Continuous Independent Variables Research Articles

Can Physical Characteristics and Sports Bra Use Predict Exercise-Induced Breast Pain in Elite Female Athletes?

To evaluate whether a simple 4-factor model using self-reported data could be used to predict exercise-induced breast pain in elite female athletes. Survey study. Online or hard-copy surveys completed at sporting competitions and training facilities around Australia. Four hundred ninety female athletes competing nationally or internationally across 49 sports. A binomial logistic regression analysis was used to evaluate the strength of a predictive model that included 2 continuous independent variables (age and body mass index) and 2 binary independent variables (breast size and sports bra use). Odds ratios were also calculated to determine the likelihood of an athlete reporting exercise-induced breast pain in association with each of the 4 variables. Exercise-induced breast pain was the binary dependent variable. The model incorporating athlete age, breast size, body mass index, and sports bra use was found to be statistically significant, but weak, in its ability to predict exercise-induced breast pain in elite female athletes (correctly identified 66% of athletes). For every 1-year increase in age, a significant 2.6% increase in the likelihood of experiencing exercise-induced breast pain was observed. Athletes with medium-to-hypertrophic sized breasts were 5.5 times more likely to experience exercise-induced breast pain than athletes with small breasts. Although the current model was not sensitive enough for use by clinicians and coaches, age and breast size were both identified as critical variables in the prediction of exercise-induced breast pain. Future research is encouraged to investigate whether incorporating additional variables such body fat percentage, bra fit, and other relevant factors can add strength to the model.

Impact of Soil and Water Conservation Practice on Income in Chencha District, SNNP of Ethiopia

Land degradation, in the form of soil erosion and nutrient depletion, threatens food security and the sustainability of agricultural production in many developing countries. As part of intervention activities a number of soil and water conservation practices have been promoted to smallholder farmers living in highly degraded and drought prone areas of the country. This study was conducted to examine the impact of SWC intervention on the livelihood of smallholder farm households in terms household income. To meet this objective primary data was collected in 2019 from 146 SWC program participants and 130 non-participants that were randomly selected from 3 intervention area and 3 counterfactual peasant associations in Chencha district of SNNP respectively. Descriptive and inferential statistics and propensity score matching (PSM) models were used to address the stated objectives. Results of the descriptive statistics showed that before matching there was statistically significant difference between program participants and their counterfactual households in terms of farm size and participation in petty trade from continuous independent variables and from categorical variables sex of household, education of household head, biological and physical conservation method, intercropping as well as bench terrace were significant in favor of program participants. Results of the PSM model revealed that SWC intervention result in significant difference between program participant and nonparticipant households in terms of household income. Keywords: Chencha, Income, land degradation, PSM model, Soil and water conservation DOI: 10.7176/CER/12-2-01 Publication date: February 29 th 2020

Smoking Is Associated with Pain in All Body Regions, with Greatest Influence on Spinal Pain

Examine the interrelationship between smoking and pain in the US population. A cross-sectional population-based study. Nationwide survey. Comprehensive pain reports categorically defined as head, spine, trunk, and limb pain; smoking history; demographics; medical history from a total of 2,307 subjects from the 2003-2004 National Health and Nutrition Examination Survey obtained from the Centers for Disease Control were analyzed. Unpaired t tests were used to analyze independent continuous variables, and chi-square tests were used to analyze categorical variables between smoker and nonsmoker groups. Weighted multivariate logistic regression analyses determined the association of current smoking with the presence of pain in various body regions. Smoking is most strongly associated with spine pain (odds ratio [OR] = 2.89, 95% confidence interval [CI] = 2.21-3.77), followed by headache (OR = 2.47, 95% CI = 1.73-3.53), trunk pain (OR = 2.17, 95% CI = 1.45-2.74), and limb pain (OR = 1.99, 95% CI = 1.45-2.73). Current smoking is associated with pain in every region of the body. This association is strongest for spine and head pain. Given that pain is a strong motivator and that current smoking was associated with pain in all body regions, we recommend that these results be used to further raise public awareness about the potential harms of smoking.

Effect of Systolic Blood Pressure on Left Ventricular Structure and Function: A Mendelian Randomization Study.

We aimed to estimate the effects of a lifelong exposure to high systolic blood pressure (SBP) on left ventricular (LV) structure and function using Mendelian randomization. A total of 5596 participants of the UK Biobank were included for whom cardiovascular magnetic resonance imaging and genetic data were available. Major exclusion criteria included nonwhite ethnicity, major cardiovascular disease, and body mass index >30 or <18.5 kg/m2. A genetic risk score to estimate genetically predicted SBP (gSBP) was constructed based on 107 previously established genetic variants. Manual cardiovascular magnetic resonance imaging postprocessing analyses were performed in 300 individuals at the extremes of gSBP (150 highest and lowest). Multivariable linear regression analyses of imaging biomarkers were performed using gSBP as continuous independent variable. All analyses except myocardial strain were validated using previously derived imaging parameters in 2530 subjects. The mean (SD) age of the study population was 62 (7) years, and 52% of subjects were female. Corrected for age, sex, and body surface area, each 10 mm Hg increase in gSBP was significantly (P<0.0056) associated with 4.01 g (SE, 1.28; P=0.002) increase in LV mass and with 2.80% (SE, 0.97; P=0.004) increase in LV global radial strain. In the validation cohort, after correction for age, sex, and body surface area, each 10 mm Hg increase in gSBP was associated with 5.27 g (SE, 1.50; P<0.001) increase in LV mass. Our study provides a novel line of evidence for a causal relationship between SBP and increased LV mass and with increased LV global radial strain.

Overall Treatment Satisfaction 5Years After Bariatric Surgery.

Up to 30% of patients undergoing bariatric surgery are dissatisfied with treatment outcomes in the long term. The aim of this study was to examine overall satisfaction with treatment 5years after bariatric surgery and its association with body mass index (BMI) and health-related quality of life (HRQOL). Patients were surveyed 5years after bariatric surgery; 108 patients had duodenal switch (DS) and 153 patients had laparoscopic sleeve gastrectomy (LSG). The main outcome was overall treatment satisfaction, assessed by a single question, and analyzed by multiple logistic regression. Estimates for continuous independent variables represent the odds ratios (OR) for a 2-standard deviation difference. Five years after surgery, 82.4% of the patients were very satisfied or satisfied, whereas 17.6% were unsure or dissatisfied. The following variables assessed at 5years were associated with being dissatisfied/unsure: a higher BMI (OR = 6.1, 95% CI = 2.7-14.0, p < 0.001), reduced obesity-specific HRQOL (OR = 3.0, 95% CI = 1.1-7.8, p = 0.03), and reduced mental HRQOL (OR = 0.3, 95% CI = 0.1-0.8, p = 0.02). We also found that a higher proportion of patients who underwent LSG, compared to DS, reported being dissatisfied/unsure (OR = 3.3, 95% CI = 1.3-8.8, p = 0.01). Reduced mental HRQOL and obesity-related HRQOL, as well as higher BMI, were associated with less satisfaction with overall treatment outcomes 5years after bariatric surgery. Differences in overall treatment satisfaction by type of operation warrant further investigation.

Linear Mixed Effects Modelling of Oxygen Desaturation after Sleep Apneas and Hypopneas: A Pilot Study.

Obstructive Sleep Apnea severity is commonly determined after a sleep polysomnographic study by the Apnea-Hypopnea Index (AHI). This index does not contain information about the duration of events, and weights apneas and hypopneas alike. Significant differences in disease severity have been reported in patients with the same AHI. The aim of this work was to study the effect of obstructive event type and duration on the subsequent oxygen desaturation (SaO2) by mixed-effects models. These models allow continuous and categorical independent variables and can model within-subject variability through random effects. The desaturation depth dSaO2, desaturation duration dtSaO2 and desaturation area dSaO2A were analyzed in the 2022 apneas and hypopneas of eight severe patients. A mixed-effects model was defined to account for the influence of event duration (AD), event type, and their interaction on SaO2 parameters. A two-step backward model reduction process was applied for random and fixed effects optimization. The optimum model obtained for dtSaO2 suggests an almost subject-independent proportion increase with AD, which did not significantly change in apneas as compared to hypopneas. The optimum model for dSaO2 reveals a significantly higher increase as a function of AD in apneas than hypopneas. Dependence of on event type and duration was different in every subject, and a subject-specific model could be obtained. The optimum model for SaO2A combines the effects of the other two. In conclusion, the proposed mixed-effects models for SaO2 parameters allow to study the effect of respiratory event duration and type, and to include repeated events within each subject. This simple model can be easily extended to include the contribution of other important factors such as patient severity, sleep stage, sleeping position, or the presence of arousals.

OPTIMIZATION OF DESIGN PARAMETERS OF AUTOTRANSFORMERS IN ICE MELTING SCHEME WITH NON-INDUCTIVE CIRCUIT ON 6-10 KV OVERHEAD POWER LINES

Purpose. The purpose of the paper is to determine the basic electrical characteristics and to develop a calculation method and algorithm for optimizing the design parameters of autotransformers intended for use in a melting ice scheme with a non-inductive circuit on 6-10 kV overhead power lines. Methodology. The development of the technical and economic model and the method for calculation of the design parameters of the autotransformer for melting ice is performed on the basis of a systematic approach. Optimization of structural characteristics of autotransformers is carried out using a combined algorithm based on the spatial grid method, adapted to the case of a mixed space of discrete and continuous independent variables, and the specifics of the technical and economic model of the autotransformer. The proposed combined optimization algorithm is implemented in the Delphi environment. Results. Based on the required specific melting power, the main electrical characteristics of autotransformers intended for use in the melting ice scheme with a non-inductive circuit on 6-10 kV overhead lines, which were the basis for optimizing their design parameters, have been calculated. The technical and economical model of autotransformer for melting ice, which is defined by nine independent variables and describes its cost and technical parameters, is developed. On the basis of the obtained electrical characteristics, optimization of the design parameters of a series of autotransformers is carried out, which includes three standard sizes, differing in maximum length of the transmission line. Originality. A method of calculation of structural parameters of autotransformers for ice melting is proposed, the peculiarity of which is the use of the criterion of the minimum of the cost of the active part and taking into account the conditioned by the circuit of connection of the autotransformers the technical restrictions of errors on the value and angle of secondary current, which are important from the point of view of ensuring the permissible deviation of the specific power of melting ice. Practical value. Optimal correlations of geometrical sizes and electromagnetic loads of autotransformers for ice melting, their cost indicators, as well as the main design characteristics of the magnetic circuit and windings are established. Results of design calculation of autotransformers are sufficient for introduction of their serial production in industrial conditions.

1379-P: Type 1 Diabetes Mellitus and Periodontal Disease—Relationship with Pubertal Stage and Glycaemic Control

Background and Aims: Periodontal disease (PD) has been considered as the sixth complication of diabetes (DM). It has also been suggested that PD may worsen glycemic control. The present study has been designed to establish correlation between periodontal health status with pubertal stage and metabolic control in type 1 diabetes (T1D). Methodology: Oral hygiene index (OHI), gingival index (GI), probing pocket depth (PPD) and clinical attachment loss (CAL) were recorded in subjects with T1D (110) and healthy siblings (22). Duration, age, HbA1c and presence of microvascular complications was documented. Result: GI (p=0.044) and PPD (p=0.013) was worse in the cases vs. the controls. Greater PPD (p=0.026) in cases vs. the controls in stage II-IV puberty was seen and both worsening GI (p=0.038) and greater PPD (p=0.027) in the cases vs. controls in stage V despite better OHI (p=0.040). Pubertal staging revealed no difference in any of the studied dental parameters in stage 1. A binary logistic regression model with age, HbA1c and duration of DM as independent continuous variables, detected HbA1c as a significant predictor of PD. HbA1c along with stage of puberty rather than duration of DM and chronological age were found as important predictor of PD. PD was significantly associated with markers of nephropathy and neuropathy. Both the PPD and GI were found to have significant positive correlation with vibration perception threshold and microalbuminuria in the cases. A positive correlation was observed between HbA1c levels and albumin creatinine ratio (ACR) levels, p=0.010. Conclusion: T1D was more likely to develop PD compared to healthy siblings. Onset and progression of puberty and poorer glycaemic control, rather than duration of DM was associated with greater risk of PD. PD was more likely to be associated with markers of microvascular disease. Disclosure P. Chakraborty: None. S. Ghosh: None. Funding Department of Science &amp; Technology, Government of India, West Bengal; Research Society for the Study of Diabetes in India

Risk Factors for Infectious Complications in Patients Undergoing Retrograde Intrarenal Surgery.

To investigate the risk factors that may cause urinary tract infection (UTI) in patients applied with retrograde intrarenal surgery (RIRS). An observational study. Departments of Urology, Ankara Training and Research Hospital, Turkey, from September 2014 to April 2017. A retrospective examination was made of patients who underwent RIRS. The patients were separated into 2 groups as those with no UTI in the postoperative period (Group 1) and those with UTI (Group 2). The groups were compared in respect of age, stone size, operating time, presence of residual stone, and body mass index. Continuous independent variables were compared using the Student's t-test and in the comparison of categorical variables, the Chisquare test was used. A value of p<0.05 was accepted as statistically significant. Group 1 comprised 169 patients with no UTI and Group 2, 20 patients with UTI. The mean operating time was 55.82 ±14.73 minutes in Group 1 and 75.5 ±23.9 minutes in Group 2 (p=0.002). In multivariate analysis, operating time was determined as an independent prognostic risk factor increasing the risk of infection (p=0.001). The cut-off value determined with ROC analysis was 61 minutes. When operating time exceeded 61 minutes, the infection risk was increased 11.1-fold (sensitivity 75%, specificity 76%, AUC 0.76). Operating time in patients applied with RIRS was determined to be an independent prognostic risk factor for UTI risk in the postoperative period. In patients where surgery lasts more than 1 hour, particular attention should be paid in respect of infection risk.

Insights from kernel conditional-probability estimates into female labour force participation decision in the UK

The female labour force participation decision in the UK is a well-researched topic in empirical economics and econometrics. In this paper, using data from the UK Labour Force Survey in 2007, we contribute to the rich body of the literature by estimating a model using the kernel mixed-data-type conditional-probability (KMDTCP) estimator. We extend the analysis by comparing the predicted probabilities of the KMDTCP estimator with the estimates of a multinomial logit (MNL) model. Additionally, kernel smoothing specification tests are applied in order to compare different functional forms for the independent variables in the MNL model against the KMDTCP estimates. Our results demonstrate that the difference between the predictions from the KMDTCP estimator and the MNL is reduced when the functional form of continuous independent variables in the MNL model is relaxed to a semi-parametric form using dummy variables and interaction terms. The properties that are captured by the KMDTCP estimator show clearly that the propensity to work decreases with the increase in the number of dependent children. Furthermore, our analyses show that females older than 40 years of age have a high propensity to work irrespective of the number of dependent children.

Efeitos moderadores duplos e triplos e plots em análise de regressão

Distinguished international published papers examine mediator, moderator, moderator-mediator, mediator-moderator variables and indirect effects over the causal relationship in social sciences. Among the possible different ways of data interpretation, understand the moderating effect using linear regression analysis is an alternative. The main objective of this article is to discuss and to clarify theconcept of moderation, when using the multiple regression analysis instead of the traditional general linear models – GLM (e.g., MANOVA, ANCOVA, ANOVA, ANCOVA). The second goal is to apply three estimates: (a) two-way moderating effect with independent continuous variables, (b) two-way moderating effect with a continuous and a dummy variable as independent variables and (c) three-waymoderating effect with independent continuous variables, all using regression analysis. Third, the paper discusses the ordinal moderation and cross-over effects.The results showed that three-way interactions demand group analysis and were not used.

Application of Binary Logistic Regression Model to Assess the Likelihood of Overweight

This study attempts to assess the likelihood of overweight and associated factors among the young students by analyzing their physical measurements and physical activity index. This paper has classified four hundred and fifteen subjects and precisely estimated the likelihood of outcome overweight by combining body mass index and CUN-BAE calculated. Multicollinearity is tested with multiple regression analysis. Box-Tidwell Test is used to check the linearity of the continuous independent variables and their logit (log odds). The binary regression analysis was executed to determine the influences of gender, physical activity index, and physical measurements on the likelihood that the subjects fall in overweight category. The sensitivity and specificity described by the model are 55.9% and 96.9% respectively. The increase in the value of waist to height ratio and neck circumference and drop in physical activity index are associated with the increased likelihood of subjects falling to overweight group. The prevalence of overweight is higher (27.8%) in female than in male (14.7%) subjects. The odds ratio for gender reveals that the likelihood of subjects falling to overweight category is 2.6 times higher in female compared to male subjects.

Linear mixed-effects models and the analysis of nonindependent data: A unified framework to analyze categorical and continuous independent variables that vary within-subjects and/or within-items.

In this article we address a number of important issues that arise in the analysis of nonindependent data. Such data are common in studies in which predictors vary within "units" (e.g., within-subjects, within-classrooms). Most researchers analyze categorical within-unit predictors with repeated-measures ANOVAs, but continuous within-unit predictors with linear mixed-effects models (LMEMs). We show that both types of predictor variables can be analyzed within the LMEM framework. We discuss designs with multiple sources of nonindependence, for example, studies in which the same subjects rate the same set of items or in which students nested in classrooms provide multiple answers. We provide clear guidelines about the types of random effects that should be included in the analysis of such designs. We also present a number of corrective steps that researchers can take when convergence fails in LMEM models with too many parameters. We end with a brief discussion on the trade-off between power and generalizability in designs with "within-unit" predictors. (PsycINFO Database Record

Callous and uncaring traits are associated with reductions in amygdala volume among youths with varying levels of conduct problems.

The emergence of callous unemotional (CU) traits, and associated externalizing behaviors, is believed to reflect underlying dysfunction in the amygdala. Studies of adults with CU traits or psychopathy have linked characteristic patterns of amygdala dysfunction to reduced amygdala volume, but studies in youths have not thus far found evidence of similar amygdala volume reductions. The current study examined the association between CU traits and amygdala volume by modeling CU traits and externalizing behavior as independent continuous variables, and explored the relative contributions of callous, uncaring, and unemotional traits. CU traits and externalizing behavior problems were assessed in 148 youths using the Inventory of Callous Unemotional Traits (ICU) and the Child Behavior Checklist (CBCL). For a subset of participants (n = 93), high-resolution T1-weighted images were collected and volume estimates for the amygdala were extracted. Analyses revealed that CU traits were associated with increased externalizing behaviors and decreased bilateral amygdala volume. These results were driven by the callous and uncaring sub-factors of CU traits, with unemotional traits unrelated to either externalizing behaviors or amygdala volume. Results persisted after accounting for covariation between CU traits and externalizing behaviors. Bootstrap mediation analyses indicated that CU traits mediated the relationship between reduced amygdala volume and externalizing severity. These findings provide evidence that callous-uncaring traits account for reduced amygdala volume among youths with conduct problems. These findings provide a framework for further investigation of abnormal amygdala development as a key causal pathway for the development of callous-uncaring traits and conduct problems.

Optical coherence tomography as a predictor of visual recovery in patients with pituitary macroadenomas

ResumenIntroducción:Los macroadenomas hipofisarios tienen una elevada incidencia de pérdida visual como consecuencia de la compresión de la vía óptica. La tomografía de coherencia óptica (TCO) ha sido descripta como un factor pronóstico de recuperación. Nuestro objetivo es evaluar si la TCO puede predecir los resultados de recuperación visual.Métodos:Se realizó un trabajo prospectivo de macroadenomas hipofisarios con compresión de la vía visual e indicación quirúrgica entre febrero del 2015 y noviembre del 2016. Se evaluaron los estudios de agudeza visual, perimetría computarizada y TCO. Se compararon los resultados tras 6-12 semanas y 6-9 meses de la intervención. Las variables cuantitativas continuas dependientes e independientes se relacionaron mediante una prueba T de Student, regresión lineal y correlación de Pearson considerando como estadísticamente significativo una P < 0,05.Resultados:La alteración en la agudeza visual y la perimetría computarizada preoperatorios, fue mayor en aquellos pacientes con TCO alterada. Tanto los pacientes con CFNR normal como adelgazada se constató una mejoría significativa del campo visual a las 6-12 semanas. Los valores de TCO se correlacionaron en forma inversa con los valores de campo visual, lo que significa que a mayor grosor menor es el déficit campimétrico. Los pacientes con TCO normal tuvieron una mejor recuperación ya que el defecto campimétrico preoperatorio fue más leve. La correlación entre los valores de TCO y la mejoría del campo visual no fue significativa, lo que sugiere independientemente del grosor del nervio los pacientes mejoran el campo visual tras la cirugía.Conclusión:El campo visual computarizado continúa siendo el estudio de elección en la evaluación de pacientes con macroadenomas. La TCO no se considera un predictor de outcome visual.

Support indices: Measuring the effect of input variables over their supports

Two new sensitivity indices are presented which give an original solution to the question in sensitivity analysis of how to determine regions within the input space for which the model variation is high. The indices, as functions over the input domain, give insight into the local influence of input variables over the whole domain when the other variables lie in the global domain. They can serve as an informative extension to a standard analysis and in addition are especially helpful in the specification of the input domain, a critical, but often vaguely handled issue in sensitivity analysis. In the usual framework of independent continuous input variables, we present theoretical results that show an asymptotic connection between the presented indices and Sobol’ indices, valid for general probability distribution functions. Finally, we show how the indices can be successfully applied on analytical examples and on a real application.

The incidence and effect of noncylindrical neck morphology on outcomes after endovascular aortic aneurysm repair in the Global Registry for Endovascular Aortic Treatment

BackgroundThe Gore Global Registry for Endovascular Aortic Treatment (GREAT) was designed to evaluate real-world outcomes after treatment with Gore aortic endografts used in a real-world, global setting. We retrospectively analyzed the GREAT data to evaluate the incidence and effects of noncylindrical neck anatomy in patients undergoing endovascular aortic aneurysm repair. MethodsThe present analysis included patients with data in the GREAT who had been treated with the EXCLUDER endograft from August 2010 to October 2016. A noncylindrical neck was defined when the proximal aortic landing zone diameter had changed ≥2 mm over the first 15 mm of the proximal landing zone, indicating a tapered, conical, or hourglass morphology. Cox multivariate regression analyses were performed for any reintervention (including reinterventions on aortic branch vessels), device-related reinterventions, and reintervention specifically for endoleak. Independent binary (cylindrical vs noncylindrical necks) and continuous (percentage of neck diameter change) variables were assessed. The abdominal aortic aneurysm (AAA) diameter, proximal neck length, maximal infrarenal neck angle, gender, and use of aortic extender cuffs were also assessed. ResultsOf 3077 GREAT patients with available proximal aortic landing zone diameter measurements available, 1765 were found to have cylindrical necks and 1312 had noncylindrical necks. The noncylindrical neck cohort had a significantly greater proportion of women (17.4% vs 12.6%; P < .001) and more severe infrarenal angulation (33.8° vs 28.4°; P < .001). A total 14.7% of noncylindrical neck patients and 11.2% cylindrical neck patients underwent implantation outside of the EXCLUDER instructions for use regarding the anatomic inclusion criteria (P = .004). The procedural characteristics were similar between the two cohorts; however, noncylindrical neck patients required significantly more aortic extender cuffs (P = .004). The average follow-up was 21.2 ± 17.5 months and 17.8 ± 15.8 months for the cylindrical and noncylindrical cohorts, respectively (P < .001). The Cox multivariate regression models demonstrated female gender and maximum AAA diameter were significant risk factors for subsequent reintervention (overall, device-related, and endoleak-specific). Women were 2.2 times as likely to require device-related intervention during the follow-up period compared with men (P < .001). Neck shape morphology was not a significant predictor, except for device-related intervention, for which cylindrical necks (binary definition) resulted in a slightly elevated risk (1.5 times; P = .03). ConclusionsNoncylindrical neck morphology was more common in women and was associated with an increased use of aortic extender cuffs but did not increase the risk of intervention. Female gender and AAA diameter were associated with an increased need for reintervention.

A Retrospective Cohort Study to Determine Predictive Factors for Abdominal Wound Disruption Following Colorectal Surgery

Abdominal wound disruption (AWD) is a postoperative complication that increases length of hospital stay, mortality, and cost. A retrospective cohort study was conducted to identify predictors of AWD, defined in the National Surgical Quality Improvement Program User Guide as a spontaneous reopening of a previously surgically closed (midline) wound that occurs within 30 days after index elective surgery in patients undergoing colorectal surgery. Data from the American College of Surgeons National Surgical Quality Improvement Program (2006-2012) were searched, supplemented by institutional review board-approved chart review. Patients were identified using Current Procedural Terminology codes for open and laparoscopic abdominal colorectal procedures. Data were collected to predefined worksheets and entered into a statistical analysis program and included demographics; comorbidities; pre- and postoperative laboratory tests including white blood count, blood glucose, and albumin levels; date and type of procedure; wound classification; postoperative complication rate; type of access; time to disruption; surgical site infection (SSI); and use of the SSI intervention/prevention bundle. The Wilcoxon rank sum test was utilized to compare independent continuous variables between the groups, and Fisher's exact test was utilized to compare categorical variables. Variables with a P value <.2 at univariate logistic regression were included in multivariate logistic regression analysis. Time-to-event variables were compared using Cox regression analysis. Of the 690 patients included in the study, 16 (2.3%) developed an AWD. Mean age was 61.9 ± 15.3 years and 61.3 ± 15.0 years in AWD and non-AWD groups, respectively (P = .704). AWD occurred more frequently in men than women (75% vs. 50%; P = .040) and in patients who did compared to those who did not develop a deep incisional SSI (12.5% vs. 2%; P = .044). Preoperative albumin level was significantly lower in AWD (3.2 ± 0.8 vs. 3.8 ± 0.7; P = .006), as well as the proportion of post-bundle implementation (18.75% vs. 65.7%; P = .041). No significant differences were observed for any of the other variables examined. Per multivariate analysis, male gender (P = .05), absence of SSI bundle (P = .026), and hypoalbuminemia (P = .01) were independent predictors of AWD after elective colorectal resections. Time to AWD was significantly shorter in patients without SSI (P <.001). Results indicate implementation of the SSI bundle decreased AWD rates. Further prospective studies are needed to confirm these findings.

A novel heat exchanger design method using a delayed rejection adaptive metropolis hasting algorithm

In this study, a shell-and-tube heat exchanger (STHX) design based on seven continuous independent design variables is proposed. Delayed Rejection Adaptive Metropolis hasting (DRAM) was utilized as a powerful tool in the Markov chain Monte Carlo (MCMC) sampling method. This Reverse Sampling (RS) method was used to find the probability distribution of design variables of the shell and tube heat exchanger. Thanks to this probability distribution, an uncertainty analysis was also performed to find the quality of these variables. In addition, a decision-making strategy based on confidence intervals of design variables and on the Total Annual Cost (TAC) provides the final selection of design variables. Results indicated high accuracies for the estimation of design variables which leads to marginally improved performance compared to commonly used optimization methods. In order to verify the capability of the proposed method, a case of study is also presented, it shows that a significant cost reduction is feasible with respect to multi-objective and single-objective optimization methods. Furthermore, the selected variables have good quality (in terms of probability distribution) and a lower TAC was also achieved. Results show that the costs of the proposed design are lower than those obtained from optimization method reported in previous studies. The algorithm was also used to determine the impact of using probability values for the design variables rather than single values to obtain the best heat transfer area and pumping power. In particular, a reduction of the TAC up to 3.5% was achieved in the case considered.

Evaluating the Prediction of Breast Cancer Survival Using Lymph Node Ratio.

PurposePrevious oncological studies showed that lymph node ratio (LNR) (ratio of number of lymph nodes that tested positive for metastasis to the total number of lymph nodes examined) is a negative indicator of cancer survival. The American Joint Committee on Cancer (AJCC) staging system incorporates tumor size, lymph node involvement, and metastasis in a comprehensive model of cancer progression, but LNR alone has been shown to outperform the AJCC system in prognostic and survival predictions for various types of cancer. The effectiveness of LNR has not been evaluated in breast cancer staging. Evaluating LNR for predicting cancer staging in breast cancer has the potential to improve treatment recommendations.MethodsThe Surveillance, Epidemiology, and End Results dataset was used to identify 10,655 breast cancer patients who underwent nodal evaluation from 2010 to 2013, and their LNRs were calculated. Descriptive statistics of lymph node evaluation in the patients are provided. Logistic regression with LNR as the continuous independent variable was conducted to determine whether LNR could predict cancer progression, coded as regional or distant. Analysis was conducted using SPSS version 24.ResultsPatient's mean age was 59.43±18.62. Logistic regression analysis revealed that for every 1.3% increase in LNR, the odds of falling into the distant stage of the TNM staging system increased by 13.7% (odds ratio, 14.73; 95% confidence interval, 12.00–18.08).ConclusionLNR, while correlated with breast cancer staging, serves as a better predictor of survival. Precision staging can influence treatment modality, and improved treatments can significantly improve quality of life. Additional research and diagnostic examinations using LNR as a potential tool for accurate staging in breast cancer patients are warranted.