The Circumpolar North has been changing rapidly within the last decades, and the socioeconomic systems of the Eurasian Arctic and Siberia in particular have displayed the most dramatic changes. Here, anthropogenic drivers of environmental change such as migration and industrialization are added to climate-induced changes in the natural environment such as permafrost thawing and increased frequency of extreme events. Understanding and adapting to both types of changes are important to local and indigenous peoples in the Arctic and for the wider global community due to transboundary connectivity. As local and indigenous peoples, decision-makers and scientists perceive changes and impacts differently and often fail to communicate efficiently to respond to changes adequately, we convened a meeting of the three groups in Salekhard in 2017. The outcomes of the meeting include perceptions of how the three groups each perceive the main issues affecting health and well-being and recommendations for working together better.
Over the last twenty years Russia has experienced significant fluctuations in sentiments regarding the prospects and urgency of relocating the Russian capital city. In this article, Vadim Rossman examines the public debates on this topic, which have involved important Russian politicians, intellectuals, and members of various expert communities. In these debates, one can recognize several distinct new visions of society that emerged in the post-Soviet period. This article provides an overview and a critique of these debates and suggests that they should be viewed in the context of nation building, the slow emergence of the nation that was historically suppressed under the weight of the imperial ambitions of Russian statehood. In the background of these debates, the concept of self-identity looms large. National capitals can serve as catalysts for nation building and an instrument of the nation as it constitutes and constructs itself.
The taxonomy of common northern nudibranch molluscs of the genus Dendronotus in the vast cold regions of Eurasia remains largely unknown. Abundant material collected in many localities from the Barents Sea, via the Arctic region, to the north-west Pacific was analysed for the first time. An integrated approach combining morphological and ontogenetic data with molecular four-gene (COI, 16S, H3, and 28S) analysis reveals seven species, including three previously undescribed. Dendronotus frondosus (Ascanius, 1774) and Dendronotus dalli Bergh, 1879 were commonly considered as amphiboreal species; however, according to this study they are restricted to the North Atlantic and the North Pacific, respectively. In the north-west Pacific two new species were discovered, Dendronotus kamchaticus sp. nov. and Dendronotus kalikal sp. nov., that are externally similar to D. frondosus, but that show significant distance according to molecular analysis and are considerably different in radular morphology. In the North Atlantic a new species Dendronotus niveus sp. nov., sibling to North Pacific D. dalli, is revealed. The separate status of North Atlantic Dendronotus lacteus (Thompson, 1840) is confirmed, including considerable range extension. The essential similarity of early ontogenetic stages of radular development common for species with disparate adult radular morphology (such as D. frondosus and D. dalli) is shown, and its importance for taxonomy is discussed.
We use data from the 2013–2014 Cluster Inner Magnetosphere Campaign, with its uniquely small spacecraft separations (less than or equal to electron inertia length, λe), to study multiscale magnetic structures in 14 substorm-related prolonged dipolarizations in the near-Earth magnetotail. Three time scales of dipolarization are identified: (i) a prolonged growth of the BZ component with duration ≤20 min; (ii) BZ pulses with durations ≤1 min during the BZ growth; and (iii) strong magnetic field gradients with durations ≤2 s during the dipolarization growth. The values of these gradients observed at electron scales are several dozen times larger than the corresponding values of magnetic gradients simultaneously detected at ion scales. These nonlinear features in magnetic field gradients denote the formation of intense and localized (approximately a few λe) current structures during the dipolarization and substorm current wedge formation. These observations highlight the importance of electron scale processes in the formation of a 3-D substorm current system.
The elastin binding protein (EBP), a spliced variant of lysosomal β-galactosidase, is the primary receptor of elastin peptides that have been linked to emphysema, aneurysm and cancer progression. The sequences recognized by EBP share the XGXXPG consensus pattern found in numerous matrix proteins, notably in elastin where the VGVAPG motif is repeated. To delineate the elastin binding site of human EBP, we built a homology model of this protein and docked VGVAPG on its surface. Analysis of this model suggested that Gln-97 and Asp-98 were required for interaction with VGVAPG because they contribute to the definition of a pocket thought to represent the elastin binding site of EBP. Additionally, we proposed that Leu-103, Arg-107, and Glu-137 were essential residues because they could interact with VGVAPG itself. Site-directed mutagenesis experiments at these key positions validated our model. This work therefore provides the first structural data concerning the interaction of the VGVAPG with its cognate receptor. The present structural data should now allow the development of EBP-specific antagonists.
One of the most intriguing and challenging questions in the interdisciplinary study of mental processes and underlying brain mechanisms is how language is related to thought. The question is by no means new. Scholars have attempted to unravel the relationship between language and thought since the early days of Western philosophy. Recent theories range from strictly modular accounts of linguistic processing to fully integrated theories, according to which linguistic processes strongly interact with more general cognitive mechanisms such as attention, memory, and action control. Unfortunately, theoretical exchange between proponents of these different views is often lacking. In part, this is due to the interdisciplinary nature of the question itself. As a result, researchers representing various disciplines often fail to engage in an exchange of theoretical views, research ideas, and methodological expertise. The present Frontiers' Special Topic provides a platform for such dialogue. It features contributions discussing the latest advances and challenges in the frontline research on language and cognition and attempts to provide a joint discussion forum for a wide range of researchers from the domains of cognitive psychology, neuroscience, and psycholinguistics, among others. These researchers follow different theoretical approaches and use different experimental methodologies. What unites them is their goal to understand the mechanisms underlying the interplay between linguistic and general cognitive processes. General cognitive mechanisms in linguistic communication do not only include retrieval and processing of linguistic information; they also rely upon constant updating and organizing of this linguistic information in relation with other, more general representations. Some existing theoretical models assume a tight interactive coupling between domain-general and domain-specific sources of information in the cognitive organization of the linguistic faculty. Domain-specific constraints may include, for example, grammatical as well as lexical and pragmatic knowledge. Domain-general constraints comprise processing limitations imposed by the cognitive mechanisms of memory, attention, learning, and social interaction. However, much of the existing research tends to focus on one or the other of the aforementioned areas, while integrative accounts are still rather sparse at present. The aim of this Special Topic of Frontiers in Cognition is therefore to bring together researchers who, within their respective research fields and by using different methodologies, represent integrative approaches to the study of language. Our Research Topic presents a collection of seventeen excellent articles that include original research, commentaries, opinions, and reviews. A number of papers in this Topic discuss neurophysiological and behavioral evidence about the interface between language, perception, and attention. Research discussed by Roelofs and Piai (2011)suggests that word planning does not always require full executive attention while specific attention deficits may contribute to impaired language performance. The results discussed by Roelofs and Piai (2011) demonstrate how gaze shifts can be linked to the process of phonological encoding with specific focus on word production automaticity. The article by Myachykov et al. (2012) presents evidence about the special role attention plays in determining the assignment of grammatical roles and the associated syntactic choice in visually situated sentence production. Papers by Huettig et al. (2012), Knoeferle et al. (2011), and Kaiser (2012) provide complementary evidence about the involvement of the language-cognition interface during sentence comprehension in visually situated contexts. The contribution by Shtyrov (2011) reports novel findings about rapid pre-attentive mapping of novel word forms, as evidenced by changes in the dynamics of brain responses within very short exposures. Finally, Hussey and Novick (2012) report intriguing evidence about the benefits of executive control training for grammatical processing in ambiguous contexts. The question of coordination between interlocutors during dialogue is raised in two articles. Gambi and Pickering (2011) used a novel interactive methodology in order to demonstrate that interlocutors constantly coordinate their sentences to represent their partner's knowledge. They then use these representations to build unfolding predictions, which they take into account when planning self-generated utterances. Similarly, Dale and colleagues (2011) use eye-movement synchronization between interlocutors as evidence for rapid approximation of actions in dialogue and the emergence of a single coordinated interactive system. Three papers in our Topic discuss embodied and grounded aspects of language processing. Lupyan (2012) addresses the question of the language-cognition interplay from the point of view of how language affects cognition and perception. In particular, Lupyan (2012) reviews evidence showing that performance on tasks that have been presumed to be non-verbal is rapidly modulated by language. Klemfuss et al. (2012) discuss effects of language on perception by critically reviewing evidence suggesting top-down influences of linguistic representations on visual feature detection. Their own research suggests that visual search is disrupted by the automatic activation of irrelevant linguistic representations. Another important aspect of the grounded view of language is the role played by perception and action systems in the organization of abstract knowledge. Scorolli et al. (2011) discuss the crucial role played by embodied theories of cognition in linguistic experience for abstract words. A number of papers in this Special Topic discuss architectural properties of the language-cognition interface. For example, Menenti et al. (2012) investigated how brain areas adapt to repetition of various sentence properties, thereby unraveling the neuronal infrastructure for the specific components of semantic encoding. Mashal and colleagues (2012) present a novel cortical network model for observation and imitation of speech. Their results show that the network models for observation and imitation comprise the same essential structure but differ in important features that reflect distinct connectivity patterns. Andric and Small (2012) contribute to the debate by discussing how the brain processes language and co-occurring gestures. Finally, Naylor et al. (2012) focus on cognitive and electrophysiological correlates of the bilingual Stroop effect by analysing corresponding ERP components in bilingual speakers. Their research shows, among other things that color words from both languages created response conflict and that the between-within language Stroop effect reflects complex brain activity with contributions from language both and color at different task points.
A hallmark of neurogenesis in vertebrates is the apical-basal fluctuation of radial glia nuclei. Such a phenomenon, called INM, has been known for decades and is closely associated with mitosis but still puzzles scientists. An impressive step in the molecular understanding of INM has recently been achieved by Tsai and coworkers. Using RNA interference associated with time-lapse imaging, these authors demonstrated a dual motor system that can push/pull the nuclei accordingly with the cell cycle stages.
In coastal seas and straits, the interaction of barotropic tidal currents with the continental shelf, seamounts or sills is often observed to generate large-amplitude, horizontally propagating internal solitary waves. Typically these waves occur in regions of variable bottom topography, with the consequence that they are often modeled by nonlinear evolution equations of the Korteweg-de Vries type with
variable coecients. We shall review how these models are used to describe the propagation, deformation and disintegration of internal solitary waves as they propagate over the continental shelf and slope.
The mutual influence of interregional migrations, the housing market, and the spatial transformation of the Moscow metropolitan area are studied empirically using the database of housing development projects and the depersonalized database of the residence addresses of buyers in the primary housing market. We consider the influence of natural rent, agglomeration economy, interregional inequality, and distance on the differentiation of the activity of residents of various Russian regions and cities in the primary housing market of the Moscow metropolitan area compared to their migration activity. The main characteristics of the extensive development of the Moscow metropolitan area are the prevalence of large greenfield residential district projects, urban sprawl in the near suburban zone, and the concentration of construction along transport corridors in the middle suburban zone. Selective influence of buyers from other regions on various zones of the Moscow metropolitan area owes to their orientation at the most affordable proposals in the primary market. The near suburban zone is the main gate into the Moscow metropolitan area for migrants, and construction in this zone is a major mechanism of restricting housing prices and maintaining economic incentives for large-scale migration to the Moscow region. Proceeding from the generalization of factors of the spatial transformation of the Moscow metropolitan area, a conceptual model of interaction between migration and urban spatial shifts is proposed.
Regulation of the formation and rewiring of neural circuits by neuropeptides may require coordinated production of these signaling molecules and their receptors that may be established at the transcriptional level. Here, we address this hypothesis by comparing absolute expression levels of opioid peptides with their receptors, the largest neuropeptide family, and by characterizing coexpression (transcriptionally coordinated) patterns of these genes. We demonstrated that expression patterns of opioid genes highly correlate within and across functionally and anatomically different areas. Opioid peptide genes, compared with their receptor genes, are transcribed at much greater absolute levels, which suggests formation of a neuropeptide cloud that covers the receptor-expressed circuits. Surprisingly, we found that both expression levels and the proportion of opioid receptors are strongly lateralized in the spinal cord, interregional coexpression patterns are side-specific, and intraregional coexpression profiles are affected differently by left- and right-side unilateral body injury. We propose that opioid genes are regulated as interconnected components of the same molecular system distributed between distinct anatomic regions. The striking feature of this system is its asymmetric coexpression patterns, which suggest side-specific regulation of selective neural circuits by opioid neurohormones.
The siloxane surface of uncharged clays is known to be hydrophobic, which is supported by strong experimental and theoretical evidence. For the siloxane surface of charged clays, like smectites, the picture is not as clear. We are aiming to clarify this issue by molecular simulations in which smectite surface hydrophobicity is quantified through the separate contribution of the surface itself, and the contribution due to the presence of charge-balancing cations on the surface. In order to explore systematically the effects of the total smectite charge and its distribution in the structure, a series of molecular dynamics (MD) simulations was performed for several models of dioctahedral smectites and compared with the results for uncharged pyrophyllite.
The largest difference between the simulation results for smectite models with naturally present surface counterions and the models where these ions were artificially removed from the surface, while maintaining the same total charge balance of the model, is in the shape of the water coverage. In the former case, full surface wetting is observed and a relatively flat water film is forming on the surface. Its irregularity and thickness is connected with number of ions on the surface. However, in all cases of smectite surfaces artificially devoid of ions, a water droplet is always formed and the wetting is incomplete. The contact angles of the water droplets on charged montmorillonites are very similar to that on uncharged pyrophyllite surface and range roughly between 110o and 90o. These angles are also affected by the distribution of the octahedral and tetrahedral substitutions in the structure and by their ratio. In the case of purely tetrahedral substitutions the contact angle on the bare smectite surface can be as low as ~60o, but still far from complete wetting.
The angular distributions of the H2O dipole vectors as a function of distance from the smectite surface show two preferred surface-oriented types of water molecules when counterions are present, and the total surface is highly hydrophilic. However, for surfaces devoid of ions, a population with dipole angles close to ~90o is dominating, and the smectite surfaces can be considered hydrophobic. It can be thus concluded that, independent of the structural charge, bare smectite surfaces by themselves are either hydrophobic or only moderately hydrophilic. Their experimentally observed highly hydrophilic character is almost entirely due to the charge balancing cations present on the surface.
Within the framework of model calculations the possibility of occurrence of the ion-acoustic oscillation instability in a plasma without current and particle fluxes, but with an anisotropic distribution function, which corresponds to heat flux is shown. The model distribution function was selected taking into account the medium conditions. The increment of ion-acoustic oscillation is investigated as functional of the distribution function parameters. The threshold condition for the anisotropic part of the distribution function, under which the build-up of ion-acoustic oscillation with the wave vector opposite to the heat flux begins is studied. The critical heat flux, which corresponds to the threshold of ion-acoustic instability, is determined. For the solar conditions, the critical heat flux proved to be close to the heat flux from the corona into the chromosphere on the boundary of the transition region. The estimations show that outside of active regions and even in active regions with weaker magnetic fields ion-acoustic turbulence can be responsible for the formation of the sharp temperature jump. The generalized Wiedemann-Franz law for a non-isothermic quasi-neutral plasma with developed ion-acoustic turbulence is discussed. This law determines the relationship between electrical and thermal conductivities in a plasma with well-developed ion-acoustic turbulence. The anomalously low thermal conductivity responsible to the formation of high temperature gradients in the zone of the temperature jump is explained. The results are used to explain some properties of stellar atmosphere transition regions.
Kalium ( http://kaliumdb.org/ ) is a manually curated database that accumulates data on potassium channel toxins purified from scorpion venom (KTx). This database is an open-access resource, and provides easy access to pages of other databases of interest, such as UniProt, PDB, NCBI Taxonomy Browser, and PubMed. General achievements of Kalium are a strict and easy regulation of KTx classification based on the unified nomenclature supported by researchers in the field, removal of peptides with partial sequence and entries supported by transcriptomic information only, classification of β-family toxins, and addition of a novel λ-family. Molecules presented in the database can be processed by the Clustal Omega server using a one-click option. Molecular masses of mature peptides are calculated and available activity data are compiled for all KTx. We believe that Kalium is not only of high interest to professional toxinologists, but also of general utility to the scientific community.
Database URL : http://kaliumdb.org/
In many areas of the Antarctic and Subantarctic, king crabs records are still fragmentary. New data on the distribution of Lithodidae in the Scotia Sea and the adjacent area of the south-west Atlantic and the south-east Pacific have been collected during exploratory pot fishing in the year 2010 and are also based on some earlier collections that are deposited in Russian museums. The occurrence of Lithodes macquariae off Peter I Island is confirmed. Lithodes confundens, Lithodes turkayi and Neolithodes diomedeae were found in abundance on the Northern Scotia Ridge at a depth of, respectively, 315–775, 315–1,410 and 840–1,300 m. Paralomis formosa was recorded for the first time on the shelf of the South Orkney Islands, which is the southernmost record of this species. New material and literature data demonstrate the existence of two discontinuous lithodid faunas: the Antarctic Pacific fauna that extends up to the western Antarctic Peninsula and the Magellanic—Scotia fauna. The origin of this faunal discontinuity is discussed. The molecular barcodes (subunitI of the mitochondrial cytochrome-oxidase gene—COI) data for N. diomedeae and L. turkayi are provided for the first time. COI gene tree suggests that two main Subantarctic/Antarctic lineages of Lithodes, i.e. a pair Lithodes santolla/L. confundens and L. turkayi (with possibly closely related Lithodes murrayi and L. macquariae) are phylogenetically distant from each other as well as with low-latitude Pacific and Atlantic species of this genus.
The investigation of dynamics of intense solitary wave groups of collinear surface waves is performed by means of numerical simulations of the Euler equations and laboratory experiments. The processes of solitary wave generation, reflection from a wall and collisions are considered. Steep solitary wave groups with characteristic steepness up to kAcr ~ 0.3 (where k is the dominant wavenumber, and Acr is the crest amplitude) are concerned. They approximately restore the structure after the interactions. In the course of the interaction with the wall and collisions the maximum amplitude of the wave crests is shown to enhance up to 2.5 times. A standing-wave-like structure occurs in the vicinity of the wall, with certain locations of nodes and antinodes regardless the particular phase of the reflecting wave group. A strong asymmetry of the maximal wave groups due to an anomalous set-up is shown in situations of collisions of solitons with different frequencies of the carrier. In some situations of head-on collisions the amplitude of the highest wave is larger than in overtaking collisions of the same solitons. The discovered effects in interactions of intense wave groups are important in the context of mechanisms and manifestations of oceanic rogue waves.
The nonlinear Schrödinger (NLS) equation describing the propagation of weakly rotational wave packets in an infinitely deep fluid in Lagrangian coordinates has been derived. The vorticity is assumed to be an arbitrary function of Lagrangian coordinates and quadratic in the small parameter proportional to the wave steepness. The vorticity effects manifest themselves in a shift of the wave number in the carrier wave and in variation in the coefficient multiplying the nonlinear term. In the case of vorticity dependence on the vertical Lagrangian coordinate only (Gouyon waves), the shift of the wave number and the respective coefficient are constant. When the vorticity is dependent on both Lagrangian coordinates, the shift of the wave number is horizontally inhomogeneous. There are special cases (e.g., Gerstner waves) in which the vorticity is proportional to the squared wave amplitude and nonlinearity disappears, thus making the equations for wave packet dynamics linear. It is shown that the NLS solution for weakly rotational waves in the Eulerian variables may be obtained from the Lagrangian solution by simply changing the horizontal coordinates.
Objective. Brain-computer interface (BCI) systems are known to be vulnerable to variabilities in background states of a user. Usually, no detailed information on these states is available even during the training stage. Thus there is a need in a method which is capable of taking background states into account in an unsupervised way. Approach. We propose a latent variable method that is based on a probabilistic model with a discrete latent variable. In order to estimate the model's parameters, we suggest to use the expectation maximization (EM) algorithm. The proposed method is aimed at assessing characteristics of background states without any corresponding data labeling. In the context of asynchronous motor imagery paradigm, we applied this method to the real data from twelve able-bodied subjects with open/closed eyes serving as background states. Main results. We found that the latent variable method improved classication of target states compared to the baseline method (in seven of twelve subjects). In addition, we found that our method was also capable of background states recognition (in six of twelve subjects). Signicance. Without any supervised information on background states, the latent variable method provides a way to improve classication in BCI by taking background states into account at the training stage and then by making decisions on target states weighted by posterior probabilities of background states at the prediction stage.
The issue of rogue wave lifetimes is addressed in this study, which helps to detail the general picture of this dangerous oceanic phenomenon. The direct numerical simulations of irregular wave ensembles are performed to obtain the complete accurate data on the rogue wave occurrence and evolution. Purely collinear wave systems, moderately crested, and short-crested sea states have been simulated by means of the high-order spectral method for the potential Euler equations. As rogue waves are transient and poorly reflect the physical eects, we join instant abnormally high waves in close locations and close time moments to new objects, rogue events, which helps to retrieve the abnormal occurrences more stably and more consistently from the physical point of view. The rogue event lifetime probability distributions are calculated based on the simulated wave data. They show the distinctive dierence between rough sea states with small directional bandwidth on one part, and small-amplitude sea states and short-crested states on the other part. The former support long-living rogue wave patterns (the corresponding probability distributions have heavy tails), though the latter possess exponential probability distributions of rogue event lifetimes and generally produce much shorter rogue wave events.
Bacterial cell wall is targeted by many antibiotics. Among them are lantibiotics, which realize their function via interaction with transmembrane lipid-II molecule — a chemically conserved part of the cell wall synthesis pathway. To investigate structural and dynamic properties of this molecule, we have performed a series of nearly microsecond-long molecular dynamics simulations (MD) of lipid-II and some of its analogs in zwitterionic single component and charged mixed model phospholipid bilayers (the reference and mimic of the bacterial plasmatic membrane, respectively). Extensive analysis revealed that lipid-II forms a unique “amphiphilic pattern” exclusively on the surface of the model bacterial membrane (and not in the reference bilayer). We hypothesize that conserved features of lipid-II along with characteristic modulation of the bacterial membrane provide a recognition spot for many lantibiotics. This putative recognition mechanism opens new opportunities for studies on lantibiotics action and design of novel armament against resistant bacterial strains.
Neuronal activity in the subthalamic nucleus (STN) of patients with Parkinson's disease (PD) is characterised by excessive neuronal synchronization, particularly in the beta frequency range. However, less is known about the temporal dynamics of neuronal oscillations in PD. In this respect long-range temporal correlations (LRTC) are of special interest as they quantify the neuronal dynamics on different timescales and have been shown to be relevant for optimal information processing in the brain. While the presence of LRTC has been demonstrated in cortical data, their existence in deep brain structures remains an open question. We investigated (i) whether LRTC are present in local field potentials (LFP) recorded bilaterally from the STN at wakeful rest in ten patients with PD after overnight withdrawal of levodopa (OFF) and (ii) whether LRTC can be modulated by levodopa treatment (ON). Detrended fluctuation analysis was utilised in order to quantify the temporal dynamics in the amplitude fluctuations of LFP oscillations. We demonstrated for the first time the presence of LRTC (extending up to 50 s) in the STN. Importantly, the ON state was characterised by significantly stronger LRTC than the OFF state, both in beta (13-35 Hz) and high-frequency (> 200 Hz) oscillations. The existence of LRTC in subcortical structures such as STN provides further evidence for their ubiquitous nature in the brain. The weaker LRTC in the OFF state might indicate limited information processing in the dopamine-depleted basal ganglia. The present results implicate LRTC as a potential biomarker of pathological neuronal processes in PD.
Modeling of tsunamis in glacial fjords prompts us to evaluate applicability of the crosssectionally averaged nonlinear shallow water equations to model propagation and runup of long waves in asymmetrical bays and also in fjords with two heads. We utilize the Tuck-Hwang transformation, initially introduced for the plane beaches and currently generalized for bays with arbitrary cross section, to transform the nonlinear governing equations into a linear equation. The solution of the linearized equation describing the runup at the shore line is computed by taking into account the incident wave at the toe of the last sloping segment. We verify our predictions against direct numerical simulation of the 2-D shallow water equations and show that our solution is valid both for bays with an asymmetric L-shaped cross section, and for fjords with two heads—bays with a W-shaped cross section