Localised edge states nucleate turbulence in extended plane Couette cells

We study the turbulence transition of plane Couette flow in large domains where localised perturbations are observed to generate growing turbulent spots. Extending previous studies on the boundary between laminar and turbulent dynamics we determine invariant structures intermediate between laminar and turbulent flow. In wide but short domains we find states that are localised in spanwise direction, and in wide and long domains the states are also localised in downstream direction. These localised states act as critical nuclei for the transition to turbulence in spatially extended domains.Comment: 15 pages, 5 figure

Invasive species along road segments and recommendations for remediation

This literature review specifically looks at roads segments as facilitators for non-native invasive plant species. There are three types of roads presented throughout this paper; primary regionally paved roads; secondary local roads; and tertiary unpaved off-road segments. The goal is to review and recognize any predictable patterns of spread along these three types of roads, so that appropriate restoration efforts can be implemented. To review such a topic, several academic articles all containing a focus on invasive plant species along road corridors were gathered and organised into groups based on the type of road that was mentioned in the article. All the data covering species richness was organized into a table and analysed. Ultimately the results displayed that primary roads were the least successful at facilitating spread for invasive plant species and tertiary roads were most successful. Many variables like soil quality, temperature, traffic, etc. can provide explanation to why species richness is more abundant on tertiary roads than primary roads. Based on the compiled explanations from an array of literature, an appropriate conservation management technique such as leaving cuttings on site, cutting/ pulling invasive plants at a certain time as well as introducing wash stations on suitable site. This will encourage the reduction of unwanted invasion and ensure the efficiency of conservation practises

The effects of jasmonic acid and ethylenediamine-di-o-hydroxyphenyl-acetic acid on floral induction and induction of turions in Spirodela polyrhiza (L.) Schleiden

We investigated the effects of jasmonic acid (JA) and ethylenediamine-di-o-hydroxyphenyl- acetic acid (EDDHA) on floral induction and induction of turions in the photoperiodically neutral clone Djelekovec of the species Spirodela polyrhiza in axenical cultures. JA (0.475–47.5 nmol L–1) promoted floral induction under long-day (LD) and short-day (SD) conditions, while it had no effect on turion induction. The inhibitory effect of JA on flowering and turion induction was observed at a JA concentration of 237.5 nmol L–1 and 475 nmol L–1. Under the same conditions, flowering and induction of turions were enhanced by EDDHA (20.5 mmol L–1). The combination of EDDHA (20.5 mmol L–1) and JA (47.5 nmol L–1) had an additive effect on the promotion of floral induction, which was promoted significantly in experiments with LD preculture. The results obtained by quantitative determination of endogenous JA levels in Spirodela polyrhiza at two growth stages support our previous findings that JA may regulate floral induction. The levels of endogenous JA decreased from 226±12 ng g–1 fresh weight during the vegetative stage in LD to 38.1±3.5 ng g–1 in the flowering plants. In SD the levels of endogenous JA decreased from 62±9 ng g–1 fresh weight during vegetative stage to 29.2±3.1 ng g–1 in the flowering plants

Cutting corners: The impact of storage and DNA extraction on quality and quantity of DNA in honeybee (Apis mellifera) spermatheca

The purpose of our study was to investigate methods of short-term storage that allow preservation, transport and retrieval of genetic information contained in honeybee queen's spermatheca. Genotyping of the honeybee colony requires well ahead planned sample collection, depending on the type of data to be acquired. Sampling and genotyping of spermatheca's content instead of individual offspring is timesaving, allowing answers to the questions related to patriline composition immediately after mating. Such procedure is also cheaper and less error prone. For preservation either Allprotect Tissue Reagent (Qiagen) or absolute ethanol were used. Conditions during transportation were simulated by keeping samples 6-8 days at room temperature. Six different storing conditions of spermathecas were tested, complemented with two DNA extraction methods. We have analysed the concentration of DNA, RNA, and proteins in DNA extracts. We also analysed how strongly the DNA is subjected to fragmentation (through amplification of genetic markers ANT2 and tRNA(leu)-COX2) and whether the quality of the extracted DNA is suitable for microsatellite (MS) analysis. Then, we tested the usage of spermatheca as a source of patriline composition in an experiment with three instrumentally inseminated virgin queens and performed MS analysis of the extracted DNA from each spermatheca, as well as queens' and drones' tissue. Our results show that median DNA concentration from spermathecas excised prior the storage, regardless of the storing condition and DNA extraction method, were generally lower than median DNA concentration obtained from spermathecas dissected from the whole queens after the storage. Despite the differences in DNA yield from the samples subjected to different storing conditions there was no significant effect of storage method or the DNA extraction method on the amplification success, although fewer samples stored in EtOH amplified successfully in comparison to ATR storing reagent. However, we recommend EtOH as a storing reagent due to its availability, low price, simplicity in usage in the field and in the laboratory, and capability of good preservation of the samples for DNA analysis during transport at room temperature

DeepCABAC: A Universal Compression Algorithm for Deep Neural Networks

The field of video compression has developed some of the most sophisticated and efficient compression algorithms known in the literature, enabling very high compressibility for little loss of information. Whilst some of these techniques are domain specific, many of their underlying principles are universal in that they can be adapted and applied for compressing different types of data. In this work we present DeepCABAC, a compression algorithm for deep neural networks that is based on one of the state-of-the-art video coding techniques. Concretely, it applies a Context-based Adaptive Binary Arithmetic Coder (CABAC) to the network's parameters, which was originally designed for the H.264/AVC video coding standard and became the state-of-the-art for lossless compression. Moreover, DeepCABAC employs a novel quantization scheme that minimizes the rate-distortion function while simultaneously taking the impact of quantization onto the accuracy of the network into account. Experimental results show that DeepCABAC consistently attains higher compression rates than previously proposed coding techniques for neural network compression. For instance, it is able to compress the VGG16 ImageNet model by x63.6 with no loss of accuracy, thus being able to represent the entire network with merely 8.7MB. The source code for encoding and decoding can be found at https://github.com/fraunhoferhhi/DeepCABAC