The role of regulatory mechanisms for control of plant diseases and food security — case studies from potato production in Britain

Being aware of the potentially devastating impacts of plant diseases on food security, governments have designed and employ plant health legislation to prevent or inhibit the worst impacts. The development of such policies in Britain, and latterly in Europe, can be closely linked to disease events that have occurred in the potato sector. We analyse early and current examples of policies governing potato diseases in Britain to identify the decision processes leading to the implementation of such phytosanitary policies and how they have evolved over time and in response to different disease threats. Reasons for developing and implementing phytosanitary policies include the desire to prevent pathogens being introduced (entering and establishing in a new area), the protection of export markets, and the lack of effective control measures. Circumstances in which regulatory policies would not be appropriate could include situations where a disease is already widely distributed, unacceptable costs, lack of exclusion measures, or difficulties of disease diagnosis. We conclude that in general, government policies have worked well in protecting British potato growing over the last one hundred years, despite of the failures of some of the policies discussed here. They have also contributed much to the development of plant health policies for other crops. Voluntary grower initiatives are a new mechanism complementing existing formal policies with an additional level of security that allows individual growers to take on additional responsibility rather than relying entirely on government legislation

Novel Measurement Technique of the Tibial Slope on Conventional MRI

The posterior inclination of the tibial plateau, which is referred to as posterior tibial slope, is determined routinely on lateral radiographs. However, radiographically, it is not always possible to reliably recognize the lateral plateau, making a separate assessment of the medial and lateral plateaus difficult. We propose a technique to measure the plateaus separately by defining a tibial longitudinal axis on a conventional MRI. The medial plateau posterior tibial slope obtained from radiographs was compared with MR images in 100 consecutive patients with knee pain when ligament or meniscal injury was assumed. The posterior tibial slope on MRI correlated with those on radiographs. The mean posterior tibial slope was 3.4° smaller on MRI compared with radiographs (4.8°±2.4° versus 8.2°±2.8°, respectively). The reproducibility was slightly better on radiographs than MRI (±0.9° versus±1.4°). Twenty-one of the 100 cases had more than a 5° difference (range, −8.7° to 8.9°) between the medial and lateral plateaus. The proposed technique allows measurement of the posterior tibial slope of the medial and lateral plateaus on a standard knee MRI. By using this novel measurement technique, a reliable assessment of the medial and lateral tibial plateaus is possible. Level of Evidence: Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidenc

Influence of the Precipitating Energetic Particles on Atmospheric Chemistry and Climate

We evaluate the influence of the galactic cosmic rays (GCR), solar proton events (SPE), and energetic electron precipitation (EEP) on chemical composition of the atmosphere, dynamics, and climate using the chemistry-climate model SOCOL. We have carried out two 46-year long runs. The reference run is driven by a widely employed forcing set and, for the experiment run, we have included additional sources of NO x and HO x caused by all considered energetic particles. The results show that the effects of the GCR, SPE, and EEP fluxes on the chemical composition are most pronounced in the polar mesosphere and upper stratosphere; however, they are also detectable and statistically significant in the lower atmosphere consisting of an ozone increase up to 3% in the troposphere and ozone depletion up to 8% in the middle stratosphere. The thermal effect of the ozone depletion in the stratosphere propagates down, leading to a warming by up to 1K averaged over 46years over Europe during the winter season. Our results suggest that the energetic particles are able to affect atmospheric chemical composition, dynamics, and climat

Chemistry-climate model SOCOL: a validation of the present-day climatology

International audienceIn this paper we document ''SOCOL'', a new chemistry-climate model, which has been ported for regular PCs and shows good wall-clock performance. An extensive validation of the model results against present-day climate obtained from observations and assimilation data sets shows that the model describes the climatological state of the atmosphere for the late 1990s with reasonable accuracy. The model has a significant temperature bias only in the upper stratosphere and near the tropopause in the tropics and high latitudes. The latter is the result of the rather low vertical resolution of the model near the tropopause. The former can be attributed to a crude representation of the radiation heating in the middle atmosphere. A comparison of the simulated and observed link between the tropical stratospheric structure and the strength of the polar vortex shows that in general, both observations and simulations reveal a higher temperature and ozone mixing ratio in the lower tropical stratosphere for the case with stronger Polar night jet (PNJ) as predicted by theoretical studies

Usable error message presentation in the World Wide Web: Do not show errors right away

Online form validation can be performed in several ways. This article discusses two empirical studies with 77 and 90 participants, which have found evidence that the best way of presenting error messages is to provide the erroneous fields after users have completed the whole form. Immediate error feedback recommended by the International Organization for Standardization (ISO) showed the worst performance in these studies. Where presented with immediate feedback, users often simply ignored the messages on the screen and continued completing the form as if nothing happened. These results lead to the postulation of the "Modal Theory of Form Completion”: Users are in either "Completion” or "Revision Mode” when filling out online forms. These modes affect the users' way of interaction with the system: During Completion Mode the users' disposition to correct mistakes is reduced, therefore error messages are often ignore

Implications of potential future grand solar minimum for ozone layer and climate

Continued anthropogenic greenhouse gas (GHG) emissions are expected to cause further global warming throughout the 21st century. Understanding the role of natural forcings and their influence on global warming is thus of great interest. Here we investigate the impact of a recently proposed 21st century grand solar minimum on atmospheric chemistry and climate using the SOCOL3-MPIOM chemistry-climate model with an interactive ocean element. We examine five model simulations for the period 2000-2199, following the greenhouse gas concentration scenario RCP4.5 and a range of different solar forcings. The reference simulation is forced by perpetual repetition of solar cycle 23 until the year 2199. This reference is compared with grand solar minimum simulations, assuming a strong decline in solar activity of 3.5 and 6.5Wm−2, respectively, that last either until 2199 or recover in the 22nd century. Decreased solar activity by 6.5Wm−2 is found to yield up to a doubling of the GHG-induced stratospheric and mesospheric cooling. Under the grand solar minimum scenario, tropospheric temperatures are also projected to decrease compared to the reference. On the global scale a reduced solar forcing compensates for at most 15% of the expected greenhouse warming at the end of the 21st and around 25% at the end of the 22nd century. The regional effects are predicted to be significant, in particular in northern high-latitude winter. In the stratosphere, the reduction of around 15% of incoming ultraviolet radiation leads to a decrease in ozone production by up to 8%, which overcompensates for the anticipated ozone increase due to reduced stratospheric temperatures and an acceleration of the Brewer–Dobson circulation. This, in turn, leads to a delay in total ozone column recovery from anthropogenic halogen-induced depletion, with a global ozone recovery to the pre-ozone hole values happening only upon completion of the grand solar minimum

Mental models for web objects: Where do users expect to find the most frequent objects in online shops, news portals, and company web pages?

In interface development, it is crucial to reflect the users' expectations and mental models. By meeting users' expectations, errors can be prevented and the efficiency of the interaction can be enhanced. Applying these guidelines to website development reveals the need to know where users expect to find the most common web objects like the search field, home button or the navigation. In a preliminary online study with 136 participants, the most common web objects were identified for three web page types: online shops, news portals, and company web pages. These objects were used for the main study, which was conducted with 516 participants. In an online application, prototypical websites had to be constructed by the participants. Data analysis showed that Internet users have distinct mental models for different web page types (online shop, news portal, and company web page). Users generally agree about the locations of many, but not all, web objects. These mental models are robust to demographic factors like gender and web expertise. This knowledge could be used to improve the perception and usability of website

Chemistry-climate model SOCOL: a validation of the present-day climatology

In this paper we document 'SOCOL', a new chemistry-climate model, which has been ported for regular PCs and shows good wall-clock performance. An extensive validation of the model results against present-day climate data obtained from observations and assimilation data sets shows that the model describes the climatological state of the atmosphere for the late 1990s with reasonable accuracy. The model has a significant temperature bias only in the upper stratosphere and near the tropopause at high latitudes. The latter is the result of the rather low vertical resolution of the model near the tropopause. The former can be attributed to a crude representation of radiation heating in the middle atmosphere. A comparison of the simulated and observed link between the tropical stratospheric structure and the strength of the polar vortex shows that in general, both observations and simulations reveal a higher temperature and ozone mixing ratio in the lower tropical stratosphere for the case with stronger Polar night jet (PNJ) and slower Brewer-Dobson circulation as predicted by theoretical studies