A New Technique to Compute Long-Range Wakefields in Accelerating Structures

A new technique is proposed to compute the coupling impedances and the long-range wakefields based on a scattering-matrix formalism which relies heavily upon post-processed data from the commercial finite-element code HFSS. To illustrate the speed of this technique, the procedures to compute the long-range wakefields of conventional constant-impedance structures and of structures damped with waveguides are presented. The efficiency and accuracy of the technique is achieved because the characteristics of periodic structures can be computed using single-cell data. Damping and synchronism effects are determined from such a computation

Process disturbances in agricultural biogas production—causes, mechanisms and effects on the biogas microbiome: A review

Disturbances of the anaerobic digestion process reduce the economic and environmental performance of biogas systems. A better understanding of the highly complex process is of crucial importance in order to avoid disturbances. This review defines process disturbances as significant changes in the functionality within the microbial community leading to unacceptable and severe decreases in biogas production and requiring an active counteraction to be overcome. The main types of process disturbances in agricultural biogas production are classified as unfavorable process temperatures, fluctuations in the availability of macro- and micronutrients (feedstock variability), overload of the microbial degradation potential, process-related accumulation of inhibiting metabolites such as hydrogen (H 2 ), ammonium/ammonia (NH 4 + /NH 3 ) or hydrogen sulphide (H 2 S) and inhibition by other organic and inorganic toxicants. Causes, mechanisms and effects on the biogas microbiome are discussed. The need for a knowledge-based microbiome management to ensure a stable and efficient production of biogas with low susceptibility to disturbances is derived and an outlook on potential future process monitoring and control by means of microbial indicators is provided

Nonlinear Response of Orbit Monitors

The LEP Spectrometer is used to determine beam energy by measuring the bending angle of the beam in a dipole magnet, using six beam position monitors (BPMs), which must have an accuracy close to 10-6 m. The BPMs feature an Al block with an elliptical aperture and four capacitive pickup electrodes; their response depends on the pickup geometry, the aperture shape and the size of the beam. The beam size varies from BPM to BPM, which may give shifts of the measured position. We have investigated the implications of such shifts on the Spectrometer performance. We summarise our current understanding of the BPM behaviour using both a computer model of their response and measurements

The LEP Energy Spectrometer

The energy of the circulating particles in the LEP storage ring is predicted by a model based on nuclear magnetic resonance (NMR) probes measuring the bending magnetic field. This model is calibrated by the method of resonant depolarisation. Since the latter technique is limited in energy range an independent method to confirm the NMR based model is applied. The spectrometer has been installed to determine the beam energy with a relative accuracy of 1 ×10 -4 . It consists of a precisely calibrated bending magnet flanked by six beam position monitors. The beam energy is determined by measuring the deflection angle of the particles and the integrated bending field. In the 1999 LEP operation period the spectrometer was commissioned and the first energy measure-ments in the regime of 90 GeV were performed. A relative scatter of 1 .5 ×10 -4 was observed with no systematic deviation from the energy model. The scatter is expected to be reduced in the 2000 LEP run by minimising several systematic effects of the measurement procedure. Die Energie der im LEP Speicherring zirkulierenden Teilchen wird aus der Messung des Ablenkfeldes mit Hilfe von Kernspinresonanz (KSR) Instrumenten bestimmt. Dieses KSR Modell wird durch die Methode der Resonanten Depolarisation kalibriert. Da Letztere nur einen Teil des LEP Energiebereichs abdeckt, wurde das Spektrometer als eine unabhängige Methode zur Über-pr fung des Modells entwickelt. Es soll die Energie der Teilchen mit einer relativen Genauigkeit von 1 ×10 -4 bestimmen. Das Spektrometer besteht aus einem exakt kalibriertem Ablenkmag-neten und drei Strahl Positions Monitoren auf jeder Seite. Die Energie des Strahls wird aus der Messung des Ablenkwinkels der Teilchen und dem integralen Magnetfeld bestimmt. Während der LEP Operationsperiode 1999 wurde das Spektrometer in Betrieb genommen und die ersten Energiemessungen im Bereich von 90 GeV durchgef hrt. Es wurde eine relative Streuung der Energien von 1 .5 ×10 -4 ohne systematische Abweichungen vom KSR Modell beobachtet. Durch die Minimierung systematischer Effekte bei der Messung wird eine Verringerung der Streuung während der LEP Operationsperiode 2000 erwartet

Improving patient and caregiver new medication education using an innovative teach-back toolkit

Background: Patients and caregivers are often not adequately informed about new medications. Nurses can lead innovations that improve new medication education. Local Problem: Healthcare Consumer Assessment of Healthcare Providers and Systems (HCAHPS) scores on medication questions trailed state and national levels in one Midwestern hospital. Methods: This quality improvement project, guided by the Ottawa Model of Research Use and the Always Use Teach-back! innovative toolkit, used a 1-group pre- and post education design with RNs, patients, and caregivers. Intervention: RNs (n = 25) were observed in patient/caregiver education and surveyed in confidence/conviction in the teach-back method before and after education. Patients’ (n = 74) and caregivers’ (n = 33) knowledge was assessed. Results: RNs reported significant increases in conviction in the importance of (P \u3c .0001), confidence in using (P \u3c .0001), and frequency in using (P \u3c .0001) teach-back. With teach-back, both patients and caregivers recalled the purpose and side effects of new medications. Specific HCAHPS scores increased from 6% to 10%. Conclusion: The teach-back method strengthened safe nursing practice and enhanced quality in new medication education

Accuracy of the LEP Spectrometer Beam Orbit Monitors

At the LEP e+/e- collider, a spectrometer is used to determine the beam energy with a target accuracy of 10-4. The spectrometer measures the lattice dipole bending angle of the beam using six beam position monitors (BPMs). The required calibration error imposes a BPM accuracy of a 10-6 m corresponding to a relative electrical signal variation of 2. 10-5. The operating parameters have been compared with beam simulator results and non-linearBPM response simulations. The relative beam current variations between 0.02 and 0.03 and position changes of 0.1 mm during the fills of last year lead to uncertainties in the orbit measurements of well below 10-6 m. For accuracy tests absolute beam currents were varied by a factor of three. The environment magnetical field is introduced to correct orbit readings. The BPM linearity and calibration was checked using moveable supports and wire position sensors. The BPM triplet quantity is used to determine the orbit position monitors accuracy. The BPM triplet changed during the fills between 1 and 2 10-6 m RMS, which indicates a single BPM orbit determination accuracy between 1 and 1.5 10-6 m

Performance of BPM Electronics for the LEP Spectrometer

At the LEP e+/e- collider at CERN, Geneva, a Spectrometer is used to determine the beam energy with a relative accuracy of 10-4. The Spectrometer measures the change in bending angle in a well-characterised dipole magnet as LEP is ramped. The beam trajectory is obtained using three beam position monitors (BPMs) on each side of the magnet. The error on each BPM measurement should not exceed 1 micron if the desired accuracy on the bending angle is to be reached. The BPMs used consist of an aluminium block with an elliptical aperture and four capacitive button pickup electrodes. The button signals are fed to customised electronics supplied by Bergoz. The electronics use time multiplexing of individual button signals through a single processing chain to optimise for long-term stability. We report on our experience of the performance of these electronics, describing measurements made with test signals and with beam. We have implemented a beam-based calibration procedure and have monitored the reproducibility of the measurements obtained over time. Measurements show that a relative accuracy better than 300 nm is achievable over a period of 1 hr

'Big things in small packages: The genetics of filamentous phage and effects on fitness of their host'

© FEMS 2015. This review synthesizes recent and past observations on filamentous phages and describes how these phages contribute to host phentoypes. For example, the CTXφ phage of Vibrio cholerae encodes the cholera toxin genes, responsible for causing the epidemic disease, cholera. The CTXφ phage can transduce non-toxigenic strains, converting them into toxigenic strains, contributing to the emergence of new pathogenic strains. Other effects of filamentous phage include horizontal gene transfer, biofilm development, motility, metal resistance and the formation of host morphotypic variants, important for the biofilm stress resistance. These phages infect a wide range of Gram-negative bacteria, including deep-sea, pressure-adapted bacteria. Many filamentous phages integrate into the host genome as prophage. In some cases, filamentous phages encode their own integrase genes to facilitate this process, while others rely on host-encoded genes. These differences are mediated by different sets of 'core' and 'accessory' genes, with the latter group accounting for some of the mechanisms that alter the host behaviours in unique ways. It is increasingly clear that despite their relatively small genomes, these phages exert signficant influence on their hosts and ultimately alter the fitness and other behaviours of their hosts

Calibration of centre-of-mass energies at LEP 2 for a precise measurement of the W boson mass

The determination of the centre-of-mass energies for all LEP 2 running is presented. Accurate knowledge of these energies is of primary importance to set the absolute energy scale for the measurement of the W boson mass. The beam energy between 80 and 104 GeV is derived from continuous measurements of the magnetic bending field by 16 NMR probes situated in a number of the LEP dipoles. The relationship between the fields measured by the probes and the beam energy is defined in the NMR model, which is calibrated against precise measurements of the average beam energy between 41 and 61 GeV made using the resonant depolarisation technique. The validity of the NMR model is verified by three independent methods: the flux-loop, which is sensitive to the bending field of all the dipoles of LEP; the spectrometer, which determines the energy through measurements of the deflection of the beam in a magnet of known integrated field; and an analysis of the variation of the synchrotron tune with the total RF voltage. To obtain the centre-of-mass energies, corrections are then applied to account for sources of bending field external to the dipoles, and variations in the local beam energy at each interaction point. The relative error on the centre-of-mass energy determination for the majority of LEP 2 running is 1.2 x 10^{-4}, which is sufficiently precise so as not to introduce a dominant uncertainty on the W mass measurement.Comment: 79 pages, 45 figures, submitted to EPJ

Determination of the Accuracy of Wire Position Sensors

An energy spectrometer has been installed in the LEP accelerator to determine the beam energy with a relative accuracy of 10-4. A precisely calibrated bending magnet is flanked by 6 beam position monitors (BPM). The beam energy is determined by measuring the deflection angle of the LEP beams and the integrated bending field. An accuracy of less than 10-6 m on the beam position is necessary to reach the desired accuracy on the LEP beam energy. Capacitive wire positioning sensors are used to determine the relative mounting stability of each BPM and to calibrate the beam position monitors. Two-dimensional sensors are attached to each side of every BPM support and provide a position measurement with respect to two stretched wires mounted on either side of the LEP beam pipe. The fixing points of each wire are monitored by additional reference sensors. The position information is digitised via a multiplexed high accuracy digital voltmeter and read out continuously during LEP operations. Wire position sensor accuracy was tested in the laboratory with a laser interferometer, while relative accuracy tests are performed in the LEP environment. Systematic effects of synchrotron radiation on the wire position sensor performance were studied