1,541 research outputs found

    Characterizing the local vectorial electric field near an atom chip using Rydberg state spectroscopy

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    We use the sensitive response to electric fields of Rydberg atoms to characterize all three vector components of the local electric field close to an atom-chip surface. We measured Stark-Zeeman maps of SS and DD Rydberg states using an elongated cloud of ultracold Rubidium atoms (T2.5T\sim2.5 μ\muK) trapped magnetically 100100 μ\mum from the chip surface. The spectroscopy of SS states yields a calibration for the generated local electric field at the position of the atoms. The values for different components of the field are extracted from the more complex response of DD states to the combined electric and magnetic fields. From the analysis we find residual fields in the two uncompensated directions of 0.0±0.20.0\pm0.2 V/cm and 1.98±0.091.98\pm0.09 V/cm respectively. This method also allows us to extract a value for the relevant field gradient along the long axis of the cloud. The manipulation of electric fields and the magnetic trapping are both done using on-chip wires, making this setup a promising candidate to observe Rydberg-mediated interactions on a chip.Comment: 8 pages, 5 figure

    Stabilization of the perovskite phase in the Y-Bi-O system by using a BaBiO3_{3} buffer layer

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    A topological insulating phase has theoretically been predicted for the thermodynamically unstable perovskite phase of YBiO3_{3}. Here, it is shown that the crystal structure of the Y-Bi-O system can be controlled by using a BaBiO3_{3} buffer layer. The BaBiO3_{3} film overcomes the large lattice mismatch of 12% with the SrTiO3_{3} substrate by forming a rocksalt structure in between the two perovskite structures. Depositing an YBiO3_{3} film directly on a SrTiO3_{3} substrate gives a fluorite structure. However, when the Y-Bi-O system is deposited on top of the buffer layer with the correct crystal phase and comparable lattice constant, a single oriented perovskite structure with the expected lattice constants is observed.Comment: 8 pages, 7 figures + 4 pages supporting informatio

    Neurobehavioral function and low-level exposure to brominated flame retardants in adolescents : a cross-sectional study

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    Background: Animal and in vitro studies demonstrated a neurotoxic potential of brominated flame retardants, a group of chemicals used in many household and commercial products to prevent fire. Although the first reports of detrimental neurobehavioral effects in rodents appeared more than ten years ago, human data are sparse. Methods: As a part of a biomonitoring program for environmental health surveillance in Flanders, Belgium, we assessed the neurobehavioral function with the Neurobehavioral Evaluation System (NES-3), and collected blood samples in a group of high school students. Cross-sectional data on 515 adolescents (13.6-17 years of age) was available for the analysis. Multiple regression models accounting for potential confounders were used to investigate the associations between biomarkers of internal exposure to brominated flame retardants [serum levels of polybrominated diphenyl ether (PBDE) congeners 47, 99, 100, 153, 209, hexabromocyclododecane (HBCD), and tetrabromobisphenol A (TBBPA)] and cognitive performance. In addition, we investigated the association between brominated flame retardants and serum levels of FT3, FT4, and TSH. Results: A two-fold increase of the sum of serum PBDE's was associated with a decrease of the number of taps with the preferred-hand in the Finger Tapping test by 5.31 (95% CI: 0.56 to 10.05, p = 0.029). The effects of the individual PBDE congeners on the motor speed were consistent. Serum levels above the level of quantification were associated with an average decrease of FT3 level by 0.18 pg/mL (95% CI: 0.03 to 0.34, p = 0.020) for PBDE-99 and by 0.15 pg/mL (95% CI: 0.004 to 0.29, p = 0.045) for PBDE-100, compared with concentrations below the level of quantification. PBDE-47 level above the level of quantification was associated with an average increase of TSH levels by 10.1% (95% CI: 0.8% to 20.2%, p = 0.033), compared with concentrations below the level of quantification. We did not observe effects of PBDE's on neurobehavioral domains other than the motor function. HBCD and TBBPA did not show consistent associations with performance in the neurobehavioral tests. Conclusions: This study is one of few studies and so far the largest one investigating the neurobehavioral effects of brominated flame retardants in humans. Consistently with experimental animal data, PBDE exposure was associated with changes in the motor function and the serum levels of the thyroid hormones

    Resort to Mediation in Maori-to-Maori Dispute Resolution: is it the Elixir to Cure all Ills?

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    Discourse surrounding the Treaty of Waitangi has shifted the Treaty's status from a "simple nullity" to the foundational document of this country. A very specific dimension of Treaty discourse, Maori-to-Maori disputes in the context of Treaty claim settlement, is explored – particularly mediation. The author argues that mediation is far from a cure-all, and should not be used indiscriminately in Maori disputes. Two examples are explored. The Allocation of Commercial Fisheries Settlement presented mediation as a mandatory dispute resolution procedure, undermining the process altogether. The Ngati Maniapoto, Ngati Tama and Crown mediation process failed to provide a level playing field for all parties involved, resulting in continuous alienation. The author concludes that dispute resolution is just one facet of the Treaty discourse, and conversations between institutions, experts, and law-makers should continue regarding how to redefine Treaty principles in a way that does not rip people apart.&nbsp

    Responsible chain management: a capability assessment framework

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    In recent years, increased attention has been paid to issues of responsibility across the entire product lifecycle. Responsible behaviour of organizations in the product chain is dependent on the actions of other parties such as suppliers and customers. Only through co-operation and close interaction between the different parties involved is it possible to come to a specified form of responsible chain management. Drawing on stakeholder theory and literature on the resource-based view of the firm, this article presents a framework for assessing the organizational capabilities of responding to claims from internal and external parties. Interpretations of stakeholder interests, integration into business processes, monitoring these processes, and communication with stakeholders are the central processes in this framework. The application of this framework to three cases of responsible chain management illustrates the functioning of the framework as a tool for assessing organizational capabilities

    Endocrine disruptors and abnormalities of pubertal development

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    Onset and development of puberty is regulated by the neuroendocrine system. Population-based studies worldwide have observed secular trends towards earlier puberty development. These changes are apparently caused by environmental factors such as improved socio-economic status, improved health care and nutrition. However, they may also partly result from endocrine-disrupting chemicals in the environment. Epidemiological studies have investigated the relationship between pubertal development and exposure to endocrine-disrupting chemicals (polychlorinated biphenyls, polybrominated biphenyls, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane, phthalate esters, furans and the pesticide endosulfan). Associations with both perinatal and postnatal exposure have been reported. Studies in experimental animals support some of these findings and point to differential endocrine regulatory mechanisms linked to pubertal development acting in the perinatal and the pre-pubertal period. Pubertal development is naturally associated with growth and body composition. There is increasing evidence for a link between prenatal development and pubertal onset. In girls born small for gestational age (SGA), pubertal onset and age at menarche often are advanced, especially if there has been an extensive catch-up growth during the first months of life. In utero growth retardation may have multiple causes including exposure to xenobiotic substances as was suggested for some endocrine-disrupting chemicals. An abnormal perinatal environment of children born SGA may alter the endocrine status and the sensitivity of the receptors for endocrine and metabolic signalling that may have effects on maturation of brain and gonads. However, the causal pathways and the molecular mechanisms that may link the pubertal growth pattern of children born SGA, pubertal development and endocrine-disrupting chemicals need further study

    Reflections on relationships between NGOs and corporations

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    This review essay reflects on relationships between the NGO activism and advocacy movement and corporations. The essay does so through a review of Yaziji and Doh's 2009 book NGOs and Corporations: Conflict and Collaboration. The review essay considers the strengths and weaknesses of the book in relationship to our understanding of NGOs. The essay emphasizes that both NGO and corporate perspectives are important in assessing NGO-corporation relationships

    Validación de subproductos de café como ingredientes alimentarios para una nutrición y salud sostenible

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    Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Física Aplicada. Fecha de lectura: 25-11-2019Esta tesis tiene embargado el acceso al texto completo hasta el 14-11-2021The present study has been funded by the following project: 1. Producción y consumo sostenibles del café: validación de subproductos como ingredientes alimentarios (SUSCOFFEE, AGL2014-57239-R) funded by the Ministry of Economy and Competitiveness. Amaia Iriondo De Hond received financial support with a PhD scholarship funded by the Ministry of Economy and Competitiveness of Spain (BES-2015-072191)
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