906 research outputs found
On the Evolution of Product Portfolio Coherence of Cooperatives versus Corporations: An Agent-Based Analysis of the Single Origin Constraint
Agent-based methodology is adopted to analyze the relationship between governance structure and the evolution of product portfolio. A corporation and a cooperative are distinguished by the single origin constraint. The single origin constraint entails that the product requiring the inputs of the members of a cooperative will never be divested. It is es-tablished that a concentric diversification strategy results in randomly distributed clusters of related products of the product portfolio of corporations, while the single origin constraint of a cooperative is responsible for pulling all prod-ucts together in one cluster. More general, the centripetal effect of one product with infinite lifetime on portfolio com-position dominates the centrifugal effect of products with finite lifetime, regardless the number of products with finite lifetime
Intersectional Discrimination and Change in Blood Pressure Control among Older Adults: The Health and Retirement Study
BACKGROUND: Associations between multiple forms of discrimination and blood pressure control in older populations remain unestablished. METHODS: Participants were 14582 non-institutionalized individuals (59% women) in the Health and Retirement Study aged at least 51 years (76% Non-Hispanic White, 15% Non-Hispanic Black, 9% Hispanic/Latino). Primary exposures included the mean frequency of discrimination in everyday life, intersectional discrimination (defined as marginalization ascribed to more than one reason), and the sum of discrimination over the lifespan. We assessed whether discrimination was associated with change in measured hypertension status (N=14582) and concurrent medication use among reported hypertensives (N=9086) over four years (2008-2014). RESULTS: There was no association between the frequency of everyday discrimination and change in measured hypertension. Lifetime discrimination was associated with higher odds of hypertension four years later among men (OR: 1.21, 95% CI: 1.08, 1.36) but not women (OR: 0.98, 95% CI: 0.86, 1.13). Only among men, everyday discrimination due at least two reasons was associated with a 1.44 (95% CI: 1.03, 2.01)-fold odds of hypertension than reporting no everyday discrimination; reporting intersectional discrimination was not associated with developing hypertension among women (OR: 0.91, 95% CI: 0.70, 1.20). All three discriminatory measures were inversely related to time-averaged antihypertensive medication use, without apparent gender differences (e.g., OR for everyday discrimination-antihypertensive use associations: 0.85, 95% CI: 0.77, 0.94)). CONCLUSIONS: Gender differences in marginalization may more acutely elevate hypertensive risk among older men than similarly aged women. Experiences of discrimination appear to decrease the likelihood of antihypertensive medication use among older adults overall
Predicting recurrence of depression using cardiac complexity in individuals tapering antidepressants
It is currently unknown whether the complexity and variability of cardiac dynamics predicts future depression and whether within-subject change herein precedes the recurrence of depression. We tested this in an innovative repeated single-subject study in individuals who had a history of depression and were tapering their antidepressants. In 50 individuals, electrocardiogram (ECG) derived Interbeat-interval (IBI) time-series data were collected for 5 min every morning and evening, for 4 months. Usable data were obtained from 14 participants who experienced a transition (i.e., a clinically significant increase in depressive symptoms) and 14 who did not. The mean, standard deviation, Higuchi dimension and multiscale entropy, calculated from IBIs, were examined for time trends. These quantifiers were also averaged over a baseline period and compared between the groups. No consistent trends were observed in any quantifier before increases in depressive symptoms within individuals. The entropy baseline levels significantly differed between the two groups (morning: P value < 0.001, Cohenās d = ā2.185; evening: P value < 0.001, Cohenās d = ā1.797) and predicted the recurrence of depressive symptoms, in the current sample. Moreover, higher mean IBIs and Higuchi dimensions were observed in individuals who experienced transitions. While we found little evidence to support the existence of within- individual warning signals in IBI time-series data preceding an upcoming depressive transition, our results indicate that individuals who taper antidepressants and showed lower entropy of cardiac dynamics exhibited a higher chance of recurrence of depression. Hence, entropy could be a potential digital phenotype for assessing the risk of recurrence of depression in the short term while tapering antidepressants
Vine Signal Extraction - an Application of remote sensing in precision Viticulture
This paper presents a study of precision agriculture in the wine industry. While precision viticulture mostly aims to maximise yields by delivering the right inputs to appropriate places on a farm in the correct doses and at the right time, the objective of this study was rather to assess vine biomass differences. The solution proposed in this paper uses aerial imagery as the primary source of data for vine analysis. The first objective to be achieved by the solution is to automatically identify vineyards blocks, vine rows, and individual vines within rows. This is made possible through a series of enhancements and hierarchical segmentations of the aerial images. The second objective is to determine the correlation of image data with the biophysical data (yield and pruning mass) of each vine. A multispectral aerial image is used to compute vegetation indices, which serve as indicators of biophysical measures. The results of the automatic detection are compared against a test field, to verify both vine location and vegetation index correlation with relevant vine parameters. The advantage of this technique is that it functions in environments where active cover crop growth between vines is evident and where variable vine canopy conditions are present within a vineyard block
Risk Ahead: Actigraphy-Based Early-Warning Signals of Increases in Depressive Symptoms During Antidepressant Discontinuation
Antidepressant discontinuation increases the risk of experiencing depressive symptoms. In a repeated single-subject design, we tested whether transitions in depression were preceded by increases in actigraphy-based critical-slowing-down-based early-warning signals (EWSs; variance, kurtosis, autocorrelation), circadian-rhythm-based indicators, and decreases in mean activity levels. Four months of data from 16 individuals with a transition in depression and nine without a transition in depression were analyzed using a moving-window method. As expected, more participants with a transition showed at least one EWS (50% true positives; 22.2% false positives). Increases in circadian rhythm variables (25.0% true positives vs. 44.4% false positives) and decreases in activity levels (37.5% true positives vs. 44.4% false positives) were more common in participants without a transition. None of the tested risk indicators could confidently predict upcoming transitions in depression, but some evidence was found that critical-slowing-down-based EWSs were more common in participants with a transition
The link between Internet investor relations and information asymmetry
Background:Ā Information asymmetry manifests when one party has more or better information than the other. Information asymmetry is said not only to increase transaction costs and decrease liquidity, but also to diminish the quality of the investment decisions taken by investors, thus weakening the overall functioning of markets.
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Aim and setting:Ā A well-developed Internet investor relations (IIR) strategy, coupled with increased disclosure levels, should theoretically decrease information asymmetry levels. The majority of related studies to date used either an indirect disclosure proxy or involved an examination of the annual report, and have used data from United States or European companies. Empirical studies to date have produced mixed results. The aim of this study was to ascertain whether a relationship exists between the quality of IIR (via corporate websites) and information asymmetry.
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Method:Ā This study used data from Johannesburg Stock Exchange (JSE)-listed companies. Multiple regression analysis was applied with information asymmetry as dependent variable and IIR as one of a set of selected explanatory variables. A self-constructed measurement instrument was used to measure IIR for a sample of 85 companies. Given the inherent difficulty with direct observation of information asymmetry, three different proxies were used to estimate information asymmetry.
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Results:Ā A significant negative association was found between IIR and information asymmetry for all three information asymmetry proxies that were used: bid-ask spread, price impact, and analyst following.
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Conclusion:Ā Empirical support is provided for the notion that companies may potentially benefit from a well-developed IIR strategy through reduced information asymmetry
Predicting recurrence of depression using cardiac complexity in individuals tapering antidepressants
Funding Information: We would like to thank GM Bloem, D Sloohof, G Arts, and E van den Kieboom for their work on (pre-)processing the physiological data. This project has received funding from the European Research Council (ERC) under the European Unionās Horizon 2020 research and innovation program (ERC-CoG-2015; No. 681466 to M Wichers). The Cortrium monitors were kindly provided by the iLab of the Department of Psychiatry of the University Medical Center Groningen (UMCG, http://www.ilab-psychiatry.nl ).Peer reviewe
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