180 research outputs found

    Impact of reforestations with exotic and native species on water repellency of forest soils

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    Forest duff layer is usually water repellent due to the hydrophobic organic compounds resulting from degradation of tree tissues. Transition from hydrophobic to wettable conditions, or vice versa, is largely controlled by water content. The objective of this investigation was to assess the influence of soil moisture on the degree of soil water repellency (WR) in exotic and native tree forests. Occurrence of WR was investigated by the water drop penetration time (WDPT) and the ethanol percentage (EP) tests. Sampling was conducted in the forest soils of two exotic species (Pinus pinaster, P, and Eucaliptus camaldulensis, E), used in the past for reforestation, and two native species (Quercus ilex, L, and Quercus pubescens, R). The WDPT vs. \u3b8 relationships exhibited a decreasing trend with a transition from hydrophobic to wettable conditions in the range \u3b8 = 0.14 - 0.19 cm3cm-3. The EP vs. \u3b8 relationships showed a maximum in the range \u3b8 = 0.10 - 0.15 cm3cm-3. Hydrophobicity in soils of native species persisted at relatively higher water content compared to exotic ones and it is expected to influence the hydrological processes to a greater extent

    Application of minidisk infiltrometer to estimate water repellency in Mediterranean pine forest soils

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    Assessment of soil water repellency (SWR) was conducted in the decomposed organic floor layer (duff) and in the mineral soil layer of two Mediterranean pine forests, one in Italy and the other in Spain, by the widely-used water drop penetration time (WDPT) test and alternative indices derived from infiltration experiments carried out by the minidisk infiltrometer (MDI). In particular, the repellency index (RI) was calculated as the adjusted ratio between ethanol and water soil sorptivities whereas the water repellency cessation time (WRCT) and the specifically proposed modified repellency index (RIm) were derived from the hydrophobic and wettable stages of a single water infiltration experiment. Time evolution of SWR and vegetation cover influence was also investigated at the Italian site. All indices unanimously detected severe SWR conditions in the duff of the pine forests. The mineral subsoils in the two forests showed different wettability and the clay-loam subsoil at Ciavolo forest was hydrophobic even if characterized by organic matter (OM) content similar to the wettable soil of an adjacent glade. It was therefore assumed that the composition rather than the total amount of OM influenced SWR. The hydraulic conductivity of the duff differed by a factor of 3.8-5.8 between the two forested sites thus influencing the vertical extent of SWR. Indeed, the mineral subsoil of Javea showed wettable or weak hydrophobic conditions probably because leaching of hydrophobic compounds was slowed or prevented at all. Estimations of SWR according to the different indices were in general agreement even if some discrepancies were observed. In particular, at low hydrophobicity levels the SWR indices gathered from the MDI tests were able to signal sub-critical SWR conditions that were not detected by the traditional WDPT index. The WRCT and modified repellency index RIm yielded SWR estimates in reasonable agreement with those obtained with the more cumbersome RI test and, therefore, can be proposed as alternative procedures for SWR assessment

    Comparison between adenosine triphosphate bioluminescence and aerobic colony count to assess surface sanitation in the hospital environment

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    Background: Adenosine triphosphate bioluminescence produced by the firefly luciferase has been successfully introduced to verify cleaning procedures in the food industry according to the Hazard Analysis Critical Control Point program. Our aim was to evaluate the reliability of bioluminescence as a tool to monitor the effectiveness of sanitation in healthcare settings, in comparison with the microbiological gold standard. Methods: 614 surfaces of various material were randomly sampled in Policlinico University Hospital units in Palermo, Italy, to detect adenosine triphosphate bioluminescence and aerobic colony count. Linear regression model and Pearson correlation coefficient were used to estimate the relationship between the two variables of the study. Results: Aerobic colony count median was 1.71 colony forming units/cm2 (interquartile range = 3.8), whereas adenosine triphosphate median was 59.9 relative light units/cm2 (interquartile range = 128.3). Pearson coefficient R2 was 0.09. Sensitivity and specificity of bioluminescence test with respect to microbiology were 46% and 71%, whereas positive predictive value and negative predictive value were 53% and 65%, respectively. Conclusion: According to our results, there seemed to be no linear correlation between aerobic colony count and adenosine triphosphate values, suggesting that current bioluminescence technology has not any proportional relationships with culturable microbes contaminating environmental surfaces in health-care settings

    Advances in Ecohydrology for Water Resources Optimization in Arid and Semi-Arid Areas

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    Conserving water resources is a current challenge that will become increasingly urgent in future due to climate change. The arid and semi-arid areas of the globe are expected to be particularly affected by changes in water availability. Consequently, advances in ecohydrology sciences, i.e., the interplay between ecological and hydrological processes, are necessary to enhance the understanding of the critical zone, optimize water resources’ usage in arid and semi-arid areas, and mitigate climate change. This Special Issue (SI) collected 10 original contributions on sustainable land management and the optimization of water resources in fragile environments that are at elevated risk due to climate change. In this context, the topics mainly concern transpiration, evapotranspiration, groundwater recharge, deep percolation, and related issues. The collection of manuscripts presented in this SI represents knowledge of ecohydrology. It is expected that ecohydrology will have increasing applications in the future. Therefore, it is realistic to assume that efforts to increase environmental sustainability and socio-economic development, with water as a central theme, will have a greater chance of success

    Challenges in the Diagnosis and Management of Bacterial Lung Infections in Solid Organ Recipients: A Narrative Review

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    Respiratory infections pose a significant threat to the success of solid organ transplantation, and the diagnosis and management of these infections are challenging. The current narrative review addressed some of these challenges, based on evidence from the literature published in the last 20 years. Specifically, we focused our attention on (i) the obstacles to an etiologic diagnosis of respiratory infections among solid organ transplant recipients, (ii) the management of bacterial respiratory infections in an era characterized by increased antimicrobial resistance, and (iii) the development of antimicrobial stewardship programs dedicated to solid organ transplant recipient

    Analysis of Geometrical Relationships and Friction Losses in Small-Diameter Lay-Flat Polyethylene Pipes

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    [EN] The use of lay-flat polyethylene pipes to irrigate horticultural crops has been receiving widespread attention in the last decade, due to the significant improvements in their hydraulic performance, their potentially high application efficiency, and their limited installation costs. However, even if hydraulic design procedures for conventional microirrigation systems are fairly well established, there is still the need to know how different pipe-wall thicknesses of lay-flat pipes can affect the pipe geometry under different operating pressures as well as the related consequences on friction losses. This paper, after comparing two different procedures (caliper and photographic) to assess the geometry of lay-flat polyethylene pipes under different operating pressures, analyzes the friction losses per unit of pipe length, J, in order to identify and to assess a procedure for their evaluation. Hydrostatic tests, initially carried out on pipes with wall thicknesses of 6, 8, and 10 thousandth of an inch (mil), evidenced that the pipe dimensions measured with both methods are quite similar, despite the generally higher standard deviations characterizing caliper measurements when compared to photographic method. Tests allowed to verify that most of the changes in pipe dimensions occur within a range of pressure from 0 kPa to about 30 kPa, with pipe horizontal width and vertical height quite similar at higher pressures and pipes have a tendency to become circular. Additionally, due to the elasticity of the material, over a certain limit of water pressure, both the pipe dimensions tend to rise, with a trend depending on pipe thickness. According to the experimental data, the relationships between pipe effective diameter and water pressure were then determined for the three considered pipes. Moreover, based on measured friction losses and pipe effective diameters, it was confirmed that the relationship between the Darcy-Weisbach friction factor, f, and the Reynolds number, R, can be described by a power equation in which, by assuming a value of -0.25 for the exponent, it results a coefficient c = 0.285, lower than the theoretical. For the three investigated pipes the errors associated to estimated J were finally evaluated by considering (1) the experimental relationships between friction factor and Reynolds number as well as between pipe diameter and operating pressure (Case A); (2) the same value of c, but pipe effective diameters of 16.20, 16.10, and 15.85 mm corresponding to p = p(lim) (Case B); (3) the standard procedure, with a value of c = 0.302 and the pipe diameter equal to 16.10 mm, as suggested by the manufacturer. The results evidenced that suitable estimations of J need to account for the variations of the pipe effective diameter with water pressure. On the other hand, incorrect values of pipe diameter combined with inexact values of the friction factor generate inaccurate estimations of friction losses, with unavoidable consequences in pipe design. (C) 2015 American Society of Civil Engineers.The research was cofinanced by Universita di Palermo (FFR 2011) and Ministero dell'Istruzione, dell'Universita e della Ricerca (PRIN 2010). All the authors setup the research and discussed the results. V. Alagna and D. Autovino carried out the experimental measurements and G. Provenzano wrote the paper. A special thank to the Committee for International Relations Office (CORI) of University of Palermo to support the research cooperation with the University of Valencia.Provenzano, G.; Alagna, V.; Autovino, D.; Manzano Juarez, J.; Rallo, G. (2016). Analysis of Geometrical Relationships and Friction Losses in Small-Diameter Lay-Flat Polyethylene Pipes. Journal of Irrigation and Drainage Engineering. 142(2):1-9. https://doi.org/10.1061/(ASCE)IR.1943-4774.0000958S19142

    Gastrointestinal colonization with multidrug-resistant Gram-negative bacteria during extracorporeal membrane oxygenation: effect on the risk of subsequent infections and impact on patient outcome

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    Background: In ICU patients, digestive tract colonization by multidrug-resistant (MDR) Gram-negative (G 12) bacteria is a significant risk factor for the development of infections. In patients undergoing extracorporeal membrane oxygenation (ECMO), colonization by MDR bacteria and risk of subsequent nosocomial infections (NIs) have not been studied yet. The aim of this study is to evaluate the incidence, etiology, risk factors, impact on outcome of gastrointestinal colonization by MDR G 12 bacteria, and risk of subsequent infections in patients undergoing ECMO. Methods: This is a retrospective analysis of prospectively collected data: 105 consecutive patients, treated with ECMO, were admitted to the ICU of an Italian tertiary referral center (San Gerardo Hospital, Monza, Italy) from January 2010 to November 2015. Rectal swabs for MDR G 12 bacteria were cultured at admission and twice a week. Only colonization and NIs by MDR G 12 bacteria were analyzed. Results: Ninety-one included patients [48.5 (37\u201356) years old, 63% male, simplified acute physiology score II 37 (32\u201347)] underwent peripheral ECMO (87% veno-venous) for medical indications (79% ARDS). Nineteen (21%) patients were colonized by MDR G 12 bacteria. Male gender (OR 4.03, p = 0.029) and duration of mechanical ventilation (MV) before ECMO > 3 days (OR 3.57, p = 0.014) were associated with increased risk of colonization. Colonized patients had increased odds of infections by the colonizing germs (84% vs. 29%, p < 0.001, OR 12.9), longer ICU length of stay (LOS) (43 vs. 24 days, p = 0.002), MV (50 vs. 22 days, p < 0.001) and ECMO (28 vs. 12 days, p < 0.001), but did not have higher risk of death (survival rate 58% vs. 67%, p = 0.480, OR 0.68). Infected patients had almost halved ICU survival (46% vs. 78%, p < 0.001, OR 4.11). Conclusions: In patients undergoing ECMO for respiratory and/or circulatory failure, colonization by MDR G 12 bacteria is frequent and associated with more the tenfold odds for subsequent infection. Those infections are associated with an increased risk of death

    Genetic Mapping of the Incompatibility Locus in Olive and Development of a Linked Sequence-Tagged Site Marker

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    The genetic control of self-incompatibility (SI) has been recently disclosed in olive. Inter-varietal crossing confirmed the presence of only two incompatibility groups (G1 and G2), suggesting a simple Mendelian inheritance of the trait. A double digest restriction associated DNA (ddRAD) sequencing of a biparental population segregating for incompatibility groups has been performed and high-density linkage maps were constructed in order to map the SI locus and identify gene candidates and linked markers. The progeny consisted of a full-sib family of 229 individuals derived from the cross \u2018Leccino\u2019 (G1) 7 \u2018Dolce Agogia\u2019 (G2) varieties, segregating 1:1 (G1:G2), in accordance with a diallelic self-incompatibility (DSI) model. A total of 16,743 single nucleotide polymorphisms was identified, 7,006 in the female parent \u2018Leccino\u2019 and 9,737 in the male parent \u2018Dolce Agogia.\u2019 Each parental map consisted of 23 linkage groups and showed an unusual large size (5,680 cM in \u2018Leccino\u2019 and 3,538 cM in \u2018Dolce Agogia\u2019). Recombination was decreased across all linkage groups in pollen mother cells of \u2018Dolce Agogia,\u2019 the parent with higher heterozygosity, compared to megaspore mother cells of \u2018Leccino,\u2019 in a context of a species that showed exceptionally high recombination rates. A subset of 109 adult plants was assigned to either incompatibility group by a stigma test and the diallelic self-incompatibility (DSI) locus was mapped to an interval of 5.4 cM on linkage group 18. This region spanned a size of approximately 300 Kb in the olive genome assembly. We developed a sequence-tagged site marker in the DSI locus and identified five haplotypes in 57 cultivars with known incompatibility group assignment. A combination of two single-nucleotide polymorphisms (SNPs) was sufficient to predict G1 or G2 phenotypes in olive cultivars, enabling early marker-assisted selection of compatible genotypes and allowing for a rapid screening of inter-compatibility among cultivars in order to guarantee effective fertilization and increase olive production. The construction of high-density linkage maps has led to the development of the first functional marker in olive and provided positional candidate genes in the SI locus

    Proteome Regulation during Olea europaea Fruit Development

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    Widespread in the Mediterranean basin, Olea europaea trees are gaining worldwide popularity for the nutritional and cancer-protective properties of the oil, mechanically extracted from ripe fruits. Fruit development is a physiological process with remarkable impact on the modulation of the biosynthesis of compounds affecting the quality of the drupes as well as the final composition of the olive oil. Proteomics offers the possibility to dig deeper into the major changes during fruit development, including the important phase of ripening, and to classify temporal patterns of protein accumulation occurring during these complex physiological processes.In this work, we started monitoring the proteome variations associated with olive fruit development by using comparative proteomics coupled to mass spectrometry. Proteins extracted from drupes at three different developmental stages were separated on 2-DE and subjected to image analysis. 247 protein spots were revealed as differentially accumulated. Proteins were identified from a total of 121 spots and discussed in relation to olive drupe metabolic changes occurring during fruit development. In order to evaluate if changes observed at the protein level were consistent with changes of mRNAs, proteomic data produced in the present work were compared with transcriptomic data elaborated during previous studies.This study identifies a number of proteins responsible for quality traits of cv. Coratina, with particular regard to proteins associated to the metabolism of fatty acids, phenolic and aroma compounds. Proteins involved in fruit photosynthesis have been also identified and their pivotal contribution in oleogenesis has been discussed. To date, this study represents the first characterization of the olive fruit proteome during development, providing new insights into fruit metabolism and oil accumulation process
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