Spatial diversity in invention: evidence from the early R&D labs

This article uses historical data on inventor and firm researchand development (R&D) lab locations to examine the technologicaland geographic structure of corporate knowledge capital accumulationduring a formative period in the organization of United Statesinnovation. Despite the localization of inventive activity aroundthe labs, one-quarter of inventors lived outside a 30 mile commutingradius of the nearest facility of the firm they assigned theirpatents to. A strong positive effect of distance from a labon technological importance is identified, especially for inventorsfrom large cities that were geographically separated from afirm's; labs. A patent case–control method helps explainspatial sourcing by showing that the average quality of externallyavailable inventions was high. Firms selected complementary,not substitute, inventions from non-lab urban locations, suggestinga link between the organization and the geography of innovation.     

Non-linear relationship between bulk δC and percent maize in carbonized cooking residues and the potential of false-negatives in detecting maize

Bulk δ¹³C values on charred cooking residues adhering to pottery sherd interior surfaces have been used as a source of information on the histories of maize in various locations in the western hemisphere. This approach is based on an assumption of a linear relationship between the percent maize in the resource mix cooked in a pot and δ¹³C. Previous experiments suggest that this relationship is non-linear, and maize may not be identified from bulk δ¹³C values even when it contributed substantially to the resource mix. A second round of experiments, presented here, indicates that the mobilization of carbon from maize and C₃ resources over time is the critical variable in residue formation and the resulting bulk δ¹³C value. This is influenced by the form of maize being cooked.     

Guanaco (Lama guanicoe) isotopic ecology in southern South America: spatial and temporal tendencies, and archaeological implications

We synthesize and discuss available isotopic data on Holocene guanaco samples from southern South America, extending from Tierra del Fuego Island to northern Patagonia and the Pampean region. We evaluate temporal and spatial tendencies on the basis of 91 samples (mainly based on δ¹³C_collagen values), presenting implications for paleodietary research in archaeology. We conclude that there are no strong correlations with latitude in the macro-spatial scale, while there is a set of interesting patterns at smaller regional scales. These patterns lead us to evaluate the role of ecologic and topographic variables (e.g. canopy effect, variations in altitude, ecotones) in structuring isotopic variability. Finally, on the basis of the present analysis we suggest a number of hypotheses and perspectives for the use of stable isotopes as geographic tracers of guanaco distribution in the past, and specific implications for the paleodietary study of human samples.     

Developing a documentation system for desert palaces in Jordan using 3D laser scanning and digital photogrammetry

Desert palaces in Jordan are unique pieces of art scattered in the desert as standing symbols of ancient civilizations. Due to their location, these palaces witness different environmental conditions which affect their status and sustainability. This raises the need to have a 3D documentation system reporting all spatial information for each palace, which can be used later for monitoring purposes. Digital photogrammetry is a generally accepted technique for the collection of 3D representations of the environment. For this reason, this image-based technique has been extensively used to produce high quality 3D models of heritage sites and historical buildings for documentation and presentation purposes. Additionally, terrestrial laser scanners are used, which directly measure 3D surface coordinates based on the run-time of reflected light pulses. These systems feature high data acquisition rates, good accuracy and high spatial data density. Despite the potential of each single approach, in our opinion, maximum benefit is to be expected by a combination of data from both digital cameras and terrestrial laser scanners. By these means the efficiency of data collection as well as the geometric accuracy and visual quality of the collected textured 3D models can be optimized. Within the paper, a 3D documentation system for Umayyad desert palaces in the Jordan desert will be presented using digital photogrammetry and laser scanning. The approach is demonstrated by generating high realistic 3D textured models for Amra and Kharanah palaces.     

Laser scanning for conservation and research of African cultural heritage sites: the case study of Wonderwerk Cave,South Africa

The ‘African Cultural Heritage and Landscape Database’ project, initiated and directed by the senior author and administered by Aluka (www.aluka.org), is aimed at the creation of a digital library of spatial and non-spatial materials relating to cultural heritage sites in Africa. The archaeological site of Wonderwerk Cave (South Africa) is one of the 19 sites documented to date using laser scanning, conventional survey, digital photogrammetry and 3D modelling. To date, it is one of the few archaeological caves worldwide to be fully scanned. This paper explores the different uses to which the spatial data derived from this cave have been, or will be, put – for historical and educational purposes, scientific research and site conservation and development.     

Comparing closed system, flow-through and fluid infiltration geochemical modelling: examples from K-alteration in the Ernest Henry Fe-oxide–Cu–Au system

Potassic alteration of rocks adjacent to, and within the Ernest Henry Fe‐oxide–Cu–Au deposit is used here as a test case to investigate fluid–rock interactions using various equilibrium dynamic geochemical modelling approaches available in the HCh code. Reaction of a simple K–Fe–(Na,Ca) brine (constrained by published fluid inclusion analysis) with an albite‐bearing felsic volcanic rock, resulted in predicted assemblages defined by (i) K‐feldspar–muscovite–magnetite, (ii) biotite–K‐feldspar–magnetite, (iii) biotite–quartz–albite and (iv) albite–biotite–actinolite–pyroxene with increasing rock buffering (decreasing log w/r). Models for isothermal–isobaric conditions (450°C and 2500 bars) were compared with models run over a T–P gradient (450 to 200°C and 2500 to 500 bars). Three principal equilibrium dynamic simulation methods have been used: (i) static closed system, where individual steps are independent of all others, (ii) flow‐through and flush, where a part of the result is passed as input further along the flow line, and (iii) fluid infiltration models that simulate fluid moving through a rock column. Each type is best suited to a specific geological fluid–rock scenario, with increasing complexity, computation requirements and approximation to different parts of the natural system. Static closed system models can be used to quickly ascertain the broad alteration assemblages related to changes in the water/rock ratio, while flow‐through models are better suited to simulating outflow of reacted fluid into fresh rock. The fluid infiltration model can be used to simulate spatially controlled fluid metasomatism of rock, and we show that, given assumptions of porosity relationships and spatial dimensions, this model is a first‐order approximation to full reactive transport, without requiring significant computational time. This work presents an overview of the current state of equilibrium dynamic modelling technology using the HCh code with a view to applying these techniques to predictive modelling in exploration for mineral deposits. Application to the Ernest Henry Fe‐oxide–Cu–Au deposit demonstrates that isothermal fluid–rock reaction can account for some of the alteration zonation around the deposit.     

Three-dimensional geometry, ore distribution and time-integrated mass transfer through the quartz–tourmaline–gold vein network of the Sigma deposit (Abitibi belt, Canada)

We present a reconstruction of the three‐dimensional (3D) geometry and gold grade distribution of shear zone‐hosted, Au‐mineralized, quartz–tourmaline veins of the Sigma deposit (Abitibi belt). Host shears and veins form a network of anastomosing, steeply dipping structures associated with smaller subhorizontal extensional veins. Our reconstruction has been carried out using the exceptionally large geological database of the mine. From this database, we extracted the geometric position, thickness and gold grades of geometrically best‐defined steep veins contained in a representative subvolume of the deposit. These data allowed the 3D representation of 53 veins, which have been constructed by fitting surfaces through the geometrical data and by contouring thickness and gold grade. The geometry of the network is mainly characterized by: (i) a few large segmented veins, with sinuous and helicoidal shape, and typical vertical dimension of >100 m; (ii) a large number of smaller vertical veins, some of which splay off the steep veins with high dip angles; (iii) subhorizontal extension veins (joints) located at, or close to, the tips of steep veins. The absolute thickness of the vertically short veins is the same as that of the large veins, suggesting that they formed simultaneously, but only a few of them interconnect to form vertically continuous bodies. Patchy, vertically elongated zones of high dilation are present in the large veins, and are poorly correlated with Au‐rich zones. They presumably represent former high‐permeability zones of the network. The highest gold grades occur at the interconnections between the large veins and small splays or subhorizontal joints. This indicates the important role of vein interconnection for fluid flow and gold precipitation within the network. Combining the calculation of the volume of the network with the estimation of tourmaline abundance in the veins, we calculate that 2.1 × 10⁶ m³ of tourmaline and 3.2 × 10⁶ m³ of quartz precipitated during Au deposition.     

Paleoethology as a tool for the development of archaeological models of land-use: the Crimean Middle Palaeolithic

The principal aim of our research is to capitalize on the close relationship between prehistoric hunters and prey to develop spatial models for the investigation of land-use patterns. Ideally, these models should be useful both as predictive tools for designing regional archaeological surveys, and as analytical tools for studying the distribution of known archaeological sites. Here, we build upon a basic G.I.S. model (including standard environmental variables such as slope, aspect and distance to water) adding a paleoethological variable in the form of range reconstructions for the regionally dominant, prehistoric human prey species: Equus hydruntinus.     

A 3D digital workflow for archaeological intra-site research using GIS

Across a range of archaeological projects in Northern Greece, a context-based system, which has much in common with similar stratigraphic methods applied elsewhere in the world, is in use to record the excavation process. Here, we discuss a formal data model and complete digital workflow for the documentation of this process in 3D using the prehistoric site of Paliambela Kolindros, Greece, as a case study. The entire digital process has the advantage of being implemented on a single software platform. In addition, the combination of formal ontology and custom object-oriented programming enables a suite of techniques for exploratory data analysis and stratigraphic interpretation.     

Integrated seismic tomography and ground-penetrating radar (GPR) for the high-resolution study of burial mounds (tumuli)

The study primarily aims at providing adequate imaging resolution of large and prominent targets of archaeological interest, such as pyramids and tumuli, at all depth levels. We implemented an integrated seismic tomography and georadar (STG) technique to perform high-resolution imaging and characterization of tumuli (burial mounds). We tested the proposed technique on a preserved late Bronze Age burial mound in northern Italy, for which STG succeeded in performing an accurate 3-D reconstruction of the structure and stratigraphy as proved by later archaeological excavations. We completed two transmission seismic tomography measurements, at present ground level and at 1.5 m elevation, with a 24-channel seismograph and 15° angular separation between geophones. The ground-penetrating radar (GPR) dataset encompasses 12 250 MHz radial profiles and 12 common mid point gathers for velocity analysis. Shallow layers of the mound are successfully imaged by GPR, whilst the structure of the deep central part of the tomb is reconstructed from seismic traveltime inversion. In particular, GPR images lenses and layers of sediments forming the external part of the tumulus, evidences of a looting attempt, peripheral structures associated with later exploitation of the mound (furnaces) and, in the external sector of the tumulus, the top of the deep layer of silty sediments covering the funeral chamber. Tomographic results reveal seismic velocity anomalies of potential archaeological interest at ground level, which were successively validated by archaeological excavations. The integration of GPR and tomographic datasets is an effective strategy to overcome the imaging and interpretation problems related to the structure of such peculiar funeral monuments. STG can be applied to a virtually unlimited dimensional range and requires a limited data acquisition, processing and inversion effort. The results of the study allowed the identification of the funeral chamber and a detailed imaging of layering and structural details.