Our aim was to quantify microplastic ingestion by fish assemblages in two tropical Brazilian estuaries and to evaluate whether biological and ecological factors influence the ingestion of ...microplastics by fish species. Of 2233 fish from both estuaries (from 69 species) examined in this study, 9% of the individuals (24 species) had microplastics in their gut contents. Microplastic ingestion occurred irrespective of fish size and functional group. The diet of fish species was analyzed based on prey items identified in the fish's full stomach contents and five feeding guilds were defined. Microplastics were common throughout all feeding guilds. Low (average ingestion values 1.06±0.30 items/total fish) but widespread occurrence among estuaries also indicates proliferation of microplastic pollution. Our findings highlight the need to focus on assemblage level studies to understand the real magnitude of the problem and emphasize the urgency of mitigation measures directed at microplastic pollution in estuarine ecosystems.
•We analyzed microplastic ingestion in 69 fish species collected along two estuaries.•Microplastic ingestion was widespread in fish assemblages in two tropical estuaries.•Microplastic ingestion was independent of fish size and fish functional groups.•Microplastics were observed in fish from five different feeding guilds.•The level of anthropogenic pressures did not influence microplastic ingestion.
The functional diversity of fish communities was studied along the salinity gradient of two estuaries in Northeast Brazil subjected to different anthropogenic pressures, to gain a better ...understanding of the response of fish communities to disturbance. We evaluated functional complementarity indices, redundancy and analysed functional composition through functional groups based on combinations of different traits. The fish communities in both estuaries share similar functions performed by few functional groups. The upstream areas had generally lower taxonomic, functional diversity and lower redundancy, suggesting greater vulnerability to impacts caused by human activities. Biomass was slightly more evenly distributed among functional groups in the less disturbed estuary, but total biomass and redundancy were lower in comparison to the urbanized estuary. The present findings lend strength to the notion that the less disturbed estuary may be more susceptible to anthropogenic impacts, underscoring the need for more effective conservation measures directed at this estuary.
•Functional diversity was studied in two tropical estuaries with different impacts.•Fish communities share similar functions performed by few functional groups.•Distinct salinity sectors exhibit different degrees of vulnerability.•The less impacted estuary was considered more vulnerable to disturbance.•More effective management measures are suggested for both estuaries.
Ecosystem functioning is assessed through research that spans multiple biological organisational levels and disciplines, and it is quantified by measuring the magnitude and dynamics of several ...processes. This quantification is done using different tools, and the resulting information from each tool is often interpreted independently. Our main aim was to contribute to the understanding of the functioning of tropical estuarine ecosystems facing anthropogenic impact, using information on fish diversity, traits and food webs. We used biological and environmental data from 2 Brazilian estuaries with different levels and types of human disturbance: the heavily impacted Paraiba estuary and the environmentally protected Mamanguape estuary (IUCN, Protected Area Category V). Fish assemblages and their prey were collected along the salinity gradient in the dry and wet seasons, and we evaluated (1) species taxonomic diversity, (2) functional diversity based on effect traits and (3) food-web structure through analyses of the natural abundance of stable isotopes (carbon and nitrogen). Species turnover, i.e. the change in species identity, along each estuary was relatively high, and this dissimilarity was considerably greater than the trait turnover (i.e. low functional β-diversity). These results highlight that, although habitat selection was an important driver of the coexistence of fish species due to spatial environmental gradients, the competition for resources might be high because species tended to use the system in a similar way. The relatively narrow range of both δ13C and δ15N values among fish species also implies competition for the same resources. Moreover, the δ15N values indicated anthropogenic inputs of nitrogen in both estuaries, regardless of their protection framework, which highlights the need for more effective conservation measures.
The aim of the present study was to test whether different degrees of human activity affect the diet of the Brazilian silverside Atherinella brasiliensis in two tropical estuaries. Fish were ...collected along the salinity gradient of two Brazilian estuaries, the heavily impacted Paraiba Estuary and the less impacted Mamanguape Estuary, in the dry and wet seasons. The findings confirm that A. brasiliensis has generalist feeding habits and is able to change its diet under different environmental conditions. The results indicate clear spatial (i.e. along the estuarine gradient) changes in diet composition in both estuaries, but diet was also influenced by the degree of anthropogenic disturbance. During the wet season in the nutrient enriched Paraiba Estuary, when human activity was higher, the diet of A. brasiliensis was poorer and dominated by few dietary items, reflecting the potential impoverishment of prey items in this heavily disturbed system. The specimens collected in the most affected estuary also had a greater frequency of micro‐plastics and parasites in their stomachs, reflecting the greater degree of human disturbance in the estuary. The present findings suggest that the diet of A. brasiliensis could be a useful indicator of changes in the ecological quality of these and other tropical estuaries of the western Atlantic Ocean.
We aim to investigate if we need additional trials on exercise in knee osteoarthritis (OA) to accept a certain effect size to be a 'true' effect size, and new studies are not needed anymore.
We ...performed a secondary analyses of a meta-analysis of studies on patients with knee osteoarthritis, on pain immediately post treatment. We performed five different analysis: a) we evaluated publication bias, b) we performed subgroup analysis, c) a sensitivity analysis based on the overall risk of bias (RoB) score, d) a cumulative meta-analysis and e) we developed an extended funnel plot to explore the potential impact of a new study on the summary effect estimate.
We included 42 studies with in total 6863 patients. The analyses showed that a) there is no clear publication bias, b) subgrouping did not affect the overall effect estimate, c) the effect estimate of exercise is more consistent (no heterogeneity) in the studies of low RoB, d) the benefit of exercise was clear since 2010 and e) the extended funnel plot suggests that an additional study has a none or very limited impact to change the current effect estimate.
Exercise is effective and clinically worthwhile in reducing pain immediately post treatment compared to no or minimal interventions in patients with knee OA and adding new data will unlikely change this conclusion.
Objective
In this retrospective, single-center observational study, we investigated whether discontinuing metformin for at least 48 h prevents metformin-induced
18
Ffluorodeoxyglucose (FDG) uptake ...in all segments of the colon.
Methods
Patients with type 2 diabetes who were using metformin before undergoing an FDG PET/CT scan were included. Two groups were created: patients who discontinued metformin for less than 48 h (< 48 h group) and patients who discontinued metformin for between 48 and 72 h (≥ 48 h group). A control group comprised non-diabetic patients who were not using metformin before undergoing an FDG PET/CT. We visually scored the uptake of FDG in four segments of the colon—the ascendens, transversum, descendens, and rectosigmoid—using a four-point scale (1–4) and considered scores of 3 or 4 to be clinically significant.
Results
Colonic FDG uptake in the ≥ 48 h group (
n
= 23) was higher than uptake in the control group (
n
= 96) in the colon descendens odds ratio (OR) 14.0; 95% confidence interval (CI) 4.8–40.9;
p
value: 0.001 and rectosigmoid (OR 11.3; 95% CI 4.0–31.9;
p
value: 0.001), and there was no difference in the colon ascendens and transversum. Colonic FDG uptake in the < 48 h group (
n
= 25) was higher than uptake in the ≥ 48 h group (
n
= 23) in the colon transversum (OR 4.8; 95% CI 1.3–18.5;
p
value: 0.022) and rectosigmoid (
p
value: 0.023), and there was no difference in the colon ascendens and descendens.
Conclusions
Discontinuing metformin for 48 h before undergoing an FDG PET/CT still gives a high uptake in the distal parts of the colon when compared with non-diabetic patients who are not using metformin. Discontinuing metformin for 48 h seems to be useful for scanning the more proximal segments of the colon.
A right-to-left shunt can be identified by contrast transcranial Doppler ultrasonography (c-TCD) at rest and/or after a Valsalva maneuver (VM) or by arterial blood gas (ABG) measurement. We assessed ...the influence of controlled strain pressures and durations during VM on the right-to-left passage of microbubbles, on which depends the shunt classification by c-TCD, and correlated it with the right-to-left shunt evaluation by ABG measurements in stroke patients with patent foramen ovale (PFO).
We evaluated 40 stroke patients with transesophageal echocardiography-documented PFO. The microbubbles were recorded with TCD at rest and after 4 different VM conditions with controlled duration and target strain pressures (duration in seconds and pressure in cm H2O, respectively): V5-20, V10-20, V5-40, and V10-40. The ABG analysis was performed after pure oxygen breathing in 34 patients, and the shunt was calculated as percentage of cardiac output.
Among all VM conditions, V5-40 and V10-40 yielded the greatest median number of microbubbles (84 and 95, respectively; P<0.01). A significantly larger number of microbubbles were detected in V5-40 than in V5-20 (P<0.001) and in V10-40 than in V10-20 (P<0.01). ABG was not sensitive enough to detect a shunt in 31 patients.
The increase of VM expiratory pressure magnifies the number of microbubbles irrespective of the strain duration. Because the right-to-left shunt classification in PFO is based on the number of microbubbles, a controlled VM pressure is advised for a reproducible shunt assessment. The ABG measurement is not sensitive enough for shunt assessment in stroke patients with PFO.
We present the first angle resolved measurements of extraordinary optical transmission (EOT) through hole array gratings in a gold film. Varying the lattice spacing of the arrays and looking at ...higher diffraction orders, we retrieve the angular emission pattern of the constituent holes with better signal to noise ratio than with single-hole experiments. We present a method to determine separately the angular dependence of the direct and resonant contribution to EOT by using the spectral features of the diffraction orders together with an established model. The comparison of our results with the known angular transmission of a single hole in a metal film yields a good agreement for s-polarized light. Deviations are found for illumination with p-polarized light and we address the discrepancy with Coupled Mode Model calculations and Finite Difference Time Domain simulations. These measured deviations are currently not fully understood.
PDF
