Geochemical heterogeneity of sand deposits and its implications for the provenance determination of Roman glass

During the production of natron glass most features of the raw materials are lost and only some bulk geochemical characteristics have potential as provenance indicators. To determine the primary origin of archaeological glass artefacts, suitable sand raw materials have to be accurately characterised. In this respect, information about the possible variation in geochemical properties within a silica source is also vital to account for potential (partial) overlap of different sources. In this study, it is shown that the variation in major and minor elemental composition of beach sand on a local scale is smaller than the variation in Roman natron glass. Therefore, a single sand deposit can be seen as a relatively homogeneous source of silica for glass production. Nd isotopic signatures are identical for all samples analysed. The isotopic composition of Sr however varies considerably due to local variations in the relative proportions of carbonates and silicates (mostly feldspar).status: publishe

A two layer approach for ubiquitous web application development

The growing device diversity and anywhere/anytime nature of internet access calls for a new way of engineering web applications. These new paradigms introduce the need for context-awareness and personalization. In this paper we give the basis for two methods that can be used to bring web applications to almost every device and customise an application to the browsing user's profile and his device. We also present the basic design of a platform that interferes in the different layers of a web application and uses a modular approach and reflection as the basis for ubiquitous web applications

“Do we know each other or is it just our Devices?”: A Federated Context Model for Describing Social Activity Across Devices

The availability of connected devices is rapidly growing. In our everyday life, we already use a multitude of personal devices that are connected to the Internet. The number of shipped smart-phones at the end of 2010 even surpassed the traditional computer segments for the first time in the US [IDC]. From PC, to mobile, to home entertainment and even in-car units, consumers should be preparing for a connected experience

Do we know each other or is it just our devices? A federated context model for describing social activity across devices.

The availability of connected devices is rapidly growing. In our everyday life, we already use a multitude of personal devices that are connected to the Internet. The number of shipped smart-phones at the end of 2010 even surpassed the traditional computer segments for the first time in the US [IDC]. From PC, to mobile, to home entertainment and even in-car units, consumers should be preparing for a connected experience. At the same time rise of social media also had a major influence on how people communicate and collaborate. Applications such as Twitter, Facebook and YouTube have become the first place to go when there is breaking news. As devices turn web enabled, this evolution should allow us to connect the day-to-day activities of millions of users regardless of their location and regardless of the type of device they are using. The number of possible activities are endless and range from sending instant messages to friends, taking photographs, looking for deals online, navigating to our destination, reading newspapers and magazines, sharing content and sometimes even talking to others. However, as the web turns ubiquitous, all the more it becomes painfully apparent that we completely rely on dedicated applications in support of our needs. The web is everywhere, but we just can't live without our apps

Tracing the primary production location of core-formed glass vessels, Mediterranean Group I

Core-formed glass vessels of Mediterranean Group I were produced in the Mediterranean area between the sixth and fourth centuries BC. Indirect archaeological arguments have pointed to Rhodes as the primary glassmaking centre for these vessels. By comparing the elemental composition of hypothetical glasses produced from sand raw materials collected along the coastline of Rhodes to the reduced base glass composition of the core- formed vessels, it can be suggested that such sands are unsuitable for the production of these ancient glasses. Other locations in the Aegean area, i.e. Crete, Corinthia and central Macedonia, can also be largely excluded. A primary Syro-Palestinian provenance is more likely, based on the similarities in elemental and strontium/neodymium isotopic composition between the Mediterranean Group I glass vessels and raw glass chunks and sand raw materials originating from the Levant.status: publishe

Transcriptional dynamics of gametogenesis in the green seaweed Ulva mutabilis identifies an RWP-RK transcription factor linked to reproduction

Background: The molecular mechanism underlying sexual reproduction in land plants is well understood in model plants and is a target for crop improvement. However, unlike land plants, the genetic basis involved in triggering reproduction and gamete formation remains elusive in most seaweeds, which are increasingly viewed as an alternative source of functional food and feedstock for energy applications. Results: Gametogenesis of Ulva mutabilis, a model organism for green seaweeds, was studied. We analyzed transcriptome dynamics at different time points during gametogenesis following induction of reproduction by fragmentation and removal of sporulation inhibitors. Analyses demonstrated that 45% of the genes in the genome were differentially expressed during gametogenesis. We identified several transcription factors that potentially play a key role in the early gametogenesis of Ulva given the function of their homologs in higher plants and microalgae. In particular, the detailed expression pattern of an evolutionarily conserved transcription factor containing an RWP-RK domain suggested a key role during Ulva gametogenesis. Conclusions: Transcriptomic analyses of gametogenesis in the green seaweed Ulva highlight the importance of a conserved RWP-RK transcription factor in the induction of sexual reproduction. The identification of putative master regulators of gametogenesis provides a starting point for further functional characterization