384 research outputs found

    Using Statistical Techniques to Predict Non-Pecuniary Damage Awards in Personal Injury Cases

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    The real issue in personal injury cases is often damages. Our concepts and law relating to negligence and other aspects of personal injury are sufficiently developed that parties can often agree upon who is at fault. Yet damages law, for all the cases and principles which have been decided, remains the least intelligible and thus the least predictable for parties and their counsel. When parties have to go to trial in a personal injury case, it is often primarily to decide who should pay what

    The Allen Telescope Array: The First Widefield, Panchromatic, Snapshot Radio Camera for Radio Astronomy and SETI

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    The first 42 elements of the Allen Telescope Array (ATA-42) are beginning to deliver data at the Hat Creek Radio Observatory in Northern California. Scientists and engineers are actively exploiting all of the flexibility designed into this innovative instrument for simultaneously conducting surveys of the astrophysical sky and conducting searches for distant technological civilizations. This paper summarizes the design elements of the ATA, the cost savings made possible by the use of COTS components, and the cost/performance trades that eventually enabled this first snapshot radio camera. The fundamental scientific program of this new telescope is varied and exciting; some of the first astronomical results will be discussed.Comment: Special Issue of Proceedings of the IEEE: "Advances in Radio Telescopes", Baars,J. Thompson,R., D'Addario, L., eds, 2009, in pres

    Non-destructive optical measurement of relative phase between two Bose condensates

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    We study the interaction of light with two Bose condensates as an open quantum system. The two overlapping condensates occupy two different Zeeman sublevels and two driving light beams induce a coherent quantum tunneling between the condensates. We derive the master equation for the system. It is shown that stochastic simulations of the measurements of spontaneously scattered photons establish the relative phase between two Bose condensates, even though the condensates are initially in pure number states. These measurements are non-destructive for the condensates, because only light is scattered, but no atoms are removed from the system. Due to the macroscopic quantum interference the detection rate of photons depends substantially on the relative phase between the condensates. This may provide a way to distinguish, whether the condensates are initially in number states or in coherent states.Comment: 26 pages, RevTex, 8 postscript figures, 1 MacBinary eps-figur

    The Allen Telescope Array Pi GHz Sky Survey I. Survey Description and Static Catalog Results for the Bootes Field

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    The Pi GHz Sky Survey (PiGSS) is a key project of the Allen Telescope Array. PiGSS is a 3.1 GHz survey of radio continuum emission in the extragalactic sky with an emphasis on synoptic observations that measure the static and time-variable properties of the sky. During the 2.5-year campaign, PiGSS will twice observe ~250,000 radio sources in the 10,000 deg^2 region of the sky with b > 30 deg to an rms sensitivity of ~1 mJy. Additionally, sub-regions of the sky will be observed multiple times to characterize variability on time scales of days to years. We present here observations of a 10 deg^2 region in the Bootes constellation overlapping the NOAO Deep Wide Field Survey field. The PiGSS image was constructed from 75 daily observations distributed over a 4-month period and has an rms flux density between 200 and 250 microJy. This represents a deeper image by a factor of 4 to 8 than we will achieve over the entire 10,000 deg^2. We provide flux densities, source sizes, and spectral indices for the 425 sources detected in the image. We identify ~100$ new flat spectrum radio sources; we project that when completed PiGSS will identify 10^4 flat spectrum sources. We identify one source that is a possible transient radio source. This survey provides new limits on faint radio transients and variables with characteristic durations of months.Comment: Accepted for publication in ApJ; revision submitted with extraneous figure remove

    The Allen Telescope Array Twenty-centimeter Survey - A 690-Square-Degree, 12-Epoch Radio Dataset - I: Catalog and Long-Duration Transient Statistics

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    We present the Allen Telescope Array Twenty-centimeter Survey (ATATS), a multi-epoch (12 visits), 690 square degree radio image and catalog at 1.4GHz. The survey is designed to detect rare, very bright transients as well as to verify the capabilities of the ATA to form large mosaics. The combined image using data from all 12 ATATS epochs has RMS noise sigma = 3.94mJy / beam and dynamic range 180, with a circular beam of 150 arcsec FWHM. It contains 4408 sources to a limiting sensitivity of S = 20 mJy / beam. We compare the catalog generated from this 12-epoch combined image to the NRAO VLA Sky Survey (NVSS), a legacy survey at the same frequency, and find that we can measure source positions to better than ~20 arcsec. For sources above the ATATS completeness limit, the median flux density is 97% of the median value for matched NVSS sources, indicative of an accurate overall flux calibration. We examine the effects of source confusion due to the effects of differing resolution between ATATS and NVSS on our ability to compare flux densities. We detect no transients at flux densities greater than 40 mJy in comparison with NVSS, and place a 2-sigma upper limit on the transient rate for such sources of 0.004 per square degree. These results suggest that the > 1 Jy transients reported by Matsumura et al. (2009) may not be true transients, but rather variable sources at their flux density threshold.Comment: 41 pages, 19 figures, ApJ accepted; corrected minor typo in Table

    The Allen Telescope Array Pi GHz Sky Survey I. Survey Description and Static Catalog Results for the Bootes Field

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    The Pi GHz Sky Survey (PiGSS) is a key project of the Allen Telescope Array. PiGSS is a 3.1 GHz survey of radio continuum emission in the extragalactic sky with an emphasis on synoptic observations that measure the static and time-variable properties of the sky. During the 2.5-year campaign, PiGSS will twice observe ~250,000 radio sources in the 10,000 deg^2 region of the sky with b > 30 deg to an rms sensitivity of ~1 mJy. Additionally, sub-regions of the sky will be observed multiple times to characterize variability on time scales of days to years. We present here observations of a 10 deg^2 region in the Bootes constellation overlapping the NOAO Deep Wide Field Survey field. The PiGSS image was constructed from 75 daily observations distributed over a 4-month period and has an rms flux density between 200 and 250 microJy. This represents a deeper image by a factor of 4 to 8 than we will achieve over the entire 10,000 deg^2. We provide flux densities, source sizes, and spectral indices for the 425 sources detected in the image. We identify ~100$ new flat spectrum radio sources; we project that when completed PiGSS will identify 10^4 flat spectrum sources. We identify one source that is a possible transient radio source. This survey provides new limits on faint radio transients and variables with characteristic durations of months.Comment: Accepted for publication in ApJ; revision submitted with extraneous figure remove

    Achieving temperature-size changes in a unicellular organism.

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    The temperature-size rule (TSR) is an intraspecific phenomenon describing the phenotypic plastic response of an organism size to the temperature: individuals reared at cooler temperatures mature to be larger adults than those reared at warmer temperatures. The TSR is ubiquitous, affecting >80% species including uni- and multicellular groups. How the TSR is established has received attention in multicellular organisms, but not in unicells. Further, conceptual models suggest the mechanism of size change to be different in these two groups. Here, we test these theories using the protist Cyclidium glaucoma. We measure cell sizes, along with population growth during temperature acclimation, to determine how and when the temperature-size changes are achieved. We show that mother and daughter sizes become temporarily decoupled from the ratio 2:1 during acclimation, but these return to their coupled state (where daughter cells are half the size of the mother cell) once acclimated. Thermal acclimation is rapid, being completed within approximately a single generation. Further, we examine the impact of increased temperatures on carrying capacity and total biomass, to investigate potential adaptive strategies of size change. We demonstrate no temperature effect on carrying capacity, but maximum supported biomass to decrease with increasing temperature

    Structural Geology and the Seismotectonics of the 2004 Great Sumatran Earthquake

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    The paper sets out a method for structural analysis of seismotectonic data using centroid moment tensors and associated hypocenters from the Global Centroid Moment Tensor project, here illustrated for aftershocks from the 2004 great Sumatran earthquake. We show that the Sumatran segments of the megathrust were subject to compression in a direction near to orthogonal with the margin trend, consistent with the effect of relative movement of the adjacent tectonic plates. In contrast, the crust above the Andaman Sea segments was subject to margin-orthogonal extension, consistent with motion toward the gravitational potential well accumulated due to prior lateral (westward) rollback of the subducting edge of the northward moving Indian plate. Since this potential well is largely defined by topography, this episode of margin-orthogonal extension is at least in part “gravity driven.” It did not last long. Within 15 months, an earthquake cluster across an Andaman Sea spreading segment showed a return to kinematics driven by relative plate motion. The transition can be explained if fluid activity temporarily reduced basal friction (or effective stress) but then led to healing so that the megathrust once again began to develop friction-locked segments. The influence of slab rollback is in developing a gravitational potential well facing the megathrust, hence drawing the overriding crust toward it in the immediate postrupture phase while the megathrust is in a weakened state. Plate tectonics dominates during interseismic gaps, once the megathrust heals, and regains frictional resistance.y. The authors acknowledge funding support from the Australian Research Council: Discovery Project DP120103554 “A unified model for the closure dynamics of ancient Tethys constrained by geodesy, structural geology, argon geochronology and tectonic reconstruction” and Linkage Project LP130100134 “Where to find giant porphyry and epithermal gold and copper deposits.” The research was also supported by the “Satellites, Seismometers and Mass Spectrometers” initiative within the Research School of Earth Sciences at ANU. Bob Engdahl is thanked for his support during earlier versions and for providing data

    Public awareness and healthcare professional advice for obesity as a risk factor for cancer in the UK:a cross-sectional survey

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    BACKGROUND: Overweight and obesity is the second biggest preventable cause of cancer after smoking, causing ~3.4 million deaths worldwide. This study provides current UK data on awareness of the link between obesity and cancer by socio-demographic factors, including BMI, and explores to what degree healthcare professionals provide weight management advice to patients. METHODS: Cross-sectional survey of 3293 adults completed an online survey in February/March 2016, weighted to be representative of the UK population aged 18+. RESULTS: Public awareness of the link between obesity and cancer is low (25.4% unprompted and 57.5% prompted). Higher levels of awareness existed for least deprived groups (P < 0.001), compared to more deprived groups. Most respondents had seen a healthcare practitioner in the past 12 months (91.6%) and 17.4% had received advice about their weight, although 48.4% of the sample were overweight/obese. CONCLUSION: Cancer is not at the forefront of people’s minds when considering health conditions associated with overweight or obesity. Socio-economic disparities exist in health knowledge across the UK population, with adults from more affluent groups being most aware. Healthcare professionals are uniquely positioned to provide advice about weight, but opportunities for intervention are currently under-utilized in healthcare settings
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