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By employing Bayesian inference techniques, the full electron density profile from the plasma core to the edge of Wendelstein 7-X (W7-X) is inferred solely from neutral hydrogen beam and halo Balmer- α (H α) emission data. The halo is a cloud of neutrals forming in the vicinity of the injected neutral beam due to multiple charge exchange reactions. W7-X is equipped with several neutral hydrogen beam heating sources and an H α spectroscopy system that views these sources from different angles and penetration depths in the plasma. As the beam and halo emission form complex spectra for each spatial point that are non-linearly dependent on the plasma density profile and other parameters, a complete model from the neutral beam injection and halo formation through to the spectroscopic measurements is required. The model is used here to infer electron density profiles for a range of common W7-X plasma scenarios. The inferred profiles show good agreement with profiles determined by the Thomson scattering and interferometry diagnostics across a broad range of absolute densities without any changes to the input or fitting parameters. The time evolution of the density profile in a discharge with continuous core density peaking is successfully reconstructed, demonstrating sufficient spatial resolution to infer strongly shaped profiles. Furthermore, it is shown as a proof of concept that the model is also able to infer the main ion temperature profile using the same data set. [ABSTRACT FROM AUTHOR]

The 2018 operation phase (OP 1.2b) of the stellarator Wendelstein 7-X (W7-X) included, for the first time, neutral beam injection (NBI) to heat the plasma. Since the injection geometry at W7-X is not parallel, this generates both passing and trapped fast particles. During longer phases of NBI injection, with the primary purpose to study the heating efficiency of this system, Alfvén eigenmodes (AEs) were observed by a number of diagnostics, including the phase contrast imaging (PCI) system, the magnetic pick-up coils (Mirnov coils), and the soft x-ray multi-camera tomography system (XMCTS). Alfvén eigenmodes are of great interest for future fusion reactors as it has been shown that the resonant interaction of fast ions with self-excited AEs can lead to enhanced transport of fast ions and potentially to energy losses. This is especially true for so-called gap-modes, Alfvén eigenmodes with frequencies in gaps of the continuous spectrum, since they lack continuum damping. These modes are commonly known to be excited by fast ions, but other destabilizing mechanisms, e.g. the electron-pressure gradient are also possible. In this article we present a first analysis of the experimentally observed frequencies from the theoretical side. The calculation of shear Alfvén wave continua for selected cases and the assignment of observed frequencies to the gaps of the continuous spectra are presented. Using the ideal-MHD code CKA (Könies A. 2007 10th IAEA TM on Energetic Particles in Magnetic Confinement System), we find gap modes that match the experimental measurements in terms of the observed frequencies. We emphasize the crucial roles played by the coupling of sound and Alfvén waves as well as of the Doppler shift arising as a consequence of the radial electric field in W7-X. We employ the perturbative gyrokinetic code CKA-EUTERPE (Feh´er 2013 Simulation of the interaction between Alfv´en waves and fast particles), using a slowing-down distribution function for the fast ions as calculated by the Monte-Carlo particle following code ASCOT (Hirvijoki et al 2014 Comput. Phys. Commun. 185 1310–21) to assess the fast-ion drive. We find that the fast-ion drive is insufficient to overcome the background-plasma damping. The fact that unstable modes were observed experimentally may point to problems with the modelling or indicate the existence of other destabilizing mechanisms, e.g. associated with the electron-pressure gradient (Windisch et al 2017 Plasma Phys. Control. Fusion 59 105002) that sensitively depend on the profiles of the background plasma. [ABSTRACT FROM AUTHOR]

The Charge Exchange Recombination Spectroscopy (CXRS) diagnostic has become a routine diagnostic on almost all major high temperature fusion experimental devices. For the optimized stellarator Wendelstein 7-X (W7-X), a highly flexible and extensive CXRS diagnostic has been built to provide high-resolution local measurements of several important plasma parameters using the recently commissioned neutral beam heating. This paper outlines the design specifics of the W7-X CXRS system and gives examples of the initial results obtained, including typical ion temperature profiles for several common heating scenarios, toroidal flow and radial electric field derived from velocity measurements, beam attenuation via beam emission spectra, and normalized impurity density profiles under some typical plasma conditions. [ABSTRACT FROM AUTHOR]

Human-wildlife conflict is detrimental to the conservation of threatened carnivores and the livelihoods of rural communities. This paper compares perceived levels of human-carnivore conflict experienced on five Namibian communal conservancies and four resettled farming areas. Factors explored include how reported depredation was affected by livestock husbandry practices, the perceived annual cost of depredation and the reported problem predator species. Of the 147 respondents interviewed, perceived depredation was greater than in previous studies; high perceived depredation was associated with greater rates of predator removal, increased ranking of predators as problems and increased predator sighting frequency. Small stock species were the most commonly depredated livestock. The most frequently perceived predators were: jackals on goats and sheep, wild cats on chickens, leopards on horses and spotted hyenas on cattle. The financial cost of this predation was US$508898, mostly attributable to cattle depredation, and agricultural training schemes recommending good livestock management may help reduce this cost. A move from small to large stock farming could be promoted in areas with an abundance of small- to medium-sized carnivores and a lack of large carnivores. Further incentives, such as meat provision and income from consumptive and non-consumptive tourism could ensure benefits outweigh costs of wildlife coexistence. [ABSTRACT FROM PUBLISHER]

PURPOSE: A stapled pouch-anal anastomosis without mucosectomy is widely used in restorative proctocolectomy. Uncertainty exists about the longer-term outcome of retaining a columnar cuff of epithelium in the anal canal and about the need for surveillance of the columnar cuff, The aim of this article was to assess the ability to obtain biopsies of the columnar cuff, to assess the risk of dysplasia. and to search for the presence of aneuploidy as an early of marker of dysplasia in nondysplastic epithelium. METHOD: A total of 457 biopsy specimens were taken during 203 examinations of 113 patients. All biopsy specimens were stained with hematoxylin and eosin and examined by microscopy. One hundred thirty-two of these biopsy specimens from 67 patients were frozen and analyzed by flow cytometry for aneuploidy. RESULTS: Mean follow up after pouch formation was 2.5 years, and the time after diagnosis of ulcerative colitis was 10.1 years. Successful columnar cuff biopsies were done on 93 percent of patients. There was no dysplasia. Two biopsy specimens from one patient had aneuploidy. CONCLUSION: To date, neoplastic change in the columnar cuff is rare. A selective policy of surveillance biopsies is recommended that includes patients greater than ten years after the diagnosis of ulcerative colitis and patients with dysplasia or cancer in their proctocolectomy specimen, but long-term follow-up data arc needed. [ABSTRACT FROM AUTHOR]

Properties of levels up to 5 MeV excitation inCl were studied withCl( p, p′ γ)Cl,Cl( α, α′ γ)Cl andS( α, pγ)Cl reactions. Results are discussed with reference to the many-particle shell model with an effective surface delta interaction. [ABSTRACT FROM AUTHOR]

The spins and electromagnetic properties of low-lying levels inK with excitation energy ≦4.127 MeV were studied with theK( p, p′γ)K and theAr( α, pγ)K reactions. Experimental results are discussed in terms of shell model calculations with a modified effective surface delta interaction. [ABSTRACT FROM AUTHOR]

The spins and electromagnetic properties of levels inSc up to 2,352 keV were studied by means of inelastic proton scattering using a 3-parameter coincidence arrangement and Coulomb excitation withHe andHe beams. Relevant experimental results are discussed in terms of the Thankappen-True core-plus-particle model. [ABSTRACT FROM AUTHOR]

Levels up to 3,016 keV inCo were studied using theCo ( p, p′y) andFe ( α, py) reactions. Level energies, branching ratios, mean lifetimes and spins were obtained for a number of levels. [ABSTRACT FROM AUTHOR]

The spins and electromagnetic properties of levels up to 3,700 keV inV were studied by means of inelastic proton scattering. Results are discussed with reference to the many-particle shell model using effective surface delta and realistic Kuo-Brown interactions. [ABSTRACT FROM AUTHOR]

The lifetime of the fourth excited state ofSc, at an energy of 720 keV, was determined in a nuclear resonant scattering experiment. Gamma rays of the desired energy for the excitation of this level were obtained by Compton scattering of the 1173 and 1332 keV photons from a 4300 Ci radioactiveCo source. A value of (5.6±1.2) meV was found for the radiation width of the level, assuming a value of 5/2 for its spin. The corresponding mean lifetime is (0.12) ps. An attempt was made to determine the spin of the level by means of angular distribution measurements. [ABSTRACT FROM AUTHOR]