The role of intermolecular coupling in the photophysics of disordered organic semiconductors: Aggregate emission in regioregular polythiophene

We address the role of excitonic coulping on the nature of photoexcitations in the conjugated polymer regioregular poly(3-hexylthiophene). By means of temperature-dependent absorption and photoluminescence spectroscopy, we show that optical emission is overwhelmingly dominated by weakly coupled H-aggregates. The relative absorbance of the 0-0 and 0-1 vibronic peaks provides a powerfully simple means to extract the magnitude of the intermolecular coupling energy, approximately 5 and 30 meV for films spun from isodurene and chloroform solutions respectively.Comment: 10 pages, 4 figures, published in Phys. Rev. Let

The Design and Validation of the Quantum Mechanics Conceptual Survey

The Quantum Mechanics Conceptual Survey (QMCS) is a 12-question survey of students' conceptual understanding of quantum mechanics. It is intended to be used to measure the relative effectiveness of different instructional methods in modern physics courses. In this paper we describe the design and validation of the survey, a process that included observations of students, a review of previous literature and textbooks and syllabi, faculty and student interviews, and statistical analysis. We also discuss issues in the development of specific questions, which may be useful both for instructors who wish to use the QMCS in their classes and for researchers who wish to conduct further research of student understanding of quantum mechanics. The QMCS has been most thoroughly tested in, and is most appropriate for assessment of (as a posttest only), sophomore-level modern physics courses. We also describe testing with students in junior quantum courses and graduate quantum courses, from which we conclude that the QMCS may be appropriate for assessing junior quantum courses, but is not appropriate for assessing graduate courses. One surprising result of our faculty interviews is a lack of faculty consensus on what topics should be taught in modern physics, which has made designing a test that is valued by a majority of physics faculty more difficult than expected.Comment: Submitted to Physical Review Special Topics: Physics Education Researc

Understanding the Relationships between Tourists’ Emotional Experiences, Perceived Overall Image, Satisfaction, and Intention to Recommend

The purpose of this study is to empirically test an integrative model linking tourists' emotional experiences, perceived overall image, satisfaction, and intention to recommend. The model was tested using data collected from domestic tourists visiting Sardinia, Italy. Results show that tourists' emotional experiences act as antecedents of perceived overall image and satisfaction evaluations. In addition, overall image has a positive influence on tourist satisfaction and intention to recommend. The study expands current theorizations by examining the merits of emotions in tourist behavior models. From a practical perspective, the study offers important implications for destination marketers

Unconditional care in academic emergency departments

Recent news stories have explicitly stated that patients with symptoms of COVID-19 were "turned away" from emergency departments. This commentary addresses these serious allegations, with an attempt to provide the perspective of academic emergency departments (EDs) around the Nation. The overarching point we wish to make is that academic EDs never deny emergency care to any person

Gender-dependent differences in plasma matrix metalloproteinase-8 elevated in pulmonary tuberculosis.

Tuberculosis (TB) remains a global health pandemic and greater understanding of underlying pathogenesis is required to develop novel therapeutic and diagnostic approaches. Matrix metalloproteinases (MMPs) are emerging as key effectors of tissue destruction in TB but have not been comprehensively studied in plasma, nor have gender differences been investigated. We measured the plasma concentrations of MMPs in a carefully characterised, prospectively recruited clinical cohort of 380 individuals. The collagenases, MMP-1 and MMP-8, were elevated in plasma of patients with pulmonary TB relative to healthy controls, and MMP-7 (matrilysin) and MMP-9 (gelatinase B) were also increased. MMP-8 was TB-specific (p<0.001), not being elevated in symptomatic controls (symptoms suspicious of TB but active disease excluded). Plasma MMP-8 concentrations inversely correlated with body mass index. Plasma MMP-8 concentration was 1.51-fold higher in males than females with TB (p<0.05) and this difference was not due to greater disease severity in men. Gender-specific analysis of MMPs demonstrated consistent increase in MMP-1 and -8 in TB, but MMP-8 was a better discriminator for TB in men. Plasma collagenases are elevated in pulmonary TB and differ between men and women. Gender must be considered in investigation of TB immunopathology and development of novel diagnostic markers

Detection, Estimation, and Modulation Theory

Contains research objectives and summary of research on four research projects.Joint Services Electronics Program (Contract DAAB07-75-C-1346)Woods Hole Oceanographic Institution Purchase Order 455

Caenorhabditis elegans Show Preference for Stimulants and Potential as a Model Organism for Medications Screening

The nematode Caenorhabditis elegans (C. elegans) is a popular invertebrate model organism to study neurobiological disease states. This is due in part to the intricate mapping of all neurons and synapses of the entire animal, the wide availability of mutant strains, and the genetic and molecular tools that can be used to manipulate the genome and gene expression. We have shown that, C. elegans develops a conditioned preference for cues that had previously been paired with either cocaine or methamphetamine exposure that is dependent on dopamine neurotransmission, similar to findings using place conditioning with rats and mice. In the current study, we show C. elegans also display a preference for, and self-exposure to, cocaine and nicotine. This substance of abuse (SOA) preference response can be selectively blocked by pretreatment with naltrexone and is consistent with the recent discovery of an opioid receptor system in C. elegans. In addition, pre-exposure to the smoking cessation treatment varenicline also inhibits self-exposure to nicotine. Exposure to concentrations of treatments that inhibit SOA preference/self-exposure did not induce any significant inhibition of locomotor activity or affect food or benzaldehyde chemotaxis. These data provide predictive validity for the development of high-throughput C. elegans behavioral medication screens. These screens could enable fast and accurate generation of data to identify compounds that may be effective in treating human addiction. The successful development and validation of such models would introduce powerful and novel tools in the search for new pharmacological treatments for substance use disorders, and provide a platform to study the mechanisms that underlie addictions

Reconfiguration, contestation, and decline: conceptualizing mature large technical systems

Large technical systems (LTS) are integral to modern lifestyles but arduous to analyze. In this paper, we advance a conceptualization of LTS using the notion of mature “phases,” drawing from insights into innovation studies, science and technology studies, political science, the sociology of infra- structure, history of technology, and governance. We begin by defining LTS as a unit of analysis and explaining its conceptual utility and novelty, situating it among other prominent sociotechnical theories. Next, we argue that after LTS have moved through the (overlapping) phases proposed by Thomas Hughes of invention, expansion, growth, momentum, and style,mature LTS undergo the additional (overlapping) phases of reconfiguration, contestation (subject to pressures such as drift and crisis), and eventually stagnation and decline. We illustrate these analytical phases with historical case studies and the conceptual literature, and close by suggesting future research to refine and develop the LTS framework, particularly related to more refined typologies, temporal dimensions, and a broadening of system users. We aim to contribute to theoretical debates about the coevolution of LTS as well as empirical discussions about system-related use, socio- technical change, and policy-making

Observation of strong electromagnetic fields around laser-entrance holes of ignition-scale hohlraums in inertial-confinement fusion experiments at the National Ignition Facility

Energy spectra and spectrally resolved one-dimensional fluence images of self-emitted charged-fusion products (14.7 MeV D[superscript 3]He protons) are routinely measured from indirectly driven inertial-confinement fusion (ICF) experiments utilizing ignition-scaled hohlraums at the National Ignition Facility (NIF). A striking and consistent feature of these images is that the fluence of protons leaving the ICF target in the direction of the hohlraum's laser entrance holes (LEHs) is very nonuniform spatially, in contrast to the very uniform fluence of protons leaving through the hohlraum equator. In addition, the measured nonuniformities are unpredictable, and vary greatly from shot to shot. These observations were made separately at the times of shock flash and of compression burn, indicating that the asymmetry persists even at ~0.5–2.5 ns after the laser has turned off. These phenomena have also been observed in experiments on the OMEGA laser facility with energy-scaled hohlraums, suggesting that the underlying physics is similar. Comprehensive data sets provide compelling evidence that the nonuniformities result from proton deflections due to strong spontaneous electromagnetic fields around the hohlraum LEHs. Although it has not yet been possible to uniquely determine whether the fields are magnetic (B) or electric (E), preliminary analysis indicates that the strength is ~1 MG if B fields or ~10[superscript 9] V cm[superscript −1] if E fields. These measurements provide important physics insight into the ongoing ignition experiments at the NIF. Understanding the generation, evolution, interaction and dissipation of the self-generated fields may help to answer many physics questions, such as why the electron temperatures measured in the LEH region are anomalously large, and may help to validate hydrodynamic models of plasma dynamics prior to plasma stagnation in the center of the hohlraum.United States. Dept. of Energy (DE-FG52-07 NA280 59)United States. Dept. of Energy (DE-FG03-03SF22691)Lawrence Livermore National Laboratory (B543881)Lawrence Livermore National Laboratory (LD RD-08-ER-062)University of Rochester. Fusion Science Center (412761-G)General Atomics (DE-AC52-06NA 27279)Stewardship Science Graduate Fellowship (DE-FC52-08NA28752

Sociodemographic and Disease Correlates of Body Image Distress among Patients with Systemic Sclerosis

Body image concerns are infrequently studied in systemic sclerosis (SSc), even though significant visible disfigurement is common. The objective of this study was to identify sociodemographic and disease-related correlates of dissatisfaction with appearance and social discomfort among people with SSc.SSc patients came from the 15-center Canadian Scleroderma Research Group Registry. Sociodemographic information was based on patient self-report. Disease characteristics were obtained via physician examinations. The Brief-SWAP was used to assess dissatisfaction with appearance and social discomfort. Structural equation models were conducted with MPlus to determine the relationship of dissatisfaction with appearance and social discomfort with age, sex, education, marital status, race/ethnicity, disease duration, skin involvement, telangiectasias, skin pigmentation changes, and hand contractures.A total of 489 SSc patients (432 female, 57 male) were included. Extent of skin involvement was significantly associated with both dissatisfaction with appearance and social discomfort (standardized regression coefficients = 0.02, p = 0.001; 0.02, p = 0.020, respectively), as was skin involvement in the face (0.18, p = 0.016; 0.23, p = 0.006, respectively). Greater social discomfort was robustly associated with younger age (-0.017, p<0.001) and upper-body telangiectasias (0.32, p = 0.021). Dissatisfaction with appearance was associated with hand contractures (0.07, p = 0.036).This study found that dissatisfaction with appearance and social discomfort were associated with numerous disfiguring characteristics of SSc, in addition to age. These results underline that there are multiple factors contributing to body image distress in SSc, as well as the need to attend to both disease and social contexts in understanding the impact of disfigurement among patients