Characterizing, managing and monitoring the networks for the ATLAS data acquisition system

Particle physics studies the constituents of matter and the interactions between them. Many of the elementary particles do not exist under normal circumstances in nature. However, they can be created and detected during energetic collisions of other particles, as is done in particle accelerators. The Large Hadron Collider (LHC) being built at CERN will be the world's largest circular particle accelerator, colliding protons at energies of 14 TeV. Only a very small fraction of the interactions will give raise to interesting phenomena. The collisions produced inside the accelerator are studied using particle detectors. ATLAS is one of the detectors built around the LHC accelerator ring. During its operation, it will generate a data stream of 64 Terabytes/s. A Trigger and Data Acquisition System (TDAQ) is connected to ATLAS -- its function is to acquire digitized data from the detector and apply trigger algorithms to identify the interesting events. Achieving this requires the power of over 2000 computers plus an interconnecting network capable of sustaining a throughput of over 150 Gbit/s with minimal loss and delay. The implementation of this network required a detailed study of the available switching technologies to a high degree of precision in order to choose the appropriate components. We developed an FPGA-based platform (the GETB) for testing network devices. The GETB system proved to be flexible enough to be used as the ba sis of three different network-related projects. An analysis of the traffic pattern that is generated by the ATLAS data-taking applications was also possible thanks to the GETB. Then, while the network was being assembled, parts of the ATLAS detector started commissioning -- this task relied on a functional network. Thus it was imperative to be able to continuously identify existing and usable infrastructure and manage its operations. In addition, monitoring was required to detect any overload conditions with an indication where the excess demand was being generated. We developed tools to ease the maintenance of the network and to automatically produce inventory reports. We created a system that discovers the network topology and this permitted us to verify the installation and to track its progress. A real-time traffic visualization system has been built, allowing us to see at a glance which network segments are heavily utilized. Later, as the network achieves production status, it will be necessary to extend the monitoring to identify individual applications' use of the available bandwidth. We studied a traffic monitoring technology that will allow us to have a better understanding on how the network is used. This technology, based on packet sampling, gives the possibility of having a complete view of the network: not only its total capacity utilization, but also how this capacity is divided among users and software applicati ons. This thesis describes the establishment of a set of tools designed to characterize, monitor and manage complex, large-scale, high-performance networks. We describe in detail how these tools were designed, calibrated, deployed and exploited. The work that led to the development of this thesis spans over more than four years and closely follows the development phases of the ATLAS network: its design, its installation and finally, its current and future operation

Characterization of SPL4\u27s role in drought stress and trichome development in alfalfa

The impacts of climate change are expected to increase the demand for crops that are resistant to drought stress. Understanding the molecular mechanisms involved in the response of plants to such stresses is thus crucial for preventing losses in crop yield. In this study, the role of alfalfa SPL4, a target of the non-coding RNA, miR156, was examined in response to drought stress and with respect to the development of trichomes. We found that transgenic alfalfa plants with RNAi-silenced SPL4 exhibited increased trichome density under both control and drought conditions. Furthermore, in response to withholding water for 14 days, SPL4-RNAi plants exhibited increased root length, water content, chlorophyll content, stomatal conductance, and increased water potential in leaves when compared to wild-type plants. RT-qPCR revealed that SPL4-RNAi plants displayed altered expression levels of genes involved in drought tolerance (SPL9, SPL13), antioxidant biosynthesis (CAT), and trichome production (GL1, GL3). This study demonstrates that SPL4 has a role in both trichome development and in the drought stress response, making it a potential target for the improvement of alfalfa and potentially other crops

The Use of Ultrasound in the Treatment Process of Wastewater. A review

In this paper, different types of ultrasound devices for the treatment process of wastewater are presented. The use of ultrasound in treatment processes is a method of perspective, an alternative to conventional methods. This technique is based  in the cavitation phenomenon that occurs in liquids at ultrasonic irradiation and it is used to enhance or ensure the processes of heat and mass transfer. Some of the main advantages of using ultrasound, namely low consumption of additional material or energy, are presented in this paper. The categories of the ultrasonic transmitters distinguished on the basis of the principle underlying the generation of acoustic waves are described

Treatment of Ammonia Wastewater by Ultrasound. Part I: The Influence of the Ultrasound Energy on the Ultrasound Bath Temperature

The industrial ammonia water decontamination depending on the sample temperature is monitored by this study. The treatment was conducted by the UP100S ultrasound generator (Hielscher Ultrasound Technology, Germany), operating at 30 kHz frequency and acoustic power densities of 90 W/cm2 and 460 W/cm2 respectively. The effect of sonication both on the bath temperature and ammonia removal, based on treatment time, is presented in this paper. Experiments were carried out according to different parameters, so as the sample temperature variation by ultrasonic treatment to be determined. Studied parameters were: the operating mode variation (continuous or intermittent), the additional aeration and the application of a cooling water serpentine. Based on the results, the ammonia removal efficiency is improved by the heating produced by the ultrasonic energy

Crystalline optical cavity at 4 K with thermal noise limited instability and ultralow drift

Crystalline optical cavities are the foundation of today's state-of-the-art ultrastable lasers. Building on our previous silicon cavity effort, we now achieve the fundamental thermal noise-limited stability for a 6 cm long silicon cavity cooled to 4 Kelvin, reaching $6.5\times10^{-17}$ from 0.8 to 80 seconds. We also report for the first time a clear linear dependence of the cavity frequency drift on the incident optical power. The lowest fractional frequency drift of $-3\times10^{-19}$/s is attained at a transmitted power of 40 nW, with an extrapolated drift approaching zero in the absence of optical power. These demonstrations provide a promising direction to reach a new performance domain for stable lasers, with stability better than $1\times10^{-17}$ and fractional linear drift below $1\times10^{-19}$/s

Primary Headaches and their Relationship with the Autonomic Nervous System

Headache disorders, described as early as 3000 BC, represent both a treatment challenge and a serious public health concern, with impact on the individual and society. Existing research in primary headache syndromes (not being caused by any underlying problem) focuses mainly on pain mechanisms. However, the painful symptomatology is the main encounter for the decreased quality of life and discomfort, the vegetative manifestations that frequently accompany the cephalalgic syndromes represent an important source of distress. Despite the advancement of the understanding of the molecular basis of headache disorders and neurovascular complex interactions, there is still lack of a cohesive understanding of the neurovegetative modulation in different types of primary cephalalgic syndromes. The aim of this chapter is to present an overview of the neurochemical mechanisms and pathways, which subtend dysautonomic manifestations in headache