如何巧妙应对课堂教学中出现的意外

布卢姆说：＂人们无法预料到教学所产生成果的全部范围。＂课堂教学过程中,总会遇到很多始料未及的＂意外＂。由于生物活动开放性太强,学生思维旁逸斜出,即使课前预设再充分,一节课也会出现节外生枝的现象。     

课堂“意外”应对之思考

善待课堂教学中的"意外",让课堂成为学生的生命历程,让生命的活力在这样的课堂中更加富有情趣和魅力。延迟评价判断,会在课堂"意外"中收获"意外"。     

脑血管意外的紧急救护

脑血管疾病是神经系统的常见疾病,本病特点是发病急、病情重,病死率和致残率均较高。肾急救护降低病死率和致残率是脑血管疾病目前亟待解决的问题。本文就近两年来我院神经内科212例脑血管患者的救治和临床护理,从脑血管意外的诊断、诱发因素、救治原则等方面分别进行了概述,进一步分析了脑血管意外的救治及防护,对减少并发症及后遗症,提高治愈率及患者的生存质量有一定的临床意义。     

脑血管意外的紧急救护

脑血管疾病是神经系统的常见疾病,本病特点是发病急、病情重,病死率和致残率均较高。紧急救护降低病死率和致残率是脑血管疾病目前亟待解决的问题。本文就近两年来我院神经内科212例脑血管患者的救治和临床护理,从脑血管意外的诊断、诱发因素、救治原则等方面分别进行了概述,进一步分析了脑血管意外的救治及防护,对减少并发症及后遗症,提高治愈率及患者的生存质量有一定的临床意义。     

无菌检查的意外污染探讨

无菌检查法系指检查药物与敷料、器械是否无菌的一种方法。各国药典对无菌试验的具体操作 ,如所用的方法、培养基、培养时间、结果判断等均作了详细的规定。但未见到为了防止操作中的意外污染 ,应选用的仪器、设备和使用方法的规定。中国药典规定 :“无菌检查的全过程应严格遵守无菌操作 ,防止微生物的污染”。目前 ,我国无菌检查一般都在无菌室或超净工作台上操作 ,但国内的做法在检查过程中仍存在着较大意外污染的可能性 ;如样品容器外壁消毒不当 ,折颈时玻璃屑掉入 ,样品转移 ,滤膜过滤、淋法、滤膜转移等操作以及取样的针头或吸管均有意…     

2500例脑血管意外预测的结果分析

脑血管意外又叫中风,是中老年人多发病。死亡率和致残率极高,严重危害中老年人健康。我科从88年以来,采用无锡石塘湾医疗电子仪器厂生产的,血液流变学系列仪器,根据临床上18个危险因子和血液流变学多项指标及血三脂检查数值,对2500例患者及表面健康者开展了中风预测,结果显示:脑溢血后遗症阳性率>高血压,脑血栓>高血压、冠心病>脑血管供血不足>其它疾病。充分说明脑血管意外的疾病其阳性率明显大于其它组,中风预测及时发现和检出危险因子,为探讨其临床工作中的应用价值,现将结果分析如下:     

急性脑血管意外患者心电图的变化

对我院住院部在1993～1998年间收治的80例急性脑血管意外患者的心电图临床资料进行分析总结,结果表明急性脑血管意外的患者特别是脑出血和蛛网膜下腔出血的大部分患者可并发心电图的改变。现报告如下。1　临床资料　　本组病例男60例,女20例。其中脑出血32例,蛛网膜下腔出血6例,脑血栓30例,脑栓塞12例。患病年龄33～81岁,平均年龄62岁,均在发病后2h至3天内入院,经CT检查确诊,24h内作心电图检查。　　80例急性脑血管意外心电图检查,发病后急性期有改变的为55例,占69%,其中脑出血20例,占62%(20/32),蛛网膜下腔出血6例均有改变,脑血栓19例,占6…     

生物课堂教学中有效互动的关键要素

追求有效教学,从课堂教学层面分析,有效的课堂互动是其表征之一。反思近几年的课堂教学,关注课堂互动行为,实现有效的课堂互动,需要从教师、教材、学生等多方面进行思考。     

联系生活提高高中生物课堂教学的有效性

教学要回归生活是新课程改革的重要理念之一,教师发挥主导作用,改革教学方法,以学生为主体,让学生在生活中学习,通过学习更好地生活,从而更灵活地掌握知识、应用知识。联系生活是有效教学的一种重要教学策略。本文从导入新课、创设情境、开展活动、设计练习等方面论述联系生活教学策略在高中生物教学中的应用。     

设计情境,创有效课堂教学——谈高中生物课堂教学情境的设计策略

夸美纽斯说过,知识始于感官。可见,感官对于知识的构建的重要性。而情景教学可以首先满足学生的感官,让学生在真实、生动、形象的情境中,观察生物实验想象、动手操作实验、构建知识。     

How LCA studies deal with uncertainty

In recent years many workers have examined the implications of various sources of uncertainty for the reliability of Life Cycle Assessment (LCA). Indeed, the International Standardization Organization (ISO) has recognised the relevance of this work by including several cautionary statements in the ISO 14040 series of standards. However, in practice, there is a risk that the significance of these uncertainties for the results of an LCA could be overlooked as practitioners strive to complete studies on time and within budget. This paper presents the findings of a survey of LCA studies we made to determine the extent to which the problem of uncertainty had been dealt with in practice. This survey revealed that the significance of the limitations on the reliability of LCA results given in the standards has not been fully appreciated by practitioners. We conclude that the standards need to be revised to ensure that LCA studies include at least a qualitative discussion on all relevant aspects of uncertainty.     

How to deal with neglected tropical diseases in the light of an African ethic

Many countries in Africa, and more generally those in the Global South with tropical areas, are plagued by illnesses that the wealthier parts of the world (mainly ‘the West’) neither suffer from nor put systematic effort into preventing, treating or curing. What does an ethic with a recognizably African pedigree entail for the ways various agents ought to respond to such neglected diseases? As many readers will know, a characteristically African ethic prescribes weighty duties to aid on the part of those in a position to do so, and it therefore entails that there should have been much more contribution from the Western, ‘developed’ world. However, what else does it prescribe, say, on the part of sub‐Saharan governments and the African Union, and are they in fact doing it? I particularly seek to answer these questions here, by using the 2013‐16 Ebola crisis in West Africa to illustrate what should have happened but what by and large did not.     

How meiotic cells deal with non-exchange chromosomes

The chromosomes which segregate in anaphase I of meiosis are usually physically bound together through chiasmata. This association is necessary for proper segregation, since univalents sort independently from one another in the first meiotic division and this frequently leads to genetically unbalanced offspring. There are, however, a number of species where genetic exchanges in the form of meiotic cross-overs, the prerequisite of the formation of chiasmata, are routinely missing in one sex or between specific chromosomes. These species nevertheless manage to segregate these non-exchange chromosomes. There are four direct modes for associating achiasmatic chromosomes: (a) modified SC, (b) adhesion of chromatids comparable to somatic pairing, (c) ‘stickiness’ of heterochromatin or (d) specific ‘segregation bodies’, consisting of material structurally different from chromatin. There is also the possibility that the spindlepossibly joining forces with the kinetochores-carries out the faithful segregation of univalents which are not directly physically attached to one another. Finally, amphitelic orientation of univalents in metaphase I and pairing of the chromatids in meiosis II appear to ensure correct segregation as well.     

How to deal with oxygen radicals stemming from mitochondrial fatty acid oxidation

Oxygen radical formation in mitochondria is an incompletely understood attribute of eukaryotic cells. Recently, a kinetic model was proposed, in which the ratio between electrons entering the respiratory chain via FADH₂ or NADH determines radical formation. During glucose breakdown, the ratio is low; during fatty acid breakdown, the ratio is high (the ratio increasing—asymptotically—with fatty acid length to 0.5, when compared with 0.2 for glucose). Thus, fatty acid oxidation would generate higher levels of radical formation. As a result, breakdown of fatty acids, performed without generation of extra FADH₂ in mitochondria, could be beneficial for the cell, especially in the case of long and very long chained ones. This possibly has been a major factor in the evolution of peroxisomes. Increased radical formation, as proposed by the model, can also shed light on the lack of neuronal fatty acid oxidation and tells us about hurdles during early eukaryotic evolution. We specifically focus on extending and discussing the model in light of recent publications and findings.     

How greater mouse-eared bats deal with ambiguous echoic scenes

Echolocating bats have to assign the received echoes to the correct call that generated them. Failing to do so will result in the perception of virtual targets that are positioned where there is no actual target. The assignment of echoes to the emitted calls can be ambiguous especially if the pulse intervals between calls are short and kept constant. Here, we present first evidence that greater mouse-eared bats deal with ambiguity by changing the pulse interval more often, in particular by reducing the number of calls in the terminal group before landing. This strategy separates virtual targets from real ones according to their change in position. Real targets will always remain in a constant position, and virtual targets will jitter back and forth according to the change in the time interval.     

How does an eclosing fly deal with obstacles?

ABSTRACT. Stereotyped eclosion behaviour of Sarcophaga bullata Parker (Diptera, Sarcophagidae) consists of two different repetitive sequences of movements. One, which is instrumental for making forward progress in extricating the body from the puparium or for digging through the soil, is called the programme for forward movement (PFM). The other, which is performed as a response to an obstruction, is called the programme for obstruction removal (POR). The initial and final phases of each repetitive sequence are identical in both programmes, the sequences differing only in the middle portion. In the POR, the locomotor elements of the PFM sequence (peristalsis) are substituted by a train of repetitive expansions of the ptilinum, which are caused by simultaneous contractions of the abdominal and thoracic muscles. These ptilinal movements function as an air hammer against the obstruction. Switching from the PFM to POR can be experimentally induced by a rough mechanical stimulation of the head (squeezing, pushing against a barrier) but not by gentle tactile stimulation of the ptilinum or antennae. The critical period for induction of the POR is in the phase of the PFM sequence at which the two programmes diverge. A constant mechanical stimulus is necessary for a sustained performance of the whole POR. A hypothetical scheme of the neural basis of this behaviour is suggested.