Few studies have evaluated the joint effect of trace elements on spontaneous preterm birth (SPTB). This study aimed to examine the relationships between the individual or mixed maternal serum concentrations of Fe, Cu, Zn, Se, Sr and Mo during pregnancy, and risk of SPTB. Inductively coupled plasma MS was employed to determine maternal serum concentrations of the six trace elements in 192 cases with SPTB and 282 controls with full-term delivery. Multivariate logistic regression, weighted quantile sum regression (WQSR) and Bayesian kernel machine regression (BKMR) were used to evaluate the individual and joint effects of trace elements on SPTB. The median concentrations of Sr and Mo were significantly higher in controls than in SPTB group (P < 0·05). In multivariate logistic regression analysis, compared with the lowest quartile levels of individual trace elements, the third- and fourth-quartile Sr or Mo concentrations were significantly associated with reduced risk of SPTB with adjusted OR (aOR) of 0·432 (95 CI < 0·05). In multivariate logistic regression analysis, compared with the lowest quartile levels of individual trace elements, the third- and fourth-quartile Sr or Mo concentrations were significantly associated with reduced risk of SPTB with adjusted aOR of 0·432 (95 % CI 0·247, 0·756), 0·386 (95 % CI 0·213, 0·701), 0·512 (95 % CI 0·297, 0·883) and 0·559 (95 % CI 0·321, 0·972), respectively. WQSR revealed the inverse combined effect of the trace elements mixture on SPTB (aOR = 0·368, 95 % CI 0·228, 0·593). BKMR analysis confirmed the overall mixture of the trace elements was inversely associated with the risk of SPTB, and the independent effect of Sr and Mo was significant. Our findings suggest that the risk of SPTB decreased with concentrations of the six trace elements, with Sr and Mo being the major contributors.

This paper reconstructs and compares four squatter conflicts in Amsterdam, Nijmegen, Copenhagen and Hamburg during the 1980s in which squatters defended themselves from eviction from occupied houses by barricading entire streets. Remarkable similarities can be observed in how these conflicts developed. Was this the result of international contacts between the squatters, of similarities between the cities, or did the construction of barricades set in motion more general dynamics that influenced protest dynamics? This paper warns against overestimating the influence of transnational activist networks. Although the conflicts unfolded in similar ways while squatters fostered international contacts, the latter alone do not suffice to explain the former. Instead, this paper highlights the ‘social function’ of the barricade and the inherent conflict dynamics that barricade building set in motion.

We generalize the one-dimensional population model of Anguige & Schmeiser [1] reflecting the cell-to-cell adhesion and volume filling and classify the resulting equation into the six types. Among these types, we fix one that yields a class of advection-diffusion equations of forward-backward-forward type and prove the existence of infinitely many global-in-time weak solutions to the initial-Dirichlet boundary value problem when the maximum value of an initial population density exceeds a certain threshold. Such solutions are extracted from the method of convex integration by Müller & Šverák [12]; they exhibit fine-scale density mixtures over a finite time interval, then become smooth and identical, and decay exponentially and uniformly to zero as time approaches infinity. TE check: Please check the reference citation in abstract.

Canola, Brassica napus Linnaeus var. oleifera, is one of the main oilseeds grown in the world. Pollination is required to ensure an acceptable yield. Among the main bee pollinators (Hymenoptera: Apidae) occurring in canola in southern Brazil are Apis mellifera (Linnaeus) (Apidae: Apini) and Trigona spinipes (Fabricius) (Apidae: Meliponini). Plant genotype, sowing season, meteorological factors, and abundance of competitors can influence the foraging rate of A. mellifera and T. spinipes in canola, which will impact yield. We evaluated the effect of plant genotype, sowing season, and meteorological factors on the abundance of foraging bees, as well as their coabundance and impacts on canola yield. Under the conditions of the study, we did not observe significant variation between genotypes and sowing season on bee abundance and canola yield. We note that the impact of temperature and relative humidity are important predictors of abundance of A. mellifera and T. spinipes. The temperature and relative humidity effects, however, differed according to bee species. Coabundance patterns indicated no evidence of competitive exclusion. Higher canola yields were obtained when both bee species had high population abundance.