Comment on "Oxygen as a Site Specific Probe of the Structure of Water and Oxide Materials", PRL 107, 144501 (2011)

A recent paper by Zeidler et al. (PRL 107, 144501 (2011)) describes a neutron scattering experiment on water in which oxygen isotope substitution is successfully achieved for the first time. Differences between scattering patterns with different oxygen isotopes give a combination of the O-O and O-H (or O-D) structure factors, and the method elegantly minimizes some of the problematic inelasticity effects associated with neutron scattering from hydrogen. Particular conclusions of the new work are that the OH bond length in the light water molecule is about 0.005A longer than the same bond in heavy water, and that the hydrogen bond peaks in both liquids are at about the same position. Notwithstanding the substantial progress demonstrated by the new work, the comparison with our own results (PRL, 101, 065502 (2008)) by Zeidler et al. is in our opinion misleading.Comment: 2 pages, 1 figure

Factorization is not violated

We show that existing proofs of factorization imply the cancellation of certain multiladder contributions that Gotsman, Levin, and Maor had suggested would invalidate the basic factorization theorem in QCD. No modifications of the original argument are necessary, although the details of the example offer useful insight into the mechanisms of factorization.Comment: 11 pages including 10 figure

Determination of the urinary aglycone metabolites of vitamin K by HPLC with redox-mode electrochemical detection

We describe a method for the determination of the two major urinary metabolites of vitamin K as the methyl esters of their agyclone structures, 2-methyl-3-(3-3-carboxymethylpropyl)-1,4-naphthoquinone (5C-side-chain metabolite) and 2-methyl-3-(5-carboxy-3-methyl-2-pentenyl)-1,4-naphthoquinone (7C-side-chain metabolite), by HPLC with electrochemical detection (ECD) in the redox mode. Urinary salts were removed by reversed-phase (C18) solid phase extraction (SPE) and the predominately conjugated vitamin K metabolites hydrolysed with methanolic HCl. The resultant carboxylic acid aglycones were quantitatively methylated with diazomethane and fractionated by normal-phase (silica) SPE. Final analysis was by reversed-phase (C18) HPLC with a methanol-aqueous mobile phase. Metabolites were detected by amperometric, oxidative ECD of their quinol forms, which were generated by post-column coulometric reduction at an upstream electrode. The assay gave excellent linearity (r2 typically = 0.999) and high sensitivity with an on-column detection limit of <3.5 fmol (<1pg). The inter-assay precision was typically 10%. Metabolite recovery was compared to that of an internal standard (2-methyl-3-(7'-carboxy-heptyl)-1,4-naphthoquinone), added to urine samples just before analysis. Using this methodology we confirmed that the 5C- and 7C-metabolite were major catabolites of both phylloquinone (vitamin K1) and menaquinones (vitamin K2) in humans. We propose that the measurement of urinary vitamin K metabolite excretion is a candidate non-invasive marker of total vitamin K status

An Experimental Investigation of the Structural Properties of High Modulus Aluminium Alloy

The purpose of this report is to give the results of an experimental investigation of the structural properties of high modulus aluminium alloy. The tests carried out consisted of tension, compression, hardness, bending and compression panel investigations. It was found that high modulus material is difficult to form and very prone to cracking on failure. Thus although the material has a definite structural application, in view of the forming and cracking problems it is doubtful whether further development is worthwhile

A Report Card on the Economic Literacy of U.S. High School Students

In the 1980\u27s, assessment and critique of American education has taken center stage. A large segment of the public is upset with the educational achievement of precollege students in several content areas. Economics should now be added to the list of failing subjects because the results of our study show a poor performance by many high school students in their knowledge of basic economic concepts. The study is-based on a large, national sample of students who took the second edition of the Test of Economic Literacy (TEL) (Soper-Walstad, 1987). The TEL is a nationally normed and standardized test of the basic economic understanding of students in eleventh and twelfth grades, consisting of two forms of 46 multiple choice questions. The test questions were based on A Framework for Teaching the Basic Concepts (Phillip Saunders et al., 1984). This content guide describes 22 basic economic concepts in four concept clusters- fundamental, microeconomic, macroeconomic, and international- that should be taught in secondary schools to enable students, by the time they graduate from high school, to understand enough economics to make reasoned judgments about economic questions (p. 1)

A Report Card on the Economic Literacy of U.S. High School Students

In the 1980\u27s, assessment and critique of American education has taken center stage. A large segment of the public is upset with the educational achievement of precollege students in several content areas. Economics should now be added to the list of failing subjects because the results of our study show a poor performance by many high school students in their knowledge of basic economic concepts. The study is-based on a large, national sample of students who took the second edition of the Test of Economic Literacy (TEL) (Soper-Walstad, 1987). The TEL is a nationally normed and standardized test of the basic economic understanding of students in eleventh and twelfth grades, consisting of two forms of 46 multiple choice questions. The test questions were based on A Framework for Teaching the Basic Concepts (Phillip Saunders et al., 1984). This content guide describes 22 basic economic concepts in four concept clusters- fundamental, microeconomic, macroeconomic, and international- that should be taught in secondary schools to enable students, by the time they graduate from high school, to understand enough economics to make reasoned judgments about economic questions (p. 1)