Ammoniated phyllosilicates with a likely outer Solar System origin on (1) Ceres.

Studies of the dwarf planet (1) Ceres using ground-based and orbiting telescopes have concluded that its closest meteoritic analogues are the volatile-rich CI and CM carbonaceous chondrites. Water in clay minerals, ammoniated phyllosilicates, or a mixture of Mg(OH)2 (brucite), Mg2CO3 and iron-rich serpentine have all been proposed to exist on the surface. In particular, brucite has been suggested from analysis of the mid-infrared spectrum of Ceres. But the lack of spectral data across telluric absorption bands in the wavelength region 2.5 to 2.9 micrometres--where the OH stretching vibration and the H2O bending overtone are found--has precluded definitive identifications. In addition, water vapour around Ceres has recently been reported, possibly originating from localized sources. Here we report spectra of Ceres from 0.4 to 5 micrometres acquired at distances from ~82,000 to 4,300 kilometres from the surface. Our measurements indicate widespread ammoniated phyllosilicates across the surface, but no detectable water ice. Ammonia, accreted either as organic matter or as ice, may have reacted with phyllosilicates on Ceres during differentiation. This suggests that material from the outer Solar System was incorporated into Ceres, either during its formation at great heliocentric distance or by incorporation of material transported into the main asteroid belt.

Global elemental maps of the moon: the Lunar Prospector gamma-Ray spectrometer.

Lunar Prospector gamma-ray spectrometer spectra along with counting rate maps of thorium, potassium, and iron delineate large compositional variations over the lunar surface. Thorium and potassium are highly concentrated in and around the nearside western maria and less so in the South Pole-Aitken basin. Counting rate maps of iron gamma-rays show a surface iron distribution that is in general agreement with other measurements from Clementine and the Lunar Prospector neutron detectors.

Fluxes of fast and epithermal neutrons from Lunar Prospector: evidence for water ice at the lunar poles.

Maps of epithermal- and fast-neutron fluxes measured by Lunar Prospector were used to search for deposits enriched in hydrogen at both lunar poles. Depressions in epithermal fluxes were observed close to permanently shaded areas at both poles. The peak depression at the North Pole is 4.6 percent below the average epithermal flux intensity at lower latitudes, and that at the South Pole is 3.0 percent below the low-latitude average. No measurable depression in fast neutrons is seen at either pole. These data are consistent with deposits of hydrogen in the form of water ice that are covered by as much as 40 centimeters of desiccated regolith within permanently shaded craters near both poles.

Ulysses solar wind plasma observations at high southerly latitudes.

Solar wind plasma observations made by the Ulysses spacecraft through -80.2 degrees solar latitude and continuing equatorward to -40.1 degrees are summarized. Recurrent high-speed streams and corotating interaction regions dominated at middle latitudes. The speed of the solar wind was typically 700 to 800 kilometers per second poleward of -35 degrees . Corotating reverse shocks persisted farther south than did forward shocks because of the tilt of the heliomagnetic streamer belt. Sporadic coronal mass ejections were seen as far south as -60.5 degrees . Proton temperature was higher and the electron strahl was broader at higher latitudes. The high-latitude wind contained compressional, pressure-balanced, and Alfvénic structures.

Jupiter's Magnetosphere: Plasma Description from the Ulysses Flyby.

Plasma observations at Jupiter show that the outer regions of the Jovian magnetosphere are remarkably similar to those of Earth. Bow-shock precursor electrons and ions were detected in the upstream solar wind, as at Earth. Plasma changes across the bow shock and properties of the magnetosheath electrons were much like those at Earth, indicating that similar processes are operating. A boundary layer populated by a varying mixture of solar wind and magnetospheric plasmas was found inside the magnetopause, again as at Earth. In the middle magnetosphere, large electron density excursions were detected with a 10-hour periodicity as planetary rotation carried the tilted plasma sheet past Ulysses. Deep in the magnetosphere, Ulysses crossed a region, tentatively described as magnetically connected to the Jovian polar cap on one end and to the interplanetary magnetic field on the other. In the inner magnetosphere and lo torus, where corotation plays a dominant role, measurements could not be made because of extreme background rates from penetrating radiation belt particles.

Observations at venus encounter by the plasma science experiment on mariner 10.

Preliminary results from the rearward-looking electrostatic analyzer of the plasma science experiment during the Mariner 10 encounter with Venus are described. They show that the solar-wind interaction with the planet probably involves a bow shock rather than an extended exosphere, but that this is not a thin boundary at the point where it was crossed by Mariner 10. An observed reduction in the flux of electrons with energies greater than 100 electron volts is interpreted as evidence for somne direct interaction with the exosphere. Unusual intermittent features observed downstream of the planet indicate the presence of a comet-like tail hundreds of scale lengths in length.

Comet giacobini-zinner: plasma description.

A strong interaction between the solar wind and comet Giacobini-Zinner was observed oh 11 September 1985 with the Los Alamos plasma electron experiment on the International Cometary Explorer (ICE) spacecraft. As ICE approached an intercept point 7800 kilometers behind the nucleus from the south and receded to the north, upstream phenomena due to the comet were observed. Periods of enhanced electron heat flux from the comet as well as almost continuous electron density fluctuations were measured. These effects are related to the strong electron heating observed in the cometary interaction region and to cometary ion pickup by the solar wind, respectively. No evidence for a conventional bow shock was found as ICE entered and exited the regions of strongest interaction of the solar wind with the cometary environment. The outer extent of this strong interaction zone was a transition region in which the solar wind plasma was heated, compressed, and slowed. Inside the inner boundary of the transition region was a sheath that enclosed a cold intermediate coma. In the transition region and sheath, small-scale enhancements in density were observed. These density spikes may be due to an instability associated with cometary ion pickup or to the passage of ICE through cometary ray structures. In the center of the cold intermediate coma a narrow, high-density core of plasma, presumably the developing plasma tail was found. In some ways this tail can be compared to the plasma sheet in Earth's magnetotail and to the current sheet in the tail at Venus. This type of configuration is expected in the double-lobe magnetic topology detected at the comet, possibly caused by the theoretically expected draping of the interplanetary magnetic field around its ionosphere.

Extensive water ice within Ceres' aqueously altered regolith: Evidence from nuclear spectroscopy.

The surface elemental composition of dwarf planet Ceres constrains its regolith ice content, aqueous alteration processes, and interior evolution. Using nuclear spectroscopy data acquired by NASA's Dawn mission, we determined the concentrations of elemental hydrogen, iron, and potassium on Ceres. The data show that surface materials were processed by the action of water within the interior. The non-icy portion of Ceres' carbon-bearing regolith contains similar amounts of hydrogen to those present in aqueously altered carbonaceous chondrites; however, the concentration of iron on Ceres is lower than in the aforementioned chondrites. This allows for the possibility that Ceres experienced modest ice-rock fractionation, resulting in differences between surface and bulk composition. At mid-to-high latitudes, the regolith contains high concentrations of hydrogen, consistent with broad expanses of water ice, confirming theoretical predictions that ice can survive for billions of years just beneath the surface.

Effect of ampicillin and chloramphenicol against Haemophilus influenzae.

Synergy, determined by isobolograms constructed from the minimal inhibitory concentrations of combinations of ampicillin and chloramphenicol, was observed against six of 13 ampicillin-susceptible Haemophilus influenzae type b isolates and against five of eight ampicillin-resistant strains by using a small inoculum of 10(4) colony forming units (CFU) per milliliter. Synergy occurred against nine of 13 ampicillin-susceptible and against two of eight ampicillin-resistant strains using a large inoculum of 10(7) CFU/ml. When synergy was not observed, additive effects occurred against the remainder of isolates. Additive effects were also observed against single strains of chloramphenicol-resistant, nontypeable H. influenzae and H. parainfluenzae. No antagonism was observed. These data indicate that ampicillin and chloramphenicol may be synergistic against a significant number of H. influenzae strains depending on inoculum size, but the effect is unpredictable for a given isolate. These data support the recommendation that ampicillin and chloramphenicol both be used as initial therapy for patients with suspected bacterial meningitis.

Haemophilus influenzae type b brain abscess complicating meningitis: case report.

A 7-month-old child developed beta-lactamase negative Haemophilus influenzae type b meningitis which was treated with parenteral ampicillin and chloramphenicol for two days and ampicillin for eight additional days. She was readmitted two days after discharge on the 14th day after the initial hospitalization because of a suspected relapse of meningitis. Cultures of CSF and blood yielded no growth, and therapy with ampicillin and chloramphenicol was discontinued after three days. After discharge, her fontanel became full and a large, right, frontoparietal brain abscess was found on her third admission on day 25. Pus from the abscess yielded beta-lactamase negative H influenzae type b but CSF and blood yielded no growth. The abscess resolved after needle aspiration of pus and 4 weeks of therapy with ampicillin and chloramphenicol. It is speculated that this rare complication of H influenzae meningitis arose from a focal infection in an area of brain necrosis that resulted from the initial meningitis.

Culture versus biology: children's attitudes toward thinness and fatness.

Many of the studies regarding children's acquisition of prevailing cultural concepts of physical attractiveness are flawed by small and unrepresentative samples, measurement instruments of questionable reliability and validity, and experimental designs that do not protect against bias. Additional studies in which these methodologic flaws are overcome must be carried out if we are to understand truly when and how cultural concepts of beauty are acquired. Nevertheless, the majority of the studies already done find that children acquire prevailing cultural values of beauty before adolescence and that thinness is desirable to girls considerably before puberty. It is suggested that the etiology of eating disorders and the reasons for their increasing prevalence will not be discovered by studying only clinical cases. We propose that those interested in this important health problem study children before adolescence in an attempt to learn how preoccupation with weight begins and why thinness is believed to be attractive. Once these are understood, a greater challenge will be the development and testing of interventions--be they in the schools or using the media--which can effectively prevent this public health problem. When culture and biology clash, people may suffer.

Relapse of Hemophilus influenzae type b meningitis after combined antibiotic therapy: report of a case.

Antibiotic therapy of bacterial meningitis is being reevaluated due to reports of ampicillin-resistant strains of Hemophilus influenzae type b. The infant reported had a relapse of H. influenzae type b meningitis after an excellent clinical and bacteriologic response to an initial course of combined antibiotic therapy including chloramphenicol. This relapse is postulated to be due to localized cerebral vasculitis which was not treated for a sufficient period of time during the initial course of therapy. The patient responded well to a second course of penicillin and chloramphenicol. Since the use of pencillin and chloramphenicol will be increasing, the clinician should be aware that bacteriologic relapse of H. influenzae type b meningitis may occur with chloramphenicol therapy.

A cohort study on childhood asthma admissions and readmissions.

BACKGROUND: Admissions to hospitals for childhood asthma seem to be increasing, even though admissions for other childhood conditions are decreasing. We studied admissions and readmissions for childhood asthma in Ontario in an attempt to uncover factors relating to the admission patterns. METHODS: Using the hospital discharge data from the Canadian Institute for Health Information, 28,646 children with diagnoses of asthma were identified from April 1, 1989, to March 31, 1992. RESULTS: The admission rates for asthma among children in Ontario showed a 14.8% decrease from 1987 to 1992. This decline was observed primarily in 5- to 17-year-olds. Younger children had a fourfold risk of hospital admission for asthma. In the 4 years studied, 10,427 children (36.4%) were readmitted at least once, representing 22,114 readmissions, 16,196 (73.2%) of which were for asthma. The 6-month probabilities of readmission for asthma were 20.0% (0- to 4-year-olds) and 11.7% (5- to 17-year-olds). The estimated relative risks (RRs) indicated that younger children had a significantly higher risk of readmission for asthma (RR, 1.38; 95% confidence interval, 1.30 to 1.46) or asthma-related causes (RR, 5.02; 95% confidence interval, 4.16 to 6.05). CONCLUSIONS: The observed increasing trend in admissions for asthma among children in the 1970s and 1980s leveled off in the early 1990s. The declining admission rates were largely caused by the lower admission rates among school-aged children from 5 to 17 years. The relatively high admission and readmission rates of preschool children are still a concern. Further research is necessary to examine factors that influence admissions for asthma among young children.

Ultrasonographic studies in the management of recurrent abdominal pain.

The medical records of 65 children and adolescents who had abdominal ultrasonography for the evaluation of recurrent abdominal pain were reviewed. Fifty-three subjects (81%) had normal results; in 12 cases (19%) an abnormality was detected. In no case could the pain be attributed to the abnormal finding. Furthermore, in 3 subjects, disclosure of the abnormal findings could have caused more harm than good. The role of the abdominal ultrasonographic study in the management of recurrent abdominal pain in children and adolescents is discussed.

Randomized, controlled trial comparing long-term sulfonamide therapy to ventilation tubes for otitis media with effusion.

Several studies have indicated that either the surgical insertion of ventilation tubes (VTs) or long-term treatment with sulfonamide-based antibacterials is effective in the management of otitis media with effusion (OME; otherwise known as serous otitis media, secretory otitis media, and glue ear) when compared with a no-treatment control or placebo. This controlled trial is the first to compare directly the effectiveness of these two treatments for long-standing OME. Outcome variables are treatment success rates, hearing thresholds, recurrent acute otitis media episodes, and side effects of medication or complications of VT placement. One hundred twenty-five children (aged 2.5 to 7 years) who met the usual indications for surgery (long-standing [greater than 3 months] OME and conductive hearing loss) were randomly assigned to "medical" treatment (sulfisoxazole 75 mg/kg per day for 6 months) or "surgical" treatment (bilateral insertion of VTs). Subjects underwent pure-tone audiometry (500, 1000, 2000, 4000 Hz) and otomicroscopic examination at 2, 4, 6, 12, and 18 months. A significantly greater proportion of medical subjects (67%) than surgical subjects (48%) were treatment failures at 6, 12, or 18 months (P = .0208). Surgical subjects had significantly better hearing at 2 and 4 months (P values less than .01) but not at 6, 12, and 18 months (P values greater than .2). A significantly greater proportion of surgical subjects (50%) experienced complications of treatment than did medical subjects (9%) (P less than .001). Thirty-three percent of candidates for VT placement did not require surgery when treated with a 6-month course of sulfisoxazole.(ABSTRACT TRUNCATED AT 250 WORDS)

Initial evaluation of heart murmurs: are laboratory tests necessary?

Heart murmurs, most of them innocent, are the most common reason for referrals to a pediatric cardiologist. In the evaluation of murmurs, the electrocardiogram and echocardiogram are often included. The purpose of this study was to determine the utility of these examinations in the initial assessment of heart murmurs in children and adolescents. In a prospective series of 161 patients, the clinical diagnosis of heart murmurs by a pediatric cardiologist was compared with that obtained after electrocardiogram and echocardiogram (two-dimensional, M-mode, Doppler, and color-Doppler). On the basis of the clinical diagnosis the patients were classified as having "innocent murmur," "pathologic murmur," or "possible pathologic murmur." A total of 161 patients (51% males), aged 1 month to 17 years (median 3.2 years), were studied. After electrocardiogram, no diagnosis was changed. After echocardiogram, the clinical diagnosis of innocent murmur in 109 patients changed in 2 to pathologic (small ventricular septal defect 1, small atrial septal defect 1); pathologic murmur in 46 changed to innocent in 3 and possible pathologic in 2; and possible pathologic in 6 changed to innocent in 3 and to pathologic in 2. The clinical examination by an experienced pediatric cardiologist is an accurate means of assessing newly referred patients with murmurs. The clinical examination had a sensitivity of 96%, specificity of 95%, positive predictive value of 88%, and negative predictive value of 98%. The electrocardiogram, unlikely to disclose any unsuspected heart disease, may assist in reaching the lesion-specific diagnosis when there is underlying pathology. Echocardiography, although diagnostic when heart disease is suspected, is unnecessary in pediatric patients with clinically diagnosed innocent heart murmurs.

Is childhood sexual abuse really increasing in prevalence? An analysis of the evidence.

One controversy regarding childhood sexual abuse is whether the increased rate of reported cases reflects a true increase in prevalence. In this report, data obtained in the 1970s and 1980s were compared with those of the 1940s. Using predetermined criteria for quality of information, commonality of definitions of childhood sexual abuse, and research design, the authors reviewed the Kinsey report published in 1953 and 19 prevalence studies reported in the last 10 years. Interrater reliability was .97 for each paper. In spite of differences in study designs and populations surveyed, where definitions of childhood sexual abuse were similar, the more recent studies with the strongest methodology reported prevalence figures similar to those of Kinsey in the 1940s, ie, 10% to 12% of girls younger than 14 years of age. Thus it would appear that increased reporting is due to changes in legislation and social climate rather than a true increase in prevalence. The absence of an increase in prevalence of childhood sexual abuse should not deter those interested in pursuing solid research in prevention and treatment because any childhood sexual abuse is too much.

Characteristic craniofacial appearance and brachytelephalangy in a mother and son with Kallman syndrome in the son.

We report on a mother and son with a similar facies characterized by a square forehead, small nose, telecanthus, and thin upper lip. They both had a similar metacarpal-phalangeal profile characterized by marked brachytelephalangy. They were both short in comparison to other family members, and the son had hypogonadotropic-hypogonadism and anosmia. We favor the hypothesis of a single autosomal dominant gene with variable expression of the hypogonadism and anosmia, although there are alternative explanations for the combination.

Serum gamma-glutamyl transpeptidase. Evaluation in screening of hospitalized patients.

Evaluation in screening of hospitalized patients. Am J Clin Pathol 64: 311-314, 1975. The specificity of the serum gamma-glutamyl transpepidase (GGT) was evaluated by its determination in 1,040 unselected adult inpatients. GGT was elevated in 139 (13.4%) patients, but was only rarely elevated in the absence of elevation of other enzymes in the routine chemistry profile. Of the elevations, 32.4% occurred in patients with primary hepatobiliary disease. An elevated serum GGT is a strong indicator of hepatobiliary dysfunction. However, proper interpretation of a serum GGT elevation requires correlation with clinical data and other tests.

Is bone marrow aspiration needed in acute childhood idiopathic thrombocytopenic purpura to rule out leukemia?

OBJECTIVE: To assess the prevalence of leukemia in a series of bone marrow aspiration (BMA) samples collected to confirm provisional diagnoses of acute idiopathic thrombocytopenic purpura (ITP) in children. DESIGN: A retrospective cohort. SETTING: All BMA reports at The Hospital for Sick Children, Toronto, Ontario (a tertiary care pediatric hospital), from January 1, 1984, to May 31, 1996, were reviewed. PATIENTS: Included were BMAs performed to confirm provisional diagnoses of ITP in children (6 months to 18 years of age) with "typical" contemporaneous hematologic features of ITP (platelet count, < or =50 x 10(9)/L; hemoglobin level, > or =100 g/L [6-12 months of age] or > or =110 g/L [> 1 year of age]; white blood cell count, > or =5 x 10(9)/L [6 months to 6 years of age] or > or =4 x 10(9)/L [> 6 years of age]; and neutrophil count, > or =1.5 x 10(9)/L [6 months to 6 years of age] or > or =2 x 10(9)/L [> 6 years of age]). Children with chronic ITP, thrombocytopenia-related chronic conditions, or leukemic blasts on peripheral smears were excluded. MAIN OUTCOME MEASURE: The finding of leukemia in the BMA report was chosen a priori as the primary outcome for the yield of BMA. RESULTS: Four hundred eighty-four BMAs were performed to confirm provisional diagnoses of acute childhood ITP. No diagnoses of leukemia were revealed in the 332 children with typical hematologic features of ITP. The risk of missing the diagnosis of leukemia in this setting is less than 1%. CONCLUSIONS: The yield of BMA for leukemia in this setting is low. Routine BMA is not necessary for children with typical acute ITP.