867 research outputs found

    Laser driven self-assembly of shape-controlled potassium nanoparticles in porous glass

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    We observe growth of shape-controlled potassium nanoparticles inside a random network of glass nanopores, exposed to low-power laser radiation. Visible laser light plays a dual role: it increases the desorption probability of potassium atoms from the inner glass walls and induces the self-assembly of metastable metallic nanoparticles along the nanopores. By probing the sample transparency and the atomic light-induced desorption flux into the vapour phase, the dynamics of both cluster formation/evaporation and atomic photo-desorption processes are characterized. Results indicate that laser light not only increases the number of nanoparticles embedded in the glass matrix but also influences their structural properties. By properly choosing the laser frequency and the illumination time, we demonstrate that it is possible to tailor the nanoparticles'shape distribution. Furthermore, a deep connection between the macroscopic behaviour of atomic desorption and light-assisted cluster formation is observed. Our results suggest new perspectives for the study of atom/surface interaction as well as an effective tool for the light-controlled reversible growth of nanostructures.Comment: 14 pages,6 figures, http://iopscience.iop.org/1612-202X/11/8/085902

    Navigating a global pandemic crisis through marketing agility: evidence from Italian B2B firms

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    Purpose This study aims to explore the impact of marketing agility on the business-to-business (B2B) firms' capacity to address unexpected events such as the recent coronavirus (COVID-19) pandemic, examining how they reshape their strategies during the different stages of a crisis. Design/methodology/approach This study follows a theory-building approach and performs an in-depth exploratory multiple-case study in the context of 16 Italian firms operating in the B2B sector. Findings The study develops an event-sequence-based framework and illustrates how agile marketing strategies empower B2B firms to cope with a crisis across three crucial moments: the event phase, the response management phase and the investigation phase. Originality/value This paper contributes to a better understanding of marketing agility in the context of crisis management by showing the agile marketing strategies that B2B firms adopt during the different stages of a crisis. This work provides a useful foundation to assist managers in coping with market uncertainty. It suggests practical guidelines to make more informed strategic and operational marketing decisions, increasing a firm's capacity to act in today's fast-moving, complex times

    A room-temperature alternating current susceptometer - Data analysis, calibration, and test

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    An AC susceptometer operating in the range of 10 Hz to 100 kHz and at room temperature is designed, built, calibrated and used to characterize the magnetic behaviour of coated magnetic nanoparticles. Other weakly magnetic materials (in amounts of some millilitres) can be analyzed as well. The setup makes use of a DAQ-based acquisition system in order to determine the amplitude and the phase of the sample magnetization as a function of the frequency of the driving magnetic field, which is powered by a digital waveform generator. A specific acquisition strategy makes the response directly proportional to the sample susceptibility, taking advantage of the differential nature of the coil assembly. A calibration method based on conductive samples is developed.Comment: 8 pages, 7 figures, 19 ref

    Long-term outcomes in corticosteroid-refractory Graves' orbitopathy treated with tocilizumab.

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    Up to 20% of patients with moderate to severe Graves' orbitopathy (GO) do not respond to high-dose glucocorticoids (GC). A few studies, including a randomized trial, have demonstrated the efficacy of interleukin-6 (IL-6) blockade with tocilizumab (TCZ) in GC-refractory GO. However, data on predictors of response to TCZ and long-term outcomes are lacking. Observational single-center study on ten consecutive patients treated with TCZ for GC-refractory GO, between 2016 and 2020. Median (interquartile range) follow-up was 24 (12-36) months. Inflammation and exophthalmos improved dramatically in all patients within months after starting TCZ. Mean Clinical Activity Score decreased from 4.80 ± 1.13 to 0.70 ± 0.82 points at 6 months (mean change: -4.10 ± 1.52; p < .0001). Proptosis improved from 23.2 ± 2.1 to 20.6 ± 2.0 mm at 6 months (mean change: -2.9 ± 1.4 mm; p < .0001). Diplopia resolved in 7 patients. Thyroid receptor antibodies decreased markedly during TCZ treatment. Baseline serum IL-6 levels did not predict clinical response. TCZ was well-tolerated. During follow-up, 3 patients were diagnosed with cancer (breast cancer in 2 and urothelial cancer in 1). TCZ was rapidly effective and well-tolerated in our patients with GC-refractory GO. Four patients experienced mild/moderate adverse events as neutropenia, hyperlipidemia, and infections; nearly a third developed cancer during the follow-up. The increased incidence observed could be explained by the high prevalence of smokers, that are at higher risk for Graves' orbitopathy and solid malignancies as breast cancer. Thus, regular cancer screening could be proposed to this vulnerable population receiving high doses of immunosuppressants

    Disentangling the corporate entrepreneurship construct: conceptualizing through co-words

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    This study defines the conceptual structure of corporate entrepreneurship (CE) by looking at the terms scholars have used over the last 26 years of research. With the use of a co-word analysis, five distinctive dimensions of CE and the evolution of related key terms are identified: sustained regeneration, competitive advantage, external entrepreneurship, organizational rejuvenation, and domain redefinition. Over time scholars’ attention has shifted from strategy to entrepreneurship by highlighting the relevance of the terms ‘intrapreneurship’ and ‘entrepreneurial orientation’. Surprisingly, concepts related to strategic entrepreneurship and strategic renewal are less relevant than expected. Besides laying the ground for a shared conceptualization of CE, this study highlights how bibliomeitrics can contribute to decreasing conceptual ambiguity in emergent research fields, such as entrepreneurship. Implications for managers on how to strategically create and develop CE within different organizational settings are also discussed

    Larmor frequency dressing by an anharmonic transverse magnetic field

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    We present a theoretical and experimental study of spin precession in the presence of both a static and an orthogonal oscillating magnetic field, which is nonresonant, not harmonically related to the Larmor precession, and of arbitrary strength. Due to the intrinsic nonlinearity of the system, previous models that account only for the simple sinusoidal case cannot be applied. We suggest an alternative approach and develop a model that closely agrees with experimental data produced by an optical-pumping atomic magnetometer. We demonstrate that an appropriately designed nonharmonic field makes it possible to extract a linear response to a weak dc transverse field, despite the scalar nature of the magnetometer, which normally causes a much weaker, second-order response.Comment: Published version has some minor changes; 22 pages and 8 picture

    A new class of sum rules for products of Bessel functions

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    In this paper we derive a new class of sum rules for products of the Bessel functions of first kind. Using standard algebraic manipulations we extend some of the well known properties of JnJ_n. Some physical applications of the results are also discussed. A comparison with the Newberger[J. Math. Phys. \textbf{23} (1982) 1278] sum rules is performed on a typical example.Comment: Published in Journal of Mathematical Physics, 9 pages, no picture

    Stroboscopic Laser Diagnostics for Detection of Ordering in One-Dimensional Ion beam

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    A novel diagnostic method for detecting ordering in one-dimensional ion beams is presented. The ions are excited by a pulsed laser at two different positions along the beam and fluorescence is observed by a group of four photomultipliers. Correlation in fluorescence signals is firm indication that the ion beam has an ordered structure.Comment: 7 pages, REVTEX, fig3 uuencoded, figs 1-2 available upon request from [email protected], to appear in Phys. Rev.

    Improved and standardized method for assessing years lived with disability after burns and its application to estimate the non-fatal burden of disease of burn injuries in Australia, New Zealand and the Netherlands

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    Background: Burden of disease estimates are an important resource in public health. Currently, robust estimates are not available for the burn population. Our objectives are to adapt a refined methodology (INTEGRIS method) to burns and to apply this new INTEGRIS-burns method to estimate, and compare, the burden of disease of burn injuries in Australia, New Zealand and the Netherlands. Methods: Existing European and Western-Australian health-related quality of life (HRQL) datasets were combined to derive disability weights for three homogenous burn injury groups based on percentage total body surface area (%TBSA) burned. Subsequently, incidence data from Australia, New Zealand, and the Netherlands from 2010 to 2017 were used to compute annual non-fatal burden of disease estimates for each of these three countries. Non-fatal burden of disease was measured by years lived with disability (YLD). Results: The combined dataset included 7159 HRQL (EQ-5D-3 L) outcomes from 3401 patients. Disability weights ranged from 0.046 (subgroup  24 months post-burn) to 0.497 (subgroup > 20% TBSA burned 0–1 months post-burn). In 2017 the non-fatal burden of disease of burns for the three countries (YLDs/100,000 inhabitants) was 281 for Australia, 279 for New Zealand and 133 for the Netherlands. Conclusions: This project established a method for more precise estimates of the YLDs of burns, as it is the only method adapted to the nature of burn injuries and their recovery. Compared to previous used methods, the INTEGRIS-burns method includes improved disability weights based on severity categorization of burn patients; a better substantiated proportion of patients with lifelong disability based; and, the application of burn specific recovery timeframes. Information derived from the adapted method can be used as input for health decision making at both the national and international level. Future studies should investigate whether the application is valid in low- and middle- income countries
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