Socially Shared Regulation of Learning and Quality of Talk: Age Differences in Collaborative Group Work in Classroom Contexts.

Collaborative group work has been recognized as a way of fostering the development of metacognition and self-regulation. Moreover, it has been claimed that these regulatory processes have an interpersonal level in which the regulation of the activity is shared with others (Iiskala et al., 2004). There has also been a considerable body of research on talk within small groups in the classroom. This approach has built a considerable amount of research, given the demonstrated effect of certain types of talk on academic learning. However, very few studies look at both aspects of collaboration (Mercer, 2013). The present research aims to investigate the relationship between socially shared regulation of learning (SSRL) and type of talk. Two hundred and thirty-one groups of three students were videotaped solving a problem in collaboration. Videos were analyzed qualifying exploratory talk and two dimensions of SSRL: metacognitive regulation and symmetry and reciprocity. Results show that the dimensions of SSRL and quality of talk correlate significantly when the whole sample is considered. However, when the sample is segmented by age, differential patterns start to emerge. Theoretical, methodological, and practical implications are discussed.

Vascular anatomy in the lumbar spine investigated by three-dimensional computed tomography angiography: the concept of vascular window.

OBJECTIVE: To report an in vivo anatomic evaluation of prevertebral vessels in the lumbar spine using three-dimensional (3D) computed tomography (CT) angiography and to develop the concept of vascular window for surgical access to L4-5 and L5-S1 disks. METHODS: In 146 patients who were scheduled for anterior lumbar spine surgery, 3D CT angiography was performed preoperatively. Spinal disorders included degenerative disk disease (n = 120) and low-grade spondylolisthesis (n = 26). 3D reconstructions were obtained using the volume-rendering technique. Level of aortic bifurcation and iliocavum confluence, presence of the ascending iliolumbar vein, presence of the central sacral vessels, and anatomic variations were analyzed. A vascular window at L5-S1 was defined as the "free vascular" area for the anterior part of the L5-S1 disk. A vascular window at L4-L5 was defined as the "free vascular" area for the left anterolateral part of the L4-5 disk. RESULTS: The level of aortic bifurcation was most often observed at L4 (64%). The iliocavum confluence occurred most frequently at L5 (44%). The iliolumbar ascending vein and central sacral vessels were identified in 84% and 72% of cases. Five (3.5%) anatomic variations were noted: right internal iliac vein draining into the left common iliac vein in two cases and tortuous vessels in three cases. A vascular window was measured to 34.5 mm ± 12 at L5-S1 and to 23 mm ± 8 at L4-L5. The vascular window was <25 mm in approximately one in four patients at L5-S1 and in approximately two in three patients at L4-L5. CONCLUSIONS: This study confirms that vascular anatomy in the lumbar spine is characterized by a great variability that has significance for preoperative assessment. 3D CT angiography allowed for an effective evaluation of the relationships between the prevertebral vessels and the intervertebral disks at L4-L5 and L5-S1. Although adherence of vessels to the anterior ligament cannot be predicted by this technique, the concept of vascular windows investigated preoperatively by CT angiography could be helpful in predicting the need for vessel mobilization during anterior lumbar spine surgery.

Off-pump coronary bypass surgery for left main coronary artery stenosis 10 years after heart transplantation: case report.

A patient with asymptomatic left main coronary artery stenosis 10 years after heart transplantation was treated successfully with off-pump coronary bypass surgery using both mammary arteries. New advances in bypass surgery may decrease the risk of revascularization in cardiac transplant recipients.

Prospective comparison between total sternotomy and ministernotomy for aortic valve replacement.

Ministernotomy (MS) is an alternative for total sternotomy (TS) in aortic valve replacement. We compared these two approaches for results and adverse effects in a prospective study. From January to December 2000, 100 patients who underwent aortic valve replacement were included in two groups of 50 according to the surgical approach that used MS or TS; one senior surgeon performed all cases in each group. Valvular pathologies were either stenosis or insufficiency. Mean age was 63 +/- 14 years in MS, 67 +/- 12 in TS (p = ns). NYHA class was 2.7 +/- 0.5 in MS, 2.8 +/- 0.6 in TS (p = ns). Left ventricular ejection fraction was 58 +/- 12% in MS, 57 +/- 12% in TS (p = ns). There was a significant difference between MS and TS in aortic cross-clamping (66 +/- 14 min vs 48 +/- 9 min) and cardiopulmonary bypass (88 +/- 18 min vs 69 +/- 10 min, p < 0.01), but not in intervention times (2.8 +/- 0.4 hours vs 2.7 +/- 0.4 hours). Mean intensive care stay was reduced in MS (1.7 +/- 1.6 days vs 2.6 +/- 6 days, p < 0.05). Intubation times (12 +/- 7 hours vs 14 +/- 9 hours), 24 hours bleeding (394 +/- 219 mL vs 465 +/- 318), reintervention for hemostasis (4% vs 2%), rhythmic complications (14% vs 14%), and mortality at 1 month (2% vs 2%) were comparable in MS and TS. In aortic valve surgery, ministernotomy is technically more demanding and needs more time. It is as safe and as effective as conventional sternotomy but its eventual benefits, excepting upon cosmesis, are still to be defined.

Limits of arterial myocardial revascularization.

A prospective study of myocardial blood perfusion after coronary artery bypass graft (CABG) was conducted in two groups of patients. In group 1, a two-year assessment by exercise thallium myocardial scintigraphy without medical treatment was performed in 122 patients who consecutively underwent CABG with exclusive use of both internal mammary arteries (IMA) and gastroepiploic artery (GEA). In group 2, myocardial function and perfusion were determined by radionuclide investigations performed before and one year after CABG in 100 patients with preoperative LV dysfunction (defined as LV ejection fraction (LVEF) less than 0.40), comparing results of myocardial revascularization performed with either exclusive arterial grafts (arterial group, 54 patients) or one arterial graft (IMA) associated with a sequential vein graft (vein group, 46 patients). In group 1, 21% of patients presented silent residual electric ischemia during exercise stress testing and 26% had reversible scintigraphic ischemic defect despite complete revascularization, 18% of those in the inferior wall bypassed with GEA and 8% in the anterior wall bypassed with the right IMA. In group 2, the significant preoperative ischemia significantly decreased in both the vein group and the arterial group. LV function was significantly improved in the vein group; in contrast there was no modification of LV function in the arterial group. A multivariate analysis showed that the surgical technique used and the preoperative LVEF were independent prognostic factors of the postoperative myocardial outcome, with a positive impact of the vein use on the postoperative myocardial function recovery. It is important to recognize that arterial grafts have some limitations in the ability to supply blood flow for coronary circulation that may induce postoperatively silent residual myocardial ischemia and a lack of LV function recovery.