DATA CONSTRUCTORS: ON THE INTEGRATION OF RULES AND RELATIONS

Although the goals and means of rule-based and data-based systems are too different to be fully integrated at the present time, it seems appropriate to investigate a closer integration of language constructs and a better cooperation of execution models for both kinds of approaches. In this paper, we propose a new language construct called constructor that â when applied to a base relation â causes relation membership to become true for all tuples constructable through the predicates provided by the constructor definition. The approach is shown to provide expressive power at least equivalent to PROLOG's declarative semantics while blending well both with a strongly typed modular programming language and with a relational calculus query formalism. A three-step compilation, optimization, and evaluation methodology for expressions with constructed relations is described that integrates constructors with the surrounding database programming environment. In particular, many recursive queries can be evaluated more efficiently within the set-construction framework of database systems than with proof-oriented methods typical for a rule-based approach.Information Systems Working Papers Serie

LICC: L-BLP25 in patients with colorectal carcinoma after curative resection of hepatic metastases--a randomized, placebo-controlled, multicenter, multinational, double-blinded phase II trial

Background: 15-20% of all patients initially diagnosed with colorectal cancer develop metastatic disease and surgical resection remains the only potentially curative treatment available. Current 5-year survival following R0-resection of liver metastases is 28-39%, but recurrence eventually occurs in up to 70%. To date, adjuvant chemotherapy has not improved clinical outcomes significantly. The primary objective of the ongoing LICC trial (L-BLP25 In Colorectal Cancer) is to determine whether L-BLP25, an active cancer immunotherapy, extends recurrence-free survival (RFS) time over placebo in colorectal cancer patients following R0/R1 resection of hepatic metastases. L-BLP25 targets MUC1 glycoprotein, which is highly expressed in hepatic metastases from colorectal cancer. In a phase IIB trial, L-BLP25 has shown acceptable tolerability and a trend towards longer survival in patients with stage IIIB locoregional NSCLC. Methods: This is a multinational, phase II, multicenter, randomized, double-blind, placebo-controlled trial with a sample size of 159 patients from 20 centers in 3 countries. Patients with stage IV colorectal adenocarcinoma limited to liver metastases are included. Following curative-intent complete resection of the primary tumor and of all synchronous/metachronous metastases, eligible patients are randomized 2:1 to receive either L-BLP25 or placebo. Those allocated to L-BLP25 receive a single dose of 300 mg/m2 cyclophosphamide (CP) 3 days before first L-BLP25 dose, then primary treatment with s.c. L-BLP25 930 mug once weekly for 8 weeks, followed by s.c. L-BLP25 930 mug maintenance doses at 6-week (years 1&2) and 12-week (year 3) intervals unless recurrence occurs. In the control arm, CP is replaced by saline solution and L-BLP25 by placebo. Primary endpoint is the comparison of recurrence-free survival (RFS) time between groups. Secondary endpoints are overall survival (OS) time, safety, tolerability, RFS/OS in MUC-1 positive cancers. Exploratory immune response analyses are planned. The primary endpoint will be assessed in Q3 2016. Follow-up will end Q3 2017. Interim analyses are not planned. Discussion: The design and implementation of such a vaccination study in colorectal cancer is feasible. The study will provide recurrence-free and overall survival rates of groups in an unbiased fashion. Trial Registration EudraCT Number 2011-000218-2

Movement of MTBE through soil after groundwater contamination

Since the late seventies, methyl-tert-butyl ether (MTBE) has become one of the most widely produced chemicals in Europe and the USA due to its use as a fuel additive. MTBE was first used as a substitute for the environmental poison tetraethyl lead because of its anti-knock properties. Statutory requirements for minimum volumes of oxygen-containing additives in motor fuels, to protect the atmosphere against the climate-relevant trace gases carbon monoxide (CO) and ozone (O$_{3}$), greatly increased the demand for MTBE in the USA. One consequence was an increasing number of groundwater and soil contaminations as well as complaints of damage to health associated with MTBE. Since the air had been kept clean at the expense of the groundwater and the soil, the use of MTBE is prohibited in the USA after 2003. In Europe increased numbers of MTBE-contaminations in the groundwater and surface waters have been reported. Goal of this project was the investigation of the MTBE mass transport into the atmosphere after a contamination of the groundwater. For this studies a tripartite experimental concept was selected: First of all, a soil column experimental set-up for studying mass transport in undisturbed soil monoliths was designed, constructed and validated. With this facility it was possible to create under defined and reproducible experimental conditions an aquifer below the soilcore, variable in height, in which a contamination with MTBE had been simulated in a real concentration range of 100 to 200 mg L$^{-1}$. A stream of air flowed over the soil surface through the artificial atmosphere, and was collected and analysed with respect to the composition of volatile organic chemicals. Adsorption onto multibed solid adsorbent material with subsequent thermal desorption GC/MS analysis was developed for air collection and displayed good sampling performance with excellent detection limits. The groundwater samples were analysed by radioactivity-HPLC, -GPC or a new direct injection-GC/MS analytical technique. For this liquid-injection-methods the detection limit still has to be improved. In the first experiment, up to 47 ppb (170 ng m$^{-3}$) of MTBE was detected in the air. MTBE was not continuously recovered in the air but only occurred in pulses. Maximum values were measured, in particular, in the first few days. The mass transfer rates through the soil into the atmosphere were in the region of 1.94 ± 1.88 μg m$^{-2}$ h$^{-1}$ in the first experiment with an equilibrium value of approx. 0.45 ± 0.02 μg m$^{-2}$ h$^{-1}$. In the second experiment with [α,α'-$^{14}$C] MTBE, only low volatilisation was measurable. At the same time, the water balance in the experimental system was also recorded, which enabled a qualitative relation to the MTBE loss to be established. The simulated aquifer was redesigned for a scale-up experiment and also the air sampler adapted for volatile hydrocarbons at the field like wind tunnel with a lysimeter. The new sampling unit was validated in several preliminary experiments and displayed good collecting efficiency for the high volume flows applied. Analogously to the second column experiment, over an experimental period of 4 weeks hardly any mass transport of MTBE through the soil was determined. The recovery rate in both experiments with $^{14}$C-MTBE was in the region of 83 to 102 % of the applied radioactivity (AR). As described in the literature only slight adsorption to the soil particles was found for MTBE. Since the soil columns and the lysimeter represented a compartment of the ecosystem with functioning microflora, the microbial aerobic degradation in the soil was determined in laboratory studies. A maximum mineralisation of 1.6 % AR was detected as a function of the previous contaminations of the soil and the soil type. Moreover, rapid volatilisation of the MTBE from the surface took place perceptibly reducing the bioavailability. The results obtained were readily applicable to the transport studies

Umweltverhalten von MTBE nach Grundwasserkontamination

Since the late seventies, methyl-tert-butyl ether (MTBE) has become one of the mort widely produced chemicals in Europe and the USA due to its use as a fuel additive. MTBE was first used as a substitute for the environmental poison tetraethyl lead because of its anti-knock properties. Statutory requirements for minimum volumes of oxygen-containing additives in motor fuels, to protect the atmosphere against the cl imate-relevant trace gases carbon monoxide (CO) and ozone (Os), greatly increased the demand for MTBE in the USA. One consequence was an increasing number of groundwater and soil contaminations as well as complaints of damage to health associated with MTBE. Since the air had been kept clean at the expense of the groundwater and the soil, the use of MTBE is prohibited in the USA after 2003. In Europe increased numbers of MTBE-contaminations in the groundwater and surface waters have been reported. Goal of this PhD thesis was the investigation of the MTBE mass transport into the atmosphere after a contamination of the groundwater. For this studies a tripartite experimental concept was selected: First of all, a soil column experimental setup for studying mass transport in undisturbed soil monoliths was designed, constructed and validated. With this facility it was possible to create under defined and reproducible experimental conditions an aquifer below the soilcore, variable in height, in which a contamination with MTBE had been simulated in a real concentration range of 100 to 200 mg L$^{-1}$. A stream of air flowed over the soil surface through the artificial atmosphere, and was collected and analysed with respect to the composition of volatile organic chemicals. Adsorption onto multibed solid adsorbent material with subsequent thermodesorption GC/MS analysis was developed for air collection and displayed good sampling performance with excellent detection limits. The groundwater samples were analysed by radioactivity-HPLC, -GPC or a new direct injection- GC/MS analytical technique. For this liquid-injection-methods the detection limit still has to be improved. In the first experiment, up to 47 ppb (170 ng m$^{-3}$) of MTBE was detected in the air. MTBE was not continuously recovered in the air but only occurred in pulses. Maximum values were measured, in particular, in the first few days. The mass transfer rates through the soil into the atmosphere were in the region of 1.94 ± 1.88 $\mu$g m$^{-2}$ h$^{-1}$ in the first experiment with an equilibrium value of approx . 0.45 ± 0.02 $\mu$g m$^{-2}$ h$^{-1}$. In the second experiment with [$\alpha$,$\alpha$'-$^{14}$M] MTBE, only low volatilization was measurable. At the same time, the water balance in the experimental System was also recorded, which enabled a qualitative relation to the MTBE loss to be established. The simulated aquifer was redesigned for a scale-up experiment and also the air sampler adapted for volatile hydrocarbons at the fieldlike wind tunnel with a lysimeter. The new sampling unit was validated in several preliminary experiments and displayed good collecting efficiency for the high volume flows applied. Analogously to the second column experiment, over an experimental period of 4 weeks hardly any mass transport of MTBE through the soil was determined. The recovery rate in both experiments with $^{14}$C-MTBE was in the region of 83 to 102 % of the applied radioactivity (AR). As described in the literature only slight adsorption to the soil particles was found for MTBE. Since the soil columns and the lysimeter represented a compartment of the ecosystem with functioning microflora, the microbial aerobic degradation in the soil was determined in two laboratory studies. A maximum mineralization of 1.6 % AR was detected as a function of the previous contaminations of the soil and the soil type. Moreover, rapid volatilization of the MTBE from the surface took place perceptibly reducing the bioavailability . The results obtained were readily applicable to the transport studies

USING AN INDEX OF PRECOMPUTED JOINS IN ORDER TO SPEED UP SPARQL PROCESSING

Abstract: SparQL is a query language developed by the W3C, the purpose of which is to query a data set in RDF representing a directed graph. Many free available or commercial products already support SparQL processing. Current index-based optimizations integrated in these products typically construct indices on the subject, predicate and object of an RDF triple, which is a single datum of the RDF data, in order to speed up the execution time of SparQL queries. In order to query the directed graph of RDF data, SparQL queries typically contain many joins over a set of triples. We propose to construct and use an index of precomputed joins, where we take advantage of the homogenous structure of RDF data. Furthermore, we present experimental results, which demonstrate the achievable speed-up factors for SparQL processing.