21,639 research outputs found
Aggregation Of Chlorophyll a Probed By Resonance Light Scattering Spectroscopy
We report the resonance light scattering (RLS) spectra of chlorophyll a aggregated in a 9:1 solution of formamide and pH 6.8 phosphate buffer. The aggregate formed after 2 h of mixing, referred to as Chl(469), shows a strong scattering feature at 469 nm (Soret band) and a much weaker feature at 699 nm (Q(y) band). A kinetic investigation confirmed that the aggregation process is cooperative, and also detected one intermediate (Chl(458)) with a strong RLS spectrum but only a weak CD spectrum. We propose that aggregation proceeds via at least three steps: 1) formation of a nucleating species, probably a dimer of chlorophylls; 2) formation of large aggregates with little or no secondary structure (e.g., Chl(458)); and 3) conformational change to form helical aggregate (Chl(469))
Interactive Gaming Reduces Experimental Pain With or Without a Head Mounted Display
While virtual reality environments have been shown to reduce pain, the precise mechanism that produces the pain attenuating effect has not been established. It has been suggested that it may be the ability to command attentional resources with the use of head mounted displays (HMDs) or the interactivity of the environment. Two experiments compared participantsâ pain ratings to high and low levels of electrical stimulation while engaging in interactive gaming with an HMD. In the first, gaming with the HMD was compared to a positive emotion induction condition; and in the second experiment the HMD was compared to a condition in which the game was projected onto a wall. Interactive gaming significantly reduced numerical ratings of painful stimuli when compared to the baseline and affect condition. However, when the two gaming conditions were directly compared, they equally reduced participantsâ pain ratings. These data are consistent with past research showing that interactive gaming can attenuate experimentally induced pain and its effects are comparable whether presented in a head mounted display or projected on a wall
Final state interaction in with I=1/2 and 3/2 channels
The final state interaction contribution to decays is computed for the
channel within a light-front relativistic three-body model for
the final state interaction. The rescattering process between the kaon and two
pions in the decay channel is considered. The off-shell decay amplitude is a
solution of a four-dimensional Bethe-Salpeter equation, which is decomposed in
a Faddeev form. The projection onto the light-front of the coupled set of
integral equations is performed via a quasi-potential approach. The S-wave
interaction is introduced in the resonant isospin and the
non-resonant isospin channels. The numerical solution of the light-front
tridimensional inhomogeneous integral equations for the Faddeev components of
the decay amplitude is performed perturbatively. The loop-expansion converges
fast, and the three-loop contribution can be neglected in respect to the
two-loop results for the practical application. The dependence on the model
parameters in respect to the input amplitude at the partonic level is exploited
and the phase found in the experimental analysis, is fitted with an appropriate
choice of the real weights of the isospin components of the partonic amplitude.
The data suggests a small mixture of total isospin to the dominant
one. The modulus of the unsymmetrized decay amplitude, which presents a deep
valley and a following increase for masses above GeV, is fairly
reproduced. This suggests the assignment of the quantum numbers to the
isospin 1/2 resonance
Cape Verde: The Case for Euroization
After 10 years of a fixed exchange rate against the euro and a deepening integration with the European Union (EU), the authorities of Cape Verde maintain a strong commitment to nominal stability and are now considering the official euroization of the country. Compared to the current pegging, euroization could be costly if the economic conditions of Cape Verde were to require control over the interest rates and the exchange rate. Given the strong economic and financial integration between Cape Verde and Europe, and the fact that Cape Verde records inflation rates at levels that are similar to those of the European Monetary Union (EMU), the relevant issue is whether the European Central Bank (ECB) monetary policy fits the needs of Cape Verde. In order to answer this question, we empirically assess the synchronization between the business cycle of Cape Verde and the business cycle of the EMU. For that purpose, we compute output gaps and then use conventional correlation measures as well as other indicators recently suggested in the literature. Replicating the methodology for each of the current 27 EU members, our results show that Cape Verde ranks better than several EU countries and even better than some EMU countries. We thus argue that there is a strong case for the euroization of Cape Verde. Euroization would secure the benefits already attained with the pegging to the euro and would warrant additional benefits, most likely with no relevant costs stemming from inappropriate ECB monetary policies.Africa, Cape Verde, European Monetary Union, Euroization, Business Cycles
Intermolecular interactions in N-(ferrocenylmethyl)anthracene-9-carboxamide
The title compound, [Fe(Câ
Hâ
)(CââHââNO)], was synthesized from the coupling reaction of anthracene-9-carboxylic acid and ferrocenylmethylamine. The ferrocenyl (Fc) group and the anthracene ring system both lie approximately orthogonal to the amide moiety. An amide-amide interaction (along the a axis) is the principal interaction [N...O = 2.910 (2) Ă
]. A C-H...Ï(arene) interaction [C...centroid = 3.573 (2) Ă
] and a C-H...O interaction [C...O = 3.275 (3) Ă
] complete the hydrogen bonding; two short (Fc)C...C(anthracene) contacts are also present
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