Thinking in Islands; the Portuguese Perception of the Indonesian Archipelago and Particularly of Sunda in Early Texts and Charts

This article discusses various early sources on the Indonesian archipelago. It starts with the status of knowledge before the first voyage of the Portuguese to the Moluccas from accounts of travellers to insular Southeast Asia in the Middle Ages and the picture on world maps European cartographers produced. Comparing that view with text sources and the resulting geographic material of the first expeditions by the Portuguese provides an insight into contemporary mechanisms of knowledge transfer. Certain effects can be traced and are repeated on different levels of access to the original facts mainly because most maps were drawn up in Europe but based on the geographic description provided by text accounts. An abundance and multiplication of failures and mistakes is evident and is partly related to the scarcity of sources and due to reproduction techniques

Exploring block construction and mental imagery: Evidence of atypical orientation discrimination in Williams syndrome

The visuo-spatial perceptual abilities of individuals with Williams syndrome (WS) were investigated in two experiments. Experiment 1 measured the ability of participants to discriminate between oblique and between nonoblique orientations. Individuals with WS showed a smaller effect of obliqueness in response time, when compared to controls matched for non-verbal mental age. Experiment 2 investigated the possibility that this deviant pattern of orientation discrimination accounts for the poor ability to perform mental rotation in WS (Farran et al., 2001). A size transformation task was employed, which shares the image transformation requirements of mental rotation, but not the orientation discrimination demands. Individuals with WS performed at the same level as controls. The results suggest a deviance at the perceptual level in WS, in processing orientation, which fractionates from the ability to mentally transform images

Predictable execution of scientific workflows using advance resource reservations

Scientific Workflows are long-running and data intensive, and may encompass operations provided by multiple physically distributed service providers. The traditional approach to execute such workflows is to employ a single workflow engine which orchestrates the entire execution of a workflow instance, while being mostly agnostic about the state of the infrastructure it operates in (e.g., host or network load). Therefore, such centralized best-effort execution may use resources inefficiently -- for instance, repeatedly shipping large data volumes over slow network connections -- and cannot provide Quality of Service (QoS) guarantees. In particular, independent parallel executions might cause an overload of some resources, resulting in a performance degradation affecting all involved parties. In order to provide predictable behavior, we propose an approach where resources are managed proactively (i.e., reserved before being used), and where workflow execution is handled by multiple distributed and cooperating workflow engines. This allows to efficiently use the existing resources (for instance, using the most suitable provider for operations, and considering network locality for large data transfers) without overloading them, while at the same time providing predictability -- in terms of resource usage, execution timing, and cost -- for both service providers and customers. The contributions of this thesis are as follows. First, we present a system model which defines the concepts and operations required to formally represent a system where service providers are aware of the resource requirements of the operations they make available, and where (planned) workflow executions are adapted to the state of the infrastructure. Second, we describe our prototypical implementation of such a system, where a workflow execution comprises two main phases. In the planning phase, the resources to reserve for an upcoming workflow execution must be determined; this is realized using a Genetic Algorithm. We present conceptual and implementation details of the chromosome layout, and the fitness functions employed to plan executions according to one or more user-defined optimization goals. During the execution phase, the system must ensure that the actual resource usages abide to the reservations made. We present details on how such enforcement can be performed for various resource types. Third, we describe how these parts work together, and how the entire prototype system is deployed on an infrastructure based on WSDL/SOAP Web Services, UDDI Registries, and Glassfish Application Servers. Finally, we discuss the results of various evaluations, encompassing both the planning and runtime enforcement

Effective constraint potential in lattice Weinberg - Salam model

We investigate lattice Weinberg - Salam model without fermions for the value of the Weinberg angle $\theta_W \sim 30^o$, and bare fine structure constant around $\alpha \sim 1/150$. We consider the value of the scalar self coupling corresponding to bare Higgs mass around 150 GeV. The effective constraint potential for the zero momentum scalar field is used in order to investigate phenomena existing in the vicinity of the phase transition between the physical Higgs phase and the unphysical symmetric phase of the lattice model. This is the region of the phase diagram, where the continuum physics is to be approached. We compare the above mentioned effective potential (calculated in selected gauges) with the effective potential for the value of the scalar field at a fixed space - time point. We also calculate the renormalized fine structure constant using the correlator of Polyakov lines and compare it with the one - loop perturbative estimate.Comment: LATE

Thinking in Islands; The Portuguese perception of the Indonesian archipelago and particularly of Sunda in early texts and charts

This article discusses various early sources on the Indonesian archipelago. It starts with the status of knowledge before the first voyage of the Portuguese to the Moluccas from accounts of travellers to insular Southeast Asia in the Middle Ages and the picture on world maps European cartographers produced. Comparing that view with text sources and the resulting geographic material of the first expeditions by the Portuguese provides an insight into contemporary mechanisms of knowledge transfer. Certain effects can be traced and are repeated on different levels of access to the original facts mainly because most maps were drawn up in Europe but based on the geographic description provided by text accounts. An abundance and multiplication of failures and mistakes is evident and is partly related to the scarcity of sources and due to reproduction techniques.KeywordsPortuguese perception, Indonesian archipelago, Sunda, world maps, cartography, toponym

On the SU(2)-Higgs Phase Transition

The properties of the Confinement-Higgs phase transition in the SU(2)-Higgs model with fixed modulus are investigated. We show that the system exhibits a transient behavior up to L=24 along which the order of the phase transition cannot be discerned. To get stronger conclusions about this point, without going to prohibitive large lattice sizes, we have introduced a second (next-to-nearest neighbors) gauge-Higgs coupling, k2. On this extended parameter space we find a line of phase transitions which become increasely weaker as k2 tends to 0. The results point to a first order character for the transition with the standard action (k2 = 0).Comment: Replaced with revised version, some minor changes added. Accepted for publication in Nuc. Phys.