University of Wisconsin–Milwaukee

About: University of Wisconsin–Milwaukee is a education organization based out in Milwaukee, Wisconsin, United States. It is known for research contribution in the topics: Population & Gravitational wave. The organization has 11839 authors who have published 28034 publications receiving 936438 citations. The organization is also known as: UWM & University of Wisconsin-Milwaukee.

Transformation of social networks in the late pre-Hispanic US Southwest

Abstract: The late pre-Hispanic period in the US Southwest (A.D. 1200–1450) was characterized by large-scale demographic changes, including long-distance migration and population aggregation. To reconstruct how these processes reshaped social networks, we compiled a comprehensive artifact database from major sites dating to this interval in the western Southwest. We combine social network analysis with geographic information systems approaches to reconstruct network dynamics over 250 y. We show how social networks were transformed across the region at previously undocumented spatial, temporal, and social scales. Using well-dated decorated ceramics, we track changes in network topology at 50-y intervals to show a dramatic shift in network density and settlement centrality from the northern to the southern Southwest after A.D. 1300. Both obsidian sourcing and ceramic data demonstrate that long-distance network relationships also shifted from north to south after migration. Surprisingly, social distance does not always correlate with spatial distance because of the presence of network relationships spanning long geographic distances. Our research shows how a large network in the southern Southwest grew and then collapsed, whereas networks became more fragmented in the northern Southwest but persisted. The study also illustrates how formal social network analysis may be applied to large-scale databases of material culture to illustrate multigenerational changes in network structure.

Engineering of SiO 2 Nanoparticles for Optimal Performance in Nano Cement-Based Materials

Abstract: The reported research examined the effect of 5-70 nm SiO2 nanoparticles on the mechanical properties of nano-cement materials The strength development of portland cement with nano-SiO2 and superplasticizing admixture was investigated Experimental results demonstrate an increase in the compressive and flexural strength of mortars with developed nanoparticles The distribution of nano-SiO2 particles within the cement paste plays an essential role and governs the overall performance of these products Therefore, the addition of a superplasticizer was proposed to facilitate the distribution of nano-SiO2 particles Superplasticized mortars with 025% of selected nano-SiO2 demonstrated a 16% increase of 1-day compressive strength, reaching 639 MPa; the 28-day strength of these mortars was 959 MPa (vs strength of reference superplasticized mortars of 921 MPa) Increase of 28-day flexural strength of superplasticized mortars with selected nano-SiO2 was 18%, reaching 271 MPa It is concluded that the effective dispersion of nanoparticles is essential to obtain composite materials with improved performance

Effect of environmental variation on the invasive success of a nonindigenous forest herb

Abstract: With the ever-burgeoning spread of nonindigenous plants, often facilitated by human activities, it is imperative to conduct case studies of particular invasive plants and the sites they invade in order to develop effective and efficient habitat management strategies. Alliaria petiolata is a native European biennial mustard that has become a serious invasive pest in many North American forests. In order to better characterize habitat vul- nerability to invasion by A. petiolata, we conducted an experiment to test the effects of environmental heterogeneity in the form of habitat, microenvironment, and small-scale litter disturbance on A. petiolata germination, survival, growth, and reproduction. Treatments consisted of two habitats (upland and lowland), two microenvironments (forest edge and forest interior), and three small-scale litter disturbance treatments (control, litter completely removed, and litter partially removed). Seeds were sown into plots in November, and plots were monitored for two years. Lowland plots had greater soil moisture and less litter per unit area than upland plots. In general, forest edge plots had greater understory cover and light availability and lower overstory cover than forest interior plots. Rosette survival, mature plant survival, plant biomass, height, and fruit and seed production were significantly greater for plants in the lowland compared with plants in the upland. Germination, rosette survival, mature plant survival, and reproduction were significantly greater in the forest edge plots when compared with interior plots. Litter disturbance had no significant effect on germination, growth, or reproduction. It is apparent that site colonization by A. petiolata was not dependent on the creation of patches of bare soil by disturbance, since plants were capable of invading sites with an intact litter layer. Alliaria petiolata growth and repro- duction was greatest in plots with adequate soil moisture and increased light availability. Therefore, mesic forests with a more open canopy structure and forest trails or edges may be the most vulnerable to invasion and the most difficult sites to manage. Drier upland forest interiors, which were more resistant to invasion, may be more responsive to man- agement techniques.