Filter feeding in larvae of Simuliidae (Diptera: Culicomorpha): aspects of functional morphology and hydrodynamics

1982 ◽  
Vol 60 (4) ◽  
pp. 712-724 ◽  
Author(s):  
Douglas A. Craig ◽  
Mary M. Chance
Keyword(s):  
Water Flow ◽  
Body Shape ◽  
The Body ◽  
Larval Feeding ◽  
Cross Sectional ◽  
Simulium Vittatum ◽  
Optimal Flow ◽  
Flow Through ◽  
Sectional Shape ◽  
Opening And Closing

The feeding mechanism of simuliid larvae is further elucidated by detailed study of the nature and speed of cephalic fan and mouthpart movements, and examination of water flow around larvae. Photographic observations of artificial particles flowing past Simulium vittatum Zett. larvae show the body and head to be highly streamlined and water flow to be laminar over the larva. Dissections and cinephotography show cephalic fan closure to be initiated and controlled by rotation and medial movement of the torma. As the primary fan closes, the median and secondary fans close and form raised sides to the primary fan. Sharp movements made during opening and closing of the fan suggest the presence of "click mechanisms."One cephalic fan closes and adducts every 0.231 s, and for the period analyzed, one or other fan was closed 28% of the time. It is suggested that the time fans are closed should be included in calculations of simuliid larval feeding efficiencies. Larvae with slower mouthpart movements may filter more efficiently than those with faster movements.Laminar flow through and cross-sectional shape of fan rays produce optimal flow for filtration. Probably turbulent flow at higher velocity may explain observed decreases in feeding efficiencies. Behaviour, body shape, and structure of simuliid larvae are highly adapted for optimal water flow over body and fans, even when gross flow in the habitat is turbulent.

scholarly journals Determination of cross-sectional void fraction in a two-phase water flow through a PVC pipe

2021 ◽  
Vol 655 (1) ◽  
pp. 012024
Author(s):  
O.H. Ajesi ◽  
M.B. Latif ◽  
S.T. Gbenu ◽  
C. A. Onumejor ◽  
M. K. Fasasi ◽  
...  
Keyword(s):  
Water Flow ◽  
Void Fraction ◽  
Two Phase ◽  
Cross Sectional ◽  
Flow Through ◽  
Pvc Pipe ◽  
Phase Water

Factors Controlling the Change of Shape of Certain Nemertean and Turbellarian Worms

1958 ◽  
Vol 35 (4) ◽  
pp. 731-748 ◽  
Author(s):  
R. B. CLARK ◽  
J. B. COWEY
Keyword(s):  
Water Conservation ◽  
Ecological Factors ◽  
Longitudinal Axis ◽  
The Body ◽  
Cross Sectional ◽  
Ciliary Action ◽  
Theoretical Predictions ◽  
Observed Behaviour ◽  
Body Wall Musculature ◽  
Sectional Shape

1. Nemerteans and turbellarians have an inextensible fibre system around them in the form of a lattice of left- and right-handed spirals. The effect of this system on the change of shape on these worms has been analysed theoretically and compared with the observed behaviour of nine species of turbellarian and nemertean from widely differing habitats. 2. The following theoretical relationships have been studied: (a) Variation of the angle between the geodesics and the longitudinal axis of the worm during changes in length, and the role of the fibre system in limiting changes in length of the animal. (b) The change in cross-sectional shape during changes in length. (c) The extension of the fibres and the extensibility of the worms, assuming the fibres of the lattice to be elastic. 3. The species investigated conform with the theoretical predictions to varying degrees and have been grouped accordingly: (a) Geonemertes dendyi and Rhynchodemus bilineatus have low extensibilities and fit the prediction well. They are nearly circular in cross-section at all lengths as a result of their low extensibility and this is related to their terrestrial habit and need for water conservation. (b) Amphiporus lactifloreus, Lineus gesserensis and L. longissimus are moderately flattened in the relaxed position and have extensibilities between 6 and 10. They are marine crawling forms using cilia for locomotion and so must present a fairly large ciliated surface to the substratum. The fibre system does not limit contraction; the compression of the epithelial cells causes the observed extensibilities to fall a little short of the theoretical values. (c) Cerebratulus lacteus, Malacobdella grossa, Polycelis nigra and Dendrocoelum lacteum are very flattened forms and have very high theoretical extensibilities, but very low observed ones. The factors causing this are the thickness of the body-wall musculature (Cerebratulus), the limiting effect of longitudinal and circular reticulin fibres in the muscle layers, and the presence of dorso-ventral and diagonal muscles. Their flattened form is correlated with ecological factors (with swimming in Cerebratulus, with its parasitic life in the mantle of bivalves in Melacobdella) or with physical ones in turbellarians where a permanently flattened form is necessary for these worms to move by ciliary action.

scholarly journals PARENTS BODY SHAPE PROFILE AND OVERWEIGHT AMONG STUDENTS AT SINGKAWANG ADVENTIST SCHOOL

2019 ◽  
Vol 7 (1) ◽  
pp. 17-32
Author(s):  
Sultan Fredyansyah Bagaskara Djula ◽  
Sapti Widyarti Djula
Keyword(s):  
Body Mass Index ◽  
Body Weight ◽  
Body Mass ◽  
Significant Relationship ◽  
Body Shape ◽  
Body Height ◽  
The Body ◽  
School Students ◽  
Cross Sectional ◽  
Overweight Or Obesity

Introduction: When both parents are obesity, thus the children are 80% potentially become overweight or obesity. If one of the parent is overweight or obesity, thus the children are 40% potentially to become overweight or obesity. The purpose of the study is to analyze is there any significant relationship between parents’ body shape with overweight among students at Singkawang Adventist School.  Method: The method of the study is descriptive with quantitative method and the cross sectional design. Sampling technique is total sampling among the overweight students. Number of respondens are 35 persons which have been measure body height, body weight and determined Body Mass Index (BMI). Data processing using SPSS Program.  Result: The results of the study show that the status of overweight students is obesity and parents’ body shape are overweight (there is no significant relationship between obesity in adolescents with the body shape of the father with a significance of (0.086) with a ρ value> 0.05 as well as no significant relationship between obesity in adolescents with the body shape of their mothers, with a significance of  (0.411) with ρ value> 0.005). There is no significant relationship between overweight students with parents’ body shape. There is not enough evidence to refuse null hypothesis.  Disscussion: Recommendation are given to Singkawang Adventist School Students in order to maintain a healthy lifestyle and give effort to reduce body weight. To the next researcher to do research with bigger sample size.   Keywords : overweight, obesity, Body Mass Index(BMI), body shape 

The Structure and Function of the Basement Membrane Muscle System in Amphiporus lactifloreus (Nemertea)

1952 ◽  
Vol s3-93 (21) ◽  
pp. 1-15
Author(s):  
J. B. COWEY
Keyword(s):  
Basement Membrane ◽  
Cross Section ◽  
Circular Cross Section ◽  
The Body ◽  
Minimum Length ◽  
Muscle Fibres ◽  
Body Volume ◽  
Cross Sectional ◽  
Elliptical Cross ◽  
Sectional Shape

The body wall of A. lactifloreus has the following structure from the outside inwards. (i) A basement membrane of five to six layers immediately underlying the epithelium. Each layer consists of right-hand and left-hand geodesic fibres making a lattice, whose constituent parallelograms have a side length of from 5 to 6µ. The fibres are attached to one another where they cross; so there can be no slipping relative to one another. (ii) A layer of circular muscle-fibres running round the animal containing two systems of argyrophil fibres--one of fibres at intervals of 10µ. running parallel to the muscle-fibres and the other of fibres running radially through the layer from the basement membrane to the myoseptum. (iii) A myoseptum which is identical in structure with a single layer of the basement membrane (iv) A layer of longitudinal muscle, whose fibres are arranged in layers on each side of a series of longitudinal radial membranes. Membranes identical in structure with the basement membrane invest the nerve cords, the gut, the gonads, and the proboscis. The interrelations of argyrophil and muscle-fibres in the muscle layers is described and their functioning discussed. The system of inextensible geodesic fibres is analysed from a functional standpoint. The maximum volume enclosed by a cylindrical element (cross-section circular), of such a length that the geodesic makes one complete turn round it, varies with the value of the angle θ between the fibres and the longitudinal axis. When θ is 0° the volume is zero; it increases to a maximum when θ is 54° 44' and decreases again to zero when θ is 90°. The length of the element under these conditions varies from zero when θ is 90° to a maximum (the length of one turn of the geodesic) when θ is 0°. The body-volume of the worm is constant. Thus it has a maximum and minimum length when its cross-section is circular, and at any length between these values its cross-section becomes more or less elliptical. It is maximally elliptical when θ is 54° 44', i.e. when the volume the system could contain, at circular cross-section, is maximal. From measurements of the ratio of major to minor axes of this maximally elliptical cross-section, the maximum and minimum lengths of the worm relative to the relaxed length and values of θ at maximum and minimum length are calculated. The worm is actually unable to contract till its cross-section is circular; but measurements of its cross-sectional shape at the minimum length it can attain, permit calculation of the theoretical length and value of θ for this cross-sectional shape. Calculated values of length and the angle 6 agree well with the directly observed values.

scholarly journals HUBUNGAN ANTARA BODY IMAGE DAN PERILAKU MAKAN DENGAN STATUS GIZI REMAJA PUTRI DI SMA THERESIANA SEMARANG

2012 ◽  
Vol 1 (1) ◽  
pp. 398-404
Author(s):  
Nur Widianti ◽  
Aryu Candra Kusumastuti
Keyword(s):  
Body Image ◽  
Nutritional Status ◽  
Eating Behavior ◽  
Body Shape ◽  
Group Discussion ◽  
Eating Behaviour ◽  
Simple Random Sampling ◽  
The Body ◽  
Female Adolescents ◽  
Cross Sectional

Background: The dissatisfaction with their body shapes is commonly found among female adolescents. The lack of the contentment lead them to gain an ideal body shape but, unfortunately, they implement improper eating behaviour. The extreme diet they have affects negatively to their nutritional status. This study was aimed at analyzing the association between the body image and eating behaviour with nutritional status of female adolescents. Methods: The study was cross-sectional on 72 female students of grade X, XI and XII in Theresiana Senior High School Semarang. The samples were taken based on simple random sampling. The samples were fulfilled inclusive criterion. The data were gathered by using questionnaires and focus group discussion (FGD). The FGD was intended to find more data on body image. Nutritional status data was obtained by measuring weight and height.  Then, z-score was calculated based on BMI/ U by using WHO Anthro Plus 2007. Results: A total of 29 subjects (40.3%) were not satisfied with their body shape and 43 subjects (59.7%) were satisfied with their body shape. The majority (56.9%) subjects have not good eating behavior yet, whereas 43.1 % of them have good eating behavior. There were significant association between body image with nutritional status (r = 0.482 p = 0.001) and eating behavior with nutritional status (r = 0.507 p = 0.001). Conclusion: Body image and the eating behavior were associated with nutritional status of female adolescents.

scholarly journals Pilot study about the micro hydropower generation by use of flow induced vibration phenomenon

2018 ◽  
Vol 180 ◽  
pp. 02122
Author(s):  
Yoshifumi Yokoi
Keyword(s):  
Power Generation ◽  
The Body ◽  
Flow Induced Vibration ◽  
Cross Sectional ◽  
Generation Characteristic ◽  
Micro Power ◽  
Power Generation System ◽  
Sectional Shape ◽  
Body Section ◽  
Piezo Electric

In order to construct a micro power generation system using a piezo-electric element, power generation was tried using excitation oscillation of the bluff cylinder by the vortex shedding from the bluff cylinder. The bluff cylinder consists of a board spring section in which the piezo-electric element was attached, and a body section. The bluff cylinder was inserted into the water flow, the shape and the submersion depth of the bluff cylinder, and the flow velocity were varied, and the power generation characteristic was investigated. As a result, it was found that it can generate electricity by vortex excitation. It was found that the length and the submersion depth of the body section influence power generation. It was shown that the power generation characteristic changes with cross-sectional shape of the bluff cylinder. The most suitable state was the case where the submersion depth was set to 140 mm with a circular cylinder with a span length of 250 mm. It is important to choose the power generation object which suited the use purpose.

scholarly journals Multi-branching three-dimensional flow with substantial changes in vessel shapes

2008 ◽  
Vol 614 ◽  
pp. 329-354 ◽  
Author(s):  
R. I. BOWLES ◽  
N. C. OVENDEN ◽  
F. T. SMITH
Keyword(s):  
Three Dimensional ◽  
Longitudinal Vortex ◽  
Cross Sectional ◽  
Flow Rates ◽  
Relative Flow Rate ◽  
Wide Range ◽  
Flow Through ◽  
Sectional Shape ◽  
Area Expansion ◽  
Reversed Motion

This theoretical investigation of steady fluid flow through a rigid three-dimensional branching geometry is motivated by applications to haemodynamics in the brain especially, while the flow through a tube with a blockage or through a collapsed tube provides another motivation with a biomedical background. Three-dimensional motion without symmetry is addressed through one mother vessel to two or several daughters. A comparatively long axial length scale of the geometry leads to a longitudinal vortex system providing a slender-flow model for the complete mother-and-daughters flow response. Computational studies and subsequent analysis, along with comparisons, are presented. The relative flow rate varies in terms of an effective Reynolds number dependence, allowing a wide range of flow rates to be examined theoretically; also any rigid cross-sectional shape and ratio of cross-sectional area expansion or contraction from the mother vessel to the daughters can be accommodated in principle in both the computations and the analysis. Swirl production with substantial crossflows is found. The analysis shows that close to any carina (the ridge separating daughter vessels) or carinas at a branch junction either forward or reversed motion can be observed locally at the saddle point even though the bulk of the motion is driven forward into the daughters. The local forward or reversed motion is controlled, however, by global properties of the geometry and incident conditions, a feature which applies to any of the flow rates examined.

scholarly journals Self-perception of body image in college students of a nutrition course

2020 ◽  
Vol 8 (5) ◽  
pp. 83-94
Author(s):  
Celenia Raquel Monteiro de Aguiar ◽  
Carlos Alberto Alves Dias Filho ◽  
Andressa Coelho Ferreira ◽  
Ilka Kassandra Pereira Belfort ◽  
Sally Cristina Moutinho Monteiro
Keyword(s):  
Body Image ◽  
Body Shape ◽  
Cross Sectional Study ◽  
The Body ◽  
P Value ◽  
Sectional Study ◽  
Image Perception ◽  
Cross Sectional ◽  
Nutrition Course ◽  
Perception Disorder

Objective: To evaluate the body image of university students in the course of nutrition. Materials and methods: A cross-sectional study was carried out with 181 students of both genders from the Nutrition Undergraduate of Maranhão, Brazil. The presence and degree of dissatisfaction with body shape were evaluated by Body Shape Questionnaire (BSQ 34), another instrument used in this study was Body Figure Silhouettes (BFS). Results: The participants presented mean age of 23.1 (±5.2) years, majority women (89.5%). Most of the subjects were eutrophic (66.9%) according to BMI, and no image perception disorder according to BSQ34. According to the BSF, 56 students had the silhouette represented by figure 4, however, the figure most desired by 111 students was demonstrated by silhouette 3, (p-value 0.000). Demonstrating the desire for weight loss of the majority, despite being represented by a silhouette eutrophic. Conclusion: Most (66.9%) eutrophic, according to BMI and without image disturbances (54.7%) according to BSQ 34. However, there is a trend of overweight and obese individuals presenting with image disorders.

Supersonic Flow Past Slender Bodies With Discontinuous Profile Slope

1955 ◽  
Vol 6 (2) ◽  
pp. 114-124 ◽  
Author(s):  
L. E. Fraenkel ◽  
H. Portnoy
Keyword(s):  
Internal Flow ◽  
Leading Edge ◽  
Rate Of Change ◽  
The Body ◽  
Cross Sectional ◽  
Slender Body Theory ◽  
Bodies Of Revolution ◽  
Slender Bodies ◽  
External Forces ◽  
Sectional Shape

SummaryWard’s slender-body theory is extended to derive first approximations to the external forces on slender bodies of general cross section with discontinuous profile slope. Two classes of body are considered: bodies whose profile (typified by the local radius) is continuous between the nose and base, and certain bodies whose profile is discontinuous, such as bodies with annular or side air intakes and wing-bodies on which the wing has an unswept leading edge. (Where air intakes are concerned, it is assumed that they are sharp-edged and that there is no “ spillage ” of the internal flow).The following conclusions apply to the former class of bodies. The variation of drag with Mach number is found to depend only on the discontinuities in the longitudinal rate of change of the cross-sectional area, and is thus independent of cross-sectional shape. The drag itself is unchanged if the direction of the flow is reversed. The expressions for lift and moment assume the same forms as for smooth pointed bodies, the lift depending only on conditions at the base of the body.The general theory is applied to winged bodies of revolution with an unswept wing leading edge: the results bear a marked resemblance to those obtained by Ward. The results for wings alone are seen to be applicable, with one modification, to subsonic as well as to supersonic speeds.

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