Search

In this short note, we describe the convulsive body shuddering of a white shark as it approached two large metallic shark cages, each with multiple divers standing within them. When animals feel threatened, they experience conflicting instincts — one is to escape and another is to fight. In this situation, they do not always fight but often perform an agonistic, or aggressive display. Having arrived at the source of an olfactory corridor, this white shark was confronted with highly visible cages made with aluminium bars. The divers use hookah air hoses to breathe, and were therefore releasing bubbles, which reflect light and generate sounds as they oscillate toward the surface. The photographers may also have been taking pictures of the shark with their flash-bulb equipped cameras, which produce a sudden disruptive flash of irradiance. The shark’s behaviour is illustrated with a series of video frames as he approaches the cage. The body of the shark shutters convulsively and he opens his mouth, keeping it open for a prolonged period of 2.8 s as he passes close to the cage, while (1) depressing his pectoral fins, (2) hunching his back, (3) keeping his caudal fin held at right angle to the axis of view to increase his apparent size, and (4) shaking his body with spasmodic oscillations. The shark appears frightened, and hence may perform the display to discourage any aggression directed at him by the cage with humans emitting a panoply of frightening stimuli. Alternative explanations of the motivation behind this behaviour are also discussed. We hope that it will lead other scientists to look for this behaviour when observing the behaviour of white sharks from a cage, so they can provide further evidence shedding light upon the shark’s motivation for performing this conspicuous behaviour.

This study describes the genetic diversity and level of genetic differentiation of the scalloped hammerhead shark Sphyrna lewini from eight putative nursery areas in the Mexican Pacific Ocean, using the mtDNA control region. Genetic analyses revealed a particular spatial divergence between La Reforma and all the remaining sites, with five exclusive haplotypes and the highest genetic diversity. This pattern may be interpreted as the signature of regional female philopatry, relatively to a particular female-mediated gene flow for La Reforma, which shows a strong subdivision in the Gulf of California.

Fine‐scale movement patterns are driven by both biotic (hunting, physiological needs) and abiotic (environmental conditions) factors. The energy balance governs all movement‐related strategic decisions.Marine environments can be better understood by considering the vertical component. From 24 acoustic trackings of 10 white sharks in Guadalupe Island, this study linked, for the first time, horizontal and vertical movement data and inferred six different behavioral states along with movement states, through the use of hidden Markov models, which allowed to draw a comprehensive picture of white shark behavior.Traveling was the most frequent state of behavior for white sharks, carried out mainly at night and twilight. In contrast, area‐restricted searching was the least used, occurring primarily in daylight hours.Time of day, distance to shore, total shark length, and, to a lesser extent, tide phase affected behavioral states. Chumming activity reversed, in the short term and in a nonpermanent way, the behavioral pattern to a general diel vertical pattern., This study linked horizontal and vertical movements of white sharks from active tracking data and obtained six different behavioral states through the use of hidden Markov models.

A multi-node acoustofluidic chip working on a broadband spectrum and beyond the resonance is designed for cell manipulations. A simple one-dimensional (1D) multi-layer model is used to describe the stationary standing waves generated inside a cavity. The transmissions and reflections of the acoustic wave through the different layers and interfaces lead to the creation of pressure nodes away from the resonance condition. A transparent cavity and a broadband ultrasonic transducer allow the measurement of the acoustic energy over a wide frequency range using particle image velocimetry measurements and the relation between acoustic energy and the particles velocity. The automation of the setup allows the acquisition over a large spectrum with a high frequency definition. The results show a wide continuous operating range for the acoustofluidic chip, which compares well with the 1D model. The variation of the acoustic radiation force when varying the frequency can be compensated to ensure a constant amplitude for the ARF. This approach is finally applied to mesenchymal stem cell (MCS) spheroids cultured in acoustic levitation. The MSC spheroids can be moved and merged just by varying the acoustic frequency. This approach opens the path to various acoustic manipulations and to complex 3D tissue engineering in acoustic levitation.

Opto-acoustophoretic mobility has been demonstrated recently for fluorescent and colored particles acoustically levitated in a stationary ultrasonic field when illuminated with the appropriate optical wavelength [Dumy, Hoyos, and Aider, J. Acoust. Soc. Am. 146, 4557-4568 (2019); Zhou, Gao, Yang, Li, Shao, Zhang, Li, and Li, Adv. Sci. 5, 1800122 (2018)]. It is a repeatable phenomenon, needing both acoustic trapping and specific optic excitation to occur. However, the physical origin of the phenomenon is still debated. In this study, we provide more insights into the probable origin of this phenomenon by confronting numerical simulations with temperature controlled experiments. The phenomenon properties are well reproduced by our model, relying on a thermofluidic instability, hinting at the potential thermally induced fluid density gradient as a drag source for the observed ejection of particles. Thermostated experiments exhibit a surprising threshold above which the phenomenon is not observed anymore no matter how large the optic or acoustic energies used. This exciting observation differs from the initial interpretation of the phenomenon, altering its potential application without removing its interest because it suggests the possible contactless generation of customized flows by acoustically trapped particles.

International audience; The twilight zone contains the largest biomass of the world's ocean. Identifying its role in the trophic supply and contaminant exposure of marine megafauna constitutes a critical challenge in the context of global change. The white shark (Carcharodon carcharias) is a threatened species with some of the highest concentrations of neurotoxin methylmercury (MeHg) among marine top predators. Large white sharks migrate seasonally from coastal habitats, where they primarily forage on pinnipeds, to oceanic offshore habitats. Tagging studies suggest that while offshore, white sharks may forage at depth on mesopelagic species, yet no biochemical evidence exists. Here, we used mercury isotopic composition to assess the dietary origin of MeHg contamination in white sharks from the Northeast Pacific Ocean. We estimated that a minimum of 72% of the MeHg accumulated by white sharks originates from the consumption of mesopelagic prey, while a maximum of 25% derives from pinnipeds. In addition to highlighting the potential of mercury isotopes to decipher the complex ecological cycle of marine predators, our study provides evidence that the twilight zone constitutes a crucial foraging habitat for these large predators, which had been suspected for over a decade. Climate change is predicted to expand the production of mesopelagic MeHg and modify the mesopelagic biomass globally. Considering the pivotal role of the twilight zone is therefore essential to better predict both MeHg exposure and trophic supply to white sharks, and effectively protect these key vulnerable predators.

Carcharodon carcharias is a protected species occupying the apex of most marine foodwebs where they are present. Aggregation areas, such as Guadalupe Island, México, that have been related to feeding events, are of special interest for this species conservation. The aim of this study was to describe the fatty acid profile of C. carcharias' muscle for the first time on Guadalupe Island, using non-lethal biopsy methods to determine ontogenetic and sex differences in relation to diet and habitat use. Fatty acid profiles and biomarkers from different individuals are explored as a source of integrated information of their diet. Analysis of the fatty acid composition of individuals with varying total lengths (2.3-5.0 m) suggested a dietary shift between juveniles and adults occurring at aproximately 3 m. Fatty acid biomarkers indicated a higher degree of carnivorism in adults than in juveniles. Additionally, these ecological tracers suggested that juveniles feed in shallow waters close to the coast, while adults feed in deep waters along inshore and offshore areas. This study represents a first step towards using fatty acid composition as a relevant tool for further understanding dietary shifts and habitat use throughout the ontogeny of C. carcharias. However, to corroborate this, further studies with larger sample sizes are required.

A raíz de las recientes excavaciones realizadas en la que fuera la Calle Real de Santafé de Bogotá (Colombia), se pusieron en evidencia distintos sistemas de cañe- rías de aguas consumibles y residuales. Estos hallazgos condujeron a la realización de los análisis tipológico y arqueométrico de las distintas estructuras excavadas, los cuales permitieron identificar sus funciones y periodos de construcción. Con base en estos análisis, también fue posible hacer un seguimiento de la tradición artesanal de la cual se desprenden estas estructuras hidráulicas, las que en su totalidad son manufacturadas con elementos cerámicos. Así mismo, se profundizó en la docu- mentación histórica, particularmente para la época republicana, desde la cual se hicieron evidentes diferentes procesos sociales y culturales. Por último, a partir de un análisis más amplio, se plantean hipótesis alternativas sobre la selección del lugar de fundación y la orientación de la traza de la ciudad.

Large marine predators exhibit high concentrations of mercury (Hg) as neurotoxic methylmercury, and the potential impacts of global change on Hg contamination in these species remain highly debated. Current contaminant model predictions do not account for intraspecific variability in Hg exposure and may fail to reflect the diversity of future Hg levels among conspecific populations or individuals, especially for top predators displaying a wide range of ecological traits. Here, we used Hg isotopic compositions to show that Hg exposure sources varied significantly between and within three populations of white sharks (Carcharodon carcharias) with contrasting ecology: the north-eastern Pacific, eastern Australasian, and south-western Australasian populations. Through Δ200Hg signatures in shark tissues, we found that atmospheric Hg deposition pathways to the marine environment differed between coastal and offshore habitats. Discrepancies in δ202Hg and Δ199Hg signatures among white sharks provided evidence for intraspecific exposure to distinct sources of marine methylmercury, attributed to population and ontogenetic shifts in foraging habitat and prey composition. We finally observed a strong divergence in Hg accumulation rates between populations, leading to three times higher Hg concentrations in large Australasian sharks compared to north-eastern Pacific sharks, and likely due to different trophic strategies adopted by adult sharks across populations. This study illustrates the variety of Hg exposure sources and bioaccumulation patterns that can be found within a single species and suggests that intraspecific variability needs to be considered when assessing future trajectories of Hg levels in marine predators.

This study constitutes the first descriptions of morphological abnormalities in the silky shark Carcharhinus falciformis from a near term embryo obtained in the Gulf of California, Mexico. External exploration and X-ray images were taken to describe the specimen, which revealed that the embryos deformities were located in the cephalic region suggesting a holoprosencephaly disorder. The analyzed images evidenced a deformed oval chondrocranium with both nasal capsules pointing upwards and the rostrum pointing downwards, in which the palatoquadrate cartilage was deformed with signs of prognathism.

REPLYING TO H. Murua et al. Nature https://doi.org/10.1038/s41586-021-03396-4 (2021) Our previously published paper1 provided global fine-scale spatiotemporal estimates (1° × 1°; monthly) of overlap and fishing exposure risk (FEI) between satellite-tracked shark space use and automatic identification system (AIS) longline fishing effort. We did not assess shark mortality directly, but in addition to replying to the Comment by Murua et al.2, we confirm—using regression analysis of spatially matched data—that fishing-induced pelagic shark mortality (catch per unit effort (CPUE)) is greater where FEI is higher. We focused on assessing shark horizontal spatiotemporal overlap and exposure risk with fisheries because spatial overlap is a major driver of fishing capture susceptibility and previous shark ecological risk assessments (ERAs) assumed a homogenous shark density within species-range distributions3,4,5 or used coarse-scale modelled occurrence data, rather than more ecologically realistic risk estimates in heterogeneous habitats that were selected by sharks over time. Furthermore, our shark spatial exposure risk implicitly accounts for other susceptibility factors with equal or similar probabilities to those commonly used in shark ERAs3,5.

In recent years, 3D cell culture models such as spheroid or organoid technologies have known important developments. Many studies have shown that 3D cultures exhibit better biomimetic properties compared to 2D cultures. These properties are important for in-vitro modeling systems, as well as for in-vivo cell therapies and tissue engineering approaches. A reliable use of 3D cellular models still requires standardized protocols with well-controlled and reproducible parameters. To address this challenge, a robust and scaffold-free approach is proposed, which relies on multi-trap acoustic levitation. This technology is successfully applied to Mesenchymal Stem Cells (MSCs) maintained in acoustic levitation over a 24-h period. During the culture, MSCs spontaneously self-organized from cell sheets to cell spheroids with a characteristic time of about 10 h. Each acoustofluidic chip could contain up to 30 spheroids in acoustic levitation and four chips could be ran in parallel, leading to the production of 120 spheroids per experiment. Various biological characterizations showed that the cells inside the spheroids were viable, maintained the expression of their cell surface markers and had a higher differentiation capacity compared to standard 2D culture conditions. These results open the path to long-time cell culture in acoustic levitation of cell sheets or spheroids for any type of cells.

International audience; In recent years, 3D cell culture models such as spheroid or organoid technologies have known important developments. Many studies have shown that 3D cultures exhibit better biomimetic properties compared to 2D cultures. These properties are important for in-vitro modeling systems, as well as for in-vivo cell therapies and tissue engineering approaches. A reliable use of 3D cellular models still requires standardized protocols with well-controlled and reproducible parameters. To address this challenge, a robust and scaffold-free approach is proposed, which relies on multi-trap acoustic levitation. This technology is successfully applied to Mesenchymal Stromal Cells (MSCs) maintained in acoustic levitation over a 24-hour period. During the culture, MSCs spontaneously self-organized from cell sheets to cell spheroids with a characteristic time of about ten hours. Each acoustofluidic chip could contain up to 30 spheroids in acoustic levitation and four chips could be ran in parallel, leading to the production of 120 spheroids per experiment. Various biological characterizations showed that the cells inside the spheroids were viable, maintained the expression of their cell surface markers and had a higher differentiation capacity compared to standard 2D culture conditions. These results open the path to long-time cell culture in acoustic levitation of cell sheets or spheroids for any type of cells.; In recent years, 3D cell culture models such as spheroid or organoid technologies have known important developments. Many studies have shown that 3D cultures exhibit better biomimetic properties compared to 2D cultures. These properties are important for in-vitro modeling systems, as well as for in-vivo cell therapies and tissue engineering approaches. A reliable use of 3D cellular models still requires standardized protocols with well-controlled and reproducible parameters. To address this challenge, a robust and scaffold-free approach is proposed, which relies on multi-trap acoustic levitation. This technology is successfully applied to Mesenchymal Stromal Cells (MSCs) maintained in acoustic levitation over a 24-hour period. During the culture, MSCs spontaneously self-organized from cell sheets to cell spheroids with a characteristic time of about ten hours. Each acoustofluidic chip could contain up to 30 spheroids in acoustic levitation and four chips could be ran in parallel, leading to the production of 120 spheroids per experiment. Various biological characterizations showed that the cells inside the spheroids were viable, maintained the expression of their cell surface markers and had a higher differentiation capacity compared to standard 2D culture conditions. These results open the path to long-time cell culture in acoustic levitation of cell sheets or spheroids for any type of cells.

Esta ponencia, presentada a manera de artículo de reflexión, invita a todos los miembros de las comunidades educativas a reflexionar sobre la formación docente y lo que la constituye –la práctica y el saber pedagógicos–, y a repensar dicha formación como un factor incidente en la calidad de la educación en Colombia. Adicionalmente, plantea la necesidad de definir los parámetros con los cuales debe entenderse, analizarse y evaluarse la calidad de la educación, para que esta se traduzca en ese “anhelado ideal” que representa para el tipo de sociedad que se quiere construir. Por último, se presenta la contradicción entre lo que se les ofrece a los profesores en sus procesos formativos y lo que se les exige, seguida de una serie de digresiones acerca de la formación del profesorado y la inversión que se hace en ella.

Split-flow fractionation (SPLITT) is a family of techniques that separates in the absence of labeling using very low flow rates and force fields, and is therefore expected to minimize cell damage. Although it has been documented that separation methods cause physiological changes in immune cells that are attributable to mechanical stress and antibody labeling, SPLITT has not yet been examined for possible damaging effects of hydrodynamic stress, partly because it is assumed that the low flow rates and weak forces used in this technique do not generate significant mechanical stress. The aim of this study was to investigate the effects of SPLITT on cell function of a murine macrophage cell, and to compare these effects with those induced by centrifugation. Macrophages J774.2 were cultured in RPMI-enriched media, then detached from the culture flask and resuspended for 12 h. Cell suspensions were diluted in a buffered saline solution and exposed to SPLITT (flow rates 1–10 ml/min) or centrifugation (100–1500g) for 10 min. Cell viability, diameter, membrane potential, and nitric oxide production were measured. Under the operating conditions employed, cell viability was above 98% after SPLITT and centrifugation but cells suffered immediate hydrodynamic cell damage, including decreased cell diameter and membrane hyperpolarization which was inhibitable by 4-aminopyridine; nitric oxide production was not affected. Pressure values during SPLITT and centrifugation correlated with diameter and membrane potential. Our data do not support the assumption that SPLITT is innocuous to cell function. Some changes in SPLITT channel design are suggested to minimize cell damage. Membrane potential and cell diameter are sensitive indicators for the evaluation of sublethal damage in different cell models, and allow identification of optimal operating conditions on different scales. © 2019 Elsevier B.V.

We present an approach based on acoustic levitation to grow the cells without wall interactions in order to promote 3D cell architecture (spheroïd, organoïd). The 3D microenvironment is indeed closer to In Vivo physiological behavior. The suspended cells are moved toward the acoustic pressure nodes where they are trapped and maintained in acoustic levitation in perfectly straight monolayers reaching very quickly the classical confluency of the cells in 2D culture. Interestingly, by maintaining the monolayers of MSCs in culture over a 24-h period, the MSCs spontaneously self-organized from cell sheets to cell spheroids with a characteristic time of about 10 h. This approach of 3D cell culture is based on the use of the acoustic wave coupled with microfluidics. We designed a standing wave cavity to generate a large acoustic radiation force (ARF) with an optical access, which allows the characterization of the self-organization dynamics. This 3D cell culture method has been validated on MSCs over 24h experiments. The MSCs viability has been checked. Moreover, they show a higher differentiation capacity compared to standard 2D culture conditions. These results open the path to long-time cell culture in acoustic levitation of cell sheets or spheroids for any type of cells.

The classic approaches to generate the Acoustic Radiation Force (ARF) in a standing wave cavity are based on the use of a specific height for the cavity and a narrow-band acoustic frequency to reach the resonance. We present a robust multi-node cavity working over a broadband range of frequency. This approach allows large acoustophoresis manipulations. The design of a transparent cavity and the use of a broadband ultrasonic transducer allowed the characterization of the acoustic energy and the comparison with a simple 1-D model. The acoustic properties of the system were estimated through the effects of the acoustic radiation forces on particles suspension. From the particle velocities induced by the ARF, measured with a Particle Image Velocimetry (PIV) approach, we deduced the acoustic energy over a large frequency range. The automation of the setup allowed the acquisition of a large amount of data to make parametric studies. The results show a wide continuous operating range for the acoustic radiation forces. Furthermore, the occurrence of the resonance peaks allows an increase by a factor ten of the force magnitude. This broadband effect also enables an accurate control of the node positions by tuning the proper acoustic frequency.

REPLYING TO A. V. Harry & J. M. Braccini Nature https://doi.org/10.1038/s41586-021-03463-w (2021) Our global analysis1 estimated the overlap and fishing exposure risk (FEI) using the space use of satellite-tracked sharks and longline fishing effort monitored by the automatic identification system (AIS). In the accompanying Comment, Harry and Braccini2 draw attention to two localized shark–longline vessel overlap hotspots in Australian waters, stating that 47 fishing vessels were misclassified as longline and purse seine vessels in the Global Fishing Watch (GFW)3 2012–2016 AIS fishing effort data product that we used. This, they propose2, results in misidentifications that highlight fishing exposure hotspots that are subject to an unexpected level of sensitivity in the analysis and they suggest that misidentifications could broadly affect the calculations of fishing exposure and the central conclusions of our study1. We acknowledged in our previously published paper1 that gear reclassifications were likely to occur for a small percentage of the more than 70,000 vessels studied, however, here we demonstrate that even using much larger numbers of vessel reclassifications than those proposed by Harry and Braccini2, the central results and conclusions of our paper1 do not change.

Because the absence of sedimentation in zero-gravity makes the culture and the manipulation of cells or particles challenging, an attractive alternative is to use the Acoustic Radiation Force (ARF) as an artificial “acoustic gravity.” To evaluate the potential of this approach we studied the behavior of dense gold nanorods under ARF during a parabolic flight campaign. Using dense objects enhances the effect of gravity on the axial position of the so-called “levitation plane,” which is the equilibrium position at which ARF balances gravity in the laboratory. Further, using elongated objects, instead of spherical particles provides information about their spatial orientations in addition to their propulsion observed in standard gravity conditions. Our experiments clearly show a different collective organization and individual behavior of the rods in micro-gravity conditions. First, the axial location of the levitation plane is different in microgravity than in hypergravity: it matches the nodal pressure plane in microgravity while it is much lower than the nodal plane in hypergravity. Our experiments also show a sharp transition from horizontal to axial orientation of the rods axis. The propulsion of the rods also stops when transitioning to micro-gravity. A possible explanation for the sudden change of orientation and stopping of propulsion is the modification of the equilibrium between the axial and transverse components of the ARF. While these experiments show that some phenomena, like the propulsion of nanorods by ARF, may not be applicable in microgravity, they do confirm that acoustic manipulation of particles or cells in microgravity is possible, which paves for the development of many useful techniques for particles or cells manipulation, like cell cultures, during long-term space travel.

Marine animal tracking has become one of the major tools used to understand the behavior and ecology of a multitude of species in the ocean, thus there is an increasing body of knowledge about this subject worldwide, particularly for sharks. Nevertheless, little was known of the movement patterns of shark in the Mexican Pacific (MXP) and Gulf of California (GOC), except for the pioneering work carried out in the 1980s on the movements of scalloped hammerhead sharks in El Bajo Espiritu Santo and other islands in the region, as well as ongoing studies on white shark movements, migratory patterns and behavior off Isla Guadalupe. Here we present an overview of previous studies on the movements of sharks, as well as a comprehensive description of new studies currently being carried out by our research group at Pelagios Kakunjá on several species of sharks in the MXP. We show how information gleaned from these studies can be put to use to guide sustainable exploitation policies and promote effective conservation practices.

White sharks (Carcharodon carcharias) are described as generalist predators, with a demonstrated ontogenetic dietary shift which occurs between subadult and adult life stages. Trophic ecology studies on white shark have been focused mainly on large and mature individuals, necessitating studies of young white shark trophic ecology to better understand their resource use. This study provides new insights into young white shark diet in the North eastern Pacific Ocean using stable isotope analysis in muscle tissues. We analyzed δ13C and δ15N values of young white shark muscle (n = 21) from Sebastian Vizcaino Bay (SBV) during 2015–2018. We found changes in prey composition across early [neonates, young-of-the-years (YOYs), juveniles] white shark life stages, with significant changes in isotopic composition throughout early ontogeny. Mixing model results indicate a high use of coastal areas for foraging, mainly for juvenile stages and the substantial contribution of pelagic preys (e.g., S. japonicus, Prionotus spp., Cynoscion spp., S. sagax, etc.) in YOYs, white shark diet also indicates an important role of offshore foraging. This change in isotopic composition likely represents the shift from the embryo’s typical maternally derived isotopic signature, incorporated in offshore foraging regions, to the postpartum isotopic composition incorporated by foraging neonates in inshore nursery habitats. This study provides relevant information regarding young white shark feeding preferences, reinforces the importance of coastal areas as critical habitat for the development and the successful foraging of this species, and also provides indirect insights on the feeding habits of the adult female of white sharks, which constitutes a baseline for further research.

Acoustic Radiation Force is commonly used to create stable large-scale aggregates of particles in levitation (so-called “acoustic levitation”) in a micro-cavity. The authors show in the following work that this well-known and well-controlled aggregation process can be reversed without contact or external flow if the aggregated particles are enlightened with the proper optical wavelength. This coupled optics and acoustics effect has been observed with various kinds of particles and different optic wavelengths, showing high reproducibility. The phenomenon is studied using fluorescent micro-metric polystyrene particles without flow, and the effects of acoustic energy and illumination power have been quantitatively assessed. It is then exploited to separate a mix of particles with identical mechanical properties based on their different optic absorption. If the phenomenon is not well understood, some possible mechanisms are proposed and discussed that could be responsible for the rapid ejection of the objects in levitation from the illuminated area. Since it is a tag free phenomenon that does not need high energies to happen and since it works with biological objects such as algae, red blood cells, and bacteria, it may open the way to a broad range of applications.

Marine animal tracking has become one of the major tools used to understand the behavior and ecology of a multitude of species in the ocean, thus there is an increasing body of knowledge about this subject worldwide, particularly for sharks. Nevertheless, little was known of the movement patterns of shark in the Mexican Pacific (MXP) and Gulf of California (GOC), except for the pioneering work carried out in the 1980s on the movements of scalloped hammerhead sharks in El Bajo Espiritu Santo and other islands in the region, as well as ongoing studies on white shark movements, migratory patterns and behavior off Isla Guadalupe. Here we present an overview of previous studies on the movements of sharks, as well as a comprehensive description of new studies currently being carried out by our research group at Pelagios Kakunja on several species of sharks in the MXP. We show how information gleaned from these studies can be put to use to guide sustainable exploitation policies and promote effective conservation practices.

We theoretically investigate how the acoustic radiation force and torque arise on a small spheroidal particle immersed in a nonviscous fluid inside an ideal cylindrical chamber. The ideal chamber comprises a hard top and bottom (rigid boundary condition), and a soft or hard lateral wall. By assuming the particle is much smaller than the acoustic wavelength, we present analytical expressions of the radiation force and torque caused by an acoustic wave of arbitrary shape. Unlike previous results, these expressions are given relative to a fixed laboratory frame. Our model is showcased for analyzing the behavior of an elongated metallic microspheroid (with a 10 : 1 aspect ratio) in a half-wavelength acoustofluidic chamber with a few millimeters diameter. The results show the radiation torque aligns the microspheroid along the nodal plane, and the radiation force causes a translational motion with a speed of up to one body length per second. At last, we discuss the implications of this study to propelled nanorods by ultrasound., Comment: 11 pages, 3 figures