11,379 research outputs found
Circuit prevents overcharging of secondary cell batteries
Circuit prevents battery cell overcharging by detecting and reducing the charging voltage to the open-circuit voltage of the battery when this current falls to a predetermined value. The voltage control depends on the fact that the charging current falls significantly when the battery nears its fully charged state
Method and apparatus for battery charge control Patent
Battery charging system with cell to cell voltage balanc
Computational studies of light acceptance and propagation in straight and curved multimodal active fibres
A Monte Carlo simulation has been performed to track light rays in
cylindrical multimode fibres by ray optics. The trapping efficiencies for skew
and meridional rays in active fibres and distributions of characteristic
quantities for all trapped light rays have been calculated. The simulation
provides new results for curved fibres, where the analytical expressions are
too complex to be solved. The light losses due to sharp bending of fibres are
presented as a function of the ratio of curvature to fibre radius and bending
angle. It is shown that a radius of curvature to fibre radius ratio of greater
than 65 results in a light loss of less than 10% with the loss occurring in a
transition region at bending angles of pi/8 rad.Comment: 21 pages, 13 figure
Rabi oscillations under ultrafast excitation of graphene
We study coherent nonlinear dynamics of carriers under ultrafast interband
excitation of an intrinsic graphene. The Rabi oscillations of response appear
with increasing of pumping intensity. The photoexcited distribution is
calculated versus time and energy taking into account the effects of energy
relaxation and dephasing. Spectral and temporal dependencies of the response on
a probe radiation (transmission and reflection coefficients) are considered for
different pumping intensities and the Rabi oscillations versus time and
intensity are analyzed.Comment: 6 pages, 6 figure
Random Matrix Theory Analysis of Cross Correlations in Financial Markets
We confirm universal behaviors such as eigenvalue distribution and spacings
predicted by Random Matrix Theory (RMT) for the cross correlation matrix of the
daily stock prices of Tokyo Stock Exchange from 1993 to 2001, which have been
reported for New York Stock Exchange in previous studies. It is shown that the
random part of the eigenvalue distribution of the cross correlation matrix is
stable even when deterministic correlations are present. Some deviations in the
small eigenvalue statistics outside the bounds of the universality class of RMT
are not completely explained with the deterministic correlations as proposed in
previous studies. We study the effect of randomness on deterministic
correlations and find that randomness causes a repulsion between deterministic
eigenvalues and the random eigenvalues. This is interpreted as a reminiscent of
``level repulsion'' in RMT and explains some deviations from the previous
studies observed in the market data. We also study correlated groups of issues
in these markets and propose a refined method to identify correlated groups
based on RMT. Some characteristic differences between properties of Tokyo Stock
Exchange and New York Stock Exchange are found.Comment: RevTex, 17 pages, 8 figure
Talk like an expert: The construction of expertise in news comments concerning climate change
This article explores how readers of UK newspapers construct expertise around climate change. It draws on 300 online readers’ comments on news items in The Guardian, Daily Mail and The Telegraph, concerning the release of the International Panel on Climate Change report calling for immediate action on climate change. Comments were analysed using discursive psychology. We identified a series of discursive strategies that commenters adopted to present themselves as experts in their commentary. The (mostly indirect) use of category entitlements (implicitly claiming themselves as expert) and the presentation of one’s argument as factual (based on direct or indirect technical knowledge or common sense) emerged as common ways in which readers made claims to expertise, both among the supporters and among the sceptics of climate change science. Our findings indicate that expertise is a fluid concept, constructed in diverse ways, with important implications for public engagement with climate change science
High-speed photometry of the eclipsing polar UZ Fornacis
We present 33 new mid-eclipse times spanning approximately eight years of the
eclipsing polar UZ Fornacis. We have used our new observations to test the
two-planet model previously proposed to explain the variations in its eclipse
times measured over the past 35 years. We find that the proposed model
does indeed follow the general trend of the new eclipse times, however, there
are significant departures. In order to accommodate the new eclipse times, the
two-planet model requires that one or both of the planets require highly
eccentric orbits, that is, 0.4. Such multiple planet orbits are
considered to be unstable. Whilst our new observations are consistent with two
cyclic variations as previously predicted, significant residuals remain. We
conclude that either additional cyclic terms, possibly associated with more
planets, or other mechanisms, such as the Applegate mechanism are contributing
to the eclipse time variations. Further long-term monitoring is required.Comment: 11 pages, 5 figures, Accepted for publication in A&
Homologous and heterologous desensitization of guanylyl cyclase-B signaling in GH3 somatolactotropes
The guanylyl cyclases, GC-A and GC-B, are selective receptors for atrial and C-type natriuretic peptides (ANP and CNP, respectively). In the anterior pituitary, CNP and GC-B are major regulators of cGMP production in gonadotropes and yet mouse models of disrupted CNP and GC-B indicate a potential role in growth hormone secretion. In the current study, we investigate the molecular and pharmacological properties of the CNP/GC-B system in somatotrope lineage cells. Primary rat pituitary and GH3 somatolactotropes expressed functional GC-A and GC-B receptors that had similar EC50 properties in terms of cGMP production. Interestingly, GC-B signaling underwent rapid homologous desensitization in a protein phosphatase 2A (PP2A)-dependent manner. Chronic exposure to either CNP or ANP caused a significant down-regulation of both GC-A- and GC-B-dependent cGMP accumulation in a ligand-specific manner. However, this down-regulation was not accompanied by alterations in the sub-cellular localization of these receptors. Heterologous desensitization of GC-B signaling occurred in GH3 cells following exposure to either sphingosine-1-phosphate or thyrotrophin-releasing hormone (TRH). This heterologous desensitization was protein kinase C (PKC)-dependent, as pre-treatment with GF109203X prevented the effect of TRH on CNP/GC-B signaling. Collectively, these data indicate common and distinct properties of particulate guanylyl cyclase receptors in somatotropes and reveal that independent mechanisms of homologous and heterologous desensitization occur involving either PP2A or PKC. Guanylyl cyclase receptors thus represent potential novel therapeutic targets for treating growth-hormone-associated disorders
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