MOL-D: A Collisional Database and Web Service within the Virtual Atomic and Molecular Data Center     

V. Vujčič  D. Jevremović  A. A. Mihajlov  Lj. M. Ignjatović  V. A. Srećković  M. S. Dimitrijević  M. Malović 《Journal of Astrophysics and Astronomy》2015,36(4)

MOL-D database is a collection of cross-sections and rate coefficients for specific collisional processes and a web service within the Serbian Virtual Observatory (SerVO) and the Virtual Atomic and Molecular Data Center (VAMDC). This database contains photo-dissociation cross-sections for the individual ro-vibrational states of the diatomic molecular ions and rate coefficients for the atom-Rydberg atom chemi-ionization and inverse electron–ion–atom chemi-recombination processes. At the moment it contains data for photodissociation cross-sections of hydrogen H\(_{2}^{+}\) and helium He\(_{2}^{+}\) molecular ions and the corresponding averaged thermal photodissociation cross-sections. The ro-vibrational energy states and the corresponding dipole matrix elements are provided as well. Hydrogen and helium molecular ion data are important for calculation of solar and stellar atmosphere models and for radiative transport, as well as for kinetics of other astrophysical and laboratory plasma (i.e. early Universe).  相似文献   

Inverse Bremsstrahlung in Astrophysical Plasmas: The Absorption Coefficients and Gaunt Factors     

A. A. Mihajlov  V. A. Srećković  N. M. Sakan 《Journal of Astrophysics and Astronomy》2015,36(4)

The electron–ion inverse Bremsstrahlung is considered here as a factor of the influence on the opacity of the different stellar atmospheres and other astrophysical plasmas. It is shown that this process can be successfully described in the frames of cut-off Coulomb potential model within the regions of the electron densities and temperatures. The relevant quantum mechanical method of the calculation of the corresponding spectral coefficient processes is described and discussed. The results obtained for the plasmas with the electron densities from 10¹⁴ cm ^?3 to 2?10¹⁹ cm ^?3 and temperatures from 5?10³ K to 3?10⁴ K in the wavelength region 100 nm<λ<3000 nm are presented. Also, these results can be of interest for different laboratory plasmas.  相似文献   

Cellular energy allocation in mussels (Mytilus galloprovincialis) from the stratified estuary as a physiological biomarker     

Erk M  Ivanković D  Strižak Ž 《Marine pollution bulletin》2011,62(5):1124-1129

This study demonstrates the usefulness of cellular energy allocation (CEA) evaluations as a physiological biomarker to infer the occurrence of natural stress in native populations of mussels inhabiting the stratified estuary (Krka River estuary, Croatia). Sampling sites were selected based on their differences in the salinity and temperature. The CEA value was calculated as a ratio between available energy (E_a) and energy consumption (E_c). Generally, higher values of E_a were recorded in June than in November, which were especially evident in the storage components (carbohydrates and lipids), while the constitutive component (proteins) remained relatively constant. The highest E_c was recorded in mussels at estuarine site compared to coastal site, which may be caused by the energetically costly maintenance of osmotic balance. Decrease in CEA recorded in estuarine mussels may ultimately result in a lower amount of energy available for growth, reproduction, or defence against other stresses (e.g. pollution).  相似文献   

Distal “impact” layers and global acidification of ocean water at the Cretaceous-Paleogene boundary (KPB)     

P. I. Premović 《Geochemistry International》2011,49(1):55-65

The KPB sections at Højerup in Denmark, Agost and Caravaca in Spain and El Kef in Tunisia and (elsewhere in the world) consists of a very thin reddish biogenic calcite-poor smectite-rich “impact” layer overlain by a thicker smectite-rich marl. The massive amount of impact-generated atmospheric CO₂ at KPB would have accumulated globally in the ocean surface, leading to acidification and CaCO₃ undersaturation. These chemical changes would have induced a low biocalcification of calcareous plankton and a high dissolution of their shells. The biocalcification/dissolution crises may have played a significant role for the low abundance of biogenic calcite in the “impact” layer of the marine boundary clays at Højerup, Agost, Caravaca and El Kef (and elsewhere in the world). Experimental data and observations indicate that the deposition of the “impact” layer probably lasted only a few decades at most.  相似文献   

An energy budget for the subtidal bivalve Modiolus barbatus (Mollusca) at different temperatures     

Ezgeta-Balić D  Rinaldi A  Peharda M  Prusina I  Montalto V  Niceta N  Sarà G 《Marine environmental research》2011,71(1):79-85

Clearance rates, respiration rates and food absorption efficiencies of the commercially interesting subtidal bivalve Modiolus barbatus were measured at different temperatures under laboratory conditions and scope for growth calculated. Clearance rates were highest at temperatures from 20 °C to 28 °C, whereas respiration rate was maximal at 9 °C and minimal at 26 °C. Highest mean values of absorbed energy occurred at 20 °C and 26 °C. Scope for growth trend had negative values at 9 °C, 15 °C and 28 °C and positive values at temperatures 20 °C and 26 °C. The profitable thermal window for M. barbatus to have energy sufficient for growth and reproduction corresponded to <5 months per year. Seawater temperature increases will potentially impact the eco-physiological responses of subtidal M. barbatus causing life history traits to change with important repercussions for subtidal biodiversity in the Mediterranean.  相似文献   

Wave height statistics for seakeeping assessment of ships in the Adriatic Sea     

Joško Parunov  Maro Ćorak  Marina Pensa 《Ocean Engineering》2011,38(11-12):1323-1330

The paper presents methodology and results of the development of sea states statistics for the Adriatic Sea. Such statistics is still lacking despite a need of the shipping industry. The presented study is based on the Atlas of Climatology containing statistics of sea states observations in the Adriatic Sea made by merchant ships during the period of 15 years. The results, presented in the Atlas in the form of “wave roses”, are digitalized and empirical frequencies of sea state occurrences are obtained. The 3-parametric Weibull distribution is then fitted through empirical data points enabling the “smoothening” of the histogram. The resulting histogram is compared with other studies for the long-term prediction of the sea states in the Adriatic Sea. The paper concludes with the discussion on the accuracy and applicability of the results.  相似文献   

Loggerhead sea turtles (Caretta caretta) as bioturbators in neritic habitats: an insight through the analysis of benthic molluscs in the diet     

Bojan Lazar  Romana Gračan  Jelena Katić  Dušan Zavodnik  Andrej Jaklin  Nikola Tvrtković 《Marine Ecology》2011,32(1):65-74

Molluscs are a diverse and ubiquitous group of organisms which contribute to the formation of biogenic sediments and are one of the major prey taxa for the neritic‐stage loggerhead sea turtles (Caretta caretta) worldwide. Here we investigated to what degree molluscs contribute to the diet of individual turtles, and what role the feeding strategy of loggerheads might play in bioturbation, one of the key processes in nutrient transport in marine ecosystems. We performed a detailed analysis of benthic molluscs from the digestive tracts of 62 loggerhead sea turtles (curved carapace length: 25.0–85.4 cm) found in the Northern Adriatic Sea. From 50 of the turtles that contained benthic molluscs, we identified 87 species representing 40 families and three classes (Gastropoda, Bivalvia and Scaphopoda), including 72 new dietary records for loggerhead turtle. Most of the identified molluscs were small‐sized species (shell length ≤ 3 cm) and were often found in a subfossil condition. Their intake may be considered a byproduct of infaunal mining, while larger molluscs were mainly found crushed into smaller fragments. Through such foraging behaviour loggerheads actively rework sediments, increase the surface area of shells and the rate of shells disintegration, acting as bioturbators in this system. We conservatively estimate that loggerheads in the neritic zone of the Adriatic Sea bioturbate about 33 tonnes of mollusc shells per year, and hypothesize about the possible effects of bioturbation reduction on environmental changes in the Northern Adriatic ecosystem.  相似文献   

Hydrogeology Of Slanac Spring,Croatia     

O. Bonacci  F. Fritz  V. Denić < 《Hydrogeology Journal》1995,3(3):31-40

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Heavy metals in sediments—problems concerning determination of the anthropogenic influence. Study in the Krka River estuary,eastern Adriatic coast,Yugoslavia     

Esad Prohić  Mladen Juračić 《Environmental Geology》1989,13(2):145-151

Factors that govern heavy metal concentration in sediments were examined by a combined analytical, geochemical, and geological approach. The constrains encountered in the determination of the anthropogenic influence are exposed. The region examined was the Krka River estuary located in the typical karst region of the eastern Adriatic, Yugoslavia.Sedimentological research revealed that: the Krka River (main water supplier) is almost free of suspended terrigenous material; the main supplier of suspended terrigenous matter of flysch origin is a small torrent-type Gudua Creek, and that this fine grained terrigenous material is sedimented mostly in the central enlarged part of the estuary, the Prokljan Lake.Three different groups of heavy metals were identified in recent sediments. Increased concentrations of nickel and zinc were found in estuarine sediments due to strongnatural enrichment in source rocks. Manganese and chromium were found to benaturally enriched and depleted in surface layer respectively, due to the different postdepositional geochemical behavior. Lead and copper concentrations were found to be increased in surface sediments in the central part of the estuary, apparently from anthropogenic source.  相似文献   

Dependence of the simulated seeding effects of Cb cloud on the types of the AgI agents     

M. Ćurić  D. Janc 《Meteorology and Atmospheric Physics》1993,52(1-2):91-100

Summary A one-dimensional kinematic model is used to investigate the effects of silver iodide seeding in the region of a Cb cloud between isotherms of –8°C and –12°C. The agent interaction with cloud atmosphere is simulated by an improved microphysical model version which includes phoretic processes. The behaviour of the different agent types is investigated using the maximum values of agent mixing ratios and corresponding agent particle masses and radii.It is shown that the agent residence time in the seeding zone significantly depends on vertical velocity. The residence time is comparable to that previously reported. On the other side, the final graupel production decreases slightly when vertical velocity increases, while the corresponding graupel production is quite different for agents used. The main agent nucleation mechanisms are the Brownian coagulation of cloud droplets, inertial impact of cloud droplets and deposition nucleation.With 9 Figures  相似文献