Optimizing Circular Side-Resonators to Reduce Computer Fan Noise

One of the main noise sources in computers are the cooling fans. Tonal noise at the rotational frequency of the fan, the blade passing frequency (BPF) and its higher harmonics are important in fan noise. So called 'side-resonators' integrated in the duct of an in-duct axial fan cause an impedance change in the duct and, having proper dimensions and correct position, act as an acoustic mirror reflecting the noise back to the fan. As a result, noise emitted from the computer can be reduced. In this paper, a model describing viscothermal wave propagation in the duct and side-resonator is outlined. The model can be used to determine the resonator dimension and position to optimally reflect noise near the BPF. The developed model is compared with the models for prismatic tube and cylindrical resonators and the physical differences between these three resonators are explained. Preliminary results of a parameter study are presented. The results point out that the range and magnitude of the effective frequency band of a resonator setup can be successfully manipulated by changing the different dimensions of the setup

The infrared counterpart to the magnetar 1RXS J170849.0-400910

We have analyzed both archival and new infrared imaging observations of the field of the Anomalous X-ray Pulsar 1RXS J170849.0-400910, in search of the infrared counterpart. This field has been previously investigated, and one of the sources consistent with the position of the AXP suggested as the counterpart. We, however, find that this object is more likely a background star, while another object within the positional error circle has non-stellar colors and shows evidence for variability. These two pieces of evidence, along with a consistency argument for the X-ray-to-infrared flux ratio, point to the second source being the more likely infrared counterpart to the AXP.Comment: 19 pages AASTEX, 4 figure. Accepted for publication in ApJ. Full resolution figures at: http://www.astro.utoronto.ca/~durant/1708.ps.g

Consistency in Multi-Viewpoint Architectural Design of Enterprise Information Systems

Different stakeholders in the design of an enterprise information system have their own view on that design. To help produce a coherent design this paper presents a framework that aids in specifying relations between such views. To help produce a consistent design the framework also aids in specifying consistency rules that apply to the view relations and in checking the consistency according to those rules. The framework focuses on the higher levels of abstraction in a design, we refer to design at those levels of abstraction as architectural design. The highest level of abstraction that we consider is that of business process design and the lowest level is that of software component design. The contribution of our framework is that it provides a collection of basic concepts that is common to viewpoints in the area of enterprise information systems. These basic concepts aid in relating viewpoints by providing: (i) a common terminology that helps stakeholders to understand each others concepts; and (ii) a basis for defining re-usable consistency rules. In particular we define re-usable rules to check consistency between behavioural views that overlap or are a refinement of each other. We also present an architecture for a tool suite that supports our framework. We show that our framework can be applied, by performing a case study in which we specify the relations and consistency rules between the RM-ODP enterprise, computational and information viewpoints

The Hansenula polymorpha PER8 Gene Encodes a Novel Peroxisomal Integral Membrane Protein Involved in Proliferation

We previously described the isolation of mutants of the methylotrophic yeast Hansenula polymorpha that are defective in peroxisome biogenesis. Here, we describe the characterization of one of these mutants, per8, and the cloning of the PER8 gene. In either methanol or methylamine medium, conditions that normally induce the organdies, per8 cells contain no peroxisome-like structures and peroxisomal enzymes are located in the cytosol. The sequence of PER8 predicts that its product (Per8p) is a novel polypeptide of 34 kD, and antibodies against Per8p recognize a protein of 31 kD. Analysis of the primary sequence of Per8p revealed a 39-amino-acid cysteine-rich segment with similarity to the C3HC4 family of zinc-finger motifs. Overexpression of PER8 results in a markedly enhanced increase in peroxisome numbers. We show that Per8p is an integral membrane protein of the peroxisome and that it is concentrated in the membranes of newly formed organdies. We propose that Per8p is a component of the molecular machinery that controls the proliferation of this organelle.

The Effect of Improved School Climate Over Time on Fifth-Grade Students’ Achievement Assessment Scores and Teacher Administered Grade Scores

The purpose of the study was to determine the effect of improved school climate, as teachers\u27 beliefs changed from negative to positive over time, on students\u27 reading, math, and writing assessment scores and teacher administered grade scores in reading, math, and writing. Overall, findings indicate that lose, maintain, or improve third-grade pretest compared to fifth-grade posttest Essential Learner Outcome assessment below proficient, barely proficient, proficient, or beyond proficient nomenclature category chi-square results were in the direction of statistically different nomenclature category improvement for reading ( X2 (6, N = 75) = 22.00, p = .001), math (X2 (6, N = 75) = 69.20, p = .000), and writing ( X2 (6, N = 75) = 18.60, p = .005) indicating that fifth-grade posttest Essential Learner Outcome assessment scores were positively impacted by an improving school climate with the majority of the students improving or maintaining their proficiency level. Furthermore, lose, maintain, or improve ending of third-grade pretest compared to ending fifth-grade posttest grade chi-square results were in the direction of statistically different improvement for reading grade score results ( X2 (6, N = 75) = 30.30, p = .000), math grade score results (X2 (6, N = 75) = 14.00, p = .030), and writing grade score results (X2 (6, N = 75) = 35.20, p = .000) indicating that fifth-grade posttest reading grade scores were positively impacted by an improving school climate with the majority of the students improving or maintaining their grade score. School climate is an essential factor in students\u27 academic, social, emotional, and ethical development and wellbeing. Students who experience a sense of safety, have healthy adult and peer relationships, feel respected, and are encouraged to take ownership in creating a positive school climate are well on their way to becoming productive citizens with the academic resources necessary to make a positive difference in their own lives--and the lives of others in their school community as well

A Rigorous Approach to Relate Enterprise and Computational Viewpoints

Multiviewpoint approaches allow stakeholders to design a system from stakeholder-specific viewpoints. By this, a separation of concerns is achieved, which makes designs more manageable. However, to construct a consistent multiviewpoint design, the relations between viewpoints must be defined precisely, so that the consistency of designs from these viewpoints can be verified. The goal of this paper is to make the consistency rules between (a slightly adapted version of) the RM-ODP enterprise and computational viewpoints more precise and to make checking the consistency between these viewpoints practically applicable. To achieve this goal, we apply a generic framework for relating viewpoints that includes reusable consistency rules. We implemented the consistency rules in a tool to show their applicability