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MUTUAL EXCHANGES SUPPORT ACADEMIC AND COMMUNITY COLLABORATION Many collaborative efforts between academic and public health institutions are based on formally structured agreements that serve the traditional mission of academia and […]

Abstract Background We quantified the air quality benefits of a smoke-free workplace law in Boston Massachusetts, U.S.A., by measuring air pollution from secondhand smoke (SHS) in 7 pubs before and after the law, comparing actual ventilation practices to engineering society (ASHRAE) recommendations, and assessing SHS levels using health and comfort indices. Methods We performed real-time measurements of respirable particle (RSP) air pollution and particulate polycyclic aromatic hydrocarbons (PPAH), in 7 pubs and outdoors in a model-based design yielding air exchange rates for RSP removal. We also assessed ventilation rates from carbon dioxide concentrations. We compared RSP air pollution to the federal Air Quality Index (AQI) and the National Ambient Air Quality Standard (NAAQS) to assess health risks, and assessed odor and irritation levels using published SHS-RSP thresholds. Results Pre-smoking-ban RSP levels in 6 pubs (one pub with a non-SHS air quality problem was excluded) averaged 179 μg/m3, 23 times higher than post-ban levels, which averaged 7.7 μg/m3, exceeding the NAAQS for fine particle pollution (PM2.5) by nearly 4-fold. Pre-smoking ban levels of fine particle air pollution in all 7 of the pubs were in the Unhealthy to Hazardous range of the AQI. In the same 6 pubs, pre-ban indoor carcinogenic PPAH averaged 61.7 ng/m3, nearly 10 times higher than post-ban levels of 6.32 ng/m3. Post-ban particulate air pollution levels were in the Good AQI range, except for 1 venue with a defective gas-fired deep-fat fryer, while post-ban carcinogen levels in all 7 pubs were lower than outdoors. Conclusion During smoking, although pub ventilation rates per occupant were within ASHRAE design parameters for the control of carbon dioxide levels for the number of occupants present, they failed to control SHS carcinogens or RSP. Nonsmokers' SHS odor and irritation sensory thresholds were massively exceeded. Post-ban air pollution measurements showed 90% to 95% reductions in PPAH and RSP respectively, differing little from outdoor concentrations. Ventilation failed to control SHS, leading to increased risk of the diseases of air pollution for nonsmoking workers and patrons. Boston's smoking ban eliminated this risk.

We show that the finitely generated simple left orderable groups $G_{\!\unicode[STIX]{x1D70C}}$ constructed by the first two authors in Hyde and Lodha [Finitely generated infinite simple groups of homeomorphisms of the real line. Invent. Math. (2019), doi:10.1007/s00222-019-00880-7] are uniformly perfect—each element in the group can be expressed as a product of three commutators of elements in the group. This implies that the group does not admit any homogeneous quasimorphism. Moreover, any non-trivial action of the group on the circle, which lifts to an action on the real line, admits a global fixed point. It follows that any faithful action on the real line without a global fixed point is globally contracting. This answers Question 4 of the third author [A. Navas. Group actions on 1-manifolds: a list of very concrete open questions. Proceedings of the International Congress of Mathematicians, Vol. 2. Eds. B. Sirakov, P. Ney de Souza and M. Viana. World Scientific, Singapore, 2018, pp, 2029–2056], which asks whether such a group exists. This question has also been answered simultaneously and independently, using completely different methods, by Matte Bon and Triestino [Groups of piecewise linear homeomorphisms of flows. Preprint, 2018, arXiv:1811.12256]. To prove our results, we provide a characterization of elements of the group $G_{\!\unicode[STIX]{x1D70C}}$ which is a useful new tool in the study of these examples. [ABSTRACT FROM AUTHOR]

Analyzes the special vocabulary of teenagers, with an examination of the various themes running through teen "rat" talk. Suggests that the roots of adolescent alienation are not so deep as the existence of this vocabulary and other elements of their behavior suggest. (RL)

A comparative analysis of the effects of alpha-helical peptides, LA(sub)12 and LA(sub)24, on 1-palmitoyl-2-oleoylphosphatidylcholine membranes is presented. Results indicate that the effects of the peptides on the membrane dynamics and organization differ and that LA(sub)12 causes a greater oxygen transport than LA(sub)24 within the lipid bilayer. Data suggest the differences are due to the hydrophobic surfaces properties of the peptides.

The interaction of a spin 1/2 system with two continuous wave transverse electromagnetic fields is studied using the dressed-atom formalism and the Floquet theory. The equation of motion of the density matrix in the presence of two fields is solved and used to analyze the response of the spin system to double irradiation under steady state. In the average frequency rotating frame, the diagonal elements of the density matrix oscillate at even harmonics of the frequency difference, while the off-diagonal elements oscillate at odd harmonics. The spectral response of the spin system can be predicted by applying the conservation rules: The frequency spectrum is a consequence of the conservation of total angular momentum, while the resonance condition is the result of the conservation of energy. The interpretive and predictive nature of the theoretical framework presented is illustrated by the treatment of the classical Anderson experiment and the simulation of the splitting of the multiquantum signal at high frequency difference. Approximate expressions for the population differences and coherences are derived and graphic representation is used to study the general nonlinear dependence on spectral parameters. At low values of the saturation parameter S, the n-quantum absorption is proportional to dT2S(n-1)/2, where d=1/2γH. Therefore, the signal amplitude is proportional not only to T2, but also to powers of T1T2, which makes the multiquantum signals more sensitive to relaxation rates than conventional one-photon displays. The frequency difference swept line shape of the multiquantum signal depends on both T1 and T2. However, when T2≪T1, the new spectroscopic dimension, namely, the frequency difference, can be used to determine the spin–lattice relaxation time. Several spectroscopic features of multiquantum signals are discussed in the context of the general mathematical equivalence of double irradiation and amplitude modulation spectroscopy. [ABSTRACT FROM AUTHOR]

Irradiation of a single homogeneous electron paramagnetic resonance (EPR) transition by two microwave sources separated by Δf, where Δf≪ the linewidth, results in the production of intermodulation sidebands at f0±(k+1/2)Δf, where f0 is the mean of the two irradiating frequencies and k is an integer ≥1. These sidebands can be seen directly with a microwave spectrum analyzer. Any one of the sidebands can be observed by suitable phase sensitive detection and displayed as a function of the polarizing magnetic field H0, resulting in a multiquantum EPR spectrum. The widths of the EPR lines decrease as k increases, resulting in improved resolution. The two k=1 transitions can be superimposed, resulting in a signal of double intensity. At saturating microwave power, this double-intensity line is two times less intense than an ordinary EPR line. No magnetic field modulation needs to be used when detecting multiquantum transitions, and pure absorption or pure dispersion signals are obtained with good baseline stability. Considerable attention is paid to the technical problem of irradiating the sample with just two microwave frequencies. In the apparatus described, spurious instrumental sidebands are reduced by 60 dB or more. [ABSTRACT FROM AUTHOR]

The equation of Anderson [Phys. Rev. 102, 151 (1956)] (ω2-ω1)2=(γH0-ω1)2+γ2H21, which describes resonance conditions if relaxation times are long and irradiation at two frequencies is applied to a spin system, has been studied experimentally in the context of continuous wave electron paramagnetic resonance (EPR) spectroscopy. Here ω2 and ω1 are the frequencies of two incident microwave levels, one of which is much stronger than the other and is of amplitude H1. γH0 is the resonant condition if just one frequency is applied. Magnetization at either ω1 or ω2 has been observed as a function of sweep of the static magnetic field, sweep of ω2 and also sweep of the amplitude H1. Observation of magnetization at frequency ω1 corresponding to the strong microwave field H1 replicates the rotary saturation experiment of Redfield [Phys. Rev. 98, 1787 (1955)]. Multi-quantum effects are studied with the two frequencies well separated and also when they lie within the width of a single homogeneous line. In addition, data are shown when both microwave amplitudes are similar and the Anderson equation is no longer correct. The thrust of the work is not only to study the spin physics, but also to develop a basis for our development of rotary resonance as an alternative to field modulation in EPR spectroscopy [J. Chem. Soc. Faraday Trans. 1 85, 3901 (1989)]. [ABSTRACT FROM AUTHOR]

Biomolecular collision rates of 14N-containing nitroxide radical labeled stearic acid with similar 15N-containing species in dimyristoylphosphatidylcholine (DMPC) liposomes have been determined using the saturation-recovery electron spin resonance (ESR) method. It is shown that high microwave observing powers can be used to obtain these rates, thereby increasing the signal-to-noise ratio by about ten times relative to methods previously used. The data are analyzed using the rate-equation approach with inclusion of the observing transition probability. A number of solutions to these equations for other experimental situations and for pulse and continuous wave electron–electron double resonance (ELDOR) are also presented. The bimolecular collision rate of labels at the C16 position was found to be 20% greater than for labels at the C12 position, suggesting that the interaction distance differs at these two positions. Even though the high observing power does not affect the ability to extract bimolecular collision rates, the effective spin-lattice relaxation rates are altered. Plots of these latter rates versus power are linear and the slope can be used to determine the absolute microwave field at the sample for a given input power. [ABSTRACT FROM AUTHOR]