Effects of Set-Size on Switch-Cost

This study investigated how a set-size manipulation (as published in Fitzgibbon, Cragg & Carroll, 2014) could affect switch-cost in a switching-task, and the relation to working memory capacity. A student sample of 29 participants was recruited. Results revealed that decreasing the set-size might facilitate switching. Working memory capacity was negatively correlated with repeating a task (i. e., with not switching), when the set-size was large. The results are relevant to theoretical top-down and bottom-up explanations of switch-cost, and have practical implication for the further use of task-switching paradigms

Surgeon-performed ultrasound and timing of surgery in acute cholecystitis

Introduction: The use of bedside ultrasound has increased, as equipment has become accessible, user friendly, and ultrasound education is expanding in many specialties. The aim of this project was to validate surgeon-performed ultrasound and to optimise the surgical treatment for patients with acute cholecystitis, in particular in planning timing of surgery. Methods: Papers I-III represent prospective clinical studies where patients with gallstones, acute cholecystitis or appendicitis were included. Sensitivity, specificity, accuracy, and predictive values of surgeon-performed ultrasound were calculated for these diagnoses. Radiologist-performed ultrasound was used as reference for the diagnosis of gallstones (Paper I). In acute cholecystitis, internationally accepted criteria for the diagnosis were used as reference, and in appendicitis, operation logs were used to verify the diagnosis (Paper II). In Paper III, patients with diagnosed acute cholecystitis were included and followed with repeated daily ultrasounds, during admission. The study had a descriptive design, where measures of the gallbladder wall, gallbladder volume, and gallbladder wall oedema were followed over time. Paper IV consists of a register-based cohort study with retrospectively analysed data from the National Register for Gallstone surgery. Out-of-hours surgery was considered independent variable and the primary outcome was any complication within 30 days. Secondary outcomes were proportion of open procedures and operative time exceeding two hours. Logistic regression models were used to adjust for confounders. Results: Papers I and II: Sensitivity for surgeon-performed ultrasound was 88.2% in diagnosing gallstones. Specificity was 99.0% and the accuracy was 94.4%. The sensitivity for surgeon-performed ultrasound in diagnosing acute cholecystitis was 60.0%, specificity 98.6%, and accuracy 93.9%. For appendicitis the sensitivity was 53.3%, specificity 89.7%, and accuracy 77.3%. Paper III: The gallbladder volume and gallbladder wall thickness were mostly stable over time, with a slight tendency to decrease among the 37 patients that received repeated examinations. The presence of gallbladder wall oedema did not change over time. Paper IV: Out-of-hours cholecystectomy did not result in a higher proportion of complications 15.6% versus 13.6% (adjusted odds ratio 1.12 (95% CI 0.99-1.28)), but in a higher proportion of open procedures 37.9% versus 28.9% (adjusted odds ratio 1.39 (1.25-1.54)). There was a lower proportion of long procedures out of hours, 40.4% versus 55.8% (adjusted odds ratio 0.63 (0.58-0.69)). Conclusion: Surgeon-performed ultrasound can be used to diagnose gallstones with high accuracy. Diagnosing acute cholecystitis and appendicitis with ultrasound is more challenging, but examinations with a positive test can help to confirm a clinically suspected diagnosis. The use of ultrasonography in preoperative risk scoring for acute cholecystitis needs to be further evaluated. Out-of-hours surgery for acute cholecystitis is not associated with a higher risk of complications, but with a higher proportion of open procedures

Divorce Reform—One State’s Solution

Although New York has long been a leader in reform legislation, it has also had one of the most ineffective divorce laws in the nation. Therefore, it was not unrealistic to hope that when New York recently revised its divorce laws the new product would serve as a model for future reforms in other jurisdictions. While the new law as finally enacted is defective in several respects, its provisions reflect an attempt to accommodate the basic reform trends in current divorce law. This comment investigates briefly the evolution of governmental controls of divorce, the American tradition prior to the New York reform, and the implications of the procedures finally adopted by that state

Assessing the efficiencies and challenges for nutrient uptake by aquatic plants

Aquatic plant meadows are valuable components to the 'coastal filter' and it is important to understand the processes that drive their ability to cycle nutrients. However, at present, the field-based evidence for understanding the drivers of nutrient uptake by plants is lacking. This study aimed to investigate how well individual shoots of aquatic plants could meet their nitrogen demands using the sediment nutrient pool (porewater ammonium) and to explore which traits helped to facilitate such uptake. Several species were investigated in shallow, submerged (2-4 m) mixed-species communities in the northern Baltic Sea using incubation experiments with enriched ammonium. After a 3.5 h incubation time, individuals were collected and analysed for nitrogen (% DW) and N-15 (at-%) concentrations. Uptake by plants was calculated per unit nitrogen in response to the N-15 labelled source and to overall nitrogen availability. Background porewater ammonium availability was highly variable between individual plants. Species identity did not significantly affect uptake metrics and the effect of ambient porewater availability was weak. As biomass increased there were significant logarithmic declines in the 95th quantiles of nutrient uptake rates, ambient porewater nutrient availability and aboveground nitrogen tissue concentrations (% DW). Such findings suggested that uptake rates of plants were significantly demand driven and the nutrient conditions of the porewater were significantly driven by the demands of the plant. Findings parameterised the unfulfilled potential for some aquatic plants to cycle nutrients more efficiently and highlighted the potential importance of access to new nutrient sources as a way of enhancing nutrient cycling by aquatic plants. Plant traits and community properties such as the activity of infauna could facilitate such an access and are likely important for nutrient uptake.Peer reviewe

Variable contributions of seafloor communities to ecosystem metabolism across a gradient of habitat-forming species

The contributions of habitat-forming species to the biodiversity and ecosystem processes of marine and terrestrial ecosystems are widely recognized. Aquatic plants are considered foundation species in shallow ecosystems, as they maintain biodiversity and sustain many ecosystem functions such as primary production and respiration. Despite the increasing amount of biodiversity-ecosystem functioning experiments in seagrass habitats, the effects of benthic variability on ecosystem functioning are rarely investigated across spatially variable aquatic plant habitats. Here, we quantitatively link seasonal variability in seafloor metabolism (i.e. gross primary production and community respiration) with major benthic community components (i.e. microphytobenthos, aquatic plants and macrofauna) across a structural complexity gradient of habitat-forming species (in terms of shoot density and biomass), ranging from bare sand, to a sparse mixture of plants to a dense monospecific seagrass meadow. The increasing complexity gradient enhanced the magnitude of the relationships between benthic community and seafloor metabolism. The daily average seafloor metabolism per season at the bare site was similar to the sparse site, highlighting the role of microphytobenthos for seafloor metabolism in shallow unvegetated sediments. The contribution of the associated macrofauna to the seafloor respiration was similar to the aquatic plant community contribution. Infauna was the main macrofaunal component significantly explaining the seasonal variability of seafloor respiration. However, benthic community-metabolism relationships were stronger within the plant community than within the macrofauna community (i.e. steepest slopes and lowest p-values). Understanding these relationships are a priority since climate change and biodiversity loss are reducing habitat complexity around the world, jeopardizing valuable ecosystem functions and services.Peer reviewe

Effects of depth and overgrowth of ephemeral macroalgae on a remote subtidal NE Atlantic eelgrass (Zostera marina) community

We conducted a short-term field sampling complemented with time integrating stable isotope analysis to holistically investigate status and ecological interactions in a remote NE Atlantic Zostera marina meadow. We found high nutrient water concentrations, large biomass of fast-growing, ephemeral macroalgae, low abundance, and biodiversity of epifauna and a food web with thornback ray (Raja clavata) as intermediate and cod (Gadus morhua) as top predator. We observed no variation with increasing depth (3.5-11 m) except for decreasing shoot density and biomass of Zostera and macroalgae. Our results indicate that the Finnoya Zostera ecosystem is eutrophicated. During the past three to four decades, nutrients from aquaculture have steadily increased to reach 75% of anthmpogenic input while the coastal top predator cod has decreased by 50%. We conclude that bottom-up regulation is a predominant driver of change since top-down regulation is generally weak in low density and exposed Zostera ecosystems such as Finnoya.Peer reviewe

Unveiling the complexity and ecological function of aquatic macrophyte-animal networks in coastal ecosystems

Network theory offers innovative tools to explore the complex ecological mechanisms regulating species associations and interactions. Although interest in ecological networks has grown steadily during the last two decades, the application of network approaches has been unequally distributed across different study systems: while some kinds of interactions (e.g. plant–pollinator and host–parasite) have been extensively investigated, others remain relatively unexplored. Among the latter, aquatic macrophyte–animal associations in coastal environments have been largely neglected, despite their major role in littoral ecosystems. The ubiquity of macrophyte systems, their accessibility and multi-faceted ecological, economical and societal importance make macrophyte–animal systems an ideal subject for ecological network science. In fact, macrophyte–animal networks offer an aquatic counterpart to terrestrial plant–animal networks. In this review, we show how the application of network analysis to aquatic macrophyte–animal associations has the potential to broaden our understanding of how coastal ecosystems function. Network analysis can also provide a key to understanding how such ecosystems will respond to on-going and future threats from anthropogenic disturbance and environmental change. For this, we: (i) identify key issues that have limited the application of network theory and modelling to aquatic animal– macrophyte associations; (ii) illustrate through examples based on empirical data how network analysis can offer new insights on the complexity and functioning of coastal ecosystems; and (iii) provide suggestions for how to design future studies and establish this new research line into network ecology.Peer reviewe

Fucoid brown algae inject fucoidan carbon into the ocean

Peer reviewe