Self-assembled granular walkers

Mechanisms of locomotion in microscopic systems are of great interest not only for technological applications, but also for the sake of understanding, and potentially harnessing, processes far from thermal equilibrium. Down-scaling is a particular challenge, and has led to a number of interesting concepts including thermal ratchet systems and asymmetric swimmers. Here we present a system which is particularly intriguing, as it is self-assembling and uses a robust mechanism which can be implemented in various settings. It consists of small spheres of different size which adhere to each other, and are subject to an oscillating (zero average) external force eld. An inherent nonlinearity in the mutual force network leads to force rectication and hence to locomotion. We present a model that accounts for the observed behaviour and demonstrates the wide applicability and potential scalability of the concept.Comment: 17 pages, 4 figure

Standardization versus adaptation of global marketing strategies in emerging market cross-border acquisitions

Purpose: The recent increase in the presence of emerging-market firms (EMFs) in global markets requires a closer examination of their international marketing strategies (including branding). This paper examines the factors behind the standardization or adaptation of global marketing strategies adopted by EMFs for their cross-border acquisitions. Methodology/Approach: This paper examines the determinants of the marketing strategies adopted by Indian and Chinese firms for their cross-border acquisitions. The drivers of the standardization/adaptation of marketing strategies (including branding) are identified using both quantitative data collected in 168 cross-border acquisitions conducted by the EMFs mentioned above and the institutional theory and organizational identity literature. Findings: Institutional factors have a stronger effect than organizational identities on global marketing strategies, including branding. The standardization of the EMFs’ marketing strategies is driven by the private statuses of the acquirers, legal distances, target countries’ 2 economic development, and the ethnic ties that exist between the home and host countries. The acquirers’ decisions to retain the targets’ brand identities, thus adapting their global marketing strategies, is related to the cultural distances, economic freedom distances and sizes of the targets. Research limitations/implications: In this study, two large emerging markets—India and China—are used to gather the empirical data; future works can expand upon this line of research and examine other EMFs. Practical Implications: The acquiring companies have to decide whether to adopt an adaption marketing strategy, with reference to the acquired targets’ local stakeholder requirements, or to incorporate their targets’ brands into their own global marketing strategies. Originality/ Value: Typically, previous work on the adaptation versus standardization of global marketing strategies adopted in the wake of cross-border deals has focused on acquisitions involving companies from developed countries; this paper extends the field of research to the EMFs of two of the most important developing countries: China and India

Kinetic modeling of microscopic processes during electron cyclotron resonance microwave plasma-assisted molecular beam epitaxial growth of GaN/GaAs-based heterostructures

Microscopic growth processes associated with GaN/GaAs molecular beam epitaxy (MBE) are examined through the introduction of a first-order kinetic model. The model is applied to the electron cyclotron resonance microwave plasma-assisted MBE (ECR-MBE) growth of a set of delta-GaNyAs1–y/GaAs strained-layer superlattices that consist of nitrided GaAs monolayers separated by GaAs spacers, and that exhibit a strong decrease of y with increasing T over the range 540–580 °C. This y(T) dependence is quantitatively explained in terms of microscopic anion exchange, and thermally activated N surface-desorption and surface-segregation processes. N surface segregation is found to be significant during GaAs overgrowth of GaNyAs1–y layers at typical GaN ECR-MBE growth temperatures, with an estimated activation energy Es ~ 0.9 eV. The observed y(T) dependence is shown to result from a combination of N surface segregation/desorption processes

Cataract prevalence, cataract surgical coverage and barriers to uptake of cataract surgical services in Pakistan: the Pakistan National Blindness and Visual Impairment Survey.

AIM: To estimate the prevalence of visual impairment and blindness caused by cataract, the prevalence of aphakia/pseudophakia, cataract surgical coverage (CSC) and to identify barriers to the uptake of cataract services among adults aged >or=30 years in Pakistan. METHODS: Probability proportional-to-size procedures were used to select a nationally representative sample of adults. Each subject underwent interview, visual acuity measurement, autorefraction, biometry and ophthalmic examination. Those that saw <6/12 in either eye underwent a more intensive examination procedure including corrected visual acuity, slit lamp and dilated fundus examination. CSC was calculated for different levels of visual loss by person and by eye. Individuals with <6/60 in the better eye as a result of cataract were interviewed regarding barriers. RESULTS: 16 507 Adults were examined (95.5% response rate). The crude prevalence of blindness (presenting <3/60 in the better eye) caused by bilateral cataract was 1.75% (95% CI 1.55%, 1.96%). 1317 Participants (633 men; 684 women) had undergone cataract surgery in one or both eyes, giving a crude prevalence of 8.0% (95% CI 7.6%, 8.4%). The CSC (persons) at <3/60, <6/60 and <6/18 were 77.1%, 69.3% and 43.7%, respectively. The CSC (eyes) at <3/60, <6/60 and <6/18 were 61.4%, 52.2% and 40.7%, respectively. Cost of surgery (76.1%) was the main barrier to surgery. CONCLUSION: Approximately 570 000 adults are estimated to be blind (<3/60) as a result of cataract in Pakistan, and 3,560000 eyes have a visual acuity of <6/60 because of cataract. Overall, the national surgical coverage is good but underserved populations have been identified

Pest-predator spatial relationships in winter rape: implications for integrated crop management

Douglas Warner, Les J Allen-Williams, Andrew W Ferguson, and Ingrid H Williams, 'Pest–predator spatial relationships in winter rape: implications for integrated crop management', Pest Management Science, Vol. 56 (11): 977-982, November 2000, doi: 10.1002/1526-4998(200011)56:113.0.CO;2-U. Copyright © 2000 Society of Chemical IndustryThe brassica pod midge (Dasineura brassicae) is an important and widespread pest of winter and spring oilseed rape throughout Europe. Pods infested by D brassicae larvae split prematurely, releasing seeds, and the larvae drop to the soil into which they burrow to pupate. At this stage in its lifecycle D brassicae is potentially vulnerable to predation by carabid beetles foraging on the soil surface. This is the first study in the UK to focus on carabid beetles as predators of D brassicae in the oilseed rape crop. The spatio-temporal distributions of larvae of D brassicae dropping to the soil from the crop canopy and of adult carabid beetles active on the soil surface were analysed in two consecutive years. Insect samples were collected from spatially referenced sampling points across each crop. Counts of insects were mapped and analysed, and the degree of spatial association between predator and prey determined using Spatial Analysis by Distance Indices (SADIE). Carabid species abundant and active during peak drop of first generation D brassicae larvae included Agonum dorsale, Amara similata, Harpalus rufipes and Nebria brevicollis. The larvae of D brassicae had a marked edge distribution within the crop. SADIE analysis revealed significant spatial association between larvae of D brassicae and adult H rufipes (P <0.05) in 1998, but not with adults of A dorsale, A similata or N brevicollis. In 1999, there was strong spatial association only between larvae of D brassicae and adult A dorsale (P <0.01). Aggregation of N brevicollis adults occurred in some areas of greatest D brassicae larval counts in 1999, but overall spatial association was not signi®cant. The distributions are discussed in terms of their relevance to integrated crop management (ICM) strategies and spatial targeting of insecticides.Peer reviewe

(In) Direct Effects of Customer-Defined Market Orientation on Brand Loyalty through Purchase Intention and Brand Image: A Parallel Mediation Approach

This study investigates the impact of market orientation on brand loyalty, primarily through variables pertaining to the purchase intention and brand image. In order to achieve this aim, this study have resorted to testing the relationships between customer-defined market orientation and purchase intention, and the brand image, leading to brand loyalty. In this regard, the study is quantitative in nature, and uses the cross-sectional design. For this purpose, the primary data were collected from gold jewelry customers (n = 413) from Karachi, Pakistan. Three key findings emerged from the structural model testing. The first finding revealed that the customer, competitor and interventional orientation are positively associated with the purchase intention, brand image and loyalty of gold jewelry customers. Secondly, in simple mediation, the purchase intentions and brand image tend to fully mediate the impact of customer orientation, and competitor orientation on the brand loyalty of gold jewelry customers, while partially mediating the association between the interfunctional coordination and brand loyalty. The third finding revealed that, in parallel to the mediation effect, the impact of customer, competitor and interfunctional orientation on brand loyalty is fully mediated by the purchase intention and brand image. This research is useful for gold jewelry businesses and business owners, since on a comparative level, less research has been conducted in the domestic industry of Pakistan

Effects of zinc oxide nanoparticles (ZnO NPs) and some plant pathogens on the growth and nodulation of lentil (Lens culinaris Medik.)

Effects of ZnO nanoparticles (NPs) were studied on lentil plants inoculated with Alternaria alternata, Fusarium oxysporum f. sp. lentis, Xanthomonas axonopodis pv. phaseoli, Pseudomonas syringae pv. syringae and Meloidogyne incognita. Plant growth, chlorophyll, carotenoid contents, nitrate reductase (NR) activity and nodulation of lentil both in the presence and absence of Rhizobium sp. were examined in a pot test. Inoculation of plants with A. alternata / F. oxysporum f. sp. lentis / X. axonopodis pv. phaseoli / P. syringae pv. syringae or M. incognita caused a significant reduction in plant growth, number of pods per plant, chlorophyll, carotenoids and NR activity over uninoculated control. Inoculation of plants with Rhizobium sp. with or without pathogen increased plant growth and number of pods per plant, chlorophyll, carotenoids and NR activity. When plants were grown without Rhizobium, a foliar spray of plants with 10 ml solution of 0.1 mg ml–1of ZnO NPs per plant caused a significant increase in plant growth and number of pods, chlorophyll, carotenoid contents and NR activity in both inoculated and uninoculated plants. Spray of ZnO NPs to plants inoculated with Rhizobium sp. caused non significant increase in plant growth, number of pods per plant, chlorophyll, carotenoid contents and NR activity when plants were either uninoculated or inoculated with pathogens. Numbers of nodules per root system were high in plants treated with Rhizobium sp. but foliar spray of ZnO NPs had adverse effect on nodulation. Inoculation of plants with test pathogens also reduced nodulation. Spray of ZnO NPs to plants reduced galling, nematode multiplication, wilt, blight and leaf spot disease severity indices