An evaluation of superminicomputers for thermal analysis

The feasibility and cost effectiveness of solving thermal analysis problems on superminicomputers is demonstrated. Conventional thermal analysis and the changing computer environment, computer hardware and software used, six thermal analysis test problems, performance of superminicomputers (CPU time, accuracy, turnaround, and cost) and comparison with large computers are considered. Although the CPU times for superminicomputers were 15 to 30 times greater than the fastest mainframe computer, the minimum cost to obtain the solutions on superminicomputers was from 11 percent to 59 percent of the cost of mainframe solutions. The turnaround (elapsed) time is highly dependent on the computer load, but for large problems, superminicomputers produced results in less elapsed time than a typically loaded mainframe computer

An evaluation of superminicomputers for thermal analysis

The use of superminicomputers for solving a series of increasingly complex thermal analysis problems is investigated. The approach involved (1) installation and verification of the SPAR thermal analyzer software on superminicomputers at Langley Research Center and Goddard Space Flight Center, (2) solution of six increasingly complex thermal problems on this equipment, and (3) comparison of solution (accuracy, CPU time, turnaround time, and cost) with solutions on large mainframe computers

The discovery of very red counterparts to faint X-ray sources

We present deep K-band imaging at the positions of four very faint X-ray sources found in the UK ROSAT Deep Survey to have no optical counterpart brighter than R~23. Likely identifications are found within the ROSAT error circle in all four fields with R-K colours of between 3.2 +/- 0.4 and 6.4 +/- 0.6. From a consideration of the R-K colours and X-ray to optical luminosity ratios of the candidate identifications, we tentatively classify two of the X-ray sources as very distant (z ~ 1) clusters of galaxies, one as a narrow emission line galaxy and one as an obscured QSO.Comment: 7 pages, LaTeX, 7 figures (1 postscript file each). Uses mn.sty and epsf.sty. Accepted by MNRAS. For more information see http://www.astro.soton.ac.uk/~amn/UKdee

Everyday ecocide, toxic dwelling, and the inability to mourn: a speculative response to geographies of extinction

In responding to the spatiotemporally specific geographies of extinction charted in the articles in this special section, this article reflects on the sociocultural factors that inform the ways in which extinction is framed and impede recognition of the enormity of the anthropogenic extinction event in which we are all bound. This article argues that we are living in an era of ecocide, where the degradation of biodiversity and eradication of species go hand-in-hand with the degradation and eradication of nonmodern culture and identity, and it explores some possible reasons why modern society is failing to respond to impending crisis. Fine-grained stories of spatiotemporally specific geographies of extinction can help to counter the logic of colonization and bring everyday ecocide into view. For the particular multispecies communities they concern, they can also feed into the creation of ritual practices of penitential mourning in ways that enable a collective grieving process poised to activate an ecosocial transformation. The authors consider the implications of grief and mourning—and of not mourning—in what can be seen as not only a terrible time but also the end of (lived) time. They conclude with some reflections of local acts of resistance, witnessing, and narrative

Trust and trustworthiness

What is it to trust someone? What is it for someone to be trustworthy? These are the two main questions that this paper addresses. There are various situations that can be described as ones of trust, but this paper considers the issue of trust between individuals. In it, I suggest that trust is distinct from reliance or cases where someone asks for something on the expectation that it will be done due to the different attitude taken by the trustor. I argue that the trustor takes Holton's 'participant stance' and this distinguishes trust from reliance. I argue that trustworthiness is different from reliability and that an account of trustworthiness cannot be successful whilst ignoring the point that aligning trustworthiness with reliability removes the virtue from being trustworthy. On the question of what it is distinguishes trustworthiness from reliability, I argue that the distinction is in the opportunity for the trustee to act against the wishes of the trustor and the trustee's consideration of the value of the trust that has been placed in them by the trustor

Focus on the Positives: Self-Supervised Learning for Biodiversity Monitoring

We address the problem of learning self-supervised representations from unlabeled image collections. Unlike existing approaches that attempt to learn useful features by maximizing similarity between augmented versions of each input image or by speculatively picking negative samples, we instead also make use of the natural variation that occurs in image collections that are captured using static monitoring cameras. To achieve this, we exploit readily available context data that encodes information such as the spatial and temporal relationships between the input images. We are able to learn representations that are surprisingly effective for downstream supervised classification, by first identifying high probability positive pairs at training time, i.e. those images that are likely to depict the same visual concept. For the critical task of global biodiversity monitoring, this results in image features that can be adapted to challenging visual species classification tasks with limited human supervision. We present results on four different camera trap image collections, across three different families of self-supervised learning methods, and show that careful image selection at training time results in superior performance compared to existing baselines such as conventional self-supervised training and transfer learning

Electrical activity of carbon-hydrogen centers in Si

The electrical activity of Cs-H defects in Si has been investigated in a combined modeling and experimental study. High-resolution Laplace capacitance spectroscopy with the uniaxial stress technique has been used to measure the stress-energy tensor and the results are compared with theoretical modeling. At low temperatures, implanted H is trapped as a negative-U center with a donor level in the upper half of the gap. However, at higher temperatures, H migrates closer to the carbon impurity and the donor level falls, crossing the gap. At the same time, an acceptor level is introduced into the upper gap making the defect a positive-U center

Error tolerance in an NMR Implementation of Grover's Fixed-Point Quantum Search Algorithm

We describe an implementation of Grover's fixed-point quantum search algorithm on a nuclear magnetic resonance (NMR) quantum computer, searching for either one or two matching items in an unsorted database of four items. In this new algorithm the target state (an equally weighted superposition of the matching states) is a fixed point of the recursive search operator, and so the algorithm always moves towards the desired state. The effects of systematic errors in the implementation are briefly explored.Comment: 5 Pages RevTex4 including three figures. Changes made at request of referees; now in press at Phys Rev

Molecular Evolution in Time Dependent Environments

The quasispecies theory is studied for dynamic replication landscapes. A meaningful asymptotic quasispecies is defined for periodic time dependencies. The quasispecies' composition is constantly changing over the oscillation period. The error threshold moves towards the position of the time averaged landscape for high oscillation frequencies and follows the landscape closely for low oscillation frequencies.Comment: 5 pages, 3 figures, Latex, uses Springer documentclass llncs.cl