Cryptophagids from the Maltese Islands with description of a new species of Micrambe THOMSON (Coleoptera: Cryptophagidae)

The Cryptophagidae (Coleoptera) of the Maltese Islands are reviewed based on material of earlier records and recent collections. A total of twelve species are reported, of which Micrambe mediterranica OTERO & JOHNSON sp.n. is described from material collected in Malta, Greece and Jordan.peer-reviewe

Assessment of joint inventory replenishment: a cooperative games approach

This research deals with the design of a logistics strategy with a collaborative approach between non-competing companies, who through joint coordination of the replenishment of their inventories reduce their costs thanks to the exploitation of economies of scale. The collaboration scope includes sharing logistic resources with limited capacities; transport units, warehouses, and management processes. These elements conform a novel extension of the Joint Replenishment Problem (JRP) named the Schochastic Collaborative Joint replenishment Problem (S-CJRP). The introduction of this model helps to increase practical elements into the inventory replenishment problem and to assess to what extent collaboration in inventory replenishment and logistics resources sharing might reduce the inventory costs. Overall, results showed that the proposed model could be a viable alternative to reduce logistics costs and demonstrated how the model can be a financially preferred alternative than individual investments to leverage resources capacity expansions. Furthermore, for a practical instance, the work shows the potential of JRP models to help decision-makers to better understand the impacts of fleet renewal and inventory replenishment decisions over the cost and CO2 emissions.DoctoradoDoctor en Ingeniería Industria

Experimental results on evaporation waves

We address an experimental investigation of evaporation waves. They are obtained when a liquid contained in a vertical glass tube is suddenly depressurized from a high initial pressure down to the atmospheric one. After the release of pressure, the state of the liquid, which is at ambient pressure and the initial temperature, is well known to be metastable when the corresponding stable state is vapour. For moderately large evaporation rates (moderately large initial to ambient pressure ratios), the vapour-liquid interface ultimately evolves into an evaporation wave in which a highly corrugated front propagates downwards into the liquid with a well defined mean velocity. This mean velocity turns out to be a function of the ratio between the initial and the ambient pressures. In addition, attention to some new phenomena not previously reported is brought

Fundamentals and Applications of Surface-Enhanced Raman Spectroscopy (SERS)

When a molecule is adsorbed on some metallic nanostructured surfaces such as silver, copper or gold, it can undergo an enormous enhancement of the Raman signal giving rise to the so called Surface-Enhanced Raman Scattering (SERS). The high sensitivity of this effect allows an accurate structural study of adsorbates at very low concentrations. The SERS effect has historically been associated with the substrate roughness on two characteristic length scales. Surface roughness on the 10 to 100 nm length scale supports localized plasmon resonances which are considered as the dominant enhancement mechanism of SERS (Electromagnetic Enhancement Mechanism: SERS-EM). It is usually accepted that these electromagnetic resonances can increase the scattered intensity by an average factor of ca. 104 to 107. A secondary mechanism often thought to require atomic scale roughness is referred to as Charge Transfer (CT) Enhancement Mechanism (SERS-CT). This mechanism involves the photoinduced transfer of an electron from the metal to the adsorbate or vice versa and involves new electronic excited CT states which result from adsorbate–substrate chemical interactions. It is also estimated that such SERS-CT mechanism can enhance the scattering cross-section by a factor of ca. 10 to 102. These two mechanisms can operate simultaneously, depending on the particular systems and experimental conditions, making difficult to recognize each one and to estimate their relative magnitude in a particular spectrum.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Live lecture screencast recording: a proposal to simplify the tasks associated with content production for video-teaching

Se trata de un resumen (Abstract) de la contribución. El acuerdo de transferencia de copyright del trabajo completo es incompatible con el depósito del mismo en RIUMA.Se describe la implementación inicial de un método simplificado de grabación en directo de sesiones de clase en asignaturas de las Escuelas de Ingeniería de la Universidad de Málaga. La simplificación se logra al incorporar en la actividad diaria del aula ciertas características típicas de la grabación en diferido de mini videos docentes. En una configuración mínima se graba únicamente el audio y el video en pantalla de la clase, evitando los desafíos técnicos y las dificultades que implica la grabación de otros elementos como la pizarra. Esto implica el uso de anotaciones en pantalla en tiempo real para reemplazar completamente las anotaciones en la pizarra.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. I Plan Propio Integral de Docencia. Universidad de Málaga. Universidad de Málaga. Vicerectorado de Personal Docente e Investigador, Proyectos de Innovación Educativa (PIE 17-018

Surface-Enhanced Raman spectroscopy of thiobenzoic acid on metal nanoparticles

Molecules adsorbed on some metal surfaces such as silver, copper and gold, can exhibit enormous Surface-enhanced Raman Scattering (SERS). The SERS effect has historically been associated with substrate roughness on two characteristic length scales [1,2]. Surface roughness on the 10 to 100 nm length scale supports the electromagnetic resonances which are the dominant mechanism of enhancement. A second mechanism often thought to require atomic scale roughness, is referred to as the chemical enhancement mechanism. This second mechanism involves the creation of new electronic excited states which result from adsorbate–substrate chemical interactions. These two mechanisms operate simultaneously making it difficult to isolate the role and magnitude of each one. In this work the SERS spectra of thiobenzoic acid (TBA) adsorbed on several silver colloids are recorded by using different excitation wavelengths. Taking advantage of the fact that SERS spectroscopy is both, surface selective and highly sensitive, we have attempted to determine the molecular structure of the surface complex once TBA is adsorbed on the metal. The analysis of the vibrational wavenumbers of the Raman and SERS spectra suggests that this molecule shows unidentate coordination to the silver surface through the sulphur atom. In order to confirm this conclusion DFT calculations have been carried out for different TBA-silver complexes concluding that the unidentate coordination is the most likely interaction of TBA on the metal surface. Wavelength-scanned SERS excitation spectroscopy involves the measurement of SERS signal by using several excitation wavelengths and it was recognized as a useful tool for checking the mechanisms responsible for the SERS enhancement [3]. We have studied the effect of the wavelength within the SERS spectra of TBA on silver colloid prepared by different methods and we have analyzed the intensity of the 8a vibrational mode of TBA recorded at about 1590 cm-1. The intensity of this mode is noticeably higher in the spectrum recorded with the 514.5 nm line (Fig. 1). This result is attributed to the presence of a resonant Raman effect associated to a photoinduced charge-transfer process when using the most energetic excitation line. Finally, it is important to mention the high affinity of TBA for the silver surfaces what allows for a detection limit estimated to be 0.01 microM.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Raman, SERS and DFT study of chemically-adsorbed thiobenzoic acid on silver nanoparticles

Thiocarboxylic acids are organosulphur compounds with general formula RC(O)SH. They are related to carboxylic acids by the replacement of one oxygen by sulphur. Two tautomers are possible, written as RC(S)OH and RC(O)SH. The second one is the majority species in solid state and solution of thiobenzoic acid (TBA) at room temperature [1], but derivatives from both tautomers are known so that the SERS spectrum can be originated by either one. Taking advantage of the fact that SERS spectroscopy is both surface selective and highly sensitive we have attempted to determine the molecular structure of TBA once it is adsorbed on the metal surface. To accomplish this SERS spectra of TBA have been recorded on different silver colloids. A combination of layer-by-layer method with spin-coating deposition of silver nanoparticles have been used to prepare SERS active substrates on which the homogeneity of the SERS signal of TBA has been analyzed. Fig. 1 (I) shows the Raman spectra of TBA in the neat liquid (a), 1 M aqueous solution at pH 14 (b), SERS spectrum of a 5x10-4 M silver colloid prepared by reduction of silver nitrate with sodium borohydride at pH 7 (c) and SERS spectrum of a 5x10-4 M silver colloid prepared by reduction of silver nitrate with hydroxylamine hydrochloride (d). The assignment of the Raman spectra has been based on the present work as well as on previous studies [2-4]. The two bands recorded at 1662 and 2572 cm-1 in Fig.1a, are assigned to (C=O) and (SH) modes, what confirms that the Raman spectrum in the neat liquid is due to the thiolic specie of TBA, RC(O)SH. In the Raman spectrum of the solution (Fig. 1b) a significant redshift of (C=O) mode of 52 cm-1 and the absence of the (SH) band are detected in agreement with the behavior observed in the SERS spectrum (Fig. 1c). The latter confirms that the thiol tautomer of thiobenzoate anion, RC(O)S-, is adsorbed on silver nanoparticles. Other important SERS enhancements have been registered for the following vibrational modes: 8a;ring, (C=O) and (CS) recorded at 1592, 1554 and 928 cm-1 in Fig. 1c and 1d, respectively. The last two modes, (C=O) and (CS), undergo wavenumber shifts of +40 and -40 cm-1 respectively, which are closely related with the coordination of thiobenzoate anion to the metal surface [5]. The analysis of the vibrational wavenumber of these modes suggests that this molecule shows unidentate coordination through the sulphur atom to the metal surface. In order to confirm this fact DFT calculations have been carried out for different silver complexes: I) bridging bidentate ligand, (II) chelating ligand and (III and IV) unidentate ligand (Fig. 2). Theoretical wavenumber of representative bands of these compounds have been compared to the experimental one concluding that the behavior of the unidentate ligand (III) is the most probably coordination type of TBA on the metal surface. In order to confirm these conclusions the SERS spectra of TBA on silver colloid prepared by reduction of silver nitrate with hydroxylamine hydrochloride at different concentration of analyte have been recorded as well (Fig. 1 (II)). It is well known that the SERS enhancement factor depends strongly on different factors and in particular on the adsorption properties of the probe and the analyte concentration on the surface coverage. In this sense TBA has shown a very good detection level for this particular silver colloid it being a highly SERS active molecule. The detection limit is estimated to be 0.01 molar. Finally, Fig. 3 shows a representative Raman mapping of TBA adsorbed on a silver substrate prepared by spin-coating. Generally speaking, the image represents a fairly homogeneous distribution of the SERS intensity highlighting some points where the intensity is stronger as is expected in areas with heterogeneous coverage. The reproducibility of this type of substrate is under study focusing their application as reproducible and ultrasensitive sensing assemblies by using TBA as the target molecule due its good SERS sensitivity.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Highly effective SERS nanopattern substrate. The enhancement is demonstrated using thiophenol as a molecular probe

The number of different types of Surface-enhanced Raman Scattering (SERS) substrates available for experimentation is increasing at high speed. New alternatives are introduced and explored every year in the literature including both novel nano-particles in solution as well as self-assembled or engineered structures with different levels of control over their optical properties. In this work silver nanopattern obtained by the nano-sphere lithography approach was prepared and characterized by AFM. This method basically exploits the regular patterns formed by self-assembly of dielectric (polystyrene, PS) nano-spheres on a surface upon drying. The evaporation of a silver film on top of the array can be followed by the lift-off of the nano-spheres themselves in which case an array of interstitial sites is left on the surface [1-2] (Fig. 1). We have observed in the AFM images that the shape of the nanopatterns is regular but the surface is rough and they are homogeneously distributed with dimensions in the sub-wavelength range.SERS properties of this substrate were examined by using thiophenol (TP) as molecular probe through the preparation of self-assembled monolayer (SAM) by dipping the substrates for 1h in 0.1mM solution of TP in CH2Cl2 at the temperature of 25ºC. Samples were subsequently rinsed with solutions solvents and dried before scanning. The surface interaction of this molecule has been studied by several groups and the most significant Raman change after the adsorption is the disappearance of the S-H stretching mode at about 2566 cm-1 in the SERS spectrum and indicating that an Ag-S bond has been formed [3]. The reproducibility on different areas of this substrate has been analyzed by using this molecular probe concluding that a fairly homogeneous distribution of the SERS intensity is observed (Fig. 2) which is a prerequisite for applications as ultrasensitive sensing assemblies.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Review of the genus Cryptophagus Herbst, 1863 (Coleoptera Cryptophagidae) from Georgia.

Cryptophagus axillaris Reitter, 1875 from Savekuo Cave is recorded for the beetle fauna of the Caucasus for the first time, while C. lycoperdi (Scopoli, 1763) from Bichvinta (=Pitsunda) is a new record for Georgian beetle fauna. Twenty five species of the Cryptophagus beetles are recorded in Georgia. Sampling data and distribution map for the genus Cryptophagus species are given. Identification key to the genus Cryptophagus in Georgia is provided

Un modelo tridimensional de producción de icebergs: experimentos numéricos en el glaciar Johnsons, Isla Livingston, Antártida

Las leyes de producci´on de icebergs m´as usuales son: 1) la que considera que la tasa de producci´on de icebergs depende linealmente de la profundidad de agua en el frente glaciar, seg´un una ley obtenida mediante ajustes a observaciones de campo; y 2) aqu´ella en la que el criterio de producci´on de icebergs viene dado por la altura del glaciar sobre el nivel de flotaci´on. El principal problema de la primera es que las relaciones emp´ıricas var´ıan ampliamente de un glaciar a otro, y tambi´en var´ıan con el tiempo, lo que no las hace adecuadas para modelos evolutivos de glaciares, mientras que la mayor desventaja de la segunda es que su aplicaci´on queda restringida a glaciares con frente no flotante. El nuevo criterio de producci´on de icebergs propuesto recientemente por Benn et al. [2] considera que el mecanismo primario de la producci´on de icebergs es la propagaci´on vertical de las grietas superficiales desarrolladas cerca del frente como consecuencia del r´egimen de tensiones extensivas. Este criterio permite el desarrollo de lenguas glaciares flotantes y puede ser utilizado en modelos evolutivos de din´amica glaciar. Sus principales limitaciones son su car´acter bidimensional y la excesiva simplicidad de los modelos din´amicos empleados. Hemos desarrollado una extensi´on tridimensional de este criterio que resuelve el sistema de Stokes completo de la din´amica glaciar, superando as´ı las dos limitaciones mencionadas. Hemos aplicado este modelo al glaciar Johnsons, en Isla Livingston (Ant´artida), mostrando los resultados que, si consideramos la presencia de un cierto volumen de agua de fusi´on en las grietas, las predicciones del modelo se ajustan bastante bien a las observaciones. No obstante, se requieren mejoras en la ley de deslizamiento del glaciar sobre su lech