1,354,210 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
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
Recent morpho-sedimentological change on a “human-dominated” delta: the case of the Arno River (Italy)
No full textThe evolution of the Arno River mouth has been tightly connected to human activities in the last 500 years. Two major events drove its development within this timespan, both attributed to anthropic interventions. As the strongest storms typically come from southwest in this sector of the Tuscany coast, in 1606 the southwest-oriented mouth was artificially modified to point towards northwest to avoid devastating floods inland when the storms coincided with river overflows. The new orientation increased the amount of sediments reaching the sea, which led to a huge growth of the delta. The mouth continued to prograde up to the mid-1800s, when several human activities (riverbed dredging, dam construction, slope reforestation) contributed to decreasing the Arno bedload. Towards the end of the century the delta was struck by strong erosive processes: on the left side hard structures were built to protect a seaside village, whereas the right side was left free to erode, which led to the present asymmetrical geometry of the mouth (about 300 m landward offset). The analysis of a series of bathymetric surveys within the 2008-2014 time interval provided insights about the recent evolution of the Arno River mouth. The results showed the significant back and forth mobility of the mouth bar along with swift changes of the shape. At times the mouth bar is located just inside the last tract of the river, and never more than a few tens of meters outside the mouth. On regards to the geometry, the typical profile is frequently replaced by a distinct, incised bar characterized by a 2 m-high crest. All these elements may be related to the asymmetry of the delta determined by the strong human pressure, that may have affected the morpho-sedimentological behavior of the Arno River delta. Lately, the anthropic constraints have likely been more effective than the natural factors in driving the recent evolution of the river mouth and adjusting to a “human-dominated” behavior. These data may be useful to better understand the ongoing processes on such deltas, which are gaining increasing attention especially in the Mediterranean area
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
Tuning the Photophysics of Two-Arm Bis[(dimethylamino)styryl]benzene Derivatives by Heterocyclic Substitution
No full textThe identification of novel molecular systems with high fluorescence and significant non-linear optical (NLO) properties is a hot topic in the continuous search for new emissive probes. Here, the photobehavior of three two-arm bis[(dimethylamino)styryl]benzene derivatives, where the central benzene was replaced by pyridine, furan, or thiophene, was studied by stationary and time-resolved spectroscopic techniques with ns and fs resolution. The three molecules under investigation all showed positive fluorosolvatochromism, due to intramolecular charge-transfer (ICT) dynamics from the electron-donor dimethylamino groups, and significant fluorescence quantum yields, because of the population of a planar and emissive ICT state stabilized by intramolecular hydrogen-bond-like interactions. The NLO properties (hyperpolarizability coefficient and TPA cross-section) were also measured. The obtained results allowed the role of the central heteroaromatic ring to be disclosed. In particular, the introduction of the thiophene ring guarantees high fluorescent quantum yields irrespective of the polarity of the medium, and the largest hyperpolarizability coefficient because of the increased conjugation. An important and structure-dependent involvement of the triplet state was also highlighted, with the intersystem crossing being competitive with fluorescence, especially in the thiophene derivative, where the triplet was found to significantly sensitize molecular oxygen even in polar environment, leading to possible applications in photodynamic therapy
Going 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
Competition between fluorescence and triplet production ruled by nitro groups in one-arm and two-arm styrylbenzene heteroanalogues
No full textThe competition between excited state deactivation processes in mono and double-arm push-pull systems bearing pyridine, furan or thiophene (electron donors) and nitro groups (electron acceptors) was investigated in several solvents through nanosecond and femtosecond transient absorption spectroscopy. Triplet population is the main deactivation pathway for the mono-arm compounds. The large triplet production is mainly ascribed to 3(n,π∗) states almost isoenergetic to S1, introduced by nitro groups, as predicted by TD-DFT calculations. The large triplet population may indeed be exploited to produce long-lived excitons for photovoltaic and optoelectronic applications. Two-arm furan and thiophene derivatives instead undergo strong ultrafast intramolecular charge transfer (ICT), which is responsible for their appreciable two-photon absorption cross-sections. In this case, significant fluorescence and singlet oxygen quantum yields are obtained, making these two compounds interesting as potential traceable photosensitizers in photodynamic therapy. This journal i
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
Intestinal lymphangiectasia in a 3-month-old girl: A case report of Hennekam syndrome caused by CCBE1 mutation
No full textRATIONAL: Intestinal lymphangiectasia (IL) is a rare disease characterized by dilatation and rupture of intestinal lymphatic channels leading to protein-losing enteropathy. IL is classified as primary and secondary types. PATIENT CONCERNS: A 3-month-old girl born at term from vaginal delivery with an APGAR score of 10/10 and birth weight of 4.310 g (>97° percentile) was admitted to our hospital because of increasing abdominal tenderness and diarrhea. At first examination, she presented an abdominal circumference of 60 cm, edema of the lower extremities and vulva, and facial dysmorphisms (hypertelorism, flat nasal bridge, flat mid-face). DIAGNOSIS: Once admitted, ultrasonography showed a large amount of ascites, while blood laboratory investigations revealed severe hypoproteinemia, hypoalbuminemia and hypogammaglobulinemia. Lymphoscintigraphy with 99m-Tc-nanocolloid demonstrated abnormal leakage of the tracer in the abdomen as evidence of IL. To detect a possible secondary, exams were performed and demonstrated positive antibody titres for CMV-IgM and IgG in blood and CMV-DNA positivity in blood, urine, saliva, maternal milk, and gastric and duodenal biopsies. Genetic investigations identified the genomic variant c.472C>T of the CCBE1 gene, coding for a protein variant (p.Arg158Cys), in homozygosity. INTERVENTIONS: Total parenteral nutrition was started and continued for a total of 18 days, then gradually bridged by enteral nutrition with a special formula. In addition, antiviral therapy for CMV infection was added first with intravenous ganciclovir for 14 days, resulting in the disappearance of blood viral load after 7 days of therapy and then with valganciclovir per os for another 30 days. OUTCOMES: The clinical course of the child gradually improved. A few days after starting treatments, lower extremities and vulvar edema disappeared, and abdominal circumference gradually decreased to a stable value of 38 cm, without any ultrasonographic signs of ascites left. Moreover, serum albumin and IgG rose to normal values after 3 months (4.3 g/dL and 501 mg/dL, respectively). LESSONS: This case suggests that in presence of IL both primary and secondary causes should be evaluated. On the other hand, genetic diagnosis is crucial not only for diagnosis but also for prognosis in HS. Life expectancy and quality could deeply vary among different gene mutations and protein variants of the same gene. Further studies and case reports are needed to better understand the clinical meaning of these genetic results and the role of CMV as trigger of IL
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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