The ‘mosaic habitat’ concept in human evolution: past and present

The habitats preferred by hominins and other species are an important theme in palaeoanthropology, and the ‘mosaic habitat’ (also referred to as habitat heterogeneity) has been a central concept in this regard for the last four decades. Here we explore the development of this concept – loosely defined as a range of different habitat types, such as woodlands, riverine forest and savannah within a limited spatial area– in studies of human evolution in the last sixty years or so. We outline the key developments that took place before and around the time when the term ‘mosaic’ came to wider palaeoanthropological attention. To achieve this we used an analysis of the published literature, a study of illustrations of hominin evolution from 1925 onwards and an email survey of senior researchers in palaeoanthropology and related fields. We found that the term mosaic starts to be applied in palaeoanthropological thinking during the 1970’s due to the work of a number of researchers, including Karl Butzer and Glynn Isaac , with the earliest usage we have found of ‘mosaic’ in specific reference to hominin habitats being by Adriaan Kortlandt (1972). While we observe a steady increase in the numbers of publications reporting mosaic palaeohabitats, in keeping with the growing interest and specialisation in various methods of palaeoenvironmental reconstruction, we also note that there is a lack of critical studies that define this habitat, or examine the temporal and spatial scales associated with it. The general consensus within the field is that the concept now requires more detailed definition and study to evaluate its role in human evolution

The aging effect in Au-Cd alloys: A Mössbauer spectroscopy study

The martensite aging effect, observed in a number of alloy systems and through which fundamental properties for particular materials are altered by aging in the martensite state, has attracted considerable interest in recent years. It is important to understand and control the effect, particularly in shape-memory alloys for which stability of properties is fundamental to applications. The most likely model, at least for the Au-Cd system in which it bas been most critically tested, is the “symmetry conforming short-range order” (SC-SRO) model first proposed by Ren and Otsuka. $^{197}$Au Mössbauer spectroscopy offers the possibility to observe the nature of defects associated with the gold sites. The spectra for single crystal and polycrystalline Au-Cd in both the “aged martensite" and “quenched austenite” conditions are presented and discussed. While some uncertainty in interpretation of the spectra remains, particularly in relation to any quadruple splitting to be expected from either Au atoms on Cd-nearest-neighbour sites or the martensite lattice distortion, the best single-line fits provide evidence for two defect types

Least cost land-use changes for targeted catchment salt load and water yield impacts in south eastern Australia

This study reports an analysis of the economics of options for strategic land-use change to attain future catchment level target combinations of salt load and water yield. Farm level survey information on land use, productivity, prices and costs of production were integrated with spatially specific soil, rainfall, topography, hydrology and salinity results of the simulation model CAT (Catchment Analysis Tool). This information was used to populate a two stage economic optimization model in which subcatchment economic results were combined for catchment level analyses. This study is the first to exploit CAT results in an economic framework and the first in which economic results are mapped using CAT. The 64,000ha Bet Bet Catchment in Victoria, Australia, once deemed among the highest priority areas in the Murray Darling Basin for dryland salinity reduction, is the focus of this study. The calculated current net present value (NPV) of agricultural production in the catchment is AU$78 million3 while providing 42 GL of water yield4 annually for use downstream with a salt load of 22,600t. Results show that salt loads may be reduced to 18,600t (reduction of 4000t) through expansion of tree plantations and lucerne production, reducing water yield to 31 GL (11 GL reduction) and NPV to AU$ 63 million (AU$15 million reduction). Water yields could be increased from current levels by 2 GL while maintaining current salt loads. Alternatively, catchment NPV could be increased by approximately AU$ 7 million with little or no reduction in water yield; but there may be reasons (small farm size) why this is unlikely. For this catchment, the maximum reduction in salt load appears insufficient to justify public investment in tree planting and perennial pasture establishment, particularly when the reduced NPV and reduced water yields are taken into account. The results for this catchment do not support regulation of land use for the sake of lowering river salinity. However, the capacity of tree plantations to reduce water yields may support a regulation requiring purchase of water entitlements from downstream entitlement holders for new plantations. Despite millions of dollars of past public investment, it is now clear that Bet Bet Catchment was never one where land-use changes could benefit downstream water users. The approach described in this paper enables catchment management authorities to weigh costs of land-use change against downstream benefits and natural resource management (NRM) options elsewhere.Land-use Economic optimisation Salinity Environmental service Hydrology Simulation Farm survey Forest plantation

Upstream-downstream benefit analysis of policy on water use by upstream tree plantations

This study focuses on the problem of water use by new upstream commercial tree plantations where fully-committed water entitlements are already held and traded among downstream sectors (urban water, wetlands and agricultural industries). High tree product prices strongly incentivise expansion of upstream plantation areas, particularly if there is no accounting for the predictable extra interception and use of water by trees. Planters could benefit greatly at the expense of downstream water users. Plotting this in a public-private benefit framework (PPBF) suggests a policy of “flexible negative incentives” to limit expansion of new trees, rather than ‘across the board’ banning of new plantations. We explore the ‘flexible’ option and the current ‘no control’ option for a case-study area, the Macquarie River catchment in central- west NSW, Australia, using three scenario sets: (1) Policy setting — without or with the requirement for distributions of water use entitlements to be handled by extending the existing downstream market to new upstream plantations (the flexible negative incentive). (2) Expected tree-product values — four exogenous levels ($40,$50, $60 or$70/m3), provide positive incentives for establishing trees. (3) Water quality — FRESH or a hypothetical SALTY scenario where one of six up- stream watersheds seeps so much salt into the river that water for urban use is compromised when new plantations reduce fresh water yields from the other five. We estimate quantitative consequences of all 16 combinations of the above scenarios, and show how an extended water market can deliver “flexible incentives” for efficient water distributions in which all new upstream and old downstream users either benefit by trading or remain unaffected

Geomorphology and earth system science

Earth system science is an approach to obtain a scientific understanding of the entire Earth system on a global scale by describing how its component parts and their interactions have evolved, how they function, and how they may be expected to continue to evolve on all time-scales. The aim of this review is to introduce some key examples showing the role of earth surface processes, the traditional subject of geomorphology, within the interacting Earth system. The paper considers three examples of environmental systems in which geomorphology plays a key role: (i) links between topography, tectonics, and atmospheric circulation; (ii) links between geomorphic processes and biogeochemical cycles; and (iii) links between biological processes and the earth’s surface. Key research needs are discussed, including the requirement for better opportunities for interdisciplinary collaboration, clearer mathematical frameworks for earth system models, and more sophisticated interaction between natural and social scientists

Chronic Periodontitis Genome-wide Association Study in the Hispanic Community Health Study / Study of Latinos

Chronic periodontitis (CP) has a genetic component, particularly its severe forms. Evidence from genome-wide association studies (GWASs) has highlighted several potential novel loci. Here, the authors report the first GWAS of CP among a large community-based sample of Hispanics/Latinos. The authors interrogated a quantitative trait of CP (mean interproximal clinical attachment level determined by full-mouth periodontal examinations) among 10,935 adult participants (mean age: 45 y, range: 18 to 76 y) from the Hispanic Community Health Study / Study of Latinos. Genotyping was done with a custom Illumina Omni2.5M array, and imputation to approximately 20 million single-nucleotide polymorphisms was based on the 1000 Genomes Project phase 1 reference panel. Analyses were based on linear mixed models adjusting for sex, age, study design features, ancestry, and kinship and employed a conventional P < 5 × 10(−8) statistical significance threshold. The authors identified a genome-wide significant association signal in the 1q42.2 locus (TSNAX-DISC1 noncoding RNA, lead single-nucleotide polymorphism: rs149133391, minor allele [C] frequency = 0.01, P = 7.9 × 10(−9)) and 4 more loci with suggestive evidence of association (P < 5 × 10(−6)): 1q22 (rs13373934), 5p15.33 (rs186066047), 6p22.3 (rs10456847), and 11p15.1 (rs75715012). We tested these loci for replication in independent samples of European-American (n = 4,402) and African-American (n = 908) participants of the Atherosclerosis Risk in Communities study. There was no replication among the European Americans; however, the TSNAX-DISC1 locus replicated in the African-American sample (rs149133391, minor allele frequency = 0.02, P = 9.1 × 10(−3)), while the 1q22 locus was directionally concordant and nominally significant (rs13373934, P = 4.0 × 10(−2)). This discovery GWAS of interproximal clinical attachment level—a measure of lifetime periodontal tissue destruction—was conducted in a large, community-based sample of Hispanic/Latinos. It identified a genome-wide significant locus that was independently replicated in an African-American population. Identifying this genetic marker offers direction for interrogation in subsequent genomic and experimental studies of CP