Maggie and her students: Talking and reasoning in a reform-based mathematics classroom

In this qualitative case study, I explored how Maggie, the teacher, and her students used language to advance students\u27 conceptual understanding of mathematics in a reform-based mathematics classroom. Specifically I sought to describe how Maggie\u27s reform-based mathematics classroom environment impacted the quantity and quality of mathematical language spoken by her students. Maggie\u27s eighth-grade mathematics classroom was observed during a course of study on data and statistics. Three semi-structured interviews with Maggie, artifacts provided by her, and fourteen 52-minute classroom lessons, supported with field notes, were analyzed. Environmental themes were revealed as they related to Maggie, her beliefs, goals, knowledge, and what she said. Maggie\u27s talk was framed by five productive teacher-talk moves. The quantity of student talk was analyzed according to three variations of the three-phase reform-based mathematics lesson (Direct Instruction, Guided Discovery, Open-Ended Exploration) and three talk formats (Whole-Class Discussion, Partner Talk, Small-Group Discussion). Due to the Maggie\u27s diminished role during Partner Talk and Small-Group Discussion, an in-depth analysis was conducted to determine what students were talking about when they worked independently. This revealed a qualitative change over the course of the unit. Further analysis revealed that students engaged in two mathematical Discourses: Procedural Discourse and Conceptual Discourse. Since the focus of this study was on how language was used to advance students\u27 conceptual understanding of mathematics, this type of talk became a focus of further analysis. Ten categories of students\u27 mathematical reasoning emerged from the data. This study provides a rich description of a reform-based mathematics classroom environment, and the quantity and quality of student talk impacted by it. Implications for educational leadership, literacy education, mathematics education, and teacher education, as well as recommendations for future studies, are shared

Laparoscopic and Other Intrafascial Hysterectomy Techniques or Mucosal Ablation—A Choice for Maximum Organ Conservation

The operative methods of total uterine mucosal ablation (TUMA) as well as new abdominal and vaginal hysterectomy techniques are described. Classic intrafascial serrated edged macro-morcellator (SEMM) hysterectomy (CISH) by pelviscopy or laparotomy and intrafascial vaginal hysterectomy (IVH) are techniques that allow the nerve and the blood supply of the pelvic floor to remain intact, mainly because only the ascending branches of the uterine arteries are ligated. TUMA avoids the removal of the uterus altogether and is reserved for hypermenorrhea or menorrhagia without major enlargement of the uterus. Both CISH and IVH reduce the physical trauma of hysterectomy considerably and have the advantages of the supravaginal technique. Prophylaxis against cervical stump carcinoma is assured by coring out the cervix with the SEMM. In patients in whom both procedures are possible, IVH is preferred because it combines the minimal trauma and short operative time of vaginal hysterectomy. The decreased diameter of the cervix after coring out greatly simplifies this type of vaginal hysterectomy, the technique that has always been favored because of its short operative times and minimal trauma

Sonographic and Histological Morphometry of the Uterine Cervix—An Assessment of Laparoscopic and Other lntrafascial Hysterectomy Techniques

New abdominal and vaginal hysterectomy techniques, such as classic intrafascial serrated edged macro-morcellator (SEMM) hysterectomy (CISH), by pelviscopy/laparoscopy or laparotomy, and intrafascial vaginal hysterectomy (IVH), are both essentially supravaginal techniques. It has been claimed that they give a prophylaxis against cervical stump carcinoma by coring out the cervix with the SEMM. We set out to answer two questions: 1) How can vaginosonography help to choose an adequate SEMM diameter so that the cervical mucosa and transformation zone are completely removed, and 2) How often do cervical glands remain after the coring out procedure? We were able to show a good correlation between sonographic and histological morphology by giant and serial sections. In 253 CISH operations, resection of both endocervix and transformation zone was complete in 92.9%. Dysplasias were always removed completely; only 18 cervical cores exhibited healthy glands (retention cysts) in the resection margin. Therefore, CISH procedures should be able to prevent most of the cervical stump carcinomata that follow traditional supravaginal hysterectomy, but only long-term follow-up will give the final proof

Late Cenozoic tephrostratigraphy offshore the southern Central American Volcanic Arc: 2. Implications for magma production rates and subduction erosion

Pacific drill sites offshore Central America provide the unique opportunity to study the evolution of large explosive volcanism and the geotectonic evolution of the continental margin back into the Neogene. The temporal distribution of tephra layers established by tephrochonostratigraphy in Part 1 indicates a nearly continuous highly explosive eruption record for the Costa Rican and the Nicaraguan volcanic arc within the last 8 M.y. The widely distributed marine tephra layers comprise the major fraction of the respective erupted tephra volumes and masses thus providing insights into regional and temporal variations of large-magnitude explosive eruptions along the southern Central American Volcanic Arc (CAVA). We observe three pulses of enhanced explosive magmatism between 0-1 Ma at the Cordillera Central, between 1-2 Ma at the Guanacaste and at >3 Ma at the Western Nicaragua segments. Averaged over the long-term the minimum erupted magma flux (per unit arc length) is ∼0.017 g/ms. Tephra ages, constrained by Ar-Ar dating and by correlation with dated terrestrial tephras, yield time-variable accumulation rates of the intercalated pelagic sediments with four prominent phases of peak sedimentation rates that relate to tectonic processes of subduction erosion. The peak rate at >2.3 Ma near Osa particularly relates to initial Cocos Ridge subduction which began at 2.91±0.23 Ma as inferred by the 1.5 M.y. delayed appearance of the OIB geochemical signal in tephras from Barva volcano at 1.42 Ma. Subsequent tectonic re-arrangements probably involved crustal extension on the Guanacaste segment that favored the 2-1 Ma period of unusually massive rhyolite production