Nocturnal sentry duty and cardiometabolic characteristics in armed forces personnel

BACKGROUND Sleep deprivation can lead to increased body weight and blood pressure(BP),but the latent effects of partial sleep deprivation related to required night sentry duties within a short-term period on cardiometabolic characteristic changes in military personnel are unclear.AIM To investigate the association between night sentry duty frequency in the past 3 months and cardiometabolic characteristics in armed forces personnel.METHODS A total of 867 armed forces personnel who were aged 18-39 years and did not take any antihypertensive medications in Taiwan in 2020 were included.The frequency of night sentry duty was self-reported via a questionnaire(average number of night sentry shifts per month for the past 3 months).Hemodynamic status was assessed via the resting BP and pulse rate(PR).Cardiometabolic risk factors were defined according to the International Diabetes Federation criteria.Multivariable linear regression analyses of the associations between night sentry duties and PR,BP,and other metabolic syndrome(MetS)marker levels were performed,with adjustments for age,sex,substance use,body mass index and aerobic fitness.Multiple logistic regression analysis was carried out to determine the associations between night sentry duties and the prevalence of each MetS feature.

Analysis of Electrical Dipoles Interaction Forces as a Function of the Distance and of the Form of Electrical Force Law

Here, we initially introduced and demonstrated two principles: orientation OR principle and attraction AT principle of electrical dipoles. The OR principle stipulates that any two electrical dipoles P1A, P1B, from two bodies A and B, at any distance in the free state each, will be reciprocally oriented parallel and in the same sense if the electrical interaction forces F between them are of decreasing type with distance r. If the electrical interaction forces F are of increasing type with distance, the two dipoles will be reciprocally oriented parallel but on the opposite sense. The AT principle stipulate that any two electrical dipoles P1A, P1B, at any distance in the free state each, will present always a reciprocal force of attraction FD in both cases of orientation accordingly to OR principle in case of any type of electrical force F decreasing or increasing with distance. These findings may complete our previous work where we found that FD force, between two electrical dipoles P1A, P1B considered at atomic and nuclear level, is in fact the actual gravitation Newton force FN. The paper must be considered together with this work for more consistency.

Strength characteristics of modified polypropylene fiber and cement-reinforced loess

The reinforcement and stabilization of loess soil are duscussed by using fibers as the reinforcement and cement as the stabilization materials.To study the strength characteristics of loess soil reinforced by modified polypropylene(MPP) fiber and cement,samples were prepared with six different fiber contents,three different cement contents,three different curing periods and three kinds of fiber length.The samples were tested under submergence and non-submergence conditions for the unconfined compressive strength(UCS),the splitting tensile strength and the compressive resilient modulus.The results indicated that combined reinforcement by PP fiber and cement could significantly improve the early strength of loess to 3.65–5.99 MPa in three days.With an increase in cement content,the specimens exhibited brittle fracture.However,the addition of fibers gradually modified the mode of fracture from brittle to ductile to plastic.The optimal dosage of fiber to reinforce loess was in the range of 0.3%–0.45% and the optimum fiber length was 12 mm,for which the unconfined compressive strength and tensile strength reached their maxima.Based on the analysis of failure properties,cement-reinforced loess specimens were susceptible to brittle damage under pressure,and the effect of modified polypropylene fiber as the connecting "bridge" could help the specimens achieve a satisfactory level of ductility when under pressure.

Task assignment in ground-to-air confrontation based on multiagent deep reinforcement learning

The scale of ground-to-air confrontation task assignments is large and needs to deal with many concurrent task assignments and random events.Aiming at the problems where existing task assignment methods are applied to ground-to-air confrontation,there is low efficiency in dealing with complex tasks,and there are interactive conflicts in multiagent systems.This study proposes a multiagent architecture based on a one-general agent with multiple narrow agents(OGMN)to reduce task assignment conflicts.Considering the slow speed of traditional dynamic task assignment algorithms,this paper proposes the proximal policy optimization for task assignment of general and narrow agents(PPOTAGNA)algorithm.The algorithm based on the idea of the optimal assignment strategy algorithm and combined with the training framework of deep reinforcement learning(DRL)adds a multihead attention mechanism and a stage reward mechanism to the bilateral band clipping PPO algorithm to solve the problem of low training efficiency.Finally,simulation experiments are carried out in the digital battlefield.The multiagent architecture based on OGMN combined with the PPO-TAGNA algorithm can obtain higher rewards faster and has a higher win ratio.By analyzing agent behavior,the efficiency,superiority and rationality of resource utilization of this method are verified.

A single-task and multi-decision evolutionary game model based on multi-agent reinforcement learning

In the evolutionary game of the same task for groups,the changes in game rules,personal interests,the crowd size,and external supervision cause uncertain effects on individual decision-making and game results.In the Markov decision framework,a single-task multi-decision evolutionary game model based on multi-agent reinforcement learning is proposed to explore the evolutionary rules in the process of a game.The model can improve the result of a evolutionary game and facilitate the completion of the task.First,based on the multi-agent theory,to solve the existing problems in the original model,a negative feedback tax penalty mechanism is proposed to guide the strategy selection of individuals in the group.In addition,in order to evaluate the evolutionary game results of the group in the model,a calculation method of the group intelligence level is defined.Secondly,the Q-learning algorithm is used to improve the guiding effect of the negative feedback tax penalty mechanism.In the model,the selection strategy of the Q-learning algorithm is improved and a bounded rationality evolutionary game strategy is proposed based on the rule of evolutionary games and the consideration of the bounded rationality of individuals.Finally,simulation results show that the proposed model can effectively guide individuals to choose cooperation strategies which are beneficial to task completion and stability under different negative feedback factor values and different group sizes,so as to improve the group intelligence level.

The effects of 12 weeks of functional strength training on muscle strength,volume and activity upon exposure to elevated Gz forces in high-performance aircraft personnel

Background:Technological advancements in modern military and acrobatic jet planes have resulted in extraordinary psychophysiological loads being exerted upon flying personnel,including inducing neck and back pain.The purpose of this study was to examine the effects of 12 weeks of functional strength training on 1)the volume and strength of the neck and shoulder muscles and 2)muscular activity upon exposure to helmets of different masses and elevated Gz forces in a long-arm centrifuge in high-performance aircraft personnel.Methods:Eighteen participants underwent 12 weeks of functional strength training(n=12)or the control protocol(n=6)without additional strength training.Pre-and post-intervention tests included evaluations of isometric strength of the head extensor muscles,flexion,and lateral flexion and rotation,as well as magnetic resonance imaging(MRI)to measure the volume of the m.sternocleidomastoideus,m.trapezius,and deep neck muscles.Furthermore,during a long-arm centrifuge(+1.4 and+3Gz)protocol,the muscular activity levels of the m.sternocleidomastoideus,m.trapezius and m.erector spinae muscles were assessed without a flight helmet,with a helmet,and with a helmet and night vision goggles.Each participant’s perception of muscular strain was noted immediately after the long-arm centrifuge protocol.Results:The maximal isometric strength in all exercises and muscle volumes increased in the training group but not the control group(P<0.05).Relative muscle activity(%MVC)with a helmet decreased after the intervention in the training but not the control group(P=0.01).Relative muscle activity while wearing a helmet and night vision goggles was higher after intervention in the control group than in the training group(P<0.01).The perceived muscular strain of the neck muscles induced by the long-arm centrifuge did not differ between the groups.Conclusions:Twelve weeks of functional strength training improves the maximal isometric strength and volume of neck and shoulder muscles and leads to lower relative muscle activation upon exposure to elevated Gz forces in a long-arm centrifuge.

Choice of discount rate in reinforcement learning with long-delay rewards

In the world, most of the successes are results of longterm efforts. The reward of success is extremely high, but before that, a long-term investment process is required. People who are “myopic” only value short-term rewards and are unwilling to make early-stage investments, so they hardly get the ultimate success and the corresponding high rewards. Similarly, for a reinforcement learning(RL) model with long-delay rewards, the discount rate determines the strength of agent’s “farsightedness”.In order to enable the trained agent to make a chain of correct choices and succeed finally, the feasible region of the discount rate is obtained through mathematical derivation in this paper firstly. It satisfies the “farsightedness” requirement of agent. Afterwards, in order to avoid the complicated problem of solving implicit equations in the process of choosing feasible solutions,a simple method is explored and verified by theoreti cal demonstration and mathematical experiments. Then, a series of RL experiments are designed and implemented to verify the validity of theory. Finally, the model is extended from the finite process to the infinite process. The validity of the extended model is verified by theories and experiments. The whole research not only reveals the significance of the discount rate, but also provides a theoretical basis as well as a practical method for the choice of discount rate in future researches.

Side force control on slender body by self-excited oscillation flag

Strong asymmetrical vortices appear on the leeward of slender body at high angles of attack, which has very unfavorable effect on the stability and control of the aircraft. A method is developed to control the side force of slender body at high angles of attack, and is verified in wind tunnel. A thin-film triangular self-excited oscillation flag is fixed at the tip of the slender body model whose semi-apex angle is 10°. Side force is approximately linearly proportional to roll-setting angle of self-excited oscillation flag at high angles of attack, and the slop of fitting straight line obtained by the least square method is -0.158. The linear relationship between side force and roU-setting angle provides convenience for developing side force control law of slender body at high angles of attack. Experimental data shows that the side force coefficients vary linearly with roll-setting angles when a specific plastic self-excited oscillation flag is used as the control flag. The range of side force coefficient and roll-setting angle are, respectively, -3.2 to 3.0 and -20° to 20°. The device is simple, effective, and is of great potential in engineering application.

Rationale and design of the cardiorespiratory fitness and hospitalization events in armed forces study in Eastern Taiwan

AIM To investigate the association between cardiorespiratory fitness and hospitalization events in a cohort of large voluntary arm forces in Taiwan. METHODS The cardiorespiratory fitness and hospitalization events in armed forces(CHIEF) is a retrospective cohort consisting of more than 4000 professional military members aged 18-50 years in Eastern Taiwan. All participants received history taking, physical examination, chest radiography, 12-lead electrocardiography, blood tests for cell counts and fasting glucose, lipid profiles, uric acid, renal function and liver function in the Hualien Armed Forces General Hospital during 2014. In addition, participants were required to undergo two indoor resistant exercise tests including 2-min push-up and 2-min sit-up, both scored by infrared sensing, and one outdoor endurance 3000-m none weight-bearing running test, the main indicator of cardiorespiratory fitness in the Military Physical Training and Testing Center in Eastern Taiwan in 2014. RESULTS Hospitalization events for cardiovascular disease, acute kidney injury, rhabdomyolysis, severe infectious disease, acute psychiatric illness, diabetes, orthopedic surgery and mortality will be identified in the National Insurance Research Database for 10 years. CONCLUSION CHIEF will be among the largest Eastern Asian armed forces cohort, in which physical status was strictly evaluated to follow up the hospitalization events for severe illness.

Defence force activities in marine protected areas:environmental management of Shoalwater Bay Training Area,Queensland,Australia

Environmental management of military activities is of growing global concern by defence forces. As one of the largest landholders in Australia, the Australian Defence Force （ADF） is increasingly concerned with sustainable environmental management. This paper focuses on how the ADF is maintaining effective environmental management, especially in environmentally sensitive marine protected areas. It uses Shoalwater Bay Training Area （SWBTA） as a research example to examine environmental management strategies conducted by the ADF. SWBTA is one of the most significant Defence training areas in Australia, with a large number of single, joint and combined military exercises conducted in the area. With its maritime component contained in the Great Barrier Reef Marine Park （GBRMP）, the Great Barrier Reef World Heritage Area （GBRWHA）, and abutting Queensland＇s State Marine Parks, it has high protection values. It is therefore vital for the ADF to adopt environmentally responsible management while they are conducting military activities. As to various tools employed to manage environmental performance, the ISO 14001 Environmental Management System （EMS） is widely used by the ADE This paper exanlines military activities and marine environmental management within SWBTA, using the Talisman Saber （TS） exercise series as an example. These are extensive joint exercises conducted by the ADF and the United States defence forces. The paper outlines relevant legislative framework and environmental policies, analyses how the EMS operates in environmental management of military activities, and how military activities comply with these regulations. It discusses the implementation of the ADF EMS, including risk reduction measures, environmental awareness training, consultation and communication with stakeholders. A number of environmental management actions used in the TS exercises are presented to demonstrate the EMS application. Our investigations to this point indicate that the ADF is complying with all relevant legislation and policies. Further research is required to confirm compliance and conclude that military activities have good accord with environmental management objectives.

An Analysis of the Origin of the Interaction Force between Electric Charges, including Justification of the ln<i>r</i>Term in the Completed Coulomb’s Law, in HM16 Ether

In this study, we demonstrate the correctness of our 2010 hypothesis regarding the need to complete Coulomb’s FC law with the term lnr, resulting in the completed FCC force. For this purpose, we consider the electrical interactions between charged microparticles (MPs), which develop as fundamental vibrations (FVs) in ether, producing the vibrational strains &epsilon;and &gamma;and the resulting stresses &sigma;and &tau;, as percussions of ether cells (ECs) upon the MP surface. The stresses &sigma;?and?&tau;produce a resultant force FP, due to the percussions which constitute the real electric force FCC. The spatial effect of ether on FP is demonstrated by an analytical method, considering the electrical interaction between MPs through various equidistant spatial paths li of FVs, modelled on the basis of the Huygens principle for waves. For this issue, we utilized a numerical calculation, which could be generalized. But this spatial effect of the ether leads at a very slow decreasing of the FP forces ratio rF when doubling the distance l, in contrast to Coulomb’s FC forces whose ratio rF?decreases accentuate with doubling l. Accordingly, the necessity of including the term ln r in the FCC force, which is limited to 1.0 for doubling l, at long distances, was justified.

In situ observation of surface structures of cardiovascular endothelial cells with atomic force microscope

Objective To observe the surface structures of cardiovascular endothelial cells in situ with atomic force microscope （AFM）. Methods Fresh aorta and aortic valve were dissected from 10 healthy male New Zealand white rabbits. Before fixed in 1% formaldehyde, the fresh tissues were washed in the buffer phosphate solution. Under general microscope, the fixed aorta or valve was spread on the double side stick tape which had already been stuck on the glass slide. The intima of aorta or the aorta side of valve was towards upside, Then the specimen was dried under 37 degrees centigrade in an attemperator and was washed with pure water. After dried again, the specimen was loaded on the platform ofNanoScope Ⅲa AFM and was scanned in tapping mode with the scanning speed of 0.5 HZ. Results The surface structures of endothelial cell on the fixed and dried tissue could be observed clearly in situ with AFM. aortic endothelial cells were large, branched and arranged sparsely and parallel to the direction of blood flow, whereas endothelial cells on aorta valve surface were small, less branched and arranged intensively and vertical to the direction of blood flow. When the scanning range was dwindled, granular ultra-structures could be observed on the surface of endothelial cells, and, as the scanning range was dwindled further, fissure and convolution could be seen on the surface of granules from aortic endothelial cells. Centre cavity and surrounding swelling volcano-like structure could be seen on the surface of granules from endothelial cells of aortic valve. Conclusions It＇s feasible to observe the surface ultra-structures of cardiovascular endothelial cells in situ with AFM and morphological information provided by AFM might be of clinical value in future histopathological diagnosis（JGeriatr Cardiol2009; 6：178-181）.

Disqualifying Medical Conditions of Flying Personnel in Chinese Army and Air Force

After inpatient aircrews of Chinese Army and Air Force are treated at local hospitals, their health status will be evaluated. If it is aeronautically adaptable, the conclusion would be flying qualification; if it may impact the flight safety or the flight environment may aggravate

Improving the corrosion resistance of AZ91D magnesium alloy through reinforcement with titanium carbides and borides

A composite consisting of magnesium matrix reinforced with a network of TiC-Ti_(2)AlC-TiB_(2)particulates has been fabricated using a practical in-situ reactive infiltration technique.The microstructural and phase composition of the magnesium matrix composite(R-Mg)was investigated using SEM/EDS and XRD.The analyses revealed the complete formation of TiC,Ti_(2)AlC and TiB_(2)particles in the magnesium matrix.Comparative compression tests of R-Mg and AZ91D alloy showed that the reinforcing particles improve the mechanical properties of Mg alloy.EIS and potentiodynamic polarization results indicated that the reinforcing particles significantly improve the corrosion resistance of the reinforced alloy in 3.5%NaCl solution.

Driving force coordinated control of an 8x8 in-wheel motor drive vehicle with tire-road friction coefficient identification

Because of the complexities of tire-road interaction,the wheels of a multi-wheel distributed electricdrive vehicle can easily slip under certain working conditions.As wheel slip affects the dynamic per-formance and stability of the vehicle,it is crucial to control it and coordinate the driving force.With this aim,this paper presents a driving force coordination control strategy with road identification for eight-wheeled electric vehicles equipped with an in-wheel motor for each wheel.In the proposed control strategy,the road identification module estimates tire-road forces using an unscented Kalman filter al-gorithm and recognizes the road adhesion coefficient by employing the recursive least-square method According to road identification,the optimal sip ratio under the current driving condition is obtainedand a controller based on sliding mode control with a conditional integrator uses this value for accel-eration slip regulation.The anti-slip controller obtains the adjusting torque,which is integrated with the driver-command-based feedforward control torque to implement driving force coordination control.The results of hardware-in-loop simulation show that this control strategy can accurately estimate tire-roadrces as well as the friction coefficient,and thus,can effectively fulfill the purpose of driving force coordinated control under different driving conditions.

Properties and strengthening mechanism of brush plated nanoparticle reinforced composite coatings

Nanoparticle reinforced nickel matrix composite coatings, such as n-Al2O3/Ni, n-SiO2/Ni, n-SiC/Ni and n-TiO2/Ni, were fabricated by brush plating technique. Hardness, wear resistance and contact-fatigue resistance of the composite coatings were determined, and strengthening mechanism of the composite coatings was discussed. Results show that the composite coatings have superior properties to the Ni metal coating. Compared with properties of brush plated Ni metal coating, the composite coatings have hardness over 1.5 times and wear resistance capability of about 2.5 times. The strengthening mechanism of the composite coatings mainly includes fine-crystal grain effect, nanoparticle dispersion effect and dislocation effect.

Must pilots permanently quit flying career after treatment for colorectal cancer?-Medical waiver for Air Force pilots with colorectal cancer: Three case reports

BACKGROUND Colorectal cancer(CRC)could seriously threaten the physical and mental health of pilots.Shall they end their flying after treatment of CRC?With this study,we investigated the possibility of a gradual medical waiver for such pilots to fly aircrafts again after treatment of CRC.CASE SUMMARY We analyzed the medical waiver and clinical data of 3 pilots with CRC,who had accepted the treatment at the Department of General Surgery,Air Force Medical Center(formerly,Air Force General Hospital)between 2013 and 2018.All 3 cases underwent a series of comprehensive treatment courses,including radical resection of CRC,sequential radiotherapy,and chemotherapy.The follow-up results were satisfactory.After passing through the high-risk period of recurrence and metastasis of CRC,they all were given a medical waiver for flying again.Medical observation showed that their flying operations were safe.CONCLUSION The CRC treatment shall follow the guidelines for diagnosis and treatment and should simultaneously protect the combating capabilities of pilots as much as possible.It is safe for pilots with CRC,who are continuously monitored under medical observation after passing through the high-risk period of recurrence and metastasis,to undertake military flight missions again.

Psychological stress and long-term blood pressure variability of military young males:The cardiorespiratory fitness and hospitalization events in armed forces study

BACKGROUND Acute stress might increase short-term heart rate variability and blood pressure variability(BPV);however,chronic stress would not alter short-term BPV in animal models.AIM To examine the association of psychological stress with long-term BPV in young male humans.METHODS We prospectively examined the association of chronic psychological stress with long-term BPV in 1112 healthy military males,averaged 32.2 years from the cardiorespiratory fitness and hospitalization events in armed forces study in Taiwan.Psychological stress was quantitatively evaluated with the Brief Symptom Rating Scale(BSRS-5),from the least symptom of 0 to the most severe of 20,and the five components of anxiety,insomnia,depression,interpersonal sensitivity,and hostility(the severity score in each component from 0 to 4).Longterm BPV was assessed by standard deviation(SD)for systolic and diastolic blood pressure(SBP and DBP),and average real variability(ARV),defined as the average absolute difference between successive measurements of SBP or DBP,across four visits in the study period from 2012 to 2018(2012-14,2014-15,2015-16,and 2016-18).RESULTS The results of multivariable linear regressions showed that there were no correlations of the BSRS-5 score with SDSBP,SDDBP,ARVSBP,and ARVDBP after adjusting for all the covariates[β(SE):-0.022(0.024),-0.023(0.026),-0.001(0.018),and 0.001(0.020),respectively;P>0.05 for all].In addition,there were also no correlations between each component of the BSRS score and the long-term BPV indexes.CONCLUSION Our findings suggest that chronic psychological stress might not be associated with long-term BPV in military young male humans.

A review of novel ternary nano-layered MAX phases reinforced AZ91D magnesium composite

In recent decades, the demand for lightweight and high specific strength materials brings about the development of magnesium matrix composites. Different from some traditional binary ceramic particles, such as SiC, Al_(2)O_(3), the novel ternary nano-layered M_(n+1)AX_(n)(MAX)phase carbide or nitride ceramics exhibit metal-like properties and self-lubricate capacity(where “M” is an early transition metal, “A” belongs to the group A element, “X” is C or/and N, and n = 1–3). Ti_(2)AlC, as the representative of the MAX phase, was interestingly introduced into the magnesium matrix. Layered Ti_(2)AlC MAX phased reinforced AZ91D magnesium composites manufactured through the stir casting exhibit sufficient deformation capacity due to unique deformation behaviors of MAX, namely delamination and the formation of kinking band. Further,the Ti_(2)AlC-AZ91D composites exhibit a distinctive characteristic in strengthening mechanism, damping mechanism and tribological capacity due to the other special properties of MAX phase, such as self-lubricated property. Accordingly, to give a comprehensive understanding, we overviewed the fabrication process, microstructural characterization, mechanical properties, damping property and tribological capacity on these composites. In order to understand the A-site effect in MAX phase on the microstructure, we introduced another representative Ti_(3)SiC_(2)MAX phase to explain the interfacial evolution. In addition, due to the high aspect ratio of MAX, MAX particles could be orientationally regulated in Mg matrix by plastic deformation such as hot extrusion. Herein, we discussed the anisotropic mechanical and physical properties of the textured composites produced by hot extrusion. Moreover, the potential applications and future development trends of MAX phases reinforced magnesium matrix composites were also given and prospected.