Growing wheat in Biosphere 2 under elevated CO2: observations and modeling.

Spring wheat (Triticum aestivum L., cv. Yecora Rojo) was grown in the intensive agricultural biome (IAB) of Biosphere 2 during the l995-l996 winter/spring season. Environmental conditions were characterized by a day/night temperature regime of 27/17 degrees C, relative humidity (RH) levels around 45%, mean atmospheric CO2 concentration of 450 ppmv, and natural light conditions with mean intensities about half of outside levels. Weekly samples of above-ground plant matter were collected throughout the growing season and phenological events recorded. A computer model, CERES-Wheat, previously tested under both field and controlled conditions, was used to simulate the observed crop growth and to help in data analysis. We found that CERES-Wheat simulated the data collected at Biosphere 2 to within 10% of observed, thus suggesting that wheat growth inside the IAB was comparable to that documented in other environments. The model predicts phenological stages and final dry matter (DM) production within l0% of the observed data. Measured DM production rates, normalized for light absorbed by the crop. suggested photosynthetic efficiencies intermediate between those observed under optimal field conditions and those recorded in NASA-Controlled Ecological Life-Support Systems (CELSS). We suggest that such a difference can be explained primarily in terms of low light levels inside the IAB, with additional effects due to elevated CO2 concentrations and diffuse light fractions.

Description of Hemicycliophora biosphaera n. sp. from Arizona (Nemata: Criconematidae).

Hemicycliophora biosphaera n. sp. (Nemata: Criconematidae) was found in soil from a fallow field plot within the Biosphere 2 Center, Oracle, Arizona. The nematode species is characterized by continuous and irregular breaks in transverse striae in the lateral field, smooth annules, a rounded-truncate lip region with rounded anterior margins, three lip annules, first labial annule elevated and widened laterally, dome-shaped and elevated labial disc, stylet length (76-97 (mum), VA%T value (30-59), 234-273 body annules, and tail with a terminus offset, cylindrical to slightly conoid digit. Hemicycliophora biosphaera n. sp. most closely resembles H. armandae but differs from it in body width (30-39 vs. 38-54 mum), stylet length (76-97 vs. 95-119 mum), greater number of annules between the excretory pore and esophagus base (4-16 vs. 2), length of the tail terminal spike (16-28 vs. 32 mum), lower Rvan value (9-15 vs. 16), and indistinct spetanatheca vs. distinct spermatheca.

The Biosphere 2 Global Change Testbed world wide web server: closed system research and education using the Internet

NASA: At this time, a fully materially closed system of large scale and complexity has not yet been built. However, Biosphere 2--a unique "living" Earth laboratory--is an example of a large (3.15 acres) and biologically complex (several thousand terrestrial plant species) system that can be operated with minimal exchange of ambient substances (annual exchange of materials is estimated to be approximately 10%). Biosphere 2 provides a multidisciplinary platform for scientific studies related to both Earth system processes and microcosms of the Earth that may be transported into space. The scale and versatility of the facility make Biosphere 2 a unique place to support integrated research and educational activities. The Biosphere 2 Global Change Testbed world wide web server has been developed to facilitate such activities by disseminating information about the facility, as well as current research and education efforts. Currently, these efforts focus of studies on carbon and other elemental cycles, coral reef ecology and physiology, stable isotopic research, studies in biodiversity, and ecophysiological studies of plant responses to elevated CO2. The Biosphere 2 Global Change Testbed web server is briefly described, and goals for use of the server to promote research and education endeavors are outlined.^ieng

Staging laparotomy for endometrial carcinoma: assessment of retroperitoneal lymph nodes.

The surgical staging scheme for uterine corpus cancer adopted in 1988 by the International Federation of Gynecology and Obstetrics assigns patients with tumor spread to retroperitoneal lymph nodes to stage IIIC. However, a recommended approach to the detection of lymph node metastasis is not delineated. As part of an ongoing project to assess the value of surgical staging procedures, we reviewed the techniques of lymph node evaluation in 295 at-risk patients. Cases included clinical stage I patients whose preoperative biopsies demonstrated grade 2 or 3 adenocarcinoma or papillary serous, clear cell, or mixed carcinoma. We arbitrarily divided the retroperitoneal space into 10 lymphatic zones: left and right para-aortic, common iliac, external iliac, hypogastric, and obturator. Eighty-two percent of patients had some type of node sampling that involved a mean of three zones. Thirty-three of 244 sampled cases (13.5%) had nodal metastases: 20 had gross involvement and 13 had microscopic. We stratified patients into three groups: (1) those who had no node sampling (n = 51), (2) those with some nodes biopsied (n = 193), and (3) those whose node sampling included a minimum of one para-aortic plus at least one right and left pelvic specimen (n = 51). Retroperitoneal recurrences thought to originate from lymph node sites were identified for the "node-negative" patients in each group: Group 1, 4/51 (8%); Group 2, 9/173 (5%); and Group 3, 0/38 (0%). Lymphatic site failures were seen in 8 of 33 (24%) patients with biopsy-proven metastases. We found that failure to systematically sample pelvic and para-aortic nodes results in a small, but real, risk of undetected extrauterine metastasis. A selective approach to sampling that includes biopsy from both para-aortic and bilateral pelvic lymphatic zones appears to provide an accurate estimate of true node negativity. Further evaluation of this approach is warranted.

Staging laparotomy for endometrial carcinoma: assessment of peritoneal spread.

To evaluate surgical staging procedures in women with endometrial carcinoma, we examined the techniques used to assess the peritoneal cavity in 295 clinical stage I patients treated between 1985 and 1993. These patients were felt to be at increased risk for extrauterine disease because of significant myometrial invasion, high-grade (2 or 3), or variant histology (papillary serous, clear cell, or mixed). Patients had a mean of two intraperitoneal samples taken: 224 patients (76%) had at least an omental biopsy and peritoneal cytology. Additional peritoneal biopsy sites included pericolic gutters (50), pelvic peritoneum (45), bowel serosa/mesentery (24), diaphragm (22), appendix (11), and adhesions (7). At the time of staging laparotomy, 22 patients (7.5%) had gross evidence of peritoneal spread, which was readily confirmed by directed biopsy. In the 273 women without gross peritoneal disease, 3 (1%) had occult metastases detected by routine biopsy, 3 (1%) had microscopic metastases in palpably abnormal biopsies, and 22 had positive cytology as the only evidence of peritoneal disease. Only three operative complications were potentially attributable to peritoneal assessment: cystotomy (1), partial small bowel obstruction (1), and ileus (1). Peritoneal failures have been noted in 12 patients over a mean follow-up interval of 39 months. Seven of these patients had obvious peritoneal disease at laparotomy. Two of the remaining 5 had optimal peritoneal sampling and represent false-negative cases. A staging laparotomy that included total abdominal hysterectomy with adnexal resection, cytology, omental biopsy, and biopsy of grossly abnormal sites would have potentially identified all patients with known peritoneal disease. Routine biopsy of other grossly normal peritoneal sites is associated with extremely low yield and is not recommended.

Isotopic evidence for neogene hominid paleoenvironments in the kenya rift valley.

Bipedality, the definitive characteristic of the earliest hominids, has been regarded as an adaptive response to a transition from forested to more-open habitats in East Africa sometime between 12 million and 5 million years ago. Analyses of the stable carbon isotopic composition (delta(13)C) of paleosol carbonate and organic matter from the Tugen Hills succession in Kenya indicate that a heterogeneous environment with a mix of C3 and C4 plants has persisted for the last 15.5 million years. Open grasslands at no time dominated this portion of the rift valley. The observed delta(13)C values offer no evidence for a shift from more-closed C3 environments to C4 grassland habitats. If hominids evolved in East Africa during the Late Miocene, they did so in an ecologically diverse setting.