Behind the Essenes

A collection of essays by Philip Davies on aspects of the Dead Sea Scrolls. While composed to stand along, together these essays create a strong synthetic argument about the Essenes and the production of the Dead Sea Scrolls that remains important and challenging to the present day

Observations of the Structure and Dynamics of the Inner M87 Jet

M87 is the best source in which to study a jet at high resolution in gravitational units because it has a very high mass black hole and is nearby. The angular size of the black hole is second only to Sgr A*, which does not have a strong jet. The jet structure is edge brightened with a wide opening angle base and a weak counterjet. We have roughly annual observations for 17 years plus intensive monitoring at three week intervals for a year and five day intervals for 2.5 months made with the Very Long Baseline Array (VLBA) at 43 GHz. The inner jet shows very complex dynamics, with apparent motions both along and across the jet. Speeds from zero to over 2c are seen, with acceleration observed over the first 3 milli-arcseconds. The counterjet decreases in brightness much more rapidly than the main jet, as is expected from relativistic beaming in an accelerating jet oriented near the line-of-sight. Details of the structure and dynamics are discussed. The roughly annual observations show side-to-side motion of the whole jet with a characteristic time scale of about 9 years.Comment: 11 pages, 7 figures. Published in a special issue of Galaxies which is the proceedings of "Blazars through Sharp Multi-Wavelength Eyes" edited by J. L. Gomez, A. P. Marscher, and S. G. Jorsta

The literary structure of 1QM

Previous research on the Qumran scrolls, and in particular, IQM, has only recently involved the use of the most stringent literary - and form - critical techniques. These are of great value to Qumran studies; the history of the sect and its ideas can be learnt only when the texts are properly understood. IQM has been recognised by most scholars as a composite work, and XV-XIX has long been regarded as a unit. To this must be added II-IX which also comprises a single document. Both these documents are themselves composite. II-IX is a war-rule written in the Hasmonean period, and drawing on sources which originated in the Maccabean and immediate post Maccabean period. XV-XIX is a dualistic war-rule, which has developed from an earlier non-dualistic rule, of which col. XIV, 2-16a represents a small fragment. Cols. X-XII consist of a collection of liturgical pieces which have been found to reflect a Maccabean context in many cases. Col. XIII represent a fragment of liturgy probably associated with a covenant ceremony. Cols. II-IX, X-XII, XIII, XIV, and XV-XIX were collected and probably copied together; XV, 4-6a seems to refer to two documents which were independent at the time of writing, but have subsequently been incorporated into IQM - these are identified as II-IX and X-XII. XIII and XIV existed as fragments when they were brought together with the rest of the material from cols. II-IX, X-XII and XV-XIX. XV-XIX probably attained its present form in the second half of the first century B.C. In the first half of the first century A.D. a compiler produced from the collected documents a war-rule which included an introduction (col. I) written by the compiler. The final result is the War Scroll, the manuscript of which was written soon after the composition (= IQM). Its purpose is to prepare for the imminent war against the Romans

Photo induced Force Microscopy: chemical spectroscopy beyond the diffraction limit

Over the last decade remarkable advances have been made in creating spectroscopic tools to interrogate surface properties using electromagnetic radiation in the near field, achieving lateral resolutions in the nanometre range. We review recent work involving one of the most promising of these spectroscopic tools, photo induced force microscopy (PiFM), which uses mechanical detection of dipole-dipole interactions enabling nanometre resolved mapping of surface properties ranging from vibrational modes of adsorbates to plasmon resonances. We discuss the origin of contrast in PiFM images, its applications as a local probe of chemical species and for mapping local electric fields in areas as diverse as zeolite films and biometric recognition. In comparison with related techniques such as photo thermal infrared spectroscopy (PTIR) and tip enhanced Raman spectroscopy (TERS) PiFM has many advantages but perhaps its most successful application is in combination with other surface characterisation methods which provide information averaged over much greater surface areas. We discuss the most recent developments of PiFM technology which are leading to higher resolution images and are widening the range of environments in which the technique can be applied, and we consider how the field is likely to progress in the future

A Search for Environmental Effects on Type Ia Supernovae

We use integrated colors and B and V absolute magnitudes of Type Ia supernova (SN) host galaxies in order to search for environmental effects on the SN optical properties. With the new sample of 44 SNe we confirm the conclusion by Hamuy et al. (1996a) that bright events occur preferentially in young stellar environments. We find also that the brightest SNe occur in the least luminous galaxies, a possible indication that metal-poorer neighbourhoods produce the more luminous events. The interpretation of these results is made difficult, however, due to the fact that galaxies with younger stellar populations are also lower in luminosity. In an attempt to remove this ambiguity we use models for the line strengths in the absorption spectrum of five early-type galaxies, in order to estimate metallicities and ages of the SN host galaxies. With the addition of abundance estimates from nebular analysis of the emission spectra of three spiral galaxies, we find possible further evidence that luminous SNe are produced in metal-poor neighborhoods. Further spectroscopic observations of the SN host galaxies will be necessary to test these results and assist in disentangling the age/metallicity effects on Type Ia SNe.Comment: 14 pages, 5 figures, to appear in the September 2000 issue of The Astronomical Journa

Structural behaviour of copper chloride catalysts during the chlorination of CO to phosgene

The interaction of CO with an attapulgite-supported Cu(II)Cl2 catalyst has been examined in a micro-reactor arrangement. CO exposure to the dried, as-received catalyst at elevated temperatures leads to the formation of CO2 as the only identifiable product. However, phosgene production can be induced by a catalyst pre-treatment where the supported Cu(II)Cl2 sample is exposed to a diluted stream of chlorine. Subsequent CO exposure at ~ 370°C then leads to phosgene production. In order to investigate the origins of this atypical set of reaction characteristics, a series of x-ray absorption experiments were performed that were supplemented by DFT calculations. XANES measurements establish that at the elevated temperatures connected with phosgene formation, the catalyst is comprised of Cu+ and a small amount of Cu2+. Moreover, the data show that unique to the chlorine pre-treated sample, CO exposure at elevated temperature results in a short-lived oxidation of the copper. On the basis of calculated CO adsorption energies, DFT calculations indicate that a mixed Cu+/Cu2+ catalyst is required to support CO chemisorption

Practical guide for x-ray photoelectron spectroscopy: applications to the study of catalysts

X-ray photoelectron spectroscopy (XPS) has become a standard tool for the study of catalytic materials over the last two decades, and with the increasing popularity of turnkey XPS systems, the analysis of these types of materials is open to an even wider audience. However, increased accessibility leads to an increase in the number of new or inexperienced practitioners, leading to erroneous data collection and interpretation. Over many years of working on a wide range of catalytic materials, the authors have developed procedures for the planning and execution of XPS analysis and subsequent data analysis, and this guide has been produced to help users of all levels of expertise to question their approach toward analysis and get the most out of the technique and avoiding some common pitfalls

Spatial and temporal variations in interspecific interaction : impact of a recreational landscape

Anthropogenic activities, such as outdoor recreation, have the potential to change complex interactions between wildlife and livestock, with further consequences for the management of both animals, the environment, and disease transmission. We present the interaction amongst wildlife, livestock, and outdoor recreationists as a three-way interaction. Little is known about how recreational activities alter the interaction between herbivores in areas extensively used for recreational purposes. We investigate how hiking activity affects spatio-temporal co-occurrence between domestic sheep (Ovis aries) and red deer (Cervus elaphus). We used camera traps to capture the spatio-temporal distribution of red deer and sheep and used the distance from the hiking path as a proxy of hiking activity. We used generalized linear models to investigate the spatial distribution of sheep and deer. We analysed the activity patterns of sheep and deer and then calculated their coefficients of temporal overlap for each camera trap location. We compared these coefficients in relation to the distance from the hiking path. Finally, we used a generalized linear mixed-model to investigate which factors influence the spatio-temporal succession between deer and sheep. We do not find that sheep and red deer spatially avoid each other. The coefficient of temporal overlap varied with distance from the hiking trail, with stronger temporal co-occurrence at greater distances from the hiking trail. Red deer were more likely to be detected further from the path during the day, which increased the temporal overlap with sheep in these areas. This suggests that hiking pressure influences spatio-temporal interactions between sheep and deer, leading to greater temporal overlap in areas further from the hiking path due to red deer spatial avoidance of hikers. This impact of recreationists on the wildlife and livestock interaction can have consequences for the animals’ welfare, the vegetation they graze, their management, and disease transmission.Publisher PDFPeer reviewe