Discovery of a New Retrograde Trans-Neptunian Object: Hint of a Common Orbital Plane for Low Semimajor Axis, High-inclination TNOs and Centaurs

Although the majority of Centaurs are thought to have originated in the scattered disk, with the high-inclination members coming from the Oort cloud, the origin of the high-inclination component of trans-Neptunian objects (TNOs) remains uncertain. We report the discovery of a retrograde TNO, which we nickname “Niku,” detected by the Pan-STARRS 1 Outer Solar System Survey. Our numerical integrations show that the orbital dynamics of Niku are very similar to that of 2008 KV42 (Drac), with a half-life of ˜500 Myr. Comparing similar high-inclination TNOs and Centaurs (q > 10 au, a <100 au, and i > 60°), we find that these objects exhibit a surprising clustering of ascending node, and occupy a common orbital plane. This orbital configuration has high statistical significance: 3.8-σ. An unknown mechanism is required to explain the observed clustering. This discovery may provide a pathway to investigating a possible reservoir of high-inclination objects.

Images of Africa and the resilience of ignorance

Images about Africa in the northern hemisphere are generally negative and pessimistic. In spite of instant global communication, why have these images persisted till date? This contribution shall revisit these perceptions and the images embodying them to unearth the motivations and rationale. The central argument, based on some narratives and experiences, is that ignorance feeds these images and stereotypes. Furthermore, positionality of non-African experts and some groups of African scholars and activists contribute to this culture of ignorance and paternalism. The contribution shall end with an ethical evaluation of the persistence of the images and the extent of moral responsibility of the authors and carriers of the racist stereotypes embedded in the images. (DIPF/Orig.)

Automated Discovery of Social Networks in Online Learning Communities

As a way to gain greater insights into the operation of online communities, this dissertation applies automated text mining techniques to text-based communication to identify, describe and evaluate underlying social networks among online community members. The main thrust of the study is to automate the discovery of social ties that form between community members, using only the digital footprints left behind in their online forum postings. Currently, one of the most common but time consuming methods for discovering social ties between people is to ask questions about their perceived social ties. However, such a survey is difficult to collect due to the high investment in time associated with data collection and the sensitive nature of the types of questions that may be asked. To overcome these limitations, the dissertation presents a new, content-based method for automated discovery of social networks from threaded discussions, referred to as ‘name network’. As a case study, the proposed automated method is evaluated in the context of online learning communities. The results suggest that the proposed ‘name network’ method for collecting social network data is a viable alternative to costly and time-consuming collection of users’ data using surveys. The study also demonstrates how social networks produced by the ‘name network’ method can be used to study online classes and to look for evidence of collaborative learning in online learning communities. For example, educators can use name networks as a real time diagnostic tool to identify students who might need additional help or students who may provide such help to others. Future research will evaluate the usefulness of the ‘name network’ method in other types of online communities.

On dangers to rational exploitation and development of the resources of the great lakes of Africa

The major dangers facing the resources of the Great Lakes of Africa include over exploitation, falling species diversity, accumulating pollution, and a probable decline in fishery productivity. These dangers may be viewed as accentuated by: i) Inadequate scientific knowledge on the exploited resources ii) Reluctance to apply even the limited scientific information available, by fishery administrators iii) Constant increase in the demand for fish and other aquatic resources. iv) Lack of commitment to active collaboration and co-operation by riparian states regarding development and management of the shared resources. This paper discusses the above factors in relation to the dangerous trends facing the resources of the Great Lakes of Africa. The discussion is intended to contribute to the promotion of rational and sustainable utilisation of the aquatic resources of these lakes.

The exploitation of small pelagic fishes of the great lakes of Africa with reference to the mukene (Rastrineobola argentea) fishery of the northern waters of Lake Victoria

Small pelagic fish species have ultimately become important on most of the Great Lakes of Africa, especially after the depletion of the larger, initially preferred fish species. In Lake Victoria, the small pelagic cyprinid Rastrineobola argentea is now the only abundant native species supporting a fast growing light fishery. In Pilkington Bay, off Lingira Island the artisanal light fishery is well established and in the last two years this bay has witnessed a sharp increase in the fishing effort. This has been followed by a modification of fishing method and a reduction in the mesh size of nets used. R. argentea now caught from this bay consist of mainly juveniles and this could result into localized recruitment overfishing. Drawing examples from what is happening to the fishery in Pilkington Bay, it is necessary to carry out research on the stocks, gear and suitable fishing crafts before light fishing spreads to most parts of the lake.

Eco-Taxonomic Insights into Actinomycete Symbionts of Termites for Discovery of Novel Bioactive Compounds

Termites play a major role in foraging and degradation of plant biomass as well as cultivating bioactive microorganisms for their defense. Current advances in "omics'' sciences are revealing insights into function-related presence of these symbionts, and their related biosynthetic activities and genes identified in gut symbiotic bacteria might offer a significant potential for biotechnology and biodiscovery. Actinomycetes have been the major producers of bioactive compounds with an extraordinary range of biological activities. These metabolites have been in use as anticancer agents, immune suppressants, and most notably, as antibiotics. Insect-associated actinomycetes have also been reported to produce a range of antibiotics such as dentigerumycin and mycangimycin. Advances in genomics targeting a single species of the unculturable microbial members are currently aiding an improved understanding of the symbiotic interrelationships among the gut microorganisms as well as revealing the taxonomical identity and functions of the complex multilayered symbiotic actinofloral layers. If combined with target-directed approaches, these molecular advances can provide guidance towards the design of highly selective culturing methods to generate further information related to the physiology and growth requirements of these bioactive actinomycetes associated with the termite guts. This chapter provides an overview on the termite gut symbiotic actinoflora in the light of current advances in the "omics'' science, with examples of their detection and selective isolation from the guts of the Sunshine Coast regional termite Coptotermes lacteus in Queensland, Australia.

Study of the development and evolution of seasonal thermocline and turbulent processes in the northern parts of Persian Gulf using numerical modeling

The Persian Gulf (PG) is a semi-enclosed shallow sea which is connected to open ocean through the Strait of Hormuz. Thermocline as a suddenly decrease of temperature in subsurface layer in water column leading to stratification happens in the PG seasonally. The forcing comprise tide, river inflow, solar radiation, evaporation, northwesterly wind and water exchange with the Oman Sea that influence on this process. In this research, analysis of the field data and a numerical (Princeton Ocean Model, POM) study on the summer thermocline development in the PG are presented. The Mt. Mitchell cruise 1992 salinity and temperature observations show that the thermocline is effectively removed due to strong wind mixing and lower solar radiation in winter but is gradually formed and developed during spring and summer; in fact as a result of an increase in vertical convection through the water in winter, vertical gradient of temperature is decreased and thermocline is effectively removed. Thermocline development that evolves from east to west is studied using numerical simulation and some existing observations. Results show that as the northwesterly wind in winter, at summer transition period, weakens the fresher inflow from Oman Sea, solar radiation increases in this time interval; such these factors have been caused the thermocline to be formed and developed from winter to summer even over the northwestern part of the PG. The model results show that for the more realistic monthly averaged wind experiments the thermocline develops as is indicated by summer observations. The formation of thermocline also seems to decrease the dissolved oxygen in water column due to lack of mixing as a result of induced stratification. Over most of PG the temperature difference between surface and subsurface increases exponentially from March until May. Similar variations for salinity differences are also predicted, although with smaller values than observed. Indeed thermocline development happens more rapidly in the Persian Gulf from spring to summer. Vertical difference of temperature increases to 9 centigrade degrees in some parts of the case study zone from surface to bottom in summer. Correlation coefficients of temperature and salinity between the model results and measurements have been obtained 0.85 and 0.8 respectively. The rate of thermcline development was found to be between 0.1 to 0.2 meter per day in the Persian Gulf during the 6 months from winter to early summer. Also it is resulted from the used model that turbulence kinetic energy increases in the northwestern part of the PG from winter to early summer that could be due to increase in internal waves activities and stability intensified through water column during this time.

GC-MS Analysis, Antimicrobial and Antioxidant Activities of Extracts of the Aerial Parts of Conyza sumatrensis

Phytochemical analyses as well as antimicrobial and antioxidant activities of the extracts of C. sumatrensis aerial parts were investigated in this study. METHODS: The aerial parts of C. sumatrensis were air dried, weighed and exhaustively extracted with hexane, ethyl acetate and methanol successively. The crude extracts were screened for metabolites. These extracts of the plant were evaluated for antimicrobial and antioxidant activities using agar diffusion and DPPH method respectively. The extracts were also analysed using Gas chromatography – Mass spectrometry, and the chromatogram coupled with mass spectra of the compounds were matched with a standard library. RESULTS: Preliminary phytochemical investigation of crude n-hexane, ethyl acetate and methanol extracts of the aerial parts of Conyza sumatrensis revealed the presence of anthraquinones, flavonoids, terpenoids, phenolics, tannin, glycosides and carbohydrate. All the crude extracts gave a clear zone of inhibition against the growth of the test bacteria ( Staphylococcus aureus , Escherichia coli , Bacillus subtilis , Pseudomona aeruginosa, Salmonella typhi , Klebsiellae pneumonae ) at moderate to high concentrations, as well as test fungi ( Candida albicans , Aspergillus niger , penicillium notatum and Rhizopus stolonifer ) at high concentration. Methanolic extract exhibited significant radical scavenging property with IC50 of 17.08 μg/mL while n-hexane and ethyl acetate extracts showed no significant antioxidant activity. GC-MS of N-hexane extract showed a total number of eleven chemical constituents with α-Farnesene and spathulenol being the most abundance compounds constituting 20.27 and 22.28% of the extract respectively. Ethyl acetate extract revealed thirteen compounds with two most abundant compounds, cis-β-farnesene (16.64 %) and cis-pinane (21.09 %). While methanolic extract affords seventeen compounds with Ephytol being the most abundant compound (19.36 %).

THE AGING OF AFRICA: CHALLENGES TO AFRICAN DEVELOPMENT

The purpose of this brief discussion is to highlight issues of demographic changes associated with an aging population in Africa and what, I believe, must happen to avoid the next social crisis among African nations.

Evaluation of the environmental benefits of recycling materials in the moving parts of a wind turbine using the life cycle assessment (LCA)

Wind energy is evaluated positively, from the environmental point of view, considering the wind a renewable resource to produce electricity, avoiding the use of fossil resources during operation, but not much has been studied about the impacts associated with the materials of the wind turbines. This study aims to contribute to an improved understanding of the environmental implications of the materials in the moving parts of a wind turbine and how the Eco strategies as recycling are increasingly adopted to ensure the minimization of environmental impacts. First, we investigate the moving parts of a wind turbine highlighting possible hot spots of impacts. Second, we assess the benefit of introducing recycling materials instead of the originals. © Research India Publications.

The waves, parts 1 and 2

This two-part video installation, exploring the feminine gaze and the traditions of cinema, was exhibited at the Institute of Modern Art in Brisbane as part of the 2013 'Fresh Cut' program.

Some fungal infestations of dried fishes in Cochin markets

Dried fish constitutes a regular item of trade in India, particularly in the interior parts far away from the sea and rivers. The poor section of the society is the main consumer. The quality of dried fish never receives much attention at any stage of processing (drying) and storage. A good amount of these fish is discarded during drying due to fungal growth to avoid the danger of mycotoxin production. A survey of the dried fish from the Cochin markets had revealed that they do carry fungal infestations and their chances of mycotoxin production cannot be ruled out as the strains of Aspergillus flavus, Aspergillus ochraceus and Fusarium spp. have been isolated.

A high resolution 15,600-year pollen and microcharcoal record from the Cederberg Mountains, South Africa

The Cederberg Mountains (Western Cape Province, South Africa) are located within the Fynbos Biome, which exhibits some of the highest levels of species richness and endemism in the world. The region's post-glacial vegetation history, however, remains largely unknown. Presented here are high resolution pollen and microcharcoal records spanning the last 15,600 years obtained from the De Rif rock hyrax midden from the Driehoek Valley of the central Cederberg. In this region, previous pollen studies have shown muted variability in vegetation community composition during periods of globally marked climatic variability (e.g. the last glacial-interglacial transition). In our record, however, significant changes in vegetation composition are apparent. Most notably, they indicate a shift from ericaceous/restioid fynbos (present from 15,600 to 13,300 cal yr BP) to a brief, but prominent, development of proteoid fynbos at the beginning of the Holocene around 11,200 cal yr BP. This vegetation shift is associated with increased moisture at the site, and coincides with reduced fire frequency as indicated by the microcharcoal record. At 10,400 cal yr BP, there is a marked reduction in Protea-type pollen, which is replaced by thicket, characterised by Dodonaea, which became the dominant arboreal pollen type. This shift was likely the result of a long relatively fire-free period coupled with warmer and wetter climates spanning much of the early Holocene. A brief but marked decrease in water availability around 8500-8000 cal yr BP resulted in the strong decrease of Dodonaea pollen. The vegetation of the mid- to late Holocene is characterised by the increased occurrence of Asteraceae and succulent taxa, suggesting substantially drier conditions. These data give unprecedented insight into the vegetation dynamics across a period of substantial, rapid climate change, and while they confirm the presence of fynbos elements throughout the last 15,600 years, the results highlight significant fluctuations in the vegetation that were triggered by changes in both climate and fire regimes. (C) 2013 Elsevier B.V. All rights reserved.

Multiple mycotoxin exposure determined by urinary biomarkers in rural subsistence farmers in the former Transkei, South Africa

Subsistence farmers are exposed to a range of mycotoxins. This study applied novel urinary multi-mycotoxin LC-MS/MS methods to determine multiple exposure biomarkers in the high oesophageal cancer region, Transkei, South Africa. Fifty-three female participants donated part of their maize-based evening meal and first void morning urine, which was analysed both with sample clean-up (single and multi-biomarker) and by a 'dilute-and-shoot' multi-biomarker method. Results were corrected for recovery with LOD for not detected. A single biomarker method detected fumonisin B1 (FB1) (87% incidence; mean±standard deviation 0.342±0.466 ng/mg creatinine) and deoxynivalenol (100%; mean 20.4±49.4 ng/mg creatinine) after hydrolysis with β-glucuronidase. The multi-biomarker 'dilute-and-shoot' method indicated deoxynivalenol-15-glucuronide was predominantly present. A multi-biomarker method with β-glucuronidase and immunoaffinity clean-up determined zearalenone (100%; 0.529±1.60 ng/mg creatinine), FB1 (96%; 1.52±2.17 ng/mg creatinine), α-zearalenol (92%; 0.614±1.91 ng/mg creatinine), deoxynivalenol (87%; 11.3±27.1 ng/mg creatinine), β-zearalenol (75%; 0.702±2.95 ng/mg creatinine) and ochratoxin A (98%; 0.041±0.086 ng/mg creatinine). These demonstrate the value of multi-biomarker methods in measuring exposures in populations exposed to multiple mycotoxins. This is the first finding of urinary deoxynivalenol, zearalenone, their conjugates, ochratoxin A and zearalenols in Transkei.

Migration, Space and Transnational Identities: The British in South Africa

This timely text explores the lives, histories and identities of white British-born immigrants in South Africa, twenty years after the post-apartheid Government took office. Drawing on over sixty in depth biographical interviews and ethnographic work in Johannesburg, Pietermaritzburg and Cape Town, Daniel Conway and Pauline Leonard analyse how British immigrants' relate to, participate in and embody South Africa's complex racial and political history. Through their everyday lives, political and social attitudes, relationships with the places and spaces of South Africa, as well as their expectations of the future, the complexities of their transnational, raced and classed identities and senses of belonging are revealed. Migration, Space and Transnational Identities makes an important contribution to sociological, geographical, political and anthropological debates on transnational migration, whiteness, Britishness and lifestyle, tourism and labour migration.