The U.S. Environmental Protection Agency (EPA) bases its risk assessments, regulatory limits, and nonregulatory guidelines for population exposures to low level ionizing radiation on the linear no-threshold (LNT) hypothesis, which assumes that the risk of cancer due to a low dose exposure is proportional to dose, with no threshold. The use of LNT for radiation protection purposes has been repeatedly endorsed by authoritative scientific advisory bodies, including the National Academy of Sciences' BEIR Committees, whose recommendations form a primary basis of EPA's risk assessment methodology. Although recent radiobiological findings indicate novel damage and repair processes at low doses, LNT is supported by data from both epidemiology and radiobiology. Given the current state of the science, the consensus positions of key scientific and governmental bodies, as well as the conservatism and calculational convenience of the LNT assumption, it is unlikely that EPA will modify this approach in the near future.
Maģistra darbu "Televīzijas loma neapmierinātībā ar politiku: LTV1, LNT, TV3 nedēļas analītisko raidījumu satura, to veidotāju un ekspertu vērtējumu analīze (2008. gada oktobris – 2009. gada marts)" izstrādāja Latvijas Universitātes Komunikācijas studiju nodaļas students Vladimirs Novodvorskis. Darbs veltīts auditorijas negatīvas attieksmes veidošanas problēmas izpētei televīzijas informatīvi analītiskajos raidījumos Panorāma, De facto (LTV1), LNT Top 10 (LNT), Nekā personīga (TV3) pret politiskajiem aktoriem un politiku kopumā. Darba mērķis – šo raidījumu lomas noteikšana negatīvas attieksmes pret politiku veidošanā, kā arī televīzijas ziņu negatīvo un pozitīvo efektu iedarbībā uz auditorijas politisko aktivitāti. Politisko aktoru, masu mediju un auditorijas savstarpējā mijiedarbība tiek iztirzāta politiskās komunikācijas teoriju un mediju teoriju – Maikla Robinsona videonospiestības teorijas (Videomalaise) un Pipas Norisas pastāvīgi atkārtojošos pozitīvo notikumu cikla teorijas (Virtuous circle) ietvaros. Maģistra darba empīriskajā daļā ar kvantitatīvo kontentanalīzi tika noteiktas negatīvo, pozitīvo un neitrālo televīzijas ziņu, stratēģisko televīzijas ziņu (strategic frame) un ziņu pēc būtības (issue frame), ziņu ar izklaides elementu izmantošanu un nopietnu ziņu par sociāli politiskajām tēmām attiecības visos trijos raidījumos. Darbā ir iekļauti daļēji strukturēto interviju ar televīzijas programmu veidotājiem, mediju ekspertiem rezultāti, kā arī socioloģisko datu analīzes, kurus darba autoram sniedza eksperti, rezultāti. Darba galvenais secinājums: visu triju pētāmo televīzijas raidījumu iedarbība uz auditorijas attieksmi pret politiskajiem aktoriem un Latvijas politiskajiem procesiem drīzāk ir negatīva nekā pozitīva un neveicina atgriezeniskās selektīvās saites darbību starp auditoriju un politiskajiem aktoriem. Atslēgvārdi: videonospiestība (videomalaise), politiskā komunikācija, televīzija, Nekā personīga, LNT Top 10, Panorāma, De facto. ; . The master work The role of television in discontentment toward politics: the analysis of content, creators and expert evaluation of weekly analytical programs, broadcast on LTV-1, LNT, TV-3 (October 2008-March 2009) developed by student in the Department of Communication Studies at the Latvia University Vladimirs Novodvorskis. The work is devoted to the research of negative impact of analytical informative television programs such as "Panorāma", "De Facto" (LTV-1), "LNT Top 10" (LNT), "Nekā personīga" (TV-3) on audience against political factors and politics. The aim of the research is to define of the role of these programs in negative attitudes toward policy-making, as well as the television report negative and positive effects on the audience of political engagement. The interdependence of political factors, mass media and the audience is examined within the framework of theoretical communication and media theory: Michael Robinson video malaise theory and Pippa Norris virtuous circle theory. In empirical part of the master's work the negative, positive and neutral television reports, strategic television report (strategic frame), and a message of substance (issue frame), a message with entertainment features and a serious message about the socio-political themes in all three programs were defined using the quantitative content analysis. Work includes the results of semi structured interviews with the TV program makers, media experts and sociological analysis of data presented to the author of the work by experts. The main conclusion of the work: the effects of all three investigational television programs on the attitude of audience towards political factors and political processes in Latvia are negative rather than positive and not conducive to the selective operation of the link between the audience and political actors. Keywords: video malaise, political communication, television, "Nekā personīga", "LNT Top 10", "Panorāma, De Facto".
Book review:Kathy Ehrensperger – Nathan MacDonald – Luzia Sutter Rehmann (eds.), DecisiveMeals. Table Politics in Biblical Literature (Library of New Testament Studies 449; London – New York: T&T Clark, 2012). Pp. 182 + XVII. $120.00 (Hardback).ISBN 9780567526014.
10 p.-6 fig. ; Background: Different bacteria have been reported so far that link selenite resistance to the production of metallic selenium nanoparticles (SeNPs). Although SeNPs have many biotechnological applications in diverse areas, the molecular mechanisms involved in their microbial genesis are not fully understood. The Azoarcus genus is a physiologically versatile group of beta-proteobacteria of great environmental relevance. Azoarcus sp. CIB is a facultative anaerobe that combines the ability to degrade under aerobic and/or anaerobic conditions a wide range of aromatic compounds, including some toxic hydrocarbons such as toluene and m-xylene, with an endophytic life style in the root of rice. We unravel here an additional physiological feature of the strain CIB that is related to its resistance to selenium oxyanions and the formation of SeNPs. ; Results: This work is the first report of a member of the Azoarcus genus that is able to anaerobically grow in the presence of selenite. Electron microscopy preparations and X-ray spectroscopy analyses demonstrate the reduction of selenite to spherical electron-dense SeNPs whose average size was 123 ± 35 nm of diameter. Our data suggest that the main molecular mechanism of selenite resistance resides on an energy-dependent selenite exporter. Azoarcus cells trigger the synthesis of SeNPs when they reach the stationary-phase of growth, and either the exhaustion of electron donor or acceptor, both of which lead to starvation conditions, produce the reduction of selenite to red elemental selenium. Azoarcus becomes a promising biocatalyst, either as whole cells or cellular extracts, for the anaerobic and/or aerobic green synthesis of SeNPs. ; Conclusions: Azoarcus turns out to be a new eco-friendly system to reduce selenite and produce spherical SeNPs.Moreover, this is the first report of a rice endophyte able to produce SeNPs. Since Azoarcus is also able to degrade both aerobically and anaerobically toxic aromatic compounds of great environmental concern, it becomes a suitable candidate for a more sustainable agricultural practice and for bioremediation strategies. ; This work was supported by Ministry of Economy and Competitiveness of Spain Grants BIO2012-39501 and MAT2014-59222R, Fundación RamónAreces XVII CN, and by European Union FP7 Grant 311815 (Synpol Project). H.Fernández-Llamosas was the recipient of a Research Personnel Formation (FPI) fellowship from the Ministry of Economy and Competitiveness of Spain. ; Peer reviewed
The US Environmental Protection Agency (USEPA) is the primary federal agency responsible for promulgating regulations and policies to protect people and the environment from ionizing radiation. Currently, the USEPA uses the linear no-threshold (LNT) model to estimate cancer risks and determine cleanup levels in radiologically contaminated environments. The LNT model implies that there is no safe dose of ionizing radiation; however, adverse effects from low dose, low-dose rate (LDDR) exposures are not detectable. This article (1) provides the scientific basis for discontinuing use of the LNT model in LDDR radiation environments, (2) shows that there is no scientific consensus for using the LNT model, (3) identifies USEPA reliance on outdated scientific information, and (4) identifies regulatory reliance on incomplete evaluations of recent data contradicting the LNT. It is the time to reconsider the use of the LNT model in LDDR radiation environments. Incorporating the latest science into the regulatory process for risk assessment will (1) ensure science remains the foundation for decision making, (2) reduce unnecessary burdens of costly cleanups, (3) educate the public on the real effects of LDDR radiation exposures, and (4) harmonize government policies with the rest of the radiation scientific community.
The Linear Non-Threshold (LNT) process is used by virtually all governmental agencies to compute incidence of cancer as a consequence of exposure to a carcinogen. This comment applies the concept of Best Available Science (BAS) Metrics for Evaluation of Scientific Claims (MESC) derived from BAS to issues related to reliability of LNT hypothesis. This paper identifies the level of maturity of the LNT hypothesis and the associated uncertainties.
