Symmetry of Hydrogen Bonds in Two Enols in Solution.

The enols of 4-cyano-2,2,6,6-tetramethyl-3,5-heptanedione and of nitromalonamide were prepared as statistical mixtures of 18O n ( n = 0, 1, 2) isotopologues. The symmetries of their hydrogen bonds were probed by isotopic perturbation of their 13CO NMR signals. The former mixture shows a total of four signals, due to both intrinsic and perturbation isotope shifts. Therefore, that enol is a mixture of tautomers with an asymmetric hydrogen bond. In contrast, the mixture of isotopologues of nitromalonamide enol shows only two signals, due to an intrinsic isotope shift. Therefore, this is the first case, to be compared with the FHF- anion, of a neutral species with a single symmetric structure in solution and with a centered hydrogen

Lithuanians in the Shadow of Three Eagles: Vincas Kudirka, Martynas Jankus, Jonas Šliūpas and the Making of Modern Lithuania

The Lithuanian national movement in the late nineteenth and early twentieth centuries was an international phenomenon involving Lithuanian communities in three countries: Russia, Germany and the United States. To capture the international dimension of the Lithuanian national movement this study offers biographies of three activists in the movement, each of whom spent a significant amount of time living in one of the three “parts” of the Lithuanian nation: Vincas Kudirka, Martynas Jankus and Jonas Šliūpas. The biographies focus on the following questions. To what extent did each of the three activists assimilate into a “foreign” (i.e., non-Lithuanian) culture and was this a voluntary process? How did they free themselves from foreign cultural dominance? How did they understand nationality in general and Lithuanian nationality in particular? What goals did they incorporate into their nationalist agendas? What causes of anti-Semitism and philosemitism can be identified by analyzing their discourse about Jews? The conclusion puts the answers to some of these questions into comparative perspective. This study uses published and archival sources in seven languages from libraries and archives in seven countries—some of which have never been used before. It is the first to use the unpublished typescript of Jonas Šliūpas’ 1942 autobiography, which, until recently, was unavailable to researchers

Study of microcomputer applications in police services

Issued as Final report, Project no. A-364

Hydrological model parameter instability: A source of additional uncertainty in estimating the hydrological impacts of climate change?

International audienceThis paper investigates the uncertainty of hydrological predictions due to rainfall-runoff model parameters in the context of climate change impact studies. Two sources of uncertainty were considered: (i) the dependence of the optimal parameter set on the climate characteristics of the calibration period and (ii) the use of several posterior parameter sets over a given calibration period. The first source of uncertainty often refers to the lack of model robustness, while the second one refers to parameter uncertainty estimation based on Bayesian inference. Two rainfall-runoff models were tested on 89 catchments in northern and central France. The two sources of uncertainty were assessed in the past observed period and in future climate conditions. The results show that, given the evaluation approach followed here, the lack of robustness was the major source of variability in streamflow projections in future climate conditions for the two models tested. The hydrological projections generated by an ensemble of posterior parameter sets are close to those associated with the optimal set. Therefore, it seems that greater effort should be invested in improving the robustness of models for climate change impact studies, especially by developing more suitable model structures and proposing calibration procedures that increase their robustness

Atomistic calculations of Ga(NAsP)/GaP(N) quantum wells on silicon substrate: Band structure and optical gain

International audienceBand structure calculations of strained Ga(NAsP) quantum wells are performed within the framework of the extended-basis sp3d5s* tight-binding model. The nitrogen contribution is taken into account by introducing an additional sN orbital into the tight-binding basis. Biaxial strain effects on the band alignment of bulk Ga(NAsP) is studied for the ultra-diluted regime. We demonstrate a good agreement with experimental data both for transition energies and optical gain in Ga(NAsP) quantum wells. The effect of N incorporation in the laser active areas is simulated

Comment on “The role of electrostatic induction in secondary isotope effects on acidity” by E. A. Halevi, New J. Chem., 2014, 38

We reaffirm our conclusion that secondary deuterium isotope effects on acidity are due to n-σ∗ delocalization that decreases vibrational frequencies and zero-point energies. We reject an electrostatic or inductive explanation that arises from the anharmonicity of the C-H bond. We address calculated values of atomic charges, dipole moments, and dipole-moment derivatives dμ/dr, and we show the isotope effect to be a stereoelectronic phenomenon arising from harmonic vibrations

Virtual reality gaming elevates heart rate but not energy expenditure compared to conventional exercise in adult males

Virtual reality using head-mounted displays (HMD) could provide enhanced physical load during active gaming (AG) compared to traditional displays. We aimed to compare the physical load elicited by conventional exercise and AG with an HMD. We measured energy expenditure (EE) and heart rate (HR) in nine healthy men (age: 27 ± 5 years) performing three testing components in a randomised order: walking at 6 km/h (W6), AG, and AG with an additional constraint (AGW; wrist-worn weights). Although we found that HR was not significantly different between W6 and the two modes of AG, actual energy expenditure was consistently lower in AG and AGW compared to W6. We observed that playing AG with wrist-worn weights could be used as a means of increasing energy expenditure only at maximum game level, but ineffective otherwise. Our findings indicate that AG in an HMD may not provide a sufficient stimulus to meet recommended physical activity levels despite increased psychophysiological load. The differential outcomes of measures of HR and EE indicates that HR should not be used as an indicator of EE in AG. Yet, adding a simple constraint (wrist-worn weights) proved to be a simple and effective measure to increase EE during AG