Development and psychometric validation of Internet Gaming Disorder Scale-Short-Form (IGDS9-SF) in a Brazilian sample

Objectives: The aim of this study was to develop and examine the psychometric properties of the IGDS9-SF in a sample of Brazilian gamers and to find the best cut-off point for this instrument using a normative and clinically diagnosed sample of gamers. Methods: A total of 610 participants were recruited to the present study. Construct validity was assessed through Exploratory and Confirmatory Factor Analysis (EFA, CFA). Criterion-related validity was established through the associations with Game Addiction Scale (GAS) and weekly gameplay. Reliability analysis was performed using the Cronbach’s alpha () as the indicator of internal consistency. A cut-off point was estimated using the Receiver Operating Characteristics Curve (ROC curve) where the results of a clinical assessment was used as the gold standard. Results: EFA and CFA findings confirmed the single-factor structure of the IGDS9-SF. Positive correlations indicated adequate criterion-related validity, and the scale was shown to be reliable (). Finally, the optimal cut-off point for risky gaming was found to be points and for diagnosis to be points. Conclusions: This study provides validity and reliability evidence for the use of the Brazilian version of the IGDS9-SF in the assessment of Internet Gaming Disorder, further supporting its usefulness as a robust psychometric tool that can be employed in clinical and research settings in Brazil

Metapopulation consequences of site fidelity for colonially breeding mammals and birds

<p>1: Many far-ranging bird and mammal species aggregate in colonies to breed, and most individuals remain faithful to one colony. Here, we use modelling to explore the consequences of this site fidelity for the metapopulation dynamics of such species.</p> <p>2: We develop a spatially explicit model of the annual transfer process between colonies. We apply it to different spatial arrangements of 20 identical colonies and thus demonstrate that connectivity alone can, in the short term, give rise to heterogeneity in colony size.</p> <p>3:We place the annual transfer model within a state-structured population model and examine the consequences of local and global density dependence for long-term dynamics. For each scenario, we investigate the implications of the strength of site fidelity, the cost of migration and the population's intrinsic growth rate.</p> <p>4: Our results suggest that, under local density dependence, site fidelity slows down the colonization process and can temporarily trap the entire population in a subset of the available potential colonies. When site fidelity is strong, the metapopulation follows a step-like trajectory. Population growth occurs only rarely because individuals must overcome their site-fidelity to found new colonies. Even though this effect is temporary, it renders the entire metapopulation vulnerable to rare catastrophic collapses.</p> <p>5: Under global density dependence, site fidelity imposes competition between colonies for the limiting resource. Stochastic events lead to the dominance of certain colonies and the temporary extinction of others. If site fidelity is strong, it can permanently prevent the metapopulation from occupying all available potential colonies.</p> <p>6: We conclude that, irrespective of the mechanism of population regulation, colonially breeding species that show strong site fidelity are likely to occupy only a portion of the breeding habitat available to them.</p&gt

Eogenetic Karst from the Perspective of an Equivalent Porous Medium

The porosity of young limestones experiencing meteoric diagenesis in the vicinity of their deposition (eogenetic karst) is mainly a double porosity consisting of touching-vug channels and preferred passageways lacing through a matrix of interparticle porosity. In contrast, the porosity of limestones experiencing subaerial erosion following burial diagenesis and uplift (telogenetic karst) is mainly a double porosity consisting of conduits within a network of fractures. The stark contrast between these two kinds of karst is illustrated by their position on a graph showing the hydraulic characteristics of an equivalent porous medium consisting of straight, cylindrical tubes (n-D space, where n is porosity,D is the diameter of the tubes, and logn is plotted against logD). Studies of the hydrology of small carbonate islands show that large-scale, horizontal hydraulic conductivity (K) increases by orders of magnitude during the evolution of eogenetic karst. Earlier petrologic studies have shown there is little if any change in the total porosity of the limestone during eogenetic diagenesis. The limestone of eogenetic karst, therefore, tracks horizontally inn-D space. In contrast, the path from initial sedimentary material to telogenetic karst comprises a descent on the graph with reduction ofn during burial diagenesis, then a sideways shift with increasingD due to opening of fractures during uplift and exposure, and finally an increase inD andn during development of the conduits along the fractures. Eogenetic caves are mainly limited to boundaries between geologic units and hydrologic zones: stream caves at the contact between carbonates and underlying impermeable rocks (and collapse-origin caves derived therefrom); vertical caves along platform-margin fractures; epikarst; phreatic pockets (banana holes) along the water table; and flank margin caves that form as mixing chambers at the coastal freshwater-saltwater “interface”. In contrast, the caverns of telogenetic karst are part of a system of interconnected conduits that drain an entire region. The eogenetic caves of small carbonate islands are, for the most part, not significantly involved in the drainage of the island