An Injection with Tree Awareness: Adding Staircase Join to PostgreSQL

The syntactic wellformedness constraints of XML (opening and closing tags nest properly) imply that XML processors face the challenge to efficiently handle data that takes the shape of ordered, unranked trees. Although RDBMSs have originally been designed to manage table-shaped data, we propose their use as XML and XPath processors. In our setup, the database system employs a relational XML document encoding, the XPath accelerator [1], which maps information about the XML node hierarchy to a table, thus making it possible to evaluate XPath expressions on SQL hosts.\ud \ud Conventional RDBMSs, nevertheless, remain ignorant of many interesting properties of the encoded tree data, and were thus found to make no or poor use of these properties. This is why we devised a new join algorithm, staircase join [2], which incorporates the tree-specific knowledge required for an efficient SQL-based evaluation of XPath expressions. In a sense, this demonstration delivers the promise we have made at VLDB 2003 [2]: a notion of tree awareness can be injected into a conventional disk-based RDBMS kernel in terms of staircase join. The demonstration features a side-by-side comparison of both, an original and a staircase-join enhanced instance of PostgreSQL [4]. The required changes to\ud PostgreSQL were local, the achieved eect, however, is significant: the demonstration proves that this injection of tree awareness turns PostgreSQL into a high-performance XML processor that closely adheres to the XPath semantics

Competitive advantage from mandatory investments: An empirical study of Australian firms

Mandatory information system (IS) investments occur when government regulations require firms to alter their IS. These investments are additional expenditures added onto the initial expenditures of non-mandatory IS investments. Managers are concerned about associated costs and in an attempt to reduce the expenditures, most firms refrain from formal planning methods when mandatory investments are imposed upon them. Drawing on Henderson’s and Sifonis’ (1988) IS Planning and Investment Model as our theoretical lens, this paper argues that firms should re-consider this practice. It is hypothesised that formal planning methods are beneficial because they enable firms to combine mandatory and non-mandatory investments in such a way that competitive advantage can be achieved. We use a secondary dataset provided by the Australian government to test the hypotheses. Results show that only two out of three investigated formal planning methods are positively associated with competitive advantage. We conclude that in the special case of mandatory investments, formal methods are only beneficial if they incorporate information from the entire firm, rather than information from particular departments only

The state of the Martian climate

60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

The Impact of Orthodontic Bands on the Marginal Periodontium of Maxillary First Molars: A Retrospective Cross-Sectional Radiographic Analysis

Aim: Available information on the effect of orthodontic treatment on crestal alveolar bone levels measured in radiographs is contradictory. The aim of this study was to compare the alveolar bone level and periodontal ligament space of banded upper first molars to untreated controls. Materials and Methods: This retrospective cross-sectional radiographic study investigated alveolar bone levels of upper first molars of an orthodontic test group and an untreated control group of comparable age (15-16.25 years), using existing bitewing radiographs. Eighty-six individuals were included in each group. Three parameters were measured mesially and distally on both sides of the patient as follows: I) Alveolar Bone Level (ABL): measured as the distance between the cemento-enamel junction and the alveolar crest, II) the Periodontal Ligament Space (PLS): measured as the most coronal distance between the alveolar crest and the tooth surface, and III) angle between the lines (alveolar crests mesial and distal) and (cemento-enamel junction mesial and distal). Results: The mean duration of the orthodontic treatment in the test group was 2.5 years. The periodontal ligament space was statistically significantly wider on mesial areas of right molars (mean 0.2 mm, p<0.01), but there was no statistically significant difference found in the three other areas (distal part of the right molar, mesial and distal parts of the left molar). There was a statistically significant mean alveolar bone loss in the right and left mesial areas, respectively accounting for 0.3 mm (p<0.001) and 0.2 mm (p<0.01). No statistically significant alveolar bone loss was measured on the distal surfaces of the upper molars. The angle was wider on both sides for the test group (right p<0.001 and left p<0.05). Conclusions: A significant alveolar bone loss on the mesial tooth surface of upper first molars after orthodontic treatment was found with concurrent different levelling angles in the test group. On all other sites, no statistically significant changes were found. There was some minimal statistical significant alveolar bone loss after finishing treatment in patients who had orthodontic bands placed on their maxillary 1st molars, but no clinical significance was found

Analogues of cis- and transplatin with a rich solutionchemistry: Cis-[PtCl2(NH3)(1-MeC-N3)] and trans-[PtI2(NH3)(1-MeC-N3)]

Mono(nucleobase) complexes of the general composition cis-[PtCl(NH)L] with L=1-methylcytosine, 1-MeC (1 a) and L=1-ethyl-5-methylcytosine, as well as trans-[PtX(NH)(1-MeC)] with X=I (5 a) and X=Br (5 b) have been isolated and were characterized by X-ray crystallography. The Pt coordination occurs through the N3 atom of the cytosine in all cases. The diaqua complexes of compounds 1 a and 5 a, cis-[Pt(HO)(NH)(1-MeC)] and trans-[Pt(HO)(NH)(1-MeC)], display a rich chemistry in aqueous solution, which is dominated by extensive condensation reactions leading to μ-OH- and μ-(1-MeC-N3,N4)-bridged species and ready oxidation of Pt to mixed-valence state complexes as well as diplatinum(III) compounds, one of which was characterized by X-ray crystallography: h,t-[{Pt(NH)(OH)(1-MeC-N3,N4)}](NO).2 [NH](NO).2 HO. A combination of H NMR spectroscopy and ESI mass spectrometry was applied to identify some of the various species present in solution and the gas phase, respectively. As it turned out, mass spectrometry did not permit an unambiguous assignment of the structures of +1 cations due to the possibilities of realizing multiple bridging patterns in isomeric species, the occurrence of different tautomers, and uncertainties regarding the Pt oxidation states. Additionally, compound 1 a was found to have selective and moderate antiproliferative activity for a human cervix cancer line (SISO) compared to six other human cancer cell lines.This work was supported by the Deutsche Forschungsgemeinschaft. P.J.S.M. thanks the Spanish Ministry of Economy and Competitiveness for funding through the Ramón y Cajal program.Peer Reviewe

Analogues of Cis- and Transplatin with a Rich Solution Chemistry:cis-[PtCl2(NH3)(1-MeC-N3)] andtrans-[PtI2(NH3)(1-MeC-N3)]

Mono(nucleobase) complexes of the general composition cis-[PtCl2(NH3)L] with L=1-methylcytosine, 1-MeC (1 a) and L=1-ethyl-5-methylcytosine, as well as trans-[PtX2(NH3)(1-MeC)] with X=I (5 a) and X=Br (5 b) have been isolated and were characterized by X-ray crystallography. The Pt coordination occurs through the N3 atom of the cytosine in all cases. The diaqua complexes of compounds 1 a and 5 a, cis-[Pt(H2O)2(NH3)(1-MeC)]2+ and trans-[Pt(H2O)2(NH3)(1-MeC)]2+, display a rich chemistry in aqueous solution, which is dominated by extensive condensation reactions leading to μ-OH- and μ-(1-MeC−-N3,N4)-bridged species and ready oxidation of Pt to mixed-valence state complexes as well as diplatinum(III) compounds, one of which was characterized by X-ray crystallography: h,t-[{Pt(NH3)2(OH)(1-MeC−-N3,N4)}2](NO3)2⋅2 [NH4](NO3)⋅2 H2O. A combination of 1H NMR spectroscopy and ESI mass spectrometry was applied to identify some of the various species present in solution and the gas phase, respectively. As it turned out, mass spectrometry did not permit an unambiguous assignment of the structures of +1 cations due to the possibilities of realizing multiple bridging patterns in isomeric species, the occurrence of different tautomers, and uncertainties regarding the Pt oxidation states. Additionally, compound 1 a was found to have selective and moderate antiproliferative activity for a human cervix cancer line (SISO) compared to six other human cancer cell lines