1,442 research outputs found
Process study of the formation of biodegradable polymer microspheres for tissue engineering
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
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
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
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
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 (where 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 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 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
, 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
Molecular Biomarkers in Sinonasal Cancers: New Frontiers in Diagnosis and Treatment
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
Time-dependent photoionization of azulene: Competition between ionization and relaxation in highly excited states
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+2â 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 ΌeV
Astrometry with MCAO: HST-GeMS proper motions in the globular cluster NGC 6681
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?
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.
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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