Mutations in shaking-B prevent electrical synapse formation in the Drosophila giant fiber system

The giant fiber system (GFS) is a simple network of neurons that mediates visually elicited escape behavior in Drosophila. The giant fiber (GF), the major component of the system, is a large, descending interneuron that relays visual stimuli to the motoneurons that innervate the tergotrochanteral jump muscle (TTM) and dorsal longitudinal flight muscles (DLMs). Mutations in the neural transcript from the shaking-B locus abolish the behavioral response by disrupting transmission at some electrical synapses in the GFS. This study focuses on the role of the gene in the development of the synaptic connections. Using an enhancer-trap line that expresses lacZ in the GFs, we show that the neurons develop during the first 30 hr of metamorphosis. Within the next 15 hr, they begin to form electrical synapses, as indicated by the transfer of intracellularly injected Lucifer yellow. The GFs dye-couple to the TTM motoneuron between 30 and 45 hr of metamorphosis, to the peripherally synapsing interneuron that drives the DLM motoneurons at approximately 48 hr, and to giant commissural interneurons in the brain at approximately 55 hr. Immunocytochemistry with shaking-B peptide antisera demonstrates that the expression of shaking-B protein in the region of GFS synapses coincides temporally with the onset of synaptogenesis; expression persists thereafter. The mutation shak-B2, which eliminates protein expression, prevents the establishment of dye coupling shaking-B, therefore, is essential for the assembly and/or maintenance of functional gap junctions at electrical synapses in the GFS

Brexit is changing the scenario for private equity in the UK

There are both threats and opportunities for private equity firms and their portfolio companies, write Mike Wright, Kevin Amess, Nick Bacon, John Gilligan and Nick Wilso

Geographic origin of migratory birds based on stable isotope analysis: the case of the greylag goose (Anser anser) wintering in Camargue, southern France

International audienceProper delineation of flyways is a prerequisite for adequate management of migratory birds. The implementation of coordinated international management for greylag goose (Anser anser) is currently underway in Europe for the north-west/south-west (NW/ SW) population. Some uncertainty remained as to whether greylags wintering in Camargue, Southern France, belonged to this population and bred in Norway, Sweden and Finland,or rather originated from the Central European population, especially since most neck collar observations were of birds ringed in the Czech Republic. Stable hydrogen isotope (δ 2 H) analyses of feathers from 147 individuals hunted or trapped during winter in Camargue provide some insight into this question and suggest north-central Europe as a more likely area of origin. This indicates that greylags wintering along the Mediterranean coast maybe largely separate from the birds of the NW/SW European population breeding in Fennoscandia, although some individuals may also come from the Polish or German regions of the NW/SW flyway, since the combined ringing and stable isotope analyses suggest these birds are mostly breeding and moulting in an isotopic area consistent with the Czech Republic, Poland and northern Germany. Earlier studies show birds wintering in other French regions rather originate from Sweden and Norway. These results should be considered for the management plan currently being developed for greylag goose in Europe. More generally, they question whether birds from two distinct populations /flyways should be applied similar or potentially different management plans within a given country

Achieving very long lifetimes in optical lattices with pulsed cooling

We have realized a one dimensional optical lattice for individual atoms with a lifetime >300 s, which is 5 times longer than previously reported. In order to achieve this long lifetime, it is necessary to laser cool the at-oms briefly every 20 s to overcome heating due to technical fluctuations in the trapping potential. Without cooling, we observe negligible atom loss within the first 20 s followed by an exponential decay with a 62 s time constant. We obtain quantitative agreement with the measured fluctuations of the trapping potential and the corresponding theoretical heating rates.Comment: 4 pages, 5 figure

Brexit, private equity and management

We analyse the expected impact of Brexit on private equity and its implications for management research. Specifically, we explore the implications for PE funds and funding, and at the portfolio firm level with respect to employment and performance

Deep learning for necrosis detection using canine perivascular wall tumour whole slide images

Necrosis seen in histopathology Whole Slide Images is a major criterion that contributes towards scoring tumour grade which then determines treatment options. However conventional manual assessment suffers from inter-operator reproducibility impacting grading precision. To address this, automatic necrosis detection using AI may be used to assess necrosis for final scoring that contributes towards the final clinical grade. Using deep learning AI, we describe a novel approach for automating necrosis detection in Whole Slide Images, tested on a canine Soft Tissue Sarcoma (cSTS) data set consisting of canine Perivascular Wall Tumours (cPWTs). A patch-based deep learning approach was developed where different variations of training a DenseNet-161 Convolutional Neural Network architecture were investigated as well as a stacking ensemble. An optimised DenseNet-161 with post-processing produced a hold-out test F1-score of 0.708 demonstrating state-of-the-art performance. This represents a novel first-time automated necrosis detection method in the cSTS domain as well specifically in detecting necrosis in cPWTs demonstrating a significant step forward in reproducible and reliable necrosis assessment for improving the precision of tumour grading