253 research outputs found

    Effects of replacing marine fishmeal with graded levels of Tra Catfish by-product protein hydrolysate on the performance and meat quality of pigs

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    A feeding trial was carried out to evaluate the effects of replacing fish meal (FM) with Tra Catfish (Pangasius hypophthalmus) by-product protein hydrolysate (TPH) on performance and carcass quality in pigs. Forty crossbred castrated (Yorkshire x Landrace) male pigs with an initial average bodyweight of 22.8 ± 1.5 kg were allocated to 40 individual pens in a randomized complete block design with eight replications. The pigs were fed a control diet (TPH0) with FM as sole protein supplement. In the experimental diets, 100% (TPH100), 75% (TPH75), 50% (TPH50) and 25% (TPH25) of the crude protein (CP) from FM was replaced by the CP from TPH. The results showed no significant differences in average daily feed intake (ADFI) in all treatments during the growing and finishing phases. However, daily weight gain (ADG) was higher in TPH75 (655 g/day) and TPH100 (663 g/day) than in TPH0 (639 g/day). Feed conversion ratio (FCR) was improved with higher inclusion of TPH in the diets. Carcass yield and dressing percentage were not affected by treatments, but abdominal fat and backfat thickness were higher and in the loin-eye area lower in TPH100 compared with TPH0. Polyunsaturated fatty acids (PUFA), ether extract (EE) contents and meat colour values a* (redness) in the longissimus dorsi muscle increased with TPH replacement level. Feed costs were 10% lower in TPH100 compared with TPH0. In conclusion, replacing FM with TPH improved the performance, but resulted in an increase in backfat thickness and fat content of meat. However, because of reduced feed costs, complete replacement of FM would still be profitable for pig producers in Vietnam.Keywords: Backfat thickness, longissimus dorsi muscle, fatty acid, Pangasius hypophthalmu

    Cobweb Heuristic for solving Multi-Objective Vehicle Routing Problem

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    Abstract Solving a classical vehicle routing problem (VRP) by exact methods presents many difficulties for large dimension problem. Consequently, in multi-objective framework, heuristic or metaheuristic methods are required. Due to particular VRP structure, it seems that a dedicated heuristic is more suitable than a metaheuristic. The aim of this article is to collapse different heuristics solving classical VRP and adapt them for to solve the multi-objective vehicle routing problem (MOVRP). The so-called Cobweb Algorithm simulates spider’s behavior when weaving cobweb. This paper presents the algorithm, a didactic example, concluding remarks and way for further researches

    Cobweb Heuristic for solving Multi-Objective Vehicle Routing Problem

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    Abstract Solving a classical vehicle routing problem (VRP) by exact methods presents many difficulties for large dimension problem. Consequently, in multi-objective framework, heuristic or metaheuristic methods are required. Due to particular VRP structure, it seems that a dedicated heuristic is more suitable than a metaheuristic. The aim of this article is to collapse different heuristics solving classical VRP and adapt them for to solve the multi-objective vehicle routing problem (MOVRP). The so-called Cobweb Algorithm simulates spider’s behavior when weaving cobweb. This paper presents the algorithm, a didactic example, concluding remarks and way for further researches

    Adaptation de l’heuristique de Clarke & Wright au contexte multi-objectif grâce a la méthode du repère préférentiel de dominance

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    Résumé : L’heuristique des économies de Clarke et Wright est le modèle de référence pour la résolution du problème classique de tournées de véhicules. Dans cet article, après l’énoncé de ce dernier problème en présence des objectifs multiples, nous ajustons judicieusement les paramètres du modèle initial dans ce nouveau contexte pour une version multi-objectif grâce à la méthode du repère préférentiel de dominance. Un exemple didactique valide cette démarche. Le principal résultat est l’obtention de tout l’ensemble des solutions efficaces E(P) mais de manière échelonnée Abstract : Economics’ heuristic of Clarke and Wright is the principle and benchmark model for solving vehicle routing problem. In this article, after presentation of the problem, we adjust initial model parameters in this new context for a multiobjeciive version. The principal result is the E(P) obtaining in his globally but in a sequential way. A didactic example is presented to illustrate the method

    Adaptation de l’heuristique de Clarke & Wright au contexte multi-objectif grâce a la méthode du repère préférentiel de dominance

    Get PDF
    Résumé : L’heuristique des économies de Clarke et Wright est le modèle de référence pour la résolution du problème classique de tournées de véhicules. Dans cet article, après l’énoncé de ce dernier problème en présence des objectifs multiples, nous ajustons judicieusement les paramètres du modèle initial dans ce nouveau contexte pour une version multi-objectif grâce à la méthode du repère préférentiel de dominance. Un exemple didactique valide cette démarche. Le principal résultat est l’obtention de tout l’ensemble des solutions efficaces E(P) mais de manière échelonnée Abstract : Economics’ heuristic of Clarke and Wright is the principle and benchmark model for solving vehicle routing problem. In this article, after presentation of the problem, we adjust initial model parameters in this new context for a multiobjeciive version. The principal result is the E(P) obtaining in his globally but in a sequential way. A didactic example is presented to illustrate the method

    Efficacy of personalized cognitive counseling in men of color who have sex with men: secondary data analysis from a controlled intervention trial.

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    In a previous report, we demonstrated the efficacy of a cognitively based counseling intervention compared to standard counseling at reducing episodes of unprotected anal intercourse (UAI) among men who have sex with men (MSM) seeking HIV testing. Given the limited number of efficacious prevention interventions for MSM of color (MOC) available, we analyzed the data stratified into MOC and whites. The sample included 196 white MSM and 109 MOC (23 African Americans, 36 Latinos, 22 Asians, eight Alaskan Natives/Native Americans/Hawaiian/Pacific Islander, and 20 of mixed or other unspecified race). Among MOC in the intervention group, the mean number of episodes of UAI declined from 5.1 to 1.6 at six months and was stable at 12 months (1.8). Among the MOC receiving standard counseling, the mean number of UAI episodes was 4.2 at baseline, 3.9 at six months and 2.1 at 12 months. There was a significant treatment effect overall (relative risk 0.59, 95% confidence interval 0.35-0.998). These results suggest that the intervention is effective in MOC

    Perinatal outcomes in a South Asian setting with high rates of low birth weight

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    <p>Abstract</p> <p>Background</p> <p>It is unclear whether the high rates of low birth weight in South Asia are due to poor fetal growth or short pregnancy duration. Also, it is not known whether the traditional focus on preventing low birth weight has been successful. We addressed these and related issues by studying births in Kaniyambadi, South India, with births from Nova Scotia, Canada serving as a reference.</p> <p>Methods</p> <p>Population-based data for 1986 to 2005 were obtained from the birth database of the Community Health and Development program in Kaniyambadi and from the Nova Scotia Atlee Perinatal Database. Menstrual dates were used to obtain comparable information on gestational age. Small-for-gestational age (SGA) live births were identified using both a recent Canadian and an older Indian fetal growth standard.</p> <p>Results</p> <p>The low birth weight and preterm birth rates were 17.0% versus 5.5% and 12.3% versus 6.9% in Kaniyambadi and Nova Scotia, respectively. SGA rates were 46.9% in Kaniyambadi and 7.5% in Nova Scotia when the Canadian fetal growth standard was used to define SGA and 6.7% in Kaniyambadi and < 1% in Nova Scotia when the Indian standard was used. In Kaniyambadi, low birth weight, preterm birth and perinatal mortality rates did not decrease between 1990 and 2005. SGA rates in Kaniyambadi declined significantly when SGA was based on the Indian standard but not when it was based on the Canadian standard. Maternal mortality rates fell by 85% (95% confidence interval 57% to 95%) in Kaniyambadi between 1986–90 and 2001–05. Perinatal mortality rates were 11.7 and 2.6 per 1,000 total births and cesarean delivery rates were 6.0% and 20.9% among live births ≥ 2,500 g in Kaniyambadi and Nova Scotia, respectively.</p> <p>Conclusion</p> <p>High rates of fetal growth restriction and relatively high rates of preterm birth are responsible for the high rates of low birth weight in South Asia. Increased emphasis is required on health services that address the morbidity and mortality in all birth weight categories.</p

    Imagable 4T1 model for the study of late stage breast cancer

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    <p>Abstract</p> <p>Background</p> <p>The 4T1 mouse mammary tumor cell line is one of only a few breast cancer models with the capacity to metastasize efficiently to sites affected in human breast cancer. Here we describe two 4T1 cell lines modified to facilitate analysis of tumor growth and metastasis and evaluation of gene function <it>in vivo</it>. New information regarding the involvement of innate and acquired immunity in metastasis and other characteristics of the model relevant to its use in the study of late stage breast cancer are reported.</p> <p>Methods</p> <p>The lines were engineered for stable expression of firefly luciferase to allow tracking and quantitation of the cells <it>in vivo</it>. Biophotonic imaging was used to characterize growth and metastasis of the lines <it>in vivo </it>and an improved gene expression approach was used to characterize the basis for the metastatic phenotype that was observed.</p> <p>Results</p> <p>Growth of cells at the primary site was biphasic with metastasis detected during the second growth phase 5–6 weeks after introduction of the cells. Regression of growth, which occurred in weeks 3–4, was associated with extensive necrosis and infiltration of leukocytes. Biphasic tumor growth did not occur in BALB/c SCID mice indicating involvement of an acquired immune response in the effect. Hematopoiesis in spleen and liver and elevated levels of circulating leukocytes were observed at week 2 and increased progressively until death at week 6–8. Gene expression analysis revealed an association of several secreted factors including colony stimulatory factors, cytokines and chemokines, acute phase proteins, angiogenesis factors and ECM modifying proteins with the 4T1 metastatic phenotype. Signaling pathways likely to be responsible for production of these factors were also identified.</p> <p>Conclusion</p> <p>The production of factors that stimulate angiogenesis and ECM modification and induce hematopoiesis, recruitment and activation of leukocytes suggest that 4T1 tumor cells play a more direct role than previously appreciated in orchestrating changes in the tumor environment conducive to tumor cell dissemination and metastasis. The new cell lines will greatly facilitate the study of late stage breast and preclinical assessment of cancer drugs and other therapeutics particularly those targeting immune system effects on tumor metastasis.</p

    Influence of Microbial Biofilms on the Preservation of Primary Soft Tissue in Fossil and Extant Archosaurs

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    Background: Mineralized and permineralized bone is the most common form of fossilization in the vertebrate record. Preservation of gross soft tissues is extremely rare, but recent studies have suggested that primary soft tissues and biomolecules are more commonly preserved within preserved bones than had been presumed. Some of these claims have been challenged, with presentation of evidence suggesting that some of the structures are microbial artifacts, not primary soft tissues. The identification of biomolecules in fossil vertebrate extracts from a specimen of Brachylophosaurus canadensis has shown the interpretation of preserved organic remains as microbial biofilm to be highly unlikely. These discussions also propose a variety of potential mechanisms that would permit the preservation of soft-tissues in vertebrate fossils over geologic time. Methodology/Principal Findings: This study experimentally examines the role of microbial biofilms in soft-tissue preservation in vertebrate fossils by quantitatively establishing the growth and morphology of biofilms on extant archosaur bone. These results are microscopically and morphologically compared with soft-tissue extracts from vertebrate fossils from the Hell Creek Formation of southeastern Montana (Latest Maastrichtian) in order to investigate the potential role of microbial biofilms on the preservation of fossil bone and bound organic matter in a variety of taphonomic settings. Base

    Investigating the global genomic diversity of Escherichia coli using a multi-genome DNA microarray platform with novel gene prediction strategies

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    <p>Abstract</p> <p>Background</p> <p>The gene content of a diverse group of 183 unique <it>Escherichia coli </it>and <it>Shigella </it>isolates was determined using the Affymetrix GeneChip<sup>® </sup><it>E. coli </it>Genome 2.0 Array, originally designed for transcriptome analysis, as a genotyping tool. The probe set design utilized by this array provided the opportunity to determine the gene content of each strain very accurately and reliably. This array constitutes 10,112 independent genes representing four individual <it>E. coli </it>genomes, therefore providing the ability to survey genes of several different pathogen types. The entire ECOR collection, 80 EHEC-like isolates, and a diverse set of isolates from our FDA strain repository were included in our analysis.</p> <p>Results</p> <p>From this study we were able to define sets of genes that correspond to, and therefore define, the EHEC pathogen type. Furthermore, our sampling of 63 unique strains of O157:H7 showed the ability of this array to discriminate between closely related strains. We found that individual strains of O157:H7 differed, on average, by 197 probe sets. Finally, we describe an analysis method that utilizes the power of the probe sets to determine accurately the presence/absence of each gene represented on this array.</p> <p>Conclusions</p> <p>These elements provide insights into understanding the microbial diversity that exists within extant <it>E. coli </it>populations. Moreover, these data demonstrate that this novel microarray-based analysis is a powerful tool in the field of molecular epidemiology and the newly emerging field of microbial forensics.</p
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