When molecules are coupled to an optical cavity, new light–matter hybrid states, so-called polaritons, are formed due to quantum light–matter interactions. With the experimental demonstrations of ...modifying chemical reactivities by forming polaritons under strong light–matter interactions, theorists have been encouraged to develop new methods to simulate these systems and discover new strategies to tune and control reactions. This review summarizes some of these exciting theoretical advances in polariton chemistry, in methods ranging from the fundamental framework to computational techniques and applications spanning from photochemistry to vibrational strong coupling. Even though the theory of quantum light–matter interactions goes back to the midtwentieth century, the gaps in the knowledge of molecular quantum electrodynamics (QED) have only recently been filled. We review recent advances made in resolving gauge ambiguities, the correct form of different QED Hamiltonians under different gauges, and their connections to various quantum optics models. Then, we review recently developed ab initio QED approaches which can accurately describe polariton states in a realistic molecule–cavity hybrid system. We then discuss applications using these method advancements. We review advancements in polariton photochemistry where the cavity is made resonant to electronic transitions to control molecular nonadiabatic excited state dynamics and enable new photochemical reactivities. When the cavity resonance is tuned to the molecular vibrations instead, ground-state chemical reaction modifications have been demonstrated experimentally, though its mechanistic principle remains unclear. We present some recent theoretical progress in resolving this mystery. Finally, we review the recent advances in understanding the collective coupling regime between light and matter, where many molecules can collectively couple to a single cavity mode or many cavity modes. We also lay out the current challenges in theory to explain the observed experimental results. We hope that this review will serve as a useful document for anyone who wants to become familiar with the context of polariton chemistry and molecular cavity QED and thus significantly benefit the entire community.
Single-walled carbon nanotubes (SWCNTs) with organic sp2 or sp3 hybridization defects allow the robust tunability of many optoelectronic properties in these topologically interesting ...quasi-one-dimensional materials. Recent resonant Raman experiments have illuminated new features in the intermediate-frequency region upon functionalization that change with the degree of functionalization as well as with interactions between defect sites. In this Letter, we report ab initio simulated near-resonant Raman spectroscopy results for pristine and chemically functionalized SWCNT models and find new features concomitant with experimental observations. We are able to assign the character of these features by varying the frequency of the external Raman laser frequency near the defect-induced E11* optical transition using a perturbative treatment of the electronic structure of the system. The obtained insights establish relationships between the nanotube atomistic structure and Raman spectra facilitating further exploration of SWCNTs with tunable optical properties tuned by chemical functionalization.
This paper examines if, when, and to what extent multinational tax incentives incrementally explain where firms move offshored U.S. jobs. Using jobs data from a Department of Labor program called ...Trade Adjustment Assistance, I find a significant association between tax incentives and both the likelihood that a foreign country hosts offshored U.S. jobs and the number of U.S. jobs it hosts. This association is stronger when managers have discretion to coordinate cross-border transactions internally and when they do not face political costs imposed by labor unions. Following instances of offshoring, I find some evidence that offshoring firms have lower effective tax rates, but these reductions are concentrated within larger layoffs in which jobs are sent to low-tax countries. These findings are relevant to understanding the real effects and welfare consequences of incentives created by current U.S. tax policy.
We assessed whether 10-s sprint interval training (SIT) bouts with 2 or 4 min recovery periods can improve aerobic and anaerobic performance. Subjects (
n
= 48) were assigned to one of four groups ...exercise time (s):recovery time (min): (1) 30:4, (2) 10:4, (3) 10:2 or (4) control (no training). Training was cycling 3 week
−1
for 2 weeks (starting with 4 bouts session
−1
, increasing 1 bout every 2 sessions, 6 total). Pre- and post-training measures included:
V
O
2max
, 5-km time trial (TT), and a 30-s Wingate test. All groups were similar pre-training and the control group did not change over time. The 10-s groups trained at a higher intensity demonstrated by greater (
P
< 0.05) reproducibility of peak (10:4 = 96%; 10:2 = 95% vs. 30:4 = 89%), average (10:4 = 84%; 10:2 = 82% vs. 30:4 = 58%), and minimum power (10:4 = 73%; 10:2 = 69%; vs. 30:4 = 40%) within each session while the 30:4 group performed ~2
X
(
P
< 0.05) the total work session
−1
(83–124 kJ, 4–6 bouts) versus 10:4 (38–58 kJ); 10:2 (39–59 kJ). Training increased TT performance (
P
< 0.05) in the 30:4 (5.2%), 10:4 (3.5%), and 10:2 (3.0%) groups.
V
O
2max
increased in the 30:4 (9.3%) and 10:4 (9.2%), but not the 10:2 group. Wingate peak power kg
−1
increased (
P
< 0.05) in the 30:4 (9.5%), 10:4 (8.5%), and 10:2 (4.2%). Average Wingate power kg
−1
increased (
P
< 0.05) in the 30:4 (12.1%) and 10:4 (6.5%) groups. These data indicate that 10-s (with either 2 or 4 min recovery) and 30-s SIT bouts are effective for increasing anaerobic and aerobic performance.
The Opioid Crisis and the Orthopedic Surgeon Trasolini, Nicholas A.; McKnight, Braden M.; Dorr, Lawrence D.
The Journal of arthroplasty,
November 2018, 2018-11-00, 20181101, Volume:
33, Issue:
11
Journal Article
Peer reviewed
Opioid use and abuse has become a national crisis in the United States. Many opioid abusers become addicted through an initial course of legal, physician-prescribed medications. Consequently, there ...has been increased pressure on medical care providers to be better stewards of these medications. In orthopedic surgery and total joint arthroplasty, pain control after surgery is critical for restoring mobility and maintaining patient satisfaction in the early postoperative period. Before the opioid misuse epidemic, orthopedic surgeons were frequently influenced to “treat pain with pain medications.” Long-acting opioids, such as OxyContin were used commonly. In the past decade, there has been a paradigm shift in favor of multimodal pain control with limited opioid use. This review will discuss 4 major topics. First, we will describe the pressures on orthopedic surgeons to prescribe narcotic pain medications. We will then discuss the major and minor complications and side effects associated with these prescriptions. Second, we will review how these factors motivated the development of alternative pain management strategies and a multimodal approach. Third, we will look at perioperative interventions that can reduce postoperative opioid consumption, including wound injections and peripheral nerve blocks, which have shown superb clinical results. Finally, we will recommend an evidence-based program that avoids parenteral narcotics and facilitates rapid discharge home without readmissions for pain-related complaints.
IRS Attention BOZANIC, ZAHN; HOOPES, JEFFREY L.; THORNOCK, JACOB R. ...
Journal of accounting research,
March 2017, Volume:
55, Issue:
1
Journal Article
Peer reviewed
We study how public and private disclosure requirements interact to influence both tax regulator enforcement and firm disclosure. To capture IRS enforcement activities, we introduce a novel data set ...of IRS acquisition of firms' public financial disclosures, which we label IRS attention. We examine the implementation of two new disclosure requirements that potentially alter IRS attention: FIN 48, which increased public tax disclosure requirements, and Schedule UTP, which increased private tax disclosure. We find that IRS attention increased following FIN 48 but subsequently decreased following Schedule UTP, consistent with public and private disclosure interacting to influence tax enforcement. We next examine how private tax disclosure requirements under Schedule UTP affected firms' public disclosure responses. We find that, following Schedule UTP, firms significantly increased the quantity and altered the content of their tax-related disclosures, consistent with lower tax-related proprietary costs of disclosure. Our results suggest that changes in SEC disclosure requirements altered the IRS's behavior with regard to public information acquisition, and, relatedly, changes in IRS private disclosure requirements appear to change firms' public disclosure behavior.
Coupling molecules to the quantized radiation field inside an optical cavity creates a set of new photon–matter hybrid states called polariton states. We combine electronic structure theory with ...quantum electrodynamics (QED) to investigate molecular polaritons using ab initio simulations. This framework joins unperturbed electronic adiabatic states with the Fock state basis to compute the eigenstates of the QED Hamiltonian. The key feature of this “parametrized QED” approach is that it provides the exact molecule–cavity interactions, limited by only approximations made in the electronic structure. Using time-dependent density functional theory, we demonstrated comparable accuracy with QED coupled cluster benchmark results for predicting potential energy surfaces in the ground and excited states and showed selected applications to light-harvesting and light-emitting materials. We anticipate that this framework will provide a set of general and powerful tools that enable direct ab initio simulation of exciton polaritons in molecule–cavity hybrid systems.
The stability of a total hip arthroplasty relies on proper positioning of the acetabular cup. Recent research has shown that this cup position is more dynamic than previously thought. The ...3-dimensional orientation of the acetabular cup changes when the pelvis tilts anteriorly or posteriorly. These changes in pelvic tilt are directly related to the biomechanics of the lumbosacral junction. In normal physiology, the lumbar spine straightens with sitting and becomes more lordotic with standing. This directly translates to posterior or anterior pelvic tilt due to the rigid sacroiliac attachments. During sitting, increased posterior pelvic tilt opens the acetabulum to accommodate flexion and internal rotation of the hip. This helps prevent anterior impingement and posterior hip dislocation. During standing, anterior pelvic tilt increases superior coverage of the acetabulum. This helps prevent posterior impingement and anterior hip dislocations. When lumbosacral motion becomes pathologic, spinopelvic motion changes and acetabular cup orientation is affected. In cases of decreased lumbosacral motion, patients rely on greater hip motion to reach standing or sitting positions. This can cause pathologic impingement. In addition, traditional safe zones for cup position may not apply in the presence of pathologic spinopelvic motion. This article discusses the normal physiology of spinopelvic motion, the patterns of pathologic change, and the clinical implications therein.
Formation of the sp3-defect due to covalent functionalization of a single-walled carbon nanotube (SWCNT) results in a new red-shifted emissive excitons. Using density functional theory, we study the ...impact of the intrinsic molecular dipole moments and the local charges induced by various molecular adducts on the energy and localization properties of the optically active defect-based exciton in a (10,5) SWCNT. The interplay of two effects plays a role in the localization of the exciton and, therefore, its red shift, but at different scales: The source of the leading order contribution is the defect conformation, resulting in the red shift of the defect-associated exciton with respect to the E11 band of the pristine SWCNT on the order of ∼100 meV, while the individual dipoles and polarization properties of molecular adducts lead to significantly smaller red shifts on the order of ∼10 meV. While the species-dependent trends in defect-induced charges do not directly correlate to the exciton red shift, the charge at the sp3-defect exhibits a distinct behavior between ortho- and para-defect configurations and is relevant to the chemical reactivity of the defect position depending on the adduct type. Overall, our computational results may be helpful for diverse synthetic strategies to fine-tune emission of SWCNTs toward desired applications.
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