首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
To clarify the factors that determine the age when walking begins, this study first applied contingency tables and the chi 2 test to the questionnaire-data answered by the parents of 395 children. Among twelve factors, those that were not independent of the age of first walking were the use of a walker (p less than 0.01), the frequency of being carried on the chest (p less than 0.05) and the age of the first enrollment at a day-care center (less than 0.05). Second, this study employed the "quantification method of the second type" to clarify what factors help babies start walking early and what others do not. The subjects were divided into two groups--W0 (early-walkers) and W1 (others)--, and this grouping was used as an external criterion. The order of the factors according to the range of category scores is as follows: (1) birth weight, (2) order of birth, (3) frequency of being carried on the chest, (4) season of birth, (5) use of a walker, (6) age of the first enrollment at a day-care center. These factors included those that were not independent of the age of first walking ((3), (5), (6)). Therefore, the factors that had a wider range seem to be important in determining the age when babies start walking.  相似文献   

2.
香菇数量性状的因子分析   总被引:3,自引:1,他引:3  
因子分析结果表明,22个香菇菌株16个数量性状可分为弱相关的5个主因子,其方差积累贡献率为85.71%。按照主因子所包含的性状及其所反映的生物学含义,可把5个主因子命名并按方差贡献大小顺序排列为:F5,菇形因子;F1,菌柄因子;F3,营养生长因子;F2,生殖生长因子;F4,转色因子。从主因子出发进行香菇育种,可以加大目标性状的针对性和提高选择效率。  相似文献   

3.
《Plains anthropologist》2013,58(76):123-132
Abstract

This paper presents the result of an analysis of 24 burial mounds and cairns in southwest Missouri. All of the sites belong to the Fristoe Burial Complex with an estimated age of A. D. 500 to A.D. 1000. Data selected for analysis consisted of 41 traits distributed in varying numbers among the sites. In order to observe relationships between sites, a Q-type factor analysis was used. An orthogonal rotation yielded five factors. Three factors are discussed. Factors 2 and 5 are not discussed because of the small number of sites explained by them. Factor 1 loads heavily on eight sites and Factors 3 and 4 each on seven sites. Seventeen of the 24 sites are explained by the three factors which are hypothesized to represent three distinct temporal groupings. Factor 1 is thought to depict a late grouping based on trade relationships between the Gulf Coast and the Ozark Highlands. Factor 4 appears to be a grouping of Late Woodland elements, and Factor 3 possibly represents a set of Mississippian and Late Woodland elements. Results of the analysis allow us to hypothesize three temporal groupings within the Fristoe Burial Complex. The results further indicate that factor analysis can be used as a technique to order archeological materials and generate hypotheses.  相似文献   

4.
Z Chen  Y Zhang  Z Liu  Y Liu  A Dyregrov 《PloS one》2012,7(8):e41741

Aim

PTSD symptoms were pervasive among children and adolescents after experiencing or exposure to traumatic events. Screening and diagnosis of PTSD symptoms is crucial in trauma-related research and practice. The 13-item Children''s Revised Impact of Event Scale (CRIES) has been demonstrated to be a valid and reliable tool to achieve this goal. This study was designed to examine the psychometric properties of the 13-item CRIES in a sample of Chinese debris flood victims.

Methods

A total of 268 participants (145 girls, 123 boys) aged 8–18 years were recruited from an integral part of a service oriented project, supported by the Institute of Psychology, Chinese Academy of Sciences following the debris flood. The participants were given the 13-item CRIES 3 months after the debris flood.

Results

The results of confirmatory factor analysis indicated that a two-factor structure (intrusion+arousal vs avoidance) emerged as the model best fit in total sample, boys and girls subsamples, respectively. The scale was also demonstrated to have good internal consistency (Cronbach''s alpha = 0.83).

Conclusion

The study confirmed the good psychometric properties of the CRIES and its'' applicability to Chinese children and adolescents. Moreover, these findings imply that the CRIES factor structure is stable across age, gender, and different types of trauma.  相似文献   

5.
The purpose of the study was (a) to assess the accuracy of the regression equations available in the literature to estimate the actual peak power (PPac) of the countermovement jump (CMJ) executed by young male soccer players, (b) to develop new regression equations from this population, and (c) to verify whether regression equations obtained from age-based subgroups could increase the accuracy of the estimation (PPes) of PPac. In all, 117 young players (age: 13.6 ± 2.4 years) were enrolled in the study. Each subject performed 5 CMJs on a force platform. The new regression equations were obtained from the entire experimental sample (G1) and 3 age-based subsamples (G2 = prepubertal, G3 = peripubertal, G4 = postpubertal) using 2 different approaches: the best jump and the mean values achieved by each subject. All the equations in the literature underestimated the peak power (p < 0.00005) in all the groups. The approach based on the mean values was more accurate (adjusted R = 0.925, SEE = 302.9 W) than the one based on the best jump (adjusted R = 0.892; SEE = 360.8 W). Moreover, calculating the regression equations from the 3 age-based subsamples, SEE resulted improved (15.5% in G2, 5.6% in G3 and 0.9% in G4). Regression equations must be derived from homogeneous populations, in terms of gender, sports practice, and age. The approach based on the mean values for each subject was more accurate than the approach used in the literature up to now. In practical applications, regression equation estimates cannot be used to assess the performance of a single subject, because errors may exceed 50%, whereas they may be useful for group comparisons.  相似文献   

6.
Lengths within the cranial base and vault were measured in cephalometric radiographs of 220 boys and 177 girls ranging in age from 0 to 15 years; all these children are participants in The Fels Longitudinal Growth Study. The present study is based on mixed longitudinal data derived from 1640 radiographs for boys and 1260 radiographs for girls. Factor analysis was applied separately for boys and girls for each age group; i.e., 0–3, 4–6, 7–9, 10–12, and 13–15 years. For the 0–3 year age group, two factors were extracted in each sex, whereas four factors were extracted in the rest of the age groups. The factor structures are similar in the three older age groups of boys (7–9, 10–12, and 13–15 years). The first four factors for these groups are labelled, respectively: cranial vault size, posterior cranial base length, presphenoid length, and basisphenoid length. The order of the third and fourth factors is reversed in the 7–9 year olds. For girls, the factors extracted were also the same in both the 7–9 and 10–12 year age groups, even though the order of factors was different between age groups; i.e., anterior cranial base length, cranial vault size, basisphenoid length, and basioccipital length. Differential growth rates among cranial base dimensions probably cause changes in factor patterns. Obliteration of the spheno-occipital synchondrosis is suggested as the mechanism responsible for the change of factor pattern in the girls. Closure of this synchondrosis would have occurred too late to affect the patterns in boys.  相似文献   

7.
与光合微生物相比,非光合微生物固定CO2具有不用光照,可昼夜持续的优点.氮源是影响微生物固碳效率的重要因素.本研究围绕非光合固碳微生物培养中的氮源进行单因素实验,并在此基础上设计正交交互实验以确定最优的氮源组合.结果表明,实验中采用的三种无机氮对微生物固碳效率均有提升,其中( NH4)2SO4约在浓度为8g/L时达到最大值,NaNO3约在浓度为5 g/L时达到最大值而NaNO2约在浓度为5 g/L时达到最大值.根据单因素实验的结果设计L27(313)的正交交互实验表,得到不同氮源组合影响固碳效率的主次顺序:NaNO3和(NH4)2SO4是影响微生物固定CO2的主要因素,其余依次为NaNO3和(NH4)2SO4的交互作用,(NH4)2SO4和NaNO2的交互作用以及NaNO2等.同时三种氮源的最优组合为(NH4)2SO4浓度9 g/L,NaNO3浓度5 g/L和NaNO2浓度8 g/L,并得到三种因素影响的直观图.  相似文献   

8.

Background

An important attribute of the traditional impact factor was the controversial 2-year citation window. So far, several scholars have proposed using different citation time windows for evaluating journals. However, there is no confirmation whether a longer citation time window would be better. How did the journal evaluation effects of 3IF, 4IF, and 6IF comparing with 2IF and 5IF? In order to understand these questions, we made a comparative study of impact factors with different citation time windows with the peer-reviewed scores of ophthalmologic journals indexed by Science Citation Index Expanded (SCIE) database.

Methods

The peer-reviewed scores of 28 ophthalmologic journals were obtained through a self-designed survey questionnaire. Impact factors with different citation time windows (including 2IF, 3IF, 4IF, 5IF, and 6IF) of 28 ophthalmologic journals were computed and compared in accordance with each impact factor’s definition and formula, using the citation analysis function of the Web of Science (WoS) database. An analysis of the correlation between impact factors with different citation time windows and peer-reviewed scores was carried out.

Results

Although impact factor values with different citation time windows were different, there was a high level of correlation between them when it came to evaluating journals. In the current study, for ophthalmologic journals’ impact factors with different time windows in 2013, 3IF and 4IF seemed the ideal ranges for comparison, when assessed in relation to peer-reviewed scores. In addition, the 3-year and 4-year windows were quite consistent with the cited peak age of documents published by ophthalmologic journals.

Research Limitations

Our study is based on ophthalmology journals and we only analyze the impact factors with different citation time window in 2013, so it has yet to be ascertained whether other disciplines (especially those with a later cited peak) or other years would follow the same or similar patterns.

Originality/ Value

We designed the survey questionnaire ourselves, specifically to assess the real influence of journals. We used peer-reviewed scores to judge the journal evaluation effect of impact factors with different citation time windows. The main purpose of this study was to help researchers better understand the role of impact factors with different citation time windows in journal evaluation.  相似文献   

9.
This study addressed whether personality ratings using a 43 adjective questionnaire based on the Five-Factor Model generalized from a sample of 202 zoo-housed chimpanzees to a sample of 175 chimpanzees housed in Yerkes National Primate Research Center. Mean interrater reliabilities of adjectival ratings were lower for the chimpanzees housed in Yerkes. In addition, rank order of the interrater reliabilities of items differed between settings. To compare factor structure, we first examined whether we could replicate the original six factor structure found in an earlier study of 100 zoo chimpanzees using principal factors analysis in the Yerkes sample and 102 new zoo chimpanzees. The dominance, extraversion, conscientiousness, and agreeableness factors were clearly replicated in the Yerkes sample and the 102 new zoo chimpanzees. The Neuroticism and Openness factors did not replicate in the Yerkes sample, but they also did not replicate in the new zoo chimpanzees. These findings suggest the need to sample more adjectives representing neuroticism and openness in future versions of the questionnaire. We next sought to determine whether factor structure, as determined by principal components analysis, remained invariant across the two settings. This analysis revealed dominance, extraversion, conscientiousness, and agreeableness factors in both settings and a high level of congruence between the zoo and Yerkes samples for these factors. Finally, we tested whether factor scores in the two samples were similarly related to age and sex. With the exception of differences in age effects for dominance and agreeableness, age, and sex effects were consistent across samples. These findings suggest that, whereas there may be differences in the ease with which ratings are made, personality structure, and development are largely consistent across widely differing settings.  相似文献   

10.
The objective of this study is to identify prognostic factors of treatment response to atomoxetine in improvement of health-related quality of life (HR-QoL), measured by the Child Health and Illness Profile-Child Edition Parent Report Form (CHIP-CE PRF) Achievement and Risk Avoidance domains, in children and adolescents with attention-deficit/hyperactivity disorder (ADHD). Pooled data from 3 placebo-controlled trials and separate data from 3 open-label trials of atomoxetine in children and adolescents with ADHD were analyzed using logistic regression methods. Based on baseline impairment in the Achievement and/or Risk Avoidance domains (CHIP-CE PRF < 40 points), 2 subsamples of subjects were included. Treatment outcome was categorized as <5 points or ≥5 points increase in the CHIP-CE PRF Achievement and Risk Avoidance domains. Data of 190 and 183 subjects from the pooled sample, and 422 and 355 subjects from the open-label trials were included in the analysis of Achievement and Risk Avoidance domains. Baseline CHIP-CE subdomain scores proved to be the most robust prognostic factors for treatment outcome in both domains, based on data from the pooled sample of double-blind studies and from the individual open-label studies (odds ratios [OR] 0.74–1.56, p < 0.05; OR < 1, indicating a worse baseline score associated with worse odds of responding). Initial treatment response (≥25 % reduction in ADHD Rating Scale scores in the first 4–6 weeks) was another robust prognostic factor, based on data from the open-label studies (OR 2.99–6.19, p < 0.05). Baseline impairment in HR-QoL and initial treatment response can be early prognostic factors of atomoxetine treatment outcome in HR-QoL in children and adolescents with ADHD.  相似文献   

11.
12.

Background

Some syphilis patients remain in a serologically active state after the recommended therapy. We currently know too little about the characteristics of this serological response.

Methods

We conducted a cohort study using the clinical database from Zhongshan Hospital, Medical College of Xiamen. In total, 1,327 HIV-negative patients with primary, secondary, latent, and tertiary syphilis were enrolled. Bivariate and multivariate analyses were utilised to identify factors associated with a serological cure and serofast state in syphilis patients one year after therapy. Chi-square tests were used to determine the differences in the serological cure rate across different therapy time points.

Results

One year after the recommended therapy, 870 patients achieved a serological cure, and 457 patients (34.4%) remained in the serofast state. The serological cure rate increased only within the first 6 months. The bivariate analysis indicated that male or younger patients had a higher likelihood of a serological cure than female or older patients. Having a baseline titre ≤1∶2 or ≥1∶64 was associated with an increased likelihood of a serological cure. The serological cure rate decreased for the different disease stages in the order of primary, secondary, latent, and tertiary syphilis. A distinction should be drawn between early and late syphilis. The multivariate analysis indicated that a serological cure was significantly associated with the disease phase, gender, age, and baseline rapid plasma reagin (RPR) titre.

Conclusions

The serofast state is common in clinical work. After one year of the recommended therapy, quite a few syphilis patients remained RPR positive. The primary endpoint of the study indicated that disease phase, gender, age and baseline RPR titre were crucial factors associated with a serological cure.  相似文献   

13.

Objectives

The primary objective of this study was to identify the existence of chronic disease multimorbidity patterns in the primary care population, describing their clinical components and analysing how these patterns change and evolve over time both in women and men. The secondary objective of this study was to generate evidence regarding the pathophysiological processes underlying multimorbidity and to understand the interactions and synergies among the various diseases.

Methods

This observational, retrospective, multicentre study utilised information from the electronic medical records of 19 primary care centres from 2008. To identify multimorbidity patterns, an exploratory factor analysis was carried out based on the tetra-choric correlations between the diagnostic information of 275,682 patients who were over 14 years of age. The analysis was stratified by age group and sex.

Results

Multimorbidity was found in all age groups, and its prevalence ranged from 13% in the 15 to 44 year age group to 67% in those 65 years of age or older. Goodness-of-fit indicators revealed sample values between 0.50 and 0.71. We identified five patterns of multimorbidity: cardio-metabolic, psychiatric-substance abuse, mechanical-obesity-thyroidal, psychogeriatric and depressive. Some of these patterns were found to evolve with age, and there were differences between men and women.

Conclusions

Non-random associations between chronic diseases result in clinically consistent multimorbidity patterns affecting a significant proportion of the population. Underlying pathophysiological phenomena were observed upon which action can be taken both from a clinical, individual-level perspective and from a public health or population-level perspective.  相似文献   

14.
Age estimation of unknown skeletal remains is very important in forensic medicine. Morphologic methods are fast and easy to use for purpose of age determination. The sternal ends of the ribs are a reliable method of age estimation from late adolescence to old age. Iscan et al developed a phase analysis method for the right 4th rib that was sex and race specific. The purpose of this study is to determine the accuracy of the standards of age estimation from the right 4th and other rib using the phase analysis for the Turkish population. The sample consisted of right and left 3rd, 4th and 5th ribs from 34 Turkish women and 76 men. There were statistically significant variations found on the right 5th, left 3rd, 4th, and 5th ribs according to these standards in men for phases 5, 6, and 7. For women, all the right and left ribs included in this study were in concordance with right 4th rib standards in all phases.  相似文献   

15.
Body segment parameters (BSPs) such as segment mass, center of mass, and radius of gyration are required in many ergonomic tools and biomechanical models to estimate injury risk, and quantify muscle and joint contact forces. Currently, the full effects of age and obesity have not been taken into account when predicting BSPs. The goal of this study is to quantify the impact of body mass index (BMI) and age on BSPs, in order to provide more representative measures necessary for modeling inputs. A whole body dual energy X-ray absorptiometry (DXA) scan was collected for 280 working men and women with a wide range of BMI and aged 21 to 70 years. Established DXA processing methods were used to determine in-vivo estimates of the mass, center of mass, and radius of gyration for the upper arm, forearm, torso, thigh, and shank for males and females. Regression models were used to determine if age and BMI terms, as well as their interactions, were associated with these BSPs. The variability in BSPs explained by BMI alone ranged from 4 to 51%, and age explained an additional 3–19%. Thus, BMI and age are significant correlates of BSPs, and need to be taken into account when predicting certain BSPs in order to obtain accurate and representative results in biomechanical models.  相似文献   

16.
AIMS: To determine the factors which influence the suppression of thyroid-stimulating hormone (TSH) in infants with congenital hypothyroidism (CH) following treatment. METHODS: We examined retrospectively the patterns of thyroid function tests from diagnosis to 3 years of age in 140 infants diagnosed with CH from screening. Patients were classified into 3 groups: athyreosis, ectopia and presumed dyshormonogenesis on the basis of thyroid scans. Adequate TSH suppression was defined as plasma TSH concentration <6 mU/l. The factors affecting the suppression of TSH at 6 months and 1 year of age which were evaluated were: initial confirmatory plasma TSH, initial plasma thyroxine (T4), mean age of starting treatment with L-T4, dose of L-T4 at diagnosis, 6 weeks, 3 months and 6 months, and aetiology of the congenital hypothyroidism. Variables were then entered in a stepwise logistic regression model for TSH suppression at 6 months and 1 year of age. RESULTS: All infants had radionuclide scans prior to treatment: athyreosis (n = 39), ectopia (n = 78) and dyshormonogenesis (n = 23). 58% of patients had persistently raised TSH at 6 months of age while 31% of patients had a persistently raised TSH at 1 year of age. There was a significant delay in the normalisation of plasma TSH in athyreosis and ectopia groups compared with dyshormonogenesis. Multiple regression analysis for TSH suppression at 6 months of age found plasma T4 levels and aetiology of CH as independent factors affecting the timing of TSH suppression. Aetiology of CH was the only independent factor affecting TSH suppression at 1 year of age. CONCLUSION: At 6 months of age, plasma T4 levels at 6 weeks and 3 months, and aetiology of CH were independent factors affecting timing of TSH suppression. However, by 1 year of age, the aetiology of CH was the only independent factor affecting suppression of TSH.  相似文献   

17.

AIM:

The study was aimed to determine the association of Apolipoprotein E (apo E) gene polymorphisms on lipid levels in Asian Indian population.

METHODS:

A total of 350 (184 males and 166 females) adult (30 years and above) Asian Indians of Calcutta and suburb participated in the study. Anthropometric measures, lipids profiles, and blood glucose measures were collected. Out of 350 subjects, a sample of 70 individuals was selected randomly for genotyping after adjusting for age and sex. The apo E gene polymorphisms were determined by agarose gel electrophoresis.

RESULTS:

The apo E polymorphism showed significant association with dyslipidaemia (P=0.0135) with ε3/4 combination has had the highest occurrence of dyslipidaemia and metabolic syndrome (MS) followed by ε4/4 <ε3/3 <ε2/4 <ε2/3 in decreasing order.

CONCLUSIONS:

The ε4 allele of apo E gene independent of other risk factors is associated with dyslipidaemia in particular with low HDLc and high TC: HDLc ratio.  相似文献   

18.

Background and aims

Soils derived from serpentinite (serpentine soils) often have low macronutrient concentrations, exceedingly low Ca:Mg molar ratios and high heavy metal concentrations, typically resulting in sparse vegetative cover. This combined suite of edaphic stresses is referred to as the “serpentine syndrome.” Although several plant community-level studies have been conducted to identify the most important edaphic factor limiting plant growth on serpentine, the primary factor identified has often varied by plant community and local climate. Few studies to date have been conducted in serpentine plant communities of alpine or boreal climates. The goal of our study was to determine the primary limiting edaphic factors on plant community species composition and productivity (cover) in the alpine and boreal climate of the Western Alps, Italy.

Methods

Soil properties and vegetation composition were analyzed for several sites underlain by serpentinite, gabbro, and calc-schist substrates and correlated using direct and indirect statistical methods.

Results

Boreal forest soils were well-developed and tended to have low pH throughout the soil profile resulting in high Ni availability. Alpine soils, in comparison, were less developed. The distinct serpentine plant communities of the Western Alps are most strongly correlated with high levels of bioavailable Ni associated with low soil pH. Other factors such as macronutrient deficiency, low Ca:Mg molar ratio and drought appear to be less important.

Conclusions

The strong ecological influence of Ni is caused by environmental conditions which increase metal mobilization.  相似文献   

19.

Background

Osteoprotegerin is a member of the tumor necrosis factor-related family and inhibits RANK stimulation of osteoclast formation as a soluble decoy receptor. The goal of this study was to determine the relationship of serum osteoprotegerin with vascular calcification in patients with type 2 diabetes.

Methods

The subjects were 124 patients with type 2 diabetes mellitus, including 88 males and 36 females with a mean (± SD) age of 65.6 ± 8.2 years old. Serum levels of osteoprotegerin, osteocalcin, fibroblast growth factor 23 (FGF23), 25-hydroxyvitamin D3 and adiponectin were measured by ELISA. Vascular calcification in the cervical artery was examined by ultrasound sonography. The subjects were divided into 4 quartiles depending on serum osteoprotegerin levels.

Results

Vascular calcification was significantly higher in the 4th quartile and significantly lower in the 1st quartile of serum osteoprotegerin levels, compared to other quartiles. There were no differences in serum osteoprotegerin and vascular calcification among patients with different stages of diabetic nephropathy, but serum FGF23 levels were elevated in those with stage 4 diabetic nephropathy. Simple regression analysis showed that serum osteoprotegerin levels had significant positive correlations with age, systolic blood pressure and serum adiponectin levels, and significant negative correlations with BMI and serum 25-hydroxyvitamin D3.

Conclusions

These findings suggest that elevated serum osteoprotegerin may be involved in vascular calcification independently of progression of diabetic nephropathy in patients with type 2 diabetes.  相似文献   

20.
植被NPP作为衡量陆地生态系统的关键指标和地表碳循环的重要组成部分,能够合理地评价生态系统变化及其可持续性。基于MOD17A3数据,借助GIS空间分析、相关性分析及地理探测器模型等方法,探讨了2000—2014年秦巴山区NPP时空格局及演变特征,并对影响NPP的自然和人为因子进行量化研究。结果表明:(1)秦巴山区近15年NPP总量整体呈波动增加趋势,增速0.65TgC a~(-1),单位面积NPP均值为493.09gC m~(-2) a~(-1),呈"西高东低"空间特征,地域差异明显;(2)不同植被类型的NPP总量存在差异,阔叶林和栽培植被是对秦巴山区生态系统最具贡献的植被类型;(3)NPP随高程、坡度均呈阶段性变化特征,其中坡度影响NPP变化的幅度弱于高程,NPP与降雨、气温、实际蒸散量均呈显著正相关关系;(4)自然因子对NPP贡献率存在显著差异(P0.01),依次排序为:实际蒸散量降雨气温高程坡度,且研究区NPP受多种自然因子的交互影响;(5)人为因子对NPP的影响表现为土地利用类型变化造成NPP总量的损益,可分为还林还草的积极效应及城市发展和人类破坏等的消极效应。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号