627 research outputs found

    What a difference a term makes:the effect of educational attainment on marital outcomes in the UK

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    Abstract In the past, students in England and Wales born within the first 5 monthsof the academic year could leave school one term earlier than those born later inthe year. Focusing on women, those who were required to stay on an extra termmore frequently hold some academic qualification. Using having been required tostay on as an exogenous factor affecting academic attainment, we find that holding alow-level academic qualification has no effect on the probability of being currentlymarried for women aged 25 or above, but increases the probability of the husbandholding some academic qualification and being economically active.33 Halama

    Polymer patterning by laser-induced multi-point initiation of frontal polymerization

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    Frontal polymerization (FP) is an approach for thermosetting plastics at lower energy cost than an autoclave. The potential to generate simultaneous propagation of multiple polymerization fronts has been discussed as an exciting possibility. However, FP initiated at more than two points simultaneously has not been demonstrated. Multi-point initiation could enable both large scale material fabrication and unique pattern generation. Here the authors present laser-patterned photothermal heating as a method for simultaneous initiation of FP at multiple locations in a 2-D sample. Carbon black particles are mixed into liquid resin (dicyclopentadiene) to enhance absorption of light from a Ti:Sapphire laser (800 nm) focused on a sample. The laser is time-shared by rapid steering among initiation points, generating polymerization using up to seven simultaneous points of initiation. This process results in the formation of both symmetric and asymmetric seam patterns resulting from the collision of fronts. The authors also present and validate a theoretical framework for predicting the seam patterns formed by front collisions. This framework allows the design of novel patterns via an inverse solution for determining the initiation points required to form a desired pattern. Future applications of this approach could enable rapid, energy-efficient manufacturing of novel composite-like patterned materials

    New Circumspection of the Genus \u3ci\u3eGamochaeta\u3c/i\u3e (Asteraceae, Gnaphalieae) Inferred From Nuclear and Plastid DNA Sequences

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    Gamochaeta (tribe Gnaphalieae, Asteraceae) is composed of ca. 60 species primarily distributed in tropical and subtropical America. Within the tribe Gnaphalieae, the genus is characterized by capitula arranged in spikes or head-like clusters, few hermaphroditic central florets, truncate style branches with apical sweeping trichomes, pappus bristles connate at the base into a ring falling as a unit, and achenes with globose twin trichomes. Previous molecular phylogenetic studies have suggested the paraphyly of the genus, but have not provided a basis for redefining generic limits due to incomplete taxon sampling. To address this problem, DNA sequences from the plastid (trnL-F) and nuclear (ETS and ITS) genomes were analyzed from a broad taxon sample representing the full range of morphological variation known in the genus. Our results affirm that Gamochaeta is paraphyletic as presently circumscribed. Two clades can be recognized: one clade that includes the majority of the species currently assigned to Gamochaeta and a second clade that includes Gamochaetopsis, Stuckertiella and seven species of Gamochaeta. We present here a new circumscription of Gamochaeta, including two new combinations, Gamochaeta alpina and Gamochaeta peregrina, and the resurrection of Gamochaeta capitata. Our results also show Omalotheca supina, O. norvegica and O. sylvatica, which were placed by some authors in Gamochaeta or in Gnaphalium, form a monophyletic group distantly related to both genera

    Autonomous clustering using rough set theory

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    This paper proposes a clustering technique that minimises the need for subjective human intervention and is based on elements of rough set theory. The proposed algorithm is unified in its approach to clustering and makes use of both local and global data properties to obtain clustering solutions. It handles single-type and mixed attribute data sets with ease and results from three data sets of single and mixed attribute types are used to illustrate the technique and establish its efficiency

    Factors explaining variance in perceived pain in women with fibromyalgia

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    BACKGROUND: We hypothesized that a substantial proportion of the subjectively experienced variance in pain in fibromyalgia patients would be explained by psychological factors alone, but that a combined model, including neuroendocrine and autonomic factors, would give the most parsimonious explanation of variance in pain. METHODS: Psychometric assessment included McGill Pain Questionnaire, General Health Questionnaire, Hospital Anxiety and Depression Rating Scale, Eysenck personality Inventory, Neuroticism and Lie subscales, Toronto Alexithymia Scale, and Multidimensional Health Locus of Control Scale and was performed in 42 female patients with fibromyalgia and 48 female age matched random sample population controls. A subgroup of the original sample (22 fibromyalgia patients and 13 controls) underwent a pharmacological challenge test with buspirone to assess autonomic and adrenocortical reactivity to serotonergic challenge. RESULTS: Although fibromyalgia patients scored high on neuroticism, anxiety, depression and general distress, only a minor part of variance in pain was explained by psychological factors alone. High pain score was associated with high neuroticism, low baseline cortisol level and small drop in systolic blood pressure after buspirone challenge test. This model explained 41.5% of total pain in fibromyalgia patients. In population controls, psychological factors alone were significant predictors for variance in pain. CONCLUSION: Fibromyalgia patients may have reduced reactivity in the central sympathetic system or perturbations in the sympathetic-parasympathetic balance. This study shows that a biopsychosocial model, including psychological factors as well as factors related to perturbations of the autonomic nervous system and hypothalamic-pituitary-adrenal axis, is needed to explain perceived pain in fibromyalgia patients

    Love and Taxes – And Matching Institutions

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    We study a setting with search frictions in the marriage market and with incomplete contracting inside the family. Everyone prefers a partner that has high income and is a perfect emotional match, but compromises must often be struck. A high income earner may abstain from marrying a low-income earner even though they would be a perfect match emotionally, because the highincome earner may dislike the implicit income redistribution implied by the marriage. Redistributive income taxation may ease this problem. Income matching institutions that secure that people largely from the same income groups meet each other can substitute for redistribution, so that optimal redistribution is reduced. We also introduce a divorce option. Redistributive taxation is shown both to further and stabilize marriage.Wenn Menschen mit unterschiedlichem Einkommen heiraten, führt dies zu einer Umverteilung innerhalb der Ehe von der wirtschaftlich stärkeren zur wirtschaftlich schwächeren Person. Zwei Personen, die zufällig aufeinander treffen und aufgrund ähnlicher Interessen und Neigungen gut zueinander passen, werden auch die finanziellen Folgen einer Heirat berücksichtigen. Falls die Person mit hohem Einkommen diese Umverteilung als zu stark empfindet, kommt die Ehe nicht zustande. Die Rente, die z.B. dadurch entsteht, dass das Paar ähnliche Interessen hat oder gemeinsamen Hobbys nachgehen kann, geht in diesem Fall verloren. Progressive Besteuerung führt zu einer Angleichung der Einkommensverteilung und verringert daher die Wahrscheinlichkeit, dass Ehen aufgrund hoher Einkommensunterschiede nicht zustande kommen. Aus wohlfahrtstheoretischer Sicht ist dies ein positiver Aspekt umverteilender Besteuerung, der bisher in der Literatur nicht berücksichtigt wurde. Die optimale Höhe der Besteuerung hängt von den Matching-Institutionen ab, d.h. davon wer wen auf dem Heiratsmarkt trifft. Treffen vorwiegend Personen mit unterschiedlichem Einkommen und ähnlichen Interessen aufeinander, ist der positive Effekt der Besteuerung besonders wirksam. In diesem Fall ist der optimale Steuersatz umso höher, je ähnlicher die Interessen der potentiellen Partner ist. Umgekehrt kann progressive Besteuerung in einer Gesellschaft, in der vorwiegend Personen mit ohnehin ähnlichem Einkommen aufeinandertreffen, kaum etwas bewirken. Daher fällt in diesem Fall der optimale Steuersatz umso geringer aus, je ähnlicher die Einkommen der potentiellen Paare auf dem Heiratsmarkt sind

    Evidence that abscisic acid promotes degradation of SNF1-related protein kinase (SnRK) 1 in wheat and activation of a putative calcium-dependent SnRK2

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    Sucrose nonfermenting-1 (SNF1)-related protein kinases (SnRKs) form a major family of signalling proteins in plants and have been associated with metabolic regulation and stress responses. They comprise three subfamilies: SnRK1, SnRK2, and SnRK3. SnRK1 plays a major role in the regulation of carbon metabolism and energy status, while SnRKs 2 and 3 have been implicated in stress and abscisic acid (ABA)-mediated signalling pathways. The burgeoning and divergence of this family of protein kinases in plants may have occurred to enable cross-talk between metabolic and stress signalling, and ABA-response-element-binding proteins (AREBPs), a family of transcription factors, have been shown to be substrates for members of all three subfamilies. In this study, levels of SnRK1 protein were shown to decline dramatically in wheat roots in response to ABA treatment, although the amount of phosphorylated (active) SnRK1 remained constant. Multiple SnRK2-type protein kinases were detectable in the root extracts and showed differential responses to ABA treatment. They included a 42 kDa protein that appeared to reduce in response to 3 h of ABA treatment but to recover after longer treatment. There was a clear increase in phosphorylation of this SnRK2 in response to the ABA treatment. Fractions containing this 42 kDa SnRK2 were shown to phosphorylate synthetic peptides with amino acid sequences based on those of conserved phosphorylation sites in AREBPs. The activity increased 8-fold with the addition of calcium chloride, indicating that it is calcium-dependent. The activity assigned to the 42 kDa SnRK2 also phosphorylated a heterologously expressed wheat AREBP

    Taxing Education in Ramsey’s Tradition

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    Assuming a two-period model with endogenous choices of labour, education, and saving, it is shown to be second-best efficient to deviate from Ramsey's Rule and to distort qualified labour less than nonqualified labour. The result holds for arbitrary utility and learning functions. Efficient incentives for education and saving are analysed under conditions of second and third best. It is argued that efficient tax policy should care more about incentives for education than for saving

    Education and Optimal Dynamic Taxation

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    We study optimal tax and educational policies in a dynamic private information economy, in which ex-ante heterogeneous individuals make an educational investment early in their life and face a stochastic wage distribution. We characterize labor and education wedges in this setting analytically and numerically, using a calibrated example. We present ways to implement the optimum. In one implementation there is a common labor income tax schedule, and a repayment schedule for government loans given out to agents during education. These repayment plans are contingent on loan size and income and capture the history dependence of the labor wedges. Applying the model to US-data and a binary education decision (graduating from college or not) we characterize optimal labor wedges for individuals without college degree and with college degree. The labor wedge of college graduates as a function of income lies first strictly above their counterparts from high-school, but this reverses at higher incomes. The loan repayment schedule is hump-shaped in income for college graduates

    Characterization of complex networks: A survey of measurements

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    Each complex network (or class of networks) presents specific topological features which characterize its connectivity and highly influence the dynamics of processes executed on the network. The analysis, discrimination, and synthesis of complex networks therefore rely on the use of measurements capable of expressing the most relevant topological features. This article presents a survey of such measurements. It includes general considerations about complex network characterization, a brief review of the principal models, and the presentation of the main existing measurements. Important related issues covered in this work comprise the representation of the evolution of complex networks in terms of trajectories in several measurement spaces, the analysis of the correlations between some of the most traditional measurements, perturbation analysis, as well as the use of multivariate statistics for feature selection and network classification. Depending on the network and the analysis task one has in mind, a specific set of features may be chosen. It is hoped that the present survey will help the proper application and interpretation of measurements.Comment: A working manuscript with 78 pages, 32 figures. Suggestions of measurements for inclusion are welcomed by the author
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