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Trematodes found in the enteropneust hemichordates are described for the first time. Metacercariae have been found in the trunk coelom, in the collar coelom, in the proboscis coelom, and in the glomerulus of the deep-sea torquaratorid Quatuoralisia malakhovi Ezhova et Lukinykh, 2022. This is the first find of parasites in the glomerulus of acorn worms. The taxonomy of the found trematodes is discussed.

Frenulate siboglinids are a characteristic component of communities living in various reducing environments, including sites with hydrocarbon seeps. High concentrations of hydrocarbons in the sediments of the Arctic basin seas, including the Barents Sea, suggest the presence of a rich siboglinid fauna there. This reflects the fact that microbiological oxidation of methane occurs under reducing conditions, generating high concentrations of hydrogen sulfide in the sediment. This hydrogen sulfide acts as an energy source for the sulfide-oxidizing symbionts of siboglinids. Here we report on the findings of the frenulate siboglinid species Nereilinum murmanicum made between 1993 and 2020 in the Barents Sea. These data significantly expand the range of this species and yield new information on its habitat distribution. The depth range of N. murmanicum was 75–375 m. The species was most abundant from 200 to 350 m and was associated with temperatures below 3 °C and salinities from 34.42 to 35.07. Most of the findings (43 locations or 74%) fall on areas highly promising for oil and gas production. Twenty-eight locations (48%) are associated with areas of known oil deposits, 22 locations (37%) with explored areas of gas hydrate deposits. N. murmanicum was also found near the largest gas fields in the Barents Sea, namely Shtokman, Ludlovskoye and Ledovoye.

In this article, results are presented of experiments on depositing charged particles, which imitate the levitating dust on the Moon, on stainless steel. Ensembles of particles are created above the surface of laboratory regolith whose composition and particle size distribution imitate the dust that covers the Moon’s surface. Under the action of the gyrotron radiation on regolith, non-linear physical-chemical processes develop (breakdown, chain plasmachemical reactions, and particle scattering by the Coulomb mechanism), which lead to the appearance of a levitating cloud of particles. The simulation experiment is based on the similarity between the processes that develop in the laboratory experiments with regolith and the processes that occur on the Moon during its bombardment by micrometeorites. The effect of the levitating cloud on stainless steel plates is studied and it is shown that regolith particles in the shape of spheroids of different sizes are deposited on the surface of the plates. The dimensions of the deposited particles and the density of their placement depend on the quality of treatment of the plate surface. It is shown that the laboratory-produced dusty plasma can be used in simulation experiments to study the modification of surfaces of different materials for space technology.

An Erratum to this paper has been published: https://doi.org/10.1134/S0010952522330012

The article presents a report on the findings of representatives of frenulate pogonophorans Nereilinum murmanicum in the northern and central parts of the Barents Sea, which significantly expands the range of this species and provides guidance on its distribution in this basin. Here we present the coordinates of new finds with an indication of the depth. Find points were associated with data on known and potential hydrocarbon deposits.

The problem of the origin of the metazoan life cycle is analyzed on the base of various hypotheses on the origin of multicellular animals. According to the Gastraea theory and the Phagocytella theory, the ancestral metazoan life cycle was holopelagic. In the framework of the hypotheses of the primary sedentarity, the metazoan ancestor had a pelago-benthic life cycle with floating larvae, the synzoospores. In accordance with this hypothesis, Eumetazoa originated from the progenetic larvae of the sedentary ancestor. The primary life cycle of Eumetazoa (i.e., metazoans with a nervous system, musculature, mouth, and gut) was holopelagic. Particularly this life cycle is typical for recent Ctenophora, which is the earliest branch of the eumetazoans. Cnidaria and Bilateria are sister groups. Their last common ancestor acquired the pelago-benthic life cycle de novo. The pelagic part of the life cycle of cnidarians is comprised of the blastula and gastrula stages only. Some anthozoans still maintain the planktotrophic gastrula larvae in their life cycles. Planulae of Medusozoa are simplified lecithotrophic larvae that had lost the function of spread because of the appearance of the medusa stage in the life cycle. In triploblastic Bilateria, the prolongation of the pelagic stage of the life cycle occurred due to the appearance of the ciliated bilaterally symmetrical larvae, which are actually the juveniles raised into the water column. This phylogenetic modus can be designated by the special term “larvalization.” Thus, the ciliated pelagic larvae of all bilaterians have a common origin from the juvenile stages of the last common bilaterian ancestor. Their ciliated bands came from the modified ciliated tentacular apparatus of juvenile stages of the last common bilaterian ancestor. Homologous elements in the ciliated bands of trochozoan and deuterostomian larvae are traced.

The application of the general principles of the non-equilibrium thermodynamics and stoichiography allows obtaining novel information on the solid-phase transformations happening in multielement and heterophase substances and materials. Without the solid-phase standards, the use of stoichiography allows detecting, identifying and quantitative determining known and unknown crystalline and amorphous phases being of constant or variable composition. For the first time, reliable results concerning evolution of solid products during preparation of the Mo-V-Te-Nb-O catalyst of propane ammoxidation are presented.

The application of general principles of nonequilibrium thermodynamics and stoichiography allows obtaining novel information on the solid-phase transformations of multielement and heterophase substances and materials. Without solid-phase standards, the use of stoichiography makes it possible to detect, identify, and quantify known and unknown crystalline and amorphous phases of constant or variable composition. For the first time, reliable results are presented concerning the evolution of solid products in the course of preparation of the Mo–V–Te–Nb–O catalyst of propane ammoxidation.

Allometric growth in post-embryonic development was studied in the hydrothermal vestimentiferan Oasisia alvinae Jones, 1985. In the process of growth, the length of the trunk region increases relative to the total body length from 51 to 83.4%, whereas the relative sizes of the obturacular region, vestimental region, and the opisthosoma decrease. This is connected with a strong development of the trophosome and gonads in the trunk region. It is suggested that the predominant growth of the trunk region during ontogeny is a common pattern for all vestimentiferans. We discuss the differences in body proportions of vestimentiferans that live in hydrothermal vents and vestimentiferans of cold hydrocarbon seeps.

A minimisation of an appropriate characteristic function (such as the Gibbs energy) of a system resulting in establishing its equilibrium state does not require a notion of component's activity, wh...

During the growth of hydrothermal vestimentiferan Oasisia alvinae the trunk part of body was found to be elongated (from 51 to 83.4% of the overall body length), while the relative dimensions of all other body regions decreased. This was related to the enhanced trophosome and gonad development in the trunk part. We suppose that predominant trunk growth is a common feature of all vestimentiferans.

The structure of early juvenile specimens of vestimentifera Ridgeia piscesae (Annelida, Siboglinidae) was studied. As adults, vestimentiphers are deprived of the intestine and have a trophosome, in which cells chemoautotrophic bacteria are living. In early juvenile individuals of 280-300 microns in size, it was found that trophosome develops from cells of the coelomic lining on the surface of the intestine and on the side walls of the body. This structure of the rudiment of the trofosome suggests that the bacteria are first captured by the cell wall of the body and then transferred to the cell on the surface of the intestine.

Siboglinids (Annelida, Siboglinidae) as possible indicators of carbohydrates on the case of the Sea of Okhotsk Geographical and bathymetric distribution of siboglinides in the sea of Okhotsk was studied. More than 75% of all siboglinides were found at a depth of 400 m. These findings were mainly concentrated in the North-Western part of the shelf. A comparison of the distribution of siboglinides in the Sea of Okhotsk and generalized geological data on the distribution of hydrocarbons showed that siboglinides in the sea of Okhotsk were mostly found in the areas of hydrocarbon manifestations and were absent in the central regions, where in the bottom sediments and in the near-surface layer of water we have registered minimal methane and hydrocarbon concentrations.

The aim of the work was to compare postural performance during kneeling and standing between different modes of ventilation. Body stability was assessed using a force platform in healthy volunteers (n = 48) during quiet breathing (QB), breath holding (BH), and hyperventilation (Hyp) in the kneeling and standing positions. The mean velocity of the center of pressure (CP) displacement and the postural sway amplitude were estimated in the anteroposterior and mediolateral planes. The breathing amplitude and respiration rate were evaluated using a strain gauge. In general, the CP displacement amplitude in the mediolateral plane was lower and mean velocity higher during kneeling than during standing. The results gave grounds to assume that the kneeling posture was accompanied by a higher strain of the postural control system and that a reduced postural sway amplitude during kneeling was related to an unusual body configuration rather than better postural performance.

Dust structures formed in exothermic chain plasma chemical processes initiated by pulsed gyrotron radiation in mixtures of metal and dielectric powders are studied. The composition of the powder mixture corresponds to the composition of the lunar regolith. Experiments at the energy of the gyrotron microwave pulse of 1–3 kJ and a pulse duration of 1.5–4 ms reveal an explosive process caused by the Coulomb repulsion of charged particles from the surface of the regolith into the reactor volume. The explosion is followed by the development of chain self-propagating high-temperature synthesis reactions. During these reactions lasting for tens of seconds, the suspension of dust particles rises tens of centimeters above the powder surface. The energy release is more than two orders of magnitude higher than the energy of initiation of a chain reaction. Regolith spheroids with diameters from 1 to 1000 µm precipitate on the side surfaces of the reactor. An analogy of the possible contribution of the Coulomb repulsion between charged particles and plasma exothermic processes to the dispersion of regolith dust when the Moon surface is bombarded by micrometeorites is considered.

The method of remote neutron and gamma spectrometry of bodies in the solar system (the Moon, Mars, and Mercury) has been used for several decades to estimate the nuclear composition of these objects and the hydrogen abundance in their subsurface layers. Proportional gas counters based on helium-3 (3He), which have the maximum efficiency of detecting thermal and epithermal neutrons, are used most often for measuring the low-energy neutron component. However, the data from LEND and FREND space experiments with large-volume and high-pressure helium counters revealed the noise contamination of lower channels of the neutron component due to the sensitivity of such counters to cosmic charged particles. The model of a promising neutron detector with anticoincidence protection, which is free from this drawback, is presented below.

Photo-controlled or photo-regulated molecules, especially biologically active and operating in physiological conditions, are in steady demand. Herein, furocoumaric and furocoumarinic acids being (Z/E)-isomers relative to each other were obtained in two stages starting from psoralen: the alkaline solvolysis of psoralen led to furocoumaric acid, which was further Z → E photoisomerized (365 nm) to furocoumarinic acid. The kinetics of Z → E photoisomerization was monitored by HPLC and UV-vis spectrophotometry. Photophysical characteristics in the aqueous phase for both acids, as well as the reversibility of (Z/E) photoisomerization process, were also assessed. Furocoumarinic acid was found to be visibly fluorescent at pH 2.0–12.0, with the maxima of fluorescence emission spectra being pH-dependent. The reverse E → Z photoisomerization predicted by quantum chemistry calculations as energetically favorable for the monoanionic form of furocoumarinic acid was proved in the experiment while being complicated by pyrone ring closure back to psoralen in acidic and neutral conditions. The preparative synthesis of furocoumarinic acid outlined in this work is particularly valuable in view of a wide range of pharmacological effects previously predicted for this compound.

Deep-sea hemichordates Torquaratoridae gen. sp. reach high abundance up to 12 spec. m

Nudibranch mollusks (Gastropoda: Heterobranchia) are widely known for their ability to incorporate some active biochemical compounds of their prey, or even organelles and symbionts of the prey, which assured biological success of this group. At the same time, the process of nematocysts obtaining and incorporation into specific structures called cnidosacs by cladobranch mollusks remain poorly studied. This highlights a necessity of additional ultrastructural studies of cnidosac and adjacent organs in various aeolid mollusks using modern microscopic methods as they may provide new insight into the cnidosac diversity and fine-scale dynamics of nematocysts sequestration process. The present study is focused on the general and fine structure of the cnidosac area in cladobranch Aeolidia papillosa (Aeolidiidae). Specific goals of our study were to provide a detailed description of histological and ultrafine structure of epidermis, upper parts of the digestive glands and the cnidosac, its innervation and proliferation using standard histological techniques, confocal laser scanning microscopy (CLSM) and transmission electron microscopy. Our results clearly demonstrated that A. papillosa cnidosac is a much more complex structure, than it was thought, especially compared with simple cnidosacs found in flabellinids and facelinids. Using CLSM for functional morphological analysis provides a better resolution in visualization of structural elements within a cnidosac compared with traditional histological techniques. We revealed the presence of two cell types in the cnidophage zone: cnidophages and interstitial cells, which differ in ultrastructure and function. Our results also document the presence of a specific cnidopore zone, lined with differentiated cuboid epithelium bearing long microvilli, which likely provides a unidirectional flow of nematocysts during kleptocnides extrusion. For the first time, occurrence of vacuoles containing protective chitinous spindles in the cnidosac epithelium was shown.

We present a study of the solar-cycle variations of >80 MeV proton flux intensities in the lower edge of the inner radiation belt, based on the measurements of the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) mission. The analyzed data sample covers an ~8 year interval from 2006 July to 2014 September, thus spanning from the decaying phase of the 23rd solar cycle to the maximum of the 24th cycle. We explored the intensity temporal variations as a function of drift shell and proton energy, also providing an explicit investigation of the solar-modulation effects at different equatorial pitch angles. PAMELA observations offer new important constraints for the modeling of low-altitude particle radiation environment at the highest trapping energies., accepted for publication in the Astrophysical Journal Letters

We present a study of the east-west anisotropy of trapped-proton fluxes in low-Earth orbit based on the measurements of the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) experiment. The differential intensities of eastward- and westward-traveling protons detected in the South Atlantic Anomaly region were estimated as a function of equatorial pitch angle and drift shell, for six energy bins between 80 MeV and 2 GeV. We found that, as a consequence of the strong atmospheric gradient coupled with the large gyroradius in this energy range, the intensities of eastward fluxes exceed those of westward fluxes by a factor of ∼10-20. However, the reported directional asymmetry also depends on the sign of the local flux gradient, resulting in more intense westward fluxes beyond the radial distances where the inner belt peaks. PAMELA observations can be used to improve the description of the near-Earth radiation environment at lowest altitudes and highest trapping energies, where current theoretical and empirical models are affected by the largest uncertainties.

Background: Despite the introduction of direct oral anticoagulants, the search for new oral anticoagulants remains an urgent task. Objective: By using docking and scoring, based on physical methods, simple chemical rules, methods of synthesis, and activity measurement, develop new low-molecular-weight inhibitors of factor Xa, which are potential anticoagulants. Method: The development of leads was based on chemical synthesis and structure-based drug design methods. The basic idea was to combine the two approaches: one based on predictive modeling and the other based on the experimental data. Results: In this study, we developed some nanomolar leads. Further chemical modification improved the inhibition constant by more than one order. Discussion: The method proposed in this paper, as well as other methods, includes virtual screening, chemical synthesis, and activity measurement. However, the most time–consuming process in this method (chemical synthesis) was simplified, and the cost was reduced to the extent that was allowed; a very simple chemical reaction was chosen, i.e., the formation of an amide bond. Conclusion: In this work, we demonstrated how using simple chemical rules based on the structurebased drug design, substances with a nanomolar concentration of activity can be developed.

Psoralens are medicinal photosensitizing furocoumarins which are used in photochemotherapy and photoimmunotherapy of dermatoses. Psoralen photooxidation products may be involved in therapeutic effects, but the possible mechanisms of their action remain unclear. The study was aimed to assess the prospective pharmacological effects and mechanisms of activity for six previously identified ortho–hydroxyformyl-containing psoralen photooxidation products and their cycloadducts with aminothiols, as well as for structurally similar compounds (furocoumaric acid and tucaresol). Chemoinformatic analysis of the prospective pharmacological effects and mechanisms of action of these compounds was performed using the PASS and PharmaExpert software. The predicted pharmacological effects partially confirmed by previous studies highlight the possible involvement of psoralen photooxidation products in the effects of PUVA therapy or photopheresis during the course of dermatoses and proliferative disorders treatment. A broad spectrum of pharmacological effects found for furocoumaric acid and cycloadducts of coumarinic and benzofuranic photoproducts of psoralen with cysteine and homocysteine appoints new directions of research relating to therapeutic use of psoralens.

The excretory system ultrastructure and immunocytochemistry have been investigated in the plerocercoid Pyramicocephalus phocarum. It has been shown that P. phocarum has independent terminal cells, cyrtocytes. The entire canal system is a single undivided syncytium, which includes nephridial funnels of the terminal tubules, and peripheral and central canals. The nephridial funnel and cyrtocyte form a filtration complex of the protonephridial type. In the caudal region, several peripheral canals open into a deep fold of the tegument, the urinary bladder. The excretory pores are separated from the tegument by annular septate desmosomes. There are no cell junctions inside the excretory system. The presence of the F-actin ring and the expression of non-synaptic serotonin in the collar area have been detected in cyrtocytes by immunocytochemistry methods.

Siboglinids are a characteristic feature of reducing environments. More than 75% of all siboglinids were found in the Sea of Okhotsk at a depth of less than 400 m, while some species are known to inhabit the abyssal depth in other regions. Among the six species of siboglinids encountered in the Sea of Okhotsk, only two are widespread: Siboglinum caulleryi and Oligobrachia dogieli. A significant number of all findings belong to the area where, according to geological data, the methane concentration varies between 0.22 and 4.46*109 nmol/kg. There is a vast territory in the central part of the Sea of Okhotsk that is not inhabited by siboglinids and is characterized by minimum methane concentration values. Thus, data on the Sea of Okhotsk indicate that siboglinids are related to sites of methane seepage.

Permafrost areas are characterized by the presence of adverse natural factors that affect production and all other areas of human activity. However, the need for mining in such areas has led to the emergence of large cities with developed social and transport infrastructure, such as Murmansk, Norilsk, and Yakutsk. The tasks of transport services to the population in such cities are traditionally assigned to public transport, and, traditionally, the issue of organizing the tram traffic in such regions is raised. The chapter analyzes the influence of climatic features of permafrost areas on the organization of tram traffic and the construction of tram tracks. The requirements for the maintenance of tram tracks in the winter period in conditions of high snowfall and high intensity of snowfall and blizzards are described. The possibility of organizing the route of the tram tracks with the optimal transverse profile of the embankment is considered: its height and provision of its aerodynamic streamlining to avoid the formation of vortex zones.

Precise time-dependent measurements of the Z = 2 component in the cosmic radiation provide crucial information about the propagation of charged particles through the heliosphere. The PAMELA experiment, with its long flight duration (2006 June 15-2016 January 23) and the low energy threshold (80 MeV/n) is an ideal detector for cosmic-ray solar modulation studies. In this paper, the helium nuclei spectra measured by the PAMELA instrument from 2006 July to 2009 December over a Carrington rotation time basis are presented. A state-of-the-art three-dimensional model for cosmic-ray propagation inside the heliosphere was used to interpret the time-dependent measured fluxes. Proton-to-helium flux ratio time profiles at various rigidities are also presented in order to study any features that could result from the different masses and local interstellar spectra shapes.

形態: カラー図版あり, Physical characteristics: Original contains color illustrations, Accepted: 2022-02-09, 資料番号: PA2220041000

Studies of hydrogen deposition in the shallow Martian subsurface have been conducted by two neutron and one gamma-ray detectors in the past and provided global hydrogen maps (Boynton et al., 2002; Feldman et al., 2002; Mitrofanov et al., 2002). It is known from these maps that hydrogen is most abundant in the polar permafrost areas compared to the equatorial band where frozen water is not stable on the surface. However, the spatial resolution of hundreds of kilometres typical for these maps does not allow for detection of local hydrogen-rich features that can be associated with geological structures. FREND neutron telescope (Mitrofanov et al., 2018) onboard ExoMars TGO (Vago et al., 2015) is capable of a much better spatial resolution for mapping neutron emission of Mars. In this Report we present the analysis of the most intriguing local area of highly suppressed neutron emission in the vicinity of the Martian equator, which coincides with Candor Chaos in the central area of Valles Marineris, thought to be promising for testing water ice (Gourronc et al., 2014). Provided such suppression would be interpreted as the evidence for very high content of hydrogen in the soil, the mean water equivalent hydrogen value in the local suppression area should be as large as 40.3 wt%. This finding is thought to be uncommon for equatorial regions, but is probably associated with particular geomorphological conditions inside Valles Marineris.

Lineus species are the most abundant nemerteans that inhabit boreal regions of the Atlantic and Arctic Oceans and are the focus of many zoological studies. However, its taxonomy and species composition in Arctic areas remain poorly known. In this study, we performed an updated genetic analysis of nemerteans from the “Lineus ruber–viridis” complex, clarified its species composition in the White Sea, and identified their diagnostic features. Molecular data based on mtDNA analysis indicate the presence of L. ruber, L. viridis, and L. clandestinus in the studied area, which was consistent with morphological data. Short descriptions of external morphological features are provided. External morphologies of European and White Sea Lineus species have some peculiarities: L. clandestinus from the White Sea lacks the iridescent ventral fold, and L. ruber has an unusual “green” form. The recovered genetic structure differed among the three species, which may have resulted from different dispersal scenarios during the last glacial maximum. The low level of nucleotide diversity combined with the typical star-like structure of the network indicated that an ancestral northern L. ruber population underwent a bottleneck event in the recent historical past.

Controllable morphing is still a challenge in the field of 4D printing. In this paper, a novel 4D printing technology of composites with embedded continuous fibers is introduced, and the bilayer prepared by this technology can realize programmable deformation with a high deformation accuracy. The deformation of the composite structure is caused by the difference of coefficients of thermal expansion (CTEs) between continuous fibers and flexible matrix. The angle between the intersecting fibers determines the size of the principal curvature, while the bisector of the angle of the fibers determines the direction of the principal curvature. Utilizing this rule, deformation of arbitrary deployable surface can be realized by designing the fiber trajectories. The high control accuracy of fiber orientation leads to a high deformation accuracy of 4D printed structure. The error between the theoretical value and the experimental value of the conical surface curvature is not more than 6%. In addition, the smart composite structure with the ability of temperature response and self-actuated deforming composite structure have also been prepared by this 4D printing process. Keywords: 4D printing, Continuous fibers, Composites, Programmable morphing

In the period from 2006 to 2016, experiments based on the use of the PAMELA and ARINA spectrometers and aimed at detecting cosmic rays were performed on board the RESURS-DK1 satellite. Although the main goal of these experiments was to study the galactic component of cosmic rays, the instruments in question also detected, over a broad energy range, solar particles accelerated in powerful explosive processes on the Sun (solar flares). A list of solar events in which the PAMELA and ARINA spectrometers detected, in various years of their operation, an increase in the intensities of fluxes of solar protons whose energies were above 45 MeV is presented among other things.

The chemical potential of a component in a system is customarily defined as the Gibbs energy of transferring of one mole of this component from a unary reservoir to the system at constant temperatu...

This paper summarizes data on new approaches to the detection, identification, and quantitative determination of manifestations of spatial inhomogeneities in the chemical composition and structure of mixtures of inorganic solid phases by a standardless differential dissolution (DD) stoichiographic method. We present mathematical modeling results for DD processes in different models for mixtures of solid phases. Based on the modeling results, we formulate rules of stoichiographic calculations for DD results, which are confirmed in identifying manifestations of spatial inhomogeneities in the phase composition of real systems, including fanlike separation of phase mixtures, without their selective separation.

The Mars Science Laboratory Dynamic Albedo of Neutrons (DAN) experiment measures the martian neutron leakage flux in order to estimate the amount of water equivalent hydrogen present in the shallow regolith. When DAN is operating in passive mode, it is sensitive to neutrons produced through the interactions of galactic cosmic rays (GCR) with the regolith and atmosphere and neutrons produced by the rover’s Multi-Mission Radioisotope Thermoelectric Generator (MMRTG). During the mission, DAN passive mode data were collected over the full diurnal cycle at the locations known as Rocknest (sols 60–100) and John Klein (sols 166–272). A weak, but unexpected, diurnal variation was observed in the neutron count rates reported at these locations. We investigate different hypotheses that could be causing these observed variations. These hypotheses are variations in subsurface temperature, atmospheric pressure, the exchange of water vapor between the atmosphere and regolith, and instrumental effects on the neutron count rates. Our investigation suggests the most likely factors contributing to the observed diurnal variations in DAN passive data are instrumental effects and time-variable preferential shielding of alpha particles, with other environmental effects only having small contributions.

The article examines the social and political situation in Germany after the so called “migration crisis”. In the author’s view, the very term “migration crisis” should not be taken for granted. First, the whole economic and political system undergoes a crisis; migration flows are the consequence but not the cause of this. Second, the situation around migration has been described in the academic literature in terms of crisis for some decades. Third, the framing of the 2015 events in terms of “crisis” diverts attention from the European politicians’ miscalculations in the early 2010s. The author claims that the German chancellor’s decision to allow entrance for a significant number of forced migrants in 2015-2016 was motivated not only by humanitarian reasons. Pragmatic reasons played a great part, too. It was assumed that the benefits of the inflow of an able-bodied population would exceed the costs in the long run. Despite all the frictions in the ruling elites, there is a basic consensus that the integration of newcomers will boost economy. Moreover, the “open door” policy towards refugees was of a short-term nature. In fact, it had been curtailed by the Spring 2016. Various measures had been taken to reduce undesirable immigration: the agreement with Turkey, the adding of Kosovo and a number of North African states plus Afghanistan to the list of “secure countries”, facilitating of deportation procedures, the “Malta agreement” with Tripoli, negotiations with African governments on financial assistance in exchange for efforts to curb immigration, etc. Further, the author turns to the attitudes in the civil society toward immigrants and immigrants’ integration and shows that the “proimmigrant” attitudes should not be underestimated. The majority of ordinary Germans are ready to incorporate the newcomers. At the same time, there is a significant population segment, especially in the East, which feels socially excluded. These people have been main voters of the “Alternative for Germany” (AfD) party. The author argues that the very presence of the Far Right in the Bundestag will have impact both on politics and public debate. It will make the decision-making concerning the immigrants’ integration more difficult, although the AfD faction is too small to block such decisions. The Far Right could also contribute to the transformation of public discourse: due to their activity in the parliament and in mass media the ultra-nationalist rhetoric will stop being a taboo.

Studies of echinoid microscopic anatomy over the last two centuries have created a number of inaccuracies and mistakes that have accumulated in the descriptions of the intricate organization of the coelomic system of Echinoidea. To clarify the situation, we reconstructed the axial complex and radial complex of the echinoid Strongylocentrotus pallidus. The water ring is located between the perivisceral coelom and the perioral coelom. The oral haemal ring lies between the coelothelia of the water-vascular, perivisceral, and perioral rings. The axial part of the axial organ communicates with the oral haemal ring in interradius CD, but the axial coelom does not form the axocoelomic perihaemal ring. The ventral intestinal haemal vessel originates from the oral haemal ring in radius A, and then branches into a network of capillaries, from which the dorsal intestinal vessel starts. The pericardial coelom envelopes the pericardial part of the axial organ, the lacunae of which communicate with the haemocoel of the body wall and with the axial part of the axial organ. The genital haemal ring and the dorsal intestinal vessel communicate with the axial organ. The genital coelom passes in the CD interradius on the side opposite to the hindgut. There is a somatocoelomic perihaemal ring, which sends a pair of coelomic outgrowths into each radius, accompanied by a radial haemal vessel in the oral part. The mistakes and inaccuracies of early descriptions of the echinoid axial complex are listed. The axial complex and associated structures of sea urchins are compared with other eleutherozoans.