A study toward development of an automated microbial metabolism laboratory Monthly progress report

Life detection systems based on phosphate and sulfur uptake for automated microbial metabolism laborator

Review of the West Indian species of Efferia Coquillett (Diptera: Asilidae): Part 1. Bahamas, Cayman Islands, Cuba, and Jamaica

The genus Efferia Coquillett from the Bahamas, Cayman Islands, Cuba, and Jamaica is reviewed. The fauna now totals 16 species with 6 new species described (Ef. bellardii n. sp., Ef. bromleyi n. sp., Ef. hinei n. sp., Ef. insula n. sp., Ef. pina n. sp., and Ef. vinalensis n. sp.). Cuba has the greatest diversity with 10 species, Jamaica 3, the Bahamas 2, and the Cayman Islands 1. Efferia stylata (Fabricius) is removed from the species list of these West Indian islands. The wings of Ef. caymanensis Scarbrough and Ef. bromleyi, spermathecae of Ef. bromleyi, Ef. cubensis (Bromley), Ef. insula, Ef. nigritarsis (Hine), and terminalia of all species are illustrated. Keys for the identification of the species are provided. Specimens of two additional species from Cuba are in too poor a condition to be described but their terminalia are illustrated and the species are included in the key to the males

Life Detection Subsystem Progress Report No. 1

Radioisotopic biochemical probe for extraterrestrial life detection based on cell uptake of phosphate and sulfu

Mode stability in delta Scuti stars: linear analysis versus observations in open clusters

A comparison between linear stability analysis and observations of pulsation modes in five delta Scuti stars, belonging to the same cluster, is presented. The study is based on the work by Michel et al. (1999), in which such a comparison was performed for a representative set of model solutions obtained independently for each individual star considered. In this paper we revisit the work by Michel et al. (1999) following, however, a new approach which consists in the search for a single, complete, and coherent solution for all the selected stars, in order to constrain and test the assumed physics describing these objects. To do so, refined descriptions for the effects of rotation on the determination of the global stellar parameters and on the adiabatic oscillation frequency computations are used. In addition, a crude attempt is made to study the role of rotation on the prediction of mode instabilities.The present results are found to be comparable with those reported by Michel et al. (1999). Within the temperature range log T_eff = 3.87-3.88 agreement between observations and model computations of unstable modes is restricted to values for the mixing-length parameter alpha_nl less or equal to 1.50. This indicates that for these stars a smaller value for alpha_nl is required than suggested from a calibrated solar model. We stress the point that the linear stability analysis used in this work still assumes stellar models without rotation and that further developments are required for a proper description of the interaction between rotation and pulsation dynamics.Comment: 8 pages, 4 figures, 3 tables. (MNRAS, in press

Role of Membrane GM1 on Early Neuronal Membrane Actions of Aβ During Onset of Alzheimer\u27s Disease

The ability of beta-amyloid peptide (Aβ) to disrupt the plasma membrane through formation of pores and membrane breakage has been previously described. However, the molecular determinants for these effects are largely unknown. In this study, we examined if the association and subsequent membrane perforation induced by Aβ was dependent on GM1levels. Pretreatment of hippocampal neurons with D-PDMP decreased GM1 and Aβ clustering at the membrane (Aβ fluorescent-punctas/20 μm, control = 16.2 ± 1.1 vs. D-PDMP = 6.4 ± 0.4, p \u3c 0.001). Interestingly, membrane perforation with Aβ occurred with a slower time course when the GM1 content was diminished (time to establish perforated configuration (TEPC) (min): control = 7.8 ± 2 vs. low GM1 = 12.1 ± 0.5, p \u3c 0.01), suggesting that the presence of GM1 in the membrane can modulate the distribution and the membrane perforation by Aβ. On the other hand, increasing GM1 facilitated the membrane perforation (TEPC: control = 7.8 ± 2 vs. GM1 = 6.2 ± 1 min, p \u3c 0.05). Additionally, using Cholera Toxin Subunit-B (CTB) to block the interaction of Aβ with GM1 attenuated membrane perforation significantly. Furthermore, pretreatment with CTB decreased the membrane association of Aβ (fluorescent-punctas/20 μm, Aβ: control = 14.8 ± 2.5 vs. CTB = 8 ± 1.4, p \u3c 0.05), suggesting that GM1 also plays a role in both association of Aβ with the membrane and in perforation. In addition, blockade of the Aβ association with CTB inhibited synaptotoxicity. Taken together, our results strongly suggest that membrane lipid composition can affect the ability of Aβ to associate and subsequently perforate the plasma membrane thereby modulating its neurotoxicity in hippocampal neurons

Structure of Compact Stars in R-squared Palatini Gravity

We analyse configurations of compact stars in the so-called R-squared gravity in the Palatini formalism. Using a realistic equation of state we show that the mass-radius configurations are lighter than their counterparts in General Relativity. We also obtain the internal profiles, which run in strong correlation with the derivatives of the equation of state, leading to regions where the mass parameter decreases with the radial coordinate in a counter-intuitive way. In order to analyse such correlation, we introduce a parametrisation of the equation of state given by multiple polytropes, which allows us to explicitly control its derivatives. We show that, even in a limiting case where hard phase transitions in matter are allowed, the internal profile of the mass parameter still presents strange features and the calculated M-R configurations also yield NSs lighter than those obtained in General Relativity.Comment: 9 pages, 5 figures. Accepted for publication in General Relativity and Gravitatio

Lifetime Measurement of the 8s Level in Francium

We measure the lifetime of the 8s level on a magneto-optically trapped sample of ^{210}Fr atoms with time-correlated single-photon counting. The 7P_{1/2} state serves as the resonant intermediate level for two-photon excitation of the 8s level completed with a 1300 nm laser. Analysis of the fluorescence decay through the the 7P_{3/2} level gives 53.30 +- 0.44 ns for the 8s level lifetime.Comment: 4 pages, 4 figure