965 resultados para Nonlattice self-similar fractal strings
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A major goal of experimental and clinical hematology is the identification of mechanisms and conditions that support the expansion of transplantable hematopoietic stem cells. In normal marrow, such cells appear to be identical to (or represent a subset of) a population referred to as long-term-culture-initiating cells (LTC-ICs) so-named because of their ability to produce colony-forming cell (CFC) progeny for > or = 5 weeks when cocultured with stromal fibroblasts. Some expansion of LTC-ICs in vitro has recently been described, but identification of the factors required and whether LTC-IC self-renewal divisions are involved have remained unresolved issues. To address these issues, we examined the maintenance and/or generation of LTC-ICs from single CD34+ CD38- cells cultured for variable periods under different culture conditions. Analysis of the progeny obtained from cultures containing a feeder layer of murine fibroblasts engineered to produce steel factor, interleukin (IL)-3, and granulocyte colony-stimulating factor showed that approximately 20% of the input LTC-ICs (representing approximately 2% of the original CD34+ CD38- cells) executed self-renewal divisions within a 6-week period. Incubation of the same CD34+ CD38- starting populations as single cells in a defined (serum free) liquid medium supplemented with Flt-3 ligand, steel factor, IL-3, IL-6, granulocyte colony-stimulating factor, and nerve growth factor resulted in the proliferation of initial cells to produce clones of from 4 to 1000 cells within 10 days, approximately 40% of which included > or = 1 LTC-IC. In contrast, in similar cultures containing methylcellulose, input LTC-ICs appeared to persist but not divide. Overall the LTC-IC expansion in the liquid cultures was 30-fold in the first 10 days and 50-fold by the end of another 1-3 weeks. Documentation of human LTC-IC self-renewal in vitro and identification of defined conditions that permit their extensive and rapid amplification should facilitate analysis of the molecular mechanisms underlying these processes and their exploitation for a variety of therapeutic applications.
Similar antigenic surfaces, rather than sequence homology, dictate T-cell epitope molecular mimicry.
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Molecular mimicry, normally defined by the level of primary-sequence similarities between self and foreign antigens, has been considered a key element in the pathogenesis of autoimmunity. Here we describe an example of molecular mimicry between two overlapping peptides within a single self-antigen, both of which are recognized by the same human self-reactive T-cell clone. Two intervening peptides did not stimulate the T-cell clone, even though they share nine amino acids with the stimulatory peptides. Molecular modeling of major histocompatibility complex class II-peptide complexes suggests that both of the recognized peptides generate similar antigenic surfaces, although these are composed of different sets of amino acids. The molecular modeling of a peptide shifted one residue from the stimulatory peptide, which was recognized in the context of the same HLA molecule by another T-cell clone, generated a completely different antigenic surface. Functional studies using truncated peptides confirmed that the anchor residues of the two "mimicking" epitopes in the HLA groove differ. Our results show, for two natural epitopes, how molecular mimicry can occur and suggest that studies of potential antigenic surfaces, rather than sequence similarity, are necessary for analyzing suspected peptide mimicry.
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Neurospora VS RNA performs an RNA-mediated self-cleavage reaction whose products contain 2',3'-cyclic phosphate and 5'-hydroxyl termini. This reaction is similar to those of hammerhead, hairpin, and hepatitis delta virus ribozymes; however, VS RNA is not similar in sequence to these other self-cleaving motifs. Here we propose a model for the secondary structure of the self-cleaving region of VS RNA, supported by site-directed mutagenesis and chemical modification structure probing data. The secondary structure of VS RNA is distinct from those of the other naturally occurring RNA self-cleaving domains. In addition to a unique secondary structure, several Mg-dependent interactions occur during the folding of VS RNA into its active tertiary conformation.
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The aim of this paper is to provide evidence that overweight individuals are at increased risk for emotional abuse compared to their normal weight counterparts. Studies examining weight-based discrimination and bullying demonstrate examples of emotional abuse aimed at overweight individuals. The psychological difficulties associated with emotional abuse, such as symptoms of anxiety, depression and social difficulties, are reviewed. It is hypothesized that similar psychological difficulties are experienced when obese persons experience weight based emotional abuse. A self psychological conceptualization is applied to understand the effect emotional abuse has on one's sense of self. A treatment proposal, which aims to utilize self-object transferences to strengthen the self, is offered. Future research for the application of self psychology in a group therapy format is discussed.
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Specific training for conducting psychotherapy with gay men is limited for psychologists, particularly when using a Self Psychology theoretical orientation (Robertson, 1996). In fact, psychologists often are faced with conflicting and contradictory points of view that mirror society's condemnation of homosexuality (Robertson, 1996). This paper is written from a self-psychological perspective to address the lack of a constructive body of literature that explains the unique treatment needs which impact gay men. Estimates of the prevalence of male homosexuality have generated considerable debate. A common assumption is that there are homosexual and non-homosexual men. However, scientists have long been aware that sexual responsiveness to others of the same sex, like most human traits, is continuously distributed in the population (Michaels, 1996). Still the presumption exists that such traits are stable within each man over time (Michaels, 1996). Conflating same-sex sexual experiences with a categorization of the man as homosexual is problematic, in that defining sexuality solely on the basis of experience excludes people who fantasize about sex with others of the same sex but never have sexual contact. Thus, most modern conceptions of sexual orientation consider personal identification, sexual behavior, and sexual fantasy (McWhirter, Sanders & Reinisch, 1990). Gay men's mental health can only be understood in the context of homosexuality throughout history, since religious and moral objections to sexual attraction between men have existed for centuries. Men who desired other men were regarded as sinful and depraved if not ill or abnormal, and same sex contacts were not distinguished from lewd behaviors (Weeks, 1989). Although most people, regardless of sexual orientation, have experienced some feelings of personal rejection, rarely do heterosexuals become targets for disapproval based on the nature of their attractions and behaviors relative to the same and to the other sex. For lesbians, bisexuals, and gay men, however, homosexuality becomes the focus of aspects of themselves that make them feel hated and hateful (Isay, 1989). While gay men and lesbians are often considered together because of the same-sex nature of their relationships and the similar issues that they may experience in their treatment within society, there are many issues where they might be best studied separately. Issues involving with health, parenthood, sexuality and perceived roles and status in society, for example, are often related more to gender than to any shared concept of a 'gay and lesbian community'. Many issues surrounding lesbians and lesbian culture will have more to do with women's issues, and some issues involving with gay men will have more to do with the gay male subculture and with masculinity. The author of this paper has limited experience in working with lesbian and bisexual individuals, and although it is likely that some of the concepts articulated in this paper could translate to working with lesbian and bisexual individuals, further research is indicated to examine the beneficence of utilizing a Self Psychological orientation in psychotherapy with lesbian women and bisexual individuals. This paper presents an overview of the literature including historical treatments of homosexuality, the history of Self Psychology, key principles in Self Psychology, research on Self Psychology, identity development models for gay men, and Self Psychological perspectives on identity development related to gay men. The literature review is followed by a section on treatment implications for psychologists seeking to treat gay men, including case vignettes based on work from my own practice. I have preserved the anonymity of clients by changing demographics, and rearranging and combining presenting issues and historical backgrounds among the case examples.
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Self-regulation has been identified as an area of difficulty for those with mental retardation. The Goodman Lock Box provides measures of two critical aspects of self-regulation-planfulness and maintenance of goal-directed behavior. In this study, the Lock Box performance of 25 children with Down syndrome was compared with that of 43 typically developing children, matched for mental age (24-36 months). Children in both groups showed similar levels of competence, planfulness and distractibility. However, children with Down syndrome displayed more task-avoidant behavior. Some issues related to the measurements obtained from the Lock Box are raised. (C) 2003 Elsevier Science Ltd. All rights reserved.
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There is no specific self-efficacy measure that has been developed primarily for problem drinkers seeking a moderation drinking goal. In this article, we report the factor structure of a 20-item Controlled Drinking Self-Efficacy Scale (CDSES Sitharthan et al., 1996; Sitharthan et al., 1997). The results indicate that the CDSES is highly reliable, and the factor analysis using the full sample identified four factors: negative affect, positive mood/social context, frequency of drinking, and consumption quantity. A similar factor structure was obtained for the subsample of men. In contrast, only three factors emerged in the analysis of data on female participants. Compared to women, men had low self-efficacy to control their drinking in situations relating to positive mood/social context, and subjects with high alcohol dependence had low self-efficacy for situations relating to negative affect, social situations, and drinking less frequently. The CDSES can be a useful measure in treatment programs providing a moderation drinking goal. (C) 2003 Wiley Periodicals, Inc.
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Shihāb al-Dīn Suhrawardī (d.687/1191) proposed a theory of apperception that constitutes the core of his “illuminative” epistemology. His theory of apperception purports to account for the soul’s immediate, reflexive, and unmediated knowledge of its own essence. Apperception may be defined as the direct experience the soul has of its essence. A closer examination of the Avicennan tradition (Avicenna died in 420/1037) reveals the existence of a number of arguments for the demonstration of an apperception of the self/soul similar to the arguments Suhrawardī later proposes. Contrary to admitted views, Avicenna had tackled issues related to the soul’s apperception, a type of perception distinct from the soul’s intellection of its essence. Avicenna alluded to the existence of a mode of perception specific to the soul that would guarantee both the soul’s unity and its personal identity. This apperception is defined as an unmediated presence of the soul to itself. These elements recur in Suhrawardī’s theory of apperception and numerous versions of Avicenna’s arguments for the demonstration of the presential nature of apperception
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The aim in the current study was to investigate the emergence of pretend play, mirror self-recognition, synchronic imitation and deferred imitation in normally developing human infants. A longitudinal study was conducted with 98 infants seen at three-monthly intervals from 12 through to 24 months of age. At each session the infants were tested on a range of tasks assessing the four target skills. Deferred imitation was found to emerge prior to synchronic imitation, pretend play and mirror self-recognition. In contrast, the latter three skills emerged between 18 and 21 months and followed similar developmental trajectories. Deferred imitation was found to hold a prerequisite relation with these three skills. Synchronic imitation, pretend play and mirror self-recognition were not closely associated and no prerequisite relations were found between these skills. These findings are discussed in the context of current theories regarding the development of pretend play, mirror self-recognition, synchronic imitation and deferred imitation in the second year. (C) 2004 Elsevier Inc. All rights reserved.
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Samples from New Zealand and Australia have been tested in an adiabatic oven to assess the effect of rank on the R-70 selfheating rate of coal. A non-linear relationship can be defined for coals from both countries using the revised Suggate rank (S-r) parameter. Subbituminous coals have the highest R-70 self-heating rate values, which are 20 times that of high volatile A bituminous coals on a dry mineral matter free basis (similar to 1 cf. 20 degrees C h(-1)). However, the moderating effects of moisture and mineral matter can reduce this difference to only 2-3 times for coal in-situ. (c) 2005 Elsevier B.V All rights reserved.
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Objectives: To estimate differences in self-rated health by mode of administration and to assess the value of multiple imputation to make self-rated health comparable for telephone and mail. Methods: In 1996, Survey 1 of the Australian Longitudinal Study on Women's Health was answered by mail. In 1998, 706 and 11,595 mid-age women answered Survey 2 by telephone and mail respectively. Self-rated health was measured by the physical and mental health scores of the SF-36. Mean change in SF-36 scores between Surveys 1 and 2 were compared for telephone and mail respondents to Survey 2, before and after adjustment for socio-demographic and health characteristics. Missing values and SF-36 scores for telephone respondents at Survey 2 were imputed from SF-36 mail responses and telephone and mail responses to socio-demographic and health questions. Results: At Survey 2, self-rated health improved for telephone respondents but not mail respondents. After adjustment, mean changes in physical health and mental health scores remained higher (0.4 and 1.6 respectively) for telephone respondents compared with mail respondents (-1.2 and 0.1 respectively). Multiple imputation yielded adjusted changes in SF-36 scores that were similar for telephone and mail respondents. Conclusions and Implications: The effect of mode of administration on the change in mental health is important given that a difference of two points in SF-36 scores is accepted as clinically meaningful. Health evaluators should be aware of and adjust for the effects of mode of administration on self-rated health. Multiple imputation is one method that may be used to adjust SF-36 scores for mode of administration bias.
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Individuals seeking compensation following traumatic brain injury (TBI) are often found to report a disproportionately high level of symptoms relative to objective indicators of impairment. Previous studies highlight that level of symptom reporting is also related to self-awareness, causal attribution, and emotional wellbeing. Therefore, the reasons for high symptom reporting in the context of compensation are generally unclear. This study aimed to identify whether self-awareness, causal attribution, and emotional wellbeing are significantly associated with level of symptom reporting after controlling for compensation status. A sample of 54 participants with TBI comprised two groups, namely, claimants (n = 27) and non-claimants (n = 27), who were similar in terms of demographic and neuro-cognitive variables. Participants completed the Symptom Expectancy Checklist, Hospital Anxiety Depression Scale, Awareness Questionnaire and a causal attribution scale. A series of independent t tests and Pearson's correlations identified that a higher level of symptom reporting was associated with the following: seeking compensation, less severe TBI, increased age, greater self-awareness, increased post-injury changes reported by relatives, a higher level of mood symptoms, and a tendency to blame other people. Multivariate analysis identified that after controlling for demographic, injury, and compensation status variables, level of mood symptoms and self-awareness were significantly associated with level of symptom reporting. The findings suggest that mood symptoms and heightened self-awareness are significantly related to high symptom reporting independent of compensation status, thus supporting the need for clinicians to interpret symptom reporting within a biopsychosocial context.
Bias, precision and heritability of self-reported and clinically measured height in Australian twins
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Many studies of quantitative and disease traits in human genetics rely upon self-reported measures. Such measures are based on questionnaires or interviews and are often cheaper and more readily available than alternatives. However, the precision and potential bias cannot usually be assessed. Here we report a detailed quantitative genetic analysis of stature. We characterise the degree of measurement error by utilising a large sample of Australian twin pairs (857 MZ, 815 DZ) with both clinical and self-reported measures of height. Self-report height measurements are shown to be more variable than clinical measures. This has led to lowered estimates of heritability in many previous studies of stature. In our twin sample the heritability estimate for clinical height exceeded 90%. Repeated measures analysis shows that 2-3 times as many self-report measures are required to recover heritability estimates similar to those obtained from clinical measures. Bivariate genetic repeated measures analysis of self-report and clinical height measures showed an additive genetic correlation > 0.98. We show that the accuracy of self-report height is upwardly biased in older individuals and in individuals of short stature. By comparing clinical and self-report measures we also showed that there was a genetic component to females systematically reporting their height incorrectly; this phenomenon appeared to not be present in males. The results from the measurement error analysis were subsequently used to assess the effects of error on the power to detect linkage in a genome scan. Moderate reduction in error (through the use of accurate clinical or multiple self-report measures) increased the effective sample size by 22%; elimination of measurement error led to increases in effective sample size of 41%.
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Whereas projection of self-attributes to ingroups is ubiquitous, projection of self-attributes to outgroups (outgroup projection) is an elusive phenomenon. Two experiments examined the moderating effect of perceived intergroup relationship on outgroup projection and explored underlying mechanisms. Perceived cooperation versus competition between ingroup and outgroup was manipulated using fictitious (Experiment 1) or natural groups (Experiment 2). In both experiments, participants judged the outgroup as more similar to the self in the cooperation condition than in the competition condition. This effect was independent of recategorization, perceived intergroup similarity, and ingroup-to-outgroup projection. These studies demonstrate the very existence of outgroup projection and extend previous work on moderators of projection from self to groups.
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Background: Coronary heart disease patients have to learn to manage their condition to maximise quality of life and prevent recurrence or deterioration. They may develop their own informal methods of self-management in addition to the advice they receive as part of formal cardiac rehabilitation programmes. This study aimed to explore the use of complementary and alternative medicines and therapies (CAM), self-test kits and attitudes towards health of UK patients one year after referral to cardiac rehabilitation. Method: Questionnaire given to 463 patients attending an assessment clinic for 12 month follow up in four West Midlands hospitals. Results: 91.1% completed a questionnaire. 29.1% of patients used CAM and/or self-test kits for self-management but few (8.9%) used both methods. CAM was more often used for treating other illnesses than for CHD management. Self-test kit use (77.2%,) was more common than CAM (31.7%,) with BP monitors being the most prevalent (80.0%). Patients obtained self-test kits from a wide range of sources, for the most part (89.5%) purchased entirely on their own initiative. Predictors of self-management were post revascularisation status and higher scores on 'holism', 'rejection of authority' and 'individual responsibility'. Predictors of self-test kit use were higher `holism' and 'individual responsibility' scores. Conclusion: Patients are independently using new technologies to monitor their cardiovascular health, a role formerly carried out only by healthcare practitioners. Post-rehabilitation patients reported using CAM for self-management less frequently than they reported using self-test kits. Reports of CAM use were less frequent than in previous surveys of similar patient groups. Automatic assumptions cannot be made by clinicians about which CHD patients are most likely to self-manage. In order to increase trust and compliance it is important for doctors to encourage all CHD patients to disclose their self-management practices and to continue to address this in follow up consultations.