Challenges for early discovery in ATLAS and CMS

The challenges for a discovery of new physics with 1 fb^-1 of LHC data for ATLAS and CMS are discussed. Four specific examples are chosen: a deviation of QCD jet distributions at high E_T, high-mass dilepton pairs, Higgs search in the WW decay channel, and low mass supersymmetry.Comment: 6 pages, 17 figure

Supersymmetry searches at the LHC

Recent results in the search for supersymmetry in pp collisions at sqrt(s) = 7 TeV and sqrt(s) = 8 TeV by the ATLAS and CMS experiments at the LHC are reviewed. After discussing features of inclusive analyses and the presentation of results, emphasis will be put on searches for the third generation squarks, on searches for gauginos, and on possible ways supersymmetry could escape the present analyses.Comment: 14 pages, 9 figures. Proceedings of Physics in Collision 201

SUSY Searches at ATLAS

Recent results of searches for supersymmetry by the ATLAS collaboration in up to 2 fb-1 of sqrt(s) = 7 TeV pp collisions at the LHC are reported.Comment: Presented at the 2011 Hadron Collider Physics symposium (HCP-2011), Paris, France, November 14-18 2011, 6 pages, 12 figure

Colour Reconnection in W Decays

The studies of colour reconnection in e+e- -> WW -> 4 jets events at LEP are reviewed. It is shown that the analysis of the particle- and energy flow between jets is sensitive to realistic model predictions. The effects on the W mass measurement are discussed.Comment: LaTeX, 6 pages, 3 postscript figure

Designing signaling environments to steer transcriptional diversity in neural progenitor cell populations

Stem cell populations within developing embryos are diverse, composed of many different subpopulations of cells with varying developmental potential. The structure of stem cell populations in cell culture remains poorly understood and presents a barrier to differentiating stem cells for therapeutic applications. In this paper we develop a framework for controlling the architecture of stem cell populations in cell culture using high-throughput single cell mRNA-seq and computational analysis. We find that the transcriptional diversity of neural stem cell populations collapses in cell culture. Cell populations are depleted of committed neuron progenitor cells and become dominated by a single pre-astrocytic cell population. By analyzing the response of neural stem cell populations to forty distinct signaling conditions, we demonstrate that signaling environments can restructure cell populations by modulating the relative abundance of pre-astrocyte and pre-neuron subpopulations according to a simple linear code. One specific combination of BMP4, EGF, and FGF2 ligands switches the default population balance such that 70% of cells correspond to the committed neurons. Our work demonstrates that single-cell RNA-seq can be applied to modulate the diversity of in vitro stem cell populations providing a new strategy for population-level stem cell control

Mechanisms of poly(vinyl chloride) fire retardance and smoke suppression induced by copper additives

The purpose of this study was to elucidate the mechanisms of PVC fire retardance and smoke suppression induced by copper additives.;The experimental approaches involved: (1) the use of activated copper (Cu{dollar}\sp0{dollar}) to study PVC model-compound reactions and the crosslinking of PVC and (2) the pyrolysis of PVC model compounds in the presence of several copper additives in order to examine all of the possible chemical reactions involved in the formation of heavy products.;The results obtained from experiments with activated copper and allylic chloride model compounds suggest that the reductive coupling mechanism is a viable process in PVC. The Cu{dollar}\sp0{dollar} that caused the coupling was either (a) a slurry resulting from the reduction of CuI {dollar}\cdot{dollar} P(n-Bu){dollar}\sb3{dollar} with lithium naphthalenide or (b) a film created by the pyrolysis of copper(II) formate. Significantly, both the slurry and the film were also demonstrated to be capable of promoting the extensive crosslinking of PVC itself.;In small-scale sealed-ampule model compound pyrolysis experiments, several chemical reactions were revealed that may account for the crosslinking that occurs in copper-containing PVC. These reactions include Lewis-acid-catalyzed oligomerization and chloroalkylation, reductive coupling dimerization, alkene mono-halogenation (rechlorination), and aromatization.;For copper compounds, Lewis-acid catalysis is the major (if not the only) reaction pathway toward crosslinking; while in the case of high-purity copper metal, the reductive coupling mechanism apparently plays a major role in the crosslinking process.;Since the crosslinking of PVC is known to suppress the formation of the volatile aromatics whose combustion generates smoke, the results of this study indicate that copper-promoted Lewis-acid catalysis and reductive coupling dimerization will tend to prevent the evolution of smoke from the burning polymer

Prospects for SUSY searches in CMS and ATLAS

We discuss how the CMS and ATLAS experiments are preparing for the analysis of first LHC data with emphasis on the search for supersymmetry. We will show the importance of the understanding of detector, trigger, reconstruction and backgrounds, and we will present realistic estimates of the reach of CMS and ATLAS.Comment: 9 pages, 12 figures. Contribution to the proceedings of the 16th international conference on supersymmetry and the unification of fundamental interactions, SUSY08, Seoul, Korea, June 16-21, 200

Magnetoelastic coupling and charge correlation lengths in a twin domain of Ba(Fe1−x_{1-x}Cox_{x})2_{2}As2_{2} (x=0.047x=0.047): A high-resolution X-ray diffraction study

The interplay between structure, magnetism and superconductivity in single crystal Ba(Fe$_{1-x}$Co$_{x}$)$_{2}$As$_{2}$ (x=0.047) has been studied using high-resolution X-ray diffraction by monitoring charge Bragg reflections in each twin domain separately. The emergence of the superconducting state is correlated with the suppression of the orthorhombic distortion around \emph{T}$_\texttt{C}$, exhibiting competition between orthorhombicity and superconductivity. Above \emph{T}$_\texttt{S}$, the in-plane charge correlation length increases with the decrease of temperature, possibly induced by nematic fluctuations in the paramagnetic tetragonal phase. Upon cooling, anomalies in the in-plane charge correlation lengths along $a$ ($\xi_{a}$) and $b$ axes ($\xi_{b}$) are observed at \emph{T}$_\texttt{S}$ and also at \emph{T}$_\texttt{N}$ indicative of strong magnetoelastic coupling. The in-plane charge correlation lengths are found to exhibit anisotropic behavior along and perpendicular to the in-plane component of stripe-type AFM wave vector (101)$_{\rm O}$ below around \emph{T}$_\texttt{N}$. The temperature dependence of the out-of-plane charge correlation length shows a single anomaly at \emph{T}$_\texttt{N}$, reflecting the connection between Fe-As distance and Fe local moment. The origin of the anisotropic in-plane charge correlation lengths $\xi_{a}$ and $\xi_{b}$ is discussed on the basis of the antiphase magnetic domains and their dynamic fluctuations.Comment: 7 pages, 6 figures, 34 references, submitted for publication in Physical Review

Sequence similarity between stereocilin and otoancorin points to a unified mechanism for mechanotransduction in the mammalian inner ear

RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.Abstract Background Interaction between hair cells and acellular gels of the mammalian inner ear, the tectorial and otoconial membranes, is crucial for mechanoreception. Recently, otoancorin was suggested to be a mediator of gel attachment to nonsensory cells, but the molecular components of the interface between gels and sensory cells remain to be identified. Hypothesis We report that the inner ear protein stereocilin is related in sequence to otoancorin and, based on its localisation and predicted GPI-anchoring, may mediate attachment of the tectorial and otoconial membranes to sensory hair bundles. Testing It is expected that antibodies directed against stereocilin would specifically label sites of contact between sensory hair cells and tectorial/otoconial membranes of the inner ear. Implications Our findings support a unified molecular mechanism for mechanotransduction, with stereocilin and otoancorin defining a new protein family responsible for the attachment of acellular gels to both sensory and nonsensory cells of the inner ear.Published versio