Field measurement of net nitrogen mineralization of manured soil cropped to maize

We evaluated the in situ net nitrogen (N) mineralization in a soil cropped to maize and fertilized for 11 years with cattle slurry or farmyard manure, both common on livestock farms of the Po River valley in Northern Italy. The net N mineralization of the tilled soil layer was measured in six consecutive incubation periods after manure application, for a total of 12 weeks, using the polyethylene buried bags technique. Results showed that net N mineralization was followed by N immobilization and finally, by mineralization whose rate increase until maize flowering. On average, net N mineralization was 70.4 kg N ha⁻¹, with the majority being released during the last measurement period. The time and extent of net N mineralization and plant N uptakes were not affected by fresh manure application. Instead, the effect of past management increased the maximum net N mineralization rate obtained with farmyard manure. The buried bag technique probably underestimates the total amount of mineralized N available for crop growth because it excludes the presence of the plant.     

Recent expansion of Pinus nigra Arn. above the timberline in the central Apennines, Italy

? Context

The altitude of timberlines in the central Apennines has lowered over the past few thousand years due to interacting natural and anthropogenic disturbances. These timberlines are usually sharp and consist of coppiced beech forests.

? Aims

We found scattered individuals of European black pine (Pinus nigra Arn.) at two high elevation sites above the timberline on limestone slopes. We investigated the spatial and temporal pattern expansion of black pine and assessed vigour and growth dynamics of pine trees.

? Methods

Over 250 individuals were mapped in the two sites using GPS. Several site and tree parameters were measured. Tree-ring widths and the frequency of intra-annual density fluctuations were also recorded.

? Results

Black pine expansion started around 30?years ago. Pine trees are randomly distributed at higher elevations with no visible spatial pattern. Germination peaks were synchronous in the two sites, and tree growth displayed very similar chronologies, with synchronous occurrence of intra-annual density fluctuations.

? Conclusion

We hypothesise that the reduced livestock grazing over the last decades as well as climate warming are the major driving forces behind the high-altitude expansion of black pine on the central Apennines, where this species was present in pre-historic times.     

Characterization of enterotoxigenic E. coli (ETEC), Shiga-toxin producing E. coli (STEC) and necrotoxigenic E. coli (NTEC) isolated from diarrhoeic Mediterranean water buffalo calves (Bubalus bubalis)

Two hundred and twenty Escherichia coli isolates from 314 Mediterranean water buffalo calves less than 4 weeks old affected by severe diarrhoea with a lethal outcome were characterized for the presence of the virulence factors LT, ST, Stx1, Stx2, haemolysins, intimin, CNF1, CNF2, CDT-I, CDT-II, CDT-III, CDT-IV, and F17-related fimbriae (F17a, F17b, F17c, F17d). The prevalence of ETEC, STEC and NTEC were 1.8%, 6.8% and 20.9%, respectively. The ETEC isolates were all LT-positive and ST-negative. The STEC isolates were all Stx and intimin-positive, with Stx1 (80%) more frequent than Stx2 (27%). The NTEC isolates were all CNF and Hly-positive, with CNF2 (83%) more frequent than CNF1 (22%). Susceptibility assays to 11 antimicrobials displayed high rates of resistance (>30%) to antimicrobials tested. These data show that the most prevalent strains in diarrhoeic water buffalo calves were NTEC, mostly CNF2 and HlyA-positive, with strong associations CNF2/CDT-III and CNF2/F17c.     

Phenological variability drives the distribution of wildfires in Sardinia

Fuel characteristics play an important role in driving fire ignition and propagation; at the landscape scale fuel availability and flammability are closely related to vegetation phenology. In this view, the NDVI profiles obtained from high temporal resolution satellites, like MODIS, are an effective tool for monitoring the coarse-scale vegetation seasonal timing. The aim of this paper is twofold: our first objective consists in classifying by means of multitemporal NDVI profiles the coarse-scale vegetation of Sardinia into ??phenological clusters?? in which fire incidence is higher (preferred) or lower (avoided) than expected from a random null model. If fires would burn unselectively, then fires would occur randomly across the landscape such that the number of fires in a given phenological cluster would be nearly proportional to the relative area of that land cover type in the analyzed landscape. Actually, certain vegetation types are more fire-prone than others. That is, they are burnt more frequently than others. In this framework, our second objective consists in investigating the temporal parameters of the remotely sensed NDVI profiles that best characterize the observed phenology?Cfire selectivity relationship. The results obtained show a good association between the NDVI temporal profiles and the spatio-temporal wildfire distribution in Sardinia, emphasizing the role of bioclimatic timing in driving fire regime characteristics.     

Ultrafast laser-driven microlens to focus and energy-select mega-electron volt protons

We present a technique for simultaneous focusing and energy selection of high-current, mega-electron volt proton beams with the use of radial, transient electric fields (10(7) to 10(10) volts per meter) triggered on the inner walls of a hollow microcylinder by an intense subpicosecond laser pulse. Because of the transient nature of the focusing fields, the proposed method allows selection of a desired range out of the spectrum of the polyenergetic proton beam. This technique addresses current drawbacks of laser-accelerated proton beams, such as their broad spectrum and divergence at the source.     

Antimutagenic, antioxidant and antimicrobial properties of Maytenus krukovii bark

The hydroalcoholic extract of Maytenus krukovii bark was investigated for its in vitro mutageno-protective activities by means of the Ames Salmonella/microsome assay. The extract showed an inhibitory effect in both T98 and T100 strains against the mutagenic activity of promutagen 2-aminoanthracene but was not protective against directly acting mutagens sodium azide and 2-nitrofluorene. When tested as a radical scavenger and antioxidant it produced a dose-dependent inhibition. The extract did not show significant antibacterial properties, and was weakly active against dermatophyte and phytopathogenic fungi, but inhibited the growth of phytopathogen Pithyum ultimum.     

Intake of specific flavonoids and risk of acute myocardial infarction in Italy

OBJECTIVE: As intake of flavonoids has been associated with reduced risk of coronary heart disease but data on the relation with specific classes of flavonoids are scarce, we assessed the relation between dietary intake of specific classes of flavonoids and the risk of acute myocardial infarction (AMI) in an Italian population.DESIGN: Case-control study. Dietary information was collected by interviewers on a questionnaire tested for validity and reproducibility. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were obtained by multiple logistic regression models including terms for energy and alcohol intake, as well as sociodemographic factors, tobacco and other major recognised risk factors for AMI.SETTING: Milan, Italy, between 1995 and 2003.SUBJECTS: Cases were 760 patients, below age 79 years, with a first episode of non-fatal AMI, and controls were 682 patients admitted to hospital for acute conditions unrelated to diet.RESULTS: A reduced risk of AMI was found for increasing intake of anthocyanidins (OR=0.45, 95% CI 0.26-0.78 for the highest vs. the lowest quintile, Ptrend=0.003) and flavonols (OR=0.65, 95% CI 0.41-1.02, Ptrend=0.02). A tendency towards reduced risks, although not significant, was observed for flavan-3-ols (OR=0.73, 95% CI 0.48-1.10) and total flavonoids (OR=0.74, 95% CI 0.49-1.14). No meaningful heterogeneity was found between the sexes. No association emerged for other flavonoids, including isoflavones, flavanones and flavones.CONCLUSIONS: High intake of anthocyanidins reduced the risk of AMI even after allowance for alcohol, fruit and vegetables, supporting a real inverse association between this class of flavonoids and AMI risk.     

Nitrogen and phosphorous in a loam soil of central Italy as affected by 6 years of different tillage systems

Tillage practices can influence content and dynamics of soil N and P. A field study was conducted on a loam soil (Typic Udifluvent) in Italy, to determine mineral and organic N and P concentrations at the end of 6 years of different tillage systems. Maize (Zea mays L.) was cropped since 1970, and managed since 1994 with deep ploughing (DP) to 40 cm, ripper subsoiling (RS) to 40 cm, shallow ploughing (SP) to 20 cm and minimum tillage with harrow disk (MT) to 10 cm. At the end of the sixth year, soil was collected in 10 cm increments to a total depth of 40 cm. Surface concentration of total N was higher with MT than with RS, SP and DP, but differences disappeared at lower depths. Soil water content was lower under DP and SP treatments than under MT and RS. Residual NO₃-N in the soil profile was not different among tillage treatments. During 6 years, MT increased soil quality, by enrichment of organic N and improvement of soil water content at the surface. Moldboard ploughing was a less sustainable tillage system in this environment.