4,011 research outputs found
New insights into the internationalization of producer services:Organizational strategies and spatial economies for global headhunting firms
This paper uses the exemplar of global headhunting firms to provide new insights into the intricacies of internationalization and related âspatial economiesâ of producer services in the world economy. In particular, we unpack the complex relationships between the organisational rationale for, the selected mode of, and future benefits gained by internationalization, as headhunting firms seek and create new geographical markets. We achieve this through an analysis of headhunting firm-specific case study data that details the evolving way such firms organize their differential strategic growth (organic, merger and acquisition, and alliances/network) and forms (wholly-owned, networked or hybrid). We also highlight how, as elite labour market intermediaries, headhunters are important, yet understudied, actors within the (re)production of a âsofterâ, âknowledgeableâ capitalism. Our argument, exemplified through detailed mapping of the changing geographies of headhunting firms between 1992 and 2005, demonstrates the need for complex and blurred typologies of internationalization and similarly complex internationalization theory
Isolating quantum coherence with pathway-selective coherent multi-dimensional spectroscopy
Coherent coupling between spatially separated systems has long been explored
as a necessary requirement for quantum information and cryptography. Recent
discoveries suggest such phenomena appear in a much wider range of processes,
including light-harvesting in photosynthesis. These discoveries have been
facilitated by developments in coherent multi-dimensional spectroscopy (CMDS)
that allow interactions between different electronic states to be identified in
crowded spectra. For complex systems, however, spectral broadening and multiple
overlapping peaks limit the ability to separate, identify and properly analyse
all contributions. Here we demonstrate how pathway-selective CMDS can overcome
these limitations to reveal, isolate and allow detailed analysis of weak
coherent coupling between spatially separated excitons localised to different
semiconductor quantum wells. Selective excitation of the coherence pathways, by
spectrally shaping the laser pulses, provides access to previously hidden
details and enables quantitative analysis that can facilitate precise and
detailed understanding of interactions in this and other complex systems
Table of Contents and Prologue
Editorial board, Table of contents, and Prologue, an introduction to volume
The Aims of the Criminal Law
Cu2ZnSnS4(CZTS) is an interesting material for sustainable photovoltaics, but efficiencies are limitedby the low open-circuit voltage. A possible cause of this is disorder among the Cu and Zn cations, aphenomenon which is difficult to detect by standard techniques. We show that this issue can beovercome using near-resonant Raman scattering, which lets us estimate a critical temperature of 533±10 K for the transition between ordered and disordered CZTS. These findings have deepsignificance for the synthesis of high-quality material, and pave the way for quantitative investigationof the impact of disorder on the performance of CZTS-based solar cells.kestCa
Robust control design with real parameter uncertainty using absolute stability theory
The purpose of this thesis is to investigate an extension of mu theory for robust control design by considering systems with linear and nonlinear real parameter uncertainties. In the process, explicit connections are made between mixed mu and absolute stability theory. In particular, it is shown that the upper bounds for mixed mu are a generalization of results from absolute stability theory. Both state space and frequency domain criteria are developed for several nonlinearities and stability multipliers using the wealth of literature on absolute stability theory and the concepts of supply rates and storage functions. The state space conditions are expressed in terms of Riccati equations and parameter-dependent Lyapunov functions. For controller synthesis, these stability conditions are used to form an overbound of the H2 performance objective. A geometric interpretation of the equivalent frequency domain criteria in terms of off-axis circles clarifies the important role of the multiplier and shows that both the magnitude and phase of the uncertainty are considered. A numerical algorithm is developed to design robust controllers that minimize the bound on an H2 cost functional and satisfy an analysis test based on the Popov stability multiplier. The controller and multiplier coefficients are optimized simultaneously, which avoids the iteration and curve-fitting procedures required by the D-K procedure of mu synthesis. Several benchmark problems and experiments on the Middeck Active Control Experiment at M.I.T. demonstrate that these controllers achieve good robust performance and guaranteed stability bounds
Geological aspects of Banda Sea ecosystems and how they shape the oceanographical profile
The Banda Sea is a collage of young oceanic basins and fragmented Australian continental crust located at the heart of the Australia-SE Asia collision zone where Australian and Asian biogeographic regions converge. The formation of the sea was governed by the southeastward rollback of the Banda Slab since c. 16 Ma, which in its wake opened new oceanic basins and extended and fragmented Australian crust. These Australian crustal fragments are today either stranded within the Banda Sea where they form the prominent submarine 'Banda Ridges', or now reside as thrust-sheets on the NW Australian shelf after being transported all the way to the southern Banda Arc. The deepest part of the Banda Sea, the 7.2 km Weber Deep, was formed by extreme lithospheric extension that occured in the latter stages of Banda Slab rollback. This extension was accommodated by the vast low-angle 'Banda Detachment', which operated above the subducted fringes of the Australian continental margin
Predicting the whispering gallery mode spectra of microresonators
The whispering gallery modes (WGMs) of optical resonators have prompted
intensive research efforts due to their usefulness in the field of biological
sensing, and their employment in nonlinear optics. While much information is
available in the literature on numerical modeling of WGMs in microspheres, it
remains a challenging task to be able to predict the emitted spectra of
spherical microresonators. Here, we establish a customizable Finite- Difference
Time-Domain (FDTD)-based approach to investigate the WGM spectrum of
microspheres. The simulations are carried out in the vicinity of a dipole
source rather than a typical plane-wave beam excitation, thus providing an
effective analogue of the fluorescent dye or nanoparticle coatings used in
experiment. The analysis of a single dipole source at different positions on
the surface or inside a microsphere, serves to assess the relative efficiency
of nearby radiating TE and TM modes, characterizing the profile of the
spectrum. By varying the number, positions and alignments of the dipole
sources, different excitation scenarios can be compared to analytic models, and
to experimental results. The energy flux is collected via a nearby disk-shaped
region. The resultant spectral profile shows a dependence on the configuration
of the dipole sources. The power outcoupling can then be optimized for specific
modes and wavelength regions. The development of such a computational tool can
aid the preparation of optical sensors prior to fabrication, by preselecting
desired the optical properties of the resonator.Comment: Approved version for SPIE Photonics West, LASE, Laser Resonators,
Microresonators and Beam Control XV
Method for predicting whispering gallery mode spectra of spherical microresonators
A full three-dimensional Finite-Difference Time-Domain (FDTD)-based toolkit
is developed to simulate the whispering gallery modes of a microsphere in the
vicinity of a dipole source. This provides a guide for experiments that rely on
efficient coupling to the modes of microspheres. The resultant spectra are
compared to those of analytic models used in the field. In contrast to the
analytic models, the FDTD method is able to collect flux from a variety of
possible collection regions, such as a disk-shaped region. The customizability
of the technique allows one to consider a variety of mode excitation scenarios,
which are particularly useful for investigating novel properties of optical
resonators, and are valuable in assessing the viability of a resonator for
biosensing.Comment: Published 10 Apr 2015 in Opt. Express Vol. 23, Issue 8, pp.
9924-9937; The FDTD toolkit supercomputer scripts are hosted at:
http://sourceforge.net/projects/npps/files/FDTD_WGM_Simulator
Scholarly Activity in Residency: A Needs Assessment of Challenges and Proposed Solutions
Introduction
Resident physician participation in scholarly activity is associated with significant benefits ranging from traineesâ personal development to improved quality of patient care. Residency programs have taken varied approaches to improve resident engagement in scholarship, though interventions have demonstrated mixed results regarding objective measures of scholarly productivity. Concerns regarding waining interest in scholarship amongst internal medicine residents prompted a department-wide needs assessment to evaluate opportunities for scholarship and challenges preventing resident participation.
Methods
A web-based survey was developed and distributed to Department of Internal Medicine faculty and residents at the PGY2 level or higher and recent graduates within the last year prior to the study. We investigated perceived opportunities for resident scholarship, perceived challenges with resident scholarly activity, preferences regarding scholarly projects, and faculty experiences with mentorship. Descrptive statistics were used to describe survey responses.
Results
Faculty and trainees shared similar perceptions of inadequate opportunities for resident participation in scholarly activity and endorsed a preference to join ongoing projects early in their course as opposed to starting new projects or joining projects near their completion. Both groups identified lack of resident time as a barrier to resident participation in scholarly activity but faculty were more likely to report lack of resident aptitude for research and lack of faculty time and aptitude for mentorship as challenges.
Conclusions
Residents and faculty are not aware of all the resources in place to support scholarship opportunities for trainees. Resident and faculty time is a significant barrier to resident scholarship and further efforts are needed to support faculty and trainee collaboration while mitigating challenges which limit the use of currently available resources. Regular curricular assessment is necessary to ensure that trainees and faculty are aware of available resources and that those resources are meeting the departments specific needs
Co-designed Land-use Scenarios and their Implications for Storm Runoff and Streamflow in New England
Landscape and climate changes have the potential to create or exacerbate problems with stormwater management, high flows, and flooding. In New England, four plausible land-use scenarios were co-developed with stakeholders to give insight to the effects on ecosystem services of different trajectories of socio-economic connectedness and natural resource innovation. With respect to water, the service of greatest interest to New England stakeholders is the reduction of stormwater and flooding. To assess the effects of these land-use scenarios, we applied the Soil and Water Assessment Tool to two watersheds under two climates. Differences in land use had minimal effects on the water balance but did affect high flows and the contribution of storm runoff to streamflow. For most scenarios, the effect on high flows was small. For one scenarioâenvisioned to have global socio-economic connectedness and low levels of natural resource innovationâgrowth in impervious areas increased the annual maximum daily flow by 10%, similar to the 5â15% increase attributable to climate change. Under modest population growth, land-use decisions have little effect on storm runoff and high flows; however, for the two scenarios characterized by global socio-economic connectedness, differences in choices regarding land use and impervious area have a large impact on the potential for flooding. Results also indicate a potential interaction between climate and land use with a shift to more high flows resulting from heavy rains than from snowmelt. These results can help inform land use and development, especially when combined with assessments of effects on other ecosystem services
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