BACKGROUND:SARS-CoV-2 can be effectively transmitted between individuals located in close proximity to each other for extended durations. Aircraft provide such conditions. Although high attack rates during flights were reported, little was known about the risk levels of aerosol transmission of SARS-CoV-2 in aircraft cabins. OBJECTIVES:The major objective was to estimate the risk of contracting COVID-19 from transmission of aerosol particles in aircraft cabins. METHODS:In two single-aisle and one twin-aisle aircraft, dispersion of generated aerosol particles over a seven-row economy class cabin section was measured under cruise and taxi conditions and simulated with a computational fluid dynamic model under cruise conditions. Using the aerosol particle dispersion data, a quantitative microbial risk assessment was conducted for scenarios with an asymptomatic infectious person expelling aerosol particles by breathing and speaking. Effects of flight conditions were evaluated using generalized additive mixed models. RESULTS:Aerosol particle concentration decreased with increasing distance from the infectious person, and this decrease varied with direction. On a typical flight with an average shedder, estimated mean risk of contracting COVID-19 ranged from 1.3×10-3 to 9.0×10-2. Risk increased to 7.7×10-2 with a super shedder (<3% of cases) on a long flight. Risks increased with increasing flight duration: 2-23 cruise flights of typical duration and 2-10 flights of longer duration resulted in at least 1 case of COVID-19 due to onboard aerosol transmission by one average shedder, and in the case of one super shedder, at least 1 case in 1-3 flights of typical duration cruise and 1 flight of longer duration. DISCUSSION:Our findings indicate that the risk of contracting COVID-19 by aerosol transmission in an aircraft cabin is low, but it will not be zero. Testing before boarding may help reduce the chance of a (super)shedder boarding an aircraft and mask use further reduces aerosol transmission in the aircraft cabin. https://doi.org/10.1289/EHP11495.

Library catalogues may be connected to the linked data cloud through various types of thesauri. For name authority thesauri in particular I would like to suggest a fundamental break with the current distributed linked data paradigm: to make a transition from a multitude of different identifiers to using a single, universal identifier for all relevant named entities, in the form of the Wikidata identifier. Wikidata (https://wikidata.org) seems to be evolving into a major authority hub that is lowering barriers to access the web of data for everyone. Using the Wikidata identifier of notable entities as a common identifier for connecting resources has significant benefits compared to traversing the ever-growing linked data cloud. When the use of Wikidata reaches a critical mass, for some institutions, Wikidata could even serve as an authority control mechanism.

High-performance military aircraft regularly operate inside hardened aircraft shelters (HAS). The F-35A aircraft must be certified as safe to operate inside a HAS before it can be deployed and used in such structures worldwide. Acoustic levels at maintainer locations allow for noise dose estimates and regulation of personnel mission support in HASs to mitigate risks of hearing damage. Acoustic levels impinging on the airframe are compared against engineering design limits in order to prevent a reduction in operational lifespan of the aircraft due to acoustic fatigue. The Air Force Research Laboratory, the Royal Netherlands Air Force, and the Dutch national laboratories NLR and TNO collaborated on a set of acoustic measurements for an F-35A operating inside a HAS at Leeuwarden airbase in the Netherlands. The methods, analysis, and qualitative findings of the acoustic measurements are presented here. [Work supported by RNLAF and by the F-35 JPO. Distribution A: Approved for public release; distribution unlimited. Cleared 01/24/2017; JSF17-035.]

We improved access to the collection of Dutch historical newspapers of the Koninklijke Bibliotheek by linking named entities in the newspaper articles to corresponding Wikidata descriptions by means of machine learning techniques and crowdsourcing. Indexing the Wikidata identifiers for named entities together with the newspaper articles opens up new possibilities for retrieving articles that mention these resources and searching the newspaper collection using semantic relations from Wikidata. In this paper we describe our steps so far in setting up this combination of entity linking, machine learning and crowdsourcing in our research environment as well as our planned activities aimed at improving the quality of the links and extending the semantic search capabilities.

Semantic enrichment provides new possibilities for discovery and presentation of our data. At the National Library of the Netherlands research department we have created a generic infrastructure for enriching objects from our collections with, for example, links to related information. This article summarizes the main ideas behind this infrastructure and presents its implementation, with particular reference to the enrichment process of extracting named entities from textual content and linking them to resource descriptions in the Linked Data cloud. Other content providers may take a similar approach when enriching their data. We argue that such initiatives will be more beneficial for our users when infrastructures are connected and accessible with the same APIs. Alignment of data formats and identifiers, moreover, can help connect our content to others' content, e.g. through the use of a single identifier for each relevant resource across collections and institutions.

The usability, disclosure and value of digitized full text collections can be improved by linking named entities or events in text to linked data [1]. These data can be used to obtain additional information and it can be used in queries for expressing conditions in terms of semantic relations. When the links are obtained automatically, we need disambiguation by users or by sophisticated algorithms. Providers of full text data will have to deal with all of these aspects. In this paper we discuss our plans and work in progress and propose a common approach to increase interoperability between text data from different providers. We feel that it should be the ambition of every provider of text collections to have as many named entities as possible in text identified with globally unique persistent identifiers, linked to one or more resource descriptions to guide users through the enormous amount of digitized text. Notice: This work reflects the personal view of the authors and does not yet reflect current policies of the KB.

The usability, disclosure and value of digitized full text collections can be improved by linking named entities or events in text to linked data [1]. These data can be used to obtain additional information and it can be used in queries for expressing conditions in terms of semantic relations. When the links are obtained automatically, we need disambiguation by users or by sophisticated algorithms. Providers of full text data will have to deal with all of these aspects. In this paper we discuss our plans and work in progress and propose a common approach to increase interoperability between text data from different providers. We feel that it should be the ambition of every provider of text collections to have as many named entities as possible in text identified with globally unique persistent identifiers, linked to one or more resource descriptions to guide users through the enormous amount of digitized text. Notice: This work reflects the personal view of the authors and does not yet reflect current policies of the KB.

Within the Europeana Newspapers project (www.europeana-newspapers.eu), full-text will be produced for over 10 million pages of digitised historical newspapers by applying Optical Character Recognition (OCR) and Optical Layout Recognition (OLR). In order to further increase the usability of the full-text, Named Entity Recognition (NER) is also applied to materials in Dutch, German and French language. The main aim of NER is to identify and classify entities such as persons, locations and organisations in the full-text in order to enhance the searchability, and to subsequently link them to online resource descriptions and authority files (e.g. DBPedia, VIAF). By also cross-linking the named entities, a whole scale of possibilities in terms of analyzing large multilingual corpora can be unlocked. Therefore, the KB National Library of the Netherlands has been adapting an open source tool from Stanford University for training a state-of-theart NER system specifically for Europeana Newspapers. Some of the main considerations in producing the software were scalability and the support for the standards and formats that are most widely used in newspaper digitisation such as METS and ALTO. Another important requirement was to retain information about the exact location of the named entities on a page throughout the refinement process, so they can for example be highlighted in a viewer. We will introduce the overall workflow for NER as implemented in Europeana Newspapers, discuss some design considerations as well as technical issues and lessons learned while building the software, and present first results from applying the system to historical newspaper content from three different languages.

Web search results form the basis for a variety of further actions by users, including requesting related information in Wikipedia, language translation, transforming an abstract into a word cloud, etc., actions which the provider of the original data is typically unaware of. SIWA (Schema for the Integration of Web Applications) was developed to describe how a user wants data fields from a web application to be used as input for other web applications. We propose a mechanism to add the appropriate links to presented data. The intent is to develop a standard for these service integration descriptions that can be shared by users and content providers. Originally developed as part of the EuropeanaConnect project but not highly publicized, SIWA has been simplified and improved in an effort to lower the implementation barrier. This article discusses the recent changes in approach with respect to SIWA, and current trends in the use of the Internet, that should increase the chance of a broad adoption of this concept of service integration, and hopefully trigger new initiatives supporting user defined service integration by means of SIWA.

The quality and value of noise measurements of high-performance jets depend on a complex set of factors. A thorough preparation and analysis phase is not always standard practice. Critical factors during preparation are, for example, the selection of the location, the aircraft, the communication with the pilot, the design of the flight profiles during the runs, the method and instrumentation for recording of the aircraft performance, and noise and meteorological conditions during the test. After the test, a thorough analysis of the data has to be performed to select the data with the required quality. Further processing of this raw recorded data will lead to noise levels in corrected LAmax, SEL, or other metrics. In this paper attention is paid to the critical factors that can be influenced prior to the test and after the test to maximize the quality of the data used for noise calculations. A good preparation of the test and an analysis of the quality of the measured data set are essential to guarantee the acquisition of a high quality data set after fly-over noise measurements. The paper contains critical factors of a noise test with aircraft types like the F 16, F 18, and F 35.

Retinitis pigmentosa (RP) is a heterogeneous group of inherited neurodegenerative diseases affecting photoreceptors and causing blindness. Many human cases are caused by mutations in the rhodopsin gene. An important question regarding RP pathology is whether different genetic defects trigger the same or different cell death mechanisms. To answer this question, we analysed photoreceptor degeneration in P23H and S334ter transgenic rats carrying rhodopsin mutations that affect protein folding and sorting respectively. We found strong activation of calpain and poly(ADP-ribose) polymerase (PARP) in both mutants, concomitant with calpastatin down-regulation, increased oxidative DNA damage and accumulation of PAR polymers. These parameters were strictly correlated with the temporal progression of photoreceptor degeneration, mirroring earlier findings in the phosphodiesterase-6 mutant rd1 mouse, and suggesting execution of non-apoptotic cell death mechanisms. Interestingly, activation of caspases-3 and -9 and cytochrome c leakage—key events in apoptotic cell death—were observed only in the S334ter mutant, which also showed increased expression of PARP-1. The identification of the same metabolic markers triggered by different mutations in two different species suggests the existence of common cell death mechanisms, which is a major consideration for any mutation independent treatment.

Seasonal effects of photoperiod (16 h light (L): 8 h dark (D) and 8 h L: 16 h D) and temperature (18 and 8–9 °C) were studied on the ovary of the three-spined stickleback at 2-month intervals throughout the year. At the higher temperature, advanced oocyte development took place only in 16 h L: 8 h D in November and January, while in March and May an increasing proportion of the females matured also in 8 h L: 16 h D. Many fish in 8 h L: 16 h D, 18 °C, in November–May showed a marked regression of the ovaries and large numbers of atretic eggs. At the lower temperature in November–May the ovaries developed slowly, or showed little change compared with the initial controls. No consistent effect of photoperiod was found at the lower temperature in any season. The ovaries regressed in July, fastest at the higher temperature. No photoperiodic effects could, however, be detected. At the commencement of the September experiment the ovaries were in a regressed state and no advanced oocyte development was reached in any group.

The role of oxidative stress within photoreceptors (PRs) in inherited photoreceptor degeneration (IPD) is unclear. We investigated this question using four IPD mouse models (Pde6b(rd1/rd1), Pde6b(atrd1/atrd1), Rho(-/-) and Prph2(rds/rds)) and compared the abundance of reduced glutathione (GSH) and the activity of mitochondrial NADH:ubiquinone oxidoreductase (complex I), which is oxidative stress sensitive, as indirect measures of redox status, in the retinas of wild type and IPD mice. All four IPD mutants had significantly reduced retinal complex I activities (14-29% of wild type) and two showed reduced GSH, at a stage prior to the occurrence of significant cell death, whereas mitochondrial citrate synthase, which is oxidative stress insensitive, was unchanged. We orally administered the mitochondrially targeted anti oxidant MitoQ in order to reduce oxidative stress but without any improvement in retinal complex I activity, GSH or rates of PR degeneration. One possible source of oxidative stress in IPDs is oxygen toxicity in the outer retina due to reduced consumption by PR mitochondria. We therefore asked whether a reduction in the ambient O(2) concentration might improve PR survival in Pde6b(rd1/rd1) retinal explants either directly, by reducing reactive oxygen species formation, or indirectly by a neuroprotective mechanism. Pde6b(rd1/rd1) retinal explants cultured in 6% O(2) showed 31% less PR death than normoxic explants. We conclude that (i) mitochondrial oxidative stress is a significant early feature of IPDs; (ii) the ineffectiveness of MitoQ may indicate its inability to reduce some mediators of oxidative stress, such as hydrogen peroxide; and (iii) elucidation of the mechanisms by which hypoxia protects mutant PRs may identify novel neuroprotective pathways in the retina.

The rd1 natural mutant is one of the first and probably the most commonly studied mouse model for retinitis pigmentosa (RP), a severe and frequently blinding human retinal degeneration. In several decades of research, the link between the increase in photoreceptor cGMP levels and the extremely rapid cell death gave rise to a number of hypotheses. Here, we provide clear evidence that the presence of cyclic nucleotide gated (CNG) channels in the outer segment membrane is the key to rod photoreceptor loss. In Cngb1(-/-) × rd1 double mutants devoid of regular CNG channels, cGMP levels are still pathologically high, but rod photoreceptor viability and outer segment morphology are greatly improved. Importantly, cone photoreceptors, the basis for high-resolution daylight and colour vision, survived and remained functional for extended periods of time. These findings strongly support the hypothesis of deleterious calcium (Ca(2+))-influx as the cause of rapid rod cell death and highlight the importance of CNG channels in this process. Furthermore, our findings suggest that targeting rod CNG channels, rather than general Ca(2+)-channel blockade, is a most promising symptomatic approach to treat otherwise incurable forms of cGMP-related RP.

J. Neurochem. (2010) 115, 930–940.AbstractPhotoreceptor degeneration is the hallmark of a group of inherited blinding diseases collectively termed retinitis pigmentosa (RP); a major cause of blindness in humans. RP is at present untreatable and the underlying neurodegenerative mechanisms are largely unknown, even though the genetic causes are often established. The activation of calpain‐type proteases may play an important role in cell death in various neuronal tissues, including the retina. We therefore tested the efficacy of two different calpain inhibitors in preventing cell death in the retinal degeneration (rd1) human homologous mouse model for RP. Pharmacological inhibition of calpain activity in rd1 organotypic retinal explants had ambiguous effects on photoreceptor viability. Calpain inhibitor XI had protective effects when applied for short periods of time (16 h) but demonstrated substantial levels of toxicity in both wild‐type and rd1 retina when used over several days. In contrast, the highly specific calpain inhibitor calpastatin peptide reduced photoreceptor cell death in vitro after both short and prolonged exposure, an effect that was also evident after in vivo application via intravitreal injection. These findings highlight the importance of calpain activation for photoreceptor cell death but also for photoreceptor survival and propose the use of highly specific calpain inhibitors to prevent or delay RP.