Specific ant-pollination in an alpine orchid and the role of floral scent in attracting pollinating ants

Several studies have recently shown that floral scent can deter ants from flowers. However, when ants serve as reliable pollen vectors, for example in harsh, windy habitats, were flying insects are less active, plants should have evolved floral signals to attract them to the flowers. We tested this hypothesis in the alpine orchid, Chamorchis alpina. C. alpina was found to be predominantly ant pollinated, with some occasional pollination by ichneumonid wasps. In all three investigated populations, only two species of ants, Formica lemani and Leptothorax acervorum visited the flowers and removed pollinaria. These two pollinator ants were found to be among the most common ant species in all habitats, but other, non-pollinating ants were also frequently found, suggesting a factor that mediates specific pollination. Floral morphology was found to be compatible with at least one of the common non-pollinator ants. Floral scent consistently comprised five terpenoid compounds, β-phellandrene, 1,8-cineole, linalool, α-terpineol, and β-caryophyllene. A synthetic blend of these five compounds emitting from rubber septa, was found to be attractive to one pollinator ant-species, F. lemani, in the field. The floral scent of C. alpina, through attracting only specific ants, may thus play a role in filtering floral visitor

Distribution, nest densities and ecology of moundbuilding wood ants of the genus Formica in the Tyrolean wood

Trotz der erheblichen waldökologischen und naturschutzfachlichen Bedeutung hügelbauender Formica-Arten waren Informationen über aktuelle Verbreitung, ökologische Einnischung und eventuelle Gefährdung in Tirol als lückenhaft zu bezeichnen. Aus diesem Grund wurde in enger Zusammenarbeit mit der Landesforstdirektion Tirol und im Auftrag der Tiroler Landesregierung, Abtlg. Umweltschutz, eine landesweite Erhebung des Waldameisenbestandes im Zuge routinemäßig durchgeführter forstlicher Inventuren von 2004 bis 2006 durchgeführt (Glaser 2004, 2005, 2006). Dabei ergab die Analyse der Waldameisenbesiedlung in Abhängigkeit zu ebenfalls erhobenen forstlicher Parameter Hinweise auf die Habitatpräferenzen einzelner Arten.Mound building Formica species were mapped during routine forestry inventories across the whole federal country of Tyrol (Austria) from 2004 to 2006. A total number of 8 species was collected. Formica aquilonia shows maximal mean densities (2,41 nests / ha) and frequencies (21,1 %). F. lugubris and F. paralugubris reach mean densities above 0,15 nests / ha. All other species are relatively rare. The mean nest density in all 1152 plots is 3 nests / ha. F. aquilonia shows maximal densities during a woodland age of 80 to 160 years. F. lugubris is more frequent in younger stands (40 – 60 a) and older stands (180 – 200 a). F. sanguinea and F. polyctena prefer young woodland (< 40 a). Densities of all wood ants and of F. aquilonia are positively correlated to woodland age, the density of F. polyctena is negatively correlated to woodland age. Species number of wood ants decreases in a woodland age of 60 – 100 years. The observed patterns are explained by the strong influence of insolation on the distribution of wood ants and their important host species (Formica lemani, F. fusca) as well as species specific ability of colony budding

Pervasive Decentralisation of Digital Infrastructures: A Framework for Blockchain enabled System and Use Case Analysis

Technological innovation and consequential decentralisation are driving forces in the ongoing evolution and increasing openness of digital infrastructures and services. One of the most discussed and allegedly disruptive innovations is the distributed database technology referred to as blockchain. Although it is still in its technological infancy, experimental adoption and customization seem to be in full progress in various potential fields of application ranging from decentralized grids for computation and storage to global financial services. However, the technology and its path of development still entail a lot of common unknowns for practitioners and researchers alike. Especially regarding the question how the technology could amend or be incorporated into the existing landscape of digital services, processes and infrastructures. Hence, in this article we develop an ontology that (1) clearly delineates common terminology, core concepts and components, their relationships as well as innovative features of blockchain technology. It further (2) connects these insights with implications for relevant types of digital market models. Our framework is of high theoretical and practical value as it provides researchers and practitioners a common basis for communication and means for guided analysis of blockchain applicability

The side effect of scrutinising traders in social trading platforms

Increased transparency in investor/trader relationships induces behavioural biases, write Florian Glaser and Marten Risiu

Towards an Economic Analysis of Routing in Payment Channel Networks

Payment channel networks are supposed to overcome technical scalability limitations of blockchain infrastructure by employing a special overlay network with fast payment confirmation and only sporadic settlement of netted transactions on the blockchain. However, they introduce economic routing constraints that limit decentralized scalability and are currently not well understood. In this paper, we model the economic incentives for participants in payment channel networks. We provide the first formal model of payment channel economics and analyze how the cheapest path can be found. Additionally, our simulation assesses the long-term evolution of a payment channel network. We find that even for small routing fees, sometimes it is cheaper to settle the transaction directly on the blockchain.Comment: 6 pages, 3 figures, SERIAL '17 Worksho

Beyond Cryptocurrencies - A Taxonomy of Decentralized Consensus Systems

The advent of Bitcoin in 2009 has not only introduced Cryptocurrencies and lead to a new digitization movement in the financial, especially payments industry but also made way for a new breed of innova-tive technologies based on decentralized digital currencies. Generally, decentralized consensus sys-tems could change the very nature of how companies, organizations and individuals are built and in-teract with each other. Decentralized consensus systems, decentralized applications and smart con-tracts provide the conceptual framework as well as the technological basis to establish predefined, incorruptible protocols and contracts to organize human behavior and interconnectedness. However, the technical protocols and implementations are quite complex and practitioners as well as interdisci-plinary researchers not familiar with cryptography, network protocols or decentralized networks are struggling to find access to these concepts and grasp their potential. To fill this gap, we develop a comprehensive taxonomy of decentralized consensus systems in order to provide a tool for researchers and practitioners alike to facilitate classification and analysis of emerging technologies in the field of Crypto 2.0 , the next level of innovation beyond cryptocurrencies

An 826 MOPS, 210 uW/MHz Unum ALU in 65 nm

To overcome the limitations of conventional floating-point number formats, an interval arithmetic and variable-width storage format called universal number (unum) has been recently introduced. This paper presents the first (to the best of our knowledge) silicon implementation measurements of an application-specific integrated circuit (ASIC) for unum floating-point arithmetic. The designed chip includes a 128-bit wide unum arithmetic unit to execute additions and subtractions, while also supporting lossless (for intermediate results) and lossy (for external data movements) compression units to exploit the memory usage reduction potential of the unum format. Our chip, fabricated in a 65 nm CMOS process, achieves a maximum clock frequency of 413 MHz at 1.2 V with an average measured power of 210 uW/MHz

Nudged to Win: Designing Robo-Advisory to Overcome Decision Inertia

Decision inertia is a serious problem in financial decision-making and thus a challenge for decision support systems. We discuss recent findings and review antecedents and consequences of decision inertia from a psychological perspective. We use these insights to develop IT-based methods designed to overcome decision inertia using psychologically optimized financial decision support systems. Furthermore, we propose an experimental study to evaluate the design features of such a system. Our work is a first step in designing adaptive decision support systems that detect situations in which the user is prone to decision inertia and react by adapting interface elements appropriately that might otherwise exacerbate decision inertia – for a specific user in a specific decision situation