Développement d'un système d'analyse d'images pour des tests en laboratoire de machines de semis

International audienceAim of this research is to develop an experimental apparatus to measure distances between seeds for precision sowing machines and to count number of seeds in a determined area for bulk drillers on a conveyor band by using image analyses techniques. System consists of a conveyor band, two cameras, a light, a computer, which includes an image acquisition board, an input board and a software to realise the desired measures using some image processing algorithms. Wheat, sunf lower, onion, and sugar beet seeds were used in this research. The results showed that there is no statistically significant differences between measurement of the image analyses system and human

Possibilities of direct drilling and reduced tillage in second crop silage corn

Reduced tillage techniques and direct seeding method that can replace the conventional methods, were examined in the western part of Turkey (Trakya Region) during the years of 1999 and 2000. In the experiment five tillage methods and no-tillage (DRD) were used. All tillage methods and direct seeding were applied in the dry soil conditions except conventional method. The tillage methods are heavy-duty disc harrow (DIS), plough (PLO), rotary tiller (ROT), tillage combination of tine, rotor and roller (TIC) and conventional tillage method in which plough is used in wet soil condition. The effects of the treatments on soil penetration resistance, mean emergence dates, percentage of emerged seedlings, plant height, stem diameter and silage corn yield were measured. All the parameters tested were found to be statistically significant. Direct seeding method gave the best result for mean of emergence dates (4.93 days) and percentage of emerged seedlings (95.48%). The best result for silage yield (69.32 Mg ha-1) was found in tillage combination. The lowest yield (58.92 Mg ha-1) was found in the heavy-duty disc harrow tillage method. Direct seeding gives the best results for tillage efficiency parameters, such as fuel consumption, effective power requirement and field efficiency. Reduced tillage and direct seeding methods can be used in second crop silage corn in the region. © 2005 Elsevier B.V. All rights reserved

A single-cell atlas of de novo β-cell regeneration reveals the contribution of hybrid β/δ cells to diabetes recovery in zebrafish

Regeneration-competent species possess the ability to reverse the progression of severe diseases by restoring the function of the damaged tissue. However, the cellular dynamics underlying this capability remain unexplored. Here, we use single-cell transcriptomics to map the cellular dynamics underlying de novo β-cell regeneration during induction and recovery from diabetes in zebrafish. We show that the zebrafish has evolved two distinct types of somatostatin-producing δ-cells, which we term δ1- and δ2-cells. Moreover, we characterize a small population of glucose-responsive islet cells, which share the hormones and fate-determinants of both β- and δ1-cells. The transcriptomic analysis of β-cell regeneration reveals that the development of β/δ hybrid cells constitutes a prominent source of insulin-expression during diabetes recovery. Using in vivo calcium imaging and cell tracking, we further show that the hybrid cells form de novo upon β-cell loss and acquire glucose-responsiveness in the course of regeneration. The overexpression of dkk3, a gene enriched in hybrid cells, increases their formation in the absence of β-cell injury. Our data provide an atlas of β-cell regeneration and indicate that the rapid formation of glucose-responsive hybrid cells contributes to the resolution of diabetes in zebrafish