Horizontal Connections Research Articles

Influence of offshore oil and gas structures on seascape ecological connectivity.

Offshore platforms, subsea pipelines, wells and related fixed structures supporting the oil and gas (O&G) industry are prevalent in oceans across the globe, with many approaching the end of their operational life and requiring decommissioning. Although structures can possess high ecological diversity and productivity, information on how they interact with broader ecological processes remains unclear. Here, we review the current state of knowledge on the role of O&G infrastructure in maintaining, altering or enhancing ecological connectivity with natural marine habitats. There is a paucity of studies on the subject with only 33 papers specifically targeting connectivity and O&G structures, although other studies provide important related information. Evidence for O&G structures facilitating vertical and horizontal seascape connectivity exists for larvae and mobile adult invertebrates, fish and megafauna; including threatened and commercially important species. The degree to which these structures represent a beneficial or detrimental net impact remains unclear, is complex and ultimately needs more research to determine the extent to which natural connectivity networks are conserved, enhanced or disrupted. We discuss the potential impacts of different decommissioning approaches on seascape connectivity and identify, through expert elicitation, critical knowledge gaps that, if addressed, may further inform decision making for the life cycle of O&G infrastructure, with relevance for other industries (e.g. renewables). The most highly ranked critical knowledge gap was a need to understand how O&G structures modify and influence the movement patterns of mobile species and dispersal stages of sessile marine species. Understanding how different decommissioning options affect species survival and movement was also highly ranked, as was understanding the extent to which O&G structures contribute to extending species distributions by providing rest stops, foraging habitat, and stepping stones. These questions could be addressed with further dedicated studies of animal movement in relation to structures using telemetry, molecular techniques and movement models. Our review and these priority questions provide a roadmap for advancing research needed to support evidence‐based decision making for decommissioning O&G infrastructure.

Novel discrete diaphragm system of concrete high-rise modular buildings

Modular high-rises are attractive for metropolises, but few applications exist, partly due to the lack of knowledge about their lateral behaviors. Existing concrete modular high-rises usually adopt a time-consuming and labor-intensive cast-in-situ concrete layer on modules to satisfy the continuous rigid diaphragm assumption. This study aims to develop an innovative discrete diaphragm system for concrete modular high-rises without a cast-in-situ concrete layer. A private residential building in Hong Kong (HK) was selected as the case building, in which the novel horizontal and vertical connection designs were proposed. A simplified spring model considering in-plane axial and shear behaviors was proposed to simulate the horizontal connections. A three-dimensional finite element model of the case building with discrete diaphragms was established using the spring model. A parametric study was conducted to examine the influence of horizontal connections on the deflection and natural periods of the case building under the HK code-specified wind loads. A comparative study was conducted using five cases with different connection stiffness sets to systematically investigate the influence of horizontal connections on the structural responses of the case building under the wind loads. Results show that the discrete diaphragm system is feasible for concrete modular high-rises in HK. Effects of horizontal connections on the lateral behavior of concrete modular high-rises should be considered in the structural design when the discrete diaphragms are adopted. This study breaks through the continuous rigid diaphragm assumption and proves that appropriate flexible horizontal connections are a feasible option for concrete modular high-rises under wind loads.

Classical-Contextual Interactions in V1 May Rely on Dendritic Computations

A signature feature of the neocortex is the dense network of horizontal connections (HCs) through which pyramidal neurons (PNs) exchange “contextual” information. In primary visual cortex (V1), HCs are thought to facilitate boundary detection, a crucial operation for object recognition, but how HCs modulate PN responses to boundary cues within their classical receptive fields (CRF) remains unknown. We began by “asking” natural images, through a structured data collection and ground truth labeling process, what function a V1 cell should use to compute boundary probability from aligned edge cues within and outside its CRF. The “answer” was an asymmetric 2-D sigmoidal function, whose nonlinear form provides the first normative account for the “multiplicative” center-flanker interactions previously reported in V1 neurons (Kapadia et al., 1995, 2000; Polat et al., 1998). Using a detailed compartmental model, we then show that this boundary-detecting classical-contextual interaction function can be computed by NMDAR-dependent spatial synaptic interactions within PN dendrites – the site where classical and contextual inputs first converge in the cortex. In additional simulations, we show that local interneuron circuitry activated by HCs can powerfully leverage the nonlinear spatial computing capabilities of PN dendrites, providing the cortex with a highly flexible substrate for integration of classical and contextual information.

Delivering net zero

What comes next? The 2021 Glasgow Climate Pact rightly expressed “alarm and utmost concern” at the impacts of climate change that are already being felt around the world, following repeated instances of death and destruction brought by extreme heat, floods and wildfires.11 United Nations Framework Convention on Climate Change (2021) Glasgow Climate Pact, UNFCCC. https://unfccc.int/sites/default/files/resource/cma2021_L16_adv.pdf It explicitly recognised that further impacts will be much lower at a 1.5C temperature increase than at 2C, and it stated that this means almost halving global carbon dioxide emissions this decade and reaching net zero around mid-century. More needs to be done to close the considerable gap between the ambition to limit climate change and the promised emission reductions. Pledges made by countries in Glasgow on issues such as deforestation, electric vehicles and methane need to be translated into real policy and action, accountability mechanisms need to be strengthened, and international climate finance needs to be bolstered. Nevertheless, a clear commitment to a global net-zero future has been made by global governments, mirrored throughout much of the private sector, and the principal challenge now is one of delivery on an accelerated timeframe. “This is both unimaginably daunting and eminently doable” “such investment must be fairly distributed and aligned to a broader strategy to deliver a just transition” “A critical part of the institutional infrastructure is ensuring horizontal and vertical connectivity in decision-making across local and national government” “emissions reduction commitments … remain woefully insufficient to limit a temperature rise to 1.5C” With the alarm bell still ringing from Glasgow, the single most important thing is that pledges are translated into accelerated whole-economy action so that this vision and the ambition of net zero rapidly become a global reality. Prof Emily Shuckburgh is Director of Cambridge Zero, the University of Cambridge's major climate change initiative. She is also Professor of Environmental Data Science at the Department of Computer Science and Technology and leads the UKRI Centre for Doctoral Training on the Application of AI to the study of Environmental Risks (AI4ER).

Seismic performance of superimposed RC shear walls with concealed bracings using different horizontal connections

To enrich the horizontal connection method and to further study the seismic performance of superimposed RC shear walls with concealed bracings (SRCBSWs) using different horizontal connections, three specimens including SRCBSW with horizontal connection by steel plate bolt kit (SPBK), SRCBSW with horizontal connection by U-ring buckle insert (URBI) and cast-in-place shear wall with concealed bracings were tested under quasi-static loading test. Test results indicated that SRCBSWs exhibited the seismic performance close to that of cast-in-place specimen. The horizontal connection of URBI not only enabled achieve the goal of equivalent cast-in-place connection, but had a beneficial effect on the energy consumption. Due to the fact that the steel plates of SPBKs slipped relative to the contact concrete, the horizontal connection by SPBK was not conducive to energy dissipation and stiffness degradation of the wall, while the load-bearing capacity and deformation characteristic could be enhanced due to the cooperative work of steel plates and concrete in later loading. Finite element analysis of SRCBSWs by Abaqus was conducted based on the proposed modelling techniques, and the reasonable accuracy of the numerical method was verified. The parametric analysis results showed that the axial load ratio, volumetric ratio of the X-shaped steel plate bracings and longitudinal reinforcement ratio in hidden column had obvious effect on the load-bearing capacity and elastic stiffness of SRCBSWs. Taking displacement ductility into account, the axial load ratio of SRCBSWs should be reasonably restricted in practice. Moreover, appropriate thickness of steel plates in SPBKs should be determined according to actual demand, but at least one set of SPBK needed to be arranged in the middle of the wall along the height direction when conducting the layout of SPBK. Besides, the inserted reinforcement ratio in URBI could be reinforced in accordance with the constructional requirements.

Sedimentary characteristics and sand-body distributions in the Lower Permian He 8 Member, Ordos Basin, China

The Lower Permian He 8 Member (P1h8) in the Ordos Basin is a typical producing zone of tight lithologic gas reservoirs. Analyses of sedimentary characteristics, electrofacies, and sand-body distributions of P1h8, conducted on modern fluvial deposits, outcrops, cores, and well logs, revealed that braided rivers that developed in the Lower P1h8 and Upper P1h8 are characterized by meandering river. Within these fluvial deposits, the procedure consists of analyzing high-resolution sequence stratigraphy and sedimentary dynamics defined from calibrated logging curve signatures and depositional studies. According to modern and ancient fluvial deposits, we have developed a process-based sedimentary conceptual model for interpreting and predicting the distribution and geometries of sand bodies in braided and meandering deposits. The main sand body of the braided river system was bars and channel fill deposits. The braided river sand bodies are distributed over multiple vertical superimpositions and overlapping horizontal connections. The meandering river sand bodies are mainly point-bar deposits, which are bead-shaped and exhibit scattered development in the vertical direction. This comparison indicates that there were significant differences between braided and meandering deposystems. The sand bodies in the Lower P1h8 were multidirectionally connected and primarily distributed in a stacked pattern. In contrast, the sand bodies in the Upper P1h8 were distributed in an isolated manner, and fine grains (mud and silt) were deposited between the sand bodies with poor connectivity. We interpreted the fluvial deposits that control the distributions of the sand body of the He8 Member in the eastern Sulige gas field and constructed a corresponding prediction model of a braided-meandering reservoir. This model will promote understanding of the extent of fluvial deposits and sand-body distribution of P1h8, thus elucidating hydrocarbon-bearing sand units of the Ordos Basin for future exploration.

Spatiotemporal patterns of population response in the visual cortex under isoflurane: from wakefulness to loss of consciousness.

Anesthetic drugs are widely used in medicine and research to mediate loss of consciousness (LOC). Isoflurane is a commonly used anesthetic drug; however, its effects on cortical sensory processing, in particular around LOC, are not well understood. Using voltage-sensitive dye imaging, we measured visually evoked neuronal population response from the visual cortex in awake and anesthetized mice at 3 increasing concentrations of isoflurane, thus controlling the level of anesthesia from wakefulness to deep anesthesia. At low concentration of isoflurane, the effects on neuronal measures were minor relative to the awake condition. These effects augmented with increasing isoflurane concentration, while around LOC point, they showed abrupt and nonlinear changes. At the network level, we found that isoflurane decreased the stimulus-evoked intra-areal spatial spread of local neural activation, previously reported to be mediated by horizontal connections, and also reduced intra-areal synchronization of neuronal population. The synchronization between different visual areas decreased with higher isoflurane levels. Isoflurane reduced the population response amplitude and prolonged their latencies while higher visual areas showed increased vulnerability to isoflurane concentration. Our results uncover the changes in neural activity and synchronization at isoflurane concentrations leading to LOC and suggest reverse hierarchical shutdown of cortical areas.

Revisiting horizontal connectivity rules in V1: from like-to-like towards like-to-all.

Horizontal connections in the primary visual cortex of carnivores, ungulates and primates organize on a near-regular lattice. Given the similar length scale for the regularity found in cortical orientation maps, the currently accepted theoretical standpoint is that these maps are underpinned by a like-to-like connectivity rule: horizontal axons connect preferentially to neurons with similar preferred orientation. However, there is reason to doubt the rule's explanatory power, since a growing number of quantitative studies show that the like-to-like connectivity preference and bias mostly observed at short-range scale, are highly variable on a neuron-to-neuron level and depend on the origin of the presynaptic neuron. Despite the wide availability of published data, the accepted model of visual processing has never been revised. Here,we review three lines of independent evidence supporting a much-needed revision of the like-to-like connectivity rule, ranging from anatomy to population functional measures, computational models and to theoretical approaches. We advocate an alternative, distance-dependent connectivity rule that is consistent with new structural and functional evidence: from like-to-like bias at short horizontal distance to like-to-all at long horizontal distance. This generic rule accounts for the observed high heterogeneity in interactions between the orientation and retinotopic domains, that we argue is necessary to process non-trivial stimuli in a task-dependent manner.

Experimental research on the in-plane performance of discontinuous modular diaphragms

Modular steel buildings (MSBs) are assembled from factory-manufactured modules and have been becoming more popular with higher construction efficiency. However, MSBs show quite different in-plane load-transferring behavior from traditional steel frame structures due to the diaphragm discontinuity, and in-depth researches will be needed to acquire better knowledge of its structural behavior. In this paper, the in-plane performance of modular diaphragms was investigated through the half-scaled experiments on the assembled modules, with two types of horizontal connections and double-layer diaphragm structure being taken account. The load–displacement curves, the displacement distribution as well as the strain development were all analyzed and the effects of different horizontal connections as well as double-layer diaphragm on the in-plane performance of diaphragm were discussed. Afterwards, one analytical model will be proposed to evaluate the in-plane transferring ability of modular diaphragms, where two key parameters are defined including displacement inconsistency factor (DIF) and effective lateral stiffness (ELS). The results from experiments and analytical models indicated the modular diaphragms were far from rigid floor assumption and the horizontal connections could make great differences in in-plane load transferring ability of modular diaphragms.

Multiscale computational framework for predicting viscoelasticity of red blood cells in aging and mechanical fatigue

Red blood cells (RBCs) experience significant cyclic deformation through large elastic stretching and relaxation as they circulate in the bloodstream. Such hundreds of thousands times cell deformation causes cumulative fatigue damage to the circulating RBCs, leading to alterations in cell deformability and membrane viscoelasticity. Here, we employ a two-step multiscale computational framework based on coarse-grained molecular dynamics (CGMD) and dissipative particle dynamics (DPD) to probe the viscoelastic properties of the surface-altered RBCs in aging and mechanical fatigue, using experimental information on the molecular structures of both RBC membrane and cytosolic Hb as well as Hb concentration of RBC cytosol. We perform CGMD simulations to compute the shear modulus and membrane viscosity of a small RBC patch with altered horizontal connectivity within spectrin network; meanwhile, we compute the shear viscosity of RBC cytosol under different Hb concentrations. We then use these computed parameters as inputs for a more coarse-grained DPD-based RBC model at the whole-cell level to probe cell deformation, dynamic relaxation, viscoelastic performance of the altered RBC membrane. We find that the RBC membrane rigidity increases with the enhanced horizontal connectivity within spectrin network, but by a factor less than the effective membrane viscosity, resulting in an elevated characteristic relaxation time with increasing fatigue cycles. In addition, we quantify the two-dimensional storage and loss moduli of RBC membrane under time-dependent loading, revealing that the loss modulus is much larger than the storage modulus throughout the entire frequency range covered by the simulations, especially under enhanced connectivity in the cytoskeletal network, which is analogous to the performance of typical viscoelastic materials. These quantitative findings provide unique insights into the progressive damage of circulating RBCs, and demonstrate the capability of the two-step multiscale framework in effectively predicting the altered viscoelastic properties of RBCs influenced by in vivo aging and mechanical fatigue.

Contrast adaptation of flankers reduces collinear facilitation and inhibition

Increase (facilitation) or decrease (inhibition) of contrast sensitivity for a Gabor patch presented between two collinear flankers is a well-studied contextual modulation phenomenon. It has been suggested that this effect has its neural bases in the primary visual cortex, specifically the horizontal connections between hypercolumns with similar orientation and spatial frequency selectivity. Another typical phenomenon dependent on early visual areas is contrast adaptation, in which the neural response to a contrast stimulus is decreased after exposure. Here, we investigated the effect of contrast adaptation of the flankers on the magnitude of collinear modulation by testing whether contrast adaptation reduced collinear facilitation and collinear inhibition. Results showed dissociation in the effect of collinear flanker adaptation, which increased contrast thresholds for the target in the facilitatory configuration and reduced them in the inhibitory configuration. Moreover, the effect was specific for the collinear configuration, since contrast adaptation of orthogonal flankers did not affect the contrast of the target, pointing towards the involvement of early visual units specific for orientation. Surprisingly, the same pattern of results was also confirmed when the inhibitory configuration was tested with low-contrast flankers, indicating that the effect of adaptation does not depend on a decrease in perceived contrast of the flankers. Taken together, these results suggest that contrast adaptation disrupts collinear modulation and that contrast thresholds can be affected by adapting portions of the visual field outside the receptive field of the units processing the contrast of the target (i.e., the flankers).

СТРАТЕГІЇ ОСВІТИ ДЛЯ КРЕАТИВНОГО СУСПІЛЬСТВА

The article is devoted to considering the conditions for building a creative society in Ukraine and the role of education in this. Since the main goal of a creative society is to identify and maximize the use of intellectual resources of people, this reveals a demand for professionalism, a high level of education and the realization of the creative potential of an individual. Such a concept marks the transition from individual creativity to creativity as a social phenomenon. A creative society is characterized by horizontal network connections, self-organization, the formation of a creative class, and the development of creative and cultural industries. All this provokes changes in education, which primarily has a social mission, and its "product" directly affects all spheres of life. So, it is not only about educational programs aimed at the technologies of the future, the spread of creative incubators and support for startups. It is about the formation of humanitarian intellectual capital of the country, its cultural diversity, strengthening of the culture of partnership and trust, creation of creative ecosystems in which higher education institutions are key institutions.

Investigating spatiotemporal dynamics of Lake Poyang wetland for the recent century

鄱阳湖是我国最大淡水湖和长江中游仅存的两个通江湖泊之一，重建其近百年自然通江的湖泊湿地演变过程，对于鄱阳湖湿地生态修复与保护具有重要意义.本研究基于两期历史时期地形图和遥感产品，构建了1930s、1970s、1990s、2000s和2010s鄱阳湖湿地格局变化数据集，探究了土地利用方式改变和水文连通变化对鄱阳湖湿地变化的影响.结果表明：鄱阳湖湿地面积由1930s的5024.3 km²下降至2010s的3232.7 km²，近百年损失率高达35.7%，其中1930s-1970s时期面积变化最为显著，损失率达33.2%，且主要集中分布于赣江与饶河的入湖尾闾地区和南部康山圩.湖泊湿地向耕地的转移是鄱阳湖湿地丧失的主要形式，1930s以来，共有累计1149.6 km²的湖泊湿地受垦殖的作用转变为耕地.闸坝与圩垸导致的水文连通性降低加剧了鄱阳湖自然通江的湖泊湿地格局的变化.相较1930s，累计有683.4 km²的湖泊湿地与主湖相阻隔，水文节律完全独立于通江水域.基于地统计学的水文连通函数曲线也表明，近百年来鄱阳湖的横向和纵向水文连通性均呈现一定程度的下降，且在1990s以后保持相对稳定的状态.本研究能够为鄱阳湖乃至长江中游湖泊湿地生态修复与生态系统服务提升提供参考状态与客观资料.;Lake Poyang is the largest freshwater lake in China and one of the two remaining lakes freely connected with the Yangtze River in the middle reaches of the Yangtze River. Reconstruction of the spatiotemporal dynamics of the lake-wetland that are freely connected with the Yangtze River for the recent century is of great significance for Lake Poyang wetland restoration and protection and ecosystem services promotion. The present study used two periods of historic topographic maps and remote sensing products to reconstruct the Yangtze connected lake-wetland dynamics database covering the 1930s, 1970s, 1990s, 2000s and 2010s. Impacts of land use changes as well as hydrological connectivity changes on lake-wetland dynamics were explored. Results showed that Lake Poyang wetland area decreased from 5024.3 km² in the 1930s to 3232.7 km² in the 2010s, with a loss rate of 35.7%, of which most of the loss occurred between the 1930s and 1970s, with a loss rate of 33.2%. The lake-wetland loss is mainly distributed in the tail of Gan and Rao Rivers and the Kangshan polder. Moreover, a total of 1149.6 km² of lake-wetland has been converted into cultivated land due to reclamation since the 1930s, which is the main land use change type of lake-wetland. In addition, compared with the 1930s, a total of 683.4 km² lake-wetland was separated from the main lake, from which the hydrological rhythm was independent since then. The geostatistical hydrological connectivity curve of different historic periods also indicated that both the horizontal and longitudinal hydrological connectivity decreased for certain extent for the past century and remained relative stable since the 1990s. This study could provide reference states and data basis for the ecological restoration and ecosystem service promotion of Lake Poyang and even for the middle reaches of the Yangtze River.

Shifting Perspectives on the Cold War

Shifting Perspectives on the Cold War Corinna R. Unger Lorenz M. Lüthi, Cold Wars: Asia, The Middle East, Europe. 756 pp. Cambridge: Cambridge University Press, 2020. ISBN-13 978-1108407069. $34.99. Thirty years after the end of the Cold War, historians interested in the conflict face both a challenge and an opportunity. The challenge is to find new angles in a field that has been studied for decades and with high intensity, to critically deal with the epistemological legacies of historical research produced under Cold War conditions, and to define what "Cold War history" means at a time when the field has branched out in a variety of directions.1 The opportunity is to break free from older views anchored in ideological debates of the pre-1989 period and to develop fresh perspectives that benefit from and contribute to developments in other fields, especially global history and his new international history. One of the most influential publications in this regard has been Odd Arne Westad's The Global Cold War, which was decisive in turning the gaze from Europe to parts of the world that, until then, had been considered merely venues in which the superpowers competed with each other. The Cold War term "proxy wars" captured this older view—which, by and large, denied any kind of agency to countries, governments, and people in Asia, Africa, and Latin America.2 Lorenz M. Lüthi's new book presents a continuation of the effort to decenter the history of the Cold War. Lüthi does so by offering an account of regional Cold War conflicts as they played out in Asia, the Middle East, and Europe and by investigating what he calls the "connections and spillover effects within" those three regions (2). The book consists of seven parts. The [End Page 181] first part, on "elusive unities," looks at the relations of the United Kingdom, the United States, and the Soviet Union with the Arab League, the "Free World," and the socialist countries, respectively, from the 1940s to the 1980s. This is followed by a section in which the regional conflicts in Asia and the Middle East are covered in one part each. The parts deal with the place of Europe between the superpowers; European détente; and, finally, with the "end of the regional Cold Wars." Lüthi's aim is to challenge the traditional interpretation of the Cold War as a conflict between the United States of America and the Soviet Union, and as having taken place predominantly on the European continent. He argues that this interpretation is misleading in that it ignores the developments in other parts of the world—trends that cannot just be dismissed as derivatives of the superpower Cold War. Among the most important of these processes are decolonization and the emergence of independent nation-states in Asia and the Middle East, which have often been presented as taking place in parallel to the Cold War rather than preceding and shaping it. By paying close attention to the histories of these regions as such, rather than treating them as satellites whose histories were shaped by Moscow or Washington, Lüthi makes an effective argument about the need to rethink not only the geographical center but also the chronology of the Cold War. As an effect of Lüthi's shift in focus and his attention to "structural change at the regional and national levels, and to horizontal connections among different world regions" (1), the image of a singular, homogenous Cold War is replaced by an interpretation that highlights the pluralistic, heterogeneous nature of the conflict. In this context, the author demonstrates how in many cases existing political and economic conflicts between neighboring countries, ethnic factions, or religious groups contributed to and got caught up in Cold War dynamics but were not the result of the Cold War. This is perhaps the most important achievement of the book: it convincingly challenges the traditional account of the Cold War as a conflict determined and defined by the two superpowers, demonstrating that the Cold War was inextricably tied to events in the Middle East, Asia, and Europe that existed independently of the Cold War but...

PROFESSIONAL TEACHERS` COMMUNITIES: WHERE TO START AND WHERE TO MOVE

The article highlights the ways of teachers` cohesion in the professional communities with the developed horizontal connections. In the process of scientific searching the authors have analyzed the scientific literature on the issues of the study and the legislative documents, which regulate the activities of the professional communities of educators in Ukraine. It was installed that centers of teachers` professional development play an important role in the process of creating and coordination of the activities of professional communities. It is emphasized that professional communities in Ukraine are at the stage of development, and the centers of teachers` professional development often act through the method “sorting the options” and need detailed information regarding possible actions. The factors, with influence on teachers` cohesion in the teachers` communities are identified: the willingness to get the new information; possibility of joint searching of the ways of professional difficulties` overcoming; the need for support from the colleagues and exchange of experience with others. The arguments are provided in favor of teachers` participation in the professional communities, which can be used by the centers of teachers` professional development in the process of informing educators. Characteristics, which influence on the effectiveness of teachers` professional communities are identified: teachers` engagement in the discussions; observations of teachers` lessons of each other; providing and receiving the feedback to improve professional practices; exchange of experience and interactions based on “equal to equal” principle; sharing school`s mission and values; team approach to planning the joint work in the developing students` competencies; discussing the moments, which require additional attention; group responsibility for achieving by students of their educational results.

A Numerical Analysis on Coral Larval Networks across Reef Areas on the Northwest Coast of Okinawa Main Island, Japan

Coral bleaching has recently occurred extensively over the world’s oceans, primarily due to high water temperatures. Mesophotic corals that inhabit at depths of approximately 30–150 m are expected to survive during bleaching events and to reseed shallow water corals afterward. In particular, in Okinawa, Japan, mesophotic coral ecosystems (MCEs) have been reported to serve as a refuge to preserve genotypic diversities of bleaching-sensitive corals. Connectivity of larval populations between different habitats is a key element that determines the area to be conserved for desirable coral ecosystems. Coral larvae generally behave passively to the surrounding currents and are transported by the advective and dispersive effects of ambient ocean currents. Thus, numerical ocean circulation models enable us to quantify connectivity with detailed spatiotemporal network structures. Our aim in this study is to quantify the short-distance and vertical connectivity of coral larvae in reef areas on the northwest coast of Okinawa Main Island. For the reason that both short-distance and vertical larval transport are influenced by complex nearshore topography, a very high-resolution 3-D circulation model is required. Therefore, we developed a quadruple nested high-resolution synoptic ocean model at a lateral spatial resolution of 50 m, coupled with an offline 3-D Lagrangian particle-tracking model. After validation of the developed model, short-distance horizontal coral connectivity across reef areas on the northwest coast was successfully evaluated. Furthermore, a series of Lagrangian particle release experiments were conducted to identify the vertical coral migration and 3-D connectivity required for the preservation of MCEs. The model revealed that coral larvae released from the semi-enclosed areas tended to remain near the source area, whereas they were diffused and dispersed gradually with time. The mesophotic corals were dispersed vertically to the deeper zone below the mixed layer, while upward transport occurred to induce the mesophotic corals to emerge near the surface, under the influence of the surface mixed layer. The model results solidly indicated significant connectivity between MCEs and shallow coral ecosystems.

Columnar processing of border ownership in primate visual cortex.

To understand a visual scene, the brain segregates figures from background by assigning borders to foreground objects. Neurons in primate visual cortex encode which object owns a border (border ownership), but the underlying circuitry is not understood. Here, we used multielectrode probes to record from border ownership-selective units in different layers in macaque visual area V4 to study the laminar organization and timing of border ownership selectivity. We find that border ownership selectivity occurs first in deep layer units, in contrast to spike latency for small stimuli in the classical receptive field. Units on the same penetration typically share the preferred side of border ownership, also across layers, similar to orientation preference. Units are often border ownership-selective for a range of border orientations, where the preferred sides of border ownership are systematically organized in visual space. Together our data reveal a columnar organization of border ownership in V4 where the earliest border ownership signals are not simply inherited from upstream areas, but computed by neurons in deep layers, and may thus be part of signals fed back to upstream cortical areas or the oculomotor system early after stimulus onset. The finding that preferred border ownership is clustered and can cover a wide range of spatially contiguous locations suggests that the asymmetric context integrated by these neurons is provided in a systematically clustered manner, possibly through corticocortical feedback and horizontal connections.

Emergence of Lie Symmetries in Functional Architectures Learned by CNNs.

In this paper we study the spontaneous development of symmetries in the early layers of a Convolutional Neural Network (CNN) during learning on natural images. Our architecture is built in such a way to mimic some properties of the early stages of biological visual systems. In particular, it contains a pre-filtering step ℓ0 defined in analogy with the Lateral Geniculate Nucleus (LGN). Moreover, the first convolutional layer is equipped with lateral connections defined as a propagation driven by a learned connectivity kernel, in analogy with the horizontal connectivity of the primary visual cortex (V1). We first show that the ℓ0 filter evolves during the training to reach a radially symmetric pattern well approximated by a Laplacian of Gaussian (LoG), which is a well-known model of the receptive profiles of LGN cells. In line with previous works on CNNs, the learned convolutional filters in the first layer can be approximated by Gabor functions, in agreement with well-established models for the receptive profiles of V1 simple cells. Here, we focus on the geometric properties of the learned lateral connectivity kernel of this layer, showing the emergence of orientation selectivity w.r.t. the tuning of the learned filters. We also examine the short-range connectivity and association fields induced by this connectivity kernel, and show qualitative and quantitative comparisons with known group-based models of V1 horizontal connections. These geometric properties arise spontaneously during the training of the CNN architecture, analogously to the emergence of symmetries in visual systems thanks to brain plasticity driven by external stimuli.

Representing a dense network of ponds and reservoirs in a semi-distributed dryland catchment model

The mismatch between natural water availability and demand in dryland regions is overcome by reservoirs of different sizes with the purpose of storing water. The increase in population in dryland regions and the consequent growth in water demand expanded the construction of small reservoirs, generating in these regions a dense network of reservoirs, which increases the complexity of modeling these hydrological systems. For dryland watersheds modeling with daily time-step, the horizontal connectivity of the reservoir network needs careful representation in order to achieve acceptable model performance, including cumulative effects of reservoirs. However, the horizontal connectivity of reservoir networks is often less investigated in large-scale catchment models. This work presents an innovative way of implementing the dense-reservoir network into the widely used eco-hydrological model Soil and Water Assessment Tool (SWAT), with detailed representation of large and small reservoirs, and an extensive analysis about the cumulative impact of small reservoirs on the horizontal hydrological connectivity for large-scale dryland catchments. A two-fold cross-validation was used against streamflow at a catchment outlet and against in-catchment reservoir water levels. The model daily performance was acceptable despite the input data uncertainty, with good reliability for peak flow in wet years, for nonflow periods and for the rising limb of the hydrograph. The efforts in the parameterization of reservoirs and aggregation of ponds allowed a better analysis of the hydrological processes and their impacts in the catchment. The results showed that small reservoirs decreased the streamflow, but had a low impact on catchment retention and water losses, with 2% of water retention in wet years. However, the water retention reached 9% in dry years, which may worsen periods of water scarcity in the large reservoirs. The spatial representation of small reservoirs for a high-density network in the SWAT model and the results of the cumulative impact of small reservoirs may be relevant for a better understanding of hydrology in dryland catchments, and can be applied to catchments in similar climatic and socio-economic environments.

Strong horizontal and vertical connectivity in the coral Pocillopora verrucosa from Ludao, Taiwan, a small oceanic island.

Mesophotic habitats could be sheltered from natural and anthropogenic disturbances and act as reproductive refuges, providing propagules to replenish shallower populations. Molecular markers can be used as proxies evaluating the connectivity and inferring population structure and larval dispersal. This study characterizes population structure as well as horizontal and vertical genetic connectivity of the broadcasting coral Pocillopora verrucosa from Ludao, a small oceanic island off the eastern coast of Taiwan. We genotyped 75 P. verrucosa specimens from three sites (Gongguan, Dabaisha, and Guiwan) at three depth ranges (Shallow: 7–15 m, Mid-depth: 23–30 m, and Deep: 38–45 m), spanning shallow to upper mesophotic coral reefs, with eight microsatellite markers. F-statistics showed a moderate differentiation (FST = 0.106, p<0.05) between two adjacent locations (Dabaisha 23–30 and Dabaisha 38–45 m), but no differentiation elsewhere, suggesting high levels of connectivity among sites and depths. STRUCTURE analysis showed no genetic clustering among sites or depths, indicating that all Pocillopora individuals could be drawn from a single panmictic population. Simulations of recent migration assigned 30 individuals (40%) to a different location from where they were collected. Among them, 1/3 were assigned to deeper locations, 1/3 to shallower populations and 1/3 were assigned to the right depth but a different site. These results suggest high levels of vertical and horizontal connectivity, which could enhance the recovery of P. verrucosa following disturbances around Ludao, a feature that agrees with demographic studies portraying this species as an opportunistic scleractinian.