Gas in early-type galaxies: cross-fuelling in late-type–early-type pairs?

We present  ¹²CO ( J = 1–0)  and  ¹²CO ( J = 2–1)  observations of eight early-type galaxies, forming part of a sample of interacting galaxies, each consisting of one late- and one early-type system. All of the early-type galaxies observed are undetected in CO to low levels, allowing us to place tight constraints on their molecular gas content. Additionally, we present H  i absorption data for one system. The implications for possible gas transfer from the late- to the early-type galaxy during the interaction are discussed.     

RAM-Pressure Stripping of a Galaxy's ISM

NGC 4485 is a late-type galaxy moving through the very extended HI envelope of its companion, NGC 4490. NGC 4485 is undetected in HI,CO and IRAS wavebands, but a peak at all of these frequencies is seen displaced from the optical disk. HI data show a prominent bow-shock ahead of this displaced gas. It is argued that almost the entire ISM, including molecular clouds, has been stripped from this galaxy byram-pressure, and that it will emerge from the encounter with very little star forming potential. This revised version was published online in July 2006 with corrections to the Cover Date.     

Quaternary palaeoceanographic changes in the northern South China Sea (ODP Site 1146): radiolarian evidence

The abundance and accumulation rates of siliceous microfossils in the northern South China Sea, including radiolarians, diatoms and sponge spicules, increased during most glacial intervals within the past 1100 kyr. Similar trends are observed in the index of thermocline surface radiolarians (TSR), diatom accumulation rates (DAR), charcoal accumulation rates (CAR) and the abundance of radiolarian species Cycladophora davisiana davisiana. Decreasing sea‐surface temperature accompanied by increased seasonality since 900 ka is indicated by a decline in the tropical radiolarian assemblage, including Tetrapyle octacantha and Octopyle stenozona, and by an increase in the subtropical assemblage, including Pterocorys zancleus, Peromelissa phalacra and Ommatartuts tetrathalamus tetrathalamus. Rapid increases at about 800 to 700 ka of siliceous microfossils, charcoal, subsurface and intermediate radiolarians, as well as the TSR index and the DAR, imply a fundamental shift in climate and a shoaling thermocline. Although these fundamental changes in the silicious fauna and flora of the South China Sea take place within the context of a developing 100‐kyr cycle, they do not change in step with changing sea‐level as indicated by marine δ¹⁸O. This is most clearly illustrated by the step‐like increase in silica accumulation (radiolaria, diatoms and sponge spicules) at 680 ka. Rather, these fundamental changes probably reflect intensified surface productivity associated with enhanced East Asian winter‐monsoon circulation. Copyright © 2003 John Wiley & Sons, Ltd.     

A sequential ensemble prediction system at convection-permitting scales

A sequential data assimilation approach (SAM) that incorporates elements of particle filtering with resampling (SIR, Sequential Importance Resampling) is introduced. SAM is applied to the COSMO-DE-EPS, which is an ensemble prediction system for weather forecasting on convection-permitting scales. At the convective scale and beyond, the atmosphere increasingly exhibits non-linear state space evolutions. For an ensemble-based data assimilation system, this requires both an adequate metric that quantifies the distance between the observed atmospheric state and the states simulated by the ensemble members, and a methodology to counteract filter degeneracy, i.e. the collapse of the simulated state space. We, therefore, propose a combination of resampling, which accounts for simulated state space clustering, and nudging. SAM differs from the classical SIR approach mainly in the weighting applied to the ensemble members. By keeping cluster representatives during resampling, the method maintains the potential for non-linear system state development. With three convective case studies, we demonstrate that SAM improves forecast quality compared with the control EPS (EPS without data assimilation) for the first 5–6 h of forecast.     

Temperature-dependent leaching of chemical elements from mineral water bottle materials

It is well established that minute amounts of chemical elements will leach from bottle materials (glass or PET – polyethylene terephthalate) to water stored in such bottles. This study investigated whether leaching increases with storage temperature. For glass bottles this is clearly the case for a long list of elements: Ag, Al, As, B, Ba, Ca, Co, Cr, Cs, Cu, Fe, Ga, Ge, K, La, Li, Mg, Mo, Na, Ni, Pb, Rb, Sb, Se, Sn, Sr, Ti, U, V, W and Zr. However, for glass bottles drinking water maximum admissible concentration values as defined by European authorities are not exceeded even after 1 week of leaching at 80 °C. The critical temperature limit where leaching substantially increases for many elements appears to be 45 °C. For PET bottles, Sb is the only element where leaching is observed at all temperatures and again leaching strongly increases at 45 °C. For PET bottles Sb concentrations observed in water after 1 week storage at 80 °C reach almost four times the maximum admissible concentration values for drinking water but do not exceed the relevant higher limit for food (including water) packaged in PET.     

Quaternary clay mineralogy in the northern South China Sea (ODP Site 1146)

Measurement of clay mineralogy at ODP Site 1146 in the northern South China Sea (SCS) indicates that illite, chlorite, and kaolinite contents increased during glacials and smectite content increased during interglacials. The smectite/(illite+chlorite) ratio and the smectite abundance were determined as mineralogical indicators for the East Asian monsoon evolution. At a 10 ka timescale, prevailing southeasterly surface oceanic currents during interglacials transported more smectite from the south and east areas to the north, showing a strengthened summer monsoon circulation, whereas dominated counter-clockwise surface currents during glacials carried more illite and chlorite from Taiwan as well as from the Yangtze River via the Luzon Strait to the northern SCS, indicating a strongly intensified winter monsoon. Based on a 100 ka timescale, a linear correlation between the smectite/(illite+chlorite) ratio and the sedimentation rate reflects that the winter monsoon has prevailed in the northern SCS in the intervals 2000–1200 ka and 400–0 ka and the summer monsoon did the same in the interval 1200–400 ka. The evolution of the summer monsoon provides an almost linear response to the summer insolation of Northern Hemisphere, implying an astronomical forcing of the East Asian monsoon evolution.     

A fish-based typology of small temperate rivers in the northeastern lowlands of Germany

Fish assemblage data from 69 brooks and small streams were analysed to derive a fish-based typology of small lowland streams in the “Central Plains” ecoregion of northeastern Germany. Altogether 32 native, 1 non-native fish species and 2 lamprey species were detected in the lowland rivers studied. Species number and diversity varied significantly according to mean summer water temperatures and size of the watercourses. Summer-cold brooks contained on average 3-5 species, brooks with higher summer temperatures 5-8 species and small lowland rivers around 10-14 species. Small lowland brooks contained a significantly higher number of fish species when they flowed into or out of lakes: typically around 8-12.In the northeastern German lowlands the following three different river types were distinguished according to their fish assemblages: (1) The “lowland trout brook”, where brown trout (Salmo trutta L.) are reference species and accompanied by stone loach (Barbatula barbatula (L.)), brook lamprey (Lampetra planeri (Bloch)), three-spined stickleback (Gasterosteus aculeatus L.), ten-spined stickleback (Pungitius pungitius (L.)) and gudgeon (Gobio gobio (L.)); (2) The “perch- and roach-dominated lowland brook”, where perch (Perca fluviatilis L.) and roach (Rutilus rutilus (L.)) are reference species, accompanied by pike (Esox lucius L.), three-spined stickleback and gudgeon; and (3) The “lowland lake connected brook” inhabited by higher numbers of fish species, with higher proportions of cyprinid fishes, and higher proportions of limnophilic fish. Apart from perch and roach, bleak (Alburnus alburnus (L.)), common bream (Abramis brama (L.)), silver bream (Blicca bjoerkna (L.)) and rudd (Scardinius erythrophthalmus (L.)) also occurred frequently.Further two observed fish-based types were not considered: The potential stone loach-dominated brook was not sufficiently represented in this study to be verified, and the stickleback brook was considered to represent degradation of lowland trout brooks.The correspondence between the fish-based typology and the morphology-based German stream typology was rather weak and requires further investigation.     

Study on the suitability of New Zealand coals for hydrogen production

Internationally there is considerable interest in utilizing hydrogen as an energy carrier. The use of hydrogen offers considerable potential benefits such as reducing greenhouse emissions, reducing urban pollution, increased energy security and increased efficiencies from the use of advanced energy conversion technologies.One of the most important questions when considering the development of a hydrogen economy is “where will the hydrogen come from?” Possible answers include electrolysis of water, steam reforming of methane and the gasification of coal. Given the high costs associated with electrolysis of water, and the increase in the cost of methane predicted over time, the gasification of coal is viewed by many as being the cheapest method of hydrogen production in the foreseeable future. These considerations are particularly relevant to New Zealand where gas supplies are dwindling but where there is sufficient coal to last for many centuries at present utilization rates. This, along with the current high international interest in hydrogen energy, has been recognized by the New Zealand Government in the form of a six-year [2002–2008] research project “Hydrogen Energy for the Future of New Zealand”.One important coal property that, in particular, determines the suitability of a particular coal for use in a fluidised bed gasifier is its reactivity towards the gasification reaction. It was found that a high percentage of New Zealand's coal resource is particularly well-suited towards fluidised bed gasification, reacting at anywhere between 0.9 to 1.75 times the rate of Australian brown coals. It was found the New Zealand lignites contained significant levels of organically bound calcium, which was shown to be responsible for not only the high reactivity of the New Zealand lignites, but also a product gas composition with higher than expected hydrogen concentrations. These findings are discussed along with their implications for the gasifier and gas clean-up design.     

The fluid regime of high-temperature metamorphism during granitoid magma genesis

The strong negative correlation between the temperatures and melt H₂O contents of granitoid magmas implies that the crustal melting reactions that produced the magmas were strongly buffered, with T and aH₂O co-varying within a narrow band. This observation can only be explained if the partial melting reactions that created the magmas were either fluid-absent from the outset or evolved toward this condition as melting progressed. Since these melting reactions occur during upper amphibolite- to granulite-facies metamorphism, it is reasonable to conclude that metamorphic events responsible for the generation of granitoid magmas generally occur in the absence of excess pervasive fluid.