Top Quark Measurements at the Fermilab Tevatron

The top quark, discovered at the Tevatron in 1995, is a very interesting particle. Precise measurement of the top properties using large data samples will allow stringent tests of the Standard Model and offer a unique window on new physics. In this report will be reviewed the status of the current knowledge of the top quark as provided by the Run I results of the CDF and D0 experiment. A first look at various preliminary measurements obtained with data collected during Run II will be also presented.Comment: 10 pages, 14 figures Proceeding of Lepton-Photon 2003, Fermilab Batavia (IL), August 200

Attitudes toward Teaching English in Lebanon: An Exercise in Critical Applied Linguistics

Critical Applied Linguistics (CALx) is both a means of examining the status quo governing the teaching and learning of languages and an opportunity to change or transform existing assumptions and practices. Within the multilingual context of Lebanon, my initial assumption was that English foreign language teachers have not explicitly scrutinized their attitudes to the language they teach or its impact on Arabic (L1). Teacher education and professional development have also not appeared to provide an opportunity to facilitate such a discussion. As such, my study based itself upon the assumption that current teacher education and training have established and reaffirmed mainstream attitudes to the teaching and learning of foreign languages in Lebanon. In order to examine my critical position, my study involved two main phases. Using action research with a mixed methods approach to data collection, the first phase included a survey of 62 English language teachers from different contexts: primary, middle, and high school, in addition to tertiary education. The purpose of this survey was to determine whether teacher attitudes would be mainstream or explicitly critical. In the second phase, I created an intervention in the form of a ‘reflexive practice model’, wherein nine in-service English language teachers, from different contexts as well, would meet to discuss relevant critical themes in the hopes of creating a platform for dialogic inquiry and transformation. Following the model set by Kumaravadivelu (2012), these sessions would value both professional and personal knowledge as participants negotiated their espoused attitudes, with emphasis on the local, ‘lived’, experience. The results of my research showed that teachers, in general, had some mainstream attitudes to the teaching of English, especially the need for early exposure to a foreign language, maximum exposure through English as a medium of instruction, and the monolingual fallacy. They also commonly taught English without reflecting upon any power dynamics or hegemony involved. While most participants agreed that the Arabic language might be suffering because of these practices, they did not believe they had any active role to play in order to preserve L1. However, they were also critical of certain pedagogical practices, especially related to teaching resources and policies that left them feeling powerless and passive. They also mostly believed that their professional development opportunities were insufficient and involved sporadic, expert-led, sessions that were not immediately relevant to their context. From an action research perspective, the ‘reflexive practice model’ was successful as it allowed participants to discuss their assumptions and identity as a whole, creating some immediate change in attitudes and practice, in addition to a feeling of empowerment and hope in a better future. Participants also concluded that such communities of practice would provide in-service teachers with a voice that they could later amplify both within their institutions and beyond, through publishing their findings and participating in conferences in Lebanon that included both ‘experts’ and the practicing teachers. Thus, this ‘reflexive practice model’ can provide an opportunity for continuing – and critical - professional development that also allows participants from different institutions to support one another as they reflect upon their identity and practice

Comments on "Wall-plug (AC) power consumption of a very high energy e+/e- storage ring collider" by Marc Ross

The paper arXiv:1308.0735 questions some of the technical assumptions made by the TLEP Steering Group when estimating in arXiv:1305.6498 the power requirement for the very high energy e+e- storage ring collider TLEP. We show that our assumptions are based solidly on CERN experience with LEP and the LHC, as well accelerators elsewhere, and confirm our earlier baseline estimate of the TLEP power consumption.Comment: 6 page

Behaviour of parallel girders stabilised with u-frames

Lateral torsional buckling is a key factor in the design of steel girders. Stability can be enhanced by cross‐bracing, reducing the effective length and thus increasing the ultimate capacity. U‐frames are an option often used to brace the girders, when designing through type of bridges and where overhead bracing is not practical. This paper investigates the effect of the U‐frame spacing on the stability of the parallel girders. Eigenvalue buckling analysis was undertaken with four different spacings of the U‐frames. Results were extracted from finite element analysis, interpreted and conclusions drawn

Unifying gauge couplings at the string scale

Using the current precision electroweak data, we look for the minimal particle content which is necessary to add to the standard model in order to have a complete unification of gauge couplings and gravity at the weakly coupled heterotic string scale. We find that the addition of a vector-like fermion at an intermediate scale and a non-standard hypercharge normalization are in general sufficient to achieve this goal at two-loop level. Requiring the extra matter scale to be below the TeV scale, it is found that the addition of three vector-like fermion doublets with a mass around 700 GeV yields a perfect string-scale unification, provided that the affine levels are $(k_Y, k_2 ,k_3)=(13/3, 1, 2)$, as in the $SU(5) \times SU(5)$ string-GUT. Furthermore, if supersymmetry is broken at the unification scale, the Higgs mass is predicted in the range 125 GeV - 170 GeV, depending on the precise values of the top quark mass and $\tan \beta$ parameter.Comment: 11 pages, 4 eps figures, using jpconf style, talk given at CORFU2005, RTN meeting ``The Quest for Unification: Theory Confronts Experiment'', 11 - 18 September 2005, Corfu, Greec

Expression of 72-kDa Gelatinase (MMP-2), Collagenase (MMP-1), and Tissue Metalloproteinase Inhibitor (TIMP) in Primary Pig Skin Fibroblast Cultures Derived from Radiation-Induced Skin Fibrosis

In addition to producing matrix degradation for normal tissue remodeling and repair, matrix metalloproteinases (MMPs) are also involved in various pathologic processes. MMPs and the tissue inhibitor of MMPs (TIMP) were investigated in primary cultures of pig fibroblasts from radiation-induced dermal fibrosis and compared to normal dermal fibroblasts. The free gelatinolytic, collagenolytic, and caseinolytic activities secreted into the culture medium were evaluated against specific 3H denatured collagen type I, native helical collagen, and casein α, respectively. The 72- and 68-kilodalton (kDa) forms of type IV collagenase were investigated by protease zymography and quantified by semi-automated image analysis. Transcription of the interstitial collagenase (MMP-1) and TIMP genes was studied by Northern hybridization analysis. Results revealed that in fibrotic fibroblasts, the amount of MMP-1 mRNA was greatly reduced to undetectable levels whereas the amount of TIMP mRNA was increased fourfold compared to controls. Functional assays using specific 3H substrates demonstrated an overall decrease in free MMP activities. Concomitantly, catheptic collagenolytic activity decreased in fibrotic fibroblast extracts compared to controls. These results indicate that in addition to accumulating large amounts of collagen, proteoglycans, and fibronectin, pig fibroblasts from radiation-induced dermal fibrosis also promote connective tissue matrix formation by repressing MMP-1 and stimulating TIMP expression at the transcriptional level, and by reducing overall free MMP and catheptic collagenolytic activities at the post-transcriptional level. In contrast, enzymography assays and automated image analysis demonstrated no significant change in the 72-kDa type IV collagenase activity of fibrotic pig skin fibroblasts. This opposite regulation of 72-kDa collagenase type IV to that of MMP-1 seems to indicate that it has a specific role in remodeling the extracellular matrix during wound healing, fibrogenesis, and angiogenesis

A new experimental technique for quantifying the galvanic coupling effects on stainless steel during tribocorrosion under equilibrium conditions

Galvanic coupling during tribocorrosion of passive metals at open circuit potential (OCP) generates a wear-accelerated corrosion process within the depassivated area (worn surface) that is electrically in contact with the still passive one. The galvanic coupling effect at OCP was recently modeled using an electrochemical approach allowing for the theoretical quantification of the wear-accelerated corrosion under equilibrium conditions. Despite the usefulness of this model that mathematically determines the electrochemical conditions inside the wear track in terms of anode potential via the approximation of the net anodic current density, an experimental technique allowing for their experimental determination is essential in the effort to verify the galvanic coupling models and further understand the tribocorrosion mechanisms at OCP. In the present work, a new experimental technique based on galvanic current and potential measurements through a Zero-Resistance Ammeter (ZRA) for quantifying the electrode potential and anodic current inside the wear track during rubbing at OCP has been assessed. This experimental set-up has allowed for the first time to determine the prevailing electrochemical conditions (electrode potential and anodic current) inside the wear track by solely exposing the wear track to the electrolyte and physically separating the cathode from the anode (wear track). The effects of sliding wear at open circuit potential have been investigated for a super duplex stainless steel (UNS S32750) in 3.4 wt% NaCl. The new experimental set-up proposed in this work separates the cathode from the anode and exposes solely the wear track to the electrolyte. Using well-established electrochemical theories, the effect of the extent of the galvanic coupling on wear at the open circuit potential conditions has been quantified.The authors would like to thank the support from the European Union for funding C. Torres through the Leonardo da Vinci Mobility program. C.B. von der Ohe and E. Jensen are also acknowledged for having taken part in the initial phase 1151 of this long project. Dr. N. Papageorgiou (NTNU) is also acknowledged for the input and calculations in the modeling part and for preparing Figs. 6-9 of the paper.Espallargas Álvarez, N.; Johnsen, R.; Torres, C.; Igual Muñoz, AN. (2013). A new experimental technique for quantifying the galvanic coupling effects on stainless steel during tribocorrosion under equilibrium conditions. Wear. 307(1-2):190-197. doi:10.1016/j.wear.2013.08.026S1901973071-