Search

In order to assess the potential influence of the costal environment on marine aerosol chemical composition, two parallel aerosol data sets, collected during two campaigns (coastal site campaign at Mace Head station and open ocean campaign in North Atlantic Ocean), are compared. Aerosol samples were analyzed for Water Soluble Organic Carbon (WSOC), Total Carbon (TC), and main inorganic ions. In addition, a detailed chemical characterization of WSOC was performed. Results show a strong similarity between size-segregated chemical composition in the submicron size interval, at the coastal station and open ocean site, thus excluding potential effects of the shore line environment. Only the coarse fraction seems in some way influenced by the proximity of the shoreline, the sea salt concentration being higher in this size interval for the coastal site. Keywords Aerosol chemistry, biogenic particles, coastal particles, marine aerosols [ABSTRACT FROM AUTHOR]

The necessity of a navigation system, more flexible and interoperable, has become more and more important and the use of satellite system has been recognized as the main means to obtain this improvement. In the aeronautical field the GNSS has been chosen by the ICAO as fundamental component for the future CNS/ATM systems because of its peculiar characteristics that provide the necessary assistance during all flight phases. The ATC interface developed in the frame of EtoG aims to facilitate the introduction of GNSS services in Italian airspaces. The EtoG programme is a programme for researching and developing of new aeronautic applications to optimize the existing procedures and to find new technologies for the management of critical situations (safety) by using satellite navigation. The introduction of satellite navigation (GPS-EGNOS-GALILEO) allows the management of the aircraft flying phases with remarkable advantage compared to the traditional systems. [ABSTRACT FROM AUTHOR]

This paper reviews recent developments in modelling the two main sets of bank-erosion processes and mechanisms, namely fluvial erosion and mass failure, before suggesting an avenue for research to make further progress in the future. Our review of mass failure mechanisms reveals that the traditional use of limit equilibrium methods to analyse bank stability has in recent years been supplemented by research that has made progress in understanding and modelling the role of positive and negative pore water pressures, confining river pressures, and hydrograph characteristics. While understanding of both fluvial erosion and mass failure processes has improved in recent years, we identify a key limitation in that few studies have examined the nature of the interaction between these processes. We argue that such interactions are likely to be important in gravel-bed rivers and present new simulations in which fluvial erosion, pore water pressure, and limit equilibrium stability models are combined into a fully coupled analysis. The results suggest that existing conceptual models, which describe how bank materials are delivered to the fluvial sediment transfer system, may need to be revised to account for the unforeseen effects introduced by feedback between the interacting processes. [ABSTRACT FROM AUTHOR]

Ventilator-associated pneumonia (VAP) is defined as an infection of the lung parenchyma developing during mechanical ventilation, usually after at least 2 days of positive-pressure ventilation delivered via an endotracheal tube [1, 2]. This time criterion aims to exclude pneumonias caused by infectious agents already present or incubating before mechanical ventilation is started [1]. The diagnosis of VAP is usually based on clinical, radiographic, and microbiological criteria. However, the accuracy of data on the epidemiology of VAP is limited by the lack of a gold standard for its diagnosis [3]. In most reports the incidence of VAP ranges from 8% to 28% [3]. The lower incidence is reported in studies where quantitative cultures of protected specimen brushes were used to define pneumonia [4]. The incidence seems to rise from 5% for patients receiving mechanical ventilation for 1 day to 69% for those receiving mechanical ventilation for more than 30 days, with an incremental risk of pneumonia of around 1% per day [2, 5, 6]. Some authors report that, although the cumulative risk of developing VAP increases over time, the daily hazard rate decreases after 5 days of mechanical ventilation; these authors estimate the risk per day at 3% for the first 5 days of mechanical ventilation, 2% between days 5 and 10 of mechanical ventilation and 1% between days 10 and 15 of mechanical ventilation [7]. VAP is, then, a common complication of long ICU stays. Among the causative pathogens of VAP, Gram-positive strains are common and are associated with a high mortality. [ABSTRACT FROM AUTHOR]

Fecal incontinence is a multifactorial disease. Anorectal physiology studies play an outstanding role in the evaluation of its etiology and severity, the two main factors that constitute the basis for the correct choice of treatment. However, the prognostic role of clinical factors and anorectal physiological tests in predicting the outcome to either conservative or surgical treatment is questionable. [ABSTRACT FROM AUTHOR]

In this paper we present a method for finding exact solutions of the Max-Cut problem max xTLx such that x ∈ { − 1,1}n. We use a semidefinite relaxation combined with triangle inequalities, which we solve with the bundle method. This approach is due to [12] and uses Lagrangian duality to get upper bounds with reasonable computational effort. The expensive part of our bounding procedure is solving the basic semidefinite programming relaxation of the Max-Cut problem. We review other solution approaches and compare the numerical results with our method. We also extend our experiments to unconstrained quadratic 0-1 problems and to instances of the graph bisection problem. The experiments show, that our method nearly always outperforms all other approaches. Our algorithm, which is publicly accessible through the Internet, can solve virtually any instance with about 100 variables in a routine way. [ABSTRACT FROM AUTHOR]

The heads of big diameter, like Mc Farrar, Ring and Muller, already appeared during the 60's. At that time characterized by a metal — metal coupling, whose sizing generally spared heads from 32mm to 41mm, all the correlated hip joint reconstructions reported quite variable clinical outcomes. [ABSTRACT FROM AUTHOR]

Our main purpose is to characterize the class of L-convex polyominoes introduced in [3] by means of their horizontal and vertical projections. The achieved results allow an answer to one of the most relevant questions in tomography i.e. the uniqueness of discrete sets, with respect to their horizontal and vertical projections. In this paper, by giving a characterization of L-convex polyominoes, we investigate the connection between uniqueness property and unimodality of vectors of horizontal and vertical projections. In the last section we consider the continuum environment; we extend the definition of L-convex set, and we obtain some results analogous to those for the discrete case. [ABSTRACT FROM AUTHOR]

In this paper we present a novel instance pruning technique for Information Extraction (IE). In particular, our technique filters out uninformative words from texts on the basis of the assumption that very frequent words in the language do not provide any specific information about the text in which they appear, therefore their expectation of being (part of) relevant entities is very low. The experiments on two benchmark datasets show that the computation time can be significantly reduced without any significant decrease in the prediction accuracy. We also report an improvement in accuracy for one task. [ABSTRACT FROM AUTHOR]

Information retrieval is moving beyond the stage where users simply type one or more keywords and retrieve a ranked list of documents. In such a scenario users have to go through the returned documents in order to find what they are actually looking for. More often they would like to get targeted answers to their queries without extraneous information, even if their requirements are not well specified. In this paper we propose an approach for designing a web retrieval system able to find the desired information through several interactions with the users. The proposed approach allows to overcome the problems deriving from ambiguous or too vague queries, using semantic search and topic detection techniques. The results of the very first experiments on a prototype system are also reported. [ABSTRACT FROM AUTHOR]

An association between sex steroids and mammographic density (MD), a predictor of breast cancer (BC) risk, is supported by findings of increased densities after hormone therapy and reduced densities after tamoxifen treatment. Herein, ethnic differences in urinary hormone levels and their relation to MDs were investigated. Because 2-hydroxyestrone (2-OH-E1) is considered less carcinogenic than 16α-hydroxyestrone(16α-OH-E1), we hypothesized an inverse relation between the 2-OH-E1/16α-OH-E1 (2/16) ratio and breast densities. Women recruited completed a questionnaire and donated urine during the luteal phase. Urinary estrone (E1), estradiol (E2), testosterone (T), and 5α-androstane-3α, 17β-diol (ADIOL) were measured by indirect radioimmunoassay (RIA) and 16α- and 2-OH-E1 by competitive immunoassays. MDs were assessed with a computer-assisted method and applied multiple linear regressions. The total number of subjects was 305 (35-75 years, $$ \bar X $$ = 47.2 years). Their ethnic distribution was Caucasian (110), Japanese (86), Hawaiian (35), Chinese (28), and mixed/other ethnicity (46). The data indicate that the body mass index (BMI), 2-OH-E1, androgens (A), total hormones, and the 2/16 ratio were significantly lower in Asians than in Caucasians, but the % MDs were 22% higher in Asians. None of the individual hormones was associated with MDs. However, contrary to the initial hypothesis, the 2/16 ratio was directly related to MDs. The ratio was 25% lower in the lowest MD category as compared to the highest category. The data suggest that the effects of endogenous hormones on BC risk may not be mediated through MDs in adult women. [ABSTRACT FROM AUTHOR]

ECO is a method for the enumeration of classes of combinatorial objects based on recursive constructions of such classes. In this paper we use the ECO method and the concept of succession rule to develop an algorithm for the exhaustive generation of convex polyominoes. Then we prove that this algorithm runs in constant amortized time. [ABSTRACT FROM AUTHOR]

A class of production-distribution problems with unknown-but-bounded uncertain demand is considered. At each time, the demand is unknown but each of its components is assumed to belong to an assigned interval. Furthermore, the system has production and transportation capacity constraints. We face the problem of finding a control strategy that keeps the storage levels bounded. We also deal with the case in which storage level bounds are assigned and the controller must keep the state within these bounds. Both discrete and continuous time models are considered. We provide basic necessary and sufficient conditions for the existence of such strategies. We propose several possible feedback control laws which are robust with respect to link failures and/or network parameter variations. We finally consider the case of processing/transportation delays. [ABSTRACT FROM AUTHOR]

Serum-free growth of recombinant mammalian cells in suspension offers several advantages over adherent cultivation in fetal calf serum containing medium. We report here the development of a serum-free medium for HEK.EBNA cells supporting growth in suspension as single cells or small aggregates, thus facilitating the scale-up of the culture to large scale. In addition, we describe a suitable transfection protocol for these suspension-adapted cells. When applied in combination, the HEK.EBNA/oriP expression system becomes highly efficient, giving rise to production of 50-100 mg of recombinant protein within approx. 3 months. [ABSTRACT FROM AUTHOR]

Motivated by a typical and well-known problem of neurobiological modeling, a parallel algorithm devised to simulate sample paths of stationary normal processes with rational spectral densities is implemented to evaluate first passage time probability densities for time-varying boundaries. After a self-contained outline of the original problem and of the involved computational framework, the results of numerous simulations are discussed and conclusions are drawn on the effect of a periodic boundary and a Butterworth-type covariance on determining quantitative and qualitative features of first passage time probability densities. [ABSTRACT FROM AUTHOR]

In the framework of the QUEST-EC project, an intensive measurement campaign was carried out in early spring 2004 at San Pietro Capofiume, a rural site located in the Po Valley. The aim was to investigate the mechanisms of new particle formation in a polluted environment, and to assess the role of aerosol chemical composition in the formation and growth of aerosol particles. The results confirm that new particle formation was preferentially associated with relatively clean air masses, and evidence that new particle formation in this polluted environment is due to a synergy between particular meteorological conditions and the physicochemical characteristics of aerosol particles. Keywords New particle formation, nucleation, aerosol chemistry [ABSTRACT FROM AUTHOR]