Neighbor Effects Research Articles

A contingent diffusion model of local climate change policy adoption: Evidence from Southern California cities

Climate change policy is an essential driver of urban sustainability, yet minimal research has examined how they emerge and spread across cities in shared metropolitan areas. While policy diffusion or policy mobility theories could explain the aforesaid, much of the international scholarship have not utilized an amalgamation of these two complementary theoretical perspectives. As a result, we lack a comprehensive understanding of the regional dynamics and spillover effects local governments can generate for urban sustainability. This article proposes a contingent diffusion model to examine the intra-regional adoption of local climate action plans within Southern California from 2000 to 2018. We find that neighboring jurisdictions that adopt climate policy increase the likelihood of a home city's adoption. Yet, neighboring effect is contingent on the home city's existing pro-environmental policy propensity. However, in contrast to conventional wisdom, this study finds no evidence that local environmental advocacy groups play a crucial role in the diffusion of municipal climate initiatives. Altogether, the results suggest that a regional diffusion model of policy innovations is more likely successful when adaptive capacity is in place to facilitate green infrastructure. These findings provide implications for policymakers and planners who want to achieve successful spillovers of urban climate policies across local governments.

A Contingent Diffusion Model of Local Climate Change Policy Adoption: Evidence from Southern California Cities

Climate change policy is an essential driver of sustainability, yet minimal research has examined how they emerge and spread across cities in shared metropolitan areas. While policy diffusion or policy mobility theories could explain the aforesaid, much of the international scholarship have not utilized an amalgamation of these two complementary theoretical perspectives. As a result, we lack a comprehensive understanding of the regional dynamics and spillover effects local governments can generate for urban sustainability. This article proposes a contingent diffusion model to examine the intra-regional adoption of local climate action plans within Southern California from 2000 to 2018. We find that neighboring jurisdictions that adopt climate policy increase the likelihood of a home city’s adoption. Yet, neighboring effect is contingent on the home city’s existing pro-environmental policy propensity. In contrast to conventional wisdom, this study finds no evidence that local environmental advocacy groups play a crucial role in the diffusion of municipal climate initiatives. Altogether, the results suggest that a regional diffusion model of policy innovations is more likely successful when adaptive capacity is in place to facilitate green infrastructure. These findings provide implications for urban policymakers who want to achieve successful spillovers of urban climate policies across local governments.

Densely Packed Tethered Polymer Nanoislands: A Simulation Study.

COordinated Responsive Arrays of Surface-Linked polymer islands (CORALS) allow for the creation of molecular surfaces with novel and switchable properties. Critical components of CORALs are the uniformly distributed islands of densely grafted polymer chains (nanoislands) separated by regions of bare surface. The grafting footprint and separation distances of nanoislands are comparable to that of the constituent polymer chains themselves. Herein, we characterize the structural features of the nanoislands and semiflexible polymers within to better understand this critical constituent of CORALs. We observe different characteristics of grafted semiflexible polymers depending on the polymer island’s size and distance from the center of the island. Specifically, the characteristics of the chains at the island periphery are similar to isolated tethered polymer chains (full flexible chains), while chains in the center of the island experience the neighbor effect such as chains in the classic polymer brush. Chains close to the edge of the islands exhibit unique structural features between these two regimes. These results can be used in the rational design of CORALs with specific interfacial characteristics and predictable responses to external stimuli. It is hoped that this the discussion of the different morphologies of the polymers as a function of distance from the edge of the polymer will find applications in a wide variety of systems.

Effects of above- and below-ground herbivore interactions on interspecific relationship between the invasive plant Alternanthera philoxeroides and its native congener Alternanthera sessilis

Biological invasion is a major threat to global biodiversity. The relative interspecific competition abilities of invasive species compared to those native species determine their invasion success. In this study, we examined the effects of the specialist leaf beetle Agasicles hygrophila and the nematode Meloidogyne incognita on the growth and interspecific relationship between the invasive plant Alternanthera philoxeroides and its native congener A. sessilis. Compared without herbivory, nematode herbivory alone significantly reduced shoot height of A. sessilis by 28.1%, but conversely significantly increased the shoot height of A. philoxeroides by 52.8% and aboveground biomass of A. sessilis by 63.7%. Beetle herbivory alone significantly reduced shoot height of A. sessilis by 40.7%, but did not affect that of A. philoxeroides. The combination of beetle and nematode herbivory significantly reduced shoot height of A. sessilis by 35.3% as well as the belowground biomass of A. philoxeroides by 62.2%, but significantly increased the aboveground biomass of A. sessilis by 69.1%. Herbivore stress did not affect stem diameter, branch number, and root length of both species. The relative neighbor effect index (RNE) of the two species without herbivory were positive, and the RNE value of A. philoxeroides was 21.3% higher than that of A. sessilis. However, the RNE values of A. philoxeroides were negative under all above- and below-ground herbivory treatments. The RNE values of A. sessilis were positive under the beetle or the nematode herbivory alone and negative under the beetle + nematode herbivory combination. These results indicated that above- and below-ground herbivore interactions could change the interspecific relationship between the two species, and in turn might accelerate the invasion of A. philoxeroides.

Palladium-Catalyzed Nucleophilic Isocyanation for the Synthesis of α-Aryl-α-Isocyanoacetoamide Derivatives

Abstract α-Aryl-α-isocyanoacetoamide derivatives were synthesized through palladium-catalyzed nucleophilic isocyanation. Diethylphosphates derived from N,N-disubstituted mandelamide derivatives reacted with trimethylsilyl cyanide in the presence of a catalytic amount of Pd(OAC)2 to afford the titled isonitriles (13 examples) in moderate to high yield. The silyl cyanopalladate complex formed in situ was a proposed catalyst, which behaved as a Lewis acid promoting elimination of the phosphate group and also the N-nucleophilic cyanide reagent. The isocyanation was applied to a gram-scale reaction with 0.2 mol% of the catalyst. The obtained isocyanoacetoamide was employable for the further transformation into the trisubstituted oxazole without any purification procedure. DFT calculation suggested that the neighboring group effect of the carbonyl moiety in the substrate amide group assisted the elimination of phosphate and stabilized the carbocation intermediate. A plausible reaction mechanism of the isocyanation is also described.

Species patch size at seeding affects the productivity of mixed legume-grass communities

The impact of inter- and intraspecific neighboring plants on mixed legume-grass communities has rarely been explored in relation to seeded species patch size. In this study, two native perennial species, the legume alfalfa (Medicago sativa L.) and the grass tall fescue (Festuca arundinacea L.), were investigated as monocultures and in mixture. A three-year growth experiment was conducted to investigate the effects of plant-plant competitive interactions on fine-scale seeding patterns: monoculture, three different conspecific patch sizes (1.0, 0.5, and 0.25 m side length of squares) and a control in which the seeds were mixed and scattered (i.e., patches were not formed) as in conventional seeding. The results demonstrated significant differences in the mutual effect intensity in all conspecific patch sizes, indicating the presence of grass-legume interactions on mixed plant communities. Smaller patch sizes resulted in better facilitation by higher neighbor effect intensity when compared with a larger patch size and the conventional mixture. Seedings in the smallest patch size of 0.25 m × 0.25 m showed intra- and interspecific competition and significantly improved aboveground productivity compared with the other patch sizes. We directly quantified the variation of species neighbor effect intensity between grass and legume mixtures among different species patch sizes at seeding. Integrating this knowledge into species interaction models in plant community ecology could greatly enhance our understanding of species coexistence in grasslands as well as provide opportunities for manipulating competition to achieve specific agronomic aims.

An inquiry into the regional unemployment disparities in Tunisia: a spatial Durbin model

ABSTRACT This study uses a spatial Durbin model in identifying possible causes of the overdispersion into regional unemployment in Tunisia. Data properties were identified using exploratory spatial data analysis which indicates significant neighbouring effects for several variables. Differences in socio-economic structure between regions explain in part these phenomena. Education is a key factor and also some constraints prevent married women from taking up jobs, thus exacerbating regional unemployment. Regions with important tourism activity do well than others. Tourism sector exhibit important spillover effects on regional unemployment while the impact of agricultural activity is confined to local labour market. The diversification of the industrial fabric at a regional level is not a sine qua non for differences reduction in regional unemployment rates. Developing road infrastructure helps to reduce unemployment disparities.

Neighbourhood-based evidence of tree diversity promotion by beech in an old-growth deciduousconiferous mixed forest (Eastern Carpathians)

Neighbourhood models are useful tools for understanding the role of positive and negative interactions in maintaining the tree species diversity in mixed forests. Under such a presumption, we aimed at testing several hypotheses concerning the mechanisms of autogenic species coexistence in an old-growth, beech-fir-spruce stand, which is part of the Slătioara forest reserve (Eastern Carpathians). Univariate/bivariate spatial point pattern analyses, the individual tree species-area relationship, the species mingling analysis and generalised linear mixed models of neighbour interference were applied on data concerning the position and allometry of all saplings and trees occurring within a 0.24 ha plot. The monospecific distribution of either beech or spruce saplings did not support the spatial segregation hypothesis. There was no evidence of conspecific negative distance dependence, as no spatial segregation was detected between the saplings and trees of any species. Within 4 m-neighbourhood, the beech saplings appeared as diversity accumulators, which might be indicative of indirect facilitation (e.g., herd protection hypothesis). At tree stage, none of the three species showed either accumulator or repeller patterns in their neighbourhood with respect to sapling species richness. Signals of positive and negative interspecific association were found in tree-sized beech (at scales of 10 to 20 m) and spruce (at scales of 4 to 17 m), respectively. The former, highly interspersed pattern is in accordance with the hypothesis of positive complementary effects, whereas the latter, poorly intermingled pattern is probably linked to the unexpected, positive neighbouring effect of spruce trees on the stem growth of their conspecific saplings. Such self-favouring process might be due to a facilitative below-ground mechanism. Conversely, the beech saplings were suppressed through interference from the neighbouring conspecific trees. The beech appears to be the key promoter of tree species coexistence in the study forest stand, in contrast to the low interspersion of spruce in the overstorey leading to lower local tree diversity.

Neighbourhood-based evidence of tree diversity promotion by beech in an old-growth deciduous-coniferous mixed forest (Eastern Carpathians)

Neighbourhood models are useful tools for understanding the role of positive and negative interactions in maintaining the tree species diversity in mixed forests. Under such a presumption, we aimed at testing several hypotheses concerning the mechanisms of autogenic species coexistence in an old-growth, beech-fir-spruce stand, which is part of the Slatioara forest reserve (eastern Carpathians). Univariate/bivariate spatial point pattern analyses, the individual tree species-area relationship, the species mingling analysis and generalised linear mixed models of neighbour interference were applied on data concerning the position and allometry of all saplings and trees occurring within a 0.24 ha plot. The monospecific distribution of either beech or spruce saplings did not support the spatial segregation hypothesis. There was no evidence of conspecific negative distance dependence, as no spatial segregation was detected between the saplings and trees of any species. Within 4 m-neighbourhood, the beech saplings appeared as diversity accumulators, which might be indicative of indirect facilitation (e.g., herd protection hypothesis). At tree stage, none of the three species showed either accumulator or repeller patterns in their neighbourhood with respect to sapling species richness. Signals of positive and negative interspecific association were found in tree-sized beech (at scales of 10 to 20 m) and spruce (at scales of 4 to 17 m), respectively. The former, highly interspersed pattern is in accordance with the hypothesis of positive complementary effects, whereas the latter, poorly intermingled pattern is probably linked to the unexpected, positive neighbouring effect of spruce trees on the stem growth of their conspecific saplings. Such self-favouring process might be due to a facilitative below-ground mechanism. Conversely, the beech saplings were suppressed through interference from the neighbouring conspecific trees. The beech appears to be the key promoter of tree species coexistence in the study forest stand, in contrast to the low interspersion of spruce in the overstorey leading to lower local tree diversity.

Covalent Adaptable Networks Using β-Amino Esters as Thermally Reversible Building Blocks.

In this study, β-amino esters, prepared by the aza-Michael addition of an amine to an acrylate moiety, are investigated as building blocks for the formation of dynamic covalent networks. While such amino esters are usually considered as thermally nondynamic adducts, the kinetic model studies presented here show that dynamic covalent exchange occurs via both dynamic aza-Michael reaction and catalyst-free transesterification. This knowledge is transferred to create β-amino ester-based covalent adaptable networks (CANs) with coexisting dissociative and associative covalent dynamic exchange reactions. The ease, robustness, and versatility of this chemistry are demonstrated by using a variety of readily available multifunctional acrylates and amines. The presented CANs are reprocessed via either a dynamic aza-Michael reaction or a catalyst-free transesterification in the presence of hydroxyl moieties. This results in reprocessable, densely cross-linked materials with a glass transition temperature (Tg) ranging from -60 to 90 °C. Moreover, even for the low Tg materials, a high creep resistance was demonstrated at elevated temperatures up to 80 °C. When additional β-hydroxyl group-containing building blocks are applied during the network design, an enhanced neighboring group participation effect allows reprocessing of materials up to 10 times at 150 °C within 30 min while maintaining their material properties.

A Socially Aware Huff Model for Destination Choice in Nature-based Tourism

Abstract. Identifying determinants of tourist destination choice is an important task in the study of nature-based tourism. Traditionally, the study of tourist behavior relies on survey data and travel logs, which are labor-intensive and time-consuming. Thanks to location-based social networks, more detailed data is available at a finer grained spatio-temporal scale. This allows for better insights into travel patterns and interactions between attractions, e.g., parks. Meanwhile, such data sources also bring along a novel social influence component that has not yet been widely studied in terms of travel decisions. For example, social influencers post about certain places, which tend to influence destination choices of tourists. Therefore, in this paper, we propose a socially aware Huff model to account for this social factor in the study of destination choice. Moreover, with fine-grained social media data, interactions between attractions (i.e., the neighboring effects) can be better quantified and thus integrated into models as another factor. In our experiment, we calibrate a model by using trip sequences extracted from geotagged Flickr photos within two national parks in the United States. Our results demonstrate that the socially aware Huff model better simulates tourist travel preferences. In addition, we explore the significance of each factor and summarize the spatial-temporal travel pattern for each attraction. The socially aware Huff model and the calibration method can be applied to other fields such as promotional marketing.

Competitive drivers of interspecific deviations of crown morphology from theoretical predictions measured with Terrestrial Laser Scanning

AbstractTree crown morphology is a key driver of forest dynamics, determining not only the competitiveness of an individual but also the competitive effect exerted on neighbouring trees. Multiple ecological theories, including metabolic scaling theory (MST), predict crown morphology from first principles, but typically lack consideration of competition. The accurate quantification of crown morphology to test theoretical predictions, and the canopy interactions that could alter them, has historically been limited by the simplicity and associated error of traditional crown measurements.In this study, we calculate high‐resolution two‐ and three‐dimensional crown metrics from Terrestrial Laser Scanning data for 1,441Pinus sylvestris,P.nigra,Quercus fagineaandQ. ilextrees from a water‐limited forest community in central Spain and test height‐crown metric scaling relationships. We demonstrate new TLS methods to define symmetric and asymmetric neighbourhood metrics based on tree height, crown size and neighbour projected crown area, and test the importance of neighbourhood genus diversity on crown morphology by separating competition from congeneric and heterogeneric neighbours.Competition negatively impacted all crown metrics except crown depth where onlyP.nigrashowed sensitivity. Asymmetric competition was the strongest driver of pine crown morphology, but oaks were more sensitive to symmetric competition, in line with shade tolerance expectations. Congeneric competition reducedQ.fagineacrown size and changed its shape, but we found no significant effects of heterogeneric neighbours. Most species and crown dimensions had height‐crown scaling exponents below those predicted by MST, which may be due to water limitation effects. Pines and oaks showed large differences in crown depth to height scaling, with the former shallower and the latter deeper, in contrast to theoretical predictions.Synthesis. Our study is the first to demonstrate the ability of TLS to characterise crown morphology from leaf‐wood separated clouds and competitive neighbour effects in a water‐limited forest community, and to use TLS metrics to test ecological crown scaling theory. Most crown metrics scaled below theoretical predictions. Pines were more sensitive to competition by larger neighbours and oaks to crowding from all neighbours, with competition from neighbours of the same genus having a consistent negative effect.

Intraspecific pod and seed trait variation of two herbaceous legume seeds in response to competing neighbours and nutrient resource abundance

The presence of competing neighbours can exert pressure on parent plants, forcing them to adjust their reproductive strategies to maximize recruitment success (adaptive response); however, competitive neighbour effects may be suppressed if more nutrient resources are made available (passive response). In this study, we investigated if the response of some measured seed and pods traits of Lablab purpureus and Mucuna pruriens (focal plants) were adaptively determined by the presence of competitive neighbour species (using Megathyrsus maximus as the focal neighbour) or passively determined by nutrient resource availability. We measured four pod traits (pod weight, pod length, pod filling, and no of pods/ha) and eight seed traits (no of seeds/ha, seed mass, seed yield, dry matter content, Calcium content, Phosphorus content, Nitrogen content, and seed germination percentage) of the focal plants established as mixtures (neighbour treatment) or as monocultures (no-neighbour treatment) at different levels of phosphorus fertilizer application (0, 20, and 40 kg/ha applied on treatment basis). The data were analyzed using a linear mixed-effect model. Results showed that plant identity modified competitive neighbour and nutrient resource availability effects. Competitive neighbour species facilitated increased pod length response, but suppressed pod filling and number of pods/ha which were passively improved at higher levels of nutrient abundance. The no of seeds/ha and seed yield were also passively improved at higher levels of nutrient abundance, previously suppressed by competitive neighbour effects. The presence of focal neighbours and nutrient resource levels interacted positively to increase the Phosphorus content, Nitrogen content, and seed germination %. Other measured traits were not influenced by competitive neighbour effects or nutrient resource availability. In conclusion, competitive neighbour effects on the seeds and pod traits of the focal plants depended on plant identity and nutrient resource availability. Passive trait responses may magnify competitive effects on progenies after successful recruitment.

Multi-information embedding based entity alignment

Entity alignment refers to discovering two entities in different knowledge bases that represent the same thing in reality. Existing methods generally only adopt TransE or TransE-like knowledge graph representation learning models, which usually assume that there are enough training triples for each entity, and entities appearing in few triples are easily misaligned. In this paper, we propose a multi-information embedding based entity alignment method (MEEA), which utilizes embedding methods based on multi-information, including triple embedding and neighbor information embedding, to obtain the vector representations of each entity, which are then used for aligning entities. In addition, we propose a weighted neighbor information encoding method to make the neighbor information based vector representation suitable for entity alignment, which measures the effects of different neighbors on entity alignment from three aspects (i.e., the mapping cardinality of the neighbor, the relation association of the neighbor, and the attention mechanism) and gives corresponding weights. Experiments are conducted on two cross-lingual knowledge bases, and the experimental results show that MEEA is able to yield a better performance compared to the state-of-the-art methods.

Apoptotic body-mediated intercellular delivery for enhanced drug penetration and whole tumor destruction.

Chemotherapeutic nanomedicines can exploit the neighboring effect to increase tumor penetration. However, the neighboring effect is limited, likely by the consumption of chemotherapeutic agents and resistance of internal hypoxic tumor cells. Here, we first propose and demonstrate that apoptotic bodies (ApoBDs) could carry the remaining drugs to neighboring tumor cells after apoptosis. To enhance the ApoBD-based neighboring effect, we fabricated disulfide-linked prodrug nanoparticles consisting of camptothecin (CPT) and hypoxia-activated prodrug PR104A. CPT kills external normoxic tumor cells to produce ApoBDs, while PR104A remains inactive. The remaining drugs could be effectively delivered into internal tumor cells via ApoBDs. Although CPT exhibits low toxicity to internal hypoxic tumor cells, PR104A could be activated to exert strong cytotoxicity, which further facilitates deep penetration of the remaining drugs. Such a synergic approach could overcome the limitations of the neighboring effect to penetrate deep into solid tumors for whole tumor destruction.

Singing in a fragmented landscape: wrens in a tropical dry forest show sex differences in the effects of neighbours, time of day, and time of year

Songbird vocalizations serve diverse functions including territory defence against neighbouring conspecific animals. In tropical and south-temperate regions, it is commonplace for both female and male songbirds to sing solo songs and coordinated vocal duets to defend their territories. The Area de Conservacion Guanacaste in Costa Rica is the site of an ambitious conservation effort to protect and regrow tropical dry forests; it consists of a mosaic of regenerating and mature forest patches, presenting a special opportunity to study the effect of different numbers of neighbours on male and female wrens living in these fragmented forests. We analyzed recordings of Rufous-and-white Wrens (Thryophilus rufalbus) over a 17-year period, focusing on vocal behaviour and variation in the number of territorial neighbours within the fragmented landscape in the conservation area, and on diel and seasonal variation in female and male song. We hypothesized that the number of conspecific neighbours would influence vocal behaviours, including female and male solo song rate, duet responsiveness rate, repertoire use, and song-switching rate. For females, we found that wrens change song-types more often in areas with more neighbours, whereas the other aspects of female vocal behaviour did not vary with the number of neighbours. For males, we found no aspect of vocal behaviour that varied with the number of neighbours. For both sexes, we found variation in vocal behaviours with time of day and time of year, in keeping with previous research. Our results underscore the idea that we must explore female and male birds independently, because the sexes may respond differently to external factors. We did not find strong links between wren vocal behaviour and variation in the number of neighbours, yet we encourage further behavioural studies on vocal behaviour of birds with varying numbers of neighbours in fragmented landscapes.

Intra‐seasonal rainfall variability and herbivory affect the interaction outcome of two dryland plant species

AbstractIncreases in drought frequency in combination with overgrazing may result in degradation of (semi‐) arid ecosystems. Facilitative interactions between plants are a key mechanism in preventing degradation, but it is poorly understood how they respond to increased stress by combined drought and herbivory. In this study, we used an ecohydrological model, to simulate the plant growth of two plant species interacting with each other under different rainfall and herbivory pressure scenarios. The functional traits of the two modeled plants were based on a prior field experiment in southeastern Spain, in which an unpalatable “nurse” species protected a palatable protégé species from herbivory. Moreover, the nurse species was more drought‐resistant; that is, it had a lower wilting point, whereas the protégé species had a higher optimal growth rate. Firstly, we investigated the coexistence of the two plant species growing under a single limiting resource, focusing on the effect of intra‐seasonal rainfall variability. We found that longer periods without rainfall within the wet season resulted in stable coexistence, whereas nearly constant rainfall led to competitive exclusion of the protégé by the nurse species. Secondly, we investigated how plant interactions varied along our studied gradients. Using the neighbor effect intensity and importance indices, we found that competitive effects increased with more constant rainfall. Moreover, higher herbivory rates resulted in increased facilitative effects of the nurse on the protégé species, but facilitative effects could only prevail over competitive effects under currently observed or higher intra‐seasonal rainfall variability. This study highlights the relevance of intra‐seasonal rainfall variability in explaining coexistence of species in dryland ecosystems and shows that increasing intra‐seasonal rainfall variability or herbivory pressure can result in more facilitative effects from a nurse species. This information is crucial to obtain a better insight into the long‐term coexistence of species, and the resulting stability of dryland ecosystems in response to future climate change.

Factors affecting survival of seedling of Afzelia africana, a threatened tropical timber species in West Africa

Understanding abiotic and biotic factors affecting the survival of seedlings of threatened species such as Afzelia africana is fundamental for restoration and sustainable management purposes. This study used seedling individual-level morphological data and plot-level data to assess the effect of abiotic (season, elevation, soil type and terrain slope) and biotic (seedling initial density, basal diameter, height and number of leaves, insect and fungal infection, insect herbivory, mammal herbivory, vegetation type, adult conspecific density and diameter, and heterospecific density and diameter) factors on the survival probability (at individual level) and survival rate (at plot level) of seedlings of A. africana in the Pendjari Biosphere Reserve. Generalized Linear Mixed Models (GLMMs) were used for data analyses. At individual level, we found that the survival probability of A. africana seedlings increased with initial height, but decreased from wet to dry season. At plot level, the survival rate of A. africana seedlings also decreased from the wet season (0.72 ± 0.05) to the dry season (0.18 ± 0.04) and was inversely proportional to seedling basal diameter (P = 0.024) and density of conspecific adults (P = 0.016). There were also positive effects of seedling initial height (P = 0.026) and mean diameter of conspecific adults (P = 0.037) on survival rate. Among abiotic factors, only terrain slope showed significant and negative effect (P = 0.028) on the survival rate, suggesting higher survival rate on flat terrain. Our findings suggest that sustainably managing seedlings of A. africana would require accounting for conspecific neighboring effect, terrain slope and season-specific actions. Practical aspects of these factors were further discussed.

Determine neighboring region spatial effect on dengue cases using ensemble ARIMA models

The state of Selangor, in Malaysia consist of urban and peri-urban centres with good transportation system, and suitable temperature levels with high precipitations and humidity which make the state ideal for high number of dengue cases, annually. This study investigates if districts within the Selangor state do influence each other in determining pattern of dengue cases. Study compares two different models; the Autoregressive Integrated Moving Average (ARIMA) and Ensemble ARIMA models, using the Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC) measurement to gauge their performance tools. ARIMA model is developed using the epidemiological data of dengue cases, whereas ensemble ARIMA incorporates the neighbouring regions’ dengue models as the exogenous variable (X), into traditional ARIMA model. Ensemble ARIMA models have better model fit compared to the basic ARIMA models by incorporating neighbuoring effects of seven districts which made of state of Selangor. The AIC and BIC values of ensemble ARIMA models to be smaller compared to traditional ARIMA counterpart models. Thus, study concludes that pattern of dengue cases for a district is subject to spatial effects of its neighbouring districts and number of dengue cases in the surrounding areas.

Early exit from business, performance and neighbours’ influence: a study of farmers in France

Abstract This article investigates the effects of economic performance and neighbours’ characteristics on farmers’ exit behaviour before retirement age. Using a unique set of social security data describing all French farmers under 50 over the years 2004–2017, we explore how these effects depend on farmers’ characteristics and how they stand relative to their neighbours. Our probit estimations reveal that younger farmers and farmers operating smaller farms are more sensitive to their own and neighbours’ performance than other farmers. Allowing for an asymmetric comparison effect between farmers and their neighbours, we uncover a nonlinear influence of own and neighbours’ profit and size.