Molecular bases for unity and diversity in organic evolution

The origin of biological information has been ascribed at various times to DNA, RNA, or protein. The origin of nucleic acids without the action of prior informed protein has not been supported by plausible experiments, although such possibilities have been examined. The behavior of thermal proteins and of the microspheres selfassembled therefrom explain the origin of the first cells, the first membrane, the first reproduction cycle, ancient metabolism including ATP-aided synthesis of peptides and polynucleotides, growth, bioelectricity, and polybiofunctionality in general

Design and performance evaluation of small, two- and four-stage depressed collectors for a 4.8 to 9.6 GHz high-performance traveling wave tube

A program to improve the efficiency of traveling wave tubes (TWT's) for use in electronic countermeasure (ECM) systems by applying multistage depressed collector (MDC) and spent beam refocusing techniques is studied. Three dimensional electron trajectories are computed through-out the slow wave structure of the TWT, the spent beam refocuser, and the depressed collector. Both TWT and MDC performances are analytically evaluated

Amino acids precursors in lunar finds

The consistent pattern is discussed of amino acids found in lunar dust from Apollo missions. The evidence indicates that compounds yielding amino acids were implanted into the surface of the moon by the solar wind, and the kind and amounts of amino acids found on the moon are closely similar to those found in meteorites. It is concluded that there is a common cosmochemical pattern for the moom and meteorites, and this offers evidence of a common course of cosmochemical reactions for carbon

Association between urinary sodium, creatinine, albumin, and long term survival in chronic kidney disease

Dietary sodium intake is associated with hypertension and cardiovascular risk in the general population. In patients with chronic kidney disease, sodium intake has been associated with progressive renal disease, but not independently of proteinuria. We studied the relationship between urinary sodium excretion and urinary sodium:creatinine ratio and mortality or requirement for renal replacement therapy in chronic kidney disease. Adults attending a renal clinic who had at least one 24-hour urinary sodium measurement were identified. 24-hour urinary sodium measures were collected and urinary sodium:creatinine ratio calculated. Time to renal replacement therapy or death was recorded. 423 patients were identified with mean estimated glomerular filtration rate of 48ml/min/1.73m<sup>2</sup>. 90 patients required renal replacement therapy and 102 patients died. Mean slope decline in estimated glomerular filtration rate was -2.8ml/min/1.73m<sup>2</sup>/year. Median follow-up was 8.5 years. Patients who died or required renal replacement therapy had significantly higher urinary sodium excretion and urinary sodium:creatinine but the association with these parameters and poor outcome was not independent of renal function, age and albuminuria. When stratified by albuminuria, urinary sodium:creatinine was a significant cumulative additional risk for mortality, even in patients with low level albuminuria. There was no association between low urinary sodium and risk, as observed in some studies. This study demonstrates an association between urinary sodium excretion and mortality in chronic kidney disease, with a cumulative relationship between sodium excretion, albuminuria and reduced survival. These data support reducing dietary sodium intake in chronic kidney disease but further study is required to determine the target sodium intake

Does Taping of the Annular Pulleys of the Fingers Improve Grip Strength in Climbers?

Indoor sport climbing will debut as a new Olympic discipline at the 2020 summer games in Tokyo. The annular pulleys of the fingers are the most commonly reported injured structure in climbing. There are five annular pulleys within each finger and referred to as the A1, A2, A3, A4 and A5. The A2 and A4 structurally maintain the integrity of the flexor tendon system due to their direct attachment to the underlying bone. The A2 is the largest pulley and capable of withstanding up to 400 newton of force. Anecdotal evidence suggests some climbers apply athletic tape to the fingers both as a prophylactic measure to prevent annular pulley injury and to increase their grip strength capability. Grip refers to the method by which the climber holds the climbing surface to facilitate movement. The type of grip the climber uses largely depends on the size and shape of the available hand-holds, the climber’s body orientation in relation to the climbing surface and the strength of the climber. A common type of grip used in climbing is the closed crimp position. In this position the proximal interphalangeal joint is flexed at approximately 100° and the distal interphalangeal joint is hyperextended at approximately 210°. The distal palmer surface of the index, middle and ring fingers are normally in contact with the surface and the thumb often placed over the dorsal surface of the index finger to generate more force. The aim of the study was to investigate if taping the fingers increased crimp grip strength in uninjured climbers. Following ethical approval by the Leeds Beckett University research ethics committee, 50 active climbers (25 male, 25 female) were recruited. Using a within subject repeated measures design, a Jamar plus digital dynamometer was used to measure crimp grip strength (3 trial mean, dominant and non-dominant hand, tape and no-tape). The order of conditions was randomised and each participant performed each grip. The tape condition involved applying a 10cm piece of 1” Lewis-Plast zinc oxide tape to the proximal interphalangeal joint of the index, middle and ring fingers using the H-tape method. There was no statistically significant difference (p = 0.922, paired t-test) in crimp grip strength between tape (24.03 ± 6.9kg) and no tape (23.99 ± 7.2kg) conditions. Taping the annular pulleys did not increase crimp grip strength as measured using hand held dynamometry in uninjured climbers

Effect of Piezo Electric Oscillations on X-Ray Patterns of Quartz

Experiments have been made to determine the amplitude of vibration of the atoms in a quartz lattice due to piezo electric oscillations. A series of Laue X-ray patterns have been made of quartz plates cut at various angles to the electric axes. Very marked intensity differences are apparent between the patterns made with the plates oscillating and not oscillating

Renormalization Group Study of the soliton mass on the (lambda Phi^4)_{1+1} lattice model

We compute, on the $(\lambda \Phi^4)_{1+1}$ model on the lattice, the soliton mass by means of two very different numerical methods. First, we make use of a ``creation operator'' formalism, measuring the decay of a certain correlation function. On the other hand we measure the shift of the vacuum energy between the symmetric and the antiperiodic systems. The obtained results are fully compatible. We compute the continuum limit of the mass from the perturbative Renormalization Group equations. Special attention is paid to ensure that we are working on the scaling region, where physical quantities remain unchanged along any Renormalization Group Trajectory. We compare the continuum value of the soliton mass with its perturbative value up to one loop calculation. Both quantities show a quite satisfactory agreement. The first is slightly bigger than the perturbative one; this may be due to the contributions of higher order corrections.Comment: 19 pages, preprint DFTUZ/93/0

On the η\eta and η′\eta' Photoproduction Beam Asymmetry at High Energies

We show that, in the Regge limit, beam asymmetries in $\eta$ and $\eta'$ photoproduction are sensitive to hidden strangeness components. Under reasonable assumptions about the couplings we estimate the contribution of the $\phi$ Regge pole, which is expected to be the dominant hidden strangeness contribution. The ratio of the asymmetries in $\eta'$ and $\eta$ production is estimated to be close to unity in the forward region $0 < -t/\text{GeV}^2 \leq 1$ at the photon energy $E_\text{lab} = 9$~GeV, relevant for the upcoming measurements at Jefferson Lab.Comment: 9 pages, 4 figure

A Positivity Theorem for Gravitational Tension in Brane Spacetimes

We study transverse asymptotically flat spacetimes without horizons that arise from brane matter sources. We assume that asymptotically there is a spatial translation Killing vector that is tangent to the brane. Such spacetimes are characterized by a tension, analogous to the ADM mass, which is a gravitational charge associated with the asymptotic spatial translation Killing vector. Using spinor techniques, we prove that the purely gravitational contribution to the spacetime tension is positive definite.Comment: 8+1 page