116 research outputs found

    Calcareous Bio-Concretions in the Northern Adriatic Sea: Habitat Types, Environmental Factors that Influence Habitat Distributions, and Predictive Modeling

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    Habitat classifications provide guidelines for mapping and comparing marine resources across geographic regions. Calcareous bio-concretions and their associated biota have not been exhaustively categorized. Furthermore, for management and conservation purposes, species and habitat mapping is critical. Recently, several developments have occurred in the field of predictive habitat modeling, and multiple methods are available. In this study, we defined the habitats constituting northern Adriatic biogenic reefs and created a predictive habitat distribution model. We used an updated dataset of the epibenthic assemblages to define the habitats, which we verified using the fuzzy k-means (FKM) clustering method. Redundancy analysis was employed to model the relationships between the environmental descriptors and the FKM membership grades. Predictive modelling was carried out to map habitats across the basin. Habitat A (opportunistic macroalgae, encrusting Porifera, bioeroders) characterizes reefs closest to the coastline, which are affected by coastal currents and river inputs. Habitat B is distinguished by massive Porifera, erect Tunicata, and noncalcareous encrusting algae (Peyssonnelia spp.). Habitat C (non-articulated coralline, Polycitor adriaticus) is predicted in deeper areas. The onshore-offshore gradient explains the variability of the assemblages because of the influence of coastal freshwater, which is the main driver of nutrient dynamics. This model supports the interpretation of Habitat A and C as the extremes of a gradient that characterizes the epibenthic assemblages, while Habitat B demonstrates intermediate characteristics. Areas of transition are a natural feature of the marine environment and may include a mixture of habitats and species. The habitats proposed are easy to identify in the field, are related to different environmental features, and may be suitable for application in studies focused on other geographic areas. The habitat model outputs provide insight into the environmental drivers that control the distribution of the habitat and can be used to guide future research efforts and cost-effective management and conservation plans

    Exploring spatio-temporal changes in the demersal and benthopelagic assemblages of the northwestern Ionian Sea (central Mediterranean Sea)

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    An exploration of the structure of demersal and benthopelagic assemblages in the north-western Ionian Sea was carried out by means of a set of statistical analyses. Self-organising map (SOM) and clustering methods applied to 183 taxa and their biomass (kg km-2) provided the classification of 1288 experimental hauls exploring the bathymetric range 10-800 m from 1995 to 2012. Six clusters were identified according to their similarities in species abundances (biomass), confirming the depth gradient as the main structuring agent. In order to identify key representative species in each cluster, the taxa were ranked by means of an indicator value index (IndVal) and the contribution of species to beta diversity (BD). Furthermore, the clusters were described by means of environmental and fishing characteristics. Particular habitat type, distance to canyon and fishing effort segregated the assemblages on the coastal shelf and slope. Temporal differences were detected in 2 bathyal groups, which were most likely affected by the 1990s environmental change in the deepwater circulation known as the Eastern Mediterranean Transient. The overall total BD in the study area was calculated as 0.79, with a temporal decrease observed at a rate of 0.7% yr-1. The approaches used are useful to identify and characterize the species aggregations inside complex faunal assemblages, without a priori assumptions about data distribution. These results can be a starting point for defining functional groups for Mediterranean food web modelling approaches, as well as for identifying indicator species to assess the environmental status in the context of the Marine Strategy Framework Directive

    The Great Separation: Top Earner Segregation at Work in High-Income Countries

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    Analyzing linked employer-employee panel administrative databases, we study the evolving isolation of higher earners from other employees in eleven countries: Canada, Czechia, Denmark, France, Germany, Hungary, Japan, Norway, Spain, South Korea, and Sweden. We find in almost all countries a growing workplace isolation of top earners and dramatically declining exposure of top earners to bottom earners. We compare these trends to segregation based on occupational class, education, age, gender, and nativity, finding that the rise in top earner isolation is much more dramatic and general across countries. We find that residential segregation is also growing, although more slowly than segregation at work, with top earners and bottom earners increasingly living in different distinct municipalities. While work and residential segregation are correlated, statistical modeling suggests that the primary causal effect is from work to residential segregation. These findings open up a future research program on the causes and consequences of top earner segregation.En nous appuyant sur des données administratives longitudinales employeur–employés, nous analysons l’évolution de la ségrégation sociale des salariés à hauts salaires dans onze pays: Allemagne, Canada, Corée du Sud, Danemark, Espagne, France, Hongrie, Japon, Norvège, République tchèque et Suède. Nous constatons dans presque tous les pays une forte augmentation de l’entre soi des salariés bien payés sur le lieu de travail et une diminution spectaculaire de leur exposition aux bas salaires. Nous comparons ces tendances à l’évolution de la ségrégation fondée sur la catégorie sociale, l’éducation, l’âge, le sexe et le statut migratoire, et nous constatons que l’augmentation de l’entre soi des hauts salaires est celle qui est la plus prononcée et la plus générale. Nous montrons que la ségrégation résidentielle se développe aussi, bien que plus lentement que la ségrégation au travail, avec les hauts et les bas salaires vivant de plus en plus dans des municipalités distinctes. Ségrégation au travail et ségrégation résidentielle sont corrélées. Mais nos modèles statistiques suggèrent aussi que la principale relation de causalité va de la ségrégation au travail vers la ségrégation résidentielle. Ces résultats ouvrent la voie à un futur programme de recherche sur les causes et les conséquences de la ségrégation des hauts salaires.1 Introduction 2 From ethnic residential segregation to earnings segregation at work 3 Administrative data for estimating exposure measures 4 A strong increase in earnings segregation at work 5 A robust trend 17 French robustness tests 6 A specific trend 7 The link between work and residential segregation 8 Elements for a research program on the causes and consequences of increasing segregation at work The roots of growing earnings segregation at work The consequences of growing earnings segregation at work Appendices A1 Data sources and sample definition A2 Demonstration of the symmetry of relative exposure gRh = hRg A3 Figure construction A4 French robustness checks Supplementary figures and tables Reference

    Signalling Demand for Foreign Investment: Postsocialist Countries in the Global Bilateral Investment Treaties Network

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    A unique dataset on bilateral investment treaties provides a novel source of evidence on the link between neoliberal globalisation and market transition. We argue that postsocialist countries of Europe and Eurasia, more than other developing regions in the world, signed such treaties to signal demand for foreign investment in the spirit of neoliberalism. We calculated the density of the whole BIT network since its inception in 1959 to 2009, and density and centrality of different regional blocks within it, and found strong support for our argument. Yet, even if bilateral investment treaties are designed to promote foreign direct investment, dynamic panel regression models show that signing them does not automatically translate into foreign direct investment inflows for postsocialist European and Eurasian countries in the 1990–2010 period

    SSR and AFLP based genetic diversity of soybean germplasm differing in photoperiod sensitivity

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    Forty-four soybean genotypes with different photoperiod response were selected after screening of 1000 soybean accessions under artificial condition and were profiled using 40 SSR and 5 AFLP primer pairs. The average polymorphism information content (PIC) for SSR and AFLP marker systems was 0.507 and 0.120, respectively. Clustering of genotypes was done using UPGMA method for SSR and AFLP and correlation was 0.337 and 0.504, respectively. Mantel's correlation coefficients between Jaccard's similarity coefficient and the cophenetic values were fairly high in both the marker systems (SSR = 0.924; AFLP = 0.958) indicating very good fit for the clustering pattern. UPGMA based cluster analysis classified soybean genotypes into four major groups with fairly moderate bootstrap support. These major clusters corresponded with the photoperiod response and place of origin. The results indicate that the photoperiod insensitive genotypes, 11/2/1939 (EC 325097) and MACS 330 would be better choice for broadening the genetic base of soybean for this trait
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