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PubMed1996

The Morphogenesis of Bands and Zonal Winds in the Atmospheres on the Giant Outer Planets

The atmospheres of Jupiter, Saturn, Uranus, and Neptune were modeled as shallow layers of turbulent fluid overlying a smooth, spherical interior. With only the observed values of radius, rotation rate, average wind velocity, and mean layer thickness as model parameters, bands and jets spontaneously emerged from random initial conditions. The number, width, and amplitude of the jets, as well as the dominance of anticyclonic vortices, are in good agreement with observations for all four planets.

Journal Article↗
PubMed1997

Depletion of the Outer Asteroid Belt

During the early history of the solar system, it is likely that the outer planets changed their distance from the sun, and hence, their influence on the asteroid belt evolved with time. The gravitational influence of Jupiter and Saturn on the orbital evolution of asteroids in the outer asteroid belt was calculated. The results show that the sweeping of mean motion resonances associated with planetary migration efficiently destabilizes orbits in the outer asteroid belt on a time scale of 10 million years. This mechanism provides an explanation for the observed depletion of asteroids in that region.

Journal Article↗
PubMed1998

The origin of chondrules at jovian resonances

Isotopic dating indicates that chondrules were produced a few million years after the solar nebula formed. This timing is incompatible with dynamical lifetimes of small particles in the nebula and short time scales for the formation of planetesimals. Temporal and dynamical constraints can be reconciled if chondrules were produced by heating of debris from disrupted first-generation planetesimals. Jovian resonances can excite planetesimal eccentricities enough to cause collisional disruption and melting of dust by bow shocks in the nebular gas. The ages of chondrules may indicate the times of Jupiter's formation and dissipation of gas from the asteroidal region.

Journal Article↗
PubMed1998

Discovery of a low-mass brown dwarf companion of the young nearby star G 196-3

A substellar-mass object in orbit at about 300 astronomical units from the young low-mass star G 196-3 was detected by direct imaging. Optical and infrared photometry and low- and intermediate-resolution spectroscopy of the faint companion, hereafter referred to as G 196-3B, confirm its cool atmosphere and allow its mass to be estimated at 25-10+15 Jupiter masses. The separation between the objects and their mass ratio suggest the fragmentation of a collapsing cloud as the most likely origin for G 196-3B, but alternatively it could have originated from a protoplanetary disc that has been dissipated. Whatever the formation process was, the young age of the primary star (about 100 million years) demonstrates that substellar companions can form on short time scales.

Journal Article↗
PubMed1998

The dusty atmosphere of the brown dwarf Gliese 229B.

The brown dwarf Gliese 229B has an observable atmosphere too warm to contain ice clouds like those on Jupiter and too cool to contain silicate clouds like those on low-mass stars. These unique conditions permit visibility to higher pressures than possible in cool stars or planets. Gliese 229B's 0.85- to 1.0-micrometer spectrum indicates particulates deep in the atmosphere (10 to 50 bars) having optical properties of neither ice nor silicates. Their reddish color suggests an organic composition characteristic of aerosols in planetary stratospheres. The particles' mass fraction (10(-7)) agrees with a photochemical origin caused by incident radiation from the primary star and suggests the occurrence of processes native to planetary stratospheres.

Astronomical Phenomena↗
PubMed1999

The origin of chaos in the outer solar system

Classical analytic theories of the solar system indicate that it is stable, but numerical integrations suggest that it is chaotic. This disagreement is resolved by a new analytic theory. The theory shows that the chaos among the jovian planets results from the overlap of the components of a mean motion resonance among Jupiter, Saturn, and Uranus, and provides rough estimates of the Lyapunov time (10(7) years) and the dynamical lifetime of Uranus (10(18) years). The jovian planets must have entered the resonance after all the gas and most of the planetesimals in the protoplanetary disk were removed.

Journal Article↗
PubMed2000

Teleconvection: remotely driven thermal convection in rotating stratified spherical layers.

We report the discovery of a convective phenomenon found to occur in a rotating spherical system in which an inner convectively unstable fluid layer is bounded by a corotating outer convectively stable fluid layer. Although convection is thermally driven in the unstable interior, the resulting convective motions concentrate primarily in the stable outer region. This phenomenon, which we term teleconvection, suggests that fluid motions observed at the "surface" of a planet (such as Jupiter's alternating zonal winds) may be driven by an energy source located deep inside the planet.

Journal Article↗
PubMed1995

Metal ions in the atmosphere of Neptune.

Microwave propagation experiments performed with Voyager 2 at Neptune revealed sharp layers of electrons in Neptune's lower ionosphere with densities of approximately 10(4) per cubic centimeter. These layers are reminiscent of the sporadic-E layers in the Earth's ionosphere, and when taken together with data from the other giant planets, these data confirm the importance of the magnetic field in layer formation. A photochemical model that incorporates species produced by meteoroid ablation predicts that singly ionized magnesium is the most likely metal to be found in the layers, although laboratory data on the kinetics of metallic atoms and ions in a reducing environment are lacking. The metal chemistry discussed here is directly relevant to the abundant metals observed at the impact site of the G fragment of comet Shoemaker Levy 9 on Jupiter.

Atmosphere↗
PubMed1995

A survey of DNA polymorphism within the genus Capsicum and the fingerprinting of pepper cultivars.

Interspecific genetic variation was examined in the genus Capsicum based on shared restriction fragments in Southern analyses. Four distinct clusters were delineated among 21 accessions of cultivated and wild pepper (C. annuum, C. baccatum, C. chacoense, C. chinense, and C. frutescens). Three tight clusters comprised of accessions belonging to C. annuum, C. frutescens, and C. baccatum, respectively, were formed, along with a fourth cluster comprised of one accession each of C. chinense and C. chacoense. All accessions were differentiated by this technique, and the clusters corresponded closely to previous morphology-based classification. Sufficient DNA polymorphism exists among these accessions that segregating populations useful for restriction fragment length polymorphism (RFLP) mapping could be constructed using any two pepper accessions as parents. Regression analysis indicates that genetic distance is a good predictor (R2 = 0.872) of the level of mappable DNA polymorphism in Capsicum. Intraspecific variability was examined among four C. annuum cultivars (NuMex R Naky, Jupiter, Perennial, and Criollo de Morelos 334) using both RFLPs and randomly amplified polymorphic DNA (RAPDs), allowing a comparative evaluation of the two techniques. Seventeen percent of the clones used singly in RFLP analyses were sufficient for the differentiation of these varieties, as were 12.5% of the RAPD PCR amplifications. Dendrograms constructed from RFLP and RAPD analyses of the intraspecific data are similar but not identical. Southern analysis and RAPD PCR should be useful for DNA fingerprinting and the discrimination of closely related C. annuum genotypes.

Agriculture↗
PubMed2000

Interobserver and intraobserver variation in classification systems for fractures of the distal humerus.

We assessed the inter- and intraobserver variation in classification systems for fractures of the distal humerus. Three orthopaedic trauma consultants, three trauma registrars and three consultant musculoskeletal radiologists independently classified 33 sets of radiographs of such fractures on two occasions, each using three separate systems. For interobserver variation, the Riseborough and Radin system produced 'moderate' agreement (kappa = 0.513), but half of the fractures were not classifiable by this system. For the complete AO system, agreement was 'fair' (kappa = 0.343), but if only AO type and group or AO type alone was used, agreement improved to 'moderate' and 'substantial', respectively (kappa = 0.52 and 0.66). Agreement for the system of Jupiter and Mehne was 'fair' (kappa = 0.295). Similar levels of intraobserver variation were found. Systems of classification are useful in decision-making and evaluation of outcome only if there is agreement and consistency among observers. Our study casts doubt on these aspects of the systems currently available for fractures of the distal humerus.

Classification↗
PubMed2006

Effect of wavefront error on 10(-7) contrast measurements.

Received October 11, 2005; accepted November 10, 2005; posted December 2, 2005 (Doc. ID 65234) We have measured a contrast of 6.5 x 10(-8) from 10 to 25 lambda/D in visible light on the Extreme Adaptive Optics testbed, using a shaped pupil for diffraction suppression. The testbed was designed with a minimal number of high-quality optics to ensure low wavefront error and uses a phase-shifting diffraction interferometer for metrology. This level of contrast is within the regime needed for imaging young Jupiter-like planets, a primary application of high-contrast imaging. We have concluded that wavefront error, not pupil quality, is the limiting error source for improved contrast in our system.

Journal Article↗
PubMed2005

Relating statin therapy to C-reactive protein levels.

Inflammation is pivotal in atherosclerosis, and C-reactive protein (CRP) is an inflammatory marker that predicts cardiovascular events. The Reversal of Atherosclerosis with Aggressive Lipid Lowering (REVERSAL) trial compared the standard lowering of low-density lipoprotein (LDL)-cholesterol with pravastatin 40 mg/day, with the intense lowering of LDL-cholesterol with atorvastatin 80 mg/day on atheroma volume in patients with coronary artery disease, and showed that the atheroma progressed by 2.7% in the pravastatin group, and remained unchanged in the atorvastatin group. At 18 months follow-up, the CRP levels were reduced from a baseline level of 2.8 mg/l to 1.8 mg/l by atorvastatin, whereas pravastatin had little effect, and there was a good correlation between both the ultrasonographic progression of disease and the reduction in CRP levels. The Pravastatin or Atorvastatin Evaluation and Infection Therapy--Thrombolysis in Myocardial Infarction 22 (PROVE IT-TIMI 22) trial compared the long-term effects of the standard lowering of LDL-cholesterol with pravastatin, with the intense lowering of LDL-cholesterol with atorvastatin in patients with an acute coronary syndrome. The primary end point was the first of death, myocardial infarction, unstable angina requiring hospitalisation, revascularisation or stroke, and, at the end of 2 years, was greater in the pravastatin than the atorvastatin group (26.3 versus 22.4%, respectively). Patients with CRP levels of 2 mg/l had lower rates of recurrent myocardial infarction or death from coronary causes than patients with higher levels. Further analysis should be undertaken to assess cardiovascular risk at different levels of CRP, including assessing cardiovascular risk at different levels in men and women. Definitive results about the importance of lowering CRP levels are not likely to be obtained until the results of the Justification for Use of Statins in Primary Prevention, an Intervention Trial in Evaluating Rosuvastatin (JUPITER) study are published.

Journal Article↗
PubMed1999

Intra-articular fractures of the distal aspect of the radius: arthroscopically assisted reduction compared with open reduction and internal fixation.

BACKGROUND: There is no consensus that an arthroscopically guided operation can improve the anatomical and functional results of treatment of intra-articular fractures of the distal aspect of the radius. The purpose of the present prospective study was to determine the usefulness of arthroscopically assisted reduction of displaced intra-articular fractures of the distal aspect of the radius by comparing the results of that procedure with those of conventional open reduction and internal fixation. METHODS: Thirty-four fractures were treated with arthroscopically guided reduction with use of one volar and two dorsal arthroscopic portals. The fractures were pinned, and external fixation was used with or without autogenous bone graft. Intraoperative fluoroscopy was not used. Forty-eight fractures were treated with conventional open reduction and internal fixation with a plate and screws or with pinning, with or without external fixation. The average duration of follow-up for all fractures was thirty-one months. RESULTS: The scores for overall outcome, assessed with use of the system of Gartland and Werley and that of Green and O'Brien as modified by Cooney et al., demonstrated that the group that had had an arthroscopically assisted procedure had better outcomes than the group that had had conventional open reduction and internal fixation. The group that had had an arthroscopically assisted procedure also had significantly better ranges of flexion-extension and radial-ulnar deviation of the wrist and grip strength (p<0.05). We detected an association between the maximum step and gap displacement and evidence of osteoarthritis of the radiocarpal joint (p<0.001), but we did not find a significant association, with the numbers available, between the scores for osteoarthritis, graded according to the scale of Knirk and Jupiter, and the scores for overall outcome, assessed with the scale of Gartland and Werley and the modified system of Green and O'Brien, in either group (p = 0.376). The radiographic results showed that the patients who had had an arthroscopically assisted procedure had better reduction of volar tilt, ulnar variance, and articular (gap) displacement than did those who had been managed with conventional open reduction and internal fixation (p<0.05 for each comparison). CONCLUSIONS: An arthroscopically guided operation achieved an accurate reduction of intra-articular fractures of the distal aspect of the radius. Minimum capsular and adjacent soft-tissue scarring reduced postoperative contracture, which improved the overall functional results. We recommend arthroscopically guided reduction and internal fixation not only for young adults but for all patients who are less than seventy years old and have an intra-articular fracture of the distal part of the radius with more than one millimeter of displacement on plain radiographs.

Adolescent↗
PubMed2000

[Thermophiles and life science in space].

Thermophiles are microorganisms that can grow at temperatures higher than 50 or 60 degrees C. There are thermophilic eubacteria and thermophilic archaebacteria. Thermophilic microorganisms can be found geothermally and hydrothermally active area. The water penetrates into deep subsurface around thermal area and reacts with hot basalt. Some of the compounds in the water are reduced by the reaction. The water returned to the surface and reacts with seawater or air, depending on the location of the thermal area. Many types of autotrophes and heterotrophes were found near thermally active area. The microorganisms form the ecosystem based on the redox chemical reactions. All of the structural elements in thermophilic microorganisms are thermophilic or thermostable. Proteins found in microorganisms are thermostable. Though several common characteristics can be found in thermostable proteins, it is not easy to attribute the stability to specific amino acid residues. DNA in thermophiles is stabilized by increasing the G+C content or by histone-like DNA binding proteins. There are several molecular biological and geological evidences to support the relation between ancient life forms and thermal activity on the Earth. Thermophiles of different life forms may be found in thermally active area, in such as those that may be present in satellites of Jupiter.

Archaea↗
PubMed1994

University biology and music majors' emotional ratings of musical stimuli and their physiological correlates of heart, rate, finger temperature, and blood pressure.

Physiological responses associated with the ratings of musical stimuli were investigated. For 101 university music and biology students in the experimental group, heart rate, blood pressure, and finger temperature were measured before and after listening to about 10 min. of music (Venus and Jupiter from Holst's The Planets) in an anechoic chamber. They also served as their own controls by sitting in silence for about 10 min. No significant differences were found on the three measures for the two musical stimuli between the musical or control conditions or between the two majors.

Adult↗
PubMed2002

PTSD symptoms of mothers following occurrence of a disaster affecting their children.

This study investigated the PTSD symptoms of 37 mothers whose adolescent children had been directly involved in a disaster, the Jupiter sinking in 1988. This group included mothers whose children were (a) not diagnosed with Posttraumatic Stress Disorder and (b) were diagnosed with Posttraumatic Stress Disorder. The measure used was the Posttraumatic Stress Disorder Symptom Scale. Women whose children were involved in the disaster presented PTSD symptoms. 35% (n = 13) were diagnosed with PTSD 3 mo. after the disaster, and 89% (n = 3) of them were diagnosed with PTSD 6 yr. afterward. This effect was greater in the subgroup whose children had developed traumatic stress disorder following the disaster.

Child↗
PubMed2002

Use of injectable calcium phosphate in the treatment of intra-articular distal radius fractures.

This study reviewed 19 patients with intra-articular fractures of the distal end ofthe radius treated with augmented external fixation and injectable calcium phosphate (Norian SRS; Norian Corp, Cupertino, Calif) between November 1997 and July 2000. Average patient age was 52 years, and average follow-up was 16.3 months. Patients were evaluated clinically and radiographically using the modified Mayo Wrist Score and Knirk and Jupiter's criteria, respectively. Overall results are comparable to those from other studies of intra-articular distal radius fractures in which other grafts have been used.

Adult↗
PubMed2000

The long-term psychological effects of a disaster experienced in adolescence: II: General psychopathology.

Children and adolescents exposed to trauma can suffer major adverse psychological effects including not only post-traumatic stress but also other psychological disorders. This study investigates the long-term course of general psychopathology following trauma in adolescence using a standardised diagnostic interview and comparisons with a matched control group. Young people (N= 216) who as teenagers had survived a shipping disaster-the sinking of the "Jupiter" in Greek waters-between 5 and 8 years previously and 87 young people as matched controls were interviewed. The survivors showed raised rates of diagnosis in a range of anxiety and affective disorders during the follow-up period. The highest rates were among the survivors who had developed Post-Traumatic Stress Disorder (PTSD), and those survivors who had not were generally similar to the controls. Onset of anxiety and affective disorders varied between being indefinitely close to the disaster to years later. Differences in rates of disorder between the survivor and control groups had lessened by the time of follow-up but were still apparent, due to continuing distress among the survivors still suffering from PTSD, and to a lesser extent among those who had recovered from PTSD. Generalisability of the findings are discussed.

Adolescent↗