Performance of Wind Farm Employing Type-4 Wind Turbine with D-Statcom

Wind power is environmentally friendly and cost-predictable nature. It is widely recognized as a promising alternative electric power generation source at a time of uncertain fossil fuel costs and concern over the harmful effects of climate change. Various problems arise due to the rapid injection of wind power in the electrical grid, affecting the power quality. Harmonics and various power quality problems like voltage sag and swell are of common occurrence due to the voltage injected by the wind generators in the electrical grid. These may result into severe problems such as system frequency mismatch and change in power line capability. To reduce such problems a distributed static compensator (DSTATCOM) is employed.  The DSTATCOM is an effective way of reducing power quality problems, removing the wind speed fluctuations and improving the transient stability of wind farm. Simulation results show the proposed effectiveness of wind farm stability and power quality. The generating system is modeled and simulated in MATLAB environment using Simulink and Simpower System toolboxes. Keywords: Wind Farms (WF), Wind Energy, Distributed static compensator (DSTATCOM

Study of thyroid dysfunction and dyslipidemia in chronic kidney diseases

Background: Though there are many studies on thyroid dysfunction and dyslipidemia in Chronic Kidney Disease (CKD), no study is conclusive. Aim of this study was to correlate abnormalities in thyroid function and lipid profile with the severity of renal failure and also to observe the difference of these abnormalities between patients on conservative management verses hemodialysis.Methods: Hundred consecutive CKD cases admitted to Medicine Department were taken up for the study. They were divided into two groups as Group-A [on conservative management] and Group-B [on regular Hemodialysis (HD)]. Hundred healthy persons were taken as control in Group-C. After evaluation of thyroid function and lipid profile statistical analysis was done by students t-test, chi-square and regression analysis.Results: Hundred CKD cases with 74% male (n=74) and 26% female (n=26) in a M: F ratio of 2.9:1 were found to be in different stages CKD (0, 2, 20, 28 and 50 in stage-1 to stage-5 respectively). In 50 cases of stage-5 CKD, 30 were on HD and 20 on conservative management. Diabetes Mellitus (DM) (40%) was the commonest etiology of CKD followed by Hypertension (HTN), obstructive uropathy, chronic glomerulonephritis (CGN) and polycystic kidney disease (PKD). Thyromegaly was not found in a single case. In all CKD cases (Group-A+B) TT3 (TT3) was significantly low (P =0.0011) when compared with control (Group-C) and no difference was found between Group-A and Group-B. Fall in TT3 worsened with increasing severity of CKD. Lipid profile study revealed Decreased High-Density Lipoprotein Cholesterol (HDLc) and increased Triglyceride (TG), Total Cholesterol (TC), Low Density Lipoprotein Cholesterol (LDLc), TC/HDLc and LDLc/HDLc in Group-A than Group-B but only TG and TC increase was statistically significant. The levels of TG and TC and TC/HDLc increased as the stage of CKD progressed and was statistically significant (P= 0.035).Conclusions: There occurs a state of biochemical hypothyroidism without overt clinical hypothyroid state in CKD, the extent of which correlates with the severity of CKD. Increased cardiovascular complications occur due to accelerated atherosclerosis in CKD. This study confirmed that atherogenic lipid profile and thyroid dysfunction worsen with the progression of disease. Difference between patients on conservative management and HD was not found

The Fourth Element: Characteristics, Modelling, and Electromagnetic Theory of the Memristor

In 2008, researchers at HP Labs published a paper in {\it Nature} reporting the realisation of a new basic circuit element that completes the missing link between charge and flux-linkage, which was postulated by Leon Chua in 1971. The HP memristor is based on a nanometer scale TiO$_2$ thin-film, containing a doped region and an undoped region. Further to proposed applications of memristors in artificial biological systems and nonvolatile RAM (NVRAM), they also enable reconfigurable nanoelectronics. Moreover, memristors provide new paradigms in application specific integrated circuits (ASICs) and field programmable gate arrays (FPGAs). A significant reduction in area with an unprecedented memory capacity and device density are the potential advantages of memristors for Integrated Circuits (ICs). This work reviews the memristor and provides mathematical and SPICE models for memristors. Insight into the memristor device is given via recalling the quasi-static expansion of Maxwell's equations. We also review Chua's arguments based on electromagnetic theory.Comment: 28 pages, 14 figures, Accepted as a regular paper - the Proceedings of Royal Society

6,7-Dimethoxy-2,4-diphenylquinoline

In the title structure of the title compound, C23H19NO2, two conformationally similar molecules (A and B) comprise the asymmetric unit. The dihedral angle between phenyl rings bridged by the quinoline moiety are 76.25(8)° in molecule A and 70.39(9)° in molecule B. In the crystal, the independent molecules are connected by C - HO hydrogen bonds and the resulting dimeric aggregates are linked by �-� inter-centroid distance = 3.7370(8)à and C - H� interactions, forming a three-dimensional architecture

MFGE8 does not influence chorio-retinal homeostasis or choroidal neovascularization in vivo

Purpose: Milk fat globule-epidermal growth factor-factor VIII (MFGE8) is necessary for diurnal outer segment phagocytosis and promotes VEGF-dependent neovascularization. The prevalence of two single nucleotide polymorphisms (SNP) in MFGE8 was studied in two exsudative or “wet” Age-related Macular Degeneration (AMD) groups and two corresponding control groups. We studied the effect of MFGE8 deficiency on retinal homeostasis with age and on choroidal neovascularization (CNV) in mice. Methods: The distribution of the SNP (rs4945 and rs1878326) of MFGE8 was analyzed in two groups of patients with “wet” AMD and their age-matched controls from Germany and France. MFGE8-expressing cells were identified in Mfge8+/− mice expressing ß-galactosidase. Aged Mfge8+/− and Mfge8−/− mice were studied by funduscopy, histology, electron microscopy, scanning electron microscopy of vascular corrosion casts of the choroid, and after laser-induced CNV. Results: rs1878326 was associated with AMD in the French and German group. The Mfge8 promoter is highly active in photoreceptors but not in retinal pigment epithelium cells. Mfge8−/− mice did not differ from controls in terms of fundus appearance, photoreceptor cell layers, choroidal architecture or laser-induced CNV. In contrast, the Bruch's membrane (BM) was slightly but significantly thicker in Mfge8−/− mice as compared to controls. Conclusions: Despite a reproducible minor increase of rs1878326 in AMD patients and a very modest increase in BM in Mfge8−/− mice, our data suggests that MFGE8 dysfunction does not play a critical role in the pathogenesis of AMD

Retinal repair by transplantation of photoreceptor precursors

Photoreceptor loss causes irreversible blindness in many retinal diseases. Repair of such damage by cell transplantation is one of the most feasible types of central nervous system repair; photoreceptor degeneration initially leaves the inner retinal circuitry intact and new photoreceptors need only make single, short synaptic connections to contribute to the retinotopic map. So far, brain- and retina-derived stem cells transplanted into adult retina have shown little evidence of being able to integrate into the outer nuclear layer and differentiate into new photoreceptors(1-4). Furthermore, there has been no demonstration that transplanted cells form functional synaptic connections with other neurons in the recipient retina or restore visual function. This might be because the mature mammalian retina lacks the ability to accept and incorporate stem cells or to promote photoreceptor differentiation. We hypothesized that committed progenitor or precursor cells at later ontogenetic stages might have a higher probability of success upon transplantation. Here we show that donor cells can integrate into the adult or degenerating retina if they are taken from the developing retina at a time coincident with the peak of rod genesis(5). These transplanted cells integrate, differentiate into rod photoreceptors, form synaptic connections and improve visual function. Furthermore, we use genetically tagged postmitotic rod precursors expressing the transcription factor Nrl (ref. 6) ( neural retina leucine zipper) to show that successfully integrated rod photoreceptors are derived only from immature post-mitotic rod precursors and not from proliferating progenitor or stem cells. These findings define the ontogenetic stage of donor cells for successful rod photoreceptor transplantation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62596/1/nature05161.pd

Effects of anisotropic interactions on the structure of animal groups

This paper proposes an agent-based model which reproduces different structures of animal groups. The shape and structure of the group is the effect of simple interaction rules among individuals: each animal deploys itself depending on the position of a limited number of close group mates. The proposed model is shown to produce clustered formations, as well as lines and V-like formations. The key factors which trigger the onset of different patterns are argued to be the relative strength of attraction and repulsion forces and, most important, the anisotropy in their application.Comment: 22 pages, 9 figures. Submitted. v1-v4: revised presentation; extended simulations; included technical results. v5: added a few clarification