504 research outputs found
Looking for Guidance? Five Principles for Leveraging Tensions in CorporateâStartup Collaboration
Corporateâstartup collaboration (CSC) allows the co-development of innovations for pressing societal needs. Paradoxically, CSC is both fueled and challenged by diverging interests and approaches of the unequal actors. We apply a paradox lens to better understand the complex collaborative demands of CSC from the perspective of the corporate actors involved. Over the course of three years, we conducted 52 contextualized semi-structured interviews in a corporate-sponsored accelerator pursuing sustainability improvements. We identify five CSC paradoxes, which we translate into guiding principles for managing such paradoxes with a both/and mindset. Further, we show how these guiding principles help to address interdependencies between the CSC paradoxes. By disentangling the inherently paradoxical nature of the collaborative demands, we contribute to a fuller theoretical understanding of how organizational actors can manage these demands. We encourage companies engaging in CSC to use the guiding principles for empowering organizational actorsâ understanding and approaches to CSC paradoxes
The bicycle-train travellers in the Netherlands: personal profiles and travel choices
The Netherlands seems to exhibit the unique conditions that allow cycling on the country level instead of only the city level. Moreover, the national transit system seemingly provides one crucial condition: citizens use the train and cycling systems in an integrated manner, with combined bicycle-train transport recently demonstrating strong growth. Relatively little is known about bicycle-train users, i.e. the people who combine the bicycle and the train in a single trip. In this paper, we investigate their profiles and travel choices, in terms of the modes they choose for access and egress travel, their choice of stations, and their choice of type of bicycles. Studying this specific group can add to our understanding of the role of the train system in the success of cycling in the Netherlands, in turn helping improve policy transfer to metropolitan areas in other countries. In 2017, in cooperation with the Dutch National Railways, researchers surveyed a sample of train travellers, ultimately resulting in more than 3000 completed questionnaires. Descriptive analyses revealed that, compared to train travellers who do not or rarely cycle to/from train stations, bicycle-train users are on average more likely to be young people who are engaged in full-time employment or entrepreneurs, commute to work and hold university degrees. As for their cycling behaviour, bicycle-train travellers use bicycles much more often on the home-end of train trips than on the activity-end. Furthermore, bicycle-train travellers infrequently use suburban stations on the home-end, preferring large stations in the centres of major cities instead. For those who use bicycles, shared bicycles claim a considerable share on the activity-end of a train trip
Monte Carlo study of the hull distribution for the q=1 Brauer model
We study a special case of the Brauer model in which every path of the model
has weight q=1. The model has been studied before as a solvable lattice model
and can be viewed as a Lorentz lattice gas. The paths of the model are also
called self-avoiding trails. We consider the model in a triangle with boundary
conditions such that one of the trails must cross the triangle from a corner to
the opposite side. Motivated by similarities between this model, SLE(6) and
critical percolation, we investigate the distribution of the hull generated by
this trail (the set of points on or surrounded by the trail) up to the hitting
time of the side of the triangle opposite the starting point. Our Monte Carlo
results are consistent with the hypothesis that for system size tending to
infinity, the hull distribution is the same as that of a Brownian motion with
perpendicular reflection on the boundary.Comment: 21 pages, 9 figure
Exact sampling of self-avoiding paths via discrete Schramm-Loewner evolution
We present an algorithm, based on the iteration of conformal maps, that
produces independent samples of self-avoiding paths in the plane. It is a
discrete process approximating radial Schramm-Loewner evolution growing to
infinity. We focus on the problem of reproducing the parametrization
corresponding to that of lattice models, namely self-avoiding walks on the
lattice, and we propose a strategy that gives rise to discrete paths where
consecutive points lie an approximately constant distance apart from each
other. This new method allows us to tackle two non-trivial features of
self-avoiding walks that critically depend on the parametrization: the
asphericity of a portion of chain and the correction-to-scaling exponent.Comment: 18 pages, 4 figures. Some sections rewritten (including title and
abstract), numerical results added, references added. Accepted for
publication in J. Stat. Phy
A note on the relationship between grid structure and metrical structure in BanawaÌ
The stress system of Banawa Ì, an endangered Arawan language spoken in the Brazilian Amazon, constitutes a puzzling case study for metrical phonology. It has been claimed that its metrical representations violate the Syllable Integrity Principle (1) (Buller, Buller, and Everett (BBE) 1993, Everett 1996, 1997), one of the core universal principles in standard metrical theory, which bans representations where a foot dis- sects a heavy syllable (e.g., *(CV.CV Ì )(V.CV Ì ), *(CV Ì .CV)(V Ì .CV), where periods indicate syllable boundaries and parentheses, foot edges)
Simplified molecular detection of Leishmania parasites in various clinical samples from patients with leishmaniasis
<p>Abstract</p> <p>Background</p> <p>Molecular methods to detect <it>Leishmania </it>parasites are considered specific and sensitive, but often not applied in endemic areas of developing countries due to technical complexity. In the present study isothermal, nucleic acid sequence based amplification (NASBA) was coupled to oligochromatography (OC) to develop a simplified detection method for the diagnosis of leishmaniasis. NASBA-OC, detecting <it>Leishmania </it>RNA, was evaluated using clinical samples from visceral leishmaniasis patients from East Africa (n = 30) and cutaneous leishmaniasis from South America (n = 70) and appropriate control samples.</p> <p>Results</p> <p>Analytical sensitivity was 10 parasites/ml of spiked blood, and 1 parasite/ml of culture. Diagnostic sensitivity of NASBA-OC was 93.3% (95% CI: 76.5%-98.8%) and specificity was 100% (95% CI: 91.1%-100%) on blood samples, while sensitivity and specificity on skin biopsy samples was 98.6% (95% CI: 91.2%-99.9%) and 100% (95% CI: 46.3%-100%), respectively.</p> <p>Conclusion</p> <p>The NASBA-OC format brings implementation of molecular diagnosis of leishmaniasis in resource poor countries one step closer.</p
Osteosarcoma of the mobile spineâ
Background The aims of this analysis were to investigate features and outcome of high-grade osteosarcomas of the mobile spine. Patients and methods Since 1977, 20 Cooperative Osteosarcoma Study Group patients had a diagnosis of high-grade osteosarcomas of the mobile spine and were included in this retrospective analysis of patient-, tumor- and treatment-related variables and outcome. Results The median age was 29 years (range 5-58). Most frequent tumor sites were thoracic and lumbar spine. All but three patients had nonmetastatic disease at diagnosis. Treatment included surgery and chemotherapy for all patients, 13 were also irradiated. Eight patients failed to achieve a macroscopically complete surgical remission (five local, one primary metastases, two both), six died, two are alive, both with radiotherapy. Of 12 patients with complete remission at all sites, three had a recurrence (two local, one metastases) and died. The median follow-up of the 11 survivors was 8.7 years (range 3.1-22.3), 5-year overall and event-free survival rates were 60% and 43%. Age <40 years, nonmetastatic disease at diagnosis and complete remission predicted for better overall survival (OS, P < 0.05). Conclusions Osteosarcomas of the mobile spine are rare. With complete resection (and potentially radiotherapy) and chemotherapy, prognosis may be comparable with that of appendicular osteosarcoma
Two-Dimensional Critical Percolation: The Full Scaling Limit
We use SLE(6) paths to construct a process of continuum nonsimple loops in
the plane and prove that this process coincides with the full continuum scaling
limit of 2D critical site percolation on the triangular lattice -- that is, the
scaling limit of the set of all interfaces between different clusters. Some
properties of the loop process, including conformal invariance, are also
proved.Comment: 45 pages, 12 figures. This is a revised version of math.PR/0504036
without the appendice
Astrocytic Ion Dynamics: Implications for Potassium Buffering and Liquid Flow
We review modeling of astrocyte ion dynamics with a specific focus on the
implications of so-called spatial potassium buffering, where excess potassium
in the extracellular space (ECS) is transported away to prevent pathological
neural spiking. The recently introduced Kirchoff-Nernst-Planck (KNP) scheme for
modeling ion dynamics in astrocytes (and brain tissue in general) is outlined
and used to study such spatial buffering. We next describe how the ion dynamics
of astrocytes may regulate microscopic liquid flow by osmotic effects and how
such microscopic flow can be linked to whole-brain macroscopic flow. We thus
include the key elements in a putative multiscale theory with astrocytes
linking neural activity on a microscopic scale to macroscopic fluid flow.Comment: 27 pages, 7 figure
The signed loop approach to the Ising model: foundations and critical point
The signed loop method is a beautiful way to rigorously study the
two-dimensional Ising model with no external field. In this paper, we explore
the foundations of the method, including details that have so far been
neglected or overlooked in the literature. We demonstrate how the method can be
applied to the Ising model on the square lattice to derive explicit formal
expressions for the free energy density and two-point functions in terms of
sums over loops, valid all the way up to the self-dual point. As a corollary,
it follows that the self-dual point is critical both for the behaviour of the
free energy density, and for the decay of the two-point functions.Comment: 38 pages, 7 figures, with an improved Introduction. The final
publication is available at link.springer.co
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