114 research outputs found
Reproducibility of Serologic Assays for Influenza Virus A (H5N1)
Results for clade 1 viruses were more consistent among laboratories when a standard antibody was used
A Planetary Companion to gamma Cephei A
We report on the detection of a planetary companion in orbit around the
primary star of the binary system Cephei. High precision radial
velocity measurements using 4 independent data sets spanning the time interval
1981--2002 reveal long-lived residual radial velocity variations superimposed
on the binary orbit that are coherent in phase and amplitude with a period or
2.48 years (906 days) and a semi-amplitude of 27.5 m s. We performed a
careful analysis of our Ca II H & K S-index measurements, spectral line
bisectors, and {\it Hipparcos} photometry. We found no significant variations
in these quantities with the 906-d period. We also re-analyzed the Ca II
8662 {\AA} measurements of Walker et al. (1992) which showed possible
periodic variations with the ``planet'' period when first published. This
analysis shows that periodic Ca II equivalent width variations were only
present during 1986.5 -- 1992 and absent during 1981--1986.5. Furthermore, a
refined period for the Ca II 8662 {\AA} variations is 2.14 yrs,
significantly less than residual radial velocity period. The most likely
explanation of the residual radial velocity variations is a planetary mass
companion with sin = 1.7 and an orbital semi-major axis
of 2.13 AU. This supports the planet hypothesis for the residual
radial velocity variations for Cep first suggested by Walker et al.
(1992). With an estimated binary orbital period of 57 years Cep is the
shortest period binary system in which an extrasolar planet has been found.
This system may provide insights into the relationship between planetary and
binary star formation.Comment: 19 pages, 15 figures, accepted in Ap. J. Includes additional data and
improved orbital solutio
Implementation of EAPs
This Research Note describes how to effectively implement employee assistance program services in an organization
The Extrasolar Planet epsilon Eridani b - Orbit and Mass
Hubble Space Telescope observations of the nearby (3.22 pc), K2 V star
epsilon Eridani have been combined with ground-based astrometric and radial
velocity data to determine the mass of its known companion. We model the
astrometric and radial velocity measurements simultaneously to obtain the
parallax, proper motion, perturbation period, perturbation inclination, and
perturbation size. Because of the long period of the companion, \eps b, we
extend our astrometric coverage to a total of 14.94 years (including the three
year span of the \HST data) by including lower-precision ground-based
astrometry from the Allegheny Multichannel Astrometric Photometer. Radial
velocities now span 1980.8 -- 2006.3. We obtain a perturbation period, P = 6.85
+/- 0.03 yr, semi-major axis, alpha =1.88 +/- 0.20 mas, and inclination i =
30.1 +/- 3.8 degrees. This inclination is consistent with a previously measured
dust disk inclination, suggesting coplanarity. Assuming a primary mass M_* =
0.83 M_{\sun}, we obtain a companion mass M = 1.55 +/- 0.24 M_{Jup}. Given the
relatively young age of epsilon Eri (~800 Myr), this accurate exoplanet mass
and orbit can usefully inform future direct imaging attempts. We predict the
next periastron at 2007.3 with a total separation, rho = 0.3 arcsec at position
angle, p.a. = -27 degrees. Orbit orientation and geometry dictate that epsilon
Eri b will appear brightest in reflected light very nearly at periastron.
Radial velocities spanning over 25 years indicate an acceleration consistent
with a Jupiter-mass object with a period in excess of 50 years, possibly
responsible for one feature of the dust morphology, the inner cavity
How fast is fast enough? Academic behavioural science impacting public health policy and practice
Background: COVID-19 emphasised the crucial role behaviour change plays in protecting population health. However, the interchange between academic behavioural science and Public Health (PH) policy and practice could be strengthened. We aimed to establish a sustainable method of joint working between two groups in North Scotland to enable rapid impact of behavioural science on population health.Methods: An implementation-sciences based approach tested the initial 4 steps of an 8-step collaboration process model, designed to identify a health problem (step 1), develop and test messaging interventions (step 2-4), implement the intervention (steps 5-6), and evaluate impact (steps 7-8).Results: Since October 2022, fortnightly meetings were established, implementing the process model. This project will focus on the following outcomes: perceived collaboration usefulness, collaboration-process barriers, and facilitators.Conclusions: Unless a sustainable method of joint working can be established in times where there are no urgent PH priorities, it is unlikely that the fruits of behavioural science can be aligned with PH challenges when outbreaks are happening to rapidly impact population health.<br/
How fast is fast enough? Academic behavioural science impacting public health policy and practice
Background: COVID-19 emphasised the crucial role behaviour change plays in protecting population health. However, the interchange between academic behavioural science and Public Health (PH) policy and practice could be strengthened. We aimed to establish a sustainable method of joint working between two groups in North Scotland to enable rapid impact of behavioural science on population health.Methods: An implementation-sciences based approach tested the initial 4 steps of an 8-step collaboration process model, designed to identify a health problem (step 1), develop and test messaging interventions (step 2-4), implement the intervention (steps 5-6), and evaluate impact (steps 7-8).Results: Since October 2022, fortnightly meetings were established, implementing the process model. This project will focus on the following outcomes: perceived collaboration usefulness, collaboration-process barriers, and facilitators.Conclusions: Unless a sustainable method of joint working can be established in times where there are no urgent PH priorities, it is unlikely that the fruits of behavioural science can be aligned with PH challenges when outbreaks are happening to rapidly impact population health.<br/
Histopathologic characterization of the BTBR mouse model of autistic-like behavior reveals selective changes in neurodevelopmental proteins and adult hippocampal neurogenesis
<p>Abstract</p> <p>Background</p> <p>The inbred mouse strain BTBR T+ tf/J (BTBR) exhibits behavioral deficits that mimic the core deficits of autism. Neuroanatomically, the BTBR strain is also characterized by a complete absence of the corpus callosum. The goal of this study was to identify novel molecular and cellular changes in the BTBR mouse, focusing on neuronal, synaptic, glial and plasticity markers in the limbic system as a model for identifying putative molecular and cellular substrates associated with autistic behaviors.</p> <p>Methods</p> <p>Forebrains of 8 to 10-week-old male BTBR and age-matched C57Bl/6J control mice were evaluated by immunohistochemistry using free-floating and paraffin embedded sections. Twenty antibodies directed against antigens specific to neurons, synapses and glia were used. Nissl, Timm and acetylcholinesterase (AchE) stains were performed to assess cytoarchitecture, mossy fibers and cholinergic fiber density, respectively. In the hippocampus, quantitative stereological estimates for the mitotic marker bromodeoxyuridine (BrdU) were performed to determine hippocampal progenitor proliferation, survival and differentiation, and brain-derived neurotrophic factor (BDNF) mRNA was quantified by <it>in situ </it>hybridization. Quantitative image analysis was performed for NG2, doublecortin (DCX), NeuroD, GAD67 and Poly-Sialic Acid Neural Cell Adhesion Molecule (PSA-NCAM).</p> <p>Results</p> <p>In midline structures including the region of the absent corpus callosum of BTBR mice, the myelin markers 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) and myelin basic protein (MBP) were reduced, and the oligodendrocyte precursor NG2 was increased. MBP and CNPase were expressed in small ectopic white matter bundles within the cingulate cortex. Microglia and astrocytes showed no evidence of gliosis, yet orientations of glial fibers were altered in specific white-matter areas. In the hippocampus, evidence of reduced neurogenesis included significant reductions in the number of doublecortin, PSA-NCAM and NeuroD immunoreactive cells in the subgranular zone of the dentate gyrus, and a marked reduction in the number of 5-bromo-2'-deoxyuridine (BrdU) positive progenitors. Furthermore, a significant and profound reduction in BDNF mRNA was seen in the BTBR dentate gyrus. No significant differences were seen in the expression of AchE, mossy fiber synapses or immunoreactivities of microtubule-associated protein MAP2, parvalbumin and glutamate decarboxylase GAD65 or GAD67 isoforms.</p> <p>Conclusions</p> <p>We documented modest and selective alterations in glia, neurons and synapses in BTBR forebrain, along with reduced neurogenesis in the adult hippocampus. Of all markers examined, the most distinctive changes were seen in the neurodevelopmental proteins NG2, PSA-NCAM, NeuroD and DCX. Our results are consistent with aberrant development of the nervous system in BTBR mice, and may reveal novel substrates to link callosal abnormalities and autistic behaviors. The changes that we observed in the BTBR mice suggest potential novel therapeutic strategies for intervention in autism spectrum disorders.</p
Metadata Framework to Support Deployment of Digital Health Technologies in Clinical Trials in Parkinson’s Disease
Sensor data from digital health technologies (DHTs) used in clinical trials provides a valuable source of information, because of the possibility to combine datasets from different studies, to combine it with other data types, and to reuse it multiple times for various purposes. To date, there exist no standards for capturing or storing DHT biosensor data applicable across modalities and disease areas, and which can also capture the clinical trial and environment-specific aspects, so-called metadata. In this perspectives paper, we propose a metadata framework that divides the DHT metadata into metadata that is independent of the therapeutic area or clinical trial design (concept of interest and context of use), and metadata that is dependent on these factors. We demonstrate how this framework can be applied to data collected with different types of DHTs deployed in the WATCH-PD clinical study of Parkinson’s disease. This framework provides a means to pre-specify and therefore standardize aspects of the use of DHTs, promoting comparability of DHTs across future studies
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