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Abstract Background Transcatheter arterial chemoembolization (TACE) combined with targeted therapy and immunotherapy can significantly improve the prognosis of patients with hepatocellular carcinoma (HCC). T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domains (TIGIT) is a novel immunosuppressive molecule. This study aimed to analyze the clinical correlation between TIGIT expression on T cells and patients with HCC. Methods Clinical data from 140 patients with HCC were retrospectively collected, and TIGIT expression on T cells was examined in each patient. Patients were subsequently divided into high- and low-expression groups, and their prognosis was analyzed. Results Patients with a high TIGIT expression on their T cells at baseline had a larger tumor volume, later staging, higher proportion of regulatory T cells, higher blood concentrations of interleukin (IL)-6 and IL-10, and lower interferon-γ concentrations. Following TACE, CD155 concentration decreased; however, TACE did not affect TIGIT expression on T cells. Additionally, among patients receiving TACE combined with apatinib and camrelizumab treatment, patients with a high TIGIT expression on T cells had significantly shorter progression-free survival (PFS) and overall survival times than those of patients in the low-expression group. Patients receiving TACE combined with apatinib and camrelizumab treatment with higher TIGIT expression have shorter PFS time than those receiving TACE combined with apatinib treatment. Conclusions Patients with HCC that have a high TIGIT expression on their T cells exhibited poorer baseline characteristics, immunosuppressive status, and prognosis after receiving TACE combined with apatinib and camrelizumab and maybe more suited to receive TACE combined with apatinib treatment instead.

Abstract Background Fatigue affects nurses negatively and may influence life satisfaction. According to the stress process model, active coping might influence the impact of adverse conditions such as fatigue on well-being measures such as life satisfaction. However, no research examined the associations among nurses’ fatigue, coping styles, and life satisfaction. Methods The cross-sectional study was conducted in Liaoning Province, China. 482 effective questionnaires were collected (effective response rate of 80.3%). The questionnaire included Fatigue Scale-14, Simplified Coping Style Questionnaire and Satisfaction with Life Scale. The association among fatigue, coping styles and fatigue × coping styles interaction with life satisfaction was examined by hierarchical multiple regression analysis. The interaction was visualized by simple slope analysis. Results Mean score of life satisfaction was 22.74 ± 6.11. Active coping moderated the relationship between mental fatigue and life satisfaction. The impacts of mental fatigue on life satisfaction gradually decreased in the low (1 SD below the mean, β=-0.400, P

This research contributes to understanding the spillover effect of customer digital transformation along the supply chain. We take a supply chain relationship perspective to explore the influence of customers’ digital transformation on suppliers’ audit fees and find a significant reduction in such fees when customers undergo digital transformation. An economic mechanism analysis reveals that this transformation reduces audit fees by lowering the risks and costs encountered by auditors. This is achieved by mitigating suppliers’ business risks and improving earnings quality. Heterogeneity analysis reveals that the impact of customers’ digital transformation on suppliers’ audit fees is more pronounced when the supply chain is geographically distant, suppliers with more specific investments and with high levels of market competition.

[Objective] Ecological land fragmentation has a serious impact on the structural integrity and function of the ecosystem. The conflict between construction land expansion and ecological land fragmentation is one of the problems that need to be solved in the process of implementing the development and protection strategy for harmonious coexistence between humans and nature. [Methods] In this study, based on the analysis of temporal and spatial changes in ecological land, a comprehensive indicator system of fragmentation degree was established for the southern Jiangsu Province region to explore the temporal and spatial characteristics of ecological land fragmentation degree. Based on the theory of the environmental Kuznets curve (EKC), the response of ecological land fragmentation degree to construction land expansion was investigated. [Results] (1) From 2000 to 2020, the ecological land in southern Jiangsu Province was mainly converted into construction land, followed by cultivated land. A certain amount of cultivated land and a small amount of construction land were converted into ecological land; (2) The degree of ecological land fragmentation increased first and then decreased. Along the Yangtze River and in the surrounding areas of key water bodies such as the Taihu Lake, the Gucheng Lake, and the Gehu Lake, there was a remarkable increase in the degree of fragmentation; (3) There is an inverted U-shaped relationship between the scale of construction land and the fragmentation of ecological land. With the increase of the area of construction land, the degree of fragmentation of ecological land increases first and then decreases. [Conclusion] The spatiotemporal response of ecological land fragmentation to construction land expansion is consistent with the EKC theory, and most urban centers in southern Jiangsu Province have reached the inflection point by 2020. By exploring the balance between ecological land occupation and compensation, conducting ecological planning in advance, building ecological barriers, timely assessing the impact of construction land expansion on ecological land, and formulating response measures, the layout coordination of construction land and ecological land will be improved, and the coordinated progress of “smart growth” and green development can be realized.

Reasonable signal allocation strategy and effective signal tracking control method are the keys to using aggregate electric vehicles (AEVs) combined with thermal power units to perform the control, improve the quality, and enhance the economy in frequency regulation. Therefore, a frequency regulation control strategy with the participation of AEVs is proposed based on variational mode decomposition (VMD) and double-layer model predictive control (MPC). Firstly, the coordinated optimization control structure of AEVs combined with traditional thermal power units is designed for frequency regulation. The models for thermal power units and load frequency control are established. The AEVs are converted into virtual frequency regulation units, and the load frequency control model of single-area multi-unit with the participation of AEV is constructed. Then, the frequency regulation signal is decomposed into intrinsic mode functions with different frequency components using VMD. The high-frequency components and the low-frequency components are integrated as the frequency regulation signals of AEVs and thermal power units respectively. Optimal redistribution and tracking control of frequency regulation signals within AEVs and thermal power units are realized by double-layer MPC, respectively. Finally, the proposed control strategy is verified by the simulations, and the results show that it can adjust the system frequency effectively and keep a balance between the economy and dynamic performance in frequency regulation.

Natural aggregate is increasingly scarce, and the reuse of solid waste is highly valued. Application of coal gangue aggregate has been drawing broad attention. However, the performance of coal gangue varies greatly in different regions, and physicochemical properties and shape characteristics of coal gangue coarse aggregate significantly affect the performance of concrete. This paper aims at the coal gangue in different mining areas of Shaanxi Province, The crushing index, water absorption, soundness, apparent density and clay content are taken as the macro indexes of coal gangue coarse aggregate, the mineral composition, chemical composition, microstructure and internal pore structure are taken as the microscopic indexes of coal gangue coarse aggregate, and analyses the association between them. In view of the shape difference between coal gangue and nature gravel, the sphericity, angular number(AN) and aggregate particle shape and texture(IAPST) are proposed as shape statistical indexes of coal gangue coarse aggregate, in order to quantify its shape characteristics. Moreover, The influence of macro indexes and shape statistical indexes of coal gangue on workability and strength of concrete are analyzed. The results show that coal gangue with high content of quartz, kaolinite and illite, dense microstructure and small porosity has low water absorption and crushing index. Compared with natural gravel, the coal gangue coarse aggregate has lower sphericity and more irregular shapes. Most coal gangues have high AN and IAPST, showing more sharp edges and rougher surface. Coal gangue with low water absorption and low crushing index is used as coarse aggregate, and the prepared concrete has good workability and high strength, which can meet the C30 strength grade. Shape statistical indexes of coal gangue coarse aggregate affects the strength of concrete when the crushing indexes of coal gangue coarse aggregate is roughly the same. The higher the sphericity, the smaller angular number and texture index, resulting in the lower concrete strength, which is due to the poor interfacial bonding between coal gangue coarse aggregate and cement.

ABSTRACT Objective: A common problem with antithyroid drugs (ATD) treatment in patients with Graves’ disease (GD) is the high recurrence rate after drug withdrawal. Identifying risk factors for recurrence is crucial in clinical practice. We hereby prospectively analyze risk factors for the recurrence of GD in patients treated with ATD in southern China. Subjects and methods: Patients who were newly diagnosed with GD and aged > 18 years were treated with ATD for 18 months and followed up for 1 year after ATD withdrawal. Recurrence of GD during follow-up was assessed. All data were analyzed by Cox regression with P values < 0.05 considered statistically significant. Results: A total of 127 Graves’ hyperthyroidism patients were included. During an average follow-up of 25.7 (standard deviation = 8.7) months, 55 (43%) had a recurrence within 1 year after withdraw of anti-thyroid drugs. After adjustment for potential confounding factors, the significant association remained for the presence of insomnia (hazard ratio (HR) 2.94, 95% confidence interval (CI) 1.47-5.88), greater goiter size (HR 3.34, 95% CI 1.11-10.07), higher thyrotrophin receptor antibody (TRAb) titer (HR 2.66, 95% CI 1.12-6.31) and a higher maintenance dose of methimazole (MMI) (HR 2.14, 95% CI 1.14-4.00). Conclusions: Besides conventional risk factors (i.e., goiter size, TRAb and maintenance MMI dose) for recurrent GD after ATD withdraw, insomnia was associated with a 3-fold risk of recurrence. Further clinical trials investigating the beneficial effect of improving sleep quality on prognosis of GD are warranted.

BeiDou high-precision power line inspection can improve the efficiency and automation level of inspection operations, reduce labor intensity, and save inspection costs. However, although the satellite-based augmentation technology can solve the problem of large-scale positioning, it will introduce too many parameters into the positioning system through the method of parameter estimation. As a result, the behavior of the equation deteriorates, which makes it difficult to separate some parameters, and the convergence time of ambiguity parameters is too long. Under normal circumstances, the satellite-based augmentation standard positioning service needs at least about 30 min to converge to the centimeter level, and the ground-based augmentation system can provide an accurate model. This paper proposes a fast positioning method for satellite-based augmentation assisted by the BeiDou ground-based augmentation station. The receiver adopts the least square method, combined with the extended Kalman filter positioning, to achieve the improvement of the regional positioning effect of the satellite-based augmentation system. Positioning accuracy error does not exceed 1.6 meters. The error in the three directions of X, Y, and Z can be converged to the centimeter level in about 8 min. It can significantly improve the convergence time of satellite-based augmentation, and maintain continuous, stable and high-precision positioning of unmanned aerial vehicle in power line inspection.

PurposeTo search for adaptive response molecules that affect the efficacy of transcatheter arterial chemoembolization (TACE), analyze their clinical correlation with and prognostic value for hepatocellular carcinoma (HCC), and explore their impact on cell biological behavior and their mechanisms of action.MethodsHCC tissue gene sequencing was used to identify differentially expressed genes. The expression of proteoglycan 4 (PRG4) in the serum of 117 patients with HCC who received TACE was detected by enzyme-linked immunosorbent assay. Serum-free medium mimicked TACE-induced nutrient deprivation. Cells with stable knockdown of PRG4 (shPRG4) were constructed to verify the effect and mechanism of PRG4 on the biological behavior of HCC cells in vitro.ResultsThe expression of PRG4 was significantly elevated under TACE-induced starvation conditions. Low PRG4 expression was associated with worse response to TACE treatment, shorter survival time, and stronger HCC migration ability. Furthermore, in vitro experiments showed that knockdown of PRG4 promoted HCC cell migration by enhancing epithelial–mesenchymal transition (EMT) while did not affect proliferation. When PRG4 expression was low, starvation treatment impaired the migratory ability of HCC cells and reduced the chemosensitivity of HCC cells to epirubicin.ConclusionsPRG4 expression predicts survival and TACE treatment response in patients with HCC. Furthermore, knockdown of PRG4 enhanced EMT, leading to HCC cell migration. PRG4 may serve as a biomarker for HCC patients receiving TACE.

The development of both microgrids and electric vehicles has become an important part of the current energy scenario. Useful complementary advantages can be formed between electric vehicles and microgrids, the consumers of which can utilize renewable energy and narrow the peak–valley differences of the net load curve while ensuring their own pecuniary interests. Based on the idea of the Stackelberg game, an optimal dispatch model of a microgrid with electric vehicles is proposed herein, where the benefits of the state of charge are taken into account. In the upper layer of the model, the charging and discharging behaviors of electric vehicles are guided by the goal of minimizing the operating cost of the microgrid. In the lower layer of the model, electric vehicle users adjust the charging and discharging strategies with the goal of maximizing their individual interests. The study results demonstrate that the proposed model not only reflects the benefits of both the master and slave but also reduces the peak–valley differences of the microgrid load. Further, the charging and discharging times of electric vehicles are reduced, and their state of charge is maintained at a high level.

Summary: Background: There were no reports on the associations of aortic arch calcification (AAC) measured by chest X-ray with all-cause mortality and cardiovascular disease (CVD) in older general population. Moreover, previous studies of hemodialysis patients showed that AAC was correlated with left ventricular hypertrophy (LVH) and predicted CVD jointly. Whether the effects remained in the general population is unknown. We examined the associations of AAC with all-cause mortality and CVD in general population and the risk associated with the coexistence of AAC and LVH. Methods: Presence and severity (grades 0-2) of AAC were measured by chest X-ray, and LVH was identified by 12-lead electrocardiogram in 27,166 Chinese aged 50+ years free of CVD from Guangzhou Biobank Cohort Study. Multivariate Cox regressions were used to examine associations of AAC and LVH with outcomes. Findings: During an average follow-up of 14·3 years, 5,350 deaths and 4,012 CVD occurred. Compared to those without AAC at baseline, those with AAC had higher risks of all-cause mortality (HR 1·24, 95% CI 1·17-1·31) and CVD (HR 1·22, 95% CI 1·14-1·30), with dose-response relationship (P ≤ 0·001). Furthermore, those with coexistence of AAC and LVH had higher risks of all-cause mortality (HR 1·72, 95% CI 1·37-2·15) and CVD (HR 1·80, 95% CI 1·40-2·32) than those without AAC and LVH. Interpretation: As chest X-ray has been performed commonly for health screening and in hospital patients when first admitted, AAC measured by chest X-ray can be further applied to assist cardiovascular risk stratification in the community and clinical settings. Funding: The Natural Science Foundation of China (No. 81941019).

Sexual dimorphism is regarded as the consequence of differential responses by males and females to selection pressures. Limb muscle plays a very important role during amplexus, which is likely to be under both natural and sexual selection in anurans. Here, we studied the effects of natural and sexual selection on limb muscle mass in males and females across 64 species of anurans. The results showed that there were non-significant differences in relative limb muscle mass between the sexes among species, exhibiting no sexual dimorphism in limb muscle. Absolute and relative limb muscle mass positively displayed correlations with snout-vent length (SVL)for both sexes. However, neither male-biased operational sex ratio (OSR) nor environmental harshness [e.g., coefficient of variation (CV) in temperature and CV in rainfall] can explain relative limb muscle mass (e.g., forelimb, hindlimb, and total limb muscle) within each sex. The findings suggest that environmental harshness and sexual selection cannot play important roles in promoting variations in limb muscle among anuran species.

Objectives Our study aimed to investigate the relationship between the severity of frailty and the long-term care (LTC) needs of older adults from Chinese communities.Design A cross-sectional study.Setting Three Chinese community health centres. All data were collected by trained researchers through face-to-face collection.Participants We surveyed a total of 540 older residents who aged 60 or older from community in Guangzhou, China.Measures The Chinese version of the Tilburg frailty indicator was used to assess the frailty status of participants. LTC needs was evaluated by Integrated Home Care Services Questionnaire. Using non-adjusted and multivariate adjusted logistic regression analysis to evaluate frailty and LTC needs, then smoothed plots, threshold effect analysis and P for trend were used to further investigate the relationship between them.Results The prevalence of frailty was 45.2% among the 540 older adults enrolled (aged 70.4±8.3 years; 65.7% females). 27% had higher LTC needs, which increased to 65.1% for individuals with frailty. Logistic regression analysis showed that frailty was strongly associated with LTC needs (OR 3.06, 95% CI 2.06 to 4.55, p

Extracts of Cyclocarya paliurus (CP) leaves, a popular sweet tea, inhibit pancreatic β cell apoptosis and have potent hypoglycemic effects, but the identities of the anti-apoptotic bioactive components are still unknown. In the present study, a method using UPLC-Q-TOF/MS based on serum pharmacochemistry combined with target cell extraction was established to rapidly identify direct-acting pancreatic protectants from CP. After orally administering a set amount of CP extract to rats, blood samples were collected to characterize the components that can be absorbed into the blood using UPLC-Q-TOF/MS. Also, target cells (pancreatic β NIT-1 cells) were incubated with CP extract for 24 hours, and cells were collected to identify the components that can bind to the cells using UPLC-Q-TOF/MS. Finally, to evaluate the protective effect of the bioactive components of CP, MTT and TUNEL assays were performed on treated NIT-1 cell induced by streptozotocin (STZ). Three potential direct-acting pancreatic protectants -- kaempferol, quercetin, quadranoside IV -- were identified, and anti-apoptotic effects of kaempferol and quercetin were confirmed in STZ-induced NIT-1 cells. The findings indicate that this combined approach is a feasible, rapid, and expedient tool for capturing potential direct-acting components from natural products such as those from CP leaves.

The potential harm of atmospheric fine particulate matter to human health has been widely concerned around the world. A growing number of studies have shown that PMs exposure can cause damage to respiratory and cardiovascular systems. However, whether PMs can enter the brain and produce neurotoxicity has been an important research topic in the field of neurotoxicity and public health hazards in recent years. In this paper, we review the existing epidemiological evidence and related experimental results to discuss the potential pathways and mechanisms of neurotoxicological effects of PMs on brain. It has been reported that atmospheric PMs can affect the nervous system through the olfactory nerve pathway, blood circulation and other pathways, causing oxidative stress, glial cell activation, neuroinflammation, synaptic plasticity changes and organelle damage and other neurotoxicity. On this basis, it is pointed out that future research in this field should be carried out by multidisciplinary experts in atmospheric chemistry, toxicology and epidemiology.

In this paper, we investigated the technical problem of the recovery of overlength and heavy load conveying booms of self-unloading ships. A method of folding the conveying boom with a hydraulic-four-bar mechanism is presented, and by using a mathematical model for the optimization of folding velocity stationary with ADAMS software, the optimization data and results were obtained. The multi-objective optimization index is introduced, and the multi-objective optimization problem is discussed. The results of the multi-objective optimization showed that parameters such as angular velocity and the change of angular acceleration of the conveyor boom were optimized. The paper has manufactured the connecting rod mechanism, and developed the self-discharging folding conveyance equipment. Through practical application, we determined that the developed folding conveying equipment had the advantages of smooth movement and high folding efficiency.

One of the major clinical manifestations of peripheral neuropathy, either resulting from trauma or diseases, is chronic pain. While it significantly impacts patients’ quality of life, the underlying mechanisms remain elusive, and treatment is not satisfactory. Systemic chronic inflammation (SCI) that we are referring to in this perspective is a state of low-grade, persistent, non-infective inflammation, being found in many physiological and pathological conditions. Distinct from acute inflammation, which is a protective process fighting against intruders, SCI might have harmful effects. It has been associated with many chronic non-communicable diseases. We hypothesize that SCI could be a predisposing and/or precipitating factor in the development of chronic pain, as well as associated comorbidities. We reviewed evidence from human clinical studies indicating the coexistence of SCI with various types of chronic pain. We also collated existing data about the sources of SCI and who could have it, showing that those individuals or patients having SCI usually have higher prevalence of chronic pain and psychological comorbidities. We thus elaborate on the need for further research in the connection between SCI and chronic pain. Several hypotheses have been proposed to explain these complex interactions.

Eye size varies markedly among taxonomic levels, and this variation is often related to the patterns shaped by phylogeny and ecological and behavioral factors. The selective pressures underlying eye size evolution are especially studied in fishes, anurans, birds, and mammals. However, selective pressures underlying the eye size evolution in anurans have inconsistent scaling rules. Here, we investigated the links between eye size and both ecological (e.g., light availability and habitat type) and behavioral factors (e.g., activity time, foraging mobility, defensive strategy, and mating system) among 252 species of anurans by using phylogenetically controlled generalized least-squared (PGLS) regression. Results show that anuran eye size scales hypo-allometrically with body size. However, eye size was not significantly influenced by ecological and behavioral factors, including habitat type, activity time, light availability, foraging mobility, defensive strategy, and mating system. Therefore, neither ecology nor behavior plays a key role in promoting eye size evolution in frogs.

Gene expression data has the characteristics of high dimensionality and a small sample size and contains a large number of redundant genes unrelated to a disease. The direct application of machine learning to classify this type of data will not only incur a great time cost but will also sometimes fail to improved classification performance. To counter this problem, this paper proposes a dimension-reduction algorithm based on weighted kernel principal component analysis (WKPCA), constructs kernel function weights according to kernel matrix eigenvalues, and combines multiple kernel functions to reduce the feature dimensions. To further improve the dimensional reduction efficiency of WKPCA, t-class kernel functions are constructed, and corresponding theoretical proofs are given. Moreover, the cumulative optimal performance rate is constructed to measure the overall performance of WKPCA combined with machine learning algorithms. Naive Bayes, K-nearest neighbour, random forest, iterative random forest and support vector machine approaches are used in classifiers to analyse 6 real gene expression dataset. Compared with the all-variable model, linear principal component dimension reduction and single kernel function dimension reduction, the results show that the classification performance of the 5 machine learning methods mentioned above can be improved effectively by WKPCA dimension reduction.

Species in transformed habitats, frequently labeled as environmental generalists, tend to show broader niches than species in natural habitats. However, how population niche expansion translates into changes in the niches of individual organisms remains unclear, particularly in the context of habitat transformation. Niche expansion could be a product of individuals having broader niches, greater distances among individuals’ niches, or a combination of both processes. This would challenge the traditional conceptions on niche dynamics, which emphasize the role played by individual specialization (IS). Here, using stable isotopes, we computed total niche width (TNW), its within- and between-individual components (WIC and BIC), and IS (the ratio WIC/TNW), in 13 populations of 6 bird species and 8 populations of 3 frog species in natural and transformed habitats. We confirmed that species had broader niche width in transformed than in natural habitats, yet population niche expansion across habitats was mainly a product of increased distance between individuals. Within each habitat type, increases in TNW were linked to increases in WIC for all habitat types, while relationships between TNW and BIC were found in transformed but not in natural habitats. Hence, both increased individual niche width and increased distance among individuals were apparent within habitats, particularly in transformed ones, where increases in WIC dominated. Neither across or within habitats was niche expansion associated with increasing IS. Therefore, our results overturn traditional conceptions associated with the niche variation hypothesis and illustrate that niche expansion is not invariably associated with increased IS, because the distance between individual’s niches (BIC) can increase, as well as the breadth of those niches (WIC).

Nucleonic direct Urca processes and cooling of the massive neutron stars are studied by considering antikaon condensations. Calculations are performed in the relativistic mean field and isothermal interior approximations. Neutrino energy losses of the nucleonic direct Urca processes are reduced when the optical potential of antikaons changes from −80 to −130 MeV. If the center density of the massive neutron stars is a constant, the masses taper off with the optical potential of antikaons, and neutrino luminosities of the nucleonic direct Urca processes decrease for ρCN=0.5 fm−3 but first increase and then decrease for larger ρCN. Large optical potential of antikaons results in warming of the nonsuperfluid massive neutron stars. Massive neutron stars turn warmer with the protonic S01 superfluids. However, the decline of the critical temperatures of the protonic S01 superfluids for the large optical potential of antikaons can speed up the cooling of the massive neutron stars.

PurposeThis study aimed to compare a new Artificial Intelligence (AI) method to conventional mathematical warping in accurately overlaying peripheral retinal vessels from two different imaging devices: confocal scanning laser ophthalmoscope (cSLO) wide-field images and SLO ultra-wide field images.MethodsImages were captured using the Heidelberg Spectralis 55-degree field-of-view and Optos ultra-wide field. The conventional mathematical warping was performed using Random Sample Consensus-Sample and Consensus sets (RANSAC-SC). This was compared to an AI alignment algorithm based on a one-way forward registration procedure consisting of full Convolutional Neural Networks (CNNs) with Outlier Rejection (OR CNN), as well as an iterative 3D camera pose optimization process (OR CNN + Distortion Correction [DC]). Images were provided in a checkerboard pattern, and peripheral vessels were graded in four quadrants based on alignment to the adjacent box.ResultsA total of 660 boxes were analysed from 55 eyes. Dice scores were compared between the three methods (RANSAC-SC/OR CNN/OR CNN + DC): 0.3341/0.4665/4784 for fold 1-2 and 0.3315/0.4494/4596 for fold 2-1 in composite images. The images composed using the OR CNN + DC have a median rating of 4 (out of 5) versus 2 using RANSAC-SC. The odds of getting a higher grading level are 4.8 times higher using our OR CNN + DC than RANSAC-SC (p

Abstract The challenges of seasonal environments are thought to contribute to brain evolution, but in which way is debated. According to the Cognitive Buffer Hypothesis (CBH) brain size should increase with seasonality, as the cognitive benefits of a larger brain should help overcoming periods of food scarcity via, for instance, increased behavioral flexibility. However, in line with the Expensive Brain Framework (EBF) brain size should decrease with seasonality because a smaller brain confers energetic benefits in periods of food scarcity. Empirical evidence is inconclusive and mostly limited to homoeothermic animals. Here we used phylogenetic comparative analyses to test the impact of seasonality on brain evolution across 30 species of anurans (frogs) experiencing a wide range of temperature and precipitation. Our results support the EBF because relative brain size and the size of the optic tectum were negatively correlated with variability in temperature. In contrast, we found no association between the variability in precipitation and the length of the dry season with either brain size or the sizes of other major brain regions. We suggest that seasonality-induced food scarcity resulting from higher variability in temperature constrains brain size evolution in anurans. Less seasonal environments may therefore facilitate the evolution of larger brains in poikilothermic animals.

The brain is among the most energetically costly organs in the vertebrate body. The expensive-tissue hypothesis (ETH) predicts that increasing the size of another costly organ, such as the gut, should compensate for the cost of a small brain. To date, this hypothesis has mainly been tested in homoeothermic animals and in some ectothermic animals (e.g., fishes and anurans). Here, we undertake a test of the ETH by analyzing the relationship between brain size variation and length of the digestive tract in Hylarana guentheri. After controlling for geographical situation and body size, we did not find a correlation between brain mass and the length of the digestive tract in H. guentheri. Our findings suggest that the variation of brain size did not follow general patterns in this species and that the effect of diet quality cannot play a role in the variation of brain.