Hub-spoke Networks Research Articles

Systemic vasculitis involving the kidney: the nephropathologist's point of view.

Kidneys are often targets of systemic vasculitis (SVs), being affected in many different forms and representing a possible sentinel of an underlying multi-organ condition. Renal biopsy still remains the gold standard for the identification, characterization and classification of these diseases, solving complex differential diagnosis thanks to the combined application of light microscopy (LM), immunofluorescence (IF) and electron microscopy (EM). Due to the progressively increasing complexity of renal vasculitis classification systems (e.g. pauci-immune vs immune complex related forms), a clinico-pathological approach is mandatory and adequate technical and interpretative expertise in nephropathology is required to ensure the best standard of care for our patients. In this complex background, the present review aims at summarising the current knowledge and challenges in the world of renal vasculitis, unveiling the potential role of the introduction of digital pathology in this setting, from the creation of hub-spoke networks to the future application of artificial intelligence (AI) tools to aid in the diagnostic and scoring/classification process.

Improvements in digital pathology equipment for renal biopsies: updating the standard model.

Digital pathology can improve the technical and interpretative workflows in nephropathology by creating hub-spoke networks and virtuous collaboration projects among centers in different geographical regions. New high-resolution fast-scanning instruments combined with currently existing equipment were tested in a nephropathology hub to evaluate possible upgrading in the routine processing phases. The scanning performance of two different instruments (Aperio vs hybrid MIDI II) was evaluated and a comparative quality control check was performed on obtained whole slide images. Both with default and custom settings for light microscopy, MIDI II proved to be faster, with only slightly more time required to prepare the scan and larger final file size as compared to Aperio (p < 0.001). No differences were noted in the number of out-of-focus slides per case (p = 0.75). Regarding immunofluorescence, the new scanner required longer preparation time (p = 0.001) with comparable scanning times and final file size (p = 0.169 and p = 0.177, respectively). Quality control showed differences in 3 quality features related to white background and blurriness (p < 0.001). No major discordances in the final diagnosis were recorded after comparing the report obtained with slides scanned using the two instruments, with only one case (4%) showing minor disagreement. The present report describes the experience of a hub nephropathology center adopting next generation digital pathology tools for the routine assessment of renal biopsies, highlighting the need for a complementary approach towards a philosophy of interoperability.

Optimality of the hub-spoke system: A review of the literature, and directions for future research

This paper reviews the relevant literature to answer the question if hub-spoke networks are optimal from an economic and environmental aspect. Hub-spoke networks are used to serve a large number of destinations with a high frequency. The concentration of flights and demand leads to positive economic effects: additional indirect effects come from the high number of destinations. Airlines may prefer indirect passengers over direct passengers, at the expense of local welfare, if the willingness-to-pay of the former is higher. Furthermore, indirect effects are a redistribution of the direct effect, and may lead to double counting.Empirical evidence on environmental performance is mixed. Some case studies suggest hub-spoke networks are more harmful, given aircraft technologies and load factors. Proposed climate policies increase costs of operations, likely leading to a strengthening of the hub-spoke system. Further research into network development and the effect of climate policy on airline behaviour is necessary to support climate and aviation policy.

The Washington State Hub and Spoke Model to increase access to medication treatment for opioid use disorders

IntroductionThe federal Opioid State Targeted Response (Opioid STR) grants provided funding to each state to ramp up the range of responses to reverse the ongoing opioid crisis in the U.S. Washington State used these funds to develop and implement an integrated care model to expand access to medication treatment and reduce unmet need for people with opioid use disorders (OUD), regardless of how they enter the treatment system. This paper examines the design, early implementation and results of the Washington State Hub and Spoke Model. MethodsDescriptive data were gathered from key informants, document review, and aggregate data reported by hubs and spokes to Washington State's Opioid STR team. ResultsThe Washington State Hub and Spoke Model reflects a flexible approach that incorporates primary care and substance use treatment programs, as well as outreach, referral and social service organizations, and a nurse care manager. Hubs could be any type of program that had the required expertise and capacity to lead their network in medication treatment for OUD, including all three FDA-approved medications. Six hub-spoke networks were funded, with 8 unique agencies on average, and multiple sites. About 150 prescribers are in these networks (25 on average). In the first 18 months, nearly 5000 people were inducted onto OUD medication treatment: 73% on buprenorphine, 19% on methadone, and 9% on naltrexone. ConclusionsThe Washington State Hub and Spoke Model built on prior approaches to improve the delivery system for OUD medication treatment and support services, by increasing integration of care, ensuring “no wrong door,” engaging with community agencies, and supporting providers who are offering medication treatment. It used essential elements from existing integrated care OUD treatment models, but allowed for organic restructuring to meet the population needs within a community. To date, there have been challenges and successes, but with this approach, Washington State has provided medication treatment for OUD to nearly 5000 people. Sustainability efforts are underway. In the face of the ongoing opioid crisis, it remains essential to develop, implement and evaluate novel models, such as Washington's Hub and Spoke approach, to improve treatment access and increase capacity.

Collaboration risk management in IT-enabled asymmetric partnerships: Evidence from telestroke networks

Information technology (IT)-enabled partnerships can unlock previously unattainable value propositions between organizations that have resource, capability, and other asymmetries by allowing larger organizations access to niche and local resources while providing smaller organizations access to enhanced resources and capabilities. However, recent studies have shown that many IT-enabled asymmetric partnerships often fail because the organizations do not effectively manage the involved collaboration risks. Most organizations focus on the strategic aspect of whether partners behave cooperatively or competitively, while paying scant attention to the operational aspect of bringing together partner contributions through coordination. To examine this problem, we report on a case study of two hub-spoke networks that used telemedicine to facilitate expertise sharing and decision making about stroke treatment at emergency departments in rural hospitals (spokes) based on information exchanges with remote neurologists at academic medical centers (hubs). As a result, we contribute to the inter-organizational information systems literature by explaining how organizations in IT-enabled asymmetric partnerships manage collaboration risks. We demonstrate how partners in such relationships perceive and approach strategic cooperation and operational coordination risks differently. We also explain how collaboration interactions change over time as the partners manage risks based on needs and resource endowments. Drawing on these findings, we provide guidance to organizations on how to manage sustainable IT-enabled asymmetric partnerships in general, and telestroke networks in particular.

Evaluation of hub-spoke airport networks in Sumatra island, Indonesia to increase efficiency of air transportation

Kualanamu International Airport is the busiest airport in Sumatra. In 2015, it served 8 million passengers and 41.6 thousand tons of goods for international and domestic flights. Hub-spoke networks are optimized when generally having a transport efficiency of at least 49-52% as well as providing air service in a wide geographic area and to many destinations. The aim of this study is to analyse the hub-spoke airport networks based on the Herfindahl-Hirschmann Index (HHI) to increase air transport efficiency in Sumatra Island. This study uses data from cargo production and couple’s flights from 10 airports in Sumatra Island for domestic flight route pairs and 6 airports for international flight route pairs. The results of the study show that route networks in Sumatra Island in existing conditions have not developed with the hub-spokes concept. The HHI analysis, indicates 2 hubs for domestic flights and 1 hub (Kualanamu) for international flights. Kualanamu International Airport and Hang Nadim International Airport were indicated as hub airports in Sumatra Island for domestic flights. The efficiency of air cargo transportation through the system (2 hubs and 8 spokes) results in a transport efficiency at 68.37%, which is still far above the efficient range at 49-52%.

The multi-airline p-hub median problem applied to the African aviation market

Despite growth in research on air transport in Africa in recent years, little is known about the adequacy of the infrastructure to sustain potential future air traffic expansion. The continent has experienced growth in domestic, intra- and inter-continental air traffic services over the past two decades that we project will continue over the medium term. Applying a gravity model in which corruption, conflict, common language and land-locked indices contribute to the demand estimation, we forecast annual intra-African growth of 8.1% up to 2030. As witnessed in established markets, deregulation will likely result in hub-spoke network designs in order to accommodate demand efficiently if mobility and access is to be encouraged. In this research, we modify the p-hub median problem in order to identify multiple, economically viable, hub-spoke networks that would adequately serve the intra- and inter-continental demand for air transport. Aside from current hubs, namely Cairo (Egypt), Addis Ababa (Ethiopia) and Johannesburg (South Africa), future hubs could include airports in the North that serve European-African flows, such as Algiers, and Nigeria in the West due to its relatively large population and wealth. By 2030, we also find that demand is sufficient to justify an additional hub in central Sub-Saharan Africa, such as Lusaka (Zambia). However, this would be dependent on the implementation of liberalisation policies as set out in the Yamoussoukro Decision.

Airline Pricing and Airport Charges in Hub-Spoke Networks with Congestion

This article investigates airline pricing and airport congestion charges in hub-spoke networks. When a public hub airport and two public spoke (local) airports independently levy their charges, airlines will eventually set a ticket price that overcharges the passengers for congestion delay cost and overcompensates for airline markups. Privatizing only local airports will always lead to more overcharge, whereas privatizing only the hub airport or all airports could result in lesser overcharge if the network markets are competitive. The degree of overcharge under a private hub and public local airports is always lesser than that under a public hub and private local airports, implying that privatizing a hub airport could yield higher social welfare than privatizing a local airport. Furthermore, investigation on compensation for airline markups also finds that privatizing a hub airport is preferable to privatizing a local airport. These findings have policy implications for airport privatization.

日本発着の国際コンテナ輸送におけるネットワークとハブ港の選定と評価法

The number of shipping services by very large container ships is decreasing in Japan because they are avoiding the inefficiency of picking cargos at distributed Japanese ports. On the other hand, China and Korea have concentrated their investment on a few large ports to create hub-spoke networks and to keep their influences on the physical distributions in East Asia region. This paper describes a container logistics simulation for designing of international container transportation networks. We discuss the economical benefit of concentrating international cargos in one or two major Japanese hub ports by evaluating the total shipping cost of shippers and shipping companies. The result shows the suitable selection of Japanese hub ports and its benefit to domestic and foreign shippers.

Economy of Frequency and Airline Network Structure

Recently, emerging airline companies providing frequent point-to-point (PP) flight services have proven to be more profitable than those operating hub-spoke (HS) networks. Customers can enjoy more flexibility to arrange their itinerary by choosing PP flights. The strategic complementarity appeared in customers' choices of air carriers brings about thick-market externality. In the markets where thick market externality works, more customers choose PP flights, more frequent PP flights become available. Thus, the positive feedback mechanisms could be geared in by economy of frequency. In this paper, a market equilibrium model with economy of frequency is presented to investigate the comparative advantage of PP networks over HS networks. The de-hub mechanism where PP networks takes over HS networks is also investigated.

Equilibria in Networks

We study a model in which two carriers choose networks to connect cities and compete for customers. We show that if carriers compete aggressively (e.g., Bertrand-like behavior), one carrier operating a single hub-spoke network is an equilibrium outcome. Competing hub-spoke networks are not an equilibrium outcome, although duopoly equilibria in nonhub networks can exist. If carriers do not compete aggressively, an equilibrium with competing hub-spoke networks exists as long as the number of cities is not too small. We provide conditions under which all equilibria consist of hub-spoke networks.

Entry and Exit in Hub-Spoke Networks

This paper explains why regional carriers may not survive in hub-and-spoke networks. It is suggested that when a regional carrier and a hub operator compete in a spoke market, both will suffer losses in that market. If the hub operator exists in the spoke market, its profits in connecting markets will fall. As long as the number of such markets is large enough, it is a dominant strategy for the hub operator not to exit from the spoke market, which forces the regional carrier, assuming fixed costs are not sunk, to exit.