Hox-controlled reorganisation of intrasegmental patterning cues underlies Drosophila posterior spiracle organogenesis

10 páginas, 8 figuras. Material complementario del artículo esta disponible en http://dev.biologists.org/cgi/content/full/132/13/3093/DC1Hox proteins provide axial positional information and control segment morphology in development and evolution. Yet how they specify morphological traits that confer segment identity and how axial positional information interferes with intrasegmental patterning cues during organogenesis remain poorly understood. We have investigated the control of Drosophila posterior spiracle morphogenesis, a segment-specific structure that forms under Abdominal-B (AbdB) Hox control in the eighth abdominal segment (A8). We show that the Hedgehog (Hh), Wingless (Wg) and Epidermal Growth Factor Receptor (Egfr) pathways provide specific inputs for posterior spiracle morphogenesis and act in a genetic network made of multiple and rapidly evolving Hox/signalling interplays. A major function of AbdB during posterior spiracle organogenesis is to reset A8 intrasegmental patterning cues, first by reshaping wg and rhomboid expression patterns, then by reallocating the Hh signal and later by initiating de novo expression of the posterior compartment gene engrailed in anterior compartment cells. These changes in expression patterns confer axial specificity to otherwise reiteratively used segmental patterning cues, linking intrasegmental polarity and acquisition of segment identity.This work was supported by the `Centre National de la Recherche Scientifique' (CNRS), grants from `la Ligue Nationale Contre Le Cancer (équipe labellisée La Ligue)', `l'Association pour la Recherche contre le Cancer' (ARC), The Royal Society, The Welcome Trust, the `Minesterio de education y ciencia (BFU 2004 0 96) and ARC and EMBO long term fellowships to S. Merabet.Peer reviewe

CMS Forward-Backward MSGC milestone

The CMS MF1 milestone was set in order to evaluate system aspects of the CMS forward-backward MSGC tracker, to check the design and feasibility of mass production and to set up assembly and test procedures. We describe the construction and the experience gained with the operation of a system of 38 MSGC detectors assembled in six multi-substrate detector modules corresponding to the geometry of the forward-backward MSGC tracker in CMS. These modules were equipped with MSGCs mounted side by side, forming a continuous detector surface of about 0.2 m2. Different designs were tried for these modules. The problems encountered are presented with the proposed solutions. Operation conditions for the 38 MSGCs are reported from an exposure to a muon beam at the CERN SPS. Gain uniformity along the wedge-shaped strip pattern and across the detector modules are shown together with the detection efficiency, the spatial resolution, alignment and edge studies

Systementwicklungen und Messungen zur Auslese und Kalibration von CMS pipeline chips für die angewandte Forschung und Serientests an CMS-Streifendetektoren

The future 14 TeV proton-proton accelerator LHC at CERN serves for the CMS experiment as a high rate source of deep inelastic interactions of quarks and gluons. CMS at the LHC will be one of the "discovery machines" for new particles and theories. The central tracker in the superconducting 4 T-magnet of CMS has to ensure a precise track reconstruction in the space-time. Part I leads to the major tasks of the central tracker for the purpose of preparing the main points of the thesis. In CMS one has to cope with particle fluences of about 10^6cm^-2s^-1 and L1 trigger rates of 100 kHz. System developments have lead to a powerful data acquisition system (DAQ) constructed in VME for emulation of the hardware algorithms in the frontend driver and for research of the properties of CMS microstrip detectors. The experience and the results point to special problems for the operation of the CMS tracker. For most of them solutions will be found which can be emulated in the DAQ or simulated with offline data. If possible perspectives are given for the other cases. This is subject of part II. CMS strip detectors are counted among the silicon microstrip detectors and the in the run up inferior micro strip gas chambers (MSGC). In part III laboratory measurements with prototypes of these detectors will be demonstrated which confirm the benefit of the gained experience in part II. A final comparison of the silicon strip detector and the MSGC eluminates the points of acceptability and deconvolution for the APV pipeline chips. For this a partial publication in the CMS Document Server at CERN has been performed. Unirradiated silicon microstrip detectors have been found to be sophisticated. MSGC-detectors show the expected signal development in time and the anticipated ballistic deficit. The impact of crosstalk effects on the pile-up behaviour has been confirmed. As a result further hints arize for succeeding processes in technology

Systementwicklungen und Messungen zur Auslese und Kalibration von CMS pipeline chips für die angewandte Forschung und Serientests an CMS-Streifendetektoren

The future 14 TeV proton-proton accelerator LHC at CERN serves for the CMS experiment as a high rate source of deep inelastic interactions of quarks and gluons. CMS at the LHC will be one of the "discovery machines" for new particles and theories. The central tracker in the superconducting 4 T-magnet of CMS has to ensure a precise track reconstruction in the space-time. Part I leads to the major tasks of the central tracker for the purpose of preparing the main points of the thesis. In CMS one has to cope with particle fluences of about 10^6cm^-2s^-1 and L1 trigger rates of 100 kHz. System developments have lead to a powerful data acquisition system (DAQ) constructed in VME for emulation of the hardware algorithms in the frontend driver and for research of the properties of CMS microstrip detectors. The experience and the results point to special problems for the operation of the CMS tracker. For most of them solutions will be found which can be emulated in the DAQ or simulated with offline data. If possible perspectives are given for the other cases. This is subject of part II. CMS strip detectors are counted among the silicon microstrip detectors and the in the run up inferior micro strip gas chambers (MSGC). In part III laboratory measurements with prototypes of these detectors will be demonstrated which confirm the benefit of the gained experience in part II. A final comparison of the silicon strip detector and the MSGC eluminates the points of acceptability and deconvolution for the APV pipeline chips. For this a partial publication in the CMS Document Server at CERN has been performed. Unirradiated silicon microstrip detectors have been found to be sophisticated. MSGC-detectors show the expected signal development in time and the anticipated ballistic deficit. The impact of crosstalk effects on the pile-up behaviour has been confirmed. As a result further hints arize for succeeding processes in technology

Readout and Calibration of CMS Pipeline Chips to Examine the Signal Development of Tracking Strip Detectors

During the last years many investigations have been made to come to an optimal strip detector for the CMS outer tracker, accompanied in the main items by laboratory experiments in Aachen. Prototype testing of MSGCs and a silicon strip detector resulted in a multifaceted VME system with respect to hardware and software. The system includes a DAQ part as well as software tools to check the front end hardware. Results from measurements will be given for the hybrids and the strip detectors. External charge injection and a Strontium 90 source are used to compare the silicon and the MSGC detector

Beam test performance of a closed microstrip gas chamber module for the CMS forward tracker

We built and tested a closed MSGC module for the CMS forward tracker with trapezoidal strip patterns on 300 m DESAG263 glass substrates produced by OPTIMASK. In the 100 GeV X5 --beam at CERN, we investigated the behaviour of this module foreseen for four wedge shaped substrates, 512 anode strips each. Good separation of signal and noise was achieved and efficiencies reached 97%. The variation of gain across the strip pattern was examined. 1 Introduction Microstrip gas chambers (MSGCs) [1, p.28] are foreseen to set up the outer layers of the inner tracking system in CMS [1]. Since their introduction by A. Oed [2] they have attracted a lot of interest due to good position-- and two-track resolution, high rate capability and lower costs compared to silicon detectors. In this note we concentrate on the mechanical setup of an MSGC module designed for the CMS forward tracker. Therefore we used trapezoidal strip patterns on wegde shaped glass substrates and built a banana--shaped detector ..

Large scale test of wedge shaped micro strip gas counters

In order to check the system aspects of the forward-backward MSGC tracker designed for the future CMS experiment at LHC, 38 trapezoidal MSGC counters assembled in six multi-substrates detector modules were built and exposed to a muon beam at the CERN SPS. Results on the gain uniformity along the wedge-shaped strip pattern and across the detector modules are shown together with measurements of the detection efficiency and the spatial resolution. (8 refs)