Body Size but Not Food Size Determined Head Sexual Dimorphism in Rana kukunoris from the Tibetan Plateau

Sexual dimorphism between males and females is a common pattern observed in the natural world and has become one of the main focuses of evolutionary biology.Amphibian head size and shape are important factors that may influence food acquisition,but knowledge about the sexual differences between amphibian head size and shape is relatively scant.Here,intersexual differences in the head size and shape of Rana kukunoris,which is a high-elevation frog from the Qinghai-Tibet Plateau,were investigated.Significant differences were found in the head shape but not the head size between sexes.A significant correlation was also observed between prey size and head size.However,these correlations disappeared when individual body size was controlled,suggesting that body size but not food size was the main factor resulting in intersexual differences in head size/shape.The results suggested that food competition between sexes did not result in sexual dimorphism of head shape among these frogs.

Multi-objective aerodynamic optimization design of high-speed maglev train nose

Purpose–The nose length is the key design parameter affecting the aerodynamic performance of high-speed maglev train,and the horizontal profile has a significant impact on the aerodynamic lift of the leading and trailing cars Hence,the study analyzes aerodynamic parameters with multi-objective optimization design.Design/methodology/approach–The nose of normal temperature and normal conduction high-speed maglev train is divided into streamlined part and equipment cabin according to its geometric characteristics.Then the modified vehicle modeling function(VMF)parameterization method and surface discretization method are adopted for the parametric design of the nose.For the 12 key design parameters extracted,combined with computational fluid dynamics(CFD),support vector machine(SVR)model and multi-objective particle swarm optimization(MPSO)algorithm,the multi-objective aerodynamic optimization design of highspeed maglev train nose and the sensitivity analysis of design parameters are carried out with aerodynamic drag coefficient of the whole vehicle and the aerodynamic lift coefficient of the trailing car as the optimization objectives and the aerodynamic lift coefficient of the leading car as the constraint.The engineering improvement and wind tunnel test verification of the optimized shape are done.Findings–Results show that the parametric design method can use less design parameters to describe the nose shape of high-speed maglev train.The prediction accuracy of the SVR model with the reduced amount of calculation and improved optimization efficiency meets the design requirements.Originality/value–Compared with the original shape,the aerodynamic drag coefficient of the whole vehicle is reduced by 19.2%,and the aerodynamic lift coefficients of the leading and trailing cars are reduced by 24.8 and 51.3%,respectively,after adopting the optimized shape modified according to engineering design requirements.

EFFECT OF HEAD SHAPE ON THE ADHESION CAPABILITY OF MUSHROOM-LIKE BIOLOGICAL ADHESIVE STRUCTURES

Theoretical studies have been extensively performed to reveal the mechanism of the biological adhesive structure with a flat head.However,most biological adhesive structures have a big head.Here we investigate the effect of the head shape on the adhesion capability of a mushroomlike adhesion structure based on a finite element model.We show that a mushroom-like head produces significant adhesion enhancement.We investigate also the effect of the elastic modulus of the adhesive structure on the adhesion.Our results are consistent with existing experimental results.

Effect of Nose Shape on Semi-Armor-Piercing Warhead Penetration Performance

The numerical simulations of different head shape semi-armor-piercing warheads penetrating thin steel target are done using the finite element software ANSYS/LS-DYNA, and the whole process of different nose shape semi-armor-piercing warheads vertically penetrating the thin steel plate is compared. Besides, the influence of impact angle on penetration performance of three different nose shape projectiles is researched. The analysis results indicate that the nose shape has a significant influence on semi-armor-piercing warhead penetration performance.The effect of impact angle on the three kinds of projectiles' residual kinetic energy and deflection is different. The research results provide references for designing of warhead and battlefield damage assessment.

Computed Tomography Assessment of Cephalic Index and Sella Turcica Dimensions and Morphology in a Nigerian Population

Cephalic index(CI)is the percentage of biparietal diameter to the occipitofrontal diameter of the skull and can be used in forensic investigations in cases of disputed identity where only fragments of the head/skull are available.The sella turcica houses the pituitary gland whose hormones regulate the functions of many other glands and systems of the body.Abnormal sizes of sella turcica could indicate sella/pituitary pathology with health implications.This study aimed to assess CI,head shapes and sella turcica dimensions and morphology of the Yoruba tribe of Nigeria.The objectives are:to relate CI and head shapes with sella turcica dimensions and morphology,to use CI and head shape to identify and distinguish the Yoruba tribe from other tribes,to use CI and head shape to distinguish between genders.Skull/head and sella turcica dimensions were measured on 321 retrospectively enlisted normal cranial Computed Tomography(CT)images of Yoruba subjects,mean age 55(SD±17)years,in a Tertiary Hospital in South-West Nigeria between January 2020 and April 2021,and then CI calculated.Data was analyzed using IBM SPSS 27(IBM Corp.Armonk,NY,USA,2019).Predominant head shape of the studied group was dolichocephalic.Mean CI was 70.0±3.7 and showed no statistically significant difference between gender(P=0.097).Mean sella length,depth;and anteroposterior diameter was 1.22±0.24 cm,0.80±0.15 cm,1.34±0.25 cm respectively.Mean sella length and depth showed significant difference between gender(P=0.0001;P=0.032)respectively.Head shape has no association with sella dimensions and morphology.Head shape and CI may stratify populations in forensic practice and surgical planning.

Occipital pressure sores in two neonates

The preference for a specific head shape can be influenced by people's culture,religious beliefs and race.Modern Chinese people prefer a"talented"head shape,which is rounded and has a long profile.To obtain their preferred head shape,some parents try to change their neonates'sleeping position.Due to these forced sleeping positions,positional skull deformities,such as plagiocephaly,may be present during the first few months of life.In this article,we report two neonatal cases,of Hui nationality and Dongxiang nationality,with occipital pressure sores that were caused by using hard objects as pillows with the intention of obtaining a flattened occiput.The pressure sores were deep to the occipital bone and needed surgical management.These pressure sores caused wounds that were repaired by local skin flaps,after debridement,and the use of external constraints from a dense sponge-made head frame for approximately two weeks.One case recovered with primary healing after surgical operation.The other case suffered from a disruption of the sutured wound,and a secondary operation was performed to cover the wound.These occipital pressure sores are avoidable by providing guidance to the parents in ethnic minorities'area regarding the prevention,diagnosis and management of positional skull deformity.