scholarly journals Natural barriers: waterfall transit by small flying animals

2020 ◽  
Vol 7 (8) ◽  
pp. 201185
Author(s):  
Victor M. Ortega-Jimenez ◽  
Eva C. Herbst ◽  
Michelle S. Leung ◽  
Robert Dudley
Keyword(s):  
Complex Dynamics ◽  
Sister Group ◽  
The Body ◽  
Heterogeneous Structure ◽  
Flight Behaviour ◽  
Physical Constraints ◽  
Physical Barriers ◽  
Translational Speed ◽  
Geomorphological Features ◽  
Stroke Amplitude

Waterfalls are conspicuous geomorphological features with heterogeneous structure, complex dynamics and multiphase flows. Swifts, dippers and starlings are well-known to nest behind waterfalls, and have been reported to fly through them. For smaller fliers, by contrast, waterfalls seem to represent impenetrable barriers, but associated physical constraints and the kinematic responses of volant animals during transit are unknown. Here, we describe the flight behaviour of hummingbirds (the sister group to the swifts) and of various insect taxa as they fly through an artificial sheet waterfall. We additionally launched plastic balls at different speeds at the waterfall so as to assess the inertial dependence of sheet penetration. Hummingbirds were able to penetrate the waterfall with reductions in both their translational speed, and stroke amplitude. The body tilted more vertically and exhibited greater rotations in roll, pitch and yaw, along with increases in tail spread and pitch. The much smaller plastic balls and some flies moving at speeds greater than 2.3 m s −1 and 1.6 m s −1 , respectively, also overcame effects of surface tension and water momentum and passed through the waterfall; objects with lower momentum, by contrast, entered the sheet but then fell along with the moving water. Waterfalls can thus represent impenetrable physical barriers for small and slow animal fliers, and may also serve to exclude both predators and parasites from nests of some avian taxa.

A new species of Largocephalosaurus (Diapsida: Saurosphargidae), with implications for the morphological diversity and phylogeny of the group

2013 ◽  
Vol 151 (1) ◽  
pp. 100-120 ◽  
Author(s):  
CHUN LI ◽  
DA-YONG JIANG ◽  
LONG CHENG ◽  
XIAO-CHUN WU ◽  
OLIVIER RIEPPEL
Keyword(s):  
New Species ◽  
Type Species ◽  
Morphological Diversity ◽  
Transverse Process ◽  
Sister Group ◽  
The Body ◽  
Current Evidence ◽  
Diagnostic Features ◽  
Additional Information ◽  
A New Species

AbstractLargocephalosaurus polycarpon Cheng et al. 2012a was erected after the study of the skull and some parts of a skeleton and considered to be an eosauropterygian. Here we describe a new species of the genus, Largocephalosaurus qianensis, based on three specimens. The new species provides many anatomical details which were described only briefly or not at all in the type species, and clearly indicates that Largocephalosaurus is a saurosphargid. It differs from the type species mainly in having three premaxillary teeth, a very short retroarticular process, a large pineal foramen, two sacral vertebrae, and elongated small granular osteoderms mixed with some large ones along the lateral most side of the body. With additional information from the new species, we revise the diagnosis and the phylogenetic relationships of Largocephalosaurus and clarify a set of diagnostic features for the Saurosphargidae Li et al. 2011. Largocephalosaurus is characterized primarily by an oval supratemporal fenestra, an elongate dorsal ‘rib-basket’, a narrow and elongate transverse process of the dorsal vertebrae, and the lack of a complete dorsal carapace of osteoderms. The Saurosphargidae is distinct mainly in having a retracted external naris, a jugal–squamosal contact, a large supratemporal extensively contacting the quadrate shaft, a leaf-like tooth crown with convex labial surface and concave lingual surface, a closed dorsal ‘rib-basket’, many dorsal osteoderms, a large boomerang-like or atypical T-shaped interclavicle. Current evidence suggests that the Saurosphargidae is the sister-group of the Sauropterygia and that Largocephalosaurus is the sister-group of the Saurosphargis–Sinosaurosphargis clade within the family.

The Japanese Village in the Seventeenth Century

1952 ◽  
Vol 12 (1) ◽  
pp. 1-20
Author(s):  
Thomas C. Smith
Keyword(s):  
Seventeenth Century ◽  
Middle Ages ◽  
The Body ◽  
Social Classes ◽  
Vital Function ◽  
The West ◽  
Social Body ◽  
The Social ◽  
Physical Barriers ◽  
The Middle Ages

As in the Middle Ages in the West, so in Tokugawa Japan (1600–1868) men were fond of explaining the hierarchical society in which they lived by comparing it to an organism. Social classes, Confucian scholars said, were like parts of the body: each had a vital function to perform, but their functions were essentially different and unequal in value. In this scheme the peasants were second in importance only to the ruling military class. Just as the samurai officials were the brains that guided other organs, so the peasants were the feet that held the social body erect. They were the “basis of the country,” the valued producers whose labor sustained all else. But, as a class, they tended innately to backsliding and extravagance. Left alone they would consume more than their share of the social income, ape the manners and tastes of their betters, and even encroach upon the functions of other classes to the perilous neglect of their own. Only the lash of necessity and the sharp eye of the official could hold them to their disagreeable role. They had to be bound to the land; social distinctions had to be thrown up around them like so many physical barriers; and, to remove all temptation to indolence and luxury, they had to be left only enough of what they produced to let them continue producing.

Optimal wing hinge position for fast ascent in a model fly

2018 ◽  
Vol 849 ◽  
pp. 498-509
Author(s):  
R. M. Noest ◽  
Z. Jane Wang
Keyword(s):  
Stability Analysis ◽  
Body Length ◽  
Weak Dependence ◽  
The Body ◽  
Simplified Model ◽  
Centre Of Mass ◽  
Flight Stability ◽  
Hinge Position ◽  
Stroke Amplitude ◽  
Aerodynamic Lift

It was thought that the wing hinge position can be tuned to stabilize an uncontrolled fly. However here, our Floquet stability analysis shows that the hinge position has a weak dependence on the flight stability. As long as the hinge position is within the fly’s body length, both hovering and ascending flight are unstable. Instead, there is an optimal hinge position, $h^{\ast }$, at which the ascending speed is maximized. $h^{\ast }$ is approximately half way between the centre of mass and the top of the body. We show that the optimal $h^{\ast }$ is associated with the anti-resonance of the body–wing coupling, and is independent of the stroke amplitude. At $h^{\ast }$, the torque due to wing inertia nearly cancels the torque due to aerodynamic lift, minimizing the body oscillation thus maximizing the upward force. Our analysis using a simplified model of two coupled masses further predicts, $h^{\ast }=(m_{t}/2m_{w})(g/\unicode[STIX]{x1D714}^{2})$. These results suggest that the ascending speed, in addition to energetics and stability, is a trait that insects are likely to optimize.

RESEARCH OF THE INFLUENCE OF ANTIBACTERIAL AND FUNGICIDAL PREPARATIONS ON FORMATION BIOFILM OF MICROORGANISMS

2021 ◽  
Vol 1 (4) ◽  
pp. 448-458
Author(s):  
Ekaterina M. Lenchenko ◽  
◽  
Dmitriy V. Stepanov ◽  
Dmitriy A. Blumenkrants ◽  
◽  
...  
Keyword(s):  
Culture Media ◽  
Animal Husbandry ◽  
The Body ◽  
Heterogeneous Structure ◽  
Candida Spp ◽  
Functional Patterns ◽  
Frequency Occurrence ◽  
Pathological Material

The results of studies general patterns formation heterogeneous structure biofilms gram-negative and gram-positive bacteria, as well as yeast-like fungi Candida spp. are presented. Рrocesses intercellular communication of various systematic groups microorganisms has common morphological and functional patterns biofilm formation. Heteromorphic structures of biofilms united by the intercellular matrix have been revealed in natural, industrial, and clinical conditions, both in the body of mammals and birds, and in food products, devices and equipment, animal husbandry and food production technologies. Indication in a large number of microcolonies, as well as yeast and micellar phases in isolates from pathological material of animals, was a differential sign in local and systemic pathologies. Under the influence drugs on biofilms microorganisms, a direct correlation was established between morphometric and densitometric indicators, reflecting a decrease in the frequency occurrence clusters and optical density, respectively. Under the bacteriostatic effect of chemotherapeutic and disinfecting drugs, accumulations altered cells of spheroplastic type, capable forming stable and unstable L-forms, were revealed. For detection of viable microorganisms in a heterogeneous population microorganisms in vitro and in vivo, fluorescence microscopy and culture media with growth factors for the repair cell wall of L-forms bacteria are promising.

Series Active Variable Geometry Suspension Robust Control Based on Full-Vehicle Dynamics

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Cheng Cheng ◽  
Simos A. Evangelou
Keyword(s):  
High Performance ◽  
Performance Enhancement ◽  
Ride Comfort ◽  
The Body ◽  
Control Technique ◽  
Variable Geometry ◽  
Physical Constraints ◽  
Car Model ◽  
Time Domains ◽  
Vertical Accelerations

This paper demonstrates the ride comfort and road holding performance enhancement of the new road vehicle series active variable geometry suspension (SAVGS) concept using an H∞ control technique. In contrast with the previously reported work that considered simpler quarter-car models, the present work designs and evaluates control systems using full-car dynamics thereby taking into account the coupled responses from the four independently actuated corners of the vehicle. Thus, the study utilizes a nonlinear full-car model that represents accurately the dynamics and geometry of a high performance car with the new double wishbone active suspension concept. The robust H∞ control design exploits the linearized dynamics of the nonlinear model at a trim state, and it is formulated as a disturbance rejection problem that aims to reduce the body vertical accelerations and tire deflections while guaranteeing operation inside the existing physical constraints. The proposed controller is installed on the nonlinear full-car model, and its performance is examined in the frequency and time domains for various operating maneuvers, with respect to the conventional passive suspension and the previously designed SAVGS H∞ control schemes with simpler vehicle models.

scholarly journals Kinematics Measurement and Power Requirements of Fruitflies at Various Flight Speeds

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4271
Author(s):  
Hao Jie Zhu ◽  
Mao Sun
Keyword(s):  
The Body ◽  
Flight Speed ◽  
Specific Power ◽  
Flight Performance ◽  
Wingbeat Frequency ◽  
Body Angle ◽  
Flying Insects ◽  
Speed Range ◽  
Full Speed ◽  
Stroke Amplitude

Energy expenditure is a critical characteristic in evaluating the flight performance of flying insects. To investigate how the energy cost of small-sized insects varies with flight speed, we measured the detailed wing and body kinematics in the full speed range of fruitflies and computed the aerodynamic forces and power requirements of the flies. As flight speed increases, the body angle decreases and the stroke plane angle increases; the wingbeat frequency only changes slightly; the geometrical angle of attack in the middle upstroke increases; the stroke amplitude first decreases and then increases. The mechanical power of the fruitflies at all flight speeds is dominated by aerodynamic power (inertial power is very small), and the magnitude of aerodynamic power in upstroke increases significantly at high flight speeds due to the increase of the drag and the flapping velocity of the wing. The specific power (power required for flight divided by insect weigh) changes little when the advance ratio is below about 0.45 and afterwards increases sharply. That is, the specific power varies with flight speed according to a J-shaped curve, unlike those of aircrafts, birds and large-sized insects which vary with flight speed according to a U-shaped curve.

scholarly journals A Study for the Access to a Semi-synthetic Regioisomer of Natural Fucosylated Chondroitin Sulfate with Fucosyl Branches on N-acetyl-Galactosamine Units

Marine Drugs ◽  
2019 ◽  
Vol 17 (12) ◽  
pp. 655 ◽  
Author(s):  
Giulia Vessella ◽  
Serena Traboni ◽  
Anna V. A. Pirozzi ◽  
Antonio Laezza ◽  
Alfonso Iadonisi ◽  
...  
Keyword(s):  
Chondroitin Sulfate ◽  
Anticoagulant Activity ◽  
The Body ◽  
New Drugs ◽  
Coagulation Cascade ◽  
Drug Candidate ◽  
Heterogeneous Structure ◽  
Anticoagulant Drug ◽  
Chemical Strategy

Fucosylated chondroitin sulfate (fCS) is a glycosaminoglycan found up to now exclusively in the body wall of sea cucumbers. It shows several interesting activities, with the anticoagulant and antithrombotic as the most attractive ones. Its different mechanism of action on the blood coagulation cascade with respect to heparin and the retention of its activity by oral administration make fCS a very promising anticoagulant drug candidate for heparin replacement. Nonetheless, its typically heterogeneous structure, the detection of some adverse effects and the preference for new drugs not sourced from animal tissues, explain how mandatory is to open an access to safer and less heterogeneous non-natural fCS species. Here we contribute to this aim by investigating a suitable chemical strategy to obtain a regioisomer of the natural fCS polysaccharide, with sulfated l-fucosyl branches placed at position O-6 of N-acetyl-d-galactosamine (GalNAc) units instead of O-3 of d-glucuronic acid (GlcA) ones, as in natural fCSs. This strategy is based on the structural modification of a microbial sourced chondroitin polysaccharide by regioselective insertion of fucosyl branches and sulfate groups on its polymeric structure. A preliminary in vitro evaluation of the anticoagulant activity of three of such semi-synthetic fCS analogues is also reported.

scholarly journals Disc starts: the pectoral disc of stingrays promotes omnidirectional fast starts across the substrate

2019 ◽  
Vol 97 (7) ◽  
pp. 597-605 ◽  
Author(s):  
S.G. Seamone ◽  
T.M. McCaffrey ◽  
D.A. Syme
Keyword(s):  
Rigid Body ◽  
The Body ◽  
Similar Performance ◽  
Yaw Rate ◽  
Benthic Environment ◽  
Fast Start ◽  
Escape Responses ◽  
Turning Radius ◽  
Longitudinal Flexibility ◽  
Translational Speed

We explored how the flattened and rounded pectoral disc of the ocellate river stingray (Potamotrygon motoro (Müller and Henle, 1841)) enables them to use the benthic plane during fast-start escape. Escape responses were elicited via prodding different locations around the pectoral disc and were recorded using video. Modulation of pectoral-fin movements that power swimming enabled omnidirectional escape across the substrate, with similar performance in all directions of escape. Hence, translation of the body did not necessarily have to follow the orientation of the head, overcoming the constraint of a rigid body axis. An increase in prod speed was associated with an increase in initial translational speed and acceleration away from the prod. As prod location shifted towards the snout, yaw rotation increased, eventually reorienting the fish into a forward swimming position away from the prod. Furthermore, P. motoro yawed with essentially zero turning radius, allowing reorientation of the head with simultaneous rapid translation away from the prod, and yaw rate during escape was substantially greater than reported during routine swimming for stingrays. We conclude that stingrays employ a distinctive approach to escape along the substrate, which we have termed disc starts, that results in effective manoeuvrability across the benthic environment despite limited longitudinal flexibility of the body and that challenges the concept of manoeuvrability typically used for fishes.

scholarly journals De-romanticising dialogue in collaborative health care research: a critical, reflexive approach to tensions in an action research project's initial phase

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Louise Phillips ◽  
Birgitte Ravn Olesen ◽  
Michael Scheffmann-Petersen ◽  
Helle Merete Nordentoft
Keyword(s):  
Action Research ◽  
Collaborative Research ◽  
Initial Phase ◽  
Communication Theory ◽  
Complex Dynamics ◽  
Health Care Research ◽  
Research Process ◽  
The Body ◽  
Action Research Project ◽  
Ideal Types

In the current socio-political conjuncture, collaborative, dialogic forms of knowledge production abound and are idealised as democratic and inclusive. The aim of the article is to contribute to the body of critical, reflexive analyses of collaborative research by analysing how complex dynamics of exclusion as well as inclusion create tensions in researchers’ attempts to establish collaborative relations in the initial phase of an action research project. The analysis applies a framework combining Bakhtinian dialogic communication theory and Foucauldian theory to explore inclusion and exclusion in the tensional interplay of multiple voices whereby certain voices dominate. Finally, the article offers a typology of ideal types of collaborative research relations that can be used in the initial research phase as a platform for reflexive discussion between researchers and potential collaborative partners about their respective understandings of collaboration and dialogue and corresponding expectations about the research process and results.

scholarly journals A Review of Micronutrients and the Immune System–Working in Harmony to Reduce the Risk of Infection

Nutrients ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 236 ◽  
Author(s):  
Adrian F. Gombart ◽  
Adeline Pierre ◽  
Silvia Maggini
Keyword(s):  
Immune System ◽  
Immune Function ◽  
The Body ◽  
Proper Function ◽  
Risk Of Infection ◽  
Vitamin C Deficiency ◽  
Iron Copper ◽  
Physical Barriers ◽  
Different Populations ◽  
Contradictory Data

Immune support by micronutrients is historically based on vitamin C deficiency and supplementation in scurvy in early times. It has since been established that the complex, integrated immune system needs multiple specific micronutrients, including vitamins A, D, C, E, B6, and B12, folate, zinc, iron, copper, and selenium, which play vital, often synergistic roles at every stage of the immune response. Adequate amounts are essential to ensure the proper function of physical barriers and immune cells; however, daily micronutrient intakes necessary to support immune function may be higher than current recommended dietary allowances. Certain populations have inadequate dietary micronutrient intakes, and situations with increased requirements (e.g., infection, stress, and pollution) further decrease stores within the body. Several micronutrients may be deficient, and even marginal deficiency may impair immunity. Although contradictory data exist, available evidence indicates that supplementation with multiple micronutrients with immune-supporting roles may modulate immune function and reduce the risk of infection. Micronutrients with the strongest evidence for immune support are vitamins C and D and zinc. Better design of human clinical studies addressing dosage and combinations of micronutrients in different populations are required to substantiate the benefits of micronutrient supplementation against infection.

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