The Curiosity rover on the Mars Science Laboratory mission has found extensive evidence that Gale crater once hosted a habitable lacustrine environment; however, there are remaining questions about ...the chemistry and duration of the lake and the nature of the climate at the time. In this study, we use Mastcam multispectral data to investigate the mineralogy of the Sutton Island member of the Murray formation, a part of the basal layers of Mt. Sharp, which consists of heterolithic mudstone and sandstone that are distinct from the finely laminated mudstones that dominate much of the Murray. Sutton Island includes at least one instance of desiccation cracks, indicative of subaerial exposure, and uniquely irregular diagenetic features that may be related to local bedrock permeability. These features suggest that Sutton Island experienced a complex history of deposition and diagenesis which may be crucial for understanding changing water‐rock interactions within Gale. We find that most Mastcam bedrock spectra in this region lack the absorptions associated with hematite found throughout the Murray, and instead show deeper absorptions shifted toward longer wavelengths that are more consistent with Fe‐smectites such as nontronite. Elemental chemistry from ChemCam supports this interpretation, as SiO, MgO, Li, and the chemical index of alteration are elevated in this region. Combined with observations of bedrock sedimentology, this suggests that Sutton Island was deposited in a nearshore or low stand environment, and we hypothesize that the clay minerals were produced in this region due to sub‐aerial exposure and weathering in a semi‐arid climate.
Plain Language Summary
The Curiosity rover on the Mars Science Laboratory mission has found extensive evidence that Gale crater once hosted a habitable lake environment; however, there are remaining questions about the chemistry and timing of the lake and the nature of the climate at the time. In this study, we use Mastcam data to investigate the composition of the Sutton Island member of the Murray formation, which consists of mixed fine and coarse grained rocks that are distinct from the very fine‐grained rocks that dominate much of the Murray. Sutton Island includes mudcracks, indicative of surface exposure, and irregular alteration features that may be related to local bedrock differences. These features suggest that Sutton Island experienced a complex history of deposition and alteration which may be crucial for understanding changing water‐rock interactions within Gale. We find that most bedrock in this region lack features associated with hematite found throughout the Murray, and instead show features that are more consistent with clay minerals. Combined with observations of mudcracks and chemistry data, this suggests that Sutton Island was deposited in a nearshore environment, and we hypothesize that the clays were produced in this region due to surface exposure and weathering in a semi‐arid climate.
Key Points
Mastcam multispectral data in Sutton Island exhibit bands >900 nm consistent with Fe/Mg‐clay minerals like nontronite
Sutton Island was deposited in a lowstand/nearshore environment and exposed to more subaerial weathering than the nearby Murray
The presence of abundant clay minerals in Sutton Island significantly reduced fluid flow and alteration during later diagenesis
Purpose
The importance of networks in the internationalisation of entrepreneurial firms is widely accepted. However, while the literature tends to focus on the existing networks of firms, there is ...growing evidence that many rapid internationalisers have to build new networks. This cross‐national study investigates the networks of internationalising entrepreneurial firms in Australia, Canada, Ireland and New Zealand.
Design/methodology/approach
A multi‐stage approach and mixed methods were employed. Online sources were used to gather information on 218 internationalising small firms, then an e‐mail instrument was administered to verify data and address information gaps, resulting in 143 usable responses (66 per cent) evenly distributed across locations. A representative sub‐sample of 53 firms was selected for further in‐depth investigation via face‐to‐face interviews with CEOs.
Findings
A high proportion of firms (25 per cent) actively used existing networks to develop their knowledge of international markets and improve their international competitiveness. However, an even larger number (34 per cent) had to build new networks because of the advanced nature of their offering. In‐depth interviews provided rich insights into the nature and scope of the firms' network development activities.
Research limitations/implications
While the sample size is relatively small, the findings are consistent across locations. They suggest that further investigation of network building activities among internationalising entrepreneurial firms is required.
Practical implications
The results have implications on firm strategy, in terms of the strategic nature of network building and the need for systematic approaches. They also are pertinent to public policy in support of internationalisation. In particular, there is a need for support agencies to shift their focus from providing objective knowledge to supporting experiential learning and network development.
Originality/value
The linkage of extant network approaches to the emerging knowledge‐based view (KBV) of internationalisation enhances and advances both perspectives.
With increasing age and in patients affected with dry-eye symptoms, the human tear film becomes more unstable and exhibits shorter tear break-up times. We examined whether the inclusion of proteins ...and lipids to water affected the evaporation rates measured in vitro and could account for the lower rates reported previously from in vivo measurements. The impact of temperature, air flow, and humidity on the evaporation rate of tears was measured in vitro.
Lipid-protein interactions were measured using fluorescence spectroscopy and in vitro rates of evaporation were performed gravimetrically.
Human reflex tears evaporated at a rate similar to that of water. A temperature increase from 25 degrees C to 34 degrees C caused a threefold increase in the evaporation rates of tears in still air. Further increases were observed under a current of dry air. Wax, mucin, lysozyme, or beta-lactoglobulin did not influence significantly the rates of evaporation measured in vitro. In contrast, lipid layered on the surface resulted in a 23% decrease in the rates.
Environmental factors affect evaporation rates significantly and should be carefully controlled when performing in vivo measurements. The presence of a lipid layer lowers evaporation rates. The significantly lower rates of evaporation of tears measured in vivo suggest that with the lipid layer intact, the high reserve capacity of the lacrimal gland to provide both unstimulated and stimulated tear flow is more than enough to compensate for evaporative loss. However, with dry eye, increased rates of evaporation and decreased lacrimal tear flow could result in decreased break-up times.
Phenomenal new observations from Earth-based telescopes and Mars-based orbiters, landers, and rovers have dramatically advanced our understanding of the past environments on Mars. These include the ...first global-scale infrared and reflectance spectroscopic maps of the surface, leading to the discovery of key minerals indicative of specific past climate conditions; the discovery of large reservoirs of subsurface water ice; and the detailed in situ roving investigations of three new landing sites. This an important, new overview of the compositional and mineralogic properties of Mars since the last major study published in 1992. An exciting resource for all researchers and students in planetary science, astronomy, space exploration, planetary geology, and planetary geochemistry where specialized terms are explained to be easily understood by all who are just entering the field.
It is now widely accepted that the Internet and allied information communication technologies have facilitated small and medium enterprises' internationalisation. Moreover, as the World Wide Web (
...WWW
) has evolved, it has provided new tools that enable such firms to internationalise more rapidly and engage more effectively with customers in a wider range of more complex business activities. Within the last decade, significant advances in the
WWW
(Web 2.0), open-source architecture, and open-innovation strategies have led to the emergence of a 'new wave' of global firms. For these firms the Internet is a key driver of business development and speedy internationalisation. In this paper, having synthesised the literature on the Internet and rapid internationalisation and on open innovation, we discuss how these new-wave firms leverage value through close collaboration with other firms and co-creation with customers. Thereafter, we provide illustrative cases of these new-wave firms developed using Internet sources. These cases demonstrate how the focal firms have used Web 2.0 tools and techniques to leverage their internal and external capabilities, and become rapidly internationalising firms with fuzzy porous boundaries. Finally, we reflect upon the implications of Web 2.0 for business strategy, public policy, and academic enquiry, and propose an agenda for further research.
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