title: Hydrogen bonding in hydroxymethylphosphine chalcogenides

authors: Goodwin, Nicholas J.

subjects: Crystal structures

abstract: Hydrogen bonding in the phosphine chalcogenide series Ph2P(X)CH2OH (X=O, 1; S, 2; Se, 3) has been investigated by single crystal X-ray crystallography. While the phosphine oxide exhibits a dimer motif, the sulfide and selenide form infinite chains; in all cases hydrogen bonding is from the OH group to the phosphine chalcogenide heteroatom. The trend in the hydrogen bond angle for OH X-P, which is 117, 87 and 84° for the oxide, sulfide and selenide, respectively, is explained with respect to the geometry of electron density on the phosphine chalcogenide heteroatom.

text: Hydrogen bonding in hydroxymethylphosphine chalcogenides Hydrogen bonding in the phosphine chalcogenide series Ph2P(X)CH2OH (X=O, 1; S, 2; Se, 3) has been investigated by single crystal X-ray crystallography. While the phosphine oxide exhibits a dimer motif, the sulfide and selenide form infinite chains; in all cases hydrogen bonding is from the OH group to the phosphine chalcogenide heteroatom. The trend in the hydrogen bond angle for OH X-P, which is 117, 87 and 84° for the oxide, sulfide and selenide, respectively, is explained with respect to the geometry of electron density on the phosphine chalcogenide heteroatom.

year: 2002-06-01

title: Efficient algorithms for conditional independence inference

authors: Bouckaert, Remco R.

subjects: computer science

abstract: The topic of the paper is computer testing of (probabilistic) conditional independence (CI) implications by an algebraic method of structural imsets. The basic idea is to transform (sets of) CI statements into certain integral vectors and to verify by a computer the corresponding algebraic relation between the vectors, called the independence implication. We interpret the previous methods for computer testing of this implication from the point of view of polyhedral geometry. However, the main contribution of the paper is a new method, based on linear programming (LP). The new method overcomes the limitation of former methods to the number of involved variables. We recall/describe the theoretical basis for all four methods involved in our computational experiments, whose aim was to compare the efficiency of the algorithms. The experiments show that the LP method is clearly the fastest one. As an example of possible application of such algorithms we show that testing inclusion of Bayesian network structures or whether a CI statement is encoded in an acyclic directed graph can be done by the algebraic method.

text: Efficient algorithms for conditional independence inference The topic of the paper is computer testing of (probabilistic) conditional independence (CI) implications by an algebraic method of structural imsets. The basic idea is to transform (sets of) CI statements into certain integral vectors and to verify by a computer the corresponding algebraic relation between the vectors, called the independence implication. We interpret the previous methods for computer testing of this implication from the point of view of polyhedral geometry. However, the main contribution of the paper is a new method, based on linear programming (LP). The new method overcomes the limitation of former methods to the number of involved variables. We recall/describe the theoretical basis for all four methods involved in our computational experiments, whose aim was to compare the efficiency of the algorithms. The experiments show that the LP method is clearly the fastest one. As an example of possible application of such algorithms we show that testing inclusion of Bayesian network structures or whether a CI statement is encoded in an acyclic directed graph can be done by the algebraic method.

year: 2010

title: Tū Māori Ake: Seeking which is above.

authors: Maxwell, Te Kahautu

abstract: Te Waka Āwhina 2015 Seeking that which is above Kaupapa - Philosophy o Aotearoa “Tū Māori ake” E ngā mana, e ngā reo, e ngā karangatanga, nei rā te powhiri ki a koutou katoa ‘MĀ TE MĀORI, MŌ TE MĀORI’ Te Waka Āwhina o Aotearoa National Training Hui by Māori for Māori within local government Āwhea: 2 – 4 February 2015 Ki whea: The Gallagher Academy of Performing Arts, The University of Waikato, Hamilton Hau kāinga: Te Puku o te Ika.

text: Tū Māori Ake: Seeking which is above. Te Waka Āwhina 2015 Seeking that which is above Kaupapa - Philosophy o Aotearoa “Tū Māori ake” E ngā mana, e ngā reo, e ngā karangatanga, nei rā te powhiri ki a koutou katoa ‘MĀ TE MĀORI, MŌ TE MĀORI’ Te Waka Āwhina o Aotearoa National Training Hui by Māori for Māori within local government Āwhea: 2 – 4 February 2015 Ki whea: The Gallagher Academy of Performing Arts, The University of Waikato, Hamilton Hau kāinga: Te Puku o te Ika.

year: 2015-02-03