Mathematical learning difficulties and PASS cognitive processes

This study examined the relationships between mathematical learning difficulties (MLD) and the planning, attention, simultaneous, successive (PASS) theory of cognitive processing. The Cognitive Assessment System (CAS) was used to measure the PASS processes for a group of 267 Dutch students with MLD who attended either general or special education. The results showed that students with MLD performed lower than their peers on all CAS scales and that the MLD group contained many students with cognitive weaknesses in planning or successive processing. Moreover, students who had specific difficulties with the acquisition of basic math facts, the automatization of such facts, or word-problem solving were found to have distinct PASS cognitive profiles. In order to investigate the relationships between cognitive abilities and improvement in the mastery of basic math facts and problem solving, 165 of the students with MLD were given a special multiplication intervention. It appeared that the effectiveness of this particular intervention did not differ across the groups of students with specific cognitive weaknesses.     

Experiential influences on multimodal perception of emotion

The impact of 2 types of learning experiences on children's perception of multimodal emotion cues was examined. Children (aged 7-12 years) were presented with conflicting facial and vocal emotions. The effects of familiarity were tested by varying whether emotions were presented by familiar or unfamiliar adults. The salience of particular emotional expressions was tested by contrasting the performance of physically abused and nonabused children. Children exhibited a preference for auditory expressions produced by their mothers but not by strangers. Additionally, abused children were biased to rely on auditory cues when their own abusive mother was expressing anger. These results are discussed in terms of the impact of both typical and atypical early experiences on the development of emotion perception.     

Performance factors in associative learning: Assessment of the sometimes competing retrieval model

Previous simulations revealed that the sometimes competing retrieval model (SOCR; Stout & Miller, Psychological Review, 114, 759-783, 2007), which assumes local error reduction, can explain many cue interaction phenomena that elude traditional associative theories based on total error reduction. Here, we applied SOCR to a new set of Pavlovian phenomena. Simulations used a single set of fixed parameters to simulate each basic effect (e.g., blocking) and, for specific experiments using different procedures, used fitted parameters discovered through hill climbing. In simulation 1, SOCR was successfully applied to basic acquisition, including the overtraining effect, which is context dependent. In simulation 2, we applied SOCR to basic extinction and renewal. SOCR anticipated these effects with both fixed parameters and best-fitting parameters, although the renewal effects were weaker than those observed in some experiments. In simulation 3a, feature-negative training was simulated, including the often observed transition from second-order conditioning to conditioned inhibition. In simulation 3b, SOCR predicted the observation that conditioned inhibition after feature-negative and differential conditioning depends on intertrial interval. In simulation 3c, SOCR successfully predicted failure of conditioned inhibition to extinguish with presentations of the inhibitor alone under most circumstances. In simulation 4, cue competition, including blocking (4a), recovery from relative validity (4b), and unblocking (4c), was simulated. In simulation 5, SOCR correctly predicted that inhibitors gain more behavioral control than do excitors when they are trained in compound. Simulation 6 demonstrated that SOCR explains the slower acquisition observed following CS-weak shock pairings.     

发射光谱法测定化探样品中的银锡

发射光谱法同时测定化探样品中的银锡,以焦硫酸钾、氟化钠、氧化铝、石墨粉为缓冲剂,锗为内标,其检出限为Ag0.02μg/g,Sn1.0μg/g。通过多次实验,对实验条件进行选择和优化。采用国家一级标准物质的样品验证,测定结果与标准值相符。     

注射用盐酸头孢吡肟的RP-HPLC测试

建立注射用盐酸头孢吡肟含量测定的RP-HPLC方法。ODS色谱柱250×4.6mm（i.d.）5μm;0.04mol/L醋酸铵（冰醋酸调节pH至5.0）-甲醇（92：8）为流动相,流速为1.0ml/min,检测波长为256nm。流速为1.0ml/min。盐酸头孢吡肟在10.5～84.0μg/ml浓度范围内,其峰面积与浓度呈良好线性关系（r=0.9993）,精密度RSD为0.5%。平均回收率为98.90%,RSD为0.34%,检测限为1.5ng。本法简便、快速、准确、专属性强,可用于注射用盐酸头孢吡肟的含量测定及有关物质检查。     

遇到娇生惯养的学生怎么办

由于人民生活水平的提高,独生子女的增加,小学生里面娇生惯养的学生越来越多。这是小学教育中一个新问题。 娇生惯养的学生的特征:从小生活舒服,害怕吃苦,自私自利,事事要“拔尖儿”,爱听表扬,不爱听批评,自我管理能力差,遇到困难就哭鼻子,     

谈班主任的“说”功

一次,著名京剧表演艺术家马连良在同剧作家汪曾祺切磋剧本唱段安排时说：“不该唱的时候去唱,比该唱时不唱,还令观众难受。”马连良说的是京剧艺术,但我觉得这对做班务工作的同志同样适用。我们有一些班主任,特别是刚走上教学岗位的青年同志,责任心很强,能整天沉到...     

Somatotype and size of elite female basketball players

The aim of this study was to compare the somatotype and size of elite female basketball players in terms of playing position and team performance. Anthropometry and somatotype data were collected on 168 players from 14 countries before the Women's World Basketball Championship, Australia, 1994. There were 64 guards (mean +/- s: age 25.4 +/- 3.3 years, height 1.72 +/- 0.06 m, mass 66.1 +/- 6.2 kg, somatotype = 2.9-3.9-2.6), 57 forwards (age 25.2 +/- 3.8 years, height 1.81 +/- 0.06 m, mass 73.3 +/- 5.9 kg, somatotype = 2.8-3.5-3.2) and 47 centres (age 24.1 +/- 3.1 years, height 1.90 +/- 0.06 m, mass 82.6 +/- 8.2 kg, somatotype = 3.2-3.1-3.4). Mean somatotypes by position were significantly different (F = 7.73, P < 0.01). Guards had greater mesomorphy than centres and less ectomorphy than forwards and centres. When discriminant function analysis was applied to endomorphy, mesomorphy, ectomorphy, age, height and mass, only height, mass and ectomorphy entered (Wilks' lambda = 0.351, F = 31.40, P < 0.000), 70% of the variance was accounted for, and 72% of players were correctly classified. In the four top versus four bottom teams, guards were taller and more ectomorphic, forwards were taller, with lower mesomorphy and higher ectomorphy, and centres did not differ. Thus there are some differences in somatotypes by position and team placing, but the combination of height, mass and ectomorphy provide the best differentiation by position.     

Altitude and endurance training

The benefits of living and training at altitude (HiHi) for an improved altitude performance of athletes are clear, but controlled studies for an improved sea-level performance are controversial. The reasons for not having a positive effect of HiHi include: (1) the acclimatization effect may have been insufficient for elite athletes to stimulate an increase in red cell mass/haemoglobin mass because of too low an altitude (< 2000-2200 m) and/or too short an altitude training period (<3-4 weeks); (2) the training effect at altitude may have been compromised due to insufficient training stimuli for enhancing the function of the neuromuscular and cardiovascular systems; and (3) enhanced stress with possible overtraining symptoms and an increased frequency of infections. Moreover, the effects of hypoxia in the brain may influence both training intensity and physiological responses during training at altitude. Thus, interrupting hypoxic exposure by training in normoxia may be a key factor in avoiding or minimizing the noxious effects that are known to occur in chronic hypoxia. When comparing HiHi and HiLo (living high and training low), it is obvious that both can induce a positive acclimatization effect and increase the oxygen transport capacity of blood, at least in 'responders', if certain prerequisites are met. The minimum dose to attain a haematological acclimatization effect is > 12 h a day for at least 3 weeks at an altitude or simulated altitude of 2100-2500 m. Exposure to hypoxia appears to have some positive transfer effects on subsequent training in normoxia during and after HiLo. The increased oxygen transport capacity of blood allows training at higher intensity during and after HiLo in subsequent normoxia, thereby increasing the potential to improve some neuromuscular and cardiovascular determinants of endurance performance. The effects of hypoxic training and intermittent short-term severe hypoxia at rest are not yet clear and they require further study.