scholarly journals “Simple” Biomechanical Model for Ants Reveals How Correlated Evolution among Body Segments Minimizes Variation in Center of Mass as Heads Get Larger

2020 ◽  
Vol 60 (5) ◽  
pp. 1193-1207 ◽  
Author(s):  
Philip S L Anderson ◽  
Michael D Rivera ◽  
Andrew V Suarez
Keyword(s):  
Center Of Mass ◽  
Relative Size ◽  
Biomechanical Model ◽  
The Body ◽  
Model Complexity ◽  
Stabilizing Selection ◽  
Form And Function ◽  
Wide Range ◽  
Simple Models

Synopsis The field of comparative biomechanics strives to understand the diversity of the biological world through the lens of physics. To accomplish this, researchers apply a variety of modeling approaches to explore the evolution of form and function ranging from basic lever models to intricate computer simulations. While advances in technology have allowed for increasing model complexity, insight can still be gained through the use of low-parameter “simple” models. All models, regardless of complexity, are simplifications of reality and must make assumptions; “simple” models just make more assumptions than complex ones. However, “simple” models have several advantages. They allow individual parameters to be isolated and tested systematically, can be made applicable to a wide range of organisms and make good starting points for comparative studies, allowing for complexity to be added as needed. To illustrate these ideas, we perform a case study on body form and center of mass stability in ants. Ants show a wide diversity of body forms, particularly in terms of the relative size of the head, petiole(s), and gaster (the latter two make-up the segments of the abdomen not fused to thorax in hymenopterans). We use a “simple” model to explore whether balance issues pertaining to the center of mass influence patterns of segment expansion across major ant clades. Results from phylogenetic comparative methods imply that the location of the center of mass in an ant’s body is under stabilizing selection, constraining the center of mass to the middle segment (thorax) over the legs. This is potentially maintained by correlated rates of evolution between the head and gaster on either end. While these patterns arise from a model that makes several assumptions/simplifications relating to shape and materials, they still offer intriguing insights into the body plan of ants across ∼68% of their diversity. The results from our case study illustrate how “simple,” low-parameter models both highlight fundamental biomechanical trends and aid in crystalizing specific questions and hypotheses for more complex models to address.

scholarly journals A case-study in cross-disciplinary student work: a CNC-manufactured body for FSAE racing

2011 ◽  
Author(s):  
Emmanouil Vermisso ◽  
Keyword(s):  
Mechanical Engineering ◽  
Time Span ◽  
The Body ◽  
Collaborative Effort ◽  
Student Work ◽  
Race Car ◽  
Wide Range ◽  
Academic Year

The project discussed here involves the contribution of architecture students towards the design and fabrication of the body for an open wheel race-car for the annual SAE competition (Society of Automotive Engineers). The development of this body constitutes only a portion of a wider project that involves engineering a fully functional car within the time-span of one academic year, within the school of Mechanical Engineering. Naturally, the overall project involves a wide range of skills that exceed architectural training and the author is interested in this collaborative effort between two distinct departments and the logistics involved in its materialization.

scholarly journals A retrospective on hydrological modelling based on half a century with the HBV model

2021 ◽  
Author(s):  
Jan Seibert ◽  
Sten Bergström
Keyword(s):  
Water Resource Management ◽  
Model Development ◽  
Data Availability ◽  
Model Complexity ◽  
Management Planning ◽  
Wide Range ◽  
Modelling Studies ◽  
History Of ◽  
Hbv Model ◽  
Simple Models

Abstract. Hydrological models are important tools that are commonly used as the basis for water resource management planning. In the 1970s the development of several relatively simple models started and a number of so-called conceptual (or bucket-type) models were suggested. In these models, the complex and heterogeneous hydrological processes in a catchment are represented by a limited number of storage elements and fluxes between these. While a major motivation for such relatively simple models in the early days were computational limitations, today some of these models are still used frequently despite vastly increased computational opportunities. The HBV model, which was first applied about 50 years ago in Sweden, is a typical example of a conceptual catchment model and has gained large popularity over the past 50 years. During several model intercomparisons, the HBV model performed well despite (or because of) its relatively simple model structure. Here, the history of model development from thoughtful considerations of different model structures to modelling studies using hundreds of catchments and cloud computing facilities, is described. Furthermore, the wide range of model applications is discussed. The aim is to provide an understanding of the background of model development and a basis for addressing the balance between model complexity and data availability, which will face hydrologists also in the coming decades.

scholarly journals Neuromechanical interference of posture on movement: evidence from Alexander technique teachers rising from a chair

2014 ◽  
Vol 112 (3) ◽  
pp. 719-729 ◽  
Author(s):  
Timothy W. Cacciatore ◽  
Omar S. Mian ◽  
Amy Peters ◽  
Brian L. Day
Keyword(s):  
Center Of Mass ◽  
The Body ◽  
Task Instruction ◽  
Alexander Technique ◽  
Force Transmission ◽  
Range Of Movement ◽  
Wide Range ◽  
Weight Shift ◽  
Standing Up ◽  
Leg Extensors

While Alexander technique (AT) teachers have been reported to stand up by shifting weight gradually as they incline the trunk forward, healthy untrained (HU) adults appear unable to rise in this way. This study examines the hypothesis that HU have difficulty rising smoothly, and that this difficulty relates to reported differences in postural stiffness between groups. A wide range of movement durations (1–8 s) and anteroposterior foot placements were studied under the instruction to rise at a uniform rate. Before seat-off (SO) there were clear and profound performance differences between groups, particularly for slower movements, that could not be explained by strength differences. For each movement duration, HU used approximately twice the forward center-of-mass (CoM) velocity and vertical feet-loading rate as AT. For slow movements, HU violated task instruction by abruptly speeding up and rapidly shifting weight just before SO. In contrast, AT shifted weight gradually while smoothly advancing the CoM, achieving a more anterior CoM at SO. A neuromechanical model revealed a mechanism whereby stiffness affects standing up by exacerbating a conflict between postural and balance constraints. Thus activating leg extensors to take body weight hinders forward CoM progression toward the feet. HU's abrupt weight shift can be explained by reliance on momentum to stretch stiff leg extensors. AT's smooth rises can be explained by heightened dynamic tone control that reduces leg extensor resistance and improves force transmission across the trunk. Our results suggest postural control shapes movement coordination through a dynamic “postural frame” that affects the resistive behavior of the body.

Decoupled Stabilization of Spring-Mass Rigid-Body Locomotion

2011 ◽  
Author(s):  
Huan Hu ◽  
Justin Seipel
Keyword(s):  
Legged Locomotion ◽  
Humanoid Robots ◽  
The Body ◽  
Point Mass ◽  
Slip Model ◽  
In Series ◽  
General Force ◽  
Trunk Stabilization ◽  
Simple Models

Stable and reliable legged locomotion is critical for humans and humanoid robots. In the study of legged locomotion, simple models consisting of point-mass bodies and massless legs with telescoping actuators have been insightful. Several variants have been used, including the telescoping leg as a general force actuator [1], a simple passive linear or nonlinear spring [2], and a spring in series with a general force actuator [3]. These models serve as analogs that simplify the problem of understanding the mechanics of legged locomotion of real animals. One of defects of these simple models is the representation of the body by a point mass. Hence, trunk stabilization is not addressed. Nevertheless, this is a major problem in human and humanoid locomotion. In this study we propose a novel decoupled strategy to stabilize the trunk. First, we describe how this decoupled strategy works theoretically. Then, we present a case study based on the CT-SLIP model. Finally, we summarize the work and its expected impacts.

HIPEREMESIS GRAVIDARUM PADA IBU HAMIL DI KLINIK BIDAN SUPRIYATI SRIBIT BERBAH SLEMAN

2019 ◽  
Vol 14 (1) ◽  
pp. 51
Author(s):  
Pramukti Dian Setianingrum ◽  
Farah Irmania Tsani
Keyword(s):  
Blood Pressure ◽  
Pregnant Women ◽  
Hyperemesis Gravidarum ◽  
Unwanted Pregnancy ◽  
The Body ◽  
Nausea And Vomiting ◽  
Daily Activities ◽  
World Health ◽  
The World

Backgroud: The World Health Organization (WHO) explained that the number of Hyperemesis Gravidarum cases reached 12.5% of the total number of pregnancies in the world and the results of the Demographic Survey conducted in 2007, stated that 26% of women with live births experienced complications. The results of the observations conducted at the Midwife Supriyati Clinic found that pregnant women with hyperemesis gravidarum, with a comparison of 10 pregnant women who examined their contents there were about 4 pregnant women who complained of excessive nausea and vomiting. Objective: to determine the hyperemesis Gravidarum of pregnant mother in clinic. Methods: This study used Qualitative research methods by using a case study approach (Case Study.) Result: The description of excessive nausea of vomiting in women with Hipermemsis Gravidarum is continuous nausea and vomiting more than 10 times in one day, no appetite or vomiting when fed, the body feels weak, blood pressure decreases until the body weight decreases and interferes with daily activities days The factors that influence the occurrence of Hyperemesis Gravidarum are Hormonal, Diet, Unwanted Pregnancy, and psychology, primigravida does not affect the occurrence of Hyperemesis Gravidarum. Conclusion: Mothers who experience Hyperemesis Gravidarum feel nausea vomiting continuously more than 10 times in one day, no appetite or vomiting when fed, the body feels weak, blood pressure decreases until the weight decreases and interferes with daily activities, it is because there are several factors, namely, hormonal actors, diet, unwanted pregnancy, and psychology.

Creating the Wind

2020 ◽  
Vol 2 (4) ◽  
pp. 14-31
Author(s):  
Élodie Dupey García
Keyword(s):  
Indigenous Communities ◽  
The Body ◽  
Historical Sources ◽  
Natural Behavior ◽  
Sensory Experiences ◽  
Identity And Agency ◽  
Wide Range ◽  
Late Postclassic ◽  
Comparative Examination ◽  
Meteorological Phenomenon

This article explores how the Nahua of late Postclassic Mesoamerica (1200–1521 CE) created living and material embodiments of their wind god constructed on the basis of sensory experiences that shaped their conception of this divinized meteorological phenomenon. In this process, they employed chromatic and design devices, based on a wide range of natural elements, to add several layers of meaning to the human, painted, and sculpted supports dressed in the god’s insignia. Through a comparative examination of pre-Columbian visual production—especially codices and sculptures—historical sources mainly written in Nahuatl during the viceregal period, and ethnographic data on indigenous communities in modern Mexico, my analysis targets the body paint and shell jewelry of the anthropomorphic “images” of the wind god, along with the Feathered Serpent and the monkey-inspired embodiments of the deity. This study identifies the centrality of other human senses beyond sight in the conception of the wind god and the making of its earthly manifestations. Constructing these deity “images” was tantamount to creating the wind because they were intended to be visual replicas of the wind’s natural behavior. At the same time, they referred to the identity and agency of the wind god in myths and rituals.

Site specific agricultural soil management with the use of new technologies

2013 ◽  
Vol 16 (1) ◽  
pp. 59-67
Keyword(s):  
New Technologies ◽  
Digital Interface ◽  
Appropriate Treatment ◽  
Wide Range ◽  
Soil Variation ◽  
Soil Information ◽  
Remote Sensing Techniques ◽  
Agricultural Areas

<p>The Soil Science Institute of Thessaloniki produces new digitized Soil Maps that provide a useful electronic database for the spatial representation of the soil variation within a region, based on in situ soil sampling, laboratory analyses, GIS techniques and plant nutrition mathematical models, coupled with the local land cadastre. The novelty of these studies is that local agronomists have immediate access to a wide range of soil information by clicking on a field parcel shown in this digital interface and, therefore, can suggest an appropriate treatment (e.g. liming, manure incorporation, desalination, application of proper type and quantity of fertilizer) depending on the field conditions and cultivated crops. A specific case study is presented in the current work with regards to the construction of the digitized Soil Map of the regional unit of Kastoria. The potential of this map can easily be realized by the fact that the mapping of the physicochemical properties of the soils in this region provided delineation zones for differential fertilization management. An experiment was also conducted using remote sensing techniques for the enhancement of the fertilization advisory software database, which is a component of the digitized map, and the optimization of nitrogen management in agricultural areas.</p>

Hypothetical Role of Growth Factors to Reduce Intervertebral Disc Degeneration Significantly through Trained Biological Transformations

2020 ◽  
Vol 26 ◽  
Author(s):  
Cristian Muresanu ◽  
Siva G. Somasundaram ◽  
Sergey V. Vissarionov ◽  
Liliya V. Gavryushova ◽  
Vladimir N. Nikolenko ◽  
...  
Keyword(s):  
Growth Factors ◽  
Blood Circulation ◽  
Seminal Fluid ◽  
Prostate Gland ◽  
The Body ◽  
Personal Experiences ◽  
Biological Transformation ◽  
The Mind

Background: From the evidence of failed injection-based growth factor therapies, it has been proposed that a naturally triggered uninterrupted blood circulation of the growth factors would be superior. Objective: We seek to stimulate discussions and more research about the possibility of using the already available growth factors found in the prostate gland and endometrium by starting a novel educable physiology, known as biological transformations controlled by the mind. Methods: We summarized the stretch-gated ion channel mechanism of the cell membrane, and offer several practical methods that can be applied by anyone, in order to stimulate and enhance the blood circulation of the growth factors from the seminal fluid to sites throughout the body. This details the practical application of our earlier published studies about biological transformations. Results: A previously reported single-patient case study has been extended, adding more from his personal experiences continually improving this novel physiological training and extending the ideas from our earlier findings in detail. Conclusion: The biological transformation findings demonstrate the need additional research to establish the benefits of these natural therapies to repair and rejuvenate tissues affected by various chronic diseases or aging processes.

On the motion of bodies based on changes in the kinetic moment

2019 ◽  
Vol 20 (4) ◽  
pp. 267-275
Author(s):  
Yury N. Razoumny ◽  
Sergei A. Kupreev
Keyword(s):  
Center Of Mass ◽  
Stellar Dynamics ◽  
Elementary Particles ◽  
The Body ◽  
Accelerated Motion ◽  
Indirect Confirmation ◽  
Physical Principles ◽  
Two Bodies ◽  
Central Gravitational Field ◽  
Kinetic Moment

The controlled motion of a body in a central gravitational field without mass flow is considered. The possibility of moving the body in the radial direction from the center of attraction due to changes in the kinetic moment relative to the center of mass of the body is shown. A scheme for moving the body using a system of flywheels located in the same plane in near-circular orbits with different heights is proposed. The use of the spin of elementary particles is considered as flywheels. It is proved that using the spin of elementary particles with a Compton wavelength exceeding the distance to the attracting center is energetically more profitable than using the momentum of these particles to move the body. The calculation of motion using hypothetical particles (gravitons) is presented. A hypothesis has been put forward about the radiation of bodies during accelerated motion, which finds indirect confirmation in stellar dynamics and in an experiment with the fall of two bodies in a vacuum. The results can be used in experiments to search for elementary particles with low energy, explain cosmic phenomena and to develop transport objects on new physical principles.

Maintenance of Quantitative Genetic Variation

2018 ◽  
Author(s):  
Bruce Walsh ◽  
Michael Lynch
Keyword(s):  
Genetic Variation ◽  
Quantitative Genetics ◽  
Stabilizing Selection ◽  
Quantitative Genetic ◽  
Wide Range

One of the major unresolved issues in quantitative genetics is what accounts for the amount of standing genetic variation in traits. A wide range of models, all reviewed in this chapter, have been proposed, but none fit the data, either giving too much variation or too little apparent stabilizing selection.

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