Reduction of Coincident Photomultiplier Noise Relevant to Astroparticle Physics Experiment

In low background and low threshold particle astrophysics experiments using observation of Cherenkov or scintillation light it is common to use pairs or arrays of photomultipliers operated in coincidence. In such circumstances, for instance in dark matter and neutrino experiments, unexpected PMT noise events have been observed, probably arising from generation of light from one PMT being detected by one or more other PMTs. We describe here experimental investigation of such coincident noise events and development of new techniques to remove them using novel pulse shape discrimination procedures. When applied to data from a low background NaI detector with facing PMTs the new procedures are found to improve noise rejection by a factor of 20 over conventional techniques, with significantly reduced loss of signal events.Comment: Submitted to NIM

Multi-technique characterisation of MOVPE-grown GaAs on Si

The heterogeneous integration of III-V materials on a Si CMOS platform offers tremendous prospects for future high speed and low power logic applications. That said this integration generates immense scientific and technological challenges. In this work multi-technique characterisation is used to investigate properties of GaAs layers grown by Metal-Organic Vapour Phase Epitaxy (MOVPE) on Si substrates - (100) with 4⁰ offset towards - under various growth conditions. This being a crucial first step towards the production of III-V template layers with a relatively lower density of defects for selective epitaxial overgrowth of device quality material. The optical and structural properties of heteroepitaxial GaAs are first investigated by micro-Raman spectroscopy and photoluminescence and reflectance measurements. High-resolution X-ray diffraction (HR-XRD) is used to investigate structural properties. Advanced XRD techniques, including double-axis diffraction and X-ray crystallographic mapping are used to evaluate degrees of relaxation and distribution of the grain orientations in the epilayers, respectively. Results obtained from the different methodologies are compared in an attempt to understand growth kinetics of the materials system. The GaAs overlayer grown with annealing at 735⁰C following As predeposition at 500⁰C shows the best crystallinity. Close inspection confirms the growth of epitaxial GaAs preferentially oriented along (100) embedded in a highly-textured polycrystalline structure

Proteome-wide profiling of the MCF10AT breast cancer progression model

10.1371/journal.pone.0011030PLoS ONE56

An Observation on the Effect of Semi-Elemental Oral Nutritional Supplements on the Reduction of Small Bowel Ostomy Output

Semi-elemental oral nutritional supplements are also referred to the oligomeric, hydrolysed or peptide formula, the nitrogen source of the formulas derived from hydrolyzed oligopeptide of shorter lengths such as the dipeptides and tripeptides. The ingredient of casein and lactaalbumin hydrolysates in this formula are believed to be capable of stimulating the jejunal absorption of water and electrolytes. The postulated stimulation of improves absorption increased our curiosity on its effect on those patient with high output ostomy. We understand that this formula is more costly compared to the other polymeric formula available in the market. We would like to share an observation of two ostomies output that are managed conservatively along with the supplementation of a semi-elemental formula. We retrospectively review the case notes of two patients with small bowel ostomies and graphs were plotted to demonstrate the relationship between the output and the intake of the semi-elemental formula. We observed an interesting pattern of the ostomy output in relationship to intake volume. The ostomy output decreases as the patients increase the intake of the semi-elemental formula. From our observation, we concluded that semi-elemental formula improved clinical nutrition outcome and also quality of life in terms of stoma output reduction, making the stoma care more manageable. However, we hope that through our observation case studies, we would encourage more researchers to conduct a larger prospective and clinical study to explore the true clinical effects and also cost-effectiveness of this formula

Obturator hernia: A rare condition with common surgical symptoms

Hernia is a common surgical problem. However, worldwide incidence of obturator hernia is <1% of all hernia cases, occurring more commonly in thin, elderly and multiparous female. An 82 years old lady presented with bowel obstruction sign and symptoms for 4 days duration. Imaging study, computed tomography with enhanced contrast (CECT) of abdomen and pelvis showed small bowel obstruction secondary to left obturator hernia. Emergency abdominal exploration with left transverse transperitoneal approach was performed. Intraoperatively, anti mesenteric part of ileal wall was incarcerated through the left obturator foramen causing small bowel obstruction and it was resected with end to end anastomosis. She recovered well and was discharged on postoperative day 7. The signs and symptoms of obturator hernia are non-specific. Most cases are presented with symptoms of intestinal obstruction, resulting in diagnostic difficulty for this rare condition. Delay in diagnosis and surgical intervention contribute to poorer outcomes

G-Brownian Motion as Rough Paths and Differential Equations Driven by G-Brownian Motion

The present paper is devoted to the study of sample paths of G-Brownian motion and stochastic differential equations (SDEs) driven by G-Brownian motion from the view of rough path theory. As the starting point, we show that quasi-surely, sample paths of G-Brownian motion can be enhanced to the second level in a canonical way so that they become geometric rough paths of roughness 2 < p < 3. This result enables us to introduce the notion of rough differential equations (RDEs) driven by G-Brownian motion in the pathwise sense under the general framework of rough paths. Next we establish the fundamental relation between SDEs and RDEs driven by G-Brownian motion. As an application, we introduce the notion of SDEs on a differentiable manifold driven by GBrownian motion and construct solutions from the RDE point of view by using pathwise localization technique. This is the starting point of introducing G-Brownian motion on a Riemannian manifold, based on the idea of Eells-Elworthy-Malliavin. The last part of this paper is devoted to such construction for a wide and interesting class of G-functions whose invariant group is the orthogonal group. We also develop the Euler-Maruyama approximation for SDEs driven by G-Brownian motion of independent interest

Self-Evolving Data Cloud-Based PID-Like Controller for Nonlinear Uncertain Systems

In this article, a novel self-evolving data cloud-based proportional integral derivative (PID) (SEDCPID) like controller is proposed for uncertain nonlinear systems. The proposed SEDCPID controller is constructed by using fuzzy rules with nonparametric data cloud-based antecedence and PID-like consequence. The antecedent data clouds adopt the relative data density to represent the fuzzy firing strength of input variables instead of the explicit design of the membership functions in the classical sense. The proposed SEDCPID controller has the advantages of evolving structure and adapting parameter concurrently in an online manner. The density and distance information of data clouds are proposed to achieve the addition and deletion of data clouds and also a stable recursive method is proposed to update the parameters of the PID-like subcontrollers for the fast convergence performance. Based on the Lyapunov stability theory, the stability of the proposed controller is proven and the proof shows the tracking errors converge to a small neighborhood. Numerical and experimental results illustrate the effectiveness of the proposed controller in handling the uncertain nonlinear dynamic systems

Chimeric Gαq mutants harboring the last five carboxy-terminal residues of Gαi2 or Gαo are resistant to pertussis toxin-catalyzed ADP-ribosylation

AbstractThree widely-used Gαq chimeras harboring the last five residues of Gαi, Gαo and Gαz (qi5, qo5 and qz5) were examined for their ability to serve as substrates for pertussis toxin (PTX)-catalyzed ADP-ribosylation. In COS-7 cells coexpressing one of the three opioid receptors (μ, δ, and κ) and a Gαq chimera, agonist-induced stimulation of phosphoinositide-specific phospholipase C (PI-PLC) was largely insensitive to PTX treatment. Only the qi5-mediated stimulation of PI-PLC by κ-opioids was partially inhibited by PTX. In βγ-release assays, PTX treatment did not affect the ability of opioid receptors to activate these chimeras. [32P]ADP-ribosylation labeled Gαi/o but not qi5 or qo5, although the expression of these chimeras was confirmed by immunodetection. Thus, Gαq chimeras with a Gαi/o-like tail are insensitive to PTX treatment

Vertical Confinement and Evolution of Reentrant Insulating Transition in the Fractional Quantum Hall Regime

We have observed an anomalous shift of the high field reentrant insulating phases in a two-dimensional electron system (2DES) tightly confined within a narrow GaAs/AlGaAs quantum well. Instead of the well-known transitions into the high field insulating states centered around $\nu = 1/5$, the 2DES confined within an 80\AA-wide quantum well exhibits the transition at $\nu = 1/3$. Comparably large quantum lifetime of the 2DES in narrow well discounts the effect of disorder and points to confinement as the primary driving force behind the evolution of the reentrant transition.Comment: 5 pages, 4 figure