The IceCube Data Acquisition System: Signal Capture, Digitization, and Timestamping

IceCube is a km-scale neutrino observatory under construction at the South Pole with sensors both in the deep ice (InIce) and on the surface (IceTop). The sensors, called Digital Optical Modules (DOMs), detect, digitize and timestamp the signals from optical Cherenkov-radiation photons. The DOM Main Board (MB) data acquisition subsystem is connected to the central DAQ in the IceCube Laboratory (ICL) by a single twisted copper wire-pair and transmits packetized data on demand. Time calibration is maintained throughout the array by regular transmission to the DOMs of precisely timed analog signals, synchronized to a central GPS-disciplined clock. The design goals and consequent features, functional capabilities, and initial performance of the DOM MB, and the operation of a combined array of DOMs as a system, are described here. Experience with the first InIce strings and the IceTop stations indicates that the system design and performance goals have been achieved.Comment: 42 pages, 20 figures, submitted to Nuclear Instruments and Methods

A incubação de ovos e larvas em Genidens genidens (Valenciennes) (Siluriformes, Ariidae) da Baía de Guaratuba, Paraná, Brasil Eggs and larvae mouthbreeding in Genidens genidens (Valenciennes) (Siluriformes, Ariidae) from Guaratuba Bay, Paraná, Brazil

<abstract language="eng">At Guaraluba bay, the catfish Genidens genidens shows incubating behavior during the summer months. The larvae are either less or heavier than the eggs, and their stomach analysis confirms the exogenous leeding during incubation. Embryos sizes can increase to 59mm in total lenght and 2,8g in total weight, including the yolksac. It was observed that the largest larvae are guarded by the largest adults, and that the embryo size is similar among individuals from the same adult