Wrist worn raw-data accelerometers are used increasingly in large-scale population research. We examined whether sleep parameters can be estimated from these data in the absence of sleep diaries. Our ...heuristic algorithm uses the variance in estimated z-axis angle and makes basic assumptions about sleep interruptions. Detected sleep period time window (SPT-window) was compared against sleep diary in 3752 participants (range = 60-82 years) and polysomnography in sleep clinic patients (N = 28) and in healthy good sleepers (N = 22). The SPT-window derived from the algorithm was 10.9 and 2.9 minutes longer compared with sleep diary in men and women, respectively. Mean C-statistic to detect the SPT-window compared to polysomnography was 0.86 and 0.83 in clinic-based and healthy sleepers, respectively. We demonstrated the accuracy of our algorithm to detect the SPT-window. The value of this algorithm lies in studies such as UK Biobank where a sleep diary was not used.
This paper investigates, theoretically, the temperature dependence of the performance of solar cells in the temperature range 273–523K. The solar cell performance is determined by its parameters, ...viz., short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF) and efficiency (η). Solar cells based on semiconductor materials such as Ge, Si, GaAs, InP, CdTe and CdS are considered here. Reverse saturation current density (Jo) is an important diode parameter which controls the change in performance parameters with temperature. In this work, reverse saturation current density (Jo=C.T3.exp (−qEg/kT)) is determined for three cases. Cases (I) and (II) correspond to C=17.90 and 50mAcm−2K3 respectively, whereas, case (III) corresponds to C.T3=A=1.5×108mAcm−2. The maximum achievable Voc, Jsc, FF and η of solar cells are calculated for AM1.5G and AM0 spectra and are compared with theoretical and experimental results in the literature. Highest Voc, FF and η are achieved for case (III). The performance of cells for case (III) gives the best agreement between the calculated and available theoretical and experimental data for solar cells based on the materials, Si, Ge, GaAs whereas, for InP, CdTe and CdS, case (I) seems to be more appropriate at 298K. Moreover, as temperature changes, cases (I) and (II) are more suitable to describe the performance of solar cells. The rate of change of performance parameters with temperature, viz., dJsc/dT, dVoc/dT, dFF/dT and dη/dT are calculated and compared with the available data in the literature. In addition to theoretical results, the experimentally determined performance parameters of silicon solar cells and their rate of change with temperature are also presented.
► Investigation considers all the potential semiconductor materials for solar cells. ► An analysis of the dependence of temperature on the material properties has been presented. ► Study considers three models that have been reported in the literature. ► Temperature dependence of solar cell performance as function of various materials is explained. ► Analysis concludes with establishing the self consistency in the models.
Climate change is a critical yield–limiting factor that has threatened the entire global crop production system in the present scenario. The use of biostimulants in agriculture has shown tremendous ...potential in combating climate change–induced stresses such as drought, salinity, temperature stress, etc. Biostimulants are organic compounds, microbes, or amalgamation of both that could regulate plant growth behavior through molecular alteration and physiological, biochemical, and anatomical modulations. Their nature is diverse due to the varying composition of bioactive compounds, and they function through various modes of action. To generate a successful biostimulatory action on crops under different parameters, a multi–
omics
approach would be beneficial to identify or predict its outcome comprehensively. The ‘
omics’
approach has greatly helped us to understand the mode of action of biostimulants on plants at cellular levels. Biostimulants acting as a messenger in signal transduction resembling phytohormones and other chemical compounds and their cross–talk in various abiotic stresses help us design future crop management under changing climate, thus, sustaining food security with finite natural resources. This review article elucidates the strategic potential and prospects of biostimulants in mitigating the adverse impacts of harsh environmental conditions on plants.
Due to extensive root system, connected rhizome bamboos are considered suitable for improving soil properties within a short period, though most of the claims are anecdotal and need to be supported ...with quantified data. The study evaluates seven bamboo species viz., Bambusa balcooa, Bambusa bambos, Bambusa vulgaris, Bambusa nutans, Dendrocalamus hamiltonii, Dendrocalamus stocksii and Dendrocalamus strictus for their rooting pattern and impact on soil health properties. Coarse and fine root intensity was maximum in B. vulgaris. Coarse root biomass ranged from 0.6 kg m
in B. nutans to 2.0 kg m
in B. vulgaris and B. bambos. Fine root biomass ranged from 1.1 kg m
in B. nutans to 4.5 kg m
in D. hamiltonii. Contribution of fine roots in terms of intensity and biomass was much higher than coarse roots. Fine root biomass showed declining trend with increase in soil depth in all the species. During sixth year, the litter fall ranged from 8.1 Mg ha
in D. stocksii to 12.4 Mg ha
in D. hamiltonii. Among soil physical properties significant improvement were recorded in hydraulic conductivity, water stable aggregates and mean weight diameter. Soil pH, organic carbon and available phosphorus under different species did not reveal any significant changes, while significant reduction was observed in total nitrogen and potassium. Significant positive correlation was observed between WSA and iron content. Soil microbial population and enzyme activities were higher in control plot. Considering root distribution, biomass, soil hydraulic conductivity and water stable aggregates, B. bambos, B. vulgaris and D. hamiltonii are recommended for rehabilitation of degraded lands prone to soil erosion.
Gamma-ray shielding competence of silicate and borate heavy metal oxide glasses has been investigated using linear attenuation coefficients, effective atomic numbers and exposure buildup factors ...(EBF). The gamma-ray EBF were computed using the Geometric Progression (G-P) fitting method for photon energies from 0.015 to 15MeV, and for penetration depths up to 40 mean free paths (mfps). The macroscopic effective removal cross-section for fast neutron has been calculated for energy range from 2 to 12MeV. It is found that bismuth silicate glass has superior shielding properties and is suitable for replacement of lead glasses. The present investigation is very useful for gamma-ray and neutron shielding and design for lead-free shielding glass in radiological engineering.
•Radiation shielding efficiencies of heavy metal oxide glasses have been investigated.•Silicate glasses, bismuth borate glass and ZBB glasses were discussed.•Lead-free 70 Bi2O3:30 SiO2 is found to be the superior shielding glass.
In a competitive electricity market, an accurate forecasting of energy prices is an important activity for all the market participants either for developing bidding strategies or for making ...investment decisions. An adaptive wavelet neural network (AWNN) is proposed in this paper for short-term price forecasting (STPF) in the electricity markets. A commonly used Mexican hat wavelet has been chosen as the activation function for hidden-layer neurons of feed-forward neural network (FFNN). To demonstrate the effectiveness of the proposed approach, day-ahead prediction of market clearing price (MCP) of Spain market, which is a duopoly market with a dominant player, and locational marginal price (LMP) forecasting in PJM electricity market, are considered. The forecasted results clearly show that AWNN has good prediction properties compared to other forecasting techniques, such as wavelet-ARIMA, multi-layer perceptron (MLP) and radial basis function (RBF) neural networks as well as recently proposed fuzzy neural network (FNN).
Abstract
In this report, the effect of rare-earth (RE
3+
) ion substitution on structural, microstructural, and electrical properties in barium bismuth titanate (BaBi
4
Ti
4
O
15
) (BBTO) Aurivillius ...ceramics has been investigated. The Rietveld refinements on X-ray diffraction (XRD) patterns confirm that all the samples have an orthorhombic crystal system with A2
1
am space group. Meanwhile, temperature dependent synchrotron XRD patterns reveal that the existence of dual phase in higher temperature region. The randomly oriented plate-like grains are experimentally strived to confirm the distinctive feature of bismuth layered Aurivillius ceramics. The broad band dielectric spectroscopic investigation signifies a shifting of ferroelectric phase transition (T
m
) towards low temperature region with a decrease of the RE
3+
-ionic radii in BBTO ceramics. The origin of diffuse ferroelectric phase transitions followed by stabilization of the relaxor ferroelectric nature at high frequency region is explained using suitable standard models. The temperature dependent ac and dc conductivity results indicate the presence of double ionized oxygen vacancies in BBTO ceramics, whereas the dominance of single ionized oxygen vacancies is observed in RE-substituted BBTO ceramics. The room temperature polarization vs. electric field (P–E) hysteresis loops are shown to be well-shaped symmetric for BBTO ceramics, whereas slim asymmetric ferroelectric characteristics developed at RE-substituted BBTO ceramics.
The structural and light emission properties of calcium tungstate (CaWO4) nanoparticles containing Eu3+ and Dy3+ are studied. CaWO4 nanoparticles were prepared by chemical routes followed by drying ...at 80°C, doping with 1, 3, 5, 7 and 10 mol% of Eu2O3 and/or Dy2O3 and final annealing at 800oC. The samples were characterized by field emission-scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), synchrotron X-ray diffraction (XRD), Raman and photoluminescence (PL) spectroscopy. FE-SEM studies show that CaWO4 sample dried at 80°C contains spherical particles of diameter ∼5 μm, and upon annealing at 800°C, dense and irregular shaped structures are formed. EDS mapping found a uniform distribution of Eu and Dy ions and only a small segregation in the CaWO4 matrix is observed. XRD studies revealed the co-existence of the tetragonal CaWO4 and cubic Dy2O3 and/or Eu2O3 phases in the doped samples and rule out the replacement of Ca2+ by rare-earth ions. The structural parameters: crystallite size, lattice strain, unit cell dimensions, atomic position coordinates, bond-lengths, bond-angles and cation-oxygen coordination numbers were determined. The short-range structure of CaWO4 consists of interconnected CaO8 and WO4 units. All the W–O bonds in WO4 units have the same length whereas two types of Ca–O bond-lengths exist in CaO8 units. The undoped CaWO4 sample annealed at 800°C, has the smallest Ca–O bond-lengths and unit cell dimensions due to the compressive macrostrain induced by heat-treatment. On incorporating Eu3+ and Dy3+, the W–O and Ca–O bond-lengths increase slightly. Raman spectra of all the samples are similar and show W–O vibrational modes. PL studies found that the undoped CaWO4, Eu and Dy-doped CaWO4 samples emit blue, red and yellow light respectively. The co-doped sample: 2 mol% Eu2O3–5 mol% Dy2O3–CaWO4 was closest to the ideal white light emission properties.
•Structure-property correlations in Eu2O3/Dy2O3 and CaWO4 composite samples.•Eu and Dy ions expand CaWO4 lattice.•3-Mol% Eu2O3 gives maximum luminescence in CaWO4.•Luminescence intensity decreases with increase in Dy2O3 from 1 to 10 mol%.•Eu and Dy co-doping in CaWO4 produces white light emission.
The transplacental route of vertical transmission of Hepatitis B Virus (HBV) has been known for over a decade. Here we present evidence which suggest HBV can replicate in placenta. Forty-one HBsAg ...positive and 10 control pregnant women were enrolled in the study after obtaining informed consent. HBV positives were further divided in the High Viral Load (HVL) Group and Low Viral Load (LVL) Group according to INASL guidelines 2018. The Presence of the HBV DNA and expression of NTCP in the placenta was analyzed by qPCR/RT-qPCR and/or immunohistochemistry (IHC). The presence of cccDNA was assessed using Digital Droplet PCR while the presence of pre-genomic (pg) RNA was assessed through qRT-PCR and sequencing. The presence of HBeAg and HBcAg in the placenta was assessed by IHC. Immunostaining of NTCP, HBeAg and HBcAg on trophoblasts along with the presence of total HBV DNA, cccDNA and pgRNA indicated, that these cells are not only susceptible to HBV infection but may also support viral replication. This is further supported by the finding that trophoblasts of the several HBeAg seronegative samples harbored the HBeAg. Although, we did not find any correlation in NTCP expression and viral markers with viral load indicates placental replication may not aping hepatocytes. The presence of the HBV receptor, NTCP along with the presence of cccDNA, pgRNA, and HBeAg in placenta of HBV infected females without circulating HBeAg suggest that placenta act as a replication host.
PDF
