1,824 research outputs found

    Unconventional order-disorder phase transition in improper ferroelectric hexagonal manganites

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    The improper ferroelectricity in YMnO3_3 and other related multiferroic hexagonal manganites are known to cause topologically protected ferroelectric domains that give rise to rich and diverse physical phenomena. The local structure and structural coherence across the ferroelectric transition, however, were previously not well understood. Here we reveal the evolution of the local structure with temperature in YMnO3_3 using neutron total scattering techniques, and interpret them with the help of first-principles calculations. The results show that, at room temperature, the local and average structures are consistent with the established ferroelectric P63cmP6_3cm symmetry. On heating, both local and average structural analyses show striking anomalies from 800\sim 800 K up to the Curie temperature consistent with increasing fluctuations of the order parameter angle. These fluctuations result in an unusual local symmetry lowering into a \textit{continuum of structures} on heating. This local symmetry breaking persists into the high-symmetry non-polar phase, constituting an unconventional type of order-disorder transition.Comment: 10 pages, 5 figure

    Charged domain walls in improper ferroelectric hexagonal manganites and gallates

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    Ferroelectric domain walls are attracting broad attention as atomic-scale switches, diodes and mobile wires for next-generation nanoelectronics. Charged domain walls in improper ferroelectrics are particularly interesting as they offer multifunctional properties and an inherent stability not found in proper ferroelectrics. Here we study the energetics and structure of charged walls in improper ferroelectric YMnO3_3, InMnO3_3 and YGaO3_3 by first principles calculations and phenomenological modeling. Positively and negatively charged walls are asymmetric in terms of local structure and width, reflecting that polarization is not the driving force for domain formation. The wall width scales with the amplitude of the primary structural order parameter and the coupling strength to the polarization. We introduce general rules for how to engineer nn- and pp-type domain wall conductivity based on the domain size, polarization and electronic band gap. This opens the possibility of fine-tuning the local transport properties and design pp-nn-junctions for domain wall-based nano-circuitry.Comment: 10 pages, 6 figures, Supp. Info. available on reques

    Data Quality Objectives Supporting Radiological Air Emissions Monitoring for the PNNL Site

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    This document of Data Quality Objectives (DQOs) was prepared based on the U.S. Environmental Protection Agency (EPA) Guidance on Systematic Planning Using the Data Quality Objectives Process, EPA, QA/G4, 2/2006 (EPA 2006) as well as several other published DQOs. Pacific Northwest National Laboratory (PNNL) is in the process of developing a radiological air monitoring program for the PNNL Site that is distinct from that of the nearby Hanford Site. Radiological emissions at the PNNL Site result from Physical Sciences Facility (PSF) major emissions units. A team was established to determine how the PNNL Site would meet federal regulations and address guidelines developed to monitor and estimate offsite air emissions of radioactive materials. The result is a program that monitors the impact to the public from the PNNL Site

    Department of Energy – Office of Science Pacific Northwest Site Office Environmental Monitoring Plan for the DOE-SC PNNL Site

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    The Pacific Northwest Site Office (PNSO) manages the contract for operations at the U.S. Department of Energy Office of Science (DOE-SC) Pacific Northwest National Laboratory (PNNL) Site in Richland, Washington. Radiological operations at the DOE-SC PNNL Site expanded in 2010 with the completion of facilities at the Physical Sciences Facility. As a result of the expanded radiological work at the site, the Washington State Department of Health (WDOH) has required that offsite environmental surveillance be conducted as part of the PNNL Site Radioactive Air Emissions License. The environmental monitoring and surveillance requirements of various orders, regulations, and guidance documents consider emission levels and subsequent risk of negative human and environmental impacts. This Environmental Monitoring Plan (EMP) describes air surveillance activities at the DOE-SC PNNL Site. The determination of offsite environmental surveillance needs evolved out of a Data Quality Objectives process (Barnett et al. 2010) and Implementation Plan (Snyder et al. 2010). The entire EMP is a compilation of several documents, which include the Main Document (this text), Attachment 1: Sampling and Analysis Plan, Attachment 2: Data Management Plan, and Attachment 3: Dose Assessment Guidance

    Data Quality Objectives Supporting Radiological Air Emissions Monitoring for the PNNL Site

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    Pacific Northwest National Laboratory (PNNL) is in the process of developing a radiological air monitoring program for the PNNL Site that is distinct from that of the nearby Hanford Site. The original DQO (PNNL-19427) considered radiological emissions at the PNNL Site from Physical Sciences Facility (PSF) major emissions units. This first revision considers PNNL Site changes subsequent to the implementation of the original DQO. A team was established to determine how the PNNL Site changes would continue to meet federal regulations and address guidelines developed to monitor air emissions and estimate offsite impacts of radioactive material operations. The result is an updated program to monitor the impact to the public from the PNNL Site. The team used the emission unit operation parameters and local meteorological data as well as information from the PSF Potential-to-Emit documentation and Notices of Construction submitted to the Washington State Department of Health (WDOH). The locations where environmental monitoring stations would most successfully characterize the maximum offsite impacts of PNNL Site emissions from the three PSF buildings with major emission units were determined from these data. Three monitoring station locations were determined during the original revision of this document. This first revision considers expanded Department of Energy operations south of the PNNL Site and relocation of the two offsite, northern monitoring stations to sites near the PNNL Site fenceline. Inclusion of the southern facilities resulted in the proposal for a fourth monitoring station in the southern region. The southern expansion added two minor emission unit facilities and one diffuse emission unit facility. Relocation of the two northern stations was possible due to the use of solar power, rather than the previous limitation of the need for access to AC power, at these more remote locations. Addendum A contains all the changes brought about by the revision 1 considerations. This DQO report also updates the discussion of the Environmental Monitoring Plan for the PNNL Site air samples and how existing Hanford Site monitoring program results could be used. This document of Data Quality Objectives (DQOs) was prepared based on the U.S. Environmental Protection Agency (EPA) Guidance on Systematic Planning Using the Data Quality Objectives Process, EPA, QA/G4, 2/2006 (EPA 2006) as well as several other published DQOs

    Data Quality Objectives Supporting Radiological Air Emissions Monitoring for the Marine Sciences Laboratory, Sequim Site

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    This document of Data Quality Objectives (DQOs) was prepared based on the U.S. Environmental Protection Agency (EPA) Guidance on Systematic Planning Using the Data Quality Objectives Process, EPA, QA/G4, 2/2006 (EPA 2006), as well as several other published DQOs. The intent of this report is to determine the necessary steps required to ensure that radioactive emissions to the air from the Marine Sciences Laboratory (MSL) headquartered at the Pacific Northwest National Laboratory’s Sequim Marine Research Operations (Sequim Site) on Washington State’s Olympic Peninsula are managed in accordance with regulatory requirements and best practices. The Sequim Site was transitioned in October 2012 from private operation under Battelle Memorial Institute to an exclusive use contract with the U.S. Department of Energy, Office of Science, Pacific Northwest Site Office

    Regional Fluid-Attenuated Inversion Recovery (FLAIR) at 7 Tesla correlates with amyloid beta in hippocampus and brainstem of cognitively normal elderly subjects

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    Background: Accumulation of amyloid beta (Aβ) may occur during healthy aging and is a risk factor for Alzheimer Disease (AD). While individual Aβ-accumulation can be measured non-invasively using Pittsburgh Compund-B positron emission tomography (PiB-PET), Fluid-attenuated inversion recovery (FLAIR) is a Magnetic Resonance Imaging (MRI) sequence, capable of indicating heterogeneous age-related brain pathologies associated with tissue-edema. In the current study cognitively normal elderly subjects were investigated for regional correlation of PiB- and FLAIR intensity. Methods: Fourteen healthy elderly subjects without known history of cognitive impairment received 11C-PiB-PET for estimation of regional Aβ-load. In addition, whole brain T1-MPRAGE and FLAIR-MRI sequences were acquired at high field strength of 7 Tesla (7T). Volume-normalized intensities of brain regions were assessed by applying an automated subcortical segmentation algorithm for spatial definition of brain structures. Statistical dependence between FLAIR- and PiB-PET intensities was tested using Spearman's rank correlation coefficient (rho), followed by Holm–Bonferroni correction for multiple testing. Results: Neuropsychological testing revealed normal cognitive performance levels in all participants. Mean regional PiB-PET and FLAIR intensities were normally distributed and independent. Significant correlation between volume-normalized PiB-PET signals and FLAIR intensities resulted for Hippocampus (right: rho = 0.86; left: rho = 0.84), Brainstem (rho = 0.85) and left Basal Ganglia vessel region (rho = 0.82). Conclusions: Our finding of a significant relationship between PiB- and FLAIR intensity mainly observable in the Hippocampus and Brainstem, indicates regional Aβ associated tissue-edema in cognitively normal elderly subjects. Further studies including clinical populations are necessary to clarify the relevance of our findings for estimating individual risk for age-related neurodegenerative processes such as AD

    Key features of palliative care service delivery to Indigenous peoples in Australia, New Zealand, Canada and the United States: A comprehensive review

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    Background: Indigenous peoples in developed countries have reduced life expectancies, particularly from chronic diseases. The lack of access to and take up of palliative care services of Indigenous peoples is an ongoing concern. Objectives: To examine and learn from published studies on provision of culturally safe palliative care service delivery to Indigenous people in Australia, New Zealand (NZ), Canada and the United States of America (USA); and to compare Indigenous peoples’ preferences, needs, opportunities and barriers to palliative care. Methods: A comprehensive search of multiple databases was undertaken. Articles were included if they were published in English from 2000 onwards and related to palliative care service delivery for Indigenous populations; papers could use quantitative or qualitative approaches. Common themes were identified using thematic synthesis. Studies were evaluated using Daly’s hierarchy of evidence-for-practice in qualitative research. Results: Of 522 articles screened, 39 were eligible for inclusion. Despite diversity in Indigenous peoples’ experiences across countries, some commonalities were noted in the preferences for palliative care of Indigenous people: to die close to or at home; involvement of family; and the integration of cultural practices. Barriers identified included inaccessibility, affordability, lack of awareness of services, perceptions of palliative care, and inappropriate services. Identified models attempted to address these gaps by adopting the following strategies: community engagement and ownership; flexibility in approach; continuing education and training; a whole-of-service approach; and local partnerships among multiple agencies. Better engagement with Indigenous clients, an increase in number of palliative care patients, improved outcomes, and understanding about palliative care by patients and their families were identified as positive achievements. Conclusions: The results provide a comprehensive overview of identified effective practices with regards to palliative care delivered to Indigenous populations to guide future program developments in this field. Further research is required to explore the palliative care needs and experiences of Indigenous people living in urban areas

    Polygenic risk score, parental socioeconomic status, family history of psychiatric disorders, and the risk for schizophrenia: a Danish population-based study and meta-analysis

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    IMPORTANCE Schizophrenia has a complex etiology influenced both by genetic and nongenetic factors but disentangling these factors is difficult. OBJECTIVE To estimate (1) how strongly the risk for schizophrenia relates to the mutual effect of the polygenic risk score, parental socioeconomic status, and family history of psychiatric disorders; (2) the fraction of cases that could be prevented if no one was exposed to these factors; (3) whether family background interacts with an individual's genetic liability so that specific subgroups are particularly risk prone; and (4) to what extent a proband's genetic makeup mediates the risk associated with familial background. DESIGN, SETTINGS, AND PARTICIPANTS We conducted a nested case-control study based onDanish population-based registers. The study consisted of 866 patients diagnosed as having schizophrenia between January 1, 1994, and December 31, 2006, and 871 matched control individuals. Genome-wide data and family psychiatric and socioeconomic background information were obtained from neonatal biobanks and national registers. Results from a separate meta-analysis (34 600 cases and 45 968 control individuals) were applied to calculate polygenic risk scores. EXPOSURES Polygenic risk scores, parental socioeconomic status, and family psychiatric history. MAIN OUTCOMES AND MEASURES Odds ratios (ORs), attributable risks, liability R2 values, and proportions mediated. RESULTS Schizophrenia was associated with the polygenic risk score (OR, 8.01; 95%CI, 4.53-14.16 for highest vs lowest decile), socioeconomic status (OR, 8.10; 95%CI, 3.24-20.3 for 6 vs no exposures), and a history of schizophrenia/psychoses (OR, 4.18; 95%CI, 2.57-6.79). The R2 values were 3.4%(95%CI, 2.1-4.6) for the polygenic risk score, 3.1%(95%CI, 1.9-4.3) for parental socioeconomic status, and 3.4%(95%CI, 2.1-4.6) for family history. Socioeconomic status and psychiatric history accounted for 45.8% (95%CI, 36.1-55.5) and 25.8% (95%CI, 21.2-30.5) of cases, respectively. There was an interaction between the polygenic risk score and family history (P = .03). A total of 17.4%(95%CI, 9.1-26.6) of the effect associated with family history of schizophrenia/psychoses was mediated through the polygenic risk score. CONCLUSIONS AND RELEVANCE Schizophrenia was associated with the polygenic risk score, family psychiatric history, and socioeconomic status. Our study demonstrated that family history of schizophrenia/psychoses is partly mediated through the individual's genetic liability

    ProPIG - Organic pig health, welfare and environmental impact across Europe

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    Organic production is perceived by consumers as being superior in animal welfare and sustainability and the demand for organic pork products is slowly increasing. Within the past ten years a variety of husbandry and management systems have been developed across the EU, ranging from farms with pigs outdoors all year round using local breeds to farms with housed pigs having concrete outside runs and using conventional breeds (CorePIG, Rousing et al, 2011). So far, mainly clinical parameters have been used to describe the health situation on organic pig farms, identifying some key problems, such as weaning diarrhoea and piglet mortality. Organic pig production is - amongst others - characterised through a holistic approach based on the EU Regulation (EC) No 834/2007 and the IFOAM principles: ‘health, ecology, fairness and care’. This clearly states that health is more than absence of clinical symptoms and, the relation between animals and their environment is identified: ‘Health’ is defined as ‘the wholeness and integrity of living systems. It is not simply the absence of illness, but the maintenance of physical, mental, social and ecological well-being’ (IFOAM; 2006). Concepts of animal welfare include physical and mental welfare as well as the concept of naturalness (Fraser 2003), which is often interpreted as the ability to perform natural behaviour. Verhoog et al (2003) describe three main approaches within organic agriculture’s concept of nature and naturalness: the no-chemicals approach, the agro-ecology approach and the integrity approach. Applying those concepts to organic pig production can highlight potential conflicts: outdoor systems are perceived as the optimal housing system for pigs, as they allow natural behaviour such as rooting. However, this behaviour can cause damage to the grass cover and furthermore the manure fate in outdoor areas needs to be considered. A few studies on outdoor pig production have shown a clear N and P surplus and a high degree of distribution heterogeneity in outdoor areas, increasing the risk of N and P losses (Watson et al. 2003). Robust and competitive organic pig production needs to encompass low environmental impacts and good animal health and welfare. So far few studies have quantified both aspects in different pig husbandry systems. In addition, the theory that improving animal health and welfare reduces environmental impacts through decreased medicine use, improved growth rate and feed conversion efficiency has still to be verified. The aim of the CoreOrganic2 project ProPIG (2011-2014; carried out in eight European countries) is to examine the relationship between health, welfare and environmental impact. On-farm assessment protocols will be carried out on 75 farms in three pig husbandry systems (outdoor, partly outdoor, indoor with concrete outside run). Environmental impact will be assessed using both Life Cycle Assessment and calculations of nutrient balances at farm and outdoor area level. Animal health and welfare will be evaluated from animal based parameters including clinical and selected behavioural parameters. Results will be fed back and used by the farmers to decide farm specific goals and strategies to achieve these goals. As an outcome, all farms will create their individual health, welfare and environmental plan, which will be reviewed after one year to allow continuous development. This will provide the opportunity not only to investigate, but also improve the influence of organic pig farming systems on animal welfare and environmental impact. This fulfils the fourth IFOAM principle of care: ‘Organic Agriculture should be managed in a precautionary and responsible manner to protect the health and well-being of current and future generations and the environment’ (IFOAM, 2006)
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