4,613 research outputs found
A new study of Mg(,n)Si angular distributions at = 3 - 5 MeV
The observation of Al gives us the proof of active nucleosynthesis in
the Milky Way. However the identification of the main producers of Al is
still a matter of debate. Many sites have been proposed, but our poor knowledge
of the nuclear processes involved introduces high uncertainties. In particular,
the limited accuracy on the Mg(,n)Si reaction cross
section has been identified as the main source of nuclear uncertainty in the
production of Al in C/Ne explosive burning in massive stars, which has
been suggested to be the main source of Al in the Galaxy. We studied
this reaction through neutron spectroscopy at the CN Van de Graaff accelerator
of the Legnaro National Laboratories. Thanks to this technique we are able to
discriminate the (,n) events from possible contamination arising from
parasitic reactions. In particular, we measured the neutron angular
distributions at 5 different beam energies (between 3 and 5 MeV) in the
\ang{17.5}-\ang{106} laboratory system angular range. The presented results
disagree with the assumptions introduced in the analysis of a previous
experiment.Comment: 9 pages, 9 figures - accepted by EPJ
Fullerenes as adhesive layers for mechanical peeling of metallic, molecular and polymer thin films
We show that thin films of C60 with a thickness ranging from 10 to 100 nm can promote adhesion between a Au thin film deposited on mica and a solution-deposited layer of the elastomer polymethyldisolaxane (PDMS). This molecular adhesion facilitates the removal of the gold film from the mica support by peeling and provides a new approach to template stripping which avoids the use of conventional adhesive layers. The fullerene adhesion layers may also be used to remove organic monolayers and thin films as well as two-dimensional polymers which are pre-formed on the gold surface and have monolayer thickness. Following the removal from the mica support the monolayers may be isolated and transferred to a dielectric surface by etching of the gold thin film, mechanical transfer and removal of the fullerene layer by annealing/dissolution. The use of this molecular adhesive layer provides a new route to transfer polymeric films from metal substrates to other surfaces as we demonstrate for an assembly of covalently-coupled porphyrins
FSL-BM: Fuzzy Supervised Learning with Binary Meta-Feature for Classification
This paper introduces a novel real-time Fuzzy Supervised Learning with Binary
Meta-Feature (FSL-BM) for big data classification task. The study of real-time
algorithms addresses several major concerns, which are namely: accuracy, memory
consumption, and ability to stretch assumptions and time complexity. Attaining
a fast computational model providing fuzzy logic and supervised learning is one
of the main challenges in the machine learning. In this research paper, we
present FSL-BM algorithm as an efficient solution of supervised learning with
fuzzy logic processing using binary meta-feature representation using Hamming
Distance and Hash function to relax assumptions. While many studies focused on
reducing time complexity and increasing accuracy during the last decade, the
novel contribution of this proposed solution comes through integration of
Hamming Distance, Hash function, binary meta-features, binary classification to
provide real time supervised method. Hash Tables (HT) component gives a fast
access to existing indices; and therefore, the generation of new indices in a
constant time complexity, which supersedes existing fuzzy supervised algorithms
with better or comparable results. To summarize, the main contribution of this
technique for real-time Fuzzy Supervised Learning is to represent hypothesis
through binary input as meta-feature space and creating the Fuzzy Supervised
Hash table to train and validate model.Comment: FICC201
Money in monetary policy design: monetary cross-checking in the New-Keynesian model
In the New-Keynesian model, optimal interest rate policy under uncertainty is formulated without reference to monetary aggregates as long as certain standard assumptions on the distributions of unobservables are satisfied. The model has been criticized for failing to explain common trends in money growth and inflation, and that therefore money should be used as a cross-check in policy formulation (see Lucas (2007)). We show that the New-Keynesian model can explain such trends if one allows for the possibility of persistent central bank misperceptions. Such misperceptions motivate the search for policies that include additional robustness checks. In earlier work, we proposed an interest rate rule that is near-optimal in normal times but includes a cross-check with monetary information. In case of unusual monetary trends, interest rates are adjusted. In this paper, we show in detail how to derive the appropriate magnitude of the interest rate adjustment following a significant cross-check with monetary information, when the New-Keynesian model is the central bank’s preferred model. The cross-check is shown to be effective in offsetting persistent deviations of inflation due to central bank misperceptions. Keywords: Monetary Policy, New-Keynesian Model, Money, Quantity Theory, European Central Bank, Policy Under Uncertaint
Quantum singularity of Levi-Civita spacetimes
Quantum singularities in general relativistic spacetimes are determined by
the behavior of quantum test particles. A static spacetime is quantum
mechanically singular if the spatial portion of the wave operator is not
essentially self-adjoint. Here Weyl's limit point-limit circle criterion is
used to determine whether a wave operator is essentially self-adjoint. This
test is then applied to scalar wave packets in Levi-Civita spacetimes to help
elucidate the physical properties of the spacetimes in terms of their metric
parameters
Ozarkian seaweeds and oölites
p. 237-260, [6] leaves of plates : ill. ; 24 cm."Literature bearing on ancient seaweeds and the oölites": p. 256-257.Silicified seaweeds of the Conococheague. Fruit conceptacles of Crytozoön proliferum -- Conococheague oölites
Imaging of cardiac neuronal function after cocaine exposure using Carbon-11 hydroxyephedrine and positron emission tomography
AbstractObjectives. The aim of the study was to define the effect of cocaine on the myocardial uptake and retention of C-11 hydroxyephedrine in the anesthetized dog model.Background. Cardiac toxcity of cocaine has been linked to its inhibitory effect on norepinephrine reuptake by the sympathetic nerve terminals of the heart. Carbon-11 hydroxyephedrine is a C-11-labled norepinephrine analog that has high specific affinity for uptake-1 and thus makes possible the assessment of the effect of cocaine on norepinephrine reuptake by cardiac sympathetic nerve terminals.Methods. The cardiac kinetics of C-11 hydroxyephedrine as assessed by dynamic positron emission tomographic imaging were used to characterize norepinephrine reuptake by the sympathetic nerve terminals. Carbon-11 hydroxyephedrine was injected intravenously before, as well as at 5 min and 2.5 h after, intravenous administration of 2 mg/kg body weight of cocaine in anesthetized dogs. Hemodynamic variables and microsphere-determined cardiac blood flow were also measured before and after cocaine exposure.Results. Intravenous injection of cocaine did not significantly affect hemodynamic variables and myocardial blood flow in the anesthetized animals. Compared with baseline, myocardial retention of C-11 hydroxyephedrine was significantly reduced by 78 ± 3% (mean ± SD) at 5 min and remained significantly reduced (28 ± 17%) at 2.5 h after cocaine injection. Cocaine administration after C-11 hydroxyephedrine injection (39 min) resulted in rapid biexponential clearance of C-11 hydroxyephedrine from myocardium.Conclusions. These results suggest prolonged effects of cocaine on the sympathetic nerve terminals of the heart. Positron emission tomography provides a noninvasive and sensitive means to objectively assess the cardiac pharmacokinetics of drugs such as cocaine
Preventive herd management practices and their effect on lamb mortality in Ethiopia.
According to previous studies, lamb mortality is high in the Ethiopian highlands. The present study aims to evaluate the execution of preventive sheep herd health management practices with respect to if, and how, such practices are linked to occurrence of lamb mortality. Interviews were performed with 74 sheep-owning households participating in a capacity development program on livestock and 69 households not participating in such program. To evaluate the impact of combinations of performed practices, a scoring system was developed-the households retrieved a higher score the more desired routines were accomplished. To identify which practices had the highest impact on lamb mortality, a similar score was calculated for each phase of the sheep reproductive year, creating sub-scores for each phase. The results showed a significant (p < 0.05) negative correlation between the total number of performed practices and occurrence of lamb mortality, indicating a lower occurrence of lamb mortality the more desired practices implemented. Further analysis of sub-scores showed significant (p < 0.05) negative correlations between a higher number of performed desired practices during gestation period and during lambing. Conclusively, the study indicates that preventive herd management routines are beneficial for lamb survival, foremost when enforced during the gestation period and around lambing-hence, this is where to focus future interventions
Highly Efficient and Scalable Separation of Semiconducting Carbon Nanotubes via Weak Field Centrifugation
The identification of scalable processes that transfer random mixtures of single-walled carbon nanotubes (SWCNTs) into fractions featuring a high content of semiconducting species is crucial for future application of SWCNTs in high-performance electronics. Herein we demonstrate a highly efficient and simple separation method that relies on selective interactions between tailor-made amphiphilic polymers and semiconducting SWCNTs in the presence of low viscosity separation media. High purity individualized semiconducting SWCNTs or even self-organized semiconducting sheets are separated from an as-produced SWCNT dispersion via a single weak field centrifugation run. Absorption and Raman spectroscopy are applied to verify the high purity of the obtained SWCNTs. Furthermore SWCNT - network field-effect transistors were fabricated, which exhibit high ON/OFF ratios (10) and field-effect mobilities (17 cm/Vs). In addition to demonstrating the feasibility of high purity separation by a novel low complexity process, our method can be readily transferred to large scale production
Impact of Age on the Effectiveness and Safety of Insulin Glargine 300 U/mL: Results from the REALI European Pooled Data Analysis
Introduction: Patients aged ≥ 65 years continue to be underrepresented in clinical studies related to type 2 diabetes mellitus (T2DM). Accordingly, the REALI pooled analysis was performed to evaluate the effectiveness and safety of insulin glargine 300 U/mL (Gla-300) across different age subgroups, using data from 14 interventional and non-interventional studies. Methods: Pooled efficacy and safety data were collected from 8106 European patients with uncontrolled T2DM who were initiated on or switched to Gla-300 injected once daily for 24 weeks. Patients were categorised into five age subgroups: < 50 (N = 727), 50–59 (N = 2030), 60–69 (N = 3054), 70–79 (N = 1847) and ≥ 80 years (N = 448). Results: Mean baseline haemoglobin A1c (HbA1c) decreased linearly from the youngest (9.10%) to the oldest (8.46%) age subgroup. Following Gla-300 initiation, there were similar HbA1c reductions across age groups, with a least squares mean (95% confidence interval) change in HbA1c from baseline to week 24 of − 1.09% (− 1.18 to − 1.00), − 1.08% (− 1.14 to − 1.03), − 1.12% (− 1.17 to − 1.07), − 1.18% (− 1.24 to − 1.12) and − 1.11% (− 1.23 to − 0.99) in the < 50, 50–59, 60–69, 70–79 and ≥ 80 years subgroups, respectively. The incidences and event rates of reported hypoglycaemia were overall low. Compared to younger age subgroups, lower incidences of symptomatic hypoglycaemia occurring at any time of the day (5.9 vs. 7.6–9.4% for the younger subgroups) or during the night (0.5 vs. 1.6–2.5%) were recorded in patients aged ≥ 80 years. By contrast, the highest incidence of severe hypoglycaemia occurring any time of the day was reported in the subgroup aged ≥ 80 years (1.1 vs. 0.1–0.6% for the younger age subgroups). Conclusion: Gla-300 initiated in patients with uncontrolled T2DM provides glycaemic improvement with a favourable safety profile across a wide range of ages
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