Non-significant Variables Research Articles

Surveillance for Lyme disease in Canada: 2009-2015

ObjectiveThis study aims to describe incidence over time, geographic and seasonal distribution, demographic and clinical characteristics of Lyme disease cases in Canada.IntroductionLyme disease (LD), a multisystem infection that is manifested by progressive stages (1), is emerging in central and eastern provinces of Canada due to northward expansion of the geographic range of Ixodes scapularis, the main vector in these regions (2). In 2004, approximately 40 human cases of LD were reported in Canada. In 2009, LD disease became nationally notifiable, with provincial and territorial health departments reporting clinician-diagnosed cases to the Public Health Agency of Canada (PHAC). This study summarizes seven years (2009-2015) of national surveillance data for LD in Canada.MethodsNational Lyme disease surveillance data is collected through two surveillance systems, the Canadian National Disease Surveillance System (CNDSS) and the Lyme disease enhanced surveillance system (LDES). The CNDSS collects only demographic data (age and sex), and information on episode date and case classification. The LDES system captures additional data, including: possible geographic location of infection (for both locally acquired and travel-related cases); clinical manifestations; and results of laboratory testing. Nine provinces out of ten participate to LDES that means they provide a part of or all the data elements of this surveillance system. The 2009 national Lyme disease case definition (3) that distinguishes confirmed and probable cases (Table 1) is used to classify and report cases diagnosed by clinicians.This study describes the incidence over time, seasonal and geographic distribution, demographic and clinical characteristics of reported LD cases. Logistic regression was used to explore variations among age groups, sex and year of reporting clinical manifestations to better understand potential demographic risk factors for the occurrence of LD. Different models were used with as outcomes absence or presence of: erythema migrans (early Lyme disease), neurologic and cardiac symptoms and multiple erythema, migrans (early disseminated Lyme disease); and arthritis (late disseminated Lyme disease). The most parsimonious multivariate models were sought by backward elimination of nonsignificant variables until all factors in the model were significant (P<0.05).ResultsThe number of reported LD cases increased more than six-fold, from 144 in 2009 to 917 in 2015, mainly due to an increase in infections acquired in Canada. For the provinces participating into the LDES system, the month of illness onset for Lyme disease cases acquired in Canada was available for 2010 cases. Most cases were reported during the summer months of June (20.7%), July (35.4%) and August (17.3%) (Figure 1). An increase in incidence of LD was observed in provinces from Manitoba eastwards (Figure 2). This is consistent with our knowledge of range expansion of the tick vectors in this region. In the western provinces the incidence has remained low and stable. All cases reported by Alberta, Saskatchewan and Newfoundland and Labrador were acquired outside of the province, either elsewhere in Canada or abroad. There was a bimodal distribution for LD by age with peaks at 5–9 and 45–74 years of age (Figure 3). The most common presenting symptoms were a single erythema migrans rash (74.2%) and arthritis (35.7%) (Figure 4). In the multivariate analysis for clinical manifestations, children aged 0–9 years had a greater number of cases reported as early LD (erythema migrans only) than patients aged 10–19 and 30–39 years (P<0.05). For early disseminated manifestations, young adults 20–29 years of age reported more neurologic manifestations, cardiac manifestations or multiple erythema migrans than the reference age group of 0–9 years (P<0.05). For late disseminated manifestations, children under 15 years of age were more frequently reported as having arthritis than other age groups.ConclusionsLyme disease incidence continues to increase in Canada as does the geographic range of ticks that carry the LD bacteria. This increasing of LD incidence might also be due to changing in knowledge, attitudes, and practices of clinicians who diagnose the disease and or of the public health workers who collect and report the data. Ongoing surveillance, preventive strategies as well as early disease recognition and treatment will continue to minimize the impact of LD in Canada.

Is the Importance of Heart Dose Overstated in the Treatment of Non-Small Cell Lung Cancer? A Systematic Review of the Literature

Some recent studies have suggested a relationship between cardiac dose and mortality in non-small cell lung cancer (NSCLC), but others have reported conflicting data. The goal of this study was to conduct a systematic review and meta-analysis to provide an evidence-based estimate of the relationship between cardiac dose and mortality in these patients. A systematic review of MEDLINE (PubMed) and Embase databases (inception to January 2018) was performed according to PRISMA guidelines. Studies that evaluated cardiac dosimetric factors in patients with NSCLC and included outcomes of cardiac events, cardiac mortality, and/or overall survival were identified. From 5614 patients across 22 studies, a total of 214 cardiac dosimetric parameters (94 unique) were assessed as possible predictors of cardiac toxicity or death. Assessed predictors included general (eg, mean heart dose [MHD]), threshold-based (eg, heart V5), and anatomic-based (eg, atria, ventricles) dosimetric factors. The most commonly analyzed parameters were MHD, heart V5, and V30. Most studies did not make corrections for multiplicity of testing. For overall survival, V5 was found to be significant on multivariable analysis (MVA) in 1 of 11 studies and V30 in 2 of 12 studies; MHD was not significant in any of 8 studies. For cardiac events, V5 was found to be significant on multivariable analysis in 1 of 2 studies, V30 in 1 of 3 studies, and MHD in 2 of 4 studies. A meta-analysis of the data could not be performed because most negative studies did not report effect estimates. Consistent heart dose-volume parameters associated with overall survival of patients with NSCLC were not identified. Multiplicity of testing is a major issue and likely inflates the overall risk of type I errors in the literature. Future studies should specify predictors a priori, correct for multiplicity of testing, and report effect estimates for nonsignificant variables.

Interpersonal Conflict Among Nurses in Tertiary Hospitals in Dali, the People’s Republic of China

Interpersonal conflict is the interpersonal clashes, tension, animosity, and jealousy that occur between people. It is considered destructive as it is characterized by power struggles and personal issues and negatively affects group decision-making and task implementation. The aim of this study was to assess interpersonal conflict between nurses in tertiary hospitals in Dali, the People’s Republic of China, and the relationship between interpersonal conflict and the nurses’ various socio-demographic characteristics. The study found that, overall, nurses perceived a low level of interpersonal conflict. Nurses’ age, marital status, education level, work time, appointment status, and work experience were non-significant variables, and job status a significant variable associated with interpersonal conflict score. This study provides baseline information about nurses’ interpersonal conflict. Nurse managers should use this study’s results to develop positive working environments and reduce interpersonal conflict among nurses.

Measuring West-Africa Ports Efficiency Using Data Envelopment Analysis

The present study measured the relative efficiency of five major commercial ports in West Africa, using three different Data Envelopment Analysis (DEA) methods, the CCR, BCC, and Windows I-C methods over the years 2005-2016. Seven input variables and one output variable were used in the model analysis. The CCR and BCC methods were used to evaluate the technical and scale efficiency while the Windows I-C method provided a comprehensive ranking of the studied ports. The results showed that the scale efficiency score of 89.53% indicated that on average the production scale of the ports had deviated from the most productive scale size (MPSS) by 10.47%. These results revealed that the source of the overall inefficiency is due to scale rather than pure technical inefficiency. Hence, in order to improve the overall efficiency, the two scaled inefficient ports of Abidjan and Cotonou should adjust their scale of operations. Then, further investigations were conducted to detect correlations between various variables used in this study. The research found that the absence of any correlation for non-significant variables and negative correlation for the significant variables throughout time resulted from the fact that these variables were not fully utilized. Meaning that they were not efficiently used to boost the container throughput on a scale basis, the research also found that a pandemic or insecurity could easily impact seaports activities with the case of the Ebola outbreak which strucked the West African region from the year 2013 to 2016, or the terrorism threats which prevailed in the region around the year 2012. Thus, for ports to stand out in the present fiercely competitive environment, ports authorities ought to analyze their operational scale to identify whether or not the production size is fitting before further port capacity expansion.

Histopathological Changes in Gallbladder Mucosa Associated with Cholelithiasis: A Prospective Study.

Background and Aims:Cholelithiasis is known to produce diverse histopathological changes in the gallbladder mucosa. In the present study, we aimed to find the correlation between various gallstone characteristics (i.e., number, size, and morphological type) with the type of mucosal response in gallbladder mucosa (i.e., inflammation, hyperplasia, metaplasia, and carcinoma).Methods:The present study was conducted prospectively on 100 patients undergoing cholecystectomy for symptomatic cholecystitis. Gallstones were assessed for various parameters, i.e., number, size, and morphological type. Gallbladder mucosa was subjected to histopathological examination. Sections were taken from body, fundus, and neck of gallbladder.Results:Of 100 cases, maximum type was of mixed stones (54%) and was multiple in number (46%). However, gallstone type and number are nonsignificant variables to produce precancerous lesions (i.e., hyperplasia and metaplasia). Statistically significant results were obtained while comparing the mucosal response with gallstone size (P = 0.012).Conclusion:As the gallstone size increases, the response in gallbladder mucosa changes from cholecystitis, hyperplasia, and metaplasia to carcinoma. Gallstone type and number are nonsignificant variables to produce precancerous lesions.

Motorcyclist injury risk as a function of real-life crash speed and other contributing factors

The Vision Zero approach advocates for a road transport system designed with human injury tolerance and human fallibility as its basis. While biomechanical limits and the relationship between speed and injury outcome has been extensively investigated for car occupants and pedestrians, research analyzing this relationship for motorcyclists remains limited. The aim of this study was to address this issue by developing multivariate injury risk models for motorcyclists that estimate the relationship between speed and injury severity. For that purpose, motorcycle injury crashes from the German In-Depth Accident Study (GIDAS) database for the period 1999–2017 (n = 1037) were extracted. Different models were tested using logistic regression and backwards elimination of non-significant variables. The best fitting model in the current study included relative speed, type of crash opponent, impact location on the motorcycle and impact mechanism of the rider during the crash. A strong and significant relationship between relative speed and injury severity in motorcycle crashes was demonstrated. At 70 km/h, the risk for at least serious injuries in collisions with wide objects, crash barriers and narrow objects was 20%, 51%, and 64%, respectively. Further, it was found that head-on collisions between motorcycles and passenger cars, with both vehicles traveling at 60 km/h (a relative speed at 120 km/h), present 55% risk of at least serious injury to the motorcycle rider.More research is needed to fully understand the boundary conditions needed to design a safe road transport system for motorcyclists. However, this study provides important insights into the relationship between speed and injury severity for riders in various crash situations. The results may be useful in the discussion of appropriate speed limits and in determining the benefits of countermeasures which aim to reduce crash speed.

Intervention for arch obstruction after the Norwood procedure: Prevalence, associated factors, and practice variability

ObjectiveArch obstruction after the Norwood procedure is common and contributes to mortality. We determined the prevalence, associated factors, and practice variability of arch reintervention and assessed whether arch reintervention is associated with mortality. MethodsFrom 2005 to 2017, 593 neonates in the Congenital Heart Surgeons' Society Critical Left Heart Obstruction cohort underwent a Norwood procedure. Median follow-up was 3.7 years. Multivariable parametric models, including a modulated renewal analysis, were performed. ResultsOf the 593 neonates, 146 (25%) underwent 218 reinterventions for arch obstruction after the Norwood procedure: catheter-based (n = 168) or surgical (n = 50) at a median age of 4.3 months (quartile 1-quartile 3, 2.6-5.7). Interdigitation of the distal aortic anastomosis was protective against arch reintervention. Development of ≥ moderate tricuspid valve regurgitation and right ventricular dysfunction at any point was associated with arch reintervention. Nonsignificant variables for arch reintervention included shunt type and preoperative aortic measurements. Surgical arch reintervention was protective against arch reintervention, but transcatheter reintervention was associated with increased reintervention. Arch reintervention was not associated with increased mortality. There was wide institutional variation in incidence of arch reintervention (range, 0-40 reinterventions per 100 years patient follow-up) and in preintervention gradient (range, 0-64 mm Hg). ConclusionsInterdigitation of the distal aortic anastomosis during the Norwood procedure decreased the risk of arch reintervention. Surgical arch reintervention is more definitive than transcatheter. Arch reintervention after the Norwood procedure is not associated with increased mortality. Serial surveillance for arch obstruction, integrated with changes in right ventricular function and tricuspid valve regurgitation, is recommended after the Norwood procedure to improve outcomes.

Soil Chemical Properties Barely Perturb the Abundance of Entomopathogenic Fusarium oxysporum: A Case Study Using a Generalized Linear Mixed Model for Microbial Pathogen Occurrence Count Data.

Fusarium oxysporum exhibits insect pathogenicity—however, generalized concerns of releasing phytopathogens within agroecosystems marred its entomopathogenicity-related investigations. In a previous study, soils were sampled from Douro vineyards and adjacent hedgerows. In this study, 80 of those soils were analyzed for their chemical properties and were subsequently co-related with the abundance of entomopathogenic F. oxysporum, after insect baiting of soils with Galleria mellonella and Tenebrio molitor larvae. The soil chemical properties studied were organic matter content; total organic carbon; total nitrogen; available potassium; available phosphorus; exchangeable cations, such as K+, Na+, Ca2+, and Mg2+; pH; total acidity; degree of base saturation; and effective cation exchange capacity. Entomopathogenic F. oxysporum was found in 48 soils, i.e., 60% ± 5.47%, of the total soil samples. Out of the 1280 insect larvae used, 93, i.e., 7.26% ± 0.72%, were found dead by entomopathogenic F. oxysporum. Stepwise deletion of non-significant variables using a generalized linear model was followed by a generalized linear mixed model (GLMM). A higher C:N (logarithmized) (p < 0.001) and lower exchangeable K+ (logarithmized) (p = 0.008) were found significant for higher fungal abundance. Overall, this study suggests that entomopathogenic F. oxysporum is robust with regard to agricultural changes, and GLMM is a useful statistical tool for count data in ecology.

Modified flash flood potential index in order to estimate areas with predisposition to water accumulation

Abstract The purpose of this study is to bring a series of changes to the potential flashed-flood index proposed and used by Smith (2003), to estimate floodplains in the upper part of Trotus Basin. Trotuş Basin is located in the central - eastern part of the Eastern Carpathians (Romania) having an area of 4.456 km2. The Trotus Basin is recognized as a basin where floods occur frequently due to climatic factors (precipitation, air temperature and winds) as well as due to the morphological characteristics (altitude, slope and versants orientation) that favour the formation of these phenomena. To develop a modified Flash Flood Potential Index was used six physical-geographical factors: land use, soil texture, rock’s permeability, slope, profile curvature and flow accumulation. Each thematic layer has been classified in five classes, from 1 to 5, where 1 means a low contribution and 5 a strong contribution of factors in water accumulation and each factor was weighted according to its importance. The result was a grid layer representing the flood potential index. The maximum flood hazard was associated with an area of approximate 10% from the studied surface. To see the contribution of each factor in the achievement of this index a multiple linear regression was made. The result shows that three variables are statistically significant and explain 91.6% from the model. This means that MFFPI can be obtained only from these three significant factors (flow accumulation, profile curvature and land cover) in order to identify areas with flood predisposition, the non-significant variables being removed. In order to verify these results the obtained MFFPI was compared with the flood hazard map for this area and the procedure showed that this index can be used in the identification of the flood-predisposed areas.

Is the Importance of Heart Dose Overstated in Non-Small Cell Lung Cancer? A Systematic Review of the Literature

Thoracic radiation has been associated with increased cardiac toxicity and mortality in studies of patients with breast cancer and Hodgkin Lymphoma. However, this impact is not well studied in patients with non-small cell lung cancer (NSCLC). Recent studies have suggested a relationship between cardiac dose and mortality, but the strength of the relationship and the optimal dosimetric predictors are unknown. The goal of this study was to conduct a systematic review and meta-analysis to provide an evidence-based estimate of the relationship between cardiac dose and mortality in patients with NSCLC. A systematic review of MEDLINE (PubMed) and Embase databases (inception to January 2018) according to PRISMA guidelines was performed. Studies which evaluated cardiac dosimetric factors in patients with NSCLC and which include outcomes of cardiac events, cardiac mortality and overall survival were identified. After the initial search (n= 461), studies were screened by title (n= 78), then by abstract (n= 33), and then included for full text review (n=22). From 6240 patients across 22 studies, a total of 214 cardiac dosimetric parameters (84 unique parameters) were assessed as possible predictors of cardiac toxicity or death, with a mean of 10 dosimetric factors assessed per study. Predictors assessed included general dosimetric factors (e.g. mean and maximum heart doses), factors based on threshold doses (e.g. heart V5), and factors based on doses to anatomic structures or sub-volumes (e.g. atria, ventricles). The most commonly analyzed parameters were mean heart dose (MHD), heart V5 and V30. Most studies did not make corrections for multiplicity of testing. For the endpoint of overall survival, V5 was found to be significant on multivariable analysis (MVA) in 1 of 11 studies, V30 significant in 2 of 12 studies and MHD was not significant in any of 8 studies. For the endpoint of cardiac events, V5 was found to be significant on MVA in 2 of 4 studies, V30 in 1 of 3 studies, and MHD in 2 of 4 studies. There was little overlap in the sub-volume parameters included in multivariable models across studies. A meta-analysis of the data could not be performed, as most negative studies did not report effect estimates (e.g. hazard ratios) and could not be meta-analyzed. Heart dose-volume constraints are not consistently associated with overall survival of NSCLC patients. Multiplicity of testing is a major issue and likely inflates the overall rate of type I error in the literature. Future studies should specify predictors a priori, correct for multiplicity of testing, and report effect estimates for non-significant variables.

Model of process parameters and sectional shape of samples in Single-layer Single-pass Sn63Pb37 Fused Coating Additive Manufacturing

Fused coating additive manufacturing is proposed to improve forming efficiency and material utilization. The forming property of single-layer single-pass is the basis of the process. The size of the sedimentary section is the smallest feature unit which includes the layer-height and pass-width. In this paper, the Design Expert 8.0.6 software is used to design the single-layer single-pass central composite experiment. In the reasonable parameters, the quadratic regression equations between the single layer cross-sectional size and process parameters were established by performing the second regression experiments. The misalignment and significance of the quadratic regression equations were checked and the non-significant variables in the regression model equation were excluded. The quantitative influences of main forming parameters on the single-layer single-pass cross-sectional size were finally analysed in detail.

Short communication: Model for metritis severity predicts that disease misclassification underestimates projected milk production losses

The objective of this research was to determine the effect of disease misclassification on the estimated effect of metritis on milk production. Misclassification introduces bias that usually results in an underestimation of the association between exposure (disease) and the outcome of interest (milk production). This distorted measure of association results from the comparison of an affected population (some of which may not truly be affected) to a nonaffected population (which often includes affected subjects that are unidentified). A convenience sample of DairyComp305 (Valley Agricultural Software, Tulare, CA) data representing 1 yr of calvings (n = 3,277) from 1 Midwestern Holstein herd was used. This herd was chosen because of its ongoing efforts to consistently and completely record all clinical diseases, including the incidence of both mild and severe metritis cases. Metritis was defined as the presence of a flaccid uterus containing fetid fluids or a foul watery discharge within 14 d of calving. Cows that appeared clinically normal other than the discharge were considered mild and those with systemic signs of disease were classified as severe. The original data set included metritis recorded as mild, severe, or not recorded (NR), where no metritis was observed, and was considered to contain the metritis true severity (TrS). First, to evaluate the effect of misclassification bias, we retrospectively randomized 45% of mild metritis to be classified as NR to simulate inconsistent disease recording (IR); then, in a separate model, all mild metritis cases were changed to NR to simulate a situation of very poor disease recording (PR), where only the most severe cases are recorded. The TrS, IR, and PR data sets were analyzed separately in JMP (SAS Institute Inc., Cary, NC). An ANOVA was conducted for second test 305-d mature-equivalent milk projection (2nd305ME), and nonsignificant variables were removed, but the variable metritis was forced into all models. Based upon the TrS model, adjusting for effects of lactation group, month of calving, dystocia, twins, retained placenta, early-lactation mastitis, displaced abomasum, and significant interactions, a case of mild metritis was associated with 384 kg less 2nd305ME and a case of severe metritis was associated with 847 kg less 2nd305ME compared with no metritis. For the IR model, a case of mild metritis was associated with 315 kg less 2nd305ME and a case of severe metritis was associated with 758 kg less 2nd305ME compared with no metritis. For the PR model, severe metritis was associated with 680 kg less 2nd305ME compared with NR. The IR and PR models underestimated 2nd305ME loss for severe metritis cases by 89 and 166 kg/cow, and resulted in 180,441 and 330,256 kg of total milk loss unaccounted for at the herd level, respectively, compared with TrS. Overall, misclassification of metritis cases results in greater bias and largely underestimates the true association between metritis and the consequence costs of the disease.

Student and School-level Predictors of Pharmacy Residency Attainment

Objective. To identify student and school level predictors of pharmacy residency attainment. Methods. Data were collected from the American Association of Colleges of Pharmacy (AACP) and the Carnegie Classification of Institutions of Higher Education. Logistic multilevel modeling was used to examine the effects of select student and school level characteristics on pharmacy residency attainment, as indicated by students on the AACP Graduating Student Survey (GSS) from 2013 to 2015. Results. The dataset included 24,351 graduating pharmacy students from 101 schools and colleges of pharmacy. Predictors of residency attainment included working in an institutional pharmacy, female gender, student age, school age, and Research I classification. Nonsignificant variables included curriculum type, class size, and institutional control. Conclusion. Student and pharmacy school characteristics impact the likelihood of pharmacy residency attainment. Further research is needed to understand the mechanisms associated with these effects.

An Information Entropy-Based Sensitivity Analysis of Radar Sensing of Rough Surface

We apply Shannon entropy, an information content measure, in sensitivity analysis (SA), stemming from the fact that the essence of SA is to preserve the maximum information content of the parameters of interest that are inverted from the radar response. Then, the sensitivity to the observation configuration and surface parameters is subsequently analyzed. Attempts are also made to explore advantages, by maximizing the information content, of dual-polarization and multi-angle in improving the parameter retrieval from radar sensing of rough surface. Simulation results show that the entropy is a good indicator of the sensitivity of the radar response to the surface parameter, as it contains information on not only the probability distribution of the scattering coefficient but also on its deviation. By information entropy, richer details, to large extent, on the scattering behavior are offered through quantitatively predicting the scattering signal saturation, evaluating the effect of using multi-polarization and multi-angle observation configuration, and identifying non-significant variables. It is found that Shannon entropy, compared to Renyi entropy, appears to better represent the sensitivity with respect to monotonic variation and narrower parameter ranges. The proposed entropy-based SA method helps to deepen our understanding of the microwave scattering behavior in response to surface parameters.

Sulfide removal from petrochemical wastewater using catalytic wet air oxidation (CWAO) method

The presence of sulfide in wastewater is by the result of biological, physical and chemical processes which mostly takes place in the submerged portion of the sewage collection networks. The rate of sulfide generation depends on several factors including pH, temperature, concentration of organic materials and nutrients, sulfate concentrations, collection system parameters and performance, and the oxidation reduction potential (ORP). Dissolved sulfide could affect biological processes in wastewater treatment plants. Other problems by hydrogen sulfide emission were corrosion of sewer concrete pipes, release of obnoxious odors to the atmosphere, toxicity to sewer workers or human health, water supply and environment pollution, and economic effects. In this research, the main objective was to remove the sulfide content that present in the petrochemical process plant using Catalytic Wet Air Oxidation (CWAO) method.This research was done initially by collecting the wastewater form petrochemical plant. It was followed by the developement of the experimental system in the laboratory to run the preliminary study and the data obtained was use in screening study to detemine the best condition of sulfide removal. The best condition suggested then was optimized using Central Composite Design (CCD) method as a response surface methodology. Three independent factors such as temperature, residence time and catalyst loading that affect the degradation of sulfide are investigated using the 23 factorial analysis. Some of the independent factors were shown to have significant effect on sulfide removals (%). After removing the nonsignificant variables from the model, response surface method was used to obtain the optimum conditions and optimized using central composite design. 13 experiments with 2 factors were designed. These factors (or variables) were: the temperature and the residence time. A full-quadratic polynomial equation between the percentage of sulfide removal (as the response) and the studied parameters are established. The optimum ranges of variables were: 42.5°C for the temperature and 12.5 minutes for the residence time

Depression in Older Adults Among Community: The Role of Executive Function

Summary Background Although previous studies have proposed that elderly depression is associated with higher negative affect (NA) and lower positive affect (PA), the relationship between elderly depression and executive function remains controversial. Methods Participants were recruited from the community and assessed using the Mini-Mental State Examination, the Geriatric Depression Scale, PA and NA tests, the Modified Card Sorting test (MCST), and a test of verbal fluency (VF). The participants were 319 middle-aged people (mean age = 58.05) and 276 elderly people (mean age = 74.41). The participants in each age group were then divided into a depression group and a control group according to their geriatric depression scale scores. Results Compared to the middle-aged group, the elderly group displayed significantly poorer executive function. Compared to the elderly control group, the depressed elderly group displayed poorer executive function, but this phenomenon was not found in the middle-aged group. Stepwise regression analysis showed that the factors of depression were NA and low PA for both the middle-aged and elderly depression groups. However, executive function including MSCT and VF were non-significant variables in regression analysis. Conclusion Executive dysfunction in elderly people with depression may be associated with the age effect. As people with depression age, their executive dysfunction becomes more pronounced. An elevated NA and lack of PA can explain the severity of depression, but executive function cannot explain depression in either middle-aged or elderly people.

Load forecasting under changing climatic conditions for the city of Sydney, Australia

Abstract In the current context, climate change has become an unequivocal phenomenon. Although it primarily encompasses change in temperature, nevertheless other weather variables such as rainfall, wind speed, evaporation and humidity can also be affected as a result of climate change. Addressing the impacts of climate change on electricity demand is essential for predicting the future demand. For example, cooling and heating requirements change significantly with respect to climate change that may result to the change in electricity load demand. In this paper, a backward elimination based multiple regression approach is proposed for analyzing the influence of climatic variables on load forecasting. A correlation analysis has been carried out using Pearson’s correlation coefficient to examine the interdependency between different climatic variables in the context of Sydney, one of the most densely populated cities in Australia. Regression based analysis has been performed to examine the relationship between per capita electricity demand and associated climatic variables. ‘Degree Days’ concept has been utilized to determine balance point temperature. Backward elimination based multiple regression is used to exclude non-significant climatic variables and evaluate the sensitivity of significant variables related to the load demand. Average change in future per capita electricity demand has been predicted using the proposed approach for the city of Sydney, Australia. Results indicate that the demand for Sydney will increase by 6% by 2030.

Methodology for the development of normative data for Spanish-speaking pediatric populations.

To describe the methodology utilized to calculate reliability and the generation of norms for 10 neuropsychological tests for children in Spanish-speaking countries. The study sample consisted of over 4,373 healthy children from nine countries in Latin America (Chile, Cuba, Ecuador, Guatemala, Honduras, Mexico, Paraguay, Peru, and Puerto Rico) and Spain. Inclusion criteria for all countries were to have between 6 to 17 years of age, an Intelligence Quotient of≥80 on the Test of Non-Verbal Intelligence (TONI-2), and score of <19 on the Children's Depression Inventory. Participants completed 10 neuropsychological tests. Reliability and norms were calculated for all tests. Test-retest analysis showed excellent or good- reliability on all tests (r's>0.55; p's<0.001) except M-WCST perseverative errors whose coefficient magnitude was fair. All scores were normed using multiple linear regressions and standard deviations of residual values. Age, age2, sex, and mean level of parental education (MLPE) were included as predictors in the models by country. The non-significant variables (p > 0.05) were removed and the analysis were run again. This is the largest Spanish-speaking children and adolescents normative study in the world. For the generation of normative data, the method based on linear regression models and the standard deviation of residual values was used. This method allows determination of the specific variables that predict test scores, helps identify and control for collinearity of predictive variables, and generates continuous and more reliable norms than those of traditional methods.

Coral assemblages are structured along a turbidity gradient on the Southwestern Gulf of Mexico, Veracruz

Corals on the reef corridor of the southwestern Gulf of Mexico have evolved on a terrigenous shallow continental shelf under the influence of several natural river systems. As a result, water turbidity on these reefs can be high, with visibility as low as <1m, depending on reef location and season. Using a presence-absence species database from field surveys, literature search, and satellite data on sea surface temperature, turbidity and chlorophyll-a, the coral species composition and environmental variables were analyzed for the three main reef systems of the reef corridor of the southwestern Gulf of Mexico. Completeness of the data set was assessed using species accumulation curves and non-parametric estimators of species richness. Differences in coral assemblages’ composition between the reef systems were investigated using univariate (ANOVA) and multivariate (nMDS, ANOSIM, SIMPER) analyses and the relationship between the assemblages and environmental data was assessed using a forward selection process in canonical correspondence analysis (CCA) to eliminate non-significant environmental variables. The northern and central Veracruz reef systems share a similar number of coral species (p=0.78 mult. comp.) and both showed higher species richness than the southern system (p<0.001 mult. comp.). In terms of the assemblages’ structure, significant differences were found (ANOSIM R=0.3, p=0.001) with larger average dissimilitude between north-south (75.4% SIMPER) and central-south (74.2%) than north-central (27%) comparisons. Only environmental variables related to water turbidity and productivity were significant on the final CCA configuration, which showed a gradient of increasing turbidity from north to south. Reef geomorphology and the effect of turbidity help explain differences in coral assemblages’ composition. More studies are necessary to establish if turbidity could function as a refuge for future environmental stress. Each Veracruz reef system is at the same time unique and shares a pool of coral species. To protect these ecosystems it is necessary to effectively manage water quality and consider coral diversity on the reef corridor of the southwestern Gulf of Mexico.

Switchgrass Biomass Composition Traits and their Effects on its Digestion by Ruminants and Bioconversion to Ethanol

Six generations of divergent breeding in switchgrass (Panicum virgatum L.) for forage in vitro digestibility (IVDMD) resulted in significant changes in 20 biomass composition traits. Stepwise multiregression was used to determine which of the 20 composition traits had the largest significant effects on forage IVDMD and potential ethanol yield (ETOH) in a biorefinery. Switchgrass biomass samples from a field nursery containing the divergent switchgrass populations and families were harvested after flowering, dried, ground, and analyzed for composition traits by near‐infrared reflectance analyses using previously developed near‐infrared reflectance calibrations. After nonsignificant variables were eliminated, the resulting multiple regression models were highly significant (P &lt; 0.001) and accounted for 95 and 96%, respectively, of the total variation for both IVDMD and ETOH. Standardized partial regression coefficients were used to estimate the relative importance of each significant variable. The biomass composition factors that had the largest impact on both IVDMD and ETOH were esterified ferulates, p‐coumarate esters, specific cell wall sugars that are involved in the linkage of cell wall lignin to hemicellulose, N, and extracted fats. Klason lignin was not a significant variable in either regression analysis, even though it was strongly negatively correlated with both IVDMD and ETOH. The IVDMD test, which acted as a biological selection index in a long‐term population breeding program, impacted an array of switchgrass biomass composition traits whose relative effects on both IVDMD and ETOH had not been previously quantified.