198 research outputs found
On the determination of optimal designs for an interference model
This paper generalizes Kushner's (1997) method for finding optimal repeated measurements designs to optimal designs under an interference model. The model we assume is for a one-dimensional layout without guard plots and with different left and right neighbour effects. The resulting optimal designs may need many blocks or may not even exist as a finite design. The results give lower bounds for optimality criteria on finite designs, and the design structure can be used to suggest efficient small designs
Optimality of Type I Orthogonal Arrays for Cross-over Models with Correlated Errors
We show that binary designs for cross-over models obtained from orthogonal arrays are universally optimal under correlated errors
Deliverable 7.2. Report on methodology for balancing user acceptance, robustness and performance
The primary goal of this deliverable is to provide an overview of the methodology for acceptance testing that will be used during the tests conducted in T7.1, T7.2 and T7.3 within the PROSPECT project. The report starts with a description of the main characteristics of the most relevant accident scenarios where safety improvements are necessary. Among all use cases identified in WP3, twelve have been especially selected by the project to be implemented in the demonstrators: 9 for cyclists and 3 for pedestrians. Behaviours such as the velocity, distance and offset of the vehicle and cyclist are defined, so that the Safe Scenario, Critical Scenario and Possible Critical Scenario can be realized on the test tracks or in simulator environments. A literature review covering acceptance evaluation issues is then presented, outlining the questionnaires that are generally used to evaluate subjective measures, such as acceptance and trust. The methodology developed for Task 7.3 is then based on such questionnaires to be administered in tests and experiments that will evaluate PROSPECT systems. By using common questionnaires, this task facilitates an overall evaluation of the acceptance of all the developed functions. The methodology is presented in section 4 of this report, including a tool for data collection (LimeSurvey). This tool makes it possible for participants in evaluation studies to answer questions on various displays, to the convenience of the experimenters. In order to balance the user acceptance to the robustness and performance of the tested systems, all answers to the questionnaires will be linked to the PROSPECT functions tested and to the quality of the PROSPECT systems functioning. This methodology will be used at different times of the tests: before running a test/experiment (questionnaire 1 - participant information and questionnaire 3 - global expected acceptance of the system or a priori acceptability), during the test/experiment (questionnaire 2 - feedback on each situation) and after the test/experiment (questionnaire 3 - global acceptance of the system after having experienced it). At the end of this document, a section briefly describes all the experiments currently planned that will use the methodology within WP7. Their results will be reported in Deliverable 7.3 Report on simulator test results and driver acceptance of PROSPECT functions
Untersuchungen zur Optimierung von barrierefreien visuellen Kontrasten
Die visuelle Barrierefreiheit ist eine Voraussetzung dafür, dass Personen mit Seheinschränkungen selbstständig am öffentlichen Leben teilnehmen können. In Anforderungen und Normen gibt es deshalb Mindestkontraste und Vorgaben für die Reflexionsgrade der Materialen, mit denen die Sehobjekte realisiert werden müssen. Die Anforderungen an die Kontraste sind so groß, dass sie mit vielen Materialen nur schwer erfüllt werden können. Es ist bekannt, dass eine Optimierung der Beleuchtung dazu führt, dass auch weniger hohe Kontraste sicher erkannt werden. Dazu zählen die Erhöhung der Leuchtdichte und die Vermeidung von Blendung. Im Rahmen einer Forschung wurde ein Teststand entwickelt, mit dem die Parameter gezielt variiert werden konnten und an Testpersonen Untersuchungen zum Kontrastsehen durchgeführt wurden. Die Erhöhung der Umfeldleuchtdichte führte dabei zu einer Verbesserung der Wahrnehmung von Kontrasten. Trotz Erhöhung der Umfeldleuchtdichte konnte nicht jeder Kontrast von allen Probanden erkannt werden. Direktblendung führt dazu, dass Kontraste schlechter wahrgenommen wurden
Untersuchungen zur Optimierung von barrierefreien visuellen Kontrasten
Die visuelle Barrierefreiheit ist eine Voraussetzung dafür, dass Personen mit Seheinschränkungen selbstständig am öffentlichen Leben teilnehmen können. In Anforderungen und Normen gibt es deshalb Mindestkontraste und Vorgaben für die Reflexionsgrade der Materialen, mit denen die Sehobjekte realisiert werden müssen. Die Anforderungen an die Kontraste sind so groß, dass sie mit vielen Materialen nur schwer erfüllt werden können. Es ist bekannt, dass eine Optimierung der Beleuchtung dazu führt, dass auch weniger hohe Kontraste sicher erkannt werden. Dazu zählen die Erhöhung der Adaptations-Leuchtdichte und die Vermeidung von Blendung. Im Rahmen einer Forschung wurde ein Teststand entwickelt, mit dem die Parameter gezielt variiert werden können und an dem mit Testpersonen Untersuchungen zum Kontrastsehen durchgeführt werden. Es werden das Testkonzept und erste Ergebnisse vorgestellt
Investigation of NiOx-hole transport layers in triple cation perovskite solar cells
Perovskite solar cells with a planar p-i-n device structure offer easy processability at low temperatures, suitable for roll-to-roll fabrication on flexible substrates. Herein we investigate different hole transport layers (solution processed NiOx, sputtered NiOx, PEDOT:PSS) in planar p-i-n perovskite solar cells using the triple cation lead halide perovskite Cs0.08(MA0.17FA0.83)0.92Pb(I0.83Br0.17)3 as absorber layer. Overall, reproducible solar cell performances with power conversion efficiencies up to 12.8% were obtained using solution processed NiOx as hole transport layer in the devices. Compared to that, devices with PEDOT:PSS as hole transport layer yield efficiencies of approx. 8.4%. Further improvement of the fill factor was achieved by the use of an additional zinc oxide nanoparticle layer between the PC60BM film and the Ag electrode
Radio and spectroscopic properties of miniature radio galaxies: revealing the bulk of the radio-loud AGN population
We explore radio and spectroscopic properties of a sample of 14 miniature
radio galaxies, i.e. early-type core galaxies hosting radio-loud AGN of
extremely low radio power, 10^(27-29) erg s^(-1) Hz^(-1) at 1.4 GHz. Miniature
radio galaxies smoothly extend the relationships found for the more powerful
FRI radio galaxies between emission line, optical and radio nuclear
luminosities to lower levels. However, they have a deficit of a factor of ~100
in extended radio emission with respect to that of the classical example of
3CR/FRI. This is not due to their low luminosity, since we found radio galaxies
of higher radio core power, similar to those of 3CR/FRI, showing the same
behavior, i.e. lacking significant extended radio emission. Such sources form
the bulk of the population of radio-loud AGN in the Sloan Digital Sky Survey.
At a given level of nuclear emission, one can find radio sources with an
extremely wide range, a factor of >~100, of radio power. We argue that the
prevalence of sources with luminous extended radio structures in flux limited
samples is due to a selection bias, since the inclusion of such objects is
highly favored. The most studied catalogues of radio galaxies are thus composed
by the minority of radio-loud AGN that meet the physical conditions required to
form extended radio sources, while the bulk of the population is virtually
unexplored.Comment: 15 pages. Accepted for publication in A&
Evapotranspiration and water use efficiency in relation to climate and canopy nitrogen in U.S. forests
Understanding relations among forest carbon (C) uptake and water use is critical for predicting forest-climate interactions. Although the basic properties of tree-water relations have long been known, our understanding of broader-scale patterns is limited by several factors including (1) incomplete understanding of drivers of change in coupled C and water fluxes and water use efficiency (WUE), (2) difficulty in reconciling WUE estimates obtained at different scales, and (3) uncertainty in how evapotranspiration (ET) and WUE vary with other important resources such as nitrogen (N). To address these issues, we examined ET, gross primary production (GPP), and WUE at 11 AmeriFlux sites across North America. Our analysis spanned leaf and ecosystem scales and included foliar δ13C, δ18O, and %N measurements; eddy covariance estimates of GPP and ET; and remotely sensed estimates of canopy %N. We used flux data to derive ecosystem WUE (WUEe) and foliar δ13C to infer intrinsic WUE. We found that GPP, ET, and WUEe scaled with canopy %N, even when environmental variables were considered, and discuss the implications of these relationships for forest-atmosphere-climate interactions. We observed opposing patterns of WUE at leaf and ecosystem scales and examined uncertainties to help explain these opposing patterns. Nevertheless, significant relationship between C isotope-derived ci/ca and GPP indicates that δ13C can be an effective predictor of forest GPP. Finally, we show that incorporating species functional traits—wood anatomy, hydraulic strategy, and foliar %N—into a conceptual model improved the interpretation of Δ13C and δ18O vis-à -vis leaf to canopy water-carbon fluxes
Profound structural conservation of chemically cross-linked HIV-1 envelope glycoprotein experimental vaccine antigens.
Chemical cross-linking is used to stabilize protein structures with additional benefits of pathogen and toxin inactivation for vaccine use, but its use has been restricted by the potential for local or global structural distortion. This is of particular importance when the protein in question requires a high degree of structural conservation for inducing a biological outcome such as the elicitation of antibodies to conformationally sensitive epitopes. The HIV-1 envelope glycoprotein (Env) trimer is metastable and shifts between different conformational states, complicating its use as a vaccine antigen. Here we have used the hetero-bifunctional zero-length reagent 1-Ethyl-3-(3-Dimethylaminopropyl)-Carbodiimide (EDC) to cross-link two soluble Env trimers, selected well-folded trimer species using antibody affinity, and transferred this process to good manufacturing practice (GMP) for experimental medicine use. Cross-linking enhanced trimer stability to biophysical and enzyme attack. Cryo-EM analysis revealed that cross-linking retained the overall structure with root-mean-square deviations (RMSDs) between unmodified and cross-linked Env trimers of 0.4-0.5 Å. Despite this negligible distortion of global trimer structure, we identified individual inter-subunit, intra-subunit, and intra-protomer cross-links. Antigenicity and immunogenicity of the trimers were selectively modified by cross-linking, with cross-linked ConS retaining bnAb binding more consistently than ConM. Thus, the EDC cross-linking process improves trimer stability whilst maintaining protein folding, and is readily transferred to GMP, consistent with the more general use of this approach in protein-based vaccine design
ESMValTool (v1.0) – a community diagnostic and performance metrics tool for routine evaluation of Earth system models in CMIP
A community diagnostics and performance metrics tool for the evaluation of Earth system models (ESMs) has been developed that allows for routine comparison of single or multiple models, either against predecessor versions or against observations. The priority of the effort so far has been to target specific scientific themes focusing on selected essential climate variables (ECVs), a range of known systematic biases common to ESMs, such as coupled tropical climate variability, monsoons, Southern Ocean processes, continental dry biases, and soil hydrology–climate interactions, as well as atmospheric CO2 budgets, tropospheric and stratospheric ozone, and tropospheric aerosols. The tool is being developed in such a way that additional analyses can easily be added. A set of standard namelists for each scientific topic reproduces specific sets of diagnostics or performance metrics that have demonstrated their importance in ESM evaluation in the peer-reviewed literature. The Earth System Model Evaluation Tool (ESMValTool) is a community effort open to both users and developers encouraging open exchange of diagnostic source code and evaluation results from the Coupled Model Intercomparison Project (CMIP) ensemble. This will facilitate and improve ESM evaluation beyond the state-of-the-art and aims at supporting such activities within CMIP and at individual modelling centres. Ultimately, we envisage running the ESMValTool alongside the Earth System Grid Federation (ESGF) as part of a more routine evaluation of CMIP model simulations while utilizing observations available in standard formats (obs4MIPs) or provided by the user
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