Research Note: Comparison of two methods to measure broiler tibia morphology

The skeletal integrity of chickens is an important area of research and detailed measures are needed to better understand the influence of experimental manipulation on bone health. The objective of this experiment was to compare 2 methods to measure the superficial tibiotarsus (tibia) morphology of broiler chickens collected in the wet laboratory (WL) or from digital images (DIG). The length, width at 90%, 75%, 50%, 25%, and 10% of the length, proximal and distal head width, medial, lateral, and distal intercondylar groove depth (ID), and proximal head angle were measured on the right and left tibias collected from broilers in 2 experiments (E1, E2). In both experiments, tibias had a greater width at 90% of the length when measured with the WL method compared with the DIG method (P ≤ 0.04), while tibias measured with the DIG method had a greater length, distal ID, and widths at 10%, 25%, 50%, and 75%, of the length compared with the WL method (P < 0.0001). In E1, tibias measured with the DIG method had a greater medial, lateral, and distal ID compared with the WL method (P ≤ 0.04). In E2, compared with the DIG method, tibias measured with the WL method had a greater distal head width and lateral ID, yet a shallower distal ID (P ≤ 0.03). The use of the DIG method provided more precise measures but, due to the limitations of measures from digital images and the opportunity for more accurate measures to be collected with the WL method, the WL method is recommended to measure the superficial morphology of broiler chickens because it was more accessible and practical.

Nucleation particles in diesel exhaust: composition inferred from in situ mass spectrometric analysis

Mass spectrometric measurements of size and composition of diesel exhaust particles have been performed under various conditions: chassis dynamometer tests, field measurements near a German motorway, and individual car chasing. Nucleation particles consisting of volatile sulfate and organic material could be detected both at the chassis dynamometer test facility and during individual car chasing. We found evidence that if nucleation occurs, sulfuric acid/water is the nucleating agent. Low-volatile organics species condense only on the preexisting sulfuric acid/water clusters. Nucleation was found to depend strongly on various parameters such as exhaust dilution conditions, fuel sulfur content, and engine load. The latter determines the fraction of the fuel sulfur that is converted to sulfuric acid. The organic compounds (volatile and low-volatile) condense only on preexisting particles, such as both sulfuric acid nucleation particles and larger accumulation mode soot particles. On the latter, sulfuric acid also condenses, if the conditions for nucleation are not given. The overall ratio of sulfate to organic (volatile and low-volatile) is also strongly dependent on the engine load. It was found that the production of nucleation particles even at high engine load can be suppressed by using low-sulfur fuel.

[Determinants of the decision to retire. A contribution to the discussion on the "flexible retirement age limit" (author's transl)]

Our research intended to analyse the effects of the "Flexible Altersgrenze" (introduced in 1973) on the position of older workers. The study was designed as a casestudy in three firms of different branches of industry. We found out that all older workers planned to make use of the "Flexible Altersgrenze" in as far as their income and insurance claims permitted it. Under this scheme the retirement age would still be higher than most of the workers would prefer. The following stipulations infludenced the decision to retire: -- the state of physical health -- the strain of working-conditions in their present job and throughout their working-life -- a pessimistic view of their job prospects at that age -- unfavourable experiences with the effects of technical and organisational change in working-conditions -- the necessity of changing the job in later life because of the incapability to bear its strain.