Iodine-129/xenon-129 age of magnetite from the orgueil meteorite

Magnetite from the Orgueil C1 chondrite is only 2.0 +/- 2.4 million years older by the iodine-xenon method than the next oldest meteorite, the Karoonda C4 chondrite. This age ties the primitive C1 chondrites to the extensive iodine-xenon chronology of normal chrondrites. If Karoonda and Orgueil magnetite formed from similar material, then the age difference is an upper limit to the formation time of these meteorites-and by customary extension, the solar system. Condensation, chondrule formation, accretion, and metamorphism of the Karoonda parent body all seem to have been completed within a few million years.     

Damage by rats Rattus norvegicus to breeding birds on Danish islands

Occurrence of rats Rattus norvegicus was recorded in Danish islands during the period 1970–1979. Rats apparently became common during the 1960s and 1970s. Their frequency fluctuated, indicating a possible 4-year cycle. Most rat colonisations lasted a single year. Geographical differences in their frequency may be caused by regional differences in distribution of larid colonies. Rat distribution did not follow the pattern suggested by the theory of island biogeography; presence of larids may be of major importance. When rat populations in hedges, ponds and streams are at maximum population density in autumn, pregnant females emigrate to, and so colonise, islands. Flooding and the severity of the winter may cause extinction. Food supply and predation may be of importance in limiting rat numbers. Breeding birds suffer, especially those placing their nests near rat runs; rat predation on adults may have serious consequences for a long-lived species, whereas that on eggs and young is insignificant. Some larid species renest in the immediate vicinity when predated by rats; others desert their dense colonies. Rat control is successful in small islands, whereas large island populations are only exterminated with difficulty. They should be controlled to prevent predation and to keep breeding grounds usable. This should be done in late winter when population density is low and food-supply insufficient.     

Comparison of parasite-specific immunoglobulin levels in two chicken lines during sustained infection with Ascaridia galli

Increasingly large numbers of poultry are held in production systems with access to outdoor areas. In these systems intestinal helminths are found with flock prevalences of up to 100%. Helminth infections influence chicken health negatively, which is why the following investigation has been performed.In the present experiment, 20 chickens of two inbred chicken lines containing the major histocompatibility complex (MHC) haplotypes, B14 and R5, were inoculated with 500 embryonated Ascaridia galli eggs. The A. galli-specific IgG titres of serum samples and the excretion of A. galli eggs in chicken faeces were measured for a period of 81 weeks.The level of excreted A. galli eggs measured as eggs per gram chicken faeces (EPG) varied greatly between chickens in each line. Significant differences were found between the two lines and with the R5 chickens reaching the highest levels. Likewise, the A. galli-specific IgG titres in serum differed significantly between the two lines, and an inverse relationship between infection level (EPG) and antibody titres was found. Although this inverse relationship suggests that humoral immunity may be involved in protection against A. galli infection, the high antibody titres did not prevent continued infection.     

Analysis of auditory and neurologic effects associated with ventral bulla osteotomy for removal of inflammatory polyps or nasopharyngeal masses in cats

OBJECTIVE: To determine whether cats undergoing ventral bulla osteotomy (VBO) for removal of inflammatory polyps or nasopharyngeal masses have altered ability to hear and whether polyp or mass removal affects auditory function as measured via air-conducted brainstem auditory evoked response (BAER). DESIGN: Prospective case series. ANIMALS: 21 cats. PROCEDURES: Cats were sedated and had otic-oral examinations to confirm presence of nasopharyngeal masses; BAER testing was done immediately prior to and following the completion of a VBO and polyp or mass removal. Recheck examination, including otic examination and BAER in sedated cats, was performed when possible. Results-17 cats met final inclusion criteria, and long-term follow-up was available for 15. Six of 17 had deafness as measured via air-conducted BAER prior to surgery. Mean followup time was 161 days, and there was no change from presurgical status in auditory ability in any cat. Eleven of 17 developed ipsilateral Horner syndrome in the immediate postoperative period, and 1 of 16 had polyp regrowth. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that in cats, VBO for removal of inflammatory polyps or masses is unlikely to affect hearing as measured via air-conducted BAER. Most cats developed short-term Horner syndrome. Cats with deafness prior to surgery did not regain auditory function. Ventral bulla osteotomy to remove nasopharyngeal polyps or masses provided no functional advantage with regard to restoration of hearing, compared with other surgical techniques. Polyp recurrence and long-term adverse effects were uncommon.     

The use of profile diagrams for mixed stands in urban woodlands—the management perspective

In the emerging paradigm of urban forestry objectives are often to develop mixed stands with complex structures. Such stands cannot easily be described in words and numbers. A logical alternative would seem to describe the structure of such mixed stands by use of image-based management tools. However implementing new management goals and using image-based tools challenges professionals, educated and trained within the age-class forestry tradition, to use their knowledge in a creative way. This paper describes how professionals contextualise from hand drawn profile diagrams when planning the management of mixed stands. The appropriateness of profile diagrams in this context is further discussed. The study was carried out as a case study focusing on the planning and development of long-term management goals for two young mixed stands for recreational use. We used explorative, in-depth interviews to identify the perspective on profile diagrams, as experienced by five individuals with different academic backgrounds as well as years of experience. The interviewees revealed that personal experiences and mental images played a key role in order to display an intuitive understanding of the subject stands through the profile diagrams. Further, they recognised this approach themselves often referring to other stands to make comparisons. The types of references used could be divided into three distinct categories: specific, generic and metaphoric. With regard to the ongoing move from age-class forestry to multifunctional management of mixed stands, this aid to dialogue might be the most relevant way in which profile diagrams can contribute to the implementation of new management paradigms.     

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CEREBRAL VENTRICULAR SIZE IN DEVELOPING NORMAL KITTENS MEASURED BY ULTRASONOGRAPHY

To evaluate the age of fontanelle closure of normal kittens and the size of their lateral ventricles, 50 ultrasonographic examinations using the bregmatic fontanelle as an acoustic window were made. Seven kittens, laboratory animals, were included in the study. To verify the location of the lateral ventricle, two of the kittens were sacrificed as neonates. In one of them ink was injected prior to autopsy into one lateral ventricle under sonographic guidance. In a longitudinal study of five of the kittens, the skull depth and the depth of the central part of the lateral ventricle reproduced in a longitudinal view could be measured up to the age of about 5 months. During that period, the skull depth increased from a median value of 1.95 cm (1.92-1.98) in a seven-day-old cat to 2.58 cm (2.52-2.59) in a 154-day-old cat, while the afore-mentioned ventricle values increased from 0.3 mm to 1.1 mm.     

Interstellar carbon in meteorites

The Murchison and Allende chondrites contain up to 5 parts per million carbon that is enriched in carbon-13 by up to + 1100 per mil (the ratio of carbon-12 to carbon-13 is approximately 42, compared to 88 to 93 for terrestrial carbon). This "heavy" carbon is associated with neon-22 and with anomalous krypton and xenon showing the signature of the s-process (neutron capture on a slow time scale). It apparently represents interstellar grains ejected from late-type stars. A second anomalous xenon component ("CCFXe") is associated with a distinctive, light carbon (depleted in carbon-13 by 38 per mil), which, however, falls within the terrestrial range and hence may be of either local or exotic origin.     

Effects of elevated atmospheric CO2, prolonged summer drought and temperature increase on N2O and CH4 fluxes in a temperate heathland

In temperate regions, climate change is predicted to increase annual mean temperature and intensify the duration and frequency of summer droughts, which together with elevated atmospheric carbon dioxide (CO₂) concentrations, may affect the exchange of nitrous oxide (N₂O) and methane (CH₄) between terrestrial ecosystems and the atmosphere. We report results from the CLIMAITE experiment, where the effects of these three climate change parameters were investigated solely and in all combinations in a temperate heathland. Field measurements of N₂O and CH₄ fluxes took place 1-2 years after the climate change manipulations were initiated. The soil was generally a net sink for atmospheric CH₄. Elevated temperature (T) increased the CH₄ uptake by on average 10 μg C m⁻² h⁻¹, corresponding to a rise in the uptake rate of about 20%. However, during winter elevated CO₂ (CO₂) reduced the CH₄ uptake, which outweighed the positive effect of warming when analyzed across the study period. Emissions of N₂O were generally low (<10 μg N m⁻² h⁻¹). As single experimental factors, elevated CO₂, temperature and summer drought (D) had no major effect on the N₂O fluxes, but the combination of CO₂ and warming (TCO₂) stimulated N₂O emission, whereas the N₂O emission ceased when CO₂ was combined with drought (DCO₂). We suggest that these N₂O responses are related to increased rhizodeposition under elevated CO₂ combined with increased and reduced nitrogen turnover rates caused by warming and drought, respectively. The N₂O flux in the multifactor treatment TDCO₂ was not different from the ambient control treatment. Overall, our study suggests that in the future, CH₄ uptake may increase slightly, while N₂O emission will remain unchanged in temperate ecosystems on well-aerated soils. However, we propose that continued exposure to altered climate could potentially change the greenhouse gas flux pattern in the investigated heathland.