Sample records for lahek edvin nugis
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2014-01-01
accuracy by developing dose estimation formulas derived from hematological indices from Chernobyl accident patients measured from 4 – 8 d post...448-54, 2005. [32] A. E. Baranov, A. K. Guskova, N. M. Nadejina, and V. Yu. Nugis,― Chernobyl experience: biological indicators of exposure to
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A new prescription for the mass-loss rates of hydrogen-free WR stars
NASA Astrophysics Data System (ADS)
Tramper, Frank; Sana, Hugues; de Koter, Alex
2017-11-01
We present a new empirical prescription for the mass-loss rates of hydrogen-free Wolf-Rayet stars based on results of detailed spectral analyses of WC and WO stars. Compared to the prescription of Nugis & Lamers (2000), M⊙ is less sensitive to the surface helium abundance, implying a stronger mass loss at the late stages of Wolf-Rayet evolution. The winds of hydrogen-free WN stars have a strong metallicity dependence, while those of WC and WO stars have a very weak metallicity dependence.
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NASA Astrophysics Data System (ADS)
Yoon, Sung-Chul
2017-10-01
Hydrogen-deficient Wolf-Rayet (WR) stars are potential candidates of Type Ib/Ic supernova (SN Ib/Ic) progenitors and their evolution is governed by mass-loss. Stellar evolution models with the most popular prescription for WR mass-loss rates given by Nugis & Lamers have difficulties in explaining the luminosity distribution of WR stars of WC and WO types and the SN Ic progenitor properties. Here, we suggest some improvements in the WR mass-loss rate prescription and discuss its implications for the evolution of WR stars and SN Ib/Ic progenitors. Recent studies on Galactic WR stars clearly indicate that the mass-loss rates of WC stars are systematically higher than those of WNE stars for a given luminosity. The luminosity and initial metallicity dependences of WNE mass-loss rates are also significantly different from those of WC stars. These factors have not been adequately considered together in previous stellar evolution models. We also find that an overall increase of WR mass-loss rates by about 60 per cent compared to the empirical values obtained with a clumping factor of 10 is needed to explain the most faint WC/WO stars. This moderate increase with our new WR mass-loss rate prescription results in SN Ib/Ic progenitor models more consistent with observations than those given by the Nugis & Lamers prescription. In particular, our new models predict that the properties of SN Ib and SN Ic progenitors are distinctively different, rather than they form a continuous sequence.
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This EnviroAtlas dataset contains data on the mean livestock manure application to cultivated crop and hay/pasture lands by 12-digit Hydrologic Unit (HUC) in 2006. Livestock manure inputs to cultivated crop and hay/pasture lands were estimated using county-level estimates of recoverable animal manure from confined feeding operations compiled for 2007. Recoverable manure is defined as manure that is collected, stored, and available for land application from confined feeding operations. County-scale data on livestock populations -- needed to calculate manure inputs -- were only available for the year 2007 from the USDA Census of Agriculture (http://www.agcensus.usda.gov/index.php). We acquired county-level data describing total farm-level inputs (kg N/yr) of recoverable manure to individual counties in 2007 from the International Plant Nutrition Institute (IPNI) Nutrient Geographic Information System (NuGIS; http://www.ipni.net/nugis). These data were converted to per area rates (kg N/ha/yr) of manure N inputs by dividing the total N input by the land area (ha) of combined cultivated crop and hay/pasture (agricultural) lands within a county as determined from county-level summarization of the 2006 NLCD. We distributed county-specific, per area N inputs rates to cultivated crop and hay/pasture lands (30 x 30 m pixels) within the corresponding county. Manure data described here represent an average input to a typical agricultural land type within a county, i.e., the
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ERIC Educational Resources Information Center
Kultti, Anne
2016-01-01
The present paper addresses children's participation through pedagogical structuring in an early childcare programme in Australia. Research shows inequality in participatory opportunities depending on skills in the spoken (majority) language. Against this background, the focus in the present study is on participatory opportunities for toddlers…
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[Untreated syphilis - from Oslo to Tuskegee].
Sandvik, Anniken; Lie, Anne Kveim
2016-12-01
In the period from 1891 - 1910, around 2000 patients with syphilis were admitted to the Department of Dermatology, Oslo University Hospital, Rikshospitalet. The head of the department, Cæsar Boeck (1845 - 1917), believed in allowing the disease to take its natural course and withheld treatment. He made detailed notes of the diagnosis and the clinical course of the disease for all his patients. Boeck's material is unique, and forms the basis for our current knowledge about the prognosis and course of syphilis infections. In 1928, the patients were scrutinised by Boeck's successor in the Department of Dermatology, Edvin Bruusgaard (1869 - 1934), and later by Trygve Gjestland (1911 - 1993). Gjestland's doctoral thesis from 1955 has remained as «The Oslo study of untreated syphilis.» This article presents a medical historical background for the study. Bruusgaard's and Gjestland's research was important for the Tuskegee Study in the USA, and the Oslo study gave implicit support to this research project, which posterity has emphatically condemned as ethically unacceptable.
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WIND STRUCTURE AND LUMINOSITY VARIATIONS IN THE WOLF-RAYET/LUMINOUS BLUE VARIABLE HD 5980
DOE Office of Scientific and Technical Information (OSTI.GOV)
Georgiev, Leonid; Koenigsberger, Gloria; Hillier, D. John
Over the past 40 years, the massive luminous blue variable/Wolf-Rayet system HD 5980 in the Small Magellanic Cloud (SMC) has undergone a long-term S Doradus-type variability cycle and two brief and violent eruptions in 1993 and 1994. In this paper we analyze a collection of UV and optical spectra obtained between 1979 and 2009 and perform CMFGEN model fits to spectra of 1994, 2000, 2002, and 2009. The results are as follows: (1) the long-term S Dor-type variability is associated with changes of the hydrostatic radius; (2) the 1994 eruption involved changes in its bolometric luminosity and wind structure; (3)more » the emission-line strength, the wind velocity, and the continuum luminosity underwent correlated variations in the sense that a decreasing V{sub {infinity}} is associated with increasing emission line and continuum levels; and (4) the spectrum of the third star in the system (Star C) is well fit by a T{sub eff} = 32 K model atmosphere with SMC chemical abundances. For all epochs, the wind of the erupting star is optically thick at the sonic point and is thus driven mainly by the continuum opacity. We speculate that the wind switches between two stable regimes driven by the 'hot' (during the eruption) and the 'cool' (post-eruption) iron opacity bumps as defined by Lamers and Nugis and Graefener and Hamann, and thus the wind may undergo a bi-stability jump of a different nature from that which occurs in OB stars.« less
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Fertilizer Nitrogen Use, Nitrogen Balance Assessment, and Management Education in the U.S
NASA Astrophysics Data System (ADS)
Snyder, C.; Fixen, P.; Bruulsema, T. W.
2011-12-01
Farm fertilizer nitrogen (N) consumption has increased since the 1960s in response to demand for food, feed, fiber, and biofuels by the global human family. In the U.S., fertilizer N consumption increased from about 9.1 million metric tons in 1987 to 11.6 million metric tons in 2007. The International Plant Nutrition Institute has recently developed a nutrient geographic information system (NuGIS) to assess the balance of N and other major plant food nutrients in the U.S. on a county and 8-digit hydrologic unit scale. An evaluation of partial N balances across hydrologic regions was made for the five agricultural census years from 1987 to 2007 and showed positive N balances in all regions. General patterns of slightly lower net positive N balances in the principal cropping regions of the Midwest were observed, and varied but positive partial N balances in the lower Mississippi River Ba¬sin and in many other parts of the country were also reflected. It is recognized that highly positive N balances may pose increased risks for N loss to the environment via leaching to groundwater, runoff/drainage to surface waters and coastal areas, and gaseous emissions of N forms such as nitrous oxide (N2O). Greater farmer and practitioner knowledge is needed to allow more intensive and efficient N management of fertilizer and manure N resources on existing agricultural lands. A 4R Nutrient Stewardship approach has been initiated within the industry and the agricultural community in the U.S., and also globally, to help advance and enhance the concept of ecologically intensive nutrient management. A better understanding of partial N balances and crop N use efficiency improvements are necessary to meet societal food, feed, fiber, and biofuel production requirements, while also protecting and preserving natural areas.
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Burke, Lora E; Shiffman, Saul; Music, Edvin; Styn, Mindi A; Kriska, Andrea; Smailagic, Asim; Siewiorek, Daniel; Ewing, Linda J; Chasens, Eileen; French, Brian; Mancino, Juliet; Mendez, Dara; Strollo, Patrick; Rathbun, Stephen L
2017-03-15
completing EMA surveys was high, with 88.3% (66,978/75,888) completion of random assessments and around 90% (23,411/25,929 and 23,343/26,010) completion of time-contingent assessments, despite the duration of EMA data collection and challenges with implementation. This work informed us of the necessary preliminary steps to plan and prepare a longitudinal study using smartphone technology and the critical elements to ensure participant engagement in the potentially burdensome protocol, which spanned 12 months. While this was a technology-supported and -programmed study, it required close oversight to ensure all elements were functioning correctly, particularly once human participants became involved. ©Lora E Burke, Saul Shiffman, Edvin Music, Mindi A Styn, Andrea Kriska, Asim Smailagic, Daniel Siewiorek, Linda J Ewing, Eileen Chasens, Brian French, Juliet Mancino, Dara Mendez, Patrick Strollo, Stephen L Rathbun. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 15.03.2017.