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

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

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

Orthopedic management of spina bifida. Part I: hip, knee, and rotational deformities

Abstract Children with spina bifida develop a wide variety of congenital and acquired orthopedic deformities. Among these are hip deformities such as contracture, subluxation, or dislocation. Patients may also have problems with the knee joint, such as knee flexion or extension contracture, knee valgus deformity, or late knee instability and pain. In addition, rotational deformities of the lower extremities, either internal or external torsion, are common as well. This paper will review both the overall orthopedic care of a patient with spina bifida and provide a focused review of the diagnosis and management of the above deformities. In addition, this paper will review the incidence, etiology, classification, and prognosis of spina bifida. The use of gait analysis and orthoses will be covered as well. The forthcoming Part II will cover foot and ankle deformities in spina bifida

Chemical weed management effects on productivity and profitability of gladiolus (Gladiolus hybridus) in north-western Indo-Gangetic Plains

A field experiment, involving ten weed control treatments laid out in a randomized complete block design with three replications, was undertaken at the Indian Agricultural Research Institute, New Delhi during the winter seasons, 2011-12 and 2012-13. The objective was to evaluate the effects of different combinations of herbicides, particularly pre-emergence tank-mix herbicides applications on weeds, and flowering, corm yield and benefit-cost economics of gladiolus (Gladiolus hybridus Hort.). It was observed that all herbicidal treatments resulted in significantly lower density of monocot and dicot weeds, and total weed dry weight compared to weedy check, which had the highest two- year mean density of monocot (165/m2) and dicot (364/m2) weeds and total weed dry weight (171 g/m2). Among herbicide treatments, atrazine 1.0 kg/ha pre-emergence followed by rice residue @ 5 tonnes/ha at 2 days after atrazine application caused the greatest reduction in density and dry weight of weeds. All herbicidal treatments, except butachlor 1.0 kg/ha pre-emergence, were equally effective as this treatment against weeds. The herbicides and their doses adopted in this study did not pose any phytotoxicity to gladiolus plants. The tank-mix pre-emergence applications were usually more effective than the single herbicide application. The tank-mix pre-emergence application of pendimethalin 0.75 kg/ha + metribuzin 0.3 kg/ha resulted in significantly greater two-year mean gladiolus plant height (116 cm), cut-flower yield (172 500 spikes/ha), corm yield (3.82 tonnes/ha) and net returns (` 243 100/ha) compared to weedy check and most other treatments, and was most remunerative

Identification of a Rare Coding Variant in Complement 3 Associated with Age-related Macular Degeneration

Macular degeneration is a common cause of blindness in the elderly. To identify rare coding variants associated with a large increase in risk of age-related macular degeneration (AMD), we sequenced 2,335 cases and 789 controls in 10 candidate loci (57 genes). To increase power, we augmented our control set with ancestry-matched exome sequenced controls. An analysis of coding variation in 2,268 AMD cases and 2,268 ancestry matched controls revealed two large-effect rare variants; previously described R1210C in the CFH gene (fcase = 0.51%, fcontrol = 0.02%, OR = 23.11), and newly identified K155Q in the C3 gene (fcase = 1.06%, fcontrol = 0.39%, OR = 2.68). The variants suggest decreased inhibition of C3 by Factor H, resulting in increased activation of the alternative complement pathway, as a key component of disease biology