Analyzing large-scale conservation interventions with Bayesian hierarchical models: a case study of supplementing threatened Pacific salmon.

Myriad human activities increasingly threaten the existence of many species. A variety of conservation interventions such as habitat restoration, protected areas, and captive breeding have been used to prevent extinctions. Evaluating the effectiveness of these interventions requires appropriate statistical methods, given the quantity and quality of available data. Historically, analysis of variance has been used with some form of predetermined before-after control-impact design to estimate the effects of large-scale experiments or conservation interventions. However, ad hoc retrospective study designs or the presence of random effects at multiple scales may preclude the use of these tools. We evaluated the effects of a large-scale supplementation program on the density of adult Chinook salmon Oncorhynchus tshawytscha from the Snake River basin in the northwestern United States currently listed under the U.S. Endangered Species Act. We analyzed 43 years of data from 22 populations, accounting for random effects across time and space using a form of Bayesian hierarchical time-series model common in analyses of financial markets. We found that varying degrees of supplementation over a period of 25 years increased the density of natural-origin adults, on average, by 0-8% relative to nonsupplementation years. Thirty-nine of the 43 year effects were at least two times larger in magnitude than the mean supplementation effect, suggesting common environmental variables play a more important role in driving interannual variability in adult density. Additional residual variation in density varied considerably across the region, but there was no systematic difference between supplemented and reference populations. Our results demonstrate the power of hierarchical Bayesian models to detect the diffuse effects of management interventions and to quantitatively describe the variability of intervention success. Nevertheless, our study could not address whether ecological factors (e.g., competition) were more important than genetic considerations (e.g., inbreeding depression) in determining the response to supplementation

Development of a new laser Doppler velocimeter for the Ames High Reynolds Channel No. 2

A new two-channel laser Doppler velocimeter developed for the Ames High Reynolds Channel No. 2 is described. Design features required for the satisfactory operation of the optical system in the channel environment are discussed. Fiber optics are used to transmit the megahertz Doppler signal to the photodetectors located outside the channel pressure vessel, and provision is made to isolate the optical system from pressure and thermal strain effects. Computer-controlled scanning mirrors are used to position the laser beams in the channel flow. Techniques used to seed the flow with 0.5-micron-diam polystyrene spheres avoiding deposition on the test-section windows and porous boundary-layer removal panels are described. Preliminary results are presented with a discussion of several of the factors affecting accuracy

Antibacterial Properties of a Tri-Sodium Citrate Modified Glass Polyalkenoate Cement

Primary deep infection following joint replacement surgery accounts for 7% of all revisions. Glass polyalkenoate cements (GPCs) have previously been shown to exhibit antibacterial properties. The present study had two objectives. The first was to determine if addition of tri-sodium citrate (TSC) to the powder phase of an Al-free GPC (0.04 SrO-0.12 CaO-0.36 ZnO-0.48 SiO2, by mole fraction) enhanced the resultant cement\u27s antibacterial properties against three strains of bacteria that are commonly found in periprosthetic sites following total joint replacements (TJRs); namely, E. coli, B. fragilis, and S. epidermidis. Four cement sets were prepared, which contained 0 wt% TSC (control), 5 wt% TSC, 10 wt% TSC, and 15 wt% TSC. All the TSC-modified cements were found to exhibit large inhibition zones against all the bacterial strains, especially the cement containing 15 wt% TSC against E. coli. The antibacterial properties of the TSC containing GPCs are attributed to the release of Zn and Na ions from the cements and the presence of the TSC. The second objective was to investigate if, when a modified GPC is embedded in a bovine bone model, ionic transfer occurs. It was found that Zn ions migrated from the cement to the surrounding bone, particularly at the cement-bone interface. This is a desirable outcome as Zn ions are known to play a vital role in both bone metabolism and the regeneration of healthy bone. The present results point to the potential clinical benefits of using TSC-modified GPCs in TJRs. © 2009 Wiley Periodicals, Inc

Pyrolysis of auto shredder residue : Experiments with a laboratory screw kiln reactor

The pyrolysis of automobile shredder residue (ASR) has been studied using a laboratory scale screw kiln reactor with a feed rate of about 100 g h\u207b\ub9. Pyrolysis at temperatures between 500 and 750\ub0C resulted in the production of gas, liquid and solid fractions with hydrocarbon yields of the organic fraction present in the feed increasing from 60\u201385% with increasing pyrolysis temperature. While the hydrocarbon pyrolysis product yield increased with pyrolysis temperature, the yield of the oil fraction was higher at the lower pyrolysis temperatures. The composition of the pyrolysis oil also changed with pyrolysis temperature, containing larger quantities of aliphatic compounds at the lower temperatures than at higher temperatures where aromatics were the major compounds. Many of the liquid pyrolysis products have been identified including polycyclic aromatic hydrocarbons as well as organo nitrogen, sulphur and chlorine compounds. The data obtained have been compared with that obtained from a process using short pyrolysis residence times.Peer reviewed: YesNRC publication: Ye

Modeling Global Warming Scenarios in Greenback Cutthroat Trout (\u3cem\u3eOncorhynchus Clarki Stomias\u3c/em\u3e) Streams: Implications for Species Recovery

Changes in global climate may exacerbate other anthropogenic stressors, accelerating the decline in distribution and abundance of rare species throughout the world. We examined the potential effects of a warming climate on the greenback cutthroat trout (Oncorhynchus clarki stomias), a resident salmonid that inhabits headwater streams of the central Rocky Mountains. Greenbacks are outcompeted at lower elevations by nonnative species of trout and currently are restricted to upper-elevation habitats where barriers to upstream migration by nonnatives are or have been established. We used likelihood-based techniques and information theoretics to select models predicting stream temperature changes for 10 streams where greenback cutthroat trout have been translocated. These models showed high variability among responses by different streams, indicating the usefulness of a stream-specific approach. We used these models to project changes in stream temperatures based on 2°C and 4°C warming of average air temperatures. In these warming scenarios, spawning is predicted to begin from 2 to 3.3 weeks earlier than would be expected under baseline conditions. Of the 10 streams used in this assessment, 5 currently have less than a 50% chance of translocation success. Warming increased the probability of translocation success in these 5 streams by 11.2% and 21.8% in the 2 scenarios, respectively. Assuming barriers to upstream migration by nonnative competitors maintain their integrity, we conclude that an overall habitat improvement results because greenbacks have been restricted through competition with nonnatives to suboptimal habitats, which are generally too cold to be highly productive

Employment relations and social stratification in contemporary urban China: does Goldthorpe’s class theory still work?

Goldthorpe’s class theory suggests that social class arises from employment relations in industrialised societies. This article assesses whether class in urban China can be approached from the same perspective by addressing three issues: 1) whether employment relations can capture China’s class structure, 2) how differently class is shaped by occupational structure in China, and 3) how useful class is to help us understand income inequality. Based on a recent Chinese social survey, the analysis finds three clusters of Chinese employees that fit into the ‘service’, ‘intermediate’ and ‘labour contract’ class typologies suggested by Goldthorpe’s class theory. Also, there is evidence that class links to occupational structures in a similar way between Chinese and Western societies. Finally class, when directly measured from employment relations, displays a reasonable degree of explanatory power for inter-class income inequality whereas the Goldthorpe class classification fails to differentiate between intermediate and labour class positions

Activation of AMPK by bitter melon triterpenoids involves CaMKKβ

We recently showed that bitter melon-derived triterpenoids (BMTs) activate AMPK and increase GLUT4 translocation to the plasma membrane in vitro, and improve glucose disposal in insulin resistant models in vivo. Here we interrogated the mechanism by which these novel compounds activate AMPK, a leading anti-diabetic drug target. BMTs did not activate AMPK directly in an allosteric manner as AMP or the Abbott compound (A-769662) does, nor did they activate AMPK by inhibiting cellular respiration like many commonly used anti-diabetic medications. BMTs increased AMPK activity in both L6 myotubes and LKB1-deficient HeLa cells by 20-35%. Incubation with the CaMKKß inhibitor, STO-609, completely attenuated this effect suggesting a key role for CaMKKß in this activation. Incubation of L6 myotubes with the calcium chelator EGTA-AM did not alter this activation suggesting that the BMT-dependent activation was Ca2+-independent. We therefore propose that CaMKKß is a key upstream kinase for BMT-induced activation of AMPK

Analysis of the rotation period of asteroids (1865) Cerberus, (2100) Ra-Shalom, and (3103) Eger - search for the YORP effect

The spin state of small asteroids can change on a long timescale by the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, the net torque that arises from anisotropically scattered sunlight and proper thermal radiation from an irregularly-shaped asteroid. The secular change in the rotation period caused by the YORP effect can be detected by analysis of asteroid photometric lightcurves. We analyzed photometric lightcurves of near-Earth asteroids (1865) Cerberus, (2100) Ra-Shalom, and (3103) Eger with the aim to detect possible deviations from the constant rotation caused by the YORP effect. We carried out new photometric observations of the three asteroids, combined the new lightcurves with archived data, and used the lightcurve inversion method to model the asteroid shape, pole direction, and rotation rate. The YORP effect was modeled as a linear change in the rotation rate in time d\omega /dt. Values of d\omega/ dt derived from observations were compared with the values predicted by theory. We derived physical models for all three asteroids. We had to model Eger as a nonconvex body because the convex model failed to fit the lightcurves observed at high phase angles. We probably detected the acceleration of the rotation rate of Eger d\omega / dt = (1.4 +/- 0.6) x 10^{-8} rad/d (3\sigma error), which corresponds to a decrease in the rotation period by 4.2 ms/yr. The photometry of Cerberus and Ra-Shalom was consistent with a constant-period model, and no secular change in the spin rate was detected. We could only constrain maximum values of |d\omega / dt| < 8 x 10^{-9} rad/d for Cerberus, and |d\omega / dt| < 3 x 10^{-8} rad/d for Ra-Shalom

Thermal analysis of some environmentally degradable polymers

The thermal characteristics of a series of degradable polymers have been investigated using thermogravimetry and differential scanning calorimetry. While the results of the thermogravimetry experiments suggest that the thermal stability of the polymers should not pose any problems at the temperatures that can be expected in a commercial composting process (60\ub0C), phase changes associated with some of the polymers investigated may cause problems in the interpretation of data from composting degradation studies. Several biodegradable polymers were observed to have melt transitions at temperatures similar to those found in a compositing environment. Consequently, under the controlled composting conditions used to evaluate biodegradable polymers, degradation of a polymer may be inferred, while actually the polymer has merely undergone a phase change.Peer reviewed: YesNRC publication: Ye

Two approaches to testing general relativity in the strong-field regime

Observations of compact objects in the electromagnetic spectrum and the detection of gravitational waves from them can lead to quantitative tests of the theory of general relativity in the strong-field regime following two very different approaches. In the first approach, the general relativistic field equations are modified at a fundamental level and the magnitudes of the potential deviations are constrained by comparison with observations. In the second approach, the exterior spacetimes of compact objects are parametrized in a phenomenological way, the various parameters are measured observationally, and the results are finally compared against the general relativistic predictions. In this article, I discuss the current status of both approaches, focusing on the lessons learned from a large number of recent investigations.Comment: To appear in the proceedings of the conference New Developments in Gravit