Benefits of a 3D geological model for major tunnelling works : an example from Farringdon, east-central London, UK

In the design of major construction works, the better the ground conditions are known, the more control there is on the assessment of risks for construction, contract and personnel, and ultimately on final costs. Understanding of the ground conditions is usually expressed as a conceptual ground model that is informed by the results of desk study and of dedicated ground investigation. Using the GSI3D software, a 3D geological model (a model composed of attributed solid volumes, rather than of surfaces) can be constructed that exactly honours geologists’ interpretations of the data. The data are used in their true 3D position. The 3D model of faulted Lambeth Group (Palaeogene) strata in the area of the proposed new Crossrail Farringdon underground station, in central London, has several types of benefit. These include allowing optimum use of available ground investigation data, including third party data, with confidence. The model provides an understanding of the local geological structure that had not been possible using other commonly used methods: in particular, it shows the likely distribution of numerous water-bearing coarse deposits and their faulted offsets, which has potentially significant effects on groundwater control. The model can help to focus ground investigation, constrain design and control ris

Charge transfer between Li ions and Li atoms in the 14-1000-eV energy region

By means of a crossed-beam technique, the absolute cross section for charge transfer between lithium ions and lithium atoms has been measured for incident ions energies ranging from 14 to 1000 eV. The lithium ions are produced thermally in a b-eucryptite source and are accelerated and focused into a ribbon beam in a Peirce gun. The total energy spread of the beam is less than 3% at all energies; mass analysis shows that above 1000 degrees C emitter temperature the impurity ions in the beam are below 0.2%. This ion beam traverses a high-density, collimated lithium vapor beam issuing from an oven. A typical density of neutral lithium atoms in the interaction region is 10(13) atoms/cm(8). The slow ions produced in the charge-transfer interaction are collected on a negatively biased cage surrounding the interaction volume of the two beams. The slow-ion charge-transfer completely accounts for the ion-beam attenuation, thus indicating that all scattered beam ions are collected. The vapor-beam density was determined by condensing the vapor on a cold target, dissolving the metallic lithium thus collected, and titrating the resulting solution. The cross section for charge transfer varies from 240 X 10-(16) cm(2) at 14 eV incident ion energy to 880X10-(16) at 1000 eV, and has the expected energy dependence for resonant charge transfer where in cident ion energy E is in eV and Q is in cm(2).Supported by Advanced Research Project Agency, Project Defender. OH wishes to acknowledge support received from the Office of Naval Research though the U.S. Naval Postgraduate School Research Foundation

How does geological heterogeneity control floodplain groundwater dynamics?

Upland floodplains provide an important function in regulating river flows and controlling the coupling of hillslope runoff with rivers. A floodplain in an upland area of the River Tweed catchment, Scotland, was characterised using geophysics, 3D geological mapping, hydrogeological testing and geochemical sampling, and monitored from September 2011 to February 2013 for variations in groundwater levels, river stage, soil moisture and meteorological parameters, including a period of nine months of exceptionally high rainfall. The floodplain contains an unconsolidated, permeable alluvial and glaciofluvial aquifer 8 to 15 m thick, with transmissivity 50 to 1000 m2/d, which is coupled to the hillslope by permeable solifluction deposits. The floodplain aquifer is a significant store of, and conduit for, catchment water. It gains recharge from the river and the adjacent hillslope, transmitting groundwater downstream and acting as a buffer to restrict water flowing from the hillslope from directly entering the river. Floodplain groundwater level fluctuations are driven primarily by changes in river level and the propagation of pressure waves through the floodplain aquifer. There is significant lateral variation in floodplain groundwater response. Most of the floodplain aquifer is hydraulically connected to the river, but groundwater at the edge of the floodplain is strongly controlled by hillslope sub-surface flow. The geological structure and lithology of the hillslope-floodplain transition is an important hydrological control. It can enhance the influence of subsurface hillslope runoff to the floodplain, which has implications for runoff modelling, flood prevention interventions on hillslopes aimed at reducing runoff, and development at floodplain edges. Vertical heterogeneity in hydrological properties within the floodplain aquifer alters hydrological response, causing different depths of the floodplain to respond differently to hillslope and river inputs. These vertical variations need to be better taken into account in floodplain and hillslope-floodplain studies. This research demonstrates the importance of understanding the 3D geology and hydrogeology of floodplains in order to advance catchment research and effective flood management measures

Comparison of BMD changes and bone formation marker levels 3 years after bisphosphonate discontinuation: FLEX and HORIZON-PFT Extension I trials

An ASBMR task force recommends a drug holiday for certain women treated for ≥5 years with oral alendronate or ≥3 years with intravenous zoledronic acid, with reassessment 2-3 years later. It is not known whether changes in BMD or bone turnover markers differ after oral or intravenous therapy. Our goal was to compare changes in BMD and procollagen type I N propeptide, PINP, after oral or intravenous bisphosphonate use. In the Fracture Intervention Trial Long-term Extension (FLEX), women who received a mean 5 years of alendronate were randomized to placebo or continued treatment. In the Health Outcomes and Reduced Incidence with Zoledronic acid Once Yearly-Pivotal Fracture Trial Extension I (HORIZON-PFT E1), women who received 3 years of zoledronic acid were randomized to placebo or continued treatment. We examined the proportion of participants with BMD loss or PINP gain ≥least significant change (LSC), and those whose values exceeded a threshold (T score ≤-2.5 or PINP ≥36.0 ng/mL, a premenopausal median value). After 3 years of placebo, the FLEX group had greater mean total hip BMD decreases (-2.3% versus -1.2% in the HORIZON-PFT E1 group, p < 0.01), and greater rises in PINP (+11.6 ng/mL versus +6.7 ng/mL, p < 0.01). There was a greater proportion of individuals in FLEX with total hip BMD loss and PINP increases that exceeded LSC, and PINP values ≥36.0 ng/mL. In contrast, there were small changes in the proportion of women with femoral neck T scores ≤-2.5 in both groups. In conclusion, 3 years after bisphosphonate discontinuation, a considerable proportion of former alendronate and zoledronic acid users had meaningful declines in total hip BMD and elevations in PINP. Despite a longer treatment course, alendronate may have a more rapid offset of drug effect than zoledronic acid

Hyperfine Magnetic Field Measurement in Heusler Alloys by TDPAC Technique

This work was supported by National Science Foundation Grants PHY 76-84033A01, PHY 78-22774, and Indiana Universit

Mesoscopic interplay of superconductivity and ferromagnetism in ultra-small metallic grains

We review the effects of electron-electron interactions on the ground-state spin and the transport properties of ultra-small chaotic metallic grains. Our studies are based on an effective Hamiltonian that combines a superconducting BCS-like term and a ferromagnetic Stoner-like term. Such terms originate in pairing and spin exchange correlations, respectively. This description is valid in the limit of a large dimensionless Thouless conductance. We present the ground-state phase diagram in the fluctuation-dominated regime where the single-particle mean level spacing is comparable to the bulk BCS pairing gap. This phase diagram contains a regime in which pairing and spin exchange correlations coexist in the ground-state wave function. We discuss the calculation of the tunneling conductance for an almost-isolated grain in the Coulomb-blockade regime, and present measurable signatures of the competition between superconductivity and ferromagnetism in the mesoscopic fluctuations of the conductance.Comment: 6 pages, 3 figures, To be published in the proceedings of the NATO Advance Research Workshop "Recent Advances in Nonlinear Dynamics and Complex System Physics.

Disordered Hubbard Model with Attraction: Coupling Energy of Cooper Pairs in Small Clusters

We generalize the Cooper problem to the case of many interacting particles in the vicinity of the Fermi level in the presence of disorder. On the basis of this approach we study numerically the variation of the pair coupling energy in small clusters as a function of disorder. We show that the Cooper pair energy is strongly enhanced by disorder, which at the same time leads to the localization of pairs.Comment: revtex, 5 pages, 6 figure

Generic Finite Size Enhancement of Pairing in Mesoscopic Fermi Systems

The finite size dependent enhancement of pairing in mesoscopic Fermi systems is studied under the assumption that the BCS approach is valid and that the two body force is size independent. Different systems are investigated such as superconducting metallic grains and films as well atomic nuclei. It is shown that the finite size enhancement of pairing in these systems is in part due to the presence of a surface which accounts quite well for the data of nuclei and explains a good fraction of the enhancement in Al grains.Comment: Updated version 17/02/0

Treatment‐related changes in bone turnover and fracture risk reduction in clinical trials of antiresorptive drugs: proportion of treatment effect explained

Few analyses of antiresorptive (AR) treatment trials relate short‐term changes in bone turnover markers (BTMs) to subsequent fracture reduction seeking to estimate the proportion of treatment effect explained (PTE) by BTMs. Pooling such information would be useful to assess new ARs or novel dosing regimens. In the Foundation for the National Institutes of Health (FNIH) Bone Quality project, we analyzed individual‐level data from up to 62,000 participants enrolled in 12 bisphosphonate (BP) and four selective estrogen receptor modulator (SERM) placebo‐controlled fracture endpoint trials. Using BTM results for two bone formation markers (bone‐specific alkaline phosphatase [bone ALP] and pro‐collagen I N‐propeptide [PINP]) and one bone resorption marker (C‐terminal telopeptide of type I collagen [CTX]) and incident fracture outcome data, we estimated the PTE using two different models. Separate analyses were performed for incident morphometric vertebral, nonvertebral, and hip fractures over 1 to 5 years of follow‐up. For vertebral fracture, the results showed that changes in all three BTMs at 6 months explained a large proportion of the treatment effect of ARs (57 to >100%), but not for and non‐vertebral or hip fracture. We conclude that short‐term AR treatment‐related changes in bone ALP, PINP, and CTX account for a large proportion of the treatment effect for vertebral fracture. Change in BTMs is a useful surrogate marker to study the anti‐fracture efficacy of new AR compounds or novel dosing regiments with approved AR drugs. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research