Swarm-intelligent foraging in honeybees: benefits and costs of task-partitioning and environmental fluctuations

For honeybee colonies, it is crucial to collect nectar in an efficient way. Empiric experiments showed that the process of decision making, which allows the colony to select the optimal nectar source, is based on individual decisions. These decisions are made by returning nectar foragers, which alter their dancing behaviours based on the nectar source’s quality and based on the experienced search time for a receiver bee. Nectar receivers, which represent a shared limited resource for foragers, can modulate the foraging decisions performed by the colony. We investigated the interplay between foragers and receivers by using a multi-agent simulation. Therefore, we implemented agents which are capable of a limited set of behaviours and which spend energy according to their behaviour. In simulation experiments, we tested colonies with various receiver-to-forager ratios and measured colony-level results like the emerging foraging patterns and the colony’s net honey gain. We show that the number of receivers prominently regulates the foraging workforce. All tested environmental fluctuations are predicted to cause energetic costs for the colony. Task-partitioning additionally influences the colony’s decision-making concerning the question whether or not the colony sticks to a nectar source after environmental fluctuations.     

Synthetic Modular Antibody Construction by Using the SpyTag/SpyCatcher Protein-Ligase System

Efforts to engineer recombinant antibodies for specific diagnostic and therapy applications are time consuming and expensive, as each new recombinant antibody needs to be optimized for expression, stability, bio-distribution, and pharmacokinetics. We have developed a new way to construct recombinant antibody-like “devices” by using a bottom-up approach to build them from well-behaved discrete recombinant antibody domains or “parts”. Studies on antibody structure and function have identified antibody constant and variable domains with specific functions that can be expressed in isolation. We used the SpyTag/SpyCatcher protein ligase to join these parts together, thereby creating devices with desired properties based on summed properties of parts and in configurations that cannot be obtained by using genetic engineering. This strategy will create optimized recombinant antibody devices at reduced costs and with shortened development times.     

Discussion

In this discussion, we give a short overview of some of the uses of artificial neural networks in practice. This is not intended to be an exhaustive list, but it includes some widely used industrial examples with which we are familiar. From our experience, we also attempt to point out why they are used and what the relative advantages and disadvantages of using a neural network over a traditional statistical method might be.     

Mikrostrukturielle Charakterisierung von ultra-hochfesten Schweißgütern

Welded steel structures are a crucial part of lightweight constructions in several industrial segments. The filler metal plays a vital role in optimizing the properties of welded joints. In this study different methods were used to characterize the microstructure of ultra-high strength all-weld metal samples with different chemical compositions. It was evaluated which method can be used to link the grain size of a sample to its toughness.     

Theory and practice of the shifted Lotka function

One of the major drawbacks of the classical Lotka function is that arguments only start from the value 1. However, in many applications one may want to start from the value 0, e.g. when including zero received citations. In this article we consider the shifted Lotka function, which includes the case of zero items. Basic results for the total number of sources, the total number of items and the average number of items per source are given in this framework. Next we give the rank-frequency function (Zipf-type function) corresponding to the shifted Lotka function and prove their exact relation. The article ends with a practical example which can be fitted by a shifted Lotka function.     

Path to Market for Compact Modular Fusion Power Cores

The benefits of an energy source whose reactants are plentiful and whose products are benign is hard to measure, but at no time in history has this energy source been more needed. Nuclear fusion continues to promise to be this energy source. However, the path to market for fusion systems is still regularly a matter for long-term (20?+?year) plans. This white paper is intended to stimulate discussion of faster commercialization paths, distilling guidance from investors, utilities, and the wider energy research community (including from ARPA-E). There is great interest in a small modular fusion system that can be developed quickly and inexpensively. A simple model shows how compact modular fusion can produce a low cost development path by optimizing traditional systems that burn deuterium and tritium, operating not only at high magnetic field strength, but also by omitting some components that allow for the core to become more compact and easier to maintain. The dominant hurdles to the development of low cost, practical fusion systems are discussed, primarily in terms of the constraints placed on the cost of development stages in the private sector. The main finding presented here is that the bridge from DOE Office of Science to the energy market can come at the Proof of Principle development stage, providing the concept is sufficiently compact and inexpensive that its development allows for a normal technology commercialization path.     

Thermal Degradation and Ignition Characteristics of Clothes Dryer Lint

Lint, which is a normal by-product of the laundering of clothing, is known to introduce a fire hazard and/or contribute to the fuel load in residential fires. Failure analysis of clothes dryers therefore requires an understanding of how dryer lint behaves at elevated temperatures and how the physical condition of lint can be interpreted when testing for potential failure modes. The purpose of this research is to characterize the behavior of dryer lint at elevated temperatures, including its thermal degradation and ignition.