Charge transfer to solvent dynamics in iodide aqueous solution studied at ionization threshold

We explore the early-time electronic relaxation in NaI aqueous solution exposed to a short UV laser pulse. Rather than initiating the charge transfer reaction by resonant photoexcitation of iodide, in the present time-resolved photoelectron spectroscopy study the charge-transfer-to-solvent (CTTS) states are populated via electronic excitation above the vacuum level. By analyzing the temporal evolution of electron yields from ionization of two transient species, assigned to CTTS and its first excited state, we determine both their ultrafast population and relaxation dynamics. Comparison with resonant- excitation studies shows that the highly excited initial states exhibit similar relaxation characteristics as found for resonant excitation. Implications for structure and dynamical response of the hydration cage are discussed

PISA: a political project and a research agenda

PISA (Programme for International Student Assessment) is one of two large scale international comparative projects of student assessment that now exert considerable influence upon school science education policy, the other being TIMSS (Trends in International Mathematics and Science Study). This paper focuses on PISA, now the most influential study. This article outlines the origins of PISA, identifies some of the challenges in its construction and the claims made for it. It argues that while the statistical and methodological aspects of PISA have received much research attention, other elements of PISA have been largely ignored. In particular, there are several outcomes of PISA testing that point towards a significant research agenda. In addition, the political, ideological and economic assumptions underpinning the PISA project have implications for school science curriculum policy that deserve closer scrutiny and debate

Time-of-flight electron spectrometer for a broad range of kinetic energies

A newly constructed time-of-flight electron spectrometer of the magnetic bottle type is characterized for electron detection in a broad range of kinetic energies. The instrument is designed to measure the energy spectra of electrons generated from liquids excited by strong laser fields and photons in the range of extreme ultra violet and soft X-rays. Argon inner shell electrons were recorded to calibrate the spectrometer and investigate its characteristics, such as energy resolution and collection efficiency. Its energy resolution ΔE/E of 1.6% allows resolving the Ar 2p spin orbit structure at kinetic energies higher than 100 eV. The collection efficiency is determined and compared to that of the spectrometer in its field-free configuration

Delta degrees of freedom in antisymmetrized molecular dynamics and (p,p') reactions in the delta region

Delta degrees of freedom are introduced into antisymmetrized molecular dynamics (AMD). This is done by increasing the number of basic states in the AMD wave function, introducing a Skyrme-type delta-nucleon potential, and including $NN\leftrightarrow N\Delta$ reactions in the collision description. As a test of the delta dynamics, the extended AMD is applied to (p,p$'$) recations at $E_{\rm lab}=800$ MeV for a $^{12}$C target. It is found that the ratio and the absolute values for delta peak and quasielastic peak (QEP) in the $^{12}$C(p,p$'$) reaction are reproduced for angles \Theta_{\rm lab} \agt 40^\circ, pointing to a correct treatment of the delta dynamics in the extended AMD. For forward angles the QEP is overestimated. The results of the AMD calculations are compared to one-step Monte Carlo (OSMC) calculations and a detailed analysis of multi-step and delta potential effects is given. As important side results we present a way to apply a Gallilei invariant theory for (N,N$'$) reactions up to $E_{\rm lab} \approx 800$ MeV which ensures approximate Lorentz invariance and we discuss how to fix the width parameter $\nu$ of the single particle momentum distribution for outgoing nucleons in the AMD calculation.Comment: 28 pages, revtex, 12 figures included, figures are also available upon request as postscript files from the authors (e-mail: [email protected]), submitted to Phys. Rev.

On large deviation properties of Erdos-Renyi random graphs

We show that large deviation properties of Erd\"os-R\'enyi random graphs can be derived from the free energy of the $q$-state Potts model of statistical mechanics. More precisely the Legendre transform of the Potts free energy with respect to $\ln q$ is related to the component generating function of the graph ensemble. This generalizes the well-known mapping between typical properties of random graphs and the $q\to 1$ limit of the Potts free energy. For exponentially rare graphs we explicitly calculate the number of components, the size of the giant component, the degree distributions inside and outside the giant component, and the distribution of small component sizes. We also perform numerical simulations which are in very good agreement with our analytical work. Finally we demonstrate how the same results can be derived by studying the evolution of random graphs under the insertion of new vertices and edges, without recourse to the thermodynamics of the Potts model.Comment: 38 pages, 9 figures, Latex2e, corrected and extended version including numerical simulation result

Suppression of quantum oscillations and the dependence on site energies in electronic excitation transfer in the Fenna-Matthews-Olson trimer

Energy transfer in the photosynthetic complex of the Green Sulfur Bacteria known as the Fenna-Matthews-Olson (FMO) complex is studied theoretically taking all three subunits (monomers) of the FMO trimer and the recently found eighth bacteriochlorophyll (BChl) molecule into account. We find that in all considered cases there is very little transfer between the monomers. Since it is believed that the eighth BChl is located near the main light harvesting antenna we look at the differences in transfer between the situation when BChl 8 is initially excited and the usually considered case when BChl 1 or 6 is initially excited. We find strong differences in the transfer dynamics, both qualitatively and quantitatively. When the excited state dynamics is initialized at site eight of the FMO complex, we see a slow exponential-like decay of the excitation. This is in contrast to the oscillations and a relatively fast transfer that occurs when only seven sites or initialization at sites 1 and 6 is considered. Additionally we show that differences in the values of the electronic transition energies found in the literature lead to a large difference in the transfer dynamics

Neutrino cross sections at high energies and the future observations of ultrahigh-energy cosmic rays

We show that future detectors of ultrahigh-energy cosmic-ray neutrinos will be able to measure neutrino-nucleon cross section at energies as high as 10^{11}GeV or higher. We find that the flux of up-going charged leptons per unit surface area produced by neutrino interactions below the surface is inversely proportional to the cross section. This contrasts with the rate of horizontal air showers (HAS) due to neutrino interactions in the atmosphere, which is proportional to the cross section. Thus, by comparing the HAS and up-going air shower (UAS) rates, the neutrino-nucleon cross section can be inferred. Taken together, up-going and horizontal rates ensure a healthy total event rate, regardless of the value of the cross section.Comment: 4 pages, 2 figures, revtex; final draf

Prediction of photoperiodic regulators from quantitative gene circuit models

Photoperiod sensors allow physiological adaptation to the changing seasons. The external coincidence hypothesis postulates that a light-responsive regulator is modulated by a circadian rhythm. Sufficient data are available to test this quantitatively in plants, though not yet in animals. In Arabidopsis, the clock-regulated genes CONSTANS (CO) and FLAVIN, KELCH, F-BOX (FKF1) and their lightsensitive proteins are thought to form an external coincidence sensor. We use 40 timeseries of molecular data to model the integration of light and timing information by CO, its target gene FLOWERING LOCUS T (FT), and the circadian clock. Among other predictions, the models show that FKF1 activates FT. We demonstrate experimentally that this effect is independent of the known activation of CO by FKF1, thus we locate a major, novel controller of photoperiodism. External coincidence is part of a complex photoperiod sensor: modelling makes this complexity explicit and may thus contribute to crop improvement

Humiliated fury is not universal: the co-occurrence of anger and shame in the United States and Japan

It has been widely believed that individuals transform high-intensity shame into anger because shame is unbearably painful. This phenomenon was first coined “humiliated fury,” and it has since received empirical support. The current research tests the novel hypothesis that shame-related anger is not universal, yet hinges on the cultural meanings of anger and shame. Two studies compared the occurrence of shamerelated anger in North American cultural contexts (where shame is devalued and anger is valued) to its occurrence in Japanese contexts (where shame is valued and anger is devalued). In a daily-diary study, participants rated anger and shame feelings during shame situations that occurred over one week. In a vignette study, participants rated anger and shame in response to standardised shame vignettes that were generated in previous research by either U.S. or Japanese respondents. Across the two studies, and in line with previous research on humiliated fury, shame predicted anger for U.S. participants. Yet, neither in the daily diary study nor for the Japanese-origin vignettes, did we find shame-related anger in Japanese participants. Only when presented with U.S.-origin vignettes, did Japanese respondents in the vignette study report shame-related anger. The findings suggest that shame-related anger is a culture-specific phenomenon

Long-Term Effects of Inhaled Budesonide for Bronchopulmonary Dysplasia

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