The first demonstration of laser action in ruby was made in 1960 by T. H. Maiman of Hughes Research Laboratories, USA. Many laboratories worldwide began the search for lasers using different materials, operating at different wavelengths. In the UK, academia, industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications. This historical review looks at the contribution the UK has made to the advancement of the technology, the development of systems and components and their exploitation over the last 60 years.

Three-dimensional (3D) printing has expanded beyond the mere patterned deposition of melted solids, moving into areas requiring spatially structured soft matter—typically materials composed of polymers, colloids, surfactants, or living cells. The tunable and dynamically variable rheological properties of soft matter enable the high-resolution manufacture of soft structures. These rheological properties are leveraged in 3D printing techniques that employ sacrificial inks and sacrificial support materials, which go through reversible solid–fluid transitions under modest forces or other small perturbations. Thus, a sacrificial material can be used to shape a second material into a complex 3D structure, and then discarded. Here, we review the sacrificial materials and related methods used to print soft structures. We analyze data from the literature to establish manufacturing principles of soft matter printing, and we explore printing performance within the context of instabilities controlled by the rheology of soft matter materials.

Giant ragweed has been increasing as a major weed of row crops in the last30 yr, but quantitative data regarding its pattern and mechanisms of spreadin crop fields are lacking. To address this gap, we conducted a Web-basedsurvey of certified crop advisors in the U.S. Corn Belt and Ontario, Canada.Participants were asked questions regarding giant ragweed and cropproduction practices for the county of their choice. Responses were mappedand correlation analyses were conducted among the responses to determinefactors associated with giant ragweed populations. Respondents rated giantragweed as the most or one of the most difficult weeds to manage in 45% of421 U.S. counties responding, and 57% of responding counties reported giantragweed populations with herbicide resistance to acetolactate synthaseinhibitors, glyphosate, or both herbicides. Results suggest that giantragweed is increasing in crop fields outward from the east-central U.S. CornBelt in most directions. Crop production practices associated with giantragweed populations included minimum tillage, continuous soybean, andmultiple-application herbicide programs; ecological factors included giantragweed presence in noncrop edge habitats, early and prolonged emergence,and presence of the seed-burying common earthworm in crop fields. Managinggiant ragweed in noncrop areas could reduce giant ragweed migration fromnoncrop habitats into crop fields and slow its spread. Where giant ragweedis already established in crop fields, including a more diverse combinationof crop species, tillage practices, and herbicide sites of action will becritical to reduce populations, disrupt emergence patterns, and selectagainst herbicide-resistant giant ragweed genotypes. Incorporation of acereal grain into the crop rotation may help suppress early giant ragweedemergence and provide chemical or mechanical control options forlate-emerging giant ragweed.

We have mapped cold atomic gas in 21cm line H i self-absorption (HISA) at arcminute resolution over more than 90% of the Milky Way's disk. To probe the formation of H2 clouds, we have compared our HISA distribution with CO J = 1-0 line emission. Few HISA features in the outer Galaxy have CO at the same position and velocity, while most inner-Galaxy HISA has overlapping CO. But many apparent inner-Galaxy HISA-CO associations can be explained as chance superpositions, so most inner-Galaxy HISA may also be CO-free. Since standard equilibrium cloud models cannot explain the very cold H i in many HISA features without molecules being present, these clouds may instead have significant CO-dark H2.

Recent studies suggest that sand can serve as a vehicle for exposure of humans to pathogens at beach sites, resulting in increased health risks. Sampling for microorganisms in sand should therefore be considered for inclusion in regulatory programmes aimed at protecting recreational beach users from infectious disease. Here, we review the literature on pathogen levels in beach sand, and their potential for affecting human health. In an effort to provide specific recommendations for sand sampling programmes, we outline published guidelines for beach monitoring programmes, which are currently focused exclusively on measuring microbial levels in water. We also provide background on spatial distribution and temporal characteristics of microbes in sand, as these factors influence sampling programmes. First steps toward establishing a sand sampling programme include identifying appropriate beach sites and use of initial sanitary assessments to refine site selection. A tiered approach is recommended for monitoring. This approach would include the analysis of samples from many sites for faecal indicator organisms and other conventional analytes, while testing for specific pathogens and unconventional indicators is reserved for high-risk sites. Given the diversity of microbes found in sand, studies are urgently needed to identify the most significant aetiological agent of disease and to relate microbial measurements in sand to human health risk.

Plutonium and Pu-Ga alloys have been observed to have anomalous hydrogen solubility behavior, including a significant concentration dependence of hydrogen diffusivity in the dilute regime, a sharp drop off in the hydrogen solubility constant in the dilute regime, and a near complete absence of change in the Sieverts’ constant as the alloys are heated across phase transformation boundaries. We are investigating the possibility that a vacancy mechanism is responsible for this behavior. X-ray diffraction measurements show a 0.14% lattice contraction in Pu-2 at. % Ga alloys when they are charged with ~2 at. % hydrogen. The lattice re-expands when the hydrogen is removed. Density functional calculations show that increasing the number of hydrogen atoms associated with a vacant lattice site in Pu lowers the energy of the hydrogen-vacancy complex. These observations support the idea that vacancies are stabilized by hydrogen in the Pu lattice well beyond their thermal equilibrium concentration and could be responsible for the anomalous hydrogen response of Pu.

The Tarantula Survey is an ESO Large Programme which has obtained multi-epoch spectroscopy of over 1,000 massive stars in the 30 Doradus region of the Large Magellanic Cloud. The assembled consortium will exploit these data to address a range of fundamental questions in both stellar and cluster evolution.

Twenty-nine patients (16 males, 13 females) with Joubert syndrome were identified from ophthalmology, neurology, and genetic databases covering a 15-year period at Great Ormond Street Hospital, London. Criteria for diagnosis included absent or markedly hypoplastic cerebellar vermis, abnormal eye movements, and developmental delay. Five patients had died. Scans and notes were available for 22 patients, and 18 cases were clinically reviewed. The median age was 10 years 10 months (range 3mo to 19y) and the median follow-up was 8 years 5 months (range 3mo to 19y, with one new patient seen at 3mo of age). Cerebellar vermis hypoplasia/aplasia with ‘molar tooth sign’ in the axial plane was present in 22 of 22 patients, coloboma in 6 of 22, and polydactyly in 6 of 22. In the 18 clinically reviewed, apnoea occurred in 13 patients. Five had renal problems with cysts and 4 of 5 had abnormal electroretinograms (ERGs). Visual electrophysiology was abnormal in 14 of 18 patients, and in 6 there was evidence of deterioration in the ERG. Blood investigations of organic acids, phytanic acid, very-long-chain fatty acid, and transferrin were normal in 12 patients tested. Developmental assessment showed that 6 of 15 patients aged more than 5 years were at mainstream school, and 12 of 18 had started walking between 22 months and 10 years. Speech difficulties and behavioural problems were prominent.