533 research outputs found
The Enantioselective Construction of Tetracyclic Diterpene Skeletons with Friedel-Crafts Alkylation and Palladium-catalyzed Cycloalkenylation Reactions
Due to the profound extent to which natural products inspire medicinal chemists in drug discovery, there is demand for innovative syntheses of these often complex materials. This article describes the synthesis of tricarbocyclic natural product architectures through an extension of the enantioselective Birch-Cope sequence with intramolecular Friedel-Crafts alkylation reactions. Additionally, palladium-catalyzed enol silane cycloalkenylation of the tricarbocyclic structures afforded the challenging bicyclo[3.2.1]octane C/D ring system found in the gibberellins and the ent-kauranes, two natural products with diverse medicinal value. In the case of the ent-kaurane derivative, an unprecedented alkene rearrangement converted four alkene isomers to one final product
Comparing Moral Reasoning across Graduate Occupational and Physical Therapy Students and Practitioners
Practicing clinicians must use moral reasoning to solve ethical problems and combat moral distress. Development of moral reasoning in occupational therapy (OT) and physical therapy (PT) students has been significantly under researched. The purpose of this study was to analyze the differences in moral reasoning between first year and second year OT and PT students and between students and OT and PT practitioners. Investigators utilized a cross-sectional study design with a convenience sample of University of Indianapolis OT and PT students and a combination of convenience and snowball sampling to recruit licensed OT and PT practitioners. One hundred and fifty-four participants completed the Defining Issues Test - 2 (DIT-2; Rest et al., 1999) survey. Comparisons of N2 scores using t-tests found no differences between groups in moral reasoning schema (one’s preferred way of approaching moral issues, divided into stratified developmental levels). However, Pearson’s Chi-Square analysis for a comparison of all students to all practitioners for moral reasoning patterns (one’s ability to discriminate between types of moral reasoning schemas when presented with a complex moral dilemma) was significant between students (transitional) and practitioners (consolidated), with the greatest difference between second-year students and practitioners. Continual expansion of ethics content, including interjecting clinical experiences into the classroom, within OT and PT graduate programs may promote moral reasoning pattern development with carryover into practice. Clinical experiences provide real-world opportunities necessary to progress students from transitional to consolidated thinking patterns. To improve ethics education, authors recommend active learning strategies and ethics mentorship throughout clinical experiences
Adult Environmental Education and the Cultural Commons: A Study of Community Practices for a Just and Sustainable World
Ecojustice adult education, an extension of adult environmental education, has been spurred on by international efforts to educate adults about environmental issues. It is a new and evolving arm of the adult education field that studies the ways that dominant views are impacting human/earth relationships. Ecojustice education teaches about the natural and cultural commons that sustain all life. In this symposiusm, doctoral students investigated their own communities to find examples of the cultural commons
An unidentified Fermi source emitting radio bursts in the Galactic bulge
We report on the detection of radio bursts from the Galactic bulge using the
real-time transient detection and localization system, realfast. The pulses
were detected commensally on the Karl G. Jansky Very Large Array during a
survey of unidentified Fermi -ray sources. The bursts were localized to
subarcsecond precision using realfast fast-sampled imaging. Follow-up
observations with the Green Bank Telescope detected additional bursts from the
same source. The bursts do not exhibit periodicity in a search up to periods of
480s, assuming a duty cycle of < 20%. The pulses are nearly 100% linearly
polarized, show circular polarization up to 12%, have a steep radio spectral
index of -2.7, and exhibit variable scattering on timescales of months. The
arcsecond-level realfast localization links the source confidently with the
Fermi -ray source and places it nearby (though not coincident with) an
XMM-Newton X-ray source. Based on the source's overall properties, we discuss
various options for the nature of this object and propose that it could be a
young pulsar, magnetar, or a binary pulsar system.Comment: Submitted to The Astrophysical Journa
Assessing behavioural changes in ALS: cross-validation of ALS-specific measures
Objective: The Beaumont Behavioural Inventory (BBI) is a behavioural proxy report for the assessment of behavioural changes in ALS. This tool has been validated against the FrSBe, a non-ALS specific behavioural assessment, and further comparison of the BBI against a disease-specific tool was considered. This study cross-validates the BBI against the ALS-FTD-Q.
Methods: 60 ALS patients, 8% also meeting criteria for FTD, were recruited. All patients were evaluated using the BBI and the ALS-FTD-Q, completed by a carer. Correlational analysis was performed to assess construct validity. Precision, sensitivity, specificity and overall accuracy of the BBI, when compared to the ALS-FTD-Q, were obtained.
Results: The mean score of the whole sample on the BBI was 11.45±13.06. ALS-FTD patients scored significantly higher than non-demented ALS patients (31.6±14.64, 9.62±11.38; p<.0001). A significant large positive correlation between the BBI and the ALS-FTD-Q was observed (r=.807, p<.0001), and no significant correlations between the BBI and other clinical/demographic characteristics, indicating good convergent and discriminant validity, respectively. 72% of overall concordance was observed. Precision, sensitivity and specificity for the classification of severely impaired patients were adequate. However, lower concordance in the classification of mild behavioural changes was observed, with higher sensitivity using the BBI, most likely secondary to BBI items which endorsed behavioural aspects not measured by the ALS-FTD-Q.
Discussion: Good construct validity has been further confirmed when the BBI is compared to an ALS-specific tool. Furthermore, the BBI is a more comprehensive behavioural assessment for ALS, as it measures the whole behavioural spectrum in this condition
Innovative package for frontline maternal, newborn and child health workers in South Sudan
Improving maternal, newborn, and child health is a leading priority worldwide. It is a particularly urgent issue in South Sudan, which suffers from the world’s worst maternal mortality and among the worst newborn and child mortalities. A leading barrier to improving these health indices is limited frontline health worker capacity. In partnership with the Ministry of Health, the Division of Global Health and Human Rights (Department of Emergency Medicine, Massachusetts General Hospital, Boston, USA) has developed and is currently implementing its novel Maternal, Newborn, and Child Survival (MNCS) Initiative throughout much of South Sudan. The purpose of MNCS is to build frontline health worker capacity through a training package that includes:1. A participatory training course2. Pictorial checklists to guide prevention, care, and referral3. Re-useable medical equipment and commodities.Program implementation began in November 2010 utilizing a training-of-trainers model. To date, 72 local trainers and 632 frontline health workers have completed the training and received their MNCS checklists and commodities. Initial monitoring and evaluation results are encouraging as further evaluation continues. This innovative training package may also serve as a model for building capacity for maternal, newborn, and child health in other resource limited settings beyond South Sudan
The Host Galaxy and Redshift of the Repeating Fast Radio Burst FRB 121102
The precise localization of the repeating fast radio burst (FRB 121102) has
provided the first unambiguous association (chance coincidence probability
) of an FRB with an optical and persistent radio
counterpart. We report on optical imaging and spectroscopy of the counterpart
and find that it is an extended ()
object displaying prominent Balmer and [OIII] emission lines. Based on the
spectrum and emission line ratios, we classify the counterpart as a
low-metallicity, star-forming, AB mag dwarf galaxy at a
redshift of , corresponding to a luminosity distance of 972 Mpc.
From the angular size, the redshift, and luminosity, we estimate the host
galaxy to have a diameter kpc and a stellar mass of
, assuming a mass-to-light ratio between 2 to
3. Based on the H flux, we estimate the star
formation rate of the host to be and a
substantial host dispersion measure depth .
The net dispersion measure contribution of the host galaxy to FRB 121102 is
likely to be lower than this value depending on geometrical factors. We show
that the persistent radio source at FRB 121102's location reported by Marcote
et al (2017) is offset from the galaxy's center of light by 200 mas and
the host galaxy does not show optical signatures for AGN activity. If FRB
121102 is typical of the wider FRB population and if future interferometric
localizations preferentially find them in dwarf galaxies with low metallicities
and prominent emission lines, they would share such a preference with long
gamma ray bursts and superluminous supernovae.Comment: 12 pages, 3 figures, Published in ApJ Letters. V2: Corrected mistake
in author lis
Multi-Messenger Gravitational Wave Searches with Pulsar Timing Arrays: Application to 3C66B Using the NANOGrav 11-year Data Set
When galaxies merge, the supermassive black holes in their centers may form
binaries and, during the process of merger, emit low-frequency gravitational
radiation in the process. In this paper we consider the galaxy 3C66B, which was
used as the target of the first multi-messenger search for gravitational waves.
Due to the observed periodicities present in the photometric and astrometric
data of the source of the source, it has been theorized to contain a
supermassive black hole binary. Its apparent 1.05-year orbital period would
place the gravitational wave emission directly in the pulsar timing band. Since
the first pulsar timing array study of 3C66B, revised models of the source have
been published, and timing array sensitivities and techniques have improved
dramatically. With these advances, we further constrain the chirp mass of the
potential supermassive black hole binary in 3C66B to less than using data from the NANOGrav 11-year data set. This
upper limit provides a factor of 1.6 improvement over previous limits, and a
factor of 4.3 over the first search done. Nevertheless, the most recent orbital
model for the source is still consistent with our limit from pulsar timing
array data. In addition, we are able to quantify the improvement made by the
inclusion of source properties gleaned from electromagnetic data to `blind'
pulsar timing array searches. With these methods, it is apparent that it is not
necessary to obtain exact a priori knowledge of the period of a binary to gain
meaningful astrophysical inferences.Comment: 14 pages, 6 figures. Accepted by Ap
Data Descriptor : Long-term chloride concentrations in North American and European freshwater lakes
Anthropogenic sources of chloride in a lake catchment, including road salt, fertilizer, and wastewater, can elevate the chloride concentration in freshwater lakes above background levels. Rising chloride concentrations can impact lake ecology and ecosystem services such as fisheries and the use of lakes as drinking water sources. To analyze the spatial extent and magnitude of increasing chloride concentrations in freshwater lakes, we amassed a database of 529 lakes in Europe and North America that had greater than or equal to ten years of chloride data. For each lake, we calculated climate statistics of mean annual total precipitation and mean monthly air temperatures from gridded global datasets. We also quantified land cover metrics, including road density and impervious surface, in buffer zones of 100 to 1,500m surrounding the perimeter of each lake. This database represents the largest global collection of lake chloride data. We hope that long-term water quality measurements in areas outside Europe and North America can be added to the database as they become available in the future.Peer reviewe
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