106 research outputs found
Concentration in Knowledge Output: A case of Economics Journals
No full textThis paper assesses the degree of author concentration in seven economics journals, which were published in India during 1990-2002. To measure the degree of author concentration, Lotka's Law was used. Moreover, we also make an exploratory analysis of the geographic, economics subfield and institutional concentration in 704 economics journals. An important finding of this paper is that specialized journals in the sample report the highest degree of author concentration. This result is quite similar to the findings by Cox and Chung (1991). Furthermore, there are several instances showing that the journals lean towards certain norms; this may affect the flow of innovative ideas into economics. We conclude that a knowledge activity, involving the high degree of concentration and a biased publication process, may affect the flow of new ideas into the discipline.Concentration, Lotka's Law
The Effect of Water Cut on the Producing Trends and Downhole Multiphase Flow Conditions in Oil-Rich Shale Plays
No full textCarrier multiplication in van der Waals layered transition metal dichalcogenides
No full text© 2019, The Author(s).Carrier multiplication (CM) is a process in which high-energy free carriers relax by generation of additional electron-hole pairs rather than by heat dissipation. CM is promising disruptive improvements in photovoltaic energy conversion and light detection technologies. Current state-of-the-art nanomaterials including quantum dots and carbon nanotubes have demonstrated CM, but are not satisfactory owing to high-energy-loss and inherent difficulties with carrier extraction. Here, we report CM in van der Waals (vdW) MoTe2 and WSe2 films, and find characteristics, commencing close to the energy conservation limit and reaching up to 99% CM conversion efficiency with the standard model. This is demonstrated by ultrafast optical spectroscopy with independent approaches, photo-induced absorption, photo-induced bleach, and carrier population dynamics. Combined with a high lateral conductivity and an optimal bandgap below 1 eV, these superior CM characteristics identify vdW materials as an attractive candidate material for highly efficient and mechanically flexible solar cells in the future11sciescopu
Lotka' s Law, Co-authorship and Interdisciplinary Publishing
No full textThe robustness or breakdown of Lotka's law about the frequency distribution of scientific productivity depends on scientific cooperation, counting methods, interdisciplinary publishing and selection methods for sample collections. We have chosen to analyse the relationship using Mandelbrot's equivalent distribution model because this model is sensitive and uses the original data (scores). Five sets of authors and publications, the two sets used by Lotka, a set from High Energy Physics, a set from Microbiology and a set based on applicants to a research programme promoting young researchers have been used. It is shown that even for a sample of authors in High-Energy Physics with extremely strong co-authorship, Mandelbrot's distribution law is robust when complete-normalized (fractional) counting is used whereas complete counting results in a breakdown. In the field of Microbiology with much weaker cooperation, both counting methods result in a breakdown of Mandelbrot's law. Today a field like Microbiology with the corresponding set of journals, probably has a large content of interdisciplinary publishing and therefore no more fulfills the precondition of Lotka's law, that the total production of the authors (sources) is considered. For a set of applicants for the Emmy Noether Programme of the German Research Foundation. Mandelbrot's law breaks down despite the fact that all publications co-authored by the applicants are taken into account. In agreement with Bayes' theorem of conditional probabilities these results lead to the conjecture that any selection process of authors and/or publications causes a breakdown of Mandelbrot's law and, as a consequence Lotka's law
Ferromagnetism in MnX2 ( X = S, Se) monolayers
No full textUsing density functional theory combined with Monte Carlo (MC) simulations, we show that the two dimensional (2D) MnS2 and MnSe2 sheets are ideal magnetic semiconductors with long-range magnetic ordering and high magnetic moments (3 mu(B) per unit cell), where all the Mn atoms are ferromagnetically coupled, and the Curie temperatures (T-C) estimated for MnS2 and MnSe2 by the MC simulations are 225 and 250 K, respectively, which can be further increased to 330 K and 375 K by applying 5% biaxial tensile strains.Chemistry, PhysicalPhysics, Atomic, Molecular & ChemicalSCI(E)[email protected]
Bilateral carotid body tumor in a 13-year-old child: Our experience
No full textCarotid body tumors are rare neuroendocrine tumors derived from the extra-adrenal paraganglioma of the autonomic nervous system. Very few cases have been reported in literature in the pediatric age group <14 years of age. We present our experience in managing a Shamblin III carotid body tumor in a 13-year-old boy who underwent an unsuccessful attempt at excision at another hospital. Surgical excision of the tumor along with ligation of the internal carotid artery was done without any postoperative neurological sequel. The tumor on the contralateral side was being managed conservatively with serial follow-up
Role of C- reactive proteins in cerebro-spinal fluid in differentiating pyogenic from nonpyogenic meningitis
No full textBackground:In developing countries like India meningitis is major cause of morbidity and mortility because of delay in proper diagnosis and consequently delay in proper treatment. For the appropriate treatment of meningitis, differentiation of various types of meningitis is essential. The diagnosis of meningitis in a govt. hospitals is usually made by examination of CSF, Gram staining, AFB, CSF culture and associated clinical findings. All these laboratory techniques have their limitations. So we need a diagnostic test which is rapid, reliable and cost effective. In the present study we used CRP levels in CSF sample to differentiate pyogenic from non-pyogenic meningitis and to establish a cut off level for CRP.Methods: The study is a hospital based prospective study carried out in the setting of department of pathology, microbiology, casuality and various wards of Netaji Subash Chandra Bose Medical College Jabalpur (M.P) India during November 2014 to October 2015. During study period we took samples (Blood and CSF) from 138 cases of suspected meningitis.Results: Value of CRP was 32.50645±2.032886 in PM cases, 1.543373±0.195181 in TBM cases and VM cases value were 2.420833±0.357502. Statistically significantly higher value was observed with pyogenic meningitis cases compared to TBM and VM cases. (p<0.001). At 10 U/L cut off value, sensitivity and specificity of CSF- CRP was 93.5% and 94.4% respectively.Conclusions: On the basis of present study we concluded that CRP can be used as a rapid confirmatory test since elevated CRP are highly suggestive of pyogenic meningitis.
Our Experience in Managing A Rare Case of Sporadic Bilateral Juvenile Otosclerosis
No full textOtosclerosis constitutes a focus of localized new spongy bone formation in the labyrinthine capsule. This progressive conductive type hearing loss is a disease of young and middle aged adults. Studies have shown that the disease is twice as common in women as compared to men. The onset of hearing impairment usually appears after puberty and progresses till adulthood although the histological lesion may actually begins in early childhood or in the preadolescent years. The management modality includes surgery as well as hearing aid trial. The surgery in cases of juvenile otosclerosis however is delayed, because of the surgeon’s hesitancy in acknowledging the existence of otosclerosis in such a younger age group. With the developing surgical expertise, sophisticated diagnostic techniques and knowledge about the disease process, diagnosis and treatment can be made reliably in the younger age group. We are hereby sharing our surgical experience in managing a case of bilateral juvenile otosclerosis that presented to our outpatient department with the chief complaints of bilateral impaired hearing since six years
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