Continuous biogas production from fodder beet silage as sole substrate.

Since April 2000 a two-step anaerobic plant with two subsequent 500 m3 reactors has been producing biogas from fodder beet silage (pH 3.4-4.1) as the sole substrate. The plant is located at Kirchlengern near Bielefeld, Germany. Initially the reactors were inoculated with swine manure at 37 degrees C. After a start-up phase the process was sustained at pH 7.5-8.0 by feeding the silage as sole substrate with an HRT of about 55 d twice a day. Parallel to the biogas plant at Kirchlengern four one-step laboratory reactors were continuously driven at temperatures of 37 degrees C, 45 degrees C, 60 degrees C and 65 degrees C. They were fed with the same silage, but only once per day (one impulse). The organic loading rate (OLR) was adjusted to 3.9 g volatile solids (VS)/(l*d) with a concomitant hydraulic retention time (HRT) of 27 d. There was no problem with starting the reactors, but after 86 days the volumetric gas production of the 65 degrees C reactor ceased and a high amount of approximately 65 mM propionate could be determined. By decreasing the temperature down to 60 degrees C a stable reactor performance was recovered for a period of at least 600 further days. Interestingly microscopic analyses revealed that the morphology of methanogenic bacteria in the 60 degrees C was quite different from the 37 and 45 degrees C reactor exhibiting only rodlike methanogens whereas at 37 degrees C coccoid morphotypes besides rodlike methanogens were dominant. In a 55 degrees C reactor (separate experiment) a mixture of coccoid and rodlike methanogens established. During impulse feeding with 3.9 g (VS)/(l*d) it was observed that the quickest recovery of gas production, the pH, CH4 and CO2 content as well as the redox value could be observed at 37 degrees C or at 45 degrees C. Recovery of 75% gas volume (related to the value before or after impulse feeding) was obtained after 5.5 and 7.5 h of feeding time point whereas the 60 degrees C reactor needed 16 h. Slight significant differences were seen in the spectrum of volatile fatty acids (VFA) reaching at 37 degrees or 45 degrees C its maximum with 10-30 mM total VFA at 2-3 h after feeding. After this the VFA level declined to nearly zero (except for the 60 degrees C reactor). Therefore the 37 degrees C reactor was favoured. A double experiment with a second 37 degrees C reactor was started by a somewhat different inoculation procedure from the remaining 3 reactors, but revealed similar results. An impulse feeding experiment with a very high OLR of 16.5 g (VS)/(l*d) lasting 1 week offered a stable reactor performance with a peak GPR of up to 24 l/(l reactor *d) and an HRT of 5.45d. Therefore a long term operation with an HRT of only 7.5 days and an OLR of 12 g (VS)/(l*d) should be possible. By increasing the temperature no significantly different specific gas production rates and methane yields could be observed, e.g. it gave 600-7001 biogas from 1 kg VS. The corresponding methane content ranged between 62-64%. With a methane content of 63 +/- 1% a yield of 40.1 +/- 2 m3 methane/ton fresh fodder beet silage was obtained.

Influence of user-defined parameters on diffusion tensor tractography of the corticospinal tract.

This study discusses the influence of user-defined parameters on fiber tracking results obtained from a standard deterministic streamline tractography algorithm. Diffusion tensor imaging with fiber tractography was performed in five healthy volunteers. A region of interest was highlighted in the ventral part of the pons at the level of the middle cerebellar peduncle. The parameters studied were angle threshold, fractional anisotropy threshold, step length and number of seed samples per voxel. Changes in fiber tracts were described for increasing values per parameter. Increasing the angle threshold resulted in more and longer fibers. A higher fractional anisotropy threshold resulted in decreased length and fiber tracts that were not representative. Increasing the step length decreased the fiber continuity and altered its position. A higher number of seed samples per voxel resulted in a higher fiber tract density. When interpreting diffusion tensor images, the reader should understand the influence of user-defined settings on the results, and should be aware of the inter-dependency of fiber tracking parameters.

[The role of sports in preparation for an active age (author's transl)]. / Die Rolle des Sports bei der Vorbereitung auf ein aktives Alter.

The starting hypothesis is aimed at the retarding effect of sporting activities on ageing. Sport just improve those abilities, which are reduced with ageing, for instance the motoric-dynamic mobilities. The effect of sport can also be identified at the heart-circuit-respiration-system. Staying power training is desired for preventive effectiveness. Psychic functions are influenced and models of behaviour are formed by sport. Individual motivations must be used stronger and barriers must be destroyed to increase the general efficaciousness of sports in old age. Sport in old age is not identical with sport of pensioners, the health training should already start in the fourties and continued up to the end of the life. Concerning the organisation and fitness of the persons the lawfulness has to be considered.

[The age distribution of occupational disease (author's transl)]. / Aussagen über den Altersgang der Berufskrankheiten.

The author analyses the incidence of occupational diseases in 1979 and their distribution according to age. Almost two thirds of all occupational diseases are detected in the latter half of life. The fact that noise-induced defective hearing, degenerative changes in the locomotor system, silicosis, asbestosis, and cancer of the airways due to occupational factors occur late in life cannot be primarily attributed to the physiological process of ageing. Rather, the reason for the late manifestation of these occupational diseases is the long time of exposure needed for symptoms to appear. Like other pathological forms of ageing, the consequences of exposure to occupational hazards must be distinguished from physiological processes of ageing. Normal ageing presupposes health-promoting working and living conditions.

Criteria for the dispensary care of elder workers.

The dispensary attendance of old people in the production process is deduced as the means and necessities of a purposive medical, social and cultural care. The dispensary attendance is the highest step of the socialist health protection and reflects its prophylactic fundamental trend. It was the object of our activities to specify the criteria of the dispensary attendance to elder workers, which we designate as gerodispensary attendance in order to furnish the pre-conditions that both effort and efficiency can be adequately proportioned for the benefit of elder workers.

[The artist in the 2d half of his professional life]. / Der Künstler in der zweiten Hälfte seines Arbeitslebens.

The authors apply the basic conceptions of gero-hygiene to the care of artists. As to the dispensaire care of artists, the particular correlations between professional activity, health, and age are referred to. The highly specialized professional training and qualification for these professions, as well as all occupationally induced injuries occurring, above all, occupational diseases of performing artists of orchestra musicians, and further artistic groups of activities, require a specific preparation for age.

[Systematic industrial medical observation and care of ageing working people as a means of preparing for retirement age (author's transl)]. / Arbeitsmedizinische Dispensairebetreuung älterer Werktätiger als Mittel der Vorbereitung auf das Rentenalter

The elucidations start out from the "Principles for the continued improvement of medical care of the aged" published in the "Verfüngungen und Mitteilungen des Ministeriums für Gesundheitswesen" in March 1971. A study was made in which people approaching retirement age and people already retired were interviewed and examined according to a set system. These people were then given systematic geriatric observation and care. A catalogue of conditions based on the survey was drawn up. It appears that the main task is to introduce legislation giving people approaching retirement age reasonable working hours adjusted to their diminished working capacity. Such a measure is called for due to the scientifically confirmed fact that elderly people require rehabilitative treatment for which reason they should be given extra time off. Very positive results have been achieved with recreation holidays in the form of prophylactic cures in interprise-owned facilities. There is no reason why people approaching retirement age and those already retired should not be prescribed cures. Paragraph 95 of the Labour Code provides the basis for shortening the daily hours of work intermittently, for introducing temporary single-shift work or for changing over from piece-work to time-wages. Temporary assignment of lighter work can also be arranged. The importance of systematic job analyses and of creating conditions for proper health education and sports for ageing people is emphasized. Industrial medicine reports stress that the advanced age groups should not continue to be neglected. Finally the study states that preparatory measures with regard to changes of places of work of factory workers should be carried out with great care; such measures should be taken already between the ages of 45 and 55.