654 research outputs found

    Topological Superconductivity by Engineering Noncollinear Magnetism in Magnet/ Superconductor Heterostructures: A Realistic Prescription for 2D Kitaev Model

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    We report on a realistic and rather general scheme where noncollinear magnetic textures proximitized with the most common ss-wave superconductor can appear as the alternative to pp-wave superconductor{--}the prime proposal to realize two-dimensional (2D) Kitaev model for topological superconductors (TSCs) hosting Majorana flat edge mode (MFEM). A general minimal Hamiltonian suitable for magnet/superconductor heterostructures reveals robust MFEM within the gap of Shiba bands due to the emergence of an effective ``px+pyp_x+p_y"-type pp-wave pairing, spatially localized at the edges of a 2D magnetic domain of spin-spiral. We finally verify this concept by considering Mn (Cr) monolayer grown on a ss-wave superconducting substrate, Nb(110) under strain (Nb(001)). In both 2D cases, the antiferromagnetic spin-spiral solutions exhibit robust MFEM at certain domain edges that is beyond the scope of the trivial extension of 1D spin-chain model in 2D. This approach, particularly when the MFEM appears in the TSC phase for such heterostructure materials, offers a perspective to extend the realm of the TSC in 2D.Comment: This is the published versio

    Stress mitigation strategies of plant growth-promoting rhizobacteria: Plant growth-promoting rhizobacteria mechanisms

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    One of the major challenges that the world is facing currently is the inadequate amount of food production with high nutrient content in accordance with the increase in population size. Moreover, availability of cultivable area with fertile soil is reducing day by day owing to ever increasing population. Further, water scarcity and expensive agricultural equipment have led to the use of agrochemicals and untreated water. Excessive use of chemical fertilizers to increase crop yield have resulted in deleterious effects on the environment, health and economy, which can be overcome to a great extent by employing biological fertilizers. There are various microbes that grows in the rhizospheric region of plants known as plant growth-promoting rhizobacteria (PGPR). PGPR act by direct and indirect modes to stimulate plant growth and improve stress reduction in plants. PGPRs are used for potential agriculture practices having a wide range of benefits like increase in nutrients content, healthy growth of crops, production of phytohormones, prevention from heavy metal stress conditions and increase in crop yield. This review reports recent studies in crop improvement strategies using PGPR and describes the mechanisms involved. The potential mechanisms of PGPR and its allies pave the way for sustainable development towards agriculture and commercialization of potential bacteria

    The Stock Market Evaluation of IPO-Firm Takeovers

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    We conduct an event study to assess the stock market evaluation of public takeover announcements. Unlike the majority of previous research, we specifically focus on acquisitions targeted at newly public IPO-firms and show that the stock market positively evaluates these M&As as R&D. However, bidders' abnormal announcement returns are significantly lower for takeovers directed at targets with critical intangible assets and innovative capabilities inalienably bound to their initial owners than for those that have internally accumulated respective resources and capabilities. We explain these findings with the acquirer's post-acquisition dependence on continued access to the IPO-firm founders' target-specific human capital. Our results contribute to literature in that they show that the stock market perceives these potential impediments to successful exploitation of acquired strategic resources and thus identify a potential cause for heretofore mostly inconsistent evidence on bidder abnormal returns in corporate takeovers found in previous research

    Large expert-curated database for benchmarking document similarity detection in biomedical literature search

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    Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

    The Diversification Decision: the Economics of the Manager's Perspective.

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    In this study we try to identify the factors that (a) determine the decision of a firm to diversify, (b) determine the type of market (related or unrelated) to be entered, and (c) determine the mode of entry (acquisition or denovo) in such markets. The theoretical predictors are arrived at by using the following principles. (a) The presence of excess resources coupled with market failure to trade in these resources provide the basic economic impetus for diversification. (b) Managers within a firm decide on strategic moves based on information which is more often than not unavailable to the market at large. By classifying the resources available with a firm into three categories, we are able to make predictions about the type of markets a firm would prefer to enter. The predictions about mode of entry were based on an economic analysis of the two modes of entry, modified by principle (b) above. The theoretical models were tested on a sample of 177 diversification moves. The results show that there is a statistical relationship between the different class of resources and the types of diversification. A single equation estimation of the predictions regarding the mode of entry provides only partial support for the predictions. However, when we explicitly incorporate the interdependence of the mode of entry and the type of entry in a simultaneous equation framework, almost all theoretical predictions are supported with a high degree of statistical significance. We reach the specific conclusion that the decision regarding the mode of entry is heavily influenced by the decision regarding the type of entered market but not vice versa.Ph.D.ManagementUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/160773/1/8600421.pd

    AirBNB - Business Model Development and Future Challenges

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    In 2007, Brian Chesky and Joe Gebbia founded Airbnb. Chesky and Gebbia had met several years earlier as students at the Rhode Island School of Design. After initially working in Los Angeles after graduation, Chesky decided to move to San Francisco, where Gebbia was living. The two shared an apartment but were struggling to pay their rent. While brainstorming ideas to earn more money, they came up with the idea to rent out the three airbeds they had available. There was an upcoming design conference in their neighbourhood, and all of the nearby hotels were sold out. They set up a quick website to advertise their offer for an overnight stay on an airbed in their apartment, along with breakfast in the morning. One would normally expect to find a few younger 20-somethings who might be interested in sleeping on someone’s couch during the conference. However, the three people who stayed with them were a 45-year-old father of five from Utah, a 35-year-old woman from Boston, and a man from India. Given the interest in their apartment airbeds from a wide variety of people, Chesky and Gebbia decided to expand their small idea and Airbnb was formed. Engineer Nathan Blecharczyk was added as the third co-founder.
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