Wild bees visiting cucumber on midwestern U.S. organic farms benefit from near-farm semi-natural areas.

Wild bees that provide pollination services to vegetable crops depend on forage resources, nesting sites, and overwintering sites in the agricultural landscape. The scale at which crop-visiting bees use resources in the landscape can vary regionally, and has not been characterized in the Midwestern United States. We investigated the effects of seminatural land cover on wild bee visitation frequency to cucumber (Cucumis sativus L.) and on wild bee species richness on 10 organic farms in Indiana. We estimated the spatial scale at which the effects of land cover were strongest, and also examined the effects of nonlandscape factors on wild bees. The visitation frequency of wild bees to cucumber was positively related to the proportion of seminatural land in the surrounding landscape, and this relationship was strongest within 250 m of the cucumber patch. The species richness of wild cucumber visitors was not affected by land cover at any spatial scale, nor by any of the nonlandscape factors we considered. Our results indicate that wild, crop visiting bees benefit from seminatural areas in the agricultural landscape, and benefit most strongly from seminatural areas within 250 m of the crop field. This suggests that setting aside natural areas in the near vicinity of vegetable fields may be an effective way to support wild, crop-visiting bees and secure their pollination services.

Single incision laparoscopic colectomy: technical aspects, feasibility, and expected benefits.

Background. This paper studied technical aspects and feasibility of single incision laparoscopic colectomy (SILC). Methods. Bibliographic search was carried out up to October 2009 including original articles, case reports, and technical notes. Assessed criteria were techniques, operative time, scar length, conversion, complications, and hospitalization duration. Results. The review analyzed seventeen SILCs by seven surgical teams. A single port system was used by four teams. No team used the same laparoscope. Two teams used two laparoscopes. All teams used curved instruments. SILC time was 116 +/- 34 minutes. Final scar was longer than port incision (31 +/- 7 versus 24 +/- 8 mm; P = .036). No conversion was reported. The only complication was a bacteremia. Hospitalization was 5 +/- 2 days. Conclusion. SILC is feasible. A single incision around the umbilical scar represents cosmetic progress. Comparative studies are needed to assess potential abdominal wall and recovery benefits to justify the increased cost of SILC.

Standardized algorithms for management of anastomotic leaks and related abdominal and pelvic abscesses after colorectal surgery.

BACKGROUND: The risk factors and incidence of anastomotic leak following colorectal surgery are well reported in the literature. However, the management of the multiple clinical scenarios that may be encountered has not been standardized. METHODS: The medical literature from 1973 to 2007 was reviewed using PubMed for papers relating to anastomotic leaks and abdominal abscess, with a specific emphasis on predisposing factors, prevention strategies, and treatment approaches. A six-round modified Delphi research method was utilized to find consensus among a group of expert colorectal surgeons and interventional radiologists regarding standardized management algorithms for anastomotic leaks. RESULTS: Management scenarios were divided into those for intraperitoneal anastomoses, extraperitoneal (low pelvic) anastomoses, and anastomoses with proximal diverting stomas. Management options were then based on the clinical presentation and radiographic findings and organized into three interconnected algorithms. CONCLUSIONS: This process was a useful first step toward establishing guidelines for the management of anastomotic leak.

Crohn's disease of the foregut.

Historically, Crohn's disease of the esophagus, stomach, and duodenum has been reported only rarely. With more frequent use of upper endoscopy, however, upper gastrointestinal involvement has been found to be more common than previously suspected. The surgeon with an interest in Crohn's disease needs to be familiar with all areas that are potentially affected in this perplexing and sometimes devastating disease. This article examines the literature on foregut Crohn's and discusses the incidence, clinical manifestations, diagnosis, medical management, surgical indications, and operative techniques.

Consequences of changing biodiversity.

Human alteration of the global environment has triggered the sixth major extinction event in the history of life and caused widespread changes in the global distribution of organisms. These changes in biodiversity alter ecosystem processes and change the resilience of ecosystems to environmental change. This has profound consequences for services that humans derive from ecosystems. The large ecological and societal consequences of changing biodiversity should be minimized to preserve options for future solutions to global environmental problems.

Nitrate and ammonium uptake for single-and mixed-species communities grown at elevated CO2.

Sustained increases in plant production in elevated CO2 depend on adequate belowground resources. Mechanisms for acquiring additional soil resources include increased root allocation and changes in root morphology or physiology. CO2 research to date has focused almost exclusively on changes in biomass and allocation. We examined physiological changes in nitrate and ammonium uptake in elevated CO2, hypothesizing that uptake rates would increase with the amount of available CO2. We combined our physiological estimates of nitrogen uptake with measurements of root biomass to assess whole root-system rates of nitrogen uptake. Surprisingly, physiological rates of ammonium uptake were unchanged with CO2, and rates of nitrate uptake actually decreased significantly (P<0.005). Root boomass increased 23% in elevated CO2 (P<0.005), but almost all of this increase came in fertilized replicates. Rates of root-system nitrogen uptake in elevated CO2 increased for ammonium in nutrient-rich soil (P<0.05) and were unchanged for nitrate (P>0.80). Root-system rates of nitrogen uptake were more strongly correlated with physiological uptake rates than with root biomass in unamended soil, but the reverse was true in fertilized replicates. We discuss nitrogen uptake and changes in root biomass in the context of root nutrient concentrations (which were generally unchanged with CO2) and standing pools of belowground plant nitrogen. In research to date, there appears to be a fairly general increase in root biomass with elevated CO2, and little evidence of up-regulation in root physiology.

An analytical treatment of root-to-shoot ratio and plant competition for soil nutrient and light.

By restricting biomass allocation to two compartments only-roots and leaves-we are able to treat plant resource competition analytically. We derive A*i, the optimum allocation strategy for invasion into a bare habitat, and A*f, the allocation strategy of the dominant species in an equilibrium habitat. Furthermore, we prove that in a given habitat succession proceeds from species A*i to species A*f, as long as enough intermediate species are present. Analysis of the relationship between A*i and A*f and the soil nutrient supply and disturbance rates of a habitat predicts that a dichotomy exists in succession. Low soil nutrient supply and disturbance rates favor successions from rooty to leafy species, and high soil nutrient supply and disturbance rates favor the converse. Experimental research is needed to determine whether this pattern exists in nature. Light "consumption" by plants is fundamentally different from soil nutrient consumption in our model. This difference in light and nutrient consumption makes all possible two-species equilibria unstable and leads to founder control. In our model founder control can result in arrested succession and contributes to community diversity.

Pneumatosis cystoides intestinalis in children beyond the first year of life: manifestations and management.

Beyond infancy, pneumatosis cystoides intestinalis (PCI) is rare. Data concerning pathogenesis and treatment are limited. Our experience with 12 children was examined to define predisposing factors, presentation, treatment, and outcome. Nine children were immunosuppressed, thus identifying an important etiologic subgroup. Presentation was variable but included abdominal pain, distention, diarrhea and hematochezia. Clostridium difficile was found in 3 patients and cytomegalovirus in 1. Radiographs showed free air in 3. Nine were treated with antibiotics and bowel rest, 1 with bowel rest alone, 1 with oral metronidazole, and 1 with observation. PCI resolved in 7 of 9 treated with antibiotics, although 1 child with leukemia had severe hematochezia secondary to colonic ulceration and required hemicolectomy. No other patient required laparotomy. The free air resolved in 2 of 3. There were 2 deaths, both from sepsis. One had free air on admission but no perforation was found at autopsy. Treatment recommendations remain unclear; however, C difficile and cytomegalovirus are important pathogens that should be identified and treated promptly. In symptomatic patients, bowel rest and antibiotics seem beneficial. Operative intervention should be reserved for patients with peritoneal signs, progressive deterioration, obstruction, or persistent, severe bleeding. Free air alone is not an indication for operative management in children with PCI.