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- Øvrelid, Lilja, 1978
(author)
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Argument Differentiation. Soft constraints and data-driven models
- 2008
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Doctoral thesis (other academic/artistic)abstract
- The ability to distinguish between different types of arguments is central to syntactic analysis, whether studied from a theoretical or computational point of view. This thesis investigates the influence and interaction of linguistic properties of syntactic arguments in argument differentiation. Cross-linguistic generalizations regarding these properties often express probabil... meristic, or soft, constraints, rather than absolute requirements on syntactic structure. In language data, we observe frequency effects in the realization of syntactic arguments. We propose that argument differentiation can be studied using data-driven methods which directly express the relationship between frequency distributions in language data and linguistic categories. The main focus in this thesis is on the formulation and empirical evaluation of linguistically motivated features for data-driven modeling. Based on differential properties of syntactic arguments in Scandinavian language data, we investigate the linguistic factors involved in argument differentiation from two different perspectives. We study automatic acquisition of the lexical semantic category of animacy and show that statistical tendencies in argument differentiation supports automatic classification of unseen nouns. The classification is furthermore robust, generalizable across machine learning algorithms, as well as scalable to larger data sets. We go on to perform a detailed study of the influence of a range of different linguistic properties, such as animacy, definiteness and finiteness, on argument disambiguation in data-driven dependency parsing of Swedish. By including features capturing these properties in the representations used by the parser, we are able to improve accuracy significantly, and in particular for the analysis of syntactic arguments. The thesis shows how the study of soft constraints and gradience in language can be carried out using data-driven models and argues that these provide a controlled setting where different factors may be evaluated and their influence quantified. By focusing on empirical evaluation, we come to a better understanding of the results and implications of the datadriven models and furthermore show how linguistic motivation in turn can lead to improved computational models.
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| 2. |
- Bhandage, Amol K., 1988-, et al.
(author)
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GABA-A and NMDA receptor subunit mRNA expression is altered in the caudate but not the putamen of the postmortem brains of alcoholics
- 2014
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In: Frontiers in Cellular Neuroscience. - : Frontiers. - 1662-5102. ; 8
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Journal article (peer-reviewed)abstract
- Chronic consumption of alcohol by humans has been shown to lead to impairment of executive and cognitive functions. Here, we have studied the mRNA expression of ion channel receptors for glutamate and GABA in the dorsal striatum of post-mortem brains from alcoholics (n = 29) and normal controls (n = 29), with the focus on the caudate nucleus that is associated with the frontal cortex executive functions and automatic thinking and on the putamen area that is linked to motor cortices and automatic movements. The results obtained by qPCR assay revealed significant changes in the expression of specific excitatory ionotropic glutamate and inhibitory GABA-A receptor subunit genes in the caudate but not the putamen. Thus, in the caudate we found reduced levels of mRNAs encoding the GluN2A glutamate receptor and the δ, ε, and ρ2 GABA-A receptor subunits, and increased levels of the mRNAs encoding GluD1, GluD2, and GABA-A γ1 subunits in the alcoholics as compared to controls. Interestingly in the controls, 11 glutamate and 5 GABA-A receptor genes were more prominently expressed in the caudate than the putamen (fold-increase varied from 1.24 to 2.91). Differences in gene expression patterns between the striatal regions may underlie differences in associated behavioral outputs. Our results suggest an altered balance between caudate-mediated voluntarily controlled and automatic behaviors in alcoholics, including diminished executive control on goal-directed alcohol-seeking behavior.
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| 3. |
- Bhandage, Amol K., 1988-, et al.
(author)
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Depression, GABA, and Age Correlate with Plasma Levels of Inflammatory Markers
- 2019
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In: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 20:24
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Journal article (peer-reviewed)abstract
- Immunomodulation is increasingly being recognised as a part of mental diseases. Here, we examined whether levels of immunological protein markers changed with depression, age, or the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). An analysis of plasma samples from patients with a major depressive episode and control blood donors (CBD) revealed the expression of 67 inflammatory markers. Thirteen of these markers displayed augmented levels in patients compared to CBD. Twenty-one markers correlated with the age of the patients, whereas 10 markers correlated with the age of CBD. Interestingly, CST5 and CDCP1 showed the strongest correlation with age in the patients and CBD, respectively. IL-18 was the only marker that correlated with the MADRS-S scores of the patients. Neuronal growth factors (NGFs) were significantly enhanced in plasma from the patients, as was the average plasma GABA concentration. GABA modulated the release of seven cytokines in anti-CD3-stimulated peripheral blood mononuclear cells (PBMCs) from the patients. The study reveals significant changes in the plasma composition of small molecules during depression and identifies potential peripheral biomarkers of the disease.
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| 4. |
- Emerton, Rebecca, et al.
(author)
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Emergency flood bulletins for Cyclones Idai and Kenneth : A critical evaluation of the use of global flood forecasts for international humanitarian preparedness and response
- 2020
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In: International Journal of Disaster Risk Reduction. - : ELSEVIER. - 2212-4209. ; 50
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Journal article (peer-reviewed)abstract
- Humanitarian disasters such as Typhoon Haiyan (SE Asia, 2013) and the Horn of Africa drought (2011-2012) are examples of natural hazards that were predicted, but where forecasts were not sufficiently acted upon, leading to considerable loss of life. These events, alongside international adoption of the Sendai Framework for Disaster Risk Reduction, have motivated efforts to enable early action from early warnings. Through initiatives such as Forecast-based Financing (FbF) and the Science for Humanitarian Emergencies and Resilience (SHEAR) programme, progress is being made towards the use of science and forecasts to support international humanitarian organisations and governments in taking early action and improving disaster resilience. However, many challenges remain in using forecasts systematically for preparedness and response. The research community in place through SHEAR enabled the UK government's Department for International Development to task a collaborative group of scientists to produce probabilistic real-time flood forecast and risk bulletins, aimed at humanitarian decision-makers, for Cyclones Idai and Kenneth, which impacted Mozambique in 2019. The process of bulletin creation during Idai and Kenneth is reviewed and critically evaluated, including evaluation of the forecast information alongside evidence for how useful the bulletins were. In this context, this work seeks to navigate the "murky landscape" of national and international mandates, capacities, and collaborations for forecasting, early warning and anticipatory action, with the ultimate aim of finding out what can be done better in the future. Lessons learnt and future recommendations are discussed to enable better collaboration between producers and users of forecast information.
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| 5. |
- Ademark, Pia, et al.
(author)
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Multiple alpha-galactosidases from Aspergillus niger: purification, characterization, and substrate specificities
- 2001
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In: Enzyme and Microbial Technology. - 0141-0229. ; 29:6-7, s. 441-448
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Journal article (peer-reviewed)abstract
- Enzymes with α-galactosidase activity are produced by many organisms, often in multiple forms. Here we compare the biochemical and hydrolytic properties of four major α-galactosidase forms (α-gal I-IV) that were purified from the culture filtrate of Aspergillus niger. α-Gal II, III and IV appear to be isoforms of the same enzyme, and N-terminal amino acid sequence data suggest that they are closely related or identical to A. niger AglB in family 27 of the glycosyl hydrolases. α-Gal I is a completely different enzyme that belongs to family 36. α-Gal I had an isoelectric point of 4.15 and appears to be a tetramer composed of four 94-kDa subunits. α-Gal II, III and IV were dimers with monomeric molecular masses of 64 kDa and isoelectric points of 4.5, 4.7 and 4.8, respectively. α-Gal II-IV were stable when incubated for 17 h at 50°C and pH 2–5, whereas α-gal I was most stable at pH 5–6. All enzymes had maximal catalytic activity at pH 4.5 and 60°C, and hydrolyzed melibiose, raffinose and stachyose. α-Gal II-IV also degraded galactomanno-oligosaccharides and released 66% of the galactose side groups from polymeric locust bean gum galactomannan. α-Gal I released galactose from locust bean gum only in combination with A. niger β-mannosidase. Kinetic experiments showed that α-gal I hydrolyzed p-nitrophenyl-α-Image-galactopyranoside and melibiose more efficiently than α-gal II-IV. The distinct hydrolytic and biochemical properties of α-gal I and α-gal II-IV further signifies the difference between α-galactosidases of family 27 and 36.
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