High Altitude Frogs (Rana kukonoris) Adopt a Diversified Bethedging Strategy in the Face of Environmental Unpredictability

Environmental unpredictability can influence strategies of maternal investment among eggs within a clutch. Models predict that breeding females should adopt a diversified bet-hedging strategy in unpredictable environments, but empirical field evidence from Asia is scarce. Here we tested this hypothesis by exploring spatial patterns in egg size along an altitudinal gradient in a frog species （Rana kukunoris） inhabiting the Tibetan Plateau. Within-clutch variability in egg size increased as the environment became variable （e.g., lower mean monthly temperature and mean monthly rainfall at higher altitudes）, and populations in environments with more unpredictable rainfall produced eggs that were smaller and more variable in size. We provide support for a diversified bet-hedging strategy in high-altitude environments, which experience dynamic weather patterns and therefore are of unpredictable environmental quality. This strategy may be an adaptive response to lower environmental quality and higher unpredictable environmental variance. Such a strategy should increase the likelihood of breeding success and maximize maternal lifetime fitness by producing offspring that are adapted to current environmental conditions. We speculate that in high-altitude environments prone to physical disturbance, breeding females are unable to consistently produce the optimal egg size due to physiological constraints imposed by environmental conditions （e.g., duration of the active season, food availability）. Species and populations whose breeding strategies are adapted to cope with uncertain environmental conditions by adjusting offspring size and therefore quality show a remarkable degree of ability to cope with future climatic changes.

Masting promotes transformation from predation to mutualism in an oak-weevil-rodent system

The significance of ecological non-monotonicity(a function whose first derivative changes signs)in shaping the structure and functions of the ecosystem has recently been recognized,but such studies involving high-order interactions are rare.Here,we have proposed a threetrophic conceptual diagram on interactions among trees,rodents,and insects in mast and non-mast years and tested the hypothesis that oak(Quercus wutaishanica)masting could result in increased mutualism and less predation in an oak-weevil-rodent system in a warm temperate forest of China.Our 14-year dataset revealed that mast years coincided with a relatively low rodent abundance but a high weevil abundance.Masting not only benefited seedling recruitment of oaks through increased dispersal by rodents but also a decrease in predation by rodents and weevils,as well as an increase in the overwintering survival of rodents.Masting appeared to have increased weevil survival by reducing predation of infested acorns by rodents.These results suggest that masting benefits all participants in the plant-insect-rodent system by increasing mutualism and reducing predation behavior(i.e.,a non-monotonic function).Our study highlights the significance of masting in maintaining the diversity and function of the forest ecosystem by facilitating the transformation from predation to mutualism among trophic species.

Influence of morphology and hemodynamics on thrombosis in kawasaki disease patients

Kawasaki Disease(KD)patients with co-occurrent coronary artery aneurysms(CAAs)are prone to thrombosis.This study explores the thrombotic influence of morphology and hemodynamics in KD patients with CAAs.Patient-specific computed tomography angiogram images of 9 patients were used to rebuild coronary models(including 23 aneurysms;10 in thrombosed group,and 13 in non-thrombosed group)and perform computational simulations to obtain the hemodynamic parameters.The thrombosed and non-thrombosed groups were compared in terms of six parameters,namely,the maximum diameter(D_(max)),aspect ratio(R_(l/d)),shape,time-averaged wall shear stress(TAWSS),oscillatory shear index(OSI),and relative residence time(RRT).The results showed that:(1)In thrombosed aneurysms,there were several vortex structures(eddy zone),of which the position changed continuously in a cardiac cycle.In non-thrombosed aneurysms,the streamlines showed a large streaming zone.(2)Abnormal hemodynamic areas of aneurysms with thrombosis tended to appear in the same region(especially the proximal and near myocardial side of aneurysms).(3)In the non-thrombosed group,there was a correlation between the morphological and hemodynamic parameters.In thrombosed aneurysms,the flow pulsatility has a significant impact on the flow pattern.The thrombosed coronary aneurysms exhibited more risk factors and the co-location of hemodynamic abnormalities was consistent with the position of thrombosis.A score of risk factors could provide the thrombotic information of coronary aneurysms,which might be helpful for long-term clinical management of KD patients.

The exploration of flow pattern in the superior vena cava of healthy adults:A 4D flow magnetic resonance imaging study

Our study sought to investigate the blood flow pattern in the superior vena cava(SVC)of healthy adults and to describe the development and characteristics of the flow pattern using 4D flow magnetic resonance imaging(MRI).4D flow MRI data with full coverage of SVC and brachiocephalic veins(BVs)were acquired with a 3-Testa MRI in thirty healthy adults(age:28.70±9.09).Hemodynamic parameters in the SVC,including velocity,velocity vector,flow visualization(pathlines,streamlines),flow waveform and energy loss,were obtained with specialized commercial post-processing software based on 4D flow MRI data.This study found that:(1)The SVC has a pulsating flow waveform with double peaks.(2)Based on BVs flow of the SVC pathline visualization,flow patterns could be divided into three development types:twining(n=14),untwining(n=)and no helical flow(n=7).(3)With the decreasing blood velocity,helical flow areas tended to gradually extend.(4)There were no significant differences in most hemodynamic parameters among the three types.The exploration of the blood flow characteristics of normal SVC may be the first step for capturing pathogenic features before the patients develop symptoms with a certain positive significance.The potential physiological significance of these phenomena deserves more exploration in future studies.

Influence of aortic branch arteries on the hemodynamics of patient-specific type B aortic dissection following TEVAR

Objective:Because of the difficulty in obtaining patient specific flow data,branch arteries are often neglected in the flow simulations of a patient-specific type B aortic dissection(AD)following thoracic endovascular repair(TEVAR).This study aims to investigate the influence of the aortic branch arteries on the hemodynamics and physical flow phenomena commonly associated with aortic modeling of an AD after TEVAR.Methods:The three-dimensional geometry of a type B AD following TEVAR was generated from a high-quality CT dataset.Simulations were performed with all branch arteries,without the four visceral arteries of the abdominal aorta(FVAoAA),and without the upper three branches of the aortic arch(UTBoAA).Results:The removal of the UTBoAA has marginal effect on the flow patterns and hemodynamic parameters in the false lumen(FL);however,regardless of whether there are aorta branches supplied to the FL or not,the omission of FVAoAA will result in a wrong prediction of the flow direction at tears and flow volume to the FL.Conclusions:The omission of aorta branch arteries has great impact on the hemodynamic prediction including flow field and wall shear stress related parameters in a type B AD after TEVAR,which may induce misleading estimates of the potential thrombus in the FL.It is strongly recommended to keep aorta branches in the computational model to predict the post-operative hemodynamic performance in a type B AD following TEVAR.

Thrombotic risk stratification of coronary aneurysms in Kawasaki disease patients:the study of morphology and hemodynamics

To the Editor:Coronary artery aneurysms(CAAs),one of the complications of Kawasaki disease(KD),can cause myocardial ischemia,infarction,and even sudden death.[1]Accurate thrombotic risk stratification in KD patients with CAAs is critical in determining whether patients need aggressive anticoagulation therapy.