Tiarp Backgården. An Early Neolithic Dolmen in Falbygden, Sweden and Early Megalithic Tombs in South Scandinavia and Northern Central Europe

The excavation of the simple dolmen at Tiarp, Falbygden, dating to around 3500 BCE, has provided important information for the understanding of the megalithic and early TRB in southern Scandinavia and northern Central Europe. The absolute chronological dating shows that dolmens were erected at about the same time between Falbygden and Altmark, before the main passage grave architectural phase. Although fragmented and affected by taphonomic processes, the bone assemblage provides insights into the burial practices. At least twelve individuals, from neonates to elderly, had been buried within the chamber. The predominance of hand and foot bones suggests that they were primary inhumations. Their isotope values indicate an already agrarian society, which, however, was based only to a certain extent on agriculture. Insofar, the dolmen at Tiarp signals transformations – not only in respect to the introduction of agriculture but also regarding ritual practices – within the Early and Middle Neolithic

Accretion disc variability in the hard state of black hole X-ray binaries

XMM–Newton X-ray spectra of the hard state black hole X-ray binaries (BHXRBs) SWIFT J1753.5?0127 and GX 339?4 show evidence for accretion disc blackbody emission, in addition to hard power laws. The soft and hard band power spectral densities (PSDs) of these sources demonstrate variability over a wide range of time-scales. However, on time-scales of tens of seconds, corresponding to the putative low-frequency Lorentzian in the PSD, there is additional power in the soft band. To interpret this behaviour, we introduce a new spectral analysis technique, the 'covariance spectrum', to disentangle the contribution of the X-ray spectral components to variations on different time-scales. We use this technique to show that the disc blackbody component varies on all time-scales, but varies more, relative to the power law, on longer time-scales. This behaviour explains the additional long-term variability seen in the soft band. Comparison of the blackbody and iron line normalizations seen in the covariance spectra in GX 339?4 implies that the short-term blackbody variations are driven by thermal reprocessing of the power-law continuum absorbed by the disc. However, since the amplitude of variable reflection is the same on long and short time-scales, we rule out reprocessing as the cause of the enhanced disc variability on long time-scales. Therefore, we conclude that the long time-scale blackbody variations are caused by instabilities in the disc itself, in contrast to the stable discs seen in BHXRB soft states. Our results provide the first observational evidence that the low-frequency Lorentzian feature present in the PSD is produced by the accretion disc.<br/

Complex cattle exchange in the Scandinavian Funnel Beaker Culture. The case of Falbygden, Sweden

In this contribution, we highlight some of the results from analyses of cattle management at two Neolithic settlement sites in Falbygden, western Sweden. The two sites are located close to each other in the parish of Karleby in central Falbygden. Both were excavated 2012–2017 and yielded abundant animal bones, due to the calcareous bedrock. 14C datings indicate that they were both inhabited continuously during the period c. 3200–2900 BC, i.e. the Middle Neolithic Funnel Beaker (TRB) culture.Bulk and laser ablation strontium isotope ratios in cattle teeth from these settlements suggest a complex and wide-ranging system of animal exchange in the Scandinavian Middle Neolithic. More than half of the cattle found in the Karleby settlements were born outside the Falbygden region, and laser ablation suggests variable and individual trajectories through the landscape, in some cases involving areas in eastern Sweden. Further, origins of cattle at the two settlements are only partly overlapping, suggesting independent contact networks.We suggest an ongoing system of exchanges between settlement groups/social groups throughout Sweden to be behind this variability, rather than transhumance. This may in turn be motivated by a number of factors including biological herd viability, as well as social and economic factors

Selecting Software Component Sourcing Options : Detailed Survey Description and Analysis

Component-based software engineering (CBSE) is a common approach to develop and evolve contemporary software systems. When evolving a system based on components, make-or-buy decisions are frequent, i.e., whether to develop components internally or to acquire them fromexternal sources. In CBSE, several different sourcing options are available: 1) developing software in-house, 2) outsourcing development, 3) buying commercial-off-the-shelf software, and 4) integrating open source software components. Unfortunately, there is little available research on howorganizations select component sourcing options (CSO) in industry practice. In this work, we seek to contribute empirical evidence to CSO selection. Method: We conduct a cross-domain survey on CSO selection in industry, implemented as an online questionnaire. Based on 188 responses, we find that most organizations consider multiple CSOs during software evolution, and that the CSO decisions in industry are dominated by expert judgment. When choosing between candidate components, functional suitability acts as an initial filter, then reliability is the most important quality. We stress that future solution-oriented work on decision support has to account for the dominance of expert judgment in industry. Moreover, we identify considerable variation in CSO decision processes in industry. Finally, we encourage software development organizations to reflect on their decision processes when choosing whether to make or buy components, and we recommend using our survey for a first benchmarking.Orio

Selecting component sourcing options : A survey of software engineering's broader make-or-buy decisions

Context: Component-based software engineering (CBSE) is a common approach to develop and evolve contemporary software systems. When evolving a system based on components, make-or-buy decisions are frequent, i.e., whether to develop components internally or to acquire them from external sources. In CBSE, several different sourcing options are available: (1) developing software in-house, (2) outsourcing development, (3) buying commercial-off-the-shelf software, and (4) integrating open source software components. Objective: Unfortunately, there is little available research on how organizations select component sourcing options (CSO) in industry practice. In this work, we seek to contribute empirical evidence to CSO selection. Method: We conduct a cross-domain survey on CSO selection in industry, implemented as an online questionnaire. Results: Based on 188 responses, we find that most organizations consider multiple CSOs during software evolution, and that the CSO decisions in industry are dominated by expert judgment. When choosing between candidate components, functional suitability acts as an initial filter, then reliability is the most important quality. Conclusion: We stress that future solution-oriented work on decision support has to account for the dominance of expert judgment in industry. Moreover, we identify considerable variation in CSO decision processes in industry. Finally, we encourage software development organizations to reflect on their decision processes when choosing whether to make or buy components, and we recommend using our survey for a first benchmarking. © 201