1,029 research outputs found
Burnett-Weaver Debate Volume Two: Operation of the Holy Spirit, Design of Baptism, The Creed Criticised
https://digitalcommons.acu.edu/crs_books/1259/thumbnail.jp
Association of molecules using a resonantly modulated magnetic field
We study the process of associating molecules from atomic gases using a
magnetic field modulation that is resonant with the molecular binding energy.
We show that maximal conversion is obtained by optimising the amplitude and
frequency of the modulation for the particular temperature and density of the
gas. For small modulation amplitudes, resonant coupling of an unbound atom pair
to a molecule occurs at a modulation frequency corresponding to the sum of the
molecular binding energy and the relative kinetic energy of the atom pair. An
atom pair with an off-resonant energy has a probability of association which
oscillates with a frequency and time-varying amplitude which are primarily
dependent on its detuning. Increasing the amplitude of the modulation tends to
result in less energetic atom pairs being resonantly coupled to the molecular
state, and also alters the dynamics of the transfer from continuum states with
off-resonant energies. This leads to maxima and minima in the total conversion
from the gas as a function of the modulation amplitude. Increasing the
temperature of the gas leads to an increase in the modulation frequency
providing the best fit to the thermal distribution, and weakens the resonant
frequency dependence of the conversion. Mean-field effects can alter the
optimal modulation frequency and lead to the excitation of higher modes. Our
simulations predict that resonant association can be effective for binding
energies of order MHz.Comment: 8 pages latex, figures revised, references updated and typos
correcte
A Look at the Future: Teachers in Non-Traditional Adult Reading Programs
Currently, the job market for those equipped to teach reading and reading related skills to older adolescents and adults in non-school settings is clearly changing and possibly expanding while the demand for teachers to teach only in traditional school-based settings is declining
Submarine groundwater discharge: updates on its measurement techniques, geophysical drivers, magnitudes, and effects
The number of studies concerning Submarine Groundwater Discharge (SGD) grew quickly as we entered the twenty-first century. Many hydrological and oceanographic processes that drive and influence SGD were identified and characterized during this period. These processes included tidal effects on SGD, water and solute fluxes, biogeochemical transformations through the subterranean estuary, and material transport via SGD from land to sea. Here we compile and summarize the significant progress in SGD assessment methodologies, considering both the terrestrial and marine driving forces, and local as well as global evaluations of groundwater discharge with an emphasis on investigations published over the past decade. Our treatment presents the state-of-the-art progress of SGD studies from geophysical, geochemical, bio-ecological, economic, and cultural perspectives. We identify and summarize remaining research questions, make recommendations for future research directions, and discuss potential future challenges, including impacts of climate change on SGD and improved estimates of the global magnitude of SGD
Low-Cost Data Acquisition Card for School-Network Cosmic Ray Detectors
The Cosmic Ray Observatory Project (CROP) at University of Nebraska/Lincoln
and the Washington Area Large-scale Time coincidence Array (WALTA) at
University of Washington/Seattle are among several outreach projects siting
cosmic-ray detectors at local high schools in cities around North America, to
study the origins and interactions of high-energy cosmic rays. In a
collaboration between QuarkNet, the outreach program based at Fermilab, CROP,
and WALTA, a low-cost data acquisition electronics card has been developed to
collect and synchronize the data from each detector site. The cost for each
card is under US$500 for parts, functionally replacing much more expensive
electronics crates and modules at each high school site. The card has 4 analog
discriminator inputs for photo-multiplier tube signals, a 4-channel
Time-to-Digital converter for local coincidence and time-over-threshold
measurements at 0.75 ns resolution, programmable trigger logic via a CPLD and
microcontroller, and a built-in low-cost GPS receiver/antenna module (via
external cable) to provide event trigger time stamps at better than 100 ns
accuracy. Temperature sensors and a barometer are also integrated to record
environmental data along with the counter data. The card connects to any PC or
laptop via a standard RS-232 serial port for data output and control. The
microcontroller and CPLD are field programmable and therefore make the card
functionality flexible and easy to upgrade.Comment: 4 pages, 4 figures, 1 table. Presented by R. J. Wilkes at "IEEE-NSS
2003", Paper N8-1, Portland, OR, November 2003. Submitted to Trans. IEE
Extracting science from surveys of our Galaxy
Our knowledge of the Galaxy is being revolutionised by a series of
photometric, spectroscopic and astrometric surveys. Already an enormous body of
data is available from completed surveys, and data of ever increasing quality
and richness will accrue at least until the end of this decade. To extract
science from these surveys we need a class of models that can give probability
density functions in the space of the observables of a survey -- we should not
attempt to "invert" the data from the space of observables into the physical
space of the Galaxy. Currently just one class of model has the required
capability, so-called "torus models". A pilot application of torus models to
understanding the structure of the Galaxy's thin and thick discs has already
produced two significant results: a major revision of our best estimate of the
Sun's velocity with respect to the Local Standard of Rest, and a successful
prediction of the way in which the vertical velocity dispersion in the disc
varies with distance from the Galactic plane.Comment: 13 pages. Invited review to appear in Pramana - journal of physics
(Indian Academy of Sciences
Data Integration Model for Air Quality: A Hierarchical Approach to the Global Estimation of Exposures to Ambient Air Pollution
This is the author accepted manuscript. Available from arXiv via the URL in this record.Air pollution is a major risk factor for global health, with both ambient and household air pollution contributing substantial components of the overall global disease burden. One of the key drivers of adverse health effects is fine particulate matter ambient pollution (PM2:5) to which an estimated 3 million deaths can be attributed annually. The primary source of information for estimating exposures has been measurements from ground monitoring networks but, although coverage is increasing, there remain regions in which monitoring is limited. Ground monitoring data therefore needs to be supplemented with information from other sources, such as satellite retrievals of aerosol optical depth and chemical transport models. A hierarchical modelling approach for integrating data from multiple sources is proposed allowing spatially-varying relationships between ground measurements and other factors that estimate air quality. Set within a Bayesian framework, the resulting Data Integration Model for Air Quality (DIMAQ) is used to estimate exposures, together with associated measures of uncertainty, on a high resolution grid covering the entire world. Bayesian analysis on this scale can be computationally challenging and here approximate Bayesian inference is performed using Integrated Nested Laplace Approximations. Model selection and assessment is performed by cross-validation with the final model offering substantial increases in predictive accuracy, particularly in regions where there is sparse ground monitoring, when compared to previous approaches: root mean square error (RMSE) reduced from 17.1 to 10.7, and population weighted RMSE from 23.1 to 12.1 gm3. Based on summaries of the posterior distributions for each grid cell, it is estimated that 92% of the worldâs population reside in areas exceeding the World Health Organizationâs Air Quality Guidelines.Matthew Lloyd Thomas is supported by a scholarship from the EPSRC Centre for Doctoral Training in Statistical Applied Mathematics at Bath (SAMBa), under the project EP/L015684/1. Amelia Jobling was supported for this work by WHO contracts APW 201255146 and 201255393
A randomized assessment of adding the kinase inhibitor lestaurtinib to first-line chemotherapy for FLT3-mutated AML
The clinical benefit of adding FMS-like tyrosine kinase-3 (FLT3)-directed small molecule therapy to standard first-line treatment of acute myeloid leukemia (AML) has not yet been established. As part of the UK AML15 and AML17 trials, patients with previously untreated AML and confirmed FLT3-activating mutations, mostly younger than 60 years, were randomly assigned either to receive oral lestaurtinib (CEP701) or not after each of 4 cycles of induction and consolidation chemotherapy. Lestaurtinib was commenced 2 days after completing chemotherapy and administered in cycles of up to 28 days. The trials ran consecutively. Primary endpoints were overall survival in AML15 and relapse-free survival in AML17; outcome data were meta-analyzed. Five hundred patients were randomly assigned between lestaurtinib and control: 74% had FLT3-internal tandem duplication mutations, 23% FLT3âtyrosine kinase domain point mutations, and 2% both types. No significant differences were seen in either 5-year overall survival (lestaurtinib 46% vs control 45%; hazard ratio, 0.90; 95% CI 0.70-1.15; P = .3) or 5-year relapse-free survival (40% vs 36%; hazard ratio, 0.88; 95% CI 0.69-1.12; P = .3). Exploratory subgroup analysis suggested survival benefit with lestaurtinib in patients receiving concomitant azole antifungal prophylaxis and gemtuzumab ozogamicin with the first course of chemotherapy. Correlative studies included analysis of in vivo FLT3 inhibition by plasma inhibitory activity assay and indicated improved overall survival and significantly reduced rates of relapse in lestaurtinib-treated patients who achieved sustained greater than 85% FLT3 inhibition. In conclusion, combining lestaurtinib with intensive chemotherapy proved feasible in younger patients with newly diagnosed FLT3-mutated AML, but yielded no overall clinical benefit. The improved clinical outcomes seen in patients achieving sustained FLT3 inhibition encourage continued evaluation of FLT3-directed therapy alongside front-line AML treatment. The UK AML15 and AML17 trials are registered at www.isrctn.com/ISRCTN17161961 and www.isrctn.com/ISRCTN55675535 respectively
Observation of an Efimov spectrum in an atomic system
In 1970 V. Efimov predicted a puzzling quantum-mechanical effect that is
still of great interest today. He found that three particles subjected to a
resonant pairwise interaction can join into an infinite number of loosely bound
states even though each particle pair cannot bind. Interestingly, the
properties of these aggregates, such as the peculiar geometric scaling of their
energy spectrum, are universal, i.e. independent of the microscopic details of
their components. Despite an extensive search in many different physical
systems, including atoms, molecules and nuclei, the characteristic spectrum of
Efimov trimer states still eludes observation. Here we report on the discovery
of two bound trimer states of potassium atoms very close to the Efimov
scenario, which we reveal by studying three-particle collisions in an ultracold
gas. Our observation provides the first evidence of an Efimov spectrum and
allows a direct test of its scaling behaviour, shedding new light onto the
physics of few-body systems.Comment: 10 pages, 3 figures, 1 tabl
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