Survey of fish protective facilities at water withdrawal sites on the Snake and Columbia Rivers

Proliferation of water withdrawals and new pump intake and screen designs has occurred with the growth of irrigated agriculture along the Columbia and Snake Rivers. Concern for the protection of anadromous and resident fish populations resulted in formulation of a survey of the water withdrawal systems. The survey included distribution studies of juvenile fish near pump sites and field inspection of those sites to determine adequacy of screening for protection of fish. A total of 225 sites were inspected in 1979 and 1980, with a follow-up inspection of 95 sites in 1982. Results indicated a definite trend toward lack of concern for the condition of fish protective facilities. Only 4 out of 22 sites not meeting criteria in 1979 had been upgraded to acceptable conditions. Of more concern, 13 of the sites meeting criteria in 1979 were below criteria when reinspected in 1982. Some of the discrepancies included lack of protective screens, poorly maintained screens, and screens permitting excessive velocity that could result in impingement of larvae or small fish. A conclusion from these surveys is that if adequate protection for fish is to exist, screens for water withdrawals need to be properly installed, inspected, and maintained. (PDF file contains 40 pages.

The unbiased frequency of planetary signatures around single and binary white dwarfs using Spitzer{\it Spitzer} and Hubble{\it Hubble}

This paper presents combined ${\it Spitzer}$ IRAC and ${\it Hubble}$ COS results for a double-blind survey of 195 single and 22 wide binary white dwarfs for infrared excesses and atmospheric metals. The selection criteria include cooling ages in the range 9 to 300 Myr, and hydrogen-rich atmospheres so that the presence of atmospheric metals can be confidently linked to ongoing accretion from a circumstellar disc. The entire sample has infrared photometry, whereas 168 targets have corresponding ultraviolet spectra. Three stars with infrared excesses due to debris discs are recovered, yielding a nominal frequency of $1.5_{-0.5}^{+1.5}$ per cent, while in stark contrast, the fraction of stars with atmospheric metals is $45\pm4$ per cent. Thus, only one out of 30 polluted white dwarfs exhibits an infrared excess at 3-4 $\mu$m in IRAC photometry, which reinforces the fact that atmospheric metal pollution is the most sensitive tracer of white dwarf planetary systems. The corresponding fraction of infrared excesses around white dwarfs with wide binary companions is consistent with zero, using both the infrared survey data and an independent assessment of potential binarity for well-established dusty and polluted stars. In contrast, the frequency of atmospheric pollution among the targets in wide binaries is indistinct from apparently single stars, and moreover the multiplicity of polluted white dwarfs in a complete and volume-limited sample is the same as for field stars. Therefore, it appears that the delivery of planetesimal material onto white dwarfs is ultimately not driven by stellar companions, but by the dynamics of planetary bodies.Comment: 15 pages, 6 figures, 3 tables; accepted for publication in MNRA

An IoT and Blockchain-based Approach for Ensuring Transparency and Accountability in Regulatory Compliance

Regulatory compliance is an essential exercise in the modern societies confirming safety and prevention of harm to consumers. Despite many efforts from international and national quality control authorities, transparency and accountability in regulatory compliance remain a challenging technical-legal problem sitting atop a heavy reliance on trust. This paper presents a theoretical model of regulatory compliance aiming at improving accountability for systems and data audit and introduces a higher degree of transparency in management and quality control. It explores the technical aspects of two emerging technologies the Internet of Things (IoT) and Blockchain, and using a common use-case in practice shows how to better align these technologies with legal concerns and trust in regulatory compliance

Stably free modules over virtually free groups

Let $F_m$ be the free group on $m$ generators and let $G$ be a finite nilpotent group of non square-free order; we show that for each $m\ge 2$ the integral group ring ${\bf Z}[G\times F_m]$ has infinitely many stably free modules of rank 1.Comment: 9 pages. The final publication is available at http://www.springerlink.com doi:10.1007/s00013-012-0432-

Correlated random walks of human embryonic stem cells in vitro

We perform a detailed analysis of the migratory motion of human embryonic stem cells in two-dimensions, both when isolated and in close proximity to another cell, recorded with time-lapse microscopic imaging. We show that isolated cells tend to perform an unusual locally anisotropic walk, moving backwards and forwards along a preferred local direction correlated over a timescale of around 50 min and aligned with the axis of the cell elongation. Increasing elongation of the cell shape is associated with increased instantaneous migration speed. We also show that two cells in close proximity tend to move in the same direction, with the average separation of m or less and the correlation length of around 25 μm, a typical cell diameter. These results can be used as a basis for the mathematical modelling of the formation of clonal hESC colonies

SIMS chemical analysis of extended impacts on the leading and trailing edges of LDEF experiment AO187-2

Numerous 'extended impacts' found in both leading and trailing edge capture cells were successfully analyzed for the chemical composition of projectile residues by secondary ion mass spectrometry (SIMS). Most data were obtained from the trailing edge cells where 45 of 58 impacts were classified as 'probably natural' and the remainder as 'possibly man-made debris.' This is in striking contrast to leading edge cells where 9 of 11 impacts so far measured are definitely classified as orbital debris. Although all the leading edge cells had lost their plastic entrance foils during flight, the rate of foil failure was similar to that of the trailing edge cells, 10 percent of which were recovered intact. Ultraviolet embrittlement is suspected as the major cause of failure on both leading and trailing edges. The major impediment to the accurate determination of projectile chemistry is the fractionation of volatile and refractory elements in the hypervelocity impact and redeposition processes. This effect had been noted in a simulation experiment but is more pronounced in the LDEF capture cells, probably due to the higher average velocities of the space impacts. Surface contamination of the pure Ge surfaces with a substance rich in Si, but also containing Mg and Al, provides an additional problem for the accurate determination of impactor chemistry. The effect is variable, being much larger on surfaces that were exposed to space than in those cells that remained intact. Future work will concentrate on the analyses of more leading edge impacts and the development of new SIMS techniques for the measurement of elemental abundances in extended impacts

A Critical Realist Reflection on the Use of Social Media as Third Space for Rights Education in Early Childhood

The promotion and advancement of Rights Education in Early Childhood ought to be supported through the development of spaces that allow for interdisciplinary discourses among different stakeholders. The project #ChildRightsChat emerged from interactions between the authors to use a digital space to promote the advancement of an interdisciplinary and global discussion about children’s rights. A primary aim was to facilitate adult learning about the protection and promotion of children’s rights in practice. Chats in Twitter, through structured and moderated interactions, were designed to share knowledge and experiences around specific topics. The present paper presents the authors’ reflections, as moderators of #ChildRightsChat, through a critical realist analysis. The findings explore how social media can be understood as a learning environment in ‘third space’, with respect to the nature of interactions that occurred, the context as a learning space, and the voices heard in the chat. The implications of social media to include global perspectives for the advancement of rights-based practice in early childhood education and care are considered

Model Tractor Teaching Tool

A model tractor was developed to teach students about power consumption and wheel slip of farm tractors. The model was selected because of safety and resource issues. Using this model in the lab provided a safe and quiet atmosphere where the principals of power consumption and wheel slip could be demonstrated and learned. The students that participated in the lab appeared to grasp the concepts that were presented