Greater Connectivity Research Articles

Modeling larval dispersal and connectivity for Atlantic sea scallop (Placopecten magellanicus) in the Middle Atlantic Bight

Larval Atlantic sea scallops (Placopecten magellanicus) simulations in the Middle Atlantic Bight (MAB) from 2006 to 2012 were performed to investigate annual and inter-annual dispersal and connectivity patterns among stock regions. These simulations used a circulation model based on the Regional Ocean Modeling System (ROMS) and an individual-based larval model (IBM) that included larval behavior. The circulation model used realistic dynamical forcing (e.g., winds, tides, and open ocean boundary conditions), thermo-dynamical fluxes (e.g., solar radiations, sensible and latent heating), and hydrological forcing; the larval IBM included vertical swimming and sinking behaviour, temperature-dependent growth, and settlement. Simulated larvae that reach settlement size and suitable habitat in 45 days are considered ‘successful’, and two regions are considered ‘connected’ by larval dispersal when larvae successfully disperse from one region to the other. In general, simulated larval dispersal patterns varied seasonally (28% higher in September and October compared to May and June), among years (2007 through 2009 had 5% lower larval success during August and September compared to other years), and spatially, with larvae released from the northern regions like Long Island acting as a substantive larval source with 14% greater dispersal success and 15% greater connectivity with other regions than those released elsewhere. Over the seven years simulated, the MAB scallop stocks showed high rates of connectivity to regions to the south and more limited and variable connectivity to regions to the north. In species like sea scallops with limited adult mobility, larval dispersal supplies recruits, enables range expansion, and connects populations. Thus, appreciation of dispersal patterns are essential for fishery management of this economically valuable stock.

Neural Correlates of Compulsive Alcohol Seeking in Heavy Drinkers

BackgroundCompulsive alcohol use, the tendency to continue alcohol seeking and taking despite negative consequences, is a hallmark of alcohol use disorder. Preclinical rodent studies have suggested a role for the medial prefrontal cortex, anterior insula, and nucleus accumbens in compulsive alcohol seeking. It is presently unknown whether these findings translate to humans. We used a novel functional magnetic resonance imaging paradigm and tested the hypothesis that heavy drinkers would compulsively seek alcohol despite the risk of an aversive consequence, and that this behavior would be associated with the activity of frontostriatal circuitry. MethodsNon–treatment-seeking heavy and light drinkers (n = 21 per group) completed a functional magnetic resonance imaging paradigm in which they could earn alcohol or food points at various threat levels (i.e., various probabilities of incurring an aversive consequence). Brain function was evaluated when individuals had the opportunity to earn reward points at the risk of an aversive consequence, an electric shock on the wrist. ResultsCompared with light drinkers, heavy drinkers attempted to earn more aversion-paired alcohol points. Frontostriatal circuitry, including the medial prefrontal cortex, anterior insula, and striatum, was more active in this group when viewing threat-predictive alcohol cues. Heavy drinkers had increased connectivity between the anterior insula and the nucleus accumbens. Greater connectivity was associated with more attempts to earn aversion-paired alcohol points and self-reported compulsive alcohol use scores. ConclusionsHigher activation of frontostriatal circuitry in heavy drinkers may contribute to compulsive alcohol seeking. Treatments that disrupt this circuitry may result in a decrease in compulsive alcohol use.

Structural Transformation of the Void-Pore Space of a Lime Reservoir During HCl Treatment

Morphological changes of a lime reservoir pore structure that occurred during flooding with HCl solution (10 wt.%) are studied. A new method of measuring the lateral area of a wormhole is proposed for calculating the Damkohler number and consists of segmenting its boundaries into a digital model, calculating the surface area of resulting complicated shape of the flooding channel, and subtracting the area of its ends. The morphological sizes of the pore-channel structures through which the wormhole is subsequently formed differ considerably from the starting pore system by a simpler structure, greater connectivity, less tortuosity of the pore space, and larger pore channels, which are responsible for the initially high permeability. Pores in the starting sample are formed by contact of angular clastic grains. The surface of pore channels is uneven with many outcropping grains. The channels themselves are highly tortuous. After acid flooding, the channel surface evens out and the pore space becomes a dendritic structure of interconnecting tubes

Intellectual Contract

Technological change is altering the nature of contract toward a greater focus on intangible assets. The direction of technological change toward greater connectivity, interoperability, mobile communications, the Internet of Things (IoT), artificial intelligence (AI), virtual inventions, and cooperative research and development (R&D) has profound implications. This article develops a new framework that I refer to as “Intellectual Law” to address this shift. The article introduces the concept of “Intellectual Contract” (IC) to characterize agreements for invention, innovation, and technology adoption. The article also introduces the concept of “Intellectual Tort” (IT) to describe liability including but not limited to misappropriation of trade secrets and infringement of patents, trademarks, and copyrights. Intellectual Law provides a consistent framework for IC, IT and Intellectual Property (IP). The article observes that legal protections for inventors cannot rely solely on what has proven to be a flawed combination of IT and IP. The article argues that greater emphasis on IC would improve both IT and IP. Because IC protects expectation interests it is essential for creating, developing, sharing, and applying intangible assets. IC generates gains from trade that enhance the benefits of inventors, innovators and adopters beyond what can be achieved by IT and IP alone.

Network Structure and Consolidation in the U.S. Airline Industry, 1990–2015

We study the effect of consolidation on airline network connectivity using three measures of centrality from graph theory: Degree; Closeness; and Betweenness. Changes in these measures from 1990 to 2015 imply: (i) the average airport services a greater proportion of possible routes; (ii) the average origin airport is fewer stops away from any given destination; and (iii) the average hub is less often along the shortest route between two other airports. Yet, we find the trend toward greater connectivity in the national network structure is largely unaffected by consolidation—in the form of mergers and codeshare agreements—during this period.

Brain intrinsic network connectivity in individuals with frequent tanning behavior

ABSTRACTBackground: Emergent studies suggest a bidirectional relationship between brain functioning and the skin. This neurocutaneous connection may be responsible for the reward response to tanning and, thus, may contribute to excessive tanning behavior. To date, however, this association has not yet been examined. Objectives: To explore whether intrinsic brain functional connectivity within the default mode network (DMN) is related to indoor tanning behavior. Methods: Resting state functional connectivity (rsFC) was obtained in twenty adults (16 females) with a history of indoor tanning. Using a seed-based [(posterior cingulate cortex (PCC)] approach, the relationship between tanning severity and FC strength was assessed. Tanning severity was measured with symptom count from the Structured Clinical Interview for Tanning Abuse and Dependence (SITAD) and tanning intensity (lifetime indoor tanning episodes/years tanning). Results: rsFC strength between the PCC and other DMN regions (left globus pallidus, left medial frontal gyrus, left superior frontal gyrus) is positively correlated with tanning symptom count. rsFC strength between the PCC and salience network regions (right anterior cingulate cortex, left inferior parietal lobe, left inferior temporal gyrus) is correlated with tanning intensity. Conclusion: Greater connectivity between tanning severity and DMN and salience network connectivity suggests that heightened self-awareness of salient stimuli may be a mechanism that underlies frequent tanning behavior. These findings add to the growing evidence of brain-skin connection and reflect dysregulation in the reward processing networks in those with frequent tanning.

The science of connected ecosystems: What is the role of catchment‐scale connectivity for healthy river ecology?

AbstractRiverine biological communities are highly resilient to extreme flood and/or drying disturbance regimes that would otherwise be destructive because these organisms can recolonise from upstream, floodplain, or hyporheic refugia when suitable conditions return. Healthy rivers require a high degree of connectivity to support complex life cycles of many lotic organisms and associated ecosystem functioning. Similarly, connectivity is required for appropriate geophysical functioning; permitting flux of water and sediment that drives channel‐forming and ecological processes. Ecological and geophysical processes have operated in this temporal and spatial patchwork of disturbance and recovery pre‐Anthropocene. Human impacts are increasing constraints on river and floodplain connectivity, severing many natural pathways, and degrading river ecosystem functioning. River restoration seeks to re‐establish some of those biological and physical connections to enhance some level of system health. However, increasing sediment connectivity may be detrimental to river health in some instances. Strongly connected catchments can transmit excessive quantities of sediment from inappropriate land management, detrimental invasive species can spread more widely, and many ecosystem processes can exceed positive feedback control. Simply restoring connectivity will not necessarily lead to healthy river ecosystems. River management requires a greater understanding of how and when connectivity can and should be restored. Although current thinking is often that greater connectivity is better, we illustrate with examples from New Zealand rivers that this is not always the case. The benefits and costs of maintaining or restoring river connectivity need to be given as much attention as the restoration and maintenance of river systems per se.

Evidence That Default Network Connectivity During Rest Consolidates Social Information.

Brain regions engaged during social inference, medial prefrontal cortex (MPFC) and tempoparietal junction (TPJ), are also known to spontaneously engage during rest. While this overlap is well known, the social cognitive function of engaging these regions during rest remains unclear. Building on past research suggesting that new information is committed to memory during rest, we explored whether one function of MPFC and TPJ engagement during rest may be to consolidate new social information. MPFC and TPJ regions significantly increased connectivity during rest after encoding new social information (relative to baseline and post nonsocial encoding rest periods). Moreover, greater connectivity between rTPJ and MPFC, as well as other portions of the default network (vMPFC, anterior temporal lobe, and middle temporal gyrus) during post social encoding rest corresponded with superior social recognition and social associative memory. The tendency to engage MPFC and TPJ during rest may tune people towards social learning.

Novel Biomarkers of Physical Activity Maintenance in Midlife Women: Preliminary Investigation.

The precision health initiative is leading the discovery of novel biomarkers as important indicators of biological processes or responses to behavior, such as physical activity. Neural biomarkers identified by magnetic resonance imaging (MRI) hold promise to inform future research, and ultimately, for transfer to the clinical setting to optimize health outcomes. This study investigated resting-state and functional brain biomarkers between midlife women who were maintaining physical activity in accordance with the current national guidelines and previously acquired age-matched sedentary controls. Approval was obtained from the Human Subjects Committee. Participants included nondiabetic, healthy weight to overweight (body mass index 19–29.9 kg/m2) women (n = 12) aged 40–64 years. Control group data were used from participants enrolled in our previous functional MRI study and baseline resting-state MRI data from a subset of sedentary (<500 kcal of physical activity per week) midlife women who were enrolled in a 9-month exercise intervention conducted in our imaging center. Differential activation of the inferior frontal gyrus (IFG) and greater connectivity with the dorsolateral prefrontal cortex (dlPFC) was identified between physically active women and sedentary controls. After correcting for multiple comparisons, these differences in biomarkers of physical activity maintenance did not reach statistical significance. Preliminary evidence in this small sample suggests that neural biomarkers of physical activity maintenance involve activations in the brain region associated with areas involved in implementing goal-directed behavior. Specifically, activation of the IFG and connectivity with the dlPFC is identified as a neural biomarker to explain and predict long-term physical activity maintenance for healthy aging. Future studies should evaluate these biomarker links with relevant clinical correlations.

Deepwater slope valley reservoir architecture and connectivity, Brazil

A detailed interpretation was undertaken to improve the description of connectivity and reservoir distribution for a field in the Campos Basin, Brazil. The Miocene reservoir was deposited in a deepwater, channelized turbidite fairway in a slope valley setting. Static pressure data acquired after production start-up indicated communication across the reservoir, but the values varied significantly, implying that the efficiency of communication varies. High-quality 3D seismic in combination with production and well data led to a hierarchical interpretation, from channel element to complex-set scale, which defined key stratigraphic and pressure surfaces. Integration of a high-repeatability 4D monitor survey showed that the 4D response changed at stratigraphic boundaries. The 4D data tied to production indicate that an aquifer is traveling along the base of the reservoir in discrete channels. The use of 4D depth shift data increased confidence in the waterfront interpretation in areas without production data. Aggradational channel complexes in the upper part of the reservoir show baffling at the margins of channel complexes down to the channel element scale. The channel elements are also likely baffled on the margins with greater connectivity downward into the lower, amalgamated unit. The lower unit shows greater lateral continuity in 4D signal, consistent with pressure data that indicate larger depletion over greater distances than the overlying aggradational complexes where producer wells are located. In summary, mapping of reservoir architecture and identification of key stratigraphic surfaces from 3D have reduced uncertainty in reservoir distribution and connectivity. Integration of 4D seismic and production data has provided confirmation of connectivity through the identification of waterfronts and unswept areas of the reservoir.

Neural Markers of Resilience in Adolescent Females at Familial Risk for Major Depressive Disorder

Adolescence is a neurodevelopmental period during which experience-dependent plasticity in brain circuitry may confer vulnerability to depression as well as resilience to disorder. Little is known, however, about the neural mechanisms that underlie resilience during this critical period of brain development. To examine neural functional connectivity correlates of resilience in adolescent females at high and low familial risk for depression who did and did not develop the disorder. A longitudinal study was conducted at Stanford University from October 1, 2003, to January 31, 2017. Sixty-five female adolescents participated in the study: 20 at high risk in whom depression did not develop (resilient), 20 at high risk in whom depression developed (converted), and 25 at low risk with no history of psychopathology (control). We compared functional connectivity between resilient and converted, and between resilient and control, adolescent females using voxelwise 2-sided t tests to examine neural markers of resilience to depression as the main outcomes of interest. Specifically, we assessed differences in connectivity of the limbic (amygdala seed), salience (anterior insula seed), and executive control (dorsolateral prefrontal cortex seed) networks, implicated in emotion regulation. We also examined the association between functional connectivity and life events. Of the 65 participants (mean [SD] age, 18.9 [2.5] years), adolescent females in the resilient group had greater connectivity between the amygdala and orbitofrontal cortex (z score = 0.23; P < .001) and between the dorsolateral prefrontal cortex and frontotemporal regions (z score = 0.24; P < .001) than did converted adolescent females. In adolescent females in the resilient group only, strength of amygdala-orbitofrontal cortex connectivity was correlated with positive life events (r18 = 0.48; P = .03). Resilient adolescent females had greater connectivity within frontal (z score = 0.07; P < .001) and limbic (z score = 0.21; P < .001) networks than did control individuals. Both high-risk groups had greater salience network connectivity: the converted group had greater intranetwork connectivity than did the resilient (z score = 0.13; P < .001) and control (z score = 0.10; P < .001) groups, and the adolescent females in the resilient group had greater salience network connectivity with the superior frontal gyrus than did the converted (z score = 0.24; P < .001) adolescent females. Resilient adolescent females have compensatory functional connectivity patterns in emotion regulatory networks that correlate with positive life events, suggesting that experience-dependent plasticity within these networks may confer resilience to depression. Further studies are warranted concerning connectivity-associated targets for promoting resilience in high-risk individuals.

Increased sensorimotor network connectivity associated with clozapine eligibility in people with schizophrenia

Schizophrenia is a heterogeneous disorder that exhibits variable responsiveness to treatment between individuals. Here we conducted a resting-state functional magnetic resonance imaging (rs-fMRI) study to determine whether resistance to first-line antipsychotics is reflected in resting-state connectivity. rs-fMRI data were collected from 15 people who had failed to respond to first-line antipsychotics (clozapine-eligible) and 10 first-line treatment responders (FLR). Image pre-processing and analysis were performed using FMRIB's software library (FSL). Data was decomposed into spatial and temporal components using independent components analysis. Connectivity within each independent component was compared between groups using t-tests and the Bonferroni correction for multiple comparisons. Gender was added as a covariate. Clozapine-eligible individuals exhibited enhanced functional connectivity within the sensorimotor network compared with FLR. Those eligible for clozapine showed additional connectivity with the precuneus compared with FLR. No other comparisons reached statistical significance and no effect of gender was observed. These data reveal differences in functional connectivity between FLR and those eligible for clozapine and suggest that greater connectivity between the SMN and precuneus may be indicative of treatment resistance in people with schizophrenia.

Restructuring of littoral fish assemblages after drought differs in two lakes at the terminus of a heavily regulated river

AbstractDrought significantly shifts the mix of functional groups present in river ecosystems and abundances of many aquatic fauna decline. The consequences of drought for fish often include the decline of ecological specialists and the predominance of generalist species. However, factors influencing the restructuring of littoral fish assemblages following prolonged drought in heavily regulated rivers are poorly understood. We compared the restructuring of littoral fish assemblages in 2 large connected lakes, which differ in hydrology and habitat availability, after 15 years of drought in their catchment. The once‐abundant and diverse fish assemblages showed limited signs of postdrought recovery after 5 years. There were differences between the 2 lakes related to the species present, their abundances, and the functional groups within fish assemblages. The functional groups present also shifted through time from alien‐dominated to freshwater generalist‐dominated. Only 2 of 5 native fish functional groups (freshwater generalist and diadromous) had increasing abundances (used as a proxy for recovery) following the drought, and these increases only occurred in the lake with the greater connectivity and diversity in habitat and hydrology. In contrast to patterns observed for natives, abundances of alien fishes in the littoral zone of the lakes declined after an initial spike in numbers associated with substantial river flows immediately following drought. This study shows that the recovery of native fish populations following prolonged drought in a heavily regulated semiarid river occurs over a time scale of years and recovery of some extant ecological specialists was incomplete after as many as 5 years.

Functional Neural Correlates of Slower Gait Among Older Adults With Mild Cognitive Impairment.

Subtle, but observable, changes in mobility often exist among older adults with mild cognitive impairment (MCI). Notably, these changes are not inconsequential. Therefore, there is a strong interest to better understand the underlying neural correlates of gait slowing among older adults with MCI. In this study, we aimed to characterize patterns of functional connectivity associated with slower gait speed in older adults with MCI. Forty-nine participants aged 60 years and older with MCI were included in the cross-sectional study. All participants underwent assessments of gait speed and resting state functional magnetic resonance imaging. In this sample of older adults with MCI, slower usual gait was characterized by altered connectivity between the sensorimotor network (SMN) and the frontoparietal network (FPN) (p < .05)-specifically, slower usual gait was associated with greater connectivity between the supplementary motor area (SMA) and the bilateral ventral visual cortices (p = .01); lower connectivity between the SMA and the bilateral superior lateral occipital cortex (p < .01); and lower connectivity between the SMA and the bilateral frontal eye field (p < .01). Altered inter-network functional connectivity between the SMN and FPN may be a neural mechanism for slowing of gait in older adults with MCI.

Granger Causality and Jensen–Shannon Divergence to Determine Dominant Atrial Area in Atrial Fibrillation

Atrial fibrillation (AF) is already the most commonly occurring arrhythmia. Catheter pulmonary vein ablation has emerged as a treatment that is able to make the arrhythmia disappear; nevertheless, recurrence to arrhythmia is very frequent. In this study, it is proposed to perform an analysis of the electrical signals recorded from bipolar catheters at three locations, pulmonary veins and the right and left atria, before to and during the ablation procedure. Principal Component Analysis (PCA) was applied to reduce data dimension and Granger causality and divergence techniques were applied to analyse connectivity along the atria, in three main regions: pulmonary veins, left atrium (LA) and right atrium (RA). The results showed that, before the procedure, patients with recurrence in the arrhythmia had greater connectivity between atrial areas. Moreover, during the ablation procedure, in patients with recurrence in the arrhythmial both atria were more connected than in patients that maintained sinus rhythms. These results can be helpful for procedures designing to end AF.

A hydropedological approach to a mountainous Clayey Humic Dystrudept in the Mantiqueira Range, southeastern Brazil

The Mantiqueira Range region is one of the most important headwaters in southeastern Brazil. In this context, the relationship between pedology and hydrology has been debated and analyzed in recent years, contributing to the creation of a multidisciplinary science call hydropedology. Therefore, the aim of this study was to evaluate the hydropedological properties of a mountainous Clayey Humic Dystrudept in the Mantiqueira Range region, in the state of Minas Gerais, Brazil, comparing two land-uses, native forest and pasture. The hydraulic conductivity results demonstrated that native forest (MFO) has a strong influence on this parameter, offering conditions for movement of water in the soil that are more adequate in this profile than in pasture. These results were supported by pore size distribution analyses which showed that soil from native forest has a greater amount of macropores than soil from pasture as well as greater connectivity between the macropores. In general, the MFO site had greater S index values than the micro-catchment taken from pasture, offering favorable physical conditions for the formation of preferential flowpaths in the soil profile and, therefore, better conditions for groundwater recharge. Soil erosion and water quality results confirmed the importance of native forest areas in the interaction between interception of the direct impact of intense precipitation on the soil surface, and hydropedological attributes, such as saturated hydraulic conductivity and porosity.

Gauging resource exploitation by juvenile Chinook salmon (Oncorhynchus tshawytscha) in restoring estuarine habitat

In the context of delta restoration and its impact on salmonid rearing, success is best evaluated based on whether out‐migrating juvenile salmon can access and benefit from suitable estuarine habitat. Here, we integrated 3 years of post‐restoration monitoring data including habitat availability, invertebrate prey biomass, and juvenile Chinook salmon (Oncorhynchus tshawytscha) physiological condition to determine whether individuals profited from the addition of 364 ha of delta habitat in South Puget Sound, Washington, United States. Productivity in the restored mudflat was comparable to reference sites 3 years after dike removal, surpassing a mean total of 6 million kJ energy from invertebrate prey. This resulted from the development of a complex network of tidal channels and a resurgence in dipteran biomass that was unique to the restoration area. Consequently, a notable shift in invertebrate consumption occurred between 2010 and 2011, whereby individuals switched from eating primarily amphipods to dipteran flies; however, dietary similarity to the surrounding habitat did not change from year to year, suggesting that this shift was a result of a change in the surrounding prey communities. Growth rates did not differ between restored and reference sites, but catch weight was positively correlated with prey biomass, where greater prey productivity appeared to offset potential density‐dependent effects. These results demonstrate how the realized function of restoring estuarine habitat is functionally dependent. High prey productivity in areas with greater connectivity may support healthy juvenile salmon that are more likely to reach the critical size class for offshore survival.

Higher order thalamic nuclei resting network connectivity in early schizophrenia and major depressive disorder

The pulvinar and the mediodorsal (MDN) nuclei of the thalamus are higher order nuclei which have been implicated in directed effort and corollary discharge systems. We used seed-based resting fMRI to examine functional connectivity to bilateral pulvinar and MDN in 24 schizophrenic patients (SZ), 24 major depressive disorder patients (MDD), and 24 age-matched healthy controls. SZ had less connectivity than controls between the left pulvinar and precuneus, left ventral-lateral prefrontal cortex (vlPFC), and superior and medial-frontal regions, between the right pulvinar and right frontal pole, and greater connectivity between the right MDN and left dorsolateral prefrontal cortex (dlPFC). SZ had less connectivity than MDD between the left pulvinar and ventral anterior cingulate (vACC), left vlPFC, anterior insula, posterior cingulate cortex (PCC), and right hippocampus, between the right pulvinar and right PCC, and between the right MDN and right dorsal anterior cingulate (dACC). This is the first study to measure the functional connectivity to the higher order nuclei of the thalamus in both SZ and MDD. We observed less connectivity in SZ than MDD between pulvinar and emotional encoding regions, a directed effort region, and a region involved in representation and salience, and between MDN and a directed effort region.

Species traits and connectivity constrain stochastic community re-assembly

All communities may re-assemble after disturbance. Predictions for re-assembly outcomes are, however, rare. Here we model how fish communities in an extremely variable Australian desert river re-assemble following episodic floods and drying. We apply information entropy to quantify variability in re-assembly and the dichotomy between stochastic and deterministic community states. Species traits were the prime driver of community state: poor oxygen tolerance, low dispersal ability, and high fecundity constrain variation in re-assembly, shifting assemblages towards more stochastic states. In contrast, greater connectivity, while less influential than the measured traits, results in more deterministic states. Ecology has long recognised both the stochastic nature of some re-assembly trajectories and the role of evolutionary and bio-geographic processes. Our models explicitly test the addition of species traits and landscape linkages to improve predictions of community re-assembly, and will be useful in a range of different ecosystems.

Keep on carryin' on: Recent research on the LGBTQ history of the American South

AbstractTwenty years have elapsed since the publication of Carryin' On in the Lesbian and Gay South, edited by historian John Howard. The essays in that collection challenged the bicoastal and metro‐normative bias of American gay and lesbian history. Since then, scholars, activists, and local community members have continued to refine our understanding of the regionally specific ways—the four R's of race, religion, rurality, and resilience—through which sex and sexuality are understood and embodied in the American South. Oral history, constantly improving technology, and greater connectivity through the Internet are facilitating conversations across disciplines and beyond the University. Whereas early Southern gay and lesbian scholarship suffered from a long tradition of queer exclusion from the archive and a devaluing of queer lives, the variety of hybrid community and university LGBTIQ+ documentation projects across the south evidence a sea change. Far from perfect, the field of Southern lesbian, gay, bisexual, transgendered, and queer history is becoming ever more diverse and inclusive.