Transmission parameters of highly pathogenic avian influenza (H7N1) among industrial poultry farms in northern Italy in 1999-2000

We estimated between-farm transmission parameters of the highly pathogenic avian-influenza (HPAI) epidemic that struck the poultry industry of northern Italy (including turkeys, layer hens, broilers, gamebirds, and waterfowl) from December 1999 through April 2000. We estimated the average number of susceptible farms that were infected with HPAI virus by each infectious farm during a day (β) with a generalised linear model (GLM). The HPAI's reproductive ratios (R_h; the average number of new infected farms (IFs) that were caused by an infectious farm) were calculated separately for the regions of Lombardy and Veneto, where 382 out of 413 (92.5%) of IFs were located. In both regions, R_h decreased to 1 during the second month of the epidemic (showing that its containment had been initiated). Subsequently, during the last two months of the epidemic, β and R_h were reduced to 0.04/day and 0.6, respectively, in Veneto and to 0.07/day and 0.8 in Lombardy. The reduction of the susceptible population through strict control measures, including pre-emptive slaughter of at-risk poultry flocks, was implemented to a greatest extent in Veneto and this might have been associated with a more rapid control of the epidemic in this region than in Lombardy.     

Leaf morphology and chemistry in Fagus sylvatica (beech) trees as affected by site factors and ozone: results from CONECOFOR permanent monitoring plots in Italy

During summer 2001, leaf samples were collected from seven beech stands that are part of the Italian network of permanent monitoring plots (CONECOFOR). In each plot, sun leaves from the upper crown were collected from five trees and subjected to chemical analysis (C, N, P, S, K, Ca and Mg) and morphological analysis (area, dry mass, thickness and thickness of individual tissues). Based on the measurements, nutrient ratios (N/C, N/K, N/P, N/Ca, N/Mg, K/Ca, Mg/Ca), sclerophylly indices (leaf mass per area (LMA) and leaf density (LD)) and nitrogen content per leaf area unit (NLA) were determined. Stomatal density was also measured. Among stands, leaf area was smallest and sclerophylly (indicated as LMA) was greatest in the southernmost stands and under drought conditions. Reduced leaf area and increased LMA also appeared to be strongly related to tropospheric ozone concentrations, whereas crown transparency was related mainly to site factors such as rainfall and temperature and, to a lesser extent, ozone concentration. The southernmost stands had a lower N/C ratio than the more northern stands, suggesting that the apoplastic fraction of cells within the leaf played a greater role. In the northern stands (especially at Lombardy and in Piedmont) where ozone concentrations were high, nutrient ratios were unbalanced and the high value of LMA appeared to be related primarily to the contribution of plasmatic components. Overall, leaf morphology was most sensitive to climate stress at the southern plots and to environmental pollution (nitrogen deposition and tropospheric ozone concentration) at some of the northern plots.     

Quantitative 23Na magnetic resonance imaging of model foods

Partial (23)Na MRI invisibility in muscle foods is often referred to as an inherent drawback of the MRI technique, impairing quantitative sodium analysis. Several model samples were designed to simulate muscle foods with a broad variation in protein, fat, moisture, and salt content. (23)Na spin-echo MRI and a recently developed (23)Na SPRITE MRI approach were compared for quantitative sodium imaging, demonstrating the possibility of accurate quantitative (23)Na MRI by the latter method. Good correlations with chemically determined standards were also obtained from bulk (23)Na free induction decay (FID) and CPMG relaxation experiments on the same sample set, indicating their potential use for rapid bulk NaCl measurements. Thus, the sodium MRI invisibility is a methodological problem that can easily be circumvented by using the SPRITE MRI technique.