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Explaining errors in children's questions.

The ability to explain the occurrence of errors in children's speech is an essential component of successful theories of language acquisition. The present study tested some generativist and constructivist predictions about error on the questions produced by ten English-learning children between 2 and 5 years of age. The analyses demonstrated that, as predicted by some generativist theories [e.g. Santelmann, L., Berk, S., Austin, J., Somashekar, S. & Lust. B. (2002). Continuity and development in the acquisition of inversion in yes/no questions: dissociating movement and inflection, Journal of Child Language, 29, 813-842], questions with auxiliary DO attracted higher error rates than those with modal auxiliaries. However, in wh-questions, questions with modals and DO attracted equally high error rates, and these findings could not be explained in terms of problems forming questions with why or negated auxiliaries. It was concluded that the data might be better explained in terms of a constructivist account that suggests that entrenched item-based constructions may be protected from error in children's speech, and that errors occur when children resort to other operations to produce questions [e.g. Dabrowska, E. (2000). From formula to schema: the acquisition of English questions. Cognitive Liguistics, 11, 83-102; Rowland, C. F. & Pine, J. M. (2000). Subject-auxiliary inversion errors and wh-question acquisition: What children do know? Journal of Child Language, 27, 157-181; Tomasello, M. (2003). Constructing a language: A usage-based theory of language acquisition. Cambridge, MA: Harvard University Press]. However, further work on constructivist theory development is required to allow researchers to make predictions about the nature of these operations.

Child↗

Adjusted Clinical Groups (ACGs) explain the utilization of primary care in Spain based on information registered in the medical records: a cross-sectional study.

BACKGROUND: Previous studies have shown the validity of Adjusted Clinical Groups (ACGs) in the primary care setting, but the absence of administrative databases is a problem for the implementation of this system. OBJECTIVES: To assess the validity of physicians' notes in computerized clinical records for the implementation of ACGs, and to determine the ability of the ACGs system to explain the use of primary care resources in real conditions of the daily practice. RESEARCH DESIGN: Cross-sectional study. SUBJECTS: All patients who were continuously assigned to 56 physicians from public primary health care centers in the Bizkaia Basque Country (Spain) over at least a 6-month period were included. MEASURES: Patients were classified by means of the ACGs system using the ICD-9-CM diagnostic codes according to three scenarios: (1) those annotated by the physicians in the computerized medical record, (2) codification of computerized medical records diagnoses by the research team, and (3) computerized medical records diagnoses complemented by hospital discharge codes. RESULTS: The ACGs system explained more than 50% of the variance in visits made to primary care physicians, 25-40% of prescriptions, 25-30% of referrals and requests of laboratory tests, and 14-16% of radiographs. The coefficients of determination remained almost invariable after the addition of hospital diagnoses or correction of coding errors. Fifty-two physicians (93%) registered their patients' diagnosis quite acceptably, whereas only 29 (52%) included this datum in the prescriptions. CONCLUSIONS: The ACGs system is a useful tool to explain the use of primary care services in a national health care system within the European Union. The implementation of ACGs from the physician's annotations in the computerized medical records is feasible.

Adolescent↗

Two-rung model of a left-handed beta-helix for prions explains species barrier and strain variation in transmissible spongiform encephalopathies.

In this study, a new beta-helical model is proposed that explains the species barrier and strain variation in transmissible spongiform encephalopathies. The left-handed beta-helix serves as a structural model that can explain the seeded growth characteristics of beta-sheet structure in PrP(Sc) fibrils. Molecular dynamics simulations demonstrate that the left-handed beta-helix is structurally more stable than the right-handed beta-helix, with a higher beta-sheet content during the simulation and a better distributed network of inter-strand backbone-backbone hydrogen bonds between parallel beta-strands of different rungs. Multiple sequence alignments and homology modelling of prion sequences with different rungs of left-handed beta-helices illustrate that the PrP region with the highest beta-helical propensity (residues 105-143) can fold in just two rungs of a left-handed beta-helix. Even if no other flanking sequence participates in the beta-helix, the two rungs of a beta-helix can give the growing fibril enough elevation to accommodate the rest of the PrP protein in a tight packing at the periphery of a trimeric beta-helix. The folding of beta-helices is driven by backbone-backbone hydrogen bonding and stacking of side-chains in adjacent rungs. The sequence and structure of the last rung at the fibril end with unprotected beta-sheet edges selects the sequence of a complementary rung and dictates the folding of the new rung with optimal backbone hydrogen bonding and side-chain stacking. An important side-chain stack that facilitates the beta-helical folding is between methionine residues 109 and 129, which explains their importance in the species barrier of prions. Because the PrP sequence is not evolutionarily optimised to fold in a beta-helix, and because the beta-helical fold shows very little sequence preference, alternative alignments are possible that result in a different rung able to select for an alternative complementary rung. A different top rung results in a new strain with different growth characteristics. Hence, in the present model, sequence variation and alternative alignments clarify the basis of the species barrier and strain specificity in PrP-based diseases.

Amino Acid Sequence↗

An international study comparing the effect of medically explained and unexplained somatic symptoms on psychosocial outcome.

OBJECTIVE: Cross-sectional studies show an association between somatic symptoms and psychiatric morbidity in primary care. However, medically explained and unexplained symptoms have been considered separately as distinct and unrelated. In addition, data on outcome in primary care are equivocal. We compare the effect of both constructs (medically explained and unexplained symptoms) on psychiatric morbidity and disability (social and physical) at 1 year follow-up. METHOD: Of 5447 patients presenting for primary care in 14 countries, 3201 participants were followed up (72% compliance). We measured physical, psychiatric, and social status using standardised instruments. RESULTS: Patients with five or more somatic symptoms had increased psychosocial morbidity and physical disability at follow-up, even after controlling for confounders such as sociodemographics and recognition or treatment by general practitioners. There was little difference in outcome between medically explained and unexplained symptoms. CONCLUSIONS: Somatic symptoms-irrespective of aetiology-are associated with adverse psychosocial and functional outcome in diverse cultures.

Adolescent↗

The impact of the transmission dynamics of the HIV/AIDS epidemic on sexual behaviour: a new hypothesis to explain recent increases in risk taking-behaviour among men who have sex with men.

Increases in sexually transmitted infections and related high-risk behaviours have been reported among men who have sex with men (MSM) in industrialised countries when effective antiretroviral therapy against HIV infection has become widely available, in the mid-nineties. The reasons for these increases are not fully understood and often conflicting. Prevention fatigue, relapses to unsafe sex, as well as optimism toward the risk of developing AIDS among people living with HIV are not unique to the era of antiretroviral therapy (ART). This has led researchers to highlight the need to investigate other potential reasons that could explain the increase in high-risk taking following the ART introduction. We put forward the hypothesis that the change in the transmission dynamics of the HIV/AIDS epidemic before and after the introduction of ART has contributed to this change in high-risk behaviour. It is suggested that a decline in sexual risk activities has occurred at the population-level following the initial spread of the HIV/AIDS epidemic because AIDS mortality and severe morbidity disproportionately depleted the pool of high-risk taking individuals. As a result, non-volitional changes may have occurred at the individual-level over time because the depletion of this pool of high-risk individuals made it more difficult for the remaining high-risk taking individuals to find partners to engage in risky sex with. Following its introduction, ART has facilitated the differential replenishment of the pool of individuals willing to engage in high-risk taking behaviours because ART reduces AIDS mortality, and morbidity. Consequently, high-risk taking individuals who had previously reduced their level of risky sex non-volitionally (i.e., as a result of the reduced availability of high-risk partners) were able to resume their initial high-risk practices as the pool of high-risk taking individuals replenished over time. Thus, a fraction of the recently reported increase in high-risk sexual activities may be secondary to the fact that those MSM who were unable to engage in their desired high-risky sexual activities (because of reduced availability) are now able to revert to them as the availability of men willing to engage in risky sexual behaviours increases partly due to ART. Therefore, we suggest that a fraction of the changes in individual behaviour are non-volitional and can be explained by a change in "sexual partner availability" due to the transmission dynamics of HIV/AIDS before and after ART. The hypothesis is formulated and explained using simple social network diagrams and the Theory of Planned Behaviour. We also discuss the implication of this hypothesis for HIV prevention.

Acquired Immunodeficiency Syndrome↗

Madness explained: why we must reject the Kraepelinian paradigm and replace it with a 'complaint-orientated' approach to understanding mental illness.

This article is a synopsis of the argument outlined in my book Madness explained: Psychosis and human nature, in which I describe a new paradigm (which might be called a 'complaint-orientated' approach) for understanding the psychotic disorders, the most disabling forms of psychiatric illness. Despite extensive efforts to study the genetics, pathophysiology and neuropsychology of the psychoses, replicable findings have been rare. I argue that this is because the phenomena concerned have been poorly defined. Since the end of the 19th century, research into the psychoses has been dominated by the system of classification first proposed by the German psychiatrist Emil Kraepelin, which assumes that the severe mental illnesses fall into discrete types such as 'schizophrenia' and 'manic depression', and that there is a clear dividing line between madness and normal functioning. However, Kraepelinian diagnoses fail all empirical tests of their validity. For example, they do not identify patients with common symptoms, with common aetiologies, who respond to specific treatments. I suggest that we therefore need to abandon psychiatric diagnoses altogether and must instead attempt to explain the specific complaints ('symptoms') that patients bring to our attention. These include hallucinations, delusional beliefs, thought and communication disorders, which are much more widely experienced than was previously thought (for example, about 10% of the population have experienced hallucinations). I show that recent psychological research has revealed much about the mechanisms underlying each of these complaints. For example, auditory hallucinations occur when the individual mistakes inner speech for an external stimulus, and delusions appear to be the product of abnormal inferential processes. The new approach has implications for aetiology. For example, researchers working within the Kraepelinian paradigm have often assumed that the psychoses are endogenous. However, there is compelling evidence that the risk of experiencing psychotic complaints is influenced by adverse environmental factors such as insecure attachment relations and exposure to sexual and other kinds of trauma. These associations are relatively easy to understand once the psychological mechanisms leading to specific complaints are known. When all of the psychotic complaints have been explained, there will be no 'schizophrenia' or 'manic depression' left behind awaiting explanation. The approach that I advocate is not only more scientific than the Kraepelinian approach, but also more humane. In contrast to the Kraepelinian approach, which has encouraged disrespect for patients' experiences, it encourages us to treat patients as rational agents and to take what they say seriously.

Cognition↗

Queuing theory under competitive social foraging may explain a mathematical equivalence of delay and probability in impulsive decision-making.

Intertemporal and probabilistic decision-making has been studied in psychiatry, ecology, and neuroeconomics. Because drug addicts and psycopaths often make risky decisions (e.g., drug misuse and aggression), investigation into types of impulsivity in intertemporal and probabilistic choices (delay and probability discounting) are important for psychiatric treatments. Studies in behavioral ecology proposed that delay and probability discounting are mediated by the same psychological process, because a decrease in probability of winning corresponds to an increase in delay until winning. According to this view, odds-against winning (=1/p-1) in probabilistic choice corresponds to delay in intertemporal choice. This hypothesis predicts that preference of gambling (low degree of probability discounting) may be associated with patience, rather than impulsivity or impatience, in intertemporal choice (low degree of delay discounting). However, recent empirical evidence in psychiatric research employing pathological gamblers indicates that pathological gamblers are impulsive in intertemporal choice (high degrees of delay discounting). However, a hyperbolic discounting function (usually adopted to explain intertemporal choice) with odds-against (instead of delay) explain experimental data in probabilistic choice dramatically well. Therefore, an alternative explanation is required for the hypothetical equivalence of odds-against to delay. We propose that queuing theory (often adopted for analyzing computer network traffic) under a competitive social foraging condition may explain the equivalence. Our hypothesis may help understand impulsivity of psychiatrics in social behavior (e.g., aggression and antisocial behavior) in addition to non-social impulsivity in reward-seeking (e.g., substance misuse).

Behavior, Addictive↗

Bitter taste markers explain variability in vegetable sweetness, bitterness, and intake.

Intake of vegetables falls short of recommendations to lower risk of chronic diseases. Most research addresses bitterness as a sensory deterrent to consuming vegetables. We examined bitter and sweet sensations from vegetables as mediators of vegetable preference and intake as well as how these tastes vary with markers of genetic variation in taste (3.2 mM 6-n-propylthiouracil bitterness) and taste pathology (1.0 mM quinine bitterness, chorda tympani nerve relative to whole mouth). Seventy-one females and 39 males (18-60 years) reported prototypical tastes from and preference for Brussels sprouts, kale and asparagus as well as servings of vegetables consumed, excluding salad and potatoes. Intensity and hedonic ratings were made with the general Labeled Magnitude Scale. Data were analyzed with multiple linear regression and structural equation modeling. Vegetable sweetness and bitterness were independent predictors of more or less preference for sampled vegetables and vegetable intake, respectively. Those who taste PROP as most bitter also tasted the vegetables as most bitter and least sweet. The spatial pattern of quinine bitterness, suggestive of insult to chorda tympani taste fibers, was associated with less bitterness and sweetness from vegetables. Via structural equation modeling, PROP best explained variability in vegetable preference and intake via vegetable bitterness whereas the quinine marker explained variability in vegetable preference and intake via vegetable bitterness and sweetness. In summary, bitterness and sweetness of sampled vegetables varied by taste genetic and taste function markers, which explained differences in preference for vegetables tasted in the laboratory as well as overall vegetable intake outside the laboratory.

Adolescent↗

Current and lifetime exposure to working conditions. Do they explain educational differences in subjective health?

Previous research has shown that the association between education and health is partly mediated by working conditions. So far, most studies fail to take into account working careers and instead focus on working conditions at one point in time. This study examines the extent to which current and lifetime exposure to working conditions differ between educational groups, and whether taking into account lifetime exposure rather than current exposure improves our understanding of educational differences in health. A representative sample of the Dutch population (n = 1561) with retrospective information about working careers shows that lower educated men are significantly more exposed to adverse working conditions than higher educated men. These differences increase over the life course. Among women there are relatively small educational differences in exposure. Lifetime exposure to adverse working conditions explains a significant part (a third) of the health differences between the highest and lowest educated men. Moreover, measurements of lifetime exposure to working conditions offer a better explanation for educational differences in health than measurements of current exposure. Among women, only relative lifetime exposure to working conditions can explain a small part of the educational differences in health, while current and absolute lifetime exposure do not explain these differences.

Adult↗

Explaining US racial/ethnic disparities in health declines and mortality in late middle age: the roles of socioeconomic status, health behaviors, and health insurance.

Pervasive health disparities continue to exist among racial/ethnic minority groups, but the factors related to these disparities have not been fully elucidated. We undertook this prospective cohort study to determine the independent contributions of socioeconomic status (SES), health behaviors, and health insurance in explaining racial/ethnic disparities in mortality and health declines. Our study period was 1992-1998, and our study population consists of a US nationally representative sample of 6286 non-Hispanic whites (W), 1391 non-Hispanic blacks (B), 405 Hispanics interviewed in English (H/E), and 318 Hispanics interviewed in Spanish (H/S), ages 51-61 in 1992 in the Health and Retirement Study. The main outcome measures were death; major decline in self-reported overall health (SROH); and combined outcome of death or major decline in SROH. Crude mortality rates over the 6-year study period for W, B, H/E and H/S were 5.8%, 10.6%, 5.8%, and 4.4%, respectively. Rates of major decline in SROH were 14.6%, 23.2%, 22.1% and 39.4%, for W, B, H/E and H/S, respectively. Higher mortality rates for B versus W were mostly explained by worse baseline health. For major decline in SROH, education, income, and net worth independently explained more of the disparities for all three minority groups as compared to health behaviors and insurance, reducing the effect for B and H/E to non-significance, while leaving a significant elevated odds ratio for H/S. Without addressing the as-yet undetermined and pernicious effects of lower SES, public health initiatives that promote changing individual health behaviors and increasing rates of insurance coverage among blacks and Hispanics will not eliminate racial/ethnic health disparities.

Black or African American↗

Explaining delusions: a cognitive perspective.

There is now considerable evidence for reasoning, attention, metacognition and attribution biases in delusional patients. Recently, these findings have been incorporated into a number of cognitive models that aim to explain delusion formation, maintenance and content. Although delusions are commonly conceptualized as beliefs, not all models make reference to models of normal belief formation. This review considers those models that explain delusions as a breakdown of normal belief formation (belief-positive models), approaches that explain the pathology only (belief-negative models) and approaches that view delusions as one end of a distribution of anomalous mental phenomena (the continuum view). A cognitive theory that includes the 'pragmatic pathology' of delusions will be able to address both the phenomenology and the treatment of delusion-related distress.

Attention↗

Medical, psychosocial, and behavioral risk factors do not explain the increased risk for low birth weight among black women.

OBJECTIVE: Our purpose was to determine whether various demographic, behavioral, housing, psychosocial, or medical characteristics explain the difference in pregnancy outcome between black and white women. STUDY DESIGN: A sample of 1491 multiparous women with singleton pregnancies, 69% of whom were black and 31% of whom were white and who enrolled for care between Oct. 1, 1985, and March 30, 1988, participated in the study. The frequencies of various demographic, medical environmental, and psychosocial risk factors among black and white women were determined. The outcome measures were birth weight, gestational age, fetal growth restriction, preterm delivery and low birth weight. RESULTS: White infants were heavier and born later than black infants. The white women in this sample smoked more cigarettes, moved more frequently, and had worse psychosocial scores. The black women had lower incomes, were less likely to be married, and had more hypertension, anemia, and diabetes. Besides race, only maternal height, weight, blood pressure, diabetes, and smoking had a consistent impact on outcome and did not explain the difference in outcome between the two groups. CONCLUSION: In this low-income population, many of the risk factors for low birth weight were more common among white women than black women. Nevertheless, black women had more infants born preterm, with growth restriction, and with low birth weight than did white women. The various maternal characteristics studied did not explain these differences.

Black People↗

A model based upon pseudo regular spacing of cells combined with the randomisation of the nuclei can explain the significant changes in high-frequency ultrasound signals during apoptosis.

Recent ultrasound (US) experiments on packed myeloid leukaemia cells have shown that, at frequencies from 32 to 40 MHz, significant increases of signal amplitude were observed during apoptosis. This paper is an attempt to explain these signal increases based upon a simulation of the backscattered signals from the cells nuclei. The simulation is an expansion of work in which a condensed sample of cells, with fairly regular sizes, could be considered as an imperfect crystal. Thus, destructive interference could occur and this would be observed as a large reduced value of backscattered signals compared with the values obtained from a similar, but random, scattering source. This current paper explores the possibility that simple changes in the nuclei, such as their observed condensation or the small loss of nuclei scatterers from cells, could cause a significant increase in the observed backscattered signals. This model indicates that the greater backscattered signals can be explained by further randomisation of the average positions of the scattering sources in each cell. When these "microechoes" are added together, so that the destructive interference is reduced, a large increase in the signal is predicted. The simplified model strongly suggests that much of observed large increases of the backscattered signals could be simply explained by the randomisation of the position of the condensed nuclei during apoptosis, and the destruction of the nuclei could produce further signal amplitude changes due to disruption of the cloud of backscattered waves.

Apoptosis↗

Are therapeutic relationships in psychiatry explained by patients' symptoms? Factors influencing patient ratings.

OBJECTIVE: To investigate the therapeutic relationship and how it is influenced by sociodemographic and clinical factors. METHOD: This study analysed self-ratings of the therapeutic relationship in 90 first-admitted, 72 long-term hospitalised and 41 out-patients with schizophrenia along with 249 alcoholic and 42 depressive in-patients and their association with sociodemographic and clinical variables. In all the patients, the therapeutic relationship was assessed using a simple scale based on three items. RESULTS: The therapeutic relationship differed significantly across groups. It was rated most positively by alcoholic patients and least positively by long-term hospitalised schizophrenia patients. Increased observer-rated psychopathology was significantly associated with a poorer therapeutic relationship in all groups except the hospitalised schizophrenia patients. In this group, increased self-rated symptoms were associated with a poorer relationship. In multiple regression analyses, 3-28% of the relationship variance was explained by psychopathology. CONCLUSIONS; Patient ratings of the therapeutic relationship were partially explained by psychopathology, leaving the greater part of the variance to be explained by factors other than sociodemographic and clinical characteristics.

Adult↗

Using social cognitive theory to explain discretionary, "leisure-time" physical exercise among high school students.

PURPOSE: To examine whether knowledge of high school students' actions of self-regulation, and perceptions of self-efficacy to overcome exercise barriers, social situation, and outcome expectation will predict non-school related moderate and vigorous physical exercise. METHODS: High school students enrolled in introductory Physical Education courses completed questionnaires that targeted selected Social Cognitive Theory variables. They also self-reported their typical "leisure-time" exercise participation using a standardized questionnaire. Bivariate correlation statistic and hierarchical regression were conducted on reports of moderate and vigorous exercise frequency. RESULTS: Each predictor variable was significantly associated with measures of moderate and vigorous exercise frequency. All predictor variables were significant in the final regression model used to explain vigorous exercise. After controlling for the effects of gender, the psychosocial variables explained 29% of variance in vigorous exercise frequency. Three of four predictor variables were significant in the final regression equation used to explain moderate exercise. The final regression equation accounted for 11% of variance in moderate exercise frequency. CONCLUSIONS: Professionals who attempt to increase the prevalence of physical exercise through educational methods should focus on the psychosocial variables utilized in this study.

Adolescent↗

What features of the home and the area might help to explain observed relationships between housing tenure and health? Evidence from the west of Scotland.

This study aimed to explore the role of dwelling conditions and neighbourhood characteristics in explaining the frequently observed association between housing tenure and health. A postal questionnaire, focusing on a number of specific aspects of the home and the area, was sent to a random sample of adults in the west of Scotland (achieved sample size 2867, response rate 50%). The health measures were limiting long-standing illness, self-assessed health, recent symptoms, and anxiety and depression. Having controlled for age, sex, and marital status, housing tenure explained, respectively, 2.7%, 5.4%, 3.9%, 2.4% and 5.4% of the variance in these variables. These percentages were reduced by between 93% (for anxiety) and 73% (for self-assessed health) when housing problems, housing fixtures, overcrowding, dwelling type, access to garden, area type and area amenities were introduced into the model. This suggests that features of the dwelling and its surroundings help to explain observed associations between tenure and health in the UK, and that housing and area problems may be particularly important. Housing improvements and urban regeneration may help to reduce the health gap between housing tenures, and more generally to reduce inequalities in health.

Adult↗

Order in ectoparasite communities of marine fish is explained by epidemiological processes.

Two kinds of community structure referred to, nestedness and bimodal distribution, have been observed or were searched for in parasite communities. We investigate here the relation between these two kinds of organisation, using marine fishes as a model, in order to show that parasite population dynamics may parsimoniously explain the patterns of ectoparasite species distribution and abundance. Thirty six assemblages of metazoan ectoparasites on the gills and heads of marine fish showed the following patterns: a positive relationship between abundance and the variance of abundance; a positive relationship between abundance and prevalence of infection; a bimodal pattern of the frequency distribution of prevalence of infection; nestedness as indicated by Atmar and Patterson's thermodynamic measure (a mean of 7.9 degrees C); a unimodal distribution of prevalence in parasite assemblages with a temperature lower than the mean, and a bimodal distribution in assemblages with a temperature higher than the mean. We conclude that patterns are the result of characteristics of the parasite species themselves and that interspecific competition is not necessary to explain them. We emphasize that a holistic approach, taking all evidence jointly into account, is necessary to explain patterns of community structure. Ectoparasite assemblages of marine fish are among the animal groups that have been most thoroughly examined using many different methods, and all evidence supports the view that these animals live under non-equilibrium conditions, in largely non-saturated niche space in which interspecific competition occurs but is of little evolutionary importance.

Analysis of Variance↗

A new approach to explain concentration-dependent changes of isotropic Raman line width in the associated binary mixtures.

We report on a new empirical relationship to explain the concentration-dependent isotropic Raman line width changes of a vibrational mode in uniform binary mixtures. The factors contributing to the intrinsic line width and several other broadening mechanisms are, in general, concentration-dependent. Concentration fluctuation in a microscopic volume and microviscosity are the two factors that are known to cause a concentration-dependent line width variation. These two factors combined in a specific manner successfully explain the variation of the line width with concentration strongly associated with binary systems. A readily usable empirical relationship for line width is suggested. It has been demonstrated that it can successfully explain the line width variation with concentration in a given class of hydrogen-bonded systems taking some representative binary mixtures.

Journal Article↗