Outer Body Research Articles

Lagrange versus Lyapunov Stability of Hierarchical Triple Systems: Dependence on the Mutual Inclination between Inner and Outer Orbits

While there have been many studies examining the stability of hierarchical triple systems, the meaning of “stability” is somewhat vague and has been interpreted differently in previous literatures. The present paper focuses on “Lagrange stability,” which roughly refers to the stability against the escape of a body from the system, or “disruption” of the triple system, in contrast to “Lyapunov-like stability,” which is related to the chaotic nature of the system dynamics. We compute the evolution of triple systems using direct N-body simulations up to 107 P out, which is significantly longer than previous studies (with P out being the initial orbital period of the outer body). We obtain the resulting disruption timescale T d as a function of the triple orbital parameters with particular attention to the dependence on the mutual inclination between the inner and outer orbits, i mut. By doing so, we have clarified explicitly the difference between Lagrange and Lyapunov stabilities in astronomical triples. Furthermore, we find that the von Zeipel–Kozai–Lidov oscillations significantly destabilize inclined triples (roughly with 60° < i mut < 150°) relative to those with i mut = 0°. On the other hand, retrograde triples with i mut > 160° become strongly stabilized with much longer disruption timescales. We show the sensitivity of the normalized disruption timescale T d/P out to the orbital parameters of triple system. The resulting T d/P out distribution is practically more useful in a broad range of astronomical applications than the stability criterion based on the Lyapunov divergence.

Variably Premixed Rotating Detonation Engine for Evaluation of Detonation Cycle Dynamics

A variably premixed rotating detonation engine using gaseous hydrogen and air reactants is introduced to enable investigation of key cycle processes while varying the homogeneity of the reactant inlet conditions. Two chamber configurations are investigated, the first with reactants filling the entire span of a straight annular channel and the second with a slightly larger channel and a backward-facing step. The first configuration permits both premixed and non-premixed fuel injection, enabling mixing quality modulation. The second configuration is operated only at fully premixed conditions. Operating modes and detonation wave speeds are characterized using exhaust-plume imaging, while the chamber heat release field is captured by transverse imaging through a transparent outer body. Tests using the first configuration were characterized by unstable counterpropagating modes with low detonation wave speeds regardless of the state of premixing, while the second configuration rendered single-wave behavior with wave speeds up to 86% of the Chapman–Jouguet velocity. Comparisons with a simple computational fluid dynamics model of the second configuration indicate that reactant preheating significantly influences the detonation wave topology, highlighting the potential utility of the test platform for isolating key physics associated with the effects of reactant premixing, preheating, and chamber geometry on rotating detonation engine operation.

Sense of self in mind and body: an eLORETA-EEG study.

The human brain engages the sense of self through both semantic and somatic self-referential processing (SRP). Alpha and theta oscillations have been found to underlie SRP but have not been compared with respect to semantic and somatic SRP. We recorded electroencephalography (EEG) from 50 participants during focused internal attention on life roles (e.g. "friend") and outer body (e.g. "arms") compared to resting state and an external attention memory task and localized the sources of on-scalp alpha (8-12 Hz) and theta (4-8 Hz) EEG signals with exact low-resolution tomography. Logarithm of F-ratios was calculated to compare differences in alpha and theta power between SRP conditions, resting state, and external attention. Results indicated that compared to resting state, semantic SRP induced lower theta in the frontal cortex and higher theta in the parietal cortex, whereas somatic SRP induced lower alpha in the frontal and insula cortex and higher alpha in the parietal cortex. Furthermore, results indicated that compared to external attention, both semantic and somatic SRP induced higher alpha in the dorsolateral prefrontal cortex with lateralized patterns based on task condition. Finally, an analysis directly comparing semantic and somatic SRP indicated frontal-parietal and left-right lateralization of SRP in the brain. Our results suggest the alpha and theta oscillations in the frontal, parietal, and the insula cortex may play crucial roles in semantic and somatic SRP.

Will plain packaging of cigarettes achieve the expected? Perceptions among medical students

Plain packaging is one of the critical strategies in eliminating the promotion of tobacco products. Evidence indicates that plain packaging decreases the attractiveness of tobacco products and enhances the effectiveness of health warnings. This study aimed to explore the perceptions of undergraduate medical students of plain packaging and new pictorial warnings before they came into use in Turkey. This qualitative study was carried out among undergraduate students in a Medical School in Istanbul in 2019. Participants were recruited through purposive sampling, and data were collected through focus group discussions. The participants were asked to discuss their perceptions regarding one original branded pack and ten plain package models. All discussions were audiotaped and thematic content analysis was conducted. A total of 72 students participated in the study. None of the students had seen plain packaging before. Most of the students perceived plain packaging as more favorable compared to the branded packs. The terms used to describe plain package were: 'appealing/desirable', 'attractive', 'beautiful', 'cool/eye-catching', 'charming', 'elegant', and 'special'. Some students indicated that they would have preferred plain packs over the branded ones if both types of products had been in the market and provided they were of the same brand. Pictorials had different impacts based on their content. At the same time, outer body deformities were perceived as 'real' and provoked unfavorable feelings; inner organ images were defined as 'imaginary' and had little to no impact. Plain packaging was perceived as a more attractive alternative to the conventional branded packs among most participants. We must be aware of the unforeseen effects of plain packaging among different subgroups in the new generations. We suggest using outer body deformities in the pictorials more frequently due to their higher impact.

Dynamical perturbations around an extreme mass ratio inspiral near resonance

Extreme mass ratio inspirals (EMRIs) -- systems with a compact object orbiting a much more massive (e.g., galactic center) black hole -- are of interest both as a new probe of the environments of galactic nuclei, and their waveforms are a precision test of the Kerr metric. This work focuses on the effects of an external perturbation due to a third body around an EMRI system. This perturbation will affect the orbit most significantly when the inner body crosses a resonance with the outer body, and result in a change of the conserved quantities (energy, angular momentum, and Carter constant) or equivalently of the actions, which results in a subsequent phase shift of the waveform that builds up over time. We present a general method for calculating the changes in action during a resonance crossing, valid for generic orbits in the Kerr spacetime. We show that these changes are related to the gravitational waveforms emitted by the two bodies (quantified by the amplitudes of the Weyl scalar $\psi_4$ at the horizon and at $\infty$) at the frequency corresponding to the resonance. This allows us to compute changes in the action variables for each body, without directly computing the explicit metric perturbations, and therefore we can carry out the computation by calling an existing black hole perturbation theory code. We show that our calculation can probe resonant interactions in both the static and dynamical limit. We plan to use this technique for future investigations of third-body effects in EMRIs and their potential impact on waveforms for LISA.

On the Embodiment of Social Cognition Skills: The Inner and Outer Body Processing Differently Contributes to the Affective and Cognitive Theory of Mind.

A specific interpretation of embodiment assigns a central role to the body representations (BR) in cognition. In the social cognition domain, BR could be pivotal in representing others' actions and states. However, empirical evidence on the relationship between different BR and social cognition, in terms of Theory of Mind (ToM), in the same sample of participants is missing. Here, this relationship was explored considering individual differences in the action-oriented BR (aBR), nonaction-oriented BR (NaBR), and subjective predisposition toward internal bodily sensations (interoceptive sensibility, ISe). Eighty-two healthy adults were given behavioral measures probing aBR, NaBR, ISe, and affective/cognitive ToM. The results suggest that NaBR, which mainly relies on exteroceptive signals, predicts individual differences in cognitive ToM, possibly because it can allow differentiating between the self and others. Instead, the negative association between affective ToM and ISe suggests that an alteration of the internal body state representation (i.e., over-reporting interoceptive sensations) can affect emotional processing in social contexts. The finding that distinct aspects of the body processing from within (ISe) and from the outside (NaBR) differently contribute to ToM provides empirical support to the BR role in social cognition and can be relevant for developing interventions in clinical settings.

Nature-Inspired Design and Advanced Multi-Computational Investigations on the Mission Profile of a Highly Manoeuvrable Unmanned Amphibious Vehicle for Ravage Removals in Various Oceanic Environments

Recent large-scale operations, including frequent maritime transportation and unauthorised as well as unlawful collisions of drainage wastes, have polluted the ocean’s ecology. Due to the ocean’s unsuitable ecology, the entire globe may experience drastic aberrant conditions, which will force illness onto all living things. Therefore, an advanced system is very necessary to remove the undesired waste from the ocean’s surface and interior. Through the use of progressive unmanned amphibious vehicles (UAV), this study provides a dynamic operational mode-based solution to damage removal. In order to successfully handle the heavy payloads of ravage collections when the UAV reveals centre of gravity concerns, a highly manoeuvrable-based design inspired by nature has been imposed. The ideal creatures to serve as the inspiration for this piece are tropical birds, which have a long tail for navigating tricky situations. The design initialization was carried out by focusing on the outer body of tropical birds. Following this, special calculations were conducted and the full design parameters of the UAV were established. This study proposes a unique mathematical formulation for the development of primary and secondary design parameters of an UAV. The proposed mission profile of this application is computationally tested with the aid of sophisticated computational methodologies after the modelling of this UAV. The computational methods that are required are one-way coupling-based hydro-structural interaction assessments and computational hydrodynamic analyses. Computing is used to determine the aerodynamic and hydrodynamic forces over the UAV, the lightweight materials to withstand high fluid dynamic loads, and the buoyancy forces to complete the UAV components. These computational methods have been used to produce a flexible and fine-tuned UAV design for targeted real-time applications.

High-resolution ALMA and HST imaging of κCrB: a broad debris disc around a post-main-sequence star with low-mass companions

ABSTRACT $\kappa \,$ CrB is an ∼2.5 Gyr old K1 sub-giant star, with an eccentric exo-Jupiter at ∼2.8 au and a debris disc at tens of au. We present ALMA (Atacama Large Millimetre/submillimetre Array) Band 6 (1.3 mm) and Hubble Space Telescope scattered light (0.6$\, \mu$m) images, demonstrating $\kappa \,$CrB’s broad debris disc, covering an extent $50\!-\!180\,$au in the millimetre (peaking at 110 au), and $51\!-\!280\,$au in scattered light (peaking at 73 au). By modelling the millimetre emission, we estimate the dust mass as ${\sim }0.016\, {\rm M}_\oplus$, and constrain lower-limit planetesimal sizes as $D_{\rm {max}}{\gtrsim }1\,$km and the planetesimal belt mass as $M_{\rm {disc}}{\gtrsim }1\, {\rm M}_\oplus$. We constrain the properties of an outer body causing a linear trend in 17 yr of radial velocity data to have a semimajor axis 8–66 au and a mass $0.4\!-\!120\, M_{\rm {Jup}}$. There is a large inner cavity seen in the millimetre emission, which we show is consistent with carving by such an outer massive companion with a string of lower mass planets. Our scattered light modelling shows that the dust must have a high anisotropic scattering factor (g ∼ 0.8–0.9) but an inclination (i ∼ 30°–40°) that is inferred to be significantly lower than the i ∼ 61° millimetre inclination. The origin of such a discrepancy is unclear, but could be caused by a misalignment in the micrometre- and millimetre-sized dust. We place an upper limit on the CO gas mass of $M_{\rm {CO}}{\lt }(4.2\!-\!13) \times 10^{-7}\, {\rm M}_\oplus$, and show this to be consistent with levels expected from planetesimal collisions, or from CO-ice sublimation as $\kappa \,$CrB begins its giant branch ascent.

Deiters Cells Act as Mechanical Equalizers for Outer Hair Cells.

The outer hair cells in the mammalian cochlea are cellular actuators essential for sensitive hearing. The geometry and stiffness of the structural scaffold surrounding the outer hair cells will determine how the active cells shape mammalian hearing by modulating the organ of Corti (OoC) vibrations. Specifically, the tectorial membrane and the Deiters cell are mechanically in series with the hair bundle and soma, respectively, of the outer hair cell. Their mechanical properties and anatomic arrangement must determine the relative motion among different OoC structures. We measured the OoC mechanics in the cochleas acutely excised from young gerbils of both sexes at a resolution fine enough to distinguish the displacement of individual cells. A three-dimensional finite element model of fully deformable OoC was exploited to analyze the measured data in detail. As a means to verify the computer model, the basilar membrane deformations because of static and dynamic stimulations were measured and simulated. Two stiffness ratios have been identified that are critical to understand cochlear physics, which are the stiffness of the tectorial membrane with respect to the hair bundle and the stiffness of the Deiters cell with respect to the outer hair cell body. Our measurements suggest that the Deiters cells act like a mechanical equalizer so that the outer hair cells are constrained neither too rigidly nor too weakly.SIGNIFICANCE STATEMENT Mammals can detect faint sounds thanks to the action of mammalian-specific receptor cells called the outer hair cells. It is getting clearer that understanding the interactions between the outer hair cells and their surrounding structures such as the tectorial membrane and the Deiters cell is critical to resolve standing debates. Depending on theories, the stiffness of those two structures ranges from negligible to rigid. Because of their perceived importance, their properties have been measured in previous studies. However, nearly all existing data were obtained ex situ (after they were detached from the outer hair cells), which obscures their interaction with the outer hair cells. We quantified the mechanical properties of the tectorial membrane and the Deiters cell in situ.

Tilting Uranus via Spin–Orbit Resonance with Planet Nine

Uranus’s startlingly large obliquity of 98° has yet to admit a satisfactory explanation. The most widely accepted hypothesis involving a giant impactor that tipped Uranus onto its side encounters several difficulties with regard to Uranus’s spin rate and prograde satellite system. An obliquity increase that was driven by capture of Uranus into a secular spin–orbit resonance remains a possible alternative hypothesis that avoids many of the issues associated with a giant impact. We propose that secular spin–orbit resonance could have excited Uranus’s obliquity to its present-day value if it was driven by the outward migration of an as-yet-undetected outer solar system body commonly known as Planet Nine. We draw support for our hypothesis from an analysis of 123 N-body simulations with varying parameters for Planet Nine and its migration. We find that in multiple instances, a simulated Planet Nine drives Uranus’s obliquity past 98°, with a significant number falling within 10% of this value. We note a significant caveat to our results in that a much faster than present-day spin axis precession rate for Uranus is required in all cases for it to reach high obliquities. We conclude that while it was, in principle, possible for Planet Nine (if it exists) to have been responsible for Uranus’s obliquity, the feasibility of such a result hinges on Uranus’s primordial precession rate.

Systematic Review and Meta-Analysis of Normal Infrarenal Aortic Diameter in the General Worldwide Population and Changes in Recent Decades

Systematic Review and Meta-Analysis of Normal Infrarenal Aortic Diameter in the General Worldwide Population and Changes in Recent Decades

Toward a Holistic Communication Approach to an Automated Vehicle's Communication With Pedestrians: Combining Vehicle Kinematics With External Human-Machine Interfaces for Differently Sized Automated Vehicles.

Future automated vehicles (AVs) of different sizes will share the same space with other road users, e. g., pedestrians. For a safe interaction, successful communication needs to be ensured, in particular, with vulnerable road users, such as pedestrians. Two possible communication means exist for AVs: vehicle kinematics for implicit communication and external human-machine interfaces (eHMIs) for explicit communication. However, the exact interplay is not sufficiently studied yet for pedestrians' interactions with AVs. Additionally, very few other studies focused on the interplay of vehicle kinematics and eHMI for pedestrians' interaction with differently sized AVs, although the precise coordination is decisive to support the communication with pedestrians. Therefore, this study focused on how the interplay of vehicle kinematics and eHMI affects pedestrians' willingness to cross, trust and perceived safety for the interaction with two differently sized AVs (smaller AV vs. larger AV). In this experimental online study (N = 149), the participants interacted with the AVs in a shared space. Both AVs were equipped with a 360° LED light-band eHMI attached to the outer vehicle body. Three eHMI statuses (no eHMI, static eHMI, and dynamic eHMI) were displayed. The vehicle kinematics were varied at two levels (non-yielding vs. yielding). Moreover, “non-matching” conditions were included for both AVs in which the dynamic eHMI falsely communicated a yielding intent although the vehicle did not yield. Overall, results showed that pedestrians' willingness to cross was significantly higher for the smaller AV compared to the larger AV. Regarding the interplay of vehicle kinematics and eHMI, results indicated that a dynamic eHMI increased pedestrians' perceived safety when the vehicle yielded. When the vehicle did not yield, pedestrians' perceived safety still increased for the dynamic eHMI compared to the static eHMI and no eHMI. The findings of this study demonstrated possible negative effects of eHMIs when they did not match the vehicle kinematics. Further implications for a holistic communication strategy for differently sized AVs will be discussed.

Telur Trichuris trichiura pada Bagian Luar Tubuh Lalat Musca domestica sebagai Penyebab Penyakit Trichuriasis pada Manusia

Background: Musca domestica is the most common fly species and spreading around the world also act as mechanical vectors various pathogenic agent (virus, bakteri, parasite, one of them is Trichuris trichiura). Human will suffer from Trichuriasis if they ingest food ordrinks contaminating Trichuris trichiura eggs. The prevalence of Trichuriasis is still high and it affects children more often because lack of hygiene. Purpose: to determine the role of Trichuris trichiura eggs on the body surfaces of Musca domestica thatcauses Trichuriasis in humans.Methods: Literature review by retrieving library resources from 39 journals and 2textbooksselected by using the criteria of accredited national journals sintaand reputable international journals and indexed scopus and non-scopus published by 2016.Results: From some experimental studies, Musca domestica carried Trichuris trichiura eggs on the outer body surfaces, as mechanical vectors potential for spreading Trichuriasis.Conclusion: Trichuris trichiura eggs carried by outer body surfaces of Musca domestica can causes serious health problem in humans, has potential cause Trichuriasis disease. Good control and education are needed to prevent Trichuriasis disease

Coordinated deformation and high formability mechanisms of Al–Zn–Mg–Si–Fe–Mn–Cu alloys with heterogeneous cellular structure

The formation of a heterogeneous microstructure and its effect on the deformation behavior and formability of Al–Zn–Mg–Si–Fe–Mn–Cu alloys prepared by novel thermomechanical processing were systematically investigated. The results reveal that heterogeneous microstructures, i.e., the coexistence of hard and soft microdomains and recrystallized grains with a cellular structure, were obtained in alloy sheets by the synergy of thermomechanical processing. Furthermore, mechanical property tests show that the alloy with a reasonable heterogeneous microstructure possesses a significantly enhanced formability (r = 0.7705) and a low anisotropy (Δ r = −0.047), which can make this alloy very promising in automotive outer body panel applications. In addition, based on the microstructure evolution during the whole thermomechanical processing, the formation and high formability mechanisms of heterogeneous microstructure in Al–Zn–Mg–Si–Fe–Mn–Cu alloys is proposed in this paper.

The Evolution of the Suspensory System of the Liver: A Narrative Review

Introduction &amp; ObjectiveIt is known that the viscera in the body of vertebrates participate in the major vital functions of the body, however the role of visceral mobility in the proper functioning of the musculoskeletal system remains insufficiently investigated. In order to understand the potential influence of viscera on the musculoskeletal system, we need to clarify how the suspensory system of viscera has evolved within the outer body of species at different evolutionary timepoints. More importantly, we need to determine how the suspensory system of high‐density organs, which are more prone to influencing the outer body due to their mass, adapted to different types of locomotion. This narrative review was undertaken to reconstruct the theoretical evolution of the liver and related peritoneal ligaments, to investigate its adaptation to bipedal locomotion.Materials &amp; MethodsThe primary focus of this review was the evolution of the peritoneal suspensory ligaments of the liver through documented species at specific evolutionary timepoints: annelid, agnathans, gnathostomes and tetrapods (amphibians to quadrupedal and bipedal mammals). Keyword searches in SCOPUS, PubMed, Google Scholar, and McGill Library databases were conducted in addition to manual searches of other relevant journals, textbooks and dissection manuals.ResultsQualitative studies on the gross anatomy of the liver and the suspensory peritoneal ligaments of species at different evolutionary time points were identified. A theoretical timeline of the evolution of the suspensory system of the liver was assembled.Marine species, which rely on lateral undulation, and terrestrial quadrupeds both possess a highly mobile liver and few reliably seen ligaments of suspension. This is concluded to be due to environmental demands and consequent locomotive requirements, such as running, hopping, and leaping. The human liver, in contrast, is securely attached to the diaphragm and the body walls in the upper right quadrant of the abdominal cavity via consistently present ligaments.ConclusionThis study suggests that locomotive methods led to the adaptation of ligaments that suspend high‐density organs within the body, such as the liver. Compared to other mammals, the human liver has been securely suspended to the diaphragm via peritoneal ligaments and attached to the body walls in response to two‐legged locomotion.Significance/ImplicationThis study provides a theoretical timeline of the evolution of the suspensory system of the liver related to locomotion types. Like the musculoskeletal system, it appears that the visceral suspensory ligaments adapted to the different locomotion types found over the evolutionary timeline. Over time, as species adapted, more numerous ligaments provided further attachment. This adaptation is suggestive of potential mechanical influence between the musculoskeletal system and viscera, or vice‐versa. This raises questions regarding the implication of high‐density organs on some musculoskeletal disorders.To better understand the potential mechanical influence of the human liver on the musculoskeletal system, the suspensory system of the liver and anatomical variations needs to be clearly described.

Distant trans-Neptunian object candidates from NASA’s TESS mission scrutinized: fainter than predicted or false positives?

ABSTRACT NASA’s Transiting Exoplanet Survey Satellite (TESS) is performing a homogeneous survey of the sky from space in search of transiting exoplanets. The collected data are also being used for detecting passing Solar system objects, including 17 new outer Solar system body candidates located at geocentric distances in the range 80–200 au, that need follow-up observations with ground-based telescope resources for confirmation. Here, we present results of a proof-of-concept mini-survey aimed at recovering two of these candidates that was carried out with the 4.2-m William Herschel Telescope and a QHY600L CMOS camera mounted at its prime focus. For each candidate attempted, we surveyed a square of over 1○ × 1○ around its expected coordinates in Sloan r′. The same patch of sky was revisited in five consecutive or nearly consecutive nights, reaching S/N &amp;gt; 4 at $r^{\prime }\, \lt $23 mag. We focused on the areas of sky around the circumpolar TESS candidates located at (07h:00m:15s, +86○:55′:19″), 202.8 au from Earth, and (06h:39m:47s, +83○:43′:54″) at 162.1 au, but we could not recover either of them at $r^{\prime }\, \le$23 mag. Based on the detailed analysis of the acquired images, we confirm that either both candidates are much fainter than predicted or that they are false positives.

Evidence for association of Vibrio echinoideorum with tissue necrosis on test of the green sea urchin Strongylocentrotus droebachiensis

“Sea urchin lesion syndrome” is known as sea urchin disease with the progressive development of necrotic epidermal tissue and loss of external organs, including appendages on the outer body surface. Recently, a novel strain, Vibrio echinoideorum has been isolated from the lesion of green sea urchin (Strongylocentrotus droebachiensis), an economically important mariculture species in Norway. V. echinoideorum has not been reported elsewhere in association with green sea urchin lesion syndrome. Therefore, in this study, an immersion based bacterial challenge experiment was performed to expose sea urchins (wounded and non-wounded) to V. echinoideorum, thereby mimicking a nearly natural host–pathogen interaction under controlled conditions. This infection experiment demonstrated that only the injured sea urchins developed the lesion to a significant degree when exposed to V. echinoideorum. Pure cultures of the employed bacterial strain were recovered from the infected animals and its identity was confirmed by the MALDI-TOF MS spectra profiling. Additionally, the hemolytic phenotype of V. echinoideorum substantiated its virulence potential towards the host, and this was also supported by the cytolytic effect on red spherule cells of sea urchin. Furthermore, the genome sequence of V. echinoideorum was assumed to encode potential virulence genes and were subjected to in silico comparison with the established virulence factors of Vibrio vulnificus and Vibrio tasmaniensis. This comparative virulence profile provided novel insights about virulence genes and their putative functions related to chemotaxis, adherence, invasion, evasion of the host immune system, and damage of host tissue and cells. Thus, it supports the pathogenicity of V. echinoideorum. In conclusion, the interaction of V. echinoideorum with injured sea urchin facilitates the development of lesion syndrome and therefore, revealing its potentiality as an opportunistic pathogen.

The epithelial layers of the body wall in hornerid bryozoans (Stenolaemata: Cyclostomatida).

Bryozoans are small colonial coelomates. They can be conceptualised as “origami‐like” animals, composed of three complexly folded epithelial layers: epidermis of the zooidal/colonial body wall, gut epithelium and coelothelium. We investigated the general microanatomy and ultrastructure of the hornerid (Cyclostomatatida) body wall and polypide in four taxa, including three species of Hornera and one species belonging to an undescribed genus. We describe epithelia and their associated structures (e.g., ECM, cuticle) across all portions of the hornerid body wall, including the terminal membrane, vestibular wall, atrial sphincter, membranous sac and polypide–skeletal attachments. The classic coelomate body wall composition (epidermis–ECM–coelothelium) is only present in an unmodified form in the tentacle sheath. Deeper within a zooid it is retained exclusively in the attachment zones of the membranous sac: [skeleton]–tendon cell–ECM–coelothelium. A typical invertebrate pattern of epithelial organisation is a single, continuous sheet of polarised cells, connected by belt desmosomes and septate junctions, and resting on a collagenous extracellular matrix. Although previous studies demonstrated that polypide‐specific epithelia of Horneridae follow this model, here we show that the body wall may show significant deviations. Cell layers can lose the basement membrane and/or continuity of cell cover and cell contacts. Moreover, in portions of the body wall, the cell layer appears to be missing altogether; the zooidal orifice is covered by a thin naked cuticle largely devoid of underlying cells. Since epithelium is a two‐way barrier against entry and loss of materials, it is unclear how hornerids avoid substance loss, while maintaining intracolonial metabolite transport with imperfect, sometimes incomplete, cell layers along large portions of their outer body surface.

Compact object mergers in hierarchical triples from low-mass young star clusters

Abstract A binary star orbited by an outer companion constitutes a hierarchical triple system. The outer body may excite the eccentricity of the inner binary through the von Zeipel-Lidov-Kozai (ZLK) mechanism, triggering the gravitational wave (GW) coalescence of the inner binary when its members are compact objects. Here, we study a sample of hierarchical triples with an inner black hole (BH) – BH binary, BH – neutron star (NS) binary, and BH – white dwarf (WD) binary, formed via dynamical interactions in low-mass young star clusters. Our sample of triples was obtained self-consistently from direct N-body simulations of star clusters which included up-to-date stellar evolution. We find that the inner binaries in our triples cannot merge via GW radiation alone, and the ZLK mechanism is essential to trigger their coalescence. Contrary to binaries assembled dynamically in young star clusters, binary BHs merging in triples have preferentially low mass ratios (q ≃ 0.3) and higher primary masses ($m_{\rm p} \gtrsim 40 {\, \rm M_\odot }$). We derive a local merger rate density of 0.60, 0.11 and $0.5 {-1} \, \rm Gpc^{-3}$ for BH-BH, BH-NS and BH-WD binaries, respectively. Additionally, we find that merging binaries have high eccentricities across the GW spectrum, including the LIGO-Virgo-KAGRA (LVK), LISA, and DECIGO frequencies. About 7 per cent of BH-BH and 60 per cent of BH-NS binaries will have detectable eccentricities in the LVK band. Our results indicate that the eccentricity and the mass spectrum of merging binaries are the strongest features for the identification of GW mergers from triples.

Genome-wide insights into adaptive hybridisation across the Schistosoma haematobium group in West and Central Africa.

Schistosomiasis remains a public health concern across sub-Saharan Africa; current control programmes rely on accurate mapping and high mass drug administration (MDA) coverage to attempt disease elimination. Inter-species hybridisation can occur between certain species, changing epidemiological dynamics within endemic regions, which has the potential to confound control interventions. The impact of hybridisation on disease dynamics is well illustrated in areas of Cameroon where urogenital schistosomiasis, primarily due to Schistosoma haematobium and hybrid infections, now predominate over intestinal schistosomiasis caused by Schistosoma guineensis. Genetic markers have shown the ability to identify hybrids, however the underlying genomic architecture of divergence and introgression between these species has yet to be established. In this study, restriction site associated DNA sequencing (RADseq) was used on archived adult worms initially identified as; Schistosoma bovis (n = 4), S. haematobium (n = 9), S. guineensis (n = 3) and S. guineensis x S. haematobium hybrids (n = 4) from Mali, Senegal, Niger, São Tomé and Cameroon. Genome-wide evidence supports the existence of S. guineensis and S. haematobium hybrid populations across Cameroon. The hybridisation of S. guineensis x S. haematobium has not been demonstrated on the island of São Tomé, where all samples showed no introgression with S. haematobium. Additionally, all S. haematobium isolates from Nigeria, Mali and Cameroon indicated signatures of genomic introgression from S. bovis. Adaptive loci across the S. haematobium group showed that voltage-gated calcium ion channels (Cav) could play a key role in the ability to increase the survivability of species, particularly in host systems. Where admixture has occurred between S. guineensis and S. haematobium, the excess introgressive influx of tegumental (outer helminth body) and antigenic genes from S. haematobium has increased the adaptive response in hybrids, leading to increased hybrid population fitness and viability.