Agronomic, economic and ecological aspects of the papaya (Carica papaya) production in Tabasco, Mexico

The cultivation of papaya is important in the tropic because it provides source of income to the farmer within a short time. Statistical data were obtained from farmers located in the Chontalpa, Rios and Centro-Sierra regions; the size of the survey was 67 farmers. The study shows the results of the farmers’ problem in a drastic reduction of their productivity because of the virosis and low prices in commercialization. The farmers were classified into three levels of technology, “low”, “middle” and “high”. The first one covers 88% of the farmers in seasonal conditions in contrast with the high technology that concentrates 4.5% in irrigation conditions. According to the technology used, the fertilizer shows more yields. Economically, the high technology had an internal tax return of 0.43 in comparison with the low technology of 0.25, which means that the investment is recovered with different yields. However, the use of high technology makes the system more competitive. Key words

The effects of spinal cord injury on bone loss and dysregulation of the calcium/parathyroid hormone loop in mice

AbstractObjectiveTo map the progression of osteoporosis following spinal cord injury in mice in specific areas and analyze changes in parathyroid hormone (PTH) and ion levels which could be responsible for overall bone loss.Summary of background dataSpinal cord injury rapidly induces severe bone loss compared to other conditions, yet the cause of this bone loss has not been identified. Studies suggest the bone loss after injury is not solely due to disuse.MethodsTo quantify bone loss we weighed individual bones and measured bone mineral density using dual energy X-ray absorptiometry at acute (1 week) and chronic (4 week) time points following a T9 contusion. An ELISA was used to measure blood PTH levels at 1 and 4 weeks after injury. Calcium and phosphate levels were also analyzed at 4 weeks following injury at the University of Miami pathology core.ResultsWe observed a significant decrease in bone mineral density in hind limbs after an acute injury, and found this bone loss to progress over time. Furthermore, following chronic injury a decrease in bone mineral density is also observed in bones above the level of injury and in the total bone mineral density. We observed a significant decrease in parathyroid hormone levels in injured mice at the chronic time point, but not at the acute time point which suggests this could be involved in the global bone loss following injury. We also observed a significant increase in serum calcium levels following injury which could account for the imbalance of PTH levels

Enfermedades del frijol

Diseases are one of the limiting factors to bean production in L.A. The prevalency and severity of the disease depends on the quantity of inoculum existing in the region, environmental conditions and the quality of the seed used. Data are given on geographic distribution, favorable climatic conditions for development, symptomatology, vectors, type of damage caused and control measures, including var. resistant to (1) fungal diseases, the most numerous and causing the most damage: rust, anthracnose, angular leaf spot, root rot, web blight, gray spot, powdery mildew; (2) virus diseases, some of economic importance transmitted by aphids (BCMV, BYMV); transmitted by whiteflies (BGMV, bean chlorotic mottle, euphorbia mosaic); transmitted by chrysomelids (BRMV, pod mottle, BSMV, yellow mottle); (3) bacterial diseases are few but can be a serious limitation to the crop: common and fuscous blights, halo blight; and (4) nematodes: Meloidogyne sp., Trichodorus spp., Pratylenchus spp., Heterodera spp. (CIAT