498 research outputs found
Urban growth drivers in a Europe of sticky people and implicit boundaries
We investigate urban GDP pc growth across the EU12 using data for functionally defined cities - rather than administrative regions. We test hypotheses on the role of human capital, EU integration and fragmentation of urban government and explore spatial dependence and mechanisms of spatial interaction. Results are acceptable on standard econometric tests without measures of spatial interaction but there is spatial dependence. If variables reflecting spatial adjustment are included, they are statistically significant and eliminate spatial dependence. Not only do the results now provide consistent estimates of parameters, they also support relevant theoretical insights and show national borders are still significant barriers to economic adjustment. People in Europe are sticky so it is unreasonable to assume spatial disparities will disappear. Our findings also imply that cities in Europe form national rather than a single continental system
Science with coffee and hobnobs
Many parents or guardians of primary school pupils have little knowledge of science, and many lack confidence in their ability to help their children, though most welcome the chance to do so. We describe our experiences running a series of meetings in the form of coffee sessions at local primary schools, where parents can increase their knowledge and confidence in the science their children study, and engage in simple experiments with their children to apply the knowledge they gain. We discuss how this programme can be instrumental in improving the profile of scientific education and scientific careers for children of a young age
Flight Operations for the LCROSS Lunar Impactor Mission
The LCROSS (Lunar CRater Observation and Sensing Satellite) mission was conceived as a low-cost means of determining the nature of hydrogen concentrated at the polar regions of the moon. Co-manifested for launch with LRO (Lunar Reconnaissance Orbiter), LCROSS guided its spent Centaur upper stage into the Cabeus crater as a kinetic impactor, and observed the impact flash and resulting debris plume for signs of water and other compounds from a Shepherding Spacecraft. Led by NASA Ames Research Center, LCROSS flight operations spanned 112 days, from June 18 through October 9, 2009. This paper summarizes the experiences from the LCROSS flight, highlights the challenges faced during the mission, and examines the reasons for its ultimate success
Bayesian Methods for Exoplanet Science
Exoplanet research is carried out at the limits of the capabilities of
current telescopes and instruments. The studied signals are weak, and often
embedded in complex systematics from instrumental, telluric, and astrophysical
sources. Combining repeated observations of periodic events, simultaneous
observations with multiple telescopes, different observation techniques, and
existing information from theory and prior research can help to disentangle the
systematics from the planetary signals, and offers synergistic advantages over
analysing observations separately. Bayesian inference provides a
self-consistent statistical framework that addresses both the necessity for
complex systematics models, and the need to combine prior information and
heterogeneous observations. This chapter offers a brief introduction to
Bayesian inference in the context of exoplanet research, with focus on time
series analysis, and finishes with an overview of a set of freely available
programming libraries.Comment: Invited revie
A Comparison Between the Teg 6s and Teg 5000 Analyzers to Assess Coagulation in Trauma Patients
BACKGROUND Trauma-induced coagulopathy is a major driver of mortality following severe injury. Viscoelastic goal-directed resuscitation can reduce mortality after injury. The TEG 5000 system is widely used for viscoelastic testing. However, the TEG 6s system incorporates newer technology, with encouraging results in cardiovascular interventions. The purpose of this study was to validate the TEG 6s system for use in trauma patients. METHODS Multicenter noninvasive observational study for method comparison conducted at 12 US Levels I and II trauma centers. Agreement between the TEG 6s and TEG 5000 systems was examined using citrated kaolin reaction time (CK.R), citrated functional fibrinogen maximum amplitude (CFF.MA), citrated kaolin percent clot lysis at 30 minutes (CK.LY30), citrated RapidTEG maximum amplitude (CRT.MA), and citrated kaolin maximum amplitude (CK.MA) parameters in adults meeting full or limited trauma team criteria. Blood was drawn ≤1 hour after admission. Assays were repeated in duplicate. Reliability (TEG 5000 vs. TEG 6s analyzers) and repeatability (interdevice comparison) was quantified. Linear regression was used to define the relationship between TEG 6s and TEG 5000 devices. RESULTS A total of 475 patients were enrolled. The cohort was predominantly male (68.6%) with a median age of 49 years. Regression line slope estimates (ß) and linear correlation estimates (p) were as follows: CK.R (ß = 1.05, ρ = 0.9), CFF.MA (ß = 0.99, ρ = 0.95), CK.LY30 (ß = 1.01, ρ = 0.91), CRT.MA (TEG 6s) versus CK.MA (TEG 5000) (ß = 1.06, ρ = 0.86) as well as versus CRT.MA (TEG 5000) (ß = 0.93, ρ = 0.93), indicating strong reliability between the devices. Overall, within-device repeatability was better for TEG 6s versus TEG 5000, particularly for CFF.MA and CK.LY30. CONCLUSION The TEG 6s device appears to be highly reliable for use in trauma patients, with close correlation to the TEG 5000 device and equivalent/improved within-device reliability. Given the potential advantages of using the TEG 6s device at the site of care, confirmation of agreement between the devices represents an important advance in diagnostic testing. LEVEL OF EVIDENCE Diagnostic test, level II
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Phase-Coherent Synthesis of Optical Frequencies and Waveforms
Precision phase control of an ultrawide-bandwidth optical-frequency comb has produced remarkable and unexpected progress in both areas of optical-frequency metrology and ultrafast optics. A frequency comb (with 100 MHz spacing) spanning an entire optical octave (\u3e300 THz) has been produced, corresponding to millions of marks on a frequency “ruler” that are stable at the Hz level. The precision comb has been used to establish a simple optical clock based on an optical transition of iodine molecules, providing an rf clock signal with a frequency stability comparable to that of an optical standard, and which is superior to almost all conventional rf sources. To realize a high-power cw optical frequency synthesizer, a separate, widely tunable single-frequency cw laser has been employed to randomly access the stabilized optical comb and lock to any desired comb component. Carrier-envelope phase stabilization of few-cycle optical pulses has recently been realized. This advance in femtosecond technology is important for both extreme non-linear optics and optical-frequency metrology. With two independent femtosecond lasers, we have not only synchronized their relative pulse timing at the femtosecond level, but have also phase-locked their carrier frequencies, thus establishing phase coherence between the two lasers. By coherently stitching the optical bandwidth together, a “synthesized” pulse has been generated with its 2nd-order autocorrelation signal displaying a shorter width than those of the two “parent” lasers
An 800-million-solar-mass black hole in a significantly neutral Universe at redshift 7.5
Quasars are the most luminous non-transient objects known and as a result
they enable studies of the Universe at the earliest cosmic epochs. Despite
extensive efforts, however, the quasar ULAS J1120+0641 at z=7.09 has remained
the only one known at z>7 for more than half a decade. Here we report
observations of the quasar ULAS J134208.10+092838.61 (hereafter J1342+0928) at
redshift z=7.54. This quasar has a bolometric luminosity of 4e13 times the
luminosity of the Sun and a black hole mass of 8e8 solar masses. The existence
of this supermassive black hole when the Universe was only 690 million years
old---just five percent of its current age---reinforces models of early
black-hole growth that allow black holes with initial masses of more than about
1e4 solar masses or episodic hyper-Eddington accretion. We see strong evidence
of absorption of the spectrum of the quasar redwards of the Lyman alpha
emission line (the Gunn-Peterson damping wing), as would be expected if a
significant amount (more than 10 per cent) of the hydrogen in the intergalactic
medium surrounding J1342+0928 is neutral. We derive a significant fraction of
neutral hydrogen, although the exact fraction depends on the modelling.
However, even in our most conservative analysis we find a fraction of more than
0.33 (0.11) at 68 per cent (95 per cent) probability, indicating that we are
probing well within the reionization epoch of the Universe.Comment: Updated to match the final journal versio
Student Employment: Linking College and the Workplace
The focus of National Student Employment Association (formerly the National Association of Student Employment Administrators, or NASEA) publications has always been on students in transition. From the freshman moving from high school to higher education, to the senior attempting the transition to professional employment and financial independence, we always have explored how students can better accomplish these linking experiences. Student employment is a hybrid, serving as a bridge between work and school, and ultimately, a link between school and full-time work. Student employment links elements of financial aid, career development, academic learning, experiential education, and personal development. Student employment, in all of these ways, is a bridge, moving the student from point A to point B. Because of this variety, any publication on student employment must necessarily speak to diverse themes. We have organized this publication in four sections: an introduction followed by three themed sections.https://digitalcommons.brockport.edu/bookshelf/1000/thumbnail.jp
Aptamer-based multiplexed proteomic technology for biomarker discovery
Interrogation of the human proteome in a highly multiplexed and efficient manner remains a coveted and challenging goal in biology. We present a new aptamer-based proteomic technology for biomarker discovery capable of simultaneously measuring thousands of proteins from small sample volumes (15 [mu]L of serum or plasma). Our current assay allows us to measure ~800 proteins with very low limits of detection (1 pM average), 7 logs of overall dynamic range, and 5% average coefficient of variation. This technology is enabled by a new generation of aptamers that contain chemically modified nucleotides, which greatly expand the physicochemical diversity of the large randomized nucleic acid libraries from which the aptamers are selected. Proteins in complex matrices such as plasma are measured with a process that transforms a signature of protein concentrations into a corresponding DNA aptamer concentration signature, which is then quantified with a DNA microarray. In essence, our assay takes advantage of the dual nature of aptamers as both folded binding entities with defined shapes and unique sequences recognizable by specific hybridization probes. To demonstrate the utility of our proteomics biomarker discovery technology, we applied it to a clinical study of chronic kidney disease (CKD). We identified two well known CKD biomarkers as well as an additional 58 potential CKD biomarkers. These results demonstrate the potential utility of our technology to discover unique protein signatures characteristic of various disease states. More generally, we describe a versatile and powerful tool that allows large-scale comparison of proteome profiles among discrete populations. This unbiased and highly multiplexed search engine will enable the discovery of novel biomarkers in a manner that is unencumbered by our incomplete knowledge of biology, thereby helping to advance the next generation of evidence-based medicine
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