Application of Polyacrylamide (PAM) through Lay-Flat Polyethylene Tubing: Effects on Infiltration, Erosion, N and P Transport, and Corn Yield.

Polyacrylamides (PAMs), when applied as a soil amendment, purportedly improve soil infiltration, decrease erosion, and reduce offsite agrochemical transport. The effect of PAM on infiltration, erosion, agrochemical transport, and crop yield when applied in furrow to mid-southern US production systems has not been evaluated. The objective of this study was to assess PAM effects on infiltration, erosion, corn ( L.) grain yield, and nitrogen (N) and phosphorus (P) transport when applied at 10 mg L through lay-flat polyethylene tubing. A 2-yr field study was conducted at the Mississippi State Delta Research and Extension Center in Stoneville, MS, on a Dundee silt loam and a Forestdale silty clay loam. The experimental design was a randomized complete block with four replications of each treatment: irrigated plus no PAM (control) and irrigated plus PAM at 10 mg L. Each irrigation event delivered 102 mm of water at 18.9 L m per furrow, and runoff was captured in a holding tank on the lower end of each plot. Pooled over year and soil texture, PAM increased infiltration and corn grain yield by 6% ( ≤ 0.0398). Polyacrylamide effects on the offsite transport of sediment and N and P were inconsistent, varying across year and soil texture. Results indicate that PAM improves infiltration and corn grain yield on silt loam and silty clay loam textured soils; however, further research is required before PAM can be recommended as a best management practice for mitigating erosion and offsite agrochemical transport in mid-southern production systems.

The Impact of Simulated Corn Earworm (Lepidoptera: Noctuidae) Damage in Indeterminate Soybean.

Field experiments were conducted in Starkville and Stoneville, MS, during 2012 and 2013 to evaluate fruit removal level and timing on soybean growth, crop maturity, and yield. Fruit removal treatments consisted of 0, 50, and 100% of all fruit removed at specified growth stages (R2, R3, R4, and R5.5). Plant heights were determined at least biweekly from the time damage was imposed until R7. The impact of fruit removal level and timing on crop maturity was determined by estimating the percentage of naturally abscised leaves at 137 days after planting (DAP) when control plots were ∼10-15 d from harvest and the percentage of nonsenesced main stems at 139 DAP. There was no significant impact of fruit removal timing or fruit removal level on plant height or canopy width. Significant delays in crop maturity were observed when fruit removal was imposed at the R5.5 growth stage. Significant reductions in yield and crop value were observed as early as R3 and R4 when 100% of fruit was removed. Both fruit removal levels at R5.5 resulted in a significant reduction in yield and crop value compared with the nontreated control. Indeterminate soybeans appear to have the ability to compensate for some fruit loss during the early to middle reproductive growth stages without delaying maturity. However, severe fruit loss causes increasingly more yield loss as the plant approached maturity. Thresholds and economic injury levels therefore need to be adjusted accordingly to account for the dynamic nature of yield losses and crop maturity delays.

New constraint on the existence of the µ+ → e+ γ decay.

The analysis of a combined data set, totaling 3.6 × 10(14) stopped muons on target, in the search for the lepton flavor violating decay µ(+) → e(+)γ is presented. The data collected by the MEG experiment at the Paul Scherrer Institut show no excess of events compared to background expectations and yield a new upper limit on the branching ratio of this decay of 5.7 × 10(-13) (90% confidence level). This represents a four times more stringent limit than the previous world best limit set by MEG.

New limit on the lepton-flavor-violating decay µ+→e+γ.

We present a new result based on an analysis of the data collected by the MEG detector at the Paul Scherrer Institut in 2009 and 2010, in search of the lepton-flavor-violating decay µ(+)e(+)γ. The likelihood analysis of the combined data sample, which corresponds to a total of 1.8×10(14) muon decays, gives a 90% C.L. upper limit of 2.4×10(-12) on the branching ratio of the µ(+)→e(+)γ decay, constituting the most stringent limit on the existence of this decay to date.

Hot topic: performance of bovine high-density genotyping platforms in Holsteins and Jerseys.

Two high-density single nucleotide polymorphism (SNP) genotyping arrays have recently become available for bovine genomic analyses, the Illumina High-Density Bovine BeadChip Array (777,962 SNP) and the Affymetrix Axiom Genome-Wide BOS 1 Array (648,874 SNP). These products each have unique design and chemistry attributes, and the extent of marker overlap and their potential utility for quantitative trait loci fine mapping, detection of copy number variation, and multibreed genomic selection are of significant interest to the cattle community. This is the first study to compare the performance of these 2 arrays. Deoxyribonucleic acid samples from 16 dairy cattle (10 Holstein, 6 Jersey) were used for the comparison. An independent set of DNA samples taken from 46 Jersey cattle and 18 Holstein cattle were used to ascertain the amount of SNP variation accounted by the 16 experimental samples. Data were analyzed with SVS7 software (Golden Helix Inc., Bozeman, MT) to remove SNP having a call rate less than 90%, and linkage disequilibrium pruning was used to remove linked SNP (r² ≥ 0.9). Maximum, average, and median gaps were calculated for each analysis based on genomic position of SNP on the bovine UMD3.1 genome assembly. All samples were successfully genotyped (≥ 98% SNP genotyped) with both platforms. The average number of genotyped SNP in the Illumina platform was 775,681 and 637,249 for the Affymetrix platform. Based on genomic position, a total of 107,896 SNP were shared between the 2 platforms; however, based on genotype concordance, only 96,031 SNP had complete concordance at these loci. Both Affymetrix BOS 1 and Illumina BovineHD genotyping platforms are well designed and provide high-quality genotypes and similar coverage of informative SNP. Despite fewer total SNP on BOS 1, 19% more SNP remained after linkage disequilibrium pruning, resulting in a smaller gap size (5.2 vs. 6.9 kb) in Holstein and Jersey samples relative to BovineHD. However, only 224,115 Illumina and 241,038 Affymetrix SNP remained following removal of SNP with a minor allele frequency of zero in Holstein and Jersey samples, resulting in an average gap size of 11,887 bp and 11,018 bp, respectively. Combining the 354,348 informative (r² ≥ 0.9), polymorphic (minor allele frequency ≥ 0), unique SNP data from both platforms decreased the average gap size to 7,560 bp. Genome-wide copy number variant analyses were performed using intensity files from both platforms. The BovineHD platform provided an advantage to the copy number variant data compared with the BOS 1 because of the larger number of SNP, higher intensity signals, and lower background effects. The combined use of both platforms significantly improved coverage over either platform alone and decreased the gap size between SNP, providing a valuable tool for fine mapping quantitative trait loci and multibreed animal evaluation.

Influence of Soil Moisture Zones on Rice Water Weevil (Coleoptera: Curculionidae) Populations in Furrow Irrigated Rice.

Water conservation is an important factor for production of rice in the United States because of declining aquifer levels, but little research has been done to evaluate insect management in rice systems integrating water conservation practices. Rice water weevil, Lissorhoptrus oryzophilus Kuschel, is an important insect pest of rice in the U.S. Rice water weevil is a semiaquatic species that relies on flooded conditions to complete larval development, so water conservation practices are likely to impact their pest status. The study was conducted across the Mississippi River alluvial floodplain to compare rice water weevil population densities in different zones of a furrow irrigated rice field to a conventionally flooded rice field. All locations were sampled at 3, 4, and 5 wk after the initial irrigation. Larval densities were greatest in the lower end of furrow irrigated fields and in the adjacent flooded rice field compared with the upper and middle sections that did not hold standing water when averaged across three sample dates. Also, rice water weevil densities were greater during week five than week three. In terms of rice yields, the top third of furrow irrigated rice fields, the section that remained mostly dry, produced lower rough rice yields than all other sections and the flooded field. These results suggest that rice water weevil populations can be lower in a furrow irrigated rice system. As a result, more research is needed to determine whether a spatial management plan can be developed based on soil moisture zones in furrow irrigated rice.

Assessment of inbreeding depression in a Guzerat dairy herd: effects of individual increase in inbreeding coefficients on production and reproduction.

Influences of inbreeding on daily milk yield (DMY), age at first calving (AFC), and calving intervals (CI) were determined on a highly inbred zebu dairy subpopulation of the Guzerat breed. Variance components were estimated using animal models in single-trait analyses. Two approaches were employed to estimate inbreeding depression: using individual increase in inbreeding coefficients or using inbreeding coefficients as possible covariates included in the statistical models. The pedigree file included 9,915 animals, of which 9,055 were inbred, with an average inbreeding coefficient of 15.2%. The maximum inbreeding coefficient observed was 49.45%, and the average inbreeding for the females still in the herd during the analysis was 26.42%. Heritability estimates were 0.27 for DMY and 0.38 for AFC. The genetic variance ratio estimated with the random regression model for CI ranged around 0.10. Increased inbreeding caused poorer performance in DMY, AFC, and CI. However, some of the cows with the highest milk yield were among the highly inbred animals in this subpopulation. Individual increase in inbreeding used as a covariate in the statistical models accounted for inbreeding depression while avoiding overestimation that may result when fitting inbreeding coefficients.

Evaluation of Flood Removal in Combination with Insecticide Seed Treatment for Rice Water Weevil (Coleoptera: Curculionidae) Larval Management in Rice.

An experiment was conducted at the Delta Research and Extension Center in Stoneville, MS during 2017 and 2018 to determine whether removal of the flood is an economical method of control for rice water weevil, Lissorhoptrus oryzophilus Kuschel. This experiment compared a continuous flood production system to draining a rice field completely and reestablishing a flood for the remainder of the growing season. In addition, two insecticide seed treatments, thiamethoxam and chlorantraniliprole, were compared with an untreated control within each system. Rice water weevil densities were measured prior to draining at 3 wk after flood and again after the flood was reestablished in drained plots. Rice water weevil densities were greater in 2017 than 2018. Chlorantraniliprole at the predrainage and postdrainage sample timing reduced larval numbers compared with the untreated control. The plots where water was removed until soil cracking then re-flooded had significantly lower weevil populations than plots that were continuously flooded during 2018 only. Draining of plots resulted in lower yields in 2018, but not in 2017. Additionally, both of the insecticide seed treatments resulted in greater yields and economic returns than the untreated control. Draining of flooded rice when rice water weevil larvae were present did not provide a consistent benefit, and may result in yield and economic penalties. Insecticide seed treatments consistently provided greater yield benefits in flooded rice. Based on these results, draining of flooded rice is not recommended to manage rice water weevil and insecticide seed treatments should be used to minimize economic losses.

A preorganized active site in the crystal structure of the Tetrahymena ribozyme.

Group I introns possess a single active site that catalyzes the two sequential reactions of self-splicing. An RNA comprising the two domains of the Tetrahymena thermophila group I intron catalytic core retains activity, and the 5.0 angstrom crystal structure of this 247-nucleotide ribozyme is now described. Close packing of the two domains forms a shallow cleft capable of binding the short helix that contains the 5' splice site. The helix that provides the binding site for the guanosine substrate deviates significantly from A-form geometry, providing a tight binding pocket. The binding pockets for both the 5' splice site helix and guanosine are formed and oriented in the absence of these substrates. Thus, this large ribozyme is largely preorganized for catalysis, much like a globular protein enzyme.

Crystal structure of a group I ribozyme domain: principles of RNA packing.

Group I self-splicing introns catalyze their own excision from precursor RNAs by way of a two-step transesterification reaction. The catalytic core of these ribozymes is formed by two structural domains. The 2.8-angstrom crystal structure of one of these, the P4-P6 domain of the Tetrahymena thermophila intron, is described. In the 160-nucleotide domain, a sharp bend allows stacked helices of the conserved core to pack alongside helices of an adjacent region. Two specific long-range interactions clamp the two halves of the domain together: a two-Mg2+-coordinated adenosine-rich corkscrew plugs into the minor groove of a helix, and a GAAA hairpin loop binds to a conserved 11-nucleotide internal loop. Metal- and ribose-mediated backbone contacts further stabilize the close side-by-side helical packing. The structure indicates the extent of RNA packing required for the function of large ribozymes, the spliceosome, and the ribosome.

RNA tertiary structure mediation by adenosine platforms.

The crystal structure of a group I intron domain reveals an unexpected motif that mediates both intra- and intermolecular interactions. At three separate locations in the 160-nucleotide domain, adjacent adenosines in the sequence lie side-by-side and form a pseudo-base pair within a helix. This adenosine platform opens the minor groove for base stacking or base pairing with nucleotides from a noncontiguous RNA strand. The platform motif has a distinctive chemical modification signature that may enable its detection in other structured RNAs. The ability of this motif to facilitate higher order folding provides one explanation for the abundance of adenosine residues in internal loops of many RNAs.

The utility of publicly reported cancer treatment wait time information for patients and health care providers.

AIMS: To determine the utility of web-based radiation wait time information for patients and health care providers in decision-making. To revise the information using a simulated laboratory environment and to re-evaluate the new web-based information. MATERIALS AND METHODS: An online 'pop-up' survey on the Cancer Care Ontario (CCO) website measured user satisfaction. Qualitative data were gathered through patient focus groups and physician interviews. On the basis of the analysis, the website was revised and usability testing conducted. The information was re-evaluated by end-users through survey methodology. RESULTS: The majority accessing the wait time website were patients and family members. The modal age of use of the website was 31-50 years. Patients found the information more helpful after redesign than health professionals, but both found the language less easy to understand, highlighting the need to continuously evaluate the effectiveness of the website. Patients did not identify themselves as consumers of wait time information. Their expectation was that physicians would determine the urgency for treatment and would ensure timely access to care. Physicians reported that they did not use the CCO website on wait times and would not use the data for decision-making. Referrals were based on urgency of care and usual referral patterns. Referral patterns did not shift to centres with shorter wait times. CONCLUSIONS: The results of this study did not confirm the usefulness of the web-based wait time information for patients and physicians as a resource on how to obtain timely access to radiation treatment. Patients relied on their physician to manage their access to treatment according to the urgency of their clinical condition. Physicians preferred their established referral process rather than referring their patients to centres with shorter wait times. As patients become more computer savvy, it will be interesting to see if they increasingly become consumers of web-based wait time information.

Genetic parameters for carcass and ultrasound traits in Hereford and admixed Simmental beef cattle: Accuracy of evaluating carcass traits.

Genetic parameters are required to evaluate carcass merit using correlated real-time ultrasound (RTU) measurements. Many registered bulls and heifers are measured using RTU before consideration for selection as parents, whereas few animals are recorded for carcass traits and those are often crossbred steers. The objective of this study was to estimate genetic parameters required for evaluating carcass merit in the American Hereford Association (AHA) and the American Simmental Association (ASA) using multivariate models and to assess accuracy of carcass trait estimated breeding values (EBV) for selection candidates. All available carcass data including carcass weight (CWT), fat thickness (FAT), longissimus muscle area (LMA), and marbling score (MRB) were provided by the AHA and the ASA along with RTU data including fat thickness (UFAT), longissimus muscle area (ULMA), and percentage of intramuscular fat (UIMF). Carcass data comprised 6,054 AHA and 9,056 ASA cattle, while RTU data in comparable numbers from close relatives comprised 6,074 AHA and 7,753 ASA cattle. Pedigrees included 33,226 AHA and 37,665 ASA animals. Fixed effects for carcass and RTU data included contemporary group, age at scan/slaughter, and major breed percentages. Restricted maximum likelihood procedures were applied to all the carcass and RTU measurements, along with birth weight to account for selection, fitting 8-trait multivariate models separately for each breed association. Heritability estimates for AHA and ASA carcass traits were 0.41 ± 0.04 and 0.25 ± 0.03 for FAT, 0.47 ± 0.04 and 0.32 ± 0.03 for LMA, 0.48 ± 0.04 and 0.43 ± 0.04 for MRB, 0.51 ± 0.04 and 0.34 ± 0.03 for CWT, and for RTU traits were 0.29 ± 0.04 and 0.37 ± 0.03 for UFAT, 0.31 ± 0.04 and 0.44 ± 0.03 for ULMA, and 0.45 ± 0.04 and 0.42 ± 0.03 for UIMF. Genetic correlations for AHA and ASA analyses between FAT and UFAT were 0.74 ± 0.08 and 0.28 ± 0.13, between LMA and ULMA were 0.81 ± 0.07 and 0.57 ± 0.10, and between MRB and UIMF were 0.54 ± 0.08 and 0.73 ± 0.07. Predictions of carcass merit using RTU measurements in Hereford cattle would be more reliable for FAT and LMA than MRB, but the reverse would be true for admixed Simmental cattle. Genetic correlations for MRB in AHA and for FAT and LMA in ASA are less than currently assumed in their national evaluations. Collection of greater numbers of carcass measurements would improve the accuracy of genetic evaluations for carcass traits in both breeds.

Orbital apex disorders: a case series.

Orbital apex syndrome is an uncommon disorder characterized by ophthalmoplegia, proptosis, ptosis, hypoesthesia of the forehead, and vision loss. It may be classified as part of a group of orbital apex disorders that includes superior orbital fissure syndrome and cavernous sinus syndrome. Superior orbital fissure syndrome presents similarly to orbital apex syndrome without optic nerve impairment. Cavernous sinus syndrome includes hypoesthesia of the cheek and lower eyelid in addition to the signs seen in orbital apex syndrome. While historically described separately, these three disorders share similar causes, diagnostic course, and management strategies. The purpose of this study was to report three cases of orbital apex disorders treated recently and to review the literature related to these conditions. Inflammatory and vascular disorders, neoplasm, infection, and trauma are potential causes of orbital apex disorders. Management is directed at the causative process. The cases described represent a rare but important group of conditions seen by the maxillofacial surgeon. A review of the clinical presentation, etiology, and management of these conditions may prompt timely recognition and treatment.

Evaluation of Corn Earworm, Helicoverpa zea (Lepidoptera: Noctuidae) , Economic Injury Levels in Mid-South Reproductive Stage Soybean.

Field experiments were conducted in Starkville and Stoneville, MS; Marianna, AR; Winnsboro, LA; and Jackson, TN, during 2012 and 2014 to evaluate the relationship of corn earworm, Helicoverpa zea (Boddie), larval density and yield and the relationship between the percentage of damaged pods and yield in Mid-South soybean systems. Corn earworm moths were infested into field cages at R2 for 5-11 d to achieve a range of larval densities within each plot. Larval density was estimated at 14 d after infestation. Total pods and damaged pods were determined at 19 days after infestation to obtain the percentage of damaged pods. Plots were harvested at the end of each growing season and yield recorded. Data were subjected to regression analysis, and the relationship between larval density and yield and the relationship between the percentage of damaged pods and yield both can be described by a linear relationship. Each increase of one larvae per row-m resulted in a yield loss of 45.4 kg/ha. Similarly, each increase of 1% damaged pods resulted in a yield loss of 29.4 kg/ha. From these data, economic injury levels were developed for a range of crop values and control costs. These data suggest that current corn earworm threshold use in the Mid-South should be reduced.

The Vaccination of 35,000 Dogs in 20 Working Days Using Combined Static Point and Door-to-Door Methods in Blantyre, Malawi.

An estimated 60,000 people die of rabies annually. The vast majority of cases of human rabies develop following a bite from an infected dog. Rabies can be controlled in both human and canine populations through widespread vaccination of dogs. Rabies is particularly problematic in Malawi, costing the country an estimated 13 million USD and 484 human deaths annually, with an increasing paediatric incidence in Blantyre City. Consequently, the aim of this study was to vaccinate a minimum of 75% of all the dogs within Blantyre city during a one month period. Blantyre's 25 administrative wards were divided into 204 working zones. For initial planning, a mean human:dog ratio from the literature enabled estimation of dog population size and dog surveys were then performed in 29 working zones in order to assess dog distribution by land type. Vaccination was conducted at static point stations at weekends, at a total of 44 sites, with each operating for an average of 1.3 days. On Monday to Wednesday, door-to-door vaccination sessions were undertaken in the areas surrounding the preceding static point stations. 23,442 dogs were vaccinated at static point stations and 11,774 dogs were vaccinated during door-to-door vaccinations. At the end of the 20 day vaccination programme, an assessment of vaccination coverage through door-to-door surveys found that of 10,919 dogs observed, 8,661 were vaccinated resulting in a vaccination coverage of 79.3% (95%CI 78.6-80.1%). The estimated human:dog ratio for Blantyre city was 18.1:1. Mobile technology facilitated the collection of data as well as efficient direction and coordination of vaccination teams in near real time. This study demonstrates the feasibility of vaccinating large numbers of dogs at a high vaccination coverage, over a short time period in a large African city.

Stepwise conversion of a mesophilic to a thermophilic ribozyme.

A fundamental question in RNA folding is the mechanism of thermodynamic stability. We investigated the equilibrium folding of a series of sequence variants in which one to three motifs of a 255-nucleotide mesophilic ribozyme were substituted with the corresponding motifs from its thermophilic homologue. Substitution of three crucial motifs individually or in groups results in a continual increase in the stability and folding cooperativity in a stepwise fashion. We find an unexpected relationship between stability and folding cooperativity. Without changing the folding cooperativity, RNAs having a similar native structure can only achieve moderate change in stability and likewise, without changing stability, RNAs having a similar native structure can only achieve moderate change in folding cooperativity. This intricate relationship must be included in the predictions of tertiary RNA stability.

Crystals by design: a strategy for crystallization of a ribozyme derived from the Tetrahymena group I intron.

Recently, the 2.8 A crystal structure of one domain of the self-splicing Tetrahymena group I intron was reported. Although it revealed much about RNA tertiary interactions, it contained only half of the active site. We have now designed a series of larger molecules that contain about 70% of the intron and all of the catalytic core. These RNAs were efficient in cleavage of a substrate RNA, consisting of the approximately 100 nucleotides from the 5' end of the intron, at a site corresponding to the 5' splice site. A sparse matrix was designed specifically for large RNAs and used to screen for preliminary crystallization conditions. Of the six RNAs initially tested, five were crystallized in this initial trial. Two of these crystals were further examined. The first diffracted X-rays to only approximately 16 A resolution, even when the crystal were very large. The second diffracted as high as 3.5 A, but the crystals were twinned and therefore unusable for structural studies. Site-specific mutagenesis was performed on the latter RNA to disrupt interactions that might have been responsible for the twinning. One of these mutant RNAs produced large, single, diffraction-quality crystals. The crystals belong to the tetragonal space group P42212 and have large unit cell dimensions, a=b=178 A and c=199 A. Thus, by variation of both sequence elements and crystallization conditions, crystals of a 247 nucleotide catalytic RNA were obtained.

Ribosomal proteins S5 and L6: high-resolution crystal structures and roles in protein synthesis and antibiotic resistance.

Antibiotic resistance is rapidly becoming a major medical problem. Many antibiotics are directed against bacterial ribosomes, and mutations within both the RNA and protein components can render them ineffective. It is well known that the majority of these antibiotics act by binding to the ribosomal RNA, and it is of interest to understand how mutations in the ribosomal proteins can produce resistance. Translational accuracy is one important target of antibiotics, and a number of ribosomal protein mutations in Escherichia coli are known to modulate the proofreading mechanism of the ribosome. Here we describe the high-resolution structures of two such ribosomal proteins and characterize these mutations. The S5 protein, from the small ribosomal unit, is associated with two types of mutations: those that reduce translational fidelity and others that produce resistance to the antibiotic spectinomycin. The L6 protein, from the large subunit, has mutations that cause resistance to several aminoglycoside antibiotics, notably gentamicin. In both proteins, the mutations occur within their putative RNA-binding sites. The L6 mutations are particularly drastic because they result in large deletions of an RNA-binding region. These results support the hypothesis that the mutations create local distortions of the catalytic RNA component.When combined with a variety of structural and biochemical data, these mutations also become important probes of the architecture and function of the translational machinery. We propose that the C-terminal half of S5, which contains the accuracy mutations, organizes RNA structures associated with the decoding region, and the N-terminal half, which contains the spectinomycin-resistance mutations, directly interacts with an RNA helix that binds this antibiotic. As regards L6, we suggest that the mutations indirectly affect proofreading by locally distorting the EF-Tu.GTP.aminoacyl tRNA binding site on the large subunit.