The impact of the Kasatochi eruption on the Moon's illumination during the August 2008 lunar eclipse

The Moon's changeable aspect during a lunar eclipse is largely attributable to variations in the refracted unscattered sunlight absorbed by the terrestrial atmosphere that occur as the satellite crosses the Earth's shadow. The contribution to the Moon's aspect from sunlight scattered at the Earth's terminator is generally deemed minor. However, our analysis of a published spectrum of the 16 August 2008 lunar eclipse shows that diffuse sunlight is a major component of the measured spectrum at wavelengths shorter than 600 nm. The conclusion is supported by two distinct features, namely the spectrum's tail at short wavelengths and the unequal absorption by an oxygen collisional complex at two nearby bands. Our findings are consistent with the presence of the volcanic cloud reported at high northern latitudes following the 7-8 August 2008 eruption in Alaska of the Kasatochi volcano. The cloud both attenuates the unscattered sunlight and enhances moderately the scattered component, thus modifying the contrast between the two contributions.Comment: Accepted for publication in Geophysical Research Letter

A Highly Available Cluster of Web Servers with Increased Storage Capacity

Ponencias de las Decimoséptimas Jornadas de Paralelismo de la Universidad de Castilla-La Mancha celebradas el 18,19 y 20 de septiembre de 2006 en AlbaceteWeb servers scalability has been traditionally solved by improving software elements or increasing hardware resources of the server machine. Another approach has been the usage of distributed architectures. In such architectures, usually, file al- location strategy has been either full replication or full distribution. In previous works we have showed that partial replication offers a good balance between storage capacity and reliability. It offers much higher storage capacity while reliability may be kept at an equivalent level of that from fully replicated solutions. In this paper we present the architectural details of Web cluster solutions adapted to partial replication. We also show that partial replication does not imply a penalty in performance over classical fully replicated architectures. For evaluation purposes we have used a simulation model under the OMNeT++ framework and we use mean service time as a performance comparison metric.Publicad

Coupling of morphology to surface transport in ion-beam irradiated surfaces. I. Oblique incidence

We propose and study a continuum model for the dynamics of amorphizable surfaces undergoing ion-beam sputtering (IBS) at intermediate energies and oblique incidence. After considering the current limitations of more standard descriptions in which a single evolution equation is posed for the surface height, we overcome (some of) them by explicitly formulating the dynamics of the species that transport along the surface, and by coupling it to that of the surface height proper. In this we follow recent proposals inspired by ``hydrodynamic'' descriptions of pattern formation in aeolian sand dunes and ion-sputtered systems. From this enlarged model, and by exploiting the time-scale separation among various dynamical processes in the system, we derive a single height equation in which coefficients can be related to experimental parameters. This equation generalizes those obtained by previous continuum models and is able to account for many experimental features of pattern formation by IBS at oblique incidence, such as the evolution of the irradiation-induced amorphous layer, transverse ripple motion with non-uniform velocity, ripple coarsening, onset of kinetic roughening and other. Additionally, the dynamics of the full two-field model is compared with that of the effective interface equation.Comment: 23 pages, 14 figures. Movies of figures 6, 7, and 8 available at http://gisc.uc3m.es/~javier/Movies

Astronomical Site Ranking Based on Tropospheric Wind Statistics

We present comprehensive and reliable statistics of high altitude wind speeds and the tropospheric flows at the location of five important astronomical observatories. Statistical analysis exclusively of high altitude winds point to La Palma as the most suitable site for adaptive optics, with a mean value of 22.13 m/s at the 200 mbar pressure level. La Silla is at the bottom of the ranking, with the largest average value 200 mbar wind speed(33.35 m/s). We have found a clear annual periodicity of high altitude winds for the five sites in study. We have also explored the connection of high to low altitude atmospheric winds as a first approach of the linear relationship between the average velocity of the turbulence and high altitude winds (Sarazin & Tokovinin 2001). We may conclude that high and low altitude winds show good linear relationships at the five selected sites. The highest correlation coefficients correspond to Paranal and San Pedro Martir, while La Palma and La Silla show similar high to low altitude wind connection. Mauna Kea shows the smallest degree of correlation, which suggests a weaker linear relationship. Our results support the idea of high altitude winds as a parameter for rank astronomical sites in terms of their suitability for adaptive optics, although we have no evidence for adopting the same linear coefficient at different sites. The final value of this linear coefficient at a particular site could drastically change the interpretation of high altitude wind speeds as a direct parameter for site characterization.Comment: 18 pages, 5 figures. Accepted in MNRA

Energy harvesting from vehicular traffic over speed bumps: A review

Energy used by vehicles to slow down in areas of limited speed is wasted. A traffic energy-harvesting device (TEHD) is capable of harvesting vehicle energy when passing over a speed bump. This paper presents a classification of the different technologies used in the existing TEHDs. Moreover, an estimation of the energy that could be harvested with the different technologies and their cost has been elaborated. The energy recovered with these devices could be used for marking and lighting of roads in urban areas, making transportation infrastructures more sustainable and environmentally friendly

What is a fair wage? Reference points, entitlements and gift exchange

We look at the effect of endogenous and exogenous wage setting institutions on wage offers and effort in the classic gift exchange experiments (Fehr, Kirchsteiger and Riedl, 1993). An exogenously imposed minimum wage at the competitive outcome lowers average wage offers. Workers do not negatively reciprocate and continue to offer high effort. In the endogenous wage setting institution, where workers first make wage proposals, wage offers increase marginally and average effort decreases relative to the baseline when wage proposals are not matched. Relative to the baseline, efficiency decreases in the minimum wage treatment while it marginally increases in the endogenous treatment. We find evidence that the institutional structure has important implications towards wage offers, effort and efficiency

Extended Parental Care in the Freshwater Shrimp Genus Dugastella Bouvier, 1912 (Decapoda, Atyidae, Paratyinae)

5 páginas, 1 figura.Parental care and extended parental care are known behaviours in decapod crustaceans (see Thiel, 2000, 2003). While parental care before hatching, which involves incubation of the eggs (carrying, cleaning, and aeration) by females, is a common behaviour in the majority of decapod taxa (with the exception of Dendrobranchiata), extended parental care is a rare behaviour in decapods, restricted only to some species of brachyuran crabs (Diesel, 1989, 1992, 1997; Diesel & Horst, 1995; Ng & Tan, 1995), hermit crabs (Hazlett, 1983; López Greco et al., 2004; Calado et al., 2006), astacid crayfishes (Johnston & Fiegel, 1997; Vogt & Tolley, 2004), and caridean shrimps (Duffy, 1996). In the majority of these cases, the parental female presents different types of parental activity towards the offspring after hatching, like habitat control, elimination of predators, or sharing meals. Also, there are some cases in which larvae develop transient structures that allow them to remain fixed to the pleopods of the female abdomen, like in astacids (see Vogt & Tolley, 2004) and several species of the genus Sclerocrangon Sars, 1883 (see Makarov, 1968; Lacoursière-Roussel & Sainte-Marie, 2009). However, the most infrequent cases of extended parental care in decapods are those where females carry their juvenile offspring under their abdomen after the hatched larvae develop there (cf. abdominal brood pouches, or incubation chamber). These cases have only been reported in one species of Brachyura, Tunicotheres moseri (Rathbun, 1918) (see Bolaños et al., 2004), and one caridean, the kangaroo shrimp Dugastella valentina (Ferrer Galdiano, 1924) (see Cuesta et al., 2006). Taking into account this last case, and considering that there are only two species in the genus Dugastella Bouvier, 1912, the objective of the present study was to corroborate whether the other species, D. marocana Bouvier, 1912, also presents the same behaviour. These two species have a a restricted distribution, D. valentina occurs in the Gulf of Valencia (southern Europe) and D. marocana is found in some localities of Morocco (northwestern Africa).Collections in Morocco by JEGM and JEGR were possible thanks to fundings provided by “CSIC Proyectos Intramurales Especiales” 2006 3 01 238 to JAC.Peer reviewe