bluuebunny/crossref_metadata_2025 huggingface dataset:
A Meta-analysis of the Effects of Oral Zinc in the Treatment of Acute and Persistent Diarrhea
Authors: Lukacik Marek , Thomas Ronald L. , Aranda Jacob V.
Published: February 2008

OBJECTIVE. Children in developing countries are at a high risk for zinc deficiency. Supplemental zinc has previously been shown to provide therapeutic benefits in diarrhea. The objective of this study was to examine the efficacy and safety of supplemental oral zinc therapy during recovery from acute or persistent diarrhea.

METHODS. We conducted a meta-analysis of randomized, controlled trials to compare the efficacy and safety of supplementary oral zinc with placebo in children with acute and persistent diarrhea. Results were reported using a pooled relative risk or a weighted mean difference. A total of 22 studies were identified for inclusion: 16 examined acute diarrhea (n = 15231), and 6 examined persistent diarrhea (n = 2968).

RESULTS. Mean duration of acute diarrhea and persistent diarrhea was significantly lower for zinc compared with placebo. Presence of diarrhea between zinc and placebo at day 1 was not significantly different in acute diarrhea or persistent diarrhea trials. At day 3, presence was significantly lower for zinc in persistent diarrhea trials (n = 221) but not in acute diarrhea trials. Vomiting after therapy was significantly higher for zinc in 11 acute diarrhea trials (n = 4438) and 4 persistent diarrhea trials (n = 2969). Those who received zinc gluconate in comparison with zinc sulfate/acetate vomited more frequently. Overall, children who received zinc reported an 18.8% and 12.5% reduction in average stool frequency, 15.0% and 15.5% shortening of diarrhea duration, and a 17.9% and 18.0% probability of reducing diarrhea over placebo in acute and persistent trials, respectively.

CONCLUSIONS. Zinc supplementation reduces the duration and severity of acute and persistent diarrhea; however, the mechanisms by which zinc exerts its antidiarrheal effect have not been fully elucidated.
Role of Obesity in Complicating and Confusing the Diagnosis and Treatment of Diabetes in Children
Authors: Jones Kenneth Lee
Published: February 2008

The alarming increase in the prevalence of obesity in children in the United States and globally raises major concerns about its future adverse impact on public health. One outcome of this disturbing trend that is already evident is the rapidly increasing incidence of type 2 diabetes at all ages. This disease, once thought to be nonexistent in children, is increasing coincident with obesity. This article addresses the role that obesity plays in type 2 diabetes and also explores its effects on other types of diabetes that occur in childhood. The new challenges for physicians who formulate a differential diagnosis of diabetes in children are discussed. Also examined are modifications of traditional diabetes treatment that can be helpful in combating the insulin resistance associated with obesity and that use medications that are not traditionally used in this age group. Cases are presented to illustrate certain points. An underlying thesis suggests that specific classification may not be as important to the clinician as the understanding of pathophysiologic factors that contribute to hyperglycemia in individual patients. Recommendations are offered to the practitioner for diagnosing and treating the obese child or adolescent with diabetes.
Preparing for Pediatric Emergencies: Drugs to Consider
Authors: Hegenbarth Mary A. ,   and the Committee on Drugs
Published: February 2008

This clinical report provides current recommendations regarding the selection and use of drugs in preparation for pediatric emergencies. It is not intended to be a comprehensive list of all medications that may be used in all emergencies. When possible, dosage recommendations are consistent with those used in current emergency references such as the Advanced Pediatric Life Support and Pediatric Advanced Life Support textbooks and the recently revised American Heart Association resuscitation guidelines.
WITHIN‐TRIAL CONTRAST: PIGEONS PREFER CONDITIONED REINFORCERS THAT FOLLOW A RELATIVELY MORE RATHER THAN A LESS AVERSIVE EVENT
Authors: Zentall Thomas R. , Singer Rebecca A.
Published: February 2008

When behavior suggests that the value of a reinforcer depends inversely on the value of the events that precede or follow it, the behavior has been described as a contrast effect. Three major forms of contrast have been studied: incentive contrast, in which a downward (or upward) shift in the magnitude of reinforcement produces a relatively stronger downward (or upward) shift in the vigor of a response; anticipatory contrast, in which a forthcoming improvement in reinforcement results in a relative reduction in consummatory response; and behavioral contrast, in which a decrease in the probability of reinforcement in one component of a multiple schedule results in an increase in responding in an unchanged component of the schedule. Here we discuss a possible fourth kind of contrast that we call within‐trial contrast because within a discrete trial, the relative value of an event has an inverse effect on the relative value of the reinforcer that follows. We show that greater effort, longer delay to reinforcement, or the absence of food all result in an increase in the preference for positive discriminative stimuli that follow (relative to less effort, shorter delay, or the presence of food). We further distinguish this within‐trial contrast effect from the effects of delay reduction. A general model of this form of contrast is proposed in which the value of a primary or conditioned reinforcer depends on the change in value from the value of the event that precedes it.
CONTEXTUAL CONTROL BY FUNCTION AND FORM OF TRANSFER OF FUNCTIONS
Authors: Perkins David R. , Dougher Michael J. , Greenway David E.
Published: February 2008

This study investigated conditions leading to contextual control by stimulus topography over transfer of functions. Three 4‐member stimulus equivalence classes, each consisting of four (A, B, C, D) topographically distinct visual stimuli, were established for 5 college students. Across classes, designated A stimuli were open‐ended linear figures, B stimuli were circular, C stimuli three‐sided, and D stimuli four‐sided. Three different computer tasks then were trained with the B stimuli. Differential reinforcement and punishment procedures were then used to establish control over function transfer by the topography of the class members. For Task 1, function transfer, responding to C and D stimuli as subjects had to B stimuli, was reinforced. For Task 2, function transfer was reinforced for C stimuli but punished for D stimuli. For Task 3, function transfer was punished for both C and D stimuli. New equivalence classes were then established and tests for generalized contextual control were presented. All 5 subjects showed generalized contextual control of transfer of functions by stimulus topography. Implications of contextual control over function transfer in natural settings are discussed.
Identification of the sources of Escherichia coli in a watershed using carbon-utilization patterns and composite data sets
Authors: Moussa Samir H. , Massengale Rene D.
Published: February 2008

The field of bacterial source tracking (BST) has been rapidly evolving to meet the demands of water pollution analysis, specifically the contamination of waterways and drinking water reservoirs by point source and nonpoint source pollution. The goal of the current study was to create a BST library based on carbon-utilization patterns (CUP) for predicting sources of E. coli in a watershed, to compare this library to an antibiotic-resistance analysis (ARA) library previously published for the same isolates, and to determine the efficacy of using a composite dataset which combines data from both datasets into a single library for predicting the source of unknown isolates. This was accomplished by generating a CUP dataset and a composite ARA-CUP dataset for the E. coli isolates from known fecal sources within a watershed. These libraries were then used to predict the sources of E. coli isolates collected from 13 water sites in the same watershed and compared in regard to predictive accuracy. The dominant sources of E. coli in the South Bosque watershed were cattle as identified by all three methods. The 6-source composite library had higher average rates of correct classification (96.7%), specificity (99.2%), positive-predictive value (99.1%), and negative-predictive value (96.8%) than either the ARA or CUP 6 source libraries (ARCC 80.1% and 86.7% respectively). The current study is the first field study to compare two phenotypic methods, Antibiotic Resistance Analysis (ARA) and Carbon Utilization Profiling (CUP). This study is also the first to combine both of these methods to create a composite “toolbox” type approach.
Phosphorus recovery from wastewater through struvite formation in fluidized bed reactors: a sustainable approach
Authors: Bhuiyan M. I. H. , Mavinic D. S. , Koch F. A.
Published: February 2008

Recovery of phosphate as struvite (MgNH4PO4·6H2O), before it forms and accumulates on wastewater treatment equipment, solves wastewater treatment problems and also provides environmentally sustainable, renewable nutrient source for the agriculture sector. A pilot-scale fluidized bed reactor was used to recover phosphate through crystallization of struvite, from anaerobic digester centrate at the Lulu Island Wastewater Treatment Plant, Richmond, British Columbia, Canada. The desired degree of phosphate removal was achieved by maintaining operating pH (8.0–8.2), and recycle ratio 5–9, to control the supersaturation conditions inside the reactor. The performance of the system was found to be optimal when in-reactor supersaturation ratio was 2–6. Among several other operating parameters, apparent upflow velocity and magnesium to phosphate molar ratio were also found important to maintain system performance, both in terms of efficiency of phosphate removal and recovery as struvite pellets. A narrow window of upflow velocity (400–410 cm/min) was found to be effective in removing 75–85% phosphate. TOC level inside the rector was found to affect the performance to some extent. The precipitation potential of struvite could be successfully predicted using a thermodynamic solubility product value of 10−13.36 and its temperature dependence in PHREEQC.
Improving the assessment of risk from pathogens in biosolids: fecal coliform regrowth, survival, enumeration, and assessment
Authors: Dentel S. K. , Qi Y. , Herson D. S.
Published: February 2008

Reactivation or regrowth of fecal coliform bacteria in biosolids has recently become a concern due to knowledge that Class B materials may fail to meet this criterion after storage or even after land application. In this paper, data show the two types of fecal coliform increases that have been characterized: immediate reappearance of large concentrations directly after dewatering; and the rapid, but less immediate, increases that follow dewatering with some biosolids after dewatering. The latter phenomenon is shown to extend over a time period of days prior to gradual decrease in fecal coliform numbers. Modeling shows that anaerobic or fermentative growth cannot simulate the observed growth, but that a straightforward biokinetic model can duplicate the observed conditions if a doubling time of one hour is assumed, which is supported by literature. Thus regrowth cannot be ruled out as the underlying phenomenon
Beneficial reuse of precast concrete industry sludge to produce alkaline stabilized biosolids
Authors: Gowda C. , Seth R. , Biswas N.
Published: February 2008

The precast concrete industry generates waste called concrete sludge during routine mixer tank washing. It is highly alkaline and hazardous, and typically disposed of by landfilling. This study examined the stabilization of municipal sewage sludge using concrete sludge as an alkaline agent. Sewage sludge was amended with 10 to 40% of concrete sludge by wet weight, and 10 and 20% of lime by dry weight of the sludge mix. Mixes containing 30 and 40% of concrete sludge with 20% lime fulfilled the primary requirements of Category 1 and 2 (Canada) biosolids of maintaining a pH of 12 for at least 72 hours. The heavy metals were below Category 1 regulatory limits. The 40% concrete sludge mix was incubated at 52 °C for 12 of the 72 hours to achieve the Category 1 and 2 regulations of less than 1000 fecal coliform/g solids. The nutrient content of the biosolids was 8.2, 10 and 0.6 g/kg of nitrogen, phosphorus and potassium respectively. It can be used as a top soil or augmented with potassium for use as fertilizer. The study demonstrates that concrete sludge waste can be beneficially reused to produce biosolids, providing a long-term sustainable waste management solution for the concrete industry
Reductive dechlorination of 1, 2-dichloroethane using anaerobic sequencing batch reactor (ASBR)
Authors: Gupta S. K. , Mali S. C.
Published: February 2008

The objective of this research was to study the dechlorination of 1,2-dichloroethane (1,2-DCA) in a synthetic wastewater with lab-scale anaerobic sequencing batch (ASBR) reactors. Anaerobic sludge was used as a biocatalyst. Sodium acetate and dextrose served as the main methanogenic substrate. Experimental studies were conducted at wide-range of volumetric (0.25–1.25 g COD/L.d) and specific (0.0362–0.181 g COD/ g VSS.d) loading rates and influent wastewater CODs (500–2500 mg/L). During 266 days of reactor operation, the mixed culture degraded 1,2 dichloroethane at concentrations of up to 50 mg/L, with an HRT of 48 hrs. No chlorinated intermediates or residues were found. 1,2-DCA degradation resulted in ethene and ethane formation. Acetate was the most effective electron donor for dechlorination, although, dextrose was also effective, but to a lesser extent. The mixed culture degraded 1,2 Dichloroethane in the temperature range of 28±4 °C, with the pH range of 7.25 to 7.95. The 1,2-DCA removal rates achieved, and the safe nature of the end products, signify the anaerobic sequencing batch (ASBR) reactor technology for practical decontamination of waters containing such types of organochlorines. The COD removal efficiencies were in the range of 95 to 98% depending on volumetric and specific loading rates applied.
The performance and microbial diversity of temperature-phased hyperthermophilic and thermophilic anaerobic digestion system fed with organic waste
Authors: Lee M. Y. , Cheon J. H. , Hidaka T. , Tsuno H.
Published: February 2008

The objective of this study was to evaluate the performances and microbial diversities for development of the effective hyperthermophilic digester system that consists of a hyperthermophilic reactor and hyperthermophilic or thermophilic reactor in series. Lab-scale reactors were operated continuously fed with artificial kitchen garbage. The effect of temperature on the acidification step was firstly investigated. Results indicated that 20.8% of COD solubilization was achieved at 70°C, with 12.6% at 80°C. The average protein solubilization reached 31% at 80°C. Methane conversion efficiency following the acidification was around 85% on average at 55°C, but decreased with increasing temperature and methane gas was not produced over 73°C. As well, bacteria affiliated with the methanogens dominated the population below 65°C, while those affiliated with acidogens were predominant over 73°C. These results indicated that the hyperthermophilic process has considerable benefits to treat wastewater or waste containing high concentration of protein.
Building a Social and Motivational Framework for Understanding Satisfaction in Online Learning
Authors: Lin Yi-Mei , Lin Guan-Yu , Laffey James M.
Published: February 2008

This study examines how social and motivational attributes may influence students' online learning experiences. Based on a review of social theories of learning and research about individual characteristics associated with motivation four constructs were included: social ability, learning goal orientation, perceived task value, and self-efficacy. A model was generated to depict the dynamic relationships among these constructs and the outcome measure of learning satisfaction. Factor analyses highlight four dimensions of social ability: social presence-students, social presence-instructors, social navigation, and written communication skills. The results of applying structural equation modeling to data from a sample of 110 online students show the importance of students' perceived task value, self efficacy, and social ability for satisfaction in online learning.
Effectiveness of Interactive Online Algebra Learning Tools
Authors: Cavanaugh Cathy , Gillan Kathy Jo , Bosnick Jan , Hess Melinda , Scott Heather
Published: February 2008

This study of student performance in an online Algebra course looked at the development, implementation, and evaluation of interactive tools for graphing linear equations. The study focused on an interactive tool that was evaluated with virtual school Algebra students for a challenging component of the course. The performance of these students in the course on the component was compared to the performance of students who did not use the intervention. The performance of students learning in the online course with the interactive tools was equivalent to that of not using the tools. The implications of the unique nature of the online Algebra course for teacher preparation are discussed.
Immunosuppression-Related Fibroproliferative Polyps: A Substantial Subset of Acquired Pediatric Mucocutaneous Polyps
Authors: Gleason Briana C. , Vargas Sara O.
Published: February 2008

A distinct group of fibroproliferative polyps of the tongue arising in immunosuppressed children and often associated with chromosomal breakpoints at chromosomes 9p34 or 22q11 was recently described. Based on this finding, we reviewed fibroepithelial polyps arising in nonlingual sites in the pediatric population to investigate a possible relationship with immunosuppression. We identified 8 fibroepithelial polyps arising in 6 immunosuppressed patients (4 males and 2 females, median age 17 years) in a wide range of mucocutaneous sites. Histologic features were identical to the common fibroepithelial polyp, or skin tag, with a variably collagenous fibrovascular core covered by unremarkable squamous epithelium. No viral cytopathic changes were identified in any case. Although cytogenetic studies were not performed on any of the biopsy material, 1 patient had a constitutional deletion of chromosome 22q11. We suggest that there may be a relationship between these polyps and the previously described tongue lesions and that immunosuppression may be an important factor in their pathogenesis.
Characterization of Chorioamnionitis in 2nd-Trimester C-Section Placentas and Correlation with Microorganism Recovery from Subamniotic Tissues
Authors: Hecht Jonathan L. , Onderdonk Andrew , Delaney Mary , Allred Elizabeth N. , Kliman Harvey J. , Zambrano Eduardo , Pflueger Solveig M. , Livasy Chad A. , Bhan Ina , Leviton Alan
Published: February 2008

Prolonged exposure to infection appears to influence fetal/neonatal development. We characterize the relationship between histologic patterns of inflammation and microorganism recovery from the placentas of live born infants delivered before the 28th postmenstrual week. The subamniotic parenchyma of 835 placentas delivered by cesarean section were cultured and evaluated for specific histologic patterns of inflammation in a blinded fashion. Cases with prolonged membrane rupture were excluded. Microorganisms were recovered from 41% of placentas. Microorganisms found more frequently in placentas with high-grade chorionic plate inflammation include Actinomyces, Prevotella bivia, Corynebacterium sp., Escherichia coli, Peptostreptococcus magnus, multiple species of Streptococci, and Mycoplasma sp., including Ureaplasma urealyticum. These microorganisms were also associated with fetal vasculitis (neutrophilic infiltration of chorionic plate stem vessels or umbilical cord). Recovery of microorganisms from placental parenchyma is associated with histologic inflammation. The same microorganisms responsible for inciting high-grade chorionic plate inflammation are also most likely to promote fetal inflammation.
Comparison of canine capillary and jugular venous blood lactate concentrations determined by use of an enzymatic-amperometric bedside system
Authors: Ferasin Luca , Nguyenba Thaibinh P.
Published: February 2008

Objective—To evaluate the analytical agreement between blood lactate concentrations determined by use of an enzymatic-amperometric bedside system in capillary blood samples from the pinna and in jugular venous blood samples from dogs.

Animals—53 dogs.

Procedures—For each dog, venous and capillary blood samples were obtained from a jugular vein and from the ear pinna (by use of a lancing device), respectively, following a randomized sequence of collection. Lactate concentrations in both types of samples were analyzed by use of an enzymatic-amperometric bedside system intended for lactate detection in capillary blood samples from humans that was previously validated in dogs. The Passing-Bablock regression analysis was used to compare venous and capillary blood lactate concentrations; the level of agreement was calculated by use of the Bland-Altman method.

Results—Jugular venous blood samples were collected without difficulty from all 53 dogs. A capillary blood sample was obtained from only 47 dogs. The correlation coefficient between lactate concentrations measured in venous and capillary blood samples was 0.58 (slope, 2.0 [95% confidence interval, 1.5 to 3.0]; intercept, −1.2 [95% confidence interval, −3.1 to 0.4]). The mean difference between methods was 0.72 mmol/L (95% confidence interval, 0.38 to 1.06) with limits of agreement of −1.55 to 2.99 mmol/L.

Conclusions and Clinical Relevance—Because of the lack of agreement between lactate concentrations determined in capillary and jugular venous blood samples, measurement of capillary blood lactate concentration in dogs performed with the technique used in the study does not appear to be a reliable alternative to jugular venous blood measurements.
Statistical relevance of ultrasonographic criteria in the assessment of diffuse liver disease in dogs and cats
Authors: Feeney Daniel A. , Anderson Kari L. , Ziegler Laura E. , Jessen Carl R. , Daubs Brian M. , Hardy Robert M.
Published: February 2008

Objective—To determine whether objectively applied ultrasonographic interpretive criteria are statistically useful in differentiating among 7 defined categories of diffuse liver disease in dogs and cats.

Sample Population—Ultrasonographic images of 229 dogs and 104 cats.

Procedures—Liver parenchymal or related sonographic criteria established by the authors were retrospectively and independently applied by 3 radiologists who were not aware of patient status or patient laboratory data. Seven histologic or cytologic categories of diffuse (infiltrative but not nodular) liver diseases were jointly established by the authors and included normal liver; inflammation; round-cell neoplasia; non–round-cell infiltrative, prenodular (early) metastatic neoplasia; lipidosis; vacuolar hepatopathy; and other. Liver parenchymal sonographic criteria included parenchymal sound attenuation with increasing depth, comparative organ echogenicity (liver, spleen, and kidneys), diffuse or patchy hyperechoic or hypoechoic echotexture, uniform or coarse echotexture, portal venous clarity, and liver lobe geometry. Related extrahepatic criteria included gallbladder wall thickness, bile duct diameter, amount and character of gallbladder precipitate, nondependent shadowing in the gallbladder, hepatic vein diameter versus caudal vena cava diameter, peritoneal fluid, spleen echotexture (normal vs abnormal [characterized]), and kidney echotexture. Ultrasonographic criteria were statistically compared to the 7 categories of diffuse liver disease in search of clinically exploitable relationships.

Results—Statistical evaluation of the applied ultrasonographic criteria did not yield clinically acceptable accuracy for discrimination among the 7 categories of diffuse liver diseases (including normal liver) in either species.

Conclusions and Clinical Relevance—Criterion-based ultrasonographic appearance was insufficient to discriminate among canine and feline diffuse infiltrative liver diseases.
Effect of topical ophthalmic application of cidofovir on experimentally induced primary ocular feline herpesvirus-1 infection in cats
Authors: Fontenelle Jennifer P. , Powell Cynthia C. , Veir Julia K. , Radecki Steven V. , Lappin Michael R.
Published: February 2008

Objective—To evaluate the efficacy of twice-daily ophthalmic application of 0.5% cidofovir solution in cats with experimentally induced primary ocular feline herpesvirus-1 (FHV-1) infection.

Animals—Twelve 6-month-old sexually intact male cats.

Procedures—Cats were randomly assigned to either a treatment or control group. Ocular infection with FHV-1 was induced (day 0) in all cats via inoculation of both eyes with 104 plaque-forming units of a plaque-purified FHV-1 field strain. Twice daily for 10 days beginning on day 4 after virus inoculation, the treatment group received 1 drop of 0.5% cidofovir in 1% carboxymethylcellulose in both eyes, and the control group received 1 drop of 1% carboxymethylcellulose in both eyes. A standardized scoring method was used to evaluate clinical signs of FHV-1 infection in each cat once daily for 24 days. The amount of ocular viral shedding was assessed by use of a quantitative real-time PCR procedure every 3 days during the study period. Clinical scores and viral quantification were averaged over the pretreatment (days 0 to 3), treatment (days 4 to 14), and posttreatment (days 15 to 24) periods for each cat.

Results—During the treatment period, clinical scores and amount of viral ocular shedding were significantly lower in the treatment group, compared with findings in the control group.

Conclusions and Clinical Relevance—Twice-daily application of 0.5% cidofovir solution in both eyes significantly decreased the amount of viral shedding and the severity of clinical disease in cats with experimentally induced ocular FHV-1 infection.
Adverse effects and outcome associated with dexamethasone administration in dogs with acute thoracolumbar intervertebral disk herniation: 161 cases (2000–2006)
Authors: Levine Jonathan M. , Levine Gwendolyn J. , Boozer Lindsay , Schatzberg Scott J. , Platt Simon R. , Kent Marc , Kerwin Sharon C. , Fosgate Geoffrey T.
Published: February 2008

Objective—To determine complications and neurologic outcomes associated with dexamethasone administration to dogs with surgically treated thoracolumbar intervertebral disk herniation, compared with dogs not receiving dexamethasone.

Design—Retrospective case series.

Animals—161 dogs with surgically confirmed thoracolumbar disk herniation.

Procedures—Medical records from 2 hospitals were used to identify dogs that had received dexamethasone < 48 hours prior to admission (dexamethasone group dogs), dogs that received glucocorticoids other than dexamethasone < 48 hours prior to admission (other-glucocorticoid group dogs), and dogs that received no glucocorticoids (nontreatment group dogs). Signalment, neurologic injury grade, laboratory data, and complications were extracted from medical records.

Results—Dexamethasone group dogs were 3.4 times as likely to have a complication, compared with other-glucocorticoid or nontreatment group dogs. Dexamethasone group dogs were 11.4 times as likely to have a urinary tract infection and 3.5 times as likely to have diarrhea, compared with other-glucocorticoid or nontreatment group dogs. No differences in neurologic function at discharge or recheck evaluation were detected among groups.

Conclusions and Clinical Relevance—Results indicated that treatment with dexamethasone before surgery is associated with more adverse effects, compared with treatment with glucocorticoids other than dexamethasone or no treatment with glucocorticoids, in dogs with thoracolumbar intervertebral disk herniation. In this study population, no difference in outcome was found among groups. These findings suggest that the value of dexamethasone administration before surgery in dogs with thoracolumbar disk herniation should be reconsidered.
Relationships between Culture and Health Status: A Multi-Site Study of the Older Chinese in Canada
Authors: Lai Daniel W.L. , Tsang Ka Tat , Chappell Neena , Lai David C.Y. , Chau Shirley B.Y.
Published: February 2008

This study examined the relationships between culture and the health status of older Chinese in Canada. Data were collected through face-to-face interviews with a cross-sectional, randomly selected sample of 2,272 older Chinese between 55 and 101 years of age in seven Canadian cities. Health status was assessed by the number of chronic illnesses, by limitations in ADL and IADL, and by information on the Medical Outcome Study Short Form SF-36. Although cultural variables explained only a small proportion of variance in health status, having a stronger level of identification with traditional Chinese health beliefs was significant in predicting physical health, number of illnesses, and limitations on IADL. Other cultural variables, including religion, country of origin, and length of residence in Canada, were also significant in predicting some health variables. Interventions to improve health should focus on strategies to enhance cultural compatibility between users and the health delivery system.
Housing and Living Arrangements of South Asian Immigrant Seniors in Edmonton, Alberta
Authors: Ng Cheuk Fan , Northcott Herbert C. , Abu-Laban Sharon McIrvin
Published: February 2008

The Canadian population is aging and becoming more ethnically diverse. This paper focuses on South Asian immigrant seniors and examines differences in housing and living arrangements among seniors who immigrated at different life stages. We interviewed a convenience sample of 161 immigrant seniors of South Asian descent in Edmonton, Alberta, to assess type of living arrangement, type of housing anddwelling density(measured in persons per room), activity in the neighbourhood, and means of transportation. Overall, those seniors who came to Canada before the end of mid-life were more likely than those who came at an older age to drive a car and, if married, to live in a one- or two-generation family. Women were more likely than men to be widowed, have poorer English-language skills, or live with a three-generation family if unmarried, and less likely to drive a car. Most respondents were satisfied with their living arrangements, housing, and perceived safety at home and in their neighbourhood. Theoretical implications are discussed.
Caregiver Acceptance of Adverse Effects and Use of Cholinesterase Inhibitors in Alzheimer's Disease
Authors: Oremus Mark , Wolfson Christina , Vandal Alain C. , Bergman Howard , Xie Qihao
Published: February 2008

Caregivers play a determining role in choosing treatments for persons with Alzheimer's disease. The objective of this study was to examine caregivers' willingness to have persons with Alzheimer's disease continue taking cholinesterase inhibitors in the event that any 1 of 11 adverse effects was to occur. Data were gathered via postal questionnaire from 375 caregivers in Montreal. Sixty-four per cent of caregivers responded (n = 201), and most (≥59%) were willing to continue treatment if persons with Alzheimer's disease suffered from weight loss or loss of appetite. However, most (≥53%) were not willing to continue treatment in the event of headache, dizziness, nausea, diarrhea, vomiting, drop in blood pressure, insomnia, muscle cramps, or stomach bleeding. The use of cholinesterase inhibitors by persons with Alzheimer's disease was positively associated with caregivers' willingness to accept greater numbers of adverse effects (adjusted relative risk = 1.97; 95% CI = 1.11 to 3.61). Caregivers appear to make a risk–benefit assessment when they decide whether or not care-recipients should continue pharmacotherapy in the event of adverse effects.
L'utilisation des services de centre de jour par les personnes âgées qui présentent des incapacités
Authors: Savard Jacinthe , Leduc Nicole , Lebel Paule , Béland François , Bergman Howard
Published: February 2008

This study consists of a secondary analysis of data collected during the SIPA demonstration project. Its purpose is to identify the proportion of Adult Day Care (ADC) users as well as the determinants of use in this group of persons 65 years old and over receiving home care services in Montreal. Results show that 18.8% of the sample have at least one ADC presence during a 6 months study period. The following factors increase the probability of ADC use: being younger; not having a university degree; being born outside of Canada or for persons born in Canada, living with a caregiver; receiving help from the CLSC for daily life activities more than once a week; being in the catchment population of an ADC which fees are lower; and for men only, having had a stroke or presenting more functional incapacities.
Crash Prediction Models for Intersections on Rural Multilane Highways
Authors: Jonsson Thomas , Ivan John N. , Zhang Chen
Published: February 2008

Accident prediction models are often used to estimate the number of accidents on segments and at intersections in the road network. Most often the models are developed for a total number of crashes for the facility or for crashes by severity. However, the frequency and severity of crashes of different types can be expected to vary according to underlying phenomena that cause them. To account for this variation better, modeling of accidents at intersections on rural four-lane highways in California is described separately for four different collision types: opposite-direction crashes, same-direction crashes, intersecting-direction crashes, and single-vehicle crashes. The findings from this modeling are reported with a special focus on the differences in crash types by (a) severity distribution, (b) dependence on traffic flow, and (c) variables that best explain between-site variations in the occurrence of different crash types. Evident differences exist in severity as well as the relationship of flow between several of the crash types. Intersecting and opposite-direction crashes are more severe than same-direction crashes. Same- and opposite-direction crashes exhibit similar relationships with traffic flow, but there are differences compared with intersecting-direction crashes and single-vehicle crashes. In addition, the variables that turn out to be good predictor variables differ somewhat for each crash type.
Relationships between Crash Involvement and Temporal-Spatial Driving Behavior Activity Patterns
Authors: Jun Jungwook , Ogle Jennifer , Guensler Randall
Published: February 2008

Knowledge about characteristics of crash-involved drivers and their driving performance can enhance countermeasure programs designed to improve safety on roadways. However, few studies have been able to analyze detailed exposure data of individual drivers (travel by time of day and by roadway type) alongside driving performance data (speed, throttle, braking, and acceleration). Thus, researchers have been forced to base safety analyses on aggregate crash experience rather than on more frequent individual driving activities and driving performance parameters. This research evaluated driving exposure and performance differences between drivers who were involved in crashes versus drivers who were not involved in crashes during a 14-month study period, on the basis of data for vehicles with Global Positioning Systems. The objective was to verify whether the exposure of crash-involved drivers and driving performance were significantly different on the basis of disaggregated analyses by facility types and trip start times. Researchers found that the mileage exposure, speed, and acceleration patterns of drivers who were involved in crashes during the study period were significantly different from those of drivers who were not involved in crashes. Further, crash-involved drivers accumulated more mileage, consistently traveled at higher speeds, and engaged more frequently in hard deceleration events than their no-crash counterparts did. Although this study does not definitively correlate driver exposure and performance measures with crash causation, it does suggest that there is real potential to identify at-risk drivers on the basis of data obtained from vehicle-monitoring technologies. The identification and immediate correction of at-risk behaviors could obviate crash experience. If this research is successful, the surrogate measures also would reduce safety analysts' dependency on crash data.
Comparison of Two Unconventional Intersection Schemes
Authors: Esawey Mohamed El , Sayed Tarek
Published: February 2008

The operational performance of signalized intersections can be significantly affected by heavy left-turn movements. Therefore, several measures to improve the performance of intersections with heavy left-turn movements, including some unconventional schemes, have been investigated. In this paper the performance of two of these unconventional schemes, namely, the crossover displaced left-turn (XDL) intersection and the upstream signalized crossover (USC) intersection, is compared. The XDL intersection eliminates left-turn opposing conflicts by displacing the left-turn lane to the opposing direction and crossing the left-traffic to the left side of the road before the intersection. The USC intersection eliminates left-turn opposing conflicts by crossing both the left and through traffic to the left side of the road before the intersection. The microsimulation software VisSim was used to analyze the two unconventional intersections for comparison. The analysis showed that the XDL outperforms the conventional intersection under various volume scenarios. In contrast, the USC outperforms the conventional intersection under moderate- and high-volume conditions or in the existence of extremely heavy left-turn movements. The results showed that the USC and the XDL exhibit similar average delays in low-, moderate-, and moderately high-volume conditions, with the XDL slightly outperforming the USC. However, the XDL significantly outperforms the USC under high-volume scenarios. The XDL has, as a basic design element, a left-turn bay that extends between the primary and the secondary intersections. The existence of this bay is probably the main reason for the high capacity of the XDL. Such an additional bay requires more right-of-way and higher construction costs than USC.
Parameters for Evaluation of Speed Differential
Authors: Bella Francesco
Published: February 2008

This paper describes the results of a study performed with the interactive fixed-base driving simulator of the Inter-University Research Center for Road Safety and seeks (a) to select, from the parameters proposed in the literature for the evaluation of the speed differentials between tangents and curves, those that best reflect the real speed reductions experienced by drivers and (b) to develop new models for estimating speed differential values. Thirty people drove the driving simulator on a two-lane rural road with 16 different tangent-curve configurations. On the basis of measured speeds, the parameters were calculated for the 85th-percentile of the distribution of maximum speed reduction experienced by each driver (85MSR) as well as the differential speed not exceeded by 85% of the drivers traveling under free-flow conditions (Δ85V). The statistical analysis performed reveals that the differences between the two parameters were statistically significant and, in so doing, indicates that using Δ85V to measure speed differentials leads to an underestimation of the speed differences adopted by drivers. Three speed differential predicting models were also developed. The models being proposed are similar to those in the literature. These models show that speed differentials are influenced by the same variables that were uncovered in previous field research. The results of the present study corroborate the outstanding potential of the driving simulator as a useful instrument for the analysis of speeds on two-lane rural roads as well as for the effects of road alignment configurations on drivers.
Seemingly Unrelated Regression Model of Car Speeds and Speed Deviations in Freeway Work Zones
Authors: Porter Richard J. , Mahoney Kevin M. , Mason John M.
Published: February 2008

Current work zone design and traffic control guidance is based heavily on desirable speed-related outcomes, but knowledge concerning actual speed-related outcomes of design and traffic control decisions is limited. The objective of this research is to investigate relationships between speed behavior, roadway and roadside geometrics, and traffic control in work zones. The objective is accomplished through specification and estimation of a seemingly unrelated regression (SUR) model. The dependent variables modeled were 85th-percentile passenger car speed and standard deviation of passenger car speed. Work zone design and traffic control features were investigated as explanatory variables. Speed and infrastructure data used for estimation were collected in Pennsylvania and Texas work zones. The SUR model accounted for contemporaneous correlations of the disturbance terms in the two speed equations. In the equation for 85th-percentile speed, regression parameters were statistically significant for variables representing work zone configuration, type of roadway infrastructure, work zone location, distance traveled from the beginning of the work zone, posted speed limit, vertical alignment, and total paved cross-section width. In the equation for standard deviation of speed, parameters were statistically significant for variables representing distance traveled from the beginning of the work zone, total paved cross-section width, and reduction in posted speed and roadside conditions. Several recommendations for future work are provided, including expansion of the system of equations to include 85th-percentile truck speeds and standard deviation of truck speeds and consideration of possible contemporaneous relationships between speed measures.
Relationship of Lane Width to Safety on Urban and Suburban Arterials
Authors: Potts Ingrid B. , Harwood Douglas W. , Richard Karen R.
Published: February 2008

This research investigated the relationship between lane width and safety for roadway segments and intersection approaches on urban and suburban arterials. The research found no general indication that the use of lanes narrower than 3.6 m (12 ft) on urban and suburban arterials increases crash frequencies. This finding suggests that geometric design policies should provide substantial flexibility for use of lane widths narrower than 3.6 m (12 ft). The inconsistent results suggested increased crash frequencies with narrower lanes in three specific design situations. Narrower lanes should be used cautiously in these three situations unless local experience indicates otherwise.
Determination of Storage Lengths of Left-Turn Lanes at Signalized Intersections
Authors: Qi Yi , Yu Lei , Azimi Mehdi , Guo Lei
Published: February 2008

A new method has been developed for estimating the storage lengths of left-turn lanes at signalized intersections. To prevent lane overflow, the left-turn lane should be designed to have a length sufficient to store the longest expected queue. In this study, the left-turn queue length was estimated by considering two factors: (a) vehicles that arrive during the red phase and (b) the queue of vehicles carried over from previous cycles. A method based on the discrete-time Markov chain was applied to model the leftover queue length at the end of the green phase. A case study was provided to demonstrate the application of the proposed model. In the model evaluation, the estimated left-turn queue lengths were compared with field observations and estimates from other existing methods. The results showed that the proposed model significantly outperformed existing methods by providing more accurate estimates of the lengths of left-turn queues.
Observed Distribution Patterns of On-Ramp Merge Lengths on Urban Freeways
Authors: Yi Hanwen , Mulinazzi Thomas E.
Published: February 2008

Three on-ramp sites with moderate to high volumes of through and merge traffic along I-35 within the greater Kansas City, Kansas and Missouri, metropolitan area were selected for investigation of the distribution patterns of the merge lengths of ramp vehicles. On the basis of the observed merging behaviors, merge vehicles were categorized into three types: free merge (FM), challenged merge (CM), and platoon merge (PM). The field data were analyzed with specifically developed software. The results show that (a) FM vehicles merge onto a freeway at arbitrary locations, (b) CM vehicles require traveling a longer distance before a safe merge, and (c) PM vehicles follow a natural smooth path and force themselves onto the mainline traffic within a certain area of a merge lane. The 85th-percentile merge length of all ramp vehicles was further observed to be related to the CM volume, the PM volume, and the average speed of the freeway right-hand first lane. Finally, the potential applications of these findings were discussed, with an example illustrating how to use the 85th-percentile merge length to determine the minimum merge lane length for an urban freeway on-ramp.
System-Optimal Stochastic Transportation Network Design
Authors: Patil Gopal R. , Ukkusuri Satish V.
Published: February 2008

In transportation engineering, the network design problem (NDP) aims at finding an optimal link improvement in a network for given demand. Although traffic demand is essentially uncertain, many previous studies assumed it to be deterministic. The demand stochasticity is incorporated and formulas are developed for system-optimal (SO) flow stochastic NDP. The SO assumption is justified by comparing results from SO deterministic NDP with those of user-equilibrium NDP. The difference in social cost between the two approaches is found to be less than 5%. Two two-stage stochastic programs with recourse formulations are proposed: one with penalty function and the other without. The main advantage of the first formulation is that a planner can exert better control on improvement by appropriately weighing reduction in the congestion versus improvement costs. The challenge, however, lies in selecting an appropriate penalty function. A nonlinear penalty function is found suitable for the test network studied. The second formulation does not require penalty function but results in a large number of scenarios. Nonanticipativity constraints are introduced in the second formulation to arrive at uniform improvement over all scenarios. Both formulations are solved on a test network. It is found that necessary improvements and the total costs with both models are more than those for average demand.
Dynamic Cell Transmission–Based Pedestrian Model with Multidirectional Flows and Strategic Route Choices
Authors: Asano Miho , Sumalee Agachai , Kuwahara Masao , Tanaka Shinji
Published: February 2008

This paper proposes a framework for a dynamic pedestrian model with a strategic route choice model and multidirectional flow propagation. In an open urban area, a massive number of possible pedestrian paths can be defined. However, psychologically the pedestrian does not consider all these paths as distinct options. Thus, this paper assumes the pedestrian chooses a series of consecutive subareas to traverse in the first instance. Then, the model allocates the actual flows on each detailed route on the basis of an assumption of dynamic user optimum. Combining these two stages, the model assumes a hierarchical decision of pedestrians’ route choice. A modified cell transmission model (CTM) is adopted to represent the physical phenomena of dynamic propagation of the pedestrian flows. A key difference from the original CTM is that the pedestrian flow is multidirectional by nature. This paper proposes a modified CTM to consider the multidirectional movement. The proposed modified CTM is then assessed with a test case.