711 research outputs found

    High power, ultra-broadband supercontinuum source based on highly GeO2 doped silica fiber

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    We demonstrate a 74 mol % GeO2 doped fiber for mid-infrared supercontinuum generation. Experiments ensure a highest output power for a broadest spectrum from 700nm to 3200nm from this fiber, while being pumped by a broadband 4 stage Erbium fiber based MOPA. The effect of repetition rate of pump source and length of Germania-doped fiber has also been investigated. Further, Germania doped fiber has been pumped by conventional Silica based photonic crystal fiber supercontinuum source. At low power, a considerable broadening of 200-300nm was observed. Further broadening of spectrum was limited due to limited power of pump source. Our investigations reveal the unexploited potential of Germania doped fiber for mid-infrared supercontinuum generation. This measurement ensures a possibility of Germania based photonic crystal fiber or a step-index fiber supercontinuum source for high power ultra-broad band emission being pumped a 1060nm or a 1550nm laser source. To the best of our knowledge, this is the record power, ultra-broadband, and all-fiberized SC light source based on Silica and Germania fiber ever demonstrated to the date

    The incidence and outcome of septic shock patients in the absence of early-goal directed therapy

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    INTRODUCTION: The purpose of the present study was to measure the incidence and outcome of septic patients presenting at the emergency department (ED) with criteria for early goal-directed therapy (EGDT). METHOD: This hospital-based, retrospective, observational study using prospectively collected electronic databases was based in a teaching hospital in Melbourne, Australia. We conducted outcome-blinded electronic screening of patients with infection admitted via the ED from 1 January 2000 to 30 June 2003. We obtained data on demographics, laboratory and clinical features on admission. We used paper records to confirm electronic identification of candidates for EGDT and to study their treatment. We followed up all patients until hospital discharge or death. RESULTS: Of 4,784 ED patients with an infectious disease diagnosis, only 50 fulfilled published clinical inclusion criteria for EGDT (EGDT candidates). Of these patients, 37 (74%) survived their hospital admission, two (4%) died in the ED, eight (16%) died in the intensive care unit and three (6%) died in the ward. After review of all ward cardiac arrests and non-NFR ('not for resuscitation') ward deaths, we identified a further two potential candidates for EGDT for an overall mortality of 28.8% (15 out of 52 patients). Analysis of treatment showed that twice as many (70%) of the EGDT candidates received vasopressor therapy in the ED, and their initial mean central venous pressure (10.8 mmHg) was almost twice that in patients from the EGDT study conducted by Rivers and coworkers. CONCLUSION: In an Australian teaching hospital candidates for EGDT were uncommon and, in the absence of an EGDT protocol, their mortality was lower than that reported with EGDT

    Improvement design of existing threshing machine at Kilang Sawit Risda, Ulu Keratong

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    Palm oil is very important in the agricultural and economic sectors in Malaysia. It’s origin is in the tropical rain forest region of West Africa, which the main belt runs through the southern latitudes of Cameron, Cote D’ ivoire, Ghana, Liberia, Nigeria, Sierria Leone, Togo and into the equatorial region of Angola and the Congo (FAO,2004). The crude palm oil have a very wide range of application which is about 80% of the crude palm oil (CPO) produced can be converted into food products while the others can be used as non-food applications. The by-products or wasted product of palm oil fruit processing such as empty bunches and fibers can be processed as raw materials for potash fertilizer, pulp and paper manufacturing. The shell fragments can be used as renewable energy as fuels and also for decoration of living apartments

    Developing a Research Mentorship Program: The American Society of Pediatric Nephrology's Experience

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    Background: Most pediatric nephrologists work in academia. Mentor-mentee relationships provide support and guidance for successful research career. Mentorship program implementation is valuable in medical fields for providing research opportunities to young faculty. Methods: The American Society of Pediatric Nephrology (ASPN) established a research mentorship program to (a) assist with matching of appropriate mentor-mentee dyads and (b) establish metrics for desirable mentor-mentee outcomes with two independent components: (1) the grants review workshop, a short-term program providing mentor feedback on grant proposals, and (2) the longitudinal program, establishing long-term mentor-mentee relationships. Regular surveys of both mentors and mentees were reviewed to evaluate and refine the program. Results: Twelve mentees and 17 mentors participated in the grant review workshop and 19 mentees were matched to mentors in the longitudinal program. A review of NIH RePORTER data indicated that since 2014, 13 NIH grants have been awarded. Mentees in the longitudinal program reported that the program helped most with identifying an outside mentor, improving grant research content, and with general career development. Mentors perceived themselves to be most helpful in assisting with overall career plans. Email communications were preferred over phone or face-to-face communications. Mentees endorsed strong interest in staying in touch with their mentors and 100% of mentors expressed their willingness to serve in the future. Conclusion: This mentorship program was initiated and supported by a relatively small medical society and has shown early success in cultivating mentoring relationships for a future generation of clinician-scientists

    Probing the Balance of AGN and Star-Forming Activity in the Local Universe with ChaMP

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    The combination of the SDSS and the Chandra Multiwavelength Project (ChaMP) currently offers the largest and most homogeneously selected sample of nearby galaxies for investigating the relation between X-ray nuclear emission, nebular line-emission, black hole masses, and properties of the associated stellar populations. We present here novel constraints that both X-ray luminosity Lx and X-ray spectral energy distribution bring to the galaxy evolutionary sequence H II -> Seyfert/Transition Object -> LINER -> Passive suggested by optical data. In particular, we show that both Lx and Gamma, the slope of the power-law that best fits the 0.5 - 8 keV spectra, are consistent with a clear decline in the accretion power along the sequence, corresponding to a softening of their spectra. This implies that, at z ~ 0, or at low luminosity AGN levels, there is an anti-correlation between Gamma and L/Ledd, opposite to the trend exhibited by high z AGN (quasars). The turning point in the Gamma -L/Ledd LLAGN + quasars relation occurs near Gamma ~ 1.5 and L/Ledd ~ 0.01. Interestingly, this is identical to what stellar mass X-ray binaries exhibit, indicating that we have probably found the first empirical evidence for an intrinsic switch in the accretion mode, from advection-dominated flows to standard (disk/corona) accretion modes in supermassive black hole accretors, similar to what has been seen and proposed to happen in stellar mass black hole systems. The anti-correlation we find between Gamma and L/Ledd may instead indicate that stronger accretion correlates with greater absorption. Therefore the trend for softer spectra toward more luminous, high redshift, and strongly accreting AGN/quasars could simply be the result of strong selection biases reflected in the dearth of type 2 quasar detections.Comment: 23 pages, 8 figures, 1 long (3 page) table, to appear in Ap

    Investigative Study on Preprint Journal Club as an Effective Method of Teaching Latest Knowledge in Astronomy

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    As recent advancements in physics and astronomy rapidly rewrite textbooks, there is a growing need in keeping abreast of the latest knowledge in these fields. Reading preprints is one of the effective ways to do this. By having journal clubs where people can read and discuss journals together, the benefits of reading journals become more prevalent. We present an investigative study of understanding the factors that affect the success of preprint journal clubs in astronomy, more commonly known as Astro-ph/Astro-Coffee (hereafter called AC). A survey was disseminated to understand how institutions from different countries implement AC. We interviewed 9 survey respondents and from their responses we identified four important factors that make AC successful: commitment (how the organizer and attendees participate in AC), environment (how conducive and comfortable AC is conducted), content (the discussed topics in AC and how they are presented), and objective (the main goal/s of conducting AC). We also present the format of our AC, an elective class which was evaluated during the Spring Semester 2020 (March 2020 - June 2020). Our evaluation with the attendees showed that enrollees (those who are enrolled and are required to present papers regularly) tend to be more committed in attending compared to audiences (those who are not enrolled and are not required to present papers regularly). In addition, participants tend to find papers outside their research field harder to read. Finally, we showed an improvement in the weekly number of papers read after attending AC of those who present papers regularly, and a high satisfaction rating of our AC. We summarize the areas of improvement in our AC implementation, and we encourage other institutions to evaluate their own AC in accordance with the four aforementioned factors to assess the effectiveness of their AC in reaching their goals.Comment: Accepted for publication in PRPER. A summary video is available at http://www.youtube.com/watch?v=fzy2I_xA_dU&ab_channel=NthuCosmolog

    Can luminous Lyman alpha emitters at zz ≃\simeq 5.7 and zz ≃\simeq 6.6 suppress star formation?

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    Addressing how strong UV radiation affects galaxy formation is central to understanding their evolution. The quenching of star formation via strong UV radiation (from starbursts or AGN) has been proposed in various scenes to solve certain astrophysical problems. Around luminous sources, some evidence of decreased star formation has been found but is limited to a handful of individual cases. No direct, conclusive evidence on the actual role of strong UV radiation in quenching star formation has been found. Here we present statistical evidence of decreased number density of faint (AB magnitude ≥\geq 24.75 mag) Ly\alpha emitters (LAEs) around bright (AB magnitude < 24.75 mag) LAEs even when the radius goes up to 10 pMpc for zz ≃\simeq 5.7 LAEs. A similar trend is found for z ≃\simeq 6.6 LAEs but only within 1 pMpc radius from the bright LAEs. We use a large sample of 1077 (962) LAEs at zz ≃\simeq 5.7 (zz ≃\simeq 6.6) selected in total areas of 14 (21) deg2^2 with Subaru/Hyper Suprime-Cam narrow-band data, and thus, the result is of statistical significance for the first time at these high redshift ranges. A simple analytical calculation indicates that the radiation from the central LAE is not enough to suppress LAEs with AB mag ≥\geq 24.75 mag around them, suggesting additional physical mechanisms we are unaware of are at work. Our results clearly show that the environment is at work for the galaxy formation at zz ∼\sim 6 in the Universe.Comment: Accepted for publication at MNRA

    Forgiveness of In-group Offenders in Christian Congregations

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    Religious communities, like other communities, are ripe for interpersonal offenses. We examined the degree to which group identification predicted forgiveness of an in-group offender. We examined the effects of a victim’s perception of his or her religious group identification as a state-specific personal variable on forgiveness by integrating Social Identity Theory into a model of Relational Spirituality (Davis, Hook, & Worthington, 2008) to help explain victim’s responses to transgressions within a religious context. Data were collected from members of Christian congregations from the mid-west region of the United States (Study 1, N = 63), and college students belonging to Christian congregations (Study 2, N = 376). Regression analyses demonstrated that even after statistically controlling for many religious and transgression-related variables, group identification with a congregation still predicted variance in revenge and benevolence toward an in-group offender after a transgression. Additionally, mediation analyses suggest group identification as one mechanism through which trait forgivingness relates to forgiveness of specific offenses. We discuss the importance of group identity in forgiving other in-group members in a religious community
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