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Статті в журналах з теми "Higher inductive types"
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LUMSDAINE, PETER LEFANU, and MICHAEL SHULMAN. "Semantics of higher inductive types." Mathematical Proceedings of the Cambridge Philosophical Society 169, no. 1 (June 17, 2019): 159–208. http://dx.doi.org/10.1017/s030500411900015x.
Повний текст джерелаАнотація:
AbstractHigher inductive typesare a class of type-forming rules, introduced to provide basic (and not-so-basic) homotopy-theoretic constructions in a type-theoretic style. They have proven very fruitful for the “synthetic” development of homotopy theory within type theory, as well as in formalising ordinary set-level mathematics in type theory. In this paper, we construct models of a wide range of higher inductive types in a fairly wide range of settings.We introduce the notion ofcell monad with parameters: a semantically-defined scheme for specifying homotopically well-behaved notions of structure. We then show that any suitable model category hasweakly stable typal initial algebrasfor any cell monad with parameters. When combined with the local universes construction to obtain strict stability, this specialises to give models of specific higher inductive types, including spheres, the torus, pushout types, truncations, the James construction and general localisations.Our results apply in any sufficiently nice Quillen model category, including any right proper, simplicially locally cartesian closed, simplicial Cisinski model category (such as simplicial sets) and any locally presentable locally cartesian closed category (such as sets) with its trivial model structure. In particular, any locally presentable locally cartesian closed (∞, 1)-category is presented by some model category to which our results apply.
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Sojakova, Kristina. "Higher Inductive Types as Homotopy-Initial Algebras." ACM SIGPLAN Notices 50, no. 1 (May 11, 2015): 31–42. http://dx.doi.org/10.1145/2775051.2676983.
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Cavallo, Evan, and Robert Harper. "Higher inductive types in cubical computational type theory." Proceedings of the ACM on Programming Languages 3, POPL (January 2, 2019): 1–27. http://dx.doi.org/10.1145/3290314.
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Dybjer, Peter, and Hugo Moeneclaey. "Finitary Higher Inductive Types in the Groupoid Model." Electronic Notes in Theoretical Computer Science 336 (April 2018): 119–34. http://dx.doi.org/10.1016/j.entcs.2018.03.019.
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van der Weide, Niels, and Herman Geuvers. "The Construction of Set-Truncated Higher Inductive Types." Electronic Notes in Theoretical Computer Science 347 (November 2019): 261–80. http://dx.doi.org/10.1016/j.entcs.2019.09.014.
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Tan, Qingping. "A higher-order unification algorithm for inductive types and dependent types." Journal of Computer Science and Technology 12, no. 3 (May 1997): 231–43. http://dx.doi.org/10.1007/bf02948973.
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Vezzosi, Andrea, Anders Mörtberg, and Andreas Abel. "Cubical agda: a dependently typed programming language with univalence and higher inductive types." Proceedings of the ACM on Programming Languages 3, ICFP (July 26, 2019): 1–29. http://dx.doi.org/10.1145/3341691.
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Swan, Andrew W. "A class of higher inductive types in Zermelo‐Fraenkel set theory." Mathematical Logic Quarterly 68, no. 1 (January 21, 2022): 118–27. http://dx.doi.org/10.1002/malq.202100040.
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ABEL, ANDREAS. "Polarised subtyping for sized types." Mathematical Structures in Computer Science 18, no. 5 (October 2008): 797–822. http://dx.doi.org/10.1017/s0960129508006853.
Повний текст джерелаАнотація:
We present an algorithm for deciding polarised higher-order subtyping without bounded quantification. Constructors are identified not only modulo β, but also η. We give a direct proof of completeness, without constructing a model or establishing a strong normalisation theorem. Inductive and coinductive types are enriched with a notion of size and the subtyping calculus is extended to account for the inclusions arising between the sized types.
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BERGER, ULRICH, and TIE HOU. "A realizability interpretation of Church's simple theory of types." Mathematical Structures in Computer Science 27, no. 8 (July 22, 2016): 1364–85. http://dx.doi.org/10.1017/s0960129516000104.
Повний текст джерелаАнотація:
We give a realizability interpretation of an intuitionistic version of Church's Simple Theory of Types (CST) which can be viewed as a formalization of intuitionistic higher-order logic. Although definable in CST we include operators for monotone induction and coinduction and provide simple realizers for them. Realizers are formally represented in an untyped lambda–calculus with pairing and case-construct. The purpose of this interpretation is to provide a foundation for the extraction of verified programs from formal proofs as an alternative to type-theoretic systems. The advantages of our approach are that (a) induction and coinduction are not restricted to the strictly positive case, (b) abstract mathematical structures and results may be imported, (c) the formalization is technically simpler than in other systems, for example, regarding the definition of realizability, which is a simple syntactical substitution, and the treatment of nested and simultaneous (co)inductive definitions.
Дисертації з теми "Higher inductive types"
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Girardi, Marco. "Proof theoretical issues in Martin-Löf Type Theory and Homotopy Type Theory." Doctoral thesis, Università degli studi di Trento, 2022. http://hdl.handle.net/11572/348681.
Повний текст джерелаАнотація:
Homotopy Type Theory (HoTT) is a quite recent branch of research in mathematical logic, which provides interesting connections among various areas of mathematics. It was first introduced by Vladimir Voevodsky as a means to develop synthetic homotopy theory, and further advancements suggested that it can be used as a formal foundation to mathematics. Among its notable features, inductive and higher inductive types are of great interest, e.g. allowing for the study of geometric entities (such as spheres) in the setting of HoTT.
However, so far in most of the literature higher inductive types are treated in an ad-hoc way; there is no easy general schema stating what an higher inductive type is, thus hindering the study of the related proof theory. Moreover, although Martin-Löf Type Theory has been deeply and widely studied, many proof theoretic results about its specific variant used in HoTT are folklore, and the proofs are missing.
In this final talk, we provide an overview on some results we obtained, aiming to address these problems. In the first part of the talk, we will discuss a normalization theorem for the type theory underlying HoTT. In the second part of the talk we will propose a general syntax schema to encapsulate a relevant class of higher inductive types, potentially allowing for future study of the proof theory of HoTT enriched with such types.
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Sattler, Christian. "On the complexities of polymorphic stream equation systems, isomorphism of finitary inductive types, and higher homotopies in univalent universes." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/28111/.
Повний текст джерелаАнотація:
This thesis is composed of three separate parts. The first part deals with definability and productivity issues of equational systems defining polymorphic stream functions. The main result consists of showing such systems composed of only unary stream functions complete with respect to specifying computable unary polymorphic stream functions. The second part deals with syntactic and semantic notions of isomorphism of finitary inductive types and associated decidability issues. We show isomorphism of so-called guarded types decidable in the set and syntactic model, verifying that the answers coincide. The third part deals with homotopy levels of hierarchical univalent universes in homotopy type theory, showing that the n-th universe of n-types has truncation level strictly n+1.
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KUSAKARI, Keiichirou, Masahiko SAKAI, and Toshiki SAKABE. "Primitive Inductive Theorems Bridge Implicit Induction Methods and Inductive Theorems in Higher-Order Rewriting." IEICE, 2005. http://hdl.handle.net/2237/9580.
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CHIBA, Yuki, and Keiichirou KUSAKARI. "A Higher-Order Knuth-Bendix Procedure and Its Applications." Institute of Electronics, Information and Communication Engineers, 2007. http://hdl.handle.net/2237/14974.
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Xia, Bing. "Investigation of novel multi-layer spoke-type ferrite interior permanent magnet machines." Thesis, Cranfield University, 2017. http://dspace.lib.cranfield.ac.uk/handle/1826/12320.
Повний текст джерелаАнотація:
The permanent magnet synchronous machines have been attracting more and more attention due to the advantages of high torque density, outstanding efficiency and maturing technologies. Under the urges of mandatory energy efficiency requirements, they are considered as the most potential candidates to replace the comparatively low-efficient induction machines which dominate the industrial market. However, most of the high performance permanent magnet machines are based on high cost rare-earth materials. Thus, there will be huge demands for low-cost high-performance permanent magnet machines. Ferrite magnet is inexpensive and abundant in supply, and is considered as the most promising alternative to achieve the goal of low cost and high performance. In consideration of the low magnetic energy, this thesis explored the recent developments and possible ideas of ferrite machines, and proposed a novel multi-layer spoke-type interior permanent magnet configuration combining the advantages of flux focusing technique and multi-layer structure. With comparable material cost to induction machines, the proposed ferrite magnet design could deliver 27% higher power with 2-4% higher efficiency with exactly the same frame size. Based on the data base of International Energy Agency (IEA), electricity consumed by electric machines reached 7.1PWh in 2006 [1]. Considering that induction machines take up 90% of the overall industrial installation, the potential energy savings is enormous. This thesis contributes in five key aspects towards the investigation and design of low-cost high-performance ferrite permanent magnet machines. Firstly, accurate analytical models for the multi-layer configurations were developed with the consideration of spatial harmonics, and provided effective yet simple way for preliminary design. Secondly, the influence of key design parameters on performance of the multi-layer ferrite machines were comprehensively investigated, and optimal design could be carried out based on the insightful knowledge revealed. Thirdly, systematic investigation of the demagnetization mechanism was carried out, focusing on the three key factors: armature MMF, intrinsic coercivity and working temperature. Anti-demagnetization designs were presented accordingly to reduce the risk of performance degradation and guarantee the safe operation under various loading conditions. Then, comparative study was carried out with a commercial induction machine for verification of the superior performance of the proposed ferrite machine. Without loss of generality, the two machines had identical stator cores, same rotor diameter and stacking length. Under the operating condition of same stator copper loss, the results confirmed the superior performance of the ferrite machine in terms of torque density, power factor and efficiency. Lastly, mechanical design was discussed to reduce the cost of mass production, and the experimental effort on the prototype machine validates the advantageous performance as well as the analytical and FEA predictions.
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Li, Cheng-Chieh, and 李政潔. "The Design of a High Frequency Induction Heating Circuit for Heating in Air Gap Type." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/53856288745654255800.
Повний текст джерелаАнотація:
碩士中原大學
電機工程研究所
96
The induction heating process could reach high efficiency, high quality, and low pollution . The heating technique is important in related fields, especially in the rapid heating on the surface of metal. In this thesis, a high frequency induction heater for heating of conducting working piece has been designed. A load series resonant induction heating system with voltage source full bridge inverter has been constructed and tested . The system can reach low switching losses, low component stresses, and low electromagnetic interferences of power semiconductor devices. Finally, the control characteristics, efficiency, and experiment results with different parameters were measured and analyzed.
Книги з теми "Higher inductive types"
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Maznev, Aleksandr, and Oleg Shatnev. Electric apparatus and circuits of rolling stock. ru: INFRA-M Academic Publishing LLC., 2020. http://dx.doi.org/10.12737/1014641.
Повний текст джерелаАнотація:
Provides information about technical data and design of electrical apparatus of control, monitoring and protection of traction motors of electric rolling stock (EPS), the principles of speed control of locomotives and trains with contactor-resistor and semiconductor converters based on modern element base, a circuit diagram of various types of EPS with manifold and induction motors in modes of traction and braking.
For students of institutions of secondary professional education. It may be useful to students of higher educational institutions, courses of improvement of qualification, the railway workers related to the maintenance and repair of rolling stock.
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Shulman, Michael. Homotopy Type Theory: A Synthetic Approach to Higher Equalities. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198748991.003.0003.
Повний текст джерелаАнотація:
Homotopy type theory and univalent foundations (HoTT/UF) is a new foundation of mathematics, based not on set theory but on “infinity-groupoids”, which consist of collections of objects, ways in which two objects can be equal, ways in which those ways-to-be-equal can be equal, ad infinitum. Though apparently complicated, such structures are increasingly important in mathematics. Philosophically, they are an inevitable result of the notion that whenever we form a collection of things, we must simultaneously consider when two of those things are the same. The “synthetic” nature of HoTT/UF enables a much simpler description of infinity groupoids than is available in set theory, thereby aligning with modern mathematics while placing “equality” back in the foundations of logic. This chapter will introduce the basic ideas of HoTT/UF for a philosophical audience, including Voevodsky’s univalence axiom and higher inductive types.
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Sabbagh, Michel, and John J. Freely Jr. Epiglottitis, Croup, and Stridor. Edited by Matthew D. McEvoy and Cory M. Furse. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780190226459.003.0078.
Повний текст джерелаАнотація:
Stridor is a high-pitched sound representing partially obstructed or turbulent flow in the airway. Stridor can be part of the inspiratory or expiratory phase, depending on the origin of the flow disturbance. This chapter reviews the etiology of stridor and its subtypes. It also focuses on two important pediatric disease states where stridor is a defining characteristic: epiglottitis and croup. Epiglottitis has emerged as an uncommon cause of pediatric airway compromise, with the widespread use of Haemophilus influenza type b vaccination. Croup continues to be a significant cause of stridor, and is much more common, although less life-threatening. Current opinions on initial evaluation, anesthetic induction, intubation, and follow-up care for both diseases are discussed.
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Lorino, Philippe. Inquiry. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198753216.003.0004.
Повний текст джерелаАнотація:
This chapter narrates the efforts of a hospital cardiology department to create its country’s first chronic heart failure (CHF) multidisciplinary unit. With an average treatment cost that was too high, threatening their required funding, the department’s actors strove to reduce it. They analyzed collective activity, made exploratory hypotheses about cost drivers, and developed new performance measurements to verify their hypotheses. This is an example of the social process of inquiry. The chapter presents the pragmatist definition of inquiry, a non-dualist and relational framework, recursively articulated with the concept of habit. It integrates action and thought, narrative and logical thought. The respective roles of the three types of inference identified by Peirce are analyzed: abduction, deduction, and induction. The chapter highlights the mediated and mediating nature of inquiry, illustrated in the hospital case by the reengineering of management indicators, and closes with the major differences between inquiry and the mainstream problem-solving framework.
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Mills, Gary H. Pulmonary disease and anaesthesia. Edited by Philip M. Hopkins. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780199642045.003.0082.
Повний текст джерелаАнотація:
Respiratory adverse events are the commonest complications after anaesthesia and have profound implications for the recovery of the patient and their subsequent health. Outcome prediction related to respiratory disease and complications is vital when determining the risk:benefit balance of surgery and providing informed consent. Surgery produces an inflammatory response and pain, which affects the respiratory system. Anaesthesia produces atelectasis, decreases the drive to breathe, and causes muscle weakness. As the respiratory system ages, closing capacity increases and airway closure becomes an increasing issue, resulting in atelectasis. Increasing comorbidity and polypharmacy reduces the patient’s ability to eliminate drugs. The proportion of major operations on older frailer patients is rising and postoperative recovery becomes more complicated and the demand for critical care rises. At the same time, the population is becoming more obese, producing rapid decreases in end-expiratory lung volume on induction, together with a high incidence of sleep-disordered breathing. Despite this, many high-risk patients are not accurately identified preoperatively, and of those that are admitted to critical care, some are discharged and then readmitted to the intensive care unit with complications. Respiratory diseases may lead to increases in pulmonary vascular resistance and increased load on the right heart. Some lung diseases are primarily fibrotic or obstructive. Some are inflammatory, autoimmune, or vasculitic. Other diseases relate to the drive to breathe, the nerve supply to, or the respiratory muscles themselves. The range of types of respiratory disease is wide and the physiological consequences of respiratory support are complex. Research continues into the best modes of respiratory support in theatre and in the postoperative period and how best to protect the normal lung. It is therefore essential to understand the effects of surgery and anaesthesia and how this impacts existing respiratory disease, and the way this affects the balance between load on the respiratory system and its capacity to cope.
Частини книг з теми "Higher inductive types"
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Vivekanandan, Paventhan. "Code Generation for Higher Inductive Types." In Functional and Constraint Logic Programming, 18–35. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-16202-3_2.
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Lakin, Matthew R., and Andrew M. Pitts. "Resolving Inductive Definitions with Binders in Higher-Order Typed Functional Programming." In Programming Languages and Systems, 47–61. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-00590-9_4.
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Schürmann, Carsten. "A Type-Theoretic Approach to Induction with Higher-Order Encodings." In Logic for Programming, Artificial Intelligence, and Reasoning, 266–81. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/3-540-45653-8_18.
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da Luz, Viviane Kopp, Vívian Ebeling Viana, Gabriela Magalhães da Fonseca, Camila Pegoraro, Luciano Carlos da Maia, and Antonio Costa de Oliveira. "Identification of rice mutants tolerant to cold stress at the germination stage by TILLING." In Mutation breeding, genetic diversity and crop adaptation to climate change, 111–19. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0011.
Повний текст джерелаАнотація:
Abstract Cold stress is a common factor affecting rice culture in temperate regions, which impairs seed germination, crop establishment and grain yield. This work aimed to identify, through a TILLING assay, rice mutant families displaying cold tolerance during the germination stage. The mutant analyses were performed in 4000 M3 plants obtained through chemical mutagenesis with ethyl methanesulfonate. We screened for mutations in the Os03g0103300 (qLTG3-1) gene, which is responsible for cold tolerance during germination. The TILLING assay identified a mutant (516 A3) which was tested for germination efficiency in cold stress (13°C). The mutant genotype showed a higher relative performance in germination and germination velocity index, which was more than 50% higher compared with wild-type. The mutation induction was efficient in creating genetic variability for cold stress tolerance during germination. Gene expression analyses demonstrate that Os03g0103300 was downregulated in stage S3 in the mutant and wild-type plants germinated under cold stress. However, downregulation in the Os03g0103300 gene was less severe in the mutant, which suggests that the expression related to germination ability under cold stress may be detected in the previous stages, embryo activation and weakening of the tissues that cover the embryo. Overall, the mutant 516 A3 presents a new genetic variant for cold tolerance during germination.
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Schreiber, U. "Detection of rapid induction kinetics with a new type of high-frequency modulated chlorophyll fluorometer." In Current topics in photosynthesis, 259–70. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4412-1_24.
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Bado, Souleymane, Fatemeh Maghuly, Vitor Varzea, and Margit Laimer. "Mutagenesis of in vitro explants of Coffea spp. to induce fungal resistance." In Mutation breeding, genetic diversity and crop adaptation to climate change, 344–52. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0036.
Повний текст джерелаАнотація:
Abstract Coffee is one of the most valuable commodity tree crops worldwide. However, it suffers from several devastating diseases and pests, for example coffee leaf rust and coffee berry borer, whose impact is being amplified by changing climatic conditions. Development of new adapted varieties remains a laborious effort by conventional breeding due to the long juvenile period in tree crops. Plant cell/tissue culture represents the ultimate method to produce large amounts of true-to-type healthy plants and of explants for mutation breeding. In fact, mutation induction combined with in vitro cell/tissue culture techniques has proved to be effective for developing improved cultivars of perennial crops. Prior to mutation breeding, cell and tissue radiosensitivity tests to various mutagens need to be performed, so that optimal treatments can be applied for large population development. Thus, different in vitro explants (plantlet, leaf, callus, embryogenic callus, globular and torpedo stage embryos) of Coffea arabica and Coffea canephora were exposed to different gamma-ray doses (0, 10, 15, 20, 40, 60 and 80 Gy). After 9-21 weeks incubation, a radiosensitivity test was conducted on the different explants and LD50 doses corresponding to 50% of viability or survival of callus, embryogenic callus, globular and torpedo stage embryos and 50% growth reduction (GR50) of shoot were also determined. Callus explants showed a relatively high radio-resistance (LD30-LD50 50-100 Gy) in comparison with entire plantlets or embryos (LD30-GR50 8-46 Gy). Globular embryo development into plantlets and also leaf area of irradiated plantlets were more severely affected by irradiation than other explants. It was possible to confirm the relative radio-resistance of unicellular explants compared with multicellular explants. Estimation of optimal mutation induction dosage range for various in vitro explants is important for tree crops, especially for coffee improvement.
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Belabbas, Belkacem, Tayeb Allaoui, Mohamed Tadjine, and Mouloud Denaï. "Higher Performance of the Type 2 Fuzzy Logic Controller for Direct Power Control of Wind Generator Based on a Doubly Fed Induction Generator in Dynamic Regime." In Artificial Intelligence in Renewable Energetic Systems, 215–23. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-73192-6_22.
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Abdalla, Elgailani, Tarig Ahmed, Omar Bakhit, Yasir Gamar, Salih Elshaikh, Yasir Mohammed, and Abdellatif Sulaiman And Hatim Mardi. "Groundnut mutants with end-of-season drought tolerance for the marginal dry lands of North Kordofan State, Sudan." In Mutation breeding, genetic diversity and crop adaptation to climate change, 243–57. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0025.
Повний текст джерелаАнотація:
Abstract Groundnut (Arachis hypogaea L.), produced in the traditional small-scale rainfed sector of Western Sudan, accounts for 80% of the total annual groundnut acreage, producing 70% of the total production. Low productivity of groundnut is a characteristic feature in North Kordofan State, which is characterized as the most vulnerable state to the impact of climate change. Terminal drought stress resulting from reduction in rainfall amount and distribution at the end of the season is the most deleterious drought period, as it coincides with groundnut pod filling and maturation periods. High and stable yields under subsistence farming conditions in North Kordofan State could be realized only by using adapted high-yielding, drought-tolerant genotypes. Mutation induction by gamma-rays of 200 and 300 Gy was utilized to irradiate 500 dry seeds of the Spanish-type groundnut genotypes, Barberton, Sodari, ICGV 89104, ICGV 86743, ICGV 86744 and ICG 221, aiming at increasing the chances of obtaining genotypes with the desired drought-tolerant traits. Mutants were selected from the M3 plants using visual morphological traits. Groundnut mutants at the M4 and M5 generations, advanced by single seed descent, were evaluated for end-of-season drought tolerance. A terminal drought period of 25 days was imposed after 60 days from planting, using a rainout shelter. Mutants that survived 25 days of terminal drought stress were further evaluated for agronomic performance under rainfed field conditions. The groundnut mutant, Barberton-b-30-3-B, produced 1024 kg/ha, a significantly higher mean pod yield over 12 seasons compared with 926 kg/ha for 'Gubeish', the widely grown released check cultivar, showing overall yield advantage of 11%. Under 5 years of participatory research, Barberton-b-30-3-B was ranked the best with yield increment of 21% over 'Gubeish' under the mother trials. The GGE biplot analysis for 12 and five seasons, respectively, showed that Barberton-b-30-3-B was stable and produced a good yield in both high and low rainfall situations. Hence, Barberton-b-30-3-B was found to be a suitable mutant for sustainable profitable yields in the marginal dry lands of North Kordofan State and was officially released as 'Tafra-1' by the National Variety Release Committee during its second meeting of April 2018.
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Lundqvist, Udda. "Scandinavian mutation research during the past 90 years - a historical review." In Mutation breeding, genetic diversity and crop adaptation to climate change, 10–23. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0002.
Повний текст джерелаАнотація:
Abstract In 1928, the Swedish geneticists Herman Nilsson-Ehle and Åke Gustafsson started to act on their own ideas with the first experiments with induced mutations using diploid barley. They started with X-rays and UV irradiation. Very soon the first chlorophyll mutations were obtained and followed by the first 'vital' mutations Erectoides (ert) (Franckowiak and Lundqvist, 2001). Several other valuable mutations were identified as early maturity, high yielding, lodging resistant and characters with altered plant architecture. The experiments expanded to include other different types of irradiation, followed by chemical mutagenesis starting with mustard gas and concluding with sodium azide. The research brought a wealth of observations of general biological importance, such as the physiological effects of radiation as well as the difference in the mutation spectrum with respect to mutagens. This research was non-commercial, even if some mutants have become of important agronomic value. It peaked in activity during the 1950s to 1980s and, throughout, barley was the main experimental crop. About 12,000 different morphological and physiological mutants with a very broad phenotypic diversity were brought together and are incorporated in the Nordic Genetic Resource Centre (NordGen), Sweden. Several important mutant groups have been analysed in more detail genetically, with regard to mutagen specificity and gene cloning. These are: (i) early maturity mutants (Praematurum); (ii) six-rowed and intermedium-spike mutants; (iii) mutants affecting surface wax coating (Eceriferum); and (iv) mutants affecting rachis spike density (Erectoides). Some of these groups are presented in more detail in this review. Once work with induction of mutations began, it was evident that mutations should regularly be included in breeding programmes of crop plants. In Sweden, direct X-ray induced macro-mutants have been successfully released as cultivars, some of them having been used in combination breeding. Their importance for breeding is discussed in more detail.
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Bennett, Elisabeth E. "Puzzling the Picture using Grounded Theory." In Cognitive Analytics, 1778–92. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-2460-2.ch092.
Повний текст джерелаАнотація:
Since the first publication by Glaser and Strauss in 1967, Grounded Theory has become a highly influential research approach in the social sciences. The approach provides techniques and coding strategies for building theory inductively from the “ground up” as concepts within the data earn relevance into an evolving substantive theory. Over time, Grounded Theory has undergone development and adaptations, and the first phases of analysis have been successfully applied to other types of inductive approaches, such as basic qualitative and case studies. The methodological literature can be difficult to navigate for new researchers as well as experienced analysts using the approach for the first time. This article synthesizes the work of various seminal scholars to address the value of grounded theorizing and it builds a picture of what it means to do grounded theory.
Тези доповідей конференцій з теми "Higher inductive types"
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Coquand, Thierry, Simon Huber, and Anders Mörtberg. "On Higher Inductive Types in Cubical Type Theory." In LICS '18: 33rd Annual ACM/IEEE Symposium on Logic in Computer Science. New York, NY, USA: ACM, 2018. http://dx.doi.org/10.1145/3209108.3209197.
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Awodey, Steve, Jonas Frey, and Sam Speight. "Impredicative Encodings of (Higher) Inductive Types." In LICS '18: 33rd Annual ACM/IEEE Symposium on Logic in Computer Science. New York, NY, USA: ACM, 2018. http://dx.doi.org/10.1145/3209108.3209130.
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van der Weide, Niels. "Constructing Higher Inductive Types as Groupoid Quotients." In LICS '20: 35th Annual ACM/IEEE Symposium on Logic in Computer Science. New York, NY, USA: ACM, 2020. http://dx.doi.org/10.1145/3373718.3394803.
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Sojakova, Kristina. "Higher Inductive Types as Homotopy-Initial Algebras." In POPL '15: The 42nd Annual ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages. New York, NY, USA: ACM, 2015. http://dx.doi.org/10.1145/2676726.2676983.
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Kraus, Nicolai. "Constructions with Non-Recursive Higher Inductive Types." In LICS '16: 31st Annual ACM/IEEE Symposium on Logic in Computer Science. New York, NY, USA: ACM, 2016. http://dx.doi.org/10.1145/2933575.2933586.
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Kraus, Nicolai, and Jakob von Raumer. "Path Spaces of Higher Inductive Types in Homotopy Type Theory." In 2019 34th Annual ACM/IEEE Symposium on Logic in Computer Science (LICS). IEEE, 2019. http://dx.doi.org/10.1109/lics.2019.8785661.
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Baunsgaard Kristensen, Magnus, Rasmus Ejlers Mogelberg, and Andrea Vezzosi. "Greatest HITs: Higher inductive types in coinductive definitions via induction under clocks." In LICS '22: 37th Annual ACM/IEEE Symposium on Logic in Computer Science. New York, NY, USA: ACM, 2022. http://dx.doi.org/10.1145/3531130.3533359.
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Hu, Binbin, Zhengwei Wu, Jun Zhou, Ziqi Liu, Zhigang Huangfu, Zhiqiang Zhang, and Chaochao Chen. "MERIT: Learning Multi-level Representations on Temporal Graphs." In Thirty-First International Joint Conference on Artificial Intelligence {IJCAI-22}. California: International Joint Conferences on Artificial Intelligence Organization, 2022. http://dx.doi.org/10.24963/ijcai.2022/288.
Повний текст джерелаАнотація:
Recently, representation learning on temporal graphs has drawn increasing attention, which aims at learning temporal patterns to characterize the evolving nature of dynamic graphs in real-world applications. Despite effectiveness, these methods commonly ignore the individual- and combinatorial-level patterns derived from different types of interactions (e.g.,user-item), which are at the heart of the representation learning on temporal graphs. To fill this gap, we propose MERIT, a novel multi-level graph attention network for inductive representation learning on temporal graphs.We adaptively embed the original timestamps to a higher, continuous dimensional space for learn-ing individual-level periodicity through Personalized Time Encoding (PTE) module. Furthermore, we equip MERIT with Continuous time and Con-text aware Attention (Coco-Attention) mechanism which chronologically locates most relevant neighbors by jointly capturing multi-level context on temporal graphs. Finally, MERIT performs multiple aggregations and propagations to explore and exploit high-order structural information for down-stream tasks. Extensive experiments on four public datasets demonstrate the effectiveness of MERITon both (inductive / transductive) link prediction and node classification task.
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Altenkirch, Thorsten, and Luis Scoccola. "The Integers as a Higher Inductive Type." In LICS '20: 35th Annual ACM/IEEE Symposium on Logic in Computer Science. New York, NY, USA: ACM, 2020. http://dx.doi.org/10.1145/3373718.3394760.
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Al-Sibahi, Ahmad Salim, Thomas P. Jensen, Aleksandar S. Dimovski, and Andrzej Wąsowski. "Verification of high-level transformations with inductive refinement types." In GPCE '18: 17th ACM SIGPLAN International Conference on Generative Programming: Concepts and Experiences. New York, NY, USA: ACM, 2018. http://dx.doi.org/10.1145/3278122.3278125.
Повний текст джерелаЗвіти організацій з теми "Higher inductive types"
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Paradis, S., S. E. Jackson, D. Petts, G. J. Simandl, R. J. D'Souza, and T S Hamilton. Distribution of trace elements in pyrite from carbonate-hosted sulfide deposits of southern British Columbia. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/328002.
Повний текст джерелаАнотація:
This paper combines petrography with in situ laser-ablation inductively coupled plasma mass spectrometry to document trace-element variations in pyrite (Py) from Mississippi Valley-type (MVT) and fracture-controlled replacement (FCR) deposits in the Kootenay Arc, British Columbia. Three generations of pyrite are Py 1, Py 2, and Py 3. Pyrite 1, the earliest (occurring in MVT deposits only), has higher Ag, Ba, Cu, Ge, Pb, Sb, Sr, Tl, and V than adjacent Py 3. It has higher Ag, Au, Ba, Cu, Ge, Pb, and Tl than Py 2. Pyrite 2 occurs in MVT and FCR deposits. Relative to FCR Py 2, MVT Py 2 is enriched in Co, Ni, Mo, Ba, Tl, and Pb and depleted in other elements. The FCR Py 2 has growth-related compositional banding, which is absent in MVT Py 2. The FCR Py 2 has Ag, Cu, Ga, Ge, In, Sn, and Zn enriched cores, intermediate Au- and As-rich bands, and Co- and Ni-rich rims. Pyrite 3, the latest occurring pyrite, present in MVT and FCR deposits, is enriched in Co and Ni near overgrowths or infillings of sphalerite. Variations in composition of Py reflect mineralogy, characteristics of ore-forming fluids, and differences in physicochemical conditions between MVT and FCR deposits at the time of ore deposition.
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Coplin, David, Isaac Barash, and Shulamit Manulis. Role of Proteins Secreted by the Hrp-Pathways of Erwinia stewartii and E. herbicola pv. gypsophilae in Eliciting Water-Soaking Symptoms and Initiating Galls. United States Department of Agriculture, June 2001. http://dx.doi.org/10.32747/2001.7580675.bard.
Повний текст джерелаАнотація:
Many bacterial pathogens of plants can inject pathogenicity proteins into host cells using a specialized type III secretion system encoded by hrpgenes. This system deliver effector proteins, into plant cells that function in both susceptible and resistant interactions. We have found that the virulence of Erwinia stewartii(Es; syn. Pantoea stewartii) and Erwinia herbicola pv. gypsophilae (Ehg, syn. Pantoea agglomerans), which cause Stewart's wilt of corn and galls on Gypsophila, respectively, depends on hrpgenes. The major objectives of this project were: To increase expression of hrpgenes in order to identify secreted proteins; to identify genes for proteins secreted by the type-III systems and determine if they are required for pathogenicity; and to determine if the secreted proteins can function within eukaryotic cells. We found that transcription of the hrp and effector genes in Es and Ehg is controlled by at least four genes that constitute a regulatory cascade. Environmental and/or physiological signaling appears to be mediated by the HrpX/HrpY two component system, with HrpX functioning as a sensor-kinase and HrpY as a response regulator. HrpYupregulateshrpS, which encodes a transcriptional enhancer. HrpS then activates hrpL, which encodes an alternate sigma factor that recognizes "hrp boxes". All of the regulatory genes are essential for pathogenicity, except HrpX, which appears only to be required for induction of the HR in tobacco by Es. In elucidating this regulatory pathway in both species, we made a number of significant new discoveries. HrpX is unusual for a sensor-kinase because it is cytoplasmic and contains PAS domains, which may sense the redox state of the bacterium. In Es, a novel methyl-accepting protein may function upstream of hrpY and repress hrp gene expression in planta. The esaIR quorum sensing system in Es represses hrp gene expression in Es in response to cell-density. We have discovered six new type III effector proteins in these species, one of which (DspE in Ehg and WtsE in Es) is common to both pathogens. In addition, Es wtsG, which is a homolog of an avrPpiB from P. syringae pv. pisi, and an Ehg ORF, which is a homolog of P. syringae pv. phaseolicola AvrPphD, were both demonstrated to encode virulence proteins. Two plasmidborne, Ehg Hop proteins, HsvG and PthG, are required for infection of gypsophilia, but interestingly, PthG also acts as an Avr elicitor in beets. Using a calmodulin-dependent adenylate cyclase (cyaA) reporter gene, we were successful in demonstrating that an HsvG-CyaA fusion protein can be transferred into human HeLa cells by the type-III system of enteropathogenic E. coli. This is a highly significant accomplishment because it is the first direct demonstration that an effector protein from a plant pathogenic bacterium is capable of being translocated into a eukaryotic cell by a type-III secretion system. Ehg is considered a limiting factor in Gypsophila production in Israel and Stewart’s Wilt is a serious disease in the Eastern and North Central USA, especially on sweet corn in epidemic years. We believe that our basic research on the characterization of type III virulence effectors should enable future identification of their receptors in plant cells. This may lead to novel approaches for genetically engineering resistant plants by modifying their receptors or inactivating effectors and thus blocking the induction of the susceptible response. Alternatively, hrp gene regulation might also provide a target for plant produced compounds that interfere with recognition of the host by the pathogen. Such strategies would be broadly applicable to a wide range of serious bacterial diseases on many crops throughout the USA and Israel.
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Lers, Amnon, and Pamela J. Green. LX Senescence-Induced Ribonuclease in Tomato: Function and Regulation. United States Department of Agriculture, September 2003. http://dx.doi.org/10.32747/2003.7586455.bard.
Повний текст джерелаАнотація:
Natural leaf senescence, which occurs even when growth conditions are near optimal, has a negative influence on yield. Postharvest induced senescence contributes to the losses of quality in flowers, foliage, and vegetables. Strategies designed to control the senescence process in crop plants could therefore have great applied significance. However, the successful design of such strategies requires a better insight into the senescence machinery and control in higher plants. A main feature of senescence is the hydrolysis of macromolecules by hydrolases of various types such as ribonucleases (RNases) and proteases. Previously we had identified and characterized the tomato LX RNase gene demonstrating its transcript to be highly and specifically induced during senescence. This reported study was focused on LX but also had broadened our research to other senescence-associated nucleic acids degrading enzymes to learn about their function and the regulation of their encoding genes. Beside tomato we used parsley and Arabidopsis for the study of: the bi-functional nuclease which has a role in senescence. The study of different senescence- associated nucleases in few plant systems will allow a more general view on function and regulation of these enzymes in senescence. The specific original proposed objectives included: 1. Study the consequences of alterations in LX RNase level on tomato leaf senescence and general development; 2. Analyze stimuli which may participate in senescence-specific activation of the LX gene; 3. Clone the senescence-associated BFNI nuclease gene homologue from tomato. 4. Further characterize the sequences required for senescence-specific gene expression. Homozygous transgenic plants in which LX gene was either inhibited or over-expressed were generated. In both of these LX mutated plants no major phenotypic consequences were observed, which may suggests that LX is not essential for plant growth under optimal growth conditions. Lack of any abnormalities in the LX over-expressing lines suggests that special system exist to allow function of the RNase only when needed. Detailed analyses of growth under stress and consequences to RNA metabolism are underway. We have analyzed LX expression on the protein level demonstrating that it is involved also in petal senescing. Our results suggest that LX is responding to complex regulation involving developmental, organ dependent factors and responds differently to hormonal or environmental stimuli in the different plant organs. The cloned 1.4 kb promoter was cloned and its analysis revealed that probably not all required elements for senescence induction are included. Biochemical analysis of senescence-associated be-functional nucleases in the different plants, tomato, parsley and Arabidopsis, suggests they belong to a sub-class within the type I plant nucleases. The parsley PcNUC1/2 nuclease protein was purified from senescing leaves its and activity was studied in vitro revealing endo-, double strand, nucleolytic activity and exo-nucleolytic activity. Its encoding gene was cloned and found to be induced on the mRNA level. The promoter of the related Arabidopsis BFNI nuclease was shown in both tomato and Arabidopsis to be able and direct senescence-specific expression suggesting that, at least part, the gene is regulated on the transcriptional level and that the mechanism for this senescence-specific regulation is conserved between different plants. Few plants in which the BFNI gene is mutated were identified which are subjected now to detailed analysis. Our results suggest that the senescence-related nucleic acid degrading enzymes share similarities in both function and regulation between different plants and possibly have important functions in processes un-related to senescence. Still, the function of these enzymes, at least in some cases is not essential to plant development under optimal growth conditions. We are now at the stage which permits in depth investigation of the specific functions and mode of molecular regulation of senescence-associated nucleases with the aid of the research tools developed. The isolated senescence-specific promoter, shown to be active in heterologous plant system, could be utilized in agricultural-related biotechnological applications for retardation of senescence.
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Eshed, Yuval, and John Bowman. Harnessing Fine Scale Tuning of Endogenous Plant Regulatory Processes for Manipulation of Organ Growth. United States Department of Agriculture, 2005. http://dx.doi.org/10.32747/2005.7696519.bard.
Повний текст джерелаАнотація:
Background and objectives: Manipulation of plant organ growth is one of the primary reasons for the success of mankind allowing increasing amounts of food for human and livestock consumption. In contrast with the successful selection for desirable growth characteristics using plant breeding, transgenic manipulations with single genes has met limited success. While breeding is based on accumulation of many small alterations of growth, usually arise from slight changes in expression patterns, transgenic manipulations are primarily based on drastic, non-specific up-regulation or knock down of genes that can exert different effects during different stages of development. To successfully harness transgenic manipulation to attain desirable plant growth traits we require the tools to subtly regulate the temporal and spatial activity of plant growth genes. Polar morphology along the adaxial/abaxial axis characterizes lateral organs of all plants. Juxtaposition of two cell types along this axis is a prerequisite of laminar growth induction. In the study summarized here, we addressed the following questions: Can we identify and harness components of the organ polarity establishment pathway for prolonged growth? Can we identify specific regulatory sequences allowing spatial and temporal manipulation in various stages of organ development? Can we identify genes associated with YABBY-induced growth alterations? Major conclusions and implications: We showed that regulated expression, both spatially and temporally of either organ polarity factors such as the YABBY genes, or the organ maturation program such as the CIN-TCPs can stimulate substantial growth of leaves and floral organs. Promoters for such fine manipulation could be identified by comparison of non-coding sequences of KAN1, where a highly conserved domain was found within the second intron, or by examination of multiple 5” regions of genes showing transient expression along leaf ontogeny. These promoters illustrate the context dependent action of any gene we examined thus far, and facilitate fine tuning of the complex growth process. Implications, both scientific and agricultural. The present study was carried out on the model organism Arabidopsis, and the broad application of its findings were tested in the tomato crop. We learned that all central regulators of organ polarity are functionally conserved, probably in all flowering plants. Thus, with minor modifications, the rules and mechanisms outlined in this work are likely to be general.
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Miller, Gad, and Jeffrey F. Harper. Pollen fertility and the role of ROS and Ca signaling in heat stress tolerance. United States Department of Agriculture, January 2013. http://dx.doi.org/10.32747/2013.7598150.bard.
Повний текст джерелаАнотація:
The long-term goal of this research is to understand how pollen cope with stress, and identify genes that can be manipulated in crop plants to improve reproductive success during heat stress. The specific aims were to: 1) Compare heat stress dependent changes in gene expression between wild type pollen, and mutants in which pollen are heat sensitive (cngc16) or heat tolerant (apx2-1). 2) Compare cngc16 and apx2 mutants for differences in heat-stress triggered changes in ROS, cNMP, and Ca²⁺ transients. 3) Expand a mutant screen for pollen with increased or decreased thermo-tolerance. These aims were designed to provide novel and fundamental advances to our understanding of stress tolerance in pollen reproductive development, and enable research aimed at improving crop plants to be more productive under conditions of heat stress. Background: Each year crop yields are severely impacted by a variety of stress conditions, including heat, cold, drought, hypoxia, and salt. Reproductive development in flowering plants is highly sensitive to hot or cold temperatures, with even a single hot day or cold night sometimes being fatal to reproductive success. In many plants, pollen tube development and fertilization is often the weakest link. Current speculation about global climate change is that most agricultural regions will experience more extreme environmental fluctuations. With the human food supply largely dependent on seeds, it is critical that we consider ways to improve stress tolerance during fertilization. The heat stress response (HSR) has been intensively studied in vegetative tissues, but is poorly understood during reproductive development. A general paradigm is that HS is accompanied by increased production of reactive oxygen species (ROS) and induction of ROS-scavenging enzymes to protect cells from excess oxidative damage. The activation of the HSR has been linked to cytosolic Ca²⁺ signals, and transcriptional and translational responses, including the increased expression of heat shock proteins (HSPs) and antioxidative pathways. The focus of the proposed research was on two mutations, which have been discovered in a collaboration between the Harper and Miller labs, that either increase or decrease reproductive stress tolerance in a model plant, Arabidopsis thaliana (i.e., cngc16--cyclic nucleotide gated channel 16, apx2-1--ascorbate peroxidase 2,). Major conclusions, solutions, achievements. Using RNA-seq technology, the expression profiles of cngc16 and apx2 pollen grains were independently compared to wild type under favourable conditions and following HS. In comparison to a wild type HSR, there were 2,776 differences in the transcriptome response in cngc16 pollen, consistent with a model in which this heat-sensitive mutant fails to enact or maintain a normal wild-type HSR. In a comparison with apx2 pollen, there were 900 differences in the HSR. Some portion of these 900 differences might contribute to an improved HSR in apx2 pollen. Twenty-seven and 42 transcription factor changes, in cngc16 and apx2-1, respectively, were identified that could provide unique contributions to a pollen HSR. While we found that the functional HS-dependent reprogramming of the pollen transcriptome requires specific activity of CNGC16, we identified in apx2 specific activation of flavonol-biosynthesis pathway and auxin signalling that support a role in pollen thermotolerance. Results from this study have identified metabolic pathways and candidate genes of potential use in improving HS tolerance in pollen. Additionally, we developed new FACS-based methodology that can quantify the stress response for individual pollen in a high-throughput fashion. This technology is being adapted for biological screening of crop plant’s pollen to identify novel thermotolerance traits. Implications, both scientific and agricultural. This study has provided a reference data on the pollen HSR from a model plant, and supports a model that the HSR in pollen has many differences compared to vegetative cells. This provides an important foundation for understanding and improving the pollen HSR, and therefor contributes to the long-term goal of improving productivity in crop plants subjected to temperature stress conditions. A specific hypothesis that has emerged from this study is that pollen thermotolerance can be improved by increasing flavonol accumulation before or during a stress response. Efforts to test this hypothesis have been initiated, and if successful have the potential for application with major seed crops such as maize and rice.
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Manulis-Sasson, Shulamit, Christine D. Smart, Isaac Barash, Laura Chalupowicz, Guido Sessa, and Thomas J. Burr. Clavibacter michiganensis subsp. michiganensis-tomato interactions: expression and function of virulence factors, plant defense responses and pathogen movement. United States Department of Agriculture, February 2015. http://dx.doi.org/10.32747/2015.7594405.bard.
Повний текст джерелаАнотація:
Clavibactermichiganensissubsp. michiganensis(Cmm), the causal agent of bacterial wilt and canker of tomato, is the most destructive bacterial disease of tomato causing substantial economic losses in Israel, the U.S.A. and worldwide. The goal of the project was to unravel the molecular strategies that allow Cmm, a Gram-positive bacterium, to develop a successful infection in tomato. The genome of Cmm contains numerous genes encoding for extracellular serine proteases and cell wall degrading enzymes. The first objective was to elucidate the role of secreted serine proteases in Cmm virulence. Mutants of nine genes encoding serine proteases of 3 different families were tested for their ability to induce wilting, when tomato stems were puncture-inoculated, as compared to blisters formation on leaves, when plants were spray-inoculated. All the mutants showed reduction in wilting and blister formation as compared to the wild type. The chpCmutant displayed the highest reduction, implicating its major role in symptom development. Five mutants of cell wall degrading enzymes and additional genes (i.e. perforin and sortase) caused wilting but were impaired in their ability to form blisters on leaves. These results suggest that Cmm differentially expressed virulence genes according to the site of penetration. Furthermore, we isolated and characterized two Cmmtranscriptional activators, Vatr1 and Vatr2 that regulate the expression of virulence factors, membrane and secreted proteins. The second objective was to determine the effect of bacterial virulence genes on movement of Cmm in tomato plants and identify the routes by which the pathogen contaminates seeds. Using a GFP-labeledCmm we could demonstrate that Cmm extensively colonizes the lumen of xylem vessels and preferentially attaches to spiral secondary wall thickening of the protoxylem and formed biofilm-like structures composed of large bacterial aggregates. Our findings suggest that virulence factors located on the chp/tomAPAI or the plasmids are required for effective movement of the pathogen in tomato and for the formation of cellular aggregates. We constructed a transposon plasmid that can be stably integrated into Cmm chromosome and express GFP, in order to follow movement to the seeds. Field strains from New York that were stably transformed with this construct, could not only access seeds systemically through the xylem, but also externally through tomato fruit lesions, which harbored high intra-and intercellular populations. Active movement and expansion of bacteria into the fruit mesocarp and nearby xylem vessels followed, once the fruit began to ripen. These results highlight the ability of Cmm to invade tomato fruit and seed through multiple entry routes. The third objective was to assess correlation between disease severity and expression levels of Cmm virulence genes and tomato defense genes. The effect of plant age on expression of tomato defense related proteins during Cmm infection was analyzed by qRT-PCR. Five genes out of eleven showed high induction at early stages of infection of plants with 19/20 leaves compared to young plants bearing 7/8 leaves. Previous results showed that Cmm virulence genes were expressed at early stages of infection in young plants compared to older plants. Results of this study suggest that Cmm virulence genes may suppress expression of tomato defense-related genes in young plants allowing effective disease development. The possibility that chpCis involved in suppression of tomato defense genes is currently under investigation by measuring the transcript level of several PR proteins, detected previously in our proteomics study. The fourth objective was to define genome location and stability of virulence genes in Cmm strains. New York isolates were compared to Israeli, Serbian, and NCPPB382 strains. The plasmid profiles of New York isolates were diverse and differed from both Israeli and Serbian strains. PCR analysis indicated that the presence of putative pathogenicity genes varied between isolates and highlighted the ephemeral nature of pathogenicity genes in field populations of Cmm. Results of this project significantly contributed to the understanding of Cmm virulence, its movement within tomato xylem or externally into the seeds, the role of serine proteases in disease development and initiated research on global regulation of Cmm virulence. These results form a basis for developing new strategies to combat wilt and canker disease of tomato.
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Yahav, Shlomo, John McMurtry, and Isaac Plavnik. Thermotolerance Acquisition in Broiler Chickens by Temperature Conditioning Early in Life. United States Department of Agriculture, 1998. http://dx.doi.org/10.32747/1998.7580676.bard.
Повний текст джерелаАнотація:
The research on thermotolerance acquisition in broiler chickens by temperature conditioning early in life was focused on the following objectives: a. To determine the optimal timing and temperature for inducing the thermotolerance, conditioning processes and to define its duration during the first week of life in the broiler chick. b. To investigate the response of skeletal muscle tissue and the gastrointestinal tract to thermal conditioning. This objective was added during the research, to understand the mechanisms related to compensatory growth. c. To evaluate the effect of early thermo conditioning on thermoregulation (heat production and heat dissipation) during 3 phases: (1) conditioning, (2) compensatory growth, (3) heat challenge. d. To investigate how induction of improved thermotolerance impacts on metabolic fuel and the hormones regulating growth and metabolism. Recent decades have seen significant development in the genetic selection of the meat-type fowl (i.e., broiler chickens); leading to rapid growth and increased feed efficiency, providing the poultry industry with heavy chickens in relatively short growth periods. Such development necessitates parallel increases in the size of visceral systems such as the cardiovascular and the respiratory ones. However, inferior development of such major systems has led to a relatively low capability to balance energy expenditure under extreme conditions. Thus, acute exposure of chickens to extreme conditions (i.e., heat spells) has resulted in major economic losses. Birds are homeotherms, and as such, they are able to maintain their body temperature within a narrow range. To sustain thermal tolerance and avoid the deleterious consequences of thermal stresses, a direct response is elicited: the rapid thermal shock response - thermal conditioning. This technique of temperature conditioning takes advantage of the immaturity of the temperature regulation mechanism in young chicks during their first week of life. Development of this mechanism involves sympathetic neural activity, integration of thermal infom1ation in the hypothalamus, and buildup of the body-to-brain temperature difference, so that the potential for thermotolerance can be incorporated into the developing thermoregulation mechanisms. Thermal conditioning is a unique management tool, which most likely involves hypothalamic them1oregulatory threshold changes that enable chickens, within certain limits, to cope with acute exposure to unexpected hot spells. Short-tem1 exposure to heat stress during the first week of life (37.5+1°C; 70-80% rh; for 24 h at 3 days of age) resulted in growth retardation followed immediately by compensatory growth" which resulted in complete compensation for the loss of weight gain, so that the conditioned chickens achieved higher body weight than that of the controls at 42 days of age. The compensatory growth was partially explained by its dramatic positive effect on the proliferation of muscle satellite cells which are necessary for further muscle hypertrophy. By its significant effect of the morphology and functioning of the gastrointestinal tract during and after using thermal conditioning. The significant effect of thermal conditioning on the chicken thermoregulation was found to be associated with a reduction in heat production and evaporative heat loss, and with an increase in sensible heat loss. It was further accompanied by changes in hormones regulating growth and metabolism These physiological responses may result from possible alterations in PO/AH gene expression patterns (14-3-3e), suggesting a more efficient mechanism to cope with heat stress. Understanding the physiological mechanisms behind thermal conditioning step us forward to elucidate the molecular mechanism behind the PO/AH response, and response of other major organs. The thermal conditioning technique is used now in many countries including Israel, South Korea, Australia, France" Ecuador, China and some places in the USA. The improvement in growth perfom1ance (50-190 g/chicken) and thermotolerance as a result of postnatal thermal conditioning, may initiate a dramatic improvement in the economy of broiler's production.
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McElwain, Terry F., Eugene Pipano, Guy H. Palmer, Varda Shkap, Stephn A. Hines, and Wendy C. Brown. Protection of Cattle against Babesiosis: Immunization against Babesia bovis with an Optimized RAP-1/Apical Complex Construct. United States Department of Agriculture, September 1999. http://dx.doi.org/10.32747/1999.7573063.bard.
Повний текст джерелаАнотація:
Previous research and current efforts at control of babesiosis fall short of meeting the needs of countries where the disease is endemic, such as Israel, as well as the needs of exporting countries and countries bordering on endemic areas, such as the U.S. Our long-term goal is to develop improved methods of immunization against bovine babesiosis based on an understanding of the molecular mechanisms of immune protection and parasite targets of a protective immune response. In our previous BARD project, we established the basis for focusing on rhoptry antigens as components of a subunit vaccine against bovine babesiosis, and for additional research to better characterize rhoptry associated protein-1 (RAP-1) as a target of protective immunity. In this continuation BARD project, our objectives were to [1] optimize the immune response against RAP-1, and [2] identify additional rhoptry candidate vaccine antigens. The entire locus encoding B. bovis RAP-1 was sequenced, and the rap-1 open reading frame compared among several strains. Unlike B. bigemina, in which multiple gene copies with variant domains encode RAP-1, the B. bovis RAP-1 locus contains only two identical genes which are conserved among strains. Through testing of multiple truncated constructs of rRAP-1, one or more immunodominant T cell epitopes were mapped to the amino terminal half of RAP-1. At least one linear and one conformational B cell epitope have been demonstrated in the same amino terminal construct, which in B. bigemina RAP-1 also contains an epitope recognized by neutralizing antibody. The amine terminal half of the molecule represents the most highly conserved part of the gene family and contains motifs conserved broadly among the apicomplexa. In contrast, the carboxy terminal half of B. bovis RAP-1 is less well conserved and contains multiple repeats encoding a linear B cell epitope potentially capable of inducing an ineffective, T cell independent, type 2 immune response. Therefore, we are testing an amino terminal fragment of RAP-1 (RAP-1N) in an immunization trial in cattle. Cattle have beer immunized with RAP-1N or control antigen, and IL-12 with Ribi adjuvant. Evaluation of the immune response is ongoing, and challenge with virulent B. bovis will occur in the near future. While no new rhoptry antigens were identified, our studies did identify and characterize a new spherical body antigen (SBP3), and several heat shock proteins (HSP's). The SBP3 and HSP21 antigens stimulate T cells from immune cattle and are considered new vaccine candidates worthy of further testing. Overall, we conclude that a single RAP-1 vaccine construct representing the conserved amino terminal region of the molecule should be sufficient for immunization against all strains of B. bovis. While results of the ongoing immunization trial will direct our next research steps, results at this time are consistent with our long term goal of designing a subunit vaccine which contains only the epitopes relevant to induction of protective immunity. Parallel studies are defining the mechanisms of protective immunity. Apicomplexan protozoa, including babesiosis and malaria, cause persistent diseases for which control is inadequate. The apical organelles are defining features of these complex protozoa, and have been conserved through the evolutionary process, Past and current BARD projects on babesiosis have established the validity and potential of exploiting these conserved organelles in developing improved control methods applicable to all apicomplexan diseases.