City Of Basel Research Articles

Plant-mycorrhiza association in urban forests: Effects of the degree of urbanisation and forest size on the performance of sycamore (Acer pseudoplatanus) saplings

Environmental change as result of urbanisation can influence soil microbial communities in green areas. In cities, forests are among the most frequent types of green areas and provide a wide variety of ecosystem services for the residents, such as air cleaning, nutrient cycling and area for recreational activities. Mycorrhizal fungi play an important role for the establishment of trees and therefore for the natural regeneration of forests. We examined the effect of urbanisation on the arbuscular mycorrhizal (AM) fungal symbiosis and performance of Acer pseudoplatanus saplings in a controlled field experiment in forests situated in the city of Basel and its suburbs in Switzerland. A total of 660 one-year-old A. pseudoplatanus saplings were planted in plots in 11 forests, which differed in degree of urbanisation in the surroundings and size. Saplings including their full root systems were harvested after 4, 6 and 13 months. AM fungal colonisation was 15–45 % lower on roots of saplings growing in forests located in areas with a high degree of urbanisation than that on sapling roots in forests in less urbanised areas. Furthermore, AM fungal colonisation of saplings decreased with decreasing forest size. Sapling survival was not influenced by urbanisation, but by forest size. In particular, sapling survival was reduced in small and medium-sized forests. Sapling survival also increased with increasing percentage of AM fungal colonisation after 13 months. These urbanisation- and forest-size induced changes became more pronounced with the time elapsed since the saplings were planted. Our findings demonstrate the negative impact of urbanisation on AM fungal symbiosis and the performance of A. pseudoplatanus saplings and indicate that urbanisation is a threat for the long-term maintenance of intact small urban forests.

Impact of World War 1 on placenta weight, birth weight and other anthropometric parameters of neonatal health

BackgroundWars do not only affect combatant countries, populations in neutral zones can be afflicted by circumjacent conflicts as well, posing a great health burden on mothers and newborns. As neonatal health remains an ongoing cause for concern, identifying determinants that impede fetal growth is crucial. Under this pretext, the study aimed to analyze the impact of World War 1 in the neutral city of Basel on neonatal health by assessing changes in anthropometric parameters. MethodsA retrospective analysis of yearly cross sections of term births in the maternity hospital of Basel from 1912 to 1923 was conducted (n = 3718). We tested adjusted anthropometry for time trends in comparison to a pre-war baseline, including birth weight, placenta weight, birth length, ponderal index and gestational age. Interrelations of placenta weights and birth weights were examined separately through birth weight to placenta weight (BW/PW) ratios and residuals of placenta weight to birth weight regressions. ResultsBirth weights, placenta weights and residuals were at their lowest in 1918/19, a trend not reflected in BW/PW ratios. Birth lengths remained low while ponderal indexes declined during the entire period of war, gestational age remained rather stable. Discussion1918/19 were the pinnacle years for the population of Basel, who were suffering from general detrimental economic conditions, a food supply crisis and an outbreak of the Spanish Flu. These adverse circumstances coincided with low birth and placenta weights, residuals depicting the correlation of birth weights to placental weights more closely than bw/pw ratios.

Negotiating independence. Switzerland in 1647–48: Johann Rudolf Wettstein, mayor of the state (canton) of Basel City and negotiator for the Swiss Confederation

Cet article relate l’histoire de la négociation entreprise par M. Rudolf Wettstein, maire de Bâle, qui a pu obtenir du Saint-Empire germanique, lors des négociations qui aboutiront au Traité de Westphalie au 17 ème siècle, l’indépendance de la Confédération suisse. L’auteur fait d’abord le récit du déroulement et de la conclusion des négociations ; elles ont impliqué des négociations internationales multi-acteurs en Westphalie et des négociations internes multi-acteurs au sein de la Confédération suisse. Les concepts majeurs en théorie de la négociation sont ensuite mobilisés pour tenter de donner un sens à l’approche de Wettstein dans cette négociation pour l’indépendance. L’article se termine par une proposition visant à renforcer la théorisation et fournit des suggestions de concepts pour mieux saisir les négociations multi-acteurs.

A vulnerabilidade como condição antropológica segundo o motivo “Escada da vida” em uma xilogravura do século 19

Este artigo se dedica ao aparecimento do tema da vulnerabilidade, a partir do século 18, em xilogravuras cuja narrativa visual se refere ao processo de envelhecimento das pessoas em analogia com o motivo da escada ou dos degraus da vida. A ausência da consideração da deficiência como um possível atravessamento do ciclo da vida disparou o problema investigativo: Como se dá o aparecimento do tema da vulnerabilidade em xilogravuras cuja narrativa visual se refere ao motivo da escada ou dos degraus da vida, acompanhada por uma narrativa religiosa? Apresenta os resultados de uma pesquisa documental exploratória, realizada nos acervos do Museu da Imagem na cidade de Epinal, França, do Museu das Culturas, na cidade de Basileia, Suíça e da Igreja Estadual de Estugarda, Alemanha, no mês de julho de 2017. Argumenta, como primeiro resultado, comparando as narrativas visuais educacionais e religiosas, que há uma modificação da narrativa visual do motivo da escada da vida e que seu aparecimento antecipa, na área da educação, mas não na área da teologia, a consideração do respeito à vulnerabilidade como condição antropológica. Como segundo resultado, mostra-se a importância da cultura visual como narrativa própria e fonte essencial para as ciências humanas, em especial, para educação e as ciências da religião, neste caso a ressignificação da vulnerabilidade humana no campo da educação inclusiva que exige um novo olhar para a condição humana.

Die behördliche „Sorge“ um das Kind. Psychiatrische Konzepte und fürsorgerische Maßnahmen in Basel-Stadt (1945–1972)

During the 20th century the child protection provisions of the Swiss Civil Code created the legal preconditions for guardianship authorities to place children with foster families, or in care homes, reformatories or psychiatric institutions if they were at serious “risk”. This article shows how the guardianship authority of the city of Basel increasingly addressed the health of the children in order to justify its outplacement decisions. Children and their behaviour came under medical-psychiatric observation, resulting in the pathologisation of the child. Although the legal preconditions were conducted for the protection of the child, in the course of the 20th century, they resulted in the sanctioning of maladaptive behaviour and societal deviance.

Diglossia and Local Identity: Swiss German in the Linguistic Landscape of Kleinbasel (Asian Perspectives)

The city of Basel is situated in the German-speaking part of Switzerland, in the geographic triangle of three countries: France, Germany and Switzerland. Everyday urban life is characterised by the presence of Standard German and Swiss German as well as diverse migrant languages. Swiss German is ‘an umbrella term for several Alemannic dialects’ (Stepkowska 2012, 202) which differ from Standard German in terms of phonetics, semantics, lexis, and grammar and has no standard written form. Swiss German is predominantly used in oral forms, and Standard German in written communication. Furthermore, an amalgamation of bilingualism and diglossia (Stepkowska 2012, 208) distinguishes the specific linguistic situation, which indicates amongst other things the high prestige of Swiss German in everyday life. To explore the visibility and vitality of Swiss German in the public display of written language, we examined the linguistic landscape of a superdiverse neighbourhood of Basel, and investigated language power and the story beyond the sign – ‘stories about the cultural, historical, political and social backgrounds of a certain space’ (Blommaert 2013, 41). Our exploration was guided by the question: How do linguistic artefacts – such as official, commercial, and private signs – represent the diglossic situation and the relation between language and identity in Kleinbasel? Based on a longitudinal ethnographic study, a corpus was compiled comprising 300 digital images of written artefacts in Kleinbasel. Participant observation and focus group discussions about particular images were conducted and analysed using grounded theory (Charmaz 2006) and visual ethnography (Pink 2006). In our paper, we focus on signs in Swiss German and focus group discussions on these images. Initial analyses have produced two surprising findings; firstly, the visibility and the perception of Swiss German as a marker of local identity; secondly, the specific context of their display.

Contested Architecture: The ‘Woba’ Residential Colony in Basel, 1930

In 1930, a housing exhibition called ‘Woba’ took place in the city of Basel. Unique for Switzerland, the commercial aspect of the furniture industry was complemented by a newly constructed residential colony. In accordance with discussions held one year before at the II CIAM congress in Frankfurt a. M., the Wohnung für das Existenzminimum was brought to life. Thirteen architectural offices experimented with different spatial designs in order to develop cheap and hygienic housing for the working class. For one month, some of the houses were open to the public. In the Swiss press, a vivid and controversial debate arose. On one side, its supporters advocated for standardized and rationalized housing as an appropriate way of living for modern individuals. On the other side, conservative forces saw a communist scheme at work in this housing in the style of Neues Bauen. By analyzing contemporary press articles on the Woba, this paper shows that the question of society’s future was being negotiated through architecture and furniture.

Experimental seismic performance of a half-scale stone masonry building aggregate

This paper focuses on the unidirectional dynamic shake-table test performed on a prototype of a natural stone masonry building aggregate. The half-scale prototype was designed to reproduce the features of existing unreinforced stone masonry building aggregates, typical of the historical centres in many European cities, including the city of Basel, Switzerland. The three-storey-high aggregate prototype consisted of two weakly connected structural units, with double-leaf undressed stone masonry walls incorporating a limited percentage of river pebbles. The specimen included flexible timber floor diaphragms and side-gabled timber roofs with different heights above the two units. Scaling the material mechanical properties of the specimen was necessary to satisfy similitude relationships without altering accelerations and material densities. An incremental, unidirectional dynamic test was performed up to near-collapse conditions of the prototype, using input ground motions selected to be compatible with realistic seismic scenarios for the region of Basel. This paper summarizes the main characteristics of the specimen and illustrates the evolution of its dynamic response and damage mechanisms.

Bikeability in Basel

“Bikeability” is becoming increasingly relevant in the field of transport- and urban planning. However, it is often unclear how bikeability is defined, let alone how it can be modeled. The goal of this project was to develop a quantitative method to model bikeability. A case study area in the city of Basel, Switzerland was selected for assessing the model. Here “bikeability” is understood as a measure of the ability and convenience in reaching important destinations by bike, based on the travel distance weighted by the perceived safety, -comfort, and -attractiveness of the streets and intersections along the routes. The underlying assumption was that cyclists try to minimize the distance traveled and maximize the perceived safety, -comfort, and -attractiveness of their route of choice. Unlike most of the previous bikeability assessments we reviewed, our method used existing route choice studies to identify attributes for quantifying cycling quality, which presumably results in a model that more accurately reflects real-life behavior. Many relevant attributes that have not been captured by previous models are included in this work, such as the high curbs of tram stops, tram tracks, and the turn direction at intersections. The method is suitable for several applications in urban planning, such as the identification of locations that need improvement and the comparison of planning measures. The current model covers conventional bikes used by commuting cyclists. However, the method could be used for E-bikes and non-commuting cyclists by applying the appropriate input values.

Functional perceptions, barriers, and demographics concerning e-cargo bike sharing in Switzerland

To reduce greenhouse gas emissions low-carbon transportation innovations are needed. One recent innovation is e-cargo bike sharing, which links established elements: a cargo bike, an electric motor, and sharing infrastructure. Existing research on mode sharing suggests that sharing schemes face difficulties to move beyond a specific group of early adopters. To gain insights into the characteristics of and perceived barriers for those who adopt e-cargo bike sharing and those who do not, we investigated four groups: active members, inactive members, potential members, and uninterested non-members. We analyzed survey data (n = 301) from members and non-members of an e-cargo bike sharing scheme in the city of Basel, Switzerland, to explore differences in current transportation patterns and sociodemographic characteristics among the four groups. Using a mixed-methods approach, we employed a multilevel regression model to analyze quantitative data. We also applied a qualitative coding system to investigate open-ended survey questions. We found that the present scheme is more likely to attract men, cyclists, and young people; however, other groups were interested. Factors that inhibit wider adoption include safety concerns and the configuration of the sharing procedure. More effort that considers the links among infrastructure, road safety, and cycling competences is required to support the adoption of e-cargo bike sharing as a low-carbon transportation innovation.

Air-conditioner cooling towers as complex reservoirs and continuous source of Legionella pneumophila infection evidenced by a genomic analysis study in 2017, Switzerland.

IntroductionWater supply and air-conditioner cooling towers (ACCT) are potential sources of Legionella pneumophila infection in people. During outbreaks, traditional typing methods cannot sufficiently segregate L. pneumophila strains to reliably trace back transmissions to these artificial water systems. Moreover, because multiple L. pneumophila strains may be present within these systems, methods to adequately distinguish strains are needed. Whole genome sequencing (WGS) and core genome multilocus sequence typing (cgMLST), with their higher resolution are helpful in this respect. In summer 2017, the health administration of the city of Basel detected an increase of L. pneumophila infections compared with previous months, signalling an outbreak.AimWe aimed to identify L. pneumophila strains populating suspected environmental sources of the outbreak, and to assess the relations between these strains and clinical outbreak strains.MethodsAn epidemiological and WGS-based microbiological investigation was performed, involving isolates from the local water supply and two ACCTs (n = 60), clinical outbreak and non-outbreak related isolates from 2017 (n = 8) and historic isolates from 2003–2016 (n = 26).ResultsIn both ACCTs, multiple strains were found. Phylogenetic analysis of the ACCT isolates showed a diversity of a few hundred allelic differences in cgMLST. Furthermore, two isolates from one ACCT showed no allelic differences to three clinical isolates from 2017. Five clinical isolates collected in the Basel area in the last decade were also identical in cgMLST to recent isolates from the two ACCTs.ConclusionCurrent outbreak-related and historic isolates were linked to ACCTs, which form a complex environmental habitat where strains are conserved over years.

The institutional challenges of scaling-up housing retrofit: the Swiss cities of Basel and Sion

Purpose This paper aims to discuss the nexus between two societal (sub) systems of housing and energy supply to shed new light on the key institutional barriers to socio-technical energy transition in the built environment. The key research question is to explore if and how key patterns of institutional elements associated with energy retrofit and energy supply are combined, co-evolved and played out in the housing system, leading to an alternative energy transition pathway in the built environment. Design/methodology/approach A comparative case study of residential buildings in the Swiss cities of Basel and Sion is conducted to map retrofitting policies and practices in a wide range of buildings (e.g. multi-family and single family) that each requires a particular constellation of institutions, actors and artefacts. Findings The key finding is that the regulative institutions support energy transition in each urban form/housing type. However, the co-evolution with normative and cultural-cognitive institutions does not play out very clearly in the housing system. One reason is that the norms and cultures are deeply rooted in the practices exercised by business community and households and therefore they need a longer time frame to adapt to a new regulation. Research limitations/implications The policies and actions to increase the rate of housing retrofit are discussed in the specific socio-political context of Switzerland. Therefore, the results of this study might not be applied in other contexts with different conditions, limiting the possibility for analytical generalization. The case study can generate only context-specific knowledge, which might be valuable only to cities with similar conditions. This paper addresses theoretical, methodological and policy challenges in scaling-up retrofit projects by taking a holistic and integrated approach to the systems of housing and energy supply. Practical implications It would have been necessary to find out how the introduction and enforcement of new energy policies and regulations (regulative institutions) have changed the norms and building practices (normative institutions) used by actors from housing industry and the attitudes and energy consumption behaviour of the households (cultural-cognitive institutions). Nevertheless, information about normative and cultural-cognitive institutions require more primary data in the form of interviews with organizations and households, respectively, which goes beyond the scope and resources of this study. Originality/value Insights from different strands of literature (institutions and sustainability transition) are combined to understand if and how retrofitting practices go along with other elements of urban sustainability including architectural, technical, socio-cultural and economic factors.

Prediction of Solar Radiation Intensity using Extreme Learning Machine

The generated energy capacity at a solar power plant depends on the availability of solar radiation. In some regions, solar radiation is not always available throughout the day, or even week, depending on the weather and climate in the area. To be able to produce energy optimally throughout the year, the availability of solar radiation needs to be predicted based on the weather and climate behavior data. Many methods have been so far used to predict the availability of solar radiation, either by mathematical approach, statistical probability, or even artificial intelligence-based methods. This paper describes a method of predicting the availability of solar radiation using the Extreme Learning Machine (ELM) method. It is based on the artificial intelligence methods and known to have a good prediction accuracy. To measure the performance of the ELM method, a conventional forecasting method using the Multiple Linear Regression (MLR) method has been used as a comparison. The implementation of both the ELM and MLR methods has been tested using the solar radiation data of the Basel City, Switzerland, which are available to public. Five years of data have been divided into training data and testing data for 6 case-studies considered. Root Mean Square Error (RMSE) and Mean Absolute Error (MAE) have been used as the parameters to measure the prediction results based on the actual data analysis. The results show that the obtained average values of RMSE and MAE by using the ELM method respectively are 122.45 W/m<sup>2</sup> and 84.04 W/m<sup>2</sup>, while using the MLR method they are 141.18 W/m<sup>2</sup> and 104.87 W/m<sup>2</sup> respectively. It means that the ELM method proved to perform better than the MLR method, giving 15.29% better value of RMSE parameter and 24.79% better value of MAE parameter.

Evaluating the effects of automated vehicle technology on the capacity of freeway weaving sections

Weaving sections, where a merge and a diverge are in close proximity, are considered as crucial bottlenecks in the highway network. Lane changes happen frequently in such sections, leading to a reduced capacity and the traffic phenomenon known as capacity drop. This paper studies how the emerging automated vehicle technology can improve the operations and increase the capacity of weaving sections. We propose an efficient yet effective multiclass hybrid model that considers two aspects of this technology in scenarios with various penetration rates: (i) the potential to control the desired lane change decisions of automated vehicles, which is represented in a macroscopic manner as the distribution of lane change positions, and (ii) the lower reaction time associated with automated vehicles that can reduce headways and the required gaps for lane changing maneuvers. The proposed model is successfully calibrated and validated with empirical observations from conventional vehicles at a weaving section near the city of Basel, Switzerland. It is able to replicate traffic dynamics in weaving sections including the capacity drop. This model is then applied in a simulation-based optimization framework that searches for the optimal distribution of the desired lane change positions to maximize the capacity of weaving sections. Simulation results show that by optimizing the distribution of the desired lane change positions, the capacity of the studied weaving section can increase up to 15%. The results also indicate that if the reaction time is considered as well, there is an additional combined effect that can further increase the capacity. Overall, the results show the great potential of the automated vehicle technology for increasing the capacity of weaving sections.

Modelling the vertical gradient of nitrogen dioxide in an urban area

IntroductionLand use regression models environmental predictors to estimate ground-floor air pollution concentration surfaces of a study area. While many cities are expanding vertically, such models typically ignore the vertical dimension. MethodsWe took integrated measurements of NO2 at up to three different floors on the facades of 25 buildings in the mid-sized European city of Basel, Switzerland. We quantified the decrease in NO2 concentration with increasing height at each facade over two 14-day periods in different seasons. Using predictors of traffic load, population density and street configuration, we built conventional land use regression (LUR) models which predicted ground floor concentrations. We further evaluated which predictors best explained the vertical decay rate. Ultimately, we combined ground floor and decay models to explain the measured concentrations at all heights. ResultsWe found a clear decrease in mean nitrogen dioxide concentrations between measurements at ground level and those at higher floors for both seasons. The median concentration decrease was 8.1% at 10 m above street level in winter and 10.4% in summer. The decrease with height was sharper at buildings where high concentrations were measured on the ground and in canyon-like street configurations. While the conventional ground floor model was able to explain ground floor concentrations with a model R2 of 0.84 (RMSE 4.1 μg/m3), it predicted measured concentrations at all heights with an R2 of 0.79 (RMSE 4.5 μg/m3), systematically overpredicting concentrations at higher floors. The LUR model considering vertical decay was able to predict ground floor and higher floor concentrations with a model R2 of 0.84 (RMSE 3.8 μg/m3) and without systematic bias. DiscussionHeight above the ground is a relevant determinant of outdoor residential exposure, even in medium-sized European cities without much high-rise. It is likely that conventional LUR models overestimate exposure for residences at higher floors near major roads. This overestimation can be minimized by considering decay with height.

Spatial Distribution of Sensible and Latent Heat Flux in the City of Basel (Switzerland)

Urban surfaces are a complex mixture of different land covers and surface materials; the relative magnitudes of the surface energy balance components therefore vary widely across a city. Eddy covariance (EC) measurements provide the best estimates of turbulent heat fluxes but are restricted to the source area. Land surface modeling with earth observation (EO) data is beneficial for extrapolation of a larger area since citywide information is possible. Turbulent sensible and latent heat fluxes are calculated by a combination of micrometeorological approaches (the aerodynamic resistance method, ARM), EO data, and GIS techniques. Input data such as land cover fractions and surface temperatures are derived from Landsat 8 OLI and TIRS, urban morphology was calculated from high-resolution digital building models and GIS data layers, and meteorological data were provided by flux tower measurements. Twenty-two Landsat scenes covering all seasons and different meteorological conditions were analyzed. Sensible heat fluxes were highest for industrial areas, railway stations, and areas with high building density, mainly corresponding to the pixels with highest surface-to-air temperature differences. The spatial distribution of latent heat flux is strongly related to the saturation deficit of vapor and the (minimum) stomatal resistance of vegetation types. Seasonal variations are highly dependent on meteorological conditions, i.e., air temperature, water vapor saturation deficit, and wind speed. Comparison of measured fluxes with modeled fluxes in the weighted source area of the flux towers is moderately accurate due to known drawbacks in the modeling approach and uncertainties inherent to EC measurements, particularly in urban areas.

Comparison of Solar Radiation Intensity Forecasting Using ANFIS and Multiple Linear Regression Methods

Solar radiation forecasting is important in solar energy power plants (SEPPs) development. The electrical energy generated from the sunlight depends on the weather and climate conditions in the area where the SEPPs are installed. The condition of solar irradiation will indirectly affect the electrical grid system into which the SEPPs are injected, i.e. the amount and direction of the power flow, voltage, frequency, and also the dynamic state of the system. Therefore, the prediction of solar radiation condition is very crucial to identify its impact into the system. There are many methods in determining the prediction of solar radiation, either by mathematical approach or by heuristic approach such as artificial intelligent method. This paper analyzes the comparison of two methods, Adaptive Neuro Fuzzy Inference (ANFIS) method, which belongs into the heuristic methods, and Multiple Linear Regression (MLP) method, which uses a mathematical approach. The performance of both methods is measured using the root mean square error (RMSE) and the mean absolute error (MAE) values. The data of the Swiss Basel city from Meteoblue are used to test the performance of the two methods being compared. The data are divided into four cases, being classified as the training data and the data used as predictions. The solar radiation prediction using the ANFIS method indicates the results which are closer to the real measurement results, being compared to the the use MLP method. The average values of RMSE and MAE achieved are 123.27 W/m2 and 90.91 W/m2 using the ANFIS method, being compared to 138.70 W/m2 and 101.56 W/m2 respectively using the MLP method. The ANFIS method gives better prediction performance of 12.51% for RMSE and 11.71% for MAE with respect to the use of the MLP method.

Deriving fragility functions from bilinearized capacity curves for earthquake scenario modelling using the conditional spectrum

The development of fragility curves to perform seismic scenario-based risk assessment requires a fully probabilistic procedure in order to account for uncertainties at each step of the computation. This is especially true when developing fragility curves conditional on an Intensity Measure that is directly available from a ground-motion prediction equation. In this study, we propose a new derivation method that uses realistic spectra instead of design spectral shapes or uniform hazard spectra and allows one to easily account for the features of the site-specific hazard that influences the fragility, without using non-linear dynamic analysis. The proposed method has been applied to typical school building types in the city of Basel (Switzerland) and the results have been compared to the standard practice in Europe. The results confirm that fragility curves are scenario dependent and are particularly sensitive to the magnitude of the earthquake scenario. The same background theory used for the derivation of the fragility curves has allowed an innovative method to be proposed for the conversion of fragility curves to a common IM (i.e. spectral acceleration or PGA). This conversion is the only way direct comparisons of fragility curves can be made and is useful when inter-period correlation cannot be used in scenario loss assessment. Moreover, such conversion is necessary to compare and verify newly developed curves against those from previous studies. Conversion to macroseismic intensity is also relevant for the comparison between mechanical-based and empirical fragility curves, in order to detect possible biases.

Investigation of temperature conditions in Swiss urban and suburban microhabitats for the overwintering suitability of diapausing Aedes albopictus eggs

BackgroundIn Switzerland, the invasive Asian tiger mosquito, Aedes albopictus, is firmly established in the Canton of Ticino, south of the Alps. According to a large-scale distribution model developed in 2013, suitable climatic conditions for the establishment of Ae. albopictus north of the Alps are found in Basel and Geneva while Zurich appears to be characterized by winters currently being too cold for survival of diapausing eggs. However, the spatial resolution of large-scale distribution models might not be sufficient to detect particular climatic conditions existing in urban settings, such as the presence of microclimatic temperatures, which may positively influence the probability of diapausing eggs to overwinter. In order to investigate this, microclimatic monitoring of potential diapausing sites (i.e. catch basins) and external controls was performed in January 2017 in Ticino and within the cities of Basel, Geneva and Zurich.ResultsMean January temperatures in catch basins of Basel, Geneva and Zurich were always higher than the -1 °C temperature threshold previously set for survival probability of diapausing eggs, while mean January temperatures were below -1 °C in several catch basins south of the Alps, where Ae. albopictus eggs currently overwinter. The catch basin absolute January daily minimum temperatures both south and north of the Alps were in general higher than the external control temperatures. Absolute January daily minimum temperatures in catch basins in Basel, Geneva and Zurich were always above -10 °C, indicating that diapausing Ae. albopictus eggs could potentially survive winter nights in urban areas north of the Alps.ConclusionsThe findings confirmed previous conclusions that urban catch basins can provide favourable conditions for overwintering of diapausing eggs compared to more cold-exposed sites. The results confirmed the presence of suitable winter conditions for the establishment of Ae. albopictus in the cities of Basel and Geneva. In addition, the microclimate-scale analysis added new information compared to the previous large-scale prevision model by showing that also the city of Zurich could provide winter conditions suitable for the establishment of Ae. albopictus. This illustrates the importance of the resolution of climate data in using models to predict Ae. albopictus distribution.

From Urban Agriculture to Urban Food

Urban agriculture is embedded in an urban food system, and its full potential can only be understood by looking into the dynamics of the system. Involving a variety of actors from civil society, policy, and the market, we conducted a comprehensive analysis of the food system of the city of Basel, Switzerland, including policy and actor analysis, analysis of perceptions on urban agriculture, food flow analysis, and a sustainability assessment. The article presents the results of these analyses and discusses how research can contribute to the societal debate on food systems transformation. We particularly reflect on how the research project became a boundary object in a dynamic process to develop new ideas and activities, as well as to create a space for future debates in the city’s food system.