352 research outputs found

    Handwritten digit recognition by bio-inspired hierarchical networks

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    The human brain processes information showing learning and prediction abilities but the underlying neuronal mechanisms still remain unknown. Recently, many studies prove that neuronal networks are able of both generalizations and associations of sensory inputs. In this paper, following a set of neurophysiological evidences, we propose a learning framework with a strong biological plausibility that mimics prominent functions of cortical circuitries. We developed the Inductive Conceptual Network (ICN), that is a hierarchical bio-inspired network, able to learn invariant patterns by Variable-order Markov Models implemented in its nodes. The outputs of the top-most node of ICN hierarchy, representing the highest input generalization, allow for automatic classification of inputs. We found that the ICN clusterized MNIST images with an error of 5.73% and USPS images with an error of 12.56%

    Four Work-Ins by Australian Journalists, 1944-80

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    During industrial disputes with employers between 1944 and 1980 the Australian Journalist's Association occasionally turned to the tactic of the work-in, producing wild cat newspapers during strikes in Sydney. These newspapers (The News, and The Clarion) exemplified problematic elements of the work-in as a working-class strategy. While single incident studies of the work-in have been conducted in Australia, the Australian Journalist Association work-ins present a time series of struggle. This time series allows for a broader evaluation of the radical content of the work-in and indicates that the tactic can become systematised, less radical, and less participatory when not connected to a broader generation of workplace radical behaviour by workers. In short: the work-in, much like the strike or go slow, can become a tame cat tactic – it is not inherently transgressive or opposed to capitalist production. Expectedly, the first work-ins were more radical in scope, presenting a newspaper which fully duplicated the commodity produced under capitalist control and in some ways exceeded the scope presented by capitalist organised journalism in both a material and a cultural sense. However, this radical economic potential dissipated by the end of the time series of work-ins. Instead of providing an alternative commodity fit for market, the tactic produced propaganda pieces aimed primarily at the members of the community who would be predisposed to favour the journalist's case. The 1980s Clarion was not a daily newspaper of news, sport, racing, women's interest, classifieds, and general opinion. This change will be explained in terms of human causes such as skills loss, production process causes such as computerisation and wire services, and broader social causes such as the changing role of the newspaper in Australian society.The symposium is organised on behalf of AAHANZBS by the Business and Labour History Group, The University of Sydney, with the financial support of the University’s Faculty of Economics and Business

    The Nuclear Transcription Factor PKNOX2 Is a Candidate Gene for Substance Dependence in European-Origin Women

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    Substance dependence or addiction is a complex environmental and genetic disorder that results in serious health and socio-economic consequences. Multiple substance dependence categories together, rather than any one individual addiction outcome, may explain the genetic variability of such disorder. In our study, we defined a composite substance dependence phenotype derived from six individual diagnoses: addiction to nicotine, alcohol, marijuana, cocaine, opiates or other drugs as a whole. Using data from several genomewide case-control studies, we identified a strong (Odds ratio  = 1.77) and significant (p-value = 7E-8) association signal with a novel gene, PBX/knotted 1 homeobox 2 (PKNOX2), on chromosome 11 with the composite phenotype in European-origin women. The association signal is not as significant when individual outcomes for addiction are considered, or in males or African-origin population. Our findings underscore the importance of considering multiple addiction types and the importance of considering population and gender stratification when analyzing data with heterogeneous population

    Algorithms for learning parsimonious context trees

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    Parsimonious context trees, PCTs, provide a sparse parameterization of conditional probability distributions. They are particularly powerful for modeling context-specific independencies in sequential discrete data. Learning PCTs from data is computationally hard due to the combinatorial explosion of the space of model structures as the number of predictor variables grows. Under the score-and-search paradigm, the fastest algorithm for finding an optimal PCT, prior to the present work, is based on dynamic programming. While the algorithm can handle small instances fast, it becomes infeasible already when there are half a dozen four-state predictor variables. Here, we show that common scoring functions enable the use of new algorithmic ideas, which can significantly expedite the dynamic programming algorithm on typical data. Specifically, we introduce a memoization technique, which exploits regularities within the predictor variables by equating different contexts associated with the same data subset, and a bound-and-prune technique, which exploits regularities within the response variable by pruning parts of the search space based on score upper bounds. On real-world data from recent applications of PCTs within computational biology the ideas are shown to reduce the traversed search space and the computation time by several orders of magnitude in typical cases.Peer reviewe

    The genetic basis of DOORS syndrome: an exome-sequencing study.

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    Deafness, onychodystrophy, osteodystrophy, mental retardation, and seizures (DOORS) syndrome is a rare autosomal recessive disorder of unknown cause. We aimed to identify the genetic basis of this syndrome by sequencing most coding exons in affected individuals

    The concept of "compartment allergy": prilocaine injected into different skin layers

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    We herein present a patient with delayed-type allergic hypersensitivity against prilocaine leading to spreading eczematous dermatitis after subcutaneous injections for local anesthesia with prilocaine. Prilocaine allergy was proven by positive skin testing and subcutaneous provocation, whereas the evaluation of other local anesthetics - among them lidocaine, articaine and mepivacaine - did not exhibit any evidence for cross-reactivity

    Expression profiling identifies novel candidate genes for ethanol sensitivity QTLs

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    The Inbred Long Sleep (ILS) and Inbred Short Sleep (ISS) mouse strains have a 16-fold difference in duration of loss of the righting response (LORR) following administration of a sedative dose of ethanol. Four quantitative trait loci (QTLs) have been mapped in these strains for this trait. Underlying each of these QTLs must be one or more genetic differences (polymorphisms in either gene coding or regulatory regions) influencing ethanol sensitivity. Because prior studies have tended to focus on differences in coding regions, genome-wide expression profiling in cerebellum was used here to identify candidate genes for regulatory region differences in these two strains. Fifteen differentially expressed genes were found that map to the QTL regions and polymorphisms were identified in the promoter regions of four of these genes by direct sequencing of ILS and ISS genomic DNA. Polymorphisms in the promoters of three of these genes, Slc22a4, Rassf2, and Tax1bp3, disrupt putative transcription factor binding sites. Slc22a4 and another candidate, Xrcc5, have human orthologs that map to genomic regions associated with human ethanol sensitivity in genetic linkage studies. These genes represent novel candidates for the LORR phenotype and provide new targets for future studies into the neuronal processes underlying ethanol sensitivity

    Potentiation of anti-cancer drug activity at low intratumoral pH induced by the mitochondrial inhibitor m-iodobenzylguanidine (MIBG) and its analogue benzylguanidine (BG)

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    Tumour-selective acidification is of potential interest for enhanced therapeutic gain of pH sensitive drugs. In this study, we investigated the feasibility of a tumour-selective reduction of the extracellular and intracellular pH and their effect on the tumour response of selected anti-cancer drugs. In an in vitro L1210 leukaemic cell model, we confirmed enhanced cytotoxicity of chlorambucil at low extracellular pH conditions. In contrast, the alkylating drugs melphalan and cisplatin, and bioreductive agents mitomycin C and its derivative EO9, required low intracellular pH conditions for enhanced activation. Furthermore, a strong and pH-independent synergism was observed between the pH-equilibrating drug nigericin and melphalan, of which the mechanism is unclear. In radiation-induced fibrosarcoma (RIF-1) tumour-bearing mice, the extracellular pH was reduced by the mitochondrial inhibitor m-iodobenzylguanidine (MIBG) or its analogue benzylguanidine (BG) plus glucose. To simultaneously reduce the intracellular pH, MIBG plus glucose were combined with the ionophore nigericin or the Na+/H+ exchanger inhibitor amiloride and the Na+-dependent HCO3−/Cl−exchanger inhibitor 4,4′-diisothiocyanostilbene-2,2′-disulphonic acid (DIDS). Biochemical studies confirmed an effective reduction of the extracellular pH to approximately 6.2, and anti-tumour responses to the interventions indicated a simultaneous reduction of the intracellular pH below 6.6 for at least 3 h. Combined reduction of extra- and intracellular tumour pH with melphalan increased the tumour regrowth time to 200% of the pretreatment volume from 5.7 ± 0.6 days for melphalan alone to 8.1 ± 0.7 days with pH manipulation (P< 0.05). Mitomycin C related tumour growth delay was enhanced by the combined interventions from 3.8 ± 0.5 to 5.2 ± 0.5 days (P< 0.05), but only in tumours of relatively large sizes. The interventions were non-toxic alone or in combination with the anti-cancer drugs and did not affect melphalan biodistribution. In conclusion, we have developed non-toxic interventions for sustained and selective reduction of extra- and intracellular tumour pH which potentiated the tumour responses to selected anti-cancer drugs. 1999 Cancer Research Campaig

    A Functional NQO1 609C>T Polymorphism and Risk of Gastrointestinal Cancers: A Meta-Analysis

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    Background: The functional polymorphism (rs1800566) in the NQO1 gene, a 609C.T substitution, leading to proline-toserine amino-acid and enzyme activity changes, has been implicated in cancer risk, but individually published studies showed inconclusive results. Methodology/Principal Findings: We performed a meta-analysis of 20 publications with a total of 5,491 cases and 5,917 controls, mainly on gastrointestinal (GI) cancers. We summarized the data on the association between the NQO1 609C.T polymorphism and risk of GI cancers and performed subgroup analyses by ethnicity, cancer site, and study quality. We found that the variant CT heterozygous and CT/TT genotypes of the NQO1 609 C.T polymorphism were associated with a modestly increased risk of GI cancers (CT vs. CC: OR = 1.10, 95 % CI = 1.01 – 1.19, P heterogeneity = 0.27, I 2 = 0.15; CT/TT vs. CC: OR = 1.11, 95%CI = 1.02 – 1.20, Pheterogeneity = 0.14; I 2 = 0.27). Following further stratified analyses, the increased risk was only observed in subgroups of Caucasians, colorectal cancer in Caucasians, and high quality studies. Conclusions: This meta-analysis suggests that the NQO1 609T allele is a low-penetrance risk factor for GI cancers. Although the effect on GI cancers may be modified by ethnicity and cancer sites, small sample seizes of the subgroup analyse
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