Optical vortex generation from molecular chromophore arrays

The generation of light endowed with orbital angular momentum, frequently termed optical vortex light, is commonly achieved by passing a conventional beam through suitably constructed optical elements. This Letter shows that the necessary phase structure for vortex propagation can be directly produced through the creation of twisted light from the vacuum. The mechanism is based on optical emission from a family of chromophore nanoarrays that satisfy specific geometric and symmetry constraints. Each such array can support pairs of electronically delocalized doubly degenerate excitons whose azimuthal phase progression is responsible for the helical wave front of the emitted radiation. The exciton symmetry dictates the maximum magnitude of topological charge; detailed analysis secures the conditions necessary to deliver optical vortices of arbitrary order

Financial hardship and psychological distress: Exploring the buffering effects of religion

Despite ample precedent in theology and social theory, few studies have systematically examined the role of religion in mitigating the harmful effects of socioeconomic deprivation on mental health. The present study outlines several arguments linking objective and subjective measures of financial hardship, as well as multiple aspects of religious life, with psychological distress. Relevant hypotheses are then tested using data on adults aged 18–59 from the 1998 US NORC General Social Survey. Findings confirm that both types of financial hardship are positively associated with distress, and that several different aspects of religious life buffer against these deleterious influences. Specifically, religious attendance and the belief in an afterlife moderate the deleterious effects of financial hardship on both objective and subjective financial hardship, while meditation serves this function only for objective hardship. No interactive relationships were found between frequency of prayer and financial hardship. A number of implications, study limitations, and directions for future research are identified

Maternal Knowledge, Attitudes, and Practices Concerning Interpregnancy Interval

Introduction. Few studies have examined maternal intentions andpractices related to interpregnancy interval (IPI). IPI less than 18months has been linked to increased preterm birth and infant mortality.This manuscript reports on a cross-sectional survey of mothersconducted to understand maternal knowledge, attitudes, and practiceof IPI in Sedgwick County, Kansas. Methods. New and expectant mothers and mothers of neonatalinfant care unit (NICU) graduates (n = 125) were surveyed regardingthe issues surrounding IPI. Front desk staff handed out self-administeredsurveys, which were returned to a nurse upon completion.NICU participants were emailed a link to the survey hosted on SurveyMonkey®. Results. Fewer than 30% of mothers reported previously receivinginformation about IPI from any source. When asked about risks associatedwith IPI, women frequently (n = 58, 45%) identified increasedrisk for birth outcomes with no known association with short IPI.Findings regarding maternal attitudes surrounding optimal IPI weremixed with many mothers defining ideal IPI as less than 18 months(n = 52, 42%), while broadly reporting they believed that a woman’sbody needs time to heal between pregnancies. Respondents from theNICU sample generally reported shorter optimal IPI values than theother participants. When IPI was estimated from participants’ pastpregnancies, half of IPIs were less than 18 months. Mothers reportedthey favored healthcare providers as a source for IPI education. Faceto-face discussions or printed materials were the preferred modes ofeducation. Conclusions. Women were aware of the need for spacing betweenpregnancies, however, that knowledge was unassociated with pastbehavior. These findings should be taken into consideration whenformulating future interventions. Kans J Med 2018;11(4):86-90

Attachment to God, Images of God, and Psychological Distress in a Nationwide Sample of Presbyterians

Drawing broadly on insights from attachment theory, the present study outlines a series of theoretical arguments linking styles of attachment to God, perceptions of the nature of God (i.e., God imagery), and stressful life events with psychological distress. Main effects and potential stress-moderator effects are then evaluated using data from a nationwide sample of elders and rank-and-file members of the Presbyterian Church (U.S.A.). Key findings indicate that secure attachment to God is inversely associated with distress, whereas both anxious attachment to God and stressful life events are positively related to distress. Once variations in patterns of attachment to God are controlled, there are no net effects of God imagery on levels of distress. There is only modest support for the hypothesis that God images moderate the effects of stressful life events on psychological distress, but no stress-moderator effects were found for attachment to God. Study limitations are identified, and findings are discussed in terms of their implications for religion-health research, as well as recent extensions of attachment theory

Spiritual and religious identities predict the use of complementary and alternative medicine among US adults

To determine whether spiritual and religious identities predict CAM use above and beyond other known influences such as gender, region of residence, social status, personality, health, and access to conventional medicine

Transcendent Accountability and Pro-Community Attitudes: Assessing the Link Between Religion and Community Engagement

Prior research has established a positive relationship between religiosity and civic engagement but focused on public religiosity rather than private religiosity without explaining the relationship. We examined private religiosity as well as public religiosity in relation to community engagement, explaining the religiosity-community engagement relationship with two understudied mechanisms: ‘‘transcendent accountability’’ (seeing oneself as accountable to God or a higher power for one’s influence on other people or the environment) and pro-community attitudes. For this examination, we applied structural equation modeling to analyze data from a nationally representative survey. We found that survey respondents who believed in a higher power, privately practiced devotional prayer and study of religious texts, and attended religious group activities (other than worship services), were more likely to report transcendent accountability to a higher power for their influence on other people and the environment. We also found that transcendent accountability was related positively to pro-community attitudes, which in turn was positively associated with community engagement. The indirect relationships between religiosity and community engagement were mostly significant. In conclusion, both private and public religious behaviors are consequential in the religiosity-civic engagement relationship, and the religiosity-linked virtue of transcendent accountability and its associated pro-community attitudes contribute to civic engagement

Direct generation of optical vortices

A detailed scheme is established for the direct generation of optical vortices, signifying light endowed with orbital angular momentum. In contrast to common techniques based on the tailored conversion of the wave front in a conventional beam, this method provides for the direct spontaneous emission of photons with the requisite field structure. This form of optical emission results directly from the electronic relaxation of a delocalized exciton state that is supported by a ringlike array of three or more nanoscale chromophores. An analysis of the conditions leads to a general formulation revealing a requirement for the array structure to adhere to one of a restricted set of permissible symmetry groups. It is shown that the coupling between chromophores within each array leads to an energy level splitting of the exciton structure, thus providing for a specific linking of exciton phase and emission wavelength. For emission, arrays conforming to one of the given point-group families’ doubly degenerate excitons exhibit the specific phase characteristics necessary to support vortex emission. The highest order of exciton symmetry, corresponding to the maximum magnitude of electronic orbital angular momentum supported by the ring, provides for the most favored emission. The phase properties of the emission produced by the relaxation of such excitons are exhibited on plots which reveal the azimuthal phase progression around the ring, consistent with vortex emission. It is proven that emission of this kind produces electromagnetic fields that map with complete fidelity onto the phase structure of a Laguerre-Gaussian optical mode with the corresponding topological charge. The prospect of direct generation paves the way for practicable devices that need no longer rely on the modification of a conventional laser beam by a secondary optical element. Moreover, these principles hold promise for the development of a vortex laser, also based on nanoscale exciton decay, enabling the production of coherent radiation with a tailor-made helical wave front

Perturbation theory and the two-level approximation:A corollary and critique

This analysis addresses the use of a two-level approximation to simplify expressions derived from perturbation theory. It is shown that the limitations of validity for the emergent results are more stringent than is commonly understood, being equivalent in effect to the adoption of a more extensive approximation - one that significantly undermines the perturbative origin of those expressions. Effectively truncating the completeness relation, a series of interconnected operator relations comes into play, some with physically untenable consequences. A new theorem on the expectation values of operator functions highlights additional constraints upon any molecule modelled as a two-level system. © 2010 Elsevier B.V. All rights reserved

The broad band X-ray/hard X-ray spectra of accreting neutron stars

I review the energy spectra of low mass X-ray binaries (LMXBs) containing weakly magnetized accreting neutron stars (NS), emphasizing the most recent broad band (0.1-200 keV) spectral and timing observations performed by Beppo-SAX and RXTE. Drawing on the similarities between black hole candidate (BHC) and NS accretion, I discuss the accretion geometry and emission processes of NS LMXBs.Comment: 15 pages, 17 figures, Invited review at the 33rd COSPAR Scientific Assembly, Warsaw, Poland, July, 2000. Accepted for publication in Advances in Space Research. The paper is also available from http://www.cesr.fr/~barret

Brass Happenings

Presenting a student recital for brass students in USU\u27s Music Department.https://digitalcommons.usu.edu/music_programs/1107/thumbnail.jp