Young children and the say/mean distinction: verbatim and paraphrase recognition in narrative and nursery rhyme contexts.

Children's ability to distinguish between the text, what was said, and the intentional structure, what was meant, was interrogated by means of verbatim and paraphrase questions in two types of discourse, narratives and nursery rhymes. Three- to seven-year-olds participated (n = 119, mean age 5.1). There was an interaction between the type of discourse and the younger children's ability to separate wording from intentional structure. In the narrative form they had difficulty rejecting true paraphrases when asked to focus on wording, while in the nursery rhyme form the difficulty was accepting a true paraphrase when asked to focus on intention.

Between realism and nominalism: learning to think about names and words.

Some of the factors that influence our understanding of the nature of names and words were investigated. Participants (from kindergarten, 2nd, 4th, and 6th grades, and a university undergraduate class) were told a series of brief narratives thematizing the relation between objects and names, after which they were asked questions about the origins and changeability of names and words. Responses were coded as either realist (i.e., viewing names as intrinsic properties of objects) or nominalist (i.e., understanding names and words as arbitrary social conventions). By Grade 2, the children showed a significant increase in nominalist thinking, but this was not a universal development among the participants. Many adults expressed views that did not reflect a strictly nominalist understanding of words and names. Furthermore, the use of nominalist and realist models was influenced by various social-discursive factors including the type of object being named, the type of name being asked about, and the participant's prior experience with the name. It is argued that linguistic (especially literate) experiences play a crucial role in developing a nominalist understanding of names and words.

Multiple WW domains, but not the C2 domain, are required for inhibition of the epithelial Na+ channel by human Nedd4.

The epithelial Na+ channel (ENaC) absorbs Na+ across the apical membrane of epithelia. The activity of ENaC is controlled by its interaction with Nedd4; mutations that disrupt this interaction increase Na+ absorption, causing an inherited form of hypertension (Liddle's syndrome). Nedd4 contains an N-terminal C2 domain, a C-terminal ubiquitin ligase domain, and multiple WW domains. The C2 domain is thought to be involved in the Ca2+-dependent localization of Nedd4 at the cell surface. However, we found that the C2 domain was not required for human Nedd4 (hNedd4) to inhibit ENaC in both Xenopus oocytes and Fischer rat thyroid epithelia. Rather, hNedd4 lacking the C2 domain inhibited ENaC more potently than wild-type hNedd4. Earlier work indicated that the WW domains bind to PY motifs in the C terminus of ENaC. However, it is not known which WW domains mediate this interaction. Glutathione S-transferase-fusion proteins of WW domains 2-4 each bound to alpha, beta, and gammaENaC in vitro. The interactions were abolished by mutation of two residues. WW domain 3 (but not the other WW domains) was both necessary and sufficient for the binding of hNedd4 to alphaENaC. WW domain 3 was also required for the inhibition of ENaC by hNedd4; inhibition was nearly abolished when WW domain 3 was mutated. However, the interaction between ENaC and WW domain 3 alone was not sufficient for inhibition. Moreover, inhibition was decreased by mutation of WW domain 2 or WW domain 4. Thus, WW domains 2-4 each participate in the functional interaction between hNedd4 and ENaC in intact cells.

Gating induces a conformational change in the outer vestibule of ENaC.

The epithelial Na(+) channel (ENaC) is comprised of three homologous subunits (alpha, beta, and gamma). The channel forms the pathway for Na(+) absorption in the kidney, and mutations cause disorders of Na(+) homeostasis. However, little is known about the mechanisms that control the gating of ENaC. We investigated the gating mechanism by introducing bulky side chains at a position adjacent to the extracellular end of the second membrane spanning segment (549, 520, and 529 in alpha, beta, and gammaENaC, respectively). Equivalent "DEG" mutations in related DEG/ENaC channels in Caenorhabditis elegans cause swelling neurodegeneration, presumably by increasing channel activity. We found that the Na(+) current was increased by mutagenesis or chemical modification of this residue and adjacent residues in alpha, beta, and gammaENaC. This resulted from a change in the gating of ENaC; modification of a cysteine at position 520 in betaENaC increased the open state probability from 0. 12 to 0.96. Accessibility to this side chain from the extracellular side was state-dependent; modification occurred only when the channel was in the open conformation. Single-channel conductance decreased when the side chain contained a positive, but not a negative charge. However, alterations in the side chain did not alter the selectivity of ENaC. This is consistent with a location for the DEG residue in the outer vestibule. The results suggest that channel gating involves a conformational change in the outer vestibule of ENaC. Disruption of this mechanism could be important clinically since one of the mutations that increased Na(+) current (gamma(N530K)) was identified in a patient with renal disease.

Elevated blood lead levels and blood lead screening among US children aged one to five years: 1988-1994.

OBJECTIVES: To estimate the proportion of children 1 to 5 years of age who received blood lead testing during 1988-1994 and to assess whether predictors of testing coincided with predictors of elevated blood lead levels. DESIGN: Cross-sectional analysis of data from the Third National Health and Nutrition Examination Survey. Participants. US children 1 to 5 years of age. Outcome Measures. Prevalence of blood lead testing and elevated blood lead levels among children 1 to 5 years of age and odds ratios for factors predicting blood lead testing and elevated blood lead levels. RESULTS: Overall, 6.3% had elevated blood lead levels and 10.2% had undergone previous blood lead tests. Being of minority race/ethnicity, living in an older home, residing in the Northeast or Midwest regions of the United States, being on Medicaid, having a head of household with <12 years of education, and having a history of anemia were significant factors in both models. Additional independent risk factors for an elevated blood lead level included being sampled in phase 1 of the survey, being 1 to 2 years of age, not having a regular doctor, and being sampled during the summer months. Additional independent correlates of a previous blood lead test included having moved less than twice in one's lifetime, having a female head of household, and having parents whose home language was English. Of an estimated 564 000 children 1 to 5 years of age who had elevated blood lead levels and no previous screening test in 1993, 62% were receiving Medicaid, 40% lived in homes built before 1946, and 34% were black, non-Hispanic. CONCLUSIONS: Lead screening was more frequent among children with risk factors for lead exposure. However, among children with elevated blood lead levels, only one third had been tested previously. In 1993 an estimated 564 000 children 1 to 5 years of age had elevated blood lead levels but were never screened. Physicians should screen Medicaid-eligible children and should follow state or local health department recommendations about identifying and screening other at-risk children. In areas where no health department guidelines exist, physicians should screen all children or screen based on known risk factors.

A pore segment in DEG/ENaC Na(+) channels.

DEG/ENaC Na(+) channels have diverse functions, including Na(+) absorption, neurotransmission, and sensory transduction. The ability of these channels to discriminate between different ions is critical for their normal function. Several findings suggest that DEG/ENaC channels have a pore structure similar to K(+) channels. To test this hypothesis, we examined the accessibility of native and introduced cysteines in the putative P loop of ENaC. We identified residues that span a barrier that excludes amiloride as well as anionic and large methanethiosulfonate reagents from the pore. This segment contains a structural element ((S/G)CS) involved in selectivity of ENaC. The results are not consistent with predictions from the K(+) channel pore, suggesting that DEG/ENaC Na(+) channels have a novel pore structure.

Chinese children's understanding of false beliefs: the role of language.

The present study investigated the universality of the early development of young children's understanding and representation of false beliefs, and specifically, the effect of language on Chinese-speaking children's performance in false belief tasks under three between-subjects conditions. The three conditions differed only in the belief verb that was used in probe questions regarding one's own or another person's beliefs namely the Chinese verbs, xiang, yiwei, and dang. While the three words are all appropriate to false beliefs, they have different connotations regarding the likelihood of a belief being false, with xiang being more neutral than either yiwei or dang. Experiment 1 involved thirty-five Chinese-speaking adults who responded to false belief tasks to be used in Experiment 2 in order both to establish an adult comparison and to obtain empirical evidence regarding how Chinese-speaking adults use the three belief verbs to describe different false belief situations. In Experiment 2, 188 three-, four-, and five-year-old Chinese-speaking children participated in three false belief tasks. They were asked to report about an individual's false belief when either xiang, yiwei, or dang was used in the probe question. Results revealed a rapid developmental pattern in Chinese-speaking children's understanding of false belief, which is similar to that found with Western children. In addition, children performed significantly better when yiwei and dang, which connote that the belief referred to may be false, were used in belief questions than when xiang, the more neutral verb, was used. This finding suggests an important role of language in assessing children's understanding of belief and false belief.

Copper in drinking water, Nebraska, 1994.

In 1993, the levels of copper (Cu) in much of Nebraska's drinking water exceeded the U.S. Environmental Protection Agency's (EPA) action level of 1.3 mg/L. To determine the association of copper with gastrointestinal (GI) illness in August 1994 the authors interviewed persons living in households with 1993 Cu levels > 3 mg/L (51 households), 2-3 mg/L (54 households), and < 1.3 mg/L (43 households). Cases were defined as persons who had experienced the rapid onset of vomiting or nausea with abdominal pain during the preceding two weeks. To validate their exposure index, the authors immediately resampled drinking water in the households of 25 cases and 27 controls matched for age. Reassessment in December 1994 of the exposure and case status of the original cohort showed no association between copper in drinking water in 1993 and case status in 1994. The risk of GI illness seemed no greater with Cu > 3 mg/L (RR = 1.03; 95% CI = 0.43, 2.49) or 2-3 mg/L (RR = 0.50; 95% CI = 0.18, 1.41) than with Cu < 1.3 mg/L. The 1993 Cu concentrations could not be reproduced in August 1994; resampling in December 1994 again showed no association between GI illness and Cu exposure (RR > 1.3-2.9 mg/L, < or = 1.3 mg/L = 0.25, 95% CI = 0.10, 0.64, and RR > or = 3.0 mg/L, < or = 1.3 mg/L = 0.36, 95% CI = 0.09, 1.49).

Acute pulmonary hemorrhage in infants associated with exposure to Stachybotrys atra and other fungi.

BACKGROUND: A geographic cluster of 10 cases of pulmonary hemorrhage and hemosiderosis in infants occurred in Cleveland, Ohio, between January 1993 and December 1994. STUDY DESIGN: This community-based case-control study tested the hypothesis that the 10 infants with pulmonary hemorrhage and hemosiderosis were more likely to live in homes where Stachybotrys atra was present than were 30 age- and ZIP code-matched control infants. We investigated the infants' home environments using bioaerosol sampling methods, with specific attention to S atra. Air and surface samples were collected from the room where the infant was reported to have spent the most time. RESULTS: Mean colony counts for all fungi averaged 29 227 colony-forming units (CFU)/m3 in homes of patients and 707 CFU/m3 in homes of controls. The mean concentration of S atra in the air was 43 CFU/m3 in homes of patients and 4 CFU/m3 in homes of controls. Viable S atra was detected in filter cassette samples of the air in the homes of 5 of 9 patients and 4 of 27 controls. The matched odds ratio for a change of 10 units in the mean concentration of S atra in the air was 9.83 (95% confidence interval, 1.08-3 X 10(6)). The mean concentration of S atra on surfaces was 20 X 10(6) CFU/g and 0.007 x 10(6) CFU/g in homes of patients and controls, respectively. CONCLUSION: Infants with pulmonary hemorrhage and hemosiderosis were more likely than controls to live in homes with toxigenic S atra and other fungi in the indoor air.

The relation between acquisition of a theory of mind and the capacity to hold in mind.

Building on earlier work by Pascual-Leone (1970) and Case (1985), Olson (1989; 1993) set out a theory showing how a series of incremental changes in capacity for "holding in mind" could account, in part, for children's acquisition of a theory of mind. Following Piaget (1951) infants were said to employ schemata for maintaining relations with objects and events in the presence of those events. At about 18 months children became capable of holding in mind an object so as to free the perceptual system to perceive a second object and form a relation between the two, allowing for what Piaget called the "symbolic function" and what Olson described as predication. At around 4 years, the period examined in the present study, children were said to acquire the ability to represent that predicative relation as a belief or as true or false. That was the stage at which children were said to possess a theory of mind. The present study tested the hypothesized relation between development of a theory of mind and increasing computational resources. Three-, four-, and five-year-old children's performance on a pair of theory of mind tasks was compared with that on a pair of dual processing tasks designed on the basis of Baddeley's (1986) model of working memory. The resulting correlations, as high as r = .64 between the tasks, suggest that changes in capacity to hold in mind allow the expression of, and arguably the formation of, a theory of mind.

Reexamination of epidemic asthma in New Orleans, Louisiana, in relation to the presence of soy at the harbor.

Epidemic asthma occurred in New Orleans, Louisiana, in the 1950s and 1960s, but its causes were never fully understood. Subsequently, similar outbreaks of epidemic asthma in Barcelona, Spain, were shown to be caused by the release of soy dust at the harbor. To investigate whether airborne soy dust may have contributed to epidemic asthma in New Orleans, the authors examined historical data on vessel cargo from the New Orleans harbor together with data on emergency department visits for asthma, for the period from 1957 through 1968. Days on which there were 64 or more visits for asthma were twice as likely to have occurred on days when a vessel carrying soy was at the harbor (odds ratio (OR) = 2.3, 95% confidence interval (CI) 1.5-3.3). The association was stronger when the maximum wind speed was less than 12 miles/hour (19.3 km/hour) (OR = 4.0, 95% CI 2.1-7.7) and strongest when wind speeds were low and the prevailing winds were from the south or southwest, the direction of two grain elevators from the hospital (OR = 6.7, 95% CI 1.5-46.7). Various temporal and climatic factors that had been associated with the occurrence of asthma outbreaks did not appear to be important confounding factors. The association was specific to soy cargo; no association was observed between asthma-epidemic days and the presence of either wheat or corn in vessels at the harbor. The results of this analysis provide further evidence that ambient soy dust is very asthmogenic and that asthma morbidity in a community can be influenced by exposures in the ambient atmosphere.

A longitudinal study of ambient air pollutants and the lung peak expiratory flow rates among asthmatic children in Hungary.

BACKGROUND: We conducted this study in Budapest, Hungary, to better characterize the effects of exposure to ambient air pollutants on the lung function of asthmatic children. METHODS: The 60 study participants were 9-14 years old, had physician-diagnosed asthma, and were symptomatic during the previous year. Their ambient air pollutant exposures to total suspended particulates (TSP) and sulphur dioxide (SO2) were estimated from measurements made at the air monitor nearest their residence. We used analysis of variance and a fixed-effects model to assess the impact of the pollutants upon their morning and evening peak expiratory flow rates (PEFR) from 13 September to 5 December 1993. RESULTS: Total suspended particulates and SO2 concentrations exceeded World Health Organization guideline limits on several days. Pollutant concentrations and PEFR increased during the study period. After adjusting for temperature, humidity, weekend/weekday, and the time trend, we found no consistent association between air pollutant concentrations and PEFR. CONCLUSIONS: Fall to winter seasonal changes had a large influence on PEFR and may have overshadowed the effects of the air pollutants during the study period. Seasonal influences should be carefully considered when planning future studies.

Towards a psychology of literacy: on the relations between speech and writing.

A variety of graphic systems have been developed for preserving and communicating information, among them pictures, charts, graphs, flags, tartans and hallmarks. Writing systems which constitute a species of these graphic systems are distinctive in that they bear a direct relation to speech; in this paper it is argued that writing serves as a model for various properties of speech including sentences, words and for alphabets, phonemes. On this view, the history of writing and the acquisition of literacy are less matters of learning how to transcribe speech than a matter of learning to hear and think about one's own language in a new way. A number of lines of evidence are advanced to support the "model" view and the conclusion that literacy contributes to conceptual structure rather than merely reporting it.

Reflecting on scientific thinking: children's understanding of the hypothesis-evidence relation.

3 experiments were carried out to examine children's understanding of the role of covariation evidence in hypothesis formation. Previous research suggested that it is not until 8 to 11 years of age that children begin to understand how a given pattern of covariation supports a particular hypothesis about which factor is causally responsible for an observed effect. Experiments 1 to 3 employed a different (fake evidence) technique than previous research and showed that by 6 years of age most children understand how evidence would lead a story character to form a different hypothesis than the subject's own. Experiment 3 showed that most 6- and young 7-year-olds understand how a character's future actions (e.g., choice of an object) and predictions of future outcomes depend on the hypothesis he or she holds.

Surveillance for diabetes mellitus--United States, 1980-1989.

PROBLEM/CONDITION: In the United States, diabetes mellitus is the most important cause of lower-extremity amputation and end-stage renal disease; the major cause of blindness among working-age adults; a major cause of disability, premature mortality, congenital malformations, perinatal mortality, and health-care costs; and an important risk factor for the development of many other acute and chronic conditions (e.g., diabetic ketoacidosis, ischemic heart disease, stroke). Surveillance data describing diabetes and its complications are critical to increasing recognition of the public health burden of diabetes, formulating health-care policy, identifying high-risk groups, developing strategies to reduce the burden of this disease, and evaluating progress in disease prevention and control. REPORTING PERIOD COVERED: In this report, data are summarized from CDC's diabetes surveillance system; trends in diabetes and its complications are evaluated by age, sex, and race for the years 1980-1989. DESCRIPTION OF SYSTEM: CDC has established an ongoing and evolving surveillance system to analyze and compile periodic, representative data on the disease burden of diabetes and its complications in the United States. Data sources currently include vital statistics, the National Health Interview Survey, the National Hospital Discharge Survey, and Medicare claims data for end-stage renal disease. RESULTS AND INTERPRETATION: In 1989, approximately 6.7 million persons in the United States reported that they had diabetes mellitus, and a similar number probably had this disabling chronic disease without being aware of it. The disease burden of diabetes and its complications is large and is likely to increase as the population grows older. Effective primary, secondary, and tertiary prevention strategies are needed, and these efforts need to be intensified among groups at highest risk, including blacks. Important gaps exist in periodic and representative data for describing the disease burden. ACTIONS TAKEN: CDC is assisting diabetes control programs in 26 states and one territory. These programs attempt to reduce the burden of diabetes by preventing blindness, lower-extremity amputations, cardiovascular disease, and adverse outcomes of pregnancy among persons with diabetes. Because of important limitations in measuring the burden of diabetes, CDC is exploring sources of surveillance data for blindness, adverse outcomes of pregnancy, and the public health burden of diabetes among minority groups.

Methods for analysing county-level mortality rates.

The identification of counties burdened by exceptionally high rates of mortality is a fundamental step in the development of state-based intervention and prevention strategies. However, the estimation of rates from small geographic areas presents special problems, especially for rare events. This paper compares the use of crude and age-standardized rates to the use of Poisson regression models and empirical Bayes models for analysing county-level mortality rates. The results demonstrate both practical and heuristic advantages of the empirical Bayes models. Age-standardized rates adjust for differences in age structure among countries but are vulnerable to extreme variability in county age-specific rates. In our example--an analysis of diabetes mortality rates--Poisson regression did not improve the variability of estimated county-level rates. Adjusted empirical Bayes estimates dramatically shrink the observed rates while preserving some separation of the counties with extreme rates. Also, empirical Bayes estimates of rates for countries with no observed deaths are shrunk close to the prior mean.

Trends in diabetes and diabetic complications, 1980-1987.

OBJECTIVE: Although diabetes is a major source of morbidity and mortality in the United States, only recently has a unified national surveillance system begun to monitor trends in diabetes and diabetic complications. RESEARCH DESIGN AND METHODS: We established a diabetes surveillance system using data for 1980-1987 from vital records, the National Health Interview Survey, the National Hospital Discharge Survey, and the Health Care Financing Administration's records to examine trends in the prevalence and incidence of diabetes, diabetes mortality, hospitalizations, and diabetic complications. RESULTS: From 1980 through 1987, the number of individuals known to have diabetes increased by 1 million--to 6.82 million. Age-standardized prevalence for diabetes increased 9% during this period, from 25.4 to 27.6/1000 U.S. residents (P = 0.03). The incidence of diabetes increased among women (P = 0.003), particularly among those greater than 65 yr old (P = 0.02). Age-standardized mortality rates (for diabetes as either an underlying or contributing cause) per 100,000 individuals with diabetes declined 12%, from 2350 to 2066. Annual mortality rates from stroke (as an underlying cause and diabetes as a contributing cause) and diabetic ketoacidosis declined 29% (P = 0.003) and 22% (P less than 0.001), respectively. During these 8 yr, hospitalization rates for major CVD and stroke (as the primary diagnoses and diabetes as a secondary diagnosis) increased 34% (P = 0.006) and 38% (P = 0.01), respectively. Also during this period, hospitalization rates increased 21% for diabetic ketoacidosis (P = 0.01) and 29% for lower-extremity amputations (P = 0.06). From 1982 through 1986, treatment for end-stage renal disease related to diabetes increased greater than 10% each year (P less than 0.001). The prevalence of diagnosed diabetes was nearly twice as high in blacks as in whites (P = 0.04). Blacks also had increased rates of lower-extremity amputation (P = 0.02), diabetic ketoacidosis (P less than 0.001), and end-stage renal disease (P = 0.01). CONCLUSIONS: Diabetes surveillance data will be useful in planning, targeting, and evaluating public health efforts designed to prevent and control diabetes and its complications.

Hospitalization for pregnancy complications, United States, 1986 and 1987.

OBJECTIVE: The purpose of our analysis was to provide a national overview of the magnitude of the public health burden associated with inpatient care for pregnancy complications. STUDY DESIGN: We analyzed data from the National Hospital Discharge Survey for 1986 and 1987. We calculated ratios of hospitalizations for pregnancy complications for every 100 hospitalizations involving a birth. Standard errors for these ratios were calculated with RATIOEST, and relative ratios with 95% confidence intervals were calculated for subgroups of interest. RESULTS: We found that for every 100 hospitalizations involving a birth, there were 22.2 nondelivery hospitalizations for pregnancy complications (14.6 antenatal complications, 7.6 pregnancy loss complications). These ratios were higher for black than for white women (relative ratio 1.4, 95% confidence interval 1.2 to 1.6). The effects of marital status, age, and insurance coverage differed between black and white women, and mean length of stay was longer for black than for white women. CONCLUSION: Hospitalization for pregnancy complications is far more common than is widely appreciated and is more frequent among black than white women.

National trends in the incidence of abruptio placentae, 1979-1987.

Premature separation of the normally implanted placenta is a serious complication of pregnancy and a leading cause of maternal and perinatal morbidity and mortality. Using data from the National Hospital Discharge Survey, we estimated rates of abruptio placentae in the United States for the years 1979-1987 and examined the association of this condition with several demographic risk factors and coexisting obstetric conditions. In 1987, the national rate was 11.5 cases per 1000 deliveries. The rate of abruptio placentae increased significantly between the years 1979-1987 among women of all racial groups. The increase in the rate of placental abruption occurred mainly among women under the age of 25, unmarried women, and women on Medicaid compared with those who had private insurance. Women with placental abruption were 54 times more likely to have coagulopathies and 11 times more likely to have stillbirths than those without placental abruption. Twin gestations, preterm premature rupture of membranes, chorioamnionitis, chronic hypertension, and preeclampsia/eclampsia were also associated with placental abruption. Although the cause for the increase in the incidence of abruptio placentae is not known, most of the increase occurred among women likely to be financially and socially disadvantaged.