DETERMINATION OF ENERGY ABSORPTION CAPABILITIES OF LARGE SCALE SHOTCRETE PANELS

The Western Australian School of Mines (WASM) has developed a facility for the static testing of full scale ground support elements. The test facility consists of several stiff steel frames used to support the sample and a screw feed jack is used to load the sample. A large scale punch test method has been developed to evaluate various shotcrete mix designs at different curing times. The shotcrete is sprayed on to a sandstone substrate containing an isolated disc that is centrally located. The test sample is placed on to the sample frame and restrained on all sides. The disc is displaced at a constant rate by the screw feed jack which in turn loads the sample. Instruments measure the displacement and the load being applied to the sample through the loading disc. The test method has been used to compare the force – displacement properties of different mix designs and reinforcing materials including plastic fibres, steel fibres and mesh. The force – displacement properties have been used to determine the energy absorbing capability of fibrecrete systems

NON-LINEAR, ELASTIC - PLASTIC RESPONSE OF STEEL FIBRE REINFORCED SHOTCRETE TO UNIAXIAL AND TRIAXIAL COMPRESSION TESTING

Understanding the complete stress-strain behavior of shotcrete is extremely important in ground support design; especially in cases where large deformations are expected such as around mine excavations at great depth. The application of non-linear numerical modeling to mining industry problems has increased in recent years. More realistic stress-strain response and failure criteria in complex plasticity models are also being used in the design of the larger, deeper mines. One of the factors to improve the reliability of numerical modeling is to properly define geotechnical parameters for both the rock mass and shotcrete surface support. Uniaxial and triaxial compression tests on steel fibre reinforced shotcrete (SFRS) have been used to quantify elastic-plastic response behaviour for both the peak and post-peak regions. The laboratory tests were conducted with a servo-controlled testing machine to obtain complete stress-strain curves. The test results include unconfined and triaxial compressive strength, shear strength and tensile strength together with the elastic and plastic mechanical properties of SFRS. A method is also suggested for obtaining the plasticity parameters for non-linear modeling of SFRS

Utah’s Watershed Restoration Initiative: Restoring Watersheds at a Landscape Scale

Abstract: The Utah Watershed Restoration Initiative (WRI) is a partnership-based program, administered by the Utah Department of Natural Resources, which seeks to improve the functional capacity of high priority watersheds throughout the state. Since its inception in 2006, the WRI partnership has completed nearly 1,500 projects to restore and rehabilitate over 526,091 ha in Utah watersheds. The WRI program is unique to the west, in that it transcends jurisdictional boundaries, and local, state, and federal management authority to focus finite resources on completing high priority conservation projects. We surveyed selected WRI selected participants in 2015 to determine what factors they believed most contributed to the overall success of the program. Survey respondents attributed the success of the WRI program to: 1) engaged leadership at multiple levels, 2) a bottom-up hierarchy, 3) a history of collaboration, 4) practice partnerships, 5) a science-based approach, 6) operating at a meaningful spatial scale, 7) being solution minded, not problem focused, and 8) unselfish sharing of resources. In this paper we discuss these success factors and provide recommendations to those desiring to implement voluntary incentive-based landscape conservation strategies

Inflammation in benign prostate tissue and prostate cancer in the finasteride arm of the Prostate Cancer Prevention Trial

BACKGROUND: A previous analysis of the placebo arm of the Prostate Cancer Prevention Trial (PCPT) reported 82% overall prevalence of intraprostatic inflammation and identified a link between inflammation and higher-grade prostate cancer and serum PSA. Here we studied these associations in the PCPT finasteride arm. METHODS: Prostate cancer cases (N=197) detected either on a clinically indicated biopsy or on protocol-directed end-of-study biopsy, and frequency-matched controls (N=248) with no cancer on an end-of-study biopsy were sampled from the finasteride arm. Inflammation in benign prostate tissue was visually assessed using digital images of H&E stained sections. Logistic regression was used for statistical analysis. RESULTS: In the finasteride arm, 91.6% of prostate cancer cases and 92.4% of controls had at least one biopsy core with inflammation in benign areas; p < 0.001 for difference compared to placebo arm. Overall, the odds of prostate cancer did not differ by prevalence (OR=0.90, 95% CI 0.44-1.84) or extent (P-trend=0.68) of inflammation. Inflammation was not associated with higher-grade disease (prevalence: OR=1.07, 95% CI 0.43-2.69). Furthermore, mean PSA concentration did not differ by the prevalence or extent of inflammationin either cases or controls. CONCLUSION: The prevalence of intraprostatic inflammation was higher in the finasteride than placebo arm of the PCPT, with no association with higher-grade prostate cancer. IMPACT: Finasteride may attenuate the association between inflammation and higher-grade prostate cancer. Moreover, the missing link between intraprostatic inflammation and PSA suggests that finasteride may reduce inflammation-associated PSA elevation

Transmission potential of Rift Valley fever virus over the course of the 2010 epidemic in South Africa.

A Rift Valley fever (RVF) epidemic affecting animals on domestic livestock farms was reported in South Africa during January-August 2010. The first cases occurred after heavy rainfall, and the virus subsequently spread countrywide. To determine the possible effect of environmental conditions and vaccination on RVF virus transmissibility, we estimated the effective reproduction number (Re) for the virus over the course of the epidemic by extending the Wallinga and Teunis algorithm with spatial information. Re reached its highest value in mid-February and fell below unity around mid-March, when vaccination coverage was 7.5%-45.7% and vector-suitable environmental conditions were maintained. The epidemic fade-out likely resulted first from the immunization of animals following natural infection or vaccination. The decline in vector-suitable environmental conditions from April onwards and further vaccination helped maintain Re below unity. Increased availability of vaccine use data would enable evaluation of the effect of RVF vaccination campaigns

Simultaneous assessment of regional distributions of atrophy across the neuraxis in MS patients

BACKGROUND: The ability to assess brain and cord atrophy simultaneously would improve the efficiency of MRI to track disease evolution. OBJECTIVE: To test a promising tool to simultaneously map the regional distribution of atrophy in multiple sclerosis (MS) patients across the brain and cord. METHODS: Voxel-based morphometry combined with a statistical parametric mapping probabilistic brain-spinal cord (SPM-BSC) template was applied to standard T1-weighted magnetic resonance imaging (MRI) scans covering the brain and cervical cord from 37 MS patients and 20 healthy controls (HC). We also measured the cord area at C2-C3 with a semi-automatic segmentation method using (i) the same T1-weighted acquisitions used for the new voxel-based analysis and (ii) dedicated spinal cord phase sensitive inversion recovery (PSIR) acquisitions. Cervical cord findings derived from the three approaches were compared to each other and the goodness to fit to clinical scores was assessed by regression analyses. RESULTS: The SPM-BSC approach revealed a severity-dependent pattern of atrophy across the cervical cord and thalamus in MS patients when compared to HCs. The magnitude of cord atrophy was confirmed by the semi-automatic extraction approach at C2-C3 using both standard brain T1-weighted and advanced cord dedicated acquisitions. Associations between atrophy of cord and thalamus with disability and cognition were demonstrated. CONCLUSION: Atrophy in the brain and cervical cord of MS patients can be identified simultaneously and rapidly at the voxel-level. The SPM-BSC approach yields similar results as available standard processing tools with the added advantage of performing the analysis simultaneously and faster

Killing Tensors and Conformal Killing Tensors from Conformal Killing Vectors

Koutras has proposed some methods to construct reducible proper conformal Killing tensors and Killing tensors (which are, in general, irreducible) when a pair of orthogonal conformal Killing vectors exist in a given space. We give the completely general result demonstrating that this severe restriction of orthogonality is unnecessary. In addition we correct and extend some results concerning Killing tensors constructed from a single conformal Killing vector. A number of examples demonstrate how it is possible to construct a much larger class of reducible proper conformal Killing tensors and Killing tensors than permitted by the Koutras algorithms. In particular, by showing that all conformal Killing tensors are reducible in conformally flat spaces, we have a method of constructing all conformal Killing tensors (including all the Killing tensors which will in general be irreducible) of conformally flat spaces using their conformal Killing vectors.Comment: 18 pages References added. Comments and reference to 2-dim case. Typos correcte

Pooled Versus Individualized Load–Velocity Profiling in the Free-Weight Back Squat and Power Clean

Purpose: This study compared pooled against individualized load–velocity profiles (LVPs) in the free-weight back squat and power clean. Methods: A total of 10 competitive weightlifters completed baseline 1-repetition maximum assessments in the back squat and power clean. Three incremental LVPs were completed, separated by 48 to 72 hours. Mean and peak velocity were measured via a linear-position transducer (GymAware). Linear and nonlinear (second-order polynomial) regression models were applied to all pooled and individualized LVP data. A combination of coefficient of variation (CV), intraclass correlation coefficient, typical error of measurement, and limits of agreement assessed between-subject variability and within-subject reliability. Acceptable reliability was defined a priori as intraclass correlation coefficient > .7 and CV < 10%. Results: Very high to practically perfect inverse relationships were evident in the back squat (r = .83–.96) and power clean (r = .83–.89) for both regression models; however, stronger correlations were observed in the individualized LVPs for both exercises (r = .85–.99). Between-subject variability was moderate to large across all relative loads in the back squat (CV = 8.2%–27.8%) but smaller in the power clean (CV = 4.6%–8.5%). The power clean met our criteria for acceptable reliability across all relative loads; however, the back squat revealed large CVs in loads ≥90% of 1-repetition maximum (13.1%–20.5%). Conclusions: Evidently, load– velocity characteristics are highly individualized, with acceptable levels of reliability observed in the power clean but not in the back squat (≥90% of 1-repetition maximum). If practitioners want to adopt load–velocity profiling as part of their testing and monitoring procedures, an individualized LVP should be utilized over pooled LVPs

The SLAC high‐density 3He target polarized by spin‐exchange optical plumbing

A new high‐density 3He target polarized by spin exchange with optically pumped rubidium vapor has recently been used at the Stanford Linear Accelerator in an experiment to measure the longitudinal spin‐dependent structure function of the neutron. The 3He target operated at a density of 2.3×1020 atoms/cm3 in a 30 cm long scattering region with polarizations between 30% and 40% measured with NMR techniques. Target cells with several day spin‐relaxation times were developed in order to achieve these polarizations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87509/2/244_1.pd