1,743 research outputs found

    Optical binding between knotted and chiral nanoparticles

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    Optical binding between nanowires

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    Transcutaneous electrical nerve stimulation for cancer pain in adults.

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    Background Cancer-related pain is complex and multi-dimensional but the mainstay of cancer pain management has predominately used a biomedical approach. There is a need for non-pharmacological and innovative approaches. Transcutaneous Electric Nerve Stimulation (TENS) may have a role for a significant number of patients but the effectiveness of TENS is currently unknown. Objectives The aim of this systematic review was to determine the effectiveness of TENS for cancer-related pain in adults. Search strategy We searched The Cochrane Library, MEDLINE, EMBASE, CINAHL, PsychINFO, AMED and PEDRO databases (11/04/08). Selection criteria Only randomised controlled trials (RCTS) investigating the use of TENS for the management of cancer-related pain in adults were included. Data collection and analysis The search strategy identified 37 possible published studies which were divided between two pairs of review authors that decided on study selection. A study eligibility form was used to screen each abstract and where study eligibility could not be determined from the abstract, the full paper was obtained and assessed by one pair of review authors. A standardised data extraction sheet was used to collect information on the studies and the quality of the studies was assessed independently by two review authors using the validated five-point Oxford Quality Scale. Final scores were discussed and agreed between all four review authors. The small sample sizes and differences in patient study populations of the two included studies prevented meta-analysis. Main results Only two RCTs met the eligibility criteria (64 participants). These studies were heterogenous with respect to study population, sample size, study design, methodological quality, mode of TENS, treatment duration, method of administration and outcome measures used. In one RCT, there were no significant differences between TENS and placebo in women with chronic pain secondary to breast cancer treatment. In the other RCT, there were no significant differences between acupuncture-type TENS and sham in palliative care patients; this study was underpowered. Authors' conclusions The results of this systematic review are inconclusive due to a lack of suitable RCTs. Large multi-centre RCTs are required to assess the value of TENS in the management of cancer-related pain in adults

    Historical Arctic Logbooks Provide Insights into Past Diets and Climatic Responses of Cod

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    Gadus morhua (Atlantic cod) stocks in the Barents Sea are currently at levels not seen since the 1950s. Causes for the population increase last century, and understanding of whether such large numbers will be maintained in the future, are unclear. To explore this, we digitised and interrogated historical cod catch and diet datasets from the Barents Sea. Seventeen years of catch data and 12 years of prey data spanning 1930–1959 cover unexplored spatial and temporal ranges, and importantly capture the end of a previous warm period, when temperatures were similar to those currently being experienced. This study aimed to evaluate cod catch per unit effort and prey frequency in relation to spatial, temporal and environmental variables. There was substantial spatio-temporal heterogeneity in catches through the time series. The highest catches were generally in the 1930s and 1940s, although at some localities more cod were recorded late in the 1950s. Generalized Additive Models showed that environmental, spatial and temporal variables are all valuable descriptors of cod catches, with the highest occurring from 15–45°E longitude and 73–77°N latitude, at bottom temperatures between 2 and 4°C and at depths between 150 and 250 m. Cod diets were highly variable during the study period, with frequent changes in the relative frequencies of different prey species, particularly Mallotus villosus (capelin). Environmental variables were particularly good at describing the importance of capelin and Clupea harengus (herring) in the diet. These new analyses support existing knowledge about how the ecology of the region is controlled by climatic variability. When viewed in combination with more recent data, these historical relationships will be valuable in forecasting the future of Barents Sea fisheries, and in understanding how environments and ecosystems may respond

    Dissipation and mixing during the onset of stratification in a temperate lake, Windermere

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    Acoustic Doppler Current Profilers and chains of temperature sensors were used to observe the spring transition to stable stratification over a 55 day period in a temperate lake. Observations of the flow structure were complemented by measurements of dissipation, based on the Structure Function method, near the lake bed and in the upper part of the water column. During complete vertical mixing, wind-driven motions had horizontally isotropic velocities with roughly equal barotropic and baroclinic kinetic energy. Dissipation was closely correlated with the wind-speed cubed, indicating law of the wall scaling, and had peak values of ~1 x 10-5.5 W kg-1 at 10 m depth during maximum wind forcing (W~ 15 m s-1). As stratification developed, the flow evolved into a predominantly baroclinic regime dominated by the first mode internal seiche, with root mean square (rms) axial flow speeds of ~2-3 cm-1; ~ 2.5-times the transverse component. At 2.8 m above the bed, most of the dissipation occurred in a number of strong maxima coinciding with peaks of near-bed flow. In the pycnocline, dissipation was low most of the time, but with pronounced maxima (reaching ~1 x 10-5 W kg-1) closely related to the local velocity shear. The downward diffusive heat flux across the pycnocline over 27.5 days accounted for ~ 70% of the temperature rise in the water column below. Total lake kinetic energy increased by a factor of 3 between mixed and stratified regimes, in spite of reduced wind forcing, indicating less efficient damping in stable conditions

    Synchronization of spin-driven limit cycle oscillators optically levitated in vacuum

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    We explore, experimentally and theoretically, the emergence of coherent coupled oscillations and synchronization between a pair of non-Hermitian, stochastic, opto-mechanical oscillators, levitated in vacuum. Each oscillator consists of a polystyrene microsphere trapped in a circularly polarized, counter-propagating Gaussian laser beam. Non-conservative, azimuthal forces, deriving from inhomogeneous optical spin, push the micro-particles out of thermodynamic equilibrium. For modest optical powers each particle shows a tendency towards orbital circulation. Initially, their stochastic motion is weakly correlated. As the power is increased, the tendency towards orbital circulation strengthens and the motion of the particles becomes highly correlated. Eventually, centripetal forces overcome optical gradient forces and the oscillators undergo a collective Hopf bifurcation. For laser powers exceeding this threshold, a pair of limit cycles appear, which synchronize due to weak optical and hydrodynamic interactions. In principle, arrays of such Non-Hermitian elements can be arranged, paving the way for opto-mechanical topological materials or, possibly, classical time crystals. In addition, the preparation of synchronized states in levitated optomechanics could lead to new and robust sensors or alternative routes to the entanglement of macroscopic objects
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