To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
The prevalence of dementia is rising in low-resource countries, where specialist memory services are almost non-existent. The COVID-19 pandemic has created opportunities for innovative remote healthcare. Research shows a lack of dementia literacy and help-seeking behaviour for memory-related problems among older adults in South Asian countries. This paper proposes a remote memory service model and virtual dementia training in South Asian countries, called Memory First Aid (MFA). MFA offers help to a person experiencing memory difficulties until appropriate professional help is received. The MFA course is a 12-h webinar-based package consisting of four weekly modules. It covers dementia awareness and clinical features. The aim is to develop a non-medical workforce able to screen and assess older people with suspected dementia.
Field experiments were conducted to standardize protocols for site-specific fertilizer nitrogen (N) management in Bt cotton using Soil Plant Analysis Development (SPAD) chlorophyll meter. Performance of different SPAD-based site-specific N management scenarios was evaluated vis-à-vis blanket fertilizer N recommendation. The N treatments comprised a no-N (control), four fixed-time and fixed N doses (60, 90, 120, and 150 kg N ha-1) including the recommended dose (150 kg ha-1), and eight fixed-time and adjustable N doses based on critical SPAD readings of 45 and 41 at first flowering and boll formation stages, respectively. The results revealed that by applying 45 or 60 kg N ha-1 at thinning stage of the crop and critical SPAD value-guided dose of 45 or 30 kg N ha-1 at first flowering stage resulted in yields similar to that recorded by applying the recommended dose of 150 kg N ha-1. However, significantly higher N use efficiency as well as 30–40% less total fertilizer N use was recorded with site-specific N management. Applying 30 kg N ha-1 at thinning and SPAD meter-guided 45 kg N ha-1 at first flowering were not enough and required additional SPAD meter-guided 45 kg N ha-1 at boll formation for sustaining yield levels equivalent to those observed by following blanket recommendation but resulted in 20% less fertilizer N application. Our data revealed that SPAD meter-based site-specific N management in Bt cotton results in optimum yield with dynamic adjustment of fertilizer N doses at first flowering and boll formation stages. The total amount of N fertilizer following site-specific management strategies was substantially less than the blanket recommendation of 150 kg N ha-1, but the extent may vary in different fields.
In this paper, a high gain wideband circularly polarized (CP) microstrip antenna is presented for broadband operation. The proposed structure comprised of a partially grounded printed monopole antenna loaded with a split ring resonator and a metallic reflector. By using the metallic reflector surface underneath the patch radiator results in the reflected waves in the same phase with main lobe radiation, thereby improving the gain and it also acts like a secondary radiator to generate wideband CP behavior in the proposed design. A gain enhancement of 4.3 dBi is achieved in the operating frequency band as compared with the design without a metallic reflector. The maximum gain achieved in the presented method is 8.6 dBic over the entire operating range. The proposed design shows a wideband behavior ranging from 4.30 to 9.10 GHz with the 10-dB impedance bandwidth of 71.64%. In addition, the proposed design yielded a broadside right hand CP radiation with a 3-dB axial ratio bandwidth of 33.88% from 4.98 to 7.01 GHz. The proposed antenna is fabricated and experimental results on reflection coefficient, gain, axial ratio, and radiation patterns concede well with simulation results.
In this chapter, we shall study the role of institutions in clean energy transitions in developing countries. Renewable energy (RE) for electricity generation has been proposed as a way to bridge the gap between affordable and clean-energy infrastructure. We shall examine the drivers of past and planned solar photovoltaic (PV) electricity-capacity expansion in eight African countries during a period of rapidly falling technology costs. The countries in our sample that experienced RE expansion do not have liberalized market-oriented electricity sectors, and many provide only limited policy support. Careful cross-case comparisons point to a set of financing, political/regulatory, value capture and technical capabilities that may help to explain RE outcomes. Although these findings are specific to the group of African countries we studied, they may hold lessons for other settings in the ‘second wave’ of RE development.
International Ocean Discovery Program Expedition 355 drilled Sites U1456 and U1457 in Laxmi Basin (eastern Arabian Sea) to document the impact of the South Asian monsoon on weathering and erosion of the Himalaya. We revised the chronostratigraphic framework for these sites using a combination of biostratigraphy, magnetostratigraphy and strontium isotope stratigraphy. The sedimentary section at the two sites is similar and we divided it into six units bounded by unconformities or emplaced as a mass-transport deposit (MTD). Unit 1 underlies the MTD, and is of early–middle Miocene age at Site U1456 and early Paleocene age at Site U1457. An unconformity (U1) created by emplacement of the MTD (unit 2) during the late Miocene Epoch (at c. 9.83–9.69 Ma) separates units 1 and 2 and is identified by a marked change in lithology. Unit 3 consists of hemipelagic sediment with thin interbeds of graded sandstone of late Miocene age, separated from unit 4 by a second unconformity (U2) of 0.5–0.9 Myr duration. Unit 4 consists of upper Miocene interbedded mudstone and sandstone and hemipelagic chalk deposited between c. 8 and 6 Ma. A c. 1.4–1.6 Myr hiatus (U3) encompasses the Miocene–Pliocene boundary and separates unit 4 from unit 5. Unit 5 includes upper Pliocene – lower Pleistocene siliciclastic sediment that is separated from unit 6 by a c. 0.45 Myr hiatus (U4) in the lower Pleistocene sediments. Unit 6 includes a thick package of rapidly deposited Pleistocene sand and mud overlain by predominantly hemipelagic sediment deposited since c. 1.2 Ma.
Upper water column dynamics in the eastern Arabian Sea were reconstructed in order to investigate changes in the activity of the South Asian / Indian monsoon during the early Pleistocene (c. 1.5–2.7 Ma). We used planktic foraminiferal assemblage records combined with isotopic (δ18O and δ13C) data, Mg/Ca-based sea surface temperatures and seawater δ18O records to estimate changes in surface water conditions at International Ocean Discovery Program (IODP) Site U1457. Our records indicate two distinct regimes of monsoon-induced changes in upper water structure during the periods c. 1.55–1.65 Ma and c. 1.85–2.7 Ma. We infer that a more stratified upper water column and oligotrophic mixed layer conditions prevailed during the period 1.85–2.7 Ma, which may be due to overall weaker South Asian / Indian winter (NE) and summer (SW) monsoon circulations. The period 1.55–1.65 Ma was characterized by enhanced eutrophication of the mixed layer, which was probably triggered by intensified winter (NE) monsoonal winds. The long-term trend in hydrographic changes during 1.55–1.65 Ma appears to be superimposed by short-term variations, probably reflecting glacial/interglacial changes. We suggest that an intensification of the South Asian / Indian winter monsoon circulation occurred between ∼1.65 Ma and 1.85 Ma, which is most likely due to the development of strong meridional and zonal atmospheric circulations (i.e. Walker Circulation and Hadley Circulation) because of strong equatorial East–West Pacific temperature gradients.
We report Electrically reduced graphene oxide (GO) and n-type Si heterostructure junction-based photovoltaic cell. The transition of the insulating properties of GO to that of semi-conducting was achieved by applying electric voltages using 5, 10, and 15 V biasing. The photovoltaic device I–V characteristics corresponding to the increasing (5–15 V) reduction voltages, obtained on exposure of 25 mW/cm2 visible light, showed approximately same fill factor with increased efficiency. The maximum efficiency of 1.12% was observed under ultraviolet light exposure for photovoltaic cell consisting GO reduced using 15 V reduction voltage. GO was synthesized using the modified Hummers’ technique and characterized by X-ray diffraction (XRD), ultraviolet–visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). The GO characteristic XRD peak corresponding to plane (001) was observed at 9.16°. The UV-Vis spectrum for GO displayed an absorption peak at 228.5 nm, and the corresponding Tauc plot analysis provided a band gap of 4.74 eV. The FTIR analysis showed presence of C=O (1713 cm−1), C=C (1627 cm−1), C–OH (1418 cm−1), C–O–C (1252 cm−1), C–O (1030 cm−1), and C–H (827 cm−1) functional groups in GO.
Sol–gel spin coating is applied to fabricate the pure and different concentrations of aluminum (Al)-doped ZnO films on high-quality silicon substrates. All films are showing high crystallinity in X-ray diffraction study, and lattice constants were obtained using PowderX software. The value of crystallite size was found in range of 20–40 nm. EDX/SEM mapping was performed for 2 wt% Al-doped ZnO film, which shows the presence of Al and its homogeneous distribution in the film. SEM investigation shows nanorods morphology all over the surface of films, and the dimension of nanorods is found to increase with Al doping. The E(g)dire. values were estimate in range of 3.25–3.29 eV for all films. Linear refractive index was found in range of 1.5–2.75. The χ1 value is found in range of 0.13–1.4 for all films. The χ3 values are found in range of 0.0053 × 10−10 to 6.24 × 10−10 esu for pure and doped films. The n2 values were also estimated. These studies clearly showed that the properties of ZnO have been enriched by Al doping, and hence doped films are more appropriate for optoelectronic applications.
Herein, we report the detailed optoelectronic characteristics of low cost fabricated pristine and 1, 5, 10, and 15 wt% Mg-doped ZnO films on the FTO substrate (MZO/FTO) through the spin coating technique. High crystallinity and single phase of the film were confirmed by X-ray diffraction investigation. The average crystallite size was in the range of 46–78 nm. Homogeneous distribution of Mg doping in ZnO was approved by elemental mapping analysis. The fiber-like surface morphology was confirmed by the scanning electron microscopy analysis. Optical transparency was observed in the range of 40–80% for the fabricated films. The optical band gaps for direct and indirect transitions obtained from Tauc’s relation are in the range of 3.103–3.283 eV and 2.423–2.968 eV, respectively. It is also observed that the energy gap of MZO films decreases with an increase in Mg doping from 1 to 15%. The respective stable values of absorption and refractive indices are obtained in the range of ∼0.036–0.088 and ∼1.71–2.1. The linear and nonlinear optical susceptibilities as well as the nonlinear refractive index values were calculated. Additionally, Z-scan measurement was carried out at 532 nm wavelength. The nonlinear absorption coefficient and the imaginary part of third-order nonlinear susceptibility were estimated and corresponding values are obtained in the range of 0.35–123 (×10−5) cm/W and 0.084–29.7 (×10−8) e.s.u., respectively. Moreover, the optical limiting threshold values were obtained in the range of 2.57–6.34 kJ/cm2. The MZO/FTO films are showing strong optical limiting behavior compared to pristine. The output results suggest that MZO films are better contenders for optoelectronic applications.
This paper describes the spatial and temporal investigation of laser ablated plasma plume of cerium oxide target using Langmuir probe. Cerium oxide target was ablated using a KrF (λ ~ 248 nm) gas laser. Experimental studies confirmed that oxygen partial pressure of 2 × 10−2 mbar is sufficient enough to get good quality films of cerium oxide. At this pressure, plume was diagnosed for their spatial and temporal behavior. Spatial distribution was investigated at a distance of 15 mm, 30 mm, and up to a maximum distance of 45 mm from the target, whereas temporal behavior has been recorded in the range of 0 to 50 µS with an interval of 0.5 µS. The average electron densities are found to be maximum at 30 mm from the target position and the plasma current of the laser ablated ceria is found to be maximum at 22 µS.
Cyanobacteria represent promising organic inputs in rice–wheat cropping system, as they contribute towards accretion of N and C, besides secreting growth-promoting substances which influence plant productivity and soil fertility. The present study focused towards using a combinatorial approach for evaluating field-level colonization of cyanobacteria in soil and their effect on soil microbiological and plant parameters, employing agronomic and molecular tools. A consortium of cyanobacterial strains (BF1, Anabaena sp., BF2, Nostoc sp., BF3, Nostoc sp. and BF4, Anabaena sp.) was employed in different three-and four-member combinations along with 75% N + Full dose of P and K fertilizers. A significant enhancement in microbial activity and plant growth/yields and savings of 25% N in the wheat–rice cropping sequence were recorded, especially in treatments involving 75% N + Full dose of PK+BF1+BF2+BF4 and T5, i.e. 75% N + Full dose of PK+BF1+BF2+BF3. Such treatments were significantly higher or statistically at par with fertilizer controls – 75% N + Full dose of PK fertilizers. The use of DNA-based markers further helped to establish the colonization of the inoculated cyanobacteria, especially BF2 and BF3 strains. Our study clearly illustrated the establishment of inoculated cyanobacterial strains and their role in enhancing the crop productivity and soil health of the rice–wheat cropping system.
A total of 54 horsegram landraces collected from three altitudinal zones (lower hills, mid hills and higher hills) of Himalayan region were characterized and evaluated for nine quantitative characters. Accessions collected from lower and higher hills were more diverse and differed significantly from mid hills accessions for characters viz., days to flowering, days to physiological maturity, plant height and grain yield per plant. The plotting of first and second principal component axes scores revealed that there was dispersion among the accessions collected from different altitudinal groups. It reveals a less variability among the landraces collected from same altitudinal group but high variability among the landraces collected from different altitudes. This suggests that the horsegram landraces are adapted to specific zone due to different selection pressure practiced by the farmers at different altitudes. Farmers in lower and higher hills select the landraces having high grain yield coupled with less reproductive phase duration and taller in nature.
Insect pests cause major damage to stored grain and foodstuffs, reducing the products' weight, quality and market value. Eight spices commonly used to add flavour and colour to food were evaluated, singly and in combination, for their contact and fumigant toxicity, repellency and effects on progeny development against the cowpea weevil Callosobruchus maculatus F. and rust red flour beetle Tribolium castaneum Herbst. The powders of large cardamom, turmeric and ginger showed contact toxicity against the two test insects. Green cardamom powder was found to have fumigant toxicity against adults of both insects. Clove powder at 1.5 g/50 g dose showed 100% repellency against adults of T. castaneum. The powders of large cardamom, cinnamon and clove caused complete inhibition of progeny production in C. maculatus and T. castaneum at a dose of 5 g/100 g. A 1:1 mixture of green cardamom and turmeric showed both contact and fumigant toxicity against C. maculatus, while a mixture of clove and large cardamom showed repellency and inhibited progeny development in T. castaneum.
We report the fabrication and characterization of segmented element power generator modules of 254 thermoelectric elements. The element is 1 mm × 1 mm in area, which consists of 300 μm thickness Bi2Te3 and 50 μm thickness ErAs:(InGaAs)1-x(InAlAs)x, so that each segment can work at different temperature ranges. Erbium arsenide metallic nanoparticles are incorporated to create scattering centers for middle and long wavelength phonons, provide charge carriers, and form local Schottky barriers for electron filtering. The thermoelectric properties of ErAs:InGaAlAs were characterized by variable temperature measurements of thermal conductivity, electrical conductivity and Seebeck coefficient from 300 K to 600 K. Generator modules of Bi2Te3 and ErAs:InGaAlAs segmented elements were fabricated and an output power over 5.5 W was measured. The performance of the thermoelectric generator modules can further be improved by improving the thermoelectric properties of the element material, and reducing the electrical and thermal parasitic losses.
We report the fabrication and characterization of thin film power generators composed 400 p- and n-type ErAs:InGaAs/InGaAlAs superlattice thermoelectric elements. The thermoelectric elements incorporate erbium arsenide metallic nanoparticles into the semiconductor superlattice structure to provide charge carriers and create scattering centers for phonons. 10 µm p- and n-type InGaAs/InGaAlAs superlattices with embedded ErAs nano-particles were grown on InP substrates using molecular beam epitaxy. Thermal conductivity values were measured using the 3ω method and cross-plane Seebeck coefficients were determined using Seebeck device test patterns. 400 element ErAs:InGaAs/InGaAlAs thin film power generators were fabricated from superlattice elements 10 µm thick and 200 µm × 200 µm in area. The output power was 4.7 milliwatts for an external electrical load resistor of 150 Ω at about 80 K temperature difference drop across the generator. We discuss the limitations to the generator's performance and provide suggestions for further improvement.
A solid solution of lead magnesium niobate (PMN), a relaxor ferroelectric, with lead zirconate (PZ), an antiferroelectric, gives rise to a system that behaves like a relaxor ferroelectric for lower concentrations of PZ, and like a normal ferroelectric above 50% substitution by PZ. This paper reports the heat-capacity behavior of (1 – x)PMN–xPZ for the composition range x = 0.30 to 0.95 and temperature range 300–600 K. It was observed that, although the atomic structure of the material is basically crystalline throughout, with sharp x-ray diffraction peaks, the crossover from normal–ferroelectric behavior to relaxor–ferroelectric behavior (on decreasing x) is accompanied by a matching crossover from crystalline behavior to glassy behavior, as exhibited in the heat-capacity plots. In other words, the heat-capacity curves for the relaxor compositions bear resemblance to those observed for canonical or conventional glasses, with the glass-transition temperature and the continuous step in specific heat changing gradually as a function of the composition parameter x. However, not all properties match those for canonical glasses. For example, soaking for 24 h at a temperature or 10 to 20 K below the mean glass-transition temperature does not raise the specific heat to a value nearly equal to the value in the unfrozen state. Similarly, the glass-transition temperature (for 0.7PMN–0.3PZ) increases, though only marginally (from 337 K to 343 K), when the rate of heating across the transition is increased by a factor of 50 (from 0.1 K per minute to 5 K per min.). Further, the temperature interval ΔT over which most of the glass transition occurs in the relaxor ferroelectric is typically as large as 30–40 K, compared to only about 10 K for canonical glasses.
Self-enucleation is a rare and disturbing form of self-mutilation. A case is reported in which a schizophrenic patient simultaneously attempted the three main forms of major self-mutilation, that is self-enucleation, amputation of the penis and of the right hand. The historical background, underlying psychiatric factors and possible complications are discussed.
Low temperature processing is necessary for the fabrication of thin-film transistors for electronics-on-glass applications, including active matrix flat-panel displays. One method to achieve this involves the use of pulsed excimer-laser annealing of an Amorphous silicon layer on top of an SiO2 layer. The intense UV laser is absorbed in the Amorphous silicon region, Maintaining a low average temperature. The thickness of the underlying SiO2 layer affects the solidification velocity and hence the grain size of the annealed layer. Previous work has concluded that the resultant grain size is small (<100 nm) and further work is needed in finding ways of increasing grain size. This paper describes how grain size is affected by varying the thickness of the SiO2 layer. Correlations will be discussed.between the solidification velocities and grain size as affected by the varying thickness of the SiO2 layer. The paper includes a comparison between experimental and theoretical results, using equations based on energy balance considerations.
Email your librarian or administrator to recommend adding this to your organisation's collection.