9,759 research outputs found

    Band structures of laterally coupled quantum dots, accounting for electromechanical effects

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    In a series of recent papers we demonstrated that coupled electro-mechanical effects can lead to pronounced contributions in band structure calculations of low dimensional semiconductor nanostructures (LDSNs) such as quantum dots, wires, and even wells. Some such effects are essentially nonlinear. Both strain and piezoelectric effects have been used as tuning parameters for the optical response of LDSNs in photonics, band gap engineering and other applications. However, these effects have been largely neglected in literature while laterally coupled quantum dots (QDs) have been studied. The superposition of electron wave functions in these QDs become important in the design of optoelectronic devices as well in tayloring properties of QDs in other applications areas. At the same time, laterally grown QDs coupled with electric and mechanical fields are becoming increasingly important in many applications of LDSN-based systems, in particular where the tunneling of electron wave function through wetting layer (WL) becomes important and the distance between the dots is treated as a tuning parameter. Indeed, as electric and elastic effects are often significant in LDSNs, it is reasonable to expect that the separation between the QDs may also be used as a tuning parameter in the application of logic devices, for example, OR gates, AND gates and others. In this contribution, by using the fully coupled model of electroelasticity, we build on our previous results while analyzing the influence of these effects on optoelectronic properties of QDs. Results are reported for III-V type semiconductors with a major focus given to GaN/AlN based QD systems

    Observation of pseudogap in MgB2

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    Pseudogap phase in superconductors continues to be an outstanding puzzle that differentiates unconventional superconductors from the conventional ones (BCS-superconductors). Employing high resolution photoemission spectroscopy on a highly dense conventional superconductor, MgB2, we discover an interesting scenario. While the spectral evolution close to the Fermi energy is commensurate to BCS descriptions as expected, the spectra in the wider energy range reveal emergence of a pseudogap much above the superconducting transition temperature indicating apparent departure from the BCS scenario. The energy scale of the pseudogap is comparable to the energy of E2g phonon mode responsible for superconductivity in MgB2 and the pseudogap can be attributed to the effect of electron-phonon coupling on the electronic structure. These results reveal a scenario of the emergence of the superconducting gap within an electron-phonon coupling induced pseudogap.Comment: 4 figure

    The Cosmology of Massless String Modes

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    We consider the spacetime dynamics of a gas of closed strings in the context of General Relativity in a background of arbitrary spatial dimensions. Our motivation is primarily late time String Gas Cosmology, where such a spacetime picture has to emerge after the dilaton has stabilized. We find that after accounting for the thermodynamics of a gas of strings, only string modes which are massless at the self-dual radius are relevant, and that they lead to a dynamics which is qualitatively different from that induced by the modes usually considered in the literature. In the context of an ansatz with three large spatial dimensions and an arbitrary number of small extra dimensions, we obtain isotropic stabilization of these extra dimensions at the self-dual radius. This stabilization occurs for fixed dilaton, and is induced by the special string states we focus on. The three large dimensions undergo a regular Friedmann-Robertson-Walker expansion. We also show that this framework for late-time cosmology is consistent with observational bounds.Comment: 15 pages, no figures, references added (again

    Vehicle to Vehicle Communication System for Smart Cities

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    A Vehicle-to-Vehicle (V2V) communication system for smart cities is proposed here. The V2V communication system is an advance wireless technology to reduce the number of fatal roadway accidents by providing early warning messages. For development of smart cities V2V and V2R are important to reduce road accidents on highways. It gives ease of access by providing different facilities such as ATM transaction, accidents safety messages to the transport or central unit. Based on a careful analysis of application requirements, an effective protocol can be used, which comprising congestion control policies, service differentiation mechanisms and methods for emergency warning dissemination. The proposed protocol achieves low latency in delivering emergency warnings and use of efficient bandwidth in stressful road scenarios. This system uses WSN for communication between two vehicle modules

    Participatory cotton breeding for organic and low input farming in Central India

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    Up to 80% of world’s organic cotton is produced in India. However, involved producers are facing increased difficulties to find suitable cultivars. Few hybrids selected for high input farming and genetically-modified (GM) cotton, which is explicitly excluded in organic farming, are presently dominating the Indian seed market. In addition farmers have lost their traditional knowledge on seed production and hybrid seed needs to be purchased each season

    A rare cause of epididymo-orchitis

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    Epididymo-orchitis is an inflammatory lesion of the testis and epididymis with a lymphocytic exudate. Patients with acute epididymo-orchitis typically present with scrotal pain, swelling, tenderness and fever. Here, we present a patient with scrotal pain and hemiscrotal swelling as the main complaints; however further investigations revealed a completely different and rare diagnosis. Zinner’s syndrome is a very rare developmental anomaly of the Wolffian duct. To date, only about 200 cases have been diagnosed. It is a triad of unilateral renal agenesis, ipsilateral seminal vesicle cyst and ejaculatory duct obstruction. Some patients remain asymptomatic and discovered incidentally, while others present with symptoms related to seminal vesicle cysts or ejaculatory duct obstruction: voiding or ejaculatory difficulty or pain. Treatment options include transurethral or transrectal aspiration and percutaneous drainage, however both are linked to an increased risk of recurrence. Symptomatic, complicated and recurrent cyst will require excision of the cyst, either laparoscopically or robotically

    Automatic Classification of Medicinal Plants Using State-Of-The-Art Pre-Trained Neural Networks

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    Now a days every mankind is suffering due to infections. Ayurveda, the science of life helped to take preventive measures which boost our immunity.  It is plant-based science. Many medicinal plants found useful in daily life of common people for boosting immunity. Identifying the plant species having medicinal plant is challenging, it requires botanical expert. In the process of manual identification, botanical experts use various plant features as the identification keys, which are examined adaptively and progressively to identify plant species. The shortage of experts and trained taxonomist created global taxonomic impediment problem which is one of the major challenges.  Various researchers have worked in the field of automatic classification of plants since the last decade. The leaf is considered as primary input as it is available throughout the whole year. The research paper mainly focuses on the study of transfer learning approach for medicinal plant classification, which reuse already developed model at the starting point for model on a second task. Transfer learning approach is a black box approach used for image classification and many more applications by extracting features from an image. Some of the transfer learning models are MobileNet-V1, VGG-19, ResNet-50, VGG-16. Here it uses Mendeley dataset of Indian medicinal plant species which is freely available. Output layer classifies the species of leaves. The result provides evaluation and variations of above listed features extracted models. MobileNetV1 achieves maximum accuracy of 98%

    AWARENESS, KNOWLEDGE AND ATTITUDE ABOUT DENGUE AMONG SOCIETY

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    Objective: The survey about dengue was carried out to gather the information about dengue fever, create awareness among the people. To determined the index of knowledge, attitude and awareness among the surveyed population about dengue. Methods: The questionnaire was prepared under the guidance of a pharmacologist. Pilot study was conducted among ten nos. of the population prior actual study. Questionnaire was revised and finalized according to an input of the pilot study. This questionnaire presented to the hundred peoples of different age group. Method involves face to face interview and seeking answers for different questions. Responses were recorded for further analysis and interpretation. Responses were sorted and analyzed. Different questions were categorized into the domain of awareness, knowledge and attitude. Data was presented in the form of graphs. Results: Percentage of awareness, knowledge and attitude found to be 59, 44, 52 respectively. It is observed that three parameters are almost in the range of fifty percent. Precautions plays vital role in prevention of Dengue. Conclusion: it is concluded that there is scope for improvement for creating awareness, knowledge and attitude among the surveyed population as representative of the general population. This may help to overcome the risk of this communicable and deadly disease
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