Ruffed lemurs (Varecia variegata and Varecia rubra) are categorized as Critically Endangered on the IUCN Red List, and genetic studies are needed for assessing the conservation value of captive populations. Using 280 mitochondrial DNA (mtDNA) D-loop sequences, we studied the genetic diversity and structure of captive ruffed lemurs in Madagascar, Europe and North America. We found 10 new haplotypes: one from the European captive V. rubra population, three from captive V. variegata subcincta (one from Europe and two from Madagascar) and six from other captive V. variegata in Madagascar. We found low mtDNA genetic diversity in the European and North American captive populations of V. variegata. Several founder individuals shared the same mtDNA haplotype and therefore should not be assumed to be unrelated founders when making breeding recommendations. The captive population in Madagascar has high genetic diversity, including haplotypes not yet identified in wild populations. We determined the probable geographical provenance of founders of captive populations by comparison with previous studies; all reported haplotypes from captive ruffed lemurs were identical to or clustered with haplotypes from wild populations located north of the Mangoro River in Madagascar. Effective conservation strategies for wild populations, with potentially unidentified genetic diversity, should still be considered the priority for conserving ruffed lemurs. However, our results illustrate that the captive population in Madagascar has conservation value as a source of potential release stock for reintroduction or reinforcement projects and that cross-regional transfers within the global captive population could increase the genetic diversity and therefore the conservation value of each regional population.

Prenatal glucocorticoid overexposure causes adult metabolic dysfunction in several species but its effects on adult mitochondrial function remain largely unknown. Using respirometry, this study examined mitochondrial substrate metabolism of fetal and adult ovine biceps femoris (BF) and semitendinosus (ST) muscles after cortisol infusion before birth. Physiological increases in fetal cortisol concentrations pre-term induced muscle- and substrate-specific changes in mitochondrial oxidative phosphorylation capacity in adulthood. These changes were accompanied by muscle-specific alterations in protein content, fibre composition and abundance of the mitochondrial electron transfer system (ETS) complexes. In adult ST, respiration using palmitoyl-carnitine and malate was increased after fetal cortisol treatment but not with other substrate combinations. There were also significant increases in protein content and reductions in the abundance of all four ETS complexes, but not ATP synthase, in the ST of adults receiving cortisol prenatally. In adult BF, intrauterine cortisol treatment had no effect on protein content, respiratory rates, ETS complex abundances or ATP synthase. Activity of citrate synthase, a marker of mitochondrial content, was unaffected by intrauterine treatment in both adult muscles. In the ST but not BF, respiratory rates using all substrate combinations were significantly lower in the adults than fetuses, predominantly in the saline-infused controls. The ontogenic and cortisol-induced changes in mitochondrial function were, therefore, more pronounced in the ST than BF muscle. Collectively, the results show that fetal cortisol overexposure programmes mitochondrial substrate metabolism in specific adult muscles with potential consequences for adult metabolism and energetics.

Despite extensive paleoenvironmental research on the postglacial history of the Kenai Peninsula, Alaska, uncertainties remain regarding the region's deglaciation, vegetation development, and past hydroclimate. To elucidate this complex environmental history, we present new proxy datasets from Hidden and Kelly lakes, located in the eastern Kenai lowlands at the foot of the Kenai Mountains, including sedimentological properties (magnetic susceptibility, organic matter, grain size, and biogenic silica), pollen and macrofossils, diatom assemblages, and diatom oxygen isotopes. We use a simple hydrologic and isotope mass balance model to constrain interpretations of the diatom oxygen isotope data. Results reveal that glacier ice retreated from Hidden Lake's headwaters by ca. 13.1 cal ka BP, and that groundwater was an important component of Kelly Lake's hydrologic budget in the Early Holocene. As the forest developed and the climate became wetter in the Middle to Late Holocene, Kelly Lake reached or exceeded its modern level. In the last ca. 75 years, rising temperature caused rapid changes in biogenic silica content and diatom oxygen isotope values. Our findings demonstrate the utility of mass balance modeling to constrain interpretations of paleolimnologic oxygen isotope data, and that groundwater can exert a strong influence on lake water isotopes, potentially confounding interpretations of regional climate.

From 2014 to 2020, we compiled radiocarbon ages from the lower 48 states, creating a database of more than 100,000 archaeological, geological, and paleontological ages that will be freely available to researchers through the Canadian Archaeological Radiocarbon Database. Here, we discuss the process used to compile ages, general characteristics of the database, and lessons learned from this exercise in “big data” compilation.

Motivated by the desire to understand complex transient behaviour in fluid flows, we study the dynamics of an air bubble driven by the steady motion of a suspending viscous fluid within a Hele-Shaw channel with a centred depth perturbation. Using both experiments and numerical simulations of a depth-averaged model, we investigate the evolution of an initially centred bubble of prescribed volume as a function of flow rate and initial shape. The experiments exhibit a rich variety of organised transient dynamics, involving bubble breakup as well as aggregation and coalescence of interacting neighbouring bubbles. The long-term outcome is either a single bubble or multiple separating bubbles, positioned along the channel in order of increasing velocity. Up to moderate flow rates, the life and fate of the bubble are reproducible and can be categorised by a small number of characteristic behaviours that occur in simply connected regions of the parameter plane. Increasing the flow rate leads to less reproducible time evolutions with increasing sensitivity to initial conditions and perturbations in the channel. Time-dependent numerical simulations that allow for breakup and coalescence are found to reproduce most of the dynamical behaviour observed experimentally, including enhanced sensitivity at high flow rate. An unusual feature of this system is that the set of steady and periodic solutions can change during temporal evolution because both the number of bubbles and their size distribution evolve due to breakup and coalescence events. Calculation of stable and unstable solutions in the single- and two-bubble cases reveals that the transient dynamics is orchestrated by weakly unstable solutions of the system that can appear and disappear as the number of bubbles changes.

Analyses of ancient food webs reveal important paleoecological processes and responses to a range of perturbations throughout Earth's history, such as climate change. These responses can inform our forecasts of future biotic responses to similar perturbations. However, previous analyses of ancient food webs rarely accounted for key differences between modern and ancient community data, particularly selective loss of soft-bodied taxa during fossilization. To consider how fossilization impacts inferences of ancient community structure, we (1) analyzed node-level attributes to identify correlations between ecological roles and fossilization potential and (2) applied selective information loss procedures to food web data for extant systems. We found that selective loss of soft-bodied organisms has predictable effects on the trophic structure of “artificially fossilized” food webs because these organisms occupy unique, consistent food web positions. Fossilized food webs misleadingly appear less stable (i.e., more prone to trophic cascades), with less predation and an overrepresentation of generalist consumers. We also found that ecological differences between soft- and hard-bodied taxa—indicated by distinct positions in modern food webs—are recorded in an early Eocene web, but not in Cambrian webs. This suggests that ecological differences between the groups have existed for ≥48 Myr. Our results indicate that accounting for soft-bodied taxa is vital for accurate depictions of ancient food webs. However, the consistency of information loss trends across the analyzed food webs means it is possible to predict how the selective loss of soft-bodied taxa affects food web metrics, which can permit better modeling of ancient communities.

Advanced imaging techniques are enhancing research capacity focussed on the developmental origins of adult health and disease (DOHaD) hypothesis, and consequently increasing awareness of future health risks across various subareas of DOHaD research themes. Understanding how these advanced imaging techniques in animal models and human population studies can be both additively and synergistically used alongside traditional techniques in DOHaD-focussed laboratories is therefore of great interest. Global experts in advanced imaging techniques congregated at the advanced imaging workshop at the 2019 DOHaD World Congress in Melbourne, Australia. This review summarizes the presentations of new imaging modalities and novel applications to DOHaD research and discussions had by DOHaD researchers that are currently utilizing advanced imaging techniques including MRI, hyperpolarized MRI, ultrasound, and synchrotron-based techniques to aid their DOHaD research focus.

A surface-energy/mass-balance model with an explicit calculation of meltwater refreezing and superimposed ice formation is applied to midre Lovénbreen, Spitsbergen, Svalbard. The model is run with meteorological measurements to represent the present climate, and run with scenarios taken from global climate model predictions based on the IS92a emissions scenario to represent future climates. Model results indicate that superimposed ice accounts for on average 37% of the total net accumulation under present conditions. The model is found to be highly sensitive to changes in the mean annual air temperature and much less sensitive to changes in the total annual precipitation. A 0.5˚C decade–1 temperature increase is predicted to cause an average mass-balance change of –0.43 ma–1, while a 2% decade–1 increase in precipitation will result in only a +0.02 ma–1 change in mass balance. An increase in temperature results in a significant decrease in the size of the accumulation area at midre Lovénbreen and hence a similar decrease in the net volume of superimposed ice. The model predicts, however, that the relative importance of superimposed ice will increase to account for >50% of the total accumulation by 2050. The results show that the refreezing of meltwater and in particular the formation of superimposed ice make an important positive contribution to the mass balance of midre Lovénbreen under present conditions and will play a vital future role in slowing down the response of glacier mass balance to climate change.

On an 11 m firn/ice core from Kongsvegen, Svalbard, we have used dielectric profiling (DEP) to measure electrical properties, and digital photography to measure a core optical stratigraphy (COS) profile. We also used a neutron-scattering probe (NP) to measure a density profile in the borehole from which the core was extracted. The NP- and DEP-derived density profiles were similar, showing large-scale (>30 cm) variation in the gravimetric densities of each core section. Fine-scale features (<10 cm) are well characterized by the COS record and are seen at a slightly lower resolution in both the DEP and NP records, which show increasing smoothing. A combination of the density accuracy of NP and the spatial resolution of COS provides a useful method of evaluating the shallow-density profile of a glacier, improving paleoclimate interpretation, mass-balance measurement and interpretation of radar returns.

Objective: Cervical spine clinical adjacent segment pathology (CASP) has a reported 3% annual incidence and 26% ten-year prevalence. Its pathophysiology remains controversial, whether due to mechanical stress of a fusion segment on adjacent levels or due to patient propensity to develop progressive degenerative change. We investigate this relationship by comparing prevalence of CASP in traumatic and spondylotic patient cohorts. Method: A retrospective review of traumatic cervical spine fusion cases performed by the local group of neurosurgeons from 2004-2008 was completed. Surgery for CASP and presence of radiological adjacent segment pathology (RASP) were identified by telephone and electronic medical record (EMR) review, and compared to those in patients having elective cervical fusion for degenerative disease. Results: There was a higher proportion of males (50/100 vs. 37/46, p<0.001) in the traumatic group. Median age between groups was not significantly different (47 years in the trauma cohort, 50 years in the degenerative cohort; p>0.05). Mean follow-up times were different (6.4 years in the trauma group, 7.1 years in the degenerative group; p<0.01), although this was not thought to be clinically significant. The degenerative group was found to have a significantly higher reoperation rate for CASP (10/100 vs. 0/46, p=0.031, Fisher’s Exact Test), and rate of RASP (20/100 vs. 1/32, p=0.025) Conclusion: This is the only cohort study to our knowledge comparing surgery for CASP in trauma patients to those with degenerative disease. A higher rate of repeat surgery in degenerative disease patients was found. This suggests that CASP is more related to patient factors predisposing to progressive degenerative disease and not increased mechanical stress.

Which parties benefit from open-list (as opposed to closed-list) proportional representation elections? This article shows that a move from closed-list to open-list competition is likely to be more favorable to parties with more internal disagreement on salient issues; this is because voters who might have voted for a unified party under closed lists may be drawn to specific candidates within internally divided parties under open lists. The study provides experimental evidence of this phenomenon in a hypothetical European Parliament election in the UK, in which using an open-list ballot would shift support from UKIP (the Eurosceptic party) to Eurosceptic candidates of the Conservative Party. The findings suggest that open-list ballots could restrict support for parties that primarily mobilize on a single issue.