2,466 research outputs found

    Ports and Ladders: The Nature and Relevance of Internal Labor Markets in a Changing World

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    [Excerpt] Many believe that the nature of careers has changed dramatically in the past twenty years. One scholar writes that internal labor markets have been \u27demolished\u27, while a human resources manager at Intel comments that, in contrast to the past, today, \u27You own your own employability. You are responsible\u27 (Knoke 2001: 31). The idea of the \u27boundaryless career\u27 seems increasingly popular (Arthur and Rousseau 1996). If it is in fact true that the old rules for organizing work have disappeared, this would represent a fundamental change for employees. It would also have major implications for how scholars think about the labor market. Not surprisingly, the reality is more complicated, with evidence of both change and stability in the nature of the employment relationship. In this chapter we discuss the nature of these developments and their implications for the internal labor market literature

    CONSUMER PREFERENCES FOR ELECTRICITY FROM BIOENERGY AND OTHER RENEWABLES

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    This study ascertains residential electricity consumers' support and willingness to pay for electricity from renewable sources. Then, willingness to pay for specified renewable energy sources (solar, wind, landfill wastes, bioenergy from fast growing crops, and bioenergy from forest products wastes). Effects of demographics and environmental behaviors are estimated.Institutional and Behavioral Economics,

    The use and effectiveness of the eLib subject gateways: a preliminary investigation

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    Internet subject gateways were set up under the Electronic Libraries Programme (eLib) in order to address some of the problems of searching the Internet which have been identified by information professionals, i.e. locating relevant, good quality information. This preliminary study examines the extent to which academics in two universities use three eLib subject gateways (EEVL, OMNI and SOSIG). The results are generally encouraging for the eLib programme, but it is necessary for the gateways to be more effectively promoted. The study also found that academics do not have the same misgivings about the general search engines as the information professionals and seem to use them more readily than the gateways

    Why do people not attend for treatment for trachomatous trichiasis in Ethiopia? A study of barriers to surgery.

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    BACKGROUND: Trachomatous trichiasis (TT) surgery is provided free or subsidised in most trachoma endemic settings. However, only 18-66% of TT patients attend for surgery. This study analyses barriers to attendance among TT patients in Ethiopia, the country with the highest prevalence of TT in the world. METHODOLOGY/PRINCIPAL FINDINGS: Participants with previously un-operated TT were recruited at 17 surgical outreach campaigns in Amhara Region, Ethiopia. An interview was conducted to ascertain why they had not attended for surgery previously. A trachoma eye examination was performed by an ophthalmologist. 2591 consecutive individuals were interviewed. The most frequently cited barriers to previous attendance for surgery were lack of time (45.3%), financial constraints (42.9%) and lack of an escort (35.5% in females, 19.6% in males). Women were more likely to report a fear of surgery (7.7% vs 3.2%, p<0.001) or be unaware of how to access services (4.5% vs 1.0% p<0.001); men were more frequently asymptomatic (19.6% vs 10.1%, p<0.001). Women were also less likely to have been previously offered TT surgery than men (OR = 0.70, 95%CI 0.53-0.94). CONCLUSIONS/SIGNIFICANCE: The major barriers to accessing surgery from the patients' perspective are the direct and indirect costs of surgery. These can to a large extent be reduced or overcome through the provision of free or low cost surgery at the community level. TRIAL REGISTRATION: ClinicalTrials.gov NCT00522860 and NCT00522912

    Resonant electron transmission through a finite quantum spin chain

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    Electron transport in a finite one dimensional quantum spin chain (with ferromagnetic exchange) is studied within an sds-d exchange Hamiltonian. Spin transfer coefficients strongly depend on the sign of the sds-d exchange constant. For a ferromagnetic coupling, they exhibit a novel resonant pattern, reflecting the salient features of the combined electron-spin system. Spin-flip processes are inelastic and feasible at finite voltage or at finite temperature.Comment: 4 pages including 4 .eps figure

    Near-Infrared Spectroscopy of Molecular Hydrogen Emission in Four Reflection Nebulae: NGC 1333, NGC 2023, NGC 2068, and NGC 7023

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    We present near-infrared spectroscopy of fluorescent molecular hydrogen (H_2) emission from NGC 1333, NGC 2023, NGC 2068, and NGC 7023 and derive the physical properties of the molecular material in these reflection nebulae. Our observations of NGC 2023 and NGC 7023 and the physical parameters we derive for these nebulae are in good agreement with previous studies. Both NGC 1333 and NGC 2068 have no previously-published analysis of near-infrared spectra. Our study reveals that the rotational-vibrational states of molecular hydrogen in NGC 1333 are populated quite differently from NGC 2023 and NGC 7023. We determine that the relatively weak UV field illuminating NGC 1333 is the primary cause of the difference. Further, we find that the density of the emitting material in NGC 1333 is of much lower density, with n ~ 10^2 - 10^4 cm^-3. NGC 2068 has molecular hydrogen line ratios more similar to those of NGC 7023 and NGC 2023. Our model fits to this nebula show that the bright, H_2-emitting material may have a density as high as n ~ 10^5 cm^-3, similar to what we find for NGC 2023 and NGC 7023. Our spectra of NGC 2023 and NGC 7023 show significant changes in both the near-infrared continuum and H_2 intensity along the slit and offsets between the peaks of the H_2 and continuum emission. We find that these brightness changes may correspond to real changes in the density and temperatures of the emitting region, although uncertainties in the total column of emitting material along a given line of sight complicates the interpretation. The spatial difference in the peak of the H_2 and near-infrared continuum peaks in NGC 2023 and NGC 7023 shows that the near-infrared continuum is due to a material which can survive closer to the star than H_2 can.Comment: Submitted for publication in ApJ. 34 pages including 12 embedded postscript figures. Also available at http://www.astronomy.ohio-state.edu/~martini/pub

    Synthetic studies toward the brasilinolides: controlled assembly of a protected C1-C38 polyol based on fragment union by complex aldol reactions.

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    The brasilinolides are an architecturally complex family of 32-membered macrolides, characterised by potent immunosuppressant and antifungal properties, which represent challenging synthetic targets. By adopting a highly convergent strategy, a range of asymmetric aldol/reduction sequences and catalytic protocols were employed to assemble a series of increasingly elaborate fragments. The controlled preparation of suitable C1-C19 and C20-C38 acyclic fragments 5 and 6, containing seven and 12 stereocentres respectively, was first achieved. An adventurous C19-C20 fragment union was then explored to construct the entire carbon chain of the brasilinolides. This pivotal coupling step could be performed in a complex boron-mediated aldol reaction to install the required C19 hydroxyl stereocentre when alternative Mukaiyama-type aldol protocols proved unrewarding. A protected C1-C38 polyol 93 was subsequently prepared, setting the stage for future late-stage diversification toward the various brasilinolide congeners. Throughout this work, asymmetric boron-mediated aldol reactions of chiral ketones with aldehydes proved effective both for controlled fragment assembly and coupling with predictable stereoinduction from the enolate component.We thank the EPSRC (EP/F025734/1) and Syngenta for support, the Isaac Newton–Mays Wild Research Fellowship at Downing College (M.P.H.), the Herchel Smith Postdoctoral Fellowships Fund at Cambridge (C.J.C.) and the Deutsche Akademie der Naturforser Leopoldina (F.A.M.; BMBF-LPD 9901/8-148) for additional funding, and the EPSRC National Mass Spectrometry Centre (Swansea) for mass spectra.This is the final published version of the article. It was originally published in Organic & Biomolecular Chemistry (Paterson I, Housden MP, Cordier CJ, Burton PM, Mühlthau FA, Loiseleur O, Organic & Biomolecular Chemistry, 2015,13, 5716-5733 doi:10.1039/C5OB00498E). The final version is available at http://dx.doi.org/10.1039/C5OB00498

    Absorbable versus silk sutures for surgical treatment of trachomatous trichiasis in Ethiopia: a randomised controlled trial.

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    BACKGROUND: Trachoma causes blindness through an anatomical abnormality called trichiasis (lashes touching the eye). Trichiasis can recur after corrective surgery. We tested the hypothesis that using absorbable sutures instead of silk sutures might reduce the risk of recurrent disease among patients with major trichiasis in a randomised trial. METHODS AND FINDINGS: 1,300 individuals with major trichiasis from rural villages in the Amhara Region of Ethiopia were recruited and assigned (1:1) by computer-generated randomisation sequence to receive trichiasis surgery using either an absorbable suture (polyglactin-910) or silk sutures (removed at 7-10 days) in an otherwise identical surgical technique. Participants were examined every 6 months for 2 years by clinicians masked to allocation. The primary outcome measure was recurrent trichiasis (≥one lash touching the eye) at 1 year. There was no difference in prevalence of recurrent trichiasis at 1 year (114 [18.2%] in the absorbable suture group versus 120 [19.7%] in the silk suture group; odds ratio = 0.90, 95% CI 0.68-1.20). The two groups also did not differ in terms of corneal opacification, visual acuity, conjunctival inflammation, and surgical complications. CONCLUSIONS: There was no evidence that use of absorbable polyglactin-910 sutures was associated with a lower prevalence of trichiasis recurrence at 1 year postsurgery than silk sutures. However, from a programmatic perspective, polyglactin-910 offers the major advantage that patients do not have to be seen soon after surgery for suture removal. The postoperative review after surgery using absorbable polyglactin-910 sutures can be delayed for 3-6 months, which might allow us to better determine whether a patient needs additional surgery. TRIAL REGISTRATION: ClinicalTrials.gov NCT00522860

    Safety and physiological effects of two different doses of elosulfase alfa in patients with morquio a syndrome: A randomized, double-blind, pilot study.

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    The primary treatment outcomes of a phase 2, randomized, double-blind, pilot study evaluating safety, physiological, and pharmacological effects of elosulfase alfa in patients with Morquio A syndrome are herewith presented. Patients aged ≥7 years and able to walk ≥200 m in the 6-min walk test (6MWT) were randomized to elosulfase alfa 2.0 or 4.0 mg/kg/week for 27 weeks. The primary objective was to evaluate the safety of both doses. Secondary objectives were to evaluate effects on endurance (6MWT and 3-min stair climb test [3MSCT]), exercise capacity (cardio-pulmonary exercise test [CPET]), respiratory function, muscle strength, cardiac function, pain, and urine keratan sulfate (uKS) levels, and to determine pharmacokinetic parameters. Twenty-five patients were enrolled (15 randomized to 2.0 mg/kg/week and 10 to 4.0 mg/kg/week). No new or unexpected safety signals were observed. After 24 weeks, there were no improvements versus baseline in the 6MWT, yet numerical improvements were seen in the 3MSCT with 4.0 mg/kg/week. uKS and pharmacokinetic data suggested no linear relationship over the 2.0-4.0 mg/kg dose range. Overall, an abnormal exercise capacity (evaluated in 10 and 5 patients in the 2.0 and 4.0 mg/kg/week groups, respectively), impaired muscle strength, and considerable pain were observed at baseline, and there were trends towards improvements in all domains after treatment. In conclusion, preliminary data of this small study in a Morquio A population with relatively good endurance confirmed the acceptable safety profile of elosulfase alfa and showed a trend of increased exercise capacity and muscle strength and decreased pain

    Nickel versus palladium in cross-coupling catalysis : on the role of substrate coordination to zerovalent metal complexes

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    We report a detailed comparison of the effect of coordinating functional groups on the performance of Suzuki-Miyaura reactions catalysed by nickel and palladium, using competition experiments, robustness screening, and density functional theory calculations. Nickel can interact with a variety of functional groups, which manifests as selectivity in competitive cross-coupling reactions. The presence of these functional groups on exogenous additives has a range of effects on cross-coupling reactions that range from a slight improvement in yield to the complete cessation of the reaction. In contrast, palladium does not interact sufficiently strongly with these functional groups to induce selectivity in cross-coupling reactions; the selectivity of palladium-catalysed cross-coupling reactions is predominantly governed by aryl halide electronic properties
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