On the p-adic geometry of traces of singular moduli

The aim of this article is to show that p-adic geometry of modular curves is useful in the study of p-adic properties of traces of singular moduli. In order to do so, we partly answer a question by Ono. As our goal is just to illustrate how p-adic geometry can be used in this context, we focus on a relatively simple case, in the hope that others will try to obtain the strongest and most general results. For example, for p=2, a result stronger than Thm.1 is proved in [Boylan], and a result on some modular curves of genus zero can be found in [Osburn] . It should be easy to apply our method, because of its local nature, to modular curves of arbitrary level, as well as to Shimura curves.Comment: 3 pages, Late

Terahertz Waveguiding in Silicon-Core Fibers

We propose the use of a silicon-core optical fiber for terahertz (THz) waveguide applications. Finite-difference time-domain simulations have been performed based on a cylindrical waveguide with a silicon core and silica cladding. High-resistivity silicon has a flat dispersion over a 0.1 - 3 THz range, making it viable for propagation of tunable narrowband CW THz and possibly broadband picosecond pules of THz radiation. Simulations show the propagation dynamics and the integrated intensity, from which transverse mode profiles and absorption lengths are extraced. It is found that for 140 - 250 micron core diameters the mode is primarily confined to the core, such that the overall absorbance is only slightly less than in bulk polycrystalline silicon.Comment: 6 pages, 3 figures, journal submissio

Colloids out of equilibrium

The fuel-driven assembly of colloids has opened a route to new, biologically inspired active materials

A Model for Transient Oxygen Delivery in Cerebral Cortex

Popular hemodynamic brain imaging methods, such as blood oxygen-level dependent functional magnetic resonance imaging (BOLD fMRI), would benefit from a detailed understanding of the mechanisms by which oxygen is delivered to the cortex in response to brief periods of neural activity. Tissue oxygen responses in visual cortex following brief visual stimulation exhibit rich dynamics, including an early decrease in oxygen concentration, a subsequent large increase in concentration, and substantial late-time oscillations (“ringing”). We introduce a model that explains the full time-course of these observations made by Thompson et al. (2003). The model treats oxygen transport with a set of differential equations that include a combination of flow and diffusion in a three-compartment (intravascular, extravascular, and intracellular) system. Blood flow in this system is modeled using the impulse response of a lumped linear system that includes an inertive element; this provides a simple biophysical mechanism for the ringing. The model system is solved numerically to produce excellent fits to measurements of tissue oxygen. The results give insight into the dynamics of cerebral oxygen transfer, and can serve as the starting point to understand BOLD fMRI measurements

Spinal release of tumour necrosis factor activates c-Jun N-terminal kinase and mediates inflammation-induced hypersensitivity.

BackgroundMounting evidence points to individual contributions of tumour necrosis factor-alpha (TNF) and the c-Jun N-terminal kinase (JNK) pathway to the induction and maintenance of various pain states. Here we explore the role of spinal TNF and JNK in carrageenan-induced hypersensitivity. As links between TNF and JNK have been demonstrated in vitro, we investigated if TNF regulates spinal JNK activity in vivo.MethodsTNF levels in lumbar cerebrospinal fluid (CSF) were measured by enzyme-linked immunosorbent assay, spinal TNF gene expression by real-time polymerase chain reaction and TNF protein expression, JNK and c-Jun phosphorylation by western blotting. The role of spinal TNF and JNK in inflammation-induced mechanical and thermal hypersensitivity was assessed by injecting the TNF inhibitor etanercept and the JNK inhibitors SP600125 and JIP-1 intrathecally (i.t.). TNF-mediated regulation of JNK activity was examined by assessing the effect of i.t. etanercept on inflammation-induced spinal JNK activity.ResultsTNF levels were increased in CSF and spinal cord following carrageenan-induced inflammation. While JNK phosphorylation followed the same temporal pattern as TNF, c-jun was only activated at later time points. Intrathecal injection of TNF and JNK inhibitors attenuated carrageenan-induced mechanical and thermal hypersensitivity. TNF stimulation induced JNK phosphorylation in cultured spinal astrocytes and blocking the spinal actions of TNF in vivo by i.t. injection of etanercept reduced inflammation-induced spinal JNK activity.ConclusionsHere we show that spinal JNK activity is dependent on TNF and that both TNF and the JNK signalling pathways modulate pain-like behaviour induced by peripheral inflammation

SYNOVIAL FLUID AND SERUM ANTIBODIES AGAINST CHLAMYDIA IN DIFFERENT FORMS OF ARTHRITIS: INTRA-ARTICULAR IgA PRODUCTION IN CHLAMYDIA SEXUALLY ACQUIRED REACTIVE ARTHRITIS

SUMMARY Since the presence of Chlamydia has been shown in synovial fluid (SF) from some patients with Chlamydia reactive arthritis, we investigated whether anti-Chlamydia antibodies present in the joint are derived from the circulation or are locally produced. We compared titres of IgG, IgM and IgA antibodies against Chlamydia, and against a control antigen (tetanus toxoid), by an enzyme-linked immunosorbent assay (ELISA), in paired samples of serum and SF from Chlamydia trachomatis sexually acquired reactive arthritis (CT-SARA) patients and from patients with other forms of arthritis. The ratio of serum/SF IgA anti-Chlamydia antibodies was significantly decreased in CT-SARA patients. It is concluded that, in our experimental conditions, we found evidence for intra-articular production of IgA anti-Chlamydia antibodie

THE VALUE OF ISOTYPE DETERMINATION OF SERUM ANTIBODIES AGAINST CHLAMYDIA FOR THE DIAGNOSIS OF CHLAMYDIA REACTIVE ARTHRITIS

SUMMARY In clinical rheumatology, the diagnosis of Chlamydia reactive arthritis is difficult because an incomplete form of the disease can closely resemble an undifferentiated seronegative mono/oligoarthritis. We investigated whether measuring specific isotypes of anti-Chlamydia antibodies in serum can improve the diagnosis, by comparing such antibody concentrations in the serum of patients with well-defined disease, i.e. Chlamydia trachomatis sexually acquired reactive arthritis (CT-SARA), with other arthritides. Antibody levels were determined by enzyme-linked immunosorbent assay (ELISA). When considering two different isotypes and their combination, the best sensitivity (63%) was obtained for IgM and/or IgA results with a specificity of 81%. The patients with CT-SARA and SARA had the highest levels of antibodies of all isotypes tested. It is concluded that, in our experimental conditions, only very high values of specific isotypes could indicate a diagnosis of Chlamydia reactive arthriti

Newspaper commentaries on terrorism in China and Australia: A contrastive genre study

This thesis is a contrastive genre study which explores newspaper commentaries on terrorism in Chinese and Australian newspapers. The study examines the textual patterning of the Australian and Chinese commentaries, interpersonal and intertextual features of the texts as well as considers possible contextual factors which might contribute to the formation of the newspaper commentaries in the two different languages and cultures. For the framework of its analysis, the study draws on systemic functional linguistics, English for Specific Purposes and new rhetoric genre studies, critical discourse analysis, and discussions of the role of the mass media in the two different cultures. The study reveals that Chinese writers often use explanatory rather than argumentative expositions in their newspaper commentaries. They seem to distance themselves from outside sources and seldom indicate endorsement of these sources. Australian writers, on the other hand, predominantly use argumentative expositions to argue their points of view. They integrate and manipulate outside sources in various ways to establish and provide support for the views they express. It is argued that these textual and intertextual practices are closely related to contextual factors, especially the roles of the media and opinion discourse in contemporary China and Australia. The study, by providing both a textual and contextual view of the genre under investigation in the two languages and cultures, aims to establish a framework for contrastive rhetoric research which moves beyond the text into the context of production and interpretation of the texts as a way of exploring reasons for the linguistic and rhetorical choices made in the two sets of texts