An experimental and theoretical model of children’s search behavior in relation to target conspicuity and spatial distribution

This work explores search trajectories of children attempting to find targets distributed on a playing field. This task, of ludic nature, was developed to test the effect of conspicuity and spatial distribution of targets on the searcher’s performance. The searcher’s path was recorded by a Global Positioning System (GPS) device attached to the child’s waist. Participants were not rewarded nor their performance rated. Variation in the conspicuity of the targets influenced search performance as expected; cryptic targets resulted in slower searches and longer, more tortuous paths. Extracting the main features of the paths showed that the children: (1) paid little attention to the spatial distribution and at least in the conspicuous condition approximately followed a nearest neighbor pattern of target collection, (2) were strongly influenced by the conspicuity of the targets. We implemented a simple statistical model for the search rules mimicking the children’s behavior at the level of individual (coarsened) steps. The model reproduced the main features of the children’s paths without the participation of memory or planning.     

家国叙事与个体精神叙事的叠合与断裂—从《财主底儿女们》为出发点看中国小说的叙述特质

路翎的《财主底儿女们》自问世后争议不断,一个重要原因在于它呈现的是一种丁字形的结构。具体体现在：其第一部与传统的家国叙事传统叠合,第二部则聚焦个体精神叙事。当后者包蕴的精神性叙事渐渐壮大、膨胀,并自成天地后,与专注于世俗世界的叙事模式便不可避免地发生冲突。原有的以家国命运盛衰荣枯为主轴的叙述框架已无法容纳如此丰富繁杂的主观内容。貌似整全统一的叙述结构产生了断裂,而《财主底儿女们》全书显现的第一部与第二部间的丁字形结构正是这一冲突外显的症候。这两种叙述方式间的断裂,不仅仅是外在叙述形式上的歧异所致,更是不同的文化选择和精神价值取向间的摩擦和冲突。     

基于X射线荧光光谱仪的儿童沙坑重金属污染特征调查研究

儿童沙坑是学龄前儿童重要的户外游乐场所,同时具有较好的雨水下渗性能,导致伴随周边地表径流而来的污染物容易在其中富集。因此儿童在沙坑内玩耍时,面临重金属类污染物进入体内的健康风险。研究利用X射线荧光光谱法(XRF)快速、无损的检测特点,对北京市儿童沙坑重金属污染特征进行调查。结果表明：(1)XRF对自制标准试样中Pb, Cu, As和Cd的测量值与理论值的准确度为-1.3%～7.5%,精确度在1.1%～5.3%范围内,均符合相关环境质量检测技术规范中规定的仪器检测准确度和精密度要求(均小于10%);(2)4种重金属测量值与理论值之间均呈现极显著正相关关系(p<0.001),其决定系数(R²)分别为0.999, 0.999, 0.996和0.998,基于结果建立了测量值和理论值的拟合方程;(3)应用XRF对北京市17家公园和13个居民小区内儿童沙坑重金属含量进行测定,两组样点中Pb和As含量差异显著,而Cu和Cd含量无显著差异。4种重金属标准差的变异系数范围在0.24～0.43,其中除Cd的变异系数小于0.3外,其余重金属均大于0.3,表明空间变异明显;(4)与...     

The [15N]Methacetin Liver Function Test Characterizes Multicomponent Exposure of Children in Industrially Polluted Regions

Abstract

The [¹⁵N]methacetin urine test for assessing disturbances of the cytochrome P₄₅₀-aided oxygenation of xenobiotics in the human liver has been approved in several environmental health studies. A recent longitudinal study of kindergarten children near chemical and mining companies undergoing fundamental restructuring showed high, seasonally fluctuating SO₂ burden which was well correlated with alterations in the mean liver states of the children. At one point the correlation disappeared, together with indications of large amounts of chlorinated compounds overflowing locally at nighttime. This was finally proven by analyzing urine samples from the children for trichloroacetic acid (TCA). Chlorinated ethanes and ethenes—the precursors of TCA—seemed to dominate the air pollution and to affect the hepatic detoxification capacity. We concluded that the methacetin liver function test reflects multicomponent exposure, including acute monopolization by a dominant pollutant for a time.     

Vocalization and breathing during the second and third years of life

Vocalization and breathing were studied in 40 healthy young children,including 5 boys and 5 girls at each, of ages of 18, 24, 30, and 36 months. A variable inductance plethysmograph was used to obtain estimates of volume changes of the rib cage, abdomen, and lung, as well as estimates of selected temporal features of the breathing cycle. Results indicated that breathing behavior was influenced by height and age, but not by vocalization type or sex. Such behavior was found to be highly variable, demonstrating that these young children had multiple degrees of freedom of performance available to accomplish the aeromechanical drive required.     

小儿肾病综合征患儿血中锌,铜,铁,钙,铅的研究

为探讨小儿肾病综合征患儿血中锌,铜,铁钙,铅的变化规律,对６０例小儿肾病综合征和６０例正常儿童全血中锌,铜,铁、钙,铅含量进行了对比观察。结果表明,小儿肾病综合征患儿以上５种元素均比正常儿童降低,     

Attitudes of Children With Dysphonia

SUMMARY: Because voice disorders in childhood may have a negative impact on communicative effectiveness, social development, and self-esteem, the objective was to determine the impact of voice disorders on lives of children from the perspective of chronically dysphonic children and their parents. This study consisted of focused interviews with chronically dysphonic children and their caregivers. Focused interviews were conducted with 10 children in each of the following age groups: Toddler (2-4 years old), Young Child (5-7 years old), School-Aged Child (8-12 years old), and Adolescent (13-18 years old). Interview questions were formulated to elicit attitudes in the following conceptual domains: emotional, social/functional, and physical. Interviews were transcribed and subjected to systematic qualitative analyses that identified common themes within each age group for each conceptual domain. For Toddlers, interviews relied heavily on parents and the biggest concerns were found in the physical and functional domains. Young Children expressed that their biggest issues related to voice were physical ("run out of air," "sometimes voice does not work"). Ninety percent of Young Children were repeatedly asked to use a quieter voice. Emotional factors and physical factors were prominent in the interviews of School-Aged Children and Adolescents. Children and Adolescents often felt that their dysphonic voice received undue attention and also limited their participation in important events. Anger, sadness, and frustration were also expressed. Chronic dysphonia negatively affects the lives of children. This work will serve as the basis for development of a valid, reliable, and age-appropriate measure of voice-related quality of life in children.     

Surface hydrophobicity does not identify ulcerogenic Helicobacter pylori strains isolated from children and adolescents

Helicobacter pylori is a recently recognized bacteria which colonizes the stomach and causes gastritis, gastric cancers and peptic ulceration. However gastric and duodenal ulcers occur in only a minority of H. pylori-infected individuals. Surface hydrophobicity is an important virulence factor of many pathogenic bacteria since it is known to be involved in mediating mucosal adherence. In this study, surface hydrophobicity of H. pylori strains originally isolated from children and adolescents was correlated with gastroduodenal pathology including both endoscopic evidence of duodenal ulceration and histologic evidence of duodenitis. Contact angle measurements on 11 H. pylori isolates were used to characterize surface hydrophobicity. Axisymetric drop-shape analysis revealed contact angles ranging from 7.5 to 15.3°. Contact angles of the strains isolated from patients with duodenal ulcers (11.9±2.6°) were not different from values in isolates obtained from children with gastritis alone (8.9±5.2°; P=0.16). Contact angles of H. pylori isolated from patients with and without duodenitis were also comparable (10.9±2.8° and 10.0±9.6°; P=0.69). These findings indicate that additional virulence properties likely are required for H. pylori to induce peptic ulceration in infected humans.