ALBERT

Description: The Sarulla graben is a composite Plio-Pleistocene basin developed along the northwest striking, dextral-slip Sumatra fault in a region where the fault coincides with the Sumatra volcanic arc. Offset of the 0.27±0.03 Ma Tor Sibohi rhyodacite dome by an active strand of the Sumatra fault, the Tor Sibohi fault (TSF), indicates a slip rate of about 9 mm/y. This value is lower than previous regional estimates of ∼25–30 mm/y for Holocene slip on the Sumatra fault determined from stream offsets in the Taratung region. This discrepancy may be due to (1) a difference between Holocene and late Quaternary rates of slip and (2) additional slip on other faults in the Sarulla area. Since the magnitude of undated stream offsets along the TSF in the Sarulla area is similar to those in the Taratung area, the discrepancy is likely to be due largely to a change in slip rate over time. Within the Sarulla area, major volcanic centers include the Sibualbuali stratavolcano (∼0.7–0.3 Ma), the Hopong caldera (∼1.5 Ma), and the Namora-I-Langit dacitic dome field (0.8–0.1 Ma). These centers generated the majority of the ash-flow tuffs and tuffaceous sediments filling the Sarulla graben, and appear to have been localized by structural features related to the Sumatra fault zone. Four geothermal systems within the Sarulla area are closely linked to major faults and volcanic centers. In three of the systems, reservoir permeability is clearly dominated by specific structures within the Sumatra fault system. In the fourth geothermal system, Namora-I-Langit geothermal field, permeability may be locally influenced by faults, but highly permeable fractures are widely distributed.

Description: The electric generating capacity of Turkey must be tripled by 2010 to meet Turkey’s electric power consumption, if the annual 8% growth in electric power consumption continues. Turkey has to make use of its renewable energy resources, such as wind and solar, not only to meet the increasing energy demand, but also for environmental reasons. Studies show that Iskenderun (36°35′N; 36°10′E) located on the Mediterranean coast of Turkey is amongst the possible wind energy generation regions. In the present study, the wind energy potential of the region is statistically analyzed based on 1-year measured hourly time-series wind speed data. The probability density distributions are derived from time-series data and distributional parameters are identified. Two probability density functions are fitted to the measured probability distributions on a monthly basis. The wind energy potential of the location is studied based on the Weibull and the Rayleigh models.

Description: Using contemporary CO2 data from the subsurface Weddell Sea, the source/sink function of this region against the changing atmospheric CO2 level has been investigated. As in the central Weddell Sea, surface water is supplied by upwelling of subsurface water, the CO2 content is also forced by it. TCO2 data of four cruises were used to determine a robust value for the subsurface Warm Deep Water (WDW). After accounting for biological activity in the surface layer and salinity differences between the subsurface and surface waters, the forcing CO2 partial pressure (pCO2) was calculated from the TCO2 of the WDW and the conservative alkalinity as taken from the literature. As the WDW contains negligible anthropogenic CO2, the pCO2 forcing by the WDW has been prevalent both in the pre-industrial and modern Weddell Sea. The calculated pCO2 forcing amounts to 300–310 μatm at a minimum in late winter/early spring and possibly 30 μatm more during spring and summer. This figure does not represent the actual pCO2, but rather the value before air–sea exchange gets effective. Hence, in pre-industrial times when the atmospheric pCO2 was about 280 μatm, the Weddell Sea must have been a relatively strong source of atmospheric CO2. Because of the steadily rising atmospheric CO2 levels to more than the pCO2 forcing by the WDW, the Weddell Sea turned into a CO2 sink in recent times. The storage of anthropogenic CO2 in the Weddell Sea surface layer is estimated to be 4.1 mol C m−2. Applying the WDW forcing method to O2, a steady state O2 uptake from the atmosphere of 3.6 mol O2 m−2 year−1 is computed.

Description: We provide an overview of the basic concepts of scaling and dimensional analysis, followed by a review of some of the recent work on applying these concepts to modeling instrumented indentation measurements. Specifically, we examine conical and pyramidal indentation in elastic–plastic solids with power-law work-hardening, in power-law creep solids, and in linear viscoelastic materials. We show that the scaling approach to indentation modeling provides new insights into several basic questions in instrumented indentation, including, what information is contained in the indentation load–displacement curves? How does hardness depend on the mechanical properties and indenter geometry? What are the factors determining piling-up and sinking-in of surface profiles around indents? Can stress–strain relationships be obtained from indentation load–displacement curves? How to measure time dependent mechanical properties from indentation? How to detect or confirm indentation size effects? The scaling approach also helps organize knowledge and provides a framework for bridging micro- and macro-scales. We hope that this review will accomplish two purposes: (1) introducing the basic concepts of scaling and dimensional analysis to materials scientists and engineers, and (2) providing a better understanding of instrumented indentation measurements.

Description: A search for antibacterial activity in different organs/tissues of the horse mussel, Modiolus modiolus, was conducted. Dried samples were extracted with 60% (v/v) acetonitrile, containing 0.1% (v/v) trifluoroacetic acid. Due to high salt content, two liquid phases were obtained; an acetonitrile-rich phase (ACN extract) and an aqueous phase. The aqueous phase was further subjected to solid phase extraction (SPE). Eluates from SPE and ACN extracts were tested for antibacterial, lysozyme, and toxic activity. Antibacterial activity was demonstrated in extracts from several tissues, including plasma, haemocytes, labial palps, byssus, mantle, and gills. Some of the extracts were sensitive to proteinase K treatment, indicating antibacterial peptides and/or proteins. Lysozyme-like activity and toxic activity against Artemia salina nauplii was detected in fractions from the gills, mantle, muscle, and haemocytes. Results from this study indicate that M. modiolus is a promising source for identifying novel drug lead compounds.

Description: Eclogites from the Earth's mantle found in kimberlites provide important information on craton formation and ancient geodynamic processes because such eclogites are mostly Archean in age. They have equilibrated over a range of temperatures and pressures throughout the subcratonic mantle and some are diamond-bearing. Most mantle eclogites are bimineralic (omphacite and garnet) rarely with accessory rutiles. Contrary to their overall mineralogical simplicity, their broadly basaltic-picritic bulk compositions cover a large range and overlap with (but are not identical to) much younger lower grade eclogites from orogenic massifs. The majority of mantle eclogites have trace element geochemical features that require an origin from plagioclase-bearing protoliths and oxygen isotopic characteristics consistent with seawater alteration of oceanic crust. Therefore, most suites of eclogite xenoliths from kimberlites can be satisfactorily explained as samples of subducted oceanic crust. In contrast, eclogite xenoliths from Kuruman, South Africa and Koidu, Sierra Leone stem from protoliths that were picritic cumulates from intermediate pressures (1–2 Ga) and were subsequently transposed to higher pressures within the subcratonic mantle, consistent with craton growth via island arc collisions. None of the eclogite suites can be satisfactorily explained by an origin as high pressure cumulates from primary melts from garnet peridotite.

Description: Three tephra layers have been identified in the upper 15 m of a 190-m section of peat beneath the Philippi fen. They provide significant lithological and chronological markers throughout the fen and the Aegean region. The upper tephra (PhT1) consists of shards of a transparent calcalkaline felsic glass and fragments of plagioclase, augite, hypersthene, and rare hornblende, magnetite, apatite and quartz. Peat directly beneath PhT1 gave a radiocarbon approximate age of 13,000 yr. The middle tephra layer (PhT2), which resembles PhT1 in chemistry and petrography but contains more crystals and lithic fragments, rests on peat dated ca 18,000 14C yr BP. The lower tephra (PhT3) has colorless to brown glass shards with a trachytic chemistry and a mineral assemblage of sanidine, sodic plagioclase, biotite, aegirine-augite, hornblende, titanite and apatite. Bracketing radiocarbon ages imply that PhT3 accumulated about ∼30,000 14C yr BP. The likely ages of PhT1 and PhT2, together with their mineralogical and chemical characteristics, suggest that these tephras came from the volcanic field of Thera in the Hellenic arc. PhT2 particularly was derived from a major, known explosive eruption ca 18,000 yr BP, the Cape Riva eruption, correlative to the Y-2 tephra layer. Evidence for PhT3 suggests derivation from the Campanian Province of Italy, and correlation with the Campanian Ignimbrite and the Y-5 ash beneath the Mediterranean Sea.

Description: The purpose of this study was to establish a bioassay from isolated digestive gland cells of the cuttlefish Sepia officinalis in order to observe the effect of heavy metals on digestive enzyme activities. Digestive cells were isolated using a pronase enzyme that was removed by several washings of the cell suspension. Cell viability was tested by the MTT assay (3-4,5-dimethylthiazol-2-yl-2,5-diphenyl tetrazolium) and microscopic analysis. The results showed that isolated digestive cells could be maintained 24 h with preservation of whole digestive functionality, measured in terms of MTT test. In fact, the viability was maintained at a high level during 24 h and the intra- and extracellular digestive enzyme activities became stabilised rapidly. Furthermore, suspension cells responded to calcium ionophore and 8-Bromo-cAMP by an unspecific secretion of extracellular digestive enzyme, trypsin, which demonstrated that isolated digestive cells were functional. Using the bioassay, ecotoxicological studies showed that heavy metals could have effects on digestive enzyme activities after 24 h of an incubation time of the metal with the cells. In fact, zinc and silver affected trypsin and/or cathepsins specific activity of the cells. On the contrary, copper had no effect on digestive enzyme activities. Zinc, which is a trace element in all living animals, generated two different responses of cathepsins and cell viability. At a low concentration (0.02 μM), it increased viability and cathepsins specific activity, whereas at a high concentration (0.02 mM), zinc inhibited the cathepsins specific activity with an inhibition of cathepsins. For silver, whatever the tested concentration (0.02 mM or 0.02 μM), it has no impact on digestive gland isolated cell viability. Nevertheless, heavy metal induced high disturbance of enzymatic systems.

Description: Hatchlings cuttlefish were reared in the laboratory from hatching until 30 days old, fed with live shrimp, frozen shrimp or fish oil-enriched frozen shrimp. Survival of cuttlefish fed with oil-enriched frozen shrimp was better than in animals receiving live shrimp. However, there was no difference with cuttlefish fed with frozen shrimp, even if survival of those receiving oil-enriched frozen shrimp was always higher all along the experiment. Lower survival in animals fed with live shrimp represented the problem of using such food and confirms the necessity to elaborate an artificial food. Utilization of artemia was detrimental to growth and induced low values of instantaneous growth rate (IGR) and conversion rate even after feeding cuttlefish with shrimp. Nevertheless, growth parameters evolutions generally corresponded to those observed by other researchers. The profile noticed at the end of the experiment is typically observed when cuttlefish acquire their adult digestive system. Main differences were observed between groups fed with live shrimp or oil-enriched frozen shrimp. Enrichment did not induce same growth as in cuttlefish receiving live prey. However, at 20 and 25 days after hatching (DAH), in cuttlefish fed with oil-enriched frozen shrimp, ration was lower for the same growth than in other groups. These data showed capacity of juvenile cuttlefish to adjust their digestive enzyme activities according to the diet and the stage of development. Indeed, chymotrypsin was strongly influenced by enrichment, while other enzymes showed difference between live and frozen preys. Trypsin exhibited regulation by diet after 20 DAH. Freezing seemed to delay development as acid phosphatases, characteristic of first stages of cuttlefish, had lower activity in cuttlefish fed with live shrimp at 10 DAH. Moreover, influence of the stage of development was strong as activities between 20 and 30 DAH were different in all groups. This was in relation with evolution of the digestive system. These data illustrated the difficulty to elaborate optimal diet as digestive system evolves.