723 research outputs found

    Variability and Trends in Streamflow in Northeast United States

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    Abstract There is general consensus that climate is undergoing change but whether climate change is occurring or not is still being debated in certain scientific, political, and religious quarters. Hydrologic variability influences the design of civil works and assessment of long-term climate change would help improve design criteria. To this end, long-term variability of streamflow was estimated using Shannon entropy. Three statistical tests were applied to determine trends in annual and seasonal daily streamflow with 5% two-sided confidence limit. Daily streamflow data spanning 70 years (from 1943 to 2012) from 669 stream gauge stations located in 23 states in the northeastern part of United States of America, covering six different water regions were employed. The time variability of annual and seasonal daily streamflow was assessed using the Mean Decadal Apportionment Disorder Index ( MDADI ). Analysis showed that in all cases minimum and maximum streamflows had higher variability than average and median streamflows. A significant number of stations exhibited trends. Considering annual minimum, average and median daily streamflows, approximately 50% of the stations followed trends and for almost all these stations trends were increasing. Only for annual maximum daily streamflow, 15% of the stations showed increasing trend and 10% decreasing trend. In terms of geographical distribution, the stations with increasing trend were essentially located along the Atlantic coast and near Great Lakes and in the Upper Mississippi Water Region. Similar considerations apply for seasonal time series as well

    A Cardiovascular Risk Score for Use in Occupational Medicine

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    Cardiovascular disease is one of the most frequent causes of long-term sickness absence from work. The study aims to develop and validate a score to assess the 10-year risk of unsuitability for work accounting for the cardiovascular risk. The score can be considered as a prevention tool that would improve the cardiovascular risk assessment during health surveillance visits under the assumption that a high cardiovascular risk might also translate into high risk of unsuitability for work. A total of 11,079 Italian workers were examined, as part of their scheduled occupational health surveillance. Cox proportional hazards regression models were employed to derive risk equations for assessing the 10-year risk of a diagnosis of unsuitability for work. Two scores were developed: the CROMA score (Cardiovascular Risk in Occupational Medicine) included age, sex, smoking status, blood pressure (systolic and diastolic), body mass index, height, diagnosis of hypertension, diabetes, ischemic heart disease, mental disorders and prescription of antidiabetic and antihypertensive medications. The CROMB score was the same as CROMA score except for the inclusion of only variables statistically significant at the 0.05 level. For both scores, the expected risk of unsuitability for work was higher for workers in the highest risk class, as compared with the lowest. Moreover results showed a positive association between most of cardiovascular risk factors and the risk of unsuitability for work. The CROMA score demonstrated better calibration than the CROMB score (11.624 (p-value: 0.235)). Moreover, the CROMA score, in comparison with existing CVD risk scores, showed the best goodness of fit and discrimination

    Correction

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    Physico-Chemical Modifications Affecting the Activity and Stability of Cu-Based Hybrid Catalysts during the Direct Hydrogenation of Carbon Dioxide into Dimethyl-Ether

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    The direct hydrogenation of CO2 into dimethyl-ether (DME) has been studied in the presence of ferrierite-based CuZnZr hybrid catalysts. The samples were synthetized with three different techniques and two oxides/zeolite mass ratios. All the samples (calcined and spent) were properly characterized with different physico-chemical techniques for determining the textural and morphological nature of the catalytic surface. The experimental campaign was carried out in a fixed bed reactor at 2.5 MPa and stoichiometric H2/CO2 molar ratio, by varying both the reaction temperature (200–300 °C) and the spatial velocity (6.7–20.0 NL∙gcat−1∙h−1). Activity tests evidenced a superior activity of catalysts at a higher oxides/zeolite weight ratio, with a maximum DME yield as high as 4.5% (58.9 mgDME∙gcat−1∙h−1) exhibited by the sample prepared by gel-oxalate coprecipitation. At lower oxide/zeolite mass ratios, the catalysts prepared by impregnation and coprecipitation exhibited comparable DME productivity, whereas the physically mixed sample showed a high activity in CO2 hydrogenation but a low selectivity toward methanol and DME, ascribed to a minor synergy between the metal-oxide sites and the acid sites of the zeolite. Durability tests highlighted a progressive loss in activity with time on stream, mainly associated to the detrimental modifications under the adopted experimental conditions

    Molecular and biological evidence for a severe seedling yellows strain of Citrus tristeza virus spreading in southern Italy

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    Citrus tristeza virus (CTV) outbreaks have been reported in the main citrus-growing regions of Italy in the past 10 years. In some areas where eradication efforts failed to suppress spread, high CTV incidence is now observed. Recently, potentially severe CTV strains were detected in Calabria (southern Italy), one of the major citrus-growing area. As a result, investigations of the virulence and molecular features of CTV populations spreading in this region were undertaken. Virus was detected by enzyme-linked immunosorbent assay (ELISA) using a broad spectrum polyclonal antiserum, and was differentiated into potential virulent categories with the severe-strain discriminating monoclonal antibody MCA13. Isolate genotyping was conducted using reverse-transcription polymerase chain reaction (RT-PCR) with multiple molecular markers (MMM), single-strand conformation polymorphism (SSCP) analysis of the amplicons from the genes coding for the coat protein (CP) p25 and the non-structural p20 protein as well as sequence analysis. Based on the serological reactivity, the isolates were differentiated in two distinct serogroups: MCA13-reactive and MCA13 non-reactive. Similarly, based on the molecular profile, the isolates were grouped in two genetically distinct phylogenetic clusters, and associated either with a T30-like or with a T3-like genotype. These data were related to the results of biological indexing on standard indicator plants, which distinguished isolates causing mild or severe seedling yellow reactions. The study has demonstrated the presence of MCA13-reactive isolates associated with a T3-like genotype and causing severe seedling yellows in sour orange, grapefruit and lemon seedlings, and stem pitting in Mexican lime

    A multicenter retrospective cohort study evaluating the clinical outcomes of patients with coagulopathy undergoing transcatheter arterial embolization (tae) for acute non-neurovascular bleeding

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    Background and Objectives: Transcatheter arterial embolization (TAE) is the mainstay of treatment for acute major hemorrhage, even in patients with coagulopathy and spontaneous bleeding. Coagulopathy is associated with worsening bleeding severity and higher mortality and clinical failure rates. Furthermore, some unanswered questions remain, such as the definition of coagulopathy, the indication for TAE or conservative treatment, and the choice of embolic agent. This study aims to assess the efficacy and safety of TAE for spontaneous non-neurovascular acute bleeding in patients with coagulopathy. Materials and Methods: This study is a multicenter analysis of retrospectively collected data of consecutive patients with coagulopathy who had undergone, from January 2018 to May 2023, transcatheter arterial embolization for the management of spontaneous hemorrhages. Results: During the study interval (January 2018–May 2023), 120 patients with coagulopathy underwent TAE for spontaneous non-neurovascular acute bleeding. The abdominal wall was the most common bleeding site (72.5%). The most commonly used embolic agent was polyvinyl alcohol (PVA) particles or microspheres (25.0%), whereas coils and gelatin sponge together accounted for 32.5% of the embolic agents used. Technical success was achieved in all cases, with a 92.5% clinical success rate related to 9 cases of rebleeding. Complications were recorded in 12 (10%) patients. Clinical success was significantly better in the group of patients who underwent correction of the coagulopathy within 24 h of TAE. Conclusions: Transcatheter arterial embolization (TAE) is effective and safe for the management of acute non-neurovascular bleeding in patients with coagulopathy. Correction of coagulopathy should not delay TAE and vice versa, as better clinical outcomes were noted in the subgroup of patients undergoing correction of coagulopathy within 24 h of TAE

    Produzione, qualità e analisi della filiera produttiva del lino da fibra in Italia

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    Fibre flax (Linum usitatissimum L.) is disappeared from the ltalian crop systems, while the textile industry has reached a leading position. The reintroduction of the crop is than potentially promising but the crop techniques and the production processes have to be set up. In 12 environments: crop development and growth, cultivar response, straw, fibre and seed yields, and fibre quality were analysed in the 1992-98 period. The data pointed out crop cycles of 176 and 110 d for the autumn and the spring sowing time respectively, corresponding to 1125 and 990°C d cumulated growing degree. Straw yield at pulling was on average of 6.3 t ha-1, with relevant differences among years and environrnents. Early maturity cultivar yielded more in the less favourable sites. N fertilization was occasionally relevant, and a generally distributions of 60 kg N ha-1 was the more effective. In the Mediterranean environments, with the autumn, sowing flax was more productive and the yield steady. The long fibre ratio was often low (10-13%) and the quality uneven because of the insufficient cleanliness due to retting difficulties. Occasionally, the value of the fibre was affected by the insufficient stem length. In the less dense crop, the seed yield was on average 0.9 t ha-1. Such productions were similar to those assessed for the more dense crop. In conclusion: because of the complexity of the interactions among the crop growth, the yield, the retting process and the fibre quality flax reintroduction is doubtful. In the production processes retting seems to be the crucial phase. Il lino da fibra (Linum usitatissimum L.) è da tempo assente negli ordinamenti colturali italiani, mentre è assai importante l'industria di filatura. La reintroduzione della coltura appare quindi potenzialmente promettente, ma richiede la messa a punto dell'agrotecnica e della filiera produttiva. Nel periodo 1992-1998 in 12 ambienti sono stati esaminati: lo sviluppo e la crescita della coltura, l'adattamento di cultivar, la produzione di paglia, fibra e seme, la resa alla stigliatura, la qualità della fibra. I dati raccolti evidenziano cicli colturali in media di 176 e 110 d rispettivamente per le semine autunnali (ambienti del centro-sud) e vemino-primaverili; corrispondenti a somme termiche di 1125 e 990°C d. La produzione di paglia alla estirpatura è stata in media di 6.3 t ha-1 con valori assai variabili tra annate e ambienti. Le varietà a ciclo corto sono apparse migliori nelle condizioni difficili. L'effetto della concimazione azotata è apparsa talvolta rilevante e comunque con dosi ottimali prossime a 60 kg ha-1 di N. Negli ambienti del centro-sud le semine autunnali si sono dimostrate spesso le più interessanti e sicure. La resa in fibra lunga è stata bassa (10-13%) e la qualità variabile per la scarsa pulizia dovuta alle difficoltà di macerazione. La modesta lunghezza tecnica dello stelo sovente riduce il valore del prodotto. In coltura rada, la produzione di seme è variata da 0.5 a 1.5 t ha-1; tali valori non si sono discostati in modo apprezzabile da quelli ottenuti in coltura fitta. In conclusione, la diffusione del lino appare problematica per le complesse interazioni tra la produzione, il processo di macerazione e la qualità della fibra. Soprattutto la macerazione appare il passaggio chiave
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