Technological Aspects: High Voltage

This paper covers the theory and technological aspects of high-voltage design for ion sources. Electric field strengths are critical to understanding high-voltage breakdown. The equations governing electric fields and the techniques to solve them are discussed. The fundamental physics of high-voltage breakdown and electrical discharges are outlined. Different types of electrical discharges are catalogued and their behaviour in environments ranging from air to vacuum are detailed. The importance of surfaces is discussed. The principles of designing electrodes and insulators are introduced. The use of high-voltage platforms and their relation to system design are discussed. The use of commercially available high-voltage technology such as connectors, feedthroughs and cables are considered. Different power supply technologies and their procurement are briefly outlined. High-voltage safety, electric shocks and system design rules are covered.Comment: 39 pages, contribution to the CAS-CERN Accelerator School: Ion Sources, Senec, Slovakia, 29 May - 8 June 2012, edited by R. Bailey, CERN-2013-00

When equal couples become unequal partners: Couple relationships and intensive parenting culture

Based on longitudinal research with (heterosexual) couples in the UK, this article tracks their experiences of becoming parents for the first time. The suggestion is that new parents are caught in an uncomfortable confluence between competing discourses around ideal relationships and those around ideal parenting. On the one hand, they must be committed to egalitarian ideals about the division of care. On the other, they must be parenting ‘intensively’, in ways which are markedly more demanding for mothers, and which makes paternal involvement more complicated. Drawing on accounts of relationship difficulties, elicited over a five-year period, the article demonstrates the incommensurability of these ideals at physiological, material and ideological levels. As a contribution to the body of work known as parenting culture studies, this article brings, for the first time, an empirical focus to the question of how an ‘intensive’ parenting culture affects couples, rather than just mothers or fathers

A Comparison of the Behaviors in the Beginning Teacher Program with the Behaviors of Effective Teachers

The behaviors of effective teachers compared to the behaviors indicated on the observation instrument of the Beginning Teacher Program were investigated. Effective teaching behaviors were drawn from professional literature. The results indicate that effective teaching includes competence, performance, and continuing teacher education. The teacher\u27s role as a professional rather than a technician was supported in the literature. The results indicate that effective teachers universally practice the effective behaviors listed in the Beginning Teacher Program which are based on scientific knowledge. The recommendation is that more research should be done in teacher effectiveness and evaluation

A phylogenomic perspective on the radiation of ray-finned fishes based upon targeted sequencing of ultraconserved elements

Ray-finned fishes constitute the dominant radiation of vertebrates with over 30,000 species. Although molecular phylogenetics has begun to disentangle major evolutionary relationships within this vast section of the Tree of Life, there is no widely available approach for efficiently collecting phylogenomic data within fishes, leaving much of the enormous potential of massively parallel sequencing technologies for resolving major radiations in ray-finned fishes unrealized. Here, we provide a genomic perspective on longstanding questions regarding the diversification of major groups of ray-finned fishes through targeted enrichment of ultraconserved nuclear DNA elements (UCEs) and their flanking sequence. Our workflow efficiently and economically generates data sets that are orders of magnitude larger than those produced by traditional approaches and is well-suited to working with museum specimens. Analysis of the UCE data set recovers a well-supported phylogeny at both shallow and deep time-scales that supports a monophyletic relationship between Amia and Lepisosteus (Holostei) and reveals elopomorphs and then osteoglossomorphs to be the earliest diverging teleost lineages. Divergence time estimation based upon 14 fossil calibrations reveals that crown teleosts appeared ~270 Ma at the end of the Permian and that elopomorphs, osteoglossomorphs, ostarioclupeomorphs, and euteleosts diverged from one another by 205 Ma during the Triassic. Our approach additionally reveals that sequence capture of UCE regions and their flanking sequence offers enormous potential for resolving phylogenetic relationships within ray-finned fishes

Adult-child relations in neoliberal times: insights from a dialogue across childhood and parenting culture studies

In this introductory article for the special issue ‘Childhood, Parenting Culture and Adult-Child Relations in Global Perspectives’, we provide an overview of our fields of study (childhood studies and parenting culture studies) by placing them in dialogue. We do so as a basis for drawing out themes emerging from the special issue, in order to explore potential synergies and open broader debates. We begin by tracing moves towards more relational approaches in the social sciences indicating their epistemological and methodological implications. Relational thinking provides a basis for countering antagonistic positionings of children and adults, allowing for circulations of childhood and parenting cultures to be interrogated in relation to new and enduring forms of inequity and changing state-family-capital relations. We suggest that this complicates existing conceptualisations of neoliberalisation while drawing attention to the need for further interrogation of the transnational nature of adult-child relations

Target enrichment of ultraconserved elements from arthropods provides a genomic perspective on relationships among Hymenoptera

Gaining a genomic perspective on phylogeny requires the collection of data from many putatively independent loci collected across the genome. Among insects, an increasingly common approach to collecting this class of data involves transcriptome sequencing, because few insects have high-quality genome sequences available; assembling new genomes remains a limiting factor; the transcribed portion of the genome is a reasonable, reduced subset of the genome to target; and the data collected from transcribed portions of the genome are similar in composition to the types of data with which biologists have traditionally worked (e.g., exons). However, molecular techniques requiring RNA as a template are limited to using very high quality source materials, which are often unavailable from a large proportion of biologically important insect samples. Recent research suggests that DNA-based target enrichment of conserved genomic elements offers another path to collecting phylogenomic data across insect taxa, provided that conserved elements are present in and can be collected from insect genomes. Here, we identify a large set (n$=$1510) of ultraconserved elements (UCE) shared among the insect order Hymenoptera. We use in silico analyses to show that these loci accurately reconstruct relationships among genome-enabled Hymenoptera, and we design a set of baits for enriching these loci that researchers can use with DNA templates extracted from a variety of sources. We use our UCE bait set to enrich an average of 721 UCE loci from 30 hymenopteran taxa, and we use these UCE loci to reconstruct phylogenetic relationships spanning very old ($\geq$220 MYA) to very young ($\leq$1 MYA) divergences among hymenopteran lineages. In contrast to a recent study addressing hymenopteran phylogeny using transcriptome data, we found ants to be sister to all remaining aculeate lineages with complete support