642 research outputs found
Level Crossings in Complex Two-Dimensional Potentials
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
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
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
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
© 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
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 5007 emission may be a common early-lifetime phase for star-forming galaxies at
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 .
\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 Gyr 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 Gyr and
forms only 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
undergo an extreme H+[\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 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
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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