Search for one large extra dimension with the DELPHI detector at LEP2

Single photons detected by the DELPHI experiment at LEP2 in the years 1997-2000 are used to investigate the existence of a single extra dimension in a modifed ADD scenario with slightly warped large extra dimensions. The data collected at centre-of-mass energies between 180 and 209 GeV for an integrated luminosity of ~650 pb^-1 agree with the predictions of the Standard Model and allow a limit to be set on graviton emission in one large extra dimension. The limit obtained on the fundamental mass scale MD is 1.69 TeV at 95% CL, with an expected limit of 1.71 TeV.Comment: 10 pages, 2 figures, contributed to Lepton Photon 2007, Daegu, Kore

The role of spirituality in women\u27s leadership at community colleges

This qualitative research study examined the role of women\u27s leadership in Iowa community colleges. Administrative leaders from community college settings, recommended by their presidents, wrote narratives about effective leadership traits and from these narratives, four women leaders were selected and later interviewed. Key thematic categories were developed from the written and verbal narratives. The resulting data set was then analyzed by a comparative case study approach. Emerging thematic categories were interpreted through the lens of four primary research questions addressing the relationship between gender, spirituality, and authentic leadership. A plethora of issues surfaced from the data. Issues of gender and gender equality rose immediately to the surface. Awareness of gendered issues allowed women leaders to develop a gender literacy that informed their decision-making and their development towards more authentic leadership. Women leaders\u27 knowledge of and sensitivity to hegemonic leadership and historical gender biases as well as their awareness of their own gender-specific leadership traits and qualities enabled women leaders to understand more clearly and contribute more effectively to an emerging sense of authentic leadership. This assisted them in being better members of leadership teams as well as being more prepared to meet the unique needs of their employees. Spirituality and its role in personal and professional leadership development was another important idea that arose from the data. Spirituality, defined as a search for meaning, purpose and connection, was the cyclical process of inner reflection and transcendence to the outer world of life\u27s experiences, reflections, realizations, and choices. As women constructed and refined the meaning and purpose of their life and began to forge more rewarding inter-connections with themselves and others, they felt the corresponding pull to deeper levels of authenticity in themselves and in their leadership roles. The emergence of this authenticity in themselves and their leadership roles was important to these women leaders because in finding themselves they connected to their deeper purpose. These connections were not just internal cognitive and affective patterns but also had an external relational and behavioral dimension to them. Women living these connections as they evolve towards more authentic leadership discover richer personal lives and more effective decision-making

Homotopy Type Theory in Lean

We discuss the homotopy type theory library in the Lean proof assistant. The library is especially geared toward synthetic homotopy theory. Of particular interest is the use of just a few primitive notions of higher inductive types, namely quotients and truncations, and the use of cubical methods.Comment: 17 pages, accepted for ITP 201

Bioaccessibility, bioavailability and toxicity of commercially relevant iron- and chromium-based particles: in vitro studies with an inhalation perspective

<p>Abstract</p> <p>Background</p> <p>Production of ferrochromium alloys (FeCr), master alloys for stainless steel manufacture, involves casting and crushing processes where particles inevitably become airborne and potentially inhaled. The aim of this study was to assess potential health hazards induced by inhalation of different well-characterized iron- and chromium-based particles, i.e. ferrochromium (FeCr), ferrosiliconchromium (FeSiCr), stainless steel (316L), iron (Fe), chromium (Cr), and chromium(III)oxide (Cr₂O₃), in different size fractions using in vitro methods. This was done by assessing the extent and speciation of released metals in synthetic biological medium and by analyzing particle reactivity and toxicity towards cultured human lung cells (A549).</p> <p>Results</p> <p>The amount of released metals normalized to the particle surface area increased with decreasing particle size for all alloy particles, whereas the opposite situation was valid for particles of the pure metals. These effects were evident in artificial lysosomal fluid (ALF) of pH 4.5 containing complexing agents, but not in neutral or weakly alkaline biological media. Chromium, iron and nickel were released to very low extent from all alloy particles, and from particles of Cr due to the presence of a Cr(III)-rich protective surface oxide. Released elements were neither proportional to the bulk nor to the surface composition after the investigated 168 hours of exposure. Due to a surface oxide with less protective properties, significantly more iron was released from pure iron particles compared with the alloys. Cr was predominantly released as Cr(III) from all particles investigated and was strongly complexed by organic species of ALF. Cr₂O₃particles showed hemolytic activity, but none of the alloy particles did. Fine-sized particles of stainless steel caused however DNA damage, measured with the comet assay after 4 h exposure. None of the particles revealed any significant cytotoxicity in terms of cell death after 24 h exposure.</p> <p>Conclusion</p> <p>It is evident that particle and alloy characteristics such as particle size and surface composition are important aspects to consider when assessing particle toxicity and metal release from alloy particles compared to pure metal particles. Generated results clearly elucidate that neither the low released concentrations of metals primarily as a result of protective and poorly soluble surface oxides, nor non-bioavailable chromium complexes, nor the particles themselves of occupational relevance induced significant acute toxic response, with exception of DNA damage from stainless steel.</p

Application of SPS in the fabrication of UN and (U,Th)N pellets from microspheres

In this study, the process involved in the fabrication of a potential accident tolerant fuel is described. Homogeneous uranium nitride microspheres doped with different thorium content were successfully manufactured using an internal gelation process followed by carbothermic reduction, and nitridation. Elemental analysis of the materials showed low carbon and oxygen content, the two major impurities found in the products of carbothermic reduction. Uranium nitride microspheres were pressed and sintered using spark plasma sintering (SPS) to produce pellets with variable density. Final density can be tailored by choosing the sintering temperature, pressure and time. Density values of 77–98% of theoretical density (%TD) were found. As expected, higher temperatures and pressures resulted in a denser material. Furthermore, a direct correlation between the onset sintering temperature and thorium content in the materials was observed. The change of onset temperature has been related to an increment in the activation energy for self-diffusion due to the substitution of uranium atoms by thorium in the crystal structure

Extension and approximation of mm-subharmonic functions

Let $\Omega\subset \mathbb C^n$ be a bounded domain, and let $f$ be a real-valued function defined on the whole topological boundary $\partial \Omega$. The aim of this paper is to find a characterization of the functions $f$ which can be extended to the inside to a $m$-subharmonic function under suitable assumptions on $\Omega$. We shall do so by using a function algebraic approach with focus on $m$-subharmonic functions defined on compact sets. We end this note with some remarks on approximation of $m$-subharmonic functions