X-ray source uses interchangeable target anodes to vary X-ray wavelength

Compact laboratory X ray tube generates X rays of various wavelengths by using interchangeable target anodes. The wavelength of the X rays depends on the metal from which the anode is made

A ruggedized thin-window proportional-counter tube

Design and testing of ruggedized, thin window proportional counter tube for detecting X rays in light element

The carbon abundance in two h 2 regions of the small Megallanic Cloud

Observations of the ultraviolet spectra of two locations in the H II region NGC 346 and of the entire H II region IC 1644 in the Small Magellanic Cloud (SMC) were made using the International Ultraviolet Explorer (IUE) satellite. The abundance of carbon in the nebulae was derived using theoretical model analysis combined with ground-based spectrophotometry of other emission lines. The abundance of C relative to H in the SMC was found to be lower by -0.9 dex compared with the Sun and lower by -0.8 dex compared with the Orion Nebula. This C deficiency is similar to that of O, Ne, S, and Ar in the SMC, but not as great as found for N. The sites and history of C nucleosynthesis in galaxies is similar to that of O, Ne, S, and Ar, in contrast to that of N, which appears to be more complex, perhaps because of a mixture of secondary primary sources or a significant contribution from intermediate-mass long-lived stars

Quantum key distribution over 122 km of standard telecom fiber

We report the first demonstration of quantum key distribution over a standard telecom fiber exceeding 100 km in length. Through careful optimisation of the interferometer and single photon detector, we achieve a quantum bit error ratio of 8.9% for a 122km link, allowing a secure shared key to be formed after error correction and privacy amplification. Key formation rates of up to 1.9 kbit/sec are achieved depending upon fiber length. We discuss the factors limiting the maximum fiber length in quantum cryptography

What Becomes of the Damned: Annihilationism Consistent with Nonexistent Objects

Annihilationism provides a fruitful point of contact between philosophers and theologians for further reflection on nonexistence. In this paper I articulate a key commitment of annihilationism; namely, that some persons cease to exist. Such a commitment, I argue, amounts to the claim that some persons exist at time t and then do not exist at t+1, become ‘annihilated objects.’ Claims about annihilated objects induct the annihilationist into a wider realism/anti-realism debate about nonexistent objects. I survey some major viewpoints in this debate. I then draw out some implications for each view for the annihilationist’s commitment to annihilated objects. I show that annihilationism is consistent with some forms of realism and anti-realism and inconsistent with others

High chemical abundances in stripped Virgo spiral galaxies

Based on a comparison of the oxygen abundances in H 2 regions in field and Virgo cluster late type spiral galaxies, Shields, Skillman, & Kennicutt (1991) suggested that the highly stripped spiral galaxies in the Virgo cluster have systematically higher abundances than comparable field galaxies. In April 1991 and May 1992 we used the blue channel spectrograph on the MMT to obtain new observations of 30 H 2 regions in Virgo spiral galaxies. These spectra cover the wavelength range from (O II) lambda 3727 to (S II) lambda 6731. We now have observed at least 4 H II regions in 9 spiral galaxies in the Virgo cluster. Combining (O II) and (O III) line strengths, we calculate the H II region oxygen abundances based on the empirical calibration of Edmunds & Pagel (1984). These observations show: (1) The stripped, low luminosity Virgo spirals (N4689, N4571) truly have abundances characteristic of much more luminous field spirals; (2) Virgo spirals which show no evidence of stripping (N4651, N4713) have abundances comparable to field galaxies; and (3) Evidence for transition galaxies (e.g., N4254, N4321), with marginally stripped disks and marginal abundance enhancements. The new observations presented here confirm the validity of the oxygen over-abundances in the stripped Virgo spirals. Shields et al. (1991) discussed two different mechanisms for producing the higher abundances in the disks of stripped galaxies in Virgo. The first is the supression of infall of near-primordial material, the second is the suppression of radial inflow of metal-poor gas. Distinguishing between the two cases will require more observations of the Virgo cluster spirals and a better understanding of which parameters determine the variation of abundance with radius in field spirals (cf., Garnett & Shields 1987)

Conceptualising dementia crisis and preferences for resolution: A public perspective

Background: Crisis intervention services for people with dementia in the United Kingdom are poorly defined with no standardized model of working. This may be due to the lack of a clear conceptualization of dementia crisis, resulting in variation in national service delivery. Methods: This study employed a novel public engagement questionnaire data collection technique with 57 participants to gain an updated perspective on the concept of health-related crisis from the point of view of the public. Results: Analysis revealed crisis as a transformational moment that may arrive unexpectedly but could also be the culmination of a sequence of events. Crisis resolution requires external and expert help, and associated feelings of panic and despair can engender the task of resolution by oneself insurmountable. Conclusions: Participants had clear expectations of crisis intervention services, with initial practical and emotional support to reduce risks, and a person-centered approach with family involvement