This paper follows a recent article of Nambiar et al. (J. Fluid Mech., vol. 812, 2017, pp. 41–64) on the linear rheological response of a dilute bacterial suspension (e.g. E. coli) to impulsive starting and stopping of simple shear flow. Here, we analyse the time dependent nonlinear rheology for a pair of linear flows – simple shear (a canonical weak flow) and uniaxial extension (a canonical strong flow), again in response to impulsive initiation and cessation. The rheology is governed by the bacterium orientation distribution which satisfies a kinetic equation that includes rotation by the imposed flow, and relaxation to isotropy via rotary diffusion and tumbling. The relevant dimensionless parameters are the Péclet number $Pe\equiv \dot{\unicode[STIX]{x1D6FE}}\unicode[STIX]{x1D70F}$ , which dictates the importance of flow-induced orientation anisotropy, and $\unicode[STIX]{x1D70F}D_{r}$ , which quantifies the relative importance of the two intrinsic orientation decorrelation mechanisms (tumbling and rotary diffusion). Here, $\unicode[STIX]{x1D70F}$ is the mean run duration of a bacterium that exhibits a run-and-tumble dynamics, $D_{r}$ is the intrinsic rotary diffusivity of the bacterium and $\dot{\unicode[STIX]{x1D6FE}}$ is the characteristic magnitude of the imposed velocity gradient. The solution of the kinetic equation is obtained numerically using a spectral Galerkin method, that yields the rheological properties (the shear viscosity, the first and second normal stress differences for simple shear, and the extensional viscosity for uniaxial extension) over the entire range of $Pe$ . For simple shear, we find that the stress relaxation predicted by our analysis at small $Pe$ is in good agreement with the experimental observations of Lopez et al. (Phys. Rev. Lett., vol. 115, 2015, 028301). However, the analysis at large $Pe$ yields relaxations that are qualitatively different. Upon step initiation of shear, the rheological response in the experiments corresponds to a transition from a nearly isotropic suspension of active swimmers at small $Pe$ , to an apparently (nearly) isotropic suspension of passive rods at large $Pe$ . In contrast, the computations yield the expected transition to a nearly flow-aligned suspension of passive rigid rods at high $Pe$ . We probe this active–passive transition systematically, complementing the numerical solution with analytical solutions obtained from perturbation expansions about appropriate base states. Our study suggests courses for future experimental and analytical studies that will help understand relaxation phenomena in active suspensions.

For the first time, we report the identification of NUV bright red clump (RC) stars and the extension of RC stars over two magnitudes both in color and magnitude axis in NUV vs (NUV – optical) color magnitude diagram. We find that the extension of RC is not due to photometric uncertainties. We suggest that the extension could be an effect of field star contamination. We also suggest that if it is an intrinsic property of the cluster then age and/or metallicity spread within the cluster could be the possible reasons for extended RC.

It is no longer possible nor desirable to address the dual challenges of equity and sustainability separately. Instead, they require new thinking and approaches which recognize their interlinkages, as well as the multiple perspectives and dimensions involved. We illustrate how equity and sustainability are intertwined, and how a complex social–ecological systems lens brings together advances from across the social and natural sciences to show how (in)equity and (un)sustainability are produced by the interactions and dynamics of coupled social–ecological systems. This should help understand which possible pathways could lead to sustainable and fair futures.

Onion thrips, Thrips tabaci (Lindeman), is a prominent species infesting onion and tomato in the northern highlands of Tanzania. It causes considerable leaf damage by direct feeding and also transmits the Iris yellow spot virus (IYSV). Hence, one of the objectives of this study was to identify the most resistant onion entries against T. tabaci. One highly resistant (VI038552) and two resistant onion entries (VI038512 and AVON 1067) were identified against T. tabaci. Besides thrips resistance, the bulb size of VI038512 was also equivalent to one of the commercial varieties, Texas. The highly resistant VI038552 recorded the highest yield, followed by the resistant entry, VI038512. However, the yield of AVON 1067 was significantly lower. Elucidation of the biophysical bases of resistance revealed that there was a significant negative correlation between leaf angle as well as leaf toughness and thrips damage. The total epicuticular wax content in the leaves had a weak and non-significant negative relationship with thrips damage. The scanning electron microscopic study confirmed that the wax crystals occurred as filaments, rods, platelets, tubes and complex dendritic structures, and that they were densely arranged in resistant or moderately resistant entries. Studies on the biochemical basis of resistance confirmed that there was a significant negative relationship between total phenol content and thrips damage. Similarly, the relationship between total foliar amino acids or total sugars and thrips damage was inversely correlated and non-significant. Hence, entries VI038552 and VI038512 could be promising candidates for breeding programmes aimed at developing onion varieties that are resistant to thrips and that are high yielding, which will help to enhance the productivity of onions in sub-Saharan Africa.

Essentially all biological processes are highly dependent on the nanoscale architecture of the cellular components where these processes take place. Statistical measures, such as the autocorrelation function (ACF) of the three-dimensional (3D) mass–density distribution, are widely used to characterize cellular nanostructure. However, conventional methods of reconstruction of the deterministic 3D mass–density distribution, from which these statistical measures can be calculated, have been inadequate for thick biological structures, such as whole cells, due to the conflict between the need for nanoscale resolution and its inverse relationship with thickness after conventional tomographic reconstruction. To tackle the problem, we have developed a robust method to calculate the ACF of the 3D mass–density distribution without tomography. Assuming the biological mass distribution is isotropic, our method allows for accurate statistical characterization of the 3D mass–density distribution by ACF with two data sets: a single projection image by scanning transmission electron microscopy and a thickness map by atomic force microscopy. Here we present validation of the ACF reconstruction algorithm, as well as its application to calculate the statistics of the 3D distribution of mass–density in a region containing the nucleus of an entire mammalian cell. This method may provide important insights into architectural changes that accompany cellular processes.

Western flower thrips (WFT) (Frankliniella occidentalis) is an introduced pest that harms French bean production in Kenya and other countries. Since new WFT management approaches are being developed, a closer look at the genetic makeup of WFT populations can give new insights into source habitats, crop colonization patterns or host plant preferences, which are prerequisites for integrated pest management (IPM) strategies. For this purpose, we used six microsatellite loci to analyse the genetic structure, diversity and gene flow of WFT sampled on French beans, intercrops and weeds in Kenyan French bean production areas. The results of this preliminary study indicate that the available microsatellites are sufficiently polymorphic for more detailed analyses on local dispersal patterns of WFT in Kenya. Even with the limited data set, the results reveal that F. occidentalis populations show considerable genetic differentiation between host plant species but not between regions, which suggests reduced gene flow and a possible development of biotypes. Possible consequences of the results on IPM are discussed.

Thrips, Frankliniella occidentalis (Pergande), is a major invasive pest that causes extensive yield losses in French bean and tomato in Kenya. Thrips management is based on the application of pesticides. In addition to increased environmental risks associated with pesticides, frequent use of these chemicals increases production costs and pesticide resistance. Furthermore, exports are restricted due to non-compliance to maximum residue levels in important consumer export markets, especially the European Union (EU). This study was conducted to estimate the potential benefits of the effectiveness of the icipe-developed strategy for control of western flower thrips before dissemination of the technology in Kenya, using the economic surplus model. We calculated the benefit–cost ratio, the Net Present Value (NPV) and the Internal Rate of Return (IRR) using Cost–Benefit Analysis (CBA). Assuming a maximum conservative adoption rate of 1% and a 10% discount rate for the base deterministic scenario, the NPV of the research was estimated at US$2.2 million, with an IRR of 23% and a BCR of 2.46. Sensitivity analyses indicated that the NPV, IRR and BCR increased at an increasing rate as adoption rates increased. However, as elasticities of supply and demand increased, the NPV, IRR and BCR increased at a decreasing rate. The findings demonstrate that farmers from developing countries can gain when they obtain access to suitable pest management innovations such as integrated pest management technologies. Consequently, investment in IPM technologies for suppression of western flower thrips should be enhanced.

An explicit expression for the time-dependent force on a stationary, finite-sized spherical particle located in an unsteady inhomogeneous ambient flow is presented. The force expression accounts for both viscous and compressible effects. Towards this end, a time-harmonic plane travelling wave of a given frequency propagating in a viscous compressible flow over a sphere is considered. Linearized compressible Navier–Stokes equations are solved to obtain an analytical expression for the force exerted on the particle in the frequency domain. The force obtained in the Laplace space due to a travelling wave of a given frequency and wavenumber is then generalized to any arbitrary incoming flow. This is achieved by relating the radial and tangential velocity components in the Laplace space to the surface-averaged radial velocity and volume-averaged velocity vectors respectively in the time space. Moreover an expression relating the surface-averaged radial velocity and volume-averaged velocity vector has been provided. The total force is written as a summation of the undisturbed and disturbed force (quasi-steady, inviscid-unsteady and viscous-unsteady) contributions. The force contributions thus obtained are expressed as comprising of two parts – that arising due to spatial variation in the ambient flow and the other arising due to temporal variation. The current formulation is applicable to inhomogeneous ambient flows, however in the limit of negligible Reynolds and Mach numbers. The results are applicable even for particles of sizes larger than the acoustic wavelength. The accuracy of the explicit time-domain force expression is first tested by computing the force on an 80 mm diameter particle due to a weak planar expansion fan. Extension of this formulation when nonlinear effects become important is also proposed and tested by considering strong expansion fans. The results thus obtained are compared against corresponding axisymmetric numerical simulations.

Frankliniella schultzei Trybom is a polyphagous pest and vector of tospoviruses worldwide. It occurs in dark and pale colour forms that are morphologically similar but differ in vector competency and geographic spread. In Kenya and other tropical regions, mixed populations of both colour forms are observed in similar habitats, so are considered as one species. To ascertain the taxonomic status of the two colour forms, they were characterized using morphological, molecular, biological and ecological approaches. Morphological characterization revealed differences between the colour forms on eight features and they separated into distinct clusters through principal component analysis. Restriction fragment length polymorphism of the internal transcribed spacer region (ITS-RFLP) analysis revealed differences between the two colour forms and was confirmed by differences in ITS2 sequences. Virgin pale females had female offspring (thelytoky), while virgin dark females had male offspring (arrhenotoky). Interbreeding of dark males with pale females resulted in pale females, indicating absence of interbreeding between the two colour forms. Laboratory colonies of pale forms lacked males and further analysis of F. schultzei males from Ipomoea setosa flowers in the field indicated the presence of dark males and the absence of pale males. Field surveys in Kenya indicated differences in distribution and host plant preferences among the colour forms. Lack of interbreeding, distinct host preferences and distribution, and morphological and molecular differences indicate that the two colour forms of F. schultzei could be different species. The results highlight the need for combining morphological, biological, molecular and ecological characteristics for resolving taxonomic status of closely related insects.

This paper presents the numerical simulations of flowfield over a typical Crew Module at Mach 4 for different angles-of-attack ranging from 0 to –25°. Detailed flow features such as contour of density gradient over the model, numerical oil flow and near wake vortex structures are captured very well in the present simulations. The location of the sonic line and its behaviour due to angles-of-attack is also captured in the simulations. The CP distribution on the windward and leeward side shows excellent match with the experimental results. Also, the prediction of aerodynamic coefficients shows very good agreement with the experimental results. The numerical simulation predicts CMcg, CN and CA within 8%, 4% and 3·5% respectively with respect to experimental values.

The field of electronics packaging is undergoing a significant transition to accommodate the slowing down of lithographically driven semiconductor scaling. Three-dimensional (3D) integration is an important component of this transition and promises to revolutionize the way chips are assembled and interconnected in a subsystem. In this article, we develop the key attributes of 3D integration, the enablers and the challenges that need to be overcome before widespread acceptance by industry. While we are already seeing the proliferation of applications in the memory subsystem, the best is yet to come with the heterogeneous integration of a diverse set of technologies, the mixing of lithographic nodes and an economic argument for its implementation based on overall system function, and cost rather than a narrow component-based analysis. Finally, an extension to monolithic 3D integration promises even further benefits.

Several epidemiological studies have shown that the consumption of finger millet (FM) alleviates diabetes-related complications. In the present study, the effect of finger millet whole grain (FM-WG) and bran (FM-BR) supplementation was evaluated in high-fat diet-fed LACA mice for 12 weeks. Mice were divided into four groups: control group fed a normal diet (10 % fat as energy); a group fed a high-fat diet; a group fed the same high-fat diet supplemented with FM-BR; a group fed the same high-fat diet supplemented with FM-WG. The inclusion of FM-BR at 10 % (w/w) in a high-fat diet had more beneficial effects than that of FM-WG. FM-BR supplementation prevented body weight gain, improved lipid profile and anti-inflammatory status, alleviated oxidative stress, regulated the expression levels of several obesity-related genes, increased the abundance of beneficial gut bacteria (Lactobacillus, Bifidobacteria and Roseburia) and suppressed the abundance of Enterobacter in caecal contents (P≤ 0·05). In conclusion, FM-BR supplementation could be an effective strategy for preventing high-fat diet-induced changes and developing FM-BR-enriched functional foods.

In the present study, experiments were carried out in French bean fields over two planting periods to evaluate the potential use of sticky traps for monitoring the populations of pest thrips. To this end, blue, yellow and clear sticky traps (with and without a thrips lure, i.e. Lurem-TR) were tested. Field observations on thrips catches were made at weekly intervals from the sticky traps, and absolute estimates of thrips populations and their natural enemies were made by destructive (picking leaves and flowers) and non-destructive sampling (plant tapping) of plants until crop senescence during the two planting periods. Blue traps caught two and three times more thrips compared with yellow traps over the first and second planting periods, respectively. Blue traps were more attractive to Megalurothrips sjostedti (Trybom), Frankliniella schultzei (Trybom) and Frankliniella occidentalis (Pergande), while yellow traps were only attractive to Hydatothrips adolfifriderici (Karny) and the natural enemies of thrips. The addition of Lurem-TR to the sticky traps significantly increased the capture of all thrips species, but not their natural enemies. The estimates of thrips populations from blue sticky traps with Lurem-TR were found to be highly correlated (r= 0.95; P< 0.001) with the absolute estimates of thrips using the destructive sampling method. The results demonstrate that blue sticky traps and Lurem-TR can be an efficient tool for the monitoring of thrips populations on French beans with least influence on their natural enemies.

We present an analysis of the optical nuclear spectra from the active galactic nuclei (AGN) in a sample of giant low surface brightness (GLSB) galaxies. GLSB galaxies are extreme late type spirals that are large, isolated and poorly evolved compared to regular spiral galaxies. Earlier studies have indicated that their nuclei have relatively low mass black holes. Using data from the Sloan Digital Sky Survey (SDSS), we selected a sample of 30 GLSB galaxies that showed broad Hα emission lines in their AGN spectra. In some galaxies such as UGC 6284, the broad component of Hα is more related to outflows rather than the black hole. One galaxy (UGC 6614) showed two broad components in Hα, one associated with the black hole and the other associated with an outflow event. We derived the nuclear black hole (BH) masses of 29 galaxies from their broad Hα parameters. We find that the nuclear BH masses lie in the range 105 – 107 M⊙. The bulge stellar velocity dispersion σe was determined from the underlying stellar spectra. We compared our results with the existing BH mass - velocity dispersion (MBH–σe) correlations and found that the majority of our sample lie in the low BH mass regime and below the MBH–σe correlation. The effects of galaxy orientation in the measurement of σe and the increase of σe due to the effects of bar are probable reasons for the observed offset for some galaxies, but in many galaxies the offset is real. A possible explanation for the MBH–σe offset could be lack of mergers and accretion events in the history of these galaxies which leads to a lack of BH-bulge co-evolution.

Iris yellow spot virus (IYSV) vectored by Thrips tabaci threatens profitable onion production in eastern Africa. Host plant resistance is considered to be the first line of defence against insect-transmitted virus diseases. Hence, information on resistance to IYSV and T. tabaci among common onion cultivars in Kenya is crucial for the development of integrated pest management strategies. This study evaluated the resistance to thrips and IYSV among widely grown onion cultivars in Kenya, viz. Red Pinoy, Red Creole, Bombay Red, Green Bunching and Texas Grano, over two growing seasons. Straw-coloured, diamond-shaped necrotic lesions typical of IYSV infection were observed 2 weeks after transplantation. Observations on thrips numbers per plant, IYSV disease incidence and severity, and virus intensity were undertaken to assess the resistance. Varieties differed significantly with respect to both IYSV disease incidence and thrips numbers per plant from fourth week to physiological maturity. Red Pinoy, Green Bunching and Red Creole were highly susceptible to the virus and thrips, while Texas Grano and Bombay Red were moderately resistant. There were significant differences among the varieties with regard to IYSV intensity, with the highest and the least virus intensity positively correlated with disease severity being recorded in Red Pinoy and Texas Grano, respectively. Among the varieties, Texas Grano produced the highest yield in both seasons, while Red Pinoy produced the least. Hence, Texas Grano and Bombay Red could be recommended as moderately resistant cultivars to thrips and IYSV to be grown in Kenya for markets where pungency is not preferred and preferred, respectively. Regions with high levels of thrips population and IYSV infestation are not suitable for the cultivation of Red Pinoy.

Poly(N-isopropylacrylamide) (PNIPAM) is a thermo-sensitive polymer that exhibits a lower critical solution temperature (LCST) around 305 K. Below the LCST, PNIPAM is soluble in water and above this temperature polymer chains collapse prior to aggregation. In the presence of methanol, electron paramagnetic resonance (EPR) spectroscopy suggests that, LCST of PNIPAM is depressed up to certain mole fraction of methanol (0.35 mole fraction) and it is speculated that addition of methanol affects the PNIPAM-water interactions. Above 0.35 mole fraction of methanol, LCST gets elevated to temperatures above ∼305 K (32°C) and cannot be detected up to 373 K (100 °C). The atomistic origin of this co-solvency effect on the LCST behavior is not completely understood. In the present study, we have used molecular dynamics (MD) simulations to investigate the effect of methanol-water mixtures on conformational transitions and the LCST of PNIPAM. We employ two different force fields i.e. polymer consistent force-field (PCFF) and CHARMM to study solvation dynamics and the PNIPAM LCST phase transition in various methanol-water mixture compositions (0.018, 0.09, 0.27, 0.5, and 0.98 mole fractions). Simulations are conducted at fully atomistic level for three different temperatures (260, 278, and 310 K) and radius of gyration (Rg) of PNIPAM chains was computed for determination of LCST behavior of PNIPAM.

The present article will describe the science and technology of titanium aluminide (TiAl) alloys and the engineering development of TiAl for commercial aircraft engine applications. The GEnxTM engine is the first commercial aircraft engine that is flying titanium aluminide (alloy 4822) blades and it represents a major advance in propulsion efficiency, realizing a 20% reduction in fuel consumption, a 50% reduction in noise, and an 80% reduction in NOx emissions compared with prior engines in its class. The GEnxTM uses the latest materials and design processes to reduce weight, improve performance, and reduce maintenance costs.

GE’s TiAl low-pressure turbine blade production status will be discussed along with the history of implementation. In 2006, GE began to explore near net shape casting as an alternative to the initial overstock conventional gravity casting plus machining approach. To date, more than 40,000 TiAl low-pressure turbine blades have been manufactured for the GEnxTM 1B (Boeing 787) and the GEnxTM 2B (Boeing 747-8) applications. The implementation of TiAl in other GE and non-GE engines will also be discussed.