Cassini imaging of Jupiter's atmosphere,satellites, and rings     

Porco CC  West RA  McEwen A  Del Genio AD  Ingersoll AP  Thomas P  Squyres S  Dones L  Murray CD  Johnson TV  Burns JA  Brahic A  Neukum G  Veverka J  Barbara JM  Denk T  Evans M  Ferrier JJ  Geissler P  Helfenstein P  Roatsch T  Throop H  Tiscareno M  Vasavada AR 《Science (New York, N.Y.)》2003,299(5612):1541-1547

The Cassini Imaging Science Subsystem acquired about 26,000 images of the Jupiter system as the spacecraft encountered the giant planet en route to Saturn. We report findings on Jupiter's zonal winds, convective storms, low-latitude upper troposphere, polar stratosphere, and northern aurora. We also describe previously unseen emissions arising from Io and Europa in eclipse, a giant volcanic plume over Io's north pole, disk-resolved images of the satellite Himalia, circumstantial evidence for a causal relation between the satellites Metis and Adrastea and the main jovian ring, and information on the nature of the ring particles.  相似文献   

Analysis of toxic mussels (Mytilus sp.) from the Alaskan Inside Passage     

Y Shimizu  W E Fallon  J C Wekell  D Gerber  E J Gauglitz 《Journal of agricultural and food chemistry》1978,26(4):878-881

  相似文献   

Molecular tritium uptake in Southeastern U.S. soils     

Robert D. Fallon 《Soil biology & biochemistry》1982,14(6):553-556

Molecular tritium deposition occurred in all soils tested. Deposition velocities for tritium ranged from 0.0025 to 0.11cm s^?1 with a geometric mean of 0.028 cm s^?1. Coring surveys from six different sites showed that deposition rates were highest in the upper 20 cm of soil, with little activity evident below this depth. Plant cover did not appear to have a strong direct influence on the profile of tritium deposition activity.  相似文献   

Chromosome loops arising from intrachromosomal tethering of telomeres occur at high frequency in G1 (non-cycling) mitotic cells: Implications for telomere capture     

Daniel A  St Heaps L 《Cell & chromosome》2004,3(1):3

BACKGROUND: To investigate potential mechanisms for telomere capture the spatial arrangement of telomeres and chromosomes was examined in G1 (non-cycling) mitotic cells with diploid or triploid genomes. This was examined firstly by directly labelling the respective short arm (p) and long arm subtelomeres (q) with different fluorophores and probing cell preparations using a number of subtelomere probe pairs, those for chromosomes 1, 3, 4, 5, 6, 7, 9, 10, 12, 17, 18, and 20. In addition some interstitial probes (CEN15, PML and SNRPN on chromosome 15) and whole chromosome paint probes (e.g. WCP12) were jointly hybridised to investigate the co-localization of interphase chromosome domains and tethered subtelomeres. Cells were prepared by omitting exposure to colcemid and hypotonic treatments. RESULTS: In these cells a specific interphase chromosome topology was detected. It was shown that the p and q telomeres of the each chromosome associate frequently (80% pairing) in an intrachromosomal manner, i.e. looped chromosomes with homologues usually widely spaced within the nucleus. This p-q tethering of the telomeres from the one chromosome was observed with large (chromosomes 3, 4, 5), medium sized (6, 7, 9, 10, 12), or small chromosomes (17, 18, 20). When triploid nuclei were probed there were three tetherings of p-q subtelomere signals representing the three widely separated looped chromosome homologues. The separate subtelomere pairings were shown to coincide with separate chromosome domains as defined by the WCP and interstitial probes. The 20% of apparently unpaired subtelomeric signals in diploid nuclei were partially documented to be pairings with the telomeres of other chromosomes. CONCLUSIONS: A topology for telomeres was detected where looped chromosome homologues were present at G1 interphase. These homologues were spatially arranged with respect to one-another independently of other chromosomes, i.e. there was no chromosome order on different sides of the cell nuclei and no segregation into haploid sets was detected. The normal function of this high frequency of intrachromosomal loops is unknown but a potential role is likely in the genesis of telomere captures whether of the intrachromosomal type or between non-homologues. This intrachromosomal tethering of telomeres cannot be related to telomeric or subtelomeric sequences since these are shared in varying degree with other chromosomes. In our view, these intrachromosomal telomeric tetherings with the resulting looped chromosomes arranged in a regular topology must be important to normal cell function since non-cycling cells in G1 are far from quiescent, are in fact metabolically active, and these cells represent the majority status since only a small proportion of cells are normally dividing.  相似文献   

Managing crop damage caused by house mice (Mus domesticus) in Australia     

Shahram KABOODVANDPOUR  Luke K.-P. LEUNG 《Integrative zoology》2010,5(1):2-14

A large-scale outbreak of the house mouse populations occurs in grain growing in Australia on average once every four years. High densities of mice cause major yield losses to cereal crops, and low to moderate densities of mice also cause some losses. Several predictive models based on rainfall patterns have been developed to forecast mouse density. These models carry some uncertainty and the economic value of basing management actions on these models is not clear. Baiting is the most commonly used method and zinc phosphide and other rodenticide bait are effective in reducing up to 90% of mouse populations. Ecologically-based best farming practice for controlling mice has recently been developed on the basis of long-term field studies of mouse populations. No effective biological control method has been developed for mice. However, grain growers still cannot make economically rational decisions to implement control because they do not know the pest threshold density (D_T) above which the economic benefits of control exceed the economic costs of control. Applied predator-prey theory suggests that understanding the relationship between mouse density and damage is the basis for determining D_T. Understanding this relationship is the first research priority for managing mouse damage. The other research priority is to develop a reliable method to estimate unbiased mouse density.  相似文献   

Diseases on Eucalyptus species in Zimbabwean plantations and woodlots     

Luke Jimu  Michael J Wingfield  Eddie Mwenje 《Southern Forests》2015,77(3):221-230

Zimbabwe embarked on planting Eucalyptus species in the early 1900s. Based on a robust breeding programme, it has become a major source of seed for other countries in and outside Africa. Tree health surveys conducted on Eucalyptus in some east and southern African countries over the past two decades have revealed several important fungal diseases that were previously not known in the region, but little is known regarding these problems in Zimbabwe. The aim of this study was to identify important Eucalyptus diseases across Zimbabwe's agroclimatic regions. Morphological characteristics and DNA sequence data were used to identify pathogens collected to species level. Widespread stem canker diseases, caused by species belonging to the Botryosphaeriaceae and Teratosphaeriaceae, and leaf spot diseases caused by fungi in the Capnodiales, were identified. Armillaria root and stem rot was restricted to a single site in the Eastern Highlands. Fungi that could cause canker or blue stain of timber were isolated from recently harvested stumps and included species of Ceratocystis and Ophiostoma. This study is the first to identify Eucalyptus pathogens to species level in Zimbabwe and we report for the first time the presence of the stem canker pathogen T. gauchensis in southern Africa. The results will provide a foundation for the formulation of future disease management strategies in the country.  相似文献   

Comparison of population estimators and indices for monitoring house mice in sorghum crops     

Shahram KABOODVANDPOUR  Carissa FREE  Luke K.-P. LEUNG 《Integrative zoology》2010,5(1):53-62

House mice (Mus musculus domesticus Schwarz & Schwarz, 1943) are monitored in Australia and China to track changes in mouse population densities and forecast their potential damage to cereal crops. The present study compared population indices based on the number of different mice caught and overall trap success from live-trapping with an oil card index (OC) and a tracking index (T) for monitoring mice in sorghum crops immediately before crop maturation. T was measured as the percentage of track board covered with mouse footprints night⁻¹, and OC as the percentage of card removed by mice night⁻¹. The reliability of these abundance indices was quantified by Pearson correlation coefficient with the trappable population size (Ñ), which was estimated by capture–recapture over eight consecutive nights on 175 × 5 trapping grids, in sorghum crops on two properties on the Darling Downs, Queensland. Because of differences among individual mice in capture probability, Model M_h of program MARK was used to account for such heterogeneity and to estimate the size of each mouse population. The number of individual animals caught was more strongly correlated with Ñ than trap success and, therefore, might be a more reliable index; the data suggest that three trapping occasions provide optimal precision for this index. T correlated significantly with Ñ only at sites where the canopy of sorghum plants was closed, and its use should, therefore, be restricted to this habitat. OC did not correlate with Ñ because none or very little of the cards was eaten at low to moderate mouse densities. T and the number of animals caught over three trapping nights are recommended for monitoring mice in sorghum crops immediately prior to crop maturation.  相似文献   

Studies of the Thermal and Haline Influences on Growth and Survival of Litopenaeus vannamei and Litopenaeus setiferus     

Martin Perez‐Velazquez  Mayra L. González‐Félix  D. A. Davis  Luke A. Roy  Xuezhi Zhu 《Journal of the World Aquaculture Society》2013,44(2):229-238

A series of experiments were conducted to examine the effects of salinity (1–48 g/L) on the biological performance, as evaluated by growth and survival, of the Pacific white shrimp, Litopenaeus vannamei, and the Atlantic white shrimp, Litopenaeus setiferus, reared at temperatures of 20, 24 or 28 C. Poor growth and survival of L. vannamei was observed after 21–28 d of culture at low salinity (2 and 4 g/L) at 20 C. Raising salinity to 8 and up to 32 g/L significantly increased survival at this temperature, indicating that avoiding low temperatures is critical for survival of this species when reared at low salinity. A major improvement in the growth rate of L. vannamei was observed at 24 C, but it still was sub‐optimal compared to growth observed at 28 C. Irrespective of salinity, high survival rates were observed at both 24 and 28 C, but variable growth rates were recorded. Contrary to L. vannamei, the Atlantic white shrimp, L. setiferus, which was reared for 28 d at 24 C only, had better growth performance at 8 g/L compared to 2, 16 and 32 g/L. Under equal experimental conditions, L. setiferus had considerably lower weight gain and survival than L. vannamei.  相似文献   

FEMORAL OSTEOMYELITIS AND OSTEOSARCOMA IN A DOG     

Robert T.  Franklin  DVM  Everett  Aronson  DVM  Ron K.  Fallon  DVM  William H.  Fales  PhD  Steve L.  Stockham  DVM  MS  Larry P.  Thornburg  DVM  PhD 《Veterinary radiology & ultrasound》1985,26(6):211-213

An eight-year-old, female, spayed Golden Retriever was referred to the University of Missouri Veterinary Teaching Hospital for a persistent lameness of 9 days duration. The initial diagnosis made by cytology and culture was Clostridium spp osteomyelitis of the right femoral head and neck. After approximately 1 month of treatment with ampicillin, it was noted radiographically that the lesion was progressing. An excision arthroplasty was done. Histological examination of the surgical specimen revealed osteogenic sarcoma. This case documents the importance of bone biopsy in differentiating osteomyelitis from a primary bone tumor.  相似文献   

POSITIVE-CONTRAST ARTHROGRAPHY     

Luke  Muhumuza  B vet med  Joe P.  Morgan  DVM  Vet med dr  Takayoshi  Miyabayashi  DVM  MS  Matthew A. O.  Atilola  DVM  MS 《Veterinary radiology & ultrasound》1988,29(4):157-161

Normal colony Beagle dogs were used to evaluate the effect of concentration, volume, and limb positioning on positive-contrast arthrography in the humeral joint. An 8.4% w/v (33.3 mg/ml ± volume) concentration of analytic grade metrizamide (33 mg/ml of iodine) was thought to provide arthrograms of the highest diagnostic quality. Optimal volume of contrast medium was 2–4 ml in dogs with weight of 7.0–15.6 kg (mean, 10.3 kg). Radiographs thought to be of greatest diagnostic value were those made with the dog in lateral recumbency and the limb positioned for neutral, traction, flexion, supination, and pronation views, plus a caudocranial radiograph made with the dog in dorsal recumbency and the limb in traction.  相似文献