ABSTRACT
In August 2009 the Sun illuminated Saturn's rings from almost exactly edge-on, revealing a subtle corrugation that extends across the entire C ring. This corrugation's amplitude is 2 to 20 meters and its wavelength is 30 to 80 kilometers. Radial trends in the corrugation's wavelength indicate that this structure--like a similar corrugation previously identified in the D ring--results from differential nodal regression within a ring that became tilted relative to Saturn's equator plane in 1983. We suggest that this initial tilt arose because interplanetary debris struck the rings. The corrugation's radial extent implies that the impacting material was a dispersed cloud of debris instead of a single object, and the corrugation's amplitude indicates that the debris' total mass was ~10(11) to 10(13) kilograms.
ABSTRACT
Images acquired of Saturn's rings and small moons by the Cassini Imaging Science Subsystem (ISS) during the first 9 months of Cassini operations at Saturn have produced many new findings. These include new saturnian moons; refined orbits of new and previously known moons; narrow diffuse rings in the F-ring region and embedded in gaps within the main rings; exceptionally fine-scale ring structure in moderate- to high-optical depth regions; new estimates for the masses of ring-region moons, as well as ring particle properties in the Cassini division, derived from the analysis of linear density waves; ring particle albedos in select ring regions; and never-before-seen phenomena within the rings.
ABSTRACT
The Cassini Imaging Science Subsystem acquired high-resolution imaging data on the outer Saturnian moon, Phoebe, during Cassini's close flyby on 11 June 2004 and on Iapetus during a flyby on 31 December 2004. Phoebe has a heavily cratered and ancient surface, shows evidence of ice near the surface, has distinct layering of different materials, and has a mean density that is indicative of an ice-rock mixture. Iapetus's dark leading side (Cassini Regio) is ancient, heavily cratered terrain bisected by an equatorial ridge system that reaches 20 kilometers relief. Local albedo variations within and bordering Cassini Regio suggest mass wasting of ballistically deposited material, the origin of which remains unknown.
Subject(s)
Saturn , Extraterrestrial Environment , Geologic Sediments , Ice , Spacecraft , WaterABSTRACT
The Cassini Imaging Science Subsystem (ISS) began observing Saturn in early February 2004. From analysis of cloud motions through early October 2004, we report vertical wind shear in Saturn's equatorial jet and a maximum wind speed of approximately 375 meters per second, a value that differs from both Hubble Space Telescope and Voyager values. We also report a particularly active narrow southern mid-latitude region in which dark ovals are observed both to merge with each other and to arise from the eruptions of large, bright storms. Bright storm eruptions are correlated with Saturn's electrostatic discharges, which are thought to originate from lightning.
Subject(s)
Saturn , Atmosphere , Extraterrestrial Environment , Spacecraft , WindABSTRACT
This study compared the functioning of 20 rural cancer survivors, aged 6 to 16 years, with that of 40 age- and gender-matched school peers. Social competence and emotional health were evaluated, along with academic performance and physical limitations. Eight measures were used: the teacher and parent Child Behavior Check Lists, the Health Resources Inventory, the Vineland Revised Scale of Social Maturity, the Piers-Harris Child's Self-Concept Scale, the Parcel and Meyers' Health Locus of Control, the Moos' Family Environment Scale, and the Functional Status II(r). Cancer survivors and controls had similar attitudes about self-esteem, family conflicts, physical functioning, social skills, independence, and sense of control over health. Both parents and teachers noted poorer social competence among the cancer survivors than among controls, but parents of survivors reported more behavior problems, whereas teachers stressed poorer school performance. Routine screening for emotional health, social competence, and academic performance should be part of the follow-up care of pediatric cancer survivors.
Subject(s)
Child Behavior Disorders/epidemiology , Mental Health , Neoplasms/psychology , Rural Health , Social Adjustment , Activities of Daily Living , Adaptation, Psychological , Adolescent , Attitude to Health , Case-Control Studies , Child , Child Behavior Disorders/prevention & control , Child Behavior Disorders/psychology , Educational Status , Family/psychology , Female , Humans , Internal-External Control , Male , Mass Screening , Neoplasms/mortality , Surveys and Questionnaires , Survival RateABSTRACT
The Maxwell equation is solved for axial birefringence due to electric and magnetic rectification measured with a collinear unpolarized probe laser by switching an intense circularly polarized pump laser from right to left. Axial birefringence is caused by vector products of electric and magnetic conjugate components of the intense electromagnetic field. Axial birefringence can be measured with a modified Rayleigh refractometer and depends on new three-and four-rank molecular property tensors.
ABSTRACT
A study was designed to investigate the genetic origin of hydatidiform moles. Fifty-nine specimens were obtained and, on a histological basis, separated into two entities: complete and partial. The study of the genetic origin of the 15 partial moles, using cytogenetic and biochemical markers, is described. All the partial moles examined cytogenetically were triploid. One had 71 chromosomes. The sex chromosome complements of seven cases were six XXY and one XXX. Origin by dispermy was possible in seven cases and was proven in four. With the use of biochemical markers a maternal contribution was identified in three cases, and the isoenzyme pattern suggested a trisomic state for at least one locus in four cases. The mechanism of origin of partial moles was compared with spontaneously aborted and liveborn triploids. All the patients were followed up for at least 9 months, and none required treatment for persistent trophoblastic activity.
Subject(s)
Chromosome Aberrations , Hydatidiform Mole/genetics , Abortion, Spontaneous/genetics , Adult , Chromosome Banding , Female , Humans , Hydatidiform Mole/pathology , Karyotyping , Male , Polyploidy , Pregnancy , Sex Chromosomes , Trophoblastic Neoplasms/complications , Uterine Neoplasms/complicationsABSTRACT
A high-frequency radar remote-sensing system for measuring and mapping near-surface ocean currents in coastal waters has been analyzed and described. A transportable prototype version of the system was designed, constructed, and tested. With two units operating tens of kilometers apart, the currents were mapped in near real time at a grid of points 3 by 3 km covering areas exceeding 2000 kM(2), out to a distance of about 70 km from the shore. Preliminary estimates of the precision of current velocity measurements show it to be better than 30 cm/sec.