Bathyal Research Articles

Characterization of Pseudoterranova ceticola (Nematoda: Anisakidae) larvae from meso/bathypelagic fishes off Macaronesia (NW Africa waters)

The genus Pseudoterranova includes parasite species of cetaceans and pinnipeds. The third stage larva (L3) of seal-infecting species occur in second intermediate or paratenic fish hosts mainly in neritic waters. This study firstly describes a Pseudoterranova L3 from meso/bathypelagic fishes off Macaronesia. L3s were morphologically and genetically studied by light microscopy and sequencing of the mtDNA cox2 and entire ITS rDNA genes. Bayesian inferences were performed with sequences from the larvae and selected sequences from GenBank. The nematode L3s were molecularly identified as Pseudoterranova ceticola, a parasite of kogiid whales. Such larvae were collected from Bolinichthys indicus, Chauliodus danae, Eupharynx pelecanoides, Diaphus rafinesquii, D. mollis, Diretmus argenteus and Maulisia argipalla. They mainly occurred in the viscera of these fishes. Pseudoterranova ceticola L3 were small (< 12 mm) and whitish, and a prominent characteristic is a circumoral ridge extending from the ventral boring tooth which differentiate them from Pseudoterranova spp. L3 maturing in pinnipeds and Terranova sensu lato larvae that mature in poikilotherms. The shape of the tail: conical, long, pointed, ventrally curved and lacking mucron also distinguish these larvae from those of the pinniped-infecting Pseudoterranova spp. Phylogenetic analyses based on mtDNA cox2 and ITS rDNA sequences suggest that P. ceticola is closely related to Skrjabinisakis spp., and not with Pseudoterranova spp. parasitizing pinnipeds. The related species Skrjabinisakis paggiae, S. brevispiculata and S. physeteris (until recently belonging to genus Anisakis), are as P. ceticola also parasites of physeteroid cetaceans. The morphology and morphological variation of the larvae of the cetacean parasite P. ceticola is thoroughly described for the first time. These L3 can readily be morphologically distinguished from those of the pinniped-infecting Pseudoterranova spp. The parasite likely completes its life cycle in the mesopelagic and bathypelagic realm, with meso/bathypelagic fish as 2nd intermediate or paratenic hosts and kogiids as final host. Thus, Pseudoterranova from cetaceans appear to be morphologically, genetically, and ecologically differentiated to those from pinnipeds, suggesting that they are not congeneric.

Surface productivity gradients govern changes in the viability of deep ocean prokaryotes across the tropical and subtropical Atlantic

AbstractProkaryotes represent a major fraction of marine biomass and play a key role in the global carbon cycle. We studied the vertical profiles (0–3500 m) of abundance, viability, and activity of prokaryotic communities along a productivity gradient in the subtropical and tropical Atlantic to assess whether there is a vertical linkage between surface productivity regimes and deep ocean prokaryotic communities. We found that latitudinal changes in the vertical patterns of cytometric variables were coupled with surface productivity: higher prokaryotic abundances and viabilities, and smaller cell sizes were observed below highly productive surface waters, an effect reaching down to the bathypelagic layer. Leucine uptake rates in deep waters showed no clear relationship with surface productivity. Changes in resource and energy allocation to growth vs. maintenance in hostile environments, cell‐size‐dependent metabolic requirements, and variability in leucine‐to‐carbon conversion may all be part of the array of factors involved in controlling the prokaryotic activity patterns that were measured. Our work adds to the recent findings that highlight the importance of vertical connectivity for prokaryotic communities in the dark ocean and unveils a remarkable impact of surface conditions in the viability of deep ocean prokaryotes. This is a key aspect when considering metabolic rates of prokaryotic communities in the bathypelagic realm.

Population structure and habitat preference of cave crickets (&lt;i&gt;Rhaphidophora&lt;/i&gt; sp. (Orthoptera: Rhaphidophoridae)) in Sanghyang Kenit cave, Citatah karst area, West Java

Cave crickets are considered as a keystone species that can be used as a cave ecosystem bioindicator. Developing caves as tourism has considerable potential to disturb cave cricket populations. This study aimed to investigate cave cricket population structure and their habitat preference in Sanghyang Kenit cave one year after it developed into a show cave. Data were collected through standardized visual searching in three cave zones: entrance, twilight, and dark. Besides cave crickets, other macroarthropods discovered in each zone were also recorded. Abiotic parameters of habitat comprised air and soil temperatures, RH, soil moisture, soil pH, and light intensity were measured. Data were analyzed to show cave crickets abundance, density, sex ratio, and age structure. Statistical analysis comprising Kruskal Wallis, non-metric multidimensional scaling, and correlation tests were performed. The cave cricket population in Sanghyang Kenit belonged to a single species, Rhaphidophora sp. The population was around 78-108 individuals and distributed in all cave zones. The abundance and density in twilight and dark zones were significantly higher than in the entrance. The number of males outperformed females with a 2.16 ratio. Besides, the population was dominated by the sub-adult class. Environmental parameters of twilight and dark zones tended to be similar to one another compared to the entrance. Cave crickets preferred habitats with dark, humid, and acidic soil pH. Heteropoda sp. and Catagaeus sp. were considered potential predators. This study implies the importance of protecting cave crickets in Sanghyang Kenit.

Role of coping material type and collarles margin design toward fracture resistance of metal porcelain restoration

Aims: Metal-porcelain restoration is currently the most popular restoration that can be used for the anterior teeth. However the collar coping design on facial margin gingiva causes dark and shadowed zone in gingival, which is called "Umbrella Effect". This situation can overcomed by using collarless coping design. But this coping design has weaknesses such as decrease the fracture resistance of retoration. In some previous studies, the type of coping material can also affect fracture resistance. this study aimed to determined the effect of the coping material tipe and collarless margin design on the fracture resistance of restoration. Material and Methode: A total of 24 samples of metal-porcelain restorations from two material type and design were fabricated and cemented on 24 metal dies. The study was divided into four groups; Group A with Ni-Cr and Full Metal Collarless, Group B with Ni-Cr and Modified Metal Collarless, Group C with Co-Cr and Full Metal Collarless, and Group D with Co-Cr and Modified Metal Collarless. The measurement of fracture resistance was carried out using universal testing machine (Torsee UTM AMU-10, Tokyo, Japan) at a crosshead speed of 0.05 mm/minute. Loading point was applied at an angle of 45° until the porcelain layer fractured.

Redundant apodization for direct imaging of exoplanets

Context. Telescope pupil fragmentation from spiders generates specific aberrations that have been observed at various telescopes and are expected on the 30-meter class telescopes under construction. This is known as the island effect, and it induces differential pistons, tips, and tilts on the pupil petals, deforming the instrumental point spread function (PSF); it is one of the main limitations to the direct detection of exoplanets with high-contrast imaging. These petal-level aberrations can have different origins such as the low-wind effect or petaling errors in the adaptive optics reconstruction. Aims. In this paper, we propose a method for alleviating the impact of the aberrations induced by island effects on high-contrast imaging by adapting the coronagraph design in order to increase its robustness to petal-level aberrations. Methods. Following a method first developed and applied on robustness to errors due to primary mirror segmentation (e.g., segment phasing errors, missing segments), we developed and tested redundant apodized pupils (RAP): apodizers designed at the petal-scale, then duplicated and rotated to mimic the pupil petal geometry. Results. We applied this concept to the ELT architecture, made of six identical petals, to yield a 10−6 contrast in a dark region from 8 to 40λ/D. Both amplitude and phase apodizers proposed in this paper are robust to differential pistons between petals, with minimal degradation to their coronagraphic PSFs and contrast levels. In addition, they are also more robust to petal-level tip-tilt errors than classical apodizers designed for the whole pupil, with which the limit of contrast of 10−6 in the coronagraph dark zone is achieved for constraints up to 2 rad RMS of these petal-level modes. Conclusions. In this paper the RAP concept proves its robustness to island effects (low-wind effect and post-adaptive optics petaling), with an application to the ELT architecture. It can also be considered for other 8- to 30-m class ground-based units such as VLT/SPHERE, Subaru/SCExAO, GMT/GMagAO-X, and TMT/PSI.

26.4: Force‐induced Tunable Lens for Dark‐zone Compensation in Stretchable Display

Lens array is an important component for optimizing display performances. In this paper, we further explore the lens array structure for future stretchable displays. This work proposed the force‐induced tunable lens with an adjustable diopter triggered by applied strain. Furthermore, we introduced an optical compensation method to solve the dark zone problem with this tunable lens. The optical simulation result shows the feasibility of this method used in a display array.

Isolation performance metrics for personal sound zone reproduction systems.

Two isolation performance metrics, inter-zone isolation (IZI) and inter-program isolation (IPI), are introduced for evaluating personal sound zone (PSZ) systems. Compared to the commonly used acoustic contrast metric, IZI and IPI are generalized for multichannel audio and quantify the isolation of sound zones and of audio programs, respectively. The two metrics are shown to be generally non-interchangeable and suitable for different scenarios, such as generating dark zones (IZI) or minimizing audio-on-audio interference (IPI). Furthermore, two examples with free-field simulations are presented and demonstrate the applications of IZI and IPI in evaluating PSZ performance in different rendering modes and PSZ robustness.

3.1: Force‐induced Tunable Lens for Dark‐zone Compensation in Stretchable Display

3.1: Force‐induced Tunable Lens for Dark‐zone Compensation in Stretchable Display

Geochemical and Cathodoluminescence Properties as Discriminators to Characterize K-Feldspar in Different Genetic Settings

ABSTRACTPotassic alteration is a common feature in hydrothermal ore systems, and both its occurrence and degree can be important features applicable to ore deposit exploration. Here we report results from optical cathodoluminescence (CL) and chemical composition investigations on K-feldspar of different origins in and around the Early Cretaceous lode gold deposits in the Xiaoqinling area, located along the southern margin of the North China Craton.We focus on K-feldspars from an Early Cretaceous biotite monzogranite (G-Kfs), a Paleoproterozoic migmatite (M-Kfs), and a hydrothermal alteration zone of Early Cretaceous gold deposits (H-Kfs). The grain size of G-Kfs ranges from 1 to 4 mm, usually exhibits tartan twinning, and occasionally shows evidence of exsolution. Part of the M-Kfs exhibits tartan twinning, and the grain size shows wide variation (from tens of microns to several centimeters), while the H-Kfs shows no twinning, and the grain size is generally less than 0.5 mm.Optical CL analyses show that the G-Kfs exhibits two emission bands at around 466–472 and 708–713 nm which occur in multiple, alternating dark red and blue zones. The M-Kfs exhibits blue, red, and/or violet-red luminescence resulting from two emission bands at 446–465 and 694–701 nm. The H-Kfs displays a distinct greenish-yellow luminescence resulting from an emission band at 545–550 nm.Electron probe microanalyses show that among the three K-feldspar types, the G-Kfs contains higher Na2O (average: 0.71 wt.%) and Al2O3 (average: 18.79 wt.%) and lower K2O (average: 15.62 wt.%), whereas the H-Kfs shows higher K2O (average: 16.31 wt.%) and lower Na2O (average: 0.45 wt.%) and Al2O3 (average: 18.61 wt.%). The K2O, Na2O, and Al2O3 contents of the M-Kfs are intermediate between those of the G-Kfs and H-Kfs. In transitioning from the G-Kfs, M-Kfs, to H-Kfs, it is noted that the concentrations of Sr, Ba, and Pb decrease progressively, whereas W, V, Zn, Mn, Sc, Ge, and Ga gradually increase. Concentrations of La, Ce, and Eu in the H-Kfs are lower than in the G-Kfs and M-Kfs, and the Cr and Cu concentrations in the G-Kfs are the lowest. Scatter diagrams constructed with Sr, Ba, Pb, and Rb concentrations show that the three types of K-feldspars fall into different fields. These, as well as the CL and spectral properties of K-feldspar, can clearly distinguish the K-feldspars of magmatic, metamorphic, and hydrothermal origin in the study area.

Two new species of the genus Amiantofusus (Gastropoda: Fasciolariidae) from seamounts in the tropical western Pacific, with remarks on the taxonomy of A. candoris and A. sebalis

During two scientific expeditions to the seamounts near the Mariana Trench in the tropical western Pacific, two undescribed gastropod species belonging to the genus Amiantofusus Fraussen et al., 2007 were collected from the upper bathyal zone. In the present study, we describe and illustrate them as new species. Amiantofusus granulus sp. nov. was collected from Magellan and Caroline Seamounts at depths of 1357–1473 m, and Amiantofusus tchangsii sp. nov. was discovered from Caroline Seamounts at depths of 1893–2291 m. The new species are distinguished from each other and congeners by shell morphology. Phylogenetic analyses based on the cytochrome oxidase c subunit I (COI) gene using Bayesian inference indicate that Amiantofusus granulus sp. nov. is a sister group to other congeners, and Amiantofusus tchangsii sp. nov. shows a close relationship with Amiantofusus sp. JQ950210 from the Philippines. The results provide additional support for the assignment of the new species to the genus Amiantofusus and their separation from congeners. In addition, our molecular analysis reveals that Amiantofusus candoris Fraussen et al., 2007 and Amiantofusus sebalis Fraussen et al., 2007 have almost identical COI sequences. Their taxonomic relationship is briefly discussed, and it is concluded that A. candoris should be regarded as a junior synonym of A. sebalis.

Exome sequencing as a first-tier test for copy number variant detection: retrospective evaluation and prospective screening in 2418 cases

BackgroundDespite the availability of whole exome (WES) and genome sequencing (WGS), chromosomal microarray (CMA) remains the first-line diagnostic test in most rare disorders diagnostic workup, looking for copy number variations...

Termination of CD40L co-stimulation promotes human B cell differentiation into antibody-secreting cells.

Human naïve B cells are notoriously difficult to differentiate into antibody-secreting cells (ASCs) in vitro while maintaining sufficient cell numbers to evaluate the differentiation process. B cells require T follicular helper (TFH ) cell-derived signals like CD40L and IL-21 during germinal center (GC) responses to undergo differentiation into ASCs. Cognate interactions between B and TFH cells are transient; after TFH contact, B cells cycle between GC light and dark zones where TFH contact is present and absent, respectively. Here, we elucidated that the efficacy of naïve B cells in ACS differentiation is dramatically enhanced by the release of CD40L stimulation. Multiparameter phospho-flow and transcription factor (TF)-flow cytometry revealed that termination of CD40L stimulation downmodulates NF-κB and STAT3 signaling. Furthermore, the termination of CD40 signaling downmodulates C-MYC, while promoting ASC TFs BLIMP1 and XBP-1s. Reduced levels of C-MYC in the differentiating B cells are later associated with crucial downmodulation of the B cell signature TF PAX5 specifically upon the termination of CD40 signaling, resulting in the differentiation of BLIMP1 high expressing cells into ASCs. The data presented here are the first steps to provide further insights how the transient nature of CD40 signaling is in fact needed for efficient human naïve B cell differentiation to ASCs.

Planar bioluminescent cytotoxicity assay via genetically modified adherent human reporter cell lines, applied to authenticity screening of Saussurea costus root

The hyphenation of high-performance thin-layer chromatography to effect-directed assays is a very straightforward way to detect individual bioactive zones, and at the same time, to investigate several samples simultaneously. The combination of the separation technique with adherent human cells applied on the same surface was recently shown to be possible. Since on-surface adherent cell assays are in their infancy, a planar bioluminescent cytotoxicity assay was developed to expand the possibilities. Human embryonic kidney (HEK) 293 or HeLa (cervical carcinoma) cells were chosen because of their fast growth rates and high rates of successful transfection, being suitable for the generation of genetically modified reporter cells. For the first time, HeLa cells were visualized on the wettable reversed phase plate surface using digital microscopy. For the generation of bioluminescent reporter cells, vectors for the expression of three luciferase enzymes of various origins were tested. The genetically modified HEK 293T-CMV-ELuc cells were the best suitable for the new planar cytotoxicity assay due to the faster growth rate, robustness, and stronger bioluminescence signal. The stable expression of luciferase under the control of a strong constitutive promoter allowed the cells to be used for the determination of the cytotoxicity of Saussurea costus root samples obtained from the market and to assess the authenticity of these samples. Any cytotoxic zone was detected as a dark zone inhibiting the cell bioluminescence. Five replicates of the dose-response curve confirmed the good assay performance and the cytotoxicity of a zone, which was assigned to costunolide and dehydrocostus lactone. By this, the proof-of-principle of the new planar bioluminescent cytotoxicity assay, which does not require expensive licensing, was successful.

Analysis of the Impact of Acoustic Vibrations on the Laser Beam Remelting Process.

The article contains an analysis of selected aspects of the structure and properties of laser remelting of low carbon steel supported by acoustic vibrations obtained in the research presented in (A Novel Method of Supporting the Laser Welding Process with Mechanical Acoustic Vibrations). Due to the assumptions made in this publication, it was necessary to deepen the analysis of the obtained results. The correlation of such factors on the structure as the frequency of vibrations (50, 100, 1385 Hz), their propagation through the short-lived liquid phase and changes in the structure, chemical composition, and hardness of the characteristic zones of the obtained remelting was considered. The remelting obtained with the participation of resonant acoustic vibrations with a frequency of 1385 Hz was subjected to thermo-mechanical analysis. A characteristic “bandwidth” pattern was revealed in the structure. In the present article, a thermo-mechanical analysis of the cause of its formation was carried out by comparing it with the remelting obtained at lower frequencies. As a result of the analysis, it was found that the band structure was characterized by 7 to 8 areas up to approximately a 90 µm depth, which showed dark and light zones. These areas differed in carbon content, hardness, and width. The analysis of vibration propagation helped to determine that in the time of crystallization of the molten metal pool, the transition of the vibration wave lasted through 7–8 minima and maxima. This fact allows us to assume with a high probability that it is the result of the applied resonance frequency.

Brachiopod Fauna from the Deep Mediterranean Sea: Distribution Patterns and Ecological Preferences

Compared to their fossil counterparts, living brachiopods are investigated far less often, due to their occurrence in remote environments such as dark caves or deep environments. Due to the scarcity of studies targeting in situ brachiopods’ populations, large-scale information on their distribution and ecological preferences is still lacking, especially on hardgrounds. The extensive employment of remotely operated vehicles (ROVs), however, has opened up the chance to better explore this taxon’s diversity and ecology in the mesophotic and bathyal zones. The analysis of over 600 h of video footage collected from 624 sites, from 40 m to 1825 m, located along the Ligurian and Tyrrhenian coasts of Italy and the Sicily Channel, allowed for a large-scale investigation. The four identified species, Novocrania anomala, Gryphus vitreus, Megerlia truncata and Terebratulina retusa, emerged as common macrofaunal components of the explored habitats, especially between 150 m and 250 m, with high occurrences in the northern areas, especially on offshore seamounts. All species can form dense aggregations of individuals, with M. truncata showing the densest populations on steep rocky terraces (up to 773 individuals m−2). Except for G. vitreus, the only species also recorded on soft bottoms, the others were found exclusively on hardgrounds, with N. anomala showing a peculiar ability to exploit anthropogenic substrates such as terracotta amphorae. No stable species-specific associations were noted, even if numerous species were frequently observed together. Although brachiopods do not show the conspicuous tridimensionality of large filter-feeders, their substrate occupancy and their role in pelagic–benthic processes support their importance in deep-sea Mediterranean ecosystems.

Implementation of a dark zone maintenance algorithm for speckle drift correction in a high contrast space coronagraph

Due to the limited number of photons, directly imaging planets requires long integration times with a coronagraphic instrument. The wavefront must be stable on the same time scale, which is often difficult in space due to time-varying wavefront errors from thermal gradients and other mechanical instabilities. We discuss a laboratory demonstration of a photon-efficient dark zone maintenance (DZM) algorithm in the presence of representative wavefront error drifts. The DZM algorithm allows for simultaneous estimation and control while obtaining science images and removes the necessity of slewing to a reference star to regenerate the dark zone mid-observation of a target. The experiments are performed on the high-contrast imager for complex aperture telescopes at the Space Telescope Science Institute. The testbed contains an IrisAO segmented primary surrogate, a pair of continuous Boston Micromachine (BMC) kilo deformable mirrors (DMs), and a Lyot coronagraph. Both types of DMs are used to inject synthetic high-order wavefront aberration drifts into the system, possibly similar to those that would occur on telescope optics in a space observatory, which are then corrected by the BMC DMs via the DZM algorithm. In the presence of BMC, IrisAO, and all DM wavefront error drift, we demonstrate maintenance of the dark zone contrast (5.8 − 9.8 λ / Dlyot) at monochromatic levels of 8.5 × 10 − 8, 2.5 × 10 − 8, and 5.9 × 10 − 8, respectively. In addition, we show multiwavelength maintenance at a contrast of 7.0 × 10 − 7 over a 3% band centered at 650 nm (BMC drift). We demonstrate the potential of adaptive wavefront maintenance methods for future exoplanet imaging missions, and our demonstration significantly advances their readiness.

Metabarcoding and Metabolome Analyses Reveal Mechanisms of Leymus chinensis Growth Promotion by Fairy Ring of Leucocalocybe mongolica

Fairy rings are a unique ecological phenomenon caused by the growth of the fungal mycelium in the soil. Fairy rings formed by Leucocalocybe mongolica (LM) are generally distributed in the Mongolian Plateau, where they promote plant growth without fertilization and alleviate fertilizer use. We previously investigated the soil factors regulating growth promotion in a fairy ring ecosystem; however, the aspects of the plant (Leymus chinensis, LC) that promote growth have not been explored. Therefore, the present study investigated the endophyte diversity and metabolome of LC in an LM fairy ring ecosystem. We analyzed the leaf and root samples of LC from the DARK (FR) and OUT (CK) zones. The fairy rings significantly improved the fungal diversity of roots and leaves and the bacterial diversity of leaves in the FR zone. Ralstonia was the dominant bacteria detected in the LC leaves. In addition, Marasmius, another fairy ring fungal genus, was also detected with a high abundance in the roots of the FR zone. Furthermore, widely targeted metabolome analysis combined with KEGG annotation identified 1011 novel metabolites from the leaves and roots of LC and seven pathways significantly regulated by the fairy ring in the FR zone. The fairy ring ecosystem significantly downregulated the flavonoid metabolism in the leaves and roots of LC. The correlation analysis found Ralstonia is a potential regulatory factor of flavonoid biosynthesis in LC. In addition, salicylic acid and jasmonic acid were found upregulated in the leaves, probably related to Marasmius enrichment. Thus, the study details plant factors associated with enhanced growth in an LM fairy ring ecosystem. These findings lay a theoretical foundation for developing the fairy ring ecosystem in an agricultural system.

Effect of α-AlH3 content on ignition and combustion characteristics of multicomponent mixtures

Aluminum hydride (alane, AlH3) is a promising energetic material that can significantly increase the specific impulse of propellants while lowering the combustion temperature. In this work, a CO2 laser was adopted to investigate the effect of α-AlH3 content on the ignition and combustion characteristics of AlH3–Al, AlH3–ammonium perchlorate (AP), AlH3–Al–AP, and AlH3–Al–AP–hydroxyl-terminated polybutadiene (HTPB) mixtures (namely, samples DAl, DAP, T, and Q, respectively). The DAl samples formed a mushroom flame at the beginning of combustion due to the Kelvin-Helmholtz effect under the heat flow generated by the combustion of H2 released from AlH3. The rapid hydrogen release caused the flame to break away from the sample to form a “dark zone”, whose height gradually shortened. The high AlH3 content promoted the decomposition of HTPB to C4 species, resulting in a “dark zone” for Q samples during ignition. The DAP and T samples combusted intensely with lower ignition delay time (ti) and combustion time (tc) and higher maximum combustion temperature (Tmax) than the other two samples due to the AP. The combustion temperatures of the mixed samples were effectively decreased, while the combustion rates were also accelerated by partially replacing Al with AlH3. As the rate of AlH3:Al was increased from 1:3 to 3:1, the Tmax of the DAl, T, and Q samples decreased by 113, 276, and 128 K, respectively, whereas tc decreased by 16.18 %, 32.11 %, and 8.18 %, respectively. However, the ti of the Q samples increased with increasing AlH3, probably because a large amount of hydrogen release exacerbated the effect of the porous layer, thus hindering the escape of the gas phase products. In addition, only weak Al(g) characteristic emission spectra were observed during combustion, which is due to the HTPB adhesion largely inhibiting the combustion of metallic fuels.

Correlation between environmental factors and springtail species (Hexapoda: Collembola) inhabiting Jangamgul Cave of Korea

This study was conducted with the purpose of comparing Collembolan species composition among habitats inside the cave and finding environmental variables that affect this species composition. Using a semi-quantitative sampling method, we studied the correlation between Collembolan species and environmental factors. Sampling frequencies were once every two months from May 2019 to May 2020 in three ecological zones. Collembola inhabiting inside Jangamgul Cave were found to have totaled 20 species, 15 genera, and 8 families. The highest Shannon diversity index was observed in site 1 with the highest abundance. There was, however, no significant difference in all species community indices. Soil moisture, air humidity, and soil pH showed significant differences between the three zones. However, Collembolan species composition seems to be more related to favorite environmental characteristics such as organic materials and habitat conditions than to these specific factors. Gulgastrura reticulosa Yosii, 1966, although found in the entrance zone, showed the characteristics of troglobite species because this zone has sparse places covered with leaf litter and soil which are called microcavern. Mesogastrura sp. was collected mostly from bat guano with soil piled up at twilight zone and dark zone with varying temperature. This species is considered guanophilous like other Mesogastrura species reported in caves of Europe.

Pulsating self-snapping of a liquid crystal elastomer bilayer spherical shell under steady illumination

Self-oscillation can absorb energy from constant external environment to maintain its own continuous motion, and has potential application in the fields of soft robotics, motors, military industry and so on. Inspired by the intermittent predation of Venus fly-trap, we creatively develop a pulsating self-snapping system in this paper, which is composed of liquid crystal elastomer (LCE) bilayer spherical shell under steady illumination. Based on shallow shell theory and dynamic LCE model, a nonlinear dynamic model of self-snapping shell is formulated. Through quasi-static analysis, the self-snapping of LCE bilayer shell under steady illumination is investigated by utilizing the modified iteration method. The LCE bilayer shell under steady illumination can develop into two motion regimes, namely the static regime and the self-snapping regime. The snapping-through of bilayer shell results from the light-driven bending moments tending to flatten the shell, and the self-snapping can be maintained by transforming between snap-through in illumination zone and snap-back in dark zone. In addition, the critical conditions for triggering self-snapping, and its energy release ratio are investigated in detail. Different from the existing abundant self-oscillating systems, this self-snapping system has advantages of large displacement, rapid energy release and high energy release ratio, and may pave a new way for the development of jumping robotics, actuated devices, military industry and so on.