Human immunodeficiency virus type 1 reverse transcription is stimulated by Tat from other lentiviruses

The tat gene is required by HIV-1 for efficient reverse transcription and this function of Tat can be distinguished from its role in transcription by RNA polymerase II using tat point mutations that abrogate each function independently The mechanism of Tat's role in reverse transcription, however, is not known, nor is it known whether this role is conserved among trans-activating factors in other retroviruses. Here we examine the abilities of heterologous viral trans-activating proteins from jembrana disease virus (jTat), HIV-2 (Tat2), and equine infectious anemia virus (eTat) to substitute for HIV-1 Tat (Tat1) and restore reverse transcription in HIV-1 carrying an inactivated tat gene. Natural endogenous reverse transcription assays showed that trans-activators from some retroviruses (Tat2 and jTat, but not eTat) could substitute for Tat1 in complementation of HIV-1 reverse transcription. Finally, we show that Y47 is critical for Tat1 to function in reverse transcription, but not HIV-1 gene expression. We mutated the homologous position in jTat to H62Y and found it did not improve its ability to stimulate reverse transcription, but an H62A mutation did inhibit jTat complementation. These data highlight the finding that the role of Tat in reverse transcription is not related to trans-activation and demonstrate that other tat genes conserve this function. (C) 2002 Elsevier Science (USA).

Reliability factors in business software: volatility, requirements and end-users

Many business-oriented software applications are subject to frequent changes in requirements. This paper shows that, ceteris paribus, increases in the volatility of system requirements decrease the reliability of software. Further, systems that exhibit high volatility during the development phase are likely to have lower reliability during their operational phase. In addition to the typically higher volatility of requirements, end-users who specify the requirements of business-oriented systems are usually less technically oriented than people who specify the requirements of compilers, radar tracking systems or medical equipment. Hence, the characteristics of software reliability problems for business-oriented systems are likely to differ significantly from those of more technically oriented systems.

Gene-Environment Interaction Effects on Behavioral Variation and Risk of Complex Disorders: The Example of Alcoholism and Other Psychiatric Disorders

There have been few replicated examples of genotype x environment interaction effects on behavioral variation or risk of psychiatric disorder. We review some of the factors that have made detection of genotype x environment interaction effects difficult, and show how genotype x shared environment interaction (GxSE) effects are commonly confounded with genetic parameters in data from twin pairs reared together. Historic data on twin pairs reared apart can in principle be used to estimate such GxSE effects, but have rarely been used for this purpose. We illustrate this using previously published data from the Swedish Adoption Twin Study of Aging (SATSA), which suggest that GxSE effects could account for as much as 25% of the total variance in risk of becoming a regular smoker. Since few separated twin pairs will be available for study in the future, we also consider methods for modifying variance components linkage analysis to allow for environmental interactions with linked loci.

A portable load cell for in-situ ore impact breakage testing

This paper discusses the design and characterisation of a short, and hence portable impact load cell for in-situ quantification of ore breakage properties under impact loading conditions. Much literature has been published in the past two decades about impact load cells for ore breakage testing. It has been conclusively shown that such machines yield significant quantitative energy-fragmentation information about industrial ores. However, documented load cells are all laboratory systems that are not adapted for in-situ testing due to their dimensions and operating requirements. The authors report on a new portable impact load cell designed specifically for in-situ testing. The load cell is 1.5 m in height and weighs 30 kg. Its physical and operating characteristics are detailed in the paper. This includes physical dimensions, calibration and signal deconvolution. Emphasis is placed on the deconvolution issue, which is significant for such a short load cell. Finally, it is conclusively shown that the short load cell is quantitatively as accurate as its larger laboratory analogues. (C) 2062 Elsevier Science B.V. All rights reserved.

Differential requirements for COPI coats in formation of replication complexes among three genera of Picornaviridae

Picornavirus RNA replication requires the formation of replication complexes (RCs). consisting of virus-induced vesicles associated with viral nonstructural proteins and RNA. Brefeldin A (BFA) has been shown to strongly inhibit RNA replication of poliovirus but not of encephalomyocarditis virus (EMCV). Here, we demonstrate that the replication of parechovirus 1 (ParV1) is partly resistant to BFA, whereas echovirus 11 (EV11) replication is strongly inhibited. Since BFA inhibits COPI-dependent steps in endoplasmic reticulum (ER)-Golgi transport, we tested a hypothesis that different picornaviruses may have differential requirements for COPI in the formation of their RCs. Using immunofluorescence and cryo-immunoelectron microscopy we examined the association of a COPI component, beta-COP, with the RCs of EMCV, ParV1, and EV11 EMCV RCs did not contain beta-COP. In contrast, beta-COP appeared to be specifically distributed to the RCs of EV11 In ParV1-infected cells beta-COP was largely dispersed throughout the cytoplasm, with some being present in the RCs. These results suggest that there are differences in the involvement of COPI in the formation of the RCs of various picornaviruses, corresponding to their differential sensitivity to BFA. EMCV RCs are likely to be formed immediately after vesicle budding from the ER, prior to COPI association with membranes. ParV1 RCs are formed from COPI-containing membranes but COPI is unlikely to be directly involved in their formation, whereas formation of EV11 RCs appears to be dependent on COPI association with membranes.

Cross-reactivity of Sydney funnel-web spider antivenom: neutralization of the in vitro toxicity of other Australian funnel-web (Atrax and Hadronyche) spider venoms

Australian funnel-web spiders are recognized as one of the most venomous spiders to humans world-wide. Funnel-web spider antivenom (FWS AV) reverses clinical effects of envenomation from the bite of Atrax robustus and a small number of related Hadronyche species. This study assessed the in vitro efficacy of FWS AV in neutralization of the effects of funnel-web spider venoms, collected from various locations along the eastern seaboard of Australia, in an isolated chick biventer cervicis nerve-muscle preparation. Venoms were separated by SDS-PAGE electrophoresis to compare protein composition and transblotted for Western blotting and incubation with FWS AV. SDS-PAGE of venoms revealed similar low and high molecular weight protein bands. Western blotting with FWS AV showed similar antivenom binding with protein bands in all the venoms tested. Male funnel-web spider venoms (7/7) and female venoms (5110) produced muscle contracture and fasciculation when applied to the nerve-muscle preparation. Venom effects were reversed by subsequent application of FWS AV or prevented by pretreatment of the preparation with antivenom. FWS AV appears to reverse the in vitro toxicity of a number of funnel-web spider venoms from the eastern seaboard of Australia. FWS AV should be effective in the treatment of envenomation from most, if not all, species of Australian funnel-web spiders. (C) 2001 Elsevier Science Ltd. All rights reserved.

Dual mode cooling house in the warm humid tropics

Passive techniques as an alternative to artificial cooling can bring important energy, environmental, financial, operational and qualitative benefits. However, regions such as the wet tropics can reach high levels of thermal stress in which passive means alone are unable to provide appropriate thermal comfort standards for some parts of the year. Despite a great accumulation of empirical information on the passive performance of houses for either free-running or conditioned modes, very little work has been done on the thermal performance of buildings that can operate with a mixed-running strategy in warm-humid climates. Buildings with such design features are able to balance the needs for comfort, privacy, and energy efficiency during different periods of the year. As free-running and conditioned modes are believed by many to be 'opposite' approaches, and have been presented as separate strategies, this paper demonstrates that not all parameters are directly opposite and a possible dual-mode integrated operation can be used for warm-humid locations for maximum comfort and minimum energy requirements. For this purpose, simulation runs using ESP-R (University of Strathclyde, ESRU, UK) were based on the climate data of Darwin (Australia) and on the ventilation styles of the house: free running and conditioned. Design features applicable to both, i.e. for a dual mode operation could be identified and the differences between conditioned and free running were demonstrated and proved not to be totally conflicting and therefore suitable for a dual mode operation. Different daily usage profiles (five use patterns were defined), and zoning of sleeping and living areas are presented. The dual mode use patterns compared to the base case house, for all the user possibilities, had improved performances of 17-52%, when compared to the free-running mode and 66-98% when compared to the conditioned mode. Simulation runs using other warm-humid climates (Miami, USA; Sao Luis, Brazil; Kuala Lumpur, Malaysia) were also conducted and compared to the results found for Darwin. (C) 2002 Elsevier Science Ltd. All rights reserved.

Communicating vegetation management science to land managers and other stakeholders

Science communication. including extension services. plays a key role in achieving sustainable native vegetation management. One of the pivotal aspects of the debate on sustainable vegetation management is the scientific information underpinning policy-making. In recent years. extension services have Shifted their focus from top-down technology transfer to bottom-up participation and empowerment. I here has also been a broadening of communication strategies to recognise the range of stakeholders involved in native vegetation management and to encompass environmental concerns. This paper examines the differences between government approaches to extension services to deliver policy and the need for effective communication to address broader science issues that underpin native vegetation management. The importance of knowing the learning styles of the stakeholders involved in native vegetation management is discussed at a time of increasing reliance on mass communication for information exchange and the importance of personal communication to achieve on-ground sustainable management. Critical factors for effective science-management communication are identified Such as: (i) undertaking scientific studies (research) with community involvement, acceptance and agreed understanding of project objectives (ii) realistic community consultation periods: (iii) matching communication channels with stakeholder needs; (iv) combining scientific with local knowledge in in holistic (biophysical and social) approach to understanding in issued and (v) regional partnerships. These communication factors are considered to be essential to implementing on-ground natural resource management strategics and actions, including those concerned with native vegetation management.

The JK three-product cyclone - performance and potential applications

In spite of their wide application in comminution circuits, hydrocyclones have at least one significant disadvantage in that their operation inherently tends to return the fine denser liberated minerals to the grinding mill. This results in unnecessary overgrinding which adds to the milling cost and can adversely affect the efficiency of downstream processes. In an attempt to solve this problem, a three-product cyclone has been developed at the Julius Kruttschnitt Mineral Research Centre (JKMRC) to generate a second overflow in which the fine dense liberated minerals can be selectively concentrated for further treatment. In this paper, the design and operation of the three-product cyclone are described. The influence of the length of the second vortex finder on the performance of a 150-mm unit treating a mixture of magnetite and silica is investigated. Conventional cyclone tests were also conducted under similar conditions. Using the operational performance data of the three-product and conventional cyclones, it is shown that by optimising the length of the second vortex finder, the amount of fine dense mineral particles that reports to the three-product cyclone underflow can be reduced. In addition, the three-product cyclone can be used to generate middlings stream that may be more suitable for flash flotation than the conventional cyclone underflow, or alternatively, could be classified with a microscreen to separate the valuables from the gangue. At the same time, a fines stream having similar properties to those of the conventional overflow can be obtained. Hence, if the middlings stream was used as feed for flash flotation or microscreening, the fines stream could be used in lieu of the conventional overflow without compromising the feed requirements for the conventional flotation circuit. Some of the other potential applications of the new cyclone are described. (C) 2003 Elsevier Science B.V. All rights reserved.

Phylogenetic relationships of Hepatozoon (Haemogregarina) boigae Hepatozoon sp. Haemogregarina clelandi and Haemoproteus chelodina from Australian reptiles to other Apicomplexa based on cladistic analyses of ultrastructural and life-cycle characters

The phylogeny of representative haemozoan species of the phylum Apicomplexa was reconstructed by cladistic analyses of ultrastructural and life-cycle characteristics. The analysis incorporated 4 apicomplexans previously not included in phylogenetic reconstructions: Haemogregarina clelandi from the Brisbane River tortoise (Emydura signata), Hepatozoon sp. from the slaty grey snake (Stegonotus cucullatus), Hepatozoon (Haemogregarina) boigae from the brown tree snake (Boiga irregularis), and Haemoproteus chelodina from the saw-shelled tortoise (Elseya latisternum). There was no apparent correlation between parasite phylogeny and that of their vertebrate hosts, but there appeared to be some relationship between parasites and their intermediate hosts, suggestive of parasite/vector co-evolution.

The validity of publication and citation counts for Sociology and other selected disciplines

The use of bibliometric data is a means of comparing. research productivity and scholarly. impact for individuals, work groups, institutions and nations within and between disciplines. Central to this debate is the notion that disciplines differ in the ways in which,they exchange ideas and disseminate information and therefore have diverse publishing and citation patterns. In this article we use two different approaches to compiling bibliometric data to compare publishing patterns of five different disciplines that encompass Molecular Biology; Administration/Political Science, Psychology,. Philosophy and Sociology/Anthropology. We find that the social sciences differ from each other as well as from the physical sciences in their publication and citation patterns. Further, while the different ways of organizing the data produce somewhat different results, the substantive findings for the general patterning of publications and citations of disciplines are consistent for both data sets. Sociology/Anthropology, when compared with the other disciplines, shows substantial differences across universities.