Trophic guilds of suction-feeding fishes are distinguished by their characteristic hydrodynamics of swimming and feeding

Suction-feeding in fishes is a ubiquitous form of prey capture whose outcome depends both on the movements of the predator and the prey, and on the dynamics of the surrounding fluid, which exerts forces on the two organisms. The inherent complexity of suction-feeding has challenged previous efforts to understand how the feeding strikes are modified when species evolve to feed on different prey types. Here, we use the concept of dynamic similarity, commonly applied to understanding the mechanisms of swimming, flying, walking and aquatic feeding. We characterize the hydrodynamic regimes pertaining to (i) the forward movement of the fish (ram), and (ii) the suction flows for feeding strikes of 71 species of acanthomorph fishes. A discriminant function analysis revealed that feeding strikes of zooplanktivores, generalists and piscivores could be distinguished based on their hydrodynamic regimes. Furthermore, a phylogenetic comparative analysis revealed that there are distinctive hydrodynamic adaptive peaks associated with zooplanktivores, generalists and piscivores. The scaling of dynamic similarity across species, body sizes and feeding guilds in fishes indicates that elementary hydrodynamic principles govern the trophic evolution of suction-feeding in fishes.

Fos regulates macrophage infiltration against surrounding tissue resistance by a cortical actin-based mechanism in Drosophila

The infiltration of immune cells into tissues underlies the establishment of tissue-resident macrophages and responses to infections and tumors. Yet the mechanisms immune cells utilize to negotiate tissue barriers in living organisms are not well understood, and a role for cortical actin has not been examined. Here, we find that the tissue invasion of Drosophila macrophages, also known as plasmatocytes or hemocytes, utilizes enhanced cortical F-actin levels stimulated by the Drosophila member of the fos proto oncogene transcription factor family (Dfos, Kayak). RNA sequencing analysis and live imaging show that Dfos enhances F-actin levels around the entire macrophage surface by increasing mRNA levels of the membrane spanning molecular scaffold tetraspanin TM4SF, and the actin cross-linking filamin Cheerio, which are themselves required for invasion. Both the filamin and the tetraspanin enhance the cortical activity of Rho1 and the formin Diaphanous and thus the assembly of cortical actin, which is a critical function since expressing a dominant active form of Diaphanous can rescue the Dfos macrophage invasion defect. In vivo imaging shows that Dfos enhances the efficiency of the initial phases of macrophage tissue entry. Genetic evidence argues that this Dfos-induced program in macrophages counteracts the constraint produced by the tension of surrounding tissues and buffers the properties of the macrophage nucleus from affecting tissue entry. We thus identify strengthening the cortical actin cytoskeleton through Dfos as a key process allowing efficient forward movement of an immune cell into surrounding tissues.

Immediate Effect of Chin Tuck Exercises on Craniovertebral Angle and Shoulder Angle Among Collegiates with Forward Head Posture

Forward head posture (FHP) is the forward movement of the head that is caused by improper postural awareness and often results in muscular imbalance that causes pain. The forward head posture is found to be influenced by Craniovertebral Angle (CV) and shoulder angle (SA) that in turn causes rounded shoulder. These biomechanical changes prove to be a hindrance in maintaining neutral head posture and affects the structural integrity. A sample size of 43 were taken according to the selection criteria and the FHP was assessed through plumb line. Double tape was used as markers at tragus of the ear, C7 vertebrae and acromion process. Photos were taken and analyzed using AUTOCAD 2017 software and the results were obtained. A positive association found between the pre and post test results for CV angle with P=0.0001(P<0.05) and no significant association between the pre and posttest for SA with P=0.2 (P>0.05). The craniovertebral angle can be altered with the chin tuck exercises but has no effect on the shoulder angle, hence having no influence over the rounded shoulders but has some effect over the forward head posture.

JOYCE's CONSTRUCTION OF INTERNAL SPEECH IN V. PELEVIN's NOVEL “THE LIFE OF INSECTS”

The article is devoted to the comparative analysis of the poetics of the novels by J. Joyce “Ulysses” and V. Pelevin “The Life of Insects”. Afore in J. Joyce's speech, speech ceases to correlate subject-object relations, turning into an independent substance, and in V. Pelevin's speech dematerialization occurs simultaneously with this process. It is important for V. Pelevin, that Joyce's techniques change the author's status, calling into question his existence as such. The article highlights general strategies for mastering someone else's word, general principles of reflection on speech models of the world, which ultimately turns into a principle of structural reassembly of universes of authors, combining both forward movement and a constant return to the origins, the desire to automate the text and the termination of any kind of dependence on reality (including thoughts and texts that are born in this universe), cyclism and movement in a circle.

Trajective Locomotion

This chapter examines the perceptual and aesthetic properties of the “follow shot,” a tracking shot that follows a human subject on foot from behind. Analyzing two films that conspicuously explore the follow shot as their core stylistic principle, Alan Clarke’s Elephant (1989) and Gus Van Sant’s Elephant (2003), this chapter shows how the formal properties of the follow shot—the camera’s forward movement, its denial of the subject’s face, and its sense of being tethered to its subject—are crucial to each film’s meditation on violence and human agency. By visually emphasizing the forward movement of its subjects while denying access to their interiorities (via the face), the follow shot attunes its viewers to its subject’s agency as a sense of pure “towardness” devoid of psychological insight, an effect the chapter calls “trajectivity.” Such a mode of representing subjectivity, the chapter argues, opposes cinematic traditions that rely on a seamless relation between psychological motivation, human expression, and human action. In doing so, the chapter offers a revised film theoretical account of the relation between camera movement, expression, and ethics.

Stability Characteristics and Mechanism of U-Shaped Metal Bellows under Symmetrical Cyclic Tension and Compression Process

The U-shaped metal bellows expansion joint compensates for the pipeline displacement by its own deformation. The compensation performance of the metal bellows in the initial stage of tension and compression deformation is unstable. In this paper, the symmetrical cyclic tension and compression (SCTC) process of metal bellows was simulated by ABAQUS software. Then, the SCTC process experiment of metal bellows was completed on the universal material testing machine. The distribution law of axial load with displacement and that of axial stiffness and yield load with cycles of metal bellows were obtained. Finally, the X-ray diffraction peak confirmed the deformation-induced martensite in the wave trough and proved that the plastic strain and hardness values of metal bellows increased with the displacement amplitude. The microstructure in the wave trough area was observed by a Zeiss microscope, and the stability characteristics mechanism of the metal bellows was revealed. The martensite in the wave trough increases the grain boundary area under SCTC loading. The forward movement of the slip band in the grain caused by large deformation reached an equilibrium state with the resistance at the grain boundary, which promotes the macroscopic mechanical properties of the metal bellows to be stable characteristics under SCTC loading.

Innovative Energy-Saving Propulsion System for Low-Speed Biomimetic Underwater Vehicles

This article covers research on an innovative propulsion system design for a Biomimetic Unmanned Underwater Vehicle (BUUV) operating at low speeds. The experiment was conducted on a laboratory test water tunnel equipped with specialised sensor equipment to assess the Fluid-Structure Interaction (FSI) and energy consumption of two different types of propulsion systems. The experimental data contrast the undulating with the drag-based propulsion system. The additional joint in the drag-based propulsion system is intended to increase thrust and decrease energy input. The tests were conducted at a variety of fins oscillation frequencies and fluid velocities. The experiments demonstrate that, in the region of low-speed forward movement, the efficiency of the propulsion system with the additional joint is greater.

Black, Proud, Silent, and Loud: Experiences of a Junior Faculty Member in 2020

Several social injustice issues, well known within the Black community, were brought to light to other ethnic/racial groups in 2020 and could no longer be ignored within the academic community. This led to personal, departmental, and institutional initiatives meant to increase racism awareness and apply change in thought and action. These initiatives often came at a cost of personal time and resources to Black and Indigenous People of Color academics, expected to contribute to these initiatives, redefine classroom syllabi, uphold research agendas, and continue with mentoring activities amidst their home environment (due to COVID-19) while monitoring their own feelings of pride, hurt, anger, anxiousness, and often- fatigue. This presentation will present the perceived triumphs and failed experiences of a junior faculty member, how they navigated this process, and explain the continued importance of institutions’ forward movement of initiatives meant to change the social and racial academic atmosphere.

Design and Dynamic Modeling of a 3-RPS Compliant Parallel Robot Driven by Voice Coil Actuators

In order to increase the driving force of the voice coil actuator while reducing its size and mass, the structural parameters of the coil and magnet in the actuator are optimized by combing Biot–Savart law with Lagrangian interpolation. A 30 mm × 30 mm × 42 mm robot based on a 3-RPS parallel mechanism driven by voice coil actuators is designed. The Lagrangian dynamic equation of the robot is established, and the mapping relationship between the driving force and the end pose is explored. The results of dynamic analysis are simulated and verified by the ADAMS software. The mapping relationship between the input current and the end pose is concluded by taking the driving force as the intermediate variable. The robot can bear a load of 10 g. The maximum axial displacement of the robot can reach 9 mm, and the maximum pitch angle and return angle can reach 40 and 35 degrees, respectively. The robot can accomplish forward movement through vibration, and the maximum average velocity can reach 4.1 mm/s.