Carry-over effects of seasonal migration on reproductive success through breeding site retention in a partially migratory bird.

Understanding the maintenance and dynamics of phenotypic polymorphisms requires unpicking key ecological mechanisms shaping the fitness costs and benefits of expressing alternative phenotypes, generating selection. Seasonal migration versus year-round residence expressed in partially migratory populations represents one common polymorphism that can experience strong selection through differential reproductive success. Yet, key hypothesised pathways that could generate such selection remain to be empirically tested. One hypothesis is that migratory tactics affect subsequent reproductive success through carry-over effects on breeding site retention and resulting breeding dispersal. By remaining in breeding areas all year round, residents could retain their preferred breeding site between years, and consequently have higher reproductive success. Conversely, migrants that escape harsh non-breeding season conditions could return in better condition, with high resource holding potential, and outcompete residents to retain their site. Such effects could further depend on migration timing and vary between years. Yet, such pathways have not been quantified, precluding empirical parameterisation of partial migration theory. We used 4 years of breeding and non-breeding season data from partially migratory European shags (Gulosus aristotelis) to test whether the three most frequent migratory tactics in this population (full resident, early migrant departing soon after breeding, and late migrant departing in late autumn) differed in their breeding site retention; whether site retention predicted reproductive success; and hence whether effects of migratory tactic on reproductive success were explicable through site retention. Overall, residents were much more likely to retain their breeding site between years than both early and late migrants, and site retention was associated with increased reproductive success. Yet, these effects varied somewhat among years: late migrants were always least likely to retain their site but had variable relative reproductive success. Path analyses revealed that effects of migratory tactic on reproductive success were only partly attributable to breeding site retention. These results indicate that multiple mechanisms underlie reproductive selection on migratory tactics, potentially contributing to maintaining behavioural polymorphisms. Yet, the clear associations between migratory tactics and local breeding dispersal reveal that these movements can be strongly interlinked across seasons, shaping overall spatioseasonal dynamics in partially migratory systems.

Preexercise intermittent passive stretching and vascular function after treadmill exercise.

Acute aerobic exercise stress is associated with decreased endothelial function that may increase the likelihood of an acute cardiovascular event. Passive stretch (PS) elicits improvements in vascular function, but whether PS can be performed before exercise to prevent declines in vascular function remains unknown. This strategy could be directly applicable in populations that may not be able to perform dynamic exercise. We hypothesized that preexercise PS would provide better vascular resilience after treadmill exercise. Sixteen healthy college-aged males and females participated in a single laboratory visit and underwent testing to assess micro- and macrovascular function. Participants were randomized into either PS group or sham control group. Intermittent calf PS was performed by having the foot in a splinting device for a 5-min stretch and 5-min relaxation, repeated four times. Then, a staged V̇o2 peak test was performed and 65% V̇o2 peak calculated for subjects to run at for 30 min. Near-infrared spectroscopy-derived microvascular responsiveness was preserved with the PS group [(pre: 0.53 ± 0.009%/s) (post: 0.56 ± 0.012%/s; P = 0.55)]. However, there was a significant reduction in the sham control group [(pre: 0.67 ± 0.010%/s) (post: 0.51 ± 0.007%/s; P = 0.05)] after treadmill exercise. Flow-mediated vasodilation (FMD) of the popliteal artery showed similar responses. In the PS group, FMD [(pre: 7.23 ± 0.74%) (post: 5.86 ± 1.01%; P = 0.27)] did not significantly decline after exercise. In the sham control group, FMD [(pre: 8.69 ± 0.72%) (post: 5.24 ± 1.24%; P < 0.001)] was significantly reduced after treadmill exercise. Vascular function may be more resilient if intermittent PS is performed before moderate-intensity exercise and, importantly, can be performed by most individuals.NEW & NOTEWORTHY We demonstrate for the first time that popliteal artery and gastrocnemius microvascular responsiveness after acute aerobic exercise are reduced. The decline in vascular function was mitigated in those who performed intermittent passive stretching before the exercise bouts. Collectively, these findings suggest that intermittent passive stretching is a novel method to increase vascular resiliency before aerobic activity.

Subcoracoid acromioclavicular joint dislocation (Rockwood type VI) sustained in motorcycle crash: A case report.

We present the case of a young male who sustained a rare acromioclavicular joint (ACJ) injury during a road traffic accident. A left-sided ACJ injury was identified on plain radiographs fourteen days following a motorcycling accident during which significant distracting injuries were sustained. Owing to persistent shoulder pain during awake tertiary surveillance, repeat shoulder plain radiographs were obtained, along with re-examination of the patient's index computed tomography (CT) shoulder imaging, indicating a grade VI left-sided acromioclavicular subluxation. The patient underwent operative management of the above injury at three weeks, with initial examination under anesthetic revealing a stiff shoulder joint significantly limited external rotation requiring extensive release of fibrosis. The left ACJ was reduced under anesthesia, being temporarily secured with Kirschner wire insertion. A Synthes locking distal tibial "L" plate was contoured and applied across the AC joint, and secured with locking screws. Intensive post-operative physiotherapy resulted in an significantly improved post-operative range of motion in the patient's left shoulder. Acromioclavicular joint injuries, commonly shortened to ACJ injuries, are most regularly traumatic in etiology, ranging in severity from mild sprain to complete joint disruption. ACJ injuries are classified according to the position of the clavicle with respect to the acromion and coracoid. The above case highlights the requirement for comprehensive tertiary surveillance of trauma patients both pre and postextubation, in order to identify such injuries that may require prompt surgical management in order to restore range of motion and function in affected joints.

Integrating advances in population and evolutionary ecology with conservation strategy through long-term studies of red-billed choughs.

Conceptual and methodological advances in population and evolutionary ecology are often pursued with the ambition that they will help identify demographic, ecological and genetic constraints on population growth rate (λ), and ultimately facilitate evidence-based conservation. However, such advances are often decoupled from conservation practice, impeding translation of scientific understanding into effective conservation and of conservation-motivated research into wider conceptual understanding. We summarise key outcomes from long-term studies of a red-billed chough Pyrrhocorax pyrrhocorax population of conservation concern, where we proactively aimed to achieve the dual and interacting objectives of advancing population and evolutionary ecology and advancing effective conservation. Estimation of means, variances and covariances in key vital rates from individual-based demographic data identified temporal and spatial variation in subadult survival as key constraints on λ, and simultaneously provided new insights into how vital rates can vary as functions of demographic structure, natal conditions and parental life history. Targeted analyses showed that first-year survival increased with prey abundance, implying that food limitation may constrain λ. First-year survival then decreased dramatically, threatening population viability and prompting emergency supplementary feeding interventions. Detailed evaluations suggested that the interventions successfully increased first-year survival in some years and additionally increased adult survival and successful reproduction, thereby feeding back to inform intervention refinements and understanding of complex ecological constraints on λ. Genetic analyses revealed novel evidence of expression of a lethal recessive allele, and demonstrated how critically small effective population size can arise, thereby increasing inbreeding and loss of genetic variation. Population viability analyses parameterised with all available demographic and genetic data showed how ecological and genetic constraints can interact to limit population viability, and identified ecological management as of primacy over genetic management to ensure short-term persistence of the focal population. This case study demonstrates a full iteration through the sequence of primary science, evidence-based intervention, quantitative evaluation and feedback that is advocated in conservation science but still infrequently achieved. It thereby illustrates how pure science advances informed conservation actions to ensure the (short-term) stability of the target population, and how conservation-motivated analyses fed back to advance fundamental understanding of population processes.

The impact of the definition of preeclampsia on disease diagnosis and outcomes: a retrospective cohort study.

BACKGROUND: The diagnostic criteria for preeclampsia have evolved from the traditional definition of de novo hypertension and proteinuria to a broader definition of hypertension with evidence of end-organ dysfunction. Although this change is endorsed by various societies such as the International Society for the Study of Hypertension in Pregnancy and the American College of Obstetricians and Gynecologists, there remains controversy with regard to the implementation of broader definitions and the most appropriate definition of end-organ dysfunction. OBJECTIVE: This study aimed to assess the impact of different diagnostic criteria for preeclampsia on rates of disease diagnosis, disease severity, and adverse outcomes and to identify associations between each component of the different diagnostic criteria and adverse pregnancy outcomes. STUDY DESIGN: We performed a retrospective cohort study of singleton pregnancies at Monash Health between January 1, 2016 and July 31, 2018. Within this population, all cases of gestational hypertension and preeclampsia were reclassified according to the International Society for the Study of Hypertension in Pregnancy 2001, American College of Obstetricians and Gynecologists 2018, and International Society for the Study of Hypertension in Pregnancy 2018 criteria. Differences in incidence of preeclampsia and maternal and perinatal outcomes were compared between the International Society for the Study of Hypertension in Pregnancy 2001 group and the extra cases identified by American College of Obstetricians and Gynecologists 2018 and International Society for the Study of Hypertension in Pregnancy 2018. Outcomes assessed included biochemical markers of preeclampsia, a composite of adverse maternal outcomes, and a composite of adverse perinatal outcomes. Multiple logistic regression analysis was also performed to assess each component of the American College of Obstetricians and Gynecologists 2018 and International Society for the Study of Hypertension in Pregnancy 2018 criteria and their associations with adverse maternal and perinatal outcomes. RESULTS: Of 22,094 pregnancies, 751 (3.4%) women had preeclampsia as defined by any of the 3 criteria. Compared with International Society for the Study of Hypertension in Pregnancy 2001, the American College of Obstetricians and Gynecologists 2018 criteria identified an extra 42 women (n=654 vs n=696, 6.4% relative increase) with preeclampsia, and International Society for the Study of Hypertension in Pregnancy 2018 identified an extra 97 women (n=654 vs n=751, 14.8% relative increase). The additional women identified by International Society for the Study of Hypertension in Pregnancy 2018 exhibited a milder form of disease with lower rates of severe hypertension (62.4% vs 44.3%; P<.01) and magnesium sulfate use (11.9% vs 4.1%; P<.05) and a trend toward lower rates of adverse maternal outcomes (9.8% vs 4.1%). These women also delivered at a later gestation, and their babies had a lower number of neonatal intensive care unit admissions and adverse perinatal outcomes. Objective features such as fetal growth restriction, thrombocytopenia, renal and liver impairment, and proteinuria were associated with an increased risk of adverse maternal and perinatal outcomes, whereas subjective neurologic features demonstrated poorer associations. CONCLUSION: Implementation of broader definitions of preeclampsia will result in an increased incidence of disease diagnosis. However, because women who exclusively fulfill the new criteria have a milder phenotype of the disease, it remains uncertain whether this will translate to improved outcomes.

Among-individual and within-individual variation in seasonal migration covaries with subsequent reproductive success in a partially migratory bird.

Within-individual and among-individual variation in expression of key environmentally sensitive traits, and associated variation in fitness components occurring within and between years, determine the extents of phenotypic plasticity and selection and shape population responses to changing environments. Reversible seasonal migration is one key trait that directly mediates spatial escape from seasonally deteriorating environments, causing spatio-seasonal population dynamics. Yet, within-individual and among-individual variation in seasonal migration versus residence, and dynamic associations with subsequent reproductive success, have not been fully quantified. We used novel capture-mark-recapture mixture models to assign individual European shags (Phalacrocorax aristotelis) to 'resident', 'early migrant', or 'late migrant' strategies in two consecutive years, using year-round local resightings. We demonstrate substantial among-individual variation in strategy within years, and directional within-individual change between years. Furthermore, subsequent reproductive success varied substantially among strategies, and relationships differed between years; residents and late migrants had highest success in the 2 years, respectively, matching the years in which these strategies were most frequently expressed. These results imply that migratory strategies can experience fluctuating reproductive selection, and that flexible expression of migration can be partially aligned with reproductive outcomes. Plastic seasonal migration could then potentially contribute to adaptive population responses to currently changing forms of environmental seasonality.