Reactions of Na/plus/, K/plus/, and Ba/plus/ ions with O2, NO, and H2O molecules

Investigating ion molecule reactions of sodium, potassium, and barium ions with oxygen, nitric oxide, and water in drift tube mass spectromete

Effect of nickel in solid solution on hydrogen transport kinetics in low alloy steels

The use of low alloy steels (LAS) in H2S-containing environments in the oil and gas industry is governed by the ISO standard 15156-2 (NACE MR0175-2). One requirement, which has been disputed over the years, is that the nickel (Ni) content shall not exceed 1 wt%. This work investigated the effect of Ni in solid solution on hydrogen diffusion, solubility, and trapping in ferritic/pearlitic research-grade LAS with nominal Ni contents from 0 to 3 wt%. Hydrogen permeability experiments were carried out in a Devanathan-Stachurski setup at 15, 45 and 70 °C. The effective diffusion coefficients, calculated by the tlag method, decreased with increasing Ni content. The sub-surface hydrogen concentration in lattice and trap sites increased with increasing Ni content. There was no difference between the first and subsequent hydrogen permeation transients, suggesting that Ni in solid solution forms reversible traps. The effect of Ni in refining the microstructure may be superimposed on the effect of Ni in solid solution, and should be investigated in future work

Selective cooling of the brain in reindeer

Selective cooling of the brain during hyper-thermia has been demonstrated in several species of mammals (Baker 1979, 1982). Such cooling is achieved by heat exchange between the cooled venous blood returning from the nasal mucosa and the warmer arterial blood entering the brain via the carotid rete. Spot measurements of brain temperature (Tbr) and carotid blood temperature (TCar) were made within 1 min. of death in 40 wild reindeer (Rangifer tarandus tarandus). At Tear lower than 40.5°C Tbr was higher than T c a r. With increasing Tear above 40.5°C Tbr remained at approxima-tely 40.5°C, indicating that selective cooling of the brain had occurred

Excitonic Dynamical Franz-Keldysh Effect

The Dynamical Franz-Keldysh Effect is exposed by exploring near-bandgap absorption in the presence of intense THz electric fields. It bridges the gap between the DC Franz- Keldysh effect and multi-photon absorption and competes with the THz AC Stark Effect in shifting the energy of the excitonic resonance. A theoretical model which includes the strong THz field non-perturbatively via a non-equilibrium Green Functions technique is able to describe the Dynamical Franz-Keldysh Effect in the presence of excitonic absorption.Comment: 4 pages in revtex with 5 figures included using epsf. Submitted to Physical Review Letter

Quasienergy Spectroscopy of Excitons

We theoretically study nonlinear optics of excitons under intense THz irradiation. In particular, the linear near infrared absorption and resonantly enhanced nonlinear sideband generation are described. We predict a rich structure in the spectra which can be interpreted in terms of the quasienergy spectrum of the exciton, via a remarkably transparent expression for the susceptibility, and show that the effects of strongly avoided quasienergy crossings manifest themselves directly, both in the absorption and transmitted sidebands.Comment: 4 pages RevTex, 3 eps figs included, as publishe

No alignment of cattle along geomagnetic field lines found

This paper presents a study of the body orientation of domestic cattle on free pastures in several European states, based on Google satellite photographs. In sum, 232 herds with 3412 individuals were evaluated. Two independent groups participated in our study and came to the same conclusion that, in contradiction to the recent findings of other researchers, no alignment of the animals and of their herds along geomagnetic field lines could be found. Several possible reasons for this discrepancy should be taken into account: poor quality of Google satellite photographs, difficulties in determining the body axis, selection of herds or animals within herds, lack of blinding in the evaluation, possible subconscious bias, and, most importantly, high sensitivity of the calculated main directions of the Rayleigh vectors to some kind of bias or to some overlooked or ignored confounder. This factor could easily have led to an unsubstantiated positive conclusion about the existence of magnetoreception.Comment: Added electronic supplement with source dat

Comparando dos métodos de estimación del tamaño de las redes personales

En este artículo comparamos dos métodos para la estimación del tamaño de las redes personales utilizando una muestra representativa de Estados Unidos a nivel nacional. Ambos métodos se basan en la habilidad de las personas encuestadas para estimar el número de personas que conocen en subpoblaciones específicas de EE.UU. (ej.: diabéticos, nativo-americanos) y gente en categorías específicas de relación (ej.: familia inmediata, compañeros de trabajo). Los resultados muestran una remarcable similitud entre el tamaño medio de la red obtenido por ambos métodos (aproximadamente 291). Se obtuvieron resultados similares con una muestra nacional distinta. La tentativa de corroboración de nuestras estimaciones mediante una reproducción exacta de la encuesta entre un segmento de población propenso a tener redes más amplias (el clero), dio como resultado un tamaño medio de la red superior. Una investigación extensiva sobre la existencia de efectos de respuesta mostró algunas preferencias por usar ciertos números a la hora de realizar estimaciones, pero nada que afectase de forma significativa a la estimación de tamaño de la red más allá del 6 por ciento. Nuestra conclusión es que ambos métodos utilizados para la estimación del tamaño de las redes personales proporcionan resultados válidos y fiables del tamaño de la red real, pero quedan algunas cuestiones pendientes sobre la exactitud.In this paper we compare two methods for estimating the size of personal networks using a nationally representative sample of the United States. Both methods rely on the ability of respondents to estimate the number of people they know in specific subpopulations of the U.S. (e.g., diabetics, Native Americans) and people in particular relation categories (e.g., immediate family, coworkers). The results demonstrate a remarkable similarity between the average network size generated by both methods (approximately 291). Similar results were obtained with a separate national sample. An attempt to corroborate our estimates by replicati among a population we suspect has large networks (clergy), yielded a larger average network size. Extensive investigation into the existence of response effects showed some preference for using certain numbers when making estimates, but nothing that would significantly affect the estimate of network size beyond about 6 percent. We conclude that both methods for estimating personal network size yield valid and reliable proxies for actual network size, but questions about accuracy remain