Strong Local Connectivity Research Articles

An ergodic and isotropic zero-conductance model with arbitrarily strong local connectivity

An ergodic and isotropic zero-conductance model with arbitrarily strong local connectivity

Between solid and liquid experience in a socialist port: Gdańsk shipyard workers at the turn of the 1980s

This article analyzes the Gdańsk shipyard workers, a core group that launched the August 1980 strike. It approaches the phenomenon against the backdrop of the socialist port, regardless of the complexities of the political process. Changing globalizing markets, domestic Polish policies towards socialist ports, and the reactions of shipyard workers to local and global changes all played a central role in defining the experience of work at Gdańsk Shipyard. Its workers were under pressure not only from local conditions, but also, like their foreign counterparts, faced a severe and prolonged crisis in global shipbuilding, evident in reduced demand for new vessels, rapidly evolving regulations and technology, layoffs and fierce competition. As industrial workers, they had strong local connections. As port workers, they were sea-oriented and characterized by occupational mobility. This dual nature – between solidity and liquidity – helped foster cross-sectional unity within Poland and internationally, but also caused dissatisfaction. The article continues by explaining how shipyard workers adapted in the face of new challenges.

Influence of differential structural deformation on shale reservoirs: a case study of the lower Silurian Longmaxi Shale in north Guizhou, Southern China

AbstractSouthern China is affected by multi-stage tectonic activities, with strong fold deformation, complex fault systems and poor shale gas preservation conditions. Here, we used shale samples from the lower Silurian Longmaxi shale in the complex tectonic area of Southern China, to study the relationship between differential structural deformation, and pore structure and adsorption capacity. According to the deformation mechanism of the shale, it is further divided into brittle-slip rheological deformation (BD) and ductile-slip rheological deformation (DD). The results show that all micro-fractures can be observed under scanning electron microscopy in deformed shale samples, but in shale samples with different types of rheological deformation, the micro-fractures have large differences in scale, fracture length and lateral connectivity. The micro-fractures developed in DD shales are small in scale and short in fracture length, but have strong local connectivity. In contrast, brittle minerals are more developed in BD shales, and interlayer shearing has formed micro-fractures with large fracture length and good lateral connectivity, which is beneficial for later fracturing. In these two types of deformed shales, pores in organic matter are rare, and sporadic organic pores have small pore size and poor connectivity. The total pore volume (1.8–2.4 × 10−2 cm3 g–1) of BD shale samples is higher than that of DD shale samples (0.8–1.6 × 10−2 cm3 g–1). There is a positive correlation between total pore volume and quartz content. In addition, the specific surface area (12–18 m2 g–1) of DD shale samples is larger than that of BD shale samples (6–12 m2 g–1).

Functional connectivity changes detected with magnetoencephalography after mild traumatic brain injury.

Mild traumatic brain injury (mTBI) may affect normal cognition and behavior by disrupting the functional connectivity networks that mediate efficient communication among brain regions. In this study, we analyzed brain connectivity profiles from resting state Magnetoencephalographic (MEG) recordings obtained from 31 mTBI patients and 55 normal controls. We used phase-locking value estimates to compute functional connectivity graphs to quantify frequency-specific couplings between sensors at various frequency bands. Overall, normal controls showed a dense network of strong local connections and a limited number of long-range connections that accounted for approximately 20% of all connections, whereas mTBI patients showed networks characterized by weak local connections and strong long-range connections that accounted for more than 60% of all connections. Comparison of the two distinct general patterns at different frequencies using a tensor representation for the connectivity graphs and tensor subspace analysis for optimal feature extraction showed that mTBI patients could be separated from normal controls with 100% classification accuracy in the alpha band. These encouraging findings support the hypothesis that MEG-based functional connectivity patterns may be used as biomarkers that can provide more accurate diagnoses, help guide treatment, and monitor effectiveness of intervention in mTBI.

Dynamics of random neural networks with bistable units.

We construct and analyze a rate-based neural network model in which self-interacting units represent clusters of neurons with strong local connectivity and random interunit connections reflect long-range interactions. When sufficiently strong, the self-interactions make the individual units bistable. Simulation results, mean-field calculations, and stability analysis reveal the different dynamic regimes of this network and identify the locations in parameter space of its phase transitions. We identify an interesting dynamical regime exhibiting transient but long-lived chaotic activity that combines features of chaotic and multiple fixed-point attractors.

The development of regional functional connectivity in preterm infants into early childhood

Resting state networks are proposed to reflect the neuronal connectivity that underlies cognitive processes. Consequently, abnormal behaviour of these networks due to disease or altered development may predict poor cognitive outcome. To understand how very preterm birth may affect the development of resting state connectivity, we followed a cohort of very preterm-born infants from birth through to 4years of age using resting state functional MRI. From a larger longitudinal cohort of infants born very preterm (<32weeks gestational age), 36 at birth, 30 at term, 21 two-year and 22 four-year resting state fMRI datasets were acquired. Using seed-based connectivity analyses with seeds in the anterior cingulate cortex, posterior cingulate cortex, left and right motor-hand regions and left and right temporal lobes, we investigated local and inter-region connectivity as a function of group and age. We found strong local connectivity during the preterm period, which matured into inter-hemispheric and preliminary default-mode network correlations by 4years of age. This development is comparable to the resting state networks found in term-born infants of equivalent age. The results of this study suggest that differences in developmental trajectory between preterm-born and term-born infants are small and, if present, would require a large sample from both populations to be detected.

Nutrition Education at Farmers Market to Increase Produce Consumption of Consumers and Clients of Food Assistance Programs

Objective: Provide nutrition education at a local farmer’s market to aid in marketing healthy foods available and to create a relationship with farmers’ and food assistance programs to increase produce food donations. Target audience: Farmer’s Market farmers and consumers and local food assistance programs. Theory, Prior Research, Rationale: Nutrition education is not typically part of local food assistance programs. Nutrition assessment demonstrated a lack of use and procurement of fresh foods. Furthermore, local farmers were not connected to food assistance programs and consumers visiting local farmer’s markets were not familiar withmany products sold. By educating consumers on foods available at farmers markets and educating farmer’s on donating food, a greater percentage of local crops will be purchased and/or donated. Description: A nutrition education booth was created for a local farmer’s market. Volunteers of the booth prepared healthy recipes on site using foods sold by farmers. Secondarily, volunteers educated farmers on donating unsold product to local food assistance programs. Procured food was used in food assistance programs. Evaluation: Measurement of pounds of food procured and distributed to food assistance programs and assessment of the use of food procured by clients and food assistance programs. Conclusions and Implications: This program has been successful in procuring fresh fruits and vegetables that would have been wasted and has developed strong local connections between the university and local farmers and food assistance programs. Programming like this has positive outcomes for a number of different partners including less wasted crops and nutrition education. Funding: None.

Effects of colonization asymmetries on metapopulation persistence

Ocean currents, prevailing winds, and the hierarchical structures of river networks are known to create asymmetries in re-colonization between habitat patches. The impacts of such asymmetries on metapopulation persistence are seldom considered, especially rarely in theoretical studies. Considering three classical models (the island, the stepping stone and the distance-dependent model), we explore how metapopulation persistence is affected by (i) asymmetry in dispersal strength, in which the colonization rate between two patches differs in direction, and (ii) asymmetry in connectivity, in which the overall colonization pattern displays asymmetry (circulating or dendritic networks). Viability can be drastically reduced when directional bias in dispersal strength is higher than 25%. Re-colonization patterns that allow for strong local connectivity provide the highest persistence compared to systems that allow circulation. Finally, asymmetry has relatively weak effects when metapopulations maintain strong general connectivity.

The contribution of organic farming to rural development: An exploration of the socio-economic linkages of organic and non-organic farms in England

Organic farming has experienced considerable growth in recent years. Proponents of organic farming point to the environmental and nutritional benefits of organic systems, although these are contested by some. More recently, it has been argued that organic farming can provide rural development benefits through enhanced employment and through closer connections with the local economy, reconnecting consumers with producers and stimulating positive economic multipliers. Against the background of claims made for the rural development potential of organic farming, this paper considers the generation and retention of income, purchasing patterns, and direct employment impacts of a large sample of organic and non-organic farmers in England. The paper reveals some important distinctions between the characteristics of organic and non-organic farms and farmers. It is argued that most of these differences do not stem directly from differences in farming systems but, rather, reflect considerable differences in the people who operate organic farms as well as the distinctive business configurations they frequently adopt. In confirmation of previous findings, organic farms are shown to employ more people, but the data reveal few differences between the local economic connections of organic and non-organic farms. In turn, this suggests that simply comparing organic and non-organic farm businesses is too blunt an approach. Instead, it is important to consider other factors such as the type of enterprises found on the farm and the marketing routes adopted by the business. It is argued that commentators need to adopt a more nuanced approach, recognising differences between farming systems, farm types, the configuration of farm businesses towards different marketing strategies and the inclinations of those who operate such businesses. This shifts the focus of the debate away from simplistic notions that equate organic production with local supply and assume a local economic benefit, towards a broader conception of the local agro-food economy in which some farms have strong local connections while others focus their efforts elsewhere and earn important export income for the local economy.

Academic libraries and regional library systems: how do they stand today?

Given the presence of other networks and recent advances in communication, academic libraries need to examine their membership in regional library systems. In a survey of academic libraries and regional systems in Ohio, continuing education and strong local connections were found to be the main reasons for maintaining membership.

A measure for brain complexity: relating functional segregation and integration in the nervous system.

In brains of higher vertebrates, the functional segregation of local areas that differ in their anatomy and physiology contrasts sharply with their global integration during perception and behavior. In this paper, we introduce a measure, called neural complexity (CN), that captures the interplay between these two fundamental aspects of brain organization. We express functional segregation within a neural system in terms of the relative statistical independence of small subsets of the system and functional integration in terms of significant deviations from independence of large subsets. CN is then obtained from estimates of the average deviation from statistical independence for subsets of increasing size. CN is shown to be high when functional segregation coexists with integration and to be low when the components of a system are either completely independent (segregated) or completely dependent (integrated). We apply this complexity measure in computer simulations of cortical areas to examine how some basic principles of neuroanatomical organization constrain brain dynamics. We show that the connectivity patterns of the cerebral cortex, such as a high density of connections, strong local connectivity organizing cells into neuronal groups, patchiness in the connectivity among neuronal groups, and prevalent reciprocal connections, are associated with high values of CN. The approach outlined here may prove useful in analyzing complexity in other biological domains such as gene regulation and embryogenesis.

A current source density analysis of field potentials evoked in slices of visual cortex.

The method of one-dimensional current source density (CSD) analysis was applied to field potentials recorded from 350 microns thick slices of the primary visual cortex of rats and cats. Field potentials were elicited by stimulation of the white matter and recorded along trajectories perpendicular to the cortical layers at spatial intervals of 25 to 50 microns. The resulting CSD distributions resembled closely those recorded from the cat visual cortex "in vivo". The responses with the shortest latency were distinct sinks in layers IV and VI probably reflecting monosynaptic EPSP's from specific thalamic afferents. From layer IV activity was relayed along three major routes: 1. to the supragranular layers via strong local connections to layer III and from there via both short and long range connections to layer II, 2. to targets within layer IV, and 3. to layer V. The source distributions suggest that the projections to layers III and II terminate on the proximal and distal segments, respectively, of apical dendrites of layer III pyramidal cells while the projection to layer V contacts the apical dendrites of layer VI pyramidal cells. These results indicate that all the excitatory pathways that are detectable with the CSD technique in the "in vivo" preparation remain intact in 350 micron thick cortical slices. However, in the slice paired pulse stimulation did not lead to a depression of the response to the second stimulus while this is the case "in vivo". This might be due to reduced inhibition in the slice which has been reported by several authors.

Local connectivity of spaces of finite group actions on 3-manifolds

We show that the space A PL ( G, M) of PL-actions of a finite group G on a closed 3-manifold M with compact-open topology is strongly locally connected. The same proof can be used to show the strong local connectivity of the space A DIFF( G, M) of C ∞-actions with C 0-topology.

The Sale of Fiscal Offices and the Decline of Royal Authority in the Viceroyalty of Peru, 1633—1700

T he decision of the Spanish crown in 1633 to begin the systematic sale of high-ranking treasury appointments in the Indies had far-reaching consequences for the administration of royal finance in the Viceroyalty of Peru. The viceregal treasury, centered in Lima, exercised broad powers over financial matters in the realm; and the implementation of all crown revenue policies depended on the loyalty and efficiency of its officers. Throughout the seventeenth century, treasury officials (Oficiales reales) acted as political brokers: mediating between the financial demands of the crown and the frequent resistance of taxpayers in the viceroyalty to new government levies, and helping to maintain the political balance of power essential to the cohesion of the empire.1 The sale of these important fiscal appointments after 1633 eventually tipped this balance pronouncedly in favor of local citizens as purchasers with strong local connections came to dominate the treasury. The political changes brought about by the sales between 1633 and 1700 proved particularly damaging to royal authority in the Viceroyalty of Peru. The seventeenth century was a time of financial crisis for the Hapsburg monarchy, when officials in Madrid needed increased contributions from the viceregal treasury to help stem the economic and military decline of Spain in Europe.2 Selling treasury offices yielded useful