Reconstructing mid-to-recent Holocene paleoenvironments in the vicinity of ancient Amarynthos (Euboea, Greece).

This article examines the shoreline evolution and human occupation in the vicinity of the important archeological site of Amarynthos (Euboea Island, Greece) over the last six millennia. Archeological evidence indicates a continuous occupation of the site from the Bronze Age to the Roman period and the site is well-known, thanks to the existence of a sanctuary dedicated to the goddess Artemis. Based on the study of four boreholes, a paleogeographic reconstruction of the coastal landscape is proposed. Facies were determined based on mollusc identification, and sedimentology based on grain-size measurements (hand sieving for the fraction above 2 mm and LASER technique for particles below 2 mm) and loss-on-ignition. In addition, a series of 12 AMS radiocarbon dates define a reliable chronostratigraphy. Results suggest the presence of a fully marine environment from the early Holocene to ca. 2600-2400 cal. BC, which developed into a brackish environment from ca. 2600-2400 cal. BC to ca. 750 cal. BC due to the deltaic progradation of the nearby stream (Sarandapotamos River). From ca. 750 cal. BC onward, coastal swamps prevailed in the study area. Human-environmental interaction is discussed and particular attention is paid to the paleolandscape configuration of Amarynthos.

An architecture for adaptive replication-based multimedia streaming in P2P networks

This PhD thesis addresses the issue of scalable media streaming in large-scale networking environments. Multimedia streaming is one of the largest sink of network resources and this trend is still growing as testified by the success of services like Skype, Netflix, Spotify and Popcorn Time (BitTorrent-based). In traditional client-server solutions, when the number of consumers increases, the server becomes the bottleneck. To overcome this problem, the Content-Delivery Network (CDN) model was invented. In CDN model, the server copies the media content to some CDN servers, which are located in different strategic locations on the network. However, they require heavy infrastructure investment around the world, which is too expensive. Peer-to-peer (P2P) solutions are another way to achieve the same result. These solutions are naturally scalable, since each peer can act as both a receiver and a forwarder. Most of the proposed streaming solutions in P2P networks focus on routing scenarios to achieve scalability. However, these solutions cannot work properly in video-on-demand (VoD) streaming, when resources of the media server are not sufficient. Replication is a solution that can be used in these situations. This thesis specifically provides a family of replication-based media streaming protocols, which are scalable, efficient and reliable in P2P networks. First, it provides SCALESTREAM, a replication-based streaming protocol that adaptively replicates media content in different peers to increase the number of consumers that can be served in parallel. The adaptiveness aspect of this solution relies on the fact that it takes into account different constraints like bandwidth capacity of peers to decide when to add or remove replicas. SCALESTREAM routes media blocks to consumers over a tree topology, assuming a reliable network composed of homogenous peers in terms of bandwidth. Second, this thesis proposes RESTREAM, an extended version of SCALESTREAM that addresses the issues raised by unreliable networks composed of heterogeneous peers. Third, this thesis proposes EAGLEMACAW, a multiple-tree replication streaming protocol in which two distinct trees, named EAGLETREE and MACAWTREE, are built in a decentralized manner on top of an underlying mesh network. These two trees collaborate to serve consumers in an efficient and reliable manner. The EAGLETREE is in charge of improving efficiency, while the MACAWTREE guarantees reliability. Finally, this thesis provides TURBOSTREAM, a hybrid replication-based streaming protocol in which a tree overlay is built on top of a mesh overlay network. Both these overlays cover all peers of the system and collaborate to improve efficiency and low-latency in streaming media to consumers. This protocol is implemented and tested in a real networking environment using PlanetLab Europe testbed composed of peers distributed in different places in Europe.

Ancient kings of Peru : the reliability of the Chronicle of Fernando de Montesinos

Doctoral dissertation, University of Turku

Hidden branches: developments in root system architecture.

The root system is fundamentally important for plant growth and survival because of its role in water and nutrient uptake. Therefore, plants rely on modulation of root system architecture (RSA) to respond to a changing soil environment. Although RSA is a highly plastic trait and varies both between and among species, the basic root system morphology and its plasticity are controlled by inherent genetic factors. These mediate the modification of RSA, mostly at the level of root branching, in response to a suite of biotic and abiotic factors. Recent progress in the understanding of the molecular basis of these responses suggests that they largely feed through hormone homeostasis and signaling pathways. Novel factors implicated in the regulation of RSA in response to the myriad endogenous and exogenous signals are also increasingly isolated through alternative approaches such as quantitative trait locus analysis.

Hometown architecture : changes in Central Iowa towns and farms,1981.

This book is a product of a two year project, the extensive surveys CIRALG and the Division of Historic Preservation undertook to identify culturally significant structures in central Iowa. It discloses the aspirations, tastes, building abilities and needs of earlier Iowans.