System Design and Capabilities of a Current Technology, Low-Cost, Small Satellite

Ball Aerospace, with its successful background and strong interest in low-cost lightweight satellites, is studying the designs of current technology satellites for a variety of launchers (e.g., STS/GAS, Pershing, Scout, Poseidon, Conestoga, Titan 11, ILV, and Delta II). Ball Aerospace has completed the design of a current technology, multi-mission, low-cost Scout-compatible satellite. This paper summarizes the system design features and capabilities of this Ball Scout Satellite (BSS). The BSS is designed to accommodate a wide range of Earth and celestially oriented missions, both spinning and 3-axis stabilized. The BSS design provides a marked improvement in payload support capabilities (mass, power, data rate, pointing, interfaces, flexibility, reliability, etc.) than was previously available with earlier Scout satellites, and at a lower cost in current-year dollars

The alien flora of the Cape of Good Hope Nature Reserve

An annotated species list of the alien vascular plant flora of the Cape of Good Hope Nature Reserve is presented. The flora comprises five gymnosperm and 68 angiosperm species that are definitely alien to the reserve and four angiosperm species that are possibly alien. The life-form distribution of the alien flora is shown to be significantly different from that of the indigenous flora; trees, shrubs and annual herbs are more important in the alien flora, and dwarf shrubs and perennial herbs are much less important. Biotic factors are suggested as being important in determining the success of alien invasions, in particular grazing by ungulates. The invasion rate is currently about one new species per year. By ceasing to introduce tree species and by restricting human disturbance, the rate of invasion of new species could be reduced

The history and effects of alien plant control in the Cape of Good Hope Nature Reserve, 1941–1987

Concern about the invasion of this reserve by alien trees and shrubs, principally Acacia cyclops, A. saligna, A. longifolia, Eucalyptus lehmannii and Pinus pinaster, was first expressed in 1941, 2years after its proclamation. Control operations were started by 1943 and were almost totally ineffective for at least the first 35years; no systematic control strategy was implemented, follow-up control work was inadequate to prevent reestablishment of felled thickets and the supervision of control teams was deficient. Linkage of control operations to firewood production was a significant factor in this failure. In 1974 a 10-year control strategy was drawn up and in the late 1970’s began to be effectively implemented. Surveys of 40 plots in the centre of the reserve in 1966, 1976–80 and 1986 showed increasing densities of species other than the easily controlled P. pinaster up to 1976–80. Since then almost all individuals>1,8m in height have been eliminated and indications from smaller height classes are that seed banks are being depleted. Explanations are advanced for the successes and failures experienced during the 47years of control. Some of the side-effects of these invasions and their control are discussed. One conclusion is that this reserve requires a qualified ecologist on its staff

In vivo imaging of cellular proliferation in colorectal cancer using positron emission tomography

Background and aims: Positron emission tomography (PET) using 18F labelled 2-fluoro-2-deoxy-D-glucose (18FDG) is an established imaging tool, although the recent development of a biologically stable thymidine analogue [18F] 3'-deoxy-3-fluorothymidine (18FLT) has allowed PET to image cellular proliferation by utilising the salvage pathway of DNA synthesis. In this study, we have compared uptake of 18FLT and 18FDG with MIB-1 immunohistochemistry to evaluate the role of PET in quantifying in vivo cellular proliferation in colorectal cancer (CRC). Patients and methods: Patients with resectable, primary, or recurrent CRC were prospectively studied. Thirteen lesions from 10 patients (five males, five females), median age 68 years (range 54–87), were evaluated. Patients underwent 18FDG and 18FLT PET scanning. Tracer uptake within lesions was quantified using standardised uptake values (SUVs). Histopathological examination and MIB-1 immunohistochemistry were performed on all lesions, and proliferation quantified by calculating a labelling index (% of MIB-1 positively stained nuclei within 1500 tumour cells). Results: Histology confirmed adenocarcinoma in 12 of 13 lesions; the remaining lesion was reactive. All eight extrahepatic lesions were visualised using both 18FLT and 18FDG. Three of the five resected liver metastases were also avid for 18FLT and showed high proliferation, while the remaining two lesions which demonstrated no uptake of 18FLT had correspondingly very low proliferation. There was a statistically significant positive correlation (r =0.8, p<0.01) between SUVs of the tumours visualised with 18FLT and the corresponding MIB-1 labelling indices. No such correlation was demonstrated with 18FDG avid lesions (r =0.4). Conclusions: 18FLT PET correlates with cellular proliferation markers in both primary and metastatic CRC. This technique could provide a mechanism for in vivo grading of malignancy and early prediction of response to adjuvant chemotherapy

Effective scraping in a scraped surface heat exchanger: some fluid flow analysis

An outline of mathematical models that have been used to understand the behaviour of scraped surface heat exchangers is presented. In particular the problem of the wear of the blades is considered. A simple model, exploiting known behaviour of viscous flow in corners and in wedges, and accounting for the forces on the blade is derived and solutions generated. The results shows initial rapid wear but that the wear rate goes to zero

Search for the hero: an investigation into the sports heroes of British sports fans

This is an initial study into British sports fans’ heroes. A questionnaire was sent to 95 students (average age ¼ 19.75) to identify their sporting hero, the hero’s sport and nationality and the reasons for this choice. Football was the most common source of sports heroes, identified by 49% of participants with a sporting hero. The majority (60%, N ¼ 48) of heroes chosen by participants were British, with David Beckham the most popular choice. Differences were observed between the gender of participants, gender of hero chosen and the reasons for choosing the hero. The most common reason for selecting a hero was a personal trait rather than skill, while in the questionnaire a category of Local Affiliation was added to those suggested by previous work. It was concluded that to become a hero athletes should combine skill with devotion to family, charity work and a place in popular culture

The Queensland Health Rural Generalist Pathway: providing a medical workforce for the bush

Introduction: Queensland Health's Rural Generalist Pathway is a supported career pathway for junior doctors to train in rural and remote medicine. The pathway joins evidence with policy to achieve professional recognition, credentialing, and industrial recognition. Methods: This article describes the principles underpinning the notion of rural generalism, the background to the establishment of the Rural Generalist Pathway in Queensland, Australia, how the pathway has been developed to meet the needs of Queensland's rural and remote communities, the implementation of the pathway, and the implications for other jurisdictions. Results: In 2007, 30 trainees commenced on the pathway, with total enrolment now of 182 in 2012. Trainees commence at the start of internship, completing their prevocational training component in postgraduate years 1 to 2. After prevocational certification they undertake advanced specialised training in a range of specialties, and then complete vocational training in a rural location, usually in their 4th to 5th postgraduate years. Trainees complete their general practice training through a Regional Training Provider, and achieve vocational registration by completion of appropriate fellowship assessment requirements. The pathway is managed by a geographically dispersed team of educators, clinicians and managers. The Rural Generalist team provide training and career advice, advocate for trainees and assist with negotiating posts. They map progress of trainees through the Vocational Indicative Planning process and arrange other educational activities including Rural Generalist workshops. Applications are often oversubscribed, with the intake growing to 41 in 2012, located at 10 intern training hospitals. In total 90 trainees have completed advanced specialised training as at the end of 2012. Conclusion: The Rural Generalist Pathway includes a challenging prevocational start to the career, the opportunity to specialise in a procedural skill or skills of interest and obtain general practice vocational training in a rural setting and appears to be proving an attractive choice for medical graduates seeking a challenging and varied career. Early evidence suggests that by recognizing and rewarding the worth of rural and remote practice, this strategy is creating its own supply line. From its initial roll-out in Queensland, rural generalist training continues to generate increased interest and enthusiasm across all Australian states and territories wishing to join this new wave of generalist practice. This new generation of health professionals for a new generation of services has the potential to provide the rural medical workforce the bush needs

Phylogenetic relationships of African Caecilians (Amphibia: Gymnophiona): insights from mitochondrial rRNA gene sequences

Africa (excluding the Seychelles) has a diverse caecilian fauna, including the endemic family Scolecomorphidae and six endemic genera of the more cosmopolitan Caeciliidae. Previous molecular phylogenetic studies have not included any caecilians from the African mainland. Partial 12S and 16S mitochondrial gene sequences were obtained for two species of the endemic African Scolecomorphidae and five species and four genera of African Caeciliids, aligned against previously reported sequences for 16 caecilian species, and analysed using parsimony, maximum likelihood, Bayesian and distance methods. Results are in agreement with traditional taxonomy in providing support for the monophyly of the African Caeciliid genera Boulengerula and Schistometopum and for the Scolecomorphidae. They disagree in indicating that the Caeciliidae is paraphyletic with respect to the Scolecomorphidae. Although more data from morphology and/or molecules will be required to resolve details of the interrelationships of the African caecilian genera, the data provide strong support for at least two origins of caecilians in which the eye is reduced and covered with bone, and do not support the hypotheses that the caecilian assemblages of Africa, and of East and of West Africa are monophyletic

Disks, Tori, and Cocoons: Emission and Absorption Diagnostics of AGN Environments

One of the most important problems in the study of active galaxies is understanding the detailed geometry, physics, and evolution of the central engines and their environments. The leading models involve an accretion disk and torus structure around a central dense object, thought to be a supermassive black hole. Gas found in the environment of AGN is associated with different structures: molecular accretion disks, larger scale atomic tori, ionized and neutral "cocoons" in which the nuclear regions can be embedded. All of them can be studied at radio wavelengths by various means. Here, we summarize the work that has been done to date in the radio band to characterize these structures. Much has been learned about the central few parsecs of AGN in the last few decades with contemporary instruments but the picture remains incomplete. In order to be able to define a more accurate model of this region, significant advances in sensitivity, spectral and angular resolution, and bandpass stability are required. The necessary advances will only be provided by the Square Kilometer Array and we discuss the possibilities that these dramatic improvements will open for the study of the gas in the central region of AGN.Comment: To appear in "Science with the Square Kilometer Array," eds. C. Carilli and S. Rawlings, New Astronomy Reviews (Elsevier: Amsterdam); 17 pages, 7 figures (four of them in separate gif/tif files) The full paper with high resolution images can be downloaded from http://www.astron.nl/~morganti/Papers/AGNenvironment.ps.g

Landau and dynamical instabilities of Bose-Einstein condensates with superfluid flow in a Kronig-Penney potential

We study the elementary excitations of Bose-Einstein condensates in a one-dimensional periodic potential and discuss the stability of superfluid flow based on the Kronig-Penney model. We analytically solve the Bogoliubov equations and calculate the excitation spectrum. The Landau and dynamical instabilities occur in the first condensate band when the superfluid velocity exceeds certain critical values, which agrees with the result of condensates in a sinusoidal potential. It is found that the onset of the Landau instability coincides with the point where the perfect transmission of low-energy excitations is forbidden, while the dynamical instability occurs when the effective mass is negative. It is well known that the condensate band has a peculiar structure called swallowtail when the periodic potential is shallow compared to the mean field energy. We find that the upper side of the swallowtail is dynamically unstable although the excitations have the linear dispersion reflecting the positive effective mass.Comment: 6 pages, 2 figures, Proceedings of the International Symposium on Quantum Fluids and Solids (QFS2006