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Do American presidential campaigns polarize or unify partisan perceptions? I propose that they do both, where the balance of these countervailing forces varies by context. Campaign messages enable partisan differences, especially in battleground states, but campaigns also promote social contexts that foster accuracy motives and reduce the effects of partisan biases nationwide. After documenting panel data evidence of campaign trends toward unity, further tests compare the national effects of campaign engagement with the local effects of campaign intensity using daily survey data on national economic evaluations. In support of the countervailing forces framework, national engagement in presidential campaigns generally increased levels of cross-partisan agreement by campaign’s end, but local campaign intensity enhanced partisan differences in rate of responsiveness to the campaign. Although targeted campaigns reduced unifying effects in many states, presidential campaigns typically have a net unifying effect on American economic perceptions, thereby strengthening economic voting.

A well-developed body of research offers ways to measure the partisan advantages that result from legislative districting. Although useful to researchers and legal practitioners, those studies also suffer from theoretical, empirical, and legal limitations. In this essay, we review measures of partisan bias and methods for both simulating election results under existing maps and simulating hypothetical maps. We start by describing the concept of partisan bias and how it has been measured. Then, we turn to new simulation methods that generate hypothetical election results or districts to judge the fairness of a map. While both kinds of evaluation are useful, we point to some unresolved questions and areas for future research.

This paper is the result of a nationwide study of polling place dynamics in the 2016 presidential election. Research teams, recruited from local colleges and universities and located in twenty-eight election jurisdictions across the United States, observed and timed voters as they entered the queue at their respective polling places and then voted. We report results about four specific polling place operations and practices: the length of the check-in line, the number of voters leaving the check-in line once they have joined it, the time for a voter to check in to vote (i.e., verify voter’s identification and obtain a ballot), and the time to complete a ballot. Long lines, waiting times, and times to vote are closely related to time of day (mornings are busiest for polling places). We found the recent adoption of photographic voter identification (ID) requirements to have a disparate effect on the time to check in among white and nonwhite polling places. In majority-white polling places, scanning a voter’s driver’s license speeds up the check-in process. In majority nonwhite polling locations, the effect of strict voter ID requirements increases time to check in, albeit modestly.

Good education requires student experiences that deliver lessons about practice as well as theory and that encourage students to work for the public good—especially in the operation of democratic institutions (Dewey 1923; Dewy 1938). We report on an evaluation of the pedagogical value of a research project involving 23 colleges and universities across the country. Faculty trained and supervised students who observed polling places in the 2016 General Election. Our findings indicate that this was a valuable learning experience in both the short and long terms. Students found their experiences to be valuable and reported learning generally and specifically related to course material. Postelection, they also felt more knowledgeable about election science topics, voting behavior, and research methods. Students reported interest in participating in similar research in the future, would recommend other students to do so, and expressed interest in more learning and research about the topics central to their experience. Our results suggest that participants appreciated the importance of elections and their study. Collectively, the participating students are engaged and efficacious—essential qualities of citizens in a democracy.

Studies of macropartisanship exclusively focus on presidential performance’s role in driving partisan updating. Performance may determine which party benefits from updating, but I propose that the ...

Political trust is a perennially important concern and the events of the last few years have, in many ways, heightened this importance. The relevant scholarship has done much to meet this challenge but continues to struggle with definitional unclarities and an inability to provide accounts that consistently operate as expected. The current research seeks to test the potential of a classic model of trust from the organizational sciences that makes specific arguments regarding the psychological nature and mechanisms of the construct in helping to address these concerns. Using data from a national convenience sample, we provide preliminary evidence which suggests that measures and models addressing this theoretical account of psychological trust form unidimensional and reliable measures that may more precisely explain the process of political trust and outperform current measures in predicting relevant correlates. We conclude by discussing the implications and limitations of our work and, in so doing, lay a foundation for a new research agenda for political trust.

The observed rate of Americans voting for a different party across successive presidential elections has never been lower. This trend is largely explained by the clarity of party differences reducing indecision and ambivalence and increasing reliability in presidential voting. American National Election Studies (ANES) Times Series study data show that recent independent, less engaged voters perceive candidate differences as clearly as partisan, engaged voters of past elections and with declining rates of ambivalence, being undecided, and floating. Analysis of ANES inter-election panel studies shows the decline in switching is present among nonvoters too, as pure independents are as reliable in their party support as strong partisans of prior eras. These findings show parties benefit from the behavioral response of all Americans to polarization. By providing an ideological anchor to candidate evaluations, polarization produces a reliable base of party support that is less responsive to short-term forces.

Objectives To determine the prevalence of oral mucosal lesions in a sample of older Danish people and to investigate their associations with age, gender, systemic diseases, medications, xerostomia and salivary secretion. Methods A total of 668 community-dwelling individuals aged 65–95 years underwent a clinical examination, measurements of unstimulated and stimulated whole and labial salivary flow rates and an interview regarding xerostomia, general health, medication, tobacco and alcohol habits. Results Seventy-five per cent of all participants and 70% of the non-medicated ones had one or more oral mucosal lesions. The most prevalent lesions were lingual varicosities (28.3%), denture stomatitis (12.7%), candidiasis (11.8%), fissured tongue (9.1%) and frictional keratosis (8.4%). Lesions were generally associated with smoking and xerostomia. Varicosities were more common in participants with systemic diseases and medication intake, particularly with cardiovascular diseases and agents. Fissured tongue and atrophic tongue were associated with female gender, xerostomia and low unstimulated whole and labial salivary secretion. Oral candidiasis was associated with older age; being male; current smoker; having >3 diseases, intake of medications and low salivary flow rates; and identified in relation to denture stomatitis, fissured tongue and atrophic tongue and median rhomboid glossitis. Conclusions Oral mucosal lesions are prevalent in older Danish people and generally associated with changes in both local and systemic factors. Tongue lesions in particular appeared as indicators that may identify patients with specific need of oral intervention.

Among the novel events and frequently discussed features of the 2012 presidential election, none is more obvious or, perhaps, more relevant to the state of the U.S. democracy than the ubiquity of money. Money has long played a role in presidential campaigns, but scholars frequently disagree over its effects. Political observers also hold a range of perspectives on the normative value of campaign expenditures between believing that money is a form of expression, and thus should be welcomed and protected in campaigns, to believing that money corrupts campaigns and representatives by favoring the wealthy at the expense of those with less. Related debates about money's effects on campaigns and political representation in the United States continued throughout 2012 following major reconfigurations in its campaign finance laws. These changes made it possible for citizens to spend unlimited sums of money on campaigns through independent expenditure-only committees, better known as Super Political Action Committees (Super PACs), and made the 2012 presidential campaign the first to experience unlimited outside spending via Super PACs. The emergence of Super PACs within the 2012 presidential campaign thus prompts a reexploration of our understanding of the key factors of campaign dynamics and fundamental concerns about the role of money in campaigns. We analyze the role of Super PACs in the campaign for the 2012 Republican Presidential nomination. Super PACs contributed throughout the campaign, but their presence was particularly pointed during the nomination contest, where the demands for money are high but candidates are constrained in their ability to raise funds. Indeed, Super PACs repeatedly outspent Republican candidates and dominated the broadcast airwaves with their advertisements. Yet, as newcomers to the campaign, questions abound of what Super PACs actually do. Are they active in the invisible primary, perhaps playing an important role in winnowing down the field before voters get a chance to weigh in? Do they disproportionately serve the interests of front-runners? Or, do they keep afloat less organized challengers who otherwise would not be able to compete? We respond to these questions with a comprehensive description of Super PAC spending over time and across space, with careful attention to the direction of the outside groups' messages, for or against candidates. In addition to questions of how Super PACs affected the behavior of candidates in the 2012 nomination contest, we also evaluate the legal and arguably more pertinent question, "Are they 'independent?'" A frequent criticism of Super PACs is that their independence from the campaigns is a ruse, as one might expect given that former campaign staff and trusted candidate advisors often work for Super PACs (see, e.g., Confessore 2011). To that end, we focus our efforts on testing whether Super PACs appear to be coordinating their expenditure behavior with candidates and how. We outline and test for two possible forms of coordination. First, campaigns and Super PACs might coordinate their expenditures to complement each other by spending in the same places at the same time, bombarding the airwaves with consistent messages. Alternatively, they might prefer a strategy of substitution whereby PACs and campaigns focus on different locales in which they might be more successful. We test for these two possible forms of coordination by performing a longitudinal analysis that tests the dynamic relationship between candidates and Super PAC spending. In what follows we begin by presenting an overview of the new campaign finance landscape since Citizens United v. Federal Election Commission (FEC) (2010) and discussing the possible implications of the entrance of Super PACs within the party nomination process. We divide the remainder of the article into answering the two sets of aforementioned questions pertaining to the behavior and nature of Super PACs, respectively. …

Using data from the 2008 presidential nomination contest, we offer systematic tests of the relationships between traditional campaign factors, the Internet and campaign performance. We find that claims of the Internet’s relevance to modern campaigns are warranted, as it is a unique facet of campaigns and significantly improves candidates’ financial and electoral support. The Internet is especially helpful to candidates in generating small-donor contributions and in maximizing contributions after early primary victories. Overall, these findings suggest that the Internet offers a viable mechanism for long-shot candidates to overcome the resource demands of the current presidential nomination system.

The presidential nomination process continues to change, and so too does our understanding of which factors drive nomination outcomes. The most recent changes have come in the form of drastic adjustments to the schedule of state contests. Nomination campaigns have become increasingly front-loaded, compressed, and nationalized (Mayer and Busch 2004), making the preprimary campaign, or what is also termed the invisible primary or the exhibition season, a powerful force in the selection of party nominees for president. Indeed candidates for nomination often withdraw in this period, and party nominations are clinched within, what was until recently, mostly shorter and shorter time periods (Haynes et al. 2004; Norrander 2006). Recent scholarship now emphasizes that a candidate's level of funding and national political support at the beginning of the primary season largely determine who wins the nomination (Adkins and Dowdle 2001, 2005; Cohen et al. 2008; Mayer 1996, 2003; Steger et al. 2004; Steger 2007). As a result, long shots have less of a chance to compete with early front-runners (Steger 2000), leading some scholars to conclude that parties have essentially turned back previous electoral reforms (Aldrich 2009; Cohen et al. 2008). While the national invisible primary appears to hold greater importance, the role of the traditional early state bellwethers, Iowa and New Hampshire, is now in doubt. Recent analyses of what predicts nomination success have painted the contribution of New Hampshire as small and Iowa as nonexistent (Adkins and Dowdle 2001; Steger et al. 2004; Steger 2007), to the point some scholars liken these contests to "bumps in the road" (Adkins and Dowdle 2001, 2004). The minor role of these states thus pales in comparison to that of national party endorsements, campaign cash reserves, and national poll standings at the end of the invisible primary period. Although convincing, these findings present a puzzle: why then are candidates still devoting a substantial amount of attention and resources to these contests? (1) We propose that Iowa and New Hampshire continue to be powerful players within nomination contests, because the increasingly visible invisible primary grants these states a different means of influence. National levels of candidate viability and exposure are responsive to the dynamics of these state contests, since long-shot candidates and the media predominately focus on these two states throughout the invisible primary. As a result, the happenings of the Iowa and New Hampshire campaign have an important say within the national invisible primary before the votes in these states are actually tallied. Using data from the 2008 presidential nomination campaign, we evaluate these claims with daily measures of candidate prominence in national news coverage, national polls, and Iowa and New Hampshire polls during the last half of 2007. We accommodate for missing data, sampling error, and reciprocal influences by estimating a Bayesian state space vector autoregression model. We find that a candidate's early performance within Iowa and New Hampshire is equally if not more of a contributing factor to national polls and national media coverage as they are a reaction to them. The subsequent analysis of weekly campaign contribution totals also shows that polling performance within these early states has a strong influence on campaign contributions during the invisible primary that equals the contribution of national polling performance. Although these findings do not dispute the importance of candidates needing sufficient national support entering an election year to win a party's nomination, they provide evidence that states like Iowa and New Hampshire still have a profound but indirect influence on the process. To the extent a candidate can gain early support in these states, they will likely increase their national popular support and campaign contributions before any election is held. …

Can candidates spend their way into financial success? We propose that the 2007 presidential money primary offers unprecedented leverage to evaluate spending’s influence since it allows for sharper controls of confounding factors. Our results demonstrate that greater candidate spending on fundraising-related efforts is associated with significant future financial benefits. We estimate that, prior to the primaries, increases in spending have an equal or larger payoff than increases in a candidate’s viability and find different types of spending are beneficial for frontrunner and long-shot candidates. The results consistently indicate greater early spending works to advantage candidates, suggesting a lack of initial resources is a significant obstacle for candidates who seek to financially benefit from their campaign’s performance.

Few studies examine whether the public agenda responds to different types of issue coverage in the same way. After outlining why such differences are likely, this study takes advantage of daily polling data and a rare sequence of news cycles surrounding the issue of gun control to compare how coverage of different political actors and events drives an issue's placement on the public agenda. Coverage generated by the citizen activist group, the Million Mom March, is estimated to have a greater influence on public opinion compared to coverage of a string of school shootings or, finally, President Clinton's campaign. Tests show that group or political biases do not drive these results but, along with evidence from the 2009 health care protests, coverage of citizen demonstrations consistently outperforms presidential news in its association with the mass public agenda. Although elected officials are granted greater access to news media coverage, the findings suggest that such access does not grant a corresponding influence on the public agenda. More generally, it demonstrates that news storyline content has measurable implications for news media agenda setting at the national level. Language: en

This article uses underutilized individual-level data to examine who supported two third parties, the Grange and Greenbackers, in the final decades of the nineteenth century. We find that Greenbackers attracted individuals employed in non-agrarian occupations and others who were wealthier compared to major party voters. However, the Grange principally appealed to farmers, indicating third parties that are believed to have appealed to similar constituencies often appealed to different electoral groups. Both the Grange and the Greenbackers appealed to voters lacking strong ethnocultural identifications with either major party.

Publication based on research carried out in the framework of the European Union Democracy Observatory (EUDO) of the Robert Schuman Centre for Advanced Studies, European University Institute. The journal issue has been produced in the framework of the PIREDEU Project, one of the projects carried out by the EUDO Public Opinion Observatory. Central to traditionalist and revisionist perspectives of individual-level party identification is a debate about the stability of party identification. We revisit the debate about the dynamic properties and processes underlying party identification. We present a conceptual framework that defines heterogeneity and state dependence as endpoints of a continuum underlying partisan stability, which is important in understanding an individual’s capacity for updating partisanship. Using panel data from the 1992–1996 National Election Study, we estimate dynamic, random effects multinomial logit models of party identification that distinguish between heterogeneity and “true state dependence.” In accord with traditionalist perspectives, our evidence suggests that in general, minimal state dependence underlies party identification; party identification is strongly stationary. However, we find that age enhances the magnitude of state dependence, which provides some support for revisionist theories. Overall, our work showcases how explaining individual-level dynamics expands our knowledge of partisan stability. 1. Stability and party identification 2. Foundations of partisan stability: the heterogeneity and state dependence continuum 3. Data and methods 4. Results 5. Discussion and conclusion Appendix. Supplementary data References

Smidt D, Torpet LA, Nauntofte B, Heegaard KM, Pedersen AML. Associations between oral and ocular dryness, labial and whole salivary flow rates, systemic diseases and medications in a sample of older people. Community Dent Oral Epidemiol 2011; 39: 276–288. © 2010 John Wiley & Sons A/S Abstract – Objective: To investigate the associations between age, gender, systemic diseases, medications, labial and whole salivary flow rates and oral and ocular dryness in older people. Methods: Symptoms of oral and ocular dryness, systemic diseases, medications (coded according to the Anatomical therapeutic chemical (ATC) classification system), tobacco and alcohol consumption were registered, and unstimulated labial (LS) and unstimulated (UWS) and chewing-stimulated (SWS) whole salivary flow rates were measured in 668 randomly selected community-dwelling elderly aged 65–95. Results: Presence of oral (12%) and ocular (11%) dryness was positively correlated. Oral dryness was associated with low UWS, SWS and LS, and ocular dryness with low UWS and SWS. Oral and ocular dryness was related to female gender, but not to age. Only four persons in the healthy and nonmedicated subgroups reported oral and ocular dryness. The numbers of diseases and medications were higher in the older age groups and associated with oral and ocular dryness, low UWS, SWS and LS. On average, women were slightly older, reported more oral and ocular dryness and had lower UWS, SWS, LS and higher numbers of diseases and medications. High prevalence and odds ratios for oral dryness were associated with metabolic, respiratory and neurological diseases and intake of thyroid hormones, respiratory agents (primarily glucocorticoids), psycholeptics and/or psychoanaleptics, antineoplastics, proton pump inhibitors, antidiabetics, loop diuretics, antispasmodics, quinine and bisphosphonates. Ocular dryness was especially associated with neurological diseases and intake of psycholeptics and/or psychoanaleptics. Intake of magnesium hydroxide, antithrombotics, cardiac agents, thiazides, beta-blockers, calcium channel blockers, ACE inhibitors/angiotensin II antagonists, statins, glucosamine, paracetamol/opioids, ophthalmologicals and certain combination therapies was related to oral and ocular dryness. Conclusions: In older people, oral and ocular dryness are associated with low salivary flow rates, specific as well as high number of diseases and medications, but neither with age and gender per se nor with tobacco and alcohol consumption. New detailed information concerning associations between medications and oral and ocular dryness has been obtained using the ATC classification system.

Zusammenfassung Bei 56 prapuberalen Jungsauen wurden durch Injektion von 1000 i. E. PMSG Ovulationen induziert, die Tiere besamt und Ovulationsraten und Plasma-Progesteronwerte wahrend der Praimplantationsphase bestimmt. Uterussekrete wurden am Tag 6, 9 und 12 der Trachtigkeit gewonnen und auf Proteingehalt und Proteinzusammensetzung, speziell in Abhangigkeit zur Superovulation, analysiert. Der Gesamtproteingehalt in der Spulflussigkeit pro Uterus nahm von 13,8 mg am Tag 6 auf 34,9 mg am Tag 9 und 116,5 mg am Tag 12 zu, hatte aber keine engere Beziehung zur Gelbkorperzahl bzw. den Plasma-Progesteronwerten innerhalb von Untersuchungstagen, aber enge Beziehung zum Uterusgewicht am Tag 9 und 12 (r = 0,77 bzw. r = 0,94). Uterusspezifische saure Proteine konnten erst mit Tag 12 im Postalbuminbereich und deutliche breite Bander im Transferrin- und Posttransferrinbereich nach Auftrennung mit Hilfe der Polyacrylamid-Gel-Disk-Elektrophorese dargestellt werden. Der Proteinanteil im Praalbumin- und Albuminbereich am Tag 12 war bei Tieren mit mehr als 16 Corpora lutea erhoht, wahrend die makromolekularen Komponenten im Posttransferrinbereich deutlich geringer ausgepragt waren. In der Uterusspulflussigkeit wurden Progesteron und Ostradiol nachgewiesen. Die Progesterongehalte pro Uterus waren zwischen Tag 6, 9 und 12 konstant, die Durchschnittswerte betrugen 91,7, 94,3 und 79,1 ng/Uterus. Die 17 β-Ostradiolgehalte nahmen dagegen betrachtlich zu (p < 0,01) von 520 pg auf 2154 pg/Uterus; fur Tiere mit mehr als 16 C. l. waren die Ostradiolwerte am Tag 12 signifikant hoher (1245 pg : 2911 pg/Uterus). Es wird vermutet, das freies Ostradiol im Uterus bereits ab Tag 6 von den Embryonen synthetisiert werden konnte und den Eitransport reguliert. Summary Uterine protein secretion in the preimplantation phase in superovulating gilts In 56 prepuberal gilts ovulation was induced by injection of 1,000 i. u. of PMSG, the animals were inseminated and the ovulation rate and plasma progesterone concentration were determined during the preimplantation phase. Uterine secretion was collected during days 6, 9 and 12 of pregnancy and analysed for protein content and composition, especially in relation to superovulation. The total protein content in the wash-out fluid per uterus increased from 13.8 mg. on day 6 to 34.9 mg. on day 9 and 116.5 mg. on day 12, but showed no close relationship with the number of corpora lutea or plasma progesterone levels within the days concerned, but a close relationship with uterine weight on days 9 and 12 (r = 0.77 and 0.94, respectively). Uterus-specific acid proteins were first detected on day 12 in the post-albumin region and clear wide bands in the transferrin and post-transferrin regions after separation with the help of polyacrylamide-gel-disc-electrophoresis. The protein content in the pre-albumin and albumin regions on day 12 was increased in animals with more than 16 corpora lutea, whereas the macromolecular components in the post-transferrin region were noticeably less marked. In the uterine washings progesterone and oestradiol were detected. The progesterone content per uterus was constant between days 6, 9 and 12, the mean values being 91.7, 94.3 and 79.1 mh./uterus, respectively. The 17 β-oestradiol content, on the other hand, increased considerably (p < 0.01) from 520 pg. to 2,154 pg./uterus; for animals with more than 16 corpora lutea the oestradiol values on day 12 were significantly higher (1,245 pg. : 2,911 pg./uterus). It is suggested that free oestradiol is already being synthesized in the uterus from day 6 by the embryos and regulated transport of the egg. Resume Secretion uterine des proteines dans la phase de pre-implantation chez de jeunes truies avec superovulation Des ovulations ont ete induites par injection de 1000 I. E. PMSG chez 56 truies pre-puberes qui ont ete inseminees et on a determine les taux d'ovulation et les valeurs de la progesterone du plasma durant la phase de pre-implantation. On a recueilli les secretions uterines au 6e, 9e et 12e jour de la gestation et on a analyse leur taux en proteines et leur composition en proteines specialement en fonction de la superovulation. Le taux des proteines totales dans le liquide de lavage augmente par uterus de 13,8 mg au 6e jour a 34,9 mg au 9e jour et a 116,5 mg au 12e jour de gestation mais n'a pas de rapport etroit avec le nombre de corps jaunes et les valeurs de la progesterone du plasma durant les jours d'analyse mais un rapport etroit avec le poids de l'uterus au 9e et au 12e jour (r = 0,77 et r = 0,94). Des proteines acides specifiques de l'uterus ont ete representees apres separations par electrophorese sur disques de gel de polyacrylamide au niveau des post-albumines et par de larges bandes nettes au niveau des transferrines et des post-transferrines. La proportion des proteines au niveau des pre-albumines et des albumines au 12e jour fut augmentee chez les animaux ayant plus de 16 Corpora lutea alors que les composants macromoleculaires au niveau des post-transferrines etaient nettement moins etendus. La progesterone et l'oestradiol ont ete mis en evidence dans le liquide de lavage de l'uterus. Les taux de la progesterone par uterus furent constants entre le 6e, 9e et 12e jour, les valeurs moyennes furent de 91,7, 94,3 et 79,1 ng/uterus. Les taux du 17 β-oestradiol augmenterent par contre nettement (p < 0,01) de 520 pg a 2154 pg/uterus. Les animaux ayant plus de 16 Corpora lutea presenterent des valeurs d'oestradiol significativement plus elevees au 12e jour (1245 pg : 2911 pg/uterus). On suppose que l'ostradiol libre dans l'uterus peut etre synthetise par les embryons des le 6e jour deja et qu'il regle le transport de l'oeuf. Resumen La secrecion proteica uterina en la fase preimplantatoria en cerdas jovenes superovuladas En 56 cerdas prepuberes se indujeron ovulaciones mediante la inyeccion de 1.000 u. i. de PMSG, se inseminaron y se determinaron las tasas de ovulacion y los niveles de progesterona plasmica durante la fase de preimplantacion. Recogieronse las secreciones uterinas en los dias 6, 9 y 12 de gestacion, analizandose con respecto al contenido proteico y la composicion de las proteinas, especialmente en dependencia de la superovulacion. Aumento el contenido en proteina total en el liquido de lavado por utero de 13,8 mg. en el dia 6° a 34,9 mg. en el dia 9° y a 116,5 mg. en el dia 12°, pero no existia ninguna correlacion estrecha con la cantidad de cuerpos amarillos resp. con los valores de progesterona plasmica dentro de los dias de examen, aunque si una relacion estrecha con el sobrepeso uterino el dia 9° y 12° (r = 0,77 resp. r = 0,94). Las proteinas acidas especificas del utero solo se pudieron representar el dia 12° en el ambito postalbuminoideo, y bandas anchas claras en el ambito de la transferrina y posttransferrina despues del desdoblamiento con ayuda de la electroforesis en discos de gelosa y poliacrilamida. La fraccion proteica en el ambito prealbuminoideo y albuminoideo en el dia 12° estaba aumentada en los animales con mas de 16 cuerpos amarillos, mientras que eran menos ostensibles los componentes macromoleculares en el ambito posttransferrinico. En el liquido de lavado uterino se identificaron progesterona y oestradiol. Las tasas de progesterona por utero eran constantes durante los dias 6°, 9° y 12°, importando los valores medios 91,7, 94,3 y 79,1 ng./utero. Sin embargo, aumentaron considerablemente los contenidos en oestradiol 17 β (p < 0,01) de 520 pg. a 2.154 pg./utero; para los animales con mas de 16 c. a. eran significantemente mayores los valores de oestradiol el dia 12° (de 1.245 pg. a 2.911 pg./utero). Se sospecha que a partir del dia 6° podria ser sintetizado oestradiol libre por los embriones en el utero, regulando asi el transporte del ovulo.

Zusammenfassung In einer faktoriellen Versuchsanordnung wurden 189 weibliche Mastschweine mit zwei Hormonpraparaten, Progesteron oder Chlormadinon (CAP) in jeweils 3 Dosierungen (Progesteron: 12,5 mg, 37,5 mg, 112,5 mg je Tier und Tag; Chlormadinon: 1 mg, 3 mg, 9 mg je Tier und Tag), 3 Wochen lang behandelt. Je ein Drittel der Tiere wurde am 1., am 8. und 15. Tag nach dem Abbruch der Hormonapplikation geschlachtet. Insgesamt wurden die Organe von 133 Sauen beurteilt. Von diesen Tieren waren 31 v. H. geschlechtsreif. Es wurden folgende Einflusse der Hormonbehandlung festgestellt: 1. Der Synchronisierungsindex betrug mit steigender Dosishohe 0,33, 0,45 und 0,50 bei den mit Progesteron behandelten und 0,08, 0,44 und 0,54 bei den mit CAP behandelten Sauen. 2. Die Hormonbehandlung mit den zwei hoheren Dosierungen der beiden angewandten Praparate resultierte bei den geschlechtsreifen Sauen in einer Synchronisierung des Funktionszustandes der Eierstocke. 3. a) Der Eileiter zeigte einen leichten Einflus der Hormonbehandlung auf die Hohe des Epithels, die Menge an Polysacchariden sowie die Intensitat der Farbung alkalischer Phosphatasen. b) Die Gebarmutter wies in der Hohe und im Glykogengehalt des Oberflachen- und des Drusenepithels deutliche Einflusse der Art des verwendeten Gestagens, der Dosishohe und der Lange des Intervallszwischen Behandlungsende und Schlachtung auf. c) Die Scheide lies in der Hohe des Epithels die weitaus starkste Reaktion auf die Hormonbehandlung erkennen; die hochsten Meswerte ergaben sich bei Tieren aus der Gruppe, welche am achten Tag nach dem Ende der Progesteroninjektionen von 112,5 mg je Sau und Tag geschlachtet waren. d) Unterschiede zwischen Progesteron und Chlormadinon wurden vor allem in einem schwacheren Reboundeffekt nach der Verabreichung von CAP deutlich. Summary Studies on the effects of two gestogenic substances on the reproductive functions and structure of the genital organs of young sows In a factually planned experiment, 189 young fattening sows were given two hormone preparations, progesterone or chlormadinone (CAP) at three different levels (progesterone 12.5 mg., 37.5 mg. and 112.5 mg. per pig per day; chlormadinone 1 mg., 3 mg. and 9 mg. per animal per day) for three weeks. One-third of the animals were slaughtered 1, 8 and 15 days after administration of the hormone had ceased. In all the organs of 133 sows were assessed. Thirty-one per cent of the animals studied were sexually mature. The following results of hormone treatment were obtained: 1. The synchronisation index with increasing dose levels was 0.33, 0.45 and 0.50 for the animals treated with progesterone and 0.08, 0.44 and 0.54 for those treated with CAP. 2. Hormone treatment at the two higher dose levels of both preparations resulted in synchronisation of the functional state of the ovaries in the sexually mature sows. 3. a) The oviduct was slightly influenced by hormone treatment in respect of the height of its epithelium, the amount of polysaccharides and the intensity of staining of alkaline phosphatase. b) The uterus showed in respect of the height and glycogen content of the superficial and glandular epithelium clear effects of the type of gestagen used, the dose level and the time elapsing between treatment and slaughter. c) The vagina showed the greatest reaction to hormone treatment by the height of the epithelium. The highest values were given in animals of the group slaughtered 8 days after progesterone injections of 112.5 mg. per sow per day. d) The differences between progesterone and CAP were clearly recognisable in the form of a weaker rebound effect in the case of CAP. Resume Recherches concernant les effets de deux substances gestagenes sur les fonctions reproductrices et sur la structure des organes genitaux de jeunes truies Dans une disposition experimentale factorielle, on traite 189 truies d'engraissement a l'aide de deux preparations hormonales, la progesterone ou le chlormadinon (CAP), administrees en trois dosages differents (progesterone: 12,5 mg, 37,5 mg ou 112,5 mg par animal et par jour; chlormadinon: 1 mg, 3 mg ou 9 mg par animal et par jour), pendant 3 semaines. On sacrifie chaque fois un tiers des animaux le 1er, le 8eme et le 15eme jour apres arret de l'administration hormonale. On examine au total les organes de 133 truies. 31% de ces animaux se trouvaient a maturite sexuelle. On etablit les influences suivantes du traitement hormonal: 1. L'index de synchronisation par doses croissantes se trouve a 0,33 0,45 et 0,50 pour les truies traitees a la progesterone et a 0,008, 0,44 et, 0,54 pour les truies traitees au CAP. 2. Le traitement hormonal avec les deux dosages plus eleves des deux preparations resulte en une synchronisation de l'etat fonctionnel des ovaires chez les truies a matuite sexuelle. 3. a) La trompe uterine revele une legere influence du traitement hormonal sur la hauteur de l'epithelium, le nombre des polysaccharides, de meme que sur l'intensite de la coloration des phosphatases alcalines. b) Par la hauteur des epitheliums superficiel et glandulaire, de meme que par leur teneur en glycogene, la matrice revele de nettes influences de la sorte de gestagene employee, du dosage et de la duree de l'intervalle entre la fin du traitement et l'abattage. c) Le vagin manifeste par la hauteur de son epithelium la reaction de loin la plus forte au traitement hormonal; on trouve les valeurs les plus elevees chez les animaux du groupe sacrifie le 8eme jour apres la fin des injections de progesterone de 112,5 mg par truie et par jour. d) Les differences entre progesterone et chlormadinon se reconnaissent surtout par un “rebound effect” plus faible apres application de CAP. Resumen Estudios sobre las acciones de dos substancias gestagenas sobre las funciones reproductoras y sobre la estructura de los organos genitales de cerdas juveniles En una disposicion experimental factorial se trataron durante 3 semanas 189 cerdas de engorde con dos especialidades hormonales, progesterona o clormadinona (CAP), en 3 dosificaciones cada vez (progesterona: 12,5 mg, 37,5 mg, 112,5 mg por animal y dia; clormadinona: 1 mg, 3 mg, 9 mg por animal y dia). Cada vez un tercio de los animales se sacrificaron el 1er, enjuiciaron los organos de 133 cerdas. El 31% de estos animales eran puberes. Se comprobaron los influjos del tratamiento hormonal siguientes: 1. El indice de sincronizacion ascendia con dosis creciente a 0,33, 0,45 y 0,50 en las cerdas tratadas con progesterona y a 0,08, 0,44 y 0,54 en las tratadas con CAP. 2. El tratamiento hormonal con las dos dosificaciones mas elevadas de ambas especialidades empleadas resultaba en las cerdas puberes en una sincronizacion del estado funcional de los ovarios. 3. a) El oviducto mostraba un influjo ligero del tratamiento hormonal sobre la altura del epitelio, la cantidad de polisacaridos, asi como la intensidad de coloracion de las fosfatasas alcalinas. b) El utero evidenciaba en la altura y en el contenido glucogenico del epitelio superficial y del glandular influjos claros del tipo del gestageno empleado, de la dosis y la longitud del intervalo entre el final del tratamiento y la matanza. c) La vagina permitia reconocer en la altura del epitelio la reaccion bastante mas marcada frente al tratamiento hormonal; los valores de medicion mas elevados se obtuvieron en los animales pertenecientes al grupo que se sacrifico el 8° dia despues de terminar las inyecciones de 112,5 mg de progesterona por cerda y dia. d) Se hicieron patentes las diferencias entre la progesterona y la clormadinona, ante todo en un efecto de rechazo mas debil, tras la administracion de CAP.

Zusammenfassung 1 Es wurden Versuche zur Vorbeuge der Saugferkelanamie durchgefuhrt mit einem Praparat, welches 6 bis 7 % Eisen in Form von Eisenfumarat, gebunden an eine Tragersubstanz, enthalt. Es wird den Ferkeln zur freien Aufnahme in einem Schalchen bereitgestellt. 2 Die Ferkel nehmen das Praparat vom ersten Lebenstage an gern auf. 3 Die Wirkung des bei 33 Wurfen des veredelten Landschweines eingesetzten Eisenfumarats wurde an der bekannten positiven Wirkung der Myofer-Injektion gemessen. Zum Vergleich standen 29 Myofer-Wurfe zur Verfugung. Der Verbrauch betrug in Wurfen durchschnittlicher Grose (10 Ferkel) etwa 1 kg des Eisenfumarat-Praparates. Die Hamoglobinwerte, festgestellt nach der 1., 2. und 3. Lebenswoche, betrugen bei der Fe-Fumarat-Zugabe 10,10, 10,66 und 10,49 g % im Durchschnitt gegenuber 10,86, 11,65 und 11,62 g % in den Myofer-Wurfen. Hinsichtlich der Gewichtsentwicklung und Ferkelverluste konnten ebenfalls keine wesentlichen Unterschiede zwischen den genannten Gruppen ermittelt werden. 4 Bei den auf dem Versuchsgut Friedland fur Laboratoriumszwecke gezuchteten Zwergschweinen wurde Eisenfumarat an insgesamt 65 Wurfe verabreicht, 22 Wurfe erhielten eine Myofer-Injektion, wahrend 10 Kontrollwurfe ohne zusatzliche Eisenversorgung blieben. Die an 25 Fumarat-Wurfen, 18 Myofer-Wurfen und 10 Kontrollwurfen nach der 1., 2. und 3. Lebenswoche festgestellten Hamoglobinwerte zeigten folgendes Bild: Wahrend die Hb-Werte in den Myofer- und Fumarat-Wurfen einander in etwa entsprechen, sind diese bei den Kontrolltieren stark abgesunken, jedoch ist der negative Einflus fehlender zusatzlicher Eisenversorgung offenbar nicht so stark wie bei veredelten Landschweinen. Die an 22 Myofer-, 65 Fumarat- und 10 Kontrollwurfen verfolgte Gewichtsentwicklung ergab gewisse Vorteile fur die Fumaratgruppe. Es ergaben sich jedoch keine Anhaltspunkte dafur, das der Zwergwuchs zu einem gewissen Teil auf Eisenmangel zuruckzufuhren ist. Die Verabreichung von Fe-Fumarat an 33 Zwergschweinwurfe uber einen Zeitraum von 8 Wochen ergab gegenuber einer dreiwochigen Zugabe keinerlei Vorteile. 5 Die Eisenversorgung der Saugferkel mit Eisenfumarat ist einfach durchzufuhren und wenig arbeitsaufwendig. Die Kosten sind mit etwa 5,00 bis 8,00 DM fur die Versorgung eines Wurfes vergleichsweise gering.

Background: Oral lichen planus (OLP) is a chronic mucosal disease with a characteristic clinical phenotype. Environmental exposures, e.g. drugs have been associated with the pathogenesis. Objectives: To test the hypothesis that some OLP lesions have a pharmacological pathogenesis related to polymorphisms of the cytochrome P450 enzymes (CYPs) resulting in poor or intermediate CYP metabolism. Methods: One hundred and twenty patients with OLP and 180 gender-matched controls without OLP were genotyped for CYP2C9, CYP2C19, and CYP2D6 alleles with absent or reduced function. Results: The prevalence of poor or intermediate metabolizers was not higher among the OLPs as compared with the controls; however, there were higher numbers of variant CYP2D6 genotypes among the OLP females (P

Biotechnology is a key technology in the generation of an adequate food supply for the ever growing human population. Genetics and reproduction as fundamental functional prerequisites for successful livestock production have been important subjects of biotechnological research in animal science for many decades. Biotechnological procedures developed so far are to be applied for increasing breeding efficiency in farm animals, for the preservation of animal genetic resources, for the improvement of product quality or for new production strategies and novel animal products. Many of these opportunities are already routine in animal husbandry, others will be employed according to needs, suitability and their public perception. The latter has to be addressed by observing the ethical principles for the application of biotechnology in animals in selected areas of livestock production in which immediate benefits are to be obtained. This paper deals with some of the future perspectives and visions for animal biotechnology in research and field application. It focusses on cryopreservation of germ cells and embryos, ovum pickup from ovaries in situ and IVMFC, gender preselection, cloning, genome analysis and gene mapping, and gene transfer.

To investigate the associations between age, gender, systemic diseases, medications, labial and whole salivary flow rates and oral and ocular dryness in older people.Symptoms of oral and ocular dryness, systemic diseases, medications (coded according to the Anatomical therapeutic chemical (ATC) classification system), tobacco and alcohol consumption were registered, and unstimulated labial (LS) and unstimulated (UWS) and chewing-stimulated (SWS) whole salivary flow rates were measured in 668 randomly selected community-dwelling elderly aged 65-95.Presence of oral (12%) and ocular (11%) dryness was positively correlated. Oral dryness was associated with low UWS, SWS and LS, and ocular dryness with low UWS and SWS. Oral and ocular dryness was related to female gender, but not to age. Only four persons in the healthy and nonmedicated subgroups reported oral and ocular dryness. The numbers of diseases and medications were higher in the older age groups and associated with oral and ocular dryness, low UWS, SWS and LS. On average, women were slightly older, reported more oral and ocular dryness and had lower UWS, SWS, LS and higher numbers of diseases and medications. High prevalence and odds ratios for oral dryness were associated with metabolic, respiratory and neurological diseases and intake of thyroid hormones, respiratory agents (primarily glucocorticoids), psycholeptics and/or psychoanaleptics, antineoplastics, proton pump inhibitors, antidiabetics, loop diuretics, antispasmodics, quinine and bisphosphonates. Ocular dryness was especially associated with neurological diseases and intake of psycholeptics and/or psychoanaleptics. Intake of magnesium hydroxide, antithrombotics, cardiac agents, thiazides, beta-blockers, calcium channel blockers, ACE inhibitors/angiotensin II antagonists, statins, glucosamine, paracetamol/opioids, ophthalmologicals and certain combination therapies was related to oral and ocular dryness.In older people, oral and ocular dryness are associated with low salivary flow rates, specific as well as high number of diseases and medications, but neither with age and gender per se nor with tobacco and alcohol consumption. New detailed information concerning associations between medications and oral and ocular dryness has been obtained using the ATC classification system.

Estimators within the Cox family are often used to estimate models for repeated events. Yet, there is much we still do not know about the performance of these estimators. In particular, we do not know how they perform given time dependence, different censoring rates, and a varying number of events and sample sizes. We use Monte Carlo simulations to demonstrate the performance of a variety of popular semi-parametric estimators as these data aspects change and under conditions of event dependence and heterogeneity, both, or neither. We conclude that the conditional frailty model outperforms other standard estimators under a wide array of data-generating processes, and data limitations rarely alter its performance.

Calves of the dairy herd were used for this investigation. Body weight and growth rate were measured at 4, 6, 10, 12 and 13 weeks of life and venous blood acid base status, gas content, creatinine, urea, total protein, Ca, Mg, P, Na, K, Cl, Fe and catecholamine content at 15 days and at 90 days of age as well. Changes of blood values were analyzed in connection with growth performance and with the blood values of calves at 15 days of age testing the individually different degrees of adaptation and development.

Dairy calves and their dams from the dairy herd of the institute were used for this investigation. Calvings were watch carefully and jugular venous blood samples taken immediately after delivery from the cow and the calf and in the calf at 24 hours and at 48 hours of postnatal age as well were analyzed for T4, FT4, T3 and FT3 by luminescence enzyme immunoassay (LEIA). Higher thyroid values in calves than in their dams could be found increasing short after birth and reaching their highest level within 24 hours of postnatal life. The individual thyroid hormone values at birth and at 24 hours and at 48 hours of age are well correlated meaning the changes during the first days are specific for each calf. Strong correlation between the thyroid hormone values of the cows and those of the calves could be found. Mean values of thyroid hormones were significantly higher in female than in male calves all time but not different in the dams of these calves.

Suckler calves of the mother cow herd were used for this investigation. Body weight, growth rate and venous blood acid base status, gas content, creatinine, urea, lactate, total protein, albumin, Ca, Mg, Na, K and Cl were measured at 20, 60 and 90 days of postnatal life. Body weight and growth rate showed strong correlations with some blood values especially at 60 and 90 days of age meaning that adaptation is performed successful in some calves and incomplete in others. Disproportionate growth of body parts and the limited oxygen-carrying capacity below the oxygen needs of the tissues may cause the great lactate values in some calves of all age groups.

In 11 heifers originating from one mother cow herd and in their offspring delivered by cesarean section heart rate recordings were taken during their staying in the calving box and later on in group housing. Heart rate showed a rhythmicity in accordance with behavioural physiological reactions. The mean heart rate of a 24 hour period in an animal was different between and within the newborn and elder animals. The mean heart rate was increasing in the calves during the first days of their postnatal life and decreasing in the mother cows within some days after parturition. Blood samples taken repeatedly in 9 heifers via an indwelling catheter and in their offspring short after birth and at 24 and 48 hours by venipuncture as well were analysed for acid-base status, cortisol, noradrenaline, adrenaline, hemoglobin and lactate. Comparing the results with other investigations can be used for evaluating the strain of delivery by cesarean section for the young and the mother as well as revealing main influences on the reactions of the animals and their individual specificity.

The heart rate measured continuously in grazing cows over 24 hours is significantly different during specific behavioural patterns of an animal and is influenced by the stage of pregnancy of the cow. Repeated measurements of blood urea, creatinine, total protein, albumin and glucose concentration in these animals permit conclusions about the changes of body weight and of the liver function and hormonal integration of energy substrate supply. Living on pasture during the summer period the cows showed the lowest hemoglobin content and hematocrit level of the blood, which increased when the animals were housed in autumn or when near the end of their final trimester of pregnancy. Important differences, especially in the blood values, were found between the groups and within the groups between younger and older cows.

Blood samples taken repeatedly from dairy cows on pasture (50 Holstein-Friesian) and then from 181 cows and their newborn calves within 5 to 10 min after birth were used for measurement of haemoglobin content (Hb). Hb decreased with ongoing lactation and pregnancy, increased several weeks before parturition and reached its highest value shortly after birth. There was some individual, breed and age specificity of Hb in dairy cows. Assisted calvings using marked traction resulted in no difference in Hb values of the cows when compared to other calvings; whereas the calves' Hb values were smaller and the difference between calf Hb and cow Hb was greater. A strong correlation between Hb of the cow and Hb of the newborn calf and the difference Hb calf-Hb cow could be found.

Reactor safety is given by the reliable solution of 3 tasks: on-time shutdown, continuous decay-heat removal, safe containment. After describing the general strategy of their solution even under upset conditions the most important engineered safeguards of pressurized water reactors are summarized. The important problem of human failure is discussed in some more detail. For the example Harrisburg some difficulties, but also some technical countermeasures are illustrated.

Inhalt: Es wurden die Beziehungen zwischen Ovulationsraten, speziell der Superovulation, und den Plasma-Progesteronwerten auf die Embryonalentwicklung der Jungsauen untersucht. Nach Injektion von 1000 i. E. PMSG wurden bei prapuberalen, etwa 180 Tage alten Jungsauen, i. D. 22,4 Ovulationen (5–45) induziert. Die Untersuchungen erfolgten an den Tagen 4, 5, 6 und 9 nach der Besamung. 82% der Eier wurden ausgespult, Ovulationsrate und PPW waren auf die Wiederfindungsrate ohne Einflus. Am 4. Tag nach Besamung befanden sich alle Eier und Embryonen im oberen Drittel des Uterus. Ab Tag 5 erfolgte die Weiterwanderung in die distalen Uterusabschnitte, die endgultigen Implantationsorte waren bis Tag 9 noch nicht erreicht. Hohe Plasma-Progesteronwerte haben Transport und Verteilung der Emhryonen nicht becinfluβt; wahr-scheinlich wird die Eiwanderung durch freies Ostradiol im Uterussekret gesteuert. Uber 97%der Eier waren befruchtet, aber nur 88 % der Embryonen waren normal entwikkelt, d. h. hatten das erwartete Entwicklun, gsstadium erreicht; 4,2 % i. D. waren in der Entwicklung zuruckgeblieben, nach Tag 5 waren nur noch wenig Embryonen abgestorhen. 2 Degenerationsformen waren nur schwer einzuordnen: “fragmentare Eier” und “vermutlich polysperme Ova”. Fruh abgestorbene Embryonen und polysperme Ova kamen fast ausschlieplich bei Tieren mit mehr als 30 Gelbkorpern vor (12 % bzw. 19,6 %) und vor allem bei Tieren (mit 20,7 bzw. 35,5 %), die am Tag 1 oder 2 nach Besamung etwa 3–fach hohere Progesteronwerte aufwiesen als Tiere mit normalen Ovulationsraten. Bei mehr als 30 C. l. ergaben sich somit Eiverluste zwischen 30 und 50 %, wahrscheinlich verursacht durch ein ungunstiges Tubenmilieu und sehr hohe Progesteronwerte wahrend oder kurz nach der Ovulation. Contents: Effects of superovulation and high plasma progesterone on the embryonic development during the preimplantation period in gilts. II. Egg migration and loss of ova. The relationship between ovulation rate and plasma progesterone concentration (PP) on the embryonic development during the implantation period was studied in 73 superovulated gilts. Ovulation was induced with 1000 I. U. PMSG producing a mean ovulation rate of 22.4 corpora lutea (C. L.), range 6–45 C. L. The animals were slaughtered and examined at day 4, 5, 6, 9 and 12 after insemination. Egg recovery was 82 % with no influence of C. L. and PP. At day 4 all ova were found in the upper third of the uterine horns. Migration into the distal parts of the uterus began at day 5 but was not yet completed at day 9. Egg transport and location of the embryos were not influenced by plasma progesterone, but probably by estradiol, which was found in the uterine fluids during this period. Of 808 ova and embryos analyzed 87.5 % were normal, 2.4 % were definitely unfertilized and 10.2 % were degenerated or not at the expected stage of development. Egg loss was mainly observed before day 5, the losses were low (1 %) between day 6 to 9. Two types of egg degeneration were observed, which were difficult to categorize: “fragmented ova” and presumably “polyspermic ova”. These were likely to be caused by impairment of fertilization. Degenerated embryos and polyspermic ova were seen almost exclusively in animals with more than 30 C. L. (12 % and 19.6 %), especially in gilts with PP 3 times higher at day 1 or 2 after insemination (20.7 % resp. 35.5 %), than in gilts with normal ovulation rates (0.8 % resp. 1.2 76). The total loss of eggs in gilts with more than 30 C. L. varied between 30–50 %, probably depending on an unfavourable tubal environment, which is caused by the extremely high progesterone levels during or immediately after ovulation.

Endocrine and physiological events that precede and accompany parturition in the sow occur in a sequential fashion starting with a slow increase in estrogens from about three weeks prior to parturition. The luteotrophic role of LH visible as a distinct LH-progesterone relation is present at three weeks prior to parturition but can no longer be seen at one to two days prior to expulsion. Progesterone has not completed its decline during expulsion. A rather sharp and transient increase in plasma relaxin is known at about one day prior to expulsion. Corticosteroids are elevated also during the last 24 hours before parturition with a peak during expulsion. Oxytocin levels remain at baseline levels till progesterone has reached values below 10 ng/ml when a two step sharp increase in plasma oxytocin can be observed; one step prior to expulsion and a second during expulsion. Concomitant to endocrine changes the uterine EMG displays characteristic patterns, but is insensitive to oxytocin four days prior to parturition.

In meat producing farm animals fertility is one of the most important traits. They should breed again after delivery as soon as possible for economic reasons. In sheep difficulties can be seen due to the seasonal dependency of sexual activity. Their sexual behaviour is, however, influenced by geographical location and breed. In the Institut fur Tierzucht un Tierverhalten, Mariensee, 30 km north of Hannover, seven groups of ewes of different genetic origin were surveyed for estrus appearance through a one year cycle. The animals were not mated to a ram in order to avoid an interruption of the new estrus cycle by pregnancy. Breed differences were apparent in the duration of unestrus during summer time. It was shortest in the Finnish landrace and Merino x Mountain breed crosses and longest in a small local native breed from the heather region. All other groups (German Blackface, Texel and crosses of these two with Finnish Landrace) were intermediate. The number of estrus cycles per ewe and year vari...

The propagation of local subassembly failures is considered one of the possible causes for core disruptive accidents (CDA) in liquid metal fast breeder reactors (LMFBRs). Failure to detect local blockages by the delayed neutron detection system or by the thermocouples located at the fuel element outlet may result in subassembly molten fuel-sodium interactions with the potential to put into the core positive reactivity or reduce the shutdown capacity. In the SNR 300 there are three important inherent or engineered barriers to prevent this type of accident: the early detection of local blockages, the proof of low probability of subassembly boiling and dryout, and the proof of the inherent ability to withstand the pressure pulses caused by molten fuel-sodium interactions. It is concluded that it will be possible to demonstrate that the probability of CDAs caused by local failure propagation is very low.