168 research outputs found

    Blockchain for and in Logistics: What to Adopt and Where to Start

    Get PDF
    Despite the claim that blockchain will revolutionise business and redefine logistics, existing research so far is limited concerning frameworks that categorise blockchain application potentials and their implications. In particular, academic literature in transport and logistics to date has not sufficiently distinguished between blockchain adoption ('what to adopt') and the identification of the right business opportunity ('where to start'). In response, this paper (1) uses Rogers¿ (2003) 'attributes of innovation framework' to identify potential blockchain applications and (2) presents a framework explicating four transformation phases to subsequently categorise the identified areas of application according to their effects on organisational structures and processes. Using academic and practitioner literature, we classify possible applications for adoption and provide a framework to identify blockchain opportunities in the logistics industry, thereby helping managers to systematically assess where to start building organisational capabilities in order to successfully adopt and deploy blockchain-based technology

    The antecedents, consequences, and mediating role of workload among Chinese courier drivers

    Get PDF
    The growth of e-commerce in China can be regarded as a significant factor in the increase in occupational stress and the voluntary turnover of courier drivers. This paper aims to investigate selected occupational stress factors behind the turnover intentions of Chinese courier drivers. Using data from 229 couriers employed at the largest delivery companies in China, this study applies structural equation modelling to investigate not only the direct relationships between job-stress factors and turnover intentions but also the extent to which workload indirectly mediates turnover intentions among couriers. The results indicate that a combination of high workload with social stressors leads to turnover intentions. In particular, it was found that workload completely mediated the relationship between both the independent variables and the intention to leave the industry, suggesting that when workloads are high, the net effect of negative work experiences with regard to verbal aggression and ambiguous customer expectations increases the likelihood of an intention to leave the industry. Although restricted to China, this is one of the first studies investigating the effects of courier drivers’ job stressors which highlights the importance of delivery companies working with staff to mitigate job stressors to reduce turnover intention

    Classical and Quantum Integrability of 2D Dilaton Gravities in Euclidean space

    Full text link
    Euclidean dilaton gravity in two dimensions is studied exploiting its representation as a complexified first order gravity model. All local classical solutions are obtained. A global discussion reveals that for a given model only a restricted class of topologies is consistent with the metric and the dilaton. A particular case of string motivated Liouville gravity is studied in detail. Path integral quantisation in generic Euclidean dilaton gravity is performed non-perturbatively by analogy to the Minkowskian case.Comment: 27 p., LaTeX, v2: included new refs. and a footnot

    Cyclotron resonance of extremely conductive 2D holes in high Ge content strained heterostructures

    Get PDF
    Cyclotron resonance has been observed in steady and pulsed magnetic fields from high conductivity holes in Ge quantum wells. The resonance positions, splittings and linewidths are compared to calculations of the hole Landau levels

    Critical role of astroglial apolipoprotein E and liver X receptor-α expression for microglial Aβ phagocytosis

    Get PDF
    Liver X receptors (LXRs) regulate immune cell function and cholesterol metabolism, both factors that are critically involved in Alzheimer's disease (AD). To investigate the therapeutic potential of long-term LXR activation in amyloid-β (Aβ) peptide deposition in an AD model, 13-month-old, amyloid plaque-bearing APP23 mice were treated with the LXR agonist TO901317. Postmortem analysis demonstrated that TO901317 efficiently crossed the blood–brain barrier. Insoluble and soluble Aβ levels in the treated APP23 mice were reduced by 80% and 40%, respectively, compared with untreated animals. Amyloid precursor protein (APP) processing, however, was hardly changed by the compound, suggesting that the observed effects were instead mediated by Aβ disposal. Despite the profound effect on Aβ levels, spatial learning in the Morris water maze was only slightly improved by the treatment. ABCA1 (ATP-binding cassette transporter 1) and apolipoprotein E (ApoE) protein levels were increased and found to be primarily localized in astrocytes. Experiments using primary microglia demonstrated that medium derived from primary astrocytes exposed to TO901317 stimulated phagocytosis of fibrillar Aβ. Conditioned medium from TO901317-treated ApoE−/−or LXRα−/−astrocytes did not increase phagocytosis of Aβ. In APP23 mice, long-term treatment with TO901317 strongly increased the association of microglia and Aβ plaques. Short-term treatment of APP/PS1 mice with TO901317 also increased this association, which was dependent on the presence of LXRα and was accompanied by increased ApoE lipidation. Together, these data suggest that astrocytic LXRα activation and subsequent release of ApoE by astrocytes is critical for the ability of microglia to remove fibrillar Aβ in response to treatment with TO901317.</jats:p

    A Large Web-Based Observer Reliability Study of Early Ischaemic Signs on Computed Tomography. The Acute Cerebral CT Evaluation of Stroke Study (ACCESS)

    Get PDF
    BACKGROUND: Early signs of ischaemic stroke on computerised tomography (CT) scanning are subtle but CT is the most widely available diagnostic test for stroke. Scoring methods that code for the extent of brain ischaemia may improve stroke diagnosis and quantification of the impact of ischaemia. METHODOLOGY AND PRINCIPAL FINDINGS: We showed CT scans from patients with acute ischaemic stroke (n = 32, with different patient characteristics and ischaemia signs) to doctors in stroke-related specialties world-wide over the web. CT scans were shown twice, randomly and blindly. Observers entered their scan readings, including early ischaemic signs by three scoring methods, into the web database. We compared observers' scorings to a reference standard neuroradiologist using area under receiver operator characteristic curve (AUC) analysis, Cronbach's alpha and logistic regression to determine the effect of scales, patient, scan and observer variables on detection of early ischaemic changes. Amongst 258 readers representing 33 nationalities and six specialties, the AUCs comparing readers with the reference standard detection of ischaemic signs were similar for all scales and both occasions. Being a neuroradiologist, slower scan reading, more pronounced ischaemic signs and later time to CT all improved detection of early ischaemic signs and agreement on the rating scales. Scan quality, stroke severity and number of years of training did not affect agreement. CONCLUSIONS: Large-scale observer reliability studies are possible using web-based tools and inform routine practice. Slower scan reading and use of CT infarct rating scales improve detection of acute ischaemic signs and should be encouraged to improve stroke diagnosis

    Thirty-two Goldbach Variations

    Full text link
    We give thirty-two diverse proofs of a small mathematical gem--the fundamental Euler sum identity zeta(2,1)=zeta(3) =8zeta(\bar 2,1). We also discuss various generalizations for multiple harmonic (Euler) sums and some of their many connections, thereby illustrating both the wide variety of techniques fruitfully used to study such sums and the attraction of their study.Comment: v1: 34 pages AMSLaTeX. v2: 41 pages AMSLaTeX. New introductory material added and material on inequalities, Hilbert matrix and Witten zeta functions. Errors in the second section on Complex Line Integrals are corrected. To appear in International Journal of Number Theory. Title change

    Quantum dilaton gravity as a linear dilaton conformal field theory

    Get PDF
    A model of matter-coupled gravity in two dimensions is quantized. The crucial requirement for performing the quantization is the vanishing of the conformal anomaly, which is achieved by tuning a parameter in the interaction potential. The spectrum of the theory is determined by mapping the model first onto a field theory with a Liouville interaction, then onto a linear dilaton conformal field theory. In absence of matter fields a pure gauge theory with massless ground state is found; otherwise it is possible to minimally couple up to 11 matter scalar fields: in this case the ground state is tachyonic and the matter sector decouples, like the transverse oscillators in the critical bosonic string.Comment: 7 pages, RevTeX4 file. v2: some comments and one reference adde

    Extent of hypoattenuation on CT angiography source images in Basilar Artery occlusion: prognostic value in the Basilar Artery International Cooperation Study

    Get PDF
    &lt;p&gt;&lt;b&gt;Background and Purpose:&lt;/b&gt; The posterior circulation Acute Stroke Prognosis Early CT Score (pc-ASPECTS) quantifies the extent of early ischemic changes in the posterior circulation with a 10-point grading system. We hypothesized that pc-ASPECTS applied to CT angiography source images predicts functional outcome of patients in the Basilar Artery International Cooperation Study (BASICS).&lt;/p&gt; &lt;p&gt;&lt;b&gt;Methods:&lt;/b&gt; BASICS was a prospective, observational registry of consecutive patients with acute symptomatic basilar artery occlusion. Functional outcome was assessed at 1 month. We applied pc-ASPECTS to CT angiography source images of patients with CT angiography for confirmation of basilar artery occlusion. We calculated unadjusted and adjusted risk ratios (RRs) of pc-ASPECTS dichotomized at &#8805;8 versus &#60;8. Primary outcome measure was favorable outcome (modified Rankin Scale scores 0–3). Secondary outcome measures were mortality and functional independence (modified Rankin Scale scores 0–2).&lt;/p&gt; &lt;p&gt;&lt;b&gt;Results:&lt;/b&gt; Of 158 patients included, 78 patients had a CT angiography source images pc-ASPECTS ≥8. Patients with a pc-ASPECTS ≥8 more often had a favorable outcome than patients with a pc-ASPECTS &#60;8 (crude RR, 1.7; 95% CI, 0.98–3.0). After adjustment for age, baseline National Institutes of Health Stroke Scale score, and thrombolysis, pc-ASPECTS &#8805;8 was not related to favorable outcome (RR, 1.3; 95% CI, 0.8–2.2), but it was related to reduced mortality (RR, 0.7; 95% CI, 0.5–0.98) and functional independence (RR, 2.0; 95% CI, 1.1–3.8). In post hoc analysis, pc-ASPECTS dichotomized at &#8805;6 versus &#60;6 predicted a favorable outcome (adjusted RR, 3.1; 95% CI, 1.2–7.5).&lt;/p&gt; &lt;p&gt;&lt;b&gt;Conclusions:&lt;/b&gt; pc-ASPECTS on CT angiography source images independently predicted death and functional independence at 1 month in the CT angiography subgroup of patients in the BASICS registry.&lt;/p&gt

    Testing of a Wireless Sensor System for Instrumented Thermal Protection Systems

    Get PDF
    Funded by NASA's Constellation Universities Institutes Project (CUIP), we have been developing and testing a system to wirelessly power and collect data from sensors on space platforms in general and, in particular, the harsh environment of spacecraft re-entry. The elimination of wires and associated failures such as chafing, sparking, ageing, and connector issues can increase reliability and design flexibility while reducing costs. These factors present an appealing case for the pursuit of wireless solutions for harsh environments, particularly for their use in space and on spacecraft. We have designed and built a prototype wireless sensor system. The system, with capabilities similar to that of a wired sensor system, was tested in NASA Ames Research Center s Aerodynamic Heating Facility and Interaction Heating Facility. This paper discusses the overall development effort, testing results, as well as future directions
    corecore