77 research outputs found
Bitpipe vs. service: Why do pure service providers outperform fully integrated operators?
With the emergence of pure internet-based service providers, the business landscape of fully integrated telecommunications providers - industry incumbents that provide services on their own infrastructure - has changed massively. While various pure service providers exhibit successful business models and high performance, the services offered by the integrated telecommunication firms are not able to compete on neither price nor user experience. To shed light on this issue, we build upon work that has applied a complex systems perspective on performance - how firms manage to configure a large set of interdependent activities affects the performance of the overall activity system. We develop a simulation model to illustrate the effects of a) configuring only interdependent service-related activities, while building on an existing (external) infrastructure, and b) configuring both infrastructure-related and service-related activities at the same time. Our results point to a mechanism that helps explain the underperformance of the fully integrated operators. Pure service providers can improve the performance of their services speedily, as they can focus on optimizing only the service-related activities and adapting them to an existing infrastructure. Fully integrated operators, in contrast, will likely be concerned with both infrastructure and service components, taking into account also the interdependencies between these two domains. While this approach can help reap synergy effects and yield a performance advantage in the long run, it requires more time and results in a lower performance in the short run. Put differently, the objective of the integrated operators to integrate their bitpipe and service business puts these firms at a disadvantage when compared to their specialized competitors. We illustrate this mechanism with two case studies that show how fully integrated operators adapted their infrastructure in response to their service activities, which in return triggered further adaptations and coordination effort. --Telecommunication industry,complex systems,organizational search
Subjective and objective measures of activity in depressed and non-depressed individuals in everyday life
PV installations based on vertically mounted bifacial modules evaluation of energy yield and shading effects
Bifacial solar modules promise an increased energy yield, compared to systems with standard, monofacial panels, and also offer new opportunities with regard to the installation. One particular approach is the vertical mounting of PV modules, which is reported to be an effective measure to avoid soiling or dust deposition and is an option to obtain a broadened energy generation profile. In spite of the general interest in this type of installation, the amount of published data is very limited, especially with regard to arrays, for which pronounced shading effects can be expected.
In this work we present an analysis of the energy yield and the respective losses for arrays of vertically mounted bifacial solar modules with varied installation conditions
Reproducibility in modeling and simulation of the knee:Academic, industry, and regulatory perspectives
Stakeholders in the modeling and simulation (M&S) community organized a workshop at the 2019 Annual Meeting of the Orthopaedic Research Society (ORS) entitled “Reproducibility in Modeling and Simulation of the Knee: Academic, Industry, and Regulatory Perspectives.” The goal was to discuss efforts among these stakeholders to address irreproducibility in M&S focusing on the knee joint. An academic representative from a leading orthopedic hospital in the United States described a multi-institutional, open effort funded by the National Institutes of Health to assess model reproducibility in computational knee biomechanics. A regulatory representative from the United States Food and Drug Administration indicated the necessity of standards for reproducibility to increase utility of M&S in the regulatory setting. An industry representative from a major orthopedic implant company emphasized improving reproducibility by addressing indeterminacy in personalized modeling through sensitivity analyses, thereby enhancing preclinical evaluation of joint replacement technology. Thought leaders in the M&S community stressed the importance of data sharing to minimize duplication of efforts. A survey comprised 103 attendees revealed strong support for the workshop and for increasing emphasis on computational modeling at future ORS meetings. Nearly all survey respondents (97%) considered reproducibility to be an important issue. Almost half of respondents (45%) tried and failed to reproduce the work of others. Two-thirds of respondents (67%) declared that individual laboratories are most responsible for ensuring reproducible research whereas 44% thought that journals are most responsible. Thought leaders and survey respondents emphasized that computational models must be reproducible and credible to advance knee M&S.</p
Association of Mortality and Risk of Epilepsy With Type of Acute Symptomatic Seizure After Ischemic Stroke and an Updated Prognostic Model
IMPORTANCE: Acute symptomatic seizures occurring within 7 days after ischemic stroke may be associated with an increased mortality and risk of epilepsy. It is unknown whether the type of acute symptomatic seizure influences this risk. OBJECTIVE: To compare mortality and risk of epilepsy following different types of acute symptomatic seizures. DESIGN, SETTING, AND PARTICIPANTS: This cohort study analyzed data acquired from 2002 to 2019 from 9 tertiary referral centers. The derivation cohort included adults from 7 cohorts and 2 case-control studies with neuroimaging-confirmed ischemic stroke and without a history of seizures. Replication in 3 separate cohorts included adults with acute symptomatic status epilepticus after neuroimaging-confirmed ischemic stroke. The final data analysis was performed in July 2022. EXPOSURES: Type of acute symptomatic seizure. MAIN OUTCOMES AND MEASURES: All-cause mortality and epilepsy (at least 1 unprovoked seizure presenting >7 days after stroke). RESULTS: A total of 4552 adults were included in the derivation cohort (2547 male participants [56%]; 2005 female [44%]; median age, 73 years [IQR, 62-81]). Acute symptomatic seizures occurred in 226 individuals (5%), of whom 8 (0.2%) presented with status epilepticus. In patients with acute symptomatic status epilepticus, 10-year mortality was 79% compared with 30% in those with short acute symptomatic seizures and 11% in those without seizures. The 10-year risk of epilepsy in stroke survivors with acute symptomatic status epilepticus was 81%, compared with 40% in survivors with short acute symptomatic seizures and 13% in survivors without seizures. In a replication cohort of 39 individuals with acute symptomatic status epilepticus after ischemic stroke (24 female; median age, 78 years), the 10-year risk of mortality and epilepsy was 76% and 88%, respectively. We updated a previously described prognostic model (SeLECT 2.0) with the type of acute symptomatic seizures as a covariate. SeLECT 2.0 successfully captured cases at high risk of poststroke epilepsy. CONCLUSIONS AND RELEVANCE: In this study, individuals with stroke and acute symptomatic seizures presenting as status epilepticus had a higher mortality and risk of epilepsy compared with those with short acute symptomatic seizures or no seizures. The SeLECT 2.0 prognostic model adequately reflected the risk of epilepsy in high-risk cases and may inform decisions on the continuation of antiseizure medication treatment and the methods and frequency of follow-up
Mass Mortality of Adult Male Subantarctic Fur Seals: Are Alien Mice the Culprits?
Background: Mass mortalities of marine mammals due to infectious agents are increasingly reported. However, in contrast to previous die-offs, which were indiscriminate with respect to sex and age, here we report a land-based mass mortality of Subantarctic fur seals with apparent exclusivity to adult males. An infectious agent with a male-predilection is the most plausible explanation for this die-off. Although pathogens with gender-biased transmission and pathologies are unusual, rodents are known sources of male-biased infectious agents and the invasive Mus musculus house mouse, occurs in seal rookeries. Methodology / Principal Findings: Molecular screening for male-biased pathogens in this potential rodent reservoir host revealed the absence of Cardiovirus and Leptospirosis genomes in heart and kidney samples, respectively, but identified a novel Streptococcus species with 30 % prevalence in mouse kidneys. Conclusions / Significance: Inter-species transmission through environmental contamination with this novel bacterium, whose congenerics display male-bias and have links to infirmity in seals and terrestrial mammals (including humans)
The neutron and its role in cosmology and particle physics
Experiments with cold and ultracold neutrons have reached a level of
precision such that problems far beyond the scale of the present Standard Model
of particle physics become accessible to experimental investigation. Due to the
close links between particle physics and cosmology, these studies also permit a
deep look into the very first instances of our universe. First addressed in
this article, both in theory and experiment, is the problem of baryogenesis ...
The question how baryogenesis could have happened is open to experimental
tests, and it turns out that this problem can be curbed by the very stringent
limits on an electric dipole moment of the neutron, a quantity that also has
deep implications for particle physics. Then we discuss the recent spectacular
observation of neutron quantization in the earth's gravitational field and of
resonance transitions between such gravitational energy states. These
measurements, together with new evaluations of neutron scattering data, set new
constraints on deviations from Newton's gravitational law at the picometer
scale. Such deviations are predicted in modern theories with extra-dimensions
that propose unification of the Planck scale with the scale of the Standard
Model ... Another main topic is the weak-interaction parameters in various
fields of physics and astrophysics that must all be derived from measured
neutron decay data. Up to now, about 10 different neutron decay observables
have been measured, much more than needed in the electroweak Standard Model.
This allows various precise tests for new physics beyond the Standard Model,
competing with or surpassing similar tests at high-energy. The review ends with
a discussion of neutron and nuclear data required in the synthesis of the
elements during the "first three minutes" and later on in stellar
nucleosynthesis.Comment: 91 pages, 30 figures, accepted by Reviews of Modern Physic
The Crowdsourced Replication Initiative: Investigating Immigration and Social Policy Preferences. Executive Report.
In an era of mass migration, social scientists, populist parties and social movements raise concerns over the future of immigration-destination societies. What impacts does this have on policy and social solidarity? Comparative cross-national research, relying mostly on secondary data, has findings in different directions. There is a threat of selective model reporting and lack of replicability. The heterogeneity of countries obscures attempts to clearly define data-generating models. P-hacking and HARKing lurk among standard research practices in this area.This project employs crowdsourcing to address these issues. It draws on replication, deliberation, meta-analysis and harnessing the power of many minds at once. The Crowdsourced Replication Initiative carries two main goals, (a) to better investigate the linkage between immigration and social policy preferences across countries, and (b) to develop crowdsourcing as a social science method. The Executive Report provides short reviews of the area of social policy preferences and immigration, and the methods and impetus behind crowdsourcing plus a description of the entire project. Three main areas of findings will appear in three papers, that are registered as PAPs or in process
Polymeric particulates for subunit vaccine delivery
Vaccines still represent the best long-term treatment option for reducing many infectious diseases, including acquired immune deficiency syndrome (AIDS), malaria, and tuberculosis. Therefore, to effectively combat these severe diseases, it is of utmost importance to develop and explore novel and more efficient delivery modalities and administration routes. In this context, new polymeric nano- and microparticulate delivery platforms may represent an alternative and/or complementary therapeutic option. With the help of modern polymer chemistry, an increased number of sophisticated architectures have been developed, although these materials are in terms of bio applications still in relatively early stages. Therefore, a lot of recent attention has been dedicated to designing and tailoring novel particulates delivery systems with focus to create more efficient delivery platform. Various structures, including nanogels, nanocapsules, nano- and microparticles, dendrimers, and different hierarchical assemblies in solution have been studied in vaccine delivery. However, none of these explored platforms until now fully complies with basic delivery requirements like biocompatibility, non-toxicity, high encapsulation efficiency, and the ability to induce prolonged immune responses. In general, the unique structural and mechanical properties of polymers and their abilities to create three-dimensional structures or hybrid systems is under intensive investigation and hold a great promise in vaccine delivery
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