scholarly journals The natural selection of metabolism and mass selects allometric transitions from prokaryotes to mammals

2016 ◽  
Author(s):  
Lars Witting
Keyword(s):  
Natural Selection ◽  
Body Mass ◽  
Three Dimensional ◽  
The Body ◽  
Net Energy ◽  
A Value ◽  
Spatial Dimensions ◽  
Self Replication ◽  
Selection Of ◽  
Evolution Proceeds

AbstractInter-specific body mass allometries can evolve from the natural selection of mass, with ±1/4 and ±3/4 exponents following from the geometry of intra-specific interactions when density dependent foraging occurs in two spatial dimensions (2D, Witting, 1995). The corresponding values for three dimensional interactions (3D) are ±1/6 and ±5/6.But the allometric exponents in mobile organisms are more diverse than the prediction. The exponent for mass specific metabolism tends to cluster around −1/4 and −1/6 in terrestrial and pelagic vertebrates, but it is strongly positive in prokaryotes with an apparent value around 5/6 (DeLong et al., 2010). And a value around zero has been reported in protozoa, and on the macro evolutionary scale from prokaryotes over larger unicells to multicellular vertebrates (Makarieva et al., 2005, 2008).I show that mass specific metabolism can be selected as the pace of the resource handling that generates net energy for self-replication and the selection of mass, and that this selection of metabolism and mass is sufficient to explain metabolic exponents that decline from 5/6 over zero to −1/6 in 3D, and from 3/4 over zero to −1/4 in 2D. The decline follows from a decline in the importance of mass specific metabolism for the selection of mass, and it suggestsi) that the body mass variation in prokaryotes is selected from primary variation in mass specific metabolism,ii) that the variation in multicellular animals are selected from primary variation in the handling and/or densities of the underlying resources,iii) that protozoa are selected as an intermediate lifeform between prokaryotes and multicellular animals, andiv) that macro evolution proceeds along an upper bound on mass specific metabolism.

scholarly journals The natural selection of metabolism and mass selects lifeforms from viruses to multicellular animals

2016 ◽  
Author(s):  
Lars Witting
Keyword(s):  
Life History ◽  
Natural Selection ◽  
Sexual Reproduction ◽  
Metabolic Pathways ◽  
Net Energy ◽  
Major Life ◽  
Self Replication ◽  
Lower Size ◽  
Initial Selection ◽  
Selection Of

AbstractI show that the natural selection of metabolism and mass is selecting for the major life history and allometric transitions that define lifeforms from viruses, over prokaryotes and larger unicells, to multicellular animals with sexual reproduction.The proposed selection is driven by a mass specific metabolism that is selected as the pace of the resource handling that generates net energy for self-replication. This implies that an initial selection of mass is given by a dependence of mass specific metabolism on mass in replicators that are close to a lower size limit. A maximum dependence that is sublinear is shown to select for virus-like replicators with no intrinsic metabolism, no cell, and practically no mass. A maximum superlinear dependence is instead selecting for prokaryote-like self-replicating cells with asexual reproduction and incomplete metabolic pathways. These self-replicating cells have selection for increased net energy, and this generates a gradual unfolding of a population dynamic feed-back selection from interactive competition. The incomplete feed-back is shown to select for larger unicells with more developed metabolic pathways, and the completely developed feed-back to select for multicellular animals with sexual reproduction.This model unifies natural selection from viruses to multicellular animals, and it provides a parsimonious explanation where allometries and major life history transitions evolve from the natural selection of metabolism and mass.

Practical Application of the Similarity Law of Structures in the Reconstruction of the Surface Layer of Bricks

2021 ◽  
Vol 1017 ◽  
pp. 21-30
Author(s):  
Victor Danilov ◽  
Arkady Ayzenshtadt ◽  
Maria Frolova
Keyword(s):  
Surface Layer ◽  
Experimental Studies ◽  
Calcium Content ◽  
Degradation Process ◽  
The Body ◽  
Atmospheric Water ◽  
A Value ◽  
Architectural Monument ◽  
Similarity Law ◽  
Selection Of

This paper discusses the results of experimental studies on the selection of the repair mixture compound for recreating the surface layer of the historical brick of the 18th century architectural monument “Commercial Bank” in Arkhangelsk. According to the research results, it was found that the historical brick has a relatively higher density and increased calcium content than the modern one. The characteristics of the surfaces of the analyzed materials based on the component indicators of specific surface energy showed that the brick of 1859, characterized by the highest degree of destruction, has the maximum value of the polar energy component. This fact may indicate a greater hydrophilicity of the surface in relation to atmospheric water and, as a result, a more intensive degradation process. It is established that the composition of the repair mixture with the addition of brick crumbs in the amount of 50 % has a value of the polar part of the surface tension equal to similar parameters for historical bricks (1786 and 1859) after their preliminary priming. The use of this mixture to recreate the surface layer of the brick will allow atmospheric water to pass freely through the repair compound and the body of the brick, without concentrating on the interface and without causing its destruction and detachment when drying.

scholarly journals Selection of the characteristics of the suspension system of the high-speed tracked robot

2021 ◽  
Vol 1 (2) ◽  
pp. 63-70
Author(s):  
YE.B. Sarach ◽  
◽  
YA.A. Tkachev ◽  
M.E. Krokhin ◽  
◽  
...  
Keyword(s):  
High Speed ◽  
Natural Frequencies ◽  
Resonant Mode ◽  
Suspension System ◽  
The Body ◽  
Suspension Systems ◽  
A Value ◽  
Dirt Road ◽  
Suspension Stiffness ◽  
Selection Of

Currently, the field of mechanical engineering is rapidly developing, including the creation of robotic high-speed vehicles. The design of suspension systems for such vehicles must be accompa-nied by the fulfillment of certain requirements, which are currently not formulated. Considering the thing that there is no person in the body of a high-speed robot, the application of the requirements for the suspensions of crew vehicles is not justified. In order to develop recommendations on the choice of characteristics of suspension systems for high-speed tracked robots, the research objects, which mass is in the range from 1000 to 10000 kg are determined. No suspension system is required for objects weighing less than 1000 kg. Objects weighing more than 10,000 kg will be created on the basis of existing serial vehicles. The study is based on the provision that the considered class of vehicles is not subject to re-strictions on the range of natural frequencies of body vibrations. Considering that one of the main requirements remains for high-speed tracked robots - ensuring a high average speed, it is proposed to increase the suspension stiffness in order to exclude resonance from the range of possible travel speeds. Using the accepted provisions, a study of the suspension system of increased stiffness is carried out. The movement along the tracks of a harmonic profile in resonance mode and a broken dirt road is simulated. The results of the study show that the characteristics of the suspension system, selected accord-ing to the proposed method, make it possible to move along the line of the harmonic profile in the resonant mode without suspension breakdowns. The speed of movement on a broken dirt road is limited to a value, which exceeding leads to sig-nificant vibrations of the body and an increase in the load on the elements of the suspension system. The absence of breakdowns leads to a decrease in the loading of the suspension, which makes it possible to reduce the mass of its elements.

scholarly journals The natural selection of metabolism explains curvature in fossil body mass evolution

2016 ◽  
Author(s):  
Lars Witting
Keyword(s):  
Natural Selection ◽  
Body Mass ◽  
Full Range ◽  
Life Forms ◽  
Maximum Mass ◽  
Niche Evolution ◽  
Major Life ◽  
Terrestrial Mammals ◽  
Predicted Values ◽  
Selection Of

AbstractThe natural selection of metabolism and mass can explain inter-specific allometries from prokaryotes to mammals (Witting 2017a), with exponents that depend on the selected metabolism and the spatial dimensionality (2D/3D) of intra-specific behaviour. The predicted 2D-exponent for total metabolism increases from 3/4 to 7/4 when the fraction of the inter-specific body mass variation that follows from primary variation in metabolism increases from zero to one.A 7/4 exponent for mammals has not been reported from inter-specific comparisons, but I detect the full range of allometries for evolution in the fossil record. There are no fossil data for allometric correlations between metabolism and mass, but I estimate life history allometries from the allometry for the rate of evolution in mass (w) in physical time (t).The exponent describes the curvature of body mass evolution, with predicted values being: 3/2 (2D) for within niche evolution in small horses over 54 million years. 5/4 (2D) and 9/8 (3D) for across niche evolution of maximum mass in four mammalian clades. 3/4 (2D) for fast evolution in large horses, and maximum mass in trunked and terrestrial mammals. 1 for maximum mass across major life-forms during 3.5 billion years of evolution along a metabolic bound.

scholarly journals BODY-MASS ESTIMATION IN PALEONTOLOGY: A REVIEW OF VOLUMETRIC TECHNIQUES

2016 ◽  
Vol 22 ◽  
pp. 133-156 ◽  
Author(s):  
Charlotte A. Brassey
Keyword(s):  
Body Mass ◽  
Laser Scanning ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
The Body ◽  
Estimation Methods ◽  
Mass Estimation ◽  
Surface Laser ◽  
Body Mass Estimation ◽  
Future Work

AbstractBody mass is a key parameter for understanding the physiology, biomechanics, and ecology of an organism. Within paleontology, body mass is a fundamental prerequisite for many studies considering body-size evolution, survivorship patterns, and the occurrence of dwarfism and gigantism. The conventional method for estimating fossil body mass relies on allometric scaling relationships derived from skeletal metrics of extant taxa, but the recent application of three-dimensional imaging techniques to paleontology (e.g., surface laser scanning, computed tomography, and photogrammetry) has allowed for the rapid digitization of fossil specimens. Volumetric body-mass estimation methods based on whole articulated skeletons are therefore becoming increasingly popular. Volume-based approaches offer several advantages, including the ability to reconstruct body-mass distribution around the body, and their relative insensitivity to particularly robust or gracile elements, i.e., the so-called ‘one bone effect.’ Yet their application to the fossil record will always be limited by the paucity of well-preserved specimens. Furthermore, uncertainties with regards to skeletal articulation, body density, and soft-tissue distribution must be acknowledged and their effects quantified. Future work should focus on extant taxa to improve our understanding of body composition and increase confidence in volumetric model input parameters.

Influence of detectability and ability to escape on natural selection of conspicuous autotomous defenses

1991 ◽  
Vol 69 (3) ◽  
pp. 757-764 ◽  
Author(s):  
William E. Cooper Jr. ◽  
Laurie J. Vitt
Keyword(s):  
Natural Selection ◽  
Simple Model ◽  
Conditional Probability ◽  
Body Part ◽  
Probability Of Detection ◽  
The Body ◽  
Body Parts ◽  
Lizard Species ◽  
Predator Prey ◽  
Selection Of

Antipredatory adaptations in which a predator's attack is diverted to body parts that may be sacrificed or are less vulnerable sometimes depend upon the conspicuousness of the body part attacked. The predator's attention is drawn to the emphasized part, which serves as a decoy. Such defenses appear paradoxical in that they increase the probability of detection. However, they simultaneously increase the probability of postdetectional escape enough to decrease the overall probability of being killed. Based on probabilities of detection and of escape following detection, a simple model predicts the conditions in which autotomy and related defenses are favored. For a conspicuous decoy, equilibrium values of the increases in probabilities of detection and of escape following detection are given. Data on the conditional probability of escape after detection are discussed for the scincid lizards Eumeces fasciatus and E. laticeps, which have brightly colored autotomous tails. Versions of the model that split the predator–prey encounter into several successive stages are outlined briefly and illustrated by the data for the two lizard species. Strategies for measuring the probabilities and testing the model's predictions are considered.

scholarly journals Modeling the pigs body mass growth and the stressing factors impact on the daily feed intake

2005 ◽  
Vol 53 (5) ◽  
pp. 105-116 ◽  
Author(s):  
Ludvík Novák ◽  
Ladislav Zeman ◽  
Pavel Novák ◽  
Petr Mareš
Keyword(s):  
Body Mass ◽  
Growth Curve ◽  
Feed Intake ◽  
The Body ◽  
Metabolizable Energy ◽  
Net Energy ◽  
Feed Mixture ◽  
Mass Growth ◽  
The Impact ◽  
Mass Increase

Modeling the body mass growth in fattened pigs by means of the exponential growth function enables to simulate the growth curve from three constants of the gender’s, or the hybrid’s combination, represented by their body mass phenotype: body mass at birth (G0) genetic limit of body mass (GLi) and the maximum body mass increase reached in the inflexion of the growth curve (dG max). However the expression of animalęs genome to its body mass phenotype depends on the amount and quality of the feed mixture consumed and mainly on the fact how much of the net energy gained remains left for production (NEp), after the mandatory needs of the body maintenance functions are saturated. Only this amount of net energy for production may be deposited into the proteins and fats of the body mass increase (dG/ dt). The net energy for production (NEp) is restricted; if a greater amount of net energy gained (NE) is spend, for compensation of the stressors impact (NE stx). The sum of particular stressor’s action is expressed by stressor’s index (STX) and indicates the proportional increase of net energy (NE) spend for the maintenance requirement of the animal (NEm). This contribution extends, the classic method of modeling the body mass growth, by the simultaneous modeling of the daily feed mixture intake (DFI) with the content of metabolizable energy (SMEF). The daily feed intake is calculated with respect to the impact of stressors on the net energy consumption. The setting of the model automatically increases the amount of the daily feed intake, so that the adequate amount of net energy for production will not be disturbed. The basic equation for the appropriate daily feed intake sounds as followDFI = (NEp + (STX + 1). BM) / (0,6 SMEF) [kg/d]. the BM=0,3.G¾ [MJ/d]Details for calculation, of the net energy for production (NEp) from the input values of the body mass phenotype (G0, GLi, dG max), the content of the metabolizable energy in the feed (SMEF) and of the stressors index value (STX), are described. The validation of the method developed has been approved using the experimental data gained in the fattening of 33 pigs, both sexes, of PIC hybrid combination. The animals were fattened with the standard feed mixture TESTA in a controlled condition of stable’s climate and appropriate stockbreeder’s and veterinary care.

scholarly journals The Correlation of Body Mass Index (BMI) and Stress Level with Menstrual Cycle of Young Women at Senior Vocational High School Widya Utama Indramayu

2018 ◽  
Vol 5 (2) ◽  
pp. 47-53
Author(s):  
Ani Nurhaeni ◽  
Putri Gayuh Uthami ◽  
Tutin Marlia
Keyword(s):  
Body Mass Index ◽  
Menstrual Cycle ◽  
Body Mass ◽  
Young Women ◽  
Stress Level ◽  
Significant Relationship ◽  
The Body ◽  
Depression Anxiety Stress Scale ◽  
A Value ◽  
Normal Category

Background:Reproductive health is an important part of the health program. Several diseases that related to the reproductive system are important things to be solved such as irregular menstrual cycles. Some factors that affect the menstrual cycle are the influence of weight, physical activity, and the process of ovulation and adequate luteal function. Now, special attentions arealso emphasized on the diet behavior and stress.  The purpose of this study was to know the correlation of Body Mass Index (BMI) and stress level with menstrual cycle of young women in SMK WidyaUtama Indramayu. Methods: The design of this study used an analytic survey using a cross sectional design. The instrument used is the questionnaire of Depression Anxiety Stress Scale (DASS) that has been standardized and modified. questionnaire for measuring the menstrual cycle is a question about the menstrual cycle. Body mass index (BMI) is measured by calculating body weight / TB2 in kg / m2. Result: The results showed that the Body Mass Index in Normal category (68.3%), stress level in the normal category (68.3% and menstrual cycle in the normal category (56.7%). There was a significant relationship between body mass index and cycle menstruation with a value of p = 0.000 There is a significant relationship between stress levels with the menstrual cycle with a value of p = 0.031. Conclusion: that need to be recommended are the need to control the weight so that the nutritional status will be in the ideal level, able to adapt the stress and regularly record the menstrual period in order to control the menstrual cycle.

Application of the Joint Coordinate System to Three-Dimensional Joint Attitude and Movement Representation: A Standardization Proposal

1993 ◽  
Vol 115 (4A) ◽  
pp. 344-349 ◽  
Author(s):  
G. K. Cole ◽  
B. M. Nigg ◽  
J. L. Ronsky ◽  
M. R. Yeadon
Keyword(s):  
Coordinate System ◽  
Three Dimensional ◽  
Axial Rotation ◽  
Distal Segment ◽  
The Body ◽  
Proximal Segment ◽  
Practical Applications ◽  
Flexion Extension ◽  
Joint Coordinate System ◽  
Selection Of

The selection of an appropriate and/or standardized method for representing 3-D joint attitude and motion is a topic of popular debate in the field of biomechanics. The joint coordinate system (JCS) is one method that has seen considerable use in the literature. The JCS consists of an axis fixed in the proximal segment, an axis fixed in the distal segment, and a “floating” axis. There has not been general agreement in the literature on how to select the body fixed axes of the JCS. The purpose of this paper is to propose a single definition of the body fixed axes of the JCS. The two most commonly used sets of body fixed axes are compared and the differences between them quantified. These differences are shown to be relevant in terms of practical applications of the JCS. Argumentation is provided to support a proposal for a standardized selection of body fixed axes of the JCS consisting of the axis eˆ1 embedded in the proximal segment and chosen to represent flexion-extension, the “floating” axis eˆ2 chosen to represent ad-abduction, and the axis eˆ3 embedded in the distal segment and chosen to represent axial rotation of that segment. The algorithms for the JCS are then documented using generalized terminology.

Sign in / Sign up

Export Citation Format

Share Document