Extending electron orbital precession to the molecular case: Can orbital alignment be used to observe wavepacket dynamics?

The complexity of ultrafast molecular photoionization presents an obstacle to the modelling of pump-probe experiments. Here, a simple optimized model of atomic rubidium is combined with a molecular dynamics model to predict quantitatively the results of a pump-probe experiment in which long range rubidium dimers are first excited, then ionized after a variable delay. The method is illustrated by the outline of two proposed feasible experiments and the calculation of their outcomes. Both of these proposals use Feshbach 87Rb2 molecules. We show that long-range molecular pump-probe experiments should observe spin-orbit precession given a suitable pump-pulse, and that the associated high-frequency beat signal in the ionization probability decays after a few tens of picoseconds. If the molecule was to be excited to only a single fine structure state state, then a low-frequency oscillation in the internuclear separation would be detectable through the timedependent ionization cross section, giving a mechanism that would enable observation of coherent vibrational motion in this molecule.Comment: 9 pages, 10 figures, PRA submissio

Finite Element Fracture Analysis of Steel-Concrete Bond

The effect of deformation pattern on bond strength is studied using a finite element model of a beam-end specimen. The model includes concrete, steel, and transverse reinforcement substructures. A splitting crack is assumed to occur along the specimen center line, and only onehalf of the specimen is modeled. Splitting concrete is modeled using the nonlinear fracture mechanics approach known as the "fictitious crack model" (Hillerborg et al. 1976). The steelconcrete interface is modeled using special link elements that follow a Mohr-Coulomb failure law. Bond strength is studied as a function of rib height, rib shape, concrete cover, lead length, embedded length, and transverse reinforcement. A 1 in. square bar with ribs heights of 0.06 in. or 0.09 in. is used. Models with 1, 2, and 3 in. covers and one-half in. and 2 in. lead lengths are studied. Embedded lengths range from 0.82 to 7.86 in. The study shows that steel-concrete interaction can be accurately represented by placing interface elements only on the compression faces of the ribs. Under conditions of low cover and no transverse reinforcement, bond force is not dependent on rib height or rib shape; however, an increase in rib height produces an increase in the initial stiffness of the load-slip curves. Under conditions of increased concrete cover, bond force and the initial stiffness of the load-slip curves mcrease. Under conditions of increased bar confinement provided by additional lead length, bond strengths increase compared to bars with lower lead lengths. Bond force increases with an increase in embedded length. However, the amount of concrete that is split at failure is not proportional to the embedded length. The degree of splitting Qateral displacement at the front face of the specimen) up to the peak load is not dependent on rib height or shape but is dependent on concrete cover. Lateral displacements after the peak load increase with an increase in rib height Under conditions of increased confinement provided by transverse reinforcement, bond strength increases compared to models without transverse reinforcement. A statical model of steel in contact with concrete provides a means of relating the clamping force provided by the concrete to the pull-out force of the reinforcing bar

Bond of Epoxy-Coated Reinforcement: Splices

The effects of epoxy coating and transverse reinforcement on the splice strength of reinforcing bars in concrete are described. A total of 65 beam and slab splice specimens containing No. 6 and No. 8 bars were tested. The average coating thickness ranged from 6 to 11 mils (0.15 to 0.28 mm). Three deformation patterns were used. All but one group of specimens contained Class B ACI/Class C AASHTO splices. The results of the current study are analyzed, along with the results of 48 specimens from earlier studies, and used to develop improved development length modification factors for use with epoxy-coated bars. Epoxy coatings are found to reduce splice strength significantly; however, the extent of the reduction is less than that used to select the development length modification factors in the 1989 ACI Building Code and 1989 AASHTO Bridge Specifications. The percentage decrease in splice strength caused by epoxy coating is independent of the degree of confining reinforcement, which provides approximately the same percentage increase in the strength of splices for both coated and uncoated bars. A maximum development length modification factor of 1.35 is applicable for design with epoxy-coated reinforcement. An alternate factor of 1.20 is applicable for epoxy-coated bars with a defined minimum amount of transverse reinforcement if the positive effects of that transverse reinforcement are not already taken into account in the design provisions. Thus, the 1.20 factor is not applicable to the ACI Building Code, but is applicable to the AASHTO Bridge Specifications. This is the second in a series of papers describing research at the University of Kansas on epoxy-coated reinforcement. The research is aimed at gaining a better understanding of the bond of epoxy-coated reinforcement to concrete and developing design procedures that accurately reflect the changes in bond strength caused by epoxy coating

Bond of Epoxy-Coated Reinforcement to Concrete: Splices

The effects of epoxy coating and transverse reinforcement on the splice strength of reinforcing bars in concrete are described. Tests included 65 beam and slab splice specimens for members containing No. 6 and No. 8 bars. The average coating thickness ranged from 6 to 11 mis. Three deformation patterns were used in the study. All but one group of specimens contained Class B ACI/Class C AASHTO splices. The results of the current study are analyzed, along with the results of 48 specimens from earlier studies and used to develop improved development length modification factors for use with epoxy coated bars. Epoxy coatings are found to significantly reduce splice strength. However, the extent of the reduction is less than used to select the development length modification factors in the 1989 AASHTO Bridge Specifications and 1989 ACI Building Code. The percentage decrease in splice strength caused by epoxy coating is independent of the degree of confining reinforcement, which provides approximately the same percentage increase in the strength of splices of both coated and uncoated reinforcement. A development length modification factor of 1.35 is applicable for design with epoxy-coated reinforcement. An alternate factor of 1.20 is applicable for epoxy-coated bars with a minimum amount of transverse reinforcement, if the positive effects of that transverse reinforcement are not already taken into account in the design provisions. The 1.20 factor is, thus, not applicable to the ACI Building Code but is applicable to the AASHTO Bridge Specifications. This report is the third in a continuing series describing research at the University of Kansas to gain a better understanding and develop accurate design procedures that reflect the changes in bond strength caused by the use of epoxy coating on reinforcing bars

The Cost-Effectiveness of Directly Observed Highly-Active Antiretroviral Therapy in the Third Trimester in HIV-Infected Pregnant Women

Background: In HIV-infected pregnant women, viral suppression prevents mother-to-child HIV transmission. Directly observed highly-active antiretroviral therapy (HAART) enhances virological suppression, and could prevent transmission. Our objective was to project the effectiveness and cost-effectiveness of directly observed administration of antiretroviral drugs in pregnancy. Methods and Findings: A mathematical model was created to simulate cohorts of one million asymptomatic HIV-infected pregnant women on HAART, with women randomly assigned self-administered or directly observed antiretroviral therapy (DOT), or no HAART, in a series of Monte Carlo simulations. Our primary outcome was the quality-adjusted life expectancy in years (QALY) of infants born to HIV-infected women, with the rates of Caesarean section and HIV-transmission after DOT use as intermediate outcomes. Both self-administered HAART and DOT were associated with decreased costs and increased life-expectancy relative to no HAART. The use of DOT was associated with a relative risk of HIV transmission of 0.39 relative to conventional HAART; was highly cost-effective in the cohort as a whole (cost-utility ratio $14,233 per QALY); and was cost-saving in women whose viral loads on self-administered HAART would have exceeded 1000 copies/ml. Results were stable in wide-ranging sensitivity analyses, with directly observed therapy cost-saving or highly cost-effective in almost all cases. Conclusions: Based on the best available data, programs that optimize adherence to HAART through direct observation in pregnancy have the potential to diminish mother-to-child HIV transmission in a highly cost-effective manner. Targeted use of DOT in pregnant women with high viral loads, who could otherwise receive self-administered HAART would be a cost-saving intervention. These projections should be tested with randomized clinical trials

A pump-probe study of the formation of rubidium molecules by ultrafast photoassociation of ultracold atoms

An experimental pump-probe study of the photoassociative creation of translationally ultracold rubidium molecules is presented together with numerical simulations of the process. The formation of loosely bound excited-state dimers is observed as a first step towards a fully coherent pump-dump approach to the stabilization of Rb$_2$ into its lowest ground vibrational states. The population that contributes to the pump-probe process is characterized and found to be distinct from a background population of pre-associated molecules.Comment: Accepted for publication in Phys. Rev. A (10 pages, 9 figures

Functional interaction between Sequestosome-1/p62 and Autophagy-Linked FYVE-containing protein WDFY3 in human osteoclasts

Peer reviewedPostprin

Contested discourses in social tourism:A relational political economy perspective

Social tourism initiatives often have economic as well as objectives, particularly national schemes such as the Spanish IMSERSO programme, designed to stimulate off-season tourism in mass coastal tourism destinations. Yet, there is little evidence of how such schemes responded to crises or that explores the effects on the tourism industry actors responsible for programme delivery. This article applies a relational political economy approach to assess the contested discourses surrounding the governance of the scheme. We examine the evolution of the IMSERSO programme longitudinally following the global financial crisis and up until the COVID-19 pandemic to assess the relational dynamics at play social tourism governance on destination stakeholders, outlining implications for social tourism policies internationally

Iridium-catalysed ortho-directed deuterium labelling of aromatic esters – an experimental and theoretical study on directing group chemoselectivity

Herein we report a combined experimental and theoretical study on the deuterium labelling of benzoate ester derivatives, utilizing our developed iridium N-heterocyclic carbene/phosphine catalysts. A range of benzoate esters were screened, including derivatives with electron-donating and -withdrawing groups in the para- position. The substrate scope, in terms of the alkoxy group, was studied and the nature of the catalyst counter-ion was shown to have a profound effect on the efficiency of isotope exchange. Finally, the observed chemoselectivity was rationalized by rate studies and theoretical calculations, and this insight was applied to the selective labelling of benzoate esters bearing a second directing group

Transesophageal Echocardiographically-Confirmed Pulmonary Vein Thrombosis in Association with Posterior Circulation Infarction

Pulmonary venous thromboembolism has only been identified as a cause of stroke with pulmonary arteriovenous malformations/fistulae, pulmonary neoplasia, transplantation or lobectomy, and following percutaneous radiofrequency ablation of pulmonary vein ostia in patients with atrial fibrillation. A 59-year-old man presented with a posterior circulation ischemic stroke. ‘Unheralded’ pulmonary vein thrombosis was identified on transesophageal echocardiography as the likely etiology. He had no further cerebrovascular events after intensifying antithrombotic therapy. Twenty-eight months after initial presentation, he was diagnosed with metastatic pancreatic adenocarcinoma and died 3 months later. This report illustrates the importance of doing transesophageal echocardiography in presumed ‘cardioembolic’ stroke, and that potential ‘pulmonary venous thromboembolic’ stroke may occur in patients without traditional risk factors for venous thromboembolism. Consideration should be given to screening such patients for occult malignancy