849 research outputs found
Rotating Resonator-Oscillator Experiments to Test Lorentz Invariance in Electrodynamics
In this work we outline the two most commonly used test theories (RMS and
SME) for testing Local Lorentz Invariance (LLI) of the photon. Then we develop
the general framework of applying these test theories to resonator experiments
with an emphasis on rotating experiments in the laboratory. We compare the
inherent sensitivity factors of common experiments and propose some new
configurations. Finally we apply the test theories to the rotating cryogenic
experiment at the University of Western Australia, which recently set new
limits in both the RMS and SME frameworks [hep-ph/0506074].Comment: Submitted to Lecture Notes in Physics, 36 pages, minor modifications,
updated list of reference
Size and emotion or depth and emotion? Evidence, using Matryoshka (Russian) dolls, of children using physical depth as a proxy for emotional charge
Background: The size and emotion effect is the tendency for children to draw people and other objects with a positive emotional charge larger than those with a negative or neutral charge. Here we explored the novel idea that drawing size might be acting as a proxy for depth (proximity).Methods: Forty-two children (aged 3-11 years) chose, from 2 sets of Matryoshka (Russian) dolls, a doll to represent a person with positive, negative or neutral charge, which they placed in front of themselves on a sheet of A3 paper. Results: We found that the children used proximity and doll size, to indicate emotional charge. Conclusions: These findings are consistent with the notion that in drawings, children are using size as a proxy for physical closeness (proximity), as they attempt with varying success to put positive charged items closer to, or negative and neutral charge items further away from, themselves
Recent Experimental Tests of Special Relativity
We review our recent Michelson-Morley (MM) and Kennedy-Thorndike (KT)
experiment, which tests Lorentz invariance in the photon sector, and report
first results of our ongoing atomic clock test of Lorentz invariance in the
matter sector. The MM-KT experiment compares a cryogenic microwave resonator to
a hydrogen maser, and has set the most stringent limit on a number of
parameters in alternative theories to special relativity. We also report first
results of a test of Lorentz invariance in the SME (Standard Model Extension)
matter sector, using Zeeman transitions in a laser cooled Cs atomic fountain
clock. We describe the experiment together with the theoretical model and
analysis. Recent experimental results are presented and we give a first
estimate of components of the parameters of the SME matter
sector. A full analysis of systematic effects is still in progress, and will be
the subject of a future publication together with our final results. If
confirmed, the present limits would correspond to first ever measurements of
some components, and improvements by 11 and 14 orders of
magnitude on others.Comment: 29 pages. Contribution to Springer Lecture Notes, "Special Relativity
- Will it survive the next 100 years ?", Proceedings, Potsdam, 200
An overview of the mid-infrared spectro-interferometer MATISSE: science, concept, and current status
MATISSE is the second-generation mid-infrared spectrograph and imager for the
Very Large Telescope Interferometer (VLTI) at Paranal. This new interferometric
instrument will allow significant advances by opening new avenues in various
fundamental research fields: studying the planet-forming region of disks around
young stellar objects, understanding the surface structures and mass loss
phenomena affecting evolved stars, and probing the environments of black holes
in active galactic nuclei. As a first breakthrough, MATISSE will enlarge the
spectral domain of current optical interferometers by offering the L and M
bands in addition to the N band. This will open a wide wavelength domain,
ranging from 2.8 to 13 um, exploring angular scales as small as 3 mas (L band)
/ 10 mas (N band). As a second breakthrough, MATISSE will allow mid-infrared
imaging - closure-phase aperture-synthesis imaging - with up to four Unit
Telescopes (UT) or Auxiliary Telescopes (AT) of the VLTI. Moreover, MATISSE
will offer a spectral resolution range from R ~ 30 to R ~ 5000. Here, we
present one of the main science objectives, the study of protoplanetary disks,
that has driven the instrument design and motivated several VLTI upgrades
(GRA4MAT and NAOMI). We introduce the physical concept of MATISSE including a
description of the signal on the detectors and an evaluation of the expected
performances. We also discuss the current status of the MATISSE instrument,
which is entering its testing phase, and the foreseen schedule for the next two
years that will lead to the first light at Paranal.Comment: SPIE Astronomical Telescopes and Instrumentation conference, June
2016, 11 pages, 6 Figure
Scanning Angle Plasmon Waveguide Resonance Raman Spectroscopy for the Analysis of Thin Polystyrene Films
Scanning angle (SA) Raman spectroscopy was used to characterize thin polymer films at a sapphire/50 nm gold film/polystyrene/air interface. When the polymer thickness is greater than âŒ260 nm, this interface behaves as a plasmon waveguide; Raman scatter is greatly enhanced with both p- and s-polarized excitation compared to an interface without the gold film. In this study, the reflected light intensities from the interface and Raman spectra were collected as a function of incident angle for three samples with different polystyrene thicknesses. The Raman peak areas were well modeled with the calculated mean-square electric field (MSEF) integrated over the polymer film at varying incident angles. A 412 nm polystyrene plasmon waveguide generated 3.34Ă the Raman signal at 40.52° (the plasmon waveguide resonance angle) compared to the signal measured at 70.4° (the surface plasmon resonance angle). None of the studied polystyrene plasmon waveguides produced detectable Raman scatter using a 180° backscatter collection geometry, demonstrating the sensitivity of the SA Raman technique. The data highlight the ability to measure polymer thickness, chemical content, and, when combined with calculations of MSEF as a function of distance from the interface, details of polymer structure and order. The SA Raman spectroscopy thickness measurements agreed with those obtained from optical interferometery with an average difference of 2.6%. This technique has the potential to impact the rapidly developing technologies utilizing metal/polymer films for energy storage and electronic devices
What determines how we see nature? Perceptions of naturalness in designed urban green spaces
1. The multiple benefits of ânatureâ for human health and well-being have been documented at an increasing rate over the past 30 years. A growing body of research also demonstrates the positive well-being benefits of nature-connectedness. There is, however, a lack of evidence about how people's subjective nature experience relates to deliberately designed and managed urban green infrastructure (GI) with definable âobjectiveâ characteristics such as vegetation type, structure and density. Our study addresses this gap.2. Site users (n = 1411) were invited to walk through woodland, shrub and herbaceous planting at three distinctive levels of planting structure at 31 sites throughout England, whilst participating in a self-guided questionnaire survey assessing reactions to aesthetics, perceived plant and invertebrate biodiversity, restorative effect, nature-connectedness and socio-demographic characteristics.3. There was a significant positive relationship between perceived naturalness and planting structure. Perceived naturalness was also positively related to the perceived plant and invertebrate biodiversity value, participantsâ aesthetic appreciation and the self-reported restorative effect of the planting. A negative relationship was recorded between perceived naturalness and perceived tidiness and care. Our findings showed that participants perceived ânaturalnessâ as biodiverse, attractive and restorative, but not necessarily tidy. Perceived naturalness was also related to participantsâ educational qualifications, gender and nature-connectedness, with women and more nature-connected participants perceiving significantly greater levels of naturalness in the planting.4. These findings are highly significant for policymakers and built environment professionals throughout the world aiming to design, manage and fund urban GI to achieve positive human health and biodiversity outcomes. This applies particularly under austerity approaches to managing urban green spaces where local authorities have experienced cuts in funding and must prioritise and justify GI maintenance practices and regimes
Association of Accelerometry-Measured Physical Activity and Cardiovascular Events in Mobility-Limited Older Adults: The LIFE (Lifestyle Interventions and Independence for Elders) Study.
BACKGROUND:Data are sparse regarding the value of physical activity (PA) surveillance among older adults-particularly among those with mobility limitations. The objective of this study was to examine longitudinal associations between objectively measured daily PA and the incidence of cardiovascular events among older adults in the LIFE (Lifestyle Interventions and Independence for Elders) study. METHODS AND RESULTS:Cardiovascular events were adjudicated based on medical records review, and cardiovascular risk factors were controlled for in the analysis. Home-based activity data were collected by hip-worn accelerometers at baseline and at 6, 12, and 24 months postrandomization to either a physical activity or health education intervention. LIFE study participants (n=1590; age 78.9±5.2 [SD] years; 67.2% women) at baseline had an 11% lower incidence of experiencing a subsequent cardiovascular event per 500 steps taken per day based on activity data (hazard ratio, 0.89; 95% confidence interval, 0.84-0.96; P=0.001). At baseline, every 30 minutes spent performing activities â„500 counts per minute (hazard ratio, 0.75; confidence interval, 0.65-0.89 [P=0.001]) were also associated with a lower incidence of cardiovascular events. Throughout follow-up (6, 12, and 24 months), both the number of steps per day (per 500 steps; hazard ratio, 0.90, confidence interval, 0.85-0.96 [P=0.001]) and duration of activity â„500 counts per minute (per 30 minutes; hazard ratio, 0.76; confidence interval, 0.63-0.90 [P=0.002]) were significantly associated with lower cardiovascular event rates. CONCLUSIONS:Objective measurements of physical activity via accelerometry were associated with cardiovascular events among older adults with limited mobility (summary score >10 on the Short Physical Performance Battery) both using baseline and longitudinal data. CLINICAL TRIAL REGISTRATION:URL: http://www.clinicaltrials.gov. Unique identifier: NCT01072500
Emergency presentation of cancer and short-term mortality
Background:The short-term survival following a cancer diagnosis in England is lower than that in comparable countries, with the difference in excess mortality primarily occurring in the months immediately after diagnosis. We assess the impact of emergency presentation (EP) on the excess mortality in England over the course of the year following diagnosis. Methods:All colorectal and cervical cancers presenting in England and all breast, lung, and prostate cancers in the East of England in 2006-2008 are included. The variation in the likelihood of EP with age, stage, sex, co-morbidity, and income deprivation is modelled. The excess mortality over 0-1, 1-3, 3-6, and 6-12 months after diagnosis and its dependence on these case-mix factors and presentation route is then examined. Results:More advanced stage and older age are predictive of EP, as to a lesser extent are co-morbidity, higher income deprivation, and female sex. In the first month after diagnosis, we observe case-mix-adjusted excess mortality rate ratios of 7.5 (cervical), 5.9 (colorectal), 11.7 (breast ), 4.0 (lung), and 20.8 (prostate) for EP compared with non-EP. Conclusion:Individuals who present as an emergency experience high short-term mortality in all cancer types examined compared with non-EPs. This is partly a case-mix effect but EP remains predictive of short-term mortality even when age, stage, and co-morbidity are accounted for
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