68 research outputs found
Constructing Tychonoff G-spaces which are not G-Tychonoff
No full textAbstractJan de Vries' compactification problem is whether every Tychonoff G-space can be equivariantly embedded in a compact G-space. In such a case, we say that G is a V-group. De Vries showed that every locally compact group G is a V-group. The first example of a non-V-group was constructed in 1988 by the first author. Until now, this was the only known counterexample. In this paper, we give a systematic method of constructing noncompactifiable G-spaces. We show that the class of non-V-groups is large and contains all second countable (even ℵ0-bounded) nonlocally precompact groups. This establishes the existence of monothetic (even cyclic) non-V-groups, answering a question of the first author. As a related result, we obtain a characterization of locally compact groups in terms of “G-normality”
Degei's descendants : spirits, place and people in pre-cession Fiji /
No full textOnline resource; title from PDF title page (ANU, viewed September 4, 2014).Includes bibliographical references.Aubrey Parke: an enthusiastic amateur in Fiji? -- Acknowledgements -- Preface -- Maps -- Fijian society: the islands of Fiji (general) -- Overview of project -- The ideological sense of Vanua -- Understanding traditional Fijian society -- Factors affecting development and interaction -- The Yavusa: the ideal and the reality -- The diversity of Fijian polities -- Overview of chapters 8-10 Fijian polities in three areas in the Yasayasa Vakara -- Polities of Rakiraki Tikina -- Polities of West Vuda Tikina -- Polities of Nadi Tikina -- Polities of Nawaka Tikina -- Overview of chapters 12-13 polities of the Natu Yasawa: the Yasawa Group -- The Tikina of Naviti -- The Tikina of Yasawa -- Conclusion -- Appendix A -- Appendix B -- Bibliography.JSTO
Developing low-cost intelligent wireless sensor networks for aquatic environments
No full textAquatic environments are extremely difficult for developing, deploying, and maintaining wireless sensor networks. Networks deployed in aquatic settings face multiple challenges, such as marine fowling of equipment, limited power supply, communications difficulties, and
restricted accessibility for maintaining and updating sensor nodes. The SEMAT project is an initiative to create "smart", low-cost, heterogeneous wireless sensor networks, tailored to alleviating the aforementioned constraints. Networks can be instantly deployable with minimal setup overheads and can utilise equipment from multiple vendors. This paper presents our experiences with developing the initial technologies to establish SEMAT for field tests. We present the design methodology and challenges faced for creating a marine-based heterogeneous wireless sensor network platform. The result is a low cost solution, with sufficient accuracy for undertaking a study into the factors contributing to Lyngbya algae blooms in Deception Bay, Queensland. The platform builds a case for the merits of the final SEMAT system, as ultimately many of the software and basic hardware challenges for future aquatic deployments have been overcome. This is significant as it allows researchers to focus on the area under study, rather than the specifics of setting up and managing the network
Application of Air Percussion Drilling Improves Drilling Efficiency in Horizontal Sandstone Wells
No full textAbstract
EQT Production has implemented a new technique for drilling horizontal wells in the hard formations of the Appalachian Basin. Air percussion drilling has been adopted for use horizontally in the Berea sandstone, a hard and abrasive sandstone reservoir that had been traditionally drilled with roller cone bits. The evolution of the technology started with a packed-hole assembly that was trialed on three wells using stabilizer placement to provide directional control in the horizontal. The results were promising as penetration rates increased, but many trips were required to keep the wellbore in the desired target zone. To improve directional control, a percussion BHA with a bent housing positive displacement motor (PDM) was implemented. The introduction of the positive displacement motor with the air hammer produced the same penetration rates seen in the packed-hole assembly while providing the directional control needed. Since mid 2009, the PDM percussion assembly has become the standard practice for drilling Berea horizontal wells, replacing the roller cone BHA. Through June 2010, over 40 wells have been drilled using the assembly. The lateral portion for a majority of the wells is now drilled in one run, reducing total drilling time from 22 to 13 days, dry hole costs by over one half and total well costs by about one third.</jats:p
Men and boys selling sex in the Bradford district
No full textThis report provides a summary of key findings from a study commissioned by Yorkshire MESMAC exploring the experiences and needs of men and boys who are involved in selling sex in the Bradford district. This study consisted of three related projects outlined below.
Project A: Survey of Agencies in the Bradford Area
The first author conducted an interviewbased survey of 31 representatives from 21 local statutory and voluntary sector agencies exploring their perceptions of the issue of men and boys involved in selling sex, and considering ways in which local services could best respond to their needs. Responses indicated that:
● 78% of agency representatives believed that young men selling sex in the Bradford area was an issue that needed to be addressed.
● 52% of agency representatives had direct evidence of young men who were involved in selling sex in the Bradford area.
● 87% felt that action should be taken to address the issue of young men involved in selling sex in the Bradford area. Suggestions offered are outlined on page 9.
Project B: Local Awareness of Men Selling Sex
Thirty-seven men under the age of 40 completed a short questionnaire (Appendix 2) exploring their levels of awareness and possible involvement in selling/purchasing sexual services. Results indicated that:
● Adverts for men selling sex had been observed by gay/bisexual and heterosexual men in the Bradford district.
● One-third of gay/bisexual men and one young heterosexual man had been approached by a man and offered sex for money on more than one occasion.
● 10% of the gay/bisexual men surveyed reported having sold sex.
Executive Summary
● Reasons for offering sexual services or receiving payment for sex included being pressurized to perform in pornographic videos or pictures, or receiving shelter/accommodation for the night.
Project C: Men Selling Sex
Seven men who sell or have sold sex in the Bradford area were interviewed by the first author using a structured interview schedule (see Appendix 3). Responses suggested that:
● Sex with young men under the age of 16 is sought by men in the Bradford area.
● Men who sell sex on the streets have less control over the types of sex for which payment is offered than those who are house/flat/hotel-based.
● Men who sell sex on the streets face much more violence than those who sell sex from a house/flat/hotel.
● Selling sex on the streets often follows a chance encounter with an exploitative older man during teenage years.
● Selling sex from a house/flat tends to be a deliberate decision by older men.
Recommendations
● Provision of a local support service responding to the needs of men and boys who are involved in selling sex.
● Commission further research exploring the issues highlighted in the report
Benefits of building wireless sensor networks on commodity hardware and software stacks
No full textThe majority of wireless sensor networks are built on bespoke platforms, that is, custom designed and built hardware with a light weight software stack. There are a number of advantages to this approach. First, the ability to closely match and minimise the resource requirements (e.g., power consumption and communications protocols) to those that are suitable for the intended deployment. Second, as an entire hardware and software stack is often designed or at least optimised for each deployment, the latest advances can be quickly incorporated. However, this model generally requires the expertise of hardware and software engineers to design and build the system. In turn, this increases the cost and tends to shift the focus away from the initial science towards the development of the wireless sensor networks. This paper explores the utility and practicality of building wireless sensor networks based on commercially available embedded single board computing platforms using standard consumer operating systems. Our test bed was built using Gumstix computing platform, running a Linux Operating System (OS) with a java-based middleware coupled to low-cost scientific grade sensors. Test deployments have found this to be a highly versatile solution, able to leverage the flexibility of commodity hardware and software while maintaining reasonable utility
Real time data streaming in sensor networks: integrating SAL with the RBNB Data Turbine
No full textDeveloping a large sensor-based observation system faces two serious challenges: 1) incompatible sensor technologies from different manufacturers; and 2) complexity of the data streaming process. Sensor Abstraction Layer (SAL) is a middleware integration platform which enables a single interface to view and control heterogeneous sensors regardless of the technologies involved. Although SAL addresses the software compatibility issue of sensors from different manufacturers, it provides limited support for real-time visualisation of the sensed data. Real-time data streaming is extremely useful for scientific modelling and presenting study results for which the sensor network has been designed to investigate. This limitation of SAL can be improved through using existing purpose-built technologies such as the Ring Buffer Network Bus Data Turbine. The Data Turbine is an open-source data management system which provides services for data stream management, routing, monitoring and visualisation. This paper introduces SAL-T (Transmission) which integrates SAL with the Data Turbine. SAL-T is an extra software layer that facilitates the management of the sensed data from SAL into the Data Turbine. Performance tests have been conducted using SAL-T in a simulated data streaming environment indicative of a wireless sensor network. The tests showed that SAL-T dramatically reduced network traffic and improved transmission times
Comment on the Minnesota Transracial Adoption Study
No full textData from the Minnesota transracial adoption study reported in Weinberg. Scarr, and Waldman (1992) is reanalyzed and shown to be consistent with the hypothesis that the mean black/white difference in IQ is significantly genetic in origin. Weinberg, Scarr, and Waldman (1992) presents follow-up data on their study of black, mixed-race, and white children adopted by white families. In retrospect, they summarize their conclusions from their initial assessment of the performance of the adoptees as indicating that "putative genetic racial differences do not account for a major portion of the IQ performance difference between racial groups" (p. 118) and they seem inclined to interpret their follow-up as consistent with that conclusion. Weinberg, in a relatively recent article, although one published before the appearance of the follow-up, takes the study to have "disputed the hypothesis that IQ differences between blacks and white are due to genetic differences" (Weinberg, 1989, p. 101), although he does allow that h 2, the proportion of variance between individuals in IQ explained by genetic variation, is .5. (To be completely explicit, we may use H 2 to denote the proportion of the variance between races in IQ that is explained by between-race genetic variation.) There is an ambiguity in this remark cited from Weinberg: It is not clear whether he means to deny that all between-race variance is explained by genetic differences between the races, which is a position no one holds, or to deny that any of the between-race variance is explained by such genetic differences. If Weinberg is disputing the latter claim, he is implicitly making the very adventurous assertion that all mean race differences are due to differences in the environments in which members of different races find themselves. What to call these various positions is more significant than most definitional questions because of the emotions surrounding the issue of the size of H 2. It may be considered unfair to define environmentalism as the hypothesis that H 2 = 0 and The author wishes to thank Arthur Jensen and an anonymous referee for help, criticisms, and suggestions
Comments on the paper by Marcus Miller and Sayantan Ghosal 'Managing Financial Crisis in Emerging Markets: New Developments in Review'.
No full textNo abstract is available for this item.
Loss of ash trees in riparian forests from emerald ash borer infestations has implications for aquatic invertebrate leaf-litter consumers (CJFR-2018-0259)
No full textRapid loss of ash trees in riparian forests from the invasive insect, emerald ash borer (EAB), could pose risk of altering organic matter inputs to water bodies that underpin many aquatic ecosystem processes. We measured the composition of riparian forests and their leaf litter contributions to headwater streams and determined the relative palatability of ash leaves and three other common riparian trees to aquatic invertebrate leaf-litter consumers (the stonefly, Pteronarcys sp., and the cranefly, Tipula sp.) in laboratory microcosms and whole invertebrate communities in forest streams. Ash trees contributed on average 24% to riparian tree density and 20% to total litterfall. Among the four common stream-side trees accounting for 65% of total litterfall, ash was the first or second most preferred food source for consumers. Leaf packs without ash decomposed at slower rates than packs containing 25-100% ash leaves. Preferential feeding on ash leaves infers a high quality food source selected by consumers, and this concurred with comparatively high N content and low C/N ratio of ash leaves. Aquatic invertebrate communities on leaf packs in streams differed among leaf mixtures with or without ash, although community dissimilarity was low. The loss of ash in riparian forests represents an EAB-induced reduction in a high-quality resource subsidy to organic matter consumers in streams. We discuss how this has implications for risk predictions and management response strategies.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
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