839 research outputs found

    Control System Design Philosophy for Effective Operations and Maintenance

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    A well-designed control system facilitates the functions of machine operation, maintenance and development. In addition, the overall effectiveness of the control system can be greatly enhanced by providing reliable mechanisms for coordination and communication, ensuring that these functions work in concert. For good operability, the information presented to operators should be consistent, easy to understand and customizable. A maintainable system is segmented appropriately, allowing a broken element to be quickly identified and repaired while leaving the balance of the system available. In a research and development environment, the control system must meet the frequently changing requirements of a variety of customers. This means the system must be flexible enough to allow for ongoing modifications with minimal disruptions to operations. Beyond the hardware and software elements of the control system, appropriate workflow processes must be in place to maximize system uptime and allow people to work efficiently. Processes that provide automatic electronic communication ensure that information is not lost and reaches its destination in a timely fashion. This paper discusses how these control system design and quality issues have been applied at the Thomas Jefferson National Accelerator Facility.Comment: ICALEPCS 200

    Using A Nameserver to Enhance Control System Efficiency

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    The Thomas Jefferson National Accelerator Facility (Jefferson Lab) control system uses a nameserver to reduce system response time and to minimize the impact of client name resolution on front-end computers. The control system is based on the Experimental Physics and Industrial Control System (EPICS), which uses name-based broadcasts to initiate data communication. By default, when EPICS process variables (PV) are requested by client applications, all front-end computers receive the broadcasts and perform name resolution processing against local channel name lists. The nameserver is used to offload the name resolution task to a single node. This processing, formerly done on all front-end computers, is now done only by the nameserver. In a control system with heavily loaded front-end computers and high peak client connection loads, a significant performance improvement is seen. This paper describes the name server in more detail, and discusses the strengths and weaknesses of making name resolution a centralized service.Comment: ICALEPCS 200

    A New Physical Picture for AGNs Lacking Optical Emission Lines

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    In this work, we use ~500 low-redshift (z ~ 0.1) X-ray AGNs observed by XMM-Newton and SDSS to investigate the prevalence and nature of AGNs that apparently lack optical emission lines (``optically dull AGNs''). Although 1/4 of spectra appear absorption-line dominated in visual assessment, line extraction with robust continuum subtraction from the MPA/JHU catalog reveals usable [OIII] measurements in 98% of the sample, allowing us to study [OIII]-underluminous AGNs together with more typical AGNs in the context of the L[OIII]_{\mathrm{[OIII]}}--LX_{X} relation. We find that ``optically dull AGNs'' do not constitute a distinct population of AGNs. Instead, they are the [OIII]-underluminous tail of a single, unimodal L[OIII]_{\mathrm{[OIII]}}--LX_{X} relation that has substantial scatter (0.6 dex). We find the degree to which an AGN is underluminous in [OIII] correlates with the specific SFR or D4000_{4000} index of the host, which are both linked to the molecular gas fraction. Thus the emerging physical picture for the large scatter seems to involve the gas content of the narrow-line region. We find no significant role for previously proposed scenarios for the presence of optically dull AGNs, such as host dilution or dust obscuration. Despite occasionally weak lines in SDSS spectra, >80% of X-ray AGNs are identified as such with the BPT diagram. >90% are classified as AGNs based only on [NII]/Hα\alpha, providing more complete AGN samples when [OIII] or Hβ\beta are weak. X-ray AGNs with LINER spectra obey essentially the same \lxo\ relation as Seyfert 2s, suggesting their line emission is produced by AGN activity.Comment: 21 pages, 14 figures, submitted to ApJ. Comments welcom

    Self-harm in women in midlife: rates, precipitating problems, and outcomes following hospital presentations in the Multicentre Study of Self-harm in England

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    Background: Suicide in women in the UK is highest in those in midlife. Characteristics associated with self-harm are also known to differ from men in this age-group. Given the unique changes in biological, social, and economic risk factors typically experienced by women in midlife, more detailed information is needed to inform care. Aim: To investigate rates, characteristics, and outcomes of self-harm in women in midlife compared to younger women and identify differences within the midlife age-group. Method: Data on women aged 40-59 years from the Multicentre Study of Self-harm in England from 2003 to 2016 were used, including mortality follow-up to 2019. Data were collected via specialist assessments or directly from emergency department records. Trends were assessed using negative binomial regression models. Comparative analysis used chi-square tests of association. Self-harm repetition and suicide mortality analyses used Cox proportional hazards models. Results: The self-harm rate in midlife women was 435 per 100,000 population and was relatively stable over time (incident rate ratio [IRR] 0.99, p<0.01). Midlife women reported more problems around finances, alcohol use, along with physical and mental health problems. Within-group comparisons showed suicide was more common in older women in midlife (Hazard Ratio [HR] 2.20, p<0.01). Intensity of clinical care, as measured by psychosocial assessment and psychiatric inpatient admission, also increased with age. Conclusion: Addressing issues relating to finances, mental health and alcohol misuse, alongside the social and biological transitions associated with midlife, may help to reduce self-harm in women during this period. Alcohol misuse was important across all stages of midlife, whereas physical health problems and experiencing bereavement increased with age. Despite receiving more intensive follow-up care, the suicide risk in older midlife women was elevated, perhaps indicating the need for more targeted support. Awareness of these potential vulnerabilities may help inform clinicians’ risk formulation and safety planning

    Transverse Spin at PHENIX: Results and Prospects

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    The Relativistic Heavy Ion Collider (RHIC), as the world's first and only polarized proton collider, offers a unique environment in which to study the spin structure of the proton. In order to study the proton's transverse spin structure, the PHENIX experiment at RHIC took data with transversely polarized beams in 2001-02 and 2005, and it has plans for further running with transverse polarization in 2006 and beyond. Results from early running as well as prospective measurements for the future will be discussed.Comment: 6 pages, 2 figures, presented at Transversity 2005, Como, Ital

    Setting the international research agenda for sarcomas with patients and carers:results of phase II of the Sarcoma Patient Advocacy Global Network (SPAGN) priority setting partnership

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    Background: Typically, researchers and clinicians determine the agenda in sarcoma research. However, patient involvement can have a meaningful impact on research. Therefore, the Patient-Powered Research Network (PPRN) of the Sarcoma Patient Advocacy Global Network (SPAGN) set up a Priority Setting Partnership (PSP). The primary objective of this partnership is to identify priorities for research and patient advocacy topics. Methods: In the first phase of this PSP, including 264 sarcoma patients and carers from all over the world, 23 research topics regarding sarcomas and 15 patient advocacy topics were identified using an online survey. In the second phase, participants were asked to fill in a top five and a top three of research and patient advocacy topics, respectively. Additionally, sociodemographic characteristics and sarcoma characteristics were collected. Social media channels, local national patient advocacy groups and the SPAGN website were used to distribute the survey. Results: In total, 671 patients (75%) and carers (25%) participated in this survey. The five highest ranked research topics were related to causes of sarcoma (43%), prognosis and risk of recurrence (40%), specific subtypes of sarcoma (33%), the role of immunotherapy, targeted therapy and combined therapy (30%), and hereditary aspects (30%). The three highest ranked patient advocacy topics were improving the diagnostic process of sarcoma (39%), access to tumor DNA analysis (37%) and establishing an international sarcoma registry (37%). Conclusions: This sarcoma PSP has identified priorities for research and patient advocacy, offering guidance for researchers, assisting funding agencies with assessing project relevance and empowering patient advocates to represent the needs of patients and carers.</p

    Charged-Particle Pseudorapidity Distributions in Au+Au Collisions at sqrt(s_NN)=62.4 GeV

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    The charged-particle pseudorapidity density for Au+Au collisions at sqrt(s_NN)=62.4 GeV has been measured over a wide range of impact parameters and compared to results obtained at other energies. As a function of collision energy, the pseudorapidity distribution grows systematically both in height and width. The mid-rapidity density is found to grow approximately logarithmically between AGS energies and the top RHIC energy. As a function of centrality, there is an approximate factorization of the centrality dependence of the mid-rapidity yields and the overall multiplicity scale. The new results at sqrt(s_NN)=62.4 GeV confirm the previously observed phenomenon of ``extended longitudinal scaling'' in the pseudorapidity distributions when viewed in the rest frame of one of the colliding nuclei. It is also found that the evolution of the shape of the distribution with centrality is energy independent, when viewed in this reference frame. As a function of centrality, the total charged particle multiplicity scales linearly with the number of participant pairs as it was observed at other energies.Comment: 6 pages, 7 figures, submitted to Phys. Rev. C - Rapid Communication

    System Size, Energy, Pseudorapidity, and Centrality Dependence of Elliptic Flow

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    This paper presents measurements of the elliptic flow of charged particles as a function of pseudorapidity and centrality from Cu-Cu collisions at 62.4 and 200 GeV using the PHOBOS detector at the Relativistic Heavy Ion Collider (RHIC). The elliptic flow in Cu-Cu collisions is found to be significant even for the most central events. For comparison with the Au-Au results, it is found that the detailed way in which the collision geometry (eccentricity) is estimated is of critical importance when scaling out system-size effects. A new form of eccentricity, called the participant eccentricity, is introduced which yields a scaled elliptic flow in the Cu-Cu system that has the same relative magnitude and qualitative features as that in the Au-Au system

    Latest Results from PHOBOS

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    This manuscript contains a summary of the latest physics results from PHOBOS, as reported at Quark Matter 2006. Highlights include the first measurement from PHOBOS of dynamical elliptic flow fluctuations as well as an explanation of their possible origin, two-particle correlations, identified particle ratios, identified particle spectra and the latest results in global charged particle production.Comment: 9 pages, 7 figures, PHOBOS plenary proceedings for Quark Matter 200

    System size, energy, centrality and pseudorapidity dependence of charged-particle density in Au+Au and Cu+Cu collisions at RHIC

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    Charged particle pseudorapidity distributions are presented from the PHOBOS experiment at RHIC, measured in Au+Au and Cu+Cu collisions at sqrt{s_NN}=19.6, 22.4, 62.4, 130 and 200 GeV, as a function of collision centrality. The presentation includes the recently analyzed Cu+Cu data at 22.4 GeV. The measurements were made by the same detector setup over a broad range in pseudorapidity, |eta|<5.4, allowing for a reliable systematic study of particle production as a function of energy, centrality and system size. Comparing Cu+Cu and Au+Au results, we find that the total number of produced charged particles and the overall shape (height and width) of the pseudorapidity distributions are determined by the number of nucleon participants, N_part. Detailed comparisons reveal that the matching of the shape of the Cu+Cu and Au+Au pseudorapidity distributions over the full range of eta is better for the same N_part/2A value than for the same N_part value, where A denotes the mass number. In other words, it is the geometry of the nuclear overlap zone, rather than just the number of nucleon participants that drives the detailed shape of the pseudorapidity distribution and its centrality dependence.Comment: 5 pages, 4 figures. Presented at the 20th International Conference on Nucleus-Nucleus Collisions (Quark Matter 2008), Jaipur, Rajasthan, India, 4-10 February 200
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