385 research outputs found
Low-Temperature Permittivity of Insulating Perovskite Manganites
Measurements of the low-frequency (f<=100 kHz) permittivity and conductivity
at T<= 150 K are reported for La(1-x)Ca(x)MnO(3) (0<=x<=1) and
Ca(1-y)Sr(y)MnO(3) (0<=y<=0.75) having antiferromagnetic, insulating ground
states covering a broad range of Mn valencies from Mn(3+) to Mn(4+). Static
dielectric constants are determined from the low-T limiting behavior. With
increasing T, relaxation peaks associated with charge-carrier hopping are
observed in the real part of the permittivities and analyzed to determine
dopant binding energies. The data are consistent with a simple model of
hydrogenic impurity levels and imply effective masses m*/m_e~3 for the Mn(4+)
compounds. Particularly interesting is a large dielectric constant (~100)
associated with the C-type antiferromagnetic state near the composition
La(0.2)Ca(0.8)MnO(3).Comment: 6 pages, 8 figures, PRB in pres
Note on the unusual landings of Amblygaster sirm off Vizhinjam coast
Unusual landings of the clupeid Amblygaster sirm(spotted sardinella), was noticed during the October– December 2016 along the Vizhinjam coast. Locallyknown as Keerichala, regular landings of A. sirmwas observed in all the major landing centres alongthe Thiruvananthapuram coast like Mampally,Anjengo, Perumathura, Thazhampally, Marianad,Valiyathura, Poonthura etc
Length-weight, length-length relationships and condition factor of obtuse barracuda Sphyraena obtusata Cuvier, 1829 (Pisces: Perciformes) from Vizhinjam coast, Kerala, India
Eleven morphometric variables including weight were recorded for 429 specimens of obtuse barracuda Sphyraena obtusata Cuvier, 1829 collected over a period of two years from January 2017 to December 2018, from Vizhinjam fish landing centre, Thiruvananthapuram, Kerala. Length-weight relationship and length-length relationship of the species were estimated using linear regression analysis. Different length measurements were converted to ratios with standard length as morphometric ratios and the growth rate was assessed gender wise. Length-weight relationship for male and female population were estimated as Wm= 13.326 × L3.2409 and Wf = 11.952 × L2.9821, respectively. Linear relationships for other morphometric variables and morphometric ratios with standard length were established for the species. Principal component analysis was performed and total length, snout length and snout to pre-nostril length were identified as key morphometric variables discriminating gender. The relative condition factor was estimated as 1.04+0.13 for total population and the role of morphometric ratios in sex differentiation was examined
Decentralised agrobiodiversity conservation: A multi stakeholder participatory experiment
Cultivated plant species and domesticated animal species, including their genetic variants and associated plant and animal diversity, are collectively called ‘agrobiodiversity’. These resources are at risk with the expansion of industrial agriculture, and maintaining locally adapted native seed materials in micro agro-ecosystems will be vital for ensuring crop resilience to climate change. This study narrates the learning experiences of a 3-year participatory project – Networking traditional farmers and local self-governments for agro-biodiversity conservation and Wayanad community seed festival – implemented with local communities and local governments.
The aim of the project was to democratise agrobiodiversity
conservation efforts through a seed conservation movement
in the Wayanad district of Kerala, India
AutoML accurately predicts endovascular mechanical thrombectomy in acute large vessel ischemic stroke
Background and objectiveAutomated machine learning or autoML has been widely deployed in various industries. However, their adoption in healthcare, especially in clinical settings is constrained due to a lack of clear understanding and explainability. The aim of this study is to utilize autoML for the prediction of functional outcomes in patients who underwent mechanical thrombectomy and compare it with traditional ML models with a focus on the explainability of the trained models.MethodsA total of 156 patients of acute ischemic stroke with Large Vessel Occlusion (LVO) who underwent mechanical thrombectomy within 24 h of stroke onset were included in the study. A total of 34 treatment variables including clinical, demographic, imaging, and procedure-related data were extracted. Various conventional machine learning models such as decision tree classifier, logistic regression, random forest, kNN, and SVM as well as various autoML models such as AutoGluon, MLJAR, Auto-Sklearn, TPOT, and H2O were used to predict the modified Rankin score (mRS) at the time of patient discharge and 3 months follow-up. The sensitivity, specificity, accuracy, and AUC for traditional ML and autoML models were compared.ResultsThe autoML models outperformed the traditional ML models. For the prediction of mRS at discharge, the highest testing accuracy obtained by traditional ML models for the decision tree classifier was 74.11%, whereas for autoML which was obtained through AutoGluon, it showed an accuracy of 88.23%. Similarly, for mRS at 3 months, the highest testing accuracy of traditional ML was that of the SVM classifier at 76.5%, whereas that of autoML was 85.18% obtained through MLJAR. The 24-h ASPECTS score was the most important predictor for mRS at discharge whereas for prediction of mRS at 3 months, the most important factor was mRS at discharge.ConclusionAutomated machine learning models based on multiple treatment variables can predict the functional outcome in patients more accurately than traditional ML models. The ease of clinical coding and deployment can assist clinicians in the critical decision-making process. We have developed a demo application which can be accessed at https://mrs-score-calculator.onrender.com/
Evidence of a new shell closed nucleus governing slow quasi-fission
Mass distributions of fission fragments arising from the slow quasi-fission
process have been derived by comparing the measured distributions with the
theoretical distributions based on compound nuclear fission model for several
reactions. The mass-distributions corresponding to quasi-fission events for all
the systems show the following common features: (1) they are double peaked with
fixed peak-centroids and nearly same width at different incident energies, (2)
the yield of quasi-fission events decreases with the increasing projectile
energy, and (3) peak corresponding to lighter fragment is observed at A
96 for all the systems, whereas the peak of heavier fragment increases linearly
with the mass of the di-nuclear system. All the above observations are quite
similar to the ones observed in well known asymmetric fission of actinides,
thus providing clear evidences of shell effect in slow quasi-fission where the
lighter fragment is possibly nuclei around Zr, a new doubly magic
nucleus. This finding has great implications in the study of nuclear reactions,
structure and particularly in super-heavy element synthesis where quasi-fission
is synonymous
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