Optical alignment and spinning of laser-trapped microscopic particles

Light-induced rotation of absorbing microscopic particles by transfer of angular momentum from light to the material raises the possibility of optically driven micromachines. The phenomenon has been observed using elliptically polarized laser beams or beams with helical phase structure. But it is difficult to develop high power in such experiments because of overheating and unwanted axial forces, limiting the achievable rotation rates to a few hertz. This problem can in principle be overcome by using transparent particles, transferring angular momentum by a mechanism first observed by Beth in 1936, when he reported a tiny torque developed in a quartz waveplate due to the change in polarization of transmitted light. Here we show that an optical torque can be induced on microscopic birefringent particles of calcite held by optical tweezers. Depending on the polarization of the incident beam, the particles either become aligned with the plane of polarization (and thus can be rotated through specified angles) or spin with constant rotation frequency. Because these microscopic particles are transparent, they can be held in three-dimensional optical traps at very high power without heating. We have observed rotation rates in excess of 350 Hz.Comment: 4 pages, 4 figure

Historical processes and contemporary anthropogenic activities influence genetic population dynamics of Nassau grouper (Epinephelus striatus) within The Bahamas

This is the final version of the article. Available from Frontiers Media via the DOI in this record.Severe declines of endangered Nassau grouper (Epinephelus striatus) across The Bahamas and Caribbean have spurred efforts to improve their fisheries management and population conservation. The Bahamas is reported to hold the majority of fish spawning aggregations for Nassau grouper, however, the status and genetic population structure of fish within the country is largely unknown, presenting a major knowledge gap for their sustainable management. Between August 2014-February 2017, 464 individual Nassau grouper sampled from The Bahamas were genotyped using 15 polymorphic microsatellite loci to establish measures of population structure, genetic diversity and effective population size (N e ). Nassau grouper were characterized by mostly high levels of genetic diversity, but we found no evidence for geographic population structure. Microsatellite analyses revealed weak, but significant genetic differentiation of Nassau grouper throughout the Bahamian archipelago (Global FST 0.00236, p = 0.0001). Temporal analyses of changes in N e over the last 1,000 generations provide evidence in support of a pronounced historic decline in Bahamian Nassau grouper that appears to pre-date anthropogenic fishing activities. M-ratio results corroborate significant reductions in N e throughout The Bahamas, with evidence for population bottlenecks in three islands and an active fish spawning aggregation along with apparent signs of inbreeding at two islands. Current estimates of N e for Nassau grouper are considerably lower compared with historic levels. These findings represent important new contributions to our understanding of the evolutionary history, demographics and genetic connectivity of this endangered species, which are of critical importance for advancing their sustainable management.Molecular research was financially supported by the University of Exeter and research cruises were funded by the John G. Shedd Aquarium. Partial funding for KS was provided by the Shirley Oakes Butler Charitable Trust, Rotary Club of East Nassau and a private donation by I. de la Rocha

Mindfulness-based stress reduction in Parkinson’s disease: a systematic review

Background: Mindfulness based stress reduction (MBSR) is increasingly being used to improve outcomes such as stress and depression in a range of long-term conditions (LTCs). While systematic reviews on MBSR have taken place for a number of conditions there remains limited information on its impact on individuals with Parkinson’s disease (PD). Methods: Medline, Central, Embase, Amed, CINAHAL were searched in March 2016. These databases were searched using a combination of MeSH subject headings where available and keywords in the title and abstracts. We also searched the reference lists of related reviews. Study quality was assessed based on questions from the Cochrane Collaboration risk of bias tool. Results: Two interventions and three papers with a total of 66 participants were included. The interventions were undertaken in Belgium (n = 27) and the USA (n = 39). One study reported significantly increased grey matter density (GMD) in the brains of the MBSR group compared to the usual care group. Significant improvements were reported in one study for a number of outcomes including PD outcomes, depression, mindfulness, and quality of life indicators. Only one intervention was of reasonable quality and both interventions failed to control for potential confounders in the analysis. Adverse events and reasons for drop-outs were not reported. There was also no reporting on the costs/benefits of the intervention or how they affected health service utilisation. Conclusion: This systematic review found limited and inconclusive evidence of the effectiveness of MBSR for PD patients. Both of the included interventions claimed positive effects for PD patients but significant outcomes were often contradicted by other results. Further trials with larger sample sizes, control groups and longer follow-ups are needed before the evidence for MBSR in PD can be conclusively judged

Scepticism and perceived self-efficacy influence fishers’ low risk perceptions of climate change

This is the final version. Available from Elsevier via the DOI in this record. Anonymised quantitative data that support these findings are available from the author upon reasonable request, but are not held on an openly public database due to the confidentiality of the data.Climate change is impacting fisheries globally, posing both risks and opportunities to those dependent on marine resources. Understanding how fishers perceive climate change, and what factors shape these perceptions, can provide insights into behavioural intentions and support required for climate change focused strategies and management. This study interviewed demersal fishers from a south-west UK fishing port to explore: 1) the future risks fishers identified that may affect their business and wider industry; 2) fishers’ beliefs and risk perceptions relating to climate change; and 3) the factors influencing these perceptions. Fishers identified a number of environmental, socio-economic and fisheries governance risks but climate change was rarely mentioned. While fishers overall had low risk perceptions of climate change, these perceptions were heterogeneous across the sample. Climate change scepticism and a high perceived self-efficacy to adapt to climate change were associated with lower risk perceptions. These findings provide new insights into how fishers perceive climate change and, importantly, greater understanding of the possible drivers of such perceptions. Findings suggest that undertaking climate-awareness raising initiatives in isolation to support adaptation strategies could be limited in success. Instead, wider focus should be applied to removing barriers to adaptation, managing wider risks and incorporating fishers into decision making to effectively support and motivate fishers’ adaptation.Natural Environment Research Council (NERC

Pregnancy postponement and childlessness leads to chronic hypervascularity of the breasts and cancer risk

Epidemiologists have established that women with small families, and particularly nulliparae, are prone to develop breast cancer later in life. We report that physiological mammary hypervascularity may be an intermediate reason against the background that breast-core vascularity is normal in pregnancy but pathological in the vascularisation of cancer. We examined breast ‘core’ vascularity in nulliparae during their potential reproductive life and in parous women after their last birth but before their menopause. Fifty clinically normal pre-menopausal non-pregnant women (100 breasts) were studied daily for one ‘luteal positive’ menstrual cycle. Their parity history varied from zero to five babies. Under controlled domestic conditions each wore a special electronic thermometric bra to automatically record breast ‘core’ temperature changes as a measure of mammary tissue blood flow. In the nulliparae there was a rise of breast vascularity throughout reproductive life. In the parous women, a year or so after each birth, breast vascularity was reset at a lower level than before the pregnancy; thereafter, as in nulliparae, there was progressive increase in mammary vascularity until the menopause

Mexico City and the biogeochemistry of global urbanization

Mexico City is far advanced in its urban evolution, and cities in currently developing nations may soon follow a similar course. This paper investigates the strengths and weaknesses of infrastructures for the emerging megacities. The major driving force for infrastructure change in Mexico City is concern over air quality. Air chemistry data from recent field campaigns have been used to calculate fluxes in the atmosphere of the Valley of Mexico, for compounds that are important to biogeochemistry including methane (CH4), carbon monoxide (CO), nonmethane hydrocarbons (NMHCs), ammonia (NH3), sulfur dioxide (SO2), nitrogen oxides (NOx and NOy), soot, and dust. Leakage of liquified petroleum gas approached 10% during sampling periods, and automotive pollutant sources in Mexico City were found to match those in developed cities, despite a lower vehicle-to-person ratio of 0.1. Ammonia is released primarily from residential areas, at levels sufficient to titrate pollutant acids into particles across the entire basin. Enhancements of reduced nitrogen and hydrocarbons in the vapor phase skew the distribution of NOy species towards lower average deposition velocities. Partly as a result, downwind nutrient deposition occurs on a similar scale as nitrogen fixation across Central America, and augments marine nitrate upwelling. Dust suspension from unpaved roads and from the bed of Lake Texcoco was found to be comparable to that occurring on the periphery of the Sahara, Arabian, and Gobi deserts. In addition, sodium chloride (NaCl) in the dust may support heterogeneous chlorine oxide (ClOx) chemistry. The insights from our Mexico City analysis have been tentatively applied to the upcoming urbanization of Asia

Considering the Case for Biodiversity Cycles: Reexamining the Evidence for Periodicity in the Fossil Record

Medvedev and Melott (2007) have suggested that periodicity in fossil biodiversity may be induced by cosmic rays which vary as the Solar System oscillates normal to the galactic disk. We re-examine the evidence for a 62 million year (Myr) periodicity in biodiversity throughout the Phanerozoic history of animal life reported by Rohde & Mueller (2005), as well as related questions of periodicity in origination and extinction. We find that the signal is robust against variations in methods of analysis, and is based on fluctuations in the Paleozoic and a substantial part of the Mesozoic. Examination of origination and extinction is somewhat ambiguous, with results depending upon procedure. Origination and extinction intensity as defined by RM may be affected by an artifact at 27 Myr in the duration of stratigraphic intervals. Nevertheless, when a procedure free of this artifact is implemented, the 27 Myr periodicity appears in origination, suggesting that the artifact may ultimately be based on a signal in the data. A 62 Myr feature appears in extinction, when this same procedure is used. We conclude that evidence for a periodicity at 62 Myr is robust, and evidence for periodicity at approximately 27 Myr is also present, albeit more ambiguous.Comment: Minor modifications to reflect final published versio

Patient access to complex chronic disease records on the internet

Background: Access to medical records on the Internet has been reported to be acceptable and popular with patients, although most published evaluations have been of primary care or office-based practice. We tested the feasibility and acceptability of making unscreened results and data from a complex chronic disease pathway (renal medicine) available to patients over the Internet in a project involving more than half of renal units in the UK. Methods: Content and presentation of the Renal PatientView (RPV) system was developed with patient groups. It was designed to receive information from multiple local information systems and to require minimal extra work in units. After piloting in 4 centres in 2005 it was made available more widely. Opinions were sought from both patients who enrolled and from those who did not in a paper survey, and from staff in an electronic survey. Anonymous data on enrolments and usage were extracted from the webserver. Results: By mid 2011 over 17,000 patients from 47 of the 75 renal units in the UK had registered. Users had a wide age range (<10 to >90 yrs) but were younger and had more years of education than non-users. They were enthusiastic about the concept, found it easy to use, and 80% felt it gave them a better understanding of their disease. The most common reason for not enrolling was being unaware of the system. A minority of patients had security concerns, and these were reduced after enrolling. Staff responses were also strongly positive. They reported that it aided patient concordance and disease management, and increased the quality of consultations with a neutral effect on consultation length. Neither patient nor staff responses suggested that RPV led to an overall increase in patient anxiety or to an increased burden on renal units beyond the time required to enrol each patient. Conclusions: Patient Internet access to secondary care records concerning a complex chronic disease is feasible and popular, providing an increased sense of empowerment and understanding, with no serious identified negative consequences. Security concerns were present but rarely prevented participation. These are powerful reasons to make this type of access more widely available

Mathematizing Darwin

Ernst Mayr called the first part of the evolutionary synthesis the ‘Fisherian synthesis’ on account of the dominant role played by R.A. Fisher in forging a mathematical theory of natural selection together with J.B.S. Haldane and Sewall Wright in the decade 1922–1932. It is here argued that Fisher’s contribution relied on a close reading of Darwin’s work to a much greater extent than did the contributions of Haldane and Wright, that it was synthetic in contrast to their analytic approach and that it was greatly influenced by his friendship with the Darwin family, particularly with Charles’s son Leonard

How a bird is an island

Replicate adaptive radiations occur when lineages repeatedly radiate and fill new but similar niches and converge phenotypically. While this is commonly seen in traditional island systems, it may also be present in host-parasite relationships, where hosts serve as islands. In a recent article in BMC Biology, Johnson and colleagues have produced the most extensive phylogeny of the avian lice (Ischnocera) to date, and find evidence for this pattern. This study opens the door to exploring adaptive radiations from a novel host-parasite perspective