A Catalan word of length n is defined as a word w = w(1)w(2) & centerdot; & centerdot; & centerdot; w(n) over the set of positive integers such that w(1) = 1 and 1 < w(j+1) < w(j) + 1 for j = 1, 2, ... , n-1. Catalan words may be represented geometrically as bargraphs. An l-peak (resp. l-valley) is an occurrence of a subword ablc, where l > 1 and b is greater (resp. less) than both a and c. In this paper, we introduce the notion of order i for peaks and valleys, defined as the difference i = a-c, and study (l,i)-peaks and (l,i)-valleys in Catalan words. We derive generating functions tracking the number of (l,i)-peaks and (l,i)-valleys for arbitrary sets of values of l and i, with respect to word length. The method employs the (standard) bijection from these Catalan words to Dyck paths of semilength n. (c) 2026 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Cruise tourism sustainability discourse prioritises vessel level innovation, marginalising destination level social ecological impacts. To address this, we develop a structured literature based conceptual model of cruise mobility as a coupled global and local social ecological system. Supported by AI assisted extraction and synthesis of multidisciplinary literature, this paper constructs a governance-oriented framework. The analysis identifies two interacting dynamics: a reinforcing expansion loop where revenues stimulate infrastructure and deepen dependency, and a degrading acceptance loop where cumulative stress erodes tolerance. Presented as heuristic formalisation devices, these loops help explain why vessel efficiency alone cannot prevent destination level degradation. We translate these findings into a five-pillar governance framework featuring capacity thresholds, social monitoring, economic diversification, power rebalancing, and multi-level coordination. This shifts attention from ship focused compliance towards destination embedded sustainability governance.
The environmental footprint of maritime transport, combined with growing social and regulatory pressure to tackle pollution, has brought the shipping industry to the forefront of the sustainability agenda. The role of industry clusters is becoming increasingly relevant to this discourse, given their influence across all dimensions of sustainability. Surprisingly, although this profound relationship is well documented, it has not received sufficient scholarly attention. This study analyses the highly fragmented literature on maritime clusters and sustainability using a novel combination of bibliometrics and Artificial Intelligence (AI)-driven thematic analysis. On this basis, a framework is developed that captures the interaction between clusters and the key components of sustainability. The findings suggest that sustainability should not be treated as an isolated strategic initiative or the outcome of regulatory pressure, but as a key dimension of cluster competitiveness. Additionally, it emerges that digital innovation acts as a cross-cutting enabler of sustainability in maritime clusters, linking the economic, social/governance, and environmental pillars of the proposed framework. Overall, this study provides actionable insights for maritime practitioners and policy makers alike.
How do geopolitical risk shocks affect household transport consumption, and does consumer sentiment mediate this effect? We examine this question using a SVAR model and Australian data from 2013 to 2025. We identify the direct and indirect effects of geopolitical risk using hypothetical impulse responses that shut down the sentiment channel. The results show that geopolitical risk shocks increase the household transport consumption ratio overall. While geopolitical risk shocks reduce consumer sentiment, which in turn has a negative indirect effect on transport consumption, the positive direct effect of geopolitical risk more than offsets this indirect effect, resulting in a net increase in transport consumption. State-level evidence further shows that the sentiment channel is weaker in resource-exporting states, particularly Western Australia and Queensland. We also construct a directional geopolitical risk spillover index for Australia within the Indo-Pacific region using the Diebold–Yilmaz connectedness framework. We also find that geopolitical risk spillovers from other Indo-Pacific countries to Australia have a stronger effect through consumer sentiment than spillovers from Australia to other countries. Overall, the findings highlight the importance of distinguishing between direct and sentiment-mediated channels when assessing the effects of geopolitical risk on household transport consumption.
The integration of social sustainability clauses into port terminal concession agreements is essential for fostering a more inclusive, balanced, and resilient framework for port operation and development. Such integration addresses the needs of both external and internal stakeholders, namely local communities and society at large, as well as port employees who seek to safeguard their interests. This paper examines how negative externalities can be mitigated or minimized, and how positive externalities can be reinforced, through the inclusion of social sustainability measures and monitoring mechanisms within concession frameworks. Building upon an analytical review of existing literature, available concession agreements and guidelines for port concessions, as well as relevant best practices, the paper identifies and classifies a comprehensive set of social sustainability indicators applicable to the port sector. The results of the analysis are presented through two categories of indicators: external indicators, encompassing stakeholder engagement, community development, and participation of society in economic benefits; and internal indicators, covering employment conditions, training, diversity, occupational health and safety, and the working environment. These indicators, aggregated and structured for the first time within the context of port literature, form a scientific foundation for embedding social sustainability considerations into concession agreements.
