Seagrass science is growing: a report on the 12th International Seagrass Biology Workshop

This conference report describes the programme of the 12th International Seagrass Biology Workshop, its highlights, areas of growth for the workshop, and potential future directions for the workshop series. The report is written with an eye toward where it fits within the field of seagrass research

RNA-seq reveals post-transcriptional regulation of Drosophila insulin-like peptide dilp8 and the neuropeptide-like precursor Nplp2 by the exoribonuclease Pacman/XRN1

Ribonucleases are critically important in many cellular and developmental processes and defects in their expression are associated with human disease. Pacman/XRN1 is a highly conserved cytoplasmic exoribonuclease which degrades RNAs in a 5' - 3' direction. In Drosophila, null mutations in pacman result in small imaginal discs, a delay in onset of pupariation and lethality during the early pupal stage. In this paper, we have used RNA-seq in a genome-wide search for mRNAs misregulated in pacman null wing imaginal discs. Only 4.2% of genes are misregulated ±>2-fold in pacman null mutants compared to controls, in line with previous work showing that Pacman has specificity for particular mRNAs. Further analysis of the most upregulated mRNAs showed that Pacman post-transcriptionally regulates the expression of the secreted insulin-like peptide Dilp8. Dilp8 is related to human IGF-1, and has been shown to co-ordinate tissue growth with developmental timing in Drosophila. The increased expression of Dilp8 is consistent with the developmental delay seen in pacman null mutants. Our analysis, together with our previous results, show that the normal role of this exoribonuclease in imaginal discs is to suppress the expression of transcripts that are crucial in apoptosis and growth control during normal development

Effect of hyperon bulk viscosity on neutron-star r-modes

Neutron stars are expected to contain a significant number of hyperons in addition to protons and neutrons in the highest density portions of their cores. Following the work of Jones, we calculate the coefficient of bulk viscosity due to nonleptonic weak interactions involving hyperons in neutron-star cores, including new relativistic and superfluid effects. We evaluate the influence of this new bulk viscosity on the gravitational radiation driven instability in the r-modes. We find that the instability is completely suppressed in stars with cores cooler than a few times 10^9 K, but that stars rotating more rapidly than 10-30% of maximum are unstable for temperatures around 10^10 K. Since neutron-star cores are expected to cool to a few times 10^9 K within seconds (much shorter than the r-mode instability growth time) due to direct Urca processes, we conclude that the gravitational radiation instability will be suppressed in young neutron stars before it can significantly change the angular momentum of the star.Comment: final PRD version, minor typos etc correcte

The influence of alcohol content variation in UK packaged beers on the uncertainty of calculations using the Widmark equation

It is common for forensic practitioners to calculate an individual's likely blood alcohol concentration following the consumption of alcoholic beverage(s) for legal purposes, such as in driving under the influence (DUI) cases. It is important in these cases to be able to give the uncertainty of measurement on any calculated result, for this reason uncertainty data for the variables used for any calculation are required. In order to determine the uncertainty associated with the alcohol concentration of beer in the UK the alcohol concentration (%v/v) of 218 packaged beers (112 with an alcohol concentration of ≤5.5%v/v and 106 with an alcohol concentration of >5.5%v/v) were tested using an industry standard near infra-red (NIR) analyser. The range of labelled beer alcohol by volume (ABV's) tested was 3.4%v/v – 14%v/v. The beers were obtained from a range of outlets throughout the UK over a period of 12 months. The root mean square error (RMSE) was found to be ±0.43%v/v (beers with declared %ABV of ≤5.5%v/v) and ±0.53%v/v (beers with declared %ABV of >5.5%v/v) the RMSE for all beers was ±0.48%v/v. The standard deviation from the declared %ABV is larger than those previously utilised for uncertainty calculations and illustrates the importance of appropriate experimental data for use in the determination of uncertainty in forensic calculations

Schemes for Parallel Quantum Computation Without Local Control of Qubits

Typical quantum computing schemes require transformations (gates) to be targeted at specific elements (qubits). In many physical systems, direct targeting is difficult to achieve; an alternative is to encode local gates into globally applied transformations. Here we demonstrate the minimum physical requirements for such an approach: a one-dimensional array composed of two alternating 'types' of two-state system. Each system need be sensitive only to the net state of its nearest neighbors, i.e. the number in state 1 minus the number in state 2. Additionally, we show that all such arrays can perform quite general parallel operations. A broad range of physical systems and interactions are suitable: we highlight two potential implementations.Comment: 12 pages + 3 figures. Several small corrections mad

A Model of Meter Perception in Music

A fundamental problem in music cognition is the question of how the listener extracts the music's temporal organization. We describe a model, implemented as a computer simulation, that constructs a hierarchical representation of metric structure that conforms to the requirements of Lerdahl & Jackendoff's(1983) generative theory. The model integrates bottom-up processing of score data with top-down processes that generate predictions of temporal structure,and with rules of organization that correspond to musical intuition. Several examples of the program's output are used to illustrate these processes

Global Optical Control of a Quantum Spin Chain

Quantum processors which combine the long decoherence times of spin qubits together with fast optical manipulation of excitons have recently been the subject of several proposals. I show here that arbitrary single- and entangling two-qubit gates can be performed in a chain of perpetually coupled spin qubits solely by using laser pulses to excite higher lying states. It is also demonstrated that universal quantum computing is possible even if these pulses are applied {\it globally} to a chain; by employing a repeating pattern of four distinct qubit units the need for individual qubit addressing is removed. Some current experimental qubit systems would lend themselves to implementing this idea.Comment: 5 pages, 3 figure

Rapid online buffer exchange for screening of proteins, protein complexes and cell lysates by native mass spectrometry

It is important to assess the identity and purity of proteins and protein complexes during and after protein purification to ensure that samples are of sufficient quality for further biochemical and structural characterization, as well as for use in consumer products, chemical processes and therapeutics. Native mass spectrometry (nMS) has become an important tool in protein analysis due to its ability to retain non-covalent interactions during measurements, making it possible to obtain protein structural information with high sensitivity and at high speed. Interferences from the presence of non-volatiles are typically alleviated by offline buffer exchange, which is time-consuming and difficult to automate. We provide a protocol for rapid online buffer exchange (OBE) nMS to directly screen structural features of pre-purified proteins, protein complexes or clarified cell lysates. In the liquid chromatography coupled to mass spectrometry (LC-MS) approach described in this protocol, samples in MS-incompatible conditions are injected onto a short size-exclusion chromatography column. Proteins and protein complexes are separated from small molecule non-volatile buffer components using an aqueous, non-denaturing mobile phase. Eluted proteins and protein complexes are detected by the mass spectrometer after electrospray ionization. Mass spectra can inform regarding protein sample purity and oligomerization, and additional tandem mass spectra can help to further obtain information on protein complex subunits. Information obtained by OBE nMS can be used for fast (<5 min) quality control and can further guide protein expression and purification optimization