Social Networks as Trojan Horses to Challenge the Dominance of Existing Hierarchies: Knowledge and Learning in the Water Governance of Volos, Greece

In context of the implementation of the EU Water Framework Directive, conventional hierarchies and dominant logics in the metropolitan area of Volos, Greece, are challenged indirectly, in a “Trojan-horse” like way. The basic characteristic of the water sector in Volos Urban Area is the absolute dominance of centralized services (Municipal Enterprise for Water and Sewage). However, the intense interest of new actors (private companies, NGOs, University and Research Institutes, etc.) has led to the establishment of an informal and voluntary social network. The paper evaluates the role of an informal social network as a new form of governance in the framework of spatial development that has emerged in the shadow of an existing hierarchy. The basic issues highlighted are:

• The challenge to hierarchical decision making structures in the water sector through an informal and voluntary social network.
• The learning processes and knowledge forms that new actors bring to and acquire in such forms of network practices (e.g. contribution to public awareness, mobilisation of local knowledge).

     

Association control algorithms for handoff frequency minimization in mobile wireless networks

As mobile nodes roam in a wireless network, they continuously associate with different access points and perform handoff operations. Frequent handoffs performed by a mobile device may have undesirable consequences, as they can cause interruptions for interactive applications and increase the energy usage of mobile devices. While existing approaches to this issue focus entirely on improving the latency incurred by individual handoffs, in this paper, we initiate a novel approach to association control of mobile devices with the goal of reducing the frequency of handoffs for mobile devices. We study the handoff minimization problem across multiple dimensions: offline versus online where the complete knowledge of mobility patterns of users is known in advance or unknown respectively; capacity constrained versus unconstrained access points, which imposes limits on the number of mobile devices which could be associated with a given access point at any given point in time; group mobility versus arbitrary mobility of users, which are contrasting ways to model the mobility patterns of the mobile users. We consider various combinations of the above dimensions and present the following: (1) optimal algorithms, (2) provably-good online and offline approximation algorithms, (3) complexity (NP-Completeness) results, and (4) a practical heuristic which is demonstrated to work well on real network traces.     

High-level customization framework for application-specific NoC architectures

Network-on-Chip (NoC) has been recognized as the new paradigm to interconnect and organize a high number of cores. NoCs address global communication issues in System-on-Chips (SoC) involving communication-centric design and implementation of scalable communication structures evolving application-specific NoC design as a key challenge to modern SoC design. In this paper we present a SystemC customization framework and methodology for automatic design and evaluation of regular and irregular NoC architectures. The presented framework also supports application-specific optimization techniques such as priority assignment, node clustering and buffer sizing. Experimental results show that generated regular NoC architectures achieve an average of 5.5 % lower communication-cost compared to other regular NoC designs while irregular NoCs proved to achieve on average 4.5×higher throughput and 40 % network delay reduction compared to regular mesh topologies. In addition, employing a buffer sizing algorithm we achieve a reduction in network’s power consumption by an average of 45 % for both regular and irregular NoC design flow.     

In vivo anti-atherogenic properties of cultured gilthead sea bream (Sparus aurata) polar lipid extracts in hypercholesterolaemic rabbits

The aim of this study was to investigate whether the fish lipid extracts have in vivo anti-atherogenic properties in hypercholesterolaemic rabbits. Fish oil extracts were obtained from cultured gilthead sea bream (Sparus aurata) and, for the in vivo experiment, 12 healthy male New Zealand rabbits of specific weight and age were used, which were randomly divided into two groups of six animals each and were given specific diets for 45 days. Group A was given an atherogenic diet, while group B was given an atherogenic diet enriched with Gilthead Sea Bream Polar Lipids (GSBPL).     

Kinetics of endoglucanase and endoxylanase uptake by soybean seeds

The uptakes of endoglucanase and endoxylanase by soybean were studied by measuring the fluorescent intensity of a carboxyfluorescein. The disappearance rates of these enzymes from solution were compared with predictions from different models. The Freundlich model provided the best fit for our data. Enzyme concentration in the solution did not change significantly after 11 d, and therefore it was assumed that equilibrium was reached. Average mass transfer coefficient was calculated for both endoglucanase and endoxylanase from the plot of the rate of uptake against (C(l av) -Cl*) and a value of 4 x 10(-5) ms(-1) was obtained. K value was used to calculate the effective diffusivities of the two enzymes assuming a slice. It is found that K was asymptotic with long residence times, and a value of 4.8 x 10(-10) m2 s(-1) was obtained.     

Growth of Aeromonas hydrophila in the whey cheeses Myzithra, Anthotyros, and Manouri during storage at 4 and 12 degrees C

The fresh whey cheeses Myzithra, Anthotyros, and Manouri were inoculated with Aeromonas hydrophila strain NTCC 8049 (type strain) or with an A. hydrophila strain isolated from food (food isolate) at levels of 3.0 to 5.0 x 10(2) CFU/g of cheese and stored at 4 or 12 degrees C. Duplicate samples of cheeses were tested for levels of A. hydrophila and pH after up to 29 days of storage. At 4 degrees C, A. hydrophila grew in Myzithra and Anthotyros with a generation time of ca. 19 h, but no growth was observed in Manouri. In Myzithra, average maximum populations of 8.87 log CFU/g (type strain) and 8.79 log CFU/g (food isolate) were recorded after 20 and 22 days of storage at 4 degrees C, respectively. The average maximum populations observed in Anthotyros stored at 4 degrees C were 6.72 log CFU/g (food isolate) and 6.13 log CFU/g (type strain) and were observed after 15 and 16 days of storage, respectively. A. hydrophila grew rapidly and reached high numbers in cheeses stored at 12 degrees C. The average generation times were 3.7 and 3.9 h (Myzithra), 4.1 and 6.1 h (Anthotyros), and 8.0 and 9.2 h (Manouri) for the type strain and the food isolate, respectively. Among the different whey cheese trials, the highest A. hydrophila population recorded (10.13 log CFU/g) was in Myzithra that had been inoculated with the food isolate after 8 days of storage at 12 degrees C. To prevent A. hydrophila growth in whey cheeses, efforts must be focused on preventing postprocessing contamination and temperature abuse during transportation and storage.     

Carbon nanotubes encapsulating superconducting single-crystalline tin nanowires

Superconducting low dimensional systems are the natural choice for fast and sensitive infrared detection, because of their quantum nature and the low-noise, cryogenic operation environment. On the other hand, monochromatic and coherent electron beams, emitted from superconductors and carbon-based nanostructured materials, respectively, are significant for the development of electron optical systems such as electron microscopes and electron-beam nanofabrication systems. Here we describe for the first time a simple method which yields carbon nanotubes encapsulating single crystalline superconducting tin nanowires by employing the catalytic chemical vapor deposition method over solid tin dioxide. The superconducting tin nanowires, with diameters 15-35 nm, are covered with well-graphitized carbon walls and show, due to their reduced diameters, a critical magnetic field (Hc) more than 30 times higher than the value of bulk metallic tin.     

Average Case Analysis of Searching in Associative Processing

We introduce an average case analysis of the search primitive operations (equality and thresholding) in associative memories. We provide a general framework for analysis, using as parameters the word space distribution and the CAM size parameters:m(number of memory words) andn(memory word length). Using this framework, we calculate the probability that the whole CAM memory responds to a search primitive operation after comparing up tokmost significant bits (1?k?n) in each word; furthermore, we provide a closed formula for the average value ofkand the probability that there exists at least one memory word that equals the centrally broadcast word. Additionally, we derive results for the cases of uniform and exponential distribution of word spaces. We prove that in both cases the average value ofkdepends strongly on lg m, whenn>lg m: for the case of uniform distribution, the average value is practically independent ofn, while in the exponential depends weakly on the difference between the sample space size 2ⁿand the CAM sizem. Furthermore, in both cases, the averagekis approximatelynwhenn?lg m. Verification of our theoretical results through massive simulations on a parallel machine is presented. One of the main results of this work, that the average value ofkcan be much smaller than n or even practically independent ofnin some cases, has an important practical effect: associative memories can be designed with fast execution times of threshold primitives and low implementation complexity, leading to high performance associative memories that can scale up to sizes larger than previous designs at a low cost.     

Resource management in Legion

The recent development of gigabit networking technology, combined with the proliferation of low-cost, high-performance microprocessors, has given rise to metacomputing environments. These environments can combine many thousands of hosts, from hundreds of administrative domains, connected by transnational and world-wide networks. Managing the resources in such a system is a complex task, but is necessary to efficiently and economically execute user programs.

In this paper, we describe the resource management portions of the Legion metacomputing system, including the basic model and its implementation. These mechanisms are flexible both in their support for system-level resource management but also in their adaptability for user-level scheduling policies. We show this by implementing a simple scheduling policy and demonstrating how it can be adapted to more complex algorithms.