Numerical Solution of Piecewise Constant Delay Systems Based on a Hybrid Framework

An efficient numerical scheme for solving delay differential equations with a piecewise constant delay function is developed in this paper. The proposed approach is based on a hybrid of block-pulse functions and Taylor’s polynomials. The operational matrix of delay corresponding to the proposed hybrid functions is introduced. The sparsity of this matrix significantly reduces the computation time and memory requirement. The operational matrices of integration, delay, and product are employed to transform the problem under consideration into a system of algebraic equations. It is shown that the developed approach is also applicable to a special class of nonlinear piecewise constant delay differential equations. Several numerical experiments are examined to verify the validity and applicability of the presented technique

Biological and reproduction behaviour of Eleuthronema tetradactylum

In this study spawning season, brood stocks live place and biological behaviour of Eleutheronema tetradactylum (rashgoo) was identified in the coastal waters of Bushehr province, Persian Gulf from July. 2005 to Sep. 2006. During this time fish samples were collected by the gillnet or set net. With the mesh size of 9 and 25 Cm. A total of 93 fishes were examined in the fishery Research Centre laboratory, Standard length, total weight, gonad and hepatic weight were measured and histological studies on gonads were conducted in this period. Gonadosomatic index was calculated in the different seasons we showed significant differences between research seasons (P<0.05) the Maximum GSI was in winter and spring with (1-1/2 %) and minimum was in summer and autumn (/15-/22 %). In histological study of ovary had observed five stages in sections: IMMATURE, INITIAL MATURATION, ADVANCED MATURATION, MATURED and SPAWNED. And testicular tissues were showed three stages of the sperm development: Spermatogonia, Spermatocytes and Spermatides or sperm. This study had showed that Higher quantities of brood stock were caught in DAYER region of Bushehr province. The stomach contents observed that small fishes, shrimp and crab were feed by the caught fishes, it means that Eleutheronema tetradactylum (rashgoo).is a carnivorous fish. The results were obtained from this research showed that reproductive season in Four finger thread fine (Eleutheronema tetradactylum) (rashgoo) in the coastal waters of Bushehr was in the could seasons

One-loop Vilkovisky-DeWitt Counterterms for 2D Gravity plus Scalar Field Theory

The divergent part of the one-loop off-shell effective action is computed for a single scalar field coupled to the Ricci curvature of 2D gravity ($c \phi R$), and self interacting by an arbitrary potential term $V(\phi)$. The Vilkovisky-DeWitt effective action is used to compute gauge-fixing independent results. In our background field/covariant gauge we find that the Liouville theory is finite on shell. Off-shell, we find a large class of renormalizable potentials which include the Liouville potential. We also find that for backgrounds satisfying $R=0$, the Liouville theory is finite off shell, as well.Comment: 19 pages, OKHEP 92-00

MCP-1 Upregulates Amylin Expression in Murine Pancreatic β Cells through ERK/JNK-AP1 and NF-κB Related Signaling Pathways Independent of CCR2

BACKGROUND: Amylin is the most abundant component of islet amyloid implicated in the development of type 2 diabetes. Plasma amylin levels are elevated in individuals with obesity and insulin resistance. Monocyte chemoattractant protein-1 (MCP-1, CCL2) is involved in insulin resistance of obesity and type 2 diabetes. We investigated the effect of MCP-1 on amylin expression and the underlying mechanisms with murine pancreatic β-cell line MIN6 and pancreatic islets. METHODOLOGY/PRINCIPAL FINDINGS: We found that MCP-1 induced amylin expression at transcriptional level and increased proamylin and intermediate forms of amylin at protein level in MIN6 cells and islets. However, MCP-1 had no effect on the expressions of proinsulin 1 and 2, as well as prohormone convertase (PC) 1/3 and PC2, suggesting that MCP-1 specifically induces amylin expression in β-cells. Mechanistic studies showed that although there is no detectable CCR2 mRNA in MIN6 cells and islets, pretreatment of MIN6 cells with pertussis toxin inhibited MCP-1 induced amylin expression, suggesting that alternative Gi-coupled receptor(s) mediates the inductive effect of MCP-1. MCP-1 rapidly induced ERK1/2 and JNK phosphorylation. Inhibitors for MEK1/2 (PD98059), JNK (SP600125) or AP1 (curcumin) significantly inhibited MCP-1-induced amylin mRNA expression. MCP-1 failed to induce amylin expression in pancreatic islets isolated from Fos knockout mice. EMSA showed that JNK and ERK1/2 were involved in MCP-1-induced AP1 activation. These results suggest that MCP-1 induces murine amylin expression through AP1 activation mediated by ERK1/2 or JNK. Further studies showed that treatment of MIN6 cells with NF-κB inhibitor or overexpression of IκBα dominant-negative construct in MIN6 cells significantly inhibited MCP-1-induced amylin expression, suggesting that NF-κB related signaling also participates in MCP-1-induced murine amylin expression. CONCLUSIONS/SIGNIFICANCE: MCP-1 induces amylin expression through ERK1/2/JNK-AP1 and NF-κB related signaling pathways independent of CCR2. Amylin upregulation by MCP-1 may contribute to elevation of plasma amylin in obesity and insulin resistance

Direct bandgap GeSn alloys for laser application

Efforts towards development of monolithically integrated silicon-compatible lasers have been revitalized since the demonstration of optically pumped GeSn waveguide lasers. Here we investigate the laser emission of GeSn alloys by means of waveguide and microdisk photoluminescence

Islamic legal methodologies and Shariah screening standards: application in the Indonesian stock market

This article provides a framework for applying the principles of Islamic legal methodology to determine the optimal Shariah screening standards for Islamic equity markets. It is argued that using maslahah mursalah (unrestricted benefit) is an appropriate method for identifying appropriate financial standards and its principles stipulate that the benchmark that yields the best economic returns to investors should be chosen. The methodological framework is applied to the Indonesia equity market where the economic implications of the Islamic stock screening standards of the Indonesian Islamic Shariah Stock Index and four global indices are assessed. Portfolios are constructed by applying Islamic stock screening standards for each of the indices by using data on 377 stocks listed in the Indonesian stock market for 5 years. The performances measured by the Sharpe ratio, Treynor index, and Jensen alpha reveal that the Dow Jones Islamic Index screening criteria performs the best. Based on the method of maslahah mursalah, the article recommends using the screening standard of this index in the Indonesian stock market to maximize benefits to investors. While the approach used in this article is applied to Islamic equity markets, the methodological framework can also be used for other similar cases in Islamic finance

Cerebellar Zones: A Personal History

Cerebellar zones were there, of course, before anyone noticed them. Their history is that of young people, unhindered by preconceived ideas, who followed up their observations with available or new techniques. In the 1960s of the last century, the circumstances were fortunate because three groups, in Leiden, Lund, and Bristol, using different approaches, stumbled on the same zonal pattern in the cerebellum of the cat. In Leiden, the Häggqvist myelin stain divulged the compartments in the cerebellar white matter that channel the afferent and efferent connections of the zones. In Lund, the spino-olivocerebellar pathways activated from individual spinal funiculi revealed the zonal pattern. In Bristol, charting the axon reflex of olivocerebellar climbing fibers on the surface of the cerebellum resulted in a very similar zonal map. The history of the zones is one of accidents and purposeful pursuit. The technicians, librarians, animal caretakers, students, secretaries, and medical illustrators who made it possible remain unnamed, but their contributions certainly should be acknowledged

Allergenicity assessment of genetically modified crops—what makes sense?

GM crops have great potential to improve food quality, increase harvest yields and decrease dependency on certain chemical pesticides. Before entering the market their safety needs to be scrutinized. This includes a detailed analysis of allergenic risks, as the safety of allergic consumers has high priority. However, not all tests currently being applied to assessing allergenicity have a sound scientific basis. Recent events with transgenic crops reveal the fallacy of applying such tests to GM crops

ROCK Inhibitor Is Not Required for Embryoid Body Formation from Singularized Human Embryonic Stem Cells

We report a technology to form human embryoid bodies (hEBs) from singularized human embryonic stem cells (hESCs) without the use of the p160 rho-associated coiled-coil kinase inhibitor (ROCKi) or centrifugation (spin). hEB formation was tested under four conditions: +ROCKi/+spin, +ROCKi/-spin, -ROCKi/+spin, and -ROCKi/-spin. Cell suspensions of BG01V/hOG and H9 hESC lines were pipetted into non-adherent hydrogel substrates containing defined microwell arrays. hEBs of consistent size and spherical geometry can be formed in each of the four conditions, including the -ROCKi/-spin condition. The hEBs formed under the -ROCKi/-spin condition differentiated to develop the three embryonic germ layers and tissues derived from each of the germ layers. This simplified hEB production technique offers homogeneity in hEB size and shape to support synchronous differentiation, elimination of the ROCKi xeno-factor and rate-limiting centrifugation treatment, and low-cost scalability, which will directly support automated, large-scale production of hEBs and hESC-derived cells needed for clinical, research, or therapeutic applications