DNA Renaturation at the Water-Phenol Interface

We study DNA adsorption and renaturation in a water-phenol two-phase system, with or without shaking. In very dilute solutions, single-stranded DNA is adsorbed at the interface in a salt-dependent manner. At high salt concentrations the adsorption is irreversible. The adsorption of the single-stranded DNA is specific to phenol and relies on stacking and hydrogen bonding. We establish the interfacial nature of a DNA renaturation at a high salt concentration. In the absence of shaking, this reaction involves an efficient surface diffusion of the single-stranded DNA chains. In the presence of a vigorous shaking, the bimolecular rate of the reaction exceeds the Smoluchowski limit for a three-dimensional diffusion-controlled reaction. DNA renaturation in these conditions is known as the Phenol Emulsion Reassociation Technique or PERT. Our results establish the interfacial nature of PERT. A comparison of this interfacial reaction with other approaches shows that PERT is the most efficient technique and reveals similarities between PERT and the renaturation performed by single-stranded nucleic acid binding proteins. Our results lead to a better understanding of the partitioning of nucleic acids in two-phase systems, and should help design improved extraction procedures for damaged nucleic acids. We present arguments in favor of a role of phenol and water-phenol interface in prebiotic chemistry. The most efficient renaturation reactions (in the presence of condensing agents or with PERT) occur in heterogeneous systems. This reveals the limitations of homogeneous approaches to the biochemistry of nucleic acids. We propose a heterogeneous approach to overcome the limitations of the homogeneous viewpoint

Politics vs Market

As China's demand for energy grows, so does its dependence on imported oil. Currently, over 40 percent of China's total oil consumption derives from foreign sources making a supply disruption of the oil import routes an unthinkable blow to its national economy. Oil supply security has thus become the contemporary imperative and has raised a number of critical questions. Will oil be used as a weapon against China by exporters? Will a shortage or undersupply of oil resources lead to energy wars between China and other major importers such as the United States and Japan? Politicians and scholars must think hard about these critical issues

Measurement of the neutron proton spin correlation parameter Azz at forward angles

The n-p spin correlation parameter Azz was measured at an energy of 68 MeV and 7 angles in the range of 22.5° - 57.3° CM with a statistical accuracy better than 0.01. In the measured range, Azz is most semsitive to є1, the mixing parameter of the deuteron states 2S1 and 2D1. Therefore the measurement is expected to reduce significantly the uncertainties of the phases in the energy range below 100 MeV, when a new global Phase Shift Analysis (PSA) is performed. This should help to find a more accurate answer to the strength of the tensor force in the NN-interaction. The experiment was performed in the low energy area C (NEC) of the Paul Scherrer Institute )PSI) in Villigen, Switzerland

Exercises for word analysis in grade II.

Thesis (Ed.M.)--Boston University N.B.: the following pages are missing: cover page; pages 374-376 at end of text

Japan After an ‘Export Bubble’

Recent economic indicators of the performance of the Japanese economy have been weak and prognosis negative. In December Japanese industrial output contracted by 10%. In January this trend intensified. Moreover Toyota has announced 7,000 job losses and Honda a four month closure of their UK plant. Other labour market indicators and consumption related data suggest that the negative shock in the manufacturing sector is spreading gradually to the household sector. Paul Krugman has suggested that the Japanese economy is in ‘free fall’ as is world trade. This view can be linked to those who accuse Japan of relying on exports for growth and contributing to international imbalances that lie at the heart of the current financial crisis

The cluster of galaxies Abell 376

We present a dynamical analysis of the galaxy cluster Abell 376 based on a set of 73 velocities, most of them measured at Pic du Midi and Haute-Provence observatories and completed with data from the literature. Data on individual galaxies are presented and the accuracy of the determined velocities is discussed as well as some properties of the cluster. We obtained an improved mean redshift value z=0.0478^{+0.005}_{-0.006} and velocity dispersion sigma=852^{+120}_{-76}km/s. Our analysis indicates that inside a radius of 900h_{70}^{-1}kpc (15 arcmin) the cluster is well relaxed without any remarkable feature and the X-ray emission traces fairly well the galaxy distribution. A possible substructure is seen at 20 arcmin from the centre towards the Southwest direction, but is not confirmed by the velocity field. This SW clump is, however, kinematically bound to the main structure of Abell 376. A dense condensation of galaxies is detected at 46 arcmin (projected distance 2.6h_{70}^{-1}Mpc) from the centre towards the Northwest and analysis of the apparent luminosity distribution of its galaxies suggests that this clump is part of the large scale structure of Abell 376. X-ray spectroscopic analysis of ASCA data resulted in a temperature kT = 4.3+/-0.4 keV and metal abundance Z = 0.32+/-0.08 Z_solar. The velocity dispersion corresponding to this temperature using the T_X-sigma scaling relation is in agreement with the measured galaxies velocities.Comment: 11 pages, 10 figures, accepted for publication in A&

Book Review: The Importance of Being Little: What Young Children Really Need from Grownups

The Importance of Being Little: What Young Children Really Need from Grownups, by Erika Christakis. New York, NY: Penguin, 2016. 376 pp., $15.59 (hardcover)

TEMPOS: A Platform for Developing Temporal Applications on Top of Object DBMS

This paper presents TEMPOS: a set of models and languages supporting the manipulation of temporal data on top of object DBMS. The proposed models exploit object-oriented technology to meet some important, yet traditionally neglected design criteria related to legacy code migration and representation independence. Two complementary ways for accessing temporal data are offered: a query language and a visual browser. The query language, namely TempOQL, is an extension of OQL supporting the manipulation of histories regardless of their representations, through fully composable functional operators. The visual browser offers operators that facilitate several time-related interactive navigation tasks, such as studying a snapshot of a collection of objects at a given instant, or detecting and examining changes within temporal attributes and relationships. TEMPOS models and languages have been formalized both at the syntactical and the semantical level and have been implemented on top of an object DBMS. The suitability of the proposals with regard to applications' requirements has been validated through concrete case studies

Similarity and attraction effects in episodic memory judgments

In the decision-making literature, it is known that preferences between two options can be influenced in different ways by the introduction of a third option. We investigated whether such influences could be demonstrated when making decisions about qualitative aspects of episodic memories. In a baseline condition, participants were asked which of two dissimilar events they remembered more vividly: (A) a well-known Olympic victory, or (B) the death of a well-known public figure. In two further conditions, a third event was added: (C) an Olympic victory similar and competitive to A, or (D) an Olympic victory similar but inferior to A. With the addition of C, participants were less likely to choose A than B (similarity effect), whereas with the addition of D, they were more likely to choose A than B (attraction effect), suggesting that effects known in decision-making can be generalised to relative judgments about episodic memories