Mapping the Globalization of the Temporary Staffing Industry*

Very little is currently known about the globalization of the temporary staffing industry, a strategically significant sector given its role in promulgating wider labor market flexibility. This article starts to rectify this research lacuna in four ways: by conceptualizing the international expansion of temporary staffing and comparing it to other business service sectors, by identifying and mapping the top twenty transnational staffing agencies, by offering a typology of the leading transnational agencies based on their functional and geographic characteristics, and by charting a research agenda for future work on this sector.     

Fracturing and fluid‐flow during post‐rift subsidence in carbonates of the Jandaíra Formation,Potiguar Basin,NE Brazil

Pervasive fracture networks are common in many reservoir‐scale carbonate bodies even in the absence of large deformation and exert a major impact on their mechanical and flow behaviour. The Upper Cretaceous Jandaíra Formation is a few hundred meters thick succession of shallow water carbonates deposited during the early post‐rift stage of the Potiguar rift (NE Brazil). The Jandaíra Formation in the present onshore domain experienced <1.5 km thermal subsidence and, following Tertiary exhumation, forms outcrops over an area of >1000 km². The carbonates have a gentle, <5?, dip to the NE and are affected by few regional, low displacement faults or folds. Despite their simple tectonic history, carbonates display ubiquitous open fractures, sub‐vertical veins, and sub‐vertical as well as sub‐horizontal stylolites. Combining structural analysis, drone imaging, isotope studies and mathematical modelling, we reconstruct the fracturing history of the Jandaíra Formation during and following subsidence and analyse the impact fractures had on coeval fluid flow. We find that Jandaíra carbonates, fully cemented after early diagenesis, experienced negligible deformation during the first few hundreds of meters of subsidence but were pervasively fractured when they reached depths >400–500 m. Deformation was accommodated by a dense network of sub‐vertical mode I and hybrid fractures associated with sub‐vertical stylolites developed in a stress field characterised by a sub‐horizontal σ₁ and sub‐vertical σ₂. The development of a network of hybrid fractures, rarely reported in the literature, activated the circulation of waters charged in the mountainous region, flowing along the porous Açu sandstone underlying the Jandaíra carbonates and rising to the surface through the fractured carbonates. With persisting subsidence, carbonates reached depths of 800–900 m entering a depth interval characterised by a sub‐vertical σ₁. At this stage, sub‐horizontal stylolites developed liberating calcite which sealed the sub‐vertical open fractures transforming them in veins and preventing further flow. During Tertiary exhumation, several of the pre‐existing veins and stylolites opened and became longer, and new fractures were created typically with the same directions of the older features. The simplicity of our model suggests that most rocks in passive margin settings might have followed a similar evolution and thus display similar structures.     

Spatial Modeling of Geometallurgical Properties: Techniques and a Case Study

High-resolution spatial numerical models of metallurgical properties constrained by geological controls and more extensively by measured grade and geomechanical properties constitute an important part of geometallurgy. Geostatistical and other numerical techniques are adapted and developed to construct these high-resolution models accounting for all available data. Important issues that must be addressed include unequal sampling of the metallurgical properties versus grade assays, measurements at different scale, and complex nonlinear averaging of many metallurgical parameters. This paper establishes techniques to address each of these issues with the required implementation details and also demonstrates geometallurgical mineral deposit characterization for a copper–molybdenum deposit in South America. High-resolution models of grades and comminution indices are constructed, checked, and are rigorously validated. The workflow demonstrated in this case study is applicable to many other deposit types.     

Gender,Place, and Social Contacts: Understanding Awareness of Vulnerability to Terrorism

Abstract

Creating resiliency, accomplished in part by individuals preparing for disaster, is the primary strategy outside of law enforcement for responding to the threat of urban terrorism. Individuals prepare when they perceive a need to do so, yet little is known about what shapes a person's awareness of vulnerability to terrorism. Because evidence indicates that social contacts act as conduits of information and affect perception of risk to natural hazards, it is possible that such contacts also affect terrorism vulnerability awareness. Because social contacts are also known to be systematically segmented by gender and location, we hypothesized that conversations about terrorism vary by gender and place, specifically the home and work place. Drawing on data from 93 interviews with householders in Boston, the study demonstrates that: (1) family networks generated discussions of home preparedness, whereas workplace networks engaged a wider variety of topics; (2) women discussed terrorism more frequently and in greater depth than did men; and (3) women heard more preparedness messages for the home than did men, whereas men undertook preparedness activities external to the home. The findings bridge geography and terrorism studies by theorizing emplaced and subjective human experiences that prompt conversations about terrorism. These conversations, in turn, help urban emergency managers and risk-hazards geographers promote rational dialogue and action vis-à-vis terrorism. Hazards researchers have shown that the more people discuss terrorism, the less they seek extreme and unwarranted responses.     

Wavelet triangulated irregular networks

GIS applications have recently begun to emerge on the Internet. The management of three-dimensional geographic datasets in this distributed environment poses a particularly challenging problem, which highlights the need for a good data representation. This paper presents a new multiresolution data representation: the Wavelet Triangulated Irregular Network (WTIN). Compared to the traditional cell-based Digital Elevation Model (DEM) format and the Triangulated Irregular Network (TIN) format, it is more compact and suitable for scalable distributed GIS services. This format is based on the second-generation wavelet theory and is specially designed for geographical height field data. The modified Butterfly scheme is used for constructing the wavelet transform. For every point in the geographic surface, only a single wavelet coefficient is used, which makes the final data representation very efficient and easy to compress. Because the transform used in the data representation is a linear filter operation, the computational efficiency is better than other multiresolution data formats for terrain surfaces. Results from numerical experiments on real data are given to demonstrate that the proposed data representation can be efficiently implemented. The results show that the proposed WTIN data format can provide multiresolution data sets, which achieve significant compression while preserving geographical features. The quality is found to be quite acceptable for geographical terrain representation.     

Multiple Residence and Cyclical Migration: A Life Course Perspective*

As a result of restrictive time-space bounds in viewing migration, surprisingly little is known about the tempos and rhythms of geographical mobility in America. We discuss limitations of the conventional definition of migration and develop a life course framework of multiple residence and cyclical migration. Results of an Arizona-based case study reveal that multiple residence is common and more diverse than the annual influx of elderly snowbirds. Coming to grips with multiple residence and recurrent mobility in the United States represents a fundamental challenge in population and migration studies.     

Racism and Intolerance in Eastern Australia: a geographic perspective

Racism has become a fact of life in Australia over the past decade or so, yet there are relatively few studies of its nature or extent, and still fewer on its geography. Using a social constructivist approach, this study draws on a survey of 5056 respondents to investigate attitudes to racism and cultural diversity in New South Wales and Queensland, and of perceptions of out-groups as instances of ‘strangers in our midst’. On racism, results show the presence of a continuum of attitudes ranging from generally tolerant to generally intolerant, a presence which cuts across compositional (social or aspatial) characteristics to emphasise the existence of a distinctive geography, an everywhere different nature to racist and non-racist attitudes which transcends urban–rural and traditional social layers. On the other hand, perceptions of out-groups are not uniformly correlated with presence or absence of cultural diversity. In many cases, the ability to make judgements about significant ‘others’ or out-groups has been shown to relate more to abstract notions of self and national identity, reproduced in public by mainstream news media and political leaders. In particular, it may reflect an Anglo (or Anglo-Celtic) view on nationalism, which is a hallmark of the ‘new racism’: an assimilationist or ethnocultural view of Australian society which is different from the ‘civic nation’ ideal envisaged by multiculturalism. That the geography of attitudes and perceptions people have towards and about different cultural groups is so ‘everywhere different’ has important implications for attempts to address and redress issues of intolerance in Australia.     

Calculation of the effect of stratospheric mean wind variations on the solar semidiurnal barometric oscillation

Abstract

A simple perturbation procedure is developed for incorporating the effects of mean zonal winds in atmospheric tidal calculations. This method is used to determine the variation of the solar semidiurnal surface pressure oscillation, S₂(p), that is expected to result from the mean wind changes during the course of the quasi‐biennial oscillation of the tropical stratosphere. The results are consistent with earlier observations of a quasi‐biennial variation in S₂(p). Some new observations of biennial variability in S₂(p) at four tropical stations are also discussed.     

Equatorial Atlantic sea surface temperature variations: Research note

Abstract

Monthly mean sea surface temperature (SST) anomalies were computed for six 10°‐wide boxes stretching across the equatorial Atlantic Ocean for the period 1890–1979. These values were used to produce a time‐longitude section of the interannual SST variability along the equator. This section shows cycles of basin‐wide warming and cooling occurring with irregular periods that typically range between two and four years. The warming and cooling events in these cycles normally display some westward phase propagation. The peak magnitudes of the interannual SST anomalies are generally of the order of 1°C or less, except in the Gulf of Guinea where they can be somewhat larger.

An estimate was made of the basin‐wide equatorial SST anomaly in each month (excluding the Gulf of Guinea). This was composited around the times of the warm and cold extremes of the Pacific Southern Oscillation. This analysis revealed a detectable, but rather weak, tendency for phase locking of the interannual SST variations in the equatorial Pacific and Atlantic oceans.     

Evolution of a Carboniferous carbonate-hosted sphalerite breccia deposit,Isle of Man

A newly discovered, extensive sphalerite-bearing breccia (~7.5 wt.% Zn) is hosted in dolomitised Carboniferous limestones overlying Ordovician–Silurian metasedimentary rocks on the Isle of Man. Although base metal sulphide deposits have been mined historically on the island, they are nearly all quartz vein deposits in the metamorphic basement. This study investigates the origin of the unusual sphalerite breccia and its relationship to basement-hosted deposits, through a combination of petrographic, cathodoluminescence, fluid inclusion, stable isotope and hydrogeologic modelling techniques. Breccia mineralisation comprises four stages, marked by episodes of structural deformation and abrupt changes in fluid temperature and chemistry. In stage I, high-temperature (T _h > 300°C), high-salinity (20–45 wt.% equiv. NaCl) fluid of likely basement origin deposited a discontinuous quartz vein. This vein was subsequently dismembered during a major brecciation event. Stages II–IV are dominated by open-space filling sphalerite, quartz and dolomite, respectively. Fluid inclusions in these minerals record temperatures of ~105–180°C and salinities of ~15–20 wt.% equiv. NaCl. The δ³⁴S values of sphalerite (6.5–6.9‰ Vienna-Canyon Diablo troilite) are nearly identical to those of ore sulphides from mines in the Lower Palaeozoic metamorphic rocks. The δ¹⁸O values for quartz and dolomite indicate two main fluid sources in the breccia’s hydrothermal system, local Carboniferous-hosted brines (~0.5–6.0‰ Vienna standard mean ocean water) and basement-involved fluids (~5.5–11.5‰). Ore sulphide deposition in the breccia is compatible with the introduction and cooling of a hot, basement-derived fluid that interacted with local sedimentary brines.