13,722 research outputs found
Simplified methods for calculating photodissociation rates
Simplified methods for calculating the transmission of solar UV radiation and the dissociation coefficients of various molecules are compared. A significant difference sometimes appears in calculations of the individual band, but the total transmission and the total dissociation coefficients integrated over the entire SR (solar radiation) band region agree well between the methods. The ambiguities in the solar flux data affect the calculated dissociation coefficients more strongly than does the method. A simpler method is developed for the purpose of reducing the computation time and computer memory size necessary for storing coefficients of the equations. The new method can reduce the computation time by a factor of more than 3 and the memory size by a factor of more than 50 compared with the Hudson-Mahle method, and yet the result agrees within 10 percent (in most cases much less) with the original Hudson-Mahle results, except for H2O and CO2. A revised method is necessary for these two molecules, whose absorption cross sections change very rapidly over the SR band spectral range
A synoptic description of coal basins via image processing
An existing image processing system is adapted to describe the geologic attributes of a regional coal basin. This scheme handles a map as if it were a matrix, in contrast to more conventional approaches which represent map information in terms of linked polygons. The utility of the image processing approach is demonstrated by a multiattribute analysis of the Herrin No. 6 coal seam in Illinois. Findings include the location of a resource and estimation of tonnage corresponding to constraints on seam thickness, overburden, and Btu value, which are illustrative of the need for new mining technology
Early life growth patterns persist for 12 years and impact pulmonary outcomes in cystic fibrosis
BACKGROUND:
In children with cystic fibrosis (CF), recovery from growth faltering within 2 years of diagnosis (Responders) is associated with better growth and less lung disease at age 6 years. This study examined whether these benefits are sustained through 12 years of age.
METHODS:
Longitudinal growth from 76 children with CF enrolled in the Wisconsin CF Neonatal Screening Project was examined and categorized into 5 groups: R12, R6, and R2, representing Responders who maintained growth improvement to age 12, 6, and 2 years, respectively, and I6 and N6, representing Non-responders whose growth did and did not improve during ages 2-6 years, respectively. Lung disease was evaluated by % predicted forced expiratory volume in one second (FEV1) and chest radiograph (CXR) scores.
RESULTS:
Sixty-two percent were Responders. Within this group, 47% were R12, 28% were R6, and 25% were R2. Among Non-responders, 76% were N6. CF children with meconium ileus (MI) had worse lung function and CXR scores compared to other CF children. Among 53 children with pancreatic insufficiency without MI, R12 had significantly better FEV1 (97-99% predicted) and CXR scores during ages 6-12 years than N6 (89-93% predicted). Both R6 and R2 experienced a decline in FEV1 by ages 10-12 years.
CONCLUSIONS:
Early growth recovery in CF is critical, as malnutrition during infancy tends to persist and catch-up growth after age 2 years is difficult. The longer adequate growth was maintained after early growth recovery, the better the pulmonary outcomes at age 12 years
Efficient white noise sampling and coupling for multilevel Monte Carlo with non-nested meshes
When solving stochastic partial differential equations (SPDEs) driven by
additive spatial white noise, the efficient sampling of white noise
realizations can be challenging. Here, we present a new sampling technique that
can be used to efficiently compute white noise samples in a finite element
method and multilevel Monte Carlo (MLMC) setting. The key idea is to exploit
the finite element matrix assembly procedure and factorize each local mass
matrix independently, hence avoiding the factorization of a large matrix.
Moreover, in a MLMC framework, the white noise samples must be coupled between
subsequent levels. We show how our technique can be used to enforce this
coupling even in the case of non-nested mesh hierarchies. We demonstrate the
efficacy of our method with numerical experiments. We observe optimal
convergence rates for the finite element solution of the elliptic SPDEs of
interest in 2D and 3D and we show convergence of the sampled field covariances.
In a MLMC setting, a good coupling is enforced and the telescoping sum is
respected.Comment: 28 pages, 10 figure
Lucy : Dancing Around The Cabin Door
https://digitalcommons.library.umaine.edu/mmb-vp/5190/thumbnail.jp
Fragmentation, Frustrated Revolt, and Off-Shore Opportunity: A Comparative Examination of Jihadi Mobilization in Central Asia and the South Caucasus
This research presents analysis for identifying common risk and resilience factors that contributed to or hindered Salafi jihadi mobilization of citizens of Central Asia and the South Caucasus and examines the extent to which these factors had differing internal and external outcomes on Salafi jihadi mobilization. Three levels of analysis provide examination of regime characteristics, behavior of jihadi organizations that mobilized individuals from the region, and case studies through interviews in communities affected by jihadi mobilization in Kyrgyzstan and Georgia.
This research reveals that early distinctions in Islamist subnational struggles had oriented violence towards governments within Central Asia, while neighboring struggles in the North Caucasus oriented jihadi participants from Azerbaijan and Georgia largely towards external authorities in the north. Further, this research suggests that the dual phenomena of domestic jihadi manifestation of violence and foreign fighter mobilization to external theatres are inversely related and affected by the patterns of jihadi organizational displacement, co-location with larger entities engaged in conflict abroad, and expansion of organizations seeking new members within these external jihadi theatres. Additionally, state behavior, including state coercive capacity, solidification of elite cooperation, and regime legitimation through the construction of well-curated national identities, has served as a strengthening bulwark against jihadi organizational effectiveness internally in the region. Yet, interview data from this study indicates that state behavior has also engendered notable grievances among ethnic and religious minority populations in areas of jihadi foreign fighter origin. Despite these society-fragmenting perceptions of injustice, prejudice, and lack of trust in governance, grievances have not galvanized into viable sustained internal jihadi action throughout the region. Rather, this research suggests that punitive state pressures on outgroups and patterns of economic migration across the entire population have contributed to a venting process that limits the potential manpower available for internal violent agendas. Yet this same venting process presents some individuals avenues for jihadi mobilization, strengthening the recruitment possibilities for offshore jihadi organizations
Knowledge, management and intelligent decision support for protection scheme design and application in electrical power systems
The paper describes a research project carried out inconjunction with two major UK utilities, focusing on the introduction of knowledge management and intelligent decision support to the existing protection design and application processes operated within both companies. A brief overview is provided of the generic design process, and the development of the web-based Design Engineering Knowledge Application System (DEKAS). This system incorporates intelligent case based reasoning (CBR) functionality to address the knowledge management and decision support requirements of each company's design process. The perceived key benefits of DEKAS relating to the management and utilisation of the data, information and knowledge throughout the protection design process is also discussed
Venous thromboembolism related to cytomegalovirus infection: A case report and literature review
- …