East coast lows and extratropical transition of tropical cyclones, structures producing severe events and their comparison with mature tropical cyclones

Examination of events occurring over the last 53 years in the Australian Region have revealed in the minds of forecasters a common pattern in the development of severe extratropical cyclones which have affected the sub-tropical and temperate East Coast. To evaluate this theory 20 years of data were systematically examined and showed that this was true. To represent these many cases nine such events which delivered the largest impacts over the 53 years were chosen for study. These extratropical cyclones formed downstream of a tropopause undulation which can be easily identified as a warm region at the 200 hPa-level and the formation zone was in a region of heavy rain embedded in a region of warm air advection at 700 hPa. There were hardly any exceptions to this general rule, and one that occurred is presented and was also one of the most rapidly developing systems. This pattern is then evaluated against tropical cyclone events which move in the Australasian sub tropics and three different scenarios are described and compared with a mature severe tropical cyclone which intensified as it moved into the Australia sub tropics. Hurricane Sandy due to its devastating effect on the US sub-tropics in 2012 is examined as a benchmark case whose impact could affect the Australasian sub tropics in the future as sea levels rise with higher density populations.

Star formation rates in the L 1482 filament of the California molecular cloud

We measured the trigonometric parallax of the H2O maser source associated with the L 1482 molecular filament hosting the most massive young star, LkHα 101, in the California molecular cloud. The measured parallax is 1.879 ± 0.096 mas, corresponding to the distance of 532 ± 28 pc. This parallax is consistent with that of the nearby star cluster LkHα 101, which was recently measured with Gaia DR2. We found that the L 1482 molecular filament and the LkHα 101 cluster are located at the same distance within 3 ± 30 pc. We observed the southern parts of L 1482 molecular clouds including the H2O maser source, which is adjacent to LkHα 101, using the Nobeyama 45 m telescope in the J = 1–0 transitions of both 12CO and 13CO. The peak intensity of the 12CO line revealed the high excitation temperature region (60–70 K) due to heating by UV radiation from LkHα 101. We derived the column density of these molecular clouds assuming local thermodynamic equilibrium (LTE) from the 13CO emission. Using Dendrogam, we searched for small-scale, dense structures (cores) and identified 337 cores in the 13CO data. Gravitationally bound cores with a virial mass to LTE mass ratio ≤1.5 and young stars are concentrated in the high excitation temperature region. The column density in the warm region is five to six times larger than that of the surrounding colder molecular region. This suggests that the warm region has been compressed by a high-pressure wave and successive radiation-driven star formation is in progress in this warm region. In the cold molecular cloud to the north of the warm region, the cores are likely gravitationally unbound, which may be the reason why star formation is not active there.

Evaluation of anthelmintic drugs against egg development of rumen flukes recovered from cattle raised in the humid tropics of Mexico

Paramphistomosis is a parasitic disease endemic in ruminants nearly worldwide. In the present study, an in vitro screening of the main anthelmintics used in Mexico was carried out to determine the mean lethal dose for rumen fluke eggs from cattle in a humid, warm region. Rumen flukes were obtained from cattle slaughtered in the states of Tabasco and Chiapas in Mexico. Eggs were collected using a 37-μm sieve and quantified. Then, an in vitro incubation study was performed: 100 eggs were placed into the wells of polystyrene microtiter plates. Anthelmintic products were tested on the eggs at concentrations ranging from 0.0015 to 3.0 mg/ml for rafoxanide, 0.0025 to 10.20 mg/ml for nitroxinil and 0.0015 to 3 mg/ml for closantel to determine the median lethal dose (LD50) and maximum lethal dose (LD99). A control group (water) was included in each plate. Three different species of rumen flukes (Calicophoron brothriophoron, Calicophoron clavula and Paramphistomum cervi) belonging to five isolates were identified. Nitroxinil had the highest efficacy against rumen fluke eggs, with an LD50 of 0.11 to 65 μg/ml, whereas rafoxanide showed the lowest efficacy with an LD50 ranging from 500 to 1713 μg/ml. Closantel showed high variability in the LD50 among the different analysed isolates (17 to 122 μg/ml). The evaluated flukicidal drugs presented differential efficacy against the development of rumen fluke eggs. The efficacy of the drugs will vary depending on the geographical area of origin of the animals.

Gas-dust chemistry of volatiles in the star and planetary system formation

The focus of this work is on two topics: (i) formation of complex organic molecules (COMs) and (ii) isotope fractionation. Various COMs, which are C, H-containing molecules consisting of 6 atoms and more, have been detected in the central warm region of protostellar cores. Most of this review is about gas-grain chemical models, which have been constructed to evaluate the mechanisms and efficiency of the COM formation. The relevant physical and chemical processes are investigated in laboratory experiments, as reported in other articles in this volume.The isotope fractionation of volatile elements is observed in both the interstellar medium (ISM) and Solar system material. While exothermic exchange reactions enrich molecules with heavier isotopes such as Deuterium, the isotope selective photodissociation can be coupled with ice formation to enrich the ice mantle with rare isotopes. The efficiency of this fractionation depends on the photodesorption yields, which has been studied in laboratory experiments.