180 research outputs found
Modelling the Lexicon in Unsupervised Part of Speech Induction
Automatically inducing the syntactic part-of-speech categories for words in
text is a fundamental task in Computational Linguistics. While the performance
of unsupervised tagging models has been slowly improving, current
state-of-the-art systems make the obviously incorrect assumption that all
tokens of a given word type must share a single part-of-speech tag. This
one-tag-per-type heuristic counters the tendency of Hidden Markov Model based
taggers to over generate tags for a given word type. However, it is clearly
incompatible with basic syntactic theory. In this paper we extend a
state-of-the-art Pitman-Yor Hidden Markov Model tagger with an explicit model
of the lexicon. In doing so we are able to incorporate a soft bias towards
inducing few tags per type. We develop a particle filter for drawing samples
from the posterior of our model and present empirical results that show that
our model is competitive with and faster than the state-of-the-art without
making any unrealistic restrictions.Comment: To be presented at the 14th Conference of the European Chapter of the
Association for Computational Linguistic
Administrative Law: Access to Review of Official Action-Standing Under the Florida Administrative Procedure Act
The Florida Administrative Procedure Act provides the vehicle through which Florida citizens can seek judicial or administrative review of the actions of administrative agencies. Before a litigant will be entitled to the benefits of these procedures, however, he must satisfy certain threshold standing requirements. This article critically examines Florida\u27s standing doctrine in the context of the structure and purpose of the Act and the major federal decisions that have developed many of the doctrine\u27s central principles
Dissolution of lead- and lead-arsenic-jarosites at pH 2 and 8 and 20 C: Insights from batch experiments
Lead- and Pb-As-jarosites are minerals common to acidic, sulphate-rich environments, including weathering zones of sulphide ore deposits and acid rock or acid mine drainage (ARD/AMD) sites, and often form on or near galena. The structures of these jarosites are based on linear tetrahedral-octahedral-tetrahedral (T-O-T) sheets, comprised of slightly distorted FeO6 octahedra and SO4 2- (-AsO4 3- in Pb-As-jarosites) tetrahedra. To better understand the dissolution mechanisms and products of the break down of Pb- and Pb-As-jarosite, preliminary batch dissolution experiments were conducted on synthetic Pb- and Pb-As-jarosite at pH 2 and 20 C, to mimic environments affected by ARD/AMD, and at pH 8 and 20 C, to simulate ARD/AMD environments recently remediated with slaked lime (Ca(OH)2). All four dissolutions are incongruent. Dissolution of Pb-jarosite at pH 2 yields aqueous Pb, Fe and SO4 2-. The pH 8 Pb-jarosite dissolution yields aqueous Pb, SO4 2- and poorly crystalline Fe(OH)3, which does not appear to resorb Pb or SO4 2-, possibly due to the low solution pH (3.44-3.54) at the end of the experiment. The pH 2 and 8 dissolutions of Pb-As-jarosite result in the formation of secondary compounds (poorly crystalline PbSO4 for pH 2 dissolution; poorly crystalline PbSO4 and Fe(OH)3 for pH 8 dissolution), which may act as dissolution inhibitors after 250 to 300 h of dissolution. In the pH 2 dissolution, aqueous Fe, SO4 2- and AsO4 3- also form, and in the pH 8 dissolution, Fe(OH)3 precipitates then subsequently resorbs aqueous AsO4 3-. The dissolutions probably proceed by preferred dissolution of the A- and T-sites, which contain Pb, and SO4 2-and AsO4 3-, respectively, rather than Fe, which is sterically remote, within the T-O-T Pb- and Pb-As-jarosite structures.These data provide the foundation necessary for further, more detailed investigations into the dissolution of Pb- and Pb-As-jarosites
Mechanisms of goethite dissolution in the presence of desferrioxamine B and Suwannee River fulvic acid at pH 6.5
Siderophores are Fe3+ specific low MW chelating ligands secreted by microorganisms in response to Fe stress. Low MW organic acids such as oxalate have been shown to enhance siderophore mediated dissolution of Fe3+ oxides. However, the effect of fulvic acid presence on siderophore function remains unknown. We used batch dissolution experiments to investigate Fe release from goethite in the goethite-fulvic acid desferrioxamine B (goethite-SRFA-DFOB) ternary system. Experiments were conducted at pH 6.5 while varying reagent addition sequence. FTIR and UV-Vis spectroscopy were employed to characterise the Fe-DFOB, Fe-SRFA and DFOBâSRFA complexes. Iron released from goethite in the presence of SRFA alone was below detection limit. In the presence of both SRFA and DFOB, dissolved Fe increased with reaction time, presence of the DFOB-SRFA complex, and where SRFA was introduced prior to DFOB. FTIR data show that in the ternary system, Fe3+ is complexed primarily to oxygen of the DFOB hydroxamate group, whilst the carboxylate C=O of SRFA forms an electrostatic association with the
terminal NH3+ of DFOB. We propose that SRFA sorbed to goethite lowers the net positive charge of the oxide surface, thus facilitating adsorption of cationic DFOB and subsequent Fe3+ chelation and release. Furthermore, the sorbed SRFA weakens Fe-O bonds at the goethite surface, increasing the population of kinetically labile Fe. This work demonstrates the positive, though indirect role of SRFA in increasing the bioavailability of Fe3+
Radionuclide assessment of regional left ventricular function in acute myocardial infarction
To determine changes in global and regional left ventricular function following acute myocardial function, 17 patients underwent radionuclide angiography at 3 and 10 days post infarction. Five patients had nontransmural myocardial infarction and 12 had transmural infarction (six anterior and six inferior). There were no previous infarctions in 16 (94%) patients. Regional ejection fractions were calculated by dividing the left ventricle into four quadrants using the geometric center of the left ventricle on the end-diastolic frame as a reference point. At 3 days post infarction, 8 of 17 (47%) patients had an abnormality of global left ventricular ejection fraction (LVEF), whereas 16 of 17 (94%) patients had abnormalities of one or more regional ejection fractions (p p = NS). However, there were significant changes in 23 of 68 (34%) regional LVEFs. These changes did not relate to type, ECG location, creatine kinase (CK) size of infarction, or initial global LVEF. These data suggest that regional LVEF is a sensitive technique for identifying segmental dysfunction associated with myocardial infarction. In addition, significant changes occur in regional LV function during acute myocardial infarction despite stable serial global LV performance.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26327/1/0000414.pd
Building H.O.U.S.E (Healthy Outcomes Using a Supportive Environment): Exploring the Role of Affordable and Inclusive Housing for LGBTQIA+ Older Adults
Little is known about how permanent, inclusive, affordable, and supportive longâterm housing may affect the health of lowâincome lesbian, gay, bisexual, transgender, queer, intersex, asexual and/or another identity (LGBTQIA+) older adults. Focus group interviews were conducted with 21 older adults to explore the lived experiences and potential health benefits of living in a new LGBTQIA+âwelcoming senior housing. Participants reported that moving into the housing was associated with benefits for health and wellâbeing, especially for psychological health. Community, social support, and inâhouse services were particularly important. However, the combined nature of LGBTQIA+âwelcoming and older adult only housing evoked mixed feelings. Appropriate and accessible housing solutions are essential for LGBTQIA+ older adults and may help address health disparities for these populations
Synthesis, characterization and thermochemistry of synthetic PbâAs, PbâCu and PbâZn jarosites
The enthalpy of formation from the elements of well characterized Pb-As, Pb-Cu, and Pb-Zn synthetic jarosites, corresponding to chemical formulas (H3O)0.68±0.03Pb0.32±0.002Fe2.86±0.14(SO4)1.69±0.08(AsO4)0.31±0.02(OH)5.59±0.28(H2O)0.41±0.02, (H3O)0.67±0.03Pb0.33±0.02Fe2.71±0.14Cu0.25±0.01(SO4)2±0.00(OH)5.96±0.30(H2O)0.04±0.002 and (H3O)0.57±0.03Pb0.43±0.02Fe2.70±0.14Zn0.21±0.01(SO4)2±0.00(OH)5.95±0.30(H2O)0.05±0.002, was measured by high temperature oxide melt solution calorimetry and gave ÎH°f = -3691.2 ± 8.6 kJ/mol, ÎH°f = -3653.6 ± 8.2 kJ/mol, and ÎH°f = -3669.4 ± 8.4 kJ/mol, respectively. Using estimated entropies, the standard Gibbs free energy of formation from elements at 298 K ÎG°f of the three compounds were calculated to be -3164.8 ± 9.1 kJ/mol, -3131.4 ± 8.7 kJ/mol, and -3153.6 ± 8.9 kJ/mol, respectively. Based on these free energies, their logKsp values are -13.94 ± 1.89, -4.38 ± 1.81 and -3.75 ± 1.80, respectively. For this compounds, a log10{Pb2+} - pH diagram is presented. The diagram shows that the formation of Pb-As jarosite may decrease aqueous arsenic and lead concentrations to meet drinking water standards. The new thermodynamic data confirm that transformation of Pb-As jarosite to plumbojarosite is thermodynamically possible
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