Zwei von Uganda nach Hawaii importierteOpius-Arten(Hymenoptera,Braconidae)

Ohne Zusammenfassung     

Earth-Based Observations of the Galileo Probe Entry Site

Earth-based observations of Jupiter indicate that the Galileo probe probably entered Jupiter's atmosphere just inside a region that has less cloud cover and drier conditions than more than 99 percent of the rest of the planet. The visual appearance of the clouds at the site was generally dark at longer wavelengths. The tropospheric and stratospheric temperature fields have a strong longitudinal wave structure that is expected to manifest itself in the vertical temperature profile.     

N'-nitrosonornicotine in tobacco

N'-Nitrosonornicotine, a potential carcinogen, has been positively identified in unburned tobacco. The amount in commercial U.S. tobacco products is between 1.9 to 88.6 parts per million, one of the highest values of an environmental nitrosamine yet reported. The amount in food and drink rarely exceeds 0.1 part per million. This compound is the first example of a potential organic carcinogen isolated from tobacco.     

Experimental evidence for spatial self-organization and its emergent effects in mussel bed ecosystems

Spatial self-organization is the main theoretical explanation for the global occurrence of regular or otherwise coherent spatial patterns in ecosystems. Using mussel beds as a model ecosystem, we provide an experimental demonstration of spatial self-organization. Under homogeneous laboratory conditions, mussels developed regular patterns, similar to those in the field. An individual-based model derived from our experiments showed that interactions between individuals explained the observed patterns. Furthermore, a field study showed that pattern formation affected ecosystem-level processes in terms of improved growth and resistance to wave action. Our results imply that spatial self-organization is an important determinant of the structure and functioning of ecosystems, and it needs to be considered in their conservation.     

Failure to confirm XMRV/MLVs in the blood of patients with chronic fatigue syndrome: a multi-laboratory study

Murine leukemia viruses (MLVs), including xenotropic-MLV-related virus (XMRV), have been controversially linked to chronic fatigue syndrome (CFS). To explore this issue in greater depth, we compiled coded replicate samples of blood from 15 subjects previously reported to be XMRV/MLV-positive (14 with CFS) and from 15 healthy donors previously determined to be negative for the viruses. These samples were distributed in a blinded fashion to nine laboratories, which performed assays designed to detect XMRV/MLV nucleic acid, virus replication, and antibody. Only two laboratories reported evidence of XMRV/MLVs; however, replicate sample results showed disagreement, and reactivity was similar among CFS subjects and negative controls. These results indicate that current assays do not reproducibly detect XMRV/MLV in blood samples and that blood donor screening is not warranted.     

Self-organized patchiness and catastrophic shifts in ecosystems

Unexpected sudden catastrophic shifts may occur in ecosystems, with concomitant losses or gains of ecological and economic resources. Such shifts have been theoretically attributed to positive feedback and bistability of ecosystem states. However, verifications and predictive power with respect to catastrophic responses to a changing environment are lacking for spatially extensive ecosystems. This situation impedes management and recovery strategies for such ecosystems. Here, we review recent studies on various ecosystems that link self-organized patchiness to catastrophic shifts between ecosystem states.     

Identification of hydroxymethanesulfonate in fog water

Previous studies have suggested that hydroxymethanesulfonate ion (HMSA) can be an important species in fog and cloud water. Formation of HMSA explains observed excesses of sulfur in the S(IV) state (+4 oxidation state) and formaldehyde (CH(2)O) in fogs and clouds. HMSA was determined in fog water by a novel ion-pairing chromatographic technique. Concentrations in samples collected in Bakersfield, California, within 5 kilometers of major sources of sulfur dioxide (SO(2)), were as high as 300 micromoles per liter. Total CH(2)O and S(IV) concentrations, which were measured independently, ranged from 10 to 200 and 5 to more than 300 micromoles per liter, respectively. Concentrations of CH(2)O, S(IV), and HMSA at Buttonwillow, California, which is 15 kilometers from the nearest source of SO(2), were less than those at Bakersfield but not absent. These data confirm that HMSA forms in atmospheric water droplets and can reach appreciable concentrations. HMSA represents an important source of acidity for water droplets and may also play a role in long-distance transport and transformation of SO(2).     

Inheritance of functional foreign genes in plants

Morphologically normal plants were regenerated from Nicotiana plumbaginifolia cells transformed with an Agrobacterium tumefaciens strain containing a tumor-inducing plasmid with a chimeric gene for kanamycin resistance. The presence of the chimeric gene in regenerated plants was demonstrated by Southern hybridization analysis, and its expression in plant tissues was confirmed by the ability of leaf segments to form callus on media containing kanamycin at concentrations that were normally inhibitory. Progeny derived from several transformed plants inherited the foreign gene in a Mendelian manner.     

Values and policy conflict in West German agriculture

Family farming became a major social force in the Federal Republic following World War II. Several political, economic and social factors facilitated the development of a unified political representation within the farm sector. The German Farmers Union (Deutscher Bauernverband) became the main representative of the farm sector. Its platform included the preservation of family farms and it attempted to realize this goal through the promotion of commodity price support policies. Political support for these programs was legitimized with the elaboration of a system of values espousing the positive qualities of family farms. Price support policies were opposed by free market advocates with an alternative system of values that fundamentally contradicted those of family farm advocates. Although commodity price supports promoted by partisans of family farming dominated agricultural policy formation in the 1950s and 1960s, fiscal crisis in the EEC and economic differentation within the farm sector began to undermine the position of family farming as a social force. But economic stagnation also prevented the free market position from gaining dominance. Economic differentiation within the farm sector has had an important regional dimension, and this has served as a basis for policy compromise. Economic changes over the post-WWII period have undermined the family farm as a social force. Nevertheless, values associated with family farming continue to have a place in agricultural policy. However, family farming is valued less as an end in itself, and more as a means to the realization of more practical ends such as the preservation of rural landscapes for recreational purposes.