scholarly journals Multi-feature evaluation of financial contagion

2021 ◽  
Author(s):  
Jarosław Duda ◽  
Henryk Gurgul ◽  
Robert Syrek
Keyword(s):  
Correlation Matrix ◽  
Joint Distribution ◽  
Moving Average ◽  
Principal Component ◽  
Financial Contagion ◽  
Feature Evaluation ◽  
Time Period ◽  
Independent Features ◽  
The Garch Model ◽  
Over Time

AbstractFinancial contagion refers to the spread of market turmoils, for example from one country or index to another country or another index. It is standardly assessed by modelling the evolution of the correlation matrix, for example of returns, usually after removing univariate dynamics with the GARCH model. However, significant events like crises visible in one financial market are usually reflected in other financial markets/countries simultaneously in several dimensions, i.e., in general, entire distributions of returns in other markets are affected. These distributions are determined/described by their expected value, variance, skewness, kurtosis and other statistics that determine the shape of the distribution function of returns, which can be based on higher (mixed) moments. These descriptive statistics are not constant over time, and, moreover, they can interreact within the given market and among the markets over time. In this article we propose, and use for the daily values of five indexes (CAC40, DAX30, DJIA, FTSE250 and WIG20) over the time period 2006–2017, a new, simple and computationally inexpensive methodology to automatically extend contagion evaluation from the evolution of the correlation matrix to the evolution of multiple higher mixed moments as well. Specifically, the joint distribution of normalized variables for each pair of indexes is modeled as a polynomial with time evolving coefficients estimated using an exponential moving average. As we can obtain any arbitrary number of evolving mixed moments this way, its dimensionality reduction using PCA (principal component analysis) is also discussed, obtaining a lower number of dominating and relatively independent features, which can each be interpreted through a polynomial that describes the corresponding perturbation of joint distribution. We obtain features that describe the interrelations among stock markets in several dimensions and that provide information about the current stage of crisis and the strength of the contagion process.

scholarly journals Different Blood Metabolomics Profiles in Infants Consuming a Meat- or Dairy-Based Complementary Diet

Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 388
Author(s):  
Minghua Tang ◽  
Nicholas E. Weaver ◽  
Lillian M. Berman ◽  
Laura D. Brown ◽  
Audrey E. Hendricks ◽  
...  
Keyword(s):  
Amino Acids ◽  
Dietary Intervention ◽  
Principal Component ◽  
Essential Amino Acids ◽  
Infant Growth ◽  
Serum Samples ◽  
Z Scores ◽  
Protein Rich ◽  
Over Time ◽  
Complementary Diet

Background: Research is limited in evaluating the mechanisms responsible for infant growth in response to different protein-rich foods; Methods: Targeted and untargeted metabolomics analysis were conducted on serum samples collected from an infant controlled-feeding trial that participants consumed a meat- vs. dairy-based complementary diet from 5 to 12 months of age, and followed up at 24 months. Results: Isoleucine, valine, phenylalanine increased and threonine decreased over time among all participants; Although none of the individual essential amino acids had a significant impact on changes in growth Z scores from 5 to 12 months, principal component heavily weighted by BCAAs (leucine, isoleucine, valine) and phenylalanine had a positive association with changes in length-for-age Z score from 5 to 12 months. Concentrations of acylcarnitine-C4, acylcarnitine-C5 and acylcarnitine-C5:1 significantly increased over time with the dietary intervention, but none of the acylcarnitines were associated with infant growth Z scores. Quantitative trimethylamine N-oxide increased in the meat group from 5 to 12 months; Conclusions: Our findings suggest that increasing total protein intake by providing protein-rich complementary foods was associated with increased concentrations of certain essential amino acids and short-chain acyl-carnitines. The sources of protein-rich foods (e.g., meat vs. dairy) did not appear to differentially impact serum metabolites, and comprehensive mechanistic investigations are needed to identify other contributors or mediators of the diet-induced infant growth trajectories.

Changes in survival characteristics ofDiplostomum spathaceumcercariae emerged from cadmium-exposedLymnaea stagnalis

2005 ◽  
Vol 79 (1) ◽  
pp. 55-59 ◽  
Author(s):  
N.J. Morley ◽  
M. Crane ◽  
J.W. Lewis
Keyword(s):  
Life Span ◽  
Lymnaea Stagnalis ◽  
Control Population ◽  
Survival Period ◽  
Parasite Transmission ◽  
Tail Loss ◽  
Diplostomum Spathaceum ◽  
Time Period ◽  
Potential Indicator ◽  
Over Time

AbstractThe effect of exposingLymnaea stagnalis(Gastropoda: Pulmonata), infected withDiplostomum spathaceum(Trematoda: Diplostomatidae), to 100 μg l−1cadmium for 7 days on survival characteristics (survival, tail loss, decaudized cercarial life-span) of emerged cercariae was investigated. Exposure ofL. stagnalisto cadmium resulted in significantly increasedD. spathaceumcercarial survival and an inhibited tail loss compared to controls. The normal parallel relationship which exists over time between decreasing cercarial survival and increasing tail loss in controls was changed in cercariae from cadmium-exposed hosts with an increased proportion of cercarial deaths occurring without tail loss. The decaudized cercarial life-span over the survival period of the cercarial population did not significantly change. However comparisons between individuals decaudized during the initial 24 h time period with those which were decaudized during the final period of cercarial survival showed a significantly altered life span which did not occur in the control population. As a potential indicator of penetration ‘fitness’ comparisons were also undertaken between control and exposed cercariae decaudized during the initial 24 h time period, which revealed that the decaudized cercarial life-span from the exposed hosts was significantly different from controls. This may have important implications for the ability of cercariae to migrate through the tissues of their target host. The importance and relevance of these results to parasite transmission are discussed.

scholarly journals Faculty Publishing Productivity: Comparisons over Time

2006 ◽  
Vol 67 (3) ◽  
pp. 230-239 ◽  
Author(s):  
John M. Budd
Keyword(s):  
Academic Librarians ◽  
Tenure Track ◽  
Data Set ◽  
Part Time Faculty ◽  
Time Period ◽  
Rate Of Increase ◽  
Part Time ◽  
Per Capita ◽  
Time Faculty ◽  
Over Time

Concerns about higher education abound, and these include concerns about productivity. The present study extends two previous examinations of faculty publishing productivity covering the years 1991 to 1993 and 1995 to 1997. Both members of ARL and a group of institutions included in ACRL’s data set are included. For both groups there are some increases in mean total numbers of publications, although the rate of increase has decreased since the second time period. Per capita rates of publication demonstrate an even flatter pattern. In recent years, there have been some changes in the dynamics of universities’ faculties; there are more part-time faculty and more faculty who are not on the tenure track. These factors, coupled with the publishing data, point to activities that all academic librarians should be aware of.

scholarly journals Creating relationship continuity across projects in the construction industry

IMP Journal ◽  
2017 ◽  
Vol 11 (2) ◽  
pp. 207-229 ◽  
Author(s):  
Malena Ingemansson Havenvid ◽  
Elsebeth Holmen ◽  
Åse Linné ◽  
Ann-Charlott Pedersen
Keyword(s):  
Construction Industry ◽  
Empirical Studies ◽  
Mutual Orientation ◽  
Content Type ◽  
Construction Firms ◽  
Relationship Continuity ◽  
Time Period ◽  
Strategy Types ◽  
The Relationship ◽  
Over Time

Purpose The purpose of this paper is to investigate the relationship continuity across projects among actors in the construction industry, and to discuss why and how such continuity takes place. Design/methodology/approach The authors draw on the results from four in-depth case studies illustrating different strategies for pursuing relationship continuity. The results are analysed and discussed in light of the oft-mentioned strategies suggested by Mintzberg (1987): emergent, deliberate and deliberately emergent strategies. Furthermore, the ARA-model is used to discuss why the relationship continuity strategies are pursued, and which factors might enable and constrain the relationship continuity. Findings The main findings are twofold. First, the authors found that the strategy applied for pursuing relationship continuity may, in one-time period, contain one type of strategy or a mix of strategy types. Second, the type of strategy may evolve over time, from one type of strategy being more pronounced in one period, to other strategies being more pronounced in later periods. The strategies applied by construction firms and their counterparts can thus contain elements of emergent, deliberate and deliberately emergent strategies, in varying degrees over time. It is also shown that the strategies of the involved actors co-evolve as a result of interaction. Also, the main reasons for pursuing continuity appear to lie in the re-use and development of important resources and activities across projects to create efficiency and the possibility to develop mutual orientation, commitment and trust over time, and thus reduce uncertainty. Research limitations/implications Further empirical studies are needed to support the findings. For managers, the main implication is that relationship continuity can arise as part of an emerging interaction pattern between firms or as part of a planned strategy, but that elements of both might be needed to sustain it. Originality/value The authors combine Mintzberg’s strategy concepts with the ARA-model to bring new light to the widely debated issue of discontinuity and fragmentation in the construction industry.

scholarly journals Visualizing Belief in Meritocracy, 1930–2010

2018 ◽  
Vol 4 ◽  
pp. 237802311881180 ◽  
Author(s):  
Jonathan J. B. Mijs
Keyword(s):  
Survey Data ◽  
Representative Sample ◽  
Western World ◽  
Birth Cohorts ◽  
Popular Belief ◽  
Time Period ◽  
Level Data ◽  
Two Measures ◽  
Time Periods ◽  
Over Time

In this figure I describe the long trend in popular belief in meritocracy across the Western world between 1930 and 2010. Studying trends in attitudes is limited by the paucity of survey data that can be compared across countries and over time. Here, I show how to complement survey waves with cohort-level data. Repeated surveys draw on a representative sample of the population to describe the typical beliefs held by citizens in a given country and period. Leveraging the fact that citizens surveyed in a given year were born in different time-periods allows for a comparison of beliefs across birth cohorts. The latter overlaps with the former, but considerably extends the time period covered by the data. Taken together, the two measures give a “triangulated” longitudinal record of popular belief in meritocracy. I find that in most countries, popular belief in meritocracy is (much) stronger for more recent periods and cohorts.

scholarly journals Regional background O<sub>3</sub> and NO<sub>x</sub> in the Houston-Galveston- Brazoria (TX) region: A decadal-scale perspective

2016 ◽  
Author(s):  
Loredana G. Suciu ◽  
Robert J. Griffin ◽  
Caroline A. Masiello
Keyword(s):  
Spatial Scales ◽  
Lower Troposphere ◽  
Principal Component ◽  
Ground Level ◽  
Ambient Air ◽  
Regional Background ◽  
Time Period ◽  
Decadal Scale ◽  
Many Sources ◽  
Local Emissions

Abstract. Ozone (O3) in the lower troposphere is harmful to people and plants, particularly during summer, when photochemistry is the most active and higher temperatures favor local chemistry. Because of its dependence on the volatile organic compounds (VOCs) to nitrogen oxides (NOx) ratio, ground-level O3 is difficult to control locally, where many sources of these precursors contribute to its mixing ratio. In addition to local emissions, chemistry and transport, larger-scale factors also contribute to local O3 and NOx. These additional contributions (often referred to as "regional background") are not well quantified within the Houston-Galveston-Brazoria (HGB) region, impeding more efficient controls on precursor emissions to achieve compliance with the National Ambient Air Quality Standards for O3. In this study, we estimate regional background O3 and NOx in the HGB region and quantify their decadal-scale trends. We use four different approaches based on principal component analysis (PCA) to quantify background O3 and NOx. Three of these approaches consist of independent PCA on both O3 and NOx for both 1-h and 8-h levels to compare our results with previous studies and to highlight the effect of both temporal and spatial scales. In the fourth approach, we co-varied O3, NOx and meteorology. Our results show that the estimation of regional background O3 has less inherent uncertainty when it was constrained by NOx and meteorology, yielding a statistically significant temporal trend of −0.69 ± 0.27 ppb y−1. Likewise, the estimation of regional background NOx trend constrained by O3 and meteorology was −0.04 ± 0.02 ppb y−1. Our best estimates of 17-y average of season-scale background O3 and NOx were 46.72 ± 2.08 ppb and 6.80 ± 0.13 ppb, respectively. Regional background O3 and NOx both have declined over time in the HGB region. This decline is likely caused by a combination of state of Texas controls on precursor emissions since 2007 and the increase in frequency of flow from the Gulf of Mexico over the same time period.

Mixture copulas and insurance applications

2018 ◽  
Vol 12 (2) ◽  
pp. 391-411
Author(s):  
Maissa Tamraz
Keyword(s):  
Joint Distribution ◽  
Stable Distribution ◽  
Random Variable ◽  
Fixed Time ◽  
Collective Model ◽  
Data Sets ◽  
New Model ◽  
Time Period ◽  
Insurance Data ◽  
Dependence Property

AbstractIn the classical collective model over a fixed time period of two insurance portfolios, we are interested, in this contribution, in the models that relate to the joint distributionFof the largest claim amounts observed in both insurance portfolios. Specifically, we consider the tractable model where the claim counting random variableNfollows a discrete-stable distribution with parameters (α,λ). We investigate the dependence property ofFwith respect to both parametersαandλ. Furthermore, we present several applications of the new model to concrete insurance data sets and assess the fit of our new model with respect to other models already considered in some recent contributions. We can see that our model performs well with respect to most data sets.

scholarly journals Neglecting Decline: Remembered and Predicted Personal Development Diverge from Actual Longitudinal Change.

2019 ◽  
Author(s):  
Sarah Molouki ◽  
Daniel Bartels ◽  
Oleg Urminsky
Keyword(s):  
Longitudinal Study ◽  
Personal Development ◽  
Absolute Magnitude ◽  
Longitudinal Change ◽  
Personal Change ◽  
Future Change ◽  
Change Over Time ◽  
Time Period ◽  
One Year ◽  
Over Time

A one-year longitudinal study was conducted to investigate the accuracy of people’s assessmentsof their own personal change over time. We compared people’s predicted, actual, and recalledchange in their personality, values, and preferences over this time period. On average,participants underestimated the absolute magnitude of their personal change, yet simultaneouslyoverestimated their net improvement, in both prediction and recall. This effect was due to anasymmetry whereby people selectively neglected negative changes, especially prospectively.Although participants in our sample both improved and declined over the year, they were morelikely to remember past improvements than declines, and made nearly uniformly positivepredictions of future change. We discuss how the current findings reconcile researchdemonstrating expectations of personal improvement (e.g., Wilson &amp; Ross, 2001; Kanten &amp;Teigen, 2008) with other research that suggests people overpredict their personal stability(Quoidbach, Gilbert, &amp; Wilson, 2013).

scholarly journals Geographic disparities and socio-demographic predictors of pertussis risk in Florida

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11902
Author(s):  
Corinne B. Tandy ◽  
Agricola Odoi
Keyword(s):  
Resource Allocation ◽  
High Risk ◽  
Geographic Distribution ◽  
Temporal Changes ◽  
County Level ◽  
Spatial Clusters ◽  
Geographic Disparities ◽  
Demographic Predictors ◽  
Time Period ◽  
Over Time

Background Pertussis is a toxin-mediated respiratory illness caused by Bordetella pertussis that can result in severe complications and death, particularly in infants. Between 2008 and 2011, children less than 3 months old accounted for 83% of the pertussis deaths in the United States. Understanding the geographic disparities in the distribution of pertussis risk and identifying high risk geographic areas is necessary for guiding resource allocation and public health control strategies. Therefore, this study investigated geographic disparities and temporal changes in pertussis risk in Florida from 2010 to 2018. It also investigated socioeconomic and demographic predictors of the identified disparities. Methods Pertussis data covering the time period 2010–2018 were obtained from Florida HealthCHARTS web interface. Spatial patterns and temporal changes in geographic distribution of pertussis risk were assessed using county-level choropleth maps for the time periods 2010–2012, 2013–2015, 2016–2018 and 2010–2018. Tango’s flexible spatial scan statistics were used to identify high-risk spatial clusters which were displayed in maps. Ordinary least squares (OLS) regression was used to identify significant predictors of county-level risk. Residuals of the OLS model were assessed for model assumptions including spatial autocorrelation. Results County-level pertussis risk varied from 0 to 116.31 cases per 100,000 people during the study period. A total of 11 significant (p < 0.05) spatial clusters were identified with risk ratios ranging from 1.5 to 5.8. Geographic distribution remained relatively consistent over time with areas of high risk persisting in the western panhandle, northeastern coast, and along the western coast. Although county level pertussis risks generally increased from 2010–2012 to 2013–2015, risk tended to be lower during the 2016–2018 time period. Significant predictors of county-level pertussis risk were rurality, percentage of females, and median income. Counties with high pertussis risk tended to be rural (p = 0.021), those with high median incomes (p = 0.039), and those with high percentages of females (p < 0.001). Conclusion There is evidence that geographic disparities exist and have persisted over time in Florida. This study highlights the application and importance of Geographic Information Systems (GIS) technology and spatial statistical/epidemiological tools in identifying areas of highest disease risk so as to guide resource allocation to reduce health disparities and improve health for all.

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