11,106 research outputs found
Radio-Excess IRAS Galaxies: IV. Optical Spectroscopy
This is the fourth in our series of papers investigating radio-excess
galaxies, which have radio emission associated with an active nucleus but which
do not fit into the traditional categories of either radio-loud or radio-quiet
active galaxies. In this paper, we present optical spectra of our sample of
FIR-luminous radio-excess galaxies. Optical emission line diagnostics are used
to determine the dominant source of the ionizing radiation. We find that radio
excess is an excellent indicator of the presence of an active nucleus: the
radio-excess sample contains a much higher fraction of AGN than samples
selected on FIR luminosity alone, or using other criteria such as warm FIR
colors. Several objects have ambiguous classifications and are likely to be
composite objects with mixed excitation. The type of optical spectrum appears
to be associated with the radio-loudness: radio-loud objects may be more `pure'
AGN than radio-intermediate objects. We find strong evidence for interaction
between the radio plasma and the surrounding gas. The jet energy fluxes of the
radio-excess objects, inferred from the [O III] luminosities, are lower than in
powerful radio sources, consistent with our previous results. We conclude that
the jets of radio-intermediate sources are intrinsically weaker than those in
sources with more powerful radio emission. A significant fraction of the sample
spectra show post-starburst stellar continuum, with A-star absorption lines,
consistent with the large fraction of merging or disturbed host galaxies in the
sample. The ages of the radio sources are significantly less than those of A
stars indicating that, if the radio sources are associated with merging
activity, there is a delay between the interaction and the initiation of the
radio activity. (Abridged.)Comment: Accepted for publication in AJ; version with high resolution figures
available from http://www.cis.rit.edu/~clbsps/papers/paper4.pd
EPR identification of defects responsible for thermoluminescence in Cu-doped lithium tetraborate (Li2B4O7) crystals
Electron paramagnetic resonance (EPR) is used to identify the electron and hole traps responsible for thermoluminescence (TL) peaks occurring near 100 and 200 ◦C in copper-doped lithium tetraborate (Li2B4O7) crystals. As-grown crystals have Cu+ and Cu2+ ions substituting for lithium and have Cu+ ions at interstitial sites. All of the substitutional Cu2+ ions in the as-grown crystals have an adjacent lithium vacancy and give rise to a distinct EPR spectrum. Exposure to ionizing radiation at room temperature produces a second and different Cu2+ EPR spectrum when a hole is trapped by substitutional Cu+ ions that have no nearby defects. These two Cu2+ trapped-hole centers are referred to as Cu2+-VLi and Cu2+active, respectively. Also during the irradiation, two trapped-electron centers in the form of interstitial Cu0 atoms are produced when interstitial Cu+ ions trap electrons. They are observed with EPR and are labeled Cu0A and Cu0B. When an irradiated crystal is warmed from 25 to 150 ◦C, the Cu2+active centers have a partial decay step that correlates with the TL peak near 100 ◦C. The concentrations of Cu0A and Cu0B centers, however, increase as the crystal is heated through this range. As the crystal is futher warmed between 150 and 250 ◦C, the EPR signals from the Cu2+active hole centers and Cu0A and Cu0B electron centers decay simultaneously. This decay step correlates with the intense TL peak near 200 ◦C
Community Strengths and Challenges Related to Opioid Use Disorder in Rural Counties of East Tennessee
Introduction: Appalachia, particularly Rural East Tennessee, has been and continues to be disproportionately impacted by opioid use disorder and its many tragic ramifications.
Purpose: Community-engaged strategies can inform and support the development of relevant prevention efforts. Hence, people connected to a ten-county rural Appalachian region in East Tennessee were asked to identify and prioritize strengths and challenges related to opioid use disorder (OUD).
Methods: Adult community members (n=577) completed a brief survey administered across 11 days in 2019.
Results: Of the respondents, 85.3% never had been addicted to opioids, but 74.0% had someone close to them with OUD. The most frequently selected community strength was support for people with OUD to seek help and the most frequently selected challenge was lack of treatment and recovery services. People with personal OUD experience reported significantly higher mean levels of OUD-related stigma compared to persons without such experience.
Implications: The number of respondents indicates a local concern and commitment related to OUD in rural Appalachia. The findings prioritized areas of focus—both in needs to be addressed and strengths on which to capitalize. These community insights will guide the selection and development of OUD-related overdose prevention for this region
When you are homeless, you are not thinking about your medication, but your food, shelter or heat for the night: behavioural determinants of homeless patients' adherence to prescribed medicines.
Objectives This study aimed to explore behavioural determinants of homeless patients' adherence to prescribed medicines using Theoretical Domains Framework (TDF). Study design A qualitative study using semi-structured, face-to-face interviews. Methods Participants were recruited from a homelessness primary healthcare centre in Aberdeen, United Kingdom (UK). Face-to-face interviews were audio-recorded and transcribed verbatim. Thematic analysis of the interview data was conducted using the Framework Approach based on the Theoretical Domains Framework. National Health Service ethical and Research and Development (R&D) approval was obtained. Results Twenty-five patients were interviewed, at which point data saturation was achieved. A total of 13 out of 14 Theoretical Domains Framework domains were identified that explained the determinants of adherence or non-adherence to prescribed medicines. These included: beliefs about consequences (e.g. non-adherence leading to poor health); goals of therapy (e.g. being a normal person with particular reference to methadone adherence); and environmental context and resources (e.g. stolen medicines and the lack of secure storage). Obtaining food and shelter was higher priority than access and adherence to prescribed medicines while being homeless. Conclusions Behavioural determinants of non-adherence identified in this study were mostly related to participants' homelessness and associated lifestyle. Results are relevant to developing behaviour change interventions targeting non-adherent homeless patients and to the education of healthcare professionals serving this vulnerable population
Testing the Rule with Exclusive Semi-Leptonic Kaon Decays
We consider the possibility of violations of the selection rule at an appreciable level in {\it exclusive} semi-leptonic decays of
Kaons. At -Factories, intense Kaon beams will be available and will probe
among others, the semi-leptonic decays and in addition
to and could provide novel testing grounds for the
rule. In particular, the branching ratio of is non-negligible
and could be used to probe new phenomena associated with the violation of this
selection rule. Furthermore, we modify certain di-lepton event rate ratios and
asymmetries and time asymmetries that have been constructed by Dass and Sarma
for di-lepton events from Beon decays to test the at the
, to the Kaon system at the . We find that the large
width of the relative to that of plays an important role in
enhancing some of the time asymmetries.Comment: 10 pages, Plain Latex, To be run twice
Effects of Varying Proportions of Glass on Reflectance Spectra of HED Polymict Breccias
Some meteorites contain significant amounts of glass, which, in most cases, probably results from impact processes on parent bodies.. Yamato 82202 is an example of one of the unequilibrated eucrites that contains significant proportions of impact glass distributed as veins throughout the meteorite. In other cases, fragments of glass are distributed throughout polymict breccias. For example, the polymict eucrite EET 87509 contains rare angular fragments of devitrified glass. Proportions of glass in most of these meteorites and in lithic clasts within these meteorites may vary locally from small amounts (less than one percent) to much larger amounts (subequal proportions of glass and mineral material). For example, some fragments within the South African polymict eucrite Macibini contain approximately 50% glass. The presence of these variable proportions of meteorite glass confirm the increased recognition that impact processes played an important role in the histories of asteroidal bodies. This study attempts to quantify the effects of a glass component on reflectance spectra by analyzing in the laboratory mixtures of varying proportions of a well-characterized HED polymict breccia and glass derived by melting a bulk sample of that breccia
Effect of Disorder Strength on Optimal Paths in Complex Networks
We study the transition between the strong and weak disorder regimes in the
scaling properties of the average optimal path in a disordered
Erd\H{o}s-R\'enyi (ER) random network and scale-free (SF) network. Each link
is associated with a weight , where is a
random number taken from a uniform distribution between 0 and 1 and the
parameter controls the strength of the disorder. We find that for any
finite , there is a crossover network size at which the transition
occurs. For the scaling behavior of is in the
strong disorder regime, with for ER networks and
for SF networks with , and for SF networks with . For the scaling behavior is in the weak disorder regime, with for ER networks and SF networks with . In order to
study the transition we propose a measure which indicates how close or far the
disordered network is from the limit of strong disorder. We propose a scaling
ansatz for this measure and demonstrate its validity. We proceed to derive the
scaling relation between and . We find that for ER
networks and for SF networks with , and for SF networks with .Comment: 6 pages, 6 figures. submitted to Phys. Rev.
- …