Can We Build Walkable Environments to Support Social Capital? Towards a Spatial Understanding of Social Capital; a Scoping Review

Empirical evidence suggests that it is possible to socially renew neighbourhoods through the formation of social capital (SC) as an effect of walking. The characteristics of the built environment that influence walkability and SC have been relatively well established by previous research, but contrasts remain. Therefore, this document seeks to investigate the relationship between SC and walkability, through a Scoping Review of empirical studies published in indexed journals in the Web of Science and Scopus. The findings indicate that the formation of SC as an effect of walking is associated with land use and the design of neighbourhood facilities; the provision of urban furniture (benches) and green spaces; and that the design and configuration of the neighbourhoods affects SC even more than the excess density. In addition, the methodological strategies used to arrive at these results were reviewed. The conclusions suggest the need to study this issue from an updated perspective, where new neighbourhood interaction systems can be tracked (that provide new indicators), using advanced tools and technologies that help streamline and make measurements more objective.

The structure of the surface layer of 0.4C-1Cr structural steel after finishing stages of machining by cutting

The microstructure and local fields of internal stresses arising in the surface layer of 0.4C-1Cr structural alloy steel (40X type) samples after machining by cutting are investigated. Before treatment, the samples were subjected to recrystallization annealing at a temperature of 600°C for 60 min. Sample processing was carried out in three modes: finishing (mode 1), sequential combination of roughing and semi-finishing (mode 2), sequential combination of roughing, semi-finishing and finishing (mode 3). With 1, 2 and 3 processing modes, chips are removed to a depth of 0.25, 1.5 and 1.75 mm, respectively. Transmission electron microscopy was used to determine the amplitude of the curvature-torsion of the crystal lattice of the forming phases, the excess density of dislocations, and the amplitude of internal stresses. It has been established that the main phase components in 40X steel after cutting are lamellar pearlite with different morphology and fragmented and unfragmented ferrite.

Effects of Phytoplankton Growth Phase on Settling Properties of Marine Aggregates

Marine snow aggregates often dominate carbon export from the surface layer to the deep ocean. Therefore, understanding the formation and properties of aggregates is essential to the study of the biological pump. Previous studies have observed a relationship between phytoplankton growth phase and the production of transparent exopolymer particles (TEP), the sticky particles secreted by phytoplankton that act as the glue during aggregate formation. In this experimental study, we aim to determine the effect of phytoplankton growth phase on properties related to aggregate settling. Cultures of the diatom Thalassiosira weissflogii were grown to four different growth phases and incubated in rotating cylindrical tanks to form aggregates. Aggregate excess density and delayed settling time through a sharp density gradient were quantified for the aggregates that were formed, and relative TEP concentration was measured for cultures before aggregate formation. Compared to the first growth phase, later phytoplankton growth phases were found to have higher relative TEP concentration and aggregates with lower excess densities and longer delayed settling times. These findings may suggest that, although particle concentrations are higher at later stages of phytoplankton blooms, aggregates may be less dense and sink slower, thus affecting carbon export.

The mirror mode: A superconducting space plasma analogue

We re-examine the physics of the magnetic mirror mode in its final state of saturation, the thermodynamic equilibrium, to demonstrate that the mirror mode is the analogue of a superconducting effect in a classical anisotropic-pressure space plasma. Two different spatial scales are identified which control the behaviour of its evolution. These are the ion inertial scale λim(τ) based on the excess density Nm(τ) generated in the mirror mode, and the Debye scale λD(τ). The Debye length plays the role of the correlation length in superconductivity. Their dependence on the temperature ratio τ = T‖ / T⊥ ν⊥th, is exceeded.