551 research outputs found
Quantum Discord for Generalized Bloch Sphere States
In this study for particular states of bipartite quantum system in 2n?2m
dimensional Hilbert space state, similar to m or n-qubit density matrices
represented in Bloch sphere we call them generalized Bloch sphere states(GBSS),
we give an efficient optimization procedure so that analytic evaluation of
quantum discord can be performed. Using this optimization procedure, we find an
exact analytical formula for the optimum positive operator valued measure
(POVM) that maximize the measure of the classical correlation for these states.
The presented optimization procedure also is used to show that for any concave
entropy function the same POVMs are sufficient for quantum discord of mentioned
states. Furthermore, We show that such optimization procedure can be used to
calculate the geometric measure of quantum discord (GMQD) and then an explicit
formula for GMQD is given. Finally, a complete geometric view is presented for
quantum discord of GBSS. Keywords: Quantum Discord, Generalized Bloch Sphere
States, Dirac matrices, Bipartite Quantum System. PACs Index: 03.67.-a,
03.65.Ta, 03.65.UdComment: 26 pages. arXiv admin note: text overlap with arXiv:1107.5174 by
other author
Where tulips and crocuses are popular food snacks: Kurdish traditional foraging reveals traces of mobile pastoralism in Southern Iraqi Kurdistan
Background: Iraqi Kurdistan is a special hotspot for bio-cultural diversity and for investigating patterns of traditional wild food plant foraging, considering that this area was the home of the first Neolithic communities and has been, over millennia, a crossroad of different civilizations and cultures. The aim of this ethnobotanical field study was to cross-culturally compare the wild food plants traditionally gathered by Kurdish Muslims and those gathered by the ancient Kurdish Kakai (Yarsan) religious group and to possibly better understand the human ecology behind these practices. Methods: Twelve villages were visited and 123 study participants (55 Kakai and 68 Muslim Kurds) were interviewed on the specific topic of the wild food plants they currently gather and consume. Results: The culinary use of 54 folk wild plant taxa (corresponding to 65 botanical taxa) and two folk wild mushroom taxa were documented. While Kakais and Muslims do share a majority of the quoted food plants and also their uses, among the plant ingredients exclusively and commonly quoted by Muslims non-weedy plants are slightly preponderant. Moreover, more than half of the overall recorded wild food plants are used raw as snacks, i.e. plant parts are consumed on the spot after their gathering and only sometimes do they enter into the domestic arena. Among them, it is worth mentioning the consumption of raw wild crocus corms, also still common in Turkish Kurdistan and that of wild tulip bulbs, which was documented to be popular until the beginning of the twentieth century in the Middle East. Comparison with other ethnobotanical field studies recently conducted among surrounding populations has shown that Kurds tend to gather and consume the largest number of non-weedy wild vegetables. Conclusion: The collected data indicate robust traces of nomadic pastoralism in Kurdish traditional foraging. This finding confirms that studies on wild food plant gathering in the Fertile Crescent and Turco-Arabic-Iranic regions of the Middle East are crucial for understanding the possible evolution of wild food plant gathering through history within the post-Neolithic continuum between pastoralism and horticulturalism
Bilateral stellate neuroretinitis revealing a pheochromocytoma
Neuroretinitis (NR) is an inflammatory disorder characterized by optic disc edema and subsequent formation of a macular star. We present a case of a 33 year old woman patient admitted for a progressive bilateral visual loss since two weeks. Fundus examination showed bilateral stellate neuroretinitis. Physical examination revealed a malignant hypertension of 210/150mmHg. Magnetic resonance imaging identified a left suprarenal mass, whereas urinary catecholamine level was abnormally high which supported a diagnosis of pheochromocytoma.The patient underwent a laparoscopic left suprarenal adrenalectomy after successful control of blood pressure. histopathologic examination confirmed the diagnosis of pheochromocytoma. Visual acuity was restored and the retinal alterations disappeared 7 months after surgery
Weakly Nonlinear Analysis of Electroconvection in a Suspended Fluid Film
It has been experimentally observed that weakly conducting suspended films of
smectic liquid crystals undergo electroconvection when subjected to a large
enough potential difference. The resulting counter-rotating vortices form a
very simple convection pattern and exhibit a variety of interesting nonlinear
effects. The linear stability problem for this system has recently been solved.
The convection mechanism, which involves charge separation at the free surfaces
of the film, is applicable to any sufficiently two-dimensional fluid. In this
paper, we derive an amplitude equation which describes the weakly nonlinear
regime, by starting from the basic electrohydrodynamic equations. This regime
has been the subject of several recent experimental studies. The lowest order
amplitude equation we derive is of the Ginzburg-Landau form, and describes a
forward bifurcation as is observed experimentally. The coefficients of the
amplitude equation are calculated and compared with the values independently
deduced from the linear stability calculation.Comment: 26 pages, 2 included eps figures, submitted to Phys Rev E. For more
information, see http://mobydick.physics.utoronto.c
Electroconvection in a Suspended Fluid Film: A Linear Stability Analysis
A suspended fluid film with two free surfaces convects when a sufficiently
large voltage is applied across it. We present a linear stability analysis for
this system. The forces driving convection are due to the interaction of the
applied electric field with space charge which develops near the free surfaces.
Our analysis is similar to that for the two-dimensional B\'enard problem, but
with important differences due to coupling between the charge distribution and
the field. We find the neutral stability boundary of a dimensionless control
parameter as a function of the dimensionless wave number .
, which is proportional to the square of the applied voltage, is
analogous to the Rayleigh number. The critical values and
are found from the minimum of the stability boundary, and its
curvature at the minimum gives the correlation length . The
characteristic time scale , which depends on a second dimensionless
parameter , analogous to the Prandtl number, is determined from the
linear growth rate near onset. and are coefficients in the
Ginzburg-Landau amplitude equation which describes the flow pattern near onset
in this system. We compare our results to recent experiments.Comment: 36 pages, 7 included eps figures, submitted to Phys Rev E. For more
info, see http://mobydick.physics.utoronto.ca
Preliminary study on phosphate solubilizing Bacillus subtilis strain Q3 and Paenibacillus sp. strain Q6 for improving cotton growth under alkaline conditions
Background Low phosphorus availability limits crop production in alkaline calcareous soils in semi-arid regions including Pakistan. Phosphate solubilizing bacteria may improve crop growth on alkaline calcareous soils due to their ability to enhance P availability. Methods Twenty rhizobacterial isolates (Q1–Q20) were isolated from rhizosphere of cotton and characterized for their growth promoting attributes in vitro. The selected phosphate solubilizing isolates were further screened for their ability to improve cotton growth under axenic conditions (jar trial). The phosphorus solubilization capacities of selected strains were quantified and these strains were identified through 16S rDNA sequencing. Results Isolates Q2, Q3, Q6, Q7, Q8, Q13 and Q14 were able to solubilize phosphate from insoluble sources. Most of these isolates also possessed other traits including catalase activity and ammonia production. The growth promotion assay showed that Q3 was significantly better than most of the other isolates followed by Q6. Maximum root colonization (4.34 × 106 cfu g−1) was observed in case of isolate Q6 followed by Q3. The phosphorus solubilization capacities of these strains were quantified, showing a maximum phosphorus solubilization by Q3 (optical density 2.605 ± 0.06) followed by the Q6 strain. The strain Q3 was identified as Bacillus subtilis (accession # KX788864) and Q6 as Paenibacillus sp. (accession # KX788865) through 16S rDNA sequencing. Discussion The bacterial isolates varied in their abilities for different growth promoting traits. The selected PGPR Bacillus subtilis strain Q3 and Paenibacillus sp. strain Q6 have multifarious growth promoting traits including ability to grow at higher EC and pH levels, and phosphorus solubilizing ability. These strains can efficiently colonize cotton roots under salt affected soils and help plants in phosphorus nutrition. It is concluded that both strains are potential candidates for promoting cotton growth under alkaline conditions, however further investigation is required to determine their potential for field application
Annular electroconvection with shear
We report experiments on convection driven by a radial electrical force in
suspended annular smectic A liquid crystal films. In the absence of an
externally imposed azimuthal shear, a stationary one-dimensional (1D) pattern
consisting of symmetric vortex pairs is formed via a supercritical transition
at the onset of convection. Shearing reduces the symmetries of the base state
and produces a traveling 1D pattern whose basic periodic unit is a pair of
asymmetric vortices. For a sufficiently large shear, the primary bifurcation
changes from supercritical to subcritical. We describe measurements of the
resulting hysteresis as a function of the shear at radius ratio . This simple pattern forming system has an unusual combination of
symmetries and control parameters and should be amenable to quantitative
theoretical analysis.Comment: 12 preprint pages, 3 figures in 2 parts each. For more info, see
http://mobydick.physics.utoronto.c
Seagrass meadows are important sources of reef island-building sediment
This is the final version. Available on open access from Nature Research via the DOI in this recordThe future vulnerability of low-lying atoll nations is inextricably linked to the production of island-building carbonate sediments by organisms living in their adjacent marine environments. Seagrass meadows are commonly found adjacent to reef islands, but their potential role as sources of reef island-building sediments has been overlooked. Here, we quantify rates of sediment production by seagrass epibionts in a reef island sediment supply context. Total seagrass epibiont sediment production at our study site (Huvadhoo Atoll, Maldives) was 853,000 ± 90,000 kg CaCO3 yr-1 over an area of 1.1 km2. Of this total sediment production, 541,000 ± 23,000 kg CaCO3 yr-1 was estimated to be suitable to contribute to reef island building (i.e., sand-sized, post-agitation). Our findings highlight a previously unrecognised and highly valuable ecosystem service provided by tropical seagrass meadows as important potential sources of reef island-building sediment. This study, therefore, presents a new and compelling geomorphic argument for seagrass conservation.British Society for Geomorpholog
The Impact Of Glare During Daylight on Driving Performance: An Experimental Setup
An Advanced Rear Visualization (ARV) based on camera
technology is becoming more widely available in the automobile market as it increases the ability to see beyond the area of a mirror's image as well as helping to eliminate the driver’s blind spot. Besides, it assists the driver in parking, reversing, and maneuvering safely. Therefore, it is necessary to understand how people use them to do so effectively and efficiently. This paper describes an experimental setup to observe the driver’s behavior while reverse parking the car with and without the use of a camera as well as to observe the impact of glare during daylight on the driving performance. An area of 14 meters x 12 meters is designed as the Test Environment (TE) to fit in two parking spaces. Three cameras are used to monitor the participant’s head movements and eye movements. This research is designed to study and collect driver behavior data including the reaction time taken during parking concerning the driver with different age groups, camera usage during a sunny day, and also two different parking conditions which are parallel parking and perpendicular parking. This setup is expected to be implemented to forecast the camera usage among the drivers to help the driver park their car in the reverse direction to solve the limited blind spot issue. Collected data from this study will be used as the preliminary data for road test evaluation. It is to further study the impact of glare during daylight on driving performance
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