4,943 research outputs found
Complexity of a knot invariant
The algebraic structures called quandles constitute a complete invariant for tame knots. However, determining when two quandles are isomorphic is an empirically hard problem, so there is some dissatisfaction with quandles as knot invariants. We have confirmed this apparent difficulty, showing within the framework of Borel reducibility that the general isomorphism problem for quandles is as complex as possible
Probing the embedded YSOs of the R CrA region through VLT-ISAAC spectroscopy
Near IR spectra obtained with ISAAC at VLT, have been used to pose
constraints on the evolutionary state and accretion properties of a sample of
five embedded YSOs located in the R CrA core. This sample includes three Class
I sources (HH100 IR, IRS2 and IRS5), and two sources with NIR excesses (IRS6
and IRS3). Absorption lines have been detected in the medium resolution spectra
of all the observed targets, together with emission lines likely originating in
the disk-star-wind connected regions. We derived spectral types, veiling and
stellar luminosity of the five observed sources, which in turn have been used
to infer their mass and age adopting pre-main sequence evolutionary tracks. We
find that in HH100 IR and IRS2 most of the bolometric luminosity is due to
accretion, while the other three investigated sources, including the Class I
object IRS5a, present a low accretion activity (L_{acc}/L_{bol} < 0.2). We
observe a general correlation between the accretion luminosity, the IR veiling
and the emission line activity of the sources. A correlation between the
accretion activity and the spectral energy distribution slope is recognizable
but with the notable exception of IRS5a. Our analysis therefore shows how the
definition of the evolutionary stage of deeply embedded YSOs by means of IR
colors needs to be more carefully refined.Comment: 17 pages, 13 figures, accepted on A&
Remotely Sensed Canopy Nitrogen Correlates With Nitrous Oxide Emissions in a Lowland Tropical Rainforest
Tropical forests exhibit significant heterogeneity in plant functional and chemical traits that may contribute to spatial patterns of key soil biogeochemical processes, such as carbon storage and greenhouse gas emissions. Although tropical forests are the largest ecosystem source of nitrous oxide (N2O), drivers of spatial patterns within forests are poorly resolved. Here, we show that local variation in canopy foliar N, mapped by remoteâsensing image spectroscopy, correlates with patterns of soil N2O emission from a lowland tropical rainforest. We identified ten 0.25 ha plots (assemblages of 40â70 individual trees) in which average remotelyâsensed canopy N fell above or below the regional mean. The plots were located on a single minimallyâdissected terrace (km2) where soil type, vegetation structure and climatic conditions were relatively constant. We measured N2O fluxes monthly for 1 yr and found that high canopy N species assemblages had on average threeâfold higher total mean N2O fluxes than nearby lower canopy N areas. These differences are consistent with strong differences in litter stoichiometry, nitrification rates and soil nitrate concentrations. Canopy N status was also associated with microbial community characteristics: lower canopy N plots had twoâfold greater soil fungal to bacterial ratios and a significantly lower abundance of ammoniaâoxidizing archaea, although genes associated with denitrification (nirS, nirK, nosZ) showed no relationship with N2O flux. Overall, landscape emissions from this ecosystem are at the lowest end of the spectrum reported for tropical forests, consist with multiple metrics indicating that these highly productive forests retain N tightly and have low plantâavailable losses. These data point to connections between canopy and soil processes that have largely been overlooked as a driver of denitrification. Defining relationships between remotelyâsensed plant traits and soil processes offers the chance to map these processes at large scales, potentially increasing our ability to predict N2O emissions in heterogeneous landscapes
Communicating with providers about racial healthcare disparities: The role of providersâ prior beliefs on their receptivity to different narrative frames
Objective
Evaluate narratives aimed at motivating providers with different pre-existing beliefs to address racial healthcare disparities.
Methods
Survey experiment with 280 providers. Providers were classified as high or low in attributing disparities to providers (HPA versus LPA) and were randomly assigned to a non-narrative control or 1 of 2 narratives: âProvider Successâ (provider successfully resolved problem involving Black patient) and âProvider Biasâ (Black patient experienced racial bias, which remained unresolved). Participants' reactions to narratives (including identification with narrative) and likelihood of participating in disparities-reduction activities were immediately assessed. Four weeks later, participation in those activities was assessed, including self-reported participation in a disparities-reduction training course (primary outcome).
Results
Participation in training was higher among providers randomized to the Provider Success narrative compared to Provider Bias or Control. LPA participants had higher identification with Provider Success than Provider Bias narratives, whereas among HPA participants, differences in identification between the narratives were not significant.
Conclusions
Provider Success narratives led to greater participation in training than Provider Bias narratives, although providersâ pre-existing beliefs influenced the narrative they identified with.
Practice implications
Provider Success narratives may be more effective at motivating providers to address disparities than Provider Bias narratives, though more research is needed
Key features of palliative care service delivery to Indigenous peoples in Australia, New Zealand, Canada and the United States: A comprehensive review
Background: Indigenous peoples in developed countries have reduced life expectancies, particularly from chronic diseases. The lack of access to and take up of palliative care services of Indigenous peoples is an ongoing concern.
Objectives: To examine and learn from published studies on provision of culturally safe palliative care service delivery to Indigenous people in Australia, New Zealand (NZ), Canada and the United States of America (USA); and to compare Indigenous peoplesâ preferences, needs, opportunities and barriers to palliative care.
Methods: A comprehensive search of multiple databases was undertaken. Articles were included if they were published in English from 2000 onwards and related to palliative care service delivery for Indigenous populations; papers could use quantitative or qualitative approaches. Common themes were identified using thematic synthesis. Studies were evaluated using Dalyâs hierarchy of evidence-for-practice in qualitative research.
Results: Of 522 articles screened, 39 were eligible for inclusion. Despite diversity in Indigenous peoplesâ experiences across countries, some commonalities were noted in the preferences for palliative care of Indigenous people: to die close to or at home; involvement of family; and the integration of cultural practices. Barriers identified included inaccessibility, affordability, lack of awareness of services, perceptions of palliative care, and inappropriate services. Identified models attempted to address these gaps by adopting the following strategies: community engagement and ownership; flexibility in approach; continuing education and training; a whole-of-service approach; and local partnerships among multiple agencies. Better engagement with Indigenous clients, an increase in number of palliative care patients, improved outcomes, and understanding about palliative care by patients and their families were identified as positive achievements.
Conclusions: The results provide a comprehensive overview of identified effective practices with regards to palliative care delivered to Indigenous populations to guide future program developments in this field. Further research is required to explore the palliative care needs and experiences of Indigenous people living in urban areas
Does adherence to falls prevention exercise programmes benefit bone mineral density in older people? The ProAct65+ bone study [abstract]
Does adherence to falls prevention exercise programmes benefit bone mineral density in older people? The ProAct65+ bone study [abstract
Supporting the consumption and co-authoring of locative media experiences for a rural village community: design and field trial evaluation of the SHARC2.0 framework
Locative Media Experiences (LMEs) have significant potential in enabling visitors to engage with the places that they visit through an appreciation of local history. For example, a visitor to Berlin that is exploring remnants of the Berlin Wall may be encouraged to appreciate (or in part experience) the falling of the Berlin wall by consuming multimedia directly related to her current location such as listening to audio recordings of the assembled crowds on 10th November 1989. However, despite the growing popularity of enabling technologies (such as GPS-equipped smart phones and tablets), the availability of tools that support the authoring of LMEs is limited. In addition, mobile apps that support the consumption of LMEs typically adopt an approach that precludes users from being able to respond with their own multimedia contributions. In this article we describe the design and evaluation of the SHARC2.0 framework that has been developed as part of our long-term and participatory engagement with the rural village of Wray in the north of England. Wray has very limited cellular data coverage which has placed a requirement on the framework and associated tools to operate without reliance on network connectivity. A field study is presented which featured a LME relating to Wrayâs local history and which contained multimedia content contributed by members of the community including historic photos (taken from an existing âDigital Noticeboardâ system), audio-clips (from a local historian and village residents) and video (contributed during a design workshop). The novelty of our approach relates to the ability of multiple authors to contribute to a LME in-situ, and the utilisation of personal cloud storage for storing the contents associated with a multi-authored LME
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Development of Abraham model correlations for solvation characteristics of linear alcohols
This article discusses the development of Abraham model correlations for solvation characteristics of linear alcohols
CichoĆâs diagram for uncountable cardinals
We develop a version of CichoĆâs diagram for cardinal invariants on the generalized Cantor space 2 Îș or the generalized Baire space Îș Îș , where Îș is an uncountable regular cardinal. For strongly inaccessible Îș, many of the ZFC-results about the order relationship of the cardinal invariants which hold for Ï generalize; for example, we obtain a natural generalization of the BartoszyĆskiâRaisonnierâStern Theorem. We also prove a number of independence results, both with < Îș-support iterations and Îș-support iterations and products, showing that we consistently have strict inequality between some of the cardinal invariants
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