A Collection of Mathematical and Statistical Routines in FORTRAN 90

The purpose of this brief note is to bring to the attention of readers a collection of Fortran routines which may be useful to readers of this journal. The author collected the routines over many years, starting while acting as a statistical consultant in CSIRO (Commonwealth Scientific and Industrial Research Organization, Australia). Though most statistical analysis is now done using statistical packages, code in Fortran and other languages is useful for instance when developing new tests or estimates, or for finding maximum likelihood estimates in complex cases.

A Collection of Mathematical and Statistical Routines in FORTRAN 90

The purpose of this brief note is to bring to the attention of readers a collection of Fortran routines which may be useful to readers of this journal. The author collected the routines over many years, starting while acting as a statistical consultant in CSIRO (Commonwealth Scientific and Industrial Research Organization, Australia). Though most statistical analysis is now done using statistical packages, code in Fortran and other languages is useful for instance when developing new tests or estimates, or for finding maximum likelihood estimates in complex cases

Spatial dependence of gain nonlinearities in InGaAs semiconductor optical amplifier

Counter-propagating sub-picosecond pulses are used to monitor gain saturation along the waveguide of an InGaAs superlattice semiconductor optical amplifier at 1550 nm wavelength. The functional form of the spatial dependence of gain saturation is found to depend on pulse energy. These observations are interpreted by combining the optical nonlinearities associated with interband carrier dynamics and carrier heating together and their respective time constants. We show that the results are consistent with the predictions of a propagation model. Implications for all-optical switching, particularly in the limit of full saturation across the whole amplifier, are discussed. (c) 2005 American Institute of Physics.</p

Room temperature electron spin relaxation in GaInNAs multiple quantum wells at 1.3 mu m

The authors report a direct measurement of electron spin relaxation in GaInNAs semiconductor multiple quantum wells at room temperature. Multiple quantum wells of widths 5.8, 7, and 8 nm exhibiting excitonic absorption around 1.3 mu m have been studied. Spin relaxation times were found to increase with well width in the range of 77-133 ps. The spin relaxation time dependence on first electron confinement energy suggests the Elliot-Yafet mechanism [A. Tackeuchi , Physica B 272, 318 (1999)] as the dominant relaxation process. (c) 2006 American Institute of Physics.</p

Tension Tests on Drilled Micropiles in a Stiff Clay

A series of 20 small diameter drilled and grouted micropiles were installed at three different depths in a stiff surficial clay crust at the National Geotechnical Experimentation Site in Amherst, Massachusetts. A detailed site characterization program was performed to evaluate· the soil characteristics in the crust. Three different sizes of micropiles ranging in diameter from 76 mm to 152 mm and having lengths from 1.52 m to 4.57 m were installed vertically at the site using both continuous flight augers and hand auger techniques. Concrete was placed in the open holes using gravity free-tall. After allowing the concrete to cure for a period of 30 days, tension tests to failure were conducted on each of the micropiles. Following initial tests, some of the micropiles were retested after a resting period of one year to evaluate the recovery in tension capacity. This paper presents a description of the soil characteristics at the site including both laboratory and field test results and a description of the methods used to construct and test the micropiles. A comparison is made of the ultimate capacity obtained from the tests. The influence of drilling technique and the effect of reloading on the measured capacity are discussed

A predicted dimer-based polymorph of 10,11-dihydrocarbamazepine (Form IV)

A novel polymorph of 10,11-dihydrocarbamazepine (form IV), which had been predicted to be thermodynamically feasible, was obtained from the vapour phase and displays an R22(8) hydrogen bonded dimer motif in contrast to the catemeric motifs in forms I–III

Measurement of the B Semileptonic Branching Fraction with Lepton Tags

We have used the CLEO II detector and 2.06fb^(-1) of ϒ(4S) data to measure the B-meson semileptonic branching fraction. The B→Xeν momentum spectrum was obtained over nearly the full momentum range by using charge and kinematic correlations in events with a high-momentum lepton tag and an additional electron. We find B(B→Xeν) = (10.49±0.17±0.43)%, with overall systematic uncertainties less than those of untagged single-lepton measurements. We use this result to calculate the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element V_(cb) and to set an upper limit on the fraction of ϒ(4S) decays to final states other than BB̅

Ultrafast electroabsorption dynamics in an InAs quantum dot saturable absorber at 1.3 mu m

The authors report a direct measurement of the absorption dynamics in an InAs p-i-n ridge waveguide quantum dot modulator. The carrier escape mechanisms are investigated via subpicosecond pump-probe measurements at room temperature, under reverse bias conditions. The optical pulses employed are degenerate in wavelength with the quantum dot ground state transition at 1.28 mu m. The absorption change recovers with characteristic times ranging from 62 ps (0 V) to similar to 700 fs (-10 V), showing a decrease of nearly two orders of magnitude. The authors show that at low applied fields, this recovery is attributed to thermionic emission while for higher applied fields, tunneling becomes the dominant mechanism. (c) 2006 American Institute of Physics.</p

Measurement of B(D^0 → K^-π^+) Using Partial Reconstruction of B̅ → D^(*+)Xℓ^-ν̅

We present a measurement of the absolute branching fraction for D^0→K^-π^+ using the reconstruction of the decay chain B̅ →D^(*+)Xℓ^-ν̅ , D^(*+)→D^0π^+ where only the lepton and the low-momentum pion from the D^(*+) are detected. With data collected by the CLEO II detector at the Cornell Electron Storage Ring, we have determined B(D^0→K^-π^+) = [3.81±0.15(stat)±0.16(syst)]%