Intermediate Situation Research Articles

Assessing the pattern of covariance matrices via an augmentation multiple testing procedure

This paper extends the scedasticity comparison among several groups of observations, usually complying with the homoscedastic and the heteroscedastic cases, in order to deal with data sets laying in an intermediate situation. As is well known, homoscedasticity corresponds to equality in orientation, shape and size of the group scatters. Here our attention is focused on two weaker requirements: scatters with the same orientation, but with different shape and size, or scatters with the same shape and size but different orientation. We introduce a multiple testing procedure that takes into account each of the above conditions. This approach discloses a richer information on the data underlying structure than the classical method only based on homo/heteroscedasticity. At the same time, it allows a more parsimonious parametrization, whenever the patterned model is appropriate to describe the real data. The new inferential methodology is then applied to some well-known data sets, chosen in the multivariate literature, to show the real gain in using this more informative approach. Finally, a wide simulation study illustrates and compares the performance of the proposal using data sets with gradual departure from homoscedasticity.

Dynamic adaptation of response-time models for QoS management in autonomic systems

In transactional systems, the objectives of quality of service regarding are often specified by Service Level Objectives (SLOs) that stipulate a response time to be achieved for a percentile of the transactions. Usually, there are different client classes with different SLOs. In this paper, we extend a technique that enforces the fulfilment of the SLOs using admission control. The admission control of new user sessions is based on a response-time model. The technique proposed in this paper dynamically adapts the model to changes in workload characteristics and system configuration, so that the system can work autonomically, without human intervention. The technique requires no knowledge about the internals of the system; thus, it is easy to use and can be applied to many systems. Its utility is demonstrated by a set of experiments on a system that implements the TPC-App benchmark. The experiments show that the model adaptation works correctly in very different situations that include large and small changes in response times, increasing and decreasing response times, and different patterns of workload injection. In all this scenarios, the technique updates the model progressively until it adjusts to the new situation and in intermediate situations the model never experiences abnormal behaviour that could lead to a failure in the admission control component.

Analysis of investments in generation capacity: a bilevel approach

This paper introduces a bilevel model that represents the behaviour of a firm which, faced with the need to build new plants, has to choose between a number of alternative technologies. The main contribution of the model is that the market representation (lower level) is made using a conjectured-price-variation approach. This formulation is able to represent different degrees of oligopoly in the market, which is a more realistic hypothesis than the perfect competition or Cournot oligopoly considerations. In the objective function of the upper level, the firm's net present value is maximised, considering that the company is in an incumbent position and knows the new capacity that will be built by the others. A study case is analysed to show the outputs corresponding to four different market behaviours: perfect competition, two intermediate oligopolistic market situations represented by different values for the conjectured variations and Cournot oligopoly as an extreme oligopolistic situation. The results show that if a company is taken to be the only investing company at the investment level, the higher the degree of oligopoly in the market, the greater the investment and the greater the use of peak technologies.

Microscopic description of large-amplitude shape-mixing dynamics with inertial functions derived in local quasiparticle random-phase approximation

On the basis of the adiabatic self-consistent collective coordinate method, we develop an efficient microscopic method of deriving the five-dimensional quadrupole collective Hamiltonian and illustrate its usefulness by applying it to the oblate-prolate shape coexistence/mixing phenomena in proton-rich $^{68,70,72}\mathrm{Se}$. In this method, the vibrational and rotational collective masses (inertial functions) are determined by local normal modes built on constrained Hartree-Fock-Bogoliubov states. Numerical calculations are carried out using the pairing-plus-quadrupole Hamiltonian including the quadrupole-pairing interaction within the two major-shell active model spaces both for neutrons and protons. It is shown that the time-odd components of the moving mean-field significantly increase the vibrational and rotational collective masses in comparison with the Inglis-Belyaev cranking masses. Solving the collective Schr\"odinger equation, we evaluate excitation spectra, quadrupole transitions, and moments. The results of the numerical calculation are in excellent agreement with recent experimental data and indicate that the low-lying states of these nuclei are characterized as an intermediate situation between the oblate-prolate shape coexistence and the so-called $\ensuremath{\gamma}$ unstable situation where large-amplitude triaxial-shape fluctuations play a dominant role.

Trace fossils of a cyclic chalk–marl succession; the upper Maastrichtian Rørdal Member, Denmark

Trace fossils from an upper Maastrichtian cyclic chalk–marl succession, the Rørdal Member, exposed in the Rørdal quarry, Denmark, are analysed in order to test whether the changes in substrate lithology exerted any control over the ichnodiversity, tiering complexity, and density of the infauna. The cyclicity is interpreted as caused by orbital changes within the Milankovitch frequency band. The carbonate content varies between 71 and 82 weight% in the marl and 82–92 weight% in the chalk beds. The material is based on 19 samples collected from six chalk and marl beds. The investigated bedding-normal sample surfaces vary in area between 29 and 155cm2. Eight ichnogenera and two undetermined ichnogenera are recognised. The member is characterised by three ichnofabrics (A, B and C). The ichnofabric analysis is based on texture and internal structure of the sediments resulting from bioturbation. Ichnofabric A is found only in chalk samples and shows a poor preservation of trace fossils, whereas ichnofabric C is found in a few chalk and all marl samples and comprises a very dense, diverse and well preserved ichnofauna representing a high tiering complexity. Ichnofabric B represents an intermediate situation between ichnofabrics A and C and occurs in chalk samples immediately adjacent to marl beds. The observed changes in ichnofabrics between chalk and marl are related to the amount of clay in the samples and the differences in the occurrence of trace fossils are interpreted as due to differences in the visibility of traces between chalk and marl and not due to differences in ecological stress upon the endobenthic community of the two lithologies. The study thus provides an excellent example of how the effect of taphonomic factors may give a misleading and biased impression of apparent differences in the endobenthic community between chalk and marl.

Impact of land degradation on soil respiration in a steppe (Stipa tenacissima L.) semi-arid ecosystem in the SE of Spain

Climate change scenarios predict increases in temperature, changes in precipitation patterns, and longer drought periods in most semi-arid regions of the world. Ecosystems in these regions are prone to land degradation, which may be aggravated by climate change. Soil respiration is one of the main processes responsible for organic carbon losses from arid and semi-arid ecosystems. We measured soil respiration over one year in two steppe ecosystems having different degrees of land degradation under three ground-covers: with vegetation, bare soil, and an intermediate situation between plants and bare soil. The largest differences in soil respiration rates between the sites were observed in spring, coinciding with the highest level of plant activity. The degraded site had drier and hotter soils with less soil water availability and a longer drought period. As a result, vegetation on the degraded site did not respond to spring rainfall events. Soil respiration showed a strong seasonal variability, with average annual rates of 1.1 and 0.8 μmol CO 2 m −2 s −1 in the natural and degraded sites, respectively. We did not observe significant differences in soil respiration rates associated with ground-cover i.e., the temporal variation was much larger than the spatial variation. At both sites, soil moisture was the controlling driver of soil respiration for most of the year, when temperatures were above 20 °C and constrained the response to temperature for the few months when the temperature was below 20 °C. An empirical model based on soil temperature and soil moisture explained 90% and 72% of the seasonal variability of soil respiration on the natural and degraded sites, respectively. For the first time, this study suggests that land degradation may alter the carbon balance of these ecosystems through changes in the temporal dynamics of soil respiration and plant productivity, which have important negative consequences for ecosystem functioning and sustainability. ► The seasonal and spatial variation of soil respiration in a semi-arid grassland ecosystem. ► The importance of soil temperature and moisture controlling soil respiration in these regions. ► The impact of land degradation by comparing the dynamics of soil respiration in two steppe ecosystems with different degree of vegetation cover.

Assessing land-use effects on water quality, in-stream habitat, riparian ecosystems and biodiversity in Patagonian northwest streams

Changes in land-use practices have affected the integrity and quality of water resources worldwide. In Patagonia there is a strong concern about the ecological status of surface waters because these changes are rapidly occurring in the region. To test the hypothesis that greater intensity of land-use will have negative effects on water quality, stream habitat and biodiversity we assessed benthic macroinvertebrates, riparian/littoral invertebrates, fish and birds from the riparian corridor and environmental variables of 15 rivers (Patagonia) subjected to a gradient of land-use practices (non-managed native forest, managed native forest, pine plantations, pasture, urbanization). A total of 158 macroinvertebrate taxa, 105 riparian/littoral invertebrate taxa, 5 fish species, 34 bird species, and 15 aquatic plant species, were recorded considering all sites. Urban land-use produced the most significant changes in streams including physical features, conductivity, nutrients, habitat condition, riparian quality and invertebrate metrics. Pasture and managed native forest sites appeared in an intermediate situation. The highest values of fish and bird abundance and diversity were observed at disturbed sites; this might be explained by the opportunistic behavior displayed by these communities which let them take advantage of increased trophic resources in these environments. As expected, non-managed native forest sites showed the highest integrity of ecological conditions and also great biodiversity of benthic communities. Macroinvertebrate metrics that reflected good water quality were positively related to forest land cover and negatively related to urban and pasture land cover. However, by offering stream edge areas, pasture sites still supported rich communities of riparian/littoral invertebrates, increasing overall biodiversity. Macroinvertebrates were good indicators of land-use impact and water quality conditions and resulted useful tools to early alert of disturbances in streams. Fish and birds having a greater ability of dispersion and capacity to move quickly from disturbances would reflect changes at a higher scale.

Automobile shredded residue valorisation by hydrometallurgical metal recovery

The aim of this work was developing a hydrometallurgical process to recover metals from automobile shredded residue (or car fluff). Automobile shredded residue (ASR) was characterised by particle size distribution, total metal content and metal speciation in order to guide the choice of target metals and the operating conditions of leaching. Characterisation results showed that Fe is the most abundant metal in the waste, while Zn was the second abundant metal in the fraction with diameter lower than 500 μm. Sequential extractions denoted that Zn was easily extractable by weak acid attack, while Fe and Al required a strong acid attack to be removed. In order to recover zinc from <500 μm fraction leaching tests were operated using acetic acid, sulphuric acid and sodium hydroxide at different concentrations. Sulphuric acid determined the highest zinc extraction yield, while acetic acid determined the highest zinc extractive selectivity. Sodium hydroxide promoted an intermediate situation between sulphuric and acetic acid. Zn recovery by electro winning using acetic leach liquor determined 95% of Zn electro deposition yield in 1 h, while using sulphuric leach liquor 40% yield in 1 h and 50% yield in 2 h were obtained. Simulation results showed that the sulphuric leaching process was more attractive than acetic leaching process.

Proposta metodológica de cobrança pelo uso dos recursos hídricos usando o valor de Shapley: uma aplicação à bacia do rio Paraíba do Sul

Este trabalho teve como objetivo propor uma metodologia de cobrança pelo uso de recursos hídricos baseada na alocação de custos - entre os setores demandantes de água - de projetos relacionados com melhorias em uma bacia hidrográfica. Essa metodologia consiste em regra de alocação conhecida como valor de Shapley, pertencente à teoria de jogos cooperativos, e, para mostrar sua aplicabilidade, realizou-se um estudo de caso no trecho paulista da bacia do rio Paraíba do Sul, tendo-se utilizado, como critérios de alocação de custos, os volumes de água captada e consumida, além da quantidade lançada de efluentes. Na aplicação da metodologia, consideraram-se três cenários distintos: bacia "limpa", bacia poluída e uma situação intermediária, mais próxima da realidade atualmente encontrada na sub-bacia analisada. Os resultados obtidos mostraram-se altamente dependentes dos critérios de alocação de custos adotados (pesos atribuídos aos volumes de água captada e consumida e quantidade lançada de efluentes), sendo que, no caso do cenário intermediário considerado, os valores encontrados indicaram que os usuários urbanos deveriam arcar com a maior parte dos custos quando comparados às taxas que vêm sendo atualmente cobradas, já que estes são os usuários que mais lançam efluentes, sendo a deterioração da qualidade da água o problema de maior relevância nesta área da bacia.

Ruthenium, Rhodium, and Iridium Bis(σ-B−H) Diisopropylaminoborane Complexes

The coordination chemistry of diisopropylaminoborane H2B−NiPr2 with valence isoelectronic metal fragments to form, essentially isostructural, [MH2(η2:η2-H2B−NiPr2)(PCy3)2]n+ (M = Ru, n = 0; Rh and Ir, n = 1) has been explored by a combination of X-ray crystallography, NMR spectroscopy, and computational techniques. In the solid state and solution the aminoborane interacts with the metal centers through one four-center four-electron interaction, forming bis(σ-B−H) complexes. The structural data point to tighter interactions between both the Ru and Ir congeners compared to the Rh with significantly shorter M···B distances in the first two. These tighter interactions are mirrored in the spectroscopic data, with the Ru and Ir complexes showing more deshielded 11B chemical shifts and 1H M−H−B resonances that are more shielded than observed for the rhodium complex. Analysis of the bonding between metal and borane using the NBO approach is in very good agreement with the variations in the geometrical and spectroscopic parameters. There is overall a stronger interaction between the borane and the metal fragment for neutral Ru compared to cationic Rh, with cationic Ir in an intermediate situation.

Phase behavior of the confined Lebwohl-Lasher model

The phase behavior of confined nematogens is studied using the Lebwohl-Lasher model. For three-dimensional systems the model is known to exhibit a discontinuous nematic-isotropic phase transition, whereas the corresponding two-dimensional systems apparently show a continuous Berezinskii-Kosterlitz-Thouless-like transition. In this paper, we study the phase transitions of the Lebwohl-Lasher model when confined between planar slits of different widths in order to establish the behavior of intermediate situations between the pure planar model and the three-dimensional system, and compare with previous estimates for the critical thickness, i.e., the slit width at which the transition switches from continuous to discontinuous.

On the Orthocomplementation of State–Property–Systems of Contextual Systems

We adopt an operational approach to quantum mechanics in which a physical system is defined by the mathematical structure of its set of states and properties. We present a model in which the maximal change of state of the system due to interaction with the measurement context is controlled by a parameter which corresponds with the number N of possible outcomes in an experiment. In the case N=2 the system reduces to a model for the spin measurements on a quantum spin-1/2 particle. In the limit N→∞ the system is classical, i.e. the experiments are deterministic and its set of properties is a Boolean lattice. For intermediate situations the change of state due to measurement is neither ‘maximal’ (i.e. quantum) nor ‘zero’ (i.e. classical). We show that two of the axioms used in Piron’s representation theorem for quantum mechanics are violated, namely the covering law and weak modularity. Next, we discuss a modified version of the model for which it is even impossible to define an orthocomplementation on the set of properties. Another interesting feature for the intermediate situations of this model is that the probability of a state transition in general not only depends on the two states involved, but also on the measurement context which induces the state transition.

Functional diversity of herbaceous species under different fire frequencies in Brazilian savannas

Fire plays an important role in determining the structure of savannas, so that frequent fires tend to favor the herbaceous species in savannas. Functional diversity is a measure of the range of the species functional traits and is thought to be related to many functions and properties like community stability, nutrient cycling, and productivity, for example. We examined if functional diversity of herbaceous species was different along a fire gradient, and if observed functional diversity differed from a random assembly of species traits. We sampled three sites with different fire frequencies. According to the intermediate disturbance hypothesis, we expected the functional diversity to be higher in the intermediate fire frequency site. Subsequently, we excluded rare species from the analyses – species with less than ten individuals in each site – to verify their contribution to the observed patterns of functional diversity. We expected to find no difference with the exclusion of rare species. Functional diversity values, either considering all species or excluding the rare ones, were not different among sites, suggesting that (1) frequent fires may not affect overall functioning of the herbaceous community in savannas and (2) rare herbaceous species seem to present lower functional complementarity. According to the neutral theory, most of the herbaceous species may have evolved stochastically in niches more similar than competitive exclusion could allow. Also, functional diversity was not different from what one may expect by chance in any of the three sites. We also calculated the floristic similarity among sites. When we considered qualitative data, we found floristic differences between the sites of high and intermediate as well as between high and low fire frequency sites, but there was no difference between the intermediate and low fire frequency situation. Floristic similarities were different among all the three sites when the abundances of species were considered. Consequently, different fire conditions may change species composition without affecting the functional diversity of the herbaceous layer of savannas, corroborating the idea that savannas are more stable in functional than in floristic terms.

Application of the modified differential approximation for radiative transfer to arbitrary geometry

The first-order spherical harmonics method (or P 1 approximation) has found prolific usage for approximate solution of the radiative transfer equation (RTE) in participating media. However, the accuracy of the P 1 approximation deteriorates as the optical thickness of the medium is decreased. The modified differential approximation (MDA) was originally proposed to remove the shortcomings of the P 1 approximation in optically thin situations. This article presents algorithms to apply the MDA to arbitrary geometry—in particular, geometry with obstructions, and inhomogeneous media. The wall-emitted component of the intensity was computed using a combined view-factor and ray-tracing approach. The Helmholtz equation, arising out of the medium-emitted component, was solved using an unstructured finite-volume procedure. The general procedure was validated for both two-dimensional (2D) and three-dimensional (3D) geometries against benchmark Monte Carlo results. The accuracy of MDA was found to be superior to the P 1 approximation for all optical thicknesses. Its accuracy, when compared with the discrete ordinates method (both S 6 and S 8), was found to be clearly superior in optically thin situations, but problem dependent in optically intermediate and thick situations. For 3D geometries, calculation and storage of the view-factor matrix was found to be a major shortcoming of the MDA. In addition, for inhomogeneous media, calculation of optical distances requires a ray-tracing procedure, which was found to be a bottleneck from a computational efficiency standpoint. Several strategies to reduce both memory and computational time are discussed and demonstrated.

Sandstone dikes in dolerite sills: Evidence for high-pressure gradients and sediment mobilization during solidification of magmatic sheet intrusions in sedimentary basins

Sediment dikes are common within dolerite sill intrusions in the Karoo Basin in South Africa. The dikes are subvertical and as much as 2 m wide, sometimes with abundant fragments of sedimentary rocks and dolerite. The matrix consists of contact-metamorphic sandstone. There is no petrographic evidence for melting within the sediment dikes. The maximum temperature during heating is restricted to the plagioclase and biotite stability field, or above ∼350 °C. Thermal modeling of a sandstone dike in a dolerite sill shows that a temperature of 350–450 °C is reached in the dike after a few hundred years of sill cooling. The calculated pressure history of a cooling sill and its contact aureole shows that substantial fluid pressure anomalies develop on a short time scale (1–15 yr) and are maintained for more than 100 yr. Calculated pressure anomalies in the sill (-7 to -22 MPa) and the aureole (4–22 MPa) are significant and may explain sill fracturing and sediment mobilization from the aureole into the sill. We conclude that sediment dikes represent common features of sedimentary basins with sill intrusions in which fluid pressure gradients have been high. Sediment dikes thus signify that pore fluids may escape from the aureoles on a short time scale, representing an intermediate situation between fluid loss during formation of microfractures and fluid loss during violent vent formation.

Effect of an electric field on an intermittent granular flow

Granular gravity driven flows of glass beads have been observed in a silo with a flat bottom. A dc high electric field has been applied perpendicularly to the silo to tune the cohesion. The outlet mass flow has been measured. An image subtraction technique has been applied to visualize the flow geometry and a spatiotemporal analysis of the flow dynamics has been performed. The outlet mass flow is independent of voltage, but a transition from funnel flow to rathole flow is observed. This transition is of probabilistic nature and an intermediate situation exists between the funnel and the rathole situations. At a given voltage, two kinds of flow dynamics can occur: a continuous flow or an intermittent flow. The electric field increases the probability to observe an intermittent flow.

Surface investigation of carbon films: from diamond to graphite

AbstractIn the present work, a detailed spectroscopic investigation of carbon in different crystalline forms from diamond to graphite was carried out. The spectra of photoemission peak, plasmon losses and X‐rays‐excited C KLL were studied in order to characterize the carbon phase in different samples. In addition, a method for determination of sp2/sp3 ratio from the first derivative of Auger C KLL spectrum was employed. The obtained results indicated that carbon photoemission peak for sp2 and sp3 configurations is characterized by the same value of binding energy. The peaks of plasmon losses and Auger KLL transition were more diagnostic than C 1s photoemission peak, permitting to distinguish the sp2 and sp3 configurations. For intermediate situation, which is present in diamond‐like carbon (DLC), characterized by a mixture of sp2 and sp3 states, the spectra were very similar to the carbon‐black, whereas single‐wall carbon nanotubes (CNT) were containing about 50% sp2 states. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Symmetry and Asymmetry Level Measures

Usually, Symmetry and Asymmetry are considered as two opposite sides of a coin: an object is either totally symmetric, or totally asymmetric, relative to pattern objects. Intermediate situations of partial symmetry or partial asymmetry are not considered. But this dichotomy on the classification lacks of a necessary and realistic gradation. For this reason, it is convenient to introduce "shade regions", modulating the degree of Symmetry (a fuzzy concept). Here, we will analyze the Asymmetry problem by successive attempts of description and by the introduction of the Asymmetry Level Function, as a new Normal Fuzzy Measure. Our results (both Theorems and Corollaries) suppose to be some new and original contributions to such very active and interesting field of research. Previously, we proceed to the analysis of the state of art.

Analysis of Q-Value of Quartz-Crystal Tuning Fork by Use of Thermoelastic Coupling Equations Including an Effect of Thermal Radiation

We investigated a method of predicting the actual Q-value of a quartz-crystal tuning fork on the basis of thermoelastic coupling equations by considering an effect of thermal radiation from the flexural vibrating arms of the tuning fork to the external environment. We developed the method of calculating the quartz-crystal tuning fork's Q-value by use of a new temperature distribution solution, indicating an intermediate situation between adiabatic and isothermal solutions by use of a parameter α1 (0 ≦α1 ≦1; isothermal solution is given at α1 = 0 and adiabatic solution is given at α1 = 1) for the coupled heat conduction equation without a thermal radiation term, which was adjusted so as to have almost the same curve as the approximated temperature distribution including the zero-order and first-order temperature distribution solutions of the coupled heat conduction equation with the thermal radiation term, given by the perturbation method. Our calculated Q-value was closer to the measured value for an etching-processed quartz-crystal tuning fork than that obtained by the coupled heat conduction equation without the thermal radiation term under an adiabatic boundary condition.

HYMAD: Hybrid DTN-MANET routing for dense and highly dynamic wireless networks

Delay/Disruption-Tolerant Network (DTN) protocols typically address sparse intermittently connected networks whereas Mobile Ad-hoc Network (MANET) protocols address the fairly stable and fully connected ones. But many intermediate situations may occur on mobility dynamics or radio link instability. In such cases, where the network frequently splits into evolving connected groups, none of the conventional routing paradigms (DTN or MANET) are fully satisfactory. In this paper we propose HYMAD, a Hybrid DTN-MANET routing protocol which uses DTN between disjoint groups of nodes while using MANET routing within these groups. HYMAD is fully decentralized and only makes use of topological information exchanges between the nodes. The strength of HYMAD lies in its ability to adapt to the changing connectivity patterns of the network. We evaluate the scheme in simulation by replaying synthetic and real life mobility traces which exhibit a broad range of connectivity dynamics. The results show that HYMAD introduces limited overhead and outperforms the multi-copy Spray-and-Wait DTN routing protocol it extends, both in terms of delivery ratio and delay. This hybrid DTN-MANET approach offers a promising venue for the delivery of elastic data in mobile ad-hoc networks as it retains the resilience of a pure DTN protocol while significantly improving performance.