773 research outputs found
Beyond the High Ground: A Taxonomy for Earth-Moon System Operations
Situational and space domain awareness in the space domain can no longer be confined to that which is found in geosynchronous orbit. International activities—commercial and military—and threats to the planet itself exist and are increasing across the entire Earth-Moon system. This reality requires a new taxonomy to accurately classify space domain awareness missions and better apply resources to and development of the same. This work presents such a taxonomy for the classification of space domain awareness regions
Suspension systems for ground testing large space structures
A research program is documented for the development of improved suspension techniques for ground vibration testing of large, flexible space structures. The suspension system must support the weight of the structure and simultaneously allow simulation of the unconstrained rigid-body movement as in the space environment. Exploratory analytical and experimental studies were conducted for suspension systems designed to provide minimum vertical, horizontal, and rotational degrees of freedom. The effects of active feedback control added to the passive system were also investigated. An experimental suspension apparatus was designed, fabricated, and tested. This test apparatus included a zero spring rate mechanism (ZSRM) designed to support a range of weights from 50 to 300 lbs and provide vertical suspension mode frequencies less than 0.1 Hz. The lateral suspension consisted of a pendulum suspended from a moving cart (linear bearing) which served to increase the effective length of the pendulum. The torsion suspension concept involved dual pendulum cables attached from above to a pivoting support (bicycle wheel). A simple test structure having variable weight and stiffness characteristics was used to simulate the vibration characteristics of a large space structure. The suspension hardware for the individual degrees of freedom was analyzed and tested separately and then combined to achieve a 3 degree of freedom suspension system. Results from the exploratory studies should provide useful guidelines for the development of future suspension systems for ground vibration testing of large space structures
An investigation into the fertilizer potential of slaughterhouse cattle paunch
In Australia, the red meat processing industry actively seeks approaches to improve the management of solid waste from processing operations and enhance the environmental performance. Recycling of paunch waste to farmland could be a cost-effective and practicable environmental option. However, little is known about the agronomic value of fresh and composted paunch, and the associated requirements for land application. Therefore, a short-term experimental work was undertaken to assess potential risks due to weed seed contamination and determine the agronomic response of ryegrass (Lolium perenne L.) to soil incorporation of paunch. The risk of weed contamination from soil application of paunch appeared to be low; however, methods that account for viability of seeds may be required to fully discard such a risk. Soil application of paunch at field equivalent rates of 150-300 kg ha-1 of N increased dry matter yield by ≈30% on average compared with untreated grass, but was approximately 35% lower than a mineral fertilizer treatment applied at the same rates. Dry matter yield of paunch-treated grass was between 2000 and 3000 kg per ha over four consecutive cuts at 25-day intervals. Nitrogen use-efficiency of paunch was approximately 10% (range: 3% to 20%, depending on paunch type), and total N in harvested plant material showed values, which were between 2% and 3%. Overall, there appears to be potential for paunch-derived products to be used as a source of carbon and nutrients in crop production. Areas that merit a research priority within this space are also outlined in this paper. Such work is required to inform soil-, climate- and crop-specific land application rates, optimize agronomic performance, and minimize environmental concerns. There is also a requirement for the value proposition to industry to be determined, including reduced cost of disposal of material via gate fees and fertilizer replacement value
A Bi-Directional Refinement Algorithm for the Calculus of (Co)Inductive Constructions
The paper describes the refinement algorithm for the Calculus of
(Co)Inductive Constructions (CIC) implemented in the interactive theorem prover
Matita. The refinement algorithm is in charge of giving a meaning to the terms,
types and proof terms directly written by the user or generated by using
tactics, decision procedures or general automation. The terms are written in an
"external syntax" meant to be user friendly that allows omission of
information, untyped binders and a certain liberal use of user defined
sub-typing. The refiner modifies the terms to obtain related well typed terms
in the internal syntax understood by the kernel of the ITP. In particular, it
acts as a type inference algorithm when all the binders are untyped. The
proposed algorithm is bi-directional: given a term in external syntax and a
type expected for the term, it propagates as much typing information as
possible towards the leaves of the term. Traditional mono-directional
algorithms, instead, proceed in a bottom-up way by inferring the type of a
sub-term and comparing (unifying) it with the type expected by its context only
at the end. We propose some novel bi-directional rules for CIC that are
particularly effective. Among the benefits of bi-directionality we have better
error message reporting and better inference of dependent types. Moreover,
thanks to bi-directionality, the coercion system for sub-typing is more
effective and type inference generates simpler unification problems that are
more likely to be solved by the inherently incomplete higher order unification
algorithms implemented. Finally we introduce in the external syntax the notion
of vector of placeholders that enables to omit at once an arbitrary number of
arguments. Vectors of placeholders allow a trivial implementation of implicit
arguments and greatly simplify the implementation of primitive and simple
tactics
DETERMINANTS OF ENERGY CONSUMPTION: A REVIEW OF THE PHILIPPINE ENERGY SECTOR
Energy is considered a vital component of economic growth and human development. When its availability is disrupted, several economic sectors could not function fully to its extent. Energy consumption is influenced by several variables that affect it directly or indirectly. This study was conducted to evaluate the impact of GDP, industrialization, urbanization, trade openness, financial development, and FDI on the energy consumption of the Philippines; and to present the trend of each variable from 1971 to 2014. Data on energy consumption, GDP, industrialization, urbanization, trade openness, financial development, and FDI of the Philippines from 1971 to 2014 were sourced from the World Development Indicators published by the World Bank. The Ordinary Least Squares (OLS) regression analysis was used to analyze and identify those factors that significantly affect the energy consumption of the Philippines. Results indicated that GDP, industrialization, urbanization, and financial development significantly affect the energy consumption of the Philippines. These determinants have p-values that are lower than the 5% significance level. Thus, this study provides the policy and decision-makers with ample information for decisive decision-making in the Philippine energy sector. Article visualizations
Modelo espacial con acercamiento Bayesiano para el estudio de vÃctimas en Colombia 2015.
Colombia se encuentra en una coyuntura vital para las nuevas generaciones, que consiste en una paz sostenible y duradera, dada la firma del acuerdo de paz con las FARC. En efecto, la importancia de dicha coyuntura recae en las vÃctimas y en identificar factores influyentes en la cantidad de éstas en los municipios de Colombia. En este artÃculo se propone modelar el comportamiento de la cantidad de vÃctimas para el año 2015 a través de un modelo CAR con respuesta Poisson y la estimación se hizo de forma bayesiana. Con la aplicación del modelo en mención, se identificaron factores que influencian el aumento de la cantidad de vÃctimas, lo que permitirÃa la implementación de polÃticas públicas que minimicen el riesgo de victimización. Estos resultados abren la posible que en futuras investigaciones se identifiquen factores de incidencia adicionales, con el fin de contribuyen a la reparación de las vÃctimas en el proceso de posconflicto.
respuesta Poisson y la estimación se hizo de forma bayesiana. Con la aplicación del modelo en mención, se identifi caron
factores que infl uencian el aumento de la cantidad de vÃctimas, lo que permitirÃa la implementación de polÃticas públicas
que minimicen el riesgo de victimización. Estos resultados abren la posible que en futuras investigaciones se identifi quen
factores de incidencia adicionales, con el fi n de contribuyen a la reparación de las vÃctimas en el proceso de posconfl icto
Analysis of CTNS gene transcripts in nephropathic cystinosis
Nephropathic cystinosis (NC) is an autosomal recessive disorder caused by mutations of the CTNS gene that encodes for a cystine transmembrane transporter. Several mutations have been described in the coding and promoter regions of the CTNS gene in affected individuals. We selected three patients with NC from two unrelated families, in whom sequence analysis of the CTNS gene detected only one or no mutations. Total RNA was isolated from peripheral blood mononuclear cells or fibroblasts and CTNS transcripts were analyzed. We observed a skipping of exon 5 (85 bp) in two siblings and an intron 9 retention of 75 bp associated with partial replication of exon 9 in the third patient. Genomic DNA analysis of intron regions surrounding exon 5 showed a point mutation in the hypothetical lariat branch site of intron 4 at position –24 (c.141–24 T > C) in the first two patients and a duplication of 266 bp including a part of exon and intron 9 in the third patient. Analysis of CTNS gene transcripts allowed identification of mutations in patients in whom CTNS mutations could not be detected by traditional DNA sequencing. These results support the hypothesis that cystinosis is a monogenic disorder
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