555 research outputs found
Influencia de asfaltenos y resinas en la viscosidad de petróleos bituminosos utilizables como pinturas asfálticas de imprimación
Los crudos extrapesados procedentes del área Machete (Venezuela)
son materiales de consistencia blanda o fluida, por lo
que se salen del campo en el que normalmente se aplica el
ensayo de penetración a productos asfálticos según el mé-
todo ASTM D-5 (1), cuyo límite máximo es 30 mm, y pueden ser
utilizados como pinturas asfálticas de imprimación. Al igual que
otros productos asfálticos, estos petróleos son químicamente
una mezcla de numerosos hidrocarburos nafténicos, parafínicos,
aromáticos y compuestos heterocíclicos que contienen azufre,
nitrógeno, oxígeno, etc. Están compuestos por una fase pesada
y otra de aceites malténicos que, además de los hidrocarburos
naturales empleados como aditivos, actúa a modo de fluidificante
volátil. La primera fase se describe como una mezcla de asfalten~
o susta,ncias complejas de alto peso molecular, insoluble en hidrocarburos
parañnicos y soluble en compuestos aromáticos como
el benceno; la segunda es descrita como una mezcla de resinas
y otros hidrocarburos. Estas dos fases constituyen un sistema
coloidal. En este trabajo se presentan los resultados experimentales
del efecto de la proporción de asfaltenos y resinas en la
viscosidad de tales crudos, con vista a su aplicación como materiales
imprimadores. Los experimentos se realizaron en un reactor
batch marca Parr en una atmósfera de nitrógeno yempleando
n-heptano como disolvente. Una vez precipitados los asfaltenos
a partir de las muestras utilizadas y, seguidamente, de la fracción
de maltenos obtenida, se separaron las resinas. Al comparar
los resultados obtenidos, se encontró que los asfaltenos eran
responsables de las características estructurales y de consistencia
del vehículo, mientras las resinas le proporcionan propiedades
aglutinantes y los aceites malténicos actúan como disolventesThe bituminous crude from the Machete/ Venezuela/ area/ which
has such a fluid consistency thatitfalls outside the normalscope
of the A5TM o-s (1) penetration tes~ exceeding the 3D-mm
ceiling specified in that standar~ and can be used as an
asphaltprimer: Like other asphaltproducts/ these materials are
-chemically speaking- a mix ofnumerous naphtheni~ paraffinic
and aromatic hydrocarbons and heterocyc/ic compounds
containing sulphur, nitrogen/ oxygen and so on. They have a
dense and a malthene Ol'l phase which/ along with the natural
hydrocarbons additives usedin these products/ acts as a volatile
fluidizer: The former is described as a mix of asphaltenes:
comple~ high mo/ecular weight substances that are insolub/e in
paraffinichydrocarbons andsoluble in aromatic compounds such
as benzene. The malthene oilphase/ in turn/ consists in a mix of
resins and hydrocarbons and together the two constitute a
colloida/system. The experiments discussedin thepresentpaper
were conducted to determine the effect of the proportion of
asphaltenes and resin oils on the viscosity ofsuch bituminous
crude emulsions/ with a view to their use as primers. These
experiments were run in a Parr batch reactor in a nitrogen
atmosphere using n-heptane as a solvent. The resins were
separated after the asphaltenes precipitated from the samples
and subsequently from the malthene fraction obtained. The
results showed that the asphaltenes account for the structural
characteristics and consistency ofthe medium and the resin oils
for its cohesive properties/ the malthene oils act as solvent
EPIC-PHASE: a model to explore irrigation strategies
bstract
The erosion productivity impact calculator phase (EPIC-PHASE) model has been used to simulate, using 1972 to 1994 climatic date, two irrigation strategies with a non-limited water supply: (1) a standard strategy based on simple decision rules advisable for moderately deep soils of the Lauragais region (France) and in the Alentejo region (Portugal); and (2) a model strategy based on the daily development of soil water depletion and daily water stress intensity predicted by the model. At Lauragais, the results show that for the same level of yield it would have been possible with the model to save 73 mm on average, equivalent of two irrigations per year, compared to the standard strategy. These savings are due to an increased soil water contribution during the cycle and to an earlier end of the irrigation supply. At Alentejo, the results show that for the same level of yield as obtained with the standard strategy, it would have been possible with EPIC-PHASE model to save 100 mm of water on average, equivalent of two irrigations per year due to an increased use of soil water during the cycle. Although the results are from simulations it is proved that the standard strategy is inadequate. Regarding the environmental impact, the model management allows for an increase in the level of water depletion at harvest, delaying the risk of percolation and nitrogen losses during the refill period. The EPIC-PHASE model proved to be a tool capable of defining an irrigation schedule better adapted to the Mediterranean region
Multivariate Base Rates of Low Score on Neuropsychological Tests of Individuals with Coca Paste Use Disorder
Objective
The aim of this study was to determine the prevalence of low scores on eight commonly used neuropsychological tests to evaluate learning and memory, language, and executive functions in individuals with coca paste use disorders (CPUD) and to identify the differences with respect to a group of healthy nonconsuming subjects (HCs).
Methods
162 Colombian adults with CPUD and a group of 162 Colombian adult HCs participated in this comparative study. Eight tests (eighteen test scores) were grouped into three categories: learning and memory, language, and executive functions. Each participant was categorized based on the number of low scoring tests in specific percentile cut-off groups (25th, 16th, 10th, 5th, and 2nd).
Results
In the learning and memory domain, 89.5% of individuals with CPUD and 55.6% of HCs scored below the 25th percentile on at least one of the five test scores, in the language domain, 80.7% of individuals with CPUD and 58% of HCs and in the executive function domain, 92% of individuals with CPUD and 67.3% of HCs. Having two or more scores below the 10th percentile or 10 or more at the 5th percentile shows an optimal cut-off for determining the sensitivity and specificity for discriminating between the two groups.
Conclusions
The individuals with CPUD had a higher percentage of low scores than the HCs in the domains of learning and memory, language, and executive function. It is important for clinicians to be aware of low scores in individuals with CPUD to avoid false-positive diagnoses of cognitive impairment
New insights from U–Pb zircon dating of Early Ordovician magmatism on
The Central Iberian–Ossa-Morena transition zone (SW Iberian Massif) represents a segment of the northern Gondwana margin with a long
geodynamic evolution, characterized by the superposition of Cadomian and Variscan events. The Early Ordovician is mainly represented by
porphyritic felsic volcaniclastic rocks (the Urra Formation) that pass up into a siliciclastic sediments typical of the Central Iberian Zone (Lower
Ordovician Armorican Quartzite Formation). The Urra Formation unconformably overlies the previously deformed and metamorphosed Ediacaran
sediments of the Série Negra (with Ossa-Morena Zone paleogeographic affinity). New SHRIMP zircon data obtained from the Urra Formation
volcaniclastic rocks indicate an Early Ordovician age (206Pb/238U ages ranging from 494.6±6.8 Ma to 488.3±5.2 Ma) for this magmatic event.
The inherited zircon cores indicate the presence of multicycle protoliths with different Precambrian ages: Neoproterozoic (698–577 Ma),
Paleoproterozoic (2.33 Ga) and Paleoarchean (3.2–3.3 Ga). There is a noticeable lack of Meso- to Neoarchean and Mesoproterozoic ages. The
data support the hypothesis that the volcaniclastic rocks were derived by partial melting of Cadomian basement (linked to a West African Craton
provenance). The Urra Formation volcaniclastic rocks have rhyolitic to dacitic compositions, are peraluminous and similar to calc-alkaline high-K
series suites elsewhere. Isotopic signatures present a wide range of values (87Sr/86Sr)t=0.7085–0.7190, more restricted εNdt (−2.65 to −0.35) and
δ18O=9.63–10.34‰, compatible with magmas derived from crustal rocks, including portions of the lower crust. Some samples show disturbance
of the Rb–Sr system as shown by unrealistic values for (87Sr/86Sr)tb0.703, probably due to Variscan deformation and metamorphism. The
volcaniclastic rocks with a significant sedimentary contribution (upper unit) are distinguished from the others by the lowest values of εNdt (−5.53
to −4.85). The geochemical data are compatible with an orogenic geodynamic environment. However, the “orogenic” signature can be considered
to represent, in part, an inherited feature caused by melting of the Cadomian basement which also has calc-alkaline affinities. The Early
Ordovician crustal growth and associated magmatism, represented by the Urra felsic volcaniclastic rocks and associated calc-alkaline granitoids,
diorites and gabbros, can be interpreted in terms of the underplating and temporal storage of mantle-derived magmas as the potential source for the
“orogenic melts” that were intruded during Early Paleozoic extension. This record of Early Ordovician magmatism has striking similarities with
other correlatives from the Iberian, Bohemian and Armorican massifs that are discussed in this paper. This comparison reinforces the probable
existence of a large-scale crustal melting process linked to a significant episode of extension on the northern Gondwana margin that probably
resulted in the birth of the Rheic Ocean
Does Functionality Condition the Population Structure and Genetic Diversity of Endangered Dog Breeds under Island Territorial Isolation?
Despite the undefinition of the origins of Ca de Rater (CR) and Ca de Bestiar (CB) dogs, references to these endangered autochthonous breeds highlighted their ratting/pet and shepherding/guard skills for centuries. Genealogical historical records were traced back to founders. Founder number in the reference population (146 and 53 for CR and CB, respectively), historical and reference maximum generations traced (eight and seven for CR and CB, respectively), and historical average number of complete generations (1.04 for both breeds) were determined. Structure assessment revealed the existence of subpopulations regarding criteria such as breeders (75 and 17), breeder location (32 and eight), owners (368 and 198), and owner location (73 and 51) for CR and CB, respectively. Average inbreeding (F) within breed subpopulations ranged from 0.27–1.20% for CB breeders and the rest of subpopulation criteria for both breeds, respectively, except for CB owners and owner location. F ranged from 0.27–1.41% for CB historical population and CR current population, respectively. The study of genetic diversity revealed a relatively similar genetic background between subpopulations. Average coancestry between and within breeds suggested a similar evolutionary process. However, Mann–Whitney U test determined significant differences for diversity parameters (F, ΔR, coancestry, nonrandom mating degree, maximum, complete, and equivalent generations, ΔF, and genetic conservation index) between breeds and their functionalities. Conclusively, functionality in dog breeds may determine the genetic diversity evolution of endangered breeds, even when these share the same geographic isolation conditions
Leptospirosis in Campinas, São Paulo, Brazil : 2007-2014
Analisar a distribuição de casos e óbitos humanos por leptospirose, segundo características sociodemográficas, epidemiológicas, clínicas, tempo de atendimento, pluviosidade e distribuição espacial em Campinas, São Paulo, no período de 2007 a 2014. Estudo ecológico utilizando informações dos casos confirmados de leptospirose. Realizou-se análise descritiva dos casos, segundo variáveis selecionadas. A relação entre casos autóctones e pluviosidade foi verificada pelo coeficiente de correlação de Spearman. Georreferenciaram-se casos/óbitos por áreas classificadas segundo indicadores socioambientais. Dos 264 casos, 76,1% eram homens e 58,4% tinham entre 20 e 49 anos. Cerca de 55% foram hospitalizados. Prevaleceu o diagnóstico clínico-laboratorial (89,4%) e a letalidade foi de 10,6%. Na área urbana, ocorreram 74,2% dos casos e, 48,9%, no domicílio. O principal fator de risco foi o local com sinal de roedores. Houve forte correlação entre a incidência de casos e a pluviosidade (p < 0,05) nos anos de 2010 a 2012. Observou-se maior concentração de casos na região centro-sudoeste. A distribuição espacial dos casos/óbitos mostrou aglomerados em regiões classificadas como de menor nível socioeconômico. Os padrões de ocorrência de leptospirose em Campinas, São Paulo, mostraram similaridade com outras cidades brasileiras. A identificação de áreas com maior incidência de casos/óbitos contribui para a adoção de estratégias específicas de intervenção e priorização de recursos na redução do risco de infecção e tratamento precoce dos acometidos pela doença22To analyze the distribution of leptospirosis according to sociodemographic, epidemiologic, and clinical characteristics, assistance time, rainfall and spatial distribution in Campinas/SP in the period from 2007 to 2014. This is an ecological study using information from the confirmed cases. A descriptive analysis was carried out according to the selected variables. The relationship between the cases and rainfall was verified through the Spearman’s correlation coefficient. The cases/deaths were georeferenced per areas classified according to socioenvironmental deprivation indexes in Campinas. From the 264 cases, 76.1% occurred in men, 58,4% in the 20 to 49 years old age range. Approximately 55% were hospitalized, with a prevalence of clinical-laboratorial diagnoses of 89.4%, and the lethality was 10.6%. The urban area concentrated 74.2% of the cases, and 48,9% occurred in the household environment. The main risk factor was evidence of the presence of rodents at the site. There was strong correlation between the incidence of cases and rainfall (p < 0.05) in 2010 to 2012. A higher concentration of the cases was observed in the Center-Southwest region. Spatial distribution of cases/deaths showed clusters in regions classified at lower socioeconomic levels. The patterns of occurrence of leptospirosis in Campinas showed similarity with other Brazilian municipalities. The identification of areas with higher incidence of cases/deaths contributes to the adoption of strategies for intervention and prioritization of resources aiming at the reduction of the risk of infection and at early treatment for those affecte
Automatic Inference of Determinacy and Mutual Exclusion for Logic Programs Using Mode and Type Analyses
We propose an analysis for detecting procedures and goals
that are deterministic (i.e., that produce at most one solution at most once),or predicates whose clause tests are mutually exclusive (which implies that at most one of their clauses will succeed) even if they are not deterministic.
The analysis takes advantage of the pruning operator in order to improve the detection of mutual exclusion and determinacy. It also supports arithmetic equations and disequations, as well as equations and disequations on terms,for which we give a complete satisfiability testing algorithm, w.r.t. available type information. Information about determinacy can be used for program debugging and optimization, resource consumption and granularity control,
abstraction carrying code, etc. We have implemented the analysis and integrated it in the CiaoPP system, which also infers automatically the mode and type information that our analysis takes as input. Experiments performed on this implementation show that the analysis is fairly accurate and efficient
The Cardiology Audit and Registration Data Standards (CARDS), European data standards for clinical cardiology practice
AIMS: Systematic registration of data from clinical practice is important for clinical care, local, national and international registries, and audit. Data to be collected for these different purposes should be harmonized. Therefore, during Ireland's Presidency of the European Union (EU) (January to June 2004), the Department of Health and Children worked with the European Society of Cardiology, the Irish Cardiac Society, and the European Commission to develop data standards for clinical cardiology. The Cardiology Audit and Registration Data Standards (CARDS) Project aimed to agree standards for three modules of cardiovascular health information systems: acute coronary syndromes (ACS), percutaneous coronary interventions (PCI), and clinical electrophysiology (pacemakers, implantable cardioverter defibrillators, and ablation procedures). METHODS AND RESULTS: Data items from existing registries and surveys were reviewed to derive draft data standards (variables, coding, and definitions). Variables common to the three modules include demographics, risk factors, medication, and discharge and follow-up data. Modules about a procedure contain variables on the l
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