Corporate and Special Collections / Collections générales et spéciales

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Access to healthcare for children with intellectual and developmental disabilities (IDD) in Accra, Ghana : challenges and strategies for improvement
(2017-04) Lamptey, De-Lawrence; School of Rehabilitation Therapy, Queen’s University
Findings of this study reveal that children with intellectual and developmental disabilities (IDD) in Accra are affected by several health conditions, including sensory, respiratory, cardiovascular and gastrointestinal disorders. Results imply that although children with IDD in Ghana might be affected by several health conditions, they confront complex structural and psychosocial barriers in accessing healthcare which undermines Ghana’s commitment on the international front to provide equitable access to healthcare for all. Barriers include financial means, social connections, access to transportation, and attitudes of healthcare providers and the general public toward children with IDD.
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Acute toxicity, accumulation and tissue distribution of copper in the blue crab Callinectes sapidus acclimated to different salinities: in vivo and in vitro studies
(2010) Martins, C M; Barcarolli, I F; de Menezes, E J; Giacomin, M M; Wood, C M
In vivo and in vitro studies were performed to evaluate acute toxicity, organ-specific distribution, and tissue accumulation of copper in Callinectes sapidus acclimated to two different experimental salinities (2 and 30 ppt). Blue crabs were quite tolerant to copper. Acute dissolved copper toxicity (96-h LC50 and its corresponding 95% confident interval) was higher at salinity 2 ppt (5.3 (3.50–8.05) μM Cu) than at 30 ppt (53.0 (27.39–102.52) μM Cu). The difference between salinities can be completely explained based on the water chemistry because it disappeared when 96-h LC50 values were expressed as the free Cu2+ ion (3.1 (1.93–4.95) μM free Cu at 2 ppt versus 5.6 (2.33–13.37) μM free Cu at 30 ppt) or the Cu2+ activity (1.4 (0.88–2.26) μM Cu activity at 2 ppt versus 1.7 (0.71–4.07) μM Cu activity at 30 ppt). The relationships between gill Cu burden and % mortality were very similar at 2 and 30 ppt, in accord with the Biotic Ligand Model. In vivo experiments showed that copper concentration in the hemolymph is not dependent on metal concentration in the surrounding medium at either experimental salinity. They also showed that copper flux into the gills is higher than into other tissues analyzed, and that anterior and posterior gills are similarly important sites of copper accumulation at both experimental salinities. In vitro experiments with isolated-perfused gills showed that there is a positive relationship between copper accumulation in this tissue and the metal concentration in the incubation media for both anterior and posterior gills. A similar result was observed at both low and high salinities. Furthermore, in vitro experiments showed that copper accumulation in posterior gills is also positively and strongly dependent on the incubation time with copper. Gill copper accumulation occurred at a lower rate in the first 2 h of metal exposure, increasing markedly after this “steady-state” period. This finding was corroborated by a significant increase in copper influx to the gill perfusate (corresponding to crab hemolymph) after this time, measured using 64Cu. In vivo, after uptake from solution, 64Cu was primarily accumulated in the gills and the rest of the body rather than in the hemolymph, hepatopancreas, or other internal tissues. Overall, the present findings indicate that gills are a key target organ for copper accumulation, as well as an important biological barrier against the excessive uptake of copper into the hemolymph and the subsequent distribution of this metal to internal organs of the blue crab.
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Amplify-and-Forward Cooperative Diversity for BICM-OFDM Systems
(2010) Islam, T; Schober, R; Mallik, R K; Bhargava, V K
In this paper, we propose a novel amplify-and- forward cooperative diversity scheme for wireless systems using the combination of bit-interleaved coded modulation (BICM) and orthogonal frequency division multiplexing (OFDM). In the proposed scheme, multiple relays transmit concurrently over disjoint sets of sub-carriers. A careful joint design of the sub- carrier allocation at the relays and the interleaver at the source ensures that the proposed scheme can exploit the maximum spatial and frequency diversity offered by the wireless channel. An upper bound on the asymptotic worst-case pairwise error probability of the proposed cooperative diversity scheme is developed which provides insight into to the influence of various code and channel parameters on performance. Simulation results corroborate the analytical results regarding the diversity gain of the system and confirm the effectiveness of a newly developed relay selection criterion.
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Analysis and Design of Cooperative BICM-OFDM Systems
(IEEE, 2011-06) Islam, Toufiqul; Schober, Robert; Mallik, Ranjan K; Bhargava, Vijay K
In this paper, we propose a novel cooperative diversity scheme for wireless systems employing the combination of bit–interleaved coded modulation (BICM) and orthogonal frequency division multiplexing (OFDM). The proposed scheme utilizes an amplify–and–forward protocol where relays are assigned to multiple groups. Relays in the same group transmit concurrently over disjoint sets of sub–carriers and relays in different groups transmit in different time slots. We derive closed–form expressions for the asymptotic worst–case pairwise error probability and the diversity gain of the proposed cooperative BICM–OFDM scheme. Based on the derived analytical results we develop design guidelines for sub–carrier allocation, relay grouping, and relay selection. Simulation results corroborate the derived analytical results and confirm the effectiveness of the developed optimization framework.
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Analysis and relay placement for DF cooperative BICM-OFDM systems
(2011) Islam, T; Nasri, A; Schober, R; Mallik, R K
In this paper, we study a decode-and-forward cooperative diversity scheme for wireless systems using the combination of bit-interleaved coded modulation (BICM) and orthogonal frequency division multiplexing (OFDM). We propose a simple cooperative maximum-ratio combining scheme for the destination which can successfully exploit the full spatial and frequency diversity offered by the channel. Taking possible decision errors at the relay into account, we develop a closed- form upper bound on the asymptotic worst-case pairwise error probability (PEP) of the considered cooperative diversity system which provides insight into the influence of various code and channel parameters on performance. The PEP expression is then exploited for optimal relay placement. Simulation results corroborate the derived analytical results regarding the diversity gain of the system and confirm the effectiveness of the proposed relay placement scheme.
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Asymptotic Performance of Lp-Norm MIMO Detection
(2010) Ahmed, I.; Schober, R; Mallik, R K
Full search L1-norm (FS-L1) and sphere decoding L∞-norm (SD-L∞) detectors have been previously proposed for multiple-input multiple-output (MIMO) systems as they entail a lower receiver complexity than the optimal L2-norm detector. However, the performance loss caused by application of these suboptimal detectors in additive white Gaussian noise (AWGN) has not been well investigated yet. In this paper, we analyze the asymptotic bit error rate of general FS-Lp and SD-Lp detectors in independent identically distributed Rayleigh fading channels. Our results are valid for all types of noise with finite moments including AWGN. We show that both FS-Lp and SD-Lp detectors achieve a diversity gain equal to the number of receive antennas independent of the metric parameter p and the type of noise. However, except for the conventional L2 case, the performances of FS-Lp and SD-Lp detectors are not identical and the performance differences may be several dB for large numbers of receive antennas. Also, our results show that p=2 is not optimal in non-Gaussian noise and L1 and L∞ detectors may result in large performance gains or degradations compared to L2 detectors depending on the type of noise.
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Biomarkers response to zinc exposure in the symbiont-bearing foraminifer Amphistegina lessonii (Amphisteginidae, Foraminifera)
(2011) Prazeres, M F; Martins, S E; Bianchini, A
The aim of the study is to evaluate populations of the symbiont-bearing foraminifer Amphistegina lessonii both by using established visual assessment methods and by adapting cellular diagnostic methods for use on these protists. Findings suggest that an activation of some components of the antioxidant system occurred in A. lessonii to counteract the oxidative stress induced by Zn exposure, and consequently avoid a possible complete loss of the symbiont.See also http://hdl.handle.net/10625/49042
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Chitobiase of planktonic crustaceans from South Atlantic coast (Southern Brazil): Characterization and influence of abiotic parameters on enzyme activity
(2011) Avila, T R; Machado, A A S; Bianchini, A
Chitobiase is one of the enzymes involved in chitin degradation in nature. It is produced and released by a variety of organisms from bacteria to fish. In crustaceans, it is associated with digestive function and acts on the epidermis during the molting process. In the present study, the influence of water pH, temperature and salinity on maximum chitobiase activity (MCA), as well as the enzyme affinity (Km) for a substrate, the methylumbelliferyl N-acetyl-ß-d-glucosaminide (MUFNAG) was evaluated in the copepod Acartia tonsa. Km values for chitobiases of other crustaceans from the Patos Lagoon estuary and Cassino Beach (Southern Brazil) were also determined. For A. tonsa, MCA was observed at pH 5–6 and 30–35 °C. The range of pH was quite similar to that reported for other aquatic organisms. However, the range of temperature was lower than that previously reported. For salinity, no previous studies have considered the influence of this parameter on MCA. For A. tonsa, MCA was observed in freshwater, showing a significant linear decrease with increasing salinity. Considering that maximum copepod survival and growth rates are observed between 15 and 25 ppt, these findings suggest that the observed enzyme activity in this range of salinity (68 to 47% of that measured in freshwater) is not a limiting factor for A. tonsa growth. However, the extremely decreased enzyme activity observed in salinity 30 ppt (33% of that measured in freshwater) suggests that chitobiase activity might be one of the limiting factor for copepod growth at 30 ppt salinity or higher. Km values (μM) determined for organisms evaluated in the present study (copepod A. tonsa = 20.77; mysid Metamysidopsis elongata atlantica = 14.67; nauplii barnacle Balanus improvisus = 18.19; decapod zoea = 14.30; decapod megalopa = 24.77) were lower than those reported for other crustaceans from Northern Hemisphere. Also, they were much lower than those of organisms from different taxonomic groups like bacteria and fungi, but much higher than in protozoans and dinoflagelates. These findings suggest that chitobiase might be differentially evolved in each specific group of organism, and even within different ontogenetic stages of the same species, for a better adaptation to cope with its respective environmental needs.
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Climate for evidence-informed health systems: a profile of systematic review production in 41 low- and middle-income countries, 1996–2008
(2011) Law, Tyler; Lavis, John; Hamandi, Ali; Cheung, Andrew; El-Jardali, Fadi
Objective: To describe systematic review production in 41 countries in Africa, the Americas, Asia and the eastern Mediterranean to understand one dimension of the climate for evidence-informed health systems and to provide a baseline for an evaluation of knowledge translation initiatives.Methods: Our focus was systematic reviews published between 1996 and 2008 that had a corresponding author based in, or that appeared to target, one of the countries in these regions. We searched both Medline and Embase using validated search strategies, identified citations with a country name in the corresponding author's institutional affiliation or as a textword (i.e., an explicit mention in the title or abstract) or keyword, and coded articles describing a systematic review. We followed the same citation identification procedure for Health Systems Evidence, a database containing systematic reviews about health systems. Results: Systematic review production increased between three-fold (for Africa in Medline) and 110-fold (for Asia in Embase) between the first period (1996–2002) and second period (2003–2008). In the second period, China was more often the home of corresponding authors and the target of reviews than any other country. No systematic reviews were produced by a corresponding author based in nine countries, or appeared to target five countries. Only 48 reviews identified through Medline and Embase addressed health systems, and 35 health systems reviews identified through Health Systems Evidence addressed these countries. Conclusion: In many countries, those seeking to support evidence-informed health systems cannot turn to experienced local systematic reviewers to help them to find and use systematic reviews or to conduct reviews on high priority topics when none exists. These findings suggest the need for local capacity-building initiatives.
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Compensation for environmental services from artisanal fisheries in SE Brazil: Policy and technical strategies
(Elsevier, Netherlands, 2011-09) Begossi, Alpina; May, Peter H; Lopes, Priscila F; Oliveira, Luiz E C; da Vinha, Valéria
Artisanal fisheries are of great importance in Brazil, as they are responsible for more than 50% of national fish production. This importance, associated with the necessity of conserving marine environments threatened by multiple competing uses, leads us to propose mechanisms for co-management of fisheries by users and public authorities. This proposal takes into account: a) local conflicts between artisanal and industrial fishers; b) local rules over the use of fishing areas established by artisanal fishers; c) the advent of protected areas that close access to some fishing areas used by artisanal fisheries; and d) co-management options being explored between government and fishers. This study suggests policy and technical alternatives under consideration to manage the artisanal fisheries of southeastern Brazil with a focus on Ilha Grande bay in Rio de Janeiro. In our case study, based on field research conducted in 2009, we show that artisanal fishers are squeezed into a marine space between protected areas and industrial fishing. We suggest that a combination of fishing agreements (FAs), based on experience in Amazonian fisheries and extractive reserves, and payment for environmental services (PES), based on forest and related water resource experience, could improve management and livelihoods for local artisanal fisheries by stimulating and rewarding fishers who participate in conservation efforts. The two instruments (FAs and PES) are the subject of considerable research and practical experience. Their integration in an instrument mix represents a contribution from transdisciplinary fields of human ecology and ecological economics.
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Cooperative BICM-OFDM: Sub-carrier and power allocation
(2010) Islam, T; Schober, R; Mallik, R K; Bhargava, V K
In this paper, we consider amplify-and-forward cooperative diversity for wireless systems employing bit-interleaved coded modulation (BICM) and orthogonal frequency division multiplexing (OFDM). In the second hop, multiple relays transmit concurrently over disjoint sets of sub-carriers. We propose uniform and non-uniform sub-carrier allocation schemes, which guarantee full diversity if all involved channels have identical lengths. The non-uniform allocation scheme also guarantees full diversity if the involved channels have different lengths. In addition, we formulate a power allocation problem for minimization of an upper bound on the worst-case pairwise error probability of the considered cooperative diversity scheme and provide an efficient solution using geometric programming. Simulation results confirm the effectiveness of the proposed sub- carrier and power allocation schemes.
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Dietary salt supplementation for juvenile mullet Mugil platanus reared in freshwater
(2011) Lisboa da Cunha, Viviana; Barcarolli, Indianara Fernanda; Sampaio, Luis André; Bianchini, Adalto
Dietary salt supplementation for seawater/euryhaline fish reared in low salinities and/or freshwater might spare energy expenditure for osmoregulation allowing more energy for growth. Growth of mullet Mugil platanus is hampered in hypoosmotic environments, thus the objective of this study was to evaluated the effect of dietary salt supplementation on their performance when reared in freshwater. Two hundred and forty fish (4.50 ± 0.07g e 7.41 ± 0.03cm) were randomly distributed into 16 tanks (50L). These tanks were connected to a recirculating aquaculture system (RAS) equipped with UV sterilization, mechanical and biological filtration and temperature controller. A commercial diet (32%CP and 1.5% NaCl) was grinded to powder, supplemental salt was added, and cellulose was used to compensate for the extra salt. Fish were fed 3 times per day on diets supplemented with 0, 3, 6, and 9% NaCl. During the experiment, fish were maintained at temperature of 27 ± 0.1°C, oxygen saturation above 89%, 78.56 ± 1.09, 7.92 ± 0.02 and photoperiod 14C:10E. Fish were fed three times per day until apparent satiation. Biometry was made every 15 days. The data (average ± SE) were analyzed by analysis of variance (One-Way) (ANOVA) followed by Test of Tukey. All analyses were performed with significance level of p<0.05 and were conducted using the software statistic 6.0. Dietary salt supplementation did not affect survival of juvenile mullet, survival was above 90% in all tanks. Feed efficiency was not influenced by the experimental diets either, it averaged 0.31 ± 0.01 (p>0.05). However, final weight of juvenile mullet fed NaCl-enriched diets (6 and 9%) was significantly smaller than fish fed control or NaCl-enriched (3%) diets (p<0.05) (Figure 1). Considering the specific growth rate, juvenile mullet fed NaCl-enriched diet (9%) showed the poorest performance when compared to fish fed any other diet (Figure 2). Results indicated that diets supplemented with NaCl are not beneficial to juvenile mullet. Furthermore, excess salt (6% and 9% NaCl) are harmfull and compromise their growth
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Dynamics of an interactional model of rabies transmitted between human and dogs
(2009) Yang, Wei; Lou, Jie
Assuming that the population of dogs is constant and the population of human satisfies the Logistical model, an interactional model of rabies transmitted between human and dogs is formulated. Two thresholds R0 and R1 which determine the outcome of the disease are identified. Utilizing the method of Lyapunov function and the property of the cooperative systems, we get the global asymptotic stability for bath the disease-free equilibrium and the endemic equilibrium. A critical vaccination rate is obtained, which determines whether the dog rabies dies out or becomes endemic. Some suggestions are provided to the prevention and control of rabies according to the results of analysis and simulations.
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Dynamics of spreading and immune strategies of sexually transmitted diseases on scale-free network
(2009) Lou, Jie; Ruggen, Tommaso
We examine epidemic threshold and dynamics for sexually transmitted diseases (STDs) spread using a multiple susceptible-infected–removed-susceptible ODE model on scale-free networks. We derive the threshold for the epidemic to be zero in infinite scale-free network. For a hard cut off scale-free network, we also prove the stability of disease-free equilibrium and the persistence of STDs infection. The effects of two immunization schemes, including proportional scheme and targeted vaccination, are studied and compared. We find that targeted strategy compare favorably to a proportional scheme in terms of effectiveness. Theory and simulations both prove that an appropriate condom using has prominent effect to control STDs spread on scale-free networks.
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Effect of copper on ion content in isolated mantle cells of the marine clam Mesodesma mactroides
(2011) Lopes, T M; Barcarolli, I F; de Oliveira, C B; Souza, M M
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Effects of population dispersal and pulse vaccination on disease control
(2010) Yang, Youping; Xiao, Yanni
In this paper, we investigate a nonautonomous SIR type epidemic model with pulse vaccination in patchy environments. We obtain a threshold parameter which governs the extinction or the uniform persistence of the disease by applying Floquet theory and the comparison theorem of impulsive differential equations. Numerical results indicate that population dispersal has significant effects on disease transmission. Varying the population dispersal rates between two patches in which the disease would die out if they had remained isolated, could allow the disease to persist globally. Alternatively, similar variations between patches where the disease would be persistent if isolated can lead to extinction globally. Finally, the model was generalized and we extended the definition of the basic reproduction number in a continuous (autonomous or periodic) system to that for a hybrid system as the spectral radius of the next infection operator.
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Effects of salinity on acute and chronic nickel toxicity and bioaccumulation in two euryhaline crustaceans: Litopenaeus vannamei and Excirolana armata
(2011) Leonard, E M; Barcarolli, I; Silva, K R; Wasielesky, W; Wood, C M
We investigated the influence of salinity (5 ppt versus 25 ppt) on acute (96-h LC50) and chronic toxicity (15–30 day LC50) of Ni in two euryhaline crustaceans, the shrimp (Litopenaeus vannamei) and the isopod (Excirolana armata). 96-h LC50 values were 41 μmol L−1 and 362 μmol L−1 for L. vannamei and 278 μmol L−1 and > 1000 μmol L−1 for E. armata at 5 ppt and 25 ppt, respectively. Speciation analysis demonstrated that complexation with anions such as SO42−, HCO3− and Cl− at 25 ppt had a negligible effect on reducing the free Ni2+ ion component in comparison to 5 ppt. The salinity-dependent differences in acute Ni toxicity could not be explained by differences in Ni bioaccumulation. Therefore, differences in physiology of the organisms at the two salinities may be the most likely factor contributing to differences in acute Ni toxicity. Chronic LC50 values (2.7–23.2 μmol L−1) were similar in the two species, but salinity had no significant effect, indicating that water chemistry and osmoregulatory strategy do not influence chronic toxicity. However chronic (15-day) mortality in both species could be predicted by acute (96-h) Ni bioaccumulation patterns.
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Effects of salinity on growth of juvenile mullet Mugil platanus
(2011) Lisboa da Cunha, Viviana; Barcarolli, Indianara Fernanda; Sampaio, Luis André; Bianchini, Adalto
Assuming the energetic cost of osmoregulation is minimized in an isosmotic medium, the energy spared could support a higher growth rate of fish. The isosmotic point of juvenile mullet Mugil platanus was estimated at 414 mOsmol/Kg H2O, which corresponds to salinity 12‰.The aim of this study was to investigate the effect of salinity on the performance of juvenile mullet reared at different salinities. Four hundred and eighty fish (0.48±0.01g and 3.27±0.01cm) were randomly distributed into 16 tanks (50L). These tanks were connected to four recirculating aquaculture systems (RAS) equipped with UV sterilization, mechanical and biological filtration and temperature controllers. Each RAS was maintained at salinities 0, 6, 12, and 24, equivalent to 0, 50, 100 and 200% of the isosmotic point of M. platanus. During the experimental period (40 days), fish were maintained at 28.2 ± 0.1°C and oxygen saturation was always above 90%. Fish were fed 4 times per day on NRD INVE (50% protein) until apparent satiation. Results were analyzed by analysis of variance (One-Way) followed by Test of Tukey. All analyses were performed with significance level of p<0.05 and were conducted using the software Statistic 6.0. Salinity did not influence survival of juvenile mullet (p>0.05), nor influenced feed efficiency. However, final weight and specific growth rate were significantly affected at different salinities (p<0.05). Overall survival was above 90% and feed efficiency was y. Fish reared at salinities 12 and 24 grew faster than those reared at lower salinities (Figure 1 and 2) Results indicated that salinity plays an important role in juvenile mullet growth and that final weight and SGR were maximized when they were reared at salinity equivalent to, or higher, than the isosmotic point.
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Estimating Feature Ratings through an Effective Review Selection Approach
(2012) Long, C; Zhang, J; Huang, M; Li, M; Ma, B
Most participatory websites collect overall ratings (e.g. five stars) of products from their customers, reflecting the overall assessment of the products. However, it is more useful to present ratings of product features (such as price, battery, screen and lens of digital cameras) to help customers make effective purchase decisions. Unfortunately,only a very few websites have collected feature ratings. In this paper, we propose a novel approach to accurately estimate feature ratings of products. In this paper, we propose a novel approach to accurately estimate feature ratings of products. This approach selects user reviews that extensively discuss specific features of the products (called specialized reviews), using information distance of reviews on the features. Experiments on both annotated and real data show that overall ratings of the specialized reviews can be used to represent their feature ratings. The average of these overall ratings can be used by recommender systems to provide feature-specific recommendations that can better help users make purchasing decisions.
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Estudo de método para extração de agrotóxicos em hepatopâncreas de siri por MSPD e determinação por CG-IE-EM
(2011) Bolzan, C M; Martins, G A; de Menezes, E J; Caldas, S S; Dias, A N
A ocorrência de inúmeros compostos orgânicos nos compartimentos bióticos e os possíveis efeitos deletérios que estes podem causar aos ecossistemas aquáticos tem sido uma crescente preocupação. Embora a determinação destes compostos gere informações suplementares com relação aos contaminantes biodisponíveis, as determinações de resíduos de agrotóxicos em espécies comuns do ambiente aquático são geralmente desconhecidas. Em tecidos biológicos, onde as concentrações do analito são baixas e a matriz é complexa, o preparo de amostra é uma etapa fundamental. A técnica de dispersão da matrix em fase sólida (MSPD), apresenta as vantagens de utilizar pequena quantidade de amostra e baixo volume de solventes orgânicos, além de baixo custo e rapidez. O objetivo deste trabalho foi otimizar um método empregando extração por MSPD e determinação por cromatografia gasosa acoplada a espectrometria de massas (CG-EM) de 7 agrotóxicos em amostras de hepatopâncreas de siri.

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