Statistical mechanics of general discrete nonlinear Schr{\"o}dinger models: Localization transition and its relevance for Klein-Gordon lattices

We extend earlier work [Phys.Rev.Lett. 84, 3740 (2000)] on the statistical mechanics of the cubic one-dimensional discrete nonlinear Schrodinger (DNLS) equation to a more general class of models, including higher dimensionalities and nonlinearities of arbitrary degree. These extensions are physically motivated by the desire to describe situations with an excitation threshold for creation of localized excitations, as well as by recent work suggesting non-cubic DNLS models to describe Bose-Einstein condensates in deep optical lattices, taking into account the effective condensate dimensionality. Considering ensembles of initial conditions with given values of the two conserved quantities, norm and Hamiltonian, we calculate analytically the boundary of the 'normal' Gibbsian regime corresponding to infinite temperature, and perform numerical simulations to illuminate the nature of the localization dynamics outside this regime for various cases. Furthermore, we show quantitatively how this DNLS localization transition manifests itself for small-amplitude oscillations in generic Klein-Gordon lattices of weakly coupled anharmonic oscillators (in which energy is the only conserved quantity), and determine conditions for existence of persistent energy localization over large time scales.Comment: to be published in Physical Review

Developing university innovation capacity: how can innovation policy effectively harness universities? Capability to promote high-growth technology businesses?

Some universities and departments have been very successful in stimulating university spin- off firms (USOs). This has persuaded policy makers and university administrators to devote considerable resources to improve universities' capabilities to promote USOs, but with little tangible results. Related research has considered why some universities contributes more to business innovation than others, but whether the majority of universities can become innovation hotbeds remains an open question. This paper takes a novel interdisciplinary approach integrating insights from two separate literatures, academic entrepreneurship and university management. We start by taking the firm’s perspective and seek to understand the challenges faced by USOs and how universities can assist these firms in developing their entrepreneurial competencies. The structure and main purpose of universities are very different from that of new technology businesses and the transition from being an academic research activity to become a commercial business activity poses challenges both for the university and the USO. Much research on universities’ entrepreneurial capability focuses on ‘what’ universities can do to support USOs at the expense of ‘why’ universities’ might choose to promote USOs when they are under many intense competing demands from outside. We explore not only what universities can do to support USOs, but also how universities experience USOs’ support demands, and the circumstances under which universities can develop capability to promote USOs. We address the barriers that arise between universities and USOs and discuss mitigating factors which support the competencies of USOs whilst at the same time meet the different university stakeholders’ needs

How academic entrepreneurship meets the university: university spin-offs in stakeholder networks

Some universities and departments have been very successful in stimulating university spin-off firms (USOs). It remains an open question whether this is due to unique abilities and circumstances or if it can be stimulated at many universities. This paper seeks to discuss this question by integrating insights from two separate literatures: academic entrepreneurship and university management. We start by taking the firm’s perspective to understand the challenges faced by USOs and how universities can assist these firms in developing their entrepreneurial competencies. After that we explore why universities might choose to use their scarce resources to support USOs when the main benefits for success are accrued by the spin-off rather than the university. Here we use a stakeholder perspective to suggest how academic entrepreneurship may be seen as universities’ developing service bundles to support an entrepreneurial ecosystem that goes beyond technical and financial support. We suggest a future research and policy agenda arguing for more emphasis on understanding the USO as a university stakeholder, with relationships to a wider stakeholder set, that in turn constitute an entrepreneurial ecosystem

Models for energy and charge transport and storage in biomolecules

Two models for energy and charge transport and storage in biomolecules are considered. A model based on the discrete nonlinear Schrodinger equation with long-range dispersive interactions (LRI's) between base pairs of DNA is offered for the description of nonlinear dynamics of the DNA molecule. We show that LRI's are responsible for the existence of an interval of bistability where two stable stationary states, a narrow, pinned state and a broad, mobile state, coexist at each value of the total energy. The possibility of controlled switching between pinned and mobile states is demonstrated. The mechanism could be important for controlling energy storage and transport in DNA molecules. Another model is offered for the description of nonlinear excitations in proteins and other anharmonic biomolecules. We show that in the highly anharmonic systems a bound state of Davydov and Boussinesq solitons can exist.Comment: 12 pages (latex), 12 figures (ps

True infection or contamination in patients with positive Cutibacterium blood cultures-a retrospective cohort study

Cutibacterium is a genus often considered a contaminant when present in blood cultures, but it can also cause severe infections, especially related to implanted foreign materials. We investigated the incidence and features of patients with true Cutibacterium infection. Patients with positive Cutibacterium blood cultures between the years 2015-2020 in southern Sweden were identified through microbiology records and medical records were studied retrospectively. Cutibacterium isolates were species determined using MALDI-TOF MS. Patients were classified as having true infection or contamination according to a definition considering both clinical and microbiological features and these groups were compared. A total of 313 episodes of positive Cutibacterium blood cultures were identified in 312 patients. Of these, 49 (16%, corresponding to an incidence of 6 cases per million inhabitants per year) were classified as true infections. The most common species was Cutibacterium acnes (87%), and the majority were elderly men with comorbidities. Patients with true Cutibacterium infection often had an unknown focus of infection (n = 21) or a focus in the respiratory tract (n = 18). We identified one episode of ventriculo-peritoneal shunt infection, three episodes of aortic stent-graft infection, and one episode of infective endocarditis. Two patients, where Cutibacterium was isolated at the site of infection, had only one positive blood culture. The finding of positive Cutibacterium blood cultures should not always be considered contamination. Definitions of true Cutibacterium bacteremia with a demand that more than one blood culture must be positive may miss true infections

Clinical Significance of a 16S-rDNA Analysis of Heart Valves in Patients with Infective Endocarditis : a Retrospective Study

A substantial proportion of patients with infective endocarditis (IE) are subjected to heart valve surgery. Microbiological findings on valves are important both for diagnostics and for tailored antibiotic therapy, post-operatively. The aims of this study were to describe microbiological findings on surgically removed valves and to examine the diagnostic benefits of 16S-rDNA PCR and sequencing (16S-analysis). Adult patients who were subjected to heart valve surgery for IE between 2012 and 2021 at Skåne University Hospital, Lund, where a 16S-analysis had been performed on the valve, constituted the study population. Data were gathered from medical records, and the results from blood cultures, valve cultures, and 16S-analyses of valves were compared. A diagnostic benefit was defined as providing an agent in blood culture negative endocarditis, providing a new agent in episodes with positive blood cultures, or confirming one of the findings in episodes with a discrepancy between blood and valve cultures. 279 episodes in 272 patients were included in the final analysis. Blood cultures were positive in 259 episodes (94%), valve cultures in 60 episodes (22%), and 16S-analyses in 227 episodes (81%). Concordance between the blood cultures and the 16S-analysis was found in 214 episodes (77%). The 16S-analyses provided a diagnostic benefit in 25 (9.0%) of the episodes. In blood culture negative endocarditis, the 16S-analyses had a diagnostic benefit in 15 (75%) of the episodes. A 16S-analysis should be routinely performed on surgically removed valves in blood culture negative endocarditis. In patients with positive blood cultures, 16S-analysis may also be considered, as a diagnostic benefit was provided in some patients.IMPORTANCE This work demonstrates that it can be of importance to perform both cultures and analysis using 16S-rDNA PCR and sequencing of valves excised from patients undergoing surgery for infective endocarditis. 16S-analysis may help both to establish a microbiological etiology in cases of blood culture negative endocarditis and to provide help in situations where there are discrepancies between valve and blood cultures. In addition, our results show a high degree of concordance between blood cultures and 16S-analyses, indicating that the latter has a high sensitivity and specificity for the etiological diagnosis of endocarditis in patients who were subjected to heart valve surgery

Profitability of a Hydro Power Producer Bidding in Multiple Power Markets

AbstractThe production scheduling of a hydro power producer exposed to the day-ahead, balancing and capacity market is examined to find what profit the producer may achieve by strategically bid in the above mentioned markets. Optimizing the bidding in multiple markets is expected to be increasingly important in the coming years as the share of renewable energy in the power system grows. A multi-stage, multi-scenario, short-term deterministic prototype model undertakes this task. The producer is assumed to be a price taker and is risk neutral. The results of the optimization have shown that a hydro power producer in the case-study area increases the expected income by participating in the balancing market. The results suggest that by utilizing the balancing market, the profit may increase by up to 5.86% per day, depending on the season. This is compared with the original income when bidding into the day-ahead market only. Furthermore, the simulations of future power prices have shown that profitability is expected to increase with price volatility. These findings underline the need to include balancing markets in production planning. The capacity market, RKOM, was also implemented. This market proved not to be profitable in this case study, but the conclusion might change if the future RKOM market price rise. Measures to reduce risk are also examined, creating valuable decision support to the producer