Showing papers by "University of Winnipeg published in 2008"

Intracerebral Hemorrhage Models in Rat: Comparing Collagenase to Blood Infusion:

Abstract: Many therapies have shown promise in preclinical stroke studies, but few benefit patients. A greater understanding of stroke pathophysiology is needed to successfully develop therapies, and this depends on appropriate animal models. The collagenase and blood infusion models of intracerebral hemorrhage (ICH) are widely used; yet, investigators often prefer using one model for a variety of reasons. Thus, we directly compared these to highlight advantages and limitations of each as well as the assessment approach. An ICH was created by infusing blood or bacterial collagenase into the rats' striatum. We matched initial hematoma volume in each model (Experiment 1) and assessed the time course of bleeding (Experiment 2). Functional deficits and the progression of injury were tracked over 6 weeks using behavior, magnetic resonance imaging, and histology (Experiment 3). Despite similar initial hematoma volumes, collagenase-induced ICH resulted in a greater blood-brain barrier breakdown and more damage to the striatum, substantia nigra, white matter, and cortex. Magnetic resonance imaging revealed faster hematoma resolution in the blood model, and little increase in the volume of tissue lost from 1 to 6 weeks. In contrast, tissue loss continued over 4 weeks in the collagenase model. Finally, functional deficits recovered more quickly and completely in the blood model. This study highlights key differences between these models and that neither closely replicates the human condition. Thus, both should be used whenever possible taking into account the significant differences between these models and their limitations. Furthermore, this work illustrates significant weaknesses with several outcome measures.

Light-toned salty soils and coexisting Si-rich species discovered by the Mars Exploration Rover Spirit in Columbia Hills

Abstract: [1] Light-toned soils were exposed, through serendipitous excavations by Spirit Rover wheels, at eight locations in the Columbia Hills. Their occurrences were grouped into four types on the basis of geomorphic settings. At three major exposures, the light-toned soils are hydrous and sulfate-rich. The spatial distributions of distinct types of salty soils vary substantially: with centimeter-scaled heterogeneities at Paso Robles, Dead Sea, Shredded, and Champagne-Penny, a well-mixed nature for light-toned soils occurring near and at the summit of Husband Hill, and relatively homogeneous distributions in the two layers at the Tyrone site. Aeolian, fumarolic, and hydrothermal fluid processes are suggested to be responsible for the deposition, transportation, and accumulation of these light-toned soils. In addition, a change in Pancam spectra of Tyrone yellowish soils was observed after being exposed to current Martian surface conditions for 175 sols. This change is interpreted to be caused by the dehydration of ferric sulfates on the basis of laboratory simulations and suggests a relative humidity gradient beneath the surface. Si-rich nodules and soils were observed near the major exposures of S-rich soils. They possess a characteristic feature in Pancam visible near-infrared (Vis-NIR) spectra that may be diagnostic of hydrated species, and this spectral feature can be used to search for additional Si-rich species. The exposures of hydrated salty soils within various geomorphic settings imply the potential existence of hydrous minerals in similar settings over a much wider area. Hydrous sulfates represent one of the candidates that may contribute the high level of water equivalent hydrogen in equatorial regions detected by the Neutron Spectrometer on Mars Odyssey.

Oleanolic acid and related derivatives as medicinally important compounds.

Abstract: Oleanolic acid has been isolated from chloroform extract of Olea ferruginea Royle after removal of organic bases and free acids. The literature survey revealed it to be biologically very important. In this review the biological significance of oleanolic acid and its derivatives has been discussed. The aim of this review is to update current knowledge on oleanolic acid and its natural and semisynthetic analogs, focussing on its cytotoxic, antitumer, antioxidant, anti-inflamatory, anti-HIV, acetyl cholinesterase, alpha-glucosidase, antimicrobial, hepatoprotective, anti-inflammatory, antipruritic, spasmolytic activity, anti-angiogenic, antiallergic, antiviral and immunomodulatory activities. We present in this review, for the first time, a compilation of the most relevant scientific papers and technical reports of the chemical, pre-clinical and clinical research on the properties of oleanolic acid and its derivatives.

The Effect of Weather on Consumer Spending

Abstract: There has been a great deal of anecdotal evidence to suggest that weather affects consumer decision making. In this paper, we provide empirical evidence to explain how the weather affects consumer spending and we detail the psychological mechanism that underlies this phenomenon. Specifically, we propose that the effect of weather – and, in particular, sunlight – on consumer spending is mediated by negative affect. That is, as exposure to sunlight increases, negative affect decreases and consumer spending tends to increase. We find strong support for this prediction across a series of three mixed methods studies in both the lab and the field. & 2010 Elsevier Ltd. All rights reserved.

An Efficient Algorithm for Answering Graph Reachability Queries

Abstract: Given a directed graph G, to check whether a node v is reachable from another node u through a path is often required. In a database system, such an operation is called a recursion computation or reachability checking and not efficiently supported. The reason for this is that the space to store the whole transitive closure of G is prohibitively high. In this paper, we address this issue and propose an 0(n2 + bnradic(b)) time algorithm to decompose a directed acyclic graph (DAG) into a minimized set of disjoint chains to facilitate reachability checking, where n is the number of the nodes and b is the DAG's width, defined to be the size of a largest node subset U of the DAG such that for every pair of nodes u, v isin U, there does not exist a path from u to v or from v to u. Using this algorithm, we are able to label a graph in 0(be) time and store all the labels in O(bn) space with O(logb) reachability checking time, where e is the number of the edges of the DAG. The method can also be extended to handle cyclic directed graphs. Experiments have been performed, showing that our method is promising.

Gain-based selection of ambient media services in pervasive environments

Abstract: Providing ambient media services in the pervasive environments is a challenging issue. This is due to the fact that users have different satisfaction level in using different media services in varying contexts. We address this issue by proposing a gain-based media service selection mechanism. Gain refers to the extent a media service is satisfying to a user in a particular context. In our proposed mechanism, the gain is dynamically computed by adopting a user-centered approach that includes user's context, profile, interaction history, and the reputation of a service. The dynamically computed gain is used in conjunction with the cost of using a service (e.g. media subscription and energy consumption cost) to derive our service selection mechanism. We adopt a combination of greedy and dynamic programming based solution to obtain a set of services that would maximize the user's overall gain in the ambient environment by minimizing the cost constraint. Experimental results demonstrate the potential of this approach.

The semicircular canal system and locomotion: The case of extinct lemuroids and lorisoids

Abstract: Paleontologists reconstruct the locomotor and postural behavior of extinct species by analogy with living forms and biomechanical analyses. In rare cases, behavioral evidence such as footprints can be used to confirm fossil-based reconstructions for predominantly terrestrial orders of mammals. For instance, the chalicothere prints from Laetoli show that these perissodactyls supported their body weight on the metacarpals, as previously reconstructed.1. Unfortunately, primates are mostly arboreal and rarely leave footprints. The cercopithecid and hominin prints at Laetoli are a rare exception. We have recently shown that the semicircular canal system can be used to test and augment locomotor reconstructions based on postcranial material or to provide first estimations of locomotor behavior for taxa not known from the postcranium. Using a sample of modern primates, we have been able to demonstrate that the radii of curvature of the semicircular canals are significantly correlated with both body mass and agility of locomotion.2 This paper reviews those results and examines the relationship between semicircular canal morphology and other evidence in efforts to reconstruct locomotor behavior in subfossil lemurs from the Holocene of Madagascar and fossil lorisoids from the Miocene of Africa. © 2008 Wiley-Liss, Inc.

Attracting Immigrants to Smaller Urban and Rural Communities: Lessons Learned from the Manitoba Provincial Nominee Program

Abstract: Low birth rates and population ageing have slowed population growth rates in Canada, and immigration has become the primary driver of population and labour force growth in the nation. The distribution of new arrivals to Canada, however, has been concentrated in a few major cities. Until recently, Montreal, Toronto and Vancouver have been the destination of approximately 75% of all immigrants. All orders of government have introduced policies and programs to influence the regional distribution of immigrants across the country, ostensibly so that the benefits of immigration will be more evenly shared on a national basis. An assessment of the Manitoba Provincial Nominee Program helps identify policy and program initiatives and best practices effective in changing the regional distribution of immigrants and attracting more new arrivals to smaller urban and rural communities.

Greater sciatic notch as a sex indicator in juveniles

Abstract: Using Schutkowski's method for juvenile sex determination (Schutkowski H. 1993. Am J Phys Anthropol 90:199-205), we evaluated the morphology of the greater sciatic notch of 56 ilia (23 females and 33 males) from a documented skeletal collection housed at the Bocage Museum in Lisbon (Portugal). After applying Schutkowski's original methodology and comparing the results with previous studies, we used age-adjusted metrical variables to describe greater sciatic notch depth, breadth, and angle. Although results of both morphological and metrical analyses did not reveal a statistically significant level of sexual analyses dimorphism, we found a strong correlation between pelvic morphology and age at death. On the basis of the obtained results, we argue that Schutkowski's morphological method does not predict sex accurately in all populations and that recorded correlation of iliac features with age needs to be further explored in the context of the ontogeny of sexual dimorphism.

Isolation of Faults in Distribution Networks With Distributed Generators

Abstract: This paper presents an agent-based protection scheme for distribution networks with distributed generators. The distribution network is divided into several network segments. The relay agents, which are located at the boundaries of these segments, can determine the direction of fault currents using the transients generated by the fault. Fault directions determined by the relay agents located at different points of the network are combined to determine the faulted segment. A fault direction identification technique, which uses the wavelet coefficient of the measured line currents, was developed for relay agents. The performance of the proposed protection scheme is investigated through simulation of a benchmark medium-voltage distribution system.

Teleophthalmology screening for diabetic retinopathy through mobile imaging units within Canada.

Abstract: Background: This study aimed to describe and measure the health results of a Category 3 teleophthalmology screening project for diabetic retinopathy (DR). Implemented through mobile screening imaging units located within pharmacies, the project had the goal of reaching unscreened diabetic patients in urban communities while lowering barriers to screening and saving medical resources. Methods: Image capture of both eyes of 3505 known diabetic individuals was performed in the provinces of Quebec, British Columbia, Alberta, Manitoba, and Saskatchewan. A photographer performed fundus imaging, and a nurse used mild pupil dilation only when necessary to secure image quality. Screening was provided free of cost in the context of DR health days for DR screening. Through teleophthalmology, ophthalmologists proceeded with data and image interpretation, and timely referral when indicated. Results: This project allowed the resumption of screening of over 38% of the cohort of known diabetics who reported never having undergone any eye examination with pupil dilation, and an additional 30% who reported not having been examined for over 2 years. All known diabetics were under the care of a general physician, and their mean diabetes duration, when known, was 8 years. DR pathology was found in 22.5% (20%–28%) of the cohort, 1.8% requiring urgent referral (within 30 days) as a result of the severity of the DR and 0.6% (0%–l.8%) requiring urgent referral for other reasons. An additional 8.7% (8.1%–19.5%) required ophthalmologic attention within 6 months because of DR and another 2.0% (0%–6.3%) between 6 months and I year. Incidental findings were found in 23%, the majority of which were related to cataract and dry macular degeneration. Urgent or significant incidental findings were found in 0.6% of the screened eyes. Pupil dilation with tropicamide 1% was deemed useful or necessary in 33.7% of the cohort. For 0.7% of the cohort, the images could not be interpreted because of poor image quality and for that reason had to be referred for a traditional dilated eye examination. Ophthalmologists were relieved of the examination of 85.6% of the screened diabetic individuals who benefited from screening without requiring a traditional ophthalmologic examination. On the other hand, ophthalmologists were required to provide urgent (within 30 days) services to 2% of the cohort, either because of threatening DR or because of incidental findings requiring rapid ophthalmologic attention. Interpretation: This screening strategy for DR through mobile teleophthalmology imaging units efficiently lowered barriers to screening and created new screening opportunities for a large number of known diabetic individuals who were lost to the traditional health system. It has the potential to provide better outreach to diabetic populations while identifying individuals truly in need of the services of an ophthalmologist; at the same time it maximizes the use of limited ophthalmologic resources while favouring multidisciplinary collaborations. The significant incidental findings associated with screening highlight the need for ophthalmologic competencies during DR screening within a teleophthalmology approach. Further involvement of government health authorities is pivotal in embracing the opportunities provided by emerging technologies such as teleophthalmology and translating them into better outreach services to diabetic populations and thus better visual health results.

Population-wide emergence of antiviral resistance during pandemic influenza.

Abstract: Background The emergence of neuraminidase inhibitor resistance has raised concerns about the prudent use of antiviral drugs in response to the next influenza pandemic. While resistant strains may initially emerge with compromised viral fitness, mutations that largely compensate for this impaired fitness can arise. Understanding the extent to which these mutations affect the spread of disease in the population can have important implications for developing pandemic plans.

Why do women have longer durations of unemployment than men in post-restructuring urban China?.

Abstract: This paper provides the first systematic analysis of the reasons why women endure longer unemployment durations than men in post-restructuring urban China. This analysis is based upon data obtained from a national representative household survey. Rejecting the view that women are less earnest than men in their desire for re-employment, this analysis shows that women's job search efforts are handicapped by a lack of access to social networks, unequal entitlement to social re-employment services, higher earnings losses from job separations for women, and unfair treatment of women with respect to mandatory retirement.

Reliability Limits Of The Modified Thomas Test For Assessing Rectus Femoris Muscle Flexibility About The Knee Joint

Abstract: Context: The modified Thomas test is commonly used in the clinical setting to assess flexibility about the thigh region. Objective: To evaluate the clinical reliability of the modified Tho...

Genetic relationships between roost-mates in a fission-fusion society of tree-roosting big brown bats (Eptesicus fuscus)

Abstract: Kin-based patterns of associations are often observed in group living mammals. Colonies of forest- living big brown bats (Eptesicus fuscus) exhibit fission- fusion roosting behavior and female philopatry. Within a roosting area of forest, adult females are distributed into several subgroups roosting in different trees during the day. At night, adult females leave the roost subgroups to forage and, upon return to the roosting area at dawn, both the individual composition and location of subgroups often change. Individuals exhibit nonrandom roosting associa- tions, and we hypothesized that genetic relationships would influence roosting associations. We determined (1) whether the strength of roosting associations between pairs of bats (based on radiotelemetry) was correlated with relatedness, (2) whether individuals that roosted together in roost subgroups were more related than by chance, and (3) from roost subgroups, the pairs of bats that roosted nonrandomly and whether the proportion of related pairs was higher than expected at random. Relatedness measures were based on microsatellite genotyping and mitochondrial DNA sequences. We foundfromall analysesthatroostingassociationswerenot influenced by relatedness or matrilineal relationships. These results provide clear evidence that, contrary to other mam- mals, kinship does not mediate roosting associations within forest living big brown bats that exhibit fission-fusion roosting behavior.

Violence in Young Adolescents' Relationships A Path Model

Abstract: A structural equation model based on social cognitive theory was used to predict relationship violence from young adolescents' knowledge, self-efficacy, attitudes, and alternative conflict strategies (n = 143 male and 147 female grade 7-9 students). A direct causal effect was supported for violence-tolerant attitudes and psychologically aggressive (escalation/blame) strategies on physical violence against dating partners and friends. Knowledge and self-efficacy contributed to using reasoning-based strategies, but this reduced violence only in boys' friendships. Knowledge reduced violence-tolerant attitudes, thus reducing escalation/ blame and physical violence. Attitudes toward male and female dating violence (ATMDV and ATFDV) were indicators of general attitudes toward violence among non-dating students but ATFDV affected physical violence and ATMDV affected psychological aggression for both dating boys and girls.

Periodicity, repetitions, and orbits of an automatic sequence

Abstract: We revisit a technique of S. Lehr on automata and use it to prove old and new results in a simple way. We give a very simple proof of the 1986 theorem of Honkala that it is decidable whether a given k-automatic sequence is ultimately periodic. We prove that it is decidable whether a given k-automatic sequence is overlap-free (or squareefree, or cubefree, etc.) We prove that the lexicographically least sequence in the orbit closure of a k-automatic sequence is k-automatic, and use this last result to show that several related quantities, such as the critical exponent, irrationality measure, and recurrence quotient for Sturmian words with slope alpha, have automatic continued fraction expansions if alpha does.

Morphological constancy in spelling: a comparison of children with dyslexia and typically developing children.

Abstract: The spellings of many English words follow a principle of morphological constancy. For example, musician includes the c of music, even though the pronunciation of this letter changes. With other words, such as explanation and explain, the spellings of morphemes are not retained when affixes are added. We asked whether children with dyslexia use root morphemes to aid their spelling of morphologically complex words. If so, they should sometimes produce misspellings such as ‘explaination’ for explanation. Our results suggest that children with dyslexia adhere to the principle of morphological constancy to the same extent as typically developing younger children of the same spelling level. In this and other ways, the spellings of older dyslexic children are remarkably similar to those of typical younger children. Copyright © 2008 John Wiley & Sons, Ltd.

Effects of technology and male teachers on boys' reading

Abstract: In response to concerns about boys' academic underachievement as well as the international gender imbalance in our teaching force composition, a call has been made to hire more male teachers and practice 'boy-friendly' pedagogy. Our investigation of effects of male reading teachers and use of computer-based books demonstrated their ability to de-feminise boys' views of reading but no differential effects were evident on boys' reading achievement or reader self-perceptions between boys taught by males or by females, whether or not they use technology in their reading practices.