Preliminary trials with optical fiber dosimeters at TTF

Ionizing radiation leads to a degradation of the light transmitting properties of fiber optic cables. These effects usually place restrictions on where they can be used in a particle accelerator facility. These effects can also be used to our advantage, the losses from a particle beam create wavelength dependant increases of attenuation by absorption and scattering which can be measured using Optical Time Domain Reflectometry (OTDR). From these measurements a measure of the radiation dose received can be inferred

BEAM PROFILE MEASUREMENT WITH OPTICAL FIBER SENSORS AT FLASH

Abstract The system is intended to determine the beam profile at the DESY-FLASH undulator section as well as measuring beam losses with high spatial resolution. The measurement setup is based on wire scanners, optical fibers which are symmetrically mounted around the beam line over the full length (30 m) of the undulator section, a signal conditioning unit and a data acquisition system. The optical fibers are used as beam loss sensors, and depending on the software configuration, the setup is working either as a beam loss position monito

Efficient frequency doubler for the soft X-ray SASE FEL at the TESLA Test Facility

This paper describes an effective frequency doubler scheme for SASE free electron lasers. It consists of an undulator tuned to the first harmonic, a dispersion section, and a tapered undulator tuned to the second harmonic. The first stage is a conventional soft X-ray SASE FEL. Its gain is controlled in such a way that the maximum energy modulation of the electron beam at the exit is about equal to the local energy spread, but still far away from saturation. When the electron bunch passes through the dispersion section this energy modulation leads to effective compression of the particles. Then the bunched electron beam enters the tapered undulator and produces strong radiation in the process of coherent deceleration. We demonstrate that a frequency doubler scheme can be integrated into the SASE FEL at the TESLA Test Facility at DESY, and will allow to reach 3 nm wavelength with GW-level of output peak power. This would extend the operating range of the FEL into the so-called water window and significantly expand the capabilities of the TTF FEL user facility.Comment: 17 pages, 13 figure

First Observation of Self-Amplified Spontaneous Emission in a Free-Electron Laser at 109 nm Wavelength

We present the first observation of Self-Amplified Spontaneous Emission (SASE) in a free-electron laser (FEL) in the Vacuum Ultraviolet regime at 109 nm wavelength (11 eV). The observed free-electron laser gain (approx. 3000) and the radiation characteristics, such as dependency on bunch charge, angular distribution, spectral width and intensity fluctuations all corroborate the existing models for SASE FELs.Comment: 6 pages including 6 figures; e-mail: [email protected]

K201 improves aspects of the contractile performance of human failing myocardium via reduction in Ca2+ leak from the sarcoplasmic reticulum

In heart failure, intracellular Ca2+ leak from cardiac ryanodine receptors (RyR2s) leads to a loss of Ca2+ from the sarcoplasmic reticulum (SR) potentially contributing to decreased function. Experimental data suggest that the 1,4-benzothiazepine K201 (JTV-519) may stabilise RyR2s and thereby reduce detrimental intracellular Ca2+ leak. Whether K201 exerts beneficial effects in human failing myocardium is unknown. Therefore, we have studied the effects of K201 on muscle preparations from failing human hearts. K201 (0.3 μM; extracellular [Ca2+]e 1.25 mM) showed no effects on contractile function and micromolar concentrations resulted in negative inotropic effects (K201 1 μM; developed tension −9.8 ± 2.5% compared to control group; P < 0.05). Interestingly, K201 (0.3 μM) increased the post-rest potentiation (PRP) of failing myocardium after 120 s, indicating an increased SR Ca2+ load. At high [Ca2+]e concentrations (5 mmol/L), K201 increased PRP already at shorter rest intervals (30 s). Strikingly, treatment with K201 (0.3 μM) prevented diastolic dysfunction (diastolic tension at 5 mmol/L [Ca2+]e normalised to 1 mmol/L [Ca2+]e: control 1.26 ± 0.06, K201 1.01 ± 0.03, P < 0.01). In addition at high [Ca2+]e, K201 (0.3 μM) treatment significantly improved systolic function [developed tension +27 ± 8% (K201 vs. control); P < 0.05]. The beneficial effects on diastolic and systolic functions occurred throughout the physiological frequency range of the human heart rate from 1 to 3 Hz. Upon elevated intracellular Ca2+ concentration, systolic and diastolic contractile functions of terminally failing human myocardium are improved by K201

Is music enriching for group-housed captive chimpanzees (Pan troglodytes)?

Many facilities that house captive primates play music for animal enrichment or for caregiver enjoyment. However, the impact on primates is unknown as previous studies have been inconclusive. We conducted three studies with zoo-housed chimpanzees (Pan troglodytes) and one with group-housed chimpanzees at the National Centre for Chimpanzee Care to investigate the effects of classical and pop/rock music on various variables that may be indicative of increased welfare. Study one compared the behaviour and use of space of 18 animals when silence, classical or pop/rock music was played into one of several indoor areas. Overall, chimpanzees did not actively avoid the area when music was playing but were more likely to exit the area when songs with higher beats per minute were broadcast. Chimpanzees showed significantly fewer active social behaviours when music, rather than silence, was playing. They also tended to be more active and engage in less abnormal behaviour during the music but there was no change to either self-grooming or aggression between music and silent conditions. The genre of music had no differential effects on the chimpanzees’ use of space and behaviour. In the second study, continuous focal observations were carried out on three individuals with relatively high levels of abnormal behaviour. No differences in behaviour between music and silence periods were found in any of the individuals. The final two studies used devices that allowed chimpanzees to choose if they wanted to listen to music of various types or silence. Both studies showed that there were no persistent preferences for any type of music or silence. When taken together, our results do not suggest music is enriching for group-housed captive chimpanzees, but they also do not suggest that music has a negative effect on welfare

Geriatric patients' expectations of their physicians: findings from a tertiary care hospital in Pakistan

<p>Abstract</p> <p>Background</p> <p>Geriatric health is a neglected and under-explored area internationally and in Pakistan. We aimed to ascertain the expectations of the geriatric patients from their physicians and the factors associated with patient satisfaction in this particular age bracket.</p> <p>Methods</p> <p>A cross-sectional survey was carried out at a tertiary care teaching hospital in Karachi, Pakistan. Data collection was carried out via face-to-face interviews based on structured, pre-tested questionnaires. All consenting individuals aged 65 years or above were recruited into the study. Convenience sampling was used to draw the sample. The data was analyzed using SPSS version 16. Geriatric patient's expectations from physicians were elicited using a set of 11 questions that were graded on a scale of 1-3 where 1 = not important, 2 = important, 3 = very important.</p> <p>Results</p> <p>Three hundred and eighty geriatric patients were interviewed. The response rate of this study was 89.8%. The mean age of the respondents was 73.4 ± 6.8 years. Two hundred and forty eight respondents (65.3%) were female. Diabetes mellitus (53.7%), hypertension (59.5%), arthritis (40.5%) and renal disease (32.1%) were common ailments among geriatric patients. More than 50% of the patients were visiting their physicians once every two to three months. Discussing treatment options and letting patients make the final decision (79.2%), prescribing minimum possible medications (84.5%), physician's holistic knowledge about the spectrum of care issues for geriatric patients (79.2%), being given a realistic but optimistic picture of future health by physicians (85.5%) were ranked as very important expectations by patients from their physicians. Cumulative household income (p = 0.005), most important health complaint (p = 0.01) and frequency of experiencing health complaint (p < 0.001) emerged as independent predictors of the satisfaction of geriatric patients from care provided by physicians.</p> <p>Conclusion</p> <p>We have documented the expectations of the geriatric patients from their physicians in a developing country. Physicians belonging to all disciplines should keep these expectations in mind during clinical encounters with geriatric patients.</p

Beam Loss and Beam Profile Monitoring with Optical Fibers

Beam losses and beam profiles at particle accelerators are determined by measuring the ionizing radiation outside the vacuum chamber. Four different radiation sensor systems using optical fiber will be presented. Two are based on the increase of radiation induced attenuation of Ge P doped multimode graded index fibers, whereas the other two systems detect the Cerenkov light generated by relativistic electrons penetrating radiation hard fibers. The used fiber is an undoped multimode step index fiber with 300 mm core diameter. Dosimetry at high dose levels uses the radiation induced Bragg wavelength shift of Fiber Bragg Gratings. The selection of a suitable fiber for the individual application is an important requirement and depends on the type, doping, used wavelength and annealing behavior. In addition, the dose range, dose rate and temperature must be considered. After an extensive selection procedure, two types of fibers for the particular application were chosen. One is used as a dosimetry sensor for the slow local and distributed beam loss position monitor BLPM and the other for fast beam loss monitor BLM as well as beam profile monitors BPM . At six accelerators, all systems are used for in situ particle loss control by measuring the ionization dose and or Cerenkov light. These monitors provide a technique to improve the beam performance. This paper summarizes the basics of these measurement technologies and the experience at linear accelerators and at storage ring