305,225 research outputs found
Destino ambientale di glyphosate in agroecosistemi differenti della regione Veneto e il suo impatto sulle acque sotterranee
No full textIl glifosate è uno degli erbicidi più utilizzati a livello mondiale, ad ampio spettro, sistemico e di post-emergenza. In questo contesto, il 90% delle vendite annuali dell’erbicida è utilizzato nel settore agricolo, dove gli agrofarmaci a base di glifosate vengono distribuiti principalmente prima della semina o in post-raccolta (durante il periodo di intercolturale) per il controllo chimico delle infestanti. Le colture trattate con l'erbicida sono sia annuali (cereali e semi oleosi) che perenni (frutteti e vigneti).
In Europa, il glifosate è attualmente approvato fino al 15 dicembre 2022 e la Commissione Europea potrebbe decidere di prolungarne ulteriormente l'uso nei terreni agricoli a causa della decisione di EFSA di rinviare il suo parere scientifico sulla riapprovazione di glifosate. Per questo motivo, studiare le dinamiche di glifosate nel suolo e nell'acqua è ancora necessario per capire il suo ruolo nell'inquinamento delle acque sotterranee. Studi specifici per la prevenzione della contaminazione delle acque di falda sono altamente raccomandati per supportare i decisori politici e i professionisti del settore a identificare le aree di protezione delle acque potabili, che ancora oggi sono, in gran parte, poco definite. L'identificazione di regole univoche risulta essere particolarmente difficile a causa della complessa relazione tra agrofarmaco e agroecosistema, e quindi delle dinamiche di adsorbimento-degradazione-trasporto fortemente sito-specifiche. Ciò dipende anche dalle caratteristiche peculiari di ciascuna molecola (coefficiente di adsorbimento, solubilità, tempo di emivita, ecc.) e dalla variabilità pedo-climatica e gestionale del sito interessato. Ad esempio, nella regione Veneto, particolare attenzione va prestata alle aree di bassa pianura, dove le condizioni di falda superficiale aumentano il rischio di contaminazione delle acque sotterranee nelle aree agricole.
L’intento di questa tesi è quelli di fornire nuovi spunti di riflessione sulla peculiare dinamica nel suolo e nell'acqua di glifosate in condizioni ancora poco studiate. In particolare, gli studi sono stati condotti in due aree della regione Veneto (alta pedemontana e bassa pianura), comprendenti tre diversi agroecosistemi (vigneto, agricoltura convenzionale e conservativa) e sono stati identificati i fattori che influenzano le dinamiche di adsorbimento, dissipazione e trasporto dell'erbicida (Capitoli 2 e 3). I coefficienti di adsorbimento di glifosate sono stati calcolati lungo il profilo di suolo per diversi strati, fino a 70 e 110 cm (Capitoli 2 e 3, rispettivamente). In particolare, è stato ampiamente dimostrato il ruolo chiave
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sull'adsorbimento di Fe e Al chelati alla sostanza organica, suggerendo che un'attenta analisi della composizione minerale (oltre a quella del pH e della tessitura del suolo) risulta necessaria per determinare la vulnerabilità dell'agroecosistema all'inquinamento della falda (Capitoli 2 e 3). Inoltre, la dissipazione di glifosate nel suolo è stata monitorata e modellata (Capitolo 2), così come per AMPA - ancora poco studiato nella letteratura scientifica - con una nuova equazione proposta per prevedere il suo tasso di decadimento. Lo studio del trasporto di glifosate e AMPA ha rivelato una bassa mobilità nei vigneti dell'area pedemontana, nonostante alcuni rapidi movimenti verticali fino allo strato più profondo abbiano suggerito la presenza di movimenti preferenziali dovuti a condizioni di suolo ben strutturato. Anche nella bassa pianura veneta è stato riscontrato un rapido movimento verso la falda freatica. Lo studio modellistico condotto con HYDRUS-1D (Capitolo 4) ha permesso di identificare i fattori che hanno portato alla contaminazione. In questo caso, le condizioni delle acque sotterranee poco profonde hanno influenzato notevolmente il trasporto dei soluti modificando la struttura del suolo e aumentando la frequenza dei macropori.Glyphosate is one of the most used broad-spectrum, systemic, and post-emergence herbicides worldwide. In this context, 90% of the annual sales are used by the agricultural sector, where glyphosate-based agrochemicals are sprayed mainly before planting the crop or post-harvest during the intercropping period to control weeds’ growth. Crops treated with this herbicide are both annual (cereals and oilseeds) and perennial crops (orchards and vineyards).
In Europe, glyphosate is currently approved until December 15th, 2022, and the EU Commission might decide to prolong its use in agricultural lands due to the decision of EFSA to postpone its scientific opinion on the re-approval of glyphosate. For this reason, studying glyphosate dynamics in soil and water is still necessary to outstand its role in groundwater pollution. Site-specific studies for the prevention of water contamination are highly recommended to help decision-makers to set up guidelines for identifying water protection areas for drinking waters, which are nowadays still largely undefined. The identification of unique rules is difficult because of the complex relationship between the agrochemical and the agroecosystem, due to the strongly site-specific adsorption-degradation-transport dynamic which depends on peculiar characteristics of each molecule (adsorption coefficient, solubility, half-life time, etc.), and the pedo-climatic and management variability of the site involved. For instance, in the Veneto region, particular attention must be given to the low-lying plain, where shallow water table conditions increase the risk of groundwater pollution in agricultural areas.
This thesis wants to offer new insights into the peculiar dynamic of glyphosate in soil and water under poorly studied conditions. Extensive studies of the fate in the environment of glyphosate have been carried out in two areas of the Veneto region (high foothills and the low-lying Venetian plain) comprising three different agroecosystems (vineyards, conventional and conservation agriculture) (Chapters 2 and 3), and the factors affecting the adsorption, dissipation, and transport dynamics of the herbicide were identified. Adsorption coefficients for glyphosate have been calculated along the soil profile for several soil layers, down to 70 and 110 cm (Chapters 2 and 3, respectively). In particular, the key role of SOM-chelated Fe and Al on herbicide adsorption has been largely demonstrated, suggesting that a careful analysis of the mineral composition, in addition to that of e.g. pH and soil texture, is required to determine the agroecosystem vulnerability to groundwater pollution. Moreover,
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glyphosate dissipation in soil has been monitored and modeled (Chapter 2), as for AMPA – still poorly investigated – with a new proposed equation to predict its decay rate. The transport of glyphosate and AMPA revealed low mobility in the foothill vineyards, despite some fast vertical movement down to the deepest layer suggested that preferential movements due to likely well-structured soil conditions occurred. A fast movement down to the water table was also found in the low-lying Venetian plain. The modelling study conducted with HYDRUS-1D (Chapter 4) made it possible to identify the drivers leading to contamination. Here, shallow groundwater conditions greatly affected solute transport by modifying the soil structure, enhancing macropores frequency. Moreover, the flow field was modified compared to free drainage conditions, with a reduction of solute exchange between mobile and immobile soil regions that promoted non-equilibrium flows and preferential pathways
Management of Pediatric Febrile Seizures
No full textFebrile seizures (FS), events associated with a fever in the absence of an intracranial infection, hypoglycaemia, or an acute electrolyte imbalance, occur in children between six months and six years of age. FS are the most common type of convulsions in children. FS can be extremely frightening for parents, even if they are generally harmless for children, making it important to address parental anxiety in the most sensitive manner. The aim of this review was to focus on the management of FS in the pediatric age. An analysis of the literature showed that most children with FS have an excellent prognosis, and few develop long-term health problems. The diagnosis of FS is clinical, and it is important to exclude intracranial infections, in particular after a complex FS. Management consists of symptom control and treating the cause of the fever. Parents and caregivers are often distressed and frightened after a FS occurs and need to be appropriately informed and guided on the management of their child's fever by healthcare professionals. Due to the inappropriate use of diagnostic tests and treatments, it is extremely important to improve the knowledge of pediatricians and neurologists on FS management and to standardize the diagnostic and therapeutic work-up
Produrre cultura: dagli stracci, alle cartiere, alla stampa. Scorci sul caso di Bergamo
No full textIl contributo propone un excursus originale sulla produzione cartaria a Bergamo dal Medioevo al primo Ottocento, con un particolare focus su alcuni disegni ricorrenti nelle filigrane, come i triangoli che contraddistinguono la longeva cartiera Cantoni o le lettere "BMO" che si impongono come contrassegno locale dal Settecento. Allo scopo viene valorizzata un'inconsueta fonte diretta: la carta osservata nelle legature di incunaboli della Biblioteca Civica A. Mai di Bergamo riconducibili a una fattura locale.This study offers a unique exploration of paper production in Bergamo, tracing its evolution from the medieval period to the early 19th century. A particular focus is placed on recurring watermark designs, specifically the triangles associated with the long-standing Cantoni paper mill and the "BMO" letters that emerged as a local hallmark from the 18th century onwards. What makes this contribution especially distinctive is its reliance on an unusual direct source: paper observed within the bindings of incunabula held at the Biblioteca Civica A. Mai in Bergamo, which strongly suggests local manufacturing
Dalla vicinia di S. Grata a Venezia, la carriera di Bernardino Benaglio nel XV-XVI secolo
No full textSull'attività del tipografo bergamasco Bernardino Benaglio a Venezia
Per un rinnovamento europeo della cultura e della scienza a Bergamo: Gianantonio Tadini e la Fisica
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
West syndrome: a review and guide for paediatricians
No full textWest syndrome (WS), also known as infantile spasms, occurs in infancy with a peak between 4 and 7 months. Spasms, neurodevelopmental regression and hypsarrhythmia on electroencephalogram (EEG) basically define WS. The International League Against Epilepsy commission classifies the aetiologies of WS into genetic, structural, metabolic and unknown. Early diagnosis and a shorter lag time to treatment are essential for the overall outcome of WS patients. These goals are feasible with the addition of brain magnetic resonance imaging (MRI) and genetic and metabolic testing. The present work analysed the medical literature on WS and reports the principal therapeutic protocols of its management. Adrenocorticotropic hormone (ACTH), vigabatrin (VGB) and corticosteroids are the first-line treatments for WS. There is no unique therapeutic protocol for ACTH, but most of the evidence suggests that low doses are as effective as high doses for short-term treatment, which is generally 2 weeks followed by dose tapering. VGB is generally administered at doses from 50 to 150 mg/kg/day, but its related retinal toxicity, which occurs in 21-34% of infants, is most frequently observed when treatment periods last longer than 6 months. Among corticosteroids, a treatment of 14 days of oral prednisolone (40-60 mg/day) has been considered effective and well tolerated. Considering that an early diagnosis and a shorter lag time to treatment are essential for successful outcomes in these patients, further studies on efficacy of the different therapeutic approaches with evaluation of final outcome after cessation of therapy are needed
Preferential solute transport under variably saturated conditions in a silty loam soil: Is the shallow water table a driving factor?
No full textA shallow water table might enhance preferential solute movement by modifying both the water flow and solute
dynamics. In this study, we estimated soil hydraulic and solute transport parameters through a tracer experiment
in lysimeters comparing different water table levels. In a set-up of 12 lysimeters, the bottom boundary condition
was set as a water table depth of 120 cm, or 60 cm, or as free drainage. A tracer solution of bromide (250 mg l 1,
40 mm) was added to each lysimeter and soil water was sampled with suction cups at different depths for the
following 174 days. Soil water content and matric potential were monitored using TDR probes and electronic
tensiometers at the same depths. Soil hydraulic and solute transport parameters in different soil layers were
estimated by inverse modeling using HYDRUS 1D. Soil hydraulic parameters were estimated from the Mualemvan
Genuchten equations, while both the advection–dispersion (ADE) and physical non-equilibrium mobileimmobile
water (MIM) models were used to describe the solute transport. Moreover, the soil pore network was
analyzed by means of 3D X-ray microtomography. Results showed different solute dynamics between contrasting
water table managements. With free drainage, solute in the immobile domain was negligible, and its transport
was fully associated with the mobile water flow. In contrast, a shallow water table affected the tracer transport,
by modifying a) the soil pore network, with an increase of the macropores and a reduction of the pore connectivity;
b) the flow field, with an increase of immobile water and a reduction of αMIM, indicating slow exchange
between mobile and immobile regions, in turn promoting preferential pathways. Hence, groundwater pollution
might be worsened by preferential solute transport of agrochemicals occurring with shallow water table
conditions
Marcello Piacentini e Luigi Angelini. 1906-1942
No full textL’intervento ricostruisce i rapporti intercorsi tra Marcello Piacentini e Luigi Angelini, iniziati con le vicende del concorso del 1906 per la sistemazione della zona della ex Fiera a Bergamo e poi proseguiti nel corso dei decenni successivi. Attraverso l’analisi delle loro relazioni personali e professionali si esaminano alcune dinamiche di potere messe in campo da Piacentini.
Assieme ai disegni e alle architetture del nuovo centro prende forma il rapporto tra i due, sempre ben distinto gerarchicamente a favore del romano. Inizialmente strumentale, alimentato dalle contorte vicende del concorso, il legame si viene rafforzando negli anni. Punti di distanza sono la distinta sensibilità nel rispetto della città antica; la diversa appartenenza partitica e soprattutto il diverso uso della politica, del tutto spregiudicato nel più celebre architetto
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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