Structural Changes in the Red Spruce-Fraser Fir Forest

Since the early 1900s the southern Appalachian red spruce (Picea rubens Sarg.)-Fraser fir (Abies piceae (Pursh) Poir.) forests have been subjected to numerous destructive influences. Historical logging practices, fire, exotic insect infestations, acidic deposition, and global climate change have demonstratively altered the structure and composition of this fragile ecosystem. Most profound was the discovery in 1957 of the balsam woolly adelgid (Adelges piceae Ratz. Homoptera: Adelgidae ), an exotic sap-sucking aphid. A study was initiated in the Great Smoky Mountains National Park, which contains 74% of the red spruce-Fraser ecosystem. Thirty-six 20x20 m permanent plots untouched by logging were established in 1990 on five high elevation mountain peaks to monitor the changes in the forest and were re-sampled in 2000-01. From the late 1940s to 1990-91, live fir basal area decreased by 6.64 m2/ha. Between 1990-91 and 2000 live fir density increased by 156 stems/ha. Despite the increase in density this second generation of Fraser fir remained sparse compared to the 1940s. All of the species in the sapling cohort (\u3c5cm diameter at breast height (dbh), and ≥1.37m tall) increased showing a positive response to overstory deterioration. All species in the seedling cohort (\u3c1.37m tall) decreased exhibiting the effects of inhibition from the sapling layer, voids in seed years, and germination difficulty from lack of soil moisture. Mean age of all seedling and sapling size fir decreased since 190-91 suggesting a faster growing second generation in 2000. Mortality rates of all overstory species decreased since the late 1980s. However, the future of this young cohort of understory trees in unknown. A dense even-aged forest could create the ideal habitat of the adelgid, causing another rapid outbreak. If adelgid populations do not stabilize and Fraser fir does not develop a resistance this cohort could be in jeopardy once it reaches maturity. Provided it lives long enough to produce viable seed it will become a two-aged forest never reaching the old growth un-even aged structure that existed prior to infestation

DETECTION OF STX2 COLIPHAGES IN STRAIN OF ESCHERICHIA COLI ISOLATED FROM BOVINE FLEECE AND MILK FILTERS

Lambda(4)-phage vectors of gene codifying for synthesis of Shiga-toxins are suspected to be involved in the virulence evolution of Vero-Toxin producing Escherichia coli(VTEC). Herds of domestic or wild ruminants are reservoirs of these bacteria, but excretion with faeces is more frequent in groups of heifers and feeder calves. Studies have shown that slurries produced by infected herds are often positive for VTEC and that Stx2 carrying lambda coliphages can be isolated. These viruses can induce lysogenic cycles only in some strain of Escherichia coli and the Stx gene is then integrated in the bacterial chromosome. When these bacteria also posses other virulence traits, like those responsible for the intimate attachment to the enteric mucosal cells (eae or saa) the recombinant strains might became pathogen for humans. Our research was aimed at detecting the coliphages form ten Stx2 positive strains isolated in our previous studies. We have included strains, possessing or not the 'eae' genes. In addition we have used other isolates originating from slaughterhouses, with the aim of evaluating their susceptibility to the isolated 4-phages. Following induction of a lytic cycle with mitomycin C, the strains were screened by hybridization of plaque blots with Stx2 probes. The purified extracts of eight of the ten strains produced plaque/halos of lysis in cultures of susceptible strains, thus showing these strains were infected by inducible phages, but only one proved to be Stx2 carrier. Attempt to obtain new lysogens using the purified Stx2 phage with other strains 'eae' positive and STx negative isolated from slaughterhouses were unsuccessful. Stx2 lysogens were obtained only using the reference strains DM1187

Constraining statistical-model parameters using fusion and spallation reactions

Peer reviewe

Life cycle assessment and feasibility analysis of a combined chemical looping combustion and power-to-methane system for CO2 capture and utilization

The ability to store effectively excess of electrical energy from peaks of production is key to the development of renewable energies. Power-To-Gas, and specifically Power-To-Methane represents one of the most promising option. This works presents an innovative process layout that integrates Chemical Looping Combustion of solid fuels and a Power-to-Methane system. The core of the proposed layout is a multiple interconnected fluidized bed system (MFB) equipped with a two-stage fuel reactor (t-FR). Performances of the system were evaluated by considering a coal as fuel and CuO supported on zirconia as oxygen carrier. A kinetic scheme comprising both heterogeneous and homogeneous reactions occurring in the MFB was considered. The methanation unit was modelled developing a thermodynamic calculation method based on minimization of the free Gibbs energy. The performance of the system was evaluated by considering that the CO/CO2 stream coming from the t-FR reacts over Ni supported on alumina catalyst with a pure H2 stream generated by an array of electrolysis cells. The number of cells to be stacked in the array was evaluated by considering that a constant H2 production able to convert the whole CO/CO2 stream produced by the CLC process should be attained. The environmental performance of the proposed process was quantified using the Life Cycle Assessment (LCA) methodology. The analysis shows i) that the majority originate from the production and disposal of the oxygen carrier used in the t-FR, and ii) that reusing part of the oxygen produced by the electrolysis cells improves significantly the environmental performance of the proposed process

Flood scenario spatio-temporal mapping via hydrological and hydrodynamic modelling and a remote sensing dataset: A case study of the Basento river (Southern Italy)

Today, hydrological and hydraulic modelling are essential tools for flood risk management, although these models are still affected by elements of uncertainty that needs to be reduced by optimizing their results. The present research aims to implement an operational mechanism on the Basento river basin in Southern Italy based on the cascading use of a physically based concentrated-parameter hydrological model for the estimation of flood hydrographs, and a two-dimensional hydraulic model for flood mapping. The calibration of the hydrological model uses physical information to reduce the initial range of the set parameter values, and an automated optimisation procedure based on a genetic algorithm to find optimal values of the model parameters by comparing simulated and observed data for the 2013 flood event. To calibrate the hydraulic model, a series of flood maps extracted from multi-temporal SAR images was used. In addition, validation of the hydrological and hydraulic models was carried out on March 2011 flood event. The results show the reliability of the models during both calibration and validation, with the hydrological model achieving a Nash-Sutcliffe Efficiency coefficient between 0.86 and 0.91, and the hydraulic model leading to results with an accuracy close to 70 %. Considering the significance of the results, the developed modelling chain was used to simulate future event scenarios for risk management assessment and could operate as an early warning system

Life cycle assessment and feasibility analysis of a combined chemical looping combustion and power-to-methane system for CO2 capture and utilization

The ability to store effectively excess of electrical energy from peaks of production is key to the development of renewable energies. Power-To-Gas, and specifically Power-To-Methane represents one of the most promising option. This works presents an innovative process layout that integrates Chemical Looping Combustion of solid fuels and a Power-to-Methane system. The core of the proposed layout is a multiple interconnected fluidized bed system (MFB) equipped with a two-stage fuel reactor (t-FR). Performances of the system were evaluated by considering a coal as fuel and CuO supported on zirconia as oxygen carrier. A kinetic scheme comprising both heterogeneous and homogeneous reactions occurring in the MFB was considered. The methanation unit was modelled developing a thermodynamic calculation method based on minimization of the free Gibbs energy. The performance of the system was evaluated by considering that the CO/CO2 stream coming from the t-FR reacts over Ni supported on alumina catalyst with a pure H2 stream generated by an array of electrolysis cells. The number of cells to be stacked in the array was evaluated by considering that a constant H2 production able to convert the whole CO/CO2 stream produced by the CLC process should be attained. The environmental performance of the proposed process was quantified using the Life Cycle Assessment (LCA) methodology. The analysis shows i) that the majority originate from the production and disposal of the oxygen carrier used in the t-FR, and ii) that reusing part of the oxygen produced by the electrolysis cells improves significantly the environmental performance of the proposed process

Unified description of fission in fusion and spallation reactions

We present a statistical-model description of fission, in the framework of compound-nucleus decay, which is found to simultaneously reproduce data from both heavy-ion-induced fusion reactions and proton-induced spallation reactions at around 1 GeV. For the spallation reactions, the initial compound-nucleus population is predicted by the Li\`{e}ge Intranuclear Cascade Model. We are able to reproduce experimental fission probabilities and fission-fragment mass distributions in both reactions types with the same parameter sets. However, no unique parameter set was obtained for the fission probability. The introduction of fission transients can be offset by an increase of the ratio of level-density parameters for the saddle-point and ground-state configurations. Changes to the finite-range fission barriers could be offset by a scaling of the Bohr-Wheeler decay width as predicted by Kramers. The parameter sets presented allow accurate prediction of fission probabilities for excitation energies up to 300 MeV and spins up to 60 \hbar.Comment: 16 pages, 20 figures. Submitted to Phys. Rev.

Effectiveness of the Thermal Treatments Used for Curd Stretching in the Inactivation of Shiga Toxin-Producing O157 and O26 Escherichia coli

The kneading treatment of the fresh curd in hot water is a critical control point in the manufacturing of mozzarella. Factors such as the ratio between hot water and curd mass, the rheological properties, and the mixing and kneading activity affect the processing time and the internal temperature of the curd. The aim of this study was to investigate the effect of thermal treatments on the fate of Shiga toxin-producing Escherichia coli (STEC). Nine curd samples (weight 160–270 g) were artificially contaminated with O157 or O26 STEC and stretched in hot water (90–95°C) for 5–10 min. Depending on the heating process and spinning, different nonisothermal profiles were recorded. Observed reductions of O157 and O26 STEC varied between 1.01 and more than 5.38 log⁡MPN (Most Probable Number)/g at the end of the temperature treatments. Further, nonisothermal log-linear tail models were developed to compare observed reductions for O157 and O26 VTEC under variable temperature conditions. Results obtained showed that the comparison of predictions provided by the dynamic model with observations described well the linear inactivation pattern since nonsignificant differences were denoted at all profiles tested. The dynamic model developed can be useful to evaluate the effectiveness of the thermal treatments used in the manufacturing of mozzarella in the inactivation of STEC

Effects of Dipeptidyl Peptidase-4 Inhibitor Linagliptin on Left Ventricular Dysfunction in Patients with Type 2 Diabetes and Concentric Left Ventricular Geometry (the DYDA 2TM Trial). Rationale, Design, and Baseline Characteristics of the Study Population

Purpose: A multicentre, randomized, double-blind, placebo-controlled, parallel-group study aimed to define the potential positive effect of dipeptidyl peptidase-4 inhibition on left ventricular systolic function (LVSF) beyond glycemic control in type 2 diabetes mellitus (T2DM) (DYDA 2TM trial). Methods: Individuals with fairly controlled T2DM and asymptomatic impaired LVSF were randomized in a 1:1 ratio to receive for 48 weeks either linagliptin 5 mg daily or placebo, in addition to their stable diabetes therapy. Eligibility criteria were age ≥ 40 years, history of T2DM with a duration of at least 6 months, HbA1c ≤ 8.0% (≤ 64 mmol/mol), no history or clinical signs/symptoms of cardiac disease, evidence at baseline echocardiography of concentric LV geometry (relative wall thickness ≥ 0.42), and impaired LVSF defined as midwall fractional shortening (MFS) ≤ 15%. The primary end-point was the modification from baseline to 48 weeks of MFS. As an exploratory analysis, significant changes in LV global longitudinal strain and global circumferential strain, measured by speckle tracking echocardiography, were also considered. Secondary objectives were changes in diastolic and/or in systolic longitudinal function as measured by tissue Doppler. Results: A total of 188 patients were enrolled. They were predominantly males, mildly obese, with typical insulin-resistance co-morbidities such as hypertension and dyslipidemia. Mean relative wall thickness was 0.51 ± 0.09 and mean MFS 13.3% ± 2.5. Conclusions: DYDA 2 is the first randomized, double-blind, placebo-controlled trial to explore the effect of a dipeptidyl peptidase-4 inhibitor on LVSF in T2DM patients in primary prevention regardless of glycemic control. The main characteristics of the enrolled population are reported