cryptocurrency market.We use the connectedness models of Diebold and Yilmaz(Int J Forecast 28(1):57–66,2012)and Baruník and Křehlík(J Financ Econom 16(2):271–296,2018)on a sample of six major cryptocurrencies,namely,Bitcoin(BTC),Litecoin(LTC),Ethereum(ETH),Ripple(XRP),Monero(XMR),and Dash.Our static analysis reveals a moderate liquidity connectedness among our sample cryptocurrencies,whereas BTC and LTC play a significant role in connectedness magnitude.A distinct liquidity cluster is observed for BTC,LTC,and XRP,and ETH,XMR,and Dash also form another distinct liquidity cluster.The frequency domain analysis reveals that liquidity connectedness is more pronounced in the short-run time horizon than the medium-and long-run time horizons.In the short run,BTC,LTC,and XRP are the leading contributor to liquidity shocks,whereas,in the long run,ETH assumes this role.Compared with the medium term,a tight liquidity clustering is found in the short and long terms.The time-varying analysis indicates that liquidity connectedness in the cryptocurrency market increases over time,pointing to the possible effect of rising demand and higher acceptability for this unique asset.Furthermore,more pronounced liquidity connectedness patterns are observed over the short and long run,reinforcing that liquidity connectedness in the cryptocurrency market is a phenomenon dependent on the time–frequency connectedness.
文摘Estimating genetic connectedness among herds is important for the accuracy of dairy cattle genetic evaluation. When selecting between animals raised in different herds, the accuracy of their genetic evaluations can be influenced by the degree of connectedness among these herds. In this study, two methods were used to measure genetic connectedness, CR (genetic connectedness rating ) and GLt (total number of direct genetic links between group), among herds from Beijing, Shanghai, and Tianjin. Genetic connectedness between the herds from Beijing and Tianjin was 23.95%, between Beijing and Shanghai was 17. 10%, and between Shanghai and Tianjin it was 14.28%. Genetic connectedness between herds from Beijing and Tianjin was the highest and that between Shanghai and Tianjin was the lowest. The correlation coefficient for the two methods was 0. 808. Some suggestions for improved genetic evaluation of dairy cattle were also discussed.
文摘“Connectedness” is an essential component of genetic evaluations. The degree of connectedness affects the accuracy of comparing estimated breeding values (EBVs) from one herd or contemporary group to the other. It can be measured through Connectedness Rating (CR) which is based on variances and covariance among the estimates of contemporary group effects. A computing algorithm and a computer program for estimating CR is available. The minimum required level of connectedness depends upon the size of the contemporary groups, the level of accuracy and the residual variance. About 48% CR is required to detect differences between EBVs that are greater than 20% of the standard deviation in the trait, for group sizes of about 100 animals. Higher levels are necessary for smaller group sizes and for more accurate comparisons. Breeders participating in a common genetic evaluation program should therefore exchange their superior genetics and possibly use some common testing facilities for meaningful estimates of breeding values. Maintaining a good connectedness level will make the genetic evaluation program more useful for selection of superior breeding animals and achieving faster rate of genetic progress.
文摘Social connectedness has been identified as a protective factor for a range of health issues however the literature is not conclusive. The high prevalence of hazardous alcohol consumption and mental health problems among university students along with the potential for the university as a setting for health promotion prompted this study. The study aims to explore the association between levels of alcohol consumption, mental health, social connectedness and social identity among university students. Online data were collected from a random sample of university undergraduate students (n = 2506) aged 18 - 24 years old. Outcomes were measured using the Alcohol Use Disorders Identification Test (AUDIT), the Kessler Psychological Distress Scale, Social Connectedness Scale, Social Identity Scale and measures of paid employment and study (hours), and participation in sports and other clubs. The majority of students had consumed alcohol in the last 12 months (87%). Of these students 38% reported to drink at hazardous levels (AUDIT ≥ 8). When all factors were considered: gender, living arrangements, being a domestic student, hours spent at work, participation in university and community sport, higher levels of psychological distress, higher levels of social connectedness, and lower levels of social identity were significant predictors of hazardous alcohol consumption. The finding highlights the need for the inclusion of integrated, multi-strategy health promotion interventions on campus. Further exploration of the associations between social connectedness and social identity as influences of health behaviors will better inform the development of targeted strategies for specific groups.
基金Supported by the National Natural Science Foundation of China(10871121) Supported by the Research Award for Teachers in Nangyang Normal University(nynu200749)
文摘The concepts of connectedness and locally connectedness is introduced for rightside idempotent quantales. Some properties of connected quantale are studied, and then the equivalent characterization of connected quantale is also given.
基金The NSF (10971079) of Chinathe Basic Research Foundation (201001001,201103194) of Jilin University
文摘The connectedness of the invertibles question for arbitrary nest has been reduced to the case of the lower triangular operators with respect to a fixed orthonormal basis en for n 1. For each f ∈ H∞, let Tf be the Toeplitz operator. In this paper we prove that Tf can be connected to the identity through a path in the invertible group of the lower triangular operators if f satisfies certain conditions.
文摘The topological study of connectedness is heavily geometric or visual. Connectedness and connectedness-like properties play an important role in most topological characterization theorems, as well as in the study of obstructions to the extension of functions. In this paper, the behaviour of these properties in the realm of closure spaces is investigated using the class of perfect mappings. A perfect mapping is a type of map under which the image generally inherits the properties of the mapped space. It turns out that the general behaviour of connectedness properties in topological spaces extends to the class of isotone space.
文摘This article presents the results of a study that evaluated VinclesBCN during COVID-19. This digital-based public social service aims to prevent loneliness and isolation in +65-year-old adults living in Barcelona. Through service user(N = 12) and professional(N = 6) interviews and a questionnaire with service users(N = 255), we demonstrate the pivotal role of digital connectedness in transforming VinclesBCN into a lifeline during the pandemic. The analysis revealed the importance of sociability, social support, and, especially, entertainment in coping with pandemic fatigue and facilitating social connectivity and support among users. Users engaged in activities such as sharing images, songs, memes, and daily greetings to provide proximity, sociability, and care among users, whether they belonged to preexisting groups or were newly introduced to the platform. It also facilitated the identification of individuals who needed companionship, comfort, or more specialized support. The findings emphasize the significance of entertainment as a resilience-building strategy during times of uncertainty. Despite the positive impact, not all users equally used the platform. Non-use was strongly associated with being a woman, having a low educational level, having preexisting social relationships, less time of enrolment in the platform, as well as a high perception of loneliness, poor self-reported health, and low mood. The article underscores the need for further research into older adults' digital engagement during crises, its role in building resilience, and advocating for inclusive digital interventions that take into account diverse older adults' needs and experiences in crisis contexts.
基金This work was supported by the National Key Research and Development Program of China(2018YFD0900501)Central Public-interest Scientific Institution Basal Research Fund,YSFRI,CAFS(20603022022005)+6 种基金Shinan District Science and Technology Foundation(Qingdao)(2022-2-027-ZH)Central Public-interest Scientific Institution Basal Research Fund,CAFS(2020TD39)China Agriculture Research System(CARS-48)C.L.was supported by the Youth Innovation Team of Shandong Higher Education Institution(2021KJ064)the National Natural Science Foundation of China(32200004)W.S.was supported by the Academic Promotion Programme of Shandong First Medical University(2019QL006)E.C.H.was funded by a National Medical Health and Research Council(Australia)Investigator Grant(GNT2017197).
文摘Brine shrimp(Artemia)has existed on Earth for 400 million years and has major ecological importance in hypersaline ecosystems.As a crucial live food in aquaculture,brine shrimp cysts have become one of the most important aquatic products traded worldwide.However,our understanding of the biodiversity,prevalence and global connectedness of viruses in brine shrimp is still very limited.A total of 143 batches of brine shrimp(belonging to seven species)cysts were collected from six continents including 21 countries and more than 100 geographic locations worldwide during 1977–2019.In total,55 novel RNA viruses were identified,which could be assigned to 18 different viral families and related clades.Eleven viruses were dsRNA viruses,16 were+ssRNA viruses,and 28 were−ssRNA viruses.Phylogenetic analyses of the RNA-directed RNA polymerase(RdRp)showed that brine shrimp viruses were often grouped with viruses isolated from other invertebrates and fungi.Remarkably,most brine shrimp viruses were related to those from different hosts that might feed on brine shrimp or share the same ecological niche.A notable case was the novel brine shrimp noda-like virus 3,which shared 79.25%(RdRp)and 63.88%(capsid proteins)amino acid identity with covert mortality nodavirus(CMNV)that may cause losses in aquaculture.In addition,both virome composition and phylogenetic analyses revealed global connectedness in certain brine shrimp viruses,particularly among Asia and Northern America.This highlights the incredible species diversity of viruses in these ancient species and provides essential data for the prevalence of RNA viruses in the global aquaculture industry.More broadly,these findings provide novel insights into the previously unrecognized RNA virosphere in hypersaline ecosystems worldwide and demonstrate that human activity might have driven the global connectedness of brine shrimp viruses.
基金Supported by the Teaching Research Project of Hubei Province(2013469)the 12th Five-Year Project of Education Plan of Hubei Province(2014B379)
文摘In this paper, we study the connectedness of the invariant sets of a graph-directed iterated function system(IFS). For a graph-directed IFS with N states, we construct N graphs. We prove that all the invariant sets are connected, if and only if all the N graphs are connected; in this case, the invariant sets are all locally connected and path connected. Our result extends the results on the connectedness of the self-similar sets.
基金the financial support from the Natural Sciences and Engineering Research Council of Canada(NSERC)。
文摘This study investigates resilient platoon control for constrained intelligent and connected vehicles(ICVs)against F-local Byzantine attacks.We introduce a resilient distributed model-predictive platooning control framework for such ICVs.This framework seamlessly integrates the predesigned optimal control with distributed model predictive control(DMPC)optimization and introduces a unique distributed attack detector to ensure the reliability of the transmitted information among vehicles.Notably,our strategy uses previously broadcasted information and a specialized convex set,termed the“resilience set”,to identify unreliable data.This approach significantly eases graph robustness prerequisites,requiring only an(F+1)-robust graph,in contrast to the established mean sequence reduced algorithms,which require a minimum(2F+1)-robust graph.Additionally,we introduce a verification algorithm to restore trust in vehicles under minor attacks,further reducing communication network robustness.Our analysis demonstrates the recursive feasibility of the DMPC optimization.Furthermore,the proposed method achieves exceptional control performance by minimizing the discrepancies between the DMPC control inputs and predesigned platoon control inputs,while ensuring constraint compliance and cybersecurity.Simulation results verify the effectiveness of our theoretical findings.
文摘An important and practical pattern of industrial symbiosis is rapidly developing: eco-industrial parks. In this study, we used social network analysis to study the network connectedness (i.e., the proportion of the theoretical number of connections that had been achieved) and related attributes of these hybrid ecological and industrial symbiotic systems. This approach provided insights into details of the network's interior and analyzed the overall degree of connectedness and the relationships among the nodes within the network. We then characterized the structural attributes of the network and subnetwork nodes at two levels (core and periphery), thereby providing insights into the operational problems within each eco-industrial park. We chose ten typical eco-industrial parks in China and around the world and compared the degree of network connectedness of these systems that resulted from exchanges of products, byproducts, and wastes. By analyzing the density and nodal degree, we determined the relative power and status of the nodes in these networks, as well as other structural attributes such as the core-periphery structure and the degree of sub-network connectedness. The results reveal the operational problems created by the structure of the industrial networks and provide a basis for improving the degree of completeness, thereby increasing their potential for sustainable development and enriching the methods available for the study of industrial symbiosis.
文摘We examine the relationship between return and volatility of the stock markets and macroeconomic fundamentals for the G-7 countries by using monthly data ranging from July 1985 to June 2015. To meet this end, we apply the spillover index approach based on the generalized VAR framework developed by Diebold and Yilmaz (2012, 2014). The empirical analysis shows strong interactions between the returns and volatilities of the G-7 stock markets and the considered set of corresponding macroeconomic factors including industrial production, money supply, interest rates, inflation, oil prices and exchange rates. The return and volatility spillover transmission/reception dynamics of the relationships between these stock markets and the macroeconomic fundamentals have changed after the global financial crisis of 2008. Our findings provide useful insights for investors and policy makers concerned with the unprecedented swings in the stock markets of G-7 countries.