Funded Pensions, Labor Market Participation, and Economic Growth.

This paper analyses a model of overlapping generations in which agents who do not participate in th elabor market are unable to borrow. Thus an increase in a fully funded pension raises aggregate savings even with a fixed participation rate since private savings are not crowded out one-for-one. When labor force participation is determined endogenously, a rise in the level of fully funded pensions increases the aggregate labor supply. This in turn increases aggregate savings and growth, directly by raising per capita savings and indirectly through tax and interest rate effects.

Computer assisted molecular modeling of thymidine nucleoside analog inhibitors of HIV-1 reverse transcriptase

An active analog approach to receptor mapping was used to identify the three dimensional structural characteristics associated with a series of thymidine nucleoside analog inhibitors of HIV-1 reverse transcriptase (RT) that may be essential for their activity. Atomic substitutions at the 5 and 3\u27 positions of nucleoside analogs confer global structural and electrostatic changes that result in either increased or diminished inhibitory activity. From a structural perspective, the activity differences can be attributed to the presentation of select atoms in three dimensional motifs that are common to all active compounds and absent or distorted in inactive/poorly active compounds. The identification of these characteristics will complement more direct studies of the RT structure by providing a specific three dimensional orientation for substrate and inhibitor molecules at their receptor site. They can also serve as a three dimensional template for the screening of potentially active compounds; thus, aiding in the development and identification of new, more potent and selective inhibitor molecules. The characteristics identified are common to 15 thymidine nucleoside analog inhibitors of RT and have allowed the inference of a three dimensional map of the HIV-1 RT receptor site

Radio Galaxy Clustering at z~0.3

Radio galaxies are uniquely useful as probes of large-scale structure as their uniform identification with giant elliptical galaxies out to high redshift means that the evolution of their bias factor can be predicted. As the initial stage in a project to study large-scale structure with radio galaxies we have performed a small redshift survey, selecting 29 radio galaxies in the range 0.19<z<0.45 from a contiguous 40 square degree area of sky. We detect significant clustering within this sample. The amplitude of the two-point correlation function we measure is consistent with no evolution from the local (z<0.1) value. This is as expected in a model in which radio galaxy hosts form at high redshift and thereafter obey a continuity equation, although the signal:noise of the detection is too low to rule out other models. Larger surveys out to z~1 should reveal the structures of superclusters at intermediate redshifts and strongly constrain models for the evolution of large-scale structure.Comment: 7 pages, 3 figures, accepted by ApJ Letter

Evidence for a Spectroscopic Sequence Among SNe Ia

In this Letter we present evidence for a spectral sequence among Type Ia supernovae (SNe Ia). The sequence is based on the systematic variation of several features seen in the near-maximum light spectrum. This sequence is analogous to the recently noted photometric sequence among SNe Ia which shows a relationship between the peak brightness of a SN Ia and the shape of its light curve. In addition to the observational evidence we present a partial theoretical explanation for the sequence. This has been achieved by producing a series of non-LTE synthetic spectra in which only the effective temperature is varied. The synthetic sequence nicely reproduces most of the differences seen in the observed one and presumably corresponds to the amount of 56Ni produced in the explosion.Comment: To appear in Astrophysical Journal Letters, uuencoded, gzipped postscript file, also available from http://www.nhn.uoknor.edu/~baron

Cerebral Microbleeds in a Stroke Prevention Clinic.

The objective of this study is to assess the effectiveness of a stroke clinic in stroke prevention and progression of cerebral microbleeds (CMB). We conducted a retrospective observational study of patients who visited a stroke clinic between January 2011 and March 2017. Susceptibility-weighted imaging (SWI) MRI studies were obtained at baseline and follow-up visits to identify new infarctions and CMB progression. Patients with CMB who also underwent brain computed tomography (CT) imaging were identified and their cerebral arterial calcification was quantified to evaluate the relationship between the extent of intracranial calcification and CMB burden. A total of 64 stroke patients (mean age 73.1 ± 11.0, 47% males) had CMB on baseline and follow-up MRI studies. During a mean follow-up period of 22.6 months, four strokes occurred (4/64, 6%; 3 ischemic, 1 hemorrhagic), producing mild neurological deficit. Progression of CMB was observed in 54% of patients with two MRIs and was significantly associated with length of follow-up. Subjects with intracranial calcification score &gt; 300 cm3 had higher CMB count than those with scores &lt;300 cm3 at both baseline (12.6 ± 11.7 vs. 4.9 ± 2.2, p = 0.02) and follow-up (14.1 ± 11.8 vs. 5.6 ± 2.4, p = 0.03) MRI evaluations. Patients with CMB had a relatively benign overall clinical course. The association between CMB burden and intracranial calcification warrants further study

Crystallographic phase changes and damage thresholds of CsPbI3 microwire waveguides through continuous wave photoablation

We investigate waveguide efficiency of CsPbI3 microwire waveguides and their photodegradation over a range of continuous wave laser excitation energies and intensities. Under modest laser input intensities <1 kW cm−2 we observe a wavelength dependent efficiency of light propagation in the waveguides. At increased power densities and wavelengths of 473 nm or shorter, microwires undergo photoablation into discrete fragments. Use of diffraction-limited excitation allowed localised cleavage of the microwires with observation of transient photoluminescence from degradation products. TEM analysis of the microwires revealed transformation from the yellow δ-phase to amorphous phases in the region of the photodamage with a degraded morphology consistent with efficient thermal transfer and induced melting

The impact of motion and motion sickness on human performance aboard monohull vessels and surface effect ships: a comparative study

The primary objective of this report is to present and analyze those studies that have been conducted to determine the effects of motion and motion sickness on human performance aboard vessels at sea. To accomplish this, a comparison between the motions experienced aboard several types of monohull vessels and the simulated motions of a 2,000 tons generic surface effect ship will be made. Background information concerning motion sickness and recommendations for future studies are also presented.http://archive.org/details/impactofmotionmo00fishLieutenant, United States Coast GuardApproved for public release; distribution is unlimited

Measurement of ligand coverage on cadmium selenide nanocrystals and its influence on dielectric dependent photoluminescence intermittency

Photoluminescent quantum dots are used in a range of applications that exploit the unique size tuneable emission, light harvesting and quantum efficient properties of these semiconductor nanocrystals. However, optical instabilities such as photoluminescence intermittency, the stochastic switching between bright, emitting states and dark states, can hinder quantum dot performance. Correlations between this blinking of emission and the dielectric properties of the nanoenvironment between the quantum dot interface and host medium, suggest surface ligands play a role in modulating on-off switching rates. Here we elucidate the nature of the cadmium selenide nanocrystal surface, by combining magic angle spinning NMR and x-ray photoelectron spectroscopy to determine ligand surface densities, with molecular dynamics simulation to assess net ligand filling at the nanocrystal interface. Results support a high ligand coverage and are consistent with photoluminescence intermittency measurements that indicate a dominant contribution from surface ligand to the dielectric properties of the local quantum dot environment