Search

The ALPHA collaboration has successfully demonstrated the production and the confinement of cold antihydrogen, $\overline{\mathrm{H}}$. An analysis of trapping data allowed a stringent limit to be placed on the electric charge of the simplest antiatom. Charge neutrality of matter is known to a very high precision, hence a neutrality limit of $\overline{\mathrm{H}}$ provides a test of CPT invariance. The experimental technique is based on the measurement of the deflection of putatively charged $\overline{\mathrm{H}}$ in an electric field. The tendency for trapped $\overline{\mathrm{H}}$ atoms to be displaced by electrostatic fields is measured and compared to the results of a detailed simulation of $\overline{\mathrm{H}}$ dynamics in the trap. An extensive survey of the systematic errors is performed, with particular attention to those due to the silicon vertex detector, which is the device used to determine the $\overline{\mathrm{H}}$ annihilation position. The limit obtained on the charge of the $\overline{\mathrm{H}}$ atom is \mbox{$ Q = (-1.3\pm1.8\pm0.4)\times10^{-8}$}, representing the first precision measurement with $\overline{\mathrm{H}}$., Comment: 5 pages, 3 figures

Although the ultimate purpose of a seed is the successful establishment of the next generation, seed development involves more than embryo growth. In angiosperms, seed development requires the intimate coordination of three distinct entities — maternal tissue and two offspring, embryo and embryo-nourishing endosperm. Although seeds are cornerstones of many terrestrial ecosystems and human diets, we are only beginning to understand the interactions among seed tissues and the molecular processes and genes that determine them. Recent studies of gene expression and function in distantly related angiosperms, combined with over 100 years of embryological research, have repeatedly highlighted the endosperm associated with maternal-filial boundaries as a central point in seed developmental dynamics. In this review, we highlight evidence that links this zone with nutritional dynamics, developmental signaling, and imprinted gene expression. We suggest that the underappreciated diversity of this specialized endosperm across angiosperms deserves further study from developmental, molecular, and genetic perspectives.

A dense plasma focus (DPF) is a compact coaxial plasma gun, which completes its discharge as a Z-pinch, producing short (11 neutrons/pulse at 3.3 MA peak current, and higher-current commissioning is under way. Like most DPFs, MJOLNIR exhibits variable yields in some configurations. We present evidence of the role of parasitic current paths within the gun in stochastically influencing the yield. First through “conditioning shots,” where new hardware has been introduced, we show that increased run-down and run-in speeds correlate with higher yields. These observations are consistent with current being delivered to the electrodes but not to the main plasma sheath, degrading the implosion-driving force. Once nominal conditions are established, we correlate low-performing discharges with smaller current dip and associated voltage spike for a fixed machine configuration. A snow-plow model is able to recreate small-magnitude current dips through the introduction of a parasitic current path, and particle-in-cell simulations establish how parasitic current paths lower the ion beam energy available to produce neutrons. Finally, we observe an increased likelihood of shots with low yield and smaller current dip with increasing fill pressure.

The first record of gene expression during seed development within the Nymphaeales provides evidence for a variety of biological processes, including dynamic epigenetic patterning during sexual reproduction in the water lily Nymphaea thermarum. Studies of gene expression during seed development have been performed for a growing collection of species from a phylogenetically broad sampling of flowering plants (angiosperms). However, angiosperm lineages whose origins predate the divergence of monocots and eudicots have been largely overlooked. In order to provide a new resource for understanding the early evolution of seed development in flowering plants, we sequenced transcriptomes of whole ovules and seeds from three key stages of reproductive development in the waterlily Nymphaea thermarum, an experimentally tractable member of the Nymphaeales. We first explore patterns of gene expression, beginning with mature ovules and continuing through fertilization into early- and mid-stages of seed development. We find patterns of gene expression that corroborate histological/morphological observations of seed development in this species, such as expression of genes involved in starch synthesis and transcription factors that have been associated with embryo and endosperm development in other species. We also find evidence for processes that were previously not known to be occurring during seed development in this species, such as epigenetic modification. We then examine the expression of genes associated with patterning DNA and histone methylation-processes that are essential for seed development in distantly related and structurally diverse monocots and eudicots. Around 89% of transcripts putatively homologous to DNA and histone methylation modifiers are expressed during seed development in N. thermarum, including homologs of genes known to pattern imprinting-related epigenetic modifications. Our results suggest that dynamic epigenetic patterning is a deeply conserved aspect of angiosperm seed development.

Studies of gene expression during seed development have been performed for a growing collection of species from a phylogenetically broad sampling of flowering plants (angiosperms). However, attention has mostly been focused on crop species or a small number of ‘model’ systems. Information on gene expression during seed development is minimal for those angiosperm lineages whose origins predate the divergence of monocots and eudicots. In order to provide a new perspective on the early evolution of seed development in flowering plants, we sequenced transcriptomes of whole ovules and seeds from three key stages of reproductive development in the waterlily Nymphaea thermarum, an experimentally-tractable member of the Nymphaeales. We first explore general patterns of gene expression, beginning with mature ovules and continuing through fertilization into early- and mid-seed development. We then examine the expression of genes associated with DNA and histone methylation – processes known to be essential for development in distantly-related and structurally-divergent monocots and eudicots. Around 60% of transcripts putatively homologous to DNA and histone methylation modifiers are differentially expressed during seed development in N. thermarum, suggesting that the importance of dynamic epigenetic patterning during seed development dates to the earliest phases of angiosperm evolution. However, genes involved in establishing, maintaining, and removing methylation marks associated with genetic imprinting show a mix of conserved and unique expression patterns between N. thermarum and other flowering plants. Our data suggests that the regulation of imprinting has likely changed throughout angiosperm evolution, and furthermore identifies genes that merit further characterization in any angiosperm system.

Seeds are a key life cycle stage for many plants. Seeds are also the basis of agriculture and the primary source of calories consumed by humans1. Here, we employ single-nucleus RNA-sequencing to generate a transcriptional atlas of developing Arabidopsis thaliana seeds, with a focus on endosperm. Endosperm, the primary site of gene imprinting in flowering plants, mediates the relationship between the maternal parent and the embryo2. We identify transcriptionally uncharacterized nuclei types in the chalazal endosperm, which interfaces with maternal tissue for nutrient unloading3,4. We demonstrate that the extent of parental bias of maternally expressed imprinted genes varies with cell-cycle phase, and that imprinting of paternally expressed imprinted genes is strongest in chalazal endosperm. Thus, imprinting is spatially and temporally heterogeneous. Increased paternal expression in the chalazal region suggests that parental conflict, which is proposed to drive imprinting evolution, is fiercest at the boundary between filial and maternal tissues. This study generated a transcriptional atlas of developing Arabidopsis seeds with single-nucleus RNA-sequencing, reporting transcriptionally uncharacterized nuclei types in the chalazal endosperm and spatially and temporally heterogenous imprinting in the seeds.

Seeds are the basis of agriculture, yet their full transcriptional complexity has remained unknown. Here, we employ single-nucleus RNA-sequencing to characterize developing Arabidopsis thaliana seeds, with a focus on endosperm. Endosperm, the site of gene imprinting in plants, mediates the relationship between the maternal parent and embryo. We identify new cell types in the chalazal endosperm region, which interfaces with maternal tissue for nutrient unloading. We further demonstrate that the extent of parental bias of maternally expressed imprinted genes varies with cell cycle phase, and that imprinting of paternally expressed imprinted genes is strongest in chalazal endosperm. These data indicate imprinting in endosperm is heterogeneous and suggest that parental conflict, which is proposed to drive the evolution of imprinting, is fiercest at the boundary between filial and maternal tissues.

For more than 225 million y, all seed plants were woody trees, shrubs, or vines. Shortly after the origin of angiosperms ∼140 million y ago (MYA), the Nymphaeales (water lilies) became one of the first lineages to deviate from their ancestral, woody habit by losing the vascular cambium, the meristematic population of cells that produces secondary xylem (wood) and phloem. Many of the genes and gene families that regulate differentiation of secondary tissues also regulate the differentiation of primary xylem and phloem, which are produced by apical meristems and retained in nearly all seed plants. Here, we sequenced and assembled a draft genome of the water lily

The temperature of a nonneutral plasma confined in a Penning-Malmberg trap can be determined by slowly lowering one side of the trap's electrostatic axial confinement barrier; the temperature is inferred from the rate at which particles escape the trap as a function of the barrier height. In many experiments, the escaping particles are directed toward a microchannel plate, and the resulting amplified charge is collected on a phosphor screen. The screen is used for imaging the plasma but can also be used as a Faraday cup (FC) for a temperature measurement. The sensitivity limit is then set by microphonic noise enhanced by the screen's high-voltage bias. Alternately, a silicon photomultiplier (SiPM) can be employed to measure the charge via the light emitted from the phosphor screen. This decouples the signal from the microphonic noise and allows the temperature of colder and smaller plasmas to be measured than could be measured previously; this paper focuses on the advantages of a SiPM over a FC.

Chiara Lubich possessed “an almost prophetic capacity to intuit and actualise beforehand ‘the thought of the Pope’.” These significant words of Benedict XVI appear in a letter, read out by the Secretary of State, Cardinal Tarcisio Bertone, at Chiara Lubich’s funeral Mass in 2008, following the Pope’s mention of her uninterrupted bond with his predecessors from John XXIII to John Paul II. Saint John Paul II, born in the same year as Chiara and whose papacy was the longest to run in parallel with her action as Founder and President of the Focolare Movement, would surely have agreed on several counts. In his 1984 visit to the International Centre of the Focolare in Rocca di Papa, he had put his finger on one example recognising “the radicalism of love of Chiara, of the Focolarini,” – a “Gospel radicalism of love” – as an answer to what had long been his concern for a hate-dominated world. He saw it as a source of renewal in the direction of the vision of Church outlined in the Vatican Constitutions Lumen gentium and Gaudium et spes. [excerpt], peer-reviewed

For more than 225 million years, all seed plants were woody trees, shrubs, or vines (1–4). Shortly after the origin of angiosperms ~135 million years ago (MYA) (5), the Nymphaeales (water lilies) became one of the first lineages to deviate from their ancestral, woody habit by losing the vascular cambium (6), the meristematic population of cells that produces secondary xylem (wood) and phloem. Many of the genes and gene families that regulate differentiation of secondary tissues also regulate the differentiation of primary xylem and phloem (7–9), which are produced by apical meristems and retained in nearly all seed plants. Here we sequence and assemble a draft genome of the water lily Nymphaea thermarum, an emerging system for the study of early flowering plant evolution, and compare it to genomes from other cambium-bearing and cambium-less lineages (like monocots and Nelumbo). This reveals lineage-specific patterns of gene loss and divergence. Nymphaea is characterized by a significant contraction of the HD-ZIP III transcription factors, specifically loss of REVOLUTA, which influences cambial activity in other angiosperms. We also find the Nymphaea and monocot copies of cambium-associated CLE signaling peptides display unique substitutions at otherwise highly conserved amino acids. Nelumbo displays no obvious divergence in cambium-associated genes. The divergent genomic signatures of convergent vascular cambium loss reveals that even pleiotropic genes can exhibit unique divergence patterns in association with independent trait loss events. Our results shed light on the evolution of herbaceousness – one of the key biological innovations associated with the earliest phases of angiosperm evolution.Significance StatementFor ~225 million years, all seed plants were woody trees, shrubs, or vines. Shortly after the origin of flowering plants ~135 million years ago, Nymphaeales (water lilies) became one of the first seed plant lineages to become herbaceous through loss of the meristematic cell population known as the vascular cambium. We sequence and assemble the draft genome of the water lily Nymphaea thermarum, and compare it to genomes of other plants that have retained or lost the vascular cambium. By using both genome-wide and candidate-gene analysis, we find lineage-specific patterns of gene loss and divergence associated with cambium loss. Our reveal divergent genomic signatures of convergent trait loss in a system characterized by complex gene-trait relationships.

* Doutora em Educação pela Universidade Federal de Sergipe com estágio de doutorado sanduíche no Istituto Universitario Sophia, Itália (2012). Professora das Faculdades Integradas de Sergipe - FISE e da Faculdade Jardins (2014). Membro da Sociedade Brasileira de História da Educação.** Doutora em Teologia Dogmática pela Pontificia Università Lateranense, Roma. Professora do Istituto UniversitarioUSophia. Coordenadora do Programa de Doutorado em Pesquisa Transdisciplinar "Fondamenti e Prospettive di una Cultura dell'Unità ", Istituto Universitario Sophia."Escrever-te-ei sem demora"! O epistolario de Chiara Lubich: estratégias e práticasResumo: Este artigo ressalta o debate acerca dos usos das correspondências como fonte para os estudos de História da Educação e, sobretudo, da História da Educação religiosa católica. Chiara Lubich, professora italiana, adotou as cartas como um recurso de formação capaz de chegar a pessoas e lugares onde não poderia estar fisicamente e, ao longo de sua vida, criou uma abordagem educativa por meio epistolar que, pela notoriedade em âmbito religioso e social, pode ser considerada uma perspectiva diferenciada de pedagogia católica. O estudo visa identificar por meio da análise de um de seus epistolários, o enfoque pedagógico contido em seus escritos. A reflexão apresenta como subsídios teóricos os conceitos de materialidade de Roger Chartier; carisma, campo religioso e relações simbólicas de Pierre Bourdieu, além de estratégia e tática de Michel de Certeau.Palavras-chave: Correspondências. Chiara Lubich. Pedagogia. História da Educação."I will write immediately"! The Chiara Lubich's epitolary: strategies and practicesAbstract: This article emphasizes the debate about the use of written correspondence as a source for the study of the History of Education and especially the history of Catholic religious education. Chiara Lubich, an Italian Catholic school teacher who, used letters as a privileged way to keep in touch with the people. She took letters as a resource able to reach people and places where she could not be physically present and, created an educational approach epistolary, who can be considered as a different perspective in Catholic pedagogy. The research aims to identify and analyze how Chiara's teaching activity through epistolary medium was configured and, specifically, what formative approach is contained in these writings. The theoretical foundation of the research is based on the concepts of materiality, by Roger Chartier; charisma, religious field and symbolic relations of Pierre Bourdieu; in addition, Michel de Certeau's strategy and tactic were used.Keywords: Chiara Lubich. Correspondence. History of Education. Pedagogy."Ti scriverò presto"! Lo epistolà rio di Chiara Lubich: strategia e praticheSommario:Obiettivo di questo lavoro è l'analisi della valenza formativa della scrittura epistolare nella storia dell'educazione, soprattutto nella storia dell'educazione cattolica. Chiara Lubich, un'insegnante italiana, ha utilizzato la "corrispondenza" come "metodo" di formazione e "mezzo" privilegiato per raggiungere e rimanere in contatto con le persone anche in luoghi in cui non poteva essere fisicamente presente. L'epistolario di Chiara, anche per la sua notorietà in ambito religioso e sociale, può essere considerato come un particolare approccio educativo nell'ambito della pedagogia Cattolica. Lo studio si propone di individuare attraverso l'analisi di uno dei suoi epistolari, l'approccio pedagogico contenute nei suoi scritti. La riflessione presenta come supporto teorico i concetti di materialità di Roger Chartier; carisma, campo religioso e relazioni simboliche di Pierre Bourdieu; strategia e tattica di Michel de Certeau.Parole chiave: Chiara Lubich. Pedagogia. Scrittura epistolare. Storia dell Educazione.Data de registro: 17/11/2015Data de aceite: 18/01/2016Referências:ANNUARIO della R. Scuola Complementare "N. E p.Bronzetti" di Trento. Per l'anno scolastico 1927-1928. Anno VI dell'era fascista. Trento: Tipografia - Libreria Ed. G. B. Monauni, 1928.ANNUARIO della R. Scuola di avviamento al lavoro "N. E p.Bronzetti" classe I e della R. Scuola Complementare classe II e III di Trento. Per l'anno scolastico 1929-1930. Anno VIII dell'era fascista. Trento: Tipografi a artiglianelli, 1930.AGUIAR, Thiago Borges. Jan Hus: As cartas de um educador e seu legado imortal. 305f. 2010. Tese (Doutorado em Educação) - Faculdade de Educação da Universidade de São Paulo, Universidade de São Paulo, São Paulo, 2010.ALMEIDA NETO, Dionísio de. Pelo império da virtude - formação, saberes e práticas de Dom Domingos Quirino de Souza (1813-1863). Aracaju: Gráfica e Editora Triunfo Ltda, 2007.ANDRADE JUNIOR, Péricles Morais de. Sob o olhar diligente do pastor: a Igreja Católica em Sergipe (1831-1926). 2000. Dissertação (Mestrado em Educação) - Faculdade de Educação, Universidade Federal de Sergipe, São Cristóvão, 2000.BIBLIA SAGRADA. Tradução: Centro Bíblico Católico. 31ed. São Paulo: Ave Maria, 1981.BOLONHA, Hugo de. Rationes dictandi. In: TIN, Emerson (Org.). A arte de escrever cartas: Anônimo de Bolonha, Erasmo de Rotterdam, Justo Lípsio. Campinas: UNICAMP, 2005, p. 81-109.BOURDIEU, Pierre. A economia das trocas linguísticas. São Paulo: USP, 2008.______. Gênese e estrutura do campo religioso. In: ______. A economia das trocas simbólicas. 6.ed. São Paulo: Perspectiva, 2005, p. 27-78.______. Algumas propriedades dos campos. In: ______. Questões de Sociologia. São Paulo: Marco Zero, 1980.______. Coisas ditas. São Paulo: Brasiliense, 1990.______. O poder simbólico. Lisboa: DIFEL; Rio de Janeiro: Editora Bertrand Brasil, 1989.BURKE, Peter. O que é história cultural? Rio de Janeiro: Jorge Zahar, 2005.CAMARGO, Maria Rosa Rodrigues Martins de. Cartas e escrita. 2000. 147f. Tese (Doutorado em Educação) - Faculdade de Educação, Universidade Estadual de Campinas, Campinas 2000a.CAMARGO, Maria Rosa Rodrigues Martins de. Cartas adolescentes. Uma leitura e modos de ser... In: MIGNOT, Ana Chrystina Venâncio; BASTOS, Maria Helena Camara; CUNHA, Maria Teresa Santos (Org.). Refúgios do eu: educação, história e escrita autobiográfi ca. Florianópolis: Mulheres, 2000b, p. 203-228.CAMBI, Franco. História da pedagogia. São Paulo: UNESP, 1999.CARELLA, Vitantonio. Silvia/Chiara Lubich le sue origini e la sua formazione (1920-1943). 2012. Monografi a (Bacharelado em Teologia) - Instituto Teológico de Trento, Trento, 2012.CERTEAU, Michel de. A invenção do cotidiano: 1. artes de fazer. Petrópolis: Vozes, 1994.CHARTIER, Roger. Os desafi os da escrita. São Paulo: UNESP, 2002b.______. A beira da falésia: a história entre incertezas e inquietude. Porto Alegre: UFRGS, 2002a.______. (Dir). La correspondance. Les usages de la lettre au XIX siècle. Paris: Fayard, 1991.COMENIUS. Didática magna. São Paulo: Martins Fontes, 2002.CUNHA, Maria Teresa Santos. Os dizeres das regras: um estudo sobre Manuais de civilidade e etiqueta. In: CONGRESSO BRASILEIRO DE HISTÓRIA DA EDUCAÇÃO, 3., 2004, Curitiba, Anais... Curitiba, 2004.FOLGHERAITER, Piera. La mia collega Silvia. Rivista Città Nuova. Roma, n. 5, p. 46-48, Mar. 2010.FOLONARI, Giulia Eli. Lo Spartito scritto in cielo: cinquant'anni com Chiara Lubich. Roma: Città Nuova, 2012a.______. Depoimento durante o lançamento do livro: Lo spartito scritto in cielo. Loppiano, 30 de outubro de 2012c.FOUCAULT, Michel. A escrita de si. In: ______. O que é um autor? Lisboa: Passagens. 1992, p. 129-160.FREITAS, Marcos Cezar. Por quem os sinos dobram? As cartas pastorais e a contribuição da História da Educação à história das mentalidades. In: BASTOS, Maria Helena Câmara; CUNHA, Maria Teresa Santos; MIGNOT, Ana Chrystina Venâncio (Org.). Destinos das letras: história, educação e escrita epistolar. Passo Fundo: UPF, 2002, p. 57-73.GIORDANI, Igino. Storia del nascente Movimento dei Focolari. In: LUBICH, Chiara; GIORDANI, Igino. Erano tempi di Guerra… agli albori dell'ideale dell'unità . 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São Paulo: Cidade Nova, 1988a.______. A vida, uma viagem... São Paulo: Cidade Nova, 1986.______. La vita un viaggio. Roma: Città Nuova, 1984b.LUSTOSA, Oscar de Figueiredo. Os bispos do Brasil e a imprensa. São Paulo: Edições Loyola, 1983.MARCUSCHI, Luiz Antônio. Produção textual, análise de gêneros e compreensão. São Paulo: Parábola Editorial, 2008.MIGNOT, Ana Chrystina Venâncio; GONDRA, José Gonçalves (Org.). Viagens pedagógicas. São Paulo: Cortez, 2007.MIGNOT, Ana Chrystina Venâncio; GONDRA, José Gonçalves (Org.). Papéis guardados. Rio de Janeiro: Rede Sirius, 2003.NASCIMENTO, Jorge Carvalho do. As boas maneiras como virtude cristã: O Compêndio de Civilidade dos padres salesianos. Disponível em: . Acesso em: 14 fev. 2013.NEVES, Luiz Felipe Baêta. Para uma teoria da carta: notas de pesquisa. In: NEVES, Luiz Felipe Baêta. As máscaras da totalidade totalitária: memória e produção sociais. 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Supplementary Information

To examine the association of an automated physician feedback system prompting physician review of early readmissions with a change in overall readmission rates.The University of Utah Internal Medicine Hospitalist Service created an automated system to alert discharging providers to any patient readmitted within 30 days. For any 7-day readmission, the physician was asked to complete a survey to describe the admission and discharge and to identify contributing factors to the readmission. Using the University HealthSystem Consortium database, readmission rates were compared prior to and following this intervention.Following the intervention, 30-day readmission rates significantly decreased from 13.93% to 11.99% (p = 0.0298). The 7-day readmission rates decreased as well but the findings were not statistically significant. The discharging physician deemed 45% of the readmissions preventable or probably preventable.Readmissions are common, costly and potentially preventable. This tool for physician audit and feedback and identification of defects contributing to readmissions was associated with a statistically significant decrease in 30-day readmissions. Further investigation is needed to verify these results and evaluate the best mechanism of application.

Theoretical and empirical studies have long connected the evolutionary innovation of endosperm, a genetically biparental product of a double fertilization process unique to flowering plants (angiosperms), to conflicting parental interests over offspring provisioning. Yet, none of these studies examined interparental conflict in representatives of any of the most ancient angiosperm lineages. We performed reciprocal interploidy crosses in the water lilyNymphaea thermarum, a member of one of the most ancient angiosperm lineages, Nymphaeales. We find that an excess of paternal genomes is associated with an increase in endosperm growth. By contrast, maternal ploidy negatively influences development or growth of all seed components, regardless of paternal genome dosage. Most relevant to the conflict over distribution of maternal resources, however, is that growth of the perisperm (seed storage tissue derived from the maternal sporophyte, found in all Nymphaeales) is unaffected by paternal genome dosage—ensuring maternal control of maternal resources. We conclude that the evolutionary transfer of embryo-nourishing function from a genetically biparental endosperm to a genetically maternal perisperm can be viewed as an effective maternal strategy to recapture control of resource distribution among progeny, and thus that interparental conflict has influenced the evolution of seed development in this ancient angiosperm lineage.

The dense plasma focus (DPF) is a z-pinch device that starts as a coaxial plasma railgun and ends in an implosion phase. DPF's historically were developed as thermonuclear devices. When used with deuterium and tritium gases a DPF can be used to produce neutrons; however, in operation, DPF's often suffered from inconsistent behavior, and the mechanisms driving the neutron production were poorly understood. Using kinetic modeling techniques recently developed at LLNL, we have gained insight into the mechanisms that lead to particle acceleration in the pinch region and can make informed design decisions for optimizing DPF behavior, from sub-kilojoule to mega-joule scale devices. Experimental DPF platforms at LLNL also serve to validate the behaviors seen in simulations and improve device performance with a view towards increased neutron generation, enhanced reproducibility, and decreased size and energy requirements.

Experiments were performed to maximize the neutron yield from a 2 kJ dense plasma focus (DPF) and characterize the amount of copper sputtered from the surface of an anode by varying the diameter of the anodes’ on-axis hollow. The hollow is a void in the copper material along the longitudinal axis of the anode. All the anodes had an outer diameter of 1.2 in. and the diameter of the hollow varied from 0 in. (no hollow) to 1 in. The anodes with a hollow produced a greater number of neutrons per discharge than the anode without a hollow. Over 40 discharges, the hollow anode that yielded the most neutrons (9.1 ±0.4 ×10 6 neutrons per discharge produced with the 0.75 in. hollow) produced >6 times more neutrons than the anode with no hollow. A qualitative observation of the anodes after 130 discharges showed less surface damage on anodes with a larger hollow. Quantitative sputter measurements were performed by characterizing the amount of copper sputtered onto on-axis quartz targets for three newly machined anodes, each with a particular hollow diameter. The quantitative results matched the qualitative observations: the copper sputter was reduced using larger hollows. The largest hollow sputtered 17 ±1.0 nm/sr/discharge of copper, a reduction of 69 % compared to the anode with the most damage.Experiments were performed to maximize the neutron yield from a 2 kJ dense plasma focus (DPF) and characterize the amount of copper sputtered from the surface of an anode by varying the diameter of the anodes’ on-axis hollow. The hollow is a void in the copper material along the longitudinal axis of the anode. All the anodes had an outer diameter of 1.2 in. and the diameter of the hollow varied from 0 in. (no hollow) to 1 in. The anodes with a hollow produced a greater number of neutrons per discharge than the anode without a hollow. Over 40 discharges, the hollow anode that yielded the most neutrons (9.1 ±0.4 ×10 6 neutrons per discharge produced with the 0.75 in. hollow) produced >6 times more neutrons than the anode with no hollow. A qualitative observation of the anodes after 130 discharges showed less surface damage on anodes with a larger hollow. Quantitative sputter measurements were performed by characterizing the amount of copper sputtered onto on-axis quartz targets for three newly machined ano...

We observe that high-Q electromagnetic cavity resonances increase the cyclotron cooling rate of pure electron plasmas held in a Penning-Malmberg trap when the electron cyclotron frequency, controlled by tuning the magnetic field, matches the frequency of standing wave modes in the cavity. For certain modes and trapping configurations, this can increase the cooling rate by factors of ten or more. In this paper, we investigate the variation of the cooling rate and equilibrium plasma temperatures over a wide range of parameters, including the plasma density, plasma position, electron number, and magnetic field., Comment: 5 pages, 5 figures

© 2016 Macmillan Publishers Limited. All rights reserved. Antimatter continues to intrigue physicists because of its apparent absence in the observable Universe. Current theory requires that matter and antimatter appeared in equal quantities after the Big Bang, but the Standard Model of particle physics offers no quantitative explanation for the apparent disappearance of half the Universe. It has recently become possible to study trapped atoms - of antihydrogen to search for possible, as yet unobserved, differences in the physical behaviour of matter and antimatter. Here we consider the charge neutrality of the antihydrogen atom. By applying stochastic acceleration to trapped antihydrogen atoms, we determine an experimental bound on the antihydrogen charge, Qe, of |Q| < 0.71 parts per billion (one standard deviation), in which e is the elementary charge. This bound is a factor of 20 less than that determined from the best previous measurement of the antihydrogen charge. The electrical charge of atoms and molecules of normal matter is known to be no greater than about 10-21e for a diverse range of species including H2, He and SF6. Charge-parity-time symmetry and quantum anomaly cancellation demand that the charge of antihydrogen be similarly small. Thus, our measurement constitutes an improved limit and a test of fundamental aspects of the Standard Model. If we assume charge superposition and use the best measured value of the antiproton charge, then we can place a new limit on the positron charge anomaly (the relative difference between the positron and elementary charge) of about one part per billion (one standard deviation), a 25-fold reduction compared to the current best measurement.

Magnetically trapped antihydrogen atoms at low temperatures were used to test the charge neutrality of this antiatomic system, by precisely placing a limit to its electrical charge. A new method for measuring the gravitational interaction of antimatter was also developed, and prospects for making a precise measurement of this interaction are discussed. Finally, progress towards a precise, direct test of CPT symmetry by laser spectroscopy of antihydrogen is presented.

The ALPHA project is an international collaboration, based at CERN, with the experimental goal of performing precision spectroscopic measurements on antihydrogen. As part of this endeavor, the ALPHA experiment includes a silicon tracking detector. This detector consists of a three-layer array of silicon modules surrounding the antihydrogen trapping region of the ALPHA apparatus. Using this device, the antihydrogen annihilation position can be determined with a spatial resolution of better than 5 mm. Knowledge of the annihilation distribution was a critical component in the recently successful antihydrogen trapping effort. This paper will describe the methods used to reconstruct annihilation events in the ALPHA detector. Particular attention will be given to the description of the background rejection criteria.