Decoding Emergency Settlement through Quantitative Analysis

By the end of 2020, more than 80 million people were forcibly displaced around the world; this represents about one percent of the global population. Many of the displaced found shelter in emergency settlements; whether in refugee camps, IDP camps or community settlements. Some of these settlements are transitory, while others have been consolidated into permanent habitats; some span the size of a city, while others are the size of a village; some are well structured, while others provide only the bare minimum needed by residents. Notwithstanding these variations, there is still a lack of understanding of the range, depth, scale, and scope of these settlements. There is also a need for comparative analysis between different types of emergency settlements, as they are still generalized as temporary encampments. The aim of the study is to identify the distinctiveness of each type of emergency settlement to demonstrate that one strategy for their planning and management will not fit all. It does so by reviewing the criteria for analyzing emergency settlements around the world by using a quantitative analysis methodology on a set of variables considered relevant for the characterization of each typology based on a set of 500 cases. The results indicate that each type of emergency settlement has different characteristics and topology, and identify which variables, being identical, influence each typology differently. The article also discusses the basis for better-informed decision-making about the medium and long-term policies applicable to individual settlements.

Initial Assessments of a Handheld Indentation Probe's Correlation with Cancellous Bone Density, Stiffness and Strength: An Objective Alternative to 'Thumb Testing'

During shoulder arthroplasty, surgeons must select the optimal implant for each patient. The metaphyseal bone properties affect this decision; however, the typical resection 'thumb test' lacks objectivity. The purposes of this investigation were: to determine the correlation strength between the indentation depth of a handheld mechanism and the density, compressive strength and modulus of a bone surrogate; as well as to assess how changing the indenter tip shape and impact energy may affect the correlation strengths. A spring-loaded indenter was developed. Four tip shapes (needle, tapered, flat and radiused cylinders) and four spring energies (0.13J-0.76J) were assessed by indenting five cellular foam bone surrogates of varying density. The indentation depth was measured and correlated with apparent density, compressive strength and modulus. Indentation depth plateaued as the bone surrogate's material properties increased, particularly for indentation tips with larger footprints and the 0.13J spring. All tip shapes produced strong (R2≥0.7) power-law relationships between the indentation depth metric and the bone surrogate's material properties (density: 0.70 ≤ R2 ≤ 0.95, strength: 0.75 ≤ R2 ≤ 0.97, modulus: 0.70 ≤ R2 ≤ 0.93); though use of the needle tip yielded the widest indentation depth scale. These strong correlations suggest that a handheld indenter may provide objective intraoperative evidence of cancellous material properties. Further investigations are warranted to study indenter tip shape and spring energy in human tissue; though the needle tip with spring energy between 0.30J and 0.76J seems the most promising.

Supplemental Material: Regional chronostratigraphic synthesis of the Cenomanian-Turonian Oceanic Anoxic Event 2 (OAE2) interval, Western Interior Basin (USA): New Re-Os chemostratigraphy and 40Ar/39Ar geochronology

(1) Complete Ar geochronology data, bentonite correlations, and collection in Kaiparowits Plateau, Cenomanian-Turonian boundary age calculations, core photos and description of hiatuses, and Angus Core depth scale alignment correction. (2) Time scale tables for cores.

Are Cryosphere-Driven Feedbacks a Requisite for Abrupt Climate Events? (Site U610, DSDP Leg. 94)

<p>Abrupt climate events are important features of glacial climate scales on centennial and millennial timescales. These events' mechanistic trigger is often ascribed to either ice sheet-related feedback mechanisms or large freshwater pulses. In both cases, amplification occurs when these triggers bear upon the Atlantic Meridional Overturning Circulation (AMOC). However, the focus on glacial climate states in abrupt climate change research has led to an underrepresentation of research into interglacial periods. It thus remains unclear whether high-magnitude climate variability requires large cryosphere-driven feedbacks or whether it can also occur under low ice conditions. Using sediment core DSDP U610B (53°13.297N, 18°53.213W) located in the Rockall Trough, we present a high-resolution analysis of surface and deep water components of the AMOC spanning the transition from Marine Isotope Stage (MIS) 19.3 to 19.1 to test if orbital boundary conditions similar to our current Holocene can accommodate abrupt climate events. Above the core site, the dominant oceanographic feature is the North Atlantic Current and at 2417-m water depth, U610 is influenced by Wyville Thomson Overflow Water flowing southwards. We utilise a multiproxy approach including paired grain size analysis, planktic foraminifera assemblage counts, and ice-rafted debris counts within the same samples allowing us to resolve the timing between both surface and bottom components of the AMOC and their response to abrupt climate events during MIS-19 in the eastern subpolar gyre. We also present for the first time a new splice and composite depth scale for Site U610. Based on preliminary results, rapid shifts in both deep overflow and surface climate characterise this period.</p>

A diffusive description of Vertical Mixing in the Benthic Biolayer.

<p>In-stream environments, many biogeochemical processes occur in the benthic biolayer, i.e., within sediments at a very shallow depth close to the sediment-water interface (SWI). These processes are important for stream ecology and the overall environment.</p><p>Here, a 1D diffusive model is used to analyze the vertical exchange of solutes through the SWI and in the benthic biolayer. The model is applied to an extensive set of previously published laboratory experiments of solute exchange with different bed morphologies: flatbeds, dunes, and alternate bars. Although these different bed features induce mixing that is controlled by different physical processes at the SWI, overall mixing within the sediment is well represented by a parsimonious diffusive model, provided that the diffusivity profile declines exponentially with sediment depth.</p><p>For all morphology types, mixing is better simulated by an exponential diffusivity model than a constant diffusivity approach. Two parameters define the exponential diffusivity model; the effective diffusivity at the SWI, and a depth scale over which the exponential profile decays. Using a combination of classification and regression trees (CART) and multiple linear regression approaches, we demonstrate that a single predictive model captures measured variability in the effective diffusivity coefficient at the SWI across all morphological types. The best predictive model for the decay depth scale, on the other hand, is tailored to each morphological type separately.</p><p>The predictive framework developed here contributes to our understanding of the physical processes responsible for mixing across the SWI,  and therefore the in-bed processes that contribute to the biogeochemical processing of nutrients and other contaminants in streams.</p>

The evolution and arrest of a turbulent stratified oceanic bottom boundary layer over a slope: Upslope regime and PV dynamics

The influence of a sloping bottom and stratification on the evolution of an oceanic bottom boundary layer (BBL) in the presence of a mean flow is explored. As a complement to an earlier study (Ruan et al. 2019) examining Ekman arrest in a downslope regime, this paper describes turbulence and BBL dynamics during Ekman arrest in the upslope regime. In the upslope regime, an enhanced stratification develops in response to the upslope Ekman transport and suppresses turbulence. Using a suite of large-eddy simulations, we show that the BBL evolution can be described in a self-similar framework based on a non-dimensional number X/Xa. This non-dimensional number is defined as the ratio between the lateral displacement of density surfaces across the slope X and a displacement Xa required for Ekman arrest; the latter can be predicted from external parameters. Additionally, the evolution of the depth-integrated potential vorticity is considered in both upslope and downslope regimes. The PV destruction rate in the downslope regime is found to be twice the production rate in the upslope regime, using the same definition for the bottom mixed layer thickness. It is shown that this asymmetry is associated with the depth scale over which turbulent stresses are active. These results are a step towards improving parameterizations of BBL properties and evolution over sloping topography in coarse-resolution ocean models.

Supplemental Material: Regional chronostratigraphic synthesis of the Cenomanian-Turonian Oceanic Anoxic Event 2 (OAE2) interval, Western Interior Basin (USA): New Re-Os chemostratigraphy and 40Ar/39Ar geochronology

(1) Complete Ar geochronology data, bentonite correlations, and collection in Kaiparowits Plateau, Cenomanian-Turonian boundary age calculations, core photos and description of hiatuses, and Angus Core depth scale alignment correction. (2) Time scale tables for cores.

Supplemental Material: Regional chronostratigraphic synthesis of the Cenomanian-Turonian Oceanic Anoxic Event 2 (OAE2) interval, Western Interior Basin (USA): New Re-Os chemostratigraphy and 40Ar/39Ar geochronology

(1) Complete Ar geochronology data, bentonite correlations, and collection in Kaiparowits Plateau, Cenomanian-Turonian boundary age calculations, core photos and description of hiatuses, and Angus Core depth scale alignment correction. (2) Time scale tables for cores.