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This article represents a systematic effort to answer the question, What are archaeology’s most important scientific challenges? Starting with a crowd-sourced query directed broadly to the professional community of archaeologists, the authors augmented, prioritized, and refined the responses during a two-day workshop focused specifically on this question. The resulting 25 “grand challenges” focus on dynamic cultural processes and the operation of coupled human and natural systems. We organize these challenges into five topics: (1) emergence, communities, and complexity; (2) resilience, persistence, transformation, and collapse; (3) movement, mobility, and migration; (4) cognition, behavior, and identity; and (5) human-environment interactions. A discussion and a brief list of references accompany each question. An important goal in identifying these challenges is to inform decisions on infrastructure investments for archaeology. Our premise is that the highest priority investments should enable us to address the most important questions. Addressing many of these challenges will require both sophisticated modeling and large-scale synthetic research that are only now becoming possible. Although new archaeological fieldwork will be essential, the greatest pay off will derive from investments that provide sophisticated research access to the explosion in systematically collected archaeological data that has occurred over the last several decades.
The Magellanic System represents one of the best places to study the formation and evolution of galaxies. Photometric surveys of various depths, areas and wavelengths have had a significant impact on our understanding of the system; however, a complete picture is still lacking. VMC (the VISTA near-infrared YJKs survey of the Magellanic System) will provide new data to derive the spatially resolved star formation history and to construct a three-dimensional map of the system. These data combined with those from other ongoing and planned surveys will give us an absolutely unique view of the system opening up the doors to truly new science!
We present an investigation of the halo dynamics of M31 using planetary nebulae velocities. We have performed on-band [OIII] and off-band continuum imaging for a 3.6 square degree area centred on M31 and follow-up spectroscopy for over 600 planetary nebulae candidates. In the future the halo mass will be measured and the mass distribution and velocity anisotropy will be constrained as a function of radius.
Three fundamentally different methods were used to fabricate nanometric surface features on polymers or fused silica. Phase separation of binary polymer mixes resulted in randomly distributed features whose depth and shape could be tightly controlled over large areas. Colloidal resist patterned large areas randomly and uniformly with very fine spikes. In contrast e-beam and reactive ion etching were used to create a set of regular spaced pillars on an orthogonal pattern. Some of the surfaces were replicated by in situ polymerization, solvent casting, embossing or melt molding onto polystyrene (PS) or ε–poly caprolactone (ε–PCL). Nanometric features down to 60nm were imprinted onto the polymers with high fidelity. Cells were seeded onto the nanometric surfaces and adhesion, morphology and cytoskeleton investigated. Cells respond to regular features of 170/80nm (width/depth) with reduced adhesion and changes in overall morphology and cytoskeleton. Small nanofeatures (13nm, 35nm depth) made by phase separation on the other hand increased adhesion and promoted cytoskeletal differentiation. The responses of the cells are indicative that nanometric surface features are useful modifications on scaffolds for tissue engineering or on medical implants.
Deep Level Transient Spectroscopy (DLTS) is used to investigate the effect of SiC14 Reactive Ion Etching (RIE) on GaAs. At high power (150-80 W) with high DC self bias (380-240 V), five deep levels trapping electrons are observed at energies of 0.30, 0.42, 0.64, 0.86 and ∼0.8 eV below the conduction band edge. Depth profiling reveals an approximate exponential decay of the concentration of the deep levels. At low power the induced concentration falls, the small concentration of remaining deep levels is close to control (no etching) samples. The induced deep levels can account for reduced conductances in n+GaAs wires defined by RIE under similar experimental conditions.
This paper seeks to define and explain financial reinsurance, a type of reinsurance growing rapidly in the general insurance market. It provides criteria for underwriters and actuaries to understand the degree of risk transfer involved and the limitations on that risk transfer. It seeks to set out criteria, applicable to both insurer and reinsurer, for estimating reserves where financial reinsurance covers are involved and for compliance with supervisory requirements. Several examples are given of typical financial reinsurance contracts currently in use.
Dry etching can introduce defects into the material being etched. Simple expressions for both sidewall and top surface defect distributions may be obtained by assuming that the defects are introduced according to a phenomenological source function. Calculations of conductance based on these expressions are found to describe very well measurements on dry-etched wires and epilayers. Mechanisms by which defects can penetrate into the sample are discussed. The role of sample heating and defect diffusion is examined. In-situ measurements of sample temperature during a dry-etch run indicate that simple diffusion is insufficient to account entirely for the observed damage. Instead, dry-etch damage may arise from other mechanisms such as by knock-on replacement collisions, or via a channeling effect. A more complex form of diffusion may also affect the final damage distribution.
The Cosmic Background Explorer, launched November 18, 1989, has nearly completed its first full mapping of the sky with all three of its instruments: a Far Infrared Absolute Spectrophotometer (FIRAS) covering 0.1 to 10 mm, a set of Differential Microwave Radiometers (DMR) operating at 3.3, 5.7, and 9.6 mm, and a Diffuse Infrared Background Experiment (DIRBE) spanning 1 to 300 µm in ten bands. A preliminary map of the sky derived from DIRBE data is presented. Initial cosmological implications include: a limit on the Comptonization y parameter of 10−3, on the chemical potential μ parameter of 10−2, a strong limit on the existence of a hot smooth intergalactic medium, and a confirmation that the dipole anisotropy has the spectrum expected from a Doppler shift of a blackbody. There are no significant anisotropies in the microwave sky detected, other than from our own galaxy and a cosθ dipole anisotropy whose amplitude and direction agree with previous data. At shorter wavelengths, the sky spectrum and anisotropies are dominated by emission from ‘local’ sources of emission within our Galaxy and Solar System. Preliminary comparison of IRAS and DIRBE sky brightnesses toward the ecliptic poles shows the IRAS values to be significantly higher than found by DIRBE at 100 μm. We suggest the presence of gain and zero-point errors in the IRAS total brightness data. The spacecraft, instrument designs, and data reduction methods are described.
A two-stage screening strategy was used to study psychiatric morbidity and social problems in a consecutive series of out-patients with insulin-dependent diabetes mellitus. The prevalence of psychiatric morbidity was 18%, and consisted of depression, anxiety, and attendant symptoms. Patients reporting major social problems had significantly higher levels of psychiatric symptoms. Psychiatric morbidity was not associated with the presence of complications of diabetes.
Two-stage screening for psychiatric disorder was carried out with a sample of 99 male and 95 female outpatients with insulin-dependent diabetes mellitus, using the General Health Questionnaire and the Clinical Interview Schedule. The estimated prevalence of psychiatric disorder in this sample was 18%: only 28% of the psychiatric morbidity so identified was detected by physicians. In contrast, physicians rated 10% of the sample as psychiatric ‘cases’ using a simple 6-point scale.
1.1 Following the thalidomide tragedy, a Royal Commission was set up in March 1973 to examine and report on the circumstances in which anyone suffering personal injury should be entitled to compensation and on the amount, the form and the source of such compensation. The Commission also considered the extent to which dependants should be compensated for losses which they incurred arising from the injury or death of a victim. The Commission, whose chairman was Lord Pearson, took written evidence from 766 organizations or persons and oral evidence from 113. The Report of the Commission, published in March 1978, was in three volumes comprising in all 1,084 pages. Volume 2 (259 pages) contained detailed statistical information which had been produced from various sources. It is known that in many cases information had to be assembled from inadequate data, and the Commission pointed out that many of the figures were a matter of judgment. They ascribed degrees of reliability to each table, but in some cases they were probably over-optimistic. Volume 3 (280 pages) reported on practice overseas.
Monensin increases propionic acid production in the rumen and improves the efficiency of feed conversion in fattening cattle. Trials carried out in the USA showed that 200 mg monensin/head per day was the optimum dose for increasing the rate of live-weight gain in beef cattle at pasture.
Twelve pasture trials, involving a total of 434 beef cattle, were carried out during 1976 and 1977 to assess the efficacy of monensin for grazing cattle under European conditions. Each trial compared a group given 200 mg monensin/head per day in 0·5 to 10 kg of carrier supplement with a negative control group, fed blank supplement. The average initial live-weight was 260 kg and the average trial duration was 119 days. Daily live-weight gains of the control and monensin-treated cattle averaged 0·786 and 0·893 kg/head per day respectively, an advantage of 107g/head per day or 13·7 % in favour of the monensin treatment (P<0·001). The growth-promoting effect of monensin showed no tendency to diminish with time.
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