A mixed finite element method for fourth order elliptic equations with variable coefficients

AbstractA new mixed finite element method for the Dirichlet problem of fourth order elliptic equations with variable coefficients on convex polygonal domain has been developed in this paper, the biharmonic problem and bending problems of elastic plates being particular cases of the general problem considered in the paper. For bending problems, this method gives a simultaneous approximation to the displacement u and the ‘actual’ bending and twisting moment (ψij (i,j = 1, 2). Error estimate for the mixed finite element solution has been given

Enzymatic Trans-esterification of Phospholipids to Aceto-phospholipid: A Good Surface Active Emulsifier and the Role of Phospholipid in Drug Delivery System

Aceto-phospholipids were prepared enzymatically by incorporating the acetate group at sn-1 or sn-2 position with out acetylating the amine group of phospholipids. There are a sharp change in surface properties after acetylation. At the same time the emulsifying properties of aceto-phospholipids is also remarkable than original soy phospholipids. We have got the separate droplet size distribution pattern of water in oil type of emulsion in presence of different aceto phospholipids compare to original soy phospholipids. The emulsification properties of newly prepared aceto-phospholipids were explained from the HLB values. The biological activities of the aceto-phospholipid were also highlighted here using some reported articles

Radio Frequency Seeker Modelling and Seeker Filter Design

Radio frequency seeker model, including receiver angle error noise modelling and filtering of noise from seeker measurement, is presented in this paper. The effects of eclipsing, radar cross section fluctuation, etc on seeker sight-line rate measurement are highlighted. The formulation for colour noise modelling of sight-line rate noise is derived based on the knowledge of seeker receiver angle error noise model. Two Kalman filter configurations for filtering of noise from seeker output have been considered in this paper, based on sight-line rate kinematics and noise characteristic. It has been  observed from the simulation studies that sight-line rate signal varies slowly at higher interceptor-target ranges; with severe colour noise in sight line rate measurement, and therefore higher weightage for noise attenuation is beneficial in Kalman filter configuration. So, kinematic plus state augmentation for colour noise are considered for adequate filtering for higher interceptor-target ranges. Whereas for lower interceptor-target ranges, sight-line rate changes appreciably, which have been tracked by a simplified/modified spherical coordinate model, which uses knowledge of interceptor-target  engagement dynamics. For both the filters, benefits of colour noise modelling and process model augmentation through coloured noise states, for filtering severe colour noise of seeker, has been demonstrated

Vitamin D receptor expression levels determine the severity and complexity of disease progression among leprosy reaction patients

AbstractWe studied the roles of vitamin D and its receptor, VDR, in the progression of leprosy. The majority of individuals with leprosy from Kolkata, India, with a type 1 or type 2 reaction have low levels of vitamin D3 in serum samples. Interestingly, individuals with a type 2 reaction associated with neuritis/erythema nodosum leprosum had very low VDR mRNA expression levels, ranging from 5% to 10%, compared to that of healthy control subjects; these patients also had a high bacilli index, ranging from 3+ to 5+. This is the first report to indicate that VDR expression levels may determine the complexity and severity of the progression of leprosy

Fluid dynamics of R-charged black holes

We construct electrically charged AdS_5 black hole solutions whose charge, mass and boost-parameters vary slowly with the space-time coordinates. From the perspective of the dual theory, these are equivalent to hydrodynamic configurations with varying chemical potential, temperature and velocity fields. We compute the boundary theory transport coefficients associated with a derivative expansion of the energy momentum tensor and R-charge current up to second order. In particular, we find a first order transport coefficient associated with the axial component of the current.Comment: 31 pages, v2: published version; added some references, discussion of the charge-current changed, results unchanged, v3: typo in formula (15) changed, v4: added footnote 3 in order to clarify the relation of our results to those of arXiv:0809.259

Phase transitions in neutron star and magnetars and their connection with high energetic bursts in astrophysics

The phase transition from normal hadronic matter to quark matter in neutron stars (NS) could give rise to several interesting phenomena. Compact stars can have such exotic states up to their surface (called strange stars (SS)) or they can have quark core surrounded by hadronic matter, known as hybrid stars (HS). As the state of matter of the resultant SS/HS is different from the initial hadronic matter, their masses also differ. Therefore, such conversion leads to huge energy release, sometimes of the order of $10^{53}$ ergs. In the present work we study the qualitative energy released by such conversion. Recent observations reveal huge surface magnetic field in certain stars, termed magnetars. Such huge magnetic fields can modify the equations of state (EOS) of the matter describing the star. Therefore, the mass of magnetars are different from normal NS. The energy released during the conversion process from neutron magnetar (NM) to strange magnetar/hybrid magnetar (SS/HS) is different from normal NS to SS/HS conversion. In this work we calculate the energy release during the phase transition in magnetars. The energy released during NS to SS/HS conversion exceeds the energy released during NM to SM/HM conversion. The energy released during the conversion of NS to SS is always of the order of $10^{53}$ ergs. The amount of energy released during such conversion can only be compared to the energy observed during the gamma ray bursts (GRB). The energy liberated during NM to HM conversion is few times lesser, and is not likely to power GRB at cosmological distances. However, the magnetars are more likely to lose their energy from the magnetic poles and can produce giant flares, which are usually associated with magnetars.Comment: 14 pages, 4 figures, 4 table

Black strings in AdS_5

We present non-extremal magnetic black string solutions in five-dimensional gauged supergravity. The conformal infinity is the product of time and S^1xS_h, where S_h denotes a compact Riemann surface of genus h. The construction is based on both analytical and numerical techniques. We compute the holographic stress tensor, the Euclidean action and the conserved charges of the solutions and show that the latter satisfy a Smarr-type formula. The phase structure is determined in the canonical ensemble, and it is shown that there is a first order phase transition from small to large black strings, which disappears above a certain critical magnetic charge that is obtained numerically. For another particular value of the magnetic charge, that corresponds to a twisting of the dual super Yang-Mills theory, the conformal anomalies coming from the background curvature and those arising from the coupling to external gauge fields exactly cancel. We also obtain supersymmetric solutions describing waves propagating on extremal BPS magnetic black strings, and show that they possess a Siklos-Virasoro reparametrization invariance.Comment: 40 pages, 7 figures, JHEP3. v2: minor corrections, 2 references added. v3: typos in holographic stress tensor corrected, 3 references adde

Soil biochemistry and microbial activity in vineyards under conventional and organic management at Northeast Brazil.

The São Francisco Submedium Valley is located at the Brazilian semiarid region and is an important center for irrigated fruit growing. This region is responsible for 97% of the national exportation of table grapes, including seedless grapes. Based on the fact that orgThe São Francisco Submedium Valley is located at the Brazilian semiarid region and is an important center for irrigated fruit growing. This region is responsible for 97% of the national exportation of table grapes, including seedless grapes. Based on the fact that organic fertilization can improve soil quality, we compared the effects of conventional and organic soil management on microbial activity and mycorrhization of seedless grape crops. We measured glomerospores number, most probable number (MPN) of propagules, richness of arbuscular mycorrhizal fungi (AMF) species, AMF root colonization, EE-BRSP production, carbon microbial biomass (C-MB), microbial respiration, fluorescein diacetate hydrolytic activity (FDA) and metabolic coefficient (qCO2). The organic management led to an increase in all variables with the exception of EE-BRSP and qCO2. Mycorrhizal colonization increased from 4.7% in conventional crops to 15.9% in organic crops. Spore number ranged from 4.1 to 12.4 per 50 g-1 soil in both management systems. The most probable number of AMF propagules increased from 79 cm-3 soil in the conventional system to 110 cm-3 soil in the organic system. Microbial carbon, CO2 emission, and FDA activity were increased by 100 to 200% in the organic crop. Thirteen species of AMF were identified, the majority in the organic cultivation system. Acaulospora excavata, Entrophospora infrequens, Glomus sp.3 and Scutellospora sp. were found only in the organically managed crop. S. gregaria was found only in the conventional crop. Organically managed vineyards increased mycorrhization and general soil microbial activity

Big GABA II: Water-referenced edited MR spectroscopy at 25 research sites

Accurate and reliable quantification of brain metabolites measured in vivo using 1H magnetic resonance spectroscopy (MRS) is a topic of continued interest. Aside from differences in the basic approach to quantification, the quantification of metabolite data acquired at different sites and on different platforms poses an additional methodological challenge. In this study, spectrally edited γ-aminobutyric acid (GABA) MRS data were analyzed and GABA levels were quantified relative to an internal tissue water reference. Data from 284 volunteers scanned across 25 research sites were collected using GABA+ (GABA + co-edited macromolecules (MM)) and MM-suppressed GABA editing. The unsuppressed water signal from the volume of interest was acquired for concentration referencing. Whole-brain T1-weighted structural images were acquired and segmented to determine gray matter, white matter and cerebrospinal fluid voxel tissue fractions. Water-referenced GABA measurements were fully corrected for tissue-dependent signal relaxation and water visibility effects. The cohort-wide coefficient of variation was 17% for the GABA + data and 29% for the MM-suppressed GABA data. The mean within-site coefficient of variation was 10% for the GABA + data and 19% for the MM-suppressed GABA data. Vendor differences contributed 53% to the total variance in the GABA + data, while the remaining variance was attributed to site- (11%) and participant-level (36%) effects. For the MM-suppressed data, 54% of the variance was attributed to site differences, while the remaining 46% was attributed to participant differences. Results from an exploratory analysis suggested that the vendor differences were related to the unsuppressed water signal acquisition. Discounting the observed vendor-specific effects, water-referenced GABA measurements exhibit similar levels of variance to creatine-referenced GABA measurements. It is concluded that quantification using internal tissue water referencing is a viable and reliable method for the quantification of in vivo GABA levels