The putative nebula of the Wolf-Rayet WR 60 star: a case of mistaken identity and reclassification as a new supernova remnant G310.5+0.8

We present narrow band AAO/UKST Hα images and medium and low resolution optical spectra of a nebula shell putatively associated with the Wolf-Rayet star WR 60. We also present the first identification of this shell in the radio regime at 843 MHz and at 4850 MHz from the Sydney University Molonglo Sky Survey (SUMSS), and from the Parkes-MIT-NRAO (PMN) survey respectively. This radio emission closely follows the optical emission. The optical spectra from the shell exhibits the typical shock excitation signatures sometimes seen in Wolf-Rayet stellar ejecta but also common to supernova remnants. A key finding however, is that the WR 60 star, is not, in fact, anywhere near the geometrical centre of the putative arcuate nebula ejecta as had been previously stated. This was due to an erroneous positional identification for the star in the literature which we now correct. This new identification calls into serious question any association of the nebula with WR 60 as such nebula are usually quite well centred on the WR stars themselves. We now propose that this fact combined with our new optical spectra, deeper Hα imaging and newly identified radio structures actually imply that the WR 60 nebula should be reclassified as an unassociated new supernova remnant which we designate G310.5+0.8.     

Atmospheric mesoscale conditions during the Boothbay meteotsunami: a numerical sensitivity study using a high-resolution mesoscale model

The article aims to test the sensitivity of high-resolution mesoscale atmospheric model to fairly reproduce atmospheric processes that were present during the Boothbay Harbor meteotsunami on 28 October 2008. The simulations were performed by the Weather and Research Forecasting (WRF) model at 1-km horizontal grid spacing by varying initial conditions (ICs) and lateral boundary conditions (LBCs), nesting strategy, simulation lead time and microphysics and convective parameterizations. It seems that the simulations that used higher-resolution IC and LBC were more successful in reproduction of precipitation zone and surface pressure oscillations caused by internal gravity waves observed during the event. The results were very sensitive to the simulation lead time and to the choice of convective parameterization, while the choice of microphysics parameterization and the type of nesting strategy (one-way or two-way) was less important for reproducibility of the event. The success of the WRF model appears limited to very short-range forecasting, most advanced parameterizations, and very high-resolution grid spacing; therefore, the applicability of present atmospheric mesoscale models to future operational meteotsunami warning systems still has a lot of room for improvements.     

Composition and variation of major and trace elements in Croatian bottled waters

Within the framework of the Pan-European project about the geochemistry of bottled mineral waters in Europe launched in 2007 by the European Geological Surveys (EGS) Geochemistry Expert Group fourteen brands of bottled natural waters from Croatia of both mineral and spring types were evaluated for getting more coherent spatial information about the natural variation of element concentration in bottled waters found at the European market. Results of chemical analysis show that not a single one out of fourteen analyzed bottled waters from Croatia exceeds the Croatian water standards sanctioning thereby their suitability for human consumption. Also, statistical tests performed for 41 analytes (including pH and EC) clearly show that the water chemistry is in a high degree of conformity with regional geology, depending on structural, stratigraphic and, above all, lithological diversity of aquifers. Thus Dinaric and Pannonian parts of Croatia differ largely with regard to their water types: Dinaric region is completely lacking mineral water types while, on the other side, in the Pannonian region even the spring waters show stronger mineralization in comparison with their Dinaric counterparts. Typically, all natural waters from Croatia bear the bicarbonate (HCO₃) signature. However, Ca–Mg cation pair combination is characteristic of spring waters while Na–K dominates in the mineral waters.     

A visual basic spreadsheet macro for recession curve analysis

A Visual Basic program for an Excel spreadsheet was written to construct a master recession curve (MRC), using the adapted matching strip method, for recession analysis of ground water level time series. The program uses five different linear/nonlinear regression models to adjust individual recession segments to their proper positions in the MRC. The program can also be used to analyze the recession segments of other time series, such as daily stream discharge or stage. Some examples of field data from Croatia are used to illustrate the usefulness of its application.     

Stark Broadening Data for Stellar Plasma Research

Results of an effort to provide to astrophysicists and physicists a set of Stark broadening parameters that is as complete as possible are presented. Such parameters are needed for stellar opacity calculations, stellar atmosphere modelling, abundance determinations, and diagnostics of various plasmas in astrophysics, physics, and plasma technology. The Stark broadening was treated using a semiclassical perturbation and modified semiempirical approaches.     

Kinematics of Interacting ICMEs and Related Forbush Decrease: Case Study

We study heliospheric propagation and some space weather aspects of three Earth-directed interplanetary coronal mass ejections (ICMEs), successively launched from the active region AR 11158 in the period 13?–?15 February 2011. From the analysis of the ICME kinematics, morphological evolution, and in situ observations, we infer that the three ICMEs interacted on their way to Earth, arriving together at 1 AU as a single interplanetary disturbance. Detailed analysis of the in situ data reveals complex internal structure of the disturbance, where signatures of the three initially independent ICMEs could be recognized. The analysis also reveals compression and heating of the middle ICME, as well as ongoing magnetic reconnection between the leading and the middle ICME. We present evidence showing that the propagation of these two, initially slower ICMEs, was boosted by the fastest, third ICME. Finally, we employ the ground-based cosmic ray observations, to show that this complex disturbance produced a single cosmic ray event, i.e., a simple Forbush decrease (FD). The results presented provide a better understanding of the ICME interactions and reveal effects that should be taken into account in forecasting of the arrival of such compound structures.     

Pleurozium schreberi as bioindicator of mercury pollution in heavily industrialized region

This research is continuation of the investigation of metal accumulation in native and transplanted moss Pleurozium schreberi in the most industrialized and affected region in Poland (Upper Silesia). We tested the hypotheses that in Upper Silesia transplants of P. schreberi may be used in a 90 days bioindication experiment in case native specimens are absent; a 90 days exposure of transplanted P. schreberi was long enough for evaluation of Hg pollution of the environment. An assay was carried out with native mosses at 27 polluted sites and mosses from an uncontaminated control site transplanted to the same 27 polluted sites. P. schreberi collected from the same sites as classified for more and less polluted basing on Pb and Zn concentrations show quite different pattern of pollution with mercury; The accumulation of Hg by the transplants increased much faster in the first 45 days of the experiment (accumulation factor 1.5–6.7; mean 3.4?±?0.5) in comparison with the second period from day 45 to 90 (accumulation factor 1.0–1.6; mean 1.2?±?0.1). The 90 days exposure of transplanted P. schreberi was long enough for evaluation of Hg pollution of the environment. Transplants of P. schreberi may be used in a 90 days bioindication experiment in case native specimens are absent.     

On the Stark Broadening of Lu III Spectral Lines

The electron-impact widths for 27 Lu III spectral lines have been calculated by using the modified semiempirical method. Calculations have been also performed with the published relativistic Hartree-Fock oscillator strengths and additionally, with the approximate formula of Cowley. With the obtained results, the influence of Stark broadening on Lu III lines was investigated in the spectra of A-type stars. The obtained data will be included in the STARK-B database, which is part of the Virtual Atomic and Molecular Data Center – VAMDC.     

Picoplankton composition related to thermohaline circulation: The Albanian boundary zone (southern Adriatic) in late spring

Picoplankton distribution at the boundary zone of the southern Adriatic in May 2009 on a 75 km long shelf-continental slope transect was assessed by combining epifluorescence microscopy, flow cytometry and high-performance liquid chromatography data with hydrographic observations. The picoplankton distribution was greatly influenced by the hydrographic conditions prevailing in the southern Adriatic because of the influence of the Levantine Intermediate Water (LIW) and East Adriatic Current (EAC) forcing. Heterotrophic bacteria numerically dominated the picoplankton community through the entire transect with no significant accumulation. By contrast, picophytoplankton accumulated in the 50–75 m layer, forming a pronounced deep chlorophyll maximum. Synechococcus dominated the photosynthetic picoplankton, whereas picoeukaryotes were the least abundant. The intrusion of warm LIW observed in the layer between 100 and 350 m was followed by Prochlorococcus and Synechococcus peaks (10 × 10³ cells mL⁻¹ and 90 × 10³ cells mL⁻¹, respectively), as well as by the appearance of two Synechococcus ecotypes. Most picoeukaryotes were observed at the offshore stations, where geostrophic current calculation revealed the strongest EAC influence. A strong EAC spread over the central and eastern basin created a barrier for Prochlorococcus, whereas the picoeukaryote maxima coincided with the core of the EAC, suggesting its persistence to hydrological instabilities.     

Effectiveness of conventional management in Mediterranean type artisanal fisheries

Artisanal fisheries throughout the Mediterranean region are managed mostly by applying gear specific regulations. The data about the extent and dynamics by which littoral fish resources respond to commonly proposed changes of such regulations are lacking. Here the results of a 15 year (1995–2009) monitoring programme of littoral fish resources in a pilot region of island Vis aquatorium, central Adriatic Sea, are reported with the scope of investigating whether a more restrictive fishing regime (encompassing an increase in minimum inner layer mesh size of trammel net from 28 to 40 mm and excluding the trammel net from subsistence artisanal fishing) that has progressively been put in place during the study period has been accompanied by expected positive changes of littoral fish resources’ abundance, biomass and structure. Significant increases over time were observed in most of the community indices analyzed (abundance and biomass catch per unit effort, diversity indices) as well as a directional change in abundance and biomass catch composition of littoral fish resources. Positive responses were, however, primarily related with a recovery of Mullus surmuletus stock. Additionally, time-series analysis of ABC curves and their corresponding W index revealed that fish community in the study area was still moderately disturbed. Limited extent of conventional management restorative potential is further exacerbated by social issues – noncompliant behavior mainly among subsistence artisanal fishers and consequent resentment of commercial artisanal fishers. In order to improve further the state of the resources a more comprehensive set of management measures incorporating closed areas and a new approach actively involving fishers in the management process should be adopted.