Antennas for the detection of radio emission pulses from cosmic-ray induced air showers at the Pierre Auger Observatory

The Pierre Auger Observatory is exploring the potential of the radio detection technique to study extensive air showers induced by ultra-high energy cosmic rays. The Auger Engineering Radio Array (AERA) addresses both technological and scientific aspects of the radio technique. A first phase of AERA has been operating since September 2010 with detector stations observing radio signals at frequencies between 30 and 80 MHz. In this paper we present comparative studies to identify and optimize the antenna design for the final configuration of AERA consisting of 160 individual radio detector stations. The transient nature of the air shower signal requires a detailed description of the antenna sensor. As the ultra-wideband reception of pulses is not widely discussed in antenna literature, we review the relevant antenna characteristics and enhance theoretical considerations towards the impulse response of antennas including polarization effects and multiple signal reflections. On the basis of the vector effective length we study the transient response characteristics of three candidate antennas in the time domain. Observing the variation of the continuous galactic background intensity we rank the antennas with respect to the noise level added to the galactic signal

Measurement of the top-quark mass in all-jets tt events in pp collisions at root = 7 TeV

The mass of the top quark is measured using a sample of tt¯ candidate events with at least six jets in the final state. The sample is selected from data collected with the CMS detector in pp collisions at s√=7 TeV in 2011 and corresponds to an integrated luminosity of 3.54 fb−1 . The mass is reconstructed for each event employing a kinematic fit of the jets to a tt¯ hypothesis. The top-quark mass is measured to be 173.49±0.69(stat.)±1.21(syst.) GeV. A combination with previously published measurements in other decay modes by CMS yields a mass of 173.54±0.33(stat.)±0.96(syst.) GeV

Structural mechanism for the selective phosphorylation of DNA-loaded MCM double hexamers by the Dbf4-dependent kinase

Loading of the eukaryotic replicative helicase onto replication origins involves two MCM hexamers forming a double hexamer (DH) around duplex DNA. During S phase, helicase activation requires MCM phosphorylation by Dbf4-dependent kinase (DDK), comprising Cdc7 and Dbf4. DDK selectively phosphorylates loaded DHs, but how such fidelity is achieved is unknown. Here, we determine the cryogenic electron microscopy structure of Saccharomyces cerevisiae DDK in the act of phosphorylating a DH. DDK docks onto one MCM ring and phosphorylates the opposed ring. Truncation of the Dbf4 docking domain abrogates DH phosphorylation, yet Cdc7 kinase activity is unaffected. Late origin firing is blocked in response to DNA damage via Dbf4 phosphorylation by the Rad53 checkpoint kinase. DDK phosphorylation by Rad53 impairs DH phosphorylation by blockage of DDK binding to DHs, and also interferes with the Cdc7 active site. Our results explain the structural basis and regulation of the selective phosphorylation of DNA-loaded MCM DHs, which supports bidirectional replication

Application of the Welfare Quality® protocol in pig slaughterhouses of five countries

European CommissionEuropean Commission: FOOD-CT-2004–506508The objective of the present study is to assess the variability of the measures used in the welfare quality (WQ) protocol for pigs among slaughterhouses in five different countries and to propose alarm and critical thresholds for the calculation of scores for future development of an animal welfare certification scheme. The WQ protocol was applied in 52,468 pigs in 42 slaughterhouses in 5 countries (Portugal, Italy, Finland, Brazil and Spain). The welfare assessment started in the unloading area, where measures of general fear, thermoregulation, slipping and falling, lameness, sickness and mortality were taken. Concerning lairage, space allowance, drinking points, thermoregulation and mortality were considered, and the human-animal relationship was assessed by means of high-pitched vocalisations when pigs were moved from lairage to the stunning system. Finally, stunning effectiveness, skin lesions and presence of pneumonia, pleurisy, pericarditis and white spots on the liver were assessed in the stunning area and after slaughtering the animals. There was a large degree of variability among slaughterhouses for measurements made. For instance, the percentage of animals slipping ranged from 0.4% to 57%. Pigs with signs of recovery after stunning ranged from 0% to 90% and the percentage of carcasses that were severely damaged with skin lesions ranged from 0% to 48%. The data obtained can be useful to establish some thresholds for future uses of the WQ protocol. Electric stunning was associated with more animals recovering consciousness than from CO2