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The generation of haploids is one of the most powerful means to accelerate the plant breeding process. In most crop species, an efficient haploid technology is not yet available or only applicable to a limited set of genotypes. Recent results published forArabidopsis thalianaand major cereal crops like maize and wheat about successful haploid induction by CRISPR/Cas9-mediated editing of the centromeric histone H3 gene (CENH3) suggest that this novel method for the production of haploid plants might also be applicable to vegetable species like carrot. Here, we report and summarize the different experimental and genetic approaches that have been focused in the past few years on CRISPR/Cas9-based editing of the carrot CENH3 gene. We also describe the discovery of a second CENH3 locus in the carrot genome, which complicates the attempts to generate and to analyse putative haploid inducer genotypes. We show that three different CRISPR/Cas9 target constructs, used alone or in combinations, could successfully target carrot CENH3. Promising mutants such as in-frame indel or in-frame deletion mutants have been found, but their successful usage as putative haploid inducer is uncertain yet. Next generation sequencing of amplicons spanning CRISPR target sites and transcript-based amplicon sequencing seemed to be appropriate methods to select promising mutants, to estimate mutation frequencies, and to allow a first prediction which gene was concerned. Another aim of this study was the simultaneous knockout and complementation of the endogenous carrot CENH3 gene by an alien CENH3 gene. Co-transformation of a CRISPR/Cas9-based carrot CENH3 knockout construct together with a CENH3 gene cloned from ginseng (Panax ginseng) was performed by usingRhizobium rhizogenes. It was shown, that ginseng CENH3 protein is accumulated inside the kinetochore region of carrot chromosomes, indicating thatPgCENH3might be a suited candidate for this approach. However, presently it is unclear, if this gene is fully functioning during the meiotic cell divisions and able to complement lethal gametes. Challenges and future prospects to develop a CENH3-based HI system for carrot are discussed.

The Dial-a-Ride Problem (DARP) aims to find a set of minimal cost tours for passenger vehicles in order to satisfy a set of transport requests. Each request requires to pick up one or more passengers at a defined pick-up point and then drop off the passengers at the desired destination. In this work, we consider a DARP that has been implemented for an Austrian mobility provider. The company focuses on rural regions that suffer from insufficient public transportation and offers a sustainable form of mobility. The provider is especially interested in improving the sharing rates of the mobility service. Therefore, we propose a Large Neighborhood Search for solving the respective DARP. In a computational study, we compare different configurations of the service and identify the most promising configurations regarding sharing rates, passenger convenience and, hence, the overall efficiency of the service.

Today’s world is fast-paced and so is technology. Almost every little device is somehow ”smart”, i.e., it collects data and provides some features. In order to cope with this development, the need for efficient optimization techniques grows steadily. In this work, we consider the maintenance process of smart meter devices, i.e., devices that collect data about electricity consumption. These smart meters are installed in private homes and need to be maintained from time to time. The maintenance is conducted by service operators of electricity companies. Since house owners have to be informed about the service at least two weeks prior, the procedure of planning shifts can be performed in advance. We develop and compare two solution approaches for determining shifts for service operators and evaluate the performance and stability of the generated tours with different metrics.

The steadily growing popularity of grocery home-delivery services is most likely based on the convenience experienced by its customers. However, the perishable nature of the products imposes certain requirements during the delivery process. The customer must be present when the delivery arrives so that the delivery process can be completed without interrupting the cold chain. Therefore, the grocery retailer and the customer must mutually agree on a time window during which the delivery can be guaranteed. This concept is referred to as the attended home delivery (AHD) problem in the scientific literature. The phase during which customers place orders, usually through a web service, constitutes the computationally most challenging part of the logistical processes behind such services. The system must determine potential delivery time windows that can be offered to incoming customers and incrementally build the delivery schedule as new orders are placed. Typically, the underlying optimization problem is a vehicle routing problem with a time windows. This work is concerned with a case given by an international grocery retailer’s online shopping service. We present an analysis of several efficient solution methods that can be employed to AHD services. A framework for the operational planning tools required to tackle the order placement process is provided. However, the basic framework can easily be adapted to be used for many similar vehicle routing applications. We provide a comprehensive computational study comparing several algorithmic strategies, combining heuristics utilizing local search operations and mixed-integer linear programs, tackling the booking process. Finally, we analyze the scalability and suitability of the approaches.

We consider a new facility layout problem. The Directed Circular Facility Layout Problem (DCFLP) seeks to optimally arrange machines on a circular layout with given material flow direction. The DCFLP allows for a wide range of applications and contains several other relevant layout problems as special cases. We model the DCFLP as a Linear Ordering Problem and solve it using an Integer Linear Program and a Tabu Search heuristic. In our computational study we show that the DCFLP is easier to solve for both exact and heuristic approaches than other related layout problems.

This case study aims at presenting the business model and the results of the Santander International Entrepreneurship Centre (CISE), an international reference Centre dedicated to fostering entrepreneurship and promoting the generation of start-ups. It provides a brief introduction into the Centre’s context and stresses CISE’s history and institutional set-up; this is followed by a presentation of its mission and vision on which its programmes and activities are based. It then highlights the Centre’s distinctive comprehensive entrepreneurship and multi-stakeholder approach and provides insight into CISE’s innovative training and support programmes. This case study concludes that it is possible to establish comprehensive strategies in support of an entrepreneurial culture through functional planning and coordination with own and other stakeholders’ initiatives.

Many neurons adapt their spike output to accommodate the prevailing sensory environment. Although such adaptation is thought to improve coding of relevant stimulus features, the relationship between adaptation at the neural and behavioral levels remains to be established. Here we describe improved discrimination performance for an auditory spatial cue (interaural time differences, ITDs) following adaptation to stimulus statistics. Physiological recordings in the midbrain of anesthetized guinea pigs and measurement of discrimination performance in humans both demonstrate improved coding of the most prevalent ITDs in a distribution, but with highest accuracy maintained for ITDs corresponding to frontal locations, suggesting the existence of a fovea for auditory space. A biologically plausible model accounting for the physiological data suggests that neural tuning is stabilized by inhibition to maintain high discriminability for frontal locations. The data support the notion that adaptive coding in the midbrain is a key element of behaviorally efficient sound localization in dynamic acoustic environments.

In order to investigate whether performance in an auditory spatial discrimination task depends on the prevailing listening conditions, we tested the ability of human listeners to discriminate target sounds with and without presentation of a preceding sound. Target sounds were either lateralized by means of interaural time differences (ITDs) of +400, 0, or -400 micros or interaural level differences (ILDs) with the same subjective intracranial locations. The preceding sound was always lateralized by means of ITD. This allowed for testing whether the effects of a preceding sound were location- or cue-specific. Preceding sounds and target sounds were randomly paired across trials. Listeners had to discriminate whether they perceived the target sounds as coming from the same or different intracranial locations. Finally, stimuli were selected so that, without any preceding sound, ITD and ILD cues were equally discriminable at all target lateralizations. Stimuli were 800 Hz-wide, 400-ms duration bands of noise centered at 500 Hz, presented over headphones. The duration of the preceding sound was randomly selected from a uniform distribution spanning from 1s to 2s. Results show that discriminability of both binaural cues was improved for midline target positions when preceding sound and targets were co-located, whereas it was impaired when preceding sound and targets came from different positions. No effect of the preceding sound was found for left or right target positions. These results are compatible with a purely bottom-up mechanism based on adaptive coding of ITD around the midline that may be combined with top-down mechanisms to increase localization accuracy in realistic listening conditions.

In a study published previously in this journal (Wilkinson et al., 2002), the effect of chewing gum on cognitive functioning was examined. The results of this study indicated that chewing a piece of gum results in an improvement of working memory and of both immediate and delayed recall of words but not of attention. In the present study, memory and a variety of attentional functions of healthy adult participants were examined under four different conditions: no chewing, mimicking chewing movements, chewing a piece of tasteless chewing gum and chewing a piece of spearmint flavoured chewing gum. The sequence of conditions was randomised across participants. The results showed that the chewing of gum did not improve participants' memory functions. Furthermore, chewing may differentially affect specific aspects of attention. While sustained attention was improved by the chewing of gum, alertness and flexibility were adversely affected by chewing. In conclusion, claims that the chewing a gum improves cognition should be viewed with caution.