Novel Random Forest Methods and Algorithms for Autism Spectrum Disorders Research

Random Forest (RF) is a flexible, easy to use machine learning algorithm that was proposed by Leo Breiman in 2001 for building a predictor ensemble with a set of decision trees that grow in randomly selected subspaces of data. Its superior prediction accuracy has made it the most used algorithms in the machine learning field. In this dissertation, we use the random forest as the main building block for creating a proximity matrix for multivariate matching and diagnostic classification problems that are used for autism research (as an exemplary application). In observational studies, matching is used to optimize the balance between treatment groups. Although many matching algorithms can achieve this goal, in some fields, matching could face its own challenges. Datasets with small sample sizes and limited control reservoirs are prone to this issue. This problem may apply to many ongoing research fields, such as autism spectrum disorder (ASD). We are interested in eliminating the effect of undesirable variables using two types of algorithms, 1:k nearest matching, and full matching. Therefore, we first introduced three different types of 1:k nearest matching algorithms and two full matching based methods to compare group-wise matching vs. pairwise matching for creating an optimal balance and sample size. These proposed methods were applied to a data set from the Brain Development Imaging Lab (BDIL) at San Diego State University. Next, we introduce the iterMatch R package. This package finds a 1:1 matched subsample of the data that is balanced on all matching variables while incorporating missing values in an iterative manner. Missing variables in dataset need to be imputed or only complete cases can be considered in matching. Losing data because of the limitations in a matching algorithm can decrease the power of the study as well as omit important information. Other than introducing the iterMatch package, tuning the input parameters of this package is discussed, using medium and large datasets from the Autism Brain Imaging Data Exchange (ABIDE). We then propose two mixed-effects random forest-based classification algorithms applicable to multi-site (clustered data) using resting-state fMRI (rs-fMRI) and structural MRI (sMRI). These algorithms control the random effects of the confounding factor of the site and fixed-effect of phenotype variable of age internally while building the prediction model. On top of controlling the effects of confounding variables, these algorithms take away the necessity of utilizing a separate dimension reduction algorithm for high dimensional data such as functional connectivity in a non-linear fashion. We show the proposed algorithms can achieve prediction accuracy over 80 percent using test data

Optimal estimation of Dimension-8 Neutral Triple Gauge Couplings at e+e−e^+ e^- Colliders

We investigate the measurement of non-standard ZZV (V = {\gamma}, Z) couplings through Z-boson pair production at the $e^+ e^-$ colliders. We adopt Standard Model Effective Field Theory (SMEFT) approach to study these anomalous neutral triple gauge couplings. There are one CP-conserving and three CP-violating dim-8 SMEFT operators that contribute to ZZV couplings. Using optimal observable technique, the sensitivity of these NP couplings has been estimated and then we compare it with the latest experimental limits on dim-8 couplings at CERN LHC. Effect of beam polarization and correlations among CP-violating ZZV couplings are discussed. Comparison of statistical limits of new physics couplings between optimal observable technique and contemporary cut-based analysis has also been studied in detail.Comment: 17 pages, 7 figures, and 2 table

Inhaler devices: Do patients have a preference and does it make a difference?

The aim of this study was to assess participants perceptions and preferences for inhaler devices; and the relationship of inhaler technique to the decision making process. A mixed-methods approach including a semi-structured interview, Patient Satisfaction and Preference Questionnaire (PASAPQ) and inhalation technique assessment were employed. A total of 25 participants with at least one inhaler were recruited. The interviews analyzed qualitatively. In addition, each participant received a score for PASAPQ in regards to satisfaction with performance, satisfaction with convenience and overall satisfaction. Participants’ inhalation technique was assessed. Two matrices were generated to identify any patterns of association between participants perception from qualitative interviews, with participants satisfaction and preference (PASAPQ) with regards to correct and incorrect use of inhalers. Triangulation of data revealed that there did not appear to be a relationship between patient satisfaction with inhaler device, preference, inhalation technique and level of choice in decision making. There are other factors influencing patient opinions of inhaler devices rather than physical features of inhalers including the level of asthma control, effectiveness of medication in relieving asthma symptoms and length of time of use of inhalers. Participants did not differentiate the device from medication and this affected not only their perception about inhaler devices but also their perception about inhalation technique. This research further highlights the lack of understanding of the relevant role of inhaler devices in asthma management

Inhaler devices: Do patients have a preference and does it make a difference?

The aim of this study was to assess participants perceptions and preferences for inhaler devices; and the relationship of inhaler technique to the decision making process. A mixed-methods approach including a semi-structured interview, Patient Satisfaction and Preference Questionnaire (PASAPQ) and inhalation technique assessment were employed. A total of 25 participants with at least one inhaler were recruited. The interviews analyzed qualitatively. In addition, each participant received a score for PASAPQ in regards to satisfaction with performance, satisfaction with convenience and overall satisfaction. Participants’ inhalation technique was assessed. Two matrices were generated to identify any patterns of association between participants perception from qualitative interviews, with participants satisfaction and preference (PASAPQ) with regards to correct and incorrect use of inhalers. Triangulation of data revealed that there did not appear to be a relationship between patient satisfaction with inhaler device, preference, inhalation technique and level of choice in decision making. There are other factors influencing patient opinions of inhaler devices rather than physical features of inhalers including the level of asthma control, effectiveness of medication in relieving asthma symptoms and length of time of use of inhalers. Participants did not differentiate the device from medication and this affected not only their perception about inhaler devices but also their perception about inhalation technique. This research further highlights the lack of understanding of the relevant role of inhaler devices in asthma management

Probing anomalous Z Z γZ\,Z\,\gamma and Z γ γZ\,\gamma\,\gamma Couplings at the e+ e−e^+\,e^- Colliders using Optimal Observable Technique

We study the anomalous $ZZ\gamma$ and $Z\gamma\gamma$ couplings that can be probed via $Z\gamma$ production at the $e^+ \, e^-$ colliders. We consider Standard Model Effective Field Theory (SMEFT) approach to examine these anomalous neutral triple gauge couplings in a model independent way. There are four independent dimension-8 operators that generate these gauge interactions, one of them is CP-conserving and rest three are CP-violating. We adopt optimal observable technique to extract the sensitivity at which these anomalous couplings can be probed at future linear $e^+e^-$ colliders and then compare the results with the latest experimental limits obtained at the LHC. We also study the impact and advantage of beam polarization in these precision measurements. Limits on individual anomalous couplings as well as the correlation between various couplings have been considered in detail.Comment: 18 pages, 9 figure

The Effect Of Cognitive Load On Economic Decision Making: A Survey And New Experiments

Psychologists and economists have examined the effect of cognitive load in a variety of situations from risk taking to snack choice. We review previous experiments that have directly manipulated cognitive load and summarize their findings. We report the results of two new experiments where participants engage in a digit-memorization task while simultaneously performing a variety of economic tasks including: (1) choices involving risk, (2) choices involving intertemporal substitution, (3) choices with anchoring effects, (4) choices over healthy and unhealthy snacks, and (5) math problems. We find that higher cognitive load reduces numeracy as measured by performance in math problems. Moreover, within-subject analysis indicates that cognitive load leads to more risk-averse behavior, more impatience over money, and (nominally) more likelihood to anchor. We do not find any evidence that cognitive load increases impatience over consumption goods or unhealthy snack choices. Exploiting the panel nature of our data set, we find that those individuals who are most sensitive to cognitive load, as measured by a large drop in their own math performance across 1- and 8-digit memorization treatments, are driving much of the effect

Post-September 11 discourse : the case of Iran in The New York Times.

This study examined how discursive strategies and related linguistic devices were employed by The New York Times (TNYT) to portray Iran after the terrorist attacks in the U.S. on September 11, 2001, and how the media representation may have contributed to negative and/or positive outcomes in terms of geopolitical relations. The study also investigated how sociopolitical assumptions were manifest in producing news about Iran and how the news discourse continued to shape the power relations between the nation and the U.S. in particular, and the world at large. Using Critical Discourse Analysis (CDA) as a multidisciplinary approach, the analysis focused on 171 front-page TNYT news articles from 2001 until 2009. Analysis of the discursive strategies and linguistic means revealed that the news media depicted an overall negative picture of Iran after the September 11 or “9/11” attacks. The effect of this rather stereotypical construction of Iran in TNYT was that of the negative Other, a nation of people that formed part of George W. Bush’s contentious “axis of evil” thesis–malevolent, untrustworthy, violent, and a threat to world peace

A case study of the development of an ESL learner's speaking skills through instructional debate

This study aimed to describe the implementation of debate activities in teaching English to Malaysian secondary students which can enhance students’ speaking skills. Moreover, through observing a Form One student, it was tried to identify the strategies used to compete in classroom debates and to describe the development of the participant’s speaking skills through debates. The study found that debate activities had an impact on the participants through improving collaborative skills, raising awareness of speakers’ roles and guiding participants via prepared texts. Besides, the main communicative strategies employed by the participant were compensatory and avoidance strategies. The result has also shown the improvement of the participant’s speaking skills after five rounds of debate activities

Voicing up in debate competition: oral development of two Malaysian ESL learners

This research used a qualitative approach to focus on the classroom debate between Malaysian English second language learners (ESL). Since debate has been often perceived as not a suitable activity for low proficiency students due to their limited linguistic resources, there has not been much emphasis on the impact of debate on incompetent ESL learners; however, this study was an attempt to concentrate on two students who were not competent in English to investigate their oral development via debate. The study observed the communicative strategies employed in this challenging task during the five debate rounds. Although the progress made was quite limited, the study showed that debate competition can be a relevant and meaningful practice for speaking activity among low proficiency students. Moreover, it showed that debate can be used to scaffold students’ practice in speaking

Quenching a steel plate by water-impinging jets and different simultaneous flow rates

Regarding the great importance of fast cooling in steel industry for the production processes, a deep understanding of heat transfer and fluid dynamics must be held. A steel plate is heated up until a maximum temperature of 700 ⁰C to be then cooled down seconds later by a configuration of multiple impinging water jets. Different flow rates are used simultaneously by different adjacent jets to perform quenching over the sample, so different hardness is obtained in the material over a small area. Temperature drop in time is measured and monitored by embedded thermocouples and LabVIEW program. To achieve greater understanding of the quenching performance with different flow rates, several parameters are selected to be varied in order to achieve the best working conditions. Jet diameter takes values between 4 and 10 mm, initial temperature of quenching varies from 400 to 700 ⁰C, subcooling temperature is tested for 65 and 75 K, and jet velocity varies between 1.9 and 3.9 m/s. The result of total number of 9 experiments shown that variation of jet diameter does not influence substantially on the cooling rate if flow rate is kept constant. High initial quenching temperature (600-700 ⁰C) led to slightly higher cooling rate in the stagnation region of water jets. The peak value of heat transfer rate in the upwash flow zone was more highlighted for initial quenching temperature 600⁰C and below it. Higher values of subcooling and jet velocity produce better cooling rates. The result shown higher jet velocity at one column of water jets changes position of upwash flow slightly toward the adjacent column of jets with lower jet velocity. In general, the result shown that all the studied parameters did not have negative effect on obtaining various cooling rates over the steel plate.<br /