The last million years around Lake Keilambete Western Victoria Australia

© Royal Society of VictoriaPollen records from sediments preserved in the older volcanic crater maars of Lake Terang and Pejark Marsh, situated close to the more recent and intensively researched younger maar containing Lake Keilambete, provide a basis for understanding the development of the present landscape of western Victoria in relation to past vegetation evolution, climate change and volcanic activity. Despite dating uncertainties and discontinuities, the record from Lake Terang may cover much of the last five hundred thousand years (500 ka) while that from Pejark Marsh is fission track dated to between about one million years (1 Ma) and 700 ka. An analogue method is used to provide measures of past vegetation and precipitation. Overall, the Early Pleistocene vegetation was dominated by herbaceous taxa with an open canopy of trees composed of more Callitris and fewer eucalypts than today. The climate was drier, never achieving rainfall levels higher than present. Since this time the vegetation and climate displayed greater variability, probably in relation to global shifts between glacial and interglacial conditions, with interglaciat peaks often showing the development of eucalypt forest and expansion of cool temperate rainforest. Through the whole period, climate appears to have been the dominant influence on vegetation with no detectable impact of volcanic activity

A long term lake-salinity record and its relationships to Daphnia populations

Sediment cores from the shallow, presently saline, volcanic maar lake of Tower Hill were collected in March 2000, dated using 210Pb, and analysed for diatoms to infer changing salinity levels. Diatom inferred salinity was used to assess the hatching response of incorporated Daphnia ephippia. The early growth rate of Daphnia from different core depths, in media with two different salinities (0.5 g/L and 4 g/L) was also measured. Sediments have steadily accumulated in the Tower Hill basin over the past 50 years since the lake was last reported to have dried. The diatom record indicates a fairly stable salinity regime, with salt concentrations fluctuating between 1 and 2 g/L until 1990, followed by an exponential increase in salt concentrations peaking in the year 2000 at around 13 g/L. There were significant fluctuations in ephippia densities, with at least two large peaks and several periods of low ephippial accumulation. Ephippial densities were only weakly correlated with salinity changes. Maximum hatching of ephippia, all of the one species, Daphnia thomsoni, occurred in the top 7 cm of the cores, corresponding to the past 10 years. The oldest eggs to hatch were from sediments dated around 37 years old. The body length after six days growth of 19 clones, from 3 core sections (0–2cm; 2–4cm; >4cm) was measured under conditions of low salinity (0.5 g/L) and high salinity (4 g/L). Surprisingly, all but one clone reached a larger size at high salinity. However, clones from the top 2cm, which were produced during the lake's recent period of high salinity showed the strongest growth response at 4 g/L. Analysis of allozymes at three polymorphic loci did not find any evidence of genetic differentiation based on allelic frequencies. In order to assess possible reasons for differences in hatching patterns observed in cores taken in 2000, two additional cores were collected in September 2002. One showed a similar hatching pattern to the 2000 cores, and the other exhibited a more even pattern of hatching over its length.M.J. Barry, J. Tibby, A. Tsitsilas, B. Mason, P. Kershaw and H. Heijni

Zon-WEL, een innovatief gevelconcept. Ontwerp klimaatgeregelde en dynamische zonnegevel

Een betere afstemming tussen het buitenklimaat en de vraag naar verwarming of koeling zal leiden tot zowel een verlaging van het energiegebruik als verbetering van het comfort. Dit is de inzet van onderzoek dat moet leiden tot een geheel nieuw gevelconcept waarbij de installatieconcepten zoveel mogelijk in de gevel worden geintegreer

History of metal contamination in Lake Illawarra, NSW, Australia

Lake Illawarra has a long history of sediment contamination, particularly by metals, as a result of past and current industrial operations and land uses within the catchment. In this study, we examined the history of metal contamination in sediments using metal analysis and 210Pb and 137Cs dating. The distributions of copper, zinc, arsenic, selenium, cadmium and lead concentrations within sediment cores were in agreement with historical events in the lake, and indicated that metal contamination had been occurring since the start of industrial activities in Port Kembla in the late 1800s. Most metal contamination, however, has occurred since the 1960s. Sedimentation rates were found to be 0.2 cm year−1 in Griffins Bay and 0.3 cm year−1 in the centre of the lake. Inputs from creeks bringing metals from Port Kembla in the northeast of the lake and a copper slag emplacement from a former copper refinery on the Windang Peninsula were the main sources of metal inputs to Lake Illawarra. The metals of highest concern were zinc and copper, which exceeded the Australian and New Zealand sediment quality guideline values at some sites. Results showed that while historical contamination persists, current management practices have resulted in reduced metal concentrations in surface sediments in the depositional zones in the centre of the lake.© 2015, Elsevier Ltd

Neural correlates of enhanced working-memory performance in dissociative disorder: a functional MRI study

BACKGROUND: Memory functioning has been highlighted as a central issue in pathological dissociation. In non-pathological dissociation, evidence for enhanced working memory has been found, together with greater task-load related activity. So far, no imaging studies have investigated working memory in dissociative patients. METHOD: To assess working memory in dissociative patients functional magnetic resonance imaging was used during performance of a parametric, verbal working-memory task in patients with a dissociative disorder (n=16) and healthy controls (n=16). RESULTS: Imaging data showed that both groups activated brain regions typically involved in working memory, i.e. anterior, dorsolateral and ventrolateral prefrontal cortex (PFC), and parietal cortex. Dissociative patients showed more activation in these areas, particularly in the left anterior PFC, dorsolateral PFC and parietal cortex. In line with these findings, patients made fewer errors with increasing task load compared to controls, despite the fact that they felt more anxious and less concentrated during task performance. CONCLUSIONS: These results extend findings in non-pathological high dissociative individuals, suggesting that trait dissociation is associated with enhanced working-memory capacities. This may distinguish dissociative patients from patients with post-traumatic stress disorder, who are generally characterized by impaired working memor

Cardioprotective effect of trimetazidine and nifedipine in guinea-pig hearts subjected to ischaemia

The cardioprotective effects of nifedipine and trimetazidine were evaluated in the Langendorff heart, the working heart and the heart-lung preparation of the guinea-pig. The effects of pretreatment with the drugs on cardiac function and on high energy phosphate content after global ischaemia were determined. Nifedipine was 1000-fold more active than trimetazidine in depressing cardiac functional parameters. In the Langendorff heart, nifedipine, but not trimetazidine, increased the coronary flow. With the exception of trimetazidine (4 x 10-5 mol/l) in the Langendorff heart, nifedipine and trimetazidine markedly improved and in a similar fashion, the recovery of cardiac mechanical parameters in the three models of myocardial ischaemia. Pretreatment with nifedipine, but not with trimetazidine, resulted in slightly but statistically not significant higher ATP-levels after global ischaemia in the working heart and in the heart-lung preparation. After reperfusion, the cardioprotective effect of nifedipine was associated with increased ATP-levels, whereas that of trimetazidine was merely related to increased phosphocreatine (PCr) levels. In the pithed rat, trimetazidine did not influence the vasoconstrictor response to the selective α1-adrenoceptor agonist cirazoline or to the selective α2-adrenoceptor agonist B-HT 920. The latter response is known to be strongly dependent on the influx of extracellular calcium. Nifedipine caused a pronounced inhibition of vasoconstriction evoked by B-HT 920. These results indicate that trimetazidine is devoid of calcium entry blocking activity. The data obtained clearly show that trimetazidine exerts a pronounced beneficial effect on the ischaemic myocardium without influencing hemodynamic parameters. The mechanism of the cardioprotective activity of the drug is not related to calcium entry blockade or α-adrenoceptor antagonism, but rather caused by a mechanism at a cellular level, so far not known in detail