341 research outputs found
MOA-2011-BLG-262Lb : a sub-earth-mass moon orbiting a gas giant primary or a high velocity planetary system in the galactic bulge
No full textD.P.B. was supported by grants NASA-NNX12AF54G, JPL-RSA 1453175 and NSF AST-1211875. This MOA project is supported by the grants JSPS18253002 and JSPS20340052. T.S. acknowledges the financial support from the JSPS, JSPS23340044, JSPS24253004. This work was partially supported by a NASA Keck PI Data Award, administered by the NASA Exoplanet Science Institute. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. B.S.G. and A.G. were supported by NSF grant AST 110347. B.S.G., A.G., R.P.G. were supported by NASA grant NNX12AB99G. S.D. was partly supported through a Ralph E. and Doris M. Hansmann Membership at the IAS and by NSF grant AST-0807444. Work by J.C.Y. was performed in part under contract with the California Institute of Technology (Caltech) funded by NASA through the Sagan Fellowship Program. The OGLE project has received funding from the European Research Council under the European Community's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement No. 246678 to A.U. D.H. was supported by Czech Science Foundation grant GACR P209/10/1318. D.M.B., M.D., K.H., C.S., R.A.S., M.H. and Y.T. are supported by NPRP grant NPRP-09-476-1-78 from the Qatar National Research Fund (a member of the Qatar Foundation).We present the first microlensing candidate for a free-floating exoplanet-exomoon system, MOA-2011-BLG-262, with a primary lens mass of M host ~ 4 Jupiter masses hosting a sub-Earth mass moon. The argument for an exomoon hinges on the system being relatively close to the Sun. The data constrain the product MLπrel where ML is the lens system mass and πrel is the lens-source relative parallax. If the lens system is nearby (large πrel), then ML is small (a few Jupiter masses) and the companion is a sub-Earth-mass exomoon. The best-fit solution has a large lens-source relative proper motion, μrel = 19.6 ± 1.6 mas yr–1, which would rule out a distant lens system unless the source star has an unusually high proper motion. However, data from the OGLE collaboration nearly rule out a high source proper motion, so the exoplanet+exomoon model is the favored interpretation for the best fit model. However, there is an alternate solution that has a lower proper motion and fits the data almost as well. This solution is compatible with a distant (so stellar) host. A Bayesian analysis does not favor the exoplanet+exomoon interpretation, so Occam's razor favors a lens system in the bulge with host and companion masses of M host = 0.12 +0.19-0.06 MΘ and mcomp = 18+28-10M⊕, at a projected separation of a⊥ = 0.84+0.25−0.14 AU. The existence of this degeneracy is an unlucky accident, so current microlensing experiments are in principle sensitive to exomoons. In some circumstances, it will be possible to definitively establish the mass of such lens systems through the microlensing parallax effect. Future experiments will be sensitive to less extreme exomoons.Peer reviewe
Modelling the Dissolved Inorganic Carbon System in the Baltic Sea
No full textOceans are capable of storing part of the emitted anthropogenic carbon dioxide (CO2) due to the formation of carbonic acid and subsequent dissociation. CO2 is also assimilated by biota and the inorganic carbon system is thus coupled to biogeochemical processes. Naturally, it is a substantial improvement of model realism if the inorganic carbon system is fully coupled to biogeochemistry in numerical models. The focus of this thesis has been to improve the accuracy of pH and the partial pressure of CO2 (pCO2) computations for a marine environment like the Baltic Sea, but the knowledge we have gained is generally applicable. A model system has been developed to consider several environmental threats simultaneously (eutrophication, acidification, and climate change) and the model skill has been certified by using objective skill metrics.
To improve the coupling between biogeochemical processes and the dissolved inorganic carbon system, generation and depletion of total alkalinity (AT) due to several biogeochemical reactions was added to the model. In situ generation of AT was found to be important, specifically in regions with permanent or periodic anoxia, as the major AT changes were coupled to oxidation–reduction (redox) reactions. Without adding AT from these processes, the correct pH could not be calculated in anoxic waters and the mean volume AT content was found to be too low.
The improvements were put to use when several environmental threats were evaluated simultaneously in a study of possible future changes in the Baltic Sea pH and oxygen balances. A coupled model for the catchment and sea was set up and forced by meteorological and hydrological datasets and scenarios. The results showed that increased nutrient loads will not inhibit future Baltic Sea acidification, but the seasonal pH cycle will be amplified by increased biological production and mineralization. The study indicated future acidification of the whole Baltic Sea and that the main factor controlling the direction and magnitude of the change was the atmospheric CO2 concentration. Through a previous investigation of the sensitivity of Baltic Sea surface water pH it was found that increased atmospheric CO2 can affect pH also through changing the river chemistry, especially with regard to AT. The latter could severely impact water in the northern Baltic region.
To improve modelled seasonal pCO2 variations dissolved organic matter was added to a numerical model. The modelled phytoplankton were allowed to utilize the dissolved organic nutrients and the biological drawdown of CO2 in the Eastern Gotland basin was much improved by this. When phytoplankton used the organic nutrients the CO2 assimilation was higher during the summer months and the partial pressure of CO2 decreased by ~200 µatm in the Eastern Gotland Basin as a result. In the Bothnian Bay, both the duration and magnitude of CO2 assimilation was doubled when phytoplankton utilized dissolved organic nutrients
Stellar variability in the MOA database
No full textResearch undertaken for this thesis aimed to detect and identify stellar variability in the database of the Japan/New Zealand MOA collaboration. The database of stars collected by the MOA project provided an extensive source of raw data for analysis. Detection of stellar variability was performed by several C++ programs created by the author, which incorporated the Welch and Stetson variability index, the Schwarzenburg-Czerny period folding program, a microlensing modelling program and a transit, detection program. The search for stellar variability produced 83 Cepheid variables, 265 long period variables, 59 eclipsing binaries and 6 potential microlensing events. Sixteen potentially interesting variations that could correspond to planetary transits were also detected. The folded lightcurve of one of the potential transits was categorised as a 'very interesting transit' and 15 were categorised as 'interesting transits'. The search for planetary transits ultimately proved unsuccessful, however, a detailed statistical study of the MOA data revealed several alterations concerning observational procedures which could be made to optimise the MOA data for any future search for planetary transits
Virtual 3D PDF of coastal moa (Euryapteryx curtus) skull
No full textThis zip file contains a virtual 3D skull (based on surface mesh of finite element model) of the coastal moa (Euryapteryx curtus) specimen NMNZ S30212 analysed in the paper. This file is in PDF format (.pdf) and can be viewed for free using the most recent version of adobe reader. Additional formats are available upon request to the author
Virtual 3D PDF South Island giant moa (Dinornis robustus) skull
No full textThis zip file contains a virtual 3D skull (based on surface mesh of finite element model) of the South Island giant moa (Dinornis robustus) specimen NMNZ S28225 analysed in the paper. This file is in PDF format (.pdf) and can be viewed for free using the most recent version of adobe reader. Additional formats are available upon request to the author
Virtual 3D PDF of crested moa (Pachyornis australis) skull
No full textThis zip file contains a virtual 3D skull (based on surface mesh of finite element model) of the crested moa (Pachyornis australis) specimen NMNZ S27896 analysed in the paper. This file is in PDF format (.pdf) and can be viewed for free using the most recent version of adobe reader. Additional formats are available upon request to the author
Virtual 3D PDF of little bush moa (Anomalopteryx didiformis) skull
No full textThis zip file contains a virtual 3D skull (based on surface mesh of finite element model) of the little bush moa (Anomalopteryx didiformis) specimen NMNZ S35274 analysed in the paper. This file is in PDF format (.pdf) and can be viewed for free using the most recent version of adobe reader. Additional formats are available upon request to the author
Kustzonsmodellen inom vattenförvaltningen : Vidareutveckling av användningsområden
No full textDenna rapport presenterar förslag på hur Kustzonsmodellen kan användas för att effektivisera förvaltningen av Sveriges kustvatten. Rapporten riktar sig framförallt till handläggare på myndigheter och forskare som arbetar med vattenförvaltning. Resultatet kan användas för vidare metodutveckling, men också för exempelvis utplacering av representativa övervakningsstationer eller som grund för gruppering av vattenförekomster. Rapporten har tagits fram av SMHI, på uppdrag från Havs- och vattenmyndigheten. Bakgrund I Sverige finns en modell uppsatt för hela kustlinjen för beräkning av vattenkvalitet. Uppdragets syfte har varit att utforska nya användningsområden för denna kustzonsmodell inom vattenförvaltningen. Då uppdragets syfte främst har varit att testa nya sätt att använda kustzonsmodellen inom förvaltningen, ges få rekommendationer. Istället ger uppdraget ett underlag som kan användas vidare. Förvaltningen av Sveriges kustvatten ställer krav på god kunskap om miljötillståndet. Information kan samlas in genom provtagningar av kustvattnet, men dessa kan aldrig bli heltäckande. Ett alternativ är att utifrån kunskap om mänsklig påverkan och kunskap om vattnens karakteristiska modellera tillståndet. Resultat från modellen kan sedan verifieras med provtagningar. Denna rapport presenterar förslag på hur Kustzonsmodellen kan användas för att effektivisera förvaltningen av Sveriges kustvatten
Modelling the Dissolved Inorganic Carbon System in the Baltic Sea
No full textOceans are capable of storing part of the emitted anthropogenic carbon dioxide (CO2) due to the formation of carbonic acid and subsequent dissociation. CO2 is also assimilated by biota and the inorganic carbon system is thus coupled to biogeochemical processes. Naturally, it is a substantial improvement of model realism if the inorganic carbon system is fully coupled to biogeochemistry in numerical models. The focus of this thesis has been to improve the accuracy of pH and the partial pressure of CO2 (pCO2) computations for a marine environment like the Baltic Sea, but the knowledge we have gained is generally applicable. A model system has been developed to consider several environmental threats simultaneously (eutrophication, acidification, and climate change) and the model skill has been certified by using objective skill metrics. To improve the coupling between biogeochemical processes and the dissolved inorganic carbon system, generation and depletion of total alkalinity (AT) due to several biogeochemical reactions was added to the model. In situ generation of AT was found to be important, specifically in regions with permanent or periodic anoxia, as the major AT changes were coupled to oxidation–reduction (redox) reactions. Without adding AT from these processes, the correct pH could not be calculated in anoxic waters and the mean volume AT content was found to be too low. The improvements were put to use when several environmental threats were evaluated simultaneously in a study of possible future changes in the Baltic Sea pH and oxygen balances. A coupled model for the catchment and sea was set up and forced by meteorological and hydrological datasets and scenarios. The results showed that increased nutrient loads will not inhibit future Baltic Sea acidification, but the seasonal pH cycle will be amplified by increased biological production and mineralization. The study indicated future acidification of the whole Baltic Sea and that the main factor controlling the direction and magnitude of the change was the atmospheric CO2 concentration. Through a previous investigation of the sensitivity of Baltic Sea surface water pH it was found that increased atmospheric CO2 can affect pH also through changing the river chemistry, especially with regard to AT. The latter could severely impact water in the northern Baltic region. To improve modelled seasonal pCO2 variations dissolved organic matter was added to a numerical model. The modelled phytoplankton were allowed to utilize the dissolved organic nutrients and the biological drawdown of CO2 in the Eastern Gotland basin was much improved by this. When phytoplankton used the organic nutrients the CO2 assimilation was higher during the summer months and the partial pressure of CO2 decreased by ~200 µatm in the Eastern Gotland Basin as a result. In the Bothnian Bay, both the duration and magnitude of CO2 assimilation was doubled when phytoplankton utilized dissolved organic nutrients
MOA - An Evaluation Model for Implementation and Use of IT in Organizations
No full textMOA is an evaluation model for implementation of IT in organisations, developed by the author. The model has been used for several evaluation studies, and has been slightly modified in order to be useful for different fields of informatics. The MOA-E model has been used for case studies within the field of Computer-Supported Co-operative Work and implementation of e-Government. The MOA-L model has been used for case studies within the field of e-Learning at work for web-based internally developed courses. The MOA model has also been used as a scenario model (MOA-S). The basic model primarily focuses on the three different aspects work processes (from a management perspective), work situations (from the perspectives of the employees) and quality of services (or product) produced (from the perspective of the customers/clients or patients). The model has mainly been used in a process-oriented way, studying implementation and use at different stages of the development process. The aim of the paper is to describe the model and the main experiences from the use of the model. Some experiences from the use of the model are usefulness for many different fields of informatics and flexibility. The model combines simplicity and complexity in a flexible way. The focus on different perspectives of the model facilitates the design of technology, organisation (and education) leading to a “win-win”-scenario for the different interest groups, and also the evaluation of consequences for different interest groups.</p
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