Academic freedom. Thai science agency clamps down on sensitive research     

Stone R 《Science (New York, N.Y.)》2007,318(5856):1537-1538

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Aquatic ecology. On life support     

Stone R 《Science (New York, N.Y.)》2007,316(5832):1688

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Energetic charged particles in the magnetosphere of neptune     

Stone EC  Cummings AC  Loooper MD  Selesnick RS  Lal N  McDonald FB  Trainor JH  Chenette DL 《Science (New York, N.Y.)》1989,246(4936):1489-1494

The Voyager 2 cosmic ray system (CRS) measured significant fluxes of energetic [>/=1 megaelectron volt (MeV)] trapped electrons and protons in the magnetosphere of Neptune. The intensities are maximum near a magnetic L shell of 7, decreasing closer to the planet because of absorption by satellites and rings. In the region of the inner satellites of Neptune, the radiation belts have a complicated structure, which provides some constraints on the magnetic field geometry of the inner magnetosphere. Electron phase-space densities have a positive radial gradient, indicating that they diffuse inward from a source in the outer magnetosphere. Electron spectra from 1 to 5 MeV are generally well represented by power laws with indices near 6, which harden in the region of peak flux to power law indices of 4 to 5. Protons have significantly lower fluxes than electrons throughout the magnetosphere, with large anisotropies due to radial intensity gradients. The radiation belts resemble those of Uranus to the extent allowed by the different locations of the satellites, which limit the flux at each planet.  相似文献   

Radioastronomy of the sun: solar radiophysics     

Stone RG 《Science (New York, N.Y.)》1987,235(4790):800a

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Monodisperse double emulsions generated from a microcapillary device     

Utada AS  Lorenceau E  Link DR  Kaplan PD  Stone HA  Weitz DA 《Science (New York, N.Y.)》2005,308(5721):537-541

Double emulsions are highly structured fluids consisting of emulsion drops that contain smaller droplets inside. Although double emulsions are potentially of commercial value, traditional fabrication by means of two emulsification steps leads to very ill-controlled structuring. Using a microcapillary device, we fabricated double emulsions that contained a single internal droplet in a core-shell geometry. We show that the droplet size can be quantitatively predicted from the flow profiles of the fluids. The double emulsions were used to generate encapsulation structures by manipulating the properties of the fluid that makes up the shell. The high degree of control afforded by this method and the completely separate fluid streams make this a flexible and promising technique.  相似文献   

Nonproliferation. North Korea's nuclear shell game     

Stone R 《Science (New York, N.Y.)》2004,303(5657):452-454

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Beta-adrenergic receptor kinase: primary structure delineates a multigene family   总被引：25，自引：0，他引：25  

J L Benovic  A DeBlasi  W C Stone  M G Caron  R J Lefkowitz 《Science (New York, N.Y.)》1989,246(4927):235-240

The beta-adrenergic receptor kinase (beta-ARK), which specifically phosphorylates only the agonist-occupied form of the beta-adrenergic and closely related receptors, appears to be important in mediating rapid agonist-specific (homologous) desensitization. The structure of this enzyme was elucidated by isolating clones from a bovine brain complementary DNA library through the use of oligonucleotide probes derived from partial amino acid sequence. The beta-ARK cDNA codes for a protein of 689 amino acids (79.7 kilodaltons) with a protein kinase catalytic domain that bears greatest sequence similarity to protein kinase C and the cyclic adenosine monophosphate (cyclic AMP)--dependent protein kinase. When this clone was inserted into a mammalian expression vector and transfected into COS-7 cells, a protein that specifically phosphorylated the agonist-occupied form of the beta 2-adrenergic receptor and phosphorylated, much more weakly, the light-bleached form of rhodopsin was expressed. RNA blot analysis revealed a messenger RNA of four kilobases with highest amounts in brain and spleen. Genomic DNA blot analysis also suggests that beta-ARK may be the first sequenced member of a multigene family of receptor kinases.  相似文献   

Dynamic relationships between soil properties and foliar disease as affected by annual additions of organic amendment to a sandy-soil vegetable production system     

Dorith Rotenberg  Leslie Cooperband  Alexandra Stone 《Soil biology & biochemistry》2005,37(7):1343-1357

Additions of organic amendments to agricultural soils can lead to improved soil quality and reduced severity of crop diseases. However, the relationship between disease severity and soil properties as affected by repeated additions of these amendments is poorly understood. The primary objectives of this study were to (i) resolve multivariate relationships between soil properties and foliar disease severity and (ii) identify soil properties that contribute to disease severity in an intensive irrigated vegetable production system receiving annual additions of fresh and composted paper mill residuals (PMR). Foliar diseases caused by Pseudomonas syringae pv. syringae on snap bean (bacterial brown spot) and P. s. pv. lachrymans on cucumber (angular leaf spot) are the focus of this report. The experiment consisted of a 3-year crop rotation of potato (1998 and 2001), snap bean (1999 and 2002), and cucumber (2000). Treatments included a non-amended fertilizer control and two rates of fresh PMR, PMR composted alone (PMRC), and PMR composted with bark (PMRB). Soil measures included total soil carbon (TC) and nitrogen (TN), particulate organic matter carbon (POMC) and nitrogen (POMN), volumetric soil moisture (VM) and in situ NO₃-N. Multiple regression (MR) and principal component analyses (PCA) were conducted to identify key soil properties that influenced the amount of disease. On average, the amount of TC in plots amended with PMR composts increased 77-178% from 1999 to 2002 compared to the non-amended soils. In 1999, a year in which compost additions reduced the amount of bacterial brown spot of bean, TC explained 42% of the total variation in disease severity in the best MR model. Midseason TN alone was inversely related to angular leaf spot incidence in 2000, while POMN explained 51% of the variation in the best MR model for that year. In 2002, a year in which PMRC-amended soils exacerbated brown spot symptoms, midseason quantities of TN explained 80% of the variation in disease severity. Unique to 2002, NO₃-N alone positively correlated with disease severity. Overall, the influence of soil carbon on disease severity was displaced by the increasing importance of TN and NO₃-N, indicating a transition from a C-dependent to an N-dependent system.  相似文献   

A small animal clinical and epidemiological relational database     

D. J. W. Stone  M. V. Thrusfield   《Preventive veterinary medicine》1989,7(4):289-302

A mainframe relational database management system (RDBMS), ORACLE, has been applied to small animal clinical records to facilitate storage and querying of case data for clinical and epidemiological use. Coded records are entered into the computer via a “user-friendly” interface which validates the input. Clinicians' queries similarly utilise an interface that generates query commands from four simple queries. Epidemiologists' queries, in contrast, require considerable flexibility and so use the main RDBMS language, SQL*Plus. A data administrator manages the security and integrity of the RDBMS.  相似文献   

Evaluation of the efficacy of an oil-emulsion bacterin for protecting chickens against Salmonella enteritidis.     

R K Gast  H D Stone  P S Holt  C W Beard 《Avian diseases》1992,36(4):992-999

To assess the potential protective efficacy of a Salmonella enteritidis bacterin, an acetone-killed oil-emulsion vaccine was prepared from a phage type 13a S. enteritidis strain and administered subcutaneously to hens in two experiments. Hens were housed individually, and every other hen was vaccinated (at 23 weeks of age in one experiment and at 45 weeks in the other). A second (booster) bacterin injection was administered 6 weeks later in both experiments. Three weeks after the second vaccination, all hens were challenged with an oral dose of approximately 10(9) cells of a heterologous (phage type 14b) S. enteritidis strain. In both trials, S. enteritidis was isolated from fewer internal organs (spleens, ovaries, and oviducts) and pools of egg contents from vaccinated hens than from unvaccinated control hens. Vaccination did not, however, affect the percentage of hens that shed S. enteritidis in feces in either experiment.  相似文献