Controlled study of ground-based interferometric radar for rockfall hazard monitoring

The ability to detect small and localized movements of geotechnical facilities is important monitoring and early-warning hazard detection. Current deformation monitoring technology is limited in its ability to both scan massive structures and detect small and localized movements. Ground-based interferometric radar (GBIR) is an emerging remote sensing technology that has the potential to fill this gap in surface deformation monitoring technology. Much of the focus of previous research and application of GBIR has been on monitoring large spatial scale movements, such as mine walls, dams, and earth slopes experiencing deformational movements occurring over hundreds or thousands of square meters. In this study the focus is on evaluating the capabilities of GBIR for detecting and monitoring small movements (mm-scale) occurring over very localized regions (a few m2). Specifically, this study focused on the application of GBIR for detecting and monitoring movements of individual boulders in a massive landscape. The potential long-term application is to use GBIR to detect and monitor precursor movements to rockfall events. Boulders, ranging from 0.5 to 5 meters in approximate facial dimensions, were moved using pry bars and airbag jacks in increments of a few to several mm. Two identical GBIR devices positioned at separate locations scanned a region covering approximately 20,000 m2 after each boulder movement. Ground truth measurements were also performed after each boulder movement. The detectability of the boulder movements was assessed by comparing the distribution of measured phase values from the boulder to (1) phase values measured on the surrounding non-moving portion of the image and (2) phase values measured from the same boulder when it was not moving. The results from the study showed that movements of boulders with dimensions larger than about 2 m were detectable for range offset distances from about 75 to 150 m. Movements as small of 1.7 mm were detected on these larger boulders. Phase values associated with movements of the smaller boulders, with dimensions less than about 2 m, were more difficult to differentiate from the non-moving portions of the image. This study successfully demonstrated the potential of GBIR to fill existing gaps in current displacement and deformation monitoring technology for geotechnical applications

Mitochondrial dysfunction and oxidative stress in patients with chronic kidney disease.

Mitochondria abnormalities in skeletal muscle may contribute to frailty and sarcopenia, commonly present in patients with chronic kidney disease (CKD). Dysfunctional mitochondria are also a major source of oxidative stress and may contribute to cardiovascular disease in CKD We tested the hypothesis that mitochondrial structure and function worsens with the severity of CKD Mitochondrial volume density, mitochondrial DNA (mtDNA) copy number, BNIP3, and PGC1α protein expression were evaluated in skeletal muscle biopsies obtained from 27 subjects (17 controls and 10 with CKD stage 5 on hemodialysis). We also measured mtDNA copy number in peripheral blood mononuclear cells (PBMCs), plasma isofurans, and plasma F2-isoprostanes in 208 subjects divided into three groups: non-CKD (eGFR>60 mL/min), CKD stage 3-4 (eGFR 60-15 mL/min), and CKD stage 5 (on hemodialysis). Muscle biopsies from patients with CKD stage 5 revealed lower mitochondrial volume density, lower mtDNA copy number, and higher BNIP3 content than controls. mtDNA copy number in PBMCs was decreased with increasing severity of CKD: non-CKD (6.48, 95% CI 4.49-8.46), CKD stage 3-4 (3.30, 95% CI 0.85-5.75, P = 0.048 vs. non-CKD), and CKD stage 5 (1.93, 95% CI 0.27-3.59, P = 0.001 vs. non-CKD). Isofurans were higher in patients with CKD stage 5 (median 59.21 pg/mL, IQR 41.76-95.36) compared to patients with non-CKD (median 49.95 pg/mL, IQR 27.88-83.46, P = 0.001), whereas F2-isoprostanes did not differ among groups. Severity of CKD is associated with mitochondrial dysfunction and markers of oxidative stress. Mitochondrial abnormalities, which are common in skeletal muscle from patients with CKD stage 5, may explain the muscle dysfunction associated with frailty and sarcopenia in CKD Further studies are required to evaluate mitochondrial function in vivo in patients with different CKD stages

Precision determination of absolute neutron flux

A technique for establishing the total neutron rate of a highly-collimated monochromatic cold neutron beam was demonstrated using a method of an alpha-gamma counter. The method involves only the counting of measured rates and is independent of neutron cross sections, decay chain branching ratios, and neutron beam energy. For the measurement, a target of 10B-enriched boron carbide totally absorbed the neutrons in a monochromatic beam, and the rate of absorbed neutrons was determined by counting 478keV gamma rays from neutron capture on 10B with calibrated high-purity germanium detectors. A second measurement based on Bragg diffraction from a perfect silicon crystal was performed to determine the mean de Broglie wavelength of the beam to a precision of 0.024 %. With these measurements, the detection efficiency of a neutron monitor based on neutron absorption on 6Li was determined to an overall uncertainty of 0.058 %. We discuss the principle of the alpha-gamma method and present details of how the measurement was performed including the systematic effects. We also describe how this method may be used for applications in neutron dosimetry and metrology, fundamental neutron physics, and neutron cross section measurements.Comment: 44 page

Grout and vitrification formula development for immobilization of hazardous radioactive tank sludges at ORNL

Stabilization/solidification (S/S) has been identified as the preferred treatment option for hazardous radioactive sludges, and currently grouting and vitrification are considered the leading candidate S/S technologies. Consequently, a project was initiated at Oak Ridge National Laboratory (ORNL) to define composition envelopes, or operating windows, for acceptable grout and glass formulations containing Melton Valley Storage Tank (MVST) sludges. The resulting data are intended to be used as guidance for the eventual treatment of the MVST sludges by the government and/or private sector. Wastewater at ORNL is collected, evaporated, and stored in the MVSTs pending treatment for disposal. The waste separates into two phases: sludge and supernate. The sludges in the tank bottoms have been accumulating for several years and contain a high amount of radioactivity, with some classified as transuranic (TRU) sludges. The available total constituent analysis for the MVST sludge indicates that the Resource and Conservation Recovery Act (RCRA) metal concentrations are high enough to be potentially RCRA hazardous; therefore, these sludges have the potential to be designated as mixed TRU waste. S/S treatment must be performed to remove free liquids and reduce the leach rate of RCRA metals. This paper focuses on initial results for the development of the operating window for vitrification. However, sufficient data on grouting are presented to allow a comparison of the two options

Waste vitrification: prediction of acceptable compositions in a lime-soda-silica glass-forming system

A model is presented based upon calculated bridging oxygens which allows the prediction of the region of acceptable glass compositions for a lime-soda-silica glass-forming system containing mixed waste. The model can be used to guide glass formulation studies (e.g., treatability studies) or assess the applicability of vitrification to candidate waste streams

Siderastrea siderea Spawning and Oocyte Resorption at High Latitude

At high latitudes (\u3e25°), sexual reproduction and the maintenance of coral populations can be impaired by marginal environmental conditions. However, little is known about sexual reproduction of many coral species at high latitude on the northern-most extension of the Florida Reef Tract. This study aimed to histologically characterize the reproductive ecology of Siderastrea siderea, near Fort Lauderdale, Florida (26°N). Tissue samples of S. siderea were collected semi-monthly to multiweekly from August to November in 2007 and 2008. Spawning was inferred from gametogenesis and oocyte resorption was observed in detail. Environmental variables including temperature and lunar cycle were examined for relationship with potential spawning times. Based on the histological evidence, we infer that spawning likely occurred primarily in October. Gametogenesis in this species is likely mediated by seasonal temperature variation, whereas lunar cycle could act as finer scale environmental cue for coordination of spawning. Our findings highlight that S. siderea spawning occurs later in the year compared to other populations of this species throughout the Caribbean and to other coral species near Fort Lauderdale. For the first time, oocyte resorption stages are described and constitute a baseline for future projects that aim to understand this process in corals

Changes in soil carbon sequestration in <i>Pinus massoniana</i> forests along an urban-to-rural gradient of southern China

Urbanization is accelerating globally, causing a variety of environmental changes such as increases in air temperature, precipitation, atmospheric CO₂, and nitrogen (N) deposition. However, the effects of these changes on forest soil carbon (C) sequestration remain largely unclear. Here, we used urban-to-rural environmental gradients in Guangdong Province, southern China, to address the potential effects of these environmental changes on soil C sequestration in <i>Pinus massoniana</i> forests. In contrast to our expectations and earlier observations, soil C content in urban sites was significantly lower than that in suburban and rural sites. Lower soil C pools in urban sites were correlated with a significant decrease in fine root biomass and a potential increase in soil organic C decomposition. Variation of soil C pools was also a function of change in soil C fractions. Heavy fraction C content in urban sites was significantly lower than that in suburban and rural sites. By contrast, light fraction C content did not vary significantly along the urban-to-rural gradient. Our results suggest that urbanization-induced environmental changes may have a negative effect on forest soil C in the studied region

Evaluation of a spring-powered captive bolt gun for killing kangaroo pouch young

Context: During commercial harvesting or non-commercial kangaroo culling programs, dependent young of shot females are required to be euthanased to prevent suffering and because they would be unlikely to survive. However, the current method for killing pouch young, namely a single, forceful blow to the base of the skull, is applied inconsistently by operators and perceived by the public to be inhumane. Aims: To determine whether an alternative method for killing pouch young, namely a spring-operated captive bolt gun, is effective at causing insensibility in kangaroo pouch young. Methods: Trials of spring-operated captive bolt guns were conducted first on the heads of 15 dead kangaroo young and then on 21 live pouch young during commercial harvesting. We assessed the effectiveness at causing insensibility in live animals and damage caused to specific brain areas. We also measured depth of bolt penetration and skull thickness. Performance characteristics (e.g. bolt velocity) of two types of spring-operated guns were also measured and compared with cartridge-powered devices. Key results: When tested on the heads of dead animals, the spring-operated captive bolt gun consistently produced a large entrance cavity and a well defined wound tract, which extended into the cerebrum, almost extending the full thickness of the brain, including the brainstem. When tested on live pouch young, the captive bolt gun caused immediate insensibility in only 13 of 21 animals. This 62% success rate is significantly below the 95% minimum acceptable threshold for captive bolt devices in domestic animal abattoirs. Failure to stun was related to bolt placement, but other factors such as bolt velocity, bolt diameter and skull properties such as thickness and hardness might have also contributed. Spring-operated captive bolt guns delivered 20 times less kinetic energy than did cartridge-powered devices. Conclusions: Spring-operated captive bolt guns cannot be recommended as an acceptable or humane method for stunning or killing kangaroo pouch young. Implications: Captive bolt guns have potential as a practical alternative to blunt head trauma for effective euthanasia and reducing animal (and observer) distress. However, operators must continue to use the existing prescribed killing methods until cartridge-powered captive bolt guns have been trialled as an alternative bolt propelling method. Additional keywords: animal welfare, blunt trauma, culling, euthanasia, humaneness, kangaroo harvesting

Global assessment of nitrogen deposition effects on terrestrial plant diversity : a synthesis

Atmospheric nitrogen (N) deposition is it recognized threat to plant diversity ill temperate and northern parts of Europe and North America. This paper assesses evidence from field experiments for N deposition effects and thresholds for terrestrial plant diversity protection across a latitudinal range of main categories of ecosystems. from arctic and boreal systems to tropical forests. Current thinking on the mechanisms of N deposition effects on plant diversity, the global distribution of G200 ecoregions, and current and future (2030) estimates of atmospheric N-deposition rates are then used to identify the risks to plant diversity in all major ecosystem types now and in the future. This synthesis paper clearly shows that N accumulation is the main driver of changes to species composition across the whole range of different ecosystem types by driving the competitive interactions that lead to composition change and/or making conditions unfavorable for some species. Other effects such its direct toxicity of nitrogen gases and aerosols long-term negative effects of increased ammonium and ammonia availability, soil-mediated effects of acidification, and secondary stress and disturbance are more ecosystem, and site-specific and often play a supporting role. N deposition effects in mediterranean ecosystems have now been identified, leading to a first estimate of an effect threshold. Importantly, ecosystems thought of as not N limited, such as tropical and subtropical systems, may be more vulnerable in the regeneration phase. in situations where heterogeneity in N availability is reduced by atmospheric N deposition, on sandy soils, or in montane areas. Critical loads are effect thresholds for N deposition. and the critical load concept has helped European governments make progress toward reducing N loads on sensitive ecosystems. More needs to be done in Europe and North America. especially for the more sensitive ecosystem types. including several ecosystems of high conservation importance. The results of this assessment Show that the Vulnerable regions outside Europe and North America which have not received enough attention are ecoregions in eastern and Southern Asia (China, India), an important part of the mediterranean ecoregion (California, southern Europe). and in the coming decades several subtropical and tropical parts of Latin America and Africa. Reductions in plant diversity by increased atmospheric N deposition may be more widespread than first thought, and more targeted Studies are required in low background areas, especially in the G200 ecoregions