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To assess whether angiotensin-converting enzyme inhibitors and third-generation dihydropyridine calcium channel blockers ameliorate diabetic complications, we compared glomerular filtration rate (GFR; primary outcome), cardiovascular events, retinopathy, and neuropathy in 380 hypertensive type 2 diabetics with albuminuria 2 (IQR: 0.16–0.50 mL/min per 1.73 m 2 ) on combined therapy, 0.36 mL/min per 1.73 m 2 (IQR: 0.18–0.53 mL/min per 1.73 m 2 ) on delapril, and 0.30 mL/min per 1.73 m 2 (IQR: 0.12–0.50 mL/min per 1.73 m 2 ) on placebo ( P =0.87 and P =0.53 versus combined therapy or delapril, respectively). Similar findings were observed when baseline GFR values were not considered for slope analyses. Albuminuria was stable in the 3 treatment groups. The hazard ratio (95% CI) for major cardiovascular events between combined therapy and placebo was 0.17 (0.04–0.78; P =0.023). Among 192 subjects without retinopathy at inclusion, the hazard ratio for developing retinopathy between combined therapy and placebo was 0.27 (0.07–0.99; P =0.048). Among 200 subjects with centralized neurological evaluation, the odds ratios for peripheral neuropathy at 3 years between combined therapy or delapril and placebo were 0.45 (0.24–0.87; P =0.017) and 0.52 (0.27–0.99; P =0.048), respectively. Glucose disposal rate decreased from 5.8±2.4 to 5.3±1.9 mg/kg per min on placebo ( P =0.03) but did not change on combined or delapril therapy. Treatment was well tolerated. In hypertensive type 2 diabetic patients, combined manidipine and delapril therapy failed to slow GFR decline but safely ameliorated cardiovascular disease, retinopathy, and neuropathy and stabilized insulin sensitivity.

We report on some recent advancements on the development of the ROADRUNNER system, which is able to automatically infer a wrapper for HTML pages. One of the major drawbacks of the ROADRUNNER approach was its limited ability in handling irregularities in the source pages. To overcome this issue, we have developed a technique to deal with chunks of unstructured HTML code. Several experiments have been conducted to evaluate the effectiveness of the approach, producing encouraging results. Copyright c 2004, American Association for Artificial Intelligence (www.aaai.org). All rights reserved.

Effects of different membranes and dialysis technologies on patient treatment tolerance and nutritional parameters. There is increasing evidence that the biochemical and cellular phenomena induced by blood/membrane/dialysate interactions contribute to dialysis-related intradialytic and long-term complications. However, there is a lack of large, prospective, randomized trials comparing biocompatible and bioincompatible membranes, and convective and diffusive treatment modalities. The primary aim of this prospective, randomized trial was to evaluate whether the use of polysulfone membrane with bicarbonate dialysate offers any advantages (in terms of treatment tolerance, nutritional parameters and pre-treatment β 2 -microglobulin levels) over a traditional membrane (Cuprophan®). A secondary aim was to assess whether the use of more sophisticated methods consisting of a biocompatible synthetic membrane with different hydraulic permeability at different ultrafiltration rate (highflux hemodialysis and hemodiafiltration) offers any further advantages. Seventy-one Centers were involved and stratified according to the availability of only the first two or all four of the following techniques: Cuprophan® hemodialysis (Cu-HD), low-flux polysulfone hemodialysis (LfPS-HD), high-flux polysulfone high-flux hemodialysis (HfPS-HD), and high-flux polysulfone hemodiafiltration (HfPS-HDF). The 380 eligible patients were randomized to one of the two or four treatments (132 to Cu-HD, 147 to LfPS-HD, 51 to HfPS-HD and 50 to HfPS-HDF). The follow-up was 24 months. No statistical difference was observed in the algebraic sum of the end points between bicarbonate dialysis with Cuprophan® or with low-flux polysulfone, or among the four dialysis methods under evaluation. There was a significant decrease in pre-dialysis plasma β 2 -microglobulin levels in high-flux dialysis of 9.04 ± 10.46 mg/liter (23%) and in hemodiafiltration of 6.35 ± 12.28 mg/liter (16%), both using high-flux polysulfone membrane in comparison with Cuprophan® and low-flux polysulfone membranes (P = 0.032). The significant decrease in pre-dialysis plasma β 2 -microglobulin levels could have a clinical impact when one considers that β 2 -microglobulin accumulation and amyloidosis are important long-term dialysis-related complications.

The authors consider structured Web sites, those sites in which structures are so tight and regular that one can assimilate the site, from the logical viewpoint, to a conventional database. They have argued that, with respect to structured Web servers, it is possible to apply ideas from traditional database techniques, specifically with respect to design, query, and update. They focus on the querying process, which consists of associating a scheme with a server and then using this scheme to pose queries in a high level query language. To describe the scheme, they use a specific data model, called the ARANEUS Data Model (ADM). They call ADM a page oriented model, in the sense that the main construct of the model is that of a page scheme, used to describe the structure of sets of homogeneous pages in the server. ADM schemes are then offered to the user, who can query them using the ULIXES language, whose expressions produce relations as results. These are essentially relational views over Web data and can therefore be queried using any relational query language. It should be noted that the approach inherited some ideas from other proposals for query languages for the Web. However, these approaches are mainly based on a loose notion of structure, and tend to view the Web as a huge collection of unstructured objects, organized as a graph. In contrast, the approach explicitly considers structure, both in the information source (the Web) and in the derived information (the relational views).

Network connectivity is a basic notion for big data analysis, with many practical applications. In particular, the analysis of the largest strongly connected component is at the heart of the famous bow-tie structure of the Web. In this paper, we go beyond connected components and characterize the properties of the higher-connectivity components that lie inside real-world networks. We combine and extend recently developed techniques for scaling up to real-world datasets with up to 23.1 billion edges. Our experiments point out a striking difference between structural properties in social and web graphs, and highlight deep properties of social networks which may be helpful in devising theoretical models that can better capture their structure.

The recent literature has provided a solid theoretical foundation for the use of schema mappings in data-exchange applications. Following this formalization, new algorithms have been developed to generate optimal solutions for mapping scenarios in a highly scalable way, by relying on SQL. However, these algorithms suffer from a serious drawback: they are not able to handle key constraints and functional dependencies on the target, i.e., equality generating dependencies (egds). While egds play a crucial role in the generation of optimal solutions, handling them with first-order languages is a difficult problem. In fact, we start from a negative result: it is not always possible to compute solutions for scenarios with egds using an SQL script. Then, we identify many practical cases in which this is possible, and develop a best-effort algorithm to do this. Experimental results show that our algorithm produces solutions of better quality with respect to those produced by previous algorithms, and scales nicely to large databases.

We introduce the +Spicy mapping system. The system is based on a number of novel algorithms that contribute to increase the quality and expressiveness of mappings. +Spicy integrates the computation of core solutions in the mapping generation process in a highly efficient way, based on a natural rewriting of the given mappings. This allows for an efficient implementation of core computations using common runtime languages like SQL or XQuery and guarantees very good performances, orders of magnitude better than those of previous algorithms. The rewriting algorithm can be applied both to mappings generated by the system, or to pre-defined mappings provided as part of the input. To do this, the system was enriched with a set of expressive primitives, so that +Spicy is the first mapping system that brings together a sophisticate and expressive mapping generation algorithm with an efficient strategy to compute core solutions.

Research has investigated mappings among data sources under two perspectives. On one side, there are studies of practical tools for schema mapping generation; these focus on algorithms to generate mappings based on visual specifications provided by users. On the other side, we have theoretical researches about data exchange. These study how to generate a solution - i.e., a target instance - given a set of mappings usually specified as tuple generating dependencies. However, despite the fact that the notion of a core of a data exchange solution has been formally identified as an optimal solution, there are yet no mapping systems that support core computations. In this paper we introduce several new algorithms that contribute to bridge the gap between the practice of mapping generation and the theory of data exchange. We show how, given a mapping scenario, it is possible to generate an executable script that computes core solutions for the corresponding data exchange problem. The algorithms have been implemented and tested using common runtime engines to show that they guarantee very good performances, orders of magnitudes better than those of known algorithms that compute the core as a post-processing step.

Data-intensive Web sites are large sites based on a back-end database, with a fairly complex hypertext structure. The paper develops two main contributions: (a) a specific design methodology for data-intensive Web sites, composed of a set of steps and design transformations that lead from a conceptual specification of the domain of interest to the actual implementation of the site; (b) a tool called H omer , conceived to support the site design and implementation process, by allowing the designer to move through the various steps of the methodology, and to automate the generation of the code needed to implement the actual site.Our approach to site design is based on a clear separation between several design activities, namely database design, hypertext design, and presentation design. All these activities are carried on by using high-level models, all subsumed by an extension of the nested relational model; the mappings between the models can be nicely expressed using an extended relational algebra for nested structures. Based on the design artifacts produced during the design process, and on their representation in the algebraic framework, H omer is able to generate all the code needed for the actual generation of the site, in a completely automatic way.

The paper considers the Araneus data model which employs database techniques and wrappers to extract data from and generate Web sites. The project features a logical model that abstracts physical aspects of Web sites. Araneus provides high-level descriptions of pages that let us both extract data from the Web and generate Web sites from databases.

We propose new criteria for the classification of systems for database cooperation, based on the nature of the component databases. In fact, the traditional criteria - heterogeneity, distribution, and autonomy - are often constraints for the design process, rather than design parameters. In this case, other features of the component databases should be addressed. We claim that a more useful classification can be based on three new criteria: (a) degree of transparency, (b) complexity of operations, and (c) level of liveliness of data. This leads us to distinguish three main categories of systems: (i) multidatabases, (ii) data warehouses, and (iii) local information systems with external data. For each of these categories, we discuss implementations based on tools offered by currently available technology

The IsaLog¬ model and language are presented. The model has complex objects with classes, relations, and isa hierarchies. The language is strongly typed and declarative. The main issue is the definition of the semantics of the IsaLog language. The novel features are mostly due to the interaction of hierarchies with negation in the body of rules. Two semantics are presented and shown to be equivalent: a stratified semantics based on an original notion of stratification, needed in order to correctly deal with hierarchies, and a reduction to logic programming with function symbols. The solutions are based on a new technique (explicit Skolem functors) that provides a powerful tool for manipulating object identifiers.

The paper develops Editor, a language for manipulating semistructured documents, such as those typically available on the Web. Editor programs are based on two simple ideas, taken from text editors: “search” instructions are used to select regions of interest in a document, and “cut & paste” instructions to restructure them. We study the expressive power and the complexity of these programs. We show that they are computationally complete, in the sense that any computable document restructuring can be expressed in Editor. We also study the complexity of a safe subclass of programs, showing that it captures exactly the class of polynomial-time restructurings. The language has been implemented in Java and is currently used in the Araneus project as a basis for a wrapper-generation toolkit.

The IsaLog model and language are presented. The model has complex objects with classes, relations, and is a hierarchies. The language is strongly types and declarative. The main issue is the definition of the semantics of the language, given in three different ways that are shown to be equivalent: a model-theoretic semantics, a reduction to logic programming with function symbols, and a fixpoint semantics. Each of the semantics presents new aspects with respect to existing proposals because of the interaction of oid-invention with general is a hierarchies. The solutions are based on the explicit Skolem functors, which provide a powerful tool for manipulating object-identifiers. >

A methodology for designing and maintaining large Web sites is introduced. It would be especially useful if data to be published in the site are managed using a DBMS. The design process is composed of two intertwined activities: database design and hypertext design. Each of these is further divided in a conceptual phase and a logical phase, based on specific data models, proposed in our project. The methodology strongly supports site maintenance: in fact, the various models provide a concise description of the site structure; they allow to reason about the overall organization of pages in the site and possibly to restructure it.

In its infancy, the World-Wide Web consisted of a web of largely static hypertext documents. As time progresses it is evolving into a domain which supports almost arbitrary networked computations. Central to its successful operation is the agreement of the HTML and http standards, which provide inter-node communication via the medium of streamed files. Our hypothesis is that, as application sophistication increases, this file-based interface will present the same limitations to programmers as the use of traditional file and database system interfaces within programming languages. Persistent programming systems were designed to overcome these problems in traditional domains; our investigation is to reapply the resulting research to the new domain of the Web. The result of this should be the ability to pass typed data layered on top of the existing standards, in a manner that is fully integrated with them. A typed object protocol integrated with existing standards would allow the Web to be used to host a global persistent address space, thus making it a potential data repository for a generation of database programming languages.