571 research outputs found
Spectroscopy and Dynamics of the Predissociated, Quasi-linear S2 State of Chlorocarbene
In this work, we report on the spectroscopy and dynamics of the quasi-linear S2 state of chlorocarbene, CHCl, and its deuterated isotopologue using optical-optical double resonance (OODR) spectroscopy through selected rovibronic levels of the S1 state. This study, which represents the first observation of the S2 state in CHCl, builds upon our recent examination of the corresponding state in CHF, where pronounced mode specificity was observed in the dynamics, with predissociation rates larger for levels containing bending excitation. In the present work, a total of 14 S2 state vibrational levels with angular momentum ℓ = 1 were observed for CHCl, and 34 levels for CDCl. The range of ℓ in this case was restricted by the pronounced Renner-Teller effect in the low-lying S1 levels, which severely reduces the fluorescence lifetime for levels with Ka \u3e 0. Nonetheless, by exploiting different intermediate S1 levels, we observed progressions involving all three fundamental vibrations. For levels with long predissociation lifetimes, rotational constants were determined by measuring spectra through different intermediate J levels of the S1 state. Plots of the predissociation linewidth (lifetime) vs. energy for various S2 levels show an abrupt onset, which lies near the calculated threshold for elimination to form C(3P) + HCl on the triplet surface. Our experimental results are compared with a series of high level ab initio calculations, which included the use of a dynamically weighted full-valence CASSCF procedure, focusing maximum weight on the state of interest (the singlet and triplet states were computed separately). This was used as the reference for subsequent Davidson-corrected MRCI(+Q) calculations. These calculations reveal the presence of multiple conical intersections in the singlet manifold
Cosmological Tensions and the Transitional Planck Mass Model
In this followup analysis, we update previous constraints on the Transitional
Planck Mass (TPM) modified gravity model using the latest version of EFTCAMB
and provide new constraints using SPT and Planck anisotropy data along with
Planck CMB lensing, BAO, SNe Ia, and an prior from local measurements. We
find that large shifts in the Planck mass lead to large suppression of power on
small scales that is disfavored by both SPT and Planck. Using only SPT TE-EE
data, this suppression of power can be compensated for by an upward shift of
the scalar index to resulting in kmsMpc and a shift in the Planck
mass. Including Planck TT and Planck TE-EE data restricts the
shift to be at with
kmsMpc. Excluding the prior, SPT and Planck data constrain
the shift in the Planck mass to be at with a best-fit value of
, consistent with the CDM limit. In this case kmsMpc, which is partially elevated by the
dynamics of the scalar-field in the late universe. This differs from EDE models
that prefer higher values of when high Planck TT data are
excluded. We additionally constrain TPM using RSD data from BOSS DR 12 and
cosmic shear, galaxy-galaxy lensing, and galaxy clustering data from DES Y1
finding both disfavor transitions close to recombination, but earlier Planck
mass transitions are allowed.Comment: 25 pages, 8 figures, 8 table
Hydrogen-atom Attack on Phenol and Toluene is \u3cem\u3eortho\u3c/em\u3e-directed
The reaction of H + phenol and H/D + toluene has been studied in a supersonic expansion after electric discharge. The (1 + 1′) resonance-enhanced multiphoton ionization (REMPI) spectra of the reaction products, at m/z = parent + 1, or parent + 2 amu, were measured by scanning the first (resonance) laser. The resulting spectra are highly structured. Ionization energies were measured by scanning the second (ionization) laser, while the first laser was tuned to a specific transition. Theoretical calculations, benchmarked to the well-studied H + benzene → cyclohexadienyl radical reaction, were performed. The spectrum arising from the reaction of H + phenol is attributed solely to the ortho-hydroxy-cyclohexadienyl radical, which was found in two conformers (syn and anti). Similarly, the reaction of H/D + toluene formed solely the ortho isomer. The preference for the ortho isomer at 100–200 K in the molecular beam is attributed to kinetic, not thermodynamic effects, caused by an entrance channel barrier that is ∼5 kJ mol−1 lower for ortho than for other isomers. Based on these results, we predict that the reaction of H + phenol and H + toluene should still favour the ortho isomer under elevated temperature conditions in the early stages of combustion (200–400 °C)
Common and Unique Representations in pFC for Place Attractiveness
Although previous neuroimaging research has identified overlapping correlates of subjective value across different reward types in the ventromedial pFC (vmPFC), it is not clear whether this “common currency” evaluative signal extends to the aesthetic domain. To examine this issue, we scanned human participants with fMRI while they made attractiveness judgments of faces and places—two stimulus categories that are associated with different underlying rewards, have very different visual properties, and are rarely compared with each other. We found overlapping signals for face and place attractiveness in the vmPFC, consistent with the idea that this region codes a signal for value that applies across disparate reward types and across both economic and aesthetic judgments. However, we also identified a subregion of vmPFC within which activity patterns for face and place attractiveness were distinguishable, suggesting that some category-specific attractiveness information is retained in this region. Finally, we observed two separate functional regions in lateral OFC: one region that exhibited a category-unique response to face attractiveness and another region that responded strongly to faces but was insensitive to their value. Our results suggest that vmPFC supports a common mechanism for reward evaluation while also retaining a degree of category-specific information, whereas lateral OFC may be involved in basic reward processing that is specific to only some stimulus categories
History and development of trauma registry: lessons from developed to developing countries
BACKGROUND: A trauma registry is an integral component of modern comprehensive trauma care systems. Trauma registries have not been established in most developing countries, and where they exist are often rudimentary and incomplete. This review describes the role of trauma registries in the care of the injured, and discusses how lessons from developed countries can be applied toward their design and implementation in developing countries. METHODS: A detailed review of English-language articles on trauma registry was performed using MEDLINE and CINAHL. In addition, relevant articles from non-indexed journals were identified with Google Scholar. RESULTS: The history and development of trauma registries and their role in modern trauma care are discussed. Drawing from past and current experience, guidelines for the design and implementation of trauma registries are given, with emphasis on technical and logistic factors peculiar to developing countries. CONCLUSION: Improvement in trauma care depends on the establishment of functioning trauma care systems, of which a trauma registry is a crucial component. Hospitals and governments in developing countries should be encouraged to establish trauma registries using proven cost-effective strategies
Ventromedial Frontal Lobe Damage Disrupts Value Maximization in Humans
Recent work in neuroeconomics has shown that regions in orbitofrontal and medial prefrontal cortex encode the subjective value of different options during choice. However, these electrophysiological and neuroimaging studies cannot demonstrate whether such signals are necessary for value-maximizing choices. Here we used a paradigm developed in experimental economics to empirically measure and quantify violations of utility theory in humans with damage to the ventromedial frontal lobe (VMF). We show that people with such damage are more likely to make choices that violate the generalized axiom of revealed preference, which is the one necessary and sufficient condition for choices to be consistent with value maximization. These results demonstrate that the VMF plays a critical role in value-maximizing choice
Lysyl oxidases regulate fibrillar collagen remodelling in idiopathic pulmonary fibrosis.
Idiopathic pulmonary fibrosis (IPF) is a progressive scarring disease of the lung with few effective therapeutic options. Structural remodelling of the extracellular matrix [i.e. collagen cross-linking mediated by the lysyl oxidase (LO) family of enzymes (LOX, LOXL1-4)] might contribute to disease pathogenesis and represent a therapeutic target. This study aimed to further our understanding of the mechanisms by which LO inhibitors might improve lung fibrosis. Lung tissues from IPF and non-IPF subjects were examined for collagen structure (second harmonic generation imaging) and LO gene (microarray analysis) and protein (immunohistochemistry and western blotting) levels. Functional effects (collagen structure and tissue stiffness using atomic force microscopy) of LO inhibitors on collagen remodelling were examined in two models, collagen hydrogels and decellularized human lung matrices. LOXL1/LOXL2 gene expression and protein levels were increased in IPF versus non-IPF. Increased collagen fibril thickness in IPF versus non-IPF lung tissues correlated with increased LOXL1/LOXL2, and decreased LOX, protein expression. β-Aminoproprionitrile (β-APN; pan-LO inhibitor) but not Compound A (LOXL2-specific inhibitor) interfered with transforming growth factor-β-induced collagen remodelling in both models. The β-APN treatment group was tested further, and β-APN was found to interfere with stiffening in the decellularized matrix model. LOXL1 activity might drive collagen remodelling in IPF lungs. The interrelationship between collagen structural remodelling and LOs is disrupted in IPF lungs. Inhibition of LO activity alleviates fibrosis by limiting fibrillar collagen cross-linking, thereby potentially impeding the formation of a pathological microenvironment in IPF
Self-control in decision-making involves modulation of the vmPFC valuation system
Every day, individuals make dozens of choices between an alternative with higher overall value and a more tempting but ultimately inferior option. Optimal decision-making requires self-control. We propose two hypotheses about the neurobiology of self-control: (i) Goal-directed decisions have their basis in a common value signal encoded in ventromedial prefrontal cortex (vmPFC), and (ii) exercising self-control involves the modulation of this value signal by dorsolateral prefrontal cortex (DLPFC). We used functional magnetic resonance imaging to monitor brain activity while dieters engaged in real decisions about food consumption. Activity in vmPFC was correlated with goal values regardless of the amount of self-control. It incorporated both taste and health in self-controllers but only taste in non–self-controllers. Activity in DLPFC increased when subjects exercised self-control and correlated with activity in vmPFC
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