Some difficulties of ecological thinking,considered from a critical systems perspective: A plea for critical holism

We probably have simplified matters too much. We tend to talk about systems thinking and practice as if we knew what they are. The fashionable call for “holistic” or “systems” thinking in ecological issues provides a major example. This much is certain: the quest for comprehensiveness, although it represents an epistemologically necessary idea, is not realizable. If we assume that it is realizable, the critical idea underlying the quest will be perverted into its opposite, i.e., into a false pretension to superior knowledge and understanding—a danger of which the environmental movement does not always appear to be sufficiently aware. My question, therefore, is this: How can we deal critically with the fact that our thinking, and hence our knowledge, designs, and actions, cannot possibly be comprehensive, in the sense that we never “comprehend” all that ought to be understood before we pass to judgment and action? What consequences does this fact imply for a critical systems approach to ecological concerns and, ultimately, for our concepts of rationality in general?     

Zur Diskussion über die Homogenität des Erdinnern

Summary According to considerations put forwards byW. Kuhn andA. Rittmann some years ago, it follows that the chemical composition of the interior of the earth must be rather homogeneous; the well-known discontinuity which occurs at 2900 km with respect to the propagation of longitudinal and transverse waves should not be due to a discontinuity of the material composition (not to an iron core). It is due to a continous decrease of the viscosity and thereby of the relaxation time; transverse waves of a period of e.g. 30 seconds will no more be propagated in a material whose relaxation time for tangential stress is below 30 seconds, while the longitudinal waves will suffer a decrease of the velocity at the same time.A criticism put forward byA. Eucken consists in the argument that a material in which the time of relaxation for tangential stress becomes equal to the period of the vibration will exhibit a considerable absorption coefficient for longitudinal waves too. It is now shown that the distance on which the period of vibration and the relaxation time are approximately equal is small compared with the wave length of the seismic waves in question, from which it follows that the resulting absorption of the longitudinal waves too will only be small.A further consideration shows that a mixture of 99 atomic % hydrogen and 1 atomic % of iron is most probably supercritical at a temperature of 5000° abs.A survey of the solubilities in question shows further that the hydrogen present in a mixture of 90% hydrogen and 10% iron should on the strength of the absorption coefficient be completely absorbed by the iron at 5000° abs. and at a total pressure of 2.10⁶ atmospheres.The main argument why the assumption of an iron core inside the earth must be dismissed remains the fact that the present state must be the result of an asymptotic processus which at least in its final phase has occurred under conditions similar to the present conditions of temperature, pressure and viscosity; these latter conditions are far from permitting the processus of sedimentation etc. which would be required.     

Evaluation of oral vaccination against mouse-typhoid in a new animal model

Summary In a simple, new animal model the spread of mouse-typhoid within a mouse-colony was studied and oral vaccination against this disease was evaluated. Live vaccine was superior to inactivated vaccine.     

Identification of a cold receptor reveals a general role for TRP channels in thermosensation

The cellular and molecular mechanisms that enable us to sense cold are not well understood. Insights into this process have come from the use of pharmacological agents, such as menthol, that elicit a cooling sensation. Here we have characterized and cloned a menthol receptor from trigeminal sensory neurons that is also activated by thermal stimuli in the cool to cold range. This cold- and menthol-sensitive receptor, CMR1, is a member of the TRP family of excitatory ion channels, and we propose that it functions as a transducer of cold stimuli in the somatosensory system. These findings, together with our previous identification of the heat-sensitive channels VR1 and VRL-1, demonstrate that TRP channels detect temperatures over a wide range and are the principal sensors of thermal stimuli in the mammalian peripheral nervous system.     

Immunostimulating and adjuvant activities of a low molecular weight lipopeptide]

From crude extracts of a Streptomyces strain exhibiting immunopotentiating effects, a tetrapeptide was isolated and its structure established as L Ala leads to D isoGlu leads to L, L Dap comes from Gly. This peptide was devoid of biological activity but its chemical coupling with lauric acid gave a substance endowed with adjuvant and immunostimulating properties. This substance and the corresponding synthetic lauroyltetrapeptide were as active in this respect as the muramyl-dipeptide, thus far considered as the minimal adjuvant-active structure of bacterial cell walls: the presence of a sugar moiety is therefore not a prerequisite for immunopotentiating activities.     

Suppression and enhancement of humoral immune response to Toxoplasma gondii by passive antibody

Anti-toxoplasma antibodies administered passively to mice may lead to suppression of enhancement (reported for the first time with Protozoan parasites) of subsequent antibody response when these animals are later infected with Toxoplasma gondii. The outcome is dependent on infecting strain of Toxoplasma and the antigen-antibody ratio.     

The effect of BCG-vaccination on vaccinia virus infections in mice

Summary Pretreatment with BCG yielded a high degree of protection against experimental vaccinia virus infections in mice.Corynebacterium parvum andAristolochia acid were less protective; other immunostimulants were ineffective.