Performance Analysis of the Decentralized Eigendecomposition and ESPRIT Algorithm

In this paper, we consider performance analysis of the decentralized power method for the eigendecomposition of the sample covariance matrix based on the averaging consensus protocol. An analytical expression of the second order statistics of the eigenvectors obtained from the decentralized power method which is required for computing the mean square error (MSE) of subspace-based estimators is presented. We show that the decentralized power method is not an asymptotically consistent estimator of the eigenvectors of the true measurement covariance matrix unless the averaging consensus protocol is carried out over an infinitely large number of iterations. Moreover, we introduce the decentralized ESPRIT algorithm which yields fully decentralized direction-of-arrival (DOA) estimates. Based on the performance analysis of the decentralized power method, we derive an analytical expression of the MSE of DOA estimators using the decentralized ESPRIT algorithm. The validity of our asymptotic results is demonstrated by simulations.Comment: 18 pages, 5 figures, submitted for publication in IEEE Transactions on Signal Processin

Trogocytosis by Entamoeba histolytica Mediates Acquisition and Display of Human Cell Membrane Proteins and Evasion of Lysis by Human Serum.

We previously showed that Entamoeba histolytica kills human cells through a mechanism that we termed trogocytosis ("trogo-" means "nibble"), due to its resemblance to trogocytosis in other organisms. In microbial eukaryotes like E. histolytica, trogocytosis is used to kill host cells. In multicellular eukaryotes, trogocytosis is used for cell killing and cell-cell communication in a variety of contexts. Thus, nibbling is an emerging theme in cell-cell interactions both within and between species. When trogocytosis occurs between mammalian immune cells, cell membrane proteins from the nibbled cell are acquired and displayed by the recipient cell. In this study, we tested the hypothesis that through trogocytosis, amoebae acquire and display human cell membrane proteins. We demonstrate that E. histolytica acquires and displays human cell membrane proteins through trogocytosis and that this leads to protection from lysis by human serum. Protection from human serum occurs only after amoebae have undergone trogocytosis of live cells but not phagocytosis of dead cells. Likewise, mutant amoebae defective in phagocytosis, but unaltered in their capacity to perform trogocytosis, are protected from human serum. Our studies are the first to reveal that amoebae can display human cell membrane proteins and suggest that the acquisition and display of membrane proteins is a general feature of trogocytosis. These studies have major implications for interactions between E. histolytica and the immune system and also reveal a novel strategy for immune evasion by a pathogen. Since other microbial eukaryotes use trogocytosis for cell killing, our findings may apply to the pathogenesis of other infections.IMPORTANCE Entamoeba histolytica causes amoebiasis, a potentially fatal diarrheal disease. Abscesses in organs such as the liver can occur when amoebae are able to breach the intestinal wall and travel through the bloodstream to other areas of the body. Therefore, understanding how E. histolytica evades immune detection is of great interest. Here, we demonstrate for the first time that E. histolytica acquires and displays human cell membrane proteins by taking "bites" of human cell material in a process named trogocytosis ("trogo-" means "nibble"), and that this allows amoebae to survive in human serum. Display of acquired proteins through trogocytosis has been previously characterized only in mammalian immune cells. Our study suggests that this is a more general feature of trogocytosis not restricted to immune cells and broadens our knowledge of eukaryotic biology. These findings also reveal a novel strategy for immune evasion by a pathogen and may apply to the pathogenesis of other infections

ARGES: an Expert System for Fault Diagnosis Within Space-Based ECLS Systems

ARGES (Atmospheric Revitalization Group Expert System) is a demonstration prototype expert system for fault management for the Solid Amine, Water Desorbed (SAWD) CO2 removal assembly, associated with the Environmental Control and Life Support (ECLS) System. ARGES monitors and reduces data in real time from either the SAWD controller or a simulation of the SAWD assembly. It can detect gradual degradations or predict failures. This allows graceful shutdown and scheduled maintenance, which reduces crew maintenance overhead. Status and fault information is presented in a user interface that simulates what would be seen by a crewperson. The user interface employs animated color graphics and an object oriented approach to provide detailed status information, fault identification, and explanation of reasoning in a rapidly assimulated manner. In addition, ARGES recommends possible courses of action for predicted and actual faults. ARGES is seen as a forerunner of AI-based fault management systems for manned space systems

The impact of domestic and foreign direct investments on economic growth: evidence from ASEAN countries

In this paper, the dynamic relationships between foreign direct investment (FDI), domestic investment and other determinants of economic growth were examined. Both the short-run and long-run growth processes were modelled using the ARDL approach to carry out cointegration analysis for five ASEAN countries. The main results included (i) domestic investment, FDI, human capital and financial intermediation significantly affected economic growth; (ii) FDI had a positive and significant effect on growth but this was of lesser magnitude as compared to domestic investment; and (iii) a strong support was found for an export-led-growth hypothesis, and the impact of technology transfer from international trade was larger than direct technology transfer from FDI. All in all, our empirical results from the ASEAN countries confirm the view that investments and exports are the engines of growth and it is worthwhile for the authorities to encourage domestic as well as foreign capital to put these countries back on their pre-crisis growth paths

Pile Setup in Cohesive Soil. II: Analytical Quantifications and Design Recommendations

: This paper establishes a methodology to quantify pile setup by using recent field test data that was presented in a companion paper for steel H-piles driven in cohesive soils. Existing methods found in literature for the same purpose either require restrikes of piles onsite or are developed for a specific soil type and seldom use easily quantifiable soil properties, despite their significant influence on pile setup. Following a critical evaluation of the existing methods, a new approach for estimating pile setup was developed using dynamic measurements and analyses in combination with measured soil properties, such as the horizontal coefficient of consolidation, undrained shear strength, and the standard penetration test N value. Using pile setup information available in the literature, the proposed approach has shown that it provides good estimates for the setup of steel H-piles, as well as for other types and sizes of driven piles

Opioid prescribing habits of physicians in Kwara State, Nigeria

Objective: Although opioid analgesics are effective in the treatment of moderate to severe acute, cancer and chronic non-malignant pains, they are under-prescribed in Nigeria. The objective of this study was to assess the prescription pattern of opioids among physicians in a north central State, Nigeria..Design: This was a descriptive cross sectional studySetting: The study was conducted at the International Association for the Study of Pain (IASP)-sponsored workshops on pain and palliative care at the University of Ilorin Teaching Hospital, Ilorin, Nigeria.Participants: These were physicians at the monthly workshops organized by the Pain and Palliative Care Unit of the hospital between August 2011 and July, 2012. Interventions: Pre-tested semi-structured questionnaires were used to obtain responses to questions on pain management including opioids utilization in the various hospitals of the 114 participants.Main outcome measures: The main outcome measure was opioid prescription by the participants.Results: Out of the 114 questionnaires distributed, 113 were returned with complete information giving a response rate of 99.1%. The mean age of the respondents was 42.0±10.8 years. Although 97.3% of the respondents reported that pain was a frequent complaint in their practice, 69.5% of those who reported seeing patients with moderate to severe pain on a daily basis rarely or never prescribed opioid analgesics. The reasons given for poor opioid prescription were fear of respiratory depression (86.8%), fear of addiction (85.1%) and non-availability (28.9%).Conclusion: Opioid prescription rate for patients with moderate-severe pain is low possibly due to myths and misconceptions about their adverse effects.Funding: International Association for the Study of Pain (IASP) Initiative for Improving Pain Education Grant awarded to Dr. K.W. Wahab in 2011.Keywords: Opioid analgesics, prescribing habits, physicians, Nigeri

Exposure to extremely low frequency electromagnetic fields alters the behaviour, physiology and stress protein levels of desert locusts

Electromagnetic fields (EMFs) are present throughout the modern world and are derived from many man-made sources including overhead transmission lines. The risks of extremely-low frequency (ELF) electromagnetic fields are particularly poorly understood especially at high field strengths as they are rarely encountered at ground level. Flying insects, however, can approach close to high field strength transmission lines prompting the question as to how these high levels of exposure affect behaviour and physiology. Here we utilise the accessible nervous system of the locust to ask how exposure to high levels of ELF EMF impact at multiple levels. We show that exposure to ELF EMFs above 4 mT leads to reduced walking. Moreover, intracellular recordings from an identified motor neuron, the fast extensor tibiae motor neuron, show increased spike latency and a broadening of its spike in exposed animals. In addition, hind leg kick force, produced by stimulating the extensor tibiae muscle, was reduced following exposure, while stress-protein levels (Hsp70) increased. Together these results suggest that ELF EMF exposure has the capacity to cause dramatic effects from behaviour to physiology and protein expression, and this study lays the foundation to explore the ecological significance of these effects in other flying insects

Pile Setup in Cohesive Soil. I: Experimental Investigation

Pile setup in cohesive soils has been a known phenomenon for several decades. However, a systematic field investigation to provide the needed data to develop analytical procedures and integrate pile setup into the design method rarely exists. This paper summarizes a recently completed field investigation on five fully instrumented steel H-piles embedded in cohesive soils, while a companion paper discusses the development of the pile setup method. During the field investigation, detailed soil characterization, monitoring of soil total lateral stress and pore-water pressure, collection of pile dynamic restrike data as a function of time, and vertical static load tests were completed. Restrike measurements confirm that pile setup occurs at a logarithmic rate following the end of driving, and its development correlates well with the rate of dissipation of the measured porewater pressure. Based on the field data collected, it was concluded that the skin friction component, not the end bearing, contributes predominantly to the setup, which can be accurately estimated for practical purposes using soil properties, such as coefficient of consolidation, undrained shear strength, and the standard penetration testN-value