Synergistic inhibition of ureolytic activity and growth of Klebsiella pneumoniae in vitro suggests cobinding of fluoride and acetohydroxamic acid at the urease active site and provides a novel strategy to combat ureolytic bacteria.

The ability of ureolytic bacteria to break down stable urea to alkaline ammonia leads to several environmental and health challenges. Ureolytic bacteria such as Helicobacter pylori, Klebsiella pneumoniae, and Proteus mirabilis can become pathogenic and cause persistent infections that can be difficult to treat. Inhibiting urease activity can reduce the growth and pathogenicity of ureolytic bacteria. In the present in vitro study, we investigated the synergistic effects of tannic acid (TA) and the urease inhibitors fluoride (F-) and acetohydroxamic acid (AHA). The concentration of AHA needed for efficient inhibition of the ureolytic activity of K. pneumoniae can be significantly reduced if AHA is coapplied with tannic acid and sodium fluoride (NaF). Thus, only 1.20 µmol l-1 AHA in combination with 0.30 mmol l-1 tannic acid and 0.60 mmol l-1 NaF delayed the onset of ureolytic pH increase by 95.8 % and increased the growth lag phase by 124.3 % relative to untreated K. pneumoniae. At these concentrations, without AHA, TA and NaF increased the onset of the ureolytic pH change by only 37.0 % and the growth lag phase by 52.5 %. The strong inhibition obtained with low concentrations of AHA in triple-compound treatments suggests cobinding of F- and AHA at the urease active site and could reduce the side effects of AHA when it is employed as a drug against e.g. urinary tract infections (UTIs) and blocked catheters. This study reports the basis for a promising novel therapeutic strategy to combat infections caused by ureolytic bacteria and the formation of urinary tract stones and crystalline biofilms on catheters.

Diabetes and Coronary Artery Disease as Risk Factors for Dementia.

AIM: Diabetes is associated with increased risk of dementia, but it is still debated to which degree this risk depends on the presence of atherosclerotic cardiovascular disease. We hypothesized that patients with diabetes and co-existing coronary artery disease (CAD), as a marker of systemic atherosclerotic cardiovascular disease, have substantially higher risk of developing dementia. METHODS: Patients ≥65 years, who underwent coronary angiography were stratified by diabetes and CAD. Outcomes were all-cause dementia, Alzheimer's dementia, and vascular dementia. We estimated adjusted hazard ratios (aHRs) using patients with neither diabetes nor CAD as a reference. RESULTS: A total of 103,859 patients were included. Of these, 23,189 (22%) had neither diabetes nor CAD, 3,876 (4%) had diabetes, 61,020 (59%) had CAD, and 15,774 (15%) had diabetes and CAD. During a median follow-up of 6.3 years, 5,592 (5.5%) patients were diagnosed with all-cause dementia. Patients with diabetes and CAD had the highest hazard rate of all-cause dementia (aHR 1.37, 95% CI 1.24-1.51), including Alzheimer's dementia (aHR 1.41, 95% CI 1.23-1.62) and vascular dementia (aHR 2.03, 95% CI 1.69-2.45). Patients with diabetes alone (aHR 1.14, 95% CI 0.97-1.33) or CAD alone (aHR 1.11, 95% CI 1.03-1.20) had a modestly increased rate of all-cause dementia. CONCLUSION: The combination of diabetes and CAD is associated with increased rate of dementia, in particular vascular dementia, suggesting that the diabetes-related risk of dementia is partly mediated through concomitant atherosclerotic cardiovascular disease. This underscores the importance of atherosclerotic cardiovascular disease prevention in diabetes patients to reduce cognitive decline.

We used national Danish healthcare registries to follow 103,859 patients examined by coronary angiography for up to 10 years to estimate the risk of dementia associated with diabetes and/or coronary artery disease. We found that diabetes and coronary artery disease are, separately, only modest risk factors of dementia. However, diabetes and coronary artery disease in combination were associated with highest risk of dementia, in particular vascular dementia. Out results suggests that the risk of dementia associated with diabetes is partly mediated through the presence atherosclerotic cardiovascular disease, which underscores the importance of atherosclerotic cardiovascular disease prevention in diabetes patients to reduce the risk of cognitive decline.

Epstein-Barr Virus in the Cerebrospinal Fluid and Blood Compartments of Patients With Multiple Sclerosis and Controls.

BACKGROUND AND OBJECTIVES: Epstein-Barr virus (EBV) infection is a major risk factor of multiple sclerosis (MS). We examined the presence of EBV DNA in the CSF and blood of patients with MS and controls. We analyzed whether EBV DNA is more common in the CSF of patients with MS than in controls and estimated the proportions of EBV-positive B cells in the CSF and blood. METHODS: CSF supernatants and cells were collected at diagnostic lumbar punctures from 45 patients with MS and 45 HLA-DR15 matched controls with other conditions, all participants were EBV seropositive. Cellular DNA was amplified by Phi polymerase targeting both host and viral DNA, and representative samples were obtained in 28 cases and 28 controls. Nonamplified DNA from CSF cells (14 cases, 14 controls) and blood B cells (10 cases, 10 controls) were analyzed in a subset of participants. Multiple droplet digital PCR (ddPCR) runs were performed per sample to assess the cumulative EBV positivity rate. To detect viral RNA as a sign of activation, RNA sequencing was performed in blood CD4-positive, CD8-positive, and CD19-positive cells from 21 patients with MS and 3 controls. RESULTS: One of the 45 patients with MS and none of the 45 controls were positive for EBV DNA in CSF supernatants (1 mL). CSF cellular DNA was analyzed in 8 independent ddPCRs: EBV DNA was detected at least once in 18 (64%) of the 28 patients with MS and in 15 (54%) of the 28 controls (p = 0.59, Fisher test). The cumulative EBV positivity increased steadily up to 59% in the successive ddPCRs, suggesting that all individuals would have reached EBV positivity in the CSF cells, if more DNA would have been analyzed. The estimated proportion of EBV-positive B cells was >1/10,000 in both the CSF and blood. We did not detect viral RNA, except from endogenous retroviruses, in the blood lymphocyte subpopulations. DISCUSSION: EBV-DNA is equally detectable in the CSF cells of both patients with MS and controls with ddPCR, and the probabilistic approach indicates that the true positivity rate approaches 100% in EBV-positive individuals. The proportion of EBV-positive B cells seems higher than previously estimated.

Hit-to-Lead Identification and Validation of a Triaromatic Pleuromutilin Antibiotic Candidate.

Herein, we report the hit-to-lead identification of a drug-like pleuromutilin conjugate 16, based on a triaromatic hit reported in 2020. The lead arose as the clear candidate from a hit-optimization campaign in which Gram-positive antibacterial activity, solubility, and P-gp affinity were optimized. Conjugate 16 was extensively evaluated for its in vitro ADMET performance which, apart from solubility, was overall on par with lefamulin. This evaluation included Caco-2 cell permeability, plasma protein binding, hERG inhibition, cytotoxicity, metabolism in microsomes and CYP3A4, resistance induction, and time-kill kinetics. Intravenous pharmacokinetics of 16 proved satisfactory in both mice and pigs; however, oral bioavailability was limited likely due to insufficient solubility. The in vivo efficacy was evaluated in mice, systemically infected with Staphylococcus aureus, where 16 showed rapid reduction in blood bacteriaemia. Through our comprehensive studies, lead 16 has emerged as a highly promising and safe antibiotic candidate for the treatment of Gram-positive bacterial infections.

Impaired cholinergic integrity of the colon and pancreas in dementia with Lewy bodies.

Dementia with Lewy bodies is characterized by a high burden of autonomic dysfunction and Lewy pathology in peripheral organs and components of the sympathetic and parasympathetic nervous system. Parasympathetic terminals may be quantified with 18F-fluoroetoxybenzovesamicol, a PET tracer that binds to the vesicular acetylcholine transporter in cholinergic presynaptic terminals. Parasympathetic imaging may be useful for diagnostics, improving our understanding of autonomic dysfunction and for clarifying the spatiotemporal relationship of neuronal degeneration in prodromal disease. Therefore, we aimed to investigate the cholinergic parasympathetic integrity in peripheral organs and central autonomic regions of subjects with dementia with Lewy bodies and its association with subjective and objective measures of autonomic dysfunction. We hypothesized that organs with known parasympathetic innervation, especially the pancreas and colon, would have impaired cholinergic integrity. To achieve these aims, we conducted a cross-sectional comparison study including 23 newly diagnosed non-diabetic subjects with dementia with Lewy bodies (74 ± 6 years, 83% male) and 21 elderly control subjects (74 ± 6 years, 67% male). We obtained whole-body images to quantify PET uptake in peripheral organs and brain images to quantify PET uptake in regions of the brainstem and hypothalamus. Autonomic dysfunction was assessed with questionnaires and measurements of orthostatic blood pressure. Subjects with dementia with Lewy bodies displayed reduced cholinergic tracer uptake in the pancreas (32% reduction, P = 0.0003) and colon (19% reduction, P = 0.0048), but not in organs with little or no parasympathetic innervation. Tracer uptake in a region of the medulla oblongata overlapping the dorsal motor nucleus of the vagus correlated with autonomic symptoms (rs = -0.54, P = 0.0077) and changes in orthostatic blood pressure (rs = 0.76, P < 0.0001). Tracer uptake in the pedunculopontine region correlated with autonomic symptoms (rs = -0.52, P = 0.0104) and a measure of non-motor symptoms (rs = -0.47, P = 0.0230). In conclusion, our findings provide the first imaging-based evidence of impaired cholinergic integrity of the pancreas and colon in dementia with Lewy bodies. The observed changes may reflect parasympathetic denervation, implying that this process is initiated well before the point of diagnosis. The findings also support that cholinergic denervation in the brainstem contributes to dysautonomia.

GFP fusions of Sec-routed extracellular proteins in Staphylococcus aureus reveal surface-associated coagulase in biofilms.

Staphylococcus aureus is a major human pathogen that utilises many surface-associated and secreted proteins to form biofilms and cause disease. However, our understanding of these processes is limited by challenges of using fluorescent protein reporters in their native environment, because they must be exported and fold correctly to become fluorescent. Here, we demonstrate the feasibility of using the monomeric superfolder GFP (msfGFP) exported from S. aureus. By fusing msfGFP to signal peptides for the Secretory (Sec) and Twin Arginine Translocation (Tat) pathways, the two major secretion pathways in S. aureus, we quantified msfGFP fluorescence in bacterial cultures and cell-free supernatant from the cultures. When fused to a Tat signal peptide, we detected msfGFP fluorescence inside but not outside bacterial cells, indicating a failure to export msfGFP. However, when fused to a Sec signal peptide, msfGFP fluorescence was present outside cells, indicating successful export of the msfGFP in the unfolded state, followed by extracellular folding and maturation to the photoactive state. We applied this strategy to study coagulase (Coa), a secreted protein and a major contributor to the formation of a fibrin network in S. aureus biofilms that protects bacteria from the host immune system and increases attachment to host surfaces. We confirmed that a genomically integrated C-terminal fusion of Coa to msfGFP does not impair the activity of Coa or its localisation within the biofilm matrix. Our findings demonstrate that msfGFP is a good candidate fluorescent reporter to consider when studying proteins secreted by the Sec pathway in S. aureus.

Predator response to the coloured eyespots and defensive posture of Colombian four-eyed frogs.

Deimatic displays, where sudden changes in prey appearance elicit aversive predator reactions, have been suggested to occur in many taxa. These (often only putative) displays frequently involve different components that may also serve antipredator functions via other mechanisms (e.g., mimicry, warning signalling, body inflation). The Colombian four-eyed frog, Pleurodema brachyops, has been suggested to gain protection against predation through putative deimatic displays where they inflate and elevate the posterior part of their body revealing eye-like colour markings. We exposed stationary artificial frogs to wild predators to test whether the two components (eyespot/colour markings, defensive posture) of their putative deimatic display, and their combination, provide protection from predation without the sudden change in appearance. We did not detect any obvious additive effect of defensive posture and eyespots/colour markings on predation risk, but found a marginally significant trend for model frogs in the resting posture to be less attacked when displaying eyespots/colour markings than when they were not, suggesting that the presence of colour markings/eyespots may provide some protection on its own. Additionally, we found that models in a resting posture were overall more frequently attacked on the head than models in a defensive posture, indicating that a defensive posture alone could help redirect predator attacks to non-vital parts of the body. The trends found in our study suggest that the different components of P. brachyops' coloration may serve different functions during a deimatic display, but further research is needed to elucidate the role of each component when accompanied by sudden prey movement.

Collinearity Issues in Autoregressive Models with Time-Varying Serially Dependent Covariates.

First-order autoregressive models are popular to assess the temporal dynamics of a univariate process. Researchers often extend these models to include time-varying covariates, such as contextual factors, to investigate how they moderate processes' dynamics. We demonstrate that doing so has implications for how well one can estimate the autoregressive and covariate effects, as serial dependence in the variables can imply predictor collinearity. This is a noteworthy contribution, since in current practice serial dependence in a time-varying covariate is rarely considered important. We first recapitulate the role of predictor collinearity for estimation precision in an ordinary least squares context, by discussing how it affects estimator variances, covariances and correlations. We then derive a general formula detailing how predictor collinearity in first-order autoregressive models is impacted by serial dependence in the covariate. We provide a simulation study to illustrate the implications of the formula for different types of covariates. The simulation results highlight when the collinearity issue becomes severe enough to hamper interpretation of the effects. We also show that the effect estimates can be biased in small samples (i.e., 50 time points). Implications for study design, the use of time as a predictor, and related model variants are discussed.

Nearly one in five older adults in Danish nursing homes live with type 2 diabetes.

AIM: This study aimed to investigate the prevalence of type 2 diabetes (T2D) among Danish nursing home residents (aged ⩾65 years). METHODS: Individuals with T2D in the Danish population of older adults in 2018 were identified using a Danish diabetes register based on administrative and clinical register data. Data on age, sex, type of housing, educational level and place of origin were obtained from various high-quality administrative registers. We calculated frequencies of T2D among older adults living in nursing homes and in other types of housing. We performed a multiple logistic regression analysis to estimate the odds ratio (OR) of T2D among people living in nursing homes and adjusted for sex, age, educational level and place of origin. RESULTS: All Danish older adults aged ⩾65 years, alive and living in Denmark on 31 December 2018 were included (N=1,170,517). Nursing home residents accounted for 37,891 older adults, and of these, 19% had T2D, whereas 14% of older adults living in other types of housing had T2D. According to the multiple logistic regression analysis, nursing home residents had a higher OR of having T2D compared to older adults living in other types of housing (OR=1.47; confidence interval 1.43-1.51) when adjusting for socio-demographic factors. CONCLUSIONS: The prevalence of T2D in nursing home residents exceeds the prevalence in the background population at ⩾65 years of age. This indicates a need for increased focus on individualised interdisciplinary care plans aimed at maintaining physical function and maximising quality of life for this group of vulnerable older adults.

Risk and Subtypes of Stroke Following New-Onset Postoperative Atrial Fibrillation in Coronary Bypass Surgery: A Population-Based Cohort Study.

Background New-onset postoperative atrial fibrillation (POAF) develops in approximately one-third of patients undergoing cardiac surgery and is associated with a higher incidence of ischemic stroke and increased mortality. However, it remains unknown to what extent ischemic stroke events in patients with POAF are cardioembolic and whether anticoagulant therapy is indicated. We investigated the long-term risk and pathogenesis of postoperative stroke in patients undergoing coronary artery bypass grafting experiencing POAF. Methods and Results This was a register-based cohort study. Data from the WDHR (Western Denmark Heart Registry) were linked with the DNPR (Danish National Patient Register), the Danish National Prescription Register, and the Cause of Death Register. All stroke diagnoses were verified, and ischemic stroke cases were subclassified according to pathogenesis. Furthermore, investigations of all-cause mortality and the use of anticoagulation medicine for the individual patient were performed. A total of 7813 patients without a preoperative history of atrial fibrillation underwent isolated coronary artery bypass grafting between January 1, 2010, and December 31, 2018, in Western Denmark. POAF was registered in 2049 (26.2%) patients, and a postoperative ischemic stroke was registered in 195 (2.5%) of the patients. After adjustment, there was no difference in the risk of ischemic stroke (hazard ratio [HR], 1.08 [95% CI, 0.74-1.56]) or all-cause mortality (HR, 1.09 [95% CI, 0.98-1.23]) between patients who developed POAF and non-POAF patients. Although not statistically significant, patients with POAF had a higher incidence rate (IR; per 1000 patient-years) of cardioembolic stroke (IR, 1 [95% CI, 0.6-1.6] versus IR, 0.5 [95% CI, 0.3-0.8]), whereas non-POAF patients had a higher incidence rate of large-artery occlusion stroke (IR, 1.1 [95% CI, 0.8-1.5] versus IR, 0.7 [95% CI, 0.4-1.4]). Early initiation of anticoagulation medicine was not associated with a lower risk of ischemic stroke. However, patients with POAF were more likely to die of cardiovascular causes than non-POAF patients (P<0.001). Conclusions We found no difference in the adjusted risk of postoperative stroke or all-cause mortality in POAF versus non-POAF patients. Patients with POAF after coronary artery bypass grafting presented with a higher, although not significant, proportion of ischemic strokes of the cardioembolic type.

Size-dependent aggression towards kin in a cannibalistic species.

In juveniles extreme intraspecies aggression can seem counter-intuitive, as it might endanger their developmental goal of surviving until reproductive stage. Ultimately, aggression can be vital for survival, although the factors (e.g., genetic or environmental) leading to the expression and intensity of this behavior vary across taxa. Attacking (and sometimes killing) related individuals may reduce inclusive fitness; as a solution to this problem, some species exhibit kin discrimination and preferentially attack unrelated individuals. Here, we used both experimental and modeling approaches to consider how physical traits (e.g., size in relation to opponent) and genetic relatedness mediate aggression in dyads of cannibalistic Dendrobates tinctorius tadpoles. We paired full-sibling, half-sibling, and non-sibling tadpoles of different sizes together in an arena and recorded their aggression and activity. We found that the interaction between relative size and relatedness predicts aggressive behavior: large individuals in non-sibling dyads are significantly more aggressive than large individuals in sibling dyads. Unexpectedly, although siblings tended to attack less overall, in size-mismatched pairs they attacked faster than in non-sibling treatments. Using a theoretical model to complement these empirical findings, we propose that larval aggression reflects a balance between relatedness and size where individuals trade-off their own fitness with that of their relatives. Lay SummaryBefore you eat someone, you have to attack them first. Here, we investigated the factors that shape aggression in the cannibalistic tadpoles of the dyeing poison frog. We find that aggression depends on both size and relatedness: when set in pairs, large tadpoles are half as aggressive towards their smaller siblings than to nonsibs. It looks like belonging to the same family provides some protection against aggression, though no one is ever truly safe.

Context-dependent coloration of prey and predator decision making in contrasting light environments.

A big question in behavioral ecology is what drives diversity of color signals. One possible explanation is that environmental conditions, such as light environment, may alter visual signaling of prey, which could affect predator decision-making. Here, we tested the context-dependent predator selection on prey coloration. In the first experiment, we tested detectability of artificial visual stimuli to blue tits (Cyanistes caeruleus) by manipulating stimulus luminance and chromatic context of the background. We expected the presence of the chromatic context to facilitate faster target detection. As expected, blue tits found targets on chromatic yellow background faster than on achromatic grey background whereas in the latter, targets were found with smaller contrast differences to the background. In the second experiment, we tested the effect of two light environments on the survival of aposematic, color polymorphic wood tiger moth (Arctia plantaginis). As luminance contrast should be more detectable than chromatic contrast in low light intensities, we expected birds, if they find the moths aversive, to avoid the white morph which is more conspicuous than the yellow morph in low light (and vice versa in bright light). Alternatively, birds may attack first moths that are more detectable. We found birds to attack yellow moths first in low light conditions, whereas white moths were attacked first more frequently in bright light conditions. Our results show that light environments affect predator foraging decisions, which may facilitate context-dependent selection on visual signals and diversity of prey phenotypes in the wild.

Intraoperatively local infiltration anesthesia in hemiarthroplasty patients reduces the needs of opioids: a randomized, double-blind, placebo-controlled trial with 96 patients in a fast-track hip fracture setting.

Background and purpose - Local infiltration analgesia (LIA) is commonly used as a component in multimodal analgesia. Pain management directed towards hip fracture patients operated on with hemiarthroplasty is often based on knowledge regarding pain treatment following elective surgery. In this elderly patient population, it is of value to clarify whether adding local infiltration analgesia (LIA) to the postoperative analgesic regimen might reduce postoperative pain or have an opioid-reducing effect. Patients and methods - 96 hip fracture patients undergoing hemiarthroplasty in spinal anesthesia were included. All patients received a multimodal pain regimen and were randomized to receive either ropivacaine or placebo. All patients received morphine depot-opioid and morphine as rescue medication postoperatively. The primary endpoint was pain during mobilization in the recovery unit on the day of surgery. Secondary endpoints were pain during mobilization the day after surgery and postoperative opioid requirements on the first postoperative day. Results - The levels of pain (NRS) during mobilization both in the recovery unit and on the day after surgery were similar in the 2 groups, with median 4 and 0.5 in the placebo group and median 3.5 and 1 in the ropivacaine group respectively. Total consumption of opioids on day 0 and day 1 were 4.6 mg lower in the ropivacaine group (p = 0.04). Pain during mobilization was registered for only 44 of 96 patients for several reasons, including lack of mobilization. Interpretation - There were similar pain scores in both the local infiltration and placebo group postoperatively. However, substantially reduced opioid consumption was found in patients receiving LIA.

Immune response to a conserved enteroviral epitope of the major capsid VP1 protein is associated with lower risk of cardiovascular disease.

BACKGROUND: Major cardiac events including myocardial infarction (MI) are associated with viral infections. However, how specific infections contribute to the cardiovascular insults has remained largely unclear. METHODS: We employed next generation phage display mimotope-variation analysis (MVA) to explore the link between antibody-based immune response and severe cardiovascular conditions. Here, we used a case-control design, including the first-stage discovery cohort (n = 100), along with cohorts for second-stage discovery (n = 329) and validation (n = 466). FINDINGS: We observed strong antibody response to the peptide antigens with Gly-Ile-X-Asp (G-I-X-D) core structure in healthy individuals but not in patients with MI. Analysis of the origin of this epitope linked it with the N-terminus of the VP1 protein of poliovirus 3 (PV3), but also other species of picornaviruses. Consistently, we found low levels of antibody response to the G-I-X-D epitope in individuals with severe cardiac disease complications. INTERPRETATION: Our findings imply that antibody response to the G-I-X-D epitope is associated with polio vaccinations and that high antibody levels to this epitope could discriminate healthy individuals from prospective MI patients as a blood-derived biomarker. Together, these findings highlight the importance of epitope-specific antibody response and suggest that protective immunity against the polio- and non-polio enteroviral infections support improved cardiovascular health. FUNDING: Estonian Ministry of Education (5.1-4/20/170), Estonian Research Council (PRG573, PRG805), H2020-MSCA-RISE-2016 (EU734791), H2020 PANBioRA (EU760921), European Union through the European Regional Development Fund (Project no. 2014-2020.4.01.15-0012), Helsinki University Hospital grants, Mary and Georg C. Ehrnrooth Foundation, Finnish Eye Foundation, Finska Läkaresällskapet, The Finnish Society of Sciences and Letters, Magnus Ehrnrooth Foundation and Sigrid Jusélius Foundation.

Adherence to the EAT-Lancet Diet and Risk of Stroke and Stroke Subtypes: A Cohort Study.

BACKGROUND AND PURPOSE: We investigated the association between adherence to the EAT-Lancet diet, a sustainable and mostly plant-based diet, and risk of stroke and subtypes of stroke in a Danish population. For comparison, we also investigated the Alternate Healthy Eating Index-2010 (AHEI). METHODS: We used the Danish Diet, Cancer and Health cohort (n=55 016) including adults aged 50 to 64 years at baseline (1993-1997). A food frequency questionnaire was used to assess dietary intake and group participants according to adherence to the diets. Stroke cases were identified using a national registry and subsequently validated by review of medical records (n=2253). Cox proportional hazards models were used to estimate hazard ratios and 95% CIs for associations with the EAT-Lancet diet or the AHEI and risk of stroke and stroke subtypes. RESULTS: Adherence to the EAT-Lancet diet was associated with a lower risk of stroke, although not statistically significant (highest versus lowest adherence: hazard ratio, 0.91 [95% CI, 0.76-1.09]). A lower risk was observed for AHEI (0.75 [95% CI, 0.64-0.87]). For stroke subtypes, we found that adherence to the EAT-Lancet diet was associated with a lower risk of subarachnoid hemorrhage (0.30 [95% CI, 0.12-0.73]), and the AHEI was associated with a lower risk of ischemic stroke (0.76 [95% CI, 0.64-0.90]) and intracerebral hemorrhage (0.58 [95% CI, 0.36-0.93]). CONCLUSIONS: Adherence to the EAT-Lancet diet in midlife was associated with a lower risk of subarachnoid stroke, and the AHEI was associated with a lower risk of total stroke, mainly ischemic stroke and intracerebral hemorrhage.

Pool choice in a vertical landscape: Tadpole-rearing site flexibility in phytotelm-breeding frogs.

Many species of Neotropical frogs have evolved to deposit their tadpoles in small water bodies inside plant structures called phytotelmata. These pools are small enough to exclude large predators but have limited nutrients and high desiccation risk. Here, we explore phytotelm use by three common Neotropical species: Osteocephalus oophagus, an arboreal frog that periodically feeds eggs to its tadpoles; Dendrobates tinctorius, a tadpole-transporting poison frog with cannibalistic tadpoles; and Allobates femoralis, a terrestrial tadpole-transporting poison frog with omnivorous tadpoles. We found that D. tinctorius occupies pools across the chemical and vertical gradient, whereas A. femoralis and O. oophagus appear to have narrower deposition options that are restricted primarily by pool height, water capacity, alkalinity, and salinity. Dendrobates tinctorius tadpoles are particularly flexible and can survive in a wide range of chemical, physical, and biological conditions, whereas O. oophagus seems to prefer small, clear pools and A. femoralis occupies medium-sized pools with abundant leaf litter and low salinity. Together, these results show the possible niche partitioning of phytotelmata among frogs and provide insight into stressors and resilience of phytotelm breeders.

Optimal sampling rates for reliable continuous-time first-order autoregressive and vector autoregressive modeling.

Autoregressive and vector autoregressive models are a driving force in current psychological research. In affect research they are, for instance, frequently used to formalize affective processes and estimate affective dynamics. Discrete-time model variants are most commonly used, but continuous-time formulations are gaining popularity, because they can handle data from longitudinal studies in which the sampling rate varies within the study period, and yield results that can be compared across data sets from studies with different sampling rates. However, whether and how the sampling rate affects the quality with which such continuous-time models can be estimated, has largely been ignored in the literature. In the present article, we show how the sampling rate affects the estimation reliability (i.e., the standard errors of the parameter estimators, with smaller values indicating higher reliability) of continuous-time autoregressive and vector autoregressive models. Moreover, we determine which sampling rates are optimal in the sense that they lead to standard errors of minimal size (subject to the assumption that the models are correct). Our results are based on the theories of optimal design and maximum likelihood estimation. We illustrate them making use of data from the COGITO Study. We formulate recommendations for study planning, and elaborate on strengths and limitations of our approach. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Hard to catch: experimental evidence supports evasive mimicry.

Most research on aposematism has focused on chemically defended prey, but the signalling difficulty of capture remains poorly explored. Similar to classical Batesian and Müllerian mimicry related to distastefulness, such 'evasive aposematism' may also lead to convergence in warning colours, known as evasive mimicry. A prime candidate group for evasive mimicry are Adelpha butterflies, which are agile insects and show remarkable colour pattern convergence. We tested the ability of naive blue tits to learn to avoid and generalize Adelpha wing patterns associated with the difficulty of capture and compared their response to that of birds that learned to associate the same wing patterns with distastefulness. Birds learned to avoid all wing patterns tested and generalized their aversion to other prey to some extent, but learning was faster with evasive prey compared to distasteful prey. Our results on generalization agree with longstanding observations of striking convergence in wing colour patterns among Adelpha species, since, in our experiments, perfect mimics of evasive and distasteful models were always protected during generalization and suffered the lowest attack rate. Moreover, generalization on evasive prey was broader compared to that on distasteful prey. Our results suggest that being hard to catch may deter predators at least as effectively as distastefulness. This study provides empirical evidence for evasive mimicry, a potentially widespread but poorly understood form of morphological convergence driven by predator selection.

Experimental simulation of environmental warming selects against pigmented morphs of land snails.

In terrestrial snails, thermal selection acts on shell coloration. However, the biological relevance of small differences in the intensity of shell pigmentation and the associated thermodynamic, physiological, and evolutionary consequences for snail diversity within the course of environmental warming are still insufficiently understood. To relate temperature-driven internal heating, protein and membrane integrity impairment, escape behavior, place of residence selection, water loss, and mortality, we used experimentally warmed open-top chambers and field observations with a total of >11,000 naturally or experimentally colored individuals of the highly polymorphic species Theba pisana (O.F. MÜller, 1774). We show that solar radiation in their natural Mediterranean habitat in Southern France poses intensifying thermal stress on increasingly pigmented snails that cannot be compensated for by behavioral responses. Individuals of all morphs acted neither jointly nor actively competed in climbing behavior, but acted similarly regardless of neighbor pigmentation intensity. Consequently, dark morphs progressively suffered from high internal temperatures, oxidative stress, and a breakdown of the chaperone system. Concomitant with increasing water loss, mortality increased with more intense pigmentation under simulated global warming conditions. In parallel with an increase in mean ambient temperature of 1.34°C over the past 30 years, the mortality rate of pigmented individuals in the field is, currently, about 50% higher than that of white morphs. A further increase of 1.12°C, as experimentally simulated in our study, would elevate this rate by another 26%. For 34 T. pisana populations from locations that are up to 2.7°C warmer than our experimental site, we show that both the frequency of pigmented morphs and overall pigmentation intensity decrease with an increase in average summer temperatures. We therefore predict a continuing strong decline in the frequency of pigmented morphs and a decrease in overall pigmentation intensity with ongoing global change in areas with strong solar radiation.

Behavioural thresholds of blue tit colour vision and the effect of background chromatic complexity.

Vision is a vital attribute to foraging, navigation, mate selection and social signalling in animals, which often have a very different colour perception in comparison to humans. For understanding how animal colour perception works, vision models provide the smallest colour difference that animals of a given species are assumed to detect. To determine the just-noticeable-difference, or JND, vision models use Weber fractions that set discrimination thresholds of a stimulus compared to its background. However, although vision models are widely used, they rely on assumptions of Weber fractions since the exact fractions are unknown for most species. Here, we test; i) which Weber fractions in long-, middle- and shortwave (i.e. L, M, S) colour channels best describe the blue tit (Cyanistes caeruleus) colour discrimination, ii) how changes in hue of saturated colours and iii) chromatic background noise impair search behaviour in blue tits. We show that the behaviourally verified Weber fractions on achromatic backgrounds were L: 0.05, M: 0.03 and S: 0.03, indicating a high colour sensitivity. In contrast, on saturated chromatic backgrounds, the correct Weber fractions were considerably higher for L: 0.20, M: 0.17 and S: 0.15, indicating a less detailed colour perception. Chromatic complexity of backgrounds affected the longwave channel, while middle- and shortwave channels were mostly unaffected. We caution that using a vision model whereby colour discrimination is determined in achromatic viewing conditions, as they often are, can lead to misleading interpretations of biological interactions in natural - colourful - environments.