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Daniel J. Peppe - One of the best experts on this subject based on the ideXlab platform.
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Fort Union Formation Fossil Leaves (Paleocene, Williston Basin, North Dakota, USA) Indicate Evolutionary Relationships Between Paleocene and Eocene Plant Species
Bulletin of the Peabody Museum of Natural History, 2014Co-Authors: Daniel J. Peppe, Leo J. HickeyAbstract:Abstract Six fossil leaf species are described from impression fossils collected from the Paleocene Fort Union Formation in the Williston Basin in southwestern North Dakota, USA. They are Meliosma vandaelium sp. nov., Meliosma thriviensis sp. nov., Ternstromites paucimissouriensis sp. nov., Macginitiea nascens sp. nov., Dicotylophyllum horsecreekium sp. nov. and Dicotylophyllum hansonium sp. nov. These species represent some of the elements of the Fort Union Formation that are biostratigraphically important megafloral zone taxa or are species that demonstrate an evolutionary relationship to floras from the Eocene Golden Valley Formation. Some of the species described here suggest that new species endemic to the Williston Basin evolved through the Paleocene and into the Eocene. If the pattern of the origination of endemic daughter species seen in the Williston Basin is consistent across the Western Interior basins of North America, it might have driven up gamma diversity through the Paleogene. This provide...
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Magnetostratigraphy of the Ludlow Member of the Fort Union Formation (Lower Paleocene) in the Williston Basin, North Dakota
Geological Society of America Bulletin, 2006Co-Authors: Daniel J. Peppe, David A.d. Evans, A.v. SmirnovAbstract:To determine the geomagnetic polarity stratigraphy and the duration and age of the Ludlow Member of the Fort Union Formation (Lower Paleocene), we constructed a 325 m composite lithostratigraphic section of the Upper Cretaceous Hell Creek Formation and the Lower Paleocene Ludlow and Tongue River Members of the Fort Union Formation in the Little Missouri River valley of North Dakota, USA. We analyzed paleomagnetic samples from nine of the logged sections. The principal magnetic carrier in the Ludlow Member sediments is likely titanomaghemite, as indicated by predominantly irreversible thermomagnetic curves measured from sandstone, siltstone, and carbonaceous shale samples. The analyzed paleomagnetic samples document a series of polarity zones that can be correlated from C29n to C27r on the geomagnetic polarity time scale (GPTS). We infer that the magnetization of the samples is primary because the characteristic directions are consistent with those of the Paleocene of North America, and the reversal stratigraphy from this section corresponds to the GPTS with reasonable sediment accumulation rates. By extrapolating the measured sediment accumulation rate from the Cretaceous-Tertiary (K-T) boundary to the top of C28n and then to the top of the Ludlow Member, we estimate the duration of the member to range from 2.31 to 2.61 m.y. This is the fi rst estimate for the duration and age of the Ludlow Member, and it can be used as an important tool for interpreting rates of biotic recovery after the K-T extinction.
Leo J. Hickey - One of the best experts on this subject based on the ideXlab platform.
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Fort Union Formation Fossil Leaves (Paleocene, Williston Basin, North Dakota, USA) Indicate Evolutionary Relationships Between Paleocene and Eocene Plant Species
Bulletin of the Peabody Museum of Natural History, 2014Co-Authors: Daniel J. Peppe, Leo J. HickeyAbstract:Abstract Six fossil leaf species are described from impression fossils collected from the Paleocene Fort Union Formation in the Williston Basin in southwestern North Dakota, USA. They are Meliosma vandaelium sp. nov., Meliosma thriviensis sp. nov., Ternstromites paucimissouriensis sp. nov., Macginitiea nascens sp. nov., Dicotylophyllum horsecreekium sp. nov. and Dicotylophyllum hansonium sp. nov. These species represent some of the elements of the Fort Union Formation that are biostratigraphically important megafloral zone taxa or are species that demonstrate an evolutionary relationship to floras from the Eocene Golden Valley Formation. Some of the species described here suggest that new species endemic to the Williston Basin evolved through the Paleocene and into the Eocene. If the pattern of the origination of endemic daughter species seen in the Williston Basin is consistent across the Western Interior basins of North America, it might have driven up gamma diversity through the Paleogene. This provide...
Aart C Liefbroer - One of the best experts on this subject based on the ideXlab platform.
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Parental Socio-Economic Status and First Union Formation: Can European Variation Be Explained by the Second Demographic Transition Theory?
European Sociological Review, 2017Co-Authors: M. D. Brons, Aart C Liefbroer, Harry B. G. GanzeboomAbstract:Previous research has demonstrated that parental socio-economic status (SES) is an important determinant of the timing of entry into a first co-residential Union. Whilst the majority of existing studies found that young adults from high-SES families delay their first Union compared with those from lower-SES backgrounds, all these studies were conducted within a single country. This study examines the link between parental SES and the timing and type of first Union for 25 European countries participating in the European Social Survey Round 3 (2006/2007). Results from two-step meta-analytical models indicate that in almost all countries young adults from advantaged backgrounds delay their entry into a first Union. This delaying effect of parental SES is stronger if young adults marry directly than if they enter their first Union via unmarried cohabitation. The impact of parental SES is only partly mediated by an individual's own education. The strength of the link between parental SES and Union Formation varies between countries: the delaying impact of parental SES is weakest in those Northern and Western European countries that are most advanced in the Second Demographic Transition. However, after controlling for individual education, the cross-national variation in the link between parental SES and Union Formation disappears.
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The Influence of Parental Education on Timing and Type of Union Formation: Changes Over the Life Course and Over Time in the Netherlands
Demography, 2016Co-Authors: Jarl E. Mooyaart, Aart C LiefbroerAbstract:Family background shapes young adults’ decisions in their transition to adulthood, and the outcomes of these decisions lay the foundation for their subsequent life course. This study examines the influence of parental education on their children’s Union Formation. We examine the timing of entry into a first Union (a married or a cohabiting Union), the choice between marriage and cohabitation, and the timing of first marriage. Data from eight nationally representative surveys conducted in the Netherlands are pooled ( N = 39,777), with respondents being born between 1930 and 1990, to examine not only the effect of parental education on Union Formation but also whether this effect changes over birth cohorts, periods, and the life course, and varies by gender. Results from discrete-time hazard analyses show little change in the effect of parental education across cohorts and periods but strong life-course effects. Gender differences in the effect of parental education are relatively small.
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the influence of criminal offending on Union Formation and Union dissolution for disadvantaged individuals
Advances in Life Course Research, 2016Co-Authors: Mioara Zoutewelleterovan, Victor Van Der Geest, Aart C Liefbroer, Catrien C.j.h. BijleveldAbstract:Using a sample of 248 males and females from The Netherlands, we study the effect of criminal offending on Union Formation and Union dissolution. Criminal and relational careers of high-risk respondents are analyzed using a long observation period (age 12 to age 36). Findings for men support the hypothesis that past criminal offending reduces the likelihood of being involved in a romantic relationship. Furthermore, male's past violent offending increases the probability of being single. Analysis of Union dissolution for males showed that only recent violent offending is associated with the termination of a romantic relationship. Similar to our findings for men, findings for females show that the likelihood of being involved in a romantic relationship is negatively associated with past criminal offending. Moreover, it is an extended cumulative history of property offenses that significantly increases the likelihood of being single throughout the observation period. For women, recent offending significantly increases the probability of separation/divorce.
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Parental Influence On Union Formation Preferences Among Turkish, Moroccan, and Dutch Adolescents in the Netherlands
Journal of Cross-Cultural Psychology, 2007Co-Authors: H.a.g. De Valk, Aart C LiefbroerAbstract:This study first examines Union Formation preferences of Turkish, Moroccan, and Dutch adolescents. Second, the study shows how and to what extent parents are of influence on these preferences. Hypotheses are derived from cross-cultural psychology and theories on intergenerational transmission. Self-reported data of approximately 19,000 Dutch, 460 Turkish, and 400 Moroccan adolescents 11 to 23 years of age are used to test the hypotheses. Youth with a Turkish and Moroccan background, particularly those with a strong ethnic identification, more often prefer marriage than Dutch youth. Unmarried cohabitation (before marriage) is most popular among Dutch adolescents, but substantial proportions of immigrant youth also prefer this type of relationship. In addition, both parental characteristics and characteristics of the parent—child relationship are of major influence for adolescents' Union Formation preferences. The process of intergenerational transmission is found to be largely comparable among all groups.
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The Impact of Rational Considerations and Perceived Opinions on Young Adults' Union Formation Intentions
Journal of Family Issues, 1993Co-Authors: Aart C Liefbroer, Jenny De Jong GierveldAbstract:This article examines the extent to which the plans of young adults concerning the choice between cohabitation and marriage are influenced by a rational evaluation of the differences between marriage and cohabitation and by the perceived opinions of significant others, and the extent to which these evaluations mediate the effects of young adults' family backgrounds and current social positions. Among a representative sample of young adults in the Netherlands, it is found that evaluations and perceived opinions are quite strong predictors of Union Formation intentions. However, perceived opinions of significant others are better predictors than evaluations of the inherent properties of cohabitation and marriage. Furthermore, the effects of family background and social status variables on Union Formation intentions are almost completely mediated by these subjective evaluations. The implications for the discussion of whether Union Formation choices are rational decisions or based on cultural scripts are discussed.
Jane Menken - One of the best experts on this subject based on the ideXlab platform.
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Premarital Births and Union Formation in Rural South Africa.
International perspectives on sexual and reproductive health, 2016Co-Authors: Christie Sennott, Georges Reniers, F. Xavier Gómez-olivé, Jane MenkenAbstract:In rural South Africa, women often delay Union Formation until they are in their late 20s, though premarital first births are common. Longitudinal data from the Agincourt Health and Socio-Demographic Surveillance System in rural South Africa were used to examine the relationship between premarital birth and Union entry among 55,158 nonmigrant women aged 10-35 who took part in at least one annual census from 1993 to 2012. Discrete-time event history models were used to determine whether the likelihood of Union Formation differed between women who had had a premarital first birth and those who had not. Associations between single motherhood and Union type (marriages or nonmarital partnerships) were identified using logistic regression. Forty-five percent of women had had a premarital first birth and 25% had entered a first Union. Women who had had a premarital first birth were less likely than other women to have entered a first Union (odds ratio, 0.6). Women who had had a premarital birth in the past year were more likely than those without a premarital birth to have entered a Union (1.5), but women had reduced odds of Union Formation if they had had a birth 1-2 years earlier (0.9) or at least five years earlier (0.8). Unions formed within two years of a premarital birth had an elevated likelihood of being nonmarital partnerships (1.2-1.4). Single motherhood is common in the Agincourt HDSS, and women with a premarital first birth face challenges in establishing committed Unions with partners.
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premarital births and Union Formation in rural south africa
International Perspectives on Sexual and Reproductive Health, 2016Co-Authors: Christie Sennott, Georges Reniers, Xavier F Gomezolive, Jane MenkenAbstract:CONTEXT: In rural South Africa, women often delay Union Formation until they are in their late 20s, though premarital first births are common. METHODS: Longitudinal data from the Agincourt Health and Socio-Demographic Surveillance System in rural South Africa were used to examine the relationship between premarital birth and Union entry among 55,158 nonmigrant women aged 10–35 who took part in at least one annual census from 1993 to 2012. Discrete-time event history models were used to determine whether the likelihood of Union Formation differed between women who had had a premarital first birth and those who had not. Associations between single motherhood and Union type (marriages or nonmarital partnerships) were identified using logistic regression. RESULTS: Forty-five percent of women had had a premarital first birth and 25% had entered a first Union. Women who had had a premarital first birth were less likely than other women to have entered a first Union (odds ratio, 0.6). Women who had had a premarital birth in the past year were more likely than those without a premarital birth to have entered a Union (1.5), but women had reduced odds of Union Formation if they had had a birth 1–2 years earlier (0.9) or at least five years earlier (0.8). Unions formed within two years of a premarital birth had an elevated likelihood of being nonmarital partnerships (1.2–1.4). CONCLUSIONS: Single motherhood is common in the Agincourt HDSS, and women with a premarital first birth face challenges in establishing committed Unions with partners.
Sarah J. Cookson - One of the best experts on this subject based on the ideXlab platform.
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Metabolite profiling during graft Union Formation reveals the reprogramming of primary metabolism and the induction of stilbene synthesis at the graft interface in grapevine.
BMC plant biology, 2019Co-Authors: Duyên Prodhomme, Céline Franc, Ghislaine Hilbert, Gilles De Revel, Tristan Richard, Nathalie Ollat, Josep Valls Fonayet, Cyril Hévin, Sarah J. CooksonAbstract:Grafting with rootstocks is essential for the culture of many perennial fruit crops and is increasing being used in the production of annual fruits and vegetables. Our previous work based on microarrays showed that transcripts encoding enzymes of both primary and secondary metabolism were differentially expressed during graft Union Formation in both homo-grafts (a genotype grafted with itself) and hetero-grafts (two different genotypes grafted together). The aim of this study was to profile primary and secondary metabolites, and quantify the activity of phenylalanine ammonia lyase (PAL) and neutral invertase (NI) in the scion and rootstock tissues and the graft interface of homo and hetero-grafts of grapevine 1 month after grafting. Table-top grafting was done on over-wintering stems (canes) of grapevine and the graft interface tissues (containing some woody stem tissues and callus) were compared to the surrounding rootstock and scion tissues. The objective was to identify compounds involved in graft Union Formation and hetero-grafting responses. A total of 54 compounds from primary and secondary metabolism (19 amino acids, five primary and 30 secondary compounds metabolites) and the activity of two enzymes were measured. The graft interface was associated with an increase in the accumulation of the branched-chain amino acids, basic amino acids, certain stilbene compounds and higher PAL and NI activity in comparison to the surrounding woody stem tissues. Some amino acids and stilbenes were identified as being accumulated differently between the graft interfaces of the scion/rootstock combinations in a manner which was unrelated to their concentrations in the surrounding woody stem tissues. This study revealed the modification of primary metabolism to support callus cell Formation and the stimulation of stilbene synthesis at the graft interface, and how these processes are modified by hetero-grafting. Knowledge of the metabolites and/or enzymes required for successful graft Union Formation offer us the potential to identify markers that could be used by nurseries and researchers for selection and breeding purposes.
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Metabolite profiling during graft Union Formation reveals the reprogramming of primary metabolism and the induction of stilbene synthesis at the graft interface in grapevine
BMC Plant Biology, 2019Co-Authors: Duyên Prodhomme, Josep Valls Fonayet, Céline Franc, Ghislaine Hilbert, Gilles De Revel, Tristan Richard, Nathalie Ollat, Sarah J. CooksonAbstract:BACKGROUND: Grafting with rootstocks is essential for the culture of many perennial fruit crops and is increasing being used in the production of annual fruits and vegetables. Our previous work based on microarrays showed that transcripts encoding enzymes of both primary and secondary metabolism were differentially expressed during graft Union Formation in both homo-grafts (a genotype grafted with itself) and hetero-grafts (two different genotypes grafted together). The aim of this study was to profile primary and secondary metabolites, and quantify the activity of phenylalanine ammonia lyase (PAL) and neutral invertase (NI) in the scion and rootstock tissues and the graft interface of homo and hetero-grafts of grapevine 1 month after grafting. Table-top grafting was done on over-wintering stems (canes) of grapevine and the graft interface tissues (containing some woody stem tissues and callus) were compared to the surrounding rootstock and scion tissues. The objective was to identify compounds involved in graft Union Formation and hetero-grafting responses. RESULTS: A total of 54 compounds from primary and secondary metabolism (19 amino acids, five primary and 30 secondary compounds metabolites) and the activity of two enzymes were measured. The graft interface was associated with an increase in the accumulation of the branched-chain amino acids, basic amino acids, certain stilbene compounds and higher PAL and NI activity in comparison to the surrounding woody stem tissues. Some amino acids and stilbenes were identified as being accumulated differently between the graft interfaces of the scion/rootstock combinations in a manner which was unrelated to their concentrations in the surrounding woody stem tissues. CONCLUSIONS: This study revealed the modification of primary metabolism to support callus cell Formation and the stimulation of stilbene synthesis at the graft interface, and how these processes are modified by hetero-grafting. Knowledge of the metabolites and/or enzymes required for successful graft Union Formation offer us the potential to identify markers that could be used by nurseries and researchers for selection and breeding purposes.
