Performance analysis under dynamic loading of wavelength continuous and non‐continuous WDM networks with shortest‐path routing

The performance of WDM networks using shortest path routing is studied under wavelength continuous (WC) and non‐continuous (NWC) constraints and dynamic traffic loading. Approximate analytical models are presented for the performance studies of such systems. Results of numerical calculations based on these models and simulations are given for different network topologies for the purposes of comparison. These analytical and simulation results are used to study the performance of these WDM networks under dynamic traffic loading. Copyright © 2001 John Wiley & Sons, Ltd.     

Psychiatric disorders associated with risk for the development of eating disorders during adolescence and early adulthood.

Longitudinal data were used to investigate whether anxiety, depressive, disruptive, personality, or substance use disorders are associated with risk for the development of eating disorders during adolescence or early adulthood. Psychiatric disorders were assessed among 726 youths from a random community sample during adolescence and early adulthood. Depressive disorders during early adolescence were associated with elevated risk for the onset of eating disorders, dietary restriction, purging behavior, and recurrent weight fluctuations after preexisting eating problems and other psychiatric disorders were controlled statistically. Disruptive and personality disorders were independently associated with elevated risk for specific eating or weight problems. The present findings suggest that depressive disorders during early adolescence may contribute to the development of eating disorders during middle adolescence or early adulthood. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence for compliance controlled oxygen vacancy and metal filament based resistive switching mechanisms in RRAM

We present electrical evidence on asymmetric metal-insulator-semiconductor (MIS) based test structures in support of the presence of two different independent switching mechanisms in a resistive random access memory (RRAM) device. The valid mechanism for switching depends on the compliance capping (I_gl) for forming/SET transition. Our results convincingly show that low compliance based switching only involves reversible oxygen ion drift to and from oxygen gettering gate electrodes, while high compliance switching involves formation and rupture of conductive metallic nanofilaments, as verified further by our physical analysis investigations. We have observed this unique dual mode switching mechanism only in NiSi-based gate electrodes, which have a moderate oxygen solubility as well as relatively low melting point.     

Advancing understanding using Nonaka’s model of knowledge creation and problem-based learning

Nonaka’s model of knowledge creation can provide guidance for designing learning environments and activities. However, Bereiter is critical of the model because it does not address whether understanding is deepened in the process of socialization, externalization, combination and internalization. To address this issue of understanding, this paper proposed a framework that synthesizes the basic phases of problem-based learning with Nonaka’s model. This paper reports on a study investigating if a course designed based on this authentic framework can help to stimulate knowledge creation based on deepening understanding. Several types of data were collected in this design-based research, namely: reflections by the participants and instructor; group discussions; student-created artifacts; and documents, records and artifacts that reflect the overall design of the course. The findings suggest that the participants demonstrated advancing understanding amidst knowledge creating conditions and processes consistent with Nonaka’s model. Other key implications are also discussed.     

Comparison of a radioallergosorbent (RAST) inhibition method and a monoclonal enzyme linked immunosorbent assay (ELISA) for aeroallergen measurement

BACKGROUND: Mouse and rat urinary proteins are potent occupational allergens for exposed personnel. Methods of measuring airborne allergens differ greatly, and reported levels of allergens vary considerably between laboratories. OBJECTIVES: To compare the values obtained using two different methods of allergen detection. METHODS: Air samples were collected in rat rooms in Sweden and the United Kingdom at 2 L/min on to polytetrafluoroethylene (PTFE) filters and extracted in buffer containing 0.5% v/v Tween 20. Airborne rat urinary allergen (RUA) was measured in all samples by both RAST inhibition using a polyclonal human serum pool (UK) and a two monoclonal antibody sandwich ELISA employing antibodies specific for Rat n 1.02 (alpha2u-globulin) (Sweden). RESULTS: The two methods gave values which were correlated (r2 log values = 0.72, P<0.0001), but differed by several orders of magnitude (median [range] ratio of RAST inhibition/ELISA = 316 [7-26(80)]. There was a systematic bias: as the absolute values increased, the difference in the measurements increased. The rat urine standards used were antigenically similar. CONCLUSIONS: A large contrast in RUA values obtained from the two assays was observed in this study. This may be primarily due to methodological differences, but variations in antibody specificities or composition of allergenic epitopes in the air samples may contribute. The results demonstrate that standardization of methods and antibodies is necessary before interlaboratory comparisons can be made.     

Proof of stability conditions for token passing rings by Lyapunovfunctions

A token passing ring can be described as a system of M queues with one server that rotates around the queues sequentially. Georgiadis-Szpankowski (1992) considered rings where the token (server) performs x ∇ l_j services on queue j, where x is the size of queue j upon arrival of the token, and l_j is a fixed limit of service for queue j. The token then spends some random time switching to the next queue. For j=1, ..., M, arrivals to queue j are Poisson with rate λ_j, and service times have mean s _j and are independent of the arrival and switchover processes. The purpose of this paper is to give an alternate and simpler proof of the stability conditions given by Georgiadis-Szpankowski using Lyapunov functions. An additional assumption is made about the second moments of the service and switchover times being finite     

Investigation of intrinsic dielectric breakdown mechanism in Cu/low-/spl kappa/ interconnect system

Using a specifically designed test structure applying human body model electrostatic discharge (ESD) stress, the origin of dielectric breakdown in Cu/low-/spl kappa/ interconnect systems was found to be in interfacial delamination. The interfacial delamination between a SiC capping layer and a SiOC interdielectric layer is responsible for the increase of intermetal dielectric leakage current, causing high current Joule heating as well as catastrophic thermal breakdown. Also, the defect density increased as the delamination becomes wider while the number of ESD zaps increases.     

Obsessive-compulsive disorder limited to pregnancy

Two patients with fulminant amebic colitis with colon perforation and concomitant liver abscess were collected over the last 5 years. One patient underwent emergency laparotomy to treat amebic cecal perforation. Diverted ileostomy saved his life. The ileostomy was successfully reversed 6 months later. The other patient underwent 4 laparotomies with more invasive procedures in less than 1 month due to sequential complications of amebiasis. Colon resection with enterostomy miraculously allowed him to survive. In comparison with the latter, who underwent more aggressive surgery and experienced more catastrophic complications, the former with conservative surgery had a smoother clinical result. Thus, conservative operation for colon perforation due to amebiasis is recommended. Besides, thanks to the alertness of doctors, the favorable age of the patients, the advent of new antiamebic and antimicrobial agents, excellent hyperalimentation, the great improvement in medical facilities and postoperative care, the two critical patients eventually survived after several operations, and had a better outcome as compared with the high mortality rate of 87.5% in our hospital 2 decades earlier.     

Monitoring of TiSi2 formation on narrow polycrystallinesilicon lines using Raman spectroscopy

Micro-Raman spectroscopy is used to monitor titanium silicide (TiSi₂) formation on narrow undoped polycrystalline silicon lines. Linewidths varying from 1.0 μm down to 0.35 μm, with silicidation by rapid thermal anneal (RTA) temperature ranging between 780°C and 1020°C were analyzed. Phase changes between C49 and C54-TiSi₂ phases were clearly observed. Results demonstrate that analysis of the C54-TiSi₂ Raman peak intensity allowed fast and nondestructive estimation of the process window for low resistivity C54-TiSi₂ formation. Comparison with sheet resistivity measurements showed that micro-Raman scattering provides a complimentary means to electrical analysis for the study of TiSi₂ formation     

Carotenoids and retinoids in human nutrition.

Since the discovery of vitamin A as a fat-soluble growth factor in the early part of the century, research into carotenoids and retinoids has attracted the attention of many scientists. These two groups of compounds are still being actively studied all over the world since many gaps in knowledge exist and new frontiers are being pursued. Recent developments in studies into the possible roles of carotenoids and retinoids beyond their classical functions in vision have created a great deal of excitement in the biomedical community. This review covers a wide range of topics pertaining to these two closely related compounds. Particular emphasis is given to the functions of these compounds and their roles in human nutrition. Various aspects of vitamin A deficiency and studies on carotenoids and retinoids in cancer development and prevention are reviewed in some detail.