2,302 research outputs found
Geometric phase for neutrino propagation in magnetic field
The geometric phase for neutrinos propagating in an adiabatically varying
magnetic field in matter is calculated. It is shown that for neutrino
propagation in sufficiently large magnetic field the neutrino eigenstates
develop a significant geometric phase. The geometric phase varies from 2
for magnetic fields fraction of a micro gauss to for fields gauss or more. The variation of geometric phase with magnetic field
parameters is shown and its phenomenological implications are discussed
Growth and Characterization of Iron-Managenese Mixed Tartrate Crystals and the Derivative Compounds
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Suitability of Various Substrates for Cultivation of Pleurotus Pulmonarius in Konkan Region of Maharashtra
Mild tropical humid climate persists in Konkan region throughout the year within a range of 23 - 35 0 C. This climate is conducive for the commercial cultivation of oyster mushroom. Locally available substrates such as paddy straw, arecanut husk, coconut husk, banana pseudostem, groundnut shells, sugarcane bagasse and wheat straw alone and in combination with rice bran and wheat bran were used. Maximum biological efficiency of P. pulmonarius was recorded on paddy straw (76.30%) followed by wheat straw (74. 53 %). In case of supplemented substrates, the maximum biological efficiency of the mushroom was recorded on paddy straw supplemented with wheat bran (85.40%). This was followed by paddy straw supplemented with rice bran (82.63%) and wheat straw supplemented with wheat bran (82.26)
Influence of defect pairs in Ga-based ordered defect compounds: a hybrid density functional study
In the present paper, density functional theory (DFT) based calculations have been performed to predict the stability, electronic, and optical properties of Ga-rich ordered defect compounds (ODCs). The calculated lattice constants, bulk modulus, their pressure derivatives, and optical constants show good agreement with available experimental data. The hybrid exchange correlations functional have been considered to calculate ground state total energy and energy band gap of the material. The calculated formation energy of ODCs comes smaller than pure CuGaSe2 (CGS). Our calculated optical absorption coefficients indicate that the energy band gap of ODCs can be tuned by changing the number of donor-acceptor defect pairs (2V(cu)(-), + Ga-cu(2+)). The band offset has been calculated to understand the reason of band gap alteration while the number of defect pair changes. Our results may be helpful for other experiments to further improve the performance of ODCs
The saga of atomic weights
Who were the first people to think of the concept of atomic weights? How were atomic weights of elements first calculated? In this article, the authors explore the long scientific journey from the origins of the widely used conceptual framework of atomic weights to the debates on the topic prevalent even today
Evaluating XGBoost for Balanced and Imbalanced Data: Application to Fraud Detection
This paper evaluates XGboost's performance given different dataset sizes and
class distributions, from perfectly balanced to highly imbalanced. XGBoost has
been selected for evaluation, as it stands out in several benchmarks due to its
detection performance and speed. After introducing the problem of fraud
detection, the paper reviews evaluation metrics for detection systems or binary
classifiers, and illustrates with examples how different metrics work for
balanced and imbalanced datasets. Then, it examines the principles of XGBoost.
It proposes a pipeline for data preparation and compares a Vanilla XGBoost
against a random search-tuned XGBoost. Random search fine-tuning provides
consistent improvement for large datasets of 100 thousand samples, not so for
medium and small datasets of 10 and 1 thousand samples, respectively. Besides,
as expected, XGBoost recognition performance improves as more data is
available, and deteriorates detection performance as the datasets become more
imbalanced. Tests on distributions with 50, 45, 25, and 5 percent positive
samples show that the largest drop in detection performance occurs for the
distribution with only 5 percent positive samples. Sampling to balance the
training set does not provide consistent improvement. Therefore, future work
will include a systematic study of different techniques to deal with data
imbalance and evaluating other approaches, including graphs, autoencoders, and
generative adversarial methods, to deal with the lack of labels.Comment: 17 pages, 8 figures, 9 tables, Presented at NVIDIA GTC, The
Conference for the Era of AI and the Metaverse, March 23, 2023. [S51129
Drosophila PSI controls circadian period and the phase of circadian behavior under temperature cycle via tim splicing
The Drosophila circadian pacemaker consists of transcriptional feedback loops subjected to post-transcriptional and post-translational regulation. While post-translational regulatory mechanisms have been studied in detail, much less is known about circadian post-transcriptional control. Thus, we targeted 364 RNA binding and RNA associated proteins with RNA interference. Among the 43 hits we identified was the alternative splicing regulator P-element somatic inhibitor (PSI). PSI regulates the thermosensitive alternative splicing of timeless (tim), promoting splicing events favored at warm temperature over those increased at cold temperature. Psi downregulation shortens the period of circadian rhythms and advances the phase of circadian behavior under temperature cycle. Interestingly, both phenotypes were suppressed in flies that could produce TIM proteins only from a transgene that cannot form the thermosensitive splicing isoforms. Therefore, we conclude that PSI regulates the period of Drosophila circadian rhythms and circadian behavior phase during temperature cycling through its modulation of the tim splicing pattern
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