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Search Results: 1 - 10 of 311447 matches for " Mark J Webber "
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Meta-analysis confirms BCL2 is an independent prognostic marker in breast cancer
Grace M Callagy, Mark J Webber, Paul DP Pharoah, Carlos Caldas
BMC Cancer , 2008, DOI: 10.1186/1471-2407-8-153
Abstract: Reports published in 1994–2006 were selected for the meta-analysis using a search of PubMed. Studies that investigated the role of BCL2 expression by immunohistochemistry with a sample size greater than 100 were included. Seventeen papers reported the results of 18 different series including 5,892 cases with an average median follow-up of 92.1 months.Eight studies investigated DFS unadjusted for other variables in 2,285 cases. The relative hazard estimates ranged from 0.85 – 3.03 with a combined random effects estimate of 1.66 (95%CI 1.25 – 2.22). The effect of BCL2 on DFS adjusted for other prognostic factors was reported in 11 studies and the pooled random effects hazard ratio estimate was 1.58 (95%CI 1.29–1.94). OS was investigated unadjusted for other variables in eight studies incorporating 3,910 cases. The hazard estimates ranged from 0.99–4.31 with a pooled estimate of risk of 1.64 (95%CI 1.36–2.0). OS adjusted for other parameters was evaluated in nine series comprising 3,624 cases and the estimates for these studies ranged from 1.10 to 2.49 with a pooled estimate of 1.37 (95%CI 1.19–1.58).The meta-analysis strongly supports the prognostic role of BCL2 as assessed by immunohistochemistry in breast cancer and shows that this effect is independent of lymph node status, tumour size and tumour grade as well as a range of other biological variables on multi-variate analysis. Large prospective studies are now needed to establish the clinical utility of BCL2 as an independent prognostic marker.Breast cancer is a heterogenous disease whose behaviour is determined by the molecular characteristics of the tumour. In clinical practice, we rely on clinico-pathological features to predict tumour behaviour and patient outcome. These are powerful independent prognosticators [1,2] but are imperfect and represent only crude measures of the biological behaviour of a tumour. The power of these factors can be increased when they are used in combination e.g. the Nottingham Progno
Mismatch Loss Reduction in Photovoltaic Arrays as a Result of Sorting Photovoltaic Modules by Max-Power Parameters
J. Webber,E. Riley
ISRN Renewable Energy , 2013, DOI: 10.1155/2013/327835
Abstract: Variations in photovoltaic (PV) module current-voltage curves result in a power loss in PV arrays often referred to as mismatch loss (MML). As a means of reducing MML, newly fabricated PV modules are sorted to meet a set tolerance for variation in overall maximum power output with respect to a given module’s rated power. Starting with flash test data sets for two different polycrystalline PV modules and a simulated sorting procedure, Monte Carlo techniques were used to generate a large number of artificial PV arrays. The MMLs for each of these arrays were then calculated to assess the sorting procedure’s ability to reduce MML. Overall MMLs were quite small (0.001–0.01%). Sorting by resulted in the most consistent MML reductions. Sorting by yielded insignificant results. Sorting by yielded significant MML reduction in only one of the two PV module data sets. Analysis was conducted to quantify if additional sorting on top of what both manufacturers had already done would make economic sense. Based on high level economic analysis, it appears that additional sorting yields little economic gain; however, this is highly dependent upon manufacturer sorting cost. 1. Introduction Differences in the current-voltage characteristics of photovoltaic (PV) modules give rise to a type of power loss referred to as “electrical mismatch” once modules are connected to networks of series and parallel strings called arrays. The consequence of “mismatch loss” (MML) is that the total power output of a PV array will be less than the sum of the power outputs of the modules as if they were acting independently [1]. This phenomenon has been investigated by a number of authors [1–5] primarily by using one of two methods: the comparison between a PV array’s ideal max-power and the actual max-power computed by progressively synthesizing the curves of modules, series strings, and finally the complete PV array; and MML estimates of PV arrays composed of modules with known or statistically generated characteristics. This second method was made possible by an equation developed by Bucciarelli [1] that estimates MML in PV arrays composed of modules with relatively small variations in their characteristics. Bucciarelli’s [1] model was found to adequately estimate MMLs in 100?kWp arrays by Iannone et al. [2], combining and expanding on the work of Bishop [3] who used random numbers to generate PV modules arranged into arrays, and Chamberlin et al. [4], who estimated small MML values in randomly arranged arrays of four 48?Wp PV modules. After a brief outline of some of the causative
Extraordinary Solar Modulation Effects On Galactic Cosmic Rays Observed By V1 Near The Heliopause
W. R. Webber,J. J. Quenby
Physics , 2014,
Abstract: We discuss two extraordinary increases of cosmic ray intensity observed by Voyager 1 in the last 1.1 AU before heliopause crossing, Aug 2012 at 121.7 AU. The two increases are roughly similar in amplitude and result in a total increase of cosmic ray nuclei around 1 GV of over 50 percent and of 0.01 GV electrons of a factor about 2. During the first increase, the changes in the magnetic, B, field are small. After the first increase, the B field variations and cosmic ray changes become large and during the second increase the B field variations and the cosmic ray changes are correlated to within a day. The intensity variations of H and He nuclei during these time intervals are measured from 0.1 to over 1 GV. The total GCR increse over the two events resemble those expected from a simple force-field 'like' solar modulation model with a modulation potential of about 80MV. This is nearly one third of the total modulation potential of about 250 GV required to produce the modulation of these particles observed at the earth at the 2009 sunspot minimum and adds a new aspect to ideas about heliospheric modulation.
Transient Heliosheath Modulation
J. J. Quenby,W. R. Webber
Physics , 2014, DOI: 10.1093/mnras/stv1482
Abstract: Voyager 1 has explored the solar wind-interstellar medium interaction region between the terminal shock and heliopause following the intensity distribution of galactic cosmic ray protons above 200 MeV energy. Before this component reached the galactic level at 121.7 AU, 4 episodes of rapid intensity change occured similar to the Forbush Decreases found near the sun, rather than the expected result of models related to those describing Long Term Modulation in the inner solar system. Because the mean solar wind flow is both expected and observed to be perpendicular to the radial direction close to the heliopause, explanation is given in terms of transient radial flows related to possible heliopause boundary flapping. It is necessary that radial flows are at the sound speed found for conditions downstream of the teminal shock and that the relevant perpendicular cosmic ray diffusion is controlled by 'slab' field fluctuations accounting for 20 percent or less of the total power in field variance. However, additional radial drift motion related to possible north to south gradients in the magnetic field may allow the inclusion of some diffusion according to 2-D turbulence theory. The required field gradients may arise due to variation in the field carried by the solar plasma deflected away from the solar equatorial plane. Modulation amounting to a total 30 percent drop in galactic intensity requires explanation by a combination of several transient episodes.
The Structure of The Heliopause
J. J. Quenby,W. R. Webber
Physics , 2013, DOI: 10.1093/mnras/stt1813
Abstract: Voyager 1 has explored the solar wind-interstellar medium interaction region between the Terminal Shock and the Heliopause, following the intensity distribution of the shock accelerated anomalous component of cosmic rays in the MeV energy range. The sudden disappearance of this component at 121.7 AU from the sun is discussed in terms of three models for the transition into the interstellar plasma flow. Particles trapped flowing parallel to the boundary may penetrate up to one Larmour radius beyond. If the boundary is stationary, Voyager 1 directly samples this distance. The boundary could flap, depending on Heliosheath pressure changes and Voyager 1 then samples the extent of this motion. Finally, a turbulent boundary layer is considered in which the MeV particle distribution falls off with distance, thus measuring diffusion within the layer.
Managing the Yellow River: Questions of Borders, Boundaries and Access
Michael Webber,Jon Barnett,Brian Finlayson,Mark Wang
Transforming Cultures , 2006,
Abstract: The Yellow River basin is the site of myriad water resource problems. The Yellow River has natural geomorphological characteristics that include seasonally variable flow, very high sediment load, and the capacity to flood with devastating effect. However, people have long sought to harness the water of the Yellow River to their own industrial and agricultural ends, so as to attain the things that they value, like good health, economic growth, and employment. Intensive human use of the basin now poses new managerial problems. The Yellow River’s problems thus now include water scarcity, pollution, and flood risk. In 1997 there were 226 ‘no flow’ days, when the River failed to reach the sea; the dry point started up to 700km inland (Jun 2004). This is not part of the natural flow regime of the Yellow River, which rarely ceased to flow before 1992. The Yellow River is also one of China’s most polluted rivers. While a major breach of the levees has been averted since the People’s Republic was founded in 1949, there is each year significant flooding in the Yellow River basin. The threat of a major levee failure is real and millions of lives and vast sums of capital investment will be lost in such an event, or if one of the many dams along its length fails. In this paper, we characterise the problems of the Yellow River in order to assess the significance of borders, boundaries and access in understanding the management of water. Events and conditions in particular localities have local causes; and in this sense the bounding of regions is significant. Yet borders and boundaries are permeable, permitting causes also to derive from conditions in neighbouring and distant regions. Furthermore, places have causes at a larger scale, such as the nation, since borders, like the regions they bound, are hierarchical and scaled.
Evolution of Water Management in Shanxi and Shaanxi Provinces since the Ming and Qing Dynasties of China
Xiaohong Dang,Michael Webber,Dan Chen,Mark Yaolin Wang
Water , 2013, DOI: 10.3390/w5020643
Abstract: This article examines some of the forms of water management in Shanxi [山西] and Shaanxi [陕西] provinces during the Ming and Qing dynasties. Facing serious water shortages and shrinking state power for water management, the local society in Shanxi and Shaanxi took over water management and gradually formed a local self-government system for the water resources. Depending on water management organizations in which the local gentry were the core power, the water rules were based on natural topographic conditions, historical water practices in the locality, traditional moral-ethical ideas, and even water policies and water laws. This water management system played a positive role in mobilizing the participation of members, preventing opportunistic behavior such as free riding and rent seeking, while decreasing the probability of water conflicts and the costs of litigation. However, this water management system was also subject to endemic corruption because of the lack of effective monitoring from the local government. As similar problems appear to exist in China today, this article analyzes the features of this water management system, and examines the problems that faced those systems so as to provide a warning from history for modern society.
Free perforation of the small intestine in collagenous sprue
Hugh J Freeman, Douglas L Webber
World Journal of Gastroenterology , 2009,
Abstract: A 67-year-old man with celiac disease developed recurrent diarrhea, profound weakness and weight loss, with evidence of marked protein depletion. His clinical course was refractory to a strict gluten-free diet and steroid therapy. Postmortem studies led to definition of unrecognized collagenous sprue that caused ulceration and small intestinal perforation. Although PCR showed identical monoclonal T-cell populations in antemortem duodenal biopsies and postmortem jejunum, careful pathological evaluation demonstrated no frank lymphoma. Rarely, overt or even cryptic T-cell lymphoma may complicate collagenous sprue, however, small intestinal ulcers and perforation may also develop independently. The dramatic findings here may reflect an underlying or early molecular event in the eventual clinical appearance of overt T-cell lymphoma.
HERBVI - a program for simulation of baryon- and lepton- number violating processes
M. J. Gibbs,B. R. Webber
Physics , 1995, DOI: 10.1016/0010-4655(95)00073-O
Abstract: We describe a Monte Carlo event generator for the simulation of baryon- and lepton-number violating processes at supercolliders. The package, {\HERBVI}, is designed as a hard-process generator interfacing to the general hadronic event simulation program {\HW}. In view of the very high multiplicity of gauge bosons expected in such processes, particular attention is paid to the efficient generation of multiparticle phase space. The program also takes account of the expected colour structure of baryon-number violating vertices, which has important implications for the hadronization of the final state.
Libby Amphibole Contamination in Tree Bark Surrounding Historical Vermiculite Processing Facilities  [PDF]
Mohamed I. Elashheb, Terry M. Spear, Julie F. Hart, James S. Webber, Tony J. Ward
Journal of Environmental Protection (JEP) , 2011, DOI: 10.4236/jep.2011.28122
Abstract: Over a 70-year period, a mine near Libby, MT supplied nearly 80% of the world’s vermiculite. Raw vermiculite, which was contaminated with naturally occurring amphibole in veins throughout the deposit, was shipped to processing sites throughout the United States for exfoliation. In this pilot study, tree bark samples were collected near processing facilities in Spokane, WA, Santa Ana, CA, Newark, CA, and Phoenix, AZ in an effort to determine if areas surrounding these facilities are today contaminated with Libby amphibole asbestos (AA). From areas surrounding each of the four historical processing sites, Libby AA was detected in a subset of the bark samples. At the Santa Ana, Newark and Phoenix facilities, actinolite-tremolite and other high Fe Ca-bearing amphibole were also measured from the bark samples. In addition, chrysotile was frequently measured in samples collected from each of the sites. From the results of this pilot study, it is evident that tree bark can serve as reservoirs of asbestos, and indicators of past and current contamination. These data also suggest that areas outside of these historical processing facilities may today have some level of existing contamination resulting from the operation of these facilities.
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