Hydrated silicate minerals on Mars observed by the Mars Reconnaissance Orbiter CRISM instrument.

Phyllosilicates, a class of hydrous mineral first definitively identified on Mars by the OMEGA (Observatoire pour la Mineralogie, L'Eau, les Glaces et l'Activitié) instrument, preserve a record of the interaction of water with rocks on Mars. Global mapping showed that phyllosilicates are widespread but are apparently restricted to ancient terrains and a relatively narrow range of mineralogy (Fe/Mg and Al smectite clays). This was interpreted to indicate that phyllosilicate formation occurred during the Noachian (the earliest geological era of Mars), and that the conditions necessary for phyllosilicate formation (moderate to high pH and high water activity) were specific to surface environments during the earliest era of Mars's history. Here we report results from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) of phyllosilicate-rich regions. We expand the diversity of phyllosilicate mineralogy with the identification of kaolinite, chlorite and illite or muscovite, and a new class of hydrated silicate (hydrated silica). We observe diverse Fe/Mg-OH phyllosilicates and find that smectites such as nontronite and saponite are the most common, but chlorites are also present in some locations. Stratigraphic relationships in the Nili Fossae region show olivine-rich materials overlying phyllosilicate-bearing units, indicating the cessation of aqueous alteration before emplacement of the olivine-bearing unit. Hundreds of detections of Fe/Mg phyllosilicate in rims, ejecta and central peaks of craters in the southern highland Noachian cratered terrain indicate excavation of altered crust from depth. We also find phyllosilicate in sedimentary deposits clearly laid by water. These results point to a rich diversity of Noachian environments conducive to habitability.

The landing of the NEAR-Shoemaker spacecraft on asteroid 433 Eros.

The NEAR-Shoemaker spacecraft was designed to provide a comprehensive characterization of the S-type asteroid 433 Eros (refs 1,2,3), an irregularly shaped body with approximate dimensions of 34 x 13 x 13 km. Following the completion of its year-long investigation, the mission was terminated with a controlled descent to its surface, in order to provide extremely high resolution images. Here we report the results of the descent on 12 February 2001, during which 70 images were obtained. The landing area is marked by a paucity of small craters and an abundance of 'ejecta blocks'. The properties and distribution of ejecta blocks are discussed in a companion paper. The last sequence of images reveals a transition from the blocky surface to a smooth area, which we interpret as a 'pond'. Properties of the 'ponds' are discussed in a second companion paper. The closest image, from an altitude of 129 m, shows the interior of a 100-m-diameter crater at 1-cm resolution.

Imaging of small-scale features on 433 Eros from NEAR: evidence for a complex regolith.

On 25 October 2000, the Near Earth Asteroid Rendevous (NEAR)-Shoemaker spacecraft executed a low-altitude flyover of asteroid 433 Eros, making it possible to image the surface at a resolution of about 1 meter per pixel. The images reveal an evolved surface distinguished by an abundance of ejecta blocks, a dearth of small craters, and smooth material infilling some topographic lows. The subdued appearance of craters of different diameters and the variety of blocks and different degrees of their burial suggest that ejecta from several impact events blanketed the region imaged at closest approach and led to the building up of a substantial and complex regolith consisting of fine materials and abundant meter-sized blocks.

NEAR at eros: imaging and spectral results

Eros is a very elongated (34 kilometers by 11 kilometers by 11 kilometers) asteroid, most of the surface of which is saturated with craters smaller than 1 kilometer in diameter. The largest crater is 5.5 kilometers across, but there is a 10-kilometer saddle-like depression with attributes of a large degraded crater. Surface lineations, both grooves and ridges, are prominent on Eros; some probably exploit planes of weakness produced by collisions on Eros and/or its parent body. Ejecta blocks (30 to 100 meters across) are abundant but not uniformly distributed over the surface. Albedo variations are restricted to the inner walls of certain craters and may be related to downslope movement of regolith. On scales of 200 meters to 1 kilometer, Eros is more bland in terms of color variations than Gaspra or Ida. Spectra (800 to 2500 nanometers) are consistent with an ordinary chondrite composition for which the measured mean density of 2.67 +/- 0.1 grams per cubic centimeter implies internal porosities ranging from about 10 to 30 percent.

Imaging of asteroid 433 eros during NEAR's flyby reconnaissance

During the 23 December 1998 flyby of asteroid 433 Eros, the Near-Earth Asteroid Rendezvous (NEAR) spacecraft obtained 222 images of Eros, as well as supporting spectral observations. The images cover slightly more than two-thirds of Eros (best resolution is approximately 400 meters per pixel) and reveal an elongated, cratered body with a linear feature extending for at least 20 kilometers. Our observations show that Eros has dimensions of 33 x 13 x 13 kilometers. The volume, combined with the mass determined by the NEAR radio science experiment, leads to a density of 2.5 +/- 0.8 grams per cubic centimeter. This relatively high density, and the presence of an extensive linear feature, suggest that Eros may be a structurally coherent body.

Use of a preanesthetic video for facilitation of parental education and anxiolysis before pediatric ambulatory surgery.

UNLABELLED: In this study, we evaluated the effects of viewing an educational videotape about pediatric anesthesia on measures of parental knowledge of anesthesia and preoperative anxiety using a randomized, controlled design. During their routine preoperative visit, 85 parents of children scheduled to undergo ambulatory surgical procedures under general anesthesia were randomized to view either the experimental videotape about pediatric anesthesia or a control videotape with no medical content. Before and immediately after viewing the assigned videotape, parents completed measures of situational anxiety (State-Trait Anxiety Inventory-State), preoperative anxiety and need for information (Amsterdam Preoperative Anxiety and Information Scale), and anesthesia knowledge (Standard Anesthesia Learning Test). Repeated-measures analyses of variance showed that parents who viewed the experimental videotape showed a significant increase in anesthesia knowledge (P < 0.022) and a significant reduction in their state of anxiety (P < 0.031), anesthesia-specific anxiety, and need for information (P < 0.0001) compared with the control group. These results demonstrated that viewing a preoperative educational videotape about pediatric anesthesia can provide immediate educational and anxiolytic benefits for parents of children undergoing ambulatory surgery. The duration of these benefits remains to be determined. IMPLICATIONS: In this study, we demonstrated the benefits of viewing an educational videotape about pediatric anesthesia on measures of parental knowledge of anesthesia and preoperative anxiety using a randomized, controlled design. We found that videotape viewing facilitated preoperative preparation and lessened preoperative anxiety.

Validation of measures of parents' preoperative anxiety and anesthesia knowledge.

UNLABELLED: Parents' anxiety about their children's anesthesia may adversely affect the children's outcomes and compromise the quality of informed consent. Studies of these issues have been limited by the lack of validated measures of parental anxiety and knowledge surrounding anesthesia. In the present study, we evaluated psychometric properties of the Amsterdam Preoperative Anxiety and Information Scale (APAIS) and the Standard Anesthesia Learning Test (SALT) among 85 parents who participated in an evaluation of the effects of a videotape about pediatric anesthesia. The results supported the internal consistency, test-retest reliability, and concurrent validity of both instruments and documented the equivalence of two forms of the SALT. Factor analysis supported the previously demonstrated factor structure of the APAIS, further confirming its construct validity. We conclude that the APAIS and SALT are reliable and valid measures of parental anxiety and knowledge of pediatric anesthesia that can be used for clinical and research purposes. IMPLICATIONS: This study verified the reliability and validity of two questionnaires for measuring parents' knowledge and anxiety about pediatric anesthesia. These questionnaires can be used in further research on factors affecting parental anxiety and knowledge before their children's surgery.

The Web, Communication Trends, and Children's Health. Part 5: Encouraging positive and safe Internet use.

The previous four articles in this series on the Web, Communication Trends, and Children's Health (Clinical Pediatrics, March-June, 1998) have shown that the Internet is a rich interactive window on the world, with health-related resources not readily available elsewhere. While the Internet brings great benefits, there are also some significant potential drawbacks. In this final article of the series, we focus on the precautions parents, teachers, and caregivers can take to help children and their families use the Internet wisely and safely.

The Web, Communication Trends, and Children's Health. Part 2: The Web and the practice of pediatrics.

This article, Part 2 of a five-part series on The Web, Communications Trends, and Children's Health, describes how the Web's "virtual library" lets pediatricians tap into an evergrowing body of resources, including the latest medical information and online Continuing Medical Education. In addition, the Web creates new ways to practice pediatrics and share patient information.

The Web, communication trends, and children's health. Part 4: How children use the Web.

Children are embracing the Internet and the World Wide Web. How are they using it and what do they find? This article, the fourth in a five-part series, explores the "whys" and the "wherefores" of children's Web use. Included are online recourses geared specifically for children, including health, educational, and entertainment sites.

The Web, communication trends, and children's health. Part 3: The Web and health consumers.

The World Wide Web has the potential to change significantly how medical care is both delivered and consumed. This, the third of a five-part series on The Web, Communication Trends, and Children's Health, considers how families can use the Internet to find consumer health information and to access care. This article also discusses some of the potential and limitations of Web-based health resources. Part 1 of this series described the development and technology of the Internet and the Web. Part 2 suggested how pediatricians can use the Web to gather medical information and how the increasing capabilities of the Web may affect clinical practice.

The Web, communication trends, and children's health. Part 1: Development and technology of the Internet and Web.

The Internet and The World Wide Web are changing the way pediatricians find medical information and provide care. This article, the first in a four-part series on The Web, Communication Trends, and Children's Health, published in consecutive issues of this journal, describes how the Web was created and how its multimedia capabilities are affecting information exchange.

NEAR's flyby of 253 mathilde: images of a C asteroid

On 27 June 1997, the Near Earth Asteroid Rendezvous (NEAR) spacecraft flew within 1212 kilometers of asteroid 253 Mathilde. Mathilde is an irregular, heavily cratered body measuring 66 kilometers by 48 kilometers by 46 kilometers. The asteroid's surface is dark (estimated albedo between 0.035 and 0.050) and similar in color to some CM carbonaceous chondrites. No albedo or color variations were detected. The volume derived from the images and the mass from Doppler tracking of the spacecraft yield a mean density of 1.3 +/- 0.2 grams per cubic centimeter, about half that of CM chondrites, indicating a porous interior structure.

The endocrine spectrum of septo-optic dysplasia.

Six children with septo-optic dysplasia were evaluated at the Children's Hospital of Philadelphia. There was a common history of young, nulliparous mothers. The clinical presentation of these children differed according to age of presentation and was a function of the degree and type of hypothalamic-pituitary and ophthalmologic impairment. Endocrine evaluation revealed four of six children to be growth hormone deficient, four of six to have hypothalamic hypothyroidism, and two of four to have elevated prolactin levels. One of the patients demonstrated adrenocorticotropic hormone deficiency, and one had diabetes insipidus. Neuroanatomic findings in the children were variable, but, in general, the rare syndrome did not carry as grave a morbidity as had been reported previously. Our data support a high degree of hypothalamic impairment in septo-optic dysplasia.