Coherent Unit Research Articles

Impact of genome architecture on the functional activation and repression of Hox regulatory landscapes

BackgroundThe spatial organization of the mammalian genome relies upon the formation of chromatin domains of various scales. At the level of gene regulation in cis, collections of enhancer sequences define large regulatory landscapes that usually match with the presence of topologically associating domains (TADs). These domains often contain ranges of enhancers displaying similar or related tissue specificity, suggesting that in some cases, such domains may act as coherent regulatory units, with a global on or off state. By using the HoxD gene cluster, which specifies the topology of the developing limbs via highly orchestrated regulation of gene expression, as a paradigm, we investigated how the arrangement of regulatory domains determines their activity and function.ResultsProximal and distal cells in the developing limb express different levels of Hoxd genes, regulated by flanking 3′ and 5′ TADs, respectively. We characterized the effect of large genomic rearrangements affecting these two TADs, including their fusion into a single chromatin domain. We show that, within a single hybrid TAD, the activation of both proximal and distal limb enhancers globally occurred as when both TADs are intact. However, the activity of the 3′ TAD in distal cells is generally increased in the fused TAD, when compared to wild type where it is silenced. Also, target gene activity in distal cells depends on whether or not these genes had previously responded to proximal enhancers, which determines the presence or absence of H3K27me3 marks. We also show that the polycomb repressive complex 2 is mainly recruited at the Hox gene cluster and can extend its coverage to far-cis regulatory sequences as long as confined to the neighboring TAD structure.ConclusionsWe conclude that antagonistic limb proximal and distal enhancers can exert their specific effects when positioned into the same TAD and in the absence of their genuine target genes. We also conclude that removing these target genes reduced the coverage of a regulatory landscape by chromatin marks associated with silencing, which correlates with its prolonged activity in time.

Advancing land-sea integration for ecologically meaningful coastal conservation and management

Coasts are among our most valuable natural assets but are under intense pressure from human use and climate change. Despite this, coasts – as a coherent ecological unit – have been poorly included in conservation plans, largely because they are inadequately delineated. There are usually gaps and overlaps at the edges of the separate terrestrial-, estuarine- and marine-realm maps, and often no clarity on which specific coastal boundary (e.g., high-water mark) was used, other than vaguely, ‘the coastline’. This particularly compromises conservation and management of ecotonal, intertidal ecosystems along realm-map seams because they are poorly defined and mapped. Therefore, a key step in advancing coastal conservation, assessment, planning and management is to generate a fine-scale ecosystem-type map that is seamless across realms. We undertook this for South Africa, aiming to delineate the ecotone into ecologically meaningful zones comprising structurally and functionally appropriate ecosystem types. We defined and mapped (at <1:3000) the ‘seashore’ as the land-sea interface between the dune scrub-thicket break and the back of the surf zone. The seashore is divided at the dune base into a landward ‘backshore’ and seaward ‘shore’, with the inherent dynamic variability included in the boundary delineation and constituent ecosystem types. Estuaries were also embedded into the map. Finally, we created rules for including adjacent terrestrial and marine ecosystem types in an ecologically determined coastal zone. We describe what tools this seashore integration and coastal delineation has unlocked, and how this places South Africa in a strong position to manage and conserve its coast.

Petrology and Geochemistry of Serpentinites Associated with the Ultra-High Pressure Lago di Cignana Unit (Italian Western Alps)

AbstractIn the Western Alps, the ophiolitic Zermatt–Saas Zone (ZSZ) and the Lago di Cignana Unit (LCU) record oceanic lithosphere subduction to high (540°C, 2·3GPa) and ultra-high pressure (600°C, 3·2GPa), respectively. The top of the Zermatt–Saas Zone in contact with the Lago di Cignana Unit consists of olivine + Ti-clinohumite-bearing serpentinites (the Cignana serpentinite) hosting olivine + Ti-clinohumite veins and dykelets of olivine + Ti-chondrodite + Ti-clinohumite. The composition of this serpentinite reveals a refertilized oceanic mantle peridotite protolith that became subsequently enriched in fluid-mobile elements (FME) during oceanic serpentinization. The olivine + Ti-clinohumite veins in the Cignana serpentinite display Rare Earth Element (REE) and FME compositions quite similar to the host-rock, which suggests closed-system dehydration of this serpentinite during subduction. The Ti-chondrodite-bearing dykelets are richer in REE and FME than the host-rock and the dehydration olivine + Ti-clinohumite veins: their Nd composition points to a mafic protolith, successively overprinted by oceanic metasomatism and by subduction zone recrystallization. These dykelets are comparable in composition to eclogites within the ultra-high pressure LCU that derive from subducted oceanic mafic crust. Different from the LCU, serpentinites from the core domains of the ZSZ display REE compositions indicating a depleted mantle protolith. The oceanic serpentinization of these rocks led to an increase in FME and to seawater-like Sr isotope compositions. The serpentinites sampled at increasing distance from the ultra-high pressure LCU reveal different mantle protoliths, still preserve an oceanic geochemical imprint and contain mafic dykelets affected by oceanic metasomatism. The subduction zone history of these rocks thus occurred under relatively closed system conditions, the only possible change during subduction being an enrichment in As and Sb recorded by the serpentinites closer to the crustal LCU. The ZSZ and Cignana serpentinites thus likely evolved in a slab setting and were weakly exposed to interaction with slab-derived fluids characteristic of plate interface settings. Our data suggest two possible scenarios for the evolution of the studied ZSZ and Cignana serpentinites. They are either part of a coherent ophiolite unit whose initial lithospheric mantle was variably affected by depletion and re-fertilization processes, or they belong to separate tectonic slices derived from two different oceanic mantle sections. In the Cignana serpentinite atop the ZSZ, the presence of Ti-chondrodite dykelets similar in composition to the LCU eclogites suggests these two domains were closely associated in the oceanic lithosphere and shared the same evolution to ultra-high pressure conditions during Alpine subduction.

Genetic homogenization of indigenous sheep breeds in Northwest Africa

Northwest-African sheep represent an ideal case-study for assessing the potential impact of genetic homogenization as a threat to the future of traditional breeds that are adapted to local conditions. We studied ten Algerian and Moroccan breeds of sheep, including three transboundary breeds, distributed over a large part of the Maghreb region, which represents a geographically and historically coherent unit. Our analysis of the dataset that involved carrying out Genome-wide SNP genotyping, revealed a high level of homogenization (ADMIXTURE, NetView, fineSTRUCTURE and IBD segments analyses), in such a way that some breeds from different origins appeared genetically undistinguished: by grouping the eight most admixed populations, we obtained a mean global FST value of 0.0024. The sPCA analysis revealed that the major part of Morocco and the Northern part of Algeria were affected by the phenomenon, including most of the breeds considered. Unsupervised cross-breeding with the popular Ouled-Djellal breed was identified as a proximate cause of this homogenization. The issue of transboundary breeds was investigated, and the Hamra breed in particular was examined via ROH fragments analysis. Genetic diversity was considered in the light of historical archives and anthropological works. All of these elements taken together suggest that homogenization as a factor affecting the Maghrebin sheep stock, has been particularly significant over the last few decades, although this process probably started much earlier. In particular, we have identified the policies set by the French administration during the colonial period of the region’s history as a causal factor that probably contributed significantly to this process. The genetic homogenization that we have observed calls into question the integrity of the farm animal genomic resources represented by these local breeds, whose conservation is of critical importance to the future of the livestock sector.

Classifying children: a historical perspective on testing and measurement*

ABSTRACTAt the end of the 19th century, children were increasingly seen as measurable and classifiable objects of study on which a scientific approach to education could be based. Two factors fed into the development of this approach: confidence in scientific methods and the expansion of national education systems. Thus, there emerged a confluence of power and science that led to the measurement and classification of children in the name of an efficiently organized social system. This merging of reason, science and efficiency in the goal of classifying children came at a time when the old unitary school system was being declared outdated and coherent teaching units through which scientific methods of learning could be applied were being developed.

Inhibitory Units: An Organizing Nidus for Feature-Selective SubNetworks in Area V1.

Neuronal circuits often display small-world network architecture characterized by neuronal cliques of dense local connectivity communicating with each other through a limited number of cells that participate in multiple cliques. The principles by which such cliques organize to encode information remain poorly understood. Similarly tuned pyramidal cells that preferentially target each other may form multicellular encoding units performing distinct computational tasks. The existence of such units can reflect upon both spontaneous and stimulus-driven population events.We applied two-photon calcium imaging to study spontaneous population bursts in layer 2/3 of area V1 in male C57BL/6 mice. To identify potential small-world cliques, we searched for pyramidal cells whose calcium events had a consistent temporal relationship with the events of local inhibitory interneurons. This was guided by the intuition that groups of neurons whose synchronous firing represents a temporally coherent computational unit should be inhibited together. Pyramidal members of these interneuron-centered clusters on average displayed stronger functional connectivity between each other than with nonmember pyramidal neurons. The structure of the clusters evolved during postnatal development: cluster size and overlap between clusters decreased with developmental maturation. Pyramidal neurons in a cluster showed higher than chance tuning function similarity between each other and with the linked interneuron. Thus, spontaneous population events in V1 are shaped by small-world subnetworks of pyramidal neurons that share functional properties and work as a coherent unit with a local interneuron. These interneuron-pyramidal cell partnerships may represent a fundamental neocortical unit of computation at the population level.SIGNIFICANCE STATEMENT Neuronal circuit in layer 2/3 of mouse area V1 possesses small-world network architecture, where cliques of densely interconnected neurons ("small worlds") communicate via restricted number of hub cells. We show that: (1) in mouse V1 individual small-world cliques preferably incorporate pyramidal neurons with similar visual feature tuning, and (2) ongoing population activity of such pyramidal neuron clique is temporally linked to the activity of the local interneuron sharing its feature tuning with the clique members. Functional grouping of similarly tuned interneurons and pyramidal cells into cliques may ensure that ensembles of functionally alike pyramidal cells recruited during perceptual tasks and spontaneous activity are also turned off together as a unit, with interneurons serving as organizers of linked pyramidal ensemble activity.

Early Neoproterozoic magmatism and the associated metamorphism in the Songnen Massif, NE China: Petrogenesis and tectonic implications

Zircon U–Pb dating and geochemistry data were collected for Neoproterozoic rocks in the Songnen Massif of NE China, with the aim of understanding the extent and nature of the Precambrian basement as well as the early stages of tectonic evolution history of the massif. The newly discovered Neoproterozoic magmatism can be subdivided into three stages: (1) 929–927 Ma quartz-syenitic and syenogranitic gneisses, (2) ∼895 Ma granitic gneisses, and (3) 871 Ma granitic pegmatites. Associated metamorphisms can also be subdivided into two stages, i.e., the 492 Ma and 546–530 Ma, suggesting that the study area underwent two stages of metamorphism during the late Pan-African. The petrographical and geochemical data indicate that the 929–927 Ma syenitic rocks most likely originated from enriched mantle sources, which were metasomatized by subducted sediments and underwent fractional crystallization during ascension, whereas the ca. 895 Ma granitic gneisses were generated by the partial melting of ancient mafic lower crustal material. Combined with our previous study, it is suggested that the ∼929–927 and 895 Ma magmatism were formed in a convergent margin related to compressive orogenesis, consistent with the evolution of the Rodinia supercontinent. Similar tectono-magmatic thermal events occurred within the Songnen and Jiamusi massifs, suggesting that they could be one coherent continental unit in Precambrian.

Foreign policy anarchy in multiparty coalitions: When junior parties take rogue decisions

How do disagreements within multiparty coalitions affect foreign policy, and how can junior parties exert their influence? These questions are of growing importance as new media increases domestic pressure on politicians to interject in international events, and as foreign affairs become more salient in domestic political contestation. Whereas prior research on foreign policy in multiparty coalitions focuses on the influence of junior parties over cabinet decisions, this article proposes a new theoretical concept of ‘rogue decisions’ to describe a distinct outcome of partisan disagreements. Rogue decisions are autonomous decisions by junior parties impacting foreign affairs, taken without cabinet coordination, that undermine their senior partners’ foreign policies. This resembles the ‘anarchy model’ of foreign policy previously attributed to less institutionalized systems. Having identified the necessary conditions that make rogue decisions possible, and the factors that increase their likelihood, the analysis is applied to cases in Britain and Israel. These represent polar opposite parliamentary systems, with Israel among the most proportional, where rogue decisions may be most expected, and Britain the most majoritarian, where they would be least expected. The identification of rogue decisions in contrasting parliamentary democracies challenges the assumption that cabinet is where foreign policy disagreements are managed, according to established decision-making rules. The article therefore prompts new thinking about the potential for junior parties to disrupt the foreign policy agendas of their senior partners, and challenges in new ways the assumption that states act as coherent units.

Two New Cryptic Bat Species within the Myotis nattereri Species Complex (Vespertilionidae, Chiroptera) from the Western Palaearctic

The Myotis nattereri species complex consists of an entangled group of Western Palaearctic bats characterized by fringing hairs along the rear edge of their uropatagium. Some members are relatively common while others are rare but all forms are morphologically very similar and their taxonomy is unresolved. Recent studies based on different molecular markers have shown that several major and unexpected lineages exist within this group of forest-dwelling bats. All the mitochondrial and nuclear markers tested to date have shown that these major lineages evolved as fully independent and coherent units and therefore each qualifies as distinct species. In the absence of proper morphological diagnosis, these lineages are informally referred to in the literature under different names. We explore here the external and craniodental variation of these lineages. Although all morphological measurements were overlapping between these lineages, we show that lineages can be completely discriminated in a multivariate morphometric space. Consistent with previous molecular reconstructions, these four major lineages represent two pairs of related species, each represented by a named species (Myotis nattereri s. str. and M. escalerai, respectively) and by unnamed forms (Myotis sp. A and Myotis sp. B, respectively). Herein we describe formally these two unnamed forms to clarify the taxonomy within this species complex. This new taxonomic view has important implication for the protection of these species, as three of the four taxa must now be considered as range-restricted species in need of conservation actions.

Active matter invasion.

Biologically active materials such as bacterial biofilms and eukaryotic cells thrive in confined micro-spaces. Here, we show through numerical simulations that confinement can serve as a mechanical guidance to achieve distinct modes of collective invasion when combined with growth dynamics and the intrinsic activity of biological materials. We assess the dynamics of the growing interface and classify these collective modes of invasion based on the activity of the constituent particles of the growing matter. While at small and moderate activities the active material grows as a coherent unit, we find that blobs of active material collectively detach from the cohort above a well-defined activity threshold. We further characterise the mechanical mechanisms underlying the crossovers between different modes of invasion and quantify their impact on the overall invasion speed.

FROM TEXT TO POLYCODE TEXT: SEMIOTIC CHANGES IN TEXT PRODUCTION

The article is devoted to the investigation of the linguistic notions of “text” and “polycode text”. The notion of a text has recently undergone a lot of changes in its interpretation. Nowadays, while defining of texts it has been offered to take into account different approaches to their study including not only grammatical, cognitive-semantic, communicative-pragmatic, but also semiotic and semiotic-cultural. The development of IT, the globalization, and changes in the ways of coding of information have increased the role of the semiotic approach in the interpretation of texts. Within the semiotic approach, today’s text is regarded as a set of monocode or polycode communicative resources which correlate with each other, form a complex integrative meaning and are addressed to recipients with a certain pragmatic purpose. It has been proposed to distinguish between monocode and polycode texts and to use the term “polycode” to accentuate the coexistence of two or more codes in one text space. A polycode text is regarded in the article as a coherent unit consisting of several semiotic codes: verbal, non-verbal (photographs, pictures, pictograms, ideograms, smiles, cartoons, tables), paraverbal (color, font, punctuation, layout, diacritical marks). Changes in the encoding of the information in texts and the emergence of new communicative resources have led to the necessity of the reviewing of text’s textuality. Polycoding and multimodality have been regarded in the research as standarts of textuality as well as cohesion, coherence, intentionality, acceptability, informativity, situationality and intertextuality.

Was Crustal Contamination Involved in the Formation of the Serpentine-Free Udachnaya-East Kimberlite? New Insights into Parental Melts, Liquidus Assemblage and Effects of Alteration

The petrologically unique Udachnaya-East kimberlite (Siberia, Russia) is characterised by unserpentinised and H2O-poor volcaniclastic and coherent units that contain fresh olivine, along with abundant alkali-rich carbonates, chlorides, sulphides and sulphates in the groundmass. These mineralogical and geochemical characteristics have led to two divergent that advocate different origins. It has been suggested that the unserpentinised units from Udachnaya-East are representative of pristine unaltered kimberlite. Conversely, the alkali-chlorine-sulphur enrichment has been attributed to interactions with crustal materials and, or, post-emplacement by brines. The mineralogical and geochemical features and the compositions of melt inclusions in unserpentinised and serpentinised Udachnaya-East kimberlite varieties are compared in this study. Both varieties of kimberlite have similar major, compatible and incompatible trace element concentrations and primitive mantle normalised trace element patterns, groundmass textures and silicate, oxide and sulphide mineral compositions. However, these two kimberlite varieties are distinguished by: (i) the presence of unaltered olivine, abundant Na-K-Cl-S-rich minerals (i.e. chlorides, Sbearing alkali-carbonates, sodalite) and the absence of H2O-rich phases (i.e. serpentine, iowaite (Mg4Fe3+(OH)8OCl•3(H2O)) in unserpentinised samples, and (ii) the absence of alkali- and chlorine-enriched phases in the groundmass and characteristic olivine alteration (i.e. replacement by serpentine and, or, iowaite) in serpentinised samples. In addition, melt inclusions hosted in olivine, monticellite, spinel and perovskite from unserpentinised and serpentinised kimberlite contain identical daughter phase assemblages that are dominated by alkali-carbonates, chlorides and sulphates/sulphides. This enrichment in alkalis, chlorine and sulphur in melt inclusions demonstrates that these elements were an intrinsic part of the parental magma. The paucity of alkali-carbonates and chlorides in the groundmass of serpentinised Udachnaya-East kimberlite is attributed to their instability and removal during post-emplacement alteration. All evidence previously used in support of crustal and brine of the Udachnaya-East kimberlite is thoroughly evaluated. We demonstrate that contamination models are inconsistent with petrographic, geochemical and melt inclusion data. Our combined data suggest that the Udachnaya-East kimberlite crystallised from an essentially H2O-poor, Si-Na-K-Cl-S-bearing carbonate-rich melt.

The early exhumation history of the Western TianshanUHPmetamorphic belt, China: New constraints from titanite U–Pb geochronology and thermobarometry

AbstractThe Chinese Western Tianshan terrane is a well‐known ultrahigh‐pressure (UHP) metamorphic belt that mainly consists of subducted oceanic crustal materials. While two uplift stages have been recognized, the early exhumation history has not been fully constrained. We conducted U–Th–Pb and trace element microanalysis of titanite as well as zircon fromUHPeclogites. Apart from several inclusions in garnet, three types of retrograde titanite have been identified based on their petrographic occurrences: (a) in matrix enclosing relict rutile; (b) as coarse‐grained coronas around garnet; and (c) in veins coexisting with epidote and/or apatite. The three types of titanite are homogeneous in chemical composition, low in Al, enriched in middle rare earth elements (REEs), and depleted in lightREEs and heavyREEs, suggesting their growth during retrograde decompression. Sensitive high‐resolution ion microprobe (SHRIMP) andLA‐ICP‐MSU–Pb dating of titanite from four samples, regardless of their textural occurrences, gave consistent ages ofc. 306 Ma. Phase equilibria modelling and Zr‐in‐titanite thermometry indicate that titanite replaced rutile at ~14 kbar and ~570°C, following a nearly isothermal decompression from theUHPpeak conditions of 30 kbar and 550–570°C.SHRIMPzircon U–Pb dating yields two age groups:c. 320 Ma andc. 305 Ma. The former is generally interpreted to be the age ofUHPstage. The latter, overlapping the titanite ages, represents the timing of titanite growth during exhumation. Thus, we estimate that the near‐isothermal exhumation from theUHPpeak conditions to the epidote–amphibolite facies retrogression (14 kbar) lastedc. 15 Ma, corresponding to an average exhumation rate of 3.4 ± 2.5 mm/yr (2σ). This exhumation rate lies within the range of oceanicLT‐HPbelts in the absence of continental subduction, suggesting a similar slab exhumation mechanism that operates in theUHPregime. The consistent retrograde metamorphic ages recorded by titanite from different localities, and the general agreement amongP–Tpaths in the adjacent area, suggest that theUHPunit of Western Tianshan metamorphic belt was likely exhumed as a coherent unit.

From Neandertals to modern humans: New data on the Uluzzian.

Having thrived in Eurasia for 350,000 years Neandertals disappeared from the record around 40,000–37,000 years ago, after modern humans entered Europe. It was a complex process of population interactions that included cultural exchanges and admixture between Neandertals and dispersing groups of modern humans. In Europe Neandertals are always associated with the Mousterian while the Aurignacian is associated with modern humans only. The onset of the Aurignacian is preceded by “transitional” industries which show some similarities with the Mousterian but also contain modern tool forms. Information on these industries is often incomplete or disputed and this is true of the Uluzzian. We present the results of taphonomic, typological and technological analyses of two Uluzzian sites, Grotta La Fabbrica (Tuscany) and the newly discovered site of Colle Rotondo (Latium). Comparisons with Castelcivita and Grotta del Cavallo show that the Uluzzian is a coherent cultural unit lasting about five millennia, replaced by the Protoaurignacian before the eruption of the Campanian Ignimbrite. The lack of skeletal remains at our two sites and the controversy surrounding the stratigraphic position of modern human teeth at Cavallo makes it difficult to reach agreement about authorship of the Uluzzian, for which alternative hypotheses have been proposed. Pending the discovery of DNA or further human remains, these hypotheses can only be evaluated by archaeological arguments, i.e. evidence of continuities and discontinuities between the Uluzzian and the preceding and succeeding culture units in Italy. However, in the context of “transitional” industries with disputed dates for the arrival of modern humans in Europe, and considering the case of the Châtelperronian, an Upper Paleolithic industry made by Neandertals, typo-technology used as an indicator of hominin authorship has limited predictive value. We corroborate previous suggestions that the Middle-to-Upper Paleolithic transition occurred as steps of rapid changes and geographically uneven rates of spread.

Mass transport deposits overprinted by contractional tectonics: a case study from the southern Apennines of Italy

AbstractMass transport deposits (MTDs), created by gravity-driven deformation of unlithified sediments, and tectonic mélanges produced by contractional deformation are characterized by a similar chaotic appearance. It follows that distinguishing structures formed by soft-sediment deformation during mass transport from those produced by contractional tectonics can be problematic. In fact, deformation occurring along detachment levels may completely obliterate the original sedimentary fabric. Although a number of advances have been made during recent decades, field criteria for discriminating structures within MTDs that are overprinted by later regional contraction are not readily applicable to all the exposed examples. We address some of these general issues through a detailed case study of the Monte Facito Formation in Italy. This Triassic unit was formed during the Africa–Europe continental separation and, since the Miocene, has been involved in contractional deformation during the construction of the Apennines. The Monte Facito Formation consists of a series of stratigraphically coherent units, separated by chaotic and often deformed intervals, whose origin has been previously attributed to either tectonic or sedimentary processes. An example is provided by a characteristic pebbly mudstone (or ‘paraconglomerate’) which has been interpreted as either a Triassic gravity-flow deposit, or alternatively, as a product of shearing along regional contractional detachments during the Miocene. This detailed field-based study allows us to recognize structures related to the depositional processes that created these chaotic intervals, and which can therefore be interpreted as MTDs. We also discriminate structures connected to later contractional tectonics that locally produced intense reworking of the MTDs.

Mapping road network communities for guiding disease surveillance and control strategies

Human mobility is increasing in its volume, speed and reach, leading to the movement and introduction of pathogens through infected travelers. An understanding of how areas are connected, the strength of these connections and how this translates into disease spread is valuable for planning surveillance and designing control and elimination strategies. While analyses have been undertaken to identify and map connectivity in global air, shipping and migration networks, such analyses have yet to be undertaken on the road networks that carry the vast majority of travellers in low and middle income settings. Here we present methods for identifying road connectivity communities, as well as mapping bridge areas between communities and key linkage routes. We apply these to Africa, and show how many highly-connected communities straddle national borders and when integrating malaria prevalence and population data as an example, the communities change, highlighting regions most strongly connected to areas of high burden. The approaches and results presented provide a flexible tool for supporting the design of disease surveillance and control strategies through mapping areas of high connectivity that form coherent units of intervention and key link routes between communities for targeting surveillance.

Spatial Characteristics and Duration of Extreme Wave Events around the English Coastline

This paper presents an analysis of the spatial characteristics and duration of extreme wave events around the English coast. There are five geographic regions which are affected as coherent units under extreme wave conditions, incorporating a sixth micro-wave climate region (western Lyme Bay). Characteristic storm tracks are associated with each region. Storms affecting the East region (North Sea coast) seldom impact other areas of England, whilst in contrast, storms affecting the Southwest or Northwest also have some impact on the Southeast. Average storm duration varies from 5 h in the Northwest to 14 h on the East coast north of the Humber. Storm duration exceeding 12.5 h in the Southwest and East (northern half) near guarantees that storm waves will span High Water, when it is of most significance for beach management operations. Storms along the East coast can be associated with anticyclonic conditions, as well as low pressure systems.

From collective oscillation to chimera state in a nonlocally coupled excitable system

Chimera states, which consist of coexisting domains of spatially coherent and incoherent dynamics, have been widely found in nonlocally coupled oscillatory systems. We demonstrate that chimera states can emerge from excitable systems under nonlocal coupling in which isolated units only allow for the equilibrium. We theoretically reveal that nonlocal coupling-induced collective oscillation is behind the occurrence of the chimera states. We find two different types of chimera states, phase-chimera states and excitability-chimera states, depending on the coupling strength. At weak coupling strength where collective oscillation is localized around the unstable homogeneous equilibrium, the chimera states are similar to the ones in nonlocally coupled phase oscillators. For the chimera states at strong coupling strength, the dynamics of both coherent units and incoherent units shift back and forth between low-amplitude oscillation induced by collective oscillation and high-amplitude oscillation induced by excitability of local units.

Mediterranean Bioconstructions Along the Italian Coast.

Marine bioconstructions are biodiversity-rich, three-dimensional biogenic structures, regulating key ecological functions of benthic ecosystems worldwide. Tropical coral reefs are outstanding for their beauty, diversity and complexity, but analogous types of bioconstructions are also present in temperate seas. The main bioconstructions in the Mediterranean Sea are represented by coralligenous formations, vermetid reefs, deep-sea cold-water corals, Lithophyllum byssoides trottoirs, coral banks formed by the shallow-water corals Cladocora caespitosa or Astroides calycularis, and sabellariid or serpulid worm reefs. Bioconstructions change the morphological and chemicophysical features of primary substrates and create new habitats for a large variety of organisms, playing pivotal roles in ecosystem functioning. In spite of their importance, Mediterranean bioconstructions have not received the same attention that tropical coral reefs have, and the knowledge of their biology, ecology and distribution is still fragmentary. All existing data about the spatial distribution of Italian bioconstructions have been collected, together with information about their growth patterns, dynamics and connectivity. The degradation of these habitats as a consequence of anthropogenic pressures (pollution, organic enrichment, fishery, coastal development, direct physical disturbance), climate change and the spread of invasive species was also investigated. The study of bioconstructions requires a holistic approach leading to a better understanding of their ecology and the application of more insightful management and conservation measures at basin scale, within ecologically coherent units based on connectivity: the cells of ecosystem functioning.

Evolution of Early Thule Material Culture: Cultural Transmission and Terrestrial Ecology

We investigate how evolution proceeds across multiple scales considering culture as species, hierarchically integrated systems, assemblages of many coherent units, and collections of ephemeral entities in order to examine the nature of Early Thule cultural evolution with reference to material culture and adaptive strategies. Results suggest that harpoon heads evolved via cultural transmission processes with little impact from terrestrial ecological context. In contrast, characteristics of architectural features, stone tool assemblages, and combined architecture and stone tools displayed evidence for significant effects of both cultural transmission and select measures of ecological context. There is no evidence that evolution was ‘evoked’ by ecological context alone.