402 research outputs found
Comparison of Braking Performance for Different Technologies of Heavy Hauled Freight Trains
The paper shows a comparison of different braking technologies for freight trains
and their effects on in-train forces. At this aim, the UIC certified software TrainDy
is employed. Freight train sets, having one and two remote locomotives, are
investigated both as coupled trains and as fixed train compositions. There is also an
evaluation of the in-train forces of freight train sets equipped by electro-pneumatic
brakes and disk brakes. The case of two remote locomotives is further explored
showing the minor benefits of an ad hoc activation of drivers brake valve, compared
to the benefits of an optimized mass distribution, for train sets both coupled and
fixed
The Train dynamics of wheel rail contact and longitudinal lateral interaction between vehicles
This paper is focused on the vehicle dynamics caused by the forces exchanged,
through buffers and draw gears, by consecutive vehicles on a curve. The results have
been obtained by adding a buffers/draw gears contact model on an existing
multibody code, previously developed by the authors. The multibody code manages
rigid bodies connected by elastic and rigid constraints; the wheel/rail contact model
is three dimensional and employs an elastic constraint among wheel and rail. The
wheel/rail contact is managed by means of a numerical model called TOAM (third
order approximation method). Numerical tests and experimental validations of the
proposed model are here presented, considering a train made by three vehicles,
running on an S shaped curve, subjected to parametric compressive forces
Decidability results for classes of purely universal formulae and quantifiers elimination in Set Theory
A general mechanism to extend decision algorithms to deal with additional predicates is described. The only conditions imposed on the predicates is stability with respect to some transitive relations
Effetto delle azioni dinamiche tra organi di trazione e repulsione sull’interazione ruota-rotaia di carri merci a due assi
Translocação do inseticida tiametoxam+lambdacialotrina da folha para a haste de plantas de soja.
Foram realizados dois experimentos com objetivo de avaliar a translocação do inseticida tiametoxam+lambdacialotrina da folha para a haste da planta de soja, utilizando o percevejo Edessa meditabunda como bioindicador. Em casa-de-vegetação, plantas de soja da cultivar BRS 284, no estágio R5, foram tratadas com 1,667 mL/L de Engeo Pleno® (tiametoxam+lambdacialotrina), pelo método de imersão da folha. Foi utilizado o delineamento inteiramente casualizado, com unidades experimentais compostas por 3 adultos do percevejo confinados na haste da planta de soja. No EXPERIMENTO A foram estudados 4 tratamentos com 4 repetições. Nos tratamentos T1A e T2A todas as folhas foram tratadas com o inseticida e a haste foi infestada na sua metade superior e inferior, respectivamente. T3A e T4A não receberam inseticida e a haste foi infestada na sua metade superior e inferior, respectivamente. Os resultados mostram que ocorre translocação do inseticida da folha para a haste, em quantidade suficiente para causar mortalidade superior a 93% (T1A) e 83% (T2A), aos 9-12 DAI (dias após a infestação). No EXPERIMENTO B foram estudados 6 tratamentos com 6 repetições. Em T1B e T2B foram tratadas as folhas da metade superior da planta e foi infestada a haste da sua metade superior e inferior, respectivamente. Em T3B e T4B foram tratadas as folhas da metade inferior da planta e foi infestada a sua metade superior e inferior, respectivamente. T5B e T6B não receberam inseticida e a planta foi infestada na sua metade superior e inferior, respectivamente. Neste experimento, as maiores mortalidades foram observadas aos 10 DAI, nos tratamentos em que os insetos foram confinados na mesma metade da planta que recebeu o inseticida, T1B (77%) e T4B (70%) não diferindo de T3B (63%) em que os insetos foram confinados acima do ponto de aplicação do inseticida. Enquanto que em T2B a mortalidade foi inferior a 17%. Assim conclui-se que o produto transloca da folha para a haste e apresenta movimento ascendente
Efeito sistêmico de inseticida (tiametoxam+ lambda-cialotrina) em planta de soja.
O trabalho teve por objetivo avaliar o efeito sistêmico do inseticida tiametoxam+lambda-cialotrina em plantas de soja. Foi realizado um experimento emR4 e outro em R5.3,com delineamento inteiramente casualizado,6tratamentos e 5repetições, sendo cada repetição constituída por 3adultos de E. heros e um vaso com planta de soja. Os tratamentos foram compostos pela combinação de 2locais de pulverização detiametoxam+lambda-cialotrina (Engeo Pleno)(metade superior e metade inferior da planta)e 2locais de infestação com percevejos (metade superior e metade inferior da planta): T1 -aplicação e infestação superior; T2 - aplicação superior e infestação inferior; T3 - aplicação inferior e infestação superior; T4 - aplicação e infestação inferior; T5 -sem aplicação e infestação superior; T6 - sem aplicação e infestação inferior. Avaliação da mortalidade dos insetos foi realizada aos 1, 4, 8 e 11 dias após a infestação (DAI). Nos dois estádios avaliados (R4 e R5.3) houve mortalidade dos insetos da metade superior de plantas que receberam o inseticida na metade inferior (T3), indicando que há efeito sistêmico ascendente. A partir de 8 DAI a mortalidade do tratamento T3 não diferiu daqueles em que houve exposição direta (T1 e T4), nos quais foi observada a maior mortalidade de insetos. Já para o tratamento (T2) em que os insetos foram confinados na metade inferior de plantas pulverizadas na sua metade superior a mortalidade não diferiu das testemunhas, indicando não haver efeito sistêmico descendente para o produto estudado
QuickXsort: Efficient Sorting with n log n - 1.399n +o(n) Comparisons on Average
In this paper we generalize the idea of QuickHeapsort leading to the notion
of QuickXsort. Given some external sorting algorithm X, QuickXsort yields an
internal sorting algorithm if X satisfies certain natural conditions.
With QuickWeakHeapsort and QuickMergesort we present two examples for the
QuickXsort-construction. Both are efficient algorithms that incur approximately
n log n - 1.26n +o(n) comparisons on the average. A worst case of n log n +
O(n) comparisons can be achieved without significantly affecting the average
case.
Furthermore, we describe an implementation of MergeInsertion for small n.
Taking MergeInsertion as a base case for QuickMergesort, we establish a
worst-case efficient sorting algorithm calling for n log n - 1.3999n + o(n)
comparisons on average. QuickMergesort with constant size base cases shows the
best performance on practical inputs: when sorting integers it is slower by
only 15% to STL-Introsort
Molecular mechanism of tanshinone IIA and cryptotanshinone in platelet anti-aggregating effects: an integrated study of pharmacology and computational analysis.
Tanshinone IIA and cryptotanshinone are two pharmacologically active diterpenoids extracted from the roots of Salvia milthiorriza Bunge, a plant used in Chinese traditional medicine for the treatment of some cardiovascular and cerebrovascular disease. Until now, the molecular mechanisms of action of these two diterpenoids on platelets are partially known. To clarify this aspect, here we utilized an integrated study of pharmacology and computational analysis. Our results demonstrate that cryptotanshinone is able to inhibit in a concentration dependent manner the rat platelet aggregation and also is endowed of Gi-coupled P2Y12 receptor antagonist as demonstrated by docking studies. This computational method was also performed for tanshinone IIA demonstrating even for this diterpenoid an interaction with the same receptor. The findings from our study enable a better understanding of tanshinone IIA and cryptotanshinone biological properties, which could ultimately lead to the development of novel pharmaceutical strategies for the treatment and/or prevention of some cardiovascular disease
Particulate Air Pollution, Clock Gene Methylation, and Stroke : Effects on Stroke Severity and Disability
Circadian rhythm disturbances have been consistently associated with the development of several diseases, particularly cardiovascular diseases (CVDs). A central clock in the brain maintains the daily rhythm in accordance with the external environment. At the molecular level, the clock is maintained by \u201cclock genes\u201d, the regulation of which is mainly due to DNA methylation, a molecular mechanism of gene expression regulation, able to react to and be reprogrammed by environmental exposure such as exposure to particulate matter (PM). In 55 patients with a diagnosis of acute ischemic stroke, we showed that PM2.5 exposure experienced before the event influenced clock genes methylation (i.e., circadian locomotor output cycles protein kaput CLOCK, period 2 PER2, cryprochrome 1 CRY1, Neuronal PAS Domain Protein 2 NPAS2), possibly modulating the patient prognosis after the event, as cryptochrome 1 CRY1 and period 1 PER1 methylation levels were associated with the Rankin score. Moreover, if PM2.5 annual average was low, CRY1/CRY2 methylation levels were positively associated with the National Institutes of Health Stroke Scale (NIHSS) score, whereas they were negatively associated if PM2.5 exposure was high. Whether epigenetic changes in clock genes need to be considered as a prognostic marker of stroke or rather a causal agent in stroke development remains to be determined. Further studies are needed to determine the role of clock gene methylation in regulating the response to and recovery after a stroke event
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