Adoption of Variable Rate Technology

Site Specific Management (SSM), which also variously referred to as Variable Rate Technology (VRT), is an emergingtechnology that enables producers to make more precise input application decisions based on soil and fieldcharacteristics. This study analyzes factors influencing the adoption of VRT for fertilizer application for cash grainproduction in Ohio. Results show that producer and field characteristics might influence the adoption decision onvarious SSM components differently. It also provides insight as to the sequence of adoption of SSM componenttechnologies and how this sequence might differ for producers of differing characteristics

An Economic Analysis of Variable Rate Technology

Variable Rate Technology (VRT) offers an opportunity to improve production efficiency by allowing input applicationsto fluctuate in response to spatial variations in soil characteristics and nutrient levels. Society may also benefit fromreduced negative externalities, such as surface and groundwater contamination, from input applications. Using adynamic spatial model, this study examines how the interaction among variability, spatial autocorrelation, and meanlevel of soil fertility affects optimal sampling density and the economic gains from VRT. VRT was found to beprofitable under selected conditions, and the optimal grid size will vary with these conditions. In the case wherevariability and mean fertility levels are significantly high associated with low spatial autocorrelation, VRT producesgreater net returns than Uniform Rate Technology (URT), even with the smallest grid size to base the input applicationdecisions. Results also demonstrate that optimal grid size increases with increased spatial autocorrelation

Continuous mapping identifies Loci associated with weevil resistance [Cosmopolites sordidus (Germar)] in a triploid banana population

Open Access Journal; Published online: 29 Nov 2021The first step towards marker-assisted selection is linking the phenotypes to molecular markers through quantitative trait loci (QTL) analysis. While the process is straightforward with self-pollinating diploid species, QTL analysis in polyploids requires unconventional methods. In this study, we have identified markers associated with weevil Cosmopolites sordidus (Germar) resistance in banana using 138 triploid (2n = 3x) hybrids derived from a cross between a tetraploid ‘Monyet’ (2n = 4x) and a diploid ‘Kokopo’ (2n = 2x) banana genotypes. The population was genotyped by DArTSeq, resulting in 18,009 polymorphic SNPs between the two parents. Marker–trait association was carried out by continuous mapping where the adjusted trait means for corm peripheral damage (PD) and total cross-section damage (TXD), both on the logit scale, were regressed on the marker allele frequencies. Forty-four SNPs were identified that were associated with corm peripheral damage on the chromosomes 5, 6 and 8 with 41 of them located on chromosome 6 and segregating in ‘Kokopo’. Eleven SNPs associated with corm total cross-section damage were identified on chromosome 6 and segregating in ‘Monyet’. The additive effect of replacing one reference allele with the alternative allele was determined at each marker position. The peripheral damage QTL was confirmed using conventional QTL linkage analysis in the simplex markers segregating in ‘Kokopo’ (AAAA × RA). We also identified 43 putative genes in the vicinity of the markers significantly associated with the two traits. The identified loci associated with resistance to weevil damage will be used in the efforts of developing molecular tools for marker-assisted breeding in banana

Groundwater resources assessment using integrated geophysical techniques in the southwestern region of Peninsular Malaysia.

Combined geophysical techniques such as multi-electrode resistivity, induced polarization, and borehole geophysical techniques were carried out on volcano-sedimentary rocks in the north of Gemas as part of the groundwater resource’s investigations. The result identifies four resistivity units: the tuffaceous mudstone, tuffaceous sandstone, the tuff bed, and the shale layer. Two types of aquifer systems in terms of storage were identified within the area: one within a fracture system (tuff), which is the leaky area through which vertical flow of groundwater occurs, and an intergranular property of the sandy material of the aquifer which includes sandstone and tuffaceous sandstone. The result also reveals that the aquifer occupies a surface area of about 3,250,555 m2 with a mean depth of 43.71 m and a net volume of 9.798 × 107 m3. From the approximate volume of the porous zone (28 %) and the total aquifer volume, a usable capacity of (274.339 ± 30.177) × 107 m3 of water in the study area can be deduced. This study provides useful information that can be used to develop a much broader understanding of the nature of groundwater potential in the area and their relationship with the local geology

General anaesthetic and airway management practice for obstetric surgery in England: a prospective, multicentre observational study

There are no current descriptions of general anaesthesia characteristics for obstetric surgery, despite recent changes to patient baseline characteristics and airway management guidelines. This analysis of data from the direct reporting of awareness in maternity patients’ (DREAMY) study of accidental awareness during obstetric anaesthesia aimed to describe practice for obstetric general anaesthesia in England and compare with earlier surveys and best-practice recommendations. Consenting patients who received general anaesthesia for obstetric surgery in 72 hospitals from May 2017 to August 2018 were included. Baseline characteristics, airway management, anaesthetic techniques and major complications were collected. Descriptive analysis, binary logistic regression modelling and comparisons with earlier data were conducted. Data were collected from 3117 procedures, including 2554 (81.9%) caesarean deliveries. Thiopental was the induction drug in 1649 (52.9%) patients, compared with propofol in 1419 (45.5%). Suxamethonium was the neuromuscular blocking drug for tracheal intubation in 2631 (86.1%), compared with rocuronium in 367 (11.8%). Difficult tracheal intubation was reported in 1 in 19 (95%CI 1 in 16–22) and failed intubation in 1 in 312 (95%CI 1 in 169–667). Obese patients were over-represented compared with national baselines and associated with difficult, but not failed intubation. There was more evidence of change in practice for induction drugs (increased use of propofol) than neuromuscular blocking drugs (suxamethonium remains the most popular). There was evidence of improvement in practice, with increased monitoring and reversal of neuromuscular blockade (although this remains suboptimal). Despite a high risk of difficult intubation in this population, videolaryngoscopy was rarely used (1.9%)

Inferring HIV-1 transmission networks and sources of epidemic spread in Africa with deep-sequence phylogenetic analysis

To prevent new infections with human immunodeficiency virus type 1 (HIV-1) in sub-Saharan Africa, UNAIDS recommends targeting interventions to populations that are at high risk of acquiring and passing on the virus. Yet it is often unclear who and where these ‘source’ populations are. Here we demonstrate how viral deep-sequencing can be used to reconstruct HIV-1 transmission networks and to infer the direction of transmission in these networks. We are able to deep-sequence virus from a large population-based sample of infected individuals in Rakai District, Uganda, reconstruct partial transmission networks, and infer the direction of transmission within them at an estimated error rate of 16.3% [8.8–28.3%]. With this error rate, deep-sequence phylogenetics cannot be used against individuals in legal contexts, but is sufficiently low for population-level inferences into the sources of epidemic spread. The technique presents new opportunities for characterizing source populations and for targeting of HIV-1 prevention interventions in Africa

General anaesthetic and airway management practice for obstetric surgery in England: a prospective, multi-centre observational study

There are no current descriptions of general anaesthesia characteristics for obstetric surgery, despite recent changes to patient baseline characteristics and airway management guidelines. This analysis of data from the direct reporting of awareness in maternity patients' (DREAMY) study of accidental awareness during obstetric anaesthesia aimed to describe practice for obstetric general anaesthesia in England and compare with earlier surveys and best-practice recommendations. Consenting patients who received general anaesthesia for obstetric surgery in 72 hospitals from May 2017 to August 2018 were included. Baseline characteristics, airway management, anaesthetic techniques and major complications were collected. Descriptive analysis, binary logistic regression modelling and comparisons with earlier data were conducted. Data were collected from 3117 procedures, including 2554 (81.9%) caesarean deliveries. Thiopental was the induction drug in 1649 (52.9%) patients, compared with propofol in 1419 (45.5%). Suxamethonium was the neuromuscular blocking drug for tracheal intubation in 2631 (86.1%), compared with rocuronium in 367 (11.8%). Difficult tracheal intubation was reported in 1 in 19 (95%CI 1 in 16-22) and failed intubation in 1 in 312 (95%CI 1 in 169-667). Obese patients were over-represented compared with national baselines and associated with difficult, but not failed intubation. There was more evidence of change in practice for induction drugs (increased use of propofol) than neuromuscular blocking drugs (suxamethonium remains the most popular). There was evidence of improvement in practice, with increased monitoring and reversal of neuromuscular blockade (although this remains suboptimal). Despite a high risk of difficult intubation in this population, videolaryngoscopy was rarely used (1.9%)