2,714 research outputs found

    Motion Planning for Simple Two-Wheeled Robots

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    This paper considers various simple ways of navigating in a 2-dimensianal territory with a two-wheeled robot of a type typical in educational robotics. We determine shortest paths under various modes of operation and compare

    Tunable Integrated-Optics Nanoscaled Devices Based on Magnetic Photonic Crystals

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    Magnetooptical properties of magnetic photonic crystals have been investigated in the view of their possible applications for the modern integrated-optics devices. A "transfer matrices" formalism was expanded for the case of oblique light incidence on the periodic nanoscaled magnetic multilayered systems. Several new effects such as the Faraday effect dependence on the incidence angle and the tunability of the bandgap defect modes spectral location by external magnetic fields were found. Several possibilities of one-dimensional magnetic photonic crystals applications for the optical devices are discussed. Initial steps towards the practical implementation of the proposed devices are reported.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

    A Scoping Review of the Factors That Influence Families’ Ability or Capacity to Provide Young People With Emotional Support Over the Transition to Adulthood

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    The transition to adulthood is typically marked by changes in relationships with family members, peers, and romantic partners. Despite this, the family often maintains a prominent role in young adults’ lives. A scoping review was conducted to identify the factors that influence families’ ability or capacity to provide young people with emotional support during the transition to adulthood, and to understand the gaps in this research area. Title and abstract searches were conducted from January 2007 to February 2021 in multiple databases, including PsycINFO, MEDLINE, and Sociological Abstracts. Fifteen semi-structured interviews were also conducted with stakeholders (professionals from relevant sectors/working within this field). In total, 277 articles were eligible for inclusion in the review. Following data extraction, 19 factors were identified. Factors with the most research (more than 20 articles) included: family proximity or co-residence; mental health; sex or gender differences; and family communication. Factors with less research included: societal context; young person’s sexual orientation or gender identity; social networks; and adverse life events. Gaps in the research area were also identified, including methodological issues (e.g., lack of mixed methods and longitudinal study designs), a disproportionate focus on the parent–child relationship, and a lack of contextually situated research. Our findings indicate that future research in this area could benefit from taking an intersectional, multi-method approach, with a focus on the whole family and diverse samples

    Quality assurance of 61Cu using ICP mass spectroscopy and metal complexation

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    Introduction 61Cu (T1/2 = 3.33 hr, Eβ= 1.22 MeV, 61.4 %) is an attractive isotope for positron emission tomography (PET) radiopharmaceutical agents such as ATSM and PTSM. Various separation processes have been reported for the production of 61Cu on a medium cyclotron using 13–22 MeV protons on natural and enriched 64Zn target materials [1,2]. This work, investigates production of 61Cu using both natural and enriched 64Zn targets and its separation. Three types of resins were used to assess for their efficiency and speed to separate the desired 61Cu from the 66,67,68Ga and 64Zn and for the recycling of 64Zn target material. The effective specific activity of purified 61Cu, was determined by ICP-MS and its titration with various polyaza and polycarboxylate complexing ligands. Material and Methods 1. Production and Separation Targets were irradiated by proton beam of IBA cyclotron 18/18MeV via the 64Zn(p,α) 61Cu and natZn(p,x) 61Cu reactions using an enriched 64Zn foil(15×15×0.05mm, ~50 mg) and natural foil (diameter 25 mm, 0.05 mm,~ 60 mg). Thirty minute irradiations were conducted with incident proton energies between 11.7–12.0 MeV and beam currents of 20 and 40 µA. Irradiated Zn targets were dissolved in 8M HCl at 150 oC then evaporated to dryness. Trace water to the resultant residue (twice) and resultant solutions evaporated to dryness. The residue was re-dissolved in 2ml of 0.01M HCl before loading onto a Cu-resin column (FIG. 1) Zn and Ga isotopes were collectively eluted using 30 ml of 0.01M HCl. The Cu was then removed using 1.5 ml of 8M HCl and passed directly onto a cation exchange followed by an anion exchange column. An additional 3 ml of 8M HCl was used to rinse the cation exchange column and ensure quantitatively removal of Cu (II) ions. The Cu was finally eluted from the anion exchange column using 3 ml of 2M HCl. The Cu solution was heated up at 150 oC until evaporated to dryness and 61Cu final product dissolved in 400–800 μL of 0.01M HCl. 2. Specific activity of 61Cu The specific activity (GBq/µmol) of the purified 61Cu was determined by ICP-MS and compared with that determined using dota, nota and di-amsar complexing ligands. For each 61Cu production run aliquot of final solution (100 µL) was left to decay before dilut-ing to 10 mL with 10% HNO3. Decayed samples were sent to ChemCentre (Curtin University) for ICP-MS analysis. Each sample was analysed for Cu, Al, Ca, Co, Fe, Ga, Ni, Si, and Zn, which are known to compete with Cu2+ for ligand complexation. Effective specific activity of the 61Cu was deter-mined by titrating various known concentration of ligands with 61Cu solution. The method is detailed in the literature [3]. Briefly, varying concentrations of each ligand was prepared in 0.1M sodium acetate buffer pH 6.5 to a total volume 20 µL. Fixed concentration of diluted 61Cu (0.01M HCl) in 10 µL was added to each ligand solution. The mixtures were vortexed then left to incubate at the room temperature for 30 mins. Two uL aliquots were withdrawn (in triplicate) from each reaction mixture and spot-ted on ITLC –SA. [Mobile phase: 0.1M NaCl: 0.1M EDTA (9:1) for Cu2+ and diamsar mixtures: Rf 0.8 free Cu2+ and 0.1M sodium acetate pH 4.5: H2O: MeOH: ammonium hydroxide (20:18:2:1 v/v) for Cu2+ dota and nota mixtures: Rf >0.8 Cu-dota and Cu-nota Rf < 0.2 free Cu2+]. Complexation of the 61Cu with each ligand was complete within 30 mins at room temperature. Concentration of Cu2+ was deter-mined from the 50% labelling efficiency. Results and Conclusion 1. Production and Separation The radioisotopes production from natZn target must be minimized by the optimum proton energy to reduce a radiation dose in the final product. The excitation functions of 66,67,68Ga ,65Zn and 61Cu are shown in FIG. 2. Proton beam energy of 11.7 MeV was used for both Zn targets to minimise the production of Ga isotopes and prevent formation of 65Zn. For the enriched 64Zn target (99.30%) higher proton energy could be used for the production of 61Cu allowing for increased yields and reduce radio contaminants. Previously, we used anion and cation exchange resin as described in the literature to separate the 61Cu [1]. Unfortunately the literature method was too long (up to 3 hours) and requiring high concentration of HCl and long evaporation times compromising achievable yields [4]. Thieme S. et al., 2013 [2] reported the successful use of Cu-resin for the separation of Cu radioisotopes and it was of interest to the current work to test this material for the separation of 61Cu in our hands. A cation, anion exchange and Cu-resin were combined into closed system to separate the 61Cu within 30 mins (FIG. 1). The system is designed to contain the transfer of solutions be-tween each column using simple plunger to force solution through and between each column. This system afforded an easy, reliable and fast separation of 61Cu that could be completed within 30 min. 2. Specific activity The specific activity of 61Cu was determined using ICP-MS and by titration with three ligands is summarized in TABLE 1. The ICP-MS data show values ranging from 9.2 to 32.4 GBq/μmol for 8 production runs. Specific activity determine using nota and dota were in all cases lower than the ICP MS data indicating some interference from the other metal ion contaminates such as Fe(ii/Iii), Ni (II), Ca (II), Zn (II), Ga (III). The specific activity determine using diamsar, which is known to be highly selective for Cu(II) (and Zn(II) and Fe(III)) in the presence of alkali and alkaline earth ions gave values significantly higher effective specific activity than that obtained using ICP MS. Variations in values can be explained by presence of contaminating metal ions

    Diabetes Medication Assistance Service: The pharmacist's role in supporting patient self-management of type 2 diabetes (T2DM) in Australia

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    Objective. To evaluate the capacity and effectiveness of trained community pharmacists in delivering the Diabetes Medication Assistance Service (DMAS) via (1) number and types of self-management support interventions (SMSIs); (2) number of goals set and attained by patients and (3) patient outcomes (glycaemic control, medication adherence and satisfaction). Methods. Pharmacists (n = 109) from 90 community pharmacies in Australia were trained and credentialed to deliver the DMAS. The training focused on developing pharmacists’ knowledge and skills in supporting patients’ diabetes self-management. Results. A total of 387 patients completed the trial. The mean number of SMSIs per patient was 35 (SD ±31) and the majority (87%) had at least one documented goal that was fully or partially attained. There were significant health benefits for patients including improved glycaemic control and a reduced risk of non-adherence to medications. Over 90% of DMAS patients reported improvements in their knowledge about diabetes self-management.Conclusion. The DMAS provides self management support in the community pharmacy for people with T2DM which may result in improved clinical outcomes. Practice implication. Given appropriate training in diabetes care and behavior change strategies, community pharmacists can offer programs which provide self-management support to their patients with T2DM and improve their health outcomes

    Experimental Investigation of Flow Condensation in Microgravity

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    Future manned missions to Mars are expected to greatly increase the space vehicle's size, weight, and heat dissipation requirements. An effective means to reducing both size and weight is to replace single-phase thermal management systems with two-phase counterparts that capitalize upon both latent and sensible heat of the coolant rather than sensible heat alone. This shift is expected to yield orders of magnitude enhancements in flow boiling and condensation heat transfer coefficients. A major challenge to this shift is a lack of reliable tools for accurate prediction of two-phase pressure drop and heat transfer coefficient in reduced gravity. Developing such tools will require a sophisticated experimental facility to enable investigators to perform both flow boiling and condensation experiments in microgravity in pursuit of reliable databases. This study will discuss the development of the Flow Boiling and Condensation Experiment (FBCE) for the International Space Station (ISS), which was initiated in 2012 in collaboration between Purdue University and NASA Glenn Research Center. This facility was recently tested in parabolic flight to acquire condensation data for FC-72 in microgravity, aided by high-speed video analysis of interfacial structure of the condensation film. The condensation is achieved by rejecting heat to a counter flow of water, and experiments were performed at different mass velocities of FC-72 and water and different FC-72 inlet qualities. It is shown that the film flow varies from smooth-laminar to wavy-laminar and ultimately turbulent with increasing FC-72 mass velocity. The heat transfer coefficient is highest near the inlet of the condensation tube, where the film is thinnest, and decreases monotonically along the tube, except for high FC-72 mass velocities, where the heat transfer coefficient is enhanced downstream. This enhancement is attributed to both turbulence and increased interfacial waviness. One-ge correlations are shown to predict the average condensation heat transfer coefficient with varying degrees of success, and a recent correlation is identified for its superior predictive capability, evidenced by a mean absolute error of 21.7%

    What are the hot R Coronae Borealis stars?

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    We investigate the evolutionary status of four stars: V348 Sgr, DY Cen, and MV Sgr in the Galaxy and HV 2671 in the LMC. These stars have in common random deep declines in visual brightness, which are characteristic of R Coronae Borealis (RCB) stars. RCB stars are typically cool hydrogen-deficient supergiants. The four stars studied in this paper are hotter (Teff = 15–20 kK) than the majority of RCB stars (Teff = 5000–7000 K). Although these are commonly grouped together as the hot RCB stars they do not necessarily share a common evolutionary history. We present new observational data and an extensive collection of archival and previously published data that is reassessed to ensure internal consistency. We find temporal variations of various properties on different timescales that will eventually help us to uncover the evolutionary history of these objects. DY Cen and MV Sgr have typical RCB helium abundances, which exclude any currently known post–asymptotic giant branch (post-AGB) evolutionary models. Moreover, their carbon and nitrogen abundances present us with further problems for their interpretation. V348 Sgr and HV 2671 are in general agreement with a born-again post-AGB evolution, and their abundances are similar to Wolf-Rayet central stars of planetary nebulae (PNs). The three Galactic stars in the sample have circumstellar nebulae, which produce forbidden line radiation (for HV 2671 we have no information). V348 Sgr and DY Cen have low-density, low-expansion velocity nebulae (resolved in the case of V348 Sgr), while MV Sgr has a higher density, higher expansion velocity nebula. All three stars, on the other hand, have split emission lines, which indicate the presence of an equatorial bulge but not of a Keplerian disk. In addition, the historical light curves for the three Galactic hot RCB stars show evidence for a significant fading in their maximum-light brightnesses of ~1 mag over the last 70 yr. From this we deduce that their effective temperatures increased by a few thousand degrees. If V348 Sgr is a born-again star, as we presume, this means that the star is returning from the born-again AGB phase to the phase of a central star of PN. Spectroscopically, no dramatic change is observed over the last 50 years for V348 Sgr and MV Sgr. However, there is some evidence that the winds of V348 Sgr and DY Cen have increased in strength in the last decade. HV 2671, located in the LMC, has not been analyzed in detail but at 5 Å… resolution is almost identical to V348 Sgr. Through the bolometric correction derived for V348 Sgr and the known distance, we can estimate the absolute ν magnitude of HV 2671 (Mν = -3.0 mag) and its bolometric luminosity (~6000 L⊙)

    Optical Spectropolarimetry of SN 2002ap: High Velocity Asymmetric Explosion

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    We present spectropolarimetry of the Type Ic supernova SN 2002ap and give a preliminary analysis: the data were taken at two epochs, close to and one month later than the visual maximum (2002 February 8). In addition we present June 9 spectropolarimetry without analysis. The data show the development of linear polarization. Distinct polarization profiles were seen only in the O I \lambda 7773 multiplet/Ca II IR triplet absorption trough at maximum light and in the Ca II IR triplet absorption trough a month later, with the latter showing a peak polarization as high as ~2 %. The intrinsic polarization shows three clear position angles: 80 degs for the February continuum, 120 degs for the February line feature, and 150 degs for the March data. We conclude that there are multiple asymmetric components in the ejecta. We suggest that the supernova has a bulk asymmetry with an axial ratio projected on the sky that is different from 1 by of order 10 %. Furthermore, we suggest very speculatively that a high velocity ejecta component moving faster than ~0.115c (e.g., a jet) contributes to polarization in the February epoch.Comment: 7 pages, 3 figures, accepted for publication in the Astrophysical Journal (Letters

    Predictive value of midtrimester universal cervical length screening based on parity

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    OBJECTIVES: To evaluate the effect of parity on performance characteristics of midtrimester cervical length (CL) in predicting spontaneous preterm birth (sPTB) before 37 weeks. METHODS: This was a retrospective cohort study of 13,508 women with no history of sPTB undergoing universal transvaginal CL screening at 17 to 23 weeks\u27 gestation from 2011 to 2016. Patients who declined screening or with unknown delivery outcomes were excluded. Areas under the receiver operator characteristic curves were used to assess and compare the predictive ability of CL screening for sPTB. The sensitivity, specificity, and positive and negative predictive values were estimated for specific CL cutoffs for prediction of sPTB. RESULTS: There were 20,100 patients, of whom 2087 (10%) declined screening and 4505 (22%) did not meet inclusion criteria. Of the remaining 13,508 patients, 43% were nulliparous. The incidence rates of sPTB were 6.5% in nulliparas and 4.9% in multiparas (P \u3c .001). The mean CLs were 39.9 mm in nulliparas and 41.8 mm in multiparas (P \u3c .001), and those of the first percentiles were 19.0 mm in nulliparas and 24.0 mm in multiparas. Cervical length was significantly more predictive of sPTB in nulliparas (area under the curve, 0.67; 95% confidence interval, 0.63-0.70; versus 0.61, 95% confidence interval, 0.57-0.63; P = .008). At CL cutoffs of 10, 15, 20, and 25 mm or less, the sensitivity was lower in multiparas, and the specificity was comparable between the groups. CONCLUSIONS: Midtrimester CL is less predictive of sPTB in multiparas compared to nulliparas. The poor predictive ability, especially in multiparas, calls into question the value of universal CL screening in this population
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