bluuebunny/crossref_metadata_2025 huggingface dataset:
Environment‐driven changes in diversity of riparian plant communities along a mountain river
Authors: Flores‐Galicia Nihaib , Trejo Irma , Ramírez‐Marcial Neptalí
Published: March 2021

The study of changes in species richness and composition along rivers has focused on large spatial scales. It has been ignored that in different sections of the river (high mountain area, middle zone, and mouth of the river) the specific environmental conditions can generate different longitudinal patterns of the species richness and composition. In this study, we determine whether species richness and composition of the riparian plant communities change along a mountain river and whether these changes are related to environmental variables. We expect an increase in species richness and turnover along the river, that the upstream communities would be a subset of the downstream communities, and that such would be related to edaphic and hydrologic conditions. To test this, we sampled three strata of the riparian vegetation (upper: individuals with <1 cm of ND, middle: individuals with >1 cm of ND, low: individuals with >1 m tall) in a set of 15 sites that we place along a mountain river. Additionally, we recorded topographic, hydrological, morphological, and soil variables. We performed correlation analyzes to determine whether changes in species richness and turnover were related to increased distance to the origin of the river. Also, we obtained the nestedness and evaluated the importance of environmental variables with GLM, LASSO regression, and CCA. With the increase in distance, the species richness decreases in the upper stratum, but not in the middle and the low stratum (although the highest values were observed near the origin of the river), the turnover increase in all strata and the upstream communities were not a subset of the downstream communities. The changes in species richness and composition were related to topographic (altitude), hydrological (flow), and edaphic (conductivity and pH) variables. Our results indicate that at small spatial scales the patterns of richness and composition differ from what has been found at larger spatial scales and that these patterns are associated with environmental changes in the strong altitude gradients of mountain rivers.
Potassium tert‐Butoxide‐Catalyzed Synthesis of α‐Methylene‐β‐Lactams from Propiolamides
Authors: Claus Angelica R. , Goulart Tales A. C. , Back Davi F. , Zeni Gilson
Published: March 2021

We reported herein the regio‐ and stereoselective synthesis of α‐methylene‐β‐lactams via a 4‐exo‐dig‐cyclization of N‐benzyl‐N‐methyl‐propiolamides catalyzed by a base. The experimental evidence suggests that this transformation proceeds via a concerted ionic cyclization with a carbon nucleophilic addition to the carbon‐carbon triple bond, followed by protonation of the vinyl species promoted by tert‐butanol. The obtained α‐methylene‐β‐lactams were suitable substrates for the Heck coupling conditions affording the corresponding products via carbon‐carbon bond formation.
Metal‐Free Direct Oxidative C−N Bond Coupling of Quinoxalin‐2(1H)‐ones with Azoles under Mild Conditions
Authors: Guo Jingwen , Zhang Lina , Du Xinyue , Zhang Liting , Cai Yuepiao , Xia Qinqin
Published: March 2021

Direct C3−H amination of quinoxalin‐2(1H)‐ones with azoles under mild conditions promoted by PIFA has been achieved in good yield in a very fast manner. Mechanistic study revealed that the reaction proceeds through a radical process. In addition, this method could be applied to gram‐scale reaction.
Shake‐table tests of innovative drift sensitive nonstructural elements in a low‐damage structural system
Authors: Bianchi Simona , Ciurlanti Jonathan , Perrone Daniele , Filiatrault André , Costa Alfredo Campos , Candeias Paulo X. , Correia António A. , Pampanin Stefano
Published: March 2021

Post‐earthquake damage reports have continuously highlighted the significant vulnerability of nonstructural elements to seismic events. Nonstructural damage has severe impact in the building recovery, increasing the socioeconomic losses even for low intensity events. In the last few years, research efforts have focused on the development of innovative nonstructural solutions, to be combined with damage‐resistant structural skeletons in order to obtain an overall high‐performance building. As part of a European Union (EU)‐funded project, the effectiveness of such integrated skeleton&envelope low‐damage system in reducing the earthquake related losses was investigated. Tridimensional shake table tests on a 1:2 scaled timber‐concrete low‐damage structural skeleton, “dressed” by different innovative nonstructural elements (glass/concrete facades, gypsum/masonry partitions), were performed at the National Laboratory for Civil Engineering (LNEC) in Lisbon, Portugal. The shake table tests were carried out at increasing seismic intensities to investigate the structural and nonstructural performance up to a higher‐than Collapse Prevention Limit State according to the Italian Code (975 years return period). This paper focuses on the dynamic behavior of nonstructural elements with detailed discussion on construction detailing, seismic demand and performance of the innovative solutions. The high performance of nonstructural elements proved the potential of the details introduced in the partitions/facades. Minimal or no damage was observed up to the end of the overall testing sequence, which reached moderate‐to‐high interstory drift ratios (more than 1.00%) ‐ typically expected to cause severe damage to traditional nonstructural partitions/infills/facades.
Value‐aware cache replacement in edge networks for Internet of Things
Authors: Peng Ting , Wang Haohao , Liang Cangming , Dong Pingping , Wei Yehua , Yu Jianping , Zhang Lianming
Published: March 2021

With the development of Internet of Things (IoT), massive amounts of data will be brought. By offloading caching from the cloud to the edge, edge caching technology represents a promising solution in the era of IoT to meet the delay requirements of IoT applications. An efficient cache decision and replacement strategy on edge caching devices is a key factor in ensuring the cache hit ratio. The existing cache replacement policies do not comprehensively consider the characteristics of cache files and are likely to result in cache pollution problems. In order to cache data reasonably, to improve the cache hit ratio, and to reduce the user request delay, we propose a concept of file cache value and a file cache value‐aware cache replacement (FCVACR) algorithm of the edge cache system in this article. File cache value is associated with three aspects of cache file: the file size, the file popularity, and the time of requests. The proposed FCVACR algorithm adopts the file cache value method, improves the utilization of edge caching space, and reduces the content transmission delay. Experimental results show that the proposed FCVACR algorithm has a higher cache hit ratio and lower user request delay than the classical cache replacement algorithms.
Effects of investor attention in China's commodity futures markets
Authors: Wu Ming‐Hung , Tsai Wei‐Che , Weng Pei‐Shih , Li Dan‐Yi
Published: March 2021

This paper analyzes the impacts of investor attention on the returns and volatility of commodity futures in China. Using online search volumes as a proxy for investor attention, we find that investor attention exhibits a positive contemporaneous relationship with returns and volatility. In addition, the online search variables are significant predictors of returns and volatility in the commodity futures markets. Moreover, as compared with personal computer searches, mobile searches have a more pronounced predictive effect on returns and volatility. Taken together, we suggest that investor attention can explain the concurrent price movement and variation in the commodity futures markets in China.
Increased aridity across thePermian–Triassictransition in the mid‐latitudeNEPangea
Authors: Cui Can , Cao Changqun
Published: March 2021

The Dalongkou section in Xinjiang, Northwest China has preserved a continuous terrestrial Late Permian–Early Triassic sequence with well‐studied information of biota evolution and isotopic excursion. In order to know the corresponding palaeoclimatic and palaeoenvironmental evolution in this critical transition, chemical weathering indexes (chemical index of alteration [CIA], plagioclase index of alteration [PIA], and chemical index of weathering (CIW)) are analysed in high resolution across the Permian–Triassic Boundary. Results show that the declining trend of the CIA, PIA, and CIW was related to the continuous decrease of the chemical weathering in the latest Permian. The climate in the mid‐latitude NE Pangea was becoming increasingly arid in a generally greenhouse warm climate, causing widespread wildfire and turnover of the fauna and biota, coupled with the environmental deterioration expressed by the anomalies of carbon and mercury. Climatic conditions oscillated in the Early Triassic with possible intermittent rainfall and was likely affected by the strengthening of the megamonsoon. In the latest Permian–earliest Triassic, whether chemical weathering strengthened or weakened, as well as whether the climate was increasingly arid or humid, varied in the different places. The possible reasons inducing this need to be further explored.
Social informal learning and the role of learning climate: Toward a better understanding of the social side of learning among consultants
Authors: Crans Samantha , Bude Veronika , Beausaert Simon , Segers Mien
Published: March 2021

This research examines the social side of learning among professionals in the fast evolving and knowledge intense field of consultancy. Its first aim is to unravel social informal learning by proposing a new, integrated framework of workplace learning. Its second aim is to explore the role of learning climate for social informal learning behavior among consultants. Our qualitative inquiry using interviews based on the critical incident technique illustrates that consultants engaged in deliberative and reactive learning, thereby indicating a clear intention to learn. The source of learning was often the direct colleagues and direct supervisor, which highlights the relevance of close proximity of other individuals. The consultants mainly learned from others in a passive manner, followed by proactive and collaborative learning. Finally, this study shows that granting professionals responsibility and autonomy in their learning process as well as having a leader who facilitates learning are important elements of a learning climate that enhances social informal learning. We conclude with recommendations for organizations and directions for future research.
Peristaltic motion with heat and mass transfer of nano‐Williamson fluids in two layers
Authors: Shawky Hameda M. , Eldabe Nabil T.
Published: March 2021

In this paper, we have investigated the peristaltic motion with heat and mass transfer through a vertical channel divided into two equal regions, the right region filled with a clear non‐Newtonian fluid obeying the Williamson model and the left region with a nano‐Williamson fluid. The system is stressed by a gravity force with a uniform external magnetic field. The problem is modulated mathematically with a system of coupled nonlinear partial differential equations that describe the velocities, temperatures, and concentration of the fluids. The system of nondimensional, nonlinear, and partial differential equations is solved analytically with the homotopy perturbation method after using the approximations of low Reynolds number and long wavelength. The obtained solutions are functions of the physical parameters of the problem. Then, the effects of these parameters on velocities, temperatures, and concentration are discussed numerically and illustrated graphically through a set of figures. It is found that the parameters play an important role in controlling the solutions. It is shown that the stream function decreases on the left side and increases on the right side with an increase in the Wissenberger parameter and thermal conductivity ratio. Also, the temperature in the two regions increases with an increase in the thermophoretic parameter, whereas it decreases with an increase in the Brownian motion parameter. Furthermore, the concentration increases with an increase in the Brownian motion parameter and decreases with an increase in the thermophoretic parameter.
Characterization of subsurface fluxes at the plot scale during flash floods in the Valescure catchment, France
Authors: Bouvier Christophe , Adamovic Marko , Ayral Pierre‐Alain , Brunet Pascal , Didon‐Lescot Jean‐François , Domergue Jean‐Marc , Spinelli Rosario
Published: March 2021

This study focuses on a 10‐m2 plot within a granitic hillslope in Cevennes mountainous area in France, in order to study infiltration and subsurface hydrological processes during heavy rainfalls and flash floods. The monitoring device included water content at several depths (0–70 cm for the shallow soil water; 0–10 m for the deep water) during both intense artificial and natural rainfall events, chemical and physical tracers, time‐lapse electrical resistivity tomography. During the most intense events, the infiltrated water was estimated to be some hundreds of millimetres, which largely exceeds the topsoil capacity (≤40 cm deep in most of the cases). The weathered/fractured rock area below the soil clearly has an active role in the water storage and sub‐surface flow dynamics. Vertical flow was dominant in the first 0–10 m, and lateral flow was effective at 8–10 m depth, at the top of the saturated area. The speed of the vertical flow was estimated between 1 and 10 m/hr, whereas it was estimated between 0.1 and 1 m/hr for the lateral flow. The interpretation of the experiments might lead to a local pattern of the 2D‐hydrological processes and profile properties, which could be generic for most of the mountainous catchments under Mediterranean climate. It suggests that fast triggering of floods at the catchment scale cannot be explained by a mass transfer within the hillslope, but should be due to a pressure wave propagation through the bedrock fractures, which allows exfiltration of the water downstream the hillslope.
Quantifying ice storage in upper Indus river basin using ground‐penetrating radar measurements and glacier bed topography model version 2
Authors: Zou Xiaojuan , Gao Haifeng , Zhang Yinsheng , Ma Ning , Wu Jianfeng , Farhan Suhaib Bin
Published: March 2021

Ice reserve estimates is a fundamental prerequisite for water resources management. We selected the UIB (upper Indus river basin) as study area because it contains the most abundant mid‐latitude glaciers outside the polar region, however, the ice reserve estimates remain unclear due to the harsh topography. In this study, we validated the parameters of the GlabTop2 model (Glacier Bed Topography version 2) using the ice thickness measured by GPR (ground‐penetrating radar) and compared the “GPR‐measured ice thickness and ice bed elevation” versus “the estimated results obtained from GlabTop2.” Integrated with IDW (inverse distance weighted) interpolated results of glaciers of various sizes, a reasonable parametric scheme (τ = 120 kPa and f = 0.8) of GlabTop2 was applied on vast amounts of glaciers in the UIB region. The GlabTop2 estimates indicated that the ice thickness of the UIB varied from 0 to 736.0 ± 110.0 m, with an average value of 74.5 ± 11.2 m. A significant spatial heterogeneity exists in the sub‐basins. The Shyok, Shigar and Hunza that contain the most abundant ice reserve. Lesser quantities are stored in the Western Himalaya and Hindu Kush ranges, which account for 11.3 % and 6.7 % of the total ice reserve in the UIB, respectively. A total volume of 1162.4 ± 175.1 km3 of glacier can be converted to 1046.2 ± 157.6 Gt ice reserve; this is 13.6 times the annual average discharge obtained from the outlet of the Besham hydrological station. We aim to present estimates that can provide the baseline information for glaciology study of the Indus river.
The Bear Brook Watershed in Maine: Multi‐decadal whole‐watershed experimental acidification
Authors: Patel Kaizad F. , Fernandez Ivan J. , Nelson Sarah J. , Norton Stephen A. , Spencer Cheryl J.
Published: March 2021

The Bear Brook Watershed in Maine (BBWM) is a long‐term research site established to study the response of forest ecosystem function to environmental disturbances of chronic acidic deposition and ecosystem nitrogen enrichment. Starting in 1989, the West Bear (treated) watershed received bimonthly applications of ammonium sulfate [(NH4)2SO4] fertilizer from above the canopy, whereas East Bear (reference) received ambient deposition. The treatments were stopped in 2016, marking the beginning of the recovery phase. Research at the site has focused on soils, streams, and vegetation. Here, we describe data collected over three decades at the BBWM—input and stream output nutrient fluxes, quantitative soil pits and soil chemistry, and soil temperature and moisture.
Pyricularia oryzae incites gray leaf spot disease on hard fescue (Festuca brevipila)
Authors: Vines P. L. , Daddio R. M. , Luo J. , Wang R. , Murphy J. A. , Zhang N. , Clarke B. B. , Meyer W. A. , Bonos S. A.
Published: March 2021

Gray leaf spot, caused by the fungal pathogen Pyricularia oryzae, is a widespread and destructive foliar disease of turfgrasses in the United States. Characteristic gray leaf spot disease symptoms were observed on hard fescue (Festuca brevipila Tracey) turf in New Jersey during October 2018. Prior to this observation, P. oryzae had not been documented as a pathogen of F. brevipila. Therefore, this study was conducted to determine if P. oryzae was the cause of the observed gray leaf spot disease symptoms. Morphological assessments and molecular analyses identified fungal isolates as the potential incitant from symptomatic F. brevipila turf as P. oryzae. Two isolates of P. oryzae (D300452 and 181001P12) and two F. brevipila cultivars (‘Beacon’ and ‘Reliant IV’) were used in growth chamber studies to fulfill Koch's postulates for pathogenicity. Inoculations were carried out using conidial suspensions at 4 × 104 conidia ml−1 concentration. Disease symptoms were observed 7 d post‐inoculation for both isolates on both cultivars. Koch's postulates were fulfilled by morphological evaluations and DNA sequencing of the reisolated fungi. This study confirms that P. oryzae is the causal agent of gray leaf spot disease on F. brevipila. Given the historical significance of gray leaf spot disease in other turf species, this study suggests that gray leaf spot could be a major concern for managing F. brevipila turf in the future.
Evaluation and genetic analysis of red thread (Laetisaria fuciformis) disease prevalence in tall fescue (Festuca arundinacea)
Authors: Qu Yuanshuo , Green Edwin J. , Vines Phillip L. , Wu Shidi , Clarke Bruce B. , Bonos Stacy A. , Meyer William A.
Published: March 2021

Red thread, caused by [Laetisaria fuciformis (Berk.) Burds.], is a common disease on many cool‐season and some warm‐season grasses throughout the world. Low reproducibility of experiments under both natural and artificial infection and inadequate understanding of the underlying genetics have limited the selection of turfgrass for resistance to red thread. This study investigated red thread prevalence of tall fescue (Festuca arundinacea Schreb.) populations in two locations over multiple years, estimated disease prevalence in a broad collection of tall fescue populations, and calculated heritability of disease prevalence with two different experimental designs. Collections from Albania and Romania, as well as those that were recently backcrossed to adapted germplasm, were more susceptible to red thread compared with the rest of the populations, highlighting the importance of selection efforts against red thread disease in tall fescue. Narrow‐sense heritability (0.52, 0.74, and 0.48) estimated from different experimental designs were all in the range of moderate to high, indicating a large proportion of additive genetic variance in red thread prevalence among tall fescue populations. Hence, prevalence of red thread in tall fescue can be effectively reduced through selection and breeding. This is also the first report documenting the efficacy of family selection in reducing red thread prevalence in tall fescue.
Etiology and management of Pythium root rot in golf course putting greens
Authors: Hampy Halle D. , Van Ryzin Benjamin J. , Butler E. Lee , Kerns James P.
Published: March 2021

Pythium root rot (PRR), caused by various Pythium species, is a major disease of creeping bentgrass in the transition zone of the United States. Characterization of various Pythium species associated with PRR was determined by identifying 106 Pythium isolates from samples of symptomatic turfgrass cores. Pathogenicity assays were conducted on post‐emergent (7‐day old) seedlings and mature (5‐week old) creeping bentgrass plants that were inoculated with four different Pythium spp. and incubated at 34 ℃/28 ℃ for 1 to 5 weeks. The results demonstrated that pathogenicity on post‐emergent seedlings may not correlate with pathogenicity on mature plants. The sensitivity of various Pythium spp. to ten commercially available fungicides was determined through in vitro mycelial growth assays. Isolates (n = 20) varied in sensitivity to fungicides across and within species of Pythium. Management of PRR was determined through field experiments, revealing that cyazofamid‐based treatments were most effective when applied preventatively in the early summer, and were able to reduce disease severity when applied curatively.
Effects of nitrogen, phosphorus and potassium rates on Microdochium patch
Authors: McDonald Brian , Kowalewski Alec , Mattox Clint , Braithwaite Emily , Schmid Charles
Published: March 2021

Research on nitrogen (N), phosphorus (P) and potassium (K) ratios have suggested that maintaining the proper balance of those nutrients is critical to disease mitigation. However, research on N, P, and K ratios relevant to annual bluegrass (Poa annua L.) and Microdochium patch (Microdochium nivale) is not available. The objective of this research was to evaluate the effects of winter‐applied N, P, and K rates in combination with sulfur and phosphorous acid on Microdochium patch development within an annual bluegrass putting green in the absence of traditional fungicides. Field research was conducted from October 2018 to April 2019 on a mature sand‐based annual bluegrass putting green. Factors included monthly applications of urea nitrogen (46–0–0) rate (4.9 kg N ha–1 and 9.8 kg N ha–1), phosphorus rate (0.0 kg P ha–1 and 1.22 kg P ha–1), and potassium rate (0.0 kg K ha–1 and 4.9 kg N ha–1). To avoid extreme disease levels, all of these treatments received monthly applications of phosphorous acid. When comparing nitrogen treatments across both rates vs. nitrogen combined with P, K or both, disease levels decreased from 9.9 percent (urea only) to 5.5 percent (urea with P, K, or both). Additionally, when nitrogen rates increased from 4.9 kg N ha–1 to 9.8 kg N ha–1, the percent disease decreased from 8.4 to 4.8 percent. Findings from this project suggest that applying nitrogen only as urea will lead to more Microdochium patch vs. applying urea with P, K, or both, and nitrogen applied at the higher rate will decrease Microdochium patch incidence.
Genetic identity and diversity among experimental selections and cultivars of vegetatively propagated turf bermudagrass as assessed with SSR markers
Authors: Godwin Carly , Fang Tilin , Wu Yanqi
Published: March 2021

Turf bermudagrass (Cynodon spp.) is the most common, warm‐season, sod‐forming perennial grass for residential lawns, sports fields, golf courses, and public landscapes in warm climates across the world. Genetic diversity and identity information are important for breeding new cultivars and production certification. Accordingly, this experiment was designed to genotype experimental selections along with commercial cultivars to analyze their genetic diversity. Nineteen advanced selections from the Oklahoma State University (OSU) turfgrass breeding program and 13 cultivars were used in the genetic analysis. Fifty‐four simple sequence repeat (SSR) primer pairs (PPs) selected across the bermudagrass genome produced 618 polymorphic PCR fragments, of which 120 fragments amplified by using 48 SSRs were unique to the 19 experimental selections. Genetic similarity coefficients varied from 0.69 to 1.00. The AMOVA results indicated 94% of the variation resided within the selections or cultivars. The UPGMA analysis showed that groupings were associated with origins of their parental germplasm. The seventeen distinct experimental selections identified were genetically different from all commercial cultivars tested, demonstrating the potential of adding genetic diversity to the existing cultivar pool if one or more of the experimental genotypes are released for commercial production.
SCANTURF ‐ Evaluation of turfgrass varieties for lawns and sports grounds in Scandinavia
Authors: Havstad Lars T. , Niskanen Markku , Larsen Anders S. , Aamlid Trygve S.
Published: March 2021

SCANTURF is a joint Nordic programme for turfgrass variety testing, set up in 2005 and funded by variety entrance fees only. It replaced and simplified the former government‐funded national evaluation programmes in Finland, Sweden, Denmark and Norway. The programme includes testing of all cool‐season grasses on lawn/fairways at 15–20 mm mowing height (“lawn trials”) and optional testing of Poa pratensis L. and Lolium perenne L. on simulated football pitches with wear, mowed at 30 mm (“wear trials”). Since 2013, the program has regarded the Nordic countries as one trial zone with three test sites: Tystofte Denmark (55°15′ N, 11°20′ E), Landvik, Norway (58°21’ N, 8°32’ E) and Ylistaro, Finland (62°57′ N, 22°31’ E). Wear trials are carried out at the intermediate location Landvik only. Candidate varieties are tested against two reference varieties of the same species or subspecies. In the lawn trials, candidate varieties are evaluated for visual merit (overall turfgrass quality), winter damage, winter color, diseases and daily height growth at all three locations and for tiller density, fineness of leaves, in‐season (genetic) color, at Landvik only. Based on the results from the SCANTURF trials in 2014–2016 and 2016–2018, the candidate varieties Fabian, Tetrastar, Annecy, and Monroe (Lolium perenne), Becca, Harmonie, Traction, and Markus (Poa pratensis) and Lystig, Greenmile, and Humboldt (Festuca rubra ssp. commutata) were recommended for lawns in the Nordic countries, while Eurocordus, Columbine, Monroe, and Annecy (Lolium perenne) and Harmonie (Poa pratensis) were recommended for sports grounds. More use of the recommended varieties will have a positive effect on quality of lawns and sport grounds in the Nordic countries. Less winter injury and increasing relative performance with increasing latitude of the tetraploid perennial ryegrass variety Fabian in the lawn trials may possibly lead to more use of perennial ryegrass in the northern and more continental parts of the region.
Evaluating biological thatch control in turfgrass
Authors: Weaver Josh R. , McCarty Lambert B. , Quisenberry Virgil L. , Hubbard L. Ray , Bridges William G. , Brown Philip J.
Published: March 2021

Thatch is a layer of living and dead plant material between turfgrass leaf tissue and soil surface; it can decrease playability, increase scalping and disease pressure, reduce pesticide efficacy and water infiltration, plus harbor insects. In golf putting greens, disruptive mechanical practices such as vertical mowing, core cultivation, grooming, and topdressing are traditionally used for managing thatch; however, several biological products have been marketed as non‐disruptive thatch reducers. Greenhouse experiments were conducted to evaluate thatch reduction and rooting depth of two commercial humic acid based biostimulant products, Worm Power (WP) and EarthMAX (EM). Products were applied at labelled rates and timings. EM was applied at two rates, indicated as EM (1) and EM (2). Two industry standards were also included: blackstrap molasses and sand topdressing. For both years, blackstrap molasses, EM (1), and EM (2) reduced thatch thickness compared to untreated by 30, 24, and 18% respectively. However, no decrease in thatch weight by treatment was observed. In Year 1, EM (1), and sand topdressing provided an average of 16% greater root length than untreated. However, in Year 2, WP provided 16% greater root length than untreated. EM (1) provided 117% greater root mass than untreated control in Year 2. No treatment provided greater root mass in Year 1. Thatch depth reduction indicate these products may be beneficial, but, inconsistent results mean further research is required.
Aboveground and belowground traits of turf‐type bahiagrass (Paspalum notatum Flügge) genotypes under simulated drought
Authors: Boeri P. Agustin , Unruh J. Bryan , Kenworthy Kevin E. , Trenholm Laurie E. , Rios Esteban F.
Published: March 2021

As awareness of environmental impacts of anthropogenic ecosystems increases, low input turfgrass species like bahiagrass (Paspalum notatum Flügge) may become more prominent in urban landscapes and on golf courses. A study was conducted at the West Florida Research and Education Center, Jay, FL, USA, to evaluate the performance of novel turf‐type bahiagrass genotypes under drought conditions. The experiment was arranged as a completely randomized block design. Three Wilmington‐mutants, three Argentine‐mutants, two experimental lines, and two industry standards [‘Argentine’ and ‘Empire’ zoysiagrass (Zoysia japonica Steud.)] were selected for this trial. Aboveground and belowground characteristics were evaluated by growing the grasses in clear acrylic tubes under greenhouse conditions. A progressive dry‐down and well‐watered control comprised the treatments. The tubes were weighed daily to determine their transpiration break and midpoints. The rate of root depth development (RRDD) was recorded by measuring the single visible deepest root. At the end of the dry down, plant roots were harvested and analyzed using WinRhizo. Although total root growth was reduced under drought conditions, plants tended to have faster vertical root growth and prioritized root development in the lower soil depths. Root length density (RLD) and the distribution of RLD in the lower soil depths, fast RRDD, and high transpiration midpoints were the most important drought responsive traits. These attributes were consistently observed on genotypes WilM10 and ArgM27.
Sod production characteristics: How strong is your bermudagrass?
Authors: Segars Chrissie A. , Moss Justin Quetone , Martin Dennis L. , Wu Yanqi
Published: March 2021

For new, vegetatively propagated turfgrass cultivars to be successful in the marketplace, they must not only possess characteristics desired by the end user, but also have those preferred by the sod producer. The objectives of this study were (1) to investigate different sod production characteristics of advanced clonal bermudagrass [C. dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy] lines that show improved characteristics and (2) to examine the relationship between those production characteristics. Production characteristics measured include: sod handling quality (SHQ), sod tensile strength (STS), vertical growth (VG), and underground growth characteristics. Results showed a positive correlation (r2 = 0.65) between SHQ and STS. Other production characteristics moderately correlated or did not correlate at all. Knowledge of growth characteristics can aid breeders in choosing breeding lines that will add value to the sod industry.
Empirical and theoretical assessment of mechanical and injection cultivation methods to manage white grubs in turfgrass
Authors: McGraw Benjamin A. , Price Garrett , Simard Audrey , Trotta Kevin
Published: March 2021

White grubs, or the larvae of scarab beetles, are widespread destructive pests of turfgrass systems around the world. We sought to determine if turfgrass cultivation machinery could reliably manage white grubs in turfgrass systems. Hollow‐tine aeration provided greater reductions in grub densities than solid‐vibratory tine and air/solid injection cultivation in field trials. In following studies, low to moderate reductions (0–53%) were observed with single hollow‐tine applications, though low grub densities encountered within field plots hindered the ability to detect statistical differences between cultivation treatments including tine diameter and tine spacing. Increasing aerification frequency on plots from one to two or more passes produced statistically significant reductions (>80% control) in both years of trials. To eliminate the variability observed in the field, a simulation model was constructed to determine the expected outcome of varying tine patterns have on increasing grub densities. Models suggests that expected mortality is likely to be minimal (<10%) in one‐time aerification events. In‐field simulations using templates overlaid on natural populations demonstrated two‐fold greater control than theoretical simulations. Differences in control between field studies and model simulation are likely caused by an over‐estimation of mortality when performing presence‐absence counts in field studies when grub densities are low. Although multiple aerification events will likely improve control, current cultivation practices are unlikely to achieve the level of control expected by turfgrass managers in intensely managed landscapes.
Utilizing organic amendments for general suppression of dollar spot on creeping bentgrass turf
Authors: Beckley Cody James , Roberts Joseph Anthony
Published: March 2021

Dollar spot (Clarireedia spp.) negatively impacts the aesthetic value and playability of golf course fairways. A 2‐yr field trial was conducted to examine organic amendment effect on dollar spot severity and on fungicide residual efficacy for dollar spot control on creeping bentgrass (Agrostis stolonifera L. ‘007’). Treatments were arranged in a 7 × 5 split‐plot factorial measuring the effect of fertilizer source (soil incorporated organic biosolids compost, soil incorporated biochar, surface applied organic biosolids compost, surface applied biochar, vermicompost extract, standard fertilizer, or non‐treated) on control of dollar spot by five fungicide treatments (fluazinam 14 d, fluxapyroxad 14 d, fluazinam threshold, fluxapyroxad threshold, none) applied at product label rates. Nitrogen fertility levels for all treatments were standardized at ∼205 kg N ha–1 annually. Threshold fungicide treatments were applied when three or more infection centers per area were counted on two or more of four trial replicates. In 2017, all fertilizer treatments were significantly more effective at reducing disease than non‐treated, but were statistically similar. In 2018, biochar, vermicompost, and standard fertilizer treatments were significantly more effective than organic biosolids compost and non‐treated. Fungicides controlled dollar spot when applied every 14 d. In 2017, all fertilizer treatments reduced the number of threshold sprays compared to none, yet the same effects were not consistently observed in 2018. Study results illustrate the effectiveness of nitrogen application for mitigating dollar spot disease on creeping bentgrass during establishment compared to no fertilizer, potentially allowing for reduced fungicide use to control the disease.
A cross‐disciplinary forum promoting efficient biodiversity conservation in “new” grasslands in Sweden
Authors: Gylje Blank Sofia , Svensson Mikael , Strandberg Maria
Published: March 2021

Due mainly to changes in land use, high nature value grasslands are becoming increasingly rare in agricultural areas. As a consequence, biodiversity is decreasing and many species are facing the risk of extinction. At the same time, the present‐day landscape contains many “new” grassland habitats, for example golf courses, roadside verges, power line corridors, and railway banks. These habitats are well distributed over the landscape with a potential to connect remnant patches of valuable grasslands. As all kinds of grasslands, they need appropriate management to preserve biodiversity. To achieve this, innovative solutions are needed. In order to exchange knowledge and experiences in this field, we established a cross‐disciplinary working group, with members from a large number of National authorities, Universities, power grid companies, and various other stakeholders such as the Swedish Golf Federation. This group has become an invaluable forum for project cooperation and discussions about practical management issues, monitoring, and research. After 10 years we are now approaching a common understanding on how infrastructure habitats can play an important role in nature conservation. At present, this has led to adaptive management of a large number of high value grasslands, for example in power line corridors, along roadside verges, and on golf courses. In addition, three landscape‐scale projects have been initiated with the long‐term aim to establish a green infrastructure.
Plant growth regulator effects on winter hardiness of annual bluegrass putting green turf
Authors: DaCosta Michelle , Ebdon J. Scott , Miele Kevin , Bernstein Rachael P. , Inguagiato John C.
Published: March 2021

Cold deacclimation sensitivity has been cited as an important factor associated with winterkill susceptibility of annual bluegrass (Poa annua L.). Increased potential for deacclimation for this species has been attributed to higher metabolic activities in response to warm winter temperatures. We hypothesized that using plant growth regulators to inhibit turfgrass growth and metabolism during winter months could potentially suppress premature deacclimation and increase survival of annual bluegrass. The specific objectives of this study were to examine the effects of varying rates of autumn‐applied trinexapac‐ethyl (TE) and prohexadione‐Ca (PC) on winter hardiness and spring recovery of an annual bluegrass putting green. The study was conducted over the winters of 2015–2016 and 2016–2017. Treatments included an untreated control and four rates of TE (0.05, 0.10, 0.2, and 0.4 kg a.i. ha–1) and PC (0.06, 0.12, 0.25, and 0.50 kg a.i. ha–1). Freezing tolerance was assessed based on controlled freeze tests to estimate the lethal temperature resulting in 50% regrowth (LT50). General turfgrass health was also assessed based on visual turf quality and normalized difference vegetation index (NDVI). Late‐autumn PGR applications impacted the freezing tolerance of annual bluegrass during Year 1, but no treatment effects were detected in Year 2. Plant growth regulator treated turf, pooled over chemicals and rates, exhibited lower freezing tolerance (Year 1), turf quality, and NDVI (Years 1 and 2) compared to untreated turf particularly at the higher application rates. By the end of May in both years, all treatments recovered to the same levels.
Comparison of adsorption behaviors of selected endocrine‐disrupting compounds in soil
Authors: Rivas Chen Fritzie , Chefetz Benny , Thompson Michael L.
Published: March 2021

Bisphenol‐A (BPA), 17α‐ethinylestradiol (EE2), and 4‐nonylphenol (4NP) are endocrine‐disrupting chemicals (EDCs) that are useful models for studying the potential fate and transport of EDCs in soil and water environments. Two alluvial soils with contrasting physicochemical properties were used as adsorbents for this study. The Zook soil material had more organic matter and clay than the sandy loam Hanlon soil material. Batch equilibrium experiments were performed to generate adsorption isotherms, to determine the adsorption parameters, and to assess desorption hysteresis. Adsorption of BPA to both soils followed an L‐type isotherm, and 4NP adsorbed to both Hanlon and Zook soils exhibited S‐shape isotherms. EE2 adsorbed to the Zook soil also followed an S‐shaped isotherm, but EE2 adsorbed to the Hanlon soil showed an H‐type isotherm. Overall, the Sips model fit the data well, with standard errors of prediction generally ≤6%. The adsorption affinity (KLF) values were highest for 4NP, and BPA had the lowest hysteresis indices. The data suggest that BPA was most likely adsorbed by soil organic matter via hydrogen bonding involving its two phenolic groups. In contrast, isotherm shape, model affinity indices, lack of desorption, and molecular‐scale characteristics led us to infer that 4NP was adsorbed largely by the retention of molecular clusters, perhaps in clay nanopores. Finally, the adsorption of EE2 exhibited different isotherm shapes for the two soils as well as intermediate affinity and desorption indices, suggesting that EE2 molecules could be retained both by soil organic matter and by clay.
Long‐term outcomes of anti‐tumor necrosis factor therapy and surgery in nonperianal fistulizing Crohn's disease
Authors: Vuyyuru Sudheer K , Desai Devendra , Kedia Saurabh , Dhoble Pavan , Sahu Pabitra , Kante Bhaskar , Agarwal Samagra , Bopanna Sawan , Dhingra Rajan , Venigalla Pratap Mouli , Sharma Raju , Gupta Siddhartha Datta , Makharia Govind , Sahni Peush , Ahuja Vineet
Published: March 2021

Background

Unlike perianal fistula, long‐term outcomes of nonperianal fistulae (NPF) in Crohn's disease (CD) are not clear. We aimed to compare the outcomes of medical and surgical therapies in patients with NPF.

Methods

We retrospectively analyzed the records of patients of CD with NPF who were prospectively followed from January 2005 to December 2018.

Results

Of the 53 patients with NPF [mean age at presentation:29 ± 14 years; 54.7% male; median duration of follow‐up: 47 months (interquartile range [IQR]:26–76 months)], enteroenteric fistula (37.8%) was the most common presentation. Of 22 patients treated with anti‐tumor necrosis factor (TNF) therapy, complete response was achieved in 40.9% (n = 9). Overall probability of maintaining response was similar between the anti‐TNF and surgical groups (95.2% vs 82.4%; 71% vs 76%; and 63% vs 69%% [P = 0.8] at 1, 2, and 3 years, respectively), with only 13.6% of patients treated with biologicals requiring surgery over 56 months. Twenty‐one patients required upfront surgery (small bowel or ileocolonic resection with/without diversion; 28.5% emergent), with 47.6% postoperative recurrence over 36 months, of which nine patients required biologicals (77.7% response to anti‐TNF therapy). Long‐term outcome was comparable between medically and surgically treated patients; 6.4% developed tuberculosis on anti‐TNF therapy. Two patients (3.7%) developed malignancy (one ‐ enteroenteric, one ‐ colovesical).

Conclusion

Anti‐TNF therapy appears to be as effective as surgery in this retrospective analysis of patients with NPFCD, and it may be indicated in the absence of abscess and other complications. These patients are at higher risk of fistula‐associated malignancy, which requires a lower threshold for suspicion, especially over the long term in the presence of nonresponse to medical therapy.
Clinical characteristics and risk factors of gastroesophageal reflux disease in Vietnamese patients with upper gastrointestinal symptoms undergoing esophagogastroduodenoscopy
Authors: Quach Duc T , Pham Quyen T T , Tran Truc L T , Vu Nhu T H , Le Quang D , Nguyen Doan T N , Dang Ngoc L B , Le Huy M , Le Nhan Q
Published: March 2021

Background and Aim

The risk factors associated with the increase in prevalence of gastroesophageal reflux disease (GERD) are not consistent across countries and there have been few studies in Asia in the past 10 years. This study was conducted to assess the features and risk factors of GERD in Vietnamese patients.

Methods

A cross‐sectional study was conducted on 1947 out‐patients ≥18 years of age who were presented with upper gastrointestinal symptoms and underwent esophagogastroduodenoscopy. Reflux esophagitis was graded according to the Los Angeles classification. Endoscopically suspected Barrett's esophagus (BE) was recorded according to the Prague C and M criteria and biopsy was taken for histologic examination.

Results

There were 511 (26.2%) patients with GERD, 242 (47.4%) with nonerosive reflux disease, and 269 (52.6%) with reflux esophagitis and/or BE. Epigastric pain, regurgitation, and heartburn were the chief complaints in 36.8%, 27.0%, and 9.2% of patients, respectively. Most of the patients with mucosal injury had reflux esophagitis in mild grade and BE in the form of C0M ≤2 (99.6%, 231/232 and 97.8%, 46/47, respectively). In multivariate analysis, hiatal hernia, male gender, waist‐to‐hip ratio (independent from general obesity), and smoking were risk factors for GERD while Helicobacter pylori infection was negatively associated with GERD.

Conclusions

The majority of GERD patients had none or mild mucosal injury. Typical reflux symptoms, however, may not be the chief complaints. Central obesity would be more important than general obesity as a risk factor, while H. pylori infection was a “protective” factor for GERD in Vietnamese patients.
Prospective randomized controlled trial of omental roll‐up technique on pancreatojejunostomy anastomosis for reducing perioperative complication in patients undergoing pancreatoduodenectomy
Authors: Tangtawee Pongsatorn , Mingphruedhi Somkit , Rungsakulkij Narongsak , Suragul Wikran , Vassanasiri Watoo , Muangkaew Paramin
Published: March 2021

Background

Wrapping pancreatojejunal anastomosis with omentum to prevent postoperative pancreatic fistula (POPF) has only been reported in non‐randomized, controlled trials. Therefore, this study aimed to conduct a randomized, controlled trial to compare outcomes between omental roll‐up and non‐omental roll‐up in pancreatojejunal anastomosis.

Methods

This single‐center, randomized, two‐arm trail (Clinical Trials Register: NCT03083938) was conducted between February 2017 and February 2019. We studied 34 patients in the omental roll‐up group and 34 patients in the non‐omental roll‐up group. The primary endpoint was the incidence of clinically relevant POPF. Thirty‐day mortality and morbidity were recorded.

Results

Patients’ demographic data were not significantly different between the two groups, except for histological diagnosis, with a significantly higher incidence of pancreatic cancer in the omental roll‐up group (n = 15, 44.1%) than in the non‐omental roll‐up group (n = 9, 26.4%) (P = 0.042). There was one death in the non‐omental roll‐up group due to myocardial infarction. The incidence of POPF was not different between the omental roll‐up group (n = 5, 14.7%) and non‐omental roll‐up group (n = 7, 20.6%) (P = 0.525). No differences were found in postoperative hemorrhage after pancreatectomy, delayed gastric emptying, and chyle leakage between the groups.

Conclusion

This study shows that omental roll‐up does not decrease the incidence of POPF after pancreatoduodenectomy.