885 research outputs found
Cold gas and a Milky Way-type 2175 {\AA} bump in a metal-rich and highly depleted absorption system
We report the detection of a strong Milky Way-type 2175 \AA extinction
bump at = 2.1166 in the quasar spectrum towards SDSS J121143.42+083349.7
from the Sloan Digital Sky Survey (SDSS) Data Release 10. We conduct follow up
observations with the Echelle Spectrograph and Imager (ESI) onboard the Keck-II
telescope and the Ultraviolet and Visual Echelle Spectrograph (UVES) on the
VLT. This 2175 \AA absorber is remarkable in that we simultaneously detect
neutral carbon (C I), neutral chlorine (Cl I), and carbon monoxide (CO). It
also qualifies as a damped Lyman alpha system. The J1211+0833 absorber is found
to be metal-rich and has a dust depletion pattern resembling that of the Milky
Way disk clouds. We use the column densities of the C I fine structure states
and the C II/C I ratio (under the assumption of ionization equilibrium) to
derive the temperature and volume density in the absorbing gas. A Cloudy
photoionization model is constructed, which utilizes additional atoms/ions to
constrain the physical conditions. The inferred physical conditions are
consistent with a canonical cold (T 100 K) neutral medium with a high
density ((H I) 100 cm) and a slightly higher pressure than the
local interstellar medium. Given the simultaneous presence of C I, CO, and the
2175 \AA bump, combined with the high metallicity, high dust depletion level
and overall low ionization state of the gas, the absorber towards J1211+0833
supports the scenario that the presence of the bump requires an evolved stellar
population.Comment: 18 pages, 17 figures, to be published in MNRA
Consumer perspectives on the use of Artificial Intelligence technology and automation in crisis support services: Mixed methods study
BACKGROUND: Emerging technologies, such as artificial intelligence (AI), have the potential to enhance service responsiveness and quality, improve reach to underserved groups, and help address the lack of workforce capacity in health and mental health care. However, little research has been conducted on the acceptability of AI, particularly in mental health and crisis support, and how this may inform the development of responsible and responsive innovation in the area. OBJECTIVE: This study aims to explore the level of support for the use of technology and automation, such as AI, in Lifeline’s crisis support services in Australia; the likelihood of service use if technology and automation were implemented; the impact of demographic characteristics on the level of support and likelihood of service use; and reasons for not using Lifeline’s crisis support services if technology and automation were implemented in the future. METHODS: A mixed methods study involving a computer-assisted telephone interview and a web-based survey was undertaken from 2019 to 2020 to explore expectations and anticipated outcomes of Lifeline’s crisis support services in a nationally representative community sample (n=1300) and a Lifeline help-seeker sample (n=553). Participants were aged between 18 and 93 years. Quantitative descriptive analysis, binary logistic regression models, and qualitative thematic analysis were conducted to address the research objectives. RESULTS: One-third of the community and help-seeker participants did not support the collection of information about service users through technology and automation (ie, via AI), and approximately half of the participants reported that they would be less likely to use the service if automation was introduced. Significant demographic differences were observed between the community and help-seeker samples. Of the demographics, only older age predicted being less likely to endorse technology and automation to tailor Lifeline’s crisis support service and use such services (odds ratio 1.48-1.66, 99% CI 1.03-2.38; P<.001 to P=.005). The most common reason for reluctance, reported by both samples, was that respondents wanted to speak to a real person, assuming that human counselors would be replaced by automated robots or machine services. CONCLUSIONS: Although Lifeline plans to always have a real person providing crisis support, help-seekers automatically fear this will not be the case if new technology and automation such as AI are introduced. Consequently, incorporating innovative use of technology to improve help-seeker outcomes in such services will require careful messaging and assurance that the human connection will continue
Machine Learning for Holistic Evaluation of Scientific Essays
Abstract. In the US in particular, there is an increasing emphasis on the importance of science in education. To better understand a scien-tific topic, students need to compile information from multiple sources and determine the principal causal factors involved. We describe an ap-proach for automatically inferring the quality and completeness of causal reasoning in essays on two separate scientific topics using a novel, two-phase machine learning approach for detecting causal relations. For each core essay concept, we initially trained a window-based tagging model to predict which individual words belonged to that concept. Using the predictions from this first set of models, we then trained a second stacked model on all the predicted word tags present in a sentence to predict in-ferences between essay concepts. The results indicate we could use such a system to provide explicit feedback to students to improve reasoning and essay writing skills
Recruitment regime shifts and nonstationarity are widespread phenomena in harvestable stocks experiencing pronounced climate fluctuations
Methods to reliably identify jump discontinuities in biological time series and to assess the specific contribution of various covariates are rapidly progressing. Here, we took advantage of these statistical improvements as well as those seen in complementary, down-scaled climate and biogeochemical models to investigate causes of the substantial interannual variability observed in recruitment strength in hindcast analyses. This systematic meta-analysis included 23 data-rich, commercially valuable, warm- and cold-temperate stocks in the North, Norwegian and Barents Seas. Since this study focuses on recruitment strength variability, we have used the term “recruitment regime shift” to distinguish from the concept of ecosystem regime shift. The breakpoint analysis revealed that the former criterion applied to more than half of the time series, mainly with respect to North Sea stocks but also to those in the Norwegian Sea. The exploratory analysis using vcGAM indicated that 1–3 shifts per stock were real, when using five drivers spanning spawning stock biomass to large-scale climatic processes. Thus, non-stationary relationships were extensively prevalent, indicating that each stock is uniquely adapted to its locally varying conditions. Outputs from the stationary GAM resembled those from the vcGAM but not after the threshold year. In-depth case studies showed that the proxy of a given driver for the process which was to be included should be critically considered in a spatiotemporal context. Furthermore, the stock-specific uncertainty associated with the given recruitment figures as such should also be an in-built component of the model construct and thereby in the evaluation of the output.Recruitment regime shifts and nonstationarity are widespread phenomena in harvestable stocks experiencing pronounced climate fluctuationspublishedVersio
Fulminant hyperpyrexia induced by bleomycin
Mild and self-limiting fever following bleomycin use is common, and a fatal hyperpyrexial response occurs rarely. In previously reported cases, such hyperpyrexia occurred either after the initial administration of the drug or during subsequent therapy following an initial pyrexial response. We describe a fatal hyperpyrexial reaction after bleomycin in a patient with T-cell lymphoma who had had no febrile response when she received her initial injection 3 weeks earlier. Since the occurrence of this hyperpyrexial response is unpredictable, health care workers as well as patients and relatives should always be alert to this potentially lethal complication and prompt measures should be taken in any patient who develops fever after bleomycin use.published_or_final_versio
A randomised controlled trial and cost-effectiveness evaluation of "booster" interventions to sustain increases in physical activity in middle-aged adults in deprived urban neighbourhoods
Background: Systematic reviews have identified a range of brief interventions which increase physical activity in previously sedentary people. There is an absence of evidence about whether follow up beyond three months can maintain long term physical activity. This study assesses whether it is worth providing motivational interviews, three months after giving initial advice, to those who have become more active.
Methods/Design: Study candidates (n = 1500) will initially be given an interactive DVD and receive two telephone follow ups at monthly intervals checking on receipt and use of the DVD. Only those that have increased their physical activity after three months (n = 600) will be randomised into the study. These participants will receive either a "mini booster" (n = 200), "full booster" (n = 200) or no booster (n = 200). The "mini booster" consists of two telephone calls one month apart to discuss physical activity and maintenance strategies. The "full booster" consists of a face-to-face meeting with the facilitator at the same intervals. The purpose of these booster sessions is to help the individual maintain their increase in physical activity. Differences in physical activity, quality of life and costs associated with the booster interventions, will be measured three and nine months from randomisation. The research will be conducted in 20 of the most deprived neighbourhoods in Sheffield, which have large, ethnically diverse populations, high levels of economic deprivation, low levels of physical activity, poorer health and shorter life expectancy. Participants will be recruited through general practices and community groups, as well as by postal invitation, to ensure the participation of minority ethnic groups and those with lower levels of literacy. Sheffield City Council and Primary Care Trust fund a range of facilities and activities to promote physical activity and variations in access to these between neighbourhoods will make it possible to examine whether the effectiveness of the intervention is modified by access to community facilities. A one-year integrated feasibility study will confirm that recruitment targets are achievable based on a 10% sample.Discussion: The choice of study population, study interventions, brief intervention preceding the study, and outcome measure are discussed
Galaxy clustering in the NEWFIRM Medium Band Survey: the relationship between stellar mass and dark matter halo mass at 1 < z < 2
We present an analysis of the clustering of galaxies as a function of their
stellar mass at 1 < z < 2 using data from the NEWFIRM Medium Band Survey
(NMBS). The precise photometric redshifts and stellar masses that the NMBS
produces allows us to define a series of mass limited samples of galaxies more
massive than 0.7, 1 and 3x10^10 Msun in redshift intervals centered on z = 1.1,
1.5 and 1.9 respectively. In each redshift interval we show that there exists a
strong dependence of clustering strength on the stellar mass limit of the
sample, with more massive galaxies showing a higher clustering amplitude on all
scales. We further interpret our clustering measurements in the LCDM
cosmological context using the halo model of galaxy clustering. We show that
the typical halo mass of central and satellite galaxies increases with stellar
mass, whereas the satellite fraction decreases with stellar mass, qualitatively
the same as is seen at z < 1. We see little evidence of any redshift dependence
in the stellar mass-to-halo mass relationship over our narrow redshift range.
However, when we compare with similar measurements at z~0, we see clear
evidence for a change in this relation. If we assume a universal baryon
fraction, the ratio of stellar mass to halo mass reveals the fraction of
baryons that have been converted to stars. We see that the peak in this star
formation efficiency for central galaxies shifts to higher halo masses at
higher redshift, moving from ~7x10^11 Msun at z~0 to ~3x10^12 Msun at z~1.5,
revealing evidence of `halo downsizing'. Finally we show that for highly biased
galaxy populations at z > 1 there may be a discrepancy between the measured
space density and clustering and that predicted by the halo model. This could
imply that there is a problem with one or more ingredients of the halo model at
these redshifts, for instance the halo bias relation or the halo profile.Comment: Accepted for publication in ApJ. Correction made to typo in halo
masses in conclusion
Mre11 modulates the fidelity of fusion between short telomeres in human cells
The loss of telomere function can result in the fusion of telomeres with other telomeric loci, or non-telomeric double-stranded DNA breaks. Sequence analysis of fusion events between short dysfunctional telomeres in human cells has revealed that fusion is characterized by a distinct molecular signature consisting of extensive deletions and micro-homology at the fusion points. This signature is consistent with alternative error-prone end-joining processes. We have examined the role that Mre11 may play in the fusion of short telomeres in human cells; to do this, we have analysed telomere fusion events in cells derived from ataxia-telangiectasia-like disorder (ATLD) patients that exhibit hypomorphic mutations in MRE11. The telomere dynamics of ATLD fibroblasts were indistinguishable from wild-type fibroblasts and they were proficient in the fusion of short telomeres. However, we observed a high frequency of insertion of DNA sequences at the fusion points that created localized sequence duplications. These data indicate that Mre11 plays a role in the fusion of short dysfunctional telomeres in human cells and are consistent with the hypothesis that as part of the MRN complex it serves to stabilize the joining complex, thereby controlling the fidelity of the fusion reaction
Management of asthma in pregnant women by general practitioners: A cross sectional survey
<p>Abstract</p> <p>Background</p> <p>Poorly controlled asthma can lead to maternal and fetal complications. Despite the known risks of poorly controlled asthma during pregnancy and the need for stepping up therapy when appropriate, there are concerns that management is suboptimal in primary care.</p> <p>Our objective was to investigate the management of asthma during pregnancy by general practitioners providing shared maternity care.</p> <p>Methods</p> <p>A pre-piloted, anonymous mail survey was sent to all general practitioners (n = 842) involved in shared maternity care at six maternity hospitals in Victoria, Australia. Respondents were asked about their perceived safety of individual asthma medications during pregnancy. Approach to asthma management during pregnancy was further explored using scenarios of pregnant women with stable and deteriorating asthma and poor medication adherence.</p> <p>Results</p> <p>Inhaled corticosteroids (ICS) were perceived to be the safest and were the preferred preventive medication in first trimester (74.1%), whilst leukotriene receptor antagonists were the least preferred (2.9%). A quarter (25.8%) of respondents would stop or decrease patients' ICS doses during pregnancy, even when their asthma was well controlled by current therapy. In addition, 12.1% of respondents were not sure how to manage deteriorating asthma during pregnancy and opted to refer to another health professional. Almost half the respondents (48.9%) reported encountering medication nonadherence during pregnancy.</p> <p>Conclusion</p> <p>A lack of confidence and/or knowledge among general practitioners in managing deteriorating asthma in pregnancy was observed despite a good understanding of the safety of asthma medications during pregnancy, compliance with evidence-based guidelines in the selection of preventive medications, and self reported good asthma knowledge.</p
Toxic gas removal – metal–organic frameworks for the capture and degradation of toxic gases and vapours
The release of anthropogenic toxic pollutants into the atmosphere is a worldwide threat of growing
concern. In this regard, it is possible to take advantage of the high versatility of MOFs materials in order
to develop new technologies for environmental remediation purposes. Consequently, one of the main
scientific challenges to be achieved in the field of MOF research should be to maximize the
performance of these solids towards the sensing, capture and catalytic degradation of harmful gases
and vapors by means of a rational control of size and reactivity of the pore walls that are directly
accessible to guest molecules.The authors are grateful for the generous support by the
Spanish Ministries of Economy (project: CTQ2011-22787) and
Defense (COINCIDENTE Program) as well as Junta de Andalucia
(P09-FQM-4981)
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