173 research outputs found
Angiotensin II Type 1 Receptors and Systemic Hemodynamic and Renal Responses to Stress and Altered Blood Volume in Conscious Rabbits
We examined how systemic blockade of type 1 angiotensin (AT1-) receptors affects reflex control of the circulation and the kidney. In conscious rabbits, the effects of candesartan on responses of systemic and renal hemodynamics and renal excretory function to acute hypoxia, mild hemorrhage, and plasma volume expansion were tested. Candesartan reduced resting mean arterial pressure (MAP, −8 ± 2%) without significantly altering cardiac output (CO), increased renal blood flow (RBF, +38 ± 9%) and reduced renal vascular resistance (RVR, −32 ± 6%). Glomerular filtration rate (GFR) was not significantly altered but sodium excretion (UNa+V) increased fourfold. After vehicle treatment, hypoxia (10% inspired O2 for 30 min) did not significantly alter MAP or CO, but reduced heart rate (HR, −17 ± 6%), increased RVR (+33 ± 16%) and reduced GFR (−46 ± 16%) and UNa+V (−41 ± 17%). Candesartan did not significantly alter these responses. After vehicle treatment, plasma volume expansion increased CO (+35 ± 7%), reduced total peripheral resistance (TPR, −26 ± 5%), increased RBF (+62 ± 23%) and reduced RVR (−32 ± 9%), but did not significantly alter MAP or HR. It also increased UNa+V (803 ± 184%) yet reduced GFR (−47 ± 9%). Candesartan did not significantly alter these responses. After vehicle treatment, mild hemorrhage did not significantly alter MAP but increased HR (+16 ± 3%), reduced CO (−16 ± 4%) and RBF (−18 ± 6%), increased TPR (+18 ± 4%) and tended to increase RVR (+18 ± 9%, P = 0.1), but had little effect on GFR or UNa+V. But after candesartan treatment MAP fell during hemorrhage (−19 ± 1%), while neither TPR nor RVR increased, and GFR (−64 ± 18%) and UNa+V (−83 ± 10%) fell. AT1-receptor activation supports MAP and GFR during hypovolemia. But AT1-receptors appear to play little role in the renal vasoconstriction, hypofiltration, and antinatriuresis accompanying hypoxia, or the systemic and renal vasodilatation and natriuresis accompanying plasma volume expansion
Predicting the Future of AI with AI: High-quality link prediction in an exponentially growing knowledge network
A tool that could suggest new personalized research directions and ideas by taking insights from the scientific literature could significantly accelerate the progress of science. A field that might benefit from such an approach is artificial intelligence (AI) research, where the number of scientific publications has been growing exponentially over the last years, making it challenging for human researchers to keep track of the progress. Here, we use AI techniques to predict the future research directions of AI itself. We develop a new graph-based benchmark based on real-world data -- the Science4Cast benchmark, which aims to predict the future state of an evolving semantic network of AI. For that, we use more than 100,000 research papers and build up a knowledge network with more than 64,000 concept nodes. We then present ten diverse methods to tackle this task, ranging from pure statistical to pure learning methods. Surprisingly, the most powerful methods use a carefully curated set of network features, rather than an end-to-end AI approach. It indicates a great potential that can be unleashed for purely ML approaches without human knowledge. Ultimately, better predictions of new future research directions will be a crucial component of more advanced research suggestion tools
Sensitivity, specificity, and diagnostic accuracy of WHO 2013 criteria for diagnosis of gestational diabetes mellitus in low risk early pregnancies: international, prospective, multicentre cohort study
Objective: To evaluate the predictability of gestational diabetes mellitus wth a 75 g oral glucose tolerance test (OGTT) in early pregnancy, based on the 2013 criteria of the World Health Organization, and to test newly proposed cut-off values.
Design: International, prospective, multicentre cohort study.SettingSix university or cantonal departments in Austria, Germany, and Switzerland, from 1 May 2016 to 31 January 2019.ParticipantsLow risk cohort of 829 participants aged 18-45 years with singleton pregnancies attending first trimester screening and consenting to have an early 75 g OGTT at 12-15 weeks of gestation. Participants and healthcare providers were blinded to the results.
Main outcome measures: Fasting, one hour, and two hour plasma glucose concentrations after an early 75 g OGTT (12-15 weeks of gestation) and a late 75 g OGTT (24-28 weeks of gestation).
Results: Of 636 participants, 74 (12%) developed gestational diabetes mellitus, according to World Health Organization 2013 criteria, at 24-28 weeks of gestation. Applying WHO 2013 criteria to the early OGTT with at least one abnormal value gave a low sensitivity of 0.35 (95% confidence interval 0.24 to 0.47), high specificity of 0.96 (0.95 to 0.98), positive predictive value of 0.57 (0.41 to 0.71), negative predictive value of 0.92 (0.89 to 0.94), positive likelihood ratio of 10.46 (6.21 to 17.63), negative likelihood ratio of 0.65 (0.55 to 0.78), and diagnostic odds ratio of 15.98 (8.38 to 30.47). Lowering the postload glucose values (75 g OGTT cut-off values of 5.1, 8.9, and 7.8 mmol/L) improved the detection rate (53%, 95% confidence interval 41% to 64%) and negative predictive value (0.94, 0.91 to 0.95), but decreased the specificity (0.91, 0.88 to 0.93) and positive predictive value (0.42, 0.32 to 0.53) at a false positive rate of 9% (positive likelihood ratio 5.59, 4.0 to 7.81; negative likelihood ratio 0.64, 0.52 to 0.77; and diagnostic odds ratio 10.07, 6.26 to 18.31).
Conclusions: The results of this prospective low risk cohort study indicated that the 75 g OGTT as a screening tool in early pregnancy is not sensitive enough when applying WHO 2013 criteria. Postload glucose values were higher in early pregnancy complicated by diabetes in pregnancy. Lowering the postload cut-off values identified a high risk group for later development of gestational diabetes mellitus or those who might benefit from earlier treatment. Results from randomised controlled trials showing a beneficial effect of early intervention are unclear.
Trial registrationClinicalTrials.govNCT02035059
Gamow Shell Model Description of Weakly Bound Nuclei and Unbound Nuclear States
We present the study of weakly bound, neutron-rich nuclei using the nuclear
shell model employing the complex Berggren ensemble representing the bound
single-particle states, unbound Gamow states, and the non-resonant continuum.
In the proposed Gamow Shell Model, the Hamiltonian consists of a one-body
finite depth (Woods-Saxon) potential and a residual two-body interaction. We
discuss the basic ingredients of the Gamow Shell Model. The formalism is
illustrated by calculations involving {\it several} valence neutrons outside
the double-magic core: He and O.Comment: 19 pages, 20 encapsulated PostScript figure
Normal cervical changes in parous women during the second half of pregnancy - a prospective, longitudinal ultrasound study
OBJECTIVE: To determine what constitutes normal cervical changes during the second half of pregnancy in parous women delivering at term. DESIGN: The study comprises 21 healthy, pregnant parous women who all gave birth at term. They were examined with transvaginal ultrasound every two weeks from 24 gestational weeks until delivery. Cervical length and width were measured. The inner cervical os was assessed as being closed or open, the length and width of any opening were measured, and dynamic cervical changes (i.e. opening and closing of the inner cervical os during examination) were noted. RESULTS: Median cervical length was 41 mm (range 26-55) at the first examination and 29 mm (range 8-56) at the last examination. The corresponding figures for cervical width were 38 mm (range 29-47) and 46 mm (range 38-64). Cervical length decreased in 18 women but remained unchanged in three. Three patterns of change in cervical length were observed: in 12 women there was a steady, continuous decrease in cervical length (median decrease rate 1.1 mm/week, range 0.6-2.4); in four women the decrease rate accelerated towards the end of pregnancy, the median decrease rate after the change being 3.0 mm/week (range 1.5-4.8); and in two women there was a sudden drop in cervical length at term. Cervical width increased in 16 women but remained unchanged in five. Two patterns of change in cervical width were seen: 14 women manifested a steady continuous increase in cervical width (median 0.8 mm/week, range 0.4-1.8); in two women the increase rate accelerated from around 34 gestational weeks, the increase rate after the change being 4.1 and 5.9 mm/week, respectively. Opening of the internal cervical os was observed at least once in 11 (52%) women and was seen as early as at 24 and 25 gestational weeks in two women. The opening was always V-shaped (median length 6 mm, range 4-17; median width 7 mm, range 3-20). Dynamic changes of the internal cervical os were seen in three women (14%) at 25, 30 and 41 gestational weeks, respectively. CONCLUSION: The cervix of parous women decreases in length and increases in width from midpregnancy to term, but the pattern of change varies between individuals. Knowledge of the different patterns of normal change forms the basis of transvaginal ultrasound studies of pathological cervical changes during pregnancy
A prognostic tool to identify adolescents at high risk of becoming daily smokers
<p>Abstract</p> <p>Background</p> <p>The American Academy of Pediatrics advocates that pediatricians should be involved in tobacco counseling and has developed guidelines for counseling. We present a prognostic tool for use by health care practitioners in both clinical and non-clinical settings, to identify adolescents at risk of becoming daily smokers.</p> <p>Methods</p> <p>Data were drawn from the Nicotine Dependence in Teens (NDIT) Study, a prospective investigation of 1293 adolescents, initially aged 12-13 years, recruited in 10 secondary schools in Montreal, Canada in 1999. Questionnaires were administered every three months for five years. The prognostic tool was developed using estimated coefficients from multivariable logistic models. Model overfitting was corrected using bootstrap cross-validation. Goodness-of-fit and predictive ability of the models were assessed by R<sup>2</sup>, the c-statistic, and the Hosmer-Lemeshow test.</p> <p>Results</p> <p>The 1-year and 2-year probability of initiating daily smoking was a joint function of seven individual characteristics: age; ever smoked; ever felt like you needed a cigarette; parent(s) smoke; sibling(s) smoke; friend(s) smoke; and ever drank alcohol. The models were characterized by reasonably good fit and predictive ability. They were transformed into user-friendly tables such that the risk of daily smoking can be easily computed by summing points for responses to each item. The prognostic tool is also available on-line at <url>http://episerve.chumontreal.qc.ca/calculation_risk/daily-risk/daily_smokingadd.php</url>.</p> <p>Conclusions</p> <p>The prognostic tool to identify youth at high risk of daily smoking may eventually be an important component of a comprehensive tobacco control system.</p
TELAMON: Effelsberg Monitoring of AGN Jets with Very-High-Energy Astroparticle Emissions -- II. Polarization properties
We present recent results of the TELAMON program, which is using the
Effelsberg 100-m telescope to monitor the radio spectra of active galactic
nuclei (AGN) under scrutiny in astroparticle physics, namely TeV blazars and
neutrino-associated AGN. Our sample includes all known Northern TeV-emitting
blazars as well as blazars positionally coincident with IceCube neutrino
alerts. Polarization can give additional insight into the source properties, as
the polarized emission is often found to vary on different timescales and
amplitudes than the total intensity emission. Here, we present an overview of
the polarization properties of the TeV-emitting TELAMON sources at four
frequencies in the 20 mm and 7 mm bands. While at 7 mm roughly of all
observed sources are found to be significantly polarized, for 20 mm the
percentage is . We find that most of the sources exhibit mean
fractional polarizations of , matching the expectations of rather low
polarization levels in these sources from previous studies at lower radio
frequencies. Nevertheless, we demonstrate examples of how the polarized
emission can provide additional information over the total intensity.Comment: 9 pages, 2 figures, Proceedings of the 38th International Cosmic Ray
Conference (ICRC2023
Householders’ Mental Models of Domestic Energy Consumption: Using a Sort-And-Cluster Method to Identify Shared Concepts of Appliance Similarity
If in-home displays and other interventions are to successfully influence people's energy consumption, they need to communicate about energy in terms that make sense to users. Here we explore householders' perceptions of energy consumption, using a novel combination of card-sorting and clustering to reveal shared patterns in the way people think about domestic energy consumption. The data suggest that, when participants were asked to group appliances which they felt naturally 'went together', there are relatively few shared ideas about which appliances are conceptually related. To the extent participants agreed on which appliances belonged together, these groupings were based on activities (e.g., entertainment) and location within the home (e.g., kitchen); energy consumption was not an important factor in people's categorisations. This suggests messages about behaviour change aimed at reducing energy consumption might better be tied to social practices than to consumption itself
Making a Step Forward Towards Urban Resilience. The Contribution of Digital Innovation
Starting from 'wicked problem' theory as the landmark for framing disaster events in terms of policy issue for city governments, this paper highlights the contribution provided by Big Data analytics and digital innovation in dealing with disaster risks. The research aims at answering the following question: what is the role that 'smart technologies' play in strengthening urban resilience to disaster risks
Applying behavioural theory to the challenge of sustainable development: using hairdressers as diffusers of more sustainable hair-care practices
The challenges presented by sustainable development are broadly accepted, yet resource use increases unabated. It is increasingly acknowledged that while technical solutions may play a part, a key issue is behaviour change. In response to this there has been a plethora of studies into how behaviour change can be enabled, predominantly from psychological and sociological perspectives. This has resulted in a substantial body of knowledge into the factors that drive behaviour change and how they can be manipulated to achieve desired social goals. In this paper we describe a study that draws on this body of knowledge to design an intervention to drive behaviour change across the hairdressing sector, and by the process of diffusion, across the vast social networks of this occupational group to influence domestic hair-care practices. The intervention was successful: hairdressers indicated positive intentions to adopt more sustainable practices within their salons and pass them onto their customers. The customer survey (N=776) confirms this: customers surveyed after their hairdresser attended the Green-Salon-Makeover intervention were significantly more likely to report that environmental issues had been considered in their salon visit and that they themselves would consider such issues in their hair-care practices at home than customers who were surveyed before the intervention
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