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We present state-selective measurements on the NH2+ + H+ and NH+ + H+ + H dissociation channels following single-photon double ionization at 61.5 eV of neutral NH3, where the two photoelectrons and two cations are measured in coincidence using 3D momentum imaging. Three dication electronic states are identified to contribute to the NH2+ + H+ dissociation channel, where the excitation in one of the three states undergoes intersystem crossing prior to dissociation, producing a cold NH2+ fragment. In contrast, the other two states directly dissociate, producing a ro-vibrationally excited NH2+ fragment with roughly 1 eV of internal energy. The NH+ + H+ + H channel is fed by direct dissociation from three intermediate dication states, one of which is shared with the NH2+ + H+ channel. We find evidence of autoionization contributing to each of the double ionization channels. The distributions of the relative emission angle between the two photoelectrons, as well as the relative angle between the recoil axis of the molecular breakup and the polarization vector of the ionizing field, are also presented to provide insight on both the photoionization and photodissociation mechanisms for the different dication states.

We report measurements on the H++H+ fragmentation channel following direct single-photon double ionization of neutral NH3 at 61.5 eV, where the two photoelectrons and two protons are measured in coincidence using three-dimensional (3D) momentum imaging. We identify four dication electronic states that contribute to H++H+ dissociation, based on our multireference configuration-interaction calculations of the dication potential energy surfaces. The extracted branching ratios between these four dication electronic states are presented. Of the four dication electronic states, three dissociate in a concerted process, while the fourth undergoes a sequential fragmentation mechanism. We find evidence that the neutral NH fragment or intermediate NH+ ion is markedly rovibrationally excited. We also identify differences in the relative emission angle between the two photoelectrons as a function of their energy sharing for the four different dication states, which bare some similarities to previous observations made on atomic targets.

We present an experimental investigation of symmetry breaking of H2 and D2 molecules after single photoionization due to the Coulomb field of the emitted slow electron interacting with the parent cation during dissociation. The experiments were carried out by measuring the three-dimensional momentum vectors of the photoelectron and recoiling ion in coincidence using a reaction microscope. For photon energies close to threshold, the low-energy photoelectron influences the dissociation process, which results in an asymmetric molecular frame photoelectron angular distribution. This can be explained by the retroaction of the Coulomb field of the photoelectron on its parent ion and has been recently experimentally demonstrated by M. Waitz et al. [Phys. Rev. Lett. 116, 043001 (2016)PRLTAO0031-900710.1103/PhysRevLett.116.043001], confirming theoretical predictions by V. V. Serov and A. S. Kheifets [Phys. Rev. A 89, 031402(R) (2014)PLRAAN1050-294710.1103/PhysRevA.89.031402]. High-momentum resolution and a new series of photon energies just above the dissociation threshold enable the observation of a strong influence of the electron energy and nuclear kinetic energy on the electron localization process for energies below ∼100 meV, which so far has neither been observed nor discussed by theory. Exploring the limitations of the retroaction mechanism at our lowest photon energy, we are able to single out a sensitive testbed and present data of non-Born-Oppenheimer dynamics of the simplest molecular system for future benchmark computational treatments.

We present a combined experimental and theoretical investigation of the electron dynamics and body-frame angular dependence of valence photo-single ionization of CF4 and subsequent dissociation into CF3+ and F. Ionization from a valence t2 orbital shows overlapping shape resonances close to threshold that couple to the same total symmetry, leading to striking changes in the photoelectron angular distributions when viewed in the body-frame.

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To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1468-5957.2010.02222.x Byline: Oyvind Bohren (1), R. Oystein Strom (1) Keywords: corporate governance; board composition; regulation Abstract: Abstract: This paper analyzes the economic rationale for board regulation in place and for introducing new regulation in the future. We relate the value of the firm to the use of employee directors, board independence, directors with multiple seats, and to gender diversity. Our evidence shows that the firm creates more value for its owners when the board has no employee directors, when its directors have strong links to other boards, and when gender diversity is low. We find no relationship between firm performance and board independence. These characteristics of value-creating boards support neither popular opinion nor the current politics of corporate governance. Author Affiliation: (1)The authors are respectively from the Norwegian School of Management (B1) and Oslo University College, Norway. This paper has benefited from comments by an anonymous referee, Paul Andre (associate editor), Marc Goergen, Paul Guest, Kartnik Krishnan, Bang Dang Nguyen, Oyvind Norli, Richard Priestley, Trond Randoy, David C. Smith, participants at the 2007 meetings of the European Finance Association in Ljubljana, the 6th European Workshop on Corporate Governance and Investment (Universitat de les Illes Balears), and the Workshop on the Politics of Corporate Governance (Copenhagen Business School). The authors acknowledge financial support from the Research Council of Norway (grant no. 154949/510) and data from Verdipapirsentralen ASA, the Oslo Stock Exchange, and the Centre for Corporate Governance Research. Article History: (Paper received May 2009, revised version accepted May 2010) Article note: (*) Address for correspondence:Oyvind Bohren, Norwegian School of Management (BI), Nydalsveien 37, N-0442 Oslo, Norway., e-mail: oyvind.bohren@bi.no

We carried out a brief campaign in September 1998 to determine Jupiter's radio spectrum at frequencies spanning a range from 74 MHz up to 8 GHz. Eleven different telescopes were used in this effort, each uniquely suited to observe at a particular frequency. We find that Jupiter's spectrum is basically flat shortwards of 1-2 GHz, and drops off steeply at frequencies greater than 2 GHz. We compared the 1998 spectrum with a spectrum (330 MHz-8 GHz) obtained in June 1994, and report a large difference in spectral shape, being most pronounced at the lowest frequencies. The difference seems to be linear with log(v), with the largest deviations at the lowest frequencies (v). We have compared our spectra with calculations of Jupiter's synchrotron radiation using several published models. The spectral shape is determined by the energy-dependent spatial distribution of the electrons in Jupiter's magnetic field, which in turn is determined by the detailed diffusion process across L-shells and in pitch angle, as well as energy-dependent particle losses. The spectral shape observed in September 1998 can be matched well if the electron energy spectrum at L = 6 is modeled by a double power law [E.sup.-a] (1 + [(E/[E.sub.0])).sup.-b], with a = 0.4, b = 3, [E.sub.0] = 100 MeV, and a lifetime against local losses [[tau].sub.0] = 6 x [10.sup.7] s. In June 1994 the observations can be matched equally well with two different sets of parameters: (1) a = 0.6, b = 3, [E.sub.0] = 100 MeV, [[tau].sub.0] = 6 x [10.sup.7] s, or (2) a = 0.4, b = 3, [E.sub.0] = 100 MeV, [[tau].sub.0] = 8.6 x [10.sup.6] s. We attribute the large variation in spectral shape between 1994 and 1998 to pitch angle scattering, coulomb scattering and/or energy degradation by dust in Jupiter's inner radiation belts. Keywords: Jupiter; Magnetosphere; Radio observations

We present a combined experimental and theoretical investigation of the electron dynamics and body-frame angular dependence of valence photo-single ionization of CF4 and subsequent dissociation into CF3+ and F. Ionization from a valence t2 orbital shows overlapping shape resonances close to threshold that couple to the same total symmetry, leading to striking changes in the photoelectron angular distributions when viewed in the body-frame. [ABSTRACT FROM AUTHOR]

Gamma-ray burst (GRB) 111215A was bright at X-ray and radio frequencies, but not detected in the optical or near-infrared (nIR) down to deep limits. We have observed the GRB afterglow with the Westerbork Synthesis Radio Telescope and Arcminute Microkelvin Imager at radio frequencies, with the William Herschel Telescope and Nordic Optical Telescope in the nIR/optical, and with the Chandra X-ray Observatory. We have combined our data with the Swift X-Ray Telescope monitoring, and radio and millimetre observations from the literature to perform broad-band modelling, and determined the macro- and microphysical parameters of the GRB blast wave. By combining the broad-band modelling results with our nIR upper limits we have put constraints on the extinction in the host galaxy. This is consistent with the optical extinction we have derived from the excess X-ray absorption, and higher than in other dark bursts for which similar modelling work has been performed. We also present deep imaging of the host galaxy with the Keck I telescope, Spitzer Space Telescope, and Hubble Space Telescope (HST), which resulted in a well-constrained photometric redshift, giving credence to the tentative spectroscopic redshift we obtained with the Keck II telescope, and estimates for the stellar mass and star formation rate of the host. Finally, our high-resolution HST images of the host galaxy show that the GRB afterglow position is offset from the brightest regions of the host galaxy, in contrast to studies of optically bright GRBs. [ABSTRACT FROM AUTHOR]

GRB 130427A was extremely bright as a result of occurring at low redshift whilst the energetics were more typical of high-redshift gamma-ray bursts (GRBs). We collected well-sampled light curves at 1.4 and 4.8 GHz of GRB 130427A with the Westerbork Synthesis Radio Telescope (WSRT); and we obtained its most accurate position with the European Very Long Baseline Interferometry Network (EVN). Our flux density measurements are combined with all the data available at radio, optical and X-ray frequencies to perform broad-band modelling in the framework of a reverse–forward shock model and a two-component jet model, and we discuss the implications and limitations of both models. The low density inferred from the modelling implies that the GRB 130427A progenitor is either a very low metallicity Wolf–Rayet star, or a rapidly rotating, low-metallicity O star. We also find that the fraction of the energy in electrons is evolving over time, and that the fraction of electrons participating in a relativistic power-law energy distribution is less than 15 per cent. We observed intraday variability during the earliest WSRT observations, and the source sizes inferred from our modelling are consistent with this variability being due to interstellar scintillation effects. Finally, we present and discuss our limits on the linear and circular polarization, which are among the deepest limits of GRB radio polarization to date. [ABSTRACT FROM AUTHOR]

The giant radio galaxy 4C 73.08 has been observed with the Westerbork Telescope at a wavelength of 21 cm. The radio map obtained is a significant improvement upon previous maps in terms of the combination of high dynamic range, sensitivity and angular resolution. The new map shows that the jet, previously thought to be one-sided, is probably symmetrical with one arm almost lost in the background of extended lobe emission. The brighter, more compact lobe also displays more intense emission from its hotspot and jet. The jets line up well with the nucleus and hotspots, although the hotspot on one side deviates from the lobe major axis. The unusual feature of the radio source's morphology is the existence of curved ridges running transverse to the source major axis. Three of the other galaxies in the 4C 73.08 group are also weak radio sources. We further detect radio emission from the foreground galaxies NGC 2957 and 2963, which form a small group. A background galaxy has double radio components of moderate size which we have mapped; there is an optical companion at the same redshift. Another extended source may be associated with a Two Micron All Sky Survey galaxy. [ABSTRACT FROM AUTHOR]

ABSTRACT The optical field of the giant radio galaxy (GRG) 4C 73.08 has been spectroscopically investigated to look for companions to the host 7Zw 292. We have taken spectra of 12 candidates and have determined redshifts for all of them. When combined with the previously known redshift of 7Zw 292, we find that the radio source is accompanied by a small group of nine galaxies, of which the GRG host is the brightest. Seven members of the group lie within 350 kpc of 7Zw 292, gathered around the brighter, more compact component of the double radio source. The whole group has a velocity dispersion of ∼270 km s−1. We discuss this result in the light of the X-ray emission which has been detected from the region. 4C 73.08 follows the pattern found in other GRGs of being associated with a small group, but not falling in a rich cluster. [ABSTRACT FROM AUTHOR]

ABSTRACT We have investigated the environment of the giant radio galaxy NGC 315 with its associated group of galaxies selected by their spectroscopic redshifts. Observations were made with the 2.16-m optical telescope at Xinglong Station of the National Astronomical Observatories of China. In addition to 25 galaxies near NGC 315 with published redshifts, we have successfully determined 21 new redshifts of candidates, five of which are previously unknown members of the NGC 315 galaxy group. We examine and discuss the spatial structure and kinematics of this group (which is part of the Perseus-Pisces filament). Nearly 40 per cent of its members are concentrated near NGC 315, close to the emission from its brighter radio jet. The X-ray luminosity implied by the optical velocity dispersion is higher than that derived empirically from observations of other groups, suggesting that X-ray-emitting gas within the NGC 315 group has a low density. This may be one reason for the size of the radio source. [ABSTRACT FROM AUTHOR]

We have investigated galaxies around NGC 6251 to search for an associated group. Our main goal is to study the environment around the giant radio galaxy to better understand the reasons for its size and structure. To this end, we have made spectroscopic observations with the 2.16-m optical telescope at Xinglong Station of the National Astronomical Observatories of China (NAOC) and obtained spectra of 45 objects (including four likely stars). The redshifts give us 10 new galaxies in a group, which are in addition to seven previously known members. The 17 galaxies' positions are compared with the radio emission. The optical velocity dispersion of group members within 0.7 Mpc of NGC 6251 is not consistent with that expected from correlation curves of X-ray luminosity versus velocity dispersion . We briefly discuss this result, suggesting that in the NGC 6251 group, the density of X-ray emitting gas is unusually low, and this is the main reason for the size of the radio source. [ABSTRACT FROM AUTHOR]

We show that at wavelengths comparable to the length of the shower produced by an Ultra-High Energy cosmic ray or neutrino, radio signals are an extremely efficient way to detect these particles. First results are presented of an analysis of 20 hours of observation data for NuMoon project using the Westerbork Synthesis Radio Telescope to search for short radio pulses from the Moon. [ABSTRACT FROM AUTHOR]

Background/Aim: The aim of this prospective controlled study was to compare the effects of two therapies for menopause on factor VII (FVII) and hemostatic variables. Methods: Postmenopausal women were assigned to receive one of the following treatments: transdermal estradiol (TTS E2; 50 μg) combined in a continuous sequential regimen with oral medroxyprogesterone acetate (MPA; 10 mg/day for 12 days) (group A; n = 20), tibolone (2.5 mg/day) (group B; n = 21) or placebo (group C; n = 19). Sixty women completed the 1-year treatment and underwent follow-up examinations after 3, 6 and 12 months. Results: TTS E2/MPA induced various changes in procoagulatory factors. At 12 months, fibrinogen, activated FVII (FVIIa) and coagulative FVII (FVIIc) had increased by 10.7, 12.9 and 3.7%, respectively. Among the fibrinolytic factors, plasminogen and α2-antiplasmin increased by 11.3 and 7.2%, respectively. Lipoprotein(a) [Lp(a)] and antithrombin III (ATIII) did not show any significant variation. Tibolone induced some changes toward a more homogeneous antithrombotic profile. Fibrinogen, FVIIa and FVIIc decreased significantly by 7.5, 8.1 and 21.3%, respectively. Plasminogen increased (by 11.8%) and Lp(a) decreased (by 28.4%). ATIII was unchanged with tibolone therapy. Conclusion: Our results show that tibolone induces a significant reduction in FVIIc and Lp(a) and a greater enhancement of factors promoting fibrinolysis than the TTS E2/MPA regimen. Copyright © 2009 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

In the presence of somatostatin-14 or some of its receptorial agonists, the uptake of large neutral amino acids by isolated brain microvessels was found to be inhibited up to 50%, no other transport system being affected. Although the luminal and abluminal sides of brain endothelial cells are both capable of taking up large neutral amino acids, only uptake from the abluminal side appears to be inhibited by somatostatin. The involvement of a type-2 somatostatin receptor was suggested by assays with a series of receptor-specific somatostatin agonists, and was confirmed by the release of inhibition caused by a specific type-2 receptor antagonist. A type-2-specific mRNA was indeed shown to be present in both bovine brain microvessels ex vivo and primary cultures of endothelial cells from rat brain microvessels. [ABSTRACT FROM AUTHOR]