Microscopes and computers combined for analysis of chromosomes

Scanning machine CHLOE, developed for photographic use, is combined with a digital computer to obtain quantitative and statistically significant data on chromosome shapes, distribution, density, and pairing. CHLOE permits data acquisition about a chromosome complement to be obtained two times faster than by manual pairing

Capital Punishment: The Great American Paradox

On June 6, 1944, American forces landed on Omaha and Utah beaches as part of the Normandy invasion that had as its objective the liberation of occupied Europe from the tyranny of the Nazi Occupation. This was America at its finest hour. This was not a professional army, but an army consisting of young men who had been drafted or had enlisted after Pearl Harbor. The young men came from all walks of life: farmers, teachers, family members, mechanics, truck drivers and the rest, with the sole objective to make the world safe again from the atrocities of the Axis Powers. They were part of America’s Greatest Generation. Ten months later the war was over; Germany had been defeated. Europe owed America a debt of gratitude. American blood had been spilled to drive the Hun into submission. This author has been to the American Cemetery on the cliffs of Normandy overlooking the English Channel. There, in neat rows, are hundreds of small crosses and Stars of David marking the graves of those who died in this cause for freedom. It was a very emotional experience. Indeed, if one goes there and does not shed a tear of emotion, that person should check his pulse for signs of life. On June 16, 1944, ten days after the invasion, as American troops were slowly advancing along the hedge rows of Normandy, fourteen-year-old George Stinney, Jr. was executed for the killing of two white girls. He was tried in the Jim Crow South. After a two-hour trial and a ten-minute deliberation, the young boy was convicted of murder by an all-white jury and sentenced to die by electrocution. His lawyer elected not to appeal. The main evidence against Stinney was his alleged confession that was reportedly made without the presence of his lawyer or parents. There was no written record of the confession. Many young Americans died on June 16, 1944, in defense of the ideals for which this country supposedly stands. On the same date, as these unsung heroes were battling the Nazi war machine, Stinney, who was barely five feet tall and weighed just more than 90 pounds, was led to the electric chair. “The electric chair’s straps were too big for his frail body. Newspapers at the time reported he had to sit on books to reach the headpiece. And when the switch was flipped, the convulsions knocked down the large mask, exposing his tearful face to the crowd.” It would take seven decades after this brutal execution to exonerate him. For George Stinney, the American ideal had no meaning. He died solely as a result of the color of his skin and the prejudices of the time. Unspeakable horrors occurred on the battle fields of France and in the court house in Alcolu, South Carolina on that date in June 1944, only ten days after the invasion. This is but one example of the great American Paradox. We kill in the name of justice, while portraying ourselves as a leader of the civilized world in the effort to protect basic human rights. It is time for this masquerade to stop. We should finally accept what most of the civilized world has long ago acknowledged: capital punishment is an anathema to any country that purports to call itself civilized. It is time to separate ourselves from the totalitarian regimes of our world. We should not walk in lockstep with those nations who view executions as justice

Deterministic Secure Communications using Two-Mode Squeezed States

We propose a scheme for quantum cryptography that uses the squeezing phase of a two-mode squeezed state to transmit information securely between two parties. The basic principle behind this scheme is the fact that each mode of the squeezed field by itself does not contain any information regarding the squeezing phase. The squeezing phase can only be obtained through a joint measurement of the two modes. This, combined with the fact that it is possible to perform remote squeezing measurements, makes it possible to implement a secure quantum communication scheme in which a deterministic signal can be transmitted directly between two parties while the encryption is done automatically by the quantum correlations present in the two-mode squeezed state.Comment: 10 pages, 4 figure

Static and dynamic properties of Single-Chain Magnets with sharp and broad domain walls

We discuss time-quantified Monte-Carlo simulations on classical spin chains with uniaxial anisotropy in relation to static calculations. Depending on the thickness of domain walls, controlled by the relative strength of the exchange and magnetic anisotropy energy, we found two distinct regimes in which both the static and dynamic behavior are different. For broad domain walls, the interplay between localized excitations and spin waves turns out to be crucial at finite temperature. As a consequence, a different protocol should be followed in the experimental characterization of slow-relaxing spin chains with broad domain walls with respect to the usual Ising limit.Comment: 18 pages, 13 figures, to be published in Phys. Rev.

Secondary ion mass spectrometry and x-ray absorption near-edge structure spectroscopy of isotopically anomalous organic matter from CR1 chondrites GRO 95577

We located interstellar organics from a CR1 chondrite with NanoSIMS and analyzed FIB-extracted sections with XANES. D-rich material appears not associated with a functional group, whereas 15N-rich matter shows some affinity to nitrile functionality

Exact results and scaling properties of small-world networks

We study the distribution function for minimal paths in small-world networks. Using properties of this distribution function, we derive analytic results which greatly simplify the numerical calculation of the average minimal distance, $\bar{\ell}$, and its variance, $\sigma^2$. We also discuss the scaling properties of the distribution function. Finally, we study the limit of large system sizes and obtain some analytic results.Comment: RevTeX, 4 pages, 5 figures included. Minor corrections and addition

Size matters: the value of small populations for wintering waterbirds

Protecting systematically selected areas of land is a major step towards biodiversity conservation worldwide. Indeed, the identification and designation of protected areas more often than not forms a core component of both national and international conservation policies. In this paper we provide an overview of those Special Protection Areas and Ramsar Sites that have been classified in Great Britain as of 1998/99 for a selection of wintering waterbird species, using bird count data from the Wetland Bird Survey. The performance of this network of sites is remarkable, particularly in comparison with published analyses of networks elsewhere in the world. Nevertheless, the current site-based approach, whilst having the great benefit of simplicity, is deliberately biased towards aggregating species at the expense of the more dispersed distribution species. To ensure that the network continues successfully to protect nationally and internationally important waterbird populations, efforts now need to concentrate on the derivation of species-specific representation targets and, in particular, the ways in which these can be incorporated into the site selection process. Although these analyses concern the performance of protected areas for waterbirds in Great Britain, the results have wide-ranging importance for conservation planning in general and the design of protected area networks

Photochemistry in the arctic free troposphere: NOx budget and the role of odd nitrogen reservoir recycling

The budget of nitrogen oxides (NOx) in the arctic free troposphere is calculated with a constrained photochemical box model using aircraft observations from the Tropospheric O3 Production about the Spring Equinox (TOPSE) campaign between February and May. Peroxyacetic nitric anhydride (PAN) was observed to be the dominant odd nitrogen species (NOy) in the arctic free troposphere and showed a pronounced seasonal increase in mixing ratio. When constrained to observed acetaldehyde (CH3CHO) mixing ratios, the box model calculates unrealistically large net NOx losses due to PAN formation (62pptv/day for May, 1-3km). Thus, given our current understanding of atmospheric chemistry, these results cast doubt on the robustness of the CH3CHO observations during TOPSE. When CH3CHO was calculated to steady state in the box model, the net NOx loss to PAN was of comparable magnitude to the net NOx loss to HNO3 (NO2 reaction with OH) for spring conditions. During the winter, net NOx loss due to N2O5 hydrolysis dominates other NOx loss processes and is near saturation with respect to further increases in aerosol surface area concentration. NOx loss due to N2O5 hydrolysis is sensitive to latitude and month due to changes in diurnal photolysis (sharp day-night transitions in winter to continuous sun in spring for the arctic). Near NOx sources, HNO4 is a net sink for NOx; however, for more aged air masses HNO4 is a net source for NOx, largely countering the NOx loss to PAN, N2O5 and HNO3. Overall, HNO4 chemistry impacts the timing of NOx decay and O3 production; however, the cumulative impact on O3 and NOx mixing ratios after a 20-day trajectory is minimal. © 2003 Elsevier Science Ltd. All rights reserved

Dimensional Crossover in the Effective Second Harmonic Generation of Films of Random Dielectrics

The effective nonlinear response of films of random composites consisting of a binary composite with nonlinear particles randomly embedded in a linear host is theoretically and numerically studied. A theoretical expression for the effective second harmonic generation susceptibility, incorporating the thickness of the film, is obtained by combining a modified effective-medium approximation with the general expression for the effective second harmonic generation susceptibility in a composite. The validity of the thoretical results is tested against results obtained by numerical simulations on random resistor networks. Numerical results are found to be well described by our theory. The result implies that the effective-medium approximation provides a convenient way for the estimation of the nonlinear response in films of random dielectrics.Comment: 9 pages, 2 figures; accepted for publication in Phys. Rev.