255 research outputs found
Evaluation of genetic diversity of flowering dogwood (Cornus florida L.) in the eastern United States using microsatellites.
Flowering dogwood (Cornus florida L.) populations have experienced severe declines caused by dogwood anthracnose in the past three decades. Mortality has ranged from 48 to 98%, raising the concern that genetic diversity of this native tree has been reduced significantly. Microsatellite data were used to evaluate the level and distribution of genetic variation throughout much of the native range of the tree. In the first conducted study, we found that genetic variation in areas affected by anthracnose was as high as or higher than areas without die-offs. We found evidence of four widespread, spatially contiguous genetic clusters. However, there was little relationship between geographic distance and genetic difference. These observations suggest that high dispersal rates and large effective population sizes have so far prevented rapid loss of genetic diversity. The effects of anthracnose on demography and community structure are likely to be far more consequential than short-term genetic effects.
The second study examined levels and distribution of genetic variation of C. florida throughout Great Smoky Mountains National Park (GSMNP). Significant genetic structure at both landscape and local levels were found. We infer that two genetic clusters exist within the park, mostly separated by the main dividing ridge of the Great Smoky Mountains. The differentiation is statistically significant, but subtle, with gene flow evident through low-elevation corridors. It seems unlikely that recent demographic dynamics have resulted in a depletion of genetic variation in flowering dogwoods
Institutionally Embedded Democratic Equalizers: Differential Political Involvement Effects of Voluntary Associations across Language Regions in Switzerland
Relying on the data of the Swiss Household Panel, the paper examines to what extent expressive, instrumental, and advocacy voluntary associations equalize the level of political involvement across language regions in Switzerland. Empirical evidence reveals that the positive effects of associations are consistently more pronounced in Latin cantons than in German ones. The differential can be traced back, on the one hand, to the lower engagement in political life among citizens in Latin cantons, which gives them greater leeway to increase it as a consequence of associational involvement. On the other hand, members within associations of the same type show very similar political participation levels across regions. Members pull participation among newcomers in Latin cantons to levels similar to those of their German-speaking counterparts. The size of these equalizing effects can be linked to internal dynamics specific to each associational type and to some features of the Swiss federal state.Anhand der Daten des Schweizer Haushalt-Panels untersucht das Paper, inwieweit expressive Vereine, instrumentelle Vereine und Vereine zur Verteidigung öffentlicher Interessen das Niveau des politischen Engagements in den Sprachregionen der Schweiz einander angleichen. Empirische Resultate zeigen, dass die positiven Effekte von Vereinen auf politisches Engagement in lateinischen Kantonen durchweg stärker ausgeprägt sind als in deutschen Kantonen. Einerseits lässt sich dieser Unterschied auf das geringere politische Engagement der Bürger in lateinischen Kantonen zurückführen, das ihnen einen grösseren Spielraum gibt, dieses als Folge des Vereinsengagements zu erhöhen. Andererseits zeigen die Mitglieder innerhalb von Vereinen desselben Typs zwischen unterschiedlichen Sprachregionen sehr ähnliche politische Beteiligungsniveaus. In den lateinischen Kantonen ziehen die Mitglieder die Neulinge auf ähnliche Partizipationsniveaus wie ihre deutschsprachigen Pendants. Interne Dynamiken, die für jeden Verbandstyp spezifisch sind, sowie Merkmale des Schweizer Bundesstaates können mit dem Ausmass dieser angleichenden Effekte in Verbindung stehen.En utilisant les données du Panel suisse de ménages, l’article examine dans quelle mesure les associations expressives, instrumentales et de défense des intérêts publics égalisent le niveau d’engagement politique entre les régions linguistiques suisses. Les effets positifs des associations sont systématiquement plus prononcés dans les cantons latins que dans les cantons allemands. Cette différence s’explique, d’une part, par l’engagement plus faible dans la vie politique des citoyens des cantons latins, leur donnant une plus grande marge de manœuvre pour l’augmenter en conséquence de l’engagement associatif. D’autre part, les membres d’associations du même type affichent des niveaux de participation politique très similaires entre régions linguistiques. Les membres attirent les nouveaux arrivants dans les cantons latins vers des niveaux de participation similaires à ceux de leurs homologues germanophones. L’ampleur de ces effets égalisateurs est liée à des dynamiques internes propres à chaque type d’association et à certaines caractéristiques de l’État fédéral suisse.Introduction: Supplying and shaping active citizens Theoretical framework: Federally embedded schools of democracy? Data and methodological approach: The upsides of a longitudinal perspective Results: Heterogeneous effects and the reasons behind them Discussion: Homogeneous democratic islands Concluding remarks: Inside associational types and beyond Switzerland Acknowledgements Biography Open research Supporting information Reference
In Vitro Regeneration of Cladrastis kentukea (American yellowwood) and Cornus kousa (kousa dogwood)
Selection of superior individuals followed by clonal vegetative propagation is a very important strategy for plant improvement. Cloning via tissue culture can produce a population of an identical genotype without limits. A single specimen tree of Cladrastis kentukea and five different Cornus kousa cultivars were selected for tissue culture studies. These trees exhibited superior performance in horticultural trials, including disease resistance and drought tolerance, which are highly important to the green industry.
Axillary buds from a single C. kentukea tree were initially cultured on either Woody Plant Medium (WPM) or Murashige and Skoog (MS) containing 0, 1, 2, or 4 μM 6–benzylaminopurine (BA). Cultures were transferred to fresh medium every four weeks. Elongated shoots were harvested after thirty-nine weeks and transferred to half-strength MS medium supplemented with following concentrations of IBA: 0, 3, 30, 100, and 300 μM for three days then returned to half-strength MS without growth regulators. Explants exposed to 300 μM of IBA produced significantly more roots (75%) compared to explants exposed to other treatments. Fifty- four and forty- six percent of the microshoots rooted when exposed to 100 and 30 μM IBA, respectively. Only 4% of the microshoots rooted when exposed to 3 μM IBA and none of the microshoots in the control treatment (0 IBA) rooted. Although 300 μM treatment yielded the most rooted plantlets, there was significantly higher terminal meristem abortion compared to other treatments. There were no statistical differences between the numbers of roots and total root length among all treatments. Additionally, all microshoots that rooted had lenticels, suggesting that presence of lenticel cambial activity can possibly predict rooting abilities of selected microshoots. Rooted microshoots were gradually acclimatized to non-sterile environment.
Axillary and apical buds from five Cornus kousa cultivars (‘Little Beauty’, ‘Samaritan’, ‘Heart Throb’, ‘Rosabella’ and ‘Christian Prince’) were initially established on either WPM or one-half Woody Plant Medium/Broad Leaved Tree Medium (BW), amended with the following concentrations of 6–benzylaminopurine (BA): 0, 2, 4, and 8 μM. After explants were transferred at four-week intervals for 28 weeks beginning in April, only microshoots of ‘Samaritan’, ‘Heart Throb’, and ‘Rosabella’, were harvested from proliferating cultures and placed on rooting media. ‘Little Beauty’ and ‘Christian Prince’ did not perform well in multiplication phase of tissue culture and were excluded from further studies. Rooting media contained WPM or BW supplemented with either 1- naphthaleneacetic acid (NAA), indole-3-butyric acid (IBA), or indole-3-acetic acid (IAA) at the following concentrations: 0, 0.5, 1.5, 4.5, and 13.5 μM. Six weeks following rooting experiment, preliminary data was collected and results indicated a total of nine plants rooted on both WPM and BW media supplemented with IBA, 17 plants rooted on media supplemented with NAA, and 14 plants rooted plants supplemented with IAA. NAA and IAA appeared to be better for root production on C. kousa cultivars microshoots than IBA. Moreover, both WPM and BW media supported rooting of C. kousa microshoots. However, WPM appears to support more root production compared to BW. A greater number of ’Samaritan’ and ‘Heart Throb’ microshoots rooted on WPM amended with a wide range of NAA concentrations, whereas more ‘Rosabella’ microshoots rooted on BW medium amended with various concentrations of IAA. Since ‘Rosabella’ and ‘Heart Throb’ are very closely related and should have rooted with similar treatments, further research is needed to confirm this finding. Additionally, microshoots placed on either basal media supplemented with NAA produced significant amount of callus compared to microshoots exposed to other growth regulator treatments. The highest mean number of roots per rooted microshoot was recorded on ‘Samaritan’ when exposed to various NAA concentrations. In conclusion, the most and best rooting occurred with IBA treatments at lower concentrations, 0.5 and 1.5 μM, whereas NAA and IAA treatments were inconclusive
Der kuriose Fall des mürrischen Gewerkschaftsmitglieds
Relying on the data of the Swiss Household Panel, the paper aims to make sense of the puzzling dissatisfaction union members exhibit in most dimensions of their job. A longitudinal approach reveals that the dissatisfaction is to a large extent explained by contextual and individual time-invariant unobserved heterogeneity. A decline in job satisfaction is for many workers the main reason to join a union. Job satisfaction climbs back as the years of membership increase, which confirms that unions do indeed have positive effects on the professional well-being of their members.En utilisant les données du Panel suisse de ménages, le papier vise à rendre compte de l’étonnante insatisfaction des membres syndicaux dans la plupart des aspects de leur travail. Une approche longitudinale révèle que l’insatisfaction s’explique dans une large mesure par l’hétérogénéité non-observée entre membres et non-membres au niveau contextuel et individuel. Une baisse de la satisfaction au travail est pour de nombreux travailleurs la principale raison d’adhérer à un syndicat. La satisfaction au travail remonte à mesure que le nombre d’années d’adhésion augmente, ce qui confirme que les syndicats ont effectivement des effets positifs sur le bien-être professionnel de leurs membres.Anhand der Daten des Schweizer Haushalt-Panels beabsichtigt das Paper die rätselhafte Unzufriedenheit von Gewerkschaftsmitglieder in den meisten Dimensionen ihrer Arbeit zu erklären. Ein longitudinaler Ansatz zeigt, dass die Unzufriedenheit weitgehend durch kontextuelle und individuelle zeitinvariante, unbeobachtete Heterogenität erklärt wird. Ein Rückgang der Arbeitszufriedenheit ist für viele Arbeiter der Hauptgrund für den Beitritt zu einer Gewerkschaft. Die Arbeitszufriedenheit steigt während der Mitgliedschaftserfahrung zurück, was bestätigt, dass Gewerkschaften tatsächlich positive Wirkungen auf das berufliche Wohlergehen ihrer Mitglieder haben
The Basics of Splinting in Dentoalveolar Traumatology
Dentoalveolar trauma is considered an emergency condition and is challenging for every dentist. As primary and permanent teeth may suffer repercussions from an injury, a therapist must be mindful of which situations the use of splinting methods is required. In dentistry, a splint is a rigid or flexible device with the function of supporting, protecting, and immobilizing teeth that have been weakened (endodontically, periodontally), traumatically injured, replanted, or fractured. Generally, splinting is not recommended for primary teeth injuries such as luxation and avulsion. In permanent dentition, splint appliances are indicated for periodontal injuries, such as subluxation, luxation and avulsion, and hard tissue injuries such as class IV root fractures. Nowadays, there are many appliances that may be used for immobilization of traumatized teeth. Since this issue may sometimes be confusing for dental practitioners, this chapter deals with splint classification (rigid and flexible), the basic characteristics of splints, the indications, and methods of application
Teaching Neural Networks to Classify the Authors of Texts
A lot of research has been done on author classification using various methodologies. One of them is using artificial neural networks. It is common that the number of descriptors used for author classification exceeds two. In this paper we propose a means of using artificial neural network to classify the authors of texts using only two descriptors: the number of words in a paragraph and a number of characters per word in a paragraph. The approach taken uses committee machines based on ensemble averaging. The basic idea is to solve the complex computational task by dividing it into a number of computationally simple tasks and then combining the solution of these tasks. The high performance achieved is because the committee is much better than the single best constituent in the isolation. Our results show that with the above approach we succeeded to correctly classify the works of Leo Tolstoy and George Orwell
Rationalizing the Irrational: Making Sense of (In)consistency among Union Members and Non-Members
Focusing on 13 OECD countries over 25 years, we examine the factors that explain why a sizable fraction of wage-earners exhibit an inconsistency between their union membership status and their confidence in unions by being either confident non-members or non-confident members. While structural factors associated with joining constraints generate inconsistency in specific labour market categories, wage-earners who have extreme ideological orientations and are highly interested in politics are much less likely to exhibit inconsistency across time and countries. For individuals who have intermediate ideological orientations and are not very interested in politics, differences in terms of non-member and member inconsistency between countries are explainable through contextual variables such as economic conditions, the level of employment protection, and historical legacies. Implications for union membership research and union strategies are discussed.Diverging membership and confidence trends: Introduction At the sources of inconsistency: Theoretical background Empirical strategy: Data and methodology Descriptive and explanatory angles: Results Inconsistently inconsistent empirical patterns: Discussion Moody members versus hopeful outsiders? Conclusions Acknowledgements Notes Reference
Is the Left Right? The Creeping Embourgeoisement of Social Democracy through Homeownership
Recent decades have been marked by the rise of populism, the emergence of New Labour and decline of social democratic parties. The dominant explanation for these trends is a shift in cultural attitudes but leaves open where such a sudden shift comes from. Advancing recent cross-sectional work on the political economy of housing, this paper suggests that slow-moving underlying processes as materialized in the expansion of homeownership can help explain the observable cultural shift and recent macrotrends. Taking a longitudinal micro-perspective of individuals’ housing and political trajectories in Germany, Switzerland and the United Kingdom since the 1980s, we find that the transition into homeownership has made voting for social democrats and populists more likely. The influence never comes as a shock but extends over decade-long anticipation and socialization intervals. Rather than strengthening traditional conservative parties, expanding homeownership, we argue, has contributed to the gradual embourgeoisement of the left.New partisan swings and the role of homeownership: Introduction Partisan preferences and homeownership: Theoretical framework Operationalizing the longitudinal perspective: Data and methodology Main and heterogeneous attitudinal trajectories: Empirical findings Non-shocker: Discussion It takes time: Conclusion Acknowledgements Supporting information Reference
Classification of chromosomes using nearest neighbor classifier
This paper addresses automated classification of human chromosomes using k nearest neighbor classifier. k nearest neighbor classifier classifies objects according to the closest training sample in the feature space. Various distance functions can be used in computation of how close the object is to the training sample. In this work various different distance functions are used to compare the performance of each. It was found that Euclidean distance function produces the best results
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