Diffusion Stage Research Articles

Did the Roll-Out of Community Notes Reduce Engagement With Misinformation on X/Twitter?

Developing interventions that successfully reduce engagement with misinformation on social media is challenging. One intervention that has recently gained great attention is X/Twitter's Community Notes (previously known as "Birdwatch"). Community Notes is a crowdsourced fact-checking approach that allows users to write textual notes to inform others about potentially misleading posts on X/Twitter. Yet, empirical evidence regarding its effectiveness in reducing engagement with misinformation on social media is missing. In this paper, we perform a large-scale empirical study to analyze whether the introduction of the Community Notes feature and its roll-out to users in the U.S. and around the world have reduced engagement with misinformation on X/Twitter in terms of retweet volume and likes. We employ Difference-in-Differences (DiD) models and Regression Discontinuity Design (RDD) to analyze a comprehensive dataset consisting of all fact-checking notes and corresponding source tweets since the launch of Community Notes in early 2021. Although we observe a significant increase in the volume of fact-checks carried out via Community Notes, particularly for tweets from verified users with many followers, we find no evidence that the introduction of Community Notes significantly reduced engagement with misleading tweets on X/Twitter. Rather, our findings suggest that Community Notes might be too slow to effectively reduce engagement with misinformation in the early (and most viral) stage of diffusion. Our work emphasizes the importance of evaluating fact-checking interventions in the field and offers important implications to enhance crowdsourced fact-checking strategies on social media.

Usage and precept in eighteenth-century English object-clause complementisers

ABSTRACT This paper discusses the use of zero and that as connectors for object clauses in eighteenth-century English. Previous approaches have shown that the use of zero increased in late Middle English and became well-established in the second half of the sixteenth century, especially in speech-based text-types. Our own research, based on the evidence of The Parsed Corpus of Early English Correspondence, has shown that in the mid-seventeenth century zero was well beyond the mid-range stage of lexical diffusion (73%) with the five high frequency verbs to know, to think, to say, to tell and to hope. Chronologically, it has been shown that progress of the zero innovation was thwarted in the eighteenth century, which has been attributed to the effect of prescriptivism. In this paper, we intend to throw light on this issue by tracking the courses of zero and that during the eighteenth century in both usage and precept. With this purpose we rely on two sources of information. On the one hand, a precept corpus containing a selection of grammars published in Britain in 1681–1800. Usage, on the other, has been surveyed in light of the evidence of The Corpus of Early English Correspondence Extension Sampler. Our aim is to assess the existence of a correlation between usage and precept in the expression of object clauses in this period with the following objectives: i) to analyse the use and distribution of zero and that clauses among grammarians; ii) to evaluate the incidence of the phenomenon in correspondence, as an input mirroring the vernacular; and iii) to assess the role of the grammarians’ statements in the propagation of the marked conjunction over the period.

Double Vision as the Presenting Symptom of Metastatic Breast Cancer in an 83-Year-Old Lady

Breast cancer is the most common type of malignant tumor that occurs in women. Despite this, physicians report that they screen elderly patients for breast cancer less than young patients, regardless of cancer history. This case report describes an elderly patient who presented with diplopia, eyelid swelling, and restricted eye movement, leading to the discovery of a diffuse orbital tumor and Stage IV left breast carcinoma with metastases to bone, liver, and peritoneum. The patient had been told to stop mammograms years prior to her diagnosis despite her past history of uterine cancer. The case underscores the possibility of orbital metastasis from breast cancer and highlights the necessity of diligent cancer screening in elderly women.

Understanding the evolution of engagement with brand posts on social media using agent-based models

Purpose This paper aims to delineate the nature of the costs associated with the diffusion of brand posts. Since cost is an essential component of customer lifetime value, this research also aims to identify factors that impact consumer engagement (CE) with brand posts. Design/methodology/approach This study conceptualize marginal cost of CE as the ratio of a unit change in cost for a unit change in CE – this ratio is conceptualized for a paid brand post compared to an organic brand post. The authors present a theoretically grounded simulation method that analyzes the relative impact of several factors that influence CE with brand posts. By using an agent-based simulation model, the method presented in this paper helps explain the relative impact of four factors on CE with brand posts on social media. Findings The authors explain four factors that influence the diffusion of CE with a brand post – promotion-related (i.e. whether it is paid vs organic), network-related, user-related and active periods. The authors also show that the effectiveness of paid posts vs organic posts attributed to a better audience assembled by the seeding algorithms dissipates after the initial stages of diffusion. These findings indicate that paid posts are effective vs organic posts in large part due to higher exposure than due to the efficiency of the algorithms to assemble nodes that are likely to engage with the post. Research limitations/implications An agent-based model details the impact of several factors that influence the effectiveness of paid and organic posts and presents methods to analyze the impact of these factors that have implications for theory. Practical implications The authors address the difficulty in ascertaining the effectiveness of paid posts by proposing a metric – marginal cost of engagement, defined as the incremental cost incurred by the marketer in earning one additional unit of CE. Since the costs incurred on paid and organic posts differ only on variable components, the marginal cost of engagement presents a way to benchmark paid posts against organic posts, which is very useful for managers in ascertaining the amount to spend on paid posts on social media. Originality/value There is little prior research on the costs involved in the diffusion of brand posts on social media. Identifying specific factors that impact costs is valuable for theory and practice.

Diffusive Phyllosphere Microbiome Potentially Regulates Harm and Defence Interactions Between Stephanitis nashi and Its Crabapple Host.

Pear lace bug (Stephanitis nashi) is a significant herbivorous pest, harbouring a diverse microbiome crucial for crabapple (Malus sp.) host adaptation. However, the mutual influence of S. nashi- and plant-associated microbiomes on plant responses to pest damage remains unclear. This study found that S. nashi damage significantly altered bacterial community structure and reduced bacterial evenness in the crabapple phyllosphere. Notably, bacterial diversity within S. nashi was significantly lower than that in the environment, potentially influenced by insect developmental stage, bacterial diffusion stage and endosymbiont species number and abundance. Extensive bacterial correlation and diffusion effect between S. nashi and adjacent plant environments were observed, evident in a gradual decrease in bacterial diversity and an increase in bacterial acquisition ratio from soil to phyllosphere to S. nashi. Correspondingly, S. nashi significantly impacted the metabolic response of crabapple leaves, altering pathways involved in vitamin, amino acid and lipid metabolism and so forth. Furthermore, association analysis linked these metabolic changes to phyllosphere bacterial alterations, emphasizing the important role of diffusive phyllosphere microbiome in regulating S. nashi-crabapple interactions. This study highlights bacterial diffusion effect between insect and plants and their potential role in regulating insect adaptability and plant defence responses, providing new insights into plant-insect-microbiome interactions.

Dissolved organic matter-mediated adsorption behavior of benzophenones on functionalized covalent triazine frameworks

Adsorption is a highly efficacious technique for the remediation of organic micropollutants (OMPs). However, the presence of dissolved organic matter (DOM) frequently impedes adsorbent process, with insufficient attention given to this influence. This study systematically evaluates the adsorption performance of covalent triazine frameworks (CTFs) functionalized with electron-donating or electron-withdrawing groups for benzophenones (BPs). The adsorption capacities of SO3H-CTF, OH-CTF, and NH2-CTF for BPs were 512.11 μmol/g, 1356.27 μmol/g, and 1421.85 μmol/g, respectively. The adsorption mechanism is predominantly governed by π-π electron donor–acceptor (EDA) interactions, supplemented by hydrogen bonding, particularly in hydroxyl-containing BPs, with electrostatic interactions being relatively negligible. Functionalization with − OH and − NH2 groups increased the electron density in π-conjugated regions, enhancing BPs adsorption capacity, whereas − SO3H modification, due to its electron-withdrawing nature, acted as a π electron acceptor. Importantly, the mediating role of humic acid (HA) in the adsorption process was investigated. The CTF-BPs-HA ternary system can either inhibit/enhance π-π EDA interactions between π-electron donor/acceptor and BPs by adsorbing onto the CTF materials. The HA-mediated system primarily affects the film diffusion stage, with minimal impact on pore diffusion and inner surface adsorption. The oxygenated functional groups in HA slightly enhanced hydrogen bonding within the adsorption system, with negligible influence on electrostatic interactions. In the presence of HA, the overall adsorption capacity of SO3H-CTF decreased by 67.0 %, while that of OH-CTF and NH2-CTF increased by 120.9 % and 55.3 %, respectively. This study elucidates the electronic behavior modifications of functionalized CTFs during BPs adsorption and underscores the significant role of HA in interaction mechanisms, providing theoretical guidance for the design of advanced adsorbents to enhance pollutant removal efficiency.

A color image encryption algorithm based on a novel 4D hyperchaotic system and bit-level diffusion

As digital images are widely used in social media, medical, military and other fields, ensuring the privacy and security of image data has become a critical concern. Firstly, we propose a novel four-dimensional hyperchaotic system and validate that it exhibits a broad chaotic range, as demonstrated by bifurcation diagrams and Lyapunov exponent experiments. Additionally, simulated circuit diagrams verify the hardware feasibility of the proposed system. Secondly, we design a dynamic iterative scrambling (DIS) scheme that dynamically divides the image into multiple matrices for spatially indexed scrambling. Excellent substitution performance can be ensured by multiple iterations. In the diffusion stage, a multidirectional bit-level L-shaped (MDBL) scheme is proposed. Diffusion is conducted on the bit plane using a designed cross-multiplanar selection algorithm, which fuses the high and low bit planes, thereby enhancing the diffusion performance of MDBL. Thirdly, Based on the above concepts, a novel four-dimensional hyperchaotic system and an encryption algorithm based on bit-level diffusion are proposed. Finally, experimental results and security analyses demonstrate the effectiveness of the novel 4D hyperchaotic system and image encryption scheme. The proposed encryption scheme exhibits robust anti-interference capabilities and effectively safeguards image security.

Modeling and simulation of technological innovation diffusion of high-performance construction materials in transportation engineering

This study focuses on the diffusion process of technological innovations in high-performance construction materials (HPCMs) within the field of transportation engineering. The aim is to explore the impact of various factors on this process through modeling and simulation. The research employs a multi-agent modeling approach to construct a simulation model of the diffusion of technological innovations of HPCMs among firms and owners. It analyzes the impact of firms’ strategy choices, knowledge sharing, and government policies on the diffusion of technological innovations of HPCMs. Through simulation experiments, this study reveals the impact of the proportion of firms choosing followership or innovation strategies on the efficiency of technology diffusion within complex networks, as well as the double-edged effect of knowledge sharing. Additionally, the findings indicate that adjustments of government policies at different stages of diffusion have a significant impact on market dynamics. This study provides theoretical foundations and practical recommendations for promoting the research and application of high-performance construction materials, thereby advancing green and sustainable development in transportation engineering.

A molecular dynamics study on the supercritical evaporation of liquid ammonia under forced convection conditions

Although the behavior of the supercritical transition during the evaporation of liquid fuels in engine combustion chambers has been studied by many researchers, the effects of convection on the phase transition of liquid fuel in supercritical environments have been little studied. Previous studies mainly focused on hydrocarbon fuels for supercritical evaporation, with fewer on the zero-carbon liquid ammonia fuel. Aiming at the above deficiencies, this study used molecular dynamics simulations (MD) to explore the phase transition of liquid ammonia in a nitrogen supercritical environment under forced convection conditions. The Peng-Robinson equation of state (PR-EoS) was used to calculate the vapor–liquid equilibrium of the ammonia–nitrogen system to determine the supercritical transition time of liquid ammonia under forced convection conditions. The effects of forced convection on the heat and mass transfer process and the evolution of the liquid-phase region and the vapor–liquid interface region were analyzed. It was found that forced convection can promote the mass and heat transfer process and accelerate the phase transition of liquid ammonia to some extent. Forced convection may have a greater effect on the single-phase diffusive mixing process compared to the two-phase evaporation process. The increase in the interfacial thickness under forced convection conditions is mainly attributed to the temperature increase promoted by convection. The interfacial temperature dominates the development of its thickness and the thickness is approximately linear with temperature during the diffusive mixing stage. The shear effect induced by convection has an inhibitory effect on the diffusion of ammonia molecules within the interface region along the vertical convection direction. The cases in this study indicate that forced convection may promote the supercritical transition of liquid ammonia. In addition, a dimensionless number κ was proposed to explore the possibility of scaling up the MD results to the engineering scale.

A novel surface molecularly imprinted polymer based on the natural biological macromolecule sporopollenin for the specific and efficient adsorption of resveratrol from Polygonum cuspidatum extracts

Sporopollenin is a natural biological macromolecule consisting of highly cross-linked carbon, hydrogen, and oxygen atoms, with a highly porous structure and multifunctional groups. In this work, a novel surface molecularly imprinted polymer based on magnetically aminated cattail sporopollenin (MACSp-SMIP) was prepared for the specific and efficient adsorption of resveratrol, with the aim of purifying resveratrol from Polygonum cuspidatum extracts. MACSp-SMIP was found to have a porous structure covered with the multi-layered sponge-like imprinted polymers. MACSp-SMIP had a high adsorption capacity for resveratrol (65.77 mg·g−1) and excellent selectivity (imprinting factor 5.64). The adsorption of resveratrol by MACSp-SMIP was a homogeneous diffusion dominated by chemical adsorption with three stages of external diffusion, internal diffusion, and micropore diffusion. MACSp-SMIP was used as an adsorbent in molecularly imprinted solid-phase extraction for the purification of resveratrol from P. cuspidatum extracts, achieving a resveratrol recovery of 94.33 % and a purity of 76.67 % in the final products. MACSp-SMIP maintained a satisfactory recovery of resveratrol (88.18 %) after six cycles. Overall, this work developed a promising biological macromolecule-based adsorbent MACSp-SMIP for the specific and efficient adsorption of resveratrol, and also provided an efficient and simple approach for the selective purification of resveratrol from P. cuspidatum extracts for food/nutraceutical applications.

Effective application of green nano adsorbent on the removal of carbofuran from wastewater

In this study, carbofuran (CF) was eliminated from wastewater using pomegranate peel nano adsorbent (PPNA). Infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) before and after adsorption were used to assess the process efficiency. BET demonstrated that the PPNA has a specific surface area of 356.5 m2/g. The PPNA was tested under some environmental factors, such as contact time, concentration, adsorbent dose, temperature, and pH. Experimental work was done within the range of 10–50 mg/l initial concentration and the best biosorption capacities were found at 30 min contact time, 0.7 g adsorbent dose, 25 °C, and pH 2. The Freundlich isotherm was the best-fitting isotherm model. The pseudo-second-order model provided the best fit to the process kinetics and indicated that the intra-particle diffusion stage is the rate-limiting step for the process. The study of thermodynamics showed that carbofuran adsorption on PPNA was physisorption (ΔG = −3.2334 kJ/mol) and spontaneous at high temperatures (ΔH = 22.2058 kJ/mol, ΔS = 85.0355 J/mol K). Design of a single-stage batch adsorber for the adsorption of CF from aqueous liquors using PPNA was also done.

Investigation into diffusion behaviours of moisture in asphalt film using Fourier transform infrared spectroscopy

ABSTRACT To reveal the moisture damage mechanism of asphalt pavement and clarify the process of moisture damage to asphalt films, the diffusion behaviours of moisture in asphalt films were analysed. The findings indicate that during the first stage of the water bath process, the moisture diffusion coefficient in asphalt films is considerable and the diffusion rate is rapid. As the moisture diffusion rate increases, the free moisture content in asphalt films tends to saturate. Subsequently, partial free moisture transitions into bound moisture results in a decline in the diffusion coefficient of asphalt films and a reduction in its moisture absorption rate. As the temperature rises, the moisture diffusion coefficient in asphalt film and the maximum saturation amount of moisture that can be absorbed by asphalt films increase. The moisture diffusion behaviour is not readily discernible at a low temperature. The diffusion coefficients of moisture in unmodified asphalt films in the two stages are higher than those in modified asphalt films. The first stage of moisture diffusion in unmodified asphalt films occurs at a faster rate than in modified asphalt films. It is further verified that unmodified asphalt is more subjected to moisture damage.

Sustainable enhancement of fly ash-based geopolymers: Impact of Alkali thermal activation and particle size on green production

Addressing the challenges posed by the slow reactivity of fly ash (FA) with alkali at ambient temperatures, this study delves into the enhancement of FA-based geopolymers through alkali thermal activation (ATA). The ATA process, conducted at 550°C for 1 h, significantly increases the availability of reactive silica and alumina, which are essential for geopolymerization. A critical focus of the research is the influence of FA particle size on ATA’s efficacy and the resultant mechanical properties of the geopolymers. Findings reveal that the ATA process facilitates the rapid dissolution of the vitreous phase in FA. This leads to a sequential release of silica and alumina, which is pivotal for the geopolymer’s matrix development. Notably, geopolymers synthesized from finely milled FA, post-ATA, demonstrate a marked increase in compressive strength, escalating from 30.51 MPa to an impressive 38.46 MPa. The study meticulously delineates geopolymerization into four distinct stages—initial dissolution, depolymerization, geopolycondensation and gelation, and final diffusion, with the initial dissolution and final diffusion stages being paramount in defining the reaction kinetics and the ultimate strength of the geopolymer. This enhanced understanding paves the way for optimizing FA utilization in geopolymers, promising a more sustainable and efficient pathway for producing construction materials with superior mechanical properties.

Heat-dependent properties of methane diffusion in coal: an experimental study and mechanistic analysis.

Coalbed methane thermodynamic extraction, as an emerging ECBM recovery method, can effectively improve gas recovery rates. And clarifying methane diffusion and migration law in coal under thermal stimulation is crucial for the selection of its process parameters. Based on laboratory methane adsorption-release experiments, the evolution law of methane diffusion characteristics with temperature and pressure was studied, and the control mechanism of heat-dependent methane diffusion behavior was explored. The results show that both thermal stimulation and high adsorption pressure accelerated the methane diffusion rate in coal. Adsorption pressure had little effect on methane diffusion percentage, but thermal stimulation promoted a significant increase in diffusion percentage and improved the net methane yield. The influence mechanisms of adsorption pressure and thermal stimulation on methane diffusion characteristics are elucidated in relation to the amount and proportion of methane-activated molecules in the diffusion process. The constant diffusion coefficient of methane is heat-dependent, based on which a diffusion model is derived to accurately predict the methane release process in coal. Additionally, temperature has a more important effect on transient diffusion coefficient than pressure. Thermal stimulation leads to a net increase rather than a decrease in diffusion coefficient in the early diffusion stages and can also accelerate the attenuation of diffusion coefficient, with this intensifying effect becoming more pronounced at higher temperatures. The research results can provide some reference for the determination of coal seam gas content and the selection of heat injection process parameters.

Investigation and CFD simulation of coal dust explosion accident in confined space: A case study of Gaohe Coal Mine Ventilation Air Methane oxidation power plant

The study investigates a coal dust explosion accident within a confined space in Shanxi. The accident was caused by coal dust coming into contact with a high-temperature heat source under the influence of the stack effect. Based on the investigation of the coal dust explosion accident, the study uses computational fluid dynamics (CFD) simulation to reconstruct the accident scenario. The simulation results provide a detailed depiction of coal dust movement within subsurface semi-enclosed confined spaces during the ventilation diffusion stage, influenced by the stack effect, and confirm the formation of a coal dust layer at the heat source due to coal dust deposition. The simulation results of the two explosion processes indicate that excessively high coal dust concentrations within confined spaces have a negative correlation with the development of explosion flames and the peak overpressure. It resulted in a secondary explosion with a relatively low concentration of coal dust, where the peak overpressure was five times that of the primary explosion. Comparative analysis between simulation results and actual investigations the accuracy of the CFD simulation in capturing the accident process and its characteristics, providing valuable insights for preventing and controlling coal dust explosion accidents.

ACM and rectangular images: Overlapping partitions, implementation, and periodicity analysis.

The Arnold Cat Map (ACM) is a popular chaotic map used in image encryption. Chaotic maps are known for their sensitivity to initial conditions and their ability to permute, or rearrange, pixels. However, ACM is periodic, and its period is relatively short. This periodicity decreases the effective key-space and security of a cryptosystem using ACM. Further, ACM is typically only able to be performed on square images. To solve the low periodicity and typical limitation to square images, this paper proposes performing ACM on overlapping square partitions which cover the entirety of an image. The presence of overlap results in a greatly increased image period. The resulting system will be referred to as overlapping ACM or OACM. Several papers have already discussed systems involving overlapping ACM. However, they did not discuss the implementation or periodicity of such a system in detail. This paper does cover the implementation and periodicity analysis of OACM and proposes a simple symmetric encryption system which uses OACM. The proposed encryption system is not as sophisticated or secure as other modern encryption schemes, since it is mainly intended as an initial test of OACM's utility. Histogram and sensitivity analyses did however indicate a level of security against various cryptographic attacks, and OACM performed reasonably in both the permutation and diffusion stages of the cryptosystem.

Diffusion mechanism of quick-setting slurry in water-rich fractured rock mass based on circle-outburst diffusion model

Grouting is the most commonly used methods in dealing with water inrush issue in mine and tunnel engineering. In order to better predict the grouting effect, research on slurry diffusion mechanism became a hotspot for scholars. At present, the mainstream theoretical model used to study the slurry diffusion mechanism are the circle diffusion model and the modified ones in plane plate fracture. However, these models cannot explain the “contradiction” between the rapid setting characteristics of quick-setting slurry and the continuous long-term injection of slurry in grouting engineering, which cannot accurately predict the grouting pressure or grouting diffusion range. Therefore, a “circle-outburst diffusion model” which can explain the above “contradiction” was proposed in this paper. Based on the new model, stepwise algorithms were developed to predict the grouting pressure and slurry diffusion range. By means of conducting fracture grouting simulation test and collecting grouting pressure data in an actual grouting project, the new model was verified and the slurry diffusion mechanism was studied. Comparison results indicate that the new model can reveal the intrinsic reason for the irregular diffusion phenomenon of the slurry and forecast the outburst moment accurately. The circle diffusion stage and outburst diffusion stage elaborated in the new “circle-outburst diffusion model” were consistent with the staged characteristics of the grouting process presented in the grouting simulating test. Differences between theoretical and experimental pressure value were within 10 %, indicating a high degree of consistency. The number and distribution of outburst diffusion points determine slurry diffusion form and significantly influence the diffusion range. The grouting pressure and the length of slurry flow path increase nonlinearly with time in each diffusion stage. It is hoped that the new model can provide a theoretical basis for the study of diffusion mechanism of quick-setting slurry.

Brownian particle diffusion in generalized polynomial shear flows.

This study presents a mathematical framework for calculating the diffusion of Brownian particles in generalized shear flows. By solving the Langevin equationsusing stochastic instead of classical calculus, we propose a mathematical formulation that resolves the particle mean-square displacement (MSD) at all timescales for any two-dimensional parallel shear flow described by a polynomial velocity profile. We show that at long timescales, the polynomial order of time of the particle MSD is n+2, where n is the polynomial order of the transverse coordinate of the velocity profile. We generalize the method to resolve particle diffusion in any polynomial shear flow at all timescales, including the order of particle relaxation timescale, which is unresolved in current theories. Particle diffusion at all timescales is then studied for the cases of Couette and plane Poiseuille flows and a polynomial approximation of a hyperbolic tangent flow while neglecting the boundary effects. We observe three main stages of particle diffusion along the timeline for Couette and plane Poiseuille flows and four main stages for hyperbolic tangent flow. The particle MSD is distinctly different across these stages due to different dominant physical mechanisms. Thus, higher temporal and spatial resolution for diffusion processes in shear flows may be realized, suggesting a more accurate analytical approach for the diffusion of Brownian particles.

Experiential tourism and community narratives: Non-Tourist Guidebook of Ussita

In recent decades, experiential tourism studies have developed strongly within a transforming tourism development paradigm. The enhancement of the territory is more focused on its intangible resources, and experience becomes a strategic concern within a renewed way of practicing tourism where individuals look primarily for what to experience. Tourism becomes an opportunity to create and exchange experiences by challenging conventional tourism practices and advocating new value references and new forms of tourism including experiential tourism. This article will focus on the relationship between experiential tourism and community narratives: the Non tourism Project, and particularly the Non tourism Guidebook of Ussita, a small Italian municipality in an inland area and an earthquake victim, will be presented. Non tourism is a way of understanding the encounter between a community and those from outside: the non tourist seeks an intimate and authentic relationship with a territory and the community rediscovers its identity through a collective narrative. The paper aims to investigate whether community narratives can help transform tourism into an enriching and meaningful experience, creating deep bonds between tourists and the places they visit, promoting sustainability, and enhancing local cultural heritage. The non-tourist guide, as a result of the local community’s collective storytelling experience, brings tourists closer to experiential ways of visiting and has enabled the local community to rediscover its identity through the use of narrative practices. This article aims to highlight how non-tourist guides can also be a tool for dialogue between tourists and the community through the proposal of experiential itineraries. The experience of non-tourist guides is purely Italian and is at an early but interesting stage of diffusion, with volumes covering both urban contexts and smaller and inland territories. The article is the result of an initial exploratory work (Yin, 2017) that offered a preliminary understanding of the opportunity that non-tourist guides have to promote sustainability, enhancing local resources and offering significant benefits to both tourists and host communities.

Harris Hawk optimization driven adaptive image encryption integrating Hilbert vibrational decomposition and chaos

Image encryption is a technique used to protect the confidentiality of digital images. Existing encryption algorithms use chaotic maps for generating random sequences. These sequences purely depend on the fixed initial parameters, which are not adaptive to different input images, thereby limiting their ability to produce the best-possible encrypted image. This paper introduces a new Harris Hawk optimization (HHO) based adaptive image encryption algorithm that integrates Hilbert vibrational decomposition (HVD), and multiple chaotic maps. The new fitness function is specifically designed to optimize the security and robustness of the encrypted image, considering statistical and differential attack parameters (NPCR, UACI, Entropy, and correlation coefficient values). HHO is used to optimize the initial parameters of chaotic maps (Henon map, Duffing map, Lorenz equation) subject to variations in the input image. In the confusion stage, the input image is decomposed into four components of same dimension but decreasing energy using HVD. Subsequently, the block based pixel scrambling is performed on alternate components using the Henon map and Duffing map. In the diffusion stage, the image from the confusion stage undergoes a first level diffusion by bitwise XOR operation with a random image generated from the Lorenz equation. Further, second level of diffusion is achieved with a complex operation generated image from the input image, enhancing its adaptability. Finally, Arnold Cat map having number of iterations determined by the input image is used for final pixel permutation to produces the encrypted image. The optimized initial parameters and input image dependent confusion and diffusion operations enable the encryption system to adapt to changes in the input image, thereby enhancing its resistance against known plain text and known cipher text attacks. Moreover, the integration of HVD with multiple chaotic maps makes the scheme more complex to decrypt with plain text attacks. The performance of proposed algorithm is evaluated on five standard test images in terms of security and quality measures. Experimental results exhibit statistical and differential attack parameters close to ideal values (with Max. Entropy≈7.9996, Min. CC≈ 10−5, Max. NPCR≈99.64, Max. UACI≈33.62). The use of multiple chaotic maps at different stages makes the key space larger. Robustness analysis demonstrates the algorithm's capability in withstanding noise and image enhancement attacks. The comparison with state of the arts metaheuristic based and classical encryption algorithms highlights the superior performance of proposed HHO driven algorithm. The significant improvement in security parameters and overall fitness compared to fixed initial parameters is achieved by optimizing the encryption process.