Crop photoperiodism model 2.0 for the flowering time of sorghum and rice that includes daily changes in sunrise and sunset times and temperature acclimation

BACKGROUND AND AIMS

Daylength determines flowering dates. However, questions remain regarding flowering dates in the natural environment, such as the synchronous flowering of plants sown simultaneously at highly contrasting latitudes. The daily change in sunrise and sunset times is the cue for the flowering of trees and for the synchronization of moulting in birds at the equator. Sunrise and sunset also synchronize the cell circadian clock, which is involved in the regulation of flowering. The goal of this study was to update the photoperiodism model with knowledge acquired since its conception.

METHODS

A large dataset was gathered, including four 2-year series of monthly sowings of 28 sorghum varieties in Mali and two 1-year series of monthly sowings of eight rice varieties in the Philippines to compare with previously published monthly sowings in Japan and Malaysia, and data from sorghum breeders in France, Nicaragua and Colombia. An additive linear model of the duration in days to panicle initiation (PI) and flowering time using daylength and daily changes in sunrise and sunset times was implemented.

KEY RESULTS

Simultaneous with the phyllochron, the duration to PI of field crops acclimated to the mean temperature at seedling emergence within the usual range of mean cropping temperatures. A unique additive linear model combining daylength and daily changes in sunrise and sunset hours was accurately fitted for any type of response in the duration to PI to the sowing date without any temperature input. Once calibrated on a complete and an incomplete monthly sowing series at two tropical latitudes, the model accurately predicted the duration to PI of the concerned varieties from the equatorial to the temperate zone.

CONCLUSIONS

Including the daily changes in sunrise and sunset times in the updated photoperiodism model largely improved its accuracy at the latitude of each experiment. More research is needed to ascertain its multi-latitudinal accuracy, especially at latitudes close to the equator.

[Efficacy and tolerance of Latanoprost given as a first intention in the treatment of primitive open angle glaucoma in African melanoderm]

OBJECTIVE

To assess the reduction in IOP and ocular symptoms in patients newly diagnosed with POAG and treated with latanoprost as monotherapy.

PATIENTS AND METHOD

A multicentric, cross-sectional, descriptive study was conducted. We included adults newly diagnosed with POAG. All patients received one drop of preserved latanoprost 0.005% in each eye every night for 12 weeks. Changes in IOP and ophthalmic signs and symptoms were assessed during and at the end of treatment.

RESULTS

A total of 524 patients were included, with a participation rate of 93% at 12 weeks. The mean age was 52.79±17.33 years, and the sex ratio M/F was 1.39. At inclusion, the mean IOP was 21.68±9.72mmHg. After 2 weeks of treatment, the mean IOP was 15.49±5.81mmHg, for a reduction of 28.55%. After 12 weeks of treatment, the mean IOP was 13.16±3.54mmHg, for a reduction of 39.30%. The main symptom recorded was a gritty foreign body sensation, the frequency of which was 4.72% at W2 and 2.45% at W12. The main sign was hyperemia (4.33% at W2 and 1.84% at W12).

CONCLUSION

Latanoprost given as first-line monotherapy in POAG in blacks considerably reduces IOP. The incidence of side effects remains low; it is higher at the start of treatment.

[Contribution of mode B ultrasound in the diagnostic and therapeutic management of ocular pathologies in Abidjan]

BACKGROUND

Ocular pathology is common throughout the world. The aim of our work was to study the contribution of mode B ultrasound in the diagnostic and therapeutic management of ocular pathologies in Abidjan.

MATERIALS AND METHODS

Prospective, descriptive study, carried out at the Abidjan Military Hospital during a period of 3 months. Eye examinations were performed exclusively with a mode B ultrasound scanner by senior radiologists. All patients who performed an ocular ultrasound were included in the study. The epidemioclinical data, the examination request and the ultrasound results were analysed.

RESULTS

We identified 114 cases of ocular ultrasound, i.e. 17% of the ultrasounds performed. The median age was 39.2 years with a male/female sex ratio of 1.15. Decreased visual acuity was the main indication Preoperative assessment for cataract (32.5%) was the most frequent indication. Ultrasound was pathological in almost all cases (98.2%). The most frequent pathology was cataract (77.2%) with predominance of total lens opacifications (45.6%). Other pathologies found were retinal detachment (21.1%) and intraocular hemorrhage (17%).

CONCLUSION

The ocular pathology was varied in our context. It predominated in subjects of variable age and more often in males. Ocular ultrasonography in B mode was indicated for diagnostic purposes to explore trauma and visual acuity impairment, but especially for therapeutic purposes to establish. the preoperative assessment of the lesions observed. Its diagnostic sensitivity was 98.1%.

Characteristics of Peri-urban Dairy Herds of Bobo-Dioulasso (Burkina Faso)

Peri-urban dairy cattle farms within 50 km of Bobo-Dioulasso were studied to assess herd type, disease incidence, management, feeding and breeding strategy. Out of 417 cattle farmers, 42% had dairy objectives and were studied. Among these peri-urban dairy farmers, 60% were settled, 36% semi-settled, and 4% transhumant. In total, they held 4558 dairy cows, of which 32% lactated during the study. The prevalence of mastitis (55%) increased (p<0.05) with herd size. Advanced strategies for supplementary feeding and breeding were most frequent in small herds (<30 cattle). None of the large herds (>60 cattle) had advanced breeding strategies. Bulls and cows were culled at younger ages in herds with better breeding strategy. Overall, this resulted in higher individual milk offtake in small herds (2.46 L/day) compared with large herds (1.25 L/day). Pure breeds were rarely used, and the presence of Bos taurus baoulé naturally selected for trypanotolerance was low. The prevalence of trypanosomosis (40%) in herds dominated by Bos indicus zebu and Méré (Zebu x Baoulé) is an argument for maintenance of biodiversity and selection of Baoulé for milk production.

[Maternal mortality. Apropos of 212 instances in 7 years (1980-1986) at the Ignace-Deen Maternity Hospital in Conakry (Guinea)]

In Conakry the maternal mortality rate in the University Hospital is not the real maternal mortality rate of the country but it gives an idea of the importance of this problem of public health. The authors try to explain the reasons for this high mortality and propose preventive measures: increase in primary health care, equipping of regional obstetric wards in referral hospitals, training of personnel, health education of the population.