430 research outputs found
Effects of circadian rhythm phase alteration on physiological and psychological variables: Implications to pilot performance (including a partially annotated bibliography)
The effects of environmental synchronizers upon circadian rhythmic stability in man and the deleterious alterations in performance and which result from changes in this stability are points of interest in a review of selected literature published between 1972 and 1980. A total of 2,084 references relevant to pilot performance and circadian phase alteration are cited and arranged in the following categories: (1) human performance, with focus on the effects of sleep loss or disturbance and fatigue; (2) phase shift in which ground based light/dark alteration and transmeridian flight studies are discussed; (3) shiftwork; (4)internal desynchronization which includes the effect of evironmental factors on rhythmic stability, and of rhythm disturbances on sleep and psychopathology; (5) chronotherapy, the application of methods to ameliorate desynchronization symptomatology; and (6) biorythm theory, in which the birthdate based biorythm method for predicting aircraft accident susceptability is critically analyzed. Annotations are provided for most citations
On the discovery of doubly-magic Ni
The paper reports on the first observation of doubly-magic Nickel-48 in an
experimental at the SISSI/LISE3 facility of GANIL. Four Nickel-48 isotopes were
identified. In addition, roughly 100 Nickel-49, 50 Iron-45, and 290 Chromium-42
isotopes were observed. This opens the possibility to search for two-proton
emission from these nuclei.Comment: 4 pages, 3 figures, accepted for publication in Phys. Rev. Let
Identification of Residues in the Heme Domain of Soluble Guanylyl Cyclase that are Important for Basal and Stimulated Catalytic Activity
Nitric oxide signals through activation of soluble guanylyl cyclase (sGC), a heme-containing heterodimer. NO binds to the heme domain located in the N-terminal part of the β subunit of sGC resulting in increased production of cGMP in the catalytic domain located at the C-terminal part of sGC. Little is known about the mechanism by which the NO signaling is propagated from the receptor domain (heme domain) to the effector domain (catalytic domain), in particular events subsequent to the breakage of the bond between the heme iron and Histidine 105 (H105) of the β subunit. Our modeling of the heme-binding domain as well as previous homologous heme domain structures in different states point to two regions that could be critical for propagation of the NO activation signal. Structure-based mutational analysis of these regions revealed that residues T110 and R116 in the αF helix-β1 strand, and residues I41 and R40 in the αB-αC loop mediate propagation of activation between the heme domain and the catalytic domain. Biochemical analysis of these heme mutants allows refinement of the map of the residues that are critical for heme stability and propagation of the NO/YC-1 activation signal in sGC
(Micro)evolutionary changes and the evolutionary potential of bird migration
Seasonal migration is the yearly long-distance movement of individuals between their breeding and wintering grounds. Individuals from nearly every animal group exhibit this behavior, but probably the most iconic migration is carried out by birds, from the classic V-shape formation of geese on migration to the amazing nonstop long-distance flights undertaken by Arctic Terns Sterna paradisaea. In this chapter, we discuss how seasonal migration has shaped the field of evolution. First, this behavior is known to turn on and off quite rapidly, but controversy remains concerning where this behavior first evolved geographically and whether the ancestral state was sedentary or migratory (Fig. 7.1d, e). We review recent work using new analytical techniques to provide insight into this topic. Second, it is widely accepted that there is a large genetic basis to this trait, especially in groups like songbirds that migrate alone and at night precluding any opportunity for learning. Key hypotheses on this topic include shared genetic variation used by different populations to migrate and only few genes being involved in its control. We summarize recent work using new techniques for both phenotype and genotype characterization to evaluate and challenge these hypotheses. Finally, one topic that has received less attention is the role these differences in migratory phenotype could play in the process of speciation. Specifically, many populations breed next to one another but take drastically different routes on migration (Fig. 7.2). This difference could play an important role in reducing gene flow between populations, but our inability to track most birds on migration has so far precluded evaluations of this hypothesis. The advent of new tracking techniques means we can track many more birds with increasing accuracy on migration, and this work has provided important insight into migration's role in speciation that we will review here
Coping Skills Practice and Symptom Change: A Secondary Analysis of a Pilot Telephone Symptom Management Intervention for Lung Cancer Patients and their Family Caregivers
Context
Little research has explored coping skills practice in relation to symptom outcomes in psychosocial interventions for cancer patients and their family caregivers.
Objectives
To examine associations of coping skills practice to symptom change in a telephone symptom management (TSM) intervention delivered concurrently to lung cancer patients and their caregivers.
Methods
This study was a secondary analysis of a randomized pilot trial. Data were examined from patient-caregiver dyads (n=51 dyads) that were randomized to the TSM intervention. Guided by social cognitive theory, TSM involved four weekly sessions where dyads were taught coping skills including: a mindfulness exercise, guided imagery, pursed lips breathing, cognitive restructuring, problem solving, emotion-focused coping, and assertive communication. Symptoms were assessed, including patient and caregiver psychological distress and patient pain interference, fatigue interference, and distress related to breathlessness. Multiple regression analyses examined associations of coping skills practice during the intervention to symptoms at 6 weeks post-intervention.
Results
For patients, greater practice of assertive communication was associated with less pain interference (β=-0.45, p=0.02) and psychological distress (β=-0.36, p=0.047); for caregivers, greater practice of guided imagery was associated with less psychological distress (β=-0.30, p=0.01). Unexpectedly, for patients, greater practice of a mindfulness exercise was associated with higher pain (β=0.47, p=0.07) and fatigue interference (β=0.49, p=0.04); greater practice of problem solving was associated with higher distress related to breathlessness (β=0.56, p=0.01) and psychological distress (β=0.36, p=0.08).
Conclusion
Findings suggest the effectiveness of TSM may have been reduced by competing effects of certain coping skills. Future interventions should consider focusing on assertive communication training for patients and guided imagery for caregivers
Improving the performance of bright quantum dot single photon sources using amplitude modulation
Single epitaxially-grown semiconductor quantum dots have great potential as
single photon sources for photonic quantum technologies, though in practice
devices often exhibit non-ideal behavior. Here, we demonstrate that amplitude
modulation can improve the performance of quantum-dot-based sources. Starting
with a bright source consisting of a single quantum dot in a fiber-coupled
microdisk cavity, we use synchronized amplitude modulation to temporally filter
the emitted light. We observe that the single photon purity, temporal overlap
between successive emission events, and indistinguishability can be greatly
improved with this technique. As this method can be applied to any triggered
single photon source, independent of geometry and after device fabrication, it
is a flexible approach to improve the performance of solid-state systems, which
often suffer from excess dephasing and multi-photon background emission
Proton Drip-Line Calculations and the Rp-process
One-proton and two-proton separation energies are calculated for proton-rich
nuclei in the region . The method is based on Skyrme Hartree-Fock
calculations of Coulomb displacement energies of mirror nuclei in combination
with the experimental masses of the neutron-rich nuclei. The implications for
the proton drip line and the astrophysical rp-process are discussed. This is
done within the framework of a detailed analysis of the sensitivity of rp
process calculations in type I X-ray burst models on nuclear masses. We find
that the remaining mass uncertainties, in particular for some nuclei with
, still lead to large uncertainties in calculations of X-ray burst light
curves. Further experimental or theoretical improvements of nuclear mass data
are necessary before observed X-ray burst light curves can be used to obtain
quantitative constraints on ignition conditions and neutron star properties. We
identify a list of nuclei for which improved mass data would be most important.Comment: 20 pages, 9 figures, 2 table
Randomized Pilot Trial of a Telephone Symptom Management Intervention for Symptomatic Lung Cancer Patients and Their Family Caregivers
Context
Lung cancer is one of the most common cancers affecting both men and women and is associated with high symptom burden and psychological distress. Lung cancer patients’ family caregivers also show high rates of distress. However, few interventions have been tested to alleviate significant problems of this population.
Objectives
This study examined the preliminary efficacy of telephone-based symptom management (TSM) for symptomatic lung cancer patients and their family caregivers.
Methods
Symptomatic lung cancer patients and caregivers (N=106 dyads) were randomly assigned to 4 sessions of TSM consisting of cognitive-behavioral and emotion-focused therapy or an education/support condition. Patients completed measures of physical and psychological symptoms, self-efficacy for managing symptoms, and perceived social constraints from the caregiver; caregivers completed measures of psychological symptoms, self-efficacy for helping the patient manage symptoms and managing their own emotions, perceived social constraints from the patient, and caregiving burden.
Results
No significant group differences were found for all patient outcomes and caregiver self-efficacy for helping the patient manage symptoms and caregiving burden at 2 and 6-weeks post-intervention. Small effects in favor of TSM were found regarding caregiver self-efficacy for managing their own emotions and perceived social constraints from the patient. Study outcomes did not significantly change over time in either group.
Conclusion
Findings suggest that our brief telephone-based psychosocial intervention is not efficacious for symptomatic lung cancer patients and their family caregivers. Next steps include examining specific intervention components in relation to study outcomes, mechanisms of change, and differing intervention doses and modalities
NQO2 is a reactive oxygen species generating off-target for acetaminophen
[Image: see text] The analgesic and antipyretic compound acetaminophen (paracetamol) is one of the most used drugs worldwide. Acetaminophen overdose is also the most common cause for acute liver toxicity. Here we show that acetaminophen and many structurally related compounds bind quinone reductase 2 (NQO2) in vitro and in live cells, establishing NQO2 as a novel off-target. NQO2 modulates the levels of acetaminophen derived reactive oxygen species, more specifically superoxide anions, in cultured cells. In humans, NQO2 is highly expressed in liver and kidney, the main sites of acetaminophen toxicity. We suggest that NQO2 mediated superoxide production may function as a novel mechanism augmenting acetaminophen toxicity
Electromagnetically Induced Transparency and Slow Light with Optomechanics
Controlling the interaction between localized optical and mechanical
excitations has recently become possible following advances in micro- and
nano-fabrication techniques. To date, most experimental studies of
optomechanics have focused on measurement and control of the mechanical
subsystem through its interaction with optics, and have led to the experimental
demonstration of dynamical back-action cooling and optical rigidity of the
mechanical system. Conversely, the optical response of these systems is also
modified in the presence of mechanical interactions, leading to strong
nonlinear effects such as Electromagnetically Induced Transparency (EIT) and
parametric normal-mode splitting. In atomic systems, seminal experiments and
proposals to slow and stop the propagation of light, and their applicability to
modern optical networks, and future quantum networks, have thrust EIT to the
forefront of experimental study during the last two decades. In a similar
fashion, here we use the optomechanical nonlinearity to control the velocity of
light via engineered photon-phonon interactions. Our results demonstrate EIT
and tunable optical delays in a nanoscale optomechanical crystal device,
fabricated by simply etching holes into a thin film of silicon (Si). At low
temperature (8.7 K), we show an optically-tunable delay of 50 ns with
near-unity optical transparency, and superluminal light with a 1.4 microseconds
signal advance. These results, while indicating significant progress towards an
integrated quantum optomechanical memory, are also relevant to classical signal
processing applications. Measurements at room temperature and in the analogous
regime of Electromagnetically Induced Absorption (EIA) show the utility of
these chip-scale optomechanical systems for optical buffering, amplification,
and filtering of microwave-over-optical signals.Comment: 15 pages, 9 figure
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