Spraying deposits using different nozzles and application volumes for pest management of cotton at reproductive stage.

With the growing need for greater operational capacity, information about the effect of application volume and spray nozzles on the quality of pesticide application are essential to obtain greater efficiency in pest management in cotton crops. This study aimed to assess the effect of the spraying volume and nozzles on the deposition of spray solution on cotton crops at the reproductive stage. The treatments of the first experiment correspond to the 55, 67, 140 and 194 L ha-1 volumes obtained by variation of the displacement speed using the XR11004 flat fan nozzle. In the second assay the treatments corresponded to the applications of MGA9004 (hollow cone), XR11004 (flat fan), AIXR11004 (air induction flat fan) and CVIA04 (air induction hollow cone) nozzles with 120 L ha-1. An artificial brilliant blue food dye (FD&C 1) was used as a tracer (2.5 g L-1) to determine the deposited volumes on the leaves of the upper, middle and lower third of cotton plants. The results showed that increase in the application volume contributed to obtain the larger deposits in the upper third of the cotton crop during its reproductive phase, especially up to 140 L ha-1, but did not exhibit a significant increase of the deposition in the middle and lower thirds of the plants. The MGA9004, XR11004 and AIXR11004 nozzles provided the largest deposits in the three plant sectors. The flat fan nozzles resulted in greater uniformity of deposits in the upper and middle thirds of the plants

Precocious Metamorphosis in the Juvenile Hormone–Deficient Mutant of the Silkworm, Bombyx mori

Insect molting and metamorphosis are intricately governed by two hormones, ecdysteroids and juvenile hormones (JHs). JHs prevent precocious metamorphosis and allow the larva to undergo multiple rounds of molting until it attains the proper size for metamorphosis. In the silkworm, Bombyx mori, several “moltinism” mutations have been identified that exhibit variations in the number of larval molts; however, none of them have been characterized molecularly. Here we report the identification and characterization of the gene responsible for the dimolting (mod) mutant that undergoes precocious metamorphosis with fewer larval–larval molts. We show that the mod mutation results in complete loss of JHs in the larval hemolymph and that the mutant phenotype can be rescued by topical application of a JH analog. We performed positional cloning of mod and found a null mutation in the cytochrome P450 gene CYP15C1 in the mod allele. We also demonstrated that CYP15C1 is specifically expressed in the corpus allatum, an endocrine organ that synthesizes and secretes JHs. Furthermore, a biochemical experiment showed that CYP15C1 epoxidizes farnesoic acid to JH acid in a highly stereospecific manner. Precocious metamorphosis of mod larvae was rescued when the wild-type allele of CYP15C1 was expressed in transgenic mod larvae using the GAL4/UAS system. Our data therefore reveal that CYP15C1 is the gene responsible for the mod mutation and is essential for JH biosynthesis. Remarkably, precocious larval–pupal transition in mod larvae does not occur in the first or second instar, suggesting that authentic epoxidized JHs are not essential in very young larvae of B. mori. Our identification of a JH–deficient mutant in this model insect will lead to a greater understanding of the molecular basis of the hormonal control of development and metamorphosis

CKD-MBD after kidney transplantation

Successful kidney transplantation corrects many of the metabolic abnormalities associated with chronic kidney disease (CKD); however, skeletal and cardiovascular morbidity remain prevalent in pediatric kidney transplant recipients and current recommendations from the Kidney Disease Improving Global Outcomes (KDIGO) working group suggest that bone disease—including turnover, mineralization, volume, linear growth, and strength—as well as cardiovascular disease be evaluated in all patients with CKD. Although few studies have examined bone histology after renal transplantation, current data suggest that bone turnover and mineralization are altered in the majority of patients and that biochemical parameters are poor predictors of bone histology in this population. Dual energy X-ray absorptiometry (DXA) scanning, although widely performed, has significant limitations in the pediatric transplant population and values have not been shown to correlate with fracture risk; thus, DXA is not recommended as a tool for the assessment of bone density. Newer imaging techniques, including computed tomography (quantitative CT (QCT), peripheral QCT (pQCT), high resolution pQCT (HR-pQCT) and magnetic resonance imaging (MRI)), which provide volumetric assessments of bone density and are able to discriminate bone microarchitecture, show promise in the assessment of bone strength; however, future studies are needed to define the value of these techniques in the diagnosis and treatment of renal osteodystrophy in pediatric renal transplant recipients

Improved Approximation Bounds for the Group Steiner Problem

Given a weightedgraph and a family of k disjoint groups of nodes, the Group Steiner Problem asks for a minimum-cost routing tree that contains at least one node from each group. We give polynomial-time #-approximation algorithms for arbitrarily small values of ##0, improving on the previously known #-approximation. Our techniques also solve the graph Steiner arborescenceproblem with an O#k # approximation bound. These results are directly applicable to a practical problem in VLSI layout, namely the routing of nets with multi-port terminals. Our Java implementation is available on the Web

The cytochrome P450 gene superfamily in Drosophila melanogaster annotation intron-exon organization and phylogeny

International audienc

The moving-target traveling salesman problem

Previous literature on the Traveling Salesman Problem (TSP) assumed that the sites to be visited are stationary. Motivated by practical applications, we introduce a time-dependent generalization of TSP which we call Moving-Target TSP, where a pursuer must intercept in minimum time a set of targets which move with constant velocities. We propose approximate and exact algorithms for several natural variants of Moving-Target TSP