Incentivizing Exploration with Heterogeneous Value of Money

Recently, Frazier et al. proposed a natural model for crowdsourced exploration of different a priori unknown options: a principal is interested in the long-term welfare of a population of agents who arrive one by one in a multi-armed bandit setting. However, each agent is myopic, so in order to incentivize him to explore options with better long-term prospects, the principal must offer the agent money. Frazier et al. showed that a simple class of policies called time-expanded are optimal in the worst case, and characterized their budget-reward tradeoff. The previous work assumed that all agents are equally and uniformly susceptible to financial incentives. In reality, agents may have different utility for money. We therefore extend the model of Frazier et al. to allow agents that have heterogeneous and non-linear utilities for money. The principal is informed of the agent's tradeoff via a signal that could be more or less informative. Our main result is to show that a convex program can be used to derive a signal-dependent time-expanded policy which achieves the best possible Lagrangian reward in the worst case. The worst-case guarantee is matched by so-called "Diamonds in the Rough" instances; the proof that the guarantees match is based on showing that two different convex programs have the same optimal solution for these specific instances. These results also extend to the budgeted case as in Frazier et al. We also show that the optimal policy is monotone with respect to information, i.e., the approximation ratio of the optimal policy improves as the signals become more informative.Comment: WINE 201

A New Differential Evolution with self-terminating ability using fuzzy control and k-nearest neighbors

A new Differential Evolution (DE) that incorporates fuzzy control and k-nearest neighbors algorithm to determine the terminating condition is proposed. A technique called Iteration Windows is introduced to govern the number of iteration in each searching stage. The size of the iteration windows is controlled by a fuzzy controller, which uses the information provided by the k-nearest neighbors system to analyze the population during the searching process. The controller keeps controlling the iteration windows until the end of the searching process. The wavelet based mutation process is embedded in the DE searching process to enhance the searching performance of DE. The F weight of DE is also controlled by the fuzzy controller to further speed up the searching process. A suite of benchmark test functions is employed to evaluate the performance of the proposed method. It is shown empirically that the proposed method can terminate the searching process with a reasonable number of iteration. © 2010 IEEE

Efficacy of selective laser trabeculoplasty for normal tension glaucoma: 1 year results

BACKGROUND: Normal tension glaucoma (NTG) is commonly treated with anti-glaucoma medications. Recently, selective laser trabeculoplasty (SLT) has been demonstrated to lower the intraocular pressure (IOP) and medication use in NTG. The purpose of this study was to investigate the efficacy of a single session of SLT for NTG at 1 year. METHODS: This prospective cohort study recruited NTG patients taking anti-glaucoma medication. Potential subjects were excluded if they had had previous glaucoma surgery or laser and also if intraocular surgery or additional SLT procedures were performed after the first treatment. All subjects underwent a 1-month washout. A 30% IOP reduction was set as the target IOP. A single session of SLT was performed to 360 degrees of the trabecular meshwork. At 1-month after SLT, medication was resumed to achieve the target IOP. The IOP was measured every 3 months, and the number of medications was recorded at 3, 6, and 12 months. Only the right eye was used for statistical analysis. RESULTS: In 41 right eyes, the mean pre-study IOP was 14.3 +/- 3.4 mmHg while on 1.5 +/- 0.8 eye drops. The post-washout IOP was 16.2 +/- 2.2 mmHg. A mean of 191.1 +/- 26.3 SLT shots at 1.0 +/- 0.07 mJ were applied. There was significant IOP reduction at all time intervals following SLT when compared to the post-washout IOP (P < 0.0001). The number of medications was significantly reduced at all time intervals following SLT when compared to the pre-study level (P < 0.0001). At 12 months, the mean IOP was 12.2 +/- 2.2 mmHg while on 1.1 +/- 0.9 eye drops. CONCLUSIONS: A single session of SLT for NTG achieved an additional 15% IOP reduction while using 27% less medication at 1 year compared to pre-study levels.Trial registration: The Clinical Trials Register of the University of Hong Kong HKCTR1847The European Clinical Trials Database 2014-003305-15 (August 11, 2014) (https://eudract.ema.europa.eu/).published_or_final_versio

MRI detection of peritoneal adhesion with dialysate enhancement

This study investigated the use of clinical peritoneal dialysis fluid (dialysate) as a peritoneal contrast agent to visualize peritoneal adhesions in rats at 7 Tesla. Intraperitoneal injection of dialysate (~0.1 mL/g) allowed the MR detection of peritoneal adhesions that were surgically induced in all rats studied (N = 6). MR measurements of adhesion surface areas correlated well with the postmortem estimations (R = 0.99). T1 and T2 values of undiluted dialysate were found to be 3017.5¡Ó35.3 ms and 108.4¡Ó2.0 ms, respectively. These findings demonstrated dialysate-enhanced MRI as a potentially valuable technique in clinical detection and evaluation of post-surgical peritoneal adhesion and to monitor therapeutic interventions (i.e., against peritoneal adhesion) in future preclinical research.published_or_final_versio

Systematic Review and Meta-Analysis of Brief Cognitive Instruments to Evaluate Suspected Dementia in Chinese-Speaking Populations

Background: Chinese is the most commonly spoken world language; however, most cognitive tests were developed and validated in the West. It is essential to find out which tests are valid and practical in Chinese speaking people with suspected dementia. Objective: We therefore conducted a systematic review and meta-Analysis of brief cognitive tests adapted for Chinese-speaking populations in people presenting for assessment of suspected dementia. Methods: We searched electronic databases for studies reporting brief (≤20 minutes) cognitive test's sensitivity and specificity as part of dementia diagnosis for Chinese-speaking populations in clinical settings. We assessed quality using Centre for Evidence Based Medicine (CEBM) criteria and translation and cultural adaptation using the Manchester Translation Reporting Questionnaire (MTRQ), and Manchester Cultural Adaptation Reporting Questionnaire (MCAR). We assessed heterogeneity and combined sensitivity in meta-Analyses. Results: 38 studies met inclusion criteria and 22 were included in meta-Analyses. None met the highest CEBM criteria. Five studies met the highest criteria of MTRQ and MCAR. In meta-Analyses of studies with acceptable heterogeneity (I2 <  75%), Addenbrooke's Cognitive Examination Revised III (ACE-R ACE-III) had the best sensitivity and specificity; specifically, for dementia (93.5% 85.6%) and mild cognitive impairment (81.4% 76.7%). Conclusions: Current evidence is that the ACE-R and ACE-III are the best brief cognitive assessments for dementia and mild cognitive impairment in Chinese-speaking populations. They may improve time taken to diagnosis, allowing people to access interventions and future planning

How early can myocardial iron overload occur in Beta thalassemia major?

BACKGROUND: Myocardial siderosis is the most common cause of death in patients with beta thalassemia major(TM). This study aimed at investigating the occurrence, prevalence and severity of cardiac iron overload in a young Chinese population with beta TM. METHODS AND RESULTS: We analyzed T2* cardiac magnetic resonance (CMR), left ventricular ejection fraction (LVEF) and serum ferritin (SF) in 201 beta TM patients. The median age was 9 years old. Patients received an average of 13 units of blood per year. The median SF level was 4536 ng/ml and 165 patients (82.1%) had SF>2500 ng/ml. Myocardial iron overload was detected in 68 patients (33.8%) and severe myocardial iron overload was detected in 26 patients (12.6%). Twenty-two patients ≤10 years old had myocardial iron overload, three of whom were only 6 years old. No myocardial iron overload was detected under the age of 6 years. Median LVEF was 64% (measured by CMR in 175 patients). Five of 6 patients with a LVEF<56% and 8 of 10 patients with cardiac disease had myocardial iron overload. CONCLUSIONS: The TM patients under follow-up at this regional centre in China patients are younger than other reported cohorts, more poorly-chelated, and have a high burden of iron overload. Myocardial siderosis occurred in patients younger than previously reported, and was strongly associated with impaired LVEF and cardiac disease. For such poorly-chelated TM patients, our data shows that the first assessment of cardiac T2* should be performed as early as 6 years old

An effective theory for jet propagation in dense QCD matter: jet broadening and medium-induced bremsstrahlung

Two effects, jet broadening and gluon bremsstrahlung induced by the propagation of a highly energetic quark in dense QCD matter, are reconsidered from effective theory point of view. We modify the standard Soft Collinear Effective Theory (SCET) Lagrangian to include Glauber modes, which are needed to implement the interactions between the medium and the collinear fields. We derive the Feynman rules for this Lagrangian and show that it is invariant under soft and collinear gauge transformations. We find that the newly constructed theory SCET$_{\rm G}$ recovers exactly the general result for the transverse momentum broadening of jets. In the limit where the radiated gluons are significantly less energetic than the parent quark, we obtain a jet energy-loss kernel identical to the one discussed in the reaction operator approach to parton propagation in matter. In the framework of SCET$_{\rm G}$ we present results for the fully-differential bremsstrahlung spectrum for both the incoherent and the Landau-Pomeranchunk-Migdal suppressed regimes beyond the soft-gluon approximation. Gauge invariance of the physics results is demonstrated explicitly by performing the calculations in both the light-cone and covariant $R_{\xi}$ gauges. We also show how the process-dependent medium-induced radiative corrections factorize from the jet production cross section on the example of the quark jets considered here.Comment: 52 pages, 15 pdf figures, as published in JHE

Parton Distributions for Event Generators

In this paper, conventional Global QCD analysis is generalized to produce parton distributions optimized for use with event generators at the LHC. This optimization is accomplished by combining the constraints due to existing hard-scattering experimental data with those from anticipated cross sections for key representative SM processes at LHC (by the best available theory) as joint input to the global analyses. The PDFs obtained in these new type of global analyses using matrix elements calculated in any given order will be best suited to work with event generators of that order, for predictions at the LHC. This is most useful for LO event generators at present. Results obtained from a few candidate PDF sets (labeled as CT09MCS, CT09MC1 and CT09MC2) for LO event generators produced in this way are compared with those from other approaches.Comment: 35 pages, 19 figures, and 4 table

The fate of steroid estrogens: Partitioning during wastewater treatment and onto river sediments

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2010 Springer Science+Business Media B.V.The partitioning of steroid estrogens in wastewater treatment and receiving waters is likely to influence their discharge to, and persistence in, the environment. This study investigated the partitioning behaviour of steroid estrogens in both laboratory and field studies. Partitioning onto activated sludge from laboratory-scale Husmann units was rapid with equilibrium achieved after 1 h. Sorption isotherms and Kd values decreased in the order 17α-ethinyl estradiol > 17α-estradiol > estrone > estriol without a sorption limit being achieved (1/n >1). Samples from a wastewater treatment works indicated no accumulation of steroid estrogens in solids from primary or secondary biological treatment, however, a range of steroid estrogens were identified in sediment samples from the River Thames. This would indicate that partitioning in the environment may play a role in the long-term fate of estrogens, with an indication that they will be recalcitrant in anaerobic conditions.EPSR

Clinical correlation of nuclear survivin in esophageal squamous cell carcinoma

To examine the correlation of survivin (both total and nuclear survivin) with clinicopathological parameters of esophageal squamous cell carcinoma (ESCC) patients. Tumors and non-tumor tissues near the proximal resection margins were resected from ESCC patients undergone esophagectomy. Quantitative polymerase chain reaction (qPCR) was performed to detect survivin mRNA expression level in the 10 paired tumor and adjacent non-tumor tissues. To confirm with the clinical situation, survivin mRNA and protein expression were measured by qPCR and immunoblot, respectively, in 5 ESCC cell lines and a non-neoplastic esophageal epithelial cell line. Immunohistochemistry was employed to reveal the cellular localization of survivin in tumor tissues isolated from the 64 ESCC patients undergone surgery alone. Up-regulation of survivin mRNA and protein was found in 5 ESCC lines (HKESC-1, HKESC-2, HKESC-3, HKESC-4, and SLMT-1) when compared to a non-neoplastic esophageal epithelial cell line NE-1. In particular, HKESC-3, HKESC-4, and SLMT-1 cells demonstrated ~50-fold increase in survivin mRNA. High level of survivin mRNA in tumor tissues when compared to non-tumor tissues was found in 70 % (7 of 10) of clinical cases. The increase in expression ranged from ~twofold to ~16-fold. Immunohistochemistry results showed that survivin was found at the cell nuclei in all specimens examined. Nuclear expression of survivin was inversely associated with the likelihood of developing nodal metastasis (p = 0.021) and significantly associated with early-stage ESCC (p = 0.039). Nuclear survivin could serve as a marker for indicating disease status in ESCC patients. © 2012 The Author(s).published_or_final_versio