Field studies were conducted in 2021 in Kibler and Augusta, AR, to determine the effect of winter cover crops and cultivar selection on weed suppression and sweetpotato [Ipomoea batatas (L.) Lam.] yield. The split-split-plot studies evaluated three cover crops [cereal rye (Secale cereale L.) + crimson clover (Trifolium incarnatum L.)], [winter wheat (Triticum aestivum L.) + crimson clover], and fallow; weeding (with or without); and four sweetpotato cultivars (‘Heartogold’, ‘Bayou-Belle-6’, ‘Beauregard-14’, and ‘Orleans’). Heartogold had the tallest canopy, while Beauregard-14 and Bayou Belle-6 had the longest vines at 5 and 8 wk after sweetpotato transplanting. Sweetpotato canopy was about 20% taller in weedy plots compared with the hand-weeded treatment, and vines were shorter under weed interference. Canopy height and vine length of sweetpotato cultivars were not related to weed biomass suppression. However, vine length was positively correlated to all yield grades (r > 0.5). Weed biomass decreased 1-fold in plots with cover crops compared with bare soil at Augusta. Cover crop biomass was positively correlated with jumbo (r = 0.29), no. 1 (r = 0.33), and total sweetpotato yield (r = 0.34). Jumbo yield was affected the most by weed pressure. On average, sweetpotato total yield was reduced by 80% and 60% with weed interference in Augusta and Kibler, respectively. Bayou Belle-6 was the high-yielding cultivar without weed interference in both locations. Bayou Belle-6 and Heartogold were less affected by weed interference than Beauregard-14 and Orleans.

The focus of this paper is a numerical simulation study of the flow dynamics in a periodic porous medium to analyse the physics of a symmetry-breaking phenomenon, which causes a deviation in the direction of the macroscale flow from that of the applied pressure gradient. The phenomenon is prominent in the range of porosity from 0.43 to 0.72 for circular solid obstacles. It is the result of the flow instabilities formed when the surface forces on the solid obstacles compete with the inertial force of the fluid flow in the turbulent regime. We report the origin and mechanism of the symmetry-breaking phenomenon in periodic porous media. Large-eddy simulation (LES) is used to simulate turbulent flow in a homogeneous porous medium consisting of a periodic, square lattice arrangement of cylindrical solid obstacles. Direct numerical simulation is used to simulate the transient stages during symmetry breakdown and also to validate the LES method. Quantitative and qualitative observations are made from the following approaches: (1) macroscale momentum budget and (2) two- and three-dimensional flow visualization. The phenomenon draws its roots from the amplification of a flow instability that emerges from the vortex shedding process. The symmetry-breaking phenomenon is a pitchfork bifurcation that can exhibit multiple modes depending on the local vortex shedding process. The phenomenon is observed to be sensitive to the porosity, solid obstacle shape and Reynolds number. It is a source of macroscale turbulence anisotropy in porous media for symmetric solid-obstacle geometries. In the macroscale, the principal axis of the Reynolds stress tensor is not aligned with any of the geometric axes of symmetry, nor with the direction of flow. Thus, symmetry breaking in porous media involves unresolved flow physics that should be taken into consideration while modelling flow inhomogeneity in the macroscale.

Investment in family planning (FP) provides returns through a lifetime. Global evidence shows that FP is the second-best buy in terms of return on investment after liberalizing trade. In this study, we estimate the cumulative benefits of FP investments for India from 1991 to 2016 and project them up to 2061 with four scenarios of fertility levels. The findings suggest that India will have greater elasticity of FP investments to lifetime economic returns compared to the world average (cost–revenue ratio of 1:120). We have taken four scenarios for the goalpost, viz., 2.1, 1.8, 1.6, and 1.4. Although different scenarios of total fertility rate (TFR) levels at the goalpost (i.e., the year 2061) offer varied lifetime returns from FP, scenario TFR < 1.8 will be counterproductive and will reduce the potential benefits. With a comprehensive approach, if the country focuses more on improving the quality of FP services and on reducing the unmet need for FP to enhance reproductive health care and expand maximum opportunities for education and employment for both women and men, it can improve its potential to reap more benefits.

We use well resolved numerical simulations with the lattice Boltzmann method to study Rayleigh–Bénard convection in cells with a fractal boundary in two dimensions for $Pr = 1$ and $Ra \in \left [10^7, 10^{10}\right ]$, where Pr and Ra are the Prandtl and Rayleigh numbers. The fractal boundaries are functions characterized by power spectral densities $S(k)$ that decay with wavenumber, $k$, as $S(k) \sim k^{p}$ ($p < 0$). The degree of roughness is quantified by the exponent $p$ with $p < -3$ for smooth (differentiable) surfaces and $-3 \le p < -1$ for rough surfaces with Hausdorff dimension $D_f=\frac {1}{2}(p+5)$. By computing the exponent $\beta$ using power law fits of $Nu \sim Ra^{\beta }$, where $Nu$ is the Nusselt number, we find that the heat transport scaling increases with roughness through the top two decades of $Ra \in \left [10^8, 10^{10}\right ]$. For $p$ $= -3.0$, $-2.0$ and $-1.5$ we find $\beta = 0.288 \pm 0.005, 0.329 \pm 0.006$ and $0.352 \pm 0.011$, respectively. We also find that the Reynolds number, $Re$, scales as $Re \sim Ra^{\xi }$, where $\xi \approx 0.57$ over $Ra \in \left [10^7, 10^{10}\right ]$, for all $p$ used in the study. For a given value of $p$, the averaged $Nu$ and $Re$ are insensitive to the specific realization of the roughness.

We investigated the occurrence and status of the leaf folder Cnaphalocrocis ruralis (Walker) (Lepidoptera: Crambidae) in accessions of Erianthus spp. maintained as a part of the world germplasm collection at the Research Center of ICAR-Sugarcane Breeding Institute, Kannur, Kerala State, India. The nature, pattern, extent and year-to-year variation in damage were examined and accessions categorized based on relative incidence. The larvae of C. ruralis caused characteristic injury by feeding on chlorophyll bearing tissues leading to the formation of white and transparent streaks on the leaf blade. The grown-up larvae folded the leaf longitudinally with the adaxial surface inside the fold and exposing the abaxial surface, the edges being held in place by bands of silk thread at regular intervals. The length of leaf folds varied from 2.6 to 27.0 cm with a mean of 9.1 cm, which roughly constituted 7.3% of the mean length of the leaf blade. Leaf length, leaf width and leaf area were not correlated with either the leaf fold length or the number of webs. However, the leaf fold length was positively correlated with the number of webs. Attack rates (infestation rate) on cane basis (up to 69.0%) were generally higher than the damage rates (intensity) on leaf basis (up to 50.0%); infestation index ranged between 0.0 and 13.7%. Correlations between infestation rate and intensity varied among the three study years. Non-parametric analysis indicated significant differences among the three years for percent of infested canes and infestation index but not percent of damaged leaves. All accessions showed C. ruralis incidence in at least one experimental year, indicating that none of the accessions tested was immune to its attack. When all 74 accessions were considered on the basis of infestation index, 85.1% were placed in low and moderate categories and only 14.9% in high incidence category. Within the accessions of Erianthus spp., leaf area was not related to infestation rate of cane or damage rate of leaves but positively related to infestation index. The dynamics of the leaf folder in the predominantly paddy ecosystem were discussed in the light of its first occurrence in Erianthus spp. accessions in India and the world.

Setaria cervi, a bovine filarial parasite contains significant acid phosphatase (AcP) activity in its various life stages. Two forms of AcP were separated from somatic extract of adult female parasite using cation exchange, gel filtration and concavalin affinity chromatography. One form having a molecular mass of 79 kDa was characterized as dual specific protein tyrosine phosphatase (ScDSP) based on substrate specificity and inhibition studies. With various substrates tested, it showed significant activity in the order of phospho-L-tyrosine>pNPP>ADP>phospho-L-serine. Inhibition by orthovanadate, fluoride, molybdate, and zinc ions further confirms protein tyrosine phosphatase nature of the enzyme. Km and Vmax determined with various substrates were found to be 16·66 mM, 25·0 μM/ml/min with pNPP; 20·0 mM, 40·0 μM/ml/min with phospho-L-tyrosine and 27·0 mM, 25·0 μM/ml/min with phospho-L-serine. KI with pNPP and sodium orthovanadate (IC50 33·0 μM) was calculated to be 50·0 mM. Inhibition with pHMB, silver nitrate, DEPC and EDAC suggested the presence of cysteine, histidine and carboxylate residues at its active site. Cross-reactivity with W. bancrofti-infected sera was demonstrated by Western blotting. ScDSP showed elevated levels of IgE in chronic filarial sera using ELISA. Under in vitro conditions, ScDSP resulted in increased effector function of human eosinophils when stimulated by IgG, which showed a further decrease with increasing enzyme concentration. Results presented here suggest that S. cervi DSP should be further studied to determine its role in pathogenesis and the persistence of filarial parasite.

Magnetic refrigeration based on the magnetocaloric effect (MCE) has been proposed as an attractive alternative to gas compression technology. Some calculations suggest that MCE can be obtained with higher efficiencies than compressor driven refrigeration. We examine the MCE in a system of nickel ferrite nanoparticles with size range of 6 to 15 nm. A peak in the MCE at 55 K is observed that increases with higher magnetic fields. This gives this system a relatively high peak entropy change compared to other ferrite systems. A sensitive radio-frequency (RF) transverse susceptibility measurement has also been used to study the magnetic anisotropy. We show that the MCE peak is not associated with the blocking temperature and is likely a field-driven surface spin reorientation which also has a signature in the transverse susceptibility. Work supported by NSF-CTS-0408933 and ARO- W911NF-05-1-0354

Sintering studies on Y–Ba–Cu oxide (YBCO)–Agx (x = 0, 0.6, and 1.0 mol) powder were carried out in argon atmosphere to understand the role of silver addition on the densification behavior of these materials. The increase of sintered densities of the compacts with silver addition in argon atmosphere contradicted our earlier observation on sintering of YBCO–Agx powder compacts in air, where the densities decreased for x > 0.6. Thermogravimetric (TG) studies under argon atmosphere indicate a continuous decrease of mass on heating suggesting an enhanced rate of oxygen removal from the YBCO matrix that facilitated the sintering in argon atmosphere. Sintering studies of YBCO–Agx powder compacts in argon in conjunction with earlier observations in air has substantiated our claim that high-temperature oxygen desorption by the silver from the YBCO matrix to the sintering atmosphere controls the rate of densification for these superconducting composites. However, the apparent activation energies for sintering suggest that the sintering process is controlled by yttrium ion diffusion along bulk and grain boundaries.

The association between the different scales of convection on the solar photosphere and the field strengths/flux content of discrete magnetic flux concentrations is analyzed using simultaneously recorded SOHO/MDI high resolution filtergrams and magnetograms. The convective flow field is derived using the Local Correlation Tracking (LCT) technique. The locations and strengths of the flux elements with respect to the flow cells are analyzed to obtain information about different scales of convection.

Laboratory parasitisation rates of a native (Indian) and an exotic (Indonesian) population of the gregarious larval endoparasitoid Cotesia flavipes Cameron (Hymenoptera: Braconidae), mass reared by the group-exposure method in glass chimneys, were examined during 1990–1994 on three hosts, namely the sugarcane shoot borer Chilo infuscatellus Snellen, sugarcane internode borer Chilo sacchariphagus indicus (Kapur) and spotted stemborer Chilo partellus (Swinhoe) (Lepidoptera: Crambidae). Parasitisation rates of both the Indian and Indonesian populations in individual rearing batches showed considerable variation. Correlation and multiple regression analysis of parasitisation rates in rearing batches and three rearing parameters, viz. percent males, number of larvae and number of larvae per female parasitoid, indicated variable influence of the rearing parameters. Parasitisation rates of the Indian population were positively related to percent males and negatively related to number of larvae and number of larvae per female parasitoid in some hosts. The parasitisation rates of the Indonesian population were negatively related to percent males only in Ch. partellus. Mean monthly parasitisation rates of both populations during the study period fluctuated considerably in different hosts. The role of rearing parameters as well as rearing history of host and parasitoid cultures in parasitisation rates is discussed.

Field experiments were carried out at Coimbatore, Tamil Nadu State, India, for four consecutive years (1990–94), to monitor the seasonal activity of Cotesia flavipes Cameron (Hymenoptera: Braconidae), a larval parasitoid of gramineous borers, including the sugarcane shoot borer (Chilo infuscatellus Snellen), sugarcane internode borer (Chilo sacchariphagus indiens (Kapur) and sorghum stemborer (Chilo partellus Swinhoe) (all Lepidoptera: Crambidae). The highest levels of parasitism (0.0–17.9%) were recorded on Ch. partellus followed by Ch. sacchariphagus indiens (0.0–8.3%) and Ch. infuscatelliis (0.0–1.1%). The parasitoid was collected in Ch. partellus and Ch. sacchariphagus indiens in all the four study years, whereas it was not observed in Ch. infuscatelliis during 1993–94. Parasitism rates in Ch. partellus were positively correlated with minimum temperature and afternoon RH. In Ch. sacchariphagus indiens, parasitism levels showed significant negative correlation with minimum temperature. Parasitism rates in Ch. saccharipliagus indidus larvae collected during harvest from seven sugar factory areas of Tamil Nadu State were lower in 1992–93 (0.0–1.8%) and higher in 1993–94 (0.0–3.2%) than those recorded at Coimbatore in the corresponding period (December-March). Cotesia flavipes was the only larval parasitoid recorded from the borers both at Coimbatore and the seven sugar factory areas surveyed in Tamil Nadu.

A sensitive tunnel diode oscillator (TDO) technique operating at 4MHz is used to probe the dynamic response of La 1−x SrxMnO 3 single crystals for x = 0.125, 0.175, 0.28 and 0.33 doping. Systematics of the measured change in reactance (δX) as a function of temperature (30K < T < 320K) and DC magnetic field (0 < H < 6kOe) reveal distinct temperature and field scales associated with the dynamic response of spin. It is notable that these features are far more striking than the corresponding features in static measurements. The results are discussed in the context of structural changes leading to polaron ordering.

Due to the prohibitively high 4.1% lattice mismatch, direct growth of GaAs on Si invariably leads to very high dislocation densities (> 108/cm2) which have precluded its use in device applications despite numerous attempts. However, the growth of low threading dislocation density (∼2 × 106/cm2) relaxed graded Ge/GexSi1−x/Si heterostructures can bridge the gap between lattice constants by replacing the high mismatch GaAs/Si interface with a low mismatch (< 0.1%) GaAs/Ge interface. Although the lattice mismatch problem is thus eliminated, the heterovalent GaAs/Ge interface remains highly susceptible to antiphase disorder. Since antiphase boundaries (APBs) nucleated at the GaAs/Ge interface act as scattering and nonradiative recombination centers, growth of device quality GaAs on Ge/GexSi1−x/Si demands effective suppression of antiphase disorder. The current work investigates the sublattice location of GaAs on 6° offcut (001) Ge/GexSi1−x/Si substrates as a function of atmospheric pressure metal-organic chemical vapor deposition (MOCVD) growth initiation parameters. Two distinct GaAs phases are observed, one dominant at temperatures > 600°C and another at temperatures <500°C. Incomplete phase transitions during pre-growth thermal cycling account for the appearance of localized bands of anti-phase disorder where the polarity of the GaAs film switches. We suspect that background arsenic levels in the MOCVD system are largely responsible for inducing the observed phase transitions. The complete suppression of antiphase disorder under optimized growth conditions is demonstrated by transmission electron microscopy (TEM)

The radio frequency (RF) response of La1-xSrxMnO3 single crystals reveal a variety of features associated with the structural, electronic and magnetic properties of the system. The resonance technique operating at ∼ 4 MHz employed in this study is sensitive to small changes in both the magnetic susceptibility and resistivity of the samples. Very sharp changes in frequency are observed at the ferromagnetic (FM) and structural phase transitions in both the metallic (x = 0.175) and insulating (0.125) crystals studied.

In addition to the known transitions identified as FM and orthorhombic distortions, our experiments show rich structures which are not observed in conventional DC magnetization and transport experiments. Our results demonstrate that RF experiments are ideally suited to investigate the complex phase diagram in the manganites.

The colossal frequency change that we observe at the FM transition in the La1-xSrxMnO3 crystals is indicative of the enormous potential for using these materials in high frequency switching applications.

Relaxed graded Si-Ge/Si layers can be used in a variety of micro-electronics applications such as templates for III-V/Si integration, in high speed field effect transistor (FET) structures and as detectors in optical communication. Each of these applications requires a different final Ge concentration in the graded Si-Ge layer. With increasing Ge content in the graded layer, some of the materials concerns that need to be addressed are- (i) a high surface roughness, (ii) the formation of dislocation pile-ups, and (iii) an increase in the threading dislocation density. We have shown that there is a substantial improvement in the surface roughness and the dislocation pile-up density of the graded Si-Ge layers by depositing on (001) 6° off-cut substrates. The substrate miscut also facilitates favorable intersections of {111} planes that aid reactions between the 60° dislocations to form edge dislocations with Burgers vectors of the type 1/2<110> and <100> resulting in a novel hexagonal dislocation structure. Such reactions occurred more readily in the Ge-rich regions of the graded layers where the growth temperature was high enough to aid dislocation climb. The edge dislocations with in-plane Burgers vectors lack a tilt component and the decreased rate of tilting in the Ge-rich regions is confirmed by triple crystal X-ray reciprocal space maps. This novel dislocation structure offers opportunities to explore new processes which may eliminate spatially variant strain fields in relaxed epitaxial layers.

Electronic defects were introduced at and around the Si-SiO2 interface by exposing thermally-oxidized silicon samples to a 16 keV Si ion beam in an ion implanter. The oxide thickness was 350 Å. Following Si self-implantation, hydrogenation was carried out at room temperature by a 400 eV hydrogen ion beam from a Kaufman source. Experimental results obtained from the admittance-voltage-frequency measurements of the metal-oxide-silicon structures indicated significant passivation of the ion-beam-induced defects.

We have investigated oxygen ion implantation at substoichiometric doses for bandgap modification in silicon. Redistribution of the oxygen atoms during the high temperature anneal results in sharp interfaces aiding the formation of a heterojunction. A most interesting observation is the presence of donors in the vicinity of the implanted region, resulting in extensive counterdoping. Mesa type diodes on the implanted sample exhibit excellent rectification with a diode ideality factor n of 1.2 and a reverse saturation current density of 1 × 10−8 A/cm 2. The near surface region is shown to be crucial for achieving the high rectification behavior.

High-energy hydrogen ion (proton) implantation is used in Si for creating defects, while low-energy H is known for passivation of a variety of defects and impurities. We have carried out a study of low-energy (<0.4 keV) H passivation of defects produced by 100 keV H implantation. Both Schottky barrier transport and deep level transient spectroscopy measurements give evidence for self-passivation of defects produced by H.

In this paper we make an attempt to explain the critical phenomena in ℝ2. We do this by exhibiting a class of functions having growth and for which

do not admit a solution when R is sufficiently small, where B(R) denotes the ball of radius R in ℝ2.