Alloimmune responses between Acropora hemprichi conspecifics: nontransitive patterns of overgrowth and delayed cytotoxicity

Allogeneic interactions between Acropora hemprichi (Ehrenberg) colonies were followed in situ up to 18 mo between 1990 and 1992 in Eilat, Red Sea. We established all 21 possible branch pair combinations among seven large colonies in three to eight replicates each (n=92 pairs), in addition in 14 pairs of grafts within-colonies. All isografts resulted in fusion. Allogeneic interactions revealed a variety of effector mechanisms which involved the appearance of dark blue-purple color in the tissues of interacting branch tips (<1 cm), unilateral overgrowths (1.0 to 1.5 mm mo^-1 for 1 to 8 mo), rejections, healings, continuous overgrowths, reversals, repeated rejections and more. Direction of overgrowth was usually specific to a given combination of colonies. A hierarchial network of overgrowths was obtained by analyzing overgrowth directions of all pairwise combinations, which included 30 transitive and five nontransitive three-way combinations. These outcomes, similarly to responses of allogeneic encounters recorded from other coral species, show that colonies can respond selectively to different types of allogeneic challenges. It is suggested that corals may have the capacity to distinguish self from nonself by recognizing nonself attributes presented on conspecifics.     

Retrospective monitoring: A review

The development of chronological reference points to which present levels of inorganic pollutants can be compared is increasingly needed. This review is directed toward biological samples which are datable and have been characterized for one or more elements.     

Life in extreme environments: survival strategy of the endolithic desert lichen Verrucaria rubrocincta

Verrucaria rubrocincta Breuss is an endolithic lichen that inhabits caliche plates exposed on the surface of the Sonoran Desert. Caliche surface temperatures are regularly in excess of 60 degrees C during the summer and approach 0 degrees C in the winter. Incident light intensities are high, with photosynthetically active radiation levels typically to 2,600 micromol/m(2) s(-1) during the summer. A cross-section of rock inhabited by V. rubrocincta shows an anatomical zonation comprising an upper micrite layer, a photobiont layer containing clusters of algal cells, and a pseudomedulla embedded in the caliche. Hyphae of the pseudomedulla become less numerous with depth below the rock surface. Stable carbon and oxygen isotopic data for the caliche and micrite fall into two sloping, well-separated arrays on a delta(13)C-delta(18)O plot. The delta(13)C(PDB) of the micrite ranges from 2.1 to 8.1 and delta(18)O(SMOW) from 25.4 to 28.9, whereas delta(13)C(PDB) of the caliche ranges from -4.7 to 0.7 and delta(18)O(SMOW) from 23.7 to 29.2. The isotopic data of the micrite can be explained by preferential fixing of (12)C into the alga, leaving local (13)C enrichment and evaporative enrichment of (18)O in the water. The (14)C dates of the micrite range from recent to 884 years b.p., indicating that "dead" carbon from the caliche is not a significant source for the lichen-precipitated micrite. The endolithic growth is an adaptation to the environmental extremes of exposed rock surfaces in the hot desert. The micrite layer is highly reflective and reduces light intensity to the algae below and acts as an efficient sunscreen that blocks harmful UV radiation. The micrite also acts as a cap to the lichen and helps trap moisture. The lichen survives by the combined effects of biodeterioration and biomineralization. Biodeterioration of the caliche concomitant with biomineralization of a protective surface coating of micrite results in the distinctive anatomy of V. rubrocincta.     

Development and pilot testing of an assessment battery for older drivers

INTRODUCTION: The purpose of the study reported here was to develop and pilot test a comprehensive battery of assessment instruments for older drivers that would be inexpensive and easy to administer so that it could be used in longitudinal studies. METHOD: The resulting battery was developed by selecting a set of validated assessment instruments and combining them into a package, with a total acquisition cost of less than $900. As part of this battery, three questionnaires were developed utilizing items from established questionnaires with minor modifications. The battery was pilot tested with a convenience sample of 38 drivers aged 65 years or older. RESULTS: Results showed that the entire battery required less than one hour to complete. Data from the assessment outcomes fell within normative ranges. Feedback from subjects indicated that the battery was acceptable, free of problems, presented tasks in a good order, and was not too long. CONCLUSIONS: Based on study findings, the assessment battery appeared to be low-cost, transportable, easy to administer, easy for subjects to complete, provides a comprehensive assessment of a person's physical health, mental health, and driving behaviors, and would serve as a valuable data collection tool for a longitudinal study of older drivers. Such a longitudinal study is needed in order to answer some of the most important questions about older driver safety and mobility.     

Atlantic sturgeons (<Emphasis Type="Italic">Acipenser sturio</Emphasis>, <Emphasis Type="Italic">Acipenser oxyrinchus</Emphasis>): American females successful in Europe

Recent molecular data on the maternally inherited mitochondrial (mt) DNA have challenged the traditional view that the now extinct Baltic sturgeon population belonged to the European sturgeon Acipenser sturio. Instead, there is evidence that American sea sturgeon Acipenser oxyrinchus historically immigrated into the Baltic Sea. In this study, we test the hypothesis that A. oxyrinchus introgressed into, rather than replaced, the A. sturio population in the Baltic. We established four single nucleotide polymorphisms (SNPs) in the nuclear MHC II antigen gene with a species-specific SNP pattern. Using an ancient DNA approach and two independent lines of molecular evidence (sequencing of allele-specific clones, SNaPshot), we detected both A. sturio and A. oxyrinchus alleles in the available museum material of the now extinct Baltic sturgeon population. The hybrid nature of the Baltic population was further confirmed by very high levels of heterozygosity. It had been previously postulated that the immigration of the cold-adapted A. oxyrinchus into the Baltic occurred during the Medieval Little Ice Age, when temperature likely dropped below the degree inducing spawning in A. sturio. Under this scenario, our new findings suggest that the genetic mosaic pattern in the Baltic sturgeon population (oxyrinchus mtDNA, sturio and oxyrinchus MHC alleles) is possibly caused by sex-biased introgression where spawning was largely restricted to immigrating American females, while fertilization was predominantly achieved by abundant local European males. The hybrid nature of the former Baltic sturgeon population should be taken into account in the current reintroduction measures. Electronic supplementary material  Supplementary material is available in the online version of this article at and is accessible for authorized users.     

Applying the multi-level perspective on socio-technical transitions to rentier states: the case of renewable energy transitions in Nigeria

Although numerous studies have been conducted in recent years on energy transitions, they have been predominately developed and applied in industrialized countries. It is however important to examine the applicability of transition theories, as they are currently formulated, beyond OECD countries. This paper analyses renewable energy transitions in Africa, using Nigeria as a case study, to elucidate the analytical and methodological challenges that sustainability transition studies are facing in developing countries, particularly rentier states. In doing so, the paper employs the lens of the multi-level perspective (MLP) on socio-technical transitions - a well-established theory that emphasizes the role of ‘niches’, ‘regimes’ and ‘landscapes’ in instituting transitions. Based on a detailed analysis of Nigeria, we argue for a more nuanced enquiry of the construct ‘regime’ that better accounts for the rentier character of the state including the role of political elites and prevalent client-patron relationships. As such, our paper makes an important contribution to the further refinement and enrichment of the MLP by focusing on the political dimensions of energy transitions.     

Leaching of copper,chromium and arsenic in a soil of south west Victoria,Australia

The movement of copper, chromium and arsenic originating from samples of the wood preservative Tanalith® through mildly acidic, sandy loam soil was investigated. Small, undisturbed soil cores (of dimensions 15 × 15 × 15 cm) were removed from the topsoil of a paddock adjacent to the Glenelg River in the Western District of Victoria, Australia. The paddock soils were thin (<30cm) greyish brown, mildly acidic, sandy loams with a moderate organic carbon content (2–5%) overlying a limestone cap. Tanalith® was applied to the surface of the cores which were then irrigated with deionised water at approximately 30 mm day^‐1. Copper concentrations in all leachate remained at background levels throughout the experiment, and this element was found to be immobilised in the top 4 cm of the soil. Up to 29% of the applied dose of chromium was detected in the leachate, with breakthrough occurring within 20 days of Tanalith® application. Up to 13% ofthe applied dose ofarsenic was detected in the leachate, although in this case breakthrough was not observed until 25 days after Tanalith® application and leachate concentrations were still rising when the experiment came to a close. Significant concentrations of arsenic and chromium were found in the top 6 cm of the soil profile.     

Environmental fate of pesticides used in Australian viticulture IV. Aqueous stability of dithianon

Dithianon formulations are unstable in slightly basic aqueous solutions (pH 9, 20°C, t _½ = 5.6 h) but relatively stable in neutral or acidic solution (pH 4,20°C, t _½ = 6443 h). To ensure the efficacy of this fungicide it is important to prepare the spray mix fresh with neutral or slightly acidic water. Dithianon is unstable towards natural sunlight in the solid and aqueous phase, with half‐lives of approximately 68 and 42 days, respectively. Thermal hydrolysis does not seem to be the preferred degradation pathway when aqueous solutions are heated by the South Australian summer sun. The major aqueous phase photodegradation product has been identified as 2,3‐dihydro‐1,4‐dithiaanthraquinone. These results strongly suggest that should dithianon be accidentally released into basic Australian waters then it is likely to be rapidly chemically hydrolysed and pose little long term environmental threat. However, dithianon is only slowly chemically and photo‐lytically hydrolysed in neutral and acidic waters, and in this case accidentally release may pose a significant short term environmental threat.