642 research outputs found

    Level Crossings in Complex Two-Dimensional Potentials

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    Two-dimensional PT-symmetric quantum-mechanical systems with the complex cubic potential V_{12}=x^2+y^2+igxy^2 and the complex Henon-Heiles potential V_{HH}=x^2+y^2+ig(xy^2-x^3/3) are investigated. Using numerical and perturbative methods, energy spectra are obtained to high levels. Although both potentials respect the PT symmetry, the complex energy eigenvalues appear when level crossing happens between same parity eigenstates.Comment: 9 pages, 4 figures. Submitted as a conference proceeding of PHHQP

    Digital processing system for developing countries

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    An effort was undertaken to perform simple digital processing tasks using pre-existing general purpose digital computers. An experimental software package, LIGMALS, was obtained and modified for this purpose. The resulting software permits basic processing tasks to be performed including level slicing, gray mapping and ratio processing. The experience gained in this project indicates a possible direction which may be used by other developing countries to obtain digital processing capabilities

    Investigation of the agricultural resources in Sri Lanka

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    The author has identified the following significant results. Several in-house capabilities were developed. The facilities to prepare color composites of excellent quality were developed, using bulk B/W 70 mm transparencies or 1:1,000,000 positive transparencies. These color composites were studied through optical devices on light tables. A zoom transfer scope was also added, enabling direct transfer of LANDSAT composite data on to base maps

    The impact of COVID-19 on BAME populations: a systematic review of experiences and perspectives

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    Black, Asian, Minority Ethnic (BAME) populations have been disproportionately affected by COVID-19, having amongst the highest rates of infection and mortality. Additional risk factors for BAME populations include older age and living with poverty and deprivation. Information has emerged, but peer reviewed research and literature examining the experiences and/or perspectives of this most recent of diseases on BAME populations is fragmented and lacks coalescence. This systematic review will therefore bring together and integrate existing and emergent evidence around the experiences and/or perspectives of COVID-19 on BAME populations

    Evidence to inform education, training and supportive work environments for midwives involved in the care of women with female genital mutilation: A review of global experience

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    © 2014 Elsevier Ltd. Objective: to identify how midwives in low and middle income countries (LMIC) and high income countries (HIC) care for women with female genital mutilation (FGM), their perceived challenges and what professional development and workplace strategies might better support midwives to provide appropriate quality care. Design: an integrative review involving a narrative synthesis of the literature was undertaken to include peer reviewed research literature published between 2004 and 2014. Findings: 10 papers were included in the review, two from LMIC and eight from HIC. A lack of technical knowledge and limited cultural competency was identified, as well as socio-cultural challenges in the abandonment process of the practice, particularly in LMIC settings. Training in the area of FGM was limited. One study reported the outcomes of an education initiative that was found to be beneficial. Key conclusions: professional education and training, a working environment supported by guidelines and responsive policy and community education, are necessary to enable midwives to improve the care of women with FGM and advocate against the practice. Implications for practice: improved opportunities for midwives to learn about FGM and receive advice and support, alongside opportunities for collaborative practice in contexts that enable the effective reporting of FGM to authorities, may be beneficial and require further investigation

    Quantum tunneling as a classical anomaly

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    Classical mechanics is a singular theory in that real-energy classical particles can never enter classically forbidden regions. However, if one regulates classical mechanics by allowing the energy E of a particle to be complex, the particle exhibits quantum-like behavior: Complex-energy classical particles can travel between classically allowed regions separated by potential barriers. When Im(E) -> 0, the classical tunneling probabilities persist. Hence, one can interpret quantum tunneling as an anomaly. A numerical comparison of complex classical tunneling probabilities with quantum tunneling probabilities leads to the conjecture that as ReE increases, complex classical tunneling probabilities approach the corresponding quantum probabilities. Thus, this work attempts to generalize the Bohr correspondence principle from classically allowed to classically forbidden regions.Comment: 12 pages, 7 figure

    ZFOURGE: Extreme 5007A˚\AA emission may be a common early-lifetime phase for star-forming galaxies at z>2.5z > 2.5

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    Using the \prospector\ spectral energy distribution (SED) fitting code, we analyze the properties of 19 Extreme Emission Line Galaxies (EELGs) identified in the bluest composite SED in the \zfourge\ survey at 2.5z42.5 \leq z \leq 4. \prospector\ includes a physical model for nebular emission and returns probability distributions for stellar mass, stellar metallicity, dust attenuation, and nonparametric star formation history (SFH). The EELGs show evidence for a starburst in the most recent 50 Myr, with the median EELG having a specific star formation rate (sSFR) of 4.6 Gyr1^{-1} and forming 15\% of its mass in this short time. For a sample of more typical star-forming galaxies (SFGs) at the same redshifts, the median SFG has a sSFR of 1.1 Gyr1^{-1} and forms only 4%4\% of its mass in the last 50 Myr. We find that virtually all of our EELGs have rising SFHs, while most of our SFGs do not. From our analysis, we hypothesize that many, if not most, star-forming galaxies at z2.5z \geq 2.5 undergo an extreme Hβ\beta+[\hbox{{\rm O}\kern 0.1em{\sc iii}}] emission line phase early in their lifetimes. In a companion paper, we obtain spectroscopic confirmation of the EELGs as part of our {\sc MOSEL} survey. In the future, explorations of uncertainties in modeling the UV slope for galaxies at z>2z>2 are needed to better constrain their properties, e.g. stellar metallicities.Comment: 11 pages, 5 figures (main figure is fig 5), accepted for publication in Ap

    Hypoglycemic Effects of Nyctanthes arbor-tristis L Flower Extract in vitro

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    Boiled flowers of Nyctanthes arbor-tristis L (Family: Oleaceae; Sepalika in Sinhala; Night Jasmin in English) has traditionally been used in Sri Lankan Ayurvedic system to manage diabetes. Previously it has been shown that the aqueous flower extract (AFE) could produce hypoglycemic effects in mice. However, the exact mechanisms are not known. Hence the present study aimed to investigate the mechanisms involved using in vitro assays. Fresh flowers were shade dried, extracted with distilled water and freeze dried. Preliminary phytochemical screening was conducted using standard methods and confirmed using thin layer chromatography. The total phenolic and flavonoid content was determined at 1.5 mg/ml dose using Gallic acid and Quercetin as respective standards. Hypoglycemic activity was studied in vitro α-amylase assay (n=6) with Acarbose as the standard using mice equivalent doses (1.5, 3, 5 mg/ml) and glucose transport across the yeast cells was conducted at 5, 10, 25 and 50 mM glucose concentrations. Phytochemical screening revealed the presence of flavonoids, saponins, unsaturated sterols and triterpenes and cardiac glycosides. AFE resulted in 600 Quercetin equivalents for total flavonoids and 1.6 Gallic acid equivalents for phenols, both of which increased in a linear mode with increasing concentrations. A significant (p<0.05) inhibition of α-amylase enzyme was revealed with increasing doses (1.5 mg/ml-60%, 3 mg/ml-52%, 5 mg/ml) giving IC50 value of 3 mg/ml compared to the standard. Both 1.5 mg/ml and 3 mg/ml promoted glucose uptake by yeast cells with increasing glucose concentrations. However, 5 mg/ml exhibited the maximum absorption only at 5 mM of glucose indicating dose independent trend. The present findings confirm that N. arbor-tristis exerts its antidiabetic activity via inhibition of α-amylase enzyme and increasing glucose transportation across the cell membranes. Fractionation and isolation of compounds are required for effective utilization as therapeutic agent.Keywords: Nyctanthes arbor-tristis, Aqueous extract, Hypoglycemia, Alpha amylase, Yeast cell uptak
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