1,404 research outputs found

    Process study of the formation of biodegradable polymer microspheres for tissue engineering

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    A series of polymer microspheres was prepared via solvent evaporation by dispersing dichloromethane solutions of polylactic-co-glycolic acid (PLGA) in water. The dimensions of the final dry particles were measured by laser diffraction and correlated to the main fluid-dynamic parameters of the dispersion process, namely viscosity ratio, volume fraction of dispersed phase, intensity of stirring, and Weber number (We). Data analysis indicated that the system under study can be quantitatively well described by empirical models present in the literature and concerning the dispersion of liquid-liquid immiscible systems. The PLGA microspheres obtained in this way may be employed for fabrication of biodegradable scaffolds for tissue engineering

    The determinants of university strategic positioning: A reappraisal of the organizational dimension

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    This paper makes a contribution to the debate on university organisational actorhood by theorising the determinants of institutional strategic positioning. It argues that besides environmental forces and managerial rationality, the organisational dimension needs to be accounted for. Addressing the mixed empirical evidence in the relevant literature, we conceptualise the organisational dimension as a meso-level intervening variable mediating both external influences (outside-inside) and organisational action (inside-outside). We operationalize the organizational dimension along three components: organizational structure, identity, and centrality, which are further elaborated in sub-components and indicators. A set of hypotheses to be tested in empirical research is provided. The paper offers new perspectives on the dynamics of change in higher education and on strategic agency of organizational actors

    The role of the organisational dimension in university positioning: a case-study approach

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    This paper argues that university strategic positioning is influenced by the organisational dimension, operationalised along the variables of organisational structure, identity and centrality. A comparative case study is presented including two English and two Italian universities and drawing on a set of sixty interviews with academic leaders, managers and administrators. The analysis of the trajectory of the four universities from 2004 to 2018 illustrates the articulation of the link between the three organisational variables and positioning and how this has changed over time. Finally, the paper outlines six propositions on the expected impact of the organisational structure, identity and centrality on positioning processes of universities

    The determinants of university strategic positioning: a reappraisal of the organisation

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    This paper makes a contribution to the debate on university organisational actorhood by theorising the determinants of institutional strategic positioning. It argues that besides environmental forces and managerial rationality, the organisational dimension needs to be accounted for. Addressing the mixed empirical evidence in the relevant literature, we conceptualise the organisational dimension as a meso-level intervening variable mediating both external influences (outside-inside) and organisational action (inside-outside). We operationalise the organisational dimension along three components: organisational structure, identity and centrality, which are further elaborated in sub-components and indicators. A set of hypotheses to be tested in empirical research is provided. The paper offers new perspectives on the dynamics of change in higher education and on strategic agency of organisational actors

    Towards Precision Photometry with Extremely Large Telescopes: the Double Subgiant Branch of NGC 1851

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    The Extremely Large Telescopes currently under construction have a collecting area that is an order of magnitude larger than the present largest optical telescopes. For seeing-limited observations the performance will scale as the collecting area but, with the successful use of adaptive optics, for many applications it will scale as D4D^4 (where DD is the diameter of the primary mirror). Central to the success of the ELTs, therefore, is the successful use of multi-conjugate adaptive optics (MCAO) that applies a high degree correction over a field of view larger than the few arcseconds that limits classical adaptive optics systems. In this letter, we report on the analysis of crowded field images taken on the central region of the Galactic globular cluster NGC 1851 in KsK_s band using GeMS at the Gemini South telescope, the only science-grade MCAO system in operation. We use this cluster as a benchmark to verify the ability to achieve precise near-infrared photometry by presenting the deepest KsK_s photometry in crowded fields ever obtained from the ground. We construct a colour-magnitude diagram in combination with the F606W band from HST/ACS. As well as detecting the "knee" in the lower main sequence at Ks≃20.5K_s\simeq20.5, we also detect the double subgiant branch of NGC 1851, that demonstrates the high photometric accuracy of GeMS in crowded fields.Comment: Accepted for publication in ApJL (3 Sep 2015). A version of the paper with high-res images is available at http://www.astro.uvic.ca/~alan/ms_arxiv_hr.pd

    Time-dependent photoionization of azulene: Competition between ionization and relaxation in highly excited states

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    Pump-probe photoionization has been used to map the relaxation processes taking place from highly vibrationally excited levels of the S2 state of azulene, populated directly or via internal conversion from the S4 state. Photoelectron spectra obtained by 1+2’ two-color time-resolved photoelectron imaging are invariant (apart from in intensity) to the pump-probe time delay and to pump wavelength. This reveals a photoionization process which is driven by an unstable electronic state (e.g. doubly excited state) lying below the ionization potential. This state is postulated to be populated by a probe transition from S2 and to rapidly relax via an Auger like process onto highly vibrationally excited Rydberg states. This accounts for the time invariance of the photoelectron spectrum. The intensity of the photoelectron spectrum is proportional to the population in S2. An exponential energy gap law is used to describe the internal conversion rate from S2 to S0. The vibronic coupling strength is found to be larger than 60±5 ÎŒeV

    Molecular Biomarkers in Sinonasal Cancers: New Frontiers in Diagnosis and Treatment

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    Purpose of Review: Sinonasal tumors are rare and heterogeneous diseases which pose challenges in diagnosis and treatment. Despite significant progress made in surgical, oncological, and radiotherapy fields, their prognosis still remains poor. Therefore, alternative strategies should be studied in order to refine diagnosis and improve patient care. Recent Findings: In recent years, in-depth molecular studies have identified new biological markers, such as genetic abnormalities and epigenetic variations, which have allowed to refine diagnosis and predict prognosis. As a consequence, new histological entities have been described and specific subgroup stratifications within the well-known histotypes have been made possible. These discoveries have expanded indications for immunotherapy and targeted therapies in order to reduce tumor spread, thus representing a valuable implementation of standard treatments. Summary: Recent findings in molecular biology have paved the way for better understanding and managing such rare and aggressive tumors. Although further efforts need to be made in this direction, expectations are promising

    Astrometry with MCAO: HST-GeMS proper motions in the globular cluster NGC 6681

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    Aims: for the first time the astrometric capabilities of the Multi-Conjugate Adaptive Optics (MCAO) facility GeMS with the GSAOI camera on Gemini-South are tested to quantify the accuracy in determining stellar proper motions in the Galactic globular cluster NGC 6681. Methods: proper motions from HST/ACS for a sample of its stars are already available, and this allows us to construct a distortion-free reference at the epoch of GeMS observations that is used to measure and correct the temporally changing distortions for each GeMS exposure. In this way, we are able to compare the corrected GeMS images with a first-epoch of HST/ACS images to recover the relative proper motion of the Sagittarius dwarf spheroidal galaxy with respect to NGC 6681. Results: we find this to be (\mu_{\alpha}cos\delta, \mu_{\delta}) = (4.09,-3.41) mas/yr, which matches previous HST/ACS measurements with a very good accuracy of 0.03 mas/yr and with a comparable precision (r.m.s of 0.43 mas/yr). Conclusions: this study successfully demonstrates that high-quality proper motions can be measured for quite large fields of view (85 arcsec X 85 arcsec) with MCAO-assisted, ground-based cameras and provides a first, successful test of the performances of GeMS on multi-epoch data.Comment: 5 pages, 4 figures. Accepted for publication by A&A Letter

    Is merit pay changing ethos in public administration?

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    This article aims to explore the changes in the organizational culture of public administrations following the implementation of performance-related pay\u2014 PRP systems. The work explores the switch to an explicit remuneration system through the implementation of incentives and focuses on the effects, positive or negative, this has had on the ethos of public administrations. Data from a survey carried out among private and public employees in a specific area of Southern Italy are used to analyze how the shift from an implicit to an explicit remuneration system has impacted the public servants\u2019 ethos. Due to the application of PRP, public servants are now expected to be compensated based on their performance. The ineffective management of incentives in public administrations affects the intrinsic motivation of public employees and may lead to moral disengagement. While the previous literature has focused on the practical challenges and limitations of PRP, less has been written about how PRP has changed the culture of public administrations. This article shows how PRP can change the traditional ethos ofpublic administrations\u2019 services based on the Weberian model of bureaucracy, replacing the latter with a new on

    Bibliometric analysis as mesaure [sic] of long-term performance in pancreatic cancer research.

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    Introduction: Research on pancreatic cancer consists in basic, translational and clinical research. Bibliometric indexes as IF and H-Index have been proposed as measures of quality and performance for medical research. Our goal was to analyze the IF and the 5-years H-Index of the publications about pancreatic cancer research
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