Object manufacture based on a memorized template: Goffin's cockatoos attend to different model features.

Although several nonhuman animals have the ability to recognize and match templates in computerized tasks, we know little about their ability to recall and then physically manufacture specific features of mental templates. Across three experiments, Goffin cockatoos (Cacatua goffiniana), a species that can use tools in captivity, were exposed to two pre-made template objects, varying in either colour, size (long or short) or shape (I or L-shaped), where only one template was rewarded. Birds were then given the opportunity to manufacture versions of these objects themselves. We found that all birds carved paper strips from the same colour material as the rewarded template, and half were also able to match the size of a template (long and short). This occurred despite the template being absent at test and birds being rewarded at random. However, we found no evidence that cockatoos could carve L-shaped pieces after learning that L-shaped templates were rewarded, though their manufactured strips were wider than in previous tests. Overall, our results show that Goffin cockatoos possess the ability to physically adjust at least the size dimension of manufactured objects relative to a mental template. This ability has previously only been shown in New Caledonian crows, where template matching was suggested as a potential mechanism allowing for the cumulative cultural transmission of tool designs. Our results show that within avian tool users, the ability to recreate a physical template from memory does not seem to be restricted to species that have cumulative tool cultures.

Evidence for widespread changes in the structure, composition, and fire regimes of western North American forests.

Implementation of wildfire- and climate-adaptation strategies in seasonally dry forests of western North America is impeded by numerous constraints and uncertainties. After more than a century of resource and land use change, some question the need for proactive management, particularly given novel social, ecological, and climatic conditions. To address this question, we first provide a framework for assessing changes in landscape conditions and fire regimes. Using this framework, we then evaluate evidence of change in contemporary conditions relative to those maintained by active fire regimes, i.e., those uninterrupted by a century or more of human-induced fire exclusion. The cumulative results of more than a century of research document a persistent and substantial fire deficit and widespread alterations to ecological structures and functions. These changes are not necessarily apparent at all spatial scales or in all dimensions of fire regimes and forest and nonforest conditions. Nonetheless, loss of the once abundant influence of low- and moderate-severity fires suggests that even the least fire-prone ecosystems may be affected by alteration of the surrounding landscape and, consequently, ecosystem functions. Vegetation spatial patterns in fire-excluded forested landscapes no longer reflect the heterogeneity maintained by interacting fires of active fire regimes. Live and dead vegetation (surface and canopy fuels) is generally more abundant and continuous than before European colonization. As a result, current conditions are more vulnerable to the direct and indirect effects of seasonal and episodic increases in drought and fire, especially under a rapidly warming climate. Long-term fire exclusion and contemporaneous social-ecological influences continue to extensively modify seasonally dry forested landscapes. Management that realigns or adapts fire-excluded conditions to seasonal and episodic increases in drought and fire can moderate ecosystem transitions as forests and human communities adapt to changing climatic and disturbance regimes. As adaptation strategies are developed, evaluated, and implemented, objective scientific evaluation of ongoing research and monitoring can aid differentiation of warranted and unwarranted uncertainties.

New Caledonian crows plan for specific future tool use.

The ability to plan for future events is one of the defining features of human intelligence. Whether non-human animals can plan for specific future situations remains contentious: despite a sustained research effort over the last two decades, there is still no consensus on this question. Here, we show that New Caledonian crows can use tools to plan for specific future events. Crows learned a temporal sequence where they were (a) shown a baited apparatus, (b) 5 min later given a choice of five objects and (c) 10 min later given access to the apparatus. At test, these crows were presented with one of two tool-apparatus combinations. For each combination, the crows chose the right tool for the right future task, while ignoring previously useful tools and a low-value food item. This study establishes that planning for specific future tool use can evolve via convergent evolution, given that corvids and humans shared a common ancestor over 300 million years ago, and offers a route to mapping the planning capacities of animals.

The role of intra-operative cell salvage in patient blood management for revision hip arthroplasty: a prospective cohort study.

Cell salvage is an important component of blood management in patients undergoing revision hip arthroplasty surgery. However concerns regarding efficacy and patient selection remain. The aims of this study were to describe intra-operative blood loss, cell salvage re-infusion volumes and red blood cell transfusion rates for revision hip procedures and to identify factors associated with the ability to salvage sufficient blood intra-operatively to permit processing and re-infusion. Data were collected from a prospective cohort of 664 consecutive patients undergoing revision hip surgery at a single tertiary centre from 31 March 2015 to 1 April 2018. Indications for revision surgery were aseptic (n = 393 (59%)) fracture (n = 160 (24%)) and infection (n = 111 (17%)). Salvaged blood was processed and re-infused when blood loss exceeded 500 ml. Mean (SD) intra-operative blood loss was 1038 (778) ml across all procedures. Salvaged blood was re-infused in 505 of 664 (76%) patients. Mean (SD) re-infusion volume was 253 (169) ml. In total, 246 of 664 (37%) patients received an allogeneic red blood cell transfusion within 72 h of surgery. Patients undergoing femoral component revision only (OR (95%CI) 0.41 (0.23-0.73)) or acetabular component revision only (0.53 (0.32-0.87)) were less likely to generate sufficient blood salvage volume for re-infusion compared with revision of both components. Compared with aseptic indications, patients undergoing revision surgery for infection (1.87 (1.04-3.36)) or fracture (4.43 (2.30-8.55)) were more likely to generate sufficient blood salvage volume for re-infusion. Our data suggest that cell salvage is efficacious in this population. Cases where the indication is infection or fracture and where both femoral and acetabular components are to be revised should be prioritised.

Does absolute brain size really predict self-control? Hand-tracking training improves performance on the A-not-B task.

Large-scale, comparative cognition studies are set to revolutionize the way we investigate and understand the evolution of intelligence. However, the conclusions reached by such work have a key limitation: the cognitive tests themselves. If factors other than cognition can systematically affect the performance of a subset of animals on these tests, we risk drawing the wrong conclusions about how intelligence evolves. Here, we examined whether this is the case for the A-not-B task, recently used by MacLean and co-workers to study self-control among 36 different species. Non-primates performed poorly on this task; possibly because they have difficulty tracking the movements of a human demonstrator, and not because they lack self-control. To test this, we assessed the performance of New Caledonian crows on the A-not-B task before and after two types of training. New Caledonian crows trained to track rewards moved by a human demonstrator were more likely to pass the A-not-B test than birds trained on an unrelated choice task involving inhibitory control. Our findings demonstrate that overlooked task demands can affect performance on a cognitive task, and so bring into question MacLean's conclusion that absolute brain size best predicts self-control.

Assessment of the effectiveness of head only and back-of-the-head electrical stunning of chickens.

The study assesses the effectiveness of reversible head-only and back-of-the-head electrical stunning of chickens using 130-950 mA per bird at 50 Hz AC. Three trials were conducted to compare both stunning systems: (a) behavioural assessment of return of consciousness, (b) insensibility to thermal pain, and (c) assessment of return of brain activity with visually evoked potentials (VEPs). Assessment of behaviour suggested that the period of unconsciousness following head-only electrical stunning was shorter in hens compared to broilers. Stunning across the back-of-the-head delayed the time to return of brainstem function compared to stunning with standard head-only electrodes. Additionally, back-of-the-head stunning produced a more prolonged period of electroanalgesia compared to head-only. Based on examination of return of brain function with VEPs in hens, back-of-the-head stunning produced a shorter-lasting stun than standard head-only. However, even for standard head-only, the stun was notably shorter than previously reported. In some birds, brain function had returned within 9 s after the end of stunning. The results suggest that some birds may recover consciousness prior to or during the neck cut. Based on these findings, back-of-the-head stunning and standard head-only stunning of hens should not be recommended without further development.

Anandamide modulates human sperm motility: implications for men with asthenozoospermia and oligoasthenoteratozoospermia.

STUDY QUESTION: What are the levels of anandamide (N-arachidonoylethanolamide, AEA) in human seminal plasma and how are these related to abnormal spermatozoa? SUMMARY ANSWER: Seminal plasma AEA levels were lower in men with asthenozoospermia and oligoasthenoteratozoospermia compared with normozoospermic men. WHAT IS KNOWN ALREADY: AEA, a bioactive lipid, synthesized from membrane phospholipids may signal through cannabinoid receptors (CB1 and CB2) to regulate human sperm functions and male reproduction by modulating sperm motility, capacitation and the acrosome reaction in vitro. Local AEA levels are regulated by the synthetic and degradative enzymes, NAPE-PLD and FAAH, respectively. How the deregulation of this endogenous signalling pathway affects human sperm function(s) is not clear. STUDY DESIGN, SIZE AND DURATION: This was a cross-sectional study of 86 men presenting at an infertility clinic for semen analysis over a period of 2 years. PARTICIPANTS/MATERIALS, SETTING, METHODS: AEA was quantified, by ultra-high performance liquid chromatography-tandem mass spectrometry, in seminal plasma from 86 volunteers. Using qRT-PCR, CB1, CB2, NAPE-PLD and FAAH transcript levels were determined in spermatozoa from men with normozoospermia, asthenozoospermia, oligoasthenoteratozoospermia and teratozoospermia. Normal spermatozoa were exposed in vitro to methanadamide (meth-AEA) to determine its effect on sperm motility, viability and mitochondrial activity. MAIN RESULTS AND THE ROLE OF CHANCE: Seminal plasma AEA levels (mean ± SEM) were significantly lower in men with asthenozoospermia (0.080 ± 0.01 nM; P < 0.05) or oligoasthenoteratozoospermia (0.083 ± 0.01 nM; P < 0.05) compared with normozoospermic men (0.198 ± 0.03 nM). In addition, the levels of spermatozoal CB1 mRNA were significantly decreased in men with asthenozoospermia (P < 0.001) or oligoasthenoteratozoospermia (P < 0.001) compared with normozoospermic controls. Supra-physiological levels of meth-AEA decreased sperm motility and viability, probably through CB1-mediated inhibition of mitochondrial activity. LIMITATIONS, REASONS FOR CAUTION: The inhibitory effect of meth-AEA was only shown in vitro and may not reflect what happens in vivo. WIDER IMPLICATIONS OF THE FINDINGS: As the regulation of the endocannabinoid system appears to be necessary for the preservation of normal sperm function and male fertility, there may be implications for the adverse reproductive consequences of marijuana use. Exocannabinoids, such as Δ(9)-THC, are likely to compete with endocannabinoids at the cannabinoid receptors, upsetting the finely balanced endocannabinoid signalling system. The importance of the endocannabinoid system makes it an attractive target for pharmacological interventions to control male fertility. STUDY FUNDING/COMPETING INTEREST(S): This work was funded in part by miscellaneous educational funds from the University Hospitals of Leicester National Health Services Trust to support the Endocannabinoid Research Laboratory of University of Leicester. The authors declare no competing interests.

Enhanced purinergic contractile responses and P2X1 receptor expression in detrusor muscle during cycles of hypoxia-glucopenia and reoxygenation.

Bladders from patients with detrusor overactivity have an increased atropine-resistant contractile response to nerve stimulation. The bladder has also been shown to be very susceptible to hypoxia-glucopenia and reperfusion injury, leading to the hypothesis that episodes of hypoxia-glucopenia and reoxygenation result in increased atropine-resistant responses to nerve stimulation in the detrusor muscle. Detrusor muscle strips were suspended in a Perspex organ bath chamber of volume 0.2 ml perfused with Krebs solution at 37°C aerated with 21% O2, 5% CO2 and the balance nitrogen. Hypoxia-glucopenia was induced by switching perfusion to Krebs solution without glucose, gassed with 95% nitrogen and 5% CO2. Atropine-resistant contractile responses increased by 40.5 ± 7.3% after four cycles of hypoxia-glucopenia (10 min) and reoxygenation (1 h), whereas α,ß-methylene ATP-resistant responses did not increase. Expression of P2X1 receptors in the bladder was increased after hypoxia-glucopenia and reoxygenation cycling, and ATP release from stimulated bladder strips during cycling was also increased. Other P2X receptor-mediated mechanisms may also be involved in the augmentation of bladder contraction during hypoxia-glucopenia and reoxygenation cycling, because a non-specific P2X antagonist blocked most of the augmented response, whereas a P2X1-specific antagonist prevented only part of the augmentation of contractile response induced by hypoxia-glucopenia and reoxygenation. In conclusion, four cycles of hypoxia-glucopenia and reoxygenation increased the purinergic, but not the cholinergic, contractile responses to nerve stimulation. Increased P2X1 receptor expression and ATP release may have contributed to the augmentation of contractile response induced by hypoxia-glucopenia and reoxygenation. Purinergic antagonists may, therefore, be a useful therapeutic option for the treatment of overactive bladder with increased purinergic-mediated contractions.

Assessing the performance and learning curve of orthopaedic surgical trainees in primary total hip arthroplasty.

INTRODUCTION: The aims of this study were threefold: first, to review the surgical performance of trainees in our departments by reviewing postoperative radiographs and operative times; second, to investigate the effect of supervision and assistant grade on postoperative radiographs and operative times; and third, to monitor trainees over a 6-month period looking for changes in postoperative radiograph appearances and operative times to assess whether these parameters reflect a trainee's learning curve. METHODS: A retrospective evaluation of a continuous series of primary hip arthroplasty procedures performed by 12 trainee orthopaedic surgeons (StR) during their arthroplasty rotation. In total, 348 primary total hip replacement (pTHR) operations were performed by StRs. Operative time, acetabular cup inclination, radiological leg length discrepancy (rLLD), femoral stem alignment (FSA) and the Barrack score for cementation were evaluated. The mean number of pTHRs performed per 6-month placement was 29 (range 15-51). Operative times were available for 292 cases and all postoperative imaging was evaluated. RESULTS: The mean operative time for StRs as first-surgeon was 84.3 minutes (range 42-174 minutes). Significant differences in operative times were observed between individual StRs. As a cohort, the operative times were not affected by the level of supervision but were significantly slower when StRs were assisted by other StRs. Significant differences in rLLD, FSA and Barrack score for cementation were observed across the cohort of StRs, although this did not change at a group or individual level between the first and second halves of the 6-month placement. CONCLUSIONS: Used in isolation, postoperative radiographs and operative time are not an effective measure of the learning curve in primary hip arthroplasty, however, they may be a useful adjunct in assessing the performance of orthopaedic trainees when learning primary hip arthroplasty.

Structure-function relationships among highly diverse T cells that recognize a determinant from influenza virus hemagglutinin.

We have analyzed the structural and genetic basis for T cell recognition of the complex formed between antigen and class II products of the major histocompatibility complex by performing sequence analysis of T cell receptors (TCRs) induced in response to the helper T cell site 1 of the influenza virus hemagglutinin. The results demonstrate, first, that structurally highly diverse TCRs can be utilized in recognition of the same antigen/I-Ed complex: 12 of 13 TCRs utilize unique V alpha/V beta gene segment combinations, suggesting that approximately 70 different V alpha/V beta combinations are available to BALB/c mice in response to this determinant. Second, comparison of these sequences with the ability of each hybridoma to recognize a panel of peptide analogues suggests that alpha and beta chains of these TCRs frequently determine specificity for the NH2-terminal and the COOH terminal portions, respectively, of the site 1 determinant.

The plasma levels of the endocannabinoid, anandamide, increase with the induction of labour.

OBJECTIVE: Plasma anandamide (AEA) levels have previously been shown to be elevated in labour and defective cannabinoid receptor type 1 signalling in mice has been shown to be associated with elevation of corticotrophin-releasing hormone and spontaneous onset of preterm labour. We measured plasma AEA levels in women undergoing induction of labour to define the changes during the transition from the nonlabouring to labouring state. DESIGN: A longitudinal observational study. SETTING: A large UK teaching hospital. POPULATION: Term pregnant women undergoing induction of labour. METHODS: Blood was collected from women before induction of labour and again when they were in active labour. Plasma AEA was extracted and measured using ultraperformance liquid chromatography-tandem mass spectrometry. MAIN OUTCOME MEASURES: The primary outcome variable was change in plasma AEA levels from the nonlabouring to the labouring state. The secondary outcome was induction-to-delivery interval. RESULTS: There was a 1.5-fold increase in mean plasma AEA levels from 1.20 +/- 0.57 nm in the nonlabouring state to 1.82 +/- 0.87 nm in the labouring state (P < 0.0001). Induction-to-delivery interval was predicted by both Bishop's score (P < 0.0001) and percentage change in plasma AEA levels (P < 0.0001). There was a negative correlation between the percentage change in plasma AEA level and the induction-to-delivery interval (r = - 0.28; P = 0.0481). This means that the greater the rise in the plasma AEA levels the shorter the duration of labour. CONCLUSIONS: Plasma AEA levels increase with active labour and the negative correlations between percentage change in plasma AEA levels and induction-to-delivery interval suggest that AEA is likely to be involved in the physiological mechanisms of labour. Whether this increase is essential for myometrial contraction is unclear and needs further investigation.

Bacterial culture of septic synovial structures of horses: does a positive bacterial culture influence prognosis?

REASONS FOR PERFORMING STUDY: The influence of synovial fluid culture on short- and long-term prognosis of cases with septic synovitis requires study. HYPOTHESES: Horses with a positive bacterial culture from septic synovial fluid are less likely to survive or return to successful athletic function than those with a negative bacterial culture from septic synovial fluid. METHODS: Records of mature horses presented to 2 equine referral hospitals for investigation of suspected septic synovitis were examined. Horses (n=206) were included in the study if synovial fluid was submitted for full laboratory examination, including bacterial culture. A diagnosis of septic synovitis was based on a nucleated cell count>30x10(9) cells/l or>90% neutrophils and other clinical, cytological and bacteriological parameters. Long-term follow-up was obtained by telephone questionnaire. Univariate analysis, using the Fisher's exact test, was used for all outcomes. RESULTS: Fourteen (20.9%) of 67 horses with a positive bacterial culture from synovial fluid were subjected to euthanasia because of persistent synovial sepsis compared to 2 (1.44%) of 139 with negative bacterial cultures (P<0.001). Overall survival and successful long-term return to function in horses with a positive bacterial culture was 50% (24/48 horses) compared to 70.5% (74/105) in culture negative horses (P=0.01). In horses that survived to be discharged, successful long-term return to function was not significantly different between culture positive and culture negative groups. Growth of Staphylococcus aureus from synovial fluid did not affect short-term survival to discharge from the hospital compared to other positive bacterial culture; however, successful long-term return to function was only 30.4% (4/13) in horses from which S. aureus was cultured compared to 73.9% (17/23) of horses in which other bacteria were cultured (P=0.015). CONCLUSIONS AND POTENTIAL CLINICAL RELEVANCE: Horses with a positive bacterial culture from a septic synovitis have a poorer prognosis for survival to discharge from hospital and overall long-term return to function than horses that yielded no bacterial growth. When S. aureus was cultured, the long-term prognosis was poorer.

Should practitioners promote physical activity as a treatment for depression?

For many years, experts have been debating the pros and cons of exercise for depression. Proponents of exercise for depression point to those clinical trials which have shown that exercise improves mood, while sceptics point out the methodological problems in many of the apparently positive trials, and the uncertainties around the acceptability of exercise as a treatment for depression. Here two experts critically review the evidence around exercise for depression, provide arguments for and against the promotion of physical activity as a treatment for depression, explore issues around the generalisability of exercise as a treatment for depression and look to the future by discussing ongoing trials that will provide more evidence to inform this important debate.

Physical activity and the prevention, reduction, and treatment of alcohol and other drug use across the lifespan (The PHASE review): A systematic review.

The aim of this review is to systematically describe and quantify the effects of PA interventions on alcohol and other drug use outcomes, and to identify any apparent effect of PA dose and type, possible mechanisms of effect, and any other aspect of intervention delivery (e.g. key behaviour change processes), within a framework to inform the design and evaluation of future interventions. Systematic searches were designed to identify published and grey literature on the role of PA for reducing the risk of progression to alcohol and other drug use (PREVENTION), supporting individuals to reduce alcohol and other drug use for harm reduction (REDUCTION), and promote abstinence and relapse prevention during and after treatment of alcohol and other drug use (TREATMENT). Searches identified 49,518 records, with 49,342 excluded on title and abstract. We screened 176 full text articles from which we included 32 studies in 32 papers with quantitative results of relevance to this review. Meta-analysis of two studies showed a significant effect of PA on prevention of alcohol initiation (risk ratio [RR]: 0.72, 95%CI: 0.61 to 0.85). Meta-analysis of four studies showed no clear evidence for an effect of PA on alcohol consumption (Standardised Mean Difference [SMD]: 0.19, 95%, Confidence Interval -0.57 to 0.18). We were unable to quantitatively examine the effects of PA interventions on other drug use alone, or in combination with alcohol use, for prevention, reduction or treatment. Among the 19 treatment studies with an alcohol and other drug use outcome, there was a trend for promising short-term effect but with limited information about intervention fidelity and exercise dose, there was a moderate to high risk of bias. We identified no studies reporting the cost-effectiveness of interventions. More rigorous and well-designed research is needed. Our novel approach to the review provides a clearer guide to achieve this in future research questions addressed to inform policy and practice for different populations and settings.

Do new caledonian crows solve physical problems through causal reasoning?

The extent to which animals other than humans can reason about physical problems is contentious. The benchmark test for this ability has been the trap-tube task. We presented New Caledonian crows with a series of two-trap versions of this problem. Three out of six crows solved the initial trap-tube. These crows continued to avoid the trap when the arbitrary features that had previously been associated with successful performances were removed. However, they did not avoid the trap when a hole and a functional trap were in the tube. In contrast to a recent primate study, the three crows then solved a causally equivalent but visually distinct problem--the trap-table task. The performance of the three crows across the four transfers made explanations based on chance, associative learning, visual and tactile generalization, and previous dispositions unlikely. Our findings suggest that New Caledonian crows can solve complex physical problems by reasoning both causally and analogically about causal relations. Causal and analogical reasoning may form the basis of the New Caledonian crow's exceptional tool skills.

Prevalence and functional impact of patient-perceived leg length discrepancy after hip replacement.

The aim of this postal survey was to determine the prevalence and impact of patient-perceived leg length discrepancy (LLD) at 5-8 years after primary total hip replacement (THR). A postal audit survey was undertaken of all consecutive patients who had a primary unilateral THR at one elective orthopaedic centre between April 1993 and April 1996. The questionnaire included the Oxford hip score (OHS) and questions about LLD. Questionnaires were received from 1,114 patients. In total, 329 THR patients (30%) reported an LLD, although radiographic analysis revealed that only 36% of these patients had anatomical LLD. Patients with a perceived LLD had a significantly poorer OHS (p < 0.001) and reported more limping than those patients without a perceived LLD. This study found that a third of patients perceived an LLD after THR and that perceived LLD was associated with a significantly poorer midterm functional outcome.

Prediction of preterm labour from a single blood test: The role of the endocannabinoid system in predicting preterm birth in high-risk women.

OBJECTIVE: To determine if plasma concentrations of the N-acylethanolamines (NAEs) N-arachidonoylethanolamine (AEA), N-oleoylethanolamide (OEA) and N-palmitoylethanolamide (PEA) increase in women at high risk for preterm birth (PTB) and whether these could be used to predict preterm delivery and if so, how they compare with current methods. DESIGN: Prospective cohort study. SETTING: A large UK teaching hospital. POPULATION: 217 pregnant women were recruited between 24 and 34 gestational weeks at 'high-risk' for PTB, recruited from a prematurity prevention clinic or antenatal wards. METHODS: Plasma AEA, OEA, and PEA concentrations were measured using ultra-high performance liquid chromatography-tandem mass spectrometry whilst FAAH enzyme activity was measured by fluorometric radiometric assay and CL by ultrasound scan. The clinical usefulness of these measurements were determined by ROC and multivariate analyses. RESULTS: AEA and PEA concentrations were significantly higher in women who delivered prematurely. An AEA concentration >1.095 nM predicted PTB, the gestational age at delivery and the recruitment to delivery interval (RTDI). A PEA concentration >17.50 nM only predicted PTB; FAAH enzyme activity was not related to these changes. Multivariate analysis (all variables) generated an equation to accurately predict the RTDI. CONCLUSIONS: A single plasma AEA or PEA measurement can predict PTB. A single AEA measurement predicts the gestational age of delivery and the remaining period of pregnancy with reasonable accuracy and better than existing conventional tests thus offering a better window for primary prevention of PTB.

Publisher Correction: Mental template matching is a potential cultural transmission mechanism for New Caledonian crow tool manufacturing traditions.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.