Identification and management of preoperative anaemia in adults: A British Society for Haematology Guideline update.

This updated British Society for Haematology guideline provides an up-to-date literature review and recommendations regarding the identification and management of preoperative anaemia. This includes guidance on thresholds for the diagnosis of anaemia and the diagnosis and management of iron deficiency in the preoperative context. Guidance on the appropriate use of erythropoiesis-stimulating agents and preoperative transfusion is also provided.

Droughts reshape apex predator space use and intraguild overlap.

Droughts are increasing in frequency and severity globally due to climate change, leading to changes in resource availability that may have cascading effects on animal ecology. Resource availability is a key driver of animal space use, which in turn influences interspecific interactions like intraguild competition. Understanding how climate-induced changes in resource availability influence animal space use, and how species-specific responses scale up to affect intraguild dynamics, is necessary for predicting broader community-level responses to climatic changes. Although several studies have demonstrated the ecological impacts of drought, the behavioural responses of individuals that scale up to these broader-scale effects are not well known, particularly among animals in top trophic levels like large carnivores. Furthermore, we currently lack understanding of how the impacts of climate variability on individual carnivore behaviour are linked to intraguild dynamics, in part because multi-species datasets collected at timescales relevant to climatic changes are rare. Using 11 years of GPS data from four sympatric large carnivore species in southern Africa-lions (Panthera leo), leopards (Panthera pardus), African wild dogs (Lycaon pictus) and cheetahs (Acinonyx jubatus)-spanning 4 severe drought events, we test whether drought conditions impact (1) large carnivore space use, (2) broad-scale intraguild spatial overlap and (3) fine-scale intraguild interactions. Drought conditions expanded space use across species, with carnivores increasing their monthly home range sizes by 35% (wild dogs) to 66% (leopards). Drought conditions increased the amount of spatial overlap between lions and subordinate felids (cheetahs and leopards) by up to 119%, but only lion-cheetah encounter rates were affected by these changes, declining in response to drought. Our findings reveal that drought has a clear signature on the space use of multiple sympatric large carnivore species, which can alter spatiotemporal partitioning between competing species. Our study thereby illuminates the links between environmental change, animal behaviour and intraguild dynamics. While fine-scale avoidance strategies may facilitate intraguild coexistence during periodic droughts, large carnivore conservation may require considerable expansion of protected areas or revised human-carnivore coexistence strategies to accommodate the likely long-term increased space demands of large carnivores under projected increases in drought intensity.

Remarkable muscles, remarkable locomotion in desert-dwelling wildebeest.

Large mammals that live in arid and/or desert environments can cope with seasonal and local variations in rainfall, food and climate1 by moving long distances, often without reliable water or food en route. The capacity of an animal for this long-distance travel is substantially dependent on the rate of energy utilization and thus heat production during locomotion-the cost of transport2-4. The terrestrial cost of transport is much higher than for flying (7.5 times) and swimming (20 times)4. Terrestrial migrants are usually large1-3 with anatomical specializations for economical locomotion5-9, because the cost of transport reduces with increasing size and limb length5-7. Here we used GPS-tracking collars10 with movement and environmental sensors to show that blue wildebeest (Connochaetes taurinus, 220 kg) that live in a hot arid environment in Northern Botswana walked up to 80 km over five days without drinking. They predominantly travelled during the day and locomotion appeared to be unaffected by temperature and humidity, although some behavioural thermoregulation was apparent. We measured power and efficiency of work production (mechanical work and heat production) during cyclic contractions of intact muscle biopsies from the forelimb flexor carpi ulnaris of wildebeest and domestic cows (Bos taurus, 760 kg), a comparable but relatively sedentary ruminant. The energetic costs of isometric contraction (activation and force generation) in wildebeest and cows were similar to published values for smaller mammals. Wildebeest muscle was substantially more efficient (62.6%) than the same muscle from much larger cows (41.8%) and comparable measurements that were obtained from smaller mammals (mouse (34%)11 and rabbit (27%)). We used the direct energetic measurements on intact muscle fibres to model the contribution of high working efficiency of wildebeest muscle to minimizing thermoregulatory challenges during their long migrations under hot arid conditions.

Biomechanics of predator-prey arms race in lion, zebra, cheetah and impala.

The fastest and most manoeuvrable terrestrial animals are found in savannah habitats, where predators chase and capture running prey. Hunt outcome and success rate are critical to survival, so both predator and prey should evolve to be faster and/or more manoeuvrable. Here we compare locomotor characteristics in two pursuit predator-prey pairs, lion-zebra and cheetah-impala, in their natural savannah habitat in Botswana. We show that although cheetahs and impalas were universally more athletic than lions and zebras in terms of speed, acceleration and turning, within each predator-prey pair, the predators had 20% higher muscle fibre power than prey, 37% greater acceleration and 72% greater deceleration capacity than their prey. We simulated hunt dynamics with these data and showed that hunts at lower speeds enable prey to use their maximum manoeuvring capacity and favour prey survival, and that the predator needs to be more athletic than its prey to sustain a viable success rate.

Fragility Index Analysis of the 2018 Clinical Practice Guidelines on Tranexamic Acid Use in Total Joint Arthroplasty.

BACKGROUND: The 2018 American Association of Hip and Knee Surgeons clinical practice guideline (CPG) 'tranexamic acid use in total joint arthroplasty' evaluated the efficacy and safety of tranexamic acid in primary total joint arthroplasty. The following review assessed the statistical fragility of the randomized controlled trial (RCT) outcomes on which the CPG recommendations were based using a fragility analysis. METHODS: All dichotomous outcomes from the RCTs used to guide the CPG from its associated network, and direct meta-analyses were analyzed. Fragility and reverse fragility indices (FI and rFI) and quotients were calculated for each outcome. The mean indices and quotients were calculated for each guideline question, outcome category, and comparison of tranexamic dose, formulation, and administration timing. RESULTS: This review evaluated 403 dichotomous outcomes on transfusion and complication rates associated with tranexamic acid (TXA) administration. The mean FI of significant outcomes of the CPG was 5.23, and the mean rFI of nonsignificant outcomes was 5.80. Outcomes assessing complication rates had a mean rFI of 6.48. Most outcomes on transfusion in categories comparing TXA to placebo administration had higher mean FIs than rFIs, and all outcomes comparing transfusion risk associated with different TXA formulations and doses had higher mean rFIs than FI or no associated significant outcomes. CONCLUSIONS: The rFI and FIs calculated for this CPG are comparable to or higher than mean values reported across orthopaedic literature, indicating the relative statistical stability of its included outcomes. As we learn more about fragility analyses and their potential applications, this type of statistical analysis shows promise as a useful tool to incorporate into future guidelines to assess the quality of RCTs and evaluate the strength of recommendations.

Engineered algal systems for the treatment of anaerobic digestate: A meta-analysis.

The objective of this review was to provide quantitative insights into algal growth and nutrient removal in anaerobic digestate. To synthesize the relevant literature, a meta-analysis was conducted using data from 58 articles to elucidate key factors that impact algal biomass productivity and nutrient removal from anaerobic digestate. On average, algal biomass productivity in anaerobic digestate was significantly lower than that in synthetic control media (p < 0.05) but large variation in productivity was observed. A mixed-effects multiple regression model across study revealed that biological or chemical pretreatment of digestate significantly increase productivity (p < 0.001). In contrast, the commonly used practice of digestate dilution was not a significant factor in the model. High initial total ammonia nitrogen suppressed algal growth (p = 0.036) whereas initial total phosphorus concentration, digestate sterilization, CO2 supplementation, and temperature were not statistically significant factors. Higher growth corresponded with significantly higher NH4-N and phosphorus removal with a linear relationship of 6.4 mg NH4-N and 0.73 mg P removed per 100 mg of algal biomass growth (p < 0.001). The literature suggests that suboptimal algal growth in anaerobic digestate could be due to factors such as turbidity, high free ammonia, and residual organic compounds. This analysis shows that non-dilution approaches, such as biological or chemical pretreatment, for alleviating algal inhibition are recommended for algal digestate treatment systems.

Increasing ambient temperatures trigger shifts in activity patterns and temporal partitioning in a large carnivore guild.

Shifts in species' interactions are implicated as an important proximate cause underpinning climate-change-related extinction. However, there is little empirical evidence on the pathways through which climate conditions, such as ambient temperature, impact community dynamics. The timing of activities is a widespread behavioural adaptation to environmental variability, and temporal partitioning is a key mechanism that facilitates coexistence, especially within large carnivore communities. We investigated temperature impacts on community dynamics through its influence on the diel activity of, and temporal partitioning amongst, four sympatric species of African large carnivores: lions (Panthera leo), leopards (Panthera pardus), cheetahs (Acinonyx jubatus) and African wild dogs (Lycaon pictus). Activity of all species was shaped by a combination of light availability and temperature, with most species becoming more nocturnal and decreasing activity levels with increasing temperatures. A nocturnal shift was most pronounced in cheetahs, the most diurnal species during median temperatures. This shift increased temporal overlap between cheetahs and other carnivore species by up to 15.92%, highlighting the importance of considering the responses of interacting sympatric species when inferring climate impacts on ecosystems. Our study provides evidence that temperature can significantly affect temporal partitioning within a carnivore guild by generating asymmetrical behavioural responses amongst functionally similar species.

Positive and negative impacts of flue gas desulfurization (FGD) gypsum on water quality.

Flue gas desulfurization (FGD) gypsum, a by-product of carbon-based energy sources, has typically been incorporated as a component of concrete mixes and wallboard and beneficially used as an agricultural amendment to enhance terrestrial crop production and improve the quality of runoff. These various uses for the by-product aid in reducing the amount that is ultimately landfilled. Limited studies have investigated its benefits when used directly in aquatic settings, such as ponds and lakes, to increase hardness and potentially mitigate eutrophication. A 36-day field mesocosm experiment tested a larger range of FGD gypsum concentrations (500-2000 mg/L) than those previously tested in the literature to investigate its desired and potentially undesired impacts on water quality, including the algal community. High FGD gypsum concentrations, 1000 and 2000 mg/L, were found to have more undesired impacts than the 500 mg/L treatment, including an initial spike in cyanobacteria, a decrease in total zooplankton abundance, and an increase in certain trace metals in the highest treatment. Ultimately, the 500 mg/L FGD gypsum treatment was found to have fewer undesired impacts while still resulting in significant desired effects, including those on hardness and pH, as well as moderate reductions in algal abundance. This experiment provides a better understanding of the effects of FGD gypsum when directly used in an aquatic setting, determines an optimal dose for future field experiments, and helps provide the groundwork for developing an upper threshold on FGD gypsum so as to not have the negative effects outweigh the positive.

Local adaptation mediates direct and indirect effects of multiple stressors on consumer fitness.

Anthropogenic impacts are expected to increase the co-occurrence of stressors that can fundamentally alter ecosystem structure and function. To cope with stress, many organisms locally adapt, but how such adaptations affect the ability of an organism to manage co-occurring stressors is not well understood. In aquatic ecosystems, elevated temperatures and harmful algal blooms are common co-stressors. To better understand the role and potential trade-offs of local adaptations for mitigating the effects of stressors, Daphnia pulicaria genotypes that varied in their ability to consume toxic cyanobacteria prey (i.e., three tolerant and three sensitive) were exposed to five diets that included combinations of toxic cyanobacteria, Microcystis aeruginosa, and a green alga, Ankistrodesmus falcatus, under two temperatures (20 °C vs. 28 °C). A path analysis was conducted to understand how local adaptations affect energy allocation to intermediate life history traits (i.e., somatic growth, fecundity, survival) that maximize Daphnia fitness (i.e., population growth rate). Results from the 10-day study show that tolerant Daphnia genotypes had higher fitness than sensitive genotypes regardless of diet or temperature treatment, suggesting toxic cyanobacteria tolerance did not cause a decrease in fitness in the absence of cyanobacteria or under elevated temperatures. Results from the path analysis demonstrated that toxic cyanobacteria had a stronger effect on life history traits than temperature and that population growth rate was mainly constrained by reduced fecundity. These findings suggest that local adaptations to toxic cyanobacteria and elevated temperatures are synergistic, leading to higher survivorship of cyanobacteria-tolerant genotypes during summer cyanobacterial bloom events.

Perioperative Blood Management in Total Joint Arthroplasty.

Preoperative anemia is an established risk factor for complications following total joint arthroplasty. Postoperative anemia can be managed with allogeneic blood transfusion, but this has inherent risks. A thorough preoperative workup can help to diagnose anemia and optimize these patients for surgery to minimize the need for postoperative transfusion. Perioperatively, the amount of blood loss can be minimized by using hypotensive anesthetic techniques and administering antifibrinolytic agents. Last, in the event that allogeneic blood transfusion is still required, strict transfusion guidelines should be followed. Evidence-based interventions for preoperative, perioperative, and postoperative blood management in total joint arthroplasty will be reviewed.

Can correlational analyses help determine the drivers of microcystin occurrence in freshwater ecosystems? A meta-analysis of microcystin and associated water quality parameters.

Microcystin (MC) is a toxic secondary metabolite produced by select cyanobacteria that threatens aquatic and terrestrial organisms over a diverse range of freshwater systems. To assess the relationship between environmental parameters and MC, researchers frequently utilize correlational analyses. This statistical methodology has proved useful when summarizing complex water quality monitoring datasets, but the correlations between select parameters and MC have been documented to vary widely across studies and systems. Such variation within the peer-reviewed literature leaves uncertainty for resource managers when developing a MC monitoring program. The objective of this research is to determine if correlational analyses between environmental parameters and MC are helpful to resource managers desiring to understand the drivers of MC. Environmental (i.e., physical, chemical, and biological) and MC correlation data were retrieved from an estimated 2,643 waterbodies (largely from the north temperate region) and synthesized using a Fisher's z meta-analysis. Common water quality parameters, such as chlorophyll, temperature, and pH, were positively correlated with MC, while transparency was negatively correlated. Interestingly, 12 of the 15 studied nitrogen parameters, including total nitrogen, were not significantly correlated with MC. In contrast, three of the four studied phosphorus parameters, including total phosphorus, were positively related to MC. Results from this synthesis quantitatively reinforces the usefulness of commonly measured environmental parameters to monitor for conditions related to MC occurrence; however, correlational analyses by themselves are often ineffective and considering what role a parameter plays in the ecology of cyanobacterial blooms in addition to MC production is vital.

Fatty acid amide hydrolase is lower in young cannabis users.

We have recently shown that levels of fatty acid amide hydrolase (FAAH), the enzyme that metabolizes the endocannabinoid anandamide, are lower in the brains of adult cannabis users (CUs) (34 ± 11 years of age), tested during early abstinence. Here, we examine replication of the lower FAAH levels in a separate, younger cohort (23 ± 5 years of age). Eighteen healthy volunteers (HVs) and fourteen CUs underwent a positron emission tomography scan using the FAAH radioligand [11 C]CURB. Regional [11 C]CURB binding was calculated using an irreversible two-tissue compartment model with a metabolite-corrected arterial plasma input function. The FAAH C385A genetic polymorphism (rs324420) was included as a covariate. All CUs underwent a urine screen to confirm recent cannabis use and had serum cannabinoids measured. One CU screened negative for cannabinoids via serum and was removed from analysis. All HVs reported less than five lifetime cannabis exposures more than a month prior to study initiation. There was a significant effect of group (F1,26 = 4.31; P = .048) when two A/A (rs324420) HVs were removed from analysis to match the genotype of the CU group (n = 16 HVs, n = 13 CUs). Overall, [11 C]CURB λk3 was 12% lower in CU compared with HV. Exploratory correlations showed that lower brain [11 C]CURB binding was related to greater use of cannabis throughout the past year. We confirmed our previous report and extended these findings by detecting lower [11 C]CURB binding in a younger cohort with less cumulative cannabis exposure.

Sequencing Disparity in the Genomic Era.

Advances in sequencing technology have resulted in the expectation that genomic studies will become more representative of organismal diversity. To test this expectation, we explored species representation of nonhuman eukaryotes in the Sequence Read Archive. Though species richness has been increasing steadily, species evenness is decreasing over time. Moreover, the top 1% most studied organisms increasingly represent a larger proportion of total experiments, demonstrating growing bias in favor of a small minority of species. To better understand molecular processes and patterns, genomic studies should reverse current trends by adopting more comparative approaches.

There and back again - a zebra's tale.

Animals need to navigate between resources such as water, food and shelter, and how they achieve this is likely to vary with species. Here, using high-accuracy GPS data, we studied repeated journeys made by wild plains zebra (Equus quagga) through a naturally vegetated environment to explore whether they consistently follow the same route through the area or whether they use a range of routes to reach their goal. We used a model to distinguish and quantify these two possibilities and show that our observations are consistent with the use of multiple routes. Our model performs better than assuming a uniform angular distribution of trajectories. The typical separation of the routes was found to be small (1.96 m), while the scale at which neighbouring trajectories are informative to direction of travel was found to be large (with a confidence interval of 1.19-26.4 m). Our observations are consistent with the hypothesis that zebra are able to navigate without having to return to previously used routes, instead using numerous different routes of similar trajectories.

There and back again - a zebra's tale.

Animals need to navigate between resources such as water, food and shelter and how they achieve this is likely to vary with species. Here, using high accuracy GPS data, we study repeated journeys made by wild zebra (Equus quagga) through a naturally vegetated environment to explore whether they consistently follow the same route through the area or whether they use a range of routes to reach their goal. We use a model to distinguish and quantify these two possibilities and show that our observations are consistent with the use of multiple routes. Our model performs better than assuming uniform angular distribution of trajectories. The typical separation of the routes was found to be small (1.96 m), while the scale at which neighboring trajectories are informative to direction of travel was found to be large (with a confidence interval of (1.19, 26.4) m). Our observations are consistent with the hypothesis that zebra are able to navigate without having to return to previously used routes, instead using numerous different routes of similar trajectories.

Artificial mass loading disrupts stable social order in pigeon dominance hierarchies.

Dominance hierarchies confer benefits to group members by decreasing the incidences of physical conflict, but may result in certain lower ranked individuals consistently missing out on access to resources. Here, we report a linear dominance hierarchy remaining stable over time in a closed population of birds. We show that this stability can be disrupted, however, by the artificial mass loading of birds that typically comprise the bottom 50% of the hierarchy. Mass loading causes these low-ranked birds to immediately become more aggressive and rise-up the dominance hierarchy; however, this effect was only evident in males and was absent in females. Removal of the artificial mass causes the hierarchy to return to its previous structure. This interruption of a stable hierarchy implies a strong direct link between body mass and social behaviour and suggests that an individual's personality can be altered by the artificial manipulation of body mass.

The global Microcystis interactome.

Bacteria play key roles in the function and diversity of aquatic systems, but aside from study of specific bloom systems, little is known about the diversity or biogeography of bacteria associated with harmful cyanobacterial blooms (cyanoHABs). CyanoHAB species are known to shape bacterial community composition and to rely on functions provided by the associated bacteria, leading to the hypothesized cyanoHAB interactome, a coevolved community of synergistic and interacting bacteria species, each necessary for the success of the others. Here, we surveyed the microbiome associated with Microcystis aeruginosa during blooms in 12 lakes spanning four continents as an initial test of the hypothesized Microcystis interactome. We predicted that microbiome composition and functional potential would be similar across blooms globally. Our results, as revealed by 16S rRNA sequence similarity, indicate that M. aeruginosa is cosmopolitan in lakes across a 280° longitudinal and 90° latitudinal gradient. The microbiome communities were represented by a wide range of operational taxonomic units and relative abundances. Highly abundant taxa were more related and shared across most sites and did not vary with geographic distance, thus, like Microcystis, revealing no evidence for dispersal limitation. High phylogenetic relatedness, both within and across lakes, indicates that microbiome bacteria with similar functional potential were associated with all blooms. While Microcystis and the microbiome bacteria shared many genes, whole-community metagenomic analysis revealed a suite of biochemical pathways that could be considered complementary. Our results demonstrate a high degree of similarity across global Microcystis blooms, thereby providing initial support for the hypothesized Microcystis interactome.

Upwash exploitation and downwash avoidance by flap phasing in ibis formation flight.

Many species travel in highly organized groups. The most quoted function of these configurations is to reduce energy expenditure and enhance locomotor performance of individuals in the assemblage. The distinctive V formation of bird flocks has long intrigued researchers and continues to attract both scientific and popular attention. The well-held belief is that such aggregations give an energetic benefit for those birds that are flying behind and to one side of another bird through using the regions of upwash generated by the wings of the preceding bird, although a definitive account of the aerodynamic implications of these formations has remained elusive. Here we show that individuals of northern bald ibises (Geronticus eremita) flying in a V flock position themselves in aerodynamically optimum positions, in that they agree with theoretical aerodynamic predictions. Furthermore, we demonstrate that birds show wingtip path coherence when flying in V positions, flapping spatially in phase and thus enabling upwash capture to be maximized throughout the entire flap cycle. In contrast, when birds fly immediately behind another bird--in a streamwise position--there is no wingtip path coherence; the wing-beats are in spatial anti-phase. This could potentially reduce the adverse effects of downwash for the following bird. These aerodynamic accomplishments were previously not thought possible for birds because of the complex flight dynamics and sensory feedback that would be required to perform such a feat. We conclude that the intricate mechanisms involved in V formation flight indicate awareness of the spatial wake structures of nearby flock-mates, and remarkable ability either to sense or predict it. We suggest that birds in V formation have phasing strategies to cope with the dynamic wakes produced by flapping wings.

Stress-induced cortical dopamine response is altered in subjects at clinical high risk for psychosis using cannabis.

Stress and cannabis use are risk factors for the development of psychosis. We have previously shown that subjects at clinical high risk for psychosis (CHR) exhibit a higher striatal dopamine response to stress compared with healthy volunteers (HV), with chronic cannabis use blunting this response. However, it is unknown if this abnormal dopamine response extends to the prefrontal cortex (PFC). Here, we investigated dorsolateral PFC (dlPFC) and medial PFC (mPFC) dopamine release using [11 C]FLB457 positron emission tomography (PET) and a validated stress task. Thirty-three participants completed two PET scans (14 CHR without cannabis use, eight CHR regular cannabis users [CHR-CUs] and 11 HV) while performing a Sensory Motor Control Task (control scan) and the Montreal Imaging Stress Task (stress scan). Stress-induced dopamine release (ΔBPND ) was defined as percent change in D2/3 receptor binding potential between both scans using a novel correction for injected mass of [11 C]FLB457. ΔBPND was significantly different between groups in mPFC (F(2,30) = 5.40, .010), with CHR-CUs exhibiting lower ΔBPND compared with CHR (.008). Similarly, salivary cortisol response (ΔAUCI ) was significantly lower in CHR-CU compared with CHR (F(2,29) = 5.08, .013; post hoc .018) and positively associated with ΔBPND . Furthermore, CHR-CUs had higher attenuated psychotic symptoms than CHR following the stress task, which were negatively associated with ΔBPND . Length of cannabis use was negatively associated with ΔBPND in mPFC when controlling for current cannabis use. Given the global trend to legalize cannabis, this study is important as it highlights the effects of regular cannabis use on cortical dopamine function in high-risk youth.

MYONECROSIS AND DEATH DUE TO PRESUMED MICROCYSTIN TOXICOSIS IN AMERICAN WHITE PELICANS (PELECANUS ERYTHRORHYNCOS).

Over a period of 5 mo, seven out of eight American white pelicans (Pelecanus erythrorhynchos) housed on a spring-fed pond at a zoo died or were euthanized. Clinical signs included inability to stand, anorexia, and weight loss. Clinicopathologic findings included heterophilic leukocytosis and elevated creatine kinase and aspartate aminotransferase. Histopathologic findings on all pelicans demonstrated severe, chronic, diffuse rhabdomyofiber degeneration and necrosis, making vitamin E deficiency a differential diagnosis despite routine supplementation. Based on tissue and pond water assays for the cyanobacterial toxin, microcystin, toxicosis is suspected as the inciting cause of death in these cases. We hypothesize that vitamin E exhaustion and resultant rhabdomyodegeneration and cardiomyopathy were sequelae to this toxicosis.