Evolution of Crustal Magnetic Fields in Isolated Neutron Stars : Combined Effects of Cooling and Curvature of Space-time

The ohmic decay of magnetic fields confined within the crust of neutron stars is considered by incorporating both the effect of neutron star cooling and the effect of space-time curvature produced by the intense gravitational field of the star. For this purpose a stationary and static gravitational field has been considered with the standard as well as the accelerated cooling models of neutron stars. It is shown that general relativistic effect reduces the magnetic field decay rate substantially. At the late stage of evolution when the field decay is mainly determined by the impurity-electron scattering, the effect of space-time curvature suppresses the role of the impurity content significantly and reduces the decay rate by more than an order of magnitude. Even with a high impurity content the decay rate is too low to be of observational interest if the accelerated cooling model along with the effect of space-time curvature is taken into account. It is, therefore, pointed out that if a decrease in the magnetic field strength by more than two orders of magnitude from its initial value is detected by observation then the existence of quark in the core of the neutron star would possibly be ruled out.Comment: 15 pages, AAS LATEX macros v4.0, 5 postscript figures, Accepted for publication in the Astrophysical Journal (Part I

Topology Optimization of Beam Structures with Various End andLoading Conditions

Topology optimization deals with optimum material (mass) distribution within a design domain to find optimal lay-out of a structure subjected to certain boundary and loading conditions. Topology optimization can be used to address conflicting requirements, such as light weight and high-strength/stiffness design. In this paper, a simulation program to analyze topology optimization of beam structures with seven different end conditions and three types of loads (single point load, two point loads and uniformly distributed load) is developed using MATLAB code adapted from Sigmund’s 99 line topology optimization code. Furthermore, the program has been enhanced with a graphical user interface for ease of use. Using the developed system, it is possible to analyze the effect of different parameters

Familial Alzheimer’s disease mutations in amyloid protein precursor alter proteolysis by γ-secretase to increase amyloid β-peptides of ≥45 residues

Production of amyloid β-protein (Aβ) is carried out by the membrane-embedded γ-secretase complex. Mutations in the transmembrane domain of amyloid β-protein precursor (APP) associated with early-onset familial Alzheimer's disease (FAD) can alter the ratio of aggregation-prone 42-residue Aβ (Aβ42) to 40-residue Aβ (Aβ40). However, APP substrate is proteolyzed processively by γ-secretase along two pathways: Aβ49→Aβ46→Aβ43→Aβ40 and Aβ48→Aβ45→Aβ42→Aβ38. Effects of FAD mutations on each proteolytic step are unknown, largely due to difficulties in detecting and quantifying longer Aβ peptides. To address this, we carried out systematic and quantitative analyses of all tri- and tetrapeptide coproducts from proteolysis of wild-type and 14 FAD-mutant APP substrates by purified γ-secretase. These small peptides, including FAD-mutant forms, were detected by tandem mass spectrometry and quantified by establishing concentration curves for each of 32 standards. APP intracellular domain (AICD) coproducts were quantified by immunoblot, and the ratio of AICD products corresponding to Aβ48 and Aβ49 was determined by mass spectrometry. Levels of individual Aβ peptides were determined by subtracting levels of peptide coproducts associated with degradation from those associated with production. This method was validated for Aβ40 and Aβ42 by specific ELISAs and production of equimolar levels of Aβ and AICD. Not all mutant substrates led to increased Aβ42/40. However, all 14 disease-causing mutations led to inefficient processing of longer forms of Aβ ≥ 45 residues. In addition, the effects of certain mutations provided insight into the mechanism of processive proteolysis: intermediate Aβ peptides apparently remain bound for subsequent trimming and are not released and reassociated

Global apparent temperature sensitivity of terrestrial carbon turnover modulated by hydrometeorological factors

We are in debt to FLUXNET principal investigators and researchers for the fundamental measurements and synthesis datasets used to build the upscaled and in situ flux datasets used in this study. The work used eddy covariance data from La Thuile Synthesis Dataset, which were provided by the FLUXNET community. In particular, we thank A. Altaf, J. Beringer, P. Blanken, C. Brümmer, S. Burns, J. Cleverly, E. Cremonese, T. Grünwald, P. Kolari, W. Jans, M. Leonardo, T. Manise, M. Mund, A. Noormets, E. Pendall, C. Pio, S. Prober, L. Šigut, A. Varlagin and W. Woodgate, who provided us with site-level measurements of soil carbon and vegetation biomass, and B. Amiro, J. Ardö, S. Arndt, D. Baldocchi, L. Belelli, F. Bosveld, D. Bowling, N. Buchmann, A. Christen, M. Cuntz, A. Desai, B. Drake, I. Goded, A. Goldstein, C. Gough, S. Ivan, L. Hutley, I. Janssens, M. Karan, H. Kobayashi, M. Korkiakoski, B. Kruijt, S. Linder, B. Loubet, I. Mammarella, S. Minerbi, W. Munger, Z. Nagy, D. Papale, A. Richardson, B. Ruiz, E.P. Sanchez-Canete, FCE. Silva, E. Veenendaal, S. Wharton, G. Wohlfahrt, J. Wood, D. Yakir and D. Zona, who provided contacts and/or references for us to find site-level measurements of soil carbon and vegetation biomass. We are thankful to S. Bao and S. Besnard for helping with collected and processed site-level FLUXNET and vegetation biomass data. We thank M. Migliavacca and M. Schrumpf for providing reference and useful resources for data collection. N.F. acknowledges support from the International Max Planck Research School for Global Biogeochemical Cycles. Publisher Copyright: © 2022, The Author(s).The ecosystem carbon turnover time—an emergent ecosystem property that partly determines the feedback between the terrestrial carbon cycle and climate—is strongly controlled by temperature. However, it remains uncertain to what extent hydrometeorological conditions may influence the apparent temperature sensitivity of τ, defined as the factor by which the carbon turnover time increases with a 10 °C rise in temperature (Q10). Here, we investigate the responses of the ecosystem carbon turnover to temperature and hydrometeorological factors using an ensemble of observation-based global datasets and a global compilation of in situ measurements. We find that temperature and hydrometeorology are almost equally important in shaping the spatial pattern of ecosystem carbon turnover, explaining 60 and 40% of the global variability, respectively. Accounting for hydrometeorological effects puts a strong constraint on Q10 values with a substantial reduction in magnitude and uncertainties, leading Q10 to converge to 1.6 ± 0.1 globally. These findings suggest that hydrometeorological conditions modulate the apparent temperature sensitivity of terrestrial carbon turnover times, confounding the role of temperature in quantifying the response of the carbon cycle to climate change.publishersversionpublishe

A review of gallium nitride LEDs for multi-gigabit-per-second visible light data communications

The field of visible light communications (VLC) has gained significant interest over the last decade, in both fibre and free-space embodiments. In fibre systems, the availability of low cost plastic optical fibre (POF) that is compatible with visible data communications has been a key enabler. In free-space applications, the availability of hundreds of THz of the unregulated spectrum makes VLC attractive for wireless communications. This paper provides an overview of the recent developments in VLC systems based on gallium nitride (GaN) light-emitting diodes (LEDs), covering aspects from sources to systems. The state-of-the-art technology enabling bandwidth of GaN LEDs in the range of >400 MHz is explored. Furthermore, advances in key technologies, including advanced modulation, equalisation, and multiplexing that have enabled free-space VLC data rates beyond 10 Gb/s are also outlined

The Impact of Attachment Styles on Social Competence of Adolescent Students

Attachment styles are indispensable elements in evoking human behavior. Precious and priceless social relations or social behavior of every individual is ever more determined by these styles only. Adapting to positive well-being at home, school and peer adjustments are the essential social capabilities expected from the adolescents in order to have effective behavior potentials. Mostly, accomplishments and achievements of academic pursuits of adolescents seem to get initiated by the affectionate bond they receive either from their parents or from their caretakers. Hence, the current study seeks to sketch the probable link between attachment styles on the social competence of the adolescent students. Here, sample consists of 1152 male and 1188 female adolescent students. The Attachment Styles Questionnaire and The Adolescent Social Competence Scale were used to collect relevant data. Suitable statistical analyses were adopted for analyzing the data. The findings showed that the attachment styles seem to persuade the social competence of the adolescent students

Neural Network-Based Joint Spatial and Temporal Equalization for MIMO-VLC System

The limited bandwidth of white light-emitting diode (LED) limits the achievable data rate in a visible light communication (VLC) system. A number of techniques, including multiple-input-multiple-output (MIMO) system, are investigated to increase the data rate. The high-speed optical MIMO system suffers from both spatial and temporal cross talks. The spatial cross-talk is often compensated by the MIMO decoding algorithm, while the temporal cross talk is mitigated using an equalizer. However, the LEDs have a non-linear transfer function and the performance of linear equalizers are limited. In this letter, we propose a joint spatial and temporal equalization using an artificial neural network (ANN) for an MIMO-VLC system. We demonstrate using a practical imaging/non-imaging optical MIMO link that the ANN-based joint equalization outperforms the joint equalization using a traditional decision feedback as ANN is able to compensate the non-linear transfer function as well as cross talk

MIMO Visible Light Communications Using a Wide Field-of-View Fluorescent Concentrator

This letter reports a demonstration of a 2 x 2 multiple-input multiple-output (MIMO) indoor visible-light communication (VLC) system using a novel fluorescent optical concentrator-based receiver. This potentially allows a high degree of spatial multiplexing to be achieved using a simple receiver structure that can have a wide field-of-view. Details of a two-channel MIMO VLC system that operates at 32 Mb/s with a receiver acceptance angle of ±22.5° are given, and future directions are discussed.PostprintPeer reviewe