A Parallel Tree-SPH code for Galaxy Formation

We describe a new implementation of a parallel Tree-SPH code with the aim to simulate Galaxy Formation and Evolution. The code has been parallelized using SHMEM, a Cray proprietary library to handle communications between the 256 processors of the Silicon Graphics T3E massively parallel supercomputer hosted by the Cineca Supercomputing Center (Bologna, Italy). The code combines the Smoothed Particle Hydrodynamics (SPH) method to solve hydro-dynamical equations with the popular Barnes and Hut (1986) tree-code to perform gravity calculation with a NlogN scaling, and it is based on the scalar Tree-SPH code developed by Carraro et al(1998)[MNRAS 297, 1021]. Parallelization is achieved distributing particles along processors according to a work-load criterion. Benchmarks, in terms of load-balance and scalability, of the code are analyzed and critically discussed against the adiabatic collapse of an isothermal gas sphere test using 20,000 particles on 8 processors. The code results balanced at more that 95% level. Increasing the number of processors, the load-balance slightly worsens. The deviation from perfect scalability at increasing number of processors is almost negligible up to 32 processors. Finally we present a simulation of the formation of an X-ray galaxy cluster in a flat cold dark matter cosmology, using 200,000 particles and 32 processors, and compare our results with Evrard (1988) P3M-SPH simulations. Additionaly we have incorporated radiative cooling, star formation, feed-back from SNae of type II and Ia, stellar winds and UV flux from massive stars, and an algorithm to follow the chemical enrichment of the inter-stellar medium. Simulations with some of these ingredients are also presented.Comment: 19 pages, 14 figures, accepted for publication in MNRA

Bible Software on the Workbench of the Biblical Scholar: Assessment and Perspective

This article pursues two objectives. First, it tries to explain why Bible software is still not accepted as an indispensable tool for textual analysis. Second, it suggests that modern Hebrew databases can truly impact the analytic methodology of biblical scholars and help to verify and falsify interpretative suggestions. To achieve these two objectives, I will first describe the role Bible software plays in today’s scholarship. By contrasting the aids that Bible software offers with the analytic needs of biblical scholars, it is possible to show clearly what current electronic tools need if they are to play an essential methodological role in the analytic work of the scholar. The second part of the article will then illustrate, in some detail, what the Hebrew database of the Eep Talstra Centre of Bible and Computer (ETCBC) could offer today to the Old Testament scholar and how a future implementation into Bible software could deliver an electronic tool that becomes indispensable for Old Testament scholarship

Personal Reflections on Supervision as Instructional Leadership: From Whence It Came and To Where Shall It Go?

The field of supervision has perennially struggled to define itself and, hence, find a niche within the larger field of education and, more narrowly, even within the field of instructional leadership. A sort of an odd, almost contradictory state exists, one in which precludes, in my opinion, the field of supervision from gaining traction as a field, but also, perhaps more importantly, as an influential practice in schools. Books on supervision seem popular, but only in title. In others words, publishers, for instance, prefer the word supervision as part of the title of books they publish on the subject, whereas scholars in the field tend to eschew the term in favor of a term, perhaps, more palatable such as instructional or pedagogical leadership. Scholars in our field have had to grapple with this bifurcation. This essay discusses some of the implications of the intractable nature of supervision theory and practice and its relationship with the emergence of newer, more preferred terms. This essay attempts to clarify the relationships among supervision, instructional leadership, pedagogical leadership, and some other terms bandied about in the field. Are there differences between and among them? What are the implications for the field of supervision, as well as for the world of practice