A guidance for assessing and communicating uncertainties.

In the daily practice of science for policy, as experienced by governmental agencies which inform the policy and the public on the state and outlook of the environment, there is a pressing need for guidance in assessing and communicating uncertainties. This need extends beyond the quantitative assessment of uncertainties in model results, and focuses on the entire process of environmental assessment, running from problem framing towards reporting the results of the study. Using the Netherlands Environmental Assessment Agency (RIVM/MNP) as a case, the development, structure and content of such a guidance system is highlighted. Conditions for a successful implementation of the guidance system are discussed, and some prospects for future work are outlined.     

Using the W&H integrated uncertainty analysis framework with non-initiated experts.

The W&H (Walker and Harremo?s) integrated uncertainty analysis framework was put forward with the aim of providing a conceptual basis for the systematic treatment of uncertainty in model-based decision support activities such as policy analysis, integrated assessment and risk assessment. It provides a heuristic tool that can be applied in decision support exercises to classify and report the various dimensions of uncertainty. The intention is to stimulate better communication among analysts as well as between them and policymakers and stakeholders. The framework successfully articulates diverse scholarly understandings of 'uncertainty', 'ignorance', and 'quality' in science for policy, Nevertheless, experience with the W&H framework has revealed that many of the concepts put forward are relatively unfamiliar--and perhaps somewhat controversial--to experts practising decision support. Thus, efforts are required to communicate the W&H framework to experts in such a way that their knowledge of uncertainty is elicited adequately, without them being overly intimidated or confused by the novelty of the concepts presented to them. After introducing the W&H conceptual framework, this paper presents the methodology that was used in applying the W&H framework in expert elicitations on uncertainty in the risk assessment of genetically modified crops. Experiences with the use of this methodology are discussed and recommendations for further improvement are given.     

One-sided tests in shared frailty models

Tests for the presence of heterogeneity in frailty models use an alternative hypothesis in which the heterogeneity parameter is subject to an inequality constraint. As a result, the classical likelihood ratio asymptotic chi-square distribution theory is no longer valid. Our main result states the limiting distribution of the likelihood ratio and score statistic for the one-sided testing problem. The resulting distribution is a mixture of chi-square distributed random variables. The results are shown for gamma and positive stable frailty distributions, and hold when covariate information is present. A data example illustrates the tests. We also assess, in a simulation study, the performance of the tests regarding the significance level and power.      

Analysis of InP Regrowth on Deep-Etched Mesas and Structural Characterization for Buried-Heterostructure Quantum Cascade Lasers

We investigated the effect of deep-etched mesa sidewall profile and oxide overhang length on the regrowth structural characteristics for buried- heterostructure (BH) quantum cascade lasers (QCLs) grown by metalorganic chemical vapor deposition (MOCVD). The relationship between etched mesa sidewall geometry, oxide overhang length, oxide thickness, and growth uniformity was examined and is extensively discussed. In particular, anomalous growth in the vicinity of the oxide edge resulting from insufficient oxide overhang length was identified and studied. An ideal ratio of mesa height to oxide overhang length between 2.5 and 3.0 is proposed and experimentally justified to yield satisfactory planar regrowths without anomalous growth. Mesas in the [ 0 1[` 1] ] [ 0 1\overline{ 1} ] direction with smoothly etched entrant profile yield a higher degree of growth uniformity than mesas in the [011] direction with the re-entrant profile.     

Exciton formation and light emission near the organic–organic interface in small-molecule based double-layer OLEDs

We investigate the efficiency and emission color of small-molecule based double-layer organic light-emitting diodes (OLEDs) based on 4,4′-bis[1-naphthyl (phenyl) amino]-1,1′-biphenyl (α-NPD) and aluminum (III) bis (2-methyl-8-quinolinato)4-phenylphenolato (BAlq) by studying the charge transport and photophysics near the organic–organic interface between the emitting layers. For that purpose, the light-emission profile is reconstructed from full angle, wavelength and polarization dependent electroluminescence spectra. By increasing the thickness of the BAlq layer from 100 to 300 nm, at a fixed 160 nm α-NPD layer thickness, the emission color is found to vary from deep blue to green, yellow-green, white and back to blue. We demonstrate that this is due to a gradual emission profile shift, in combination with a wavelength and layer thickness dependent light outcoupling efficiency. The emission profile shift, from an approximately 20 nm-wide zone on the α-NPD-side of the interface to a very narrow zone on the BAlq-side of the interface, gives rise to a changing balance between the contributions from BAlq excitons, α-NPD excitons and charge-transfer excitons. It also contributes to a pronounced layer thickness dependence of the external quantum efficiency. The shift of the emission profile is explained by a charge transport and recombination model.     

Autocoro上纺聚酯纱

介绍了Schlafhorst公司设计的、用于Autocoro纺纱机上的新型部件。通过测试，证明纤维上的纺丝助剂对纺纱性能的影响。     

Efficient Tandem Biocatalytic Process for the Kinetic Resolution of Aromatic β‐Amino Acids

We describe a simple and efficient enzymatic tandem reaction for the preparation of enantiomerically pure β‐phenylalanine and its analogues from the corresponding racemates. In this process, phenylalanine aminomutase (PAM) catalyzes the stereoselective isomerization of (R)‐β‐phenylalanines to (S)‐α‐phenylalanines, which are in situ transformed to cinnamic acids by phenylalanine ammonia lyase (PAL). Preparative scale conversions are done with a mutated PAM with enhanced catalytic activity.     

Pheromone-Induced Priming of a Defensive Response in Western Flower Thrips

The Western flower thrips Frankliniella occidentalis produces conspicuous anal droplets that function as a direct defense against various predators. These droplets also function in pheromonal communication in that they contain a mixture of decyl acetate and dodecyl acetate, which acts as an alarm. Exposure of thrips to synthetic pheromone is known to promote takeoff or refuge seeking, but the effect of the natural pheromone has not yet been studied. Here, we not only studied the response to natural pheromone, but also tested the new hypothesis that the alarm pheromone primes a defensive response in thrips. This test was carried out by measuring the reaction time to a simulated predator attack after exposure to synthetic or natural alarm pheromone (against a control with no pheromone at all). The reaction was quantified in terms of the time it takes a thrips larva to produce a droplet after attack. We found that thrips larvae produce droplets of alarm pheromone faster when cues associated with danger are present. There were no significant differences in reaction times of responses to synthetic pheromone, natural pheromone, or odors from a patch with a predator attacking a thrips larva. This implies that the synthetic pheromone mimics the natural pheromone, and that other cues emanating from the predator play a minor role. We conclude that the alarm pheromone increases the vigilance of the thrips, and this may promote its survival.An erratum to this article can be found at