Six years' (1992–1997) evolution of phytoplankton communities after recovery by liming in Lake Orta, northern Italy

Lake Orta became heavily polluted in 1926 by ammonium sulphate and copper. After a couple of years the biological communities became extremely simplified and were composed of a few resistant species. This acute copper pollution was followed by a chronic acidification of the water, brought about by in‐lake biochemical oxidation of ammonium. Since the 1960s, heavy metals discharged from some plating factories became an additional source of pollution. After the reduction of ammonium discharge in 1982 and from May 1989 to June 1990 the lake was limed: the pH at overturn increased from pH 4.4 to 5.9, the metals’ concentration decreased and the number of planktonic taxa rapidly increased. The present paper deals with the recent (1992–1997) evolution of the phytoplankton communities analysed by sample clustering: the cluster analysis indicates the separation of two large groups of samples (1992–1993 and 1995–1997). Such clustering is because of the gradual decline of the chlorophytes (for a long period the most important group in Lake Orta) between 1992 and 1994, followed by their marked decrease between 1995 and 1997, during which they were replaced by blue–green algae. Also noticeable was the increase in diatoms, which had disappeared from the phytoplankton community from the 1930s until 1994, but during spring and summer 1997 they amounted to 40% of community abundance. Although it is now possible to describe a phytoplanktonic seasonal succession in Lake Orta, the dissimilarities shown by the cluster analysis seem to indicate the existence of a certain year‐to‐year variability inside the dominant species assemblage, meaning that the phytoplankton community is still evolving. In spite of the phytoplankton’s fast recovery after liming, it is only since 1994 that the algal community started to change toward a phytoplankton assemblage more typical of deep subalpine lakes.     

Linear models for 1-group two-dimensional guillotine cutting problems

In this study we present integer linear and non-linear models to generate 1-group constrained and unconstrained two-dimensional guillotine cutting patterns, including exact and non-exact cases. These patterns appear in different cutting processes as, for example, in the furniture industry. The models are useful for research and development of more effective solution methods, exploring particular structures, model decomposition, model relaxations, etc. They are also helpful for the performance evaluation of heuristic methods, since they allow (at least for problems of moderate size) an estimation of the optimality gap of heuristic solutions. To demonstrate the effectiveness of the proposed models, we compare them with models of the literature by solving a number of examples randomly generated and an actual example derived from a furniture company. Such results were produced using a well-known commercial software (the modelling language GAMS and the solver CPLEX) and they show that the computational efforts required to solve the models can be very different.     

Pulmonary venous flow velocity patterns in 143 normal subjects aged 20 to 80 years old. An echo 2D colour Doppler cooperative study

In order to find out the normal values and to evaluate the effects of age, heart rate, sex, and haemodynamic and standard echocardiographic parameters on pulmonary venous flow velocity obtained by the transthoracic approach. Doppler pulmonary venous flow parameters were measured in 143 healthy subjects aged from 20 to 80 years. Doppler pulmonary venous flow parameters which had the best correlation with age were: the peak velocity of the systolic wave (r = 0.39) and its integral (r = 0.5), the peak velocity of the diastolic wave (r = -0.6) and its integral (r = -0.44); the systolic (r = 0.68) and diastolic fractions (r = -0.68); the systolic/diastolic peak velocity ratio (r = 0.73) and the systolic/diastolic integral ratio (r = 0.7). The atrial reversal wave did not correlate with age; the atrial reversal wave was more difficult and probably less reliable to measure than the systolic and diastolic waves. The correlations of pulmonary venous flow parameters with mitral flow parameters were also examined. This study showed that, in healthy subjects, despite an increase in the early and atrial waves from the annulus to the tips of the mitral leaflets, there is a similar association between pulmonary venous flow and mitral flow measured at the annulus or at the tips of the mitral leaflets. The intra-observer reproducibility of all the pulmonary venous flow parameters considered were found to be excellent. Moderate inter-observer variability was observed for the systolic, diastolic and atrial reversal wave peak velocities and integrals; however, the systolic/diastolic ratio improved the precision of the measurements. Multivariate analysis showed that age is the principal determinant of the Doppler parameters of pulmonary venous flow: heart rate, sex, body surface area, the size of the left atrium in systole and the left ventricular ejection fraction all influence the Doppler parameters of pulmonary venous flow, even if only slightly.     

High-dose etoposide enables the collection of peripheral blood stem cells in patients who failed cyclophosphamide-induced mobilization

A case of an intracranial cavernous angioma, which presented with headaches and seizures in a pregnant patient, is described. Diagnosis was established with magnetic resonance imaging. A computer-assisted literature search uncovered no previously reported case of intracranial cavernous angioma initially presenting during pregnancy.     

A Tabu search algorithm for solving the extended maximal availability location problem

The aim of this study is to develop a Tabu Search (TS) procedure for the Extended Maximal Availability Location Problem (EMALP). This probabilistic location problem consists of locating the servers of the system so that the expected coverage of demand is maximized, in which a demand area is said to be covered if there is at least one server available within a given critical distance with a probability greater than or equal to a given reliability. The results obtained from this procedure are compared with those obtained from the Simulated Annealing (SA) procedure developed by Galvão et al. for the same problem. To the best of our knowledge, we are not aware of other methods proposed in the literature to solve the EMALP. The computational results show that in terms of the quality of the solutions, SA slightly outperforms TS for the smaller networks, while TS outperforms SA for the larger networks.     

On solving three-dimensional open-dimension rectangular packing problems

In this article, a recently proposed three-dimensional open-dimension rectangular packing problem is considered, in which the objective is to find a minimal volume rectangular container that packs a set of rectangular boxes. The literature has tackled small-sized instances of this problem by means of optimization solvers, position-free mixed-integer programming (MIP) formulations and piecewise linearization approaches. In this study, the problem is alternatively addressed by means of grid-based position MIP formulations, whereas still considering optimization solvers and the same piecewise linearization techniques. A comparison of the computational performance of both models is then presented, when tested with benchmark problem instances and with new instances, and it is shown that the grid-based position MIP formulation can be competitive, depending on the characteristics of the instances. The grid-based position MIP formulation is also embedded with real-world practical constraints, such as cargo stability, and results are additionally presented.     

RBFNN-based hole identification system in conducting plates

A neural-based signal processing system that exploits radial basis function neural network (RBFNN) is proposed to solve the problem of detecting and locating circular holes in conducting plates by means of nondestructive eddy currents testing. The capabilities of basic multilayer perceptron and radial basis function (RBF) schemes are first investigated. Since the achieved performance revealed insufficient, a two-step procedure is then analyzed: in the first step, an RBFNN is used to estimate the distances between the hole's center and the eddy current magnetic sensors; a least square algorithm is then exploited in order to locate the hole starting from the previously estimated distances. The performance of the proposed system are tested on a database of simulated experiments based on the a priori knowledge of the corresponding boundary value direct problem solution, by taking advantage of the closed-form analytical expression of the solution in order to generate a wide range of possible sensor-hole configurations. Both noiseless and noisy measurements are taken into account for assessing the system robustness. The main result achieved is discussed.     

From content delivery today to information centric networking

Today, content delivery is a heterogeneous ecosystem composed by various independent infrastructures. The ever increasing growth of Internet traffic has encouraged the proliferation of different architectures to serve content provider needs and user demand. Despite the differences among the technology, their low level implementation can be characterized in a few fundamental building blocks: network storage, request routing, and data transfer. Existing solutions are inefficient because they try to build an information centric service model over a network infrastructure which was designed to support host-to-host communications. The Information-Centric Networking (ICN) paradigm has been proposed as a possible solution to this mismatch. ICN integrates content delivery as a native network feature. The rationale is to architect a network that automatically interprets, processes, and delivers content (information) independently of its location. This paper makes the following contributions: (1) it identifies a set of building blocks for content delivery, (2) it surveys the most popular approaches to realize the above building blocks, (3) it compares content delivery solutions relying on the current Internet infrastructure with novel ICN approaches.     

Consistent loss of functional transforming growth factor beta receptor expression in murine plasmacytomas

SPR Online (http:@www.pedrad.org) is a recently developed digital representation of the Society for Pediatric Radiology (SPR) that enables physicians to access pertinent information and services on the Internet. SPR Online was organized on the basis of the five main services of the SPR, which include Administration, Patient Care, Education, Research, and Meetings. For each service, related content from the SPR was digitized and placed onto SPR Online. Usage over a 12-month period was evaluated with server log file analysis. A total of 3,209 users accessed SPR Online, viewing 11,246 pages of information. A wide variety of information was accessed, with that from the Education, Administration, and Meetings services being the most popular. Fifteen percent of users came from foreign countries. As a virtual professional society, SPR Online greatly enhances the power and scope of the SPR and has proved to be a popular resource, meeting the diverse information needs of an international community of pediatric radiologists.     

Automatic evaluation of form errors in high-density acquired surfaces

In this paper the authors present an original methodology aiming at the automation of the geometric inspection, starting from a high-density acquired surface. The concept of intrinsic nominal reference is herein introduced in order to evaluate geometric errors. Starting from these concepts, a new specification language, which is based on recognisable geometric entities, is defined. This work also proposes some surface differential properties, such as the intrinsic nominal references, from which new categories of form errors can be introduced. Well-defined rules are then necessary for the unambiguous identification of these intrinsic nominal references. These rules are an integral part of the tolerance specification. This new approach requires that a recognition process be performed on the acquired model so as to automatically identify the already-mentioned intrinsic nominal references. The assessable errors refer to recognisable geometric entities and their evaluation leaves the nominal reference specification aside since they can be intrinsically associated with a recognised geometric shape. Tolerance specification is defined based on the error categories which can be automatically evaluated and which are an integral part of the specification language.