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The effects of 3, 15, and 27 months of treatment with nitrendipine (10 to 40 mg/day) and enalapril (5 to 20 mg/day) on diastolic blood pressure (DBP), overnight urinary albumin excretion (UAE) rate, glomerular filtration rate (GFR), and renal plasma flow (RPF) were studied prospectively in a parallel group design in 13 microalbuminuric non-insulin dependent diabetic patients with mild hypertension and biopsy-proven diabetic glomerulopathy. Throughout the study period DBP decreased in both groups to95 mm Hg. At three months UAE, GFR, and RPF did not change significantly. At 15 and 27 months UAE (microgram/min, geometric mean and 95% C.I.) decreased respectively from 47.4 (23.4 to 95.9) to 28.6 (10.3 to 79.4), and to 22.3 (10.9 to 45.2; P = 0.0005) with nitrendipine, and from 58.3 (30.3 to 110.9) to 44.1 (22.9 to 84.8), and to 14.7 (4.4 to 49.3; P = 0.0025) with enalapril. Four patients in each group were normoalbuminuric at 27 months and none became macroalbuminuric. At 15 months the GFR (ml/min/1.73 m2, mean +/- SD) increased from 69.5 +/- 15.2 to 96.6 +/- 22.0 (P0.05) with nitrendipine and from 58.9 +/- 10.7 to 78.5 +/- 11.0 (P0.05) with enalapril. At 27 months the GFR was still numerically higher that at baseline either with nitrandipine (81.2 +/- 7.8) and with enalapril (79.9 +/- 17.7) (P = 0.7). The RPF (ml/min/1.73 m2, mean +/- SD) at baseline and at 27 months was comparable either with nitrendipine (456.6 +/- 165.3 vs. 400.9 +/- 112.9) and with enalapril (400.3 +/- 81.3 vs. 399.0 +/- 123.7). Both treatments were well tolerated. This is the first evidence that long-term effective control of arterial blood pressure by a calcium channel blocker or by an angiotensin converting enzyme inhibitor, in addition to reducing albuminuria, also improves GFR in incipient nephropathy.

Uremic patients on long-term hemodialysis show a paradoxical association of hemorrhages on the one hand and thrombotic complications or atherosclerosis on the other. Platelet function has been found to be depressed in some cases but enhanced in others. In 19 patients, both platelet aggregation and prostaglandin formation appeared to be significantly enhanced in response to low concentrations of arachidonic acid but significantly reduced with high concentrations. It is suggested that this double functional abnormality of uremic platelets may contribute to the complex vascular disturbances of hemodialyzed patients.

To determine the possible role of vascular factors in the bleeding tendency of uraemic patients, three major factors of the haemostatic system normally present in vascular tissues were studied. Factor VIII-related protein (F VIII) was detected on the vascular intima of 13 patients and 10 normal subjects. Comparable values of plasminogen activator (PA) were found in tissue slices from 7 patients and 7 controls. In contrast, prostacyclin like (PGI2) activity, measured as platelet aggregation inhibitory potency, was significantly higher in specimens from 15 patients with either acute or chronic uraemia than in 10 controls. The latter abnormality, leading to impaired platelet-vessel wall interaction, might contribute to the disturbed haemostasis of uraemic patients.

Specimens of venous tissues from a group of 25 patients with chronic uremia and 7 patients with acute renal failure generated significantly higher PGI2-like (platelet aggregation inhibiting) activity than venous tissues from 30 normal subjects. After repeated washings, when this activity could barely be detected in the controls, pronounced inhibitory activity was still evident in samples containing venous tissues from uremic patients. Both prolonged bleeding times and increased PGI2-like activity returned to normal in 4 acute uremic patients on restoration of their renal function. These findings may be relevant to the pathogenesis of bleeding in renal failure.

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.