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The dark matter annihilation cross section can be amplified by orders of magnitude if the annihilation occurs into a narrow resonance, or if the dark-matter particles experience a long-range force before annihilation (Sommerfeld effect). We show that when both enhancements are present they factorize completely, that is, all long-distance non-factorizable effects cancel at leading order in the small-velocity and narrow-width expansion. We then investigate the viability of ``super-resonant'' annihilation from the coaction of both mechanisms in Standard Model Higgs portal and simplified MSSM-inspired dark-matter scenarios., Comment: 15 pages, 4 figures

Superconducting Undulators (SCUs) can produce higher photon flux and cover a wider photon energy range compared to permanent magnet undulators (PMUs) with the same vacuum gap and period length.To build the know-how to implement superconducting undulators for future upgrades of the European XFEL facility, the test stand SUNDAE1 for the characterization of SCU is being developed. The purpose of SUNDAE1 is the training, tuning and development of new SCU coils by means of precise magnetic field measurements.The experimental setup will allow the characterization of magnets up to 2m in length. These magnets will be immersed in a Helium bath at 4K or 2K temperature.In this article, we describe the experimental setup and highlight its expected performances.

Wear resistant ceramic coatings were generated on novel commercially pure titanium grade 4+ alloys by the plasma electrolytic oxidation technique (PEO) in an aluminate and zirconia containing electrolyte. The coatings were obtained adopting a full regular two-level factorial design of experiments (DoE) varying the PEO process parameters current density, repetition rate and duty cycle. The generated coatings were characterized with respect to its wear resistance and mechanical properties by reciprocal ball-on-flat tests and nanoindentation measurements. Thickness, morphology and phase formation of the PEO coatings was analyzed by scanning electron microscopy (SEM/EDS) and X-ray diffraction. XRD results indicate the formation of crystalline aluminium titanate (TiAl2O5) as well as t-ZrO2 and alumina leading to an increase in hardness and wear resistance of the PEO coatings. Evaluation of the DoE’s parameter interaction shows that the main effects for generating wear resistant coatings are current density and repetition rate. In particular, the formation of mechanically stable and adhesive corundum and zirconia containing coatings with increasing current density and frequency turned out to be responsible for the improvement of the tribological properties. Overall, the PEO processing significantly improves the wear resistance of the CP titanium base alloy.

Hydroxyapatite-containing titanium oxide coatings were generated on novel CP-Ti grade 4+ alloys by plasma electrolytic oxidation (PEO) process in two Ca- and P-containing electrolytes. The coatings were obtained under direct current (DC) mode and unipolar pulsed mode at 10 Hz. The effect of the electrolyte composition and the electrical parameters on the coating's performance was investigated. The coatings were characterized with respect to morphology, thickness, and phase formation by scanning electron microscopy (SEM/EDX) and X-ray diffraction. In both electrolytes hydroxyapatite-rich titania coatings could be formed in-situ. The amount of generated hydroxyapatite and perovskite phase depends on the electrolyte composition as well as on the electrical parameters. The coating's corrosion performance was tested in pH 7.0 Hank's solution + 0.1 M H2O2 by open circuit potential (OCP) measurements, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Corrosion resistance of coatings generated under unipolar pulsing is increased significantly. Equivalent circuit modelling of EIS spectra indicates a hierarchical PEO coating structure revealing that the enhanced corrosion resistance originates mainly from the inner barrier layer.

Titania coatings were produced on Ti 13Zr 13Nb by a unipolar pulsed DC plasma electrolytic oxidation (PEO) process in an electrolyte containing 1 M H2SO4 + 0.1 M H3PO4. The samples were galvanostatically anodized under a constant charge-carrier density of 63 C cm− 2 and current-densities reaching from 14 mA cm− 2 up to 700 mA cm− 2. Both a constant current mode and a unipolar pulsed mode with a duty-cycle of 50% and frequencies of 1 Hz to 50 Hz were performed. The surface layers were characterized by scanning electron microscopy (SEM/EDX), X-ray diffraction (XRD) and nanoindentation. Titanium oxide coatings with a thickness of several micrometers and a porous structure could be generated. The coatings morphology was evaluated. It can be shown that the porosity can be reduced with increasing frequency. The coatings consist of anatase and rutile, the phase composition of the coatings can be adjusted by the PEO current density. The corrosion resistance of the layers was tested in a simulated body fluid (SBF) with the addition of 0.1 M H2O2 by open circuit potential measurements, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). EIS data fitting indicates a composed layer structure of an outer porous layer and an inner barrier layer. Higher current densities during the PEO process formed thicker coatings, which consequently resulted in lower corrosion currents. The addition of zirconia nanoparticles into the electrolyte increased the surface hardness to an average value of 12.8 GPa, compared to that of an untreated sample (4.1 GPa) and PEO samples without particle addition (8.5 GPa).

Nature photonics 14(6), 391 - 397 (2020). doi:10.1038/s41566-020-0607-z, The European XFEL is a hard X-ray free-electron laser (FEL) based on a high-electron-energy superconducting linear accelerator. The superconducting technology allows for the acceleration of many electron bunches within one radio-frequency pulse of the accelerating voltage and, in turn, for the generation of a large number of hard X-ray pulses. We report on the performance of the European XFEL accelerator with up to 5,000 electron bunches per second and demonstrating a full energy of 17.5 GeV. Feedback mechanisms enable stabilization of the electron beam delivery at the FEL undulator in space and time. The measured FEL gain curve at 9.3 keV is in good agreement with predictions for saturated FEL radiation. Hard X-ray lasing was achieved between 7 keV and 14 keV with pulse energies of up to 2.0 mJ. Using the high repetition rate, an FEL beam with 6 W average power was created., Published by Nature Publ. Group, London [u.a.]

Polycrystalline alumina samples ( α -Al 2 O 3 , purity: 99.8%) were irradiated by 63 Cu heavy ions ( E = 0.5 MeV/u) at various fluences. After irradiation, absorption measurements were performed within the wavelength range from 200 to 1000 nm to evaluate color center evolution. Thermal annealing behavior of the created defects was investigated with respect to annealing temperature and duration. Complex color center formation processes depending on particle fluence and temperature could be observed. Calculated activation energies necessary for F- and F + -center migration are ∼0.3 eV for temperatures ranging from RT to ∼673 K.

Inorganic scintillation screens were irradiated with swift heavy ion beams at GSI accelator facility, using protons up to Uranium ions as projectiles. Beams were extracted from the synchrotron SIS18 with high energy (≈300 MeV/u) in slow and fast extraction mode. During irradiation the scintillation response of the screens was recorded by two different optical setups simultaneously to investigate the light output, profile characteristics and emission spectra. In principle fast extracted beams induce lower light output than slow extracted beams. The output per deposited energy shows a decreasing dependency with respect of the atomic number. Emission spectra showed no significant defects of the materials, neither at irradiation with increasing beam intensity nor during long time irradiation.

Polycrystalline alumina samples ( α -Al 2 O 3 , purity: 99.8%) were irradiated with 63 Cu 5 + ions of 32 MeV kinetic energy (≈0.5 MeV/u) up to fluences of 10 14 ions/cm 2 at various temperatures ranging from 295 to 973 K. Ion beam induced luminescence and emission spectra were monitored at wavelengths from 320 to 800 nm. Optical absorption measurements were performed to deduce color center formation. Results were evaluated by the Birks model to determine the material’s radiation hardness. The applicability of alumina as scintillation screens for ion beam diagnostics could be extended by enhanced temperature operation. Analysis of the emission spectra shows a complex color center formation behavior as a function of fluence and temperature.

This article makes an argument for the importance of annotating Bessie Head's most famous novel A Question of Power. It briefly discusses some of the more general issues in annotation, such as problems of interpretation, availability of different editions, and relevance of other materials. The article makes the argument that since so much of Head's writing and philosophy involves uncertainty and open-endedness, it is important to make as much information as possible available to readers of the novel in order for them to understand what happened in Head's own life and to recognize how she used that material in her work to create meaning. The article concludes with the suggestion, in the spirit of Head herself, that perhaps the novel can never be ‘fully’ annotated.

Zwei Epi so den ei ner aku ten He pa ti tis C mit un ter schied li chen Ge no ty pen bei ei nem auf Peg in ter fe ron-Mo no the ra pie an spre chen den Dia ly se pa tien ten Wir be rich ten uber den Fall ei nes 63-jah ri gen Lang zeit dia ly se pa tien ten, der zwei auf ein and er fol gen de Epi so den ei ner He pa ti tis C-Vi rus-In fek tion mit un ter schied li chen Ge no ty pen er litt und in bei den Fal len er folg reich durch eine Mo no the ra pie mit pe gy lier tem IFN-a be han delt wer den konn te.

(2009). Contested Identities: Bessie Head, Maru, and BaSarwa/San: A Report from the Home Front. Journal of the African Literature Association: Vol. 4, No. 1, pp. 158-180.

We report the case of a 63-year-old male patient on long-term hemodialysis who suffered two consecutive episodes of persistent hepatitis C virus infection with different genotypes and was successfully treated with pegylated IFN-alpha monotherapy each time.

Electron loss and electron emission for grazing impact of noble gas atoms with energies in the keV domain are investigated via time-of-flight spectra recorded in coincidence with the number of emitted electrons. The data is analyzed in terms of computer simulations concerning the interaction of the fast atoms with the electron gas in the selvedge of the Al(1 1 1) surface. The interaction is approximated by binary collisions of the fast atoms with Fermi electrons of the conduction band and differential cross sections obtained for electron scattering from free atoms. For an effective number of collisions of about 50 the energy loss spectra are fairly well reproduced by our calculations. We show that for our conditions the shift of the energy spectra for the emission of an additional electron from the surface is close to the work function of the target.

Kinetic electron emission (KE) for grazing scattering of H, He, Ne, and Ar ground state atoms with keV/amu impact energies on clean monocrystalline atomically flat Al and Cu surfaces has been studied in coincidence with projectile energy loss. Measured KE yields are subject to a clear impact energy threshold, in agreement with a free electron gas model description for the target electron momentum distribution (“classical” KE threshold). For smaller projectile scattering angles corresponding to larger distances of closest approach to the surface, this classical KE threshold is shifted to higher impact energies. By measuring KE threshold energies for different projectile scattering angles, we have probed the effective electron surface potential. For scattering of Ne and Ar atoms, a very weak electron emission is observed below the classical KE threshold, which within a more realistic description of the electron momentum distribution for the target surface can be ascribed to higher electron momenta. Grazing projectile scattering also permits a practically non-destructive surface structure determination, because a considerably larger number of electrons is emitted when changing from planar to axial surface scattering “surface triangulation”.

The energy loss of hydrogen atoms with energies of 400 eV and 1 keV is studied in coincidence with the number of emitted electrons during grazing scattering from atomically clean and flat KI(001) and LiF(001) surfaces. The energy loss spectra for specific numbers of emitted electrons are analyzed in terms of a binary interaction model based on the formation of transient negative ions via local capture of valence band electrons from anion sites. Based on computer simulations we derive for this interaction scenario probabilities for the production of surface excitons, for electron loss to the conduction band of KI, for emission of electrons, and for formation of negative hydrogen ions. The pronounced differences of data obtained for the two surfaces are attributed to the different electronic structures of KI and LiF.

Kinetic emission (KE) of electrons near its threshold is studied for grazing impact of keV He atoms on flat and clean Al(111), Al(110), and Cu(111) surfaces. We observe a defined dependence of the KE threshold behaviour on the scattering conditions. The data are analyzed in the framework of a classical model for electron emission based on momentum transfer in binary encounters between atomic projectiles and conduction electrons of the metal target. From the impact velocity dependence of KE yields near threshold we obtain information on momenta of Fermi electrons as a function of distance from the surface and on the corresponding electronic surface potential.

The energy loss of He atoms with energies E ⩽ 28 keV scattered from Al(1 1 1) under a grazing angle of incidence is recorded in coincidence with the number of electrons emitted in the collision. From our data we deduce the mean energies for emission of a specific number of electrons during impact of the atomic projectiles. We observe that only a fraction of some percent of the energy transferred to metal electrons results in their emission. The mean energy for emission of electrons in head-on binary collisions of He atoms with conduction electrons is estimated from a simple classical model which describes the data fairly well. For higher energies of the projectile motion with respect to the surface normal, i.e. collisions with surface atoms under smaller impact parameters, the mean energy transfer to emitted electrons is enhanced which is attributed to an electron promotion mechanism.

In grazing collisions of atoms and ions with monocrystalline surfaces, projectiles are scattered along defined trajectories, and electron emission therefore proceeds under well characterised conditions compared to large-angle impact on polycrystalline target surfaces. Total electron yields can be measured in coincidence with energy loss of scattered projectiles, down to 10-4 electrons per projectile near the threshold for kinetic electron emission. In the present comment we demonstrate the recent experimental progress for grazing scattering of slow (>100 eV up to some keV per amu) atoms and multiply charged ions on metal (Au, Al) and insulator (LiF) surfaces. Observed kinetic and potential electron emission processes can be quantitatively explained in terms of simple model assumptions. These experiments are carried out in a practically non-destructive manner with intriguing aspects for novel surface-analytical applications.

We present an analysis of data obtained in coincident studies on projectile energy loss and number distributions of emitted electrons for scattering of hydrogen atoms from an atomically clean and flat LiF(0 0 1) surface. The emission of electrons, production of surface excitons and formation of negative ions is explained by a model of electron capture by projectiles at fluorine lattice sites where the formation of negative hydrogen ions is the common precursor for the electronic processes of relevance here. We describe the interactions in terms of concepts for gas phase collisions and derive probabilities for the detachment of negative ions during the collision with the insulator surface.

In coincident studies on projectile energy loss and number distributions of emitted electrons for scattering of hydrogen atoms from an atomically clean and flat LiF(0 0 1) surface we derive probabilities for emission of electrons and production of surface excitons near their respective kinematic thresholds. We analyze our data in terms of electron transfer in binary atomic collisions with one collision partner being embedded at the anion site of an ionic crystal and derive information on the energy defects in these collisions.

The energy loss of kilo-electronvolt hydrogen atoms for scattering from a LiF(001) surface under a grazing angle of incidence is measured in coincidence with the number of emitted electrons. The combined time-of-flight and electron number distributions show discrete features which are attributed to specific numbers for emitted electrons and production of surface excitons. The distributions are fairly well reproduced in terms of binomial distributions. The corresponding probabilities for electron and exciton production can consistently be related to a model where the formation of negative hydrogen atoms via local electron capture from halogen lattice sites is considered as a precursor for both processes.

Neutral hydrogen atoms with energies ranging from 300 eV to 1.5 keV are scattered from a clean and flat LiF(0 0 1) surface under grazing angles of incidence. By detection of time-of-flight spectra in coincidence with the number of emitted electrons, we study electron emission and excitation phenomena near their respective thresholds. We find in this energy regime population of surface excitons as dominant inelastic interaction channel. The data are consistently interpreted in the framework of a binary collision model where the formation of negative hydrogen ions is the common precursor of electronic excitation of the target and electron emission.

Neutral hydrogen atoms with energies ranging from about 1 to 20 keV are scattered from a clean and flat LiF(0 0 1) surface under grazing angles of incidence. By detection of time-of-flight (TOF) spectra in coincidence with the signal of an electron number detector, we study electron emission and excitation phenomena. We present recent progress in an on-line processing of spectra by means of a double coincidence unit.

In den neuen Bundeslaendern wurde nach der Wiedervereinigung rasch die flaechendeckende Luftrettung nach westdeutschem Vorbild aufgebaut, um dem dramatischen Anstieg (um das 2,4fache) der Zahl der Getoeteten im Strassenverkehr zu begegnen. In der vorliegenden Studie wurde die Effizienz der neuen RTH (Rettungshubschrauber)-Stationen anhand der Zahl und Qualitaet der Traumaeinsaetze im Vergleich mit zwei etablierten westdeutschen Stationen (Hannover und Ulm) analysiert. Als Score fuer die Schwere der Traumaeinsaetze wurde der einfache NACA-Score verwendet, der bei einem groesseren Patientenkollektiv (n = 21) gut mit dem aufwendigen Injury Severity Score korrelierte. Im Zeitraum 1993 bis 1997 kam es bei den ostdeutschen Stationen zu einem Anstieg der durchschnittlichen Einsatzzahl/Jahr um 60,3 Prozent bei leicht sinkendem Anteil an Unfalleinsaetzen (von 43,5 Prozent auf 38,8 Prozent). Die Anzahl an Fehleinsaetzen lag 1997 im Vergleich zu den westdeutschen Stationen offenbar aufgrund haeufig verzoegerter Alarmierung sehr niedrig (76 versus 184). Auch 1997 wurden noch zwei Drittel aller Einsaetze durch nur eine Leitstelle (Standortleitstelle) veranlasst. Die Anzahl der schweren Traumaeinsaetze mit einem NACA-Score 4 bis 6, bei denen spezifische Vorteile der Luftrettung zum Tragen kommen, ist 1997 trotz 1,7fach hoeherer Letalitaet im Strassenverkehr bei den ostdeutschen Stuetzpunkten wesentlich niedriger als bei den westdeutschen RTH-Stationen (102 versus 207). Eine Ursache ist offenbar das niedrige Anforderungsniveau bei schweren Unfallereignissen ausserhalb des Einzugsbereichs der Standortleitstelle. Die Ergebnisse zeigen, dass eine verbesserte Integration der ostdeutschen RTH in die Versorgung schwerer Unfallereignisse dringend erforderlich ist. (A) Titel in Englisch: Development of the newly established air medical service in Eastern Germany 1993-97 - Comparison with two established West German air ambulances.

Grundlagen: Die aszendierende Cholangitis stellt eine mogliche Komplikation nach biliodigestiven Anastomosen dar. In diesem Versuchsvorhaben sollten 3 verschiedene operative Techniken mit bakteriologischen Untersuchungen der Gallenwege und des oberen Gastrointestinaltraktes verglichen und die Frage pathologischer Fehlbesiedelung geklart werden.

Tick-borne encephalitis virus (TBEV) is the aetiological agent of tick-borne encephalitis (TBE), a potentially fatal central nervous system infection of humans. TBE is endemic in many areas of Europe and Asia; however, very scarce data on TBEV activity are available from Turkey. We aimed to identify TBEV exposure in healthy blood donors and the impact of TBEV in central nervous system infections in Central/Northern Anatolia. Two-thousand four hundred and fifty four sera, collected from blood donors at Ankara, Konya, Eskişehir and Zonguldak branches of the Turkish Red Crescent Middle Anatolia Regional Blood Center, were analysed for TBEV serosurveillance. Paired serum and cerebrospinal fluid samples from 108 patients with the diagnosis of aseptic meningitis/encephalitis of unknown aetiology were also evaluated to identify TBE and neuroborreliosis cases. Commercial enzyme-linked immunosorbent assays and indirect immunofluorescence tests were employed for antibody detection. Forty-seven donor samples (1.9%) were reactive for TBEV IgG. In 25 persons with IgG reactivity (53.1%), risk factors for tick-borne infections were revealed. One sample from Zonguldak province (1/198; 0.5%) in the Black Sea region of Turkey was confirmed to possess neutralizing antibodies via plaque reduction neutralization test. TBEV IgM was detected in 9.2% (8/108) of the patients. IgM was accompanied by IgG reactivity in two persons where, in one, recent history of a tick bite was also identified. Intrathecal antibody production for TBEV could not be demonstrated. No evidence for Borrelia infections could be found. Confirmed exposure to TBEV and/or an antigenically similar tick-borne flavivirus is documented for the first time in blood donors in Zonguldak in Northern Anatolia. Probable cases of TBE have also been identified from Central Anatolia. The epidemiology of TBEV activity in Turkey needs to be assessed and benefits of vaccination for general population, risk groups or travellers must be considered.

The use of a daily diary to assess the range and frequency of anxious events in young children was examined. The results indicated that although further modifications in procedure may be necessary to address the child's maturational age, self-monitoring is a feasible assessment strategy for use with anxious children. Furthermore, the findings that anxious children report significantly more emotional distress and more negative behaviors such as crying, somatic complaints or behavioral avoidance provide some initial validity for the use of this assessment format. The results are discussed in terms of the utility and validity of a diary format and its ability to enhance our clinical understanding of childhood anxiety disorders.

Electron emission from LiF, KCl, and KI crystal surfaces during grazing collisions of swift protons is studied using a first-order distorted-wave formalism. Owing to the localized character of the electronic structure of these surfaces, we propose a model that allows us to describe the process as a sequence of atomic transitions from different target ions. Experimental results are presented for electron emission from LiF and KI and energy loss from KI surfaces. Calculations show reasonable agreement with these experimental data. The role played by the charge of the incident particle is also investigated.

A new L-band photoelectron gun (prototype 3.2) has been installed for use with a 10 MW klystron at the Photo- Injector Test facility in Zeuthen (PITZ). This gun has been conditioned starting in April 2007 up to a maximum gradient of about 60 MV/m. The gun was tuned for resonance at 1.3 GHz, and stable operation has been achieved with 100 mus RF pulses with a repetition rate of 10 Hz. Over certain periods the gun has been conditioned at high gradient with RF pulses of 400 mus, and conditioning has to be continued at longer pulse lengths up to 700 mus. Maximum power in the gun has been achieved with a new RF waveguide phase shifter with a 2pi range. Dark current measurements have been performed with several cathodes, including uncoated molybdenum, electropolished uncoated molybdenum, and cesium telluride. Also, the first photoelectrons have been accelerated with the new gun cavity.

Dislocated fractures of the femoral head are highly infrequent injuries. In line with this multicenter study, a follow-up examination of patients with Pipkin fractures was performed in Austrian trauma centers. The aim of this study was to evaluate the types of fractures, the kind of treatment, and the long-term results.In sum 46 patients were included in our study. A personal and radiological follow-up examination was carried out. The fractures were classified according to Pipkin.Patients with type I fractures had the best functional outcome according to the Harris Hip Score, followed by patients with type II fractures, type IV fractures, and finally type III fractures. The result of the radiological follow-up examination showed that patients who were treated conservatively or with extirpation of the fragment had a lower grade of arthrosis. The poorest radiological outcome was seen in patients who underwent surgical treatment with open reduction and internal fixation. The implantation of a total hip prosthesis was necessary in 24% of the patients. A relevant soft tissue calcification was not recorded.The size and location of the fractured fragment has a huge influence on the outcome. An exact anatomical reconstruction of the femoral head, especially of the weight-bearing part, is absolutely necessary.

Follow-up of patients with pelvic ring fractures and associated injuries of the lower urogenital tract was performed from January 2000 to October 2004. Analysis focused on incidence, fracture type, type of urogenital injury, associated intrapelvic lesions, mortality, and urologic outcome.The retrospective study included 18 of 111 patients (16.2%). Nine patients had a rupture of the urethra, six a rupture of the bladder, three a rupture of the penile root, and two a gonadal defect. The type of the pelvic ring fracture according to the AO classification was type A in 1, type B in 6, and type C in 11 cases. Fifteen patients (83.3%) were followed up clinically for a mean duration of 26 months (range: 12-66 months) after trauma. Seven patients were asymptomatic concerning the urogenital injury, five had erectile dysfunction, two had urethral stenosis, in one case associated with incontinence, and one patient with bilateral defect of the testicles was under hormone substitution therapy.Urogenital injuries, often associated with intrapelvic lesions in so-called complex pelvic trauma, are typical for high-grade pelvic ring fractures and have an essential prognostic value for the patient's morbidity and quality of life.

The energy loss of $100\text{\ensuremath{-}}\mathrm{keV}$ hydrogen atoms scattered under a grazing angle of incidence from a clean and flat Cu(111) surface is studied in coincidence with the number of emitted electrons. From the dependence of the energy loss on the angle of incidence we deduce the position dependent stopping power which shows the same functional dependence but a factor of about 2 higher values than recent calculations. From the number of emitted electrons related to a specific energy loss we reveal processes related to electron emission as dominant channel for energy dissipation of scattered projectiles.