Understanding the migratory movements of fish between habitats is an important priority for fisheries management. Carbon (C) and nitrogen (N) stable isotopes were used to evaluate the degree of ...movement and residency for five fish species collected from coral reefs in Queensland, Australia. Isotope values of fish were measured and compared between slow-turnover muscle tissue and fast-turnover liver tissue, with isotopic agreement between liver and muscle generally indicating resident animals, and relatively low C isotope values in muscle indicating migrants. Three fish species, rabbitfish (Siganus fuscescens), painted sweetlips (Diagramma labiosum) and Guenther's wrasse (Pseudolabrus guentheri) showed relatively consistent carbon isotope values between muscle and liver tissue as expected for resident populations. One quarter of bream (Acanthopagrus australis) individuals showed much lower δ13C values in muscle than liver. These low values diverged from the −10 to −15‰ values of residents and were more similar to the −20‰ values of fish collected from coastal riverine habitats, the presumed migration source. Moses perch (Lutjanus russelli) also showed substantial differences between muscle and liver C isotopes for about a quarter of individuals, but the overall higher C values of these individuals indicated they may have switched diets within island habitats rather than migrating. Our results were consistent with previous studies of fish residency and indicate that measuring stable isotopes in multiple tissues provides a useful methodology for characterizing fish residency in inshore areas.
Bottom waters of the Louisiana mid-continental shelf regularly become hypoxic with < 64 mmol m⁻³ (< 2 mg/1) dissolved oxygen (DO) during spring and summer months. This hypoxia is ultimately due to ...freshwater and nutrient inputs from the Mississippi River system. Two local controls of hypoxia were investigated, rates of respiration (R) in bottom waters versus the metabolic age of bottom water oxygen pools, estimated as time since oxygen saturation (TSOS). Fast R could lead to hypoxia even in recently formed bottom waters, while conversely, extended periods of bottom water isolation and TSOS could lead to hypoxia formation even when R is slow. Shipboard 24 h dark R measurements that were carried out during July shelfwide cruises in 2007 and 2008 indicated relatively slow R and long TSOS for hypoxic waters. To check these shipboard incubation results, oxygen isotopes were measured and modelled as field indicators of past R (RP), a time-averaged measure of in situ R that occurred prior to sampling during the days-to-weeks of oxygen drawdown in bottom waters. The isotope measurements showed that shipboard incubation R (RI) experiments underestimated RP that was 18–34% higher for hypoxic bottom waters than normoxic (DO > 64 mmol m⁻³) bottom waters. The field isotope measurements also showed that RP was above average and more important when and where river influences were larger, especially in the flood year 2008 and on the eastern shelf. In contrast, bottom water metabolic ages estimated as TSOS were above average and more important for hypoxia formation when and where river influences were smaller, especially in the average-flow year 2007 and on the western shelf.
Stable isotope tracers are used to solve ecological problems, and sophisticated modelling approaches are now available to help interpret measured isotope data. However, models such as IsoSource and ...SIAR can go a step too far in producing mean and median values when there are too many sources and not enough tracers. The models solve these underdetermined problems by assuming that some of the many possible or feasible solutions are more likely than others. I promote the alternative idea that all feasible solutions are equally likely, and support use of minimum and maximum (‘minmax’) solutions as the appropriate way to view results from underdetermined systems.
Trace element accumulation pathways are important in many ecological and toxicological studies on aquatic organisms, yet these pathways are often poorly understood. To study the influence of diet and ...environment on the trace element composition of species within estuarine food webs, we performed a community level assessment of 28 trace elements (including major and minor elements) in common fish and prawn taxa across four estuaries, and in fish, prawn, and other invertebrate taxa within a single estuary. Despite sediment substrates from the four estuaries having distinctly different geochemical compositions, food web samples showed no separation by estuary, but clear separation by taxa. Grouping of taxa by trace elements was related to feeding ecology, with pelagic taxa separated from benthic taxa, and mixed feeding by generalist taxa. Arsenic and selenium were more concentrated in benthic fish, while aluminium, barium, copper, iron, manganese, vanadium, and zinc were more concentrated in pelagic fish. Trophic level did not appear to influence trace element composition. Previous laboratory studies have shown that food sources influence trace element concentrations in marine taxa and this study confirms that this also occurs in natural food webs. These results improve our understanding of the dominant importance of diet and physiology in controlling the trace element composition of species within estuarine food webs.
•We performed a community level assessment of trace elements in estuarine food webs.•Estuaries were geochemically distinct.•Animals did not match sediments but were grouped by taxa.•We identified a benthic-pelagic mixing gradient of trace elements across taxa.•Our results provide new insights into broad scale trace element accumulation.
There is growing evidence that opioids are overprescribed following surgery. Improving prescribing requires understanding factors associated with opioid consumption.
To describe opioid prescribing ...and consumption for a variety of surgical procedures and determine factors associated with opioid consumption after surgery.
A retrospective, population-based analysis of the quantity of opioids prescribed and patient-reported opioid consumption across 33 health systems in Michigan, using a sample of adults 18 years and older undergoing surgery. Patients were included if they were prescribed an opioid after surgery. Surgical procedures took place between January 1, 2017, and September 30, 2017, and were included if they were performed in at least 25 patients.
Opioid prescription size in the initial postoperative prescription.
Patient-reported opioid consumption in oral morphine equivalents. Linear regression analysis was used to calculate risk-adjusted opioid consumption with robust standard errors.
In this study, 2392 patients (mean age, 55 years; 1353 women 57%) underwent 1 of 12 surgical procedures. Overall, the quantity of opioid prescribed was significantly higher than patient-reported opioid consumption (median, 30 pills; IQR, 27-45 pills of hydrocodone/acetaminophen, 5/325 mg, vs 9 pills; IQR, 1-25 pills; P < .001). The quantity of opioid prescribed had the strongest association with patient-reported opioid consumption, with patients using 0.53 more pills (95% CI, 0.40-0.65; P < .001) for every additional pill prescribed. Patient-reported pain in the week after surgery was also significantly associated with consumption but not as strongly as prescription size. Compared with patients reporting no pain, patients used a mean (SD) 9 (1) more pills if they reported moderate pain and 16 (2) more pills if they reported severe pain (P < .001). Other significant risk factors included history of tobacco use, American Society of Anesthesiologists class, age, procedure type, and inpatient surgery status. After adjusting for these risk factors, patients in the lowest quintile of opioid prescribing had significantly lower mean (SD) opioid consumption compared with those in the highest quintile (5 2 pills vs 37 3 pills; P < .001).
The quantity of opioid prescribed is associated with higher patient-reported opioid consumption. Using patient-reported opioid consumption to develop better prescribing practices is an important step in combating the opioid epidemic.
Policies intended to develop and utilize uniformed scientists and engineers are often misapplied and impede effective employment. Uniformed scientists and engineers are uniquely suited to link ...technical possibilities to operational realities; developing these capabilities will help uniformed scientists and engineers maximize their contributions to the acquisition community and to the combat power of the Air Force.
Repair of midsize (4–6 cm) ventral hernias is challenging given lack of guidelines. Within this context, we sought to characterize surgical approach among patients undergoing repair of midsize ...ventral hernias within the only population-level, clinically-nuanced hernia registry in the US.
Retrospective cohort study of patients undergoing ventral hernia repair in the Michigan Surgical Quality Collaborative Core Optimization Hernia Registry (MSQCCOHR). MSQCCOHR is the only US population-level registry that captures clinically-nuanced data pertaining to patient hernia characteristics. We included patients who underwent repair of a 4–6 cm hernia from January 1, 2020-June 30, 2022. We stratified repair type as open or minimally invasive and used a multivariable logistic regression model to identify factors associated with MIS approach. Secondary outcomes included complications rate.
Among 771 patients, mean hernia width (SD) was 4.7 cm (0.8) and 339 (44 %) underwent MIS approach. Patients with MIS approach had lower BMI (33.5 vs 34.8, p = 0.02) and less often were ASA class III (47.5% vs 54.6 %, p = 0.02) or ASA class IV (2.4% vs 4.2 %, p = 0.02). MIS approach was associated with smaller mean hernia width (4.71 cm vs 4.84 cm, p = 0.02) and was used more often in the elective setting (94.4% vs 84.0 %, p < 0.01). In the multivariable logistic regression model, higher BMI (aOR 0.97, 95 % CI 0.94–0.99) and urgent/emergent surgery (aOR 0.43, 95 % CI 0.24–0.79) were associated with lower odds of MIS. We found no significant association between MIS and risk of complications (aOR 0.62, 95 % CI 0.37–1.04). Among patients undergoing MIS, more than half (n = 236, 69.6 %) had a robotic approach but there were few patient factors associated with this.
Among patients with midsize hernias, few patient-level factors are associated with approach. This may indicate that surgeon preference factors largely into this decision.
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