Marker development in ornamental plants

Development of markers for a new crop or development of additional markers for a crop where markers have been developed in the past raises the question of the intended use of the markers. Depending on the different objectives in mind one marker type may be better suited then another. In general one can think of two main objectives for the use of markers; variety identification and breeding applications. In view of recent developments in molecular genetics, and sequencing technologies in particular, within the 23rd International Eucarpia Symposium Section Ornamentals a workshop was devoted on molecular markers and their use in ornamentals. Within this paper an overview will be presented on the development of markers for identification of ornamental crops and on the importance of the new developments in marker and sequence technology for the use of markers in ornamental breedin

Algorithmic Pricing:The Current State of Affairs from a Law and Economics Perspective

The rise of algorithmic pricing has transformed perfect price discrimination from a theoretical concept into a real possibility. Through self-learning pricingalgorithms, a strategy can be developed that approximates consumers’ reservation prices with ever-improving accuracy. This paper analyzes algorithmic pricing from a law and economics perspective to identify the efficiency and equity effects that the practice could cause and determine to which extent it is regulated under the current legal framework. This paper finds that under competitive market conditions, algorithmic pricing could be welcomed from an efficiency perspective, but from an equity and ethical perspective serious concerns need to be raised. If these concerns are to be taken seriously, the legal framework provides only a partially functional approach to address algorithmic pricing. Additional appropriate remedies are, therefore, needed to protect consumers adequately and effectively against exploitation that reduces their welfare

Perception, Action, and Sense Making:The Three Realms of the Aesthetic

It is argued that Kull’s approach to aesthetics complements a cognitive semiotic approach to culture. The concept of ‘ecological, semiotic fitting’ allows us to connect the three main concepts of beauty we encounter in discussions about the aesthetic, where the term beauty is, firstly, used to refer a positive experience in relation to what is perceived, or, secondly, to a positive experience in relation to an intentional action or, thirdly, to a positive experience in relation to a sense making process. Kull makes a strong case for the ‘ecological, semiotic fitting’ being the common underlying structure of all three manifestations of the aesthetic

ps2, the gene responsible for functional sterility in tomato, due to non-dehiscent anthers, is the result of a mutation in a novel polygalacturonase gene

The recessive mutation ps-2, which appeared spontaneously in tomato, confers functional male sterility due to non-dehiscent anthers. In this study, we isolated and characterized the PS-2 gene. A single nucleotide mutation in a novel tomato polygalacturonase gene is responsible for the ps-2 phenotype. The mutation in ps-2 is responsible for an alternative splicing during maturation of the pre-mRNA, which leads to an aberrant mRNA. Differentiation between ps-2 and wild type (PS-2) anthers only appears in the final developmental stage in which the stomium remains closed in the mutant. To our knowledge, this is the first functional sterility gene isolated in the Solanaceae family. The specific expression of the Arabidopsis homolog of PS-2 in the anther dehiscence zone suggests a conserved mode of action over the plant kingdom, which means that the repression of PS-2 homologs may be a potential way to introduce functional sterility in other specie

Keeping an Eye on the Periphery:How Eccentricity affects Visual Selection

After reading the work of this thesis I hope you are convinced that eccentricity is a major factor that cannot be ignored when it comes to understanding visual selection. More specifically, in Chapter 2 we showed that while the proportion of selecting targets and salient items does not change with eccentricity, the dynamics of saliency- and relevance-driven selection do change. That is, the effect of saliency was protracted at a further eccentricity, while the effect of relevance was delayed. This discrepancy between overall selection and performance over time can be explained by the difference in saccade latencies between conditions. That is, as the saccade latency distribution shifted in time with increasing eccentricity, so did the effects of saliency and relevance. In Chapter 3, consistent with earlier work, we challenged existing models of visual selection, showing that the time at which a saccade is initiated greatly influences whether it will be saliency- or relevance-driven. That is, short latency eye movements are more likely to be saliency driven while later eye movements are more likely to be relevance driven. Importantly, we showed for the first time that this separation in time leads to a brief period in between saliency-driven and relevance-driven selection in which the eyes appear to be in ‘limbo’. That is, selection appears to operate randomly, irrespective of saliency and relevance. By fitting different models on the data, we showed that the dynamics of saliency- and relevance-based selection are best described as two independent processes that do not influence each other. We propose an alternative view on the classic priority map model, in which saliency effects are actually a byproduct of a difference in processing speed between different items. That is, on the priority map, salient items are available for selection earlier than non-salient items as they are processed more quickly and elicit therefore more activation at an earlier point in time. After a while, this difference in activation disappears because then non-salient items are processed as well, resulting in a period of non-selectivity. After this, the influence of behavioral relevance takes effect, and activity for the relevant item increases. In Chapter 4 we showed that subjects are more likely to select items that are presented close to fixation than items presented further away. This central selection bias was larger than would be expected based on low-level sensory differences between eccentricities suggesting an important role for attentional competition. In Chapter 5 we were able to determine, for the first time, the time course that the effect of eccentricity follows. Here we showed that eccentricity mainly influences those saccades that are initiated early. That is, eccentricity operates in a similar time window as saliency. As a consequence, the effects of saliency were diminished as the eccentricity difference between the two items grew, but those of relevance were unaffected. In Chapter 6 we showed that attentional capture by salient distractors is modulated by the bias that is described in Chapter 4. That is, even though we saw no effect of eccentricity on attentional capture in overall manual RTs, using eye movement data we showed that participants are more likely to select an item closer to fixation than an item presented further away. Crucially, on those trials in which an eye movement was made towards the distractor reaction times increased with distractor eccentricity while the likelihood of making an eye movement to the distractor in the first place decreases with increasing distractor eccentricity. As these effects go in opposite directions, overall RT showed no effect of distractor eccentricity when all trials were combined together

Data-Driven Safety Filter: An Input-Output Perspective

Implementation of learning-based control remains challenging due to the absence of safety guarantees. Safe control methods have turned to model-based safety filters to address these challenges, but this is paradoxical when the ultimate goal is a model-free, data-driven control solution. Addressing the core question of "Can we ensure the safety of any learning-based algorithm without explicit prediction models and state estimation?" this paper proposes a Data-Driven Safety Filter (DDSF) grounded in Behavioral System Theory (BST). The proposed method needs only a single system trajectory available in an offline dataset to modify unsafe learning inputs to safe inputs. This contribution addresses safe control in the input-output framework and therefore does not require full state measurements or explicit state estimation. Since no explicit model is required, the proposed safe control solution is not affected by unmodeled dynamics and unstructured uncertainty and can provide a safe solution for systems with unknown time delays. The effectiveness of the proposed DDSF is illustrated in simulation for a high-order six-degree-of-freedom aerial robot and a time-delay adaptive cruise control system

Do the Herschel cold clouds in the Galactic halo embody its dark matter?

Recent Herschel/SPIRE maps of the Small and Large Magellanic Clouds (SMC, LMC) exhibit in each thousands of clouds. Observed at 250 microns, they must be cold, T ~ 15 K, hence the name "Herschel cold clouds" (HCCs). From the observed rotational velocity profile and the assumption of spherical symmetry, the Galactic mass density is modeled in a form close to that of an isothermal sphere. If the HCCs constitute a certain fraction of it, their angular size distribution has a specified shape. A fit to the data deduced from the SMC/LMC maps supports this and yields for their radius 2.5 pc, with a small change when allowing for a spread in HCC radii. There are so many HCCs that they will make up all the missing Halo mass density if there is spherical symmetry and their average mass is of order 15,000 Mo. This compares well with the Jeans mass of circa 40,000 Mo and puts forward that the HCCs are in fact Jeans clusters, constituting all the Galactic dark matter and much of its missing baryons, a conclusion deduced before from a different field of the sky (Nieuwenhuizen, Schild and Gibson 2011). A preliminary analysis of the intensities yields that the Jeans clusters themselves may consist of some billion MACHOs of a few dozen Earth masses. With a size of dozens of solar radii, they would mostly obscure stars in the LMC, SMC and towards the Galactic center, and may thus have been overlooked in microlensing.Comment: Revised and corrected version, matches published version. Conclusions unchange