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While the basic sequence of innovations that characterise ceramic production in southern Britain during the first centuries b.c. and a.d. is well-established, our understanding of resistance to these innovations remains in its infancy. Led by the theoretical principles of social constructionism, this paper presents a detailed technological characterisation of Silchester ware, a hand-built ceramic type common in late Iron Age and early Roman Berkshire and northern Hampshire, and a conspicuous example of technological and stylistic anachronism when compared to contemporary wheel-made pottery. Multi-period analyses using radiography, petrography and typology indicate that Silchester ware was not merely a technological ‘hangover’, but a traditional form of material culture with its own role in changing socio-economic structures. Contextualisation of the findings within the local archaeological background further suggests that Silchester ware may have been instrumental in the maintenance of local community and identity at a time when these aspects of social life were under threat. Supplementary material available online (https://doi.org/10.1017/S0068113X20000355) comprises a characterisation of the chaînes opératoires of Silchester ware and its middle Iron Age antecedents, and a summarised version of the data, interpretations and the original radiographs.
The WSSA group 15 (HRAC group K3) herbicide flufenacet is a key compound in weed resistance management, primarily used for PRE control of grass-weeds in winter cereal-based crop rotations in Europe. Although resistance to compounds of its mode of action (inhibition of the synthesis of very-long chain fatty acids) generally evolves slowly, reduced flufenacet efficacy due to enhanced glutathione transferase (GST) activity has been described in several blackgrass (Alopecurus myosuroides Huds.) populations. The present study aimed to better understand of the mechanism of flufenacet detoxification in A. myosuroides. Therefore, we characterized four A. myosuroides populations with different levels of flufenacet sensitivity. Flufenacet degradation was significantly slowed down in a sensitive population and a population with reduced flufenacet sensitivity by the use of the GST-inhibitors tridiphane and ethacrynic acid at sublethal rates. Finally, six differentially expressed GSTs and nine transcription factors as well as a keto-acyl-CoA reductase, involved in the biosynthesis of very-long-chain fatty acids were identified as candidate genes among a set of 319 significantly higher expressed gene-associated contigs in an RNA-Seq (RNA sequencing) study with the described A. myosuroides populations. Among a set of 218 contigs with significantly lower expression levels, receptor kinase activity was the most frequent annotation. In summary, the likely GST-mediated reduction in sensitivity evolves in A. myosuroides at a slow rate and can partially be reversed by an interaction between flufenacet and the GST-inhibitors tridiphane and ethacrynic acid. This provides further evidence for enhanced GST activity as a key mechanism in flufenacet resistance in A. myosuroides and supports the hypothesis that the six differentially expressed GSTs detected in the present RNA-Seq study are potentially involved in flufenacet resistance.
A non-GMO trait called Inzen™ was recently commercialized in grain sorghum to combat weedy grasses, allowing the use of nicosulfuron POST in the crop. Inzen™ grain sorghum carries a double mutation in the acetolactate synthase (ALS) gene Val560Ile and Trp574Leu, which potentially results in cross-resistance to a wide assortment of ALS-inhibiting herbicides. To evaluate the scope of cross-resistance to Weed Science Society of America Group 2 herbicides in addition to nicosulfuron, tests were conducted in 2016 and 2017 at the Lon Mann Cotton Research Station near Marianna, AR, the Arkansas Agricultural Research and Extension Center in Fayetteville, AR, and in 2016 at the Pine Tree Research Station near Colt, AR. The tests included ALS-inhibiting herbicides from all five families: sulfonylureas, imidazolinones, pyrimidinylthiobenzoics, triazolinones, and triazolopyrimidines. Treatments were made PRE or POST to grain sorghum at a 1X rate for crops in which each herbicide is labeled. Grain sorghum planted in the PRE trial included Inzen™ and a conventional cultivar. Visible estimates of injury and sorghum heights were recorded at 2 and 4 weeks after herbicide application and yield data were collected at crop maturity. In the PRE trial, there was no visible injury, sorghum height reduction, or yield loss in plots containing the Inzen™ cultivar. Applications made POST to the Inzen™ grain sorghum caused visible injury, sorghum height reduction, and yield loss of 20%, 13%, and 35%, respectively, only in plots where bispyribac-Na was applied. There was no impact on the crop from other POST-applied ALS-inhibiting herbicides. These results demonstrate that the Inzen™ trait confers cross-resistance to most ALS-inhibiting herbicides and could offer promising new alternatives for weed control and protection from carryover of residual ALS-inhbiting herbicides in grain sorghum.
Eggs are considered a high-quality protein source for its complete amino acid profile and digestibility. Therefore, this study aimed to compare the effects of the whole egg (WE) vs. egg white (EW) ingestion during 12 weeks of resistance training (RT) on skeletal muscle regulatory markers and body composition in resistance-trained men. Thirty resistance-trained men (24.6 ± 2.7 years) were randomly assigned into a WE + RT (WER; n=15) or EW + RT (EWR; n=15) groups. The WER group ingested three WE while the EWR group ingested an isonitrogenous quantity of six EW per day immediately after the RT session. Serum concentrations of regulatory markers and body composition were measured at baseline and after 12 weeks. Significant main effects of time were observed for bodyweight [WER = 1.7 kg and EWR= 1.8 kg], skeletal muscle mass [WER = 2.9 kg and EWR= 2.7 kg], Fibroblast growth factor 2 [WER = 116.1 pg.ml and EWR= 83.2 pg.ml], and follistatin [WER = 0.05 ng.ml and EWR= 0.04 ng.ml], which significantly increased (p ˂ 0.05); and for fat mass [WER = -1.9 kg and EWR= -1.1 kg], Transforming growth factor-β1 [WER = -0.5 ng.ml and EWR= -0.1 ng.ml], Activin A [WER = -6.2 pg.ml and EWR= -4.5 pg.ml], and myostatin [WER = -0.1 ng.ml and EWR= -0.06 ng.ml], which significantly decreased (p ˂ 0.05) in both the WER and EWR groups. Consumption of eggs absent of yolk during chronic RT results in similar body composition and functional outcomes as WE of equal protein value. EW or WE may be used interchangeably for the dietary support of RT-induced muscular hypertrophy when protein intake is maintained.
To propose cut-off points for the TAG–glucose (TyG) index in Brazilian children and evaluate the link to cardiometabolic risk.
A cross-sectional study with children from a municipality in Minas Gerais, Brazil. Anthropometric (weight, height, waist circumference and waist:height ratio), biochemical (lipid and glucose profile) and blood pressure (BP) tests were performed. Using the receiver operating characteristic curve, cut-off points for the TyG index were proposed according to sex using homoeostasis model of assessment – insulin resistance (IR) as the reference method.
Viçosa, MG, Brazil.
Children aged 4–9 years (n 515).
The TyG index cut-off points to identify the risk of IR were 7·9 and 8·1 for boys and girls, respectively. We observed that 48·7 % of the children had an increased TyG index. The increased TyG index was associated with overweight, total body and central fat, increased BP and altered lipid profile. Children with an increased TyG index had a higher accumulation of cardiometabolic risk factors.
According to the cut-off points proposed by the current study, children at risk of IR estimated by the TyG index presented a higher cardiometabolic risk, including isolated risk factors, as to the higher accumulation of these.
Dietary insulin index directly estimates the postprandial insulin secretion potential of foods, whereas empirical dietary index for hyperinsulinemia (EDIH) assesses insulinemic potential of usual diets based on fasting plasma C-peptide, and is primarily reflective of insulin resistance. It is unknown whether these insulin-related indices are predictive of an integrated measure of insulin secretion. We conducted a cross-sectional analysis that included 293 non-diabetic men with 24-hour urinary C-peptide data from the Men’s Lifestyle Validation Study. EDIH, dietary insulin index, and dietary insulin load were calculated using validated food frequency questionnaires. We conducted multivariable-adjusted linear regression to estimate relative and absolute concentrations of 24-hour urinary C-peptide. In multivariable-adjusted models, we found a significant positive association between all three insulin-related dietary indices and 24-hour urinary C-peptide (P<0.05). Relative concentrations of 24-hour urinary C-peptide per 1-standard deviation increase in insulin-related dietary indices were: 1.12 (95% confidence interval (CI), 1.02, 1.23) for EDIH, 1.18 (95% CI, 1.07, 1.29) for dietary insulin index and 1.16 (95% CI, 1.06, 1.27) for dietary insulin load. When we further adjusted for body mass index (BMI), the association was attenuated for EDIH, to 1.07 (95% CI, 0.98, 1.16), and remained unchanged for dietary insulin index and dietary insulin load. In conclusion, EDIH, dietary insulin index, and dietary insulin load were predictive of integrated insulin secretion assessed by 24-hour urinary C-peptide. Findings after adjustment for BMI appear to confirm the relation of EDIH to insulin resistance and dietary insulin index/load to insulin secretion; the respective constructs of the two dietary indices.
What is it for something to be an artwork, or a particular kind of artwork? What is the nature of the creative processes whereby artworks come into existence? What kinds of cognitive capacities and processes enter into the reception and appreciation of artworks? Philosophers of art have appealed to the imagination in answering each of these questions. I first consider the nature and role of the imagination in traditional conceptions of artistic creation, and why such conceptions are now viewed as more problematic. I then outline Kendall Walton’s highly influential analysis of the nature and appreciation of artistic representations in terms of a kind of imagining that he terms “make-believe.” I also consider Gregory Currie’s analysis of the nature of literary and cinematic fictions in terms of prescriptions to imagine various things, and of the role of the imagination in our engagement with such fictions. I next address recent critical responses to the roles ascribed to the imagination by Walton and Currie. Finally I look briefly at what has been termed the puzzle of “imaginative resistance,” our reluctance to engage in some of the imaginings prescribed by literary and cinematic fictions.
In view of seventeenth-century Protestant humanist transformations, this concluding chapter returns to the Spanish Dominicans and their scholastic-juristic view on the law of nations as a normative resource for thinking about international society. Their Thomistic attention to the rationality of the universal law of nations as positive human law enabled political recognition of non-European polities, the lawful occupants of the Indies. This contrasted with an imperial-humanist jurisprudence that provincialized natural law and the law of nations under European civilizational hierarchy to justify dispossession of inferior peoples. The chapter especially charts the evolution of Las Casas’s thinking through his interaction with the theologians at Salamanca. His eclectic synthesis of Thomistic theology, canon law, Roman law, and humanism to buttress indigenous occupation exemplified a radical scholastic brand of legal humanism that complicates static ideological categories in the history of international legal thought. By placing Las Casas in conversation with his Dominican confreres, a normative view of the law of nations grounded in Christian theological convictions emerges. It accounts for the independence and interdependence of all peoples, and the indispensable role of justice and solidarity in promoting world order under a Christian ethic of loving one’s neighbors.
The concluding chapter describes the equal sharers as nonconformists, resisters of gendered norms, and recounts the social criticism that their lifestyle can evoke. The chapter identifies factors across diverse cultures that enable this resistance. They include couples’ conscious adoption of egalitarian principles and insistence that they be put into practice, which often entails women’s sense of entitlement to equality, and their ongoing communication with their partners. In addition, anti-essentialist beliefs, familism, and anti-materialism underwrite their equality. Lessons from their families of origin, whose lives they either imitate or reject also encourage their resistance to gendered norms. Finally, the chapter enumerates the rewards equal sharing provides for men, women, marriage/partnership, and children.
Intensified cover cropping practices are increasingly viewed as an herbicide resistance management tool but clear distinction between reactive and proactive resistance management performance targets is needed. We evaluated two proactive performance targets for integrating cover cropping tactics, including (1) facilitation of reduced herbicide inputs, and (2) reduced herbicide selection pressure. We conducted corn (Zea mays L.) and soybean [Glycine max (L.) Merr] field experiments in Pennsylvania and Delaware using synthetic weed seedbanks of horseweed [Conyza canadensis (L.) Cronquist] and smooth pigweed (Amaranthus hybridus L.) to assess winter- and summer- annual population dynamics, respectively. The effect of alternative cover crops was evaluated across a range of herbicide inputs. Cover crop biomass production ranged from 2,000 to 8,500 kg ha-1 in corn and 3,000 to 5,500 kg ha-1 in soybean. Experimental results demonstrated that herbicide-based tactics were the primary drivers of total weed biomass production with cover cropping tactics providing an additive weed suppression benefit. Substitution of cover crops for PRE or POST herbicide programs did not reduce total weed control levels or cash crop yields but did result in lower net returns due to higher input costs. Cover cropping tactics significantly reduced C. canadensis populations in three of four cover crop treatments and decreased the number of large rosettes (> 7.6 cm diameter) at the time of pre-plant herbicide exposure. Substitution of cover crops for PRE herbicides resulted in increased selection pressure on POST herbicides, but reduced the number of large individuals (> 10 cm) at POST applications. Collectively, our findings suggest that cover crops can reduce the intensity of selection pressure on POST herbicides but the magnitude of the effect varies based on weed life-history traits. Additional work is needed to describe proactive resistance management concepts and performance targets for integrating cover crops so producers can apply these concepts in site-specific, within-field management practices.
Aphids are phloem-feeding insects that cause economic losses to crops globally. Whilst aphid interactions with susceptible plants and partially resistant genotypes have been well characterized, the interactions between aphids and non-host species are not well understood. Unravelling these non-host interactions can identify the mechanisms which contribute to plant resistance. Using contrasting aphid-host plant systems, including the broad host range pest Myzus persicae (host: Arabidopsis; poor-host: barley) and the cereal pest Rhopalosiphum padi (host: barley; non-host: Arabidopsis), we conducted a range of physiological experiments and compared aphid settling and probing behaviour on a host plant vs either a non-host or poor-host. In choice experiments, we observed that around 10% of aphids selected a non-host or poor-host plant species after 24 h. Using the Electrical Penetration Graph technique, we showed that feeding and probing behaviours differ during non-host and poor-host interactions when compared with a host interaction. In the Arabidopsis non-host interaction with the cereal pest R. padi aphids were unable to reach and feed on the phloem, with resistance likely residing in the mesophyll cell layer. In the barley poor-host interaction with M. persicae, resistance is likely phloem-based as phloem ingestion was reduced compared with the host interaction. Overall, our data suggest that plant resistance to aphids in non-host and poor-host interactions with these aphid species likely resides in different plant cell layers. Future work will take into account specific cell layers where resistances are based to dissect the underlying mechanisms and gain a better understanding of how we may improve crop resistance to aphids.
Electric vehicles are playing an increasingly important role in the agricultural sector. The selection of tyres for reducing energy loss due to rolling resistance is an important consideration in determining the viability of these vehicles. To date little is known about rolling resistance of small all-terrain vehicles. In this study a test rig was used to collect rolling resistance data for seven ATV tyres. The study verifies the relationship between normal load and rolling resistance and gives insight into some of the important considerations when selecting tyres for small off road vehicles.
Mungbean yellow mosaic virus (MYMV) disease is one of the most devastating biotic constraints of mungbean production in India. Dependable knowledge on the number and mode of action of genes controlling resistance to MYMV disease is one of the keys to develop resistant cultivars. The F1s of four crosses derived from four MYMV resistant genotypes × one highly susceptible genotype, their parents, F2s and F3s along with a susceptible check were screened for responses to MYMV disease following the infector-row technique under natural infection conditions. A good fit of F2 population segregation to the hypothesized ratio of 15 susceptible:1 resistant and that of F3 population segregation to the expected ratio of 55 susceptible:9 resistant at 55 days after planting confirmed the involvement of two recessive genes in imparting resistance to MYMV disease.
Throughout eastern Arkansas, Palmer amaranth resistant to protoporphyrinogen oxidase (PPO)-inhibiting herbicides (Group 14) has become widespread. Most PPO-resistant Palmer amaranth biotypes possess a target-site mutation, but a metabolic resistance mechanism to fomesafen (Group 14) has also been identified. Once metabolic resistance manifests, plants may also be tolerant to other herbicides and sites of action. To evaluate whether varying spray parameters affected control of PPO-resistant Palmer amaranth in dicamba-tolerant crops, field trials were conducted in 2017 and 2018 at the Lon Mann Cotton Research Station near Marianna, AR, and on-farm in Marion, AR. The experiment included split plot factors of dicamba rate, nozzle type, and carrier volume, with a whole plot factor of population. Dicamba was applied at 560 or 1120 g ae ha-1 through 110015 TTI or AirMix nozzles at 70 or 140 L ha-1 to PPO-resistant or PPO-susceptible Palmer amaranth. Palmer amaranth control 14 days after treatment (DAT) was influenced by an interaction between population and carrier volume. PPO-resistant Palmer amaranth control 14 DAT was 81% regardless of carrier volume, compared to 90% and 95% control at 70 and 140 L ha-1, respectively, of the PPO-susceptible population. An interaction between nozzle type and carrier volume influenced Palmer amaranth control 21 DAT, where AirMix nozzles at 140 L ha-1 controlled Palmer amaranth at a greater level (94%) than any other nozzle and carrier volume combination (≤90%). An interaction between population and dicamba rate influenced Palmer amaranth relative density 21 DAT. PPO-resistant Palmer amaranth density was less affected by dicamba at either rate than PPO-susceptible Palmer amaranth, relative to the nontreated check. Results concur with those of other research that suggest PPO-resistant Palmer amaranth is harder to control with dicamba. Otherwise, increasing carrier volume affected overall Palmer amaranth control to a greater degree than any other factor.
Parasites cause harm to their hosts and represent pervasive causal agents of natural selection. Understanding host proximate responses during interactions with parasites can help predict which genes and molecular pathways are targets of this selection. In the current study, we examined transcriptional changes arising from interactions between Drosophila melanogaster and their naturally occurring ectoparasitic mite, Gamasodes queenslandicus. Shifts in host transcript levels associated with behavioural avoidance revealed the involvement of genes underlying nutrient metabolism. These genetic responses were reflected in altered body lipid and glycogen levels in the flies. Mite infestation triggered a striking immune response, while male accessory gland protein transcript levels were simultaneously reduced, suggesting a trade-off between host immune responses to parasite challenge and reproduction. Comparison of transcriptional analyses during mite infestation to those during nematode and parasitoid attack identified host genes similarly expressed in flies during these interactions. Validation of the involvement of specific genes with RNA interference lines revealed candidates that may directly mediate fly–ectoparasite interactions. Our physiological and molecular characterization of the Drosophila–Gamasodes interface reveals new proximate mechanisms underlying host–parasite interactions, specifically host transcriptional shifts associated with behavioural avoidance and infestation. The results identify potential general mechanisms underlying host resistance and evolutionarily relevant trade-offs.
A Nutrition Society member-led meeting was held on 9 January 2020 at The University of Surrey, UK. Sixty people registered for the event, and all were invited to participate, either through chairing a session, presenting a ‘3 min lightning talk’ or by presenting a poster. The meeting consisted of an introduction to the topic by Dr Barbara Fielding, with presentations from eight invited speakers. There were also eight lightning talks and a poster session. The meeting aimed to highlight recent research that has used stable isotope tracer techniques to understand human metabolism. Such studies have irrefutably shaped our current understanding of metabolism and yet remain a mystery to many. The meeting aimed to de-mystify their use in nutrition research.
Herbicide resistance has for decades been an increasing problem of agronomic crops such as corn and soybean. Several weed species have evolved herbicide resistance in turfgrass systems such as golf courses, sports fields, and sod production—particularly biotypes of annual bluegrass and goosegrass. Consequences of herbicide resistance in agronomic cropping systems indicate what could happen in turfgrass if herbicide resistance becomes broader in terms of species, distribution, and mechanisms of action. The turfgrass industry must take action to develop effective resistance management programs while this problem is still relatively small in scope. We propose that lessons learned from a series of national listening sessions conducted by the Herbicide Resistance Education Committee of the Weed Science Society of America to better understand the human dimensions affecting herbicide resistance in crop production provide tremendous insight into what themes to address when developing effective resistance management programs for the turfgrass industry.
The evolution of resistance to multiple herbicides in Palmer amaranth is a major challenge for its management. In this study, a Palmer amaranth population from Hutchinson, Kansas (HMR), was characterized for resistance to inhibitors of photosystem II (PSII) (e.g., atrazine), acetolactate synthase (ALS) (e.g., chlorsulfuron), and EPSP synthase (EPSPS) (e.g., glyphosate), and this resistance was investigated. About 100 HMR plants were treated with field-recommended doses (1×) of atrazine, chlorsulfuron, and glyphosate, separately along with Hutchinson multiple-herbicide (atrazine, chlorsulfuron, and glyphosate)–susceptible (HMS) Palmer amaranth as control. The mechanism of resistance to these herbicides was investigated by sequencing or amplifying the psbA, ALS, and EPSPS genes, the molecular targets of atrazine, chlorsulfuron, and glyphosate, respectively. Fifty-two percent of plants survived a 1× (2,240 g ai ha−1) atrazine application with no known psbA gene mutation, indicating the predominance of a non–target site resistance mechanism to this herbicide. Forty-two percent of plants survived a 1× (18 g ai ha−1) dose of chlorsulfuron with proline197serine, proline197threonine, proline197alanine, and proline197asparagine, or tryptophan574leucine mutations in the ALS gene. About 40% of the plants survived a 1× (840 g ae ha−1) dose of glyphosate with no known mutations in the EPSPS gene. Quantitative PCR results revealed increased EPSPS copy number (50 to 140) as the mechanism of glyphosate resistance in the survivors. The most important finding of this study was the evolution of resistance to at least two sites of action (SOAs) (~50% of plants) and to all three herbicides due to target site as well as non–target site mechanisms. The high incidence of individual plants with resistance to multiple SOAs poses a challenge for effective management of this weed.
Herbicide-resistant weeds pose a severe threat to sustainable vegetation management in various production systems worldwide. The majority of the herbicide resistance cases reported thus far originate from agronomic production systems where herbicide use is intensive, especially in industrialized countries. Another notable sector with heavy reliance on herbicides for weed control is managed turfgrass systems, particularly golf courses and athletic fields. Intensive use of herbicides, coupled with a lack of tillage and other mechanical tools that are options in agronomic systems, increases the risk of herbicide-resistant weeds evolving in managed turfgrass systems. Among the notable weed species at high risk for evolving resistance under managed turf systems in the United States are annual bluegrass, goosegrass, and crabgrasses. The evolution and spread of multiple herbicide resistance, an emerging threat facing the turfgrass industry, should be addressed with the use of diversified management tools. Target-site resistance has been reported commonly as a mechanism of resistance for many herbicide groups, though non–target site resistance is an emerging concern. Despite the anecdotal evidence of the mounting weed resistance issues in managed turf systems, the lack of systematic and periodic surveys at regional and national scales means that confirmed reports are very limited and sparse. Furthermore, currently available information is widely scattered in the literature. This review provides a concise summary of the current status of herbicide-resistant weeds in managed turfgrass systems in the United States and highlights key emerging threats.
Weed management is an important issue for nursery crop and Christmas tree producers, as well as for those maintaining turfgrass or ornamental species in landscape plantings. PRE and POST herbicides are important weed management tools for these industries. Reports of herbicide-resistant weeds increased from fewer than 100 cases in 1985 to nearly 500 cases globally in 2019, including ones found in turfgrass or ornamental systems. The evolution, persistence, and management of herbicide-resistant weeds are an ongoing educational process. We must keep our stakeholders aware of improved weed control technology and provide them information on resistant weeds. A symposium at the 2019 Weed Science Society of America meeting was conducted with presentations and discussions by invited speakers in relation to current research and potential management strategies for resistant weeds in turfgrass, landscape ornamental, and nursery crops. To prepare for the symposium, a survey was prepared for nursery producers and landscapers on the issues of herbicide-resistant weeds and offsite movement of herbicides used to control herbicide-resistant weeds. Overall, most respondents felt herbicide-resistant weeds are a serious problem and most had personally observed herbicide resistance on properties they maintain. Resistance to glyphosate was the herbicide cited by most respondents, followed by resistance to triazine herbicides. Most felt their weed-control costs had increased because of resistant weeds. Approximately 20% of respondents had their operation affected by drift of herbicides from nearby farm fields, with most reporting no damage from spray or vapor drift, but a few reported greater than 50% of the crop damaged.