Are small farms more performant than larger ones in developing countries?

Meta-regressions of around 1000 cases published over the period 1997-2018 suggest that the direction of the relationship between land area and agricultural performance strongly depends on the performance indicator selected. Net value and efficiency indicators show that larger farms tend to be more performant than smallholders, while the simpler but ubiquitous gross output indicators support an inverse relationship (IR). In addition, this study also indicates a decreasing record of IR in the literature over time, regardless of the indicator used. This may be partially explained by improvements in assessment techniques but, more importantly, by agricultural structural changes. Our results invite reconsidering IR as a central assumption when formulating agricultural support in rural development policy.

Meckel's enterolith : a rare cause of mechanical small bowel subobstruction.

Meckel's diverticulum is the most common congenital gastrointestinal malformation and may present with bleeding, obstruction and diverticulitis. Symptomatic Meckel's diverticulum is associated with age <50 years, male gender, diverticular length > 2 cm and ectopic mucosa. Formation of enteroliths is a rare complication of Meckel's diverticulum and the majority of stones will remain in the diverticulum. Factors promoting enterolith formation through precipitation of calcium in the small intestinal alkaline environment include stasis as well as diverticular anatomy and histology. Mechanical obstruction due to liberation of enteroliths is even more rare and other mechanisms include intussusception, adhesions, volvulus and neoplasms. Visualization of enteroliths on plain abdominal films is challenging because not all stones are radiopaque. Surgical diverticulectomy or segmental bowel resection with anastomosis is preferred in case of complications. We present a case of mechanical small bowel sub-obstruction resulting from an expelled Meckel's enterolith.

[Study of the toxicity and results of intraperitoneal hyperthermic chemotherapy in 28 patients with peritoneal carcinomatosis]. / Etude de toxicité et résultats de la chimio-hyperthermie intra-péritonéale chez 28 patients en carcinose péritonéale.

Based on a few previous studies, intra-peritoneal hyperthermic perfusion (IPHP) with Mitomycin C could become a beneficial treatment for peritoneal carcinomatosis. Twenty eight patients with peritoneal carcinomatosis arising from intra-abdominal cancers were treated by IPHP, Mitomycin C, diluted in 3 liters of saline solution warmed to a mean temperature of 45 degrees C, was injected into the abdominal cavity for one hour. Median survival for the whole series (postoperative mortality included) was 260 days. For patients with incomplete resection, median survival was 104 days. For patients with complete resection of carcinomatous nodules larger than 3 mm (19 patients), it was 450 days. In this group, actuarial survival was 56% at 1 year and 42% at 2 years. Only 5 (18%) of the 28 patients developed ascitic effusion during follow-up. These results confirm the efficacity of IPHP on ascitic effusion and on survival rate in patients with nearly complete resection of peritoneal carcinomatosis.

Viability of long-term cryopreserved human saphenous veins.

The feasibility of maintaining long-term viability of human venous allografts by cryopreservation has been investigated. Segments of vein were obtained from 85 patients undergoing a stripping operation for varicose veins. The venous segments were immersed in a dimethylsulfoxide 15% solution, deep frozen at -196 degrees C in liquid nitrogen and preserved for a duration of 1 week to 24 months. Light microscopy (n = 126) failed to demonstrate striking differences between control veins and any of the cryopreserved veins. The types of damage observed at scanning electron microscopy included endothelial cell separation, endothelial cell loss, exposed basement membrane and exposed fibrillar collagen, which were graded on a scale. The score for short term (less than 3 weeks) stored veins was 8.1 +/- 0.9 (mean +/- SEM) and did not differ from the long-term (greater than 10 weeks) stored veins score (6.3 +/- 1.0, p NS). The tissue enzymes LDH, GOT, GPT, CPK were measured in the frozen vein groups (n = 115) after thawing to room temperature. Cryopreservation did not alter any of the tissue enzymes measured when compared to controls. Endothelial fibrinolytic activity (FA) of 58 venous segments cryopreserved for a mean duration of 20 months was 6136.4 +/- 292.1 Tissue Activator Units (TAU) and did not differ from FA of 11 controls (5989.1 +/- 696.8 TAU). Synthesis of 6-Keto-PGF1-alpha-2, a stable breakdown product of PGI2, measured in 10 venous segments cryopreserved for 10 months, was significantly higher than in 13 veins stored in saline for 12 hours at 4 degrees C (2.8 +/- 0.4 vs 0.4 +/- 0.1 PG ml-1mg-1min-1, respectively; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)