City Of Hannover Research Articles

Assessing pollinator habitat suitability considering ecosystem condition in the Hannover Region, Germany

Abstract Context Habitat suitability for pollinator species is an important indicator for pollination ecosystem service potential, i.e. for biodiversity and crop provision. Modelling habitat suitability using an expert- and process-based models such as ESTIMAP-pollination is a common and accepted approach to spatially analyse pollination service potential and to make recommendations for planning. Objectives However, the suitability as a pollinator habitat depends not only on the land use type. It is also important to consider the condition of the habitat. For this reason, ecosystem condition information was used as a parameter for ESTIMAP modelling for the first time. Ecosystem condition data was used besides the commonly (in ESTIMAP) used information from expert assessments and from land use data. Methods As parameters for ecosystem condition, the management intensity in agro ecosystems, the management of forests and the proportion of green space in urban areas were included and affected the modelled habitat suitability for wild bees. Results Not all ecosystem types of the region were equally affected by the inclusion of the ecosystem condition parameter in the model. The most affected types were agricultural areas, such as arable and horticultural biotopes, whose suitability values decreased by 25.7%. As a result, areas with low suitability account for 41% of the region and 76.6% of the agro ecosystems. In forest, shrubs and woody plants land use types, the suitability decreased respectively by 4.3 and 6%. On the other hand, urban ecosystems in the city of Hannover were characterised by relatively good habitat suitabilities, especially in the proximity of wide urban forests. In 3.4% of the agricultural land, measures to support pollinators have been established. 1.6% of these measures are located in areas with low suitability. Conclusions The results show that ecosystem condition is, in addition to land use type, an important parameter to indicate habitat suitability for pollinators. Especially for ecosystem types with varying habitat suitabilities, such as agro ecosystems, the implementation of ecosystem condition parameters is recommendable. However, the selection of suitable ecosystem condition indicators still requires further research and concise definitions.

Contribution of rooftop rainwater harvesting to climate adaptation in the city of Hannover: Water quality and health issues of rainwater storage in cisterns and ponds

Rooftop rainwater harvesting systems and blue-green infrastructure are becoming important resilience alternatives for urban climate adaptation. This study sheds light on the largely unreported physicochemical and microbiological quality of private roof-harvested rainwater (RHRW). We aimed to identify the physicochemical and microbiological characteristics of RHRW, explore potential correlations between them and assess probable health risks associated with recreational interactions of children with the water. RHRW was collected from cisterns and ponds located in an inner courtyard in Hanover, Germany. Physicochemical parameters were measured on site and samples were collected once a month in two campaigns in 2020 and 2021. Escherichia coli concentrations ranged from 1 × 10° to 24.1 × 102 MPN/100 mL, Enterococci from 1 × 10° to 19.7 × 102 MPN/100 mL, Salmonella from 1 × 102 to 39 × 103 CFU/100 mL and Pseudomonas aeruginosa from 1 × 10° to 3 × 103 MPN/100 mL. Correlation analysis indicated potential relationships between bacteria, oxygen, and water temperature. The results of the health risk assessment indicated a potential risk of gastrointestinal illnesses due to exposure to Enterococci and Salmonella spp. present in the cisterns and ponds, highlighting the need for appropriate regulations and guidelines for RHRW aimed for non-potable uses. Blue-green infrastructure, when effectively managed and maintained, can offer benefits both by enhancing urban climate resilience and promoting citizens well-being.

The urban heat island under extreme heat conditions: a case study of Hannover, Germany

Global warming has resulted in higher frequencies of climate extremes, such as drought periods or heat waves. Heat waves are intensified in urban areas due to the urban heat island effect. Studies are inconclusive as to whether the urban heat island effect is intensified during heat waves. Using the city of Hannover, Germany, as a case study, we analysed the intensity of the urban heat island under unprecedented summer heat conditions in the years 2018, 2019 and 2020, which were among the hottest in Germany since weather records began. We compared the intensity of the urban heat island across these years with the non-heat year of 2017. Differences were analysed for various inner-city urban locations and an urban park, while accounting for their distinct land use and land cover characteristics. We identified the urban heat island effect across all years investigated in the study and also found a significant intensified urban heat island effect during the years of unprecedented heat, when night-time temperature minima are considered. The urban heat island was identified on a lower level, however, with maximum daily temperatures when compared to the non-heat year. The lowest intensity of the urban heat island was found for the urban park site, highlighting the need for more city-wide greening strategies, including tree-covered and open green spaces, to provide all residents with the cooling services of green spaces.

Microbiological water quality and derived health risks from exposure to ornamental water fountains in the city of Hannover.

Ornamental fountains are attractive urban infrastructures helping cities to cope with global warming, as water sprays have great cooling effects due to evaporative properties; however, exposure to microbiologically impaired water from ornamental fountains during recreational activities may result in adverse health outcomes for the exposed population. This study assesses the microbial water quality of four ornamental water fountains (Blätterbrunnen, Körtingbrunnen, Klaus-Bahlsen-Brunnen, and Marstallbrunnen) and performs a quantitative microbial risk assessment (QMRA) for children using Escherichia coli, Enterococci, and Salmonella to quantify the probability of gastrointestinal illnesses and Pseudomonas aeruginosa to quantify the risk of dermal infections. Samples were collected fortnightly in two campaigns in 2020 and 2021 and processed to determine bacterial concentrations. Data on exposure time were obtained during field observations on the selected fountains; a total of 499 people were observed of which 30% were children. Mean bacterial concentrations ranged from 1.6×101 to 6.1×102 most probable number (MPN)/100mL for E. coli, 1.2×101 -1.2×103 MPN/100mL for Enterococci, 8.6×103 -3.1×105 CFU/100mL for Salmonella, and 2.5×103 -3.2×104 MPN/100mL for P. aeruginosa. The results of the QMRA study showed that the USEPA illness rate of 36 NEEAR-gastrointestinal illnesses/1000 was exceeded for Enterococci at the Körtingbrunnen, Klaus-Bahlsen-Brunnen, and Marstallbrunnen fountains and for Salmonella and P. aeruginosa at the Körtingbrunnen fountain, suggesting that exposure to microbiologically contaminated water from ornamental fountains may pose a health risk to children. The scenario analysis shows the importance of keeping low bacterial concentrations in ornamental fountains so that the risk of illness/infection to children does not exceed the USEPA illness rate benchmark.

The epidemiology of dystonia: the Hannover epidemiology study

The prevalence of dystonia has been studied since the 1980s. Due to different methodologies and due to varying degrees of awareness, resulting figures have been extremely different. We wanted to determine the prevalence of dystonia according to its current definition, using quality-approved registries and based on its relevance for patients, their therapy and the health care system. We applied a service-based chart review design with the City of Hannover as reference area and a population of 525,731. Barrier-free comprehensive dystonia treatment in few highly specialised centres for the last 30 years should have generated maximal dystonia awareness, a minimum of unreported cases and a high degree of data homogeneity. Prevalence [n/1mio] and relative frequency is 601.1 (100%) for all forms of dystonia, 251.1 (42%) for cervical dystonia, 87.5 (15%) for blepharospasm, 55.2 (9%) for writer’s cramp, 38.0 (6%) for tardive dystonia, 32.3 (5%) for musician’s dystonia, 28.5 (5%) for psychogenic dystonia, 26.6 (4%) for generalised dystonia, 24.7 (4%) for spasmodic dysphonia, 20.9 (3%) for segmental dystonia, 15.2 (3%) for arm dystonia and 13.3 (2%) for oromandibular dystonia. Leg dystonia, hemidystonia and complex regional pain syndrome-associated dystonia are very rare. Compared to previous meta-analytical data, primary or isolated dystonia is 3.3 times more frequent in our study. When all forms of dystonia including psychogenic, generalised, tardive and other symptomatic dystonias are considered, our dystonia prevalence is 3.7 times higher than believed before. The real prevalence is likely to be even higher. Having based our study on treatment necessity, our data will allow better allocation of resources for comprehensive dystonia treatment.

ROAD TYPE CLASSIFICATION OF MLS POINT CLOUDS USING DEEP LEARNING

Abstract. Functional classification of the road is important to the construction of sustainable transport systems and proper design of facilities. Mobile laser scanning (MLS) point clouds provide accurate and dense 3D measurements of road scenes, while their massive data volume and lack of structure also bring difficulties in processing. 3D point cloud understanding through deep neural networks achieves breakthroughs since PointNet and arouses wide attention in recent years. In this paper, we study the automatic road type classification of MLS point clouds by employing a point-wise neural network, RandLA-Net, which is designed for consuming large-scale point clouds. An effective local feature aggregation (LFA) module in RandLA-Net preserves the local geometry in point clouds by formulating an enhanced geometric feature vector and learning different point weights in a local neighborhood. Based on this method, we also investigate possible feature combinations to calculate neighboring weights. We train on a colorized point cloud from the city of Hannover, Germany, and classify road points into 7 classes that reveal detailed functions, i.e., sidewalk, cycling path, rail track, parking area, motorway, green area, and island without traffic. Also, three feature combinations inside the LFA module are examined, including the geometric feature vector only, the geometric feature vector combined with additional features (e.g., color), and the geometric feature vector combined with local differences of additional features. We achieve the best overall accuracy (86.23%) and mean IoU (69.41%) by adopting the second and third combinations respectively, with additional features including Red, Green, Blue, and intensity. The evaluation results demonstrate the effectiveness of our method, but we also observe that different road types benefit the most from different feature settings.

Comparing different data sources by examining the associations between surrounding greenspace and children's weight status

BackgroundStudies on the association between surrounding greenspace and being overweight in childhood show inconsistent results, possibly because they differ widely in their definition and measurement of surrounding greenspace. Our aim was to evaluate whether the association of greenspace with being overweight depends on the measurement of greenspace in different data sources.MethodsBased on data from the school entry examinations of 22,678 children in the city of Hannover, Germany, from 2010 to 14, the association between greenspace availability and overweight was examined. Three different sources of greenspace availability were derived for a set of 51 areas of the city: The Normalized Difference Vegetation Index (NDVI), the OpenStreetMap (OSM) dataset, and the European Urban Atlas (UA) dataset. Agreement between the indicators on the quantity of greenspace coverage was compared. The association with children's BMI z-score, including potential interaction terms, was assessed using multilevel regression analysis.ResultsGreenspace availability per district area derived by NDVI was on average 42%, by OSM 29% and UA 22%, with OSM and UA being strongly correlated. Only the greenspace availability derived by NDVI showed an association with children's BMI z-score: The higher the greenspace availability was, the lower the BMI. The trend of association was higher for boys and migrant children than for girls and non-migrants and was restricted to the highest levels of greenspace availability.ConclusionsAssociations of greenspace with children's weight status depend on the greenspace measurement chosen. Surrounding greenspace was measured more comprehensively by NDVI. Data sources based on land use categories such as UA and OSM may be less suitable to reflect surrounding greenspace relevant for health outcomes. Potential mechanisms warrant further analysis and investigation.

Extensively managed or abandoned urban green spaces and their habitat potential for butterflies

Urban green spaces are often subject to intensive management and therefore only provide habitat for very few plant and animal species. Many studies have already proven that less intensive management of near-natural grassland habitats can increase species diversity, for example of butterflies. However, there is still a lack of knowledge as to what extent less intensive management of urban green spaces can promote urban butterfly diversity. Therefore, we examined parameters that determine the number of butterfly species in less maintained or even abandoned urban green spaces. We expected butterfly species richness and observation numbers to be affected by different management regimes. Butterfly surveys were carried out on 56 sites in the city of Hannover, Germany, in three consecutive years. The sites were subject to different management regimes. We explored parameters such as area size, the diversity of nectar plant species and habitat diversity for each site. A total of 34 species were recorded, with a minimum of 0 and a maximum of 17 species per site and year. The extreme drought and heat in 2018 clearly influenced the results of our study and this was reflected in massive decreases of observation numbers for some species. Less intensive management showed preferable effects in comparison to intensive management, but area size and nectar plants were more important factors influencing butterfly species richness and number of observations. Our results suggest that site parameters such as area size, nectar plant species richness or number of habitat types had stronger influences on butterflies than variations of extensive management. We conclude that less intensive urban green space management for good butterfly habitats is not a question of grazing, mowing or temporary abandonment, but instead must aim to increase nectar plant and habitat diversity.

Built Environment and Childhood Weight Status: A Multi-Level Study Using Population-Based Data in the City of Hannover, Germany.

In recent years, built environmental characteristics have been linked to childhood overweight, but the results remain inconsistent across studies. The present study examines associations between several built environmental features and body weight status (BMI) z-score among a large sample of preschool children in the city of Hannover, Germany. Walkability (Index), green space availability, and playground availability related to preschool children’s home environments were measured using data from OpenStreetMap (OSM). These built environment characteristics were linked to the data from the 2010–2014 school entry examinations in the Hannover city (n = 22,678), and analysed using multilevel linear regression models to examine associations between the built environment features and the BMI z-score of these children (4–8 years old). No significant associations of built environmental factors on children’s BMI were detected, but the effect between green space availability and BMI was modified by the parental educational level. In children with lower compared to higher educated parents, a higher spatial availability of greenspace was significantly associated with reduced body weight. Future research should continue to monitor the disparities in diverse built environment features and how these are related to children’s health.

Factors driving the vascular plant species richness in urban green spaces: Using a multivariable approach

Many studies have shown high vascular plant species richness in urban areas and, especially, in its green spaces. However, little is known about the factors driving the numbers and proportions of different species groups. The aim of our study was to test for the effects of patch size, patch shape, and distance to the urban edge as well as the combined effects of these factors on the numbers and proportions of total, native, non-native, endangered, ornamental, and nitrophilous vascular plant species. We conducted vascular plant surveys in 32 urban green spaces in the city of Hannover, Germany. We detected positive correlations between patch size and total, native, non-native, endangered, ornamental, and nitrophilous vascular plant species numbers and the proportion of endangered species by Spearman's rank correlations and linear regressions. A more compact patch shape, calculated by the shape index, affected the proportion of native, non-native, and ornamental species positively. Testing combined effects of factors with multiple linear regressions underlined the importance of patch size in combination with distance to the urban edge, and in combination with distance and patch shape. We conclude that in the context of recent urbanization processes, it is most important to create and conserve large urban green spaces (>6ha) in order to maintain vascular plant species richness. As species groups were affected most by different combinations of driving factors, our study highlights the importance of using multivariable approaches for detecting effects more precisely.

“Ein Laboratorium für eine veränderte Form von Kirche”

Abstract “A Laboratory for a Different Form of Church”: Interview by Felicia Brembeck with Torsten Pappert, Youth Church Hannover. Pappert, responsible for a Youth Church in the city of Hannover, describes his work, the roles of staff and volunteers, the target groups and the relationships to the parishes.

Home visits - central to primary care, tradition or an obligation? A qualitative study

BackgroundHome visits are claimed to be a central element of primary care. However, the frequency with which home visits are made is declining both internationally and in Germany despite the increase in the number of chronically ill elderly patients. Given this, the question arises as to how to ensure sufficient primary health care for this vulnerable patient group. The aim of this study was to explore German general practitioners' (GPs) attitudes with regard to the feasibility, burden and outlook of continued home visits in German primary care.MethodsQualitative semi-structured interviews were carried out with 24 GPs from the city of Hannover, Germany, and its rural surroundings. Data was analysed using qualitative content analysis.ResultsThe GPs indicated that they frequently conduct home visits, but not all of them were convinced of their benefit. Most were not really motivated to undertake home visits but some felt obliged to. The basic conditions covering home visits were described as unsatisfactory, in particular with respect to reimbursement and time constraints. House calls for vulnerable, elderly people remained undisputed, whereas visits of a social nature were mostly deleted. Urgent house calls were increasingly delegated to the emergency services. Visits to nursing homes were portrayed as being emotionally distressing. GPs considered good cooperation with nursing staff the key factor to ensure a successful nursing home visit. The GPs wanted to ease their work load while still ensuring quality home care but were unable to suggest how this might be achieved. Better financial compensation was proposed most often. The involvement of specially trained nurses was considered possible, but viewed with resentment.ConclusionsHome visits are still an integral aspect of primary care in Germany and impose a considerable workload on many practices. Though the existing situation was generally perceived as unsatisfactory, German GPs could not envisage alternatives if asked to consider whether the current arrangements were sustainable in the future. To guarantee an unaltered quality of primary home care, German GPs and health care policy makers should actively initiate a debate on the need for and nature of home visits in the future.

Variabilität von Arzturteilen in Schuleingangsuntersuchungen

Data from school entry examinations were used for studying the variability of judgements between physicians performing the examinations. Two diagnoses were subject to examination: 1) Obesity, because an external criterion was available for this one. The medical classifications were compared with automated classifications using an external criterion. 2) Language anomalies, because these are the most frequent diagnoses. No external criterion had been available, thus differences within the group of examining physicians were considered. Data from all school entry examinations performed in the city of Hannover between 1998 and 2001 were used. Altogether 14 physicians were involved, but due to low case numbers the data of two had to be omitted. The analyses are based on 18,303 datasets. For obesity the agreement rates between physicians' and automatically generated diagnoses were ascertained by calculating sensitivity and specificity. Comparisons of differences between physicians with respect to chances of getting a diagnosis were performed using logistic regression. The sensitivity of classifying body weights above the 75 (th) percentile correctly was 0.64 over all years of observation. The respective sensitivity of classifying children with body weights above the 97 (th) percentile was 0.70. Considerable differences over the four years of observation occurred. For performing logistic regressions, the diagnoses of the physician with the smallest difference from an external criterion were used as standard of comparison. The diagnoses of the physician with the largest difference yielded an OR=0.08. The overall variability within the group of examining physicians was large. With respect to language anomalies, although considerable, the within-group differences were smaller. The largest odds ratio in this case was OR=0.40. Diagnoses from school entry examinations vary according to the physicians involved. Thus the data should not be used for epidemiological studies. In order to improve data quality, the involved physicians should be extensively trained in using the instruments, and their instructions should be formulated more clearly in order to facilitate their application.

Spread of resistance to anticoagulant rodenticides in Germany

Resistance to anticoagulant rodenticides in Rattus norvegicus is now estimated to cover an area of roughly 26 000 km2 in northwest Germany. The chemical compounds involved are warfarin, coumatetralyl, bromadiolone and, to a lesser extent, difenacoum. Recent investigations revealed that the resistance area is extending considerably further east than was previously recorded. The easternmost populations containing resistant individuals are now present in the city of Hannover, whereas it seems that on the southern edge the urbanised Ruhr Basin remains mostly unaffected by resistance problems. Reported control failures with house mice (Mus musculus/domesticus) suggest that resistance to high potency compounds may occur, but these await scientific confirmation. We propose that molecular genetic testing methodology should be exploited to improve monitoring of anticoagulant resistance and provide more accurate information to users of rodenticides.

Sleep problems and daytime somnolence in a German population‐based sample of snoring school‐aged children

Habitual snoring is associated with daytime symptoms like tiredness and behavioral problems. Its association with sleep problems is unclear. We aimed to assess associations between habitual snoring and sleep problems in primary school children. The design was a population-based cross-sectional study with a nested cohort study. The setting was twenty-seven primary schools in the city of Hannover, Germany. Habitual snoring and sleep problems were assessed in primary school children using an extended version of Gozal's sleep-disordered breathing questionnaire (n = 1144). Approximately 1 year later, parents of children reported to snore habitually (n = 114) and an equal number of children who snored never or occasionally were given the Sleep Disturbance Scale for Children, a validated questionnaire for the assessment of pediatric sleep problems. Snoring status was re-assessed using the initial questionnaire and children were then classified as long-term habitual snorers or ex-habitual snorers. An increasing prevalence of sleep problems was found with increasing snoring frequency for sleep-onset delay, night awakenings, and nightmares. Long-term habitual snorers were at significantly increased risk for sleep-wake transition disorders (e.g. rhythmic movements, hypnic jerks, sleeptalking, bruxism; odds ratio, 95% confidence interval: 12.0, 3.8-37.3), sleep hyperhidrosis (3.6, 1.2-10.8), disorders of arousal/nightmares (e.g. sleepwalking, sleep terrors, nightmares; 4.6, 1.3-15.6), and excessive somnolence (i.e. difficulty waking up, morning tiredness, daytime somnolence; 6.3, 2.2-17.8). Ex-habitual snorers were at increased risk for sleep-wake transition disorders (4.4, 1.4-14.2). Habitual snoring was associated with several sleep problems in our study. Long-term habitual snorers were more likely to have sleep problems than children who had stopped snoring spontaneously.

Frequency distributions of the mixing height over an urban area from SODAR data

The height of the mixing-layer (MLH) is an important parameter in the assessment of the dilution of primarily emitted or secondarily formed air pollutants in the atmospheric boundary-layer. A continuous measurement of MLH is possible only by remote sensing. Here, 17 months of SODAR data have been analysed automatically to derive the MLH over the city of Hannover in Northern Germany. In contrast to earlier studies the MLH has been determined from vertical profiles of the acoustic backscatter intensity and from the variance of the vertical velocity component. The results are presented in form of monthly frequency distributions and mean daily courses of MLH. These statistical evaluations of MLH show a clear annual course and interannual variability. The study shows the possibility to derive meaningful climatological information from long-term SODAR measurements for air quality issues.

Flush cleaning of sewers

Flush cleaning experiments were conducted in a combined sewer in the city of Hannover using two existing gate valves. The aim of the investigation was to find a practicable cleaning recipe for a particular sewer section, where frequent cleaning actions are necessary due to massive sedimentation. Flush cleaning could be shown to be a powerful method to move sediments, however, the distance between the gate valves and the sewer section to be cleaned was to large, as to successfully clean the particular sewer section. The flush height, its velocity and duration, the frequency of flush events and perhaps the time of arrival of a flush are important qualities in oder to achieve good cleaning results. Modern flush cleaning tools like the Biogest system and the Hydrass Valve are powerful devices with excellent performances and without the shortcomings of other typs of valves. Flush cleaning should be considered when choosing a cleaning method for a particular sewer. It is a method which is economic and ecologic.

FLush cleaning of sewers

Flush cleaning experiments were conducted in a combined sewer in the city of Hannover using two existing gate valves. The aim of the investigation was to find a practicable cleaning recipe for a particular sewer section, where frequent cleaning actions are necessary due to massive sedimentation. Flush cleaning could be shown to be a powerful method to move sediments, however, the distance between the gate valves and the sewer section to be cleaned was to large, as to successfully clean the particular sewer section. The flush height, its velocity and duration, the frequency of flush events and perhaps the time of arrival of a flush are important qualities in oder to achieve good cleaning results. Modern flush cleaning tools like the Biogest system and the Hydrass Valve are powerful devices with excellent performances and without the shortcomings of other typs of valves. Flush cleaning should be considered when choosing a cleaning method for a particular sewer. It is a method which is economic and ecologic.

Modeling of multicomponent transport with microbial transformation in groundwater: The Fuhrberg Case

This paper serves the twofold purpose of demonstrating a numerical technique that appears to have potential in studies of nonlinear reactive transport problems and of presenting a case study where the implications of reactive transport processes are profound. The case study relates to the Fuhrberger Feld aquifer in northern Germany, which provides the bulk of the water supply for the half‐million city of Hannover. Part of the aquifer receives a strong influx of nitrate from agricultural activities. The nitrate in the aquifer is microbially transformed into sulfate, the transformation depending on the availability of reduced sulfur compounds present in the sediment, and the sulfate is also transformed further. The individual transformations occur within distinct reaction zones in the aquifer. The relevant dynamic processes can be formulated as a nonlinear transport problem involving multiple interacting species in dissolved or solid form. The system is simulated using a finite element‐based technique that generates a symmetric coefficient matrix for the transport equation, while providing second‐order accuracy in time. The form of the matrix allows the use of a highly efficient and robust symmetric conjugate gradient solver. The technique provides an ample spatial resolution capacity at reasonable cost and handles grids with irregular geometry in two or three dimensions. The convenience and versatility of conventional finite elements is retained. A vertical‐section simulation identifies different reaction zones in the aquifer and gives insight into the effect of the controlling parameters. The simulation study is a first step in the development of a prognosis for the fate of the groundwater resource.

Rückenschmerzen in Hannover

Between October 1984 and November 1987 a total of 5033 German residents of the City of Hannover, aged 25 to74, have been postally screened for rheumatic complaints during a population based study of the "prevalence and care of rheumatoid arthritis in the City of Hannover". 85% responded. The point prevalence of back pain "today" was 33%. There were significant differences in prevalence depending on sex and age. Higher prevalence rates were found for females and for persons of between 45 and 65 years of age.