Use of statewide financial incentives to improve documentation of hernia and mesh characteristics in ventral hernia repair.

BACKGROUND: Documentation of intraoperative details is critical for understanding and advancing hernia care, but is inconsistent in practice. Therefore, to improve data capture on a statewide level, we implemented a financial incentive targeting documentation of hernia defect size and mesh use. METHODS: The Abdominal Hernia Care Pathway (AHCP), a voluntary pay for performance (P4P) initiative, was introduced in 2021 within the statewide Michigan Surgical Quality Collaborative (MSQC). This consisted of an organizational-level financial incentive for achieving 80% performance on eight specific process measures for ventral hernia surgery, including complete documentation of hernia defect size and location, as well as mesh characteristics and fixation technique. Comparisons were made between AHCP and non-AHCP sites in 2021. RESULTS: Of 69 eligible sites, 47 participated in the AHCP in 2021. There were N = 5362 operations (4169 at AHCP sites; 1193 at non-AHCP sites). At AHCP sites, 69.8% of operations had complete hernia documentation, compared to 50.5% at non-AHCP sites (p < 0.0001). At AHCP sites, 91.4% of operations had complete mesh documentation, compared to 86.5% at non-AHCP sites (p < 0.0001). The site-level hernia documentation goal of 80% was reached by 14 of 47 sites (range 14-100%). The mesh documentation goal was reached by 41 of 47 sites (range 4-100%). CONCLUSIONS: Addition of an organizational-level financial incentive produced marked gains in documentation of intra-operative details across a statewide surgical collaborative. The relatively large effect size-19.3% for hernia-is remarkable among P4P initiatives. This result may have been facilitated by surgeons' direct role in documenting hernia size and mesh use. These improvements in data capture will foster understanding of current hernia practices on a large scale and may serve as a model for improvement in collaboratives nationally.

Consistencies in the dietary and isotopic niche of spotted seatrout, Cynoscion nebulosus, across a salinity gradient within a coastal Louisiana estuary.

Estuaries are essential habitats for recreational and commercial fish that are shaped by both natural and anthropogenic processes. In Louisiana a combination of climate change and planned coastal restoration actions is predicted to increase freshwater introduction to coastal estuaries. As such there is a need to quantify the relationships between estuarine fish ecology and salinity to aid in predicting how species will respond to shifts in salinity. We investigated the relative abundance and dietary niches of adult (24.5 ± 5.4 cm standard length) spotted seatrout Cynoscion nebulosus across varying salinity regimes (oligohaline, mesohaline, and polyhaline) within Barataria Bay, Louisiana, using a combination of net sampling and gut content and stable isotopes analysis. We found that the relative abundance of C. nebulosus was lowest at the oligohaline site, translating to approximately five fewer fish captured for every single psu decrease in a site's average annual salinity. In contrast, we found that diets and, to a lesser extent, isotopic niches had a high degree of overlap across sites with differing salinity regimes. Fish and penaeid shrimp were the most common and important prey taxa recovered from guts at all sites. The small isotopic differences found among sites were likely due to spatial variation in hydrogeochemical baselines, and the observed isotopic overlap provides support for the idea that C. nebulosus move between adjacent salinity regimes and forage throughout Barataria Bay. Our results contribute to a greater understanding of the salinity preference and trophic ecology of C. nebulosus that can aid in predicting their responses to future salinity and habitat changes within Barataria Bay associated with predicted climate change and planned coastal restoration actions.

Application of Component Separation and Short-Term Outcomes in Ventral Hernia Repairs.

INTRODUCTION: Component separation (CS) techniques have evolved in recent years. How surgeons apply the various CS techniques, anterior component separation (aCS) versus posterior component separation (pCS), by patient and hernia-specific factors remain unknown in the general population. Improving the quality of ventral hernia repair (VHR) on a large scale requires an understanding of current practice variations and how these variations ultimately affect patient care. In this study, we examine the application of CS techniques and the associated short-term outcomes while taking into consideration patient and hernia-specific factors. METHODS: We retrospectively reviewed a clinically rich statewide hernia registry, the Michigan Surgical Quality Collaborative Hernia Registry, of persons older than 18 y who underwent VHR between January 2020 and July 2021. The exposure of interest was the use of CS. Our primary outcome was a composite end point of 30-d adverse events including any complication, emergency department visit, readmission, and reoperation. Our secondary outcome was surgical site infection (SSI). Multivariable logistic regression examined the association of CS use, 30-d adverse events, and SSI with patient-, hernia-, and operative-specific variables. We performed a sensitivity analysis evaluating for differences in application and outcomes of the posterior and aCS techniques. RESULTS: A total of 1319 patients underwent VHR, with a median age (interquartile range) of 55 y (22), 641 (49%) female patients, and a median body mass index of 32 (9) kg/m2. CS was used in 138 (11%) patients, of which 101 (73%) were pCS and 37 (27%) were aCS. Compared to patients without CS, patients undergoing a CS had larger median hernia widths (2.5 cm (range 0.01-23 cm) versus 8 cm (1-30 cm), P < 0.001). Of the CS cases, 49 (36%) performed in hernias less than 6 cm in size. Following multivariate regression, factors independently associated with the use of a CS were diabetes (odds ratio [OR]: 2.00, 95% confidence interval [CI]: 1.19-3.36), previous hernia repair (OR: 1.88, 95% CI: 1.20-2.96), hernia width (OR: 1.28, 95% CI: 1.22-1.34), and an open approach (OR: 3.83, 95% CI: 2.24-6.53). Compared to patients not having a CS, use of a CS was associated with increased odds of 30-d adverse events (OR: 1.88 95% CI: 1.13-3.12) but was not associated with SSI (OR: 1.95, 95% CI: 0.74-4.63). Regression analysis demonstrated no differences in 30-d adverse events or SSI between the pCS and aCS techniques. CONCLUSIONS: This is the first population-level report of patients undergoing VHR with concurrent posterior or aCS. These data suggest wide variation in the application of CS in VHR and raises a concern for potential overutilization in smaller hernias. Continued analysis of CS application and the associated outcomes, specifically recurrence, is necessary and underway.

The impact of frailty on ventral hernia repair outcomes in a statewide database.

INTRODUCTION: Preoperative frailty is a strong predictor of postoperative morbidity in the general surgery population. Despite this, there are a paucity of research examining the effect of frailty on outcomes after ventral hernia repair (VHR), one of the most common abdominal operations in the USA. We examined the association of frailty with short-term postoperative outcomes while accounting for differences in preoperative, operative, and hernia characteristics. METHODS: We retrospectively reviewed the Michigan Surgery Quality Collaborative Hernia Registry (MSQC-HR) for adult patients who underwent VHR between January 2020 and January 2022. Patient frailty was assessed using the validated 5-factor modified frailty index (mFI5) and categorized as follows: no (mFI5 = 0), moderate (mFI5 = 1), and severe frailty (mFI5 ≥ 2). Our primary outcome was any 30-day complication. Multivariable logistic regression was used to evaluate the association of frailty with outcomes while controlling for patient, operative, and hernia variables. RESULTS: A total of 4406 patients underwent VHR with a mean age (SD) of 55 (15) years, 2015 (46%) females, and 3591 (82%) white patients. The mean (SD) BMI of the cohort was 33 (8) kg/m2. A total of 2077 (47%) patients had no frailty, 1604 (36%) were moderately frail, and 725 (17%) were severely frail. The median hernia size (interquartile range) was 2.5 cm (1.5-4.0 cm). Severe frailty was associated with increased odds of any complication (adjusted Odds Ratio (aOR) 3.12, 95% CI 1.78-5.47), serious complication (aOR 5.25, 95% CI 2.17-13.19), SSI (aOR 3.41, 95% CI 1.58-7.34), and post-discharge adverse events (aOR 1.70, 95% CI 1.24-2.33). CONCLUSION: After controlling for patient, operative, and hernia characteristics, frailty was independently associated with increased odds of postoperative complications. These findings highlight the importance of preoperative frailty assessment for risk stratification and to inform patient counseling.

Variation of ventral and incisional hernia repairs in kidney transplant recipients.

INTRODUCTION: As survivorship following kidney transplant continues to improve, so does the probability of intervening on common surgical conditions, such as ventral or incisional hernia, in this population. Ventral hernia management is known to vary across institutions and this variation has an impact on patient outcomes. We sought to evaluate hospital level variation of ventral or incisional hernia repair (VIHR) in the kidney transplant population. METHODS: We performed a retrospective review of 100% inpatient Medicare claims to identify patients who underwent kidney transplant between 2007 and 2018. The primary outcome was 1- and 3-year ventral or incisional risk- and reliability-adjusted VIHR rates. Patient and hospital characteristics were evaluated across risk- and reliability-adjusted VIHR rate tertiles. Models were adjusted for age, sex, race, and Elixhauser comorbidities. RESULTS: Overall, 139,741 patients underwent kidney transplant during the study period with a mean age (SD) of 51.6 (13.7) years. 84,717 (60.6%) were male, and 72,657 (52.0%) were white. Median follow up time was 5.4 years. 2098 (1.50%) patients underwent VIHR. the 1 year risk- and reliability-adjusted hernia repair rates were 0.49% (95% Conf idence Interval (CI) 0.48-0.51, range 0.31-0.59) in tertile 1, 0.63% (95% CI 0.62-0.63, range 0.59-0.68) in tertile 2, and 0.98 (95% CI 0.91-1.05, range 0.68-2.94) in tertile 3. Accordingly, compared to hospitals in tertile 1, the odds of post-transplant hernia repair tertile 2 hospitals were 1.78 (95% CI 1.37-2.31) and at tertile 3 hospitals 3.53 (95% CI 2.87-4.33). CONCLUSIONS: In a large cohort of Medicare patients undergoing kidney transplant, the overall cumulative incidence of hernia repair varied substantially across hospital tertiles. Patient and hospital characteristics varied across tertile, most notably in diabetes and obesity. Future research is needed to understand if program and surgeon level factors are contributing to the observed variation in treatment of this common disease.

Supernova triggers for end-Devonian extinctions.

The Late Devonian was a protracted period of low speciation resulting in biodiversity decline, culminating in extinction events near the Devonian-Carboniferous boundary. Recent evidence indicates that the final extinction event may have coincided with a dramatic drop in stratospheric ozone, possibly due to a global temperature rise. Here we study an alternative possible cause for the postulated ozone drop: a nearby supernova explosion that could inflict damage by accelerating cosmic rays that can deliver ionizing radiation for up to [Formula: see text] ky. We therefore propose that the end-Devonian extinctions were triggered by supernova explosions at [Formula: see text], somewhat beyond the "kill distance" that would have precipitated a full mass extinction. Such nearby supernovae are likely due to core collapses of massive stars; these are concentrated in the thin Galactic disk where the Sun resides. Detecting either of the long-lived radioisotopes [Formula: see text] or [Formula: see text] in one or more end-Devonian extinction strata would confirm a supernova origin, point to the core-collapse explosion of a massive star, and probe supernova nucleosynthesis. Other possible tests of the supernova hypothesis are discussed.

Association of Postoperative Opioid Prescription Size and Patient Satisfaction.

OBJECTIVE: To evaluate the association between postoperative opioid prescription size and patient-reported satisfaction among surgical patients. SUMMARY BACKGROUND DATA: Opioids are overprescribed after surgery, which negatively impacts patient outcomes. The assumption that larger prescriptions increase patient satisfaction has been suggested as an important driver of excessive prescribing. METHODS: This prospective cohort study evaluated opioid-naive adult patients undergoing laparoscopic cholecystectomy, laparoscopic appendectomy, and minor hernia repair between January 1 and May 31, 2018. The primary outcome was patient satisfaction, collected via a 30-day postoperative survey. Satisfaction was measured on a scale of 0 to 10 and dichotomized into "highly satisfied" (9-10) and "not highly satisfied" (0-8). The explanatory variable of interest was size of opioid prescription at discharge from surgery, converted into milligrams of oral morphine equivalents (OME). Hierarchical logistic regression was performed to evaluate the association between prescription size and satisfaction while adjusting for clinical covariates. RESULTS: One thousand five hundred twenty patients met the inclusion criteria. Mean age was 53 years and 43% of patients were female. One thousand two hundred seventy-nine (84.1%) patients were highly satisfied and 241 (15.9%) were not highly satisfied. After multivariable adjustment, there was no significant association between opioid prescription size and satisfaction (OR 1.00, 95% CI 0.99-1.00). The predicted probability of being highly satisfied ranged from 83% for the smallest prescription (25 mg OME) to 85% for the largest prescription (750 mg OME). CONCLUSIONS: In a large cohort of patients undergoing common surgical procedures, there was no association between opioid prescription size at discharge after surgery and patient satisfaction. This implies that surgeons can provide significantly smaller opioid prescriptions after surgery without negatively affecting patient satisfaction.

Surgeon Variation in the Application of Robotic Technique for Abdominal Hernia Repair: A Mixed-Methods Study.

INTRODUCTION: Although the utilization of robotic technique for abdominal hernia repair has increased rapidly, there is no consensus as to when it should be applied for optimal outcomes. High variability exists within surgeon practices regarding how they use this technology, and the factors that drive robotic utilization remain largely unknown. This study aims to explore the motivating factors associated with surgeons' decisions to utilize a robotic approach for abdominal hernia repair. METHODS: An exploratory mixed-methods approach was utilized. Surgeons who performed abdominal hernia repairs were interviewed to identify impactful themes motivating surgical approach. This informed a retrospective analysis of ventral hernia repairs performed in 2020 within the Michigan Surgical Quality Collaborative. Surgeon robotic utilization rates were calculated. Among selective robotic users, multivariable regression evaluated the patient and hernia factors associated with robotic utilization. RESULTS: Qualitative analysis of 21 interviews revealed three dominant themes in the decision to utilize robotic technology: access and resources, surgeon comfort, and market factors. Among 71 surgeons caring for 1174 hernia patients, robotic utilization rates ranged from 0% to 98% of cases. There were 27 surgeons identified as selective robotic users, who cared for 423 patients. Multivariable regression revealed that hernia location was the only factor associated with robotic technique, with non-midline hernias associated with a 4.47 (95% confidence interval 1.34-14.88) higher odds of robotic repair than epigastric hernias. CONCLUSIONS: Major drivers of robotic technique for hernia repair were found to be perceived benefits and availability, rather than patient or hernia characteristics. These data will contribute to an understanding of surgeon decision-making and help develop improvements to patient care.

Incidence and trends of decision regret following elective hernia repair.

BACKGROUND: One approach to evaluate decision-making is using the concept of decision regret, which measures patient remorse after a healthcare decision. This is particularly important for elective, preference-sensitive conditions with multiple treatment options, such as ventral and inguinal hernia repair. In this study, we assessed decision regret among patients who pursued surgical management of ventral and inguinal hernias. METHODS: We retrospectively reviewed a statewide registry of adult patients who underwent elective ventral and inguinal hernia repair between January 2017 and March 2020 and completed a validated survey measuring decision regret. 30-day outcomes included complications, emergency department (ED) utilization, readmission, and reoperation. Multivariable logistic regression examined the association of regret with age, sex, race, insurance status, ASA, tobacco use, diabetes, admission status, surgical approach (open vs. laparoscopic vs. robotic), year, and outcomes. RESULTS: 8315 patients underwent surgery during the study period with a mean age of 60.5 (14.7) years and 1812 (22%) female patients. Among 2159 patients who underwent ventral hernia repair, 248 (11%) reported regret to undergo surgery, 64 (3%) experienced a complication, 160 (7%) visited an ED, 86 (4%) were readmitted, and 29 (1%) underwent reoperation. Outcomes associated with regret after ventral hernia repair included complications (OR 2.33, 95% CI 1.26-4.29) and readmission (OR 2.67, 95% CI 1.51-4.71). Among 6,156 patients who underwent inguinal hernia repair, 533 (9%) reported regret to undergo surgery, 41 (1%) experienced a complication, 304 (5%) visited an ED, 72 (1%) were readmitted, and 63 (1%) underwent reoperation. Outcomes associated with regret after inguinal hernia repair included ED visits (OR 2.03, 95% CI 1.44-2.87) and readmission (OR 4.23, 95% CI 2.35-7.61). CONCLUSION: Roughly 1 in 10 patients undergoing hernia repair report regret with their decision to undergo surgery. Developing a better understanding of the factors associated with decision regret after hernia repair may better inform both patients and surgeon decision-making.

Coaching as a Mechanism to Challenge Surgical Professional Identities.

BACKGROUND: The "surgical personality" is a mostly negative academic and cultural image of the surgeon as egotistical, paternalistic, and inflexible. Because of this image, surgeons have been viewed as resistant to change and some behaviors, vulnerability, for example, are viewed as "suspect" because they seemingly threaten professional competency. We report on exit interviews of surgeons who participated in a coaching program and demonstrate how their narratives challenge the surgical "personality" and forge an evolving and more open professional surgical identity. METHODS: We interviewed n = 34 bariatric surgeons at the end of a 2-year surgical coaching program. Transcribed interviews were analyzed in NVivo, computer-assisted qualitative data analysis software. Coding of transcripts was approached through iterative steps. We utilized an exploratory method; each member of our team independently examined 3 transcripts to evaluate emergent themes early in the investigation. The team met to discuss our independent themes and develop the codebook collectively. We created a descriptive framework for our first round of coding based on emerging themes and employed an interpretive framework to arrive at our themes. RESULTS: Three major themes emerged from our data. Participants in this study discussed the ways that participation in the coaching program initially conflicted with their identity as a competent professional. Surgeons were acutely aware of how participation might have destabilized their surgical identity because they might be viewed as vulnerable. Despite these concerns about image, surgeons found impetus for improvement because of poor outcome scores or because they desired early career affirmation. Finally, surgeons report that the safe spaces of intentional coaching contributed to their ideas about how surgeons, and ultimately surgery, can change. CONCLUSIONS: Participation in a coaching program challenged how surgeons thought of themselves in relationship to social and peer expectations. Our results indicate that surgeons do feel peer and social pressures related to identity but are much more complex and nuanced than has been previously discussed. The safe space of intentional coaching allowed participants to practice vulnerability without the pressures of sometimes caustic professional norms. Participants in this study viewed coaching as the way to improve the culture of surgery.

Assessing the effects of lipid extraction and lipid correction on stable isotope values (δ13 C and δ15 N) of blubber and skin from southern hemisphere humpback whales.

RATIONALE: The coupled analysis of δ13 C and δ15 N stable isotope values of blubber and skin biopsy samples is widely used to study the diet of free-ranging cetaceans. Differences in the lipid content of these tissues can affect isotopic variability because lipids are depleted in 13 C, reducing the bulk tissue 13 C/12 C. This variability in carbon isotope values can be accounted for either by chemically extracting lipids from the tissue or by using mathematical lipid normalisation models. METHODS: This study examines (a) the effects of chemical lipid extraction on δ13 C and δ15 N values in blubber and skin of southern hemisphere humpback whales, (b) whether chemical lipid extraction is more favourable than mathematical lipid correction and (c) which of the two tissues is more appropriate for dietary studies. Strategic comparisons were made between chemical lipid extraction and mathematical lipid correction and between blubber and skin tissue δ13 C and δ15 N values, as well as C:N ratios. Six existing mathematical normalisation models were tested for their efficacy in estimating lipid-free δ13 C for skin. RESULTS: Both δ13 C and δ15 N values of lipid-extracted skin (δ13 C: -25.57‰, δ15 N: 6.83‰) were significantly higher than those of bulk skin (δ13 C: -26.97‰, δ15 N: 6.15‰). Five of the six tested lipid normalisation models had small error terms for predicting lipid-free δ13 C values. The average C:N ratio of lipid-extracted skin was within the lipid-free range reported in other studies, whereas the average C:N ratio of blubber was higher than previously reported. CONCLUSIONS: These results highlight the need to account for lipids when analysing δ13 C and δ15 N values from the same sample. For optimised dietary assessments using parallel isotope analysis from a single sample, we recommend the use of unextracted skin tissue. δ15 N values should be obtained from unextracted skin, whereas δ13 C values may be adequately lipid corrected by a mathematical correction.

Trends in tuna carbon isotopes suggest global changes in pelagic phytoplankton communities.

Considerable uncertainty remains over how increasing atmospheric CO2 and anthropogenic climate changes are affecting open-ocean marine ecosystems from phytoplankton to top predators. Biological time series data are thus urgently needed for the world's oceans. Here, we use the carbon stable isotope composition of tuna to provide a first insight into the existence of global trends in complex ecosystem dynamics and changes in the oceanic carbon cycle. From 2000 to 2015, considerable declines in δ13 C values of 0.8‰-2.5‰ were observed across three tuna species sampled globally, with more substantial changes in the Pacific Ocean compared to the Atlantic and Indian Oceans. Tuna recorded not only the Suess effect, that is, fossil fuel-derived and isotopically light carbon being incorporated into marine ecosystems, but also recorded profound changes at the base of marine food webs. We suggest a global shift in phytoplankton community structure, for example, a reduction in 13 C-rich phytoplankton such as diatoms, and/or a change in phytoplankton physiology during this period, although this does not rule out other concomitant changes at higher levels in the food webs. Our study establishes tuna δ13 C values as a candidate essential ocean variable to assess complex ecosystem responses to climate change at regional to global scales and over decadal timescales. Finally, this time series will be invaluable in calibrating and validating global earth system models to project changes in marine biota.

Using experience sampling to examine links between compassion, eudaimonia, and pro-social behavior.

OBJECTIVE: Compassion has been associated with eudaimonia and pro-social behavior, and it has been regarded as a virtue, both historically and cross-culturally. However, the psychological study of compassion has been limited to laboratory settings and/or standard survey assessments. Here, we use an experience sampling method (ESM) to compare naturalistic assessments of compassion with standard assessments, and to examine compassion, its variability, and associations with eudaimonia and pro-social behavior. METHOD: Undergraduate students (n = 200) took a survey that included standard assessments of compassion and eudaimonia. Then, over 4 days, they were repeatedly asked about their level of compassion, eudaimonia, and situational factors within the moments of daily life. Finally, pro-social behavior was tested using the Dual Gamble Task and an opportunity to donate task winnings. RESULTS: Analyses revealed within-person associations between ESM compassion and eudaimonia. ESM compassion also predicted eudaimonia at the next ESM time point. While not impervious to situational factors, considerable consistency was observed in ESM compassion in comparison with eudaimonia. Further, ESM compassion along with eudaimonia predicted donating behavior. Standard assessments did not. CONCLUSIONS: Consistent with virtue theory, some individuals' reports were indicative of a probabilistic tendency toward compassion, and ESM compassion predicted ESM eudaimonia and pro-social behavior toward those in need.

Quality Improvement in Bariatric Surgery: The Impact of Reducing Postoperative Complications on Medicare Payments.

OBJECTIVE: To determine the temporal relationship between reducing surgical complications and costs, using the study population of bariatric surgery. BACKGROUND: Understanding the relationship between quality and costs has significant implications for the business case of investing in performance improvement. An unprecedented focus on safety in bariatric surgery has led to substantial reductions in complication rates over time, making it an ideal patient population in which to examine this relationship. METHODS: We performed a retrospective review of Medicare beneficiaries undergoing bariatric surgery in the years 2005 to 2006 and 2013 to 2014 (total N = 37,329 patients, 562 hospitals). Hospitals were ranked into quintiles based on their degree of improvement in risk and reliability-adjusted 30-day rates of serious complications across the time periods. Multivariable regression was used to calculate corresponding changes in average price-standardized payments for each quintile of hospitals. RESULTS: We found a strong association between reductions in complications and decreased Medicare payments. The top 20% of hospitals had a decrease in average serious complication rate of 7.3% (10.0%-2.7%; P < 0.001) and an average per-patient savings of $4861 (95% confidence interval $3921-5802). Conversely, the bottom 20% of hospitals had smaller decrease in complication rate of 0.8% (4.4% to 3.6%; P < 0.001) and a smaller average savings of $2814 (95% confidence interval $2139-3490). CONCLUSIONS: When analyzing Medicare patients undergoing bariatric surgery, hospitals with the largest reductions in serious postoperative complications had the greatest decrease in per-patient payments. This study demonstrates the potential savings associated with quality improvement in high-risk surgical procedures.

Signals from the south; humpback whales carry messages of Antarctic sea-ice ecosystem variability.

Southern hemisphere humpback whales (Megaptera novaeangliae) rely on summer prey abundance of Antarctic krill (Euphausia superba) to fuel one of the longest-known mammalian migrations on the planet. It is hypothesized that this species, already adapted to endure metabolic extremes, will be one of the first Antarctic consumers to show measurable physiological change in response to fluctuating prey availability in a changing climate; and as such, a powerful sentinel candidate for the Antarctic sea-ice ecosystem. Here, we targeted the sentinel parameters of humpback whale adiposity and diet, using novel, as well as established, chemical and biochemical markers, and assembled a time trend spanning 8 years. We show the synchronous, inter-annual oscillation of two measures of humpback whale adiposity with Southern Ocean environmental variables and climate indices. Furthermore, bulk stable isotope signatures provide clear indication of dietary compensation strategies, or a lower trophic level isotopic change, following years indicated as leaner years for the whales. The observed synchronicity of humpback whale adiposity and dietary markers, with climate patterns in the Southern Ocean, lends strength to the role of humpback whales as powerful Antarctic sea-ice ecosystem sentinels. The work carries significant potential to reform current ecosystem surveillance in the Antarctic region.

Position-specific 13 C/12 C analysis of amino acid carboxyl groups - automated flow-injection analysis based on reaction with ninhydrin.

RATIONALE: The fundamental level of stable isotopic knowledge lies at specific atomic positions within molecules but existing methods of analysis require lengthy off-line preparation to reveal this information. An automated position-specific isotope analysis (PSIA) method is presented to determine the stable carbon isotopic compositions of the carboxyl groups of amino acids (δ13 CCARBOXYL values). This automation makes PSIA measurements easier and routine. METHODS: An existing high-performance liquid chromatography (HPLC) gas handling interface/stable isotope ratio mass spectrometry system was modified by the addition of a post-column derivatisation unit between the HPLC system and the interface. The post-column reaction was optimised to yield CO2 from the carboxyl groups of amino acids by reaction with ninhydrin. RESULTS: The methodology described produced δ13 CCARBOXYL values with typical standard deviations below ±0.1 ‰ and consistent differences (Δ13 CCARBOXYL values) between amino acids over a 1-year period. First estimates are presented for the δ13 CCARBOXYL values of a number of internationally available amino acid reference materials. CONCLUSIONS: The PSIA methodology described provides a further dimension to the stable isotopic characterisation of amino acids at a more detailed level than the bulk or averaged whole-molecule level. When combined with on-line chromatographic separation or off-line fraction collection of protein hydrolysates the technique will offer an automated and routine way to study position-specific carboxyl carbon isotope information for amino acids, enabling more refined isotopic studies of carbon uptake and metabolism.

Feeding strategies for the acquisition of high-quality food sources in stream macroinvertebrates: Collecting, integrating, and mixed feeding.

Aquatic macroinvertebrates play an important functional role in energy transfer in food webs, linking basal food sources to upper trophic levels that include fish, birds, and humans. However, the trophic coupling of nutritional quality between macroinvertebrates and their food sources is still poorly understood. We conducted a field study in subalpine streams in Austria to investigate how the nutritional quality (measured by long-chain polyunsaturated fatty acids, LC-PUFAs) in macroinvertebrates changes relative to their basal food sources. Samples of macroinvertebrates, periphyton, and leaves were collected from 17 streams in July and October 2016 and their fatty acid (FA) composition was analyzed. Periphyton FA varied strongly with time and space, and their trophic effect on macroinvertebrate FA differed among functional feeding groups. The match between periphyton FA and macroinvertebrate FA decreased with increasing trophic levels, but LC-PUFA content increased with each trophic step from periphyton to grazers and finally predators. Macroinvertebrates fed selectively on, assimilated, and/or actively controlled their LC-PUFA, especially eicosapentaenoic acid (EPA, 20 : 5ω3) relative to their basal food sources in the face of spatial and temporal changes. Grazer FA profiles reflected periphyton FA with relatively good fidelity, and especially their EPA feeding strategy was primarily linked to periphyton FA variation across seasons. In contrast, shredders appeared to preferentially assimilate more EPA over other FA, which was determined by the availability of high-quality food over seasons. Predators may more actively control their LC-PUFA distribution with respect to different quality foods and showed less fidelity to the basal FA profiles in plants and prey. Overall, grazers and shredders showed relatively good fidelity to food FA profiles and performed as both "collectors" and "integrators" for LC-PUFA requirements across seasons, while predators at higher trophic levels were more "integrators" with added metabolic complexity leading to somewhat more divergent FA profiles. These results are potentially applicable for other aquatic consumers in freshwater and marine ecosystems.

Barriers to efficiency in robotic surgery: the resident effect.

BACKGROUND: Robotic surgery offers advantages over conventional operative approaches but may also be associated with higher costs and additional risks. Analyzing surgical flow disruptions (FDs), defined as "deviations from the natural progression of an operation," can help target training techniques and identify opportunities for improvement. MATERIALS AND METHODS: Thirty-two robotic surgery operations were observed over a 6-wk period at one 900-bed surgical center. FDs were recorded in detail and classified into one of 11 different categories. Procedure type, robot model, and resident involvement were also recorded. Linear regression analyses were used to evaluate the effects of these parameters on FDs and operative duration. RESULTS: Twenty-one prostatectomies, eight sacrocolpopexies, and three nephrectomies were observed. The mean number of FDs was 48.2 (95% confidence interval [CI] 38.6-54.8 FDs), and mean operative duration was 163 min (95% CI 148-179 min). Each FD added 2.4 min (P = 0.025) to a case's total operative duration. The number and rate of FDs were significantly affected by resident involvement (P = 0.008 and P = 0.006, respectively). Resident cases demonstrated mostly training, equipment, and robot switch FDs, whereas nonresident cases demonstrated mostly equipment, instrument changes, and external factor FDs. CONCLUSIONS: Although the FDs encountered in resident training are more frequent, they may not significantly increase operative duration. Other FDs, such as equipment or external factors, may be more impactful. Limiting these specific FDs should be the focus of performance improvement efforts.