Lichens and bryophytes are important groups of organisms in almost all natural ecosystems in that they contribute to carbon and nitrogen cycles, and the formation, stability and infiltration properties of soils. Few Australian studies include the response of these organisms to fire at landscape scales. Here we report on the response of cryptogams to post-fire age and its heterogeneity (i.e., a mosaic of fire ages compared to a single fire age) across jarrah forest blocks in southwestern Australia. Three vegetation units were sampled within each of two adjoining forest blocks of 5000 and 6700 ha. Samples were collected in 2005 and 2010, 2.5 and 7.5 years after wildfire in the northern forest block. The other forest block was burned to produce mosaics of fire ages that differed in structure between sampling in 2005 and 2010. The northern block was sampled in two sub-blocks, each with two replicate sample grids of the three vegetation units (12 sample grids), whereas the mosaics were similarly sampled (six sample grids) in the southern block. Each sample grid consisted of four 2 × 50 m plots within which the presence–absence of species within the total area sampled (400 m2) was recorded. Sixty-seven species were recorded from 36 samples: 40 macrolichens, 20 mosses and seven liverworts. We examined effects of vegetation unit, fire age and heterogeneity on the composition of cryptogam assemblages using Per MANOVA. Cryptogam assemblage composition and richness were associated with vegetation units within jarrah forests and they varied with time since fire. Lichen and bryophyte richness was greatest in landscapes composed of a mosaic of post-fire seral stages and least in pyrically homogenous landscapes 2.5 years after fire. The influence of fire age on cryptogam species richness and assemblage compositions in the deliberately created mosaics is a practical demonstration of the ability of such a landscape to conserve long unburned patches and provide a range of seral stages to maintain cryptogam diversity.

The ATLAS experiment under construction at CERN is due to begin operation at the end of 2007. The detector will record the results of proton-proton collisions at a center-of-mass energy of 14 TeV. The trigger is a three-tier system designed to identify in real-time potentially interesting events that are then saved for detailed offline analysis. The trigger system will select approximately 200 Hz of potentially interesting events out of the 40 MHz bunch-crossing rate (with 109 interactions per second at the nominal luminosity).

The ATLAS readout subsystem is the main interface between ∼ 1600 detector front-end readout links and the higher-level trigger farms. To handle the high event rate (up to 100 kHz) and bandwidth (up to 160 MB/s per link) the readout PCs are equipped with four ROBIN (readout buffer input) cards. Each ROBIN attaches to three optical links, provides local event buffering for approximately 300 ms and communicates with the higher-level trigger system for data and delete requests. According to the ATLAS baseline architecture this communication runs via the PCI bus of the host PC. In addition, each ROBIN provides a private Gigabit Ethernet port which can be used for the same purpose. Operational monitoring is performed via PCI. This paper presents a summary of the ROBIN hardware and software together with measurements results obtained from various test setups.

This article presents the base-line design and implementation of the ATLAS Rigger and Data Acquisition system, in particular the Data Flow and High Level Rigger components. The status of the installation and commissioning of the system is also presented.

In the ATLAS experiment at the LHC, the output of readout hardware specific to each subdetector will be transmitted to buffers, located on custom made PCI cards ("ROBINs"). The data consist of fragments of events accepted by the first-level trigger at a maximum rate of 100 kHz. Groups of four ROBINs will be hosted in about 150 read-out subsystem (ROS) PCs. Event data are forwarded on request via Gigabit Ethernet links and switches to the second-level trigger or to the event builder. In this paper a discussion of the functionality and real-time properties of the ROS is combined with a presentation of measurement and modeling results for a testbed with a size of about 20% of the final DAQ system. Experimental results on strategies for optimizing the system performance, such as utilization of different network architectures and network transfer protocols, are presented for the testbed, together with extrapolations to the full system

The pre-series test bed is used to validate the technology and implementation choices by comparing the final ATLAS readout requirements, to the results of performance, functionality and stability studies. We show that all the components which are not running reconstruction algorithms match the final ATLAS requirements. For the others, we calculate the amount of time per event that could be allocated to run these not-yet-finalized algorithms. We also report on the experience gained during these studies while interfacing with a sub-detector for the first time at the experimental area.

The base-line design and implementation of the ATLAS DAQ DataFlow system is described. The main components of the DataFlow system, their interactions, bandwidths, and rates are discussed and performance measurements on a 10% scale prototype for the final ATLAS TDAQ DataFlow system are presented. This prototype is a combination of custom design components and of multithreaded software applications implemented in C++ and running in a Linux environment on commercially available PCs interconnected by a fully switched gigabit Ethernet network.

The ATLAS trigger reduces the rate of interesting events to be recorded for off-line analysis in three successive levels from 40 MHz to about 100 kHz, about 2 kHz and about 200 Hz. The High Level Triggers and Data Acquisition System are designed to profit from commodity computing and networking components to achieve the required performance. We discuss Data Flow aspects of the design of the Second Level Trigger (LVL2) and present results of performance measurements.

In this paper, simulation ("computer modeling") of the Trigger/data acquisition (DAQ) system of the ATLAS experiment at the LHC accelerator is discussed. The system will consist of a few thousand end nodes, which are interconnected by a large Ethernet network. The nodes will run various applications under the Linux operating system (OS). Predictions for the latency, throughput and queue development in various places have been obtained. Results are presented with respect to the application of traffic shaping to reduce the probability of possible frame loss (which may cause severe performance degradation).

The Level-2 Trigger Pilot Project of ATLAS, one of the two general purpose LHC experiments, is part of the on-going programme to develop the ATLAS High Level Triggers (HLT). The Level-2 Trigger will receive events at up to 100 kHz, which has to be reduced to a rate suitable for full event-building of the order of 1 kHz. To reduce the data collection bandwidth and processing power required for the challenging Level-2 task it is planned to use Region of Interest guidance (from Level-1) and sequential processing. The Pilot Project included the construction and use of testbeds of up to 48 processing nodes, development of optimised components and computer simulations of a full system. It has shown how the required performance can be achieved, using largely commodity components and operating systems, and validated an architecture for the Level-2 system. This paper describes the principal achievements and conclusions of this project.

Summary In 1985, new silvicultural treatments were implemented in jarrah (Eucalyptus marginata) forests available for wood production. As part of a scientific investigation into the ecological impacts of two of these treatments, gap cutting and shelterwood cutting, a survey was conducted 4 years after logging to examine the effects of these treatments on understorey vegetation species richness and abundance. Sampling scale was found to be an important factor affecting the results and subsequent interpretation of impacts. At the coupe scale, native plant species richness in unlogged coupe buffers was similar to that in adjacent logged patches. However, the mean number of species per 1 m2 was 20%-30% higher in the unlogged buffers than the logged patches. At all sampling scales, the abundance (number of individual plants) of native plants was 20%-35% higher in the buffers, but the abundance of introduced (weed) species was significantly higher in the logged patches. The abundance of weeds, which are mostly annual grasses and short-lived herbs, is likely to diminish with time. The time to recovery of native species abundance and the ecological significance of this is uncertain. Given the reported low seedling regeneration rate and limited dispersal capacity of many woody shrubs and perennial herbs, they are unlikely to return to pre-logging levels in the medium term. We attribute the reduction in the abundance of native plants mainly to mechanical soil disturbance, which ranged from 60% to 80% of the area of logged coupes, physical damage to the vegetation associated with logging and to intense heating of the topsoil during the post-logging silvicultural burn. Recommendations are made for reducing the negative impacts of logging operations on the understorey.