Controlled cortical impact (CCI), using a pneumatically driven impactor to produce traumatic brain injury, has been characterized previously in both the ferret and in the rat. In the present study, we applied this technique to establish and characterize the CCI model of brain injury in another species, the mouse, evaluating cognitive and histopathologic outcome. In anesthetized (sodium pentobarbital, 65 mg/kg) male C57BL mice, we performed sham treatment (no injury, n = 12) or CCI injury (n = 12) at a velocity of 5.7-6.2 m/sec and depth of 1 mm, using a 3-mm diameter rounded-tip impounder, positioned over the left parietotemporal cortex (parasagittal). At this level of injury, we observed highly significant deficits in memory retention of a Morris water maze task 2 days following injury (p < 0.001). Postmortem histopathologic analysis performed at 48 h following injury revealed substantial cortical tissue loss in the region of impact and selective hippocampal neuronal cell loss in the CA2, CA3, and CA3c regions, using Nissl staining. Analysis of degenerating neurons using modified Gallyas silver staining techniques demonstrated consistent ipsilateral injury of neurons in the cortex adjacent to the impact site and in the dentate gyrus of the ipsilateral hippocampus. Bilateral degeneration was observed at the gray matter-white matter interface along the corpus callosum. Glial fibrillary acidic protein (GFAP) immunohistochemistry revealed extensive reactive gliosis appearing diffusely through the bilateral cortices, hippocampi, and thalami at 48 h postinjury. Breakdown of the blood-brain barrier was demonstrated with antimouse IgG immunohistochemistry, revealing extravasation of endogenous IgG throughout the ipsilateral cortex, hippocampus, and thalamus. These results suggest that this new model of parasagittal CCI in the mouse mimics a number of well-established sequelae observed in previously characterized brain injury models using other rodent species. This mouse model may be a particularly useful experimental tool for comparing behavioral and histopathologic characteristics of traumatic brain injury in wild-type and genetically altered mice.
The primary purpose of assessment in an instructional setting is twofold: to determine whether learners have achieved the stated objectives and learner outcomes described in the curriculum and to determine whether educators meet those learning objectives in the classroom. Assessment, quite often, is administered in the form of a written or computerized test or exam. An exam is a measurement instrument designed to measure knowledge and understanding of defined content (Gaberson, 2008). Testing is an important activity for the learner as the learner needs to identify how they performed on the test, and whether test results allow them to progress in their program (Sainsbury & Walker, 2008). Testing is also important for the educator. Testing is a means to identify whether teaching is effective and how well the student comprehends the material. Because testing is a "high-stakes" (Hoachlander, 1998) activity in which students must offer their best performance, it can be anxiety provoking and can negatively affect their performance. There are many reasons why students might underperform on tests, including poor performance related to test anxiety, poor study skills, improper test preparation, language difficulties, and the presence of cultural bias through poorly written questions (Lusk & Conklin, 2003). There is little empirical evidence available on the validity of various testing formats, yet educators still rely heavily on traditional individual testing as a method of evaluation or assessment (Halstead, 2007). An additional complicating factor is that all tests have error; without conducting a proper item analysis, poorly constructed or unvalidated tests can inaccurately reflect student knowledge (Gaberson, 2008). Because of the many disadvantages inherent in traditional testing, alternate testing methods have been explored. One of these is collaborative testing, a relatively recent modality that is becoming more frequently utilized as an alternative. Collaborative Testing The intervention that will be examined in this review is collaborative testing. Collaborative testing is a method in which students work together while taking a written evaluative exam. Collaborative, or cooperative, testing is an umbrella term used to describe a test method different from traditional or individualized testing. Collaborative testing has been utilized in undergraduate, graduate, and post graduate settings. Collaborative testing, which is a student-centered, active learning approach, is also referred to as group testing, double testing, paired testing, cooperative testing, and dyad testing (Centrella-Nigro, 2012). Group testing is the term utilized when a test is administered to more than two students. Generally, in group testing the group consists of three to six students (Centrella-Nigro, 2012; Leight, Saunders, Calkins, & Withers, 2012; Wiggs, 2011). The terms dyad or paired testing are utilized when students are paired with a partner to take an exam (Centrella-Nigro, 2012;
R2 Library is an e-book platform from Rittenhouse Book Distributors. Its titles are not publisher-specific, and there is overlap with other e-book providers. R2 can be searched as a database, and resources (titles) may be directly accessed from an OPAC search. This review will cover administrative set-up and tools; end-user searching and browsing; and personalization tools for the platform. Also covered will be navigation, site structure, and any special features. Information regarding Rittenhouse's model for cost and access will be discussed.
This article is the first part of a two part paper. The first part discusses how the conception of giftedness has changed. The influences of home and school are briefly discussed and the characteristics of very able learners are explored in connection with what parents and teachers need to provide in the way of understanding and support.Part Two of the paper discusses various kinds of curriculum extension programmes discussing the underlying educational assumptions and feasibility of their implementation in a typical school system.
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