Light-matter interactions

Understanding light-matter interaction is important to control the electron and nuclear dynamics of quantum-mechanical systems. The present work investigates this in the form of angular dependent tunnel ionization and different control mechanisms for nuclear, electron and coupled dynamics. With the help of close collaboration with experimental groups several control mechanisms could be examined and explained. The refined methods and models for these studies can be expanded for different experiments or more general concepts. The first part of this thesis focuses on tunnel ionization as one of the fundamental quantum-mechanical light-matter interactions while the second and third part investigates the control of nuclear and electron dynamics in depth. The angular dependent tunnel ionization of small hydrocarbons and the impact of their field dressed orbitals are researched in chapter 3. Advanced quantum chemical methods are used to explain experimental findings that could not be recognized by only looking at the Highest Occupied Molecular Orbital (HOMO). The so studied molecules show the importance to consider field dressed instead of field free orbitals to understand the light-matter interaction, to replicate experimental findings with theoretical models and to predict the behavior of different molecules. The influence of Rydberg character in virtual orbitals, that can become populated in a field dressed picture, can explain the difference in the angular dependent tunnel ionization for two similar derivates of Cyclohexadiene (CHD) and the lobed structure for C2H4 . This chapter also shows the success of adapting a previous used model for diatomic systems to polyatomic systems. The second part (chapter 4) investigates the deprotonation and isomerization reaction of acetylene (C2H2) and allene (C3H4) and the potential control with laser pulses over theses reaction. The first control mechanism utilizes the light field to suppress the reaction barrier, which allows molecules with lower energy to undergo isomerization and therefore increase the rate of the reaction. The second scheme controls the asymmetry of the reaction, so that either the left to right or right to left isomerization is preferred. This control is exercised by directly manipulating the nuclear wave packet with the Carrier–Envelope–Phase (CEP) of the laser pulse. The mechanism relies on forming a superposition of different normal modes that are excited by different means and therefore have a phase difference. One or more normal modes are excited by the light field and get the CEP imprinted in their phase while the other important normal modes are indirectly excited by the ionization process. This enables directional control of the nuclear dynamics in symmetric molecules. The concept of forming the superposition is general enough to be used in different reactions and molecules. In the last part (chapter 5) the control of electron dynamics with laser pulses is studied. The test case is the selective population of dressed states (SPODS) in the potassium dimer (K2). There a first pulse will populate an electronic superposition between the ground and first excited state. Depending on the relative phase of the second pulse to the oscillating dipole created by the electronic wave packet, the upper or lower dressed state will be populated. Excitation from the two different dressed states leads to two distinguishable final states. Although the scheme focuses on the control of the electron dynamics, the whole mechanism is also heavily influenced by the associated nuclear dynamics

Light-matter interactions

Understanding light-matter interaction is important to control the electron and nuclear dynamics of quantum-mechanical systems. The present work investigates this in the form of angular dependent tunnel ionization and different control mechanisms for nuclear, electron and coupled dynamics. With the help of close collaboration with experimental groups several control mechanisms could be examined and explained. The refined methods and models for these studies can be expanded for different experiments or more general concepts. The first part of this thesis focuses on tunnel ionization as one of the fundamental quantum-mechanical light-matter interactions while the second and third part investigates the control of nuclear and electron dynamics in depth. The angular dependent tunnel ionization of small hydrocarbons and the impact of their field dressed orbitals are researched in chapter 3. Advanced quantum chemical methods are used to explain experimental findings that could not be recognized by only looking at the Highest Occupied Molecular Orbital (HOMO). The so studied molecules show the importance to consider field dressed instead of field free orbitals to understand the light-matter interaction, to replicate experimental findings with theoretical models and to predict the behavior of different molecules. The influence of Rydberg character in virtual orbitals, that can become populated in a field dressed picture, can explain the difference in the angular dependent tunnel ionization for two similar derivates of Cyclohexadiene (CHD) and the lobed structure for C2H4 . This chapter also shows the success of adapting a previous used model for diatomic systems to polyatomic systems. The second part (chapter 4) investigates the deprotonation and isomerization reaction of acetylene (C2H2) and allene (C3H4) and the potential control with laser pulses over theses reaction. The first control mechanism utilizes the light field to suppress the reaction barrier, which allows molecules with lower energy to undergo isomerization and therefore increase the rate of the reaction. The second scheme controls the asymmetry of the reaction, so that either the left to right or right to left isomerization is preferred. This control is exercised by directly manipulating the nuclear wave packet with the Carrier–Envelope–Phase (CEP) of the laser pulse. The mechanism relies on forming a superposition of different normal modes that are excited by different means and therefore have a phase difference. One or more normal modes are excited by the light field and get the CEP imprinted in their phase while the other important normal modes are indirectly excited by the ionization process. This enables directional control of the nuclear dynamics in symmetric molecules. The concept of forming the superposition is general enough to be used in different reactions and molecules. In the last part (chapter 5) the control of electron dynamics with laser pulses is studied. The test case is the selective population of dressed states (SPODS) in the potassium dimer (K2). There a first pulse will populate an electronic superposition between the ground and first excited state. Depending on the relative phase of the second pulse to the oscillating dipole created by the electronic wave packet, the upper or lower dressed state will be populated. Excitation from the two different dressed states leads to two distinguishable final states. Although the scheme focuses on the control of the electron dynamics, the whole mechanism is also heavily influenced by the associated nuclear dynamics

Common Components of Fetal Alcohol Spectrum Disorder Prevention Intervention Programs: A Review of Literature

Abstract Background: Fetal alcohol spectrum disorders (FASD) are the most common yet completely preventable cause of mental disability in the western world. Objective: The purpose of this integrative literature review is to examine and identify the common elements among varying interventions for FASD prevention that have demonstrated effectiveness for reducing the risk of FASD to better understand what defining features may contribute to the efficacy of the interventions. Methods: An integrative literature review was conducted. The databases searched included: CINAHL, PubMed, Cochrane Library, and Science Direct. Articles were then reviewed to determine if they were appropriate for inclusion based upon content and inclusion criteria. Findings: Personalized feedback and education, establishment of a therapeutic relationship, replicable and standardized intervention procedures, and the inclusion of follow-up and continuous care are among the most significant elements shared between the interventions in the selected literature. Conclusion: The defining elements discussed in this review highlight crucial interventional components that provide a foundation for further research to explore and utilize, however much more research is needed to lower the high incidence of FASD. Keywords: pregnancy, alcohol, fetal alcohol spectrum disorders, alcohol exposed pregnancy, prevention, identification, and intervention

Riverside: A private equity acquisition

Treballs Finals del Màster en Oficial en Empresa Internacional / International Business, Facultat d'Economia i Empresa, Universitat de Barcelona, Curs: 2019-2020, Tutor: Martí SagarraPrivate equity (PE) boomed in the 2000’s, aligned with an increase in their debt levels. Traditionally, PE firms bought target companies using mostly debt to create short term growth and sell profitably. Nowadays,some PE firms transform their targets to create sustainable value. Yet, little work is published on leveraged buyouts (LBO) in the middle market with sustainable value creation for the target. The objective of this work is therefore to develop a real-world case study analyzing if a PE acquisition with LBO in the middle market fits the fund’s strategy for sustainable growth. This single case study was developed in Spain using qualitative and quantitative research conducted in 2020. The case studies the successful 2015 investment of the American PE firm Riverside in Euromed, a Spanish herbal extracts manufacturer. It shows that PE can benefit from sustainable improvement of a target company if all steps of an investment decision-making process are executed rigorously

Advertisement-financed credit ratings

This paper investigates the incentives of a credit rating agency (CRA) to generate accurate ratings under an advertisement-based business model. To this end, we study a two-period endogenous reputation model in which a CRA can increase the precision of its ratings by exerting effort. The CRA receives a revenue not from rating fees, as is standard in the literature, but through online advertising. We show that the advertisement-based business model provides sufficient incentives for the CRA to improve the precision of signals at intermediate levels of reputation. Furthermore, we identify conditions under which truthful reporting is incentive compatible. © 2021, The Author(s)

A Case for On-Site Occupational and Non-Occupational Health Care for Health Care Workers

The cost of health care in the United States is high and is expected to steadily increase. Hospitals and health care systems are affected by the rising costs in the form of expenditures on behalf of their employees' health care needs. Health care workers (HCWs) have higher utilization rates and carry a higher burden of chronic illness than employees in other market segments. Finding better ways to manage risk levels of these employees is critical to reducing costs. Current health care strategies include wellness programs and health conscious worksites. Many employers in an array of industries have instituted on-site primary care clinics to not only take care of minor acute illnesses but to provide management of chronic conditions for employees realizing that a healthy employee is a more productive employee. These clinics are a convenient way for employees to receive medical treatment without having to go too far from the worksite and, at the same time, offer an opportunity for the employee to learn about other health- related services covered under the employer's company plan. This paper addresses the special circumstance of the higher than average health care cost for HCWs, how this might be addressed, and to make a case for on-site urgent and primary care options utilizing the concepts of the patient-centered medical home model in addition to the presently offered employer-sponsored occupational health and wellness services. With such an integrated and comprehensive health care system comes an expanded role for occupational health nurses and occupational health nurse practitioners to join with other health care professionals in devising and implementing effective methods of improving patient outcomes. Key words: Workplace Medical Clinics, Primary Health Care for Health Care Workers, Occupational Health NursingMaster of Public Healt

Steering proton migration in hydrocarbons using intense few-cycle laser fields

Proton migration is a ubiquitous process in chemical reactions related to biology, combustion, and catalysis. Thus, the ability to control the movement of nuclei with tailored light, within a hydrocarbon molecule holds promise for far-reaching applications. Here, we demonstrate the steering of hydrogen migration in simple hydrocarbons, namely acetylene and allene, using waveform-controlled, few-cycle laser pulses. The rearrangement dynamics are monitored using coincident 3D momentum imaging spectroscopy, and described with a quantum-dynamical model. Our observations reveal that the underlying control mechanism is due to the manipulation of the phases in a vibrational wavepacket by the intense off-resonant laser field.Comment: 5 pages, 4 figure

An indelible lineage marker for Xenopus using a mutated green fluorescent protein

We describe the use of a DNA construct (named GFP.RN3) encoding green fluorescent protein as a lineage marker for Xenopus embryos. This offers the following advantages over other lineage markers so far used in Xenopus. When injected as synthetic mRNA, its protein emits intense fluorescence in living embryos. It is non-toxic, and the fluorescence does not bleach when viewed under 480 nm light. It is surprisingly stable, being strongly visible up to the feeding tadpole stage (5 days), and in some tissues for several weeks after mRNA injection. We also describe a construct that encodes a blue fluorescent protein. We exemplify the use of this GFP.RN3 construct for marking the lineage of individual blastomeres at the 32- to 64-cell stage, and as a marker for single transplanted blastula cells. Both procedures have revealed that the descendants of one embryonic cell can contribute single muscle cells to nearly all segmental myotomes rather than predominantly to any one myotome. An independent aim of our work has been to follow the fate of cells in which an early regulatory gene has been temporarily overexpressed. For this purpose, we co-injected GFP.RN3 mRNA and mRNA for the early Xenopus gene Eomes, and found that a high concentration of Eomes results in ectopic muscle gene activation in only the injected cells. This marker may therefore be of general value in providing long term identification of those cells in which an early gene with ephemeral expression has been overexpressed