1,721,056 research outputs found
Structural and ultrastructural aspects of growth in Oscarella lobularis (Porifera, Demospongiae)
No full textContribution to the study of egg development and derivation in Oscarella lobularis (Porifera, Demospongiae)
No full textA new approach for modeling dry deposition velocity of particles
Full text linkThe dry deposition process is recognized as an important pathway among the various removal processes of pollutants in the atmosphere. In this field, there are several models reported in the literature useful to predict the dry deposition velocity of particles of different diameters but many of them are not capable of representing dry deposition phenomena for several categories of pollutants and deposition surfaces. Moreover, their applications is valid for specific conditions and if the data in that application meet all of the assumptions required of the data used to define the model. In this paper a new dry deposition velocity model based on an electrical analogy schema is proposed to overcome the above issues. The dry deposition velocity is evaluated by assuming that the resistances that affect the particle flux in the Quasi-Laminar Sub-layers can be combined to take into account local features of the mutual influence of inertial impact processes and the turbulent one. Comparisons with the experimental data from literature indicate that the proposed model allows to capture with good agreement the main dry deposition phenomena for the examined environmental conditions and deposition surfaces to be determined. The proposed approach could be easily implemented within atmospheric dispersion modeling codes and efficiently addressing different deposition surfaces for several particle pollution
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Long-term urologic outcome in patients with caudal regression syndrome, compared with meningomyelocele and spinal cord lipoma
No full textBackground/Purpose: The long-term urologic outcome in a large series of patients with neural tube defects was evaluated. Methods: The following clinical parameters in 398 patients ranging from 1 to 37 years of age-69 with caudal regression syndrome (CRS), 244 with meningomyelocele (MMC), and 85 with spinal lipoma (SL)-were studied: congenital renal anomalies, renal function, vesico-ureteric reflux, upper tract dilatation, urodynamic pattern, and urinary continence. Results: Single kidney was much more frequent in CRS (20.3%), compared with MMC (1.2%) and SL (0%). Vesico-ureteric reflux was found in 37.7% of patients with CRS, 43.0% of MMC, and 21.2% of SL. Patients with CRS had a higher risk of impaired renal function (8.7%), compared with MMC (5.3%) and SL (1.2%). Neuropathic bladder was found in 61% of patients with CRS, 98% of MMC, and 42% of SL. Among them, clean intermittent catheterization and drugs allowed 30% of patients with CRS, 45% of MMC, and 71% of SL to be dry for more than 4 hours. Conclusions: Diagnosis influences the urologic outcome in neural tube defect. In CRS, the incidence of renal agenesis and vesico-ureteric reflux was unexpectedly high. The risk of renal damage and, in those with neuropathic bladder, of urinary incontinence, was similar to patients with MMC. © 2008 Elsevier Inc. All rights reserved
Ultrastructural study of spermatogenesis in Oscarella lobularis (Porifera, Demospongiae)
No full textUn nuovo approccio per l’integrazione dell’analisi di rischio nella valutazione degli impatti ambientali connessi alle operazioni di smantellamento di un impianto nucleare
No full textLa disattivazione e lo smantellamento delle installazioni nucleari a seguito della loro cessazione di esercizio è uno dei
problemi che molti paesi si trovano ad affrontare avendo come vincolo la garanzia della sostenibilità ambientale e la
sicurezza della popolazione e dei lavoratori coinvolti nelle varie procedure operative. Tuttavia, non esiste allo stato
attuale una metodologia capace di classificare la rilevanza dei vari tipi di impatto, ma piuttosto una varietà di strategie
che dipendono fortemente dalla normativa vigente nel paese di appartenenza. Ciò ha portato a trascurare la definizione
di una procedura capace di individuare proattivamente le condizioni di rischio connesse alle attività di tipo convenzionale
e non, comprese quelle associate al verificarsi di situazioni incidentali. In questo ambito viene proposto un approccio
metodologico, denominato Environmental Impact Mode and Criticality Analysis (EIMCA), che integra l’analisi degli impatti
ambientali con l’analisi del rischio. Tale approccio si propone di individuare ed ampliare lo studio dei possibili scenari
che, durante le varie fasi programmate per lo smantellamento dell’impianto, possono indurre effetti negativi sui fattori
ambientali e, quindi, situazioni pericolose per la salute degli operatori e della popolazione
Attività di interconfronto tra codici di trasporto atmosferico per la preparazione e la risposta alle emergenze nucleari
No full textIn questo lavoro vengono presentati e confrontati i risultati ottenuti con tre differenti
codici (FLEXPART, CALPUFF e ldX) per il trasporto atmosferico di inquinanti radioattivi.
I codici vengono confrontati su una singola simulazione di un possibile rilascio
incidentale alla stazione frontaliera di Gösgen (CH), in condizioni meteorologiche sfavorevoli
per il territorio italiano.In this work we present and compare the results obtained iwth three different codes
(FLEXPART, CALPUFF and ldX) for the atmospheric dispersion of radioactive pollutants.
The codes are compared on a single simulation of a possible incident release in
the Gösgen (CH) nuclear power plant with weather conditions that are not favorable to
the Italian territory
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