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7Be(p, $\gamma$ )8B has an important role in nuclear astrophysics, having a direct impact on both the high energy component of solar neutrinos and the 7Li abundance after the Big Bang Nucleosynthesis. All direct measurements providing useful information on this reaction so far used the same approach, i.e. a proton beam on a radioactive 7Be target. The overall precision and accuracy of the estimate of the astrophysical rate of this reaction are limited by the discrepancy between the results of existing measurements, possibly due to the complicated stoichiometry and beam induced deterioration of the radioactive targets. The ERNA (European Recoil separator for Nuclear Astrophysics) collaboration planned a new experiment in inverse kinematics exploiting the intense 7Be beam available at CIRCE (Center for Isotopic Research on Cultural and Environmental heritage), Caserta, Italy. The 8B recoils are produced in a windowless hydrogen gas target and detected after the efficient mass separation provided by ERNA. Here we present the commissioning of the experimental setup and a first cross section measurement at $E_{\mathrm{cm}}\approx 812$ keV.

Background: The origin of fluorine is a widely debated issue. Nevertheless, the $^{15}\mathrm{N}(\ensuremath{\alpha},\ensuremath{\gamma})^{19}\mathrm{F}$ reaction is a common feature among the various production channels so far proposed. Its reaction rate at relevant temperatures is determined by a number of narrow resonances together with the direct capture and the tails of the two broad resonances at ${E}_{\mathrm{c}.\mathrm{m}.}=1323$ and 1487 keV.Purpose: The broad resonances widths, ${\mathrm{\ensuremath{\Gamma}}}_{\ensuremath{\gamma}}$ and ${\mathrm{\ensuremath{\Gamma}}}_{\ensuremath{\alpha}}$, have to be measured with adequate precision in order to better determine their contribution to the $^{15}\mathrm{N}(\ensuremath{\alpha},\ensuremath{\gamma})^{19}\mathrm{F}$ stellar reaction rate.Methods: Measurement through the direct detection of the $^{19}\mathrm{F}$ recoil ions with the European Recoil separator for Nuclear Astrophysics (ERNA) were performed. The reaction was initiated by a $^{15}\mathrm{N}$ beam impinging onto a $^{4}\mathrm{He}$ windowless gas target. The observed yield of the resonances at ${E}_{\mathrm{c}.\mathrm{m}.}=1323$ and 1487 keV is used to determine their widths in the $\ensuremath{\alpha}$ and $\ensuremath{\gamma}$ channels.Results: We show that a direct measurement of the cross section of the $^{15}\mathrm{N}(\ensuremath{\alpha},\ensuremath{\gamma})^{19}\mathrm{F}$ reaction can be successfully obtained with the recoil separator ERNA, and the widths ${\mathrm{\ensuremath{\Gamma}}}_{\ensuremath{\gamma}}$ and ${\mathrm{\ensuremath{\Gamma}}}_{\ensuremath{\alpha}}$ of the two broad resonances have been determined. While a fair agreement is found with earlier determination of the widths of the 1487 keV resonance, a significant difference is found for the 1323 keV resonance ${\mathrm{\ensuremath{\Gamma}}}_{\ensuremath{\alpha}}$.Conclusions: The revision of the widths of the two more relevant broad resonances in the $^{15}\mathrm{N}(\ensuremath{\alpha},\ensuremath{\gamma})^{19}\mathrm{F}$ reaction presented in this work is the first step toward a more firm determination of the reaction rate. At present, the residual uncertainty at the temperatures of the $^{19}\mathrm{F}$ stellar nucleosynthesis is dominated by the uncertainties affecting the direct capture component and the 364 keV narrow resonance, both so far investigated only through indirect experiments.

The astrophysical S-factor of 14N(p,gamma)15O has been measured for effective center-of-mass energies between E_eff = 119 and 367 keV at the LUNA facility using TiN solid targets and Ge detectors. The data are in good agreement with previous and recent work at overlapping energies. R-matrix analysis reveals that due to the complex level structure of 15O the extrapolated S(0) value is model dependent and calls for additional experimental efforts to reduce the present uncertainty in S(0) to a level of a few percent as required by astrophysical calculations., Comment: Eur. Phys. J. A, accepted. 17 pages, 15 figures

For improved cross-section measurements of the reaction 12C(α,γ)16O in inverted kinematics, a recoil separator ERNA is developed at the 4MV Dynamitron tandem accelerator in Bochum to detect directly the 16O recoils with high efficiency. Due to the emission of the capture γ-rays, the kinematically forward directed 16O recoils are described by an angle and energy spread. Thus, the acceptances in angle and energy of ERNA must cover these spreads in order to extract reliable cross-section values. We report on such acceptance measurements over the energy range Ecm=0.7-5.0 MeV, using an 16O pilot beam. © 2003 Elsevier B.V. All rights reserved.

Non-radiative transitions in nuclear capture reactions between light nuclei play a relevant role in stellar nuclear astrophysics, where nuclear processes occur at typical energies from tens to hundreds of keV. At higher energies, instead, the E0 contributions may be shadowed by more intense transitions. The experimental study of E0 transitions requires a specific detection setup, able to uniquely identify events where an electron-positron pair is produced. A compact ΔE-E charged-particle spectrometer based on two silicon detectors has been designed to be installed in the jet gas target chamber of the recoil mass separator ERNA (European Recoil separator for Nuclear Astrophysics) at the CIRCE laboratory of Caserta, Italy. The detector design, its performances and the first foreseen applications are described.

Stellar models show an exceptional sensitivity on the cross section of 12C( α , γ )16O and a precision of about 10% is required to provide adequate constraints on stellar evolution. A measurement at the astrophysical energy, E 0 ≈ 300 keV , is unfeasible due to the extremely low cross section. Furthermore, the extrapolation of existing high-energy data is complicated by a complex reaction scheme. Besides direct measurements of 12C( α , γ )16O, the β-delayed α-decay of 16N and 12C + 4He elastic scattering provide additional information for the relevant 16O levels. In this Letter we present a new R-matrix analysis, where systematic uncertainties of the included data sets, in particular the absolute normalization, were treated in the fitting procedure. The data were selected according to rigorous criteria in order to reduce uncontrolled systematic effects and, finally, a Monte Carlo approach was used to evaluate the uncertainty at astrophysical energy. The resulting S factor, S ( 300 ) = 161 ± 19 stat − 2 sys + 8 keV b , is, for the first time, close to the required precision.

The radiative capture reaction C 12 ( α , γ ) O 16 has been investigated in the energy range E = 3.3 to 4.5 MeV. This experiment focused in particular on the cascade transition to the 0+ state at E x = 6.05 MeV in 16O and was performed by detecting the capture γ-rays with a NaI detector array at the windowless 4He gas target of the recoil mass separator ERNA in coincidence with the 16O ejectiles. The 6.05 MeV transition has been considered recently as a component accounting for up to 15% of the C 12 ( α , γ ) O 16 total cross section at astrophysical energies. The arrangement of the detector array yielded additional information on the γ-ray multipolarity, i.e. the ratio σ E 2 / σ E 1 , and it was found that the 6.05 MeV transition is entirely E2 in the studied energy range. The results for this transition are analyzed in an R-matrix formalism and extrapolated to the relevant Gamow energy of stellar helium burning, E 0 ≃ 300 keV . In contrast to a previous analysis, the present extrapolation suggests a negligible contribution from this amplitude, S 6.05 ( 300 ) 1 keV b . Additional data for cascade transitions to excited states at E x = 6.13 , 6.92, and 7.12 MeV, respectively, as well as to the ground state were obtained and the corresponding S factors in the studied energy range are given.

Toxoplasmic encephalitis (TE) continues to be a severe health problem despite the introduction of highly active antiretroviral therapy (HAART). To identify predictors for development of TE we compared demographic, clinical and diagnostic variables in AIDS patients with TE before (n = 102) or after the introduction (n = 70) of HAART at the Charité University Medicine in Berlin, Germany. Interestingly, patient characteristics did not differ significantly in the pre- and post-HAART groups. Sixty-eight percent of patients had CD4-cell counts of50/μl. Outcome after treatment with pyrimethamin plus sulfonamides or clindamycin (47% each) did not differ; adverse reactions were more frequent in patients receiving sulfonamides than in those receiving clindamycin (25% vs. 10.5%; p = 0.02). Interestingly, patients in the post HAART group had not received (82.9%) or had not taken HAART adequately (17.1%). Concurrent diagnosis of TE and HIV was significantly more often in the post- compared to the pre-HAART group (49 vs. 26%, respectively; p 0.001). Thus, despite the introduction of HAART, awareness of opportunistic infections in HIV patients is warranted. High rates of unawareness of HIV infection should make public health efforts focus on early identification of HIV infection and initiation of and compliance with HAART.

For improved measurements of the key astrophysical reaction C-12(alpha, gamma)O-16 in inverted kinematics, a recoil separator ERNA is being developed at the 4 MV Dynamitron tandem accelerator in Bochum to detect directly the O-16 recoils with about 50% efficiency. Calculations of the ion beam optics including all filtering and focusing elements of ERNA are presented. Since the C-12 projectiles and the O-16 recoils have essentially the same momentum, and since the C-12 ion beam emerging from the accelerator passes through a momentum filter (analysing magnet), the C-12 ion beam must be as free as possible from O-16 contamination for ERNA to succeed. In the present work, the O-16 contamination was reduced from a level of 1 x 10(-11) to a level below 2 x 10(-29) by the installation of Wien filters both before and after the analysing magnet. The measurement of these and other beam specifications involved other parts of the final ERNA layout - sequentially a Wien filter, a 60 degrees dipole magnet, another Wien filter, and a Delta E-E telescope. The setup led to a measured suppression factor of 5 x 10(-18) for the C-12 ion beam. The experiments also indicate that an almost free choice of the charge state for the O-16 recoils is possible in the separator.

(7)Be decays via electron capture and therefore its half-life is expected to depend on the electron density at the nucleus. We measured the (7)Be half-life in palladium, tungsten, zirconium and tantalum metals, in order to investigate the influence of the quasi-free electrons in metals on the probability of electron capture. The (7)Be samples were obtained implanting a 4.85 MeV pure radioactive (7)Be ion beam. The (7)Be half-life was determined measuring the 478 keV gamma decay following the electron capture by means of HPGe detectors. In order to reduce systematic errors, we planned to perform independent measurements in three different laboratories: Naples (Italy), Bochum (Germany) and Debrecen (Hungary). On the basis of the first results, we do not find a (7)Be half-life change within the experimental errors of 0.4%. RI Fulop, Zsolt/B-2262-2008

The electron screening in the 7Li ( p , α ) α reaction has been studied at E p = 30 to 100 keV for different environments: Li2WO4 insulator, Li metal, and PdLi alloys. For the insulator a screening potential energy of U e = 185 ± 150 eV was observed, consistent with previous work and the atomic adiabatic limit. However, for the Li metal and the PdLi alloys we find large values of U e = 1280 ± 60 and 3790 ± 330 eV , respectively: the values can be explained by the plasma model of Debye applied to the quasi-free metallic electrons in these samples. Similar results have been found for the 6Li ( p , α ) 3 He reaction supporting the hypothesis of the isotopic independence of the electron screening effect. The data together with previous studies of d ( d , p ) t and 9Be ( p , α ) 6 Li in metals verify the Debye model scaling U e ∝ Z t (charge number of target).

The astrophysically relevant 3 He ( d , p ) 4 He reaction was indirectly studied by means of the Trojan Horse Method applied to the 6 Li ( 3 He , pα ) 4 He three body process performed at 5 and 6 MeV. The bare astrophysical S(E)-factor extracted in Modified Plane Wave Born Approximation was compared with the free behaviour and an independent estimate of the screening potential was obtained, confirming the discrepancy with the adiabatic limit.

PURPOSE To compare virtual with flexible bronchoscopy for the detection of bronchial stenoses. MATERIALS AND METHODS In a retrospective study, we compared the results of 26 patients, who had clinical suspected pathologies of the tracheobronchial airways and underwent both flexible bronchoscopy and multislice CT with 3D surface rendering of the airways. Flexible bronchoscopy and virtual bronchoscopy were compared as to the rate of detecting bronchial stenoses. For statistical analysis, we divided the tracheobronchial tree in the following sections: trachea, 2 main bronchi, 6 lobar bronchi, 18 segmental bronchi and 36 subsegmental bronchi, corresponding to 63 bronchial sections for each patient (on average) and a total of 1638 bronchial sections for all 26 patients. We graded the bronchial stenosis as less than 50 %, as 50 to 95 % and as complete obstruction. RESULTS Virtual bronchoscopy detected 25 bronchial stenoses, while flexible bronchoscopy only revealed 17 stenoses. Stenoses with a diameter less than 50 % were found with virtual bronchoscopy 14 times and with flexible bronchoscopy 10 times. Stenoses with a diameter between 50 and 95 % were detected 7 and 4 times, respectively, and complete obstructions 4 and 3 times, respectively. Tracheobronchial stenoses were well recognized with virtual bronchoscopy. Moreover, the virtual method enabled the visualization of high-grade stenoses and post-stenotic areas that could not be passed by the fiberoptic bronchoscope. Virtual bronchoscopy detected stenoses at a higher rate but the difference was not statistically significant (stenoses < 50 %: p = 0.352, 50 - 95 %: p = 0.339, complete obstruction: p = 0.696). CONCLUSION Virtual bronchoscopy is a useful non-invasive method for the diagnostic evaluation of the tracheobronchial tree. In comparison with flexible bronchoscopy, virtual bronchoscopy is superior in revealing high-grade stenoses and visualizing post-stenotic areas.

The reaction $^{17}$O$(p,\gamma)^{18}$F influences hydrogen-burning nucleosynthesis in several stellar sites, such as red giants, asymptotic giant branch (AGB) stars, massive stars and classical novae. In the relevant temperature range for these environments ($T_{9}=0.01-0.4), the main contributions to the rate of this reaction are the direct capture process, two low lying narrow resonances ($E_{r}=65.1$ and 183 keV) and the low-energy tails of two broad resonances ($E_{r}=557$ and 677 keV). Previous measurements and calculations give contradictory results for the direct capture contribution which in turn increases the uncertainty of the reaction rate. In addition, very few published cross section data exist for the high energy region that might affect the interpretation of the direct capture and the contributions of the broad resonances in the lower energy range. This work aims to address these issues. The reaction cross section was measured in a wide proton energy range ($E_{c.m.}=345$ - 1700 keV) and at several angles ($\theta_{lab}=0^{\circ},45^{\circ},90^{\circ},135^{\circ}$). The observed primary $\gamma$-transitions were used as input in an $R$-matrix code in order to obtain the contribution of the direct capture and the two broad resonances to the low-energy region. The extrapolated S-factor from the present data is in good agreement with the existing literature data in the low-energy region. A new reaction rate was calculated from the combined results of this work and literature S-factor determinations. Resonance strengths and branchings are reported for several $^{18}$F states. We were able to extrapolate the astrophysical S-factor of the reaction $^{17}$O$(p,\gamma)^{18}$F at low energies from cross section data taken at higher energies. No significant changes in the nucleosynthesis are expected from the newly calculated reaction rate., Comment: Accepted in Physical Review C

The radiative capture reaction View the MathML source has been investigated in the energy range E=3.3 to 4.5 MeV. This experiment focused in particular on the cascade transition to the 0+ state at Ex=6.05 MeV in 16O and was performed by detecting the capture γ-rays with a NaI detector array at the windowless 4He gas target of the recoil mass separator ERNA in coincidence with the 16O ejectiles. The 6.05 MeV transition has been considered recently as a component accounting for up to 15% of the View the MathML source total cross section at astrophysical energies. The arrangement of the detector array yielded additional information on the γ-ray multipolarity, i.e. the ratio σE2/σE1, and it was found that the 6.05 MeV transition is entirely E2 in the studied energy range. The results for this transition are analyzed in an R-matrix formalism and extrapolated to the relevant Gamow energy of stellar helium burning, E0≃300 keV. In contrast to a previous analysis, the present extrapolation suggests a negligible contribution from this amplitude, View the MathML source. Additional data for cascade transitions to excited states at Ex=6.13, 6.92, and 7.12 MeV, respectively, as well as to the ground state were obtained and the corresponding S factors in the studied energy range are given.

The recoil separator ERNA (European Recoil Separator for Nuclear Astrophysics) for improved measurements of the astrophysical key reaction C-12(alpha, gamma)O-16 is being developed at the 4 MV Dynamitron tandem accelerator in Bochum to detect directly the O-16 recoils. The total detection efficiency of about 50 % allows direct measurements in a much wider energy range than previously accessible. In addition this technique allows improved measurements not hampered by cosmic background problems when compared to gamma -ray detection.

The efficacy, safety, and tolerability of voriconazole and fluconazole were compared in 391 immunocompromised patients with mycology- and biopsy-proven esophageal candidiasis. Primary efficacy analysis (256 patients) of esophageal treatment as assessed by esophagoscopy revealed success rates of 98.3% with voriconazole and 95.1% with fluconazole. The 95% confidence interval for the difference in success rates ranged from -1.0% to 7.5%. The overall safety and tolerability of both antifungals were acceptable. Fewer patients discontinued voriconazole treatment because of insufficient clinical response (4 patients [2.0%] vs. 5 patients [2.6%]). More patients discontinued voriconazole than fluconazole treatment because of laboratory test abnormalities (7 patients [3.5%] vs. 2 patients [1.0%]) or treatment-related adverse events (5 patients [2.5%] vs. 1 patient [0.5%]). The most frequent adverse events (23%) with voriconazole were mild, transient visual disturbances. Voriconazole (200 mg, b.i.d.) was shown to be at least as effective as fluconazole in the treatment of biopsy-proven esophageal candidiasis in immunocompromised patients.

The reaction He 3 ( α , γ ) Be 7 plays a key role for the understanding of the production of 7Li in Big Bang nucleosynthesis as well as for the high energy component of the solar neutrino spectrum. The uncertainty in its absolute cross-section arises from systematic differences of the available data sets. In various experiments the cross-section was measured by the detection of the prompt γ -rays or by the off-line observation of the γ -rays following the 7Be electron capture; in a few cases both observations were carried out. We report on a new approach based on the use of the recoil separator ERNA (European Recoil separator for Nuclear Astrophysics) to detect directly the 7Be recoils as well as the prompt γ -rays in coincidence with the recoils. We present technical details of the experimental setup, such as a recirculating 3He gas target, a TOF-E end detector, and a NaI detector array. In addition, the measurement of the separator acceptance is discussed and compared to the expected recoil emittance. The feasibility of the approach is demonstrated by sample spectra, indicating cross-section determinations of He 3 ( α , γ ) Be 7 in the energy range E cm = 0.7 – 3.3 MeV with high precision and accuracy.

Understanding the electron screening effect in the laboratory is critical for a correct interpretation of low‐energy nuclear reactions in stars. Extensive studies of the electron screening effect in deuterated metals (54 metals) and other environments have been carried out in Bochum in the last 4 years. Experimental results of anomalous enhancements have been interpreted in terms of the Debye plasma model applied to quasi‐free metallic electrons. For the d(d,p)t reaction in metallic environments, the variation of hydrogen solubility in the samples as a function of temperature has also been measured, showing an anti‐correlation with screening enhancement as expected. Within this model, the deduced number of valence electrons per metallic atom also agrees with the corresponding number from the Hall coefficient. Recently, the expected temperature dependence of the screening potential has been verified together with the expected Zt scaling (with the metallic host) of the Debye radius. Preliminary results on the 7Li(p,α) and 6Li(p,α) reactions in Li2WO4 insulator, Li metal and PdLi alloys confirm the expected behaviour of the screening effect and further supports the applicability of the Debye model. Indeed, the proposed model also accounts for the high screening potential (Ue = 900±50 eV) observed in previous studies of the reactions 9Be(p,α) and 9Be(p,d), which was not understood at the time. A review of all these results will be presented.

The 3He(α, γ)7Be reaction plays an important role in the interpretation of the results of the solar neutrino experiments, since the estimate of the oscillation parameters relies on the solar neutrino spectrum, calculated by solar models. The high energy component in this spectrum is mainly produced by the decay of 7Be and 8B. The uncertainty in the 3He(α, γ) 7Be cross section is also one of the largest contributions to the uncertainty on the predicted primordial 7Li abundance in Big Bang Nucleosynthesis calculations. Previous measurements of the 3He(α, γ)7Be cross section have been performed detecting the capture γ-rays or, alternatively, measuring the activity of the synthesized 7Be. While the results of the two different approaches agree on the energy dependence of the astrophysical S factor, they disagree in the extrapolated S34(0) value at a 3σ level. A novel approach uses the European Recoil separator for Nuclear Astrophysics (ERNA) to detect directly the 7Be ions produced in the reaction and, additionally, the coincident detection of the capture γ-rays. © 2006 American Institute of Physics.

The electron capture half life of 7 Be implanted into different metals has been measured with high precision in order to search for a possible dependence of the decay rate on the electron configuration around the 7 Be atoms. In order to reduce systematic errors, the half life in different metals is measured by three laboratories simultaneously using different experimental setups. The measurements and data analysis are in progress, preliminary results are presented.

The total cross section of 12C(alpha,gamma)16O was measured for the first time by a direct and ungated detection of the 16O recoils. This measurement in inverse kinematics using the recoil mass separator ERNA in combination with a windowless He gas target allowed to collect data with high precision in the energy range E=1.9 to 4.9 MeV. The data represent new information for the determination of the astrophysical S(E) factor.

The electron screening in the Li-7(p, alpha)alpha reaction has been studied at E-p = 30 to 100 keV for different environments: Li2WO4 insulator, Li metal, and PdLi alloys. For the insulator a screening potential energy of U-e = 185 +/- 150 eV was observed, consistent with previous work and the atomic adiabatic limit. However, for the Li metal and the PdLi alloys we find large values of U-e = 1280 +/- 60 and 3790 +/- 330 eV, respectively: the values can be explained by the plasma model of Debye applied to the quasi-free metallic electrons in these samples. Similar results have been found for the Li-6(p, alpha)He-3 reaction supporting the hypothesis of the isotopic independence of the electron screening effect. The data together with previous studies of d(d, p)t and Be-9(p, alpha)Li-6 in metals verify the Debye model scaling U-e proportional to Z(t) (charge number of target)

For improved cross-section measurements of the reaction 12C(α,γ)16O in inverted kinematics, a recoil separator ERNA is developed at the 4MV Dynamitron tandem accelerator in Bochum to detect directly the 16O recoils with high efficiency. The 16O recoils are produced by the 12C projectiles in a windowless 4He gas target. We report on the pressure profile of the gas target, the beam suppression by the separator, and the first observation of the 16O recoils at selected energies. © 2003 Elsevier B.V. All rights reserved.

For the electron capture of Be-7 in the metallic environments Pd and In the Be-7 half-life was observed to increase by 0.9 +/- 0.2 and 0.7 +/- 0.2%, respectively, while in the insulator Li2O it was unchanged within experimental error (all samples cooled to T = 12K). The observations are consistent with the predictions of the Debye plasma model applied to the quasi-free electrons in the metals.

C( 12 C;a) 20 Ne and 12 C( 12 C; p) 23 Na are the most important reactions during the carbon burning phase in stars. Direct measurements at the relevant astrophysical energy (E=1.5 0.3MeV) are very challenging because of the extremely small cross sections involved and of the high beam-induced background originating from impurities in the targets. In addition, persistent resonant structures at low energies are not well understood and make the extrapolation of the cross section from high energy data very uncertain. As a preliminary step towards the measurements of the 12 C( 12 C;a) 20 Ne and 12 C( 12 C; p) 23 Na reactions we intend to investigate the behaviour of targets under beam bombardment, specifically the quantitative measurement of hydrogen and deuterium content of highly pure stable carbon targets in relation to target temperature. Experiments are taking place at the CIRCE accelerator in Caserta, Italy and preliminary results are presented here.

A second high current accelerator of 400 kV has been installed at the underground laboratory of Gran Sasso, called LUNA II. We describe this new facility as well as measurements of the proton beam characteristics: absolute energy, energy spread, and long-term energy stability. The absolute energy was determined to a precision of +/-300 eV at E-p = 130-400 keV using the energy of the capture gamma-ray transition of C-12(p,gamma)N-13 as well as resonance energies at E-p = 309-389 keV of Na-23(p, gamma)Mg-24, Mg-26(p, gamma)Al-27, and Mg-25(p, gamma)Al-26. The resonance studies led to a proton energy spread of better than 100 eV and a long-term energy stability of 5 eV per hour.

A new measurement of the cross section of 7Be(p, $ \gamma$ )8B will be done in inverted kinematics with the recoil separator ERNA at the CIRCE laboratory in Caserta, Italy. The 8B recoils will be produced in a windowless hydrogen gas target. We report here on the construction and characterization of the gas cell. In detail we describe measurements for target density, the profile determination via the 7Li(p, p’)7Li* reaction as well as the role and performance of a gaseous post-stripper.

Exhaust emissions from a motorway have been monitored for a year in a joint project by the State of Lower Saxony and Volkswagen. Measurements were performed by the Fraunhofer Institut fur Toxikologie und Aerosolforschung in Hannover. As dispersion models alone are unable to reproduce the behaviour of nitrogen oxides and ozone, a simplified air parcel model has been developed. This model includes, in addition to pure dispersion, some basic reactions of nitrogen oxides and ozone, but neglects reactions with hydrocarbons. A comparison with the observed concentrations shows that the model gives acceptable results if some restrictions with respect to meteorological conditions are taken into account.

Despite the great amount of literature concerning toxoplasmic encephalitis in AIDS patients, little is known about extracerebral toxoplasmosis. Therefore we conducted a study of 80 autopsy cases to estimate the frequency of extracerebral toxoplasmosis. A control group of 50 cases was completely negative for all markers applied. In 35 of the 80 AIDS-cases (43.7%), organisms could be detected. In 13 cases (16.2%) there was an extracerebral toxoplasmosis; 4 cases (5%) showed only extracerebral involvement and in 9 cases (11.2%), extracerebral toxoplasmosis occurred in combination with cerebral manifestations. In 22 cases (27.5%), only cerebral toxoplasmosis was found. The following organs were involved: cardiac muscle (15%), lungs (6.2%), liver (5%), pancreas (5%), gastrointestinal tract (6.2%), adrenal glands (5%), lymph nodes (5%) and testis (3.7%). In individual cases further organs, not mentioned above, were involved. Pseudocysts could be demonstrated within necroses and inflammatory foci by conventional staining, whereas trophozoites became apparent only immunohistologically.

The 3He(alpha,gamma)7Be reaction presently represents the largest nuclear uncertainty in the predicted solar neutrino flux and has important implications on the big bang nucleosynthesis, i.e., the production of primordial 7Li. We present here the results of an experiment using the recoil separator ERNA (European Recoil separator for Nuclear Astrophysics) to detect directly the 7Be ejectiles. In addition, off-beam activation and coincidence gamma-ray measurements were performed at selected energies. At energies above 1 MeV a large discrepancy compared to previous results is observed both in the absolute value and in the energy dependence of the cross section. Based on the available data and models, a robust estimate of the cross section at the astrophysical relevant energies is proposed.

The 3He(alpha,gamma)7Be reaction presently represents the largest nuclear uncertainty in the predicted solar neutrino flux and has important implications on the big bang nucleosynthesis, i.e., the production of primordial 7Li. We present here the results of an experiment using the recoil separator ERNA (European Recoil separator for Nuclear Astrophysics) to detect directly the 7Be ejectiles. In addition, off-beam activation and coincidence gamma-ray measurements were performed at selected energies. At energies above 1 MeV a large discrepancy compared to previous results is observed both in the absolute value and in the energy dependence of the cross section. Based on the available data and models, a robust estimate of the cross section at the astrophysical relevant energies is proposed.

We report on a new lifetime measurement of the ${E}_{x}=6792$ keV state in $^{15}\mathrm{O}$ via the Doppler-shift attenuation method at the $E=259$ keV resonance in the reaction $^{14}\mathrm{N}$($p,\ensuremath{\gamma}$)$^{15}\mathrm{O}$. This subthreshold state is of particular importance for the determination of the ground state astrophysical $S$ factor of $^{14}\mathrm{N}$($p,\ensuremath{\gamma}$)$^{15}\mathrm{O}$ at stellar energies. The measurement technique has been significantly improved over that used in previous work. The conclusion of a finite lifetime drawn there cannot be confirmed with the present data. In addition, the lifetimes of the two states at ${E}_{x}=5181$ and 6172 keV have been measured with the same technique in order to verify the experimental method. We observe an attenuation factor $F(\ensuremath{\tau})g0.98$ for the ${E}_{x}=6172$ and 6792 keV states, respectively, corresponding to $\ensuremath{\tau}l0.77$ fs. The attenuation factor for the ${E}_{x}=5181$ keV state results in $F(\ensuremath{\tau})=0.78\ifmmode\pm\else\textpm\fi{}0.02$ corresponding to $\ensuremath{\tau}=8.4\ifmmode\pm\else\textpm\fi{}1.0$ fs, which is in excellent agreement with literature.

The set of fusion reactions {sup 12}C+{sup 12}C play a critical role in several astrophysical processes. In a recent experiment, the fusion reactions {sup 12}C+{sup 12}C have been studied at E{sub CM} = 2.10 to 4.75 MeV by {gamma}-ray spectroscopy using a C target of ultra-low hydrogen contamination. The deduced astrophysical S-tilde(E) factor exhibits previously unknown resonances at E{

Volkswagen has developed an on-board exhaust emissions measurement system which enables the direct and continuous determination of the mass emissions of the exhaust components HC, CO, NO x , and CO 2 , together with the real-time fuel consumption. The system can be installed in each type of passenger car and can be operated under all traffic and weather conditions. The system has proved itself in numerous on-the-road test runs. The test programs cover measurements in urban areas, on country roads, and on motor ways. The results of each test run are printed out immediately after completion of the test. As an example, some results of a high-speed motor way test program are presented.

The traffic on motorways is a source for CO, NOx and hydrocarbons. In a joined project by the state of Lower Saxony and Volkswagen the atmospheric transport of pollutants from a motorway was observed for one year. NO, NO2, CO and O3 were continuously monitored at different distances up to 600 m from the motorway, together with meteorological data. The measurements were performed by the “Fraunhofer-Institut fur Toxikologie und Aerosolforschung in Hannover”. Two models are used by Volkswagen to describe the atmospheric transport: A Gaussian dispersion model including deposition and a Lagrange-type model including selected photochemical reactions. Both models can be used to calculate the dispersion of CO and NOx taking into account the deposition of NO2. The Lagrange-type model additionally allows to calculate the concentrations of NO, NO2 and O3 under the influence of solar radiation. The applicability of the models is confined to windspeeds ≥1 m/s. Wind directions parallel to the motorway are also excluded. As the measurements show considerable fluctuations, it is necessary to perform statistical evaluations, comprising a greater number of observations. The verification is still in progress.

In the metal Cu cooled to T = 12K the alpha-decay half-life of Po-210 nuclides, located inside the metal, was measured to be shorter by 6.3 +/- 1.4% compared to that at room temperature. RI Aliotta, Marialuisa /H-2567-2012

For the β--decay of 198Au in a Au metallic environment the half-life was observed to be longer by 0.4±0.7% at room temperature (T = 293K) and by 4.0±0.7% when the metal was cooled to T = 12K, both compared to the literature value of T 1/2 = 2.6943±0.0008d.

The fusion reactions 12C(12C,alpha)20Ne and 12C(12C,p)23Na have been studied from E=2.10 to 4.75 MeV by gamma-ray spectroscopy using a C target with ultralow hydrogen contamination. The deduced astrophysical S(E)* factor exhibits new resonances at Eor =3.0 MeV, in particular, a strong resonance at E=2.14 MeV, which lies at the high-energy tail of the Gamow peak. The resonance increases the present nonresonant reaction rate of the alpha channel by a factor of 5 near T=8x10(8) K. Because of the resonance structure, extrapolation to the Gamow energy EG=1.5 MeV is quite uncertain. An experimental approach based on an underground accelerator placed in a salt mine in combination with a high efficiency detection setup could provide data over the full EG energy range.

The $^{3}\mathrm{He}$($d,p$)$^{4}\mathrm{He}$ reaction has been studied from ${E}_{c.m.}=600$ keV down to astrophysical energies by means of the ``Trojan horse'' method using the $^{6}\mathrm{Li}$($^{3}\mathrm{He}$,$p\ensuremath{\alpha}$)$^{4}\mathrm{He}$ three-body reaction at ${E}_{\mathrm{lab}}=5$ and 6 MeV. Coincidence spectra were measured in kinematic conditions favoring the quasifree $^{3}\mathrm{He}+^{2}\mathrm{H}$ process. The bare astrophysical factor ${S}_{b}(E)$ for the $^{3}\mathrm{He}$($d,p$)$^{4}\mathrm{He}$ reaction was extracted from the three-body cross section in the modified plane-wave Born approximation. Comparison with the ${S}_{b}$ extrapolation from the free two-body data is presented. The independent estimate of the screening potential as obtained with the present work seems to confirm the theoretical adiabatic limit.

To compare virtual with flexible bronchoscopy for the detection of bronchial stenoses.In a retrospective study, we compared the results of 26 patients, who had clinical suspected pathologies of the tracheobronchial airways and underwent both flexible bronchoscopy and multislice CT with 3D surface rendering of the airways. Flexible bronchoscopy and virtual bronchoscopy were compared as to the rate of detecting bronchial stenoses. For statistical analysis, we divided the tracheobronchial tree in the following sections: trachea, 2 main bronchi, 6 lobar bronchi, 18 segmental bronchi and 36 subsegmental bronchi, corresponding to 63 bronchial sections for each patient (on average) and a total of 1638 bronchial sections for all 26 patients. We graded the bronchial stenosis as less than 50 %, as 50 to 95 % and as complete obstruction.Virtual bronchoscopy detected 25 bronchial stenoses, while flexible bronchoscopy only revealed 17 stenoses. Stenoses with a diameter less than 50 % were found with virtual bronchoscopy 14 times and with flexible bronchoscopy 10 times. Stenoses with a diameter between 50 and 95 % were detected 7 and 4 times, respectively, and complete obstructions 4 and 3 times, respectively. Tracheobronchial stenoses were well recognized with virtual bronchoscopy. Moreover, the virtual method enabled the visualization of high-grade stenoses and post-stenotic areas that could not be passed by the fiberoptic bronchoscope. Virtual bronchoscopy detected stenoses at a higher rate but the difference was not statistically significant (stenoses50 %: p = 0.352, 50 - 95 %: p = 0.339, complete obstruction: p = 0.696).Virtual bronchoscopy is a useful non-invasive method for the diagnostic evaluation of the tracheobronchial tree. In comparison with flexible bronchoscopy, virtual bronchoscopy is superior in revealing high-grade stenoses and visualizing post-stenotic areas.

For improved cross section measurements of the reaction 12 C ( α , γ ) 16 O in inverted kinematics, a recoil separator ERNA is developed at the 4 MV Dynamitron tandem accelerator in Bochum to detect directly the 16O recoils with high efficiency. The 16O recoils are produced by the 12C projectiles in a windowless 4He gas target. We report on the charge state distribution of the 16O recoils, the gas target density, the beam heating of the gas target, and the acceptance of the separator along the extended gas target.