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Owing to their ultra-high accelerating gradients, combined with injection inside micrometer-scale accelerating wakefield buckets, plasma-based accelerators hold great potential to drive a new generation of free-electron lasers (FELs). Indeed, the first demonstration of plasma-driven FEL gain was reported recently, representing a major milestone for the field. Several groups around the world are pursuing these novel light sources, with methodology varying in the use of wakefield driver (laser-driven or beam-driven), plasma structure, phase-space manipulation, beamline design, and undulator technology, among others. This paper presents our best attempt to provide a comprehensive overview of the global community efforts towards plasma-based FEL research and development.
Attempts to reduce high utilisation of psychiatric inpatient care by targeting the critical time of hospital discharge have been rare. In Germany, until now no such intervention has been implemented, let alone subjected to a clinical trial.
Method
“Effectiveness and Cost-Effectiveness of Needs-Oriented Discharge Planning and Monitoring for High Utilisers of Psychiatric Services” (NODPAM) is a multicentre RCT conducted in five psychiatric hospitals in Germany (Günzburg, Düsseldorf, Regensburg, Greifswald, and Ravensburg). Subjects asked to provide informed consent to participate have to be of adult age with a primary diagnosis of schizophrenia or affective disorder, and a defined high utilisation of psychiatric care during two years prior to the current admission. Subjects are asked to provide detailed outcome data at four measurement points during a period of 18 months. Recruitment (which started in April 06) is still ongoing. Thus, baseline data of about 350 participants will be presented.
Results
Recruitment has been quite successful and the study has been generally well accepted by participating patients and their clinicians in in- and outpatient treatment settings. Subjects showed substantial initial impairment on outcome measures (e.g. needs, psychopathology, quality of life, and level of functioning) and high utilisation of mental health care. Further results on conduct and feasibility of the trial will be presented.
Conclusions
The first phase of this mulicentre trial was promising. The potential of this study to strengthen the integration of mental health care provision in Germany will be discussed.
The metabolic syndrome is associated with an increased cardiovascular comorbidity and mortality. Many epidemiological studies prove an increased prevalence of the metabolic syndrome among psychiatric patients compared to the general population.
Methods:
In this on-going naturalistic observational study carried out in an inpatient treatment setting we as yet surveyed the parameters of the metabolic syndrome in 188 psychiatric patients at admission and at discharge. According to the NCEP definition at least three of the five following criteria have to be fulfilled for diagnosing the metabolic syndrome: visceral adipositas (waist circumference: male > 102 cm; female > 88 cm), diabetes mellitus (fasting glucose > 110 mg/dl), arterial hypertonia (≥130 mmHg systol., ≥ 85 mmHg diastol.), elevated triglycerides (≥ 150 mg/dl), reduced HDL cholesterol (male< 40 mg/dl; female< 50 mg/dl).
Results:
At discharge we found significantly more patients with visceral adipositas (p=0.0001) and elevated triglycerides (p=0.014) compared to the time of admission. A significantly higher percentage of female in comparison to male patients were diagnosed a metabolic syndrome. Higher age was associated with a higher prevalence of the metabolic syndrome (p=0.001, N=186).
Conclusions:
Our results demonstrate a deterioration of parameters of the metabolic syndrome in the course of an inpatient treatment. As visceral adipositas constitutes an essential risk factor for metabolic and cardiovascular diseases, an uncomplicated and easily manageable measurement of visceral body fat percentage would be desirable. In a pilot study we are evaluating the informative value of visceral body fat percentage as measured by a body composition analyzer.
It is well examined that hypothyroidism leads to cognitive losses and depressive moods. A well regulated thyroid metabolic status lowers those dysfunctions. After thyroid cancer and successful hormone replacement therapy cognitive and affective capacities can be re-established.
Objectives
Do female patients' results in cognitive and affective testing in hypothyroidism after thyroid cancer differ from the same patients' results in euthyroid?
Aims
We assume the hypothesis that there is an improvement in cognitive performance and the depressive mood in euthyroidism compared with earlier hypothyroidism.
Methods
In this study during 20 months N = 24 healthy female patients' hypothyroid metabolic statuses after thyroid cancer and thyreoidectomy were examined as an inpatient and within at least six months later as an outpatient in euthyroidism. At both examination dates the patients filled in the Beck Depression Inventory (BDI) and a psychometric test battery (Rey-Osterrieth Complex Figure Test, D2-Test).
Results
A Wilcoxon Signed-Rank Test indicate significant differences between hypothyroidism and euthyroid in favour of euthyroid in the BDI (M = z = – 3.56, p < .000), Rey-Osterrieth Complex Figures Test (cognitive reproduction, z = -4.20, p< .001) and the D2-Test (z = – 2.56, p = .011).
Conclusions
Our findings suggest that there is a relation between the hypothyroidism, depressive mood and fields of cognition (concentration and visual memory). It implies that a hormone replacement therapy should be initiated as quickly as possible for patients with hypothyroidism to re-establish their quality of life, performance and treatment compliance.
In schizophrenia negative symptoms often persist and determine an unfavourable course. Reviews including studies with small sample sizes indicate improvement of negative symptoms in schizophrenia patients by repetitive transcranial magnetic stimulation (rTMS), but provide heterogenous results. To prove the clinical efficacy of rTMS on negative symptoms trials with larger samples of patients are needed.
Methods
In a multicentre randomized, sham-controlled, rater- and patient-blind clinical trial including 197 patients we investigated the efficacy and tolerability of a 3 week 10 Hertz (Hz) rTMS add-on to antipsychotic therapy (in total 15000 stimuli, stimulation intensity 110 % of the individual motor threshold) over the left dorso-lateral prefrontal cortex (LDLPFC) immediately after treatment and during a 12 weeks follow-up.
Results
According to our primary outcome parameter we observed a significant decline in negative symptoms (negative sum score of the PANSS) in the verum and sham group (N = 124), but could not find a significant superior reduction in the verum group at day 21. At day 28 significant more patients in the verum compared to the sham group showed a clinical meaningful reduction of PANSS negative subscore (= 20 %) (N = 89; 57.5 % vs. 32.7 %, p = 0.033), however this effect did not persist at further follow-up.
Discussion
High-frequency (10 Hz) rTMS of LDLPFC over 3 weeks provided only a small benefit in the reduction of negative symptoms, however HF-rTMS was well tolerated. We discuss our results in comparison to current meta-analyses and previous studies.
Phased VLA observations of the Galactic center magnetar J1745-2900 over 8-12 GHz reveal rich single pulse behavior. The average profile is comprised of several distinct components and is fairly stable over day timescales and GHz frequencies. The average profile is dominated by the jitter of relatively narrow pulses. The pulses in each of the four profile components are uncorrelated in phase and amplitude, although the occurrence of pulse components 1 and 2 appear to be correlated. Using a collection of the brightest individual pulses, we verify that the index of the dispersion law is consistent with the expected cold plasma value of 2. The scattering time is weakly constrained, but consistent with previous measurements, while the dispersion measure DM = 1763+3−10 pc cm−3 is lower than previous measurements, which could be a result of time variability in the line-of-sight column density or changing pulse profile shape over time or frequency.
Two transfer functions for the unsteady lift response of an airfoil under attached flow conditions are experimentally investigated: the Theodorsen function for an airfoil oscillating in a constant free stream and the Sears function for a steady airfoil encountering a sinusoidal vertical gust. A two-dimensional airfoil with a Clark Y profile is submitted to two different unsteady excitations of distinct frequencies: a pitching oscillation around the leading edge and a sinusoidal vertical gust. The reduced frequency of the perturbation is in the range of $0.025<k<0.3$ and the Reynolds number of the undisturbed flow is in the range of $120\,000<\mathit{Re}<300\,000$. While the Theodorsen function is found to be a good estimator for the unsteady lift at moderate mean angles of attack, the Sears function does not capture the experimental transfer functions in frequency dependence or in limiting values. A second-order model provided by Atassi (J. Fluid Mech., vol. 141, 1984, pp. 109–122) agrees well with the experimental transfer function.
The Australian Square Kilometre Array Pathfinder (ASKAP) will give us an unprecedented opportunity to investigate the transient sky at radio wavelengths. In this paper we present VAST, an ASKAP survey for Variables and Slow Transients. VAST will exploit the wide-field survey capabilities of ASKAP to enable the discovery and investigation of variable and transient phenomena from the local to the cosmological, including flare stars, intermittent pulsars, X-ray binaries, magnetars, extreme scattering events, interstellar scintillation, radio supernovae, and orphan afterglows of gamma-ray bursts. In addition, it will allow us to probe unexplored regions of parameter space where new classes of transient sources may be detected. In this paper we review the known radio transient and variable populations and the current results from blind radio surveys. We outline a comprehensive program based on a multi-tiered survey strategy to characterise the radio transient sky through detection and monitoring of transient and variable sources on the ASKAP imaging timescales of 5 s and greater. We also present an analysis of the expected source populations that we will be able to detect with VAST.
We are developing a purely commensal survey experiment for fast (<5 s) transient radio sources. Short-timescale transients are associated with the most energetic and brightest single events in the Universe. Our objective is to cover the enormous volume of transients parameter space made available by ASKAP, with an unprecedented combination of sensitivity and field of view. Fast timescale transients open new vistas on the physics of high brightness temperature emission, extreme states of matter and the physics of strong gravitational fields. In addition, the detection of extragalactic objects affords us an entirely new and extremely sensitive probe on the huge reservoir of baryons present in the IGM. We outline here our approach to the considerable challenge involved in detecting fast transients, particularly the development of hardware fast enough to dedisperse and search the ASKAP data stream at or near real-time rates. Through CRAFT, ASKAP will provide the testbed of many of the key technologies and survey modes proposed for high time resolution science with the SKA.
The discovery of a pulsar (PSR) in orbit around a black hole (BH) is expected to provide a superb new probe of relativistic gravity and BH properties. Apart from a precise mass measurement for the BH, one could expect a clean verification of the dragging of space-time caused by the BH spin. In order to measure the quadrupole moment of the BH for testing the no-hair theorem of general relativity (GR), one has to hope for a sufficiently massive BH. In this respect, a PSR orbiting the super-massive BH in the center of our Galaxy would be the ultimate laboratory for gravity tests with PSRs. But even for gravity theories that predict the same properties for BHs as GR, a PSR-BH system would constitute an excellent test system, due to the high grade of asymmetry in the strong field properties of these two components. Here we highlight some of the potential gravity tests that one could expect from different PSR-BH systems, utilizing present and future radio telescopes, like FAST and SKA.
This paper summarizes how multi-wavelength measurements will be aggregated to determine Galactic structure in the interstellar medium (ISM) and produce the next-generation electron density model. Fluctuations in density and magnetic field from parsec scales down to about 1000 km cause a number of propagation effects in both radio waves and cosmic rays. Density microstructure appears to include Kolmogorov-like turbulence. The next generation electron-density model, NE2012, will include about double the number of lines of sight with dispersion and scattering measurements and it will be anchored with a much larger number of pulsar parallax distances. The foreground Galactic model is crucial for inferring similar ionized structures in the intergalactic medium (IGM) from scattering measurements on high-z objects. Intergalactic scattering is discussed with reference to distant sources of radio bursts. In particular, the cosmological radio scattering horizon is defined along with its analog for the ISM.
We report on new pulsars discovered in Arecibo drift-scan datA. Processing of 2200 deg2 of data has resulted in the detection of 41 known and 12 new pulsars. New pulsars include two millisecond pulsars, one solitary and one binary recycled pulsar, and one pulsar with very unusual pulse profile morphology and complex drifting subpulse behavior.
In a throwback to the early days in radio astronomy, new concepts for radio telescopes are being considered as next-generation facilities. The Low-Frequency Array (LOFAR) and the Square-Kilometer Array (SKA) are two particular projects that will incorporate innovations in hardware and software. Along the way to these projects, major surveys for pulsars and transients and/or follow-up pulsar timing observations will be conducted with the ALFA multibeam system at Arecibo, the Allen Telescope Array (ATA), the Extended VLA (EVLA) and with SKA prototype systems that include the European MBRACE project (Multibeam Radio Astronomy Concept Experiment) and China's FAST (500m Aperture Spherical Telescope). These projects are discussed here in the context of anticipated science drivers.
The first extrasolar planetary system was discovered around the pulsar PSR B1257+12, and the planets therein remain the lowest mass exoplanets known (with one whose mass is of order a lunar mass). Pulsar planetary systems will remain the only extrasolar planetary systems within which terrestrial-mass planets can be detected for the near future, and multiple pulsar planetary systems would provide strong circumstantial evidence that terrestrial-mass planets are ubiquitous, and possibly information about the formation of terrestrial-mass planets. We summarize two searches for planetary or proto-planetary systems around pulsars. The first is a series of infrared observations of millisecond pulsars in which the objective is to detect (proto-planetary) disks. The second uses a genetic algorithm—a function optimization method based on evolutionary processes in the natural world—to search for the signatures of planetary perturbations in pulse timing data.
We have studied the temporal behavior of linearly polarized position angle in a sample of 98 pulsars observed from Arecibo over a four–year period in a search for free precession and changes in interstellar magnetic fields along pulsar– earth lines of sight. We set upper limits on changes in position angle.
We have sampled the population of compact (θ ≤ 25") radio sources with spectral indices 1.5 ≤ α ≤ 3.2 (where Sv ∝ v—α) using two large scale radio surveys. This yields a statistically useful sample of 74 radio sources with S1.4GHz ≥ 2.5 mJy and S365MHZ ≥ 200 mJy. The majority of the sources appear to be extragalactic, resembling either high redshift radio galaxies or relic radio galaxies. However, six known pulsars were detected, as well as 16 sources of unknown nature that appear too small and have spectra too steep to be extragalactic. We are using VLBA, pulsar searching, optical/IR spectroscopy, and other techniques to definitively classify these sources. If any are new pulsars, they are potentially very interesting as they were missed by previous surveys.
Several studies in the last decade have explored dramatic instances of refractive fringing in dynamic spectra. We draw attention to a subtler but more widespread refractive effect: wisp-like structures extending (either linearly or with curvature) outward from the origin in the secondary spectrum plane. We have employed a simple pinhole screen simulation to investigate this phenomenon. It appears that the presence of one or more wisps in a secondary spectrum indicates a clump of scattering material that is significantly offset from the optical axis. Unlike the dramatic fringing events that have been investigated in the past, however, the interference that gives rise to a wisp is interference between rays within a scattering clump rather than between two major ray bundles. Furthermore, the scattering clump must be significantly elongated along the direction of pulsar motion. The range of fringe spacings that this produces, all with a similar slope in the secondary spectrum, gives rise to the linear extent of the wisp in the secondary spectrum.
The pulsar PSR 1641-45 was observed using the S2 VLBI Recording System at 1.6 GHz with radio telescopes at Tidbinbilla and Narrabri in Australia, and at Hartebeesthoek in South Africa. The data were correlated with the Canadian S2 VLBI Correlator using the ‘fast-dumping’ mode in conjunction with two independent pulsar gates. The high time and spectral resolution capabilities of this correlator permit a detailed examination of dispersion and dispersion-removal effects on individual pulses, and a comparison of these effects from pulse to pulse over the duration of the observation. We give a brief summary of the pulsar processing capabilities highlighted by examples from the PSR 1641-45 data.
We have developed a method for quantifying the flux variabilities of high energy gamma ray sources. We have applied this method to 128 sources listed in the second catalog of sources detected with the Energetic Gamma Ray Experiment Telescope (EGRET) (Thompson et. al. 1995). These sources include the Large Magellanic Cloud, 5 pulsars, 41 active galactic nuclei (AGN), and 81 sources not yet identified with known objects.
Our data include photon maps (E > 100 MeV) from 134 EGRET viewing periods spanning a roughly 3 year period. Each source was observed in 3-20 viewing periods ranging from a few days to 3 weeks in length. For each observation, a source flux was calculated using the method of maximum likelihood (Mattox et al. 1996) which simultaneously estimates the strength of the Galactic and isotropic diffuse emission, and that of a point source distributed as the EGRET point spread function.