Students' Learning Behaviour in Programming Education Analysis: Insights from Entropy and Community Detection.

The high dropout rates in programming courses emphasise the need for monitoring and understanding student engagement, enabling early interventions. This activity can be supported by insights into students' learning behaviours and their relationship with academic performance, derived from student learning log data in learning management systems. However, the high dimensionality of such data, along with their numerous features, pose challenges to their analysis and interpretability. In this study, we introduce entropy-based metrics as a novel manner to represent students' learning behaviours. Employing these metrics, in conjunction with a proven community detection method, we undertake an analysis of learning behaviours across higher- and lower-performing student communities. Furthermore, we examine the impact of the COVID-19 pandemic on these behaviours. The study is grounded in the analysis of empirical data from 391 Software Engineering students over three academic years. Our findings reveal that students in higher-performing communities typically tend to have lower volatility in entropy values and reach stable learning states earlier than their lower-performing counterparts. Importantly, this study provides evidence of the use of entropy as a simple yet insightful metric for educators to monitor study progress, enhance understanding of student engagement, and enable timely interventions.

Analysis of inter-transaction time fluctuations in the cryptocurrency market.

We analyze tick-by-tick data representing major cryptocurrencies traded on some different cryptocurrency trading platforms. We focus on such quantities like the inter-transaction times, the number of transactions in time unit, the traded volume, and volatility. We show that the inter-transaction times show long-range power-law autocorrelations. These lead to multifractality expressed by the right-side asymmetry of the singularity spectra f ( α ) indicating that the periods of increased market activity are characterized by richer multifractality compared to the periods of quiet market. We also show that neither the stretched exponential distribution nor the power-law-tail distribution is able to model universally the cumulative distribution functions of the quantities considered in this work. For each quantity, some data sets can be modeled by the former and some data sets by the latter, while both fail in other cases. An interesting, yet difficult to account for, observation is that parallel data sets from different trading platforms can show disparate statistical properties.

The Cryptocurrency Market in Transition before and after COVID-19: An Opportunity for Investors?

We analyze the correlation between different assets in the cryptocurrency market throughout different phases, specifically bearish and bullish periods. Taking advantage of a fine-grained dataset comprising 34 historical cryptocurrency price time series collected tick-by-tick on the HitBTC exchange, we observe the changes in interactions among these cryptocurrencies from two aspects: time and level of granularity. Moreover, the investment decisions of investors during turbulent times caused by the COVID-19 pandemic are assessed by looking at the cryptocurrency community structure using various community detection algorithms. We found that finer-grain time series describes clearer the correlations between cryptocurrencies. Notably, a noise and trend removal scheme is applied to the original correlations thanks to the theory of random matrices and the concept of Market Component, which has never been considered in existing studies in quantitative finance. To this end, we recognized that investment decisions of cryptocurrency traders vary between bearish and bullish markets. The results of our work can help scholars, especially investors, better understand the operation of the cryptocurrency market, thereby building up an appropriate investment strategy suitable to the prevailing certain economic situation.

Assessing the impact of HIV treatment interruptions using stochastic cellular Automata.

Chronic HIV infection causes a progressive decrease in the ability to maintain homeostasis resulting, after some time, in eventual break down of immune functions. Recent clinical research has shed light on a significant contribution of the lymphatic tissues, where HIV causes accumulation of collagen, (fibrosis). Specifically, where tissue is populated by certain types of functional stromal cells designated Fibroblastic Reticular Cells (FRCs), these have been found to play a crucial role in balancing out apoptosis and regeneration of naïve T-cells through 2-way cellular signaling. Tissue fibrosis not only impedes this signaling, effectively reducing T-cell levels through increased apoptosis of cells of both T- and FRC type but has been found to be irreversible by current HIV standard treatment (cART). While the therapy aims to block the viral lifecycle, cART-associated increase of T-cell levels in blood appears to conceal existing FRC impairment through fibrosis. This hidden impairment can lead to adverse consequences if treatment is interrupted, e.g. due to poor adherence (missing doses) or through periods recovering from drug toxicities. Formal clinical studies on treatment interruption have indicated possible adverse effects, but quantification of those effects in relation to interruption protocol and patient predisposition remains unclear. Accordingly, the impact of treatment interruption on lymphatic tissue structure and T-cell levels is explored here by means of computer simulation. A novel Stochastic Cellular Automata model is proposed, which utilizes all sources of clinical detail available to us (though sparse in part) for model parametrization. Sources are explicitly referenced and conflicting evidence from previous studies explored. The main focus is on (i) spatial aspects of collagen build up, together with (ii) collagen increase after repeated treatment interruptions to explore the dynamics of HIV-induced fibrosis and T-cell loss.

Benign prostatic hyperplasia: racial differences in treatment patterns and prostate cancer prevalence.

OBJECTIVE: • To compare prostate cancer, prostate-related surgery and acute urinary retention rates, as well as associated healthcare resource use over 11 years in African American and Caucasian men with benign prostatic hyperplasia (BPH). PATIENTS AND METHODS: • The BPH-related medical and surgical charges and events were determined for 398 African American men and 1656 Caucasian men followed for a mean of 10.2 years within a health maintenance organization. • Racial differences in clinical outcomes were evaluated using time-to-event analysis, stratifying results by baseline prostate-specific antigen (PSA) values. RESULTS: • Risk of a prostate cancer diagnosis was 2.2 times greater in African American than Caucasian men (95% CI 1.48-3.35, P < 0.001) in analyses adjusting for serum PSA level. • Although African Americans were more likely to receive medical therapy for symptoms of BPH than Caucasians (43.5% vs 37.2%, respectively; P= 0.029), there were no clinically meaningful differences with respect to subsequent acute urinary retention or BPH-related surgery between them, or BPH-related medical charges (US $407 vs US $405 per month). CONCLUSION: • As evidenced by this analysis of 'real-world' clinical practice, African Americans with BPH have a much greater risk of developing prostate cancer than similar Caucasian men highlighting the need for education and early detection in this population.

Comparison of evolutionary algorithms in gene regulatory network model inference.

BACKGROUND: The evolution of high throughput technologies that measure gene expression levels has created a data base for inferring GRNs (a process also known as reverse engineering of GRNs). However, the nature of these data has made this process very difficult. At the moment, several methods of discovering qualitative causal relationships between genes with high accuracy from microarray data exist, but large scale quantitative analysis on real biological datasets cannot be performed, to date, as existing approaches are not suitable for real microarray data which are noisy and insufficient. RESULTS: This paper performs an analysis of several existing evolutionary algorithms for quantitative gene regulatory network modelling. The aim is to present the techniques used and offer a comprehensive comparison of approaches, under a common framework. Algorithms are applied to both synthetic and real gene expression data from DNA microarrays, and ability to reproduce biological behaviour, scalability and robustness to noise are assessed and compared. CONCLUSIONS: Presented is a comparison framework for assessment of evolutionary algorithms, used to infer gene regulatory networks. Promising methods are identified and a platform for development of appropriate model formalisms is established.

Changes in prostate volume in Japanese patients with benign prostatic hyperplasia: association with other urological measures and risk of surgical intervention.

OBJECTIVES: To evaluate changes in prostate volume (PV) and its association with selected urological measures and risk of surgical intervention in Japanese men with benign prostatic hyperplasia (BPH). METHODS: The medical records of all consecutive urologist-diagnosed BPH patients of >or=40 years old who attended any of four urology clinics in Japan during January 2004-June 2006 were reviewed. Both cross-sectional and longitudinal data were captured to analyze baseline correlations among urological measures, to evaluate the longitudinal changes in PV and selected urological measures, and to examine the predictors of surgical intervention. RESULTS: The follow-up period was 2.8 years. Mean PV and mean prostate-specific antigen (PSA) of 1331 eligible patients were 34.0 mL and 4.0 ng/mL, respectively. Both measures increased directly with age. Baseline PV correlated with residual urine volume (r = 0.18, P < 0.05) and PSA (r = 0.41, P < 0.001). Among 319 patients who had more than one PV measurement, PV increased in 51% of patients, remained the same in 28% and decreased in 21%. Use of alpha-blockers at baseline and during follow up was not associated with PV change. Patients who had a PV >or=30 mL, a severe International Prostate Symptom Score and a PSA level >or=1.5 ng/mL at baseline, were more likely to have surgical intervention during the follow-up period. CONCLUSIONS: Predictors generated in this study may help to identify a subset of BPH patients at high risk of surgical intervention.

Quantitative multi-agent models for simulating protein release from PLGA bioerodible nano- and microspheres.

Using poly(lactide-co-glycolide) (PLGA) particles for drug encapsulation and delivery has recently gained considerable popularity for a number of reasons. An advantage in one sense, but a drawback of PLGA use in another, is that drug delivery systems made of this material can provide a wide range of dissolution profiles, due to their internal structure and properties related to particles' manufacture. The advantages of enriching particulate drug design experimentation with computer models, are evident with simulations used to predict and optimize design, as well as indicate choice of best manufacturing parameters. In the present work, we seek to understand the phenomena observed for PLGA micro- and nanospheres, through Cellular Automata (CA) agent-based Monte Carlo (MC) models. Systems are studied both over large temporal scales (capturing slow erosion of PLGA) and for various spatial configurations (capturing initial as well as dynamic morphology). The major strength of this multi-agent approach is to observe dissolution directly, by monitoring the emergent behaviour: the dissolution profile manifested, as a sphere erodes. Different problematic aspects of the modelling process are discussed in details in this paper. The models were tested on experimental data from literature, demonstrating very good performance. Quantitative discussion is provided throughout the text in order to make a demonstration of the use in practice of the proposed model.

[Chronic obstructive pulmonary disease (COPD) burden in Japan--confronting COPD Japan survey].

To grasp the burden and management status of COPD in Japan, a large telephone survey was conducted. In initial screening 400 individuals > or =45 years were identified as either having been given a diagnosis of COPD or fulfilling criteria for their respiratory-related symptoms and smoking history (baseline population) and they were recruited for a detailed investigation (interview sample). They were asked about demographic information, exacerbation, impact of COPD on daily life, and management and treatment. Of the 400 interview samples, 209 subjects (52%) had a diagnosis of COPD, and the remaining 191 ones (48%) were not, retrospectively. It was confirmed that proportions of a current smoker in the COPD (35.4%) and non-COPD (35.6%) groups were almost at the same level. The use of inhaled bronchodilators, recommended by guidelines in 157 treated subjects, was 16% or less, whereas respiratory conditions affected daily activities in 70% of all the subjects. In conclusion, COPD in Japanese subjects significantly affects daily life yet is undiagnosed; there is a need to improve COPD diagnosis and management by general practitioners through disseminating guidelines for diagnosis, management, and prevention of COPD in Japan.

Adverse events from systemic therapies for psoriasis are common in clinical practice.

BACKGROUND: Patients with moderate-to-severe psoriasis frequently require systemic treatment and these medications may be associated with adverse effects. Little is known about the frequency of these events when systemic agents are used in true clinical practice. OBJECTIVE: To determine the frequency of adverse events associated with various systemic psoriasis therapies. METHODS: A retrospective chart review of 753 patients treated in an academic dermatology practice was performed to identify the frequency of adverse events. Poisson regression was used to estimate the odds of significant events for each systemic therapy; UVB-treated patients served as a control population. RESULTS: Methotrexate seemed to be the most prescribed medication. Adverse events were noted with all forms of systemic psoriasis therapy. The highest event rate was seen with oral retinoids, though most of these were considered minor (64%). Cyclosporine had the highest significant adverse event rate (0.9 events/patient). For 'significant' adverse events, oral agents had an adjusted odds ratio>6 compared to standard UVB therapy. The highest risk was for cyclosporine (OR = 20.3); however, the estimate was imprecise (95% confidence interval [4.3, 96.6]). CONCLUSIONS: Traditional psoriasis therapies are associated with significant adverse events in some patients despite toxicity-sparing approaches such as combination therapy. Clinicians need to be aware of screening for adverse events in order to best ensure the safety of their patients and to maximize the efficacy of a given agent. There is still a need for the development of safe and effective treatments for patients with moderate-to-severe psoriasis.

Phenomenological model of bone remodeling cycle containing osteocyte regulation loop.

Biological parameters, such as bone resorption and formation constants, are important variables to achieve optimised hard tissue scaffolds design. To help to understand the modelling process that occurs when a scaffold is implanted it is vital to understand the rather complex bone remodeling process prevalent in native bone. One approach to developing a mathematical model that predicts osteoactivity both in scaffolds, as well as in bone in vivo, is based on a bio-cybernetic vision of basic multicellular unit (BMU) action -. In the case of the model presented in this paper, an additional loop of regulation based on osteocyte activity has been added. This approach has resulted in a four-dimensional system, which shows steady-quasi-cyclic behaviour using a particular range of constants with real biological meaning. The initial findings suggesting that the basic steady-state appears as a torus in multidimensional phase space have been discussed. The existence of this surface in the osteoclasts-osteoblasts-osteocytes-bone subspace indicates that there is a first integral for this dynamic system. Biological and physical interpretation of this integral as a conservative value has been proposed. It is possible to draw an analogy between this conservative value, as a kind of substrate-energy regenerative potential of the bone remodeling system with a molecular nature, to the classical physical value (energy). There are clear indications that there is recovering potential within the BMU that results in a steady operating genetically predominated bone remodeling process. This recovering potential is directed against both mechanical and biomechanical damage to the bone. The current model has credibility when compared to the normal bone remodeling process. However, additional work is required to study a wider range of constants.

Changes in the freezing protocol for human zygotes alter embryonic development and pregnancy rates.

OBJECTIVE: To determine the effect of various freezing protocols on postthaw development and pregnancy rates resulting from transfer of human zygotes. DESIGN: Prospective study. SETTING: Tertiary care center. PATIENT(S): Couples undergoing assisted reproductive technology (ART) procedures who wished to have their excess zygotes cryopreserved. INTERVENTION(S): We cryopreserved zygotes with one of three protocols. MAIN OUTCOME MEASURE(S): Post-thaw survival and development of the zygotes as well as pregnancy rate after transfer of these zygotes. RESULT(S): A 3-minute hold time after seeding, followed by a final preplunging temperature of -180 degrees C, resulted in a clinical pregnancy rate of 28.6%. In contrast, a 15-minute postseed hold time and a -30 degrees C final chamber temperature resulted in a 37.3% clinical pregnancy rate. When we combined the protocols to provide a 15-minute postseed holding time and a -180 degrees C before plunging into liquid nitrogen, we achieved a 69.6% clinical pregnancy rate. CONCLUSION(S): By increasing the postseeding hold time and decreasing the temperature of the freezing chamber before plunging the zygotes into liquid nitrogen, significant improvements can be made in postthaw development and pregnancy rates.

The comorbid state of psoriasis patients in a university dermatology practice.

BACKGROUND: Psoriasis treatment is frequently complicated by the various types and severities of disease as well as the large number of therapies available. Another critical consideration in treatment planning is the presence of comorbid diseases. PURPOSE: The purpose of this study was to evaluate the relative prevalence of major comorbid disease states in patients with psoriasis and to identify significant predictors of these concurrent diseases in such patients. METHODS: A retrospective chart review of 753 patients from an academic dermatology practice was performed. The patients were identified by ICD-9 code for psoriasis in billing records of patients seen between 1997 and 2000. Data on comorbidities were compiled from review of electronic chart notes from all physician visits in the university practice. RESULTS: Comorbid diagnoses were listed in 551 out of 753 (73%) charts. As would be expected, hypertension, dyslipidaemia, diabetes and heart disease were the most common comorbidities; renal failure and hepatitis were least likely. Hepatitis was associated with use of systemic therapies (odds ratio = 2.19) and non-white race. When compared with national prevalence estimates, psoriasis patients had increased heart disease, hypertension, diabetes and emphysema; however, these findings must be interpreted with some caution. CONCLUSIONS: Comorbid diseases are common in psoriasis patients and should be taken into account during treatment planning and surveillance; they may pose unique challenges in caring for patients with psoriasis, particularly those requiring systemic therapy.

Data Integration for Microarrays: Enhanced Inference for Gene Regulatory Networks.

Microarray technologies have been the basis of numerous important findings regarding gene expression in the few last decades. Studies have generated large amounts of data describing various processes, which, due to the existence of public databases, are widely available for further analysis. Given their lower cost and higher maturity compared to newer sequencing technologies, these data continue to be produced, even though data quality has been the subject of some debate. However, given the large volume of data generated, integration can help overcome some issues related, e.g., to noise or reduced time resolution, while providing additional insight on features not directly addressed by sequencing methods. Here, we present an integration test case based on public Drosophila melanogaster datasets (gene expression, binding site affinities, known interactions). Using an evolutionary computation framework, we show how integration can enhance the ability to recover transcriptional gene regulatory networks from these data, as well as indicating which data types are more important for quantitative and qualitative network inference. Our results show a clear improvement in performance when multiple datasets are integrated, indicating that microarray data will remain a valuable and viable resource for some time to come.

Epidemiology and Treatment of New-Onset and Established Rheumatoid Arthritis in an Insured US Population.

OBJECTIVE: To investigate the epidemiology and treatment of rheumatoid arthritis (RA) in a population broadly representative of employed adults in the US, using a retrospective cohort design. METHODS: Incident and prevalent RA cohorts were defined from a sample of 4.66 million adults with complete followup data from the period of January 2005 through September 2008 in the Pharmetrics medical claims database. Demographics, comorbidity, and medical therapies were summarized using descriptive statistics. RESULTS: Median duration in the database was 5.7 years. Age- and sex-adjusted incidence in 2006 was 0.71 per 1,000 persons at risk (n = 3,992) and prevalence in 2005 was 0.63% (n = 30,530). Within 12 months after diagnosis, 65%, 64%, and 20% of the incident cohort had been prescribed corticosteroids, nonbiologic disease-modifying antirheumatic drugs (DMARDs), and tumor necrosis factor (TNF) inhibitors, respectively. Median time to first anti-TNF prescription was 6 months; 31% switched to a second drug and 15% to a third. An aggressive subcohort (11% of incident patients) received more DMARDs (83%) and TNF inhibitors (43%), and was more likely to switch. Twenty-eight percent of incident patients received only symptomatic therapy over a minimum of 1.75 years of followup; these patients were older with more comorbidities and contraindications to methotrexate. CONCLUSION: In this insured population-based cohort, only two-thirds of newly diagnosed RA patients were prescribed a DMARD in year 1 and 28% received no antirheumatic therapy. Although limited by lack of clinical information and by left-censoring, administrative databases capture clinical practice and suggest that gaps exist in treatment options available to a significant number of patients.

Conclusions about the effects on fertilization of time from aspiration to incubation and blood in the aspirate depend on the use of appropriate statistical techniques.

OBJECTIVE: To examine the effects of exposure to blood and time from aspiration to incubation on oocyte fertilization. DESIGN: Retrospective, cohort study. SETTING: Hospital-based IVF practice. PATIENT(S): Eighty-two women undergoing IVF procedures. INTERVENTION(S): Patients received a standard gonadotropin protocol or a microdose flare protocol. MAIN OUTCOMES MEASURE(S): Logistic regression was used to estimate odds of nonfertilization, adjusting for maternal age, time from aspiration to incubation, presence of blood in the aspirate, and a time-by-blood interaction. Two statistical methods were used: an analysis that assumed oocytes were independent and an analysis that adjusted for the lack of independence of oocytes within mothers (i.e., cluster-correlated data). RESULT(S): The 82 women contributed 1093 oocytes. In a model with blood dicotomized as present or absent, and with time elapsed and maternal age categorized into quartiles, both time and maternal age were statistically significant when conventional logistic regression was used. In analyses that accounted for clustering within mother, retrieval-to-incubation times more than 4 minutes were associated with an increased risk of nonfertilization, but age and blood were not; there was no evidence of an interaction between time elapsed and blood. CONCLUSION(S): If appropriate statistics are applied, retrieval-to-incubation times more than 4 minutes are associated with increased risk of nonfertilization.

Effect of community coalition structure and preparation on the subsequent implementation of cancer control activities.

PURPOSE: The purpose of this paper is to identify factors within a three-phase community coalition development model that influence short-term success in cancer control coalitions based on the cumulative number of educational and screening activities conducted by the coalitions. DESIGN: This study was a nonrandomized community intervention trial involving four autonomous, independently funded multistate projects aimed at using coalitions to increase cancer screening and early detection. SETTING: The study was conducted in medically underserved, rural counties of Appalachia. SUBJECTS: Sixty-three coalitions involved 1725 members representing 71 counties within 10 states. Intervention. A network of local and regional community cancer control coalitions throughout rural Appalachia delivered culturally sensitive cancer control messages to women, with the long-term goal of increasing the early detection of breast cancer ANALYSIS: County-level coalitions were the unit of analysis for this study. Multiple linear regression was used to determine if three classes of variables corresponding to the developmental history of coalitions--formation, preparation for implementation, and implementation--were associated with the number of educational and screening activities conducted by the coalitions. RESULTS: The presence of a paid coordinator and formal organizational structure were both strongly associated with the number of activities conducted, accounting for 71% of the variability in coalition activities. Other variables positively associated with number of activities were the preparation of written community assessments and the modification of implementation plans. The same factors (structure, written plans) were associated with activities in coalitions without paid organizers (r2 = .57), as was the number of meetings. However, such coalitions produced an average of only 2.2 activities vs. 21.7 activities in coalitions with paid coordinators. CONCLUSION: The ALIC study would seem to indicate that community-based coalitions with paid coordinators and formal structures are capable of generating significantly higher levels of activity than those without either a paid coordinator or formal structure.

Effect of topotecan infusion duration on hematologic toxicity in recurrent ovarian carcinoma.

In an open-label, multicenter, nonrandomized, counterbalanced study, we investigated the tolerability and antitumor profile of a 10-min infusion duration of topotecan. A total of 12 patients with evaluable recurrent ovarian cancer were enrolled into the study and treated with 1.5 mg/m2/d topotecan for 5 d of a 21-d course by either a 10-, 30-, or 120-min intravenous infusion. Patients were evaluated for tolerability and tumor response. The primary toxicity associated with topotecan was noncumulative myelosuppression. All 12 patients experienced grade 3/4 neutropenia. Grade 3/4 thrombocytopenia, leukopenia, and anemia were reported in five (42%), two (17%), and two (17%) patients, respectively. Likewise, the majority of courses were associated with hematologic toxicity, with grade 3/4 neutropenia, thrombocytopenia, leukopenia, and anemia reported in 97%, 19%, 6%, and 6% of courses, respectively. The infusion duration had little impact on the myelotoxicity profile of topotecan. The mean nadir levels for all hematologic parameters were similar for all infusion durations, and myelosuppression was reversible and returned to near-preinfusion levels prior to administering the subsequent course, irrespective of infusion duration. A complete response was obtained by three (25%) patients, and five (42%) patients achieved stable disease; therefore, 67% of patients obtained clinical benefit. The results of this study demonstrate that topotecan administered over a 10-min interval has a comparable tolerability and safety profile compared with a 30-min infusion. A 10-min infusion may result in greater patient convenience and a reduction in the consumption of healthcare resources.

Clinical process improvement: reduction of pneumothorax and mortality in high-risk preterm infants.

OBJECTIVE: To develop multidisciplinary clinical process improvement methods using evidence-based medicine to decrease the incidence of pneumothorax in a NICU. STUDY DESIGN: All inborn infants <28 weeks' gestation (n=79) served as the historical baseline group. A prospective protocol, using evidence-based medicine and a rapid-cycle, multidisciplinary clinical process improvement method, was designed to measure changes in the incidence of pneumothorax in subsequent infants of similar gestational ages. RESULTS: Sixty consecutive inborn infants <28 weeks' gestational age comprised the study group. In comparison to the historical control group, there was a significant reduction in the incidence of pneumothorax (from 26.6% to 10%, p=0.018) and in mortality (36.7% to 15%, p=0.007) without adversely affecting any other measured outcome variable. CONCLUSIONS: Introduction of multidisciplinary clinical process improvement methods can significantly decrease the incidence of adverse outcomes in neonatal intensive care units.