Abundance recovery error analysis using simulated AVIRIS data

Measurement noise and imperfect atmospheric correction translate directly into errors in the determination of the surficial abundance of materials from imaging spectrometer data. The effects of errors on abundance recovery were investigated previously using Monte Carlo simulation methods by Sabol et. al. The drawback of the Monte Carlo approach is that thousands of trials are needed to develop good statistics on the probable error in abundance recovery. This computational burden invariably limits the number of scenarios of interest that can practically be investigated. A more efficient approach is based on covariance analysis. The covariance analysis approach expresses errors in abundance as a function of noise in the spectral measurements and provides a closed form result eliminating the need for multiple trials. Monte Carlo simulation and covariance analysis are used to predict confidence limits for abundance recovery for a scenario which is modeled as being derived from Airborne Visible/Infrared Imaging Spectrometer (AVIRIS)

Local structures of free-standing AlₓGa₁ˍₓN thin films studied by extended x-ray absorption fine structure

Local structural information for the first two atomic shells surrounding Ga atoms in free standing AlₓGa₁ˍₓN alloy films has been obtained by extended x-ray absorption fine structure spectroscopy. For an AlN mole fraction ranging from 0 to 0.6, we found that the first shell Ga–N bond length had only a weak composition dependence, roughly one quarter of that predicted by Vegard’s Law. In the second shell, the Ga–Ga bond length was significantly longer than that of Ga–Al (Δ∼0.04–0.065 Å). A bond-type specific composition dependence was observed for the second shell cation–cation distances. While the composition dependence of the Ga–Ga bond length is ∼70% of that predicted by Vegard’s Law, the Ga–Al bond length was essentially composition independent. These results suggested that local strain in AlₓGa₁ˍₓN was also accommodated by lattice distortion in the Al cation sublattice.This work was supported by the Director, Office of Science, Of- fice of Basic Energy Sciences, Materials Science Division of the U.S. Department of Energy under Contract No. DE-AC03-76SF00098. The LLO work was performed at the UC Berkeley Integrated Materials Laboratory which was supported in part by the National Science Foundation. C.J.G. and M.C.R. were supported by the Australian Synchrotron Research Program, funded by the Commonwealth of Australia via the Major National Research Facilities Program. SSRL was supported by the Office of Basic Energy Sciences of the U.S. Department of Energy

Extended X-ray emission in the IC 2497 - Hanny's Voorwerp system: energy injection in the gas around a fading AGN

We present deep Chandra X-ray observations of the core of IC 2497, the galaxy associated with Hanny's Voorwerp and hosting a fading AGN. We find extended soft X-ray emission from hot gas around the low intrinsic luminosity (unobscured) AGN ($L_{\rm bol} \sim 10^{42}-10^{44}$ erg s$^{-1}$). The temperature structure in the hot gas suggests the presence of a bubble or cavity around the fading AGN (\mbox{E_{\rm bub}} \sim 10^{54} - 10^{55} erg). A possible scenario is that this bubble is inflated by the fading AGN, which after changing accretion state is now in a kinetic mode. Other possibilities are that the bubble has been inflated by the past luminous quasar ($L_{\rm bol} \sim 10^{46}$ erg s$^{-1}$), or that the temperature gradient is an indication of a shock front from a superwind driven by the AGN. We discuss the possible scenarios and the implications for the AGN-host galaxy interaction, as well as an analogy between AGN and X-ray binaries lifecycles. We conclude that the AGN could inject mechanical energy into the host galaxy at the end of its lifecycle, and thus provide a source for mechanical feedback, in a similar way as observed for X-ray binaries.Comment: 9 pages, 5 figures, accepted for publication in MNRA

Circulating Plasma MicroRNAs As Diagnostic Markers for NSCLC

Lung cancer is the most common cause of cancer deaths all over the world, in which non-small cell lung cancer (NSCLC) accounts for ~85% of cases. It is well known that microRNAs (miRNAs) play a critical role in various cellular processes, mediating post-transcriptional silencing either by mRNA degradation through binding the 3' UTR of target mRNA or by translational inhibition of the protein. In the past decade, miRNAs have also been increasingly identified in biological fluids such as human serum or plasma known as circulating or cell-free miRNAs, and may function as non-invasive diagnostic markers for various cancer types including NSCLC. Circulating tumor cells (CTCs) are those cells that are shed from solid tumors and then migrate into the circulation. However, reports concerning the roles of CTCs are quite rare, which may be attributed to the difficulties in the enrichment and detection of CTCs in the circulation. Although, there have been reassuring advances in identifying circulating miRNA-panels, which are assumed to be of diagnostic value in NSCLC early stage, some issues remain concerning the reliability of using miRNA panels as a diagnostic tool for NSCLC. In the current review, we are aiming at providing insights into the miRNAs biology, the mechanisms of miRNAs release into the bloodstream, cell-free miRNAs as the diagnostic markers for NSCLC and the current limitations of CTCs as diagnostic markers in NSCLC.Department of Health Technology and Informatic

The state of the art in integrating machine learning into visual analytics

Visual analytics systems combine machine learning or other analytic techniques with interactive data visualization to promote sensemaking and analytical reasoning. It is through such techniques that people can make sense of large, complex data. While progress has been made, the tactful combination of machine learning and data visualization is still under-explored. This state-of-the-art report presents a summary of the progress that has been made by highlighting and synthesizing select research advances. Further, it presents opportunities and challenges to enhance the synergy between machine learning and visual analytics for impactful future research directions

Implications of MicroRNAs in the treatment of gefitinib-resistant non-small cell lung cancer

2015-2016 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Promoting resilience for HIV prevention in female sex workers in Hong Kong: a randomised controlled trial

Background: Female sex workers are considered a reservoir of HIV and their psychological health has a role to play in HIV infections. In China, commercial sex workers were reported to account for nearly 50% of heterosexual transmission of HIV. Therefore, HIV prevention targeted at mental health could be an innovative strategy in controlling the infection. We aimed to provide an evidence-based resilience-promoting intervention targeting mental health and ultimately safe sexual practices of female sex workers. Methods: This randomised controlled trial was done at three Hong Kong non-governmental organisations, namely Action for REACH OUT, JJJ Association, and the Society of Rehabilitation and Crime Prevention. Participants in this study were women (aged ≥18 years) who had worked as a sex worker in the previous 6 months. We randomly assigned participants to either intervention or usual care (control) according to a predetermined, computer-generated randomisation list. Both group facilitator and partcipants were unmasked to the group allocation, but an independent researcher who was masked to the treatment allocation administered the questionnaires. About half of the participants were permanent residents of Hong Kong whereas the other half were from mainland China. The six-session resilience-promoting intervention was designed to improve the coping skills, self-esteem, and self-efficacy (i.e. the belief of an individuals’ ability to control their actions to achieve desired goal), as measured by Brief-COPE, the Rosenberg Self-esteem Scale, and the Generalised Self- efficacy Scale of female sex workers. Questionnaires were administered by an independent assessor at baseline, post-treatment, and at 3-months follow-up. Participants in the control group received standard service, which included outreach visits, screening for HIV or sexually transmitted infections, and social activities provided by non-governmental organisations. The primary outcome of this study was the resilience scores measured by Connor-Davidson Resilience Scale. We analysed the differences between the two groups using the intention-to-treat analysis. This study was approved by the University of Hong Kong/Hospital Authority Hong Kong West Cluster Internal Review Board (UW 12-220). Verbal informed consent was obtained from all participants. Findings: 127 female sex workers were randomly assigned: 64 joined the control group and 63 joined intervention group. There were significant differences on the score on resilience, self-esteem, and mental health status between groups at post-intervention and 3- month follow-up. We found that condom use in the intervention group at 3-month follow-up was improved compared with the control group. After controlling for marital status and family size, improved resilience scores were associated with intervention group assignment (odds ratio 2∙95 [95% CI 1∙19–7∙35]; p=0∧021) and self-efficacy (1∧13 [1∧03–1∧24]; p=0∧006). Interpretation: Our findings suggest that resilience-promoting intervention programme was effective in improving the mental health status among Chinese female sex workers. This programme is an innovative approach to HIV prevention by promoting both psychological well-being and safe sex for this high-risk population. Funding: Council for the AIDS Trust Fund and General Research Grant, Research Grants Council, HKSAR

Renal screening in children after exposure to low dose melamine in Hong Kong: cross sectional study

Objective To investigate the renal outcomes of children after exposure to low dose melamine in Hong Kong

Gene network exploration of crosstalk between apoptosis and autophagy in chronic myelogenous leukemia

Copyright © 2015 Fengfeng Wang et al. Background. Gene expression levels change to adapt the stress, such as starvation, toxin, and radiation. The changes are signals transmitted through molecular interactions, eventually leading to two cellular fates, apoptosis and autophagy. Due to genetic variations, the signals may not be effectively transmitted to modulate apoptotic and autophagic responses. Such aberrant modulation may lead to carcinogenesis and drug resistance. The balance between apoptosis and autophagy becomes very crucial in coping with the stress. Though there have been evidences illustrating the apoptosis-autophagy interplay, the underlying mechanism and the participation of the regulators including transcription factors (TFs) and microRNAs (miRNAs) remain unclear. Results. Gene network is a graphical illustration for exploring the functional linkages and the potential coordinate regulations of genes. Microarray dataset for the study of chronic myeloid leukemia was obtained from Gene Expression Omnibus. The expression profiles of those genes related to apoptosis and autophagy, including MCL1, BCL2, ATG, beclin-1, BAX, BAK, E2F, cMYC, PI3K, AKT, BAD, and LC3, were extracted from the dataset to construct the gene networks. Conclusion. The network analysis of these genes explored the underlying mechanisms and the roles of TFs and miRNAs for the crosstalk between apoptosis and autophagy.Link_to_subscribed_fulltex

Effect of a 6-month vegan low-carbohydrate (‘Eco-Atkins’) diet on cardiovascular risk factors and body weight in hyperlipidaemic adults: a randomised controlled trial

Objective: Low-carbohydrate diets may be useful for weight loss. Diets high in vegetable proteins and oils may reduce the risk of coronary heart disease. The main objective was to determine the longer term effect of a diet that was both low-carbohydrate and plant-based on weight loss and low-density lipoprotein cholesterol (LDL-C). Design, setting, participants A parallel design study of 39 overweight hyperlipidaemic men and postmenopausal women conducted at a Canadian university-affiliated hospital nutrition research centre from April 2005 to November 2006. Intervention Participants were advised to consume either a low-carbohydrate vegan diet or a high-carbohydrate lacto-ovo vegetarian diet for 6 months after completing 1-month metabolic (all foods provided) versions of these diets. The prescribed macronutrient intakes for the low-carbohydrate and high-carbohydrate diets were: 26% and 58% of energy from carbohydrate, 31% and 16% from protein and 43% and 25% from fat, respectively. Primary outcome Change in body weight. Results: 23 participants (50% test, 68% control) completed the 6-month ad libitum study. The approximate 4 kg weight loss on the metabolic study was increased to −6.9 kg on low-carbohydrate and −5.8 kg on high-carbohydrate 6-month ad libitum treatments (treatment difference (95% CI) −1.1 kg (−2.1 to 0.0), p=0.047). The relative LDL-C and triglyceride reductions were also greater on the low-carbohydrate treatment (treatment difference (95% CI) −0.49 mmol/L (−0.70 to −0.28), p<0.001 and −0.34 mmol/L (−0.57 to −0.11), p=0.005, respectively), as were the total cholesterol:HDL-C and apolipoprotein B:A1 ratios (−0.57 (−0.83, −0.32), p<0.001 and −0.05 (−0.09, −0.02), p=0.003, respectively). Conclusions: A self-selected low-carbohydrate vegan diet, containing increased protein and fat from gluten and soy products, nuts and vegetable oils, had lipid lowering advantages over a high-carbohydrate, low-fat weight loss diet, thus improving heart disease risk factors. Trial Registration clinicaltrials.gov (http://www.clinicaltrials.gov/), #NCT00256516