228 research outputs found

    A Hierarchical Recurrent Encoder-Decoder For Generative Context-Aware Query Suggestion

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    Users may strive to formulate an adequate textual query for their information need. Search engines assist the users by presenting query suggestions. To preserve the original search intent, suggestions should be context-aware and account for the previous queries issued by the user. Achieving context awareness is challenging due to data sparsity. We present a probabilistic suggestion model that is able to account for sequences of previous queries of arbitrary lengths. Our novel hierarchical recurrent encoder-decoder architecture allows the model to be sensitive to the order of queries in the context while avoiding data sparsity. Additionally, our model can suggest for rare, or long-tail, queries. The produced suggestions are synthetic and are sampled one word at a time, using computationally cheap decoding techniques. This is in contrast to current synthetic suggestion models relying upon machine learning pipelines and hand-engineered feature sets. Results show that it outperforms existing context-aware approaches in a next query prediction setting. In addition to query suggestion, our model is general enough to be used in a variety of other applications.Comment: To appear in Conference of Information Knowledge and Management (CIKM) 201

    Network coding cooperation performance analysis in wireless network over a lossy channel, M users and a destination scenario

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    Network coding (NC), introduced at the turn of the century, enables nodes in a network to combine data algebraically before either sending or forwarding them. Random network coding has gained popularity over the years by combining the received packet randomly before forwarding them, resulting in a complex Jordan Gaussian Elimination (JGE) decoding process. The effectiveness of random NC is through cooperation among nodes. In this paper, we propose a simple, low-complexity cooperative protocol that exploits NC in a deterministic manner resulting in improved diversity, data rate, and less complex JGE decoding process. The proposed system is applied over a lossy wireless network. The scenario under investigation is as follows: M users must send their information to a common destination D and to exchange the information between each others, over erasure channels; typically the channels between the users and the destination are worse than the channels between users. It is possible to significantly reduce the traffic amon g users and destination, achieving significant bandwidth savings, by combining packets from different users in simple, deterministic ways without resorting to extensive header information before being forwarded to the destination and the M users. The key problem we try to address is how to efficiently combine the packets at each user while exploiting user cooperation and the probability of successfully recovering information from all users at D with k < 2M unique linear equations, accounting for the fact that the remaining packets will be lost in the network and there are two transmission stages. Simulation results show the behaviour for two and three transmission stages. Our results show that applying NC protocols in two or three stages decreases the traffic significantly, beside the fact that the proposed protocols enable the system to retrieve the lost packets rather than asking for ARQ, resulting in improved data flow, and less power consumption. In fact, in some protocols the ARQ dropped from the rate 10-1 to 10-4, because of the proposed combining algorithm that enables the nodes to generate additional unique linear equations to broadcast rather than repeating the same ones via ARQ. Moreover, the number of the transmitted packets in each cooperative stage dropped from M (M − 1) to just M packets, resulting to 2 M packets instead 2 (M2 −  1) when three stages of transmission system are used instead of one stage (two cooperative stages)

    Arab immigrants in the Canadian labour market : expectations and compromises

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    Immigrants have always played an important role in the development of Canada. This study analyzes the adjustment problems of Arab immigrants who live in Montreal and have immigrated to Canada in the 1980's and the 1990's. It is an attempt to explore the nature of their economic adaptation. Economic adaptation is raised here as one aspect--albeit an important one--of their integration in the larger society. I have used both quantitative and qualitative methods in the analysis of the data that I have obtained from the interviews of the sample of Arab immigrants. The findings indicate that Canadian education and experience, length of residence, official languages proficiency (especially French), marital status and community support are major influences in their integration in the Montreal labour market. This thesis also examines the relationships among expectations, compromises and outcomes

    Views of Diagnostic Radiology Residency Program Directors Regarding Methods to Increase Female and Under-Represented in Medicine Residents: A Cross-sectional Study

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    RATIONALE AND OBJECTIVES: Diagnostic radiology remains one of the least diverse medical specialties. Recent reports have found that the number of female and under-represented in medicine (URiM) residents have not increased despite efforts to increase representation over the last decade. Given the critical role of residency program directors in selecting diverse applicants, this study was performed to identify which strategies were most preferred to increase the number of female and/or URiM residents by directors of diagnostic radiology residency training programs. MATERIALS AND METHODS: This was an anonymous, cross-sectional study of diagnostic radiology residency program directors that included a survey about program characteristics, demographics, and strategies to increase the number of female and/or URiM residents. RESULTS: The questionnaire was submitted to 181 potential participants with a 19.9% response rate. The most preferred strategies to increase diversity involved directly recruiting medical students, promoting mentorship, increasing the number of diverse teaching faculty, and unconscious bias training. The least supported strategies included deemphasizing exam scores, accepting more international graduates, accepting a minimum number of female and/or URiM applicants, and de-identifying applications. Female and/or URiM program directors indicated a statistically significant preference for medical student recruitment and providing an opportunity to discuss workplace issues for female and/or URiM trainees (p \u3c 0.05). CONCLUSION: Diagnostic radiology residency program directors endorsed a wide variety of strategies to increase diversity. Recruitment of female and/or URiM medical students and promoting the number of diverse faculty members and mentorship of trainees by these faculty appear to be the most preferred strategies to increase female and/or URiM residents. Female and/or URiM program directors placed a greater importance on recruiting diverse applicants and supporting safe discussion of workplace issues faced by female and/or URiM radiology residents

    Diet Enriched with Olive Oil Attenuates Placental Dysfunction in Rats with Gestational Diabetes Induced by Intrauterine Programming

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    Scope: Offspring from rats with mild diabetes develop gestational diabetes mellitus (GDM). We tested the hypothesis that an olive oil-supplemented diet attenuates placental oxidative stress/inflammation, activation of mTOR signaling, and inhibition of peroxisome proliferator-activated receptor γ (PPARγ) and fetal overgrowth in GDM offspring from mild diabetic rats. Methods and results: Female offspring from rats with mild diabetes (group that developed GDM) and controls were fed with either a standard diet or a 6% olive oil-supplemented diet during pregnancy. On day 21 of pregnancy, plasma glucose levels in mothers and fetuses were increased in the GDM group independently of the diet. Fetal overgrowth and activation of placental mTOR signaling were partially prevented in the olive oil-treated GDM group. Placental PPARγ protein expression was decreased in GDM rats, independently of the diet. However, increases in placental lipoperoxidation, connective tissue growth factor, and matrix metalloproteinase 2 levels were prevented by the olive oil-enriched diet. Conclusion: Diets enriched with olive oil attenuate placental dysfunction and fetal overgrowth in rats with GDM induced by intrauterine programming.Fil: Capobianco, Evangelina Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Gomez Ribot, Dalmiro Leonardo Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Fornes, Daiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Powell, Theresa L.. Universidad de Colorado, Denver; Estados UnidosFil: Levieux, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; ArgentinaFil: Jansson, Thomas. State University of Colorado at Boulder; Estados UnidosFil: Jawerbaum, Alicia Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; Argentin

    Three peroxisome proliferator-activated receptor isotypes from each of two species of marine fish

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    The cloning and characterization of cDNAs and genes encoding three peroxisome proliferator-activated receptor (PPAR) isotypes from two species of marine fish, the plaice (Pleuronectes platessa) and the gilthead sea bream (Sparus aurata), are reported for the first time. Although differences in the genomic organization of the fish PPAR genes compared with their mammalian counterparts are evident, sequence alignments and phylogenetic comparisons show the fish genes to be homologs of mammalian PPAR&alpha;, PPAR&beta;/&delta;, and PPAR&gamma;. Like their mammalian homologs, fish PPARs bind to a variety of natural PPAR response elements (PPREs) present in the promoters of mammalian or piscine genes. In contrast, the mRNA expression pattern of PPARs in the two fish species differs from that observed in other vertebrates. Thus, PPAR&gamma; is expressed more widely in fish tissues than in mammals, whereas PPAR&alpha; and &beta; are expressed similarly in profile to mammals. Furthermore, nutritional status strongly influences the expression of all three PPAR isotypes in liver, whereas it has no effect on PPAR expression in intestinal and adipose tissues. Fish PPAR&alpha; and &beta; exhibit an activation profile similar to that of the mammalian PPAR in response to a variety of activators/ligands, whereas PPAR&gamma; is not activated by mammalian PPAR&gamma;-specific ligands. Amino acid residues shown to be critical for ligand binding in mammalian PPARs are not conserved in fish PPAR&gamma; and therefore, together with the distinct tissue expression profile of this receptor, suggest potential differences in the function of PPAR&gamma; in fish compared with mammals

    Anti-obesity activity of diglyceride containing conjugated linoleic acid in C57BL/6J ob/ob mice

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    This study was to investigate the anti-obesity effects of diglyceride (DG)-conjugated linoleic acid (CLA) containing 22% CLA as fatty acids in C57BL/6J ob/ob male mice. There were four experimental groups including vehicle control, DG, CLA, and DG-CLA. The test solutions of 750 mg/kg dose were orally administered to the mice everyday for 5 weeks. CLA treatments significantly decreased mean body weight in the obese mice throughout the experimental period compared to the control (p < 0.01). All test solutions significantly decreased the levels of triglyceride, glucose and free fatty acids in the serum compared with control (p < 0.05). The levels of total cholesterol were also significantly reduced in DG and DG-CLA groups compared with the control group (p < 0.05). CLA significantly decreased weights of renal and epididymal fats compared with the control (p < 0.05). DG and DG-CLA also significantly decreased the epididymal fat weights compared with the control (p < 0.05). A remarkable decrease in the number of lipid droplets and fat globules was observed in the livers of mice treated with DG, CLA, and DG-CLA compared to control. Treatments of DG and CLA actually increased the expression of peroxisome proliferator-activated receptor gamma. These results suggest that DG-CLA containing 22% CLA have a respectable anti-obesity effect by controlling serum lipids and fat metabolism

    LLM3D: a log-linear modeling-based method to predict functional gene regulatory interactions from genome-wide expression data

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    All cellular processes are regulated by condition-specific and time-dependent interactions between transcription factors and their target genes. While in simple organisms, e.g. bacteria and yeast, a large amount of experimental data is available to support functional transcription regulatory interactions, in mammalian systems reconstruction of gene regulatory networks still heavily depends on the accurate prediction of transcription factor binding sites. Here, we present a new method, log-linear modeling of 3D contingency tables (LLM3D), to predict functional transcription factor binding sites. LLM3D combines gene expression data, gene ontology annotation and computationally predicted transcription factor binding sites in a single statistical analysis, and offers a methodological improvement over existing enrichment-based methods. We show that LLM3D successfully identifies novel transcriptional regulators of the yeast metabolic cycle, and correctly predicts key regulators of mouse embryonic stem cell self-renewal more accurately than existing enrichment-based methods. Moreover, in a clinically relevant in vivo injury model of mammalian neurons, LLM3D identified peroxisome proliferator-activated receptor γ (PPARγ) as a neuron-intrinsic transcriptional regulator of regenerative axon growth. In conclusion, LLM3D provides a significant improvement over existing methods in predicting functional transcription regulatory interactions in the absence of experimental transcription factor binding data

    Mitochondrial Oxidative Stress Alters a Pathway in Caenorhabditis elegans Strongly Resembling That of Bile Acid Biosynthesis and Secretion in Vertebrates

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    Mammalian bile acids (BAs) are oxidized metabolites of cholesterol whose amphiphilic properties serve in lipid and cholesterol uptake. BAs also act as hormone-like substances that regulate metabolism. The Caenorhabditis elegans clk-1 mutants sustain elevated mitochondrial oxidative stress and display a slow defecation phenotype that is sensitive to the level of dietary cholesterol. We found that: 1) The defecation phenotype of clk-1 mutants is suppressed by mutations in tat-2 identified in a previous unbiased screen for suppressors of clk-1. TAT-2 is homologous to ATP8B1, a flippase required for normal BA secretion in mammals. 2) The phenotype is suppressed by cholestyramine, a resin that binds BAs. 3) The phenotype is suppressed by the knock-down of C. elegans homologues of BA–biosynthetic enzymes. 4) The phenotype is enhanced by treatment with BAs. 5) Lipid extracts from C. elegans contain an activity that mimics the effect of BAs on clk-1, and the activity is more abundant in clk-1 extracts. 6) clk-1 and clk-1;tat-2 double mutants show altered cholesterol content. 7) The clk-1 phenotype is enhanced by high dietary cholesterol and this requires TAT-2. 8) Suppression of clk-1 by tat-2 is rescued by BAs, and this requires dietary cholesterol. 9) The clk-1 phenotype, including the level of activity in lipid extracts, is suppressed by antioxidants and enhanced by depletion of mitochondrial superoxide dismutases. These observations suggest that C. elegans synthesizes and secretes molecules with properties and functions resembling those of BAs. These molecules act in cholesterol uptake, and their level of synthesis is up-regulated by mitochondrial oxidative stress. Future investigations should reveal whether these molecules are in fact BAs, which would suggest the unexplored possibility that the elevated oxidative stress that characterizes the metabolic syndrome might participate in disease processes by affecting the regulation of metabolism by BAs
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