6,472 research outputs found
Preparing oxidizer coated metal fuel particles
A solid propellant composition of improved efficiency is described which includes an oxidizer containing ammonium perchlorate, and a powered metal fuel, preferably aluminum or beryllium, in the form of a composite. The metal fuel is contained in the crystalline lattice framework of the oxidizer, as well as within the oxidizer particles, and is disposed in the interstices between the oxidizer particles of the composition. The propellant composition is produced by a process comprising the crystallization of ammonium perchlorate in water, in the presence of finely divided aluminum or beryllium. A suitable binder is incorporated in the propellant composition to bind the individual particles of metal with the particles of oxidizer containing occluded metal
Reverse Mathematics and Algebraic Field Extensions
This paper analyzes theorems about algebraic field extensions using the
techniques of reverse mathematics. In section 2, we show that
is equivalent to the ability to extend -automorphisms of field extensions to
automorphisms of , the algebraic closure of . Section 3 explores
finitary conditions for embeddability. Normal and Galois extensions are
discussed in section 4, and the Galois correspondence theorems for infinite
field extensions are treated in section 5.Comment: 25 page
A Recursive Algorithm for Computing Inferences in Imprecise Markov Chains
We present an algorithm that can efficiently compute a broad class of
inferences for discrete-time imprecise Markov chains, a generalised type of
Markov chains that allows one to take into account partially specified
probabilities and other types of model uncertainty. The class of inferences
that we consider contains, as special cases, tight lower and upper bounds on
expected hitting times, on hitting probabilities and on expectations of
functions that are a sum or product of simpler ones. Our algorithm exploits the
specific structure that is inherent in all these inferences: they admit a
general recursive decomposition. This allows us to achieve a computational
complexity that scales linearly in the number of time points on which the
inference depends, instead of the exponential scaling that is typical for a
naive approach
Reconciliation of object interaction models
This paper presents Reconciliation+, a
tool-supported method which identifies overlaps
between models of different object interactions
expressed as UML sequence and/or collaboration
diagrams, checks whether the overlapping elements
of these models satisfy specific consistency rules,
and guides developers in handling these
inconsistencies. The method also keeps track of the
decisions made and the actions taken in the process
of managing inconsistencies
Sidereal anisotropy of cosmic rays
The data of the ionization chamber in Yakutsk for 1954 to 1984 are analyzed. A false sidereal variation caused by the second spherical harmonic in cosmic ray distribution was found and it has the amplitude 0.020 plus or minus 0.002%. The sidereal anisotropy with a very small amplitude (not more than 0.005%) was observed to exist
Baryons in QCD_{AS} at Large N_c: A Roundabout Approach
QCD_{AS}, a variant of large N_c QCD in which quarks transform under the
color two-index antisymmetric representation, reduces to standard QCD at N_c =
3 and provides an alternative to the usual large N_c extrapolation that uses
fundamental representation quarks. Previous strong plausibility arguments
assert that the QCD_{AS} baryon mass scales as N_c^2; however, the complicated
combinatoric problem associated with quarks carrying two color indices impeded
a complete demonstration. We develop a diagrammatic technique to solve this
problem. The key ingredient is the introduction of an effective multi-gluon
vertex: a "traffic circle" or "roundabout" diagram. We show that arbitrarily
complicated diagrams can be reduced to simple ones with the same leading N_c
scaling using this device, and that the leading contribution to baryon mass
does, in fact, scale as N_c^2.Comment: 9 pages, 9 pdf figures, ReVTeX with pdflate
Crafting A Human Resource Strategy To Foster Organizational Agility: A Case Study
A decade ago, the CEO of Albert Einstein Healthcare Network (AEHN), anticipating a tumultuous and largely unpredictable period in its industry, undertook to convert this organization from one that was basically stable and complacent to one that was agile, “nimble, and change-hardy”. This case study briefly addresses AEHN’s approaches to business strategy and organization design, but focuses primarily on the human resource strategy that emerged over time to foster the successful attainment of organizational agility. Although exploratory, the study suggests a number of lessons for those who are, or will be, studying or trying to create and sustain this promising new organizational paradigm
Applications systems verification and transfer project. Volume 4: Operational applications of satellite snow cover observations. Colorado Field Test Center
The study was conducted on six watersheds ranging in size from 277 km to 3460 km in the Rio Grande and Arkansas River basins of southwestern Colorado. Six years of satellite data in the period 1973-78 were analyzed and snowcover maps prepared for all available image dates. Seven snowmapping techniques were explored; the photointerpretative method was selected as the most accurate. Three schemes to forecast snowmelt runoff employing satellite snowcover observations were investigated. They included a conceptual hydrologic model, a statistical model, and a graphical method. A reduction of 10% in the current average forecast error is estimated when snowcover data in snowmelt runoff forecasting is shown to be extremely promising. Inability to obtain repetitive coverage due to the 18 day cycle of LANDSAT, the occurrence of cloud cover and slow image delivery are obstacles to the immediate implementation of satellite derived snowcover in operational streamflow forecasting programs
Improving Pediatric Provider Preparedness for Postpartum Depression Screening
Background: Postpartum depression (PPD) is one of the most common complications of childbirth, affecting approximately 10-20% of mothers within the child’s first year of life with negative impact on both mother and child. . Pediatric primary care providers have frequent contact over the infant’s first year of life. The American Academy of Pediatrics (AAP) recommends screening mothers for PPD at the 1, 2, 4, and 6-month well-baby visits, yet due to barriers, pediatric providers are not consistently screening for PPD. Barriers include lack of preparedness and knowledge of resources and inadequate time.
Aims of Service Change: To improve pediatric provider preparedness to screen for PPD at a large multi-site pediatric group practice in Southern California and lead to increased screening, detection, and treatment of PPD.
Details of Innovation: The core intervention was provider education regarding recommendations for postpartum depression screening. Provider education also included provider responsibility in identifying PPD, community resources, and an overview of PPD diagnostic criteria. This project assessed provider preparedness using a pre-post education online anonymous survey.
Outcome: Implementation of provider education increased self-reported preparedness to screen for PPD at well-baby visits with an increase of average score in all categories. Knowledge of resources and provider confidence had the most substantial increases.
Discussion: Implementing provider education regarding screening for PPD at well-baby visits is a simple and cost-effective intervention. This leads to improved provider preparedness, potential increased identification of PPD in mothers, and improved overall outcomes for mothers and babies
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