Organic Molecules in the Galactic Center. Hot Core Chemistry without Hot Cores

We study the origin of large abundances of complex organic molecules in the Galactic center (GC). We carried out a systematic study of the complex organic molecules CH3OH, C2H5OH, (CH3)2O, HCOOCH3, HCOOH, CH3COOH, H2CO, and CS toward 40 GC molecular clouds. Using the LTE approximation, we derived the physical properties of GC molecular clouds and the abundances of the complex molecules.The CH3OH abundance between clouds varies by nearly two orders of magnitude from 2.4x10^{-8} to 1.1x10^{-6}. The abundance of the other complex organic molecules relative to that of CH3OH is basically independent of the CH3OH abundance, with variations of only a factor 4-8. The abundances of complex organic molecules in the GC are compared with those measured in hot cores and hot corinos, in which these complex molecules are also abundant. We find that both the abundance and the abundance ratios of the complex molecules relative to CH3OH in hot cores are similar to those found in the GC clouds. However, hot corinos show different abundance ratios than observed in hot cores and in GC clouds. The rather constant abundance of all the complex molecules relative to CH3OH suggests that all complex molecules are ejected from grain mantles by shocks. Frequent (similar 10^{5}years) shocks with velocities >6km/s are required to explain the high abundances in gas phase of complex organic molecules in the GC molecular clouds. The rather uniform abundance ratios in the GC clouds and in Galactic hot cores indicate a similar average composition of grain mantles in both kinds of regions. The Sickle and the Thermal Radio Arches, affected by UV radiation, show different relative abundances in the complex organic molecules due to the differentially photodissociation of these molecules.Comment: 18 pages, 10 Postscript figures, uses aa.cls, aa.bst, 10pt.rtx, natbib.sty, revsymb.sty revtex4.cls, aps.rtx and aalongtabl.sty. Accepted in A&A 2006. version 2. relocated figures and tables. Language editor suggestions. added reference

Participación vegetal en la construcción de los sistemas dunares litorales de Mallorca

[Resumen] Se establecen las relaciones entre la zonación vegetal y las áreas geomorfológicas de los sistemas dunares litorales de la isla de Mallorca. Para ello, se clasifican dichos sistemas en cuatro categorías en base a criterios morfológicos y de vegetación y se analiza la situación actual en cada uno de ellos, definiendose el papel que juega la vegetación en su arquitectura..[Abstract] The relationship between plant zonation and geomorphological areas have been studied in the coastal dunar systems of the island of Mallorca. Trough a four type classification based in vegetation and morphological criteria we point out their state of conservation and the role of the vegetation in their build-up

Design of an analog/digital truly random number generator

An analog-digital system is presented for the generation of truly random (aperiodic) digital sequences. This model is based on a very simple piecewise-linear discrete map which is suitable for implementation using monolithic analog sampled-data techniques. Simulation results are given illustrating the optimum choice of the model parameters. Circuit implementations are reported for the discrete map using both switched-capacitor (SC) and switched-current (SI) techniques. The layout of a SI prototype in a 3-μm n-well double-polysilicon double-metal technology is included

Conjunctival Melanoma: A New Clinical and Therapeutical Approach

Melanoma involving the conjunctiva is extremely rare. Graver prognosis has been reported with primary conjunctival melanoma than with their cutaneous counterparts [Collin et al.: Aust N Z J Ophthalmol 1986;14:29–34]. Among conjunctival melanomas, two significant risk factors for tumour-related death have been identified: (i) age older than 55 years and (ii) unfavourable tumour location (caruncle, cornea, fornix, palpebral conjunctiva) [Werschnik and Lommatzsch: Am J Clin Oncol 2002;25:248–255]. Here we present a rare case of lentigo maligna involving the palpebral, bulbar conjunctiva and the caruncle. We describe dermoscopic patterns observed and the use of a novel ocular melanoma therapy with topical imiquimod

A Decision Tree and S-Transform Based Approach for Power Quality Disturbances Classification

In this paper, it is presented an automated classification based on S-transform as feature extraction tool and Decision Tree as algorithm classifier. The signals generated according to mathematical models, including complex disturbances, have been used to design and test this approach, where noise is added to the signals from 40dB to 20dB. Finally, several disturbances, simple and complex, have been considered to test the implemented system. Evaluation results verifying the accuracy of the proposed method are presented.IEE

Adsorption of antipyrine by activated carbons from FeCl3-activation of Tara gum

Activated carbons were synthesized by FeCl3-activation of Tara gum at different temperatures (400–1000 °C). The activating agent and the precursor were physically mixed at different ratios (r= FeCl3:precursor, 0.5–3.0 wt). At r=2 and 800 °C the most developed porosity was achieved, with a BET surface area of 1680 m2·g-1 and a pore volume near 1 cm3·g-1, corresponding mostly to micropores (˜75%). The carbons were fully characterized and tested for the aqueous-phase adsorption of antipyrine, used as model emerging pollutant. The kinetic curves and adsorption isotherms at 20, 40 and 60 °C were obtained, which fitted well to hyperbolic and Langmuir equations, respectively. At 20 °C, the saturation adsorption capacity was around 275 mg·g-1 AC. The free energy of adsorption varied from -40.2 to -35.7 kJ·mol-1, while values close to -3 kJ·mol-1 and 112 J·mol-1·K-1, were obtained for the enthalpy and entropy of adsorption, respectively