Compact, efficient ultra-wide tunable laser with reduced thermal crosstalk.

Future optical communication systems will exploit increasingly wide optical wavelength bands to continue scaling capacity per installed fiber. Currently, optical components such as tunable lasers and modulators are designed to operate in a single wavelength band only and multiple designs are therefore needed for a single system. Improved tunable lasers operating seamlessly over these wider bands would both simplify system deployment and management.

Low-voltage surface-normal electroabsorption modulators.

Surface-normal electroabsorption modulators (SNEAMs) are appealing for short-reach communication systems because of their outstanding properties, such as ultrawide bandwidth and polarization-insensitive response; however, due to their small active volumes, large voltage swings are typically required to obtain the best performance. Here we propose and demonstrate a novel, to the best of our knowledge, design that dramatically reduces the voltage needed by SNEAMs and significantly increases their extinction ratio. By shrinking the multiple quantum well stack of SNEAMs to the minimum and by optimizing their reflectivity with dielectric coatings of suitable refractive index and thickness, we obtain modulators that require drive voltages of only 1-2.

PAM-4 transmission up to 160 Gb/s with surface-normal electro-absorption modulators.

We report multi-level modulation in polarization-independent surface-normal electro-absorption modulators (SNEAMs). Four-level pulse amplitude modulation (PAM-4) at a line rate of 44 Gb/s is demonstrated on a fully packaged SNEAM with a 30 µm active area diameter and a 14 GHz electro-optic bandwidth. High-capacity PAM-4 transmission at 112 and 160 Gb/s is demonstrated on an unpackaged SNEAM chip, with a 15 µm active area diameter and ultrawide electro-optic bandwidth (≫65).

Power insensitive surface-normal electroabsorption modulators.

Surface-normal electroabsorption modulators (SNEAMs) have unique electro-optic modulation properties; however, their behavior and performance at high light intensity is affected by thermal nonlinearities that take place in the modulator active volume. Here we show a novel, to the best of our knowledge, approach to make SNEAMs insensitive to optical power without the use of power-hungry heaters or feedback control systems. By passively compensating for the thermo-optic dependence of the SNEAM resonant cavity, we obtain an eight-fold reduction in the wavelength shift of the SNEAM response at 4 dBm of input power.

Open Source Brain: A Collaborative Resource for Visualizing, Analyzing, Simulating, and Developing Standardized Models of Neurons and Circuits.

Computational models are powerful tools for exploring the properties of complex biological systems. In neuroscience, data-driven models of neural circuits that span multiple scales are increasingly being used to understand brain function in health and disease. But their adoption and reuse has been limited by the specialist knowledge required to evaluate and use them.

Geppetto: a reusable modular open platform for exploring neuroscience data and models.

Geppetto is an open-source platform that provides generic middleware infrastructure for building both online and desktop tools for visualizing neuroscience models and data and managing simulations. Geppetto underpins a number of neuroscience applications, including Open Source Brain (OSB), Virtual Fly Brain (VFB), NEURON-UI and NetPyNE-UI. OSB is used by researchers to create and visualize computational neuroscience models described in NeuroML and simulate them through the browser.

Screening of benzodiazepines in thirty European rivers.

Pharmaceuticals as environmental contaminants have received a lot of interest over the past decade but, for several pharmaceuticals, relatively little is known about their occurrence in European surface waters. Benzodiazepines, a class of pharmaceuticals with anxiolytic properties, have received interest due to their behavioral modifying effect on exposed biota. In this study, our results show the presence of one or more benzodiazepine(s) in 86% of the analyzed surface water samples (n = 138) from 30 rivers, representing seven larger European catchments.

A first European scale multimedia fate modelling of BDE-209 from 1970 to 2020.

The European Variant Berkeley Trent (EVn-BETR) multimedia fugacity model is used to test the validity of previously derived emission estimates and predict environmental concentrations of the main decabromodiphenyl ether congener, BDE-209. The results are presented here and compared with measured environmental data from the literature. Future multimedia concentration trends are predicted using three emission scenarios (Low, Realistic and High) in the dynamic unsteady state mode covering the period 1970-2020.

Comparing measured and modelled PFOS concentrations in a UK freshwater catchment and estimating emission rates.

The lifecycle, sources and fate of perfluorooctane sulfonate (PFOS) continue to generate scientific and political interest, particularly since PFOS was listed by the Stockholm Convention and largely restricted in Europe. It continues to be detected in aquatic environments, with only limited studies into the on-going sources. This paper explores PFOS emissions discharged by the general population into a small catchment comprising two rivers in the UK.

Free-space coherent optical communication with orbital angular, momentum multiplexing/demultiplexing using a hybrid 3D photonic integrated circuit.

We demonstrate free-space space-division-multiplexing (SDM) with 15 orbital angular momentum (OAM) states using a three-dimensional (3D) photonic integrated circuit (PIC). The hybrid device consists of a silica planar lightwave circuit (PLC) coupled to a 3D waveguide circuit to multiplex/demultiplex OAM states. The low excess loss hybrid device is used in individual and two simultaneous OAM states multiplexing and demultiplexing link experiments with a 20 Gb/s, 1.

Estimating European historical production, consumption and atmospheric emissions of decabromodiphenyl ether.

A European scale production, consumption and environmental emissions inventory is produced for decabromodiphenyl ether (DecaBDE) for the period 1970-2020. A dynamic substance flow analysis model of DecaBDE is developed and emission of the main congener, BDE-209, to environmental compartments is estimated. From 1970 to 2010, it is estimated that a total of 185,000-250,000 tonnes of DecaBDE was consumed in Europe.

Linear phase-and-frequency-modulated photonic links using optical discriminators.

We report our experimental results for linear analog optical links that use phase or frequency modulation and optical discrimination. The discriminators are based on two architectures: a cascaded MZI FIR lattice filter and a ring assisted MZI (RAMZI) IIR filter. For both types of discriminators, we demonstrate > 6 dB improvement in the link's third-order output intercept point (OIP3) over a MZM link.

Atmospheric polybrominated diphenyl ethers (PBDEs) in the United Kingdom.

The occurrence of PBDEs has been studied in the atmosphere of four sites in the United Kingdom over a period of ten years. The concentrations have exhibited a sharp decrease after 2001-2003. This is evident in the urban sites of Manchester and London and at the semi-rural site of Hazelrigg.

Does psychoeducation help prevent post traumatic psychological distress?

Psychoeducation is increasingly used following trauma. The term covers the provision of information about the nature of stress, posttraumatic and other symptoms, and what to do about them. The provision of psychoeducation can also occur before possible exposure to stressful situations or, alternatively, after exposure.

The operational mental health consequences of deployment to Iraq for UK Forces.

UK Forces are currently engaged in high tempo, high intensity operations in both Iraq and Afghanistan. Concern has been raised about the impact of current operations upon the mental health of Service personnel. Using data gathered from deployed Field Mental Health Teams, a random sample of UK based non-deployed Community Mental Health Teams and services dedicated to mobilising, de-mobilising and to de-mobilised Reserve Forces, this paper explores the current mental health burden for UK Forces.

A hybrid electroabsorption modulator device for generation of high spectral-efficiency optical modulation formats.

We report a novel hybrid integrated optic device consisting of AlGaInAs/InP electroabsorption modulators and a four-arm silica-on-silicon planar lightwave circuit optical interferometer. The device is designed for generation of high spectral efficiency optical modulation formats. We demonstrate generation of 21.

Risk factors for post-traumatic stress disorder among UK Armed Forces personnel.

Background: There is considerable interest in understanding further the factors that increase the risk of post-traumatic stress disorder (PTSD) for military personnel. This study aimed to investigate the relative contribution of demographic variables; childhood adversity; the nature of exposure to traumatic events during deployment; appraisal of these experiences; and home-coming experiences in relation to the prevalence of PTSD 'caseness' as measured by a score of 50 on the PTSD Checklist (PCL) in UK Armed Forces personnel who have been deployed in Iraq since 2003.

Method: Data were drawn from the first stage of a retrospective cohort study comparing UK military personnel who were deployed to the 2003 Iraq War with personnel serving in the UK Armed Forces on 31 March 2003 but who were not deployed to the initial phase of war fighting.

Patterns of drinking in the UK Armed Forces.

Aims: To examine patterns of drinking in the UK Armed Forces, how they vary according to gender and other demographics, and to make comparisons with the general population.

Design: Large cross-sectional postal questionnaire study (response rate 60%).

Setting: United Kingdom.

Mental health consequences of overstretch in the UK armed forces: first phase of a cohort study.

Objective: To assess the relation between frequency and duration of deployment of UK armed forces personnel on mental health.

Design: First phase of a cohort study.

Setting: UK armed forces personnel.

The health of UK military personnel who deployed to the 2003 Iraq war: a cohort study.

Background: Concerns have been raised about the mental and physical health of UK military personnel who deployed to the 2003 war in Iraq and subsequent tours of duty in the country.

Methods: We compared health outcomes in a random sample of UK armed forces personnel who were deployed to the 2003 Iraq war with those in personnel who were not deployed. Participants completed a questionnaire covering the nature of the deployment and health outcomes, which included symptoms of post-traumatic stress disorder, common mental disorders, general wellbeing, alcohol consumption, physical symptoms, and fatigue.

Photosynthetic pathway, chilling tolerance and cell sap osmotic potential values of grasses along an altitudinal gradient in Papua New Guinea.

A total of 22 grass species were examined from 5 sites spanning the altitudinal range 1550-4350 m.a.s.

Failure of mebendazole to cure trichomonal vaginitis resistant to metronidazole: case reports.

After a recent report showing the in vitro susceptibility to mebendazole of a strain of Trichomonas vaginalis that was resistant to metronidazole, we present two cases of metronidazole resistant infection, both of which failed to respond to oral mebendazole.

Temperature dependent factors influencing nutrient uptake: an analysis of responses at different levels of organization.

Ion fluxes show a characteristically biochemical dependence on temperature when observed at the membrane level and over short periods after a perturbation of temperature. The primary active transport systems are enzymic and are dependent both on substrate supply and on changes in protein conformation. The hydrophobic parts of the proteins are surrounded by lipid molecules whose physical state may crucially affect conformation changes.

Short-term studies on the use of amino acids as an osmotic agent in continuous ambulatory peritoneal dialysis.

1. A 1% amino acid dialysis solution with a high concentration of the branched-chain amino acids has been compared with 1.36% glucose in short-term studies.