Of all the known pillared layered clays (PILC), Al-PILC is the most studied. In spite of that, its use on a commercial scale is not yet possible due to the large amount of water required for its synthesis. The aim of the present work was to take advantage of the beneficial effects of ultrasound radiation for reducing intercalation time, and to optimize the synthesis parameters in order to find a viable industrial means of preparing Al-PILC.

A comprehensive study of the effect of ultrasonic radiation on the parameters which have a direct effect on the amount of water used in the synthesis was conducted, specifically on the effects of: (1) mmol of Al/g of clay ratio (R) by decreasing the volume of A1 solution and keeping the amount of clay constant, (2) the concentration of clay in the initial suspension (or not suspending the clay at all), and (3) the concentration of the A1 precursor solution. The use of ultrasonic radiation produced the expected reduction in exchange time which was attributed to a decrease of the clay-particle size. This decrease of particle size gave rise to an improvement in the diffusion of the A1 precursor towards the core of the clay grain leading to solids with increased surface areas, basal spacing and X-ray diffraction peak definition. By optimizing the synthesis parameters directly involved in the consumption of water, it was possible to decrease the amount used by >60%.

The magnitude of facilitation by shelter-building engineers on community structure is expected to be greater when they increase limited resources in the environment. We evaluated the influence of local environmental context on the colonisation of leaf shelters by arthropods in a Mexican evergreen tropical rainforest. We compared the species richness and abundance of arthropods (total and for different guilds) colonising artificially rolled leaves in habitats differing in understory heterogeneity (forest edge > old-growth forests > living fences). Arthropod abundance of the most representative arthropod taxa (i.e., Araneae, Blattodea, Collembola and Psocoptera) colonising the rolled leaves was greater at forest edge, a trend also observed for average arthropod abundance, and for detritivore and predator guilds. In addition, fewer arthropod species and individuals colonised the rolled leaves in the living fence habitat, a trend also observed for most arthropod guilds. As forest edge is expected to have a greater arthropod diversity and stronger density-dependent interactions, a greater limitation of refuges from competitors or predators may have determined the higher colonisation of the rolled leaves in this habitat. Our results demonstrate that local environment context is an important factor that affects the colonisation of arthropods in leaf shelters.

Human-computer hybrid teams can meet challenges in designing complex engineered systems. However, the understanding of interaction in the hybrid teams is lacking. We review the literature and identify four key attributes to construct design research platforms that support multi-phase design, hybrid teams, multiple design scenarios, and data logging. Then, we introduce a platform for unmanned aerial vehicle (UAV) design embodying these attributes. With the platform, experiments can be conducted to study how designers and intelligent computational agents interact, support, and impact each other.

This paper addresses the chemical synthesis and characterization of a composite formed by Li2O-Al2O3-Al3Fe-Al3Fe5O12/PCL which were obtained by the process of reduction of ferric chloride (FeCl3) with lithium aluminum hydride (LiAlH4) in an open atmosphere. The goal of the development of this hybrid material was to perform a superparamagnetic material with several potential applications. The results of the characterizations by scanning electron microscopy (SEM) and vibrating sample magnetometer showed a Li2O-Al2O3-Al3Fe-Al3Fe5O12 “desert rose stone”-like morphology 3D hierarchical powders formation when particles were sintered at 850 °C. Homogeneous nanometric particles after calcination at 1100 °C were observed. X-ray diffraction analysis were performed to determine their composition. Subsequently, the superparamagnetic powders were added by dispersion in a polycaprolactone (PCL) matrix, and then, were evaluated by SEM for the observation of their morphologies. The composite material presented a polymer network with an opened structure, a well dispersion of the oxides particles into the interstices with irregular topography and reliefs.

Una sepiolita procedente de Toledo (España) se ha activado por tratamiento con disoluciones 0·25, 0·50 y 0·75 n de NO3H, seguido de calentamiento durante 10 h a 110, 200, 300, 400 y 500°C. Para cualquier concentración ácida, un calentamiento de 110, 200 y, a veces, 300°C, produce un aumento del número de poros mientras que las temperaturas superiores significan un cierre de los mismos tanto mayor cuanto más elevada es la temperatura de tratamiento. El máximo desarrollo de la superficie accesible al N2 tiene lugar con una disolución 0·50 n de NO3Hy 200°C (449 m2/g, método de BET); la superficie específica de la sepiolita natural es de 321 m2/g.

Porosity development in a sepiolite from Toledo, Spain, has been studied as a function of acid (0·25, 0·50, 0·75 and 1·0 m HNO3) and subsequent heat treatments (110–400°C). Adsorption isotherms of N2 at 77 K have been analysed by f-plot, t-plot, αs-plot and the Cranston & Inkley methods. Results are compared with those obtained on products heated without previous acid activation. Experimental conditions favouring porosity development are discussed.

The variations in surface area of a sepiolite (Toledo, Spain) after acid and heat treatments (1 n to 5 n, HNO3, 110°C to 900°C for 100 h) have been studied. Surface areas have been determined from N2 adsorption isotherms at 77 K using B.E.T., Langmuir and Dubinin-Radushkevich equations. SBET values range from 65 up to 391 m2 g−1, the maximum value corresponding to the sample activated with 1 n HNO3 solution and treated at 300°C. SL and SD-R values are similar, but slightly larger than the corresponding SBET values.

A correlated study has been carried out with samples activated with 1 n and 2 n HNO3 solutions and heat treated at 110, 200, 300, 400 and 500°C for 10 h. SBET values of these samples are rather similar to those of the corresponding samples treated during 100 h.

Colistin resistance mediated by the mcr-1 gene has been reported worldwide, but to date not from the Andean region, South America. We report the first clinical isolate of Escherichia coli harbouring the mcr-1 gene in Ecuador. The strain was isolated from peritoneal fluid from a 14-year-old male with acute appendicitis, and subjected to molecular analysis. The minimum inhibitory concentration of colistin for the strain was 8 mg/ml and it was susceptible to carbapenems but resistant to tigecycline. The strain harboured mcr-1 and blaCTX-M-55 genes and was of sequence type 609. The recognition of an apparently commensal strain of E. coli harbouring mcr-1 serves as an alert to the presence in the region of this recently described resistance mechanism to one of the last line of drugs available for the treatment of multi-resistant Gram-negative infections.

There are two principal problems in explaining, in terms of the emission from OB stars, the ionisation of gas which emits diffuse Hα in spiral galaxies. One is the long pathlength which the ionising photons need to traverse to reach their objectives, the other is whether sufficient photons can escape from within the H II regions which surround the hot stars. Here we treat the second point, assuming that the H II regions above a certain threshold luminosity are density bounded. We calculate the escaping Lyman continuum (Lyc) fluxes from the density bounded regions in four galaxies, and show that in each of them this is easily suffcient to produce the measured diffuse Hα emission.

Galactic winds and outflows are an ubiquitous phenomenon in galaxies with active star formation and/or active nuclei. They constitute the main mechanism for redistributing dust and metals on large scales and are therefore a key ingredient to understand the life cycle of galaxies. Among galaxies, ULIRGs are of particular interest in this context, as they host intense starbursts and are likely to be the dominant star formers at z > 1. These objects have been shown to host important winds, but it is not yet known what is the frequency of galactic winds and their properties in galaxies with lower star formation rates (SFR). We are studying galactic winds in a sample of 21 galaxies with different SFRs (including ULIRGs) from observations with the INTEGRAL fiber spectrograph on the 4.2m WHT. In order to be able to address the complex multi–phase nature of the wind phenomenon, we have used the Na I D doublet absorption lines to trace cold gas, and a few emission lines (Hα, [N ii] and [S ii]) to trace the warmer ionized gas of the wind. The distribution and kinematics of both components in these objects is then analysed. Preliminary results show strong spatial correlation between regions with high non–circular velocities, areas with high star formation activity and regions with two different components in the emission lines. This set of data will help us to characterise the distribution and kinematics of the winds and their relation with the host galaxy type.

A study of the fluid flow in a mixing device proposed to dissolve alloying elements in iron baths is performed through a mathematical model in order to predict the best operating conditions for a proper melting/dissolution of solid alloying particles. The mathematical model consists in the mass and momentum conservation equations (continuity and Turbulent Navier-Stokes equations), and the standard two k-epsilon turbulence model. The model is numerically solved in transient regime with the Volume of Fluid algorithm (VOF) to calculate the vortex shape. VOF is built-in the CFD (Computational Fluid Dynamics) software ANSYS FLUENT 14. A flow of metal enters tangentially in the mixing chamber of the proposed mixing device (taken from an open patent) to generate a vortex. The shape and height of the vortex reached in this chamber depends on several design variables, but in this work only the presence or absence of a barrier in the device is analyzed. Results are obtained on the vortex sizes and shapes, liquid flow patterns, turbulent structure, residence times of the particles of alloying elements added to the melt and mixing times (Residence time distribution curves) of two devices: one with a barrier and the other without this barrier. It is found that the presence of the barrier in the device increases turbulence, destroys the vortex, decreases the residence time of the particles, and decreases the volume of fluid in the device. Most of the features of the barrier are detrimental for mixing and inhibits melting/dissolution of the alloying elements. Then, it is suggested a device without the presence of barrier for better performance.

Latin America has a high rate of community-associated infections caused by multidrug-resistant Enterobacteriaceae relative to other world regions. A review of the literature over the last 10 years indicates that urinary tract infections (UTIs) by Escherichia coli, and intra-abdominal infections (IAIs) by E. coli and Klebsiella pneumoniae, were characterized by high rates of resistance to trimethoprim/sulfamethoxazole, quinolones, and second-generation cephalosporins, and by low levels of resistance to aminoglycosides, nitrofurantoin, and fosfomycin. In addition, preliminary data indicate an increase in IAIs by Enterobacteriaceae producing extended-spectrum β-lactamases, with reduced susceptibilities to third- and fourth-generation cephalosporins. Primary-care physicians in Latin America should recognize the public health threat associated with UTIs and IAIs by resistant Gram-negative bacteria. As the number of therapeutic options become limited, we recommend that antimicrobial prescribing be guided by infection severity, established patient risk factors for multidrug-resistant infections, acquaintance with local antimicrobial susceptibility data, and culture collection.

The X-ray transient source XTE J1818–245 went through an outburst in 2005 that was observed during a multi-wavelength campaign from radio to soft γ-rays. We performed new optical observations with the ESO/NTT telescope at La Silla. The broad-band spectral energy distribution revealed that the outer parts of the accretion disc had to be irradiated by its inner parts to explain the optical emission.

Binary encounters between spherical particles in shear flow are studied for a system bounded by a single planar wall or two parallel planar walls under creeping flow conditions. We show that wall proximity gives rise to a new class of binary trajectories resulting in cross-streamline migration of the particles. The spheres on these new trajectories do not pass each other (as they would in free space) but instead they swap their cross-streamline positions. To determine the significance of the wall-induced particle migration, we have evaluated the hydrodynamic self-diffusion coefficient associated with a sequence of uncorrelated particle displacements due to binary particle encounters. The results of our calculations quantitatively agree with the experimental value obtained by Zarraga & Leighton (Phys. Fluids, vol. 14, 2002, p. 2194) for the self-diffusivity in a dilute suspension of spheres undergoing shear flow in a Couette device. We thus show that the wall-induced cross-streamline particle migration is the source of the anomalously large self-diffusivity revealed by their experiments.

During the first year in operation, INTEGRAL has detected more than 28 new bright sources which emit the bulk of their emission above 10 keV. Follow-up observations of a subset of these sources in the X-ray band with XMM-Newton indicate that 80% of them are very strongly absorbed. More than half of these absorbed sources show strong pulsations with long periods ranging from 139 to 1300s, i.e., they are slow X-ray pulsars. Many of these new sources are super-giant high-mass X-ray binaries (HMXB) in which the stellar wind of the companion star is accreted onto the compact object. The large local absorption in these new sources can be understood if the compact objects are buried deep in their stellar winds. These new objects represent half of the population of active super-giant HMXB.

IGR J17252–3616 is the hard X-ray counterpart of EXO 1722–363. The regular monitoring by INTEGRAL shows that IGR J17252–3616 is a persistent source with an average count rate of $\sim$6.4 mCrab in the 20–60 keV energy band. A follow-up observation with XMM-Newton showed that the source is located at R.A. (2000.0) $=17^{h}25^{m}11.4^{s}$ and Dec. $=-36{\hbox{$^\circ$}} 16 {\hbox{$^\prime$}} 58.6 \hbox{$^{\prime\prime}$}$ with an uncertainty of $4 \hbox{$^{\prime\prime}$}.

The source is a binary X-ray pulsar with a spin period of 413.7 s. The spectral shape is typical for an accreting pulsar except that a huge intrinsic absorption and a cold iron fluorescence line are detected. The absorbing column density and cold iron line do not vary with the pulse period. The observations suggest that the source is a wind-fed accreting pulsar accompanied by a supergiant star.

An analysis of the high-energy emission from IGR J16393–4643 is presented using data from INTEGRAL and XMM-Newton. The source is persistent in the 20–40 keV band at an average flux of $5.1\times10^{-11}$ergs cm$^{-2}$ s$^{-1}$, with variations in intensity by at least an order of magnitude. A pulse period of 912$\,{\pm}\,$3 s was discovered in the ISGRI and EPIC light curves. The source spectrum is a strongly-absorbed ($N_{\mathrm{H}}=(2.5\,{\pm}\,0.2)\times10^{23}$ cm$^{-2}$) power law that features a high-energy cutoff above 15 keV. Two iron emission lines at 6.4 and 7.1 keV, an iron absorption edge $\gtrsim$7.1 keV, and a soft excess emission of $7\times10^{-15}$ergs cm$^{-2}$ s$^{-1}$ between 0.5–2 keV, are detected in the EPIC spectrum. The shape of the spectrum does not change with the pulse. Its persistence, pulsation, and spectrum place IGR J16393–4643 among the class of heavily-absorbed HMXBs. The improved position from EPIC is R.A. (J2000)$=16^{\mathrm{h}}39^{\mathrm{m}}05.4^{\mathrm{s}}$ and Dec.$=-46^{\circ}42'12''$ ($4''$ uncertainty) which is compatible with that of 2MASS J16390535–4642137.

We present the results of optical and infrared photometry of the quiescent X-ray transient V404 Cyg during the period 1992-2003.

It is largely known that the Soft X-ray Transient (SXT) V404 Cyg exhibits short-term (sub-orbital) variations during quiescence (see eg. Pavlenko et al. 1996). It seems that fast variability during quiescence is not a peculiarity of V404 Cyg but a fingerprint of quiescent SXTs, irrespective of the nature of the compact object (Zurita, Casares & Shahbaz, 2003). Although these variations seem to originate in the accretion disc, the underlaying physical mechanism is not yet understood. Since V404 Cyg is the brightest SXT, and hence accessible with 1-m type telescopes, we embarked on a study of the fast variability over the period 1992-2003.