4,285 research outputs found
Gauge-Invariant Formulation of Spin-Current-Density Functional Theory
Spin-currents and non-abelian gauge potentials in electronic systems can be
treated by spin-current-density functional theory, whose main input is the
exchange-correlation (xc) energy expressed as a functional of spin-currents.
Constructing a functional of spin currents that is invariant under
U(1)SU(2) transformations is a long-standing challenge. We solve the
problem by expressing the energy as a functional of a new variable we call
"invariant vorticity". As an illustration we construct the xc energy functional
for a two-dimensional electron gas with linear spin-orbit coupling and show
that it is proportional to the fourth power of the spin current.Comment: 8 pages, 3 figures, submitte
B(E2) value of even-even 108-112Pd isotopes by interacting boson model-1*
This work studies the systematic reduced transition probabilities B(E2),
intrinsic quadrupole moments and deformation parameters of Pd isotopes with
even neutrons from N= 62 to 66. The downward reduced transition probabilities
B(E2) from gamma transition 8+ to 6+, 6+ to 4+, 4+ to 2+ and 2+ to 0+ states of
even-even 108-112Pd isotopes were calculated by the Interacting Boson Model
(IBM-1) and compared with the available previous experimental results. The
ratio of the excitation energies of the first 4+ and the first 2+ excited
states, R4/2, is also studied for the classification of symmetry of these
nuclei. Furthermore we have studied systematically the transition rate R of
some of the low-lying quadrupole collective states in comparison with the
available experimental data. The associated quadrupole moments and deformation
parameters have been calculated. The results of this calculation are in good
agreement with the corresponding available experimental data. The 108-112Pd
isotopes show the O(6) symmetry
Energy-momentum Density of Gravitational Waves
In this paper, we elaborate the problem of energy-momentum in general
relativity by energy-momentum prescriptions theory. Our aim is to calculate
energy and momentum densities for the general form of gravitational waves. In
this connection, we have extended the previous works by using the prescriptions
of Bergmann and Tolman. It is shown that they are finite and reasonable. In
addition, using Tolman prescription, exactly, leads to same results that have
been obtained by Einstein and Papapetrou prescriptions.Comment: LaTeX, 9 pages, 1 table: added reference
Optimization of the Agar-gel Method for Isolation of Migrating Ascaris suum Larvae From the Liver and Lungs of Pigs
Experiments on use of an agar-gel method for recovery of migrating Ascaris suum larvae from the liver and lungs of pigs were conducted to obtain fast standardized methods. Subsamples of blended tissues of pig liver and lungs were mixed with agar to a final concentration of 1% agar and the larvae allowed to migrate out of the agar-gel into 0.9% NaCl at 38°C. The results showed that within 3 h more than 88% of the recoverable larvae migrated out of the liver agar-gel and more than 83% of the obtained larvae migrated out of the lung agar-gel. The larvae were subsequently available in a very clean suspension which reduced the sample counting time. Blending the liver for 60 sec in a commercial blender showed significantly higher larvae recovery than blending for 30 sec. Addition of gentamycin to reduce bacterial growth during incubation, glucose to increase larval motility during migration or ice to increase sedimentation of migrated larvae did not influence larvae recovery significantly
Enhanced Heartbeat Graph for emerging event detection on Twitter using time series networks
© 2019 Elsevier Ltd With increasing popularity of social media, Twitter has become one of the leading platforms to report events in real-time. Detecting events from Twitter stream requires complex techniques. Event-related trending topics consist of a group of words which successfully detect and identify events. Event detection techniques must be scalable and robust, so that they can deal with the huge volume and noise associated with social media. Existing event detection methods mostly rely on burstiness, mainly the frequency of words and their co-occurrences. However, burstiness sometimes dominates other relevant details in the data which could be equally significant. Besides, the topological and temporal relationships in the data are often ignored. In this work, we propose a novel graph-based approach, called the Enhanced Heartbeat Graph (EHG), which detects events efficiently. EHG suppresses dominating topics in the subsequent data stream, after their first detection. Experimental results on three real-world datasets (i.e., Football Association Challenge Cup Final, Super Tuesday, and the US Election 2012) show superior performance of the proposed approach in comparison to the state-of-the-art techniques
Characterization of the Adherence of Clostridium difficile Spores: The Integrity of the Outermost Layer Affects Adherence Properties of Spores of the Epidemic Strain R20291 to Components of the Intestinal Mucosa
Indexación: Web of Science.Clostridium difficile is the causative agent of the most frequently reported nosocomial diarrhea worldwide. The high incidence of recurrent infection is the main clinical challenge of C. difficile infections (CBI). Formation of C. difficile spores of the epidemic strain R20291 has been shown to be essential for recurrent infection and transmission of the disease in a mouse model. However, the underlying mechanisms of how these spores persist in the colonic environment remains unclear. In this work, we characterized the adherence properties of epidemic R20291 spores to components of the intestinal mucosa, and we assessed the role of the exosporium integrity in the adherence properties by using cdeC mutant spores with a defective exosporium layer. Our results showed that spores and vegetative cells of the epidemic R20291 strain adhered at high levels to monolayers of Caco-2 cells and mucin. Transmission electron micrographs of Caco-2 cells demonstrated that the hair-like projections on the surface of R20291 spores are in close proximity with the plasma membrane and microvilli of undifferentiated and differentiated monolayers of Caco-2 cells. Competitive-binding assay in differentiated Caco-2 cells suggests that spore-adherence is mediated by specific binding sites. By using spores of a cdeC mutant we demonstrated that the integrity of the exosporium layer determines the affinity of adherence of C. difficile spores to Caco-2 cells and mucin. Binding of fibronectin and vitronectin to the spore surface was concentration-dependent, and depending on the concentration, spore-adherence to Caco-2 cells was enhanced. In the presence of an aberrantly-assembled exosporium (cdeC spores), binding of fibronectin, but not vitronectin, was increased. Notably, independent of the exosporium integrity, only a fraction of the spores had fibronectin and vitronectin molecules binding to their surface. Collectively, these results demonstrate that the integrity of the exosporium layer of strain R20291 contributes to selective spore adherence to components of the intestinal mucosa.http://journal.frontiersin.org/article/10.3389/fcimb.2016.00099/ful
Exposition of Discriminatory Variables in a Family of Hypertensive and Non hypertensive Diabetic Patients: A Case Study of Komfo Anokye Teaching Hospital – Kumasi, Ghana
This study sought to expose variable(s) capable of predicting hypertensive status of diabetic patients. To this end, data on 260 diabetic patients at the Komfo Anokye Teaching Hospital’s Diabetic Centre in Ghana were collected using data extraction form. The majority (144) of the 260 diabetic patients representing about 55% were also hypertensive as against 116 (45%) who were not hypertensive. Frequency analysis also revealed female dominance as far as the two diagnoses (Diabetes with hypertension and diabetes without hypertension) were concerned. However, the percentage of females in diabetes with hypertension (77%) was greater than the percentage of females in diabetes without hypertension (67%). The minimum age of hypertensive diabetic patients was 30 years as against 11 years for those diagnosed as non-hypertensive diabetic. A discriminant analysis was adopted to expose the discriminatory variables as far as the two diagnoses were concerned. The study indicated a strong association between diagnosis (diabetes with hypertension and diabetes without hypertension) and body mass index (BMI), and to some extent, also between diagnosis and age. BMI and age were identified as principal discriminating variables for separating patients diagnosed with diabetes with hypertension from those with diabetes without hypertension. The index of discrimination (canonical correlation) associated with the resulting discriminant model was 0.42 (42%). This is good since it is greater than 30. The hit ratio, (or the percentage of cases correctly classified) is 0.654 or 65.4%. Also, leave-one-out cross-validation which was used instead of an independent holdout sample correctly classified 64.2% of the cases. Finally, it was concluded that ageing and extra BMI gained are risk factors for diabetic patients to develop hypertension. Therefore, the model was good for prediction. Keywords: Diabetes, Hypertension, Model, Discriminant Analysis, Ghan
- …