scholarly journals The crouching of the shrew: Mechanical consequences of limb posture in small mammals

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2131 ◽  
Author(s):  
Daniel K. Riskin ◽  
Corinne J. Kendall ◽  
John W. Hermanson
Keyword(s):  
Small Mammals ◽  
The Body ◽  
Mechanical Power ◽  
Total Power ◽  
Blarina Brevicauda ◽  
Important Trend ◽  
Limb Posture ◽  
Evolution Of Mammals ◽  
The Cost ◽  
Kinetics Of

An important trend in the early evolution of mammals was the shift from a sprawling stance, whereby the legs are held in a more abducted position, to a parasagittal one, in which the legs extend more downward. After that transition, many mammals shifted from a crouching stance to a more upright one. It is hypothesized that one consequence of these transitions was a decrease in the total mechanical power required for locomotion, because side-to-side accelerations of the body have become smaller, and thus less costly with changes in limb orientation. To test this hypothesis we compared the kinetics of locomotion in two mammals of body size close to those of early mammals (< 40 g), both with parasagittally oriented limbs: a crouching shrew (Blarina brevicauda; 5 animals, 17 trials) and a more upright vole (Microtus pennsylvanicus; 4 animals, 22 trials). As predicted, voles used less mechanical power per unit body mass to perform steady locomotion than shrews did (P= 0.03). However, while lateral forces were indeed smaller in voles (15.6 ± 2.0% body weight) than in shrews (26.4 ± 10.9%;P= 0.046), the power used to move the body from side-to-side was negligible, making up less than 5% of total power in both shrews and voles. The most power consumed for both species was that used to accelerate the body in the direction of travel, and this was much larger for shrews than for voles (P= 0.01). We conclude that side-to-side accelerations are negligible for small mammals–whether crouching or more upright–compared to their sprawling ancestors, and that a more upright posture further decreases the cost of locomotion compared to crouching by helping to maintain the body’s momentum in the direction of travel.

scholarly journals The changes in power requirements and muscle efficiency during elevated force production in the fruit fly Drosophila melanogaster.

1997 ◽  
Vol 200 (7) ◽  
pp. 1133-1143 ◽  
Author(s):  
F O Lehmann ◽  
M H Dickinson
Keyword(s):  
Drosophila Melanogaster ◽  
Power Output ◽  
Force Production ◽  
Fruit Fly ◽  
Reynolds Numbers ◽  
Power Input ◽  
Mechanical Power ◽  
Total Power ◽  
Mechanical Power Output ◽  
The Cost

The limits of flight performance have been estimated in tethered Drosophila melanogaster by modulating power requirements in a 'virtual reality' flight arena. At peak capacity, the flight muscles can sustain a mechanical power output of nearly 80 W kg-1 muscle mass at 24 degrees C, which is sufficient to generate forces of approximately 150% of the animal's weight. The increase in flight force above that required to support body weight is accompanied by a rise in wing velocity, brought about by an increase in stroke amplitude and a decrease in stroke frequency. Inertial costs, although greater than either profile or induced power, would be minimal with even modest amounts of elastic storage, and total mechanical power energy should be equivalent to aerodynamic power alone. Because of the large profile drag expected at low Reynolds numbers, the profile power was approximately twice the induced power at all levels of force generation. Thus, it is the cost of overcoming drag, and not the production of lift, that is the primary requirement for flight in Drosophila melanogaster. By comparing the estimated mechanical power output with respirometrically measured total power input, we determined that muscle efficiency rises with increasing force production to a maximum of 10%. This change in efficiency may reflect either increased crossbridge activation or a favorable strain regime during the production of peak forces.

Influence of the cost of technological equipment of body production on indicators of efficiency of working processes

2021 ◽  
pp. 28-32
Author(s):  
Keyword(s):  
Quality Index ◽  
Production Efficiency ◽  
Statistical Data ◽  
The Body ◽  
Technological Equipment ◽  
Production Body ◽  
Body Production ◽  
The Cost ◽  
Efficiency Indicators ◽  
Selection Of

The possibilities for the development of bodywork in the context of the growing level of competition are analyzed in the article. The technological processes of bodywork are considered and the problem of choosing technological equipment is indicated. The statistical data about the efficiency indicators of company body divisions, operating in the body repair market in Krasnoyarsk, are presented. A composite quality index for the equipment of the bodywork department (using the example of body stocks) is proposed and calculated, and on its basis, some recommendations are given for companies which plan to enter the market of body repair services. Keywords: body production, body repair, body equipment, body production efficiency, selection of technological equipment

THE USE OF HEART RATE TELEMETRY FOR DYNAMIC CONTROL OF THE FUNCTIONAL STATE DURING COMPUTER TESTING AND BIOFEEDBACK IN KNOWLEDGE WORKERS

2021 ◽  
Author(s):  
M.M. Nekrasova ◽  
◽  
I.V. Fedotova ◽  
S.A. Polevaya ◽  
Keyword(s):  
Heart Rate ◽  
Functional State ◽  
Work Experience ◽  
Knowledge Workers ◽  
Management Strategies ◽  
Dynamic Control ◽  
The Body ◽  
Biofeedback Training ◽  
Total Power ◽  
Neurohumoral Regulation

Abstract: Introduction. Increasing information loads can lead to the development of professional stress and work-related illnesses in knowledge workers. The development and implementation of modern methods of control and correction of the functional state of employees in the conditions of activity is relevant. The study aims – to explore the dynamics of the functional state of knowledge workers in the conditions of modeling the cognitive load on the computer and during the training on neurofeedback (NFB) based on the parameters of the electroencephalogram (EEG). Materials and methods. 17 researchers (4 men and 13 women aged 22-63 years (34.8±3.4), with an average work experience of 12.1±3.3 years) participated in the study on the basis of voluntary informed consent. Results. A significant increase in the index of the alpha rhythm was shown by 29.4% of the subjects. It was found that the total power of the spectrum of heart rate variability (HRV) is higher, the adaptive risk is lower in the group that successfully passed alpha training (p<0.05). According to the results of continuous personalized heart rate telemetry, the dynamics of the functional state (FS) during the examination was determined for each subject. Conclusion. A significant influence of the state of neurohumoral regulation systems and adaptive reserves of the body on the success of the biofeedback training was established, which is the basis for the development of methodological approaches to the correction of FS, taking into account individual optimal management strategies.

Brain size evolution in small mammals: test of the expensive tissue hypothesis

Mammalia ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ying Jiang ◽  
Jia Yu Wang ◽  
Xiao Fu Huang ◽  
Chun Lan Mai ◽  
Wen Bo Liao
Keyword(s):  
Small Mammals ◽  
Brain Size ◽  
Reproductive Investment ◽  
Generalized Least Squares ◽  
Offspring Number ◽  
Size Evolution ◽  
Large Brain ◽  
Species Evolution ◽  
The Cost ◽  
Expensive Tissue Hypothesis

Abstract Brain size exhibits significant changes within and between species. Evolution of large brains can be explained by the need to improve cognitive ability for processing more information in changing environments. However, brains are among the most energetically expensive organs. Enlarged brains can impose energetic demands that limit brain size evolution. The expensive tissue hypothesis (ETH) states that a decrease in the size of another expensive tissue, such as the gut, should compensate for the cost of a large brain. We studied the interplay between energetic limitations and brain size evolution in small mammals using phylogenetically generalized least squares (PGLS) regression analysis. Brain mass was not correlated with the length of the digestive tract in 37 species of small mammals after correcting for phylogenetic relationships and body size effects. We further found that the evolution of a large brain was not accompanied by a decrease in male reproductive investments into testes mass and in female reproductive investment into offspring number. The evolution of brain size in small mammals is inconsistent with the prediction of the ETH.

Improving the efficiency of metal-bonded diamond abrasive end tools by improving manufacturing technology

2021 ◽  
Vol 23 (2) ◽  
pp. 66-80
Author(s):  
Valentin Smirnov ◽  
◽  
Dmitry Lobanov ◽  
Vadim Skeeba ◽  
Ivan Golyushov ◽  
...  
Keyword(s):  
High Speed ◽  
High Speed Steel ◽  
Carbon Steels ◽  
Manufacturing Technology ◽  
The Body ◽  
Processing Technologies ◽  
Medium Carbon ◽  
The Cost ◽  
Diamond Abrasive ◽  
Bearing Part

Introduction. Difficult-to-machine materials with enhanced physical and mechanical properties are increasingly being used in various industries. Such materials are used in mechanical engineering for the manufacture of parts and assemblies of machines and mechanisms, in the production and processing of food products where increased operational requirements are required. In modern production, along with traditional methods of intensifying technological operations, combined and hybrid processing technologies are used. For the finishing of products, abrasive grinding with a diamond tool is used. One of the problems hindering the wide practical application of this method in industry is the fact that it has a high prime cost caused by the cost of materials used in the manufacture and the laboriousness of the tool shaping process. This leads to the need to develop a new technology for manufacturing diamond tools. The purpose of the work is to increase the efficiency of the end diamond abrasive tool with a metal bond by using carbon steels as a body material, increasing the strength of the connection between the body and the diamond-bearing part, as well as choosing an effective tool manufacturing technology. Research methodology. To gain this task, a technology for manufacturing end diamond abrasive tools is developed and tested. Allowing using the technology of capacitor welding to connect the diamond-bearing part with the shank and use medium-carbon hardened high-quality steels with a hardness of 45-60 HRC as the shank material. The strength of the connection of the body with the working diamond-bearing part of the grinding head samples is determined by tensile testing on a 1958U10 tensile machine with maximum load 100 kN. The quality of the joint is assessed visually by the presence of discontinuities in the joint, as well as by examining the microstructure and measuring the microhardness of the weld and heat-affected zones. The microhardness of the welded joint is measured using an HMV-G21ST semi-automatic microhardness tester (Shimadzu, Japan) at a load of 50 g. Results and discussion. Thus, the results of comparative studies allow us to assert that the strength of the connection between the shank and the working diamond-bearing part according to the proposed technology surpasses similar characteristics of the strength of the connection between the shank and the diamond-bearing layer of grinding heads obtained by the method selected by the prototype. Conclusions. The proposed technology for the manufacture of diamond heads increases the strength of the connection between the body and the diamond-bearing working part, reduces the cost of manufacturing the grinding heads due to the use of hardened medium-carbon steels as the material of the tool body instead of high-speed steel grades, the technology is simplified and the possibility of automating the manufacture of tools appears.

STATE OF AUTONOMIC REGULATION OF HEART RHYTHM IN YOUNG AND AGED RATS BEFORE AND AFTER APPLICATION OF DIFFERENT REGIMENS OF RHYTHMIC EXTREME COOLING

2020 ◽  
pp. 436-443
Author(s):  
В. В. Кулик ◽  
В. Г. Бабийчук
Keyword(s):  
Heart Rate ◽  
Metabolic Regulation ◽  
Experimental Studies ◽  
Autonomic Regulation ◽  
The Body ◽  
Total Power ◽  
Aged Rats ◽  
Cooling Mode ◽  
Adaptive Capabilities ◽  
Extreme Cold

В работе изучено влияние разных режимов ритмических экстремальных холодовых воздействий на состояние вегетативной регуляции сердечного ритма у молодых и старых крыс. По данным спектрального анализа вариабельности сердечного ритма установлено, что у молодых крыс использование температурных режимов ритмических экстремальных холодовых воздействий, РЭХВ (-120 °С; -120 °С; -120 °С) и (-60 °С; -120 °С; -120 °С) значительно повышало адаптационные возможности организма за счет активации собственных гомеостатических регуляторных систем. При этом комбинированный режим РЭХВ (-60 °С; -120 °С; -120 °С) оказался наиболее оптимальным для старых животных, поскольку его применение не сопровождалось чрезмерной активацией симпатико-адреналовой системы на ранних этапах экспериментальных исследований в отличие от режима (-120 °С; -120 °С; -120 °С). Кроме того, использование данного режима охлаждения способствовало статистически значимому увеличению показателей общей мощности спектра нейрогуморальной регуляции не столько за счет повышения активности гуморально-метаболического звена регуляции, преобладание которого характерно для пожилого возраста, сколько благодаря увеличению тонуса вегетативных центров, причем парасимпатические влияния на миокард превалировали над симпатическими. The influence of various rhythmic extreme cold effects on the state of autonomic regulation of heart rate in young and aged rats was studied. According to the spectral analysis of heart rate variability, it has been found that in young rats, using rhythmic extreme cold exposures (RECE) temperature regimens of (-120 °С; -120 °С; -120 °С) and (-60 °С; -120 °С; -120 °С) significantly increased adaptive capabilities of the body due to the activation of its own homeostatic regulatory systems. At the same time, the combined regimen of RECE (-60 °С; -120 °С; -120 °С) occurred to be the most optimal for aged animals, since its use was not accompanied with an excessive activation of sympathoadrenal system at the early stages of experimental studies, in contrast to the regimen (-120 °С; -120 °С; -120 °С). In addition, the use of this cooling mode contributed to a statistically significant increase in the total power of spectrum of neurohumoral regulation not so much due to a rise in activity of humoral-metabolic regulation link, the prevalence of which is characteristic of an old age, but due to an increase in the tone of vegetative centers, herewith the parasympathetic effects on the myocardium prevailed sympathetic ones.

scholarly journals Unstable Hemostasis and Specific Postoperative Complications (Literature Review)

2020 ◽  
Vol 5 (4) ◽  
pp. 98-102
Author(s):  
D. V. Lebedeva ◽  
E. A. Ilyicheva
Keyword(s):  
Postoperative Complications ◽  
Rapid Development ◽  
Point Of View ◽  
The Body ◽  
Cost Of Treatment ◽  
Duration Of Hospital Stay ◽  
Technical Errors ◽  
Perioperative Bleeding ◽  
The Cost

Perioperative bleeding occupies a leading place among all surgical complications and, despite the rapid development of surgery, remains relevant to this day. In addition to an increase in mortality, bleeding can cause the development of other postoperative complications, which lead to disability of patients and to a decrease in the quality of life in all age groups. Most perioperative bleeding are caused by technical errors. This article reviews the problem of perioperative bleeding from the point of view of impaired coagulation capabilities of the body. The main etiopathogenetic features of hemostasis during the development of this complication are considered. The analysis of postoperative complications, which were directly or indirectly caused by bleeding during or after surgery, is presented. The prevalence of these complications in various areas of surgery has been demonstrated. More detailed study of the hemostasis system and the identification of predictors of hemostasis difficulties before the surgery may cause an improvement in the results of surgical treatment and reduce the number of postoperative complications and the duration of hospital stay. Accordingly, this will lead to a decrease in the cost of treatment and an increase in patient satisfaction with the medical care. In connection with the above, there is a great interest among surgeons and anesthesiologists in preventing the development of perioperative bleeding.

scholarly journals The Peculiarities of Civil-Legal Regulation of Transplantation in Ukraine and Europe

2018 ◽  
Vol 8 (1) ◽  
pp. 33-48
Author(s):  
Alla Herts
Keyword(s):  
Treatment Process ◽  
Developed Countries ◽  
Legal Regulation ◽  
Modern Medicine ◽  
The Body ◽  
Accessibility Of Health Services ◽  
Surgical Field ◽  
Processed Form ◽  
The Cost ◽  
Cadaveric Transplantation

Abstract In modern realities the issue of the quality and accessibility of health services, the cost of medicines, examinations and treatment in general is being increasingly frequently discussed. The attention is focused on such a narrow surgical field as transplantation, because in Ukraine thousands of patients are waiting in line for organ transplantation and very few operations are performed. The main, most secure and common type of transplantation is the transplantation of organs and tissues from a deceased person, the dead body. Cadaveric transplantation, which is used in most developed countries, is hardly carried out in Ukraine. This is due to the fact that the current regulatory base of Ukraine in the field of transplantation does not fully meet the needs of modern medicine and has many gaps. The aim of donation is a future transplantation (including and in cases of blood transfusion and reproductive cells use). The parts (tissues, organs, their parts, individual cells) extracted (separated) from the body in the process of donation can be used generally in the treatment process in a processed form (blood plasma) or in the original state (fertilized reproductive cells). The detailed analysis of the provisions of the national legal system makes it possible to conclude that, despite the absence of direct regulation of relations concerning organ donation and transplantation as material relations, the legal regulations provide the fundamental provisions, which determine their material nature, and therefore offer opportunities for agreementbased regulation. In our opinion, one of the essential legal means of ensuring the rights of participants in the relations of donation and transplantation can be their agreement-based regulation. The peculiarities of civil-legal regulation of transplantation in Ukraine and Europe are simultaneously analysed; and the grounds of its legitimacy are defined.

scholarly journals A MODIFIED GENETIC ALGORITHM FOR FINDING FUZZY SHORTEST PATHS IN UNCERTAIN NETWORKS

2016 ◽  
Vol XLI-B2 ◽  
pp. 299-304 ◽  
Author(s):  
A. A. Heidari ◽  
M. R. Delavar
Keyword(s):  
Genetic Algorithm ◽  
Shortest Path ◽  
Shortest Paths ◽  
The Body ◽  
Shortest Path Problems ◽  
Conventional Procedure ◽  
Path Lengths ◽  
The Cost ◽  
Uncertain Networks ◽  
Exploration Exploitation

In realistic network analysis, there are several uncertainties in the measurements and computation of the arcs and vertices. These uncertainties should also be considered in realizing the shortest path problem (SPP) due to the inherent fuzziness in the body of expert's knowledge. In this paper, we investigated the SPP under uncertainty to evaluate our modified genetic strategy. We improved the performance of genetic algorithm (GA) to investigate a class of shortest path problems on networks with vague arc weights. The solutions of the uncertain SPP with considering fuzzy path lengths are examined and compared in detail. As a robust metaheuristic, GA algorithm is modified and evaluated to tackle the fuzzy SPP (FSPP) with uncertain arcs. For this purpose, first, a dynamic operation is implemented to enrich the exploration/exploitation patterns of the conventional procedure and mitigate the premature convergence of GA technique. Then, the modified GA (MGA) strategy is used to resolve the FSPP. The attained results of the proposed strategy are compared to those of GA with regard to the cost, quality of paths and CPU times. Numerical instances are provided to demonstrate the success of the proposed MGA-FSPP strategy in comparison with GA. The simulations affirm that not only the proposed technique can outperform GA, but also the qualities of the paths are effectively improved. The results clarify that the competence of the proposed GA is preferred in view of quality quantities. The results also demonstrate that the proposed method can efficiently be utilized to handle FSPP in uncertain networks.

scholarly journals The burden of the current curative expenditure of injury in Dalian, China-A study based on “System of Health Accounts 2011”

2020 ◽  
Author(s):  
Shu Sun ◽  
Liuna Yang ◽  
Xinzhu Hu ◽  
Yalan Zhu ◽  
Boxi Liu ◽  
...  
Keyword(s):  
Foreign Body ◽  
Lower Limb ◽  
Control Strategies ◽  
Age Groups ◽  
The Body ◽  
Age Group ◽  
Curative Care ◽  
Health Accounts ◽  
System Of Health Accounts ◽  
The Cost

Abstract Background Injury is one of the major public health problems, which causes more than 5 million deaths in the world every year. Cases of specific types of injury put a tremendous threat to human health and also add a heavy medical burden on individuals and societies. This study was to calculate and analyze the current curative expenditure (CCE) of injury in Dalian and consequently to provide control strategies for decision-makers. Main text: A total of 565 medical institutions were selected with multistage stratified cluster random sampling, containing 4,375,351 valid samples. Subsequently, the distribution of injury CCE in different dimensions (including age and site of injury) was analyzed under the framework of System of Health Accounts 2011(SHA 2011) using the established database. There were increases from 32.36/100,000 in 2006 to 37.34/100,000 in 2017 and from 46.12/100,000 in 2006 to 54.48/100,000 in 2017 in urban and rural residents respectively. The study found that the CCE of injury in Dalian had reached 1572.73 million RMB, accounting for 7.45% of the total curative care expenditure. In the 15–25 age group, the cost of injury accounts for a larger proportion of CCE than other age groups. Among the injuries in different regions of the body, injuries to the spine, lower limb, head and foreign body entering cost the most. Conclusions Dalian has a relatively serious burden of injury costs. The essential and primary goal is to reduce the cost and increase the benefit of attending to patients with injuries. Specific control strategies should be tilted toward the age group 15–25. Injuries to the spine, lower limb, head and foreign body entering also should be priorities of interventions.

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