Viscoelastic properties of human and bovine articular cartilage : a comparison of frequency-dependent trends

Acknowledgments The authors would like to thank Spencer C. Barnes and Hamid Sadeghi for assistance during experimentation. We would also like to thank patients donating tissue and the surgeons collecting these. Funding The equipment used in this study was funded by Arthritis Research UK (Grant number H0671). We are grateful to Arthritis Research UK for the award of a PhD studentship to Anna A. Cederlund (Grant number 19971). Arthritis Research UK had no role in the design of the study and collection, analysis and interpretation of data and in writing the manuscript.Peer reviewedPublisher PD

Cross-Border Valuation: The International Cost of Equity Capital

How does a firm in one country evaluate an investment in a firm in another country, or how does it evaluate a foreign project that the firm itself is undertaking? The firm must estimate future free cash flows just as in a domestic project, but choosing an appropriate discount rate is a particular challenge. This study examines the determinants of the discount rate for an international acquisition or project by examining the sources of risk in an international setting. These risks include stock-market price risk measured with various versions of the capital asset pricing model, as well as exchange rate risk and political risk. To measure stock market risk, both segmented and integrated models of the world equity markets are considered. The emphasis of the study is on some of the practical aspects of estimation, particular for markets where no comparable investments exist on which to base estimates of risk premiums. To show how each of these risks might be measured, the study reports estimates for a representative French firm, Thals. The estimates range widely depending on whether or not the equity market is globally integrated.

Renormalization factor and effective mass of the two-dimensional electron gas

We calculate the momentum distribution of the Fermi liquid phase of the homogeneous, two-dimensional electron gas. We show that, close to the Fermi surface, the momentum distribution of a finite system with $N$ electrons approaches its thermodynamic limit slowly, with leading order corrections scaling as $N^{-1/4}$. These corrections dominate the extrapolation of the renormalization factor, $Z$, and the single particle effective mass, $m^*$, to the infinite system size. We show how convergence can be improved analytically. In the range $1 \le r_s \le 10$, we get a lower renormalization factor $Z$ and a higher effective mass, $m^*>m$, compared to the perturbative RPA values.Comment: 4 pages, 3 figure

Attrition-enhanced total resolution leads to homochiral families of amino acid derivatives

The total resolution of five structurally similar racemizable amino acid derivatives, three of which have racemic crystal structures, was performed simultaneously. By enantioselective incorporation in an amino acid derivative that forms a conglomerate the other four were deracemized on attrition-induced grinding. The outcome of the resolution was random (R) or (S), but all compounds had the same absolute configuration and high enantiomeric purities.

Lack of a response of the sub-tropical rodent (Saccostomus campestris) to a secondary plant compound, 6-methoxybenzoxazolinone — consequences for reproductive strategy

A potential strategy for southern African small mammals to maximise reproductive success is to cue breeding activity to rainfall and subsequent vegetative growth via a secondary plant compound such as 6-methoxybenzoxazolinone (6MBOA). This study investigated whether the sub-tropical rodent Saccostomus campestris utilised this compound to enhance reproductive activity. 6MBOA or control vehicle were injected into adult females and into peri-pubertal females under long day (LD) and short day (SD) photoperiods (adults n = 6 to 8: peri-pubertals n = 5 to 10/treatment). There was no significant effect of 6MBOA or photoperiod on uterine or ovarian masses nor on ovarian development in sacrificed animals, nor on age at vaginal opening of peri-pubertals It was concluded that 6MBOA is not a major stimulant of reproduction in this species. Rather, we propose that seasonal breeding occurs in response to multiple environmental cues. This reproductive strategy and omnivory permit

Extending Syncom 3\u27s Orbital Life Over the Pacific

Syncom 3, launched in August 1964, was the first satellite to be maneuvered to a nearstationary orbit. It is presently functioning as an essential communication link between Hawaii and the Far East, As long as the satellite remains within mutual visibility of these areas, this link will continue to exist. Ironically, the by-product of an unwanted process, namely, gas resulting from decomposition of the propellant (hydrogen peroxide) which was originally intended to provide orbital control, is now being used to maintain this link. If the satellite orbit were not controllable, Syncorn 3 would drift out of the mutual visibility longitude band as a result of forces exerted by the earth\u27s triaxiality, The unstable equilibrium longitude in the Pacific, computed to be at 162.4 °E, lies within this band. Near this point, the control velocity requirements are small, so that minimal control capability, such as is available from the gas, could extend Syncom 3\u27s orbital life for as much as 10 years. This is unlikely, however, because of the degraded condition of the batteries which are essential for operation of the control jets. The satellite on its present drift trajectory should remain visible from Hawaii until early 1969. Longitudinal control of Syncom 3 in the vicinity of the Pacific equilibrium longitude has now been accomplished with gas for approximately 1.5 years. The specific impulse observed is approximately 57.1 seconds. The mass flow rates observed have resulted in velocity increments of about 0.005 fps per pulse, Such high resolution is required to maintain the satellite position close to but west of the equilibrium longitude. This constraint is based on the increased, visibility time for westerly drift in case of complete loss or depletion of control capability. Since the batteries are weak and gas leaks are to be expected in a system not originally designed for use of gas, such a constraint is reasonable

An Empirical Decomposition of Near-IR Emission into Galactic and Extragalactic Components

We decompose the COBE/DIRBE observations of the near-IR sky brightness (minus zodiacal light) into Galactic stellar and interstellar medium (ISM) components and an extragalactic background. This empirical procedure allows us to estimate the 4.9 micron cosmic infrared background (CIB) as a function of the CIB intensity at shorter wavelengths. A weak indication of a rising CIB intensity at wavelengths > 3.5 micron hints at interesting astrophysics in the CIB spectrum, or warns that the foreground zodiacal emission may be incompletely subtracted. Subtraction of only the stellar component from the zodiacal-light-subtracted all-sky map reveals the clearest 3.5 micron ISM emission map, which is found to be tightly correlated with the ISM emission at far-IR wavelengths.Comment: 10 pages. 10 JPEG and PNG figures. Uses emulateapj5.sty. To appear in 2003, ApJ, 585, 000 (March 1, 2003

Bostonia: The Boston University Alumni Magazine. Volume 34

Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

An exploration of bias in meta-analysis: the case of technology integration research in higher education

© 2014, Springer Science+Business Media New York. This article contains a second-order meta-analysis and an exploration of bias in the technology integration literature in higher education. Thirteen meta-analyses, dated from 2000 to 2014 were selected to be included based on the questions asked and the presence of adequate statistical information to conduct a quantitative synthesis. The weighted random effects average was g++ = 0.393, p \u3c .000. The article goes on to report an assessment of the methodological quality of the thirteen studies based on Cooper’s (Research synthesis and meta-analysis: a step-by-step approach. Sage, Thousand Oaks, 2010) seven stages in the development of a meta-analysis. Two meta-analyses were found to have five out of seven stages where methodological flaws could potentially create biased results. Five meta-analyses contained two flawed stages and one contained one flawed stage. Four of the stages where methodological flaws can create bias are described in detail. The final section attempts to determine how much influence the methodological flaws exerted on the results of the second-order meta-analysis