Accelerated expansion of an open universe, and string theory realizations

Recently, many works have tried to realize cosmological accelerated expansion in string theory models in the asymptotic regions of field space, with a typical scalar potential $V(\varphi)$ having an exponential fall-off $e^{-\gamma\, \varphi}$. Those attempts have been plagued by the fact that $V$ is too steep, namely $\gamma \geq 2/\sqrt{d-2}$ in a $d$-dimensional spacetime. We revisit the corresponding dynamical system for arbitrary $d$ and $\gamma$, and show that for an open universe ($k=-1$), there exists a new stable fixed point $P_1$ precisely if $\gamma > 2/\sqrt{d-2}$. Building on the recent work arXiv:2210.10813, we show in addition that cosmological solutions asymptoting to $P_1$ exhibit accelerated expansion in various fashions (semi-eternal, eternal, transient with parametrically controlled number of e-folds, or rollercoaster). We finally present realizations in string theory of these cosmological models with asymptotically accelerating solutions, for $d=4$ or $d=10$.Comment: 37 pages, 7 figures and 2 table

Who Succeeds In The Murky Middle?

This exploratory study examines technically educated middle managers performing ad hoc projects in flat organizations and develops a typology for examining the behavioral patterns associated with their effectiveness. Initial findings indicate the greatest success was achieved by “Type 1” managers (the Leaders) who were able to integrate collaborative selling skills and technical expertise within a web of both formal and informal interactions. Moderate success accrued to “Type 2” managers (the Learners) who used collaborative selling skills to develop social networks that allowed them to expand their own technical expertise. “Type 3” managers (the Leapers) primarily relied upon technical expertise as the tool for interacting with others and enjoyed only modest success. Although “Type 4” managers (the Laggards) had the requisite technical knowledge base, they were the least successful because their lack of collaborative selling skills made it difficult to utilize a compensatory social network. Suggestions are provided for leaders seeking to leverage and direct the abilities of key staff

An Approach to Integrate Distributed Systems of Medical Devices in High Acuity Environments

This paper presents a comprehensive solution to build a distributed system of medical devices in high acuity environments. It is based on the concept of a Service Oriented Medical Device Architecture. It uses the Devices Profile for Web Services as a transport layer protocol and enhances it to the Medical Devices Profile for Web Service (MDPWS) to meet medical requirements. By applying the ISO/IEEE 11073 Domain Information Model, device data can be semantically described and exchanged by means of a generic service interface. Data model and service interface are subsumed under the Basic Integrated Clinical Environment Specification (BICEPS). MDPWS and BICEPS are implemented as part of the publically available openSDC stack. Performance measurements and a real world setup prove that openSDC is feasible to be deployed in distributed systems of medical devices

Automated consistent truncations and stability of flux compactifications

Classical flux compactifications contribute to a well-controlled corner of the string landscape, therefore providing an important testing ground for a variety of conjectures. We focus here on type II supergravity compactifications on 6d group manifolds towards 4d maximally symmetric spacetimes. We develop a code where the truncation to left-invariant scalars and the dimensional reduction to a 4d theory are automated, for any possible configuration of Op-planes and Dp-branes. We then prove that any such truncation is consistent. We further compute the mass spectrum and analyse the stability of many de Sitter, Minkowski or anti-de Sitter solutions, as well as their consistency with swampland conjectures.Comment: 31 pages. The numerical code MSSV and a corresponding database are provided as ancillary file

Understanding the Platform Economy: Signals, Trust, and Social Interaction

Two-sided markets are gaining increasing importance. Examples include accommodation and car sharing, resale, shared mobility, crowd work, and many more. As these businesses rely on transactions among users, central aspects to virtually all platforms are the creation and maintenance of trust. While research has considered effects of trust-building on diverse platforms in isolation, the overall platform landscape has received much less attention. However, cross-platform comparison is important since platforms vary in their degree of social interaction, which, as we demonstrate in this paper, determines the adequacy and use of different trust mechanisms. Based on actual market data, we examine the mechanisms platforms employ and how frequent users rely on them. We contrast this view against survey data on users’ perceptions of the context-specific importance of these trust-building tools. Our findings provide robust evidence for our reasoning on the relation between platforms’ degree of social interaction and the associated expressive trust cues

The effect of aqueous fluid on viscous relaxation of garnet and modification of inclusion pressures after entrapment

The elastic interaction between an inclusion and its host is often employed to study metamorphic processes based on the assumption that the host is not affected by processes such as creep that irreversibly releases stress. However, it is not well understood how fast inelastic relaxation of stress may occur and under what conditions the elastic regime holds for each inclusion-host system. To provide new constraints for the widely used systems of quartz and zircon inclusions in garnet, we performed heating experiments on almandine-pyrope and spessartine garnets under graphite, N2+H2, or H2O+Ar fluxed conditions at different temperatures. Raman spectroscopy was used to measure the same quartz and zircon inclusions after different heating times. The Raman-band wavenumbers undergo time-dependent decreases in quartz inclusions and increase in zircon inclusions under H2O+Ar conditions and exhibit a greater final shift than under graphite and N2+H2 buffered conditions. Under graphite-buffered conditions, the wavenumbers of Raman bands measured on zircon and quartz stabilise after the first heating step, after which no change was observed. Electron backscatter diffraction results reveal greater misorientation around the heated inclusions compared to unheated inclusions, implying a greater dislocation density after heating. Raman mapping reveals that stress heterogeneity in the garnet host develops at an early stage of heating and fades away afterward, indicating dispersal of dislocations into the host. Fitting a visco-elastic model to the Raman data of garnet fluxed with N2+H2 or Ar+H2O allows an estimate of flow-law parameters for garnet around quartz inclusions, similar to those obtained by conventional deformation experiments. The results demonstrate the weakening effect of aqueous fluid on garnet. The data also indicate that the garnet can hold inclusion pressure at elevated temperatures under a dry and reducing environment. This study provides information on the relaxation rate of pressurized inclusions in garnet at different temperatures and within different external environments. Furthermore, the use of inclusion-host pairs for studying creep processes offers a complementary approach to conventional deformation experiments to better understand the rheological behaviour of earth materials

A population-based study of patients in Danish hospitals who are in their last year of life

Introduction: Little is known about the prevalence and distribution in Denmark of hospital inpatients who are in their last year of life. Knowledge about these patients could attract attention towards needs for their identification and for optimisation of end-of-life care initiatives. The aims of this study were to determine the proportion of prevalent in-patients who died during the following 12 months, to present characteristics among deceased and survivors, and to identify in which hospitals, departments or specialities imminently dying patients appear most frequently. Methods: This was a record-linkage cohort study of all patients, who were in public somatic hospitals in Denmark on 10 April 2013. Patients were followed for one year. Results: A total of 13,412 inpatients were resident in 26 Danish hospitals on 10 April 2013 (range: 1,173-106 patients per hospital). 22% died during the one-year follow-up (range: 17-37% per hospital. 24% men, 20% women); 27% in medical, 15% in surgical and 50% in oncological/haematological departments. The median time to death was 59 days (54/66 days for women/men). 61% died in hospital. Deceased patients were older than survivors (76 versus 64 years, median) and had longer hospital index-stays (13 versus six days, median). 25% of the deceased (n = 740) died during the index episode, corresponding to 5.5% of all the prevalent inpatients. Conclusions: More than one in five inpatients in Danish hospitals are imminently dying or in their last year of life. Knowledge of the patients’ uneven distribution in the hospital system can underpin organisational strategies to focus on end-of-life care provision