Demographic Patterns of Reurbanisation and Housing in Metropolitan Regions in the US and Germany

After decades of decline, first signs of a central and inner city revitalisation were noticed towards the end of the 1980s in North American metropolitan areas. The repopulation and redevelopment of the metropolitan cores – often referred to as “reurbanisation”, “urban renaissance” or “back-to-the-city-movement” – has accelerated since then and is today one of the outstanding characteristics of recent urban development in the US. In Western and Central European urban regions, reurbanisation patterns were detected some years later although starting from a different level, as the inner cities have never faced a process of decay to the extent that was known in North American cities. At present, reurbanisation is intensely debated in urban and regional research. Although the evidence of reurbanisation is hardly questioned any longer, there is considerable uncertainty about how this new pattern of population change can be explained, how long it will last and how it will change the spatial urban structure of metropolitan areas in the long run. In this paper, we comparatively investigate recent trends of urban development in the US and Germany based on both survey and case study methods, with a focus on demographic patterns and housing. Our results suggest that reurbanisation is a universal trend in large metro regions in the Global North, manifesting itself as a significant repopulation and densification of core areas. At the same time, we found considerable divergence in terms of scale, dynamics and sociodemographic composition of reurbanisation patterns in the selected regions of the US and Germany. * This article belongs to a special issue on reurbanisation

Demographic Patterns of Reurbanisation and Housing in Metropolitan Regions in the US and Germany

"After decades of decline, first signs of a central and inner city revitalisation were noticed towards the end of the 1980s in North American metropolitan areas. The repopulation and redevelopment of the metropolitan cores - often referred to as 'reurbanisation', 'urban renaissance' or 'back-to-the-city-movement' - has accelerated since then and is today one of the outstanding characteristics of recent urban development in the US. In Western and Central European urban regions, reurbanisation patterns were detected some years later although starting from a different level, as the inner cities have never faced a process of decay to the extent that was known in North American cities. At present, reurbanisation is intensely debated in urban and regional research. Although the evidence of reurbanisation is hardly questioned any longer, there is considerable uncertainty about how this new pattern of population change can be explained, how long it will last and how it will change the spatial urban structure of metropolitan areas in the long run. In this paper, we comparatively investigate recent trends of urban development in the US and Germany based on both survey and case study methods, with a focus on demographic patterns and housing. Our results suggest that reurbanisation is a universal trend in large metro regions in the Global North, manifesting itself as a significant repopulation and densification of core areas. At the same time, we found considerable divergence in terms of scale, dynamics and sociodemographic composition of reurbanisation patterns in the selected regions of the US and Germany." (author's abstract

Stadtforschung

Stadtforschung ist ein Sammelbegriff für wissenschaftliche Fachdisziplinen, die sich theoretisch und empirisch mit der Stadt oder Teilen von ihr in sozio-ökonomischer, funktional- und sozialräumlicher sowie in historischer Perspektive befassen, vor allem Stadtsoziologie, Stadtgeographie und Stadtgeschichte. Das Verständnis von Stadt als Gegenstand der Forschung konstituiert sich über das jeweilige Fachverständnis und unterliegt im Laufe der Zeit Veränderungen

Reurbanisierung

Als Reurbanisierung wird eine Entwicklungsphase von Agglomerationsräumen westlicher Industriestaaten bezeichnet, in deren Verlauf die Kern- und Innenstädte durch den Zuwachs an Wohnbevölkerung und/oder Arbeitsplätzen wieder an sozialer, kultureller und ökonomischer Dynamik gewinnen. Erklärungen der Reurbanisierung verweisen auf ein komplexes Ineinandergreifen demografischer, ökonomischer, sozialer und politischer Faktoren

Barriers to using HIV pre-exposure prophylaxis (PrEP) and sexual behaviour after stopping PrEP: a cross-sectional study in Germany

Background Persistence of individuals at risk of HIV with Pre-Exposure Prophylaxis (PrEP) is critical for its impact on the HIV epidemic. We analysed factors associated with stopping PrEP, barriers that may deter people from continuing PrEP and investigated sexual behaviour after stopping PrEP. Methods Current and former PrEP users in Germany were recruited to complete an anonymous online survey on PrEP use and sexual behaviour. Participants were recruited through dating apps, a PrEP community website, anonymous testing sites and peers. The results were analysed using descriptive methods and logistic regression. Results We recruited 4848 current and 609 former PrEP users in two study waves (July–October 2018, April–June 2019). Former PrEP users were more likely 18–29 years old than current users (adjusted OR = 1.6, 95% confidence interval (CI) 1.1–2.3). Moreover, they were more often unhappy with their sex life, which was more pronounced in former daily PrEP users (aOR = 4.5, 95% CI 2.9–7.1) compared to former on-demand users (aOR = 1.8, 95% CI 1.1–2.9, pinteraction = 0.005). The most common reason for stopping PrEP was a reduced need for PrEP (49.1%). However, 31.4% of former users identified logistic reasons and 17.5% stopped due to side effects. Former PrEP users using PrEP < 3 months were more likely to stop PrEP due to concerns over long-term side effects (32.0% vs. 22.5%, p = 0.015) and not wanting to take a chemical substance (33.2% vs. 24.0%, p = 0.020) compared to former PrEP users who used PrEP for longer. After stopping PrEP, 18.7% of former PrEP users indicated inconsistent condom use while having ≥4 sex partners within the previous 6 months. Former PrEP users with many partners and inconsistent condom use more often indicated logistic reasons for stopping (46.5% vs. 27.9%, p < 0.001) than did other former PrEP users. Conclusions To maximise persistence with PrEP we need to develop strategies for younger PrEP users, reduce logistic barriers to access PrEP, and to develop effective communication on side-effect management. Moreover, prevention strategies for people stopping PrEP are required, since some remain at high risk for HIV.Peer Reviewe

HIV, STI and renal function testing frequency and STI history among current users of self-funded HIV pre-exposure prophylaxis, a cross-sectional study, Germany, 2018 and 2019

Introduction: Users of pre-exposure prophylaxis (PrEP) require periodic testing for HIV, sexually transmitted infections (STI) and renal function. Before PrEP was made free of charge through statutory health insurance in late 2019, PrEP users in Germany had to pay for testing themselves. Aim: We investigated self-reported HIV, STI and renal function testing frequencies among self-funded PrEP users in Germany, factors associated with infrequent testing, and STI diagnoses. Methods: A cross-sectional anonymous online survey in 2018 and 2019 recruited current PrEP users via dating apps for men who have sex with men (MSM), a PrEP community website, anonymous testing sites and friends. We used descriptive methods and logistic regression for analysis. Results: We recruited 4,848 current PrEP users. Median age was 37 years (interquartile range (IQR): 30–45), 88.7% identified as male, and respectively 26.3%, 20.9% and 29.2% were tested less frequently for HIV, STI and renal function than recommended. Participants with lower STI testing frequency were significantly less likely to report STI diagnoses during PrEP use, especially among those with many partners and inconsistent condom use. Factors most strongly associated with infrequent testing included not getting tested before starting PrEP, using PrEP from informal sources and on-demand/intermittent PrEP use. Discussion: In a setting of self-funded PrEP, many users obtained medical tests less frequently than recommended, which can lead to missed diagnoses. Barriers to testing should be addressed to enable proper medical supervision. The suitability of testing frequencies to PrEP users with less frequent risk exposures needs to be evaluated.Peer Reviewe

Feasibility of Digital Memory Assessments in an Unsupervised and Remote Study Setting

Sensitive and frequent digital remote memory assessments via mobile devices hold the promise to facilitate the detection of cognitive impairment and decline. However, in order to be successful at scale, cognitive tests need to be applicable in unsupervised settings and confounding factors need to be understood. This study explored the feasibility of completely unsupervised digital cognitive assessments using three novel memory tasks in a Citizen Science project across Germany. To that end, the study aimed to identify factors associated with stronger participant retention, to examine test-retest reliability and the extent of practice effects, as well as to investigate the influence of uncontrolled settings such as time of day, delay between sessions or screen size on memory performance. A total of 1,407 adults (aged 18-89) participated in the study for up to 12 weeks, completing weekly memory tasks in addition to short questionnaires regarding sleep duration, subjective cognitive complaints as well as cold symptoms. Participation across memory tasks was pseudorandomized such that individuals were assigned to one of three memory paradigms resulting in three otherwise identical sub-studies. One hundred thirty-eight participants contributed to two of the three paradigms. Critically, for each memory task 12 independent parallel test sets were used to minimize effects of repeated testing. First, we observed a mean participant retention time of 44 days, or 4 active test sessions, and 77.5% compliance to the study protocol in an unsupervised setting with no contact between participants and study personnel, payment or feedback. We identified subject-level factors that contributed to higher retention times. Second, we found minor practice effects associated with repeated cognitive testing, and reveal evidence for acceptable-to-good retest reliability of mobile testing. Third, we show that memory performance assessed through repeated digital assessments was strongly associated with age in all paradigms, and individuals with subjectively reported cognitive decline presented lower mnemonic discrimination accuracy compared to non-complaining participants. Finally, we identified design-related factors that need to be incorporated in future studies such as the time delay between test sessions. Our results demonstrate the feasibility of fully unsupervised digital remote memory assessments and identify critical factors to account for in future studies

Incremental value of biomarker combinations to predict progression of mild cognitive impairment to Alzheimer’s dementia

Background The progression of mild cognitive impairment (MCI) to Alzheimer’s disease (AD) dementia can be predicted by cognitive, neuroimaging, and cerebrospinal fluid (CSF) markers. Since most biomarkers reveal complementary information, a combination of biomarkers may increase the predictive power. We investigated which combination of the Mini-Mental State Examination (MMSE), Clinical Dementia Rating (CDR)-sum-of-boxes, the word list delayed free recall from the Consortium to Establish a Registry of Dementia (CERAD) test battery, hippocampal volume (HCV), amyloid-beta1–42 (Aβ42), amyloid-beta1–40 (Aβ40) levels, the ratio of Aβ42/Aβ40, phosphorylated tau, and total tau (t-Tau) levels in the CSF best predicted a short-term conversion from MCI to AD dementia. Methods We used 115 complete datasets from MCI patients of the “Dementia Competence Network”, a German multicenter cohort study with annual follow-up up to 3 years. MCI was broadly defined to include amnestic and nonamnestic syndromes. Variables known to predict progression in MCI patients were selected a priori. Nine individual predictors were compared by receiver operating characteristic (ROC) curve analysis. ROC curves of the five best two-, three-, and four-parameter combinations were analyzed for significant superiority by a bootstrapping wrapper around a support vector machine with linear kernel. The incremental value of combinations was tested for statistical significance by comparing the specificities of the different classifiers at a given sensitivity of 85%. Results Out of 115 subjects, 28 (24.3%) with MCI progressed to AD dementia within a mean follow-up period of 25.5 months. At baseline, MCI-AD patients were no different from stable MCI in age and gender distribution, but had lower educational attainment. All single biomarkers were significantly different between the two groups at baseline. ROC curves of the individual predictors gave areas under the curve (AUC) between 0.66 and 0.77, and all single predictors were statistically superior to Aβ40. The AUC of the two-parameter combinations ranged from 0.77 to 0.81. The three-parameter combinations ranged from AUC 0.80–0.83, and the four- parameter combination from AUC 0.81–0.82. None of the predictor combinations was significantly superior to the two best single predictors (HCV and t-Tau). When maximizing the AUC differences by fixing sensitivity at 85%, the two- to four-parameter combinations were superior to HCV alone. Conclusion A combination of two biomarkers of neurodegeneration (e.g., HCV and t-Tau) is not superior over the single parameters in identifying patients with MCI who are most likely to progress to AD dementia, although there is a gradual increase in the statistical measures across increasing biomarker combinations. This may have implications for clinical diagnosis and for selecting subjects for participation in clinical trials

Real-time evolution for weak interaction quenches in quantum systems

Motivated by recent experiments in ultracold atomic gases that explore the nonequilibrium dynamics of interacting quantum many-body systems, we investigate the nonequilibrium properties of a Fermi liquid. We apply an interaction quench within the Fermi liquid phase of the Hubbard model by switching on a weak interaction suddenly; then we follow the real-time dynamics of the momentum distribution by a systematic expansion in the interaction strength based on the flow equation method. In this paper we derive our main results, namely the applicability of a quasiparticle description, the observation of a new type of quasi-stationary nonequilibrium Fermi liquid like state and a delayed thermalization of the momentum distribution. We explain the physical origin of the delayed relaxation as a consequence of phase space constraints in fermionic many-body systems. This brings about a close relation to similar behavior of one-particle systems which we illustrate by a discussion of the squeezed oscillator; we generalize to an extended class of systems with discrete energy spectra and point out the generic character of the nonequilibrium Fermi liquid results for weak interaction quenches. Both for discrete and continuous systems we observe that particular nonequilibrium expectation values are twice as large as their corresponding analogues in equilibrium. For a Fermi liquid, this shows up as an increased correlation-induced reduction of the quasiparticle residue in nonequilibrium.Comment: 54 page